Quantum phase transition between one-channel and two-channel Kondo polarons

TL;DR

This paper uncovers a quantum phase transition between one-channel and two-channel Kondo screening in a mobile impurity system, supported by numerical simulations and phase diagram analysis.

Contribution

It demonstrates the existence of a novel quantum phase transition between Kondo screening regimes, combining theoretical considerations with extensive numerical evidence.

Findings

Identification of a quantum phase transition between Kondo regimes

Construction of a ground-state phase diagram

Discussion of experimental realizations

Abstract

For a mobile spin-1/2 impurity, coupled antiferromagnetically to a one-dimensional gas of fermions, perturbative ideas have been used to argue in favor of two-channel Kondo behavior of the impurity spin. Here we combine general considerations and extensive numerical simulations to show that the problem displays a novel quantum phase transition between two-channel and one-channel Kondo screening upon increasing the Kondo coupling. We construct a ground-state phase diagram and discuss the various non-trivial crossovers as well as possible experimental realizations.