General Quantum Interference Principle and Duality Computer

In this article, we propose a general principle of quantum interference for\nquantum system, and based on this we propose a new type of computing machine,\nthe duality computer, that may outperform in principle both classical computer\nand the quantum computer.\n According to the general principle of quantum interference, the very essence\nof quantum interference is the interference of the sub-waves of the quantum\nsystem itself. A quantum system considered here can be any quantum system: a\nsingle microscopic particle, a composite quantum system such as an atom or a\nmolecule, or a loose collection of a few quantum objects such as two\nindependent photons.\n In the duality computer, the wave of the duality computer is split into\nseveral sub-waves and they pass through different routes, where different\ncomputing gate operations are performed. These sub-waves are then re-combined\nto interfere to give the computational results. The quantum computer, however,\nhas only used the particle nature of quantum object. In a duality computer, it\nmay be possible to find a marked item from an unsorted database using only a\nsingle query, and all NP-complete problems may have polynomial algorithms. Two\nproof-of-the-principle designs of the duality computer are presented: the giant\nmolecule scheme and the nonlinear quantum optics scheme. We also proposed\nthought experiment to check the related fundamental issues, the measurement\nefficiency of a partial wave function\n