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arXiv · 2510.18309

Fluctuations in first passage times and utility of resetting protocol in biochemical systems with two-state toggling

Hillol Kumar Barman·Pathik Das·Syed Yunus Ali
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Abstract

Interesting theoretical problems of target search or threshold crossing, formally known as {\it first passage}, often arise in both diffusive transport problems as well as problems of chemical reaction kinetics. We study three systems following different chemical kinetics, and are special as they {\it toggle between two states}: (i) a population dynamics of cells with auto-catalytic birth and intermittent toxic chemical-induced forced death, (ii) a bond cluster model representing membrane adhesion to extracellular matrix under a fluctuating load, and (iii) a model of gene transcription with a regulated promoter switching between active and inactive states. Each of these systems has a target state to attain, which defines a first passage problem -- namely, population becoming extinct, complete membrane detachment, or mRNA count crossing a threshold. We study the fluctuations in first passage time and show that it is interestingly {\it non-monotonic} in all these cases, with increasing strength of bias towards the target. We also study suitable {\it stochastic resetting} protocols to expedite first passage for these systems, and show that there is a re-entrant transition of the efficacy of this protocol in all the three cases, as a function of the bias. The exact analytical condition for these transitions predicted in earlier literature is verified here through simulations.

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Hillol Kumar Barman, Pathik Das, Syed Yunus Ali. 2025-10-21. Fluctuations in first passage times and utility of resetting protocol in biochemical systems with two-state toggling. https://doi.org/10.1021/acs.jpcb.5c04647

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