dorsal/arxiv
View SchemaSymplectic mechanics of relativistic spinning compact bodies. III. quadratic-in-spin integrability in Type-D Einstein spacetimes: persistence and breakdown
| Authors | Paul Ramond, Soichiro Isoyama, Adrien Druart |
|---|---|
| Categories | |
| ArXiv ID | 2601.06416vv1 |
| URL | https://arxiv.org/abs/2601.06416 |
| License | http://creativecommons.org/licenses/by/4.0/ |
Abstract
We develop a covariant Hamiltonian formulation of the Mathisson-Papapetrou-Tulczyjew-Dixon dynamics at quadratic order in spin under the Tulczyjew-Dixon spin supplementary condition (TD SSC). In four-dimensional, type-D Einstein (vacuum/$\Lambda$-vacuum) spacetimes admitting a non-degenerate Killing-Yano (KY) tensor, we reduce via a Dirac bracket to the 10-dimensional physical phase space and model the quadratic sector with a spin-induced quadrupole characterized by a deformability $\kappa$ ($\kappa=1$ for black-hole--like; $\kappa\neq 1$ for material or exotic compact objects). For $\kappa=1$, we construct five independent first integrals -- an autonomous Hamiltonian, two KY-generated Killing invariants, a linear R\"udiger constant, and a quadratic Carter-R\"udiger constant -- establishing Liouville-Arnold integrability at quadratic order in spin. For $\kappa\neq 1$, the symmetry-generated invariants are not conserved in general and integrability does not persist at this order. The proof proceeds via covariant Poisson-bracket computations using a null bivector decomposition; Kerr is recovered as a special case. These results show that integrability can persist beyond Kerr and beyond the linear-in-spin regime, laying groundwork for symmetry-based, beyond-Kerr modelling of asymmetric-mass, spinning compact binaries.
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"abstract": "We develop a covariant Hamiltonian formulation of the Mathisson-Papapetrou-Tulczyjew-Dixon dynamics at quadratic order in spin under the Tulczyjew-Dixon spin supplementary condition (TD SSC). In four-dimensional, type-D Einstein (vacuum/$\\Lambda$-vacuum) spacetimes admitting a non-degenerate Killing-Yano (KY) tensor, we reduce via a Dirac bracket to the 10-dimensional physical phase space and model the quadratic sector with a spin-induced quadrupole characterized by a deformability $\\kappa$ ($\\kappa=1$ for black-hole--like; $\\kappa\\neq 1$ for material or exotic compact objects). For $\\kappa=1$, we construct five independent first integrals -- an autonomous Hamiltonian, two KY-generated Killing invariants, a linear R\\\"udiger constant, and a quadratic Carter-R\\\"udiger constant -- establishing Liouville-Arnold integrability at quadratic order in spin. For $\\kappa\\neq 1$, the symmetry-generated invariants are not conserved in general and integrability does not persist at this order. The proof proceeds via covariant Poisson-bracket computations using a null bivector decomposition; Kerr is recovered as a special case. These results show that integrability can persist beyond Kerr and beyond the linear-in-spin regime, laying groundwork for symmetry-based, beyond-Kerr modelling of asymmetric-mass, spinning compact binaries.",
"arxiv_id": "2601.06416",
"authors": [
"Paul Ramond",
"Soichiro Isoyama",
"Adrien Druart"
],
"categories": [
"gr-qc",
"nlin.SI"
],
"license": "http://creativecommons.org/licenses/by/4.0/",
"title": "Symplectic mechanics of relativistic spinning compact bodies. III. quadratic-in-spin integrability in Type-D Einstein spacetimes: persistence and breakdown",
"url": "https://arxiv.org/abs/2601.06416",
"version": "v1"
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