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

Autor: Josué Manik Nava-Sedeño, Haralampos Hatzikirou, Anja Voß-Böhme, Lutz Brusch, Andreas Deutsch, Fernando Peruani
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: New Journal of Physics, Vol 25, Iss 12, p 123046 (2023)
Druh dokumentu: article
ISSN: 1367-2630
DOI: 10.1088/1367-2630/ad1498
Popis: 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.
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