Minkowski space from quantum mechanics

Penrose's Spin Geometry Theorem is extended further, from $SU(2)$ and $E(3)$ (Euclidean) to $E(1,3)$ (Poincar\'e) invariant elementary quantum mechanical systems. The Lorentzian spatial distance between any two non-parallel timelike straight lines of Minkowski space, considered to be the centre-of-mass world lines of $E(1,3)$-invariant elementary classical mechanical systems with positive rest mass, is expressed in terms of \emph{$E(1,3)$-invariant basic observables}, viz. the 4-momentum and the angular momentum of the systems. An analogous expression for \emph{$E(1,3)$-invariant elementary quantum mechanical systems} in terms of the \emph{basic quantum observables} in an abstract, algebraic formulation of quantum mechanics is given, and it is shown that, in the classical limit, it reproduces the Lorentzian spatial distance between the timelike straight lines of Minkowski space with asymptotically vanishing uncertainty. Thus, the \emph{metric structure} of Minkowski space can be recovered from quantum mechanics in the classical limit using only the observables of abstract quantum mechanical systems.