Fig. 5 (a) Minkowski diagram of Freedman-Clauser experiment showing lightlike world lines of advanced and retarded waves from emitter (solid) and absorbers (dashed) providing nonlocal enforcement of polarization correlations between absorption loci D1 and D2. (b) Four-vector sum of advanced and retarded waves connecting D1 to D2. (c) Four-vector sum of advanced and retarded waves connecting D2 to D1.