Speaker
Description
"Quantum cosmology faces the problem of time: the Universe has no
background time, only interacting dynamical degrees of freedom within
it. The relational view is to use one degree of freedom (which can be
matter or geometry) as a clock for the others. In this talk we discuss a
cosmological model of a flat FLRW universe filled with a massless scalar
field and a perfect fluid. We study three quantum theories based on
three different choices of (relational) clock and show that, if we
require the dynamics to be unitary, all three make drastically different
predictions regarding resolution of the classical (Big Bang) singularity
or a possible quantum recollapse at large volume. The talk is based on
[arXiv:2005.05357] and a second paper to appear on arXiv in May 2021. We
plan to give two talks: one covering the foundations and general
properties of the model, and one showing detailed results and physical
interpretation. (We will merge these talks into one if the organisers
decide to accept only one talk.)"
