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Author Di Valentino, E.; Mena, O.; Pan, S.; Visinelli, L.; Yang, W.Q.; Melchiorri, A.; Mota, D.F.; Riess, A.G.; Silk, J.
Title In the realm of the Hubble tension – a review of solutions Type Journal Article
Year 2021 Publication Classical and Quantum Gravity Abbreviated Journal Class. Quantum Gravity
Volume 38 Issue 15 Pages (down) 153001 - 110pp
Keywords cosmological parameters; cosmology; dark energy; Hubble constant
Abstract The simplest ΛCDM model provides a good fit to a large span of cosmological data but harbors large areas of phenomenology and ignorance. With the improvement of the number and the accuracy of observations, discrepancies among key cosmological parameters of the model have emerged. The most statistically significant tension is the 4 sigma to 6 sigma disagreement between predictions of the Hubble constant, H (0), made by the early time probes in concert with the 'vanilla' ΛCDM cosmological model, and a number of late time, model-independent determinations of H (0) from local measurements of distances and redshifts. The high precision and consistency of the data at both ends present strong challenges to the possible solution space and demands a hypothesis with enough rigor to explain multiple observations-whether these invoke new physics, unexpected large-scale structures or multiple, unrelated errors. A thorough review of the problem including a discussion of recent Hubble constant estimates and a summary of the proposed theoretical solutions is presented here. We include more than 1000 references, indicating that the interest in this area has grown considerably just during the last few years. We classify the many proposals to resolve the tension in these categories: early dark energy, late dark energy, dark energy models with 6 degrees of freedom and their extensions, models with extra relativistic degrees of freedom, models with extra interactions, unified cosmologies, modified gravity, inflationary models, modified recombination history, physics of the critical phenomena, and alternative proposals. Some are formally successful, improving the fit to the data in light of their additional degrees of freedom, restoring agreement within 1-2 sigma between Planck 2018, using the cosmic microwave background power spectra data, baryon acoustic oscillations, Pantheon SN data, and R20, the latest SH0ES Team Riess, et al (2021 Astrophys. J. 908 L6) measurement of the Hubble constant (H (0) = 73.2 +/- 1.3 km s(-1) Mpc(-1) at 68% confidence level). However, there are many more unsuccessful models which leave the discrepancy well above the 3 sigma disagreement level. In many cases, reduced tension comes not simply from a change in the value of H (0) but also due to an increase in its uncertainty due to degeneracy with additional physics, complicating the picture and pointing to the need for additional probes. While no specific proposal makes a strong case for being highly likely or far better than all others, solutions involving early or dynamical dark energy, neutrino interactions, interacting cosmologies, primordial magnetic fields, and modified gravity provide the best options until a better alternative comes along.
Address [Di Valentino, Eleonora] Univ Durham, Inst Particle Phys Phenomenol, Dept Phys, Durham DH1 3LE, England, Email: eleonora.di-valentino@durham.ac.uk
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0264-9381 ISBN Medium
Area Expedition Conference
Notes WOS:000672148200001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4931
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Author Ghedini, P.; Hajjar, R.; Mena, O.
Title Dark energy and neutrinos along the cosmic expansion history Type Journal Article
Year 2026 Publication Physics of the Dark Universe Abbreviated Journal Phys. Dark Universe
Volume 52 Issue Pages (down) 102237 - 20pp
Keywords Dark energy; Neutrinos; Cosmological tensions
Abstract Recent cosmological measurements are hinting that dark energy may evolve, with its equation of state, wDE, even showing oscillatory patterns. In this work, we employ a model-independent approach to jointly reconstruct wDE and the sum of neutrino masses, & sum;m, adopting the Piecewise Cubic Hermite Interpolating Polynomial (PCHIP) method with seven fixed nodes in which we allow the two parameters to vary. We employ CMB, Baryon Acoustic Oscillations and Supernovae Ia data to constrain the values of wDE and & sum;m at each node. We conduct three different analyses in which we reconstruct wDE: one with fixed & sum;m = 0.06 eV; one in which we allow & sum;m to vary, and one in which we also reconstruct & sum;m using the PCHIP method. We find the dark energy equation of state to be consistent with the cosmological constant scenario, except when including DESI data and allowing for phantom crossing, where we find a 95% CL deviation from wDE = -1 around z similar to 1.2. For neutrino masses, we obtain looser constraints when focusing on phantom dark energy, that show further early and late relaxation when reconstructing the mass via the PCHIP method.
Address [Ghedini, Pietro] Univ Valencia, Dept Fis Teor, Burjassot 46100, Spain, Email: pietro.ghedini@ific.uv.es;
Corporate Author Thesis
Publisher Elsevier Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes WOS:001704433500001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 7116
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Author Artola, M.; Ayuso, I.; Lazkoz, R.; Olmo, G.; Salzano, V.
Title Geometric acceleration in f (Q, C) theories Type Journal Article
Year 2025 Publication Physics of the Dark Universe Abbreviated Journal Phys. Dark Universe
Volume 50 Issue Pages (down) 102180 - 6pp
Keywords Mofied theories of gravity; Non-metricity; Dark energy models; Observational constraints
Abstract The f(Q,C) framework of gravity enables the depiction of an effective dark energy fluid that emerges from geometry itself, thus leading to modifications in the cosmological phenomenology of General Relativity. We pursue this approach to discover new and observationally supported (effective) evolving dark energy models. We propose a general f (Q, C) formulation that cannot be simply split into separate functions of Q and C, yet it still results in second-order field equations. By employing a particular type of connection, we derive guidelines for new cosmological models, including a variant of the DGP model that appears to be statistically favored over Lambda CDM. Notably, we also demonstrate how to translate solutions within this f (Q, C) framework to f (Q) counterparts at the background level.
Address [Artola, Mikel; Ayuso, Ismael; Lazkoz, Ruth] Univ Basque Country, Dept Phys, Leioa 48940, Spain, Email: mikel.artola@ehu.eus;
Corporate Author Thesis
Publisher Elsevier Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes WOS:001631722400003 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 6968
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Author Ghedini, P.; Hajjar, R.; Mena, O.
Title Redshift-space distortions corner interacting dark energy Type Journal Article
Year 2024 Publication Physics of the Dark Universe Abbreviated Journal Phys. Dark Universe
Volume 46 Issue Pages (down) 101671 - 10pp
Keywords Dark energy; Dark matter; Dark sector interactions; Dark energy properties
Abstract Despite the fact that the Lambda CDM model has been highly successful over the last few decades in providing an accurate fit to a broad range of cosmological and astrophysical observations, different intriguing tensions and anomalies emerged at various statistical levels. Given the fact that the dark energy and the dark matter sectors remain unexplored, the answer to some of the tensions may rely on modifications of these two dark sectors. This manuscript explores the important role of the growth of structure in constraining non-standard cosmologies. In particular, we focus on the interacting dark energy (IDE) scenario, where dark matter and dark energy interact non-gravitationally. We aim to place constraints on the phenomenological parameters of these alternative models, by considering different datasets related to a number of cosmological measurements, to achieve a complementary analysis. A special emphasis is devoted to redshift-space distortion measurements (RSD), whose role in constraining beyond the standard paradigm models has not been recently highlighted. These observations indeed have a strong constraining power, rendering all parameters to their Lambda CDM canonical values, and therefore leaving little room for the IDE models explored here.
Address [Ghedini, Pietro] Univ Bologna, Dipartimento Fis & Astron, Via Irnerio 46, I-40126 Bologna, Italy, Email: pietro.ghedini3@studio.unibo.it;
Corporate Author Thesis
Publisher Elsevier Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes WOS:001333958300001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 6298
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Author Wang, D.
Title Model-independent traversable wormholes from baryon acoustic oscillations Type Journal Article
Year 2023 Publication Physics of the Dark Universe Abbreviated Journal Phys. Dark Universe
Volume 42 Issue Pages (down) 101306 - 8pp
Keywords Traversable wormholes; Dark energy; Baryon acoustic oscillations
Abstract In this paper, we investigate the model-independent traversable wormholes from baryon acoustic oscillations. Firstly, we place the statistical constraints on the average dark energy equation of state Wav by only using BAO data. Subsequently, two specific wormhole solutions are obtained, i.e, the cases of the constant redshift function and a special choice for the shape function. For the first case, we analyze the traversabilities of the wormhole configuration, and for the second case, we find that one can construct theoretically a traversable wormhole with infinitesimal amounts of average null energy condition violating phantom fluid. Furthermore, we perform the stability analysis for the first case, and find that the stable equilibrium configurations may increase for increasing values of the throat radius of the wormhole in the cases of a positive and a negative surface energy density. It is worth noting that the obtained wormhole solutions are static and spherically symmetrical metric, and that we assume Wav to be a constant between different redshifts when placing constraints, hence, these wormhole solutions can be interpreted as stable and static phantom wormholes configurations at some certain redshift which lies in the range [0.32, 2.34].
Address [Wang, Deng] Univ Valencia, Inst Fis Corpuscular, CSIC, E-46980 Paterna, Spain, Email: cstar@nao.cas.cn
Corporate Author Thesis
Publisher Elsevier Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes WOS:001122744700001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5853
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Author Di Valentino, E.; Melchiorri, A.; Mena, O.; Vagnozzi, S.
Title Interacting dark energy in the early 2020s: A promising solution to the H-0 and cosmic shear tensions Type Journal Article
Year 2020 Publication Physics of the Dark Universe Abbreviated Journal Phys. Dark Universe
Volume 30 Issue Pages (down) 100666 - 12pp
Keywords Hubble tension; Cosmological parameters; Dark matter; Dark energy; Interacting dark energy
Abstract We examine interactions between dark matter and dark energy in light of the latest cosmological observations, focusing on a specific model with coupling proportional to the dark energy density. Our data includes Cosmic Microwave Background (CMB) measurements from the Planck 2018 legacy data release, late-time measurements of the expansion history from Baryon Acoustic Oscillations (BAO) and Supernovae Type Ia (SNeIa), galaxy clustering and cosmic shear measurements from the Dark Energy Survey Year 1 results, and the 2019 local distance ladder measurement of the Hubble constant H-0 from the Hubble Space Telescope. Considering Planck data both in combination with BAO or SNeIa data reduces the H-0 tension to a level which could possibly be compatible with a statistical fluctuation. The very same model also significantly reduces the Omega(m) – sigma(8) tension between CMB and cosmic shear measurements. Interactions between the dark sectors of our Universe remain therefore a promising joint solution to these persisting cosmological tensions.
Address [Di Valentino, Eleonora] Univ Manchester, Jodrell Bank, Ctr Astrophys, Manchester M13 9PL, Lancs, England, Email: eleonora.divalentino@manchester.ac.uk;
Corporate Author Thesis
Publisher Elsevier Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2212-6864 ISBN Medium
Area Expedition Conference
Notes WOS:000595300400037 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4646
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Author Anderson, L. et al; de Putter, R.; Mena, O.
Title The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: baryon acoustic oscillations in the Data Release 9 spectroscopic galaxy sample Type Journal Article
Year 2012 Publication Monthly Notices of the Royal Astronomical Society Abbreviated Journal Mon. Not. Roy. Astron. Soc.
Volume 427 Issue 4 Pages (down) 3435-3467
Keywords cosmological parameters; cosmology: observations; dark energy; distance scale; large-scale structure of Universe
Abstract We present measurements of galaxy clustering from the Baryon Oscillation Spectroscopic Survey (BOSS), which is part of the Sloan Digital Sky Survey III (SDSS-III). These use the Data Release 9 (DR9) CMASS sample, which contains 264 283 massive galaxies covering 3275 square degrees with an effective redshift z = 0.57 and redshift range 0.43 < z < 0.7. Assuming a concordance Lambda CDM cosmological model, this sample covers an effective volume of 2.2 Gpc(3), and represents the largest sample of the Universe ever surveyed at this density, (n) over bar approximate to 3 x 10(-4) h(-3) Mpc(3). We measure the angle-averaged galaxy correlation function and power spectrum, including density-field reconstruction of the baryon acoustic oscillation (BAO) feature. The acoustic features are detected at a significance of 5 sigma in both the correlation function and power spectrum. Combining with the SDSS-II luminous red galaxy sample, the detection significance increases to 6.7 sigma. Fitting for the position of the acoustic features measures the distance to z = 0.57 relative to the sound horizon D-V/r(s) = 13.67 +/ 0.22 at z = 0.57. Assuming a fiducial sound horizon of 153.19 Mpc, which matches cosmic microwave background constraints, this corresponds to a distance D-V (z = 0.57) = 2094 +/- 34 Mpc. At 1.7 per cent, this is the most precise distance constraint ever obtained from a galaxy survey. We place this result alongside previous BAO measurements in a cosmological distance ladder and find excellent agreement with the current supernova measurements. We use these distance measurements to constrain various cosmological models, finding continuing support for a flat Universe with a cosmological constant.
Address [Anderson, Lauren] Univ Washington, Dept Astron, Seattle, WA 98195 USA, Email: nikhil.padmanabhan@yale.edu;
Corporate Author Thesis
Publisher Oxford Univ Press Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0035-8711 ISBN Medium
Area Expedition Conference
Notes WOS:000314421000014 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1319
Permanent link to this record
 

 
Author Panotopoulos, G.
Title A dynamical dark energy model with a given luminosity distance Type Journal Article
Year 2011 Publication General Relativity and Gravitation Abbreviated Journal Gen. Relativ. Gravit.
Volume 43 Issue 11 Pages (down) 3191-3199
Keywords Dark energy; Observational cosmology; Particle-theory
Abstract It is assumed that the current cosmic acceleration is driven by a scalar field, the Lagrangian of which is a function of the kinetic term only, and that the luminosity distance is a given function of the red-shift. Upon comparison with baryon acoustic oscillations and cosmic microwave background data the parameters of the models are determined, and then the time evolution of the scalar field is determined by the dynamics using the cosmological equations. We find that the solution is very different than the corresponding solution when the non-relativistic matter is ignored, and that the universe enters the acceleration era at larger red-shift compared to the standard I > CDM model.
Address [Panotopoulos, G] Univ Valencia, Dept Fis Teor, E-46100 Burjassot, Spain, Email: Grigoris.Panotopoulos@uv.es
Corporate Author Thesis
Publisher Springer/Plenum Publishers Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0001-7701 ISBN Medium
Area Expedition Conference
Notes WOS:000295982800015 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ elepoucu @ Serial 782
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Author Vagnozzi, S.; Visinelli, L.; Mena, O.; Mota, D.F.
Title Do we have any hope of detecting scattering between dark energy and baryons through cosmology? Type Journal Article
Year 2020 Publication Monthly Notices of the Royal Astronomical Society Abbreviated Journal Mon. Not. Roy. Astron. Soc.
Volume 493 Issue 1 Pages (down) 1139-1152
Keywords cosmic background radiation; cosmological parameters; cosm logy: observations; dark energy; large-scale structure of Universe
Abstract We consider the possibility that dark energy and baryons might scatter off each other. The type of interaction we consider leads to a pure momentum exchange, and does not affect the background evolution of the expansion history. We parametrize this interaction in an effective way at the level of Boltzmann equations. We compute the effect of dark energy-baryon scattering on cosmological observables, focusing on the cosmic microwave background (CMB) temperature anisotropy power spectrum and the matter power spectrum. Surprisingly, we find that even huge dark energy-baryon cross-sections sigma(xb) similar to O(b), which are generically excluded by non-cosmological probes such as collider searches or precision gravity tests, only leave an insignificant imprint on the observables considered. In the case of the CMB temperature power spectrum, the only imprint consists in a sub-per cent enhancement or depletion of power (depending whether or not the dark energy equation of state lies above or below -1) at very low multipoles, which is thus swamped by cosmic variance. These effects are explained in terms of differences in how gravitational potentials decay in the presence of a dark energy-baryon scattering, which ultimately lead to an increase or decrease in the late-time integrated Sachs-Wolfe power. Even smaller related effects are imprinted on the matter power spectrum. The imprints on the CMB are not expected to be degenerate with the effects due to altering the dark energy sound speed. We conclude that, while strongly appealing, the prospects for a direct detection of dark energy through cosmology do not seem feasible when considering realistic dark energy-baryon cross-sections. As a caveat, our results hold to linear order in perturbation theory.
Address [Vagnozzi, Sunny] Univ Cambridge, Kat Inst Cosmol, Madingley Rd, Cambridge CB3 0HA, England, Email: sunny.vagnozzi@ast.cam.ac.uk
Corporate Author Thesis
Publisher Oxford Univ Press Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0035-8711 ISBN Medium
Area Expedition Conference
Notes WOS:000518156100081 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4320
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Author Olmo, G.J.
Title Palatini approach to modified gravity: f(R) theories and beyond Type Journal Article
Year 2011 Publication International Journal of Modern Physics D Abbreviated Journal Int. J. Mod. Phys. D
Volume 20 Issue 4 Pages (down) 413-462
Keywords Palatini formalism; modified gravity; cosmic speed-up; dark energy; dark matter; MOND; quantum gravity phenomenology; Hamiltonian formulation; stellar structure; Cauchy problem; solar system tests
Abstract We review the recent literature on modified theories of gravity in the Palatini approach. After discussing the motivations that lead to consider alternatives to Einstein's theory and to treat the metric and the connection as independent objects, we review several topics that have been recently studied within this framework. In particular, we provide an in-depth analysis of the cosmic speed-up problem, laboratory and solar system tests, the structure of stellar objects, the Cauchy problem, and bouncing cosmologies. We also discuss the importance of going beyond the f(R) models to capture other phenomenological aspects related with dark matter/energy and quantum gravity.
Address [Olmo, Gonzalo J.] Univ Valencia CSIC, Dept Fis Teor, Valencia, Spain, Email: gonzalo.olmo@uv.es
Corporate Author Thesis
Publisher World Scientific Publ Co Pte Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0218-2718 ISBN Medium
Area Expedition Conference
Notes WOS:000290228200001 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 961
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