Ruiz Ruiz, FernandoÁlvarez Estrada, Ramón F.2023-06-212023-06-2119860015-820810.1002/prop.19860341103https://hdl.handle.net/20.500.14352/64928Copyright © 1999-2014 John Wiley & Sons, Inc. All Rights Reserved. The partial financial support given by Comisión Asesora de Investigación Cientifica y Técnica. Spain, is acknowledged. One of us (F.R.R.) whishes to express his gratitude to the Department of Theoretical Physics of the University of Zaragoza for hospitality.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.spajournal articlehttp://dx.doi.org/10.1002/prop.19860341103http://onlinelibrary.wiley.comopen access53PhysicsMultidisciplinaryFísica (Física)22 Física