Related papers: Semiclassical cosmic string evaporation
We find a self-consistent pp-gravitational shock wave solution to the semiclassical Einstein equations resulting from the $1/N$ approach to the effective action. We model the renormalized matter stress-energy-momentum tensor by $N$ massless…
As a most promising candidate for quantum theory of the gravity, the superstring theory has attracted many researchers including cosmologists. It is expected that the cosmological initial singularity is avoided within the context of the…
The semi-classical cross-sections for arbitrary partial waves of ordinary scalars to fall into certain five-dimensional black holes have a form that seems capable of explanation in terms of the effective string model. The kinematics of…
We study black hole formation and evaporation in a four-dimensional semiclassical model that preserves diffeomorphism invariance and reproduces the one-loop trace anomaly. Solving the quantum-corrected Einstein equations for the collapse of…
On the basis of recently discovered connections between D-branes and black holes, I show how the information puzzle is solved by superstring theory as the fundamental theory of quantum gravity. The picture that emerges is that a…
We consider new cosmological solutions with a collapsing, an intermediate and an expanding phase. The boundary between the expanding (collapsing) phase and the intermediate phase is seen by comoving observers as a cosmological past (future)…
We calculate the gravitational radiation emitted by an infinite cosmic string with two oppositely moving wave-trains, in the small amplitude approximation. After comparing our result to the previously studied cases we extend the results to…
We argue that the paradoxes associated with infinitely degenerate states, which plague relic particle scenarios for the endpoint of black hole evaporation, may be absent when the relics are horned particles. Most of our arguments are based…
We compute the quantum string entropy S_s(m,j) of the microscopic string states of mass m and spin j in two physically relevant backgrounds: Kerr (rotating) black holes and de Sitter (dS) space-time. We find a new formula for the quantum…
This paper deals with the geometry of supermassive cosmic strings. We have used an approach that enforces the spacetime of cosmic strings to also satisfy the conservation laws of a cylindric gravitational topological defect, that is a…
We construct cosmological spacetimes with null Kasner-like singularities as purely gravitational solutions with no other background fields turned on. These can be recast as anisotropic plane-wave spacetimes by coordinate transformations. We…
The observable parameters of the electron indicate unambiguously that its gravitational background should be the Kerr-Newman solution without horizons. This background is not flat and has a non-trivial topology created by the Kerr singular…
Although there is general agreement that a removal of classical gravitational singularities is not only a crucial conceptual test of any approach to quantum gravity but also a prerequisite for any fundamental theory, the precise criteria…
We study a semilinear equation with derivatives satisfying a null condition on slowly rotating Kerr spacetimes. We prove that given sufficiently small initial data, the solution exists globally in time and decays with a quantitative rate to…
In this paper we show how quantum corrections, although perturbatively small, may play an important role in the analysis of the existence of some classical models. This, in fact, appears to be the case of static, uniform--density models of…
We analyze quantum-mechanical counterpart of Newtonian cosmology and show that effects of zero-point motion eliminate classical density singularity. Quantum effects are particularly significant for closed Universes where without the…
The possibility of the cosmic string creation by the vacuum fluctuations of quantum fields in the self-consistent semiclassical theory of gravity is discussed. We use the approximate method for obtaining vacuum expectation value of the…
We discuss data analysis techniques that can be used in the search for gravitational wave bursts from cosmic strings. When data from multiple interferometers are available, we describe consistency checks that can be used to greatly reduce…
Recently, string theory has provided some remarkable new insights into the microphysics of black holes. I argue that a simple and important lesson is also provided with regards to the information loss paradox, namely, pure quantum states do…
If an evaporating black hole does not settle down to a non radiating remnant, a description by a semi classical Lorentz metric must contain either a naked singularity or what we call a thunderbolt, a singularity that spreads out to infinity…