Double quantum dot as a probe of nonequilibrium charge fluctuations at the quantum point contact

TL;DR

This paper investigates how a double quantum dot can be used to probe nonequilibrium charge fluctuations at a quantum point contact by analyzing the inelastic current influenced by the contact's transmission properties.

Contribution

It introduces a theoretical framework for understanding inelastic current in a double quantum dot as a probe of quantum point contact fluctuations, highlighting differences from single quantum dot systems.

Findings

Inelastic current depends on the energy dependence of QPC transmission.

The model explains experimentally observed features.

Calculated inelastic current as a function of circuit parameters.

Abstract

Absorption of energy quanta generated by quantum point contact results in the inelastic current through the double quantum dot placed nearby. In contrast to a single quantum dot, the inelastic current through the double quantum dot is sensitive to the energy dependence of the quantum point contact transmission, which can explain the experimentally observed features. We calculate the inelastic current as a function of microscopic parameters of the circuit.