Generating long-lived entangled states with free-space collective spontaneous emission

TL;DR

This paper demonstrates how collective spontaneous emission in a cloud of atoms can generate long-lived, entangled states, with entanglement duration increasing with interaction strength, independent of geometry.

Contribution

It reveals that superradiance and subradiance can produce long-lived entangled states in atomic clouds without geometric constraints or interaction thresholds.

Findings

Long-lived entangled states emerge from cooperative spontaneous emission.

Stronger interactions result in longer entanglement lifetimes.

Entanglement occurs independently of the atoms' geometrical arrangement.

Abstract

Considering the paradigmatic case of a cloud of two-level atoms interacting through common vacuum modes, we show how cooperative spontaneous emission, which is at the origin of superradiance, leads the system to long-lived entangled states at late times. These subradiant modes are characterized by an entanglement between all particles, independently of their geometrical configuration. While there is no threshold on the interaction strength necessary to entangle all particles, stronger interactions lead to longer-lived entanglement.