Year: 2026
Type: preprint
Abstract: Motivated by experiments on light-patterned, quasi-2D active suspensions that exhibit large density variations, we develop a continuum theory of compressible active nematics--suspensions of apolar rods whose orientation is invariant under $π$ rotations. Under spatially patterned activity, the extensile isotropic active pressure expels material from high-activity regions and accumulates it in low-activity ones; an exactly solvable scalar reduction shows that the resulting density contrast is governed by a single dimensionless parameter, linear in the compressibility. Using compressibility as a tuning knob, we then steer active turbulence from high- to low-activity regions and, at sharp activity interfaces, stabilize an analytically tractable dynamical steady state: a one-dimensional chain of vortices held by soft, activity-induced confinement. Our results establish compressibility as a control parameter for density variations and turbulent flow in active nematic suspensions.
Source: arXiv (Cornell University)
Institutions: University of California, Santa Barbara, Brandeis University
Language: English
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
Awards: Collaborative Research: DMREF: Synthetic machines from feedback-controlled active matter, Active Patterns in Soft and Living Matter, Robustness and Uniqueness in Fingerprint Morphogenesis, Bioinspired Soft Materials, G3398237449, G3696745163, G4689434848, Kavli Institute for Theoretical Physics, G7833242660, Developing quantitative continuum theories of composite active fluids
OpenAlex ID: W7171645658