Dresden 2026 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 54: Graphene: Electronic structure, excitations, etc. (joint session O/TT)

TT 54.10: Vortrag

Mittwoch, 11. März 2026, 17:15–17:30, HSZ/0204

Comparative study of plasmons in half-filled graphene via Quantum Monte Carlo and kinetic theory — Maksim Ulybyshev¹, •Adrien Reingruber¹, and Kitinan Pongsangangan² — ¹Institut für Theoretische Physik und Astrophysik, Universität Würzburg — ²Department of Physics, Faculty of Science, Mahidol University, Bangkok

A quantitative description of hydrodynamic electronic transport in strongly correlated materials requires accurate knowledge of collective excitations such as plasmons, which can notably influence viscosity. In free-standing graphene, where long-range interactions are important, standard Dirac-cone perturbation theory misses important finite Brillouin-zone and strong-coupling effects. We investigate plasmons in half-filled free-standing graphene using unbiased Quantum Monte Carlo simulations. Our results reveal well-defined plasmon peaks near the Gamma-point, map their dispersion, and extract the momentum dependence of their quasiparticle residue. Comparing to perturbative predictions, we find substantial deviations arising from the interaction and lattice effects captured only beyond the Dirac approximation. These results underscore the need to incorporate such corrections in analytical theories of electronic transport in graphene.

Keywords: plasmons; graphene; quantum monte carlo; excitations; kinetic theory