Beyond pure state entanglement for atomic ensembles

Abstract

We analyze multipartite entanglement between atomic ensembles within quantum matter-light interfaces. In our proposal, a polarized light beam crosses sequentially several polarized atomic ensembles impinging on each of them at a given angle α i . These angles are crucial parameters for shaping the entanglement since they are directly connected to the appropriate combinations of the collective atomic spins that are squeezed. We exploit such a scheme to go beyond the pure state paradigm proposing realistic experimental settings to address multipartite mixed state entanglement in continuous variables.

Composite-cluster states and alternative architectures for one-way quantum computation

“…CV cluster states can be built, not only from optical modes but also from ensembles of polarized atoms where each ensemble is a different CV mode [20][21][22][23]. The ensembles are entangled by performing interactions with off-resonant linearly polarized light, which, on the classical level, performs a Faraday rotation.…”