Average expansion rate and light propagation in a cosmological Tardis spacetime

Understand

We construct the first exact statistically homogeneous and isotropic cosmological solution in which inhomogeneity has a significant effect on the expansion rate.

• The universe is modelled as a Swiss Cheese, with dust FRW background and inhomogeneous holes.
• We show that if the holes are described by the quasispherical Szekeres solution, their average expansion rate is close to the background under certain rather general conditions.
• We specialise to spherically symmetric holes and violate one of these conditions.