Abstract: A method for quantum classification and operation control includes radiating a vacuum chamber having an ensemble of neutral atoms with laser so as to trap atoms and form a quantum register. The method further includes the step of configuring a laser controlling function with M unitary operations based on a cost function for classification problems and a training dataset about a monitored target, radiating the ensemble of atoms accordingly, reading the quantum register, and setting a quantum classifier if the cost function with the values of the quantum register meet a condition, keep changing the laser controlling function and radiating the ensemble of atoms otherwise until a convergence condition is met, at which point the quantum classifier is set.

Abstract: The invention describes a memory device which combines a switchable resistive element and a superconductor element electrically in parallel. The switchable resistive element comprises an active material, which is switchable between first and second values of electrical resistivity ?1 and ?2 at the same temperature, wherein ?1 is different to ?2. The superconductor element is operable so that at least part of the superconductor element is switchable from a superconducting state to a non-superconducting state. When the superconductor element is switched from the superconducting state to the non-superconducting state, a current injection is provided through the switchable resistive element capable of switching the switchable resistive element between said first and second values of electrical resistivity.

Abstract: The present disclosure relates to a reciprocal quantum logic (RQL) inverter including an inverter bias tap, a pulse generating Josephson junction (JJ), and a superconducting quantum interference device (SQUID) based structure, which includes a SQUID JJ and is connected between the inverter bias tap and the pulse generating JJ. The SQUID based structure is configured to receive an inverter bias signal from the inverter bias tap and receive a data input from a previous circuit stage. When the data input is at logic state “0,” the pulse generating JJ can be triggered so as to provide an output signal with logic state “1.” When the data input is at logic state “1,” the first SQUID JJ can be triggered thereby preventing the pulse generating JJ from be triggered, such that the output signal is provided at logic state “0.

Abstract: A superconducting memory cell includes a magnetic Josephson junction (MJJ) with a ferromagnetic material, having at least two switchable states of magnetization. The binary state of the MJJ manifests itself as a pulse appearing, or not appearing, on the output. A superconducting memory includes an array of memory cells. Each memory cell includes a comparator with at least one MJJ. Selected X and Y-directional write lines in their combination are capable of switching the magnetization of the MJJ. A superconducting device includes a first and a second junction in a stacked configuration. The first junction has an insulating layer barrier, and the second junction has an insulating layer sandwiched in-between two ferromagnetic layers as barrier. An electrical signal inputted across the first junction is amplified across the second junction.

Abstract: A superconducting integrated circuit may include a magnetic flux transformer having an inner inductive coupling element and an outer inductive coupling element that surrounds the inner inductive coupling element along at least a portion of a length thereof. The magnetic flux transformer may have a coaxial-like geometry such that a mutual inductance between the first inductive coupling element and the second inductive coupling element is sub-linearly proportional to a distance that separates the first inner inductive coupling element from the first outer inductive coupling element. At least one of the first inductive coupling element and the second inductive coupling element may be coupled to a superconducting programmable device, such as a superconducting qubit.

Abstract: A method of operating a quantum system comprising computational elements, including an insulated ring of superconductive material, and semi-closed rings used as an interface between the computational elements and the external world, is disclosed. In one aspect, the method comprises providing an electrical signal, e.g. a current, in an input ring magnetically coupled to a computational element, which generates a magnetic field in the computational element and sensing the change in the current and/or voltage of an output element magnetically coupled to the computational element. The electrical input signal can be an AC signal or a DC signal. The computational element is electromagnetically coupled with other adjacent computational elements and/or with the interface elements. The corresponding magnetic flux between the computational elements and/or the interface elements acts as an information carrier. Ferromagnetic cores are used to improve the magnetic coupling between adjacent elements.

Abstract: A method includes providing a superconducting material having pinning sites that can pin magnetic vortices within the superconducting material. The method also includes pinning one or more magnetic vortices at one or more of the pinning sites. An information storage apparatus includes a superconducting material, doped particles within the superconducting material that can pin dipole magnetic vortices, a magnetic tip that generates pinned magnetic vortices and a magnetic detector that detects pinned magnetic vortices.

Abstract: A three-dimensional element is fabricated from a high-temperature superconductor. The method and apparatus can fabricate, for example, a single-electron tunnel device or an intrinsic Josephson device which utilize the layer structure peculiar to the high-temperature superconductor, with machining from the side surface of a monocrystal or thin film. In the focused-ion beam etching, a substrate holder which is rotatable about 360°, is rotated, at the minimum, through an angle of about 90°, and the thin film or monocrystal on the substrate is etched from the side surface thereof so as to fabricate the element. After the thin film or monocrystal is machined from above by means of an focused-ion beam to thereby form a bridge having a junction length, the sample is rotated by about 90° (270°). Subsequently, a multi-layer current path layer is formed through side-surface machining. The junction length is accurately controlled through measurement of the current path length from an image display.

Abstract: A multi-state Josephson memory in a superconductor integrated circuit includes a plurality of superconductive quantum interference device (SQUID) memory cells 2 each having a SQUID 4 characterized by a SQUID loop inductance L and a junction critical current I.sub.c, which determine the number of memory states that can be stored in the SQUID 4. A gate current I.sub.g is transmitted to the superconductive inductors 6 and 8 of the SQUID 4 to perform a read operation by crossing a designated number of current threshold boundaries corresponding to the memory state stored in the SQUID, so that the Josephson junction 12 of the SQUID 4 generates a number of pulses corresponding to the memory state. A control current I.sub.con writes data to the SQUID 4 through a control current input 16, and is preferably magnetically coupled to the SQUID 4 through superconductive inductor pairs 18, 6 and 20, 8. In a preferred embodiment, a plurality of SQUID memory cells 70a, 70b, . . .

Abstract: A three-terminal device constructed from a Josephson junction with one or more asymmetric control lines is disclosed. The device is constructed with high temperature superconducting materials. The junction can be a bicrystal, SNS (Superconducting-Normal-Superconducting) or any other type of high temperature superconductor junction. The control line is either a conducting or superconducting material which is electrically isolated from the junction but inductively coupled into the junction. A portion of the control line is approximately directly above the junction and has current which at least partially flows parallel or nonparallel to current flowing across the junction. The control line current alters the magnetic field within the junction which changes the critical current of the junction. The junction is in a superconducting or resistive state depending on whether the bias current of the junction is greater than or less than the control current.

Abstract: A superconducting fault-tolerant programmable read-only memory (SFT-PROM) cell stores information in the phases of superconducting wires in a Josephson array. The information is addressable and retrievable in a fault-tolerant manner due to the non local nature of the information stored. The coding and decoding process is content-addressable and parallel due to the multitude of interconnections, resulting in picosecond data access time. The SFT-PROM cell comprises superposed WRITE/READ arrays and a reset circuit that ensures multiple non-destructive read-out of data.

Abstract: A memory element for multiple bit storage uses a plurality of Josephson junction devices coupled in parallel between a ground plane and a superconductive line. A gate current is directly coupled to the superconductive line at a midpoint, and a control current is magnetically coupled to the superconductive line along its length. The current trajectory of the gate and control currents from an initial value to a quiescent point in the threshold curve traces determines the states of the modes. All the modes have a stable operating point at the quiescent point. The control current in the absence of the gate current is used to maintain the memory element at the quiescent point, and the gate current is used to momentarily transition none, one or more of the Josephson junction devices to a voltage state to determine the states of the modes at the quiescent point via appropriate Josephson sensors.

Abstract: A process for fabricating the Josephson junction includes the steps of preparing a substrate, forming a first superconducting layer, forming a second superconducting layer transversely on the first layer with an insulating layer interposed therebetween wherein the insulating layer is an oxide or nitride of the superconducting material, and injecting ion beams into the insulating layer so as to form low oxygen- or nitrogen-concentrated area linking the first and second layers.

Abstract: A superconducting device may include a superconducting weak link equipped with plural superconducting devices that are used as input-output terminals formed on the same plane and at least one current source for applying current to at least one of these superconducting electrodes. A superconducting device suitable for high integration can be realized as it enables structuring of a superconducting weak link 1 equipped with plural superconducting electrodes 101, 102, 103 and 104 that can be used as input-output terminals and changing symmetry of superconducting electrode arrangement through the form of a normal conductor 201 which is forming a superconducting weak link. In addition, when this superconducting device is used as a quasi-particle injection type device, a superconducting device with plural superconducting electrodes that can be used for a gate electrode, drain electrode or control electrode can be realized. Further, a superconducting device equipped with new functions (e.g.

Abstract: A SQUID comprises a substrate, a washer of an oxide superconductor thin film formed on a principal surface of the substrate, a hole shaped a similar figure to the washer at the center of the washer, a slit formed between one side of the washer and the hole, and a Josephson junction which connects portions of the washer at the both sides of the slit across the slit. In the SQUID, the ratio of similarity of the washer to the hole ranges 100 to 2500.

Abstract: A process for producing a Josephson device is disclosed, wherein a Josephson junction is formed over a recess step by oblique deposition and a protective layer of conducting material or semiconducting material is formed on the Josephson junction. The actual thickness of the Josephson junction is controlled to be smaller due to the proximity effect.

Abstract: A new type of superconducting memory is described. The composition of superconducting ceramic material used in the memory has been altered in order to expedite the formation of non-superconducting regions formed of grain boundaries. Non-superconducting regions may also be formed of lattice defects. Magnetic flux is trapped within the non-superconducting regions (grain boundaries or lattice defects). Information can be stored in terms of whether or not magnetic flux is trapped.

Abstract: A process for formulating non-hysteretic and hysteretic Josephson junctions using HTS materials which results in junctions having the ability to operate at high temperatures while maintaining high uniformity and quality. The non-hysteretic Josephson junction is formed by step-etching a LaAlO.sub.3 crystal substrate and then depositing a thin film of TlCaBaCuO on the substrate, covering the step, and forming a grain boundary at the step and a subsequent Josephson junction. Once the non-hysteretic junction is formed the next step to form the hysteretic Josephson junction is to add capacitance to the system. In the current embodiment, this is accomplished by adding a thin dielectric layer, LaA1O.sub.3, followed by a cap layer of a normal metal where the cap layer is formed by first depositing a thin layer of titanium (Ti) followed by a layer of gold (Au). The dielectric layer and the normal metal cap are patterned to the desired geometry.

Abstract: A superconducting tunnel element, having a plurality of super conductors separated by barriers, the superconductors each comprising two physically separate but electrically connected superconducting layers and one insulated control layer. As a result, summation of the detection capacity or of the transmitting intensity becomes possible. Also, the simultaneous detection or transmission is permitted on arbitrary different frequencies or a summation of the signal intensity is possible in the case of SQUID-systems.

Abstract: A quantum memory device in which a memory operation is enabled even if the structure of a Josephson device is reduced in size. Each memory cell of the quantum memory device includes a superconducting quantum interference device having two Josephson junctions, a write word line for supplying a current to the superconducting quantum interference device, a write data line and a magnetic field detection line magnetically coupled with the superconducting quantum interference device, a three-terminal switching device for turning a signal of the magnetic field detection line on and off to transfer the signal to a read data line, and a read word line connected to a gate of the three-terminal switching device. The junction area of the Josephson junction is made small to oscillate a magnetic flux so that information is stored in accordance with the phase of oscillation of the magnetic flux.

Abstract: This device or junction is essentially constituted by a substrate made from an electrically insulating material (2), a vertical wall (4) formed on the substrate and extending in a given direction (x), said wall being made from said insulating material, a superconducting material ribbon (8) in two separate parts (10, 12) located on either side of the wall and bearing on the latter, the ribbon being oriented in a direction perpendicular to the said direction, and two interconnection contacts (14, 16) respectively placed on the two portions of the ribbon.

Abstract: In a Josephson device which can be employed as a sensor including superconductor for measuring an extremely weak magnetic field, a Josephson junction consisting of superconducting material is formed, and a covering layer consisting of ordinary conducting metal or semiconductor is formed on the Josephson junction. This enables the Josephson junction to be isolated from the oxidized atmosphere. Further, the covering layer is not to present any deterioration such as cracks even upon being subjected to a thermal hysteresis from very low temperature to ordinary temperature.

Abstract: A method of manufacturing a DC superconducting quantum interference device comprises forming an insulating film over a portion of a resistance film. A lower electrode superconducting film is formed over the resistance film and the insulating film. A barrier layer is formed on a portion of the lower electrode superconducting film. An upper electrode is formed sandwiching the barrier layer between the lower electrode superconducting film and the upper electrode, so as to form a Josephson junction. To reduce the number of manufacturing steps, the lower electrode superconducting film is photolithographically patterned and/or etched to simultaneously form an input coil, a feedback coil and the Josephson junction. In another embodiment, after forming the upper electrode, an insulating film is formed over at least a portion of the lower electrode superconducting film. A superconducting film is formed over the insulating film in contact with the upper electrode.

Abstract: A high current amplifier, three terminal device, comprising a Josephson tunnel junction and a Schottky diode is configured so that the Josephson junction and Schottky diode share a common base electrode which is made very thin. Electrons which cross the Schottky barrier are supplied to the Josephson junction to obtain the amplified output current.

Abstract: A Josephson junction and a method for its fabrication in which a laminated junction layer is formed in situ on the side edge of a base electrode contact. The laminated junction layer forms the Josephson junction of the present invention and includes an insulating or barrier layer sandwiched between a superconducting base electrode and a superconducting counter electrode. The Josephson junction is formed on the side edge of the base electrode contact to allow very small junction areas to be fabricated using conventional optical lithographic techniques, such as photolithography. The laminated junction layer is formed in situ, with the three layers of the laminated junction layer being formed successively without removing the device from the controlled atmosphere of the deposition system, to prevent contamination of the junction region.

Abstract: One or more superconducting memory cells capable of storing binary values as the presence or absence of a persisting loop current in their superconducting memory loops are connected in series by a circuit current line. This arrangement is provided with a set gate which switches to the voltage state and outputs circuit current from its output terminal to one end of the circuit current line when write command current is supplied to its control terminal and is further provided with a sense gate whose control terminal is series coupled though a capacitance element with the same one end of the circuit current line and whose ground side terminal is connected with the other end of the circuit control line thereby forming through the sense gate a read-out loop for receiving as differential current persisting loop current selectively discharged from the memory loop. The differential current causes the sense gate to switch itself to the voltage state and output a sense current.

Abstract: Disclosed is a transistor or diode type Josephson effect device, at least two electrodes of which are made of superconductive material. If the Josephson effect is to be exerted in a semiconductor layer between the access electrodes, the distance between them should be smaller than the length of coherence, namely 10 to 1000 angstroms. According to the disclosure, the control channel between access electrodes is replaced by two channels perpendicular to the semiconductor layer, located between the two access electrodes and a layer of superconductive material placed between the substrate and the semiconductor layer. The disclosure can be applied to transistors, phototransistors and diodes with high switching speed.

Abstract: A field-effect transistor comprises, on a substrate, a layer of semiconductor material incorporating natural or artificial inclusions of superconducting material. The source, drain and gate electrodes are made on this layer. Applications: field-effect transistors with low gate control voltage. FIG. 3.

Abstract: A high T.sub.c oxide superconductive switching device [10] formed on a substantially planar substrate [18] includes a base electrode [12] comprised of a layer or film of anisotropic superconducting material. The layer has a first crystalline axis [c] along which a magnitude of an energy gap of the material is less than an energy gap of the material along other crystalline axes. The superconductive switching device further includes at least one injector electrode [14] forming a planar [16] or an edge tunneling junction with the base electrode for injecting, under the influence of a bias potential eV, quasiparticles into the base electrode. The first crystalline axis is aligned in a predetermined manner with the tunneling junction for optimizing a quasiparticle injection efficiency of the tunneling junction.

Abstract: A thin film dc SQUID and its driving electronic circuitry configured with very high symmetry. The SQUID loop is formed with four holes at the respective ends of crossed slits. Each of these holes forms a single turn secondary for symmetrically arranged pairs of modulation coils and signal coils. The geometrical placement of the modulation coil transformers with respect to the signal coil transformers results in a device which nominally has no mutual inductance between the two groups of coils when the SQUID is biased for normal operation. The external driving circuit is configured to preserve the highly balanced nature of the chip and forces equal magnitudes of current to flow in all four of the bias leads.

Abstract: This invention relates to a magnetic memory including a first superconductor wire, a second superconductor wire disposed in such a manner as to cross the first superconductor wire substantially orthogonally, a first magnetic film disposed at the point of intersection between the first and second superconductor wires and a second magnetic film interposed between the first magnetic film and the first or second superconductor films, wherein at least one of the uniaxial magnetic anisotropy within the plane of the films and coercive force of the first and second magnetic films is mutually different. Furthermore, a superconductor film containing a large number of microscopic Josephson junctions is disposed between the first and second magnetic films or on the other side of the superconductor wire connected to the magnetic film, and a lead wire for applying a current is connected to the superconductor film.

Abstract: A noble unit cell structure in a magnetic memory is disclosed, in which a ferromagnetic film is sandwiched between first and second wires at a cross-over area, and third and fourth wires are provided so as to sandwich the first wire. The third wire is contacted with the first wire so as to form a ring portion surrounding the ferromagnetic film and the second wire. The fourth wire is isolated from the first wire. At least the first, second and third wires are made of superconductive material. The ferromagnetic film has a uniaxial anisotropy along the second wire and its magnetization direction can be reversed by applying pulse currents to the second and fourth wires in an information writing process. In a reading process, the magnetization direction of the ferromagnetic film can be recognized by detecting either one of a superconductive state or a normal conductive state at the ring portion of the first and third wires.

Abstract: A process is disclosed of producing on a crystalline silicon substrate a barrier layer triad capable of protecting a rare earth alkaline earth copper oxide conductive coating from direct interaction with the substrate. A silica layer of at least 2000 .ANG. in thickness is deposited on the silicon substrate, and followed by deposition on the silica layer of a Group 4 heavy metal to form a layer having a thickness in the range of from 1500 to 3000 .ANG.. Heating the layers in the absence of a reactive atmosphere to permit oxygen migration from the silica layer forms a barrier layer triad consisting of a silica first triad layer located adjacent the silicon substrate, a heavy Group 4 metal oxide third triad layer remote from the silicon substrate, and a Group 4 heavy metal silicide second triad layer interposed between the first and third triad layers.

Abstract: Superconducting material improves the operating efficiency and reduces the operating power demand for a disk drive suitable for interchanging data with a magnetic or optic medium. The arm containing the head is moved along a path by a balanced superconductor-to-magnetic-field interface such as for radial positioning relative to a circular medium and is maintained in constant spatial relation with respect to the medium by advantageous application of superconductive layers and magnetic field sources. The superconductor environment also permits efficient bearing support for the medium as well as accommodating superconductor motors for driving the medium, and the use of various circuit elements associated with the drive electronics.

Abstract: A method of producing a Josephson junction device consisting of thin films of superconducting materials such as niobium and niobium nitride that work at cryogenic temperatures, in which a base electrode layer, tunnel barrier layer and a counterelectrode layer constituting a Josephson junction are formed on a substrate. In order to form a desired electrode pattern on the counterelectrode layer, a resist pattern is used as a mask for dry etching, followed by a plasma ashing process for ablating part of the resist in order to form a terrace-shaped portion at the edges and corners of the counterelectrode pattern by reforming and shrinking the cross-sectional geometry of the resist. Then, a thin insulating film for covering the edged layers is deposited over the entire surface of substrate, followed by the removal of said resist pattern together with said insulating film deposited on said resist pattern in order to form a protecting layer around the counterelectrode pattern.

Abstract: A self-powered electronic component, particularly, a Josephson junction, is formed of a layer of a superconductor epitaxially grown on a substrate formed of a single crystal of silicon. In accordance with one embodiment of the invention, the expitaxial superconductor layer is separated into two parts by a groove defined by a thin growth region, forming the Josephson junction. On the epitaxial layer at the first side of the junction is deposited a thin layer of an insertion material forming the positive pole of the Josephson junction as well as the cathode of a solid state power generator. On the epitaxial layer and over the thin layer of insertion material is deposited a separator, or fast ion conductor, which assumes the weak link of the Josephson junction as well as separates the ion source from the electronic exchanger and assumes the fast ion transport.

Abstract: A method of making a Josephson Junction is disclosed which includes the steps of depositing a base electrode layer of a refractory superconducting material on a substrate, depositing a first passivation layer on the base electrode, depositing a barrier layer of refractory insulating semiconducting material on the passivation layer, depositing a second passivation layer on the barrier layer, and depositing a counter electrode on the second passivation layer. The layers are deposited at a substrate temperature of from about 50.degree. C. to about 700.degree. C. in an Ultra-High Vacuum sputtering system at a base pressure of less than or equal to 5.times.10.sup.-8 Torr. In the preferred embodiment a base electrode and counter electrode of NbN are separated by a barrier layer of hydrogenated silicon. When exposed to high post processing temperatures this structure maintains a chemically stable interface with the substrate.