This session will consist of two short talks:
Tays Miranda (University of Jyväskylä)
Title: The stochastic formalism and contracting cosmologies
Abstract: In this talk I will show how quantum field fluctuations give rise to stochastic noise in a cosmological model described by a scalar field with an exponential potential. In particular, I compute these quantum fluctuations in an inflating or contracting cosmology and discuss how they perturb the equation of state on large scales, which can lead to a quantum instability of the classical collapse solution, below the Planck scale in the case of a pressureless collapse. Also I will comment on the issues for the implementation of the stochastic formalism, beyond the inflationary scenario, related to gauge corrections to the amplitude of the stochastic noise and the validity of the separate universe approach.