Enjoying a vacation on a Caribbean porch, and just had a couple hours to kill with good internet access. For some reason I spent part of them listening to the summary panel discussions at Strings 2025, which just ended today.
Honestly, this was just completely pathetic. The whole thing was run by David Gross, who at 83 is entering his fifth decade of hyping string theory. Besides the usual claims that the field is doing great, he had to announce that they’ve been unable to find anyone willing to organize Strings 2026, so there is some chance this would the last of the lot.
There were three panel discussions, involving nineteen people in addition to Gross. No one had any significant progress to report, or anything optimistic to say about future progress. It was mostly just an endless rehash of discussing the same basic problems the field has been obsessed with and made no progress on for 25 years (e.g. how do we do dS/CFT instead of adS/CFT?).
The suggestions for the only ways to make progress were often naive ideas about giving up fundamental principles of quantum mechanics (“maybe we should give up on having a Hamiltonian”) or getting something from nothing (“maybe making it a principle that the state space is finite dimensional will work”).
I honestly don’t understand why people continue to participate in this and expect anyone to take them seriously.
Update: The next posting I started working on accidentally got “published”, although I had just started it. Ignore the various automatically generated announcement of that. Will try to get the real thing finished and published within the next couple days.
Update: The accidentally published start of a post was a failed experiment. It’s just too hard to write latex with commutative diagrams and things in WordPress and I don’t want to spend my time struggling with that. I’ll go back to working in standard latex, provide a link to a pdf of a draft paper when it’s ready.
Update: The Empire strikes back against the critics, on Youtube here and here.
This foolishness just goes on. I know DG very well we had a common thesis advisor Geoff Chew.
As i paraphased Sir Winston Churchill on the RAF in the battle of Britain.
” Never has so much been accomplished by so few that fought so valiantly”
String theory
Never has so little been accomplished by so many who have toiled so long”
I have pissed off a lot of people with my comments.
I don’t give a damm I am an old physicist ( just celebrated my 88th birthday) living in an island in WA state.
Best as always
Ivan Muzinich
Ivan Muzinich,
What I find truly depressing here is not that someone with four decades invested in this won’t stop, no matter how ridiculous it gets, but that so many much younger people have signed up for this. Watching 19 of them sit there, and nod their heads at nonsense, with not one of them daring to even suggest the possibility of the obvious, that things are not working out at all is about as depressing as the rest of the beginning of 2025.
Dear Mr Woit,
You are hurting yourself and life is short.
The 2000th post on your blog should serve as a wake-up call: it’s time to stop commenting on the non-news of String Theory (actually, this would have been reasonable already 15 years ago) and discuss/focus on interesting things : L-functions, motives, Langlands program, number/function field analogy, analytic stacks, …
Friendly,
Anonymous reader,
Excellent advice, although what I’m most fascinated by is connections between these topics and QFT. These are unfortunately extremely poorly understood, so writing about this sensibly is difficult. For the relatively well-understood pure mathematics, someone much more expert than me should be doing the writing.
I do hope in coming weeks to get some things written about topics I do understand, maybe starting with hyperfunctions and lot more about twistors.
@Peter Woit: Jan. 10, 2025, 3:46 comment “… lot more about twistors …” Keep in mind that Edward Witten has stated that he has “worked on the specific subject of twistor theory quite a lot”.
https://pubs.aip.org/physicstoday/article/69/5/12/415524/Highlighting-the-usefulness-of-string-theory
Should there be a written, published debate on the role of twistor theory in the foundations of physics with Woit debating some prominent string theorist?
On that note on twistors, it would be great if you could write a vignette on their application in the representation theory of the conformal group in general D dimensions. Can’t find a good reference for this.
Perhaps slightly off-topic but I thought it might be worth mentioning, the Handbook of Quantum Gravity was finally published in physical/electronic copies, with the pdf coming in at 4,315 pages. A breakdown of the contents by topic:
Part I Effective Quantum Gravity – 7 topics
Part II Perturbative Quantum Gravity – 9 topics
Part III Asymptotically Safe Quantum Gravity – 9 topics
Part IV Nonlocal Quantum Gravity – 9 topics
Part V Supergravity – 12 topics
Part VI String Theories – 15 topics
Part VII Causal Sets – 11 topics
Part VIII Causal Dynamical Triangulations – 10 topics
Part IX Loop Quantum Gravity and Spinfoams – 14 topics
Strings and allied fields still make 2/3 of the largest parts of the book…
Peter,
fundamental physics must answer three hard questions:
– What is the origin of the elementary particles with their three generations?
– What is the origin of the gauge interactions with their Lie groups?
– What is the origin of the coupling constants and elementary particle masses?
Even the most die-hard string theorists I know always avoided the topics.
But aren’t the answers to those questions exactly the places where the treasure is buried?
The closing session was not a “summary panel.” Rather the session chairs were brought together to say a few words about their sessions and make interesting or provocative comments. The idea was to have a gentle ending and leave people with something to think about.
Constructive criticism of the scientific program — which, in my opinion, was remarkably rich and diverse — would be welcome. But, at the moment, you have not engaged at all with any of the program’s substantive content. Your post is based on a complete misunderstanding of the role of the closing session. It would be nice to correct this.
(I was one of the scientific organizers but to be clear: I’m posting here in my personal capacity and don’t speak for the conference.)
David Brown,
The problem is that there are very few people, string theorists or otherwise, expert on such questions about twistor theory. I’d guess most of those who are and are skeptical about my claims view them as too speculative, need more to back them up.
I’m working on it…
Anonymous twistor,
For a very general discussion of applications of twistor theory in representation theory, I’d recommend the book “The Penrose Transform”, by Baston and Eastwood.
Specifically about the conformal group, twistor methods are mainly about the 4d case, in particular about a certain class of representations of the double cover SU(2,2) of the conformal group SO(4,2) in Lorentz signature. These are the “ladder representations”
From the twistor point of view, these representations are on the solution spaces of massless wave equations of helicity h, which in the twistor picture are given by sections (actually hyperfunctions, boundary values of holomorphic sections) of holomorphic bundles on projective twistor space.
For those interested, you can buy a copy of the “Handbook of Quantum Gravity” for the price of \$1299 from Springer, or maybe get online through your institution at
https://link.springer.com/referencework/10.1007/978-981-99-7681-2
Among its 4315 pages, the only reference to twistors is a paragraph on page 2331 giving some twistor string reference.
Klaus,
Yes. These are the sort of fundamental problems the string theorists have basically given up on (and convinced most others that thinking about them is hopeless).
Suvrat Raju,
I don’t see how my characterization of those panels and what was said at them was significantly incorrect.
> Among its 4315 pages, the only reference to twistors is a paragraph on page 2331 giving some twistor string reference.
Not the only one, there is also a (admittedly, short) paragraph on the use of twistors in loop quantum gravity amplitudes on page 3897 😉
Simone Speziale,
Thanks!
To be clear, I didn’t read al 4315 pages, was just going by the index…
Peter, something OT. Videos of talks at Inaugural Weinberg conference at UT at https://www.youtube.com/@UTPhysics/videos
Dear Raju, can you expand on Peter’s summary of the conference, telling the substantive content? Maybe somebody found a way to detect Planck scale particles?
Peter:
You say: “I honestly don’t understand why people continue to participate in this and expect anyone to take them seriously.”
All these people care about is that other string theorists take them seriously. These are the 0nly people they need to convince to keep getting promoted, funded, cited, etc. And sadly, other string theorists probably will.
“All these people care about is that other string theorists take them seriously.”
Our head of department emphasises that when someone retires that just because they worked in X does not mean the replacement has to, because what is important changes. So seems odd they would not want to convince other physicists.
Mark,
I think the point is that if you are a “string theorist” with a permanent job, your main professional concerns are that other “string theorists” think well of you, so will provide conference and speaking invitations, accept your papers at a journal, cite your papers, positively review your grant proposals, hire your students as postdocs, etc.
That the rest of the physics community no longer thinks well of “string theorists” is of lesser importance (although this motivates for instance why Witten gives talks about “what every physicist should know about string theory”). The main downside is your colleagues not wanting to hire more “string theorists” (or replacements for colleague “string theorists” to work with you). Whether they’ll hire a “string theorist” to replace you when you retire isn’t typically a big concern.
One reason for putting “string theorist” in parentheses is that it’s very hard to know what that means these days. Part of the way the “string theorist” community is dealing with a critical attitude from other physicists is by trying to rebrand “string theory” as something much more desirable. The past ten years or so there has been a big attempt to rebrand as somehow part of quantum information and ride the quantum computation funding and publicity wave. That’s now receding and some “string theorists” are trying to find a way to rebrand to catch the AI wave.
““string theorists” think well of you, so will provide conference and speaking invitations, accept your papers at a journal, cite your papers, positively review your grant proposals, hire your students as postdocs, etc.”
As a postdoc on the job market, here I was, thinking the grad students should be judged on their own merit independently of their advisor’s influence. How naive of me.
The sociological behavior of string theorists were described long ago by Philip Abelson. See, https://www.science.org/doi/10.1126/science.144.3617.371
“As a postdoc on the job market, here I was, thinking the grad students should be judged on their own merit independently of their advisor’s influence.”
The price of a young racehorse without much of a track record depends mainly on its lineage.
Peter,
I think it’s going to be really hard for “string theorists” to catch the AI wave without writing software that actually works. Theoretical quantum computing research is held in fairly high esteem, which is why they were able to get away with doing “string theory quantum computing”. My impression is that theory in AI is much less well respected. If they do “string theory AI” without writing working software, possibly the only other people who will pay attention to them are other physicists who don’t understand AI. On the other hand, maybe this is enough to keep convincing physics departments that they’re relevant.
Peter, you said before that “science progresses one funeral at a time” principle does not work with Strings, because the string theorists are successful in training and “converting” new generation of physicists.
Yet I have a feeling (perhaps misguided) that the principle is still at work, just slower than expected. From the outside it seems that the triumphalism of string theorists is gone. It also seems that with each generation string theorists are both less enthusiastic and carry less authority with outside world (are less famous and have less commonly recognized achievements outside of strings) .
In this light the failure to find somebody who would organize Strings 2026 may be significant and not a fluke?
NoGo,
It’s true that the public perception (and general physics community perception) has changed and lots of institutions no longer are going to hire string theorists (or sponsor StringsXXXX conferences). The problem with this though is that the string theory debacle has discredited the whole subject, so these institutions aren’t just not hiring string theorists, but not hiring particle theorists (non-phenomenological) at all.
The situation though hasn’t changed at the most influential institutions in the US that I’m well familiar with. At Harvard and Princeton hiring in the theory group has been consistently dominated by string theorists for 40 years now, their youngest hires are more of the same.
Maybe the Planck quote would be more accurately about “one retirement at a time”. A place to watch is the IAS, where Witten has recently retired and Seiberg is up next. Will the IAS replace them with younger string theorists? with different kinds of particle theorists? or maybe give up on the institution’s long and glorious history in this area and hire in different areas?