Cosmological Gravity

A key assumption, at the heart of cosmological analysis, is that
gravity is accurately described by Einstein’s General Theory of
Relativity. While Einstein’s theory of gravity has stood the test of
time, as yet, the only precise tests of General Relativity are on much
smaller scales (of order 1 Astronomical Unit). Assuming they are
correct on cosmological scales involves an extrapolation of around 15
orders of magnitude.

At Oxford we are working on tests and constraints which could probe
the nature of gravity on the largest observable scales. In doing so
it should be possible to determine whether General Relativity or some
extension of it, is truly an accurate description of gravity in a
cosmological setting.

We are working on a three main topics to understand cosmological
gravity:
- we are building a formal framework that can unify gravitational
theories with a goal of coming up with a systematic classification;
- we are developing accurate tools for calculating observational
predictions on linear and non-linear scales;
- we are devising specific analysis methods and tools for current and
future cosmological observations.