We experimentally investigate the work fluctuations of an active Brownian particle (ABP) during its self-propelled motion in a viscoelastic medium. Under such conditions, ABPs display a persistent circular motion which allows the determination of the orientational work fluctuations along its trajectory. Due to the nonlinear coupling to the non-Markovian bath, we find strong deviations from the work fluctuation theorem (WFT) due to observed increased rotational ABP dynamics. Taking this enhanced rotational diffusion into account, the orientational work distributions can be recasted to be in accordance with the WFT by considering an effective temperature of about two orders of magnitude larger than $k_{\mathrm{B}}T$. This approach is confirmed by the good agreement of the torque exerted by the viscoelastic bath on the ABP obtained from the WFT with the value obtained from the mean angular velocity and the friction coefficient of the ABP.

中文翻译：

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粘弹性流体中活性布朗粒子的功脉动关系

我们通过实验研究了活性布朗粒子 (ABP) 在粘弹性介质中自推进运动期间的功波动。在这种情况下，ABP 显示出持续的圆周运动，从而可以确定沿其轨迹的定向工作波动。由于与非马尔可夫浴的非线性耦合，我们发现由于观察到的旋转 ABP 动力学增加而与功波动定理 (WFT) 存在很大偏差。考虑到这种增强的旋转扩散，通过考虑比 WFT 大两个数量级的有效温度，可以将取向功分布重新调整为与 WFT 一致。${克}_{\mathrm{乙}}吨$. 这种方法通过粘弹性浴施加在从 WFT 获得的 ABP 上的扭矩与从平均角速度和 ABP 的摩擦系数获得的值的良好一致性得到证实。