# What Can We Learn from Noise? -- Mesoscopic Nonequilibrium Statistical Physics --

## TL;DR

This review explores how noise measurements in mesoscopic quantum systems can reveal fundamental insights into statistical physics, including experimental tests of fluctuation theorems in quantum regimes.

## Contribution

It highlights the role of noise as a tool for understanding quantum transport and reports the first experimental test of fluctuation theorem in a mesoscopic quantum system.

## Key findings

- Noise measurement reveals fundamental physical information.
- Experimental verification of fluctuation theorem in quantum regime.
- Insights into mesoscopic quantum statistical physics.

## Abstract

Mesoscopic systems -- small electric circuits working in quantum regime -- offer us a unique experimental stage to explorer quantum transport in a tunable and precise way. The purpose of this Review is to show how they can contribute to statistical physics. We introduce the significance of fluctuation, or equivalently noise, as noise measurement enables us to address the fundamental aspects of a physical system. The significance of the fluctuation theorem (FT) in statistical physics is noted. We explain what information can be deduced from the current noise measurement in mesoscopic systems. As an important application of the noise measurement to statistical physics, we describe our experimental work on the current and current noise in an electron interferometer, which is the first experimental test of FT in quantum regime. Our attempt will shed new light in the research field of mesoscopic quantum statistical physics.