One example includes a current device readout system. The system includes a tunable resonator having a resonant frequency that is associated with a current state of a current device. The tunable resonator can be configured to receive a tone signal having a predetermined frequency from a feedline to determine the current state of the current device. The system also includes an isolation device inductively interconnecting the tunable resonator and the current device. The isolation device can be tunable to isolate the current device in a first state and to facilitate the determination of the current state of the current device in a second state.

One example includes a current device readout system. The system includes a tunable resonator having a resonant frequency that is associated with a current state of a current device. The tunable resonator can be configured to receive a tone signal having a predetermined frequency from a feedline to determine the current state of the current device. The system also includes an isolation device inductively interconnecting the tunable resonator and the current device. The isolation device can be tunable to isolate the current device in a first state and to facilitate the determination of the current state of the current device in a second state.

A quantum computing device includes multiple co-planar waveguide flux qubits, at least one coupler element arranged such that each co-planar waveguide flux qubit, of the multiple co-planar waveguide flux qubits, is operatively couplable to each other co-planar waveguide flux qubit, of the multiple co-planar waveguide flux qubits, of the quantum computing device, and a tuning quantum device, in which the tuning quantum device is in electrical contact with a first co-planar waveguide flux qubit of the plurality of co-planar waveguide flux qubits and with a second co-planar waveguide flux qubit of the plurality of co-planar waveguide flux qubits.

A magnetometer for measuring a magnetic flux and also the absolute magnetic flux, the magnetometer comprising a plurality of superconducting quantum devices (SQUIDs) connected in series, each SQUID including: a superconducting loop containing two Josephson junctions connected to each other in parallel; and a flux-focussing region, the flux-focussing region configured to generate a screening current in response to the magnetic flux, the screening current modulating the corresponding voltage response for each SQUID which is in-phase with the voltage response of each other SQUID in the array.

An objective of the present invention is to provide a biomagnetism measurement device capable of three-dimensionally acquiring magnetism information of a living body with ease. This biomagnetism measurement device (101) is for measuring biomagnetism using a plurality of magnetic sensors (1) at the same time. The plurality of magnetic sensors (1) is retained by a retaining part (100) (a first retaining portion [11] and a second retaining portion [12]) so as to have different measurement directions. Furthermore, the retaining part (10) (the first retaining portion [11] and the second retaining portion [12]) has arranged thereon the plurality of magnetic sensors (1) so as to enable biomagnetism to be measured at a plurality of sites at the same time. The magnetic sensor (1) comprises a means for detecting the biomagnetism in a temperature environment commensurate with normal temperature.

First and second superconductive sensors receive an electromagnetic signal. The first and second superconductive sensors are spaced apart such that there is a phase difference between the electromagnetic signal as received at the first and second superconductive sensors. The first and second superconductive sensors output respective first and second voltage signals corresponding to the electromagnetic signal as received by the first and second superconductive sensors. A nonlinear detector detects a voltage difference between the first and second voltage signals and provides an output signal representing the detected voltage difference. The output signal corresponds to the phase difference between the electromagnetic signal as received at the first and second superconductive sensors.

First and second superconductive sensors receive an electromagnetic signal. The first and second superconductive sensors are spaced apart such that there is a phase difference between the electromagnetic signal as received at the first and second superconductive sensors. The first and second superconductive sensors output respective first and second voltage signals corresponding to the electromagnetic signal as received by the first and second superconductive sensors. A nonlinear detector detects a voltage difference between the first and second voltage signals and provides an output signal representing the detected voltage difference. The output signal corresponds to the phase difference between the electromagnetic signal as received at the first and second superconductive sensors.

Disclosed a quench protection device of a superconducting magnet system, including a superconducting coil set; the superconducting coil set comprises two superconducting coils(5) which are symmetrical arranged, and each of the two superconducting coils(5) is connected in parallel with a protection diode(4); the superconducting coils and the protection diode are connected with the power supply via a conductive wire; the superconducting coils set are connected in parallel with a quench protection unit(6), a change-over switch(3) is arranged on a circuit of the two superconducting coils, the protection diode, and the power supply, and the change-over switch(3) is connected with an external resistor via a conductive wire (2). The change-over switch of the quench protection device connects the superconducting coil and an external resistance, which realizes the quench protection of the superconducting coil.

In a general aspect, a superconducting quantum circuit system is modeled. In some aspects, a graph representing a quantum circuit system is generated. The graph includes vertices and edges; the edges represent circuit elements of the quantum circuit system, and the vertices represent physical connections between the circuit elements. Inverse inductances, conductances, capacitances, and junction inverse inductances are assigned to respective edges of the graph based on a lumped-element approximation of the quantum circuit system. A coordinate system is determined based on the graph, and a matrix representation of the system is determined based on the coordinate system. A Hamiltonian for the quantum circuit system is determined using the matrix representation, and the quantum circuit system is simulated based on the Hamiltonian.

In a general aspect, a superconducting quantum circuit system is modeled. In some aspects, a graph representing a quantum circuit system is generated. The graph includes vertices and edges; the edges represent circuit elements of the quantum circuit system, and the vertices represent physical connections between the circuit elements. Inverse inductances, conductances, capacitances, and junction inverse inductances are assigned to respective edges of the graph based on a lumped-element approximation of the quantum circuit system. A coordinate system is determined based on the graph, and a matrix representation of the system is determined based on the coordinate system. A Hamiltonian for the quantum circuit system is determined using the matrix representation, and the quantum circuit system is simulated based on the Hamiltonian.