Related papers: Gravitational and Particle Radiation from Cosmic S…
The unique, conical spacetime created by cosmic strings brings about distinctive gravitational lensing phenomena. The variety of these distinctive phenomena is increased when the strings have non-trivial mutual interactions. In particular,…
We study the scattering of a massless and neutral test particle in the gravitational field of a body (the string star) made of a large number of scalar states of the superstring. We consider two cases, the one in which these states are…
In the weak field approximation the gravitational wave is approximated as a linear wave, which ignores the nonlinear effect. In this paper, we present an exact general solution of the cylindrical gravitational wave. The exact solution of…
We investigate the line element of spacetime around a linear cosmic string in the presence of a cosmological constant. We obtain the metric and argue that it should be discarded because of asymptotic considerations. Then a time dependent…
We study numerically the gravitational field of a star made of massive and neutral string states for the case in which the dilaton is massive. The solution exhibits very simple scaling properties in the dilaton mass. There is no horizon and…
The metric around a wiggly cosmic string is calculated in the linear approximation of Brans-Dicke theory of gravitation. The equations of motion for relativistic and non-relativistic particles in this metric are obtained. Light propagation…
We study the behaviour of a non-relativistic quantum particle interacting with different potentials, in the background spacetime generated by a cosmic string. We find the energy spectra for the quantum systems under consideration and…
This paper discusses the gravitational scattering of a straight, infinitely long test cosmic string by a black hole. We present numerical results that probe the two-dimensional parameter space of impact parameter and initial velocity and…
Gravitational waves from cosmic strings are generated in the first fractions of a second after the Big Bang, potentially providing a unprecedented probe of the early universe. We discuss the key dynamical processes underlying calculations…
We report that axions and photons exhibit instability in the presence of cosmic strings that are carrying magnetic flux in their core. The strength of the instability is determined by the symmetry breaking scale of the cosmic string theory.…
The time-dependent metric of a cosmic string leads to an effective interaction between the string and photons - the "gravitational Aharonov-Bohm" effect -- and causes cosmic strings to emit light. We evaluate the radiation of pairs of…
We consider the gravitationally induced particle production from the quantum vacuum which is defined by a free, massless and minimally coupled scalar field during the formation of a gauge cosmic string. Previous discussions of this topic…
In this article, the behavior of a straight cosmic string is studied for the linearized version of Horndeski theory in cases where the scalar field is massless or massive. Several physical properties of such solutions are discussed in…
I present a class of objects called gravitational strings (GS) for their similarity to the conventional cosmic strings: even though the former are just singularities in flat spacetime, both varieties are equally "realistic", they may play…
We study spatial variations of the fine-structure constant in the presence of static straight cosmic strings in the weak-field approximation in Einstein gravity. We work in the context of a generic Bekenstein-type model and consider a gauge…
The gravitational field of a laser pulse of finite lifetime, is investigated in the framework of linearized gravity. Although the effects are very small, they may be of fundamental physical interest. It is shown that the gravitational field…
The gravitational lensing by long, wiggly cosmic strings is shown to produce a large number of lensed images of a background source. In addition to pairs of images on either side of the string, a number of small images outline the string…
Appearance of cosmic strings in the early Universe is a common manifestation of new physics typically linked to some high energy scale. In this paper, we discuss a different situation, where a model underlying cosmic string formation is…
Linearized gravitational waves in de Sitter space-time are analyzed in detail to obtain guidance for constructing the theory of gravitational radiation in presence of a positive cosmological constant in full, nonlinear general relativity.…
The gravitational properties of cosmic strings in the Randall-Sundrum brane world scenario are investigated. Using a gauge in which the brane remains straight, the leading order corrections to the metric on the brane are determined. In…