Many-body quantum chaos in a non-Fermi liquid model with spatially random interactions.

A description of strange metal states is crucial for understanding strong electron correlations in important materials such as high T_c superconductors and twisted bilayer graphene. One of the viable theories for strange metals is a two-dimensional model of critical Fermi surfaces in the presence of spatially random interactions. The model displays T-linear resistivity at temperatures T→0, which is the defining feature of strange metal behavior, along with other experimentally observed features. In addition to transport properties, it is also important to understand relaxational and thermalization phenomena in strange metals, which shed light on their non-equilibrium properties. To describe a portion of these, we compute out-of-time ordered correlation functions (OTOCs) of fermion operators. We show that the presence of a residual resistivity, often seen in experiments, induces an emergent integrability at low energies, slowing down the growth rate of OTOCs from the maximum possible value of 2πT as T→0, despite the linear T-dependence of the resistivity and the seeming absence of quasiparticles.