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arXiv · 2112.05076

Collinear scattering and long-lived excitations in two-dimensional electron fluids

Serhii Kryhin·Leonid Levitov
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Abstract

For a long time, it has been thought that 2D Fermi gases could support long-lived excitations, thanks to the collinear quasiparticle scattering controlled by phase space constraints at a 2D Fermi surface. We present a direct calculation that reveals such excitations. The excitation lifetimes are found to exceed the fundamental bound set by Landau Fermi-liquid theory by a factor as large as $(T_F/T)^\alpha$ with $\alpha \approx 2$. These excitations represent Fermi-surface modulations of an odd parity, one per each odd angular momentum. To explain this surprising behavior, we employ a connection between the linearized quantum kinetic equation and the dynamics of a fictitious quantum particle moving in a 1D reflectionless ${\rm sech^2}$ potential. In this framework, we identify the long-lived excitations in Fermi gases as zero modes that arise from supersymmetry.

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Serhii Kryhin, Leonid Levitov. 2021-12-09. Collinear scattering and long-lived excitations in two-dimensional electron fluids. https://doi.org/10.1103/physrevb.107.l201404

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