单弛豫粘弹性流体中的主动布朗运动
Active Brownian motion in a single-relaxation viscoelastic fluid
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中文总结 AI 辅助
该研究扩展了模拟单弛豫粘弹性流体的布朗动力学模型，分析并模拟了主动布朗粒子在粘弹性介质中的两类主导动力学 regime，与实验定量吻合，为相关研究提供了可控的粘弹性环境。
中文摘要 AI 辅助
粘弹性（VE）介质中的主动布朗粒子（ABPs）会呈现出由自推进、热涨落和流体粘弹性共同决定的有趣动力学现象。我们扩展了此前的模型，该模型中慢扩散简谐势阱内的布朗动力学可模拟单弛豫VE流体中的动力学，以此研究这类介质中的主动布朗运动。由此产生的动力学由系统特征时间尺度的相互作用决定：VE流体的交叉时间τ_k和平衡时间λ，以及ABP的 persistence 时间τ_R。基于分析预测和模拟，我们研究了两类具有实际意义的 regime，分别对应动力学由主动运动的 persistence 和 VE 流体的弹性约束主导，实验采用动态光阱中的电泳活性铂包被的Janus胶体，结果与模拟定量吻合。该方法可提供粘弹性质可调且不受自推进强度影响的VE环境，使我们能以物理VE流体无法实现的方式系统研究VE介质中的主动布朗运动。
英文摘要
Active Brownian particles (ABPs) in viscoelastic (VE) media exhibit fascinating dynamical phenomena set by self-propulsion, thermal fluctuations, and fluid viscoelasticity. We extend our model, in which the Brownian dynamics within a slowly diffusing harmonic well emulates that in a single-relaxation VE fluid, to study active Brownian motion in such media. Consequently, the resultant dynamics is governed by the interplay of the characteristic timescales of the systems: the crossover and equilibration times of the VE fluid, $τ_k$ and $λ$, respectively, and the persistence time of the ABP, $τ_{\mathrm{R}}$. Following analytical predictions and simulations, we study two practically relevant regimes where the dynamics is dominated by the persistence of active motion and the elastic confinement of the VE fluid, with a phoretically active Pt-coated Janus colloid in a dynamic optical trap, and show quantitative agreement with the simulations. This approach provides a VE environment with tunable VE properties that remain unaffected by the strength of self-propulsion, allowing us to systematically investigate active Brownian motion in VE media in ways that are not otherwise possible with physical VE fluids.
