Saturday, February 28, 2009 ... Deutsch/Español/Related posts from blogosphere

Jonathan Krohn defines conservatism

Principles matter. The author of "Define Conservatism" will celebrate his 14th birthday tomorrow. Congratulations! ;-)

If America survives the coming socialist catastrophe, and be almost sure it will, its far future will be shining again.

Wikipedia: edit wars

I saw the following quote on Marco Frasca's blog:

"Great spirits have often encountered violent opposition from weak minds" - Albert Einstein
Marco dedicated it to string theorists which is nice but unnecessary because Einstein has done it himself. So I wondered why Marco chose this particular quote. And the comment thread answered the question.

Marco has apparently edited the article about Yang-Mills theory.

He incorporated some links to Smilga's book concerned with the classical solutions - but also his own papers i.e. some work that might potentially be interesting but it is probably not paramount for the subject; at least so far, it is not. Well, that's not what I call a preferred method how to edit Wikipedia. On the other hand, I don't think that all articles should be written by "neutral outsiders": it is very good for a writer to be familiar with a subject, too.

Wikipedia's articles are often very useful, informative, and reliable, but a sufficient number of sufficiently educated and informed yet neutral and co-operating editors usually underlies such a situation.

But Marco was surely not the only one who has done such a thing. However, Peter Woit just edited Wikipedia for the first time in his life. As you can expect with this unfriendly, uncreative, narrow-minded, and permanently negative individual, it wasn't exactly a useful contribution to Wikipedia - like thousands of articles and pictures contributed by your humble correspondent - but rather an edit war. Woit was instantly warned that he would be banned if he continued in the revert war: not bad for his first Wikipedia edit!

Woit's hypocrisy

While promotion of one's own articles is counterproductive, it is not a catastrophe because there is a whole Internet of other users who can fix it. More importantly, Woit's criticism is immensely hypocritical.

Thursday, February 26, 2009 ... Deutsch/Español/Related posts from blogosphere

Will the euro survive?

R.I.P., the Stability and Growth Pact

The eurozone shares a currency even though it doesn't quite share a federal government, or at least not a fully authoritative, functional, and dynamically elected one.

The currency should be protected by the Stability and Growth Pact, adopted in 1997. It forbids the member countries from exceeding 3%-of-GDP budget deficits and 60%-of-GDP national debts.

As President Klaus said last year (and earlier), the euro didn't have to pass any tests during the first decade of its existence. Many people were laughing but the situation may be changing. The "crisis" allowed many people to transform The Stability and Growth Pact into a worthless piece of paper in October 2008.

Ireland, Greece, Spain, France, Malta, and Latvia (with a currency peg) will have heavily broken the Pact next year. Ireland is expected to have 9% budget deficits at least for two years and its debt will jump from 24% above 60%.

In the past, Germany used to promote separate national fiscal policies. However, German finance minister Peer Steinbrück was the first one to suggest a "bailout" for Ireland, in order to save the country from "severe challenges" (Trichet's words) and a possible bankruptcy.

Richard Howard of Hayman predicts that Germany will prefer to save the money and it will leave the eurozone.

Soft landing, like this professional example on the Hudson river, would be better for Ireland.

The expected expansion of the eurozone's debt may be transformed into a full-fledged Italian style of living from the debts. Some countries may find the lack of the discipline of others irritating while others will feel constrained by the common rules and interest rates.

It is surely not unthinkable that the eurozone will start to decay in a couple of years. What do you think?

Škoda cars

Meanwhile, the Czech carmaker Škoda (in the Volkswagen Group) is going to resume the 5-day week since March in most buildings. In January 2009, the Škoda Superb sales were 7% above expectations. Some other Czech carmakers, like Czech Hyundai in Nošovice, are even planning to work on Saturday. ;-)

The increasing demand (for competitively priced cars) is supported by Western European subsidies to the buyers of new cars.

At the same moment, Barack Obama plans the 2009 budget deficit of 1,750 billion dollars, quadrupling the old record score. ;-) With 12.3% of the GDP, the U.S. couldn't join the eurozone (by a factor of 4.1). The deficit will be 1/2 of the budget: that sounds really honest. :-)

In 2007, the deficit was just 163 billion dollars, almost 11 times less, but Bush was constantly criticized by the liberals. The situation is different for comrade Obama, isn't it? He is allowed to create arbitrary deficits. The idea is that huge deficits can lower e.g. the weekly jobless claims - today at 667,000 - and revert the dropping GDP - it dropped by 6.2% annual rate in Q4 of 2008.

Except that deficits can't do such a thing.

Obama's socialist government has many other plans e.g. to rob the (relatively) rich. That shows his complete misunderstanding of the present situation. The problem is that the (relatively) rich - those who create (useful) job opportunities etc. - got much poorer (because of sinking equities etc.): the poorer people were not affected. The right social-engineering way to kickstart the economy would be just the opposite thing: try to pay money to the rich - those who own companies and stocks and who lost dearly.

History of Yang-Mills theory and wishful thinking

The readers of a notorious anti-physics blog are discussing the history of Yang-Mills theory. The basic historical facts about the fathers and grandfathers of non-Abelian gauge theory are not difficult to summarize:

  • the theory was almost completely constructed by Oskar Klein (TRF) in the late 1930s; it's because this superbright guy was able to learn some general lessons about gauge theories from the Kaluza-Klein theory he co-fathered; it was one of the early examples of string theory's ability to penetrate from the future into the past and give selected physicists an extraordinary ability to be ahead of everyone else
  • the theory was completely constructed by another superbright guy, Wolfgang Pauli, in the 1940s; but he didn't publish it because he was also able to "prove" that because of the new long-range forces, the theory was ruled out (of course, he knew neither the symmetry breaking nor the confinement)
  • the complete classical theory was published in 1954 by Yang and Mills but all the details of their physical motivation were incorrect (and they didn't know the Higgs mechanism and the confinement either)
The application of these non-Abelian gauge theories on reality arguably didn't make much progress between the 1930s and the late 1950s. Back in 1954, Yang and Mills had the following applications in mind:
  • like everyone else, they dreamed about describing the strong interactions - which was so mysterious
  • they decided that the SU(2) isospin had to be a local symmetry.
As you know, the latter point rather quickly led to the electroweak theory - a new description of the weak and electromagnetic interactions with an SU(2), isospin-like (but chirally coupled) factor of its gauge group. Tasked by his advisor Julian Schwinger, Sheldon Glashow (and others) began to publish papers about this SU(2) origin of the weak interactions in 1956, just two years after the 1954 Yang-Mills paper.
Off-topic: Click the Chrome logo to download the newest Google Chrome
On the other hand, the application of Yang-Mills theory to the strong interactions had to wait for nearly 20 more years (or 35 years since Klein's insights), until the early 1970s. The gauge group had to be changed (and constructed from the scratch), it had to be disconnected from the isospin because the isospin is just an approximate global symmetry of the strong force, and asymptotic freedom had to be understood.

You can see that the two points listed above - the dream of Yang and Mills to explain the strong force; and their decision to gauge the isospin - have nothing to do with each other. That's why the statement that they constructed their theory to describe the strong force is untrue. They were dreaming about an explanation of the strong force but every detail they did with their theory was only relevant for a better description of the weak force!

Wednesday, February 25, 2009 ... Deutsch/Español/Related posts from blogosphere

Nir Shaviv: Solar fluctuations are amplified

In this dose of skeptical peer-reviewed climatological literature, we follow a kind recommendation by Werdna and look to Journal of Geophysical Research, Space Physics. Nir Shaviv wrote an article called

Using the oceans as a calorimeter to quantify the solar radiative forcing.
By using three independent records linked to the heat in the world's oceans, he deduces that a mostly unknown mechanism amplifies the total radiative forcing connected with 11-year solar cycles by a factor between 5 and 7.
CO2 Science story
In other words, the Sun is much more important for the energy budget than what you would think by looking at the small variations of the total power of our beloved star.

Tuesday, February 24, 2009 ... Deutsch/Español/Related posts from blogosphere

Czech National Bank debunks lies about the Czech economy in the Western liberal media

The Czech National Bank just reacted to some incredibly idiotic articles written in some of the Western media, including the Financial Times and the Economist.

The situation is that the media have written that the Czech economy is in a bad shape while it is in a good shape, to say the least.

With the new flat tax and its low rate, the country has become a tax paradise, too. By the way, the Czech economy grew in every quarter so far, including Q4 of 2008: we have seen no recession so far and be sure that there are not too many countries that can boast the same record.

Programming and internet paradigms

Almost everyone in the civilized societies - including my broader family - is using computers and the Internet these days.

However, one can see that the people who were introduced to computers as "users" have a very different type of thinking about the nature and purpose of computer programs than those of us who have looked at computers from different perspectives than just "users".

The history

But I would like to write a more general text about these matters.

Let me begin in the 1980s. As kids, we would attend "SMT" - the station of young technologists. Around 1982, our computer club owned an Ohio Scientific computer with a 6502 microprocessor: you might find this brand surprising in the communist Czechoslovakia but it was there anyway - even though one of our popular instructors, nicknamed the Bear, was the son of the Western Bohemian regional (or Pilsner municipal?) communist boss. ;-)

Supreme Master presents James Hansen

James Hansen's message to Supreme Master TV viewers is be veg, go green, save the planet. The best action you can make to reduce carbon emissions is vegatarianism, NASA climate chief says.

Well, as Penny of TBBT said, I am a vegetarian except for steaks. I love steaks. :-) Never more.

Update: The veg requests are no longer fictitious dreams in the world of fantasy.

The Massachusetts General Hospital in Boston, a building whose shape I am intimately familiar with (from the outside), was requested to serve exclusively vegetarian meals to the patients.

So far, the letter is only subscribed by an NGO of lunatics but others may be eager to join, like in so many cases and the NGO claims that "Britain" is already preparing such a plan for all hospitals.

You can also be veg and join this new religious cult. Alternatively, you may join a Facebook group

Facebook: fire James Hansen
attempting to remove the religious bigot from the leadership of the scientific institution where similar obsessed people should be given absolutely no room to oxidate.

Monday, February 23, 2009 ... Deutsch/Español/Related posts from blogosphere

Dualities vs singularities

A decade ago, when we wrote Dualities vs Singularities (PDF), I obviously had to be afraid of Mathematica. Otherwise I would have easily drawn diagrams similar to the following:

Click to zoom in. It is kind of pretty. But what does it show? I must tell you a few words.

Take the 11-dimensional M-theory and compactify it on a rectangular k-torus with no C-field. The shape of the torus is described by "k" radii,

{exp(p1), exp(p2), ..., exp(pk)}
times the Planck length (or more precisely, the self-dual radius under a U-duality described later). It is useful to write the radii as exponentials because the logarithms, "p_i", behave linearly under the multiplication of the radii and their powers.

And when you perform U-dualities, there's a lot of multiplication of radii by powers of other (or the same) radii. The "p_i" coordinates naturally go from "-infinity" to "+infinity".

The question was which values of the vectors "p" describe a physical situation whose rough behavior is well understood and where we have a natural perturbative expansion. For M-theory on tori, there are only three such descriptions:
  • M-theory: on a large torus in Planck units (11D SUGRA etc.): BLUE
  • Type IIA string theory: weakly coupled on a large torus in string units: PURPLE
  • Type IIB string theory: weakly coupled on a large torus in string units: BLACK
Various inequalities for linear functions of "p_i" describe which conditions have to be satisfied for you to have each of these descriptions. Permutations of "p_i" don't matter. For example, if the smallest "p_i" is (still) positive, then you are in the blue M-theoretical region.

Sunday, February 22, 2009 ... Deutsch/Español/Related posts from blogosphere

Fermi (GLAST) almost kills all Lorentz violating theories

Update: See Fermi kills all Lorentz-violating theories for a newer, stronger result.

In September 2008, a huge gamma ray burst (GRB), GRB 080916C just below the star Chi Carinae, could have been seen in the southern sky from the Earth. Fortunately, Fermi (formerly known as GLAST, TRF search) was actually there to see it. And three days ago, the paper announcing the good news was released:
Symmetry magazine, BBC
Fermi press release
Science ExpressOrdinary Science Magazine (reprinted in March 2009)
The gamma rays were arriving during a 16-second interval. Various frequencies tend to come earlier or later.

The explosion is a complicated event and it is clear that different photons are born at different places and different moments, which may explain the lag. However, it is also conceivable that the speed of light is different for different frequencies.

Can we decide what is the real origin? Yes, we can. If the reason is a frequency-dependent speed of light, the lags will be longer for GRBs that are further from us.

The new huge GRB shows that the contribution to the lag from a variable speed of light must be very small - because the spectrum of the burst precisely follows a universal spectral curve expected from the internal dynamics.

In this way, the measurement sets the best bounds on Lorentz violation we have so far. In the parametrization popular among the Lorentz-violating self-described "quantum gravity theorists", the typical scale where the Lorentz violation starts to be big must be above 1/10 of the Planck mass. Everything below this gigantic mass scale has been proven to respect the Lorentz symmetry, if you wish.

As you can see, we're almost there.

Fermi should be able to see a sufficient collection of GRBs at various distances to improve the accuracy and allow us to separate the "complexity of a GRB" and "Lorentz-violating" contributions to the lag. It is extremely likely that in a few years, it will be able to rule out all existing theories of quantum gravity except for string theory because all of them predict some kind of Lorentz violation that becomes large near the Planck scale.

Saturday, February 21, 2009 ... Deutsch/Español/Related posts from blogosphere

Man-made collapse of Arctic ice

Five days ago, Anthony Watts noticed a stunning decrease of the Arctic sea ice area in one of the sources that monitor this quantity.

The weekly decrease of the anomaly was about 5 times faster than the typical weekly change of the same anomaly in the past. So the unusual development was a five-sigma effect, something that shouldn't occur by chance.

Unless you believe in miracles, tipping points, extraterrestrial aliens, or catastrophic global warming, it should have been clear to you that the graph was a result of a failure or a mistake. Indeed, two days later, NSIDC confirmed that it was the case.

But Cryosphere Today is delayed. So only yesterday, we had the the opportunity to see the actual picture, as Anthony Watts pointed out. Cryosphere Today actually offers the whole maps which are much more interesting than a graph. Here it is, clear as sky:

Within 24 hours, four huge (black) holes developed near the North Pole. Half a million squared kilometers of ice were lost. The missing ice is nicely symmetric and carries the fingerprint of the human murderous acts against Ms Gaia.

If you look closer into the (black) holes, you will find a rather big text over there. It says "coal power plants are death trains in Auschwitz" - just like the popular prophet likes to say and pray. The debate is over: the industry is guilty! ;-)

More seriously, you can actually see the shape of the SSM/I sensor of the DMSP satellite. It looks (or looked) like it may have 12 arms or so and something was damaged near 2 arms. Sadly, ClimateAudit.ORG also seems to be down, for reasons that could be related to hardware.

Relativistic optical effects

Update: For general relativistic optical effects, see Optical effects near black holes
Special relativity makes things "being" Lorentz-contracted, processes "are" affected by dilatation, relativity of simultaneity, and there are other effects: see the visualization in Relativistic phobia. But what you "see" at relativistic speeds is a different question because the delay of the light signals has to be incorporated.

Relativistic aberration, Doppler effect, and modified intensity profiles are important issues. However, spheres always look spherical: the Earth at the end is pretty funny.

Via Antony Searle (see to view a couple of relativistic pictures). With QuickTime, you may also watch
Through Einstein's Eyes
Relativistic rollercoasters and other things are included: wait until the movie is downloaded. Even more impressively, you may download a pretty new Win/Mac program,
Real Time Relativity (download).
Updating your DirectX 9 might be necessary if you're getting a dx* error message. Vista users: don't be afraid, the update won't damage your DirectX 10.

Beautiful car races (in full screen resolution) with relativistic effects are ready for you.

A relativistic car race is getting started. Click to zoom in.

When you start to accelerate, objects in front of you initially seem to drift away from you. They become more spherical, too: a flat plane in front of you looks pretty much like a sphere: it's not a coincidence that these visual effects remind you of the Möbius transformation movie: locally, SO(3,1)=SL(2,C), after all.

That's no coincidence at all. Roger Penrose could explain you how these transformations affect the light rays - twistors are great, too. ;-)

Friday, February 20, 2009 ... Deutsch/Español/Related posts from blogosphere

A random vibrating string

Click the yellow picture twice to see an animation (2 MB). Sorry, the picture is kind of rotating because I forgot 1/2 of the modes. But all the other qualitative features are OK. Update: Fine, people couldn't live without it, so here you have the animation with all modes which is not rotating.

La Griffe du Lion: the universal math sex gap

In December, La Griffe du Lion (TRF search) wrote another brilliant article about the differences between sexes in their innate math aptitude. I only managed to read it now:

The math sex gap revisited: a theory of everyone
She or more likely he settles some questions raised by two recent papers about the gap that were written in La La Land (that's a meta-country where egalitarianism is a mandatory axiom of all their research).

The first paper that La Griffe du Lion clarifies was written by veteran feminist author
Janet Hyde (click)
and we have already discusses it: she claimed that the math gap between the sexes has evaporated. Lion's conclusions are pretty much identical to ours when he or she writes that
  • she uses tests with small children for which the gap has not yet fully blossomed
  • the tests are too simple and only measure the ability to understand basic things
  • she only talks about the mean differences, not the ratios of the variances; the latter are more important in highly selective contexts.
Emancipation vs math sex gap

However, La Griffe du Lion also talks about another paper written by four economists led by Paola Sapienza,
Culture, gender, math (click, PDF).
On their visit to La La Land, the authors argued that the math sex gap decreases in countries where women are more emancipated. La Griffe du Lion confirms that the correlation exists but he also proves that the origin of the correlation is completely different than the four authors suggested. But he shows much more than that.

He provides us with the evidence that the mean difference and the ratio of variances between the male and female distributions of math talent is universal for all nations in the world. The first graph that I will reproduce shows the percentage of boys and girls in different countries who were able to pass PISA tests at level 5 in 2003 and 2006.

This personal achievement pretty much means that the people are above the 85th percentile of the general population, i.e. that they're more skillful in math than at least 85% of the population. Here is the graph:

Click or shift-click to zoom in. Note that in 2006, the Czech Republic became the country that deviates from the interpolating blue line in the upward directions most intensely among all countries. Three years ago, we had the smartest girls, if you wish ;-), but their percentage at level 5 was still below the boys' percentage.

In 2006, the Czech girls were relatively the smartest ones in the world despite (or partly because?) the fact that Czechia's politically correct "GGI" index of emancipation, 0.6712, was the second lowest one after Japan ("second most discriminatory") among all the 12 best-scoring countries (where Czechia and Japan belong, together with Germany, Austria, Australia, New Zealand, Switzerland, Canada, Netherlands, Finland, Belgium, and Korea).

Thursday, February 19, 2009 ... Deutsch/Español/Related posts from blogosphere

Eigenvalues in Antarctica

I just read some ClimateAudit.ORG articles about

Principal components in Antarctica (part 2)
and reproduced some of the basic findings. Let me start with some results; I will explain what we're doing later in the text.

This is the PC1 visualized by my favorite Voronoi diagrams. Finally, you should also see two more diagrams of this kind, namely PC2 and PC3. There are no other PCs! What the hell is your humble correspondent talking about?

Fifty megabytes of junk

A few weeks ago, Nature printed a paper by Steig et al. about the temperatures in Antarctica. Michael "hockey stick" Mann is among the authors. Curiously enough, the data used in the paper are publicly available:
Steig's Nature 2009 website
The page above contains links to various files such as:
  • Tir_lats.txt (latitudes)
  • Tir_lons.txt (longitudes)
  • ant_recon.txt (temperatures)
The first two files are very short and describe the latitudes and longitudes (in degrees) of 5509 points in Antarctica. The third file is much bigger: it is about 50 MB long and it describes the temperatures for each "station" (5509 columns) in each month (600 rows corresponding to a recent 50-year period).

MEPs boo Klaus's call for free speech in EU

Bruno Waterfield, a blogger with The Telegraph, thinks that today's speech in the European Parliament, by Czech President Klaus, was the best one that was ever given over there.

Full speech of Václav Klaus (text, click)
Václav Klaus analyzed the democratic deficit of the EU, the importance of free speech and our sad experience with its suppression, the political origins of the ongoing economic downturn, the Treaty of Lisbon, many possible future directions of the EU, and other topics. Many MEPs were standing and applauding while others were booing and leaving. ;-)

See the last 5 minutes of the speech (in Czech), to get an idea about the stormy atmosphere. Go to 2:00:00 here for the full video (direct link for Windows Media Player).
YouTube playlist (also with English translation)
Most people in the room agree with Klaus but that's only because most of the deputies seem to be already gone. :-)

Klaus said that the economic downturns are like a flu: if you don't cure it, it takes 7 days. If you do, it takes a week. He was also surprised that Bastiat's famous fictitious petition from the 19th century - a request by candle producers who wanted to be protected by the government against an unfairly advantaged competitor, the Sun - became real in the EU's decision from November 2008 to add 60% tariffs on Chinese candles.

Avril Doyle, an Irish MEP, became the ultimate Nancy Hopkins of the room - the best representative of the second group from the previous sentence. With her voice trembling and screeching, she defined debate as a "recipe for chaos". Nice, indeed! Experimental evidence is always helpful to strengthen a theorist's point. :-)

Are AdS/QCD and AdS/CMT relevant for unification?

Download Google Chrome media outlets recently informed about the progress in AdS/QCD and AdS/CMT, methods to use Maldacena's holographic correspondence (AdS/CFT) to transfer our knowledge and results between string theory and gravity on one side - and nuclear physics or condensed matter on the other side.

Because nuclear physics and condensed matter physics seem to be different disciplines than high-energy physics and quantum gravity, many people naturally ask whether we're talking about the "same string theory" in both cases. If you're impatient, the answer is Yes, of course. There is only one string theory.

But many readers are hopefully more patient, so let us look at some issues in more detail.

The disk on the picture above - see hyperbolic cows for a similar picture - represents the Poincaré disk which is the Euclidean edition of an anti de Sitter space (AdS). If you want to know, the disk is EAdS2 and if you add the vertical time coordinate and assume that it has time-like signature, the resulting cylinder may be called AdS3. Several general aspects of the picture are worth noticing.
  1. All the bats seem to have the right shape; none of their aspect ratios ever gets extremely distorted; we say that the cylinder is "conformally equivalent" to the AdS space.
  2. There are infinitely many bats: the AdS proper volume is infinite.
  3. The disk (or cylinder) has a boundary; this boundary is surrounded by infinitely many small bats.
In general, Maldacena's holographic correspondence implies that a gravitational theory of some "bats" (degrees of freedom) inside the cylinder (a theory that includes black holes and other objects predicted by string theory, which usually includes strings and branes) is equivalent to a non-gravitational theory on the boundary. Note that we are talking about the exact equivalence of two theories; one of them is gravitating and the other is not; the spacetime dimension in the gravitating theory is higher by one.
Commercial break: Stanleyfest at KITP, Santa Barbara. Fascinating talks about Mandelstam and physics. Polchinski's talk is really inspiring and funny. Via Dmitry Podolsky.
In string/M-theory, the equivalence between type IIB string theory on AdS5 x S5 and N=4 gauge theory on R x S3 is the most popular and the most well-established example. This equivalence has profound implications for our understanding of the structure of string/M-theory.

Wednesday, February 18, 2009 ... Deutsch/Español/Related posts from blogosphere

The importance of stupidity in scientific research

N. Sriram has brought my attention to a cute essay by Martin Schwartz in Journal of Cell Science,

The importance of stupidity in scientific research
The author argues that it is very important for scientist to like the feeling of being stupid - either not knowing things because no one knows them and they wait to be discovered; or not knowing certain things because one's talents are different.

Schwartz also thinks that exams must push the student to the very boundary of ignorance.

Obama's socialism: USSA?

Two days ago, Newsweek wrote that "We Are All Socialists Now" in the title and mentioned that "Barack Obama sounds more like the president of France every day". The new recovery package looks like a Nationalization Act, especially if you notice that salaries are going to be capped and many other things will be centrally controlled.

Google News contains 4,000 hits with the words Obama and socialism. Add one million hits at Blog Search.

Simeon Hellerman: a proof of weak gravity conjecture

I am convinced that the best hep-th paper today is the first one,

Simeon Hellerman: A universal inequality for CFT and quantum gravity (PDF).
Simeon proves an inequality that may be interpreted as a special case of the weak gravity conjecture, namely that the lightest state in a quantum theory of gravity can't be heavier than a certain value proportional to the Planck mass.

To study 3D gravity in AdS space, he looks at the dual 2D CFTs instead. He assumes no supersymmetry, factorization, strings, or semiclassical gravity. Nevertheless, unitarity and modular invariance (yes, I am a bit uncertain whether he should use the normal "worldsheet" modular invariance for boundary CFTs) is enough for him to prove that there must exist a non-trivial operator whose dimension is smaller than a certain bound. For factorized CFTs, his inequality simplifies.

But I think it's kind of amusing to mention his "real" inequality that he could derive for a general CFT. The dimension of the lightest non-identity operator has to be smaller than
Delta < (cL+cR)/12+0.4736949789...
Whenever an AdS/CFT dictionary is possible, it means that the lightest state must be lighter than
M < 1/4GN + 0.47369/L
where L is the AdS3 radius and Newton's constant has the dimension of length in 3D. If you care what the crazy numerical constant is, it actually equals
0.47...=[12-Pi+(13 Pi-12)*exp(-2 Pi)] /
/ [6 Pi(1-exp(-2 Pi)]
The 1/4G part of the mass has been found to be special by Ashtekar and Varadarajan in 1994 although they couldn't offer a real "inequality" of Simeon's type. The 0.47 part is new and Simeon seems to be pretty serious about it, indicating that it can be saturated by some very special (or degenerate) CFTs. However, in the conclusions, he raises a suspicion that the bound can be improved which means that the old one couldn't be saturated. ;-) If you look at the formula for the numerical constant and imagine that it should be a dimension, the CFT has to be really strange (at least for a newbie). The strange numerical constant becomes even weirder in the bulk.

In the flat space limit, when the 0.47 terms are neglected, Simeon's upper bound is twice the classical mass of the lightest BTZ black hole (the latter is 1/8G).

I deliberately added the word "classical" to make this statement clear from the very beginning - because otherwise you could ask why he couldn't improve his bound to 1/8G. The formula 1/8G for the BTZ mass is classical and is going to be modified by quantum corrections. Simeon has shown that even if you include all such corrections, the lightest object can't be heavier than twice the classical lightest BTZ mass (but the lightest object can be a "different one").

Tuesday, February 17, 2009 ... Deutsch/Español/Related posts from blogosphere

Václav Klaus: The unbearable inability to learn

When communism ended (and I deliberately like to say that it was a collapse, not a defeat), it seemed that the ideas and institutions of that system were so thoroughly discredited that they couldn't return in any foreseeable future. And it seemed that no person could possibly - without blushing - dare to publicly defend them.

It seemed unreasonable to expect that people would prefer to trust the state instead of the markets once again; that they would believe that one can distribute more wealth than what is being produced; that people have a right for high living standards rather than that they must deserve them; that an arbitrarily lustrous doctrine is more important than the human freedom; that the wisdom of the anointed is more than the knowledge of the "ordinary" people.

Who was naive

However, we were not quite naive. During the last two decades, many of us were warning that those attitudes were only partially abandoned in the post-communist part of the world (and some third-world countries), that even those countries were quickly depleting the initial momentum, and that the "first" world was seeing no development of this kind at all.

Haaretz about Nir Shaviv

On Saturday, Haaretz.COM printed a pretty inspiring story about Nir Shaviv. The article offers you anecdotes about his scientific family, science-loaded childhood, and the present - e.g. that the librarians often ask Prof Shaviv to show his student ID (I've experienced similar things haha).

But the text is primarily about cosmoclimatology and its sociology. Recall that the cosmic rays help to create clouds and cool the atmosphere.

When they - Nir Shaviv and Ján Veizer - realized that 450 million years ago, when the CO2 concentrations were much much higher than today, the Earth was colder than today, there existed all kinds of pressures to get rid of the result. But when their cosmic ray graphs at this time scale matched the reconstructed temperature, the situation changed.

Without quoting his name, Shaviv mentions the cruel attacks by a nasty German eco-Nazi called Stefan Rahmstorf that they had to face for a while. When Shaviv decided to reply to hostile press releases by Rahmstorf, the German greenshirt threatened to sue Shaviv for copyright violation. These activists always tend to act in this immoral way. They don't consider the standard mechanisms of science to be "fair" enough, i.e. green enough.

Monday, February 16, 2009 ... Deutsch/Español/Related posts from blogosphere

Ernst Mach: a birthday

Ernst Mach was born on February 18th, 1838, in Greater Brno, Moravia, Czech Lands, Austria-Hungary. He was my territorial countrymate, if you wish, but no Czech would ever consider Ernst Mach to be a Czech guy.

His father was a tutor. Ernst studied and worked in Prague, Vienna, and various other places in the monarchy.

He became well-known for some rather rudimentary research of acoustics: the Mach number is the speed of an object divided by the speed of sound (that's not too hard). He investigated shock waves and similar effects related to the Mach number (together with his son who has made much more specific contributions with his interferometers and similar gadgets).

Ernst Mach also knew something about physiology/medicine and spent quite some time with psycho-physics - various questions what we're able to see or hear or smell and how the brain roughly deals with the information. Mach bands are a good example of an optical illusion he discovered:

The image above only includes a smooth gradient in the middle but your eyes probably think that there are two discrete strips in the middle of the picture.

Mach and philosophy of science

Clearly, the contributions above were not terribly deep and Mach is primarily remembered as a philosopher of science. His philosophy of science was bizarre, to say the least. First of all, he promoted his own idiosyncratic version of phenomenalism. According to this philosophy, only sensations, and not physical objects, are real.

Saturday, February 14, 2009 ... Deutsch/Español/Related posts from blogosphere

Milton Friedman's F-twist

The left-wing blogosphere has apparently chosen Milton Friedman (Nobel memorial prize in economics, 1976) as their target of the month.

CommunistSocialistSwine copies an article by a Brad DeLong. Although it is very clear that DeLong understands the basic structure of Friedman's deep monetarist ideas, he describes Friedman in a hostile way, without having any evidence against his ideas.

Friedman has understood that the money supply was the only major "central" parameter that an economy based on money seems to depend upon.

A central bank, ideally independent from the government, should keep the money supply pretty much constant, in order to avoid inflation or downturns caused by deflation. The economy is optimized when all other parameters (and decisions about the allocation of resources) are left to the invisible hand of the free markets - so the optimal way to fight deflation or a plummeting money supply is to "throw the money from the helicopters" while the right way to fight inflation is simply to stop printing the banknotes.

The history of the economies shows that Friedman was pretty much right on the money but his irrational foes can never be convinced by any arguments. They even try to sling mud on the Chilean economy, the country that adopted the liberal, monetarist policies in the 1970s before it saw the miracle of Chile that allowed the country (blue line on the graph) to double its GDP, relatively to the South American average (red line), and become the clear leader of the subcontinent.

Charles Wilson: 140th birthday

Charles Thomson Rees Wilson was born in Scotland on February 14th, 1869. Although he studied biology, planning to become a physician, he soon became interested in meteorology.

In 1893, he began to investigate clouds and their properties. Some 1893 observations of cloud formation led him to design his own experiments in Cambridge. He was able to create cloud trails in water vapors by ions and radiation.

Friday, February 13, 2009 ... Deutsch/Español/Related posts from blogosphere

Some XC skiing

Sorry, the apparent break is caused by our 20+ kilometers long cross-country skiing trip across the Brdy Hills, a few miles from the U.S. radar base. We started at Chynín. Blogging will resume soon.

Progress in neuroscience

A simple scheme of female thinking has been found.

Thursday, February 12, 2009 ... Deutsch/Español/Related posts from blogosphere

Klaus: Europe, environmentalism and the current economic crisis: a contrarian view

Let me put it into this frame:

Charles Darwin: 200th birthday

Today, Charles Darwin would celebrate his 200th birthday. Yes, he is only seven on this picture.

One of the greatest scientists of all time was born to a rich doctor and financier, Robert Darwin, and his wife, Susannah née Wedgwood, on February 12th, 1809. Mysteriously enough, Abraham Lincoln was born on the very same day, so we celebrate his 200th anniversary today, too. Happy birthday, Abraham!

As everyone knows, Darwin refined some pre-existing memes about the gradual development of life by finding the crucial mechanism, natural selection, that allows Nature to ramify its diverse tree of ever more viable life forms.

Today, his discovery sounds as an obvious theoretical idea: we view it as the only possible scenario that can reconcile the origin of life with the geological and cosmological history of the Earth and the Universe that we learned by other methods.

But Darwin had to do a lot of phenomenology to find evidence supporting his idea. So he studied the differences between birds and tortoises on the Galápagos Islands and elsewhere. He was also a practician: largely because he knew that good genes were important, he married his cousin. ;-)

At any rate, the qualitative gap between humans and animals has evaporated, to dismay of believers across the world. Humans have evolved from creatures that we would surely call "monkeys" if we saw them, even though they were not identical to the existing monkey species - our distant cousins such as chimps, gorillas, and global warming alarmists.

His discovery didn't make religion impossible but it helped to make irreligion possible. Miracles were no longer needed to explain the beauty and diversity of plants and animals and the unity of all living forms was revealed in its naked entirety. Happy birthday, Charles.

U.S., Russian sattellites crash

Soyuz-Apollo, collider edition

It's been the first time when full-fledged satellites collided. Both were communication satellites - one ton (Kozmos 2251) against half a ton (Iridium LLC, both above Siberia). The Russian vehicle won, turning Iridium into smoke, but its own fate wasn't much better. ;-)

The debris may be a threat to ISS and other objects. When they determine the coordinates of the dangerous pieces, ISS may get ready for a slalom!

See also: The New York Times
So far, the density of objects in the orbit has been low enough that no one has bothered to write down any traffic rules for the satellites. I am afraid that this will become necessary in the future.

An order-of-magnitude estimate follows. Feel free to fix it if it is unrealistic.

Wednesday, February 11, 2009 ... Deutsch/Español/Related posts from blogosphere

A fun story of a zeta-function identity

Off-topic: Click the Chrome logo to download the newest Google Chrome

The previous article about the topic was:
Zeta-function regularization
When I was a sophomore in Prague, in 1993 or 1994, Dr Ctirad Klimčík (Luminy, France, a specialist in integrability) gave a nice colloquium about string theory. At that time, I had already studied a lot of stringy NPB papers and preprints on the arXiv but his talk was new and inspiring, anyway.

One of the technicalities he emphasized was the zeta-function regularization. More concretely, the sum of positive integers equals -1/12, he said. He convinced me completely so I wrote an article into our student journal, Pictures of Yellow Roses, with a new proof of the identity based on Taylor expansions with respect to a new parameter of a generalized zeta function, a shift.

One year later or so, in October 1995, I submitted a preprint about these issues: a dedication to my Christian ex-GF was included, much like a brand new system to label preprints, starting from HEP-UK-0001 (I've never abandoned it; UK stands for Charles University in Czech). It generalized the "sum of integers equals -1/12" in various ways and used it to calculate commutators of Virasoro operators in string theory - and even in free fermionic models. ;-) You may see that my English got a little bit more authentic since 1995.

Tuesday, February 10, 2009 ... Deutsch/Español/Related posts from blogosphere

Covariant M(atrix) Theory

Matsuo Sato (PDF) proposes a new approach to the covariant M(atrix) theory.

Tsukuba, the home to the 3/4 of the IKKT model.

As the author's name indicates, Sato loves the Japanese (IKKT) matrix model for type IIB string theory. My opinion whether this matrix model is correct and nontrivially incorporates all physical observables of type IIB string theory has changed many times throughout those 12 years. It's been one of the most fluctuating yet potentially "answerable" questions about M(atrix) theory.

I haven't heard any convincing, complete answers to this question and my current opinion about it is fuzzy.

While the timeless IKKT matrix model formally comes from the action of many D-instantons, and its bosonic part involves a quartic expression in "X", namely a squared commutator, Matsuo Sato proposes a similar timeless matrix model whose bosonic part is a sixth-order expression in "X", a sum of squared triple commutators.

This should be seen as an imported idea from the recent membrane minirevolution that has dealt with 3-algebras. While the squared triple commutator defines the bosonic part of the action, he guesses that a Psi.[X,X,Psi] term completes the fermionic terms. He realizes that it's important to check SUSY but he hasn't done so.

The Maternal Capacitance

Episode 2x15 of The Big Bang Theory:

A disastrous visit of Leonard's mother paradoxically brings Leonard closer to Penny (and some bottles and lemon) again. Well, for a while.

Also, I can't believe Sheldon likes Ms Hofstadter. She reminds me of Leslie Winkle more than himself. ;-) Otherwise, her hypotheses about the childhood are surely worth thinking about.

This episode had the highest rating, 8.1, so far, with the share being 12, also a record. The number of viewers seems to be safely above 10 million at this moment.

Protectionism: Sarkozy vs Topolánek

The Czech EU presidency - which has so far been "excellent" according to Barroso and others (and has improved the Czech government's approval rate) - currently has to deal with some "bad guys" of Europe. It turns out that the worst guy in Europe happens to be Nicolas Sarkozy, the French president. He decided to promote protectionism in the most brutal way imaginable.

Xinhua quotes him as saying the following thing on French TV:

"It is justifiable if a factory of Renault is built in India so that Renault cars may be sold to the Indians. But it is not justifiable if a factory of a certain producer, without citing anyone, is built in the Czech Republic and its cars are sold in France."
Have I heard you correctly, Mr Sarkozy? Is it not acceptable for you if PSA Peugeot Citroen opens a plant in another, more efficient region of the European Union and sells the cars in the whole European Union, namely in Kolín (Czech Cologne) where a joint plant of Peugeot/Citroen and Toyota operates?

I simply can't believe that a superficially right-wing and pan-European president could have said something along these lines. It's stunning. Thank God that Sarkozy's approval rate in France just dropped to a record low, 36 percent. The right to produce cars and sell cars in different countries is a basic assumption of the international trade that should be respected for all pairs of countries. But right now, we are even talking about two countries in the same de facto confederation, the European Union.

Moreover, Sarkozy is among the people who would love to transform the EU into a federal state. But does he want to ban the export of cars from one region of this would-be federal state into another? Needless to say, his words were not only a radical defense of protectionism - which is not really popular in Czechia as a matter of principle - but also an attack against the rights and interests of the Czech Republic.

Monday, February 09, 2009 ... Deutsch/Español/Related posts from blogosphere

Flynn: my effect went into reverse in the U.K.

Great Britain has given the world many precious gifts, including mechanics, modern electromagnetism, and evolutionary biology. As a colonial superpower, this country of dry humor and higher classes has transformed many of its former colonies into lands of current or future prosperity.

But in the recent years, we have seen many warning signs. See e.g.

U.K. universities hate pure science and love political science
Physics fades from U.K. classrooms
James Flynn (New Zealand), one of the most leading IQ experts in the world, has found evidence that the intelligence as measured by the IQ tests is generally increasing from generation to generation. The reasons behind this Flynn effect have remained controversial.

However, Steve Sailer just informed us about a new study by James Flynn that indicates that the Flynn effect has changed its direction in Great Britain.
The Telegraph
The IQ of 14-year-old British teenagers that was measured by Raven's progressive matrices dropped by 2 points since 1980. Among the upper half of the scale, the results were much more staggering: the IQ dropped by 6 points from where it was in 1980.

The article explains that the teenagers' culture has probably dumbed down. Flynn himself believes that the upper class that dominates the upper portion of the IQ scale has been contaminated by the lower, "rebellious" peer culture of the lower classes.

Sunday, February 08, 2009 ... Deutsch/Español/Related posts from blogosphere

Reasons why climate policy will collapse

Roger Pielke Jr wrote an interesting article about the actual reasons why climate policy is going to collapse.

An unnamed Dutch kid from a book about Hans Brinker (Dr Pielke, your description is incorrect!) plugs a hole in a dike with his finger, resembling the recent activity of climate activists and scientists.

He says that the dynamics of the climate discussion is not determined by the progress and changes in climate science, by a decade without any statistically significant warming, or by a cool winter. All these things are slow and irrelevant.

When the climate hysteria bandwagon crashes, many skeptics will think or suggest that it will have been a result of their work.

But the reasons will be different, Pielke argues. The main reason will be that the promises about the climate will be moved from the realm of dreams to the world of reality where they inevitably have to collide with facts.

And let me tell you, I agree with that. I would be much happier in a world where new scientific results - or their successful explanation to the broader public - would significantly influence political decisions but we're not living in such a nice world.

Climate science has always been an irrelevant puppet show, a young woman forced to be a prostitute by the side that was "winning" the ideological debate. Nothing substantial has changed about our scientific understanding of the climate for a decade or more.

What was driving the intense dynamics has always been politics, the personal interests of various groups, and groupthink that has run amok.

Friday, February 06, 2009 ... Deutsch/Español/Related posts from blogosphere

Answering a critic from a cartoon

Welcome, Abstruse Goose readers. If you click the colorful unicorn on the AG page, there is a touching story about the way how science makes unicorns extinct. I have similar feelings, too. Except that the real scientific theories are my unicorns: they're so cute.

And I am worried about the coming world of an anti-scientific propaganda that makes theories and science unnecessary for most people who seem to prefer sociological arguments and conspiracy theories. So my reply to the unicorn cartoon is fuck critics of string theory even though, let's admit, most of them are already fucked-up.

Click the picture to zoom in.

A couple of physics blogs, including, have recently posted the cartoon above. A boy is saying some very stupid things that he considers to be arguments against the validity of string theory. On the other hand, a girl who seems to be familiar with string theory reacts in the only way that actually makes any sense in this context.

A hot commercial break: See an animated GIF of the most popular Calabi-Yau manifold (click!) among most string theorists, the quintic hypersurface
The deeply flawed and brutally misinterpreted propositions made by the boy have recently been repeated by thousands of laymen as a new mantra. There are whole websites on the Internet that have been alive for years just by repeating the stupid boy's statements from the cartoon: a classic infinite loop of obsession. I can understand why people want to repeatedly watch porn: we are hard-wired for certain things.

But the people who can read these websites more than thrice - or more than for one week - must suffer from some kind of severe mental deviation or retardation, an insatiable thirst for repetitiveness that I simply cannot comprehend. They must believe that if they eat the same excrement from a cartoon 1,589 times (guess where the number comes from), it becomes a yummy pizza. ;-)

Thursday, February 05, 2009 ... Deutsch/Español/Related posts from blogosphere

Clean coal: Obama vs Gore

Off-topic: If you're into IT, databases, or SOA and this stuff, you should surely check the blog of Mr Roman Staněk, a Gentlemen who has created huge and successful IT companies and who still has a lot to tell you not only about the technical and business issues!

Bloomberg analyzes the Obama-Gore split about coal. Gore's organization is spending hundreds of millions of dollars for clean-coal trash-talking while Obama defines clean coal as one of his big goals that should get billions of dollars from his budgets.

As a former kid in the most industrialized socialist country, I know quite a lot about dirty coal. We were surely not breathing and talking about carbon dioxide which is a clean, friendly gas. The plants were emitting megatons of sulphur oxides, nitrous oxides, carbon monoxide, aerosols, uranium, and everything else you remember from your chemistry (and nuclear physics) classes. ;-) The Czech brown coal is very rich, indeed.

In the 1980s, plastic materials that could be burned into pure H2O and CO2 were classified as completely clean. And it was very sensible. People were dreaming that something similar could have been done with coal - and with some modern filters, it has almost become the reality in the last two decades.

Well, if some people want to treat CO2 as a pollutant, that completely changes the equation. At this moment, the technologies to sequester or otherwise suppress the CO2 are not viable. Whether or not research will make them viable in the medium term is a speculative question. No one can know for sure.

The real political question is of course not concerned with these prophesies. The real political question is what the U.S. and other countries are going to do with coal before the hypothetical research miracle comes true. ;-) And it's pretty clear that Gore and similar luddites would love to ban it while Obama is likely to support it and describe the old-fashioned coal as a material that is going to become clean in the future.

Because of Obama's key role in the administration, crazy people who also care about their careers - such as Steven Chu - are beginning to rationalize their opinions about coal. In 2007, Steven Chu described coal as "his worst nightmare". In January 2009, it became a "great natural resource". :-)

Things may become interesting - and hopefully different than Gore would like them to be.

Gavin Schmidt is his own mystery woman

Alarmism: plagiarism, lies, intimidation

Gavin Schmidt, a blogger with RealClimate.ORG and an ideologue paid by NASA, has written quite a few crazy things to defend the indefensible.

For example, when a paper claimed that phytoplankton destroys a lot of ozone, Gavin Schmidt argued that it didn't matter. He proudly revealed that his favorite climate models neglected all of ozone (a top-five greenhouse gas) and probably most of the dynamics of the oceans (with their huge heat capacity).

I said simply Wow. Get back to the graduate school, Gavin.

This story occurred more than half a year ago and the times are different these days. Over at Roger Pielke Sr's blog, Henk Tennekes, an expert in these matters, analyzes Schmidt's stunning ignorance about the effects that are important for the weather and for the climate (yes, oceans are important for the climate: a few-meter-thick layer of the world ocean beats the heat capacity of the whole atmosphere) and recommends Mr Schmidt to return to the graduate school.

Antarctica and a mystery woman

But there's another story that is more sociologically revealing. On Sunday afternoon U.S. time, Steve McIntyre of ClimateAudit.ORG identified a likely reason behind a small part of the warming that was recently claimed to have occurred in West Antarctica. A weather station, Harry AWS, was relocated and its temperature readings showed some discontinuity.
Bill Gray's paper: On the hijacking of the American Meteorological Society (Word), via Tom Nelson
On RealClimate.ORG, there has been an article about the Antarctic temperatures, Warm reception to Antarctic warming story, published on January 27th. As you can imagine, when Steve wrote about his findings, his readers instantly contributed comments about Steve's findings to the RealClimate.ORG discussion thread, too.

Wednesday, February 04, 2009 ... Deutsch/Español/Related posts from blogosphere

One ton of a snake

Mirror (U.K.), a blog: a snake whose weight is 2500 pounds was found in the South American rainforest. It lived 60 million years ago and it's so big because it was very happy because the local temperatures were between 30 and 34 °C, five degrees above the present values.

Via Marc Morano.

RSS MSU released their January 2009 temperatures. The global anomaly was 0.322 °C, i.e. 0.15 °C warmer than the December 2008 anomaly and the warmest reading since August 2007. In the mid troposphere, the reading went from negative numbers to +0.105, the warmest figure since October 2007.

Off-topic but fun: A Greek Rube Goldberg domino machine. ;-) And fast opera singers will surely appreciate The Mom Song.

Relativistic phobia

A moderately technical posting about the flaws of Bohmian mechanics was followed by a sociological text about anti-quantum zeal. So it is natural to complete the commutative diagram and supplement the text about the Lorentz symmetry and computational universes by a sociological essay about the relativistic phobia. Here it is.

The 20th century revolutions

The quantum revolution has had a more profound conceptual impact on our understanding of the real world than relativity. We were forced to abandon determinism and the very idea that objects had well-defined, unique properties before they were observed. Evolution has trained us to understand a classical limit of the real world only because it was sufficient to hunt the deers and to eat bananas, besides other pleasures of life.

So it is not too surprising that many people still have serious psychological problems with the postulates of quantum mechanics, even though they have been known to be correct for more than 80 years.

Special relativity has been around for more than 100 years. It doesn't challenge our most basic assumptions about "reality" of things. Puppets have created movies that explain these crisp and clear ideas to children in the kindergartens - like the video above. But this science is still sufficiently difficult for most people - including most physics fans - which is why most of them are still hoping that special relativity will go away. As we will see, their hope is based on a complete denial of all relevant experimental input as well as a misinterpretation of all newer theories, beginning with general relativity.

Tuesday, February 03, 2009 ... Deutsch/Español/Related posts from blogosphere

Claud Lovelace: membranes in 28 dimensions

Off-topic but cool: Google Earth 5.0 has been released. It includes a time machine (historical pictures of places), detailed images and data from beneath the ocean, 3D pictures of Mars, and tools to create presentations (including a microphone), among other things.

Download Google Earth 5.0. See Dmitry's blog or CNN or YouTube for some demo videos. The program even allows you to vomit because it was apparently created by Al Gore, much like the Internet. Also, download Skype 4.0.

Claud Lovelace was the first Gentleman who encountered the critical dimension, D=26, in string theory more than 35 years ago. As you know, the supersymmetric string critical dimension is D=10.

Membranes with one temporal dimension, d=2+1, lead to D=10+1 and it could perhaps be natural to think about a bosonic M-theory in D=26+1 dimensions. Also, one may imagine worldvolume theories with two times, i.e. d=2+2, in D=10+2 or D=26+2 dimensions. Note that in all these cases, you are left with 8 (super case) or 24 (bosonic case) transverse dimensions.

Is this story going beyond this simple numerology? Most string theorists would answer Probably not. However, a few brave souls including Lovelace have been trying to construct a new mathematical formalism with symmetries and ghosts that would be as powerful as conformal field theory of 2D string worldsheets - but it would be different, higher-dimensional, and perhaps more fundamental.

The Financial Permeability

Episode 2x14 of The Big Bang Theory:

Sheldon begins to develop a method to help with Penny's financial problems. At the end, Leonard has to face Kurt, Penny's mountain ex-boyfriend. Leonard's own project works out but the heroes don't always get the credit they deserve while bastards often get much more credit than they deserve.

Monday, February 02, 2009 ... Deutsch/Español/Related posts from blogosphere

Pilsen: City of life

Pilsen is a candidate for the European Capital of Culture 2015. It's kind of fun to see what videos and materials the local officials are submitting to the contest.

The video above is modest and doesn't try to paint the city more impressive than it is. But it's pretty pleasant, anyway. And for a patriot, it's an interesting feeling to be familiar with pretty much every place and every sort of event.

Hansen's colossal failures: Super El Niño predictions

Roger Pielke Jr mentions James Hansen's 2006 predictions about a "super El Niño" that would rival the 1983 and 1997-1998 El Niño events.

In March 2006, Hansen wrote a paper claiming the following:

We suggest that an El Niño is likely to originate in 2006 and that there is a good chance it will be a “super El Niño”, rivaling the 1983 and 1997-1998 El Niños, which were successively labeled the “El Niño of the century” as they were of unprecedented strength in the previous 100 years.
To check whether his prediction worked, you should open
ENSO cycle status and predictions (PDF).
On page 20 or so, you will see that the primary index describing El Niño and La Niña episodes is the ONI index, the 3-month running average of the Niño 3.4 regional temperature anomaly in °C (the latter is also discussed on page 5). If this index jumps above 0.5 for five consecutive overlapping 3-months periods, we talk about an El Niño episode. The same circumstances with the opposite sign defines a La Niña episode. These longer events are less frequent than simple "La Niña conditions".

Incidentally, you should also look at today's sea surface temperatures. The uncertain seed of a potential El Niño seems to have disappeared and we are back to pretty much clean La Niña conditions although it is not a terribly strong La Niña.

Now, if you return to the PDF document above, you may also check page 23 that enumerates El Niño and La Niña episodes since 1949.

Sunday, February 01, 2009 ... Deutsch/Español/Related posts from blogosphere

Calabi-Yau manifold: animated quintic hypersurface

Click to zoom in.

The animated GIF shows a real two-dimensional visualization of a three-dimensional section of the quintic hypersurface in CP^4, the most popular smooth Calabi-Yau manifold among most string theorists.

Go to Jeff Bryant's page for more words about it and a Mathematica notebook.

Computational universe vs Lorentz symmetry

Moshe Rozali wrote a very sane text about the importance of Lorentz symmetry for the search for the fundamental laws of Nature:

The Universe is probably not a quantum computer
I agree with every word he wrote. He says that many people who are following the physics blogosphere want to believe that their area of expertise is actually sufficient to find a theory of everything.

So Seth Lloyd of the quantum computing fame wants to believe that the world is a quantum computer. Robert Laughlin wants to imagine that quantum gravity is an example of the fractional quantum Hall effect. Other people have their own areas of expertise, too. Peter Woit wants to believe that a theory of everything can be found by mudslinging and defamations while Lee Smolin wants to believe that the same theory can be found by selling caricatures of octopi to the media (following some subtle and not so subtle defamations, too).

Moshe Rozali correctly tells them that if they are going to ignore the Lorentz symmetry, a basic rule underlying special relativity, they are almost guaranteed to fail. Lorentz symmetry is experimentally established and even if it didn't hold quite accurately, it holds so precisely that a good theory must surely explain why it seems to work so extremely well in the real world.

Moreover, the state-of-the-art theories of the world are so constrained - i.e. so predictive - exactly because they are required to satisfy the Lorentz symmetry. Because of this symmetry, quantum field theories only admit a few marginal or relevant deformations. If you assume that they make sense up to extremely high energy scales, you may accurately predict all of their low-energy physics as long as you know a few important parameters. Such a "complete knowledge" of physics in terms of a few parameters would be impossible in non-relativistic theories.

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