Democratic Vote Squashes Anthropic Principle

By JoAnne Hewett | August 2, 2005 7:51 pm

We have already heard about the panel discussion on the Next Revolution in String Theory at Strings 2005 from Clifford and Jacques. Today, it made the New York Times. It shouldn’t be a surprise that the NYT had a slightly different spin. The NYT paid some homage to the concept that by their nature revolutions can’t be predicted. Progress in science occurs when scientists work on questions that puzzle them rather than when they try to guess which questions might have the biggest payoff. Most of the NYT article was devoted to The Vote.

At the end of the session, a Vote was taken on whether the value of the cosmological constant is explained by the anthropic principle or by fundamental physics. Surprisingly emotional debates have been sparked by this issue. People either willingly embrace or really hate the anthropic concept. There is no in-between. In heated moments, the competing theories have even been compared to the difference between evolution and intelligent design.

This subject has been tackled many times before, but this is my first blog. I thus subject you to my brief no-nonsense phenomenologist’s description of these two trains of thought:

The Landscape: The anthropic paradigm arises from the realization that there are an extremely large, 10 to the 100-1000th power, possible vacua predicted by string theory. It is thus viewed natural that out of so many choices, at least one of these vacua spawns a universe with a cosmological constant with the extremely small value that we observe. This is known as the string theory Landscape. Interestingly, the Landscape picture has spawned a new version of Supersymmetry, called Split Supersymmetry, where some of the new particles in Supersymmetry are super-heavy and some are light. This has definite predictive signatures at the Large Hadron Collider which have been worked out by yours truly here.

The Fundamental route: Many believe that eventually all properties of the universe should ultimately be calculable from fundamental principles. This route asserts that fine-tunings of parameters are unnatural and the smallness of the cosmological constant will someday be explained. The absence of fine-tunings in nature also predicts that various classes of new physics should be discovered at the Large Hadron Collider. I’ve worked on this too.

The Vote revealed that the distinguished panel members were evenly split between the two choices. However, the audience voted overwhelmingly for the path of fundamental physics. Wow! Sitting at Stanford, I never would have guessed. The Vote holds no meaning, of course, but the results are interesting nonetheless and undoubtedly will become part of the debate.

CATEGORIZED UNDER: Science, Science and the Media
  • http://blogs.discovermagazine.com/cosmicvariance/sean/ Sean

    Aha! You obviously read my advice to Mark.

    My own view is here. I’ve long stressed that whether the anthropic principle is right doesn’t depend upon whether you like it or not; we might be stuck with it. But the more I think about it, the more skeptical I become that our actual universe looks like what we would expect if important parameters were selected anthropically.

  • Aaron Bergman

    After the vote, Marc Spradlin suggested that they redo it based on geography, getting a decent laugh.

  • graviton383

    My feeling about the landscape is that once you allow in fine tuning by saying that
    parameters are what they are by accident of choice, since there are 10^1000
    vacuum states, we lose all predictive power. (Of course, you could argue that we are trying to predict the wrong things..like the orbits of the planets.) The landscape doesn’t REALLY lead to split SUSY as one chooses to keep the coupling constant unification and a dark matter candidate `successes’ intact. But in principle there’s no reason for this except bias. It’s no holds barred.

  • Gordon Chalmers

    Joanne:

    I can imagine the debate over funding is this.

    Most physics including quantum field models and string
    models are integrable. Why does the government have to
    support research costing billions given this (which is
    probably a fact, also with large computing machines).

  • http://blogs.discovermagazine.com/cosmicvariance/joanne/ JoAnne

    Sean, beat ya to it!

  • http://www.livejournal.com Quantoken

    JoAnne said: “……It is thus viewed natural that out of so many choices, at least one of these vacua spawns a universe with a cosmological constant with the extremely small value that we observe……”

    The analogy of that would be that since there are almost 10^10 population in the world, so out of these many choices of people, the hope is there is at least one person with an extremely small value of height, maybe just 1/10 of the normal height, 6 inches?

    Of course 6 inch tall human being does not exist, despite the huge population. Now, what makes you think you can find a spiece of sample of cosmological constant which is not 1/10, but 10^-120 of the “normal expected value”, just because you have 10^500 vacuas to select from?

    You can safely rule out the possibility of a human of 1/10 of the height, despite of the huge population. Likewise you can safely rule out any vacua giving a CC 10^-120 fo the regular value, despite of the huge selection of vacuas.

    Quantoken

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    JoAnne, Have you ever considered writing newspaper headlines for a living? The title of this post is great. -cvj

  • http://blogs.discovermagazine.com/cosmicvariance/risa/ Risa

    As a naive astrophysicst unfamiliar with the nitty gritty of the landscape disputes, shall I assume that the believers in anthropic arguments typically come from the west coast (just like most believers in echinacia*)?
    (disclaimer: west coast hippie born and bred)

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    Maybe. Standford is certainly thought of as the home for a lot of the ideas whcih have been discussed in recent years in the stringy context. (But Weinberg, at Texas, is well known for having tried to seriously build anthropic arguments into modern particle physics. Lenny Susskind has been very vocal about string theory being the natural context in which such ideas might have a home due to the large number of vacua.

    Not sure where to point to as a stronghold for East coast anthropic effort. It is quite distributed. Maybe there is a different style on the East coast. The difference between the styles has been noted before on effort in other areas within string theory, and keeps the field in balance. (On a lighter note, the whole East Coast-West Coast thing was sort of covered a bit in the screenplay which showed up in week one.) -cvj

  • http://www.iac.es/galeria/erwin/ Peter Erwin

    As (another) naive astrophysicist unfamiliar with, etc. — how does this debate play out in the rest of the world?

    In listening to these discussions (including comments from places like Peter Woit’s Not Even Wrong), I sometimes get the impression that string theory is overwhelmingly US-based, much more so than some other fields of science.

    I know this can’t be completely true — Clifford treated us to his tale of summer meetings and research in the UK, and I remember Michael Green giving a talk at Queen Mary College on superstrings back in the late 1980s (it all went quite over my head at the time, so that all I can remember now is his accent).

    But still… it seems as though it’s almost all going on in the US, plus some in Canada and the UK. Is this really the case?

    (Granted, a conference in Canada will get North American attendees more easily than people from elsewhere, so casual references to East Coast and West Coast make more sense there.)

  • TM

    The anthropic principle is a case of conceptual confusion
    due to semantic ambiguity. Sometimes, it means, as in
    joanne’s post, that the laws of nature allow for the existence
    of human life, which is banally true. We exist as do bacteria,
    neutrinos and quarks. It’s important to know whether there’s
    one unique vaccum or not, but even if there is one unique vacuum,
    does it not mean that whatever physical law specifies that vaccum
    still needs to be explained; isn’t there always going to be an
    infinite regress? Isn’t the anthropic principle just something people
    grab on to at a given point of confusion.
    Then there’s the meaning of the anthropic principle that somehow
    our existence necessitates the laws of nature rather than being a
    consequence of them. That’s what gives it all the religious charge
    and makes it such a big deal. Let’s call it the bacterial principle and
    then the NYT won’t cover it.

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    Peter Erwin: – There is a vast range of different sorts of string theorists all around the planet. The articles you read in the press tend to give the impression that the only physics being done in this area (and several others) is done in America. If pushed, they’ll mention the United Kingdom too. Not accurate. There are leaders in the field in many countries doing excellent work. Frankly, the impressiont that the field is up in arms about anthropic vs non-anthropic is also overstated. Most people are *not* working on that issue. Several are -rightly or wrongly- not perturbed by it at all and are busily quietly working out several difficult issues with the theory, such as understanding what it really is, forming the foundation for the tools and ideas we’ll need in the future. All of these people are ignored by the press and the loud discussions on some blogs, but they should not be forgotten, as the history of the field teaches us. Cheers, -cvj

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    TM – The anthropic discussion is not just semantics. It is more fundamental than that. Have a look-see at the papers. Best, -cvj

  • TM

    Clifford – I don’t doubt that something is at stake in the dispute
    and I’m hardly qualified to understand much less judge it. However,
    I don’t understand why one invokes the term Anthropic Principle.
    I assume that as a principle it function like the principle of relativity
    did for Einstein, as something that one posits as true and then uses
    to deduce various things, like e=mc-squared, which one can then
    test empirically. How is the anthropic principle analogous? If I understand
    SEan correctly, it’s an empirical question: either there’s a unique vacuum
    or there’s a near infinite number. Why does the anthropic principle lead
    you to the latter position. Isn’t it just an ex post facto description of it?
    And isn’t it therefore semantically confusing? That’s what I don’t understand.

  • Kuas

    Actually the NYT article implies there are only 1060 vacua, which oddly enough is also the number of WMD they reported finding in Iraq.

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    I have some sympathy with your confusion. I tend to stay way entirely from phrasing that discussion that way. The issue boils down to whether you think that it is in principle possible to compute absolutely every one of the apparent parameters that we see in Nature, or whehter there are always some to be left undetermined. Then people get worried and start babbling about whether the values are as they are because we are here to observe them as they are.
    So you have the Stringevangelists on the one hand, and the Anthorpicists on the other hand.

    There is a third hand.

    I think that we should use the history of science to guide us. There is a never ending series of questions. There are always new vistas to be explored with better and better physical theories. There are questions that we don’t even know to ask, as they will not even make sense until we answered a whole lot of the current questions. This is the way science proceeds. ‘Twas ever thus.

    My position has been described by Mark as “philosophical”. I will agree, and say that this is neither a bad thing nor a good thing. It’s just a thing.

    -cvj

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    Hi – My previous comment was a reply to TM -cvj

  • http://www.math.columbia.edu/~woit/blog Peter Woit

    I didn’t find the result of the votes by the panel or the audience very surprising, since they corresponded pretty much to well-known views of the panel members and the huge lack of enthusiasm for the landscape I hear from string theorists I talk to. The thing about the article that really shocked me was the Michael Douglas quote:

    “We’ve done very well for the last 20 years without any experimental input”

    Can anyone confirm that he really said this? Would any other string theorists agree with him about this?

  • http://golem.ph.utexas.edu/~distler/blog/ Jacques Distler

    Which part of the sentence shocks you: the lack of experimental input part or the “We’ve done very well for the last 20 years” part.

    I presume the latter, since the lack of experimental input is fairly … umh … well-known.

    Why am I unsurprised that you are “shocked” by the statement that string theory has done well over the past 20 years?

  • http://www.livejournal.com Quantoken

    Jacques Distler:

    It’s a completely lie that you claim there has not be ANY experimental input! Of course there are PLENTY of experimental inputs. For beginner, the cosmological constant (CC) has been carefully measured and it’s value is known pretty good.

    This is one piece of experimental input that is solid, well defined and un-ambiguious. Now clearly you are unable to explain or say any thing about why CC is the value it is, and you have to invent the nonsense of landscapes and anthropic principles to cover the fact that you are simply inable to explain CC. And there is not even any hope that you could eventually explain it.

    What good it is to feed you more new and un-explained experimental data, when you can not even digest the already exist ones?

    Quantoken

  • http://www.math.columbia.edu/~woit/blog Peter Woit

    OK Jacques, I guess you’re one string theorist who agrees with Douglas about this. I suppose I’m not surprised. Any others?

  • http://golem.ph.utexas.edu/~distler/blog/ Jacques Distler

    OK Jacques, I guess you’re one string theorist who agrees with Douglas about this.

    You still haven’t said what “this” is?

    I was asking for you to clarify your question before I hazarded an answer.

  • http://www.math.columbia.edu/~woit/blog Peter Woit

    I was shocked by Douglas’s statement because just about every theorist I know would say that the past twenty to thirty years have been a tough time for particle theory, for string theory and for all other approaches, with the main reason being the lack of any experimental input about how to get beyond the standard model. Douglas seems to be saying the opposite, that not only has string theory not suffered because of this, but has “done very well” (note that you misquote him in your rhetorical question).

    Since Douglas mentions the lack of experimental input about getting beyond the standard model, from context his “has done very well” must be an evaluation of how well string theory over the past twenty years at getting beyond the standard model. So would you agree with him that since 1984, string theory has “done very well” at getting beyond the standard model?

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    Hi Peter,

    From your last comment (23 above), maybe you’re being a tad unfair. I think that you might be putting words into Mike Douglas’ mouth and then being shocked by them. Your last question to Jacques above is not about what Douglas was quoting as saying, and is only your interpretation of what exactly “done very well” was referring to.

    Perhaps it is not so shocking if maybe “done very well” was referring to developing the framework of string theory, as opposed to “done very well” at going beyond the standard model in specific terms. I’d be shocked if he was implying that he was saying that we’d “done very well” at interpreting experimental input that, in your words above, is lacking. That would be logically inconsistent, no?

    Cheers,

    -cvj

  • http://blogs.discovermagazine.com/cosmicvariance/sean/ Sean

    It’s not been the best time for “particle physics” over the last twenty years, not for lack of data, but just because the theory is so good that none of the data is surprising. That will presumably (or at least “hopefully”) end with the LHC.

    I presume that what Michael meant was that we’ve done very well at learning about string theory. And I would agree; we know a lot more about string theory now than we did twenty years ago — although there’s a tremendous amount that we don’t know. Determining whether or not string theory describes nature will, obviously, require more detailed confrontation with data. Everyone thinks that more data would be great, and would make our lives more interesting and exciting; but I can still be impressed with the progress string theorists have made in understanding the theory in the absence of direct experimental input. (Plenty of “indirect” input, of course — namely, every experiment relevant to field theory and/or gravity.)

  • http://golem.ph.utexas.edu/~distler/blog/ Jacques Distler

    And I would agree; we know a lot more about string theory now than we did twenty years ago — although there’s a tremendous amount that we don’t know.

    I would go farther: string theory has turned out to be a vastly more beautiful and intricate subject than anyone suspected 20 years ago.

    If it were as simple (“simple” is very much a relative term!) as everyone then thought, we would surely have completely understood it by now. That a complete understanding seems as far away as it does is a measure of the richness of the theory, not of how little progress we’ve made in understanding it.

  • http://www.math.columbia.edu Peter Woit

    Hi Clifford, Sean and Jacques,

    You’re probably right that what Douglas had in mind when he says string theory has “done very well” without any help from experiment was the progress made in understanding string theory itself. My interpretation was colored by the experience of challenging him when he was last here in NY to give a single example of a prediction that might come out of his current research program. He was unable to do this and yet simultaneously kept going on about how wonderful string theory was. This seemed to me very bizarre and I interpreted his more recent comments as being along the same lines.

    But I’m afraid I still have to disagree with all of you if you think that the claim that string theory has “done very well” over the past twenty isn’t shockingly counterfactual. Any evaluation depends on one’s grading system, but the bottom line for any physical theory is whether it makes predictions. In the case of string theory it is undeniable that more than twenty years of effort by thousands of the smartest people on the planet has not led to a single prediction, and it is also hard to deny that all this work has left the field in a state where there aren’t even any plausible ideas about how to ever do a calculation that would lead to a prediction. Lawrence Krauss accurately refers to this as a “colossal failure”, and in the face of failure of this magnitude to be claiming that string theory has “done very well” is just absurd.

    While it is undeniable that this huge effort over the last twenty years has unearthed some interesting structures, the goal of finding some simple, beautiful underlying structure to which perturbative string theory is an asymptotic expansion seems farther away than ever. Over the last twenty years I’ve watched people try out many ideas for what such a thing might be, many of them beautiful, but they have all failed miserably, and given this situation it makes no sense to be saying string theory has “done very well”.

    I find Jacques’s claim that string theory has turned out to be vastly more beautiful than anyone suspected 20 years ago to be a breathtaking denial of reality. About aesthetics there’s always the problem of “de gustibus…”, but the fact of the matter is that what progress there has been in string theory during the past few years has consisted in the realization that probably an infinite number of hideously complicated constructions give different consistent versions of the theory (if the theory has any consistent versions at all). If you refuse to accept my judgement that these things are ugly, then consult the biggest proponent of the landscape idea, Lenny Susskind, who is going around gleefully arguing that string theory is inherently extremely ugly and complicated, but that this is a good thing.

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    Hi Peter,

    One of the reasons I like talking with you is that you clearly do listen and reconsider your position if presented with a solid alternative view backed by some argument. So let me say that I appreciate that you admit that perhaps you were stretching Mike Douglas’ words rather a lot. Thanks.

    In turn, I will agree with you that there are perspectives from which it can be said that there is disapppointment about where string theory is right now. But actually, my own perspective does not have that profound disappointment of which you speak because I always was in for the long haul. I don’t see string theory as just another small theory that tinkers with the stuff that came before and we get to fiddle a bit and see if it gets the next level right or not. No, I actually think it is (a piece of) something huge. The scope of what it is potentially able to do for our approach to, and appreciation of, fundamental physics is so profound that I just don’t think that 20 years is nearly long enough to begin being concerned. Nevertheless, do not be under any illusion that I think that string theory will be the “final answer” or any of that charmingly juvenile hokum. I don’t. I’ve said to you before and elsewhere on this blog that I am not a Stringevangelist. Strings, etc, will come, find their place in our description of Nature (perhaps) and then be overtaken by other theories in the long run, which will be better at answering whatever new questions there will arise that we cannot even conceive of now. Right now, I happen to think that it is part of the next “great leap” and/or “great synthesis” that we will make, along the lines of Special and General Relativity and Quantum Mechanics in recent times, and other great syntheses/leaps in history such as those of Newton or Galileo. Think for a while about how astonishing those pillars of our field are and ask how long you would have been happy to wait. Then imagine something that puts them together, while probably removing the idea of spacetime as fundamental at the same time. How long are you prepared to get that story to come out right? 20 years? 200? More?

    One thing that we should not overlook, in addition, is the powerful toolbox that research into this area is providing us with. Leaving aside of where we get in our lifetimes with strings, I am firmly convinced that this aspect will continue to grow: Stringy or string-inspired tools and approaches will allow us to learn more about the structure of gauge theory and related theories and be able to apply them to real physics questions. It will allow us to find more techniques for doing things (like the twistor approach teaching about scattering amplitudes in Yang-Mills) that are unddeniably useful. Isn’t some of that worth 20 years?

    Best,

    -cvj

  • Aaron Bergman

    I find Jacques’s claim that string theory has turned out to be vastly more beautiful than anyone suspected 20 years ago to be a breathtaking denial of reality.

    The beauty here is all about where you look. I would agree that the vacuum picture is giving indications of a rather unfortunate ickiness (a point of view that’s not universal, I think), but that doesn’t mean that there isn’t plenty of beauty elsewhere. AdS/CFT and the ideas that surround it are a startling new insight into (some) gauge theory. The relationship of strings, particularly topological ones, with mathematics has led to ideas of incredible beauty. That the five previously known string theories all seem to be decoupling limits of some ur-theory is yet another striking feature that no one anticipated in the original theory. It seems to me that you’re missing the rather large forest simply because of one hazy but not particularly pleasant -looking tree.

    And who knows. Maybe if we get a better look at that tree, it could even surprise us.

  • http://travisgarrett.blogspot.com Travis Garrett

    “Fundamental rules on one scale of space and time may reveal themselves to be the results of frozen accidents on a larger scale.” – Murray Gell-Mann, Santa Fe Institute Proceedings Volume XXII

    “… For no matter how complete the description of a state may seem today, the history of physics teaches us that sooner or later new experimental facts will come to light which will require us to improve and extend the model to give a more detailed and usually more complete description.” – Eugen Merzbacher, Quantum Mechanics, 3rd edition.

    I suspect that a hybrid version of the landscape is correct, as I believe Clifford may also be implying. It seems likely to me that our local universe is just one of many different meta-stable vacua that are possible in string theory, and that chaotic inflation is a plausible mechanism for generating lots of these different vacua. It has the ring of veracity, as opposed to the stringevangelist position – it seems unlikely to me that string theory would inevitably dynamically evolve to only our effective field theories, which also just so happen to have the right masses and low energy coupling constants and mixing angles and so on to produce the lots of stable atoms and long-lived stars that needed for animals to evolve. Furthermore, in the hybrid landscape proposal, we will indeed keep on discovering new things and expanding our theories (‘Twas ever thus – as Clifford put it), and find compelling experimental evidence that our universe is just another solution – stuff like Nima and Savas have been proposing. It will emphatically not be Porky the Anthropic Pig popping up and declaring “That’s All Folks!”

    I also think that it is quite likely that we will keep on finding new phenomenon that will require us to keep on expanding our theories indefinitely (just as we have seen to date with Keplers laws being a special case of 1/r^2 gravitation which is a special case of Newtonian dynamics, which is a slow speed, weak field approximation of general relativity and a large scale limit of quantum mechanics, which itself is a slow speed, constant particle approx. of QFT, which are in turn possible low energy limits of string theory, etc., etc…). Furthermore, this “Physics is bottomless” idea is the statistical conclusion one reaches once a few natural assumptions about reality are made. First assume that a complete description of our universe is possible, and thus our universe actually is a mathematical structure. Then assume that all mathematical structures exist – that is, our universe is just another type of structure, and isn’t entitled to any special status just because it happens to contain observers. Name this giant collection of mathematical structures the ensemble (Tegmark has popularized this idea recently). But then there will be a whole class of structures in the ensemble that contain our universe as a particular limit. A few members of this class won’t be much more complex than what we have discovered to date, but the vast majority will be much more complex, and the aggregate effect of all of them is that we will always be discovering ever deeper laws. In fact, this is a sort of meta-prediction: if it is correct then we will indeed keep on discovering new things, so that science and technology keep on progressing at a exponential rate, and if it is wrong then progress will level off for good at some point, as on a sigmoidal curve. We’ll see!

  • http://www.math.columbia.edu/~woit/blog Peter Woit

    Hi Aaron,

    The problem is that the ickiness of string theory increases dramatically as one tries to actually use it to do unification. When going on about the successes and beauties of string theory, if one is honest one should add the parenthetical comment (by the way, this doesn’t refer to the main motivation always given for doing string theory, unification, which has been a complete failure so far and led to truly hideous constructions).

    I don’t think any conclusions can be drawn about the beauty of M-theory until you know what it actually is. The more beautiful precincts of the string theory program are the ones that are largely QFT (2d topological and conformal theories, AdS/CFT), which I think people should take as a big clue.

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    It is a clue we are well aware of Peter, and encouraged by. Thanks. But note also that the reason those field theory examples appear to be more beautiful to some people is because they are in a more familiar context. One “gets it” more if field theory is involved.

    -cvj

  • http://www.math.columbia.edu/~woit/blog Peter Woit

    Hi Clifford,

    I think the problems particle theory is facing are very difficult, some big new ideas are needed, and it’s hard to know what time-scale will be required for progress. But, not being immortal, I can’t help being unhappy that the first half of my career (I finished grad school in 1984) has been completely dominated by what I thought from the beginning was a speculative idea that wouldn’t work, and determined to do what I can to stop the same thing from going on for the next twenty years.

    What really upsets me about string theorists refusing to acknowledge the failures of the field and claiming that everything is fine and that the past 20 years has been a great success is that these claims are being used to both prop up continued research in failed directions and to discourage people from trying other very different ideas. If it’s so clear that string theory is the route to a glorious new understanding of space, time and fundamental physics, why should any bright, ambitious young theorist even think of working on anything else? If some people want to spend the next 20 years that will probably make up the rest of my professional life pursuing string/M theory, that’s fine, but they should be willing to admit that so far things have not gone as well as they hoped, and should be thinking about how to make space in the field for other ideas that might be more promising.

  • Aaron Bergman

    The more beautiful precincts of the string theory program are the ones that are largely QFT (2d topological and conformal theories, AdS/CFT), which I think people should take as a big clue.

    It’s simply not true that either of those are largely QFT. AdS/CFT relates a QFT to a string theory, and the latter is at least as important as the former. Also, it is not just topological sigma models; there is the topological string which has been important and is not just a QFT.

  • Moshe Rozali

    Hi guys,

    These conversations have a fixed point (or a limit cycle) behavior… but there is one argument I have not heard mentioned much, which is the diversity and fluidity of what is called (now already somewhat misleadingly) string theory. This is a very large subject consisting of many loosely connected techniques and goals. If some bright person comes up tomorrow with a great idea related to formal aspects of field theory or quantum gravity, lots of people will get very interested, and she or he would probably end up being classified as a string theorist…

    A very good example again is the twistor string story, which is inseparable from the main body of string theory, but is certainly a different strand. I think many people are not motivated so much by the grand goals, rather they are kept stimulated by the continuous unraveling of new and interesting ideas. The naming and classification of those ideas is not that important, we can leave it for future historians of science.

    best,

    Moshe

  • andrew

    For what it’s worth, the Compton Gamma-Ray Observatory Burst Symposia took a vote on Gamma-Ray Bursts at every meeting: Galactic or Cosmological? Galactic always won by a landslide; until the evidence started coming in for correlation with galaxy distribution. Still, Cosmological never broke 50% until BeppoSAX localized a gamma-ray burst inside a galaxy. Nobody batted an eye, of course; the votes were just a fun diversion and every scientist is ready to throw over a beautiful theory for an ugly fact.

  • http://golem.ph.utexas.edu/~distler/blog/ Jacques Distler

    This is a very large subject consisting of many loosely connected techniques and goals. If some bright person comes up tomorrow with a great idea related to formal aspects of field theory or quantum gravity, lots of people will get very interested, and she or he would probably end up being classified as a string theorist…

    A very good example again is the twistor string story …

    Quite so.

    And, even if we restrict to the past few years (a “slow” period in our field), Peter’s claim of lack of progress only makes sense if, by progress, you mean the particular narrowly-construed definition of Comment 23.

    Some more examples of real progress from the past few years:

    Berenstein-Maldacena-NastaseDijkgraaf-VafaMinahan-Zarembo/Beisert-Kristjansen-StaudacherOoguri-Strominger-Vafa

    to pick a few papers off the top of my head which brought fantastic new insights (and which spawned many interesting followups).

    I even disagree with Peter’s characterization of what the important insight of KKLT (and the many followups) is. But, given the sharp disagreement, among people who understand the subject, one can hardly fault Peter’s interpretation.

  • Chris

    From Clifford:

    I don’t see string theory as just another small theory that tinkers with the stuff that came before and we get to fiddle a bit and see if it gets the next level right or not. No, I actually think it is (a piece of) something huge.

    Why do we need something “huge”, when there is so few observations standing in need of an explanation that goes beyond the Standard Model? The postulation of a vast level of complexity currently inaccessible to our observational tools and techniques strikes me as gratuitous (to put it mildly). In general, string theory has come to resemble a huge software development project involving hundreds of people that is way over budget and way behind schedule. There are pieces of interesting and technically impressive work scattered throughout the enterprise, but the overall effort is starting to resemble a massive boondoggle.

    I think something conceptually profound, and in that sense “huge”, is needed, but this should not be taken to imply that there is vast world of unsuspected phenomena and physical structure waiting to be discovered. Of course, assuming that such a vast world exists means that everybody will have lots to do. Don’t think hard, just work hard…

  • Thomas Larsson

    Moshe,

    It is very unlikely that string theorists would recognize a good, alternative idea to quantum gravity. The problem is the central dogma in string theory: that gauge symmetries always are a redundancy of the description and that all gauge anomalies thus are inconsistent. This is manifestly false. Counterexamples include the subcritical free string (not the interacting one) and the chiral Schwinger model in 2D, which do not violate unitarity. The former is of course especially relevant to quantum gravity, since the free string is nothing but 2D gravity coupled to scalar fields. Using this analogy, Roman Jackiw has forcefully argued that also 4D gravity must have similar gauge (diff) anomalies, in gr-qc/9511048.

    But why care about facts? Since the inconsistency of every gauge anomaly is a dogma, we can declare that the counterexamples to be wrong by royal fiat. Consequently, the Virasoro-like extensions of the diffeomorphism algebra in 4D cannot have anything to do with 4D quantum gravity. The only disturbing thing might be that GSW themselves explicitly state that the subcritical free string is ghost free, in section 2.4. But such a nitpick cannot of course change our conviction that every gauge symmetry is redundant.

    And to generalize the Virasoro algebra beyond 1D is of course such a trivial thing that it does not even qualify as mathematics.

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    Chris,

    You say we don’t need something huge. I very much disagree.

    Even though there’s been not a large amount of raw data in recent years, let us (and others in this conversation) not forget that it has been clear for decades that there are several profound questions in particle physics in need of an answer. Now these may all have different answers in disconnected mechanisms, but intuitively, it seems that they are all connected, in the sense that a new level of understanding of what we are doing is needed (dealing with quantum fields in fixed background curved spacetime, just won’t cut it, for example) and if history is anything to go by, it is a good bet that we shoudl be looking for a common solution to many of these long-standing questions. No “little” theory is going to address all of those.

    Among the things that spring to mind immediately (and then I must go back to a calculation):

    (1) Dark Matter
    (2) the undetermined parameters in the standard model
    (3) the random patterns in the standard model, (number of light familes, etc)
    (4) The cosmological constant (either zero or very small….hard to explain with any theory right now)
    (5) Dark energy
    (6) The hierarchy problem (just how do you spell that?)
    (7) The very early universe and all the questions there about inflation, initial coditions…etc.(we desperately need quantum gravity here, and I’d be versy surprised if it were then not connected to (1) (4), (5)….)

    I could go on, but I think the case has been made….

    The point is that we could all be wrong. Maybe we should just tinker a bit more
    with what we have, but I hope that you agree that it would be at best *negligent* if we did not at least explore this structure that has turned up and hinted at us so lustily.

    -cvj

  • http://www.math.columbia.edu/~woit/blog Peter Woit

    Aaron,

    Much of what has actually been worked out about AdS/CFT relates the CFT just to another QFT, supergravity, not to the full string theory. It’s also sometimes claimed that AdS/CFT finally solves the problem of what non-perturbative string theory is: a QFT in one lower dimension. The 2d topological string, at fixed genus, is just a QFT (a topological sigma model coupled to 2d-gravity). It seems to me that you only get something which isn’t really QFT when you do the specific sum over all genera corresponding to string theory, and most results in the field don’t involve this.

    Moshe,

    You’re right that string theory is now a very large and diverse collection of different things, and if someone does anything new related to any of these different things, people will take an interest in it and start calling it string theory. But the other side of the coin is that people involved in the string theory project are now often convinced that anything not somehow related to the string theory program is not really modern particle theory, and that anyone working on stuff not related to the string theory program is just dimwitted and behind the times. Although I suppose one could camouflage one’s work on quantum field theory by claiming that one is just studying a brane (I can think of at least one interesting paper that does that).

    Jacques,

    I don’t think it is unreasonable or a particularly narrow construal to, after 20 years, ask to see some progress towards that goal which has been the main one used to sell the theory to the public and the rest of the physics community. If string theorists want to acknowledge that you can’t unify physics this way, but may be able to solve QCD and generate new ideas in algebraic geometry, that would be great.

    About how “fantastic” the work you cite is, well, de gustibus…. But glad to see you’re at least acknowledging that recent years have been a slow period, even if you do put “slow” in quotes.

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    Peter said “Much of what has actually been worked out about AdS/CFT relates the CFT just to another QFT, supergravity, not to the full string theory….”

    cvj says: Um, sorry, but no, no, and *no*. Your information on this is very out of date. Sorry.

    -cvj

  • http://www.math.columbia.edu Peter Woit

    Hi Clifford,

    I wasn’t that none of the AdS/CFT work relates a string theory to the QFT, I’ve been to several nice talks where people do that. Also to a lot where they don’t….

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    But Peter, it is *precisely* when the situation is interesting (i.e. the field theory is non-conformal) that we learn that we are *driven* (e.g. by RG flow) to consider the stringy completion of the dual gravity theory. So that’s why I disagree with the spirit of your statement, if not the precise wording. And I haven’t even started talking about all of the various field theory operators that you can construct, even in the conformal cases, that demand that you have strings and various branes on the “gravity” side. So I forcefully but respectfully disagree with the entire thesis of the first paragraph in your comment 41. I think that your facts are just out of date here.

    Cheers,

    -cvj

  • Moshe Rozali

    Peter,

    Again, not precisely what I said, but we can leave this to the next round, I think our hosts may return to this basin of attraction sooner or later.

    best,

    Moshe

  • Gordon Chalmers

    As a comment, I would like to point out in the context of AdS/CFT that modular functions tend to point out a different interpretation of N=4. The general modular functions are Eisenstein which are required by S duality.

    It really hasnt been clarified what to do with the (p,q) dyons in the theory, as the expansions indicate lots of perturbative corrections which arent directly the perturbative N=4 guage theory we find in the Lagrangian.

  • Aaron Bergman

    Peter,

    In addition to the various things Clifford mentions, I’ll also throw in the work by Berenstein-Maldacena-Nastase (which Jacques also mentioned) where we can actually honestly quantize the string in the plane wave background and relate it to various operators in the SYM theory.

    As for the topological string, by your definition, the entirety of perturbative string theory is just QFT on the worldsheet and, thus, not string theory at all. One might suspect that your classification here is just a tad tendentious. If looking at the genus expansion (and yes, people do care about the whole genus expansion) isn’t string theory, then I don’t know what is.

  • Gordon Chalmers

    Lets say that if you SL(2,Z) complete N=4 with the (p,q)dyons, interacting as gauge multiplets, that there seems no conflict. One can almost justify it from the zeta functions in the modular expansion.

  • Aaron Bergman

    Jacques has mentioned that it might behoove me to elaborate a bit further on my parenthetical remark. The whole topological string is important, even beyond perturbation theory. Things like Gopakumar-Vafa, Donaldson-Thomas, and many more are more than just statements about particular orders in the genus expansion.

  • http://golem.ph.utexas.edu/~distler/blog/ Jacques Distler

    Things like Gopakumar-Vafa, Donaldson-Thomas, and many more are more than just statements about particular orders in the genus expansion.

    Gopakumar-Vafa, Donaldson-Thomas Theory, the Topological Vertex, Okounkov-Reshetikhin-Vafa, …

    It would have been tendentious to claim that physical string perturbation theory is “just” 2D quantum field theory. To claim that Topological String Theory is “just” 2D quantum field theory is flat-out wrong.

  • Chris

    Clifford, you misunderstood me. I said this:

    I think something conceptually profound, and in that sense “huge”, is needed, but this should not be taken to imply that there is vast world of unsuspected phenomena and physical structure waiting to be discovered.

    I agree that we have several clues (such as the familiar ones you mentioned) which are quite possibly (probably?) interrelated. If string theory or an alternative can account for them, and show how they are related, that would be wonderful. However, if this is done by postulating a vast world of potential phenomena, of which these observations are just a minimal manifestation, then it seems to me that we have vastly overshot the target. Someone might respond: “But look at all the potential tests for such a theory! Isn’t that what we want — predictions of things that might exist, which we can go out and look for?”

    No! We want a restrictive explanation, one that says what cannot exist beyond the things we know must be explained. Isn’t such a theory at risk whenever we make new observations, especially in previously unexplored domains? Absolutely! If it fails to account for those observations, then we have learned something. If we can say in advance that the theory is so goddamned rich it can account for anything, then the theory is irrefutable and epistemologically worthless.

    In other words, our theory must account for what we don’t observe at least as well as what we do observe.

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    Yes, Chris, you’ve carefully explained the basic scientific process to our lay audience. Thanks. To yur point: Until we’ve actually carried out the research into the theory, how can we determine whether it is what we want or not? I jsut don’t see what all the fuss is about. It is clearly a highly under-developed theory. 20 years, or even 30 is a *drop in the bucket* of how long it could take to do something truly profound. We’re not playing to the MTV generation here. We need a long attention span to ride this puppy to the end and see what it gives. Also, it is not like there is a single other candidate out there that even *barely* hints at being able to address all of those items on the list which you agreed are probably connected. And even if there were (I can see Peter reaching for his keyboard!), would it not be highly negligent, I repeat, not to explore this one somewhat, and put the manpower into exploring such a thing, which would indeed need a lot of manpower if it were truly worthwhile? (And before anyone tiresomely objects to the use of the word “manpower” I hasten to point out that I mean it in a gender-neutral sense.)

    -cvj

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    Wait, Wait. Chris, I have to go a bit further. By your line of reasoning, you would have denied Einstein grant support on the basis that:

    (1) we don’t want to know all that stuff about space and time and simultaneity, and spacetime, etc, we just want to understand electrodynamics a bit better.

    (2) we don’t want to know about all that warping of spacetime and weirdo stuff like that, and certainly don’t want all that tensor calculus showing up, we just want to understand a bit better why Mercury’s orbit doesn’t quite fit Newtonian predictions.

    Now look where we are intellectually and scientifically as a result of someone taking a long time to work out seemingly speculative but nonetheless solid lines of reasoning right to their logical conclusions.

    At this point, the tedious point about effort in string theory being equivalent to hundreds of Einsteins working for decades will be brought up. Ok, go for it someone. Go on, make my day, make that brilliant point. Please.

    -cvj

  • Chris

    If people like Leonard Susskind weren’t saying that we need to stop worrying and learn to love the Landscape, as in “.. this has created a sort of sense of denial about the facts about the theory. The theory is going to win, and physicists who are trying to deny what’s going on* are going to lose”, then my insistence on these points would be much less relevant. Susskind is apparently willing to accept this conclusion with equanimity because he sure string theory is right, and that the Landscape follows from it inescapably. Evidently he sees little point in asking deeper questions about the presuppositions of string theory itself.

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    Chris: Susskind is one guy. A remarkable guy who deserves a lot of respect. But his opinion (and it is only an opinion -he would be the first to tell you this) does not make the whole of string theory, nor does it represent that of the entire community. He’s pushing his idea and he is a master at pushing hard. But it is only an idea. Time will tell.

    Cheers,

    -cvj

  • Jack

    Clifford said:
    At this point, the tedious point about effort in string theory being equivalent to hundreds of Einsteins working for decades will be brought up. Ok, go for it someone. Go on, make my day, make that brilliant point. Please.

    Sorry, I won’t! Because Einstein was a loser anyway! Remember, GR didn’t *predict* the perihelion precession — it was already well known! And as we know, PREDICTION is what physics is all about! So GR was a failure, just like string theory.

    Maybe I had better put one of these :-) here, just to be on the safe side…..

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    Sweet. What can I say? ‘Nuff said. :-) -cvj

  • Gordon Chalmers

    By the way, I solved the D-terms for general N=2 NLSMand the work appears on Monday. A short paper which describes the metrics for general torics.

    This is a bit off topic, but the result should be useful to string theorists and QFT theorists.

  • http://www.math.columbia.edu Peter Woit

    Aaron and Jacques,

    Instead of vigorously objecting to something I didn’t write (and wouldn’t ever claim):

    “Topological String Theory is “just” 2D quantum field theory”

    can you explain to me what is wrong with what I did write:

    “The 2d topological string, at fixed genus, is just a QFT (a topological sigma model coupled to 2d-gravity).”

    I’m not trying to deny that when you look at the full topological string theory by summing over genera you get mathematically quite interesting things. But you also get mathematically interesting things looking just at a fixed value of the genus.

    Clifford,

    I’m afraid I didn’t do a very good job of making my initial point, instead seeming to say something stronger than I intended. I’m not trying to imply that the string dual of a QFT is not something quite interesting and important, whenever you can find such a thing. If one ever does find such a thing for QCD that will be truly fantastic. But while the effort to find string duals for QFTs has had real successes, the program of completely dumping QFT and looking for a string theory TOE has been a complete failure. I’m not objecting to the philosophy that string theory may be the right way to understand some features of QFTs, but do object to the philosophy that QFTs are only interesting as low energy limits of string theories.

    And, having hassled you enough, I won’t reach for my keyboard to try and spend time arguing about whether the level of effort the physics community is devoting to string theory is appropriate or not. Maybe some other time…

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    Thanks Peter. I’m not sure who you are attributing “the philosophy that QFTs are only interesting as low energy limits of string theories” to, but bear in mind my earlier remark to Chris that because you may have heard some famous string theorist say something loudly with which you disagree, it does not mean that you should hold it against every other string theorist, and the entire program of research into string theory.

    Best,

    -cvj

  • http://golem.ph.utexas.edu/~distler/blog/ Jacques Distler

    can you explain to me what is wrong with what I did write:

    “The 2d topological string, at fixed genus, is just a QFT (a topological sigma model coupled to 2d-gravity).”

    I was going to let that slide, but since you insist on bringing it up …

    That statement is the precise equivalent of

    Quantum Field Theory at fixed loop-order is just a sum of iterated integrals.

    with the clear implication

    Why are those field theorists getting so hoity toity? All they’re really doing is elementary calculus!

    If anyone said that to you in a comparable discussion about QFT, you would, I expect, conclude that they were not a serious interlocutor.

  • Aaron Bergman

    Peter,

    Let’s remember where this all started. You said

    I find Jacques’s claim that string theory has turned out to be vastly more beautiful than anyone suspected 20 years ago to be a breathtaking denial of reality.

    and I responded that both the topological string and AdS/CFT contain things nobody expected twenty years ago and are quite beautiful. Now, you claimed

    The more beautiful precincts of the string theory program are the ones that are largely QFT (2d topological and conformal theories, AdS/CFT), which I think people should take as a big clue.

    Now, if you want to claim that you were only referring to fixed genus computations there, do you see how it’s nonresponsive? It is true that, just like the peturbative string, the topological string at a fixed genus involves a QFT calculation, but that has little bearing on the beauty of the full topological string theory which is more than just a bunch of sigma-model computations.

  • http://blogs.discovermagazine.com/cosmicvariance/joanne/ JoAnne

    Hi All,

    This has been a very interesting discourse! As a data-driven theorist, let me just say that I believe things will be very different 3 years from now. The LHC will be in the middle of its first real physics run in 2008 and I bet there will be all sorts of wild events. Some fraction will be real, and we will all have a heyday trying to explain them (the rest will be due to a misunderstanding of the background – recall that UA1 “discovered” SUSY only to find out it was the tau – or of the detector). It will be much more complicated than we realize to determine the actual underlying physics. The challenge may be so interesting that people may even stray away from string theory. I’ve been waiting my whole life for this, and I can’t wait!

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    Hi JoAnne,

    “Data-driven theorist”. I like that. You slapped us wild speculators down appropriately! I’m excited about the LHC too. It is appropriate to recall a remark from Andrew earlier in this thread (36): “every scientist is ready to throw over a beautiful theory for an ugly fact”.

    And I would not be surprised if the facts that we learn from the LHC eventually turn out to be part of a story just as beautiful as anything we could have thought of.

    -cvj

  • http://www.math.columbia.edu/~woit/blog Peter Woit

    Aaron,

    I try to choose my wording very carefully when I write in a forum like this, because by now I have a lot of experience with the phenomenon of certain people ignoring whatever point I’m trying to make and doing everything they can to try and find some way of interpreting my words as evidence that I don’t know what I’m talking about. This is kind of tedious, because it’s not really possible to combine concision of expression with absolute unambiguity. In the case at hand, when I referred to the “2d topological and conformal theories” part of the “string theory program” as being “largely QFT”, I suppose I could have added some sentences making explicit that I was well aware that for some specific 2d topological theories there were mathematically very interesting results about the full expansion in the genus of the worldsheet, and that that was why I was saying “largely QFT” not “nothing but QFT”. When you complained about my original comment I elaborated on it, making an accurate statement about the special case of the topological string: at fixed genus it’s a QFT, but the full series is not a QFT, and that’s one reason I was using the qualifier “largely” to refer to the entire class of 2d topological and conformal models.

    Your response to this elaboration has been to ignore it, and continue criticizing my initial unelaborated comment. I don’t understand why you are doing this.

    Jacques,

    Actually

    “”The 2d topological string, at fixed genus, is just a QFT (a topological sigma model coupled to 2d-gravity).”

    is not the precise equivalent of

    “Quantum Field Theory at fixed loop-order is just a sum of iterated integrals.”

    At this point, if I behaved like some people, I would start going on about exactly how those two statements differ, commenting that only someone really ignorant about QFT would think that they were “precisely” the same. But I don’t do thngs like that.

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    Ok guys, I know that this is JoAnne’s thread, but I think this is a good point to stop this particular dog-fight on this particular point while still retaining some shards of dignity on both sides. Let’s all agree that you’re all really smart, well-informed blokes with big muscles. Lick your wounds (if any), sheathe those daggers, and live on to fight again on another glorious day or thread in the name of Physics!

    Do come back. It has been useful discussion.

    See you then. Cheers.

    -cvj

  • http://golem.ph.utexas.edu/~distler/blog/ Jacques Distler

    At this point, if I behaved like some people, I would start going on about exactly how those two statements differ, commenting that only someone really ignorant about QFT would think that they were “precisely” the same.

    The Feynman rules for QFT say: the g-loop amplitude is computed by doing the following (sum of) integral(s). (We draw little pictures, as mnemonics for writing down the integrals in question, but that’s what they are: mnemonics.)

    The Feynman rules for (Topological or physical) String Theory say: the g-loop amplitude is computed by doing the following 2D QFT calculation.

    One (trivial) way in which these differ is that, in the QFT case, one is instructed to compute a sum of integrals. In the String case, there is just a single “string diagram” to compute. Otherwise, they look precisely analogous to me.

    I would be interested in hearing why you think they are not precisely analogous. It would be rather diagnostic.

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    Ok, it’s on ! Let’s see who’s the last man standing. -cvj

  • http://golem.ph.utexas.edu/~distler/blog/ Jacques Distler

    Sorry, Clifford. Our comments crossed in the æther.

    I retract my explication of the parallel contructions of QFT and String perturbation theories, as being needlessly inflamatory.

  • http://www.math.columbia.edu/~woit/blog Peter Woit

    Jacques,

    You’re just digging yourself in deeper:

    “not the precise equivalent of” is not the same as “not precisely analogous”.

    Thanks for explaining to me what a Feynman diagram is. That’s very helpful, and definitely raises the level of discussion here.

  • http://www.math.columbia.edu/~woit/blog Peter Woit

    And one should keep in mind that my last comment also crossed Jacques’s last in the aether.

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    Thanks guys. Don’t get me wrong – I think these discussions are great and I hope we’ll continue to have them. But there is a point where when it gets to “yes it is” vs “no it isn’t” a few times back and forth with no new information, and then it gets to “you don’t know what you’re talking about” vs “yes I do”. At that latter point -regardless who is right at that point, and I am not taking sides here on this discussion- I begin to worry that those young people who we thought might be put off from contributing to physics discussions on a blog for fear of being ridiculed (those same young folk we discussed on another thread, JD) might have their fears confirmed.

    So do keep up the valuable chat -take it to any level of detail you want to- but do try to let the facts argue for themselves. The informed reader will conclude for themselves who is right at that juncture, and the uninformed one will hopefully go away with the feeling that there is an interesting discussion going on and that physics is alive and well!

    Best,

    -cvj

  • Aaron Bergman

    I guess this is a good place to stop, then, especially because I feel that my previous comment #62 directly responds to Peter’s #65.

    (and, yet, 72 posts feels so short compared to my old Usenet days…..)

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    No, no! Carry on the thread if you want to. I was just trying to quell the flames on one particular strand. I believe there were other strands of interest, if people want to pick those up.

    For example. JoAnne injected a very useful ingredient, which resonates with Peter’s original remarks about the lack of experimental data in recent years to guide us. (Although that itself can be – and has been- argued). Anyway, JoAnne is optimisitic about the LHC producing tons of exciting stuff for us to get our teeth into. Anyone care to speculate about the LHC a bit? Maybe throw in some thoughts about what their “favourite” scenario for LHC physics might be and how it might fit with ideas we are looking at now? Vanilla Higgs? Doublet pointing to SUSY? No Higgs? Nothing at all leading to a new exciting crisis?

    Best,

    -cvj

  • Aaron Bergman

    Not having a particular dog in that fight, I’d like something that nobody has thought of, myself. I’m desperately afraid it’s going to be a single Higgs and nothing else, however.

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    Yes, that is a scary possibility. -cvj

  • http://dftuz.unizar.es/~rivero/research/ Alejandro Rivero

    Joanne, I hadn’t heard of this history about UA1 discovering SUSY… I will enjoy if you get some time to speak of it. It is specially amusing if the background was a tau. After all, if SUSY had been postulated back in the fifties, I can imagine the expectation about finding a charged fermion instead of a charged scalar in the 100 MeV range :-)

  • http://blogs.discovermagazine.com/cosmicvariance/joanne/ JoAnne

    Alejandro,

    I should blog about this sometime! UA1 (and UA2 as well, I think) had events with missing energy + jets. You can just imagine the number of theory papers that were written! Many of which announced the discovery of Supersymmetry, although the experiment(s) themselves made no such claim. (However, UA1 DID claim the discovery of a 40 GeV top-quark at one point!) At some point, legend has it that Altarelli stood up during a UA1 presentation at some meeting, and declared that in his opinion, the missing energy events were a combination of several different backgrounds, including production of the tau. This explanation became known as the `Altarelli Cocktail’ and eventually was shown to be correct via massive Monte Carlo studies. Note that the tau had not yet been observed at a hadron collider.

    This is one of the best arguments for the International Linear Collider that I can think of!

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    JoAnne,

    If supersymmetry is just around the corner, is the LHC really tuned to confirm it beyond reasonably doubt, or can it only hint at it and we’d have to wait for the Linear Collider. I think I’ve heard arguments both ways.

    Thoughts?

    -cvj

  • Moshe Rozali

    Clifford,

    More complete answer to follow, I am sure, but I recall for example the idea of bosonic SUSY (hep-ph/0205314). To distinguish this from real SUSY one would need information about spin, which apparently is difficult at the LHC.

    best,

    Moshe

  • Gordon Chalmers

    Why cant you write a computer program and test to multiple orders in the coupling to check even current data, and future data.

  • Gordon Chalmers

    Its possible now to make a computer program to test to hundreds of loops of a cross section on your laptop.

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    Moshe, that’s interesting indeed! I’d heard that even for “normal” MSSM-type scenarios that depending upon parameters there might be ways of hiding it very well from LHC. But I might not have understood the discussion properly. JoAnne will no doubt set us straight.

    -cvj

  • Gordon Chalmers

    Clifford,

    You dont want to comment on the possibility of many multi-loops on the laptop?

    Gordon

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    Gordon,

    I find myself unable to comment. I have nothing intelligent to say about it, so I figure saying nothing is best. Thanks for asking though!

    -cvj

  • Gordon Chalmers

    Do you think that it is worth a job in physics, Clifford?

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    Now I’m really confused. Relation to thread, please? -cvj

  • Gordon Chalmers

    The relation to the thread I thought was clear. Models are solvable, even on your laptop.

  • Gordon Chalmers

    It seems to me possible that if I solve QFT in general, then I can get a job, either in academia or industry.

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    I’d imagine it is possible, but I’m not an expert on employment matters. I’m going to move on from this now since I see no relation to the thread and clearly am not useful to you. Best, -cvj

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  • Moshe Rozali

    Clifford,

    What I find cute in this particular idea is not that SUSY is hidden, but that the optimistic scenario of finding lots of superpartners is in effect, though they are not superpartners really.

    best,

    Moshe

  • http://dftuz.unizar.es/7Erivero/research/ Alejandro Rivero

    Thanks for the hint, Joanne. I haven’t heard of the “Altarelli Cocktail”. I was aware of the preannouncement, in Nature, of a Top Quark because Tony Smith keeps track of every top-related problem in his website. The article was title “CERN again on top”, or something so.

    From your explanation I see that my small joke (that the tau can be perfectly a SUSY particle, if one wants to see the muon as susy to the charged pion) is unrelated to the UA* tales.

  • Gordon Chalmers

    Perhaps one should check the experimental
    data again on the values of the mass

    formula, i.e. for apparent information on
    particles. Because they could be specified,

    this check might be time and cost effective.

  • Gordon Chalmers

    Question to the experts: How much time would it take exisiting techniques to check the current public data for the existence of a potentially background smeared massive particle at 270 masses (give or take a hundred values)?

  • Gordon Chalmers

    Two anomalous bumps in data would probably be significant. Almost all publicly known particles fit that formula, with a similar uniform prediction at the next sub-leading order.

  • Gordon Chalmers

    I suppose if one could solve the theory to a 1000 loops or more then a better test could be made.

  • Anonymous

    Against my better judgement, out of late-night curiosity, I’ll bite: what are you talking about, Gordon? You seem to have a lot of papers on the arXiv suggesting that recursion relations and considerations of unitarity and analyticity allow perturbation series to be computed. Of course I’m willing to believe that, based on the work of Bern, Dixon, Kosower, and the others who’ve recently jumped on the twistor-inspired bandwagon. But it’s still hard work to figure out how to use these things, and if you really have a general algorithm, why hasn’t e.g. Bern (your old advisor, apparently?) started using it? Apologies to the owners of this blog — maybe Gordon should start his own blog to evangelize — but I’m somewhat curious about whether in the tens of papers he’s posted there might be some actually useful stuff.

  • http://dftuz.unizar.es/~rivero/research/ Alejandro Rivero

    There are some “tipo guadiana” running projects to put some order in loops using computational techniques. Check for instance Kreimer, who uses sometimes knot theory, sometimes Hopf algebras.

  • Gordon Chalmers

    Anonynmous

    I was referring to the apparent mass formula listed in the “Anthropic…” comments, and why somebody should check with a narrow microscope its possible values for unusual phenomena in data.

    The recursion theory work is actually quite useful, I believe. In order to demonstrate it, I am writing a computer program doing exactly what my papers spelled out in simple details; I will probably set surprisingly good benchmarks for laptop computing in quantum field computing. Furthermore, I am kind of optimistic to get somewhat closed form solutions to the coupling dependence of any scattering process and in most field theories, including those containing bare interactions which have higher dimensions.

    I cant explain why people dont use these arguably not new techniques, but perhaps as usual people dont always like to put in a lot of time that either they are unwilling or unable to spend on projects that seem relatively unknown. I really believe that the standards of computing will change in general, and that once the first computer program is finished this will be obvious. It is important enough that somebody should carry this line of work to its end.

  • http://www.starlarvae.org Heresiarch

    Sorry if I missed something, but I don’t see any reference to Lee Smolin’s notion of Comological Natural Selection as a nonteleological alternative to Intelligent Design when accounting for anthropic coincidences. Basically, he taps Darwinian logic to come up with a model of the evolution of universes in which physical constants that skew universes toward black hole production give those universes an adaptive advantage in the ensemble of universes. More at http://www.starlarvae.org/Star_Larvae_Cosmological_Natural_Selection.htm

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