We investigate the influence of a time-varying spacetime background on the vacuum polarization of a massless quantum field confined to a Casimir cavity. The background is modelled as an anisotropic Bianchi-I spacetime, in which small time-dependent perturbations around the flat spacetime are vanishing in the far past and future. The spacetime admits asymptotic Minkowskian regions, thus...
Recently, the cosmographic approach has gained considerable interest as a model-independent technique that can describe the recent expansion of the universe. In fact, given only the observational assumptions of the cosmological principle, it makes it possible to study such an evolution without assuming a specific cosmological model. In this talk I will show some of the most promising lines of...
One of the most debated issues in astrophysics is the discrepancy, which ranges between 4 to 6 sigma, between the locally estimated value of the Hubble constant using the SNeIa distance scale calibrated with Classical Cepheids and the cosmological value derived from Cosmic Microwave Background Radiation (CMBR). This problem is commonly referred to as the Hubble constant tension and represents...
We discuss the generalization of gravitational energy-momentum pseudo-tensor to Extended Theories of Gravity, in particular to higher-order theories in curvature invariants. This result is achieved by imposing that the local variation of gravitational action of any order vanishes under rigid translations. We also prove that this tensor, in general, is not covariant but only affine, that is, it...
In this talk, I give a definition for the phenomenological tomogram of the universe. I introduce the theoretical classical and quantum tomograms. I show how we could investigate the primordial quantum state of the universe from the possible deviations of the phenomenological tomogram from the classical tomogram.
