Operator scrambling and quantum chaos

Understand

Operator scrambling is a crucial ingredient of quantum chaos.

• Specifically, in the quantum chaotic system, a simple operator can become increasingly complicated under unitary time evolution.
• This can be diagnosed by various measures such as square of the commutator (out-of-time-ordered correlator), operator entanglement entropy etc.
• In this paper, we discuss operator scrambling in three representative models: a chaotic spin-$1/2$ chain with spatially local interactions, a 2-local spin model and the quantum linear map.