dorsal/arxiv
View SchemaDerivation and Analysis of Amplitude Equation for Generalized AMB+ in Presence of Chemical Reaction
| Authors | Sayantan Mondal, Prasenjit Das |
|---|---|
| Categories | |
| ArXiv ID | 2601.07231vv1 |
| URL | https://arxiv.org/abs/2601.07231 |
| License | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ |
Abstract
We derive and analyze the amplitude equation for the roll patterns in case of generalized Active Model B+ (AMB+) in the presence of chemical reactions. The generalized AMB+ differs from the original AMB+ introduced by Tjhung \textit{et al.} [E. Tjhung \textit{et al.}, Phys. Rev. X \textbf{8}, 031080 (2018)] by the addition of a quadratic term, $g\phi^2$, in the expression for the equilibrium part of the current. Also, the model includes a rotation-free active current of strength $\lambda$ and a rotational current of strength $\xi$. The inclusion of a chemical reaction with rate $\Gamma$ removes the conservation constraint and introduces a preferred wavenumber that governs the pattern formation below a critical reaction rate $\Gamma_c$. We argue for the analytical form of the amplitude equation based on symmetry considerations and explicitly derived it using multiscale analysis. By taking different limits of $g$, $\lambda$, and $\xi$, we recover amplitude equations for several well-known physical models as special cases and determine the nature transitions close to the onset of instability. We find that for $g = 0$, the transition is always supercritical, whereas for $g \ne 0$, the transition between the supercritical and subcritical regimes depends sensitively on the model parameters. Further, we derive the condition for the \textit{Eckhaus instability} from the stability analysis of the amplitude equation as well as from the phase diffusion equation, and find that it is independent of $g$.
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"abstract": "We derive and analyze the amplitude equation for the roll patterns in case of generalized Active Model B+ (AMB+) in the presence of chemical reactions. The generalized AMB+ differs from the original AMB+ introduced by Tjhung \\textit{et al.} [E. Tjhung \\textit{et al.}, Phys. Rev. X \\textbf{8}, 031080 (2018)] by the addition of a quadratic term, $g\\phi^2$, in the expression for the equilibrium part of the current. Also, the model includes a rotation-free active current of strength $\\lambda$ and a rotational current of strength $\\xi$. The inclusion of a chemical reaction with rate $\\Gamma$ removes the conservation constraint and introduces a preferred wavenumber that governs the pattern formation below a critical reaction rate $\\Gamma_c$. We argue for the analytical form of the amplitude equation based on symmetry considerations and explicitly derived it using multiscale analysis. By taking different limits of $g$, $\\lambda$, and $\\xi$, we recover amplitude equations for several well-known physical models as special cases and determine the nature transitions close to the onset of instability. We find that for $g = 0$, the transition is always supercritical, whereas for $g \\ne 0$, the transition between the supercritical and subcritical regimes depends sensitively on the model parameters. Further, we derive the condition for the \\textit{Eckhaus instability} from the stability analysis of the amplitude equation as well as from the phase diffusion equation, and find that it is independent of $g$.",
"arxiv_id": "2601.07231",
"authors": [
"Sayantan Mondal",
"Prasenjit Das"
],
"categories": [
"cond-mat.stat-mech",
"cond-mat.soft"
],
"license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
"title": "Derivation and Analysis of Amplitude Equation for Generalized AMB+ in Presence of Chemical Reaction",
"url": "https://arxiv.org/abs/2601.07231",
"version": "v1"
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