Related papers: Geometrical constraints on dark energy models
While the LCDM framework has been incredibly successful for modern cosmology, it requires the admission of two mysterious substances as a part of the paradigm, dark energy and dark matter. Although this framework adequately explains most of…
We examine the dark energy and matter densities allowed by precision measurements of distances out to various redshifts, in the presence of spatial curvature and (near) arbitrary behavior of the dark energy equation of state. Degeneracies…
The cosmological constant, which was introduced by Einstein a century ago to allow for a static universe, experienced a revival two decades ago under the label dark energy as a parameter to model the observed accelerated expansion of the…
The last decade has shown a considerable development of gravitational lensing for cosmology because it probes the amount and the nature of dark matter, and provides information on the density parameter $\Omega$, the cosmological constant…
This is a brief sketch of the use of supernovae to measure cosmological parameters. It traces the early work, the events surrounding the discovery and verification of cosmic acceleration using SN Ia, and the efforts today to make sound…
Cosmological observations offer unique and robust avenues for probing the fundamental nature of dark matter particles-they broadly test a range of compelling theoretical scenarios, often surpassing or complementing the reach of terrestrial…
A phenomenological approach is proposed to the problem of universe accelerated expansion and of the dark energy nature. A general class of models is introduced whose energy density depends on the redshift $z$ in such a way that a smooth…
This talk presents a pedagogical discussion of how precision distance-redshift observations can map out the recent expansion history of the universe, including the present acceleration and the transition to matter dominated deceleration.…
In these lectures we first concentrate on the cosmological problems which, hopefully, have to do with the new physics to be probed at the LHC: the nature and origin of dark matter and generation of matter-antimatter asymmetry. We give…
Observations conducted over the last few decades show that the expansion of the Universe is accelerating. In the standard model of cosmology, this accelerated expansion is attributed to a dark energy in the form of a cosmological constant.…
It has been recently proposed that gravity might be an entropic force. Although a well defined fundamental description for such a mechanism is still lacking, it is still possible to address the viability of phenomenological models of…
In modern cosmology, the discovery of the universe's accelerated expansion has significantly transformed our understanding of cosmic evolution and expansion history. The unknown properties of dark energy, the driver of this acceleration,…
Recent cosmological observations suggest that nearly seventy per cent of the energy density in the universe is unclustered and has negative pressure. Several conceptual issues related to the modeling of this component (`dark energy'), which…
We discuss combined constraints, coming from the cosmic microwave background shift parameter $\mathcal{R}$, baryon acoustic oscillations (BAO) distance parameter $\mathcal{A}$, and from the latest type Ia supernovae data, imposed on…
Physics invites the idea that space contains energy whose gravitational effect approximates that of Einstein's cosmological constant, Lambda; nowadays the concept is termed dark energy or quintessence. Physics also suggests the dark energy…
The cosmological constant and many other possible origins for acceleration of the cosmic expansion possess variations in the dark energy properties slow on the Hubble time scale. Given that models with more rapid variation, or even phase…
We propose a cosmological model that makes a significant step toward solving the coincidence problem of the near similarity at the present of the dark energy and dark matter components. Our cosmology has the following properties: a) among…
Given a class of dark energy models, constraints from one set of cosmic acceleration observables make predictions for other observables. Here we present the allowed ranges for the expansion rate H(z), distances D(z), and the linear growth…
The cosmic acceleration is one of the most significant cosmological discoveries over the last century. The two categories of explanation are exotic component (dark energy) and modified gravity. We constrain the two types of model by a joint…
We find that current Cosmic Microwave Background (CMB) anisotropy data strongly constrain the mean spatial curvature of the Universe to be near zero, or, equivalently, the total energy density to be near critical-as predicted by inflation.…