Atomic Bose-Fermi mixed condensates with Boson-Fermion quasi-bound cluster states

TL;DR

This paper investigates the formation and role of boson-fermion bound states in mixed atomic condensates, analyzing their effects on phase structures and Bose-Einstein condensation at finite temperature and density.

Contribution

It introduces a two-body scattering model for boson-fermion pairs using a Yamaguchi potential and explores the phase diagram including composite fermions and BEC.

Findings

Composite fermion binding energy shows weak temperature dependence.

Phase diagrams reveal competition between composite fermions and BEC.

Criteria for BEC realization are derived at zero temperature.

Abstract

The boson-fermion atomic bound states (composite fermion) and their roles for the phase structures are studied in a bose-fermi mixed condensate of atomic gas in finite temperature and density. The two-body scattering equation is formulated for a boson-fermion pair in the mixed condensate with the Yamaguchi-type potential. By solving the equation, we evaluate the binding energy of a composite fermion, and show that it has small T-dependence in the physical region, because of the cancellation of the boson- and fermion- statistical factors in the equation. We also calculate the phase structure of the BF mixed condensate under the equilibrium B+F -> BF, and discuss the role of the composite fermions: the competitions between the degenerate state of the composite fermions and the Bose-Einstein condensate (BEC) of isolated bosons. The criterion for the BEC realization is obtained from the algebraically-derived phase diagrams at T=0.