Numerical solutions for the $f(R)$-Klein-Gordon system

Fuente: arXiv
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Autores principales: Vinckers, Ulrich K. Beckering, de la Cruz-Dombriz, Álvaro, Pollney, Denis
Formato: Preprint
Publicado: 2023
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author Vinckers, Ulrich K. Beckering
de la Cruz-Dombriz, Álvaro
Pollney, Denis
author_facet Vinckers, Ulrich K. Beckering
de la Cruz-Dombriz, Álvaro
Pollney, Denis
contents We construct a numerical relativity code based on the Baumgarte-Shapiro-Shibata-Nakamura (BSSN) formulation for the gravitational quadratic $f(R)$ Starobinsky model. By removing the assumption that the determinant of the conformal 3-metric is unity, we first generalize the BSSN formulation for general $f(R)$ gravity theories in the metric formalism to accommodate arbitrary coordinates for the first time. We then describe the implementation of this formalism to the paradigmatic Starobinsky model. We apply the implementation to three scenarios: the Schwarzschild black hole solution, flat space with non-trivial gauge dynamics, and a massless Klein-Gordon scalar field. In each case, long-term stability and second-order convergence is demonstrated. The case of the massless Klein-Gordon scalar field is used to exercise the additional terms and variables resulting from the $f(R)$ contributions. For this model, we show for the first time that additional damped oscillations arise in the subcritical regime as the system approaches a stable configuration.
format Preprint
id arxiv_https___arxiv_org_abs_2304_03794
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Numerical solutions for the $f(R)$-Klein-Gordon system
Vinckers, Ulrich K. Beckering
de la Cruz-Dombriz, Álvaro
Pollney, Denis
General Relativity and Quantum Cosmology
We construct a numerical relativity code based on the Baumgarte-Shapiro-Shibata-Nakamura (BSSN) formulation for the gravitational quadratic $f(R)$ Starobinsky model. By removing the assumption that the determinant of the conformal 3-metric is unity, we first generalize the BSSN formulation for general $f(R)$ gravity theories in the metric formalism to accommodate arbitrary coordinates for the first time. We then describe the implementation of this formalism to the paradigmatic Starobinsky model. We apply the implementation to three scenarios: the Schwarzschild black hole solution, flat space with non-trivial gauge dynamics, and a massless Klein-Gordon scalar field. In each case, long-term stability and second-order convergence is demonstrated. The case of the massless Klein-Gordon scalar field is used to exercise the additional terms and variables resulting from the $f(R)$ contributions. For this model, we show for the first time that additional damped oscillations arise in the subcritical regime as the system approaches a stable configuration.
title Numerical solutions for the $f(R)$-Klein-Gordon system
topic General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2304.03794