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A: Fachverband Atomphysik

A 4: Quantum gases II (jointly with Q)

A 4.3: Gruppenbericht

Montag, 10. März 2008, 17:30–18:00, 1A

Tailoring quasi-particles in ultra-cold matter: soliton oscillations, longest lifetimes and fillings. — •Christoph Becker¹, Parvis Soltan-Panahi¹, Simon Stellmer¹, Sören Dörscher¹, Eva-Maria Richter¹, Mathis Baumert¹, Jochen Kronjäger¹, Kai Bongs^1,2, and Klaus Sengstock¹ — ¹Institut für Laser-Physik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg — ²Midlands Centre for Ultracold Atoms, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK

Solitons are distinguishing features of many non-linear physical systems. Stabilized by a balance between spreading due to dispersion and focusing mediated by non-linearities, solitons emerge as non-spreading wavepackets. BEC’s provide fascinating possibilities concerning quantum-state engineering, necessary for the creation and observation of solitons. Dark solitons appear as dips in the density distribution and have so far been produced in few experiments limited by very short lifetimes.
Here we report on the generation of dark solitons in an optically trapped ⁸⁷Rb BEC with an extraordinary life-time of up to several seconds. For the first time, we observe oscillations of dark solitons with a characteristic frequency in excellent agreement with theoretical predictions. By filling the dark soliton with atoms in another hyperfine state we are able to create dark-bright solitons with a substantially greater oscillation period.
The experimental results are combined with theoretical studies based on the Gross-Pitaevskii equation.