论文标题
在有限温度下，拉曼自旋耦合的玻色气的超流量
Superfluidity of a Raman spin-orbit-coupled Bose gas at finite temperature
论文作者
论文摘要
我们研究了三维弱相互作用的玻色气体的超流量，并在零和有限温度下均以一维拉曼型自旋轨道耦合。使用Bogoliubov近似中的假想时间绿色的函数，我们明确地得出了平面波和零摩托姆阶段中电流响应函数的分析表达式，从中，我们从长波长度和零频率的极限中提取超氟密度。在零温度下，我们检查所得的超流体密度是否与我们先前从相扭方法获得的分析预测完全吻合。这两个结果也满足了在旋转轨道耦合存在下的普遍关系。在有限的温度下，我们发现从平面波相到零摩肌相的过渡附近的超流体密度的显着非单调温度依赖性。我们表明，这种非平凡行为可以从具有相似温度依赖性的声速中理解。非单调温度依赖性也通过Landau的临界速度共享，在此上面，自旋轨道耦合的玻色气体失去了其超流量。我们的结果将有助于进一步的理论和实验研究，对外来自旋轨道耦合量子气体的超流体进行研究。
We investigate the superfluidity of a three-dimensional weakly interacting Bose gas with a one-dimensional Raman-type spin-orbit coupling at both zero and finite temperatures. Using the imaginary-time Green's function within the Bogoliubov approximation, we explicitly derive analytic expressions of the current-current response functions in the plane-wave and zero-momentum phases, from which we extract the superfluid density in the limits of long wavelength and zero frequency. At zero temperature, we check that the resultant superfluid density agrees exactly with our previous analytic prediction obtained from a phase-twist approach. Both results also satisfy a generalized Josephson relation in the presence of spin-orbit coupling. At finite temperature, we find a significant non-monotonic temperature dependence of superfluid density near the transition from the plane-wave phase to the zero-momentum phase. We show that this non-trivial behavior might be understood from the sound velocity, which has a similar temperature dependence. The non-monotonic temperature dependence is also shared by Landau critical velocity, above which the spin-orbit-coupled Bose gas loses its superfluidity. Our results would be useful for further theoretical and experimental studies of superfluidity in exotic spin-orbit coupled quantum gases.
