Squeezing of a coupled state of two spinors

The notion of spin squeezing involves a reduction in the uncertainty of a component of the spin vector Sâ below a certain limit. This aspect has been studied earlier (Mallesh et al 2000a J. Phys. A: Math. Gen. 33 779, Mallesh et al 2000b J. Phys. A: Math. Gen. 34 3293) for pure and mixed states of definite spin. In this paper, this study has been extended to coupled spin states which do not possess a sharp spin value. A general squeezing criterion has been obtained such that a direct product state for two spinors is not squeezed. The squeezing aspect of entangled states is studied in relation to their spin-spin correlations