Thermodynamics of a continuously monitored double quantum dot heat engine in the repeated interactions framework

TL;DR

This paper investigates how continuous quantum measurement affects the thermodynamics of a double quantum dot heat engine, revealing regimes where measurement stabilizes current and reduces entropy production.

Contribution

It introduces a thermodynamically consistent framework using repeated interactions to analyze measurement effects on quantum dot heat engines.

Findings

Measurement can assist and stabilize particle transport.

Continuous measurement reduces the entropic cost of driving current.

A regime exists where constant current is achieved at fixed entropy cost.

Abstract

Understanding the thermodynamic role of measurement in quantum mechanical systems is a burgeoning field of study. In this article, we study a double quantum dot (DQD) connected to two macroscopic fermionic thermal reservoirs. We assume that the DQD is continuously monitored by a quantum point contact (QPC), which serves as a charge detector. Starting from a minimalist microscopic model for the QPC and reservoirs, we show that the local master equation of the DQD can alternatively be derived in the framework of repeated interactions and that this framework guarantees a thermodynamically consistent description of the DQD and its environment (including the QPC). We analyze the effect of the measurement strength and identify a regime in which particle transport through the DQD is both assisted and stabilized by dephasing. We also find that in this regime the entropic cost of driving the particle current with fixed relative fluctuations through the DQD is reduced. We thus conclude that under continuous measurement a more constant particle current may be achieved at a fixed entropic cost.