Central European Institute for Cosmology and Fundamental Physics
 

Upcoming seminars

23/11/2018, 14:00    Rachel Houtz,  TBA

20/11/2018, 14:00    Andrea Addazi,  Gravitational waves from Dark bubbles in the early Universe

22/11/2018, 16:00    Antonino Marciano,  Non-dynamical torsion from fermions and CMBR phenomenology

26/11/2018, 14:00    Ondrej Pejcha,  Explosive deaths of stars: core-collapse supernovae and stellar mergers

10/12/2018, 14:00    Shinji Mukohyama,  TBA

  

20/11/2018 -- Andrea Addazi (Fudan University, Shanghai)

Time:  14:00

Place: 117 or 226

We will discuss dark matter models which are related to dark first order phase transitions (D.F.O.P.T.) in the early Universe. D.F.O.P.T. sources an efficient materialization of dark bubbles. Dark bubbles can scatter each others producing a gravitational radiation background, detectable in next generation of experiments. We will discuss the specific framework of Majoron dark matter, as a neutrino mass and a Warm Dark Matter genesis model. Majorons may also be detected in next laboratory experiments: i) electron-positron high luminosity colliders; ii) neutrino-less-double-beta decays processes; iii) experiments searching for baryon violating Neutron-Antineutron transitions.



  

22/11/2018 -- Antonino Marciano (Fudan University, Shanghai)

Time:  16:00

Place: 226

We discuss how inflation and bounce cosmology can emerge from a four-fermion interaction induced by torsion. Inflation can arise from coupling torsion to Standard Model fermions, without any need of introducing new scalar particles beyond the Standard Model. Within this picture, the inflaton field can be a composite field of the SM-particles and arises from a Nambu-Jona-Lasinio mechanism in curved space-time, non-minimally coupled with the Ricci scalar. The model we specify predicts small value of the r-parameter, namely r ~ 10-3 - 10-2, which nonetheless would be detectable by the next generation of experiments, including BICEP 3 and the ALI-CMB projects. On the other hand, bouncing cosmology can be also accounted for in terms of fermion condensates, with the remarking appearance of an ekpyrotic phenomenon, which is solely due to the quantum corrections to the fermion potential. We finally argue about the richness of the phenomenological perspective encoded in both the schemes.



  

26/11/2018 -- Ondrej Pejcha (Charles University, Prague)

Time:  14:00

Place: 226

Interest in the transient astronomical sky has increased tremendously thanks to modern time-domain surveys, which have discovered unexpected diversity in previously known phenomena and identified many new classes of transients. I will focus on two types of transients that are important for the nucleosynthesis in the Universe and the evolution of gravitational wave sources. I will argue that the deaths of massive stars marked by core-collapse supernovae are highly sensitive to initial conditions, which leads to a complex pattern of neutron star and black hole formation. Many stars are members of binary systems and their evolution can be significantly affected by a catastrophic interaction, which results in the rapid loss of mass, energy and angular momentum, and sometimes even merger of the binary star. This phase was recently connected to a newly identified group of red transients. I will present surprising findings from the theoretical interpretation of observations of these red transients.