Dynamics of active run and tumble and passive particles in binary mixture

Vivek Semwal; Anish Kumar; Jay Prakash Singh; Shradha Mishra

doi:10.1140/epjs/s11734-024-01109-2

2024 Impact factor 2.3

Special Topics

Biomimetic and Cellular Membranes

Eur. Phys. J. Spec. Top. (2024) 233: 3185-3192
https://doi.org/10.1140/epjs/s11734-024-01109-2

Regular Article

Dynamics of active run and tumble and passive particles in binary mixture

Vivek Semwal², Anish Kumar¹, Jay Prakash Singh³ and Shradha Mishra¹^a

¹ Indian Institute of Technology (BHU) Varanasi, 221005, Varanasi, India
² RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
³ Israel Institute of Technology Technion, 3200003, Haifa, Israel

^a smishra.phy@itbhu.ac.in

Received: 18 October 2023
Accepted: 22 January 2024
Published online: 16 February 2024

Abstract

We study a binary mixture of disk-shaped active run and tumble particles (RTPs) and passive particles on a two-dimensional substrate. Both types of particles are athermal. The particles interact through the soft repulsive potential. The activity of RTPs is controlled by tuning their tumbling rate. The system is studied for various sizes of passive particles keeping size of RTPs fixed. Hence the variables are, size ratio (S) of passive particles and RTPs, and the activity of RTPs, v. The characteristic dynamics of both RTPs and passive particles show a crossover from early-time superdiffusive to later-time diffusive. Furthermore, we observed that passive particles dynamics changes from diffusive to subdiffusive with respect to their size. Moreover, late time effective diffusivity $D_{eff}$ $D_{eff}$ of passive particles decreases with increasing their size as in the corresponding equilibrium Stokes systems. We calculated the effective temperatures, using $D_{eff}$ $D_{eff}$ , $T_{a, e f f} (Δ)$ $T_{a,eff}(\Delta )$ and also using speed distribution $T_{a, e f f} (v)$ $T_{a,eff}(v)$ and compared them. The both $T_{a, e f f} (Δ)$ $T_{a,eff}(\Delta )$ and $T_{a, e f f} (v)$ $T_{a,eff}(v)$ increases linearly with activity and are in agreement with each other. Hence we can say that an effective equilibrium can be established in such a binary mixture. Our study can be useful to study the various biological systems like; dynamics of passive organelles in cytoplasm, colloids etc.

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Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

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