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We consider the prospects of probing features in the primordial power spectrum with future Cosmic Microwave Background (CMB) polarization measurements. In the scope of the inflationary scenario, such features in the spectrum can be produced…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-05 Dhiraj Kumar Hazra , Daniela Paoletti , Mario Ballardini , Fabio Finelli , Arman Shafieloo , George F. Smoot , Alexei A. Starobinsky

The recent BICEP2 B-mode polarization determination of an inflationary tensor-scalar ratio $r=0.2^{+0.07}_{-0.05}$ is in tension with simple scale-free models of inflation due to a lack of a corresponding low multipole excess in the…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-18 V Miranda , Wayne Hu , Peter Adshead

We consider the status of Higgs Inflation in light of the recently announced detection of B-modes in the polarization of the cosmic microwave background radiation by the BICEP2 collaboration. In order for the primordial B-mode signal to be…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-03 Jessica L. Cook , Lawrence M. Krauss , Andrew J. Long , Subir Sabharwal

We extend and improve the modeling and analysis of large-amplitude, sharp inflationary steps for second order corrections required by the precision of the Planck CMB power spectrum and for arbitrary Dirac-Born-Infeld sound speed. With two…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-18 V Miranda , Wayne Hu

Recent B-mode polarization observation seems to imply the tensor tilt $n_T\gtrsim 1$ at large angular scale, if the primordial signal is dominated. We show that for a primordial universe, which is in a slowly expanding genesis phase before…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 Zhi-Guo Liu , Hong Li , Yun-Song Piao

The recent detection by the BICEP2 collaboration of a high level of tensor modes has relevant implications which we briefly discuss in this short note. In particular, the large angle CMB B- mode polarisation seems to imply problematic…

Cosmology and Nongalactic Astrophysics · Physics 2014-05-28 Alex Kehagias , Antonio Riotto

We study the statistics of the primordial power spectrum in models where massless gauge vectors are coupled to the inflaton, paying special attention to observational implications of having fundamental or effective horizons embedded in a…

Cosmology and Nongalactic Astrophysics · Physics 2014-05-07 Mikjel Thorsrud , Federico R. Urban , David F. Mota

We investigate the ability of current CMB data to reliably constrain the form of the primordial power spectrum generated during inflation. We attempt to identify more exotic power spectra that yield equally good fits to the data as simple…

Astrophysics · Physics 2009-06-23 Brian A. Powell , William H. Kinney

In this work we explore the possibility of variations in the primordial scalar power spectrum around the power-law shape, as predicted by single-field slow-roll inflationary scenarios. We search for the trace of these fluctuations in a…

Cosmology and Nongalactic Astrophysics · Physics 2022-02-09 Marzieh Farhang , Muhammad Sadegh Esmaeilian

In view of the recent BICEP2 results [arXiv:1403.3985] which may be attributed to the observation of B-modes polarization of the CMB with tensor-to-scalar ratio $r=0.2_{-0.05}^{+0.07}$, we revisit M-flation model. Gauged M-flation is a…

High Energy Physics - Theory · Physics 2014-11-27 A. Ashoorioon , M. M. Sheikh-Jabbari

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…

General Relativity and Quantum Cosmology · Physics 2021-11-28 N. Malsawmtluangi , P. K. Suresh

We investigate to which extent and under which circumstances false vacuum energy ($V_0$) dominated slow-roll inflation is compatible with a large tensor-to-scalar ratio $r = O(0.1)$, as indicated by the recent BICEP2 measurement. With $V_0$…

High Energy Physics - Phenomenology · Physics 2014-10-23 Stefan Antusch , Francesco Cefala , David Nolde , Stefano Orani

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…

Cosmology and Nongalactic Astrophysics · Physics 2014-12-23 Cheng Cheng , Qing-Guo Huang , Sai Wang

The BICEP/$\textit{Keck}$ (BK) series of cosmic microwave background (CMB) polarization experiments has, over the past decade and a half, produced a series of field-leading constraints on cosmic inflation via measurements of the "B-mode"…

The measurement of a large tensor-to-scalar ratio by the BICEP2 experiment, r = 0.20 (-0.05)(+0.07), severely restricts the landscape of viable inflationary models and shifts attention once more towards models featuring large inflaton field…

High Energy Physics - Phenomenology · Physics 2015-06-19 Keisuke Harigaya , Masahiro Ibe , Kai Schmitz , Tsutomu T. Yanagida

The inflationary paradigm is extremely successful regarding predictions of temperature anisotropies in the CMB. However, inflation also makes predictions for a CMB B-mode polarization, which has not been detected. Moreover, the standard…

General Relativity and Quantum Cosmology · Physics 2018-07-24 Gabriel León , Abhishek Majhi , Elias Okon , Daniel Sudarsky

Observations of anisotropies in the cosmic microwave background by the Wilkinson Microwave Anisotropy Probe suggest the possibility of oscillations in the primordial density perturbation. Such deviations from the usually assumed scale-free…

Astrophysics · Physics 2011-02-16 Paul Hunt , Subir Sarkar

The combined Planck, BICEP/Keck Array and BAO measurements of the scalar spectral index and the tensor-to-scalar ratio from the cosmic microwave background observations severely constrain or completely rule out several models of…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-13 Diganta Das , Shreyas Revankar

The primordial spectrum of fluctuations may present a large peak as a result of enhancing features during inflation. This may include, but is not limited to, bumps in the inflaton's potential, phases of ultra-slow-roll or turns in…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-30 Shyam Balaji , Guillem Domenech , Joseph Silk

The effect of pre-inflation physics on the power spectrum of scalar perturbations is estimated and there is a possibility that the pre-inflation physics explains the Wilkinson Microwave Anisotropy Probe data if the length of inflation is…

Astrophysics · Physics 2007-05-23 Shiro Hirai
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