SOME ASPECTS OF CORRELATION IN MANY-PARTICLE SYSTEMS.
Miller, Allen
In the formulation of the theory of the interacting many-boson system, the sign of the Fourier Transform of the two-particle interaction in the limit of long-wavelengths plays a dominant role in determining the character of the theory. With this in mind, we have obtained the following result: If the interaction between two neutral atoms is considered in the adiabatic approximation, and if the electronic wave functions correspond to the lowest energy state, then the sign of the scattering length will be negative. For the case of negative scattering lengths, an expansion is given for the ground-state energy of a system of interacting Bose particles. The expansion is performed in a way that eliminates the third-order divergence which results when the entire interaction is used as the perturbation. The structure factor, computed to first order, is in qualitative agreement with experiment, for large momentum values. For non-zero temperatures, expressions are obtained for the depletion of the zero-momentum mode and the specific heat. The results for the specific heat exhibit a discontinuity at the critical temperature. Quantitative estimates for the magnitude of the specific heat at the critical point yield results which are in fair agreement with empirical values for liquid helium. (Author)
•May 1, 1965•0 citations