GRG18 5b

Earlier this afternoon there were 2 notable short talks by Steve Giddings in the Quantum Cosmology session. First, he reconsidered the original Hawking radiation calculation by asking to what extent higher quantum corrections actually matter, in the light of a resolution to the information paradox via the new concensus that macroscopic locality is abandonned. In this talk he discussed a breakdown of the original argument at time scales around M^3, and in the second talk (on a de Sitter background) he mentioned several independent analyses that point to a break down of perturbative QFT at time scales of the order of R.S where R is a deSitter radius and S its entropy. This is based on joint work with Marolf, based on the idea that non-locality must be considered, very fundamentally, in a relational setting, and in fact the talk began with a slide listing historical work on such approaches to gravity. He also made the point that strings could not address the kind of non-locality that seemed to be required.