A CHSH Test of Bell's Inequality

Silvio Paolo sorella

Chae-Yeun Park, Hyunseok Jeong

We study an asymmetric form of the two-mode entangled coherent state (ECS), where the two local amplitudes have different values, as a tool for testing the Bell-Clauser-Horne-Shimony-Holt (Bell-CHSH) inequality. We find that the asymmetric ECSs have obvious advantages over the symmetric form of ECSs in testing the Bell-CHSH inequality. We further study an asymmetric strategy in distributing an ECS over a lossy environment and find that such a scheme can significantly increase violation of the inequality.

Silvio Paolo sorella

Fırat Diker, Mandarino, Antonio

In this work, we show that the well-known Bell inequality in the Clauser-Horne-Shimony-Holt (CHSH) formulation serves not only as a non-locality test but also as a tool to prove KCBS-type contextuality. For this purpose, we investigate the symmetric family of two-qubit states that can be mapped to qutrit states (three-level quantum states) and show that they exhibit a contextual description, as evidenced by the KCBS-type inequality. Later, we apply the CHSH test to them and find a new non-contextuality bound for this test. This shows that the CHSH inequality can be modified to serve as a KCBS-type contextuality test by changing the limit. Also, the number of measurements required is four, fewer than the KCBS test's five. We discuss the new bound concerning the monogamy problem.

Akio Yoshizawa, Hidemi Tsuchida

A report is presented of observed violation of the Clauser-Horne-Shimony-Holt (CHSH) inequality, a particular form of Bell's inequality, in polarisation-entangled photon pairs in the 1550 nm band. Accidental coincidences were included as detected in the S value evaluation of the CHSH inequality. A 10.5 km fibre was used as a quantum channel.

Pierre A. Millette