Dynamics in asymmetric double-well condensates

H. M. CATALDO; D. M. JEZEK

PHYSICAL REVIEW A - ATOMIC, MOLECULAR AND OPTICAL PHYSICS

AMER PHYSICAL SOC

Lugar: New York; Año: 2014 vol. 90 p. 436101 - 4361011

1050-2947

  The dynamics of Bose-Einstein condensates in asymmetric double-wells is studied. We construct a two-mode model and analyze the properties of the corresponding phase-space diagram, showing in particular that the minimum of the phase-space portrait becomes shifted from the origin as a consequence of the nonvanishing overlap between the ground and excited states from which the localized states are derived. We further incorporate effective interaction corrections in the set of two-mode model parameters. Such a formalism is applied to a recent experimentally explored system, which is confined by a toroidal trap with radial barriers forming an arbitrary angle between them. We confront the model results with Gross-Pitaevskii simulations for various angle values finding a very good agreement. We also analyze the accuracy of a previously employed simple model for moving barriers, exploring a possible improvement that could cover a wider range of trap asymmetries.       BOSE-EINSTEIN CONDENSATES IN A TOROIDAL TRAP WITH MOVING BARRIERS, D. M. Jezek and H. M. Cataldo, The 27 th International Conference on Low Temperature Physics (LT27), 6-13 August 2014, Buenos Aires, Argentina.     We study the dynamics of a BEC confined by a ring-shaped trap with two radial barriers forming an asymmetric double-well system. The barriers can move varying the angle between them. We first construct a two-mode model with a fixed angle. We show that as a direct consequence of a nonvanishing overlap between the ground and excited states, the position of the minimum in the phase diagram is shifted with respect to the symmetric case. We also introduce effective interaction energy parameters which yield a more accurate two-mode dynamics. Finally, by analyzing full Gross-Pitaevskii simulations, we show that all the set of two-mode parameters is necessary to describe the dynamics for moving barriers.     EFFECTIVE INTERACTIONS IN THE FOUR-MODE MODEL OF A TRAPPED CONDENSATE IN  THREE DIMENSIONS,   P. Capuzzi, H. M. Cataldo, and D. M. Jezek, The 27 th International Conference on Low Temperature Physics (LT27), 6-13 August 2014, Buenos Aires, Argentina.   We investigate the dynamics of a Bose-Einstein condensate confined by a four-well potential for several potential depths and number of particles. For large number of particles, it has been demonstrated that a reduced interaction energy parameter has to be taken into account to reproduce the dynamics of Bose-Einstein condensates in a four-well system within a multimode model. We find that the multi-mode dynamics is qualitatively in accordance with exact Gross-Pitaevskii simulations in three dimensions and show that the reduced interaction energy parameter may lead to accurate predictions for the dynamics in Josephson and self trapping regimes for given initial conditions.