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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…

General Relativity and Quantum Cosmology · Physics 2009-10-31 U. Sperhake , K. R. P. Sjodin , J. A. Vickers

The evolution of cosmic string networks is an interesting dynamical problem. The equations governing these networks are classical and fully specified, but the length scale at which cosmic string loops form has been uncertain to tens of…

Astrophysics · Physics 2009-06-23 Joseph Polchinski

We examine the effects of cosmic strings on structure formation and on the ionization history of the universe. While Gaussian perturbations from inflation are known to provide the dominant contribution to the large scale structure of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Benjamin Shlaer , Alexander Vilenkin , Abraham Loeb

We critically assess the twin prospects of describing the observed universe in string theory, and using cosmological experiments to probe string theory. For the purposes of this short review, we focus on the limitations imposed by our…

High Energy Physics - Theory · Physics 2015-05-30 C. P. Burgess , Liam McAllister

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…

High Energy Physics - Theory · Physics 2008-11-26 Robert Brandenberger

Cosmic superstrings are expected to be formed at the end of brane inflation, within the context of brane-world cosmological models inspired from string theory. By studying properties of cosmic suprestring networks, and comparing their…

High Energy Physics - Theory · Physics 2008-11-26 Mairi Sakellariadou

The cosmic string scenario in an open universe is developed -- including the equations of motion, a model of network evolution, the large angular scale CMB temperature anisotropy, and the power spectrum of density fluctuations produced by…

Astrophysics · Physics 2009-10-30 P. P. Avelino , R. R. Caldwell , C. J. A. P. Martins

The theory of cosmological perturbations is the main tool which connects theories of the early universe (based on new fundamental physics such as string theory) with cosmological observations. In these lectures, I will provide an…

High Energy Physics - Theory · Physics 2015-06-26 Robert H. Brandenberger

The interplay between string theory and cosmology is very promising. Since string theory will yield a quantum theory of space-time and unify all forces of nature, it has the potential of addressing many of the conceptual problems of the…

High Energy Physics - Theory · Physics 2007-05-23 Robert H. Brandenberger

We compute fermion quantum corrections to the energy of cosmic strings. A number of rather technical tools is needed to formulate this correction and we employ isospin and gauge invariance to verify consistency of these tools. These…

High Energy Physics - Theory · Physics 2017-04-03 H. Weigel

Inflation of cosmic gauge and global strings is investigated by numerically solving the combined Einstein and field equations. Above some critical symmetry-breaking scales, the strings undergo inflation along the radial direction as well as…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Inyong Cho

In spite of the phenomenological successes of the inflationary universe scenario, the current realizations of inflation making use of scalar fields lead to serious conceptual problems which are reviewed in this lecture. String theory may…

High Energy Physics - Theory · Physics 2009-11-11 Robert H. Brandenberger

String theory counterparts to Einstein's gravity, cosmology and inflation are described. A very tight upper bound on the Cosmic Gravitational Radiation Background (CGRB) of standard inflation is shown to be evaded in string cosmology, while…

High Energy Physics - Theory · Physics 2007-05-23 G. Veneziano

A class of well-motivated models of inflation end by producing cosmic strings. The current status of efforts to calculate and observe the signals from such models are outlined, with a particular emphasis on cosmic strings, and on the Cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Mark Hindmarsh

The search for cosmic strings has been of renewed interest with the advent of precision cosmology. In this note we give a quantitative description of the nonlinear matter density fluctuations that can form from a scaling network of cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-06 Francis Duplessis , Robert Brandenberger

We derive analytic expressions for the interaction energy between two general $U(1)$ cosmic strings as the function of their relative orientation and the ratio of the coupling constants in the model. The results are relevant to the…

High Energy Physics - Phenomenology · Physics 2009-10-28 L. M. A. Bettencourt , R. J. Rivers

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

Inflationary cosmology has provided a predictive and phenomenologically very successful scenario for early universe cosmology. Attempts to implement inflation using scalar fields, however, lead to models with serious conceptual problems. I…

Astrophysics · Physics 2007-05-23 Robert H. Brandenberger

In this review, a number of approaches to superstring cosmology which make use of key features which distinguish string theory from point particle theories are discussed, with particular emphasis on emergent scenarios. One motivation for…

High Energy Physics - Theory · Physics 2023-10-31 Robert Brandenberger

This is a pedagogical introduction to the basics of the cosmic string theory and also a review of the recent progress made with respect to the macrophysical predictions of the theory. Topics covered include, string formation and evolution,…

Astrophysics · Physics 2009-09-25 L. Perivolaropoulos