## Monday, July 31, 2006

### Germany, theoretical physics, and string theory

DEUTSCH

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

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

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

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

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

German-speaking string theorists

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

• Wolfgang Lerche who has together with Dieter Lüst and Bert Schellekens, among many other things, proposed the huge number of the stringy vacua 20 years before it became fashionable to talk about them
• Katrin Becker
• Melanie Becker (both sisters wrote not only great research papers but also a new string theory textbook with John Schwarz that you simply can't miss)
• Julius Wess, a supersymmetry expert and co-author of a famous book
• Axel Krause who is an expert in heterotic superstring phenomenology
• Volker Braun who likes to construct heterotic Standard Models
• Herman Nicolai who is a key player in the supergravity community, one that has fully merged with the string theory community after the discovery of M-theory
• Andreas Karch who is a famous superstring phenomenologist and a co-author of some well-known papers with Lisa Randall, among many others
• Dieter Lüst who is incidentally also the first co-author of a string theory textbook (link)
• Susanne Reffert, a charming expert in algebraic geometry and flux compactifications
• Urs Schreiber (blog) who enjoys gerbes and category theory and tries to reveal their role in string theory
• Niklas Beisert who loves spin chains in AdS-CFT
• Raphael Bousso, the prince of holography, who was born in Israel but otherwise is connected with Bavaria
Because you will surely be able to find the information about the people yourself, let me add a few names without a description:

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

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

Intellectual conservatism of the Central European science

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

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

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

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

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

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

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

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

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

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

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

Summary

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