Seminarium Teorii Względności i Grawitacji

I will apply the Dirac procedure for constrained systems to the Arnowitt–Deser–Misner formalism for cosmological perturbation theory in the Bianchi I universe. I will carefully discuss the issue of gauge-fixing, gauge transformations and spacetime reconstruction. I will find the so called Kuchar parametrization to be well suited for this purpose. Then I will shift my attention to the peculiarities of cosmological perturbations in anisotropic backgrounds such as the evolution of the plane wave wavefronts and the couplings between gravitational waves and matter perturbations. I will show that there exist coordinate systems in which (a polarization mode of) a gravitational wave is represented by the density metric perturbation.Seminar will be also broadcasted via zoom