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MiS Preprint
40/2015

Quantum Discord for $d\otimes2$ Systems

Zhi-Hao Ma, Zhi-Hua Chen, Felipe Fernandes Fanchini and Shao-Ming Fei

Abstract

We present an analytical solution for classical correlation, defined in terms of linear entropy, in an arbitrary $d\otimes 2$ system when the second subsystem is measured. We show that the optimal measurements used in the maximization of the classical correlation in terms of linear entropy, when used to calculate the quantum discord in terms of von Neumann entropy, result in a tight upper bound for arbitrary $d\otimes 2$ systems. This bound agrees with all known analytical results about quantum discord in terms of von Neumann entropy and, when comparing it with the numerical results for $10^6$ two-qubit random density matrices, we obtain an average deviation of order $10^{-4}$. Furthermore, our results give a way to calculate the quantum discord for arbitrary $n$-qubit GHZ and W states evolving under the action of the amplitude damping noisy channel.

Received:
Aug 12, 2015
Published:
Aug 14, 2015
PACS:
03.67.Mn, 03.65.Ud

Related publications

inJournal
2015 Journal Open Access
Zhi-Hao Ma, Zhi-Hua Chen, Felipe Fernandes Fanchini and Shao-Ming Fei

Quantum discord for \(d \otimes 2\) systems

In: Scientific reports, 5 (2015), p. 10262