2021-04-19
(月) 観測的宇宙論速報
内容：添付ファイル [添付] 参照
Author(s)TitleYear, Journal,Number(,Link)Y. SutoJinsei Ippan ni Sotairon2010, ISBN978-4-13-063354-3
2021-04-19
(月) 初期宇宙・相対論速報UTAPwiki/セミナー/初期宇宙・相対論速報
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Title: Dark Matter and Inflation in Einstein-Cartan Gravity †
↑Speaker: Inar Timiryasov †
Abstract: It is known that the gravitational force can be obtained by gauging the Poincaré group. Once the resulting theory – Einstein-Cartan gravity – is coupled to matter, its action contains more terms of mass dimension at most 4 than metric gravity. In this talk, I will discuss them and explore two phenomenological consequences. First, Einstein-Cartan theory generalizes inflationary scenarios driven by the Higgs field. As in the known metric and Palatini models, the resulting predictions agree with observations. Secondly, we obtain a new mechanism for producing singlet fermions in the Early Universe. In a large range of masses, these fermions can constitute all of the dark matter.
The seminar will be preceded by three short (one hour) lectures introducing Einstein-Cartan theory and other required tools.
References:
https://arxiv.org/abs/2007.14978
https://arxiv.org/abs/2007.16158
https://arxiv.org/abs/2008.11686
2021-04-22
(木) 宇宙物理学セミナーUTAPwiki/セミナー/宇宙物理学セミナー
Speaker:Kohei Fujikura
Title:
Cosmological phase transitions in physics beyond the Standard Model of particle physics
Abstract:
Since the very early universe is filled with thermal plasma, the thermal effect plays an important role. When the temperature of the universe is sufficiently higher than a certain scale of a symmetry breaking, a broken symmetry is restored. As the temperature decreases due to the cosmic expansion, cosmological phase transitions associated with rearrangement of the ground state take place. If cosmological phase transitions are of the first order, they proceed via nucleations of bubbles. They expand and eventually coalesce with each other until they fill the universe. During this process, stochastic gravitational wave backgrounds are generated by bubble collisions, sound waves and turbulence of thermal plasma. In this seminar, I will mainly discuss the dynamics of cosmological phase transitions as well as the production of stochastic gravitational wave backgrounds realized in theories beyond the Standard Model of particle physics.
2021-04-26
(月) 観測的宇宙論速報
内容：添付ファイル [添付] 参照
Author(s)TitleYear, Journal,Number(,Link)Y. SutoJinsei Ippan ni Sotairon2010, ISBN978-4-13-063354-3
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