The structure of quasiparticles in a local Fermi liquid

Abstract

Conduction electrons interacting with a dynamic impurity can give rise to a local Fermi liquid. The latter has the same low energy spectrum as an ideal Fermi gas containing a static impurity. The Fermi liquids's elementary excitations are however not bare electrons. In the vicinity of the impurity, they are dressed by virtual particle-hole pairs. Here we study this dressing. Among other things, we construct a mode-resolved measure of dressing. To evaluate it in position representation, we have to circumvent the limitations of the Numerical Renormalization Group, which discretizes the conduction band logarithmically. We therefore extend Natural Orbital methods, that successfully characterize the ground state, to describe excitations. We demonstrate that the dressing profile shows nontrivial powerlaw decay at large distances. Our Natural Orbital methodology could lay the foundation for calculating the properties of local Fermi liquid quasiparticles in nontrivial geometries such as disordered hosts or mesoscopic devices.