Detector-induced backaction on the counting statistics of a double quantum dot

TL;DR

This paper studies how a quantum point contact detector influences the counting statistics of electron transport in a double quantum dot, revealing that backaction can significantly alter noise and skewness characteristics.

Contribution

It demonstrates the profound effects of detector-induced backaction on counting statistics, including changes in shot noise and skewness, in a double quantum dot system.

Findings

Backaction can switch shot noise from sub-Poissonian to super-Poissonian.

Backaction can change skewness from positive to negative.

Energy difference affects Fano factor and skewness under backaction.

Abstract

Full counting statistics of electron transport is of fundamental importance for a deeper understanding of the underlying physical processes in quantum transport in nanoscale devices. The backaction effect from a detector on the nanoscale devices is also essential due to its inevitable presence in experiments. Here we investigate the backaction of a charge detector in the form of a quantum point contact (QPC) on the counting statistics of a biased double quantum dot (DQD). We show that this inevitable QPC-induced backaction can have profound effects on the counting statistics under certain conditions, e.g., changing the shot noise from being sub-Poissonian to super-Poissonian, and changing the skewness from being positive to negative. Also, we show that both Fano factor and skewness can be either enhanced or suppressed by increasing the energy difference between two single-dot levels of the DQD under the detector-induced backaction.