Frictional motion of normal-fluid component of superfluid He-3 in aerogel
Frictional motion of normal-fluid component of superfluid He-3 in aerogel
复制标题
超流He-3正常流体组分在气凝胶中的摩擦运动
DOI：
10.1103/physrevb.82.054521
复制
发表时间：
2010
期刊：
影响因子：
--
通讯作者：
et. al.
中科院分区：
文献类型：
--
作者：
K. Obara;C. Kato;et. al.
用四声共振技术研究了高孔隙率气凝胶中液体的超流性。该技术有两个显著的优点：它可以直接确定超流密度和它可以推导出的粘性正常流体组分的输运性质。的共振频率的温度依赖性显示抑制超流性和有限的正常流体分数存在，即使在。还研究了正常流体分量的运动。因为，能量损失变得非常小，尽管剩余的正常流体分量是有限的。这意味着，正常的流体成分是高度约束的气凝胶，因此，耗散机制不能描述在传统的流体动力学模型。我们已经成功地解释了这些结果，通过引入摩擦松弛模型来描述我们的观察，并发现，流场的变化从抛物线（哈根Poiagille粘性流）到平面（Drude摩擦流）上引入气凝胶。用准经典绿色函数方法计算了弛豫时间，再现了实验结果。
The superfluidity of liquidin a high-porosity aerogel has been studied using a fourth-sound resonance technique. This technique has two significant advantages: it can directly determine the superfluid density and it can derive the transport properties of the viscous normal-fluid component. The temperature dependence of the resonance frequency revealed suppression of superfluidity and that a finite normal-fluid fraction exists even at. The motion of the normal-fluid component has also been investigated. As, the energy loss becomes very small, despite a finite amount of the normal-fluid component remaining. This implies that the normal-fluid component is highly constrained by the aerogel, and hence the dissipation mechanism cannot be described in terms of the conventional hydrodynamic model. We have succeeded to explain these results by introducing a frictional relaxation model to describe our observations, and found that the flow field changes from being parabolic (Hagen-Poiseuille viscous flow) to flat (Drude frictional flow) on introducing an aerogel. Numerical calculation of the relaxation time using the quasiclassical Green’s-function method reproduces experimental results.