Dr. Warren Pickett
Department of Physics
Title:
Paradigm shifts and Alternative Universes in Strong coupling Superconductivity
The strong-coupling
theory of superconductivity was one of the most successful theories of real
materials behavior by the end of the 1970s; for example, the small deviations
of the temperature dependence of the critical field (the magnetic field that
destroys superconductivity) were explained very accurately. A prominent
viewpoint on higher temperature phonon-coupled superconductivity was that the
situation was clear: T_c=30 K was the most optimistic
that could be expected. Then in 2001 MgB2 was discovered to be superconducting
at 40 K. The remarkable ultra-strong coupling embodied in the MgB2 paradigm
will be described and compared to the earlier conventional wisdom. Surprising
developments in a parallel universe will be revealed publicly for the first
time