Related papers: Large photon productions in a gravitational collap…
The gravitational back-reaction is calculated for the conformally invariant scalar field within a black cosmic string interior with cosmological constant. Using the perturbed metric, the gravitational effects of the quantum field are…
Dynamical wave function collapse models entail the continuous liberation of a specified rate of energy arising from the interaction of a fluctuating scalar field with the matter wave function. We consider the wave function collapse process…
We explore the possibility of gravitationally generated particle production in the scalar-tensor representation of $f(R,T)$ gravity. Due to the explicit nonminimal curvature-matter coupling in the theory, the divergence of the matter…
We investigate the gravitational collapse of a spherically symmetric, inhomogeneous star, which is described by a perfect fluid with heat flow and satisfies the equation of state $p=\rho/3$ at its center. In the process of the gravitational…
We review our recent theoretical results about inequivalence between passive and active gravitational masses and energy in semiclassical variant of general relativity, where gravitational field is not quantized but matter is quantized. To…
In the framework of an effective field theory of general relativity a model of scalar and vector bosons interacting with the metric field is considered. It is shown in the framework of a two-loop order calculation that for the cosmological…
It is well known that the cosmological constant term in the Einstein field equations can be interpreted as a stress tensor for dark energy. This stress tensor is formally analogous to an elastic constitutive equation in continuum mechanics.…
In the present thesis, the author reviews the physics of cosmological first-order phase transitions that may have occured shortly after the Big Bang. Such transitions proceed via the nucleation and expansion of true vacuum bubbles and give…
A kinetic theory of vacuum particle creation under the action of an inertial mechanism is constructed within a nonpertrubative dynamical approach. At the semi-phenomenological level, the inertial mechanism corresponds to quantum field…
Based on the analogy with superconductor physics we consider a scalar-vector-tensor gravitational model, in which the dark energy action is described by a gauge invariant electromagnetic type functional. By assuming that the ground state of…
An intriguing consequence of quantum field theory is that vacuum is not empty space; it is full of quantum fluctuating electromagnetic fields, or virtual photons, corresponding to their zero-point energy, even though the average number of…
In a recent paper (Phys. Rev. D95, 103504 (2017)) it is argued that, due to the fluctuations around its mean value, vacuum energy gravitates differently from what previously assumed. As a consequence, the universe would accelerate with a…
In the framework of the theory of scale relativity, we suggest a solution to the cosmological problem of the formation and evolution of gravitational structures on many scales. This approach is based on the giving up of the hypothesis of…
In this paper, we explore a collapsing scenario in the background of energy-momentum squared gravity (EMSG). EMSG claims to have terms that originate from the quantum gravity effects mimicking loop quantum gravity. As a result, the…
We present an approach to the problem of vacuum energy in cosmology, based on dynamical screening of Lambda on the horizon scale. We review first the physical basis of vacuum energy as a phenomenon connected with macroscopic boundary…
We compute the production of particles from the gravitational field of an expanding mass shell. Contrary to the situation of Hawking radiation and the production of cosmological perturbations during cosmological inflation, the example of an…
It is shown that so-called dark energy could possible be a manifestation of the gravitational vortex producing the "gravitomagnetic" (GM) force field: associated with cosmic matter rotation and inertial spacetime frame dragging. The general…
We study the quantum particle creation in a toy model of spherically symmetric gravitational collapse whose final product is not a black hole but a gravastar. Precedent studies revealed that even in the case of the gravitational collapse to…
A rather minimal possibility is that dark matter consists of the gauge bosons of a spontaneously broken symmetry. Here we explore the possibility of detecting the gravitational waves produced by the phase transition associated with such…
Astronomical observations indicate an accelerated cosmic expansion, the cause of which is explained by the action of `dark energy'. Here we show that in discrete expanding space-time, only a tiny fraction of the vacuum fluctuations can…