Eur. Phys. J. D (2014) 68: 87
https://doi.org/10.1140/epjd/e2014-40518-8

Regular Article

Quantum discord through the generalized entropy in bipartite quantum states

Department of Physics, Huazhong Normal University, Wuhan 430079, P.R. China

^a e-mail: xwhou@phy.ccnu.edu.cn

Received: 22 August 2013
Received in final form: 17 November 2013
Published online: 23 April 2014

Abstract

The quantum discord originally defined in terms of von Neumann entropy has been widely applied to various quantum systems. In this paper, using Renyi entropy, we propose another kind of quantum discords, where the discord recently defined in terms of Tsallis entropy is considered for comparison. Numerical simulations and explicit expressions of these discords are given for random two-qubit states, a class of two-qutrit state, and Werner state and isotropic state in arbitrary dimensions. It is shown that Renyi entropic discord is suitable to capture quantum correlations. In particular, for some quantum states Tsallis entropic discord can be negative. These shed new light on the understanding of the generalized discords in high-dimensional mixed states.