MATHEMATICS COLLOQUIUM
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.
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