- #71
tom.stoer
Science Advisor
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I am not so sure; I think he simply follows and continuously criticizes a way taken by a small minority of string theorists.
Last edited:
tom.stoer said:...Second some physicists think that discussing these problems weakens the position of the research program;... That results in supressing discussions and therefore hinders, slows down or even stops progress of science.
Third (and this is a kind of self-fulfilling prophecy) unfairly dismissing objective criticism strengthens the position of the critics. ...
atyy said:As we now know from relative locality, marcus is in his own momentum space with respect to "an objective observer of string theory."
marcus said:Heh heh, by the principle of relative locality, so is each one of us including you, Atyy
ABJM? Anybody for twistors? Anti-deSitter condensed matter?
tom.stoer said:...continuously criticizes a way taken by a small minority of string theorists.
marcus said:String experts have decided after several decades experience that one should NOT think in terms of strings and branes in a geometry with compactified extra dimensions. What is the theory if one discards the central paradigm?
fzero said:With all due respect to surprised, both Haelfix and I have explained several times now how CY compactifications are thought to be universal...
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
marcus said:Thanks fzero! I think what you are showing me is that it is controversial. Many in the String program (but not all!) have concluded that strings/branes in compactified extraD are the wrong way to go. I can't say which POV is in the majority and maybe that does not matter.
You commented about evidence. Here is some supporting evidence. This is a sample of famous stringsters whose names just happened to occur to me and to PAllen. I didnt look at their papers first before deciding to put them on the list. DESY librarians make a professional classification of papers---they decide which papers to tag "string model" and "membrane model". The indication is that the top people USED to write papers explicitly involving strings/branes and that they do that much less. Not HARD evidence, but a suggestive straw in the wind.
marcus said:This seems to support what a respected Pro said here earlier about "many" String people. I'll not paraphrase since I might unintentionally err. But I would say this suggests that among the top people there has been a huge shift out of explicitly string/brane research proper. If you want the Spires links, go back to post #63.
No indicator is perfect. I see a huge decline and I doubt that there is a conspiracy on the part of the librarians to engineer a systematic misclassification.fzero said:...
I've tried to explain multiple times why the DESY keywords cannot be completely trusted. In some cases they are correct, in others they are misleading...
marcus said:This is a large part of the point I wanted to make in this thread. There has been a major shift in research activity---sometimes I refer to it as research "interest" but what I'm looking at is objective stuff like citation counts and papers written and what topics get featured at the annual Strings 2010 or 2011. At least quality-wise, in terms of highly cited papers, there has been a decline of activity in core areas of the program.
Naturally one wants to know why. And what the new picture is that is taking shape.
BTW may I assume you mean the grant requests that people put in for funding? Not the grants themselves but the grant proposals?
It does not matter for him, fzero! He'll keep ignoring this point over and over and over again because it does not fit his agenda. He'll copy and paste a part of your response that he finds useful to promote his propaganda. Marcus has reposted his "data analysis" about 10 times now, while fzero's much more careful estimate is buried in the middle of the thread. This is a classic strategy - "If you repeat a lie often enough, it becomes the truth." The end result is that some lay people will be left with impression that there is indeed some decline, not because Marcus is right, but because he's better at repeating the garbage. At the same time, in a different thread, Marcus is promoting an idea that some papers on the theory of angular momentum, computing 12j and 15j symbols, constitute research on LQG :rofl: . Any well informed person realizes how ridiculous that is but it does not matter.fzero said:In post #24, I made a detailed analysis of Witten's publications, being very conservative about which papers should be considered string theory. There was no evidence that he had shifted out of string theory.
They do not confront what? The positive cosmological constant? Have you ever looked at the title of the KKLT paper, which came out in 2003? FYI, it it called "de Sitter vacua in String Theory".marcus said:I will say where I am coming from, regarding these issues. I think Final Theory is a wild goose El Dorado. Physics must be pragmatic and incremental. ...
So any theory of gravity must at least include a positive cosmological constant. Like the classic gravity equation does. I'm happy to be contradicted on this and be given counterarguments, but this is where I am coming from. String program leaders misguide the program if they do not confront this---and maybe they already do and I just didn't hear about it.
Really, Marcus? Is that what it's all about? Seriously, until you change your criteria and follow fzero's suggestion for a more accurate analysis, instead of repeating the garbage, your point is moot. I'm sure that suprised, Haelfix, fzero and other reputable people on this forum see the same thing, they are just a bit more diplomatic in expressing their frustration with what you've been doing here. I'm much more blunt b/c I can't stand the BS you are spreading.marcus said:But I'm not convinced of your general statement that anyone interested in QG shoud first study String.
...
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.
smoit said:As I said before, this whole "discussion" and "data mining" is directed towards the uninformed souls, interested in BSM physics, in an attempt to steer them away from string-oriented research by convincing them that there is some decline in the String program.
Below is the very reason for why this and similar threads with data "confirming" the thread title were started in the first place.
Really, Marcus? Is that what it's all about? Seriously, until you change your criteria and follow fzero's suggestion for a more accurate analysis, instead of repeating the garbage, your point is moot. I'm sure that suprised, Haelfix, fzero and other reputable people on this forum see the same thing, they are just a bit more diplomatic in expressing their frustration with what you've been doing here. I'm much more blunt b/c I can't stand the BS you are spreading.
unusualname said:You really are a very rude person.
This type of speech will look funny in restropect when the dust settles, you should reign in your vitriol so as not to appear too ridiculous,
marcus said:Hello Tom I hope you had a good summer. You are heartily welcome to read some LQG with me in spare moments as long as you are spending enough time on a well-rounded realworld program.
...
the reason LQG is heating up now is because it gives some indications of approaching that point. It doesn't have to do with being beautiful or divinely inspired. it has to do with the fact that without much fanfare a version of
LQG has, curiously enough, already been falsified. Synchrotron radiation from the Crab Nebula tested and shot down Smolin's Version A of LQG and it looks like Version B will be testable within maybe 4 years.
this is why, if you ever want to know about LQG, you should read
"Invitation to LQG" by smolin. It has almost no formulas--you can probably understand an important 20 or 25 percent of it. It has an FAQ written for
physicists from other fields. And most importantly it describes the
near term experimental situation
this paper is dynamite and it is the one of the very few papers I can imagine wanting to read with you or anyone at PF at this moment
...
Here is the post that you are referring to:smoit said:Marcus is promoting an idea that some papers on the theory of angular momentum, computing 12j and 15j symbols, constitute research on LQG :rofl: . Any well informed person realizes how ridiculous that is but it does not matter.
...
marcus said:The fact is that the Wigner 15j is key to 4d spinfoam LQG, just as the 6j was key to Ponzano-Regge 3d gravity. Understanding the asymptotics of the 15j is critical for establishing the large-scale limit of LQG. Large scale means large j---so one needs to understand the limit of the 15j symbol for large j. ...
marcus said:...
Is this Loop? You know from review papers that Loop draws heavily on several of the types of mathematics mentioned by the DESY librarians as keywords. But that does not make the paper Loop. I have to use an automatic criterion in order to tabulate changes---so I do not try to second-guess the DESY, I just go by what keywords they tag on the paper. They don';t say "quantum gravity, loop space" or "quantum cosmology, loop space" or "spin, foam" so I don't count it.
marcus said:Several of the papers contain extensive references to LQG research and discuss their relevance to the Loop program. ...
:zzz:smoit said:So, let's try your favorite approach on some of the allegedly LQG papers from Berkeley:
...
...
http://www-spires.fnal.gov/spires/find/hep/wwwtopics?key=8787883"
List of keywords assigned to the paper: Semiclassical Mechanics of the Wigner $6j$-Symbol
phase space, reduced
spin, network
semiclassical
mechanics
higher-dimensional
WKB approximation
angular momentum
Poisson bracket
integrability
symplectic
So, are these papers LQG or not, Marcus?
But what you get from AdS/CFT are low-dimensional field theories in flat space being equivalent to an AdS space times a compact space, containing strings and branes. The radial AdS dimension encodes the RG flow, and the compact space (and the objects with extension in it) is "made from" the space of ground states of the field theory. From this perspective, string theory is the universal theory of emergent RG geometry in quantum field theory. At the moment, it only works properly for an emergent AdS space, but if the dS/CFT correspondence can be understood, then this will be true for spaces of positive curvature as well. (In dS/CFT the boundary is purely spacelike and lies in the infinite past and future, rather than being timelike as in AdS/CFT, so it's as if the timelike direction in the Lorentzian gravitational space is emerging from Euclidean field theory on a sphere in the infinite past.)marcus said:String experts have decided after several decades experience that one should NOT think in terms of strings and branes in a geometry with compactified extra dimensions.
When you do a careful and proper statistical analysis you'll see that there is no decline of interest, as fzero has already confirmed. This is the point that YOU are deliberately ignoring. In particular, in your estimates you are completely ignoring the decline in the total number of papers put out by the same author in a given time period. It is completely natural for older professors to be less active and put out fewer papers. For instance, Eva Silverstein is from the younger generation and is still rather active, hence her absolute number of all papers, includings those on string theory, has not at all declined.fzero said:Marcus, I've tried to explain to you before that these keyword search statistics are extremely bad science. Besides not taking into account many statistical concepts such as sample size, it is not even clear that keywords are an effective substitute for just looking at the papers and recognizing what they are about. If you want to do statistics in a way that any scientist can respect, you must actually understand the properties of the sample, have some quantity in mind that is supposed to be of statistical significance, and then actually attempt to quantify the degree of correlation of your hypothesis with the sample. Absence of any of these results in a garbage in-garbage out situation.
To see how far off the mark your keyword searches were, I actually looked at all Witten papers for the periods > 2002- < 2007 and > 2006 - < 2011. These were obtained by using your date ranges in inspire, without the keywords. There is some overlap between the two periods, possibly because papers that appeared in the arxiv in 2006 also appeared in journals in 2007. Statistically, the overlap is not of much significance.
I attempted to classify papers which were string-related and those which were not. Basically my criteria were:
String: About strings, branes or 2d topological qft. Also includes AdS/CFT, the initial twistor amplitude paper and any Langlands papers that refer directly to 2d mirror symmetry.
Other: Papers about straight qft including particle physics, Chern-Simons and exotic qfts that don't directly imply string relations in their abstract or title. Also includes papers about pure 3d quantum gravity.
Results are:
2003-2006 http://inspirebeta.net/search?ln=en...+2002+AND+DATE+<+2007&f=&action_search=Search
-52 total papers
-15 conference proceedings
* 8 QFT
* 7 string
-37 journal articles
* 15 QFT
* 3 QG
* 19 string2007-2010 http://inspirebeta.net/search?ln=en...n_search=Search&sf=&so=d&rm=&rg=25&sc=0&of=hb
-25 total papers
-5 conference proceedings
* 5 QFT
-20 journal articles
* 9 QFT
* 2 QG
* 9 stringThe first thing to notice is that Witten's total output in 2007-2010 was half that for the 3 yrs prior. Measurements for this period will be less statistically significant as a result. As for relevant ratios,
2003-2006: 50% of total were string, 51% of journal articles were string
2007-2010: 36% of total were string, 45% of journal articles were string
It is amusing to do some statistics. Suppose that Witten's papers are randomly distributed between string and nonstring physics, and that the topics of papers are independent of previous papers. Then we have a binomial distribution. With 35 string papers in 77 trials, we have [tex]p=0.45[/tex]. For the two periods we have
2003-2006: expected number of string papers: 52(0.45) = 24
variance: 52(0.45)(0.55) = 13
actual number of string papers: 26
expected: [tex]24\pm 3.6[/tex]
2007-2010: expected number of string papers: 25(0.45) = 11
variance: 25(0.45)(0.55) = 6
actual number of string papers: 9
expected: [tex]11\pm 2.4[/tex]
In both cases the number of string papers produced is within one standard deviation of the expected result. There is no reason to conclude that Witten has lost interest in string theory between these two periods.
You are free to conduct a similar analysis over a larger data sample, or for other notable string theorists. The results might be interesting. Keyword search results with no analysis will not be.
atyy said:marcus, as you know, I disagree with your definitions. But I want to find out how strict they are. Let's say LQG goes in the direction of AdS/LQG, would you count that as LQG or not?
marcus said:Let's not waste time on "metaphysics". We know who the leaders are in LQG, if I saw them doing "AdS/LQG" whatever that means then I'd probably say yes that is included in Loop gravity.
1995-1998 1999-2002 2003-2006 2007-2010
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
marcus said:You've got me curious now. Do you have anything particular in mind for AdS/LQG? Any research paper? Freidel wrote something about AdS/CFT correspondence a while back: 2008? But I would not call that AdS/LQG, not in a serious moment anyway.
marcus said:Atyy,
You seem to be taking issue with DESY cataloguing. What impresses me is the huge decline during the period 2003-2005, among a sample of top people. It would be interesting to know what other areas (whether or not you want to say they are "really" String) those people went into. Someone was claiming that the Langland's program was "really" String and "should" be counted. This is questionable. But that was just in the case of one person out of 10 or so. They pretty much all showed the same abrupt drop. So far not adequately explained away.
Still, if the DESY classification bothers you, here is a measure of declining interest that is not based on DESY. In making these counts I tried to be inclusive in deciding what was string. I don't recall anyone pointing out a paper I missed: i.e. one not counted which they think is "really" a string paper. Make your own counts, if you want, and see if your numbers agree with mine.
Cites to recent String papers reflect the researchers' assessment of the value of their own colleagues' current output.
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.
=========================
Last month, MTd2 said something about https://www.physicsforums.com/showthread.php?t=484836#6". My intuition says that's another possible starting point for "AdS/LQG". The reason is just that braids mean something in (2+1) dimensions, and ABJM is the prototypical d=3 theory with an AdS4 dual.atyy said:AdS/LQG
mitchell porter said:Last month, MTd2 said something about https://www.physicsforums.com/showthread.php?t=484836#6". My intuition says that's another possible starting point for "AdS/LQG". The reason is just that braids mean something in (2+1) dimensions, and ABJM is the prototypical d=3 theory with an AdS4 dual.
What I am tracking here is the value or quality of CURRENT STRING RESEARCH output.atyy said:Maldacena's paper was cited 392 times in 2001, and 696 times in 2009, clearly showing a decline in interest in string?
fzero said:Marcus, I've tried to explain to you before that these keyword search statistics are extremely bad science. Besides not taking into account many statistical concepts such as sample size, it is not even clear that keywords are an effective substitute for just looking at the papers and recognizing what they are about. If you want to do statistics in a way that any scientist can respect, you must actually understand the properties of the sample, have some quantity in mind that is supposed to be of statistical significance, and then actually attempt to quantify the degree of correlation of your hypothesis with the sample. Absence of any of these results in a garbage in-garbage out situation.
To see how far off the mark your keyword searches were, I actually looked at all Witten papers for the periods > 2002- < 2007 and > 2006 - < 2011. These were obtained by using your date ranges in inspire, without the keywords. There is some overlap between the two periods, possibly because papers that appeared in the arxiv in 2006 also appeared in journals in 2007. Statistically, the overlap is not of much significance.
I attempted to classify papers which were string-related and those which were not. Basically my criteria were:
String: About strings, branes or 2d topological qft. Also includes AdS/CFT, the initial twistor amplitude paper and any Langlands papers that refer directly to 2d mirror symmetry.
Other: Papers about straight qft including particle physics, Chern-Simons and exotic qfts that don't directly imply string relations in their abstract or title. Also includes papers about pure 3d quantum gravity.
Results are:
2003-2006 http://inspirebeta.net/search?ln=en...+2002+AND+DATE+<+2007&f=&action_search=Search
-52 total papers
-15 conference proceedings
* 8 QFT
* 7 string
-37 journal articles
* 15 QFT
* 3 QG
* 19 string
2007-2010 http://inspirebeta.net/search?ln=en...n_search=Search&sf=&so=d&rm=&rg=25&sc=0&of=hb
-25 total papers
-5 conference proceedings
* 5 QFT
-20 journal articles
* 9 QFT
* 2 QG
* 9 string
The first thing to notice is that Witten's total output in 2007-2010 was half that for the 3 yrs prior. Measurements for this period will be less statistically significant as a result. As for relevant ratios,
2003-2006: 50% of total were string, 51% of journal articles were string
2007-2010: 36% of total were string, 45% of journal articles were string
It is amusing to do some statistics. Suppose that Witten's papers are randomly distributed between string and nonstring physics, and that the topics of papers are independent of previous papers. Then we have a binomial distribution. With 35 string papers in 77 trials, we have [tex]p=0.45[/tex]. For the two periods we have
2003-2006: expected number of string papers: 52(0.45) = 24
variance: 52(0.45)(0.55) = 13
actual number of string papers: 26
expected: [tex]24\pm 3.6[/tex]
2007-2010: expected number of string papers: 25(0.45) = 11
variance: 25(0.45)(0.55) = 6
actual number of string papers: 9
expected: [tex]11\pm 2.4[/tex]
In both cases the number of string papers produced is within one standard deviation of the expected result. There is no reason to conclude that Witten has lost interest in string theory between these two periods.
You are free to conduct a similar analysis over a larger data sample, or for other notable string theorists. The results might be interesting. Keyword search results with no analysis will not be.