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We present a technique, {\em the uniform asymptotic approximation}, to construct accurate analytical solutions of the linear perturbations of inflation after quantum effects of the early universe are taken into account, for which the…

Cosmology and Nongalactic Astrophysics · Physics 2014-02-19 Tao Zhu , Anzhong Wang , Gerald Cleaver , Klaus Kirsten , Qin Sheng

In this work, we develop and apply the WKB approximation to several examples of noncommutative quantum cosmology, obtaining the time evolution of the noncommutative universe, this is done starting from a noncommutative quantum formulation…

General Relativity and Quantum Cosmology · Physics 2009-03-24 E. Mena , O. Obregon , M. Sabido

This paper introduces a novel deep learning method, called DeepWKB, for estimating the invariant distribution of randomly perturbed systems via its Wentzel-Kramers-Brillouin (WKB) approximation $u_\epsilon(x) = Q(\epsilon)^{-1}…

Dynamical Systems · Mathematics 2025-08-14 Yao Li , Yicheng Liu , Shirou Wang

This article provides an introductory review of inflation and cosmological perturbation theory. I begin by motivating the need for an epoch of inflation during the early stages of the radiation dominated era, and describe how inflation is…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-08 L. Sriramkumar

The ultra-slow-roll (USR) inflationary models predict large-amplitude scalar perturbations at small scales which can lead to the primordial black hole production and scalar-induced gravitational waves. In general scalar perturbations in the…

Cosmology and Nongalactic Astrophysics · Physics 2020-04-29 Jing Liu , Zong-Kuan Guo , Rong-Gen Cai

Exploring gravitational theories beyond general relativity (GR) with black hole (BH) spectroscopy requires accurate and flexible methods for computing their quasinormal mode (QNM) spectrum. A popular method of choice is the higher-order…

General Relativity and Quantum Cosmology · Physics 2026-05-05 Ruijing Tang , Nicola Franchini , Sebastian H. Völkel , Emanuele Berti

We compute the rate with which super-Hubble cosmological fluctuations are decohered during inflation, by their gravitational interactions with unobserved shorter-wavelength scalar and tensor modes. We do so using Open Effective Field Theory…

High Energy Physics - Theory · Physics 2023-07-12 C. P. Burgess , R. Holman , Greg Kaplanek , Jerome Martin , Vincent Vennin

A thorough MCMC analysis of any inflationary model against the current cosmological data is essential for assessing the validity of such a model as a viable inflationary model. Warm Inflation, producing both thermal and quantum…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-29 Umang Kumar , Suratna Das

We propose an extension of Wenzel-Kramers-Brillouin (WKB) approximation for solving the Schr\"odinger equation. A set of coupled differential equations is obtained by considering an ansatz of the wave function with an auxiliary condition on…

Quantum Physics · Physics 2025-04-01 Yu-An Tsai , Sheng D. Chao

A brief review of inflation is presented. After having demonstrated the generality of the inflationary mechanism, the emphasize is put on its simplest realization, namely the single field slow-roll inflationary scenario. Then, it is shown…

Astrophysics · Physics 2007-05-23 Jerome Martin

We formalize the Hubble slow-roll formalism for inflationary dynamics in Randall-Sundrum Type II braneworld cosmologies, defining Hubble slow-roll parameters which can be used along with the Hamilton-Jacobi formalism. Focussing on the…

Astrophysics · Physics 2009-11-10 Erandy Ramirez , Andrew R. Liddle

Cosmic inflation, which describes an accelerated expansion of the early Universe, yields the most successful predictions regarding temperature anisotropies in the cosmic microwave background (CMB). Nevertheless, the precise origin of the…

General Relativity and Quantum Cosmology · Physics 2020-08-14 Gabriel Leon , Maria Pia Piccirilli

Quantum fields exhibit non-trivial behaviours in curved space-times, especially around black holes or when a cosmological constant is added to the field equations. A new scheme, based on the Wentzel-Kramers-Brillouin (WKB) approximation is…

High Energy Physics - Theory · Physics 2008-11-26 J. Grain , A. Barrau

We develop a frame-covariant formulation of inflation in the slow-roll approximation by generalizing the inflationary attractor solution for scalar-curvature theories. Our formulation gives rise to new generalized forms for the potential…

High Energy Physics - Phenomenology · Physics 2016-06-22 Daniel Burns , Sotirios Karamitsos , Apostolos Pilaftsis

We propose new slow-roll approximations for inflationary models with the Gauss-Bonnet term. We find more accurate expressions of the standard slow-roll parameters as functions of the scalar field. To check the accuracy of approximations…

General Relativity and Quantum Cosmology · Physics 2024-09-24 Ekaterina O. Pozdeeva , Maria A. Skugoreva , Alexey V. Toporensky , Sergey Yu. Vernov

We investigate the accuracy of the slow-roll approximation for calculating perturbation spectra generated during inflation. The Hamilton-Jacobi formalism is used to evolve inflationary models with different histories. Models are identified…

Astrophysics · Physics 2010-10-27 Sirichai Chongchitnan , George Efstathiou

The inflationary and pre-inflationary evolution of scalar modes of cosmological perturbations in a closed universe is analyzed for a loop quantum cosmology model with an inflationary regime consistent with the constraints on inflation…

General Relativity and Quantum Cosmology · Physics 2024-11-26 Lucas M. V. Montese , Nelson Yokomizo

A self-consistent pre-inflationary extension of the inflationary scenario with the Starobinsky potential, favored by Planck data, is studied using techniques from loop quantum cosmology (LQC). The results are compared with the quadratic…

General Relativity and Quantum Cosmology · Physics 2016-05-25 Béatrice Bonga , Brajesh Gupt

The implications of the WMAP (Wilkinson Microwave Anisotropy Probe) third year data for inflation are investigated using both the slow-roll approximation and an exact numerical integration of the inflationary power spectra including a…

Astrophysics · Physics 2009-11-11 Jerome Martin , Christophe Ringeval

I discuss the current status of inflationary cosmology in light of the recent WMAP 3-year data release. The basic predictions of inflation are all supported by the data. Inflation also makes predictions which have not been well tested by…

Astrophysics · Physics 2009-06-23 William H. Kinney