论文标题
在粘弹性主动悬架中运行的布朗循环发动机
A Brownian cyclic engine operating in a viscoelastic active suspension
论文作者
论文摘要
我们研究了一个模型，该模型由由谐波电位限制的被动布朗粒子组成，并与粘性溶剂中自propel的悬浮液相互作用，该剂量在粘性溶剂中自propel，该溶剂在等温条件下通过陷阱刚度的时间变化在等温条件下进行操作。我们得出了被困的布朗粒子运动的有效随机方程，其中包括摩擦记忆内核以及由于其与主动悬浮液的耦合而导致的热和主动波动力，我们可以分析地计算出在准静态极限中发动机的效率。我们发现，平均而言，发动机能够以效率产生机械工作，取决于系统的不同时间尺度之间的相互作用，在这种情况下，与瞬时摩擦的系统相比，与瞬间悬挂的随之而来的粘弹性的一般效果是降低布朗尼发动机的准静态效率。然而，系统的参数空间中有一些区域，在发动机的性能中，这种记忆效应可以忽略不计，因此有效地行为与惰性粘性浴在两个不同温度下的惰性粘性浴场接触，这与活动粒子的推进速度相关。
We investigate a model for a Stirling-like engine consisting of a passive Brownian particle confined by a harmonic potential and interacting with a suspension of active Brownian particles that self-propel in a viscous solvent, which cyclically operates under isothermal conditions by means of temporal variations of the trap stiffness and the self-propulsion speed of the active particles. We derive an effective stochastic equation of motion of the trapped Brownian particle, which includes a friction memory kernel as well as thermal and active fluctuating forces due to its coupling with the active suspension, from which we analytically compute the efficiency of the engine in the quasi-static limit. We find that, on average, the engine is capable to produce mechanical work with an efficiency that depends on the interplay between the different time-scales of the system, where the general effect of the ensuing viscoelasticity of the active suspension is to reduce the quasi-static efficiency of the Brownian engine, as compared to the case of a system with instantaneous friction. Nevertheless, there are regions in the parameters space of the system where such memory effects are negligible in the performance of the engine, thus effectively behaving as in contact with an inert viscous bath working at two different temperatures related to the propulsion speed of the active particles.
