Harnessing higher-dimensional fluctuations in an information engine

TL;DR

This paper investigates an advanced information engine that exploits higher-dimensional thermal fluctuations and feedback control to optimize energy extraction from a Brownian particle in a harmonic trap under gravity.

Contribution

It introduces a novel multi-dimensional feedback protocol that enhances engine performance by harnessing transverse thermal fluctuations, drawing parallels to the Szilard engine.

Findings

Performance improves with transverse fluctuation harnessing.

Feedback cooling of transverse degrees of freedom is effective.

Comparable results achieved without vertical measurements.

Abstract

We study the optimal performance of an information engine consisting of an overdamped Brownian bead confined in a controllable, $d$-dimensional harmonic trap and additionally subjected to gravity. The trap's center is updated dynamically via a feedback protocol designed such that no external work is done by the trap on the bead, while maximizing the extraction of gravitational potential energy and achieving directed motion. We show that performance strikingly improves when thermal fluctuations in directions perpendicular to gravity are harnessed. This improvement arises from feedback cooling of these transverse degrees of freedom, along which all heat is extracted; comparable performance can be achieved even without vertical measurements. This engine design modularizes the functions of harnessing fluctuations and storing free energy, drawing a close analogy to the Szilard engine.