Title: "Quantum Geometry in Flat Bands"
Abstract: By endowing the Hilbert space with a metric and a curvature, the modern theory of solids resorts to tools from differential geometry and topology to analyze the physical properties of electrons in a crystal. After introducing the concept of the quantum geometric tensor, I will explore implications of the quantum geometry in flat bands, where the quasiparticles have zero group velocity. I will then address the possibility of using pumped light in flat Chern bands to create out-of-equilibrium excitons with finite vorticity in momentum space. Those excitons, called topological excitons, have their vorticity set by the difference between the Chern numbers in the conduction and valence bands. Topological excitons can be found optically through the non-linear Hall effect and can condense into a novel type of topological neutral superfluid.
Zoom Link: https://illinois.zoom.us/my/icmt.seminar?pwd=ZU1KbnBLeXZLUmJKc0oyU205cDNDdz09
Meeting ID: 791 382 8328
Password: 106237