- Accepted Paper
ac fingerprints of 2D electron hydrodynamics: Superdiffusion and Drude weight suppression
Phys. Rev. Lett. - Accepted 21 July, 2026
DOI: https://doi.org/10.1103/p8sw-99rn
Phys. Rev. Lett. - Accepted 21 July, 2026
DOI: https://doi.org/10.1103/p8sw-99rn
Clean two-dimensional Fermi liquids are now known to exhibit an intermediate regime, between ballistic and Navier–Stokes transport, caused by the anomalously slow relaxation of parity-odd multipolar deformations of the Fermi surface. Here we show this anomaly extends to the dynamical realm. Starting from a microscopic numerical evaluation of the linearized electron–electron collision operator, we find that the finite-frequency nonlocal conductivity is controlled at low frequency by a single hydrodynamic pole, , with dynamical exponent and superdiffusive viscosity . Remarkably, the pole residue itself is scale dependent and obeys with , so the dynamical properties are described by two separate exponents rather than one. We interpret the residue suppression using a Krylov-chain description of current relaxation: as increases, the longest-lived quasinormal mode ceases to be a nearly pure current excitation and spreads over higher odd angular harmonics. Finally, we show that AC transport in narrow channels provides a direct experimental probe of these phenomena.
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