A supercomputer study of strongly coupled QED

Abstract

We study non-compact QED with light dynamical fermions using hybrid algorithms for N = 2 and 4 species of light fermion. We present evidence from measurements of the chiral condensate on 6 4, 8 4 and 10 4 lattices that the theory has an interacting ultraviolet stable fixed point. Simulations on 2×8 3, 4×8 3, 6×12 2 and 8×16 3 lattices indicate that the theories have nontrivial temperature dependence and their dynamics generates a large correlation length. Simulations of the π, ϱ, A 1, σ mesons and the photon and fermion propagators are done on 6 3×12 lattices. The level ordering of the mesons is m π < m σ < m ϱ < m A 1 . The photon mass, inferred from its propagator in the Landau gauge, is zero.