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A massive vector field is a highly promising candidate for dark matter in the Universe. A salient property of dark matter is its negligible or null coupling to ordinary matter, with the exception of gravitational interaction. This poses a…
String theory has strong implications for cosmology: it tells us that we cannot have a cosmological constant, that single-field slow-roll inflation is ruled out, and that black holes decay. We elucidate the origin of these statements within…
We describe a simple and efficient mechanism by which very heavy particles are copiously created from a primordial inflationary epoch. It works for scalar fields which are massless or very light during inflation and acquire a large mass…
In this letter, we explore the phenomenological impact of inflationary gravitational particle production in the physics of Dark Matter (DM). Large-scale DM fluctuations generated during inflation behave as gravitational particles upon their…
The discovery of dark energy (DE) as the physical cause for the accelerated expansion of the Universe is the most remarkable experimental finding of modern cosmology. However, it leads to insurmountable theoretical difficulties from the…
We investigate the gravitational production of scalar dark matter particles during the inflationary and reheating epochs. The oscillatory behavior of the curvature scalar $R$ during the reheating phase generates two different enhancement…
The physics of de Sitter space is essential to our understanding of our cosmological past, present, and future. It forms the foundation for the statistical predictions of inflation in terms of quantum vacuum fluctuations that are being…
We review the particle theory origin of inflation and curvaton mechanisms for generating large scale structures and the observed temperature anisotropy in the cosmic microwave background (CMB) radiation. Since inflaton or curvaton energy…
In the present model, a unified picture of cosmology from early inflation to late acceleration is obtained from $ f(R)-$ gravity with non-linear terms $ R^2 $ and $ R^5 $ of scalar curvature $R$. It is discussed that elementary particles…
We investigate non-perturbative production of fermionic dark matter in the early universe. We study analytically the gravitational production mechanism accompanied by the coupling of fermions to the background inflaton field. The latter…
We investigate the production of non-thermal fermionic dark matter particles during the reheating era following slow roll inflation, driven by inflaton $\varphi$ non-minimally coupled to the curvature scalar, $\mathcal{R}$. Two types of…
We summarize three recent efforts to constrain the first few moments of cosmic creation before and during the epoch of inflation. We consider two means to explain a slight dip in the power spectrum of the cosmic microwave background for…
We have investigated cosmological models with a self-interacting scalar field and a dissipative matter fluid as the sources of matter. Different variables are expressed in terms of a {\it generating function}. Exact solutions are obtained…
We review conceptual aspects of inflationary scenarios able to produce primordial black holes, by amplifying the size of curvature fluctuations to the level required for triggering black hole formation. We identify general mechanisms to do…
We explore a mechanism to produce a light dark photon dark matter through a coupling between the dark photon field and a spectator scalar field which plays no role in the inflationary expansion of the Universe while rolling down its…
During inflation, the geometry of spacetime is described by a (quasi-)de Sitter phase. Inflationary observables are determined by the underlying (softly broken) de Sitter isometry group SO(1, 4) which acts like a conformal group on R^3:…
We explore the observational consequences of resonant particle production during inflation, focusing on its impact on dark matter annihilation signals today. A transient burst of particle production generates localised features in the…
The generation of large curvature perturbations associated with the production of primordial black holes is studied in the context of a Higgs inflaton. To enable this amplification, we consider an inflationary model in which the tree-level…
We develop a theory of dark matter based on a previously proposed picture, in which a complex vacuum scalar field makes the universe a superfluid, with the energy density of the superfluid giving rise to dark energy, and variations from…
We present a minimal UV complete framework to embed inflation and dark matter by extending the standard model with a singlet real scalar field (the inflaton) and a singlet fermonic field acting as dark matter. The inflaton features the most…