Dresden 2011 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 57: Poster 3: Quantengase, Ultrakalte Atome, Ultrakalte Moleküle, Materiewellen Optik, Präzisionsmessungen, Metrologie

Q 57.5: Poster

Donnerstag, 17. März 2011, 16:30–19:30, P1

Back reaction from Bogoliubov modes onto grey solitons — •Philip Walczak and James Anglin — TU Kaiserslautern, Erwin-Schrödinger-Str. 46, 67663 Kaiserslautern

In quasi-one-dimensional Bose-condensed gases one can observe the formation of so-called grey solitons in the semi-classical limit. These are large phase and amplitude slips occurring on healing length scales. The dynamics of grey solitons is described by the non-linear Gross-Pitaevskii equation. We have found the exact solutions of the linearized problem of small excitations around a general grey soliton background. These excitations can be viewed as traveling waves in a perfectly non-reflecting potential provided by the soliton. It can be seen that asymptotically the effect of the soliton on these modes is a wave number dependent phase shift. From momentum and energy conservation one can conclude that in turn the passage of the excitations must induce a finite spatial translation the soliton. We derive an analytical expression for this classical back reaction 'dragging' effect in the case of an initial Gaussian wave packet, which is in good agreement with numerical propagation under the full non-linear equation. We discuss differences between quantum and classical back reaction.