The ICMP 2006 will start in Rio de Janeiro tomorrow. It is a traditional meeting which began in Moscow in 1972 and is held each three years. During the conference the Poincare Medal is awarded and this year I heard it will go to Ludvig Faddeev. There are several other satellite meetings going on or ending now, like the Workshop on Pure Spinors organized by Nathan Berkovits in Sao Paulo.
yesterday and today it is happening the Young Researchers Symposium, a meeting promoted by the ICMP to attract younger people and where a Field medalist gives a talk. This year this seminar will be delivered by E. Witten.
The symposium started yesterday with a very nice talk by Faddeev on quantum groups. As he explained quantum groups are neither quantum nor groups. They are deformations of the phase space and the group structure. He started with spin chains using the XXX Heisenberg model along the lines of his well known review. He went on to the XXZ model and its connection with deformed algebras, Yang-Baxter, braid groups, and so on. During the talk he gave many historical accounts related to the subject and distributed a copy of a new preprint "History and Perspectives of Quantum Groups". Very interesting.
Berkovits gave a talk about string amplitudes and pure spinors. Too technical for an audience of mathematicians and physicists from several areas. Anyway it is too hard to explain his goal without going into the technical details. At the end he said that it is possible to extend his pure spinor formalism to 11 dimensions and maybe get more information on M theory. The talk of David Ruelle went the other way. Almost no equations. Too difficult to understand many of his statements and the line of reasoning. Maybe for people working in the area it was easier. He talked about dynamical systems, chaos, turbulence and nonequilibrium statistical mechanics. He told that the solar system is not stable and some guys in the audience seemed very worried about that! Many historical notes were told mainly about Poincare. Like the butterfly effect that had in fact begin with a seagull and not with a butterfly.
There were other sessions where younger people presented their work. The day ended with a reception and Brazilian music, chorinho and samba. Very good.
06 August 2006
04 August 2006
Why progress in science is so slow around here
Lubos Motl wrote a post trying to understand why Germany, and more generally Central Europe, after giving so many contributions to physics in the early XX century lost the leadership. He identifies three causes:
1. The American financial attractor that has caused some brain drain
2. The working American free market of ideas and its less viable European counterpart
3. The relative inability of European scholars to allow their younger colleagues to get further
It is interesting to realize that all this holds also for Brazil and possibly for Latin America. Maldacena is by far the most clear example of the first point. Even if he wanted to go back to Argentina it would be very difficult for the other reasons.
Lubos also details the other two points:
In the American system, new ideas are actively looked for and they are appreciated, together with their happy authors. In the Central European context, it is more important to be compatible with the old ideas - let us call them "perfectly balanced ideas" - that are currently dominating the intellectual landscape and in which the old myths and pre-conceptions play a comparable role to the newest developments.
and,
The third difference between America and Central Europe that I mentioned is the insufficient desire of the Central European scholars to support their students and younger colleagues in getting further than the previous generations. A particularly bad habit is to penalize students and others for being interested in and working on new ideas.
Reading this brings recollections from many years ago. When I was a MSc student, in the 70's, the preprints I read were saying that quantum field theory was the framework for elementary particle physics. The researchers I talked to said that it was just a fashion and it would go away. I could not understand why. After all there were experimental evidence supporting QFT. So I had to study QFT by myself and I did so. After the PhD in London I came back to Brazil at the beginning of the 80's. I recall giving several talks on supersymmetry. It was usual to hear comments like this:
- You should do research in supersymmetry only after it is found, not now.
I usually replied saying that when supersymmetry is found it will no longer be the subject of research but of textbooks. As we all know susy is likely to be found at LHC and even before its discovery it is already in textbooks! A colleague of mine already deceased, P.P.Srivastava, was one of the first people to work in conformal supersymmetry. He was in Europe when he did his work but had to return to Brazil. Here he was convinced by many Brazilian researchers that supersymmetry was just a fashion which would go away soon. Unfortunately he gave credit to this argument and stopped working in susy. Being out of scene people started to stop citing his works. Some years later he realized how wrong his decision was, went back to susy and wrote a book Supersymmetry, Superfields and Supergravity in an attempt to get credit for having worked in conformal susy. His book was one of the few available at that time and is quite good.
Things like this happened in other areas as well. Still in the 80's, when the inflationary theory was born, people working in general relativity in Brazil started to despise the idea. They used to compare the researchers of inflation with those old Hollywood western movies where an old guy in the back of his wagon sells a miracle medicine fooling everybody! That is how it works in many places. If you do not have sound scientific arguments you convince people in this way. Mainly if you live in an economically or militarily oppressed country. It works! I had a bad time explaining to young students the distinction between scientific ideas and political ideologies.
Of course, string theory was also a target for these people. Take Nathan Berkovits for instance. He applied for a position in my institute in the 90's. We discussed the CV and recommendation letters of all candidates. Nathan had a very strong recommendation letter from Witten. After some harsh discussions an influent professor said:
- Who is this Witten anyway?
I immediately said
- The same who just won the Fields Medal!
And he replied in a waggish way
- But his work was in geometry not in analysis!
That was the feeling against string theory at that time! A committee was chosen to select one of the candidates and obviously Nathan did not get the position. Very soon, another university in Sao Paulo, run by younger and smarter people, hired him so he got a good position and is well now. But we lost Berkovits!
Another tactics that is often used consists in bringing foreign people to say the last word against new ideas. There is a well known retired German professor who thinks that we all should do field theory like in 60's and forget everything about string theory. Fortunately almost nobody takes this sort of foreign authority seriously nowadays.
It has to be said that this kind of people is no longer representative of physics in Latin America. As the time goes by their proportion is diminishing in Brazil and they are loosing any decision power they had before. There are many serious researchers who appreciate new ideas and work on them. Some may not work on modern topics but accept that others do so. Without any embarrassment or any mocking. Students now can choose their area without being oppressed. And more than that, they are free to do better than their former teachers did.
A warning to the students. Some of this people are still around. You can easily recognized them. Do not trust those who attack a subject without any solid scientific argument. Never accept political or sociological arguments. They were wrong in the past. And they will be always wrong.
We are slowly finding our way to do leading science.
1. The American financial attractor that has caused some brain drain
2. The working American free market of ideas and its less viable European counterpart
3. The relative inability of European scholars to allow their younger colleagues to get further
It is interesting to realize that all this holds also for Brazil and possibly for Latin America. Maldacena is by far the most clear example of the first point. Even if he wanted to go back to Argentina it would be very difficult for the other reasons.
Lubos also details the other two points:
In the American system, new ideas are actively looked for and they are appreciated, together with their happy authors. In the Central European context, it is more important to be compatible with the old ideas - let us call them "perfectly balanced ideas" - that are currently dominating the intellectual landscape and in which the old myths and pre-conceptions play a comparable role to the newest developments.
and,
The third difference between America and Central Europe that I mentioned is the insufficient desire of the Central European scholars to support their students and younger colleagues in getting further than the previous generations. A particularly bad habit is to penalize students and others for being interested in and working on new ideas.
Reading this brings recollections from many years ago. When I was a MSc student, in the 70's, the preprints I read were saying that quantum field theory was the framework for elementary particle physics. The researchers I talked to said that it was just a fashion and it would go away. I could not understand why. After all there were experimental evidence supporting QFT. So I had to study QFT by myself and I did so. After the PhD in London I came back to Brazil at the beginning of the 80's. I recall giving several talks on supersymmetry. It was usual to hear comments like this:
- You should do research in supersymmetry only after it is found, not now.
I usually replied saying that when supersymmetry is found it will no longer be the subject of research but of textbooks. As we all know susy is likely to be found at LHC and even before its discovery it is already in textbooks! A colleague of mine already deceased, P.P.Srivastava, was one of the first people to work in conformal supersymmetry. He was in Europe when he did his work but had to return to Brazil. Here he was convinced by many Brazilian researchers that supersymmetry was just a fashion which would go away soon. Unfortunately he gave credit to this argument and stopped working in susy. Being out of scene people started to stop citing his works. Some years later he realized how wrong his decision was, went back to susy and wrote a book Supersymmetry, Superfields and Supergravity in an attempt to get credit for having worked in conformal susy. His book was one of the few available at that time and is quite good.
Things like this happened in other areas as well. Still in the 80's, when the inflationary theory was born, people working in general relativity in Brazil started to despise the idea. They used to compare the researchers of inflation with those old Hollywood western movies where an old guy in the back of his wagon sells a miracle medicine fooling everybody! That is how it works in many places. If you do not have sound scientific arguments you convince people in this way. Mainly if you live in an economically or militarily oppressed country. It works! I had a bad time explaining to young students the distinction between scientific ideas and political ideologies.
Of course, string theory was also a target for these people. Take Nathan Berkovits for instance. He applied for a position in my institute in the 90's. We discussed the CV and recommendation letters of all candidates. Nathan had a very strong recommendation letter from Witten. After some harsh discussions an influent professor said:
- Who is this Witten anyway?
I immediately said
- The same who just won the Fields Medal!
And he replied in a waggish way
- But his work was in geometry not in analysis!
That was the feeling against string theory at that time! A committee was chosen to select one of the candidates and obviously Nathan did not get the position. Very soon, another university in Sao Paulo, run by younger and smarter people, hired him so he got a good position and is well now. But we lost Berkovits!
Another tactics that is often used consists in bringing foreign people to say the last word against new ideas. There is a well known retired German professor who thinks that we all should do field theory like in 60's and forget everything about string theory. Fortunately almost nobody takes this sort of foreign authority seriously nowadays.
It has to be said that this kind of people is no longer representative of physics in Latin America. As the time goes by their proportion is diminishing in Brazil and they are loosing any decision power they had before. There are many serious researchers who appreciate new ideas and work on them. Some may not work on modern topics but accept that others do so. Without any embarrassment or any mocking. Students now can choose their area without being oppressed. And more than that, they are free to do better than their former teachers did.
A warning to the students. Some of this people are still around. You can easily recognized them. Do not trust those who attack a subject without any solid scientific argument. Never accept political or sociological arguments. They were wrong in the past. And they will be always wrong.
We are slowly finding our way to do leading science.
03 August 2006
30 July 2006
Bolhas de nada
Bolhas de nada, literalmente bubbles of nothing, é algo que frequentemente aparece em teoria de cordas mas sua origem é mais antiga. Está associado ao possível decaimento não perturbativo de espaço-tempos instáveis. Uma boa descrição desse processo está descrita em Bubbles of "nothing". Para os que nunca ouviram falar sobre vácuos não perturbativos talvez seja melhor ler primeiro algo sobre instantons.
26 July 2006
Ghostly photons, axions or noncommutativity?
In March the PVLAS collaboration in Italy found a small polarization rotation when a laser beam went through a region with a large magnetic field. See here. The result can be interpreted as photons turning into axions, a still unobserved particle associated with the conservation of CP symmetry in strong interactions. Axions have no electric charge, a very small mass, and interact very weakly through the strong and weak forces. A very difficult guy to be detected!
Now DESY is planning an experiment using the FLASH, a machine which produces an extremely bright laser beam. The laser will go through a region with intense magnetic field and will be stopped by a wall. In the magnetic field some photons will turn into axions, like in the PVLAS experiment, pass through the wall, and another magnetic field on the other side of the wall will turn these axions back to photons. So photons will apparently come through the wall like ghosts (not the Faddeev-Popov ones!). Very clever! The proposal is here. They are planning to start the experiment by the end of 2006.
If the effect is real and if no axions are found an alternative explanation could be noncommutativity. A noncommutative photon acquires a phase in an electromagnetic background. This causes a rotation in the polarization as observed in PVLAS collaboration. In the DESY experiment no photons would be observed through the wall. That would be great!
Now DESY is planning an experiment using the FLASH, a machine which produces an extremely bright laser beam. The laser will go through a region with intense magnetic field and will be stopped by a wall. In the magnetic field some photons will turn into axions, like in the PVLAS experiment, pass through the wall, and another magnetic field on the other side of the wall will turn these axions back to photons. So photons will apparently come through the wall like ghosts (not the Faddeev-Popov ones!). Very clever! The proposal is here. They are planning to start the experiment by the end of 2006.
If the effect is real and if no axions are found an alternative explanation could be noncommutativity. A noncommutative photon acquires a phase in an electromagnetic background. This causes a rotation in the polarization as observed in PVLAS collaboration. In the DESY experiment no photons would be observed through the wall. That would be great!
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