Scott Aaronson has posted an extremely funny parable on his weblog about physicists and impossibility proofs.
Call for papers
I’m flying to Seattle in a few hours, and it is a ~two hour flight. Anyone have any good ideas for a good paper to print out from the Arxiv (or elsewhere) to read during? Anything to keep me absorbed during that tedium? I fly back on Monday, so I suppose it could be a 4 hour paper 
Plus magazine #39
The latest issue of Plus Magazine is now out, with articles about Godel and NASA.
Baez Week 234
Week 234 of John Baez’ This Week in Mathematical Physics is up. Most of this week’s edition is about the relationship of mathematics and music, but he does touch on a topic we’ve discussed before: weird orbits in classical mechanics. Cris Moore and Michael Nauenberg have found many new and strange solutions to the n-body problem and have provided movies (animated GIFs). The most amazing one is 21 bodies all moving along the same figure eight orbit.
Wanted: game theorists
The University of Liverpool (UK) has a vacancy for a post-doc researcher and for a PhD student, both in automated mechanism design. The expertise we are looking for includes game theory, mechanism design and auction theory, mathematical economics, and computational versions of same. These posts are part of a major UK research project on market-based control of complex computational systems.
Eveything old is new again.
I don’t really have a good sense of how much crossover there is between the math blogosphere (such as there is one) and the physics blogosphere (hoo baby!). More specifically, I know that there is some crossover from the physics people to this site, but I am unclear on the other direction. Walt tells me that we have the most read math blog \exists, so I thought I would direct our ten readers to the brouhaha that has managed to coalesce around one of our crossovers, Peter Woit. We link to his blog, so there really is no point to this post, other than for me to comment, that it reminds me of Einstein’s comment “What is all the sturm and drang among the mathematicians?” in reference to the big dust-up brought on by Brouwer’s Intuitionist program, only this time the roles are reversed. Since I have no investment in string theory being correct as far as interpretations go, and only really look at it as some cool mathematics (and get to say “not my area”), I get to embrace the shadenfreud that exists at the core of my being and exhort: FIGHT!, FIGHT!
Shalizi on Everything
I’ve been poking around Cosma Shalizi‘s website recently. He has a little bit of everything: a weblog, a set of book reviews he’s written, and a large collection of mini-essays (which he calls “notebooks”). The bulk of the material revolves around the related subjects of probability, machine learning, and dynamical systems (all with a strong physics flavor), but he touches on many other topics.
Ellis on Large Deviations
What triggered my current plunge into thermodynamics was this miniature book review by Cosma Shalizi of Richard S. Ellis’ Entropy, Large Deviations, and Statistical Mechanics:
In addition to being an excellent exposition of the rigorous theory of large deviations (especially for physicists, naturally!), this is also one of the most conceptually satisfying approaches to the foundations of statistical mechanics. In particular, it makes good probabilistic sense of the method of maximum entropy, without invoking weird sub-Bayesian ideas about statistical inference. (Namely, maximum Gibbs-Shannon entropy drops out as an approximate consequence of large deviations theory, when considering a small part of a large system, becoming exact only in the thermodynamic limit. As Ellis says, the core of this idea goes back to Boltzmann.)
I find the idea of statistical mechanics fascinating: that to describe the behavior of truly gigantic numbers of particles, all we need are a few bulk properties such as temperature and pressure. And to find out that it has a simple mathematical description in terms of probability theory, that’s the kind of thing that makes me want to know more.
Tragically, my library doesn’t have Ellis’ book, but I was able to track down home page, which has an extensive list of publications, many of which are available on-line. Two in particular give an overview of the relationship between statistical mechanics and large deviations:
- The Theory of Large Deviations: from Boltzmann’s 1877 calculation to equilibrium macrostates in 2D turbulence
- An Overview of the Theory of Large Deviations and Applications to Statistical Mechanics
Cosma also has a quick intro to large deviations. (In a rare lapse, Wikipedia has almost nothing. All that’s there is a pathetic little stub that I just created to fix what was there before, which was an incorrect redirect to extreme value theory.)
Thermodynamics
Something I’d always meant to do is learn something about thermodynamics. I’ve tried several times, but each time I get bogged down in the details of heat engines. This time, I found some very nice lecture notes by Nino Boccara. They provide an overview abstracted enough from the physical details to be informative to a mathematical audience. They take entropy as a primitive concept rather than deriving it from properties of heat engines.
(I’ve been trying to find other introductions from the same point of view of Boccara, but with more detail. I haven’t had any luck. Rather than sticking closely to ideal gases, Boccara takes a general view of the formalism, one that does not (in principle) even require energy as one of the state variables. His approach to statistical mechanics is related to the maximum entropy approach of E. T. Jaynes.)
All your base are belong to us.
Could someone with accurate knowledge of the state of the verification of Perelman’s proof of the Poincare conjecture comment on this article?
I would like to know if it is complete crap or not.