Stochastic gravitational waves from long cosmic strings

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.

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Gravitational waves from freely decaying turbulence

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 LISA. In 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.

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Cosmology Seminar

The next cosmology seminar takes place on Thursday 19th of May, seminar room E349 at 11am. Our guest speaker will be Hugo Roussille from APC (Paris, France).

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Cosmology Seminar

The next cosmology seminar takes place on Thursday 7th of April, seminar room E349 at 11am. Our guest speaker will be Fabien Lacasa from the Institut d’Astrophysique Spatiale (Orsay, France).

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Gravitational multifield dynamics on Higgs pre-inflation and preheating

Traditionally the problem of initial conditions for inflation has been treated separately from studies of reheating. To allow for a parametric-type reheating, the inflaton must be allowed to interact with (or decay to) other fields, and, these interactions should be present also during inhomogeneous preinflation. Could they prevent cosmic inflation to start in the first place? In a single-author publication Cristian answers this question for Higgs Inflation: once more, inflation always starts and passes the challenge!

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