🤖 AI Summary
This work addresses eigenfunction problems with unknown eigenvalues—such as quasi-stationary distributions and ergodic stochastic control in non-conservative systems—where conventional methods are restricted to cases with known eigenvalues (e.g., zero). We propose a novel particle exchange Monte Carlo method that overcomes this limitation. Our core innovation is a time-symmetric forward–backward coupled stochastic process framework, enabling the first particle exchange mechanism explicitly designed for eigenvalue-agnostic settings. The method jointly estimates both the eigenfunction and its associated eigenvalue without requiring prior knowledge of the eigenvalue. Numerical experiments demonstrate substantial improvements in convergence speed and numerical stability for high-dimensional non-conservative systems. By eliminating eigenvalue pre-specification, our approach establishes a scalable and robust computational paradigm for eigenproblems in complex stochastic dynamical systems.
📝 Abstract
We introduce and develop a novel particle exchange Monte Carlo method. Whereas existing methods apply to eigenfunction problems where the eigenvalue is known (e.g., integrals with respect to a Gibbs measure, which can be interpreted as corresponding to eigenvalue zero), here the focus is on problems where the eigenvalue is not known a priori. To obtain an appropriate particle exchange rule we must consider a pair of processes, with one evolving forward in time and the other backward. Applications to eigenfunction problems corresponding to quasistationary distributions and ergodic stochastic control are discussed.