Soft Theorems For Shift-Symmetric Cosmologies

Understand

We derive soft theorems for single-clock cosmologies that enjoy a shift symmetry.

• These so-called consistency conditions arise from a combination of a large diffeomorphism and the internal shift-symmetry and fix the squeezed limit of all correlators with a soft scalar mode.
• As an application, we show that our results reproduce the squeezed bispectrum for Ultra-slow-roll inflation, a particular shift-symmetric, non-attractor model which is known to violate Maldacena's consistency relation.
• Similar results have been previously obtained by Mooij and Palma using background-wave methods.