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Author |
Gariazzo, S.; Mena, O.; Miralles, V.; Ramirez, H.; Boubekeur, L. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Running of featureful primordial power spectra |
Type |
Journal Article |
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Year |
2017 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
95 |
Issue |
12 |
Pages |
123534 - 7pp |
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Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
Current measurements of the temperature and polarization anisotropy power spectra of the cosmic microwave background (CMB) seem to indicate that the naive expectation for the slow-roll hierarchy within the most simple inflationary paradigm may not be respected in nature. We show that a primordial power spectrum with localized features could in principle give rise to the observed slow-roll anarchy when fitted to a featureless power spectrum. From a model comparison perspective, and assuming that nature has chosen a featureless primordial power spectrum, we find that, while with mock Planck data there is only weak evidence against a model with localized features, upcoming CMB missions may provide compelling evidence against such a nonstandard primordial power spectrum. This evidence could be reinforced if a featureless primordial power spectrum is independently confirmed from bispectrum and/or galaxy clustering measurements. |
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Address |
[Gariazzo, Stefano; Mena, Olga; Miralles, Victor; Ramirez, Hector] Univ Valencia, CSIC, Inst Fis Corpuscular IFIC, Apartado Correos 22085, E-46071 Valencia, Spain |
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Publisher |
Amer Physical Soc |
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English |
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Series Volume |
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Edition |
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ISSN |
2470-0010 |
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Expedition |
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Conference |
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Notes |
WOS:000404475200004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3186 |
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Permanent link to this record |
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Author |
Heisenberg, L.; Ramirez, H.; Tsujikawa, S. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Inflation with mixed helicities and its observational imprint on CMB |
Type |
Journal Article |
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Year |
2019 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
99 |
Issue |
2 |
Pages |
023505 - 14pp |
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Keywords |
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Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
In the framework of effective field theories with prominent helicity-0 and helicity-1 fields coupled to each other via a dimension-3 operator, we study the dynamics of inflation driven by the helicity-0 mode, with a given potential energy, as well as the evolution of cosmological perturbations, influenced by the presence of a mixing term between both helicities. In this scenario, the temporal component of the helicity-1 mode is an auxiliary field and can be integrated out in terms of the time derivative of the helicity-0 mode, so that the background dynamics effectively reduces to that in single-field inflation modulated by a parameter beta associated to the coupling between helicity-0 and helicity-1 modes. We discuss the evolution of a longitudinal scalar perturbation psi and an inflaton fluctuation delta phi, and we explicitly show that a particular combination of these two, which corresponds to an isocurvature mode, is subject to exponential suppression by the vector mass comparable to the Hubble expansion rate during inflation. Furthermore, we find that the effective single-field description corrected by beta also holds for the power spectrum of curvature perturbations generated during inflation. We compute the standard inflationary observables such as the scalar spectral index n(s), and the tensorto-scalar ratio r and confront several inflaton potentials with the recent observational data provided by Planck 2018. Our results show that the coupling between helicity-0 and helicity-1 modes can lead to a smaller value of the tensor-to-scalar ratio especially for small-field inflationary models, so our scenario exhibits even better compatibility with the current observational data. |
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Address |
[Heisenberg, Lavinia] Swiss Fed Inst Technol, Inst Theoret Phys, Wolfgang Pauli Str 27, CH-8093 Zurich, Switzerland |
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Thesis |
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Publisher |
Amer Physical Soc |
Place of Publication |
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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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ISSN |
2470-0010 |
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Expedition |
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Conference |
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Notes |
WOS:000454769400004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3864 |
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Permanent link to this record |
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Author |
Boubekeur, L.; Giusarma, E.; Mena, O.; Ramirez, H. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Phenomenological approaches of inflation and their equivalence |
Type |
Journal Article |
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Year |
2015 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
91 |
Issue |
8 |
Pages |
083006 - 8pp |
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Keywords |
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Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
In this work, we analyze two possible alternative and model-independent approaches to describe the inflationary period. The first one assumes a general equation of state during inflation due to Mukhanov, while the second one is based on the slow-roll hierarchy suggested by Hoffman and Turner. We find that, remarkably, the two approaches are equivalent from the observational viewpoint, as they single out the same areas in the parameter space, and agree with the inflationary attractors where successful inflation occurs. Rephrased in terms of the familiar picture of a slowly rolling, canonically normalized scalar field, the resulting inflaton excursions in these two approaches are almost identical. Furthermore, once the Galactic dust polarization data from Planck are included in the numerical fits, inflaton excursions can safely take sub-Planckian values. |
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Address |
[Boubekeur, Lotfi; Mena, Olga; Ramirez, Hector] Univ Valencia, CSIC, Inst Fis Corpuscular IFIC, E-46071 Valencia, Spain |
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Thesis |
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Publisher |
Amer Physical Soc |
Place of Publication |
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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 |
1550-7998 |
ISBN |
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Expedition |
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Conference |
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Notes |
WOS:000353138800002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2196 |
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Permanent link to this record |
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Author |
Ramirez, H.; Passaglia, S.; Motohashi, H.; Hu, W.; Mena, O. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Reconciling tensor and scalar observables in G-inflation |
Type |
Journal Article |
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Year |
2018 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
04 |
Issue |
4 |
Pages |
039 - 20pp |
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Keywords |
inflation; cosmological parameters from CMBR |
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Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
The simple m(2)phi(2) potential as an inflationary model is coming under increasing tension with limits on the tensor-to-scalar ratio r and measurements of the scalar spectral index n(s). Cubic Galileon interactions in the context of the Horndeski action can potentially reconcile the observables. However, we show that this cannot be achieved with only a constant Galileon mass scale because the interactions turn off too slowly, leading also to gradient instabilities after inflation ends. Allowing for a more rapid transition can reconcile the observables but moderately breaks the slow-roll approximation leading to a relatively large and negative running of the tilt alpha(s) that can be of order n(s) – 1. We show that the observables on CMB and large scale structure scales can be predicted accurately using the optimized slow-roll approach instead of the traditional slow-roll expansion. Upper limits on vertical bar alpha(s)vertical bar place a lower bound of r greater than or similar to 0.005 and, conversely, a given r places a lower bound on vertical bar alpha(s)vertical bar, both of which are potentially observable with next generation CMB and large scale structure surveys. |
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Address |
[Ramirez, Hector] Univ Valencia, Dept Fis Teor, Dr Moliner 50, E-46100 Burjassot, Spain, Email: hector.ramirez@uv.es; |
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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 |
1475-7516 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000429895200001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3557 |
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Permanent link to this record |
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Author |
Escudero, M.; Ramirez, H.; Boubekeur, L.; Giusarma, E.; Mena, O. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
The present and future of the most favoured inflationary models after Planck 2015 |
Type |
Journal Article |
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Year |
2016 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
02 |
Issue |
2 |
Pages |
020 - 21pp |
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Keywords |
inflation; cosmological parameters from CMBR; CMBR experiments |
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Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
The value of the tensor-to-scalar ratio r in the region allowed by the latest Planck 2015 measurements can be associated to a large variety of inflationary models. We discuss here the potential of future Cosmic Microwave Background cosmological observations in disentangling among the possible theoretical scenarios allowed by our analyses of current Planck temperature and polarization data. Rather than focusing only on r, we focus as well on the running of the primordial power spectrum, alpha(s) and the running thereof, beta(s). If future cosmological measurements, as those from the COrE mission, confirm the current best-fit value for beta(s) greater than or similar to 10(-2) as the preferred one, it will be possible to rule-out the most favoured inflationary models. |
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Address |
[Escudero, Miguel; Ramirez, Hector; Boubekeur, Lotfi; Mena, Olga] Univ Valencia, CSIC, Inst Fis Corpuscular IFIC, Apartado Correos 22085, E-46071 Valencia, Spain, Email: miguel.escudero@ific.uv.es; |
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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 |
1475-7516 |
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:000372467600021 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2590 |
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Permanent link to this record |