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Published on: September 26, 2014
Odd Elasticity in Disordered Chiral Active Materials
Cheng-Tai Lee1, Tom C Lubensky2, Tomer Markovich1,3
1Tel Aviv University, School of Mechanical Engineering, Tel Aviv 69978, Israel.
Physical Review Letters
|July 31, 2026
Summary
Chiral active materials exhibit "odd" elasticity, a novel response emerging from internal particle rotations in disordered systems. This study models these odd solids, revealing new instabilities and wave propagation phenomena in odd fluid environments.
Area of Science:
- Physics
- Materials Science
- Biophysics
Background:
- Chiral active materials, found in biological systems like the cytoskeleton and bacterial flagella, break time reversal and parity symmetries.
- These materials exhibit a unique elastic response known as
- odd
- elasticity.
- Current understanding of odd elasticity is limited to ordered structures, leaving its emergence in disordered natural systems unexplored.
Purpose of the Study:
- To develop a generic model for disordered
- odd solids
- to understand the emergence of odd elasticity.
- To investigate the viscoelastic behavior of these odd solids when interacting with odd fluids.
Main Methods:
- Utilized micropolar (Cosserat) elasticity theory.
- Incorporated local active torques to model disordered systems.
- Analyzed the nonlinear effects of internal particle rotations.
Main Results:
- Odd elasticity naturally emerges as a nonlinear consequence of internal particle rotations in disordered systems.
- New dynamically unstable regions were identified due to odd solid-fluid coupling, influenced by inertia in the underdamped regime.
- In the overdamped limit, odd solid-fluid coupling facilitates bulk wave propagation near unstable regions.
Conclusions:
- The proposed model provides a framework for understanding odd elasticity in disordered chiral active materials.
- The findings reveal novel dynamic instabilities and wave propagation mechanisms driven by the interplay between odd solids and odd fluids.
- This research bridges the gap between theoretical models of odd elasticity and its manifestation in complex, natural systems.
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