Quantum synchronization as a local signature of super- and subradiance

TL;DR

This paper explores the link between super- and subradiance and quantum synchronization, revealing that they share a common origin in coherence and occur simultaneously under pure dissipation, but are affected differently by noise.

Contribution

It analytically establishes the fundamental connection between quantum synchronization and subradiance in a minimal two-qubit system using the Liouville formalism.

Findings

Synchronization arises from coherence between ground and subradiant states

Synchronization and subradiance occur on the same timescale under pure dissipation

Dephasing noise breaks the reciprocity between synchronization and subradiance

Abstract

We study the relationship between the collective phenomena of super and subradiance and spontaneous synchronization of quantum systems. To this aim we revisit the case of two detuned qubits interacting through a pure dissipative bosonic environment, which contains the minimal ingredients for our analysis. By using the Liouville formalism, we are able to find analytically the ultimate connection between these phenomena. We find that dynamical synchronization is due to the presence of long standing coherence between the ground state of the system and the subradiant state. We finally show that, under pure dissipation, the emergence of spontaneous synchronization and of subradiant emission occur on the same time scale. This reciprocity is broken in the presence of dephasing noise.