# Optimal cycles for low-dissipation heat engines

## TL;DR

This paper analyzes how to optimize finite-time Carnot engines with small dissipation, showing that small cycles around an optimal point maximize power, which scales with heat capacity, enabling efficient many-body engines.

## Contribution

It introduces a method to identify optimal cycle strategies for low-dissipation engines and demonstrates the potential for scalable many-body Carnot engines with finite power.

## Key findings

- Optimal strategy involves small cycles around a specific working point.
- Power output is proportional to the heat capacity of the working substance.
- Many-body engines can achieve maximum efficiency at finite power per constituent.

## Abstract

We consider the optimization of a finite-time Carnot engine characterized by small dissipations. We bound the power with a simple inequality and show that the optimal strategy is to perform small cycles around a given working point, which can be thus chosen optimally. Remarkably, this optimal point is independent of the figure of merit combining power and efficiency that is being maximized. Furthermore, for a general class of dynamics the power output becomes proportional to the heat capacity of the working substance. Since the heat capacity can scale supra-extensively with the number of constituents of the engine, this enables us to design optimal many-body Carnot engines reaching maximum efficiency at finite power per constituent in the thermodynamic limit.