The question of understanding limits on the superconducting transition temperature Tc is of great fundamental and technological importance. I will give a pedagogical introduction to this question aimed at non-specialists. I will describe recent progress on deriving exact upper bounds on the Tc of 2D superconductors applicable to a wide range of quantum materials and to ultracold atomic gases. I will illustrate the usefulness of these bounds by making contact with recent experiments on a variety of systems where standard BCS theory fails. Next, motivated by twisted bilayer graphene, I will show how our bounds need to be generalized when the band structure exhibits non-trivial topology or lacks dispersion, i.e., flat band superconductivity. I will conclude by discussing why the question of obtaining general upper bounds on Tc in 3D remains an open challenge.
Zoom link: https://icts-res-in.zoom.us/j/95814131856?pwd=clZidGU4Yit4THBMa0YvSy9jdWw1Zz09
Meeting ID: 958 1413 1856
Passcode: 191920