Non-equilibrium Fluctuation Relations in a Quantum Coherent Conductor

TL;DR

This paper experimentally validates non-equilibrium fluctuation relations in a quantum coherent conductor, confirming theoretical predictions and extending understanding of fluctuation theorems beyond classical regimes.

Contribution

First experimental demonstration of non-equilibrium fluctuation relations in a quantum coherent conductor, confirming theoretical predictions in the quantum non-linear regime.

Findings

Fluctuation theorem holds in quantum conductors under non-equilibrium conditions.

Non-equilibrium fluctuation relations are validated even when Onsager-Casmir relations are broken.

Higher order correlations between current and noise are derived from the fluctuation theorem.

Abstract

We experimentally demonstrate the validity of non-equilibrium fluctuation relations by using a quantum coherent conductor. In equilibrium the fluctuation-dissipation relation leads to the correlation between current and current noise at the conductor, namely, Johnson-Nyqusit relation. When the conductor is voltage-biased so that the non-linear regime is entered, the fluctuation theorem has predicted similar non-equilibrium fluctuation relations, which hold true even when the Onsager-Casmir relations are broken in magnetic fields. Our experiments qualitatively validate the predictions as the first evidence of this theorem in the non-equilibrium quantum regime. In the appendix, we give simple deduction of the higher order correlations between the current and the current noise based on the fluctuation theorem.