Geometry of Almost-Conserved Quantities in Symplectic Maps. Part I: Perturbation Theory

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Hauptverfasser: Zolkin, Tim, Nagaitsev, Sergei, Morozov, Ivan, Kladov, Sergei
Format: Preprint
Veröffentlicht: 2025
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author Zolkin, Tim
Nagaitsev, Sergei
Morozov, Ivan
Kladov, Sergei
author_facet Zolkin, Tim
Nagaitsev, Sergei
Morozov, Ivan
Kladov, Sergei
contents Noether's theorem, which connects continuous symmetries to exact conservation laws, remains one of the most fundamental principles in physics and dynamical systems. In this work, we draw a conceptual parallel between two paradigms: the emergence of exact invariants from continuous symmetries, and the appearance of approximate invariants from discrete symmetries associated with reversibility in symplectic maps. We demonstrate that by constructing approximating functions that preserve these discrete symmetries order by order, one can systematically uncover hidden structures, closely echoing Noether's framework. The resulting functions serve not only as diagnostic tools but also as compact representations of near-integrable behavior. The first article establishes the formal foundations of the method. Using the symmetric form of the map as a flexible test case, we benchmark the perturbative construction against established techniques, including the Lie algebra method for twist coefficients. To resolve the inherent ambiguity in the perturbation series, we introduce an averaging procedure that naturally leads to a resonant theory -- capable of treating rational rotation numbers and small-denominator divergences. This enables an accurate and structured description of low-order resonances, including singular and non-singular features in the quadratic and cubic Hénon maps. The approach is systematic, requiring only linear algebra and integrals of elementary functions, yet it yields results in striking agreement with both theory and numerical experiment. We conclude by outlining extensions to more general maps and discussing implications for stability estimates in practical systems such as particle accelerators.
format Preprint
id arxiv_https___arxiv_org_abs_2505_07223
institution arXiv
publishDate 2025
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spellingShingle Geometry of Almost-Conserved Quantities in Symplectic Maps. Part I: Perturbation Theory
Zolkin, Tim
Nagaitsev, Sergei
Morozov, Ivan
Kladov, Sergei
Chaotic Dynamics
Pattern Formation and Solitons
Accelerator Physics
Applied Physics
Noether's theorem, which connects continuous symmetries to exact conservation laws, remains one of the most fundamental principles in physics and dynamical systems. In this work, we draw a conceptual parallel between two paradigms: the emergence of exact invariants from continuous symmetries, and the appearance of approximate invariants from discrete symmetries associated with reversibility in symplectic maps. We demonstrate that by constructing approximating functions that preserve these discrete symmetries order by order, one can systematically uncover hidden structures, closely echoing Noether's framework. The resulting functions serve not only as diagnostic tools but also as compact representations of near-integrable behavior. The first article establishes the formal foundations of the method. Using the symmetric form of the map as a flexible test case, we benchmark the perturbative construction against established techniques, including the Lie algebra method for twist coefficients. To resolve the inherent ambiguity in the perturbation series, we introduce an averaging procedure that naturally leads to a resonant theory -- capable of treating rational rotation numbers and small-denominator divergences. This enables an accurate and structured description of low-order resonances, including singular and non-singular features in the quadratic and cubic Hénon maps. The approach is systematic, requiring only linear algebra and integrals of elementary functions, yet it yields results in striking agreement with both theory and numerical experiment. We conclude by outlining extensions to more general maps and discussing implications for stability estimates in practical systems such as particle accelerators.
title Geometry of Almost-Conserved Quantities in Symplectic Maps. Part I: Perturbation Theory
topic Chaotic Dynamics
Pattern Formation and Solitons
Accelerator Physics
Applied Physics
url https://arxiv.org/abs/2505.07223