Universality for Moving Stripes: A Hydrodynamic Theory of Polar Active Smectics

TL;DR

This paper develops a hydrodynamic theory for polar active smectics, revealing phase transitions, order properties, and fluctuation behaviors in different dimensions and conservation scenarios.

Contribution

It introduces a comprehensive hydrodynamic framework for polar active smectics, analyzing order, phase transitions, and fluctuations with novel insights.

Findings

Quasi long-ranged smectic order in 2D without number conservation

Long-ranged smectic order in 3D without number conservation

Suppressed giant number fluctuations in number-conserving smectics

Abstract

We present a hydrodynamic theory of polar active smectics, for systems both with and without number conservation. For the latter, we find quasi long-ranged smectic order in d=2 and long-ranged smectic order in d=3. In d=2 there is a Kosterlitz-Thouless type phase transition from the smectic phase to the ordered fluid phase driven by increasing the noise strength. For the number conserving case, we find that giant number fluctuations are greatly suppressed by the smectic order; that smectic order is long-ranged in d=3; and that nonlinear effects become important in d=2.