Canceled: Raquel Pinheiro de Almeida Queiroz: Ring States in Topological Matter

Abstract:

Topological obstructions in quantum matter prevent the construction of symmetric and exponentially localized Wannier states from Bloch bands. We show that a topological obstruction leads to bound states at finite ingap energies for local symmetric potentials that exceed the Bloch Hamiltonian's bandwidth, such as lattice vacancies. The resulting ingap states, which we call ring states, are the precursors of topological boundary modes and can serve as a local probe of topology. We demonstrate the origin of ring states as well as boundary states from the pole structure of the local Green's function, present in topological phases protected by internal or spatial symmetries.

Bio: 

Raquel Queiroz is an Assistant Professor of Physics at Columbia University. Her group studies how the behavior of materials is determined by the geometric properties of quantum states. She obtained her undergraduate degrees in Physics at the University of Lisbon, Instituto Superior Tecnico, in 2009; her M.A. at Imperial College London in 2010; and her Ph.D. at the Max Planck Institute for Solid State Research in 2015. Her postdoctoral work was at the Weizmann Institute of Science in Rehovot, Israel, where she received the Feinberg prize for outstanding achievements.