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In this paper we study the inflation model driven by the phantom field. We propose a possible exit from phantom inflation to our observational cosmology by introducing an additional normal scalar field, similar to hybrid inflation model.…

Astrophysics · Physics 2016-08-30 Yun-Song Piao , Yuan-Zhong Zhang

We study how the initial inhomogeneities of the universe affect the onset of inflation in the closed universe. We consider the model of a chaotic inflation which is driven by a massive scalar field. In order to construct an inhomogeneous…

General Relativity and Quantum Cosmology · Physics 2009-10-28 Osamu Iguchi , Hideki Ishihara

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

Quantum diffusion describes the inflow of vacuum quantum fluctuations as they get amplified by gravitational instability, and stretched to large distances during inflation. In this picture, the dynamics of the universe's expansion becomes…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-12 Vincent Vennin , David Wands

One of the major pillars of modern cosmology theory is a period of accelerating expansion in the early universe. This accelerating expansion, or inflation, must be sustained for at least 30 e--foldings. One mechanism used to drive the…

High Energy Physics - Theory · Physics 2012-04-17 Damien A. Easson , Paul H. Frampton , George F. Smoot

We calculate power spectra of cosmological perturbations at high accuracy for two classes of inflation models. We classify the models according to the behaviour of the Hubble distance during inflation. Our approximation works if the Hubble…

Astrophysics · Physics 2009-11-06 Dominik J. Schwarz , Cesar A. Terrero-Escalante , Alberto A. Garcia

Inflation offers a simple model for very early evolution of our Universe and the origin of primordial perturbations on large scales. Over the last 25 years we have become familiar with the predictions of single-field models, but inflation…

Astrophysics · Physics 2008-11-26 David Wands

Cosmic inflation is the leading theory to explain early Universe history and structure formation. Non-oscillatory inflation is a class of models which can naturally introduce a post-inflationary stiff period of the Universe's evolution…

High Energy Physics - Phenomenology · Physics 2026-02-03 Lucy Brissenden , Konstantinos Dimopoulos , Eemeli Tomberg

We discuss the interaction between perturbations in the inflaton and the background during the preheating phase in simple inflationary models. By numerically solving the Einstein field equations we are able to assess the impact of…

High Energy Physics - Phenomenology · Physics 2009-10-31 Richard Easther , Matthew Parry

The next decade will feature an abundance of novel cosmological data, while many fundamental questions about inflation remain. Given this, there is ample need for maximally efficient calculations, especially in non-standard scenarios for…

General Relativity and Quantum Cosmology · Physics 2023-05-10 Panagiotis Christeas , Logan Thomas

This note makes a self-contained exposition of the basic facts of big bang cosmology as they relate to inflation. The fundamental problems with that model are then explored. A quartic scalar potential model of inflation is evaluated which…

General Physics · Physics 2014-12-09 Dan Green

Inflation models are compared with observation on the assumption that the curvature perturbation is generated from the vacuum fluctuation of the inflaton field. The focus is on single-field models with canonical kinetic terms, classified as…

High Energy Physics - Theory · Physics 2009-04-22 D H Lyth

We study the generation of the primordial curvature perturbation in multi-field inflation. Considering both the evolution of the perturbation during inflation and the effects generated at the end of inflation, we present a general formula…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Ki-Young Choi , Soo A Kim , Bumseok Kyae

We have studied modulated inflation that generates curvature perturbation from light-field fluctuation. As discussed in previous works, even if the fluctuation of the inflaton itself does not generate the curvature perturbation at the…

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

The accelerated expansion of the early universe is an integral part of modern cosmology and dynamically realized by the mechanism of inflation. The simplest theoretical description of the inflationary paradigm is based on the assumption of…

High Energy Physics - Phenomenology · Physics 2021-04-14 Christian F. Steinwachs

I review the current status of the theory of Cosmic Inflation. My discussion covers the motivation and implementation of the idea, as well as an analysis of recent successes and open questions. There is a special discussion of the physics…

Astrophysics · Physics 2007-05-23 Andreas Albrecht

In the standard cosmological picture the Universe underwent a brief period of near-exponential expansion, known as Inflation. This provides an explanation for structure formation through the amplification of perturbations by the rapid…

General Relativity and Quantum Cosmology · Physics 2019-04-03 Zack Fifer , Theo Torres , Sebastian Erne , Anastasios Avgoustidis , Richard J. A. Hill , Silke Weinfurtner

In a variety of inflation models the motion of the inflaton may trigger the production of some non-inflaton particles during inflation, for example via parametric resonance or a phase transition. Particle production during inflation leads…

Cosmology and Nongalactic Astrophysics · Physics 2010-01-07 Neil Barnaby , Zhiqi Huang

Inflation may have been driven by a component which violated the Null-Energy Condition, thereby leading to {\it super inflation}. We provide the formalism to study cosmological perturbations when such a component is described by a scalar…

Astrophysics · Physics 2010-09-21 Marco Baldi , Fabio Finelli , Sabino Matarrese

Most high-energy constructions that realise a phase of cosmic inflation contain many degrees of freedom. Yet, cosmological observations are all consistent with single-field embeddings. We show how volume selection effects explain this…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-24 Koki Tokeshi , Vincent Vennin