相关论文: Early dark energy in $k$-essence

Most of the models leading to a current state of cosmic accelerated expansion fail to address the coincidence problem, i.e., that the dark energy density and the energy density of the matter fluid are of the same order precisely today. We…

We investigate the observational consequences of a novel class of stable interacting dark energy (IDE) models, featuring interactions between dark matter (DM) and dark energy (DE). In the first part of our work, we start by considering two…

Sign-switching dark energy provides a novel mechanism for modifying the late-time expansion history of the Universe without invoking additional fields or finely tuned initial conditions. In this work, we investigate a class of…

We explore quintessence models of dark energy which exhibit non-minimal coupling between the dark matter and the dark energy components of the cosmic fluid. The kind of coupling chosen is inspired in scalar-tensor theories of gravity. We…

If dark matter resides in a hidden sector minimally coupled to the Standard Model, another particle within the hidden sector might dominate the energy density of the early universe temporarily, causing an early matter-dominated era (EMDE).…

The $\Lambda$CDM model has successfully explained a wide range of cosmological observations, but is increasingly challenged by the emergence of cosmological tensions, particularly the Hubble Tension $H_0$ and the $S_8$ tension. The Hubble…

In this paper we fit two models of Early Dark Energy (EDE) (an increase in the expansion rate before recombination) to the combination of Atacama Cosmology Telescope (ACT) measurements of the Cosmic Microwave Background (CMB) with data from…

The enigmatic phenomenon of dark energy (DE) is regarded as the elusive entity driving the accelerated expansion of our Universe. A plausible candidate for DE is the non-zero Einstein Cosmological Constant $\Lambda_{E}$ manifested as a…

In this work, we study a class of early dark energy (EDE) models, in which, unlike in standard DE models, a substantial amount of DE exists in the matter-dominated era, self-consistently including DE perturbations. Our analysis shows that,…

An interacting dark energy model with interaction term $Q= \lambda_m H\rho_m+\lambda_dH\rho_d$ is considered. By studying the model near the transition time, in which the system crosses the w=-1 phantom-divide-line, the conditions needed to…

In the effort to define the main features a successful solution to the Hubble tension should have, growing evidence has emerged pointing to the need for models able to modify the expansion (and possibly thermal) history of the universe both…

We consider cosmological models in which Dark Matter (DM) and Dark Energy (DE) are described by a single component, dubbed Unified Dark Matter (UDM) models, in which the DE-like part can have an equation state $<-1$ at late times without…

We forecast the expected cosmological constraints from a combination of probes of both the universal expansion rate and matter perturbation growth, in the form of weak lensing tomography, galaxy tomography, supernovae, and the cosmic…

Early dark energy solutions to the Hubble tension introduce an additional scalar field which is frozen at early times but becomes dynamical around matter-radiation equality. In order to alleviate the tension, the scalar's share of the total…

Axion-like scalar fields can induce temporary deviations from the standard expansion history of the universe. The scalar field's contribution to the energy density of the universe grows while the field is held constant by Hubble friction,…

We evaluate the effectiveness of Early Dark Energy (EDE) in addressing the Hubble tension using data from the completed eBOSS survey, focusing on luminous red galaxies (LRGs), quasars (QSOs), and emission line galaxies (ELGs). We perform…

Early dark energy (EDE) is one of the leading models proposed to resolve the perplexing Hubble tension. Despite extensive scrutiny and testing against various observables, conclusive constraints remain elusive as we await new data. In this…

A supersymmetric hybrid potential model with low energy supersymmetry breaking scale ($ M_{S}\sim 1-10 Tev$) is presented for both dark matter and dark energy. Cold dark matter is associated with a light modulus field ($\sim 10-100 Mev$)…

We consider a model of dark energy/matter unification based on a k-essence type of theory similar to tachyon condensate models. Using an extension of the general relativistic spherical model which incorporates the effects of both pressure…

We implement the transition from dark matter to dark energy in k-essence cosmologies for a very large set of kinetic functions $F$, in a way alternative to recent proposals which use generalized Chaplygin gas and transient models. Here we…