Could a thin-shell configuration lie hidden within the Universe?

Fuente: arXiv
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Autori principali: Cataldo, Mauricio, Cid, Antonella, Labraña, Pedro
Natura: Preprint
Pubblicazione: 2025
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author Cataldo, Mauricio
Cid, Antonella
Labraña, Pedro
author_facet Cataldo, Mauricio
Cid, Antonella
Labraña, Pedro
contents This article explores the cosmological scenario in which our Universe contains a hidden thin-shell configuration. We investigate a degenerate modification of the Friedmann-Robertson-Walker metric obtained through a coordinate transformation applied to the radial coordinate, analogous to recent approaches that address the Big Bang singularity via spacetime defects. The resulting metric, while formally satisfying the standard homogeneous Friedmann equations, actually describes an evolving wormhole geometry with two asymptotically flat Friedmann-Robertson-Walker regions connected by a throat located at the coordinate singularity. Using Israel's junction formalism, we demonstrate that this coordinate singularity corresponds to a thin shell characterized by exotic matter with well-defined surface energy density and isotropic pressure. The shell obeys the barotropic equation of state $p = -ρ/2$, confirming the presence of exotic matter that violates the standard energy condition, which is a requirement for maintaining wormhole geometries. As the universe expands, this thin shell becomes increasingly diluted, scaling as $1/a(t)$ with the cosmic scale factor.
format Preprint
id arxiv_https___arxiv_org_abs_2512_13575
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Could a thin-shell configuration lie hidden within the Universe?
Cataldo, Mauricio
Cid, Antonella
Labraña, Pedro
General Relativity and Quantum Cosmology
This article explores the cosmological scenario in which our Universe contains a hidden thin-shell configuration. We investigate a degenerate modification of the Friedmann-Robertson-Walker metric obtained through a coordinate transformation applied to the radial coordinate, analogous to recent approaches that address the Big Bang singularity via spacetime defects. The resulting metric, while formally satisfying the standard homogeneous Friedmann equations, actually describes an evolving wormhole geometry with two asymptotically flat Friedmann-Robertson-Walker regions connected by a throat located at the coordinate singularity. Using Israel's junction formalism, we demonstrate that this coordinate singularity corresponds to a thin shell characterized by exotic matter with well-defined surface energy density and isotropic pressure. The shell obeys the barotropic equation of state $p = -ρ/2$, confirming the presence of exotic matter that violates the standard energy condition, which is a requirement for maintaining wormhole geometries. As the universe expands, this thin shell becomes increasingly diluted, scaling as $1/a(t)$ with the cosmic scale factor.
title Could a thin-shell configuration lie hidden within the Universe?
topic General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2512.13575