Accelerated gap collapse in a Slater antiferromagnet

We study the melting of long-range antiferromagnetic order in Hubbard model after an interaction quench, using non-equilibrium dynamical mean-field theory. From previous studies, system is known to quickly relax into a prethermal symmetry-broken state. Using convergent truncation memory integrals Kadanoff Baym equations, we unravel subsequent relaxation dynamics this state over several orders magnitude time. At long times, can be characterized by single slow variable which related conduction band population. The does not follow paradigmatic steady pre-thermal states: It highly nonlinear, with pronounced speedup once gap falls below certain value. This behavior indicates that non-thermal self-stabilized on some timescale. reproduced simple Fermi's golden rule estimate for evolution