Researches On Quantum Correlation Control And Transfer Of Inhomogeneous Heisenberg Spin Chain

Quantum communication becomes a focus on the research of quantum physics and information science in recent years, the quantum correlation(quantum entanglement and quantum discord) is closely related to communication process, because of the rich entanglement affections in solid-state physics system of the Heisenberg spin model, so the model widely used as the channel in quantum communication has been researched extensively. Quantum correlation’s dynamics evolution features of Heisenberg XXZ spin chain with Dzyaloshinskii-Moriya( DM) interaction under external magnetic field are investigated in this thesis. This thesis mainly studied around the various correlations in two-qubits Heisenberg spin chain model, mainly including the following three contents:Firstly, we analyzed the DM interaction, external magnetic strength, the purity of the initial states and other parameters’ influence on quantum entanglement and quantum discord of Heisenberg XXZ spin chain. It is found that quantum correlation of anisotropic Heisenberg XXZ spin chain can be regulated effectively by changing magnetic field intensity B and magnetic field uniformity cos? of the external magnetic field. Under the effects of DM interaction between qubits, quantum correlation show sudden death and revive in the dynamics evolution process; But DM interaction has a critical value CZD which is connected with other parameters of the quantum system. Only when z CZD ?D,can obvious sudden death and revive be observed with the given parameters.Secondly, we also investigated the thermal quantum correlation of Heisenberg XXZ spin chain with DM interaction under external magnetic. Results show that DM interaction can increase the thermal correlation and stronger the DM interaction the more obvious enhancement of effect. Thermal quantum correlation can be effectively controlled under a inhomogeneous magnetic field. Within inhomogeneous magnetic field limits, a relatively stable area, in which a thermal quantum correlate value is almost unconnected with the spin coupling coefficient in z direction, can be formed.At last, We studied quantum communication transfer through two XXZ spin chains with three site and DM interactions and phase shift. It is shown that both interaction including the purity of the initial states, DM interaction the three-site interaction and phase shift can enhance the entanglement. Also we found that, using the initial target states ? 01 ?10? / 2 or in its mixed state, is more suitable for quantum correlation transfer in this system. Through comparative study, it is found that the stronger three site obviously increased the range of quantum entanglement,whether the DM interaction significantly accelerated the vibration of the entanglement over time. Both of them can improve the quality of information transmission in certain extent. The further studies shown that, neither magnetic strength or phase shift failed to improve the quality of the entanglement dynamics evolution effectively.