Time-changed reflected diffusions: subdiffusion, superdiffusion and explosion
Abstract
Motivated by semi-Markov models of anomalous diffusion, we study obliquely reflected diffusions in generalized parabolic domains under independent inverse-subordinator time changes. We focus on infinite-mean subordinators, whose inverse clocks can slow the superdiffusive growth induced by reflection. For domains with cross-sectional radius asymptotic to a∞ xβ, where −1<β<1, we strengthen the almost-sure growth laws of [MMW23] to obtain precise second-moment asymptotics when the subordinator's Laplace exponent is regularly varying at zero, and matching bounds more generally. Inverse α-stable clocks yield mean-square growth of order t2α/(1+β), giving subdiffusive, diffusive, or superdiffusive regimes. For β<−1, explosion persists almost surely, with finite mean explosion time if and only if the subordinator has finite mean. Supporting results establish strong existence, pathwise uniqueness, and a time-change representation, also allowing dependent clocks.
Related
- Limit theorems for one-dimensional diffusions: reflected, skew, sticky, skew-sticky, and snapping-out limits
- Numerical Integration on Bounded Domains via Learned Reflected Diffusions
- Corrected L1 Scheme for the Fractional Subdiffusion Equation
- Numerical methods for nonlinear stochastic differential equations driven by subdiffusion
- Error analysis of a backward L2 method on graded meshes for linear and semilinear subdiffusion equations
BibTeX
@misc{mijatovic2026timechanged,
title = {{Time-changed reflected diffusions: subdiffusion, superdiffusion and explosion}},
author = {Aleksandar Mijatović and Francesco Virgili},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.13302},
eprint = {2610.13302},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.13302},
}
RIS
TY - UNPB
TI - Time-changed reflected diffusions: subdiffusion, superdiffusion and explosion
AU - Aleksandar Mijatović
AU - Francesco Virgili
PY - 2026
DA - 2026/10/09
PB - arXiv
DO - 10.48550/arxiv.2610.13302
UR - https://arxiv.org/abs/2610.13302
AB - Motivated by semi-Markov models of anomalous diffusion, we study obliquely reflected diffusions in generalized parabolic domains under independent inverse-subordinator time changes. We focus on infinite-mean subordinators, whose inverse clocks can slow the superdiffusive growth induced by reflection. For domains with cross-sectional radius asymptotic to a_∞ x^β, where −1<β<1, we strengthen the almost-sure growth laws of [MMW23] to obtain precise second-moment asymptotics when the subordinator's Laplace exponent is regularly varying at zero, and matching bounds more generally. Inverse α-stable clocks yield mean-square growth of order t^2α/(1+β), giving subdiffusive, diffusive, or superdiffusive regimes. For β<−1, explosion persists almost surely, with finite mean explosion time if and only if the subordinator has finite mean. Supporting results establish strong existence, pathwise uniqueness, and a time-change representation, also allowing dependent clocks.
ER -