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Phenomenological approaches of inflation and their equivalence
Mena, Olga; Boubekeur, Lotfi; Ramírez, Héctor +1 more
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 equiva…
Detecting the cosmological neutrino background in the CMB
Sellentin, Elena; Durrer, Ruth
Three relativistic particles in addition to the photon are detected in the cosmic microwave background (CMB). In the standard model of cosmology, these are interpreted as the three neutrino species. However, at the time of CMB decoupling, neutrinos are not only relativistic but they are also free-streaming. Here we investigate whether the CMB is s…
Effects of Rayleigh scattering on the CMB and cosmic structure
Sigurdson, Kris; Alipour, Elham; Hirata, Christopher M.
During and after recombination, in addition to Thomson scattering with free electrons, photons also couple to neutral hydrogen and helium atoms through Rayleigh scattering. This coupling influences both cosmic microwave background (CMB) anisotropies and the distribution of matter in the Universe. The frequency dependence of the Rayleigh cross sect…
Gaussian approximation of peak values in the integrated Sachs-Wolfe effect
Aiola, Simone; Kosowsky, Arthur; Wang, Bingjie
The accelerating expansion of the universe at recent epochs is encoded in the cosmic microwave background: a few percent of the total temperature fluctuations are generated by evolving gravitational potentials which trace the large-scale structures in the universe. This signature of dark energy, the integrated Sachs-Wolfe effect, has been detected…
Relating the inhomogeneous power spectrum to the CMB hemispherical anisotropy
Jain, Pankaj; Rath, Pranati K.; Aluri, Pavan K.
We relate the observed hemispherical anisotropy in the cosmic microwave radiation data to an inhomogeneous power spectrum model. The hemispherical anisotropy can be parametrized in terms of the dipole modulation model. This model leads to correlations between spherical harmonic coefficients corresponding to multipoles, l and l +1 . We extract the …
Planck trispectrum constraints on primordial non-Gaussianity at cubic order
Cooray, Asantha; Smidt, Joseph; Feng, Chang +3 more
Non-Gaussianity of the primordial density perturbations provides an important measure to constrain models of inflation. At cubic order the non-Gaussianity is captured by two parameters τNL and gNL that determine the amplitude of the density perturbation trispectrum. Here we report measurements of the kurtosis power spectra of…
Testing supersymmetric Higgs inflation with non-Gaussianity
Kawai, Shinsuke; Kim, Jinsu
We investigate multifield signatures of the nonminimally coupled supersymmetric Higgs inflation-type cosmological scenario, focusing on the two-field Higgs-lepton inflation model as a concrete example. This type of inflationary model is realized in a theory beyond the Standard Model embedded in supergravity with a noncanonical Kähler potential. We…
Planck constraints on inflation in auxiliary vector modified f (R ) theories
Tsujikawa, Shinji; Ozkan, Mehmet; Pang, Yi
We show that the universal α -attractor models of inflation can be realized by including an auxiliary vector field Aµ for the Starobinsky model with the Lagrangian f (R )=R +R2/(6 M2) . If the same procedure is applied to general modified f (R ) theories in which the Ricci scalar R is replaced by R +A&mi…
Kinetically modified nonminimal chaotic inflation
Pallis, Constantinos
We consider supersymmetric (SUSY) and non-SUSY models of chaotic inflation based on the ϕn potential with 2 ≤n ≤6 . We show that the coexistence of a nonminimal coupling to gravity fR=1 +cRϕn /2 with a kinetic mixing of the form fK=cKfRm can accommodate inflati…
Constraint on noncommutative spacetime from PLANCK data
Chingangbam, Pravabati; Das, Subinoy; P. K., Joby
We constrain the energy scale of noncommutativity of spacetime using cosmic microwave background data from PLANCK. We find that PLANCK data put the lower bound on the noncommutativity energy scale to about 20 TeV, which is about a factor of 2 larger than a previous constraint that was obtained using data from WMAP, ACBAR and CBI. We further show t…