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Due to universality and attractor properties, $\alpha$-attractor quintessential inflation establishes direct relations between inflationary observables such as the scalar tilt $n_s$ and the tensor-to-scalar ratio $r$, and late-time dark…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-26 William Giarè , Eleonora Di Valentino , Eric V. Linder , Enrico Specogna

We report forecast constraints on warm inflation in the light of future cosmic microwave background (CMB) surveys, with data expected to be available in the coming decade. These observations could finally give us the missing information…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-04 F. B. M. dos Santos , G. Rodrigues , R. de Souza , J. S. Alcaniz

Single-field slow-roll inflation predicts a nearly scale-free power spectrum of perturbations, as observed at the scales accessible to current cosmological experiments. This spectrum is slightly red, showing a tilt $(1-n_s)\sim 0.04$. A…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-24 Julian B. Muñoz , Ely D. Kovetz , Alvise Raccanelli , Marc Kamionkowski , Joseph Silk

Inflation in a five-dimensional brane world model with two boundary branes is studied. We make use of the moduli space approximation whereby the low energy theory reduces to a four-dimensional biscalar-tensor gravity plus a minimally…

By incorporating both the tensor-to-scalar ratio and the measured value of the spectral index, we set a bound on solo small field inflation of $\Delta \phi / m_{Pl} \geq 1.00 \sqrt{r/0.1}$. Unlike previous bounds which require monotonic…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-30 Joseph Bramante , Sean Downes , Landon Lehman , Adam Martin

We present new constraints on spectator axion-${\rm U}(1)$ gauge field interactions during inflation using the latest $Planck$ (PR4) and BICEP/Keck 2018 data releases. This model can source tensor perturbations from amplified gauge field…

Cosmology and Nongalactic Astrophysics · Physics 2022-08-03 Paolo Campeti , Ogan Özsoy , Ippei Obata , Maresuke Shiraishi

We constrain models of single field inflation with the pre-\textit{Planck} CMB data. The data used here is the 9-year Wilkinson Microwave Anisotropy Probe (\textit{WMAP}) data, South Pole Telescope (SPT) data and Atacama Cosmology Telescope…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Cheng Cheng , Qing-Guo Huang , Yin-Zhe Ma

The $\alpha$-attractor inflationary models are nowadays favored by CMB Planck observations. Their similarity with canonical quintessence models motivates the exploration of a common framework that explains both inflation and dark energy. We…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-18 Carlos García-García , Pilar Ruíz-Lapuente , David Alonso , M. Zumalacárregui

We assay how inflationary models whose properties are dominated by the dynamics of a single scalar field are constrained by cosmic microwave background (CMB) data from the Wilkinson Microwave Anisotropy Probe (WMAP). We classify…

High Energy Physics - Phenomenology · Physics 2009-09-15 V. Barger , Hye-Sung Lee , Danny Marfatia

We investigate the observational signatures of three models of the early Universe in the $B$-mode polarization of the Cosmic Microwave Background (CMB) radiation. In addition to the standard single field inflationary model, we also consider…

Cosmology and Nongalactic Astrophysics · Physics 2011-01-27 Yin-Zhe Ma , Wen Zhao , Michael L. Brown

We provide the latest constraints on the power spectra of both scalar and tensor perturbations from the CMB data (including \textit{Planck}~2015, BICEP2 \& \textit{Keck Array} experiments) and the new BAO scales from SDSS-III BOSS…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-20 Qing-Guo Huang , Ke Wang , Sai Wang

We investigate the observational viability of a class of $\alpha$-attractors inflationary models in light of the most recent Cosmic Microwave Background (CMB) and Large-Scale Structure (LSS) data. By considering a double-well potential we…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-04 J. G. Rodrigues , S. Santos da Costa , J. S. Alcaniz

We revisit the constraints on inflation models by using the current cosmological observations involving the latest local measurement of the Hubble constant ($H_{0} = 73.00\pm 1.75$ km s $^{-1}$ Mpc$^{-1}$). We constrain the primordial power…

Cosmology and Nongalactic Astrophysics · Physics 2017-12-20 Rui-Yun Guo , Xin Zhang

We present a comprehensive study of warm hybrid inflation within the framework of $\alpha$-attractor models, where an axionic inflaton is coupled to a waterfall field in the presence of thermal dissipation. The model is analyzed for both…

High Energy Physics - Phenomenology · Physics 2026-01-16 Waqas Ahmed , Waqar Ahmad , Ahsan Illahi , M. Junaid

The increasingly stringent observational bounds on primordial gravitational waves strongly constrain inflationary model building, favoring scenarios that predict highly suppressed tensor perturbations. While many viable constructions rely…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-11 Panagiotis G. Stavros , Spyros Basilakos , Emmanuel N. Saridakis

In single-field, slow-roll inflationary models, scalar and tensorial (Gaussian) perturbations are both characterized by a zero mean and a non-zero variance. In position space, the corresponding variance of those fields diverges in the…

General Relativity and Quantum Cosmology · Physics 2014-11-20 I. Agullo , J. Navarro-Salas , Gonzalo J. Olmo , Leonard Parker

The recent observations from CMB have imposed a very stringent upper-limit on the tensor/scalar ratio $r$ of inflation models, $r < 0.064$, which indicates that the primordial gravitational waves (PGW), even though possible to be detected,…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-03 Taotao Qiu , Taishi Katsuragawa , Shulei Ni

We present observational constraints on a scalar-tensor gravity theory by $\chi^2$ test for CMB anisotropy spectrum. We compare the WMAP temperature power spectrum with the harmonic attractor model, in which the scalar field has its…

Astrophysics · Physics 2009-11-10 Ryo Nagata , Takeshi Chiba , Naoshi Sugiyama

This work investigates a single-field inflationary model, a specific class of the K-essence models where a coupling term exists between canonical Lagrangian and the potential. This coupling term has many effects on key inflationary…

General Relativity and Quantum Cosmology · Physics 2025-12-25 Fereshteh Felegary , Thammarong Eadkhong , Farruh Atamurotov , Phongpichit Channuie

We analyze the latest cosmic microwave background (CMB) constraints on the scalar spectral index $n_s$ and tensor-to-scalar ratio $r$ from Planck 2018, BICEP/Keck 2018, the Atacama Cosmology Telescope Data Release 6 (ACT DR6), and the South…

High Energy Physics - Phenomenology · Physics 2025-10-22 John Ellis , Marcos A. G. Garcia , Keith A. Olive , Sarunas Verner