February 11 , 2009
3 pm in Howey Physics Room N110

 

Daniel P. Lathrop
University of Maryland

"Quantum turbulence"

 

Long range quantum order underlies a number of related physical phenomena including superfluidity, superconductivity, the Higgs mechanism,  Bose-Einstein condensates, and spin systems.   While superfluidity in Helium-4 was one of the earliest discovered of these, it is not the best understood, owing to the strong interactions (making theoretical progress difficult) and the lack of local experimental probes. Approximately three years ago, our group discovered that micron-sized hydrogen particles may be used to label quantized vortices in flows of superfluid helium.  Particles not on vortices trace the motion of the normal component of the superfluid. This ability has given a new perspective on an old subject. By directly observing and tracking these particles, we have directly confirmed the two-fluid model, observed vortex rings and reconnection, characterized thermal counterflows, and taken local observations of the very peculiar nature of quantum turbulence.

BIO
Daniel Lathrop is Director of the Institute for Research in Electronics and Applied Physics at the University of Maryland, and part of the Nonlinear Dynamics and Chaos group.  Dr. Lathrop received the B.A. in physics from the University of California at Berkeley in 1987, and the Ph.D. in physics from the University of Texas at Austin
in 1991. He then served at Yale University as a postdoctoral fellow, research affiliate, and lecturer.  He joined the University of Maryland in 1997, the year he received a Presidential Early Career Award from the NSF.  He is currently Professor in two departments, Physics and Geology, and in two Institutes, the Institute for Research in Electronics and Applied Physics and the Institute for Physical Sciences and Technology. In 2005, he was elected a fellow of the American Physical Society.