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Related papers: String Evolution in Open Universes

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We develop an analytic model to quantitatively describe the evolution of superconducting cosmic string networks. Specifically, we extend the velocity-dependent one-scale (VOS) model to incorporate arbitrary currents and charges on cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-03 C. J. A. P. Martins , Patrick Peter , I. Yu. Rybak , E. P. S. Shellard

The dynamics of string junctions and their influence on the evolution of cosmic superstring networks are studied in full detail. We review kinematic constraints for colliding strings in a Friedmann-Lema\^itre-Robertson-Walker background and…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-27 I. Yu. Rybak , A. Avgoustidis , C. J. A. P. Martins

Cosmic strings are topological defects possibly formed in the early Universe, which may be observable due to their gravitational effects on the cosmic microwave background radiation or gravitational wave experiments. To this effect it is…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-01 R. P. L. Azevedo , C. J. A. P. Martins

We extend and develop our previous work on the evolution of a network of cosmic strings. The new treatment is based on an analysis of the probability distribution of the end-to-end distance of a randomly chosen segment of left-moving string…

High Energy Physics - Phenomenology · Physics 2016-09-01 Daren Austin , E. J. Copeland , T. W. B. Kibble

Cosmic strings are topological defects arising in a variety of cosmological scenarios, as the Universe undergoes symmetry-breaking phase transitions, whose discovery would offer valuable insight into the high-energy physics that shaped the…

High Energy Physics - Phenomenology · Physics 2026-02-27 P. B. Barbosa , C. J. A. P. Martins

Evolution of winding strings in spacetimes with cycles whose proper lengths depend on time is examined. It was established earlier that extended objects wrapping the shrinking dimension in compactified Milne spacetime enjoy classically…

High Energy Physics - Theory · Physics 2007-05-23 Marek Pawlowski , Wlodzimierz Piechocki , Michal Spalinski

We consider the effective action for strings and describe in detail the evolution of a four dimensional homogeneous isotropic universe with matter included. We find that the evolution, which is singular in general, becomes singularity free…

High Energy Physics - Theory · Physics 2009-10-30 S. Kalyana Rama

We set up and analyse a model for the non-equilibrium evolution of a network of cosmic strings initially containing only loops and no infinite strings. Due to this particular initial condition, our analytical approach differs significantly…

High Energy Physics - Phenomenology · Physics 2009-10-31 E. J. Copeland , T. W. B. Kibble , D. A. Steer

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

Cosmic (super)strings offer promising ways to test ideas about the early universe and physics at high energies. While in field theory constructions their tension is usually assumed to be constant (or at most slowly-varying), this is often…

High Energy Physics - Phenomenology · Physics 2025-05-08 Filippo Revello , Gonzalo Villa

We obtain the equations of motion for cosmic strings in extensions of the 3+1 FRW model with extra dimensions. From these we derive a generalisation of the Velocity-dependent One-Scale (VOS) model for cosmic string network evolution which…

High Energy Physics - Phenomenology · Physics 2009-11-10 A. Avgoustidis , E. P. S. Shellard

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

We develop a model of string dynamics with back-reaction from both scaling and non-scaling loops taken into account. The evolution of a string network is described by the distribution functions of coherence segments and kinks. We derive two…

High Energy Physics - Theory · Physics 2010-11-19 Vitaly Vanchurin

A model of a cloud formed by massive strings is used as a source of Bianchi type II. We assumed that the expansion $(\theta)$ in the model is proportional to the shear $(\sigma)$. To get exact solution, we have considered the equation of…

General Physics · Physics 2015-06-12 Hassan Amirhashchi

The properties of string networks at scales well below the horizon are poorly understood, but they enter critically into many observables. We argue that in some regimes, stretching will be the only relevant process governing the evolution.…

High Energy Physics - Phenomenology · Physics 2008-11-26 Joseph Polchinski , Jorge V. Rocha

The charge-velocity-dependent one-scale model is an extension of the canonical velocity-dependent one-scale model which explicitly incorporates additional degrees of freedom on the string worldsheet, such as arbitrary currents and charges,…

High Energy Physics - Phenomenology · Physics 2025-06-27 F. C. N. Q. Pimenta , 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

We describe the detailed study and results of high-resolution numerical simulations of string-induced structure formation in open universes and those with a non-zero cosmological constant. The effect from small loops generated from the…

Astrophysics · Physics 2009-09-25 J. H. P. Wu , P. P. Avelino , E. P. S. Shellard , B. Allen

A complete qualitative study of the dynamics of string cosmologies is presented for the class of isotopic curvature universes. These models are of Bianchi types I, V and IX and reduce to the general class of Friedmann-Robertson-Walker…

High Energy Physics - Theory · Physics 2009-10-31 Andrew P. Billyard , Alan A. Coley , James E. Lidsey

We use the Velocity-dependent One Scale Model for topological defect evolution to explore and classify the possible scaling solutions for string networks with time-varying tension, in cosmological and non-cosmological settings and under two…

High Energy Physics - Phenomenology · Physics 2026-02-24 C. S. C. M. Coelho , A. -L. Y. Gschrey , C. J. A. P. Martins