This looks fascinating. Michael Williams, over at kuro5hin.org:

"If you’ve played Sim City you’ve wrestled with one of the problems faced by supercomputer designers. Unfortunately there’s no GameFAQs.com for the technical staff at Japan’s Earth Simulator or Srinidhi Varadarajan and colleagues at Virginia Tech. True enough, they won’t have to deal with rising crime or Godzilla but, as hinted at in a recent paper in Journal of Physics A, the physical layout of a massively parallel supercomputer is fundamentally the same problem as minimizing the time commuters spent stuck in traffic jams. Cities and people are just too complicated for a complete and rigorous mathematical treatment of commuter behaviour. However, in spite of the simplifications made in What is the optimal shape of a city? by Carl Bender et al, their results provide food for thought for supercomputer designers and Sim Mayors. This article contains a summary of those results, some background on the techniques they used, and a critical assessment of the extent to which they can be applied"

Michael Williams suggests that the model contained in the paper above is a little reductionistic (Bender et al’s thesis contains this tantalising quote: "In the language of continuum mechanics, the shape of the optimal city is that taken by a blob of incompressible fluid composed of molecules whose pairwise interactions are described by an attractive potential proportional to the Manhattan distance between the particles." Got that?!). None the less, the paper describes another interesting analytical method of looking at one aspect of the city, with Michael’s fabulously link-packed article describing both the advantages and disadvantages of such an approach.

kuro5hin: Can you use theoretical physics to design a city or a supercomputer?