Unified scheme for correlations using linear relative entropy

Abstract

A linearized variant of relative entropy is used to quantify in a unified scheme the different kinds of correlations in a bipartite quantum system. As illustration, we consider a two-qubit state with parity and exchange symmetries for which we determine the total, classical and quantum correlations. We also give the explicit expressions of its closest product state, closest classical state and the corresponding closest product state. A closed additive relation, involving the various correlations quantified by linear relative entropy, is derived.

Quantum discord and its allies: a review of recent progress

“…Here Π ρAB is the closest product state of ρ AB . A similar relation among the same quantities, but by using a linearized variant of relative entropy has also been addressed in [175]. Note here that the above concept of relative entropy-based QD can also be extended to the multipartite domain [174].…”

“…It is important to mention that there are further measures that have been put forward in the last fifteen years or so. These include the ones that have been proposed [134,[178][179][180][181][182][183][184] based on Rényi and Tsallis entropies [185][186][187][188][189][190][191]. Further examples include Refs.…”

“…It is important to mention that there are further measures that have been put forward in the last fifteen years or so. These include the ones that have been proposed [175,[218][219][220][221][222][223][224] based on Rényi and Tsallis entropies [225][226][227][228][229][230][231]. Further examples include [64,211,[232][233][234][235][236][237][238][239][240][241][242][243][244][245][246].…”