A Differentiable Parametric Model of Binary-Black-Hole Initial Data: I. Conformally flat Bowen-York punctures
Abstract
Constraint-satisfying initial data for binary black holes require the repeated solution of a nonlinear elliptic boundary-value problem throughout the physical parameter space. We present a para\-metric, differentiable initial-data model that combines sparse-grid spectral interpolation with Newton refinement over a family of binary configurations. Interpolation is used only to provide warm starts for the underlying elliptic solver, rather than to replace it. A small number of Newton iterations refines each interpolated solution to a discrete, row-equilibrated constraint residual |R|∞≤10−10, independent of the interpolation error, so that every returned initial-data set satisfies the discretized constraint to that tolerance. Our JAX implementation provides analytic derivatives with respect to the physical parameters, enabling gradient-based parameter targeting, optimization, and sensitivity analysis. We demonstrate the method for quasi-circular binary-black-hole initial data using conformally flat Bowen--York punctures by constructing four-dimensional aligned-spin and eight-dimensional general-spin models. The resulting initial data are validated against TwoPunctures, and the method is applied to certified targeting of the physical Arnowitt--Deser--Misner mass and angular momentum and to effective-potential eccentricity reduction using a dedicated separation--tangential-momentum model.
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BibTeX
@misc{ceuster2026differentiable,
title = {{A Differentiable Parametric Model of Binary-Black-Hole Initial Data: I. Conformally flat Bowen-York punctures}},
author = {Frederik De Ceuster and Tjonnie G. -F. Li},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.10173},
eprint = {2609.10173},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.10173},
}
RIS
TY - UNPB
TI - A Differentiable Parametric Model of Binary-Black-Hole Initial Data: I. Conformally flat Bowen-York punctures
AU - Frederik De Ceuster
AU - Tjonnie G. -F. Li
PY - 2026
DA - 2026/09/09
PB - arXiv
DO - 10.48550/arxiv.2609.10173
UR - https://arxiv.org/abs/2609.10173
AB - Constraint-satisfying initial data for binary black holes require the repeated solution of a nonlinear elliptic boundary-value problem throughout the physical parameter space. We present a para\-metric, differentiable initial-data model that combines sparse-grid spectral interpolation with Newton refinement over a family of binary configurations. Interpolation is used only to provide warm starts for the underlying elliptic solver, rather than to replace it. A small number of Newton iterations refines each interpolated solution to a discrete, row-equilibrated constraint residual |R|_∞≤10^−10, independent of the interpolation error, so that every returned initial-data set satisfies the discretized constraint to that tolerance. Our JAX implementation provides analytic derivatives with respect to the physical parameters, enabling gradient-based parameter targeting, optimization, and sensitivity analysis. We demonstrate the method for quasi-circular binary-black-hole initial data using conformally flat Bowen--York punctures by constructing four-dimensional aligned-spin and eight-dimensional general-spin models. The resulting initial data are validated against TwoPunctures, and the method is applied to certified targeting of the physical Arnowitt--Deser--Misner mass and angular momentum and to effective-potential eccentricity reduction using a dedicated separation--tangential-momentum model.
ER -