The Einstein equivalence principle in the electromagnetic sector can be violated modifications of gravity theory generated by a multiplicative coupling scalar field to Lagrangian. In such theories, deviations standard result for cosmic distance duality relation, and variation fine structure constant are expected unequivocally intertwined. this paper, we search these possible cosmological signat...

Improved terrestrial experiment to test the equivalence principle for rotating extended bodies is presented, and a new upper limit for the violation of the equivalence principle is obtained at the level of 1.6×10, which is limited by the friction of the rotating gyroscope. It means the spin-gravity interaction between the extended bodies has not been observed at this level. Typeset using REVTEX