🚀 go-pugleaf

In article <1992Nov7.034453.2080@murdoch.acc.Virginia.EDU> crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass) writes:
>In article <1992Nov6.233219.15750@galois.mit.edu> jbaez@riesz.mit.edu (John C. Baez) writes:
>
>>Yes, here there seems to be a very nice interplay.  It's one of the few
>>things that keeps physicists talking to each other, the mathematical
>>analogies between condensed matter physics and field theory.  All sorts
>>of tricks, like the ones you mention and also renormalization group
>>methods, solitons and instantons, etc., show up in both subjects.
>>Here's to the unity of nature!
>
>     I enjoy a bit of good interplay, now and again, myself.  But do you
>     not think to a certain extent, that this is the result of the existence of
>     the most fashionable tool in our toolbox?

The fashionableness of a theory plays a big role in why people look all over 
for examples of phenomena that fit the theory - or not, as the case may be.
But the fact that so many tools apply to both solid state physics and quantum
field theory is due to the fact that their mathematical structures are closely
related, being both quantum theories of field-like phenomena.   When you find
that quantum fields can form solitons, you can easily find solid state (or 
condensed matter!) systems that display solitons.  In solid state you have
quite a bit of choice in terms of finding systems that have roughly some
Lagrangian or other, so you can really test your mathematical notions to
some extent.  (Typically, of course, the real condensed matter system is
more complicated than the Lagrangian you guessed for it, so these "tests"
are always suspect.)