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Due to intra-field gravitational interactions, field configurations have a strong negative component to their energy density at the planckian and transplanckian scales, conceivably resulting in a sequestration of the transplanckian field…

General Relativity and Quantum Cosmology · Physics 2010-03-30 Robert Brout

We present a new method to calculate the spectrum of (slow-roll) inflationary perturbations, inspired by the conjectured dS/CFT correspondence. We show how the standard result for the spectrum of inflationary perturbations can be obtained…

High Energy Physics - Theory · Physics 2014-11-18 Jan Pieter van der Schaar

It is argued that the order of the analytic expressions for the calculation of the primordial perturbations from inflation exerts a strong influence upon the results of the analysis of observables dynamics based on these expressions and,…

Astrophysics · Physics 2007-05-23 C. A. Terrero-Escalante

We develop a potential-independent cosmographic framework, in which cosmographic parameters are promoted to dynamical variables within a closed autonomous system. Although the cosmographic hierarchy is formally infinite, we achieve closure…

General Relativity and Quantum Cosmology · Physics 2026-05-13 Seturumane Tema , S. Shajidul Haque , Saurya Das , Peter Dunsby

Classic inflation, the theory described in textbooks, is based on the idea that, beginning from typical initial conditions and assuming a simple inflaton potential with a minimum of fine-tuning, inflation can create exponentially large…

Cosmology and Nongalactic Astrophysics · Physics 2014-08-18 Anna Ijjas , Paul J. Steinhardt , Abraham Loeb

We study the problem of initial conditions for slow-roll inflation along a plateau-like scalar potential within the framework of fluctuation-dissipation dynamics. We consider, in particular, that inflation was preceded by a…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-09 Mar Bastero-Gil , Arjun Berera , Robert Brandenberger , Ian G. Moss , Rudnei O. Ramos , Joao G. Rosa

We explore what can be said on the effective temperature and sound speed of a statistical ensemble of fluid phonons present at the onset of a conventional inflationary phase. The phonons are the actual normal modes of the gravitating and…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Massimo Giovannini

Improved general slow-roll formulae giving the primordial gravitational wave spectrum are derived in the present work. Also the first and second order general slow-roll inverse formulae giving the Hubble parameter $H$ in terms of the…

Astrophysics · Physics 2009-05-12 Minu Joy

For simple inflationary models, we provide a consistent and complete scheme by which the macro-physical details of early universe inflation may be determined explicitly from the underlying micro-physical theory. We examine inflationary…

High Energy Physics - Phenomenology · Physics 2007-05-23 D. Cormier

Inflation models based on scalar-tensor theories of gravity are formulated in the Jordan frame but most often analysed in the Einstein frame. The transformation between the frames is not always desirable. In this work we formulate slow-roll…

General Relativity and Quantum Cosmology · Physics 2022-10-28 Mindaugas Karčiauskas , José Jaime Terente Díaz

We propose a new class of inflationary solutions to the standard cosmological problems (horizon, flatness, monopole,...), based on a modification of old inflation. These models do not require a potential which satisfies the normal…

High Energy Physics - Theory · Physics 2007-05-23 Gia Dvali , Shamit Kachru

In this letter we study a model of inflation in which the inflationary regimen comes from a type of holographic energy density. In particular, we consider the Granda-Oliveros proposal for the holographic energy density, which contains two…

General Relativity and Quantum Cosmology · Physics 2023-02-15 A. Oliveros , Mario A. Acero

In this work, we study the $f(R)$ models of inflation in the context of gravity's rainbow theory. We choose three types of $f(R)$ models: $f(R)=R+\alpha (R/M)^{n},\,f(R)=R+\alpha R^{2}+\beta R^{2}\log(R/M^{2})$ and the Einstein-Hu-Sawicki…

General Relativity and Quantum Cosmology · Physics 2020-09-02 Areef Waeming , Phongpichit Channuie

We suggest a new type of hill-top inflation originating from the initial conditions in the form of the microcanonical density matrix for the cosmological model with a large number of quantum fields conformally coupled to gravity. Initial…

High Energy Physics - Theory · Physics 2016-01-27 A. O. Barvinsky , A. Yu. Kamenshchik , D. V. Nesterov

Inflation universally produces classical almost scale free Gaussian inhomogeneities of any light scalars. Assuming the coupling constants at the time of inflation depend on some light moduli fields, we encounter the generation of modulated…

Astrophysics · Physics 2009-11-10 Francis Bernardeau , Lev Kofman , Jean-Philippe Uzan

A new scenario of hybrid-like inflation is considered without using hybrid-type potential. Radiation raised continuously by a dissipating inflaton field keeps symmetry restoration in a remote sector, and the false-vacuum energy of the…

Cosmology and Nongalactic Astrophysics · Physics 2009-07-22 Tomohiro Matsuda

The slow rolling inflation is dual to the random walk of conformal zero-mode. The 2 dimensional Fokker-Planck theory predicts the slow roll parameters of 4d inflation theory. The O(N) enhancements of the two point functions, N is the…

High Energy Physics - Theory · Physics 2023-05-02 Yoshihisa Kitazawa

In non-canonical two-field inflation models, deviations from the canonical model can be captured by a parameter $\xi$. We show this parameter is usually one half of the slow-roll order and analytically calculate the primordial power spectra…

General Relativity and Quantum Cosmology · Physics 2017-12-06 Yun-Chao Wang , Towe Wang

We explore the inflationary phase of a scalar field with a kinetic term non-minimally coupled to gravity. We find that one of the slow-roll conditions is naturally consequence of the equation of motion of the scalar field. Thus, slow-roll…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-16 Amir Ghalee

The hallmark of the 4-parameter generalized entropy is that it can represent various known entropies proposed so far for suitable limits of the parameters, and thus the 4-parameter generalized entropy can be applied on additive as well as…

General Relativity and Quantum Cosmology · Physics 2024-07-12 Sergei D. Odintsov , Simone D'Onofrio , Tanmoy Paul