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Journal-club Doctorants / Journal-club PhD students

« Probing Grand Unified Theories with topological defects in Cosmology »

Erwan Allys
PhD Student -

Despite the fact that they have not yet been observed in astrophysical and cosmological observations, topological defects still are an unavoidable consequence of most of our high energy physical models. Thus, we must understand why we don't see them, what consequences this non-observation has on high energy physics, and if it will be possible to observe them in the future.
To introduce the subject, we will discuss the concept of (local) symmetry in particle physics. It will permit to introduce in a very general way the Grand Unified theories, which describe the particle physics at high energy, and to understand how these theories reduce to the standard model of particle physics at lower energy, due to the phenomena of spontaneous symmetry breaking. We will then discuss the different kinds of topological defects, and how they form, using various examples of the everyday life in condensed media and liquid crystals. Finally, we will discuss the formation and consequences of topological defects in a cosmological context, focusing on the cosmic strings.
During the whole talk we will try to keep an elementary mathematical formalism and to focus on the underlying physical concepts.
jeudi 29 octobre 2015 - 17:00
Salle Entresol Daniel Chalonge, Institut d'Astrophysique
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