Deformation of a trapped Fermi gas with unequal spin populations.
The real-space densities of a polarized strongly interacting two-component Fermi gas of 6Li atoms reveal two low-temperature regimes, both with a fully paired core. At the lowest temperatures, the unpolarized core deforms with increasing polarization. Sharp boundaries between the core and the excess unpaired atoms are consistent with a phase separation driven by a first-order phase transition. In contrast, at higher temperatures the core does not deform but remains unpolarized up to a critical polarization. The boundaries are not sharp in this case, indicating a partially polarized shell between the core and the unpaired atoms. The temperature dependence is consistent with a tricritical point in the phase diagram.
Partridge
G B
GB
Department of Physics and Astronomy and Rice Quantum Institute, Rice University, Houston, TX 77251, USA.
Li
Wenhui
W
Liao
Y A
YA
Hulet
R G
RG
Haque
M
M
Stoof
H T C
HT