Институт теоретической физики им. Л.Д. Ландау РАН
L.D. Landau Institute for Theoretical Physics RAS
Landau Days 2020
June, 22-25, 2020 Chernogolovka, Russia

Geometric aspects of anomalies in 3+1d Weyl systems and topological crystalline insulators
Date/Time: 11:30 25-Jun-2020
Abstract:
Topological phases have usually universally quantised transport coefficients and protected boundary modes. They arise from topological terms related by the concept of anomaly inflow from higher to lower dimensional theory. In this talk I discuss two examples of "almost topological" responses in three-dimensions, both with additional geometric fields entering the response. First, I will discuss how anomalous momentum transport in topological Weyl superfluids (and superconductors) in the presence of textures and superflow can be given a consistent interpretation as the chiral Nieh-Yan gravitational anomaly experienced by Weyl fermions on an emergent curved spacetime with torsion and curvature. The coefficient of this anomaly term is not universally quantised and seems to be determined by the underlying non-relativistic Fermi-liquid and anisotropic Galilean symmetries. Secondly, time permitting, I will discuss the three-dimensional quantum Hall effect and electric polarization in topological crystalline insulators (and semimetals) in terms of so called elasticity tetrads. We show in what sense the mixed response with elasticity tetrads and electro-magnetic fields is geometrical and topological, as well as how gauge invariance is maintained by the anomaly inflow, even in the presence of dislocations defects.

Video

Authors
Nissinen Jaakko (Presenter)
(no additional information)

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