Asymmetric two-component fermion systems in strong coupling
Mar, 20054 pages
Published in:
- Phys.Rev.Lett. 95 (2005) 060401
e-Print:
- cond-mat/0503256 [cond-mat]
Report number:
- LA-UR-05-1389
View in:
Citations per year
Abstract: (arXiv)
We study the phase structure of a dilute two-component Fermi system with attractive interactions as a function of the coupling and the polarization or number difference between the two components. In weak coupling, a finite number asymmetry results in phase separation. A mixed phase containing symmetric superfluid matter and an asymmetric normal phase is favored. With increasing coupling strength, we show that the stress on the superfluid phase to accommodate a number asymmetry increases. Near the infinite-scattering length limit, we calculate the single-particle excitation spectrum and the ground-state energy at various polarizations. A picture of weakly-interacting quasi-particles emerges for modest polarizations. In this regime near infinite scattering length, and for modest polarizations, a homogeneous phase with a finite population of excited quasi-particle states characterized by a gapless spectrum should be favored over the phase separated state. These states may be realized in cold atom experiments.- 25.75.Nq
- 74.20.Fg
- 21.65.+f
- 03.75.Ss
- fermion systems
- phase separation
- quasiparticles
- superfluidity
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