Not Even Wrong

The big yearly SUSY conference, SUSY 2013 has been going on in Trieste this past week. From the experimentalists, the news is just stronger limits: no hint of SUSY anywhere in the LHC data. From the theorists, the reaction to this news has been pretty consistent: despite what people say, not a problem.

According to John Ellis, everything is fine, with MSSM SUSY preference for a Higgs below 130 GeV vindicated and successful SUSY predictions for the Higgs couplings (that they should be the same as if there were no SUSY). According to Ellis, we just need to be patient, and he has CMSSM fits preferring 2 TeV gluinos.

However, if you look at Savas Dimopoulos’s talk the MSSM gets a grade of D-. He argues that the LHC has shown us that the answer is the Multiverse, and that split SUSY with its fine-tuning gets a grade of A. The grade inflation in particle physics is pretty dramatic: you now can get an A without your theory having the slightest bit of experimental evidence.

Nima Arkani-Hamed’s talk was about SUSY in 2033, which in his vision will be pretty much the same as SUSY in 2010. Remember all those things the LHC was supposed to find but didn’t? Well, now the argument is that they’re really there, but we will need a 100 TeV collider to see them. If all goes well, in 2033 such a machine will be under construction, and SUSY 2033 could feature all the SUSY 2010 talks retreaded, with 1 TeV gluinos moved up to 10 TeV.

One of Arkani-Hamed’s slides makes me worry that the LHC results have caused him to begin to lose his marbles. He claims that if one doesn’t see new physics like SUSY at the 100 TeV machine, in his view

this would be 100 times more shocking and dramatic than no nothing but Higgs at the LHC

[I initially misread and misquoted this, my apologies. The claim was not that no BSM at 100 TeV would be 100 times more shocking than no Higgs at the LHC, but that it would be 100 times more shocking than no BSM at the LHC. So, the usual sort of over-the-top exaggeration, but not crazy.]

Even wilder claims came form Gordon Kane in his talk, where we’re told that particle theorists giving “negative” talks because of the LHC results have:

no knowledge of LHC physics, Higgs physics, supersymmetry, phenomenology, etc.

According to Kane, we not only have seen the tip of the iceberg of a unified string/M-theory, but actually have the whole iceberg. The ingredients are all in place for what he sees as a similar experience to the 3 year period in the 1970s when the Standard Model emerged and was experimentally vindicated.

Tommaso Dorigo points out that there was one SUSY 2013 talk that in his humble opinion was a good candidate for the IgNobel, see here (warning, NSFW).

On a more positive note, at the conference production of compactified Calabi-Yaus was finally conclusively demonstrated.

Update: Nathaniel Craig has some recent lectures on The State of Supersymmetry after Run I of the LHC. The emphasis is on examining the consequences of failure of pre-LHC assumptions about SUSY based on simplicity and naturalness. Out of 60 or so pages, only one is devoted to the models favored by Arkani-Hamed and Dimopoulos, string-theory based models are not even mentioned.

There are two workshops going on this week that you can follow on video, getting a good idea of the latest discussions going on at two different ends of the spectrum of particle theory in the US today.

At the KITP in Santa Barbara there’s Black Holes: Complementarity, Fuzz or Fire?. As far as I can tell, what’s being discussed is the black hole information paradox reborn. It all started with Joe Polchinski and others last year arguing that the consensus that AdS/CFT had solved this problem was wrong. See Polchinski’s talk for more of this argument from him.

If thinking about and discussing deep conceptual issues in physics without much in the way of mathematics is your cup of tea, this is for you (and so, I fear, not really for me). As a side benefit you get to argue about science-fiction scenarios of whether or not you’d get incinerated falling into a black hole, while throwing around the latest buzz-words: holography, entanglement, and quantum information. If you like trendy, and you don’t like either deep mathematics or the nuts and bolts of the experimental side of science, it doesn’t get much better than this. One place you can follow along the latest is John Preskill’s Twitter feed.

Over on the other coast, at the opposite intellectual extreme of the field, LHC phenomenologists are meeting at the Simons Center this week at a SUSY, Exotics and Reaction to Confronting Higgs workshop. They’re discussing very much those nuts and bolts, those of the current state of attempts to analyze LHC data for any signs of something other than the Standard Model. Matt Strassler is there, and he is providing summaries of the talks at his blog (see here and here) At this workshop, still no deep mathematics, but extremely serious engagement with experiment. One thing that’s apparent is that this field of phenomenology has become a much more sober business than a few years ago, pre-LHC, and pre-no evidence for SUSY. Back then workshops like this featured enthusiastic presentations about all the wonderful new particles, forces and dimensions the LHC was likely to find, with one of the big problems being discussed the “LHC inverse problem” of how people were going to disentangle all the complex new physics the LHC would discover. Things have definitely changed.

One anomaly at the SEARCH workshop was Arkani-Hamed’s talk on naturalness, which started off in a promising way as he said he would give a different talk than his recent ones, discussing various ideas about solving the naturalness problem (though they didn’t work, but might be inspirational). An hour later he was deep into the same generalities and historical analogies about naturalness as in other talks, headed into 15 minutes of promotion of anthropics and the multiverse. He ended his trademark 90 minute one-hour talk with a 15 minute or so discussion of a couple failed ideas about naturalness, and for these I’ll refer you to Matt here.

Arkani-Hamed and others then went into a panel discussion, with Patrick Meade introducing the panelists as having “different specialties, ranging from what we just heard to actually doing calculations and things like this.”

Update: Scott Aaronson now has a blog posting about the KITP workshop here.

Update: A summary of the situation from John Preskill is here.

• At HEP blogs you should be reading already, there’s Tommaso Dorigo on 5 sigma (with more promised to come), and Jester on the lack of a definite BSM energy scale. Jester puts his finger on the big problem facing HEP physics. In the past new machines could be justified since we could point to new phenomena that pretty much had to turn up in the energy range being opened up by the machine (Ws and Zs at the SPS, the top at the Tevatron, the Higgs at the LHC). Now though, there’s nothing definite to point to as likely to show up at the energy scale of a plausible next machine. Jester includes a graphic from a recent Savas Dimopoulos talk characterizing the current situation in terms of chickens running around with their heads cut off, which seems about right.
• The black hole information paradox has been around for nearly forty years, with the story 10 years ago that it supposedly had been resolved by AdS/CFT and string theory. For the past year or so arguments have been raging about “firewalls” and a version 2.0 of the paradox, which evidently now is not resolved by AdS/CFT and string theory. I couldn’t tell if there was much to this argument, but the fact that there’s a Lubos rant about how it’s all nonsense made me think maybe there really is something to it. As usual though, my interest in quantum gravity questions that have nothing to say about unification is limited. For those with more interest in this, I’ll just point to today’s big article in the New York Times, and next week’s workshop at KITP where the latest iterations will get hashed out. For more on the challenge this argument poses to the idea that AdS/CFT gives a consistent picture of quantum gravity, see this recent talk by Polchinski.
• For another challenge to orthodoxy from someone at UCSB, Don Marolf has a new preprint out arguing that strings are not needed to understand holography:
  

  Stringy bulk degrees of freedom are not required and play little role even when they exist.

Alok Jha has a piece in the Guardian yesterday about the failure to find SUSY. His conclusion I think gets the current situation right:

Or, as many physicists are now beginning to think, it could be that the venerable theory is wrong, and we do not, after all, live in a supersymmetric universe.

An interesting aspect of the article is that Jha asks some SUSY enthusiasts about when they will give up if no evidence for SUSY appears:

[Ben] Allanach says he will wait until the LHC has spent a year or so collecting data from its high-energy runs from 2015. And if no particles turn up during that time? “Then what you can say is there’s unlikely to be a discovery of supersymmetry at Cern in the foreseeable future,” he says.

Allanach has been at this for about 20 years, and here’s what he has to say about the prospect of failure:

If the worst happens, and supersymmetry does not show itself at the LHC, Allanach says it will be a wrench to have to go and work on something else. “I’ll feel a sense of loss over the excitement of the discovery. I still feel that excitement and I can imagine it, six months into the running at 14TeV and then some bumps appearing in the data and getting very excited and getting stuck in. It’s the loss of that that would affect me, emotionally.”

John Ellis has been in the SUSY business even longer, for 30 years or so and he’s not giving up:

Ellis, though confident that he will be vindicated, is philosophical about the potential failure of a theory that he, and thousands of other physicists, have worked on for their entire careers.

“It’s better to have loved and lost than not to have loved at all,” he says. “Obviously we theorists working on supersymmetry are playing for big stakes. We’re talking about dark matter, the origins of mass scales in physics, unifying the fundamental forces. You have to be realistic: if you are playing for big stakes, very possibly you’re not going to win.”

But, just because you’re not going to win, that doesn’t mean you have to ever admit that you lost:

John Ellis, a particle theorist at Cern and King’s College London, has been working on supersymmetry for more than 30 years, and is optimistic that the collider will find the evidence he has been waiting for. But when would he give up? “After you’ve run the LHC for another 10 years or more and explored lots of parameter space and you still haven’t found supersymmetry at that stage, I’ll probably be retired. It’s often said that it’s not theories that die, it’s theorists that die.”

There may be a generational dividing line somewhere in the age distribution of theorists, with those above a certain age likely to make the calculation that, no matter how bad things get for SUSY and string theory unification, it’s better to go to the grave without admitting defeat. The LHC will be in operation until 2030 or so, and you can always start arguing that 100 TeV will be needed to see SUSY (see here), ensuring that giving up won’t ever be necessary except for those now still wet behind the ears.

For another journalist’s take on the state of SUSY, this one Columbia-centric and featuring me as skeptic, see here.

My colleague Johan de Jong for the last few years has been working on an amazing mathematical endeavor he calls the “Stacks Project”. As boring 20th century technology, this is a work-in-progress document (now nearly 4000 pages), available here. But from the beginning Johan (known to his friends as “the Linus Torvalds of algebraic geometry”) has conceptualized this as an open-source project using 21st century technology, including a blog and a github repository.

As of last night, the Stacks Project has many new features, courtesy of impressive work by Johan’s collaborator on this, Pieter Belmans. I was going to write something here describing the new features and how cool they are, but a much better job of this has been done by Cathy O’Neil, aka Mathbabe (by the way, if you’re not reading Cathy’s blog, you should be…). With her permission, I’m cross-posting her new blog entry about this, so, what follows is from Cathy:

The Stacks Project gets ever awesomer with new viz

Here’s a completely biased interview I did with my husband A. Johan de Jong, who has been working with Pieter Belmans on a very cool online math project using d3js. I even made up some of his answers (with his approval).

Q: What is the Stacks Project?

A: It’s an open source textbook and reference for my field, which is algebraic geometry. It builds foundations starting from elementary college algebra and going up to algebraic stacks. It’s a self-contained exposition of all the material there, which makes it different from a research textbook or the experience you’d have reading a bunch of papers.

We were quite neurotic setting it up – everything has a proof, other results are referenced explicitly, and it’s strictly linear, which is to say there’s a strict ordering of the text so that all references are always to earlier results.

Of course the field itself has different directions, some of which are represented in the stacks project, but we had to choose a way of presenting it which allowed for this idea of linearity (of course, any mathematician thinks we can do that for all of mathematics).

Q: How has the Stacks Project website changed?

A: It started out as just a place you could download the pdf and tex files, but then Pieter Belmans came on board and he added features such as full text search, tag look-up, and a commenting system. In this latest version, we’ve added a whole bunch of features, but the most interesting one is the dynamic generation of dependency graphs.

We’ve had some crude visualizations for a while, and we made t-shirts from those pictures. I even had this deal where, if people found mathematical mistakes in the Stacks Project, they’d get a free t-shirt, and I’m happy to report that I just last week gave away my last t-shirt. Here’s an old picture of me with my adorable son (who’s now huge).

Q: Talk a little bit about the new viz.

A: First a word about the tags, which we need to understand the viz.

Every mathematical result in the Stacks Project has a “tag”, which is a four letter code, and which is a permanent reference for that result, even as other results are added before or after that one (by the way, Cathy O’Neil figured this system out).

The graphs show the logical dependencies between these tags, represented by arrows between nodes. You can see this structure in the above picture already.

So for example, if tag ABCD refers to Zariski’s Main Theorem, and tag ADFG refers to Nakayama’s Lemma, then since Zariski depends on Nakayama, there’s a logical dependency, which means the node labeled ABCD points to the node labeled ADFG in the entire graph.

Of course, we don’t really look at the entire graph, we look at the subgraph of results which a given result depends on. And we don’t draw all the arrows either, we only draw the arrows corresponding to direct references in the proofs. Which is to say, in the subgraph for Zariski, there will be a path from node ABCD to node ADFG, but not necessarily a direct link.

Q: Can we see an example?

Let’s move to an example for result 01WC, which refers to the proof that “a locally projective morphism is proper”.

First, there are two kinds of heat maps. Here’s one that defines distance as the maximum (directed) distance from the root node. In other words, how far down in the proof is this result needed? In this case the main result 01WC is bright red with a black dotted border, and any result that 01WC depends on is represented as a node. The edges are directed, although the arrows aren’t drawn, but you can figure out the direction by how the color changes. The dark blue colors are the leaf nodes that are farthest away from the root.

Another way of saying this is that the redder results are the results that are closer to it in meaning and sophistication level.

Note if we had defined the distance as the minimum distance from the root node (to come soon hopefully), then we’d have a slightly different and also meaningful way of thinking about “redness” as “relevance” to the root node.

This is a screenshot but feel free to play with it directly here. For all of the graphs, hovering over a result will cause the statement of the result to appear, which is awesome.

Next, let’s look at another kind of heat map where the color is defined as maximum distance from some leaf note in the overall graph. So dark blue nodes are basic results in algebra, sheaves, sites, cohomology, simplicial methods, and other chapters. The link is the same, you can just toggle between the different metric.

Next we delved further into how results depend on those different topics. Here, again for the same result, we can see the extent to which that result depends on the different on results from the various chapters. If you scroll over the nodes you can see more details. This is just a screenshot but you can play with it yourself here and you can collapse it in various ways corresponding to the internal hierarchy of the project.

Finally, we have a way of looking at the logical dependency graph directly, where result node is labeled with a tag and colored by “type”: whether it’s a lemma, proposition, theorem, or something else, and it also annotates the results which have separate names. Again a screenshot but play with it here, it rotates!

Check out the whole project here, and feel free to leave comments using the comment feature!

• I confess to mostly finding “philosophy of physics” arguments not very helpful for understanding anything, but for those who feel differently, some new things to look at are a Scientific American article Physicists Debate Whether the World is Made of Particles or Fields or Something Else Entirely, an interview with Jonathan Bain, an interview with Tim Maudlin, a debate between John Ellis, Lawrence Krauss and theologian Don Cupitt about Why is there something rather than nothing?, and the talks at a UCSC Philosophy of Cosmology Summer School. Since the last of these was funded by the Templeton Foundation, it ended with several talks on “Implications of cosmology for the philosophy of religion”. These included a detailed argument that the explanation for the laws of nature is “there is a perfect being”, contrasting this to another argument favored at the Summer School “the multiverse did it”.
• This week the Perimeter Institute will host Loops 13, devoted to loop quantum gravity and other quantum gravity approaches. While it’s also funded by Templeton, the organizers seem to have managed to keep God out of this one.
• At CERN, Amplitudes, Strings and Branes is on-going. Philip Gibbs has an amusing argument that this and Loops 13 are The Same Bloody Thing.
• One thing the LQG and Amplitudes people do share is that some of their most important ideas come from the same person: Roger Penrose (who, but the way, would be a good candidate for the Fundamental Physics Prize, although his distaste for string theory might be a disqualifier). There’s a long interview with him at The Ideas Roadshow, mainly about his “Cyclic Universe” ideas.
• The Simons Foundation has been publishing some excellent science reporting, and now has an online publication they’re calling Quanta Magazine. The latest story there is a very good piece on the search for dark matter from Jennifer Ouellette. The Simons Center at Stony Brook now has a newsletter about their activities.
• Another on-going conference is one of the big yearly HEP conferences, EPS HEP 2013 in Stockholm. CMS and LHCb have impressive new results about rare B decays, timed for this conference. For the details, see Tommaso Dorigo. There are also CMS and CERN press releases.

  Last year similar but less accurate results were advertised as putting SUSY “in the hospital”, which some people objected to, on the grounds that it was already in trouble and this kind of result doesn’t make things much worse. Resonaances had the details, summarizing this a “another handful of earth upon the coffin”. The CERN press office tries to put the best SUSY spin on this that it can:

  One popular theory is known as supersymmetry, SUSY for short. It postulates the existence of a new type of particle for every Standard Model particle we know, and some of these particles would have just the right properties to make up a large part of the dark universe. There are many SUSY models in circulation, and SUSY is just one of many theoretical routes to physics beyond the Standard Model. Today’s measurements allow physicists to sort between them. Many are incompatible with the new measurements, and so must be discarded, allowing the theory community to work on those that are still in the running.

• Finally, for those with mathematical interests who have waded through the above, Terry Tao has a remarkable long expository piece about the Riemann hypothesis, ranging from analytic number theory aspects through the function field case and l-adic cohomology.

Update: For more from Penrose, see this recent talk in Warsaw.

Update: Studies in History and Philosophy of Modern Physics is planning a special issue on the significance of the Higgs discovery, the call for papers is here.