Strong violations of Bell-type inequalities for Werner-like states

TL;DR

This paper demonstrates that Werner-like states can violate Bell-type inequalities over a broader parameter range using unbalanced homodyne detection, highlighting stronger nonlocal correlations than previously shown.

Contribution

It introduces an unbalanced homodyne detection scheme to reveal Bell inequality violations in Werner-like states over an extended parameter range.

Findings

Violations of Bell-Wigner and Janssens inequalities for a large p range.

Range of violation exceeds that of Clauser-Horne inequality.

Violations occur where Werner-like states are nonseparable.

Abstract

We investigate the violation of Bell-type inequalities for two-qubit Werner-like states parametrized by the positive parameter 0<p<1. We use an unbalanced homodyne detection scheme to obtain the quantum mechanical probabilities. A violation of the Bell-Wigner and Janssens inequalities is obtained for a large range of the parameter p. The range given by these inequalities is greater than the one given by the Clauser-Horne inequality. The range in which a violation is attained actually coincides with the range where the Werner-like states are known to be nonseparabel, i.e., for p>1/3. However, the improvement over the Clauser-Horne inequality is achieved at the price of restricting the class of possible local hidden variable theories.