Entanglement and maximal violation of the CHSH inequality in a system of two spins j: a novel construction and further observations

We study the CHSH inequality for a system of two spin $j$ particles, for generic $j$. The CHSH operator is constructed using a set of unitary, Hermitian operators $\{A_1,A_2,B_1,B_2\}$. The expectation value of the CHSH operator is analyzed for the singlet state $\mid {\psi }_s⟩$. Being $\mid {\psi }_s⟩$ an entangled state, a violation of the CHSH inequality compatible with Tsirelson’s bound is found. Although the construction employed here differs from that of [1], full agreement is recovered.