The Two-Impurity Anderson Model at Quantum Criticality

TL;DR

This paper models a double quantum-dot system to explore a quantum phase transition characterized by non-Fermi liquid behavior, using conformal field theory to analyze critical exponents and dynamical properties.

Contribution

It provides a theoretical realization of the two-impurity Anderson model at quantum criticality and identifies key scaling and dynamical exponents using conformal field theory.

Findings

Identification of a quantum phase transition controlled by non-Fermi liquid fixed points

Determination of scaling exponents for transport and thermodynamics near criticality

Calculation of dynamical exponents for non-Fermi liquid state buildup

Abstract

We propose a realization of the two-impurity Anderson model in a double quantum-dot device. When charge transfer between the dots is suppressed the system exhibits a quantum phase transition, controlled by a surface of non-Fermi liquid fixed points parameterized by the charge valences of the dots. Employing conformal field theory techniques, we identify the scaling exponents that govern transport and thermodynamics close to criticality. We also determine the dynamical exponents that set the time scale for buildup of the non-Fermi liquid state after the system is suddenly shifted into the critical region, e.g. by a change of a nearby gate voltage.