Local quantum critical point in the pseudogap Anderson model: finite-T dynamics and omega/T scaling

TL;DR

This paper investigates the finite-temperature dynamics of the pseudogap Anderson model near its quantum critical point, revealing omega/T scaling and detailed spectral behavior at criticality.

Contribution

It provides an analytical study of the scaling spectra and finite-temperature dynamics near the quantum critical point in the pseudogap Anderson model.

Findings

omega/T scaling at the quantum critical point

Collapse of the Kondo resonance at criticality

Analytical expressions for spectral functions in different phases

Abstract

The pseudogap Anderson impurity model is a paradigm for locally critical quantum phase transitions. Within the framework of the local moment approach we study its finite-T dynamics, as embodied in the single-particle spectrum, in the vicinity of the symmetric quantum critical point (QCP) separating generalized Fermi-liquid (Kondo screened) and local moment phases. The scaling spectra in both phases, and at the QCP itself, are obtained analytically. A key result is that pure omega/T-scaling obtains at the QCP, where the Kondo resonance has just collapsed. The connection between the scaling spectra in either phase and that at the QCP is explored in detail.