Warm Tachyonic Inflation in a Warped Background

Deshamukhya, Atri; Panda, Sudhakar

doi:10.1142/s0218271809016168

Cited by 36 publications

(18 citation statements)

References 41 publications

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“…16 GeV and k 0 = 0.002M pc −1 [8], the value of R is obtained as R = 0.0091596 which is well within the observational limit . FIG.4 shows the variation of R with respect to the model parameter p. Single field inflation models broadly predict Gaussian primordial density fluctuations.…”

Section: (D) Tensor To Scalar Ratiosupporting

confidence: 79%

“…One of the basic features of warm inflationary scenario is that the production of radiation during inflation influences the seeds of density fluctuations and in high dissipative regime, the density perturbation is expressible as [8] δ H = 16π 5…”

Section: A Perturbation Spectrummentioning

confidence: 99%

“…If this viscosity is large enough, the inflaton will reach a slow-roll regime, where its dynamics becomes over-damped. This over damping is efficient to get the correct number of e-folds before the end of inflation [8]. The inclusion of thermal effects acts similar to a mass term which breaks the scale-symmetry of the zero-temperature theory [9].…”

Section: Introductionmentioning

confidence: 99%

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Geometric Tachyon and Warm Inflation

Bhattacharjee

Deshamukhya

2013

Mod. Phys. Lett. A

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The inflationary models developed in presence of a background radiation can be a solution to the reheating problem faced by common cold (isentropic) inflationary scenario. A D-brane system comprising of k Neuvo-Schwarz(NS) 5-branes with a transverse circle and BPS D3-branes with world volume parallel to the NS 5-branes, placed at a point on the transverse circle diametrically opposite to the NS 5 branes has a point of unstable equilibrium and the D3 brane has a geometric tachyonic mode associated with displacement of the brane along the circle. Cold inflationary scenario has been studied in connection with this geometric tachyon [1] where it was found that one needs a background of minimum 10 4 branes to realize a viable inflationary model. In this piece of work, we have tried to study a model of inflation driven by this geometric tachoyn in presence of radiation. We have found that compared to the isentropic scenario, to satisfy the observational bounds, the number of background branes required in this case reduces drastically and a viable model can be obtained with even six to seven NS 5-branes in the background. In this context, we have also analyzed the non-gaussianity associated with the model and observed that the concerned parameter lies well within the observation limit.

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Section: (D) Tensor To Scalar Ratiosupporting

confidence: 79%

Section: A Perturbation Spectrummentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Geometric Tachyon and Warm Inflation

Bhattacharjee

Deshamukhya

2013

Mod. Phys. Lett. A

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“…[57][58][59][60][61][62][63][64][65][66][67][68][69][70][71][72][73]. The cosmological implications of the tachyon were studied in [74][75][76][77][78][79][80][81][82][83][84][85][86]. For more details see also Refs.…”

Section: Introductionmentioning

confidence: 99%

COSMOS-e’-GTachyon from string theory

Choudhury

Panda

2016

Eur. Phys. J. C

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In this article, our prime objective is to study the inflationary paradigm in the context of the generalized tachyon (GTachyon) living on the world volume of a non-BPS string theory. The tachyon action is considered here is modified compared to the original action. One can quantify the amount of the modification via a power q instead of 1/2 in the effective action. Using this set-up we study inflation by various types of tachyonic potentials, using which we constrain the index q within, 1/2 < q < 2, and a specific combination (∝ α M 4 s /g s ) of the Regge slope α , the string coupling constant g s and the mass scale of tachyon M s , from the recent Planck 2015 and Planck+BICEP2/Keck Array joint data. We explicitly study the inflationary consequences from single field, assisted field and multi-field tachyon set-ups. Specifically for the single field and assisted field cases we derive the results in the quasi-de Sitter background in which we will utilize the details of cosmological perturbations and quantum fluctuations. Also we derive the expressions for all inflationary observables using any arbitrary vacuum and the Bunch-Davies vacuum. For the single field and the assisted field cases we derive the inflationary flow equations, new sets of consistency relations. Also we derive the field excursion formula for the tachyon, which shows that assisted inflation is on the safe side compared to the single field case to validate the effective field theory framework. Further we study the features of the CMB angular power spectrum from TT, TE and EE correlations from scalar fluctuations within the allowed range of q for each of the potentials from the single field set-up. We also put constraints from the temperature anisotropy and polarization spectra, which shows that our analysis is consistent with the Planck 2015 data. Finally, using the δ N formalism we derive Sayantan Choudhury: Presently working as a Visiting (Post-Doctoral) fellow at DTP, TIFR, Mumbai On lien from Harish

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“…For later works, see [9] and [24] and references in these articles. Further developments are found in the articles [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43].…”

Section: Introductionmentioning

confidence: 99%

Warm Inflation

Grøn

2016

Universe

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I show here that there are some interesting differences between the predictions of warm and cold inflation models focusing in particular upon the scalar spectral index n s and the tensor-to-scalar ratio r. The first thing to be noted is that the warm inflation models in general predict a vanishingly small value of r. Cold inflationary models with the potential V = M 4 (φ/M P ) p and a number of e-folds N = 60 predict δ nsC ≡ 1 − n s ≈ (p + 2) /120, where n s is the scalar spectral index, while the corresponding warm inflation models with constant value of the dissipation parameter Γ predict δ nsW = [(20 + p) / (4 + p)] /120. For example, for p = 2 this gives δ nsW = 1.1δ nsC . The warm polynomial model with Γ = V seems to be in conflict with the Planck data. However, the warm natural inflation model can be adjusted to be in agreement with the Planck data. It has, however, more adjustable parameters in the expressions for the spectral parameters than the corresponding cold inflation model, and is hence a weaker model with less predictive force. However, it should be noted that the warm inflation models take into account physical processes such as dissipation of inflaton energy to radiation energy, which is neglected in the cold inflationary models.

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Warm Tachyonic Inflation in a Warped Background

Cited by 36 publications

References 41 publications

Geometric Tachyon and Warm Inflation

Geometric Tachyon and Warm Inflation

COSMOS-e’-GTachyon from string theory

Warm Inflation

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