A rapid transition of $G_{\rm eff}$ at $z_t \simeq 0.01$ as a solution of the Hubble and growth tensions
Valerio Marra, Leandros Perivolaropoulos
备注：
6 pages, 2 figures. Minor modifications (added comments). Accepted in Phys. Rev. D Letters (to appear). The Mathematica files that lead to the production of the figures are available upon request
The mismatch in the value of the Hubble constant from low- and high-redshift observations may be recast as a discrepancy between the low- and high-redshift determinations of the luminosity of Type Ia supernovae, the latter featuring an absolute magnitude which is $\approx 0.2$~mag lower. Here, we propose that a rapid transition in the value of the relative effective gravitational constant $μ_G\equiv\frac{G_{\rm eff}}{G_N}$ at $z_t\simeq 0.01$ could explain the lower luminosity (higher magnitude) of local supernovae, thus solving the $H_0$ crisis. A model that features $μ_G = 1$ for $z \lesssim 0.01$ but $μ_G \simeq 0.9$ for $z \gtrsim 0.01$ is trivially consistent with local gravitational constraints but would raise the Chandrasekhar mass and so decrease the absolute magnitude of Type Ia supernovae at $z \gtrsim 0.01$ by the required value of $\approx 0.2$~mag. Such a rapid transition of the effective gravitational constant would not only resolve the Hubble tension but it would also help resolve the growth tension as it would reduce the growth of density perturbations without affecting the Planck/$Λ$CDM background expansion.
In this letter we propose a reduction of the $H_0$ tension puzzle by means of a theory of minimally modified gravity which is dubbed VCDM. After confronting the theory with the experiments, we find that the data allow for a low-redshift transition in the expansion history of the universe at either $z\simeq 0.3 $ or $z \simeq 1.8\,$, corresponding to one of the two local minima of the total $χ^2$. From the bestfit values the total fitness parameter is improved by $Δχ^2 \simeq 12$, for the data set considered. We then infer the local Hubble expansion rate today within this theory by means of low…
The $Λ$CDM prediction of $S_8\equivσ_8(Ω_m/0.3)^{0.5}$ -- where $σ_8$ is the root mean square of matter fluctuations on a 8 $h^{-1}$Mpc scale -- once calibrated on Planck CMB data is $2-3σ$ lower than its direct estimate by a number of weak lensing surveys. In this paper, we explore the possibility that the '$S_8$-tension' is due to a non-thermal hot dark matter (HDM) fractional contribution to the universe energy density leading to a power suppression at small-scales in the matter power spectrum. Any HDM models can be characterized by its effective mass $ m_{sp}^{\rm eff}$ and its contributio…
A rapid phantom transition of the dark energy equation of state parameter $w$ at a transition redshift $z_t<0.1$ of the form $w(z)=-1+Δw\;Θ(z_t-z)$ with $Δw<0$ can lead to a higher value of the Hubble constant while closely mimicking a Planck18/$Λ$CDM form of the comoving distance $r(z)=\int_0^z\frac{dz'}{H(z')}$ for $z>z_t$. Such a transition however would imply a significantly lower value of the SnIa absolute magnitude $M$ than the value $M_C$ imposed by local Cepheid calibrators at $z<0.01$. Thus, in order to resolve the $H_0$ tension it would need to be accompanied by a similar transition …
It is shown, from the two independent approaches of McCrea-Milne and of Zeldovich, that one can fully recover the set equations corresponding to the relativistic equations of the expanding universe of Friedmann-Lemaitre-Robertson-Walker geometry. Although similar, the Newtonian and relativistic set of equations have a principal difference in the content and hence define two flows, local and global ones, thus naturally exposing the Hubble tension at the presence of the cosmological constant Λ. From this, we obtain absolute constraints on the lower and upper values for the local Hubble parameter…
We use an up to date compilation of Tully-Fisher data to search for transitions in the evolution of the Tully-Fisher relation. Using an up to date data compilation, we find hints at $\approx 3σ$ level for a transition at critical distances $D_c \simeq 9 Mpc$ and $D_c \simeq 17 Mpc$. We split the full sample in two subsamples according to the measured galaxy distance with respect to a splitting distance $D_c$ and identify the likelihood of the best fit slope and intercept of one sample with respect to the best fit corresponding values of the other sample. For $D_c \simeq 9 Mpc$ and $D_c \simeq …
Blue-tilted spectral running and the JWST early galaxy tension
Graduate University for Advanced Studies (SOKENDAI)（高级研究大学院大学）；High Energy Accelerator Research Organization (KEK)（高能加速器研究机构）；National Institute of Technology (KOSEN), Kochi College（国立高等专门学校高知工业高等专门学校）；Tohoku University（东北大学）；Division of Science, National Astronomical Observatory of Japan（日本国立天文台理学科）；The University of Tokyo（东京大学）；Kavli IPMU (WPI), UTIAS, The University of Tokyo（东京大学卡弗里宇宙物理起源研究所（WPI））；Saga University（佐贺大学）
We develop a new phenomenological model that addresses current tensions between observations of the early and late Universe. Our scenario features: (i) a decaying dark energy fluid (DDE), which undergoes a transition at $z \sim 5,000$, to raise today's value of the Hubble parameter -- addressing the $H_0$ tension, and (ii) an ultra-light axion (ULA), which starts oscillating at $z\gtrsim 10^4$, to suppress the matter power spectrum -- addressing the $S_8$ tension. Our Markov Chain Monte Carlo analyses show that such a Dark Sector model fits a combination of Cosmic Microwave Background (CMB), B…
The $H_0$-tension problem poses a confrontation of dark energy driving late-time cosmological expansion measured by the Hubble parameter $H(z)$ over an extended range of redshifts $z$. Distinct values $H_0\simeq 73$ km\,s$^{-1}$Mpc$^{-1}$ and $H_0\simeq 68$ km\,s$^{-1}$Mpc$^{-1}$ obtain from surveys of the Local Universe and, respectively, $Λ$CBM analysis of the CMB. These are representative of accelerated expansion with $H^\prime(0)\simeq0$ by $Λ=ω_0^2$ and, respectively, $H^\prime(0)>0$ in $Λ$CDM, where $ω_0=\sqrt{1-q}H$ is a fundamental frequency of the cosmological horizon in a Friedmann-R…
In prerecombination resolutions of the Hubble tension, such as early dark energy, new physics before recombination shifts the values of relevant cosmological parameters so that the models can fit with cosmic microwave background and baryon acoustic oscillations observations as well as $Λ$CDM does. In this paper, we clarify how the parameter shifts are related with $δH_0$, particularly we find the shift of primordial scalar spectral index scales as ${δn_s}\simeq 0.4{δH_0\over H_0}$ by performing the Monte Carlo Markov chain analysis with the Planck2018+BAO+Pantheon+R19+Keck Array/BICEP dataset.…
We study the fit of cosmological models with two additional free parameters $N_\mathrm{eff}$ and $ξ_e$ in addition to the parameters of $Λ$CDM. We introduce extra radiation components such as hot axions or sterile neutrinos in addition to the energy density of neutrinos with large neutrino degeneracy. Then, a larger $N_\mathrm{eff}$ is allowed without spoiling Big Bang Nucleosynthesis (BBN), as positive neutrino degeneracy $ξ_e$ could improve BBN fit. By analysing the data from Planck, baryon acoustic oscillation (BAO), BBN and type-Ia supernovae (SNeIa), it can be seen that the Hubble tension…
We propose a new model of Early Dark Energy (EDE) as a solution to the Hubble tension in cosmology, the apparent discrepancy between local measurements of the Hubble constant $H_0\simeq 74$ km s$^{-1}$ Mpc$^{-1}$ and $H_0\simeq 67$ km s$^{-1}$ Mpc$^{-1}$ inferred from the Cosmic Microwave Background (CMB). In Chain EDE, the Universe undergoes a series of first order phase transitions, starting at a high energy vacuum in a potential, and tunneling down through a chain of every lower energy metastable minima. As in all EDE models, the contribution of the vacuum energy to the total energy density…
We reanalyze the recently released SH0ES data for the determination of $H_0$. We focus on testing the homogeneity of the Cepheid+SnIa sample and the robustness of the results in the presence of new degrees of freedom in the modeling of Cepheids and SnIa. We thus focus on the four modeling parameters of the analysis: the fiducial luminosity of SnIa $M_B$ and Cepheids $M_W$ and the two parameters ($b_W$ and $Z_W$) standardizing Cepheid luminosities with period and metallicity. After reproducing the SH0ES baseline model results, we allow for a transition of the value of any one of these parameter…
The cosmological constant is estimated by considering the surface tension of supervoids in a void-dominated cosmic fluid by which we can get a possible source of dark energy. Looking at voids as bubbles, we define the concept of surface tension which is shown to have an almost constant value for supervoids that are enclosed by superclusters. The surface tensions of voids are computed by dimensional method for galaxies and superclusters with different values for each group. At large scale which vast voids are dominant the positive cosmological constants obtained of order $ (\simeq+10^{-52} {\rm…
Addressing the discrepancy between the late and early time measurements of the Hubble parameter, $H_0$, and the so-called $S_8$ parameter has been a challenge in precision cosmology. Several models are present to address these tensions, but very few of them can do so simultaneously. In the past, we have suggested Banks-Zaks/Unparticles as an emergent Dark Energy model and claimed that it can ameliorate the Hubble tension. In this work, we test this claim and perform a likelihood analysis of the model and its parameters are given current data and compare it to $Λ$CDM. The model offers a possibl…
Recent weak lensing surveys have revealed that the direct measurement of the parameter combination $S_8\equivσ_8(Ω_m/0.3)^{0.5}$ -- where $σ_8$ is a measure of the amplitude of matter fluctuations on 8 $h^{-1}$Mpc scales -- is $\sim3σ$ discrepant with the value reconstructed from cosmic microwave background (CMB) data assuming the $Λ$CDM model. In this article, we show that it is possible to resolve the tension if dark matter (DM) decays with a lifetime of $Γ^{-1} \simeq 55 \ \text{Gyrs}$ into one massless and one massive product, and transfers a fraction $\varepsilon\simeq 0.7 \ \%$ of its re…
We present updated constraints on the variation of the fine structure constant, $α_{\rm EM}$, and effective electron rest mass, $m_{\rm e}$, during the cosmological recombination era. These two fundamental constants directly affect the ionization history at redshift $z\simeq 1100$ and thus modify the temperature and polarisation anisotropies of the cosmic microwave background (CMB) measured precisely with {\it Planck }. The constraints on $α_{\rm EM}$ tighten slightly due to improved {\it Planck} 2018 polarisation data but otherwise remain similar to previous CMB analysis. However, a compariso…
A $Λ$CDM Extension Explaining the Hubble Tension and the Spatial Curvature $Ω_{k,0} = -0.012 \pm 0.010$ Measured by the Final PR4 of the Planck Mission
Many late time approaches for the solution of the Hubble tension use late time smooth deformations of the Hubble expansion rate $H(z)$ of the Planck18/$Λ$CDM best fit to match the locally measured value of $H_0$ while effectively keeping the comoving distance to the last scattering surface and $Ω_{0m} h^2$ fixed to maintain consistency with Planck CMB measurements. A well known problem of these approaches is that they worsen the fit to low $z$ distance probes. Here we show that another problem of these approaches is that they worsen the level of the $Ω_{0m}-σ_8$ growth tension. We use the gene…
New Early Dark Energy (NEDE) is a component of vacuum energy at the electron volt scale, which decays in a first-order phase transition shortly before recombination [arXiv:1910.10739]. The NEDE component has the potential to resolve the tension between recent local measurements of the expansion rate of the Universe using supernovae (SN) data and the expansion rate inferred from the early Universe through measurements of the cosmic microwave background (CMB) when assuming $Λ$CDM. We discuss in depth the two-scalar field model of the NEDE phase transition including the process of bubble percolat…
Recent low-redshift observations give value of the present-time Hubble parameter $H_{0}\simeq 74~\rm{km s}^{-1}\rm{Mpc}^{-1}$, roughly 10\% higher than the predicted value $H_{0}=67.4~\rm{km s}^{-1}\rm{Mpc}^{-1}$ from Planck's observations of the Cosmic Microwave Background radiation~(CMB) and the $Λ$CDM model. Phenomenologically, we show that by adding an extra component X with negative density in the Friedmann equation, it can relieve the Hubble tension without changing the Planck's constraint on the matter and dark energy densities. For the extra negative density to be sufficiently small, i…
The heliocentric redshifts ($z_\mathrm{hel}$) reported for 150 Type Ia supernovae in the Pantheon compilation are significantly discrepant from their corresponding values in the JLA compilation. Both catalogues include corrections to the redshifts and magnitudes of the supernovae to account for the motion of the heliocentric frame relative to the `CMB rest frame', as well as corrections for the directionally coherent bulk motion of local galaxies with respect to this frame. The latter is done employing modelling of peculiar velocities which assume the $Λ$CDM cosmological model but nevertheless…
We explore a model introduced by Cyr-Racine, Ge, and Knox (arXiv:2107.13000(2)) that resolves the Hubble tension by invoking a ``mirror world" dark sector with energy density a fixed fraction of the ``ordinary" sector of Lambda-CDM. Although it reconciles cosmic microwave background and large-scale structure observations with local measurements of the Hubble constant, the model requires a value of the primordial Helium mass fraction that is discrepant with observations and with the predictions of Big Bang Nucleosynthesis (BBN). We consider a variant of the model with standard Helium mass fract…
We address the $\simeq 4.4σ$ tension between local and the CMB measurements of the Hubble Constant using simulated Type Ia Supernova (SN) data-sets. We probe its directional dependence by means of a hemispherical comparison through the entire celestial sphere as an estimator of the $H_0$ cosmic variance. We perform Monte Carlo simulations assuming isotropic and non-uniform distributions of data points, the latter coinciding with the real data. This allows us to incorporate observational features, such as the sample incompleteness, in our estimation. We obtain that this tension can be alleviate…
In this paper, we explore in detail the cosmological implications of an abelian $L_μ-L_τ$ gauge extension of the Standard Model featuring a light and weakly coupled $Z'$. Such a scenario is motivated by the longstanding $\sim \, 4 σ$ discrepancy between the measured and predicted values of the muon's anomalous magnetic moment, $(g-2)_μ$, as well as the tension between late and early time determinations of the Hubble constant. If sufficiently light, the $Z'$ population will decay to neutrinos, increasing the overall energy density of radiation and altering the expansion history of the early uni…
We investigate constraints on the Hubble constant ($H_0$) using Baryon Acoustic Oscillations (BAO) and baryon density measurements from Big Bang Nucleosynthesis (BBN). We start by investigating the tension between galaxy BAO measurements and those using the Lyman-$α$ forest, within a Bayesian framework. Using the latest results from eBOSS DR14 we find that the probability of this tension being statistical is $\simeq6.3\%$ assuming flat $Λ$CDM. We measure $H_0 = 67.6\pm1.1$ km s$^{-1}$ Mpc$^{-1}$, with a weak dependence on the BBN prior used, in agreement with results from Planck Cosmic Microwa…
Early Dark Energy (EDE) contributing a fraction $f_{\rm EDE}(z_c)\sim 10 \%$ of the energy density of the universe around $z_c\simeq 3500$ and diluting as or faster than radiation afterwards, can provide a resolution to the Hubble tension, the $\sim 5σ$ discrepancy between the $H_0$ value derived from early- and late-universe observations within $Λ$CDM. However, it has been pointed out that Large-Scale Structure (LSS) data, which are in $\sim3σ$ tension with $Λ$CDM and EDE cosmologies, might alter these conclusions. We reassess the viability of the EDE against a host of high- and low-redshift …
University of Trento（特伦托大学）；Trento Institute for Fundamental Physics and Applications (TIFPA)-INFN（特伦托基础物理与应用研究所（TIFPA）-意大利国家核物理研究所）；Istanbul Technical University（伊斯坦布尔理工大学）
Varying fundamental constants (VFC) [e.g., the fine-structure constant, $α_{\rm EM}$] can arise in numerous extended cosmologies. Through their effect on the decoupling of baryons and photons during last scattering and reionisation, these models can be directly constrained using measurements of the cosmic microwave background (CMB) temperature and polarization anisotropies. Previous investigations focused mainly on time-independent changes to the values of fundamental constants. Here we generalize to time-dependent variations. Instead of directly studying various VFC parameterizations, we perf…
We investigate whether the $4.4σ$ tension on $H_0$ between SH$_{0}$ES 2019 and Planck 2018 can be alleviated by a variation of Newton's constant $G_N$ between the early and the late Universe. This changes the Hubble rate before recombination, similarly to adding $ΔN_{\rm eff}$ extra relativistic degrees of freedom. We implement a varying $G_N$ in a scalar-tensor theory of gravity, with a non-minimal coupling $(M^2+βϕ^2)R$. If the scalar $ϕ$ starts in the radiation era at an initial value $ϕ_I \sim 0.5~M_p$ and with $β<0$, a dynamical transition occurs naturally around the epoch of matter-radia…
Precise measurements of the cosmic microwave background (CMB) power spectrum are in excellent agreement with the predictions of the standard $Λ$CDM cosmological model. However, there is some tension between the value of the Hubble parameter $H_0$ inferred from the CMB and that inferred from observations of the Universe at lower redshifts, and the unusually small value of the dark-energy density is a puzzling ingredient of the model. In this paper, we explore a scenario with a new exotic energy density that behaves like a cosmological constant at early times and then decays quickly at some crit…
Revisiting the Matter Creation Process: Observational Constraints on Gravitationally Induced Dark Energy and the Hubble Tension
SISSA-International School for Advanced Studies（国际高等研究学院）；INFN, Sezione di Trieste（意大利国家核物理研究所的里雅斯特分部）；Institute of Space Sciences (ICE,CSIC)（空间科学研究所）；Universidad Complutense de Madrid（马德里康普顿斯大学）；Istanbul Technical University（伊斯坦布尔理工大学）；ENEA, Nuclear Department（意大利国家新能源与可再生能源署核能部）；Sapienza University of Rome（罗马智慧大学）；University of Sheffield（谢菲尔德大学）
Can cosmic voids ease the Hubble tension? Local expansion in $w_0w_a$CDM
Università degli Studi di Napoli “Federico II”（那不勒斯费德里科二世大学）；INFN Sezione di Napoli（意大利国家核物理研究所那不勒斯分部）；ICTP, International Centre for Theoretical Physics（国际理论物理中心）；Center for Computational Astrophysics, Flatiron Institute（平托研究所计算天体物理学中心）
The current $>3σ$ tension between the Hubble constant $H_0$ measured from local distance indicators and from cosmic microwave background is one of the most highly debated issues in cosmology, as it possibly indicates new physics or unknown systematics. In this work, we explore whether this tension can be alleviated by the sample variance in the local measurements, which use a small fraction of the Hubble volume. We use a large-volume cosmological $N$-body simulation to model the local measurements and to quantify the variance due to local density fluctuations and sample selection. We explicitl…
Allowing for a nonvanishing spin tensor for cold dark matter ($ω_{\mathrm{DM}}=0$) has the consequence of giving rise to an effective $\mathrm{FLRW}$ dynamics with a small negative barotropic constant for an effective dark matter density ($-1/3<ω_{\mathrm{eff}}\leq0$). This turns out to solve the Hubble parameter tension in a straightforward way.
Probing the Hubble Tension with an Infinite-Future Condition on the Hubble Parameter
Institute for Frontiers in Astronomy and Astrophysics, Beijing Normal University（北京师范大学天文与前沿科学研究院）；School of Physics and Astronomy, Beijing Normal University（北京师范大学物理与天文学院）；Department of Astronomy, University of Science and Technology of China（中国科学技术大学天文学系）；Kavli Institute for Astronomy and Astrophysics, Peking University（北京大学科维理天文与天体物理研究所）；Department of Astronomy, School of Physics, Peking University（北京大学物理学院天文学系）
本文研究了在37个宇宙钟测量数据上对高斯过程（GP）重构H(z)时施加无限未来的条件的影响，结果表明H0值从68.71±6.08降低到约64.67-65.86±4.45-4.85 km s^{-1} Mpc^{-1}，同时H0与Planck ΛCDM值的偏离较小，但与局部距离阶梯测量的偏离增大。
