Patient Observers and Non-perturbative Infrared Dynamics in Inflation
  We have previously derived the effect of soft graviton modes on the quantum
state of de Sitter using spontaneously broken asymptotic symmetries. In the
present paper we reinterpret this effect in terms of particle production and
relate the quantum states with and without soft modes by means of Bogoliubov
transformations. This also enables us to address the much discussed issues
regarding the observability of infrared effects in de Sitter from a new
perspective. While it is commonly agreed that infrared effects are not visible
to a single sub-horizon observer at late times, we argue that the question is
less trivial for a {\it patient observer} who has lived long enough to have a
record of the state before the soft mode was created. Though classically there
is no obstruction to measuring this effect locally, we give several indications
that quantum mechanical uncertainties may censor the effect. We then apply our
methods to find a non-perturbative description of the quantum state pertaining
to the Page time of de Sitter, and derive with these new methods the
probability distribution for the local quantum states of de Sitter and
slow-roll inflation in the presence of long modes. Finally, we use this to
formulate a precise criterion for the existence of eternal inflation in general
classes of slow-roll inflation.
