Related papers: Testing Dark Energy and Cardassian Expansion for C…
Non-negligible dark energy density at high redshifts would indicate dark energy physics distinct from a cosmological constant or ``reasonable'' canonical scalar fields. Such dark energy can be constrained tightly through investigation of…
We study a dark energy scenario in the presence of a tachyon field $\phi$ with potential $V(\phi)$ and a barotropic perfect fluid. The cosmological dynamics crucially depends on the asymptotic behavior of the quantity…
I review the linear and second-order perturbation theory in dark energy models with explicit interaction to matter in view of applications to N-body simulations and non-linear phenomena. Several new or generalized results are obtained: the…
A web of interlocking observations has established that the expansion of the Universe is speeding up and not slowing, revealing the presence of some form of repulsive gravity. Within the context of general relativity the cause of cosmic…
We suggest that the current acceleration of the universe may be explained by the vacuum energy of a hidden sector which is stuck in a state of equilibrium between phases. The phases are associated to a late-time first-order phase…
Deep Learning models have shown success in a large variety of tasks by extracting correlation patterns from high-dimensional data but still struggle when generalizing out of their initial distribution. As causal engines aim to learn…
The principle called information causality has been used to deduce Tsirelson's bound. In this paper we derive information causality from monotonicity of divergence and relate it to more basic principles related to measurements on…
The evolution of the dark energy parameter within the scope of a spatially homogeneous and isotropic Friedmann-Robertson-Walker (FRW) model filled with perfect fluid and dark energy components is studied by generalizing the recent results…
An oscillating scalar field as a quintessence model for dark energy is proposed. The case of a power-law potential is particularly intriguing and is the focus of the present article. In this model the equation of state w_{OQ} of dark energy…
A set of cosmological models that takes into account the variation of the particle number is presented. In this context both dark matter and dark energy can be explained using a single component, without assuming any exotic equation of…
We study the phase space dynamics of the non-minimally coupled Metric-Scalar-Torsion model in both Jordan and Einstein frames. We specifically check for the existence of critical points which yield stable solutions representing the current…
A finite vacuum energy density implies the existence of a UV scale for gravitational modes. This gives a phenomenological scale to the dynamical equations governing the cosmological expansion that must satisfy constraints consistent with…
The recent discovery of apparent cosmic acceleration has highlighted the depth of our ignorance of the fundamental properties of nature. It is commonly assumed that the explanation for acceleration must come from a new form of energy…
ecent observations of type Ia supernovae indicate that the Universe is in an accelerating phase of expansion. The fundamental quest in theoretical cosmology is to identify the origin of this phenomenon. In principle there are two…
Recently, we give the robust $\sim2\,\sigma$ evidences of dynamical dark matter and beyond $2\,\sigma$ signals of the coexistence of dynamical dark matter and dynamical dark energy using current cosmological observations [1]. Here we…
Velocity-dependent interactions in a fundamental-string dominated universe lead quite naturally, with reasonable assumptions on initial conditions, to an accelerating expanding universe without assuming the existence of a cosmological…
We investigate several varying-mass dark-matter particle models in the framework of phantom cosmology. We examine whether there exist late-time cosmological solutions, corresponding to an accelerating universe and possessing dark energy and…
We develop rigorous notions of causality and causal separability in the process framework introduced in [Oreshkov, Costa, Brukner, Nat. Commun. 3, 1092 (2012)], which describes correlations between separate local experiments without a prior…
Here, cosmology of the late and future universe is obtained from $f(R)$-gravity with non-linear curvature terms $R^2$ and $R^3$ ($R$ being the Ricci scalar curvature). It is different from $f(R)$-dark enrgy models, where non-linear…
A new degravitation mechanism within the framework of scalar tensor gravity is postulated and included by prescription. The mechanism eliminates all constant contributions from the potential to the Friedmann equation, leaving only the…