Title: Fulde-Ferrell super∞uid phase in an optical lattice.
Abstract: Recent developments in atomic physics like atom cooling and the use of optical lattices, equipped physicists with new tools for studding particle statistics and their interactions. It also provides the possibility to enter physical regimes that were impossible to reach until now. In this thesis we employ the effective Hubbard model for ultracold atoms in an optical lattice, a quite accurate and simple theoretical model for the regimes under consideration, in order to study the exotic superfluid Fulde-Ferrell phase. The difference in the physics of this superfluid phase is the possibility to have pairing at nonzero total momentum. In other words the Cooper pairs have a nonzero momentum. This phase transition is also important for highenergy physicists since, for example, it is believed to exist in the interior of cold compact stars. We consider an ultracold dilute Fermi gas with unequal populations for the spin up and spin down states. This situation is the analogue of a (neutral) superconductor under the influence of a Zeeman field. We start by explaining the creation of an optical lattice that is used to very accurately control the collisional properties of the atoms with the use of lasers. Next, for intuitive reasons, we study first the case of our fermi gas without an optical lattice. We then retrieve the normal to superfluid phase transition by placing our system in an optical lattice and, finally, move to the question of the existence of the Fulde-Ferrell phase.
Publication Year: 2008
Publication Date: 2008-01-01
Language: en
Type: article
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