Causes of loss of interest in String program

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suprised said:
marcus, your claims are completely absurd, again...
:biggrin:
What are my claims? And why are they absurd?

BTW I liked some of the things you said in that other thread. Essentially I'm just groping around trying to make sense of what you (and a few others) said.

Let's look at your first four "wrong turns" and try to figure out how they could be fixed---so the core String unification program could get back on track. I will fetch them.

===quote Suprised post #553===
I guess there were many potentially wrong turns - at least in the sense of bias towards certain ways of thinking about string theory. Here a partial list of traditional ideas/beliefs/claims that have their merits but that potentially did great damage by providing misleading intuition:

  1. - That geometric compactification of a higher dimensional theory is a good way to think about the string parameter space
  2. - That perturbative quantum and supergravity approximations are a good way to understand string theory
  3. - That strings predict susy, or have an intrinsic relation to it (in space-time)
  4. - That strings need to compactify first on a CY space and then susy is further broken. That's basically a toy model but tends to be confused with the real thing.
...
==endquote==
 
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Suprised, you are in charge of how we interpret your words, so please correct me if I misinterpret. It seems to me that you provide a glimpse of renewal or "Renaissance" in the String program---which so far has very interesting math but no one definite physical theory.

1. We should stop thinking of compactified extra dimensions as real. The world is 4D.

3. String has no intrinsic relation to SUSY. We should cut loose from the SUSY dream and not waste so much research on "superstuff"

2. That goes for SUGRA ("supergravity") too. Supergravity approximations are not a good way to understand String.

2. continued...Furthermore perturbative is not a good way. Perturbative uses a fixed prior setup---including a prior geometry---which is then subjected to small variations. You regard this approach as deficient.

4. And Calabi-Yau is not the real thing. You warn against confusing it with reality.

To me this seems like a breath of fresh air, a hint of some kind of reconsideration taking place at the administrative level. For some reason I think of you as talking with Hermann Nicolai occasionally, one of the directors at Potsdam. If you know him, do you think he might agree with your assessment of program-damaging "wrong turns" and your ideas of a new direction?
 
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marcus said:
BTW I think you are wrong in classifying geometric Langlands as String. I attended three lectures by Witten on that a few years ago where String was not mentioned. It's high level mathematics with broad general applicability. Would you say that harmonic analysis was stringy?

It was one Langlands paper, http://arxiv.org/abs/arXiv:0802.0999, that was classified as string:

Mirror Symmetry, Hitchin's Equations, And Langlands Duality
Edward Witten
(Submitted on 7 Feb 2008)

Geometric Langlands duality can be understood from statements of mirror symmetry that can be formulated in purely topological terms for an oriented two-manifold $C$. But understanding these statements is extremely difficult without picking a complex structure on $C$ and using Hitchin's equations. We sketch the essential statements both for the ``unramified'' case that $C$ is a compact oriented two-manifold without boundary, and the ``ramified'' case that one allows punctures. We also give a few indications of why a more precise description requires a starting point in four-dimensional gauge theory.

Do you propose that 2d mirror symmetry is something other than string theory? I believe that I assigned all of the other Langlands papers to qft. My assignments were actually conservative, since if I had used the keyword "string" many of the qft papers I assigned come up as string.

I don't find your analysis convincing, or transparent/replicable. So I prefer to stick with the classification by DESY librarians. Does anyone accuse them of bias?

It takes about 10 minutes to look over the list of papers. I suppose it requires some knowledge to understand the papers, but I faith that you could replicate the analysis.

As for DESY librarians, I am not accusing them of bias, I am explaining that keyword searches are no substitute for actually knowing what is in the papers. Here is your list of 2003-2006 "string" papers: http://www-library.desy.de/cgi-bin/spiface/find/hep/www?rawcmd=find+a+witten+and+%28dk+string+model+or+dk+membrane+model%29+and+date+%3E+2002+and+date+%3C+2007&FORMAT=WWW&SEQUENCE=
Here is the list of all papers by Witten over that period: http://inspirebeta.net/search?ln=en...n_search=Search&sf=&so=d&rm=&rg=25&sc=0&of=hb

Some string papers that are not picked up by your search:

Two-dimensional models with (0,2) supersymmetry: Perturbative aspects.

The Hitchin functionals and the topological B-model at one loop.

Perturbative gauge theory as a string theory in twistor space.

This is not a comprehensive list, but serves to show how useless keyword searches are.



Thanks for having a look at those citation numbers! I am glad you agree with at least one of my conclusions "fewer ground-breaking".
I think you are wrong about "fewer...[String]...papers being written..."
I have tried to measure the gross output of research and have found it STEADY.

You have not quantified this. In Witten's case he has produced half as many papers in the last 3 years as he did over the prior 3 year period. You have not bothered at all to compare your keyword search results to total output for the named researchers. Interesting things can probably be learned from correct statistics.

But more and more of it seems not to interest other string theorists. It's hard to describe without sounding snobbish...more and more seems to come from people I have never heard of at institutions not of first rank on topics which are yet another variation on same old stuff. As you say, not ground-breaking. That is just a frankly subjective impression. However it is born out by the decline in cites.

This is a very narrow-minded and unscientific conclusion. Every field has a certain amount of unilluminating work produced by "people I have never heard of at institutions not of first rank on topics which are yet another variation on same old stuff." Just by the mere fact that you're using databases of work that has not been peer-reviewed makes this a bigger problem than you realize. The effect of these low-grade papers will go down a bit if you place some cuts on papers that have not been published. This is another reason why no-thought analysis has big problems when it comes to statistics.

I would say that in gross terms world wide (including China, India, etc...) String output is probably about steady, but there is a change in quality which is hard to put one's finger on.

It gets easier when you understand the subject that the papers are about.
 
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Hi fzero, you said total output had declined and I replied that I had tried to gauge it and found it approximately STEADY. I was using Harvard Abstracts for that. i think they already restrict to peer-review published stuff.

fzero said:
Just by the mere fact that you're using databases of work that has not been peer-reviewed makes this a bigger problem than you realize. The effect of these low-grade papers will go down a bit if you place some cuts on papers that have not been published. This is another reason why no-thought analysis has big problems when it comes to statistics.
...

It doesn't really matter. Show me some evidence that peer-reviewed string research output has declined over the past 10 years and I will believe you.
===============

You came up with a handful of Witten papers that you think should be included in the 2003-2006 count. What I'm looking for is a trend in what I should perhaps call DKSM papers, for "DESY keyword string and membrane".

Here are the DKSM numbers for Witten, Strominger, Maldacena, Polchinski, Harvey, looking for a trend. I don't suggest an interpretation of the trend, at this point (although you can) I am just looking to see if it shows up.

Code: 
          1995-1998      1999-2002      2003-2006      2007-2010
Witten         38             29              9              5
Strominger     23             14             22              4
Maldacena      27             33             24              9 
Polchinski     21             17             11              4
Harvey, J      16             15              9              2
If you want to stick in non-DKSM papers to the 2003-2006 basket then to be consistent you have to do the same thing to the 1995-1998 basket. It might increase even more! I doubt that what you are talking about would make any difference to the overall downtrend.

I think we agree that there has been a decline in ground-breaking papers.

I'm interested in the reasons for this which Suprised and others brought up in the "really disappointed" thread. Basically some physical misconceptions which have governed the way people in the program think.

I'm interested in what can be done about that.

The indicators that there has been a decline (in citations, in work by the best people, in "ground-breaking") don't really matter. Let's get back to the main topic of WHY, and what can be done.
 
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marcus, do you think ground-breaking work can really be "managed"? Discoveries are made in many ways, both by sudden revolutions as well as by slow steady work, and everything in between.

So whether you think any of these revolutionary or small increments - string remains the first field of study for anyone interested in quantum gravity:
1)integrability in AdS/CFT
2)ABJM
3)twistors
4)many, many standard model like constructions
 
marcus said:
===============

You came up with a handful of Witten papers that you think should be included in the 2003-2006 count. What I'm looking for is a trend in what I should perhaps call DKSM papers, for "DESY keyword string and membrane".

Here are the DKSM numbers for Witten, Strominger, Maldacena, Polchinski, Harvey, looking for a trend. I don't suggest an interpretation of the trend, at this point (although you can) I am just looking to see if it shows up.

Code: 
          1995-1998      1999-2002      2003-2006      2007-2010
Witten         38             29              9              5
Strominger     23             14             22              4
Maldacena      27             33             24              9 
Polchinski     21             17             11              4
Harvey, J      16             15              9              2


If you want to stick in non-DKSM papers to the 2003-2006 basket then to be consistent you have to do the same thing to the 1995-1998 basket. It might increase even more! I doubt that what you are talking about would make any difference to the overall downtrend.

You are still not getting it. The DESY keyword searches are deeply flawed and it isn't just about a handful of Witten papers. Here is your search for Polchinski 2007-2010:

http://www-library.desy.de/cgi-bin/spiface/find/hep/www?rawcmd=FIND+A+polchinski+AND+%28DK+STRING+MODEL+OR+DK+MEMBRANE+MODEL%29+AND+DATE+%3E+2006+AND+DATE+%3C+2011&FORMAT=www&SEQUENCE=

This returns 4 papers. Now, let's remove the keywords:

http://www-library.desy.de/cgi-bin/spiface/find/hep/www?rawcmd=FIND+A+POLCHINSKI++AND+DATE+%3E+2006+AND+DATE+%3C+2011&FORMAT=www&SEQUENCE=

This returns 15 papers. 11 of these papers are about strings or holography (explicitly in the AdS stringy approach). 4 papers are about cosmic strings which I am perfectly happy to describe as not string theory papers without looking at them. The DESY keyword search misrepresents Polchinski's production of string theory papers by a factor of almost 3.

There is no reason to expect that the keyword methodology is any more accurate for any of the other authors. Since you are the one attempting to claim its usefulness, the burden is on you to explain why we should believe that in the face of clear evidence to the contrary.

It is exceedingly unlikely that any useful conclusions about the nature of science will be drawn when the most basic principles of the scientific method cannot be grasped by those participating.
 
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atyy said:
marcus, do you think ground-breaking work can really be "managed"? ...

No, but visionary leadership certainly can help.

- string remains the first field of study for anyone interested in quantum gravity:
1)integrability in AdS/CFT
2)ABJM
3)twistors
4)many, many standard model like constructions

That's not the topic issue of the thread, I'm asking why and what can be done to revitalize the program. But I'm not convinced of your general statement that anyone interested in QG shoud first study String.

I think it's fairly clear that the main testing arena for QG (as empirical science) is early universe cosmology and possibly related stuff like gammaray burst observations. If someone is interested in QG they might do well to go to Penn State's Institute for Gravitation and the Cosmos and talk to Abhay Ashtekar. They might do well to learn some cosmology and quantum cosmology. And also get some handle on the current and projected job terrain.

But that's not the topic. I'm really looking for constructive ideas about the direction of the program.
 
YUK! Cosmic strings! If DESY catalogs cosmic strings papers as "string model" maybe their keywords are, in fact, deeply flawed. Thanks for pointing that out.

I will see if I can find some work-around for that.
 
marcus said:
That's not the topic issue of the thread, I'm asking why and what can be done to revitalize the program. But I'm not convinced of your general statement that anyone interested in QG shoud first study String.

I think it's fairly clear that the main testing arena for QG (as empirical science) is early universe cosmology and possibly related stuff like gammaray burst observations. If someone is interested in QG they might do well to go to Penn State's Institute for Gravitation and the Cosmos and talk to Abhay Ashtekar. They might do well to learn some cosmology and quantum cosmology. And also get some handle on the current and projected job terrain.

But that's not the topic. I'm really looking for constructive ideas about the direction of the program.

No, that is the topic. You claim it needs to be "revitalized". Of course everyone likes a breakthrough, but my claim is that your assumption that string isn't vital is wrong, hence any discussion that follows from it will be similarly flawed.
 
marcus said:
YUK! Cosmic strings! If DESY catalogs cosmic strings papers as "string model" maybe their keywords are, in fact, deeply flawed. Thanks for pointing that out.

I will see if I can find some work-around for that.

No, the cosmic string papers did not show up in the DESY keyword searches, they show up when I remove the keywords. The problem is the other 7 string papers that are not caught by your keyword search. One problem is that it is quite easy to write a paper on string theory without ever typing "string model" in the paper...
 
No, the cosmic string papers did not show up in the DESY keyword searches,...
What a relief! My faith in DESY librarians is to some extent restored!

So Atyy you argue there is no pressing need for some new vision or direction in the program. On the other hand, I still suspect that there is. But I am really more interested in what can be done. So I will just acknowledge your view that nothing needs to be done, and move on.

Let's look at Suprised's first four "wrong turns" and try to figure out how they could be fixed---so the core String unification program could get back on track (if it is not already on track :smile:.)

===quote Suprised post #553===
I guess there were many potentially wrong turns - at least in the sense of bias towards certain ways of thinking about string theory. Here a partial list of traditional ideas/beliefs/claims that have their merits but that potentially did great damage by providing misleading intuition:

  1. - That geometric compactification of a higher dimensional theory is a good way to think about the string parameter space
  2. - That perturbative quantum and supergravity approximations are a good way to understand string theory
  3. - That strings predict susy, or have an intrinsic relation to it (in space-time)
  4. - That strings need to compactify first on a CY space and then susy is further broken. That's basically a toy model but tends to be confused with the real thing.
...
==endquote==

Atyy, to me this provide a glimpse of renewal in the String unification program---which so far has interesting math but no one definite physical theory. You may disagree and say it has one definite physical theory and does not need renewal etc etc. But let's consider anyway how these things translate into action:

1. We should stop thinking of compactified extra dimensions as real. The world is 4D.

3. String has no intrinsic relation to SUSY. We should cut loose from the SUSY dream and not waste so much research on "superstuff"

2. That goes for SUGRA ("supergravity") too. Supergravity approximations are not a good way to understand String.

2. continued...Furthermore perturbative is not a good way. Perturbative uses a fixed prior setup---including a prior geometry---which is then subjected to small variations. You regard this approach as deficient.

4. We are warned against confusing Calabi-Yau spaces with reality.

========================

Can anybody else come up with some ideas for programatic reconsideration and reform?
 
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suprised's point #1 is in fact contained in David Tong's 2009 basic string theory notes, where it is given as a single sentence warning, which is where I learned about it. What I further learned from fzero and suprised was that in fact this warning can be useful in generating lots and lots of realistic models. Clearly the professionals have known about this for quite some time, and it's even trickled down to advanced undergrad and master level courses two years ago. Probably the only people who don't know about it in 2011 are biologists like me who read pop science books.
 
Purely as a point of interest, I note no change in percentage of papers by Michael Duff or Brian Greene that focus on 'core string theory'. It appears the same is true for the 'next generation' of theorists, e.g. Eva Silverstein (though, with her proclivity for humorous titles and my lack of knowledge of the field, it is a little hard for me to classify some of her papers).
 
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atyy said:
suprised's point #1 is in fact contained in David Tong's 2009 basic string theory notes, where it is given as a single sentence warning, which is where I learned about it. What I further learned from fzero and suprised was that in fact this warning can be useful in generating lots and lots of realistic models. Clearly the professionals have known about this for quite some time, and it's even trickled down to advanced undergrad and master level courses two years ago. Probably the only people who don't know about it in 2011 are biologists like me who read pop science books.

But as I and Haelfix have been pointing out in the other thread, the nongeometric models are likely to all appear as special points in CY models. The best that can be said is that these points are often easier to describe from the worldsheet perspective than other points in the moduli space of the same CY. It's not obviously correct to conclude that these are new models, not already contained in the space of CY compactifications.

Now what is a rather philosophic point is whether one should consider CY directions as spacetime dimensions or just as useful descriptions of the internal degrees of freedom. There are many situations where the geometric interpretation is very useful, since it allows us to use a certain amount of intuition, but it's not necessary per se. It's also almost unavoidable to use that intuition in trying to explain things to nonexperts, because "internal degrees of freedom" is an abstraction that obfuscates the construction to a high degree.

An added complication, familiar to experts, but not otherwise well known, is that the geometric interpretation of CY models is also itself really only valid over a corner of moduli space known as the large volume limit. That is, the emergence of a smooth geometry occurs when the volumes of the CY are large compared to the string scale. When the CY itself or submanifolds within the CY are of size order one in string units, both stringy and QG corrections to the smooth geometry are expected to be large. In some cases, the physics at points like this are understood nonperturbatively in terms of topology change and string dualities. In general one expects that a complete description of small volume requires the correct nonperturbative degrees of freedom. These may or may not be geometric. We have seen examples of both in the cases of matrix theory and AdS/CFT.

So I think that a string theorist needs to be aware of these issues. I have not seen evidence that successful ones are not intimately aware of the approximations and limitations attached to any particular string description.

I will comment a bit in the future on the point "3. String has no intrinsic relation to SUSY. We should cut loose from the SUSY dream and not waste so much research on "superstuff"" This statement may actually be true, but I think most of the evidence still favors an intimate relationship between spacetime SUSY and consistency of the superstring. It would actually take more than a few words to do justice to important work like that of Gato-Rivera and Schellekens who would like to argue otherwise.
 
fzero said:
... One problem is that it is quite easy to write a paper on string theory without ever typing "string model" in the paper...

I think I see your train of thought, there. :smile: Anyway we are now addressing Suprised's points and it's a more engrossing side to things.

PAllen said:
Purely as a point of interest, I note no change in percentage of papers by Michael Duff or Brian Greene that focus on 'core string theory'. It appears the same is true for the 'next generation' of theorists, e.g. Eva Slilverstein (though, with her proclivity for humorous titles and my lack of knowledge of the field, it is a little hard for me to classify some of her papers).

Thanks PAllen, I appreciate an more data like this that helps fill out the picture. You understand that by "core String" (which may have been a misnomer) I am only looking at the change over time of what Spires gives for dk "string model" and dk "membrane model".
A better classifier might be to call them DKSM papers. Maybe I'll add Michael Duff...

We are all more interested in the substantive physics correlatives here, so I'll say no more about that for now.
 
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marcus said:
Thanks PAllen, I appreciate an more data like this that helps fill out the picture. You understand that by "core String" (which may have been a misnomer) I am only looking at the change over time of what Spires gives for dk "string model" and dk "membrane model".
A better classifier might be to call them DKSM papers.

We are all more interested in the substantive physics correlatives here, so I'll say no more about that for now.

You still refuse to explain what you think DKSM papers are representative of. My claim is that they are not representative of any trend in research interest of individuals and I have given substantive arguments in support.

Let's do another experiment. We'll search DESY for keyword "quark model":

2007-2010
http://www-library.desy.de/cgi-bin/spiface/find/hep/www?rawcmd=FIND+%28DK+quark+MODEL+%29+AND+DATE+%3E+2006+AND+DATE+%3C+2011&FORMAT=www&SEQUENCE=
462 papers

2003-2006
http://www-library.desy.de/cgi-bin/spiface/find/hep/www?rawcmd=FIND+%28DK+QUARK+MODEL+%29+AND+DATE+%3E+2002+AND+DATE+%3C+2007&FORMAT=www&SEQUENCE=
28 papers

1999-2002
http://www-library.desy.de/cgi-bin/spiface/find/hep/www?rawcmd=FIND+%28DK+QUARK+MODEL+%29+AND+DATE+%3E+1998+AND+DATE+%3C+2003&FORMAT=www&SEQUENCE=
15 papers

How can we explain the cause of this profound new interest in quark models? Conversely, why were researchers not interested in the quark model from 1999-2006?

My answer is obviously that the keyword search itself is flawed.
 
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Yes perhaps this indicator is dreadfully flawed :smile:. We can still see what we make of it nonetheless.
PAllen kindly suggested looking at Michael Duff papers. So in a free moment I added Michael Duff and Gary Gibbons.
Probably this should be called the DESY "string" and "membrane" timeseries. For lack of better term it counts the DKSM (DESY keyword "string model" and "membrane model") papers over the past sixteen years 1995-2010. We look for differences and changes.

Code: 
          1995-1998      1999-2002      2003-2006      2007-2010
Witten         38             29              9              5
Strominger     23             14             22              4
Maldacena      27             33             24              9 
Polchinski     21             17             11              4
Harvey, J      16             15              9              2
Duff, M        24             17              8              5
Gibbons, G     17             29             11              2

It looks like Witten shifted interest (in DKSM terms) sooner than some others. Here are the Spires links so you can make your own counts if you like, using DESY keywords "string model" and "membrane model". Just put in a different name instead of Witten and repeat the search.

http://www-library.desy.de/cgi-bin/spiface/find/hep/www?rawcmd=a+Witten+and+%28dk+string+model+OR+dk+membrane+model%29+and+date+%3E+1994+and+date+%3C+1999&FORMAT=WWW&SEQUENCE= (38)

http://www-library.desy.de/cgi-bin/spiface/find/hep/www?rawcmd=find+a+witten+and+%28dk+string+model+or+dk+membrane+model%29+and+date+%3E+1998+and+date+%3C+2003&FORMAT=WWW&SEQUENCE= (29)

http://www-library.desy.de/cgi-bin/spiface/find/hep/www?rawcmd=find+a+witten+and+%28dk+string+model+or+dk+membrane+model%29+and+date+%3E+2002+and+date+%3C+2007&FORMAT=WWW&SEQUENCE= (9)

http://www-library.desy.de/cgi-bin/spiface/find/hep/www?rawcmd=find+a+witten+and+%28dk+string+model+or+dk+membrane+model%29+and+date+%3E+2006+and+date+%3C+2011&FORMAT=WWW&SEQUENCE= (5)
===========================
As a reminder that citation counts could also be significant. In case anyone is coming in new to the thread I will include this

Spires top cited articles during odd years 2001-2009
(with number of recent string papers making the top fifty shown in parenthesis)

http://www.slac.stanford.edu/spires/topcites/2001/annual.shtml (twelve)
http://www.slac.stanford.edu/spires/topcites/2003/annual.shtml (six)
http://www.slac.stanford.edu/spires/topcites/2005/annual.shtml (two)
http://www.slac.stanford.edu/spires/topcites/2007/annual.shtml (one)
http://www.slac.stanford.edu/spires/topcites/2009/annual.shtml (one)

A paper is counted as recent here if it appeared in the past five years.
 
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fzero said:
But as I and Haelfix have been pointing out in the other thread, the nongeometric models are likely to all appear as special points in CY models. The best that can be said is that these points are often easier to describe from the worldsheet perspective than other points in the moduli space of the same CY. It's not obviously correct to conclude that these are new models, not already contained in the space of CY compactifications.

Now what is a rather philosophic point is whether one should consider CY directions as spacetime dimensions or just as useful descriptions of the internal degrees of freedom. There are many situations where the geometric interpretation is very useful, since it allows us to use a certain amount of intuition, but it's not necessary per se. It's also almost unavoidable to use that intuition in trying to explain things to nonexperts, because "internal degrees of freedom" is an abstraction that obfuscates the construction to a high degree.

An added complication, familiar to experts, but not otherwise well known, is that the geometric interpretation of CY models is also itself really only valid over a corner of moduli space known as the large volume limit. That is, the emergence of a smooth geometry occurs when the volumes of the CY are large compared to the string scale. When the CY itself or submanifolds within the CY are of size order one in string units, both stringy and QG corrections to the smooth geometry are expected to be large. In some cases, the physics at points like this are understood nonperturbatively in terms of topology change and string dualities. In general one expects that a complete description of small volume requires the correct nonperturbative degrees of freedom. These may or may not be geometric. We have seen examples of both in the cases of matrix theory and AdS/CFT.

So I think that a string theorist needs to be aware of these issues. I have not seen evidence that successful ones are not intimately aware of the approximations and limitations attached to any particular string description.

I will comment a bit in the future on the point "3. String has no intrinsic relation to SUSY. We should cut loose from the SUSY dream and not waste so much research on "superstuff"" This statement may actually be true, but I think most of the evidence still favors an intimate relationship between spacetime SUSY and consistency of the superstring. It would actually take more than a few words to do justice to important work like that of Gato-Rivera and Schellekens who would like to argue otherwise.

I see, thanks. I had understood from yours and others replies in the other thread that while many non-geometric models can be reparamterized as CY compactifications, how extensive the equivalence was wasn't yet understood. Thanks also for clarifying that even the CY compactifications do not necessarily have a geometric interpretation. What are good examples of these, say in the context of AdS/CFT that you mention?
 
marcus said:
Yes quite possibly this indicator is dreadfully flawed. We can see what we make of it nonetheless.

[PLAIN]http://img600.imageshack.us/img600/5867/headexplode.jpg

atyy said:
I see, thanks. I had understood from yours and others replies in the other thread that while many non-geometric models can be reparamterized as CY compactifications, how extensive the equivalence was wasn't yet understood.

I try to be overconservative when I make statements. In this case, I was never an expert on these matters and it's been many years since I've had a reason to be familiar with them. In the case of the original Gepner models, Greene, Vafa and Warner http://inspirebeta.net/record/266451?ln=en gave the dictionary between them and CY manifolds. I tend to believe that other nongeometric theories will also be dual descriptions, but I can't be more specific. It might still be the case that the nongeometric phase is much better understood than the CY version, owing to small volume issues or whatever. If I turn up any better explanations in the literature, I'm sure that I'll share them.

Thanks also for clarifying that even the CY compactifications do not necessarily have a geometric interpretation. What are good examples of these, say in the context of AdS/CFT that you mention?

When I mentioned AdS/CFT, I was specifically referring to the nonperturbative degrees of freedom, in the sense that the CFT degrees of freedom are not geometric. The AdS/CFT actually deals with CYs that are in a large volume limit, since in the AdS5 case, our CY is a cone over a so-called Einstein-Sasaki 5-manifold, [tex]X_5[/tex]. We can still have submanifolds going singular, like the conifold point. There the geometric naively becomes singular, but the singularity is understood in terms of a tower of wrapped D-brane states becoming light. In the dual gauge theory, this picture is understood as Seiberg duality, due to Klebanov and Strassler in this context.
 
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heh heh, great illustration! :biggrin:
Obviously I don't consider it flawed when applied in this context, but I can see how you might think like that.
 
I updated the list by adding Dijkgraaf and Ooguri
marcus said:
Yes perhaps this indicator is dreadfully flawed :smile:. We can still see what we make of it nonetheless.
PAllen kindly suggested looking at Michael Duff papers. So in a free moment I added Michael Duff and Gary Gibbons.
Probably this should be called the DESY "string" and "membrane" timeseries. For lack of better term it counts the DKSM (DESY keyword "string model" and "membrane model") papers over the past sixteen years 1995-2010. We look for differences and changes.

Code: 
          1995-1998      1999-2002      2003-2006      2007-2010
Witten         38             29              9              5
Strominger     23             14             22              4
Maldacena      27             33             24              9 
Polchinski     21             17             11              4
Harvey,J       16             15              9              2
Duff,M         24             17              8              5
Gibbons,G      17             29             11              2
Dijkgraaf      18             11              9              7
Ooguri         31             18             13              8
Silverstein,E  16             15             16             10

=======================
Notice that for Eva Silverstein the numbers are roughly flat. Thanks to PAllen for suggesting both Silverstein and Duff. I just edited Silverstein into the sample, at his suggestion.

It strikes me that maybe the easiest thing to do is deny there is a problem, or that anything has happened. To say the DESY librarians are inconsistent/arbitrary in their tagging. To say there is some harmless explanation, or to accuse the reporter of stupidity or bias or sinister motives :biggrin: And then there is nothing to talk about.

We don't want to forget about citation counts, since cites to recent papers reflect the researchers' assessment of their own colleagues' current output. So this has to be factored in with numbers of papers as an indicator of value (sometimes called the "impact" of the research.) It has gone down.

Spires top cited articles during odd years 2001-2009
(with number of recent string papers making the top fifty shown in parenthesis)

http://www.slac.stanford.edu/spires/topcites/2001/annual.shtml (twelve)
http://www.slac.stanford.edu/spires/topcites/2003/annual.shtml (six)
http://www.slac.stanford.edu/spires/topcites/2005/annual.shtml (two)
http://www.slac.stanford.edu/spires/topcites/2007/annual.shtml (one)
http://www.slac.stanford.edu/spires/topcites/2009/annual.shtml (one)

A paper is counted as recent here if it appeared in the past five years.
=========================

Sure this could conceivably all be artifacts of some harmless/meaningless circumstance.
Paper and cite counting makes no pretense of being "science". It's just the kind of thing one normally does as part of finding out what's happening in a field.

I like what Suprised, Tom, and others are doing in that other thread though. Trying to come to grips with what may be wrong in the program. Or have been wrong but is in the process of fixing itself.
 
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Two observations:

Eva Silverstein shows no real decline (15, 16, 10)

A key thing to independently verify is a shift in general usage of keywords. Not inconsistency of librarians, but evolution of meaning of terminology. Hopefully, the librarians respond to changing concepts. Thus, a given paper may be classified differently today than in the past. Also, as research gets more specialized, the terms applied to something 'part of the unification goal' may also become more varied and specialized. Finally, what looks like a side issue may be, to its author and other experts in the field, a promising way to get at a central issue in unification.

So though I sympathize with the attempt to come up with a simple, objective metric of activity, I really doubt it can be done. There is no alternative to a fair expert in the field judging which papers are part of the effort towards string/M as a unified theory, versus applications of its techniques to other fields; with the further complication that an 'application' paper may be intended to get at a 'central' issue by an indirect route.
 
PAllen, nicely put!

There is a tradeoff between a quick and dirty indicator that is easy to use to get a rough idea of something versus careful work by a guaranteed unbiased expert. And I do suspect DESY librarians of changing how they classify papers and assign tags. Probably less so with very common terms that have been in use for a long time.

I'm glad to get your suggestion of Eva Silverstein and will add her to the list up in post #51. So far I have been putting in whoever occurred to me, without looking first---no cherrypicking :biggrin:--and I've been suprised at the rather consistent pattern. It is helpful now to have Silverstein as an example to show that it is possible to have a flatter output of DKSM papers. Here are the Spires links again so anyone can do it. Just put in a different name instead of Silverstein, E and repeat the search.

http://www-library.desy.de/cgi-bin/spiface/find/hep/www?rawcmd=a+Silverstein, E +and+%28dk+string+model+OR+dk+membrane+model%29+and+date+%3E+1994+and+date+%3C+1999&FORMAT=WWW&SEQUENCE= (16)

http://www-library.desy.de/cgi-bin/spiface/find/hep/www?rawcmd=find+a+Silverstein, E+and+%28dk+string+model+or+dk+membrane+model%29+and+date+%3E+1998+and+date+%3C+2003&FORMAT=WWW&SEQUENCE= (15)

http://www-library.desy.de/cgi-bin/spiface/find/hep/www?rawcmd=find+a+Silverstein, E+and+%28dk+string+model+or+dk+membrane+model%29+and+date+%3E+2002+and+date+%3C+2007&FORMAT=WWW&SEQUENCE= (16)

http://www-library.desy.de/cgi-bin/spiface/find/hep/www?rawcmd=find+a+Silverstein, E+and+%28dk+string+model+or+dk+membrane+model%29+and+date+%3E+2006+and+date+%3C+2011&FORMAT=WWW&SEQUENCE= (10)
 
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The question of the number of recent string papers among top cited papers for recent years (which really does seem to have gone down a lot) has many possible explanations to be sorted out, and I believe all of these are actually contributing:

1) The more mature a field is, the more of its breakthrough papers will be older. There is no shortage of string papers among the 2009 cites; just that many of them are not 'recent' (I get about 9 if I don't limit to recent).

2) There actually haven't been many breakthroughs recently, despite continued effort (nothing new of the order of ADS/CFT, dualities, black hole results).

3) Other areas have become 'hot', pushing aside recent string papers (e.g. gear up to LHC and astronomy / cosmology)

4) More active participants, less reliance on superstars, in a field of unchanged significance relative to physics as a whole, will lead to fewer top cited recent papers.

Of these, only (2) is a possible problem for a research program, and only if it continues 'too long', however that might be defined.
 
marcus said:
I'm glad to get your suggestion of Eva Silverstein and will add her to the list up in post #51. So far I have been putting in whoever occurred to me, without looking first---no cherrypicking :biggrin:--and I've been suprised at the rather consistent pattern. It is helpful now to have Silverstein as an example to show that it is possible to have a flatter output of DKSM papers. Here are the Spires links again so anyone can do it. Just put in a different name instead of Silverstein, E and repeat the search.

I certainly didn't suggest Eva Silverstein by cherry picking (looking for someone with flat output). She is simply someone I've been aware of and follow a bit; in part because she sometimes picks quite funny titles for her papers (spring is coming - "dual purpose landscaping tools" anyone?)
 
PAllen said:
I certainly didn't suggest Eva Silverstein by cherry picking (looking for someone with flat output). ... - "dual purpose landscaping tools" anyone?)

It actually never crossed my mind that you might have. We both realize, I think, that the value of informal spot checks like this is mainly of interest to the persons who make them and only of value if you have no idea how they'll turn out. Landscaping tools is funny. I've watched a video lecture by her before an expert audience and was impressed. Poised personable articulate and, one gathers, highly intelligent.

My favorite String speaker (when I watch the annual conference talks) is Andy Strominger. His frankness/integrity made a deep impression on me in 2005 when I watched the Strings 2005 panel discussion on "The Next String Theory Revolution". He was on the panel with Silverstein, Bousso, Kacchru, Maldacena as I recall (I'll check and correct, not sure of other names) and he was positive without gloss or wishful thinking. Inspired my trust.
He's someone I would never expect to go faddy or multiverse. (Just personal subjective reactions, don't expect anyone to share them.)

Among the older ones I always like David Gross. He occasionally shows some of the same clearsighted honesty that I admire in Strominger.
==============
I refreshed my memory: the Strings 2005 panelists were
Raphael Bousso (UC Berkeley)
Shamit Kachru (SLAC & Stanford)
Ashok Sen (Harish-Chandra Research Institute)
Juan Maldacena (IAS, Princeton)
Andrew Strominger (Harvard)
Joseph Polchinski (KITP & UC Santa Barbara)
Eva Silverstein (SLAC & Stanford)
Nathan Seiberg (IAS, Princeton)
http://www.fields.utoronto.ca/programs/scientific/04-05/string-theory/strings2005/panel.html
The moderator was Steve Shenker
who said "holy sh*t!" on mike when he was surprised by an overwhelming show-of-hands vote by the 400-some audience of string theorists. The rankandfile went against the multiverse anthropic landscape view, which was then prevalent among the leadership/conference organizers. A sweet moment.
 
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In the "REALLY disappointed with string" thread, Suprised earlier listed some wrong turns which potentially caused staleness/damage in the String program. These included thinking of extra dimensions as really there, too much emphasis given to perturbation on fixed geometric backgrounds,...and several other things I would classify as program direction errors---deficiencies of vision in program leadership. Such things can be presumably be remedied if you try.

So far we hear central people like David Gross crying out for a missing new idea that will allow the program to make real progress, but there are no suggestions as to what the new idea could be. Gross has mentioned that it might be a fundamentally new concept of space and time.

We always have the latest hopeful mathematical excitements (e.g. ABJW Aharony, Bergman, Jafferis, Witten 2008*) but that does not seem to satisfy the need.

Suprised is the only stringster in my vicinity who sometimes seems to be seriously searching, so I appreciate this kind of exchange:

tom.stoer said:
My question is this: dropping uniqueness as guiding principle, do you have a something new?

suprised said:
... So it may be that there is a bunch of "different" underlying theories that lead all lead to the same on-shell physics.

Essentially, this boils down to semantics and what one means by "unique" underlying theory. Eg., is lattice QCD a "different" theory as compared to the usual perturbative lagrangian formulation of QCD? No, because when performing the proper limits it lies in the same universality class. A similar phenomenon could happen eg for LQG and strings, etc.

What does this mean?
==quote==
... Eg., is lattice QCD a "different" theory as compared to the usual perturbative lagrangian formulation of QCD? No, because when performing the proper limits it lies in the same universality class. A similar phenomenon could happen eg for LQG and strings,...
==endquote==

It sounds like an analogy: there are two related quasi-equivalent theories, lattice QCD and perturbative Lagrangian QCD---he seems to be imagining that LQG could turn out to be analogous to the lattice version and some string construction analogous to the perturbative. So the two discover they are cousins.

*http://arxiv.org/abs/0806.1218

=================
The Strings 2005 panel that discussed what they saw as prospects for "The Next String Theory Revolution" was intentionally handpicked to represent "young stars", prominent figures in the rising generation. I picked another name, Nathan Seiberg, from that list, not knowing how the numbers would turn out, and added him to the table.
Code: 
          1995-1998      1999-2002      2003-2006      2007-2010
Witten         38             29              9              5
Strominger     23             14             22              4
Maldacena      27             33             24              9 
Polchinski     21             17             11              4
Harvey,J       16             15              9              2
Duff,M         24             17              8              5
Gibbons,G      17             29             11              2
Dijkgraaf      18             11              9              7
Ooguri         31             18             13              8
Silverstein,E  16             15             16             10
Seiberg,N      19             16             22              1

=======================
If you would like to check Spires keyword string or membrane publication numbers for anyone, here are the links. Just put in another name for "Silverstein, E" in these links and please let us know what you get!

http://www-library.desy.de/cgi-bin/spiface/find/hep/www?rawcmd=a+Silverstein, E +and+%28dk+string+model+OR+dk+membrane+model%29+and+date+%3E+1994+and+date+%3C+1999&FORMAT=WWW&SEQUENCE= (16)

http://www-library.desy.de/cgi-bin/spiface/find/hep/www?rawcmd=find+a+Silverstein, E+and+%28dk+string+model+or+dk+membrane+model%29+and+date+%3E+1998+and+date+%3C+2003&FORMAT=WWW&SEQUENCE= (15)

http://www-library.desy.de/cgi-bin/spiface/find/hep/www?rawcmd=find+a+Silverstein, E+and+%28dk+string+model+or+dk+membrane+model%29+and+date+%3E+2002+and+date+%3C+2007&FORMAT=WWW&SEQUENCE= (16)

http://www-library.desy.de/cgi-bin/spiface/find/hep/www?rawcmd=find+a+Silverstein, E+and+%28dk+string+model+or+dk+membrane+model%29+and+date+%3E+2006+and+date+%3C+2011&FORMAT=WWW&SEQUENCE= (10)
 
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marcus said:
In the "REALLY disappointed with string" thread, Suprised earlier listed some wrong turns which potentially caused staleness/damage in the String program. These included thinking of extra dimensions as really there, too much emphasis given to perturbation on fixed geometric backgrounds,...and several other things I would classify as program direction errors---deficiencies of vision in program leadership. Such things can be presumably be remedied if you try.

marcus, you again misquote me and give things a spin in your direction. These were not wrong turns per se, but partly too naive or too simple, perhaps sometimes misleading views, most of them have already been overcome over the years, and the insiders know these issues pretty damn well. It's you non-experts who continue to be confused and criticize non-issues, have an obsession against extra dimensions, etc.

And there is no such thing as a "deficiency in program leadership" ! This is simple a naturally evolving subject, period. I wouldn't even know where to pinpoint any "program leadership" in the first place. It seems you don't have any idea how things work.

Please stop picking out single phrases and presenting them in a new package that has a different spin than originally intended. If my words continue to be misrepresented in this manner, I won't write any more.
 
Suprised, I'm glad to have any correction from you about the interpretation of your words. It can be very irritating to be misunderstood and misconstrued. This happens to me also, so I can sympathize! I do want to get what you are saying right.

I will go back and quote the post I was thinking of, and let you speak for yourself rather than paraphrase. This is the complete post #523. I don't want to take anything out of context. Please clarify and interpret as you think fitting:

suprised said:
tom.stoer said:
Last but not least my feeling is that at a rather early stage there was a wrong turn (I cannot tell exactly which one) which prevents us from asking the right questions ...
Perhaps there are string theorists here able to tell us what could have been this wrong turn in the very beginning.
I guess there were many potentially wrong turns - at least in the sense of bias towards certain ways of thinking about string theory. Here a partial list of traditional ideas/beliefs/claims that have their merits but that potentially did great damage by providing misleading intuition:

- That geometric compactification of a higher dimensional theory is a good way to think about the string parameter space
- That perturbative quantum and supergravity approximations are a good way to understand string theory
- That strings predict susy, or have an intrinsic relation to it (in space-time)
- That strings need to compactify first on a CY space and then susy is further broken. That's basically a toy model but tends to be confused with the real thing
- That there should be a selection principle somehow favoring "our" vacuum
- That a landscape of vacua would be a disaster
- That there exists a unique underlying theory
- That things like electron mass should be computable from first principles

Most of these had been challenged/revised in the recent years, and many people think quite differently about them than say 15-20 years ago.

Sorry about any inadvertent misquote or incorrect spin. Please clarify and give a more correct spin!
suprised said:
marcus, you again misquote me and give things a spin in your direction. These were not wrong turns per se, but partly too naive or too simple, perhaps sometimes misleading views, most of them have already been overcome over the years, and the insiders know these issues pretty damn well. It's you non-experts who continue to be confused and criticize non-issues, have an obsession against extra dimensions, etc.

And there is no such thing as a "deficiency in program leadership" ! This is simple a naturally evolving subject, period. I wouldn't even know where to pinpoint any "program leadership" in the first place. It seems you don't have any idea how things work.

Please stop picking out single phrases and presenting them in a new package that has a different spin than originally intended. If my words continue to be misrepresented in this manner, I won't write any more.
 
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suprised said:
I wouldn't even know where to pinpoint any "program leadership" in the first place. It seems you don't have any idea how things work. .

Hmm, about this, someone mentioned "lamp-post methodology" in the first thread, and I tend to agree that this is the way things work. Mainly because of responsability of the leadership: one must be involved in research that the pupils, the PhD students, will be able to produce and publish in a period of 4-6 years. Plus, the same thing for postdocts and profesorships. So it is natural to giave preference to productive areas.