Related papers: Quintessence Model and Cosmic Microwave Background
The cosmological term, $\Lambda$, in Einstein's equations is an essential ingredient of the `concordance' $\Lambda$CDM model of cosmology. In this mini-review presentation, we assess the possibility that $\Lambda$ can be a dynamical…
The idea that the vacuum energy density $\rho_{\Lambda}$ could be time dependent is a most reasonable one in the expanding Universe; in fact, much more reasonable than just a rigid cosmological constant for the entire cosmic history. Being…
The quantum mechanics description of a physical object stretched in space and stable in time from the relativistic space-time properties point of view, introduced in special theory of relativity, is considered and analysed. The mathematical…
In cosmology, phenomenologically motivated expressions for running vacuum are commonly parametrized as linear functions $\Lambda(H^2)$ or $\Lambda(R)$. Such kind of models assume an equation of state for vacuum given by $\,\overline…
We have studied the closed universe model with the variable cosmological term, which is presented as a sum of two terms: Lambda=Lambda_0 -k R. First term Lambda_0 is a constant and it is describing a sum of quantum field's zero…
We consider the efficacy of using luminosity distance measurements of deep redshift supernovae to discriminate between two forms of dark energy, quintessence (a scalar field with canonical kinetic terms rolling down a potential) and…
We discussed the dynamics of cosmological models in which the cosmological constant term is a time dependent function through the scale factor $a(t)$, Hubble function $H(t)$, Ricci scalar $R(t)$ and scalar field $\phi(t)$. We considered…
The Einstein-Klein-Gordon field equations are solved in a inhomogeneous shear-free universe containing a material fluid, a self-interacting scalar field, a variable cosmological term, and a heat flux. A quintessence-dominated scenario…
A cosmological model with modification of the Einstein-Hilbert action by the correction $f(R)\propto \beta R^n$ is considered. Such way of the description of the ``geometrical'' dark energy has been introduced repeatedly and the…
Calculating molecular properties using quantum devices can be done through the quantum linear response (qLR) or, equivalently, the quantum equation of motion (qEOM) formulations. Different parameterizations of qLR and qEOM are available,…
We consider a cosmology with decaying metastable dark energy and assume that a decay process of this metastable dark energy is a quantum decay process. Such an assumption implies among others that the evolution of the Universe is…
Some of the arguments which support the strong concensus for an $\Omega_o$ = 0.3, $\lambda_o$ = 0.7 model are reexamined. Corrections for Malmquist bias, local flow and metallicity suggest a revised value for $H_o$ of 63 $\pm$ 6 km/s/Mpc,…
The $m$-$z$ relation for type Ia supernovae is one of the key pieces of evidence supporting the cosmological `concordance model' with $\lambda_0 \approx 0.7$ and $\Omega_0 \approx 0.3$. However, it is well known that the $m$-$z$ relation…
The equivalence postulate approach to quantum mechanics entails a derivation of quantum mechanics from a fundamental geometrical principle. Underlying the formalism there exists a basic cocycle condition, which is invariant under…
The concordance model of cosmology contains several unknown components such as dark matter and dark energy. Many proposals have been made to describe them by choosing an appropriate potential for a scalar field. We study four models in the…
The fundamental constants of electromagnetism, gravity and quantum mechanics can be related empirically by the numerical approximation $\ln(V_e/V_P)\approx \alpha^{-1}$, where $\alpha$ is the low energy value of the electromagnetic fine…
We study a class of braneworlds where the cosmological evolution arises as the result of the movement of a three-brane in a five-dimensional static dilatonic bulk, with and without reflection symmetry. The resulting four-dimensional…
The distance-redshift relation depends on the amount of matter of each type in the universe. Measurements at different redshifts constrain differing combinations of these matter densities and thus may be used in combination to constrain…
A scale-dependent cosmology is proposed in which the Robertson-Walker metric and the Einstein equation are modified in such a way that $\Omega_0$, $H_0$ and the age of the Universe all become scale-dependent. Its implications on the…
We explore regions of parameter space in a simple exponential model of the form $V = V_0 e^{- \lambda \frac{Q}{M_p}}$ that are allowed by observational constraints. We find that the level of fine tuning in these models is not different from…