  Quantum electrodynamics (QED) is a cornerstone of particle physics and also
finds diverse applications in condensed matter systems. Despite its
significance, the dynamics of quantum electrodynamics under a quantum quench
remains inadequately explored. In this paper, we investigate the nonequilibrium
regime of quantum electrodynamics following a global quantum quench.
Specifically, a massive Dirac fermion is quenched to a gapless state with an
interaction with gauge bosons. In stark contrast to equilibrium
(3+1)-dimensional QED with gapless Dirac fermions, where the coupling is
marginally irrelevant, we identify a nonequilibrium fixed point characterized
by nonFermi liquid behavior. Notably, the anomalous dimension at this fixed
point varies with the initial quench parameter, suggesting an interesting
quantum memory effect in a strongly interacting system. Additionally, we
propose distinctive experimental signatures for nonequilibrium quantum
electrodynamics.
