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Related papers: Starobinsky Inflation and the Latest CMB Data: A S…

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Starobinsky inflation and nonminimally coupled (NMC) Higgs inflation have been among the most favored models of the early Universe, as their predictions for the scalar spectral index $n_s$ and tensor-to-scalar ratio $r$ fall comfortably…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-26 Ioannis D. Gialamas , Alexandros Karam , Antonio Racioppi , Martti Raidal

Recent measurements from the Atacama Cosmology Telescope (ACT), particularly when combined with DESI baryon acoustic oscillation data, have reported a scalar spectral index $n_s$ slightly higher than that inferred by {\it Planck}~2018,…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-18 Jureeporn Yuennan , Farruh Atamurotov , Phongpichit Channuie

The $F(R)$ gravity models of inflation are revisited in light of the recent observations of cosmic microwave background radiation by Atacama Cosmology Telescope (ACT) and DESI Collaboration. A detailed study of the evolution equations in…

General Relativity and Quantum Cosmology · Physics 2025-12-18 Sergei V. Ketov , Ekaterina O. Pozdeeva , Sergey Yu. Vernov

This paper investigates Starobinsky's model of inflation driven by the trace anomaly of conformally coupled matter fields. This model does not suffer from the problem of contrived initial conditions that occurs in most models of inflation…

High Energy Physics - Theory · Physics 2009-10-31 S. W. Hawking , T. Hertog , H. S. Reall

We give a brief review of the basic principles of inflationary theory and discuss the present status of the simplest inflationary models that can describe Planck/BICEP/Keck observational data by choice of a single model parameter. In…

High Energy Physics - Theory · Physics 2025-10-28 Renata Kallosh , Andrei Linde

Potential slow-roll parameters are widely used in inflationary cosmology to estimate the scalar and tensor perturbation amplitudes and the scalar spectral index, although the inflationary observables are fundamentally expressed in terms of…

General Relativity and Quantum Cosmology · Physics 2026-05-19 Jose Mathew

We consider the Starobinsky inflation with a set of higher order corrections parametrised by two real coefficients $\lambda_1, \lambda_2$. In the Einstein frame we have found a potential with the Starobinsky plateau, steep slope and…

High Energy Physics - Theory · Physics 2015-02-06 Michal Artymowski , Zygmunt Lalak , Marek Lewicki

We consider an extension of the Starobinsky model, whose parameters are functions of an extra scalar field. Our motivation is to test the robustness (or sensitivity) of the Starobinsky inflation against mixing scalaron with another (matter)…

High Energy Physics - Theory · Physics 2016-02-17 Sho Kaneda , Sergei V. Ketov

In this work we study the scalar power spectrum and the spectral index for the Starobinsky inflationary model using the phase integral method up-to third-order of approximation. We show that the semiclassical methods reproduce the scalar…

General Relativity and Quantum Cosmology · Physics 2020-07-02 Truman Tapia , Muhammad Zahid Mughal , Clara Rojas

We investigate the pre-inflationary dynamics of inflation with the Starobinsky potential, favored by recent data from the Planck mission, using techniques developed to study cosmological perturbations on quantum spacetimes in the framework…

General Relativity and Quantum Cosmology · Physics 2016-03-23 Béatrice Bonga , Brajesh Gupt

Nonminimal coupling between the inflaton and the Ricci scalar plays a crucial role in shaping the predictions of single-field inflationary models. While a quartic potential with such coupling represents one of the simplest realizations…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-24 Waqas Ahmed , Mansoor Ur Rehman

The lack of correlations on the large scale cosmic microwave background (CMB) anisotropy provides a potential window to probe beyond the standard inflationary scenario. In this paper, we investigate the primordial power spectrum based on…

General Relativity and Quantum Cosmology · Physics 2019-03-29 Pisin Chen , Hsiao-Heng Yeh , Dong-han Yeom

We elaborate on the predictions of the imaginary Starobinsky model of inflation coupled to matter, where the inflaton is identified with the imaginary part of the inflaton multiplet suggested by the Supergravity embedding of a pure R + R^2…

High Energy Physics - Theory · Physics 2016-01-20 Sergio Ferrara , Alex Kehagias , Antonio Riotto

We discuss how Starobinsky-like inflation may emerge from dilaton dynamics in brane cosmology scenarios based on string theory, in which our universe is represented as a three-brane. The effective potential may acquire a constant term from…

High Energy Physics - Theory · Physics 2015-06-18 John Ellis , Nick E. Mavromatos , Dimitri V. Nanopoulos

We study inflationary dynamics within the framework of fractal cosmology, where space is characterized by an effective non-integer dimension $D$. In our work, fractal effects are sourced through thermodynamic modifications at the…

General Relativity and Quantum Cosmology · Physics 2026-03-31 Aarav Shah , Paulo Moniz , Maxim Khlopov , Oem Trivedi , Maxim Krasnov

We revisit higher order corrections to the Starobinsky inflationary model using the most recent P-ACT-LB-BK18 data, which exhibits a mild but definite tension with the predictions of the original model. Our results demonstrate how even…

High Energy Physics - Phenomenology · Physics 2026-02-23 Min Gi Park , Dhong Yeon Cheong , Seong Chan Park

We consider the ghost-free higher order corrections to the Starobinsky model in the old minimal supergravity. In general, higher order corrections cannot be forbidden by symmetries, which likely violate the flatness of the scalaron…

High Energy Physics - Theory · Physics 2015-01-26 Kohei Kamada , Jun'ichi Yokoyama

The magnitude of B-mode polarization in the cosmic microwave background as measured by BICEP2 favours models of chaotic inflation with a quadratic $m^2 \phi^2/2$ potential, whereas data from the Planck satellite favour a small value of the…

High Energy Physics - Phenomenology · Physics 2014-08-25 John Ellis , Marcos A. G. Garcia , Dimitri V. Nanopoulos , Keith A. Olive

The precision era of cosmology demands accurate theoretical predictions from inflationary models. In quantitative reheating analyses, inflationary observables depend sensitively on the number of e-folds between horizon exit and the end of…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-22 Debottam Nandi , Simran Yadav , Manjeet Kaur

We show that the universal $\alpha$-attractor models of inflation can be realized by including an auxiliary vector field $A_{\mu}$ for the Starobinsky model with the Lagrangian $f(R)=R+R^2/(6M^2)$. If the same procedure is applied to…

Cosmology and Nongalactic Astrophysics · Physics 2015-07-24 Mehmet Ozkan , Yi Pang , Shinji Tsujikawa