PIRSA:22120024

Discrete shift and quantized charge polarization: New invariants in crystalline topological states

Manjunath, N. (2022). Discrete shift and quantized charge polarization: New invariants in crystalline topological states. Perimeter Institute. https://pirsa.org/22120024

Manjunath, Naren. Discrete shift and quantized charge polarization: New invariants in crystalline topological states. Perimeter Institute, Dec. 14, 2022, https://pirsa.org/22120024 

          @misc{ pirsa_PIRSA:22120024,
            doi = {10.48660/22120024},
            url = {https://pirsa.org/22120024},
            author = {Manjunath, Naren},
            keywords = {Condensed Matter},
            language = {en},
            title = {Discrete shift and quantized charge polarization: New invariants in crystalline topological states},
            publisher = {Perimeter Institute},
            year = {2022},
            month = {dec},
            note = {PIRSA:22120024 see, \url{https://pirsa.org}}
          }

Naren Manjunath Perimeter Institute for Theoretical Physics

DOI 10.48660/22120024
Collection
Talk Type Scientific Series
Subject

Abstract

In this talk I will describe a topological response theory that predicts the physical manifestation of a class of topological invariants in systems with crystalline symmetry. I focus on two such invariants, the 'discrete shift' and a quantized charge polarization. Guided by theory, I discuss how these invariants can be extracted from lattice models by measuring the fractional charge at lattice disclinations and dislocations, as well as from the angular and linear momentum of magnetic flux. These methods are illustrated using the Hofstadter model of spinless fermions in a background magnetic field; they give new topological invariants in this model for the first time since the quantized Hall conductance was computed by TKNN in 1982.

Zoom link:  https://pitp.zoom.us/j/93633131128?pwd=d2h4U1l0ZVU5aE1ORURkdFNSanB4dz09