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Résumé |
QFT in nearly dS space-times and, more generally, in FRW backgrounds allows us to
describe correlations at the end of inflation. However, how to extract fundamental
physics out of them is still a challange: we do not even know how fundamental
pillars such as causality and unitarity of time evolution constrain them. In this
talk I will report on a recent program that aims to construct quantum mechanical
observables in cosmology directly from first principles without making any
reference to time evolution. Such a formulation, completely independent of any
field-theory notion, is indeed possible, with the cosmological observables having
a first-principle definition in terms of cosmological polytopes, a novel class of
mathematical objects which allow to translate any question on the physics encoded
in the cosmological observables in combinatorial terms. I will show how a novel
set of constraints on the analytic structure of the cosmological observables
emerge from the intrinsic defintion of such objects, as well as the interplay
between flat-space and cosmological processes. |
