Violation of Svetlichny's inequality in a system of spins $j$

TL;DR

This paper introduces a unified scheme to demonstrate the violation of Svetlichny's inequality across arbitrary spin systems, expanding understanding of quantum correlations beyond spin-1/2 particles and revealing maximal violations in various regimes.

Contribution

The study develops a universal method to violate Svetlichny's inequality in multi-particle systems of arbitrary spin, including fermions and bosons, with maximal violations achieved in several cases.

Findings

Maximal quantum violation of SI for all fermion systems.

SI violation in boson systems with spin $j extgreater=2$ for any number of particles.

SI violation for up to 7 particles when $j=1$.

Abstract

Quantum multi-particle correlations are one of the most intriguing properties of quantum entanglement, arising from collective entangled states of multiple particles. Svetlichny's inequality (SI) was the first method proposed to test the existence of such correlations. Previous studies have primarily focused on $1/2$-spin particle systems. In this paper, we present a unified scheme that enables the violation of SI in arbitrary non-zero spin particle systems. Specifically, for all fermion systems, our scheme achieves the maximal quantum violation of SI for any number of particles. For boson systems, when the particle spin $j\geq2$, our scheme consistently realizes the violation of SI for any number of particles. When the particle spin $j=1$, our scheme can yield SI violation for up to $7$ particles. Furthermore, as the particle spin $j$ approaches infinity, our scheme achieves the maximal quantum violation of SI. To obtain these results, we also prove that the upper bound of Svetlichny's operator within the framework of local hidden variable theory is $\sqrt{2^{N+1}}$. These findings not only enhance our understanding of quantum correlations across various particle systems but also provide valuable insights for the development of quantum communication protocols that utilize entanglement and non-locality in multi-particle configurations.