Related papers: Scalar Field Dark Energy Parametrization
Within the framework of spatially covariant theories, we propose a general model for dark energy (DE) in which the cosmological background and perturbations are independently controlled by different sets of coefficients, and the equation of…
Beyond the standard cosmological model the late-time accelerated expansion of the universe can be reproduced by the introduction of an additional dynamical scalar field. In this case, the field is expected to be naturally coupled to the…
A so called "power-law entropy-corrected holographic dark energy" (PLECHDE) was recently proposed to explain the dark energy dominated universe. This model is based on the power-law corrections to black hole entropy which appear in dealing…
We discuss the possibility of a scalar field being the fundamental description of dark energy. We focus on shift-symmetric scalar-tensor theories since this symmetry potentially avoids some fine-tuning problems. We also restrict attention…
Dark Energy models with slowly-rolling cosmological scalar field provide a popular alternative to the standard, time-independent cosmological constant model. We study simultaneous evolution of background expansion and growth in the scalar…
Dark Energy is some of the weirdest and most mysterious stuff in the universe that tends to increase the rate of expansion of the universe. Two commonly known forms of dark energy are the cosmological constant, a constant energy density…
Since the discovery of the accelerated expansion of the Universe, the constraints on the equation of state $w_\text{DE}$ of dark energy, the stress-energy component responsible for the acceleration, have tightened significantly. These…
The current paper provides a comprehensive examination of a dark energy cosmological model in the classical regime, in which a generic scalar field is regarded as a dark energy source. Einstein's field equations are solved in model…
We investigate cosmological models in which dynamical dark energy consists of a scalar field whose present-day value is controlled by a coupling to the neutrino sector. The behaviour of the scalar field depends on three functions: a kinetic…
In this paper we investigate the accelerating and decelerating cosmological models with non-linear spinor fields and non-minimal interaction of $f(R)$ gravity with a scalar field. We combine two different approaches to the description of…
High precision cosmological observations in last decade suggest that about 70% of our universe's energy density is in so called "Dark Energy" (DE). Observations show that DE has negative effective pressure and therefore unlike conventional…
We have calculated constraints on the evolution of the equation of state of the dark energy, w(z), from a joint analysis of data from the cosmic microwave background, large scale structure and type-Ia supernovae. In order to probe the…
We consider the cosmological application of Lee-Wick theory where a field has a higher derivative kinetic operators. The higher derivative term can be eliminated by introducing a set of auxiliary fields. We investigate the cosmological…
We propose a dark energy model with a logarithmic cosmological fluid which can result in a very small current value of the dark energy density and avoid the coincidence problem without much fine-tuning. We construct a couple of dynamical…
In this work we examine the 2025 DESI analysis of dark energy, which suggests that dark energy is evolving in time with an increasing equation of state $w$. We explore a wide range of quintessence models, described by a potential function…
We study static configurations of dark matter coupled to a scalar field responsible for the dark energy of the Universe. The dark matter is modelled as a Fermi gas within the Thomas-Fermi approximation. The mass of the dark matter particles…
In this paper, we have considered various dark energy models in the framework of a non-canonical scalar field with a Lagrangian density of the form ${\cal L}(\phi, X)=f(\phi)X{\left(\frac{X}{M^{4}_{Pl}}\right)}^{\alpha -1} - V(\phi)$, which…
Theories of evolving quintessence are constructed that generically lead to deviations from the w = -1 prediction of non-evolving dark energy. The small mass scale that governs evolution, m_\phi \approx 10^{-33} eV, is radiatively stable,…
We use action-angle variables to describe the basic physics of coherent scalar field oscillations in the expanding universe. These analytical mechanics methods have some advantages, like the identification of adiabatic invariants. As an…
Important observables to reveal the nature of dark energy are the equation of state $w$ and its time derivative in units of the Hubble time $w'$. Recently, it is shown that the simplest scalar field models of dark energy (quintessence)…