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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

In this paper we discuss a possible cosmological time evolution of fundamental constants from the theoretical and experimental point of views. On the theoretical side, we explain that such a cosmological time evolution is actually something…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Xavier Calmet , Matthias Keller

We evolve the network of global strings in the matter-dominated universe by means of numerical simulations. The existence of the scaling solution is confirmed as in the radiation-dominated universe but the scaling parameter $\xi$ takes a…

High Energy Physics - Phenomenology · Physics 2009-12-30 Masahide Yamaguchi , Jun'ichi Yokoyama , M. Kawasaki

We study the behaviour and consequences of cosmic string networks in contracting universes. They approximately behave during the collapse phase as a radiation fluids. Scaling solutions describing this are derived and tested against…

Astrophysics · Physics 2015-06-24 P. P. Avelino , C. J. A. P. Martins , C. Santos , E. P. S. Shellard

In the modified measure formulation the string tension appear as an additional dynamical degree of freedom and these tensions are not universal, but rather each string generates its own tension, which can have a different value for each…

High Energy Physics - Theory · Physics 2021-05-10 E. I. Guendelman

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

I report on recent numerical simulations of the simplest field theory with cosmic string solutions, the Abelian Higgs model. We find that random networks of string quickly converge to a scaling solution in which the network scale length…

High Energy Physics - Phenomenology · Physics 2016-10-26 Mark Hindmarsh

We investigate the evolution of a superconducting string network with arbitrary, constant string current in the friction dominated regime. In the absence of an external magnetic field the network always reaches a scaling solution. However,…

High Energy Physics - Phenomenology · Physics 2008-11-26 Konstantinos Dimopoulos , Anne-Christine Davis

We investigate a static, cylindrically symmetric cosmic string on the brane without a perturbative approximation. We find there could be a (large) enhancement of the (effective) string tension when the energy density at the center of the…

High Energy Physics - Theory · Physics 2023-04-12 Chia-Min Lin

We discuss and summarise the predictions of a model for the non-equilibrium evolution of a network of cosmic strings initially containing {\em only loops} and {\em no infinite strings}. The results are of interest given recent work…

High Energy Physics - Phenomenology · Physics 2007-05-23 D. A. Steer

We discuss some aspects of string cosmology with an emphasis on the role played by the dilaton. A cosmological scenario based on the assumption that all spatial dimensions are periodic so that winding modes play an important role is…

High Energy Physics - Theory · Physics 2007-05-23 A. A. Tseytlin

Motivated by recent developments in superstring theory in the cosmological context, we examine a field theory which contains string networks with 3-way junctions. We perform numerical simulations of this model, identify the length scales of…

High Energy Physics - Theory · Physics 2009-11-11 Mark Hindmarsh , P. M. Saffin

Theories of the cosmological constant fall into two classes, those in which the vacuum energy is fixed by the fundamental theory and those in which it is adjustable in some way. For each class we discuss key challenges. The string theory…

High Energy Physics - Theory · Physics 2007-05-23 Joseph Polchinski

We investigate some classical aspects of fundamental strings via numerical experiments. In particular, we study the thermodynamics of a string network within a toroidal universe, as a function of string energy density and space…

High Energy Physics - Theory · Physics 2009-10-28 Mairi Sakellariadou

We review the properties and evolution of strings networks containing both a spectrum of string tensions as well as Y-junctions, namely a point at which three different strings meet. Such a situation is expected in cosmic superstring…

High Energy Physics - Theory · Physics 2015-06-17 D. A. Steer

The implications of string theory for understanding the dimension of uncompactified spacetime are investigated. Using recent ideas in string cosmology, a new model is proposed to explain why three spatial dimensions grew large. Unlike the…

High Energy Physics - Theory · Physics 2010-11-01 Gerald B. Cleaver , Philip J. Rosenthal

Semilocal strings -- a particular limit of electroweak strings -- are an interesting example of a stable non-topological defect whose properties resemble those of their topological cousins, the Abrikosov-Nielsen-Olesen vortices. There is,…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-01 A. Achucarro , A. Avgoustidis , A. Lopez-Eiguren , C. J. A. P. Martins , J. Urrestilla

We motivate the study of chiral cosmic strings through a scenario of structure formation which mixes D-term inflation and strings. We then discuss some properties of chiral cosmic strings, and results regarding their evolution and possible…

Astrophysics · Physics 2009-10-31 D. A. Steer

The topic of cosmic strings provides a bridge between the physics of the very small and the very large. They are predicted by some unified theories of particle interactions. If they exist, they may help to explain some of the largest-scale…

High Energy Physics - Phenomenology · Physics 2010-11-01 M. B. Hindmarsh , T. W. B. Kibble

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