Nonequilibrium Transport through Double Quantum Dots: Exact Results near Quantum Critical Point

TL;DR

This paper analyzes the nonequilibrium transport properties of a double quantum dot system modeled by the 2-impurity Kondo model near its quantum critical point, providing exact results for conductance scaling.

Contribution

It derives a universal scaling function for finite temperature nonlinear conductance near the quantum critical point, including potential scattering effects.

Findings

Universal conductance scaling function predicted

Exact results for crossover behavior obtained

Non-Fermi liquid fixed point characterized

Abstract

We study a double quantum dot in the regime where each dot carries a spin-1/2. This system is described by the 2-impurity Kondo model, having a non-Fermi liquid fixed point for a critical value of the inter-impurity coupling. The Hamiltonian describing the vicinity of the critical point, including the relevant potential scattering perturbations, can be cast in quadratic form. This allows us to predict a universal scaling function for the finite temperature nonlinear conductance along the crossover from the critical point to the surrounding stable fixed points.