Speaker
Dr
Antun Balaz
(Institute of Physics Belgrade)
Description
In this talk we will present our recent results of the study of ultracold quantum gases, obtained using the NUQG high-performance computing application developed in the framework of HP-SEE project. First, by extensive numerical simulations of the underlying Gross-Pitaevskii equation [1], we will show how parametric excitation of Bose-Einstein condensed systems can lead to formation of Faraday patterns [2]. For two-component systems we will show that the excited Faraday waves far from resonances are of similar periods, emerge simultaneously, and do not impact the dynamics of the bulk of the condensate. We will also show that for a modulation frequency close to twice that of the radial trapping, the emergent surface waves fade out in favor of a forceful collective mode that turns the two condensate components miscible. Second, we will investigate effects of the geometry of the trap to the behavior of Bose-Einstein condensates [3,4]. By changing the anisotropy of the confining potential, we numerically observe strong nonlinear effects: shifts in the frequencies and mode coupling of collective modes [5], as well as geometric resonances. Finally, motivated by recent experimental results on the dynamics of a cigar-shaped Bose-Einstein condensate subject to periodic modulation of the scattering length, we investigate the dynamics of the condensate and show that for resonant drives of large amplitude the condensate reaches a fragmented state. The fragmented state is a mixture of a quadrupole collective oscillation mode on top of which a longitudinal resonant density wave is grafted.
[1] D. Vudragović, I. Vidanović, A. Balaž, P. Muruganandam, and S. K. Adhikari, Comp. Phys. Commun. 183, 2021 (2012).
[2] A. Balaž and A. I. Nicolin, Phys. Rev. A 85, 023613 (2012).
[3] I. Vidanović, H. Al-Jibbouri, A. Balaž, and A. Pelster, Phys. Scr. T149, 014003 (2012).
[4] H. Al-Jibbouri, I. Vidanović, A. Balaž, and A. Pelster, arXiv:1208.0991 (2012).
[5] I. Vidanović, A. Balaž, H. Al-Jibbouri, and A. Pelster, Phys. Rev. A 84, 013618 (2011).
Primary author
Dr
Antun Balaz
(Institute of Physics Belgrade)
Co-authors
Dr
Alexandru Nicolin
(Horia Hulubei National Institute for Physics and Nuclear Engineering)
Dr
Axel Pelster
(Technical University of Kaiserslautern)
Mr
Dusan Vudragovic
(Institute of Physics Belgrade)
Mr
Hamid Al-Jibbouri
(Free University of Berlin)
Dr
Ivana Vidanovic
(Institute of Physics Belgrade)
