Planck 2013 results. XXII. Constraints on inflation
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 $n_s = 0.9603 \pm 0.0073$, ruling out exact scale invariance at over 5 $\sigma$...
| Main Authors: | , , , , , , , , , , , , , , , , , , , , , , , , |
|---|---|
| Format: | Journal article |
| Language: | English |
| Published: |
EDP Sciences
2013
|
| _version_ | 1826293211322122240 |
|---|---|
| author | Collaboration, P Ade, P Aghanim, N Armitage-Caplan, C Arnaud, M Ashdown, M Atrio-Barandela, F Aumont, J Baccigalupi, C Banday, A Barreiro, R Bartlett, J Bartolo, N Battaner, E Benabed, K Benoit, A Benoit-Levy, A Bernard, J Bersanelli, M Bielewicz, P Bobin, J Bock, J Bonaldi, A Bond, JR Borrill, J |
| author_facet | Collaboration, P Ade, P Aghanim, N Armitage-Caplan, C Arnaud, M Ashdown, M Atrio-Barandela, F Aumont, J Baccigalupi, C Banday, A Barreiro, R Bartlett, J Bartolo, N Battaner, E Benabed, K Benoit, A Benoit-Levy, A Bernard, J Bersanelli, M Bielewicz, P Bobin, J Bock, J Bonaldi, A Bond, JR Borrill, J |
| author_sort | Collaboration, P |
| collection | OXFORD |
| description | 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 $n_s = 0.9603 \pm 0.0073$, ruling out exact scale invariance at over 5 $\sigma$. 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 $d n_s/d ln k = -0.0134 \pm 0.0090$. Several analyses dropping the slow-roll approximation are carried out, including detailed model comparison and inflationary potential reconstruction. We also investigate whether the primordial power spectrum contains any features. We find that models with a parameterized oscillatory feature improve the fit $\chi^2$ by ~ 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 bounds on $f_\mathrm{NL}$ measured by Planck. The fractional primordial contribution of CDM isocurvature modes in the curvaton and axion scenarios has upper bounds of 0.25% or 3.9% (95% CL), respectively. In models with arbitrarily correlated CDM or neutrino isocurvature modes, an anticorrelation can improve $\chi^2$ by approximatively 4 as a result of slightly lowering the theoretical prediction for the $\ell<40$ multipoles relative to the higher multipoles. Nonetheless, the data are consistent with adiabatic initial conditions. |
| first_indexed | 2024-03-07T03:26:36Z |
| format | Journal article |
| id | oxford-uuid:b940d335-9481-40d2-8e84-13f00907c388 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T03:26:36Z |
| publishDate | 2013 |
| publisher | EDP Sciences |
| record_format | dspace |
| spelling | oxford-uuid:b940d335-9481-40d2-8e84-13f00907c3882022-03-27T05:01:45ZPlanck 2013 results. XXII. Constraints on inflationJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:b940d335-9481-40d2-8e84-13f00907c388EnglishSymplectic Elements at OxfordEDP Sciences2013Collaboration, PAde, PAghanim, NArmitage-Caplan, CArnaud, MAshdown, MAtrio-Barandela, FAumont, JBaccigalupi, CBanday, ABarreiro, RBartlett, JBartolo, NBattaner, EBenabed, KBenoit, ABenoit-Levy, ABernard, JBersanelli, MBielewicz, PBobin, JBock, JBonaldi, ABond, JRBorrill, JWe 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 $n_s = 0.9603 \pm 0.0073$, ruling out exact scale invariance at over 5 $\sigma$. 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 $d n_s/d ln k = -0.0134 \pm 0.0090$. Several analyses dropping the slow-roll approximation are carried out, including detailed model comparison and inflationary potential reconstruction. We also investigate whether the primordial power spectrum contains any features. We find that models with a parameterized oscillatory feature improve the fit $\chi^2$ by ~ 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 bounds on $f_\mathrm{NL}$ measured by Planck. The fractional primordial contribution of CDM isocurvature modes in the curvaton and axion scenarios has upper bounds of 0.25% or 3.9% (95% CL), respectively. In models with arbitrarily correlated CDM or neutrino isocurvature modes, an anticorrelation can improve $\chi^2$ by approximatively 4 as a result of slightly lowering the theoretical prediction for the $\ell<40$ multipoles relative to the higher multipoles. Nonetheless, the data are consistent with adiabatic initial conditions. |
| spellingShingle | Collaboration, P Ade, P Aghanim, N Armitage-Caplan, C Arnaud, M Ashdown, M Atrio-Barandela, F Aumont, J Baccigalupi, C Banday, A Barreiro, R Bartlett, J Bartolo, N Battaner, E Benabed, K Benoit, A Benoit-Levy, A Bernard, J Bersanelli, M Bielewicz, P Bobin, J Bock, J Bonaldi, A Bond, JR Borrill, J Planck 2013 results. XXII. Constraints on inflation |
| title | Planck 2013 results. XXII. Constraints on inflation |
| title_full | Planck 2013 results. XXII. Constraints on inflation |
| title_fullStr | Planck 2013 results. XXII. Constraints on inflation |
| title_full_unstemmed | Planck 2013 results. XXII. Constraints on inflation |
| title_short | Planck 2013 results. XXII. Constraints on inflation |
| title_sort | planck 2013 results xxii constraints on inflation |
| work_keys_str_mv | AT collaborationp planck2013resultsxxiiconstraintsoninflation AT adep planck2013resultsxxiiconstraintsoninflation AT aghanimn planck2013resultsxxiiconstraintsoninflation AT armitagecaplanc planck2013resultsxxiiconstraintsoninflation AT arnaudm planck2013resultsxxiiconstraintsoninflation AT ashdownm planck2013resultsxxiiconstraintsoninflation AT atriobarandelaf planck2013resultsxxiiconstraintsoninflation AT aumontj planck2013resultsxxiiconstraintsoninflation AT baccigalupic planck2013resultsxxiiconstraintsoninflation AT bandaya planck2013resultsxxiiconstraintsoninflation AT barreiror planck2013resultsxxiiconstraintsoninflation AT bartlettj planck2013resultsxxiiconstraintsoninflation AT bartolon planck2013resultsxxiiconstraintsoninflation AT battanere planck2013resultsxxiiconstraintsoninflation AT benabedk planck2013resultsxxiiconstraintsoninflation AT benoita planck2013resultsxxiiconstraintsoninflation AT benoitlevya planck2013resultsxxiiconstraintsoninflation AT bernardj planck2013resultsxxiiconstraintsoninflation AT bersanellim planck2013resultsxxiiconstraintsoninflation AT bielewiczp planck2013resultsxxiiconstraintsoninflation AT bobinj planck2013resultsxxiiconstraintsoninflation AT bockj planck2013resultsxxiiconstraintsoninflation AT bonaldia planck2013resultsxxiiconstraintsoninflation AT bondjr planck2013resultsxxiiconstraintsoninflation AT borrillj planck2013resultsxxiiconstraintsoninflation |