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Classicality of primordial fluctuations and Primordial Black Holes 
Auteur(s): Polarski D.
(Article) Publié:
International Journal Of Modern Physics D, vol. 10 p.927-934 (2001)
Texte intégral en Openaccess : 
Ref HAL: hal-00176706_v1
Ref Arxiv: astro-ph/0109388
DOI: 10.1142/S021827180100161X
WoS: 000173439600019
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
7 Citations
Résumé: The production of Primordial Black Holes (PBH) from inflationary perturbations provides a physical process where the effective classicality of the fluctuations does not hold for certain scales. For adiabatic perturbations produced during inflation, this range of scales corresponds to PBH with masses $M\ll 10^{15}$ g. For PBH with masses $M\sim M_H(t_e)$, the horizon mass at the end of inflation, the generation process during the preheating stage could be classical as well, in contrast to the formation of PBH on these scales by adiabatic inflationary perturbations. For the non evaporated PBH, the generation process is essentially classical.
Commentaires: uses LaTeX, 8 pages; one ref. added;
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Accelerated Expansion: Theory & Observations
Auteur(s): Polarski D.
(Article) Publié:
Journal Of Low Temperature Physics, vol. 124 p.17-24 (2001)
Texte intégral en Openaccess :
Ref Arxiv: astro-ph/0109349
DOI: 10.1023/A:1017509430993
WoS: 000170496900003
Ref. & Cit.: NASA ADS
1 Citation
Résumé: The present paradigm in cosmology is the usual Big-Bang Cosmology in which two stages of accelerated expansion are incorporated: the inflationary phase in the very early universe which produces the classical inhomogeneities observed in the universe, and a second stage of acceleration at the present time as the latest Supernovae observations seem to imply. Both stages could be produced by a scalar field and observations will strongly constrain the microscopic lagrangian of any proposed model.
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Scalar Tensor Gravity in an Accelerating Universe
Auteur(s): Esposito-Farese G., Polarski D.
(Article) Publié:
Physical Review D, vol. 63 p.063504 (2001)
Texte intégral en Openaccess :
Ref Arxiv: gr-qc/0009034
DOI: 10.1103/PhysRevD.63.063504
WoS: 000167500000012
Ref. & Cit.: NASA ADS
344 Citations
Résumé: We consider scalar-tensor theories of gravity in an accelerating universe. The equations for the background evolution and the perturbations are given in full generality for any parametrization of the Lagrangian, and we stress that apparent singularities are sometimes artifacts of a pathological choice of variables. Adopting a phenomenological viewpoint, i.e., from the observations back to the theory, we show that the knowledge of the luminosity distance as a function of redshift up to z ~ (1-2), which is expected in the near future, severely constrains the viable subclasses of scalar-tensor theories. This is due to the requirement of positive energy for both the graviton and the scalar partner. Assuming a particular form for the Hubble diagram, consistent with present experimental data, we reconstruct the microscopic Lagrangian for various scalar-tensor models, and find that the most natural ones are obtained if the universe is (marginally) closed.
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Gravitational Wave Background in Inflationary Models
Auteur(s): Polarski D.
(Article) Publié:
Aip Conference Proceedings, vol. 555 p.495-498 (2001)
DOI: 10.1063/1.1363569
Résumé: The generation of a gravitational wave (GW) background is a generic feature of inflationary models. This background, of quantum origin, covers a huge range of frequencies and is undistinguishable today on large cosmological scales from a classical stochastic background. We review some of its properties in different models including more sophisticated Broken Scale Invariance (BSI) models.
Commentaires: Cosmology and Particle Physics: CAPP 2000
AIP Conference Proceedings 555.
R.Durrer, J.Garcia-Bellido, M.Shaposhnikov Eds.
Cosmology and Particle Physics: CAPP 2000,
Verbier (Switzerland), 17-28 July 2000
ISBN: 1563969866
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Constraints on Scalar-tensor Theories in an Accelerating Universe
Auteur(s): Polarski D.
(Article) Publié:
Aip Conference Proceedings, vol. 555 p.551-554 (2001)
DOI: 10.1063/1.1363580
Résumé: We consider a presently accelerating universe in the framework of a scalar-tensor theory of gravity. We show how one can reconstruct the full theory namely, the field potential and the functional form of the scalar-gravity coupling along with the present density of dustlike matter using the following cosmological observations: luminosity distance data and linear dustlike matter density fluctuations data, both as functions of redshift. On the other hand luminosity distance observations on their own provide powerful constraints on classes of scalar-tensor theories.
Commentaires: Cosmology and Particle Physics: CAPP 2000
AIP Conference Proceedings 555 (2001)
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