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We analyse the evolution of the reduced density matrix of inflationary perturbations, coupled to a heavy entropic field via the leading-order term within the Effective Field Theory of Inflation, for two nearly de Sitter backgrounds. We…

High Energy Physics - Theory · Physics 2024-11-14 Suddhasattwa Brahma , Jaime Calderón-Figueroa , Xiancong Luo , David Seery

We investigate in detail the attractor behavior of some inflationary models based on braneworld dynamics under the constant-roll condition. We describe the dynamics of the models, assuming that the second slow-roll parameter remains…

General Relativity and Quantum Cosmology · Physics 2025-04-29 Goran S. Djordjevic , Neven Bilić , Dragoljub D. Dimitrijevic , Milan Milosevic , Marko Stojanovic

Quantum fast-roll initial conditions for the inflaton which are different from the classical fast-roll conditions and from the quantum slow-roll conditions can lead to inflation that last long enough. These quantum fast-roll initial…

Astrophysics · Physics 2009-01-01 F. J. Cao , H. J. de Vega , N. G. Sanchez

We analyse field fluctuations during an Ultra Slow-Roll phase in the stochastic picture of inflation and the resulting non-Gaussian curvature perturbation, fully including the gravitational backreaction of the field's velocity. By working…

General Relativity and Quantum Cosmology · Physics 2021-10-04 Tomislav Prokopec , Gerasimos Rigopoulos

We present a stable cosmological model of a closed universe in the presence of conventional scalar field. The stability of the model and absence of singularity is ensured by spatial curvature without the need for additional peculiar matter.…

General Relativity and Quantum Cosmology · Physics 2025-04-29 Rinat Kagirov

We consider low scale slow roll inflation driven by the gauge invariant flat directions {\bf udd} and {\bf LLe} of the Minimally Supersymmetric Standard Model at the vicinity of a saddle point of the scalar potential. We study the stability…

High Energy Physics - Phenomenology · Physics 2010-10-27 Rouzbeh Allahverdi , Kari Enqvist , Juan Garcia-Bellido , Asko Jokinen , Anupam Mazumdar

We propose a class of single-field, slow-roll inflation models in which a typical number of $e$-folds can be extremely large. The key point is to introduce a very shallow local minimum near the top of the potential in a hilltop inflation…

High Energy Physics - Phenomenology · Physics 2019-12-16 Naoya Kitajima , Yuichiro Tada , Fuminobu Takahashi

We study the problem of obtaining de Sitter and inflationary vacua from dimensional reduction of double field theory (DFT) on nongeometric string backgrounds. In this context, we consider a new class of effective potentials that admit…

High Energy Physics - Theory · Physics 2016-05-05 Falk Hassler , Dieter Lust , Stefano Massai

In this paper we illustrate an interesting example of low scale inflation with an extremely large number of e-foldings. This realization can be implemented easily in hybrid inflation model where usually inflation ends via phase transition.…

High Energy Physics - Theory · Physics 2007-05-23 Anupam Mazumdar

Anisotropic and isotropic slow-roll inflation supported by n-forms are sought. Canonical field strengths and their duals are taken into account, and they are allowed to have a potential and also, when necessary for slow-roll, a nonminimal…

Cosmology and Nongalactic Astrophysics · Physics 2009-09-24 Tomi S. Koivisto , David F. Mota , Cyril Pitrou

We examine the covariant properties of generalized models of two-field inflation, with non-canonical kinetic terms and a possibly non-trivial field metric. We demonstrate that kinetic-term derivatives and covariant field derivatives do…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-28 Eleftheria Tzavara , Shuntaro Mizuno , Bartjan van Tent

Ultra slow-roll inflation has recently been used to challenge the non-Gaussianity consistency relation. We show that this inflationary scenario belongs to a one parameter class of models and we study its properties and observational…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 Jerome Martin , Hayato Motohashi , Teruaki Suyama

We investigate the dynamics of homogeneous phase space for single-field models of inflation. Inflationary trajectories are formally attractors in phase space, but since in practice not all initial conditions lead to them, some degree of…

High Energy Physics - Theory · Physics 2014-11-20 Paul Franche , Rhiannon Gwyn , Bret Underwood , Alisha Wissanji

We revisit the status of hybrid inflation in the light of Planck and recent BICEP2 results, taking care of possible transient violations of the slow-roll conditions as the field passes from the large field to the vacuum dominated phase. The…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-05 Sebastien Clesse , Jeremy Rekier

Inflation may occur while rolling into the metastable supersymmetry-breaking vacuum of massive supersymmetric QCD. We explore the range of parameters in which slow-roll inflation and long-lived metastable supersymmetry breaking may be…

High Energy Physics - Theory · Physics 2008-11-26 Nathaniel J. Craig

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

We show explicitly some exciting features of double-inflation: (i) it can often lead to strongly correlated adiabatic and entropy (isocurvature) power spectra. (ii) The two-field slow-roll consistency relations can be violated when the…

Astrophysics · Physics 2009-11-07 Shinji Tsujikawa , David Parkinson , Bruce A. Bassett

Slow roll reconstruction is derived from the Hamilton-Jacobi formulation of inflationary dynamics. It automatically includes information from sub-leading terms in slow roll, and facilitatesthe inclusion of priors based on the duration on…

Astrophysics · Physics 2009-06-23 Peter Adshead , Richard Easther

We study slow-roll inflation model controlled by the modular flavor symmetry. In the model, the modulus field plays a role of inflaton and the introduction of the stabilizer field coupled to a modular form in the superpotential produces the…

High Energy Physics - Phenomenology · Physics 2023-07-26 Yoshihiko Abe , Tetsutaro Higaki , Fumiya Kaneko , Tatsuo Kobayashi , Hajime Otsuka

Many alternatives to canonical slow-roll inflation have been proposed over the years, one of the main motivations being to have a model, capable of generating observable values of non-Gaussianity. In this work, we (re-)explore the physical…

High Energy Physics - Theory · Physics 2016-07-06 David Pirtskhalava , Luca Santoni , Enrico Trincherini
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