Efficiency fluctuations in steady-state machines

作者：Marc Suñé, Alberto Imparato · 发表于：Journal of Physics A Mathematical and Theoretical · 年份：2018 · DOI：10.1088/1751-8121/aaf2f8 · 被引用次数：14 · 研究领域：Advanced Thermodynamics and Statistical Mechanics、stochastic dynamics and bifurcation、Micro and Nano Robotics

Abstract We study the statistics of the efficiency in a class of isothermal cyclic machines with realistic coupling between the internal degrees of freedom. We derive, under fairly general assumptions, the probability distribution function for the efficiency. We find that the macroscopic efficiency is always equal to the most likely efficiency, and it lies in an interval whose boundaries are universal as they only depend on the input and output thermodynamic forces, and not on the details of the machine. The machine achieves the upper boundary of such an interval only in the limit of tight coupling. Furthermore, we find that the tight coupling limit is a necessary, yet not sufficient, condition for the engine to perform close to the reversible efficiency. The reversible efficiency is the least likely regardless of the coupling strength, in agreement with previous studies. By using a large deviation formalism for the energy currents we derive a fluctuation relation for the efficiency which holds for any number of internal degrees of freedom in the system.