Quantum Mechanics in Non'Inertial Frames with a Multi'Temporal   Quantization Scheme: I) Relativistic Particles
  We introduce a family of relativistic non-rigid non-inertial frames as a gauge fixing of the description of N positive energy particles in the framework of parametrized Minkowski theories. Then we define a multi-temporal quantization scheme in which the particles are quantized, but not the gauge variables describing the non-inertial frames: {\it they are considered as c-number generalized times}. We study the coupled Schroedinger-like equations produced by the first class constraints and we show that there is {\it a physical scalar product independent both from time and generalized times and a unitary evolution}. Since a path in the space of the generalized times defines a non-rigid non-inertial frame, we can find the associated self-adjoint effective Hamiltonian $\hat{H}_{ni}$ for the non-inertial evolution: it differs from the inertial energy operator for the presence of inertial potentials and turns out to be {\it frame-dependent} like the energy density in general relativity. After a separation of the relativistic center of mass from the relative variables by means of a recently developed relativistic kinematics, inside $\hat{H}_{ni}$ we can identify the self-adjoint relative energy operator (the invariant mass) ${\hat{\cal M}}$ corresponding to the inertial energy and producing the same levels for the spectra of atoms as in inertial frames. Instead the (in general time-dependent) effective Hamiltonian is responsible for the interferometric effects signalling the non-inertiality of the frame but is not interpretable as an energy like in the case of time-dependent c-number external electro-magnetic fields. 
David Alba (Firenze University) and Luca Lusanna (INFN, Firenze)