Three-observer Bell inequality violation on a two-qubit entangled state

TL;DR

This paper experimentally demonstrates that a two-photon entangled state can violate two Bell inequalities simultaneously using weak measurements, highlighting potential applications in quantum cryptography and randomness certification.

Contribution

First experimental demonstration of simultaneous violation of two Bell inequalities on a two-qubit entangled state using weak measurements.

Findings

Achieved large double Bell inequality violation experimentally.

Potential applications in Quantum Key Distribution and Quantum Random Number Generation.

Confirmed feasibility of simultaneous Bell violations with weak measurements.

Abstract

Bipartite Bell inequalities can be simultaneously violated by two different pairs of observers when weak measurements and signaling is employed. Here we experimentally demonstrate the violation of two simultaneous CHSH inequalities by exploiting a two-photon polarization maximally entangled state. Our results demonstrate that large double violation is experimentally achievable. Our demonstration may have impact for Quantum Key Distribution or certification of Quantum Random Number generators based on weak measurements.