Long Distance Nonlocality Test with Entanglement Swapping and Displacement-Based Measurements

TL;DR

This paper proposes an all-optical setup for long-distance Bell-inequality violation using entanglement swapping, analyzing its robustness under various noise conditions and extending the scenario to multiple parties.

Contribution

It introduces a novel all-optical scheme utilizing simple components for long-distance nonlocality tests and evaluates its robustness against realistic noise sources.

Findings

Bell-inequality violation demonstrated over long distances

Robustness confirmed against phase, amplitude, and dark-count noise

Extension of nonlocality test to up to 6 parties

Abstract

We analyze an all-optical setup which enables Bell-inequality violation over long distances by exploiting probabilistic entanglement swapping. The setup involves only two-mode squeezers, displacements, beamsplitters, and on/off detectors. We analyze a scenario with dichotomic inputs and outputs, and check the robustness of the Bell inequality violation for up to 6 parties, with respect to phase-, amplitude-, and dark-count noise, as well as loss.