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Updated: Jan 2, 2026
11:03
An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
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Predictive local field theory for interacting active Brownian spheres in two spatial dimensions.
Jens Bickmann1, Raphael Wittkowski1
1Institut für Theoretische Physik, Center for Soft Nanoscience, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany.
Summary
We developed a new theory for active Brownian particles, predicting their movement and phase separation. This model accurately describes particle interactions and predicts key properties like motility-induced phase separation.
Area of Science:
- Statistical physics
- Soft matter physics
- Active matter
Background:
- Active Brownian particles (ABPs) exhibit complex nonequilibrium dynamics.
- Understanding collective behavior, like motility-induced phase separation (MIPS), is crucial.
Purpose of the Study:
- To develop a predictive local field theory for interacting ABPs in 2D.
- To provide explicit expressions for model coefficients and predict MIPS.
Main Methods:
- Rigorous coarse-graining from Langevin equations.
- Inclusion of infinite-order configurational order parameters.
- Analysis of reduced models and linear stability analysis.
Main Results:
- The theory unifies existing models like Active Model B+.
- Analytical expression for density-dependent mean swimming speed derived.
- Accurate prediction of MIPS spinodal and critical point for repulsive interactions.
Conclusions:
- The predictive local field theory accurately describes ABP dynamics and MIPS.
- The theory offers a powerful analytical tool for active matter systems.
- Excellent agreement between analytical predictions and Brownian dynamics simulations.
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