Short Items

Posted on January 2, 2014 by woit
  • Harvard has announced that the Chinese firm Evergrande Group will be supporting various activities at Harvard, including a new Center for Mathematical Sciences and Applications, with S.-T. Yau as director. No details of what the center will do other than “serve as a fusion point for mathematics, statistics, physics, and related sciences.” The company has its own announcement here (they might want to check on the name of Harvard’s President…).
  • The new Physics Today has an article Paul Ehrenfest’s final years, a sad bit of physics history I’d never seen the details of.
  • Last month in Moscow there was a conference for Boris Feigin’s 60th birthday. Videos of the talks are now available here.
  • Dick Gross’s wonderful lecture series here at Columbia on Representation theory and number theory has been available on video since he gave the lectures. Now Chao Li at Harvard has produced a transcription of the talks, so a high-quality written version of the material of the lectures is now available. This is one of the best sources around to learn about the local Langlands conjectures. His website contains a lot of other interesting expository material.
  • Phenomenologist Jay Wacker has a blog at Quora, called Particle Physics Digressions. The latest entry is an odd tale of something I would have thought was rather unusual, but Wacker says it’s not exceptional, happens everyday.
Posted in Uncategorized | 20 Comments

Acknowledgments

Posted on December 30, 2013 by woit

Two of the prominent string theorists working on ideas about holography and cosmology featured in Amanda Gefter’s new book are Tom Banks and Willy Fischler, who have a new paper out on the subject, entitled Holographic Space-time and Newton’s Law. Besides the usual sort of thing, this paper contains a rather unusual acknowledgments section (hat-tip, the Angry Physics blog):

The work of T.B. was supported in part by the Department of Energy. The work of W.F. was supported in part by the TCC and by the NSF under Grant PHY-0969020. However, the authors do not thank either of these agencies, nor their masters, for the caps placed on their summer salaries, nor for the lack of support of basic research in general.

It seems that while debating philosophical issues concerning holography and cosmology can put one at the upper end of the current academic star system pay scale, it doesn’t stop one from getting embittered that it’s not enough. The authors did revise this text a few days later to remove the complaints.

For those who don’t know what this is all about, prominent theoretical physicists (and mathematicians) in the US generally have research grants that pay them not only research expenses, but “summer salary”. Historically, the reasoning behind this was that academics needed to teach during the summer to make ends meet, so agencies like the NSF would get them more time to do research by paying them to not teach. That was long ago, in a distant era. At this point the typical sums universities pay for summer courses are so much smaller than the academic-year salaries of successful senior academics that few would consider dramatically increasing their teaching load this way to make a little extra money.

Taking the NSF as an example, the standard computation is that an academic’s salary is considered just pay for nine months, with the NSF allowing grants to pay for up to two months of summer salary. In other words, grant applications can include a request for 2/9ths of a person’s salary, to be paid as additional compensation in return for not teaching summer school. As the salaries of star academics (who are the ones most likely to get grants) have moved north of 200K/year, these additional salary amounts have gotten larger and larger, crowding out the other things grants pay for (post-doc salaries and grad-student support are the big items).

Several years ago the mathematics part of the NSF instituted a “salary cap” on these payments, limiting them to about \$25K/year. This year, in response to declining budgets, such a cap was put on payments to theoretical physicists, at \$15K/month. So, any theorist with an academic year salary of over $135K/year saw a reduction in their additional compensation (although as far as I know only two were so outraged by this that they complained in the acknowledgments sections of their papers). The report of this year’s panel on the future of particle theory in the US includes the language:

This past year, the DOE instituted caps on summer salaries, and the NSF is following suit. We agree that this is preferable to further cuts in student and postdoctoral support, but it should be noted that still lower caps will have implications for research productivity, particularly if they reach the level of junior faculty (assistant or associate professor salaries). Many researchers may have to supplement their income with further teaching or other responsibilities in the summers.

Since Banks and Fischler work at public universities, one can check for oneself that they are seriously impacted by the new caps. Fischler is at the University of Texas, Banks has positions at UC Santa Cruz and Rutgers (I have no idea how the two institutions split his salary). Some of the grant information is also publicly available, for instance the NSF grant referred to in the acknowledgment is this one. It expires soon, but was supposed to provide \$690K over three years, presumably including summer salary for Fischler, Weinberg and three others. One anomaly here is Weinberg, who at over $500K/year is likely the highest paid theorist in the US. The same people have a new grant recently awarded, for \$220K.

Posted in Uncategorized | 32 Comments

Trespassing on Einstein’s Lawn

Posted on December 29, 2013 by woit

Amanda Gefter, a science writer who has often covered theoretical physics topics for New Scientist, has a new book coming out soon, Trespassing on Einstein’s Lawn. On one level it’s a memoir, telling a story that begins with her father getting her interested in fundamental questions about physics. This led to a career interviewing well-known physicists and writing about these topics, and now, a book. Self-reflexivity is a major theme of the book, with one aspect of this the way it tells in detail the story of its own genesis and creation.

In many ways, it’s comparable to last year’s book by Jim Holt, Why Does the World Exist?, with both books motivated by versions of the question “Why is there something rather than nothing?” In both books, there’s a memoir aspect, with the author front and center in a search for answers that involves meetings and discussions with great thinkers. For Holt, these were mostly philosophers with a few physicists thrown in, while for Gefter they’re mostly physicists, with a few philosophers making an appearance. These are lively, entertaining writers with wonderful material about deep questions, and I greatly enjoyed both books. Gefter is the funnier of the two, and I had trouble putting the book down after it arrived in my mail a couple days ago.

For those familiar with the topics she covers, the descriptions of her encounters with famous physicists is what will most likely provide something new. A few examples:

  • She somehow managed to get to moderate a private debate between Lenny Susskind and David Gross, mainly on the topic of the multiverse. Much of the result is familiar to anyone following the topic over the last ten years (Gross detests the multiverse, Susskind is madly in love with it), but one interesting aspect is Gross’s comparison of Susskind’s behavior to his own back in 1984-5:

    What I’m saying… is that some of the reaction is exactly like the reaction I got for exuberance in 1984, when we believed the answer was around the corner and we got carried away with that position. And, Lenny, you are carried away with this position. The stakes are damn big. So you are open to severe criticism.

    So, it seems that Gross is accusing Susskind of engaging in hype deleterious to physics, while acknowledging that he did much the same thing to get string theory unification off the ground and widely accepted.

  • Several string theorists pointed out that strings themselves have pretty much disappeared from the story. The emphasis is now on the holographic principle and the hope for some unknown M-theory that embodies it. About M-theory, Polchinski has this to say:

    It’s remarkable to know so much about many limits and yet have no good idea of what they are limits of! Holography is clearly part of the answer. The fundamental variables are probably very nonlocal, with local objects emerging dynamically.

    Witten tells Gefter that the “M” in “M-theory” really was intended to refer to membranes. He doesn’t see much happening though as far as new ideas about understanding it:

    …in the mid-eighties and mid-nineties, before the second revolution happened, there were kind of hints that something was going to happen – I didn’t know what, of course. I don’t have that feeling now, but perhaps other people do… If I had my druthers I’d like to go deeper into what’s behind the dualities, but that’s really hard.

  • John Wheeler plays a large role in Gefter’s story, which starts with her asking him a question at this conference in 2002. She has a fascinating description of Wheeler’s journals, which have been preserved in Philadelphia, where she and her father spent quite a lot of time looking through them.

The list of interviewees includes also Kip Thorne, Raphael Bousso, Tom Banks, and Carlo Rovelli.

Gefter makes it clear that she started out with essentially no background in physics or math, other than enthusiasm shared with her father for speculation about “nothingness” and the like. She studied not physics, but philosophy of science at the London School of Economics. Despite this lack of technical training, she does a good job of accurately characterizing what the physicists she talked to had to say. Towards the end the book does suffer a bit as she moves away from reporting what others are telling her to expounding her own interpretation of what it all means.

While I liked the book, at the same time I found the whole project deeply problematic, and would have reservations about recommending it to many people, especially to the impressionable young. The part of physics that fascinates Gefter is the part that has gone way beyond anything bound by the conventional understanding of science. This is really and truly “post-modern physics”, completely unmoored from any connection to experiment (the discovery of the Higgs in the middle of the period she is writing about just gets a short footnote). The questions being discussed and answers proposed are woolly in the extreme, focused on issues at the intersection of cosmology and quantum mechanics, suffering from among other things our lack of a convincing quantum theory of gravity. Gefter seems to be sure that the problem of quantum gravity is an interpretational one of how to talk about a quantum cosmology where observers are part of the system. The very different, much more technical issue of how to consistently quantize metric degrees of freedom in a unified way with the Standard Model fields is ignored, perhaps with the idea that this has been solved by string theory.

Not recognizing that this post-modern way of doing science is deeply problematic and leading the field into serious trouble isn’t so much Gefter’s fault as that of the experts she speaks to (David Gross is an exception). Those taking the field down this path are dominating public coverage of the subject, and often finding themselves richly rewarded for engaging not in sober science but in outrageous hype of dubious and poorly-understood ideas. Only the future will tell whether the significance of this book will end up being that of an entertaining tale of some excesses from a period when fundamental physics temporarily lost its way, or a sad document of how a great science came to an end.

Posted in Book Reviews | 11 Comments

Trust the math? An Update

Posted on December 21, 2013 by woit

Back in September, I wrote here about the news that Snowden’s revelations that confirmed suspicions that back in 2005-6 NSA mathematicians had compromised an NIST standard for elliptic-curve cryptography. The new standard was promoted as an improvement using sophisticated mathematical techniques, when these had really just been used to introduce a backdoor allowing the NSA to break encryption using this standard. There still does not seem to have been much discussion in the math community of the responsibility of mathematicians for this (although the AMS this month is running this opinion piece).

After my blog post, some nice detailed descriptions of how this was done and the mathematics involved appeared. See for instance The Many Flaws of Dual_EC_DRBG by Matthew Green, and The NSA back door to NIST by Thomas Hales. The Hales piece will appear soon in the AMS Notices. Hales also has a more recent piece, Formalizing NIST Standards, which argues for the use of formal verification methods to check such standards. Also appearing after my blog post was the news that RSA Security was now advising people not to use one of its products in default mode, the BSAFE toolkit.

One mystery that remained was why the NIST had promulgated a defective standard, knowing full well that experts were suspicious of it. Also unclear was why RSA Security would include a suspicious standard in their products. Back in September they told people that (see here) they had done this because:

The hope was that elliptic curve techniques—based as they are on number theory—would not suffer many of the same weaknesses as other techniques

and issued a statement saying:

RSA always acts in the best interest of its customers and under no circumstances does RSA design or enable any backdoors in our products. Decisions about the features and functionality of RSA products are our own.

Today there are new revelations about this (it’s unclear from what source), which explain what helped make RSA swallow the bogus mathematics: a payment from the NSA of \$10 million. I guess there’s a lesson in this: when you can’t figure out why someone went along with a bad mathematical argument, maybe it’s because someone else gave them \$10 million…

Update: For another explanation of the math behind this, see videos here and here featuring Edward Frenkel.

Update: There’s a response to the Reuters story from RSA here. As I read it, it says

  • They do have a secret contract with the NSA that they cannot discuss
  • They used the NSA back-doored algorithm in their product because they trust the NSA
  • They didn’t remove it when it became known because they really are incompetent, not because the NSA was paying them to act incompetent

It’s hard to see why anyone would now trust their products.

Posted in Uncategorized | 27 Comments

Latest on abc

Posted on December 19, 2013 by woit

In case you haven’t been following this story, “abc” refers to a famous conjecture in number theory, for which Shin Mochizuki claimed last year (see here) to have found a proof. His argument for abc involves a new set of ideas he has developed that he calls “Inter-Universal Teichmuller Theory” (IUTeich). These are explained in a set of four papers with a total length over 500 pages. The papers are available here, and he has written a 45 page overview here. One can characterize the reaction to date of most experts to these papers as bafflement: what Mochizuki is doing is just so far removed from what is known and understood by the experts that they have no way of evaluating whether or not he has a new idea that solves the abc problem.

In principle one should just be able to go line by line through the four papers and check the arguments, but if one tries this, one runs into the problem that they depend on a long list of “preparatory papers”, which run to yet another set of more than 500 pages. So, one is faced with an intricate argument of over 1000 pages, involving all sorts of unfamiliar material. That people have thrown up their hands after struggling with this for a while, deciding that it would take years to figure out, is not surprising.

Mochizuki has just released a new document “concerning activities devoted to the verification of IUTeich”. It explains the state of his efforts to get other mathematicians to check his work, a project that has been going on since last year, leading to many ongoing updates to the papers making up the proof. He explains that he submitted the four IUTeich papers to a journal last August, but will not have anything to say about the journal or the state of the submission process. This is the way mathematics is supposed to work: the papers should be refereed by experts who have agreed to go through and check them carefully (and confidentially). Given the unusual character of the series of papers, finding willing and able referees may be very difficult. It would of course be most satisfying if such referees can be found and can either identify holes in his argument, or vouch for correctness of the whole thing.

In the meantime, he has been working since October 2012 with Go Yamashita, who has carefully gone through the papers and is now writing a 200-300 page survey of what is in them. Yamashita may also give a course on the topic at Kyushu University sometime after next April. As part of this process, three other mathematicians participated in a seminar in which Yamashita lectured on the papers.

Another mathematician working on this is Mohamed Saïdi, who devoted about six months to studying the papers, then spent three months visiting Kyoto and discussing them with Mochizuki. According to Mochizuki, he has said that he believes the theory to be correct. Mochizuki summarizes the current situation as

the issue of whether or not one should regard the verification of IUTeich as being, for all practical purposes, complete, i.e., as a result of the activities of Yamashita and Saïdi, is by no means clear, and any sort of “final conclusion” on this topic must be regarded as a matter that lies beyond the scope of the present report.

Mochizuki goes on to claim that, based on what he has heard from Yamashita and Saïdi, researchers trying to read his papers should find it possible to understand the theory if they work on it for roughly half a year. He warns that they do need to be aware though that an attempt to make sense of what he is doing by expecting “a similar pattern of argument to existing mathematical theories is likely to end in failure.” They also need to keep in mind that he’s not particularly focused on proving abc, that for him it is the IUTeich theory itself that is the object of interest.

This is a remarkable story, with little precedent. After more than a year, I haven’t heard anyone willing to bet either way on how it will turn out. Mochizuki is a talented mathematician and maybe he has a proof. Or maybe he has a complicated set of ideas which don’t do what he hopes. Perhaps someday one of these alternatives will start to emerge, but it doesn’t now look like this will be anytime soon.

Posted in abc Conjecture | 32 Comments

A Bubble-Universe at Stanford

Posted on December 19, 2013 by woit

Video from last weekend’s Fundamental Physics Prize scientific meeting at Stanford is now available, in unedited form, here.

The first video there is a discussion moderated by Yuri Milner, who does a good job of asking Strominger, Polchinski, Green, Schwarz and Vafa questions, although getting pretty much exactly what you’d expect out of them (the hot topic is firewalls).

After skimming through the rest of several hours of video, what struck me is that Milner has managed to all by himself implement the bubble-universe picture of reality that has been propounded at Stanford for many years by Linde, Susskind and others. By smashing tens of millions of dollars into a small target (some prominent academics), he has created a new bubble-universe, with new laws of physics and a new conception of science. In this particular bubble-universe, problems with string theory unification have magically vanished and don’t need to be mentioned. Whether a scientific theory can predict anything or not is irrelevant, since you just know what has to be true (the idea with the big money attached to it). The embarrassing fact of no SUSY at the LHC does get fleeting mention, but John Schwarz assures everyone that in his view, there is no question that superpartners exist, whether or not the LHC ever sees them. The multiverse is seen as the answer to all problems, although Cumrun Vafa does warn that maybe one should also look for other answers. Polyakov says that he has nothing against this kind of “Anthropology”, except that it is very boring. That’s an accurate characterization of the science of the new bubble-universe at Stanford.

Most remarkable is the last video, where things truly become causally disconnected from the universe outside Stanford. After a long introduction from Susskind, Michael Green takes the stage with a talk recapitulating the entire history of science, with string theory the successful culmination of this history. He and Schwarz then settle in to accept congratulations from the audience for their great discovery that has made the bubble-universe possible.

Posted in Multiverse Mania | 5 Comments

Milner-Zuckerberg Prizes for Mathematics

Posted on December 13, 2013 by woit

At the Hollywood-style awards ceremony last night for $3 million string theory and biomedical research prizes, it was announced that Yuri Milner and Mark Zuckerberg will now start funding something similar in mathematics, called the Breakthrough Prize in Mathematics. According to the New York Times:

Yuri Milner, the Russian entrepreneur, philanthropist and self-described “failed physicist” who made a splash two years ago when he began handing out lavish cash awards to scientists, announced Thursday that he was expanding the universe of his largess again: This time, he will begin handing out $3 million awards to mathematicians…

For the new math award, Mr. Milner and Mr. Zuckerberg, the co-sponsor of the math prize, will decide who gets the money, in consultation with experts. Mr. Milner declined to say how many mathematicians would be chosen, but there could be quite a number of windfalls in store: for the physics price, there were nine inaugural winners, and for the life sciences prize, there were 11.

I’ve written extensively about the “Fundamental Physics Prize” and what I see as the worst problem with it (heavily rewarding and propping up a failed research program). While many physicists are privately unhappy about this prize and its effects, few prominent ones are willing to speak publicly with their name attached, since this kind of mouthing-off could turn out to be personally extremely expensive. Ian Sample at the Guardian has a story today, which quotes a “prominent physicist who did not wish to be named”:

One prominent physicist who did not wish to be named said the huge sums of money could be used better: “The great philanthropists of the 19th and 20th centuries, like the Rockefellers and the Carnegies, did not create prizes – they created universities and research institutes that have enabled thousands of scientists to make great breakthroughs over the succeeding decades.

“By contrast, giving a prize has a negligible effect on the progress of science. A few already well-recognised people get enriched, but there is little value added in terms of the progress of science compared to the multiplier effect of creating new institutions for scientific research.”

The Guardian does quote one critic by name, but it’s just the usual one.

The physics prize has turned out to be extremely narrowly targeted at one particular subfield of physics, and from what little I know of the life sciences, the prizes in that area seem to be also narrowly targeted (US biomedical research aimed at curing diseases that most afflict those in the developed world). I’m highly ignorant about life sciences research, but it seems striking that the 6 $3 million winners in this field were all men.

I have no idea how Milner and Zuckerberg will go about choosing the $3 million winners in mathematics, and whether this new prize will end up being narrowly targeted to a certain sort of mathematics research. If so, it may have very significant effects on what kinds of mathematics get done. Based on the other prizes, it seems likely that the winners will be mostly prominent US academics, people already well-rewarded by the current academic star system. I don’t see any reason to believe that these kinds of financial awards will allow such mathematicians to do work they wouldn’t otherwise do, so the main argument for the prizes is that the money (and Academy Awards-style ceremonies) will help make them celebrities, and that this is a good thing. One can predict that public criticism from prominent US academics may be rather muted once the checks start coming.

Even if the Milner-Zuckerberg prize does end up focused on the best mathematics research, I still think the whole concept is problematic. The US today is increasingly dominated by a grotesque winner-take-all culture that values wealth and celebrity above all else. While mathematics research, like the rest of academia, has been affected as a star system has become increasingly part of the picture, this field has been somewhat immune to celebrity culture. While people typically think that what mathematicians do is perfectly respectable, they don’t understand much about it and aren’t especially interested. Milner and Zuckerberg want to change this by turning mathematicians into celebrities, but I don’t see any reason to believe this is going to lead to better mathematics.

Update: Here’s the statement from Milner about the planned mathematics prize:

Yuri Milner said: “Einstein said, Pure mathematics is the poetry of logical ideas. It is in this spirit that Mark and myself are announcing a new Breakthrough Prize in Mathematics. The work that the Prize recognizes could be the foundation for genetic engineering, quantum computing or Artificial Intelligence; but above all, for human knowledge itself.”

Posted in Uncategorized | 65 Comments

2014 Milner Prizes

Posted on December 11, 2013 by woit

Last March an Oscar-style ceremony hosted by Morgan Freeman was held in Geneva (see here) to award the 2013 \$3 million Milner Prize to Princeton string theorist Alexander Polyakov. Tomorrow an even more lavish ceremony designed to turn “Oscars of Science” into instant multi-millionaires will be held in Mountain View, California (see here). It will feature Kevin Spacey, Conan O’Brien and Glenn Close, one of whom will presumably award the 2014 $3 million Milner string theory Prize to either Polchinski, Green/Schwarz, or Strominger/Vafa.

If I had to bet I’d go for Polchinski, purely because if they don’t give it to him, that will be two years in a row he walks away with a \$300,000 consolation prize, and having to have him a third time up next year before getting his $3 million would be a bit silly. On the other hand, John Preskill is predicting Green/Schwarz, and he may be right. If you’re going to have a prize devoted to the idea that string theory = fundamental physics since it’s our hope for a TOE, then one really has to give it to Green/Schwarz for originating the whole superstring = TOE business.

On Friday, there will be a day-long symposium at Stanford sponsored by the Milner prize people (see here), with the $3 million man (or men) speaking at 5:30pm, introduced by Lenny Susskind.

Physics will actually be a relatively small part of this awards ceremony, since it will also include the award of six $3 million awards in the Life Sciences. These are being jointly funded by Milner and a group of other prominent internet entrepreneurs.

Update: News is that the awards ceremony will be broadcast by the Science Channel:

Hosted by actor Kevin Spacey, the awards will be presented by the Prize sponsors and by celebrities including Conan O’Brien, Glenn Close, Rob Lowe and Michael C. Hall. The event was produced and directed by Don Mischer, the producer and director of The Academy Awards among other television and live events. The world premiere special 2014 BREAKTHOUGH PRIZES will premiere on Science Channel on Monday, January 27 at 9 PM ET/PT.

According to the press release, Polchinski, Green/Schwarz or Strominger/Vafa will get $3 million for being “psychics”:

The 2014 Breakthrough Prizes are awarded to those who make major breakthroughs and contributions that represent significant advances in our fundamental knowledge of the world. At the ceremony, seven prizes (six for life sciences and one for psychics) of $3 million each will be awarded for a total of $21 million.

Update: As John Preskill predicted, the \$3 million string theory prize went to Green and Schwarz. Polchinski gets a second $300,000 consolation prize and another chance next year.

Update: Vanity Fair covers the event as Hollywood Stars Gather in Silicon Valley for 2014 Breakthrough Prizes in Physics and Life Sciences.

Posted in Uncategorized | 20 Comments

Latest on Amplitudes

Posted on December 10, 2013 by woit

This week the Simons Center is hosting a workshop on “The Geometry and Physics of Scattering Amplitudes”, talks are available here. Last week they (and the YITP) held a one-day symposium on Trees, loops and precision QCD, based around the work of Zvi Bern, Lance Dixon and David Kosower that was recently awarded the 2014 Sakurai Prize. For more about this, see Dixon’s guest post here, or his talk at the symposium.

Bern, Dixon and Kosower started working on amplitudes more than twenty years ago, at a time that it was becoming clear that string theory was not working out as a theory of everything. Calculations in string theory did though lead to interesting new ideas about how to evaluate scattering amplitudes in gauge theory (I see from Dixon’s list of publications that in 1994 he wrote something for the SLAC Beam Line on “Whatever happened to the theory of everything?”, presumably about this, but now too deep in the past to be available on-line). The three Sakurai Prize winners have been steadily working at the problems of amplitudes in gauge theory and quantum gravity, for many years without getting much attention for their work. About ten years ago, things changed when Witten wrote a paper about getting amplitudes from the “twistor string”, a topological string theory in twistor space (the use of twistor space was originated by Penrose back in the late 1960s, and was applied by V.P. Nair to gauge theory amplitudes back in 1988 while he was here at Columbia).

About six years ago Nima Arkani-Hamed entered the subject, where he has had a dramatic effect as an impresario, arguing that this is a route to revolutionary ideas about physics, overthrowing conventional notions of space and time, locality and unitarity, and doing away with the notion that gauge invariance is important. This was partly responsible for his $3 million Milner prize.

For the latest along these lines, a paper with Trnka about “The Amplituhedron” has just appeared, a topic which got wide play in the press earlier this year as Physicists Discover Geometry Underlying Particle Physics, drawing a parody from Scott Aaronson about his own work on the “Unitarihedron” and “Diaperhedron”. Arkani-Hamed’s talk at the Symposium covers both the ideas of Bern, Dixon and Kosower and his recent work with Trnka. It includes many appreciative remarks about their work, including some interesting commentary on how theoretical physics is done. For instance, on the likely reason for people ignoring their early work:

It’s a natural reaction among theoretical physicists, right? At any given time there’s all sorts of interesting things going on, things that other people are doing and things that you are doing and especially if someone else is coming along with something that looks really exciting, in order to justify not dropping everything you have and working on it you have to sort of start inventing these reasons why what they are doing is irrelevant or crap, right? It’s a very human thing, a very human thing, a very natural thing. I think everyone does it to some extent, and really good people eventually will realize that they are fooling themselves and start changing their tune if it’s appropriate. Really bad people, well, we won’t talk about them. It was not at all obvious that this was the tip of a huge iceberg…

There’s also:

Often fields, other fields, have what you might call prophets and there’s I think usually an excessive amount of reverence for these prophets, because the prophets tend to have the property that they say some sort of vague things, I won’t name any names but you can probably figure out the sort of collection of people I’m talking about. They say some sort of vague things about what might happen with physics in the future, and then twenty years later when other people have done all the hard work and really figured out what is going on and how it works in detail and why it works that way and not another way, if it vaguely looks like something they did, they say “see, I said so all along!” They have a fair amount of attraction, I think it’s because a lot of physicists have father-figure issues. But anyway, Zvi and Lance and David were very much not like that, they weren’t just vague prophets saying something was going on, they were extremely specific: there was something going on in this area with these kind of computations in this arena and they knew it. And it took a decade or more for many other people in the field to catch up.

(Personally, I have no idea which “prophets” he’s thinking of.)

Finally, there were some personal comments contrasting Bern, Dixon and Kosower’s low-key style and use of a variety of techniques with his own high-powered hype-driven sales-job of specific ideas to himself and others. Probably a good idea to read this in conjunction with the “Outlook” section of the new paper….

I must say, and I’m really not just saying this to say it, I’m VERY envious of this, because I AM an ideologue. In my defense at least I can say that I’m a serial ideologue, in the sense that I’ll take totally different ideologies and drop the last one without thinking about it, but it’s very important for me personally to be an ideologue when I’m working on something and I think, and I’m saying this in all honesty, the difference is talent. If you’re really good, you don’t have to be an ideologue. You take this, you take that, you’re solving for things left and right, you don’t care where things come from. If you’re not as good, there are 15 million things going on, you’re holding on for dear life in the stiff wind of all the crazy stuff going on in the subject. So you have to have a strong point of view about something, you have to have a strong point of view to sort of pursue a particular direction, otherwise you’ll get beaten around all the time and get nowhere.

So, usually I’ll get up when I talk about scattering amplitudes and give a long introduction about how spacetime is doomed, we have to find some way of thinking about quantum field theory without local evolution in space time and maybe even without a Hilbert space and blah-blah-blah. This is all very high-falutin stuff, this is stuff that Lance wouldn’t be get caught dead saying. I think none of these guys would ever say something that sounds so pretentious, but I have to say it, you know I have to say it, because this is the only way I can get up in the morning, and like “I suck again, OK, here we go, I’m doing it because spacetime is doomed, I swear to God, right”. But, quite seriously, the best people in the subject have this feature, they don’t need to be ideologues, they take the most interesting ideas from every direction they can to make progress, so I really am quite envious.

Posted in Uncategorized | 11 Comments

What’s Next?

Posted on December 9, 2013 by woit

Last week’s public lecture at the Institute for Advanced Study by Nati Seiberg is now available online. He was speaking with the title What’s Next? and promoting a story about where particle physics is and where it is going pretty much identical with that coming from his IAS colleagues. Despite the overwhelming failure of string theory unification and the dramatic evidence from the LHC ruling out popular ideas about SUSY, there was no admission of any discouragement about string theory or SUSY.

String theory was described as the best candidate for a fundamental theory, one that has been making “enormous and exciting progress with amazing new insights” and “all signs are that we will continue to make progress.” For more details Seiberg points to talks given by Witten such as this one. According to Seiberg, string theory has not problems and failures, but “challenges”. One challenge is that “we do not understand the principles” of string theory. Another is that “we need experimental confirmation”, which makes it sound like the problem is one of experiments not done yet, rather than the real problem, which is a “theory” that predicts nothing.

The hierarchy problem is emphasized as the central problem for particle theory, with almost exactly the same point of view as that of Nima Arkani-Hamed, which I’ve discussed here many times (see for example here and here). We’re told not to think of the LHC results as providing evidence against SUSY, but to interpret LHC results as choosing between two possibilities:

  • SUSY exists at LHC scales and arguments about SUSY solving the hierarchy problem are vindicated. Things don’t look good for this so far, but hope is held out for the next run, with an admission that if it doesn’t turn up then, that’s it for SUSY as a solution to this problem.
  • No SUSY at LHC scales just means it is at higher scales, and the multiverse is now brought in to deal with the hierarchy problem. In a recent Science Weekly podcast, Arkani-Hamed says he’s still willing to bet several years salary that SUSY exists, but now he thinks maybe it only shows up at higher energies than he’ll see in his lifetime. He’s willing to bet that SUSY will show up at the next LHC run, but just $50.

Since even enthusiasts who have devoted their career to the cause are now only willing to put up $50 in favor of SUSY at 13 TeV, it’s pretty clear that hardly anyone is now expecting to see this. We’re already in the era of trying to understand the implications of no SUSY at the LHC, with the multiverse the main argument now being deployed in favor of not giving up on cherished speculation about SUSY and strings, no matter what experiments say.

Seiberg does give a different historical analogy for the hierarchy problem, likening it to a fine-tuning problem that Newton was worried about, that of the stability of planetary orbits. Why does a small perturbation of such an orbit not lead to exponentially large changes, destabilizing the orbit? Seiberg lists three possible solutions to such fine-tuning problems:

  • There really is no problem if you understood the theory well-enough.
  • You need to invoke new physics as a stabilizing mechanism.
  • The answer is “environmental”: the orbits are generically unstable, we just happen to live in an unusual place where they are stable.

The odd thing about his use of this historical analogy is that the lesson to be drawn is that of course the answer is the first alternative, but he quickly passes that one by as not worth talking about. I doubt the last alternative ever occured to Newton as anything other than a joke, and don’t know of any evidence that he tried to come up with models of things like new unseen planets to solve this supposed problem. Newton surely realized there was plenty that he didn’t understand about what Newtonian mechanics had to say about celestial mechanics. It’s just as clear that our best model of the Higgs, with its large number of undetermined parameters, is such that we just don’t fully understand where the Higgs potential and Yukawas come from.

The Seiberg talk seems to be one of a series (others listed here) of talks associated with the Milner Fundamental Physics Prize. IAS director Dijkgraaf introduced Seiberg as one of the four IAS winners of the $3 million Milner prize, with this leading his list of honors awarded to Seiberg. The talk was a public one of a sort that has for the IAS not just an educational role, but also a fund-raising one. Something is being sold here, the idea that SUSY and string theory are great successes, with the IAS faculty well-deserving the multi-million-dollar checks awarded to them for their work on these topics. Later this week they’ll be getting together in San Francisco to decide how to split up $3.6 million in new checks among five other string theorists (the announcement of the winner of the 2014 prize will be made Thursday). All of this I fear has something to do with why we’re not hearing from those at the IAS a truer picture of what no SUSY at the LHC means: the collapse of ideas that don’t work and evidence that we don’t yet have any viable conceptual framework for going beyond the Standard Model. This summer the IAS will host its usual PiTP program to train grad students and postdocs in what they need to know to face the future. The topic? String theory.

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