Testing Gravity Using the Growth of Large Scale Structure in the Universe
Dark energy and modified gravity models can produce similar expansion histories for the Universe, which can be derived from the Hubble parameter measured, for example, using Type Ia SN. The expansion history of the Universe in dark energy and modified gravity cosmologies can be described using an effective equation of state. If two models have the same equation of state, as a consequence, it is not possible to distinguish between them using measurements of the expansion history alone. However, cosmic structures are expected to collapse under gravity at different rates in the dark energy and modified gravity cosmologies.