Induced Magnetic Field in a Finite Fermion Density Maxwell QED$_{2+1}$

Abstract

We are studying finite fermion density states in Maxwell QED$_{2+1}$ with external magnetic field. It is shown that at any fermion density the energy of some magnetized states may be less than that of the state with the same density, but no magnetic field. Magnetized states are described by the effective Maxwell-Chern-Simons QED$_{2+1}$ Lagrangian with gauge field mass proportional to the number of filled Landau levels.