We analyse non-equilibrium Carnot-like cycles built with a colloidal particle in a harmonic trap, which is immersed in a fluid that acts as a heat bath. Our analysis is carried out in the overdamped regime. The cycle comprises four branches: two isothermal processes and two \textit{locally} adiabatic ones. In the latter, both the temperature of the bath and the stiffness of the harmonic trap vary in time, but in such a way that the average heat vanishes for all times. All branches are swept at a finite rate and, therefore, the corresponding processes are irreversible, not quasi-static. Specifically, we are interested in optimising the heat engine to deliver the maximum power and characterising the corresponding values of the physical parameters. The efficiency at maximum power is shown to be very close to the Curzon-Ahlborn bound over the whole range of the ratio of temperatures of the two thermal baths, pointing to the near optimality of the proposed protocol.

中文翻译：

---

用过阻尼谐振子构建不可逆的类卡诺热机

我们分析了非平衡卡诺循环，该循环是用谐波阱中的胶体粒子构建的，谐波阱浸入充当热浴的流体中。我们的分析是在过阻尼状态下进行的。该循环包括四个分支：两个等温过程和两个 \textit{locally} 绝热过程。在后者中，浴的温度和谐波阱的刚度都随时间变化，但平均热量始终消失。所有分支都以有限速率扫描，因此，相应的过程是不可逆的，而不是准静态的。具体而言，我们对优化热机以提供最大功率和表征物理参数的相应值感兴趣。