The importance of being measurement

TL;DR

This paper examines quantum measurement engines, emphasizing the importance of detailed measurement process analysis to accurately understand energy exchanges and operational limitations in quantum thermodynamics.

Contribution

It introduces a simple model that captures the intricacies of quantum measurement, enabling a more comprehensive analysis of energy exchanges in quantum engines.

Findings

Measurement process intricacies significantly affect energy exchange calculations.

The model reveals limitations on measurement duration impacting engine performance.

Detailed analysis can improve understanding of quantum thermodynamic cycles.

Abstract

Energy exchanges under form of heat is neither the most natural or efficient way to operate an engine in the quantum realm. Recently there have been in the literature several proposals for "quantum measurement engines" where energy is fed into the machine by operations which otherwise would be conducive to quantum measurements on the working substance (henceforth "the system"). In the analysis of the working of these devices, oftentimes it is assumed that the only effect of measurement is to turn the state of the system from whatever prior state to an eigenstate of the measured property, and energy exchanges are determined therefrom. This ignores the intricacies of the quantum measurement process. We propose a simple model of a quantum measurement engine where the measurement process may be analyzed in detail, and therefore energy exchanges, and limitations on their duration, may be traced more fully.