Séminaire Doctoral / Seminar PhD |
« Looking for quantumness in the CMB » |
Amaury Micheli |
The anisotropies visible in the CMB map by Planck represent the density inhomogeneities in the early Universe. These inhomogeneities are the seeds of the large-scale structure that then form by gravitational collapse. Surprisingly enough the leading paradigm to explain the origin of these is that they derive from initial vacuum fluctuations at the beginning of inflation later stretched to cosmological distances by the expansion. This apparent tension between the quantum origin of the fluctuations and the scale of the inhomogeneities makes it natural to wonder to what extent the initial quantum character of the fluctuations is retained in the final distribution. First, I will try to take you from an intuitive idea of what we could call a quantum effect to a possible formalization of what is a genuine quantum prediction. This approach will be exemplified with two criteria : Bell inequalities and Quantum Discord. Then, I will briefly discuss how the quantum character of a state can be destroyed using the concept of decoherence.
Finally, going back to cosmology, the developed tools will be applied to the case of the cosmological perturbations with a critical look. |
vendredi 18 mars 2022 - 16:00 Salle du Conseil, Institut d'Astrophysique |
Page web du séminaire / Seminar's webpage |