A measure for maximum similarity between outcome states

Abstract

We propose a measure to quantify correlations in a bipartite quantum system of two quibits by assessing the minimum difference between outcome states of a subsystem by performing a local measurement on the other subsystem. This maximum similarity measure is a monotone function of the concurrence for pure states of two qubits; for mixed states it accounts for entanglement, dissonance, and classical correlations. Besides, we found a closed formula for evaluating the similarity degree of an arbitrary mix state of two two-dimensional systems. © CopyrightEPLA, 2015.