Mapping two-dimensional polar active fluids to two-dimensional soap and one-dimensional sandblasting

作者：Chen, Leiming^*; Lee, Chiu Fan^*; Toner, John^*

来源：Nature Communications, 2016, 7(1): 12215.

DOI：10.1038/ncomms12215

• PARISI-ZHANG MODEL
• LONG-RANGE ORDER
• LIQUID-CRYSTALS
• FLOCKS
• ELASTICITY
• PARTICLES
• DYNAMICS
• SCHOOLS
• ABSENCE
• MOTION

Active fluids and growing interfaces are two well-studied but very different non-equilibrium systems. Each exhibits non-equilibrium behaviour distinct from that of their equilibrium counterparts. Here we demonstrate a surprising connection between these two: the ordered phase of incompressible polar active fluids in two spatial dimensions without momentum conservation, and growing one-dimensional interfaces (that is, the 1 + 1-dimensional Kardar-Parisi-Zhang equation), in fact belong to the same universality class. This universality class also includes two equilibrium systems: two-dimensional smectic liquid crystals, and a peculiar kind of constrained two-dimensional ferromagnet. We use these connections to show that two-dimensional incompressible flocks are robust against fluctuations, and exhibit universal long-ranged, anisotropic spatio-temporal correlations of those fluctuations. We also thereby determine the exact values of the anisotropy exponent zeta and the roughness exponents chi(x,y) that characterize these correlations.

• 出版日期2016-7
• 单位中国矿业大学（北京）