Abstract: Techniques regarding a quantum entangling gate between multi-mode superconducting qubits are provided. For example, one or more embodiments described herein can comprise an apparatus, which can comprise a first multi-mode superconducting qubit coupled to a second multi-mode superconducting qubit via a transmon qubit.

Abstract: A system for operation in a motor mode comprises a cryocooler to cool a superconducting coil of a rotor. The system further comprises a flux pump to provide flux to the superconducting coil to produce-a persistent current. Also, the system comprises a main stator coil. An alternating current within the main stator coil generates a rotating magnetic field, which interacts with the persistent current to generate an electromagnetic torque to rotate the rotor. The system also comprises a control stator coil to generate a current at a non-superconducting coil of the rotor. In one or more embodiments, a magnitude, phase, and/or frequency of the rotating magnetic field of the main stator coil and a magnetic field of the non-superconducting coil is varied in comparison a magnitude, phase, and/or frequency of the rotating magnetic field produced by the main stator coil alone to control a speed of the rotor.

Abstract: A microwave switch. In some embodiments, the microwave switch includes a substrate, a signal conductor, a first ground conductor, on a first side of the signal conductor, and a second ground conductor, on a second side of the signal conductor. The signal conductor, the first ground conductor, and the second ground conductor may be planar conductors on a planar top surface of the substrate. The signal conductor may have a first portion composed of a superconducting material, and a second portion having a reduced cross section, a cross-sectional area of the second portion being less than 120 nm.

Abstract: Methods and apparatus relating to clamping or reducing of dynamic capacitance for graphics logic are described. In one embodiment, utilization values for a plurality of subsystems of a graphics logic are determined and a first capacitance value is in turn determined based on (e.g., a sum of products of) the determined utilization values (e.g., and one or more capacitance weight values). A second capacitance value (e.g., corresponding to a maximum dynamic capacitance or Cdyn_max corresponding to the graphics logic) is modified based on (e.g., a comparison of the first capacitance value and a (e.g., threshold) capacitance value. Other embodiments are also disclosed and claimed.

Abstract: Systems and methods are provided for generating at least one high fidelity resource state. A classical code and punctured to provide a first set of generators and a second set of generators. The first set of generators is mapped to a set of stabilizer generators, and the second set of generators is mapped to a set of logical operators. A set of resource states are prepared in physical qubits. A decoding process is performed on the resource states according to a quantum code represented by the set of stabilizer generators and the set of logical operators, and qubits corresponding to the stabilizers are measured.

Abstract: Systems and methods are provided for generating a high-fidelity Toffoli state from a plurality of low-fidelity single qubit magic states. First and second qubits are prepared in a high-fidelity initial state. N target qubits are prepared in the single qubit magic state. A series of gates are performed on the qubits, such that the system is in a state ½|0001 . . . 0N+½|0101 . . . 0N+½|1001 . . . 0N+½|1111 . . . 1N. A parity check is performed on the N target qubits. The parity check provides at least a first measurement value. The first qubit, the second qubit, and the first target qubit are accepted as the Toffoli state if the measurement values assume the desired values.

Abstract: A radio frequency-assisted fast superconducting switch is described. A superconductor is closely coupled to a radio frequency (RF) coil. To turn the switch “off,” i.e., to induce a transition to the normal, resistive state in the superconductor, a voltage burst is applied to the RF coil. This voltage burst is sufficient to induce a current in the coupled superconductor. The combination of the induced current with any other direct current flowing through the superconductor is sufficient to exceed the critical current of the superconductor at the operating temperature, inducing a transition to the normal, resistive state. A by-pass MOSFET may be configured in parallel with the superconductor to act as a current shunt, allowing the voltage across the superconductor to drop below a certain value, at which time the superconductor undergoes a transition to the superconducting state and the switch is reset.

Abstract: Methods and apparatuses are provided for storing a quantum bit. One apparatus includes a first phase qubit, a second phase qubit, and a common bias circuit configured to provide a first bias to the first phase qubit and a second bias to the second phase qubit, such that noise within the first bias is anti-correlated to noise within the second bias.

Abstract: A pressure detection apparatus (30) detects, among a plurality of superconductor thin films (11 to 14) having different critical pressures at which a transition from a superconductor to an insulator occurs, the superconductor thin films (12 to 14) that have undergone the transition to the insulator with ammeters (242, 252, 262); and to detect, as an internal pressure of a housing (10), the maximum critical pressure among the critical pressures of the detected superconductor thin films (12 to 14).

Abstract: A control system architecture for quantum computing includes an array of qubits, which is divided into a plurality of sub-arrays based on a first direction and a second direction, the second direction intersecting the first direction, a plurality of control lines each coupled to a corresponding sub-array of qubits in the first direction, a plurality of enable/unenable lines each coupled to a corresponding sub-array of qubits in the second direction, a controls signal source that generates a control signal, wherein the control lines are used to apply the control signal commonly to one or more sub-arrays of qubits in the first direction, an enable/unenable signal source that generates a enable signal, wherein the enable/unenable lines are used to apply the enable signal independently to the corresponding sub-array of qubits in the second direction to set a bias point of each qubit of the corresponding sub-array of qubits in the second direction between a first position, in which the qubit is unenabled and not r

Abstract: A superconductor crossbar switch for connecting a plurality of inputs with a plurality of outputs, including a switching cell having an input, an output and a circuit for connecting the input with the output for bidirectionally transmitting data therebetween. The connection of the retaining and releasing circuitry of a plurality of cells enables the switch to simultaneously retain a selected cell or cells of a group of cells and disable the remaining cells of that group, whereby a subsequent query on a disabled cell is inoperative until the selected cell or cells is released. The crossbar switch is characterized by latency on the order of nanoseconds, a data rate per channel on the order of gigabits per second, essentially zero crosstalk, and detection of contention in nanoseconds or less and resolution of contention in nanoseconds or less.

Abstract: A single electron-transistor is used to read out charge states of two coupled qubits formed by two Cooper pair boxes. Detection is made about a gate voltage shift of the peak of the current that flows in the single electron transistor in accordance with the charge states. Since the current peak position varies depending on the particular charge state, all four charge states can be independently measured, or read out.

Abstract: A Superconducting Quantum Interference Device (SQUID) is disclosed comprising a pair of resistively shunted Josephson junctions connected in parallel within a superconducting loop and biased by an external direct current (dc) source. The SQUID comprises a semiconductor substrate and at least one superconducting layer. The metal layer(s) are separated by or covered with a semiconductor material layer having the properties of a conductor at room temperature and the properties of an insulator at operating temperatures (generally less than 100 Kelvins). The properties of the semiconductor material layer greatly reduces the risk of electrostatic discharge that can damage the device during normal handling of the device at room temperature, while still providing the insulating properties desired to allow normal functioning of the device at its operating temperature. A method of manufacturing the SQUID device is also disclosed.

Abstract: A field emission RF amplifier. The field emission RF amplifier includes one or more RF amplification units on a substrate and held in a vacuum state and facing a reflection electrode. The RF amplification unit includes a cathode electrode, gate electrode, and an anode electrode all formed on the same substrate. The cathode electrode has a CNT emitter. A DC voltages are applied to the cathode and anode electrodes. An RF signal is input at the cathode electrode and is amplified and output at the anode electrode. Capacitors and inductors are arranged to filter out AC and DC components where needed. An improved amplification of RF signals with high electron mobility and good impedance matching abilities result.

Abstract: A superconductor crossbar switch for connecting a plurality of inputs with a plurality of outputs, including a switching cell having an input, an output and a circuit for connecting the input with the output for bidirectionally transmitting data therebetween. The connection of the retaining and releasing circuitry of a plurality of cells enables the switch to simultaneously retain a selected cell or cells of a group of cells and disable the remaining cells of that group, whereby a subsequent query on a disabled cell is inoperative until the selected cell or cells is released. The crossbar switch is characterized by latency on the order of nanoseconds, a data rate per channel on the order of gigabits per second, essentially zero crosstalk, and detection of contention in nanoseconds or less and resolution of contention in nanoseconds or less.

Abstract: A method and apparatus for powering a high power load (on the order of 50,000 watts or more) can have an input from any of a plurality of different voltage sources, AC or DC. In one embodiment, the AC sources can have a frequency in the range of 16⅔-60 Hertz, and voltages in the range of 480-38,000 volts. The method and apparatus feature cryocooling inverter electronics, which converts an input signal to a high frequency high voltage signal, to, for example, less than about 180 K. A high frequency transformer receives the high frequency high voltage signal and transforms it into a desired voltage level which can then be filtered and/or demodulated and applied to the load. The transformer is preferably comprised of a superconducting material, and then, the inverter and transformer, at least, are actively cooled as required.

Abstract: A single-flux-quantum digital device includes a first superconducting line extended in a large ring, a second superconducting line connected to the first superconducting line, a superconducting single electron transistor for regulating a supercurrent flowing through the second superconducting line, and a small tunnel junction device for detecting a change in the supercurrent flowing through the first superconducting line. The first superconducting line is extended in a large ring. The second superconducting line divides the large ring into two small rings which are substantially the same in shape and area. The small tunnel junction device is connected to a point where the first and the second superconducting line are joined.

Abstract: An electronic power conversion circuit includes cryogenically cooled MOSFET power switching devices arranged in a switch-mode configuration and responsive to control signals for reducing capacitive discharge and commutation losses in the circuit by controlling the period between switch-on and switch-off time (i.e., “deadtime”) of the MOSFET devices. When one of the MOSFET devices of the circuit is switched off, the opposing MOSFET, after the short deadtime period, is switched on to serve as a commutating device rather, than the opposing MOSFET's intrinsic drain-source diode. The power conversion circuit may include a half-bridge circuit or combinations thereof.

Abstract: The present invention discloses a method for amplifying voltage to which a test will be given in Josephon junction having external current, and more particularly, to a method for amplifying voltage in Josephon junction in which the voltage in a simple Josephon junction having an external current can be amplified by inserting an external colored noise into the external current.

Abstract: A signal processing device comprises superconducting wiring for providing an output signal or a transmitted signal correctly corresponding to an input signal without increasing the temperature of the device. The signal processing device has a signal input end, a signal output end, and proper signal processing circuits interposed between the signal input and output ends. The superconducting wiring connects the signal input end with the signal output end. An output end of the wiring is open, and the length of the wiring is set to be approximately 25% of the product of the pulse width and the phase velocity of the signal transmitted through the wiring.

Abstract: A cryogenically cooled circuit, operating at temperatures at which inductors windings of the circuit exhibit superconducting characteristics, provides unique advantages in high performance, preferably high power circuits. Portions of the circuit (or the entire circuit), as opposed to, for example only the superconducting elements (i.e., inductor winding), are refrigerated to cryogenic temperatures. Advantages in the characteristics of not only the superconducting based components but also the diodes, and gating elements such as MOSFET's, yield a uniquely advantageous circuit enabling the operation of, for example, a switching power supplies, frequency converters, and motor speed controllers with increased performance and efficiency. Size, component count, and stability are benefits attained by cryogenically cooling the entire circuit configuration.

Abstract: In a superconducting energy storage apparatus including an AC-DC converter unit, a superconducting coil, a quench protection unit and a mechanical type persistent current switch, a self-firing type thyristor switch is connected in parallel to the mechanical type persistent current switch to be first operated in the event of an occurrence of trouble in an associated electric power system, and a control unit generates an ON instruction signal for turning on the persistent current switch so as to immediately establish a persistent current mode.

Abstract: A hybrid superconducting-semiconducting field effect transistor-like circuit element comprised of a superconducting field effect transistor and a closely associated cryogenic semiconductor inverter for providing signal gain is described. The hybrid circuit functions nearly as an ideal pass gate in cryogenic cross-bar applications.