Related papers: Wormholes or Gravastars?
In this work, we consider a Yukawa modification of the Casimir wormhole. With the help of an Equation of State, we impose Zero Tidal Forces. We will examine two different approaches: in a first approach, we will fix the form of the shape…
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…
It has been argued that wormholes are as good a prediction of Einstein's theory as black holes but the theoretical construction requires a reverse strategy, specifying the desired geometric properties of the wormhole and leaving open the…
Analytic solutions are presented which describe the construction of a traversable wormhole from a Schwarzschild black hole, and the enlargement of such a wormhole, in Einstein gravity. The matter model is pure radiation which may have…
We apply duality rotations and complex transformations to the Schwarzschild metric to obtain wormhole geometries with two asymptotically flat regions connected by a throat. In the simplest case these are the well-known wormholes supported…
Recently it has been argued that the phantom thin-shell wormholes matched with the Schwarzschild space-time near the Schwarzschild radius ring like Schwarzschild black holes at early times, but differently at late times (arXiv:1602.07309).…
Zeta function regularization is an effective method to extract physical significant quantities from infinite ones. It is regarded as mathematically simple and elegant but the isolation of the physical divergency is hidden in its analytic…
Mazur and Mottola's gravastar model represents one of the few serious alternatives to the traditional understanding of the black hole. The gravastar is typically regarded as a theoretical alternative for the black hole. This article…
We obtain an hybrid expression for the heat-kernel, and from that the density of the free energy, for a minimally coupled scalar field in a Schwarzschild geometry at finite temperature. This gives us the zero-point energy density as a…
We derive the equations of motion of a test particle in the equatorial plane around a static and spherically symmetric wormhole influenced by a radiation field including the general relativistic Poynting-Robertson effect. From the analysis…
Astrophysical black holes arise as exact solutions of the Einstein field equations. Therefore, any alternative, such as a gravastar, must satisfy the same level of mathematical rigor and internal consistency. A physically viable gravastar…
Utilizing the Hamiltonian constraints approach, a quantum-corrected solution has been derived \cite{Zhang:2024ney}, which describes either a regular black hole or a traversable wormhole, contingent upon the value of the quantum parameter.…
In the Wheeler-DeWitt framework, by a gauge fixing procedure, we set up a scheme to recover a Schr\"odinger type equation, living in the orbits space with the {\it lapse} function as evolution parameter. By means of the associated…
A new model of gravastar is obtained in $D$-dimensional Einstein gravity. This class of solutions includes the gravastar as an alternative to D-dimensional versions of the Schwarzschild-Tangherlini black hole. The configuration of this new…
Noncommutative geometry, an offshoot of string theory, replaces point-like objects by smeared objects. The resulting uncertainty may cause a black hole to be observationally indistinguishable from a traversable wormhole, while the latter,…
We discuss massive scalar perturbations of a Schwarzschild black hole. We argue that quantum effects alter the effective potential near the horizon resulting in Poincare recurrences in Green functions. Results at the semi-classical level…
In this work, a generalization of the Mazur-Mottola gravastar model is explored, by considering a matching of an interior solution governed by the dark energy equation of state, $\omega\equiv p/ \rho<-1/3$, to an exterior Schwarzschild…
This paper discusses the possible existence of traversable wormholes in f(R) modified gravity while assuming a noncommutative-geometry background, as well as zero tidal forces. The first part of the paper aims for an overview via several…
We calculate the gravitational energy spectrum of the perturbations of a Schwarzschild black hole described by quasinormal modes, in the framework of the teleparallel equivalent of general relativity (TEGR). We obtain a general formula for…
It is well known that traversable wormholes are valid solutions of the Einstein field equations, but these structures can only be maintained by violating the null energy condition. In this paper, we have obtained such wormhole solutions in…