Nonlocality of Symmetric States

TL;DR

This paper investigates the non-local properties of permutation symmetric states of n-qubits, extending Hardy paradoxes and inequalities to demonstrate that all such symmetric states exhibit non-locality, with different entanglement classes showing distinct non-local features.

Contribution

It introduces generalized Hardy paradoxes and inequalities for symmetric states, linking entanglement classes to specific non-local behaviors, a novel extension in quantum non-locality research.

Findings

All symmetric states exhibit non-locality.

Different entanglement classes show distinct non-local features.

Inequalities are violated by all states of a specific entanglement class.

Abstract

In this paper we study the non-local properties of permutation symmetric states of n-qubits. We extend the bipartite Hardy paradox and the associated CH-inequality to n-party permutation symmetric states to show that all symmetric states exhibit non-locality. Natural extensions of both the paradoxes and the inequalities are developed which relate different entanglement classes to different non-local features. We define inequalities which are violated by all states of one entanglement class, whereas there are states outside that class which do not violate.