Related papers: On quantifying and resolving the BICEP2/Planck ten…
We present results from an analysis of all data taken by the BICEP2/Keck CMB polarization experiments up to and including the 2015 observing season. This includes the first Keck Array observations at 220 GHz and additional observations at…
We investigate the degeneracy of the isocurvature perturbations and the primordial gravitational waves, by using recent observations of the cosmic microwave background (CMB) reported by Planck and BICEP2 collaborations. We show that the…
The recent background imaging of cosmic extragalactic polarization (BICEP2) observations are believed as an evidence for the cosmic inflation. BICEP2 provided a first direct evidence for the inflation, determined its energy scale and…
In this paper we constrain the tilt of the spectra of primordial gravitational waves from Background Imaging of Cosmic Extragalactic Polarization (BICEP2) data only. We find $r=0.21_{-0.10}^{+0.04}$ and $n_t=-0.06_{-0.23}^{+0.25}$ (at…
Inspired by quantum gravitational physics, the approach of non-commutative (NC) phase space leads to a modified dispersion relation of gravitational waves. This feature, if applied to the very early universe, gives rise to a modified power…
Non-inflationary sources of gravitational waves in the early Universe generically predict causality-limited tensor power spectra at low frequencies. We report the first-ever constraints on such sources based on cosmic microwave background…
We present results from an analysis of all data taken by the BICEP2, Keck Array and BICEP3 CMB polarization experiments up to and including the 2018 observing season. We add additional Keck Array observations at 220 GHz and BICEP3…
If the B-mode signal in the CMB polarization seen by the BICEP2 experiment is confirmed, it has dramatic implications for models of inflation. The result is also in tension with Planck limits on standard inflationary models. It is therefore…
The Hubble tension that the standard $\Lambda$CDM model is suffering from can be resolved with pre-recombination early dark energy. We present the first constraint on the tensor-to-scalar ratio $r$ in corresponding Hubble-tension-free…
The BICEP2 experiment has announced a signal for primordial gravity waves with tensor-to-scalar ratio $r=0.2^{+0.07}_{-0.05}$ [arXiv:1403.3985]. There are two ways to reconcile this result with the latest Planck experiment…
We present new, tight, constraints on the cosmological background of gravitational waves (GWs) using the latest measurements of CMB temperature and polarization anisotropies provided by the Planck, BICEP2 and Keck Array experiments. These…
A joint analysis of data collected by the Planck and BICEP2+Keck teams has previously given $r = 0.09^{+0.06}_{-0.04}$ for BICEP2 and $r = 0.02^{+0.04}_{-0.02}$ for Keck. Analyzing BICEP2 using its published noise estimate, we had earlier…
We show the possibility that the observational results of the primordial gravitational waves from Planck and BICEP2 for the tensor-to-scalar ratio $r$ can be reconciled when an early dark energy was included. This early dark energy behaves…
We make a joint analysis of BICEP2 and recently released Planck HFI 353 GHz dust polarization data, and find that there is no evidence for the primordial gravitational waves and the bound on the tensor-to-scalar ratio becomes $r<0.083$ at…
We show that the tension introduced by the detection of large amplitude gravitational wave power by the BICEP2 experiment with temperature anisotropy measurements by the Planck mission is alleviated in models where extra light species…
For the simplest inflation models, the recent detection of a large primordial B-mode polarization signal by the BICEP2 experiment indicates a slight tension with the upper limit on the tensor-to-scalar ratio, $r$, from the Planck satellite.…
The detection of primordial gravitational waves is one of the biggest challenges of the present time. The existing (Wilkinson Microwave Anisotropy Probe) observations are helpful on the road to this goal, and the forthcoming experiments…
The recent detection of the primordial gravitational waves from the BICEP2 observation seems to be in tension with the upper bound on the amplitude of tensor perturbations from the PLANCK data. We consider a phenomenological model of…
The effect of primordial massive gravitational waves on the BB-mode correlation angular power spectrum of CMB is studied for several inflation models. The angular power spectrum with the BICEP2/Keck Array and Planck joint data suggests…
We show that the recently released B-mode polarisation data from the South Pole Telescope (SPT) favour a non-vanishing contribution of primordial gravitational waves of inflationary origin which is in tension with the previous BICEP-Keck…