The operator Lévy flight: light cones in chaotic long-range interacting systems

Abstract: We argue that chaotic power-law interacting systems have emergent limits on information propagation, analogous to relativistic light cones, which depend on the spatial dimension $d$ and the exponent $\alpha$ governing the decay of interactions. Using the dephasing nature of quantum chaos, we map the problem to a stochastic model with a known phase diagram. A linear light cone results for $\alpha \ge d+1/2$. We also provide a L\'evy flight (long-range random walk) interpretation of the results and show consistent numerical data for 1d long-range spin models with 200 sites.