论文标题
硕士论文：弱相互作用的自旋轨道耦合的玻璃纤维凝结物的激发光谱
Master's Thesis: Excitation Spectrum of a Weakly Interacting Spin-Orbit Coupled Bose-Einstein Condensate
论文作者
论文摘要
研究了与Bravais晶格结合的弱相互作用的，自旋轨道耦合的超电压气体。由合成旋转轨道耦合，超低，中性原子气体的最新实验进步的动机，显示了Bose-Einstein凝结，这是一个分析框架，用于描述超流体状况中的这种系统。这将应用于二维光学晶格中的Rashba自旋轨道耦合的玻色气体。在旋转轨道耦合的情况下，Bose-Einstein凝结的异国性质本身就是一项有趣的研究。此外，当引入光学晶格时，该系统为众多冷凝物质现象提供了高度可控制的实验测试地面。考虑了该系统的五个阶段，并且发现了它们的激发光谱，关键的超氟速度和自由能。在获得自由能时，包括在激发算子中线性线性的术语的效果，并且在这种情况下以前尚未对此术语进行研究。在零温度下的自由能的最小化用于确认文献中报告的相图，通常通过忽略激发的效果来获得。相图中的平面和条纹波相是涉及非零冷凝水力量的超导体中Fulde-Ferrell-Larkin-ovchinnikov状态的骨类似物。
A weakly interacting, spin-orbit coupled, two-component, ultracold Bose gas bound to a Bravais lattice is studied. Motivated by recent experimental advances in the field of synthetically spin-orbit coupled, ultracold, neutral atomic gases showing Bose-Einstein condensation, an analytic framework with which to describe such systems in the superfluid regime is presented. This is applied to a Rashba spin-orbit-coupled Bose gas in a two-dimensional optical lattice. The exotic nature of Bose-Einstein condensation in the presence of spin-orbit coupling is an interesting study by itself. Additionally, when the optical lattice is introduced, the system provides a highly controllable experimental testing ground for numerous condensed matter physics phenomena. Five phases of the system are considered, and their excitation spectra, critical superfluid velocities and free energies are found. In obtaining the free energy, the effects of terms in the Hamiltonian that are linear in excitation operators are included, and such terms have not been studied previously in this context. Minimization of the free energy at zero temperature is used to confirm the phase diagrams reported in the literature, where it has usually been obtained by neglecting the effect of excitations. The plane and stripe wave phases in the phase diagram are bosonic analogues of Fulde-Ferrell-Larkin-Ovchinnikov states in superconductors involving nonzero condensate momenta.
