Electromagnetically Induced Entanglement

TL;DR

This paper introduces electromagnetically induced entanglement in a three-level atomic system, enabling nearly perfect entanglement between light fields through quantum coherence, with potential applications in quantum information processing.

Contribution

It demonstrates a new method to generate nondegenerate narrow-band entanglement using coherent laser fields in a Lambda-type atomic system.

Findings

High entanglement achieved with low decay rates and high pump intensity

Entanglement facilitated by quantum coherence between lower levels

Potential for broad applications in quantum information processing

Abstract

We present a novel quantum phenomenon named electromagnetically induced entanglement in the conventional Lambda-type three-level atomic system driven by a strong pump field and a relatively weak probe field. Nearly perfect entanglement between the pump and probe fields can be achieved with a low coherence decay rate between the two lower levels, high pump-field intensity, and large optical depth of the atomic ensemble. The physical origin is quantum coherence between the lower doublet produced by the pump and probe fields, similar to the well-known electromagnetically induced transparency. This method would greatly facilitate the generation of nondegenerate narrow-band continuous-variable entanglement between bright light beams by using only coherent laser fields, and may find potential and broad applications in realistic quantum information processing.