Hannover 2010 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 55: Poster II

Q 55.3: Poster

Thursday, March 11, 2010, 16:00–19:00, Lichthof

Quantum brownian motion of grey solitons in 1D-condensates — •Philip Walczak and James R. Anglin — Fachbereich Physik, TU Kaiserslautern, D-67663 Kaiserslautern

In interferometry experiments with quasi-one-dimensional Bose-condensed gases [1] one can observe local shifts in the interference pattern which are due to thermal phase fluctuations of the condensates. In the semi-classical limit, large phase slips can occur on healing length scales through the formation of so-called grey solitons. Using a path integral with canonical collective co-ordinates for a grey soliton, we compute probabilities for phase slips as quantum and thermal fluctuations. We incorporate Brownian motion of the soliton due to back reaction on the soliton co-ordinates from the Bogoliubov modes of the quasi-one-dimensional dilute Bose gas. The derivation of the soliton collective co-ordinates is illustrated with a two dimensional example.

[1] J. Schmiedmayer et al., Nature 449, 324-328 (2007)