# Dynamical scaling of charge and spin responses at a Kondo destruction quantum critical point

## TL;DR

This paper investigates the charge and spin dynamics at a Kondo destruction quantum critical point, revealing universal scaling behaviors and demonstrating that charge responses are singular and follow $/T$ scaling, consistent across models.

## Contribution

It shows that the critical exponents for spin and single-particle responses are the same as in the large-N limit, indicating subleading $1/N$ corrections, and establishes the universality of charge response scaling.

## Key findings

- Charge responses are singular and obey $/T$ scaling.
- Spin and single-particle responses share the same critical exponents as the large-N limit.
- The scaling behavior persists in the Kondo lattice model.

## Abstract

Quantum critical points often arise in metals perched at the border of an antiferromagnetic order. The recent observation of singular and dynamically scaling charge conductivity in an antiferromagnetic quantum critical heavy fermion metal implicates beyond-Landau quantum criticality. Here we study the charge and spin dynamics of a Kondo destruction quantum critical point (QCP), as realized in an SU(2)-symmetric Bose-Fermi Kondo model. We find that the critical exponents and scaling functions of the spin and single-particle responses of the QCP in the SU(2) case are essentially the same as those of the large-N limit, showing that $1/N$ corrections are subleading. Building on this insight, we demonstrate that the charge responses at the Kondo destruction QCP are singular and obey $\omega/T$ scaling. This property persists at the Kondo destruction QCP of the SU(2)-symmetric Kondo lattice model.