Active Viscoelasticity of Odd Materials.

Debarghya Banerjee,Vincenzo Vitelli,Frank Jülicher,Piotr Surówka

doi:10.1103/physrevlett.126.138001

Abstract

The mechanical response of active media ranging from biological gels to living tissues is governed by a subtle interplay between viscosity and elasticity. We generalize the canonical Kelvin-Voigt and Maxwell models to active viscoelastic media that break both parity and time-reversal symmetries. The resulting continuum theories exhibit viscous and elastic tensors that are both antisymmetric, or odd, under exchange of pairs of indices. We analyze how these parity violating viscoelastic coefficients determine the relaxation mechanisms and wave-propagation properties of odd materials.

Highlights

The mechanical response of active media ranging from biological gels to living tissues is governed by a subtle interplay between viscosity and elasticity
From the swimming strokes of sperm cells to intracellular flows, biological systems present a wide variety of cases where chiral symmetry is broken [7,8,9,10,11,12]
Recent work on chiral active matter has shown that the presence of activity and chirality, breaking essential microscopic symmetries, leads to novel response functions and transport coefficients in active fluids and solids [16,17,18,19,20,21,22,23,24,25,26,27,28,29]

Summary

Active Viscoelasticity of Odd Materials

Debarghya Banerjee ,1,2 Vincenzo Vitelli, Frank Jülicher ,2,6 and Piotr Surówka 2,7,8,*. The resulting continuum theories exhibit viscous and elastic tensors that are both antisymmetric, or odd, under exchange of pairs of indices We analyze how these parity violating viscoelastic coefficients determine the relaxation mechanisms and wave-propagation properties of odd materials. Materials at the macroscopic scales are often described either as a fluid or as a solid Such idealized behaviors are insufficient to describe materials that exhibit more complex mesoscopic organization. The main goal of this Letter is to combine these two formulations through a systematic description of chiral active systems based on symmetry principles This leads to a hydrodynamic theory of active odd viscoelastic solids and liquids, distinguished by a long-time response to static and dynamic deformations. These two distinct limiting cases of viscoelastic behavior are commonly described by the Maxwell and Kelvin-Voigt models, respectively.

Published by the American Physical Society

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