🚀 go-pugleaf

In article <1992Dec21.063339.27448@nuscc.nus.sg> matmcinn@nuscc.nus.sg (Brett McInnes) writes:
>baez@guitar.ucr.edu (john baez) writes:
>[interesting stuff deleted]:                                              
>:    
>Can anyone								  
> [a] give me an example of a theory that is *not* diffeomorphism invariant
> [b] explain to me whether "real" physicists "really" care about
>Chern-Simonsology [meaning: do they actually have a concrete use for it,
>or is it something that people do while waiting for the next theory of
>everything to come along?]					          
   At least a few physicists studying the fractional quantum Hall effect 
believe Chern-Simons field theories are relevant to the real world.
E.g., A. Lopez and E. Fradkin, Phys Rev B 44, 5246 (1991) [chosen because
it's a local product].  Actually there are several flavors of Chern-Simons
theories for the FQHE floating around, all of which (one hopes) would
yield the same results could they be treated exactly.
> ps I have no objection either to mathematical physics with no obvious
>applications, or to things like conformal field theory that are
>interesting but of no real use. Nor am I of the school who say say "so
>what" when informed of the relationship between knot theory and QFT. I ask
>merely for information.
   Hey, who says conformal field theory is of no real use???  Down here
in low-energy physics it has been fruitful in problems such as
quantum spin chains, multichannel Kondo systems, and 2D finite-temperature
critical phenomena (including random systems).

Happy Holidays,
Marty Gelfand  marty@amaterasu.physics.uiuc.edu