Jacobian determinant as a deformation field in static billiards

Fuente: arXiv
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Main Authors: da Fonseca, Anne Kétri P., Livorati, André L. P., Medrano-T, Rene O., Oliveira, Diego F. M., Leonel, Edson D.
Format: Preprint
Published: 2026
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author da Fonseca, Anne Kétri P.
Livorati, André L. P.
Medrano-T, Rene O.
Oliveira, Diego F. M.
Leonel, Edson D.
author_facet da Fonseca, Anne Kétri P.
Livorati, André L. P.
Medrano-T, Rene O.
Oliveira, Diego F. M.
Leonel, Edson D.
contents We develop a deformation-based framework for analyzing static billiard systems through the Jacobian determinant computed in noncanonical angular coordinates. Although these systems are conservative, the determinant is not identically equal to unity, generating structured domains of local phase-space expansion and contraction. We show numerically that these domains balance globally, providing a geometric manifestation of area preservation in noncanonical variables. The curves defined by det J = 1 act as deformation boundaries that intersect unstable periodic points and correlate with invariant manifolds. We prove analytically that period-two orbits restore exact unit determinant under composition, while higher-period orbits exhibit angular modulation consistent with reversibility. The Jacobian determinant thus reveals an additional geometric layer in phase-space organization and offers a complementary perspective on conservative billiard dynamics.
format Preprint
id arxiv_https___arxiv_org_abs_2603_07767
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Jacobian determinant as a deformation field in static billiards
da Fonseca, Anne Kétri P.
Livorati, André L. P.
Medrano-T, Rene O.
Oliveira, Diego F. M.
Leonel, Edson D.
Chaotic Dynamics
We develop a deformation-based framework for analyzing static billiard systems through the Jacobian determinant computed in noncanonical angular coordinates. Although these systems are conservative, the determinant is not identically equal to unity, generating structured domains of local phase-space expansion and contraction. We show numerically that these domains balance globally, providing a geometric manifestation of area preservation in noncanonical variables. The curves defined by det J = 1 act as deformation boundaries that intersect unstable periodic points and correlate with invariant manifolds. We prove analytically that period-two orbits restore exact unit determinant under composition, while higher-period orbits exhibit angular modulation consistent with reversibility. The Jacobian determinant thus reveals an additional geometric layer in phase-space organization and offers a complementary perspective on conservative billiard dynamics.
title Jacobian determinant as a deformation field in static billiards
topic Chaotic Dynamics
url https://arxiv.org/abs/2603.07767