- Paul Frampton has been found guilty on drug charges in Buenos Aires, looks like he will be able to serve out his sentence under house arrest, get released sometime in 2014. It’s unclear at this point how the University of North Carolina will handle this. For details, there’s Physics World, the Daily Mail, the Winston-Salem Journal, and Clarin.
- Erik Verlinde over the past couple years has gotten 6.5 million euros in prizes and grants to fund his work on entropic gravity (see here). Now, he’ll head up a new institution, the Delta Institute for Theoretical Physics, funded with 18.3 million euros from the Dutch scientific funding agency NWO as part of its Gravitation Programme.
There’s an interview with Verlinde here. He says he’s working on explaining dark matter with his entropic gravity ideas. There’s no paper about this, I guess because:
There are some small gaps in my reasoning and things that I still do based on intuition. I’m trying to fill in those gaps.
but he thinks these ideas about dark matter will be tested in “no more than 10 or 15 years”.
- Another new theoretical physics institution is The Higgs Centre for Theoretical Physics in Edinburgh, where they’re hosting an inaugural symposium in January.
- The latest TEDYouth is online, see here. It seems that they may think that Youth these days is pretty ADD, since they have all presentations limited to six minutes. In one of them (around 3:50) they’ve got Clifford Johnson explaining the exciting new idea of replacing particles by strings moving in extra dimensions.
- Mochizuki’s claimed proof of the ABC Conjecture still seems to be resisting the attempts of experts to understand and evaluate it. He has put on his web-site some slides for a talk next month, and promises a survey article next March.
- Easier to follow in principle, but at 367 pages still pretty daunting, is a new paper from Laurent Lafforgue, chronicling his attempt to develop “non-linear” versions of the Poisson formula that would imply Langlands functoriality.
- If you were wondering about that tatoo in Edward Frenkel’s film, see Mathematics, Love and Tattoos for an explanation.
- In other film news, there’s the Colliding Particles project for a film about the Higgs. They’ve got a new segment up, several more coming soon at one/week.
- The debate in the HEP community about the death of SUSY goes on, and will undoubtedly continue along the same lines for quite a while. Latest is from New Scientist, which has Steven Weinberg describing the situation in a way that that can’t be argued with:
SUSY’s plausibility is reduced, but not to zero.
For the argument over whether SUSY was and is an overhyped, implausible idea, on one side there’s Michael Peskin, with:
I think that the serious effort given to SUSY is appropriate…”
and on the other, taking the Not Even Wrong side of this argument, there’s Matt Strassler with:
The theory, specifically as something we would observe at the LHC, was wildly over-promoted.
Update: One more. A Science magazine article about the problem with “Open Access” journals discussed here. According to Science:
Meanwhile, the OA industry is becoming increasingly diverse; it includes traditional powerhouses, such as Germany’s Springer, which now publishes about 300 OA titles, as well as a vast array of newcomers. OA publishers have a built-in incentive to lower the bar, Dupuis says, because in contrast to subscription journals, an OA title earns more revenue with every paper its editors accept.
Moreover, many so-called predatory publishers—which often eschew peer review, use fake editors, or contain plagiarized papers—have flooded the market, says Jeffrey Beall, a librarian at the University of Colorado, Denver, who keeps an online list of these dodgy outfits.
Wow, I didn’t know that about Verlinde receiving many millions for his ideas about explaining dark matter with entropic gravity. I thought his ideas about gravity being entropic had been debunked a while ago. But it is particularly ridiculous to richly finance his claim that dark matter can be replaced by modified gravity.
Verlinde has given talks on this, and it appears to be just the old Milgrom idea of declaring Newton/Einstein gravity wrong on galactic scales, and replacing F=ma, by some other law, when ‘a’ drops below a critical value. This forces individual galaxies to get roughly the right rotation curve. The new twist on Milgrom’s idea is that Verlinde attaches this to entropy in some weird way.
While this was an interesting idea by Milgrom back in 1981, I don’t think it is interesting anymore; the jury is in: such a model *does not work*. It is incompatible with a host of observations, including large scale structure formation, CMB data, weak lensing, lyman alpha forrest, bullet cluster, etc. I don’t think there are many decent cosmologists who take the modified gravity models seriously anymore. Instead, dark matter is unavoidable and explains many of these different observations beautifully. So it is shocking that the Dutch are unaware of this and are just pumping millions into this 30 year old dead idea.
Yes Bob, but the fact that the LHC has failed to show even a tiny possibility of a dark matter Lightest Supersymmetric Particle kinda helps promote alternative explanations of dark matter.
I hope you aren’t arguing that Verlinde’s ideas must not be pursued simply because experimental evidence is against it – I mean, imagine what that would that do for SUSY and String Theory research funding
@jg, your comment was one of the more bizarre I have seen. 2 comments:
1) I didn’t mention anything to do with SUSY whatsoever. Unlike you, I am not advocating SUSY.
2) Absence of evidence is not evidence of absence — the dark matter particle can just be very weakly interacting and this is compatible with all the data. But my main point was that for Milgrom models of modified gravity, the jury is in; it is ruled out by the data.
I was just responding to you very forceful arguments that Verlinde’s ideas are dead and the possibility that anyone might fund his research is irresponsible.
Anyway, a few other comments on threads mentioned:
ABC Conjecture: give it up already, either prove it elegantly or go do your obscure maths ideas in another area.
Edinburgh: You could have done this a few years ago really.
jg: “ABC Conjecture: give it up already, either prove it elegantly or go do your obscure maths ideas in another area.”
Come here and tell me that… You can’t last two minutes in my world.
I lived through Wiles proof of FLT, really, I was at the universities involved over the Summer and Autumn (and subseqent Spring), I was as excited and thrilled as anyone could be, and lived through the doubts and final vindication.
This ABC “proof” doesn’t taste anything like it, Wiles’ proof was backed up by a huge amount of accepted theory, and was in fact (eventually) a fantastic validation of much of 20th century PURE mathematics.
Verlinde got a video out in bigthink:
The video has 200K+ views. It is sad to see how speculative nonsense is presented to common mass as a legitamate science and that too by prominent scientists.
Regarding Langlands and L.Lafforgue, there’s also been a recent preprint by V.Lafforgue, a younger brother of the former, which apparently proves a generalisation of his big brother’s famous 2002 results with new different ideas, see http://arxiv.org/abs/1209.5352 (all this is way over my head, just noticing).
Bob, your arguments are simply ridiculous. Nobody working on MOND these days claims that this formula explains everything. What it does not explain, it does not explain. And it is *not* a theory at this stage. But the formula, simple as it is, explains a *lot* of things and does this in an impressive manner, which plain simple collisonless CDM cannot do at the moment, and will probably never do. It is an incredibly weak argument to pretend that “MOND just makes rotation curves flat”, “was designed to fit galaxies” or stupidities of that kind… These arguments only reveal a very embarassing lack of reflection of its authors on the topic, and a refusal to read or try to understand all the serious papers referring to it. For instance, there has been a recent review in LRR showing what MOND does, and why it is still taken seriously (yes, seriously enough to have an invited LRR review about it): http://relativity.livingreviews.org/Articles/lrr-2012-10/ This article is not putting the problems of MOND under the carpet. To make a long story short, MOND proponents fully agree that some sort of dark matter does exist, but what they think is that it is *not* made of CDM particles. The reason for this is that MOND is right *as an empirical scaling relation* in galaxies, whatever dark matter’s deep nature is. Even the most fanatic (but educated) CDM afficionados cannot disagree with this. But cosmologists seem to deliberately ignore this fact, because, to quote them, “they do not care about the details of messy astronomical systems such as galaxies”… And this might be a big mistake, because what the success of MOND might tell us about the nature of dark matter might really be fundamental… And how much you think the latter sentence is true depends on how far away from the galactic scale your main research interests lie. What strikes me is that when people say “MOND is wrong” or “MOND is right”, they dont necessarily mean the same thing, because some think it is a synonym for TeVeS, and those people are mostly *NOT* working on galaxies (and obviously they are mostly finding problems with the whole modified gravity approach), while some others (mostly working on galaxies) just think it is the most awesome scaling relation to date, summarizing almost all scaling relations of both spiral and elliptical galaxies, let alone dwarf spheroidals, but including tidal dwarf galaxies that are much less well understood in the CDM context. While they all agree on the problems to explain the CMB and clusters of galaxies, they simultaneously think “MOND works too well in galaxies to be meaningless”. Again, this absolutely doesnt mean “dark matter doesnt exist”. There is a big difference between believing in dark matter, and believing in the current LambdaCDM model. As a conclusion, the success of MOND as an empirical relation in galaxies is just a huge fine-tuning problem that we need to understand, as there are many in physics. The problem right now is a majority of astronomers and cosmologists *completely* (and often deliberately) ignoring this fine-tuning problem. In this sense, Verlinde is a light in the dark!
Teleos, your comments are irrelevant. You say “MOND proponents fully agree that some sort of dark matter does exist”. Fine. But Verlinde does not. Verlinde believes in the old Milgrom story of no dark matter at all. And, as I pointed out, this contradicts CMB data, large scale structure formation, weak lensing, bullet cluster, lyman alpha forrest, etc. So that is definitely a dead idea. Please try to read and comprehend before responding in the future.
Bob, Verlinde is *not* saying this, and MOND proponents do not either. MOND *is* a success as an empirical formula in galaxies and one has to understand this, one way or another, fullstop. Please read the relevant serious litterature if you wish to debate further.
It might well be that we will understand why galaxies behave in this way within the CDM context, but one still has to demontrate how, and pretending that we right now do understand this would be of the utmost intellectual dishonesty. An interesting review, very optimistic for CDM but also quite honest about the current lack of understanding of large number of phenomena on galaxy scales is for instance given in: http://arxiv.org/abs/1207.3080 Knowing that Silk and Mamon have long been defending CDM, the simple fact of saying “Whether appeal to alternative gravity is justiﬁed by inadequate baryonic physics is a question of judgement at this point” reveals that they are not as sure of themlselves as uneducated people like Bob.
Teleos, I attended a talk where Verlinde said that in his model there is no dark matter.
Please, enough about MOND. If someone has a well-informed comment about Verlinde’s ideas that’s great, but this kind of argument over MOND is both off-topic and unenlightening.
Useful: discussing gravity with Verlinde
To end-up this discussion, I hope it is not too much off-topic to say that Verlinde’s approach to the DM problem should very likely be in the spirit of http://arxiv.org/abs/1005.3537
Concerning SUSY, I’ve read in the book by Cottingham and Greenwood (“An Introduction to the Standard Model of Particle Physics”) that SUSY requires energies near 14 TeV to be observable (page 18). But so far the LHC has reached 7 to 8 TeV. So why the discouragement? Is it that some of the superpartner particles were expected to show up at current LHC energies? (I guess this might depend on which version of SUSY one is talking about.)
You’re misreading the book you quote, which says
“It is also widely believed that the physics of Supersymmetry, which perhaps underlies the Standard Model, will become apparent at the energies, up to 14 TeV, which will be available at the LHC”
Note the “up to”. The arguments for LHC-scale SUSY (either things like the MasterCode fits, or the idea that SUSY would solve the hierarchy problem and avoid fine-tuning), all predicted that seeing SUSY would not require the full 14 TeV, but be visible at 7-8 TeV (a factor of 3.5-4 above the Tevatron energy). Whatever they’re saying now, I don’t think one can find any SUSY enthusiast who a couple years ago, just before the 7 TeV turn-on was saying “too bad, that’s not enough, it’s not until 14 TeV that it will show up”.
Yes, when they say that SUSY will become apparent at energies “up to 14 TeV,” I’d hardly think that they’re saying they would be expected to appear at 7 or 8 (or lower). It means one should allow up to 14 TeV energies before can exclude the idea. It is true, though, that it’s not looking too good (but at one point the discovery of the “Higgs boson” didn’t look good either). One thing that does seem more clear is that some models that require some masses for superparticles have been excluded by the LHC.
The only reason the 14 TeV number is in that sentence is because it is the design energy of the LHC, not because it has anything to do with SUSY. You’re trying to put words in the mouths of those authors which they did not intend. When they were writing, no one knew about the magnet interconnect problems and everyone assumed the LHC would quickly run at or near design energy.
Yes, as a matter of logic, until one runs the LHC at design energy one won’t be able to exclude the possibility of the LHC discovering SUSY. This doesn’t change the fact that pre-LHC the predictions for SUSY were for it to be visible at 8 TeV, not for it to require 14 TeV.
The Science magazine article reminded me about this joke
Gold open access: enter the mouth
Maybe someone can clarify the following to me. I heard a talk by E Verlinde in which he explained DM using the off-diagonal components of the matrices in matrix models of strings. There was no mention of entropic gravity, or gravity as an emergent phenomenon in any form. He seemed to be using those degrees of freedom in matrix models that are usually discarded. But since these are models of strings, the graviton is non-emergent.
Am I right? or do I miss the point?
There is nothing ridiculous in what Verlinde is trying to do – in fact, if you look at the “entropic” derivation of the Einstein equations, it is the most natural thing.
The only strange aspect is that this is not Verlindes idea. The idea is from Ted Jacobson and goes back to 1995.
Please note that the 18 million euro’s is not quite ‘Verlinde’s’ money: it’s a 10 year grant to cover quite a big field in a collaboration which involves 6 profs – one of whom is ‘t Hooft. Yes he’s involved. No, it’s not his personal pot of gold.
@chris I may be wrong, but I think that T Padmanabhan’s work on the subject is earlier than T Jacobson’s. I also find his papers clear and well thought-through.
Aha … http://en.wikipedia.org/wiki/Thanu_Padmanabhan
Well, I certainly hope for the success of this program. And if not, I’m sure there will be things learned.
In the Scientific American article linked from the Wikipedia entry, Padmanabhan has this to say about the history of the “gravity as an emergent phenomenon” idea:
“This idea that gravity is an emergent phenomenon has a long history. It was first introduced by the Russian scientist, Sakharov, in 1968. Another intriguing connection, suggesting similarity between the surface properties of black holes and fluid mechanics was investigated by T. Damour, Kip Thorne, W. Price and their collaborators in the eighties. An attempt to obtain Einstein’s equations from a thermodynamic perspective was made by T. Jacobson in 1995. Other approaches, very similar in spirit, were developed by G. Volovik and Bei-Lok Hu. My collaborators and I [Thanu Padmanabhan] started on a concrete programme to explore this idea in 2002. More recently, E. Verlinde has tried to reassemble many of these ideas from the perspective of string theory.”
New form of matter at LHC?
According to the report linked above, the new form of matter from LHC was submitted to “Physical Review B”. This is interesting ! But when I clicked the arXiv link, the paper was sent to Physics Letters B. In fact, I think PRB might actually be a suitable place for this work. Maybe at this level, there is already some new emergent physics which is independent of the underlying constituent particles. And it would be cool that LHC publishes something on PRB.
Since you mention big private grants for theorists, you might want to also mention that
whole accellerators are
facing the axe due to “austerity”.
Both RHIC and B-physics were in the past thought to be likely places where string theory/SUSY were to “confront experiment”, but it now looks like these experiments wont even take place.
Thanks. I’ve been having trouble following the US budgetary issues, since it seems unclear what the budget situation will be in a month or so, much less in the longer term.
About the Italian decision canceling SuperB, besides the Physics World article, there’s also some discussion of this at Tommaso Dorigo’s blog, see
Chris, the most natural thing is that dark matter is a boring old stable neutral particle. The least natural thing is that it is an artifact of entropy and string theory as Verlinde claims it is.
I was wondering why Verlinde’s work creates these more emotional responses from the physics community. Would it be possible to point out a good paper with a line of argument why his hypothesis is now referred tot as “dead” or “debunked”? If it is proven wrong, are there still lessens learned? I am just interested in the idea and wonder how much effort I should spend following Verlinde’s thesis. There seem to be a mismatch between the excitement in public media and the more critical statements from the scientific community.
Stefan, Please see these links for interesting reactions:
The neutron argument seems to go right to the heart of whether or not we really understand any entropic force: i.e. can they be reversible, do they have to de-cohere a wave function?
JR, thank you so much! This helps me a lot! thanks 🙂