EPR-BELL TESTS WITH UNSHARP OBSERVABLES AND RELATIVISTIC QUANTUM MEASUREMENT

摘要

The Einstein-Podolsky-Rosen argument will be revisited and its validity checked for the case of realistic, imperfect measurements described in terms of positive operator valued measures. It is shown how Bell's inequalities can be satisfied if the degree of unsharpness in the observables involved is sufficiently large. The EPR contradiction between the assumptions of (usharp) reality, locality and the validity of quantum mechanics is resolved by maintaining realism and quantum mechanics and weakening locality. The form of nonlocality allowed is that of objectification-af-a-distance. Problems associated with the quantum description of localised, spacelike separated measurements are briefly discussed.