Title: EFTs for early and late time cosmology

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Abstract:
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In this talk we explore two different EFTs for cosmology. The Kaloper-Sorbo EFT is a model for axionic inflation derived from a duality with ever present 4-forms. A priori an infinite sum, we show that the theory can be consistently truncated and ask the question of how well does this truncated EFT fit current and future Planck runs. We furthermore show how deformations of the theory, motivated by vacuum energy sequestering, can effectively open up the parameter space.

In the second half of the talk, we will discuss quintessence and its place within the Swampland programme. We discuss the implications of light states entering the theory in terms of the coincidence problem and provide a toy model EFT to exemplify our findings.