2019/08/12 by Ana Marı́a Cetto, Cetto, Ana María, Andrea Valdés-Hernández +3 · 1 citation
Computer Science · Physics and Astronomy · #FOS: Physical sciences #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum Physics (quant-ph)
paper · pdf · doi:10.48550/arxiv.1908.04225
openalex publication_date 2019/08/12 · openalex created_date 2022/07/19 · openalex updated_date 2026/07/28
Spin is a fundamental and distinctive property of the electron, having\nfar-reaching consequences in wide areas of physics. Yet, further to its\nassociation with an angular momentum, the physics underpinning its formal\ntreatment remains obscure. In this work we propose to advance in disclosing the\nmeaning behind the formalism, by first recalling some basic facts about the\none-particle spin operator. Consistently informed by and in line with the\nquantum formalism, we then proceed to analyse in detail the spin projection\noperator correlation function CQ( boldsymbola, boldsymbolb) =\n\⟨(\\σ\⋅ boldsymbola)(\\σ\⋅ boldsymbolb)\⟩\nfor the bipartite singlet state, and show it to be amenable to an unequivocal\nprobabilistic reading. In particular, the calculation of CQ( boldsymbola,\n boldsymbolb) entails a partitioning of the probability space, which is\ndependent on the directions ( boldsymbola, boldsymbolb). The derivation\nof the CHSH- or other Bell-type inequalities, on the other hand, does not\nconsider such partitioning. This observation puts into question the\napplicability of Bell-type inequalities to the bipartite singlet spin state.\n