Detecting Bell Correlations in Multipartite Non-Gaussian Spin States

Physical Review Letters, vol. 131, pp. 070201

Abstract

We expand the toolbox for studying Bell correlations in multipartite systems by introducing permutationally invariant Bell inequalities (PIBIs) involving few-body correlators. First, we present around twenty families of PIBIs with up to three- or four-body correlators, that are valid for an arbitrary number of particles. Compared to known inequalities, these show higher noise robustness, or the capability to detect Bell correlations in highly non-Gaussian spin states. We then focus on finding PIBIs that are of practical experimental implementation, in the sense that the associated operators require collective spin measurements along only a few directions. To this end, we formulate this search problem as a semidefinite program that embeds the constraints required to look for PIBIs of the desired form.

Authors 4

1. Jiajie Guo

   Peking University · Collaborative Innovation Center of Quantum Matter

   Affiliation as printed

   State Key Laboratory for Mesoscopic Physics, School of Physics, Frontiers Science Center for Nano-optoelectronics, & Collaborative Innovation Center of Quantum Matter, Peking University, Beijing 100871, China

2. Jordi Tura Aachen Instituut-Lorentz 〈aQaL〉 Applied Quantum Algorithms – Leiden

   Leiden University

   Affiliation as printed

   Instituut-Lorentz, Universiteit Leiden, P.O. Box 9506, 2300 RA Leiden, The Netherlands

   ⟨aQaL⟩ Applied Quantum Algorithms Leiden, The Netherlands

3. Qiongyi He corresponding

   Peking University · Shanxi University · Collaborative Innovation Center of Quantum Matter

   Affiliation as printed

   Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China

   Hefei National Laboratory, Hefei 230088, China

   Peking University Yangtze Delta Institute of Optoelectronics, Nantong 226010, Jiangsu, China

   State Key Laboratory for Mesoscopic Physics, School of Physics, Frontiers Science Center for Nano-optoelectronics, & Collaborative Innovation Center of Quantum Matter, Peking University, Beijing 100871, China

4. Matteo Fadel

   ETH Zurich

   Affiliation as printed

   Department of Physics, ETH Zürich, 8093 Zürich, Switzerland