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The temperature and polarization of the cosmic microwave background (CMB), as measured today, may offer key insights into the topology of the early universe prior to inflation, for example, by discriminating between flat and warped…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-29 Miguel-Angel Sanchis-Lozano

Recently, BICEP2 measurements of the cosmic microwave background (CMB) $B$-mode polarization at degree angular scales has indicated the presence of tensor modes with a high tensor-to-scalar ratio of $r=0.2$ when assuming nearly…

High Energy Physics - Phenomenology · Physics 2015-06-22 Guo-Chin Liu , Kin-Wang Ng , I-Chin Wang

I review the general aspects of cosmological parameter estimation from observations of the cosmic microwave background (CMB) temperature anisotropies in the framework of inflationary adiabatic models. The most recent CMB datasets are…

Astrophysics · Physics 2009-10-31 A. Balbi

Primordial black holes (PBHs) would induce non-Gaussianity in the cosmic microwave background (CMB) by sourcing recombination perturbations spatially modulated by relative velocities between PBHs and the baryons they accrete. The leading…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-11 Trey W. Jensen , Yacine Ali-Haïmoud

We investigate whether non-adiabatic perturbations from inflation could produce an asymmetric distribution of temperature anisotropies on large angular scales in the cosmic microwave background (CMB). We use a generalised non-linear $\delta…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-23 Hooshyar Assadullahi , Hassan Firouzjahi , Mohammad Hossein Namjoo , David Wands

The Cosmic Microwave Background (CMB) is a relict of the early universe. Its perfect 2.725K blackbody spectrum demonstrates that the universe underwent a hot, ionized early phase; its anisotropy (about 80 \mu K rms) provides strong evidence…

Instrumentation and Methods for Astrophysics · Physics 2015-06-11 Paolo de Bernardis , Silvia Masi

Primordial magnetic fields will generate non-Gaussian signals in the cosmic microwave background (CMB) as magnetic stresses and the temperature anisotropy they induce depend quadratically on the magnetic field. We compute a new measure of…

Cosmology and Nongalactic Astrophysics · Physics 2012-06-15 Pranjal Trivedi , T. R. Seshadri , Kandaswamy Subramanian

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…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-10 Stefano Gariazzo , Olga Mena , Victor Miralles , Héctor Ramírez , Lotfi Boubekeur

We evaluate the angular bispectrum of the CMB temperature anisotropy at large angular scale due to a stochastic background of primordial magnetic fields. The shape of non-Gaussianity depends on the spectral index of the magnetic field power…

Cosmology and Nongalactic Astrophysics · Physics 2009-10-02 Chiara Caprini , Fabio Finelli , Daniela Paoletti , Antonio Riotto

Detailed study of the scalar and tensor perturbation spectra can provide much information about the primordial fluctuation-generator, be it inflation or something else. The tensor perturbation spectrum may be observable through its…

Astrophysics · Physics 2007-05-23 L. Knox

Cosmic microwave background observations are most commonly analyzed by estimating the power spectrum. In the limit where the CMB statistics are perfectly Gaussian, this extracts all the information, but the CMB also contains detectable…

Cosmology and Nongalactic Astrophysics · Physics 2011-11-09 Kendrick M. Smith

The presence of non--Gaussian features in the Cosmic Microwave Background (CMB) radiation maps represents one of the most long--awaited clues in the search for the actual structure of the primordial radiation, still needing confirmation.…

Astrophysics · Physics 2009-10-22 Alejandro Gangui

The cosmic microwave background (CMB) temperature anisotropies from primordial magnetic fields are studied. In addition to the known passive and the compensated mode we discuss an inflationary magnetic mode in the curvature perturbation,…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Camille Bonvin , Chiara Caprini , Ruth Durrer

We use cosmic microwave background (CMB) data from the 9-year WMAP release to derive constraints on monodromy inflation, which is characterized by a linear inflaton potential with a periodic modulation. We identify two possible periodic…

Cosmology and Nongalactic Astrophysics · Physics 2013-10-01 Hiranya Peiris , Richard Easther , Raphael Flauger

The B-mode polarization of the cosmic microwave background (CMB) provides a unique window into tensor perturbations from inflationary gravitational waves. Survey effects complicate the estimation and description of the power spectrum on the…

Cosmology and Nongalactic Astrophysics · Physics 2016-09-28 Eric R. Switzer , Duncan J. Watts

We quantify the limiting factors in optimizing current-technology cosmic microwave background (CMB) polarization experiments in order to learn about inflationary physics. We consider space-based, balloon-borne and ground-based experiments.…

Astrophysics · Physics 2011-05-12 Licia Verde , Hiranya Peiris , Raul Jimenez

In the standard model of cosmology (SMC) the B-mode polarization of the CMB can be explained by the gravitational effects in the inflation epoch. However, this is not the only way to explain the B-mode polarization for the CMB. It can be…

High Energy Physics - Phenomenology · Physics 2016-05-31 S. Batebi , M. Haghighat , R. Mohammadi , S. Tizchang

The increasing precision of cosmological datasets is opening up new opportunities to test predictions from cosmic inflation. Here we study the impact of high precision constraints on the primordial power spectrum and show how a new…

Astrophysics · Physics 2010-04-08 Benjamin Gold , Andreas Albrecht

We calculate the spectrum of large angle cosmic microwave background (CMB) anisotropies due to quantum fluctuations of the gravitational wave modes in one-bubble open inflation models. We find the bubble-wall fluctuation modes, which had…

Astrophysics · Physics 2016-08-30 Misao Sasaki , Takahiro Tanaka , Yoshihiro Yakushige

We consider a double-inflationary model with two massive scalar fields interacting only gravitationally in the context of a flat cold dark matter (CDM) Universe. The cosmic microwave background (CMB) temperature anisotropies produced in…

Astrophysics · Physics 2009-10-30 Julien Lesgourgues , David Polarski