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arXiv · 1312.7242

Effective Cahn-Hilliard equation for the phase separation of active Brownian particles

Thomas Speck·Julian Bialké·Andreas M. Menzel·Hartmut Löwen
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Abstract

The kinetic separation of repulsive active Brownian particles into a dense and a dilute phase is analyzed using a systematic coarse-graining strategy. We derive an effective Cahn-Hilliard equation on large length and time scales, which implies that the separation process can be mapped onto that of passive particles. A lower density threshold for clustering is found, and using our approach we demonstrate that clustering first proceeds via a hysteretic nucleation scenario and above a higher threshold changes into a spinodal-like instability. Our results are in agreement with particle-resolved computer simulations and can be verified in experiments of artificial or biological microswimmers.

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Thomas Speck, Julian Bialké, Andreas M. Menzel, Hartmut Löwen. 2013-12-27. Effective Cahn-Hilliard equation for the phase separation of active Brownian particles. https://doi.org/10.1103/physrevlett.112.218304

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