Peter Woit's Blog: Good Stuff, Not Too Hard on String Theory

[marcus]

Peter Woit,

in your "An Evaluation" essay you make a mathematical comparison
between the Standard Model (where "two of the most important concepts... are that of a gauge field and that of the Dirac operator") and String theory
where those two concepts are "not fundamental, but are artifacts of the low energy limit".

You say:
"The Standard Model is dramatically more 'elegant' and 'beautiful' than string theory in that its crucial concepts are among the deepest and most powerful in modern mathematics."

this is something which as a non-expert with however some mathematical experience I would like to get in clearer focus. Maybe you have a alternative line of development in mind which does embody the strengths of 20th c mathematics in a more fundamental way.

It sounds as if particle physicists may have dragged things off into some place where they feel happy with the mathematics but which is not the direction theoretical physics is ultimately going to go and not, ultimately, in their own best interest. this is just a vague suspicion. sorry if too vague.

 

[notevenwrong]

Haelfix raised the issue of what is your "main beef" and got me curious.
He suggested it was lopsided funding. I want to try to get the essential
points isolated and in focus, at least for me. I don't hear a complaint (which is I guess what a beef is) and maybe I hear more a warning and a demand for integrity. Have to reflect a bit.

I think you've got it right. My point of view is that the over-hyping of string theory has lead to a really unhealthy situation in particle theory, and the remedy for this is for people to start honestly evaluating the results of the last 20 years work on the subject. I think if they do that they'll conclude that the idea of unifying the standard model and gravity in a 10/11 dimensional supersymmetric string/M-theory simply doesn't work. Once they get used to that idea, maybe people will start thinking about other more promising things.

 

[notevenwrong]

Maybe you have a alternative line of development in mind which does embody the strengths of 20th c mathematics in a more fundamental way.

It sounds as if particle physicists may have dragged things off into some place where they feel happy with the mathematics but which is not the direction theoretical physics is ultimately going to go and not, ultimately, in their own best interest. this is just a vague suspicion. sorry if too vague.

I tried to explain the alternative line of development I have in mind in
hep-th/0206135
That paper also refers to an old paper of mine in Nucl. Phys. B., which explains an idea about the relation of space-time geometry to the standard model.

This stuff is all very vague at this point, I certainly don't have a well-understood way of implementing many of the ideas that seem promising to me. This is all just as "Not Even Wrong" as string theory, maybe more so. But I think it's at least mathematically more attractive. If good mathematics leads to good physics, this may go somewhere.

 

[jeff]

As far as I can tell, most people have lost interest in it [the IKKT model]. When that happens there's generally a good reason.[/B]

This together with it's converse, that an ideas dominance speaks well of it's promise, makes your position more difficult to defend. Keep in mind that theory selection in an exact science like physics is very different than in the social sciences in which subjective opinion necessarily plays a much larger role.

 

[Urs]

As far as I can see research on Matrix Models is hampered by the fact that it is - difficult! :-)

When you hear the Potsdam group, Nicolai et al., speak about their reserach in supermembrane/BFSS model, you'll note that they will tell you that after fascinating results to lowest order (graviton scattering described by a simple matrix model, just imagine! :-) progress to higher orders is becoming really difficult, computationally.

The same seems to be true for the IKKT model. They have apparently run numerical computer programs for quite a while to see if they can approximately compute aspects of the exact solution, but they would need much more computation power to do that. I'll look up the links for you.

 

[Urs]

Here are some links to papers that discuss attempts to derive non-perturbative phenomonology (like 4-d spacetime) from stringy matrix models:

http://golem.ph.utexas.edu/string/archives/000314.html#c000863

 

[marcus]

I tried to explain the alternative line of development I have in mind in
hep-th/0206135
That paper also refers to an old paper of mine in Nucl. Phys. B., which explains an idea about the relation of space-time geometry to the standard model.

"Quantum Field Theory and Representation Theory: a Sketch"
http://arxiv.org/hep-th/0206135

I downloaded this paper to see whether it was entirely inaccessible to me or whether I could catch some of the drift of the conclusions...

Focusing momentarily on a part of the conclusions:
-------exerpt from "QFT and Representation Theory: a Sketch"----

While the difficulties one runs into in trying to quantize gravity in the standard way are well-known, there is certainly nothing like a no-go theorem indicating that it is impossible to find a quantum field theory that has a sensible short distance limit and whose effective action for the metric degrees of freedom is dominated by the Einstein action in the low energy limit. Since the advent of string theory, there has been relatively little work on this problem, partly because it is unclear what the use would be of a consistent quantum field theory of gravity that treats the gravitational degrees of freedom in a completely independent way from the standard model degrees of freedom.

One motivation for the ideas discussed here is that they may show how to think of the standard model gauge symmetries and the geometry of space-time within one geometrical framework.

Besides string theory, the other part of the standard orthodoxy of the last two decades has been the concept of a supersymmetric quantum field theory. Such theories have the huge virtue with respect to string theory of being relatively well-defined and capable of making some predictions. The problem is that their most characteristic predictions are in violent disagreement with experiment. Not a single experimentally observed particle shows any evidence of the existence of its 'superpartner'...

----end of quote----

edit: remove inessential comment

 

[selfAdjoint]

Breaking news! Peter Woit has important news for this glorious first of April.

 

[pelastration]

Breaking news! Peter Woit has important news for this glorious first of April.

... isn't this ... what I told you DickT? There was no concept.
But www.superstringtheory.com should be active again in some hours. ;-)

 

[pelastration]

But www.superstringtheory.com should be active again in some hours. ;-)

So, in my time it's now April 2.
Peter Woit made a great joke.
But seriously, the forum of www.superstringtheory.com should be active again today ... or on April 3? . That's what Patricia promised. Let's see if here server works.

 

[marcus]

Breaking news! Peter Woit has important news for this glorious first of April.

About time!


BTW I see Physics Forums got a mention in Woits blog

 

[jeff]

So, medical school or law school: Which type of janitorial position should I go for?

 

[selfAdjoint]

Look at it this way: At least you weren't outsourced!

 

[eforgy]

April Fools!

Peter must be getting a good chuckle out of this thread (if he's aware of its existence) :)

 

[lethe]

Peter must be getting a good chuckle out of this thread (if he's aware of its existence) :)

he is definitely aware of it. he posted to it.

 

[eforgy]

Oops!

Oh well. That is less fun then :)

I read the first post by selfAdjoint (without noting the earlier March date) pointing to the weblog, but I did so just yesterday so the first entry I saw there was his April 1 entry. I assumed this whole thread represented a duping by him on us all :)

In any case, I thought it was fun. Thanks Peter! :)

More seriously, I totally agree with the charge that string theory is over hyped. In fact, I personally think theoretical physics as a whole has been headed in the wrong direction since the (in?)famous Einstein/Bohr debates. If I could go back in time and witness any event (series of events actually) in history, it would most definitely be the Einstein/Bohr debates. I would go even as far to say that one of the reasons theoretical physics has made as little progress as it has in the last 50+ years is due to not taking Einstein's later arguments more seriously.


Eric

 

[marcus]

I would go even as far to say that one of the reasons theoretical physics has made as little progress as it has in the last 50+ years is due to not taking Einstein's later arguments more seriously.


Eric

please expand
(might eventually need a separate thread since outside topic of Woit's blog)

 

[jeff]

I...agree...that string theory is over hyped.

This isn't a simple case of stupidly putting all our eggs in one basket. Strings is the only quantum gravity theory we know of, and we only found it by accident. It's an enormously deep theory rich in ideas that we don't yet understand, but that have produced new and powerful perspectives on what is already known, and serve as points of departure for the discovery of new physics that could end up leading us away from strings as well as any other idea. In other words, strings is not in any sense a stagnant research program. String theorists don't deny the basic merit in warnings against creating an environment unfriendly to nonstringy ideas, but they really do feel that given what we understand about strings and our previous failures to quantize gravity, the current concentration of effort on it, though troubling to some and worth discussing, is justified. It's also a lot of fun.

 

[eforgy]

In other words, strings is not in any sense a stagnant research program. String theorists don't deny the basic merit in warnings against creating an environment unfriendly to nonstringy ideas, but they really do feel that given what we understand about strings and our previous failures to quantize gravity, the current concentration of effort on it, though troubling to some and worth discussing, is justified. It's also a lot of fun.

I agree 100% and I think from what I've read that Peter would agree too. The point is, as Peter more eloquently stated, that things seem to have gotten to the point where research in nonstringy ideas is discouraged (at least indirectly by lack of funding opportunities). That is sad.

I'm attracted enough by what string theory has to offer that I am presently trying to learn some of the basics myself (as you can probably tell by skimming the String Coffee Table). However, I certainly don't think string theory (in its present form) is the right theory, although it may (just as LQG may) help foster ideas in the right direction. In this regard, it is definitely worth learning.

Eric

 

[marcus]

...In any case, I thought it was fun. Thanks Peter! :)

More seriously, I totally agree with the charge that string theory is over hyped. In fact, I personally think theoretical physics as a whole has been headed in the wrong direction since the (in?)famous Einstein/Bohr debates. If I could go back in time and witness any event (series of events actually) in history, it would most definitely be the Einstein/Bohr debates. I would go even as far to say that one of the reasons theoretical physics has made as little progress as it has in the last 50+ years is due to not taking Einstein's later arguments more seriously.


Eric

I wish you would explain the historical perspective more clearly. I had the impression that it is only in the last 20+ years that progress in theoretical physics fails to get regular verification and guidance from experiment.

I had the impression that from the Fifties until at least 1980 there was a kind of triumphant march of theory with experiment hand in hand (excuse the metaphor :) if possible) where theoreticians would predict something and then in a matter of months the people at the accelerator would find it.

Do you mean this could have been better if the theoreticians had taken to heart the later sayings of Einstein? It is an intriguing idea and may have an important germ of truth as afterthoughts sometimes do have. But I do not see how and wish for some clarification.

 

[sol2]

From a laymen's perspective, the second revolution has already happened. Just to point out where this has lead too. M Theory

Imagine now then, developing perspective in regards to Warp Drive, from a brane scenario?

Most certainly there is a architectual apparatus that is mathematically driven, but like understanding gravitational waves, the graviton helps us to recognize the dimensional perspective of the bulk? Do we then dismiss this new perspective?

I am open to corrections

 

[marcus]

reconnecting with topic---Haelfix' focus on "main beef"

Before April 1 ( chuckling over the spoof in the blog) we were discussing
Woit's criticism of excess hype and unbalanced funding.
notevenwrong responded to this:

Haelfix raised the issue of what is your "main beef" and got me curious.
He suggested it was lopsided funding. I want to try to get the essential
points isolated and in focus, at least for me. I don't hear a complaint (which is I guess what a beef is) and maybe I hear more a warning and a demand for integrity. Have to reflect a bit.

I think you've got it right. My point of view is that the over-hyping of string theory has lead to a really unhealthy situation in particle theory, and the remedy for this is for people to start honestly evaluating the results of the last 20 years work on the subject. I think if they do that they'll conclude that the idea of unifying the standard model and gravity in a 10/11 dimensional supersymmetric string/M-theory simply doesn't work. Once they get used to that idea, maybe people will start thinking about other more promising things.

 

[selfAdjoint]

I've been rereading Kaku's Hyperspace (thought I ought to) and I was struck by the way he described the enthusiasm and hope of the physicists who developed 10 dimensional supergravity in the 1980s. They thought for a while they had IT, the theory of everything. But it turned out to be unrenormalizable. Just wrong.

Superstrings, and string physics generally, has never sent this signal. One of the first things proven in it was that it didn't require renormalization, because the worldsheets didn't intersect in points, as world lines of particles did. So the situation is not quite "not even wrong", because the failure of the "wrong" signal to appear is not due to the weakness of the theory but to its strength.

Because they never have had the theory itself tell them it was hopeless, string physicists have never given up hope. They have gone farther and farther, and how ever far it is, the math tells them it's OK to press on. I can't help but feel that some of the string physicists are wandering in the wilderness, but their stuff is still mathematically sound, so how can you tell? At least one of the posters on the new string board feels the huge landscape of vacua is amenable to calculation and not that big a threat. More power to him.

 

[marcus]

... At least one of the posters on the new string board feels the huge landscape of vacua is amenable to calculation and not that big a threat. More power to him.

sA it was a real delight that you tuned us into Woit's blog! I check it every 5 or 6 days or so. notevenwrong has commended the new board and commented just yesterday on what I imagine are the same posts you are referring to here. His comment is "pass the popcorn!"

http://www.math.columbia.edu/~woit/blog/

--------exerpt from "Not Even Wrong" blog-----
April 07, 2004
KKLT Smackdown
I was dubious of the value of a new "sci.physics.strings" newsgroup when it was first proposed, but now must admit it seems to have been a great idea It started up a week or two ago, and quickly someone asked the seemingly innocuous question of how many different possible vacuum states were expected in string theory. This is a hugely controversial issue among string theorists, largely because recent evidence is that the number is definitely astronomically large, and this makes it very unlikely that current ideas about string theory can ever be used to predict anything about the real world.

A lot of the discussion revolves around the "KKLT" proposal for constructing a large number of these vacuum states. The acronym is the initials of the authors, three of whom are at Stanford: Shamit Kachru, Renata Kallosh and Andrei Linde. Also at Stanford is Lenny Susskind, who has been spending the last year or so going around giving talks on the "Landscape of String Theory". It's hard to believe this, but Susskind's claim is essentially that the lack of predictivity of string theory is a good thing, since it allows so many possibilities that anything can happen. One can then invoke the "Anthropic Principle" to explain why the world is the way it is. It seems that Susskind is even writing a book about this wonderful "discovery".

Amazingly enough, the thread about this on sci.physics.strings, entitled "Conceptual question", has brought a public attack on the "Stanford propaganda machine" by a well-known European string theorist (Wolfgang Lerche), a detailed defense of his ideas by one of the KKLT authors (Kachru), contributions from the inimitable Lubos Motl from Harvard, and, while I was writing this, a defense of the anthropic principle from Joe Polchinski just appeared, which attacks the "cult of monovacuism" embodied by David Gross and Ed Witten.

Thanks are due to the creators of this newsgroup. Pass the popcorn!

-----------end quote-------------

sA you know I very much like the woity style of writing and
fully concur with his assessment that Lubos Motl is inimitable
and moreover I detect within myself distinct leanings towards monovacuism
woit IS the popcorn in this movie

 

[selfAdjoint]

Well, I find Woit kind of a guilty pleasure. It bugs me that the whole discussion is so snarky - I don't see how any of that will affect the outcome one way or another. And I am perfectly willing to get slammed by both sides because I won't play party politics with the future of physics.

Physics is a gift physicists give to humanity. The hard work of creating that gift is a high calling. To play the schoolyard squabbler in the middle of that is very sad to see.

 

[marcus]

... And I am perfectly willing to get slammed by both sides because I won't play party politics with the future of physics.

I agree. The way your interests and intuitions differ from mine (as well as coincide) are like a compass needle to me.
the diversity of honest views from intelligent people is just about the most valuable thing this kind of situation offers

We probably both deplore mafia-like activity or slamming or self-righteous bullying.

Simple squabbling I don't mind. Scholars (Newton/Leibniz) have traditionally conducted squabbles of epic proportion. We small fry may continue the custom without too much embarrassment. Maybe it is a form of mass entertainment. I expect to be permitted to express my leanings---interest in A and non-interest in B---and give reasons without being attacked. I don't object when other people express different interests and give reasons, although I may occasionally disagree.

I also do not object to satire. Sometimes admonishment doesn't work. Mafia-like activity, bullying, thought-policing, slamming people who don't toe the line or belong to the correct "camp" may persist despite moral objection. If someone resorts to satire (whether a big guy like Moliere or a little guy like Peter Woit) I am delighted. It's a literary pleasure that I'm not going to feel guilty for enjoying!

For some reason EB White's book about a mouse called Stuart Little comes to mind. when the mouse taught school there was only one rule (dont be mean) did you ever read that to your kid(s)?

 

[jeff]

What are your feelings on trying for sci.phys.lqg?

 

[marcus]

What are your feelings on trying for sci.phys.lqg?

that is a pleasant question to consider
thanks for asking it, hope some folks will reply
(I can't right now because have to go out on Easter errands)

 

[chroot]

jeff,

You mean, in trying to get such a group created?

- Warren

 

[jeff]

jeff,

You mean, in trying to get such a group created?

- Warren

Yes! Peter woit commented to the effect that he now likes the idea of sps since it's already reflecting the kind of decension among string theorists that characterize his own views. However, the decension on these issues has always been quite open. But I've never seen the same kind of open decension among members of the lqg camp. Maybe they all agree that getting lqg to work is just an unimportant technicality? Anyway, extablishing sci.phys.lqg probably isn't all that realistic.