Maximal qubit violation of n-local inequalities in quantum network

TL;DR

This paper derives the maximum violation of n-local inequalities in complex quantum networks, enhancing understanding of quantum correlations in chain and star-shaped configurations.

Contribution

It provides a systematic method to determine the maximal violation of n-local inequalities for arbitrary two-qubit states in complex network structures.

Findings

Maximal violation of n-local inequalities derived for chain and star networks.

Results applicable to arbitrary two-qubit states in complex networks.

Deeper insight into quantum correlations in multi-party quantum networks.

Abstract

Source independent quantum networks are considered as a natural generalization to the Bell scenario where we investigate the nonlocal properties of quantum states distributed and measured in a network. Considering the simplest network of entanglement swapping, recently Gisin et. al. and Andreoli et. al. independently provided a systematic characterization of the set of quantum states leading to violation of the so-called 'bilocality' inequality. In this work, we consider the complexities in the quantum networks with an arbitrary number of parties distributed in chain-shaped and star-shaped networks. We derive the maximal violation of the 'n-local' inequality that can be achieved by arbitrary two-qubit states for such chain and star-shaped networks. This would further provide us deeper understanding of quantum correlations in complex structures.