Hubble Tension Research Articles

Can Hubble tension be eased by invoking a finite range for gravity?

The estimation of the Hubble constant in the past few decades has increasingly become more accurate with the advancement of new techniques. However, its value seems to depend on the epoch at which the measurements are made. The Planck estimate of the Hubble constant from the observations of the cosmic microwave background radiation in the early universe is about [Formula: see text], whereas that obtained from the distance indicators at the current epoch is [Formula: see text]. This discrepancy between the two groups of measurement is termed as the Hubble tension which has gained much attention in the past few decades with growing significance as measurements from both, the early and the late universe, studies continue to produce results with increasing precision. In this work, we propose a modification to gravity by considering a finite range gravitational field as an alternate explanation for this discrepancy in the value of the Hubble constant.

A comprehensive forecast for cosmological parameter estimation using joint observations of gravitational waves and short γ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\gamma $$\\end{document}-ray bursts

In the third-generation (3G) gravitational-wave (GW) detector era, multi-messenger GW observation for binary neutron star (BNS) merger events can exert great impacts on exploring cosmic expansion history. In this work, we comprehensively explore the potential of 3G GW standard siren observations in cosmological parameter estimations by considering 3G GW detectors and the future short γ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\gamma $$\\end{document}-ray burst (GRB) detector THESEUS-like telescope joint observations. Based on a 10-year observation of different detection strategies, we predict that the numbers of detectable GW-GRB events are 334–674 with the redshifts z<3.5\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$z<3.5$$\\end{document} and the inclination angles ι<15∘\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\iota <15^{\\circ }$$\\end{document}. For the cosmological analysis, we consider the Λ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Lambda $$\\end{document}CDM, wCDM, w0wa\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$w_0w_a$$\\end{document}CDM, and interacting dark energy (IDE) models. We find that GW can tightly constrain the Hubble constant with precision of 0.345–0.065%, but does not perform well in constraining other cosmological parameters. Fortunately, GW detection could effectively break the cosmological parameter degeneracies generated by the mainstream EM observations, CMB + BAO + SN (CBS). When combining mock GW data with CBS data, CBS + GW can tightly constrain the equation of state of dark energy w with a precision of 1.26%, close to the standard of precision cosmology. Meanwhile, the addition of GW to CBS could improve constraints on cosmological parameters by 34.2–94.9%. In conclusion, GW standard siren observations from 3G GW detectors could play a crucial role in helping solve the Hubble tension and probe the fundamental nature of dark energy.

Constraining holographic dark energy and analyzing cosmological tensions

We investigate cosmological constraints on the holographic dark energy (HDE) using the state-of-the-art cosmological datasets: Planck CMB angular power spectra and weak lensing power spectra, Atacama Cosmology Telescope (ACT) temperature power spectra, baryon acoustic oscillation (BAO) and redshift-space distortion (RSD) measurements from six-degree-field galaxy survey and Sloan Digital Sky Survey (DR12 & DR16) and the Cepheids-Supernovae measurement from SH0ES team (R22). We also examine the HDE model and ΛCDM with and without Neff (effective number of relativistic species) being treated as a free parameter. We find that the HDE model can relieve the tensions of H0 and S8 to certain degrees. With “Planck+ACT+BAO+RSD” datasets, the constraints are H0=69.70±1.39km s−1Mpc−1 and S8=0.823±0.011 in HDE model, which brings down the Hubble tension down to 1.92σ confidence level (C.L.) and the S8 tension to (1−2)σ C.L. By adding the R22 data, their values are improved as H0=71.86±0.93km s−1Mpc−1 and S8=0.813±0.010, which further brings the Hubble tension down to 0.85σ C.L. and relieves the S8 tension. We also quantify the goodness-of-fit of different models with Akaike information criterion (AIC) and Bayesian information criterion (BIC), and find that the HDE agrees with the observational data better than the ΛCDM and other extended models (treating Neff as free for fitting).

Investigating early dark energy with new observations

This paper mainly presents updated constraints on several types of early dark energy (EDE) models proposed by V. Pettorino et al. using observations of cosmic microwave background radiation (CMB) from Planck satellite, the Pantheon Type Ia supernovae (SNIa) sample, and baryon acoustic oscillation (BAO) measurements. The results yield stringent upper limits on the constant EDE fraction parameter Ωe. While the present equation of state (EoS) of dark energy w0 in the EDE1 model suggests a mild tendency towards a value less than −1, these models remain compatible with the ΛCDM scenario. Partly as a result of this slight tendency towards phantom late-time physics, EDE1 model supports a higher Hubble constant value, potentially narrowing the Hubble tension gap. The global fitting results also align with the notion that the constraint ability on Ωe weakens when dark energy is present only over a limited period after last scattering. Furthermore, by using the formalism of Fisher information matrix, we forecast uncertainties in the measured parameters of EDE models from the next-generation “Stage 4” CMB (CMB-S4) experiment. Forecasted precision of w0 and Ωe surpasses certain prior works, and most other basic parameters exhibit significantly higher limit precision compared to Planck 2018 results within the ΛCDM framework. To confirm the presence of EDE within the EDE1∼EDE4 parameterization frameworks, further advancements in observations are crucial.

Inflation, the Hubble tension, and early dark energy: An alternative overview

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 constraints on inflationary parameters, most typically the spectral index ns, depend to some extent on the cosmological framework. To avoid broadening the uncertainties resulting from marginalizing over additional parameters (typical in many alternative models), I first adopt the same alternative viewpoint of previous studies and analyze what happens if a physical theory can extra parameters to nonstandard values. Focusing on the dark energy equation of state w and the effective number of relativistic species Neff, I confirm that physical theories able to fix w≈−1.2 or Neff≈3.9 produce values of H0 from Cosmic Microwave Background and Baryon Acoustic Oscillations in line with the local distance ladder estimate. While in the former case I do not find any relevant implications for inflation, in the latter scenarios, I observe a shift toward ns≈1. From a model-selection perspective, both cases are strongly disfavored compared to Λ cold dark matter. However, models with Neff≈3.3–3.4 could bring the H0 tension down to ∼3σ while being moderately disfavored. Yet, this is enough to change the constraints on inflation so that the most accredited models (e.g., Starobinsky inflation) would no longer be favored by data. I then focus on Early Dark Energy (EDE), arguing that an EDE fraction fEDE∼0.04–0.06 (only able to mildly reduce the H0 tension down to ∼3σ) could already require a similar change in perspective on inflation. In fact, performing a full joint analysis of EDE and Starobinsky inflation, I find that the two models can hardly coexist for fEDE≳0.06. Published by the American Physical Society 2024

Hubble tension and gravitational self-interaction

One of the most important problems vexing the ΛCDM cosmological model is the Hubble tension. It arises from the fact that measurements of the present value of the Hubble parameter performed with low-redshift quantities, e.g. the Type IA supernova, tend to yield larger values than measurements from quantities originating at high-redshift, e.g. fits of cosmic microwave background radiation. It is becoming likely that the discrepancy, currently standing at 5σ, is not due to systematic errors in the measurements. Here we explore whether the self-interaction of gravitational fields in General Relativity, which are traditionally neglected when studying the evolution of the Universe, can contribute to explaining the tension. We find that with field self-interaction accounted for, both low- and high-redshift data are simultaneously well-fitted, thereby showing that gravitational self-interaction yield consistent H 0 values when inferred from SnIA and cosmic microwave background observations. Crucially, this is achieved without introducing additional parameters.

Contribution of Majoron to Hubble Tension in Gauged U(1)Lμ – Lτ Model

Abstract In this paper, we analyze parameter regions that can alleviate the Hubble tension in the U(1)$_{L_\mu - L_\tau }$ model with broken lepton number U(1)$_L$ symmetry. As new particles, this model has a U(1)$_{L_\mu - L_\tau }$ gauge boson $Z^{\prime }$ and a Majoron $\phi$, which can affect the early universe and the effective number of neutrino species $N_\textrm{eff}$. If $Z^{\prime }$ and $\phi$ simultaneously exist in the early universe, $Z^{\prime }\,$–$\, \phi$ direct reaction processes such as $Z^{\prime }\nu _\alpha \leftrightarrow \phi \bar{\nu }_\beta$ and $Z^{\prime } \phi \leftrightarrow \bar{\nu }_\alpha \bar{\nu }_\beta$ occur. The comparison of $N_\textrm{eff}$ between the cases with and without the $Z^{\prime }\,$–$\, \phi$ direct reaction processes shows that these processes make a small contribution of $\mathcal {O}(10^{-4})$ to $N_\textrm{eff}$, and it does not need to be considered for the alleviation of the Hubble tension. Based on these facts, we calculated $N_\textrm{eff}$ for various Majoron parameters without the $Z^{\prime }\,$–$\, \phi$ direct reaction processes to search for parameters that could alleviate the Hubble tension. As a result, we found that the U(1)$_{L_\mu - L_\tau }$ gauge boson and Majoron can alleviate the Hubble tension in some parameter regions, and there is a nontrivial indirect synergy contribution between $Z^{\prime }$ and $\phi$, although the contribution from $Z^{\prime }\,$–$\, \phi$ direct reaction processes is negligible.

An oscillating Chern-Simons universe crossing the phantom divide line and alleviating the Hubble tension

In order to alleviate the Hubble tension, we propose a new law for the Hubble parameter that varies periodically with time and we study the validity of the dynamics of a flat Friedmann–Robertson–Walker Universe in the context of a generalized Chern–Simons modified gravity (CSMG). We prove that for specific numerical values of the free parameters in the theory, the phantom divide line is crossed and the universe undergoes decelerating expansion and accelerating expansion alternately without singularity. The deceleration and the jerk parameters oscillate also around numerical values in agreement with astronomical BAO+Pantheon SNeIa+Cosmic Chronometers observations.

Restoring cosmological concordance with axion-like early dark energy and dark matter characterized by a constant equation of state?

The Hubble tension persists as a challenge in cosmology. Even early dark energy (EDE) models, initially considered the most promising for alleviating the Hubble tension, fall short of addressing the issue without exacerbating other tensions, such as the S 8 tension. Considering that a negative dark matter (DM) equation of state (EoS) parameter is conducive to reduce the value of the σ 8 parameter, we extend the axion-like EDE model in this paper by replacing the cold dark matter (CDM) with DM characterized by a constant EoS w dm (referred to as WDM hereafter). We then impose constraints on this axion-like EDE extension model, along with three other models: the axion-like EDE model, ΛWDM, and ΛCDM. These constraints are derived from a comprehensive analysis incorporating data from the Planck 2018 cosmic microwave background, baryon acoustic oscillations, and the Pantheon compilation, as well as a prior on H 0 (i.e. H 0 = 73.04 ± 1.04, based on the latest local measurement by Riess et al) and a Gaussianized prior on S 8 (i.e. S 8 = 0.766 ± 0.017, determined through the joint analysis of KID1000+BOSS+2dLenS). We find that although the new model maintains the ability to alleviate the Hubble tension to ∼1.4σ, it still exacerbates the S 8 tension to a level similar to that of the axion-like EDE model.

Analysis of the Hubble Tension and Modifications to the Standard Cosmological Model

The Hubble constant is crucial to the knowledge of the universe’s nature and expansion, remaining as an active area for research in the recent decades. Cosmological microwave background observations revealed a lower value of 67–69 km-1s-1Mpc for the Hubble constant, but local data showed a higher value of 73–75 km-1s-1Mpc. This study focuses on the Hubble constant and its measurement, systematic uncertainties, observed tension, and potential modifications to the standard cosmological model. To be specific, this paper aims to address the tension between different measurement methods, which are Cepheid variables and supernovae, Baryon Acoustic Oscillations, and Gravitational waves, and understand systematic uncertainties. Results show discrepancies in Hubble constant values, indicating potential modifications to the standard cosmological model. Prospects include exploring alternative cosmological components and enhanced detection and computation methods. The study's implications lie in advancing the understanding of the expanding universe and guiding future research directions regarding to Hubble tension measurement.

Solution of the dark matter riddle within standard model physics: from black holes, galaxies and clusters to cosmology

It is postulated that the energy density of the (quantum) vacuum acts firstly as dark energy and secondly as a part of dark matter. Assisted by electric fields arising from a small charge mismatch in the cosmic plasma, it can condense on mass concentrations. No longer participating in the cosmic expansion, this constitutes “electro-aether-energy” (EAE), “electro-zero-point-energy” or “electro-vacuum-energy”, which solves the dark matter riddle without new physics. A radial electric field of 1 kV/m is predicted in the Galaxy. For proper electric fields, EAE can cover the results deduced with MOND. An instability allows a speedy filling of dark matter cores. Hydrostatic equilibrium in galaxy clusters is obeyed. Flowing in aether energy of explains why black holes become supermassive, do not have mass gaps and overcome the final parsec problem. Rupture of charged clouds reduces, e.g., the primordial baryon cloud to the cosmic web. The large coherence scale of the electric field acts as a scaffold for gentle galaxy formation and their vast polar structures. In galaxy merging and bars, there occurs no dynamical friction. At cosmological scales, EAE acts as pressureless dark matter. Its amount increases in time, which likely solves the Hubble tension by its late time physics. A big crunch can occur. Of the large cosmological constant injected at the Big Bang, a small part kept that form, without fine-tuning.

A gravitational constant transition within cepheids as supernovae calibrators can solve the Hubble tension

Local universe measurements of the Hubble constant H 0 using SNe Ia with Cepheids as calibrators yield a value of H 0 = 73.04 ± 1.04 km s-1 Mpc-1, which is in tension with the value of H 0 inferred from the Cosmic Microwave Background and other higher redshift probes.In ref. [1], the authors proposed a rapid transition in the value of the effective Newtonian gravitational constant G in order to alleviate the Hubble tension. The transition point was chosen so as to only affect distance estimates to Hubble flow SNe. However, in this study, the authors made the assumption that SNe Ia peak luminosity L increases with Chandrasekhar mass Mc . This hypothesis contradicts a previous semi-analytic study of SN light curves in the presence of a G-transition [2] which concluded that there is an inverse relationship between L and Mc . Motivated by the results of ref. [1] and [2], we propose a hypothesis of a sudden recent change in the effective Newtonian gravitational constant G at an epoch which corresponds to a smaller look-back distance between ∼ 7–80 Mpc. A transition in G at these distances would affect both our estimates of the distances to Cepheids in calibrator galaxies, as well as to the Hubble flow supernovae. Upon fitting the observational data to this hypothesis, we find three interesting results: (i) we find mild evidence for a G-transition at 22.4 Mpc (73 million years ago) which is preferred (using certain estimators) by the calibrator type Ia SNe data over no G-transition, (ii) the Hubble constant inferred under this hypothesis is in good agreement with the value obtained from the CMB for a 4% larger value of G at earlier times, thus potentially resolving the Hubble tension, (iii) we obtain a fit to the scaling relationship between SN peak luminosity L and Chandrasekhar mass Mc , as L ∝ Mc -1.68 ± 0.68, which is in good agreement with the prediction of the theoretical study of ref. [2]. We also discuss how other probes could be used to verify this transition in the value of G.

Hubble tension in a nonminimally coupled curvature-matter gravity model

The presently open problem of the Hubble tension is shown to be removed in the context of a modified theory of gravity with a non-minimal coupling between curvature and matter. By evolving the cosmological parameters that match the cosmic microwave background data until their values from direct late-time measurements, we obtain an agreement between different experimental methods without disrupting their individual validity. These modified gravity models are shown to provide adequate fits for other observational data from recent astrophysical surveys and to reproduce the late-time accelerated expansion of the Universe without the inclusion of a cosmological constant. This compatibility with observations presents further evidence of the versatility of these models in mimicking diverse cosmological phenomena in a unified manner.

Gravitational wave probes of Barrow cosmology with LISA standard sirens

We study the Barrow cosmological model, which proposes that quantum gravity effects create a complex, fractal structure for the universe's apparent horizon. We leverage the thermodynamics-gravity conjecture. By applying the Clausius relation to the apparent horizon of the Friedmann-Lemaître-Robertson-Walker universe within this framework, we derive modified field equations where the Barrow entropy is linked to the horizon. We assess the Barrow cosmology against current observations — cosmic microwave background, supernovae, and baryon acoustic oscillations data — and include projections for future Laser Interferometer Space Antenna (LISA) standard sirens (SS). Our numerical results suggest a modest improvement in the Hubble tension for Barrow cosmology with phantom dark energy behavior, compared to the standard cosmological model. Furthermore, incorporating simulated LISA SS data alongside existing observational constraints tightens the limitations on cosmological parameters, particularly the deformation exponent.

Improved Planck Constraints on Axionlike Early Dark Energy as a Resolution of the Hubble Tension.

Axionlike early dark energy (EDE) as an extension to Λ cold dark matter (ΛCDM) has been proposed as a possible solution to the "Hubble tension." We revisit this model using a new cosmic microwave background (CMB) temperature and polarization likelihood constructed from the Planck NPIPE data release. In a Bayesian analysis, we find that the maximum fractional contribution of EDE to the total energy density is f_{EDE}<0.061 (without SH0ES) over the redshift range z∈[10^{3},10^{4}] and that the Hubble constant is constrained to lie within the range 66.9<H_{0}<69.5 km s^{-1} Mpc^{-1} (both at 95%C.L.). The data therefore favor a model close to ΛCDM, leaving a residual tension of 3.7σ with the SH0ES Cepheid-based measurement of H_{0}. A comparison with the likelihood profile shows that our conclusions are robust to prior-volume effects. Our new CMB likelihood provides no evidence in favor of a significant EDE component.

Breaking the baryon-dark matter degeneracy in a model-independent way through the Sunyaev-Zeldovich effect

Context. In cosmological fits, it is common to fix the baryon density ωb via the cosmic microwave background. We here constrain ωb by means of a model-independent interpolation of the acoustic parameter from correlated baryonic acoustic oscillations. Aims. The proposed technique is used to alleviate the degeneracy between baryonic and dark matter abundances. Methods. We propose a model-independent Bézier parametric interpolation and applied it to intermediate-redshift data. We first interpolated the observational Hubble data to extract cosmic bounds over the (reduced) Hubble constant h0 and interpolated the angular diameter distances, D(z), of the galaxy clusters, inferred from the Sunyaev-Zeldovich effect, to constrain the spatial curvature, Ωk. Through the Hubble points and D(z) determined in this way, we interpolated uncorrelated data of baryonic acoustic oscillations bounding the baryon ωb and total matter ωm densities, reinforcing the constraints on h0 and Ωk with the same technique. Finally, to remove the matter sector degeneracy, we obtained ωb by interpolating the acoustic parameter from correlated baryonic acoustic oscillations. Results. Monte Carlo Markov chain simulations agree at 1σ confidence level with the flat ΛCDM model and are roughly suitable at 1σ with its nonflat extension, while the Hubble constant appears in tension up to the 2σ confidence levels. Conclusions. Our method excludes very small extensions of the standard cosmological model, and on the Hubble tension side, seems to match local constraints slightly.

A unified model of particle physics and cosmology: Origin of inflation, baryogenesis, neutrino mass, CDM and dark energy

I propose a unified model of particle physic and cosmology based on both a new extension of the standard particle model and the fundamental principle of the standard cosmology. Beyond the standard model, I introduce several species of dark fields with the dark symmetry of [Formula: see text], the inflation field, cold dark matter (CDM) and dark energy (DE) are of course included among them. The model can coherently and completely describe the origin and evolution of the universe from the primordial inflation to the reheating, to the baryogenesis, to the current CDM and DE, and also the neutrino mass generation mechanism. For the energy evolution of each phase, I give its dynamical system of equations, and solve them by some special techniques. The numerical results can clearly show how each evolution is successfully implemented, furthermore, the model demonstrates that the DE genesis is purely from the CDM condensation, which is essentially a reverse process of the primordial slow-roll inflation, there is not the so-called “cosmological constant energy”. By use of fewer input parameters, the model not only exactly reproduces the measured inflationary data and the current energy density budget, but also finely predicts such important values as the tensor-to-scalar ratio [Formula: see text], the inflaton mass [Formula: see text][Formula: see text]GeV, the reheating temperature [Formula: see text][Formula: see text]GeV, the CDM mass [Formula: see text][Formula: see text]GeV, [Formula: see text] and [Formula: see text], in particular, the model smoothly clarifies and eliminates the “Hubble tension”. In short, the unified model newly establishes the deeper and closer relations between particle physics and cosmology, therefore we expect the ongoing and future experiments to test the model.

Expansion and Exploration: A Deeper Look into Hubble Tension, Supernovae, and Other Stellar Mysteries (Professor Alex Filippenko)

Expansion and Exploration: A Deeper Look into Hubble Tension, Supernovae, and Other Stellar Mysteries (Professor Alex Filippenko)

Multiple measurements on the cosmic curvature using Gaussian process regression without calibration and a cosmological model

In this letter, we propose a novel cosmological model-independent method to determine cosmic curvature, combining the recent measurements of transverse and line-of-sight directions in the baryon acoustic oscillations (BAO) with cosmic chronometers (CC) datasets. Considering that the CC dataset is discrete and includes only 32 H(z) measurements, we apply Gaussian process (GP) regression to fit the CC dataset and reconstruct them. Our methodology, which does not need the calibration or selection of any cosmological model, provide multiple measurements of spatial curvature (ΩK) at different redshifts (depending on the redshift coverage of BAO dataset). For combination of all BAO data, we find that the constraint result on cosmic curvature is ΩK=−0.096−0.195+0.190 with 1σ observational uncertainty. Although the measured ΩK is in good agreement with zero cosmic curvature within 1σ confidence level, our result revels the fact of a closed universe. More importantly, our results show that the obtained ΩK measurements are almost unaffected by different priors of the Hubble constant. This could help solve the issue of the Hubble tension that may be caused by inconsistencies in the spatial curvature between the early and late universes.

Hubble tension as a window on the gravitation of the dark matter sector: Exploration of a family of models

Hubble tension as a window on the gravitation of the dark matter sector: Exploration of a family of models