Magnetic Catalysis of Chiral Symmetry Breaking in QED at Finite Temperature
Abstract
The catalysis of chiral symmetry breaking by a magnetic field in the massless weak-coupling phase of QED is studied. The dynamical mass of a fermion (energy gap in the fermion spectrum) is shown to depend essentially nonanalytically on the renormalized coupling constant
α
in a strong magnetic field. The temperature of the symmetry restoration is calculated analytically as
T
c
≈
m
dyn
, where
m
dyn
is the dynamical mass of a fermion at zero temperature.