Chaos, entanglement and decoherence in the quantum kicked top

TL;DR

This paper investigates how chaos influences entanglement and decoherence in a quantum kicked top system, demonstrating experimentally accessible signatures of chaos in entanglement dynamics even with decoherence effects.

Contribution

It introduces a method to measure entanglement dynamics in a quantum kicked top and explores how chaos signatures persist under realistic decoherence conditions.

Findings

Chaos signatures appear in entanglement dynamics for accessible parameters.

Entanglement evolution depends on initial state's support on regular or chaotic eigenstates.

Chaos influences the decoherence rate, affecting system stability.

Abstract

We analyze the interplay of chaos, entanglement and decoherence in a system of qubits whose collective behaviour is that of a quantum kicked top. The dynamical entanglement between a single qubit and the rest can be calculated from the mean of the collective spin operators. This allows the possibility of efficiently measuring entanglement dynamics in an experimental setting. We consider a deeply quantum regime and show that signatures of chaos are present in the dynamical entanglement for parameters accessible in an experiment that we propose using cold atoms. The evolution of the entanglement depends on the support of the initial state on regular versus chaotic Floquet eigenstates, whose phase-space distributions are concentrated on the corresponding regular or chaotic eigenstructures. We include the effect of decoherence via a realistic model and show that the signatures of chaos in the entanglement dynamics persist in the presence of decoherence. In addition, the classical chaos affects the decoherence rate itself.