Work

Universal center-of-mass scaling shapes segment fluctuations and chromatin dynamics

Year: 2025

Type: article

Abstract: We show that cancellation of internal forces together with spatially uncorrelated noise generically enforces a universal 1 / s scaling of the center-of-mass (COM) diffusivity for polymer segments of contour length s , independent of model details. Within an active generalized Rouse-Langevin (A-GRLE) framework for fractal polymers in a viscoelastic bath with weak activity, we derive closed-form links between segment COM motion and the short-time behavior of two-point fluctuations. The same COM law predicts transient s − 3 tangent-tangent correlations along the contour following a temperature quench. Reanalyzing recent two-locus chromatin tracking, we extract a dynamic COM exponent ξ = 0.77 ± 0.16 , suggesting topological constraints. These results identify model-independent signatures of collective polymer dynamics and clarify that the observed Rouse-like scaling of chromatin loci reflects transient, unentangled dynamics with an inevitable crossover to an entangled regime at longer times.

Source: Physical Review Research

DOI: 10.1103/ms1q-z8zp

Authors: Kirill E. Polovnikov, Mehran Kardar

Institutions: Skolkovo Institute of Science and Technology, University of Potsdam, Massachusetts Institute of Technology

Language: English

Topic: Fractional Differential Equations Solutions

Subfield: Modeling and Simulation

Field: Mathematics

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,625

Funders: National Science Foundation, Alexander von Humboldt-Stiftung, Russian Science Foundation