Five-dimensional PPN formalism and experimental test of Kaluza-Klein theory

Understand

The parametrized post Newtonian formalism for 5-dimensional metric theories with a compact extra dimension is developed.

• The relation of the 5-dimensional and 4-dimensional formulations is then analyzed, in order to compare the higher dimensional theories of gravity with experiments.
• It turns out that the value of post Newtonian parameter $\gamma$ in the reduced 5-dimensional Kaluza-Klein theory is two times smaller than that in 4-dimensional general relativity.
• The departure is due to the existence of an extra dimension in the Kaluza-Klein theory.