Fluctuation-induced forces in driven systems with a diffusivity anomaly.

Area of Science:

• Soft Matter Physics
• Statistical Mechanics
• Non-equilibrium Systems

Background:

• Boundary-driven systems exhibit complex behaviors.
• Diffusivity anomalies can significantly alter system dynamics.
• Casimir forces typically arise from quantum or thermal fluctuations.

Purpose of the Study:

• To investigate Casimir-like forces in systems with bulk diffusivity anomalies.
• To explore the role of cooperative dynamical effects on these forces.
• To determine if these forces can be locally controlled (attractive/repulsive).

Main Methods:

• Theoretical analysis using mean-field arguments.
• Explicit Casimir force evaluation within the fluctuating hydrodynamics framework.
• Monte Carlo simulations of a 2D exclusion process with kinetic constraints.

Main Results:

• Cooperative dynamical effects enhance Casimir-like forces.
• Forces can be made locally attractive or repulsive by adjusting boundary densities.
• Repulsive forces emerge when finite-size transverse density fluctuations exceed infinite-size values.

Conclusions:

• Bulk diffusivity anomalies are key to tuning fluctuation-induced forces.
• This work provides a framework for designing driven soft-matter systems.
• The findings align with the entropic interpretation of the Casimir effect.