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The Starobinsky model is one of the inflation models consistent with the result of CMB observation by the Planck satellite. We consider the dynamics of the Starobinsky inflation in the presence of another scalar field with a large…

High Energy Physics - Phenomenology · Physics 2016-05-25 Shinta Kasuya , Kanto Moritake

We present the status of our study into the feasibility of estimating the parameters of inflation from planned satellite observations of the anisotropy of the cosmic microwave background (CMB).We describe a perturbative procedure for…

Detailed analyses of the WMAP data indicate possible oscillatory features in the primordial curvature perturbation, which moreover appears to be suppressed beyond the present Hubble radius. Such deviations from the usual inflationary…

Astrophysics · Physics 2014-11-18 Paul Hunt , Subir Sarkar

We show how estimates of parameters characterizing inflation-based theories of structure formation localized over the past year when large scale structure (LSS) information from galaxy and cluster surveys was combined with the rapidly…

We investigate the inflationary phenomenology of a marginally deformed Starobinsky model, motivated by quantum corrections to the $R^{2}$ term, in light of the latest cosmological observations. In this framework, the inflationary potential…

General Relativity and Quantum Cosmology · Physics 2025-09-30 Jureeporn Yuennan , Farruh Atamurotov , Phongpichit Channuie

We consider quantum corrections to a recently obtained perturbative form of Starobinsky model to extract information about the initial conditions of the universe leading to cosmological inflation. Integrating out graviton modes, we find…

General Relativity and Quantum Cosmology · Physics 2025-12-02 Abhijith Ajith , Hardik Jitendra Kuralkar , Sukanta Panda , Archit Vidyarthi

The first inflationary model conceived was the one proposed by Starobinsky which includes an additional term quadratic in the Ricci-scalar R in the Einstein-Hilbert action. The model is now considered a target for several future cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-27 S. Santos da Costa , M. Benetti , R. M. P. Neves , F. A. Brito , R. Silva , J. S. Alcaniz

Prior to recombination, Silk damping causes the dissipation of energy from acoustic waves into the monopole of the Cosmic Microwave Background (CMB), resulting in spectral distortions. These can be used to probe the primordial scalar power…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Sebastien Clesse , Björn Garbrecht , Yi Zhu

We analyze a class of generalized inflationary models proposed in Ref. [1], known as $\beta$-exponential inflation. We show that this kind of potential can arise in the context of brane cosmology, where the field describing the size of the…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-15 M. A. Santos , M. Benetti , J. S. Alcaniz , F. A. Brito , R. Silva

Non-commutative inflation is a modification of standard general relativity inflation which takes into account some effects of the space-time uncertainty principle motivated by ideas from string theory. The corrections to the primordial…

Astrophysics · Physics 2009-03-31 Shinji Tsujikawa , Roy Maartens , Robert Brandenberger

Cosmic microwave background (CMB) anisotropy may result from both scalar and tensor perturbations. For a sufficiently narrow range of angular scales, CMB perturbations can be characterized by four parameters. Results from the Cosmic…

Astrophysics · Physics 2009-10-22 Scott Dodelson , Lloyd Knox , Edward W. Kolb

Testing the so-called consistency relations plays an important role for distinguishing the different classes of inflation models. In this paper, we investigate the possible testing based on the potential observations of the cosmic microwave…

Cosmology and Nongalactic Astrophysics · Physics 2011-11-09 W. Zhao , Q. -G. Huang

In forthcoming years, connections between cosmology and particle physics will be made increasingly important with the advent of a new generation of cosmic microwave background (CMB) experiments. Here, we review a number of these links. Our…

Astrophysics · Physics 2008-11-26 Marc Kamionkowski , Arthur Kosowsky

We point out that the inclusion of a string component contributing around 5% to the CMB power spectrum amplitude on large scales can increase the preferred value of the spectral index n_s of density fluctuations measured by CMB experiments.…

Astrophysics · Physics 2009-11-11 Richard A. Battye , Bjorn Garbrecht , Adam Moss

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

The original Starobinsky $R + R^2$ model of inflation is consistent with Planck and other measurements of the CMB, but recent results from the ACT and SPT Collaborations hint that the tilt of scalar perturbations may be in tension with the…

High Energy Physics - Phenomenology · Physics 2025-08-20 John Ellis , Marcos A. G. Garcia , Natsumi Nagata , Dimitri V. Nanopoulos , Keith A. Olive

Measurements of the cosmic microwave background (CMB) favour models of inflation with a small tensor-to-scalar ratio r, as predicted by the Starobinsky R + R^2 model. It has been shown previously that various models based on no-scale…

High Energy Physics - Theory · Physics 2019-08-07 John Ellis , Dimitri V. Nanopoulos , Keith A. Olive , Sarunas Verner

The recent measurements of cosmological parameters by the Planck collaboration favors inflationary models with a redshifted spectrum and a very low tensor-to-scalar ratio. Two well-studied scenarios in the particle physics/string theory…

High Energy Physics - Phenomenology · Physics 2014-01-31 Sean Downes

We investigate the degree to which the Cosmic Microwave Background (CMB) can be used to constrain primordial non-Gaussianity coming from the presence of spinning particles coupled to the inflaton. We compute the $\langle TTT \rangle$ and…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-09 Lorenzo Bordin , Giovanni Cabass

An important unsolved problem that affects practically all attempts to connect string theory to cosmology and phenomenology is how to distinguish effective field theories belonging to the string landscape from those that are not consistent…

High Energy Physics - Theory · Physics 2019-02-20 Ana Achúcarro , Gonzalo A. Palma