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Main Authors: Lasser, Caroline, Lunowa, Stephan B., Wohlmuth, Barbara
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2602.04644
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author Lasser, Caroline
Lunowa, Stephan B.
Wohlmuth, Barbara
author_facet Lasser, Caroline
Lunowa, Stephan B.
Wohlmuth, Barbara
contents We establish rigorously the equivalence between classical moment closure and a nonlinear variational approximation of the Fokker-Planck equation for dilute polymeric flow in the linearized Hookean spring chain setting. The variational formulation is based on the Dirac-Frankel principle applied to a Gaussian approximation manifold endowed with the Fisher-Rao information metric. We show that the invariance of this manifold under the linear configurational dynamics yields an exact evolution for the macroscopic conformation tensor, recovering the classical diffusive Oldroyd-B closure. While the equivalence only holds in the linearized setting, the associated variational framework provides an abstract error representation and a starting point for the systematic construction of reduced approximation schemes for polymeric flows with nonlinear forcing laws.
format Preprint
id arxiv_https___arxiv_org_abs_2602_04644
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle An equivalence of moment closure and nonlinear variational approximation of the Fokker-Planck equation for dilute polymeric flow
Lasser, Caroline
Lunowa, Stephan B.
Wohlmuth, Barbara
Spectral Theory
Mathematical Physics
37L65, 58E30, 35Q84, 76D05
We establish rigorously the equivalence between classical moment closure and a nonlinear variational approximation of the Fokker-Planck equation for dilute polymeric flow in the linearized Hookean spring chain setting. The variational formulation is based on the Dirac-Frankel principle applied to a Gaussian approximation manifold endowed with the Fisher-Rao information metric. We show that the invariance of this manifold under the linear configurational dynamics yields an exact evolution for the macroscopic conformation tensor, recovering the classical diffusive Oldroyd-B closure. While the equivalence only holds in the linearized setting, the associated variational framework provides an abstract error representation and a starting point for the systematic construction of reduced approximation schemes for polymeric flows with nonlinear forcing laws.
title An equivalence of moment closure and nonlinear variational approximation of the Fokker-Planck equation for dilute polymeric flow
topic Spectral Theory
Mathematical Physics
37L65, 58E30, 35Q84, 76D05
url https://arxiv.org/abs/2602.04644