Tripartite thermal correlations in an inhomogeneous spin–star system

Abstract

We exploit the tripartite negativity to study the thermal correlations in a tripartite system, that is, the three outer spins interacting with the central one in a spin–star system. We analyse the dependence of such correlations on the homogeneity of interactions, starting from the case where central–outer spin interactions are dentical and then focusing on the case where the three coupling constants are different. We single out some important differences between the negativity and the concurrence.