Long lifetimes of ultrahot particles in interacting Fermi systems
We investigate the energy dependence of the relaxation rate of hot electrons due to the interaction with the Fermi sea. Several setups ranging from isotropic 2D and 3D systems over quasi-1D quantum wires with multiple transverse bands to single-channel 1D wires are studied. We consider both spinful and spin-polarized setups, with short-range and Coulomb interactions. Quite generally, the relaxation rate is a non-monotonic function of the electron energy and decays as a power-law at high energies. This kind of behavior was recently observed in an experiment on multi-band quantum wires, J. Reiner et al, Phys. Rev. X 7, 021016 (2017).