论文标题
超级流体过渡的二维bose气体中的声音传播
Sound propagation in a two-dimensional Bose gas across the superfluid transition
论文作者
论文摘要
由最近的物理实验的动机。莱特牧师。 121，145301（2018），我们使用经典的场动力学研究了在超流体热过渡的二维（2D）bose气体中的声音传播。在过渡温度下方，我们找到了一个Bogoliubov和一个非Bogoliubov模式，在其上方，我们找到了正常的声音模式和扩散模式，正如我们从动态结构因子中确定的那样。我们对实验过程的模拟与测量的速度一致，并表明在过渡温度以下测量值检测到Bogoliubov模式。在过渡上方，他们要么检测到低密度或弱相互作用的正常声音模式，要么检测到高密度或强相互作用的扩散模式。作为一个关键观察，我们讨论了弱耦合方案，在该耦合方案中，与流体动力学相反，非阳性模式的速度高于Bogoliubov模式。我们建议通过踩踏密度扰动来检测这种状态
Motivated by recent experiments in Phys. Rev. Lett. 121, 145301 (2018), we study sound propagation in a two-dimensional (2D) Bose gas across the superfluid-thermal transition using classical field dynamics. Below the transition temperature we find a Bogoliubov and a non-Bogoliubov mode, above it we find the normal sound mode and the diffusive mode, as we determine from the dynamical structure factor. Our simulations of the experimental procedure agree with the measured velocities, and show that below the transition temperature the measurements detect the Bogoliubov mode. Above the transition, they either detect the normal sound mode for low densities or weak interactions, or the diffusive mode for high densities or strong interactions. As a key observation, we discuss the weak coupling regime in which the non-Bogoliubov mode has a higher velocity than the Bogoliubov mode, in contrast to a hydrodynamic scenario. We propose to detect this regime via step-pulse density perturbation, which simultaneously detects both sound modes
