Back-action Induced Non-equilibrium Effect in Electron Charge Counting Statistics

TL;DR

This study investigates how back-action from a quantum point contact influences charge counting statistics in a quantum dot, revealing tunable non-equilibrium effects and the roles of coupling and bias voltage.

Contribution

It demonstrates controlled back-action effects on quantum dot charge statistics and quantifies the induced non-thermal saturation phenomena.

Findings

Back-action causes tunable non-thermal saturation in charge statistics.

QPC bias and coupling influence back-action strength and energy cut-off.

Quantitative characterization of back-action induced tunneling rates.

Abstract

We report our study of the real-time charge counting statistics measured by a quantum point contact (QPC) coupled to a single quantum dot (QD) under different back-action strength. By tuning the QD-QPC coupling or QPC bias, we controlled the QPC back-action which drives the QD electrons out of thermal equilibrium. The random telegraph signal (RTS) statistics showed strong and tunable non-thermal-equilibrium saturation effect, which can be quantitatively characterized as a back-action induced tunneling out rate. We found that the QD-QPC coupling and QPC bias voltage played different roles on the back-action strength and cut-off energy.