Published in Journal of Cosmology and Astroparticle Physics
In the context of effective theories of gravity, a minimalist bottom-up approach which takes into account 1-loop quantum corrections leads to modifications in the Einstein-Hilbert action through the inclusion of four extra terms: R 2, CκραβCκραβ , R ln (□) R and Cκραβ ln(□) Cκραβ . The first two terms are necessary to guarantee the renormalizabilit...
Published in Journal of Cosmology and Astroparticle Physics
Primordial non-Gaussianities of the scalar(tensor)-tensor-tensor type supporting a non-trivial squeezed component are known to induce anisotropies in the stochastic gravitational wave background. We derive the explicit form of such anisotropies by making use, for the first time in this context, of the in-in formalism for cosmological correlation fu...
Published in Journal of Cosmology and Astroparticle Physics
Gravitational wave (GW) backgrounds of cosmological origin are expected to be nearly isotropic, with small anisotropies resembling those of the cosmic microwave background. We analyse the case of a scalar-induced GW background and clarify in the process the relation between two different approaches to calculating GW anisotropies. We focus on GW sce...
Published in Journal of Cosmology and Astroparticle Physics
We perform an analytical study of the stability of the background solution [1] of the model in which an inflaton, through an axionic coupling to a U(1) gauge field, causes an amplification of the gauge field modes that strongly backreact on its dynamics. To this goal, we study the evolution of the gauge field modes coupled to the inflaton zero mode...
Published in Journal of Cosmology and Astroparticle Physics
The most robust prediction of inflation driven by a single field is the existence of a red tilt for the spectrum of curvature fluctuations that is experimentally of order 0.04. The tilt is derived solving the exact equation for quantum fluctuations in a quasi de Sitter background with first slow-roll parameter ϵ small but non vanishing. The experim...
Published in Journal of Cosmology and Astroparticle Physics
We implement shifted hybrid inflation in the framework of supersymmetric SU(5) × U(1)χ GUT model which provides a natural solution to the monopole problem appearing in the spontaneous symmetry breaking of SU(5). The U(1)χ symmetry is radiatevely broken after the end of inflation at an intermediate scale, yielding topologically stable cosmic strings...
Published in Journal of Cosmology and Astroparticle Physics
For primordial perturbations, deviations from Gaussian statistics on the tail of the probability distribution can be associated with non-perturbative effects of inflation. In this paper, we present some particular examples in which the tail of the distribution becomes highly non-Gaussian although the statistics remains almost Gaussian in the pertur...
Published in Frontiers in Sustainable Food Systems
The global economy in recent decades has experienced frequent shocks. Many regions must improve their competitiveness and value-added to deal with this. One of them is in the Middle East and North Africa (MENA), where a rise in agricultural value-added (AVA) can produce more jobs than in other sectors. It is necessary to consider increasing AVA in ...
