Contactifications: a Lagrangian description of compact Hamiltonian systems

Fuente: arXiv
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Autores principales: Grabowska, Katarzyna, Grabowski, Janusz, Kuś, Marek, Marmo, Giuseppe
Formato: Preprint
Publicado: 2024
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author Grabowska, Katarzyna
Grabowski, Janusz
Kuś, Marek
Marmo, Giuseppe
author_facet Grabowska, Katarzyna
Grabowski, Janusz
Kuś, Marek
Marmo, Giuseppe
contents If $η$ is a contact form on a manifold $M$ such that the orbits of the Reeb vector field form a simple foliation $\mathcal{F}$ on $M$, then the presymplectic 2-form $dη$ on $M$ induces a symplectic structure $ω$ on the quotient manifold $N=M/\mathcal{F}$. We call $(M,η)$ a $\textit contactification$ of the symplectic manifold $(N,ω)$. First, we present an explicit geometric construction of contactifications of some coadjoint orbits of connected Lie groups. Our construction is a far going generalization of the well-known contactification of the complex projective space $\mathbb{C}P^{n-1}$, being the unit sphere $S^{2n-1}$ in $\mathbb{C}^{n}$, and equipped with the restriction of the Liouville 1-form on $\mathbb{C}^n$. Second, we describe a constructive procedure for obtaining contactification in the process of the Marsden-Weinstein-Meyer symplectic reduction and indicate geometric obstructions for the existence of compact contactifications. Third, we show that contactifications provide a nice geometrical tool for a Lagrangian description of Hamiltonian systems on compact symplectic manifolds $(N,ω)$, on which symplectic forms never admit a `vector potential'.
format Preprint
id arxiv_https___arxiv_org_abs_2404_19560
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Contactifications: a Lagrangian description of compact Hamiltonian systems
Grabowska, Katarzyna
Grabowski, Janusz
Kuś, Marek
Marmo, Giuseppe
Symplectic Geometry
Mathematical Physics
53D05, 53D10 (Primary) 53D35, 70Hxx, 70H25, 70S05 (Secondary)
If $η$ is a contact form on a manifold $M$ such that the orbits of the Reeb vector field form a simple foliation $\mathcal{F}$ on $M$, then the presymplectic 2-form $dη$ on $M$ induces a symplectic structure $ω$ on the quotient manifold $N=M/\mathcal{F}$. We call $(M,η)$ a $\textit contactification$ of the symplectic manifold $(N,ω)$. First, we present an explicit geometric construction of contactifications of some coadjoint orbits of connected Lie groups. Our construction is a far going generalization of the well-known contactification of the complex projective space $\mathbb{C}P^{n-1}$, being the unit sphere $S^{2n-1}$ in $\mathbb{C}^{n}$, and equipped with the restriction of the Liouville 1-form on $\mathbb{C}^n$. Second, we describe a constructive procedure for obtaining contactification in the process of the Marsden-Weinstein-Meyer symplectic reduction and indicate geometric obstructions for the existence of compact contactifications. Third, we show that contactifications provide a nice geometrical tool for a Lagrangian description of Hamiltonian systems on compact symplectic manifolds $(N,ω)$, on which symplectic forms never admit a `vector potential'.
title Contactifications: a Lagrangian description of compact Hamiltonian systems
topic Symplectic Geometry
Mathematical Physics
53D05, 53D10 (Primary) 53D35, 70Hxx, 70H25, 70S05 (Secondary)
url https://arxiv.org/abs/2404.19560