G. Fanizza, G. Marozzi, M. Medeiros
Abstract
We derive the expressions on the observed light-cone for some relevant cosmological gauge invariant variables, such as the Mukhanov-Sasaki variable and E- and B- modes of the tensor perturbations. Since the structure of the light-cone does not reflect in a direct way the FLRW symmetries, we develop a formalism which is coordinate independent and classifies the perturbations according to their helicities. Even though we work with linear perturbations, our formalism can be readily extended to non-linear theory and put the basis to study the evolution of cosmological perturbations, since the early- until the late-time Universe, directly along the observed light-cone.
Keywords
cosmological perturbation theory, Cosmological perturbation theory in GR and beyond, primordial gravitational waves (theory)
Journal of Cosmology and Astroparticle Physics
Volume 2023, Issue 015, Page 35
2023 June
