Variant of the Clauser-Horne-Shimony-Holt inequality

TL;DR

This paper introduces a new Bell inequality derived from the CHSH inequality that offers a tighter bound on entangled qubit correlations and is violated by multiqubit GHZ states, with potential generalizations.

Contribution

It presents a novel Bell inequality stronger than CHSH for two qubits and extends the approach to multiqubit GHZ states, enhancing tests of quantum entanglement.

Findings

Stronger bounds on entangled states compared to CHSH

Violations observed in all GHZ states

Generalizable to n-qubit systems

Abstract

We construct a Bell inequality from the Clauser-Horne-Shimony-Holt inequality for two qubits that provides a stronger bound on the correlations of entangled states than allowed by the CHSH inequality. The argument involved here can be generalized to $n$ qubits. The inequalities obtained are violated by all the generalized Greenberger-Horne-Zeilinger states of multiqubits.