# 2004 TopCites

The SPIRES database is used each year to produce a list of the most frequently cited papers in particle physics. This year’s list has appeared, although the usual annual discussion of the list from Michael Peskin still hasn’t yet. The trends I commented on last year in the 2003 list are even more pronounced this year.

The top ten most highly-cited papers in particle physics are now dominated by experimental results in astrophysics and cosmology with five papers in this category. Particle theory is represented by three large extra dimension papers from 1998 and 1999, and a single string theory paper, Maldacena’s 1997 article on AdS/CFT. The Maldacena paper is now the fourth most highly cited particle physics paper of all time, surpassed only by citations of the Review of Particle Properties, Weinberg’s 1967 paper, and the 1973 Kobayashi-Maskawa paper.

Even more so than last year, this data shows that particle theory and string theory flat-lined around 1999, with a historically unprecedented lack of much in the way of new ideas ever since. Among the top 50 papers, the only particle theory ones written since 1999 are a paper about pentaquarks by Jaffe and Wilczek from 2003 at number 20, the KKLT flux vacua paper at number 29 and a 2002 paper on pp waves at number 32.

How many more years of this will it take before leaders of the particle theory community are willing to publicly admit that there’s a problem and start a diiscussion about what can be done about it?

For some other interesting statistical data gathered from this database, check out the SPIRES playground.

One relatively recent idea that probably hasn’t fully shown up yet in the yearly citation counts is Witten’s late 2003 idea about relating gauge theory and the topological string in twistor space. While the idea of working in twistor space has lead to a lot new results about gauge theory amplitudes, Witten’s original hope of relating gauge theory and string theory seems to be in trouble.

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### 53 Responses to 2004 TopCites

Everyone would like to know what can be done about it. Of course, the right thing what to do about it is to discover new revolutionary ideas.
Do you know how to do it?

What about diff anomalies in 4D? At it should be new, since Weinberg (chapter 22) claims (correctly, within his axioms) that no such things exist.

But diffeomorphisms generate a gauge symmetry, and you have repeatedly stated that the right approach to gauge anomalies is ignorance. Just tell me one thing, though. How can you know that there is something special about the bosonic string in 26D if you don’t know about conformal (gauge) anomalies? Or, why is it ok to be ignorant about the quantum reps of the constraint algebra of GR, but not about the reps of the Virasoro algebra? After all, both GR and the bosonic string are constrained Hamiltonian systens.

2. Lubos Motl says:

I agree with Peter’s statistics.

As far as I know, everyone knows – and admits – that the high-energy theoretical physics is in a quiet period.

Everyone would like to know what can be done about it. Of course, the right thing what to do about it is to discover new revolutionary ideas.

Do you know how to do it? Let me just warn you in advance that the Dirac operator is not a revolutionary idea anymore. 😉

3. Hello,
I saw reference to a webpage of mine on Cosmology.
I think in your discussion of a career in Physics and the censorship inherent in the system, that the Internet is now changing all the rules for the evolution of cultural knowledge.
Plus there is a very simple sensible language for describing reality. I can’t imagine this being ignored for that long. So I think physics will blossom in next 20 years, along with philosophy.
Thoughts?
Geoff Haselhurst
http://www.spaceandmotion.com/contact-email.htm

4. Peter says:

I’m deleting the last few comments responding to Pedro about grad school and where particle physics is going since this discussion is getting both off-topic and there are some people who just can’t stop themselves from being hostile and obnoxious, others who find it hard to ignore them.

His question is a difficult and legitimate one. If people have some useful, non-hostile, advice about what the current situation means for people thinking about grad school in theoretical physics, go ahead and comment. But stop it with the obnoxious off-topic abuse.

5. quantoken says:

Petro:

You are going to have a miserable life with little achieved, if you want to get into the field of theoretical physics research. As the state it is it is unlikely going any where until something is changed. You can not afford to waste your life on a pursuit that every indications show it’s not going any where within your limited lifespan.

http://infoproc.blogspot.com/2004/12/dont-become-scientist.html

http://wuphys.wustl.edu/~katz/scientist.html

And this, too, to open your mind a bit:

http://www.suppressedscience.net

And this, to see what exile scientists are like:

http://www.spaceandmotion.com/Cosmology-Big-Bang-Theory.htm

It is completely possible to make a much easier and more comfortable living on something more connected to reality, while at the same time pursuit some interests in fundamental physics research, with total freedom of mind, like I do. Einstein was a very young (26) amateur “crackpotist” who barely graduated from college, and would be unable to publish anything on today’s ARXIV, when he made some of the greatest discovery in human history, within a period of just one year. Relatively, his professional career in his second half of lifetime achieved virtually nothing. See my blog:
http://quantoken.blogspot.com

Quantoken

6. Alan says:

I know that Peter W. is a stickler for keeping these discussion threads to the topic at hand (in this case, citation counts and whether they’re a valid measure of the intellectual vitality of ideas), although in this case he appears to have let the thread veer off in some other directions.

For Pedro, who inquired about directions to take in graduate training, I would highly recommend the “Academic and Career Guidance” board at http://physicsforums.com . A direct link to the academic board is:

http://physicsforums.com/forumdisplay.php?f=139

In particular, there was an interesting recent thread comparing different graduate schools:

7. Wolfgang says:

Pedro,

as Peter has pointed out on his blog several times before,
there are many interesting questions open in physics apart from quantum gravity or string theory.
If I were young, I would focus on those areas.

8. pedro says:

That is quite true – and by no means am I looking for a conciliation between competing approaches just for the sake of it. Rather, given the absence of significant empirical evidence towards either string theory or its ‘main’ competing theories and the fact these theories are, at the moment, incredibly open-ended; while at the same time, given the attractive ‘transempirical’ results/content of such theories, what are presently, if any, mathematically consistent and ‘physically sound’ alternatives to them (which could, perhaps, incorporate appealing elements of both fronts)? Or better, assuming there *is* a problem with current particle theory, *what* would be its tentative solutions? (either way, I grant you these are probably incredibly naive questions)

9. Wolfgang says:

Obviously I meant “view points” not “few points”

10. Wolfgang says:

Pedro,

I am afraid physics is not so much about “conciliate” different few points and rather about
finding and weeding out wrong assumptions and hypothesis.
The main tool to eliminate wrong ideas (experimental evidence) unfortuantely does not work so well due to the high energy scale at which quantum gravity becomes important. But this could change overnight if somebody discovers evidence in favor of one idea or the other.
I am afraid that there are no “safe bets” one way or another and I am afraid there is no good advice for you in this situation other than to work on ideas which may also apply to areas where empirical evidence is available …

11. Pedro says:

Hi,
I guess this is going to bring the tone of the current discussion down a bit; but since the ongoing argument seems to touch on something that has been bothering me for a while, thought of posting my concerns here.
I’m a physics undergraduate student, hopefully soon to embark on graduate studies, and, given the apparent polarisation of the ‘unified theory’ theoretical physics research into string theory and quantum gravity, I have to say I’m quite torn between which direction to follow.
Now, from my current quite limited perspective, it seems that both ‘areas’ are generally problematic: while a lot of the quantum gravity approaches (I’m thinking, slightly more specifically, of the ‘causal’ approaches) seem to provide a nice ‘intuitive’ picture/potential unification of QG and GR, say, they are still quite far (but I could be immensely wrong here!) from properly tackling the behaviour of particles and their interactions (I have the impression a lot of research is done on the structure of ’empty’ space-time only); string theory, on the other hand, while growing out of theoretical particle physics research and despite all its mathematical ‘triumphs’, not only paints a very odd picture of the universe, but is also a long way from connecting to current ‘experimental’ particle physics – is that the case? If so, is there any current research projects attempting to perhaps conciliate this polarisation?
Lastly, assuming your conclusion from the 2004 TopCites is correct, and there really is a big problem with current particle theory/string theory, what are the viable alternatives, or one candidate for an alternative be? (and this is a genuine question – I don’t mean to sound agressive).

12. Peter says:

Hi Wolfgang,

I agree with you that work on topological strings is the most interesting thing going on these days in string theory. Problem is, this is a case where people who say that string theory is “math, not physics” are right. There’s a lot of interesting mathematical work going on in this area, and if SPIRES also included pure math papers, maybe Vafa’s papers would get bumped up into the top 50.

I do disagree with you about 1990 though. At that time Witten’s Chern-Simons theory and TQFT stuff had just come out, things which I think are far more interesting both for math and for physics than the topological string ideas of recent years. Of course topological strings have their origin in precisely this work of Witten’s.

13. Anonymous says:

Regarding citations of the Weinberg’s ’67 paper, physicists did not know then if spontaneously broken YM theories were consistent or renormalizable; it was a ‘conjecture/belief’. Soon after ‘t Hooft (and Veltman)’s brilliant work on renormalizability of YM theories was understood (circa ’71/’72), the citations on the Weinberg paper naturally picked up.

14. Anonymous says:

“The NSF and DOE should stop giving grants to people who intend to pursue a dead idea that doesn’t work.”

Funding system works by innovating over ideas we known. The risk about calling for a “stop” is that there is no guarantee of getting funds for new ideas; just an increase of funds for the other old competing ideas.

An interesting system could be that each university had the right to claim a percentage tax on each group “justified research” funds in order to fund “unjustified research” of every tenured professors, without restriction. That should be a return to academic freedom and perhaps a way to get new ideas into the game.

15. wl says:

>
If either you or Matthew have a better objective measure for the number of new ideas coming out of particle theory that many people think are interesting enough to work on during a given period, let’s hear it. I think the one I have given is pretty meaningful, and agrees with the perceptions of most working theorists.
>

Well I do not agree. For example, the things that happen in topological strings right now are in my opinion totally fascinating and meaningful. And more so than eg 5 years ago – there has been lots of substantial progress in this field, in contrast to what you seem to convey.

That these papers do not collect as many citations as others, like those on flux compactifications, is quite irrelevant. For example, it reflects how many people are working in the field, how many are able to follow the subject and make contributions, how difficult it is to write papers in this given field.

These are all sociological factors and there are others, eg it is also matter of taste what people find interesting/promising/rewarding. So one cannot draw general conclusions such as yours, namely that string theory would be declining, from such crude data. On the contrary, I find it an especially interesting time, definitely much more interesting than eg around 1990. I remember having heard similar statements at the time, and indeed physics was pretty boring then in comparison to today.

16. DMS says:

“Well, Michael, …”

Oops, that was Mathew, not Michael. Sorry.

Well, I do not have a problem with phenomenological attempts, like the Little Higgs models, that can be tested/falsified. It is amazing how many models can be discarded from precision measurements, which is a good thing.

This is very different from “superstring phenomenology”, the TOE approach. Supposedly, a “unique” string theory leads to so many possibilities that it is not at all predictive. In what way is it more predictive than an arbitrary QFT, when it comes to being testable experimentally? The “bottom-up” approach is more meaningful when it comes to phenomenology, IMO.

But I think there is no compelling reason to believe any of these models are correct (unlike say GIM which predicted existence of charm and even a rough estimate of its mass based on Gaillard-Lee (?)’s famous calculation).

17. Peter says:

Hi Wolfgang and Matthew,

I often say things on this weblog that I know relatively few people in the field agree with me about, but I’m finding it strange that you object to this posting, because I don’t think the point I am making is controversial at all among working particle theorists. Without exception, everyone in the field I’ve discussed this with privately in recent years, string theorist or non-string theorist, feels that the last few years has been a period of unusually few interesting new ideas. It’s true that I mostly talk to more mathematically-minded theorists, perhaps more phenomenologically-minded ones don’t so much feel this way.

For Matthew:

I guess you’ve only been working in this area for a few years, so I don’t think you have first-hand experience about what the particle theory research environment was like 10,15,20,25 years ago and how different things were then. I encourage you to ask your more senior colleagues how they see the activity of the last five years as compared with earlier periods in their careers, especially consulting any string theorists you may know.

I also looked at the 94-96 topcite data, found 3 theory papers in the top 10, (4 in the top 11), and 12 in the top 50 (I think you missed Hull and Townsend, one Isgur-Wise, and a parton model paper). I think that it is undeniable that

1. 0 is less than 3 (number of papers in top 10)

2. 3 is less than 12 (number of papers in top 50)

and that these differences are statistically significant.

I’m not going to waste my time anymore today trying to get you to distinguish the difference between the way you’re using the word “prediction” and the way most scientists in the world understand it.

Wolfgang,

The list I linked to orders papers by how often they were cited during 2004. For a paper to be in the top 50, it would have to have been cited by 155 or more papers written during 2004. None of Vafa’s papers satisfy that criterion.

If either you or Matthew have a better objective measure for the number of new ideas coming out of particle theory that many people think are interesting enough to work on during a given period, let’s hear it. I think the one I have given is pretty meaningful, and agrees with the perceptions of most working theorists.

18. DMS says:

Well, Michael, Peter has answered the “predictive” aspect of the brane models better than I could have. I suppose it depends what the meaning of the word “prediction” is; I am old-fashioned in that regard.

On the Little Higgs models, (according to hep-ph/0502066), the initial hope that such models (at the least the popular ones) have less fine-tuning than the MSSM (already needing fine-tuning at 2% level) from precision electroweak constraints, may not be valid.

19. Matthew says:

Hi Peter,

I don’t doubt you can find papers about brane models containing the word “prediction”, but I do doubt you can find an actual prediction in any of them.

The paper I cited has acutal predictions in it.

None of these models is capable of making a real prediction that could falsify the brane world idea. For one thing, the energy scale of these things is completely undetermined (other than that it better be big enough so that you wouldn’t already have seen something).

Well, I think technically this is true. But from a model building perspective, it’s not. You construct a model to solve certain problems. If the energy scale is too low, then it’s already rule out. If it’s too high, then you no longer solve the problem you set out to solve.

What a legitimate “superstring phenomenology” should do is tell us what the size and properties of the brane will be.

Well, that would be nice, but since the string theorists haven’t delivered said predictions yet us “mere mortals” build models.

The papers you quote are more along the same lines. They say something like: if we choose a Little Higgs Model with properties A, B, C, it has a particle X whose mass we know nothing about other than that it better not be too large (and we don’t really know exactly what too large means).

Not quite. They say if I build a model with these parameter/this structure then it predicts X. Now of course you can change the parameters, but that’s true of *any* model. Some models allow more flexibility on this point than others.

As you note, it is very hard to figure out how to distinguish such a model from anything else.

So we should not build models at all? Look, part of the problem of distinguishing models is because the LHC is a messy hadron collider. Since we can’t change that, we make do as best we can.

Does any Little Higgs model actually predict the mass of anything?

Sure, pick the parameters, and the model is predictive. Not unlike the standard model. The second little higgs paper I linked has a plot of the new spectrum, for a certian choice.

I wasn’t saying that there are fewer particle theory papers these days than ten years ago, I was saying there are many fewer that people think are worth citing. This indicates there are virtually no new (good) ideas coming out of the field.

And this is where I disagree. You’re linking citations with “new ideas” is wrong. Nobody cited Weinberg’s 67 paper for several (5?) years. Yet it was a good idea.

Look at the SPIRES topcites list of ten years ago, and you’ll see lots of recent theoretical papers,

Okay, I did. The 94-96 top 50 list has 9 theory papers published from 1990 on. Two (Amaldi, Langacker) have do do with LEP, two (Isgur, Georgi) with heavy quark effective theory and one (Lepage and Mackenzie) with lattice field theory. Of the other four, two are Seiberg and Witten, one is Witten by himself, and one is Polchinski. Safe to say, this is not a hive of new ideas of what’s just beyond the standard model.

20. wl says:

What’s the logic of that spires list ? I know many famous papers
which have hundreds of citations, in particular have more citations than certain
papers which do appear in the list and which even are more recent. Eg do in Spires
http://www.slac.stanford.edu/spires/find/hep/www?rawcmd=find+a+vafa&FORMAT=wwwcitesummary&SEQUENCE=
however not a single paper of Cumrun’s appears in the list you cite.

I don’t see how any conclusion, esp on an alledged “flatness” of how string theory evolves, can be drawn from this.

21. Quantoken says:

Peter,

Thanks for providing the URL to the paper you wrote several years ago. It is because of honest people like you, rare nowadays but still exist in the science research community, who are brave enough to speak out the truth, that the public can still maintain SOME confidence in science.

No need to pay attention to Michael, who as DRL put it best, is just “pissing in the wind”. Some of his comments are worse than vulgarity. Shame for him that his “It just doesn’t suit you well” comment kind of tried to intimidate you to shut up and mind your own business and stop criticize string theory, or else. It’s not the kind of language an educated person will utter.

You comment of cutting funding is right on the spot! One has got to understand scientific researches are funded by tax moneys from the general public, and therefore it should serve the interests of the wellbeing of the public only. How much longer should the public continue to allow their tax money to be wasted on such totally fruitless pursuit?

Cut the damn funding now! String theoretists certainly are totally free to continue their fruitless pursuits, but on their own money, not the public’s money. Or, like Lee Smolin did, go talk to some rich guy and convince him that your theory makes sense to him, so he can fund you.

Frankly I think the LHC project now is just a waste of money. Since no one is willing to make any definite prediction beforehand. And you are all waiting for the machine to start running, and then you can outfit your theory with whatever comes out of it. So at the end of day your theory will still be un-falsifiable but still useless and unable to make predictions. What is the use of experiments if it can not help falsify some of the theories and confirm some others?

Quantoken

22. Aaron says:

To Peter — If they don’t find SUSY at the LHC, a lot of people will give up on weak scale SUSY definitely. Not because of fine tuning, but because if it’s not there to stabilize the weak scale or to unify the couplings or provide a dark matter candidate, there’s not much reason for it to be down there at all. High scale SUSY is what it is, but it’s not particularly of experimental import.

To JC — The MSSM is actually a very pretty exercise. The reason people got excited about it wasn’t because it was some slavish following of stringy fashion. It stabilized the weak scale, it provided a natural mechanism for electroweak susy breaking and it seemed to unify the couplings. There were good reasons to call it the best candidate for an extension to the standard model (other than neutrino masses). The problems really come when you break the supersymmetry. It’s the effective lagrangian for the broken susy that has the 109 or whatever parameters that people always refer to when denigrating susy. But those aren’t free parameters; they just depend on an undetermined model for breaking the supersymmetry. That’s where things start to get ugly.

Split supersymmetry is pretty straightforward, at the cost of some major fine tuning (which Nima and co would like to attribute to some anthropic hand waviness). You just break susy at some high scale. Thus, most of the SUSY partners are very massive, resolving all the difficulties with FCNCs, proton decay and the like. Then, you have the gluinos be at the weak scale. Since they’re chiral, this is technically natural (but not plain old natural). They give you some nice dark matter candidates and unify the couplings. Assuming I got all the details right, at least.

To Tom — you can have nonconformal stuff in AdS/CFT (oxymoronic, I know.) The most famous example of this is the Klebanov-Strassler solution, hep-th/0007191.

23. TripleIntegral says:

In re: the post’s comments on leadership from the top particle theorist community, it seems to me that in his public statments Witten has at least recently been fairly honest about hopes for string [whatever] theory and its accomplishments and prospects. Others less so. For example, Susskind seems to be his own type of legacy-enhancing pathology. The small fry need someone’s skirts to hide behind and crumbs to lick off the floor. Thus has it always been.

24. JC says:

Split SUSY and some of the SUSY models beyond MSSM, sure seem like the equivalent of “Rube Goldberg” machines in the particle phenomenology world.

AdS/CFT is interesting because it holds out some hope of producing strng theory duals to 4d QFTs you care about, like QCD.

My point was that dS/non-C QFT would be a lot more interesting duality, since it might have something to do with the real world. AFAIK, QCD is not conformal, although classical chromodynamics is.

PS. When I said that Nair was a string theorist, I might have confused him with Narain.

PPS. This is my first night with broadband. My oldest daugther has just reached the Internet chat age, and the telephone bills started to become scary.

26. Peter says:

What’s the gluino mass bound? Is it within the reach of the LHC?

If the LHC really could rule out split supersymmetry, as well as regular supersymmetry since the fine-tuning required is implausible, will people really give up on supersymmetry for good?

27. Aaron says:

Split supersymmetry was born out of anthropic nonsense, but by itself, it’s just a fine-tuned model that has some straightforward signatures. Split supersymmetry has most of the fermionic partners to avoid issues with FCNCs, proton decay and the like. It has the gluinos (IIRC) light, however, so as to give coupling constant unification. You either see that or you don’t. If you don’t, split supersymmetry’s wrong. Simple as that.

28. Peter says:

Isn’t split supersymmetry even less predictive than standard ideas about supersymmetry? Supersymmetry was supposed to eliminate the need to fine-tune the Higgs mass, which meant that superpartners couldn’t be too massive.

In split supersymmetry, you decide to throw out the main motivation for supersymmetry and trust in God or the anthropic principle to explain why the Higgs is so light. The only thing you’re left with is the (not quite accurate…) coupling constant unification. Perhaps if you want to keep this you get some constraint on how heavy your fermionic superpartners can be, but this is a long way from a definite prediction of anything.

29. Aaron says:

Split supersymmetry, at least, is a predictive fine-tuned model. If they turn on LHC and don’t see what it predicts, it’s dead. Coupling unification is a assumption of the model, and thus you need some lightish fermions to achieve it.

30. Peter says:

Hi Matthew,

First of all, just saw your response to DMS. I don’t doubt you can find papers about brane models containing the word “prediction”, but I do doubt you can find an actual prediction in any of them. None of these models is capable of making a real prediction that could falsify the brane world idea. For one thing, the energy scale of these things is completely undetermined (other than that it better be big enough so that you wouldn’t already have seen something). Saying that “if there’s a brane with this size and these properties I predict the LHC will see X” completely begs the question. What a legitimate “superstring phenomenology” should do is tell us what the size and properties of the brane will be.

And by the way, I (and I suspect many other people here) do read hep-ph.

The papers you quote are more along the same lines. They say something like: if we choose a Little Higgs Model with properties A, B, C, it has a particle X whose mass we know nothing about other than that it better not be too large (and we don’t really know exactly what too large means). The problem with this is that you can get an extremely wide range of different things by changing A,B,C and choosing all the undetermined parameters and masses. As you note, it is very hard to figure out how to distinguish such a model from anything else. I said none of these classes of models give a “definite picture” of what will happen at the LHC and I stick by that. By a definite picture, I mean something like actually predicting the mass of a particle. Does any Little Higgs model actually predict the mass of anything?

I wasn’t saying that there are fewer particle theory papers these days than ten years ago, I was saying there are many fewer that people think are worth citing. This indicates there are virtually no new (good) ideas coming out of the field. I don’t think it is at all helpful to try and deny this in face of strong evidence. Look at the SPIRES topcites list of ten years ago, and you’ll see lots of recent theoretical papers, few of which have anything to do with LEP data. The difference then was that people were still regularly coming up with new ideas about string theory that other people thought were promising enough to work on and to cite. This has stopped happening.

31. rob says:

There is one factor that has been overlooked. Spires has recently added the astro-ph to it’s collection of papers. It is not surprising that all those astronomy papers cause cosmology papers to have a higher number of citations than they had in the past.

32. Matthew says:

DMS

Do you (or anybody else here) actually read hep-ph?

I know enough about the superstring “phenomenology” (like the wonderful brane “models”) to know that they are not useful for particle pheonomenology and definitely not predictive.

The very first paper returned on a hep-ph abstract search for “collider brane” is hep-ph/0502031,

“In the context of an universal extra-dimensional scenario, we consider production of the first Kaluza-Klein electron positron pair in an $e^+e^-$ collider as a case-study for the future International Linear Collider. The Kaluza-Klein electron decays into a nearly degenerate Kaluza-Klein photon and a standard electron, the former carrying away missing energy. The Kaluza-Klein electron and photon states are heavy with their masses around the inverse radius of compactification, and their splitting is controlled by radiative corrections originating from bulk and brane-localised interactions. We look for the signal event $e^+e^- +$ large missing energy for $\sqrt s = 1$ TeV and observe that with a few hundred fb$^{-1}$ luminosity the signal will be hard to miss since standard model backgrounds remain well within control. We also comment on how this signal can be distinguished from similar events from supersymmetry.”

My simple search pulled down 78 hits, with some more work I’d bet you can find over hundred papers on the predictions of various brane models.

33. Matthew says:

Hi Peter,

If you look at the SPIRES topcites data from ten years ago, you can see that things were very different than now

Yes, things were very different, LEP was new and taking data. There was experimental data to work with. I’m not arguing that the number of theory papers isn’t down, just that this represents a problem. I’m much more inclined to think that this will be par for the course in the era where there is one experiment at the cutting edge at any one time.

It’s not a problem though, when the LHC turns on, balence will be restored 🙂

Also, one has to couple in the massive amount of cosmology growth in the past ten years. That’s a whole new set of papers that impact HEP citiations in a new way.

The new ideas you mention, like split supersymmetry, aren’t getting a lot of citations because they aren’t very promising.

There no more or less promising than any other new idea. That’s the point.

They don’t really explain any known experimental result

Sure they do. Most of them explain why the Higgs mass is not at the planck scale. Others attempt to explain the ferimon mass hierarchy. Now you might not think that the explanations given are good or sensible, but that’s a different arguement.

or give definite predictions about what future accelerators will see

Sure they do. Some of the people here are engaged in making these predictions. Indeed, it’s an active field of research trying to figure out what one should look for in order to distinguish different models, many predict very similar signals at the LHC.

If one of these ideas actually gave a definite picture of what will happen at the LHC, it would attract a huge amount of attention and number of citations.

Again, this is simply untrue. Any model builder worth his or her salt will give a picture of what will happen at the LHC (the level of detail depends on the model builder). For example hep-ph/0402037,

“We discuss possible searches for the new particles predicted by Little Higgs Models at the LHC. By using a simulation of the ATLAS detector, we demonstrate how the predicted quark, gauge bosons and additional Higgs bosons can be found and estimate the mass range over which their properties can be constrained.”

or, to highlight some colleagues, hep-ph/0411264,

“We begin the study of the LHC phenomenology of the littlest Higgs model with T-parity. We find that the model offers an interesting collider signature that has a generic missing energy signal which could “fake” SUSY at the LHC.”

Work like this appears for all sorts of models, the collider phenomenology of the MSSM, for example, is worked out in massive amounts of detail.

I think phenomenologists are in a very tough spot and will be for at least the next few years, through no fault of their own. I don’t think there is much that can be done about this until there’s new experimental data.

My own observations are different. Phenomenology has been getting more active over the last few years. The difference between when I started as a grad student, and now, is clear. There are more new ideas, and more people exploring them.

34. Peter says:

Hi Thomas,

AdS/CFT is interesting because it holds out some hope of producing strng theory duals to 4d QFTs you care about, like QCD. So, if you’re a bit optimistic, it may help you solve QCD. But it has really nothing at all of any use to say about the idea of an 10/11 d string/M theory TOE.

Anyway, your case it not convincing. String theory has evolved in phases, often referred to as “string revolutions”. I’m not sure if Maldacena’s ADS/CFT qualifies as a revolution, but I perceived it as one.

I find the enormous interest in AdS/CFT somewhat curious, since I thought that both AdS (negative cosmological constant) and CFT (absense of massive particles) were ruled out experimentally. And in order to establish the connection between these experimentally falsified ideas, you probably need SUSY, which itself has a lot of problems with observation (or lack thereof). But perhaps I’m just old-fashioned to believe that physics has anything to do with nature…

36. DMS says:

Michael,

Although I do not understand D’Hoker-Phong’s brilliant achievements, I know enough about the superstring “phenomenology” (like the wonderful brane “models”) to know that they are not useful for particle pheonomenology and definitely not predictive.

It may be sufficient for you what the “experts” say/think, it is not sufficient for me.

37. Peter says:

Hi Michael,

I’ve exchanged e-mail with Witten about this, so know exactly what his circumstantial evidence is, and think it is extremely weak. I have an incredible amount of respect for Witten, both for his talents and for his accomplishments. By far the best argument for string theory is that he believes it, but I happen to think he’s wrong about this. What’s superstitious is to just accept what someone says without evaluating the evidence for yourself.

What you quote Maldacena as saying was actually said by Seiberg. I don’t think joking about how arrogant you are is really “self-criticism”. Far too many string theorists are incredibly arrogant, and while some of them would admit this I don’t notice any of them thinking there is anything wrong with it.

38. Peter says:

Hi Matthew,

First of all, I think there’s a straightforward objective issue here: when was the last year in which, if you put together a list of the 50 most heavily cited particle theory papers, only a couple would date from the last five years? I’m pretty sure you would have to go back to around 1945, when WWII interrupted research for about 5 years. I don’t know much about what things were like in the earlier part of the century, but I suspect you might have to go back to the 19th century to find another year in which this happened. If you look at the SPIRES topcites data from ten years ago, you can see that things were very different than now, and if anyone knows of a source of similar data from earlier periods I’d be interested to hear about it. Particle theory is in a new situation, quite unlike any other one of the modern period, and people should be thinking about what this means.

The new ideas you mention, like split supersymmetry, aren’t getting a lot of citations because they aren’t very promising. They don’t really explain any known experimental result, or give definite predictions about what future accelerators will see. If one of these ideas actually gave a definite picture of what will happen at the LHC, it would attract a huge amount of attention and number of citations.

As I mentioned in a previous comment, I think phenomenologists are in a very tough spot and will be for at least the next few years, through no fault of their own. I don’t think there is much that can be done about this until there’s new experimental data. Whatever overhyping of ideas that is going on amongst phenomenologists is relatively harmless.

String theory is a very different story….

39. Michael says:

Hi Peter,

what you say sounds reasonable under the assumption that string theory is not worth pursuing. This assumption is what’s in question, and I submit to you that it may not be for you to decide. The big figures in string theory have a lot better grip on this than you do. If you listen to them, they are very reasonable and smart people who do not rush to any conclusion — like you do.

Witten for example states that it’s his personal opinion that there is circumstatial evidence that string theory is on the right track. How could you possibly argue with this without being superstitious? Let me tell you: you can’t.

Maldacena says that string theorists are arrogant enough that whatever comes up in their research, they will call it string theory.

So you can see that these people show a measured amount of self-critcism. At the same time they are the ones who do prove that string theory *is* worth pursuing, even if we can’t be sure at this point what it’s relation to nature is.

You have absolutely nothing to add to this. Can you be honest enough to admit it?

Your claims of intimidation and such are unsubstantiated and wrong. You have no evidence and you just make up such things because you know that in the absence of such claims your authority in this matter drops to it’s true value, namely zero.

Do you find it attractive to sit in one boat with crackpots like quantoken (see quantoken.blogspot.com, if you have the stomach for it)? You have learned a number of serious things in math and you can make your little contribution to this field. Why waste it and bark with the crackpots instead?

Best, Michael

PS: DMS, you know enough string theory to arrive at a conclusion that is completely inconsistent with that of the experts in the field? Who are you kidding?

40. D R Lunsford says:

Michael – I’ve read your betters, and what you say is just a lot of pissing in the wind. I’m sure it suits the postmodern intellectual Narcissus in you, but you aren’t fooling anyone.

-drl

41. DMS says:

Michael,

I know enough physics to know string theory is highly over-hyped. All papers on “string phenomenology” are total, pure, unadulterated garbage. The people practising it know little about precision electroweak physics. It has made *zero* predictions: no, consistency with anything is not a wonderful thing.

Of course, some of the mathematical work is very valuable, but that is a very small portion.

It also does not help when people practising string theory start bullying and throwing insults at people who point out the obvious.

So far, the paying public has a pretty high regard and respect for physics and physicists. But it will not take much (a couple of “landscape” books?) before they catch on to the gimmicks, and unfairly lump theoretical physics with some other fields, like climate science.

42. D R Lunsford says:

It was clear since “An Evaluation” that what you are doing is rather heroic, and it is just great to have someone with the balls to tell the truth on the planet.

-drl

43. Peter says:

Hi Michael,

I’d be much happier not to be spending my time doing this, but the problem is that no one else is. A lot of people are out there hyping the glories of string theory, but virtually no one who understands the theory has been willing to publicly criticize what is going on. Several people who agree with me have told me they won’t do this because they fear retribution: string theorists are on the panels deciding whether they get a grant and whether their students get jobs. There’s a really ugly atmosphere of intimidation going on here, including nasty personal attacks from people like you, Motl, Distler, and others on anyone who dares to criticize the string theory hype.

The people who should be doing something about what is going on, tenured people at major research institutions, for one reason or another aren’t doing it. When they start, I’ll shut up.

44. Peter says:

Hi Kyle,

I’ve addressed this in various places, including the first public thing I wrote on the subject four years ago:

http://www.arxiv.org/abs/physics/0102051

Here’s a summary of what I think needs to be done:

1. Publicly admit the problem. As long as leaders of the field go around giving talks and writing books about how well things are going, no one is going to be willing to change anything.

2. Publicly admit that the idea of string theory as a TOE is a failure and needs to be buried. More phenomenologically motivated approaches to particle theory are in trouble because of the lack of new data, and unless the Tevatron or someone else comes up with something unexpected, this situation will last until 2008, when maybe the LHC will change things. But more mathematically driven “top-down” research still has a chance of getting somewhere. Some radical new ideas are needed, but as long as it is extremely difficult to get a job doing mathematically oriented stuff unless you are doing string theory, hardly anyone is going to be working on this.

3. The NSF and DOE should stop giving grants to people who intend to pursue a dead idea that doesn’t work. Once the community admits the problem, the NSF and DOE could play a role in promoting funding of proposals to try something new and different, discouraging funding of proposals to do the same old thing. As long as it is very hard to get a grant or a job working on mathematically sophisticated approaches to particle theory unless you are doing string theory, nothing is going to change.

What has been going on for far too long is that bright young people who come into the field end up spending years of their lives mastering the intricacies of string theory. They end up not knowing enough to do anything ambitious that isn’t string theory, and the reward system is such that even if they wanted to try they would soon be without a job. People have to think about how to change this reward structure. It’s not going to change until the underlying problem is acknowledged.

45. Matthew says:

My comment got a little long, so I posted a short response on my blog. In short, Peter, you’re wrong 🙂 Number of citations does not correlate with number of new ideas. Particle theory is acutally pretty active these days.

46. Michael says:

Hi Peter,

Sorry if I offended you too much. I didn’t mean to be what you called me.

Anyway, your case it not convincing. String theory has evolved in phases, often referred to as “string revolutions”. I’m not sure if Maldacena’s ADS/CFT qualifies as a revolution, but I perceived it as one. Understanding gauge theory using gravity and vice versa is extremely exciting if you keep in mind that gauge theories are proven to describe nature and gravity is what we need to understand better.

Are you worried about no more such major steps forward in the last 6 years? I doubt it. For one, your critisism has been around for several years, so you didn’t wait until nothing terrific had happened in 6 years. Also the time period between the string revolutions in the past was typically longer than that. The next may be just around the corner, and what are you going to say when it comes?

Peter, you are more outspoken about string theory than people like Ed Witten and Juan Maldacena. It just doesn’t suit you well. It is not humble and it is not honest on your part. You could earn a lot more respect by doing a good job at Columbia in the position you hold, talking about the things you do understand. Do you crave attention and publicity so much, even if it’s negative one?

Best,
Michael

47. Peter says:

Hi Michael,

I just presented some definitive evidence that string theory is intellectually dead. Instead of addressing this evidence all you can do is attack me personally. This is just pathetic.

Guess what? I’m not going to “knock it off”, no matter how many assholes like you I have to deal with.

48. Alejandro Rivero says:

I like to see Randall-Sundrum work (and Nima’s, and Antoniadis 1990 &c.) there in the top. It was clearly a provocative idea already back five years ago, and thinking pentadimensional is a funny thing, even if it is to go back to our beloved 3+1 dimensions Or 3+1+0 for a Connesian as I am.

It is funny that while the WMAP (what about the old presunt fractal behaviours, now?) replaces neutrinos in the top ten, the more quiet oscillation research has brough back a couple works of the past, Cabibbo 1963 and Maki, Nakagawa, Sakata 1962.

49. Michael says:

I know why string theory is in trouble! It’s because string theorists haven’t paid enough attention to the Woitian off-diagonal SU(2) embedding. Ignoring this crucial concept dooms any project in theoretical physics.

Knock it off, Peter, will you?! Your criticism is lame and repetitive.

I understand you must have dreamt of becoming a brilliant theorist until you found out that you are not capable of that. I know it hurts, but bitching about other people’s work for the rest of your life won’t help it.

Best wishes,
Michael

50. Kyle says:

(sorry, I was refering to the scentence that ends “admit that there’s a problem and start a diiscussion about what can be done about it?” in my comment below)