Mutual information as an order parameter for quantum synchronization

TL;DR

This paper proposes mutual information as a universal order parameter to detect synchronization across classical and quantum systems, demonstrated through coupled oscillators and qubits in optical cavities.

Contribution

It introduces mutual information as a novel, system-independent measure for quantum synchronization, validated across diverse physical models.

Findings

Mutual information effectively indicates synchronization phases.

Applicable to both classical and quantum regimes.

Works for coupled oscillators and qubits in optical cavities.

Abstract

Spontaneous synchronization is a fundamental phenomenon, important in many theoretical studies and applications. Recently this effect has been analyzed and observed in a number of physical systems close to the quantum mechanical regime. In this work we propose the mutual information as a useful order parameter which can capture the emergence of synchronization in very different contexts, ranging from semi-classical to intrinsically quantum mechanical systems. Specifically we first study the synchronization of two coupled Van der Pol oscillators in both classical and quantum regimes and later we consider the synchronization of two qubits inside two coupled optical cavities. In all these contexts, we find that mutual information can be used as an appropriate figure of merit for determining the synchronization phases, independently of the specific details of the system.