Quantum electrodynamics under a quench

Quantum electrodynamics (QED) is a cornerstone of particle physics and also finds diverse applications in condensed matter systems. However, the dynamics of quantum electrodynamics under a quantum quench remain inadequately explored. We investigate the nonequilibrium regime of quantum electrodynamics following a global quantum quench on the mass of the fermion. 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 non-Fermi 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.