Bell tests for continuous variable systems using hybrid measurements and heralded amplifiers

TL;DR

This paper proposes Bell tests for continuous variable optical systems using hybrid measurements and heralded amplifiers, reducing detection and transmission losses to enable feasible experimental tests.

Contribution

It introduces schemes with amplifiers at the source or parties' labs, lowering the requirements for detection efficiency and losses in Bell tests for continuous variables.

Findings

Amplifiers reduce the impact of losses in Bell tests.

Detection efficiency requirements are significantly lowered.

Transmission losses are mitigated, approaching experimental feasibility.

Abstract

We present Bell tests for optical continuous variable systems, combining both hybrid measurements (i.e. measuring both particle and wave aspects of light) and heralded amplifiers. We discuss two types of schemes, in which the amplifier is located either at the source, or at the parties' laboratories. The inclusion of amplifiers helps to reduce the detrimental effect of losses in the setup. In particular, we show that the requirements in terms of detection efficiency and transmission losses are significantly reduced, approaching the experimentally accessible regime.