Quantum interference, complementarity and entanglement

Christian Ferrari, Bernd Braunecker

We present a didactical approach to the which-way experiment and the counterintuitive effect of the quantum erasure for one-particle quantum interferences. The fundamental concept of entanglement plays a central role and highlights the complementarity between quantum interference and knowledge of which path is followed by the particle.

J. M. Raimond

Gerold Wallner

Quantum information technology is one of the fastest growing sectors within information technology. By misleading interpretations of Bohr's definition of complementarity, the foundation of nonlocal correlations of entanglement is concealed and therefore, such nonlocal effects can apparently not be utilized directly in information technology. As the first step to identify the utilizable nonlocal property of entanglement, this paper adjusts the notion of complementarity of first-order and second-order interference. Especially, the nonlocal consequence of the "principle of least action" for entangled systems is shown by the foundation of second-order interference, the shared phase solutions space. Based on the concept of Feynman's path integral, the validity of the theory is demonstrated by applying the theory to well-known experiments, revealing this underlying nonlocal principle. In the next steps of publication, to highlight the relevance of this nonlocal principle for quantum computing and quantum information technology, the "self-consistency principle" of such nonlocal quantum causal correlations will be shown and verified by an experiment.

Arkady Plotnitsky

Christian Ferrari, Bernd Braunecker

We present a didactical approach to the which-way experiment and the counterintuitive effect of the quantum erasure for one-particle quantum interferences. The fundamental concept of entanglement plays a central role and highlights the complementarity between quantum interference and knowledge of which path is followed by the particle. © 2010 American Association of Physics Teachers. �DOI: 10.1119/1.3369921� I.