Model Independent Signatures of New Physics in the Inflationary Power Spectrum

TL;DR

This paper calculates universal corrections to the inflationary power spectrum caused by high-energy physics, revealing modifications at order H/M that could be observed in future cosmological data.

Contribution

It introduces a method to derive generic high-energy corrections to the inflationary power spectrum using the in-in formalism, applicable in time-dependent backgrounds.

Findings

Power spectrum universally modified at order H/M

Corrections are qualitatively different from time-independent cases

Potential observability in upcoming cosmological observations

Abstract

We compute the universal generic corrections to the inflationary power spectrum due to unknown high-energy physics. We arrive at this result via a careful integrating out of massive fields in the "in-in" formalism yielding a consistent and predictive low-energy effective description in time-dependent backgrounds. We find that the power spectrum is universally modified at order H/M, where H is the scale of inflation. This is qualitatively different from the universal corrections in time-independent backgrounds, and it suggests that such effects may be present in upcoming cosmological observations.