Regensburg 2025 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 27: Transport in Materials: Diffusion, Charge or Heat Conduction
MM 27.9: Talk
Thursday, March 20, 2025, 12:30–12:45, H22
Hydrodynamics of Lorentz symmetric systems: a quantum Monte Carlo study — •Adrien Reingruber1, Kitinan Pongsangangan2, Fakher Assaad1, and Maksim Ulybyshev1 — 1Universität Würzburg, Würzburg, Germany — 2Mahidol University, Bangkok, Thailand
We present a study on the hydrodynamic behavior of charge current in a Lorentz symmetric sys- tem: graphene at charge-neutrality. The momentum flow is completely decoupled from the charge current in this regime, since the electrons and holes propagate in opposite directions with exactly equal distribution functions. Instead of Navier-Stokes equations for the velocity field, we derive sim- ilar equations directly for the charge current. This eliminates the need for any coupling between the velocity field and charge current to explain the experimentally observed hydrodynamic flow profiles in graphene at half-filling. In this framework, the current diffusion coefficient replaces viscosity. To support this, we performed an extensive quantum Monte Carlo study, directly simulating samples with disordered edges using the underlying microscopic interacting quantum Hamiltonian. For the first time, we observe hydrodynamic behavior of the charge current in such simulations, extract- ing current profiles and a current diffusion coefficient whose temperature dependence qualitatively agrees with predictions from Boltzmann transport theory.
Keywords: Graphene; Transport; Hydrodynamics; Quantum Monte Carlo; Boltzmann theory