Related papers: The circular loop equation of a cosmic string with…
The tensionless limit of the free bosonic string is space-time conformally symmetric classically. Requiring invariance of the quantum theory in the light cone gauge tests the reparametrization symmetry needed to fix this gauge. The full…
Gravitational field of a stationary circular cosmic string loop has been studied in the context of full nonlinear Einstein's theory of gravity. It has been assumed that the radial and tangential stresses of the loop are equal to the energy…
Aspects of string cosmology for critical and non-critical strings are discussed emphasizing the necessity to account for the dilaton dynamics for a proper incorporation of ``large - small" duality. This drastically modifies the intuition…
A network of cosmic strings would lead to gravitational waves which may be detected by pulsar timing or future interferometers. The details of the gravitational wave signal depend on the distribution of cosmic string loops, which are…
The problem of dark energy arises due to its self-gravitating properties. Therefore explaining vacuum energy may become a question for the realm of quantum gravity, that can be addressed within string theory context. In this talk I…
We consider a quantum field theory on a spherically symmetric quantum space time described by loop quantum gravity. The spin network description of space time in such a theory leads to equations for the quantum field that are discrete. We…
We study the gravi-dilaton field of a Schwarzschild black hole pierced by a thin cosmic string in both massless and massive dilatonic gravity. We conclude that in the thin vortex approximation the string's spacetime is asymptotically flat…
We study the behaviour and consequences of cosmic string networks in contracting universes. They approximately behave during the collapse phase as a radiation fluids. Scaling solutions describing this are derived and tested against…
We construct a time-dependent solution in vacuum string field theory and investigate whether the solution can be regarded as a rolling tachyon solution. First, compactifying one space direction on a circle of radius R, we construct a…
An axisymmetric collapse of non-rotating gravitational waves is numerically investigated in the subcritical regime where no black holes form but where curvature attains a maximum and decreases, following the dispersion of the initial wave…
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…
Black hole spacetimes are semiclassically not static. For black holes whose lifetime is larger than the age of the universe we compute, in leading order, the power spectrum of deviations of the electromagnetic charge from it's average…
Motivated by high interest in the close relation between string theory and black hole solutions, in this paper, we take into account the Einstein-Gauss-Bonnet Lagrangian in the context of massive gravity. We examine the possibility of black…
A general formulation for describing odd-harmonic cosmic strings is developed and used to determine the self-intersection properties of high-harmonic loops. This is important because loop formation mechanisms produce high-harmonic…
A charged, non-rotating, spherically symmetric black hole which has cosmological constant $\Lambda$ (Reissner-Nordstr\"om+$\Lambda$ or RN+$\Lambda$), active gravitational mass $M$ and electric charge $Q$ is studied with exterior…
Cosmic strings can be created in the early universe during symmetry-breaking phase transitions, such as might arise if the gauge structure of the standard model is extended by additional U(1) factors at high energies. Cosmic strings present…
We solve numerically the Boltzmann equation describing the evolution of a cosmic string network which contains only loops. In Minkowski space time the equilibrium solution predicted by statistical mechanics is recovered, and we prove that…
Dynamical black-hole scenarios have been developed in loop quantum gravity in various ways, combining results from mini and midisuperspace models. In the past, the underlying geometry of space-time has often been expressed in terms of line…
The dynamical evolution of superconducting cosmic strings is much more complicated than that of simple Goto-Nambu strings. For this reason, there are only a few known analytical solutions and no numerical ones. The goal of this paper is to…
The behaviour of a relativistic scalar particle subject to a scalar potential under the effects of the violation of the Lorentz symmetry in the cosmic string spacetime is discussed. It is considered two possible scenarios of the Lorentz…