This Week’s Hype

The hype campaign marches on, just three very recent examples:

Posted in This Week's Hype | 56 Comments

Something about England

Heading to Oxford today, this evening I’ll give a talk there on Unified Theories of Physics. On Saturday I’ll try to find some way to get to the HTLGI Festival in London despite a national rail strike, where I’ll give a talk on Saturday and be on two panel discussions Sunday.

I’ll post slides after the talk tonight, one theme of which will be the failure of a series of attempts to extend the Standard Model, all of which were started in the mid-1970s (GUTs, SUSY, string theory). An opinion piece by Sabine Hossenfelder appeared yesterday in the Guardian, which takes a similar point of view on the current fate of extensions of the SM, but I strongly disagree with a lot of what she has to say.

The bad theory activity she points to has been going on for decades, but in recent years it seems to me to be a lot less popular. Most influential theorists have (quietly) agreed with her that particle physics is dead. In attacking bad model building in particle physics, I think she’s going after a small group of stragglers, not the center of theoretical activity (which has problems much more worth discussing).

What I most disagree with her about though is her treatment of HEP experiment and experimentalists. Yes, one can find people who have used bad theory to make bad arguments for building a new machine, but I don’t think those have been of much significance. For more on the current debate about this, see here. At the present time though, no one is spending money on building a new energy frontier machine any time soon. Money is being spent on running the LHC at high luminosity (CERN) and studying neutrinos (US), as well as studying the possibilities for going to higher energy. All of these activities are valuable and well-justified.

The LHC has been a huge success so far, with the old claims that it was going to see extra dimensions an embarrassment which doesn’t change the science that has happened. The discovery of the Higgs was a huge advance for the field, and the on-going effort to study its properties in detail is important. Another huge advance for the field has been the careful investigation of the new energy range opened up by the LHC, shooting down a lot of bad theory. Pre-LHC, the most influential theorists in the world heavily promoted dubious SUSY extensions of the SM, making these arguably the dominant paradigm in the field. LHC experimentalists have blown huge holes in that bandwagon, in some sense by doing exactly what Hossenfelder complains about (looking for evidence of badly motivated theories of new particles). In this story they’re not the problem, they’re the solution.

I’ll be busy this week with the talks mentioned and with attending math talks in Oxford, so little time to discuss more here or do a good job moderating a discussion. So, behave.

Update
: The slides from the Oxford talk are here.

Update: Sabine has a blog entry more carefully explaining her point of view here.

Update: Some coverage of this at Physics World.

Update: More discussion of this from Ethan Siegel here, response from Sabine here.

Posted in Uncategorized | 29 Comments

Some News, Then More of the Same

Some News:

I’ll be in England later in the month, in Oxford much of the week of the 26th-30th. That week is the week of the 2022 Clay Research Conference and Workshops. The evening of Tuesday the 27th I’ll be giving a public talk on Unified Theories of Physics, sponsored by the Oxford Centre of the Institute of physics.

The 2022 HowTheLightGetsIn festival in London was supposed to be the weekend of September 17-18, but has been postponed two weeks because of the death of the Queen. It’s now scheduled instead for the weekend of October 1-2 and I’ll likely be there, participating in a couple of panel discussions.

More of the Same:

I’ve written too much here over the years about the problems with multiverse theories. For short versions, there’s also FAQ entries here and here, and a piece called Theorists Without a Theory I wrote for Inference. Seeing some recent things about this topic from people I generally agree with (e.g. here and here) leads to an uncontrollable urge to reiterate some of my arguments, so:

  • You can’t argue against the concept of a multiverse in general, dismissing unobservable universes. If you had a very successful theory based on ideas that simultaneously implied successful predictions about what you can observe, as well as unobservable parallel universes, you could get indirect evidence for a multiverse. The strength of this evidence would depend on the details of the theory, but it’s logically possible that this could be strong evidence.
  • Arguments pro or con about the “multiverse” that simultaneously engage with the many-worlds interpretation of quantum mechanics and inflationary or string theory landscape models are a waste of time. These are two completely different subjects, which raise completely different issues and have nothing to do with each other. For the rest of this I’ll stick to the second subject, ignore the first.
  • If you want to have a serious discussion on this topic, it should be about a particular model or well-defined class of models. One popular class is inflationary models. Here people often write down a well-defined model, but the problem is that it’s a toy model (e.g. no SM fields, just gravity and a hypothetical inflaton field unrelated to any field for which we have a tested theory). Another popular class is the “string theory landscape”. Here the problem is that you don’t have a well-defined model. People who work on this work not with a well-defined theory but with a list of properties of a conjectured, currently non-existent, theory (e.g. “M-theory”). There’s nothing wrong with doing this to see if you get interesting predictions about the world, which would give you some confidence in the existence of the conjectural theory. There is something seriously wrong with doing this if after decades of work you find that the list of properties you have is vacuous in terms of explanatory power.
  • It’s important to understand just how vacuous the “string theory landscape” class of models is. The problem is not just a measure problem on the space of possible universes, but much worse: one has no idea what this space is that you would like to put a measure on.
  • “Pseudo-science” is an accurate description of “string theory landscape” research. People have complained to me that it is too harsh, should only be applied to activities of people who are abusing the good name of science for discreditable purposes. Doing something because you refuse to admit failure of a scientific idea you have a lot invested in seems to me a discreditable purpose.

Update: Joe Conlon is upset that I’ll be speaking in Oxford. He objects to my credentials, but perhaps my views on his field of string phenomenology (which are shared by a large fraction of the physics community) might have something to do with it. I’m wondering if Conlon also complained about this recent Oxford speaker (video here).

Posted in Multiverse Mania, Uncategorized | 48 Comments

This and Next Year’s Hype

I normally try and avoid getting into the vast topic of the hype problem in other subjects than string theory, but a couple things I’ve seen recently make it hard to resist. So, just this once…

Quantum Computing

Michio Kaku has a new book coming out next year, called Quantum Supremacy: How the Quantum Computer Revolution Will Change Everything. The publisher’s summary tells us that quantum computing “may eventually unravel the deepest mysteries of science and solve some of humanity’s biggest problems, like global warming, world hunger, and incurable disease.” More concisely:

There is not a single problem humanity faces that couldn’t be addressed by quantum computing.

For a very different take, see The quantum computing bubble at the Financial Times, where Nikita Gourianov argues that there’s a speculative bubble going on in this field, and:

Well, when exactly the bubble will pop is difficult to say, but at some point the claims will be found out and the funding will dry up. I just hope that when the music stops and the bubble pops, the public will still listen to us physicists.

For a response to this, see a later article at the Financial Times: Separating quantum hype from quantum reality.

I think Gourianov makes an important point for physicists to keep in mind. Having this sort of hype blow up in physicist’s faces is not going to help with the credibility problems physics already has with the public due to decades of hype about non-existent breakthroughs in fundamental physics.

Nuclear Fusion

Attempts to build a nuclear fusion-based power reactor have been going on for 70 years or so. Decades ago it had already become a joke that success was always “30 years off”. One would think that because of this there would be overwhelming skepticism about new claims in this field, but there’s continual new hype all the time. The Guardian recently had a long article about The race to give nuclear fusion a role in the climate emergency. If you read the article carefully, there’s no evidence of any change on the “30 years off” front, with one expert describing magnetic confinement-based reactors as highly unlikely before “after 2050” and laser-based schemes “another 50 years to go, if at all.”

One project that has been getting a lot of press is SPARC, a collaboration between MIT and a private start-up. Their claim seems to be that they’ve got a workable reactor design all ready to go, last year finished developing the needed 20T high temperature superconductor-based magnet, and by 2025 will have a working reactor putting out more energy than goes in. Then:

On this path, how long would it take before fusion energy is on the grid?

MIT scientists and their collaborators believe that ARC — a fusion power plant that would produce electricity continuously — could be built and operating by early 2030.

This all seems highly implausible to me, but Bill Gates is putting money into the the project and I guess we’ll find out soon. For a skeptical take, see here.

About nuclear fusion, Michio Kaku tells us that:

Quantum computers could allow us to finally create nuclear fusion reactors that create clean, renewable energy without radioactive waste or threats of meltdown.

Two more items:

Getting back to the sort of claims about physics that don’t work out that I usually write about, the IAS website points to two recent items:

Update: Theoretical physicists are making a contribution to the energy crisis, see here.

Posted in This Week's Hype | 25 Comments

LHC News

I see today via the LHC Page 1 Vistar that a problem at a cooling tower will cause part of the accelerator to need to be warmed up to room temperature, putting the LHC out of business for the next 4 weeks or so.

The LHC has just been coming out of long shutdown the past few months, starting its Run 3. In the past couple weeks it has started to get up towards its full luminosity potential, with over 2400 bunches in the beam. So far during Run 3 the machine has delivered an integrated luminosity of about 10 inverse fb to each of the experiments (ATLAS/CMS). The plan for Run 3 (which is expected to last through 2025) is to accumulate an integrated luminosity of about 300 inverse fb, doubling the 140 inverse fb of Run 2, at a slightly higher beam energy (6.8 TeV vs. 6.5 TeV).

Update: Thanks to Benson Woo for pointing out to me an article today in the Wall Street Journal about plans for possible shutdowns of parts of the CERN accelerator complex this winter in case of energy supply problems due to the ongoing conflict with Russia.

Posted in Experimental HEP News | 2 Comments

Various and Sundry

A random collection of things that may be of interest:

  • September 17 and 18 I’ll be at the How the Light Gets In Festival in London, participating in discussions of the relation of math and physics, and theories of everything. I’m looking forward to the festival, which sounds like fun, and to spending some time in London. A week or so later, I’ll be in Oxford, attending the Clay Research Conference as well as a Physics from the Point of View of Geometry workshop in honor of Graeme Segal’s 80th birthday.
  • I’ve been spending the summer trying to write up some details of the ideas I’ve been working on, specifically the claim that the geometry of spinors in four dimensions allows one to think of one of the SU(2)s in the Euclidean Spin(4) symmetry as an internal symmetry. Still learning more about how this works, hope to have something ready to publicize within the next month or so.
  • For rest and relaxation I’ve been learning a bit more about various Langlands-related topics. The talks from the IHES summer school are mostly well-worth watching. Also very highly recommended are David Ben-Zvi’s lectures on The Langlands Program as Electric-Magnetic Duality given a couple weeks ago at a workshop in Cambridge.
  • Still trying to finish reading Récoltes et Semailles and decide whether to write something here about this bizarre and fascinating document. If you want to read this yourself, Mateo Carmona has a freely available transcription here.
  • There an interesting conversation about Ricci flow between my Columbia colleagues John Morgan and Richard Hamilton available here.
  • Sometimes it takes great self-control to avoid responding to things I see on Twitter. In the case of a recent exchange between Noah Smith and various people defending string theory. I couldn’t help myself and started writing something, then soon hit the character limit. This returned me to sanity as I realized that trying to have an intelligible discussion in the twitter format about anything complicated is just absurd.

    The gist of a lot of the discussion was that even string theory defenders now admit it was an overhyped failure as a “theory of everything”, but they then come up with new, improved hype. One argument seems to be that string theory has led to new developments in hype about black holes (for these, Scientific American has you covered here).

  • Today on Twitter Sabine Hossenfelder explains her current academic employment situation (no permanent position, latest grant application denied.) She’s a very unusual case, and has a successful new book and other ventures that to some degree can replace a standard academic income. For everyone though, the way academic jobs in theoretical physics work, if you decide you want to pursue topics other than very conventional ones that a group is already working on, you’re going to have a very hard time. Getting older and having a life also tends to be inconsistent with pursuing the very few opportunities that might come up.
Posted in Uncategorized | 7 Comments

Symmetry and Physics

Someone is wrong on the internet

It’s getting late, but I can’t help myself. Reading too many wrong things about symmetry and physics on Twitter has forced me to do this. And, John Baez says I don’t explain things. So, here’s what the relationship between symmetry and physics really is.

In the language of mathematicians, talking about “symmetries” means you are talking about groups (often Lie groups, or their infinitesimal versions, Lie algebras) and representations. The relation to physics is:

Classical mechanics (Hamiltonian form)

In classical mechanics the state of a system with $n$ degrees of freedom is given by a point in phase space $P=\mathbf R^{2n}$ with $n$ position coordinates $q_j$ and $n$ momentum coordinates $p_j$. Functions on this space are a Lie algebra, with Lie bracket the Poisson bracket
$\{f,g\}$. Dynamics is given by choosing a distinguished function, the Hamiltonian $h$. Then the value of any function on $P$ evolves in time according to
$$\frac {df}{dt}=\{f,h\}$$
The Hamiltonian $h$ generates the action of time translations. Applying the same formula, other functions generate the action of other groups (spatial translations, rotations, etc.). If your function satisfies $\{f,h\}=0$, it generates a “symmetry”, and doesn’t change with time (is a conserved quantity).

Quantum mechanics

Quantization of a classical system is something mathematically obvious: go from the above Lie algebra to a unitary representation of the Lie algebra. This takes elements of the Lie algebra (functions on $P$) to skew-adjoint operators on a Hilbert space, the space of quantum states. There’s a theorem (Stone-von Neumann) that says that (modulo technicalities) there’s only one way to do this, and it gives an irreducible unitary representation that works for polynomials up to degree two. For higher degree polynomials there will always be “operator ordering ambiguities”. The representation is given by
$$1\rightarrow -i\mathbf 1,\ \ q_j\rightarrow -iQ_j,\ \ p_j\rightarrow -iP_j$$
This is a representation because
$$\{q_j,p_k\}=\delta_{jk}\rightarrow [-iQ_j,-iP_k]=-i\delta_{jk}\mathbf 1$$
The right-hand side is the Heisenberg commutation relations for $\hbar=1$.

For more details, I wrote a whole book about this.

Posted in Quantum Mechanics | 32 Comments

Glashow Interview

David Zierler, the oral historian at the American Institute of Physics, has done many in-depth interviews with theoretical physicists in recent years. Today I came across a 2020 interview with Shelly Glashow, which was very interesting in general, and also answered a question I had always wondered about. Glashow was my undergraduate advisor at Harvard, where I was a student from 1975-79. From what I remember, his office was more or less next door to Steven Weinberg’s. It was well-known that they had been close friends, in the same class first at Bronx High School of Science, and then at Cornell. Towards the end of my time at Harvard I heard that their friendship was over and they were barely on speaking terms, but I never knew what had happened. In the fall of 1979, they were (together with Abdus Salam), awarded the Nobel Prize for their work on the unified electroweak theory.

In the interview, Glashow explains the story from his point of view:

Glashow:
by the late 1970s I began to think of myself as a Nobel contender. But I was under the impression that my old friend Steven Weinberg was doing everything in his power to keep the prize for himself and Salam. In particular—at a conference that he attended in Tokyo—he went out of his way to avoid mentioning my name at all while presenting the history of weak interaction theory. I got very upset by that omission. It was the issue which terminated our friendship. In the summer of 1979, I was invited to a meeting in Stockholm, to discuss the current state of physics ideas and others. Prior to the meeting, I sent a transcript of my talk to Steve. He was violently against my giving the talk. Because it examined various alternatives to what was then known as Weinberg/Salam theory. In fact, it was an open-minded talk in which I was discussing whether their—or more properly—our theory was a correct one or not. But it was such a heated discussion that I eventually had to simply hang up on him, because I had no intention of revising my talk. And I did not.

Zierler:
Was his assessment of your paper accurate in your mind?

Glashow:
I did talk about alternatives to the Weinberg-Salam theory. Yes. I was not yet convinced that it had to be true.

Zierler:
And what was your sense of why this was so unacceptable to him?

Glashow:
He thought it would endanger the Nobel Prize that he had campaigned for and anticipated for Salam and himself.

A copy of Weinberg’s Tokyo paper is here.

In the interview Glashow is scornful about Salam’s work and the campaign to get him a part of the Nobel Prize:

Glashow:
… Recall that Salam made a great deal of noise about why the prize should be given to he, Salam. I’ve been told that there were dozens and dozens of nominations of Salam. In fact, there’s a whole paper written about his shenanigans, which I can refer to you; written by Norman Dombey. Everything he says is true, to my knowledge….

My Nobel Prize depended on that one paper written in 1960. Steve’s Nobel Prize depended exclusively on that one paper he wrote in 1967, a wonderful paper which applied the notion of spontaneous symmetry breaking to the—my electroweak model. So, the question arises, what did Salam do? He introduced the electroweak—the SU(2)XU(1) model in 1964. That was over three years after I did. He copied my work but did not cite me…

Zierler:
Do you want to comment on why then he would have been a co-recipient of the Nobel Prize with you for this copy of your work?

Glashow:
I’ll explain it in a moment. But let me come back to—he also claims to the first to introduce spontaneous symmetry breaking in the paper that he wrote in 1968, one year after Steve wrote his paper. But that paper even cites Steve’s paper, so it is hardly the first time. He did what each of us had previously done, but much later. So why did he get a Nobel Prize? Very simply, he was nominated many times. Because he was Director of the International Center for Theoretical Physics in Trieste, Italy and he was very close with the directors of physics institutes in many countries; almost 100 of different institutions. And many of them wrote letters, by his instruction, using his words in some cases, encouraging the Nobel Committee to give the prize to him and also Steven. All of this documented, in fact, by the paper by Norman Dombey, who had access to Salam’s files in Italy, and has copies of the letters that he sent to other people encouraging them to nominate him. So, I think he shared the prize because he made a point of doing just that.

I wrote something on the blog about Donbey’s claims here.

Zierler also asks Glashow some questions about string theory, a topic on which Glashow’s views have been consistent from the beginning:

Zierler:
In retrospect, Shelly—how well do you think—has both string theory and your criticism of it aged over the past 30 years?

Glashow:
Well, it’s hard to answer that. String theory has become an established part of physics departments throughout the world, more so in Europe than in America. We still have some universities which are proudly string-free, like Boston University. We also have an awful lot of string theorists around who are twiddling their thumbs. It is not clear that string theory is going anywhere. I expect that string theorists would disagree with that assessment. But they are actually considering many other circumstances such as black holes in other spaces than ours, and there are all kinds of interesting things being done in mathematics, in physics, elsewhere by string theorists but with no relationship to the questions that interest me. They cannot answer the questions they set out to answer. That much is clear.

Zierler:
That’s as clear to you—

Glashow:
That was clear from the beginning, I think…

Glashow:
… I no longer feel so strongly about string theory. Why beat a dead horse? String Theory does not answer the questions that I’m interested in. I’m sad about that. I hope that they’re wrong. I have no reason to think that their horse is, in fact, dead, but it’s dead from the point of view of being useful to my way of thinking about physics. And I think that many experimenters feel exactly the same way, because string theorists say nothing about experiments that have or could be done. They only speak of experiments that cannot be done, which is somehow not interesting.

Update: Robert Delbourgo wrote in to point to his description of what happened in 1967. Here’s the relevant part:

I have been asked by the organizers to comment upon the the birth of the standard model during 1967 and Salam’s prominent role in it. This is an excellent occasion to set the record straight and recount my view of its history; if nothing else to refute innuendos which have occasionally surfaced during the 1970s that Salam was not deserving of the Nobel Prize. That autumn of 1967 I had been in charge of organizing the seminars at IC. Because Salam was constantly on the move and hardly spent more than one month at a stretch in London, I arranged with him to give a couple of lectures on his recent research (in October, to the best of my recollection) during his spell at IC to kick off the seminar season, as it was early in the academic year. He agreed to do so even though the audience attending those talks was somewhat thin. Paul Matthews was certainly present, but Tom Kibble was away in sabbatical in the USA. My memory of his lectures is a bit indistinct nowadays, but I do remember that he kept on invoking these k-meson tadpoles which disappeared into the vacuum which induced the spontaneous breaking of the gauge symmetry: what we now know as the expectation value of the Higgs boson. The resulting model looked rather ugly – and it still is – and I admit that I paid little attention to it; nor do I think that Salam himself was especially enraptured by the model’s beauty. A week or so later, I wandered into the Physics Library and came across Steven Weinberg’s Physical Review Letter, which I noticed looked suspiciously like Salam’s attempt. I showed the article to Salam, who was rather troubled that it was almost the same as his own research, but which was of course entirely independent. Matthews and I urged him to publish his work at the earliest opportunity and this happened to be the upcoming Nobel Symposium. As they say, “the rest is history”. I hope that this account of the events at the time scotches all aspersions that Salam should not have been a prize recipient.

Posted in Uncategorized | 28 Comments

Before the Big Bang: The Origin of the Universe from the Multiverse

There’s a new book out this month, Before the Big Bang: The Origin of the Universe from the Multiverse, about which we’re told:

One of the world’s most celebrated cosmologists presents her breakthrough explanation of our origins in the multiverse.

In recent years, Laura Mersini-Houghton’s ground-breaking theory, spectacularly vindicated with observational evidence, has turned the multiverse from philosophical speculation to one of the most compelling and credible explanations of our universe’s origins.

I spent a few minutes today looking through the book in the bookstore, trying to figure out where to find the details of the “spectacularly vindicated with observational evidence.” I didn’t see any references in the book, just a claim that in 2018 the author collaborated with Eleonora Di Valentino on showing vindication by observation. Presumably this is a reference to these three papers, but who knows. I don’t see anything like that in a quick look at the papers.

For many years I’ve spent a significant amount of time reading books and papers purporting to offer scientific evidence for a multiverse, trying to carefully understand the author’s arguments and write about them here (one example involved earlier claims by this author, see here). Few physicists though seem to care that bogus claims and pseudo-science about the multiverse have overrun their field and become its public face. I’ve come to the conclusion that best to not waste more time on this.

Update: Will Kinney reminds me that he wrote a paper about this, see here, as well as here and here for more about the story of that paper. Also see another old posting, here.

Posted in Book Reviews, Multiverse Mania | 17 Comments

Strings Black Holes 2022

Each summer for nearly a quarter-century there has been a big yearly conference bringing together the string theory community. I’ve often written about these conferences on the blog, see here. This year’s version will be held next week in Vienna, for more information see here.

Taking a look at the program, one thing that stands out is that the string theory community has almost completely stopped doing string theory. Looking at the program, only two out of 44 talks seem to be significantly about string theory. One of three parallel discussion sessions is entitled “Strings and the Real World” and will be chaired by Cumrun Vafa. I’m guessing this will mostly be about the swampland, not string theory.

A tradition at these conferences is one or more public talks designed to publicize string theory. This year’s versions will be given by Netta Engelhardt and Andy Strominger. They have nothing to do with string theory, but they do make very clear what the string theory community has found to replace string theory: black holes. Engelhardt’s title is “The Black Hole Information Paradox: A resolution on the horizon?” and Strominger’s is “Black Holes: the Most Paradoxical Objects in the Universe”.

Looking at the talk titles, the most common words in the titles are “holography” and “black holes”, with the center of gravity of the subject now for a couple decades the effort to use holography to say something about black holes. Maldacena’s title is “What happens when you look at supersymmetric black holes for a long time?” which seems also an interesting question about the field itself.

Update: Paolo Bertozzini points out to me that the LQG community has scheduled its big yearly conference LOOPS2022 at exactly the same time as the string theory community one (this week). It’s quite interesting to compare and contrast the two sets of talks. There are some very broad similarities between what both communities are doing, with overlaps in interest around black holes, entanglement, holography (in the form of large symmetry groups at infinity). Another commonality is that both communities are focused on the gravitational field, with nothing to say about particle physics and matter in general. This has been true of LQG since the beginning. In the case of string theory the big selling point originally was that it gave a theory of matter, but the string community has for a long time given up on that. There is a difference in how the communities think about “what are the fundamental degrees of freedom for gravity?” On the string theory side they’ve given up on that, the answer now is that gauge-gravity duality and emergence are supposed to allow you not to care about fundamental degrees of freedom. On the LQG side, people are still hard at work on specific sorts of degrees of freedom and how to quantize them.

Posted in Strings 2XXX | 31 Comments