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The possibility that the strength of gravitational interactions might slowly increase with distance, is explored by formulating a set of effective field equations, which incorporate the gravitational, vacuum-polarization induced, running of…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Herbert W. Hamber , Ruth M. Williams

We consider gravitational waves from a pair of monopoles or black holes that are moving non-relativistically and are connected by a cosmic string. Shortly after the binary's formation, the connecting string straightens due the direct…

General Relativity and Quantum Cosmology · Physics 2024-07-30 Ahmed Sheta , Yuri Levin

The formalism for computing the gravitational power radiation from excitations on cosmic strings forming a junction is presented and applied to the simple case of co-planar strings at a junction when the excitations are generated along one…

High Energy Physics - Theory · Physics 2009-02-12 Robert Brandenberger , Hassan Firouzjahi , Johanna Karouby , Shahram Khosravi

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…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Xavier Siemens , Ken D. Olum

If the gravitational interaction is unified with the electroweak and strong interactions at a mass M=10^15 GeV, the evolution of Newton's constant must differ from its classical (general relativistic) form. We can model such behavior by…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. C. Melissinos

An implicit, fully characteristic, numerical scheme for solving the field equations of a cosmic string coupled to gravity is described. The inclusion of null infinity as part of the numerical grid allows us to apply suitable boundary…

General Relativity and Quantum Cosmology · Physics 2009-10-31 U. Sperhake , K. R. P. Sjodin , J. A. Vickers

The cosmological constant problem is usually considered an inevitable feature of any effective theory capturing well-tested gravitational and matter physics, without regard to the details of short-distance gravitational couplings. In this…

High Energy Physics - Theory · Physics 2009-09-15 Raman Sundrum

We examine the spectrum of gravitational radiation emitted by a network of cosmic strings, with emphasis on the observational constraints and the opportunities for detection. The analysis improves over past work, as we use a…

Astrophysics · Physics 2009-12-30 R. R. Caldwell , R. A. Battye , E. P. S. Shellard

We present a new formula for the rate at which cosmic strings lose energy into gravitational radiation, valid for all piecewise-linear cosmic string loops. At any time, such a loop is composed of $N$ straight segments, each of which has…

General Relativity and Quantum Cosmology · Physics 2009-10-22 Bruce Allen , Paul Casper

Superconducting cosmic strings emit electromagnetic waves between the times of recombination and reionization. Hence, they have an effect on the global 21cm signal. We compute the resulting absorption features, focusing on strings with…

Cosmology and Nongalactic Astrophysics · Physics 2021-10-27 Roxane Thériault , Jordan T. Mirocha , Robert Brandenberger

We develop a method for computing the linearized gravitational backreaction for Nambu-Goto strings using a fully covariant formalism. We work with equations of motion expressed in terms of a higher dimensional analog of the geodesic…

General Relativity and Quantum Cosmology · Physics 2019-04-24 David F. Chernoff , Éanna É. Flanagan , Barry Wardell

Since general relativity is a consistent low energy effective field theory, it is possible to compute quantum corrections to classical forces. Here we compute a quantum correction to the gravitational potential between a pair of polarizable…

High Energy Physics - Theory · Physics 2016-07-20 L. H. Ford , Mark P. Hertzberg , J. Karouby

We study the relative contribution of cusps and pseudocusps, on cosmic (super)strings, to the emitted bursts of gravitational waves. The gravitational wave emission in the vicinity of highly relativistic points on the string follows, for a…

High Energy Physics - Theory · Physics 2017-08-02 Matthew J. Stott , Thomas Elghozi , Mairi Sakellariadou

Within the closed universe, we obtain the amplitude and frequency of gravitational waves in the terms of discrete wave numbers, wave propagation time, and cosmological constant using the deviation equation in the first-order perturbed…

General Relativity and Quantum Cosmology · Physics 2021-05-27 Jafar Khodagholizadeh , Amir H. Abbassi , Ali Vahedi , Komeil Babaei

We present projected constraints on the cosmic string tension, $G\mu/c^2$, that could be achieved by future gravitational wave detection experiments and express our results as semi-analytic relations of the form $G\mu(\Omega_{\rm…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Sotirios A. Sanidas , Richard A. Battye , Benjamin W. Stappers

We consider Kasner-type static, cylindrically symmetric interior string solutions in the $f\left(R,L_m\right)$ theory of modified gravity. The physical properties of the string are described by an anisotropic energy-momentum tensor…

General Relativity and Quantum Cosmology · Physics 2015-10-07 Tiberiu Harko , Matthew J. Lake

We derive analytic expressions for the interaction energy between two general $U(1)$ cosmic strings as the function of their relative orientation and the ratio of the coupling constants in the model. The results are relevant to the…

High Energy Physics - Phenomenology · Physics 2009-10-28 L. M. A. Bettencourt , R. J. Rivers

The effect of capture of a cosmic object by the central gravitational field of a galaxy cluster is described in the expanding Universe. The cosmic evolution can be the origin of the capture explaining formation of galaxies and their…

Astrophysics · Physics 2007-06-07 Piotr Flin , Victor Pervushin , Andrey Zorin

We consider the possible existence of gravitationally bound stringlike objects in the framework of the generalized hybrid metric-Palatini gravity theory, in which the gravitational action is represented by an arbitrary function of the Ricci…

General Relativity and Quantum Cosmology · Physics 2021-12-21 Hilberto M. R. da Silva , Tiberiu Harko , Francisco S. N. Lobo , João Luís Rosa

The string model of gravitational force is proposed where the string forms the mediation of the gravitational interaction between two gravitating bodies. It reproduces the Newtonian results in the first-order approximation and it predicts…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Miroslav Pardy