Nonanalyticity and On-Shell Factorization of Inflation Correlators at All Loop Orders

Understand

The dynamics of quantum fields during cosmic inflation can be probed via their late-time boundary correlators.

• The analytic structure of these boundary correlators contains rich physical information of bulk dynamics, and is also closely related to cosmological collider observables.
• In this work, we study a particular type of nonanalytic behavior, called nonlocal signals, for inflation correlators with massive exchanges at arbitrary loop orders.
• We propose a signal-detection algorithm to identify all possible sources of nonlocal signals in an arbitrary loop graph, and prove that the algorithm is exhaustive.