Search Publications
Detection of B-Mode Polarization at Degree Angular Scales by BICEP2
Ade, P. A. R.; Bock, J. J.; Hildebrandt, S. R. +45 more
We report results from the BICEP2 experiment, a cosmic microwave background (CMB) polarimeter specifically designed to search for the signal of inflationary gravitational waves in the B-mode power spectrum around ℓ∼80. The telescope comprised a 26 cm aperture all-cold refracting optical system equipped with a focal plane of 512 antenna coupled tra…
Indications of a Late-Time Interaction in the Dark Sector
Melchiorri, Alessandro; Said, Najla; Salvatelli, Valentina +2 more
We show that a general late-time interaction between cold dark matter and vacuum energy is favored by current cosmological data sets. We characterize the strength of the coupling by a dimensionless parameter qV that is free to take different values in four redshift bins from the primordial epoch up to today. This interacting scenario is…
Evidence for Massive Neutrinos from Cosmic Microwave Background and Lensing Observations
Battye, Richard A.; Moss, Adam
We discuss whether massive neutrinos (either active or sterile) can reconcile some of the tensions within cosmological data that have been brought into focus by the recently released Planck data. We point out that a discrepancy is present when comparing the primary CMB and lensing measurements both from the CMB and galaxy lensing data using CFHTLe…
Neutrinos Help Reconcile Planck Measurements with the Local Universe
Hu, Wayne; Wyman, Mark; Rudd, Douglas H. +1 more
Current measurements of the low and high redshift Universe are in tension if we restrict ourselves to the standard six-parameter model of flat ΛCDM. This tension has two parts. First, the Planck satellite data suggest a higher normalization of matter perturbations than local measurements of galaxy clusters. Second, the expansion rate of the Univer…
Cosmological Constraints on Brans-Dicke Theory
Avilez, A.; Skordis, C.
We report strong cosmological constraints on the Brans-Dicke (BD) theory of gravity using cosmic microwave background data from Planck. We consider two types of models. First, the initial condition of the scalar field is fixed to give the same effective gravitational strength Geff today as the one measured on Earth, GN. In th…
Inflation with Whip-Shaped Suppressed Scalar Power Spectra
Starobinsky, Alexei A.; Hazra, Dhiraj Kumar; Smoot, George F. +1 more
Motivated by the idea that inflation occurs at the grand unified theory symmetry breaking scale, in this Letter we construct a new class of large field inflaton potentials where the inflaton starts with a power law potential; after an initial period of relatively fast roll that lasts until after a few e folds inside the horizon it transits to the …
Standard Rulers, Candles, and Clocks from the Low-Redshift Universe
Verde, Licia; Jimenez, Raul; Heavens, Alan
We measure the length of the baryon acoustic oscillation (BAO) feature, and the expansion rate of the recent Universe, from low-redshift data only, almost model independently. We make only the following minimal assumptions: homogeneity and isotropy, a metric theory of gravity, a smooth expansion history, and the existence of standard candles (supe…
No New Cosmological Concordance with Massive Sterile Neutrinos
Leistedt, Boris; Peiris, Hiranya V.; Verde, Licia
It has been claimed recently that massive sterile neutrinos could bring about a new concordance between observations of the cosmic microwave background, the large-scale structure of the Universe, and local measurements of the Hubble constant, H0. We demonstrate that this apparent concordance results from combining data sets which are in…
Evidence for Bouncing Evolution Before Inflation After BICEP2
Zhang, Xinmin; Xia, Jun-Qing; Li, Hong +1 more
The BICEP2 Collaboration reports a detection of primordial cosmic microwave background (CMB) B mode with a tensor-to-scalar ratio r =0.20-0.05+0.07 (68% C.L.). However, this result disagrees with the recent Planck limit r<0.11 (95% C.L.) on constraining inflation models. In this Letter we consider an inflationary cosmology with a preceding nons…
Quantifying the BICEP2-Planck Tension over Gravitational Waves
Smith, Kendrick M.; Dvorkin, Cora; Boyle, Latham +4 more
The recent BICEP2 measurement of B-mode polarization in the cosmic microwave background (r =0.2-0.05+0.07), a possible indication of primordial gravity waves, appears to be in tension with the upper limit from WMAP (r<0.13 at 95% C.L.) and Planck (r <0.11 at 95% C.L.). We carefully quantify the level of tension and show that it is very signi…