A Note on QED with Magnetic Field and Chemical Potentia

Abstract

Using a generalized proper-time method, we obtain expressions for the fermion density and the QED effective Lagrangian for an external magnetic field at finite chemical potential. The effective Lagrangian and the density are here written in terms of elementary functions, summed over a finite number of filled Landau levels.Comment: 11 pages (postscript figure file appended at the end), FIAN/TD/94-01, G\"oteborg ITP 94-1