Theory of the superfluidity of helium II
Theory of the superfluidity of helium II
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DOI：
10.1103/physrev.60.356
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发表时间：
1941-08-01
期刊：
影响因子：
--
通讯作者：
Landau, L
中科院分区：
文献类型：
--
作者：
Landau, L
通过引入液体密度和速度的算符，实现了任意相互作用粒子系统(液体)的量子化；确定了这些算符之间的对易规则(§1)。根据这一量子化的结果，确定了量子液体光谱中能级分布的一般特征(§2)。研究了氦II的热容与温度的关系(§3)。结果表明，在绝对零度下，量子液体可以具有超流性质(§4)。在非零温度下，发现氦II中可以同时存在两种运动--超流运动和正常运动。这可以用超流和液体的正常部分的概念来描述；氦II中的λ点与液体的“超流”部分的消失有关(§5)。解释了测量氦II的导热系数和粘度的实验；考虑了氦II的热机械效应(§6)。提出了描述氦II宏观运动的流体动力学方程组(§7)。利用这些方程研究了声的传播，证明了氦II中必须存在两种声速(§8)。
The quantization of an arbitrary system of interacting particles (a liquid) is performed by means of introducing the operators of the density and of the velocity of the liquid; the commutation rules between these operators are determined (§ 1). From the results of this quantization the general character of the distribution of the energy levels in the spectrum of a quantum liquid is determined (§ 2). The temperature dependence of the heat capacity of helium II is investigated (§ 3). It is shown that at absolute zero a quantum liquid can possess the property of superfluidity (§ 4). At non-zero temperatures it is found that two motions — a superfluid and a normal — can simultaneously exist in helium II. This can be described by means of the conception of the superfluid and normal parts of the liquid; the λ -point in helium II is connected with the disappearance of the «superfluid» part of the liquid (§ 5). The experiments made to measure the heat conductivity and viscosity of helium II are interpreted; the thermomechanical effects in helium II are considered (§ 6). A system of hydrodynamic equations is advanced describing the macroscopic motion of helium II (§ 7). By means of these equations the propagation of sound is investigated and it is shown that two velocities of sound must exist in helium II (§ 8).