Heidelberg 2015 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 15: Poster: Quantum Optics and Photonics I

Q 15.6: Poster

Montag, 23. März 2015, 17:00–19:00, C/Foyer

Expansion dynamics of dual-species Bose-Einstein condensates computed with co-moving grids — •Matthias Meister, Albert Roura, Wolfgang P. Schleich, and the QUANTUS Team — Institut für Quantenphysik, Universität Ulm

In recent years simultaneous Bose-Einstein condensation of different atomic species has been realized for a growing variety of mixtures. Hence, it is essential to develop new tools for a better theoretical understanding of these systems.

We present a numerical method for computing the ground state of a dual-species Bose-Einstein condensate and studying its expansion dynamics for arbitrarily long times after release from the trap. Our implementation builds upon ideas of ref. [1], which rely on performing a transformation to co-moving coordinates according to the scaling approach [2] instead of using a static grid in the lab frame. As a result we are left with a system that shows nearly no dynamics because the main contribution due to the expansion is encoded in the transformation. Thus, our simulations are not limited by the expansion time since the size of the condensate stays almost constant in the co-moving frame. Also, the remaining time evolution can be computed efficiently with only a few grid points as the wave functions are very smooth.

[1] M. Eckart, Non-equilibrium dynamics of trapped gases in controlled geometries, Ph.D. thesis, Universität Ulm, Ulm (2008)

[2] Y. Castin and R. Dum, Phys. Rev. Lett. 77, 5315 (1996); Y. Kagan, E. L. Surkov and G. V. Shlyapnikov, Phys. Rev. A 54, R1753 (1996) and Phys. Rev. A 55, R18 (1997)