La campagne présidentielle 2022 se joue dans un contexte économique, sanitaire et géopolitique très particulier. Deux ans après l'émergence de la Covid-19, l'épidémie se poursuit au gré de l'apparition de nouveaux variants. La reprise se confirme dans l'ensemble des zones géographiques malgré la vague Omicron qui a contraint les gouvernements à pre...
Published in Classical and Quantum Gravity
We propose a mechanism for generating an inflationary phase in the early universe without resorting to any type of scalar field(s). Instead, this accelerated expansion is driven by a dynamical ‘cosmological constant (CC)’ in the framework of unimodular gravity (UG). The time dependent CC can be related to an energy diffusion term that arises natura...
Published in Journal of Cosmology and Astroparticle Physics
Here, Primordial Black Holes (PBHs) creation from exponential potential has been inquired, through gravitationally raised friction emanated from the nonminimal coupling between gravity and field derivative setup. Setting a two-parted exponential function of inflaton field as coupling parameter, and fine-tuning of four parameter Cases of our model, ...
Most of the phenomenology of loop quantum gravity in the cosmological sector is based on the so-called holonomy correction to the Hamiltonian constraint. It straightforwardly modifies the Friedmann equations. In this work, we investigate the influence of corrections generalizing the one usually used in loop quantum cosmology. We find that a long en...
Published in Journal of Cosmology and Astroparticle Physics
In this paper, we consider a scenario of spontaneous baryogenesis in a framework of warm quintessential inflation where the residual inflaton field, left out after warm inflation, plays the role of quintessence field at late times and is coupled to a non-conserved baryonic current. Assuming a four fermion (B – L) violating effective interaction, we...
Published in Journal of Cosmology and Astroparticle Physics
We study several extensions of the Starobinsky model of inflation, which obey all observational constraints on the inflationary parameters, by demanding that both the inflaton scalar potential in the Einstein frame and the F(R) gravity function in the Jordan frame have the explicit dependence upon fields and parameters in terms of elementary functi...
Published in Journal of Cosmology and Astroparticle Physics
We present the first lattice simulation to investigate the nature of multi-stream inflation. The simulation confirms the physical picture of multi-stream inflation, and with new findings in parameter space and field behaviors. Our simulation shows that gradient energy plays a significant role in multi-stream inflation. For a double field potential ...
Published in Journal of Cosmology and Astroparticle Physics
When the inflaton couples to photons and amplifies electric fields, charged particles produced via the Schwinger effect can dominate the universe after inflation, which is dubbed as the Schwinger preheating. Using the hydrodynamic approach for the Boltzmann equation, we numerically study two cases, the Starobinsky inflation model with the kinetic c...
Published in Journal of Cosmology and Astroparticle Physics
We consider the production of dark matter during the process of reheating after inflation. The relic density of dark matter from freeze-in depends on both the energy density and energy distribution of the inflaton scattering or decay products composing the radiation bath. We compare the perturbative and non-perturbative calculations of the energy d...
Published in Journal of Cosmology and Astroparticle Physics
Strongly non-geodesic, or rapidly turning trajectories in multifield inflation have attracted much interest recently from both theoretical and phenomenological perspectives. Most models with large turning rates in the literature are formulated as effective field theories. In this paper we investigate rapid-turn inflation in supergravity as a first ...
