Quantum Discord for d circle times 2 Systems

Author(s)

Ma, Zhihao ^{[1, 2]} ; Chen, Zhihua ^{[3, 4]} ; Fanchini, Felipe Fernandes ^[5] ; Fei, Shao-Ming ^{[6, 7]}

Affiliation

^[1] UCL, Dept Phys & Astron, London WC1E 6BT - England

^[2] Shanghai Jiao Tong Univ, Dept Math, Shanghai 200240 - Peoples R China

^[3] Zhejiang Univ Technol, Coll Sci, Dept Math, Hangzhou 310023, Zhejiang - Peoples R China

^[4] Natl Univ Singapore, Ctr Quantum Technol, Singapore 117543 - Singapore

^[5] Univ Estadual Paulista, Fac Ciencias, Dept Fis, Sao Paulo - Brazil

^[6] Capital Normal Univ, Sch Math Sci, Beijing 100048 - Peoples R China

^[7] Max Planck Inst Math Sci, D-04103 Leipzig - Germany

• Document type: Journal article
• Source: SCIENTIFIC REPORTS; v. 5, JUN 3 2015.
• Web of Science Citations: 8

Abstract

We present an analytical solution for classical correlation, defined in terms of linear entropy, in an arbitrary d circle times 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 circle times 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. (AU)

• FAPESP's process: 12/50464-0 - A study of quantum correlations in open quantum systems
• Grantee: Felipe Fernandes Fanchini
• Support type: Regular Research Grants
• FAPESP's process: 08/57856-6 - National Institute of Science and Technology - Quantum Information
• Grantee: Amir Ordacgi Caldeira
• Support type: Research Projects - Thematic Grants