Scrambling and operator entanglement in local non-Hermitian quantum systems

Abstract

In weakly monitored quantum systems, traditional diagnostics of operator spreading such as out-of-time-ordered-correlators and Lieb-Robinson bounds can break down, as entanglement can spread at seemingly unbounded velocity. This has the adverse effect of making integrable and chaotic quantum dynamics appear identical. However, as the authors show here, the humble quantity of global operator entanglement remains a reliable metric of chaoticity in these systems. They elucidate this by studying entanglement phase transitions in a local, non-Hermitian transverse-field Ising model under the lens of operator and quenched entanglement dynamics.

Topics & Concepts