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We investigate wormhole solutions using the modified gravity model $f(Q,T)$ with viscosity and aim to find a solution for the existence of wormholes mathematically without violating the energy conditions. We show that there is no need to…

General Relativity and Quantum Cosmology · Physics 2024-10-08 S. Davood Sadatian , S. Mohamad Reza Hosseini

We consider neutron-star-plus-wormhole configurations supported by a massless ghost scalar field. The neutron fluid is modeled by an anisotropic equation of state. When the central energy density of the fluid is of comparable magnitude to…

General Relativity and Quantum Cosmology · Physics 2014-04-15 Vladimir Dzhunushaliev , Vladimir Folomeev , Burkhard Kleihaus , Jutta Kunz

This work is devoted to the study of analytic wormhole solutions within the framework of $f(R)$ gravity theory. To check the possibility of having wormhole structures satisfying energy conditions, by means of the class I approach the pair…

General Relativity and Quantum Cosmology · Physics 2022-06-09 A. S. Agrawal , B. Mishra , Francisco Tello-Ortiz , A. Alvarez

We explore the possibility of dynamic wormhole geometries, within the context of nonlinear electrodynamics. The Einstein field equation imposes a contracting wormhole solution and the obedience of the weak energy condition. Furthermore, in…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Aaron V. B. Arellano , Francisco S. N. Lobo

A class of exact solutions of the Einstein field equations representing non-static wormholes that obey the {\em weak and dominant energy conditions } is presented. Hence, in principle, these wormholes can be built with less exotic matter…

General Relativity and Quantum Cosmology · Physics 2009-07-07 Anzhong Wang , Patricio S. Letelier

Here, we propose a new exponential shape function in wormhole geometry within modified gravity. The energy conditions and equation of state parameter are obtained. The radial and tangential null energy conditions are validated, as well as…

We present new traversable wormhole and non-singular black hole solutions in pure, scale-free $R^2$ gravity. These exotic solutions require no null energy condition violating or "exotic" matter and are supported only by the vacuum of the…

General Relativity and Quantum Cosmology · Physics 2015-09-02 Francis Duplessis , Damien A. Easson

A positive cosmological constant simplifies the asymptotics of forever expanding cosmological solutions of the Einstein equations. In this paper a general mathematical analysis on the level of formal power series is carried out for vacuum…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Alan D. Rendall

We analyze the stress-energy tensor necessary to generate a general stationary and axisymmetric spacetime. The constraints on the geometry arising from considering a perfect fluid as a source are derived. For a fluid with a nonzero stress…

General Relativity and Quantum Cosmology · Physics 2007-05-23 S. E. Perez Bergliaffa , K. E. Hibberd

We derive a shortcut stationary metric formula for generating imperfect fluid rotating solutions, in Boyer-Lindquist coordinates, from spherically symmetric static ones. We explore the properties of the curvature scalar and stress-energy…

General Relativity and Quantum Cosmology · Physics 2014-05-12 Mustapha Azreg-Aïnou

We construct a model of a rotating wormhole made by cutting and pasting two Kerr spacetimes. As a result, we obtain a rotating thin-shell wormhole with exotic matter at the throat. Two candidates for the exotic matter are considered: (i) a…

General Relativity and Quantum Cosmology · Physics 2015-03-18 P. E. Kashargin , S. V. Sushkov

Recently, a modified theory of gravity was presented, which consists of the superposition of the metric Einstein-Hilbert Lagrangian with an $f(\cal R)$ term constructed \`{a} la Palatini. The theory possesses extremely interesting features…

General Relativity and Quantum Cosmology · Physics 2012-12-20 Salvatore Capozziello , Tiberiu Harko , Tomi S. Koivisto , Francisco S. N. Lobo , Gonzalo J. Olmo

We construct and analyse wormhole solutions in quantised space-time. The field equations are constructed from the deformed wormhole metric in the proper reference frame using tetrads. The spatial geometry of the wormhole is analysed in the…

General Relativity and Quantum Cosmology · Physics 2025-01-28 Harsha Sreekumar , E. Harikumar

This paper addresses the following issues: (1) the possible existence of macroscopic traversable wormholes, given a noncommutative-geometry background, and (2) the possibility of allowing zero tidal forces, given a known density. It is…

General Relativity and Quantum Cosmology · Physics 2019-01-09 Peter K. F. Kuhfittig

In this work, we undertake an analysis of new wormhole solutions within an action-dependent Lagrangian framework. These geometries can be traversable and supported by a positive energy density. The modification of the gravitational field…

General Relativity and Quantum Cosmology · Physics 2024-06-12 Ismael Ayuso , Ruth Lazkoz

We classify wormholes endowed with redshift effects and finite mass into three types. Type I wormholes have their radial pressure dying out faster, as one moves away from the throat, than any other component of the stress-energy and thus…

General Relativity and Quantum Cosmology · Physics 2015-07-27 Mustapha Azreg-Aïnou

Lack of a consistent metric for generating rotating wormholes motivates us to present a new one endowed with interesting physical and geometrical properties. When combined with the generalized method of superposition of fields, which…

General Relativity and Quantum Cosmology · Physics 2016-01-07 Mustapha Azreg-Aïnou

In this paper, we consider third order Lovelock gravity with a cosmological constant term in an n-dimensional spacetime $\mathcal{M}^{4}\times \mathcal{K}^{n-4}$, where $\mathcal{K}^{n-4} $ is a constant curvature space. We decompose the…

General Relativity and Quantum Cosmology · Physics 2015-12-23 Mahdi Kord Zangeneh , Francisco S. N. Lobo , Mohammad Hossein Dehghani

Traversable wormhole are primarily useful as "gedanken-experiments" and as a theoretician's probe of the foundations of general relativity. In this work, we analyse the possibility of having tunnels in a hyperbolic spacetime. We obtain…

General Relativity and Quantum Cosmology · Physics 2010-09-02 Francisco S. N. Lobo , José P. Mimoso

In this work, we explore the possibility that static and spherically symmetric traversable wormhole geometries are supported by modified teleparallel gravity or f(T) gravity, where T is the torsion scalar. Considering the field equations…

General Relativity and Quantum Cosmology · Physics 2012-02-16 Christian G. Boehmer , Tiberiu Harko , Francisco S. N. Lobo