3 research outputs found
Two Theorems on Flat Space-Time Gravitational Theories
The first theorem states that all flat space-time gravitational theories must
have a Lagrangian with a first term that is an homogeneous (degree-I) function
of the 4-velocity , plus a functional of . The second
theorem states that all gravitational theories that satisfy the strong
equivalence principle have a Lagrangian with a first term
plus an irrelevant term. In both cases the theories must issue from a unique
variational principle. Therefore, under this condition it is impossible to find
a flat space-time theory that satisfies the strong equivalence principle.Comment: 11 page