Not Even Wrong

Slides from the talks at Strings 2006 are now available. I’ve spent a little while looking through them today, and am sorry I don’t have time to say much about them. Lots of more or less the same thing as in earlier years, and many talks devoted to complicated arguments designed to, as Eva Silverstein writes, populate, probe or constrain the Landscape. Nothing remotely like a plausible idea about how to ever get a prediction of anything out of this, but also virtually no anthropic arguments. I assume this was due to the iron fist of organizer David Gross.

I was pleasantly surprised to see that there were quite a few mathematically very interesting talks. Besides many talks of the sort that have been common in recent years dealing with the topological string, there were several that had nothing to do with string theory, but involved interesting mathematics related to QFT, and many of these had to do with work Witten is involved with, so they may get some attention. These were:

1. Witten’s own talk on Gauge Theory And The Geometric Langlands Program.

2. Kapustin’ talk on the same topic, entitled Topological reduction of supersymmetric gauge theories and S-duality.

3. Gukov’s talk on Surface Operators in Gauge Theory and Categorification, where he mentions that some of what he discusses is based on on-going joint work with Witten.

4. Nikita Nekrasov’s talk on Beyond Morse Theory.

So, as far as physics goes, the organizers are not allowing any talks on alternatives to string theory (the only mention of LQG seems to have been Dijkgraaf’s making fun of it), but they are willing to allow mathematical talks on QFT that are not related to string theory, especially since this is the field that Witten seems to be doing a lot of work in.

A couple people wrote in this morning to tell me about today’s Doonesbury, which features slacker Zipper Harris (who has a blog) trying to impress a woman he last saw in sophomore year of college. He’s still undecided about his major, but tells her:

I’m thinking physics.  Yarn theory.

The Economist has an article this week entitled To catch a gravitational wave. It’s about the proposed LISA satellite experiment designed to measure gravitational waves, with a much greater sensitivity than LIGO. According to the article, what would you guess is one of the main goals of the LISA experiment? Exactly, like most other ambitious experiments, it will solve the problem of how to test string theory:

[LISA] could allow scientists to examine the validity of string theory, which says that there are more than four dimensions to space-time and that the extra dimensions are hidden. String theory has come under fire because its predictions have so far proved untestable. The normal version has it that these dimensions are curled up in strings that are smaller than the known elementary particles. However, in some versions strings form very long “superstrings” that stretch across the universe. These superstrings form loops and vibrate, radiating gravitational waves; they can also crack like whips, sending bursts of gravitational waves towards Earth. “Seeing direct evidence of strings would be as important as discovering that the world is made of atoms,” claims Craig Hogan, an astronomer at the University of Washington, who is a member of the international science team for LISA.

The writer appears to be a bit confused about what a superstring is, guessing that it is a really big string (a cosmic string). This is presumably all based on the idea promoted by Joe Polchinski that it is in principle possible to come up with superstring theory models with cosmic scale superstrings, whose effects would be visible through gravitational lensing and gravitational waves. As far as I can tell, this is just another case of the phenomenon that one can get pretty much anything one wants out of string theory, and there’s no reason at all to expect cosmic strings with just the right properties to have been invisible so far, but visible through gravitational wave effects measurable by LIGO or LISA.

Two years ago there was a press release about this from UCSB quoting Polchinski as saying

the gravitational signatures from cosmic strings are remarkable because they are potentially visible even from the early stages of LIGO! That means ‘potentially visible’ over the next year or two.

LIGO hasn’t seen anything, so time was up for this nearly two weeks ago but I haven’t noticed any UCSB press releases reporting that things haven’t worked out.

There was some excitement a year or so ago when a group claimed that an astronomical object might be a single galaxy lensed by a cosmic string. Turned out to just be a pair of nearby galaxies.

LISA is tentatively scheduled for launch nearly ten years from now, so it will be a while before this particular “test of string theory” brings in any results. This past week the 6th Annual International LISA Symposium was held in Maryland.

JoAnne Hewett at Cosmic Variance reports that the latest LHC commissioning plan will not involve collisions at 14 TeV until 2008, with earliest physics run in April 2008. First collisions will be in November 2007, but at Tevatron energies. Until recently the plan had been to try for first collisions at full energy next summer, and some had hoped that a bit of new physics data could be acquired in 2007, but it looks like that is not to be. For a summary talk on the situation, see here.

Burton Richter’s talk at the panel on “Naturalness” at SUSY06 is now on-line. Richter blasted his three theoretical colleagues on the panel (two of whom are his colleagues at Stanford) in forceful terms as no longer doing science:

… I think some of what passes for the most advanced theory these days is not really science.

I see no problem if part of the theory community goes off into a kind of metaphysical wonderland, but I worry that they may be leading too many of the young theorists along into the same wonderland. Simply put, it looks to me as if much of what passes as the most advanced theory these days is more theological speculation that it is the development of practical knowledge.

… the distinction between theory as theological speculation and as the development of practical knowledge. Theological speculation is the development of models with no testable consequences.

[About supersymmetry and naturalness] The price of this invention is 124 new constants which I always thought to be to high a price to pay.

Naturalness may be a reasonable starting point to solve a problem, but it doesn’t work all the time and one should not force excessive complications in its name.

The Anthropic Principle is an observation, not an explanation…. I have a very hard time accepting the fact that some of our distinguished theorists do not understand the difference between observation and explanation, but it seems to be so.

… what we have is a large number of very good people trying to make something more than philosophy out of string theory. Some, perhaps most, of the the attempts do not contribute even if they are formally correct.

It is not that the landscape model is necessarily wrong, but rather if a huge number of universes with different properties are possible and are also probable, the landscape can make no real contribution other than a philosophic one. That is Meta-physics, not physics.

After all, the Hebrews after the escape from Egypt wandered in the desert for 40 years before finding the Promised Land. It is only a bit more than 30 since the solidification of the Standard Model.

Update: Clifford Johnson was there, and has a report on the session. He describes Richter’s talk as “It was basically a loud fart in a quiet cathedral, during evensong. Excellent.”

The anthropic string theory landscape seems to be having ever greater success in taking over fundamental physics and turning it into pseudo-science. It’s being promoted by no less than 2008 presidential candidate Wesley Clark, the following is from a transcript of his remarks to science bloggers at a blogger convention in Las Vegas:

Read Leonard Suskind’s new book, called “The Cosmic-” It’s called “The Cosmic Landscape And Intelligent Design” if you want to see something that’s overpowering. Suskind is the inventor of cosmic string theory, and what he does is he takes cosmic- he takes the idea of the universe. He says the universe is- see, what’s happening in intelligent design is people are saying, ‘Ah well, you see, the, the, the wavelength of, of, of the electron and Planck’s Constant and all these numbers are so odd. They don’t- they’re not even numbers, you know. They, they, they don’t balance each other. It’s sort of 1.- It’s like the figure of pi, 3.14159… Why would it be such an odd number? Why, why wouldn’t god make the universe, you know, symmetrical?’

(laughter)

Then they said, ‘well, because, you know, it’s like there’s only one on 10 to the 50th chance that the universe could have worked out in a way that mankind could survive. Therefore, you know, this must have been an intelligent designer who created this universe especially for us.’ What Suskind does is he turns it on its head. He says, “You know, if you look at string theory and the 9+1 dimensions” or 10+1 dimensions, and I’m not sure how he knows that time only has one dimension, but he does. (inaudible) would say I’m very arrogant for questions questioning this.

(laughter)

But what Suskind does is he turns it upside down. He says, “Look there are- there is an infinite number of universes.” He calls it a multiverse, and he says that however the motive forces, and nobody understands why quarks pop in and out of existence. Nobody understands it, but apparently they do. And apparently there are many, many universes, and we’re here in this one. And maybe there are others in which Planck’s Constant has a different number, in which the speed of light is not 186,200 miles per second. Who knows? We don’t know.

Commenter Patrick wrote into point out a review article on this from graduate student Joseph Conlon, published in the latest issue of Contemporary Physics (not available on the arXiv or anywhere else for free as far as I can tell). It’s entitled, “The string theory landscape: a tale of two hydras”, with the first hydra the non-renormalizability of gravity (supposedly slain by string theory), the second the prolifieration of vacuum states. Conlon seems to think that the fact that string theory can’t ever be used to predict anything is not a serious problem:

We started with a dream of a unique string theory compactification reproducing the structure of the Standard Model. This is a dream apparently shattered by the existence of the landscape. Granting the landscape and its existence, does this mean string theory is inherently unpredictive at low energies? If this is true, this is sad but no disaster. Quantum field theory, of itself, is also unpredictive.

I’ve written elsewhere about why this analogy with QFT doesn’t hold, but on the face of it there’s obviously something wrong, since we use QFT all the time to make detailed, testable predictions about the real world, something that string theory, according to Conlon, will never be able to do.

Talks from the plenary section on “naturalness” at SUSY 06 are online. The usual advertising job from Susskind and Linde, the one that seems to have impressed Wesley Clark. Wilczek gives a more substantive talk, and seems to have some interesting new speculative ideas about models near the end.

On another topic, I’ve been wondering what the current state of peer-review of hep-th papers is. Personally I think it has been several years since I’ve looked at any of the main journals that publish papers in this area, and I suspect this is true of many people these days. The Bogdanov affair several years ago showed that refereeing in this area had become pretty much a joke, with the brothers having no trouble finding five journals willing to accept utter nonsense.

Looking at the arXiv and SPIRES listings, which seem to contain publication information after submitted papers have been accepted, many papers (e.g. Susskind’s single-authored papers on the landscape), don’t seem to ever have been peer-reviewed and published. I’m curious what people think of this. How many hep-th authors have stopped submitting their papers for refereeing? Is the data on the arXiv and SPIRES an accurate reflection of this? Does the fact that an author’s preprints don’t have publication data for the last few years mean they weren’t submitted for refereeing, or could this be due to time lag in refereeing/publication, or incompleteness of the data?

Update: Courtesy of Google, there’s now an on-line talk by Washington Taylor promoting the Landscape to people working for the company. He gives the number of vacua as at least 10¹⁰⁰⁰. The number of well-known physicists out there promoting this nonsense to the general public is amazing (via Lubos).

Since many people have been posting off-topic comments here that were censored over at Lubos Motl’s Reference Frame, I’m creating a separate posting so that there will be an appropriate place for these. Also, if you want to try and carry on a discussion with Lubos on the topics of these comments, here is the place to try (although I don’t quite know why you’re bothering…).