Quantum Lunch Location:
T-Division Conference Room, TA-3,
Building 123, Room 121
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.
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
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
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.