Prof.
David L.
Wiltshire
School of Physical & Chemical Sciences, University of Canterbury, New Zealand.
The timescape cosmology returns to first principles, with quasilocal gravitational energy replacing dark energy, to explain apparent cosmic acceleration. As inhomogeneities grow, they back react on average cosmic expansion, which differs from conventional FLRW models. Crucially, dynamical spatial curvature arises as time-varying gradients of the kinetic spatial curvature, and depends directly on the void volume fraction. The first investigation of void statistics in cosmological simulations in full general relativity, without Λ, now supports this.
The timescape expansion history is close to ΛCDM, but with differences at a precision which we are now finally probing. Whereas ΛCDM is increasingly challenged -independent observational tests now favour timescape - some with strong Bayesian evidence. I will survey these results, open questions, current limitations, and possible future tests.
This is a hybrid event:
Room D, the Institute of Physics PAS, Al. Lotników 32/46
Online: Zoom Link, (Passcode: 134595, Meeting ID: 823 8038 0442)
