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 …

Recent cosmological observations suggest the existence of a positive cosmological constant
Λ with the magnitude Λ (Gℏ/c3)≈ 10− 123. This review discusses several aspects of the …

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 …

The years elapsed since the First Edition was issued have witnessed an impressive
evolution of some of the applications here considered, maybe not so of the mathematical …

I briefly review our current understanding of dark matter and dark energy. The first part of this
review focusses on issues pertaining to dark matter including observational evidence for its …

I review the problem of dark energy focussing on cosmological constant as the candidate
and discuss what it tells us regarding the nature of gravity. Section 1 briefly overviews the …

In quantum field theory the parameters of the vacuum action are subject to renormalization
group running. In particular, the``cosmological constant''is not a constant in a quantum field …

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 …