Wormhole geometries in modified gravity

Fuente: arXiv
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Autor principal: Ganiyeva, Nailya
Formato: Preprint
Publicado: 2024
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author Ganiyeva, Nailya
author_facet Ganiyeva, Nailya
contents In this thesis, we investigate traversable wormhole spacetimes within the context of a covariant generalization of Einstein's General Relativity, namely the energy-momentum squared gravity, denoted as $f\left(R,T_{ab}T^{ab}\right)$. Here, $R$ represents the Ricci scalar and $T_{ab}$ is the energy-momentum tensor. Specifically considering the linear form $f\left(R,T_{ab}T^{ab}\right)=R+γT_{ab}T^{ab}$, we demonstrate the existence of numerous wormhole solutions, wherein the matter fields satisfy all energy conditions, these being the null, weak, strong, and dominant energy conditions. Remarkably, these solutions do not require fine-tuning of the free parameters inherent to the model. Given the complicated nature of the field equations, we develop an analytical recursive algorithm to derive these solutions. One limitation is that these solutions lack natural localization, necessitating then a matching with an external vacuum spacetime. To address this, we derive the junction conditions for the theory, establishing that any matching between two spacetimes must be smooth, i.e. without the presence of thin-shells at the boundary. Ultimately, applying these junction conditions allows us to match the interior wormhole spacetime with an exterior vacuum described by the Schwarzschild solution. Therefore, we obtain traversable, localized, static, and spherically symmetric wormhole solutions that satisfy all energy conditions across the entire spacetime range. Additionally, we demonstrate that the approach used in this study can be easily generalized to more complicated dependencies of the action on $T_{ab}T^{ab}$, provided there are no crossed terms between $R$ and $T_{ab}T^{ab}$.
format Preprint
id arxiv_https___arxiv_org_abs_2412_09228
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Wormhole geometries in modified gravity
Ganiyeva, Nailya
General Relativity and Quantum Cosmology
In this thesis, we investigate traversable wormhole spacetimes within the context of a covariant generalization of Einstein's General Relativity, namely the energy-momentum squared gravity, denoted as $f\left(R,T_{ab}T^{ab}\right)$. Here, $R$ represents the Ricci scalar and $T_{ab}$ is the energy-momentum tensor. Specifically considering the linear form $f\left(R,T_{ab}T^{ab}\right)=R+γT_{ab}T^{ab}$, we demonstrate the existence of numerous wormhole solutions, wherein the matter fields satisfy all energy conditions, these being the null, weak, strong, and dominant energy conditions. Remarkably, these solutions do not require fine-tuning of the free parameters inherent to the model. Given the complicated nature of the field equations, we develop an analytical recursive algorithm to derive these solutions. One limitation is that these solutions lack natural localization, necessitating then a matching with an external vacuum spacetime. To address this, we derive the junction conditions for the theory, establishing that any matching between two spacetimes must be smooth, i.e. without the presence of thin-shells at the boundary. Ultimately, applying these junction conditions allows us to match the interior wormhole spacetime with an exterior vacuum described by the Schwarzschild solution. Therefore, we obtain traversable, localized, static, and spherically symmetric wormhole solutions that satisfy all energy conditions across the entire spacetime range. Additionally, we demonstrate that the approach used in this study can be easily generalized to more complicated dependencies of the action on $T_{ab}T^{ab}$, provided there are no crossed terms between $R$ and $T_{ab}T^{ab}$.
title Wormhole geometries in modified gravity
topic General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2412.09228