An amplitude equation for the conserved-Hopf bifurcation -- derivation, analysis and assessment

Fuente: arXiv
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Main Authors: Greve, Daniel, Thiele, Uwe
Format: Preprint
Published: 2024
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author Greve, Daniel
Thiele, Uwe
author_facet Greve, Daniel
Thiele, Uwe
contents We employ weakly nonlinear theory to derive an amplitude equation for the conserved-Hopf instability, i.e., a generic large-scale oscillatory instability for systems with two conservation laws. The resulting equation represents in the conserved case the equivalent of the complex Ginzburg-Landau equation obtained in the nonconserved case as amplitude equation for the standard Hopf bifurcation.Considering first the case of a relatively simple symmetric Cahn-Hilliard model with purely nonreciprocal coupling, we derive the nonlinear nonlocal amplitude equation with real coefficients and show that its bifurcation diagram and time evolution well agree with results for the full model. The solutions of the amplitude equation and their stability are analytically obtained thereby showing that in oscillatory phase separation the suppression of coarsening is universal. Second, we lift the two restrictions and obtain the amplitude equation in the generic case that has complex coefficients, that also shows very good agreement with the full model as exemplified for some transient dynamics that converges to traveling wave states.
format Preprint
id arxiv_https___arxiv_org_abs_2407_03670
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle An amplitude equation for the conserved-Hopf bifurcation -- derivation, analysis and assessment
Greve, Daniel
Thiele, Uwe
Pattern Formation and Solitons
We employ weakly nonlinear theory to derive an amplitude equation for the conserved-Hopf instability, i.e., a generic large-scale oscillatory instability for systems with two conservation laws. The resulting equation represents in the conserved case the equivalent of the complex Ginzburg-Landau equation obtained in the nonconserved case as amplitude equation for the standard Hopf bifurcation.Considering first the case of a relatively simple symmetric Cahn-Hilliard model with purely nonreciprocal coupling, we derive the nonlinear nonlocal amplitude equation with real coefficients and show that its bifurcation diagram and time evolution well agree with results for the full model. The solutions of the amplitude equation and their stability are analytically obtained thereby showing that in oscillatory phase separation the suppression of coarsening is universal. Second, we lift the two restrictions and obtain the amplitude equation in the generic case that has complex coefficients, that also shows very good agreement with the full model as exemplified for some transient dynamics that converges to traveling wave states.
title An amplitude equation for the conserved-Hopf bifurcation -- derivation, analysis and assessment
topic Pattern Formation and Solitons
url https://arxiv.org/abs/2407.03670