Quantum nonlocality for two-mode correlated states based on generalized pseudospin operators

In this Letter, we investigate the quantum nonlocality of two-mode correlated states. We find that the pseudospin formalism [Z.B. Chen, J.W. Pan, G. Hou, Y.D. Zhang, Phys. Rev. Lett. 88 (2002) 040406] generally fails to depict the nonlocality of the states when the photon number difference between the two modes is odd. The formalism is then generalized such that the nonlocality of a two-mode correlated state can be well revealed without regard to the difference. Later we consider the nonlocality of the two-mode intelligent SU(1,1)SU(1,1) states in the generalized formalism and compare our results with the entanglement of the corresponding states.

► Pseudospin formalism fails to show the nonlocality of some two-mode states.
► The formalism is generalized by introducing a new kind of “spin” operators.
► The nonlocality of the two-mode intelligent SU(1,1)SU(1,1) (TMIS) states is discussed.
► The formalism can partially reflect the entanglement of the TMIS states.