Dresden 2020 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 13: Graphene (joint session TT/DY/HL)

TT 13.10: Vortrag

Montag, 16. März 2020, 17:30–17:45, HSZ 201

The optical conductivity of strongly interacting Dirac fermions: a bosonization approach to the Kadanoff-Baym self-consistent resummation — •Sebastián Mantilla and Inti Sodemann — Max Planck Institute for the Physics of Complex Systems

The optical conductivity of 2D Dirac fermions at low energies is controlled by fundamental constants of nature σ₀=e²/16 ℏ. However, Coulomb interactions produce a non-trivial dependence of the conductivity with the frequency. We use a bosonization approach to implement exactly a self-consistent Kadanoff-Baym resummation of the electron-hole propagator by mapping the momentum space lattice onto a Heisenberg-type model of interacting spins and employ this approach to determine the frequency dependence of the optical conductivity for Coulomb repulsions. We recover the perturbative renormalization group results at small coupling and extend its predictions to strong coupling. We discuss the relevance of our results to Dirac materials such as graphene and 3D topological insulator surface states.