Universal scaling of segment fluctuations in polymer and chromatin dynamics

Kirill Polovnikov; Mehran Kardar

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arXiv · 2505.10943

Universal scaling of segment fluctuations in polymer and chromatin dynamics

Kirill Polovnikov·Mehran Kardar

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Abstract

We demonstrate how center-of-mass (COM) motion influences polymer segment fluctuations. Cancellation of internal forces, together with spatially uncorrelated external noise, generally yields COM diffusivity scaling as $1/s$ with segment length $s$, regardless of fractal dimension, viscoelasticity, or activity. This introduces distinct dynamic scaling corrections to two-point fluctuations and quenched-induced tangential correlations, validated by theory, simulations, and chromatin imaging data. In the latter, the extracted dynamic exponent reveals topological constraints, thereby resolving the discrepancy between chromatin's crumpled structure and its Rouse-like dynamics.

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Kirill Polovnikov, Mehran Kardar. 2025-05-16. Universal scaling of segment fluctuations in polymer and chromatin dynamics. https://arxiv.org/abs/2505.10943

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