In this paper, the effect of homogeneous and non-homogeneous magnetic fields as an external noisy on the entanglement dynamics over partial entangled state quantum network is studied. The Dzyaloshiniskii-Moriya (DM) interaction is used to generate entangled network from partially entangled states in the presence of the spin-orbit coupling. The entanglement between any two nodes is quantified using Wootter concurrence. The effect of homogeneous and non-homogeneous magnetic field in presence and absence of the spin coupling on the entanglement between any two nodes of the network is investigated. The results show that the homogeneous magnetic field has no effect on the entanglement without the presence of the spin-orbit interaction. The non-homogeneous magnetic field has a strong impact on the entanglement either with or without spin-orbit couplings. For initially entangled channels, the upper bound does not exceed its initial value, whereas for the channels generated via indirect interaction, the entanglement reaches its maximum value.
In this article we designed a quantum network consists of four nodes using pairs of partial entangled state (Werner-state). The nodes of this network are connected via Dzyaloshiniskii-Moriya (DM) interaction. The entanglement is quantified between all different nodes using Wootters concurrence. It is shown that there is a maximum entangled state generated between two nodes which are connected indirectly. The degree of entanglement depends on the direction of switching the interaction. Index Terms—Entanglement, quantum network, dzyaloshiniskii-Moriya (DM) interaction, Entangled State
The role of spin-orbit interaction in the ground state and thermal entanglement of a Heisenberg
XYZ two-qubit system in the presence of an inhomogeneous magnetic field is investigated. We show that the ground state entanglement tends to vanish suddenly for a certain value of the spin-orbit parameter
D and, when
D crosses its critical value
Dc, the entanglement undergoes a revival. Indeed, when
D crosses its critical value
(Dc), the ground state entanglement tends to its maximum value
(C=1). Also, at finite temperatures there are revival regions in the $D\text{\ensuremath{-}}T$ plane. In these regions, entanglement first increases with increasing temperature and then decreases and ultimately vanishes for temperatures above a critical value. We find that this critical temperature is an increasing function of
D and that the amount of entanglement in the revival region depends on the spin-orbit parameter. Therefore when spin-orbit interaction is included larger thermal entanglement can exist at higher temperatures. We also show that the rate of enhancement of thermal entanglement by
D is not the same for ferromagnetic
(Jz<0) and antiferromagnatic
(Jz>0) chains. The entanglement teleportation via the quantum channel constructed by the above system is also investigated, and the influence of the spin-orbit interaction on the fidelity of teleportation and entanglement of replica states is studied. We show that, by introducing spin-orbit interaction, the entanglement of the replica state and fidelity of teleportation can be increased for the case of
Jz<0. We also argue that a minimal entanglement of the channel is required to realize efficient entanglement teleportation and, in the case of
Jz<0, this minimal entanglement can be achieved by introducing spin-orbit interaction.
With considering the intrinsic decoherence, the dynamic behaviors of quantum entanglement in a three-qubit XXZ Heisenberg system with Dzyaloshinskii-Moriya (DM) interaction and anisotropy for different initial states are investigated. The research result shows that the anisotropy parameter does not affect the system entanglement, however, the intrinsic decoherence has obvious inhibitory effect on entanglement. When the initial state of system is an entangled state, we can obtain the stable value of entanglement by adjusting DM interaction parameters appropriately. As the system initial state is a separation state, entanglement oscillates, and the amplitude of oscillation decays with time periodically, and there will appear the death phenomenon after each oscillation, and with time going on, its concurrence will be zero. When the initial state is entangled, by choosing the proper DM parameter, the three pairs of entanglements oscillate with time and eventually approach to a steady value. The increase of accelerates the decay of concurrence. When the initial state is separated, entanglement oscillates, and the amplitude of oscillation decays with time periodically, and there will appear the death phenomenon after each oscillation, with time going on, its concurrence will be zero. Therefore, the proper initial state and DM interaction parameters can control the concurrence effectively under the intrinsic decoherence, thereby obtaining the preferable entanglement resource.
This paper investigates the entanglement evolution of a two-qubit anisotropic Heisenberg XYZ chain in the presence of Dzyaloshinskii–Moriya interaction. The time evolution of the concurrence is studied for the initial pure entangled states cos θ |00⟩ + sin θ |11⟩ and cos φ |01⟩ + sin φ |10⟩ at zero temperature. The influences of Dzyaloshinskii–Moriya interaction D , anisotropic parameter Δ and environment coupling strength γ on entanglement evolution are analysed in detail. It is found that the effect of noisy environment obviously suppresses the entanglement evolution, and the Dzyaloshinskii–Moriya interaction D acts on the time evolution of entanglement only when the initial state is cos φ |01⟩ + sin φ |10⟩. Finally, a formula of steady state concurrence is obtained, and it is shown that the stable concurrence, which is independent of different initial states and Dzyaloshinskii–Moriya interaction D , depends on the anisotropic parameter Δ and the environment coupling strength γ.
We investigate the exact entanglement dynamics of a two-qubit Heisenberg XXZ chain with Dzyaloshinskii-Moriya (DM) interactions, interacting with an anisotropic spin bath in thermal equi- librium at a temperature T, driven by an external magnetic field B along the z-axis. We establish that, for an initially entangled qubit pair, the DM interactions generate entanglement and enhance the entanglement in the revival region. The effects of the DM interaction are also seen to be very important at high temperatures and for weak coupling between the two qubits where it is seen to preserve entanglement. These effects are weakened when the magnetic field B and the Heisenberg coupling are switched on. If the two-qubits are prepared in an initially separable state, the DM in- teraction instead has a negative effect on their entanglement. On a whole entanglement can better be preserve in the spin chain even at high temperatures by increases the external magnetic field B and the Heisenberg couplings, and by tuning the strength of the DM interaction.