Phase Separation and an Upper Bound for a Generalized Superfluid Gap for Cold Fermi Fluids in the Unitary Regime
- Department of Physics, University of Maryland, College Park, Maryland 20742-4111 (United States)
An upper bound is derived for {delta} for a cold dilute fluid of equal amounts of two species of fermion in the unitary limit k{sub f}a{yields}{infinity} (where k{sub f} is the Fermi momentum, a is the scattering length, and {delta} is a pairing energy: the difference in energy per particle between adding to the system a macroscopic number (but infinitesimal fraction) of particles of one species compared to adding equal numbers of both). The bound is {delta}{<=}(5/3)[2(2{xi}){sup 2/5}-(2{xi})] where {xi}={epsilon}/{epsilon}{sub FG}, {delta}=2{delta}/{epsilon}{sub FG}; {epsilon} is the energy per particle and {epsilon}{sub FG} is the energy per particle of a noninteracting Fermi gas. If the bound is saturated, then systems with unequal densities of the two species will separate spatially into a superfluid phase with equal numbers of the two species and a normal phase with the excess. If the bound is not saturated, then {delta} is the usual superfluid gap. If the superfluid gap exceeds the maximum allowed by the inequality, phase separation occurs.
- OSTI ID:
- 20699432
- Journal Information:
- Physical Review Letters, Vol. 95, Issue 12; Other Information: DOI: 10.1103/PhysRevLett.95.120403; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0031-9007
- Country of Publication:
- United States
- Language:
- English
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