astro-ph/0110285

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TOPOLOGICAL DEFECTS IN COSMOLOGY 1

Alejandro Gangui


Instituto de Astronomía y Física del Espacio,
Ciudad Universitaria, 1428 Buenos Aires, Argentina

and

Dept. de Física, Universidad de Buenos Aires,
Ciudad Universitaria - Pab. I, 1428 Buenos Aires, Argentina


Abstract. Topological defects are ubiquitous in condensed-matter physics but only hypothetical in the early universe. In spite of this, even an indirect evidence for one of these cosmic objects would revolutionize our vision of the cosmos. We give here an introduction to the subject of cosmic topological defects and their possible observable signatures. Beginning with a review of the basics of general defect formation and evolution, we then focus on mainly two topics in some detail: conducting strings and vorton formation, and some specific imprints in the cosmic microwave background radiation from simulated cosmic strings.


Table of Contents

INTRODUCTION
How defects form
Phase transitions and finite temperature field theory
The Kibble mechanism
A survey of topological defects
Conditions for their existence: topological criteria

DEFECTS IN THE UNIVERSE
Local and global monopoles and domain walls
Are defects inflated away?
Cosmic strings
String loops and scaling
Global textures
Evolution of global textures

CURRENTS ALONG STRINGS
Goto--Nambu Strings
Witten strings
Superconducting strings !
Macroscopic string description
The dual formalism
The Future of the Loops

STRUCTURE FORMATION FROM DEFECTS
Cosmic strings
Textures

CMB SIGNATURES FROM DEFECTS
CMB power spectrum from strings
CMB bispectrum from active models
CMB bispectrum from strings
CMB polarization

VARIA
Astrophysical footprints
Cosmology in the Lab
Gravitational waves from strings
More cosmological miscellanea

REFERENCES



1 Lecture Notes for the First Bolivian School on Cosmology, La Paz, 24-28 September, 2001. http://www.umsanet.edu.bo/fisica/cosmo2k1.html Back.

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