The Physics & Astronomy Colloquium Series presents Raquel Queiroz of Columbia University, discussing "From Bonds to Correlations: Quantum Geometry in Quantum Materials" on January  30.

Abstract: Quantum geometry quantifies how electronic wavefunctions spread across a crystal, encoding the interference patterns that arise when electrons hop between orbitals. This geometric structure, captured by the quantum metric and Berry curvature, is not an abstract mathematical construct but emerges directly from chemical bonding: multi-orbital interference and lattice frustration force electrons to delocalize, imprinting geometric properties onto the electronic structure. When bands become flat, as in moiré heterostructures and frustrated lattices, kinetic energy is quenched and these geometric properties inherited from bonding become the dominant energy scale governing correlated phases.

I will show how the quantum metric sets the stiffness of superconductors and exciton condensates, stabilizes fractional Chern insulators, and determines the character of interaction-driven ground states. This perspective offers a bridge between quantum chemistry and many-body physics: the same orbital interference that defines covalent bonds ultimately controls the emergent behavior of strongly correlated electrons at low energies.