Schwinger–Keldysh mechanism in extended quasi-single field inflation

Sheikhahmadi, Haidar

doi:10.1140/epjc/s10052-019-6969-z

Cited by 7 publications

(6 citation statements)

References 111 publications

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“…Whereas the single field canonical versions of inflation could not able to cover all results risen by observations one might seek a modification in inflationary models [26][27][28]. One possible extension for instance is quasi-single field inflation or maybe multiple field inflation [29][30][31], etc.…”

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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“…Now due to homogeneity of the three space, the metric h ab is characterized by a finite number of time functions q α (t), α = 0, 1, 2, ..., n − 1 and the above action can be written in the form of a relativistic point particle with self-interacting potential in a nD curved space-time as [42,43]…”

Section: Quantum Cosmology In the Minisuperspace Approach: A General ...mentioning

confidence: 99%

Noether Symmetry analysis in Chameleon Field Cosmology

Bhaumik,

Dutta,

Chakraborty

2023

Preprint

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This work deals with chameleon field cosmology (a scalar field nonminimally coupled to cold dark matter) in the background of flat Friedmann-Lemaitre-Robertson-Walker (FLRW) space-time. Both classical and quantum cosmology have been investigated using Noether symmetry analysis of the underlying physical system. The Wheeler-DeWitt (WD) equation has been constructed on the minisuperspace and solutions have been obtained using conserved charge.

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“…The most important set of inflationary parameters are then displayed in Table I. One of the most remarkable predictions of the standard inflationary models is to predict the non Gaussianity of the power-spectrum and quantum perturbations due to initial bangs [73][74][75][76][77][78][79][80][81][82][83][84]. Amongst these fluctuations, the scalar perturbations are considered as the cornerstone and the primary seeds leading to large structure formation [38,85].…”

Section: Constraints On the Model With Planck Data Sets And Horizon E...mentioning

confidence: 99%

Inflation in String Field Theory

Sheikhahmadi,

Faizal,

Aghamohammadi

et al. 2020

Preprint

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In this paper, we analyze the inflationary cosmology using string field theory. This is done by using the zero level contribution from string field theory, which is a non-local tachyonic action. We will use the non-local Friedmann equations for this model based on string field theory, and calculate the slow-roll parameters for this model. We will then explicitly obtain the scalar and tensorial power spectrum, their related indices, and the tensor-to-scalar ratio for this model. Finally, we use cosmological data from Planck 2013 to 2018 to constrain the free parameters in this model, and find that string field theory is compatible with them.

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Schwinger–Keldysh mechanism in extended quasi-single field inflation

Cited by 7 publications

References 111 publications

Constant-roll approach to noncanonical inflation

Constant-roll approach to noncanonical inflation

Noether Symmetry analysis in Chameleon Field Cosmology

Inflation in String Field Theory

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