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In this paper we extend our previous treatment of the one-loop corrections to inflation. Previously we calculated the one-loop corrections to the background and the two-point correlation function of inflaton fluctuations in a specific model…

High Energy Physics - Theory · Physics 2008-11-26 Martin S. Sloth

I show that a classical scalar potential with $ V''/V \sim 1 $ can be sufficiently flattened by quantum corrections to give rise to slow-roll inflation. This provides perhaps the simplest way to generate an inflationary potential without…

High Energy Physics - Phenomenology · Physics 2009-10-28 Ewan D. Stewart

We discuss the principles governing the selection of inflationary models for which preheating can affect the CMB. This is a (fairly small) subset of those models which have non-negligible entropy/isocurvature perturbations on large scales…

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

A new model of inflation is described. An unusual form for the inflationary potential is obtained because the inflaton corresponds to a non-trivial path in the configuration space of the two real scalar fields of the model. The model…

Astrophysics · Physics 2009-10-22 Ewan D. Stewart

We study models of inflation where the inflaton corresponds to a flat direction in field space and its mass term is generated by gravity mediated soft supersymmetry breaking at high scale. Assuming the inflaton to have non negligible…

High Energy Physics - Phenomenology · Physics 2007-05-23 Laura Covi

Small-field inflation typically requires rather special initial conditions to commence. It is proposed that in models where the inflaton is an axionlike field, with a periodic contribution to the potential, there is a possibility of…

Cosmology and Nongalactic Astrophysics · Physics 2010-01-05 Michal Spalinski

Two extensions of ideas lying in the basis of the inflationary scenario of the early Universe and their effect on the large scale structure of the present-day Universe are discussed. The first of them is the possibility of fast phase…

Astrophysics · Physics 2007-05-23 A. A. Starobinsky

We study some of the roles for unparticles in an inflationary universe. Unparticles by themselves are not appropriate for generating the primordial perturbations since their power spectrum does not match what has been inferred from…

High Energy Physics - Phenomenology · Physics 2008-12-18 Hael Collins , R. Holman

With a scalar field non-minimally coupled to curvature, the underlying geometry and variational principle of gravity - metric or Palatini - becomes important and makes a difference, as the field dynamics and observational predictions…

General Relativity and Quantum Cosmology · Physics 2020-08-26 Laur Järv , Alexandros Karam , Aleksander Kozak , Angelos Lykkas , Antonio Racioppi , Margus Saal

We consider "new inflation" inflationary models at small fields, embedded in minimal ${\cal N}=1$ supergravity with a single chiral superfield. Imposing a period of inflation compatible with experiment severely restricts possible models,…

High Energy Physics - Theory · Physics 2016-10-12 Heliudson Bernardo , Horatiu Nastase

In this work we re-investigate pros and cons of mutated hilltop inflation. Applying Hamilton-Jacobi formalism we solve inflationary dynamics and find that inflation goes on along the ${\cal W}_{-1}$ branch of the Lambert function. Depending…

General Relativity and Quantum Cosmology · Physics 2018-05-15 Barun Kumar Pal

We analyse the effect of the non-minimal coupling of the form $\xi\phi^2R/2$ on the single field inflation. If the non-minimal coupling is large, it relaxes the constraint on the field self coupling, making it possible to use the Standard…

High Energy Physics - Phenomenology · Physics 2008-10-20 F. L. Bezrukov

In the context of gauge theories, observable quantities, if properly defined and computed, do not depend on the gauge-fixing procedure. In this paper, we develop a formalism that implements this (apparent) tautology in the case of…

High Energy Physics - Theory · Physics 2020-04-29 Alfredo Urbano

We consider curved space quantum corrections to the equations of motion of the inflaton field in the early Universe. Using the stochastic formalism in phase space, we demonstrate that the quantum corrected evolution of the inflaton can…

High Energy Physics - Phenomenology · Physics 2009-09-25 Zygmunt Lalak , Rudolf Poppe

If the beginning of inflation is defined at the moment when the vacuum energy of the inflaton starts to dominate, the energy density of the other fields at that moment is (by definition) comparable to the inflaton. Although the fraction…

Cosmology and Nongalactic Astrophysics · Physics 2016-02-10 Kazunori Kohri , Chia-Min Lin , Tomohiro Matsuda

We investigate the predictions of inflation models with a non-minimal coupling to gravity for inflationary observables such as the spectral index and tensor-to-scalar ratio in a general setting. We argue that, depending on the relation…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-13 Tatsuki Kodama , Tomo Takahashi

We revisit inflation with non-canonical scalar fields by applying deformed-steepness exponential potentials. We show that the resulting scenario can lead to inflationary observables, and in particular to scalar spectral index and…

General Relativity and Quantum Cosmology · Physics 2021-08-24 Smaragda Lola , Andreas Lymperis , Emmanuel N. Saridakis

We consider an inflationary scenario where the rate of inflaton roll defined by $\ddot\phi/H\dot \phi$ remains constant. The rate of roll is small for slow-roll inflation, while a generic rate of roll leads to the interesting case of…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-09 Hayato Motohashi , Alexei A. Starobinsky , Jun'ichi Yokoyama

We show that the scale of the inflationary potential may be the electroweak scale or even lower, while still generating an acceptable spectrum of primordial density perturbations. Thermal effects readily lead to the initial conditions…

High Energy Physics - Phenomenology · Physics 2011-02-16 Gabriel German , Graham Ross , Subir Sarkar

We derive the general formulae for the the scalar and tensor spectral tilts to the second order for the inflationary models with non-minimally derivative coupling without taking the high friction limit. The non-minimally kinetic coupling to…

General Relativity and Quantum Cosmology · Physics 2017-02-08 Nan Yang , Qin Fei , Qing Gao , Yungui Gong