Poster
T. O. Miranda, L. Sousa
Abstract
Cosmic strings are hypothetical topological objects predicted by many
Grand Unified Theory models, thought to be produced in the early Universe, due to a symmetry
breaking phase transition. During their evolution, they often interact with each other, leading to
the formation of discontinuities in the string tangent, known as kinks, and of closed loops of
strings. Cosmic string networks are expected to survive throughout the history of the Universe,
leaving behind observational imprints, such as the Stochastic Gravitational Wave Background
(SGWB). When a loop is formed, it detaches from the network and loses energy in the form of
Gravitational Waves (GWs). The superposition of all their emissions generates the SGWB. The
power spectrum of the SGWB generated by loops has been computed for different cosmic string
models ([1] and [2]). However, kinks are also expected to decay by emitting gravitational waves,
but their contributions are often neglected in computations of the spectrum. The main goal of
this work is to develop a framework to study the contributions of kinks to the SGWB. Methods:
This will be achieved by extending existing models in the literature that describe the small-scale
structure ([3] and [4]), to include all relevant aspects to study this GW emission, starting by
developing an effective model to describe the evolution of the small-scale structure and its
impact on the network dynamics, so that it can later be used to study the contributions of kink
decay to the spectrum of the SGWB. Results: We hope to develop a framework that will allow
us to not only quantify the impact of small-scale structure in the SGWB, but also on the SGWB
generated by loops. (This is still ongoing work). Conclusions: We expect that this framework will
make possible to quantify the uncertainties associated with the computation of the SGWB due
to the small-scale structure, leading to more precise predictions of this observational signature.
IJUP 2024
Porto, Portugal
2024 May
