Transport Phenomena in Helium II
Transport Phenomena in Helium II
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作者：
L. Tisza
F.伦敦大学最近提出了氦II的新概念，根据这个概念，这种液体可以被看作是一种简并的玻色-爱因斯坦气体，也就是说，作为一个系统，其中物质的一部分--比如说，每立方厘米的natoms--以由温度决定的方式分布在激发态上，而其余的--n 0-每立方厘米的natoms--则“凝聚”在最低能级上。如果T0表示简并的温度，则比率/n 0由下式给出：对于理想的玻色-爱因斯坦气体，根据伦敦，s= 3/2，但对于真实的流体，为了适合Keesom的比热测量，应该插入= 5。
F. LONDON1has recently proposed a new conception of helium II, according to which this liquid can be regarded as a degenerate Bose-Einstein gas, that is, as a system in which one fraction of the substance—say,natoms per cm.3—is distributed over the excited states in a way determined by the temperature, while the rest—n0–natoms per cm.3—is 'condensed' in the lowest energy level. IfT0denotes the temperature of degeneracy, the ration/n0is given byFor an ideal Bose-Einstein gas, according to London,s= 3/2, but for the real fluid one should rather inserts= 5 in order to fit Keesom's specific heat measurements.