SKM 2023 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 65: Correlated Electrons: Other Theoretical Topics

TT 65.2: Talk

Friday, March 31, 2023, 09:45–10:00, HSZ 204

Non-Fermi-liquid behavior from critical electromagnetic vacuum fluctuations — •Peng Rao and Francesco Piazza — Max Planck Institute for the Physics of Complex Systems, Dresden, Germany

We study two-dimensional materials where electrons are coupled to the vacuum electromagnetic field of a cavity. We show that, at the onset of the superradiant phase transition towards a macroscopic photon occupation of the cavity, the critical electromagnetic fluctuations, consisting of photons strongly overdamped by their interaction with electrons, can in turn lead to the absence of electronic quasiparticles. Since transverse photons couple to the electronic current, the appearance of non-Fermi-Liquid behavior strongly depends on the lattice. In particular, we find that in a square lattice the phase space for electron-photon scattering is reduced in such a way to preserve the quasiparticles, while in a honeycomb lattice the latter are removed due to a non-analytical frequency dependence of the damping ∝ |ω|^2/3. Standard cavity probes could allow to measure the characteristic frequency spectrum of the overdamped critical electromagnetic modes responsible for the non-Fermi-liquid behavior.