Towards the physical vacuum of cosmic inflation

Hongliang Jiang,Yi Wang

doi:10.1016/j.physletb.2016.06.069

Abstract

There have been long debates about the initial condition of inflationary perturbations. In this work we explicitly show the decay of excited states during inflation via interactions. For this purpose, we note that the folded shape non-Gaussianity can be interpreted as the decay of the non-Bunch-Davies initial condition. The one loop diagrams with non-Bunch-Davies propagators are calculated to uncover the decay of such excited states. The observed smallness of non-Gaussianity keeps the window open for probing inflationary initial conditions and trans-Planckian physics.

Highlights

There have been long debates about the initial condition of inflationary perturbations
It is argued that only the lowest energy vacuum state is left, known as the Bunch-Davies (BD) vacuum [1]
The non-vacuum initial states for the inflationary perturbations are supported by a number of considerations:

Summary

Introduction

There have been long debates about the initial condition of inflationary perturbations. The non-vacuum initial states for the inflationary perturbations are supported by a number of considerations: If inflation lasts long enough, when tracking back in time, the physical wavelength of any perturbation mode starts shorter than the UV cutoff Λ of the IR effective field theory.

Results

Conclusion