Fractional Diffusion on Graphs: Superposition of Laplacian Semigroups and Memory

Fuente: arXiv
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Autores principales: Deniskin, Nikita, Estrada, Ernesto
Formato: Preprint
Publicado: 2026
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author Deniskin, Nikita
Estrada, Ernesto
author_facet Deniskin, Nikita
Estrada, Ernesto
contents Subdiffusion on graphs is often modeled by time-fractional diffusion equations, yet its structural and dynamical consequences remain unclear. We show that subdiffusive transport on graphs is a memory-driven process generated by a random time change that compresses operational time, produces long-tailed waiting times, and breaks Markovianity while preserving linearity and mass conservation. We prove that Mittag-Leffler graph dynamics admit an exact convex, mass-preserving representation as a superposition of classical heat semigroups evaluated at rescaled times, revealing fractional diffusion as ordinary diffusion acting across multiple intrinsic time scales. This framework uncovers heterogeneous, vertex-dependent memory effects and induces transport biases absent in classical diffusion, including algebraic relaxation, degree-dependent waiting times, and early-time asymmetries between sources and neighbors. These features define a subdiffusive geometry on graphs enabling particles to locally discover global shortest paths while favoring high-degree regions. Finally, we show that time-fractional diffusion arises as a singular limit of multi-rate diffusion.
format Preprint
id arxiv_https___arxiv_org_abs_2601_14977
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Fractional Diffusion on Graphs: Superposition of Laplacian Semigroups and Memory
Deniskin, Nikita
Estrada, Ernesto
Social and Information Networks
Combinatorics
Dynamical Systems
26A33, 15A16, 35R11, 47D06, 45D05
G.2.2
Subdiffusion on graphs is often modeled by time-fractional diffusion equations, yet its structural and dynamical consequences remain unclear. We show that subdiffusive transport on graphs is a memory-driven process generated by a random time change that compresses operational time, produces long-tailed waiting times, and breaks Markovianity while preserving linearity and mass conservation. We prove that Mittag-Leffler graph dynamics admit an exact convex, mass-preserving representation as a superposition of classical heat semigroups evaluated at rescaled times, revealing fractional diffusion as ordinary diffusion acting across multiple intrinsic time scales. This framework uncovers heterogeneous, vertex-dependent memory effects and induces transport biases absent in classical diffusion, including algebraic relaxation, degree-dependent waiting times, and early-time asymmetries between sources and neighbors. These features define a subdiffusive geometry on graphs enabling particles to locally discover global shortest paths while favoring high-degree regions. Finally, we show that time-fractional diffusion arises as a singular limit of multi-rate diffusion.
title Fractional Diffusion on Graphs: Superposition of Laplacian Semigroups and Memory
topic Social and Information Networks
Combinatorics
Dynamical Systems
26A33, 15A16, 35R11, 47D06, 45D05
G.2.2
url https://arxiv.org/abs/2601.14977