Quan H T
School of Physics, Peking University, Beijing 100871, China and Collaborative Innovation Center of Quantum Matter, Beijing 100871, China.
Phys Rev E Stat Nonlin Soft Matter Phys. 2014 Jun;89(6):062134. doi: 10.1103/PhysRevE.89.062134. Epub 2014 Jun 25.
We study the maximum efficiency of a heat engine based on a small system. It is revealed that due to the finiteness of the system, irreversibility may arise when the working substance contacts with a heat reservoir. As a result, there is a working-substance-dependent correction to the Carnot efficiency. We derive a general and simple expression for the maximum efficiency of a Carnot cycle heat engine in terms of the relative entropy. This maximum efficiency approaches the Carnot efficiency asymptotically when the size of the working substance increases to the thermodynamic limit. Our study extends Carnot's result of the maximum efficiency to an arbitrary working substance and elucidates the subtlety of thermodynamic laws in small systems.
我们研究了基于小系统的热机的最大效率。结果表明，由于系统的有限性，当工作物质与热库接触时可能会产生不可逆性。因此，对卡诺效率存在与工作物质相关的修正。我们根据相对熵推导出了卡诺循环热机最大效率的一个通用且简单的表达式。当工作物质的尺寸增加到热力学极限时，这个最大效率渐近地趋近于卡诺效率。我们的研究将卡诺关于最大效率的结果扩展到了任意工作物质，并阐明了小系统中热力学定律的微妙之处。
