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After the release of the PLANCK data, it is evident that inflationary paradigm has stood the test of time. Even though, it is difficult to realise inflationary paradigm in a particle physics model as the present observations have ruled out…

Cosmology and Nongalactic Astrophysics · Physics 2017-12-29 Suratna Das , Girish Kumar Chakravarty , Gaetano Lambiase , Subhendra Mohanty

Warm Inflation seems to be the most befitting single-field slow-roll inflation scenario in the context of the recently proposed Swampland Criteria. We investigate the constraints these Swampland Criteria impose on Warm Inflation parameters…

High Energy Physics - Theory · Physics 2019-03-27 Suratna Das

We quantify the degree of fine tuning required to achieve an observationally viable period of inflation in the strongly dissipative regime of warm inflation. The ``fine-tuning'' parameter $\lambda$ is taken to be the ratio of the change in…

General Relativity and Quantum Cosmology · Physics 2023-04-03 Gabriele Montefalcone , Vikas Aragam , Luca Visinelli , Katherine Freese

We investigate warm inflationary scenario in which the accelerated expansion of the early Universe is driven by chameleon-like scalar fields. Due to the non-minimal coupling between the scalar field and the matter sector, the…

General Relativity and Quantum Cosmology · Physics 2020-01-01 Haidar Sheikhahmadi , Abolhassan Mohammadi , Ali Aghamohammadi , Tiberiu Harko , Ramón Herrera , Christian Corda , Amare Abebe , Khaled Saaidi

Slow-roll inflation can be studied as an effective field theory. The form of the inflaton potential consistent with the data is V(phi) = N M^4 w(phi/[sqrt{N} M_{Pl}]) where phi is the inflaton field, M is the inflation energy scale, and N ~…

Astrophysics · Physics 2007-05-23 D. Boyanovsky , H. J. de Vega , N. G. Sanchez

In the framework of classical scale invariance, we consider quadratic gravity in the Palatini formalism and investigate the inflationary predictions of the theory. Our model corresponds to a two-field scalar-tensor theory, that involves the…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-28 Ioannis D. Gialamas , Alexandros Karam , Thomas D. Pappas , Vassilis C. Spanos

We revisit the idea that the inflaton may have dissipated part of its energy into a thermal bath during inflation, considering monomial inflationary potentials and three different forms of dissipation rate. Using a numerical Fokker-Planck…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-06 Guillermo Ballesteros , Alejandro Pérez Rodríguez , Mathias Pierre

We show that if the inflaton has a non-minimal coupling to gravity and the Planck scale is dynamically generated, the results of Coleman-Weinberg inflation are confined in between two attractor solutions: quadratic inflation, which is ruled…

High Energy Physics - Phenomenology · Physics 2016-01-18 Kristjan Kannike , Antonio Racioppi , Martti Raidal

We discuss the spectrum of scalar density perturbations from warm inflation when the friction coefficient $\Gamma$ in the inflaton equation is dependent on the inflaton field. The spectral index of scalar fluctuations depends on a new…

Astrophysics · Physics 2009-11-10 Lisa M. H. Hall , Ian G. Moss , Arjun Berera

A safe way to reheat the universe, in models of natural and quadratic inflation, is through shift symmetric couplings between the inflaton $\phi$ and the Standard Model (SM), since they do not generate loop corrections to the potential…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-04 Ricardo Z. Ferreira , Alessio Notari

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

We determine the power spectrum for inflation models covering all regimes from cold (isentropic) to warm (nonisentropic) inflation. We work in the context of the stochastic inflation approach, which can nicely describe both types of…

Cosmology and Nongalactic Astrophysics · Physics 2013-03-27 Rudnei O. Ramos , L. A. da Silva

We consider the robustness of small-field inflation in the presence of scalar field inhomogeneities. Previous numerical work has shown that if the scalar potential is flat only over a narrow interval, such as in commonly considered…

General Relativity and Quantum Cosmology · Physics 2018-09-05 M. C. David Marsh , John D. Barrow , Chandrima Ganguly

We study the problem of initial conditions for slow-roll inflation along a plateau-like scalar potential within the framework of fluctuation-dissipation dynamics. We consider, in particular, that inflation was preceded by a…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-09 Mar Bastero-Gil , Arjun Berera , Robert Brandenberger , Ian G. Moss , Rudnei O. Ramos , Joao G. Rosa

Slow-roll inflation is a successful paradigm. However we find that even a small coupling of the inflaton to other light fields can dramatically alter the dynamics and predictions of inflation. As an example, the inflaton can generically…

High Energy Physics - Phenomenology · Physics 2023-09-19 Kim V. Berghaus , Peter W. Graham , David E. Kaplan

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

The scalar field theory of cosmological inflation constitutes nowadays one of the preferred scenarios for the physics of the early universe. In this paper we aim at studying the inflationary universe making use of a numerical lattice…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-09 Angelo Caravano , Eiichiro Komatsu , Kaloian D. Lozanov , Jochen Weller

We consider a warm inflationary scenario in which the two dominant matter components present in the early Universe, the scalar field, and the radiation fluid, evolve with different four-velocities. This cosmological system is mathematically…

General Relativity and Quantum Cosmology · Physics 2021-03-15 Tiberiu Harko , Haidar Sheikhahmadi

We propose a possibility that the inflaton potential is significantly modified after inflation due to heavy field dynamics. During inflation there may be a heavy scalar field stabilized at a value deviated from the low-energy minimum. As…

High Energy Physics - Phenomenology · Physics 2016-02-24 Naoya Kitajima , Fuminobu Takahashi

We discuss a minimal extension of the Standard Model (SM) where a single real scalar field serves as both inflaton and dark matter. The corresponding Lagrangian contains the renormalizable interactions of the inflaton field. Quantum effects…

High Energy Physics - Phenomenology · Physics 2022-05-30 Jong-Hyun Yoon