Related papers: Can we avoid dark energy?
We apply the Union2 compilation of 557 supernova Ia data, the baryon acoustic oscillation measurement of distance, the cosmic microwave background radiation data from the seven year Wilkinson Microwave Anisotropy Probe, and the Hubble…
We consider the generic scenario of dark energy which arises through the latent heat of a hidden sector first order cosmological phase transition. This field could account for the extra radiation degree of freedom suggested by the CMB. We…
The coupling between the dark components provides a new approach to mitigate the coincidence problem of cosmological standard model. In this paper, dark energy is treated as a fluid with a constant equation of state, whose coupling with…
The current Universe is composed by a mixture of relativistic species, baryonic matter, dark matter and dark energy which evolve in a non-trivial way at perturbative level. An advanced description of the cosmological dynamics should include…
The luminosity distance vs. redshift law is now measured using supernovae and gamma ray bursts, and the angular size distance is measured at the surface of last scattering by the CMB and at z = 0.35 by baryon acoustic oscillations. In this…
We investigate the consequences of a non-negligible baryon fraction for models of structure formation in Cold Dark Matter dominated cosmologies, emphasizing in particular the existence of oscillations in the present-day matter power…
The latest results on baryon acoustic oscillations from DESI (Dark Energy Spectroscopic Instrument), when combined with cosmic microwave background and supernova data, show indications of a deviation from a cosmological constant in favour…
We present strong evidence for dynamical dark energy that challenges the standard $\Lambda$CDM model. Several dark energy scenarios are explored, including $\omega_0\omega_a$CDM, logarithmic, exponential, JBP, and BA parameterizations,…
We discuss what can be learned about the baryon density from an all-sky map of the cosmic microwave background (CMB) with sub-degree angular resolution. With only minimal assumptions about the primordial spectrum of density perturbations…
The dark sector of the Universe need not be completely separable into distinct dark matter and dark energy components. We consider a model of early dark energy in which the dark energy mimics a dark matter component in both evolution and…
We show that current cosmic acceleration can be explained by an almost massless scalar field experiencing quantum fluctuations during primordial inflation. Provided its mass does not exceed the Hubble parameter today, this field has been…
For the first time, we have a plausible and complete accounting of matter and energy in the Universe. Expressed a fraction of the critical density it goes like this: neutrinos, between 0.3% and 15%; stars, between 0.3% and 0.6%; baryons…
We investigate the viability of a cosmological scenario with interacting dark sector, which can describe the coexistence between dark energy and dark matter. The model possesses an analytical solution for the Hubble function and we…
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…
We investigate a specific emergent dark energy scenario, known as critically emergent dark energy (CEDE), in which dark energy is effectively absent in the early Universe and becomes dynamically relevant only after a critical cosmic epoch…
Some form of missing energy may account for the difference between the observed cosmic matter density and the critical density. Two leading candidates are a cosmological constant and quintessence (a time-varying, inhomogenous component with…
Unless some unknown symmetry in Nature prevents or suppresses a non-minimal coupling in the dark sector, the dark energy field may interact with the pressureless component of dark matter. In this paper, we investigate some cosmological…
In this work we perform some studies related to dark energy. Firstly, we propose a dynamical approach to explain the dark energy content of the universe. We assume that a massless scalar field couples to the Hubble parameter with some…
The characterisation of dark energy is one of the primary goals in cosmology especially now that many new experiments are being planned with the aim of reaching a high sensitivity on cosmological parameters. It is known that if we move away…
We use baryon acoustic peak measurements by Eisenstein et al. (2005) and Percival et al. (2007a) and galaxy cluster gas mass fraction measurements of Allen et al. (2008) to constrain parameters of three different dark energy models. For…