Classical wave-optics analogy of quantum information processing

摘要

An analogous model system for quantum information processing is discussed,based on classical wave optics. The model system is applied to three examplesthat involve three qubits: ({\em i}) three-particle Greenberger-Horne-Zeilingerentanglement, ({\em ii}) quantum teleportation, and ({\em iii}) a simplequantum error correction network. It is found that the model system cansuccessfully simulate most features of entanglement, but fails to simulatequantum nonlocality. Investigations of how far the classical simulation can bepushed show that {\em quantum nonlocality} is the essential ingredient of aquantum computer, even more so than entanglement. The well known problem ofexponential resources required for a classical simulation of a quantumcomputer, is also linked to the nonlocal nature of entanglement, rather than tothe nonfactorizability of the state vector.