Quantum Metric in Superconductors and Exciton Condensates
Abstract: Superconductivity and superfluidity are some of the most striking macroscopic manifestations of quantum mechanics. In recent years strong superconductivity has been observed in systems in which the electrons behave as extremely heavy particles, i.e., have a very large effective mass. This is somewhat surprising given that the conventional theory of superconductivity predicts that the ability of a system to carry a supercurrent decreases as the effective mass of the electrons increases. In this talk I will discuss how robust superconductivity and superfluidity can be present in multi-band systems in which the effective mass of the electrons is infinite due to the quantum metric of the electronic states. This contribution is one more example of the deep connection between quantum mechanics and superconductivity. I will then discuss the relevance of this contribution for systems like twisted bilayer graphene.