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During inflation explicit perturbative computations of quantum field theories which contain massless, non-conformal fields exhibit secular effects that grow as powers of the logarithm of the inflationary scale factor. Starobinskii's…

General Relativity and Quantum Cosmology · Physics 2009-11-11 N. C. Tsamis , R. P. Woodard

A double hybrid inflationary scenario in non-minimal supergravity which can predict values of the tensor-to-scalar ratio up to about 0.05 is presented. Larger values of this ratio would require unacceptably large running of the scalar…

High Energy Physics - Phenomenology · Physics 2015-10-27 G. Lazarides , C. Panagiotakopoulos

In this paper a quantum mechanical phase space picture is constructed for coarse-grained free quantum fields in an inflationary Universe. The appropriate stochastic quantum Liouville equation is derived. Explicit solutions for the phase…

General Relativity and Quantum Cosmology · Physics 2009-10-22 Salman Habib

We study primordial perturbations generated from quantum fluctuations of an inflaton based on the formalism of stochastic gravity. Integrating out the degree of freedom of the inflaton field, we analyze the time evolution of the correlation…

High Energy Physics - Theory · Physics 2008-11-26 Yuko Urakawa , Kei-ichi Maeda

One of the key predictions of the standard inflationary paradigm is the quantum mechanical generation of the transverse and traceless tensor fluctuations due to the rapid accelerated expansion of space, which later constitute a stochastic…

General Relativity and Quantum Cosmology · Physics 2025-10-23 Athul K. Soman , Swagat S. Mishra , Mohammed Shafi , Soumen Basak

We extend the formalism of stochastic inflation to the setup of non-attractor inflation with a sound speed $c_s$. We obtain the Langevin equations for the superhorizon perturbations and calculate the stochastic corrections to curvature…

High Energy Physics - Theory · Physics 2020-12-09 Hassan Firouzjahi , Amin Nassiri-Rad , Mahdiyar Noorbala

It is conjectured that inflation, taking account of quantum gravity, leads to a discrete spectrum of cosmological perturbations, instead of the continuous Gaussian spectrum predicted by standard field theory in an unquantized background.…

Astrophysics · Physics 2009-11-10 Craig J. Hogan

Several mechanisms exist for generating a stochastic background of gravitational waves in the period following inflation. These mechanisms are generally classical in nature, with the gravitational waves being produced from inhomogeneities…

Astrophysics · Physics 2008-11-26 Larry R. Price , Xavier Siemens

We provide a formulation of Stochastic Inflation in full general relativity that goes beyond the slow-roll and separate universe approximations. We show how gauge invariant Langevin source terms can be obtained for the complete set of…

General Relativity and Quantum Cosmology · Physics 2024-06-18 Yoann L. Launay , Gerasimos I. Rigopoulos , E. P. S. Shellard

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 develop a stochastic approach to a non de Sitter Universe in a gauge-invariant way and obtain a system of Langevin-type equations which may be considered to be renormalization group equations for the long wave parts of the scalar fields…

High Energy Physics - Theory · Physics 2008-02-03 Boris Spokoiny

This paper investigates the effects of nonvanishing spatial curvature on the propagation of primordial gravitational waves produced during inflation. In particular, we consider tensor perturbations over a homogeneous and isotropic…

Cosmology and Nongalactic Astrophysics · Physics 2023-08-29 Rocco D'Agostino , Matteo Califano , Nicola Menadeo , Daniele Vernieri

We review the prospects for detecting tensor modes generated during inflation by CMB polarization experiments and by searching for a stochastic gravitational wave background with laser interferometers in space. We tackle the following two…

Astrophysics · Physics 2009-11-11 George Efstathiou , Sirichai Chongchitnan

We derive a Higgs inflationary model in the context of holographic cosmology, where we consider a universe filled with a Higgs field non-minimally coupled to gravity in a slow-roll regime. The amplitude of density (scalar) perturbations is…

General Relativity and Quantum Cosmology · Physics 2021-01-28 Aatifa Bargach , Farida Bargach , Mariam Bouhmadi-López , Taoufik Ouali

We investigate small-scale signatures of the inflationary particle content. We consider the case of a light spin-2 particle sourcing primordial gravitational waves by employing an effective field theory description. Upon allowing…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-08 Laura Iacconi , Matteo Fasiello , Hooshyar Assadullahi , David Wands

We present a two stage hybrid inflationary scenario in non-minimal supergravity which can predict values of the tensor-to-scalar ratio of the order of few times 0.01. For the parameters considered, the underlying supersymmetric particle…

High Energy Physics - Phenomenology · Physics 2015-12-09 G. Lazarides , C. Panagiotakopoulos

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

Phase transitions during inflation can generate a stochastic gravitational-wave background that probes primordial physics. We study the detectability and parameter reconstruction of such a signal with a space-based gravitational-wave…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-24 Qingyuan Liang , Chen Yang , Haipeng An , Huai-Ke Guo

The curvaton and the inhomogeneous reheating scenarios for the generation of the cosmological curvature perturbation on large scales represent an alternative to the standard slow-roll scenario where the observed density perturbations are…

Astrophysics · Physics 2009-11-10 L. Pilo , A. Riotto , A. Zaffaroni

We present a review on the state-of-the-art of the mathematical framework known as stochastic inflation, paying special attention to its derivation and giving references for the readers interested on results coming from the application of…

General Relativity and Quantum Cosmology · Physics 2022-06-20 Diego Cruces