Fermi-Fermi Mixtures in the Strong Attraction Limit

Published

January 31, 2008

Author(s)

Menderes Iskin, Carlos Sa de Melo

Abstract

The phase diagrams of low density Fermi-Fermi mixtures with equal or unequal masses and equal or unequal populations are described at zero and finite temperatures in the strong attraction limit. In this limit, the Fermi-Fermi mixture can be described by a weakly interacting Bose-Fermi mixture, where the bosons correspond to Feshbach molecules and the fermions correspond to excess atoms. First, we discuss the three- and four-fermion scattering processes, and use the exact boson-fermion and boson-boson scattering lengths to generate the phase diagrams in terms of the underlying fermion-fermion scattering length. Inthree dimensions, in addition to the normal and uniform superfluid phases, we find two stable non-uniform states corresponding to (1) phase separation between pure unpaired (excess) and pure paired fermions (molecular bosons); and (2) phase separation between pure excess fermions and a mixture of excess fermions and molecular bosons. Lastly, we also discuss the effects of the trapping potential in the density profiles of condensed and non-condensed molecular bosons, and excess fermions at zero and finite temperatures, and discuss possible implications of our findings to experiments involving mixtures of ultracold fermions.

Citation

Physical Review A (Atomic, Molecular and Optical Physics)

Volume

77

Pub Type

Journals

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Keywords

BCS-BEC crossover, Bose-Fermi mixtures, Fermi-Fermi mixtures, population imbalanced fermion mixtures

Citation

Iskin, M. and Sa, C. (2008), Fermi-Fermi Mixtures in the Strong Attraction Limit, Physical Review A (Atomic, Molecular and Optical Physics), [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=840916 (Accessed October 12, 2025)