New probes of initial state of quantum fluctuations during inflation

This is great, but...
• The proof relies on the following Taylor expansion:
• ζL = 0 + ζL [d0/dζL]
• Perhaps it is interesting to show this explicitly using the in-in
formalism.
• Such a calculation would shed light on the limitation of the
above Taylor expansion.
• Indeed it did - we found a non-trivial “counterexample”
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