Decaying Gravity
/ Authors
/ Abstract
We consider the possibility of energy being exchanged between the scalar and matter fields in scalar-tensor theories of gravity. Such an exchange provides a new mechanism which can drive variations in the gravitational ‘constant’ G . We find exact solutions for the evolution of spatially flat Friedman-Robertson-Walker cosmologies in this scenario and discuss their behaviour at both early and late times. We also consider the physical consequences and observational constraints on these models.