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Analytical solutions and criteria for the quantum discord of two-qubit X-states

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Abstract

Except for a few special states, computing quantum discord remains a complicated optimization process. In this paper, we present analytical solutions for computing quantum discord of the most general class of \(X\)-states and the criteria for each analytical solution to be valid. We discuss parameter regions that correspond to different analytical solutions and explain the underlying reasons for such structure to exist. We apply our formalism to study both arbitrary \(X\)-states and \(X\)-states with certain symmetries. We find that our analytical formalism is in excellent agreement with numerical calculation of quantum discord in both cases.

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Acknowledgments

A. M. T acknowledges the financial support of CONICYT.

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Authors and Affiliations

  1. Departamento de Física, Universidad de Concepción, 160-C, Concepción, Chile

    A. Maldonado-Trapp & Luis Roa

  2. Department of Physics, American University, Washington, DC, 20016, USA

    Anzi Hu

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  1. A. Maldonado-Trapp
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  2. Anzi Hu
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  3. Luis Roa
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Correspondence to A. Maldonado-Trapp.

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Maldonado-Trapp, A., Hu, A. & Roa, L. Analytical solutions and criteria for the quantum discord of two-qubit X-states. Quantum Inf Process 14, 1947–1958 (2015). https://doi.org/10.1007/s11128-015-0943-y

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