Non-reciprocal Quantum Matter: Quantum Geometry and Kramers Degeneracy

Explore the fascinating world of non-reciprocal quantum matter in this comprehensive lecture by Justin Song from PCS Institute for Basic Science. Delve into a field-free, "non-classical" paradigm that leverages the intricate winding of electronic wavefunctions in quantum materials, focusing on topology and quantum geometry. Discover how quantum geometry enables a range of non-reciprocal phenomena in both linear and nonlinear regimes, including non-reciprocal collective modes like plasmons and nonlinearities dependent on Kramers degeneracy in PT antiferromagnets. Investigate the extreme limit of nonlinearities and their potential to create self-sustained phases with properties markedly different from equilibrium states. Learn about the unusual "layer electric phase" in layered matter such as centrosymmetric multilayer graphene, and understand how nonequilibrium photoexcitation can transform dielectric screening into anti-screening, overscreening, and ferro-electric like polarizations. Gain insights into the potential applications of these phenomena for controlling electric polarization in layered materials and creating out-of-equilibrium dynamical quantum matter.