Irreversibility on the Level of Single-Electron Tunneling

TL;DR

This paper experimentally tests the fluctuation theorem at the single-electron level in a double quantum dot, confirming theoretical predictions about entropy-consuming trajectories under nonequilibrium conditions.

Contribution

It provides the first low-temperature experimental verification of the fluctuation theorem for electron transport at the single-electron level, accounting for detection bandwidth effects.

Findings

Entropy-consuming trajectories occur with predicted frequency

Experimental results agree with theoretical fluctuation theorem

Detection bandwidth influences observed trajectory frequency

Abstract

We present a low-temperature experimental test of the fluctuation theorem for electron transport through a double quantum dot. The rare entropy-consuming system trajectories are detected in the form of single charges flowing against the source-drain bias by using time-resolved charge detection with a quantum point contact. We find that these trajectories appear with a frequency that agrees with the theoretical predictions even under strong nonequilibrium conditions, when the finite bandwidth of the charge detection is taken into account.