Solid State & Optics Seminar
sponsored by “The Flint Fund Series on Quantum Devices and Nanostructures”
Date : Wednesday, 4/26/23
Time: 1:00 PM
Prof. Kathy Levin, University of Chicago
Location: Mason 107 or Via Zoom
Zoom Link: https://yale.zoom.us/j/98481828038?pwd=MjNHNUdvdjNON044cTRWZFVYL3FJQT09
Password: 388823
WHEN SUPERCONDUCTIVITY CROSSES OVER: FROM BCS TO BEC
Motivated by the recent observations of ultra-strong pairing in the
twisted graphene family, this talk will explain in some detail how to
think about the crossover of BCS to Bose Einstein condensation (BEC)
superconductivity found in the solid state: what it is and what it is
not. This crossover superconductivity in solids is, in many ways,
crucially different from its counterpart observed in atomic physics
laboratories where Fermi gas superfluids are widely studied. An
interesting controversy surrounds the relation of crossover
superconductivity to BCS theory, dating back to Bardeen, then to
P. Nozieres as well as others. Besides twisted graphene we address other
recently discovered BCS-BEC crossover candidate materials including
surprisingly high- Tc- superconductivity found in single unit cell films
of Fe-Se and the more well known, but still not understood,
superconductivity in the cuprates.