The standard approach to modelling the late time acceleration of the Universe is to introduce a dark energy component and arrange its properties such that it dominates at late times and violates the strong energy condition. However, an alternative approach to describing the current epoch is to postulate that at cosmological distance scales, gravity deviates from its standard General Relativistic description. This can be achieved, for example, by introducing fields which mediate gravity in addition to the standard spin-2 graviton. The aim is to construct a gravitational model which allows for accelerated expansion in the absence of dark energy on large scales, yet approximately reproduces standard Newtonian and Einsteinian gravity on galactic and solar system scales.
Our group conduct research on a variety of modified gravity models, with focus on constraining deviations from General Relativity using both theoretical considerations and observational data sets.
Equation for action in F(R) gravity (Credit: Stephen