Abstract: To obtain good approximate solutions of a combinatorial optimization problem such as traveling salesman problem and to enable its processing apparatus in form of massively parallel exclusive devices, an information carrier corresponding to the distribution of a plurality of points given on an n-dimensional space (n is an integer not smaller than 2), and time development and time reversal of the information carrier are used to process the information. The information carrier may be the density of particles or optical intensity corresponding to the distribution of the given points, and a diffusion process of the particles or a defocusing process is used as changes with time. The traveling salesman problem is solved by using this method.

Abstract: A quantum box structure and a carrier conductivity modulating quantum device are disclosed. The quantum box structure comprises a quantum boxes array including a plurality of quantum boxes arranged adjacent to each other on a common plane. Each quantum box is asymmetric in a direction orthogonal to the plane in one of composition of materials constituting the quantum box and geometry of the quantum box. The carrier conductivity modulating quantum device comprises a plurality of regions including quantum boxes arrays including a plurality of quantum boxes arranged on a common plane. Each regions exhibits at least one of a metal phase and an insulator phase. Each quantum box is asymmetric in a direction orthogonal to the plane at least in one of composition of materials constituting the quantum box and geometry of the quantum box.

Abstract: A quantum box structure and a carrier conductivity modulating quantum device are disclosed. The quantum box structure comprises a quantum boxes array including a plurality of quantum boxes arranged adjacent to each other on a common plane. Each quantum box is asymmetric in a direction orthogonal to the plane in one of composition of materials constituting the quantum box and geometry of the quantum box. The carrier conductivity modulating quantum device comprises a plurality of regions including quantum boxes arrays including a plurality of quantum boxes arranged on a common plane. Each regions exhibits at least one of a metal phase and an insulator phase. Each quantum box is asymmetric in a direction orthogonal to the plane at least in one of composition of materials constituting the quantum box and geometry of the quantum box.

Abstract: A charge transfer device comprises a quantum wire and a one-dimensional quantum dots array extending helically, for example, and including quantum dots which are aligned in close relation to couple with each other and to surround the quantum wire. By applying an external field within a plane normal to the quantum wire and by rotating the direction of the application of the external field, charges are transferred along the quantum wire.

Abstract: A collective element of quantum boxes includes a plurality of the first quantum boxes (QD.sub.1) arranged within the first surface, between which conduction of electrons is allowed, a plurality of the second quantum boxes (QD.sub.2) arranged within the second surface corresponding to the plural first quantum boxes (QD.sub.1) between which conduction of electrons and holes is not substantially allowed, and a plurality of the third quantum boxes (QD.sub.3) arranged within the third surface corresponding to the plural second quantum boxes (QD.sub.2), between which conduction of holes is allowed.

Abstract: A quantum memory has memory cells, each of the memory cells includes three-stage quantum dots stacked in sequence. A memory cell array is constructed by two-dimensionally arranging the memory cells. The quantum dots are made of heterojunctions of compound semiconductors. Writing and reading to and from a memory cell are executed by bringing a needle electrode close to the memory cell to apply an external electric field while irradiating laser light to an area including the memory cell.

Abstract: A method of manufacturing a quantum device such as a coupled quantum boxes device are disclosed. The quantum device comprises: a semiconductor substrate; a plurality of box portions made of a first semiconductor; and a layer made of a second semiconductor provided on circumferences of the box portions, a plurality of quantum boxes being provided with the box portions and the layer of the second semiconductor. The manufacturing method comprises the steps of: making a plurality of box portions of a first semiconductor on a semiconductor substrate; and covering circumferences of the box portions with a layer of a second semiconductor, a plurality of quantum boxes being provided with the box portions and the layer of the second semiconductor.

Abstract: A field effect transistor has a quantum dot array in its channel region. The quantum dot array is composed of a plurality of quantum dots arranged adjacent to each other on a common plane. Each quantum dot may be made of heterojunction of compound semiconductors or junction of a semiconductor and an insulator. The field effect transistor has a differential negative resistance.

Abstract: A quantum box array comprising a plurality of quantum boxes is made by providing a plurality of box-shaped quantum well portions on a first barrier layer and a second barrier layer covering the quantum well portions. The quantum box array is designed so that interaction energy between electrons or holes is amply larger than transfer energy between the quantum boxes. A control electrode is provided on the second barrier layer to vary the number of electrons or holes in the quantum box array by changing the potential of the control electrode. In spite of using a relatively small number of electrons or holes, the quantum device can suppress fluctuation in density of electrons or holes, can have three or more states, and reduces the power consumption.

Abstract: A data processing system formed of a collective element of quantum boxes including an electrode and a plurality of quantum boxes which respectively have a barrier layer made of the first semiconductor on the electrode and a well layer made of a second semiconductor adjacent to the barrier layer. The first semiconductor has an electron affinity .PHI..sub.B and an energy gap E.sub.gB. The second semiconductor has an electron affinity .phi..sub.W and an energy gap E.sub.gW. The equations .phi..sub.W >.phi..sub.B and .phi..sub.W +E.sub.gW >.phi..sub.B +E.sub.gB are simultaneously satisfied.

Abstract: Disclosed is hererin a quantum phase interference transistor comprising: an emitter for emitting electron waves into a vacuum; a gate electrode for controlling the phase difference between a plurality of electron waves; and a collector for collecting the electron waves; characterized in that the gate electrode has the construction of a capacitor.

Abstract: In quantum effect devices using quantum dots, a novel quantum effect device which controls the probability of tunnel transition of electrons among quantum dots to obtain quantum effects such as band gap modulation. i-GaAs layers serving as the quantum dots are formed on an n-AlGaAs substrate and, further, n-AlGaAs layers are formed as electron supply layers on the i-GaAs layers. By this double heterojunction structure, channels are formed in the i-GaAs layers near the two junction surfaces sandwiching the layers. On the other hand, a potential barrier layer comprised of an i-AlGaAs layer with a small barrier height with respect to the quantum dots and an SiO.sub.2 layer with a large barrier height laminated together is formed between the quantum dots. The position of the lamination interface in the potential barrier layer is set to a height enabling the two layers to contact the quantum dots.

Abstract: A vacuum microelectronic transistor which can operate at a high speed and has a high mutual conductance. The vacuum microelectronic transistor comprises an emitter for emitting electrons therefrom, a collector for receiving electrons from the emitter, and a pair of gate electrodes for controlling arrival of electrons from the emitter to the collector. The emitter and collector are disposed in an encapsulated condition on a substrate such that electrons emitted from the emitter run straightforwardly in vacuum to the collector while the gate electrodes are located adjacent and across a route of such electrons from the emitter to the collector. Also, a process of manufacturing such vacuum microelectronic transistor is disclosed.

Abstract: Disclosed is a method which enabled the precise formation of a group of quantum dots. A device which functions on the principle of a transmission type electron microscope is used to produce a beam of electrons which are passed through a thin crystal membrane in order to produce an electron beam diffraction image. The energy distribution of the diffracted electron beam is used to produce masks, enable epitaxial growth and dry etching involved with the microscopic fabrication operations. For example, a thin GaAs membrane is used to form a diffracted electron beam image on a GaAs layer formed on a substrate. Carbon is then supplied and used to form carbon layers on the the locations where the beam energy is strongest. These carbon layers are used as a mask which allow selective etching of the GaAs layer.

Abstract: Disclosed is hererin a quantum phase interference transistor comprising: an emitter for emitting electron waves into a vacuum; a gate electrode for controlling the phase difference between a plurality of electron waves; and a collector for collecting the electron waves; characterized in that the gate electrode has the construction of a capacitor.