Fundamental studies on quantum neural devices

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The follows are the key points of results of the research project "07650393 : Fundamental studies on quantum neral devices" supported by the Grant-in-Aid for Scientific Research (C), fiscal year 1995-1996. This project is to clues us to the final goal "realization of quantum neural devices" and will be followed by next-stage projects.1. Theoretical establishment of fundamentals for designing the devices and quantitative analyzesTheoretical analysis and simulations have been carried out to investigate the relation between the energy of the information carrier and the learning process in coherent optical neural networks using lightwave as the information carrier. The coherent neural networ can use the carrier-frequency space as a new degree of parallelism of neural information processing. However, it has been found that there is a sort of limitation in its initial state before learning for a meaningful generalization in the frequency domain. In the theory of backpropagation learning, we … More found periodic error-minimal valleys in the neural-connection delay space and the carrier frequency space, which are observed also in simulations. A learning process over the fold of such valley and mountain range cannot be performed in most cases. Therefore the network initial state have to be within a certain range of parameters (especially in the delay domain) for a smooth generalization. However, it has also been found that the limitation is very loose for the coherent networks and, hence, it is not a significant problem to realize a future quantum neural devices.2. Verification of basic dynamics by experiments using macroscopic electronic circuitsThe verification of the basic dynamics of the coherent neural networks for a future quantum neural devices are also in progress by using macroscopic high-frequency electronic circuits in the microwave and millimeterwave domain. A prototype of phase-sensitive coherent radar is constructed by which two-dimensional complex-valued data of rader objects are obtained. The raw data are process in a complex-valued neural network, which contains the key technology of the coherent networks and the quantum neural devices, in parallel only apparently by software on a von Neumann-type computer in the present preliminary experiment. In this experiment, it is found that the phase information on the objects is significantly effective for cognition or reconstruction of the object image. This result suggests that the coherent neural networks will give rise to a novel neural devices utilizing the coherent aspects of the information carrier (photons, electrons, ets.), i. e., the quantum neural devices. Less