English
Related papers

Related papers: Composite vacuum Brans-Dicke wormholes

200 papers

We investigate a new type of Schwarzschild wormhole, which relies on a 3-dimensional spacetime defect with degenerate metrics. This particular wormhole is a solution of the vacuum Einstein equations. We also study the generalized…

General Relativity and Quantum Cosmology · Physics 2023-07-11 Zi-Liang Wang

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,…

General Relativity and Quantum Cosmology · Physics 2024-12-13 Nailya Ganiyeva

First, the ideas introduced in the wormhole research field since the work of Morris and Thorne are briefly reviewed, namely, the issues of energy conditions, wormhole construction, stability, time machines and astrophysical signatures.…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Jose' P. S. Lemos , Francisco S. N. Lobo , Sergio Quinet de Oliveira

A multidimensional cosmological model with space-time consisting of $n (n \ge 2)$ Einstein spaces $M_{i}$ is investigated in the presence of a cosmological constant $\Lambda$ and a homogeneous minimally coupled scalar field $\varphi(t)$ as…

General Relativity and Quantum Cosmology · Physics 2009-10-22 U. Bleyer , V. D. Ivashchuk , V. N. Melnikov , A. Zhuk

In this paper I present a new class of traversable wormholes. This is done by surgically grafting two Schwarzschild spacetimes together in such a way that no event horizon is permitted to form. This surgery concentrates a non--zero…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Matt Visser

The purpose of this study is to investigate observational features of Brans-Dicke wormholes in a case if they exist in our Universe. The energy flux from accretion onto a Brans-Dicke wormhole and the so-called "maximum impact parameter" are…

General Relativity and Quantum Cosmology · Physics 2015-05-27 Stanislav Alexeyev , Kristina Rannu , Dilia Gareeva

In this paper, we explore static spherically symmetric wormhole solutions in the framework of $n$-dimensional Einstein Gauss-Bonnet gravity. Our objective is to find out wormhole solutions that satisfy energy conditions. For this purpose,…

General Physics · Physics 2016-11-02 Shamaila Rani , Abdul Jawad

The well-known problem of wormholes in general relativity (GR) is the necessity of exotic matter, violating the Weak Energy Condition (WEC), for their support. This problem looks easier if, instead of island-like configurations, one…

General Relativity and Quantum Cosmology · Physics 2020-01-08 K. A. Bronnikov , S. V. Bolokhov , M. V. Skvortsova

A simple Heckmann's vacuum wormhole solution of Jordan-Brans-Dicke gravitation is presented and analysed. It is shown that in contrast with class I Brans solution where the throat radius becomes real when $\omega < -4/3$ here it becomes…

General Relativity and Quantum Cosmology · Physics 2015-03-17 S. M. Kozyrev

Exact solutions of traversable wormholes are found under the assumption of spherical symmetry and the existence of a {\it non-static} conformal symmetry, which presents a more systematic approach in searching for exact wormhole solutions.…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Christian G. Boehmer , Tiberiu Harko , Francisco S. N. Lobo

In 1921 Bach and Weyl derived the method of superposition to construct new axially symmetric vacuum solutions of General Relativity. In this paper we extend the Bach-Weyl approach to non-vacuum configurations with massless scalar fields.…

General Relativity and Quantum Cosmology · Physics 2016-08-17 A. I. Egorov , P. E. Kashargin , Sergey V. Sushkov

In this paper, we explore higher-dimensional asymptotically flat wormhole geometries in the framework of Gauss-Bonnet (GB) gravity and investigate the effects of the GB term, by considering a specific radial-dependent redshift function and…

General Relativity and Quantum Cosmology · Physics 2015-04-06 Mohammad Reza Mehdizadeh , Mahdi Kord Zangeneh , Francisco S. N. Lobo

In this paper, we construct generic, spherically symmetric thin-shell wormholes and check their stabilities using the unified dark sector, including dark energy and dark matter. We give a master equation, from which one can recover, as a…

General Relativity and Quantum Cosmology · Physics 2017-12-22 Ali Övgün , Kimet Jusufi

Wormholes are non-trivial topological structures that arise as exact solutions to Einstein's field equations, theoretically connecting distinct regions of spacetime via a throat-like geometry. While static traversable wormholes necessarily…

General Relativity and Quantum Cosmology · Physics 2025-07-22 Mahdi Kord Zangeneh , Francisco S. N. Lobo

The Brans Class I solution in Brans-Dicke gravity is a staple in the study of gravitational theories beyond General Relativity. Discovered in 1961, it describes the exterior vacuum of a spherical Brans-Dicke star and is characterized by two…

General Relativity and Quantum Cosmology · Physics 2024-07-26 Hoang Ky Nguyen , Bertrand Chauvineau

New, simple models of ``black hole interiors'', namely spherically symmetric solutions of the Einstein field equations in matter matching the Schwarzschild vacuum at spacelike hypersurfaces ``R<2M'' are constructed. The models satisfy the…

General Relativity and Quantum Cosmology · Physics 2010-11-19 Giulio Magli

Spherically symmetric thin-shell wormholes in the presence of a cosmological constant are constructed applying the cut-and-paste technique implemented by Visser. Using the Darmois-Israel formalism the surface stresses, which are…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Francisco S. N. Lobo , Paulo Crawford

In this work, we derive an exact vacuum solution to the Einstein field equations that depends on three constant parameters: the throat radius $r_0$, a parameter $q$, which is closely associated with the Komar mass, and a parameter $s$,…

General Relativity and Quantum Cosmology · Physics 2026-02-24 I. A. Sarmiento-Alvarado , Leonel Bixano , Tonatiuh Matos

The newly discovered Wormhole C--metric is a solution of Einstein's field equation coupled with a phantom scalar field which describes the accelerated wormholes. In the zero acceleration limit the solution reduces to an asymptotically flat…

General Relativity and Quantum Cosmology · Physics 2024-07-12 Soham Chatterjee , Sagnik Roy , Ratna Koley

Wormholes and black holes have traditionally been treated a quite separate objects with relatively little overlap. The possibility of a connection arises in that wormholes, if they exist, might have profound influence on black holes, their…

General Relativity and Quantum Cosmology · Physics 2013-08-27 Matt Visser , David Hochberg