论文标题

手性主动己酸:巨大数字波动,波浪和秩序的破坏

Chiral active hexatics: Giant number fluctuations, waves and destruction of order

论文作者

Maitra, Ananyo, Lenz, Martin, Voituriez, Raphael

论文摘要

由内部驱动的颗粒组成的活性材料具有与热平衡时物质不同的特性。然而,偏离平衡相行为的最壮观的偏离被认为仅限于具有极性或列不对称的系统。在本文中,我们表明,如果组成粒子具有手性不对称性,则此类离开也显示在更对称的阶段,例如己酸盐。我们表明,旋转速率不取决于密度的手性活动己酸酯具有巨大的数量波动。如果旋转速率取决于密度,则由于新型的定向密度声音模式,巨大的数量波动被抑制,线性分散液也会在过度阻尼的极限下传播。但是,我们证明,除了有限但长度大的尺寸之外,手性和活动引起的相关非线性使线性理论的预测无效并破坏了示型秩序。此外,我们表明活动会修改活性手性六角形阶段缺陷之间的相互作用,使其无情。最后,为了证明手性活性六个相的通用性,我们表明它是由于有限系统中手性活性晶体的融化而引起的。

Active materials, composed of internally driven particles, have properties that are qualitatively distinct from matter at thermal equilibrium. However, the most spectacular departures from equilibrium phase behaviour are thought to be confined to systems with polar or nematic asymmetry. In this paper, we show that such departures are also displayed in more symmetric phases such as hexatics if, in addition, the constituent particles have chiral asymmetry. We show that chiral active hexatics whose rotation rate does not depend on density have giant number fluctuations. If the rotation rate depends on density, the giant number fluctuations are suppressed due to a novel orientation-density sound mode with a linear dispersion which propagates even in the overdamped limit. However, we demonstrate that beyond a finite but large lengthscale, a chirality and activity-induced relevant nonlinearity invalidates the predictions of the linear theory and destroys the hexatic order. In addition, we show that activity modifies the interactions between defects in the active chiral hexatic phase, making them non-mutual. Finally, to demonstrate the generality of a chiral active hexatic phase we show that it results from the melting of chiral active crystals in finite systems.

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