Low-Temperature Properties of the Interacting Bose System

概要

論文の詳細を見る
The low-temperature properties of the interacting Bose system at high density are investigated under the random phase approximation and the self-consistent Hartree approximation based on the "normal-mode analysis". To treat rigorously the temperature-dependent "depletion" effect of the particles in the zero-momentum level, a new approach is proposed. As a result, the critical temperature, T_c, at which the zero-momentum particles disappear is determined. In the region below T_c, the temperature-dependent energy-spectrum of the quasi-particles, which has at the zero-temperature an intimate connection with that of Bogoliubov, is obtained, and the property of superfluidity which disappears at T_c is discussed. It is shown that the quasi-particles are transformed into the normal Bose particles at T_c, and the temperature-dependent energy-spectrum of the normal particles in the region above T_c is determined. It is noteworthy that the phase transition of the second-order occurs at T_c. In so far as the interaction gives the real and positive value for the energy-spectrum of both the quasi-particles and normal particles, the results above hold true, independent of the magnitude and particular shape of interaction. Some remarks are made on the hard-sphere interaction and on the interaction among the quasi-particles which seems necessary for the investigations of the intermediate-density Bose system.
理論物理学刊行会の論文
1964-04-25