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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

We discuss the cosmological evolution of cosmic strings with time-dependent tension. We show that, in the case that the tension changes as a power of time, the cosmic string network obeys the scaling solution: the characteristic scale of…

High Energy Physics - Phenomenology · Physics 2009-11-11 Masahide Yamaguchi

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 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

We provide a general overview of the velocity-dependent one-scale model for cosmic string evolution and discuss two further extensions to it. We introduce and justify a new ansatz for the momentum parameter $k$, and also incorporate the…

High Energy Physics - Phenomenology · Physics 2014-11-17 C. J. A. P. Martins , E. P. S. Shellard

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 stability of superconducting strings in a U(1)_{local} x U(1)_{global} model coupled via a gauge field interaction term to U(1) Abelian-Higgs strings. The effect of the interaction on current stability is numerically…

High Energy Physics - Theory · Physics 2013-05-30 Alexandru Babeanu , Betti Hartmann

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

The velocity-dependent `one-scale' model of Martins and Shellard is used to study the evolution of a cosmic string network (and the corresponding loop population) in open universes. It is shown that in this case there is no linear scaling…

Astrophysics · Physics 2009-10-30 C. J. A. P. Martins

We study the interaction of several types of static straight cosmic strings, including local strings, global strings, and bosonic superconducting strings with and without magnetic currents. First, we evaluate the interaction energy of two…

High Energy Physics - Phenomenology · Physics 2023-09-12 Kohei Fujikura , Siyao Li , Masahide Yamaguchi

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 study the effects of friction on the scaling evolution of string networks in condensed matter and cosmological contexts. We derive a generalized `one-scale' model with the string correlation length $L$ and velocity $v$ as dynamical…

High Energy Physics - Phenomenology · Physics 2016-09-01 C. J. A. P. Martins , E. P. S. Shellard

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 describe a method for simulating the dynamics of an $S_3$ cosmic string network. We use a lattice Monte Carlo to generate initial conditions for the network, which subsequently is allowed to relax continuously according to a simplified…

High Energy Physics - Theory · Physics 2007-05-23 Patrick McGraw

It has recently been realised that strings with time-dependent tensions exhibit interesting dynamics; in particular, when the tension decreases loops of string can grow and possibly percolate. We extend previous analytic studies of strings…

High Energy Physics - Theory · Physics 2026-01-09 Hubert Lau Sze Chun , Joseph Conlon

We investigate the Hagedorn transitions of string networks with Y-junctions as may occur, for example, with (p,q) cosmic superstrings. In a simplified model with three different types of string, the partition function reduces to three…

High Energy Physics - Theory · Physics 2008-12-18 R. J. Rivers , D. A. Steer

We study, within the Nambu-Goto approximation, the stability of massive string junctions under the influence of the tensions of three strings joining together in a Y-type configuration. The relative angle $\beta$ between the strings at the…

High Energy Physics - Theory · Physics 2015-06-23 A. Avgoustidis , A. Pourtsidou , M. Sakellariadou

A novel mechanism to produce a cosmic network of fundamental superstrings based on a time-varying string tension has been recently proposed. It has been found that fundamental superstrings can grow in a kinating background driven by the…

High Energy Physics - Theory · Physics 2025-11-24 Luca Brunelli

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

In this letter we give specific examples of Z_N Lotka-Volterra competition models leading to the formation of string networks. We show that, in order to promote coexistence, the species may arrange themselves around regions with a high…

Adaptation and Self-Organizing Systems · Physics 2015-06-16 P. P. Avelino , D. Bazeia , J. Menezes , B. F. de Oliveira