Regensburg 2025 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

DY: Fachverband Dynamik und Statistische Physik

DY 32: Nonlinear Stochastic Systems

DY 32.5: Vortrag

Donnerstag, 20. März 2025, 10:45–11:00, H43

Dynamic instability in dissipative self-assembly: common principles in single and multi-filament polymers — •Seeralan Sarvaharman and Aljaž Godec — Max Planck Insitute for Multidisciplinary Sciences, Göttingen, Germany

Dissipative self-assembly underpins the formation of complex biological structures by breaking time-reversal symmetry. Microtubules, essential cytoskeletal polymers, exemplify this through ``dynamic instability'', where the growth and shrinkage of the polymer are governed by the instantaneous composition of the constituent filaments. The microtubule length, the observable most commonly used to quantify this behaviour, obscures the many-body physics involved. As such, the principles underpinning this instability have remained elusive.

Here, we address this challenge by modelling the dynamics using a three-state Potts framework with thermodynamically consistent driving, capturing the stochastic interactions within and between filaments. By employing a pair approximation and local equilibrium reasoning, we derive a chemical master equation that describes the system's probabilistic evolution in terms of the length and composition. To uncover the macroscopic dynamics, we apply WKB analysis and use Filippov theory to analyse the resultant piecewise continuous ODEs that describe the evolution of the most probable paths. This analysis allows us to construct a dynamical phase diagram, revealing distinct regimes of behaviour, including dissipative limit cycles that underlie the observed macroscopic fluctuations in microtubule length.

Keywords: WKB Analysis; Filippov Theory; Self-assembly; Many-body physics; Nonequilibrium thermodynamics