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We have re-examined Mukhanov parametrization for inflationary equation of state, $1+\omega=\frac{\beta}{({N}+1)^\alpha}$, in the light of Planck 2018 results and latest bound of tensor-to-scalar ratio employing Hamilton-Jacobi formalism. We…

General Relativity and Quantum Cosmology · Physics 2025-06-27 Barun Kumar Pal

We present a novel approach for setting initial conditions on the mode functions of the Mukhanov Sazaki equation. These conditions are motivated by minimisation of the renormalised stress-energy tensor, and are valid for setting a vacuum…

General Relativity and Quantum Cosmology · Physics 2016-08-24 W. J. Handley , A. N. Lasenby , M. P. Hobson

In this paper we construct a bounce model that mimics the Starobinsky inflationary model. Our construction relies on Wands' duality, which shows that the Mukhanov-Sasaki equation has a symmetry transformation by changing appropriately its…

General Relativity and Quantum Cosmology · Physics 2019-05-22 L. F. Guimarães , F. T. Falciano , G. Brando

We study modulated inflation from kinetic term. Using the Mukhanov-Sasaki variable, it is possible to determine how mixing induced by the kinetic term feeds the curvature perturbation with the isocurvature perturbation. We show explicitly…

High Energy Physics - Theory · Physics 2008-11-26 Tomohiro Matsuda

In this work, we solved the scalar and tensor perturbation equations numerically and using the improved uniform approximation method together with the third-order phase-integral method, for the $\alpha$-attractor inflationary model. This…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-13 Jordan Zambrano , Miguel Agama , Marcos Garzón , Werner Bramer-Escamilla , Clara Rojas , Teófilo Vargas

We derive a general expression for the power spectra of scalar and tensor fluctuations generated during inflation given an arbitrary choice of boundary condition for the mode function at a short distance. We assume that the boundary…

High Energy Physics - Theory · Physics 2008-11-26 Richard Easther , Brian R. Greene , William H. Kinney , Gary Shiu

In this Thesis by publication, we cover both phenomenological and theoretical approaches to the study of inflation: from model-independent parametrizations to modifications of gravity. In a review style, we provide a short introduction to…

General Relativity and Quantum Cosmology · Physics 2019-06-25 Héctor Ramírez

We investigate the cosmic inflation within a class of the scalar-tensor model with the scalar-dependent non-minimal kinetic couplings. The inflationary dynamical potential will be applied. Using the slow-roll approximation, we compute…

General Relativity and Quantum Cosmology · Physics 2025-12-01 Feyzollah Younesizadeh , Davoud Kamani

It has been argued that the standard inflationary scenario suffers from a serious deficiency as a model for the origin of the seeds of cosmic structure: it can not truly account for the transition from an early homogeneous and isotropic…

General Relativity and Quantum Cosmology · Physics 2013-03-25 Alberto Diez-Tejedor , Gabriel León , Daniel Sudarsky

An alternative inflationary model is proposed predicated upon a consideration of the form of the uncertainty principle in a curved background spacetime. An argument is presented suggesting a possible curvature dependence in the correct…

General Relativity and Quantum Cosmology · Physics 2014-05-12 Paul J. Camp , John L. Safko

This paper revisits the Inflationary scenario within the framework of scalar field models possessing a non-canonical kinetic term. We obtain closed form solutions for all essential quantities associated with chaotic inflation including slow…

Cosmology and Nongalactic Astrophysics · Physics 2012-10-03 Sanil Unnikrishnan , Varun Sahni , Aleksey Toporensky

The full set of cosmological observables coming from linear scalar and tensor perturbations of loop quantum cosmology is computed in the presence of inverse-volume corrections. Background inflationary solutions are found at linear order in…

General Relativity and Quantum Cosmology · Physics 2011-03-28 Martin Bojowald , Gianluca Calcagni

We have studied inflationary paradigm through an inflationary equation of state. With a single parameter equation of state as a function of the scalar field responsible for accelerated expansion, we find an observationally viable model…

General Relativity and Quantum Cosmology · Physics 2023-05-10 Barun Kumar Pal

We present a new approach to constructing inflationary models in closed universes. Conformal embedding of closed-universe models in a de Sitter background suggests a quantisation condition on the available conformal time. This condition…

Astrophysics · Physics 2009-11-10 Anthony Lasenby , Chris Doran

We present a rigorous and comprehensive investigation of a generalized inflationary perturbation theory designed to address persistent large-scale anomalies in the Cosmic Microwave Background (CMB). Motivated by the Trans-Planckian problem…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-09 Mahdieh Eskandari Merajin

This article reviews the properties of the quantum state of inflationary perturbations. After a brief description of the inflationary background, the wavefunction of the Mukhanov-Sasaki variable is calculated and shown to be that of a…

High Energy Physics - Theory · Physics 2015-06-11 Jerome Martin

If a coupling between the inflaton and the Gauss-Bonnet term is introduced, many models of inflation that were ruled out by the most recent Planck data can be made viable again. The predictions for the scalar spectral index and…

General Relativity and Quantum Cosmology · Physics 2025-04-22 Kamil Mudrunka , Kazunori Nakayama

In this short note we clarify the role of the boundary terms in the calculation of the leading order tree-level bispectrum in a fairly general minimally coupled single field inflationary model, where the inflaton's Lagrangian is a general…

Cosmology and Nongalactic Astrophysics · Physics 2011-06-30 Frederico Arroja , Takahiro Tanaka

We investigate the quantum dynamics of the quasi-isotropic inflationary solution. This is achieved by deriving the Lagrangian and Hamiltonian for both the FLRW background and the inhomogeneous correction, via an expansion of the…

General Relativity and Quantum Cosmology · Physics 2022-12-19 Nicola Bortolotti , Giovanni Montani

In this paper, we investigate various inflation models in the context of the no-boundary proposal. We propose that a good inflation model should satisfy three conditions: observational constraints, plausible initial conditions, and…

General Relativity and Quantum Cosmology · Physics 2014-06-09 Dong-il Hwang , Dong-han Yeom
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