Subject: Minimal coupling

From: SAUE Trond <[email-masked]>
Date: Tue, 09 Oct 2001 17:27:47 +0200

External fields are introduced into the Hamiltonian by the substitutions

	p -->  p-qA  ;  H -> H +q(phi)

This is referred to as minimal coupling or, more formally, as the
principle
of minimal electromagnetic coupling and ensures gauge invariance of the 
resulting Hamiltonian. My questions is: Who introduced this principle ?
I have been looking in a number of standard books ranging from 
classical electromagnetic theory to QED without finding such historical
references and a general discussion of the principle.
   All the best,
      Trond Saue
-- 
Trond SAUE                                (DIRAC:
http://dirac.chem.sdu.dk/)
Laboratoire de Chimie Quantique et Modélisation Moléculaire
Université Louis Pasteur ; 4, rue Blaise Pascal ; F-67000 STRASBOURG
tél: 03 90 24 13 01   fax: 03 90 24 15 89   email:
[email-masked]