Colloquium: The theory of superconductivity remains a challenge after 100 years of its discovery

Sumit Mazumdar, University of Arizona
Friday, February 24, 2017 - 3:00pm
PAS 220

More than three decades after John Bardeen, Leon Cooper and J. Robert Schrieffer (BCS) were awarded the Nobel Prize in physics for their 1957 theory of superconductivity, and following four other Nobel Prizes to superconductivity researchers, superconductivity continues to be an enigma. The fundamental reason for this is that the BCS theory assumes that transition to the superconducting state occurs from a state with perfect symmetry, viz., a metal (electron-gas). In contrast, multiple broken symmetries compete or coexist in today's correlated-electron superconductors, and transition to the superconductor is from an unconventional semiconductor, not a metal at all! I will discuss our recent progress in this area, introducing the concept of the paired Wigner crystal. All other relevant concepts of broken symmetries will be introduced in the talk, and no knowledge of condensed matter physics beyond graduate quantum mechanics will be assumed. The talk will be (almost) purely theoretical with little to no reference to the background materials science.