New For 2012

To celebrate the new year, I’ve finally gotten around to updating my home page, and have updated the blog theme to the latest wordpress default.  I’ve added an “FAQ” feature, which is still under construction and should get additions as I find time.  Please let me know of anything that doesn’t work.

This coming semester I’ll be teaching the second half of our graduate course on Lie groups and representations, following on from Andrei Okounkov’s first semester. A tentative syllabus is here, and I hope to find time to update some of my older lecture notes as well as write some new ones.

The time I’ve spent the last couple years trying to learn about the Langlands program has finally gotten me to the point of thinking I understand enough to write something sensible about what the relationship might be between automorphic representations and quantum field theory. I’ll be working on that and preparing the graduate course for the next couple weeks.

One thing that was extremely helpful was Dick Gross’s lecture series here last semester. Video of the lectures is on YouTube here. Gross is an incredibly good lecturer, and this series was aimed at explaining exactly many of the things I’ve been having trouble understanding about this subject. Anyone who seriously wants to understand the representation theory point of view on number theory and the Langlands program should find these lectures helpful.

This spring the Eilenberg lecturer will be Edward Frenkel, who will be lecturing on geometric Langlands and quantum field theory. In some sense he’ll be picking up where Gross left off. He was at Gross’s last lecture, and there was a ceremonial handing over of the chalk. Of course I’ve very much looking forward to these lectures, and I expect that there will again be video available.

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43 Responses to New For 2012

  1. pah says:

    my two cents: the banner graphic is way too big now.

  2. Peter Woit says:


    I kind of agree, but the header height doesn’t seem to be easily adjustable. For now I’m going to try just getting rid of the header. Should find a new one anyway…

  3. jorge says:

    My 2 cents:Congrats, great updates, but text font of this theme is not as easy to read as was before (arial/verdana)

  4. Bee says:

    Which banner graphic? I can’t see one (using Google Chrome, 1280×800). It looks pretty awful altogether with my browser. All the spacing is far too large. There is also no sidebar (should there be one?).

  5. Bee says:

    Ah, correction, there is a sidebar on the main page.

  6. Jim says:

    Clean and sleek, if spare.
    Uncluttered, yes. Sparse, perhaps.

    I shall miss your classic masthead graphic.
    This post What’s That at the Top of This Page? might not make sense without it.

  7. plm says:

    I like the new design, thank you. There is alot of empty space though, in many places, too much I find.

    Regarding ideas on ARep/QFT can you say a bit more -about yours and others’ if related, perhaps with references?


  8. cormac says:

    Sounds like a frightening teaching assignment! All of my own teaching is at undergrad level, thank God, plenty of time to work on other stuff. Though it must be great to have such a convergence of teaching and research.
    Re new design, I’m puzzled by the WordPress idea of putting all the links, headings on the homepage only – a lot of first-time readers may never make it to the homepage
    Best wishes for the NY, Cormac

  9. Joel Rice says:

    Just a tad surprised at not seeing a reference to Pertti Lounesto’s work on Spinors and Clifford Algebras, speaking of which, a long time ago somebody swore that the curvature of spacetime can actually be seen around Chevalley’s book on theTheory of spinors.

  10. nitpicker says:

    A tad puzzled why you say “Spin(2n) as a double cover of SO(2n)”. For example Spin(3) = SU(2) is the double cover of SO(3) is the classic example of spin angular momentum.

  11. Peter Woit says:

    I may yet try out some other wordpress themes for the blog. This one does seem to have way too much white-space, and no way to include a reasonably sized header graphic. We’ll see, don’t be surprised if you see some odd appearance tests over the next few days or so…

    Joel Rice, nitpicker,
    I don’t want to get into the intricacies of spinors here. In the course I’ll certainly discuss the relationship between SO(3) and Spin(3)=SU(2) and their reps, but for the general case of SO(n) and Spin(n), even and odd n behave somewhat differently. In the even case there’s a beautiful parallelism with the symplectic group which I want to discuss, so that’s the case I’ll work out in detail. If you take a look at the old lecture notes linked to, maybe you can see what I’m doing.

    The Lounesto book is nice, but this course isn’t aimed at physicists, so I’m not covering the Lorentz group, or anything about spin groups and spinors in the indefinite metric case, instead just sticking to the case of compact Lie groups and their finite-dim reps.

  12. Peter Woit says:

    Reverted to older default theme. The new one seemed to not be an improvement.

  13. Peter Woit says:


    The kind of automorphic representation/QFT relationship I have in mind was first discussed by Witten in his 1988 paper “Quantum field theory, Grassmanians and algebraic curves” (the QFTs in question are 2d CFTs). It’s something that clearly has inspired many of the people working on geometric Langlands (but it doesn’t have anything obviously to do with Witten’s work in recent years on geometric Langlands, higher-dim supersymmetric QFTs, and S-duality). Before trying to write more about this on the blog though, I’d first try and like to get something detailed down on paper. It’s a kind of long story, so requires much more than a blog entry…

  14. Low Math, Meekly Interacting says:

    I like spare more and more with every passing year. Perhaps internet-induced ADD has left me so impaired I’m incapable of resisting distractions, but there’s something almost comforting now about a white space filled with nothing but clean black text.

  15. SteveB says:

    FWIW. The old (now reverted back to) scheme constantly pops up an IE8 warning about a macro running that may be slowing down my browsing experience. I don’t notice any slow down however. The temporary large-white-space scheme did not have that. I do like having your links available on more than just the home page, which the old scheme accomodates.

  16. Peter Woit says:

    Thanks SteveB,

    The Windows machines I have access to run IE9, and that seems to work very well with the blog. If someone knows more about the IE8 problem and whether something can be done about it, let me know.

  17. Coin says:

    “there was a ceremonial handing over of the chalk”

    Frivolous question: Y’all still using chalkboards in New York? I thought everybody had moved to whiteboards by now.

  18. Peter Woit says:


    We’ve moved beyond whiteboards, to a much better technology: chalk. 20 years ago someone had a whiteboard installed in our lounge. 10 years later, one of the most popular decisions of the dept. chair was to have it ripped out and replaced with a chalkboard. At this point, they’ll have to pry the chalk from our cold, dead fingers….

  19. Peter, your comment about chalk put a smile on my face. When we moved into our new physics building down here, I specifically asked for a chalkboard in my office. A little dusty, but totally worth it.

  20. Chris W. says:

    SteveB and Peter,
    I am using IE8, and I see the slow-running script warning only after refreshing the page after initially accessing the site. I also get it on the search results pages, so the problem appears to originate in a page template.

    See this Microsoft Support KnowledgeBase article (ID# 175500), which offers an IE configuration fix (with the expected caveats).

  21. Chris W. says:

    PS: See this detailed discussion of the long-running script issue by web developer Nicholas Zakas.

  22. Richard says:

    If a web site consisting of plain text and a few diagrams needs to run scripts on the computers of every visitor who stops by to read that text, stealing valuable computrons from unsuspecting bystanders, then something is horribly wrong. It doesn’t matter if the script runs for a second or 20 milliseconds: anything more than zero indicates something is profoundly broken.

    Stop the insanity!

    PS Yes, comment previewing – a nice feature – is something that needs more than static HTML, for unfortunately historical reasons. But 99.99% of visitors aren’t commenting.

  23. Peter Woit says:

    I found a machine with an older IE, and think I identified the problem. It’s the WP-dTree plugin, which puts the archive listings in a nice hierarchical format. I turned off the feature that allows it to list all postings in a given month, and that seems to fix things. It looks like it was building a list of all 1000+ postings on the blog whenever the sidebar was loaded. Maybe there’s someway to make it more intelligent, and only generate listings of posts when you actually click on the month. Unless that gets figured out though, for now I’ll leave it as is, which just gives access to links allowing you to go to month-by-month archives, but no list of the postings in each month on the sidebar.

  24. Bernhard says:

    Off-topic. I read this article thinking would be of little interest more than a curiosity about Hawking´s birthday, but it managed to find time for hype:

    “The Large Hadron Collider at Cern, the European particle physics laboratory near Geneva, could do more than anything else to revolutionise scientists’ understanding of the universe, Hawking said. The machine could find “supersymmetric” particles, which are partners of the more familiar subatomic particles. Such a finding would be “strong evidence” for M-theory, a version of string theory that describes gravity and the other forces of nature in an 11-dimensional universe.”

  25. Peter Woit says:

    Thanks Bernhard,

    I saw that, was mainly impress by Hawking’s claim that the thing he spends the most time thinking about is women.

    If TeV scale SUSY would be “strong evidence” for M-theory, I guess that means no SUSY at the LHC will be strong evidence against M-theory, right?

  26. Giotis says:

    ” I guess that means no SUSY at the LHC will be strong evidence against M-theory, right?”

    Peter let me answer with a metaphor. God could perform a miracle and split the red sea. If the red sea splits in front of your eyes then this of course would be strong evidence for the existence of God. If the read sea does not split in front of your eyes that would be strong evidence against the existence of God? Of course not.

    This is just a metaphor, so please don’t reply that String theory is like a religion belief.

  27. Peter Woit says:

    OK Giotis,

    Bu you’re the one comparing our ability to test string theory with our ability to understand the ways of God, not me…

  28. Jeff M says:


    Sorry, but in a relevant version of the metaphor, it would have to be that god (or someone) told you that to prove it’s existence it would part the red sea. Then, if the red sea doesn’t part, it *is* evidence for the non-existence of god. You’re version of the metaphor doesn’t have a prediction in it, hence has no relation to the actual issue.


  29. swh bday says:

    Hawking birthday and LHC and “hype”. Once again, such comments have to be taken in context. It’s a celebration of Hawking’s 70th birthday, of course the press will be there, many eminent physicists (Lord Rees? Saul Permutter? What do *they* say about the multiverse/string theory?), many others. Hawking will naturally be asked about the LHC, and he can hardly say “it will be boring” or “it will find nothing of interest to me”. He will naturally say something with a spin of “optimism for great discoveries”. So what if it’s optimism about M-theory, whatever. If anyone here wants to get carried away with “hype”, that’s a reflection on you, not SWH.

    Wish SWH a happy birthday. He’s made it to 70. How many thought he would make it to 30?

  30. Mihai Pomarlan says:

    Uhm, what’s wrong with whiteboards? Is this another of those vynil vs. CD silly shibboleths?

  31. aa says:

    my whiteboard complaints:
    the whiteboard in my office has stuff on there for so long
    it requires scrubbing to get it off. i believe it was the correct markers,
    but we didn’t have the fluid and left it there and now it seems cemented on.

    the markers i find are always f-ng dried out and not working

    i hate the smell

  32. Jeff M says:

    Let me second aa on everything about whiteboards. Even as chair, I can’t get blackboards put in anywhere, only whiteboards are allowed. It was explained to me that this was because blackboard dust could damage computer equipment, which strikes me as ridiculous nowadays.

  33. Mihai Pomarlan says:

    Yeah well. All the blackboards I’ve encountered in (high)school and university had chalk caked into them, I hate the chalk dust, and trying to eke out the last few lines out of a crumpet of chalk is soo-oh delightful. I guess all of these complaints go both ways.

    What I didn’t know is that this is an actual issue at all (“save our blackboards” vs “whiteboard power”). A more relevant issue, at least in my background (engineering) was {white/black}board vs. projector. Any course that is heavy on math should, imo, rely heavily on {white/black}board, as seeing the flow of a proof being written in front of you is much better than just taking glances at slides. Especially when the presenter, who was an otherwise decent prof, had a monotone droney voice that discouraged wakefulness. Alas, progress marches on and where I studied, most courses that were not math pure and simple succumbed to projection.

  34. Peter Shor says:

    There were, at some point (shortly after the introduction of whiteboards) whiteboards that actually worked—they would be erasable for years and years, and you didn’t have to worry about markers drying on them and becoming permanent. We had some of those installed at Bell Labs. Unfortunately, the company that made them—I forget its name—seems to have been driven out of business long ago by companies who made cheaper whiteboards which don’t work.

  35. srp says:

    Blackboards are great when they’re completely pristine and you have a big piece of chalk. Once you start erasing, they become cloudy and messy. Whiteboards require some forethought or strong community norms to assure a supply of good markers, but they are so superior in terms of erasing (especially if you use purple) and allowing multiple colors that I have no nostalgia for the northeastern US preference for chalk.

  36. ateixeira says:

    ” I guess that means no SUSY at the LHC will be strong evidence against M-theory, right?”

    By sheer logic the answer is a resounding yes.

  37. swh bday says:

    ” I guess that means no SUSY at the LHC will be strong evidence against M-theory, right?”

    By sheer logic the answer is a resounding HB to SWH, regardless of what the blogosphere has to say about SUSY and the LHC.

  38. Attitude_Check says:

    A “fix” for a bad whiteboard is Pledge spray wax. Spray it on and wipe off. It will remove old marks and improve resistance to future permanence.

  39. Artie says:

    srp says:
    January 6, 2012 at 4:29 am

    Blackboards are great when they’re completely pristine and you have a big piece of chalk. Once you start erasing, they become cloudy and messy. Whiteboards require some forethought or strong community norms to assure a supply of good markers, but they are so superior in terms of erasing (especially if you use purple) and allowing multiple colors that I have no nostalgia for the northeastern US preference for chalk.

    The Germans have a good solution to the first problem you mention: every lecture room has a sink in it, and instead of an eraser you bring a squeegee with you. When the board is full, you wash it, and voila! it’s pristine again. It sounds absurd, but once you get used to it, it works rather well.

    My major objection to whiteboards is encapsulated in your third sentence: in my experience those “strong community norms” are almost impossible to enforce. A stick of chalk never spontaneously vanishes while you’re writing with it.

  40. Chris Oakley says:

    I cannot believe that such archaic communication devices are being promoted on a blog that purports to deal with cutting-edge physics. Surely the modern solution to the problem is having neural implants in the cerebral cortices of both the lecturer and the audience. These can communicate via an A-to-D converter and WiFi to the lecturer’s smartphone which uses Kinect to report his/her gestures, gestures which are then recorded and re-broadcast by an appropriate smartphone App (“iLecture”, let us call it). This scheme would have the additional advantage that one could integrate images from arXiv, or any other digital source, without further processing.

  41. Mark Bennet says:

    I think there is something about cognitive processing which is present when a lecturer has to make notes on a blackboard – even if they are in three different colours on three different boards just to draw attention to the three different notations – and there are lines between them which get displaced when the boards are shuffled – even so – and students have to make notes:

    … which is a very different learning experience to downloading the contents of a whiteboard onto your iPad – which is a route of engagement which does not necessarily pass through the brain.

    In other words there are some deep questions about the best use of technology which have not been thought through.

    But once upon a time paper did eventually take over from clay tablets as the note-taking medium of choice. So technological changes are possible, even in the 21st century.

  42. Nick M. says:

    If TeV scale SUSY would be “strong evidence” for M-theory, I guess that means no SUSY at the LHC will be strong evidence against M-theory, right?

    Unfortunately, no SUSY at the LHC does not necessarily mean no SUSY:

    See the recent January 6th, 2012 New Scientist article Higgs result means elegant universe is back in vogue.
    Oh well, the beat just goes on.

  43. pig with lipstick says:

    Physicists (or HEP theorists at least, but it’s really a much bigger set than that) have been searching for “elegance” and claiming “elegance” in their various theories/solutions since the birth of QM and probably much before that. So what else can one reasonably expect from a science magazine article?