The Free Electron Gas in Cavity QED

ORAL

Abstract

Cavity modification of materials is a novel research field motivated by the advances in light-matter interactions. Despite this progress, exact solutions for extended macroscopic systems strongly coupled to the photon field are not available. Therefore a paradigmatic example of an exactly solvable extended system in a cavity is highly desireable. To fill this gap we revisit Sommerfeld's theory of the free electron gas in cavity quantum electrodynamics (QED). We solve this system analytically in the long-wavelength limit and we show that the electron-photon ground state is a Fermi liquid which contains virtual photons. In contrast to models of finite systems, no ground state exists if the diamagentic A2 term is omitted. Further, the cavity field modifies the conductive properties of the electron gas. Our exact solution allows to consider the thermodynamic/continuum limit for both electrons and photons by constructing an effective quantum field theory, in which the continuum of modes leads to a many-body renormalization of the electron mass, modifies the quasiparticle excitations of the Fermi liquid, and introduces dissipation into the system.

[1] V. Rokaj, M. Ruggenthaler, F. G. Eich, A. Rubio, The Free Electron Gas in Cavity Quantum Electrodynamics, arXiv:2006.09236 (2020)

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Presenters

  • Vasil Rokaj

    • Max Planck Inst Structure & Dynamics of Matter

Authors

  • Vasil Rokaj

    • Max Planck Inst Structure & Dynamics of Matter

  • Michael Ruggenthaler

    • Max Planck Inst Structure & Dynamics of Matter
    • Theory Department, Max-Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany

  • Florian G Eich

    • Max Planck Inst Structure & Dynamics of Matter

  • Angel Rubio

    • Max Plank Institute for the Structure and Dynamics of Matter; Center for Computational Quantum Physics Flatiron Institute
    • Max Planck Institute for the Structure and Dynamics of Matter
    • Theory, Max Planck Institute for the Structure and Dynamics of Matter
    • Max Planck Inst Structure & Dynamics of Matter
    • Physics, Max Planck Institute
    • Max Planck Institute for Structure and Dynamics of Matter and Center for Free-Electron Laser Science
    • Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science, 22761 Hamburg, Germany
    • Max Planck Institute for the Structure and Dynamics of Matter and Center Free-Electron Laser Science, Hamburg, Germany
    • Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany
    • MPSD Hamburg
    • Max Planck Institute
    • Max Planck Inst Structure & Dynamics of Matter; Center for Computational Quantum Physics Flatiron Institute, Simons Foundation NY, USA
    • Theory, Max Planck Inst Structure & Dynamics of Matter