English

BEC-BCS crossover in "magnetized" Feshbach-resonantly paired superfluids

Superconductivity 2009-11-11 v3 Statistical Mechanics

Abstract

We map out the detuning-magnetization phase diagram for a ``magnetized'' (unequal number of atoms in two pairing hyperfine states) gas of fermionic atoms interacting via an s-wave Feshbach resonance (FR). For large positive FR detuning a normal magnetized Fermi gas is stable above an exponentially small value of the population difference. Below this critical value the phase diagram is dominated by coexistence of a magnetized normal gas and a singlet paired superfluid with the latter exhibiting a BCS-Bose Einstein condensate crossover with reduced detuning. On the BCS side of strongly overlapping Cooper pairs, a sliver of finite-momentum paired Fulde-Ferrell-Larkin-Ovchinnikov magnetized phase intervenes between the phase separated and normal states. In contrast, for large negative detuning a uniform, polarized superfluid, that is a coherent mixture of singlet Bose-Einstein-condensed molecules and fully magnetized single-species Fermi-sea, is a stable ground state.

Keywords

Cite

@article{arxiv.cond-mat/0508430,
  title  = {BEC-BCS crossover in "magnetized" Feshbach-resonantly paired superfluids},
  author = {Daniel E. Sheehy and Leo Radzihovsky},
  journal= {arXiv preprint arXiv:cond-mat/0508430},
  year   = {2009}
}

Comments

4 RevTeX pages, 2 figures. Minor changes from previous version