Thermalization of randomly coupled SYK models

Abstract We investigate the thermalization of Sachdev–Ye–Kitaev (SYK) models coupled via random interactions following quenches from perspective entanglement. Previous studies have shown that when a system two SYK by two-body terms is quenched thermofield double state with sufficiently low effective temperature, Rényi entropies do not saturate to expected thermal values in large- N limit. Using numerical methods, we first show pair can thermalize, if high and hence exhibit state-dependent thermalization. In contrast, single-body appear always thermalize. provide evidence subthermal behavior former likely artifact repeating quench for finite finding saturation value entropy extrapolates → ∞ Finally, as finer grained measure thermalization, compute late-time spectral form factor reduced density matrix after quench. While single dot exhibits perfect agreement theory, both quadratically quartically slight deviations.