Bell inequalities tailored to maximally entangled states

TL;DR

This paper introduces a new class of Bell inequalities designed specifically to detect maximally entangled states, with analytical bounds and proofs that these states attain the quantum maximum, enhancing device-independent quantum protocols.

Contribution

The authors develop Bell inequalities tailored for maximally entangled states, deriving their bounds and proving their attainability by such states, advancing quantum nonlocality tests.

Findings

Derived tight classical, non-signalling, and quantum bounds for the inequalities.

Proved that maximally entangled states attain the quantum bound.

Inequalities applicable to arbitrary measurement settings.

Abstract

Bell inequalities have traditionally been used to demonstrate that quantum theory is nonlocal, in the sense that there exist correlations generated from composite quantum states that cannot be explained by means of local hidden variables. With the advent of device-independent quantum information protocols, Bell inequalities have gained an additional role as certificates of relevant quantum properties. In this work we consider the problem of designing Bell inequalities that are tailored to detect maximally entangled states. We introduce a class of Bell inequalities valid for an arbitrary number of measurements and results, derive analytically their tight classical, non-signalling and quantum bounds and prove that the latter is attained by maximally entangled states. Our inequalities can therefore find an application in device-independent protocols requiring maximally entangled states.