Revealing the fuel of a quantum continuous measurement-based refrigerator

TL;DR

This paper investigates the energy exchanges in quantum measurements, demonstrating that a microscopic model is essential to distinguish heat from work, and explores a measurement-based refrigerator's efficiency trade-offs.

Contribution

It introduces a microscopic model to clarify energy exchange nature in quantum measurements and analyzes a quantum refrigerator's efficiency regimes.

Findings

Tuning measurement parameters switches between heat- and work-fueled regimes.

Maximal thermodynamic efficiency occurs in the heat-fueled regime.

Measurement efficiency is quantified by signal-to-noise ratio.

Abstract

While quantum measurements have been shown to constitute a resource for operating quantum thermal machines, the nature of the energy exchanges involved in the interaction between system and measurement apparatus is still under debate. In this work, we show that a microscopic model of the apparatus is necessary to unambiguously determine whether quantum measurements provide energy in the form of heat or work. We illustrate this result by considering a measurement-based refrigerator, made of a double quantum dot embedded in a two-terminal device, with the charge of one of the dots being continuously monitored. Tuning the parameters of the measurement device interpolates between a heat- and a work-fueled regimes with very different thermodynamic efficiency. Notably, we demonstrate a trade-off between a maximal thermodynamic efficiency when the measurement-based refrigerator is fueled by heat and a maximal measurement efficiency quantified by the signal-to-noise ratio in the work-fueled regime. Our analysis offers a new perspective on the nature of the energy exchanges occurring during a quantum measurement, paving the way for energy optimization in quantum protocols and quantum machines.