Aleksey Lunkin, Landau Institute Moscow
We study the out-of-time-order correlation function (OTOC) in a lattice extension of the Sachdev-Ye-Kitaev (SYK) model with quadratic perturbations. The results obtained are valid for arbitrary time
scales, both shorter and longer than the Ehrenfest time. We demonstrate that the region of well-developed chaos is separated from the weakly chaotic region by the “front region”, which moves ballistically across the lattice. The front velocity is calculated for various system’s parameters, for the first time for SYK-like models.