Related papers: Could a thin-shell configuration lie hidden within…
The thin-shell wormhole created using the Darmois-Israel formalism applied to Robinson-Trautman family of spacetimes is presented. The stress energy tensor created on the throat is interpreted in terms of two dust streams and it is shown…
We discuss theories in which the standard-model particles are localized on a brane embedded in space-time with large compact extra dimensions, whereas gravity propagates in the bulk. In addition to the ground state corresponding to a…
In the presence of a minimal length physical objects cannot collapse to an infinite density, singular, matter point. In this note we consider the possible final stage of the gravitational collapse of "thick" matter layers. The energy…
We describe an accelerating universe model in the context of a scalar-tensor theory. This model is intrinsically closed, and is filled with quintessence-like scalar field components, in addition to the Cold Dark Matter component. With a…
We created a model of several dimensional physical universe. The extra dimensions associated with the four dimensional physical universe is assumed to have modified Gidding-Strominger wormhole core. This core is separated by a flexible…
An approach to cosmological modelling is presented that incorporates the inhomogeneous structure of the Cosmic Web, specifically focusing on the interplay between cosmic voids and density walls. We extend the standard homogeneous and…
We study the stability of different higher dimensional thin--shell wormholes (HDTSW) in general relativity with a cosmological constant. We show that a $d$--dimensional thin--shell wormhole surrounded by quintessence can have three…
The quantum black hole model with a self-gravitating spherically symmetric thin dust shell as a source is considered. The shell Hamiltonian constraint is written and the corresponding Schroedinger equation is obtained. This equation…
First a Friedmann-Robertson-Walker (FRW) universe filled with dust and a conformally invariant scalar field is quantized. For the closed model we find a discrete set of wormhole quantum states. In the case of flat spacelike sections we find…
We study gravitationally bound, spherically symmetric equilibrium configurations consisting of ordinary (neutron-star) matter and of a phantom/ghost scalar field which provides the nontrivial topology in the system. For such mixed…
In continuation of a preceding work on introducing asymmetric thin-shell wormholes as an emerging class of traversable wormholes within the context, this time cylindrically symmetric spacetimes are exploited to construct such wormholes.…
A possible candidate for the present accelerated expansion of the Universe is ''phantom energy'', which possesses an equation of state of the form $\omega\equiv p/\rho<-1$, consequently violating the null energy condition. As this is the…
Recent observations indicate that the Universe is not transparent but partially opaque due to absorption of light by ambient cosmic dust. This implies that the Friedmann equations valid for the transparent universe must be modified for the…
We propose a construction with which to resolve the black hole singularity and enable an anisotropic cosmology to emerge from the inside of the hole. The model relies on the addition of an S-brane to the effective action which describes the…
In this study, we explore a topologically charged higher-dimensional traversable defect wormhole, with a specific emphasis on five dimensions. Particularly noteworthy is the fact that the matter-energy distribution attributed to this…
In this review we focus our attention on scalar-tensor gravity models and their empirical verification in terms of black hole and wormhole physics. We focus on a black hole, embedded in an expanding universe, describing both cosmological…
We consider a variant of the brane-world model in which the universe is the direct product of a Friedmann, Robertson-Walker (FRW) space and a compact hyperbolic manifold of dimension $d\geq2$. Cosmology in this space is particularly…
Spacetime singularities have been discovered which are physically much weaker than those predicted by the classical singularity theorems. Geodesics evolve through them and they only display infinities in the derivatives of their curvature…
The various "defect wormholes" developed by Klinkhamer have recently attracted considerable attention -- especially in view of the fact that the simplest example, the so-called "vacuum defect wormhole", was claimed to be an…
The cosmological principle, promoting the view that the universe is homogeneous and isotropic, is embodied within the mathematical structure of the Robertson-Walker (RW) metric. The equations derived from an application of this metric to…