1st Quantum corrections to the classical partition-function for a nonrelativistic electrodynamic system

Abstract

The classical partition function for a system in thermodynamical equilibrium formed by N identical non-relativistic particles interacting through Coulomb potentials and with the dynamical dectromagnetic field is studied. It is proved that the dynamical or transverse EM degrees of freedom decouple from the particle ones. It is also shown that this decoupling does to take place in the quantum mechanical partition function. The leading quantum corrections to the classical partition function are explicitly given. Such corrections are shown, to be determined by instantaneous dipole-dipole coulombic interactions and by self-energy effects, and to receive no contribution from the interaction among different particles mediated by the dynamical EM field.