Bogoliubov Theory for a Superfluid Bose Gas Flowing in a Random Potential: Stability and Critical Velocity
Bogoliubov Theory for a Superfluid Bose Gas Flowing in a Random Potential: Stability and Critical Velocity
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超流玻色气体随机势流动的 Bogoliubov 理论：稳定性和临界速度
DOI：
10.1007/s10909-017-1827-6
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发表时间：
2017
影响因子：
2
通讯作者：
Haga Taiki
中科院分区：
文献类型：
--
作者：
出倉駿;小林浩和;池田龍一;前里光彦;久保田佳基;北川宏;Haga Taiki;Haga Taiki
研究了弱相互作用玻色气体在随机势场中流动的稳定性和临界速度。通过将Bogoliubov理论应用于具有定常流动的无序玻色系统，确定了凝聚密度和超流密度作为无序强度、流速和温度的函数。根据流体动力学激励谱计算了稳定流变为不稳定流的临界流速。我们还表明，在二维的临界速度强烈依赖于系统的大小。
We investigate the stability and critical velocity of a weakly interacting Bose gas flowing in a random potential. By applying the Bogoliubov theory to a disordered Bose system with a steady flow, the condensate density and the superfluid density are determined as functions of the disorder strength, flow velocity, and temperature. The critical velocity, at which the steady flow becomes unstable, is calculated from the spectrum of hydrodynamic excitation. We also show that in two dimensions the critical velocity strongly depends on the system size.