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Using a semiclassical approach to Gravitoelectromagnetic Inflation (GEMI), we study the origin and evolution of seminal inflaton and electromagnetic fields in the early inflationary universe from a 5D vacuum state. We use simultaneously the…

Cosmology and Nongalactic Astrophysics · Physics 2011-01-27 Federico Agustin Membiela , Mauricio Bellini

We briefly review the arising of an inflationary phase in the Universe evolution in order to discuss an inhomogeneous cosmological solution in presence of a real self interacting scalar field minimally coupled to gravity in the region of a…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Giovanni Imponente

We introduce a numerical method specifically designed for investigating generic multifield models of inflation where a number of scalar fields $\phi^K$ are minimally coupled to gravity and live in a field space with a non-trivial metric…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-14 William Giarè , Mariaveronica De Angelis , Carsten van de Bruck , Eleonora Di Valentino

We develop a theory of nonlinear cosmological perturbations on superhorizon scales for generic single-field inflation. Our inflaton is described by the Lagrangian of the form $W(X,\phi)-G(X,\phi)\Box\phi$ with…

General Relativity and Quantum Cosmology · Physics 2013-06-04 Yu-ichi Takamizu , Tsutomu Kobayashi

We explore the homogeneous background dynamics and the evolution of generated perturbations of cosmological inflation that is driven by multiple scalar fields interacting with a perfect fluid.Then we apply the method to warm inflation…

General Relativity and Quantum Cosmology · Physics 2018-04-04 Yang-Yang Wang , Jian-Yang Zhu , Xiao-Min Zhang

Scalar and tensor perturbations arising in an inflationary braneworld scenario driven by a single scalar field are considered, where the bulk on either side of the brane corresponds to Anti-de Sitter spaces with different cosmological…

Astrophysics · Physics 2009-11-07 Greg Huey , James E. Lidsey

Out-of-equilibrium, non-perturbative, quantum effects significantly modify the standard picture of inflation in a wide class of models including new, natural, and hybrid inflation. We find that the quantum evolution of a single real…

High Energy Physics - Phenomenology · Physics 2010-01-06 D. Cormier , R. Holman

The quantum evolution of a model of the universe with account of two scalar fields ({\it dilaton} and {\it inflaton}) is considered. For this case, the closed and flat models has been examined. It is shown that in both cases the realization…

General Relativity and Quantum Cosmology · Physics 2007-05-23 V. N. Folomeev

An inflationary single field model with a non-trivial kinetic term for the inflaton is discussed. It is shown that it is possible to have large primordial non-gaussianities and large tensor-to-scalar ratio in a simple concrete model with…

Astrophysics · Physics 2008-12-18 Grigoris Panotopoulos

We present a detailed and systematic analysis of the coarse-grained, nonequilibrium dynamics of a scalar inflaton field coupled to a fermion field in the latter stages of the reheating period of inflationary cosmology. We derive coupled…

High Energy Physics - Phenomenology · Physics 2009-10-30 S. A. Ramsey , B. L. Hu , A. M. Stylianopoulos

The gauge-independent invariant approach to investigation of the linear scalar perturbations of inflaton and gravitational fields is developed in self-consistent way. This approach allows to compare various gauges used by other researchers…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Roman S. Pasechnik , Gregory M. Vereshkov

We analyse the dynamics of spinodal decomposition in inflationary cosmology using the closed time path formalism of out of equilibrium quantum field theory combined with the non-perturbative Hartree approximation. In addition to a general…

High Energy Physics - Phenomenology · Physics 2009-10-31 D. Cormier , R. Holman

We present a new, exact scalar field cosmology for which the spectrum of scalar (density) perturbations can be calculated exactly. We use this exact result to the probe the accuracy of approximate calculations of the perturbation spectrum.

Astrophysics · Physics 2009-10-28 Richard Easther

We study the slow-roll inflationary dynamics in a self-gravitating induced gravity braneworld model with bulk cosmological constant. For E \gg M_{5}^{3}/M^{2}_{2} we find important corrections to the four-dimensional Friedmann equation…

General Relativity and Quantum Cosmology · Physics 2009-11-10 E. Papantonopoulos , V. Zamarias

We investigate the descriptions for the observables of inflationary models, in particular, the spectral index of curvature perturbations, the tensor-to-scalar ratio, and the running of the spectral index, in the framework of perfect fluid…

High Energy Physics - Theory · Physics 2014-12-30 Kazuharu Bamba , Shin'ichi Nojiri , Sergei D. Odintsov , Diego Sáez-Gómez

We provide a detailed study of natural inflation with a periodic non-minimal coupling, which is a well-motivated inflationary model that admits an explicit UV completion. We demonstrate that this construction can satisfy the most recent…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-18 Alberto Salvio , Simone Sciusco

We study an effective 4-dimensional scalar-tensor field theory, originated from an underlying brane-bulk warped geometry, to explore the scenario of inflation. It is shown that the inflaton potential naturally emerges from the radion…

Cosmology and Nongalactic Astrophysics · Physics 2014-10-21 Sumit Kumar , Anjan A. Sen , Soumitra SenGupta

Inflation offers a simple model for very early evolution of our Universe and the origin of primordial perturbations on large scales. Over the last 25 years we have become familiar with the predictions of single-field models, but inflation…

Astrophysics · Physics 2008-11-26 David Wands

We embed general $f(R)$ inflationary models in minimal supergravity plus matter, a single chiral superfield $\Phi$, with or without another superfield $S$, via a Jordan frame Einstein+scalar description. In particular, inflationary models…

High Energy Physics - Theory · Physics 2016-02-17 Horatiu Nastase

The evolution of slow--roll inflation in a five--dimensional brane world model with two boundary branes and bulk scalar field is studied. Assuming that the inflationary scale is below the brane tension, we can employ the moduli space…

Astrophysics · Physics 2009-11-10 P. R. Ashcroft , C. van de Bruck , A. -C. Davis