We demonstrate how to incorporate a catalyst to enhance the performance of a heat engine. Specifically, we analyze efficiency in one of the simplest engine models, which operates in only two strokes and comprises of a pair of two-level systems, potentially assisted by a $d$-dimensional catalyst. When no catalysis is present, the efficiency of the machine is given by the Otto efficiency. Introducing the catalyst allows for constructing a protocol which overcomes this bound, while new efficiency can be expressed in a simple form as a generalization of Otto’s formula: $1-(1/d)({\omega }_c/{\omega }_h)$. The catalyst also provides a bigger operational range of parameters in which the machine works as an engine. Although an increase in engine efficiency is mostly accompanied by a decrease in work production (approaching zero as the system approaches Carnot efficiency), it can lead to a more favorable trade-off between work and efficiency. The provided example introduces new possibilities for enhancing performance of thermal machines through finite-dimensional ancillary systems.

中文翻译：

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类奥托二冲程量子发动机的催化优势


我们演示了如何加入催化剂来提高热机的性能。具体来说，我们分析了最简单的发动机模型之一的效率，该模型仅以两个冲程运行，并由一对两级系统组成，可能由 $d$ 维催化剂辅助。当不存在催化作用时，机器的效率由奥托效率给出。引入催化剂可以构建一个克服这一限制的协议，同时新的效率可以以简单的形式表示为奥托公式的推广： $1-(1/d)({\omega }_c/{\omega }_h)$ 。该催化剂还提供了更大的操作参数范围，其中机器作为发动机工作。尽管发动机效率的提高大多伴随着工作产出的减少（当系统接近卡诺效率时接近于零），但它可以导致工作和效率之间更有利的权衡。所提供的示例引入了通过有限维辅助系统增强热机性能的新可能性。