Related papers: Future Dark Energy Constraints from Atomic Clocks
To explore whether there is new physics going beyond the standard cosmological model or not, we constrain seven cosmological models by combining the latest and largest Pantheon Type Ia supernovae sample with the data combination of baryonic…
We use the latest compilation of observational Hubble parameter measurements estimated with the differential evolution of cosmic chronometers, in combination with the local value of the Hubble constant recently measured with 2.4% precision,…
The possibility of constraining the parameters of scalar field dark energy with barotropic equation of state using different available datasets is discussed. It has been found that the initial value of dark energy equation of state…
We compute the Bayesian evidences for one- and two-parameter models of evolving dark energy, and compare them to the evidence for a cosmological constant, using current data from Type Ia supernova, baryon acoustic oscillations, and the…
In this paper, we present a unified scheme based on the fluid description of the dark sector of the universe. The scheme captures models with interaction between dark energy and dark matter, being the core of generalization the time-varying…
All clocks, classical or quantum, are open non equilibrium irreversible systems subject to the constraints of thermodynamics. Using examples I show that these constraints necessarily limit the performance of clocks and that good clocks…
Dark matter and dark energy are usually assumed to couple only gravitationally. An extension to this picture is to model dark energy as a scalar field coupled directly to cold dark matter. This coupling leads to new physical effects, such…
A huge amount of good quality astrophysical data converges towards the picture of a spatially flat universe undergoing the today observed phase of accelerated expansion. This new observational trend is commonly addressed as Precision…
We investigate constraints on dark energy fluctuations using type Ia supernovae. If dark energy is not in the form of a cosmological constant, that is if the equation of state is not equal to -1, we expect not only temporal, but also…
The high-quality cosmological data, which became available in the last decade, have thrusted upon us a rather preposterous composition for the universe which poses one of the greatest challenges theoretical physics has ever faced: the…
The late time acceleration of the Universe can be characterized in terms of an extra, time dependent, component of the universe -- dark energy. The simplest proposal for dark energy is a scalar-tensor theory -- quintessence -- which…
We combine complementary datasets to constrain dark energy. Using standard Big Bang Nucleosynthesis and the observed abundances of primordial nuclides to put constraints on $\Omega_Q$ at temperatures near $T \sim 1MeV$, we find the strong…
The accelerated expansion of the Universe is one of the main discoveries of the past decades, indicating the presence of an unknown component: the dark energy. Evidence of its presence is being gathered by a succession of observational…
Theories with a time dependent Newton's constant admit two natural measures of time : atomic and astronomical. Temporal parametrisation by SL(2, R) transformations gives rise to an equivalence between theories with different time…
Active atomic clocks are predicted to provide far better short-term stability and robustness against thermal fluctuations than typical feedback-based optical atomic clocks. However, continuous laser operation using an ensemble of clock…
Recent developments in frequency metrology and optical clocks have been based on electronic transitions in atoms and singly charged ions as references. These systems have enabled relative frequency uncertainties at a level of a few parts in…
Dark energy models which alter the relative scaling behavior of dark energy and matter could provide a natural solution to the cosmic coincidence problem - why the densities of dark energy and dark matter are comparable today. A generalized…
The paper studies a new type of dark energy, a scalar field with positive or negative kinetic energy, generically coupled to a term which is composed by specific contractions of the Riemann tensor. After presenting the resulting field…
Major observational efforts in the coming decade are designed to probe the equation of state of dark energy. Measuring a deviation of the equation-of-state parameter w from -1 would indicate a dark energy that cannot be represented solely…
Most dark energy models have the $\Lambda$CDM as their limit, and if future observations constrain our universe to be close to $\Lambda$CDM Bayesian arguments about the evidence and the fine-tuning will have to be employed to discriminate…