Orateur
Description
In this talk, based on arXiv: 2302.14530, we show how super-Hubble cosmological fluctuations on a flat FLRW background metric can be interpreted as a non-vanishing spatial curvature of the local background metric. The random nature of these fluctuations promotes the curvature density parameter to a stochastic quantity for which we derive novel non-perturbative expressions for its mean, variance, higher moments and full probability distribution. In particular, we provide novel diagrammatic methods to compute and resum the moments of the probability distribution. For scale-invariant Gaussian perturbations, such as those favored by cosmological observations, we find that the most probable value for the curvature density parameter today is -10^{-9}, that its mean is +10^{-9}, both being overwhelmed by a standard deviation of order 10^{-5}.
