Any unified early and late dark energy scenario with a single tracking scalar field requires a potential with three distinct slopes arranged in a steep-steeper-shallow hierarchy.
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A 6% measurement of the Hubble parameter at $z\sim0.45$: direct evidence of the epoch of cosmic re-acceleration
Baseline reference. 64% of citing Pith papers use this work as a benchmark or comparison.
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abstract
Deriving the expansion history of the Universe is a major goal of modern cosmology. To date, the most accurate measurements have been obtained with Type Ia Supernovae and Baryon Acoustic Oscillations, providing evidence for the existence of a transition epoch at which the expansion rate changes from decelerated to accelerated. However, these results have been obtained within the framework of specific cosmological models that must be implicitly or explicitly assumed in the measurement. It is therefore crucial to obtain measurements of the accelerated expansion of the Universe independently of assumptions on cosmological models. Here we exploit the unprecedented statistics provided by the Baryon Oscillation Spectroscopic Survey (BOSS) Data Release 9 to provide new constraints on the Hubble parameter $H(z)$ using the em cosmic chronometers approach. We extract a sample of more than 130000 of the most massive and passively evolving galaxies, obtaining five new cosmology-independent $H(z)$ measurements in the redshift range $0.3<z<0.5$, with an accuracy of $\sim$11-16\% incorporating both statistical and systematic errors. Once combined, these measurements yield a 6\% accuracy constraint of $H(z=0.4293)=91.8\pm5.3$ km/s/Mpc. The new data are crucial to provide the first cosmology-independent determination of the transition redshift at high statistical significance, measuring $z_{t}=0.4\pm0.1$, and to significantly disfavor the null hypothesis of no transition between decelerated and accelerated expansion at 99.9\% confidence level. This analysis highlights the wide potential of the cosmic chronometers approach: it permits to derive constraints on the expansion history of the Universe with results competitive with standard probes, and most importantly, being the estimates independent of the cosmological model, it can constrain cosmologies beyond -and including- the $\Lambda$CDM model.
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representative citing papers
First background-level constraints on Luciano-Saridakis entropic cosmology using CC, Pantheon+ with SH0ES, DESI DR2 BAO and compressed Planck data show robust fit, 2sigma exclusion of LambdaCDM, and potential Hubble tension alleviation.
Strong gravitational lensing data from early-type galaxies and Abell 1689 constrain three sign-changeable dark-sector interaction models, yielding negative interaction strengths larger in magnitude than prior probes and an acceleration transition at z_t ~1.8-2.1.
Latent-f and latent-H Gaussian process reconstructions from OHD data both yield f(z), w(z), and Om(z) consistent with Lambda-CDM, with no strong predictive preference and small prior-dependent residuals mainly at high redshift.
Gravitationally induced particle creation models fit cosmological data as well as ΛCDM and reduce the Hubble tension from 4.3σ to 2.4–3σ.
Extended Proca-Nuevo gravity modifies the background expansion via a vector field algebraic constraint but leaves the matter growth equation identical to general relativity.
A barotropic fluid with ω_s ≈ 0.29 and Ω_s ≈ 1.5×10^{-5} raises the inferred H0 to match SH0ES while remaining consistent with Planck CMB, DESI BAO, and Pantheon data.
Node-based reconstruction of cosmic expansion prefers stronger deceleration at z≈1.7 than smooth DE EoS parametrizations, isolating z~1.5-2 as a window where the latter may compress localized kinematic features permitted by current data.
No evidence for directional anisotropy in the cosmic distance duality relation is found, yielding a robust 95% upper bound of 0.025 on the dipole amplitude after accounting for survey selection effects.
Combining 104 FRBs with CC, SNe, and BAO data yields 10-43% tighter constraints on Omega_b, H0, and dark energy parameters in LambdaCDM, wCDM, CPL, and three f(R) models, with modest preference for extensions over LambdaCDM.
Padé cosmographic analysis with MCMC constrains VCDM parameters using chronometers, DESI BAO, and supernova datasets, showing consistency with ΛCDM and no robust transition feature.
Quadratic f(Q) gravity adds an H^4 term to the Friedmann equation and introduces a time-dependent G_eff that suppresses linear growth and halo abundance, offering a modified-gravity route to easing the S8 tension.
The JCDM model yields H0 of 66.95 plus or minus 0.51 km/s/Mpc and Omega_m of 0.3419 plus or minus 0.0065 in a flat universe, rising to H0 of 69.13 plus or minus 0.56 with slight positive curvature, fitting late-time data but struggling with full early-universe consistency.
Reconstruction of EFT background functions from cosmic chronometer Hubble data allows model-independent tests of dark energy evolution in scalar-tensor theories.
Interacting k-essence dark energy and non-pressureless dark matter models with two interaction forms are shown to reproduce major cosmological epochs and fit observations comparably to LambdaCDM while admitting late-time de Sitter attractors.
Numerical study of interacting Barrow holographic dark energy in non-flat universes with radiation, showing EoS transitions and higher fitted H0 values that may address Hubble tension.
Einstein-Cartan model with torsion and H = -α φ assumption fitted via MCMC to CC data produces H0 values of 66-69 km/s/Mpc favoring the CMB side of the Hubble tension.
The ANN-reconstructed Hubble parameter H(z) from cosmic chronometers aligns with Lambda CDM predictions within uncertainties.
EMCEE outperforms GP and MAF in recovering true H0 from mock cosmic chronometer datasets, with GP most sensitive to data points via delete-d jackknife analysis.
Updated global fit of neutrino oscillation data gives precise measurements of mixing parameters with a 2.5 sigma preference for normal mass ordering.
MCMC constraints on two Lambda(t) models with DESI DR2, CC, and Pantheon+ data yield H0 ~72.5-73 km/s/Mpc, Omega_m0 near standard values in joint fits, and n~0.3 indicating mild deviation from LambdaCDM.
citing papers explorer
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Perturbation Dynamics and Structure Formation in Extended Proca-Nuevo Gravity
Extended Proca-Nuevo gravity modifies the background expansion via a vector field algebraic constraint but leaves the matter growth equation identical to general relativity.
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Barrow holographic dark energy interacting model in the presence of radiation and matter
Numerical study of interacting Barrow holographic dark energy in non-flat universes with radiation, showing EoS transitions and higher fitted H0 values that may address Hubble tension.