Physical Review Research (Dec 2020)
Fast scrambling without appealing to holographic duality
Abstract
Motivated by the question of whether all fast scramblers are holographically dual to quantum gravity, we study the dynamics of a nonintegrable spin chain model composed of two ingredients: a nearest neighbor Ising coupling, and an infinite range XX interaction. Unlike other fast scrambling many-body systems, this model is not known to be dual to a black hole. We quantify the spreading of quantum information using an out-of time-ordered correlator (OTOC), and demonstrate that our model exhibits fast scrambling for a wide parameter regime. Simulation of its quench dynamics finds that the rapid decline of the OTOC is accompanied by a fast growth of the entanglement entropy, as well as a swift change in the magnetization. Finally, potential realizations of our model are proposed in current experimental setups. Our work establishes a promising route to create fast scramblers.