Physics (Internal)

Particle-hole symmetric phases in multicomponent Landau levels

This event is part of the Condensed Matter Theory Seminar Series.

Abstract: The picture of fractional quantum Hall states as liquids of composite particles made from electrons bound to fluxes has evolved over the years as a central paradigm in the understanding of these phases. A recent proposal on the compressible phase that arises in half-filled Landau levels allows to consistently incorporate the particle-hole symmetry by viewing the composite fermion as a Dirac particle. In turn, the natural habitat for this Dirac composite fermion is the surface of a chiral topological insulator protected by an anti-unitary particle-hole symmetry with a single Dirac cone. In this talk I will describe generalizations of these ideas to the case of N-component landau levels, such as those arising in quantum Hall bilayers (N=2) and graphene (N=4). When multi-component Landau levels are half filled they can be viewed as the surface of a chiral topological insulator with N Dirac cones. I will describe gapped phases that respect the particle-hole symmetry and are topologically ordered and discuss their potential experimental realization.