Sunday, February 27, 2005 ... Deutsch/Español/Related posts from blogosphere

Wick rotation

In the discussion under the article The entropic principle about the recent paper by Ooguri, Vafa, and Verlinde, there has been a significant opposition of many participants against the concept of the Wick rotation - one invented by a renowned and virtually unknown physicist Gian-Carlo Wick. They were saying that this mathematical method can't be trusted; they were comparing the use of the Wick rotation to the idea that physical theories should not be tested experimentally. Because I believe that most of this criticism is unfair and the Wick rotation is a useful, and in many cases essential mathematical tool to calculate the physical predictions of a quantum theory, let me dedicate a special article to this issue. Peter Woit added his comments about the Wick rotation, too.

First of all, a summary

The Wick rotation is a calculational trick in quantum theory in which we assume that the energy or the time are pure imaginary. We do the calculations given these assumptions, which are often more well-defined, and then analytically continue the results back the usual real values of time and/or energy. It works. But let's now look at the situation a little bit more closely.

Behavior of path integrals

According to Feynman's approach to quantum mechanics, the probability amplitudes may be calculated as the sum (well, a path integral) over all conceivable classical histories of the physical system. Each of them is weighted by

  • exp (i.S/hbar)

where "S" is the classical action calculated for this history. As you can see, the absolute value of this weight is always equal to one as long as "S" is real. From a naive viewpoint, that does not seem to be a good starting point for a convergent integral; the integral keeps on oscillating. Convergence is improved if we add a small negative real part to the exponent. Write the action as

  • S = int dt L

and imagine that "dt" has a small imaginary part. You obtain the weight

  • exp (i.(int dt (1+i.epsilon)).L/hbar).

Because of the term proportional to "-epsilon" in the exponent (i.e. because of the factor "exp(-epsilon.S)", roughly speaking, the contribution of the configurations with a large action will be exponentially damped, and the convergence will improve. This regularization is applied both to ordinary quantum mechanics as well as quantum field theory. In the latter case, it's the origin of the "i.epsilon" prescriptions for the propagators etc. While the naive Feynman's prescription is obviously reproduced for "epsilon" going to zero, a tiny nonzero value of "epsilon" is essential for making the path integral convergent.

The Wick rotation

This was not the Wick rotation yet, but I hope that the inevitability of this "epsilon" treatment is obvious to everyone: the simple prescription of Feynman is a heuristic inspiration, and the oscillating path integral must be regulated in some innocent way. The "i.epsilon" prescription is the way that preserves all symmetries. Not a big deal. Now let's look at the real Wick rotation.

Up and Down: Czech Oscar candidate

The Czech director Mr. Jan Hřebejk has produced a new movie in 2004, namely Horem pádem which is translated as Up and Down (quite a boring translation). It's a rather frustrating comedy about the contemporary Czech society. When we describe it as a comedy, be sure that only black humor is being served. You may also look at the review in the New York Times. A random generator has decided that this movie would be shown as the #1 among all 49 nominated movies.

There are two main storylines in the movie available as a DVD above that eventually join seamlessly:

Franta (Jiří Macháček) and his wife Míla (Nataša Burger) who is psychologically unstable and dreams about a kid are not allowed to adopt a child because Franta is a former soccer hooligan. This couple lives in a crowded apartment in Prague and they eventually buy a child that two smugglers found in their truck. Franta's friend who is a skinhead does not like the child's dark skin. The movie describes the life of racists and various anti-immigration feelings in a realistic fashion.

Saturday, February 26, 2005 ... Deutsch/Español/Related posts from blogosphere

Sultans of string

Arun has pointed out an interesting article about the string theorists at the Tata Institute in India:

The article says a lot of interesting things about the interaction between the Indian culture and theoretical physics, and about many heroes of string theory from India and friends of ours.

Indian string theory has the best outcome per dollar in the world ;-) which is one of the arguments by Andy Strominger that have - during a dinner in the Society of Fellows that I attended - convinced Lawrence Summers, the famous president of Harvard University, to find some extra funding for our Indian colleagues.

Lawrence Summers asked how much money could improve their life by a significant amount, and Andy Strominger answered $100,000.

Friday, February 25, 2005 ... Deutsch/Español/Related posts from blogosphere

New record prime

The Mersenne numbers are the numbers of the form "2^p - 1". Several centuries ago, some people used to think that these numbers were always primes if "p" itself is a prime. While it's true for the first few values, the general claim is, of course, false. Primality of "p" is a necessary condition for primality of "2^p - 1", but not a sufficient one. (It's necessary because if "p=qr", then "2^q - 1" and "2^r - 1" are divisors of "2^p - 1".)

In fact, only 41 Mersenne primes are officially known. The highest one, "2^24,036,583 - 1", is also the greatest officially known prime integer in the world. It was found in May 2004. Usually, the exponent roughly doubles if you want to find a new Mersenne prime. However, the Mersenne prime numbers look surprisingly dense for the exponents between 20 million and 26 million.

An international network of computers GIMPS whose website is at

is looking for new Mersenne primes. You may join. One can see that the main page of this server announces that a new record prime may have been found. It would be the 42nd known Mersenne prime number. I predict that the exponent "p" will be

  • "p = 25,964,951"

Note that if you find the first Mersenne prime with at least 10 million digits, you will win at least 1/2 of the $100k award from the EFF foundation. It takes roughly one month for a 3GHz computer to test (using the Lucas-Lehmer test) a number like "2^34,362,227 - 1" which is how a candidate for a 10-million-digit prime number looks like.

Thursday, February 24, 2005 ... Deutsch/Español/Related posts from blogosphere

The entropic principle

The anthropic principle has a new competitor.

It's called the "entropic principle" even though Hirosi Ooguri, Cumrun Vafa, and Erik Verlinde finally did not use this entertaining term for the title. Let me first state a popular version of the principle for those who don't expect to follow the details of this article:
  • The probability that the cosmological evolution will end up as a Universe with a particular shape of the hidden dimensions (and particular values of the fluxes) is determined by the (exponentiated) entropy of a corresponding black hole whose geometry flows via the attractor mechanism to the given shape of the Universe near the horizon. Note that this contrasts sharply with the "anthropic principle" - which itself is not a principle, rather a lack of principles. In the anthropic principle, the corresponding probabilistic weight is determined by the ability of the Universe to support intelligent life.
Topological string theory allows one to calculate the partition function which is a function of the complex structure moduli of a Calabi-Yau three-fold. Except that it's not quite a function; because of things such as the holomorphic anomaly, it is a "wave function". What do I mean? You may think that it is a function that only depends on the holomorphic moduli. Naively, you would expect that the function is holomorphic - it depends on X but not Xbar.

However, an infinitesimal change of the reference point in the moduli space induces the so-called holomorphic anomaly which a slight, exactly understood dependence on Xbar that can be locally visualized as an infinitesimal Fourier transform. By an infinitesimal Fourier transform, I mean the conversion of a wave function "psi(x)" to "psi'(x')" where "x' = x+epsilon.p" - you see that we are mixing "x,p," the coordinates on the phase space. Therefore it is more appropriate to talk about the partition sum as a vector in a Hilbert space rather than a well-defined function.

Bush in Slovakia

The most powerful man in the world is just visiting my broader homeland - and it's a good opportunity to promote Slovakia.

Slovakia used to be a part of Czechoslovakia between 1918 and 1992. Czechoslovakia is the country in the middle of Europe; you should not confuse Slovakia with Slovenia which is a country in the former Yugoslavia and because "Yugo" means "Southern", you may guess that Slovenia is more to the South. You may think that I am assuming that the readers are idiots. However, USA Today published an article that claimed that the Bratislava Castle is located near the beaches of the Adriatic sea. :-)

Not only USA Today are ignorant about the Central European geography. On the pages of the White House you may find a photograph of Bush talking to the Czech president Klaus. The caption says that Bush is chatting with the Slovak president Ivan Gašparovič. :-) Sorry, I've already sent a mail to George and he has fixed the error on the web page.

Wednesday, February 23, 2005 ... Deutsch/Español/Related posts from blogosphere

The whole Ginsparg on your hard disk

Paul Ginsparg, the founder of, used to be one of the staunchest warriors against the robots. One of Paul's secret weapons was the automated "seek-and-destroy" procedure against your site that many stupid robots and visitors of my blog carelessly clicked at. Please don't click at this sentence otherwise your domain will be disconnected from the arXiv's!

He believed that the internet was entering a new era - an era of websites such as that contain a huge amount of stuff and can't be mirrored. Consequently, he disliked the search engines because they were attempting to mirror the whole archive of Ginsparg which was clearly impossible: it would take an infinite amount of affine time. However, a search engine called

suddenly showed that it was not only possible, but in fact very easy to reproduce the whole archive. Later, Google has also introduced a version of an interdisciplinary SPIRES with a full-text search capabilities

While Google was the first company to defeat Ginsparg's no-go theorem, the second defeat has been even more spectacular. She's called

(guess who took the picture on the website above) and she's, together with Alanis Morissette and a few more friends, a Canadian girl who rocked the world. What is her answer to

It sounds great, does not it? How many of you have been sitting in the aircraft with your laptop, before you suddenly got a great idea, but you needed a formula that you knew could only be found in hep-th/0301173 - but where can you get this paper 6 miles above the middle of the Atlantic?

An amicable faculty meeting

The Harvard's FAS (Faculty of Arts and Sciences) faculty meeting today - a continuation of the meeting from last Tuesday - may be characterized as a mostly civil exchange of opinions between president Lawrence Summers and the faculty. In other words, the last meeting (that took place between 4 PM and 6 PM) was on the edge of becoming just another boring faculty meeting. Among the 30 speakers or so, there has been essentially one speaker only who called for Summers's resignation. It was our condensed matter colleague DF. The only point of his talk that most participants understood was the bitterness, and DF had to witness possibly the most diluted applause in the history of the FAS faculty meetings.

Another speaker, a woman at the very end of the session, discussed the issue of innate differences - something that many people incorrectly expected to be the main focus of the discussions. The risk that Summers could be pressured to resign because of the opinion at the FAS has mostly disappeared.

Except for the two talks I mentioned, most other talks were dedicated to the questions about Summers's powerful leadership, its advantages, its disadvantages, the balance between the style and the factual content (a music professor at the very beginning asserted that everything was about the style, much like in music - an opinion that most participants did not share), the amount of mutual trust between the president and the faculty, and the separation of power between the president and his fellow professors.

Many of the speeches have been pretty nice pieces of literature - well, let me admit that Summers's speech at the beginning would probably remain #1 in my list - and many speakers recalled kind of entertaining stories about the first moments when they joined Harvard University decades ago. For example, one professor remembered that he joined Harvard in 1978 when the Red Sox used to be losers and the faculty meetings used to be boring. Another speaker (or perhaps the same one?) asked whether we wanted a president who was unmemorable or Mr. Platitude - the kind of people who are found in abundance among the university leaders. ;-)

Other speakers were comparing Summers and this whole story to various episodes from the history textbooks, or they were comparing the aptitudes required from a CEO vs. a university president. Nevertheless, most of the physicists who attended the meeting - including Nima, Lisa, and others - think that the concentration of the non-trivial content in the speeches was rather low. Nima argues that these faculty meetings should be run by scientists in order to increase their efficiency - which may sound as a good idea except for the fact that the physics faculty meetings are usually incredibly boring. ;-)

Although there have been roughly two more radical speeches only (and maybe one is a better word), one can still say in most of the cases whether the speakers supported the president or not - and the ratio was about 50:50, I would say. This ratio - one that reflects the opinions at Harvard according to a poll organized by The Crimson - is no accident. Dean Kirby, who was leading the discussion, has composed the initial list of speakers in such a way that it was balanced.

One of the speakers has been known to the participants of the last week's faculty meeting - Mrs. Theda Skočpol (which means "Jumpfield" in Czech, and it is a shortened version of one of the funniest Czech surnames "Skočdopole" - "JumpToTheField"). Although she has already been elected (the word "elected" is probably not the right one) to one of the new pro-women committees, she retained her critical attitude toward President Summers. I did not learn much from her talk, and I remain skeptical about such "ad hoc" committees.

After 5 PM, someone proposed another committee that would mediate communication between president Summers and the faculty - including Profs. Knowless, Skočpol, and Verba. This proposal has almost been approved, but because Philip J. Fisher from the English department suddenly complained that such a result of the meeting seemed pre-determined and henceforth undemocratic (and the speaker also complained that there was one scientist, two social scientists, and no representatives of the humanities in the committee), the proposal was eventually cancelled by its proponent himself. I personally have no idea how would we use such a committee to comunicate with the president.

David Laibson, professor of economics, originally planned to read the text of the letter he composed with Claudia Goldin - a letter that was endorsed by 186 full professors at Harvard - but the atmosphere was already so peaceful that David Laibson said a couple of rather neutral statements that I've already forgotten.

The meeting was held in the Lowell Lecture Hall and it was attended by 400-500 professors. Note that the capacity of the lecture hall is just 352 people, and therefore many of us had to stand most of the time. The usual attendance at the faculty meeting is about 100 people. The lecture hall was surrounded by journalists with hundreds of microphones and cameras and they were trying to provoke the participants and get some sharp statements from them.

Before the meeting, a group of radical students was screaming slogans such as "We vote NO!", "Summers: racist sexist anti-gay" and they were drumming. I appreciate their happiness and fresh, independent, and original ideas and emotions - but this respect can't stop me from encouraging their parents to spank these young colleagues of ours a little bit more often. Every five-year old kid knows that it's wrong to scream that the president is either a gay or anti-gay (the difference being a matter of convention by the CPT theorem). ;-) As soon as I replied to these kids "We vote YES!", roughly 10 camcorders started to shoot me. At that moment I decided to turn as silent as possible; on the other hand, Cumrun Vafa has made an interview after the faculty meeting.

Some professors have included the confidence vote for the next, March 15th faculty meeting. And yes, I am confident that it is more accurate to call it a "confidence vote" rather than "no-confidence vote".

Monday, February 21, 2005 ... Deutsch/Español/Related posts from blogosphere

The horrible CERN girls (LHC)

Did you know what the LHC stands for?

which means "the horrible girls from CERN". This high-energy rock band

is famous because these girls appear on the first image on the web. The music (and lyrics) is pretty cool, too! For example, try Liquid Nitrogen. Thanks to Patrick Veverka ("Veverka" means "squirrel" in Czech) for this information.

Sunday, February 20, 2005 ... Deutsch/Español/Related posts from blogosphere

Students for Larry

Update: the previous text about the Summers controversy now contains

What do the Harvard students think about the recent controversy? The only website that answers this question is

Meanwhile, the petition by Profs. Claudia Goldin and David Laibson

has collected more than 160 signatures of the full professors who support the president. While president Summers enjoys the support of a majority of the scientists, it's less clear in the humanities and soft sciences.

To be balanced, let me tell you that the negative people have also organized a petition that even wants to declare no-confidence. It's not obvious whether it has already been endorsed by some scholars. But the newspaper articles show that some people are very bitter, and therefore I expect that even this petition against Summers will find some support.

A group of negative students plans to organize an anti-Summers demonstration on Tuesday before the FAS faculty meeting at 4 p.m.

Thursday, February 17, 2005 ... Deutsch/Español/Related posts from blogosphere

Mark Jackson & cosmic strings

Mark Jackson just gave us a very nice talk about cosmic strings. He used his Apple laptop with a PowerPoint presentation. The talk explained most of the issues about the types of cosmic strings and cosmic superstrings; their stability; the bounds for their density and tension; the probability of intercommuting pairs of F-strings, D-strings, (p,q)-strings, and all combinations of these objects; the gravitational waves emitted from the cusps and their detection by LIGO and LISA; and finally the candidates for cosmic strings, namely CSL-1A/CSL-1B and the 417-days-delayed double image.

The previous blog text about the cosmic strings was here.

The talk was not only a very nice review of all the stuff that we've discussed previously, but it also presented a shocking surprise: Mark has identified the coordinates of CSL-1 - the Cosmic String Lensing candidate. So far the coordinates have been largely secret.

Imagine that you're in charge of a telescope that is comparable to the Hubble telescope, or you have just launched your personal space shuttle which carries a probe, telescope, or something like that - and you want to see whether there is a discontinuity near the object CSL-1.

How do you find the coordinates?

You open the PDF version of the paper by Alcala et al.

and you search for "double early type". As a consistency check, the redshift should be z=0.463. Try to contact all your astro-friends and give them these coordinates of CSL-1. Well, to simplify your work, the coordinates are:
    • right ascension: 12 hours, 23 minutes 30.6 seconds (note that this angle is measured in hours, 1 hour = 15 degrees)
    • declination: -12 degrees 38 minutes 57 seconds (southern celestial hemisphere, close to the equator)
    • double early type, z=0.463, S/N 12
Moreover, I've made another fun observation. The object listed just above this CSL-1 candidate is described as an "edge on disk" - well, this could be exactly the discontinuity by which the cosmic string cuts a disk in halves. Its coordinates are
    • 12h 23min 29.7sec, -12 deg 38' 27'', z=0.223 (?)

Unifying the Harvard community

Update: if you're a professor at Harvard, you should consider to sign a letter by Claudia Goldin and David Laibson whose content is similar to the second part of this article - the PDF file with the letter is at

Not only because Harvard and Princeton are usually the top two ranked universities, many people are obviously interested in the developments surrounding the world's most famous university president, namely Lawrence Summers.

On Tuesday, professors Grosz, Hammonds, Skocpol, and maybe others have asked Lawrence Summers to publish the full text of his remarks at the conference in January to "clean the air". Although it initially looked as a bad idea to many of us, president Summers has now released
and informed his colleagues about these issues; he has also issued new apologies. As far as I see right now, these speeches are even more brilliant than I previously thought. And the air is almost certainly clear right now. You can see that many statements have been exaggerated. It's my private opinion, but I believe that restricting Summers's freedom of speech - and his bright ideas - is a highly counterproductive suggestion.

Physics seminar videos

How many videos from physical seminars do you think are available on-line? The answer is "many". See the page created by Serkan Cabi

If you think that this is an impressive list, you could also try to visit Cabi's glasses i.e. his blog at MIT:

where physics - and even string theory - plays an important role.

Wednesday, February 16, 2005 ... Deutsch/Español/Related posts from blogosphere

Kyoto takes effect (update)

This article has been corrected.

The Kyoto protocol comes of age. Finally. How much will it - and its hypothetical future extensions - cost? Let's talk about the catastrophic scenario in which people won't abandon this weird international treaty and they will really try to stabilize the CO2 concentrations in the atmosphere.

Reuters published estimates that it would cost 18 quadrillions (18 times 10 to the 15th power):

If you don't know what a quadrillion (U.S.) means, it is roughly speaking an infinite number, and you may object to such an unrealistic result and label the news from Reuters as a kind of typo. What about the estimates from the real people behind the Kyoto protocol?

Tuesday, February 15, 2005 ... Deutsch/Español/Related posts from blogosphere

Kenneth Lane on SSC and LHC

Kenneth Lane from Boston University just gave an interesting talk about a topic that you can view as messy and boring: the imperfections of hadron colliders. He described various types of background:

  • real background
  • faked background
  • detector-induced background
There are a lot of effects caused by boring, well-known physics that can fake a signal for new physics. You have to reduce these fakes to at least the level of the real signal - if there's lots of real signal - or far below it if the real signal is rare (i.e., produces only a few events).

He showed the structure of the detectors - such as the huge detector GEM - designed for the Superconducting SuperCollider (SSC) that has been stopped 10+ years ago. That was sad. We could have had a lot of data already. One of the clear lessons from the SSC is that the particle physicists should have voted for the Republicans at that time :-) - although the current correlation between the parties and the physics policies is less clear and might be, in fact, reverted.

Monday, February 14, 2005 ... Deutsch/Español/Related posts from blogosphere

Frank Wilczek about Penrose's new book

Frank Wilczek did not allow his first Nobel prize to reduce his activity, and one of the many things he recently did was to read the new book The Road to Reality by Roger Penrose, even though it has about 1100 pages. Wilczek wrote an excellent review of this book for a recent issue of Science. Unfortunately, you need a subscription to access the article, or you need to buy the paper version.

Although I have not read the whole book, it does not seem necessary to determine that I completely agree with 's comments. First of all, is a highly original thinker. Among his discoveries, we find

  • Various methods and solutions of GR related to dynamics of black holes (which includes his method to gain energy from the Kerr black hole)
  • The Penrose (BMN) limit of geometries, a kind of pp-waves
  • The Penrose causal diagrams
  • The esoteric Insect formalism for GR: tensors are bugs and indices are their legs
  • The Penrose tilings and quasicrystals
  • The twistors (1967)
  • Spin networks that he invented decades before they became fashionable in loop quantum gravity which was another framework that people were proposing as an approach to quantum gravity
If I paraphrase him, Wilczek argues that Penrose's book should rather be called Fifty Sidewalks Around Reality. It is a physics-oriented book, but otherwise another eclectic interdisciplinary work with many layers, different ideas, and viewpoints. Wilczek looks at the book from three different perspectives. Penrose is most successful from the viewpoint of a teenager who is interested in math and physics: the book will make such readers excited about the complex numbers, relativity, and spinors. (Although it is unlikely that they will learn what a line bundle on the twistor space is.)

Libertarian girl was a hoax

The frequent visitors of my blog have probably noticed that one of the "social" links points to the blog of Libertarian Girl:

She started with and then she moved her blog to I've been one of the naive people who believed that she was real, and I am proud about it. Click at these links to see what happened with that picture!

In fact, in my opinion, there exists no physical law that would strictly prohibit the existence of a young gorgeous girl who spends hours with her libertarian blog. Many girls and women are very close to that point! Libertarian girl always looked not only intelligent, but a little bit too tough - for example she was pretty strongly pro-war (even pro-war in Iran). But all these things are possible, aren't they?

What about the girl on the picture? Her name is Viktoriya and she is a Ukrainian woman from Kiev "seeking man". This was probably enough for the inventor of Libertarian Girl not to be afraid of copyright infringements. After long speculations about her gender - which Libertarian Girl identified as sexism - someone has finally found the other picture: see the blog here.

Sunday, February 13, 2005 ... Deutsch/Español/Related posts from blogosphere

Shiites win

In agreement with my predictions and predictions of many other people, the large Shiite coalition has won the Iraq elections. They've received about 48 percent of the votes.

The second party is the Kurdish coalition. My favorite Iraqi List follows. The turnout was at 59 percent.

The large Shiite coalition, led by Ayatollah Al-Sistani, is mostly religious - although there are some liberals in it, too - and it will try to transform Iraq into a new kind of Iran. Let's hope that it will stay democratic for some time, and it won't become too dangerous for the world.

Saturday, February 12, 2005 ... Deutsch/Español/Related posts from blogosphere

EU constitution in space

In April, the Union will be sending its constitution, which will soon be approved by 100 percent of the working and celebrating people, into space.

A gold-bound copy of the Union's constitution has been delivered to the Soviet cosmic center Baikonur in Kazakhstan. A cosmonaut, namely comrade Tognini, is due to pass it to comrade Tognini (sic, see REDNOVA). Finally, Tognini will take it onboard of the Russian spaceship Soyuz (which means "Union" in Russian) as a symbol of

  • "how national interests can be transcended by channeling the aspirations of nearly half a billion citizens from diverse cultural backgrounds towards the common goals of peace, freedom and prosperity,"

using the words of the commissary for the peaceful expansion of the Union, comrade Verheugen. The Russian spaceship will bring the constitution to the International Space Station so that all the nations and the whole Universe sees that the Union is ahead of the American imperialists: America has never been able to transport its constitution into space, and until the heroes of socialism win their battle in the new world, there will be no progress in the so-called New World.

The bold decision to take the constitution into outer space is a revolutionary idea. Even the British Eurosceptic party UKIP said outer space was the best place for the constitution (BBC).

The spokesman for the European Soviet, comrade Kreuzhuber, said: "This time they asked to bring a copy of the European Constitution along." Although the constitution has yet to be ratified here on Earth, comrade Kreuzhuber points out that "this will make it one of the world's most thoroughly tested constitutions -- not just politically but physically." (REDNOVA)

The officials in the capital city of the Union have released a warning for its citizens saying that "if the Constitution is not approved through the referendums, it will drop on the Europeans' heads from space." (ZAMAN)

Figure 1: Comrade Chirac and French pioneers with flowers celebrate the constitution's journey through the Cosmos. Chirac is currently visiting Spain where less than 1 person in 10 will vote "no". The Spanish unemployment dropped to one-half and the Spaniards have received 219 billion USD from the Union since they joined in 1986.

Incidentally, the Union in the text above is not the Soviet Union but the European Union, and the news is not a joke. The previous blog article about the European constitution was here.

People in science and technology

My comments about the text by the three original authors follows the bullets.

A private response to a text by three respected people from Stanford, Princeton, and MIT

Harvard President Lawrence Summers' recent comments about possible causes of the underrepresentation of women in science and engineering have generated extensive debate and discussion—much of which has had the untoward effect of shifting the focus of the debate to history rather than to the future.

  • Interestingly enough, the reason why a meaningful discussion about a scientific topic is primarily based on the data from the past and not so much on data from the future is that we know the past, but we don't know the future - at least I don't know it. Maybe the authors of the text above know the future and they can therefore use it as the primary argument, in which case I apologize. ;-)
The question we must ask as a society is not "Can women excel in math, science and engineering?"—Marie Curie exploded that myth a century ago
  • ... fair enough ...
—but "How can we encourage more women with exceptional abilities to pursue careers in these fields?"
  • This is an important educational and political question, but president Summers wanted to modestly suggest that we should first ask whether we should expect a higher percentage of women to pursue careers in these fields. The answer is definitely not obvious, although it is treated as a self-evident dogma in the sentence above.
Extensive research on the abilities and representation of males and females in science and mathematics has identified the need to address important cultural and societal factors.
  • Other, more hard-science oriented research - and also president Summers in his speech and others - have also identified the need to address other important factors.
Speculation that "innate differences" may be a significant cause of underrepresentation by women in science and engineering may rejuvenate old myths and reinforce negative stereotypes and biases.
  • Lawrence Summers was much more polite - he did not explicitly identify the idea about "important negative stereotypes and biases" as an "old myth" although there exist reasons to use this language.
Why is this so important? Our nation faces increasing competition from abroad in technological innovation, the most powerful driver of our economy, while the academic performance of our school-age students in math and science lags behind many countries.
  • Sounds fine, except the fact that the causal relation between these politically attractive cliches and the question under consideration is not explained.
Against this backdrop, it is imperative that we tap the talent and perspectives of both the male and female halves of our population.
  • Good.
Until women can feel as much at home in math, science and engineering as men, our nation will be considerably less than the sum of its parts.
  • This assertion could very well imply that the nation will always be considerably less than the sum of its parts, although I don't exactly know what the second sentence means quantitatively. The sentence above is based on the assumption that the only natural situation is when different groups of people feel as much at home in all fields as other groups of people. What is missing is a piece of evidence supporting this statement - especially because there seems to be evidence that the assumption is not true. So I suppose that the opinion that everyone must feel equally at home everywhere is treated as another dogma that does not have to be justified - and the heretics who do not believe this dogma must probably be tortured.
If we do not draw on the entire talent pool that is capable of making a contribution to science, the enterprise will inevitably be underperforming its potential.
  • Well, definitely - if the words "talent pool" are defined scientifically, as opposed to a definition with a politically twisted meaning.
As the representation of women increases in every other profession in this country, if their representation in science and engineering does not change, these fields will look increasingly anachronistic, less attractive, and will be less strong.
  • Well, it does not seem terribly realistic to say that computer science and state-of-the-art electronics, for example, look "anachronistic" just because they happen to be pre-dominantly run by the males. Or are males themselves anachronistic?
  • The only sense how can I understand the statement about the field being "less attractive" is based on the visual feelings of the males. Obviously, their sentence seems to imply that they think that a field with a higher concentration of males is less attractive - which does not sound as a terribly balanced and fair comment about the genders. Some fields are attractive for someone but not attractive for someone else.
  • A field would become "less strong" if it did not use the talent pool, as discussed in the previous paragraphs. There can be various reasons why the talent pool is not used efficiently - and the political criteria that would eliminate some talented people and replace them by people who better fit some quotas would be one imaginable reason of reduced strength.
The nation cannot afford to lose ground in these areas, which not only fuel the economy but also play a key role in solving critical societal problems in human health and the environment.
  • It's hard to understand why "human health" and "the environment" were picked as examples of the "critical societal problems". First of all, they are just two examples of important problems for the society. Second of all, these particular societal problems are not associated with the fields in which women are most clearly underrepresented. Their percentage is lowest in fields like computer science, physics, mathematics, engineering - and neither of these fields seems to be primarily focused on human health and the environment.
Much has already been learned from research in the classroom and from recent experience on our campuses about how we can encourage top performance from our students. For example, recent research shows that different teaching methods can lead to comparable performance for males and females in high school mathematics.
  • Note that the authors themselves acknowledge that there are differences between the way how boys and girls typically learn mathematics. What the authors do not allow to be questioned is their assumption that the different ways of learning mathematics must always statistically lead to the same careers and outcomes.
One of the most important and effective actions we can take is to ensure that women have teachers who believe in them and strong, positive mentors, male and female, at every stage of their educational journey—both to affirm and to develop their talents.
  • I am happy to agree.
Low expectations of women can be as destructive as overt discrimination and may help to explain the disproportionate rate of attrition that occurs among female students as they proceed through the academic pipeline.
  • There are many factors that can be destructive. Equal expectations from two people who are not equal represent another important example - once again, the three authors only see one side of the coin.
Colleges and universities must develop a culture, as well as specific policies, that enable women with children to strike a sustainable balance between workplace and home.
  • It is definitely politically possible to impose new policies and offer the same benefits (and pay the same salary) to a person who does 1/2 of the work that another person does, and the remaining 1/2 of the time is dedicated to other activities. Another question is whether it is the right thing to do and whether the society will benefit from such policies. And it is not too hard to guess what the economists such as Claudia Goldin or Lawrence Summers think about this question.
Of course, achieving such a balance is a challenge in many highly demanding careers. As a society we must develop methods for assessing productivity and potential that take into account the long-term potential of an individual and encourage greater harmony between the cycle of work and the cycle of life—so that both women and men may better excel in the careers of their choice.

Although we have a very long way to travel in terms of recruiting, retaining and promoting women faculty in scientific and engineering fields, we can also point to significant progress. According to the National Science Foundation, almost no doctoral degrees in engineering were awarded to women in 1966 (0.3 percent), in contrast to 16.9 percent in 2001. And in the biological and agricultural sciences, the number of doctorates earned by women rose from 12 percent to 43.5 percent between 1966 and 2001.

  • Great. But I guess that until the percentage will be below 50 percent in a single field, there will exist some type of dissatisfaction. How many generations of fair treatment will be necessary before one will be "allowed" to argue that the theory of discrimination and discouragement as the only explanation can't fit the rich data that paint very different pictures in different fields?

Our three campuses, and many others, are home to growing numbers of women who have demonstrated not only extraordinary innate ability but the kinds of creativity, determination, perceptiveness and hard work that are prerequisites for success in science and engineering, as in many other fields.

  • The women at Harvard have demonstrated at least as much creativity, determination, perceptiveness, and hard work as the women at these other universities - and it is not quite clear why exactly the three campuses are mentioned and not Harvard even though this discussion was initiated by the president of Harvard University. The only explanation I have is that the three authors wanted to picture their campuses as the "nicer ones" although such a description can't be justified.
These figures demonstrate the expanding presence of women in disciplines that have not, historically, been friendly to them.
  • ... and to which many women were not friendly in the recent decades, judging by the numbers how many of them chose these fields.
It is a matter of vital concern, not only to the academy but also to society at large, that the future holds even greater opportunities for them.

... Oh, and finally, let me say that the text was written by the presidents of MIT, Stanford, and Princeton. Although there are three of them, I doubt that their text will become as stimulating and important as the speeches of the president of Harvard University.

Friday, February 11, 2005 ... Deutsch/Español/Related posts from blogosphere

Recent talks: Berkovits, Tegmark, Arkani-Hamed

Recently there have been several interesting talks at Harvard. Let me start with the postdoc journal club.

  • On Wednesday night, Nathan Berkovits was explaining his pure spinor formalism. He started with a description of the advantages and disadvantages of the RNS and Green-Schwarz formalisms. The superparticle is a good starting point for his pure spinor formalism and it already has many features that are also relevant for the superstring. For example, the polarizations of the gluon supermultiplet are described as a spinor-valued function A_alpha(X,theta) of the superspace - this has 16 x 65536 i.e. roughly a million of components to start with even for the open string. The situation for the closed string is this squared - i.e. more than one billion components. ;-) Nevertheless, the condition "lambda^a lambda^b D_a A_b(X,theta) = 0" is enough to kill all the degrees of freedom except for the 16 open (or 256 closed) physical modes. Here "lambda^a" is a pure spinor ghost - i.e. a spinor whose only non-vanishing bilinear is the middle-dimensional one, "lambda_a gamma_{jklmn}^{ab} lambda_b". Nathan explained that the pure spinors were already introduced by Cartan to describe possible complex structures in "2k" dimensions. The coset "SO(2k)/U(k)" is isomorphic to the space of projective pure spinors in "2k" dimensions. Nathan then discussed the BRST charge and its cohomology, and tried to answer many questions of ours about the relation of his BRST charge to the conformal symmetry - this relation is different from the RNS formalism because Nathan's BRST charges does not follow from a canonical gauge-fixing procedure. Finally, he wrote down a pure spinor Lagrangian for the "AdS5 x S5" background that - as he can prove - is a consistent conformal field theory. However, so far it has been difficult to extract useful information from this model.
Thursday is the usual day of the Duality Seminars - this semester they are dedicated to cosmology plus the interface between cosmology and string theory.

  • Yesterday, Max Tegmark from MIT gave an impressively high-tech Cosmological Duality Seminar about the cosmological parameters and their measurement. With his Apple, he was showing the Universe and stars at all possible distance scales. He has made a very good job in defending the idea that the funding for cosmology should grow, and that the whole NASA budget should not be sent to Mars. Max presented the animations showing how the CMB anisotropy as a function of the orbital momentum - as well as the visible matter density in the Universe at various scales and various other comparably important "graphs" describing the Universe - depend on various basic cosmological parameters: each of them seems to influence the patterns in a different way. It's impressive how cosmology is becoming a high-precision science. On the other hand, Max emphasized that we should not spend the rest of our lives with determining the parameters with higher accuracy. We should find relations between them - a goal mostly for the theorists.
Finally, Nima gave a captivating and provoking family lunch seminar today about some important grand questions and his approach to these questions:

  • He described his paper with Savas and Shamit about their friendly, predictive neighborhoods in the landscape. The type of toy models they consider are effective field theories with "N" real scalars. (Bobby Acharya et al. recently argued that the friendly neighborhood could appear in the M-theoretical landscape on G2 or Einstein seven-manifolds.) The potential in their toy model is a sum of quartic functions for each scalar field. This means that each scalar field increases the number of vacua by a factor of two - the total number of vacua is "2^N". Nima argues that assuming that the values of the parameters can be written as a constant plus corrections from all the scalar fields (which is another big assumption, I think), one can show that via the central limit theorem the average fluctuation of each observable will be of order "1/sqrt(N)". In the limit of infinitely many vacua, he says, we don't get a landscape where everything is undetermined. On the contrary, everything is determined with a relative error of order "1/sqrt(N)". One can get predictivity back, given certain assumptions! What are his new rules to deduce new physics? I've been trying to get a well-defined answer for quite some time, and I can only claim a partial success which can of course be caused by my being slower. Today, Nima formulated the rule pretty clearly:
    • A new particle or field or mechanism is only allowed to be added to our description of Nature if it is necessary for avoiding one of the "major" disasters - such as the destruction of the galaxies or atoms - disasters that one often discusses in the framework of the anthropic reasoning.
  • Obviously, one can raise the following objection:
    • Is not the new prescription for physics ruled out? The top quark, for example, seems unnecessary to avoid any of these low-energy disasters. This kind of anthropic thinking would have predicted that the top quark did not exist - and therefore Melissa Franklin et al. have falsified your paradigm 10 years ago.
  • What is the answer (of Nima) to this question?
    • We are not interested in these questions. We only want the neighborhood of the Standard Model. It's an assumption that we keep the broad features of the real world that are already known intact.
  • Well :-), it's OK not to be interested in these questions, but they seem necessary to define what the new principle constraining physics exactly is. Obviously, the principle must be refined to avoid the contradiction mentioned above. The refined version says something like:
    • Proposals for new physics that goes beyond the insights known in 2005, which is treated as an exceptional moment in the history of the Universe (and perhaps the humankind), must be justified by their necessity to avoid major global disasters such as the destruction of galaxies, nuclei, or atoms. Occam's razor must be applied - and the only way how a proposal for new physics can survive Occam's razor is an anthropic argument.
Well, when one formulates the new principle is this more accurate way, it seems slightly less convincing because of its special emphasis on the present knowledge. Why should we believe that a principle like that is a good guide to look for new physics if the same principle applied in earlier developments of physics is known to lead to incorrect conclusions?

Don't get me wrong. I like simple models and Occam's razor, and we always use simplicity as one of the rather important arguments. However, many things in our Universe are simply not minimal. In fact, according to Gell-Mann's totalitarian principle, everything that can occur in agreement with the symmetries will occur. This principle is usually used to allow all possible terms in the action involving given fields, but its moral generalization can also be used to allow for new fields and particles.

This observation implies that the requirements of simplicity are not a universal principle that can always be safely trusted when we try to pick the correct theory. They're often useful, but they're not universally valid. No doubt that Nima agrees. Nima et al. seem to suggest that exactly for "physics beyond the Standard Model", this principle of simplicity should suddenly become more important and more reliable than before. Also, beyond the Standard Model, the anthropic arguments should suddenly become more important - or even omnipotent. But I don't see a rational argument behind this approach. Simplicity, anthropic arguments, technical arguments, naturalness, and other arguments remain valid arguments, and giving them weights is a matter of intuition and personal psychology. I don't see why the Standard Model should be the critical line behind which we should suddenly change the way how physics is done and which arguments are important.

In this sense, I would probably guess that the resulting "minimal" models - and especially the new "anthropic sector" that is used to explain the cosmological constant and the Higgs mass - have comparable probability to be correct as any other models supported by some other, less anthropic principles - except for the obvious fact that the authors of the paper are big shots whose probability is always a bit higher. ;-)

Hockey stick has become a boomerang

Update: The M&M paper has appeared in Geophysical Research Letters. Newspapers explain that climate science is much like Bre-X, and you don't want to invest in it. See also Wall Street Journal.

First of all, Steve McIntyre - the mineral exploration analyst who has made the audit of the temperature reconstructions together with the economist Ross McKitrick - has a new blog

The tomorrow's (February 11th, 2005) issue of Science has an article by Richard Kerr that discusses two topics related to the "hockey stick graph":
  • The paper by McIntyre and McKitrick, soon to appear in Geophysical Research Letters, that shows that the reconstruction by Mann et al. is based on a flawed approach to statistics, and the results only reflect bristlecone pines
  • Another paper form today (February 10th, 2005) issue of Nature by the Swedish-Russian group led by Anders Moberg.
The paper of Moberg et al. leads to roughly 5 times bigger natural temperature fluctuations than the "consensus of the hockey team" - and roughly 2 times bigger than the biggest previous estimate. The shape does not look as a hockey stick at all. It shows a very warm period around 1100 and a cold period around 1600. Steve McIntyre says, among other things, that while Moberg et al. has been "a kick in the teeth of MBH, they have just made another spaghetti graph". ;-)

At any rate, the "scientific consensus" about the dominant role of "anthropogenic" global warming is definitely gone.

Previous articles about the hockey stick:

I suppose that the hardcore alarmists - those with a very strong stomach - will reply "It does not matter at all that all of our science is rubbish, we can still scare people". I predict that the toughest ones - those who don't feel any moral restrictions - will tell you once again that there will be 50 degrees Celsius heat in your city in the summer.

Well, that's unlikely unless you live somewhere in Sahara. The most likely way this could happen is that the ecoterrorists would do the same things like in Crichton's "State of Fear", and I hope that the U.S. army will be able to deal with them before they realize their plans.

The alarmists will tell you that even though all quantitative predictions, postdictions, and reconstructions have been proved flawed, there is still some effect of CO2 on the climate, and you should be scared. Yes, there is always some effect of any event on all events in its future light cone. But this, non-quantitative and proto-scientific fact cannot lead a rational person to any big conclusions.

A rational, scientifically oriented person or society needs to quantify the effects, determine its likely consequences, and quantitatively - and economically - calculate the best possible response. These "details" have been done incorrectly and must be re-done.

See also a recent article in The Economist:

Wednesday, February 09, 2005 ... Deutsch/Español/Related posts from blogosphere

Reall: Higher-dimensional black holes and rings

Harvey Reall gave an excellent job talk at MIT, and we could not have missed it. It was balanced because

  • he figured out the right equilibrium between simple results and non-trivial results - well, the talk was completely comprehensible
  • he divided the time correctly to talk about his own work and the work of others
  • he found the right balance between the string theory motivations and independence of string theory
Harvey is definitely among the world's leading experts in the field of solutions to higher-dimensional gravity and supergravity, especially the black hole solutions. Why do we care about the higher-dimensional solutions? It's harder to answer this question for a string-theoretical infidel.

But the rest of us knows: the Universe is probably higher-dimensional, and therefore it is a research of reality! And as Harvey emphasized many times, comparisons of a microscopic theory of quantum gravity with the predictions of classical (and semiclassical) general relativity is the next best thing after the experiment that we have to test a theory of quantum gravity, i.e. to test string theory.

The higher-dimensional black holes are also important because they can be the holographic dual description of some objects and phenomena in gauge theory - via Maldacena's AdS/CFT correspondence. And gauge theory is of direct physical relevance. For example, there exists the Hawking-Page first order phase transition for thermal gravity in anti de Sitter space: it's a transition between the thermal gas and a black hole. Edward Witten has explained that it corresponds to the confinement-deconfinement phase transition in the gauge theory.

Last female Dow Jones CEO fired

Many people focus on the percentage of women among the new tenured professors, which slipped below 15 percent, but no one cares about the world of business too much. Sheila Lennon explained in her article - published in many sources that require subscription - that the following story is not a feminist issue because its hero may be female, but she is also a greedy capitalist.

The Dow Jones industrial index is composed of 30 companies. Carly Fiorina has been the CEO of Hewlett-Packard for a couple of years - since 1999. She's a rather impressive person - she holds a bachelor's degree in medieval history and philosophy from Stanford, a MSc. degree from MIT, and an MBA from Maryland. She has been working for Cisco, Kellogg, Merck, Lucent, and AT & T.

Because she was just fired and replaced by Robert Wayman as interim CEO, all 30 Dow Jones companies have currently male CEOs.

All the computers I've bought in the last 10 years were Hewlett-Packard products - a desktop and laptops - which makes these developments a bit interesting for me. The main decision that Fiorina has been criticized for was her purchase of Compaq in 2002 that failed to increase the profits.

Monday, February 07, 2005 ... Deutsch/Español/Related posts from blogosphere

Goldston about fusion

For Windows users: have you already installed the February 2005 patches? There's a lot of them:

Today's physics colloquium at Harvard was about the fusion. Robert Goldston from Princeton did a very good job. The previous article about ITER and fusion on this blog was posted here, and many well-informed people added interesting comments for which I am grateful.

Goldston discussed a lot of physics issues connected with the stabilization of the plasma; magnetohydronamics (MHD); heat diffusion, and so on. The inflow of professional information was pretty fast. He described an equation due to David Bohm, and he distinguished the Bohm regime of the plasma from the gyro-Bohm regime. The Bohm regime is hopeless - the diffusion is far too strong. The gyro-Bohm regime is what will allow the fusion plants to operate, and they can show that this regime can be realized.

European constitution: NO

The new treaty to establish the Constitution of the European Union - which effectively means the proposed future European constitution - has roughly 353 pages. I guess that the fraction of the people who are gonna read it will be negligible.

Before I looked at the Czech translation of the document, my opinion was "70 percent against, 30 percent for". Now it is "95 percent against, 5 percent for". I would not say that it is a democratic constitution. Is started with all the symbols that usually define a country (although many people say that the EU would not be a single country), titles for all the national leaders and kings, and other fun stuff. After a couple of pages, it started to get closer to the essence. The text explained that the European laws would have higher priority than the national laws. The main organs of the EU should be

  • The European Parliament
  • The European Soviet
  • The Soviet of Ministers
  • The European Commission
  • The European Court

Well, I admit that my translation of some of these terms back to English is not the standard one (and others use the word "Council" instead of the "Soviet") - but mine is arguably the more appropriate one. The proposed text is full of clichés, but I don't care about this stuff. What is important is how the system is supposed to work.

Friday, February 04, 2005 ... Deutsch/Español/Related posts from blogosphere

Peace in Iran, LHC, and other news

Many readers rely on this blog as one of the main sources of information. Let's mention some news:

  • The US administration does not plan a war against Iran right now. Although Libertarian Girl and others may have presented some arguments supporting such a war (well, the photograph may be one of them), the Reference Frame would consider a war against Iran as a strategic error and a risky and morally controversial decision, especially after the less-than-perfect development in Iraq in the last 2 years. The plans about Iran may change, of course.
  • BBC has a new article about the search for the "God particle". Prof. Virdee says that "they don't always like theorists to tell them what they should find". Did you know that the Compact Muon Solenoid (CMS) is large enough to house the Canterbury Cathedral?
  • Max Schmeling (the boxer) died at age of 99. He may have been the greatest symbol of the "superior" Nazi race among the sport celebrities. However, from a historical perspective, I think that he was a kind of positive personality. He protected Jews from the Nazi regime, became friends with his old good African American competitor Joe Louis, and introduced CocaCola to West Germany.
  • Julia Tymoshenko, an ally of Viktor Yushchenko, became the new Ukrainian prime minister. The situation in Ukraine has been completely stabilized.
The weather has become one of the most politically sensitive topics ;-), which is the main reason why the Reference Frame finds it important to inform about the weather:
  • Although most of the news about the Arctic emphasize how warm it's getting and how the polar bears may dislike it, almost no one will tell you that the Arctic's stratosphere has experienced an extremely harsh, cold winter. In fact, this extreme cold is a threat for the ozone layer in Northern Europe. Unlike the "Global Warming", the ozone hole is viewed by the Reference Frame as a potential problem that should be seriously looked at; the UV radiation is dangerous, and its amount reaching the surface depends exponentially on the ozone layer's thickness. Of course, the Global Warming alarmists will blame everything - including the cooling stratosphere - on human-induced global warming, but I hope that most of my readers are still able to distinguish different effects. The ozone layer thinning is caused by many effects, and indirect effects of CO_2 are among the speculative ones.
  • Australia has had a record cold summer, too. Melbourne has recorded its coldest February day on record (12.8 degrees). It's been raining a lot. The damage has topped 100 million AUD. Also, a famous glacier in New Zealand had been used as a prime example of global warming - it shrunk by 500 meters between 1999 and 2003. The glacier was named after the emperor of my homeland, namely Austria-Hungary, 100+ years ago: Franz Josef. You won't hear about Franz Josef today because it is growing by 4 meters a day. This fact is apparently politically incorrect.
  • Today, it was announced that a new, fifty-kilometer-long iceberg has formed in the frigid waters around Antarctica.
  • Four days ago, Moscow was hit by the heaviest snowstorm ever. At the same day, a huge snowstorm also hit Japan.
  • Researchers have constructed realistic plans to terraform Mars, by injecting a huge amount of greenhouse gases to Mars's atmosphere. In other words, the scientists plan to use global warming to make another planet habitable. Well, CO_2 would not be enough: they think about fluorine-based gases that can be roughly 10,000 more efficient than carbon dioxide.
Some news from the economy:
  • The unadjusted unemployment in Germany has topped 5 million people, the highest number (and rate) since 1933 when Hitler took power: the number of unemployed jumped by 200,000 or so within a month. It may be useful, especially for some of the readers, to mention that it does not yet imply that a new Hitler has to become the German leader in 2005.
  • Europe is slightly changing its agenda. According to the previous, Lisbon agenda, various EU commission's governmental projects should have made our old good Europe the world's most dynamic economy by 2010. The new plan - the revised Lisbon agenda - is for Europe to avoid the collapse by 2010. The new commission's boss José Manuel Barroso (former Portugese prime minister) has obviously learned more from the failure of the Soviet bloc than his predecessors. He has made a kind of Larry-Summers-like scandal when he openly supported flexible free markets in his speech! :-) Barroso also wants to establish The Eurochusetts Institute for Technology.
  • In the US, the payrolls increased roughly by 150,000, a long-term average number and a disappointment for the economists who predicted 189,000. The unemployment calculated from another survey dropped from 5.4 to 5.2 percent, the lowest number since September 2001.
  • Václav Klaus, the outspoken and highly intelligent Czech President, spoke at the Microsoft conference in Prague. He explained that the clichés about the knowledge economy and information society are modern forms of mysticism. The important principles of market economy do not need any updates, and they are not correlated with any particular technology.
  • The financial terrorists at who believe that by having established a website for similar anti-Coke morons - a website that features virtual antimoney, they would be able to reduce the price of the Coca Cola stock from $40 to $20, must feel surprised. The airplanes do not land. The Coke stock has risen from $40 to $42.50 within the last few months.

Thursday, February 03, 2005 ... Deutsch/Español/Related posts from blogosphere

Tachyons can change topology

In the last 2 hours, Allan Adams just told us about his supernew paper

and because I think that it is definitely an interesting paper, let me say a couple of words.

Imagine that you take a type II string theory and compactify it down to 8 dimensions, on a two-dimensional genus "g" Riemann surface.

Well, unless "g=1", it is a non-conformal theory, so you will have to deal with a time-dependent background. Let's not worry. Let's assume the string coupling to be weak throughout the story.

Imagine that you start with a genus 2 Riemann surface. It can degenerate into two genus 1 Riemann surfaces connected by a thin tube. The circle wrapped around this tube is homologically trivial, and you can show that the fermions will be antiperiodic around it: it will be a Scherk-Schwarz/Rohm compactification on a thermal circle. The reason for the antiperiodicity is the same like the reason that the closed strings in the NS-NS sector must have antiperiodic boundary conditions for the fermions assuming that the corresponding operators in the "z" plane don't introduce any branch cuts.

OK, imagine that the tube is very long. Because of the antiperiodic boundary conditions, the sign of the GSO condition in the sectors with odd windings is reverted, and one can find some tachyons there assuming that the radius is small enough so that the winding is not enough to make the squared mass positive. Equivalently, one can T-dualize along the circumference of the tube to obtain some sort of type 0 theory which has a bulk tachyon if the radius in the type 0 picture is large enough. Go exactly near the point where the first tachyon in the "w=1" sector starts to evolve. It's the first perturbative instability you encounter.

Wednesday, February 02, 2005 ... Deutsch/Español/Related posts from blogosphere

Most articles support Summers

The last 24 hours may have been one of the first day-long periods in which the media mostly endorsed, not criticized, Larry Summers, and supported the freedom of speech and scientific inquiry. (Judging by the ensemble available at I mean the version of Lawrence Summers before he had to say what he finally said.

I expect the percentage to continue to rise. Why? It's simply because those who oppose Summers don't have too many things to say. In fact, they want nearly everyone to close their mouth (and lab, if it studies any details about the brain). Virtually all articles against Larry Summers may be summarized as follows:

  • The speech of Lawrence Summers was outrageous - everyone who has heard it should either black out or throw up. He has no right to speak in this way. Women are discriminated. You can see that they have a smaller representation in various professions - and most people (both men and women) believe that men are more likely to be successful in these professions. This proves that discrimination is everywhere around us because everyone with the right opinions about the world knows that the women are identical to the men, perhaps except for one organ. Note that this is not a circular argument because it is not a circular argument.
  • Why should we investigate the reasons behind the differences when we already have a holy, perfectly politically correct answer that has been prepared for us - namely discrimination - which is endorsed by all true believers in political correctness? Moreover, Summers' comments may convince some girls that the comments may be true. It's a complete catastrophe if someone knows something that can be true, and academia should prevent this threat. Note that Harvard University's logo even has "Veritas" isolated in a triangle which shows that everyone outside the triangle is safely protected not only from "Veritas" (the truth), but also from everything that could potentially become "Veritas".

Note that the newspapers could have saved a lot of money if they reposted this universal comment, instead of paying hundreds of authors of these mostly weak and uninteresting articles.

On the other hand, the articles that support Summers have much more to say and they are very diverse. The following list is kind of sorted from the newest ones:

  • Ana Veciana-Suarez - mother of 4 boys and 1 girl - boys will be boys
  • Readers - of International Herald Tribune - the gender differences are assets
  • Jeremy Beecher - Academia harmed by sound-bite culture; unpopular ideas will be unpopular even if they are true
  • Caitlin Hall - Harvard president makes valid point - there are also, as usual, brainless batallions of PC police calling for Summers' ouster
  • Cathy Young - Boston Globe - Summers spoke the truth; the real scandal is that Summers was forced to grovel to save his job
  • Matt Crenson - ABC news and a lot of other media - Summers's observations are not controversial among the experts
  • Vladimir Shlapentokh - a Russian-born professor from Michigan compares the politically correct prosecutors to Lysenkoist (anti-genetics) and the proponents of intelligent design; Summers, lacking the courage of Giordano Bruno, ...
  • Readers of New York Post - all three are supporting Summers; PC movement preferes to stifle debates; the contrition tour is getting sickening - that crowd can't be appeased
  • Stephen Braun - L.A. Times - brilliant and abrasive Summers ... (neutral article)
  • Georgie Ann Geyer - one of the most experienced feminists agrees with Summers: "fair" does not mean "same"
  • Michael Lewis - Bloomberg - Summers is the only thoughtful, interesting president, the only one who is not a coward; he assumed that the women were his peers who were looking for the truth and they did not appreciate it
  • Christopher Caldwell - Financial Times - "I know of no community as committed to free inquiry as this one," wrote Larry Summers even though he had almost lost his job because of his commitment to free inquiry
  • Warren Coats - let's not the truth, whatever it is; we are individuals, not averages
  • Mark Ayoub - in defense of an arrogant male chauvinist
  • Aljazeera - repeats the Reuters story (Summers is exhibit A...) and introduces it with a picture saying "restrictive laws are inhibiting academics in the United States"
  • Washington Post - an editorial opinion - it's a university's function to provoke fresh thinking, especially about big issues that are "too important to sentimentalize", as Summers rightly puts it
  • Margaret Carlson - L.A. Times - Summers is brilliant
  • New York Post - Harvard's thought police
  • Kathleen Parker - about womanhood
  • Mike North - genders are different and water is wet
  • Arnold Kling - four standard deviations in the distribution; about Kling's daughter who had to answer "yes" to the question "Is gender socially determined?" - I kid you not; shame on Summers's critics, praise to his defenders; discrimination damages the discriminator; self-regarding attribution bias; male dominance
  • Elie Dvorin - Academic hypocrisy - comparing Churchill and Summers
  • Zach Musgrave - U. of Washington - Summers not sexist - What is really at stake is academic freedom
  • Phyllis Schlafly - The feminists who have no sense of humor ... lassoed Summers and dragged him ... Communists used to punish ... but feminists took it to new heights ... When will American men learn how to stand up to the nagging by the uncivil feminists whose sport is to humiliate men?
  • CNN - Male and female brains different - it's as easy as X and Y - about 100 structural differences known
  • Dan Byrne - Michigan needs someone like Summers - this man is brilliant
  • Free Lance Star - Sexes are different, it's simple biology - a scary story of David whose penis was removed. David became Brenda, they celebrated that he became a woman. But as far as his brain went, these were just feminist lies. He continued to be David. He was thinking as a man. He became a man again, and later commited suicide
  • Brenda Maddox - the Guardian (British socialist newspaper) - nicely written short biographies of important women in science - and how the feminists hijacked Rosalind Franklin
  • Chuck Colson - Denying the obvious
  • Stuart Taylor - Why feminist careerists neutered Larry Summers
  • Bill O'Reilly - About radicalization of faculties
  • John Leo (Alan Greenspan's twin) - What Larry meant to say
  • The Age - Australia - sexes innately different - unless you are PC, steer clear of Harvard
  • Kara Falchini - women in average are weaker in football and different in math.
  • Walter Williams - Anti-intellectualism among the academic elite - very informative; also studies how genetic differences correlated with sexual orientation and races affect various things, and what people think (and like to think) about these issues. Note that the author is African American. Reprinted in Townhall, DC; Worldnetdaily, OR; Washington Times.
  • Gill Spencer - takes an example of Nancy Hopkins; the 13:1 boys:girls ratio for the math score above 700 as evidence of differences. Also mentions that Larry Summers has female-like empathy and verbal skills. ;-)
  • Daniel Koffler - from Yale - why equal isn't identical; "the irony at Hopkins' expense is that she is presenting herself as a caricature of the helpless, constantly-fainting Victorian "woman of the house." If feminism is to have any point at all, ..."
  • Human Events - "What’s not 'up for discussion,' in short, is what’s politically incorrect." - Also talks about 4% - which is the percentage of ... registered Republicans plus Libertarians at Harvard. This is a *real* underrepresentation - but this one is apparently politically correct.
  • James Koch - professor - Summers should not be gagged
  • Daily Californian - Sex and the university - "this political environment stifles free speech and ideas."
  • Seattle PI - Does one gender do better? - A lot of graphs and data about the brain differences and jobs, with overall conclusions that should not offend anyone.

This is just the last 24 hours or so. The number of articles that support Lawrence Summers and his points is roughly 300+ (many of them being copies of others), with the same number of articles that mostly oppose his comments. Some articles from the previous day or so:

  • Dan Thomasson - Nature or Nurture? - "When Harvard President Lawrence Summers injudiciously defied the Gods of Political Correctness by suggesting..."
  • Concord Monitor - "...Summers grovels before the goddesses of hyper-political correctness..."
  • Reuters - IQ related area may differ between men and women - some details packaged to a package that should not offend anyone
  • Human events - by Mac Johnson - Summers speaks truth, then apologizes
  • Feminists, meet Mr. Darwin - Robert Wright accused those who deny innate differences of holding "patently false beliefs about human nature."
  • Robyn Blumner - Hysteria in the ivory tower - "Alternative explanations are no longer welcome. This should be distressing to people who care more about uncovering the truth than assuaging hurt feelings.". The same article with a photograph appears here. I guess that many readers of my blog will study the correlation between the beauty of the female authors and their agreement with Summers, and I'm afraid that the signal they find will be striking.
  • Barbara Simpson - Maybe it's time to be afraid - about the freedom of speech and poor Larry (I'm putting it here because there is a photograph here, too) ;-)
  • Diana West - Ladies, please... - "I hate 'women', those who make a career out of it..."
  • Shawn Augsburger - UC Irvine - Summers entitled to free speech - differences between brains...

Tuesday, February 01, 2005 ... Deutsch/Español/Related posts from blogosphere

Crossbar latch & fast computers

This looks like an impressive discovery in nanophysics. Today, Hewlett-Packard has announced in Journal of Applied Physics

that they invented a "crossbar latch", a new cheap, nanometer-sized component at the molecular level that has the potential to replace the transistors and speed up the computers by three orders of magnitude.

The patent was actually registered already in 2003:

It will probably take years before the new computers can be developed using this technology, if it ever happens.

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