Microorganisms such as bacteria are active matter which consume chemical energy and generate their unique run-and-tumble motion. A swarm of such microorganisms provide a nonequilibrium active environment whose noise characteristics are different from those of thermal equilibrium reservoirs. One important difference is a finite persistence time, which is considerably large compared to that of the equilibrium noise, that is, the active noise is colored. Here we study a mesoscopic energy-harvesting device (engine) with active reservoirs harnessing this noise nature. For an exactly solvable linear model, we show that the performance from the active environment can surpass that from the equilibrium environment. Furthermore, we propose a proper definition of the active-reservoir temperature and show that the engine efficiency can overcome the conventional Carnot bound, thus the power-efficiency trade-off constraint is released. We also show that the efficiency at the maximum power can surpass the Curzon-Ahlborn efficiency. This remarkable enhancement originates from the extra unconventional entropy production beyond the conventional Clausius entropy production, due to the non-Markovian nature of the active reservoirs. Interestingly, the supremacy of the active engine critically depends on the timescale symmetry of two active reservoirs.

中文翻译：

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带有主动水箱的布朗热机

微生物（例如细菌）是消耗化学能并产生其独特的运行运动的活性物质。大量此类微生物提供了一个非平衡的活动环境，其噪声特性不同于热平衡池的噪声特性。一个重要的区别是有限的持续时间，与平衡噪声相比，这是相当大的，也就是说，有源噪声是有色的。在这里，我们研究了一种介观的能量收集装置（发动机），该装置具有利用这种噪声性质的有源储层。对于一个完全可解的线性模型，我们证明了活跃环境下的性能可以超过均衡环境下的性能。此外，我们提出了一个有效的储层温度定义，并表明发动机效率可以克服传统的卡诺界限，从而释放了功率效率的权衡约束。我们还表明，最大功率下的效率可以超过Curzon-Ahlborn效率。由于活动储层的非马尔可夫性质，这种非凡的增强源自于超出常规克劳修斯熵产生的额外非常规熵产生。有趣的是，主动发动机的至高关键性地取决于两个主动油库的时标对称性。由于活动储层的非马尔可夫性质，这种非凡的增强源自于超出常规克劳修斯熵产生的额外非常规熵产生。有趣的是，主动发动机的至高关键性地取决于两个主动油库的时标对称性。由于活动储层的非马尔可夫性质，这种非凡的增强来自于超出常规克劳修斯熵产生的额外非常规熵产生。有趣的是，主动发动机的至高关键性地取决于两个主动油库的时标对称性。