Programme

P.10 -- Poster, ANSWCCMS-2023

Date: Tuesday, 7 November 2023

Time: 13:00 - 14:30

Statistical Properties of Evanescent Self-Propelled Particles

Christine Joy G. Aban (1),(2 ) and Jose Perico H. Esguerra (1)

(1) Theoretical Physics Group, National Institute of Physics, University of the Philippines, Diliman Quezon City, 1101 Philippines (2) Theoretical Physics Group, Department of Physics, Mindanao State University - Iligan Institute of Technology, Andres Bonifacio Avenue, Tibanga, Iligan City, 9200 Philippines

Self-propelled particles (SPP) are active particles that take up energy from the environment and utilize some of the energy into directed motion allowing them to explore their surroundings. One way of studying the statistical behavior of these particles is through the run-and-tumble movement. Statistical properties such as probability distributions with and without diffusion terms and first passage properties of these active particles were investigated in the previous studies. However, the effects of death on the first passage properties were not considered. For example, Escherichia coli bacteria are self-propelling particles that move in a run-and-tumble way in order to navigate in search of food or nutrients and move away from chemical toxins. These microorganisms may die in a process called programmed cell death (PCD), where the death of a cell happens as a result of events inside of it. With this motivation, we define evanescent self-propelling particles as active particles that may die, decay, or disappear while moving towards or away from the boundaries. In this study, we investigate the effect of evanescence or mortality on the statistical properties of self-propelling particles moving in a run-and-tumble manner. Particularly, we obtained the occupational probability in the Laplace space and the first passage characteristics of evanescent run-and-tumble particle systems under spatially symmetric and partially absorbing or reflecting boundaries. We carried out the study by adding a death term in the Master equations describing the motion of active particles. From the differential equations, we derived a modified Telegrapher’s equation. Using Laplace transform and generating function methods, we calculated a general form of the eventual absorption probability and the conditional mean first passage time for evanescent run-and-tumble particles. We found that the increase in the death rate of the system resulted in a decrease in the particle’s first passage properties specifically in its eventual absorption probability and conditional mean first passage time. The decrease may correspond to the particles’ shorter run length as death may occur faster before the particle reaches a boundary.

Presenter: Christine Joy G. Aban

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