论文标题

学习布朗电影的非平衡动力学

Learning the Non-Equilibrium Dynamics of Brownian Movies

论文作者

Gnesotto, F. S., Gradziuk, G., Ronceray, P., Broedersz, C. P.

论文摘要

延时显微镜成像可直接访问软体和生活系统的动力学。在介观尺度上,这种显微镜实验揭示了内在波动,可能具有热和非平衡的起源。这些固有的波动以及测量噪声对分析这些“布朗电影”的动态构成了一个重大挑战。传统上,分析此类实验数据的方法依赖于跟踪嵌入的或内源性探针。但是,通常不清楚如何选择合适的示踪剂。这并不明显,尤其是在复杂的多体系统中,哪个自由度是其非平衡性质最有用的。在这里,我们介绍了一种替代性,无跟踪的方法,该方法通过对布朗电影的无监督分析来克服这些困难。我们开发了一个尺寸还原方案,该方案选择基于耗散模式的基础,然后我们在此基础上学习非平衡动力学并估计熵产生速率。此外,我们推断系统中的时间分辨力图,并表明该方法可扩展到大型系统,从而提供了微观力量探针的潜在替代方法。在针对最小两珠模型进行基准测试方法之后,我们以受活跃的生物聚合物凝胶启发的示例说明了其更广泛的适用性。

Time-lapse microscopy imaging provides direct access to the dynamics of soft and living systems. At mesoscopic scales, such microscopy experiments reveal intrinsic fluctuations, which may have both thermal and non-equilibrium origins. These intrinsic fluctuations, together with measurement noise, pose a major challenge for the analysis of the dynamics of these "Brownian movies". Traditionally, methods to analyze such experimental data rely on tracking embedded or endogenous probes. However, it is in general unclear how to select appropriate tracers; it is not evident, especially in complex many-body systems, which degrees of freedom are the most informative about their non-equilibrium nature. Here, we introduce an alternative, tracking-free approach that overcomes these difficulties via an unsupervised analysis of the Brownian movie. We develop a dimensional reduction scheme that selects a basis of modes based on dissipation, and we subsequently learn the non-equilibrium dynamics in this basis and estimate the entropy production rate. In addition, we infer time-resolved force maps in the system and show that this approach is scalable to large systems, thus providing a potential alternative to microscopic force-probes. After benchmarking our method against a minimal two-beads model, we illustrate its broader applicability with an example inspired by active biopolymer gels.

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