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In this paper the equation of circular loops of cosmic string with periodic tension is investigated in the Minkowski spacetime and Robertson-Walker universe respectively. We find that the cosmic string loops possessing this kind of…

High Energy Physics - Theory · Physics 2015-06-05 Leilin Wang , Hongbo Cheng

This manuscript investigates a Schwarzschild black hole surrounded by perfect fluid dark matter embedded in a cloud of strings. The effects of its surroundings on thermodynamics, timelike and null geodesics, shadows, and quasinormal modes…

General Relativity and Quantum Cosmology · Physics 2025-03-28 Bilel Hamil , Bekir Can Lütfüoğlu

Cosmic strings inside Schwarzschild black holes in teleparallel gravity are considered.Torsion flux inside the black hole is compute like a torsion vortex on a superfluid.Since some components of torsion are singular on Schwarzschild…

General Relativity and Quantum Cosmology · Physics 2007-05-23 L. C. Garcia de Andrade

We study motion of current-carrying string loops in the field of braneworld spherically symmetric black holes and naked singularities. The spacetime is described by the RN geometry with tidal charge b reflecting the non-local tidal effects…

General Relativity and Quantum Cosmology · Physics 2013-09-27 Z. Stuchlík , M. Kološ

In this letter, we derive the singular condition for black holes and demonstrate the potential resolution of the Schwarzschild black hole singularity in general relativity using non-perturbative $\alpha^{\prime}$ corrections of string…

High Energy Physics - Theory · Physics 2026-02-10 Houwen Wu , Zihan Yan , Shuxuan Ying

Current-carrying string loop dynamics in Schwarzschild-de Sitter spacetimes characterized by the cosmological parameter {\lambda}=1/3{\Lambda}M^2 is investigated. With attention concentrated to the axisymmetric motion of string loops it is…

General Relativity and Quantum Cosmology · Physics 2011-03-23 Martin Kološ , Zdeněk Stuchlík

We construct time-dependent charged black string solutions in five-dimensional Einstein-Maxwell theory. In the far region, the spacetime approaches a five-dimensional Kasner universe with a expanding three-dimensional space and a shrinking…

High Energy Physics - Theory · Physics 2016-01-27 Hideki Ishihara , Masashi Kimura , Ken Matsuno

A method to study electromagnetic (EM) effects generated by a straight null cosmic string moving in classical EM fields is suggested. The string is shown to induce an additional EM field which can be described as a solution to homogeneous…

General Relativity and Quantum Cosmology · Physics 2023-02-15 D. V. Fursaev , I. G. Pirozhenko

We investigate the five and six-dimensional black strings within Einstein-Maxwell theory. The extremal black strings are endowed with the null Killing symmetry. We study the propagation of Einstein-Maxwell modes in the extremal black string…

High Energy Physics - Theory · Physics 2016-09-06 H. W. Lee , Y. S. Myung , Jin Young Kim , D. K. Park

A new model for cosmic strings (i.e. conical singularities) attached to black holes is proposed. These string are obtained by a explicit construction via limiting process from the so-called Bonnor rocket. This reveals quite surprising…

General Relativity and Quantum Cosmology · Physics 2020-09-22 David Kofroň

We continue exploring free strings in the background of null Kasner-like cosmological singularities, following arXiv:0904.4532 [hep-th]. We study the free string Schrodinger wavefunctional along the lines of arXiv:0807.1517 [hep-th]. We…

High Energy Physics - Theory · Physics 2010-04-14 K. Narayan

We study acceleration of current-carrying string loops governed by the presence of an outer tension barrier and an inner angular momentum barrier in the field of Schwarzschild-de Sitter black holes. We restrict attention to the axisymmetric…

General Relativity and Quantum Cosmology · Physics 2012-06-26 Z. Stuchlík , M. Kološ

We study the spectrum of the worldsheet theory of the bosonic closed string in the massless and extremal rotating BTZ black holes. We use a hyperbolic Wakimoto representation of the SL(2,R) currents to construct vertex operators for the…

High Energy Physics - Theory · Physics 2010-01-15 Jamie Parsons , Simon F. Ross

We investigate the evolution of small perturbations around black strings and branes which are low energy solutions of string theory. For simplicity we focus attention on the zero charge case and show that there are unstable modes for a…

High Energy Physics - Theory · Physics 2009-01-23 R. Gregory , R. Laflamme

The BTZ black hole provides a tractable (2+1)-dimensional example for investigating string dynamics in curved spacetime. However, a systematic and robust analysis of the solution space of strings in the near-horizon region of BTZ black…

High Energy Physics - Theory · Physics 2026-05-04 Aritra Banerjee , Arkachur Bhattacharya , Sharang Rajesh Iyer , Ansh Mishra , Priyadarshini Pandit

We study the evolution of strings in the equatorial plane of a Kerr-Newmann black hole. Writting the equations of motion and the constraints resulting from Hamilton's principle, three classes of exact solutions are presented, for a closed…

General Relativity and Quantum Cosmology · Physics 2015-06-25 A. Kuiroukidis , D. B. Papadopoulos

A black hole solution to three dimensional general relativity with a negative cosmological constant has recently been found. We show that a slight modification of this solution yields an exact solution to string theory. This black hole is…

High Energy Physics - Theory · Physics 2010-11-01 Gary T. Horowitz , Dean L. Welch

We suggest that ``free evolution'' integration schemes for the Einstein equations (that do not enforce constraints) may contain exponentially growing modes that render them useless in numerical integrations of black hole spacetimes,…

General Relativity and Quantum Cosmology · Physics 2009-10-28 Carsten Gundlach , Jorge Pullin

We consider a macroscopic charge-current carrying (cosmic) string in the background of a Schwarzschild black hole. The string is taken to be circular and is allowed to oscillate and to propagate in the direction perpendicular to its plane…

High Energy Physics - Theory · Physics 2010-04-06 A. L. Larsen

Recently, an analytical study of radial and circular orbits for null and time-like geodesics that propagate in the spacetime produced by a Schwarzschild black hole associated with cloud of strings, in a universe filled by quintessence, has…

General Relativity and Quantum Cosmology · Physics 2022-07-26 Mohsen Fathi , Marco Olivares , J. R. Villanueva