Nonlocality and polarization correlations of annihilation quanta

Abstract

The question of nonlocal effects in quantum theory is discussed in the light of the new polarization correlation measurements for positron annihilation quanta with polarimeter separations of up to 5 m recently reported by Wilson, Lowe and Butt. We show that these results imply that nonlocal quantum correlations persist at least to distances covered by this work and rule out the possibility of a spontaneous localization process which depends only on the coherence length of the annihilation radiation. © 1976 Società Italiana di Fisica.