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We show that a contracting universe which bounces due to quantum cosmological effects and connects to the hot big-bang expansion phase, can produce an almost scale invariant spectrum of perturbations provided the perturbations are produced…

高能物理 - 理论 · 物理学 2008-11-26 Patrick Peter , E. J. C. Pinho , Nelson Pinto-Neto

Following our previous paper, Bergeron et al, Smooth quantum dynamics of the mixmaster universe, Phys. Rev. D 92, 061302(R) (2015), concerning the quantization of the vacuum Bianchi IX model and the Born-Huang-Oppenheimer framework, we…

广义相对论与量子宇宙学 · 物理学 2016-06-29 Herve Bergeron , Ewa Czuchry , Jean-Pierre Gazeau , Przemyslaw Malkiewicz

Recently, attempts have been made to understand the apparent near coincidence of the present dark energy and matter energy in terms of a dynamical attractor-like solution for the evolution of a scalar field. In these models the field…

天体物理学 · 物理学 2009-11-06 M. Yahiro , G. J. Mathews , K. Ichiki , T. Kajino , M. Orito

Using the dS/QFT correspondence in the context of inflation allows for the study of interesting, otherwise inaccessible physics. In particular, by studying inflation via its dual field theory at the boundary of the de Sitter space, it may…

宇宙学与河外天体物理 · 物理学 2011-08-08 Mafalda Dias

Cosmological equations for homogeneous isotropic models filled by scalar fields and ultrarelativistic matter are investigated in the framework of gauge theories of gravity. Regular inflationary cosmological models of flat, closed and open…

广义相对论与量子宇宙学 · 物理学 2014-11-17 A. V. Minkevich

We study quasi-matter bounce cosmology in light of Planck cosmic microwave background (CMB) angular anisotropy measurements along with the BICEP2/Keck Array data. We propose a new primordial scalar power spectrum by considering a linear…

宇宙学与河外天体物理 · 物理学 2022-02-08 Mohammad Arab , Mohsen Khorasani

The cosmon field responsible for dynamical dark energy can induce an inflationary period in early cosmology. Details depend on dilatation symmetry breaking terms in its potential and kinetic term that are relevant only during early stages…

宇宙学与河外天体物理 · 物理学 2015-06-15 C. Wetterich

We examine cosmological inflation in a broad family of scalar-tensor models characterized by scalar-dependent non minimal kinetic couplings and Gauss-Bonnet terms. Using a slow roll-approximation, we compute in detail theoretical…

高能物理 - 理论 · 物理学 2026-05-21 A. Belhaj , H. Es-Sobbahi , M. Oualaid , E. Torrente-Lujan

In the hope of avoiding model dependence of the cosmological observables, phenomenological parametrizations of Cosmic Inflation have recently been proposed. Typically, they are expressed in terms of two parameters associated with an…

宇宙学与河外天体物理 · 物理学 2017-01-16 Jerome Martin , Christophe Ringeval , Vincent Vennin

Inflationary cosmology with a preceding nonsingular bounce can lead to changes on the primordial density fluctuations. One significant prediction is that the amplitude of the power spectrum may undergo a jump at a critical scale. In this…

宇宙学与河外天体物理 · 物理学 2012-04-10 Jie Liu , Yi-Fu Cai , Hong Li

The inflationary paradigm enjoys a very wide acceptance in the cosmological community, due in large part to the fact that it is said to "naturally account" for a nearly scale independent power primordial spectrum of fluctuations which is in…

广义相对论与量子宇宙学 · 物理学 2011-03-28 Gabriel Leon , Daniel Sudarsky

If the spatial curvature of the universe is positive, then the curvature term will always dominate at early enough times in a slow-rolling inflationary epoch. This enhances inflationary effects and hence puts limits on the possible number…

广义相对论与量子宇宙学 · 物理学 2015-06-25 G. F. R. Ellis , W. Stoeger , P. McEwan , P. Dunsby

In light of the most recent cosmological observations, we provide new updated constraints on the slow-roll inflation in different extended scenarios beyond the $\Lambda\rm{CDM}$ cosmological model. Along with the usual six parameters, we…

宇宙学与河外天体物理 · 物理学 2021-11-25 Matteo Forconi , William Giarè , Eleonora Di Valentino , Alessandro Melchiorri

In simple inflationary cosmological scenarios the near-exponential growth can be followed by a long period in which the Universe is dominated by the oscillating inflaton condensate. The condensate is initially almost homogeneous, but…

宇宙学与河外天体物理 · 物理学 2020-02-19 Nathan Musoke , Shaun Hotchkiss , Richard Easther

This paper investigates Starobinsky's model of inflation driven by the trace anomaly of conformally coupled matter fields. This model does not suffer from the problem of contrived initial conditions that occurs in most models of inflation…

高能物理 - 理论 · 物理学 2009-10-31 S. W. Hawking , T. Hertog , H. S. Reall

Bouncing models of cosmology, as they arise e.g. in loop quantum cosmology, can be followed by an inflationary phase and generate close-to-scale-invariant fluctuation spectra as observed in the Cosmic Microwave Background (CMB). However,…

宇宙学与河外天体物理 · 物理学 2023-05-12 Bartjan van Tent , Paola C. M. Delgado , Ruth Durrer

We here investigate bulk-viscosity driven quasi de-Sitter inflation, that is, the period of accelerated expansion in the early universe during which $-\dot{H}\ll H^2$, with $H(t)$ being the Hubble expansion rate. We do so in the framework…

广义相对论与量子宇宙学 · 物理学 2024-02-21 Sayantani Lahiri , Luciano Rezzolla

The inflationary scenario has become the paradigm of early universe cosmology, and - in conjuction with ideas from superstring theory - has led to speculations about an "inflationary multiverse". From a point of view of phenomenology, the…

宇宙学与河外天体物理 · 物理学 2012-05-09 Robert Brandenberger

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…

广义相对论与量子宇宙学 · 物理学 2024-11-26 Lucas M. V. Montese , Nelson Yokomizo

Until recently our knowledge of the primordial curvature perturbation was relatively modest. Ever since COBE delivered its map of data we know the scalar spectrum of primordial perturbations is approximately flat, with the power being only…

宇宙学与河外天体物理 · 物理学 2013-09-24 Raquel H. Ribeiro