Related papers: Using Cosmic Strings to Relate Local Geometry to S…
Global and local symmetries may or may not be restored inside topological defects depending upon the values of the parameters of the model. A detailed study of this parameter dependence of the core structure of strings and monopoles is…
Flat directions are a generic feature of the scalar potential in supersymmetric gauge field theories. They can arise, for example, from D-terms associated with an extra abelian gauge symmetry. Even when supersymmetry is broken softly, there…
We develop a formalism for the quantization of topologically stable excitations in the 4-dimensional abelian lattice gauge theory. The excitations are global and local (Abrikosov-Nielsen-Olesen) strings and monopoles. The operators of…
We describe the detailed study and results of high-resolution numerical simulations of string-induced structure formation in open universes and those with a non-zero cosmological constant. The effect from small loops generated from the…
String cosmology models predict a stochastic cosmic background of gravitational waves with a characteristic spectrum. I describe the background, present astrophysical and cosmological bounds on it, and outline how it may be possible to…
In addition to being a prime candidate for a fundamental unified theory of all interactions in nature, string theory provides a natural setting to understand gauge field theories. This is linked to the concept of "D-branes": extended,…
We use our model of the small scale structure on cosmic strings to develop further the result of Siemens, Olum, and Vilenkin that the gravitational radiation length scale on cosmic strings is smaller than the previously assumed $\Gamma G\mu…
The number of cosmic strings in the observable universe is relevant in determining the probability of detecting such cosmic defects through their gravitational signatures. In particular, we refer to the observation of gravitational lensing…
Local cosmic strings solutions are introduced in a model with a pseudo-anomalous U(1) gauge symmetry. Such a symmetry is present in many superstring compactification models. The coupling of those strings with the axion necessary in order to…
Whilst standard field theoretic Cosmic Strings cannot end, Cosmic Superstrings can form three string junctions, at which each string ends. This opens up a new class of possible boundary conditions for such strings and we show that, at least…
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…
The cosmic string theory for cosmological fluctuations is a good example of healthy scientific progress in cosmology. It is a well defined physically motivated model that has been tested by cosmological observations and has been ruled out…
We investigate the contribution made by small loops from a cosmic string network as seeds for large-scale structure formation. We show that cosmic string loops are highly correlated with the long-string network on large scales and therefore…
Talk given at the ``4th Hellenic School on Elementary Particle Physics", Corfu, 2-20 September 1992: The propagation of strings in cosmological space-time backgrounds is reviewed. We show the relation of a special class of cosmological…
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…
The aim of these lectures is to give an introduction to several topics which lie at the intersection of string theory, gravity theory and gravity phenomenology. One successively reviews: (i) the "membrane" approach to the dissipative…
A natural consequence of string theory is a non-commutative structure of space-time on microscopic scales. The existence of a minimal length, and a modification of the effective field theory are two consequences of this space-time…
Topological defects are involved in a plethora of physical and astrophysical phenomena. In these lectures, I will review the r\^ ole they could play in the large-scale structure formation and the anisotropies of the cosmic microwave…
We give a brief overview of the string landscape and techniques used to construct string compactifications. We then explain how this motivates the notion of the swampland and review a number of conjectures that attempt to characterize…
I discuss some aspects of conformal defects and conformal interfaces in two spacetime dimensions. Special emphasis is placed on their role as spectrum-generating symmetries of classical string theory.