Large Scale Power Suppression in a Multifield Landscape

Understand

Power suppression of the cosmic microwave background on the largest observable scales could provide valuable clues about the particle physics underlying inflation.

• Here we consider the prospect of power suppression in the context of the multifield landscape.
• Based on the assumption that our observable universe emerges from a tunnelling event and that the relevant features originate purely from inflationary dynamics, we find that the power spectrum not only contains information on single-field dynamics, but also places strong con- straints on all scalar fields present in the theory.
• We find that the simplest single-field models giving rise to power suppression do not generalise to multifield models in a straightforward way, as the resulting superhorizon evolution of the curvature perturbation tends to erase any power suppression present at horizon crossing.