相关论文: No Evidence for Dark Energy Evolution from a globa…
The cause of the accelerated expansion of the Universe poses one of the most fundamental questions in physics today. In the absence of a compelling theory to explain the observations, a first task is to develop a robust phenomenology. If…
The dark energy component of the universe is often interpreted either in terms of a cosmological constant or as a scalar field. A generic feature of the scalar field models is that the equation of state parameter w= P/rho for the dark…
The formalism in order to obtain the Dark Energy equation of state is extended to non-flat universes and we consider the inequalities that must be satisfied by Phantom Dark Energy in this case. We show that due to a non-vanishing spatial…
We study how observationally to distinguish between a cosmological constant (CC) and an evolving dark energy with equation of state $\omega(Z)$. We focus on the value of redshift Z* at which the cosmic late time acceleration begins and…
We explore various pitfalls and challenges in determining the equation-of-state (w) of dark energy component that dominates the universe and causes the current accelerated expansion. We demonstrated in an earlier paper the existence of a…
Hubble constant tension, together with the recent indications of dynamical dark energy proposed from the Dark Energy Spectroscopic Instrument (DESI) baryon acoustic oscillation (BAO) measurements, poses significant challenges to the…
In this paper, observational constraints on the cosmic equation of state of dark energy ($p = w \rho$) have been investigated using gravitational lensing statistics. A likelihood analysis of the lens surveys has been carried out to…
We reconstruct evolution of the dark energy (DE) density using a nonparametric Bayesian approach from a combination of latest observational data. We caution against parameterizing DE in terms of its equation of state as it can be singular…
Our universe is observed to be accelerating due to the dominant dark energy with negative pressure. The dark energy equation of state (w) holds a key to understanding the ultimate fate of the universe. The cosmic voids behave like bubbles…
We study the dark energy equation of state as a function of redshift in a non-parametric way, without imposing any {\it a priori} $w(z)$ (ratio of pressure over energy density) functional form. As a check of the method, we test our scheme…
The explanation of the accelerated expansion of the Universe poses one of the most fundamental questions in physics and cosmology today. If the acceleration is driven by some form of dark energy, one can try to constrain the parameters…
One of the most compelling goals of observational cosmology is the characterisation of the properties of the dark energy component thought to be responsible for the recent acceleration of the universe, including its possible dynamics. In…
Dark energy is one of the mysteries of modern science. It is unlike any known form of matter or energy and has been detected so far only by its gravitational effect of repulsion. Owing to its effects being discernible only at very very…
This study explores the possibility of a time-varying dark energy (DE) equation of state (EoS) deviating from -1. We employ a comprehensive dataset of usual astronomical probes (Type Ia supernovae, baryon acoustic oscillations, Big Bang…
Observational evidence indicating that the expansion of the universe is accelerating has surprised cosmologists in recent years. Cosmological models have sought to explain this acceleration by incorporating `dark energy', of which the…
Current constraints on the dark energy equation of state parameter, $w$, are expected to be improved by more than one order of magnitude in the next decade. If $|w-1| \gsim 0.01$ around the present time, but the dark energy dynamics is…
An important issue in cosmology is reconstructing the effective dark energy equation of state directly from observations. With so few physically motivated models, future dark energy studies cannot only be based on constraining a dark energy…
We investigate a brane model based on Randall-Sundrum scenarios with a generic dark energy component. The latter drives the accelerated expansion at late times of the Universe. In this scheme, extra terms are added into Einstein Field…
We compare the maximal abundance of massive systems predicted in different dynamical dark energy (DDE) models at high redshifts z = 4-7 with the measured abundance of the most massive galaxies observed to be already in place at such…
We point out that the CPL parametrization has a problem that the equation of state $w(z)$ diverges in the far future, so that this model can only properly describe the past evolution but cannot depict the future evolution. To overcome such…