Directed Transport in BOSE-EINSTEIN Condensates

Abstract

The thesis deals with the phenomenon of directed transport in Bose-Einstein condensates (BECs). At first an explanation of what a BEC is and what directed transport means is provided while motivating the interest of the work. Two different experimental set-ups for the confinement of a BEC have been considered: (i) a quasi-1D torus-like trap and a quasi 1-D cigar-like trap. Also two experimentally feasible different kind of external asymmetric driving potential have been analyzed: (i) kicked potentials and (ii) smoothly time-changing driving potentials. In the first part a model in which a non-interacting BEC presents a, classically unexpected, directed acceleration is studied. In the following it is shown, in two different models, how directed currents can emerge as a result of atom-atom interaction in the BEC. Last we have shown how BEC solitons respond to an asymmetric, directed current generating, driving potential.