Séminaires et colloques

The primordial universe as a quantum lab

by Julien Grain (IAS)

Grand Amphithéâtre (LPSC)

Grand Amphithéâtre



Our understanding of cosmology traces back the origin of cosmic structures to quantum fluctuations of the primordial density field. However, the quantum-mechanical origin of cosmic inhomogeneities remains elusive to our observations. Environmental-induced decoherence is usually invoked as an inevitable obstruction to the detection of genuine quantum correlations in cosmology. Indeed, extra degrees of freedom are rather ubiquitous in inflationary models but their impact on the quantum information properties of primordial cosmic inhomogeneities has rarely been explored. I will present the cosmological open quantum system programme. It aims at modelling the impact of environmental degrees of freedom both on the usual cosmological observables (typically power spectrum and higher-order statistics) and on the quantum information properties of cosmic inhomogeneities. This programme will be illustrated considering a couple of examples. I will show that counterintuitively, quantum recoherence can proceed in cosmology highlighting that a quantitative assessment of the decoherence channels is becoming of increasing importance. 

Zoom link: https://univ-grenoble-alpes-fr.zoom.us/j/99695202196?pwd=bGVkL29Pb2JqeExqR2pPYzdHSk5pUT09