Hamilton-Jacobi formalism to warm inflationary scenario

Sayar, K.; Mohammadi, Abolhassan; Akhtari, L.; Saaidi, Kh.

doi:10.1103/physrevd.95.023501

Cited by 36 publications

(29 citation statements)

References 47 publications

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“…But this model faced a problem to justify the smooth exit of the end of inflation. To solve this fatal problem many models of inflation have been put forward such as new inflation [2,3], chaotic inflation [4], k-inflation [6,7], brane inflation [8,9], G-inflation [10][11][12][13] warm inflation [14][15][16][17][18][19][20], etc. Inflation is assumed to be a phase of a very rapid accelerated expansion of the super high energy Universe.…”

Section: Introductionmentioning

confidence: 99%

Constant-roll approach to noncanonical inflation

2019

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The scenario of constant-roll inflation in the frame work of a non-canonical inflaton model will be studied. Both of these modifications lead to appearance of some differences in the slow-roll parameters besides the Friedmann equations resulted in a better justification of theoretical predictions comparing to the observation. Phenomenologically, by assuming a constant η, i.e. second slow roll parameter, and recalculating the related perturbation equations obviously there should appear some modification in the scalar spectral index and amplitude of scalar perturbations. It will be shown that finding an exact solution for Hubble parameter is one of the main advantages and triumphs of this approach. Also, whereas making a connection between sub-horizon and superhorizon regions has a crucial role in inflationary studies the main perturbation parameters will be obtained at the horizon crossing time. To examine the accuracy of our results we shall consider the Planck 2018 results as a confident criterion. To do so by virtue of the r − n s diagram, the acceptable ranges of the free parameters of the model will be illustrated. As a result it will be found out the second slow-roll parameter should be a positive constant and smaller than unity. By constraining the free parameters of the model, also the energy scale of inflation will be estimated that is of order 10 −2 . Even more, by investigating the attractor behavior of the model it will be cleared that the aforementioned properties could be appropriately satisfied.

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Section: Introductionmentioning

confidence: 99%

Constant-roll approach to noncanonical inflation

2019

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“…For a representative list of recent references see Refs. [36][37][38][39][40][41][42][43][44][45]. The dissipative effect arises from a friction term or dissipative coefficient , which describes the processes of the scalar field dissipating into a thermal bath via its interaction with other field degrees of freedom.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of warm power-law plateau inflation with a generalized inflaton decay rate: predictions and constraints after Planck 2015

Jawad¹,

Videla²,

Gulshan³

2017

Eur. Phys. J. C

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In the present work, we study the consequences of considering a new family of single-field inflation models, called power-law plateau inflation, in the warm inflation framework. We consider the inflationary expansion is driven by a standard scalar field with a decay ratio having a generic power-law dependence with the scalar field φ and the temperature of the thermal bath T given by. Assuming that our model evolves according to the strong dissipative regime, we study the background and perturbative dynamics, obtaining the most relevant inflationary observable as the scalar power spectrum, the scalar spectral index and its running and the tensor-toscalar ratio. The free parameters characterizing our model are constrained by considering the essential condition for warm inflation, the conditions for the model evolves according to the strong dissipative regime and the 2015 Planck results through the n s -r plane. For completeness, we study the predictions in the n s -dn s /d ln k plane. The model is consistent with a strong dissipative dynamics and predicts values for the tensor-to-scalar ratio and for the running of the scalar spectral index consistent with current bounds imposed by Planck and we conclude that the model is viable.

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“…where M 2 p = 1 8πG is the well-known reduced Planck mass and is of order of 10 18 GeV . The evolution equation of scalar field in warm inflation can be expressed as (Berera 1996(Berera , 1997(Berera , 2000Berera et al 2009;Sayar et al 2017)…”

Section: General Framworkmentioning

confidence: 99%

“…In this regime, similar to the weak case, to specify scalar power spectrum we consider the Eq. ( 11) but here δφ 2 ≃ k F T /2π 2 where k F = √ ΓH and it can be appeared as follows (Herrera et al 2015;Sayar et al 2017):…”

Section: Consistency Of Power-law Potential In Strong Dissipative Regimementioning

confidence: 99%

Constraints on warm power-law inflation in light of Planck results

Ghadiri¹,

Refaei²,

Aghamohammadi³

et al. 2018

Preprint

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The constraints on a general form for powerlaw potential in the framework of warm single field inflation by means of Planck 2013 and 2015 will be investigated. By considering much less dynamic universe, quasi-static evolutions, and also the well-known slowroll conditions the regions which a binary of our free parameters are in good agreement with Planck results will be obtained. The advantage of this likelihood method is that instead of a set of free parameters we can visualize a region of free parameters that can satisfy the precision limits on theoretical results. On the other side, when we consider the preformed quantity for the amplitude of scalar perturbations the conflict between obtained results for free parameters in different steps dramatically decreased. As done in flagship literature, based on the friction of the environment, we can divide the primordial universe into two different epochs namely weak and strong dissipative regimes. For the aforementioned eras, the free parameters of the model will be constrained and the best regions will be obtained. To do so the main inflationary observables such as tensor-to-scalar ratio, power-spectra of density perturbations and gravitational waves, scalar and tensor

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Hamilton-Jacobi formalism to warm inflationary scenario

Cited by 36 publications

References 47 publications

Constant-roll approach to noncanonical inflation

Constant-roll approach to noncanonical inflation

Dynamics of warm power-law plateau inflation with a generalized inflaton decay rate: predictions and constraints after Planck 2015

Constraints on warm power-law inflation in light of Planck results

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