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Experiments with a superfluid BEC ring

January 26, 2018 - 1:00pm
Speaker: 
Avinash Kumar
Institution: 
JQI
Abstract:
The dissertation presents multiple results of our experiments with ring-shaped $^{23}$Na Bose-Einstein condensates. First, we measure the effect of temperature on the lifetime of a quantized, persistent current. We find that the persistent current lifetime decreases when the temperature is increased. We also extract the critical velocity by measuring the size of hysteresis loops. The critical velocity is found to be a strong function of temperature. Second, we implement a new technique of measuring the circulation state of a persistent current in-situ, which is minimally-destructive. This technique uses the Doppler effect. Finally, we study the dynamics of rapidly expanding rings, and explore the analogy between our experimental system and the expansion of the universe.
 
Dissertation Committee Chair: Prof. Steven Rolston 
 
Committee: 
Dr. Gretchen Campbell (advisor)
Dr. Christopher Lobb
Dr. Charles Clark
Dr. Christopher Jarzynski
PSC 3150
College Park, MD 20742