Theory of collective Raman scattering from a Bose-Einstein condensate

TL;DR

This paper develops a quantum theoretical framework for superradiant Raman scattering in Bose-Einstein condensates, explaining how collective atomic recoil leads to matter wave amplification and entangled atom-photon pairs.

Contribution

It introduces a quantum model for superradiant Raman scattering in BECs, including mechanisms for matter wave amplification and entanglement generation.

Findings

Raman amplification of matter waves due to collective atomic recoil

Generation of entangled atom-photon pairs in a closed two-level system

Backward recoiling atoms can be produced when initial states are prepared accordingly

Abstract

Recent experiments have demonstrated superradiant Raman scattering from a Bose-Einstein condensate driven by a single off-resonant laser beam. We present a quantum theory describing this phenomenon, showing Raman amplification of matter wave due to collective atomic recoil from 3-level atoms in a $\Lambda$-configuration. When atoms are initially in a single lower internal state, a closed two-level system is realized between atoms with different internal states, and entangled atom-photon pairs can be generated. When atoms are initially prepared in both the lower internal states, a fraction of atoms recoiling in the backward direction can be generated.