SYK model, chaos and conserved charge

Abstract

A bstract We study the SYK model with complex fermions, in the presence of an all-to-all q -body interaction, with a non-vanishing chemical potential. We find that, in the large q limit, this model can be solved exactly and the corresponding Lyapunov exponent can be obtained semi-analytically. The resulting Lyapunov exponent is a sensitive function of the chemical potential μ . Even when the coupling J , which corresponds to the disorder averaged values of the all to all fermion interaction, is large, values of μ which are exponentially small compared to J lead to suppression of the Lyapunov exponent.