Cosmological constant vis-a-vis dynamical vacuum: bold challenging the $\Lambda$CDM

Abstract

Next year we will celebrate 100 years of the cosmological term, $\Lambda$, in Einstein's gravitational field equations, also 50 years since the cosmological constant problem was first formulated by Zeldovich, and almost about two decades of the observational evidence that a non-vanishing, positive, $\Lambda$-term could be the simplest phenomenological explanation for the observed acceleration of the Universe. This mixed state of affairs already shows that we do no currently understand the theoretical nature of $\Lambda$. In particular, we are still facing the crucial question whether $\Lambda$ is truly a fundamental constant or a mildly evolving dynamical variable. At this point the matter should be settled once more empirically and, amazingly enough, the wealth of observational data at our disposal can presently shed true light on it. In this short review I summarize the situation of some of these studies. It turns out that the $\Lambda =$const. hypothesis, despite being the simplest, may well not be the most favored one when we put it in hard-fought competition with specific dynamical models of the vacuum energy. Recently it has been shown that the overall fit to the cosmological observables $SNIa+BAO+H(z)+LSS+BBN+CMB$ do favor the class of "running" vacuum models (RVM's) -- in which $\Lambda =\Lambda (H)$ is a function of the Hubble rate -- against the "concordance" $\Lambda$CDM model. The support is at an unprecedented level of $\sim 4\sigma$ and is backed up with Akaike and Bayesian criteria leading to compelling evidence in favor of the RVM option and other related dynamical vacuum models. I also address the implications of this framework on the possible time evolution of the fundamental constants of Nature.

arXiv comment31 pages, 2 tables, 9 figures. arXiv admin note: text overlap with arXiv:1605.06104

References in corpus (31)

• Varying constants, Gravitation and Cosmology
• Indications of a spatial variation of the fine structure constant
• Hubble parameter measurement constraints on the cosmological deceleration-acceleration transition redshift
• The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: RSD measurement from the power spectrum and bispectrum of the DR12 BOSS galaxies
• Cosmological constant and vacuum energy: old and new ideas
• Indications of a late-time interaction in the dark sector
• First evidence of running cosmic vacuum: challenging the concordance model
• The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: RSD measurement from the LOS-dependent power spectrum of DR12 BOSS galaxies
• Can vacuum decay in our Universe?
• Dark energy: a quantum fossil from the inflationary Universe?
• Hints of dynamical vacuum energy in the expanding Universe
• Dynamical vacuum energy in the expanding Universe confronted with observations: a dedicated study
• Constraints on the Coupling between Dark Energy and Dark Matter from CMB data
• Hubble expansion and structure formation in the "running FLRW model" of the cosmic evolution
• The $\bar{\Lambda }CDM$ cosmology: from inflation to dark energy through running $\Lambda$
• The Constancy of the Constants of Nature: Updates
• Testing models of vacuum energy interacting with cold dark matter
• Vacuum models with a linear and a quadratic term in H: structure formation and number counts analysis
• Dynamical dark energy: scalar fields and running vacuum
• Matter Non-conservation in the Universe and Dynamical Dark Energy
• Planck intermediate results. XXIV. Constraints on variation of fundamental constants
• Background history and cosmic perturbations for a general system of self-conserved dynamical dark energy and matter
• The cosmological constant and entropy problems: mysteries of the present with profound roots in the past
• Varying Alpha
• Fundamental constants and cosmic vacuum: the micro and macro connection
• Cosmological Evolution of Fundamental Constants: From Theory to Experiment
• Utility of observational Hubble parameter data on dark energy evolution
• Fundamental Constants in Physics and Their Time Variation
• The Fundamental Constants in Physics
• Quantum Haplodynamics, Dark Matter and Dark Energy
• Dark matter, dark energy and the time evolution of masses in the Universe

Cited by in corpus (43)

• Challenges for $\Lambda$CDM: An update
• Constraints on the sum of the neutrino masses in dynamical dark energy models with $w(z)\ge -1$ are tighter than those obtained in $\Lambda$CDM
• Evolution of the $f{\sigma }_8$ tension with the Planck15/$\Lambda$CDM determination and implications for modified gravity theories
• $H_0$ Tension, Phantom Dark Energy and Cosmological Parameter Degeneracies
• The $H_0$ tension in light of vacuum dynamics in the Universe
• Cosmological model from the holographic equipartition law with a modified Rényi entropy
• Possible signals of vacuum dynamics in the Universe
• Running vacuum against the $H_0$ and ${\sigma }_8$ tensions
• The Cosmological Constant Problem and Running Vacuum in the Expanding Universe
• Density perturbations for running vacuum: a successful approach to structure formation and to the ${\sigma }_8$-tension
• Hints of a Local Matter Underdensity or Modified Gravity in the Low $z$ Pantheon data
• Dynamical dark energy: scalar fields and running vacuum
• Running vacuum in the Universe: phenomenological status in light of the latest observations, and its impact on the ${\sigma }_8$ and $H_0$ tensions
• Relaxing the ${\sigma }_8$-tension through running vacuum in the Universe
• Weighing neutrinos in the scenario of vacuum energy interacting with cold dark matter: application of the parameterized post-Friedmann approach
• Exploring neutrino mass and mass hierarchy in the scenario of vacuum energy interacting with cold dark matter
• Running vacuum in the Universe and the time variation of the fundamental constants of Nature
• Search for sterile neutrinos in a universe of vacuum energy interacting with cold dark matter
• Quantifying the impacts of future gravitational-wave data on constraining interacting dark energy
• Probing the sign-changeable interaction between dark energy and dark matter with current observations
• Minimal dark energy: key to sterile neutrino and Hubble constant tensions?
• Hyperon resonances coupled to pseudoscalar- and vector-baryon channels
• Thermodynamic constraints on a varying cosmological-constant-like term from the holographic equipartition law with a power-law corrected entropy
• Consistency of Modified Gravity with a decreasing $G_{\mathrm{eff}}(z)$ in a $\Lambda$CDM background
• Models of vacuum energy interacting with cold dark matter: Constraints and comparison
• Generalized thermodynamic constraints on holographic-principle-based cosmological scenarios
• Stringy Running Vacuum Model and current Tensions in Cosmology
• Hints for possible low redshift oscillation around the best fit $\Lambda$CDM model in the expansion history of the Universe
• Reexploration of interacting holographic dark energy model: Cases of interaction term excluding the Hubble parameter
• Constraints on neutrino mass in the scenario of vacuum energy interacting with cold dark matter after Planck 2018
• Two sides of the same coin: sterile neutrinos and dark radiation. Status and perspectives
• Running vacuum versus Holographic dark energy: a cosmographic comparison
• Higgs potential from extended Brans-Dicke theory and the time-evolution of the fundamental constants
• Cosmological Constant Problem and Renormalized Vacuum Energy Density in Curved Background
• Constraints on running vacuum model with $H(z)$ and $f{\sigma }_8$
• Geometrical origins of the Universe dark sector: string-inspired torsion and anomalies as seeds for inflation and dark matter
• Scalar Field Theory Description of the Running Vacuum Model: the Vacuumon
• Testing the nature of Dark Energy with Precision Cosmological constraints
• Weak gravity on a $\Lambda$CDM background
• Cosmological constant, matter, cosmic inflation and coincidence
• Bayesian analysis of running holographic Ricci dark energy
• Implications of Dynamical Dark Energy in the expansion of the Universe and the Structure Formation
• Equivalence of Dark Energy Models: A Theoretical and Bayesian Perspective