Seminar
Tuesday, 12 January, 2010
Group seminar MPQ: The FFLO state in one dimensional Fermi gases
Tuesday, 12.01.2010 10 a.m. (s.t.) in Herbert-Walther-lecture room, MPQ Garching
Dr. Giuliano Orso, Theoretical Nanophysics Group, LMU
Can a Fermi gas can be superfluid if the number of up and down fermions is different? In this talk I discuss the exact answer [1] of this long standing issue for the special case of very elongated traps, where the gas can be described in terms of a 1D integrable model. I will first present the universal quantum phase diagram for a homogeneous system which is in marked contrast with its 3D counterpart. Next, I show that a 1D gas in a shallow trap phase-separates into two-shells: a partially polarized core, which is a superfluid of the FFLO type, and fully paired wings, provided the spin polarization is lower than a critical value. This theoretical prediction have now been confirmed experimentally in the group of R. Hulet at Rice University [2].
In the second part of my talk I show that the above picture can change considerably if the masses of up and down fermions are also different, due to the appearance of three-body bound states [3].
[1] G. Orso, PRL 98, 070402 (2007)
[2] Yean-an Liao et al., arXiv:0912.0092
[3] G. Orso, E. Burovski and Th. Jolicoeur, arXiv:0907.1533