Speaker: Natasha Berloff
Title: Motions in a Bose Condensate.
Affiliation: UCLA.
Date: Friday, April 20, 2001.
Place and Time: Room 101 - Love Building, 3:35 pm.
Refreshments: Room 204 - Love Building, 3:00 pm.

Abstract. Quantum effects dominate the behavior of liquid helium and other Bose-Einstein condensed fluids. These effects, which include the existence of discrete quantized vortices and the quantization of hydrodynamic circulation, place severe restrictions on the types of flow that can take place in the superfluid phase. Important aspects of the behavior of the quantum vortices are still not understood. Turbulent flows in such systems are also of great interest, not only in their own right, but also because, they often appear to share important characteristics with those found in classical fluids. The recent discovery of Bose-Einstein condensation in alkali metal vapors at extremely low temperatures adds to the interest in these types of problem.
    In my talk I will use a certain form of nonlinear Schroedinger equation (NLSE) to elucidate different aspects of superfluid behavior: the motion, interactions, nucleation and reconnections of vortex lines, rings and loops; the motion of impurities; the flow through apertures; superfluid turbulence and the capture of impurities by vortex lines. I will also consider new variations of the NLSE that are more faithful to real helium II.