Quasi-Long-Ranged Order in Two-Dimensional Active Liquid Crystals

Physical Review Letters, vol. 134, pp. 128304

Abstract

Quasi-long-ranged order is the hallmark of two-dimensional liquid crystals. At equilibrium, this property implies that the correlation function of the local orientational order parameter decays with distance as a power law: i.e., ∼|r|^{-η_{p}}, with η_{p} a temperature-dependent exponent. While in general nonuniversal, η_{p}=1/4 universally at the Berezinskii-Kosterlitz-Thouless transition, where orientational order is lost because of the unbinding of disclinations. Here, we demonstrate that, in active liquid crystals, the notion of quasi-long-ranged order fundamentally differs from its equilibrium counterpart, and the exponent η_{p} is allowed to vary in the range 0<η_{p}≤2, with the upper bound corresponding to the isotropic phase. Our theoretical predictions are supported by a survey of a variety of experimental realizations of two-dimensional active liquid crystals.

Authors 4

1. Livio Nicola Carenza Aachen

   Leiden University · Koç University

   Affiliation as printed

   Koç University

   Universiteit Leiden

2. Josep-Maria Armengol-Collado Aachen

   Leiden University

   Affiliation as printed

   Universiteit Leiden

3. Dimitrios Krommydas Aachen

   Leiden University

   Affiliation as printed

   Universiteit Leiden

4. Luca Giomi corresponding Aachen

   Leiden University

   Affiliation as printed

   Universiteit Leiden