Abstract
We study the tensor spectral index and the tensor-to-scalar ratio in the simplest multifield extension to single-field, slow-roll inflation models. We show that multifield models with potentials have different predictions for than single-field models, even when all the couplings are equal , due to the probabilistic nature of the fields’ initial values. We analyze well-motivated prior probabilities for the and initial conditions to make detailed predictions for the marginalized probability distribution of . With fields and , we find that differs from the single-field result of at the level. This gives a novel and testable prediction for the simplest multifield inflation models.
- Received 15 September 2014
DOI:https://doi.org/10.1103/PhysRevLett.114.031301
© 2015 American Physical Society