Generation of pulsed bipartite entanglement using four-wave mixing

TL;DR

This paper demonstrates the generation of pulsed bipartite entangled twin beams in hot atomic vapor using four-wave mixing, achieving significant noise reduction and EPR inequality violation, suitable for quantum memory applications.

Contribution

It introduces a method to produce pulsed entangled beams compatible with quantum memories using four-wave mixing in hot vapor, with detailed analysis in different regimes.

Findings

Noise reduction of up to 3.8 dB below SQL

Generation of entangled twin beams in pulsed regime

Violation of EPR inequality confirming entanglement

Abstract

Using four-wave mixing in a hot atomic vapor, we generate a pair of entangled twin beams in the microsecond pulsed regime near the D1 line of $^{85}$Rb, making it compatible with commonly used quantum memory techniques. The beams are generated in the bright and vacuum-squeezed regimes, requiring two separate methods of analysis, without and with local oscillators, respectively. We report a noise reduction of up to $3.8\pm 0.2$ dB below the standard quantum limit in the pulsed regime and a level of entanglement that violates an Einstein--Podolsky--Rosen inequality.