相关论文: Age problem in holographic dark energy

Because of an old quasar APM 08279+5255 at $z=3.91$, some dark energy models face the challenge of the cosmic age problem. It has been shown by Wei and Zhang [Phys. Rev. D {\bf 76}, 063003 (2007)] that the holographic dark energy model is…

The discovery of the quasar, the APM 08279+5255 at z = 3.91 whose age is 2-3 Gyr has once again led to ``age crisis''. The noticeable fact about this object is that it cannot be accommodated in a universe with $\Omega_m = 0.27$, currently…

Many dark energy models fail to pass the cosmic age test because of the old quasar APM 08279+5255 at redshift $z=3.91$, the $\Lambda$CDM model and holographic dark energy models being no exception. In this paper, we focus on the topic of…

We investigate the cosmic age problem associated with the old high-$z$ quasar APM 08279 + 5255 and the oldest globular cluster M 107, both being difficult to accommodate in $\Lambda$CDM model. By evaluating the age of the Universe in a…

We investigate the age constraint on the agegraphic dark energy model by using two old galaxies (LBDS 53W091 and LBDS 53W069) and the old high redshift quasar APM 08279+5255. We find that the agegraphic dark energy model can easily…

In this note, we test the original holographic dark energy model with some old high redshift objects. The main idea is very simple: the universe cannot be younger than its constituents. We find that the original holographic dark energy…

We investigate the cosmic age problem associated with 9 extremely old globular clusters in M31 galaxy and 1 very old high-$z$ quasar APM 08279 + 5255 at $z=3.91$. These 9 globular clusters have not been used to study the cosmic age problem…

The existence of old high-redshift objects provides an important tool for constraining the expanding age of the Universe and the formation epoch of the first objects. In a recent paper, Hasinger {\it et al.} (2002) reported the discovery of…

Dark energy is the invisible fuel that seems to drive the current acceleration of the Universe. Its presence, which is inferred from an impressive convergence of high-quality observational results along with some apparently sucessful…

Many dark energy models fail to pass the cosmic age test. In this paper, we investigate the cosmic age problem associated with nine extremely old Global Clusters (GCs) and the old quasar APM $08279+5255$ in the $R_h=ct$ Universe. The age…

We investigate some observational constraints on decaying vacuum cosmologies based on the recently discovered old high redshift quasar APM 08279+5255. This object is located at $z = 3.91$ and has an estimated age of 2-3 Gyr. The class of…

We investigate the viscous Ricci dark energy (RDE) model by assuming that there is bulk viscosity in the linear barotropic fluid and the RDE. In the RDE model without bulk viscosity, the universe is younger than some old objects at some…

We constrain an interacting, holographic dark energy model, first proposed by two of us in [1], with observational data from supernovae, CMB shift, baryon acoustic oscillations, x-rays, and the Hubble rate. The growth function for this…

The age problem in the $\Lambda$CDM model is re-examined. We define the elapsed time $T$ of an object is its age plus the age of the Universe when it was born. Therefore in any cosmology, $T$ must be smaller than the age of the Universe.…

We introduce a holographic dark energy model that incorporates the first-order approximate Kaniadaski entropy, utilizing the Hubble horizon, $1/H$, as the infrared cutoff. We investigate the cosmological evolution within this framework. The…

Using the absolute ages of passively evolving galaxies observed at different redshifts, one can obtain the differential ages, the derivative of redshift $z$ with respect to the cosmic time $t$ (i.e. ${\rm d} z/{\rm d}t$). Thus, the Hubble…

Several observational constraints are imposed on the interacting holographic model of Dark Energy and Dark Matter. First we use the age parameter today, as given by the WMAP results. Subsequently, we explained the reason why it is possible,…

The viability of two different classes of $\Lambda(t)$CDM cosmologies is tested by using the APM 08279+5255, an old quasar at redshift $z = 3.91$. In the first class of models, the cosmological term scales as $\Lambda(t)\sim R^{-n}$. The…

In this paper, we analyze the agegraphic dark energy from the entropy of the anti-de Sitter black hole using the age of the universe as the IR cutoff. We constrain its parameter with the Pantheon+ Type Ia supernova sample and observational…

In this letter we consider a dark energy model in which the energy density is a function of the Hubble parameter $H$ and its derivative with respect to time $\rho_{de}=3\alpha \ddot{H}H^{-1}+3\beta\dot{H}+3\gamma H^2$. The behavior of the…