Frequency-dependent transport through a quantum dot in the Kondo regime

TL;DR

This paper investigates how frequency-dependent transport measurements can reveal the Kondo peak in a quantum dot's spectral function, using theoretical derivations and numerical simulations to connect AC conductance with equilibrium fluctuations.

Contribution

It derives a relation between spectral function and AC conductance valid at low frequencies, enabling experimental access to the Kondo resonance in quantum dots.

Findings

Frequency-dependent conductance relates to the spectral function.

Numerical simulations confirm the theoretical relation.

Method enables experimental probing of Kondo physics.

Abstract

We study the AC conductance and equilibrium current fluctuations of a Coulomb blockaded quantum dot. A relation between the equilibrium spectral function and the linear AC conductance is derived which is valid for frequencies well below the charging energy of the quantum dot. Frequency-dependent transport measurements can thus give experimental access to the Kondo peak in the equilibrium spectral function of a quantum dot. We illustrate this in detail for typical experimental parameters using the numerical renormalization group method in combination with the Kubo formalism.