Various Links

Posted on December 15, 2016 by woit

A grab-bag of unrelated topics and links:

  • Continuing the subject of budget cuts from the last posting, I heard today that the NSA is not funding this year the grant program that the AMS has been running for it, called the NSA Mathematical Sciences Program. In typical NSA fashion, no real reason given:

    after much deliberation our senior management has decided that the MSP will not have the resources to make new awards in FY2017.

    Even less information is available than in the case of the similarly mysterious DOE HEP Theory cuts, since all information about the NSA budget, even the total, is classified (although from Snowden and others, it seems that it’s about $10.5 billion).

  • The IHES has a new website.
  • This spring Peter Scholze will give a series of six lectures at the IHES on the latest about the local Langlands conjectures.
  • Via David Roberts, the LMS has some videos about mathematicians here. Kevin Buzzard explains Langlands:

    The Langlands philosophy? Yeah, that’s like Birch-Swinnerton-Dyer on crack, isn’t it?.

  • Tate’s collected works are finally available from the AMS.
  • Turning to physics, there’s a very good new article at Quanta from Natalie Wolchover about the unsuccessful search for proton decay and what this means for grand unification ideas. Glashow has now given up, with the simplest GUTs now conclusively ruled out:

    Glashow, for one, largely lost interest in the whole affair when SU(5) was ruled out. “Proton decay has been a failure,” he said. “So many great ideas have died.”

    Not everyone has given up though, with fans of the “flipped SU(5)” SUSY GUT explaining things this way:

    Barr, one of the originators of the still-viable “flipped SU(5)” GUT model, compared the situation to waiting for your spouse to come home. “If they’re 10 minutes late, there’s simple explanations for that. An hour late, maybe those explanations become a little less plausible. If they’re eight hours late … you begin to worry that maybe your husband or wife is dead. So the point is, at what point do you say your theory is dead?”

    Right now, he said, “we’re more at the point where the spouse is 10 minutes late, or maybe an hour late. It’s still completely plausible that grand unification is correct.”

    Besides the current wishful thinking, this particular model has a strange history. You can read here about how it follows from Vedic Science. Over the years it has been about to come home many times, see this from 2012, which assures us that:

    The CMS and ATLAS experiments have also observed tantalizing hints of the unique signature predicted by the Flipped SU(5) model.

    At this point, it seems to me to be way more than an hour late, time for its nearest and dearest to admit that it’s dead (or maybe has run off with its TM instructor).

  • Also in Quanta, you can read about Janet Conrad and sterile neutrinos here.
  • I don’t always agree with Sabine Hossenfelder about math, but I very much agree with the conclusion of this posting:

    In lack of experimental guidance, what we need in the foundations of physics is conceptual clarity. We need rigorous math, not claims to experience, intuition, and aesthetic appeal. Don’t be afraid, but we need more math.

  • There’s a Recent Developments in Fields, Strings, and Gravity conference going on this week at the new Center for Quantum Mathematics and Physics at Davis.
  • Videos of the talks at the recent John Schwarz 75th birthday conference at Caltech are available here.
  • Multiversal Journeys is an organization devoted to promoting theoretical physics, with a heavy dose of multiverse mania as part of their story. They have a new book coming out, Quantum Physics, Mini Black Holes and the Multiverse, supposedly “Debunking Common Misconceptions in Theoretical Physics”. It seems that one of these common misconceptions is that the multiverse is pseudo-science. To fight this, they’ve also produced a promotional video.
  • Bert Schroer has an interesting preprint with a lot of material about Rudolf Haag and algebraic quantum field theory.
  • Another intriguing preprint recently out is from Arkani-Hamed and collaborators. In the past Arkani-Hamed has been vehement about gauge symmetry just being a worthless redundancy in our description of physics, for instance stating:

    What’s as a misnomer called gauge symmetry, whose beauty is extolled at length in all the textbooks on the subject, is completely garbage. It’s completely content free, there’s nothing to it.

    In the new paper, instead of gauge invariance being useless, there’s a conjecture that locality and unitarity, instead of being fundamental principles, follow from gauge invariance.

    There’s a long tradition in the philosophy of physics literature of arguing over whether gauge symmetry is a fundamental idea or a useless redundancy. I’m on “fundamental idea” side, but of course exactly what the role of gauge symmetry is in fundamental physics is something that we have yet to fully comprehend.

Posted in Langlands, Multiverse Mania, Uncategorized | 29 Comments

HEP Theory Letter

Posted on December 8, 2016 by woit

A couple weeks ago a large group of US HEP theorists wrote a letter to the DOE High Energy Physics Advisory Panel (HEPAP) (available at page 7 here) expressing alarm at trends in DOE funding of HEP theory, ending with

We formally request that a subpanel of HEPAP be formed to investigate and better understand this damaging trend and to make recommendations to address its consequences and restore a thriving Theory program, and we strongly urge that HEPAP support measure to rebuild and maintain the prominent and world-leading standing of US High Energy Theoretical Physics.

The letter claims that since 2011 the overall DOE HEP Theory program has been cut by 17%, with the university component of this cut by 30%. It also claims that 25% of DOE-supported university theorists have had their funding cut off in the last four years, with the number of postdocs going down by about 30%.

At last week’s HEPAP meeting there was a discussion of this, but I don’t know what was decided. Some numbers presented there indicated that from FY2013-2015. the DOE theory budget went from $51.2 million to $49.32 million. The net number of funded PIs was reduced by more than 10% (25 out of about 230), with 52 PIs dropped, 27 new ones coming in. The conclusion of that presentation was that “The theory program in its current state cannot be described as thriving.” The emphasis in the letter and this presentation on “thriving” is a reference to one of the P5 recommendations that is supposed to be governing how the DOE HEP budget is allocated:

The U.S. has leadership in diverse areas of theoretical research in particle physics. A thriving theory program is essential for both identifying new directions for the field and supporting the current experimental program.

The most detailed recent information I can find about the DOE HEP theory budget is in this presentation from August. It shows a decline from FY10 to FY16 from $53.09 million to $46.69 million, with most of this in the component going to university groups, which went from $27.25 million to $21.765 million. The current number of postdocs supported is listed as about 125 (100 at universities, 25 at the labs), the number of graduate students is about 120.

Concern about this decrease in funding first became public two and a half years ago (see my blog post here) with Sean Carroll’s blog post describing a “calamity”. Various HEPAP presentations warned physicists about the dangers of public complaints and these died down for a while, but the continuing cuts to the university component of theory funding seem to have led to the decision to send this new letter.

An odd part of this story is that it’s unclear why this decision to reduce DOE HEP theory university funding significantly was made. It’s true that the overall DOE HEP budget has been cut over the same period (from $810.5 million in FY10 to $795 million in FY16) but unknown why the university theory component was cut 20% over this period while the overall cut was only 2%. Note that none of these numbers are adjusted for inflation.

It would be very interesting to hear comments from anyone who knows more about what is going on here. The usual generic comments that government spending is bad will be deleted. Keep in mind that the amount of money at issue here is (2.7% of the HEP budget, .00058% of the total federal budget) very small on the scale of government funding of science, and now ever small on the scale of private science funding (the Simons Foundation alone last year gave out $233 million in grants).

Update: A full copy of the letter with all signatures is here. An explanation of where the numbers in the letter come from is here.

Posted in Uncategorized | 28 Comments

Anomaly!

Posted on December 6, 2016 by woit

Tommaso Dorigo’s new book Anomaly! Collider Physics and the Quest for New Phenomena at Fermilab has just become available. I highly recommend it to anyone with an interest in high energy physics who wants some insight into how collider experiments are done. Dorigo is a well-known blogger, with the best (as well as most entertaining) blog there is about the experimental side of high energy physics. If you’re not following his blogging, you should be.

The nominal topic of the book is research conducted at the Tevatron by the CDF experiment during the 80s and 90s, into the early 2000s. Some of the specific well-known CDF results discussed in detail include measurement of the Z mass and the discovery of the top quark. The material about the top quark discovery comes closest to the kind of thing you find in other books. It’s a very well-done insider’s account of the story of an important discovery. I don’t know of a better place to read about the top quark search and how it finally succeeded.

One of the most unusual aspects of the book, in evidence in the top quark section and throughout the rest, is that it goes much deeper into an explanation of how collider experiment physics analyses are actually done than is usual in a popular or semi-popular book. Besides the insider’s local color and insights into the personalities involved, there’s quite a bit of discussion of the technical issues of the subject. This is a subject involving thorny issues of how best to reconstruct the properties of particles coming out of collisions, and finding clever new ways to deal with these while avoiding subtle pitfalls is a central problem, one outsiders normally don’t get to hear about.

The other unusual aspect of the book is that it doesn’t just discuss success stories of striking discoveries (of which there hasn’t been much between the top and the much later Higgs discovery at the LHC). One of the main activities of the field has been the search for “anomalies”, experimental results that disagree with the Standard Model and point to new physics. The problem is that finding anomalies is common, but they almost certainly will turn out to be due to some problem with the experiment or its analysis (such problems are always much more likely than revolutionary new physics).

One of the stories of an anomaly described extensively is that of an excess of high transverse energy jets, something that one might expect to see if quarks had some substructure (“preons”). Here the problem turned out to have a lot to do not with the experimental result, but with the theoretical modeling of what to expect from QCD. Another example is the story of “superjets”, events involving a W and 2 or 3 jets, with unusual properties.

For the “superjets” and for other anomalies, a favorite explanation was to invoke supersymmetry, since supersymmetric models predict a large range of different kinds of new particles, and one might hope that any anomaly is due to one of them. Dorigo has a few stories about theorists I hadn’t heard, in particular that of a fall 1995 letter signed by many prominent theorists (except Howard Georgi, who refused to sign). Despite ongoing efforts to look for superpartners, all of which had been unsuccessful, the feeling of the theorists was that the Fermilab experimenters weren’t trying hard enough. The letter was sent to the Fermilab director as well as the CDF and DZERO spokespersons. It explained what a great idea supersymmetry was, and ended with

We, the undersigned, believe that Fermilab has unique detection possibilites for supersymmetry, and urge you to direct your laboratory’s efforts in that direction, and ask the leaders of the collider detector collaborations to intensify their search for massive superpartners.

For more than two decades now, such searches for superpartners have been one of the dominant activities of collider experiments, with well-known negative results.

Finally, another important and unusual theme that runs through the book is the question of how to statistically characterize the significance of an anomaly. This is a topic where Dorigo is very much an expert, recently heading the CMS Statistics Committee.

Anomaly! is both a great tale of how science is really done, and an unusually insightful exploration of the crucial question of how one evaluates the significance of hints of new experimental discoveries. This question is of central importance now as the LHC gathers and analyzes data in a previously unexplored energy range. There are undoubtedly anomalies galore being studied by the LHC scientists, almost all of which will never be heard of by the public, as the experiments cautiously work to eliminate every possible conventional physics explanation for the anomaly. The 750 GeV diphoton bump of the past year is one example of an anomaly that made it out to a public announcement, with its disappearance in this year’s data making clear why the experiments are so cautious. You can’t find out about these ongoing stories, perhaps for good reason, due to the policies of how collider experiments are run, but now you can buy a copy of Anomaly! and at least read about how things played out in the previous generation of such experiments. This background should be helpful to make sense of what is going on if and when (March?), the next LHC anomaly gets reported.

Posted in Book Reviews | 5 Comments

Breakthrough Prizes 2017

Posted on December 4, 2016 by woit

The 2017 Breakthrough Prizes have just been announced, here are the winners and a few comments. Note that I’m leaving the usual singing of praise of the many virtues of the laureates to others, since there should soon be a lot of such stories appearing. Instead I’ll concentrate on issues that aren’t getting as much attention.

Already announced back in May, there is a special Breakthrough Prize for the LIGO collaboration: \$1 million to be split by Drever, Thorne and Weiss, \$2 million to be split by the other 1012 members of the LIGO collaboration. Quite likely Drever, Thorne and Weiss will get the Nobel Prize next year (the LIGO result was published too late for consideration this year). A very good thing about the Breakthrough Prize though is that it is given to the entire collaboration, with awards going to every one. They have done similar things in the past, with awards to the LHC experiments, to neutrino experiments and to the accelerating universe supernova experiments.

The Nobel Prize in Physics and most other such prizes are never awarded to a group, just (at most three) individuals. In an era of large scientific collaborations this isn’t fair, with all the recognition and prize money going to some small set of people, nothing to anyone else. I’m glad to see that, for these experimental prizes, the Breakthrough Prize has been following a different model.

The 2017 \$3 million Breakthrough Prize in mathematics goes to Jean Bourgain of the Institute for Advanced Study in Princeton. I’m not particularly familiar with his work, you’ll have to read about it elsewhere. He is a well-known figure in the math community, already a recipient of many prizes including the Fields Medal, Shaw and Crafoord prizes.

I’ve never been convinced that this mathematics $3 million prize is a good idea, since it typically goes to someone like Bourgain who, besides being an essentially randomly chosen lucky winner from a sizable pool of similarly distinguished mathematicians, already has prize money and a very well paid position with minimal responsibilities. This isn’t going to help him do better mathematics. A much better way to spend the money would be on endowing new permanent academic positions in mathematics, allowing more talented young people to have a career in mathematical research.

The philosophy behind the Breakthrough Prizes, very visible in the glitzy award ceremony (you can watch it on the National Geographic channel this evening, 10pm EST), is that scientists don’t get the kind of fame and stardom they deserve, so Milner and Zuckerberg are going to help fix this. What motivates good mathematics though is something very different, and bringing to mathematics more of the Hollywood star system is not going to improve mathematics research. In recent decades much of US society has moved to a brutal winner-take-all system. While our Silicon Valley overlords have flourished under this, I don’t think their bringing more of it to scientific research is a good idea.

While one can argue that the huge checks to mathematicians don’t have any particular negative effect, the situation in theoretical physics is quite different. Since the original laureates chosen by Milner, the yearly prizes that have gone to theorists (as opposed to the experimental prizes mentioned above) have all gone to string theorists (there was also a special prize given to Hawking). First there was Polyakov, then Green and Schwarz, and this year the $3 million Breakthrough Prize in Physics goes to three more string theorists: Joe Polchinski, Andy Strominger, and Cumrun Vafa.

In the case of string theory, I don’t think one can seriously argue that the field suffers from a lack of public attention. Mountains of hype about string theory have been produced in the last 32 years, seriously damaging the field of theoretical physics. This year’s prize adds to that mountain, with hype-ridden citations [press materials] backing the glitzy ceremony and million dollar checks. The language tries to turn physics research Hollywood: for instance, relativity and quantum theory are “the two superstar theories of modern physics”.

Perhaps the worst aspect of these prizes and citations [associated explanatory materials] is that they often hype and reward failed theoretical ideas: if your ideas work maybe you’ll get part of a \$1 million Nobel Prize, but if they fail, as long as they’re about string theory, you’ll get part of a \$3 million Breakthrough Prize. The citation [description of “Contributions”] for Strominger includes this about string theory:

Andrew Strominger played a major role in its emergence when he showed that it not only reconciles quantum mechanics with gravity, but can also contains within it the other observed particles and forces.

This refers to Strominger’s early work on Calabi-Yau compactifications, while not mentioning that this idea has never worked out.

These prizes are often awarded for ideas about the black hole information paradox, independent of whether these ideas work. Maldacena’s citation from 2012 tells us that he got the award partly for “resolving the black hole information paradox”, and the Strominger citation [description of “Contributions”] tells us that “His work hints at a solution to the famous ‘black hole information paradox’”. Polchinski is rewarded for a

big idea, deriving from the principles of quantum mechanics: ‘firewalls’ –blizzards of high-energy particles around black holes. The existence of firewalls would signal a fault line in the foundations of physics: at least one of the two superstar theories of modern physics – relativity theory and quantum theory – would have to be incomplete at a fundamental level.

Anyone reading this is unlikely to figure out that the significance of Polchinski’s “big idea” is that it purports to show that the solution to the paradox supposedly given by Maldacena actually doesn’t work (not surprising, since it was never more than a speculation). If you’re a string theorist, you don’t actually need to solve a problem to get a prize: speculation about what the solution to a problem might be is good enough, as is finding problems with the speculations of other string theorists. This sort of thing does nothing to improve the difficult situation of current theoretical physics, quite the opposite.

Tomorrow there will be a symposium at UCSF featuring 15 minute “TED-style” talks giving “pragmatic versions” of what could be done during the next ten years. For string theory, the blurb for the talk or talks is

Medium-term goals of string theory, from resolving the paradoxes of black holes to estimating the lifetime of the universe.

After a cycle of two prizes for resolving the information paradox and then unresolving it, I suppose it’s a reasonable goal for string theorists to go through another cycle or so during the next ten years. The idea of using string theory to “estimat[e] the lifetime of the universe” anytime soon goes beyond any of the usual hype, so we’ll have to see what that’s about tomorrow.

Update: Smaller \$100,000 “New Horizons” prizes, some split in various ways, went to 6 theoretical physicists (Asimina Arvanitaki, Peter Graham, Surjeet Rajendran, Simone Gombi, Xi Yin and Frans Pretorius) and 4 mathematicians (Mohammed Abouzaid, Hugo Duminil-Copin, Ben Elias and Geordie Williamson). Congratulations to all, especially to the Columbia contingent (Mohammed is a faculty member now, Ben was a grad student here, and TA one year for my representation theory course).

Update: Some of the language quoted above as part of the citations for the string theory awards was actually in a separate section of materials distributed to the press called “Contributions”, which gave more specifics of what the award was being made for. I’ve changed the wording above to more accurately reflect this.

Update: Just watched the Breakthrough Prize ceremony on TV. Very nice short portrait of Jean Bourgain and his work, and remarks by him. The string theorists were right at the end, and the DVR cut off in the middle of a clip of outrageous hype from them (I guess the ceremony went slightly longer than scheduled).

Update: Nature has coverage of the prizes here, emphasizing the award to Polchinski for firewalls, with some justification from Milner.

Update: Livestream of the symposium is here. Polchinski and Strominger will be talking about black hole information paradox/string theory, Vafa will describe “a research program for putting rigorous bounds on the lifetime of our universe, by studying the range of possibilities permitted by the laws of string theory.”

Posted in Uncategorized | 72 Comments

Various Links

Posted on November 22, 2016 by woit

A few pre-Thanksgiving items:

  • International Journal of Modern Physics A has a new issue with “Featured Topic” part I of a discussion of the proposed Chinese supercollider project. The high profile contributions are from C. N. Yang, China should not build a supercollider at this time, and a response from David Gross: Why China should build the Great Collider. Both I think do a good job of making the case for and against the project, with the central question that of the high cost. If this was a $1 billion project there would be no question it would get done, and if it was a $100 billion project it could never happen. The problem is that the order of magnitude is $10 billion.

    There are some other contributions to the debate, including sensible pro-collider pieces by Yifang Wang and Weimin Wu. There’s also a bizarre piece by Henry Tye, making an ad hominem argument against Yang, based on the fact that in 1980 Yang was skeptical about the future of high energy physics. I’m afraid that this doesn’t work very well as an argument against Yang, whose prediction of no post-1980 breakthroughs looks unfortunately prescient these days.

  • According to the New York Times, one possibly imminent non-HEP breakthrough is a Microsoft quantum computer. Their project grew out of one they funded led by topologist Mike Freedman.
  • Last weekend there was a celebration at Caltech of John Schwarz’s 75th birthday. No slides or video of talks it seems. I’ve wondered what Susskind’s take on supersymmetry is these days, so curious what might have been in his talk entitled “Supersymmetry and the Limits of What We Know”.
  • Howard Burton was the founding director of Perimeter, helping to get it off the ground and turn it into the success it has become (Sabine Hossenfelder here notes that the term of the current director Neil Turok is up and wonders who is next). In recent years Burton has been running something he calls Ideas Roadshow, and now has a new blog called In Search of Refinement. He writes about a recent event with Roger Penrose, discussing his new book, and has kind things to say about my review of the book. Ideas Roadshow now has accumulated a significant number of interesting interviews, worth your while if you’re looking for high-quality but not free internet content to support.

Update: One more. Yet more private funding for US scientific research. The New York Times reports on the Simons Foundation Flatiron Institute, a planned $80 million/year, 200 employee research institute. The focus will be on computational work, and doing better science by freeing scientists from having to apply for grants.

Posted in Uncategorized | 21 Comments

What Math Do You Need For Physics?

Posted on November 17, 2016 by woit

Chad Orzel has a very sensible piece at Forbes, headlined What Math Do You Need For Physics? It Depends, which addresses the question of what math a physicist like him (experimental AMO physics) really needs. I’m glad to see that he emphasizes the same basic courses my department offers aimed at non-majors:

  • Multivariable calculus
  • Differential equations
  • Linear algebra

together with statistics (which here at Columbia is handled by a separate department). He disses complex analysis, for reasons that I can understand. That’s a beautiful subject, and the results you can get out of analytic functions and contour integration are often unexpected and seemingly magic, but they’re not of as general use as the other subjects.

One subject he doesn’t mention that I would argue for is Fourier Analysis, which is the class I’ll be teaching next semester. That’s an incredibly useful as well as profound subject which every physicist should know, but it is true some of its basics often gets taught in other courses (for example in ode courses as a method for solving differential equations).

Orzel starts off with an amusing discussion of a physics version of “Humiliation”, admitting that he’s never used or really worked through a proof of Noether’s theorem, widely considered “the most profound idea in science”. I’ve argued here for the Hamiltonian over Lagrangian method, in which case a different set of ideas about symmetry is fundamental, with Noether’s theorem playing no role. In the Hamiltonian case symmetries are generated by functions on phase space, and finding the function that generates any symmetry is a matter of Poisson brackets (as an experimentalist, maybe Orzel has never calculated a Poisson bracket either though…).

One says that a function F on phase space generates an infinitesimal transformation if such an infinitesimal transformation changes the function G by {G,F} (the Poisson bracket of the functions G and F). A basic example is the Hamiltonian function, with {G,H} the infinitesimal change of G by time translation, or in other words, Hamilton’s equation
dG/dt={G,H}
When {H,F}=0, we say that the infinitesimal transformation generated by F is a symmetry, since H is left unchanged by such transformations. Using the antisymmetry of the Poisson bracket, this can also be read as {F,H}=0, with Hamilton’s equation then the conservation law that F doesn’t change with time.

All this seems to me much more straightforward than the Lagrangian Noether’s theorem approach to symmetry transformations and conservation laws. My own analog of Orzel’s admission would be admitting (which I won’t do) how long it took me in life to understand this fundamental point (I blame my teachers).

For lots and lots more about this, see chapters 14 and 15 here.

Posted in Uncategorized | 53 Comments

String theory might be about to finally be killed off

Posted on November 13, 2016 by woit

News site TechEye is reporting that String theory might be about to finally be killed off, with a story that starts off

The world’s top boffins are debating finally killing off one of the more elegant scientific theories about the nature of reality.

This isn’t exactly the most reliable information source, with one problem that the story is about supersymmetry, with the only connection to string theory this:

For ages the world’s cleverest physicists have been divided over the concept of supersymmetry – a theory which stipulates that all known fundamental particles have heavier, supersymmetric counterparts called sparticles. It appears to be based on the theory that the universe is made out of string which was teased into shape by cats which are potentially dead or alive [are you sure about this? Ed.]

The writer seems to have gotten the material for the story from a more reliable source, the Economist, which recently had A bet about a cherished theory of physics may soon pay out. That story starts by explaining about Ken Lane’s 1994 bet with David Gross that the LHC would not see supersymmetry. As mentioned here, this year’s data should be enough to resolve the question they were betting about. It is likely that results from SUSY searches using most of this year’s data will be presented at the usual mid-December LHC Jamboree at CERN, and unless there’s dramatic news my sources are keeping from me, these results will be negative.

The bet was for an expensive dinner at Girardet’s, a three-star Swiss restaurant which has now closed, and

Dr Lane says it is time for Dr Gross (who won the Nobel prize in 2004) to cough up—if not with dinner at Girardet’s then at another suitably ritzy venue. After receiving no response to several e-mail prompts, however, Dr Lane is growing impatient. “David appears to be welshing [misuse of language, see here] on our bet,” he says.

but

Dr Gross is not ready to concede quite yet. The data are in, but their analysis is not complete. “It looks like I will lose this bet by the end of the year,” he says, “but we should await the word from the experimenters themselves.” (Dr Lane says the original terms have been met and Dr Gross should throw in the towel.)

As for whether this really kills off SUSY, there’s a pithy quote from Sabine Hossenfelder:

Sabine Hossenfelder, a theoretical physicist at the Frankfurt Institute for Advanced Studies, is one of many who think it is time for theorists to focus on other problems—how gravity behaves at the very small scales of quantum mechanics, for instance. If the LHC finds no trace of sparticles in this year’s data, she believes the last thing the field needs is another round of Susy model adjustments. “That’s not science,” she says. “That’s pathetic.”

Posted in Uncategorized | 23 Comments

Entanglement, the Multiverse and the Universe

Posted on November 10, 2016 by woit

“Entanglement” is the current buzzword of physics, here are two new stories featuring this:

Back in 2013 one could read lots of claims in the media that “Hard evidence for the multiverse” had been found, based on “effects of quantum entanglement between our horizon patch and others”. These claims were discussed on this blog (with a response from the authors here). A new paper by Will Kinney has now been published in JCAP, including the following conclusion about such claims:

It is worthwhile to discuss in general the “concrete predictions” originally claimed by the authors of refs. [1,2], since several key claims do not survive even cursory scrutiny. For example, the discontinuity in the effective potential claimed to be correlated with voids and the CMB cold spot does not appear to in fact exist: for all physically relevant values of the parameters V0, λ, and b, the modulation F(φ) is a smooth function, with no characteristic discontinuities which would explain features in the power spectrum. Perhaps more importantly, the form of the effective potential resulting from landscape entanglement is completely dependent on the choice of inflationary potential V(φ), which is itself an arbitrary free function. One could just as consistently choose the underlying inflationary potential in the absence of landscape corrections to be the same as the effective potential (2.7)! In this sense, the landscape model is no more (or less) predictive than single-field inflation itself, and most of the claimed predictions of the entanglement model turn out not to have been
predictions at all. However, any considerations of theoretical consistency are a moot point: even if one takes the claimed predictions at face value, almost all of them are ruled out by Planck. Experiment always supersedes theory, and the model does not match the data.

This paper has an unusual story behind it, with an author of the work it criticizes trying to keep it off the arXiv. For more about this, see here and here.

Another entanglement story that is getting some press attention this week is this paper by Erik Verlinde, with its associated press release, explaining that we may be “on the brink of a scientific revolution”. I’ll have to avoid trying to give an explanation of the physical argument of the paper, on the grounds that I don’t understand it, partly because there seems to be no underlying physical model here. The basic idea is stated as replacing dark matter by

an elastic response due to the volume law contribution to the entanglement entropy in our universe.

but someone else will have to explain exactly what that means. Maybe I’m missing it, but I don’t see anywhere in the paper a suggested experimental test of the theory. Someone much more expert than me is needed to explain whether the picture of this paper is consistent with the known astrophysical and cosmological evidence usually interpreted as dark matter/dark energy.

Posted in Multiverse Mania | 22 Comments

The Day After

Posted on November 9, 2016 by woit

The last few months have not been helpful for my sanity (and I think for that of a large number of other Americans). My three-point program to return to better mental health is to:

  • Write one last blog post about what has been going on in the US (with comments off, again for mental health reasons).
  • Stop thinking about this topic and stick to thinking and blogging about math and physics.
  • Get out of this country for a while, heading to Paris the day after Thanksgiving and hiding out there for a week or so. While there, may do some research into what the current French policy is on political refugees.

On the question everyone is asking themselves (what will Trump do?) I have no idea and suspect he doesn’t either. Many around him and in the Republican party do have definite ideas about this. Their agenda will be to use their party’s unparalleled control of the US government at all levels, together with his executive power, to force changes dictated by their ideology. Either Trump will go along with this, or he’ll change and come up with his own agenda going beyond just that of getting more attention for himself.

On the question of how we got here, I think my previous blog post stands up well given what data I’ve seen from the election returns. Most of the explanations one hears of Trump’s success don’t hold up if you look at exit polling numbers:

  • Sexism: more white women voted for Trump than for Clinton.
  • Racism: many counties that went solidly for Obama in the past went to Trump this election. Many Trump voters last voted for an African-American President.
  • Revolt of the rural poor whites: While New York City went heavily to Clinton, nearby Suffolk County on Long Island, with a median family income of $100,000, went for Trump.
  • Ignorance, lack of education: Most white college graduates voted for Trump.

There is however a common thread in most stories I’ve read that let Trump supporters say why they were voting for him: they hated Hillary Clinton and found her dishonest. Polls show that back in early September, when asked “who is more honest and trustworthy?” Clinton and Trump were tied (45/45). By the week before the election, the numbers were (38/45): eight percent more of likely voters thought Trump was honest than thought Clinton was. Whatever you think of Hillary Clinton, the idea that Donald Trump is more honest is quite simply insane. The central question of how we got to a Trump presidency is to understand how this destruction of Clinton’s reputation was accomplished. What makes this tricky is that there was such a huge campaign from all sides to do this, including not just the usual Republican politics of personal destruction machine (Drudge Report, Breitbart, Fox News), but a wide array of actors on the center and the left, including:

  • Julian Assange and Wikileaks, quite likely fronting for Russian secret services.
  • All sorts of lefty news sources, too many examples to pick. Susan Webber who runs Naked Capitalism today is gleeful at the Trump win, and hopes that this is what we’ll soon see:

    There is one more Trump campaign promise that will serve as an important early test of his seriousness as well as his survival skills: investigating Clinton. Even if Obama pardons her, as our Jerri-Lynn Scofield has predicted, it will be critical for Trump to carry out a probe of the Clinton Foundation’s business while Clinton was Secretary of State.

  • The New York Times, which for months nearly every day published an above-the-fold front page news article attacking Clinton’s ethics, with several reporters (Amy Chozick, for one) tasked to make it their full-time assignment to produce such stories. While their opinion writers were mostly more restrained, there’s the bizarre case of Maureen Dowd who for 25 years has been writing literally hundreds of pieces about what she feels is ethically wrong with Hillary Clinton. On the Sunday before the election the Times ran not one but two pieces by Dowd attacking Clinton: a shorter one in the op-ed section, and a longer one in the Magazine section.

Together with the onslaught of right-wing “News” attacking Clinton’s honesty, it is not surprising that more voters decided Trump was the honest one, or that this likely was enough to get him elected (with a minority of the popular vote).

One way to describe what has happened is that this was the first real social media election, with most people getting the information they used to decide who to vote for from Facebook and other internet sources. Many if not most of these have no interest in what is actually true. Many are dominated by a reality TV ethos of picking out someone for others to attack, appealing directly to the ugliest part of the monkey brain we are all descended from. This is not just the province of the Right, with the Left just as happy to join in the ugliness. Everyone can play and get satisfaction of their darkest needs. The winner will always be the con artist monkey with the best dominance displays.

Trump was always going to win an election campaign fought on these grounds, and that’s what this one was. I have no idea of how to stop this from being the future of US democracy. If you’re not from the US, maybe you can take action to ensure that your society does not follow ours down this path.

Update: I’m not seeing many other analyses of what happened this election that I agree with. Here’s one.

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Vote!

Posted on October 30, 2016 by woit

Normally I avoid politics here, but these are not normal times. What follows is a request to my US readers, followed by some general remarks about the disturbing state of US democracy. Sorry, but if you want to discuss any of this, it will have to be elsewhere (internet comment sections are part of the problem…).


To those not planning on voting for Donald Trump:

  • If you’re planning on voting for Hillary Clinton: please be sure to get out and vote, by early voting if available in your state or on Election day. This is extremely important, with the election likely decided by who cares enough to turn out and vote.
  • If you’re planning on not voting: please rethink this. One can in many elections make a reasonable case that the differences between the candidates aren’t great, so, why bother? If there ever were a US election where that was not true, this is it.
  • If you’re planning on voting for a third-party candidate: again, that might make sense if the differences between the two viable candidates were not great, but that is absolutely not the case here. More specifically, if you’re a progressive planning on voting for Jill Stein, please look at what happened in 2000. People who did the same thing in Florida (voting for Nader then) gave us George W. Bush as president, which was a disaster for the progressive cause. I also urge you to look deep within your heart and ask yourself whether your behavior is a realistic engagement with the world, or self-involved moral posturing.


To those planning on voting for Donald Trump:

Please don’t. I see two main arguments for doing this and I think they’re both misguided.

  • You agree with Trump more than Clinton on important policy issues. Whatever policy issue you have in mind, I think if you look into it you’ll find that whatever Trump says now, at some other point he was saying something different. There’s little evidence Trump has fixed views on any policy issue (other than the desirability of better tax treatment for real estate development projects). If you think Trump will, for instance, appoint Supreme Court justices that share your moral values, note that he has reportedly told Peter Thiel that he would like to appoint him to the Court. Thiel is a gay, radical libertarian Silicon Valley billionaire from San Francisco with highly eccentric views. I doubt you share his moral values (since virtually no one else does, right, left or center).

    Note added: This same argument applies to those opposing Clinton and supporting Trump’s election on grounds such as “she’s a war-mongerer, unlike Trump”, since (on some days) Trump claims to oppose US military interventions abroad. If you really believe that “Make America Great” means Trump will institute a policy of restraint on the use of the US military, I think it will likely be just a few weeks into the Trump administration before you find out that you, like your right-wing brethren in flyover country, have been conned.

  • You’re angry at well-off coastal elites who you feel look down on you and your culture, and you want to spit in their face by voting for Trump. If so, you are quite right to feel the way you do. From a lifetime spent among such elites I can tell you that, yes, they do look down on you. Most people here in New York City probably do think you’re an ignorant racist. Your problem though is that Donald Trump is one of us. He’s a well-off New Yorker through and through, looks down on you every bit as much as others. If elected he will govern in the interest of his tribe, not yours. If you think otherwise, you’ve been conned. All you will accomplish by a vote for Trump is to convince people in New York, Washington D.C. and California that you really are even more ignorant than they thought, a racist fool taken in by an obvious con.

How did we end up here?

Whatever happens, I think the huge question facing US democracy is that of how, in an election contest between a competent, honest centrist candidate and an unqualified con artist, we’ve ended up with the majority of the electorate convinced that the first of these is the one with serious ethical problems. American politics has become a reality TV show, with the plot line all about convincing people that a contestant is unethical and dislikable, and so should be voted off the island.

That the right has pursued this tactic against the Clintons since the early 90s is not surprising, since it’s much more effective than arguing the issues. What’s destroying US democracy though is not just one side’s decision to do this, but that the other side, instead of fighting back, has been joining in. The most outrageous example of this is the Clinton email server “scandal”, which is and always has been an absurdity. The attacks on Hillary Clinton’s character based on this have not come just from the right, but also from the left. I every so often look at the Drudge Report, as well as lefty sources (The Intercept, Firedoglake=Shadowproof, Naked Capitalism, etc), and, on this topic, you can’t tell the difference between right and left.

Most damaging though is the behavior of the mainstream media, in particular that of the New York Times, whose coverage of this issue has been atrociously unfair to Clinton. This is not new behavior for them, it goes back to the first Clinton administration, during which they promoted endless similar nonsense (Travelgate, Whitewater, etc., etc.). At the time I found it hard to understand why they were doing this, with one conjecture that it had to do with reporters and editors harboring some sort of resentment, intent on taking down the Clintons a notch (“they think they’re so great, we’ll show them, expose their dirty laundry”).

More recently I’ve come to the conclusion that what’s going on here has to do with the world-view of much of the liberal, educated class that I’m a part of. After some success at addressing ancient problems of racism, sexism, homophobia and the like, many have become impossibly self-righteous and devoted to moral posturing, intent on ferreting out reasons to “call out” others and show their moral superiority.

When political arguments are about issues, they’re often not very rational and it has always been thus. What has changed in the US is that political arguments are now dominated by obsession with the supposed moral failings of others. We’re experiencing a perfect storm of the demagoguery of the right meeting the obsessive self-righteousness of the left, all mediated by journalists who see their primary role as taking down and exposing the supposed moral failings of our leaders. I don’t think we’ve seen this before in our history, and it threatens to upend the basic premises of a working democracy.

It’s very hard to know what kind of craziness we’ll have to deal with if Trump is elected. His agenda is purely that of getting attention for himself and “winning”, I doubt even he has any idea what he’ll do if he wins. On the other hand, unfortunately it’s all too clear what’s going to happen if Clinton is elected. The Republicans will launch endless investigations and attacks on her character in an attempt to make sure her presidency is not a success. The left will join in, and the New York Times and much of the rest of the media will nearly every day feature a new story about what is wrong with Hilary Clinton and with whoever joins her administration and attempts to govern the country in the best interest of its citizens. I don’t see see how this fever breaks, and it’s very hard not to see bleak days ahead for this country.

Update: From talking to various people I realized that one reason some Democrats and those on the left don’t see the “top secret email” business as being as absurd as I do is that they have no idea what these emails were. For that story, see this from the Wall Street Journal and this from the Washington Post.

One reason many people may not be informed about this is that they get their news from the New York Times, where the only mention of this I can find is a snide remark in this story.

Update: Based on some emails from people misreading this posting, it seems I have to make the following clear

  • I DON’T think Trump supporters are ignorant racists.
  • I DON’T think Peter Thiel is immoral (eccentric ≠ bad).

I DO think that

  • Left-wing news and commentary sites
  • New York Times political reporters and editors, together with others at mainstream media outlets
  • Jill Stein and people who support her candidacy

have joined the right in an unholy alliance to try and discredit Clinton, based on completely absurd accusations regarding her use of email. This has led to a serious danger that the US will elect a con artist and fascist demagogue as President next week, or, failing that, destroy hopes for a successful Hilary Clinton administration.

Update: A correspondent points out that I haven’t addressed one reason some on both the Left and the Right (including those at the lefty websites I mentioned) are supporting Trump and trying to destroy Hilary Clinton. They believe that the advent of Trump will “break open the current oligarchy’s Pandora’s box”, with the destruction of the US democratic system making way for a wonderful new system that will grow and flourish in the wreckage. I didn’t mention this nihilist argument for Trump because there is no rational argument against the desire to deal with a problem by smashing everything around one. Sure, that will work, it will get rid of what is bothering you, you’ll feel better and, as long as you’re well enough off, other people will be the collateral damage hit by the debris, as well as those that have to clean up the mess.

Those who think this way though should at least be honest that that’s what they want, and not hide behind dishonest demonization of Hilary Clinton over bogus accusations about her email. The left’s joining with the Republican party to weaponize dishonest accusations about ethics and use those to bring down whoever they disagree with is something that will live on and make sure that what emerges from the wreckage will be even uglier than what was destroyed.

I also added something above, making clear that the arguments to Trump supporters also apply to his Leftist ones.

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