Abstract The standard Λ Cold Dark Matter (ΛCDM) cosmological model provides a good
description of a wide range of astrophysical and cosmological data. However, there are a …

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 …

Early data from the James Webb Space Telescope (JWST) have revealed a bevy of high-
redshift galaxy candidates with unexpectedly high stellar masses. An immediate concern is …

We review the current status of Early Dark Energy (EDE) models proposed to resolve the
“Hubble tension”, the discrepancy between “direct” measurements of the current expansion …

The Hubble tension has now grown to a level of significance which can no longer be
ignored and calls for a solution which, despite a huge number of attempts, has so far eluded …

The Λ CDM model provides a good fit to most astronomical observations but harbors large
areas of phenomenology and ignorance. With the improvements in the precision and …

We investigate the constraints on early dark energy (EDE) by combining the most recent
CMB observations available, ACT DR4, SPT-3G, and Planck2018 (ℓ TT, max= 1000) data …

The early dark energy (EDE) solution to the Hubble tension comes at the cost of an
increased clustering amplitude that has been argued to worsen the fit to galaxy clustering …

I review and discuss the possible implications for inflation resulting from considering new
physics in light of the Hubble tension. My study is motivated by a simple argument that the …

Polarization of the cosmic microwave background (CMB) is sensitive to new physics
violating parity symmetry, such as the presence of a pseudoscalar “axionlike” field. Such a …