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Recently, it has been found that complete resolution of the Hubble tension might point to a scale-invariant Harrison-Zeldovich spectrum of primordial scalar perturbation, i.e. $n_s=1$ for $H_0\sim 73$km/s/Mpc. We show that for well-known…

Cosmology and Nongalactic Astrophysics · Physics 2022-12-14 Gen Ye , Jun-Qian Jiang , Yun-Song Piao

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

In a recent paper, we suggested that the density fluctuation spectra arising from power-law (or extended) inflation, which are tilted with respect to the Harrison--Zel'dovich spectrum, may provide an explanation for the excess large scale…

Astrophysics · Physics 2007-05-23 David H Lyth , Andrew A Liddle

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 revisit the Cosmic Microwave Background (CMB) constraints on the spatial curvature of the Universe, assessing how they change when the curvature parameter and the primordial inflationary scalar spectrum are treated consistently within…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-01 Enrico Specogna , Tatevik Vardanyan , William Giarè , Eleonora Di Valentino

The recent results on the baryon acoustic oscillations measurements from the DESI collaboration have shown tantalizing hints for a time-evolving dark energy equation of state parameter $w(z)$, with a statistically significant deviation from…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-14 George Alestas , Marienza Caldarola , Sachiko Kuroyanagi , Savvas Nesseris

A self-consistent model which can unify Starobinsky inflation and the $\Lambda$CDM model in the framework of Poincar\'e gauge cosmology (PGC) is studied in this work, without extra inflaton and ``dark energy''. We start from the general…

General Relativity and Quantum Cosmology · Physics 2019-10-07 Hongchao Zhang , Lixin Xu

In this work, we study early-time inflation within a class of $f(R, \phi, X)$ gravity models under a constant-roll condition. Employing a generalized potential of the form $V(\phi)^\sigma$, we derive expressions for the spectral index $n_s$…

General Relativity and Quantum Cosmology · Physics 2025-10-15 Ali I. Keskin , Mehmet Yaşar , K. Kurt

String Theory and Supergravity allow, in principle, to follow the transition of the inflaton from pre-inflationary fast roll to slow roll. This introduces an infrared depression in the primordial power spectrum that might have left an…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-14 A. Gruppuso , N. Kitazawa , N. Mandolesi , P. Natoli , A. Sagnotti

In this paper we develop the formalism for the stochastic approach to inflation at all order in slow-roll parameters. This is done by including the momentum and Hamiltonian constraints into the stochastic equations. We then specialise to…

General Relativity and Quantum Cosmology · Physics 2022-02-09 Diego Cruces , Cristiano Germani

Inflation is a necessary cosmic mechanism to cure basic inconsistencies of the standard model of cosmology. These problems are usually `fixed' by postulating the existence of a scalar field (called the ``inflaton''). However, other less ad…

General Relativity and Quantum Cosmology · Physics 2026-01-16 Joan Solà Peracaula , Àlex González-Fuentes , Cristian Moreno-Pulido

We show that a supersymmetric renormalizable theory based on gauge group SO(10) and Higgs system {\bf {10 $\oplus$ 210 $\oplus$ 126 $\oplus$ $\overline{\bf 126}$}} with no scale supergravity can lead to a Starobinsky kind of potential for…

High Energy Physics - Phenomenology · Physics 2015-10-28 Ila Garg , Subhendra Mohanty

This paper presents the CMB angular power spectrum obtained using the \texttt{CAMB} code for three different models of inflation: the Starobinsky inflationary model, the generalized Starobinsky inflationary model, and the chaotic…

General Relativity and Quantum Cosmology · Physics 2024-10-23 Daniel Pozo , Lenin Calvache , Esteban Orozco , Vicente A. Arévalo , Clara Rojas

The present study connects inflation and freeze-in type dark matter (DM) within the same setup. Although the observables in these two phenomena lie at vastly different energy scales, they have been properly handled using the RG running of…

High Energy Physics - Phenomenology · Physics 2025-07-01 Sarif Khan , Sourov Roy , Ananya Tapadar

Space-based missions studying the cosmic microwave background (CMB) have progressively refined the parameter space in conventional models of inflation shortly ($\sim 10^{-37}$ seconds) after the big bang. While most inflationary scenarios…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-18 Jingwei Liu , Fulvio Melia

In this work we construct a formalism that can reveal the general characteristics of classes of viable $F(R)$ inflationary theories. The assumptions we make is that the slow-roll era occurs, and that the de Sitter scalaron mass $m^2(R)$ of…

General Relativity and Quantum Cosmology · Physics 2025-09-30 V. K. Oikonomou

In the recent time, inflationary cosmology is facing an existential crisis due to the proposed Swampland criterion which aims to evade any (meta-)stable de Sitter construction within the String landscape. It is been realised that a single…

Cosmology and Nongalactic Astrophysics · Physics 2020-11-02 Rathin Adhikari , Mayukh Raj Gangopadhyay , Yogesh

Motivated by Planck confirmation of an anomalously low value of the CMB temperature fluctuations up to multipole $\ell<40$, we in this paper try to explain such feature by investigating case of punctuated inflation scenario. This form of…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-11 Mussadiq H. Qureshi , Asif Iqbal , Manzoor A. Malik , Tarun Souradeep

Precise cosmological data from WMAP and forthcoming CMB experiments motivate the study of the quantum corrections to the slowroll inflationary parameters.We find the quantum (loop) corrections to the equations of motion of the classical…

Astrophysics · Physics 2009-11-10 D. Boyanovsky , H. J. de Vega , N. G. Sanchez

Short baseline neutrino experiments, like LSND and MiniBooNE experiments, pointed towards the existence of eV mass scale sterile neutrinos. To reconcile sterile neutrinos with cosmology self interaction between sterile neutrinos has been…

Cosmology and Nongalactic Astrophysics · Physics 2020-04-22 Arindam Mazumdar , Subhendra Mohanty , Priyank Parashari