Predictive modeling of interacting active Brownian particles

A predictive field-theoretical modeling of the dynamics of interacting active Brownian particles (ABPs) is challenging, but highly desirable since it allows for quantitative results. In this talk, we present an analytic representation for the full pair-distribution function of a homogeneous suspension of ABPs [1] and show how it can be used to derive predictive field theories for the collective dynamics of ABPs. We present predictive local models for both ordinary ABPs [2,3] and active Brownian circle swimmers [4]. The models yield analytic expressions for the density-dependent mean swimming speed, the spinodal corresponding to the onset of motility-induced phase separation, and the associated critical point as well as a mapping between circle swimmers and ordinary ABPs. All analytic results are shown to be in very good agreement with results of corresponding Brownian dynamics simulations and findings from the literature.

[1] J. Jeggle, J. Stenhammar, R. Wittkowski, J. Chem. Phys. 152, 194903 (2020)
[2] J. Bickmann, R. Wittkowski, J. Phys. Condens. Matter 32, 214001 (2020)
[3] J. Bickmann, R. Wittkowski, Phys. Rev. Res. 2, 033241 (2020)
[4] J. Bickmann, S. Bröker, J. Jeggle, R. Wittkowski, arXiv:2010.05262 (2020)