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The relativistic Friedmann Lemaitre cosmology model (FLCM) is very sucessful to describe the evolution history of the Universe from the " First three Minutes". Any alternative model should be consistent with the FLCM explanations to the…

High Energy Physics - Phenomenology · Physics 2009-11-07 Xinhe Meng , Jingmin Hou , Kaiyi Lu , Wenyao Zhao

We describe a numerical simulation of the evolution of an $S_3$ cosmic string network which takes fully into account the non-commutative nature of the cosmic string fluxes and the topological obstructions which hinder strings from moving…

Astrophysics · Physics 2009-10-30 Patrick N. McGraw

We have studied the cosmological evolution of domain wall networks in two, three and four spatial dimensions using high-resolution field theory simulations. The dynamical range and number of our simulations is larger than in previous works,…

High Energy Physics - Phenomenology · Physics 2009-11-10 J. C. R. E. Oliveira , C. J. A. P. Martins , P. P. Avelino

Cosmic strings may have formed in the early universe due to the Kibble mechanism. While string networks are usually modeled as being of Nambu-Goto type, this description is understood to be a convenient approximation, which neglects the…

Cosmology and Nongalactic Astrophysics · Physics 2021-09-01 A. R. R. Almeida , C. J. A. P. Martins

We study the dynamics of circular cosmic string loops in a spatially flat Friedmann Lema\^itre Robertson Walker universe within a fractional Polyakov framework that incorporates nonlocal memory effects. Allowing both the loop radius and…

High Energy Physics - Theory · Physics 2026-04-30 Pankaj Chaturvedi , Bikram Nath

We consider the evolution of a network of strings in an expanding universe, allowing for the formation of junctions between strings of different tensions. By explicitly including, in the velocity-dependent evolution equations for the…

High Energy Physics - Phenomenology · Physics 2010-04-06 A. Avgoustidis , E. J. Copeland

A field-theoretical model for non-singular global cosmic strings is presented. The model is a non-linear sigma model with a potential term for a self-gravitating complex scalar field. Non-singular stationary solutions with angular momentum…

High Energy Physics - Theory · Physics 2010-11-19 Y. Verbin , A. L. Larsen

A range of cosmological observations demonstrate an accelerated expansion of the Universe, and the most likely explanation of this phenomenon is a cosmological constant. Given the importance of understanding the underlying physics, it is…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-07 Karoline Loeve , Kristine Simone Nielsen , Steen H. Hansen

An analytic model of long string network evolution, recently developed by the authors, is presented in detail, and modified to describe string loop evolution. By treating the average string velocity, as well as the characteristic…

High Energy Physics - Phenomenology · Physics 2011-05-05 C. J. A. P. Martins , E. P. S. Shellard

We clarify the quantitative nature of the cosmological evolution of a global string network, that is, the energy density, peculiar velocity, velocity squared, Lorentz factor, formation rate of loops, and emission rate of Nambu-Goldstone…

High Energy Physics - Phenomenology · Physics 2009-11-07 Masahide Yamaguchi , Jun'ichi Yokoyama

The canonical velocity-dependent one-scale (VOS) model for cosmic string evolution must be calibrated using high resolution numerical simulations, We exploit our state of the art graphics processing unit accelerated implementation of the…

Cosmology and Nongalactic Astrophysics · Physics 2021-09-22 J. R. C. C. C. Correia , C. J. A. P. Martins

We consider scalar perturbations of energy-density for a class of cosmological models where an early phase of accelerated expansion evolves, without any fine-tuning for graceful exit, towards the standard Friedman eras of observed universe.…

General Relativity and Quantum Cosmology · Physics 2011-05-10 S. Capozziello , G. Lambiase , G. Scarpetta

We describe and numerically test the velocity-dependent one-scale (VOS) string evolution model, a simple analytic approach describing a string network with the averaged correlation length and velocity. We show that it accurately reproduces…

High Energy Physics - Phenomenology · Physics 2009-11-10 C. J. A. P. Martins , J. N. Moore , E. P. S. Shellard

Cosmic string networks form during cosmological phase transitions as a consequence of the Kibble mechanism. The evolution of the simplest networks is accurately described by the canonical Velocity Dependent One-Scale (VOS) model. However,…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-18 A. R. R. Almeida , C. J. A. P. Martins

Previously developed analytic models for the evolution of cosmic string and monopole networks are applied to networks of monopoles attached to two or more strings; the former case is usually known as cosmic necklaces. These networks are a…

High Energy Physics - Phenomenology · Physics 2014-11-21 C. J. A. P. Martins

We apply a recently developed formalism to study the evolution of a current-carrying string network under the simple but generic assumption of a linear equation of state. We demonstrate that the existence of a scaling solution with…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-24 C. J. A. P. Martins , Patrick Peter , I. Yu. Rybak , E. P. S. Shellard

Cylindrically symmetric inhomogeneous magnetized string cosmological model is investigated with cosmological term $\Lambda$ varying with time. To get the deterministic solution, it has been assumed that the expansion ($\theta$) in the model…

General Relativity and Quantum Cosmology · Physics 2014-05-06 Anirudh Pradhan

I use a combination of state-of-the-art numerical simulations and analytic modelling to discuss the scaling properties of cosmic defect networks, including superstrings. Particular attention is given to the role of extra degrees of freedom…

High Energy Physics - Phenomenology · Physics 2015-06-17 C. J. A. P. Martins

We study the evolution of domain wall networks appearing after phase transitions in the early Universe. They exhibit interesting dynamical scaling behaviour which is not yet well understood, and are also simple models for the more…

High Energy Physics - Phenomenology · Physics 2009-11-07 Theodore Garagounis , Mark Hindmarsh

The idea of GUT implies that the universe went through a series of phase transitions during which topological defects are expected to form. We investigate here the genericity of cosmic strings formation in realistic SUSY GUTs models. We…

High Energy Physics - Phenomenology · Physics 2007-05-23 J. Rocher , R. Jeannerot , M. Sakellariadou