Temperature Expansions for Magnetic Systems

Abstract

We derive finite temperature expansions for relativistic fermion systems in the presence of background magnetic fields, and with nonzero chemical potential. We use the imaginary-time formalism for the finite temperature effects, the proper-time method for the background field effects, and zeta function regularization for developing the expansions. We emphasize the essential difference between even and odd dimensions, focusing on $2+1$ and $3+1$ dimensions. We concentrate on the high temperature limit, but we also discuss the $T=0$ limit with nonzero chemical potential.