Non-Fermi liquid behavior due to U(1)U(1) gauge field in two dimensions

We study the damping rate of massless Dirac fermions due to the U(1)U(1) gauge field in (2+1)(2+1)-dimensional quantum electrodynamics. In the absence of a Maxwell term for the gauge field, the fermion damping rate ImΣ(ω,T) is found to diverge in both perturbative and self-consistent results. In the presence of a Maxwell term, there is still divergence in the perturbative results for ImΣ(ω,T). Once the Maxwell term is included into the self-consistent equations for fermion self-energy and vacuum polarization functions, the fermion damping rate is free of divergence and exhibits non-Fermi liquid behavior: ImΣ(ω,T)∝max(ω,T).