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Don’t you think it’s good to link to the talk resource pages that the conference offers (such as indico.cern.ch/event/1085701/contributions/4940799)? It seems advantageous in several respects: the indico-number gives a stable way to cite the talk, the page gives further references such as to time and place it was held, and potentially further material might later be found on these pages.
Is there a reason that this particular conference merits a page?
Is there a reason that other conferences didn’t get their nlab page? Yes: lack of volunteers who go ahead and make interesting additions to the nLab. Glad that somebody here did. (Maybe it was prodded by the trolling here).
it was because Urs Schreiber requested that the Strings 2022 be created when I was inserting references to operator product expansion and Natalie Paquette.
Not that it matters much, but what I actually wrote is here: Initially I had removed the link to a (then non-existent) nLab page with the title “String 2022”. You then went ahead and created it nonetheless – which is great, I am not complaining. :-)
Always, the more hands the merrier.
Also, I just read the other thread on Strings 2022, and I don’t really think that the OP is trolling. I just think that they consider “string theory” to mean only the 11 dimensional string theory which was heavily researched in the 1980s and 1990s.
While they are right in pointing out that the string theory community has largely moved on from the string theory studied in the 1990s, I disagree with their notion that string theory only consists of one such unified theory of everything. String theory is a framework in the same way that quantum field theory is a framework, and classical field theory is a framework, and it began as a theory of the strong force and will live on in other fields such as condensed matter physics, long after the dominant approaches to force unification and quantum gravity have been replaced with other approaches.
I also think that this divide over what exactly “string theory” is is a legitimate divide in theoretical physics, among both supporters and critics of string theory, especially in a time of flux when it isn’t clear what the purpose of string theory is, since the failure of LHC to discover supersymmetry meant that the string theory community has become virtually detached from its origin in high energy physics and unification.
I’m commenting here because guests don’t have the ability to comment on the other page for some reason.
To elaborate: among supporters of string theory as a theory of everything there is a debate over whether string theorists should be entering into quantum information science and condensed matter physics and doing interdisciplinary research, and whether the interdisciplinary research that string theorists are doing in quantum information science and condensed matter physics is actually productive to the end goal of coming up with a theory of everything or is just a dead end, with the likes of Edward Witten on one side, and the swampland people like Cumrun Vafa on the other.
With critics of string theory as a theory of everything, there is a similar divide over whether string theory is progressive or degenerating in the Lakatos sense, because string theorists are doing interdisciplinary research in fields like quantum information science and condensed matter physics, with Sabine Hossenfelder on one side and Peter Woit on the other.
A strange venue for such a discussion when I can’t see more than a handful of people tuning in, and one of them has made his commitments extremely clear: Hypothesis H.
Quantum field theories and string theories are fundamentally mathematical objects, and they do not inherently say anything about whether a particular theory holds in the real world. While Hypothesis H might be true in the mathematics for whatever M-theory does end up being developed (and the mathematics alone is reason to continue research on string theory), that says absolutely nothing about whether it actually true in the real world at a fundamental level.
It is much more likely from my point of view that any real world evidence for a string theory model is much more likely to come from some condensed matter system in a laboratory rather than at a fundamental level in high energy physics.
Thanks! (And I had added Karch’s talk earlier today.)
Let’s try to equip each talk with the main keywords, hyperlinked to nLab entries, as far as possible. That will make the list so much more useful to readers.
Here for Sever’s talk I added:
on Wilson line-quantum observables in 3d Chern-Simons/matter-theories (such as the ABJM model)
Oh, I see that we also have an entry bosonization, but it\s just stub for the time being. Still, I’ll add the link.
Honest question: when does one stop doing string theory/M-theory, and start just doing more general QFT with a side serving of string-inspired content? I get that fields move and change focus, and one can’t be prescriptive, but I’m genuinely confused why for example things like Witten’s talk could be described as ST (really not trying to pull out a straw man here, but those are the only slides I’ve looked at so far). I view what Urs does as genuinely still string/M-theory, despite not being stuck with 90s techniques, since it’s about the actual membranes/charges/content of the same idea. I think that more people in string/M-theory really should pay attention to what is being done with Hypothesis H, it’s one of the coolest things I’ve seen in that space for a long time.
It’s a shame Urs Schreiber was never invited to Strings 2022 (or any of the past Strings conferences) to speak about Hypothesis H. Instead we get talks on topics completely unrelated to string theory such as experimental searches for dark matter.
Looks like discussion on Strings 2022 has moved over to this page; I’ll copy my second comment over to this page as well:
I fail to see how, for example, Edward Witten’s talk An Algebra of Observables for de Sitter Space, or Daniel Harlow’s A theory of the black hole interior, or Maxim Pospelov’s Dark matter identification efforts, or Amit Sever’s Line Operators in Chern-Simons-Matter Theories and Bosonization in Three Dimensions are string theory/M-theory. If those topics are string theory/M-theory, then we have redefined string theory/M-theory away from the historical definition as “a theory of force and matter unification” to mean something more like “condensed matter physics + astrophysics + quantum field theory + quantum gravity”.
I see nothing wrong with doing research in condensed matter physics or astrophysics or quantum gravity or quantum field theory with the goal of eventually defining string theory/M-theory using the knowledge gained from the research in these fields, but none of these topics are actually string theory.
As for Urs Schreiber’s previous comment:
What is surprising and somewhat ironic is that of all the vistas of non-perturbative string theory that Duff showcased in the last section of The World in Eleven Dimensions it is solely the one very last contribution in that book (holography, p. 492) which ends up utterly dominating the academic sociology of the field.
But holography is an instance of open/closed string duality on branes, and that’s very much what string theory is all about ever since it’s “second revolution” in the second half of the 1990s.
The nlab’s own article on holography states that holography is not merely “an instance of open/closed string duality on branes”, but rather a property concerning the partition and correlation functions of certain quantum field theories.
The fact that the vast majority of the string theory community has moved almost entirely into holography, and now quantum information science and quantum field theory, as indicated in this discussion in Strings 2021 between Vafa and Witten, is rather an indictment of the current state of the string theory program as the unified theory of all the forces and matter, regardless of whether one supports or opposes the notion of “string theory as the unified theory of all the forces and matter”. There is also this talk by Nima Arkani-Hamed at Strings 2021 which has a similar argument, that the string theory community is making a big mistake by pursuing the current path it’s taking right now.
Edit: That Urs Schreiber’s own work with Hypothesis H in string theory/M-theory gets ignored by the string theory community in favour of whatever trendy work well-known figures of string theory community, such as Witten, have been doing, even if Witten’s and others’ work has no relation to string theory at all, is yet another indictment of the string theory community.
The community focused its efforts mostly on holography in the past 20 years, and seeing how the ideas in holography has reached the end of its usefulness in actually contributing to progress in string theory/M-theory, they have decided to de facto give up on string theory/M-theory and see where holography could be applied in other fields, rather than retracing its steps backwards and finding other routes to progress in string theory/M-theory as indicated in Duff’s book. Witten himself admitted to Vafa in the Strings 2021 talk linked above that all this work on quantum information was only a mere hope that someday this might be useful to string theory, as he’s run out of ideas with holography actually applied to string theory.
In #23 David R. admits to be
genuinely confused why for example things like Witten’s talk could be described as ST
Witten’s 2022 talk, together with the preprint arXiv:2206.10780 that it’s based on, is a contribution to an intense 20+ year ongoing conversation in the ST community on how to see “de Sitter vacua” in the theory, concretely on how to understand them as (generalizations, maybe, of) more well-understood holographic brane constructions. It looks all field theory in this contribution, since they claim there is fine print in the QFT target to be reproduced, which previous work on “de Sitter holography” has not appreciated.
I am not going to defend the focus on this question (am with Duff in finding it premature to worry about a would-be prediction of a theory that is not developed to the point of making this prediction) but the string theoretic motivation that drives people in pursuing this is hard to overestimate. It originates in the shock the community experienced right at the turn of the millennium, when they were arguing that ST predicts (or “prefers”) vanishing cosmological constant (cc)
(later called Witten’s Dark Phantasy) at a time when the measurements of type IA supernovae by Riess et al. & Perlmutter et al. had already been made and just months before their alleged implication of a positive cc (hence of an observed “de Sitter vacuum”) went viral (as one would say today, see the references here).
Ever since – and in ironic contrast to what the public domain would start to chant was lacking – the cosmo+pheno sector of the ST community began scrambling to salvage what they perceived as the first prediction of ST having been experimentally falsified. The KKLT model and the debates around it, the “landscape” debate, the “de Sitter holography” efforts are all repercussions of this millennial shock in the ST community. That’s the tacit backdrop of Witten’s talk at Strings 2022.
Re #24:
In heroic defiance of cringyness, and besides mentioning my talk at StringMath2017 (which led up to Hypothesis H), I’ll briefly reply to this by highlighting one point:
Our previous main proposal, before Hypothesis H, namely that the Green-Schwarz mechanism is about higher non-abelian gauge field theory, took 10 years (see the references here) to be appreciated by ST community members, and it looks to me like most of them are still wrapping their mind around the notion of a 2-group (while publishing about them, nonetheless).
I am not going to defend the focus on this question (am with Duff in finding it premature to worry about a would-be prediction of a theory that is not developed to the point of making this prediction) but the string theoretic motivation that drives people in pursuing this is hard to overestimate. It originates in the shock the community experienced right at the turn of the millennium, when they were arguing that ST predicts (or “prefers”) vanishing cosmological constant (cc)
- Edward Witten, p. 7 of The Cosmological Constant From The Viewpoint Of String Theory, lecture at DM2000 (arXiv:hep-ph/0002297)
(later called Witten’s Dark Phantasy) at a time when the measurements of type IA supernovae by Riess et al. & Perlmutter et al. had already been made and just months before their alleged implication of a positive cc (hence of an observed “de Sitter vacuum”) went viral (as one would say today, see the references here).
Ever since – and in ironic contrast to what the public domain would start to chant was lacking – the cosmo+pheno sector of the ST community began scrambling to salvage what they perceived as the first prediction of ST having been experimentally falsified. The KKLT model and the debates around it, the “landscape” debate, the “de Sitter holography” efforts are all repercussions of this millennial shock in the ST community. That’s the tacit backdrop of Witten’s talk at Strings 2022.
Interesting, I wasn’t aware of this before. If this is the case, then it does change my viewpoint on the whole stagnation and decline in string theory debate: it’s entirely a consequence of the ongoing debate over the validity of portions of the standard model of cosmology, such as the cosmological constant, due to tensions between experimental evidence and the standard model of cosmology, such as the Hubble tension, the $S_8$ tension, the KBC void, and the various dipoles appearing in the CMB, the Hubble constant, supernovae data, and quasars.
Ironically, this does actually strengthen my more general point of view that current research in string theory isn’t really contributing to progress in string theory, since personally I find it more likely that in the next 10 years we’ll see a revolution in cosmology which would overturn fundamental assumptions of the current standard model of cosmology, such as the validity of the FLRW metric in the late universe in cosmology, completely revising all of cosmology and rendering the cosmological constant completely superfluous to whatever new standard model of cosmology gets developed. If this does come to pass, it would also mean that whatever research done in string theory to make it compatible with the cosmological constant would also be rendered superfluous.
From that Duff interview, concerning the role of mathematics in M-theory
(20:03) And its a very severe straightjacket: We can’t just dream up any old thing and expect it to be mathematically consistent, or consistent with our knowledge.
Then
(20:21) As you and your colleagues are aware, sophisticated mathematics is becoming more and more important in understanding M-theory; and it is going to require the kind of mathematical approaches that you are doing.
To cut string theorists a little slack, it’s not every physicist that can meet their own needs by writing foundational work in areas of pure mathematics, such as Equivariant principal infinity-bundles, guided by their own (modal) variations of a very recent breakthrough in logical foundations (HoTT).
Einstein had no need to devise a new geometry, and especially not a new logic.
Re #25:
Madeleine admits to
fail to see how, for example, Edward Witten’s talk An Algebra of Observables for de Sitter Space, or Daniel Harlow’s A theory of the black hole interior, or Maxim Pospelov’s Dark matter identification efforts, or Amit Sever’s Line Operators in Chern-Simons-Matter Theories and Bosonization in Three Dimensions are string theory/M-theory.
$\,$
On Witten’s talk: This is now explained in #26.
$\,$
On Sever’s talk:
These “Chern-Simons/matter theories” are behind the BLG model $\subset$ ABJM model for coindent quantum M2-branes. This is perceived as one of the most striking developments in ST since the “second string revolution” in 1995 – whence called the “membrane mini-revolution”.
As a result, just as
so
$\,$
On Harlow’s talk:
It is certainly true that the field of holographic entanglement entropy and holographic quantum error correction is taking but hints from string theory to then progress fairly unconstrained by the burden of a fundamental theoretical framework, allowing themselves to toy around with tools and concepts in a more free-wheeling fashion. But conversely, since string theory does constitute the fundamental theoretical framework for holography (which I highlight in contrast to a sentiment which I sense in some of your comments) one feels – and this is what drives the ST community interest here – that whatever noteworthy being figured out about holography as such is conversely a hint about string theory. And interesting it certainly is what Harlow et al. have been achieving here (starting with their now famous HaPPY code, following their string theoretic arguments in Bulk Locality and Quantum Error Correction in AdS/CFT (arXiv:1411.7041)).
(Incidentally, we feel that we see how the holographic codes emerge from Hypothesis H, this is briefly hinted at here. But that’s for another day.)
$\,$
On Pospelov’s talk:
Yeah, it seems somebody around the organizers is deeply interested in stringy astro-phenomenology. The narrative that string theory provides natural dark matter candidates (starting but not ending with the LSP) was a strong one in the past, and I’d expect that’s driving the organizer’s decision here. But it would certainly help if the invited speaker would try to connect to that somehow. (I haven’t watched the talk recording, though).
I have added two more items to the entry:
on generalized G-structures and exceptional generalized geometry of flux compactifications and in AdS/CFT:
and on n applications of AdS/CFT duality to many-body quantum systems, such as to high $T_c$ superconductivity (AdS/CMT duality) and to QCD (AdS/QCD duality:
Also, I have adjusted the first lines of the entry (venue and topics).
Re #26 I slightly resent the implication of the “admits to be”, but oh well, you can take me as I come :-)
If this paper (thanks for the reference!) didn’t have Witten’s name on it, it could have been marketed as a contribution to pure axiomatic QFT, rather than a piece of string theory, that’s all I meant to indicate. Your comments are indeed useful to explain to outsiders what the insider mindset on this stuff is, and the implicit understanding of how this stuff applies.
Honest question: when does one stop doing string theory/M-theory, and start just doing more general QFT with a side serving of string-inspired content?
And this was the real question I had, which I’d still like to know about, not commentary on my ignorance of insider string theorist knowledge :-)
that really depends on what one’s definition of string theory is, because the term “string theory” itself is ill defined in the theoretical physics community at large.
In one extreme, string theory is just bosonic string theory + supersymmetric string theory as studied in the 1990s, and very few people are studying that stuff anymore. In the other extreme, string theory is simply whatever the self-identified “string theory community” does, regardless of whether the research has anything even remotely to do with string theory.
Urs Schreiber has a definition that lies between the two extremes, but ask a few other string theorists and non-string theorists and they would probably have a different demarcation for the border between string theory and not string theory.
added pointer to today’s
on supersymmetry breaking of D=4 N=2 SYM to confining QCD with adjoint fermions.
Scott Aaronson wrote this on his most recent blog post:
AdS/CFT originally came out of string theory, but then notoriously “swallowed its parent,” to the point where nowadays, if you go to what are still called “string theory” meetings, you’re liable to hear vastly more discussion of AdS/CFT than of actual strings.
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