36th CEMS Colloquium


Dr. Naoto Nagaosa (RIKEN CEMS)


17:30 - 18:30, February 10, 2016 (Wednesday)


Okochi-Hall, RIKEN


Quantum geometry and topology of electronic states in solids


Since the quantum theory is formulated by rather abstract mathematics using the functional space of wavefunctions, i.e., Hilbert space, geometry is deeply involved there. In this talk, I will explain how the energy hierarchy of quantum states leads to the concept of manifolds in the Hilbert space and to the idea of gauge structures. The Berry phase is a representative example of gauge fields, which are relevant to many intriguing phenomena in solids. Various Hall effects with dissipationless currents, ferroelectricity, topological insulators, topological superconductors, Weyl semimetals, and topological solar cell action are discussed from this unified viewpoint.