Nematodynamics with odd and rotational viscosities.

Area of Science:

• Soft Matter Physics
• Fluid Dynamics
• Continuum Mechanics

Background:

• Nematic liquid crystals exhibit complex behaviors influenced by flow and internal order.
• Existing models, like the Ericksen-Leslie formalism, can suffer from spurious instabilities due to Onsager's reciprocal relations.
• Understanding activity-induced instabilities is crucial for developing active soft matter systems.

Purpose of the Study:

• To explore a novel mechanism for nematic order and flow interactions, incorporating odd and rotational viscosities.
• To investigate activity-induced instabilities within this new theoretical framework.
• To address deficiencies in existing models related to spurious instabilities.

Main Methods:

• Incorporation of viscous dissipation modes into the Ericksen-Leslie formalism.
• Development of a new method for deriving nematodynamic equations based on rigid rod interactions.
• Analysis of instabilities in active media using the proposed model.

Main Results:

• The novel mechanism successfully incorporates odd and rotational viscosities.
• The proposed method for deriving equations avoids spurious instabilities inherent in Onsager-based approaches when no active inputs are present.
• The model is effectively applied to analyze instabilities in active nematic systems.

Conclusions:

• A new, more stable theoretical framework for active nematics has been established.
• The proposed derivation method offers an alternative to Onsager's reciprocal relations, mitigating spurious instabilities.
• This work provides a foundation for further research into active soft matter dynamics.