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Trapped inflation is a mechanism in which particle production from the moving inflaton is the main source of friction in the inflaton equation of motion. The produced fields source inflaton perturbations, which dominate over the vacuum…

Cosmology and Nongalactic Astrophysics · Physics 2016-12-09 Lauren Pearce , Marco Peloso , Lorenzo Sorbo

In this work, we investigate the post-inflationary dynamics of a simple single-field model with a renormalizable inflaton potential featuring a near-inflection point at a field value $\phi_0$. Due to the concave shape of the scalar…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-24 Manuel Drees , Chenhuan Wang

Generalized slow roll conditions and parameters are obtained for a general form of scalar-tensor theory (with no external sources), having arbitrary functions describing a nonminimal gravitational coupling F(\phi), a Kahler-like kinetic…

General Relativity and Quantum Cosmology · Physics 2009-11-07 J. R. Morris

We discuss inflaton decays and reheating in no-scale Starobinsky-like models of inflation, calculating the effective equation-of-state parameter, $w$, during the epoch of inflaton decay, the reheating temperature, $T_{\rm reh}$, and the…

High Energy Physics - Phenomenology · Physics 2015-08-06 John Ellis , Marcos A. G. Garcia , Dimitri V. Nanopoulos , Keith A. Olive

We have considered the Yukawa theory at two loop in the inflationary de Sitter spacetime, for a massless minimally coupled scalar and a massless fermion. The one loop computation for the same has been investigated in detail in the earlier…

High Energy Physics - Theory · Physics 2026-04-21 Sourav Bhattacharya , Moutushi Dutta Choudhury

We investigate inflationary particle production associated with a spectator ultralight scalar field, which has been recently proposed as a plausible dark matter candidate. In this framework, we select the Starobinsky potential to drive the…

High Energy Physics - Theory · Physics 2025-02-24 Alessio Belfiglio , Orlando Luongo

In this work, we analyze two possible alternative and model-independent approaches to describe the inflationary period. The first one assumes a general equation of state during inflation due to Mukhanov, while the second one is based on the…

Cosmology and Nongalactic Astrophysics · Physics 2015-04-29 Lotfi Boubekeur , Elena Giusarma , Olga Mena , Héctor Ramírez

We study single field slow-roll inflation in the presence of $F(R)$ gravity in the Palatini formulation. In contrast to metric $F(R)$, when rewritten in terms of an auxiliary field and moved to the Einstein frame, Palatini $F(R)$ does not…

General Relativity and Quantum Cosmology · Physics 2022-07-12 Christian Dioguardi , Antonio Racioppi , Eemeli Tomberg

In this work we terminate inflation during a phase of Constant Roll by means of a waterfall field coupled to the inflaton and a spectator field. The presence of a spectator field means that inflation does not end at a single point,…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-20 Ashley Wilkins , Archie Cable

How is the production of primordial black holes (PBHs) in single-field models of inflation impacted by the presence of additional scalar fields? We consider the effect of a spectator field - a free scalar field with sub-Hubble mass, no…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-05 Dario L. Lorenzoni , Sarah R. Geller , David I. Kaiser , Evan McDonough

We study an inflation mechanism based on attractor properties in cosmological evolutions of a spatially flat Friedmann-Robertson-Walker spacetime based on the Einstein-scalar field theory. We find a new way to get the Hamilton-Jacobi…

General Relativity and Quantum Cosmology · Physics 2013-12-10 Hyeong-Chan Kim

We reexamine inflation due to a constrained inflaton in the model of a complex scalar. Inflaton evolves along a spiral-like valley of special scalar potential in the scalar field space just like single field inflation. Sub-Planckian…

High Energy Physics - Phenomenology · Physics 2015-12-02 Romy H. S. Budhi , Shoichi Kashiwase , Daijiro Suematsu

In this study, we explore the back reaction of phase transitions in the spectator sector on the inflaton field during slow-roll inflation. Due to the significant excursion of the inflaton field, these phase transitions are likely to occur…

High Energy Physics - Phenomenology · Physics 2024-11-20 Haipeng An , Qi Chen , Yuhang Li , Yuan Yin

We study post-inflationary evolution in $\alpha$-attractor T-models of inflation. We consider the dynamics of both scalar fields present in these models: the inflaton and the spectator, as a negative field-space curvature may lead to…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-12 Tomasz Krajewski , Krzysztof Turzyński

Quantum fluctuations of an inflaton field, slow-rolling during inflation are coupled to metric fluctuations. In conventional four dimensional cosmology one can calculate the effect of scalar metric perturbations as slow-roll corrections to…

High Energy Physics - Theory · Physics 2009-11-11 Kazuya Koyama , Shuntaro Mizuno , David Wands

We explore the inflationary phase of a scalar field with a kinetic term non-minimally coupled to gravity. We find that one of the slow-roll conditions is naturally consequence of the equation of motion of the scalar field. Thus, slow-roll…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-16 Amir Ghalee

The Friedmann-Robertson-Walker (FRW) cosmology is analyzed with a general potential $\rm V(\phi)$ in the scalar field inflation scenario. The Bohmian approach (a WKB-like formalism) was employed in order to constraint a generic form of…

General Relativity and Quantum Cosmology · Physics 2019-05-01 Omar E. Núñez , J. Socorro , Rafael Hernández-Jiménez

We consider the effect of the Gibbons-Hawking radiation on the inflaton in the situation where it is coupled to a large number of spectator fields. We argue that this will lead to two important effects - a thermal contribution to the…

General Relativity and Quantum Cosmology · Physics 2018-05-03 Malcolm Fairbairn , Tommi Markkanen , David Rodriguez-Roman

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 study inflation driven by a slow-rolling inflaton field, characterised by a quadratic potential, and incorporating radiative corrections within the context of supergravity. In this model the energy scale of inflation is not overly…

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