Germany, theoretical physics, and string theory

DEUTSCH

One year after my report about our bike trip to Gross Arber, I will declare another German week on this blog and contemplate about the relations between Germany on one side and theoretical physics and string theory on the other side as seen from a Czech physicist's viewpoint. The reason is that the number of German visitors is going to double or triple. Many features of the Czech academic system as well as the general mood in the physics community resemble their German counterparts which could make my opinions slightly relevant even if I don't know the current facts about German science at a visceral level.



One hundred years or so, Germany became the world's epicenter of theoretical physics much like it was the leader in philosophy and music one or two centuries earlier. Why do I think so? Let us look at the key achievements one by one. Relativity was developed by Albert Einstein who was a German Jew. Because of certain infamous historical events, he has experienced some problems in Germany; Einstein also faced anti-Semitism in Prague around 1910 when he appreciated the equivalence principle for the first time.

He eventually became a part of the generous gift of Germany to the American science. Max Planck kickstarted quantum theory in 1900. He was also the editor of Annalen der Physik who was responsible for the immediate acceptance of Einstein's paper on special relativity. You should add many leading mathematicians of the early 20th century who were Germans or who spoke German.



The most important physics revolution of the 20th century was arguably the quantum mechanical revolution. Besides Sir Paul Adrien Maurice Dirac of England, Niels Bohr of Denmark, and a few others, this revolution was the work of precious German (or Austrian) physicists and mathematicians. Werner Heisenberg, Johann von Neumann, Erwin Schrödinger, Wolfgang Pauli, and many of their colleagues were the key players in the most thrilling developments in physics of the last century. There's no doubt that this German leading role in theoretical physics has mostly evaporated after the war. Insights such as Quantum Electrodynamics, Quantum Chromodynamics, the Standard Model, and String Theory (except for a couple of important discoveries at the very beginning) were dominated by the American physicists.

Why was it so? No doubt, Germany has paid a tax for the official ideology that took over in 1933 and that couldn't be sustainable for 1000 years. It has also paid for the lost war which is related to the previous sentence but it is not equivalent. Moreover, America became a leader in many other fields of human activity and the American scientists have had a lot of good luck after the war. Nevertheless, I feel that the main reason is different and I will call it "intellectual conservatism of the Central European science". Before we will look at these subtle issues, let us sketch the German role in the current developments in string theory.

German-speaking string theorists

There are actually quite many string theorists from Germany and Austria. Many of them are our friends, many of them have made very important contributions to string theory, and many of them are famous. The readers from Germany might find a list of some countrymates who are working in the field of string theory and closely related fields. The list below is in no way pretended to be complete or representative. Later, I will try to add the names that I forgot and that shouldn't be missing.

• Wolfgang Lerche who has together with Dieter Lüst and Bert Schellekens, among many other things, proposed the huge number of the stringy vacua 20 years before it became fashionable to talk about them
• Katrin Becker
• Melanie Becker (both sisters wrote not only great research papers but also a new string theory textbook with John Schwarz that you simply can't miss)
• Julius Wess, a supersymmetry expert and co-author of a famous book
• Axel Krause who is an expert in heterotic superstring phenomenology
• Volker Braun who likes to construct heterotic Standard Models
• Herman Nicolai who is a key player in the supergravity community, one that has fully merged with the string theory community after the discovery of M-theory
• Andreas Karch who is a famous superstring phenomenologist and a co-author of some well-known papers with Lisa Randall, among many others
• Dieter Lüst who is incidentally also the first co-author of a string theory textbook (link)
• Susanne Reffert, a charming expert in algebraic geometry and flux compactifications
• Urs Schreiber (blog) who enjoys gerbes and category theory and tries to reveal their role in string theory
• Niklas Beisert who loves spin chains in AdS-CFT
• Raphael Bousso, the prince of holography, who was born in Israel but otherwise is connected with Bavaria

Because you will surely be able to find the information about the people yourself, let me add a few names without a description:

• Robert Helling (blog)
• Johannes Walcher
• Albrecht Klemm
• Peter Mayr
• Matthias Ihl (blog)
• Ilka Brunner
• Sabine Hossenfelder (blog)
• Ingo Kirsch
• Volker Schomerus
• Matthias Staudacher
• Anke Knauf
• Christian Römelsberger
• Jan Louis

I invite everyone to add other names in the comment section.

You might agree that there exists no physical law that would prevent German physics from regaining a leading role in theoretical physics, especially after the center of the world's experimental particle physics moves to CERN in Switzerland once the LHC gets started in 2007. But we should first try to understand why the American science has been ahead of Germany and Europe for a few decades.

Intellectual conservatism of the Central European science

In Central Europe, many of us have been educated by scholars whom we like(d) and whom we admire(d). They have been our examples and they have taught us important things. But I am sure that there will be many people especially from the younger generation who will agree that certain features of the mood and of the policies can be blamed for the fact that the European theoretical physics after the Second World War could not quite compete with its American counterpart. We may even invent names for some of the culprits:

1. the American financial attractor that has caused some brain drain
2. the working American free market of ideas and its less viable European counterpart
3. the relative inability of European scholars to allow their younger colleagues to get further

Concerning the brain drain, it remains the case that most of the German string theorists work in the U.S. but there exist reasons to think that this factor could start to evaporate because of the changes in the funding of science and because of recent developments on the forex market - developments that have been very unfortunate as a majority of the dollar holders will probably confirm. ;-)

The second and the third culprits have not yet disappeared. The relatively weak capitalist spirit of the Central European market of ideas has its beginnings in the 19th century when certain policies took over in Germany, Austria-Hungary, and other countries. Indeed, we also know what a "Dozent" is in the countries of the former empire of Austria-Hungary. Otto von Bismarck, a de facto co-father of the European big government concept, is another villain. Let us try to caricature and exaggerate the differences between the American approach and the Central European approach.

In the American system, new ideas are actively looked for and they are appreciated, together with their happy authors. In the Central European context, it is more important to be compatible with the old ideas - let us call them "perfectly balanced ideas" - that are currently dominating the intellectual landscape and in which the old myths and pre-conceptions play a comparable role to the newest developments. This difference between the continents has many ramifications. In the idealized Central Europe, higher age is always an advantage for a scholar because the more years you spend within the system, the more you are expected to become compatible with it.

We can almost never be quite sure which ideas will turn out to be valuable in five or thirty years but people must nevertheless make some decisions at present. How do they do it? In the American context, it is clearly important for an idea to be able to impress and excite others: in the context of science, I really mean other experts. Despite the risk that a subset of the exciting breakthroughs will turn out to be nothing else than a cheap fad, the American approach has many undisputable advantages. If people are not afraid to get excited together with others, the critical mass for the research of a class of questions can be easily reached. The people in such a community have another motivation to do what they do besides their personal curiosity and/or career plans: happy feedback from other scientists.

Whenever there is a lack of cool or obviously valuable ideas in a certain scientific field, the conservative intellectual approach may turn out to be a better strategy to avoid dead ends and various kinds of general deterioration of the whole communities. You might think that in average, the conservative approach is as good as the progressive approach. But you would be wrong because the eras in which the progress is fast are more important for science than the dry eras. In these fast eras, the progressive attitude is superior.

(To avoid a confusion, I should make it clear that the adjective "progressive" in this text essentially means "right-wing" while "conservative" means "left-wing" even though some American socialists and communists are deeply confused about this question.)

The importance of the amount of interest and the potential that hides in a certain scientific work has many consequences. The value of a particular work in science can differ from the value of other contributions by orders of magnitude. This possibly huge difference is appreciated by the American approach much more than it is appreciated in Central Europe. In analogy with the general continental European egalitarianism, people as well as ideas are often viewed as a uniform fluid. Writing "some scientific work" is more important and looked for in contemporary Europe than "making thrilling discoveries" that could impress others who understand the matter and who will cite the discoverers.

The third difference between America and Central Europe that I mentioned is the insufficient desire of the Central European scholars to support their students and younger colleagues in getting further than the previous generations. A particularly bad habit is to penalize students and others for being interested in and working on new ideas. That should never happen in an ideal world. If a student understands all the required established insights, what she consistently adds to this knowledge and this list of topics underlying her future work must always be rated positively even though her teacher is too old to appreciate new ideas or a modified philosophy that accompany them. Although this comment surely applies to many scientific fields and beyond, I will naturally focus on high-energy theoretical physics and try to be very concrete.

There are tens of thousands of Peter Woits in Europe. I mean people who are not really curious and who actually wish the progress in science to be non-existent. And even when the progress is substantial, these people will try to pretend that it does not exist simply because progress is a bad news for them. Tens of thousands of people who describe as "not even wrong" or at least "nicht einmal falsch" theories that they don't want to comprehend. We are talking about people who have learned something many decades ago and who want nothing else to become important because they don't want to digest new things. I mean people who don't want their students to be more successful because such a success could make them jealous - and it could ignite inconvenient comments from others because they are not able or willing to partially take credit for the successes of their younger peers. People who have no alternatives to the proposed theories and no other genuinely interesting ideas for that matter. People who like to discourage others. People who are much better in discouraging others than in making positive contributions. The only feature that has made Peter Woit special and semi-famous is that these uninteresting and generic personal characteristics and more or less worthless writings for crackpots and for sourballs have been combined with the cool American technology of blogging.

Summary

Let me summarize. The current relatively dry era in particle physics and theoretical physics will surely end at some time. Germany may re-gain an important role in pure science if its advantages are going to be combined with the known virtues of the spirit of America and if the "Woitian" bad mood is going to be avoided. Werner Heisenberg and Wolfgang Pauli used to have a very different approach and Pauli himself would certainly say that Woit's critical comments are "nicht einmal falsch". Very much the same remarks hold for the rest of Europe and other sciences and not only sciences.

From strings to LHC

The Tata Institute of Fundamental Research, Mumbai, India is organising a meeting

FROM STRINGS TO LHC
at the International Centre, Goa

from 2nd Jan 2007 to 10th Jan 2007.

In this meeting, we are interested in bringing together string theorists and high-energy phenomenologists and hope to give this alliance a concrete shape. This alliance is particularly valuable in light of the experimental information that LHC will provide us very soon and which we hope will tell us about physics beyond the Standard Model.

Tentatively, we have planned a few overview lectures on the first day, three days of pedagogical mini-courses on various subjects and then three days of working group sessions.

For details check:

• http://theory.tifr.res.in/~stringslhc

From the Organisers:

• Rohini Godbole
• Sunil Mukhi
• K. Sridhar
• Sandip Trivedi

Climate science in the House and Democrats

Guido has pointed out a recent TechCentralStation's article

• Science in the house of pain

about some "obtuse" Democratic representatives, as Guido puts it. The article includes excerpts from the recent hearing with the climate scientists - such as Gerry North who led the NAS panel - and statisticians - such as Edward Wegman, the author of the recent report showing that most climate scientists are crackpots in statistics.

After I read the comments by Ms. Jan Schakowsky, Ms. Tammy Baldwin, Mr. Bart Stupak, Mr. Jay Inslee and others, you may guess that my reaction would be slightly more violent than Guido's reaction or Prof. Hans von Storch's reaction - but I will ask you to try to imagine what I would say if I had to say something about it. But Hans von Storch is actually not that far from what I would say Ms. Schakowsky.

Note that I am politically correct, so my list of obtuse representatives included two women and two men - even though, I admit, the women were dumber, especially the first one.

Incidentally, Jay Inslee also thinks that theories of gravity should no longer be debated, apparently because he is ignorant of string theory as Duane Freese pointed out. ;-)

Stueckelberg Z prime at the LHC

In the last two days, some intelligent media have paid attention to the paper by

• Daniel Feldman, Zuowei Liu, Pran Nath

about the possible detection of the Z' particles that obtain masses via the Stueckelberg mechanism i.e. from an additional U(1) without any new Higgs mechanism. These particles appear as very narrow resonances and are naturally predicted by many string vacua.

See physorg.com, news.google.com.

Gabriel Agbasi demands Nobel prize

Well, some people are self-confident enough. We wish Gabriel Agbasi a lot of good luck. He will hopefully need it. ;-) His letter to the Nobel foundation is attached under his photograph. But let us start with a link.

Update: If you're fascinated by this Gentleman and author of "Ueber Alles", you should definitely read his own explanation of some events that brought him to the police station, jail, etc. because he studied in the library. If his presentation of the story is correct, The Reference Frame is leaning to his side in this particular controversy. But indeed, our support is partly based on the fact that Agbasi is a kind of right-winger.



Date: Tue, 25 Jul 2006 16:32:35 +0100
From: PHYSICS NOW
To: [All physicists at Harvard and probably the rest of the world]
Subject: (COURTESY EMAIL) Submission to the Nobel Prize Committee of the Scientific Discovery of the 4th Dimension

Gabriel Agbasi
PO BOX 3192
Bellingham, WA 98227-3192
360-603-9519

The Nobel Foundation
Sturegatan 14
Box 5232
SE-102 45 Stockholm
Sweden
Tel +46 8 663 09 20
Fax +46 8 660 38 47

July 6, 2006

RE: Submission of formal presentation to the Nobel Prize Committee of the Scientific Discovery of the 4th Dimension

To Whom It May Concern

Dear Sir/Madam,

I am a Physicist (BS 1995), a student at WESTERN WASHINGTON UNIVERSITY and I have made an important scientific discovery - The 4th Dimension. I will not get into scientific details, but a lot of our science will improve with the acceptance and use of this new discovery.

I have created a website to explain my discovery, it is titled: "Ueber Alles - The Struggle of Kurt Schwierige" - It reads like a movie, but I use this teaching technique so complex ideas can be understood with ease. It illustrates how to use The 4th Dimension scientifically.

The website address that has a list of all my Technical Papers is here:

http://www.ueberalles.com/dedication.html

The list is as follows.

(1) New Ideas in Relativity [ For Nobel Consideration ] [ Physics ]

(2) PI made Rational [ For Nobel Consideration ] [ Physics / Mathematics ]

(3) Game Theory [ Computer Systems Engineering / Machine Science / Computer Science / Neuroscience / Physics / Mathematics / 4D-Space Theory ]

(4) Machine Science [ Computer Science / Neuroscience / Computer Systems Engineering ]

(5) Machine Programming [ Computer Systems Engineering / Machine Science / Computer Science / Neuroscience / Physics / Mathematics / Music / Psychology ]

(6) 4D-Space Games [ Video Games played via "thought" : Virtual Reality Video Games Made Real... Computer Systems Engineering / Machine Science / Computer Science / Neuroscience : "Play With The Future, Today." ]

(7) Reflection, Light & Properties of "The Invisible" [ Physics & Engineering ]

(8) Grid Computing, Virtual Machines & Internet Inefficiency [ Computer Science ]

(9) The Unified Field Theory [ For Nobel Consideration ] [ Physics ]

(10) The Operating System of Organic Machines [ Computer Systems Engineering / Machine Science / Computer Science / Neuroscience / Physics / Mathematics / 4D Space Theory ]

Your committee deals with scientists and with this dimension, errors in scientific work are immediately recognized; so The 4th Dimension acts as an error checker and will become an invaluable tool for scientists to use.

I present to your committee my website, for your perusal.

Thank You.

Gabriel Agbasi, Physicist
The Author of Ueber Alles

Copy: The Royal Swedish Academy of Sciences

Resumming non-renormalizable theories?

John G. has asked me what I think about the following paper by B.F.L. Ward:

• hep-ph/0607198

This paper claims to have found a technique to resum the loop diagrams of general relativity and potentially all other renormalizable as well as non-renormalizable theories and to calculate UV finite results.

Of course that with all my respect to the author, I think that all such attempts are most likely wrong. There exists one general and essential question that all the authors of such papers - much like all researchers in loop quantum gravity and Lee Smolin in particular - seem to misunderstand. The real problem is not to obtain finite results; the real problem is to obtain results that do not depend on infinitely many unknown parameters.

Loop quantum gravity is another framework that is often claimed to be "finite" because it has a minimal distance scale. In terminology of the people who were taught quantum field theory in the same way as I was, it is not a finite theory. Instead, it is a theory with a cutoff. A finite theory is a theory that does not depend on the regulator. In other words, loop quantum gravity, Ward's paper, as well as dozens of similar attempts are just proposing another regularization and another set of conventions.

We have many other ways to regulate UV divergent integrals - such as a sharp momentum cutoff. Some other regulators such as dimensional regularization preserve some symmetries such as gauge symmetries automatically - and Ward's approach probably also cancels some unwanted diff-violating diagrams automatically. But such a regularization is not yet a way to obtain unique results from the theory.

Even if you consider terms that respect all required symmetries only, there are still many terms that can be added to the classical or effective action or that can be generated by the loops. Even if you don't read Ward's paper in detail, it seems obvious that he or she argues that a finite answer can be obtained even if you include more complicated interactions. And that's the problem because these coupling constants are not known.

If you consider a classical or an effective action in GR, there can be higher-derivative terms such as "R^2" where "R" is the Riemann tensor, with various contractions of the indices. All their coefficients are a priori undetermined. The loop diagrams generate infinite contributions to these coefficients in the effective action. But that's not the real problem. The infinite parts can be subtracted by a counterterm. The real problem is that the remaining finite value of the coefficient is unknown. Equivalently, the actual problem is that you can add higher-derivative terms with finite coefficients to the classical action and obtain an equally consistent theory that must be treated as equally plausible according to Gell-Mann's totalitarian principle.

In renornalizable theories, the finite piece of a coupling constant such as the fine-structure constant can be determined experimentally. The values of the remaining - irrelevant - coefficients can be naturally set to zero (or small calculable values) from the requirement that the quantum field theory remains valid at very high energy scales.

But such a treatment is impossible in non-renormalizable theories such as the Fermi theory or general relativity. These theories break above the weak scale or above the Planck scale, respectively. They break down even if you include the simplest interactions only. Because of this fact, you are forced to consider all other interaction terms that break down at the same scale. And there are infinitely many.

You might choose one particular set of values of the infinitely many coefficients because they look "nicer" and "simpler" on paper. But looking "nicer" or "simpler" on paper is not a physically motivated criterion, unlike the validity of renormalizable theories at very high energy scales. There is no physical reason to argue that one set of values of the coefficients of the non-renormalizable interactions is better than others. You are still choosing a random point in an infinite-dimensional space and the only question is whether you realize this fact.

Because the author clearly seems to disagree with these points - to put it very democratically - that are viewed as the standard material of courses such as Quantum Field Theory II by others, it is extremely difficult to read his or her paper for me. It just seems so manifestly wrong that it is probably a waste of time.

But on the other hand, I can imagine that there exist some valid and general insights about the loop structure of general relativity, after all. String theory does predict a particular form of the higher-derivative terms in the effective action. I tend to believe that if you look at n-derivative terms in the effective action, some of their features will be general because these very high dimension operators could be related to black hole physics: the black hole creation at trans-Planckian scattering and black hole evaporation.

For example, in M-theory, I only expect "c_k . R^(3k+1)" terms to appear in the effective action, and the coefficients "c_k" for large values of "k" should have a characteristic behavior - a function of "k factorial" or something like that - much like the stringy amplitudes have a characteristic very-high-genus behavior. Anyone knows a more detailed answer?

At any rate, I don't believe that such questions can be answered by a paper whose author seems to deny what the real problem actually is.

Unitarity

S.R. has argued that unitarity is very constraining and a finite unitary S-matrix is hard and would be interesting. I agree - and think that all unitary finite completions of the low-energy gravitational S-matrix must follow from string theory - but experience suggests that all approaches with a "universal" treatment of UV problems are non-unitary.

Recall another example of this sort: if you can add a "PHI.box^2.PHI" term into your Klein-Gordon theory (and analogous terms to other theories), it seemingly makes the propagator diminish as "1/p^4" at high energies. Such an improved behavior makes the loop diagram converge more rapidly. However, this theory is not unitary because with the extra four-derivative term, the theory is equivalent to another theory with two scalar fields one of which has a wrong sign of the kinetic term (ghost).

The fourth power is a rather simple candidate for a cure. More generic recipes to make a sum finite probably have singularities with wrong residues, too. Because this question is not discussed in the paper at all, I suppose that there is no reason why only poles with the right sign of the residues appear. The method leads to ghosts and is not unitary.

Also, I am convinced that any unitary theory that reduces to GR at the classical level must confirm the existence of black holes in high-energy scattering due to the unitarity. Because the high-energy behavior in the present paper looks different than expected from the black hole production, the obtained amplitudes can't be unitary. It is the black hole microstates that become relevant at the same energy scale where the divergent graphs become important - the trans-Planckian regime - and any paper that tries to deny this fact is fundamentally flawed.

New degrees of freedom as seen in string theory are not a "mathematical artifact" as the author seems to suggest but objects that are necessary for a smooth behavior of the full theory including gravity at the quantum level much like the W-bosons are needed to make sense out of the four-fermion theory and a Higgs-like pole is needed to restore the unitarity of the WW scattering. In weakly coupled string theory, the lightest such new objects are excited strings. These new states become progenitors of black holes if you increase the string coupling. At a generic coupling - for example in M-theory - the new degrees of freedom (new "quantum fields") correspond to black hole microstates. In all cases, these objects lead to new non-analyticities of the S-matrix.

These objects are real and attempts to live without them are as flawed as attempts to describe weak interactions at all scales without W-bosons.

Essentials of life

The world around us is a remarkable structure, despite all of its annoying substructures such as hypocricy, bureaucracy, environmental advocacy; communism, Nazism, feminism, terrorism, alarmism, NGOism; insanity, loop quantum gravity, pity; regulation, explosion, Californication; IRS, INS, HIV, AIDS, NOW, PC, NSDAP; silliness, laziness, and the Loch Ness monster.

What are the most general features of the natural laws and the environment that are required for the existence of worlds that qualitatively resemble ours? The entries below may look too constraining to some readers and too vague to others but a working draft may turn out to be useful anyway. In each case, I will try to explain why the feature is important and whether we understand its origin.

One time

The world is interesting because many things happen in it. The important processes that will be discussed below take place in this Cosmos. The future may support more organized structures than the past. Something that looks like a time coordinate is necessary. We can also see that this kind of a world requires one time coordinate and not more. If you have (at least) two large time coordinates t1,t2, then you can continuously change the direction of worldlines in the t1-t2 plane. This means that there can't exist any sharp differences between the past and the future.

In perturbative string theory, we naturally predict the spacetime to have one time coordinate from the requirement that the physical Hilbert space is positively definite - a requirement discussed in the following paragraph. The Virasoro algebra is as large as we need to decouple negative-norm states arising from one set of time-like oscillators (and another set of longitudinal i.e. spacelike oscillators dies at the same moment). Similar arguments hold in all approaches to physics that admit the light-cone gauge.

Postulates of quantum mechanics

Although quantum mechanics was born less than 100 years ago, I think it is fair to say that the basic principles of quantum mechanics are probably necessary for life, too. By basic principles, I mean the existence of a complex Hilbert space that encodes possible states of the Universe, the existence of Hermitean linear operators on this space that represent real observables that can physically distinguish different states and/or are responsible for their evolution, and the procedure to calculate probabilities of different outcomes of a sequence of events as squared absolute values of certain complex amplitudes. The last postulate requires the Hilbert space to be equipped with a positively definite norm because negative probabilities make no sense even at the logical level. The evolution operators should be unitary in order for the total probability to be preserved.

Quantum mechanics is needed in order to create sharply separated discrete states - such as the bases of DNA discussed below - in a continuous world: I am talking about discrete energy eigenstates. It is also necessary for allowing some rather unlikely processes such as quantum tunnelling. In a classical world, different possibilities would be connected by a continuum, the existence of discrete and binary codes such as the DNA code or binary computers would be extremely problematic, and small effects would always modify the uncorrected process by small amounts rather than allowing qualitatively different processes with small probabilities. Burning of stars, the transistor effect, and many other things would be at risk. Of course, in a canonical classical world that is easy to write down, the atoms would be unstable which would have truly catastrophic consequences, but even if you tried to design a more stable set of classical laws, for example by replacing point-like electrons by solid balls, I guess that life would not start in such a world.

According to the state-of-the-art picture of physical reality, the postulates of quantum mechanics as described above are exact. It seems hard to modify them or deform them and they don't need to be modified even if we want to describe processes that are seemingly as incompatible with quantum mechanics as black hole evaporation. As far as we can say, the postulates of quantum mechanics need to be imposed at the very beginning. String theory wouldn't have most of its cool properties such as dualities without quantum mechanics, but at present, quantum mechanics itself can't be derived from a deeper principle. Many leading string theorists believe that the quantum postulates will be "unified" with other features of the real world such as the geometry of various spaces (configuration spaces, phase spaces, moduli spaces, spacetime) in the future which could make quantum mechanics look much more inevitable than today.

Enough spacetime for complicated structures

One of the general features of our Universe is that it is somewhat large. There are many animals and people living on our planet that orbits one star among tens of billions in a galaxy that is just one galaxy among tens of billions. You need about billions of bits to store the information from this blog and about 10^{100} of quantum bits to store the less important information about the rest of the Universe.

Evolution needed a lot of space and time to go through and there probably exist fundamental reasons why the complex processes could not have been too much faster. At the beginning, I wrote that time was essential and you could have asked why I didn't mention space. Yes, it was because I think that from a non-physics perspective, space that approximately follows the rules of the Euclidean geometry is less essential. Nevertheless, now we see that we need a lot of room where the information may be stored. If you have a lot of "room", it does not have to be organized according to the rules of Euclidean geometry. But the Euclidean geometry is certainly a natural choice. If you want to be more specific, life like ours requires 3+1 dimensions. But theoretical physicists would certainly not count a theory as "physically inconsistent" just because the dimension of its spacetime differs from 3+1.

At the end of the whole article, I will also argue that a symmetry between space and time is needed for some aspects of life.

How can we explain that the world is large? Where do the large numbers such as 10^{90} encoding the number of particles in the Cosmos come from? The best explanation we have is inflationary cosmology. Even if you start with a Planckian universe where all quantities are of order one, inflation can lead to a dramatic, exponential increase of the total volume and the total mass of the Universe: the energy density of the vacuum is essentially constant during the inflation while the volume expands exponentially. Many quantities of this kind can naturally be calculated as exponentials of numbers that are expected to be of order 10 or 100. Although we cannot yet calculate the exact number of e-foldings from the first principles, it is clear that the mystery why the Universe is so huge significantly diminishes once we appreciate the power of inflation. Inflation simultaneously explains many other mysteries that are potentially necessary for decent life such as the flatness and isotropy of the Cosmos.

Needless to say, a large spacetime in the era of thriving life also depends on a small value of the cosmological constant. We don't have a satisfactory explanation why it's so small. In other cases, I would be ready to accept the anthropic explanation of some principles of our world because these principles are qualitative ones - for example, the existence of one time coordinate or the validity of the quantum postulates. It is much harder for me to accept an anthropic explanation for quantitative features of reality.

Hierarchies and large dimensionless numbers

Inflation has allowed us to calculate some mysteriously large numbers as exponentials of more reasonable numbers which reduced the degree of mystery hiding in many numbers of that kind. However, there are other large universal constants that have not yet been explained by this exponential mechanism or a similar mechanism. One of them is the ratio of the Planck mass and the proton mass - the kind of number that governs the size of neutron stars (and perhaps other stars, too).

If evolution needs a lot of space and time, the stars that are naturally created and that must pump energy into this whole process must be large enough. Their size is dictated by various hierarchies. The ratio between the Planck scale and the QCD scale is a key player that helps to determine the size of some stars. The huge size of this particular ratio is understood, too. It's because the QCD scale is defined as the scale where the QCD coupling is of order one. It's plausible that the QCD coupling at the Planck scale is a reasonable number such as 1/25, and because this coupling only depends on the logarithm of the energy scale, we must go to very low energy scales to change 1/25 to 1. This is why the QCD scale is so much lower than the Planck scale. This is why the protons are so much lighter than the Planck mass i.e. why their gravitational interaction is so much weaker than other interactions between them. This is one of the conditions for evolution to have enough spacetime to go. Again, you see another example of an exponential explanation of a large constant.

In the previous paragraph, I was comparing the strong force with the force of gravity. The qualitative explanation of their difference exists. However, if we compare the electroweak interactions with gravity, we don't quite know where the huge ratio between their strengths comes from - not even qualitatively. This is called the hierarchy problem. Supersymmetry helps to make this problem less serious and the smallness of the weak scale more natural and more stable against corrections - but no one has found a sketch of a convincing calculation that would describe the ratio of the weak scale and the Planck scale as the exponential of a more reasonable number. If you were able to show that the weak scale and the QCD scale must be close to each other, it could also become a solution.

There exist other large dimensionless numbers in the real world that are important for life. The proton-electron mass ratio, about 1836.15, must be large in order for the nuclei to behave classically, while electrons determine the effective interactions between them. The fine structure constant is about 1/137.036. Its smallness is necessary not only for the impressive quantitative success of perturbative QED, but it is also needed for non-relativistic physics to be a good approximation for the physics of atoms because the speed of electrons in atoms divided by the speed of light is controlled by the fine structure constant.

Nowadays, all parameters of the natural laws we use to describe the world are reduced to 30 or so parameters of the Standard Model (with neutrino masses) expressed in the Planck units, and to the cosmological constant. The tiny cosmological constant is not really understood. Some patterns in the Standard Model parameters are qualitatively understood. For example, the neutrino masses are roughly where they are because of the see-saw mechanism, assuming that a relevant scale like a GUT scale exists. Other constants have potential quantitative explanations – such as one relation between the three gauge couplings that can be deduced from grand unification. The hierarchy between the Planck scale and the Higgs vev (weak scale) is not understood too well, much like the large ratios between the different Yukawa couplings. However, the top quark Yukawa coupling may have a semi-quantitative explanation, much like some relations between the bottom quark and tau lepton couplings. Some mysteries seem less serious than others, some large parameters seem to be more necessary for anthropic considerations than others, and so on - a typical example of chaos that is still waiting for a better explanation.

Causality and locality, at least approximate ones

When I mentioned that a time coordinate was needed, I implicitly required that this time coordinate gives us an ordering that can separate the past from the future by the present. The logic of our world is based on the past that can influence the future, but not the other way around. Using a more careful quantum language, the knowledge of the data from the past is used to predict the probabilities of different outcomes in the future, but I am convinced that you should never use these procedures backwards unless you become capable to account for the fact that the entropy in the past should be lower than today which is dictated by another principle, a low-entropy beginning of the Universe. This asymmetric relation between the past and the future is what we call "causality".

We also mentioned that the Universe should be large. For structures and ideas to be developed independently and to have a value that can approximately be separated from the rest of the world, the phenomena should occur locally, without too high an influence of the rest of the Universe. The most natural way to achieve this goal is to impose a strict locality: a signal can only get from A to C if it occurs somewhere in between, in B, before it reaches C. At the end of the article, I will also discuss that the principle of relativity may be needed for life in general. String theory predicts that the rules of special relativity are always respected locally in spacetime. Special relativity strengthens the constraints of causality - you are not only unable to influence your future but you can't influence spacelike-separated events in spacetime either. In fact, locality and causality become more or less synonyma in the relativistic context.

Although one could perhaps imagine more general schemes where life would be possible and locality and causality would be just an approximation, string theory and observations seem to agree about a rather strong way to satisfy these constraints: local physics is Lorentz-invariant and satisfies the laws of special relativity.

The existence of classical limits

While some important processes in the world have a quantum-mechanical essence, it is fair to say that an overwhelming portion of the key processes in the Cosmos can be interpreted using the language of classical physics, at least if you don't care about the detailed microscopic origin of these phenomena. The functions of a classical computer, human brain, or DNA reproduction probably belong to the classical realm: the decoherence time in all these cases is much shorter than the typical timescales at which these processes occur which is why the classical intuition is justified.

The existence of justifiable classical limits is therefore guaranteed by a sufficiently large environment and sufficiently strong interactions with the environment. Once again, these things are large because the number of atoms in the brain and similar numbers are large. In this sense, the previous points about the existence of large numbers also explain why there must inevitably exist processes that admit a classical description. The very same large parameters also explain why thermodynamics is a good approximation, and so forth. There is a lot of relationships between these principles although they could seem independent a priori.

Nearly permanent sources of usable energy

Everyone knows that the energy needed for the terrestrial life comes from the Sun's thermonuclear energy after all. It's a system of processes that clearly work and no sane person can argue otherwise. A question is whether very different alternatives are plausible.

I am not so sure. The energy from the Sun is modulated by various oscillating patterns at several timescales. It's a good driving force for many interesting events. You can hide from the Sun if you need to. The biosphere is getting about 1 part per million of energy from geothermal sources. Indeed, you could design planets where this fraction would become higher. Some people have argued that the life on such planets would not require any stars. I am not quite certain. Both answers seem plausible to me.

The large stars arise if the hierarchies explained above exist and if other parameters such as the cosmological constant belong to a certain window. Because this topic is often discussed in the anthropic context, I won't repeat these considerations here.

Large enough environment to get rid of entropy

Life leads to an evolution and creation of more organized structures. In some sense, more organized structures carry smaller entropy than the organized ones. A decrease of the total entropy would violate the second law of thermodynamics. In reality, of course, the decrease of the entropy of an animal is overcompensated by the increase of the entropy of its environment. There must exist a sufficiently large environment that acts as a dumping ground for the entropy generated by life. Indeed, the Earth and perhaps the Universe are large enough for us to throw our entropy away. The environmentalist simpletons could call this emission of entropy away from the biosphere a pollution, just like they do so in the case of carbon dioxide. They call it pollution; we call it life.

There are other processes involving entropy that may be needed for life. Non-gravitational physical systems typically maximize the entropy if they become completely uniform (like a purple gas). Gravity can change the rules of the game and clumped objects can actually carry a higher entropy and become natural final states of many processes. Black holes in particular carry the maximum entropy you can squeeze into a given volume. This feature of gravity was necessary for structure formation during the childhood of our Cosmos, and I recommend you Brian Greene's "The Fabric of the Cosmos" for additional words about this interesting semi-philosophical topic.

Metastable carriers of information

Animals, plants, as well as computers need to sharply define the message they represent. They do so in the form of DNA codes or computer files. Some of these structures must occur naturally – so let us start with the DNA molecules. The information is encoded in the A/C/G/T(U) bases. If the sharp and discrete information were impossible, everything would be vague and fuzzy. Everything could continuously collapse to one particular configuration - a ground state. However, physical systems in the real world admit discrete states - for example discrete bound states that are energy eigenstates.

Mechanisms to xerox bits of information

A DNA molecule carries a message - a piece of life that wants to spread. A necessary ingredient for life to spread is a procedure that can copy bits of information. Because of the quantum xerox no-go theorem, these bits must always be classical bits and the mechanisms must fit into the framework of classical physics. As you know, the DNA molecule is a double helix or a sequence of pairs of complementary bases. When it splits into the two strands, new bases absorbed from the environment replace the old members of the pairs and two copies of the original DNA appear. The mechanisms that copy bits in classical computers differ substantially but in both cases, copying of classical information is a must. The life before DNA - with RNA or protein folding only - was probably not able to lead to intelligent, complex life because of some rather general constraints but some experts in biology will correct me if I am wrong.

At any rate, the existence of these processes in biology and computation can be demonstrated in a simple non-relativistic quantum mechanical description of these systems. The presence of the relevant ingredients is a rather generic consequence of constraints from other sections of this article.

The reproduction of the information is guaranteed to be imperfect in the real world – and this imperfection and mutations are in fact necessary for the whole process of evolution to work. The technically difficult part of the physical processes is the task for Nature to make the processes reliable enough. Making them a bit unreliable is almost never a difficult problem.

Processes that depend on the information and evaluate it

Classical computers can behave according to a program encoded in the memory. In the same way, cells are able to produce proteins if they interpret the DNA. The protein production can be viewed as a translation from the binary discrete world of the DNA codes to a more continuous world of mechanics and macroscopic biology. Computers often come with analogous devices that can translate a binary code to a physical object embedded in the continuous world.

Framework for natural selection

These physical objects - proteins or pictures printed on your printer - then behave according to more general, continuous laws of physics. Different programs, DNA codes - or scientific theories, for that matter - fight for the room under the Sun. Their interaction with the real world and with each other acts as a method to evaluate the value of the original algorithms, memes, genes, or DNA codes - and the fittest statistically survive more often than the less fit ones. This mechanism leads to progress and the evolution of more viable life forms. In the context of scientific theories, "more viable" should really mean "more true" and it does if the scientific methods to evaluate ideas are "artifically" inserted instead of the fights between the animals and other life forms. Everyone should know how evolution works because of a combination of the key mechanisms above. Completely analogous mechanisms are at work when better ideas are being developed in science or better products, technologies or policies to regulate the society are being looked for by the humans.

Once again, the microscopic realization of the basic steps differs substantially if we study different systems that are able to improve themselves. However, some counterpart of these assumptions is needed in all cases.

Less general and more technical requirements:

The principle of relativity

Theories that are normally considered in the context of modern theoretical high-energy physics are relativistic theories: they respect the laws of special relativity. In perturbative string theory, short distance physics automatically respects the Lorentz invariance because nonlinear sigma-models, when expanded at very short distances, always resemble the Polyakov action in which the symmetry between all spacetime coordinates (scalar fields on the worldsheet) is manifest. Open strings can break the Lorentz symmetry spontaneously by introducing a non-commutativity. But at some fundamental level, the Lorentz symmetry still holds. And these conclusions are probably true non-perturbatively, too. I certainly think that string theory predicts that special relativity will be verified successfully with ever greater accuracy - except for phenomena that result from well-understood properties of the environment. String theory predicts that similar violations of well-motivated principles, violations that are predicted by not-so-consistent alternatives, will remain absent well beyond the level at which they have been verified as of today.

Is the principle of relativity necessary for life? I would tend to answer Yes, it is. Our planet is moving within the Solar system and the Solar system is moving within the Milky Way. Our Galaxy is in motion with respect to the cosmic microwave background, too. These nonzero velocities are more or less inevitable consequences of the violent history of our world that was necessary for the creation of life, too. We expect the "viability" of life structures that are selected by the natural selection to be independent of this motion at many different distance scales. Moreover, the life forms should still respect the rotational symmetry. I did not include the rotational symmetry among the essentials of life because we could hypothetically imagine a living world with a preferred direction even though it is helpful if animals can use the very same methods to move and look in all directions, but if the accurate enough rotational symmetry that remains relevant for the life forms is a condition, the previous argument shows that the principle of relativity should be another condition.

In the actual theories we use and believe, the rotational symmetry and the principle relativity are of course naturally unified in the Lorentz group. Because we are aware of no experimental evidence of a Lorentz violation, because such a violation does not seem necessary for life, and because it seems incompatible with the deepest description of the real world we have, namely string theory, I am among those who think that the Lorentz symmetry of local physics is probably an exact law of Nature. In our world, the principle of relativity is the relativistic one, with a finite speed of light; no, this sentence is not a tautology. It is certainly necessary for the life and cosmology as we know it but I don't know whether you could construct life in a non-relativistic world. At any rate, if you believe that special relativity and quantum mechanics from the beginning are conditions, it also means that the world should obey the rules of quantum field theory at long distances because quantum field theory follows from quantum mechanics and special relativity.

In combination with the requirement of gravity below, we can also deduce that string theory is needed for life even though we can’t yet offer a proof that every honest person with IQ above 100 would have to accept immediately.

The existence of fermions (and atoms)

The most obvious observation that makes fermions, particles that obey the Pauli exclusion principle, essential for life is the diversity of atoms. Chemistry as we know it is based on a table of elements with very different properties. Some of the qualitative properties are a quasiperiodic function of the atomic number. As you know, this is only possible because at most one electron can occupy a state with all quantum numbers fixed. The existence of fermions is probably important for other aspects of life, too. In the context of string theory, fermions are one of the reasons not to take bosonic string theory seriously. In other words, fermions force us to consider superstring theory that has other virtues such as the absence of bulk tachyons, a necessary condition for the perturbative stability of the vacuum. In the presence of fermions, supersymmetry is a natural extension of the well-established symmetries of spacetime. Some people feel certain that supersymmetry strictly below the Planck scale - and probably close to the electroweak scale - is an inevitable prediction of string theory for the real world. Others disagree.

The existence of a universally attractive force (gravity)

As mentioned previously, gravity has the ability to clump matter without violating the second law of thermodynamics that normally drives systems (such as gases) towards uniformity. It is related to the fact that gravity is universally attractive because it is sourced by a positively definite quantity, namely the mass. Forces with both signs such as electromagnetism tend to create neutral systems such as atoms. The leading force vanishes between neutral systems. This "neutral" outcome is even more obvious for confining forces such as the strong force because charged (colored) systems are completely unphysical and cannot appear in separation. It seems that a force similar to gravity must survive after the "neutralization" time scale if we still want planets that orbit around their stars at a fair distance. Needless to say, gravity in the very narrow sense - a spin 2 force that respects the diffeomorphism gauge symmetry at low energies - is an undeniable prediction of string theory.

The existence of a U(1) gauge field at low energies (electromagnetism)

It is a disputable technical feature of the real world. Nevertheless, life similar to the life we know requires at least one unbroken U(1) at low energies. Ions with both signs of their electric charge seem to be essential building blocks for many compounds and the key players in processes in chemistry and biochemistry. Electromagnetism controls virtually everything we know about life and technology and it is of course very hard to imagine a world without electromagnetism. Although I have no complete proof, my prejudice is that the world whose only force is the SU(3) Yang-Mills interaction of QCD could not produce intelligent life. One problem of such a world would be that animals could not see – photons and arbitrarily soft photons in particular are important to transfer information without paying huge amounts of energy.

The existence of hierarchies, the Born-Oppenheimer approximation, and many "nuclei" (strong force)

At the beginning, I mentioned the importance of large dimensionless numbers that allow the world to be large and complex. One of the minor examples was the proton-electron mass ratio that allows the motion of nuclei to be interpreted classically, as the Born-Oppenheimer approximation suggests. But do we need the nuclei at all? We have mentioned that different atoms were needed which required the Pauli exclusion principle. This principle controlled the electrons. But frankly speaking, electrons are not enough. You want the atoms to be neutral. There must exist something like the nuclei that can have many values of the charge. If we want to avoid the introduction of new special parameters for each nucleus, the structure of the nuclei should be governed by more fundamental microscopic laws of physics. The laws we know from our world are described by QCD and I am not able to imagine a working appealing theory that would allow many nuclei and atoms but avoided QCD-like physics. Again, I have no proof of a no-go theorem.

Summary

As you can see, many features of particle physics did not appear in the lists above. It is fair to say that I am not aware of any truly solid arguments that the existence of some life requires entities such as weak interactions, additional families of (heavy) quarks and leptons, CP-violation (except for baryogenesis or leptogenesis), a small CP-angle, and so forth. The apparent fact that some features are needed and some features are not is enough to convince yourself that the anthropic principle can't be the universal answer to all the questions that can't be answered at present. In other words, you have all the rights to say that the superficial successes of the principle in some cases are just coincidences.

The anthropic principle, much like this text, is a method to confirm that our world makes sense after all. But it is not a good framework for producing new predictions.

Rob Myers and Royal Society

The Royal Society of Canada has 10 people in physical sciences and Rob Myers is now one of them. Congratulations.

Memorial conference in honor of Andrew Chamblin

There will be a memorial conference in honour of Andrew Chamblin in Cambridge on Saturday 14th October. It will consist of several talks by colleagues of his as well as discussion and reminiscences of Andrew and his life and work. The website with full details of the conference and online registration is:

• DAMTP website

All colleagues and friends of Andrew's as well as others in the field interested in his work and related topics are very welcome to attend and should register their planned attendance online via the website.

Via Jo.

Feminist totalitarianism: part 387

JoAnne Hewett is transforming herself into a typical representative of the feminist totalitarian ideology. In her article, she also offers four items to "remedy the systemic bias".

1. Enhance leadership diversity in academic and scientific institutions.
2. Recognize the importance of role models and increase the diversity of faculties
3. Take the responsibility to speak out against discrimination.
4. Boost the self-confidence of girls.

That can be translated into a more honest language:

1. Further cripple the intellectual diversity of the Academia and make the life for those who are irritated by dumb feminist speeches and articles such as JoAnne's article really unbearable. Fire as many male officials as possible, especially male officials who don't accept feminism.
2. Eliminate the remaining independence of thinking in the Academia and educate a new generation of scholars who will be just parroting other scholars, especially older female scholars - the “role models”.
3. Proliferate lies about discrimination that has been working against men at least for 30 years, and criminalize all those who realize that the hypotheses about remaining substantial discrimination against women are malicious lies. Only one kind of comments may be allowed.
4. Further cripple the self-confidence of boys and more generally the self-confidence of all those who would normally matter in scholarship, and make radical feminists who prefer their political agenda over science even more vocal and more obnoxious.

I think that all of these items are outrageous and the ideology behind them is irrational and hyenic. In a recent incident, the president of Harvard University was forced to resign primarily by the defenders of the feminist ideology above and closely related ideologies. So far, Harvard has lost about $390 million in donations although the moral and intellectual consequences are far more serious.

People like JoAnne Hewett have been effectively controlling the Academia at least for 30 years and their power goes far enough so that they can indirectly fire a famous university president for saying inconvenient comments behind the closed door. But they still have the stomach to paint themselves as victims.

Clearly, firing presidents and wasting of hundreds of millions of dollars on programs to discriminate against boys is not enough for them. What can be done to really satisfy them? Maybe those who think that the ideology about the equal aptitudes of men and women is crap should be sent to gas chambers? Perhaps those who don't want to codify 50% quota for women should join them, too?

It's a rather solid result of neurobiology and other fields - disciplines that Hewett and others would immediately ban if they could - that both the anatomy as well as physiology of female and male brains differ substantially and these differences are magnified if extreme abilities of certain sorts are required. These differences can be observed by a rich variety of methods and they can also be theoretically justified in the framework of evolution.

Women in average are very good and perhaps better with emotions, language, and two-dimensional organization of items. Men are better in three-dimensional visualization and math and engineering skills, among other things. Moreover, men have a measurably higher variance of a diverse list of quantities. The average IQ, the average number of children, and so on are all quantities that are more fluctuating in men than in women. The higher variance implies that it is easier to find more extreme men than more extreme women, regardless of the exact quantity that defines the extremality.

These facts combine in such a way that it can be predicted that for example, the number of male winners of the Fields medal exceeds the number of female winners roughly by two orders of magnitude.

JoAnne Hewett enumerates 21 female physicists who are automatically heroes because they are still discriminated against, she argues. If I wrote so many untrue assertions, I could not sleep. JoAnne Hewett has clearly no problems with her conscience.

Imagine that we would be talking about the rightwingers in physics rather than women in physics. I could not enumerate 21 rightwingers even though their proportion would "normally" be expected to be 50%, just like for women and there have existed societies in which the percentage exceeded 50 percent (unlike the case of women). Most optimistically, I could mention 2 or 3 people who are rightwingers according to some rumors or very private communication but I would not have the courage to write their names here because these guys care about their careers which makes it necessary for them to hide their political opinions.

Is there a woman who has to hide that she is a woman in order to do physics?

The political diversity is where the real discrimination lies, and people who continue to argue that women are systematically discriminated against in the Academia are not telling you the truth. On the contrary. I could also inform you about several stories how the positive discrimination works in a plethora of various committees in which I have served. It has become a substantial bias and I already know names of boys - including a gold medalist from the International Physics Olympiad - for whom the positive discrimination became an ordinary discrimination.

It's completely clear that men are already discriminated against in physical sciences. We could perhaps justify such an approach because of some social reasons unrelated to science itself. If I were justifying such policies, the first justification would be to assure that both the girls as well as the boys in physics are surrounded by some girls because it may be a psychologically healthier environment. However, no one can justify lies about the actual situation. Lies can never be expected to lead to good results.

The Jews were also painted as a group discriminating against others - or spoiling the life of others - in Germany of the 1930s, much like the capitalists were those who were painted as universally discriminating against the workers in the Eastern Europe after the Second World War. We know where these ideologies have led, and I don't see any truly qualitative differences between the three examples. In all cases, we face ideologies that reject reality as we observe it and that want to replace it by a conspiratory theory whose political goal is to substantially alter the natural structure of the society.

Evaluating extreme approaches to the theory of everything

One of the general strategies of some thinkers in theoretical physics is based on attempts to heavily extend the relevance of an existing concept or method. The hope is that all other difficult concepts become unnecessary or they will follow from a single, generalized and stretched idea. So one takes an existing procedure or a concept - a conceivably deep idea - and hopes that a more beautiful and a more powerful version of it will define and describe the whole Universe or all of string theory (or at least a much larger body of knowledge).

I will treat the "whole Universe" and "all of string theory" as synonyma because I am not aware of any controllable framework that would allow me to separate them sharply. Nevertheless, it is obvious that some of the ideas below will depend on our available knowledge of string theory more vitally than others.

One thing is clear: the principles below have almost nothing to do with the actual current research in string theory or the main ideas that drive the current research. Instead, the principles are possible speculations of string theorists as well as non-string theorists for the future. A certain Manhattan blogger has misunderstood this very basic point. It will be very difficult for him to correct his article because the critical error already appears in the title of his article. Well, the title of his blog is based on a profound ignorance, too, so it is difficult for him to write something reasonable on his whole blog.

In the bulk of this text, I will maintain a somewhat critical tone. Indeed, it is likely that all the big ideas below - or all ideas except for one - will turn out to be wrong, useless, or shallow. Even the most successful one may look as a very sketchy caricature of the truth in the future. Nevertheless, a loophole can emerge and revive one or two ideas in the list and lead to a significant progress in the future. Because the sentences so far could sound a bit abstract, the reader may look at the subtitles written in the bold face below before she decides to swallow or not to swallow the entire text.

The world is based on a local field theory after all

The effective quantum field theories have been highly successful. They are predictive because physics at low energies can be uniquely determined by a small number of parameters - the relevant and marginal couplings. Gravity does not seem to fit in this framework. Many string theorists would be happy to have a description of string theory that would make the locality in spacetime as explicit as possible (and it would probably be background-independent in the stringy sense, too) but there are many problems and no-go theorems that make such an approach difficult. The existence of a scale - the Planck scale - seems to be very important for gravity and the existence of useful fixed points seems unlikely. The Weinberg-Witten theorem makes it very rather inconceivable that the graviton can be a composite particle and that gravity can be emergent. String theory perturbatively requires infinitely many fields to be formulated as a field theory and the classification of its interactions according to the dimensions seems useless. The UV and IR physical phenomena are mixed and related in string theory which contradicts the one-way character of the renormalization group. String theory - and quantum gravity - simply seem to be different from effective field theories.

The world is determined by a gigantic global symmetry

In physics, we encounter two basic types of symmetries: global and local symmetries. Global symmetries are actual transformations that map one configuration (state) to a different configuration (state) whose physical behavior is however identical. Examples are the Lorentz group or supersymmetry in non-gravitational theories, the electric charge in descriptions of electromagnetism that are not based on gauge theory, or the approximate symmetry of isospin in the context of the strong interactions. An important difference between the global and local cases is that the physical states actually don't have to be invariant under the transformations of global symmetries. This means that the representation theory of the global groups is very important because all representations can occur in the physical spectrum. This situation profoundly differs from the case of gauge symmetries under which the physical states must be invariant: the trivial singlet representation is the only one that is directly relevant for physics.

Many people have proposed that there exists an extraordinary group G that is the global symmetry of reality and all properties of reality follow from the properties of G. What does it mean for G to be a symmetry group? Traditionally, it meant that all of its elements (and henceforth generators) commute with the Hamiltonian. In the context of special relativity or general relativity on fixed backgrounds, some symmetries - such as the boosts and their Lorentz generators - don't have to commute with the Hamiltonian. But they still generate a simple enough algebra. If we understand the term "symmetry" in this fashion, the main objection to the big idea is simply that the world does not seem to have large global symmetries beyond those that we know. The uniqueness of single-particle states with a given value of the momentum and the spin implies that there don't seem to be any additional labels associated with basis vectors of a nontrivial representation of a large unknown group G. Experimentally, all states seem to be singlets under an exotic and large enough group G. If all states transform trivially, you should better say that the symmetry does not exist unless you want to proliferate angels on tops of all needles.

In the context of string theory, we have a more conceptual argument against a large global symmetry underlying the whole world: global symmetries should not exist at all. One can prove that this is the case perturbatively: for every current of a global continuous symmetry, one can also construct a vertex operator for a corresponding gauge boson that proves that the symmetry is local. Moreover, this local character of all exact symmetries in string theory seems to hold nonperturbatively especially because all known symmetries can be related to weakly coupled perturbative symmetries by dualities, and the latter must be gauge symmetries.

There exists another way how to interpret the term "large global symmetry". It could be such a huge group or algebra that it would contain virtually all of the observables. Imagine the algebra of all operators in your theory - something that people in algebraic quantum field theory like to think about. With this understanding, you also face problems. This algebra is either completely unconstrained or it is over-constrained. The algebra of operators in a quantum field theory is not an organizational principle that can determine some physical questions that you actually want to be answered. It is at most a language to present insights that have been found by other tools. For every possible quantum field theory, there is an algebra and such an algebra is clearly not unique. We don't learn anything from such a huge algebra in which most commutators are zero. On the other hand, there are very large algebras that are much more unique - such as W_infinity algebras. Such algebras lead to strong constraints on physics. In fact, these constraints are far too strong: they typically make your theory integrable so that the interactions essentially vanish. I think that there exists no new, yet unknown intermediate case that would allow interactions but that would lead to an algebra and a theory with finitely many undetermined parameters. The Coleman-Mandula theorem and its ramifications that allow for supersymmetry seem to enumerate all possibilities.

The world is all about a gigantic gauge group

Gauge theories have been very successful. Their tools have appeared many times in the Standard Model and their fundamental character was also codified by string theory. It is natural to think that the whole world is derived from a much larger gauge group or its generalization. The first steps in this direction were made by Grand Unified Theories and a more ambitious goal would be to extend the principle to include gravity and the rest of physics, hoping that it will also become more constraining. The cubic open string field theory may be sold as an infinite extension of the principles of gauge symmetries. It has a gigantic gauge symmetry: the parameter of a transformation is a string field and the transformation acts on another string field. The Yang-Mills transformations appear as a very small subgroup. The stringy gauge transformations carry a flavor of the whole theory. In some sense, the whole theory - of interacting open strings - follows. Note that open strings don't carry gravity either: open string field theory is another non-gravitational extension of Yang-Mills theories.

Nevertheless, this approach became less promising in the last 15 years. The main reason is that we have learned that the gauge symmetries are not fundamental in physics. More precisely, a gauge symmetry associated with a particular physical system is not unique. Even in the perturbative context, we can construct the physical space of a theory such as the electroweak theory without any gauge symmetries. Nonperturbatively, the "social scientific" character of gauge symmetries is even more obvious. Because of various dualities, two systems with two different "natural" gauge symmetries may be completely equivalent. The identity of the gauge symmetry depends not only on physics but also on the classical limit around which we expand and other choices in our formalism.

The list of such dualities includes S-duality - for example the equivalence between the SO(2N+1) and USp(2N) gauge theories with N=4 supersymmetry in d=4. It also includes equivalences between non-commutative and commutative non-Abelian gauge theories. The gauge-gravity dualities are yet another example. Yang-Mills theories with many colors are equivalent to gravitational theories whose "natural" local symmetry group includes diffeomorphisms. In the context of string theory, "natural" gauge symmetries often appear and disappear. The SO(32) heterotic string theory on a circle can be Higgsed by Wilson lines down to U(1)^16 and we can move in the moduli space so that a new enhanced E8 x E8 gauge symmetry suddenly emerges. This forces us to say that the points with both unbroken gauge symmetries belong to the same theory. Neither SO(32) nor E8 x E8 can be viewed as a "more fundamental" or "master" group. In fact, both of them are rank 16 dimension 496 groups and they are surely not subgroups of one another. It is also hard to reconcile these groups by embedding both into a larger group. The only natural candidate for such a larger group is the gauge group of the corresponding string field theory whose open string version has already appeared in this text.

If we summarize, gauge symmetries seem to be a rather good description of spin 1 particles (or spin 1 and higher in string theory where the internal motion of strings can add extra spin) and they determine their interactions in the classical, weakly-coupled limit. The power of the principle of gauge symmetry seems to diminish in the very quantum, strongly-coupled regime. The interactions of fields with spin below 1 seems to be undetermined. Moreover, different classical limits of the same quantum theory - those related by dualities - typically have different or very different gauge symmetries. In the context of string theory, large gauge symmetries appear in the language of string field theory. These large symmetries are generated by the conformal symmetry on the worldsheet whose range of validity is perturbative once again. The precise realization of the string field gauge transformations is not unique and their classification is as difficult as a classification of conformal field theories. This is enough to see that the "grand principle" of a large gauge symmetry won't tell us much more than what we already know.

The world is the cohomology of a master operator

This paradigm is closely related to the previous one because the BRST operator can be interpreted both as the exterior derivative on a generalized "master manifold" as well as a BRST operator imposing a gauge symmetry. It is necessary to say that some people exaggerate the fundamental character of BRST operators. They're a trick to deal with gauge symmetries at the quantum level. You can always present any physical Hilbert space as a cohomology of a BRST operator - for example as the cohomology of the "Q=0" operator. Note that all states are annihilated by Q and no non-trivial states are of the form "Q lambda". Talking about a BRST operator as a fundamental structure is a vacuous proposal because we just move the bulk of the question to the question What is the kinematical Hilbert space from which the BRST cohomologies are constructed and how does Q act on it?

When I mentioned cohomologies, we could also mention equivariant cohomologies and other notions. These concepts routinely occur in the research of orbifolds, D-branes on orbifolds, and other objects and many string theorists know them extremely well. Peter Woit recently wrote that equivariant cohomology should turn out to be extremely deep and far-reaching. Woit often writes the same thing about the Dirac equation: he presents himself as a confused teenager who has not yet digested the Dirac equation or equivariant cohomology and who has many irrational ideas how far-reaching these concepts could become. Meanwhile, others have studied these structures in detail: the Dirac equation has been around for 80 years. These structures have transmuted into routine parts of the research in theoretical physics and their mythical fog has largely evaporated. Peter Woit's suggestions are so vague that I think it is a waste of time to try to add the correct link to his text even though it could be another good example how the "alternatives" of string theory look like: they're about a superficial understanding of 80-year-old concepts. A superficial understanding of anything is always a good starting point for irrational religions.

The world is a huge spontaneously broken group

You could also imagine that the fundamental principle underlying the real world is a particular spontaneously broken group or an unknown confining group. These two cases may probably be treated together because confinement and Higgsing are dual to each other. Roughly speaking, confinement of a group G is equivalent to the Higgsing of its S-dual group. If you choose the language of confinement, you can see that a hypothesis about a new confining group is a hypothesis about a new substructure - one that is analogous to the parton substructure of the nucleons. You will still have to figure out what the substructure is and what the corresponding confining group is. While it is always a possibility that such a new confining symmetry waits in the heart of the matter, you should notice that until you actually say what the symmetry is, you have not made any progress. Moreover, confining groups are gauge groups after all and all of the previous criticisms of "master" gauge symmetries, especially the non-uniqueness of a gauge group for a given physical system, still hold. The hypothetical existence of new confining groups is similar to the belief of many people - starting with Vladimir Lenin - that the hierarchy of substructures of matter is infinitely long. This belief simply seems to be incompatible with quantum gravity that does not allow any structures shorter than the Planck scale.

Discrete world

I have discussed the paradigm of a discrete world many times in the past. I think that it is the preferred idea of most crackpots. It seems as en extremely shallow idea to me - one that people choose because their mathematical skills and their imagination are heavily limited rather than strong. Truly fundamental ideas cannot be discrete. Discreteness is always an emergent feature of a physical system. In the old quantum theory, discreteness was postulated but the "new" quantum mechanics has derived a more accurate version of the previous insights from a formalism based on continuous objects. Such an evolution is bound to happen in all similar situations in the future.

A discrete description of the world and its objects is nothing more than a method to divide objects and their relationships into boxes but it can never explain why the objects are what they are, and why they interact the way they interact (infinitely many undetermined parameters of the loop quantum gravity Hamiltonian represent a textbook example of the ignorance). I can offer one more framework to explain why I consider discrete physics to be junk science. Visualizing the world in terms of discrete fundamental building blocks is a sort of literary criticism. Discrete physics is a soft social science after all. Much like the feminist scholars who believe that the penis is a social construct or a creation of words, discrete physicists believe that everything in the Cosmos follows from similar words, characters, or finite mathematical structures. But this is how science has never worked and it will never work so in the future. Words, letters, and tables with discrete entries will always be just a description of physics that has existed before. Words or discrete entries may sometimes describe your perceptions but they will never explain them. You need mathematics - deep enough mathematics which means mathematics with continuous structures - to be able to answer all questions "Why".

Among all theories of a certain kind, the theories whose all building blocks are discrete span a subclass that is not more mathematically consistent than the rest. This subclass is not more predictive than a generic theory either and it has no other physically attractive features either. Discreteness is a postulate whose only virtue is that it allows mathematically challenged people and social scientists to create a skewed psychological idea how the real world looks like. I don't think that simplifying life for intellectually challenged people is the main goal of Nature.

Categories, 2-groups, 3-groups

The relation between category theory and physics has been discussed on this blog, too. One of the "positive" topics was the way how category theory is believed to be relevant for analyzing some properties of D-branes that go beyond K-theory. Category theory, the generalized abstract nonsense, may be a way to rigorously organize the concept of "analogies" and other notions that are useful for thinking in general. But it is not suited for physics exactly because it has very little to say about the continuous objects and procedures how verifiable real numbers can be predicted. After all, the characteristic picture of category theory is a combinatorial graph, a very discrete object. The non-trivial content is really hidden in the detailed properties of the nodes and links. The graph itself - and category theory as such - is as unnecessary for a physicist as a book XY whose only goal is to explain the ordering of chapters of another book UV and their relationships.

Here I want to say a few words about the gerbes and related issues. Many people have struggled with a generalization of non-Abelian gauge symmetry to the case of p-forms, something that could be relevant for the (2,0) superconformal field theory in six dimensions, among other applications. The results so far seem to be a failure to me. One should realize that there is no reason why such manipulations with symbols should generate a Lagrangian that is relevant for the (2,0) theory. Because the theory has no coupling that can be adjusted to a small value - its characteristic coupling is essentially one - there is no reason why there should exist a classical limit that could be described by a classical Lagrangian. It is not a proof that such a Lagrangian cannot exist either but it is a reason for doubts.

What I find even more discouraging is the fact that the people who believe that new papers about these gerbes and 2-groups etc. are very deep - for example, our colleagues from the String Coffee Table such as Urs Schreiber (with John Baez) - mostly ignore the actual results of string theory. I think that such an approach just can't lead to any progress even if you invest centuries and hundreds of people. We know very well, albeit indirectly, that a theory that should have physics analogous to the "gerbes" exists as a particular decoupling limit of string theory. The precise properties of such a (2,0)-like theory that can be derived from string theory are the best available tool - because we can't use experiments here - to decide which new ideas about the gerbes are good ideas and which ideas are bad. If someone chooses not to use such a tool, it is almost guaranteed that her new papers will be just new random combinations of the old symbols and there won't be any real progress. Progress in science and not only science critically depends on the tools that can separate better ideas and structures from the worse ones.

The previous paragraph also clarifies my style of reading these papers. The abstract has so far been always enough to see that these fundamental gerbes papers make no quantitative comparison with the known physics - i.e. physics of string theory - and for me, it is enough to be 99.99% certain (I apologize for this Bayesian number whose precise value has no physical meaning) that the paper won't contain new interesting physics insights. More seriously, I believe that the theories analogous to the (2,0) theory are rather rare while the authors often seem to think and claim that they can construct such theories as easily as classical gauge theories. Because I think that most of these theories can't exist, it leads me to the opinion that the whole papers must be wrong at the quantum level.

Third quantization, fourth quantization, infinitely many quantizations

Quantum field theory is often presented as a result of the second quantization in the textbooks. In reality, what we do is the ordinary first quantization applied to the classical concept of a field. However, a classical field seems to be mathematically similar to a wavefunction - the result of the first quantization in mechanics. They have a very different interpretation but they include more or less the same "amount of numbers" in them. The Maxwell field is a vector (or 2-form) field and the additional Lorentz indices slightly distinguish it from the simplest wavefunction. However, a classical string field in string field theory is described by a function or a functional of the very same variables as a first-quantized wavefunction of a string. In this sense, the term "second quantization" can be justified quite rigorously in string theory. There is also a reason to say that the last, second quantization of string field theory is actually a third quantization. It's because a classical configuration of a single classical string is already described by a function X(sigma) which approximately contains as many numbers as as a wavefunction of a particle on a line. This classical string is quantized to obtain the single string Hilbert space which is then quantized again in string field theory. You can see that there are really three quantizations going on here but it is a matter of terminology and ideology.

Every quantization creates more continuous objects. How do I measure how much continuous objects are? Discrete objects are, in some sense, zero-dimensional. The higher dimension of space you deal with, the more continuous your treatment is. You can jump to an infinite dimension to obtain "very continuous" objects: such an infinite jump is a part of the quantization procedure. The nature of "infinity" that counts the dimension may be subtle. Structures can be more infinite-dimensional than others, especially if they result from multiple quantization procedures. You could also imagine that the right description of a system is obtained by quantizing a system infinitely many times. There could also exist fixed points under the quantization "functor". The last word in the quotation marks was picked to show a relation with the previous "big ideas" based on category theory. Nevertheless, I am not aware of any way how to construct a predictive theory out of these superficially attractive concepts of multiple quantizations.

The worldvolumes are spacetimes of other string theories, and so on

The paradigm of multiple quantization is also closely related to another "big idea" that is probably the most favorite of mine in this whole list. Perturbative string theory shows that the fields in spacetime are not yet fundamental: they are described by states of a more fundamental theory that lives on the two-dimensional worldsheet. Now, the two-dimensional worldsheet is described by a two-dimensional gravitational conformal field theory. Although gravity can be more or less described by a local field theory in less than four dimensions - because it has no real physics in it - you could still argue that the right way to describe a gravitational theory should be in terms of string theory. The worldsheet should be a spacetime of another string theory. And perhaps, this step could continue infinitely many times.

That's an idea that was first clearly articulated by Michael Green around 1987. The underlying string theory was identified with one of the string theories with extended worldsheet supersymmetry - N=2 or (2,1) strings - especially in the subsequent papers backed by names such as Ooguri, Vafa, Kutasov, Martinec, and a few others. I've spent a lot of time trying to reconcile these ideas with the mysterious duality by Iqbal, Neitzke, and Vafa that relates del Pezzo surfaces and toroidal compactifications of M-theory. With the help of technically gifted colleages such as Natalia Saulina, it was eventually possible to see that some very particular schemes of mine how this whole system of ideas could work are simply impossible. The critical step was to decide whether a certain class of worldsheet theories with N=2 supersymmetry can exist or not. This is an example how people who are more experienced with a certain kind of thinking can abruptly clarify ideas that others could try to study for years. For example, if the people in loop quantum gravity suddenly decided to listen to other physicists, we could explain them in 5 minutes why their multi-decadal efforts are hopeless and why many of their big conjectures can be clearly answered "No" instead of remaining in the limbo of wishful thinking: it's enough to turn a sufficiently powerful brain on to find the correct answer "No" in a few minutes.

Unfortunately, they have not decided to listen to other physicists so far which is why they're wasting one decade after another by efforts that can clearly never lead to anything interesting. At any rate, I am virtually certain that the value of the worldsheets-for-worldsheets idea exceeds the value of all loop quantum gravities and spin foams that have ever been studied. The only reason why we hear "loop quantum gravity" more often than "worldsheets for worldsheets" is a sociological one, namely that loop quantum gravity is vocally supported by a large number of crackpots and semi-crackpots who find, because of their limited mathematical intuition, the underlying dynamics of worldvolumes in string theory as well as many other ideas far too abstract.

If we talk about the spacetime vs. worldvolume descriptions in string theory, we can ask which of them is more fundamental. In the golden era of perturbative string theory, the worldsheet was obviously more fundamental. During the duality revolution, the fundamental string has become just one type of an object that happens to be the lightest one in a certain regime, namely the weakly-coupled regime. Nonperturbatively, the strings are as fundamental or non-fundamental as the branes that look like heavy solitons. Because the strings are no longer fundamental, their worldsheets cannot be quite fundamental either. In the 1990s, the focus has returned to the spacetime. We may also say that the holographic correspondence has codified a balance between the two approaches. The boundary CFT is a worldvolume theory and it is exactly equivalent - which also means equally fundamental - as the bulk spacetime description of gravity.

Bootstrap

It is therefore not so clear whether a hierarchical picture of theories generating each other is the best picture of the scheme of things. Various descriptions of physics and the objects could be equally fundamental and their precise form could be determined by a self-contained set of conditions. Another extreme big idea in physics is that everything follows from general physical consistency requirements. This idea has been proposed many times in the past. In the context of strong interactions, bootstrap turned out to be very wrong. We know that QCD is physics of fields that are as fundamental - and describable by classical Lagrangians - as the fundamental particles of QED. Moreover, there are many consistent, asymptotically free theories analogous to QCD and the general physical consistency constraints are certainly not enough to find the correct one.

However, bootstrap was successful in the case of two-dimensional conformal field theories. Many classes of these theories have been classified and some of them have been solved.

In the context of quantum gravity, many of us more or less secretly believe another version of the bootstrap. I think that most of the real big shots in string theory are convinced that all of string theory is exactly the same thing as all consistent backgrounds of quantum gravity. By a consistent quantum theory of gravity, we mean e.g. a unitary S-matrix with some analytical conditions implied by locality or approximate locality, with gravitons in the spectrum that reproduce low-energy semiclassical general relativity, and with black hole microstates that protect the correct high-energy behavior of the scattering that can also be derived from a semi-classical description of general relativity, especially from the black hole physics.

This belief is not influencing the explicit current research much - something that a blogger from Columbia University is completely unable to understand - but it is definitely a nice and plausible idea. The main obstacle that you must overcome to transform this idea into a valuable established paradigm is a yet unknown system of mathematical proofs that the general rules of quantum gravity above - and perhaps a few more that I have missed - do imply that physics must reproduce what we know from string theory. For example, prove that there must always exist a physical process in a theory of quantum gravity as defined above that creates a large region whose local physics mimicks one of the six maximally dimensional backgrounds of string/M-theory (11 dimensions, type I, IIA, IIB, HE, HO). I think that the statement that string theory and consistent quantum gravity is the same thing is almost certainly true - 95% of certainty - and I can even imagine that someone will eventually prove it.

The universal Hamiltonian is a Laplacian on a master manifold

Let me end up with one more attractive idea. The Hamiltonian describing all interesting physics of string theory and everything else could be as simple as a Laplacian on a master manifold with very special properties. Consequently, all the partition sums could be encoded in a master function picked by some very particular constraints. The U-duality group of M-theory and modular functions are certain to play an important role. This approach was elaborated upon by Ori Ganor a few years ago, and recently by Neitzke et al. in a paper that connects this religion with more-or-less established insights by Ooguri, Strominger, and Vafa about the black hole entropy's relations to topological string theory. Again, there are some technical reasons to doubt that this approach could describe "everything". But I think that these ideas are deep enough and there is no metaphysical reason why such ideas would have to remain wild speculations with limited impact forever.

Congress on global warming

A committee of the U.S. Congress - or its Whitfield subcommittee - debates the paleoclimate reconstructions online. You can see this

• real play feed.

Edward Wegman - who voted for Al Gore in 2000 - has deconstructed the "hockey stick graph". He and others have shown why the hockey stick shape is a result of a decentering error and disappears as soon as the error is fixed. He also says that the rest of the paleoclimate community is not independent of Michael Mann who has had 43 co-authors.

Michael Mann does not find the U.S. Congress too important, and he has sent a lawyer instead.

Meanwhile, the Democrats have mostly given up Michael Mann, agreeing that his kind of science is crap, and try to argue that there exists other evidence of anthropogenic global warming although it is not 100% clear to your humble correspondent what this other evidence is supposed to be. Crowley tries to confirm the Democrats' viewpoint with boreholes etc.

Some of the Gentlemen are rather impressive guys - Wegman, North, Carl, Crowley, von Storch, and McIntyre is the full list. Hans von Storch, the former chairman of the German Society of Donald Duck, got pretty lively, and you can already see his testimony.

An extensive discussion about this program can be followed at ClimateAudit.

Prof Schwinger repairs Hewlett-Packard laptops

This text is not important but it is somewhat entertaining.

The Brazilian server Fórum PCs has an interesting article that describes an omnipresent laptop keyboard timebomb of Hewlett-Packard notebooks (English translation). The punch line of the article is a "magic URL" to a very efficient guide written by Prof. Schwinger of Harvard University that tells you what is the reason of the problem and how to fix it.

The Brazilian computer enthusiast includes two photographs in his article. Both of them are exactly identical and both of them show that Prof. Schwinger has exactly the same model of a notebook, knife, scissors, and digital camera as your humble correspondent. ;-) The Brazilian source reveals that Julian Schwinger offers a better computer support than HP itself even 12 years after his death.

Adrenaline sports

Have you ever attended a rope center, such as one in Dolní Polžice (gallery)? It's been slightly nontrivial but we have finished it. Polžice is the village where the enlightened and famous Czech 17th century aristocrat, Kryštof Harant z Polžic a Bezdružic, was born. The literal ;-) English translation of his name is

• Christopher the Bastard from After Spoons and Without Satellites

A rope center consumes more energy than a bungee-jump that we tried a couple of years ago.

Solar forcing

One of the most obvious phenomena that are important for determining the climate on the Earth is the solar activity. The Sun is important because we receive 99.998% of energy from this rather well-known star (the rest are mostly geothermal heat sources). Recall from the text

• Earth's energy balance

how those averaged 342 Watts per squared meter (one quarter of 1370 W/m^2, the solar constant) coming from the Sun are absorbed and/or reflected.

If the solar constant changes, the equilibrium temperature of the Earth changes, too. You can use the Stefan-Boltzmann law to have a rough idea about the effect. Because the heat (power) emitted by the Earth goes like

• IR emission = const T^4

where T is the temperature in Kelvins, you can see that each change of the temperature by 0.2% (around 0.6 Kelvins because we live in nearly 300 Kelvins) requires a 0.8% change of the solar constant because of the fourth power; this relation is the black body value of temperature sensitivity. 0.8 percent from 342 W/m^2 is about 3 W/m^2, way too much. In fact, we should count these 0.8 percent from the actual IR emission only, which is about 2/3 of those 342 W/m^2, more precisely 235 W/m^2. Still, you might need a change of 2 W/m^2 or so to explain the warming by 0.6 Kelvins during the 20th century.

The real "bare" change of the solar constant in the last 100 years was probably smaller, about 0.4 W/m^2. However, Nir Shaviv in

• physics/0409123 (plus a published version of that article)

proposed a mechanism, including a calculation, that attributes a very important amplifying role to the reduced cosmic ray flux. (See also astro-ph/0209252.) The reduced intensity of the cosmic rays decreases the formation of the low-level clouds (through a suppression of their condensation cores). This change allows more solar rays to reach the surface of our planet which results in warming. With this mechanism accounted for, Shaviv changes the bare estimate of 0.2 Kelvin degrees resulting from the 0.4 W/m^2 increase of the solar constant to an improved estimate of 0.4 Kelvin degrees.

The reason why I write about these mechanisms right now is that

• CO2 science

has just posted a text about the solar forcing. You should notice that the calculated increase of the temperature - written as 0.4 or 0.5 degrees, according to the exact source - is a majority or nearly all of the observed 20th century warming which was around 0.6 degrees.



Surely, some numbers will be recalculated, modified. New terms will be added and others will be ignored in the future. But the main message of this exercise is that there are definitely other terms that are likely to be as important as the greenhouse effect or even more important. It would be completely irrational to pick one particular term - the greenhouse effect of the carbon dioxide - and create new ministries responsible for this single term.

The full answer to an important question - for example, what temperatures do we expect in 2050 - has many other terms and even the sign of the sum may differ from the sign of one individual term. When you get an idea about the sign of one term in a sum, you are still pretty far from a full calculation.

In 2003, Nir Shaviv and Ján Veizer studied the effect of galactic cosmic rays on the

• Phanerozoic climate

and found that 2/3 of the changes could be attributed to the passages of the solar system through the spiral arms of the Milky Way. Assuming that the rest is attributed to carbon dioxide, they obtain 0.5 Kelvins as the likely value of the climate sensitivity, with the probability that the value exceeds 2 Kelvins being below 1%.

Some people might be interested in the citation counts: the Shaviv-Veizer paper has 38 citations right now while its main competitor,

• CO2 as the primary driver of the Phanerozoic climate

has 25 citations now, despite the heavy omnipotent bias promoting CO2. But whoever wants to have a strong opinion should actually try to read both of these papers and perhaps even the 8-citation vague and critical paper by RealClimate.ORG's Rahmstorf et al.

Previous climate science article:

• Correlation between CO2 and temperature

Bush uncensored

Noam Chomsky has recently visited the Hezbollah headquarters and offered his wholehearted support. Fortunately, Israel had a better idea what to do with these headquarters - bomb them.

Yesterday, George Bush's private comments to Tony Blair were recorded. Suddenly, you can hear Bush without the hypocricy imposed by political planning and by the pressure of various politically "correct" people.

Bush suggested that Kofi Annan is a naive guy who thinks that ceasefire is everything you need in the conflict between Israel and Hezbollah. Instead, Bush said that the U.N. should force Syria to prevent Hezbollah from doing this shit [sic].

Neither Israel nor the state of Lebanon are responsible for the current conflict.

It turned out that Condi Rice is planning a mission to the Middle East. Also, many other politicians except for Bush are talking about nothing for too long, Bush thinks and your humble correspondent certainly agrees.

Harvard loses $265 million

The losses of Harvard University related to the forced resignation of Lawrence Summers climbed to 265 million USD or, according to the Wall Street Journal, to 390 million USD. The former donors - Ellison, Rockefeller, Zuckerman, Smith - are all Summers' supporters.

Now it's up to the feminists and their allies to pay quarter a billion of dollars, the cost of their experiments so far. If there are 200 of them, each of them can pay 2 million dollars to partially clear their conscience. Meanwhile, Harvard evacuates students from Lebanon to Syria because of the war between Hezbollah and Israel.

Life expectancy increases with age

Daniel Jafferis has pointed out an extraordinary discovery of the social scientists:

• The longer you live, the longer you can expect to live

that was described in the Harvard Gazette. In other words, the social scientists have found a strong circumstantial evidence for the statement that

• if you're Y years old, then you're unlikely to die at the age of X years if X is smaller than Y

For example, if you're 75 years old, it is likely that your life expectancy won't be 60 years. Isn't it amazing? Who could have thought? It's almost as ingenious as loop quantum gravity, especially if you realize how much money both of these things swallow.

New official confirmation of McKitrick & McIntyre

Even though many people like to say that 1998 was the warmest year in the millenium, the underlying statistical treatment by Mann et al. - also known as the hockey stick graph - has been discredited by more recent investigations.

The recent report of the NAS panel could not confirm the millenial assertion of Mann, Bradley, and Hughes, citing high levels of uncertainty. Moreover, the House Energy and Commerce Committee made three researchers, Edward Wegman (a rather well-known statistician), David Scott, and Yasmin Said, to look at the hockey stick graph again. In a report that was just released, the criticism by McKitrick and McIntyre was confirmed. Mann's method is selectively mining for hockey sticks.

Sources:

• U.S. House: Factsheet
• Wegman report: full
• Wall Street Journal (subscription)
• Climate Audit & after the release
• National Center for Policy Analysis

The U.S. House committee has found that the sharing of research material, data, and results were haphazardly and grudgingly done. The players relied on peer-review too much even though it was not independent. The statisticians have studied the social network - the collaboration graph - of the extended hockey team in detail and showed that virtually all of the "independent" peer-reviewers are Michael Mann's direct co-authors, while some "cliques" are completely disconnected.

Moreover, the topic was too much politicized which makes it hard for the researchers to re-evaluate their public positions without losing credibility. I would interpret this insight as a calculation showing that Mann et al. can't really offer anything positive to science in the future. The Mann et al. research did not provide any evidence that the 1990s was the hottest decade in 1000 years and 1998 was the hottest year.

The statisticians also correctly conclude that blogs are not a good place for a scientific debate on this issue - which certainly holds for many other issues, too.

The main villain, Mr. Michael Mann, has replied that Profs. Wegman, Scott, and Said just uncritically "parrot" an economist and an "oil industry consultant" (McIntyre has worked as a consultant in hard-rock mineral mining industry), while he offers several paragraphs of downright lies about the recent report of the NAS panel. It is not a terribly constructive approach to members of the committee like David W. Scott who seems to have contributed to science more than Mann has, even if we count his flawed hockey stick papers.

Mann's frequently publicized picture of the world as a class struggle between the oil industry and heroic activists like him show that he is mentally ill, politically radical obsessed person who not only has nothing to do with a serious, prejudice-free approach to scientific questions, but who is also slightly dangerous for the society.

Peter Svrček: quintessence with small vacuum energy

Peter Svrček proposes to explain the cosmological constant as

• quintessence based on axions.

He is thinking about a compactification of M-theory on G2-holonomy manifolds and/or various type II string theories with a large number of axions. The potential for these axions is generated from D-brane instantons, and if the action of the instanton is around 210-290, Peter argues that you obtain more or less the observed value of the cosmological constant.

Yes, the number is the exponent from Polchinski's new favorite form of the cosmological constant written as a multiple of "M_{Planck}^4".

As far as I understand, Peter still does not explain why the remaining contributions to the vacuum energy cancel, but if they cancel, he could eliminate one of the "new cosmological constant problems" that appeared when a nonzero value was measured.

I was just thinking about a framework to imagine that the SUSY breaking is mathematically analogous to the chiral symmetry breaking: in the latter case, small bare quark masses break the chiral symmetry and imply a vev of quark bilinears that is much larger - at a scale somewhere in between the bare masses and the QCD scale.

In a similar way, small bare masses in the milli-eV range could create vevs around a TeV that split the supermultiplets, but the vacuum energy could still be dictated by the small bare masses.

LHC: Lords of the ring

The Seed magazine is one of the world's epicenters of the soft scientific jelly - science and culture, science is culture, all of us are interested in the same things, there is just a small continuous difference between a guy from the street and Juan Maldacena, blah blah blah as N.A.-H. would say :-) - but it may be fun anyway to link to their movie about the LHC collider:

• Lords of the ring

The movie is in Apple's MOV format. If you don't want to install their QuickTime player just because of this video, it may be better for you to install

• QuickTime alternative

for Windows that will allow your Windows Media Player to play movies in the Apple format.

Basayev: death was not enough

Mark Trodden at Cosmic Variance celebrates that the BBC conjectured that the terrorists and their buddies at Guantanamo Bay will enjoy increased luxury in their lives. As you can imagine, your humble correspondent celebrates very different things, and in some sense the very opposite things than Mark Trodden does.

Ladies and Gentlemen, most of you have probably heard that Shamil Basayev is dead. The Russian president correctly says that death is not enough for such a monster. Well, Basayev is responsible for hundreds of deaths - 300+ people in the school at Beslan, the Moscow theater siege etc. - which are thousands of times more valuable than his life.

There are other reasons to be happy that this Islamic terrorist has joined his buddy al-Zarqawi. Basayev thought that Osama bin Laden had to be a great person because his face always emits light on all photographs. Moreover, Basayev was obsessed with the very same human garbage as some of our liberal friends - namely with the communist terrorist Che Guevara. ;-)

We may be cautious about Russia in many subtle cases and we can also sympathize with many nations whose independence was suppressed by the Russian bear, but in this particular case, all good people should admit that the Chechen Islamic terrorism affecting Russia is completely analogous to the Islamic fundamentalist terrorism directed against America and other Western countries. Basayev's death is not a sufficient punishment but it is still a good news.

I wonder whether the explosion was a result of a good work of the Russian intelligence forces or whether it was a genuine accident. It is likely that we won't ever learn the answer, and if we learn it, it will not necessarily be the correct answer because of the intense propaganda war in the background.

Dualities and equivalences

Most of the misunderstandings of physics and myths have a characteristic left-wing flavor. The following flawed concepts can often be identified as the primary obstacles that prevent many people from comprehending certain important ideas in theoretical physics:

• social arguments used to find the answers to scientific questions
• egalitarianism of theories, ideas, or even numbers

The first error appears whenever someone tries to guess a correct answer to a physical question according to various social features of the proponents of the different answers - which is a typical approach of postmodern social scientists. In the 1930s, some German physicists would discard a physical theory because its discoverer was Jewish. Most of us are no longer doing the same mistake but many of us are doing similar mistakes. Some people think that only famous or highly-paid people can be right. Other people think, on the contrary, that it is only the outsiders who should be correct and those who have been believed to be right so far must have been cheating. A third, "neutral" group of people believes that all people talking about physics should be right equally frequently. Then there are people who believe that only tough physicists may be right, and other people who believe that only polished or sissy liberals can be right. Needless to say, all these and similar ideas are scientifically absurd. Correct scientific ideas can indeed emerge in all environments. They are more likely to occur in some environments but one can never use the environment as a universal criterion because the probabilities that the right ideas occur in all environments are nonzero. All these arguments are unscientific.

The second error is based on egalitarianism of ideas, theories, formulae, or numbers. This error can also be described as the celebration of ignorance. Imagine that a schoolkid is asked what is Ohm's law. The kid answers "U=RI" or "U=R/I" or "U=I/R" or "U=1/IR", and perhaps also "U=R+I". The teacher won't be too satisfied and the kid won't have the opportunity to become terribly proud about her ignorance.

However, there are cases in which there is no teacher with the desired authority around. Our colleague from Santa Barbara argued that because we have not seen an evaporating black hole yet, all real positive numbers are equally good candidates for the entropy/area ratio. One quarter is just one possibility among infinitely many - just like ln(3)/sqrt(2)pi. Well, it is just one possibility among infinitely many from the viewpoint of a person who does not know how the semiclassical calculations are performed. More than 30 years ago, these calculations have shown that the correct constant is certainly one quarter, and independent microscopic calculations in string theory always confirmed this number. There is no doubt that "S=A/4" for macroscopic black holes. You can guess that once the colleague from Santa Barbara writes that she is a wiser, brighter, more tolerant, more cultural, broader, or a better human being because she considers all numbers to be as good as "1/4", my blood starts to boil. I just can't stand this behavior. If someone is ignorant about something and she admits it, it's OK. But if someone starts to paint her ignorance as a virtue or even the essence of humanity, it becomes a small disaster.

Similar egalitarian myths lead many other people to believe that the probabilities that string theory and loop quantum gravity are correct must be comparable. Fifty percent of people should be working on each, and so forth. Some people just can't understand reality. The fact that the probability that string theory is correct exceeds the analogous probability for loop quantum gravity by dozens of orders of magnitude is something "unfair" for them, and they just don't want to accept such a fact because it does not agree with their egalitarian sentiments. It's just like the "unfair" fact that Bill Gates is richer than others.

It is thus refreshing to see anti-egalitarian myths in action. At last, one can see some diversity here. ;-) The myth I will be talking about below is the misunderstanding of the meaning of "dualities" and "equivalences" in physics. The particular discussion that led me to write this text was about the gravity dual of the phenomena at RHIC - i.e. the gravity dual of QCD. Because this particular gravity dual is not exactly uniquely and exactly known, let me talk about a similar theory where the gravity dual is known perfectly: the N=4 gauge theory in 4 spacetime dimensions that is dual to type IIB string theory on the product of a five-dimensional anti de Sitter space and a five-dimensional sphere of the same radius. If the program to search for the gravity dual of QCD succeeds perfectly, the situations will be perfectly analogous. Consequently, we can talk about N=4 gauge theory without a loss of generality.

An anonymous reader suggested - and interpreted a comment by Prof. Mark Srednicki - that the dual gravity calculations in AdS/CFT are just mathematical tricks, but the "real" physics is still physics of gauge theory. He or she proposed an "analogous" example with a pendulum and an electrical circuit. The fact that they follow the same equations does not mean that we can say that an electrical circuit is a pendulum. Fair enough.

But the situation in AdS/CFT or any other duality in string theory is very different. In the case of the pendulum, we can find many other physical features that distinguish it from the electrical circuit. A pendulum should have a certain design, people with common sense would say. A more sophisticated way to distinguish a pendulum from an electrical circuit is based on the fact that the pendulum oscillates because of gravity, and the oscillations thus emit gravity waves made of gravitons whose spin is two, which you can measure in principle, while the circuits emit electromagnetic waves, streams of spin one photons. At any rate, there are other details that distinguish the two cases, and the two systems only share the rough differential equations. We have tools to say: this is a pendulum, not an electrical circuit.

But in the AdS/CFT correspondence, there are no other details that could tell you whether your world follows physics of gravity or physics of the conformal theory. Any phenomenon on one side has an equivalent description on the other side. It makes no sense to ask which of the two descriptions is correct if they are fully mathematically equivalent. It is equally meaningless as asking whether the German or French translation of the European constitution is correct. (In the latter case, both of them are wrong, of course.) It is equally meaningless as asking whether the Schrodinger picture or the Heisenberg picture is correct. These frameworks use slightly different concepts or intermediate equations, but they lead to exactly identical predictions of those physical observables that can actually be measured.

If such an equivalence is obvious, we would not spend hours with it; we would say that the "two" things are simply one thing. Equivalences in modern theoretical physics are only interesting because they're not so obvious. We like to use the word "duality" because the two descriptions of the same physics originally look like two different theories. Obvious examples include strong-weak S-dualities, large-small T-dualities of compactifications, large-weak-strong-small U-dualities mixing many parameters, and especially the gauge-gravity and AdS/CFT holographic dualities relating a gravitational theory with a non-gravitational theory defined on the boundary of the gravitational spacetime.

In each case, it is simply meaningless to ask which of the two descriptions is correct and which of them is just a trick. If they're exactly equivalent - giving exactly the same predictions for physically measurable quantities such as cross sections - they are equally correct. Because they're equivalent, it means that if one of them is a relevant set of laws for XY phenomena, the second of them is relevant, too. If one of them is irrelevant, the other is also irrelevant. If one of them is valuable, the other must also be valuable. And so on, and so on.

One of the descriptions might be more useful in one context or another, but usefulness and the truth are different things. For a theoretical physicist, they are very different things.

In the particular case of the gravity dual of QCD, it is indeed important to note that the gravity dual is not just a "trick" but the "real" theory of the phenomena in different variables. If you are optimistic and imagine that our colleagues will find an exact gravity dual of the Standard Model, such a geometry will literally be a part of the geometry that is relevant for the real world in string theory. Because the Standard Model is not valid at arbitrarily high energies, the geometry dual to the Standard Model will have to be cut and modified to obtain the geometry describing everything - it will have to be glued to a smooth Calabi-Yau manifold, to mention the most typical example, that will be responsible for the physics at the Planck scale.

At any rate, if the program is fully quantitatively successful, one will obtain a background that carefully follows the rules of string theory. By string theory, I mean the same theory that other string theorists study, with the same strings, branes, black holes, low-energy fields, their interactions, transitions, moduli spaces, and everything else. The same string theory that is most likely the correct description of everything in the real world including the ordinary gravity in four nearly flat spacetime dimensions.

In the case of the gauge-gravity duality or any other exact duality in string theory, claiming that one side is true and the other is either wrong or just a "trick" is simply a misunderstanding of the meaning of the concept of dualities. Dual theories are exactly equivalent, no one has any right to discriminate against one of the dual descriptions, and when we talk about string theory, we always mean the same string theory that always contains quantum gravity, and always contains other forces and objects. The gravitational duals of gauge theories are backgrounds of string theory. String theory in this context or any other context is no trick but reality, and once we accept that the rules of string theory are relevant for some questions in physics - such as the dual description of gauge theories - the rest of string theory logically follows from the same rules. Within the established theoretical insights of string theory, there is no way how to build walls of political correctness within string theory that would separate things that can be done and that are valuable from those that aren't. Only people who misunderstand the internal structure of string theory - for example a certain controversial blogger at Manhattan - propose to build such walls.

And that's the memo.

RHIC: string-bashing beats child pornography

Imagine that it is 2006, you are a very big guy and a boring blogger who has nothing interesting or insightful to say. The only virtue of your blog is that it is one of the thousands of uninformative worthless and colorness negativistic far left-wing activist anti-Bush anti-capitalist anti-American anti-religious pseudoscience blogs - and you want to increase the traffic on your particular blog by 500 visits a day. Moreover, you have virtually no moral constraints and all principles you might have are uncertain principles. What do you do?

Many readers might think that you transform your blog into a source of child pornography. But one blogger has found a better solution of the situation described above:

• As for the comment about string theorists, that was not entirely serious - it was some linear combination of an oblique reference to the antics of a certain individual theorist, and a cynical attempt to drive traffic (because I almost always get a bump in traffic when I talk tabout string theory - think I could pick up an extra 500 visits/day by posting one piece daily with the title "String Theory Is a Bunch of Crap").

This is what he did and it apparently worked. He wrote a complete nonsense about the relation between RHIC and string theory, proving that he not only misunderstands how this relation works but he is not even aware of it. We discussed related topics seriously in these articles:

• Horatiu Nastase and RHIC
• Bounds on viscosity divided by entropy density

Musings have discussed similar exciting links in these texts:

• AdS / quark gluon plasma I, II

Chad's recipe is easy, and it is being used by a dozen of other bloggers - one blog at Manhattan is actually entirely dedicated to this activity. You write a complete bullshit about a topic that you have no chance to understand - such as the relation of RHIC and string theory - and you squeeze a huge amount of irrational hatred against theoretical physics and string theory into such a text. If you want additional 200 hits, you include some Goebbelsian lies about the owner of The Reference Frame, too.

The overall result is that you increase the traffic to your blog by hundreds or thousands of visitors a day. Moreover, most of these visitors will be idiots who won't even be able to guess that what you write is a complete nonsense and that you have no idea what you're talking about - which is actually a composition of readers that some bloggers deliberately look for. Of course, another step in their algorithm is to paint the hundreds of idiots and crackpots as smart people.

Your humble correspondent would be happier if there were a tool to reduce the traffic by 500 visitors a day from this category.

If you're actually interested in the physics, a recent (May 2006) instantly well-known article about the AdS description of the quark-gluon plasma was written by Steve Gubser. You may also be interested in the December 2005 paper by Janik and Peschanski and a paper by Shuryak, Sin, and Zahed from November 2005. The dual description of strongly interacting physics provided by string theory is a rather exciting set of insights. On the other hand, it is extremely far from being the only physically exciting insight in string theory.

Via Musings.

Jacques Distler's patience

The discussion at Musings about

• Coupling matter to loop quantum gravity

has been very long, and whoever is interested in this hypothetical alternative to string theory may want to read it.

Jacques Distler has originally asked a simple, well-defined question, but he can't get any answers although he has probably deduced the right answers from the non-answers anyway if he did not know them already before the discussion. ;-)

He is asking which gauge theories and which matter spectrum can be coupled to loop quantum gravity, and how does the anomaly cancellation constraint appear in the formalism?

That's a very clear question. If you asked the same question in any completion of a gauge theory that works, you could get a clear answer. For example, if you ask this question about type I string theory, you can present the cancellation of worldsheet anomalies that makes the full scattering amplitudes finite and cutoff-independent, which also guarantees the cancellation of the spacetime gauge anomalies, although the required mathematics looks highly non-trivial and different. But formulae can show that the cancellation of the worldsheet anomalies does imply the cancellation of spacetime anomalies.

Incidentally, Jacques has described very clearly how Lee Smolin misunderstands the word "finite" in physics. In properly done physics, finiteness of a theory means that the results are cutoff-independent. Lee Smolin uses the adjective "finite" for a theory that has been given a cutoff, without requiring any independence on the cutoff and physics near this cutoff scale. Putting a cutoff is always possible and easy, but it is a very different thing from solving the actual UV problems of a physical theory.

These problems are only solved if the framework generates results independent of the possible choices of the cutoff and the terms at the cutoff scale. String theory achieves this independence completely and removes all parameters; effective field theory achieves this goal approximately because relevant and renormalizable interactions at low energies only depend on a finite number of parameters. Nonrenormalizable theories as well as loop quantum gravity fail to satisfy the finiteness constraint.

In other contexts of string theory, you could show that only anomaly-free effective field theories are generated. In various subsets, you could say that you only generate non-chiral theories where the anomalies are absent and there is no interesting question to ask and calculate. In the case of dimer models, you could translate the anomaly cancellation conditions to a geometric language. At any rate, if you understood your formalism at least infinitesimally, you could have provided Jacques with a clear and complete answer within 10 minutes.

Jacques is asking these questions because he knows very well that the theories of chiral fermions are very problematic in the approach via lattice regularizations. If LQG is compatible with very basic properties of the world and particle physics and gauge theories in its low-energy limit, it must be able to reproduce the same conditions of the gauge anomaly cancellation.

By now, all of us more or less know that loop quantum gravity has no features that would make it more physically acceptable than other latticizations. One could simply answer Jacques' question with this answer:

• At this moment, we don't seem to get any constraints on the UV physics, we don't know whether we get a correct low-energy limit, and we don't know how the anomaly constraints arise.

We would offer such an answer in new approaches to string theory whenever such an answer would be correct. Instead, Lee Smolin is offering answers that look like commercials addressed to a very undemanding audience. Everything great can be done, and if it has not been done, it will surely be done quickly, and so forth. Neither of these sentences has anything to do with the hard core of Jacques' question. It's just a meaningless jelly.

Sometimes, the answers of the loop quantum gravity advocates use technical language, and if you try to interpret their sentences as assertions about science, you will find out that they are plain wrong. There is a long subdebate about the simple connectedness of the configuration space of loop quantum gravity, and so forth.

Every time Jacques or someone else offers a no-go theorem with a proof showing that a certain mechanism simply can't work or is plagued by an error that can be sharply described, Lee Smolin argues that the methods can't be used because LQG is something different, it is more and transcends the arguments of mortal beings like Jacques. Using Jacques' words, Lee Smolin indeed seems to believe that he has co-invented a new kind of science. ;-)

This kind of jelly-fish nonsensical chatter makes no sense to me. If a theory can't reproduce even the very general features of low-energy physics that have been experimentally verified, such a theory is in a big trouble. There is certainly no reason to celebrate because the theory, if the word theory is appropriate for a structure that has infinitely many continuous unknowns, has no implications for physics.

Another loop quantum gravity advocate called "fh" honestly says that

• if you think that physics is about a description of interactions on Fock spaces, then LQG is not even wrong, utter failure, silent, and unable to say anything.

Jacques is being nice so he says that he does not think that this is what physics is all about. Your humble correspondent however thinks that all of natural science is about objects and their properties, and according to the cutting edge physics, objects are excitations of quantum fields and they have interactions that can be described by terms in an action. All of particle physics is about the spectrum of possible particles and quantification of terms that allow them to interact. Even string theory can be interpreted in this framework if you extend it appropriately (e.g. allow string fields in string field theory).

There are more diverse insights in physics than just talking about the spectrum of an operator and the values of the couplings, but even these diverse insights are indirectly insights about the spectrum and the couplings.

If a theory cannot say anything about the spectrum of objects and their interactions, then it cannot say anything about physics. A theory can claim that the fundamental objects are really different than quantum fields in spacetime - and various formalisms in string theory indeed tend to say that locality in spacetime is something emergent and not fundamental - but you must still be able to use your more fundamental building blocks to derive the known properties of physics as encoded in classical GR and the Standard Model, or at least qualitatively similar theories. If you can't do it, you just have nothing to say about physics.

Another line of Lee Smolin's argument is that no one likes canonical loop quantum gravity too much anyway because people are switching to spin foams. First of all, all major canonical LQG practitioners such as Thiemann or Ashtekar are continuing with the canonical LQG approach. Second of all, switching to spin foams makes no difference because no explanation of anomaly cancellation (or other mechanisms from real physics) exists in the spin foam framework either.

Lee also asks:

• Do you really believe that a lot of smart people have worked for 20 years on something and just fooled themselves?

No, I don't think so because of at least two reasons. First of all, it has been more than 20 years, and second of all, I doubt that the adjective before the word "people" is overly accurate. ;-)

The way how the loop quantum gravity jelly-fish debaters try to avoid any calculation, any answer, learning of any new understanding of physics that actually makes sense, or any inconvenient conclusion in this debate about anomalies in LQG indicates that they could fool themselves or comparably "smart" people not only for 20 years but for 1000 years if necessary. They just have not understood what hard science means, in which case 20 or 1000 years make no difference. The Earth has seen millions of years in which no significant progress in science was made by smart people. Sorry, I mean people. Sorry, I really mean apes. ;-)

The questions that they were trying to answer incorrectly for 20+ years can be answered correctly by a good high-energy physics student who just defended his or her PhD in 1 hour. That does not mean that the grad student is 200,000 times smarter than the loop quantum gravity community because the relation between the intelligence and the rate of making progress is nonlinear. ;-)

Hep-th papers on Monday

There are seven papers on hep-th on Monday.

Jarah Evslin and Hisham Sati focus on some subtle differences between K-theory and homology in defining charges of D-branes. Recall that homology used to be viewed as the right classification of the possible lattices of charges of D-branes, in agreement with the simple picture in which a D-brane wraps a submanifold. However, work based on tachyonic considerations of Ashoke Sen has led Edward Witten to argue that K-theory, a structure analogous to homology but based on gauge bundles, is a better more accurate description of the charges because it treats some torsion classes more carefully. The present authors study homology cycles of nice smooth manifolds that cannot be represented by a nonsingular submanifold. I suppose they mean a connected submanifold. For cycles that can be represented by submanifolds, the Freed-Witten anomaly must cancel for the cycle to be usable as a living room for a D-brane. K-theory, a huge hobby of Jarah Evslin, contains most cycles that homology does, but as the authors argue, some of them must be non-representable by submanifolds. Examples are provided.

Tamiaki Yoneya reviews the Penrose (BMN) limit of the AdS/CFT correspondence. It's really one talk so don't expect that he gets to things as complex as integrability or magnons.

Kazunobu Maruyoshi studies gauged N=2 supergravities with various U(1) and U(N) vector multiplets that he breaks spontaneously to N=1 supergravity. Although the resulting theory probably can't have chiral couplings and can't be semi-realistic (which makes it different from the usual mechanisms of supersymmetry breaking in phenomenology), and although the implementation into the big picture of string theory is not given, I must say that it is a very impressive master thesis.

Larus Thorlacius looks at the black hole information loss. Most of the time, we would study the causal subtleties of the propagation of information with the example of a Schwarzschild black hole that has a spacelike singularity. However, the Penrose diagram of a black hole that is charged just a little bit looks different. The Reissner-Nordström diagram can be maximally extended to an infinitely long vertical strip with infinitely many timelike singularities. This picture should be, in some sense, more generic than the exact Schwarzschild picture. Thorlacius offers an argument that assumes black hole complementarity - the conjecture that the degrees of freedom inside a black hole are not independent from those outside - and concludes that the evolution can't respect unitarity or that the information must be lost because of the Cauchy horizons. My interpretation, of a person who thinks that the preservation of information at infinity is an established result, is that Thorlacius did not take the non-locality properly into account, and if he did, then it means that the interior of charged black holes must look very differently than the classical causal diagram indicates, even though the difference could be less dramatic than what Samir Mathur proposes.

Hristu Culetu likes to view the horizons in general relativity as one-way membranes. While everyone agrees that the entropy "S=A/4G" should be assigned to all macroscopic horizons including the Rindler horizons - recall that Rindless space is a flat Minkowski space interpreted by a uniformly accelerating observer - the author notes a discrepancy about the energy that we normally assign to the Rindler horizon. He modifies the formalism in such a way that the horizons always carry the energy of "E=r/2", including the Rinder horizons that were previously said to carry no entropy. I am not sure whether these additive shifts have a well-defined meaning anyway. Overall additive background-dependent shifts to the energy only matter if you can compare two different backgrounds by a physical experiment. The exact result depends on the details how you do the Wick rotation and how you treat the boundary terms in the action or energy.

Baumann, Dymarsky, Klebanov, Maldacena, McAllister, and Murugan look at type IIB (or F-theory) flux compactifications that involve warped geometry which makes them perfectly suited for a stringy realization of the Randall-Sundrum ideas (besides being the canonical stringy playground for the anthropic speculations). Take this warped geometry with the throats and throw a D3-brane into it. Study its motion. You will be able to describe the motion by a potential. Recall that there is more structure in these backgrounds. The sizes of four-cycles - Kähler moduli - are stabilized by certain objects wrapping the four-cycles. The authors confirm a qualitative form proposed by Ori Ganor and compute the superpotential relevant for the D3-brane to be a function of the warped four-cycle volume. Because their SUGRA / closed string loop calculations remain nicely holomorphic, they can also tell you how the holomorphic gauge couplings can be expressed as functions of the geometric parameters of the compactification.

David Kastor and Jennie Traschen study how the thermodynamics of black holes in Kaluza-Klein theories changes under infinitesimal changes of the moduli parametrizing the compactification. From thermodynamics, you know the "dE" contains terms of the form "p dV", and they also tell you something about the similar terms in which "dV" is replaced by various variations of the compactification moduli. Well, if you know the energy "E=Mc^2" as a function of the moduli, you really don't need more than basic knowledge thermodynamics. The new quantities analogous to "p" and "dV" will carry two extra indices for toroidal compactification. And I am not quite sure whether the experts learn something new from the nicely-written text.

Culture wars: hard vs. soft sciences

For a few decades, we could have observed symptoms of the culture wars between the scientifically minded scholars and people in general who think that their task is to search for the truth using the hard, scientific methods on one side - and humanity oriented academics and social scientists who think that the task for the Academia is to search for the "truth" by the easy, social methods, by consensus, and the main criterion of success and truth is whether they look nice according to other soft people.

Recently, the soft side has been vigorously attacking the hard side and the hard side does not seem to be defending itself anymore. The extremely soft segments forced Lawrence Summers, an eminent economist and an extraordinary university leader, to resign. There are many episodes behind the Summers controversy. However, the main lasting consequence of this story for the big picture is clear: the resignation was a significant victory of the soft side in the culture wars.

The adjectives "hard" and "soft" are not separated sharply. There are many levels and flavors of "hardness" and "softness". However, there are many fields that can be classified almost unequivocally as "very soft" or "extremely soft" fields. They include sociology, women's studies, African American studies, literary criticism (plus journalism), and several others. On the other hand, some social sciences - especially economy and partly political science - are on the harder end of the social sciences. Natural sciences tend to be "hard". Physics, engineering, and much of chemistry are among the "clearly hard" fields. On the other end, Earth and planetary sciences and parts of life sciences are softer. Whenever I talk about hard or soft fields below, I mean the idealized hard and idealized soft fields or the hard and soft essence of all fields. My conclusions are certainly not meant as universal statements about every individual member of a large group of departments but as a description of certain tendencies that are dominating in one group of fields or another. Also, my goal is not to trash social sciences and humanities in general whose existence makes the society richer in so many respects. There are many people in these fields I deeply respect. Instead, I only criticize the features of soft sciences that are important for the culture wars.

What are the differences in the two groups' understanding of the truth?

Hard sciences attempt to understand (and use, in the case of applied sciences) the phenomena in the real world. To do so, they must always consider different hypotheses that are conceivable a priori and choose among them by a careful evaluation of the observational data, artificially prepared experiments, and a sufficiently refined theoretical reasoning. In these considerations, it never matters who is proposing a particular scientific work. It doesn't matter what is her or his race, nationality, profession, or sex. It doesn't matter what is his or her political power and whether various groups of people like her or him or not - and whether they like her face, clothes, or vocabulary.

Soft sciences make students memorize a certain amount of material and insights that are not related with each other, and if they are, the relations are comprehensible to most ordinary people. This lack of unifying structure is often compensated by artificially invented principles which usually means a political ideology. The right ideology is chosen according to the ability of their proponents to convince others, according to their face, vocabulary, friends, political allies, and according to the people whom they eat with and sleep with. What matters is whether you belong to a group that is being liked by others or viewed as a politically correct group. Depending on the mood in the society, being a Jew or a woman can be a tremendous advantage or a tremendous disadvantage. Social sciences sensitively depend on the political twists in the society and they magnify their effects which is why they are also controlled by groupthink most of the time.

It should not be surprising that a major part of the soft sciences criticized in this text are sciences that are currently blended with far left-wing political activism.

The arguments in the idealized soft sciences have no material substance, especially not substance that requires scholars to think intensely for extended periods of time. Instead, these arguments are primarily composed of philosophical preconceptions that make their proponents "feel good" and that make them look nice in the eyes of a sufficiently powerful segment of the society. Much like in the case of stars of porn industry, the good soft scientists are chosen by those who are less experienced experts because there exists no independent method that experts would have to learn before they become able to evaluate the ideas. If such a method existed, the field could be studied by hard scientists, too. In other words, the most successful representatives of soft sciences are the most successful spokespersons of the most widely held ideas in the society. In most cases, the most widely held ideas are myths.

As suggested above, the education in the idealized hard sciences is hard and the education in the idealized soft sciences is easy in comparison. The grading and other procedures are relatively objective in hard sciences and relatively subjective in the soft sciences. While the various levels of education in very hard sciences make these fields learnable for subsets of the population whose size decreases dramatically at each new level, the whole education in soft sciences is essentially open to a significant fraction of the population. In some sense, the required concepts do not go qualitatively beyond the elementary school. The emphasis is on relatively simple manipulation with language, letters, words, and notions whose meaning is almost always defined verbally, in terms of other words.

Equivalently, hard sciences focus on the content while the focus of soft sciences is on the form: they are more superficial. A different choice of a word or terminology is something that would never affect conclusions that hard scientists are ultimately interested in. On the other hand, subtle changes of words are very profound for soft scientists. Hard scientists are interested in a bird's physiology; soft scientists are interested how the bird is called in different languages.

Typical hard scientists' IQ is by 15-30 points higher than the typical soft scientists' IQ. Soft warriors in the culture wars ideally don't like any hard data - and this hard data is no exception - and they prefer to invent constructs that justify their denial of the hard data.

Hard scientists realize that the world follows certain laws of Nature, and the society is no exception except that these systems are so complex that the fundamental laws sometimes cease to be useful for the analysis or management of these complex systems. Soft scientists don't realize (or don't "accept") that the world follows natural laws. The idealized soft scientists think that the society or a word (logo) was primary and natural laws are social constructs, much like everything else. In other words, most idealized soft scientists deny any objective reality. They think that all the world follows the rules of their "science" - everything is determined by politics - and they are trying to impose this highly misleading philosophy upon the whole Academia and beyond.

Nowadays, most journalists, including the self-described science journalists, seem to fit squarely in the soft realm. They were trained to be able to work with the words and to respect the rules of grammar. They were trained to combine the words in ways that superficially look fair. They never want to look inside ideas or debates. Consequently, they can only choose the right voices according to their feelings or their colleagues' feelings. They give room to people whom they eat with, whom they sleep with, whose smile they like, and whom they feel compassion for. The more intellectually complex a given topic is, the lower value the average result of the soft journalists' work inevitably has. They never want to comprehend some principles revealed by science to the point that they could check the principles themselves. The most complex principles that the soft journalists wish to learn are childish conspiratory theories - such as the idea that the evil oil industry is going to burn the planet by 2016. They don't want to be better, and as indicated above, most of them are not able to do better. Once they learn some oversimplified childish principles, it is very difficult for them to unlearn them.

If soft scientists and hard scientists look for an answer or if they debate, the hard scientists want to look at the question under consideration carefully enough so that the critical issue can be localized and the answer can be determined by objective methods. The idealized soft sciences prefer to follow their dogmas, pre-determined opinions, and intuition from the past, or they tend to think about the political consequences of a particular answer for the future. They rarely look at the results of the present experiments and they can rarely admit that the correct answer to a question is one that they don't like. Most of the important things they have learned were taught at the basic school, and the rest of their intellectual life is just about collecting evidence and (mis)interpretations of the new facts that allow them to believe that their opinions crystallized after the elementary school were correct.

Needless to say, the approach of hard sciences is the opposite one. Their goal is to make progress, which means to make the future knowledge higher than the past knowledge, and the inevitable condition for such a development is to get something positive from the present - from present calculations, considerations, experiments, or observations.

Hard sciences and soft sciences evaluate the importance of principles and ideas very differently, especially in the context of teaching. In hard sciences, it is obvious that students must learn how to think scientifically, and they must learn the basic theories of their fields whose ramified and extended versions lie at the core of more advanced or more specialized subfields. In this sense, hard sciences respect a certain hierarchical structure of knowledge. It's because there are many logical relations between different insights. The soft sciences lack these sharp relationships in most cases which spoils the hierarchical nature of their tree of knowledge. Consequently, the teachers in extremely soft sciences often want to avoid teaching of basic skeletons of knowledge, and they prefer randomly chosen personal and ideological (mis)interpretations of very special and largely inconsequential questions in their fields.

The (post)modern very soft scientists prefer to replace encyclopedic knowledge where individual entries are supported by evidence and by each other and independently verified by a continuous random flow of soft plasma where no idea should be checked separately from others. Every time a hard scientist wants to locate the hard core of a question and look at it carefully, the soft scientist tries to hide the core in an artificially produced jelly that can't really be grasped by hands or by brains. Whenever a hard scientist thinks that we have just found the hard core and we are about to learn something, the soft scientists switch to a different topic or general cliches.

This difference is one of the examples that the very soft reasoning also exists in the hard scientific fields. In climate science, we face a lot of scientifically illiterate journalists who are excited if they are able to understand an idea such as the theory of the evil oil industry that is going to burn the Earth by 2016. But even many people paid as scientists are very soft. When people in many groups agree that the climate reconstructions are perhaps the single most well-defined tool to see whether the human influence on the climate exceeds the natural factors and whether it is unprecedented, they just don't want to look at the corresponding scientific work carefully enough. They don't care whether it's correct or wrong - and they openly tell you so - because what they're really building upon is not hard science. They are building on pillars of soft science such as the social consensus, the popular support for widely held myths.

Very similar comments apply to the critics of theoretical physics. Whenever any particular question is being discussed - such as the question whether the coefficient 1/4 in the black hole entropy could be something else such as "ln(3)", they just don't want to look at the particular papers in detail. Many of them despise all serious papers. The epithet "not even wrong" is nothing else than a clear expression of hatred against hard scientific thinking in general. People who follow the "not even wrong" reasoning don't ever want to read or write any serious paper. They have already decided that about the truth without looking at a single technical question carefully. They have decided by the methods of very soft sciences. Various Peters Woits are extremely soft intellectual jellies - or jelly fish, if you wish - that you never want to touch because nothing useful can ever come out of it. The contrast between people like Peter Woit and hard sciences could not be sharper. In hard science, it is the whole idea to look for the most natural theories that are compatible with the real data - theories that are "not yet wrong". Hard sciences can never find theories (except for the ultimate and complete TOE) that are "forever correct". The only thing that hard sciences can find is a theory that is still working fine, a theory that is "not yet wrong". The fact that the jelly-fish critics of science try to humiliate this important principle by their epithets such as "not even wrong" proves that they have not understood what science is all about.

The softer and more intellectually rotten the popular discourse about a class of questions becomes, the less quantitative concepts you can see in it, the more complicated speech code and set of tabboos you face, the more political arguments you encounter, the more frequently you hear that there exist arguments that no one actually knows (classical emperor's new clothes), and the more often you can hear ad hominem arguments that someone is "not nice" - because being nice is nothing else than being another supersoft jelly-fish with entirely unscientific and "socially acceptable" opinions about everything that the other jellies want to produce from the whole humankind.

Be afraid. Be very afraid. Unless you invent an efficient way to decompose the jelly into usable carbon and hydrogen atoms that could be used to construct something more valuable. It's not an easy task because the jelly of lousy science journalists, critics, and soft academics is set to increase exponentially.

CO2 vs temperature: ice core correlation & lag

Abstract

The temperatures and carbon dioxide concentrations have been correlated - see e.g. Petit et al., Nature 1999 - but we know for sure that the temperature was the cause and the concentration was its consequence, not the other way around. This fact has also been explained in The Great Global Warming Swindle. It follows that the C0₂ greenhouse effect has not been important in the history and we shouldn't expect that it will become important in the future.

Special comment for Australian readers on Sep 28, 2007: just yesterday, there was a new paper in Science - Lowell et al., Science 2007 - that showed that CO₂ lagged by about 1,000 years when the last ice age started to end 18,000 years ago

The direction of the causal relationship can be shown in many ways: for example, it is not just CO₂ but other gases such as methane that follow temperature. The hypothesis of CO₂ as the primary reason wouldn't explain why these other gases are correlated, too. Also, we understand how oceans react to temperature changes by releasing gases. Finally, the gas concentrations lag behind the temperature by 800 years, see e.g. this 2003 paper in Science by Caillon et al.

• See also: climate sensitivity & nonlinear relationship between CO₂ and temperature
• MS Word introduction to the climate debate

Main text

The movie of the former future U.S. president - "An Inconvenient Truth" - has impressed many viewers: it is an optimized promotion of the alarmist understanding of the global climate. Moreover, it shows a more attractive Al Gore than the old Al Gore whom we know from the 2000 campaign.

A few years ago, Gore visited Harvard and with Jochen Brocks, my fellow Fellow, we went to see him. Jochen is a leftist, of course, but he claimed that Gore looked repulsive, unhuman, and evil. I am a rightist but paradoxically, I never had terribly serious complaints about Gore's looks.

Don't get me wrong: I certainly think that George Bush is more human and looks like a more trustworthy and more human being than Al Gore, and I wish him the best on his 60th birthday! Nevertheless, their design is not the primary thing that determines my political and scientific opinions.



That's why I am going to discuss more important issues, namely the scientific ones. The most powerful argument in Al Gore's movie were the graphs showing the correlation between the carbon dioxide concentrations and the temperature extracted from ice data in the last 650,000 years.



Figure 1: Correlations between the temperature and the concentrations extracted from the ice cores (click to zoom in). Combined graph by Thomas Stocker of University of Bern, Switzerland

(Incidentally, if you care, the concentration of CO2 and CH4 is determined by a direct chemical analysis of the bubbles. The temperature is reconstructed from the concentration of frozen heavy water - water with the one normal hydrogen atom H replaced by the heavy hydrogen D, known as the deuterium - in the same bubbles. Why? Because the warmer weather there was, the easier it was for heavy water vapor molecules to get to a sufficient altitude - think about the Maxwell-Boltzmann distribution - and to join clouds whose precipitation was adding ice to the ice sheet during the same year.)

No doubt, the correlation between the temperature and CO₂ is nearly perfect. No doubt, the climate on the Earth in the 650,000 years before the industrial revolution can be described very accurately by a single function of time. But if two things, A and B, are correlated, does it imply a particular causal relationship?

In classical physics, the answer is essentially Yes. The perfect correlation must either mean that A is caused by B, or B is caused by A, or both A and B are caused by something else, namely D. It is completely clear what is Al Gore's answer: the temperature was determined by the concentrations of carbon dioxide. That's why all of us are going to die in a hell by The Independence Day 2016 unless all of us accept Al Gore as the ultimate savior, neglecting that he is not a Christ but rather an anti-Christ as Rae Ann has noticed. ;-)



Figure 2: Climate scientists extract the ice cores.

According to Gore, the concentration of carbon dioxide from the ice core records (see the picture above) was evolving according to its free will and does not require any explanation. The concentration could have been caused by oil companies owned by various mammoths. At any rate, Al Gore does not have to answer why the carbon dioxide concentration was changing in the first place. He does not have to answer because he is the savior.

Now imagine that you have the freedom to think about these things rationally, as opposed to metareligious quasithinking under the influence of crazy brainwashing. First, let us try with the following exercise.

What is the cause and what is its effect

Imagine that you find out that whenever you smell methane in the living room, you can also find a certain person in the same room. The correlation is nearly perfect. What is the conclusion? Someone could propose that the methane in the room is the cause whose presence creates the person. I would propose an "alternative" explanation: it is the person who creates the methane whenever he is in the room. Choose any explanation you want.

I picked methane because it will play a role in the main example, too.

You should notice that the graph above shows a perfect correlation not only between the temperature (A) and the carbon dioxide concentration (B), but also between the temperature (A) and the methane concentration (C). What is the cause and what is the consequence if three quantities are correlated so nicely?

Note that the answer can't be unique a priori. At most one of the three quantities - A,B,C - can be the primary cause. Which one? Clearly, if you choose one of the gases, your explanation will be asymmetric and it won't explain all the correlations in a satisfactory way. If you say that the carbon dioxide concentration determines the temperature, you must still explain why the methane concentration (and other concentrations such as N2O, for that matter) follows the same time dependence. You will clearly need a different explanation. If the CO₂ greenhouse effect is primary, you can't explain why the concentrations of CO₂ and CH4 coincide. Unless you find another inevitable explanation of this subtlety, your theory will be very weak.

Actually, we have more than logical arguments of this kind. We know very well why the causal relation is the opposite one. Imagine that you have a small bottle with 385 milliliters of Coke. It originally contained 4 volumes of carbon dioxide: if you extract carbon dioxide from one bottle of Coke to empty bottles at normal conditions, you will fill four bottles. I had to learn these things when we discussed various thermodynamical issues with Brian Greene when he was writing his second excellent book. Now, imagine that the CO₂ has leaked a bit and there is only 1 volume of CO₂ left in the bottle.

Take this bottle to your car whose internal volume is 1 cube meter i.e. 1 million milliliters. The carbon dioxide from the Coke makes 385 ppm (parts per million) of the volume of your car - just like the ratio in the atmosphere.

Suddenly, you notice a strange correlation between the concentration and character of the bubbles in the bottle on one side, and the temperature in your car on the other side. You will have two possible interpretations. Either the leaking CO₂ in the Coke determines the temperature in your car because the Coke with more CO₂ is a bit darker for the Sun that is shining to your windows (or for the infrared rays reflected from the chairs), or the temperature in your car determines how the bubbles behave in the bottle. Which explanation do you choose? ;-)

I think that any sane person obviously chooses the temperature as the cause and the concentrations as a consequence. Everyone who has ever tried to open a bottle of lemonade during a hot day must know why. Hot liquids are not able to absorb gases so well. Warmer oceans are not able to absorb atmospheric gases either. Clearly, if the temperature goes up, less carbon dioxide and methane can be bound to the ocean waters, which is why their concentration in the atmosphere goes up: this process is known as outgassing.

See: Ocean carbon sink, outgassing, and Henry's law

This explanation obviously works both for CO₂ as well as CH4 and other gases that could appear such as N2O.

There are many other mechanisms that contribute to the correlation between the temperature and the concentrations. For example, the frequency of fires may increase when temperatures are warmer, and fires create more CO₂. Also, the growth of plants and animals (consumers and producers of CO₂) depends on temperatures - but the most important contributions to the correlation work in such a way that the temperature is primary and the concentrations are secondary. If you think for a while, you will realize that the example with the car is actually pretty much realistic and the ability of water to bind gases is much stronger an effect than the greenhouse effect.

Even if you did not believe that conclusion and preferred the Al Gore's explanation that methane and CO₂ create the person or the warming, you will have problems to predict the future. While the correlation between A,B,C was nearly perfect in the past, we have violated this perfect harmony because we produce CO₂ and CH4 at different rates. We can deliberately do so. You won't get any natural prediction for the temperature because the correlation data itself can't tell you how much the two gases contribute.



Figure 3: A map of the Vostok lake. The deeper you go, the further you get to the history because the ice was being added at the top. Different years look like different layers of ice, in analogy with tree rings.

You should better look at physics, and physics tells you quite clearly that the ability of water to bind gases is more important an effect for the correlation than the greenhouse effect, and this fact will influence the measurements from The Subglacial Lake Vostok System, a Russian center in Antarctica (see drawing above). The temperature is the primary cause of secondary quantities such as various concentrations - and I would expect advocates of a "global warming" theory to agree with me that the temperature should be the fundamental quantity. This description explains all the correlations and not just some of them.

Much like all other potential explanations, it still says nothing about the origin of the "primary" quantity, in this case temperature. If temperature is indeed the primary and fundamental quantity, why was it changing the way it did?

There are many contributions to the temperature variations we partially know - such as various periodic astronomical cycles or solar variation - and there are many others that we don't know well or we don't know at all - such as nonlinear chaotic effects in the formation of different kinds of clouds. But I think that even though we don't know some things for sure and in their entirety, we can still be pretty much sure that certain hypotheses are almost certainly incorrect. The hypothesis that the CO₂ concentration was primary and it determined the CH4 concentrations and the temperature is one of such extremely unlikely hypotheses.

And that's the memo. But let us add a cute and important point.

What does the 800-year lag mean

There exists a simpler way to show that the temperature was the cause and the carbon dioxide concentration was a consequence, not the other way around. If you look carefully at the graphs, you will see that the carbon dioxide concentrations lag behind the temperature by 800 years. There have been many papers that found and reported the lag. One of the newest and most accurate ones is this 2003 paper in Science by Caillon et al. (full text, click).



On the graph above (click to zoom in), the past is on the right side, time goes to the left. You can see that the Antarctic temperature starts to change first, and CO₂ responds with a 800-year lag. Methane is still correlated with both. The graph is not new. Today, we have many more accurate graphs of this kind, many of which are from more distant past. We also have a more detailed analysis by Stott et al. (Science 2007) of the end of the last ice age 19,000 years ago where CO₂ lagged by about 1,000 years, too.

The explanation is obvious: oceans are large and it simply takes centuries for them to warm up or cool down before they release or absorb gases.

The work proving the lag was recently explained in Scientific American as well as RealClimate where they also essentially claim that you can easily produce a time machine as long as you want to travel only 800 years - or anything less than 5,000 years - to your past. ;-)

See also: CO₂ lag and how alarmists think

I leave it up to you whether you learn just the hard data or also their bizarre interpretation, and whether you will think that the RealClimate people are sane according to this interpretation. I personally don't think so. They would be right if they said that 90% of the time, the temperature and gas concentrations move together, and if you could hide the remaining 10% of the data, you couldn't learn the direction of the causal relationship.

But scientists who don't want to close their eyes can look at these critical 10% of the data, too. The result of such an analysis is that the impact of temperatures on gas concentrations is much stronger than the opposite influences, including the greenhouse effect. This fact can be extracted from the time periods where the trend is changing but because the physical laws themselves don't change, it is very clear that in the remaining periods, it is still true that the influence of temperature on the gases is stronger than the opposite influence. The only way to hide this conclusion is censorship, witch hunts, and burning of heretics at stake. There is no scientific way to deny this clear conclusion from the data.

The comments in some of these articles that the greenhouse effect could still be important is just fog that the authors included in order for their "politically incorrect" scientific conclusions to get published. This fog was probably incorporated into these papers by reviewers-alarmists, but this fog makes no sense whatsoever.

It follows from an analysis of the data that the greenhouse effect couldn't have been too important at the multi-millenium timescale.

Appendix: Gore's lift

If you have seen Al Gore's movie, you may also remember the lift. He argued that because there has been a correlation between CO2 and the temperature during the glaciation cycles, the significant recent growth of CO2 may be directly translated to a huge warming.

But we already know that this prediction is falsified, either by understanding the opposite direction of the causal relationship, as explained above, or simply by looking at the basic numbers:

During the ice ages, the concentration was 180 ppm (parts per million) and it grew to 280 ppm or so during the (warm) interglacials. This increase by 100 ppm of CO2 was accompanied by 8 °C of warming or so. But the same increase of CO2 from 280 ppm in 1800 to 380 ppm in 2005 was only accompanied by the measured 0.7 °C warming or so (even if we assume that all of the observed warming is man-made), more than one order of magnitude smaller than 8 °C. We simply know that the warming caused by CO2 is at least 10 times smaller than Al Gore tries to suggest with his exercise.

Incidentally, if you care, after many centuries or a few millenia, the correlation between CO2 and the temperature will get restored again. But the details how it will happen are inconvenient, too: in a few centuries after we stop adding CO2 to the atmosphere, the oceans will absorb or "suck" most of the "excessive" CO2. Therefore, they will also undo the small warming by 1 °C or so that the excessive CO2 has caused. The oceans have a huge capacity.

Other likable climate articles on The Reference Frame

• January 2008 was the coldest month since 1994 (HadCRUT3)
• Christopher Monckton & warmers
• Temperature changed before CO₂ concentrations, not the other way around
• Intelligence Squared US debate: deniers beat alarmists
• Temperature CO_2 sensitivity is sublinear
• Correlation of sunspots and cosmic rays vs temperature
• 2006: a painful year for chicken little's
• 2006: colder than 2002 - 2005

Universities UK hate pure science and love politicized science

One can't certainly be swimming and relaxing the whole days.

The British socialist daily "The Guardian" has published what they think are the top 100 world-changing British scientific discoveries in the last 50 years.

Although there are many entries in this list that are good science (and technology and medicine), I think that the bulk of their list is another outrageous example of politicization of science, another example of misunderstanding of the truly important values and ideas, and another example of increasing influence and pressure of ignorant people who are not willing to think much on science.

Three sections out of nine are dedicated to health sciences. That may look too much to some but medicine is important, after all. However, there are much more serious problems with their list. Let me mention a couple of entries that I view as purely political ones and, from a scientific viewpoint, more or less worthless.

Most of the section 6 is a political dumping ground

• someone "found" that poverty is behind learning difficulties ;-)

What sort of top 100 discovery is this one? It's complete BS. Everyone who has common sense has always known that wealth can speed up learning. For centuries, the rich families were the most educated ones. Everyone who has observed the real world knows that there are also other reasons behind the problems in learning, especially innate aptitudes but also things like family circumstances - in sharp contradiction with the "discovery" of Richard Morris Titmuss who claims that family circumstances can't play any role.

This BS discovery was added purely because of left-wing bias. The authors of that list simply want to paint poverty, a natural state of affairs before the people establish the system that can increase wealth by a concentration of capital, as the cause of many other evils.

• Arthur Lewis' speculations on poverty

The previous one was not the only bogus discovery related to the interpretations of poverty. Arthur Lewis et al. studied how poverty emerges from a combination of markets and local agriculture. He apparently missed the fact that poverty is a natural state of affairs, and additional processes - requiring free markets but not only free markets - are necessary to accumulate wealth. What did Lewis exactly discover so important? As far as I can say, it's more or less pure propaganda.

• Amartya Sen and famines

Sure, there is also a third big "discovery" related to the interpretation of poverty. Sen - whom I actually know a bit because of my Marxist colleagues - concluded that famines appear not because of shortage of food but because people don't have money to buy the food. Wow. ;-) What this "discovery" is supposed to imply does not need any explanations. But one shouldn't forget that if the link between the money and the ability to buy things like food is broken, you should not be surprised that you can't buy toilet paper for months in a central European country in the 1980s, among many other things.

Of course, I can even give you the fourth "discovery" about the interpretation of poverty:

• Michael Rutter et al.

argued that schools in poor neighborhoods may be successful. Well, but they don't have to be, and usually they are not, even decades after Rutter's "breakthrough". I could also mention the fifth discovery related to a fight with poverty - proposals about the pension system by Peter Townsend and Brian Abel-Smith - but I choose not to discuss this discovery about poverty because even the liberals who read these lines could start to feel sick. Also,

• Kevin Bales counted the slaves.

His result was 27 million and it became a top 100 discovery in science. Are they joking? The precise number has no information value. It depends how you exactly define a slave. There is no God-given boundary between slaves and non-slaves. The number is just a political slogan. Some prostitutes are partially slaves, others often feel as slaves, too. They have contracts that force them to work under conditions that others would not like. They are upset. Sometimes they are rightfully upset. There is no objective way to decide whether they are slaves. The idea that people in the current complex world can be divided to slaves and non-slaves is another example of the left-wing inability to think about very elementary issues in the society and of a breathtaking naivite of neo-Marxist sociologists.

Why are they imagining that people can be sharply divided to exploited ones and un-exploited ones, instead of accepting that there are many ways how people can arrange their relationships? Because they are still dreaming about the ideal communist society where all relations between the people are simple, cows are sorted in regular boxes, and people are treated analogously: everyone must follow the same, very constraining rules and whoever does not follow these rules must either be a slave or his owner. They obviously learned nothing whatsoever from the fact that these egalitarian ideas have crippled nearly one half of the world for the last 50 years.

The quality of the remaining "discoveries" in section six is similar but I just chose some of them. Margaret Thatcher has introduced ideas and policies that have led to a clear strengthening of the British economy etc. and these policies - privatization, reduction of the power of the unions, and others - were clearly more world-changing than all the left-wing pseudodiscoveries listed above combined. Is it surprising that The Guardian can't include her? Even though I am a Thatcher fan, I would not include her discovery about the power of privatization among the top scientific discoveries - even though they have been experimentally proved - because I am less tasteless than my counterparts in The Guardian.

David Hazell has

• empowered nations and regions

while David Butler has "discovered"

• election swings. ;-)

Roughly 10 citations, and no comment. According to the committee, this discovery is on par with LCDs, holograms, or Magnetic Resonance Imaging.

Section seven - understanding ourselves

This section is mostly a junk, too. The first discovery is called

• Third way

because a certain Mr. Anthony Giddens proposed that we must invent a "third way", new political tools to respond to the new world blah blah blah. No third way has ever led to anything useful, the "third way" has become a motto for the political parties struggling for the least demanding voters (for example, Smer - "Direction Third Way" - in Slovakia whose membership in the European Socialists was just suspended is a proponent of a Third Way; they were punished for their new coalition with Slovak neo-Nazis who want to raze Budapest), and there is an overwhelming evidence that the ideology of Giddens and many others is just plain wrong. But The Guardian still counts it as a top 100 discovery.

• Alan John Percivale

has changed "our" perception of the war forever. He certainly did not change mine, but what is clear is that "our perceptions" are not science even if he changed them. It shouldn't have appeared in this list.

• War and peace

This "discovery" by Michael Howard cannot even be described by words. He "continues to study" whether peace will ever be possible. Complete junk. No results. And let me tell you that there will always be some conflicts as long as there are humans. This guy should return all the money that the taxpayers have ever paid him for producing this junk. Instead, he is chosen among top 100 U.K. discoverers.

• Debunking science

This is a really cute description of the work of Karl Popper: he was "shaping politics and debunking science". Although it might be insulting for Popper himself, it is certainly a very correct description of some recent people who refer to Popper's ideas because all of them are science-haters or, as they are called by similarly misled journalists, they are "debunkers of science".

Section eight - environment

Needless to say, this section is mostly garbage, too. The first top 100 discovery from this group is

• Gaia,

the idea that the Earth is a living organism. From a scientific viewpoint, this is a meaningless combination of words, much like the sentence "green ideas are sleeping furiously". Incidentally, the last sentence is more meaningful than it was 30 years ago - it means that the environmental movement is not using their brains.

But as they correctly say, Gaia helped to transform many people's (mis)understanding how the environment works. It has certainly helped to spread all the myths about the "ideal equilibrium", the completely flawed and thoroughly dumb idea that the Earth has been essentially constant in all respects and the lions, antelopes, insect, and volcanos were happily living in a perfect harmony until the evil humans have violated this "holy constancy".

• Hubert Lamb

was a name of a climatologist that was not known to me before, but Willie S. has explained me that it was my ignorance and he belonged among the top climate scientists. So I believe him that it is fair that he appeared in the list although my knowledge does not allow me to confirm it. There can be roughly one additional mis-judgement in this article - a guaranteed fair appraisal of all 100 discoveries would require a multi-day research. ;-) Rae Ann has noticed something that I initially missed: the discovery of possible

• long-term psychological effects of floods

is another top 100 discovery. Even though such an effect must be an obvious (but clearly not guaranteed) possibility to every kid in the kindergarden, its discovery is on equal footing with plane tectonics (the modern observational proofs of the continental drift).

Pure science

The only British discovery related to theoretical physics or mathematics or anything that requires a bit deeper quantitative thought that has made it to top 100 are Hawking and Penrose's

• singularity theorems.

After reading the gigantic pile of political excrements painted as "top discoveries" above, let us admit that one is not too many. Moreover, the singularity theorems might be interesting but counted by objective scientific measures such as the citations, they are six times less important than the Stephen Hawking et al. discoveries related to black hole thermodynamics and their evaporation or Michael Green et al. discoveries of the anomaly cancellation in string theory that has transformed theoretical physics for decades.

Where do they get their self-confidence to include discoveries that are, according to the experts, seven times less important than those that are omitted? What I think has happened was that the committee that was creating the list - primarily a committee of Marxist sociologists - decided that leftist sociology and closely related "discoveries" will get around 20 slots and theoretical physics (which also includes all of mathematics) 1 slot even though the opposite ratio would be a bit more reasonable.

Because they realized that it was not yet acceptable to mention no discovery of Hawking or no discovery of Penrose in the list of 100 major British scientific achievements of the last 100 years (because some people might still remember the names of Hawking and Penrose), they chose a paper that contained both names. Next time, when the political correctness - or perhaps the specter of the new communism - spoils the society even more than today, they will omit theoretical physics altogether.

What kind of trash is being served to the readers, particularly in the U.K., is really alarming, and you should not be surprised that cheap science-hating books are sold well in this troubled country that used to be a leader in physics and other sciences 150 years ago. Things are going to get even worse as science is disappearing from British classrooms and it is being replaced exactly by the kind of garbage that has dominated this article.

This is unfortunately a self-feeding process. The more idiots there will be among journalists and "academics" who compose similar lists, the more they will increase the relative representation of stupid ideas, and the more they will attract even dumber people and the harder it will be for everyone else to say anything that is reasonable. Once things get a wrong turn, things can't suddenly get better in a continuous fashion. British Academia has entered the quasi-Darwinian mode of survival of the biggest and dumbest commies - the ultimate dream of the politically correct people.

Czech hurricane

Figure 1: the eye of a Czech hurricane as seen on 6/29/2006

Kevin Vranes has nearly predicted that the global warming judgement day was coming to the Czech Republic. After a very cold May and a hot June, the Czech Republic had several days of rain last week. Right now, it is sunny again and I got a mild sunburn yesterday. No one in the Czech Republic has noticed the hurricane. The rains caused some floods at the upper portion of some rivers - a 60-year flood at one particular place - but there were no floods at the lower parts of the rivers, certainly not anything that could be compared for example to the floods in summer 2002.

I am pretty sure that we used to see these eyes on the satellite images many times when I was a kid. The only difference is that we were not being told that it meant the end of the world. Also, truth to be said, the Czechoslovak communists respected the U.S. president - Ronald Reagan - much more than the hysterical left-wing U.S. blogosphere respects the current president today.

I don't know whether the global leftists have learned anything from their miserable failures in the second world - but what is clear is that they became much worse and much less realistic in issues such as the environment, feminism, and security.

Thanks to WS for the hurricane tip.

Off-topic - murder: because this blog is again the number 1 Google hit for Mary Winkler, it is my duty to tell you that she killed her loving husband essentially because of $500 or $17,500 that she wasted from the family accounts on Nigerian and similar e-mail scams. Matthew Winkler did not like it - and he did not like how she was eating and walking either - so she had to shoot him with his gun because a divorce is impossible. But on the other hand, we must admit that she also said "I'm sorry" after the act.

Slovak politics: the European socialists have suspended the membership of a party for the first time in their history. The Slovak party "Smer sociálna demokrácia" - "Direction social democracy" was removed from the union technically because of their government with the far-right, anti-Hungarian "Slovak National Party" (SNS). (The former semi-dictator Mečiar is in the coalition, too.) The Czech prime minister Jiří Quimby Paroubek is the only European leftist leader who continues to support Robert Fico, the chairman of the populist party Smer. This shows both the inter-Czechoslovak friendship as well as the exceptionally bad taste of the Czechoslovak social democrats. ;-)

Nonsupersymmetric black holes: entropy

For more than twenty years since the Bekenstein-Hawking calculations of black hole thermodynamics, people were unsuccessfully trying to find a microscopic description of the entropy. Strominger and Vafa succeeded in early 1996 and explained the entropy of a special BPS black hole composed of D1-, D5-branes, and momentum. That was a breakthrough. The result agreed including the numerical constant. It had to agree and their main task was to find an example where the agreement can be proved, and check it.

Meanwhile, people have calculated the entropy of many black holes with 3 or 4 types of charges that are supersymmetric (and therefore extremal). An agreement was always found. People have also checked near-extremal black holes, and the microscopic stringy result agreed with the macroscopic prediction in all cases. Near-extremal black holes are black holes that differ from the extremal supersymmetric ones by epsilon and their parameters are expanded up to the leading order in epsilon.

Black holes with up to seven parameters describing various types of charges and angular momentum have been successfully checked. If the black holes are extremal or near-extremal, there are rigorous arguments based on supersymmetry that the entropy had to match if the theory is consistent, and indeed, they do match.

The corrections to the entropy of various black holes have been calculated to all orders; the recent Ooguri-Strominger-Vafa formula plays an important role in this direction of thinking. The successfully checked examples include black holes with unusual topologies such as black rings. The dependence on the charges knows about the exceptional groups and we encounter interesting mathematical structures such as the hyperdeterminant. A lot of other links with interesting mathematical structures and modular functions occured in the heterotic case.

What is interesting is that the full functional dependence on the parameters agrees even for many non-supersymmetric black holes. We have a new example: in their new preprint,

• Emparan and Horowitz

study the 4+1-dimensional Kaluza-Klein black hole embedded in M-theory in the most obvious fashion - by adding a six-torus. The entropy again agrees perfectly. I think that virtually everyone who has studied these things at the technical level would agree that we will no longer be shocked by such checks. The black hole entropy calculations in string theory are a success story and it is completely unreasonable to conjecture that a mismatch will suddenly be found when we look at another example.

Also, more or less everyone who has looked at these things will agree that string theory (with everything that is directly connected to it) is the only known framework - and probably the only mathematically possible framework - in which such a check of the black hole entropy can be successfully made. The analogous attempts to calculate the same things in various "competing theories" fail miserably.

In other words, only ignorants and stupid people are ready to humiliate the highly non-trivial constraints on a theory of quantum gravity imposed by the very consistency of the theory - for example, by an agreement between the microscopic and macroscopic formulae for black hole entropy. Words are easy; calculations are hard. Only ignorants can be preaching about many alternatives to string theory. If they were more than just cheap demagogues and authors of dumb books for undemanding readers, they would at leat try to find such an alternative. If they did it honestly, they would end up with the same conclusion as all of us:

There are no alternatives and the calculations of the microscopic origin of the black hole thermodynamical properties offer one obvious way to see why.

Columbia University crackpot joins Mark McCutcheon

On this blog, we have extensively discussed ethically problematic acts of a crackpot named Mark McCutcheon who has written a 1-star book "The Final Theory" that denies, among many other things, the existence of gravity acting both on the celestial as well as terrestrial bodies.

Because all the amazon.com reviews appeared at some moment in the past, we know that Mark McCutcheon has erased - or forced amazon.com to erase - at least 222 reviews, mostly one-star reviews. They were just inconvenient for the author and his somewhat immoral profits. The remaining 100 or so reviews incorrectly indicate that McCutcheon's worthless 1-star book deserves 5 stars.

I was just told that a lecturer in discipline from Columbia University - and the owner of the world's most active physics crackpots' discussion forum - who has written a 2-star book that everyone knows has joined Mark McCutcheon and made amazon.co.uk erase all reviews of his book - for example my 2-star review - except the 5-star reviews written by idiots most of whom have not read the book - and neither of whom has any idea about the content of the book. This kind of fraud leads to the average rating of this 2-star book to be displayed as 5 stars. Also, several 5-star reviews that were not deleted have been edited by a third party.

The author has personally confirmed that he has contacted amazon.co.uk with his desire to remove the "inappropriate" reviews - and he is quite obviously proud about it.

I think that the lecturer in discipline - and amazon.co.uk - should be ashamed for this immoral, despicable behavior. The lesson for all of us is clear: those who don't and can't accept the standard rules of making progress in science always follow the same procedures. Crackpots not only share some common errors in their thinking and they also love to criticize the existing science by their nonsensical pseudoarguments but they can never stand criticism - or peer-review - themselves.

This is one of many reasons why The Reference Frame will never accept the politically correct clichés that these people's voices are useful for science blah blah blah. The writing of these people is a completely worthless crap and any suggestion that it is something else is a result of fraud, ignorance, stupidity, censorship, and lies.

Bad guys form Slovak government

Exactly as we predicted, the coalition agreement in Slovakia was just signed by the following three guys:

• Robert Fico, a former communist and a leader of the left-wing populist party "Smer"
• Ján Slota, on behalf of the far-right Slovak National Party
• Vladimír Mečiar, the boss of HZDS (The Movement for Democratic Slovakia) and the former authoritarian prime minister

At www.sme.sk, visitors were asked what they think about the new government and 63% answered that they are thinking about emmigration. ;-) The figure probably should not be taken too serious but the sentiment should.

Summers era ended

Larry Ellison has just cancelled his $115 million gift to Harvard.

According to The Crimson, the official justification is exactly what The Reference Frame wrote some time ago:

• “Larry Ellison had an agreement with Larry Summers. Larry Summers’ departure from Harvard has changed that agreement,” said Bob Wynne, a spokesman for Oracle.

It is not surprising that The Reference Frame finds this explanation rather meaningful: additional $115 million has been added to the total cost of the numerous shameful decisions of the feminists and their allies at Harvard. Political correctness is an expensive beast, indeed.

And there are much more valuable things that we must pay because of PC and similar pernicious tendencies.

On the other hand, I think that it is equally fair if you hear from your humble correspondent that we have heard some signals that the true reason could be a bit different than what a spokesman for Oracle has told us. But this alternative explanation would not be so nice from the viewpoint of Oracle's image. ;-)