Shao Xiao-Qiang

Dissipative creation of three-dimensional entangled state in optical cavity via spontaneous emission

We present a dissipative protocol to engineer two

Entanglement sudden death of two atoms interacting with a cavity via the two-photon process in a strong-driving-assisted system ∗

^{87}Rb

Implementation of nonlocal Bell-state measurement and quantum information transfer with weak Kerr nonlinearity

atoms into a form of three-dimensional entangled state via spontaneous emission. The combination of coupling between ground states via microwave fields and dissipation induced by spontaneous emission make the current scheme deterministic and a stationary entangled state can always be achieved without state initialization. Moreover, this scheme can be straightforwardly generalized to preparation of an

Measurement-induced disturbance and nonequilibrium thermal entanglement in a qutrit qubit mixed spin XXZ model ∗

N

Pairwise thermal entanglement in a three-qubit Heisenberg XX model with a nonuniform magnetic field and Dzyaloshinski-Moriya interaction

-dimensional entangled state in principle.

Three-qubit Fredkin gate based on cavity quantum electrodynamics

We examine the entanglement dynamics between two strongly driven atoms off-resonantly coupled with a single-mode cavity via the two-photon process with the help of negativity in two different types of initial states. The results show that entanglement sudden death may occur under both the above conditions and the sudden death effect can be monitored by modulating the atom–cavity detunings. Furthermore, we also find an atomic decoherence-free subspace so that the initial entanglement between two atoms remains invariable in application.

Repulsive Casimir Force in a Cavity Comprising a Dielectric with Output Coupling

We propose a protocol to implement the nonlocal Bell-state measurement, which is nearly determinate with the help of weak cross-Kerr nonlinearities and quantum non-destructive photon number resolving detection. Based on the nonlocal Bell-state measurement, we implement the quantum information transfer from one place to another. The process is different from conventional teleportation but can be regarded as a novel form of teleportation without entangled channel and classic communication.

Implementation of positive-operator-value measurements for single spin qubit via Heisenberg model

We investigate the dynamics of nonequilibrium thermal quantum correlation of a qutrit-qubit mixed spin system coupled to two bosonic reservoirs at different temperatures using measurement-induced disturbance. The effects of initial states of the spins and temperatures of the reservoirs on measurement-induced disturbance and entanglement are discussed. The results demonstrate that measurement-induced disturbance is more robust than entanglement against the influence of both these factors and there is no sudden death phenomenon for measurement-induced disturbance. The dependences of steady-state measurement-induced disturbance and entanglement on coupling constant and anisotropy parameter are also studied. Steady-state entanglement vanishes for a ferromagnetic qutrit-qubit model, while steady-state measurement-induced disturbance exists for both the antiferromagnetic and ferromagnetic cases. Appropriately modulating the coupling constant and anisotropy parameter can strengthen quantum correlation.

One-step implementing three-qubit phase gate via manipulating rf SQUID qubits in the decoherence-free subspace with respect to cavity decay

Pairwise thermal entanglement in a three-qubit Heisenberg XX model is investigated when a nonuniform magnetic field and the Dzyaloshinski—Moriya interaction are included. We find that the nonuniform magnetic field and Dzyaloshinski—Moriya interaction are the more efficient control parameters for the increase of entanglement and critical temperature. For both the nearest neighbour sites and the next nearest neighbour sites, the magnetic field can induce entanglement to a certain extent and the Dzyaloshinski—Moriya interaction can enhance the entanglement to a stable value. The steady value of the nearest neighbour site entanglement C12 is larger than the next nearest neighbour site entanglement C13. An interesting phenomenon is that the entanglement curve of C12 appears a peak value when the Dzyaloshinski—Moriya interaction is considered in a nonuniform magnetic field.

Simplified optical quantum-information processing via weak cross-Kerr nonlinearities

This paper presents a scheme for implementing a Fredkin gate on three modes of a cavity. The scheme is based on the dispersive atom-cavity interaction. By modulating the cavity frequency and the atomic transition frequency appropriately, it obtains the effective form of nonlinear interaction between photons in the three-mode cavity. This availability is testified via numerical analysis. It also considers both the situations with and without dissipation.