Heat dissipation and fluctuations in a driven quantum dot

TL;DR

This paper investigates heat dissipation and fluctuations in a driven quantum dot system, combining experimental measurements with theoretical modeling to understand non-equilibrium thermodynamics at the nanoscale.

Contribution

It introduces a combined experimental and theoretical approach to analyze heat fluctuations and the arrow of time in a quantum dot driven far from equilibrium.

Findings

Excellent agreement between rate equation model and experiment

Quantification of heat fluctuations in a quantum dot system

Experimental validation of the arrow of time concept

Abstract

While thermodynamics is a useful tool to describe the driving of large systems close to equilibrium, fluctuations dominate the distribution of heat and work in small systems and far from equilibrium. We study the heat generated by driving a small system and change the drive parameters to analyse the transition from a drive leaving the system close to equilibrium to driving it far from equilibrium. Our system is a quantum dot in a GaAs/AlGaAs heterostructure hosting a two-dimensional electron gas. The dot is tunnel-coupled to one part of the two-dimensional electron gas acting as a heat and particle reservoir. We use standard rate equations to model the driven dot-reservoir system and find excellent agreement with the experiment. Additionally, we quantify the fluctuations by experimentally test the theoretical concept of the arrow of time, predicting our ability to distinguish whether a process goes in the forward or backward drive direction.