Related papers: Periodic Cosmic String Formation and Dynamics
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…
The spontaneous breaking of a $U(1)$ symmetry via an intermediate discrete symmetry may yield a hybrid topological defect of \emph{domain walls bounded by cosmic strings}. The decay of this defect network leads to a unique gravitational…
New Developments in String Gravity and String Cosmology are reported: 1-String driven cosmology and its Predictions. 2-The primordial gravitational wave background in string cosmology. 3-Non-singular string cosmologies from Exact Conformal…
We develop the cosmological perturbations formalism in models with a single non-local scalar field originating from the string field theory description of the rolling tachyon dynamics. We construct the equation for the energy density…
Large-scale magnetic fields are observed today to be coherent on galactic scales. While there exists an explanation for their amplification and their specific configuration in spiral galaxies -- the dynamo mechanism -- a satisfying…
We investigate the peculiar velocity field due to long cosmic strings in several cosmological models and analyse the influence of a nonscaling behaviour of the string network, which is expected in open cosmological models or models with a…
Gravitational waves from cosmic strings are generated in the first fractions of a second after the Big Bang, potentially providing a unprecedented probe of the early universe. We discuss the key dynamical processes underlying calculations…
The dynamics of a vortex string, which describes the Nambu-Goldtone modes of the spontaneous breakdown of the target space D=4, N=1 supersymmetry and internal $U(1)_R$ symmetry to the world sheet ISO(1,1) symmetry, is constructed by using…
We show that the r-mode instability can generate strong toroidal fields in the core of accreting millisecond quark stars by inducing differential rotation. We follow the spin frequency evolution on a long time scale taking into account the…
In string theory, the traditional picture of a Universe that emerges from the inflation of a very small and highly curved space-time patch is a possibility, not a necessity: quite different initial conditions are possible, and not…
We consider the decay of cosmic strings that are trapped in the false vacuum in a theory of scalar electrodynamics in 3+1 dimensions. We restrict our analysis to the case of thin-walled cosmic strings which occur when large magnetic flux…
The quantization of circular strings in an anti-de Sitter background spacetime is performed, obtaining a discrete spectrum for the string mass. A comparison with a four-dimensional homogeneous and isotropic spacetime coupled to a conformal…
We give a simple derivation of a new formal expression for the number of particles produced from a conformal scalar field vacuum due to the creation of a gauge cosmic string. We find that the number of particles released in string formation…
In string theory the coupling ``constants'' appearing in the low-energy effective Lagrangian are determined by the vacuum expectation values of some (a priori) massless scalar fields (dilaton, moduli). This naturally leads one to expect a…
Within two specific string cosmology scenarios --differing in the way the pre- and post-big bang phases are joined-- we compute the size and spectral slope of various types of cosmologically amplified quantum fluctuations that arise in…
We study the simultaneous decay of global string loops into scalar particles (massless and massive modes) and gravitational waves (GWs). Using field theory simulations in flat space-time of isolated loops with initial length $\sim 80-1700$…
An implicit, fully characteristic, numerical scheme for solving the field equations of a cosmic string coupled to gravity is described. The inclusion of null infinity as part of the numerical grid allows us to apply suitable boundary…
It is shown that the minimal left-right symmetric model admits cosmic string and domain wall solutions. The cosmic strings arise when the SU(2)_R is broken and can either be destabilized at the electroweak scale or remain stable through the…
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…
For suitable cosmological backgrounds, thermal fluctuations of a gas of strings can generate a scale-invariant spectrum of cosmological fluctuations without requiring a phase of inflationary expansion. We highlight the key points of this…