SPACE seminar: Leila L. Graef - "The Back-Reaction Effect of Super-Hubble Cosmological Fluctuations in light of DESI"

Tuesday 24 Feb 2026, 12:00 → 13:00 Europe/Rome

Aula 4 (San Marcellino)

Speaker: Prof. Leila L. Graef (Instituto de Física, Universidade Federal Fluminense, Brazil)

Abstract: Previous studies suggested that the back-reaction of super-Hubble cosmological fluctuations could lead to a dynamical relaxation of the cosmological constant. Moreover, this mechanism appears to be self-regulatory, potentially leading to an oscillatory behavior in the effective dark energy. In this seminar, after reviewing the main advances in the topic, I will present our recent work where we perform a preliminary comparison of the background dynamics of this model with the recent radial BAO data from DESI DR2.

References:

1. M.A.C. Alvarez, L.L. Graef, R. Brandenberger, Back-Reaction of Super-Hubble Fluctuations, Late Time Tracking, and Recent Observational Results, Symmetry 17, no.9, 1507 (2025), arXiv:2502.17395 [astro-ph.CO] 
2. R. Brandenberger, L.L. Graef, G. Marozzi, G.P. Vacca, Backreaction of super-Hubble cosmological perturbations beyond perturbation theory, Phys. Rev. D 98, 103523 (2018), arXiv:1807.07494 [hep-th]

 

Zoom link: click here