The past couple days the YITP at Stony Brook has been celebrating its 50th birthday. It was started back in 1966 by C. N. Yang and has been an active center for theoretical physics ever since. The ITP at Stony Brook was as some point renamed in honor of Yang, now it’s officially the “C. N. Yang Institute for Theoretical Physics”. I was a postdoc there in 1984-87, when it was just the ITP, and Yang was still the director. I had been hoping to go out to Stony Brook for at least one day of the event, but unfortunately other things have kept me here in New York.

Luckily, with today’s technology one can watch the talks online (see here) and follow what happened at the conference. I’ve watched a few of the talks, and they give a good survey of the kind of work that has been going on at the institute over the last 50 years. One aspect that isn’t emphasized in the talks (although there’s a little bit in Fred Goldhaber’s talk) is that the institute is in the same building as the mathematics department with, at least back in my day, some physicists and some mathematicians even having offices nearby on the same floor. Being able to talk to and learn from some great mathematicians (soon after Yang, in 1968 Jim Simons came to Stony Brook and brought together a world-class mathematics department) was a big influence on me during my postdoc years. These days, with the Simons Center for Geometry and Physics, Stony Brook is one of the great centers of mathematical physics.

The last talk of the event was a public talk by Ashoke Sen on What is String Theory? (slides here), one which made me think that maybe it wasn’t a bad thing that I hadn’t made it out to Stony Brook, since I might have been there for this. Sen’s talk was a depressing compilation of ancient hype and misleading claims about string theory, with the standard multiverse excuse for why it predicts nothing at all about particle physics.

My time at the ITP coincided with the early years of this kind of string theory hype, which got started in late 1984, about the time I got there. By my last year there (exactly 30 years ago, 1986-87), everyone in the physics community had already been subjected to a couple years of this kind of thing, so much so that Ginsparg and Glashow had published in spring 1986 their Desperately Seeking Superstrings article, noting that

…years of intense effort by dozens of the best and the brightest have yielded not one verifiable prediction, nor should any soon be expected.

They worried that

Contemplation of superstrings may evolve into an activity as remote from conventional particle physics as particle physics is from chemistry, to be conducted at schools of divinity by future equivalents of medieval theologians.

which many at the time thought was kind of harsh, but in retrospect looks quite prescient. I doubt that even they thought that anyone in the physics community would sit still 30 years later to listen to a talk like Sen’s.

My own attitude at the time was that superstring theory was just one in a sequence of fads that had gotten the attention of particle theorists, with one to two years the usual decay time for such things. So by 86-87, I figured this one was now past its sell-by date and would soon be on the way out. How wrong I was.

Peter,

Am I wrong that string theory was kind of on the way out, not in 87, but by the early 90’s? As I sort of remember it, there were major issues with various singularity sort of issues, and then Witten figured out ways around them, and things took off again, getting much worse when Malcedena came along. I of course never knew the details, being a mathematician, but I followed it a little since I knew Witten as a mathematician, a very good one.

Pardon my sense of humor Peter but if string theory died out long ago, you wouldn’t have your book, your blog, and your readers. In this other sector of the multiverse, who might you be in 2016?

Jeffrey M,

Interest in string theory was starting to die down in late 80s, early 90s (and during a lot of this period Witten was working on TQFT/Chern-Simons, topics not related to string theory). M-theory in the mid-90s really revived and changed a lot the nature of what string theorists were doing. It didn’t at all though address the problems of connecting string theories of unification with reality.

Tim Nguyen,

An interesting question. Quite likely I wouldn’t have a blog or popular book, maybe my book about QM and math would have been finished long ago (instead of maybe next week…). I’d like to think that in such a universe we’d have learned a lot more about quantum field theory by now, and I’d hope about questions that always have motivated me. So, I think I’d be much less well-known, but maybe much more content…

* I’d like to think that in such a universe we’d have learned a lot more about quantum field theory by now.*

I don’t really understand this claim. You can say whatever you want about string theory as a model of particle physics. We haven’t had any progress in that subject since the 70s; indeed, any progress beyond the Standard Model was at best premature. But it seems odd to me to dismiss what we’ve learned about QFT by studying strings, just because you find it unappealing as an approach to particle physics. The study of string theory, especially after 1995, has been the single most fruitful source of new toy models, new mechanisms, and new ideas in QFT.

Peter, while what you claim about interest in String theory declining in the late 80s and early 90s is true, it doesn’t tell the whole story from the information on page 20 here: https://workshops.ift.uam-csic.es/files/205/Strumia.pdf

There’s a huge x10 jump in interest beginning in 1984 after the first String revolution, falling sharply to half this level in early 1990 and remaining fairly constant up to early 2000.But the general picture is a decline, as you say, compared to its glory days of 1986.

A.J.

I’m not dismissing what has been learned about QFT as a byproduct of string theory, I’m just pointing out that, if effort devoted to string theory had instead been devoted directly to questions about QFT, quite possibly we’d have learned more about QFT. Making QFT research an appendage to string theory research means that certain aspects of QFT have gotten a lot of attention and made progress (e.g. 2d CFTs), whereas other questions about QFT have gotten little attention, because they have no connection to string theory.

As an example of what I mean, I was referring above to the amazing breakthroughs in our understanding of QFT that Witten came up with (especially Chern-Simons, TQFTs) during the late 80s, early 90s, many of which had nothing to do with string theory. What if there had been no M-theory “revolution”? Yes, you would lose all sorts of things that came out of that, but perhaps the QFT research directions that people followed instead might have been even more interesting. We’ll of course never know.

John McAllison,

I think that slide does a good job of measuring the popularity of string theory. It was at its height in 85-86, reached a local minimum around 1994, revived for a while, and has been steadily decreasing since 2000.

Peter,

It’s true (by definition, really) that when we learn something about QFT by working on string theory, we can understand it independently of string theory, although usually at some cost in intuition. (Sometimes we can even reduce it to something mathematicians can work with.)

But just because something is logically independent of X, doesn’t mean we’d have come up with it without having worked on X. Witten was working on topological QFTs because he was looking for simplified models that exhibited background independence, so that he could better understand string theory! His first paper on the subject, “Topological Quantum Field Theory”, is quite clear about this; he even says straight out that the core arguments should be familiar to string theorists. Other lines of inquiry on topological sigma models and mirror manifolds are explicitly string theoretic. The 1989 Chern-Simons theory paper is something of an odd man out, since it’s a Schwarz-type TQFT and because he was trying to write something mathematicians could digest. (But it didn’t take long for string theoretic work to spark further developments in Chern-Simons theory, like the connection Gopakumar-Vafa invariants.)

Likewise, the Seiberg-Witten revolution in differential topology was really spin-off of spin off of non-topological string theory calculations. S&W were trying to understand dualities in string theory, and they came up a calculable model of 4d confinement. To my mind, that’s of far greater importance to physics than any of the topological baubles we mathematicians get distracted by.

The things you’re suggesting might have been better to study than string theory, came from string theory.

Note: I’m not advocating making QFT research an appendage to string theory research. There’s a lot of good stuff out there that didn’t come from string theory. But I think it’s important to dismiss the origins of ideas, and it looks to me like a world where we didn’t discover string theory is just a world where we don’t know as much.

Heh. I meant to say ‘not to dismiss the origins of ideas’, but my inner mathematician interfered.

AJ,

Your claims about history really are just not true. I was there at the time, and later I spent a lot of time carefully researching the details of this history before I wrote about it in my book. One place where Witten tells the story in his own words is here:

http://www.ims.cuhk.edu.hk/~ajm/vol3/3_1/witten.ps

Note that there’s nothing about string theory there. Yes, this was (87) exactly the period when it had become clear that initial hopes for string theory weren’t working out. Witten was undoubtedly hoping that the ideas about QFT he worked out in the TQFT paper would lead to some new insight about string theory. The flow of information though was opposite to the one you suggest: he wasn’t at all using ideas from string theory to find the TQFT that Atiyah had suggested existed (based on Witten’s ideas about supersymmetry and Morse theory, applied to the space of connections). Once he had found the right TQFT undoubtedly he was hoping it would help him overcome the roadblock he was facing in string theory (it didn’t).

As for his Chern-Simons paper, sorry, that had nothing to do with string theory either (although it did have to do with the WZW cft). The idea that that came from string theory, but Witten just didn’t mention this in his paper because it was aimed at mathematicians is nonsense.

Am awaiting LMMI’s always informative questions so I can glean more from the discussion. PS Apparently, Peter, we overlapped there at Stony Brook–tho I was not in the ‘tower’ but in the dungeon labs.

It’s not surprising that string theory isn’t mentioned. Witten says explicitly in the linked article that he’s leaving it out of the discussion, presumably because he’s writing for an audience of mathematicians. Then he skips over the details of how he came to write down the twisted N=2 theory, saying only that he had the ‘good luck’ to notice how to do it. (He similarly elides the story of how he & Seiberg had the ‘great good fortune’ of looking at electric/magnetic duality in N=2 theories…) So, no, I don’t think that article gives a complete picture of what was in his mind and motivating him when he cooked up the Donaldson theory. Fortunately, we do have the original article, where he points out that the core arguments are analogous to ones already known in string theory. Forgive me if I take Witten’s word here.

You can divide TQFT from string theory logically, but you can’t split up the intellectual histories of the two subjects. I don’t even know why you’d want to, given how much explanatory power you lose.

Just realized I’ve been through this same discussion before, with Lubos Motl. For those who care, see

http://www.math.columbia.edu/~woit/wordpress/?p=99

Hi, paddy,

I got nothing. I’m just astonished at the “Desperately Seeking…” article. If they added a paragraph on the 10^500 vacua, seems like it could have been written 30 minutes ago instead of 30 years and still been quite topical. Philosophically, nothing’s been settled, despite the best efforts of the Bayesians to make it seem otherwise. Plus ça change…

One correction to the history you give in your link: You say that by ’89, Witten “has completely abandoned the idea of relating Jones polynomials to topological sigma models” and that “New ideas about relations between branes, topological strings, and Chern-Simons appeared about ten years later”. In fact, the next big step in the story comes in ’92, with Witten’s “Chern-Simons Gauge Theory As A String Theory”, where he explains how to realize Chern-Simons theory as the spacetime physics of a topological string theory, more or less as he’d anticipated in the first TQFT paper. That’s only a 3 year gap, which doesn’t seem like much to me, given that it’s a substantially more difficult paper.

“I knew Witten as a mathematician, a very good one.”

I was actually fortunate enough to have Witten come to my talk on quantum Yang-Mills at the IAS earlier in April:

https://www.youtube.com/watch?v=3lEgEGCH2cg

of which are more up to date and entertaining account of my work can be found here:

https://www.youtube.com/watch?v=hHXavKP6EmI

I was a bit surprised that the only question Witten had during question time at the end of my talk was matters pertaining to higher genus – a question only a mathematician (or a string theorist?) would ask! Ironic, since I myself as mathematician/physicist, the motivation behind my work was much more along the lines of fundamental physics/QFT and I was hoping Witten would have something to say about those issues.

Based on this isolated experience, I suspect speculations about Witten’s true motivations may not be so cut and dry.

How do you think Montonen-Olive duality would have fared without the work of Sen, whom you just managed to be breathtakingly disrespectful to.

student,

I think Montonen-Olive duality would have fared fine without Sen. And what’s breathtakingly disrespectful here is not my (accurate) characterization of his talk, but his decision to deliver a talk full of misleading hype and pseudo-science to the audience at Stony Brook.

Dear Peter,

echoing a bit here what the commenters ”student” and AJ wrote. You know I usually do not comment in this forum, but the discussion is interesting in this case.

–About Ashoke Sen’s talk: true, the first part of his seminar is a bit disappointing. Except for the analogy with the phases of water, there is not much. But may be that is his view of that part of String Theory. If one reads the second part, the thing takes a much more interesting perspective. In particular, Sen discussed the virtue of the black hole as an ideal system. This lead to remarkable progress. It is a counting problem that ‘knows’ about quantum gravity. Far from trivial are Sen’s and collaborators papers on this topics.

I just felt that your comment about his talk was unfair. May be I am biased by the fact that knowing Sen, having discussed with him in few occasions, I clearly have the perception that he is a very deep thinker, who truly cares for his research and the truth in it. Aside from a very nice person. I know I am mixing things here, so just wanted to stress that the second part of his seminar was much more insightful.

–About QFT and all we missed to learn because of the efforts being focused on string theory: You are saying in one of your responses to the commenter AJ that:

” I’m not dismissing what has been learned about QFT as a byproduct of string theory, ”

On which we agree. The bit about ”many more things about QFT would have been learnt if the effort on strings had been dedicated to QFT” I think i disagree. Of course, we do not know and we cannot know. But, I know you appreciate the fact that the theory of strings, dealing with very symmetric systems, has a high chance of striking a discovery.

There are various examples in ”stringy times’ ‘ of QFT progress that happened ‘independently’ of String theory (though many of the discoverers are string people): Seiberg duality, the Seiberg-Witten solution are such examples (though not so good, as there is a stringy taste to them). Importantly, these ideas found a very nice and intuitive realisation in stringy language (brane set ups, etc). Other important advances in QFT—like the Maldacena conjecture–seem harder to come by if one is not working on strings.

All I am trying to say (a bit obvious, I believe) is that being so symmetric, String Theory suggest ideas that then might find interesting applications in QFT in general. It ‘geometrizes’ the Physics problems. I believe we will agree on this virtue of the theory of Strings.

About the String Theory being a description of physical Nature, I am saying nothing here. Just about its ability to struck on interesting aspects of QFT in general.

thanks for the posting and the links

adrian,

The problem is that I don’t think there’s anything meaningful one can say about the intertwined relationship of string theory and QFT research in a sentence or two, and attempts to do so lead to stupid ideological posturing, not insight. The problem starts with the fact that “string theory” is not a specific thing (in particular, you say it is “very symmetric”, but we don’t know what the symmetries of non-perturbative string theory might be), but a name attached to a huge area of research into some very disparate things. There are lots of interesting specific things one could discuss, but just arguing “string theory” this or “string theory” that doesn’t capture anything non-trivial. My comments about this were about two very specific advances in QFT made by Witten in 1988 where the situation is rather simple: they had little to nothing to do with string theory (under any sensible definition of the term).

I’ve never met Sen, and everyone I know who has tells me he’s a very nice person and a serious scientist and I’m sure they’re right. Of course I don’t think his plan was to write a talk full of misleading hype and pseudo-science, and the talk he gave wasn’t much different than a hundred other similar ones delivered over the last 30 years, many of which he’s probably sat through himself and thought they were all right. That he is likely not aware of them does not change the problems with the talk.

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Hi L(N)MMI,

I read that 30 years old article by Ginsparg/Glashow article many years ago (and god don’t I feel old). Not sure when I read it though I suspect via a PW link at least a decade ago. But thanks to you and PW I have reread it. ‘Tis somewhat prophetic, eh? (Glashow was my favorite professor during my brief foray into HEP-th 40 years ago.)

Somehow I missed that one. Prophetic indeed. Like Cassandra, unfortunately.

In nearly a decade of my occasional visits to “Not Even Wrong” I feel, for the first time, sufficiently provoked to key in a comment. Ashoke’s talk at YITP 50 is a model of clarity and comprehensiveness, especially for a public lecture. Even those who are dismissive of String Theory will have to grant that. Anyone who knows Ashoke even faintly knows that he cannot be associated with the word “hype” in any sense of the term. He, as someone commented above, is undoubtedly a deep thinker. But beyond that he is an unassuming and self-effacing person of a truly rare kind. Only other physicist with similar qualities who comes to my mind is perhaps Jeffrey Goldstone – my teacher at MIT nearly four decades ago.

Ashoke believes that potentially deep theories must be explored thoroughly to see what they have to say about the world. It is a fortunate thing that he has decided to deploy his remarkable talents to this end, as must also be said about Witten. Everyone knows that the twin goals of String Theory – understanding the success of the Standard Model and arriving convincingly at Quantum Gravity – have not been realized so far. I am sure leaders of the field including Ashoke are more aware of this situation than anyone else. One may remember Witten’s assessment of the difficulties when he remarked nearly three decades ago about the fortuitousness of 21st century physics and 22nd century mathematics falling into the lap of 20th century.

There may be many string theory enthusiasts who may be prone to hype. But names like Ashoke Sen and Edward Witten should not be dragged into the mud.

Ravi Sinha,

I don’t agree at all that the lecture was “a model of clarity and comprehensiveness” (for one thing, comprehensiveness would require explaining the problems with the ideas one is promoting). Why do you engage in hype as an argument that someone else isn’t?

You seem to think that criticizing the content of an academic lecture is a personal attack on someone, “dragging their name through the mud”. I think that my characterization of this talk is accurate, and that it has nothing at all to do with Sen’s personal qualities, which are quite possibly highly admirable. I also don’t know why you bring Witten into this since he wasn’t mentioned. I have written critically about things Witten has said in quite a few places, but from everything I’ve written it should be clear this is not inconsistent with great admiration for him personally and intellectually. That I’m “dragging his name through the mud” is a ridiculous accusation

Smart, nice, unassuming people can be wrong about things, and, at times, this needs to be pointed out. That’s all I’m doing here.

I was looking at Sen’s slides. Two things. He seems to describe compactification as the shrinking of 6 dimensions. Is that actually what physicists mean by compactification? It’s not correct mathematically, mathematically compactification has nothing to do with the diameter, it’s just whether every open cover has a finite sub cover. Am I misreading the slides? Is he saying that we shrink the dimensions by turning them into circles? But the circles could still be big, even though they’re compact. Second thing, he makes a big deal of ADS/CFT, and how this shows that string theory is obviously going to give us a correct quantum theory of gravity. Except ADS/CFT lives in a universe where the sign of the cosmological constant is opposite to the sign in the universe we actually live in. So how is it relevant?

Jeff M.,

Physicists don’t use “compactification” in quite the same way as mathematicians. They use this just to mean you are looking at a theory on a pseudo-Riemannian background manifold that is Minkowski space or some cosmological background times some Riemannian manifold M. M is generally assumed to have dimensions very small with respect to observed distance scales (to explain why we don’t see evidence of it). It may be smooth and compact, but also could be singular and non-compact. Typical models also add lots of other structures to M (e.g. choices of cohomology classes).

AdS/CFT solves none of the problems of string theory unification, so no point to discuss it here.

Please, keep in mind this is not a general discussion board, I don’t want to moderate such a thing.

Looked up Mencken for some solace/wisdom about democracy to sooth myself from the current national election… bumped into curious Mencken viewpoints about science, about how he trusted empiricism but was harshly skeptical of even minimal mathematical intrusion… somewhat applicable to the everlasting string theory back-and-forth…. Mencken was caustically cynical about atoms, quantum mechanics, and relativity…

https://en.wikipedia.org/wiki/H._L._Mencken#Science

I am kind of “Anglican” on the string theory of the moment… that is, I think current practitioners do respect empiricism, eventually, and are conveniently hopeful that LHC etc might find something soon in their favor.

Old topic… I see your point Peter about KC Cole.

Peter,

Sorry, didn’t intend to open a can of worms with ADS/CFT. It just really confuses me, why anyone cares about it. And thanks for clarifying about compact.

Peter,

As someone not knowledgeable enough to have an opinion of what is/isn’t a fair characterization of Sen’s lecture, perhaps a suggestion for future criticisms of such lectures would be some sort of time chart of the lecture paired with corresponding specific rebuttals to make more tangible what exactly you find disagreeable. I imagine the specific objections to string theory have not changed much over the years and so have been thoroughly discussed in the annals of this blog. Which means that you could probably just link the time frames to old threads. It would take a bit of work, but if you’re already watching the video, I think the extra amount of time would be worth the amount it would strengthen your objections. Just my two cents.

(As someone who’s written a paper/made a video critical of the way physicists do perturbative QFT, I myself made a very precise criticism of Peskin-Schroeder by highlighting specific passages and explaining what goes awry. Thus far, I’ve had no one object to this analysis and I do not anticipate anyone being capable of doing so. This is quite different than the vague “physicists aren’t rigorous” throwing in of the towel by nearly all mathematicians, which has never deterred physicists from doing what they do and has not increased mathematician’s understanding of QFT.)

I might as well illustrate precisely what I meant by a specific criticism of Peskin-Schroeder, here is a link to the video at the precise moment (the 1:11 mark):

https://youtu.be/QTjmLBzAdAA?t=1m11s

Of course, you don’t need to be as technologically fancy as I was, but a link to the video to be analyzed, lists of specific time frames, and your rebuttals would get the job done.

Tim Nguyen,

Sorry, but I’m not going to spend time doing that kind of thing. I spent a couple years writing a book addressing these issues in detail and explaining what the problems were with the conventional string theory hype. Sen is just repeating pretty much the same hype the book was aimed at. If he had a new argument, maybe I’d discuss that, but he doesn’t. No sensible person wants to read yet another explanation from me of why string theory unification has failed and why the string landscape multiverse is pseudo-science.

I should point out that references to the problem of continuing string theory hype like the ones in this blog posting are not really aimed at explaining the problem to non-experts, for that there’s the book. Knowing how these things go and from the little I could see and hear of the audience in this video, I’d suspect that physicists who had heard all this many times before made up most of the audience. In some sense what I write here is aimed at them: why do you put up with this? It’s done a huge amount of damage to your field and its credibility, why schedule talks like this, then sit there politely and listen to them?

Peter,

Of course, you know how best to spend your time rather than me. It just seems that there is enough energy spent going back in the forth in the comments that a pre-emptive investment along the lines I suggested might be worth considering. It was just a thought.

“It’s done a huge amount of damage to your field and its credibility”

Well, “my field” is mathematics and I’m actually under the impression that mathematicians are at worst agnostic about string theory, but at best, they are willing to hire them since string theory has inspired a lot of rich mathematics. I’m unusual in that I’m motivated in trying to understand QFT. I haven’t gotten into string theory because my time and energy are finite and so I’ve chosen to focus on something more grounded (in fact, it’s already risky/suicidal enough to pursue QFT as a mathematician, so I don’t need to further up the stakes with string theory).

I can sympathize with you to one extent which is that I do feel that there is a great deal of work done on mathematical “QFT” that may as well be classified as “damaging”, e.g. works in which the mathematical formalism itself supplants the substance of the subject (e.g. imagine if in learning “general relativity” one became preoccupied with tensors and how one could make them more complicated, adding more indices, making things noncommutative, invoking higher categories only for the sake for their mathematical consistency, but then left out the underlying geometry and gravity itself; the consequence is research that is much ado about nothing insofar as GR is concerned and I do find talks along these lines hard to “sit politely” and listen). One of the reasons I invested time in my videos was to provide a no-nonsense account of the mathematical accounts of QFT, one which gets straight to the point and avoids all the “damaging” detours I went through before finding my way.

As this was a completely avante garde thing to do and only undertaken recently, I don’t know how much of an influence/difference this will make. But it seems to me, as with all social/political changes, the voice of reason needs constant rekindling and repetition. I myself read your book some time ago, it was a good read, but I can’t remember the exact arguments or details any longer. Just as no two protests over the latest outrage over police violence/etc. are the same, I imagine no two “damaging string theory lectures” will be completely identical or redundant either. But if your goal is to get people to see your point of view (I imagine you desire this to some extent), perhaps creative forms of reinforcing what you’ve already claimed, along the lines I’ve suggested, might work. This is of course up to you, but it’s a suggestion that at least is backed up by what I’m trying to do in my own terms.

In any case, I suspect this thread shouldn’t degenerate into suggestions on how your blog should be run, unless of course, you are open to polling readers on this idea 🙂

I attended Sen’s lecture in Stony Brook, and while I mostly agree with you on the assessment of String Theory, I think I should share some observations I have regarding Sen’s lecture. I was quite surprised at the turnout, since it wasn’t really widely promoted (e.g. the poster for the event was only distributed a few days before the event). There were at least 300 people in the audience, including people from on and off campus. I think even the university president was there. What also surprised me was the almost-rock-star status of Sen in the eyes of some participants. Most of the audience seemed in awe of him, never mind that most probably didn’t understand what he’s talking about (made worse by his heavy Indian accent), almost nobody left in the middle of the lecture, and at the end I even saw people asking Sen for autographs! As a physicist myself I have to say I’m pretty impressed but also baffled. Granted Sen is a rather famous theoretical physicist in his field, but even some physicists may not know him outside his field. I guess we have Yuri Milner and his glitzy Breakthrough Prizes to thank for elevating Sen to physics superstardom in the eyes of the public…

Ming,

Thanks for the report. From the video one couldn’t tell what the size of the audience was. It is remarkable that one can get that large a crowd to come hear a not so well known string theorist give a promotional talk indistinguishable from many others given over the past 30 years.

It’s amusing for you to say that a very highly cited Dirac medalist physicist to be not so well known. When non physicists writing nay saying books on physics can be popular, it may be better to remain not well known. But nevertheless… It’s amusing to see your comment

Boundary graviton,

The “not so well known” referred to “not so well known” to the public, which was the audience for this talk. I think it’s quite accurate to say that Sen is not well known to the public, certainly in the US. The same is true of the Dirac medal.

Actually, I think the same is even true for physicists in general, leaving aside theorists, who would generally know about him.

Right. I get the sense which you told it now. Stony Brook is where he did his PhD. That might have contributed.

*in which

By the way, when Maldacena visited India, lectures were filled to full capacity. Same was the case with Witten but Witten is much more known to the public perhaps.