Stuttgart 2012 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 39: Quantengase: Wechselwirkungseffekte 2

Q 39.1: Group Report

Thursday, March 15, 2012, 10:30–11:00, V7.01

Variational and full-numerical investigation of the dipolar time-dependent Gross-Pitaevskii equation — •Rüdiger Eichler, Robin Gutöhrlein, Patrick Köberle, Manuel Kreibich, Jörg Main, Günter Wunner, and Damir Zajec — 1. Institut für Theoretische Physik, Universität Stuttgart

The dynamics of dipolar Bose-Einstein condensates can be described in the mean-field limit by an extended time-dependent Gross-Pitaevskii equation.

Due to the non-local and non-linear character of the GPE for these condensates a variety of new effects occurs. We show that the wave function describing the ground state may degenerate which leads to bifurcations and exceptional points. Furthermore, we calculate Bogoliubov spectra and investigate the dynamics close to the ground state as well as beyond this linear regime. Our calculations are capable of describing the angular collapse, soliton ground states, soliton collisions, and additional effects.

Since the numerical solution of the three-dimensional GPE on a grid is a challenging task, the code has been implemented in CUDA to be run massively parallel on graphics cards. As a full-fledged alternative we use the time-dependent variational principle to obtain equations of motion for the parameters of the parametrized wave function. We show that both methods are of value in that their results support each other mutually.