Guojun Zhu, Anthony J. Leggett
We consider the behavior of an ultracold Fermi gas across a narrow Feshbach
resonance, where the occupation of the closed channel may not be negligible.
While the corrections to the single-channel formulae associated with the
nonzero chemical potential and with particle conservation have been considered
in the existing literature, there is a further effect which to the best of our
knowledge has until now escaped attention, namely the "inter-channel Pauli
exclusion principle" associated with the fact that a single hyperfine species
may be common to the two channels. We focus on this effect and show that, as
intuitively expected, the resulting corrections are of order $E_F/\eta$, where
$E_F$ is the Fermi energy of the gas in the absence of interactions and $\eta$
is the Zeeman energy difference between the two channels. We also consider the
related corrections to the fermionic excitation spectrum, and briefly discuss
the collective modes of the system.
View original:
http://arxiv.org/abs/1202.4547
No comments:
Post a Comment