Zero-frequency noise in adiabatically driven, interacting quantum systems

TL;DR

This paper studies zero-frequency noise in adiabatically driven quantum dots with interactions, revealing how Coulomb effects influence noise and how pumping noise can occur without net charge transfer.

Contribution

It introduces a real-time diagrammatic method to compute zero-frequency noise in interacting quantum systems under adiabatic driving, including effects of bias and interaction.

Findings

Adiabatic correction deviates from fluctuation-dissipation theorem due to Coulomb interactions.

Fano factor's adiabatic correction reveals coupling asymmetry, independent of pumping parameters.

Pumping noise can exist without net charge transfer when a finite bias is present.

Abstract

We investigate current-current correlations of adiabatic charge pumping through interacting quantum dots weakly coupled to reservoirs. To calculate the zero-frequency noise for a time-dependently driven system, possibly in the presence of an additional dc bias, we perform within a real-time diagrammatic approach a perturbative expansion in the tunnel coupling to the reservoirs in leading and next-to-leading order. We apply this formalism to study the adiabatic correction to the zero-frequency noise, i.e., the pumping noise, in the case of a single-level quantum dot charge pump. If no stationary bias is applied, the adiabatic correction shows Coulomb-interaction-induced deviations from the fluctuation-dissipation theorem. Furthermore, we show that the adiabatic correction to the Fano factor carries information about the coupling asymmetry and is independent of the choice of the pumping parameters. When including a time-dependent finite bias, we find that there can be pumping noise even if there is zero adiabatically pumped charge. The pumping noise also indicates the respective direction of the bias-induced current and the pumping current.