Related papers: Nonstandard cosmologies from physics beyond the St…
This is a course on cosmic microwave background (CMB) anisotropies in the standard cosmological model, designed for beginning graduate students and advanced undergraduates. ``Standard cosmological model'' in this context means a Universe…
We construct a new non-singular cosmological model matched to a Minkowski-core regular black hole by means of a modified Oppenheimer--Snyder framework. Its dynamics is studied in both dust-only and scalar-field scenarios, and compared with…
The Standard Cosmological Model of the 1980's is no more. I describe the definitive evidence that the density of matter is insufficient to result in a flat universe, as well as the mounting evidence that the cosmological constant is not…
Over the last decades, observations with increasing quality have revolutionized our understanding of the general properties of the Universe. Questions posed for millenia by mankind about the origin, evolution and structure of the cosmos…
The absence of guidance from fundamental physics about the mechanism behind cosmic acceleration has given rise to a number of alternative cosmological scenarios. These are based either on modifications of general relativistic gravitation…
An extension of the Standard Model by extra scalar singlets was considered. Theoretical (unitarity, vacuum stability, triviality) and cosmological (dark matter relic abundance, direct detection experiments, constraints on dark matter…
Cosmology is intrinsically intertwined with questions in fundamental physics. The existence of non-baryonic dark matter requires new physics beyond the Standard Model of elemenatary-particle interactions and Einstein's general relativity,…
The problem of reproducing dark energy effects is reviewed here with particular interest devoted to cosmography. We summarize some of the most relevant cosmological models, based on the assumption that the corresponding barotropic equations…
A non-commutative multi-dimensional cosmological model is introduced and used to address the issues of compactification and stabilization of extra dimensions and the cosmological constant problem. We show that in such a scenario these…
I will review some results of observational cosmology which critically cast doubt upon the foundations of the standard cosmology: 1) The redshifts of the galaxies are due to the expansion of the Universe; 2) The cosmic microwave background…
Cosmography can be considered as a sort of a model-independent approach to tackle the dark energy/modified gravity problem. In this review, the success and the shortcomings of the $\Lambda$CDM model, based on General Relativity and standard…
A range of cosmological observations demonstrate an accelerated expansion of the Universe, and the most likely explanation of this phenomenon is a cosmological constant. Given the importance of understanding the underlying physics, it is…
The standard cosmological model, based on general relativity with an inflationary era, is very effective in accounting for a broad range of observed features of the universe. However, the ongoing puzzles about the nature of dark matter and…
This paper deals with the cancellation mechanism, which identifies the energy density of space-time expansion in an empty universe with the zero-point energy density and avoids the scale discrepancy with the observed energy density…
Alternative cosmological models have been under deep scrutiny in recent years, aiming to address the main shortcomings of the $\Lambda$CDM model. Moreover, as the accuracy of cosmological surveys improved, new tensions have risen between…
The late time acceleration of the Universe has challenged contemporary cosmology since its discovery. General Relativity explains this phenomenon by introducing the cosmological constant, named the standard cosmological model…
We perform a cosmographic analysis using several cosmological observables such as the luminosity distance moduli, the volume distance, the angular diameter distance and the Hubble parameter. These quantities are determined using different…
Cosmological models often contain scalar fields, which can acquire global nonzero expectation values that change with the comoving time. Among the possible consequences of these scalar-field backgrounds, an accelerated cosmological…
We look for cosmologies with a scalar field (dark energy without cosmological constant), which mimic the standard $\Lambda CDM$ cosmological model yielding exactly the same large-scale geometry described by the evolution of the Hubble…
Interactions inside the cosmological dark sector influence the cosmological dynamics. As a consequence, the future evolution of the Universe may be different from that predicted by the $\Lambda$CDM model. We review main features of several…