Anisotropic Dark Matter Bosonic Stars in regularized 4D Einstein$-$Gauss$-$Bonnet gravity
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arXiv
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| Format: | Preprint |
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2025
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| _version_ | 1866917026349449216 |
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| author | Mazhari, Mohamamd |
| author_facet | Mazhari, Mohamamd |
| contents | In this work, we have constructed anisotropic bosonic dark-matter star (DMS) solutions in the context of a regularized four-dimensional Einstein$-$Gauss$-$Bonnet (4D EGB) gravity theory. Using dimensional regularization, we solve modified Tolman$-$Oppenheimer$-$Volkoff equations for a self-interacting complex scalar field in the dilute polytropic regime, $p_r = K ρ^2$, with anisotropy parameterized as $σ= β\, p_r \left( 1 - e^{-2λ} \right)$. We perform a comprehensive numerical analysis across the \((α,β)\) parameter domain, where \(α\in [0,8]~\mathrm{km}^2\) and \(β\in [-2,0]\), to examine mass$-$radius relations and evaluate multiple stability indicators including static equilibrium \(dM/dp_c\), sound-speed causality, the radial adiabatic index \(Γ_r\), and energy conditions. Positive Gauss$-$Bonnet coupling enhances both the maximum mass and compactness (e.g., \(M_{\rm max} \approx 1.62\, M_\odot\) at \(α=0\) rising to \(\approx 2.09\, M_\odot\) at \(α= 8~\mathrm{km}^2\)), while negative anisotropy reduces them (e.g., from \(\approx 2.21\, M_\odot\) at \(β=0\) to \(\approx 1.73\, M_\odot\) at \(β= -2\)). The resulting configurations remain statically stable up to the mass peak and satisfy physical criteria. This work extends previous isotropic boson-star analyses by systematically incorporating anisotropy within a regularized 4D EGB framework. These findings provide observationally relevant predictions for compact dark-matter objects under modified gravity. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2510_15549 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Anisotropic Dark Matter Bosonic Stars in regularized 4D Einstein$-$Gauss$-$Bonnet gravity Mazhari, Mohamamd General Relativity and Quantum Cosmology High Energy Astrophysical Phenomena High Energy Physics - Theory In this work, we have constructed anisotropic bosonic dark-matter star (DMS) solutions in the context of a regularized four-dimensional Einstein$-$Gauss$-$Bonnet (4D EGB) gravity theory. Using dimensional regularization, we solve modified Tolman$-$Oppenheimer$-$Volkoff equations for a self-interacting complex scalar field in the dilute polytropic regime, $p_r = K ρ^2$, with anisotropy parameterized as $σ= β\, p_r \left( 1 - e^{-2λ} \right)$. We perform a comprehensive numerical analysis across the \((α,β)\) parameter domain, where \(α\in [0,8]~\mathrm{km}^2\) and \(β\in [-2,0]\), to examine mass$-$radius relations and evaluate multiple stability indicators including static equilibrium \(dM/dp_c\), sound-speed causality, the radial adiabatic index \(Γ_r\), and energy conditions. Positive Gauss$-$Bonnet coupling enhances both the maximum mass and compactness (e.g., \(M_{\rm max} \approx 1.62\, M_\odot\) at \(α=0\) rising to \(\approx 2.09\, M_\odot\) at \(α= 8~\mathrm{km}^2\)), while negative anisotropy reduces them (e.g., from \(\approx 2.21\, M_\odot\) at \(β=0\) to \(\approx 1.73\, M_\odot\) at \(β= -2\)). The resulting configurations remain statically stable up to the mass peak and satisfy physical criteria. This work extends previous isotropic boson-star analyses by systematically incorporating anisotropy within a regularized 4D EGB framework. These findings provide observationally relevant predictions for compact dark-matter objects under modified gravity. |
| title | Anisotropic Dark Matter Bosonic Stars in regularized 4D Einstein$-$Gauss$-$Bonnet gravity |
| topic | General Relativity and Quantum Cosmology High Energy Astrophysical Phenomena High Energy Physics - Theory |
| url | https://arxiv.org/abs/2510.15549 |