Real Forms of Holomorphic Hamiltonian Systems

By complexifying a Hamiltonian system, one obtains dynamics on a holomorphic symplectic manifold. To invert this construction, we present a theory of real forms that not only recovers the original system but also yields different real Hamiltonian systems that share the same complexification. This pr...

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Published in:Symmetry, Integrability and Geometry: Methods and Applications
Date:2024
Main Authors: Arathoon, Philip, Fontaine, Marine
Format: Article
Language:English
Published: Інститут математики НАН України 2024
Online Access:https://nasplib.isofts.kiev.ua/handle/123456789/212778
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Journal Title:Digital Library of Periodicals of National Academy of Sciences of Ukraine
Cite this:Real Forms of Holomorphic Hamiltonian Systems. Philip Arathoon and Marine Fontaine. SIGMA 20 (2024), 114, 24 pages

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Digital Library of Periodicals of National Academy of Sciences of Ukraine
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author Arathoon, Philip
Fontaine, Marine
author_facet Arathoon, Philip
Fontaine, Marine
citation_txt Real Forms of Holomorphic Hamiltonian Systems. Philip Arathoon and Marine Fontaine. SIGMA 20 (2024), 114, 24 pages
collection DSpace DC
container_title Symmetry, Integrability and Geometry: Methods and Applications
description By complexifying a Hamiltonian system, one obtains dynamics on a holomorphic symplectic manifold. To invert this construction, we present a theory of real forms that not only recovers the original system but also yields different real Hamiltonian systems that share the same complexification. This provides a notion of real forms for holomorphic Hamiltonian systems analogous to that of real forms for complex Lie algebras. Our main result is that the complexification of any analytic mechanical system on a Grassmannian admits a real form on a compact symplectic manifold. This produces a 'unitary trick' for Hamiltonian systems, which curiously requires an essential use of hyperkähler geometry. We demonstrate this result by finding compact real forms for the simple pendulum, the spherical pendulum, and the rigid body.
first_indexed 2026-03-15T23:36:29Z
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institution Digital Library of Periodicals of National Academy of Sciences of Ukraine
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language English
last_indexed 2026-03-15T23:36:29Z
publishDate 2024
publisher Інститут математики НАН України
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spelling Arathoon, Philip
Fontaine, Marine
2026-02-11T10:37:23Z
2024
Real Forms of Holomorphic Hamiltonian Systems. Philip Arathoon and Marine Fontaine. SIGMA 20 (2024), 114, 24 pages
1815-0659
2020 Mathematics Subject Classification: 53D20; 14J42
arXiv:2009.10417
https://nasplib.isofts.kiev.ua/handle/123456789/212778
https://doi.org/10.3842/SIGMA.2024.114
By complexifying a Hamiltonian system, one obtains dynamics on a holomorphic symplectic manifold. To invert this construction, we present a theory of real forms that not only recovers the original system but also yields different real Hamiltonian systems that share the same complexification. This provides a notion of real forms for holomorphic Hamiltonian systems analogous to that of real forms for complex Lie algebras. Our main result is that the complexification of any analytic mechanical system on a Grassmannian admits a real form on a compact symplectic manifold. This produces a 'unitary trick' for Hamiltonian systems, which curiously requires an essential use of hyperkähler geometry. We demonstrate this result by finding compact real forms for the simple pendulum, the spherical pendulum, and the rigid body.
At the time of writing, Philip Arathoon was funded by an EPSRC Doctoral Prize Award hosted by the University of Manchester, and Marine Fontaine was supported by the FWO-EoS Project G0H4518N. We would like to extend special thanks to James Montaldi for carefully reading an early draft and for suggesting many helpful comments throughout its preparation. Additional thanks are owed to the referees whose insights and recommendations helped to improve this paper.
en
Інститут математики НАН України
Symmetry, Integrability and Geometry: Methods and Applications
Real Forms of Holomorphic Hamiltonian Systems
Article
published earlier
spellingShingle Real Forms of Holomorphic Hamiltonian Systems
Arathoon, Philip
Fontaine, Marine
title Real Forms of Holomorphic Hamiltonian Systems
title_full Real Forms of Holomorphic Hamiltonian Systems
title_fullStr Real Forms of Holomorphic Hamiltonian Systems
title_full_unstemmed Real Forms of Holomorphic Hamiltonian Systems
title_short Real Forms of Holomorphic Hamiltonian Systems
title_sort real forms of holomorphic hamiltonian systems
url https://nasplib.isofts.kiev.ua/handle/123456789/212778
work_keys_str_mv AT arathoonphilip realformsofholomorphichamiltoniansystems
AT fontainemarine realformsofholomorphichamiltoniansystems