Gravitons radiated from light, evaporating black holes contribute to the stochastic
background of gravitational waves. The spectrum of such emission depends on both the …

We consider a modification to the standard cosmological history consisting of introducing a
new species ϕ whose energy density red-shifts with the scale factor a like ρ ϕ∝ a−(4+ n) …

The Brans-Dicke-like field of scalar-tensor gravity can be described as an imperfect fluid in
an approach in which the field equations are regarded as effective Einstein equations. After …

A scalar-tensor theory of gravity, containing an arbitrary coupling function F (ϕ) and a
general potential V (ϕ), is considered in the context of a spatially flat Friedmann-Lemaître …

We study a phenomenological dark energy model which is rooted in the Veneziano ghost of
QCD. In this dark energy model, the energy density of dark energy is proportional to Hubble …

Nongaussian statistics are a powerful discriminant between inflationary models, particularly
those with noncanonical kinetic terms. Focusing on theories where the Lagrangian is an …

It is widely acknowledged that, for formal purposes, a minimally coupled scalar field is
equivalent to an effective perfect fluid with equation of state determined by the scalar …

We study inflationary perturbations in multiple-field models, for which ζ typically evolves until
all isocurvature modes decay—the" adiabatic limit". We use numerical methods to explore …

If the Universe's energy density was dominated by a fast-rolling scalar field while the
radiation bath was hot enough to thermally produce dark matter, then dark matter with larger …

We investigate the gauge-invariant cosmological perturbations in the gravity and matter
frames in the general scalar–tensor theory where two frames are related by the disformal …