Cosmological evolution in a two-brane warped geometry model

Sumit Kumar,Anjan A Sen,Soumitra Sengupta

doi:10.1016/j.physletb.2015.06.014

Sumit Kumar, Anjan A Sen + Show 1 more

Open Access

https://doi.org/10.1016/j.physletb.2015.06.014

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Abstract

We study an effective 4-dimensional scalar–tensor field theory, originated from an underlying brane–bulk warped geometry, to explore the scenario of inflation. It is shown that the inflaton potential naturally emerges from the radion energy–momentum tensor which in turn results in an inflationary model of the Universe on the visible brane that is consistent with the recent results from the Planck's experiment. The dynamics of modulus stabilization from the inflaton rolling condition is demonstrated. The implications of our results in the context of recent BICEP2 results are also discussed.

Highlights

The standard cosmological paradigm, while successful in describing our observable Universe, is plagued with horizon and flatness problems
Inflationary models are at present the only way to provide solutions for these shortcomings in standard cosmology [1]
According to this paradigm, the Universe at an early epoch experienced an exponentially rapid expansion for a very brief period due to some apparently repulsive gravity-like force. Such a scenario can successfully address the horizon and flatness problems but at the same time, provides a theoretical set up to produce the primordial fluctuations which later may act as a seed for large scale structure formation in the Universe

Summary

INTRODUCTION

The standard cosmological paradigm, while successful in describing our observable Universe, is plagued with horizon and flatness problems. According to this paradigm , the Universe at an early epoch experienced an exponentially rapid expansion for a very brief period due to some apparently repulsive gravity-like force Such a scenario can successfully address the horizon and flatness problems but at the same time, provides a theoretical set up to produce the primordial fluctuations which later may act as a seed for large scale structure formation in the Universe. The stabilisation requirements put further constrains on various parameters of the modulus/scalar potential After deriving these constraints we study the cosmological evolution in the Einstein frame in presence of such a potential and show that it gives a viable model for inflation with required number of e-folds (to solve the horizon and flatness problem) and gives a primordial fluctuations which is perfectly consistent with the Planck results.

LOW ENERGY EFFECTIVE GRAVITY IN PRESENCE OF CURVED BRANES

CONSTRAINTS ON THE FORM OF THE POTENTIAL

INFLATION

1: Behaviour of the potential for

BICEP2 RESULTS FOR GRAVITY WAVES

CONCLUSION