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    COLLOQUIUM OF THE LABORATORY FOR COMPUTER DESIGN OF MATERIALS
        Institute for Computational Sciences and Informatics
	                      CSI 898-Sec 001  
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             Vortex States and Unconventional Superconductivity 
                             Daryl W. Hess
 Complex Systems Theory Branch, Naval Research Laboratory, Washington, DC

The discovery of the complicated field-temperature phase diagram of 
the heavy-fermion superconductor UPt_3, together with pioneering STM 
experiments that image vortex cores, has opened a new frontier in the 
study of unconventional superconductivity.  The order parameter of 
an unconventional superconductor often has more degrees of freedom 
than that of a conventional superconductor, leading to the 
possibility of additional superconducting phases in the vortex core. 
This is evident in the vortex solutions of  Ginzburg-Landau (GL) 
equations for candidate unconventional superconducting states for 
UPt_3.  These also illustrate how broken symmetry in the crystal 
lattice can be reflected in the structure of the vortex core.  
Important to technological applications that would exploit 
unconventional superconductivity are the quasiparticles ignored 
in a GL theory.  I will discuss vortex solutions for UPt_3 in the 
quasiclassical theory and show consequences of broken time-reversal 
symmetry on the quasiparticle states in the vortex core.

	               Monday , November 17 1997
                                 4:30 pm
                        Room 206, Science & Tech. I

Refreshments will be served.
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(http://www.csi.gmu.edu/lcdm/seminar/schedule.html)