Liu Xiansong

Remotely Sharing a Single-Qubit Operation with a Five-Qubit Genuine State

A three-party scheme for remotely sharing a single-qubit operation with Brown state and local operation and classical communication is proposed. Some discussions are made to show its important features, including determinacy symmetry, security, expansibility and nowadays experimental feasibility.

Quantum Correlations in a Family of Bipartite Qubit-Qutrit Separable States

Quantum correlations in a family of bipartite separable qubit-qutrit quantum-classical correlated states are investigated by using two popular measures, i.e., the original quantum discord (OQD) method by Ollivier and Zurek [Phys. Rev. Lett. 88 (2001) 017901] and the measurement-induced disturbance (MID) method by Luo [Phys. Rev. A 77 (2008) 022301]. It is found that both of them are functions of a parameter partially characterizing the concerned states, however, quantum correlations evaluated via the convenient MID method are somewhat overestimated.

Single-Qubit Operation Sharing with Bell and W Product States

Two tripartite schemes are put forward with shared entanglements and Local Operation and Classical Communication (LOCC) for sharing an operation on a remote target sate. The first scheme uses a Bell and a symmetric W states as quantum channels, while the second replaces the symmetric W state by an asymmetric one. Both schemes are treated and compared from the aspects of quantum resource consumption, operation complexity, classical resource consumption, success probability and efficiency. It is found that the latter scheme is better than the former one. Particularly, the sharing can be achieved only probabilistically with the first scheme deterministically with the second one.

Quantum Correlations in a Family of Two-Qubit Separable States

Quantum correlations in a family of two-qubit separable classical-quantum correlated states are intensively studied with four different approaches, namely, quantum discord [Phys. Rev. Lett. 88 (2002) 017901], measurement-induced disturbance (MID) [Phys. Rev. A 77 (2008) 022301], ameliorated MID [J. Phys. A: Math. Theor. 44 (2011) 352002] and quantum dissonance [Phys. Rev. Lett. 104 (2010) 080501]. Quantum correlations captured with different approaches are compared and discussed so that their three distinct features are exposed.

Quantum Discord in any Mixture of Two Bi-Qubit Arbitrary Product States

Quantum discord in any mixture of two bi-qubit arbitrary product states is studied with two different approaches. In the first approach the maximal classical correlations are obtained via numerical computations, while in the second approach they are analytically derived. Quantum correlations captured with both approaches completely coincide, as is in accord with the conclusion of Cen et al. [Phys. Rev. A 83 (2011) 054101]. The symmetry reduction of the concerned states concerning quantum correlations is accomplished. The captured discords are amply analyzed so that some inherent distinct properties are revealed.

Quantum Correlations in Werner Derivatives

Quantum correlations in Werner derivatives are studied with two different approaches, i.e., measurement-induced disturbance (MID) [Phys. Rev. A 77 (2008) 022301] and ameliorated MID (AMID) [J. Phys. A 44 (2011) 352002]. They are derived via strict deductions with MID while numerically calculated via the measurement optimization with AMID. Interestingly, quantum correlations captured with both approaches are completely coincident. Moreover, some distinct features of the quantum correlations and their underlying physics are exposed via analyses and discussions.