Quantum measurement engines and their relevance for quantum interpretations

TL;DR

This paper reviews recent advances in quantum measurement engines, introduces new designs, and explores their implications for quantum interpretations and the fundamental understanding of quantum measurement and energy extraction.

Contribution

It presents novel quantum measurement engine designs and analyzes their efficiency, work extraction, and philosophical implications for quantum theory.

Findings

A feedback-based atom-and-piston engine links work to successful events.

An unconditional, coherent qubit engine can achieve perfect efficiency.

Quantum measurements that do not commute with the Hamiltonian necessarily alter the system's energy.

Abstract

This article presents recent progress in the theory of quantum measurement engines and discusses the implications of them for quantum interpretations and philosophical implications of the theory. Several new measurement engine designs are introduced and analyzed: We discuss a feedback based atom-and-piston engine that sharply associates all work with successful events and all quantum heat with the failed events, as well as an unconditional but coherent qubit engine that can attain perfect efficiency. Any quantum measurement of an observable that does not commute with the Hamiltonian will necessarily change the energy of the system. We discuss different ways to extract that energy, the efficiency and work production of that process.