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Constant roll inflation is analyzed in the presence of multi scalar fields which are assumed to be described by a constant roll rate each. The different cases are studied and the corresponding potentials are reconstructed. The exact…

General Relativity and Quantum Cosmology · Physics 2021-01-04 Merce Guerrero , Diego Rubiera-Garcia , Diego Saez-Chillon Gomez

Supersymmetric hybrid inflation is an exquisite framework to connect inflationary cosmology to particle physics at the scale of grand unification. Ending in a phase transition associated with spontaneous symmetry breaking, it can naturally…

High Energy Physics - Phenomenology · Physics 2014-07-31 Wilfried Buchmuller , Valerie Domcke , Kohei Kamada , Kai Schmitz

In multifield inflation driven by $d$ scalar fields, $O (d)$ symmetry renders the number of fields irrelevant at classical level. This ceases to be the case once stochastic effects are accommodated. The statistical quantities such as the…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-12 Tomo Takahashi , Koki Tokeshi

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

Assuming a first order phase transition during inflation, a model scenario is described which does not require a tiny coupling constant. Thermal equilibrium is closely maintained as inflation commences. No large scale reheating is…

Astrophysics · Physics 2008-11-26 Arjun Berera

Inflation models can have an early phase of inflation where the evolution of the inflaton is driven by quantum fluctuations before entering the phase driven by the slope of the scalar field potential. For a Coleman-Weinberg potential this…

Cosmology and Nongalactic Astrophysics · Physics 2013-03-06 Arjun Berera , Raghavan Rangarajan

We compute the tensor and scalar spectral index $n_t$, $n_s$, the tensor-to-scalar ratio $r$, the consistency relation $n_t/r$ in the general monomial multifield slow-roll inflation models with potentials $V \sim\sum_i\lambda_i…

Cosmology and Nongalactic Astrophysics · Physics 2017-12-21 Zhong-Kai Guo

We propose a new scenario for early cosmology, where inflationary de Sitter phase dynamically occurs. The effect emerges as a result of dynamics of the topologically nontrivial sectors in expanding universe. Technically the effect can be…

High Energy Physics - Theory · Physics 2014-04-29 Ariel R. Zhitnitsky

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 define a new inflationary scenario in which inflation starts naturally after the Big Bang when the energy density drops below some critical value. As a model, we use recently proposed symmetron field whose effective potential depends on…

Cosmology and Nongalactic Astrophysics · Physics 2014-04-02 Ruifeng Dong , William H. Kinney , Dejan Stojkovic

It is discussed how phase transitions of first order (with phase separation and surface tension), continuous transitions and (multi)-critical points can be defined and classified for finite systems from the topology of the energy surface…

Statistical Mechanics · Physics 2007-05-23 D. H. E. Gross , E. Votyakov

We study the ultra slow roll model in the context of stochastic inflation. Using stochastic $\delta N$ formalism, we calculate the mean number of $e$-folds, the power spectrum, the bispectrum and the stochastic corrections into these…

High Energy Physics - Theory · Physics 2019-01-23 Hassan Firouzjahi , Amin Nassiri-Rad , Mahdiyar Noorbala

The dynamics of a single scalar field which describes a second order phase transition is considered taking into account the thermal effects in the high temperature limit. I conclude that thermal effects play a very important role during…

High Energy Physics - Phenomenology · Physics 2010-11-11 Mauricio Bellini

This paper considers warm inflation as an interesting application of multi-field inflation. Delta-N formalism is used for the calculation of the evolution of the curvature perturbations during warm inflation. Although the perturbations…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-28 Tomohiro Matsuda

We present the first quantum field theory model of inflation that is renormalizable in the matter sector, with a super-Hubble inflaton mass and sub-Planckian field excursions, which is thus technically natural and consistent with a…

High Energy Physics - Phenomenology · Physics 2021-01-11 Mar Bastero-Gil , Arjun Berera , Rudnei O. Ramos , João G. Rosa

The temperature phase transition in the N-component scalar field theory with spontaneous symmetry breaking is investigated in the perturbative approach. The second Legendre transform is used together with the consideration of the gap…

High Energy Physics - Theory · Physics 2009-09-25 M. Bordag , V. Skalozub

We draw attention to the possibility that inflation (i.e. accelerated expansion) might continue after the end of slow roll, during a period of fast oscillations of the inflaton field \phi . This phenomenon takes place when a mild…

General Relativity and Quantum Cosmology · Physics 2009-10-30 Thibault Damour , Viatcheslav F. Mukhanov

It has recently been pointed out that a substantial amount of e-folds can occur during the waterfall regime of hybrid inflation. Moreover, Kodama et.al. have derived analytic approximations for the trajectories of the inflaton and of the…

High Energy Physics - Phenomenology · Physics 2013-05-30 Sébastien Clesse , Björn Garbrecht

We find a unique way of realizing inflation through cyclic phases in an universe with negative vacuum energy. According to the second law of thermodynamics entropy monotonically increases from cycle to cycle, typically by a constant factor.…

High Energy Physics - Theory · Physics 2009-09-02 Tirthabir Biswas , Anupam Mazumdar

It has recently been shown that in single field slow-roll inflation the total volume cannot grow by a factor larger than e^(S_dS/2) without becoming infinite. The bound is saturated exactly at the phase transition to eternal inflation where…

High Energy Physics - Theory · Physics 2015-06-03 Sergei Dubovsky , Leonardo Senatore , Giovanni Villadoro