Problems in Field Theoretical Approach to Gravitation

We consider gravitational self interaction in the lowest approximation and assume that graviton interacts with gravitational energy-momentum tensor in the same way as it interacts with particles. We show that, using gravitational vertex with a preferred gravitational energy-momentum tensor, it is possible to obtain a metric necessary for explaining perihelion precession. The preferred gravitational energy-momentum tensor gives positive gravitational energy density of Newtonian center. We show also that, employing " improvement " technique, any gravitational energy-momentum tensor can be made suitable for using in gravitational wave equation for obtaining metric which explains perihelion precession. Yet the " improvement " leads to negative gravitational energy density of the Newtonian center.