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This paper investigates a scale-invariant inflationary model characterized by a scalar field non-minimally coupled to gravity and a curvature term quadratic in the Ricci scalar. The model's dynamic is analyzed using a full numerical…

高能物理 - 理论 · 物理学 2024-10-10 Mariaveronica De Angelis , Chiara Cecchini , Massimiliano Rinaldi

The regularization of the CMB power spectrum is an important issue of cosmology. Most approaches assume that there is no need to regularize the power spectrum, while Parker advocated the new regularization approach for the power spectrum in…

广义相对论与量子宇宙学 · 物理学 2015-06-15 Yukari Nakanishi

Following an elegant approach that merge the effects of the stringy spacetime uncertainty relation into primordial perturbations suggested by Brandenberger and Ho, we show the mode equation up to the first order of non-commutative…

高能物理 - 理论 · 物理学 2009-11-10 Dao-jun Liu , Xin-zhou Li

We update the constraints on the power spectra of primordial curvature perturbation and tensor perturbation including Planck data 2015 (P15) and recently released BICEP2/Keck data (BK15), Baryon Acoustic Oscillation data and the Type Ia…

宇宙学与河外天体物理 · 物理学 2023-02-15 Jun Li , Qing-Guo Huang

We derive analytic bounds on the shape of the primordial power spectrum in the context of single-field inflation. In particular, the steepest possible growth has a spectral index of $n_s - 1 = 4$ once transients have died down. Its primary…

宇宙学与河外天体物理 · 物理学 2019-06-24 Christian T. Byrnes , Philippa S. Cole , Subodh P. Patil

Nongaussian statistics are a powerful discriminant between inflationary models, particularly those with noncanonical kinetic terms. Focusing on theories where the Lagrangian is an arbitrary Lorentz-invariant function of a scalar field and…

宇宙学与河外天体物理 · 物理学 2015-03-19 Clare Burrage , Raquel H. Ribeiro , David Seery

Formulae are derived for the spectra of scalar curvature perturbations and gravitational waves produced during inflation, special cases of which include power law inflation, natural inflation in the small angle approximation and inflation…

广义相对论与量子宇宙学 · 物理学 2008-11-26 E. D. Stewart , D. H. Lyth

Recently in hep-ph/0605035 and hep-ph/0608138, we have shown that primordial inflation can be embedded within the Minimal Supersymmetric Standard Model, while providing the right amplitude for the density perturbations and a tilted spectrum…

高能物理 - 唯象学 · 物理学 2007-05-23 Rouzbeh Allahverdi , Anupam Mazumdar

During inflation, there is a preferred reference frame in which the expansion of the background spacetime is spatially isotropic. In contrast to Minkowski spacetime, observables can depend on the velocity of the system with respect to this…

广义相对论与量子宇宙学 · 物理学 2021-02-16 Tanguy Grall , Scott Melville

The statistical properties of the primordial density perturbations has been considered in the past decade as a powerful probe of the physical processes taking place in the early universe. Within the inflationary paradigm, the properties of…

广义相对论与量子宇宙学 · 物理学 2015-06-15 Gabriel Leon , Daniel Sudarsky

In this letter, we propose a model of inflationary cosmology with a bounce preceded and study its primordial curvature perturbations. Our model gives rise to a primordial power spectrum with a feature of oscillation on large scales compared…

天体物理学 · 物理学 2009-02-02 Yi-Fu Cai , Tao-tao Qiu , Jun-Qing Xia , Xinmin Zhang

Effects of heavy fields on primordial spectra of curvature perturbations are discussed in inflationary models with a sudden turning trajectory. When heavy fields are excited after the sudden turn and oscillate around the bottom of the…

高能物理 - 理论 · 物理学 2014-03-26 Toshifumi Noumi , Masahide Yamaguchi

Different inflationary models predict oscillatory features in the primordial power spectrum. These can leave an imprint on both the cosmic microwave background (CMB) and the large-scale structure (LSS) of our Universe, that can be searched…

宇宙学与河外天体物理 · 物理学 2019-02-15 Chenxiao Zeng , Ely D. Kovetz , Xuelei Chen , Yan Gong , Julian B. Muñoz , Marc Kamionkowski

In this paper we use two methods to constrain the the canonical single-field slow-roll inflation model. The first method exploits the analytic slow-roll-parameter dependence of primordial perturbations, and the second consists of a…

宇宙学与河外天体物理 · 物理学 2025-11-17 Jun Li , Guang-Hai Guo

We propose a novel mechanism for realizing slow-roll inflation that is fully consistent with observational data, based on conformal transformations acting exclusively on a complex scalar field -- without coupling to the gravitational…

高能物理 - 理论 · 物理学 2026-05-12 Kenji Ebata , So Katagiri , Yoshiki Matsuoka , Takaaki Sehara , Akio Sugamoto

We present a consistent \delta N formalism for curvature perturbations in anisotropic cosmological backgrounds. We employ our \delta N formalism to calculate the power spectrum, the bispectrum and the trispectrum in models of anisotropic…

宇宙学与河外天体物理 · 物理学 2015-06-15 Ali Akbar Abolhasani , Razieh Emami , Javad T. Firouzjaee , Hassan Firouzjahi

The inflationary cosmology is analyzed from the point of view of squeezed quantum states. As noted by Grishchuk and Sidorov, the amplification of quantum fluctuations into macroscopic perturbations which occurs during cosmic inflation is a…

天体物理学 · 物理学 2010-04-08 Andreas Albrecht , Pedro Ferreira , Michael Joyce , Tomislav Prokopec

Inflation predicts the generation of cosmological perturbations. Usually, the power spectra for the scalar and tensor modes are calculated with help of the slow roll approximation. In the case of power law inflation an exact result is…

天体物理学 · 物理学 2007-05-23 Dominik J. Schwarz , Jerome Martin

We investigate the effects of non-zero spatial curvature on cosmic inflation in the light of cosmic microwave background (CMB) anisotropy measurements from the Planck 2018 legacy release and from the 2015 observing season of BICEP2 and the…

宇宙学与河外天体物理 · 物理学 2022-10-12 Lukas T. Hergt , Fruzsina J. Agocs , Will J. Handley , Michael P. Hobson , Anthony N. Lasenby

We examine the squeezed limit of the bispectrum when a light scalar with arbitrary non-derivative self-interactions is coupled to the inflaton. We find that when the hidden sector scalar is sufficiently light ($m\lesssim0.1\,H$), the…

宇宙学与河外天体物理 · 物理学 2016-05-10 Béatrice Bonga , Suddhasattwa Brahma , Anne-Sylvie Deutsch , Sarah Shandera