PhD Dissertation Defense

Superfluidity in Quasi-1D Atomic Bose-Einstein Condensate

Yi Zheng
Department of Physics
University of Connecticut

Several aspects of superfluidity in an atomic Bose-Einstein Condensate are studied in a torus-type quasi-1D Model. Critical velocity of superfluid in this quasi-1D model is found. The critical velocity differs from conventional conception about the limit of velocity for frictionless flow. This result maybe one of the unique features of the quasi-1D system. For a generalized discrete quasi-1D model, the stability of Bloch oscillations is studied. Quasi-particle spectrum of small oscillations is analyzed, which in turn gives phase-diagram of stable-unstable region. The result corresponds well with a recently experimental observation. Last, we consider experiment proposals of using phase-imprinting technique to generate superfluid flow with fixed momentum or vortex in atomic BEC. Our study shows that because of back flow generated by part of imprinting potential, phase imprinting is not an ideal tool to generate a single momentum superflow or single vortex.

Wednesday, January 21, 2003
2:00 PM
Gant Science Complex
Physics Department
Room P121


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