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A novel approach to quintessential inflation model building is studied, within the framework of $\alpha$-attractors, motivated by supergravity theories. Inflationary observables are in excellent agreement with the latest CMB observations,…

General Relativity and Quantum Cosmology · Physics 2017-06-23 Konstantinos Dimopoulos , Charlotte Owen

We emphasize that the estimation of cosmological parameters from cosmic microwave background (CMB) anisotropy data, such as the recent high resolution maps from BOOMERanG and MAXIMA-1, requires assumptions about the primordial spectra. The…

Astrophysics · Physics 2009-10-31 Jerome Martin , Alain Riazuelo , Dominik J. Schwarz

Inflation gives rise to a nearly scale-invariant spectrum of tensor perturbations (gravitational waves), their contribution to the Cosmic Background Radiation (CBR) anisotropy depends upon the present cosmological parameters as well as…

Astrophysics · Physics 2014-10-13 Michael S. Turner , Yun Wang

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 study quintessential inflation using a generalized exponential potential $V(\phi)\propto exp(-\lambda \phi^n/Mpl^n), n>1$, the model admits slow-roll inflation at early times and leads to close-to-scaling behaviour in the post…

General Relativity and Quantum Cosmology · Physics 2017-06-21 Chao-Qiang Geng , Chung-Chi Lee , M. Sami , Emmanuel N. Saridakis , Alexei A. Starobinsky

The inflationary cosmology paradigm is very successful in explaining the CMB anisotropy to the percent level. Besides the dependence on the inflationary model, the power spectra, spectral tilt and non-Gaussianity of the CMB temperature…

High Energy Physics - Theory · Physics 2014-02-18 Amjad Ashoorioon , Konstantinos Dimopoulos , M. M. Sheikh-Jabbari , Gary Shiu

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

We investigate how the constraint results of inflation models are affected by considering the latest local measurement of $H_0$ in the global fit. We use the observational data, including the Planck CMB full data, the BICEP2 and Keck Array…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-27 Xin Zhang

Upcoming measurements of the small-scale primary cosmic microwave background (CMB) temperature and polarization power spectra ($TT$/$TE$/$EE$) are anticipated to yield transformative constraints on new physics, including the effective…

Cosmology and Nongalactic Astrophysics · Physics 2022-01-26 Fiona McCarthy , J. Colin Hill , Mathew S. Madhavacheril

Recently observational lower bounds on the strength of cosmic magnetic fields were reported, based on gamma-ray flux from distant blazars. If inflation is responsible for the generation of such magnetic fields then the inflation energy…

Cosmology and Nongalactic Astrophysics · Physics 2012-10-23 Tomohiro Fujita , Shinji Mukohyama

Inflation scenarios kinetically coupled with the Einstein tensor have been widely studied. They can be consistent with current observational data. Future experiments on the measurement on CMB distortions will potentially extend information…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-20 Rui Dai , Yi Zhu

We constrain slow-roll inflationary models using the recent WMAP data combined with data from the VSA, CBI, ACBAR and 2dF experiments. We find the slow-roll parameters to be $0 < \epsilon_1 < 0.032$ and $\epsilon_2 + 5.0 \epsilon_1 = 0.036…

Astrophysics · Physics 2009-11-07 Samuel M Leach , Andrew R Liddle

We forecast the ability of cosmic microwave background (CMB) temperature and polarization datasets to constrain theories of eternal inflation using cosmic bubble collisions. Using the Fisher matrix formalism, we determine both the overall…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-21 Stephen M. Feeney , Franz Elsner , Matthew C. Johnson , Hiranya V. Peiris

In the measurements of cosmic microwave background polarizations, three frequency channels are necessary for discriminating the primordial B-modes from the polarized dust and the synchrotron emission. We carry out an optimistic estimate on…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-27 Qing-Guo Huang , Sai Wang

We update constraints on the Hubble function H(phi) during inflation, using the most recent cosmic microwave background (CMB) and large scale structure (LSS) data. Our main focus is on a comparison between various commonly used methods of…

Astrophysics · Physics 2009-06-23 Jan Hamann , Julien Lesgourgues , Wessel Valkenburg

The recent local measurement of the Hubble constant based on the distance-ladder method has reached a $1.91\%$ precision, but this result is in tension with the early-universe measurements at the more than 4$\sigma$ level, bringing a crisis…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-12 Rui-Yun Guo , Jing-Fei Zhang , Xin Zhang

Inflation models make specific predictions for a tensor-scalar-scalar three-point correlation, or bispectrum, between one gravitational-wave (tensor) mode and two density-perturbation (scalar) modes. This tensor-scalar-scalar correlation…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 Emanuela Dimastrogiovanni , Matteo Fasiello , Donghui Jeong , Marc Kamionkowski

We study the observational constraints of CMB temperature and polarization anisotropies on models of dark energy, with special focus on models with variation in properties of dark energy with time. We demonstrate that the key constraint…

Astrophysics · Physics 2014-10-13 H. K. Jassal , J. S. Bagla , T. Padmanabhan

We investigate the possibility of using future photometric and radio surveys to constrain the power spectrum of primordial fluctuations that is predicted by inflationary models with a violation of the slow-roll phase. We forecast…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-17 Mario Ballardini , Fabio Finelli , Roy Maartens , Lauro Moscardini

The precision reached by the recent CMB measurements gives new insights into the shape of the primordial power spectra of the cosmological perturbations. In the context of inflationary cosmology, this implies that the CMB data are now…

Astrophysics · Physics 2015-10-08 Christophe Ringeval