A number of challenges to the standard Λ CDM model have been emerging during the past
few years as the accuracy of cosmological observations improves. In this review we discuss …

The simplest ΛCDM model provides a good fit to a large span of cosmological data but
harbors large areas of phenomenology and ignorance. With the improvement of the number …

The cosmological constant (CC) term in Einstein's equations, Λ, was first associated to the
idea of vacuum energy density. Notwithstanding, it is well-known that there is a huge, in fact …

We demonstrate that massive fields, such as dark matter, can directly produce a
cosmological evolution of the fundamental constants of nature. We show that a scalar or …

A substantial body of phenomenological and theoretical work over the last few years
strengthens the possibility that the vacuum energy density (VED) of the universe is …

In this paper, we use the type Ia supernovae data to constrain the holographic dark energy
model proposed by Li. We also apply a cosmic age test to this analysis. We consider in this …

We apply the modified acceleration law obtained from Einstein gravity coupled to a massive
skew-symmetric field F μνλ to the problem of explaining galaxy rotation curves without exotic …

Recent studies of quantum field theory in FLRW spacetime suggest that the cause of the
speeding up of the universe is the running vacuum (RV), see Moreno-Pulido and Solà …

Despite the many outstanding cosmological observations leading to a strong evidence for a
non-vanishing cosmological constant (CC) term Λ in the gravitational field equations, the …

We investigate the properties of the FLRW flat cosmological models in which the vacuum
energy density evolves with time, Λ (t). Using different versions of the Λ (t) model, namely …