Characterization of quantum chaos by two-point correlation functions.

Gharibyan, Hrant; Hanada, Masanori; Swingle, Brian; Tezuka, Masaki · Phys Rev E · 2020

basic_science · Level V

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Abstract

We propose a characterization of quantum many-body chaos: given a collection of simple operators, the set of all possible pair correlations between these operators can be organized into a matrix with a random-matrix-like spectrum. This approach is particularly useful for locally interacting systems, which do not generically show exponential Lyapunov growth of out-of-time-ordered correlators. We demonstrate the validity of this characterization by numerically studying the Sachdev-Ye-Kitaev model and a one-dimensional spin chain with random magnetic field (XXZ model).