The χ-ensemble formulation of Lee and Yang is used as the basis for a theory of the degenerate Bose fluid. The expansions of the grand potential and the momentum distribution are rearranged through a set of simple transformations; the transformed expansions no longer contain free particle...

The theory developed in an earlier paper is applied to the degenerate Bose fluid at very low temperatures. It is seen that the transformation functions A(k), B(k), and C(k) can be chosen in such a way that the expansions of the grand potential and the momentum distribution are well-behaved at...