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The inflationary paradigm is an important cornerstone of the concordance cosmological model. However, standard inflation cannot fully address the transition from an early homogeneous and isotropic stage, to another one lacking such…

General Relativity and Quantum Cosmology · Physics 2015-12-08 Mauro Mariani , Gabriel R. Bengochea , Gabriel Leon

In this paper we propose a novel unified cosmological model that connects a pre-inflationary epoch, starting at the Planckian time, with the onset of inflation within a single scalar-field framework. The pre-inflationary phase is…

General Relativity and Quantum Cosmology · Physics 2026-05-20 M. Montes , José Edgar Madriz Aguilar , A. Bernal , Diego Allan Reyna

The increasing precision of cosmological datasets is opening up new opportunities to test predictions from cosmic inflation. Here we study the impact of high precision constraints on the primordial power spectrum and show how a new…

Astrophysics · Physics 2010-04-08 Benjamin Gold , Andreas Albrecht

Perturbations from inflation evolve into large scale structure of the late universe, and encode abundant cosmic structure formation physics. We allow freedom in the primordial power spectrum, rather than assuming a power law scale…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-12 Guilherme Brando , Eric V. Linder

We perform a cosmological analysis in which we allow the primordial power spectrum of scalar perturbations to assume a shape that is different with respect to the usual power-law, arising from the simplest models of cosmological inflation.…

Cosmology and Nongalactic Astrophysics · Physics 2016-06-22 Stefano Gariazzo

The Pre-Big Bang cosmology inspired generations of cosmologists in attempts to cure the initial Big Bang singularity using a fundamental length scale as proposed by String Theory. The existence of a phase of collapse/inflation with…

General Relativity and Quantum Cosmology · Physics 2022-07-14 V. Bozza

In inflationary models with minimal amount of gravity waves, the primordial power spectrum of density fluctuations, $A_S^2(k)$, together with the basic cosmological parameters, completely specify the predictions for the cosmic microwave…

Astrophysics · Physics 2009-10-31 Yun Wang , David N. Spergel , Michael A. Strauss

We study an inflationary scenario where thermal inflation is followed by fast-roll inflation. This is a rather generic possibility based on the effective potentials of spontaneous symmetry breaking in the context of particle physics models.…

High Energy Physics - Phenomenology · Physics 2008-11-26 Jinn-Ouk Gong

The vacuum inflation with a boundary condition specified at a short-distance scale in a generally primeval non-flat Universe, and implications of the correspondingly modified primordial power spectrum via the WMAP data are investigated. We…

Astrophysics · Physics 2009-09-28 Jie Ren , Hong-Guang Zhang , Xin-He Meng

The cosmological observations of cosmic microwave background and large-scale structure indicate that our universe has a nearly scaling invariant power spectrum of the primordial perturbation. However, the exact origin for this primordial…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-21 Qing-Yang Wang , Yong Tang , Yue-Liang Wu

I describe the features and general properties of bouncing models and the evolution of cosmological perturbations on such backgrounds. I will outline possible observational consequences of the existence of a bounce in the primordial…

High Energy Physics - Theory · Physics 2009-11-10 Nelson Pinto-Neto

We revisit an inflationary scenario in which primordial inhomogeneities arise from a quantum collapse, a stochastic mechanism described in the context of quantum collapse theories in its continuous version and within semiclassical gravity.…

General Relativity and Quantum Cosmology · Physics 2026-03-04 María Pía Piccirilli , Gabriel León , Rosa-Laura Lechuga-Solis , Daniel Sudarsky

We propose a $\Lambda$-inflation model which explains a large fraction of the COBE signal by cosmic gravitational waves. The primordial density perturbations fulfil both the contraints of large-scale microwave background and galaxy cluster…

Astrophysics · Physics 2011-07-19 V. N. Lukash , E. V. Mikheeva , V. Müller , A. M. Malinovsky

Recently, there has been some interest for building supersymmetric models of double inflation. These models, realistic from a particle physics point of view, predict a broken-scale-invariant power spectrum of primordial cosmological…

High Energy Physics - Phenomenology · Physics 2014-11-17 Julien Lesgourgues

We study the effects of sudden change in the sound velocity on primordial curvature perturbation spectrum in inflationary cosmology, assuming that the background evolution satisfies the slow-roll condition throughout. It is found that the…

Cosmology and Nongalactic Astrophysics · Physics 2011-06-03 Masahiro Nakashima , Ryo Saito , Yu-ichi Takamizu , Jun'ichi Yokoyama

We build upon previous analytical treatments of scalar perturbations in curved inflationary universes to obtain analytical templates for the primordial tensor power spectrum in models with non-zero primordial spatial curvature. These…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-27 Ezra Msolla , Ayngaran Thavanesan

Inflationary scenarios motivated by high-energy physics generically contain a plethora of degrees of freedom beyond the primordial curvature perturbation. The latter interacts in a simple way with what we name "inflationary flavor…

High Energy Physics - Theory · Physics 2023-01-23 Lucas Pinol , Shuntaro Aoki , Sébastien Renaux-Petel , Masahide Yamaguchi

In these lectures I focus on early universe models which can explain the currently observed structure on large scales. I begin with a survey of inflationary cosmology, the current paradigm for understanding the origin of the universe as we…

High Energy Physics - Theory · Physics 2015-05-18 Robert H. Brandenberger

We study a nonsingular bounce inflation model, which can drive the early universe from a contracting phase, bounce into an ordinary inflationary phase, followed by the reheating process. Besides the bounce that avoided the Big-Bang…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Taotao Qiu , Yu-Tong Wang

Slow-roll inflation generically makes several predictions: a flat Universe, primordial adiabatic density perturbations, and a stochastic gravity-wave background. Each inflation model will further predict specific relations between the…

Astrophysics · Physics 2007-05-23 Marc Kamionkowski