Spin Squeezing, Negative Correlations, and Concurrence in the Quantum Kicked Top Model

TL;DR

This paper investigates the relationship between spin squeezing, negative correlations, and entanglement in the quantum kicked top model, revealing how quantum chaos influences these quantum correlations and their dynamics.

Contribution

It proves the equivalence of spin squeezing and negative correlations in symmetric Dicke states and analyzes how quantum chaos affects spin squeezing and entanglement dynamics.

Findings

Spin squeezing and negative correlations are equivalent in symmetric Dicke states.

Quantum chaos significantly influences the direction of maximal spin squeezing.

Entanglement exhibits sudden death and birth, depending on the dynamical regime.

Abstract

We study spin squeezing, negative correlations, and concurrence in the quantum kicked top model. We prove that the spin squeezing and negative correlations are equivalent for spin systems with only symmetric Dicke states populated. We numerically analyze spin squeezing parameters and concurrence in this model, and find that the maximal spin squeezing direction, which refers to the minimal pairwise correlation direction, is strongly influenced by quantum chaos. Entanglement (spin squeezing) sudden death and sudden birth occur alternatively for the periodic and quasi-periodic cases, while only entanglement (spin squeezing) sudden death is found for the chaotic case.