On the Physical Significance of Infra-red Corrections to Inflationary Observables

Abstract

Inflationary observables, like the power spectrum, computed at one- and higher-order loop level seem to be plagued by large infra-red corrections. In this short note, we point out that these large infra-red corrections appear only in quantities which are not directly observable. This is in agreement with general expectations concerning infra-red effects.

Figures (5)

• Figure 1: The appropriate time contour $C$.
• Figure 2: The cubic vertices with the proper signs $+$ and $-$.
• Figure 3: The diagram contributing to the one-loop two-point correlation function. To each vertex the signs $+$ and $-$ should be attached to each vertex according to the correlator one wishes to compute.
• Figure 4: The diagrams contributing to the two-loop two-point correlation function. To each vertex the signs $+$ and $-$ should be attached to each vertex according to the correlator one wishes to compute.
• Figure 5: The RG equation for the two-point correlation function.