I’ve been finding recently that an increasing serious problems with blogs is that there are too many good ones with material worth reading. I’ve learned quite a lot recently from many well-informed blog postings, but the sheer number of these makes it hard to find the time for other things one should be doing.
I’ll violate my usual rule of sticking to math and physics and report that my brother Steve is joining me in the family blogging business by being involved as Publisher in a new venture that just launched this week called Xconomy. Basically it’s a blog based up in Cambridge, with offices in Kendall Square, devoted to news about what they call the “exponential economy”, that part of the economy responsible for what is perhaps too optimistically described as exponential growth in certain areas. They’re focusing on events and news relevant to new technology, especially bio-technology, businesses in the Boston area. For some interesting blog postings by their CEO Bob Buderi about what it’s like to start up this sort of business, see here and here. For a nice posting about Doc Edgerton, see here.
Back to physics and math, over at Backreaction there’s an excellent posting on the GZK cutoff and high energy cosmic ray experiments, and a report from Loops 07 sent in via Blackberry by Sabine Hossenfelder.
An American Physics Student in England tells about a recent conference on Heavy Flavour Physics, giving a very nice overview of what is going on in that field.
The latest This Week’s Finds in Mathematical Physics from John Baez is out (available here, blog entry and comments here). It’s a wonderful description of the various mathematical patterns that the standard model particles fit into. Most well known is what happens in SU(5) and SO(10) GUTs, where one can fit the fermion quantum numbers into something that can equivalently be described as the spinor representation in d=10, or the exterior algebra $\Lambda ^* (\mathbf C ^5)$. John goes on to explain various possible connections to the exceptional groups, including a recent idea from Garrett Lisi about how to use E8 to get three generations.
The blog entry comments discuss two recent papers by Chamseddine and Connes about their non-commutative algebra approach to this question of mathematically characterizing the SM degrees of freedom. The papers are on the arXiv, entitled A Dress for SM the Beggar, and Why the Standard Model. Because of these papers and Witten’s recent one, John seems to be getting a bit more optimistic about physics, writing “I get the feeling that theoretical physics may not be quite so stagnant after all!”
All sorts of interesting stuff at the Secret Blogging Seminar, including yet more about Connes: a “review” by A. J. Tolland of the first quarter of the new book by Connes and Marcolli (available here), which A. J. claims has the title Noncommutative Geometry, Quantum Fields, Kitchen Sinks and Motives. Like the earlier fat book on non-commutative geometry by Connes, it’s an amazing document, ranging widely over physics and mathematics, covering ground from QFT to the Riemann hypothesis, at a level varying from expository sections on well-known subjects to more speculative research-level discussions. I’ve just started looking at it, may bring along a copy for summer vacation reading when I head up to a lake in New Hampshire tomorrow.
Other interesting things at the same blog include reports (here and here) from Ben Webster about talks by Sergei Gukov on categorification and gauge theory (about which he has a new expository paper here), as well as about an earlier talk by Gukov on Arithmetic Topology and Gauge Theory.
Also worth reading are posts from Ben Webster about centers of blocks of category O, various comment section discussions with David Ben-Zvi at both this blog and the n-category cafe, and a series of postings by David Speyer about quadratic reciprocity and geometric class field theory (I’m running out of energy to provide links…).
From Ben-Zvi (who could run a really great blog if he chose to…) there are notes from the recent conference at Northwestern on non-commutative geometry. These include an intriguing lecture by Beilinson, as well as lectures by Nadler and Ben-Zvi himself about their recent work which connects geometric Langlands with questions about more conventional representation theory using striking ideas about how to handle loop spaces. They have a recent paper about this, which has been very high on my list of things I wish I understood better ever since David gave an inspiring talk about this here a couple months ago.
Finally, one more thing definitely worth looking at in light of Witten’s new work: an expository and historical article by Jim Lepowsky about the story of the relation of vertex operator algebras and the monster group. He explains what is so remarkable about the specific vertex operator algebra that Witten is connecting to 3d gravity on AdS, including the ways in which it is conjecturally uniquely the “smallest” such structure in a specific sense.