🚀 go-pugleaf

music@erich.triumf.ca (FRED W. BACH) writes:
>In article <gewIg2C00WBL01w4Qz@andrew.cmu.edu>, Paul Karol <pk03+@andrew.cmu.edu> writes...
>>A distinguished particle physicist not too long ago
>>seriously claimed that since the electron was the first fundamental
>>particle discovered, all of chemistry was beholden to particle physics. 
>   A bit stretched, but the discovery of the electron led to QED which
> led to a very much deeped understanding of solid-state physics which
> spawned semi-conductors which, in turn, spawned the computer, which
> makes this newsgroup possible.  Am I wrong?  I don't think so.

You're wrong.  As far as the theory of the electron goes, QED has had
no impact on solid-state physics whatsoever.  I have been a
solid-state physicist for 10 years, and I have never never seen or
heard a single reference to QED corrections to electron energy levels.
Even relativistic corrections to electron-energy levels (Darwin term)
are always ignored except for the actinides.  It is true that an
understanding of spin-orbit coupling is important to understanding
energy levels in semiconductors, but this is not QED!  Solid-state
physics doesn't really even use the full Dirac equation, except that
we are interested in the magnetic moment of the electron, which the
equation explains qualitatively.  The local-density theory which is
used to calculate the band structure of solids is based on the
Hartree-Fock theory and its elaborations by Kohn-Sham-Landau.
Hartree-Fock predated Dirac.

Having said all that, the theories of broken symmetry and elementary
excitations (Goldstone bosons) in solid-state physics have been heavily
influenced by particle theories.  Here solid-state is using the
_concepts_ of field theory, not the results!  My understanding is that
particle theories have been in turn influenced by solid-state theories
(e.g., non-perturbative field theories are greatly influenced by the
BCS theory of superconductivity).
-- 
Alison Chaiken 				alison@wsrcc.com
(510) 422-7129 [daytime] 		or chaiken@cmsgee.llnl.gov
Look if you like, but you will have to leap.