Quantum non-locality in two-photon experiments at Berkeley

The authors review some of the experiments performed over the past few years on two-photon interference. These include a test of Bell's inequalities, a study of the complementarity principle, an application of EPR correlations for dispersion-free time measurements, and an experiment to demonstrate the superluminal nature of the tunnelling process. The non-local character of the quantum world is brought out clearly by these experiments. As the authors explain, however, quantum non-locality is not inconsistent with Einstein causality.