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We place observational constraints on slow-variation single-field inflationary models by carrying out the cosmological Monte Carlo simulation with the recent data of Planck combined with the WMAP large-angle polarization, baryon acoustic…

Cosmology and Nongalactic Astrophysics · Physics 2013-11-12 Shinji Tsujikawa , Junko Ohashi , Sachiko Kuroyanagi , Antonio De Felice

There is solid theoretical and observational motivation behind the idea of scale-invariance as a fundamental symmetry of Nature. We consider a recently proposed classically scale-invariant inflationary model, quadratic in curvature and…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-25 Chiara Cecchini , Mariaveronica De Angelis , William Giarè , Massimiliano Rinaldi , Sunny Vagnozzi

The standard model of cosmology with nearly Gaussian, isotropic, scale invariant and adiabatic initial conditions describes the cosmological observations well. However, the study of any deviation from the mentioned conditions will open up a…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-31 Mohammad Ansari Fard , Shant Baghram

We study a holographic theory of general spacetimes that does not rely on the existence of asymptotic regions. This theory is to be formulated in a holographic space. When a semiclassical description is applicable, the holographic space is…

High Energy Physics - Theory · Physics 2017-04-12 Yasunori Nomura , Nico Salzetta , Fabio Sanches , Sean J. Weinberg

Based on the Effective Field Theory (EFT) of cosmological perturbations, we explicitly clarify the pathology in nonsingular cubic Galileon models and show how to cure it in EFT with new insights into this issue. With the least set of EFT…

General Relativity and Quantum Cosmology · Physics 2017-06-13 Yong Cai , Hai-Guang Li , Taotao Qiu , Yun-Song Piao

This work is an analytical study of the main differences between classical inflationary effects of a fast-roll regime and imprints of hybrid Loop Quantum Cosmology (LQC) on the primordial power spectrum. Effective LQC solutions of…

General Relativity and Quantum Cosmology · Physics 2021-10-01 Beatriz Elizaga Navascués , Guillermo A. Mena Marugán

It is generally expected that heavy fields are present during inflation, which can leave their imprint in late-time cosmological observables. The main signature of these fields is a small amount of distinctly shaped non-Gaussianity, which…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-05 P. Daniel Meerburg , Moritz Münchmeyer , Julian B. Muñoz , Xingang Chen

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…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-16 Jerome Martin , Christophe Ringeval , Vincent Vennin

This monograph provides a largely self--contained and broadly accessible exposition of two cosmological applications of algebraic quantum field theory (QFT) in curved spacetime: a fundamental analysis of the cosmological evolution according…

General Relativity and Quantum Cosmology · Physics 2015-06-08 Thomas-Paul Hack

An approach to construct cosmological inflation models on the basis of a certain dependence of the scalar field evolution on the e-folds number is considered. The reconstruction of the model background parameters according to the kind of…

General Relativity and Quantum Cosmology · Physics 2025-12-23 Igor V. Fomin , Vladimir L. Glushkov , Evgenii S. Dentsel , Gevorg D. Manucharyan , Vyacheslav A. Sizov

Quintessential inflation provides a unified description of the early and late accelerated phases of the Universe, linking the inflationary epoch to the present-day dark energy-dominated era through a single scalar degree of freedom. In this…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-25 Jamerson Rodrigues , Gabriel Rodrigues , Felipe B. M. dos Santos , Simony Santos da Costa , Jailson Alcaniz

A holographic conformal field theory is dual to semi-classical general relativity in Anti-de Sitter space coupled to matter fields. If the CFT factorizes in the large-$N$ limit, then all couplings in its dual are suppressed by the Planck…

High Energy Physics - Theory · Physics 2023-09-11 Luis Apolo , Alexandre Belin , Suzanne Bintanja , Alejandra Castro , Christoph A. Keller

Non-minimally coupled scalar field models are well-known for providing interesting cosmological features. These include a late time dark energy behavior, a phantom dark energy evolution without singularity, an early time inflationary…

General Relativity and Quantum Cosmology · Physics 2021-09-03 Wompherdeiki Khyllep , Jibitesh Dutta

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…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-25 Matteo Forconi , William Giarè , Eleonora Di Valentino , Alessandro Melchiorri

Cosmic inflation provides a window to the highest energy densities accessible in nature, far beyond those achievable in any realistic terrestrial experiment. Theoretical insights into the inflationary era and its observational probes may…

We contrast the initial condition requirements of various contemporary cosmological models, including inflationary and bouncing cosmologies. Various proposals such as Hartle-Hawking's no boundary, or Tunnelling boundary conditions are…

General Relativity and Quantum Cosmology · Physics 2014-11-17 D. H. Coule

The observable universe is fundamentally inhomogeneous and anisotropic. Quantum description of the generation of these inhomogeneities and anisotropies is ill-understood and unsatisfactory. After providing a brief account of the standard…

General Relativity and Quantum Cosmology · Physics 2024-04-05 Sujoy K. Modak

After a brief summary of general relativity and cosmology, we present the basic concepts underlying inflation, the currently best motivated models for the early Universe. We describe the simplest inflation models, based on a single scalar…

General Relativity and Quantum Cosmology · Physics 2008-11-27 David Langlois

Loop Quantum Gravity (L.Q.G.) is one of the two most promising tentative theory for a quantum description of gravity. When applied to the entire universe, the so-called Loop Quantum Cosmology (L.Q.C.) framework offers microscopical models…

General Relativity and Quantum Cosmology · Physics 2014-11-20 J. Grain

The holographic principle is often (and hastily) attributed to quantum gravity and domains of the Planck size. Meanwhile it can be usefully applied to problems where gravitation effects are negligible and domains of less exotic size. The…

High Energy Physics - Theory · Physics 2017-08-23 B. P. Kosyakov
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