Quenches and (pre)thermalization in a mixed Sachdev-Ye-Kitaev model

We study the nonequilibrium quench dynamics of a mixed Sachdev-Ye-Kitaev model, with competing two-body random interactions leading to maximally chaotic non-Fermi liquid and single body term which dominates at low temperatures leads Fermi behavior. For different protocols, including sudden switching interaction double we solve large $N$ real-time Dyson equation on Keldysh contour compute Green's functions from obtain effective temperature relaxation rates. show that model thermalizes finite equilibrium depending value parameters, can be below or above Fermi-liquid crossover scale, then accessed through dynamics. identify protocols for heating slow down significantly---an effect interpret as signature prethermalization.