In this letter we study (2+1)-dimensional QED. The first part contains the computation of the flavor symmetry-breaking condensate and its relation to the trace of the energy-momentum tensor, while the second part is concerned with the computation of the effective action allowing for non-constant static external magnetic fields. We do not find that space derivatives in the magnetic field lower the energy of the ground state as compared to a constant field configuration.
@article{arxiv.hep-th/9609197,
title = {Flavor Condensate and Vacuum (In-)Stability in QED_(2+1)},
author = {Walter Dittrich and Holger Gies},
journal= {arXiv preprint arXiv:hep-th/9609197},
year = {2009}
}