Revising the observable consequences of slow-roll inflation

Understand

We study the generation of primordial perturbations in a (single-field) slow-roll inflationary universe.

• In momentum space, these (Gaussian) perturbations are characterized by a zero mean and a non-zero variance $\Delta^2(k, t)$.
• However, in position space the variance diverges in the ultraviolet.
• The requirement of a finite variance in position space forces one to regularize $\Delta^2(k, t)$.