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Condensed Matter Seminar: "Topology of the Fermi Sea"

Event Type
Physics - Condensed Matter
190 ESB
Apr 15, 2022   1:00 pm  
Charlie Kane, University of Pennsylvania
Originating Calendar
Physics - Condensed Matter Seminar

The Fermi sea in a metal is a topological object characterized by an integer topological invariant called the Euler characteristic, cF.  In this talk we will argue that for a 2D fermi gas cF is reflected in a quantized frequency dependent non-linear 3 terminal conductance that generalizes the Landauer conductance in D=1.  We will critically address the roles of electrical contacts and Fermi liquid interactions, and we will propose experiments on 2D Dirac materials, such as graphene, using a triple point contact geometry.   We will go on to show that for a D dimensional Fermi gas, cF is also reflected in the multipartite entanglement characterizing D+1 regions that meet at a point.  This generalizes a well-known result that relates the bipartite entanglement entropy of a 1+1D conformal field theory to its central charge c.   We will argue that for an interacting 3D Fermi liquid, cF distinguishes distinct topological Fermi liquid phases.

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