Speaker
Description
In this talk we combine two previously disjointed areas of research, namely multifield cosmological models and effective actions with higher derivative terms. Cosmological models with many scalars are motivated by embeddings in a fundamental theoretical framework and, in addition, they lead to novel phenomena (of interest for both inflation and dark energy) in the rapid turn regime. Higher derivative terms are also theoretically motivated and, furthermore, are holding phenomenological promise, in view of the current observational data regarding the dark energy equation of state. We initiate the study of cosmological models arising from effective actions with both multiple scalars and higher derivative terms, focusing on the Gauss-Bonnet term. Although this is a rather simple example, it already illustrates the occurrence of new features of the rapid-turn regime, which may have interesting phenomenological implications.