Entanglement sudden death induced by the Dzialoshinskii-Moriya interaction

In this paper, we study the entanglement dynamics of two-spin Heisenberg XYZ model with the Dzialoshinskii- Moriya （DM） interaction. The system is initially prepared in the Werner state. The effects of purity of the initial state and DM coupling parameter on the evolution of entanglement are investigated. The necessary and sufficient condition for the appearance of the entanglement sudden death （ESD） phenomenon has been deduced. The result shows that the ESD always occurs if the initial state is sufficiently impure for the given coupling parameter or the DM interaction is sufficiently strong for the given initial state. Moreover, the critical values of them are calculated.

Control of entanglement sudden death induced by Dzyaloshinskii-Moriya interaction

We investigate the entanglement dynamics of a system composed of two non-interacting qubits, A and B. A third qubit, C, only has the Dzyaloshinskii-Moriya （DM） spin-orbit interaction with qubit B. We find that the DM interaction can induce the entanglement sudden death （ESD） of the system qubits A and B, and properly mixing the initial state of the system and adjusting the state of qubit C are two effective methods of controlling ESD.

Bipartite Entanglement Dynamics in Three Qubits System with Dzyaloshinskii-Moriya Interaction

We investigate the bipartite entanglement dynamics of the system composed by three qubits A,B,and C.There is no interaction between A and B,and that of C and B is Dzyaloshinskii-Moriya (DM) spin-orbit interaction.We find that the purity of qubits A and B and the initial state of the qubit C are the two effective parameters tocontrol the entanglement dynamics of the bipartite subsystems.This study sheds some lights on the control of quantumentanglement,which would be helpful for quantum information processing.

The influences of dipole-dipole interaction and detuning on the sudden death of entanglement between two atoms in the Tavis-Cummings model

The influences of dipole-dipole interaction and detuning on the entanglement between two atoms with different initial tripartite entangled W-like states in the Tavis Cummings model have been investigated by means of Wootters＇ concurrence, respectively. The results show that the entanglement between the two atoms can be enhanced via appropriately tuning the strength of dipole-dipole interaction of two atoms or the detunings between atom and cavity, and the so-called sudden death effect can he weakened simultaneously.

Suppressing entanglement sudden death by initial system-environment correlation

This paper studies the entanglement dynamics of the system S composed of two non-interactional qubits A and B. The third qubit C is its environment, E, which only interacts with the S qubit B by the Dzyaloshinskii-Moriya spin-orbit coupling. Considering the following states as the whole （S＋E）： the initially S-E correlated state and the separable one, the entanglement of S has no sudden death for the former case. This result sheds some light on the control of quantum entanglement, which will be helpful for quantum information processing.

Entanglement dynamics of two distant atoms in two detuning cavities

We investigate the entanglement dynamics via the concurrence of two distant atoms interacting off-resonantly with two cavity fields in Fock states, respectively. We find that the evolution of entanglement has sudden death and sudden birth phenomena, that with the increase of photon numbers in the two cavities, the alternate frequency of sudden death and sudden birth turns fast, and that the amplitude of concurrence oscillates regularly with oscillation frequency becoming slow when the cavity fields have the same photon numbers. While, the maximum of concurrence declines and the amplitude of concurrence oscillates irregularly when the two cavity fields have different photon numbers. In addition, we find the length of death time is dependent on the initial entanglement.

Controllable entanglement sudden birth of Heisenberg spins

We investigate the Entanglement Sudden Birth （ESB） of two Heisenberg spins A and B. The third controller, qutrit C is introduced, which only has the Dzyaloshinskii-Moriya （DM） spin-orbit interaction with qubit B. We find that the DM interaction is necessary to induce the Entanglement Sudden Birth of the system qubits A and B, and the initial states of the system qubits and the qurit C are also important to control its Entanglement Sudden Birth.

偶极相互作用对T-C模型中原子纠缠突然死亡的影响

求出了初态为x态时Tavis-Cummings模型中两个有偶极相互作用原子的共生纠缠度,分析了偶极相互作用对纠缠的时间演化和纠缠突然死亡(ESD)的影响,以及共生纠缠度与原子间相互作用能的关系。结果表明,偶极相互作用对原子间的纠缠和ESD有显著的影响,会改变纠缠度的振荡周期和振幅,使出现ESD的时间间隔和次数减少。原子间的共生纠缠度与原子间相互作用能有着明显的对应关系,且与原子的初态有关。

线性及非线性介质腔中量子纠缠动力学特征（英文）

如何抑制纠缠突然死亡现象的发生对提高量子纠缠动力学演化性能具有极大的意义,初始纠缠原子分别与非线性N-J-C模型及J-C模型进行相互作用,运用共生纠缠的度量方法分析非线性、耦合强度以及失谐量对纠缠原子动力学演化的影响,寻找避免纠缠突然死亡发生条件。在J-C模型中原子在纠缠演化中发生纠缠突然死亡现象,然而在N-J-C模型中利用介质的非线性和失谐量的影响可以避免纠缠突然死亡的发生,而且一定程度上几乎可以恢复到原子间纠缠的初始值。