  Spacetime is modelled as a homogeneous manifold given by the classes of
unitary $\U(2)$ operations in the general complex operations $\GL(\C^2)$. The
residual representations of this noncompact symmetric space of rank two are
characterized by two continuous real invariants, one invariant interpreted as a
particle mass for a positive unitary subgroup and the second one for an
indefinite unitary subgroup related to nonparticle interpretable interaction
ranges. Fields represent nonlinear spacetime $\GL(\C^2)/\U(2)$ by their
quantization and include necessarily nonparticle contributions in the timelike
part of their flat space Feynman propagator.
