Agnostic Approaches to Gravity

Tue, May 03, 2016

The past decade has witnessed an explosion in the number of alternative gravity theories in the literature. Unfortunately, progress in testing these theories against cosmological data and eliminating them has been much slower. This has left us uncertain which direction in the ‘theory landscape’ is most worthy of our attention. I’ll present a new, theoretically consistent parameterisation for testing gravity in a completely model-independent way. Such agnostic frameworks offer protection from the shifting fashions of particular modified gravity theories. I’ll show the current constraints on this parameterisation, and indicate the role of future surveys in improvements. I’ll also show a visualisation of how cosmological constraints fit in with the `big picture’ of gravity, which extends to the astrophysical, laboratory and strong-field regimes.