R. K. Pathria

Finite-size scaling of O(n) models in higher dimensions

We propose a finite-size scaling hypothesis for O(n) models, with n ⩾ 2, in geometry Ld−d′ × ∞d′, with d > 4 and d′ ⩽ 2, subject to periodic boundary conditions. Several predictions, for T < Tc as well as T ≈ Tc, are made and are verified analytically for the special case of the spherical model (n = ∞).

Fluctuations and superfluidity in finite systems

Abstract Considerations of the density fluctuations and the ground-state occupancy of a finite Bose-Einstein system lead to a workable criterion for the onset of superfluidity. The criterion is applied to thin films and narrow channels.