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arXiv 1909.01375cond-mat.softcond-mat.stat-mech
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持久性活性物质:无吸引力的甘精胰岛素中的被捕态

Arrested States in Persistent Active Matter: Gelation without Attraction

Carl Merrigan, Kabir Ramola, Rakesh Chatterjee, Nimrod Segall, Yair Shokef, Bulbul Chakraborty

摘要:

我们探讨了相分离和动力学逮捕模型活性胶体系统组成的自推进,硬核颗粒与非凸形状。该模型的被动限制,即在正方形晶格上的十字形颗粒,表现出从流体相到固相的一阶转变,密度增加。淬火到两相共存区表现出老化制度。粒子的非凸形状减轻了无源系统中的干扰,并导致对有源粒子的旋转的强烈抑制。使用数值模拟和分析建模,我们量化的非平衡相行为的密度和活动的函数。如果我们将活性视为吸引力强度的模拟,则相图与有吸引力的胶体具有很强的相似性,表现出老化、玻璃态和凝胶状被捕态。这两种类型的动态逮捕的状态,玻璃和凝胶,是由密度不均匀性在后者的外观区分。在无限持久的限制,我们表明,基于不对称排斥过程的粗粒度模型定量预测的凝胶态的密度分布。有限的旋转速率的预测仍然定性有效。使用这些结果,我们分类活动驱动的阶段,并确定它们之间的边界。

英文摘要:

We explore phase separation and kinetic arrest in a model active colloidal system consisting of self-propelled, hard-core particles with nonconvex shapes. The passive limit of the model, namely cross-shaped particles on a square lattice, exhibits a first-order transition from a fluid phase to a solid phase with increasing density. Quenches into the two-phase coexistence region exhibit an aging regime. The nonconvex shape of the particles eases jamming in the passive system and leads to strong inhibition of rotations of the active particles. Using numerical simulations and analytical modeling, we quantify the nonequilibrium phase behavior as a function of density and activity. If we view activity as the analog of attraction strength, the phase diagram exhibits strong similarities to that of attractive colloids, exhibiting both aging, glassy states and gel-like arrested states. The two types of dynamically arrested states, glasses and gels, are distinguished by the appearance of density heterogenities in the latter. In the infinitely persistent limit, we show that a coarse-grained model based on the asymmetric exclusion process quantitatively predicts the density profiles of the gel states. The predictions remain qualitatively valid for finite rotation rates. Using these results, we classify the activity-driven phases and identify the boundaries separating them.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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