Quantum Institute: Visitor Schedule

The Quantum Lunch is regularly held on Thursdays in the Theoretical Division Conference Room, TA-3, Building 123, Room 121. For more information, contact Diego Dalvit, T-13.

Thursday, March 6, 2008
12:30 PM to 2 PM

Speaker: Peter Engels, Washington State University

Technical Host: Wojciech Zurek, T-DO

TOPIC: Nonlinear Dynamics in BECs ~ Faraday waves, solitons and quantum shock

Abstract
Bose-Einstein Condensates (BECs) are a powerful tool for the study of nonlinear dynamics. In our experiments we investigate nonlinear dynamics in a variety of different settings.

First, I will present our experimental demonstration of Faraday waves in a BEC. These Faraday waves are longitudinal sound waves excited by a parametric resonance. They are an important example for pattern formation in driven systems.

Second, I will discuss our observations of stable and unstable fluid flow regimes when a penetrable barrier is swept through a BEC. In the unstable regime, the generation of many solitons is observed.

Third, we investigate the merging and splitting of BECs in the nonadiabatic regime. Despite their apparent simplicity, these processes can lead to very rich dynamics. For example, we observe soliton trains as a result of quantum shock (dispersive shock) during the merging of two BECs. When a BEC is split into two parts by a repulsive barrier, a transition from sound formation to shock generation and solitons is observed with increasing barrier strength.

Finally, we observe soliton formation during the creation of a BEC when the transition from non-condensed atoms to a BEC is crossed sufficiently rapidly. This effect may be related to the Kibble-Zurek mechanism.