I didn’t have much luck when I tried here to find out exactly what had happened at the panel discussion in Toronto at Strings 2005 last month. One graduate student (Florian Greimer) commented on Jacques Distler’s weblog that he felt quite depressed after listening to it, earning a slap-down from Jacques, who evidently found it so upsetting that he got up and left halfway through it, and later wrote about why such discussions were a waste of time.
Today’s New York Times has a report on the panel discussion by Dennis Overbye entitled “Lacking Hard Data, Theorists Try Democracy”, which makes it clear why many of the people in attendance were depressed and/or upset. The title of the piece refers to the previously reported fact that the audience voted overwhelmingly against the idea that the anthropic principle was what explains the value of the cosmological constant. What I hadn’t heard before is that the panel itself, representing the leadership of the field, voted rather differently, splitting evenly (4 to 4, with abstentions) over the issue. It looks like Susskind’s point of view has gone from being a minority one among leading string theorists to one that half of them are willing to publicly sign on to. I can see why the audience was depressed. Overbye reports the reaction to the audience vote as “‘Wow’, exhaled one of the panel members, amid other exclamations too colorful to print here.”
The article also includes some truly bizarre and delusional quotes, which it is hard to believe were not taken out of context. Michael Douglas is reported as saying that “We’ve done very well for the last 20 years without any experimental input”, which is just so weird I don’t know what to say about it. Andy Strominger deplored the increasing pessimism about string theory, trying to rally the faithful with the promise of glory in the after-life: “Sooner or later we will get there, and when we do we’ll all be heroes.”
Susskind gave his vision of the immediate future of the field: “there’s nothing to do but just hope the Bush administration will keep paying us”, and Amanda Peet has stolen one of my favorite lines, saying that string theory should be trying to get government funding as a “faith-based initiative”.
So Peter, what are we supposed to do, completely forget about quantum gravity? Don’t you agree, that physical scenarios where both quantum theory and gravity matter likely involve Planck scale energies and are thus out of reach for a very long time?
The loopy people claim they make predictions that are mostly about violating relativistic dispersion relations for high energy gamma rays. Do you believe those? I cannot make up my mind if those predictions are just due to a 3+1 split that breaks Lorentz invariance.
‘Andy Strominger deplored the increasing pessimism about string theory, trying to rally the faithful with the promise of glory in the after-life: “Sooner or later we will get there, and when we do we’ll all be heroes.â€?’
Ha! Suicide theorists! Sacrifice yourself and there will be 71 Nobel prizes awaiting you in paradise!
Hi Robert,
First of all, I don’t think there is any one thing that people should be doing, they should be trying a lot of different things. The big problem of the last 20 years is that almost all of the effort in the field has gone into one very speculative idea about quantum gravity.
As for other things to try, if you want to just think about how to quantize gravity, you are kind of stuck without having experiment to help you. In that case all you have to go by is mathematical consistency and elegance, and you need to behave a lot more like a mathematician. By this I mean you need to be very clear about exactly what your theory is, what you understand about it, and what you don’t understand. You can’t get away with just sweeping problems under the rug the way you can when there are experiments around that tell you whether you’re on the right track or not. You shouldn’t go around claiming you have a “consistent theory of quantum gravity” when you don’t, e.g. when all you have is a divergent series that you hope is asymptotic to some unknown, but consistent theory.
I’ve always personally felt that the real question is not how to quantize gravity, but how to quantize gravity in some way that tells us how the geometry of space-time is related to the geometry of the standard model. It would be disappointing if these two things have nothing to do with each other, and the danger is that there may be lots of ways of “quantizing gravity”, and with no connection to experiment you could never choose amongst them. String theory became so popular partly because it held out hope for being able to put the standard model and gravity into the same structure. But there’s no reason to believe it’s the only way of doing that, and people should be trying different things in order to come up with some new ideas.
“Theoretical calculations suggest it should be 1060 times larger than what astronomers have measured. ”
Wow, they’ve gotten the discrepency down to three orders of magnitude? That’s pretty good.
YA GOT TROUBLE
Well, ya got trouble, my friend.
Right here, I say trouble right here in Jersey City
Why, sure, I’m a stringy player
Certainly mighty proud to say,
I’m always mighty proud to say it
I consider the hours I spend pulling out all my hair are golden
Help you cultivate horse sense and a cool head and a keen eye
Now, folks, let me show you what I mean
You’ve got one, two, infinitely many stringy vaccua
Vaccua that mark the difference between a gentleman and a bum
With a capital ‘B’ and that rhymes with ‘Stree’ and that stands for ‘String’
And all week long, your Jersey City youth’ll be fritterin’ away
I say, your young men’ll be fritterin’
Fritterin’ away their noontime, suppertime, choretime, too
Ya got trouble, folks, right here in Jersey City
with a capital ‘T’ and that rhymes with ‘Stree’
and that stands for ‘String’
May I have your attention, please? Attention, please
I can deal with this trouble, friends,
with the wave of my hand, this very hand
Please observe me, if you will I’m Professor Harold Hill
and I’m here to organize a quantum computer band
Oh think, my friends, how can any stringy guess
ever hope to compete with a gold Q comp
Rah, rah, rah-da-da-da-da, rah-rah
Remember, my friends, what a handful of Apple players
did to the famous, fabled walls of I B M
Oh, corporation walls come a-tumblin’ down
Oh, a band’ll do it, my friends, oh yes
I said a Q C band, do you hear me?
I say Jersey City’s gotta have a Q C band
and I mean she needs it today
Well, Professor Harold Hill’s on hand
and Jersey City’s gonna have her Q C band
Just as sure as the Lord made little green apples
and that band’s gonna be in uniform
Peter, in reply to Robert’s question
“… So Peter, what are we supposed to do … ? “,
you said
“… I don’t think there is any one thing that people should be doing, they should be trying a lot of different things. … people should be trying different things in order to come up with some new ideas. …”.
With respect to “different things”, some commonly mentioned such as LQG and Dynamical Triangulation do have some institutional support, although nowhere near as much as conventional superstring theory, so they are actually in the process of being evaluated by the physics community.
Others such as the models of Quantoken, Matti Pitkanen, Jack Sarfatti, and others, and my model, are (afaik) pretty much individual works with little or no institutional support, and may be regarded by many as crackpot.
Even if some of the individual works contain crackpot elements, it may be that other elements of those individual works might contain seminal insights that might, with further development, grow into a useful unification of gravity and the standard model.
Therefore, my proposal would be that a chunk of superstring money and manpower should be diverted from the abyss of the landscape/swamp and used to do detailed evaluation of all aspects of the individual models. My guess is that even if none of the individual models were totally free of flaws, there would be enough germs of truth that the evaluators would come up with at least one, or maybe more, serious alternative candidates for realistic unification of gravity and the standard model.
My proposal would require agreement of the powers-that-be in physics that any grad student or postdoc doing evaluative work should get credit for work done in evaluating, no matter how many or few (if any) positive results emerge.
Politically, I feel that my proposal is unlikely to be implemented, but I feel that the alternative is to watch fundamental physics sink into the quicksand of the landscape/swamp and remain for the forseeable future in a New Dark Age.
Tony Smith
http://www.valdostamuseum.org/hamsmith/
the report said the panel split 4 to 4 with abstentions, but the panel was advertised as consisting of these 8 people (plus the moderator Shenker):
Raphael Bousso
Shamit Kachru
Ashok Sen
Juan Maldacena
Andrew Strominger
Joseph Polchinski
Eva Silverstein
Nathan Seiberg
maybe they added more people to the panel at the last minute, but if it was just those 8, plus Shenker, it doesnt quite add up to have 4+4 + abstentions.
My guess is that they foresaw that issue coming to the fore and they handpick BALANCED the panel on that issue. So automatically they got a 4+4 vote. the only thing meaningful, or not prior arranged, was the unbalanced way the audience voted.
I think one can pretty accurately guess who voted how:
Pro-Landscape:
Bousso, Polchinski, Kachru, Silverstein (note, all from West Coast)
Anti-Landscape:
Maldacena, Seiberg, Sen, Strominger (not from West Coast)
noncommittal: Shenker
Maybe there were one or two other people there not listed (Douglas and Witten are quoted in the article), but I’d bet this division is more or less right.
I doubt the panel was chosen specifically to balance landscape/anti-landscape, but since the topic was the future of the field, I’d guess an attempt was made to choose younger people
working on the latest, hottest topics (I think just about everyone on the panel is under 50, or at most, barely over it). For better or worse, the landscape is the one new idea in the field (the KKLT paper is the only recent one with a large number of citations), so that’s probably why the landscape side of the argument was well represented.
Douglas and Witten were both in the audience. I don’t remember anyone else on the panel off the top of my head. Somehow, I seem to remember Juan being the fourth anthropic vote, but I very well could be wrong.
Robert,
Nobody expects you to care about Peter’s opinion any more than Smolin cares about what you and Policastro write.
Nevertheless, if you seriously want an advice, mine would be to get rid of some excess baggage. The dominant ideology dictates that every gauge anomaly is inconsistent. Of course, we know where this prejudice comes from: the chiral anomaly in Yang-Mills theories leads to unitarity violation and it is indeed inconsistent. Alas, to generalize this result to rule out every gauge anomaly is manifestly wrong; it is clearly stated in GSW that the free subcritical string is consistent, despite its conformal gauge anomaly. Incidentally, it is funny to see how Lubos wriggles when I point out this well-known fact. Last time he started to babble about flux compactifications and Eva Silverstein, as if either had anything to do with the no-ghost theorem.
Do with this whatever you like. But to believe that every gauge anomaly must lead to an inconsistent theory is manifestly false, and I don’t see how a manifestly false prejudice could be a good guiding principle.
Think the numbers in the NYT article should be 10^500 and 10^60 right?
//Ingemar
I note that Joe Polchinski voiced one of my favorite theses: That the third string revolution has already happened and it was anthropic.
“Others such as the models of Quantoken, Matti Pitkanen, Jack Sarfatti, and others, and my model, are (afaik) pretty much individual works with little or no institutional support, and may be regarded by many as crackpot.
“Even if some of the individual works contain crackpot elements, it may be that other elements of those individual works might contain seminal insights that might, with further development, grow into a useful unification of gravity and the standard model.
“Therefore, my proposal would be that a chunk of superstring money and manpower should be diverted from the abyss of the landscape/swamp and used to do detailed evaluation of all aspects of the individual models.” Tony Smith
Tony, this is not going to happen even over the dead bodies of string theorists. What will happen when string theory sinks will be a reversion to the situation of the late 19th and early 20th century, with personalities like Maxwell and Kelvin speculating and ignoring criticisms and new evidence. Kelvin never accepted Maxwell’s displacement current or his theory of light, nor did he accept Rutherford’s interpretation of radioactivity. I don’t see how radical new ideas can be treated in any other way than as crackpot nonsense in the commercialised science of today. There is too much money at stake for democratic let alone liberal attitudes.
Peter said:
“As for other things to try, if you want to just think about how to quantize gravity, you are kind of stuck without having experiment to help you. In that case all you have to go by is mathematical consistency and elegance, and you need to behave a lot more like a mathematician”
Peter, you sounds like beginning to sing the praise songs of super string theoretists. Those are the exact arguments repeated many many times by super string theoretists:
1.QG is very hard because the technology is not available to do experiments, and super string theory is the clear winner, being the most hopeful theory. It just will take much longer time.
2.Super string theory is the only self consistent quantum theory of gravity, and it is so elegenat, so beautiful, so rich in mathematical structures and it is impossible that it could turn out to be wrong and irrelevant to nature.
I see no one ever attempted to dispute that two arguments, despite they being reiterated many times. And I see Peter is clearly nodding his head and hence ready to join the pro-super-string camp. Looks like the only complaint he still has is that “give some more money to none-super-string alternative approaches.”
I say No to both accounts. First on the self-consistency and elegance. A theory has to be logically self consistent to even begin to be considered. If it contradicts itself logically, then it’s automatically disqualified without having to do any experiment. So self-consistency is really a minimal necessary condition, and is far from being sufficient to say whether a theory is right or not. As for the elegance, it is NOT even a necessary condition. In history many more elegant theories are replace by counter parts that’s less elegant, but agree with experiment better. For example Newton Mechanics is certainly more elegant than Einstein’s SR and GR. Newton needs just one universal clock and one ruler for measurements. But Einstein needs lots of clocks and rulers in every corner of the room. Only when all things else considered are equal, then we prefer the more elegant one due to our natural human nature of appreciation of beautiful and elegant things.
Now on the experiment end, I say NO, too. There ARE very accessible, and already done experiments to check against theories. For example we have measured the cosmological constant, and know its value. So that’s one experiment evidence that’s out there, and none of the existing theory can explain why they can not come up with the correct value of CC. They try to get around that piece of hard experimental evidence by the anthropic principle and landscape craps of nonsenses, and then turn around to say there is NO experimental data available to further their theory research. That’s ridiculous!!!
Please try to explain the currently KNOWN, and UNEXPLAINED experiemental facts, before demanding experimentalists to discover more unknown and unexplained experimental facts! Please explain CC, explain why the supposedly ridiculously high vacuum energy density is not observed and none-exist, and explain other un-explained observational facts. Until you do that, we are in a situation where experiments far lead the theory, instead of theory being far more advanced than experiments, as some theoretists claim.
Quantoken
It seems the times piece would have been better titled “Lacking Hard Predictions, Theorists Try Democracy.� It is interesting that string theories inability to reproduce the predictions of quantum mechanics let alone make a precise prediction on what energy supersymetric particles or other stringy effects appear can be blamed on lack of hard data especialy when hard data such as the CC exists as Quantoken pointed out.
The Science writer also seemed to be under the impression that in 1984 “it was shown that a consistent theory of all the forces of nature could be constructed from strings.” Which is of course not even really true today let alone in 1984. Also the writer seems to not understand what Smolin means, or at least doesn’t point out to his readers with little knowledge of the anthropic principle, when he says “I’m not sure it will be the next revolution, but I am sure it will be the last,” and the same goes for the faith based initiative comment, which, along with the defensive comments about not everyone haveing to be a string theorist, lead me to wonder if there was a lot more negativity then implied at the end of the panel when it was opened to comments from the audiance.
Reply to Quantoken rant!
I have looked at your attempts at explaining the universe at:
http://www.livejournal.com/users/quantoken/
and frankly, if String Theory is Not Even Wrong well you are Not Even Right!
Let point out some facts. QFT does not explain the CC data or the asymptotic zero energy of the vacuum either! Nor does Loop Gravity or anything else. String Research ashould definately continue until some better comes along
Any SERIOUS suggestions!
hi Scot,
you mention a lot of evidence of pessimism but you include Smolin’s remark (about reformulating string/M to be background indep would be the last) which is extremely optimistic and hopeful, so it doesnt belong with the other cases. this is just a minor correction
you said…writer seems to not understand what Smolin means, or at least doesn’t point out to his readers with little knowledge of the anthropic principle, when he says “I’m not sure IT will be the next revolution, but I am sure it will be the last,â€? … a lot more negativity
IT does not mean Anthropery here, it means B-indep. Smolin’s message is that string has great potential but is stuck now, can’t be predictive and falsifiable, because they havent grappled with the problem of making it background indep
and that might not be the NEXT because there is no limit to how long they can or will procrastinate, but Smolin’s opinion is that it will be the FINAL reinvention of the field because that will be what it takes to bring it to a predictive falsifiable condition, which is all one can ask of a theory—the rest is testing.
he spells this out in “The Case for Background Independence”
http://arxiv.org/hep-th/0507235
where the main point is that background DEpendence is what is wrong with string and moving in the direction of INdependence makes theories have fewer assumptions and be more predictive. he says it is the way out of the Landscape.
this is a radical message, but it might be right. if it is right, then it is hopeful because there IS a clear way to proceed.
so there was nothing gloomy about Smolin epigram comment from audience, about B-indep not being the next but being the last.
he wasnt talking about Anthropistics. he was talking about weaning the field off the prior metric.
oh my bad, I thought the last comment by smolin was about anthropic and was disconnected from his previous comment on string theory not being background independent. Also I didn’t really think it was possible that string theory could be made background independent, that string theory was fundamentally background dependent, and so that helped add to my confusion.
I am going to disagree with you that the idea that a quantum gravity theory must be background independent, which i think to be highly likely, is in some way radical as I think the idea has been around since people were first trying to formulate a theory of quantum gravity.
that’s a friendly disagreement, Scott. I grant you could well be entirely right!
In his 2 August 2005 New York Times article, Dennis Overby says that “… string theory …” has achieved “… success in formulating a mathematically consistent theory that unifies gravity and the rest of nature …”.
If the Standard Model is included in “the rest of nature”, then where is the concrete example of a string theory model that does in fact unify gravity and the Standard Model ?
Although my E6 string model at http://www.valdostamuseum.org/hamsmith/E6StringBraneStdModelAR.pdf does unify gravity and the Standard Model, it is not supersymmetric, and so does not qualify in Dennis Overbye’s mind as a “string theory” because Dennis Overbye says “… Supersymmetry is predicted by string theory …”.
As far as I know, there does not now exist an example of such a supersymmetric “string theory” model that in fact “unifies gravity and the rest of nature”.
Further, Dennis Overbye’s article says “… What physicists most expect to discover with the Large Hadron Collider is a new phenomenon called supersymmetry (which would manifest itself as a passel of new particles) …”. In my opinion, at least a substantial number of physicists don’t believe in supersymmetry at all, because it has never been observed in searches that have seen all the particles of the Standard Model other than the Higgs. As to the Higgs, I thought that the primary motivation for the LHC was to study Higgs phenomena.
Tony Smith
http://www.valdostamuseum.org/hamsmith/
Tony, I’d not put the hand over the fire to swear that a given model is not supersymmetric. Just check Catto and Lichtenberg works; they are following the scent of SUSY between quarks and diquarks, Which has sense by two reasons: one from, cof, strings: that diquarks are allowed to sit in an extreme of the QCD strings, as quarks do. And other from the standard model spectrum: if you allow for “quark antiquark” diquarks (aka mesons), then the mu lepton is very near in mass to a family of diquarks, and the tau lepton is near to other one, so this SUSY extents to leptons.
Alejandro indicated that I should not swear that my model is not supersymmetric, citing possible supersymmetries more subtle than the 1-1 fundamental fermion – fundamental boson supersymmetry that is conventionally used in superstring theory.
I agree. In my comment, I should have said that my model does not have the simple 1-1 fundamental fermion – fundamental boson supersymmetry that is conventionally used in superstring theory. I expect that the simple 1-1 supersymmetry is what Dennis Overbye meant when he mentioned “supersymmetry” in his NYT article, so i t probably remains true that my model would not fall into the class of (super)string theories described by Dennis Overbye in that NYT article, and my point that I know of no Overbye-type (super)string theory model that does in fact unify gravity and the Standard Model remains unchanged.
I should also have pointed out that my model does have a correspondence between fundamental fermions and fundamental bosons. Although it is not a simple 1-1 correspondence between fundamental fermions and bosons (I have sometimes referred to it as a subtle supersymmetry), it is well-defined and may be useful in ultraviolet finiteness calculations.
Tony Smith
http://www.valdostamuseum.org/hamsmith/
Peter,
I’m curious whether you have any comment on the paper:
“Violation of Quantum Gauge Invariance in Georgi-Glashow SU(5)”
by Martin Ambauen, Gunter Scharf
http://arxiv.org/abs/hep-th/0409062
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