Special Session 176: Non-local Stochastic Evolutionary Systems: Theory and Applications

Intrinsic vs. Extrinsic Noise in Transient Dynamics: A Quasi-Stationary Approach
Weiwei Qi
Academy of Mathematics and Systems Science, CAS
Peoples Rep of China
Co-Author(s):    
Abstract:
Transient dynamics--long-lasting but ultimately finite-time behaviors--are ubiquitous in complex stochastic systems. Understanding their underlying mechanisms remains a fundamental challenge. In this talk, we investigate randomly perturbed processes arising in chemical reaction networks and population dynamics, where extinction is inevitable but preceded by long-lived persistence. Using quasi-stationary distributions (QSDs), we characterize these transient dynamics and analyze their asymptotics in the vanishing-noise regime. We show that intrinsic and extrinsic noise can induce fundamentally different transient dynamics, leading to distinct persistence and extinction patterns. We conclude with a discussion of broader implications and open problems.