Data di Pubblicazione:
2014
Abstract:
We analyse the implications of the Planck data for cosmic inflation. The
Planck nominal mission temperature anisotropy measurements, combined
with the WMAP large-angle polarization, constrain the scalar spectral
index to be ns = 0.9603 � 0.0073, ruling out exact
scale invariance at over 5sigma.Planck establishes an upper bound on
the tensor-to-scalar ratio of r< 0.11 (95% CL). The Planck data thus
shrink the space of allowed standard inflationary models, preferring
potentials with V''< 0. Exponential potential models, the simplest
hybrid inflationary models, and monomial potential models of degree n
>= 2 do not provide a good fit to the data. Planck does not find
statistically significant running of the scalar spectral index,
obtaining dns/ dlnk = - 0.0134 � 0.0090. We verify
these conclusions through a numerical analysis, which makes no slow-roll
approximation, and carry out a Bayesian parameter estimation and
model-selection analysis for a number of inflationary models including
monomial, natural, and hilltop potentials. For each model, we present
the Planck constraints on the parameters of the potential and explore
several possibilities for the post-inflationary entropy generation
epoch, thus obtaining nontrivial data-driven constraints. We also
present a direct reconstruction of the observable range of the inflaton
potential. Unless a quartic term is allowed in the potential, we find
results consistent with second-order slow-roll predictions. We also
investigate whether the primordial power spectrum contains any features.
We find that models with a parameterized oscillatory feature improve the
fit by Deltachi2eff ≈ 10; however, Bayesian
evidence does not prefer these models. We constrain several single-field
inflation models with generalized Lagrangians by combining power
spectrum data with Planck bounds on fNL. Planck constrains
with unprecedented accuracy the amplitude and possible correlation (with
the adiabatic mode) of non-decaying isocurvature fluctuations. The
fractional primordial contributions of cold dark matter (CDM)
isocurvature modes of the types expected in the curvaton and axion
scenarios have upper bounds of 0.25% and 3.9% (95% CL), respectively. In
models with arbitrarily correlated CDM or neutrino isocurvature modes,
an anticorrelated isocurvature component can improve the
chi2eff by approximately 4 as a result of
slightly lowering the theoretical prediction for the l ≲ 40
multipoles relative to the higher multipoles. Nonetheless, the data are
consistent with adiabatic initial conditions.
Planck nominal mission temperature anisotropy measurements, combined
with the WMAP large-angle polarization, constrain the scalar spectral
index to be ns = 0.9603 � 0.0073, ruling out exact
scale invariance at over 5sigma.Planck establishes an upper bound on
the tensor-to-scalar ratio of r< 0.11 (95% CL). The Planck data thus
shrink the space of allowed standard inflationary models, preferring
potentials with V''< 0. Exponential potential models, the simplest
hybrid inflationary models, and monomial potential models of degree n
>= 2 do not provide a good fit to the data. Planck does not find
statistically significant running of the scalar spectral index,
obtaining dns/ dlnk = - 0.0134 � 0.0090. We verify
these conclusions through a numerical analysis, which makes no slow-roll
approximation, and carry out a Bayesian parameter estimation and
model-selection analysis for a number of inflationary models including
monomial, natural, and hilltop potentials. For each model, we present
the Planck constraints on the parameters of the potential and explore
several possibilities for the post-inflationary entropy generation
epoch, thus obtaining nontrivial data-driven constraints. We also
present a direct reconstruction of the observable range of the inflaton
potential. Unless a quartic term is allowed in the potential, we find
results consistent with second-order slow-roll predictions. We also
investigate whether the primordial power spectrum contains any features.
We find that models with a parameterized oscillatory feature improve the
fit by Deltachi2eff ≈ 10; however, Bayesian
evidence does not prefer these models. We constrain several single-field
inflation models with generalized Lagrangians by combining power
spectrum data with Planck bounds on fNL. Planck constrains
with unprecedented accuracy the amplitude and possible correlation (with
the adiabatic mode) of non-decaying isocurvature fluctuations. The
fractional primordial contributions of cold dark matter (CDM)
isocurvature modes of the types expected in the curvaton and axion
scenarios have upper bounds of 0.25% and 3.9% (95% CL), respectively. In
models with arbitrarily correlated CDM or neutrino isocurvature modes,
an anticorrelated isocurvature component can improve the
chi2eff by approximately 4 as a result of
slightly lowering the theoretical prediction for the l ≲ 40
multipoles relative to the higher multipoles. Nonetheless, the data are
consistent with adiabatic initial conditions.
Tipologia CRIS:
1.1 Articolo in rivista
Keywords:
cosmic background radiation; inflation; early Universe
Elenco autori:
P., Collaboration; P. A., R.; N., Aghanim; C., Armitage Caplan; M., Arnaud; M., Ashdown; F., Atrio Barandela; J., Aumont; C., Baccigalupi; A. J., Banday; R. B., Barreiro; J. G., Bartlett; N., Bartolo; E., Battaner; K., Benabed; A., Beno�t; A., Benoit L�vy; J., Bernard; M., Bersanelli; P., Bielewicz; J., Bobin; J. J., Bock; A., Bonaldi; J. R., Bond; J., Borrill; F. R., Bouchet; M., Bridges; M., Bucher; C., Burigana; R. C., Butler; E., Calabrese; J., Cardoso; A., Catalano; A., Challinor; A., Chamballu; H. C., Chiang; L., Chiang; P. R., Christensen; S., Church; D. L., Clements; S., Colombi; L. P., L.; F., Couchot; A., Coulais; B. P., Crill; A., Curto; F., Cuttaia; L., Danese; R. D., Davies; R. J., Davis; P. d., Bernardis; A. d., Rosa; G. d., Zotti; J., Delabrouille; J., Delouis; F., D�sert; C., Dickinson; J. M., Diego; H., Dole; S., Donzelli; O., Dor�; M., Douspis; J., Dunkley; X., Dupac; G., Efstathiou; T. A., En�lin; H. K., Eriksen; F., Finelli; O., Forni; M., Frailis; E., Franceschi; S., Galeotta; K., Ganga; C., Gauthier; M., Giard; G., Giardino; Y., Giraud H�raud; J., Gonz�lez Nuevo; K. M., G�rski; S., Gratton; A., Gregorio; A., Gruppuso; J., Hamann; F. K., Hansen; D., Hanson; D., Harrison; S., Henrot Versill�; C., Hern�ndez Monteagudo; D., Herranz; S. R., Hildebrandt; E., Hivon; M., Hobson; W. A., Holmes; A., Hornstrup; W., Hovest; K. M., Huffenberger; A. H., Jaffe; T. R., Jaffe; W. C., Jones; M., Juvela; E., Keih�nen; R., Keskitalo; T. S., Kisner; R., Kneissl; J., Knoche; L., Knox; M., Kunz; H., Kurki Suonio; G., Lagache; A., L�hteenm�ki; J., Lamarre; A., Lasenby; R. J., Laureijs; C. R., Lawrence; S., Leach; J. P., Leahy; R., Leonardi; J., Lesgourgues; A., Lewis; M., Liguori; P. B., Lilje; M., Linden V�rnle; M., L�pez Caniego; P. M., Lubin; J. F., Mac�as P�rez; B., Maffei; D., Maino; N., Mandolesi; M., Maris; D. J., Marshall; P. G., Martin; E., Mart�nez Gonz�lez; S., Masi; M., Massardi; S., Matarrese; F., Matthai; P., Mazzotta; P. R., Meinhold; A., Melchiorri; L., Mendes; A., Mennella; M., Migliaccio; S., Mitra; M., Miville Desch�nes; A., Moneti; L., Montier; G., Morgante; D., Mortlock; A., Moss; D., Munshi; J. A., Murphy; P., Naselsky; F., Nati; P., Natoli; C. B., Netterfield; H. U., N�rgaard Nielsen; F., Noviello; D., Novikov; I., Novikov; I. J., O'Dwyer; S., Osborne; C. A., Oxborrow; F., Paci; L., Pagano; F., Pajot; R., Paladini; S., Pandolfi; D., Paoletti; B., Partridge; F., Pasian; G., Patanchon; H. V., Peiris; O., Perdereau; L., Perotto; F., Perrotta; F., Piacentini; M., Piat; E., Pierpaoli; D., Pietrobon; S., Plaszczynski; E., Pointecouteau; G., Polenta; N., Ponthieu; L., Popa; T., Poutanen; G. W., Pratt; G., Pr�zeau; S., Prunet; J., Puget; J. P., Rachen; R., Rebolo; M., Reinecke; M., Remazeilles; C., Renault; S., Ricciardi; T., Riller; I., Ristorcelli; G., Rocha; C., Rosset; G., Roudier; M., Rowan Robinson; Mart�n, J. A. Rubi�o.; B., Rusholme; M., Sandri; D., Santos; M., Savelainen; G., Savini; D., Scott; M. D., Seiffert; E. P., S.; L. D., Spencer; J., Starck; V., Stolyarov; R., Stompor; R., Sudiwala; R., Sunyaev; F., Sureau; D., Sutton; A., Suur Uski; J., Sygnet; J. A., Tauber; D., Tavagnacco; Terenzi, Luca; L., Toffolatti; M., Tomasi; J., Tr�guer Goudineau; M., Tristram; M., Tucci; J., Tuovinen; L., Valenziano; J., Valiviita; B. V., Tent; J., Varis; P., Vielva; F., Villa; N., Vittorio; L. A., Wade; B. D., Wandelt; M., White; A., Wilkinson; D., Yvon; A., Zacchei; J. P., Zibin; A., Zonca
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