Abstract
The conformal vacuum definition for non-inertial observers following the trajectories of the 9 conformal Killing vectors in Minkowski space-time is analyzed with the method of Hamiltonian diagonalization. The notion of physical fluid of reference is used to characterize the trajectories and to deduce the diagonalization condition. The existence of some privileged hypersurfaces on which a good vacuum definition can be made is suggested to be the first step towards a general theory of non-trivial vacua.
