Related papers: Hubble Hullabaloo and String Cosmology
The Hubble tension is analyzed in the framework of quantum cosmological approach. It is found that there arises a new summand in the expression for the total energy density stipulated by the quantum Bohm potential. This additional energy…
The discrepancy between low and high redshift Hubble constant $H_0$ measurements is the highest significance tension within the concordance $\Lambda$CDM paradigm. If not due to unknown systematics, the Hubble puzzle suggests a lack of…
The aim of these lectures is to give an introduction to several topics which lie at the intersection of string theory, gravity theory and gravity phenomenology. One successively reviews: (i) the "membrane" approach to the dissipative…
Time delays between multiple images of lensed sources can probe the geometry of the universe. We propose a novel method based on free-form modelling of gravitational lenses to estimate time-delay distances and, in turn, cosmological…
New physics in the neutrino sector might be necessary to address anomalies between different neutrino oscillation experiments. Intriguingly, it also offers a possible solution to the discrepant cosmological measurements of $H_0$ and…
The presence of dark energy in the Universe is inferred directly and indirectly from a large body of observational evidence. The simplest and most theoretically appealing possibility is the vacuum energy density (cosmological constant).…
The mismatch between different independent measurements of the expansion rate of the Universe is known as the Hubble constant ($H_0$) tension, and it is a serious and pressing problem in cosmology. We investigate this tension considering…
An exact solution of Einstein's field equations for a point mass surrounded by a static, spherically symmetric fluid of strings is presented. The solution is singular at the origin. Near the string cloud limit there is a $1/r$ correction to…
Hubble tension and the search for preferred direction are two crucial unresolved issues in modern cosmology. Different measurements of the Hubble constant provide significantly different values, and this is known as the Hubble tension. The…
Recently, a new field of study called fractional cosmology has emerged. It uses fractional calculus to modify the standard derivative equations and change the Friedmann equations. The evolution of cosmic species densities is also affected…
In this review, the status of measurements of the matter density (Omega), the vaccuum energy density or cosmological constant (Lambda), the Hubble constant (H0), and ages of the oldest measured objects (t0) are summarized. Measurements of…
The accelerating expansion of the universe is the most surprising cosmological discovery in many decades. In this short review, we briefly summarize theories for the origin of cosmic acceleration and the observational methods being used to…
The current discrepancy between the Hubble constant $H_0$ derived from the local distance ladder and from the cosmic microwave background is one of the most crucial issues in cosmology, as it possibly indicates unknown systematics or new…
The main goal of string phenomenology is to find realistic models of particle physics and cosmology within string theory. Dark bubble cosmology is an alternative to string compactifications, where our universe lives on a bubble expanding in…
We assess the possibility of determining the Hubble constant H_0 by measuring time delays between multiple images of supernovae gravitationally lensed by rich clusters of galaxies and combining these delay measurements with detailed…
New measurements of the cosmic microwave background (CMB) by the Planck mission have greatly increased our knowledge about the Universe. Dark radiation, a weakly interacting component of radiation, is one of the important ingredients in our…
Our cosmology contains Big Bang relic fluctuations by a loss of time-translation symmetry on a Hubble time scale. The contribution to the vacuum is identified with dynamical dark energy $\Lambda\simeq \alpha_p\Lambda_0$ by an IR coupling…
The dispersion measure-redshift relation of fast radio bursts (FRBs) provides a valuable cosmological probe for constraining the Hubble constant, offering an independent measurement that could help resolve the ongoing Hubble tension. In…
The Hubble parameter $H_0$, is not a univocally-defined quantity: it relates redshifts to distances in the near Universe, but is also a key parameter of the $\Lambda$CDM standard cosmological model. As such, $H_0$ affects several physical…
We extend the results of a previous paper where a model of interacting dark energy, with a cosmological term decaying linearly with the Hubble parameter, is tested against the observed mass power spectrum. In spite of the agreement with…