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Towards Inflation and Accelerating Cosmologies in String-Generated Gravity Models

Ishwaree P Neupane
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Abstract

The string $α^\prime$-correction to the usual Einstein action comprises a Gauss-Bonnet integrand multiplied by non-trivial functions of the modulus field $χ$ and/or the dilaton field $ϕ$. We discuss how the presence of such terms in the four dimensional effective action can explain several novel phenomena, such as a four-dimensional flat Friedmann-Robertson-Walker universe undergoing a cosmic inflation at the early epoch, as well as a cosmic acceleration at late times. The model predicts, during inflation, spectra of both density perturbations and gravitational waves that may fall well within the experimental bounds. The model therefore provides a unified approach for explaining the early and late time accelerating phases of the universe.

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Ishwaree P Neupane. 2006-05-29. Towards Inflation and Accelerating Cosmologies in String-Generated Gravity Models. https://arxiv.org/abs/hep-th/0605265

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