论文标题
带有Zeeman场的光学晶格中的自旋轨道耦合的玻璃纤维耦合bose-Einstein凝结物的平面和条纹波阶段
Plane and Stripe Wave Phases of a Spin-Orbit Coupled Bose-Einstein Condensate in an Optical Lattice with a Zeeman Field
论文作者
论文摘要
研究了带有外部Zeeman场上的二维平方晶格上的弱相互作用，自旋轨道耦合的稀释的稀释的bose气体。我们探索涉及非零冷凝水矩的系统的平面和条纹波阶段，这是当zeeman场低于临界值时发生的。使用Bogoliubov理论和两种不同的途径发现它们的激发光谱。讨论了每种方法获得激发光谱的有效性，并发现对最低单粒子带上的投影在平面波相中是一个极好的近似值，而在条纹波相中，它是一个差的近似值。虽然平面波相在其单个冷凝水动量下具有最小的声子，揭示了激发的非零声速，但条带波相在其两个冷凝水矩处具有二次最小值，显示了激发的零声速。我们讨论了两个以上的冷凝水动量的存在对于这两个阶段之间的这些差异至关重要。此外，强调，条纹波相中的零声速是晶格效应，因为对同一相的连续研究显示了非零声音速度。
A weakly interacting, spin-orbit coupled, ultracold, dilute Bose gas on a two-dimensional square lattice with an external Zeeman field is studied. We explore the plane and stripe wave phases of the system involving nonzero condensate momenta, which occur when the Zeeman field is below a critical value. Their excitation spectra are found using Bogoliubov theory and by two different routes. The validity of each method to obtain the excitation spectrum is discussed, and it is found that projection on the lowest single-particle band is an excellent approximation in the plane wave phase, while it is a poor approximation in the stripe wave phase. While the plane wave phase has a phonon minimum at its single condensate momentum, revealing a nonzero sound velocity of the excitations, the stripe wave phase has quadratic minima at its two condensate momenta showing zero sound velocity of the excitations. We discuss how the presence of more than one condensate momentum is essential for these differences between the two phases. Additionally, it is emphasized that the zero sound velocity in the stripe wave phase is a lattice effect, since continuum studies of the same phase have shown nonzero sound velocity.
