| Records |
| Author |
Basilakos, S.; Mavromatos, N.E.; Mitsou, V.A.; Plionis, M. |
| Title |
Dynamics and constraints of the dissipative Liouville cosmology |
Type |
Journal Article |
| Year |
2012 |
Publication |
Astroparticle Physics |
Abbreviated Journal |
Astropart Phys. |
| Volume |
36 |
Issue |
1 |
Pages |
7-17 |
| Keywords |
Cosmology; Dark matter; Dark energy |
| Abstract |
In this article we investigate the properties of the FLRW flat cosmological models in which the cosmic expansion of the Universe is affected by a dilaton dark energy (Liouville scenario). In particular, we perform a detailed study of these models in the light of the latest cosmological data, which serves to illustrate the phenomenological viability of the new dark energy paradigm as a serious alternative to the traditional scalar field approaches. By performing a joint likelihood analysis of the recent supernovae type la data (SNIa), the differential ages of passively evolving galaxies, and the baryonic acoustic oscillations (BAOs) traced by the Sloan Digital Sky Survey (SDSS), we put tight constraints on the main cosmological parameters. Furthermore, we study the linear matter fluctuation field of the above Liouville cosmological models. In this framework, we compare the observed growth rate of clustering measured from the optical galaxies with those predicted by the current Liouville models. Performing various statistical tests we show that the Liouville cosmological model provides growth rates that match well with the observed growth rate. To further test the viability of the models under study, we use the Press-Schechter formalism to derive their expected redshift distribution of cluster-size halos that will be provided by future X-ray and Sunyaev-Zeldovich cluster surveys. We find that the Hubble flow differences between the Liouville and the LambdaCDM models provide a significantly different halo redshift distribution, suggesting that the models can be observationally distinguished. |
| Address |
[Mitsou, Vasiliki A.] Univ Valencia, CSIC, Inst Fis Corpuscular IFIC, E-46071 Valencia, Spain, Email: vasiliki.mitsou@ific.uv.es |
| Corporate Author |
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Thesis |
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| Publisher |
Elsevier Science Bv |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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ISSN  |
0927-6505 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000309787000002 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
1188 |
| Permanent link to this record |
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| Author |
Olmo, G.J.; Rubiera-Garcia, D. |
| Title |
Brane-world and loop cosmology from a gravity-matter coupling perspective |
Type |
Journal Article |
| Year |
2015 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
| Volume |
740 |
Issue |
|
Pages |
73-79 |
| Keywords |
Modified gravity; Palatini formalism; f(R) theories; Gravity-matter coupling; Quadratic cosmology |
| Abstract |
We show that the effective brane-world and the loop quantum cosmology background expansion histories can be reproduced from a modified gravity perspective in terms of an f (R) gravity action plus a g(R) term non-minimally coupled with the matter Lagrangian. The reconstruction algorithm that we provide depends on a free function of the matter density that must be specified in each case and allows to obtain analytical solutions always. In the simplest cases, the function f (R) is quadratic in the Ricci scalar, R, whereas g(R) is linear. Our approach is compared with recent results in the literature. We show that working in the Palatini formalism there is no need to impose any constraint that keeps the equations second order, which is a key requirement for the successful implementation of the reconstruction algorithm. |
| Address |
[Olmo, Gonzalo J.] Univ Valencia, CSIC, Ctr Mixto, Dept Fis Teor, E-46100 Valencia, Spain, Email: gonzalo.olmo@csic.es; |
| Corporate Author |
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Thesis |
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| Publisher |
Elsevier Science Bv |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0370-2693 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000347046200013 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
2099 |
| Permanent link to this record |
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| Author |
de Salas, P.F.; Gariazzo, S.; Martinez-Mirave, P.; Pastor, S.; Tortola, M. |
| Title |
Cosmological radiation density with non-standard neutrino-electron interactions |
Type |
Journal Article |
| Year |
2021 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
| Volume |
820 |
Issue |
|
Pages |
136508 - 9pp |
| Keywords |
Neutrino interactions; Non-standard neutrino interactions; Cosmology; Neutrino oscillations |
| Abstract |
Neutrino non-standard interactions (NSI) with electrons are known to alter the picture of neutrino de coupling from the cosmic plasma. NSI modify both flavour oscillations through matter effects, and the annihilation and scattering between neutrinos and electrons and positrons in the thermal plasma. In view of the forthcoming cosmological observations, we perform a precision study of the impact of non universal and flavour-changing NSI on the effective number of neutrinos, Neff. We present the variation of Neff arising from the different NSI parameters and discuss the existing degeneracies among them, from cosmology alone and in relation to the current bounds from terrestrial experiments. Even though cosmology is generally less sensitive to NSI than these experiments, we find that future cosmological data would provide competitive and complementary constraints for some of the couplings and their combinations. |
| Address |
[de Salas, Pablo F.] Stockholm Univ, Dept Phys, Oskar Klein Ctr Cosmoparticle Phys, SE-10691 Stockholm, Sweden, Email: pablo.fernandez@fysik.su.se; |
| Corporate Author |
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Thesis |
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| Publisher |
Elsevier |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0370-2693 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000713101800031 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5023 |
| Permanent link to this record |
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| Author |
Beltran Jimenez, J.; Heisenberg, L.; Olmo, G.J.; Rubiera-Garcia, D. |
| Title |
Born-Infeld inspired modifications of gravity |
Type |
Journal Article |
| Year |
2018 |
Publication |
Physics Reports |
Abbreviated Journal |
Phys. Rep. |
| Volume |
727 |
Issue |
|
Pages |
1-129 |
| Keywords |
Born-Infeld gravity; Astrophysics; Black holes; Cosmology; Early universe; Compact objects; Singularities |
| Abstract |
General Relativity has shown an outstanding observational success in the scales where it has been directly tested. However, modifications have been intensively explored in the regimes where it seems either incomplete or signals its own limit of validity. In particular, the breakdown of unitarity near the Planck scale strongly suggests that General Relativity needs to be modified at high energies and quantum gravity effects are expected to be important. This is related to the existence of spacetime singularities when the solutions of General Relativity are extrapolated to regimes where curvatures are large. In this sense, Born-Infeld inspired modifications of gravity have shown an extraordinary ability to regularise the gravitational dynamics, leading to non-singular cosmologies and regular black hole spacetimes in a very robust manner and without resorting to quantum gravity effects. This has boosted the interest in these theories in applications to stellar structure, compact objects, inflationary scenarios, cosmological singularities, and black hole and wormhole physics, among others. We review the motivations, various formulations, and main results achieved within these theories, including their observational viability, and provide an overview of current open problems and future research opportunities. |
| Address |
[Beltran Jimenez, Jose] Univ Autonoma Madrid, CSIC, Inst Fis Teor, E-28049 Madrid, Spain, Email: jose.beltran@uam.es; |
| Corporate Author |
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Thesis |
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| Publisher |
Elsevier Science Bv |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0370-1573 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000425482900001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
3497 |
| Permanent link to this record |
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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 |
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 |
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Thesis |
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| Publisher |
Iop Publishing Ltd |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0264-9381 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000672148200001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
4931 |
| Permanent link to this record |
