Bounds on the Superconducting Transition Temperature

Speaker: Mohit Randeria (The Ohio State University, USA, & Indian Institute of Science, Bengaluru, India)

Date and time


Superconductivity is a striking phenomenon in which a system exhibits zero electrical resistance for temperatures below the transition temperature Tc. The question of understanding quantum mechanical limits on Tc is thus one of great fundamental and technological importance.

I will start with a detailed pedagogical introduction for 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 experiments on a variety of systems where standard BCS theory fails. Next, 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 obtaining general upper bounds on Tc in 3D remains an open challenge.

Mohit Randeria

Mohit Randeria is Professor of Physics at The Ohio State University and currently an Infosys Visiting Chair Professor at IISc Bengaluru. His research focuses on quantum materials and condensed matter theory. He obtained a BTech in electrical engineering from IIT Delhi, MS from Caltech, and PhD in theoretical physics from Cornell. After post-doctoral research at the University of Illinois at Urbana-Champaign, he taught at Stony Brook, was on the staff of Argonne National Labs, and on the faculty of the Tata Institute of Fundamental Research, before moving to Ohio State in 2004. He has held visiting professorships at Urbana-Champaign, Berkeley, MIT and Harvard. He is a winner of the Bhatnagar Award, the ICTP Prize, the IIT Delhi Distinguished Alumni Award, and is a Fellow of the American Physical Society and the American Association for the Advancement of Science. He was awarded the 2022 John Bardeen Prize for his work on superconductivity. For more information on his research see: