Modulus stabilization in higher curvature dilaton gravity

Choudhury, Sayantan; Mitra, Joydip; SenGupta, Soumitra

doi:10.1007/jhep08(2014)004

Cited by 14 publications

(12 citation statements)

References 105 publications

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“…• Source I: One of the source for dilaton exponential potential is string theory, which is appearing in the Category I. Specifically, superstring theory and low energy supergravity models are the theoretical possibilities in string theory [109][110][111][112][113][114][115][116][117][118] where dilaton exponential potential is appearing in the gravity part of the action in Jordan frame and after conformal transformation in Einstein frame such dilaton effective potential is coupled with the matter sector. The most important example is α-attractor which mimics a class of inflationary models in N = 1 supergravity in 4D.…”

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confidence: 99%

COSMOS- $$e'$$ e ′ -soft Higgsotic attractors

Choudhury

2017

Eur. Phys. J. C

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In this work, we have developed an elegant algorithm to study the cosmological consequences from a huge class of quantum field theories (i.e. superstring theory, supergravity, extra dimensional theory, modified gravity, etc.), which are equivalently described by soft attractors in the effective field theory framework. In this description we have restricted our analysis for two scalar fields -dilaton and Higgsotic fields minimally coupled with Einstein gravity, which can be generalized for any arbitrary number of scalar field contents with generalized non-canonical and non-minimal interactions. We have explicitly used R 2 gravity, from which we have studied the attractor and non-attractor phases by exactly computing two point, three point and four point correlation functions from scalar fluctuations using the InIn (Schwinger-Keldysh) and the δN formalisms. We have also presented theoretical bounds on the amplitude, tilt and running of the primordial power spectrum, various shapes (equilateral, squeezed, folded kite or counter-collinear) of the amplitude as obtained from three and four point scalar functions, which are consistent with observed data. Also the results from two point tensor fluctuations and the field excursion formula are explicitly presented for the attractor and non-attractor phase. Further, reheating constraints, scale dependent behavior of the couplings and the dynamical solution for the dilaton and Higgsotic fields are also presented. New sets of consistency relations between two, three and four point observables are also presented, which shows significant deviation from canonical slow-roll models. Additionally, three possible theoretical proposals have presented to overcome the tachyonic instability at the time of late time acceleration. Finally, we have also provided the bulk interpretation from the three and four point scalar correlation functions for completeness.S. Choudhury: Presently working as a Visiting (Post-Doctoral) fellow at DTP, TIFR, Mumbai. a

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confidence: 99%

COSMOS- $$e'$$ e ′ -soft Higgsotic attractors

Choudhury

2017

Eur. Phys. J. C

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“…and for the generalized q = 1/2 case additionally we have to satisfy another constraint: 39) and for the generalized q = 1/2 case we have…”

Section: Unperturbed Evolutionmentioning

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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“…However such quantum corrections are extremely hard to compute as it completely belongs to the hidden sector of the theory dominated by heavy fields [21,22]. In the trans-Planckian regime the classical gravity sector is corrected by incorporating the effect of higher derivative interactions appearing through the modifications to GR which plays significant role in this context [23][24][25][26][27][28]. On the other hand in trans-Planckian regime quantum corrections of matter fields and their interaction between various constituents modify the picture which are appearing through perturbative loop corrections [29][30][31][32].…”

Section: The Effective Potentialmentioning

confidence: 99%