Optimal error bounds on the exponential integrator for dispersive equations with highly concentrated potential

Fuente: arXiv
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Auteurs principaux: Bal, Guillaume, Wang, Chushan
Format: Preprint
Publié: 2026
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author Bal, Guillaume
Wang, Chushan
author_facet Bal, Guillaume
Wang, Chushan
contents We study a one-dimensional linear dispersive equation of differential order $κ\geq 2$ with concentrated potential of extension $\varepsilon$ with $0 < \varepsilon \ll 1$, featuring a competition between weak dispersion of strength $\varepsilon^α\ (0 \leq α\leq κ)$ and localization induced by the concentrated potential. We first obtain precise regularity estimates of the exact solution in terms of $\varepsilon$. We then apply a natural first-order exponential integrator with step size $τ$ to discretize the equation, and establish an optimal error bound of the form $O_{L^\infty}(τ\varepsilon^β)$ (up to logarithmic factors in $τ$ and $\varepsilon$). Salient features of the result are: (i) error bounds are not only uniform in $\varepsilon$ but improve as $\varepsilon \rightarrow 0$; and (ii) no restriction on $τ$ in terms of $\varepsilon$. The analysis combines iterated Duhamel's expansions and a transformation that exploits cancellations in oscillatory phases that cannot be obtained directly from regularity estimates of the exact solution. We also show that other classical numerical schemes, such as Lie or centered splitting schemes and low regularity integrators, fail to display optimal rates of convergence. Extensive numerical results are presented and confirm the theoretical error estimates.
format Preprint
id arxiv_https___arxiv_org_abs_2602_22068
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Optimal error bounds on the exponential integrator for dispersive equations with highly concentrated potential
Bal, Guillaume
Wang, Chushan
Numerical Analysis
65M15, 35Q55, 65M70, 35R60
We study a one-dimensional linear dispersive equation of differential order $κ\geq 2$ with concentrated potential of extension $\varepsilon$ with $0 < \varepsilon \ll 1$, featuring a competition between weak dispersion of strength $\varepsilon^α\ (0 \leq α\leq κ)$ and localization induced by the concentrated potential. We first obtain precise regularity estimates of the exact solution in terms of $\varepsilon$. We then apply a natural first-order exponential integrator with step size $τ$ to discretize the equation, and establish an optimal error bound of the form $O_{L^\infty}(τ\varepsilon^β)$ (up to logarithmic factors in $τ$ and $\varepsilon$). Salient features of the result are: (i) error bounds are not only uniform in $\varepsilon$ but improve as $\varepsilon \rightarrow 0$; and (ii) no restriction on $τ$ in terms of $\varepsilon$. The analysis combines iterated Duhamel's expansions and a transformation that exploits cancellations in oscillatory phases that cannot be obtained directly from regularity estimates of the exact solution. We also show that other classical numerical schemes, such as Lie or centered splitting schemes and low regularity integrators, fail to display optimal rates of convergence. Extensive numerical results are presented and confirm the theoretical error estimates.
title Optimal error bounds on the exponential integrator for dispersive equations with highly concentrated potential
topic Numerical Analysis
65M15, 35Q55, 65M70, 35R60
url https://arxiv.org/abs/2602.22068