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Résumé |
Inflation has been widely regarded as the most promising scenario to explain our observations of the early
universe. However, in view of the difficulties associated with arriving at a unique model of inflation, it seems
worthwhile to investigate alternative scenarios of the early universe, specifically the so-called bouncing
models. In this talk, I shall discuss the evaluation of three-point functions in a specific inflationary model and
a particular class of bouncing models in order to illustrate the primary differences that can arise between
these two scenarios at the level of the three-point functions. I shall consider the axion monodromy model of
inflation, which involves a canonical scalar field that is governed by a linear potential with superimposed
modulations. I shall discuss the evaluation of the scalar-scalar-tensor cross-correlation in this model and
analytically establish the consistency relation (in the squeezed limit) for this three-point function. I shall then
consider a specific class of bouncing models, namely the matter bounce scenario, and discuss the analytical
evaluation of the tensor modes and the tensor bispectrum in this scenario. Further, I shall show that the
consistency relation corresponding to the tensor bispectrum is violated in the matter bounce. The behavior of
the non-Gaussianities, specifically the three-point functions, generated in the inflationary and bouncing
scenarios can hence be used to compare and contrast between the predictions of these alternative models of
the early universe.
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