Elementary events of electron transfer in a voltage-driven quantum point contact

TL;DR

This paper analyzes electron transfer in a voltage-driven quantum point contact, revealing that transfer events are elementary and of two types, which determine current and noise characteristics, with a formalism applicable at finite temperatures.

Contribution

It introduces a formalism that decomposes electron transfer statistics into elementary events, distinguishing unidirectional and bidirectional processes, applicable at finite temperatures.

Findings

Electron transfer consists of two elementary event types.

Unidirectional events determine average current.

Bidirectional events contribute to noise.

Abstract

We show that the statistics of electron transfer in a coherent quantum point contact driven by an arbitrary time-dependent voltage is composed of elementary events of two kinds: unidirectional one-electron transfers determining the average current and bidirectional two-electron processes contributing to the noise only. This result pertains at vanishing temperature while the extended Keldysh-Green's function formalism in use also enables the systematic calculation of the higher-order current correlators at finite temperatures.