Spatiotemporal crystallization of an active fluid

TL;DR

This paper demonstrates how a chaotic active nematic can spontaneously organize into a stable spatiotemporal crystal lattice, revealing new insights into order formation in active matter systems.

Contribution

It introduces the formation of spatiotemporal crystals in active fluids through spontaneous synchronization, supported by experimental and simulation evidence.

Findings

Spatiotemporal lattices form without external forcing.

Order arises from intrinsic flow instabilities and confinement.

Simulations confirm the role of intrinsic length and time scales.

Abstract

The emergence of long-range spatiotemporal order from intrinsic chaos is a central challenge in far-from-equilibrium physics. In active fluids, such as cytoskeletal networks driving cellular motion, self-generated flows typically produce "active turbulence", lacking translational symmetry. Here we show that a chaotic active nematic can self-organize into a spatiotemporal crystal, forming a regular lattice of density, orientation, and vorticity that breaks both spatial and temporal translational symmetry. Using a microtubule/kinesin active nematic interfaced with a lamellar liquid crystal and confined in microfluidic channels, we observe robust spatiotemporal lattices without external forcing. The ordering emerges from spontaneous synchronization of intrinsic flow instabilities, mediated by confinement and feedback between the active layer and the passive anisotropic interface. Continuum nematohydrodynamics simulations support our interpretation, highlighting how intrinsic length and time scales shape the active crystals. These results reconcile chaos and crystallinity in active matter and provide a strategy for engineering order in self-driven, far-from-equilibrium soft materials.