Maxwell's lesser demon: a quantum engine driven by pointer measurements

TL;DR

This paper presents a quantum engine model driven by pointer measurements on a spin-boson system, achieving high efficiency and power in regimes where traditional quantum engines struggle, by using measurement-based feedback instead of full state access.

Contribution

It introduces a measurement-driven quantum engine utilizing pointer measurements, demonstrating high performance without requiring full quantum state control or Landauer's erasure.

Findings

Engine reaches power and efficiency benchmarks

Operates effectively in regimes where quantum Otto engines fail

Uses pointer measurements for feedback control

Abstract

We discuss a self-contained spin-boson model for a measurement-driven engine, in which a demon generates work from thermal excitations of a quantum spin via measurement and feedback control. Instead of granting it full direct access to the spin state and to Landauer's erasure strokes for optimal performance, we restrict this demon's action to pointer measurements, i.e. random or continuous interrogations of a damped mechanical oscillator that assumes macroscopically distinct positions depending on the spin state. The engine can reach simultaneously the power and efficiency benchmarks and operate in temperature regimes where quantum Otto engines would fail.