Effective interaction and statistical mechanics in the pair theory of liquid helium
Abstract
The pair theory of liquid helium is discussed by assuming generalized Bose condensation. A variational method is formulated to determine the relationship between the effective interaction and the elementary excitation spectrum. The resulting system of nonlinear integral equations is solved selfconsistently to obtain the effective potential from the experimental excitation spectrum. Contrary to the previous arguments, the potential is found to be strongly repulsive for this model. The temperature dependent problem is described by means of the thermodynamically equivalent Hamiltonian method. For the potential fixed with change in temperature, the temperature dependence of the excitation spectrum is investigated. The condensate fraction at zero temperature is 50% and decreases gradually as temperature increases up to a critical point.
 Publication:

Ph.D. Thesis
 Pub Date:
 May 1974
 Bibcode:
 1974PhDT.........5Y
 Keywords:

 Liquid Helium;
 Statistical Mechanics;
 Bose Geometry;
 Elementary Excitations;
 Hamiltonian Functions;
 Quantum Statistics;
 Engineering (General)