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

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.

References in corpus (11)

• Quantum discord and the power of one qubit
• Experimental quantum computing without entanglement
• Quantum discord and quantum phase transition in spin chains
• Quantum discord for general two--qubit states: Analytical progress
• Computing quantum discord is NP-complete
• Optimal measurements to access classical correlations of two-qubit states
• Quantum discord for two-qubit X states: Analytical formula with very small worst-case error
• Optimality of Gaussian Discord
• Scaling of quantum discord in spin models
• Tomographic causal analysis of two-qubit states and tomographic discord
• Tomographic discord for a system of two coupled nanoelectric circuits

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• On the quantum discord of general X states
• One-way Quantum Deficit and Decoherence for Two-qubit $X$ States
• Tomographic discord for a system of two coupled nanoelectric circuits
• Maximally genuine multipartite entangled mixed X-states of N-qubits
• A characterization of entangled two-qubit states via partial-transpose-moments
• Phase diagram for the one-way quantum deficit of two-qubit X states
• Local available quantum correlations of non-symmetric X states
• One-way quantum deficit for $2\otimes d$ systems
• Extremal properties of conditional entropy and quantum discord for XXZ symmetric quantum states
• Realizing quantum advantage without entanglement in single-photon states