Physical review. B, Condensed matter
Ground-state properties for ‘‘charged’’ bosons inddimensions from a renormalization-group treatment
Eugene B. Kolomeisky
Abstract
A low-density Bose system comprised of two sets of particles with different intraset and interset short-ranged interactions are studied in arbitrary space dimension d with use of a renormalization-group approach. For the range of parameters where the ground-state is nonbinding, a density expansion for the chemical potential will be given. For d2 the character of this expansion is governed by the renormalization flow to a nontrivial stable fixed point of the renormalization equations. For d>2 the expansion is governed by the flow to a trivial noninteracting fixed point and the results are expressed in the terms of two pseudopotentials. The case d=2 is marginal and is characterized by the presence of logarithmic corrections. For the range of parameters where the ground-state is binding, several different phases and corresponding phase boundaries will be located. For d\ensuremath{\le}2 we find a strong-coupling molecular phase, the constituents of which are formed from the opposite charges of the original system, and a condensed phase. For d>2 we find in addition a weak-coupling binding phase, and a strong-coupling phase with correlations characterizing a tendency to interset pairing.