Summary: | The existence of a quasi-deSitter expansion in the early universe, known as inflation, generates the seeds of large-scale structures and is one of the foundations of the standard cosmological model. The main observational predictions from inflation include the existence of a nearly scale-invariant primordial power spectrum that is imprinted on the cosmic microwave background (CMB), which has been corroborated with remarkable precision in recent years. In single-field slow-roll inflation, a field called the inflaton dominates the energy density of the universe and slowly rolls in an almost perfectly flat potential. In addition, the motion of the inflaton field is friction dominated, with its velocity being completely specified by its position in the field space. This basic scenario is known as the slow-roll approximation and its validity is controlled by the magnitude of the so-called slow-roll parameters. Generalizations of single-field slow-roll inflation provide a wealth of observational signatures in the CMB temperature power spectrum, CMB polarization spectrum, primordial non-Guassianity and in lensing reconstruction. This thesis provides a series of consistency checks between these observables that can distinguish slow-roll violations from alternative explanations.
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