A bifurcation theory approach to the nonlocal Kuramoto-Sivashinsky equation

Fuente: arXiv
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Autores principales: Cubillos, Pablo, Granero-Belinchón, Rafael, Sampedro, Juan Carlos
Formato: Preprint
Publicado: 2026
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author Cubillos, Pablo
Granero-Belinchón, Rafael
Sampedro, Juan Carlos
author_facet Cubillos, Pablo
Granero-Belinchón, Rafael
Sampedro, Juan Carlos
contents We study the nonlocal Kuramoto-Sivashinsky equation on the one-dimensional torus, \[ u_t+u u_x=Λ^{r}u-\varepsilon Λ^{s}u,\qquad x\in\mathbb T, \] where $\varepsilon>0$, $s>1$, $r\in[-1,s)$. We first prove local and global well-posedness for initial data in $H^{3}(\mathbb T)$. We then investigate the steady-state problem and show that the trivial branch undergoes bifurcation at the critical values $\varepsilon_k=k^{\,r-s}$, $k\in\mathbb N$. Using the Crandall-Rabinowitz theorem we obtain smooth local curves of nontrivial equilibria emanating from each $(\varepsilon_k,0)$ and compute the bifurcation direction. To address the global continuation of these branches we derive global a priori bounds and apply a global alternative based on the Fitzpatrick-Pejsachowicz-Rabier degree for Fredholm maps of index zero. In particular, for the component bifurcating from the first critical point we prove that its $\varepsilon$-projection contains the interval $(2^{r-s},1)$, yielding the existence of nontrivial steady states for that parameter range. We complement the theory with numerical continuation results illustrating the bifurcation diagram and solution profiles.
format Preprint
id arxiv_https___arxiv_org_abs_2602_08107
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle A bifurcation theory approach to the nonlocal Kuramoto-Sivashinsky equation
Cubillos, Pablo
Granero-Belinchón, Rafael
Sampedro, Juan Carlos
Analysis of PDEs
35B10, 35S15, 35S05, 47J15, 47A53
We study the nonlocal Kuramoto-Sivashinsky equation on the one-dimensional torus, \[ u_t+u u_x=Λ^{r}u-\varepsilon Λ^{s}u,\qquad x\in\mathbb T, \] where $\varepsilon>0$, $s>1$, $r\in[-1,s)$. We first prove local and global well-posedness for initial data in $H^{3}(\mathbb T)$. We then investigate the steady-state problem and show that the trivial branch undergoes bifurcation at the critical values $\varepsilon_k=k^{\,r-s}$, $k\in\mathbb N$. Using the Crandall-Rabinowitz theorem we obtain smooth local curves of nontrivial equilibria emanating from each $(\varepsilon_k,0)$ and compute the bifurcation direction. To address the global continuation of these branches we derive global a priori bounds and apply a global alternative based on the Fitzpatrick-Pejsachowicz-Rabier degree for Fredholm maps of index zero. In particular, for the component bifurcating from the first critical point we prove that its $\varepsilon$-projection contains the interval $(2^{r-s},1)$, yielding the existence of nontrivial steady states for that parameter range. We complement the theory with numerical continuation results illustrating the bifurcation diagram and solution profiles.
title A bifurcation theory approach to the nonlocal Kuramoto-Sivashinsky equation
topic Analysis of PDEs
35B10, 35S15, 35S05, 47J15, 47A53
url https://arxiv.org/abs/2602.08107