Eur. Phys. J. D (2013) 67: 217
https://doi.org/10.1140/epjd/e2013-40336-6

Regular Article

Non-classicalities via perturbing local unitary operations

School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024, P.R. China

^a e-mail: quaninformation@sina.com

Received: 1 June 2013
Received in final form: 14 July 2013
Published online: 29 October 2013

Abstract

We study the nonclassical correlations in a two-qubit state by the perturbing local unitary operation method. We find that the definitions of various non-classicalities including quantum discord (QD), measurement-induced nonlocality (MIN) and so on usually do not have a unique definition when expressed as the perturbation of local unitary operations, so a given non-classicality can lead to different definitions of its dual non-classicality. In addition, it is shown that QD and MIN are not the corresponding dual expressions in a simple set of unitary operations, even though they are in their original definitions. In addition, we also consider the non-classicalities in general 2 ⊗ d dimensional systems.