Entanglement and nonlocality in multi-particle systems  

作　　者：Margaret D. Reid (1) Qiong-Yi He (1) Peter D. Drummond (1) 

机构地区：[1]1. ARC Centre of Excellence for Quantum-Atom Optics, Centre for Atom Optics and Ultrafast Spectroscopy, Swinburne University of Technology, Melbourne, 3122, Australia

出　　处：《Frontiers of physics》2012年第1期72-85,共14页物理学前沿（英文版）

摘　　要：Entanglement, the Einstein-Podolsky Rosen （EPR） paradox and Bell＇s failure of local-hidden- variable （LHV） theories are three historically famous forms of ＂quantum nonlocality＂. We give experimental criteria for these three forms of nonlocality in multi-particle systems, with the aim of better understanding the transition from microscopic to macroscopic nonlocality. We examine the nonlocality of N separated spin J systems. First, we obtain multipartite Bell inequalities that address the correlation between spin values measured at each site, and then we review spin squeezing inequal- ities that address the degree of reduction in the variance of collective spins. The latter have been particularly useful as a tool for investigating entanglement in Bose Einstein eondensates （BEC）. We present solutions for two topical quantum states： multi-qubit Greenberger-Horne Zeilinger （GHZ） states, and the ground state of a two-well BEC.Entanglement, the Einstein-Podolsky Rosen （EPR） paradox and Bell＇s failure of local-hidden- variable （LHV） theories are three historically famous forms of ＂quantum nonlocality＂. We give experimental criteria for these three forms of nonlocality in multi-particle systems, with the aim of better understanding the transition from microscopic to macroscopic nonlocality. We examine the nonlocality of N separated spin J systems. First, we obtain multipartite Bell inequalities that address the correlation between spin values measured at each site, and then we review spin squeezing inequal- ities that address the degree of reduction in the variance of collective spins. The latter have been particularly useful as a tool for investigating entanglement in Bose Einstein eondensates （BEC）. We present solutions for two topical quantum states： multi-qubit Greenberger-Horne Zeilinger （GHZ） states, and the ground state of a two-well BEC.

关 键 词：ENTANGLEMENT quantum nonlocality MULTI-PARTICLE two-well Bose-Einstein condensates（BEC） 

分 类 号：O413.1[理学—理论物理] O412.1[理学—物理]