# Feynman's attempt at QFT theory of graviton as spin-2 particle

Feynman has tried to describe gravitation in term of spin-2 quantum field theory. A quite detailed account is given of this attempt in his "Lectures on Gravitation". However, my grasp of QFT is not enough to see where the theory fails to be satisfactory. To this day, the interpretation of graviton as a spin-2 particle is still something very speculative, and I wanted to know why, at least from a theoretical point of view. Any reference to specific published papers is welcome.

Not with all theories the process of renormalization goes smoothly. In the standard model the renormalization can be always carried out by redefining already existing coupling constants, and no additional constants are needed: we say that the standard model is renormalizable, and it makes sense as a perturbative QFT. Sure, maybe it is inappropriate to use in strong coupling situations (like low energy QCD) due to its perturbative nature, but at least the theory is well defined. Note that the action of the standard model only contains a spin 0 boson (the Higgs field), spin $1/2$ fermions (leptons and quarks), and gauge spin 1 bosons (the vector mediators of the forces). No spin 2 particle is present.