Suppression of shot noise at a Kondo destruction quantum critical point

TL;DR

This paper models shot noise suppression at a Kondo destruction quantum critical point in heavy fermion metals, linking theoretical predictions with experimental observations of charge carrier behavior near quantum criticality.

Contribution

It introduces a minimal Bose-Fermi Kondo lattice model that captures Kondo destruction physics and computes shot noise suppression at the quantum critical point.

Findings

Strong shot noise suppression observed at the Kondo destruction quantum critical point

The model successfully explains experimental shot noise measurements in heavy-fermion strange metals

Provides a theoretical framework connecting quantum criticality with charge transport fluctuations

Abstract

Strange metal behavior has been observed in an expanding list of quantum materials, with heavy fermion metals serving as a prototype setting. Among the intriguing questions is the nature of charge carriers; there is an increasing recognition that the quasiparticles are lost, as captured by Kondo destruction quantum criticality. Among the recent experimental advances is the measurement of shot noise in a heavy-fermion strange metal. We are thus motivated to study current fluctuations by advancing a minimal Bose-Fermi Kondo lattice model, which admits a well-defined large-$N$ limit. Showing that the model in equilibrium captures the essential physics of Kondo destruction, we proceed to derive quantum kinetic equations and compute shot noise to the leading nontrivial order in $1/N$. Our results reveal a strong suppression of the shot noise at the Kondo destruction quantum critical point, thereby providing the understanding of the striking experiment. Broader implications of our results are discussed.