Cosmology and perturbations in massive gravity

Inflaton perturbations in brane-world cosmology with induced gravity

We study cosmological perturbations in the brane models with an induced Einstein-Hilbert term on a brane. We consider an inflaton confined to a de Sitter brane in a five-dimensional Minkowski spacetime. Inflaton fluctuations excite Kaluza-Klein modes of bulk metric perturbations with mass m = −2(2l− 1)(l+ 1)H and m = −2l(2l+ 3)H where l is an integer. There are two branches (± branches) of solu...

Massive neutrinos and cosmology

The present experimental results on neutrino flavour oscillations provide evidence for non-zero neutrino masses, but give no hint on their absolute mass scale, which is the target of beta decay and neutrinoless double-beta decay experiments. Crucial complementary information on neutrino masses can be obtained from the analysis of data on cosmological observables, such as the anisotropies of the...

Massive Neutrinos in Cosmology

There are two places in cosmology where the mass of neutrinos would play a significant role. One is leptogenesis in the early universe, and the other is the evolution of mass density fluctuations that are explored with cosmic microwave background (CMB) fluctuations and the formation of cosmic structure. There is one more place where the presence of neutrinos is generally important — primordial ...

Modified gravity and cosmology

Lorentzian Gravity and Cosmology

If a material vacuum exists, with the properties of a superfluid through which already recognized material moves, then it is capable of acting as a universal reference frame and as an intermediary for the production of particle pairs throughout the universe, which as they cool and recombine, become the source of both high-and low-temperature cosmic background radiation, as observed. Moreover, i...