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arXiv 2402.04450cond-mat.softcond-mat.stat-mechnlin.CGphysics.bio-ph
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晶格上的矢量活性物质:极性凝聚体与向列丝状结构

Vectorial active matter on the lattice: polar condensates and nematic filaments

Josué Manik Nava-Sedeño, Haralampos Hatzikirou, Anja Voß-Böhme, Lutz Brusch, Andreas Deutsch, Fernando Peruani

AI总结:

本研究提出晶格上的矢量活性物质模型,发现极性与向列对齐分别导致极性凝聚体和向列丝状结构,并推导流体动力学方程,揭示晶格对称性对涌现性质的影响。

摘要:

我们提出了一种新型的格子气元胞自动机(LGCA),用于描述具有极性和向列速度对齐的可压缩矢量活性物质。相互作用在构造上为零程。对于极性对齐,我们证明系统经历了一个相变,该相变促进了聚集,与经典的零程过程有很强的相似性。我们发现,在临界点之上,系统中宏观比例的粒子状态合并为同一状态,共享相同的位置和动量(极性凝聚体)。对于向列对齐,系统也表现出凝聚现象,但存在根本性的差异:系统中宏观比例的粒子坍缩成一条丝状结构,其中粒子仅具有两种可能的动量。此外,我们推导了活性LGCA模型的流体动力学方程,以理解系统经历的相变和凝聚。我们还表明,通常离散晶格对称性——例如正方形或六边形晶格——会显著影响晶格上活性系统涌现的大尺度性质。该研究揭示了晶格上对齐的活性物质展现出新的行为,包括向与凝聚模型相似的态的相变。

英文摘要:

We introduce a novel lattice-gas cellular automaton (LGCA) for compressible vectorial active matter with polar and nematic velocity alignment. Interactions are, by construction, zero-range. For polar alignment, we show the system undergoes a phase transition that promotes aggregation with strong resemblance to the classic zero-range process. We find that above a critical point, the states of a macroscopic fraction of the particles in the system coalesce into the same state, sharing the same position and momentum (polar condensate). For nematic alignment, the system also exhibits condensation, but there exist fundamental differences: a macroscopic fraction of the particles in the system collapses into a filament, where particles possess only two possible momenta. Furthermore, we derive hydrodynamic equations for the active LGCA model to understand the phase transitions and condensation that undergoes the system. We also show that generically the discrete lattice symmetries -- e.g. of a square or hexagonal lattice -- affect drastically the emergent large-scale properties of on-lattice active systems. The study puts in evidence that aligning active matter on the lattice displays new behavior, including phase transitions to states that share similarities to condensation models.

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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