Atomic Theory of the λ Transition in Helium

作者：Richard P. Feynman · 发表于：Physical Review · 年份：1953 · DOI：10.1103/physrev.91.1291 · 被引用次数：494 · 研究领域：Quantum, superfluid, helium dynamics、Advanced Thermodynamics and Statistical Mechanics、Cold Atom Physics and Bose-Einstein Condensates

It is shown from first principles that, in spite of the large interatomic forces, liquid He4 should exhibit a transition analogous to the transition in an ideal Bose-Einstein gas. The exact partition function is written as an integral over trajectories, using the space-time approach to quantum mechanics. It is next argued that the motion of one atom through the others is not opposed by a potential barrier because the others may move out of the way. This just increases the effective inertia of the moving atom. This permits a simpler form to be written for the partition function. A rough analysis of this form shows the existence of a transition, but of the third order. It is possible that a more complete analysis would show that the transition implied by the simplified partition function is actually like the experimental one.