English
Related papers

Related papers: Beta-function formalism for k-essence constant-rol…

200 papers

In this work, we explore the prospect of generalizing the constant-roll condition in canonical inflationary model to non-canonical models. To find a natural generalization, we focus on three manifestations of this condition and construct…

General Relativity and Quantum Cosmology · Physics 2024-05-07 S. Mohammad Ahmadi , Nahid Ahmadi , Mehdi Shokri

Using a particular form of the quantum K-essence scalar field, we show that in the quantum formalism, a fractional differential equation in the scalar field variable, for some epochs in the Friedmann-Lema\^itre-Robertson-Walker (FLRW) model…

General Relativity and Quantum Cosmology · Physics 2023-04-14 J. Socorro , J. Juan Rosales

In this paper we investigate the implications of having a varying second slow-roll index on the canonical scalar field inflationary dynamics. We shall be interested in cases that the second slow-roll can take small values and…

General Relativity and Quantum Cosmology · Physics 2017-05-03 S. D. Odintsov , V. K. Oikonomou

We consider the renormalization group flow equation for the two-dimensional sigma models with the K\"ahler target space. The first-order formulation allows us to treat perturbations in these models as current-current deformations. We…

High Energy Physics - Theory · Physics 2023-12-05 Oleksandr Gamayun , Andrei Losev , Mikhail Shifman

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 the stochastic formalism of inflation beyond the usual slow-roll approximation. We verify that the assumptions on which the stochastic formalism relies still hold even far from the slow-roll attractor. This includes demonstrating…

Cosmology and Nongalactic Astrophysics · Physics 2019-11-05 Chris Pattison , Vincent Vennin , Hooshyar Assadullahi , David Wands

In light of the most recent cosmological observations, we provide new updated constraints on the slow-roll inflation in different extended scenarios beyond the $\Lambda\rm{CDM}$ cosmological model. Along with the usual six parameters, we…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-25 Matteo Forconi , William Giarè , Eleonora Di Valentino , Alessandro Melchiorri

The previously proposed class of phenomenological inflationary models in which the assumption of inflaton slow-roll is replaced by the more general, constant-roll condition is compared with the most recent cosmological observational data,…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-28 Hayato Motohashi , Alexei A. Starobinsky

We study inflation in a model with constant second slow-roll parameter $\eta$. In this case, the Hubble expansion rate equation has analytical solutions describing four possible, nontrivial inflation scenarios. The evolution of the inflaton…

General Relativity and Quantum Cosmology · Physics 2024-07-03 Marko Stojanovic , Neven Bilic , Dragoljub D. Dimitrijevic , Goran S. Djordjevic , Milan Milosevic

We study constant roll inflation systematically. This is a regime, in which the slow roll approximation can be violated. It has long been thought that this approximation is necessary for agreement with observations. However, recently it was…

High Energy Physics - Theory · Physics 2018-02-21 Lilia Anguelova , Peter Suranyi , L. C. Rohana Wijewardhana

We consider a model of two-field inflation, containing an ordinary scalar field and a DBI field. We work beyond the slow-roll approximation, but we assume a separable Hubble parameter. We then derive the form of potential in this framework…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-25 Kourosh Nozari , Kosar Asadi

We study the seemingly duality between large and small $\eta_H$ for the constant-roll inflation with the second slow-roll parameter $\eta_H$ being a constant. In the previous studies, only the constant-roll inflationary models with small…

General Relativity and Quantum Cosmology · Physics 2019-11-01 Qing Gao , Yungui Gong , Zhu Yi

An inflationary scenario driven by a slow rolling homogeneous scalar field whose potential $V(\Phi)$ is given by a generalized exponential function is discussed. Within the {\sl slow-roll} approximation we investigate some of the main…

Astrophysics · Physics 2008-11-26 J. S. Alcaniz , F. C. Carvalho

An appealing feature of inflationary cosmology is the presence of a phase-space attractor, "slow roll", which washes out the dependence on initial field velocities. We investigate the robustness of this property under backreaction from…

General Relativity and Quantum Cosmology · Physics 2021-04-05 Julien Grain , Vincent Vennin

We present and discuss a new approach increasing by orders of magnitude the speed of performing Bayesian inference and parameter estimation within the framework of slow-roll inflation. The method relies on the determination of an effective…

Cosmology and Nongalactic Astrophysics · Physics 2014-06-03 Christophe Ringeval

This paper uses the beta function formalism to extend the analysis of quintessence cosmological parameters to the logarithmic and exponential dark energy potentials. The previous paper (Thompson 2018) demonstrated the formalism using power…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-14 Rodger I. Thompson

In this paper we use two methods to constrain the the canonical single-field slow-roll inflation model. The first method exploits the analytic slow-roll-parameter dependence of primordial perturbations, and the second consists of a…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-17 Jun Li , Guang-Hai Guo

We study inflation driven by the tachyon field in the holographic braneworld by assuming the second slow-roll parameter $\eta$ is constant. The parameter $\eta$ can be either defined by the tachyon scalar field and the Hubble parameter or…

General Relativity and Quantum Cosmology · Physics 2024-09-16 Marko Stojanovic , Neven Bilic , Dragoljub D. Dimitrijevic , Goran S. Djordjevic , Milan Milosevic

The previously introduced class of two-parametric phenomenological inflationary models in General Relativity in which the slow-roll assumption is replaced by the more general, constant-roll condition is generalized to the case of $f(R)$…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-15 Hayato Motohashi , Alexei A. Starobinsky

In this paper, an elegant mathematical approach is introduced to solve the equations of warm inflationary model without using extra approximations other than slow-roll. This important inflationary method known as Hamilton-Jacobian…

General Relativity and Quantum Cosmology · Physics 2020-04-08 R. Saleem , M. Zubair