Various and Sundry

  • It seems to be too early for April Fool’s day, and yet the arXiv has Dark Matter as a Trigger for Periodic Comet Impacts by Lisa Randall and Matt Reece, a preprint described as “Accepted by Physical Review Letters, 4 figures, no dinosaurs.” The Register has a story: Dark matter killed the dinosaurs, boffins suggest.

    Also recently at the arXiv in a similar “too early for April 1” category is Crossing Stocks and the Positive Grassmannian I: The Geometry behind Stock Market, which deals with the “stockmarkethedron”, also known as the Geometrical Jewel at the Heart of Finance.

  • The president’s FY2015 budget request is out, with news for HEP not so good: a 6.6% cut proposed in DOE HEP funding. No details about the NSF budget, but the proposal is basically for flat funding (an overall cut of .03% in the research budget). The NSF is proposing one big increase, 13.5% for management. This is just an initial proposal from the administration, with the possibility of something different ultimately emerging from Congress.
  • The particle physics documentary Particle Fever opens here in New York at Film Forum tonight, with appearances tonight and this weekend by the director and “physicists from the film”. There’s a review in today’s New York Times.

    I saw the film last fall at the New York Film festival and wrote about it here, with the summary:

    most of it I thought was fantastically good and I really hope it finds distribution and gets widely seen. On the other hand, some of it I thought was a really bad idea.

    The film is a very inspiring inside look at the LHC experimental search for and discovery of the Higgs. My misgivings were about the theoretical framing of the story, which was the Arkani-Hamed point of view that this is all about two alternatives: SUSY or the multiverse. The NYT review shows that these misgivings were quite justified, with the reviewer’s summary of what they learned about the significance of the Higgs from the film:

    While the discovery of the Higgs may not have immediate consequences for the way we live, or applications in the world of technology and industry, its implications, according to “Particle Fever,” could hardly be more profound. Through most of the film, the scientists are awaiting a specific bit of data, a single number that will either vindicate a theory of the universe known as supersymmetry or suggest the possibility of multiple universes.

    The differences between these two outcomes seem very stark. In the first case, more particles are likely to be found, contributing to a detailed and orderly picture of the nature of things. In the second, the Standard Model will be thrown into chaos, and the stability of the universe itself may be called into question. It won’t be the end of the world, but for some theorists, it will feel that way.

    Mr. Kaplan is hoping for supersymmetry. His friend and sometime table tennis partner, Nima Arkani-Hamed of the Institute for Advanced Study in Princeton, is in the multiverse camp.

    Physicists often get outraged when they feel journalists badly misrepresent science to the public. Will they get equally outraged when it is physicists doing the misrepresenting?

  • For some insight into the current concerns of particle theorists, you can watch some of the videos at last week’s KITP conference. In particular, there’s Matt Strassler’s talk, where he got all Peter Woit and argued that “one could make the argument” that not seeing SUSY (or anything else stringy) at the LHC “would be significant circumstantial evidence against string theory as a description of nature” and that just seeing the SM at the LHC would be “circumstantial evidence against effective quantum field theory as a complete description of known particle physics”. This got him an argument from Gross about his insufficient enthusiasm for a 100 TeV collider. Gross then also got all Peter Woit, arguing that the failure of the “naturalness” argument for new physics was no big deal since it wasn’t a very good argument to begin with (I get all sorts of grief when I do this..).
    The conference ended with a session of people trying to predict the future of the field 30 years hence. This was mostly pretty discouraging, with a lot of people envisioning more of the same: endless generalities about quantum gravity, firewalls etc. Prominent by its absence was any role of mathematics in theoretical physics, with only Greg Moore speaking up for the question of the significance of now popular 6d superconformal theories, and Nati Seiberg mentioning that connections of the field to mathematics were a good thing.

    Lots of talks mentioned people’s good experiences working with and interacting with Polchinski, who seems to be a very nice guy. I’ve never met him personally, but people have speculated to me that he had something to do with the decision of the arXiv to block links to my blog (he was unhappy about my characterization of his Scientific American article promoting the multiverse). What the truth is about that particular story I suppose I’ll never know.

: Another review of Particle Fever leads with this explanation of the main point they got from the film:

Stakes come no higher than in Particle Fever, a dazzling, dizzying documentary about nothing less than whether we exist in a coherent universe of ordered, even beautiful laws — or whether, as Princeton physicist Nima Arkani-Hamed theorizes, our universe is one of an infinite set of other universes defined by a chaotic mash-up of unstable, inexplicable, random conditions.

Update: Reddit has a live Q and A with physicists involved in the film. Savas Dimopoulos (described as “considered the most likely to have a theory confirmed by the LHC”) argues for the multiverse and tells questioners that “We may know about whether Nature prefers the Multiverse or the more traditional (super)symmetry path after the second run of the LHC which will start in a year.” Arkani-Hamed also gives the multiverse argument, also claiming “I envy anyone who is jumping into fundamental physics as a grad student today!”. No theorists in sight who might think there’s more significance to the negative LHC results about SUSY than “must be the multiverse”.

Update: Reddit the next day hosted a live Q and A with Michio Kaku. He there explains to the public that:

The best theory comes from string theory, which states that dark matter is nothing but a higher vibration of the string. We are, in some sense, the lowest octave of a vibrating string. The next octave is dark matter….

The next big accelerator might be the ILC in Japan, a linear collider which might be able to probe the boundaries of string theory…

In the coming decades, I hope we find evidence of dark matter in the lab and in outer space. This would go a long way to proving the correctness of string theory, which is what I do for a living. That is my day job. So string theory is a potentially experimentally verifiable theory.

Seems that well-known theorists going on Reddit to mislead the public is now a daily phenomenon…

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25 Responses to Various and Sundry

  1. imho says:

    First, what’s wrong with the Randall Reece paper. Why is it absurd that dark matter can influence Fermionic matter. I haven’t read the paper, but I’m sure they at least did some back of the envelope calculations to test plausibility. These aren’t Brane Worlds – a fairy tale wrapped in a fairy tale – this is solid falsifiable Physics. So why the negativity?

    Second, how is talk about Firewalls discouraging. This whole business of connecting entanglement to gravity seems new and exciting, and imho, smells like the beginnings of something profound. I’d put my money, and perhaps direct a little bit of funding, towards The Thermodynamics of Entanglement… it has such a nice ring 🙂

    Finally, there is nothing wrong with rebalancing national research priorities. Sometimes a tweak here or there is healthy.

  2. Peter Woit says:

    Of course dark matter can influence other matter. And maybe what Randall-Reece are suggesting for a major solar-system effect of dark matter makes sense (I don’t know enough about solar-system astronomy to have any real idea). Still, seems to me that a “dark matter killed the dinos” PRL paper sounds like an exceptionally clever April 1 stunt.

    The black hole information paradox is now at least 30 years old, with debate about entanglement and gravity going back at least that far. I haven’t seen any really solid insights into quantum gravity coming out of this so far, and another 30 years of the same doesn’t seem like an inspiring vision to me. But others who feel differently should follow their inspiration. Given the latest trends, I’m not worried about the idea of “thermodynamics of entanglement” not getting enough attention (some days it seems hard to find a new hep-th paper on the arxiv that doesn’t have “entanglement” or “entropy” in title/abstract).

  3. Giotis says:

    The theory Greg Moore has in mind is the interacting 6d (2,0) SCFT.
    It is inherently Quantum mechanical with no classical limit and without a (known) langrangian. It is the field theory with the highest Super symmetry in the highest dimensions and a mother theory of 4d SYM and of other interesting field theories.

    It is dual to M theory on AdS7xS4 and describes the dynamics of multiple coincident M5 branes. It is also known as the theory of tensionless self dual strings since as the M5 branes approach each other the self dual strings in their world volume (coming from the M2 branes stretched between them) become tensionless.

    So indeed it is a remarkable theory but still mysterious. Understanding it better is crucial for M theory and QFT in general…

  4. Asnant says:

    Thought you might like this link 😉

  5. Peter Woit says:

    Sure, but Slashdot is kind of behind the times, since that’s pretty much from May of last year, see

  6. gs says:

    No details about the NSF budget, but the proposal is basically for flat funding (an overall cut of .03% in the research budget). The NSF is proposing one big increase, 13.5% for management.

    But of course! Management needs more resources to navigate the tight budget.

    (Back when I was in school HR, still called Personnel at the time, responded to a budget crunch by requesting additional staff to handle layoffs.)

  7. Neil says:

    I do find the firewall result interesting. Yes, the blackhole information paradox has been around a long time, but the firewall (possible) resolution is new. Since there appears little or no way to explore the issue experimentally, the fact that we have this logical inconsistency between QFT and GR on the event horizon offers some hope, I think, for making progress on the quantum gravity agenda (which has been stalled a long time).

  8. So says:

    Peter, can you argue a little about that jewel in finance ? Why is it absurd to use combinatorics in finance ? It looks fine to me, but I’m not an expert in stock market !

  9. Michael Hutchings says:

    So: the “crossing stocks” paper does not say anything useful about finance. It starts with the observation that if you plot several stock prices on the same graph then the curves sometimes cross either. It then uses this a launching point to start rambling about permutations and various related topics in combinatorics. I’m kind of amazed that this paper even made it onto the arxiv.

  10. So says:

    Michael : Do you know what a crossing of stocks means for the market? In other words can you tell how the crossing affects an investor portfolio?

  11. S. Molnar says:

    Almost, but not quite, amusing typo: “feel journalists badly”, not “feed journalists badly”.

  12. Dave Miller in Sacramento says:


    Polchinski and I were in the same dorm for three years as undergrads and then we overlapped for a year or two at SLAC when I was finishing my doctorate and he was a young post-doc. So, I knew Joe pretty well, though I can’t claim we were close buddies, since I was a very prudent fellow and Joe was one wild-and-crazy guy (I won’t relate all of his exploits except to say that it is good that he did not fall down the nine-story air-shaft when he was climbing up the air-shaft to the roof of the Caltech library!).

    I have no specific information about Joe and links to your blog at the ArXiv, but it does not sound like Joe at all: he was always a very free-wheeling, libertarian kind of guy. Of course, people change, but it would surprise me if he was involved in blocking links to your blog.


  13. Peter Woit says:

    S. Molnar,
    Thanks, fixed.

  14. Peter Woit says:

    Dave Miller,
    Thanks. One thing I learned during the “string wars” though was that when you publicly criticize people who are used to adulation rather than criticism, you get some very odd and unusual behavior from otherwise sensible and mild-mannered people. One strange thing is that from everything I’ve heard, what upset Polchinski here is public criticism of the multiverse, of a sort rather typical or even milder than typical opinions of his colleagues about this (they just weren’t making these publicly).

    I don’t know what the true arXiv story is, but from what Polchinski wrote publicly about this on blogs, and from what I’ve heard from others about his private comments, I wouldn’t describe any of it as a libertarian defense of the rights of others to express views he didn’t like.

  15. Low Math, Meekly Interacting says:

    Of course, New Scientist is all over the dinosaur thing.

    That said, however plausible, it’s plenty falsifiable. A theorist could do worse.

  16. Anony says:

    Peter wrote — No theorists in sight who might think there’s more significance to the negative LHC results about SUSY than “must be the multiverse”.

    Theorists would be the losers if they do not think of alternatives other than these two — the more likely thing is that there are theorists who think of alternatives but are not necessarily projecting their work, other than publishing it in journals. Popular media and even physics blog follow the more well known and outspoken ones and do not look at on going research work.

    For example there can be fine tuning in other gauge symmetry breaking scales — not just the standard model scale — and this does not bode well either with multiverse (no anthropic reason for it) or SUSY. For example any non-SUSY model with additional groups including GUTs, belongs in this category where more gauge groups potentially have the hierarchy problem….and there is lot of research with such groups.

    An interesting result is at (Click) which obtains bounds on the scale of B-L gauge symmetry breaking in left-right symmetric models using the hierarchy problem.

  17. Casey Leedom says:


    Arkani-Hamed … also claiming “I envy anyone who is jumping into fundamental physics as a grad student today!”

    He must really be bitter if he’s recommending HEP for current students. Don’t get me wrong, I’m an avid follower of physics news, etc. but it’s definitely not an easy field to be invested in these days.

  18. Sterling says:

    Hi Peter,

    I found it interesting that both Brian Greene and Michio Kaku did AMAs within 24 hours of each other on Reddit.

    While I am aware both have taken roles as “popularizers” now, something that bothered me was that Kaku described himself as a “leader in the field” and a “co-founder of string there”, while Greene, who is more cited so arguably more influential, did no self accreditation.

    Maybe I read too much into this, but I almost feel like the two are fighting each other for supremacy as “top” popularizer.

    (Here the Greene AMA in case you missed it:

  19. Peter Woit says:

    I did take a quick look at Brian’s Reddit AMA, and it seemed to me he was careful to avoid making unsupportable claims about the LHC/ILC and string theory, or engage in the kind of self-promotion Kaku favors. In Brian’s case, his focus is on his World ScienceU project, which has just launched:

    As far as I know though, neither Brian nor Kaku seem to have ever even considered making outrageous claims that the LHC provides evidence for the multiverse, along the lines of what Arkani-Hamed and Dimopoulos are engaged in and the film promotes. The Salon piece drl links to is pretty amazing, bashing creationists by holding up Dimopoulos and his multiverse claims as a sterling example of how different scientists are. If you want to torpedo the credibility of science, this is a good way to set about it.

  20. Neil says:

    OMG, what is an AMA?

  21. Peter Woit says:


    I learned this yesterday: AMA= “Ask Me Anything”

  22. Luigi Vampa says:

    Peter, do you think Kaku and others like him have committed acts of sufficient harm to the public and to science such that their tenure should be revoked?

  23. Peter Woit says:

    Tenure is designed to ensure people’s freedom to express their ideas, no matter how wrong-headed. There will always be physicists getting attention by making silly and misleading claims about fundamental physics, if you want attention, it’s a lot easier to do that than to get attention for something serious. To me the problem is the rest of the (tenured) physics community: one reason they have tenure is so that they can challenge nonsense put before the public by prominent colleagues. I very rarely see any of them doing it.

  24. srp says:

    Saw Particle Fever last night with the editor and David Kaplan present for some Q&A afterward. They had over 500 hours of footage to condense into a movie, so it occurred to me that to some extent their problem was analogous to the LHC experimentalists: How do we handle this surfeit of information, decide what to throw away, and develop a truthful and interesting story about the phenomena?

    In my opinion, I would have preferred more inside stuff from Atlas about deciding on what was noise v. signal, how blinding works, debates over how to set triggers, etc. To make room, I would have cut some of the redundant theorists’ agonizing over their lives’ work being at risk–some of that is fine, but they almost made that the main story.

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