Effects of Coulomb interaction on photon-assisted current noises through a quantum dot

TL;DR

This paper investigates how Coulomb interactions influence photon-assisted current noises in a quantum dot under periodic driving, revealing the role of effective temperature and resonant structures in the noise spectra.

Contribution

It introduces a gauge-invariant approach using Floquet-Green's functions to analyze Coulomb effects on photon-assisted noise, including vertex corrections and an effective temperature concept.

Findings

Coulomb interactions suppress vertex corrections with increasing effective temperature.

Resonant structures appear in the frequency spectra of vertex corrections.

The approach enhances understanding of photon-assisted transport in interacting systems.

Abstract

We study photon-assisted transport in a single-level quantum dot system under a periodically oscillating field. Photon-assisted current noises in the presence of the Coulomb interaction are calculated based on a gauge-invariant formulation of time-dependent transport. We derive the vertex corrections within the self-consistent Hartree-Fock approximation in terms the Floquet-Green's functions (Floquet-GFs), and examine the effects of the Coulomb interaction on the photon-assisted current noises. Moreover, we introduce a concept of an effective temperature to characterize nonequilibrium properties under the influence of the AC field. The vertex corrections are suppressed by the rise of the effective temperature, whereas characteristic resonant structures appear in the frequency spectra of the vertex corrections. The present result provides a useful viewpoint for understanding photon-assisted transport in interacting electron systems.