Optimal power and efficiency of odd engines

TL;DR

This paper explores how odd materials with antisymmetric responses can be used to design engines that achieve near-perfect efficiency by applying cyclic deformations, leveraging their nonequilibrium activity.

Contribution

It introduces principles for optimizing power and efficiency in odd engines, providing strategies for designing high-performance engines based on viscoelastic materials.

Findings

Efficiency can approach unity with proper cycle design.

Strategies for optimizing power and efficiency are identified.

Guidelines for designing complex odd engines are proposed.

Abstract

Odd materials feature antisymmetric response to perturbations. This anomalous property can stem from the nonequilibrium activity of their components, which is sustained by an external energy supply. These materials open the door to designing innovative engines which extract work by applying cyclic deformations, without any equivalent in equilibrium. Here, we reveal that the efficiency of such energy conversion, from local activity to macroscopic work, can be arbitrarily close to unity when the cycles of deformation are properly designed. We illustrate these principles in some canonical viscoelastic materials, which leads us to identify strategies for optimizing power and efficiency according to material properties, and to delineate guidelines for the design of more complex odd engines.