Manipulating mesoscopic multipartite entanglement with atom-light interfaces

TL;DR

This paper explores how atom-light interfaces can be used to generate, manipulate, and detect genuine multipartite entanglement among mesoscopic atomic ensembles, extending previous bipartite entanglement methods.

Contribution

It demonstrates the feasibility of controlling multipartite entanglement in atomic ensembles using multiple light pulses, including reversing entanglement under realistic conditions.

Findings

Second light pulse can modify or reverse entanglement

Extension of bipartite entanglement to multipartite systems

Realistic conditions enable control over entanglement

Abstract

Entanglement between two macroscopic atomic ensembles induced by measurement on an ancillary light system has proven to be a powerful method for engineering quantum memories and quantum state transfer. Here we investigate the feasibility of such methods for generation, manipulation and detection of genuine multipartite entanglement between mesoscopic atomic ensembles. Our results extend in a non trivial way the EPR entanglement between two macroscopic gas samples reported experimentally in [B. Julsgaard, A. Kozhekin, and E. Polzik, Nature {\bf 413}, 400 (2001)]. We find that under realistic conditions, a second orthogonal light pulse interacting with the atomic samples, can modify and even reverse the entangling action of the first one leaving the samples in a separable state.