The next cosmology seminar takes place on Friday 30th of
September, seminar room E349 at 2pm. Our guest speaker will be
Nilanjandev Bhaumik from the Indian Institute of Science (Bangalore, India).
Cosmic Inflation, the most favoured scenario of the early Universe,
implies that all forms of matter and radiation observed today are the
outcome of quantum fluctuations occurring around the event horizon of a
exponentially fast accelerating space-time. Clearing the ground for
the incoming spatial and ground based cosmological observations,
Christophe have derived, at an
unprecedented level of precision, the shape of the expected power
spectra of both the quantum-generated gravitational waves and
Anticipating the opening of the Brout-Englert-Lemaître Center, a few
aesthetic pictures associated with our researches will be on display
during the “Walk in the Park” event, on Saturday the 25th at the
Tournay Solvay Park (11am).
A cosmic strings network present in our Universe should be incessantly
emitting gravitational waves. An absolute lower limit of the expected
signal can be found by determining the gravitational waves created
by the back bones of the network: the long cosmic
strings. Disrael and Christophe, in collaboration with
François R. Bouchet, have
computed this irreducible contribution using new numerical
simulations of Nambu-Goto cosmic strings.
As our Universe has expanded and cooled, it is suspected that it has
undergone different phase transitions. In particular, first order
cosmological phase transitions provide a compelling source of
Gravitational Waves (GWs) and this is particularly interesting in the
context of the Laser Interferometer Space Antenna
a recent publication, Pierre and his
collaborators proposed a new accurate semi-analytical model for
predicting the GW signal generated by a turbulent phase in the
aftermath of a first order phase transition.