Regensburg 2022 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 20: Active Matter 4 (joint session DY/BP/CPP)
BP 20.7: Vortrag
Mittwoch, 7. September 2022, 16:45–17:00, H18
Active motion with varying self propulsion — Lorenzo Caprini1, Alexander R. Sprenger1, Umberto M. B. Marconi2, Hartmut Löwen1, and •René Wittmann1 — 1Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine Universität Düsseldorf, Germany — 2School of Sciences and Technology, University of Camerino, Italy
Active Brownian Particles (ABPs), commonly perceived as the standard model for (dry) active motion, are characterized by a constant self-propulsion velocity along the direction of a unit vector which performs rotational diffusion. In nature, however, the swim velocity is usually not a constant in time and space. Here, we present a generic form of the equations of motion of active particles, which account for two aspects of varying self propulsion. First, we introduce a general stochastic process with fluctuating modulus of the self-propulsion vector, which defines a parental active model (PAM). We argue that the two well-known models of ABPs and Active Ornstein-Uhlenbeck Particles (AOUPs) emerge as limiting cases of the PAM [1], i.e., they are rather sisters than cousins. Second, we demonstrate that a position-dependent swim-velocity field can be consistently introduced for any self-propulsion mechanism [2]. Finally, we discuss the effects of varying self propulsion in external confinement [1,3] and predict the stationary probability distributions in terms of effective interactions [3].
[1] L. Caprini et al., J. Chem. Phys. 156, 071102 (2022).
[2] L. Caprini et al., Soft Matter, 18, 1412 (2022).
[3] L. Caprini et al., arXiv:2203.00603 (2022).