Abstract: In a coil device with at least one electrical coil winding with superconducting conductor material, the coil winding is part of a self-contained circuit for formation of a continuous current. The closed circuit has a switchable conductor section which can be switched between a superconducting state and a normally conducting state by a magnetic device.

Abstract: A method of forming a magnetic tunnel junction device is disclosed that includes forming a trench in a substrate, the trench including a plurality of sidewalls and a bottom wall. The method includes depositing a first conductive material within the trench proximate to one of the sidewalls and depositing a second conductive material within the trench. The method further includes depositing a material to form a magnetic tunnel junction (MTJ) structure within the trench. The MTJ structure includes a fixed magnetic layer having a magnetic field with a fixed magnetic orientation, a tunnel junction layer, and a free magnetic layer having a magnetic field with a configurable magnetic orientation. The method further includes selectively removing a portion of the MTJ structure to create an opening in the MTJ structure.

Abstract: Computing bus devices that enable quantum information to be coherently transferred between topological and conventional qubits are disclosed. A concrete realization of such a topological quantum bus acting between a topological qubit in a Majorana wire network and a conventional semiconductor double quantum dot qubit is described. The disclosed device measures the joint (fermion) parity of the two different qubits by using the Aharonov-Casher effect in conjunction with an ancillary superconducting flux qubit that facilitates the measurement. Such a parity measurement, together with the ability to apply Hadamard gates to the two qubits, allows for the production of states in which the topological and conventional qubits are maximally entangled, and for teleporting quantum states between the topological and conventional quantum systems.

Abstract: A method of forming a magnetic tunnel junction device is disclosed that includes forming a trench in a substrate, the trench including a first sidewall, a second sidewall, a third sidewall, a fourth sidewall, and a bottom wall. The method includes depositing a first conductive material within the trench proximate to the first sidewall and depositing a second conductive material within the trench. The method further includes depositing a magnetic tunnel junction (MTJ) structure within the trench. The MTJ structure includes a fixed magnetic layer having a magnetic field with a fixed magnetic orientation, a tunnel junction layer, and a free magnetic layer having a magnetic field with a configurable magnetic orientation. The method further includes selectively removing a portion of the MTJ structure that is adjacent to the fourth sidewall to create an opening such that the MTJ structure is substantially u-shaped.

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 superconducting junction element has a lower electrode formed by a superconductor layer, a barrier layer provided on a portion of a surface of the lower electrode, an upper electrode formed by a superconductor and covering the barrier layer, and a superconducting junction formed by the lower electrode, the barrier layer and the upper electrode. A critical current density of the superconducting junction is controlled based on an area of the lower electrode.

Abstract: A method for determining whether a quantum system comprising a superconducting qubit is occupying a first basis state or a second basis state once a measurement is performed is provided. The method, comprising: applying a signal having a frequency through a transmission line coupled to the superconducting qubit characterized by two distinct, separate, and stable states of differing resonance frequencies each corresponding to the occupation of the first or second basis state prior to measurement; and measuring at least one of an output power or phase at an output port of the transmission line, wherein the measured output power or phase is indicative of whether the superconducting qubit is occupying the first basis state or the second basis state.

Abstract: A twisted track interferometer (TTI) for producing magic states is disclosed. The spin of ½-vortices may be exploited to produce magic states. The disclosed “twisted track interferometer” is a “topological twist” on the conventional Pabre-Pero interferometer adapted to topological superconductors. In the disclosed TTI, the probe particles may be Josephson vortices (JVs). JVs are estimated to be light and will tunnel more easily than Abrikosov vortices. Also, the disclosed TTI does not require multiple tunneling events. Rather, the JVs are propelled down thin insulating tracks within a 2D topological p-wave superconductor by a Magnus force generated by a tunneling supercurrent across the tracks. The JVs encounter tunneling junctions as they pass into the arms of the TTI.

Abstract: A ladder structure is ferromagnetically coupled to a first qubit where the ladder structure has a monostable energy potential in use, such that the first qubit and the ladder structure effectively operate as a single qubit. The ladder structure and first qubit may be coupled via a superconducting flux coupler. The ladder structure may be a chain of at least two ferromagnetically coupled ladder elements. A value for each ladder element may be less than about 1.

Abstract: A method for determining whether a quantum system comprising a superconducting qubit is occupying a first basis state or a second basis state once a measurement is performed is provided. The method, comprising: applying a signal having a frequency through a transmission line coupled to the superconducting qubit characterized by two distinct, separate, and stable states of differing resonance frequencies each corresponding to the occupation of the first or second basis state prior to measurement; and measuring at least one of an output power or phase at an output port of the transmission line, wherein the measured output power or phase is indicative of whether the superconducting qubit is occupying the first basis state or the second basis state.

Abstract: A method for determining whether a quantum system comprising a superconducting qubit is occupying a first basis state or a second basis state once a measurement is performed is provided. The method, comprising: applying a signal having a frequency through a transmission line coupled to the superconducting qubit characterized by two distinct, separate, and stable states of differing resonance frequencies each corresponding to the occupation of the first or second basis state prior to measurement; and measuring at least one of an output power or phase at an output port of the transmission line, wherein the measured output power or phase is indicative of whether the superconducting qubit is occupying the first basis state or the second basis state.

Abstract: A ladder structure is ferromagnetically coupled to a first qubit where the ladder structure has a monostable energy potential in use, such that the first qubit and the ladder structure effectively operate as a single qubit. The ladder structure and first qubit may be coupled via a superconducting flux coupler. The ladder structure may be a chain of at least two ferromagnetically coupled ladder elements. A value for each ladder element may be less than about 1.

Abstract: A qubit implementation based on exciton condensation in capacitively coupled Josephson junction chains is disclosed. The qubit may be protected in the sense that unwanted terms in its effective Hamiltonian may be exponentially suppressed as the chain length increases. Also disclosed is an implementation of a universal set of quantum gates, most of which offer exponential error suppression.

Abstract: A method for determining whether a quantum system comprising a superconducting qubit is occupying a first basis state or a second basis state once a measurement is performed is provided. The method, comprising: applying a signal having a frequency through a transmission line coupled to the superconducting qubit characterized by two distinct, separate, and stable states of differing resonance frequencies each corresponding to the occupation of the first or second basis state prior to measurement; and measuring at least one of an output power or phase at an output port of the transmission line, wherein the measured output power or phase is indicative of whether the superconducting qubit is occupying the first basis state or the second basis state.

Abstract: A Josephson quantum computing device and an integrated circuit using Josephson quantum computing devices which can realize a NOT gate operation controlled with 2 bits will be provided. The Josephson quantum computing device (1) comprises: a superconducting ring member (10) having a ?-junction (6) and a 0-junction (7); and a quantum state detecting member (20) constituted by a superconducting quantum interference device arranged outside of the superconducting ring member, wherein a bonding and an antibonding state brought about by a tunneling effect between a |?> and a |?> state as two states degenerate in energy of the superconducting ring member (10) are regarded as quantum bits. The bonding and antibonding states as the quantum bits are read out by the quantum state detecting member (20). The two bit controlled NOT gate operation can be performed by the two quantum bits comprising said quantum bits.

Abstract: A superconducting readout system includes a computation qubit; a measurement device to measure a state of the computation qubit; and a latch qubit that mediates communicative coupling between the computation qubit and the measurement device. The latch qubit includes a qubit loop that includes at least two superconducting inductors coupled in series with each other; a compound Josephson junction that interrupts the qubit loop that includes at least two Josephson junctions coupled in series with each other in the compound Josephson junction and coupled in parallel with each other with respect to the qubit loop; and a first clock signal input structure to couple clock signals to the compound Josephson junction.

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 directions 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