The complexity-theoretic Bell inequality

• 来源期刊: 国家科学评论（英文版）
• 年，卷（期）: 2019,（1）
• 页码范围: 21
• 页数: 1页
• 语种: 英文
• DOI: 10.1093/nsr/nwy075

摘要

'I am a quantum engineer,but on Sundays I have principles.'John Stewart Bell once started a colloquium with these words.The Bell inequality,one of the most important and fundamental results of quantum physics,probably originates from a flash of insight he had on a Sunday afternoon around 1964.The inequality proves Einstein wrong and prorides a concrete method to tell apart quantum mechanics and classical theories.A variant of the Bell inequality,known as the CHSH inequality named after John Clauser,Michael Home,Abner Shimony,and Richard Holt,states that |S| ≤ 2 in any classical theories where S =〈AoBo + AoB1 + AtBo-A1B1〉,and Ai,Bj are observables;however,quantum mechanically it is possible to violate the inequality and have | S | =2/2.