Title:

Gravitational waves: a window to the early universe

Abstract:

Detection of gravitational waves is one of most challenging tasks of modern cosmology and astrophysics.

Gravitational waves holds the potential for helping re-construct a picture of the universe at energy scales much higher (at times much

earlier) than the picture obtained using cosmic microwave background observations.

I will address different cosmological sources for the stochastic gravitational waves background – present in the very early universe (quantum mechanical fluctuations during inflation in models beyond standard scenarios including modified (massive) gravity and Chern-Simons gravity models, cosmological phase transitions, long duration primordial hydro- and magnetohydrodynamical (MHD) turbulence), I will discuss the gravitational wave background main characteristics such as typical frequency, the signal strength, and circular polarization degree (for the gravitational waves originated from parity-violating sources such as Chern-Simons gravity, chiral MHD turbulence), and I will address detection prospects.