We present a new family of exact four-dimensional Taub-NUT spacetimes in Einstein-Λ theory supplemented with a conformally coupled scalar field exhibiting a power-counting superrenormalizable potential. Our configurations are constructed in the following manner: A solution of a conformally coupled theory with a conformal potential, henceforth the seed (gμν,ϕ), is transformed by the action of a specific change of frame in addition with a simultaneous shift of the seed scalar field. The conformal factor of the transformation and the shift are both affine functions of the original scalar ϕ. The new configuration, (g¯μν,ϕ¯), solves the field equations of a conformally coupled theory with the extended aforementioned superrenormalizable potential, this under the presence of an effective cosmological constant. The new spectrum of solutions is notoriously enhanced with respect to the original seed containing regular black holes, wormholes, and bouncing cosmologies. We highlight the existence of two types of exact black bounces given by de Sitter and anti–de Sitter geometries that transit across three different configurations each. The de Sitter geometries transit from a regular black hole with event and cosmological horizons to a bouncing cosmology that connects two de Sitter Universes with different values of the asymptotic cosmological constant. An intermediate phase, which might be represented by two different configurations, takes place. These configurations are given by a de Sitter wormhole or by a bouncing cosmology that connects two de Sitter Universes, both under the presence of a cosmological horizon. On the other hand, the anti–de Sitter geometries transit from a regular black hole with inner and event horizons to a wormhole that connects two asymptotic boundaries with different constant curvatures. The intermediate phase is given in this case by an anti–de Sitter regular black hole with a single event horizon. This regular black hole might appear in two different configurations. As a regular anti–de Sitter black hole inside of an anti-de Sitter wormhole or as an anti–de Sitter regular black hole with a cosmological bounce in its interior. All these geometries are shown to be smoothly connected by the mass parameter only. Other standard stationary black holes, bouncing cosmologies and wormholes are also identified.

AdS-Taub-NUT spacetimes and exact black bounces with scalar hair / B. Josè, C. Adolfo, M. Nicolàs, A. Vigano'. - In: PHYSICAL REVIEW D. - ISSN 2470-0010. - 106:2(2022 Jul 20), pp. 024038.024038-1-024038.024038-25. [10.1103/physrevd.106.024038]

AdS-Taub-NUT spacetimes and exact black bounces with scalar hair

A. Vigano'
2022

Abstract

We present a new family of exact four-dimensional Taub-NUT spacetimes in Einstein-Λ theory supplemented with a conformally coupled scalar field exhibiting a power-counting superrenormalizable potential. Our configurations are constructed in the following manner: A solution of a conformally coupled theory with a conformal potential, henceforth the seed (gμν,ϕ), is transformed by the action of a specific change of frame in addition with a simultaneous shift of the seed scalar field. The conformal factor of the transformation and the shift are both affine functions of the original scalar ϕ. The new configuration, (g¯μν,ϕ¯), solves the field equations of a conformally coupled theory with the extended aforementioned superrenormalizable potential, this under the presence of an effective cosmological constant. The new spectrum of solutions is notoriously enhanced with respect to the original seed containing regular black holes, wormholes, and bouncing cosmologies. We highlight the existence of two types of exact black bounces given by de Sitter and anti–de Sitter geometries that transit across three different configurations each. The de Sitter geometries transit from a regular black hole with event and cosmological horizons to a bouncing cosmology that connects two de Sitter Universes with different values of the asymptotic cosmological constant. An intermediate phase, which might be represented by two different configurations, takes place. These configurations are given by a de Sitter wormhole or by a bouncing cosmology that connects two de Sitter Universes, both under the presence of a cosmological horizon. On the other hand, the anti–de Sitter geometries transit from a regular black hole with inner and event horizons to a wormhole that connects two asymptotic boundaries with different constant curvatures. The intermediate phase is given in this case by an anti–de Sitter regular black hole with a single event horizon. This regular black hole might appear in two different configurations. As a regular anti–de Sitter black hole inside of an anti-de Sitter wormhole or as an anti–de Sitter regular black hole with a cosmological bounce in its interior. All these geometries are shown to be smoothly connected by the mass parameter only. Other standard stationary black holes, bouncing cosmologies and wormholes are also identified.
Settore FIS/02 - Fisica Teorica, Modelli e Metodi Matematici
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/944289
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