39 results about "Superconducting loop" patented technology

A device comprises a superconducting quantum bit, and a tunable readout resonator coupled to the superconducting quantum bit. The tunable readout resonator comprises a fixed resonator and a tunable element which is coupled to the fixed resonator and which is configured for flux-tuning the tunable readout resonator into at least one of a first state and a second state. The tunable element comprises a superconducting loop which comprises at least two asymmetric Josephson junctions. In the first state, the tunable readout resonator comprises a first resonant frequency that differs from a transition frequency of the superconducting quantum bit by a first detuning value. In the second state, the tunable readout resonator comprises a second resonant frequency that differs from the transition frequency of the superconducting quantum bit by a second detuning value, which is less than the first detuning value.

Systems, methods, and apparatus for multiplexed control and readout of quantum computing systems that can include qubits, couplers, and other related quantum computing circuit devices. Numerous examples of superconducting quantum computing systems are described that include some, or all, of these quantum computing circuit devices integrated into a superconducting quantum circuit that can be interfaced by a classical control system. In one example, a superconducting circuit is described. The superconducting circuit includes: a superconducting device including a superconducting loop interrupted by one or more Josephson junctions; a first microwave resonator inductively coupled to the superconducting loop of the superconducting device; a second microwave resonator capacitively coupled to the superconducting device, where the first and second microwave resonators each have a different fundamental frequency; and a microwave transmission line evanescently coupled to each of the first and second microwave resonators.

According to the structure for reducing the area of the SQUID superconducting loop and the preparation method thereof provided by the invention, the laminated structure is formed on the silicon substrate, and then the laminated structure is accurately etched, so that the 3D nano bridge junction is formed on the slope surface of the laminated structure and stretches across the insulating layer, and therefore, batch preparation of the structure for reducing the area of the SQUID superconducting loop can be realized; according to the SQUID probe, large-scale application of the SQUID probe is more facilitated, the plane of the 3D nanometer bridge junction is perpendicular to the plane where the SQUID superconducting loop is located, so that the width of the 3D nanometer bridge junction does not influence the effective loop area of the SQUID any more, the performance of the SQUID can be improved by independently regulating and controlling the thickness of the 3D nanometer bridge junction, the inhibition effect of a magnetic field on the superconducting characteristic of the 3D nanometer bridge junction is greatly weakened, and in addition, the SQUID probe can be applied to a large scale. The SQUID superconducting loop with the minimum line width of 10nm can be prepared by combining the electron beam lithography technology with higher precision, the area of the SQUID superconducting loop can be greatly reduced, and the spin sensitivity is improved, so that higher spatial resolution can be realized during scanning magnetic imaging.

A device comprises a switch circuit and control lines. The switch circuit comprises a plurality of signal input / output ports, and a plurality of switch nodes, each switch node comprising a superconducting loop which comprises a plurality of Josephson junctions arranged in a ring configuration. The control lines are configured to selectively apply flux bias control signals to the switch nodes. The plurality of switch nodes is arranged to selectively configure a signal routing path between any pairwise combination of signal input / output ports of the plurality of signal input / output ports, in response to flux bias control signals selectively applied to the switch nodes.

The invention relates to a microwave signal amplifier comprising a chain of nonlinear inductive dipole elements each forming an asymmetric superconducting loop with Josephson junctions, said chain being arranged between an input of the chain for applying a signal to be amplified and an output of the chain at which an output signal is developed, the amplifier further comprising a controllable magnetic flux generation system for circulating a current in said loops, the amplifier further comprising a first microwave pump and means for coupling said input of the chain to the first pump, the first pump generating through the first coupling means a wave in the chain in the direction from the input to the output of frequency adjusted to transfer power at the frequency of the signal to be amplified.The device further comprises a second microwave pump and a second means for coupling said output of the chain to said second pump, the second pump generating through the second coupling means a wave in the chain in the direction from the output to the input, at a frequency different from that of the first pump and so as to attenuate in said direction from the output to the input the microwaves propagating at the frequency of the signal to be amplified. Figure for the abstract: Fig. 1.

The present disclosure relates to a two-step gradient independent input feedback type superconducting quantum interference device and a preparation method thereof, including: eight superconducting pads, the eight superconducting pads include four input superconducting pads and four negative feedback superconducting pads, one input superconducting pad and one negative feedback superconducting pad form a superconducting loop, and the four superconducting loops are connected in parallel and arranged in a centrosymmetric manner; an input coil, the input coil is coupled with the four superconducting input superconducting pads; a negative feedback coil, the negative feedback coil is coupled with the four negative feedback superconducting pads. The present disclosure can effectively reduce the crosstalk phenomenon between the input coil and the feedback coil, and improve the coupling coefficient and transmission efficiency of the input coil and the feedback coil.

The present disclosure relates to a second-order gradient independent input feedback superconducting quantum interference device and a preparation method thereof, comprising: eight superconducting pads, the eight superconducting pads comprising four input superconducting pads and four negative feedback superconducting pads, one input superconducting pad and one negative feedback superconducting pad forming one superconducting loop, the four superconducting loops being in parallel and arranged in a central symmetry; an input coil, the input coil being coupled with the four input superconducting pads; and a negative feedback coil, the negative feedback coil being coupled with the four negative feedback superconducting pads. The present disclosure can effectively reduce the crosstalk phenomenon between the input coil and the feedback coil, and improve the coupling coefficient and the transfer efficiency of the input coil and the feedback coil.

A persistent current switch is disclosed for controlling, e.g. initiating, a persistent current in a superconductor loop. The persistent current switch comprises a piece of superconductor material that is part of the superconductor loop. Further, the persistent current switch comprises an illumination system that is configured to direct light onto the piece of superconductor material for influencing an electrical resistance of the piece of superconductor material. The illumination system is configured such that the light impinging on the piece of superconductor material substantially does not heat the piece of superconductor material.

The invention relates to a frequency-adjustable superconducting quantum coupler capable of naturally resisting magnetic flux noise, which comprises a DC-SQUIDs (Direct Current-Superconducting Quantum IDs), namely a superconducting ring consisting of two Josephson junctions, a bias control line for adjusting the critical current of the SQUIDs, and a capacitor or inductance circuit component adapted to adjust coupling parameters, the DC-SQUIDs are of a planar inner loop structure, the loop comprises two Josephson junctions, two arms of the SQUIDs are mutually crossed to form 2N identical superconducting loops, namely sub-loops, and N is a positive integer; the bias control line changes the magnetic flux in the loop by applying a bias magnetic field, so that the critical current of the SQUIDs is changed, and then the frequency of the superconducting quantum coupler can be regulated and controlled. In the process of actively adjusting the frequency of the coupler, the induced current of the N sub-loops in the SQUIDs flows clockwise, and the induced current of the other N sub-loops flows anticlockwise, so that a loop is integrally formed.

There is provided a system (1) for hosting a bosonic qubit, comprising a non-linear superconducting circuit (3) and a command circuit (5). The non-linear superconducting circuit (3) comprises: at least one resonant portion (9), and an asymmetrically threaded superconducting quantum interference device (ATS) (7) coupled to said at least one resonant portion (9), wherein the ATS (7) comprises a pair of Josephson junctions and an inductive element, wherein the pair of Josephson junctions and the inductor are galvanically connected in parallel such that each of the Josephson junctions respectively forms first and second superconducting loops with the inductive element, wherein the non-linear superconducting circuit has a first physical oscillatory mode for hosting the bosonic qubit, the first physical oscillatory mode having a first resonant frequency. The command circuit (5) comprises a first electromagnetic source (27) configured to thread the first superconducting loop with a first magnetic flux Φ 1 and the second superconducting loop with a second magnetic flux Φ 2 such that the ATS (7) is threaded with a differential flux (formula I) in units of the superconducting flux quantum. The command circuit (5) is further configured to modulate the differential flux (formula II) at a modulation frequency equal to the first resonant frequency ωa.

A device comprises a superconducting switch which comprises an impedance tunable element coupled to and between a transmission line and ground. The transmission line couples a first port and a second port having matched impedances. The impedance tunable element comprises a superconducting loop comprising at least one Josephson junction, and is configured to be flux tuned into a first or second impedance state. In the first impedance state, the impedance tunable element shunts the transmission line to ground with an impedance that disrupts the impedance match between the first and second ports to suppress signal transmission between the first and second ports over the transmission line. In the second impedance state, the impedance tunable element shunts the transmission line to ground with an impedance that maintains the impedance match between the first and second ports to allow signal transmission between the first and second ports over the transmission line.

The invention discloses a field cold excitation closed-loop operation high-temperature superconducting magnet device with magnetic flux density bidirectional amplification and magnetic flux accumulation functions, and belongs to the technical field of superconducting magnet application. The high-temperature superconducting magnet device comprises a plurality of single-communication three-hole closed-loop superconducting sheet stacking units; wherein a first circular hole, a second circular hole and a third circular hole are formed in the single-communication three-hole closed-loop superconducting sheet, and slits are formed between the first circular hole and the second circular hole and between the second circular hole and the third circular hole; the single-connection three-hole closed-loop superconducting sheet is sleeved on the solenoid through the first round hole and the third round hole; and the plurality of single-communication three-hole closed-loop superconducting sheet stacking units are uniformly distributed in the circumferential direction by taking the second circular hole as the center. The device is composed of a full-superconducting loop, is simple in structure, does not need welding, a power supply and a current lead, can stably output a required high-intensity magnetic field, and is widely applied to a steady-state high-intensity magnetic field occasion.

A first superconducting device includes two first adjacent superconducting qubits and a superconducting loop disposed between and inductively coupled to the two first adjacent superconducting qubits. The superconducting loop includes a first hotspot nanowire that is in a superconducting state when a bias current is less than a critical current and in a high resistive state when the bias current is not less than the critical current. A second superconducting device includes two second adjacent superconducting qubits and a superconducting lead extending from one superconducting qubit to the other and being capacitively coupled to the two second adjacent superconducting qubits. The superconducting lead includes a second hotspot nanowire that is in a superconducting state when a bias current is less than a critical current and in a high resistive state when the bias current is not less than the critical current.

This solves the connectivity problem between qubits. [Solution] The superconducting integrated circuit includes a first superconducting device 102 having a first superconducting loop 108 with a first superconducting trace in a first layer of the superconducting integrated circuit, and a second superconducting device 104 having a second superconducting loop 112 with a second superconducting trace in a second layer. The first superconducting loop intersects with the second superconducting loop in an intersection region 120. At least a portion of each of the first and second superconducting traces inside the intersection region follows a detour path that is narrower than at least a portion of each of the traces outside the intersection region and inductively approaches at least a portion of the other path.

The invention discloses a frequency-adjustable superconducting quantum bit capable of naturally resisting magnetic flux noise. The frequency-adjustable superconducting quantum bit comprises a direct-current equal-arm SQUIDs and a bias control line for adjusting the critical current of the SQUIDs, the SQUIDs of the direct current equal arms are of a standard in-plane loop structure, and the two arms of the SQUIDs intersect with each other to form 2N identical superconducting loops, namely sub-loops. The bias control line changes the magnetic flux in the loop by applying a bias magnetic field, so that the critical current of the SQUIDs is changed, and the frequency of the superconducting quantum bits can be regulated and controlled; on the basis of the SQUIDs structure of a direct-current equal arm, the space geometric structure of the SQUIDs is improved, so that magnetic flux noise entering a loop of the SQUIDs is mutually counteracted, and net magnetic flux accumulated in the loop due to the magnetic field noise is zero. When N is equal to 1, magnetic flux disturbance in the two sub-loops is phi 0 and-phi 0 respectively, and the phi 0 and the-phi 0 counteract each other, so that the superconducting critical current of the SQUIDs cannot be interfered, and the capability of eliminating the magnetic flux noise by bits is realized.

The present invention provides a Josephson measurement system and a measurement method, comprising an excitation coil, a sample superconducting loop and a superconducting detector structure; the excitation coil is connected to an excitation current and generates an excitation magnetic flux, and the sample superconducting loop generates a phase between two ends of the sample Josephson junction and a superconducting current of the sample superconducting loop according to the excitation magnetic flux; the superconducting detector structure obtains an output voltage according to the superconducting magnetic flux output; wherein, based on the relationship between the excitation magnetic flux and the excitation current and the relationship between the excitation magnetic flux and the phase between two ends of the sample Josephson junction, the relationship between the phase of the sample Josephson junction and the excitation current can be obtained; and the relationship between the phase of the sample Josephson junction and the superconducting current can be obtained according to the output voltage, the excitation current, the superconducting current and the relationship between the phase of the sample Josephson junction and the excitation current. The present invention can accurately obtain complete information of the Josephson junction.

The invention discloses an SQUID-based inner centering superconductive gravity measurement device and method, and belongs to the technical field of gravity measurement, the device comprises an SQUID, an input coil, a detection cavity, a superconductive suspension body, a torquer cavity, a suspension coil and a coil support base which are arranged from top to bottom; the input coil and the detection coil are in superconducting connection to form a detection loop; the detection coil induces the vertical displacement of the superconducting suspension body and converts the vertical displacement into a current signal, and the current signal is coupled to the input coil in magnetic flux coupling with the SQUID through the detection loop; the SQUID converts the magnetic flux change into a voltage signal and outputs the voltage signal, so that high-precision detection of displacement is realized; a detection coil is arranged in the detection cavity, and a torquer is arranged in the torquer cavity; different currents are introduced into the first torque superconducting loop and the second torque superconducting loop of the torquer, so that the inclination state of the superconducting suspension body is adjusted. According to the invention, the problem of poor stability of high-precision dynamic gravity measurement is effectively solved.

The invention discloses a multi-ring high-temperature superconducting permanent magnet device. The device has magnetic flux density amplification and magnetic flux accumulation functions. The device comprises a plurality of single-communication four-hole closed-loop superconducting sheet stacking units, wherein the single-communication four-hole closed-loop superconducting sheet stacking unit comprises a plurality of stacked single-communication four-hole closed-loop superconducting sheets and solenoids; a first circular hole, a second circular hole, a third circular hole and a fourth circular hole are formed in the single-communication four-hole closed-loop superconducting sheet, and slits are formed between the first circular hole and the second circular hole, between the second circular hole and the third circular hole and between the third circular hole and the fourth circular hole; the two solenoids are sleeved with the single-communication four-hole closed-loop superconducting piece through the second round hole and the third round hole respectively. And the plurality of single-communication four-hole closed-loop superconducting sheet stacking units are uniformly distributed in the circumferential direction by taking the second circular hole and the third circular hole as centers. The device is composed of a full superconducting loop, is simple in structure, does not need welding, a power supply and a current lead, can stably output a required strong magnetic field, and can also be applied to occasions such as medium and large superconducting magnets.

A superconducting memory device includes: at least two superconducting loops, one configured as a readout loop and another configured as a state loop; a non-superconducting input conveying a non-superconducting input signal for writing state to the memory device; at least two superconducting inputs conveying superconducting input signals for reading the state of the memory device; a superconducting output conveying an output of the memory device; first and second Josephson junctions, the state loop including the first Josephson junction, the readout loop including the second Josephson junction; and a non-superconducting write circuit including a write line for conveying a write signal for writing state to the memory device. A state of the memory device is determined based on the presence of single flux quantum in the state loop, a location of the single flux quantum in the superconducting loops, or a direction of rotation of the single flux quantum in the state loop.

Provided are a structure for reducing a SQUID superconducting loop area, and a preparation method therefor, wherein a stacked structure is formed on a silicon substrate, and precision etching is performed on the stacked structure, so that a 3D nano-bridge junction is formed on a sloped surface of the stacked structure and stretches across an insulating layer, such that batch preparation of the structure for reducing a SQUID superconducting loop area can be implemented, which facilitates large-scale application of SQUID probes. The plane of the 3D nano-bridge junction is perpendicular to the plane on which a SQUID superconducting loop is located, such that the width of the 3D nano-bridge junction no longer affects a SQUID effective loop area, so that the thickness of the 3D nano-bridge junction can be individually regulated in order to improve SQUID performance, which significantly weakens the inhibition effect of a magnetic field on the superconducting characteristics of the 3D nano-bridge junction. In addition, the SQUID superconducting loop having a minimum line width of 10nm can be prepared in combination with an electron beam lithography technique having higher precision, significantly reducing the SQUID superconducting loop area, improving spin sensitivity, and thereby achieving higher spatial resolution during scanning magnetic imaging.

The present invention discloses a high-temperature superconducting permanent magnet device with magnetic flux density amplification and magnetic flux accumulation functions, which belongs to the field of superconducting magnet application technology. The high-temperature superconducting permanent magnet device includes a plurality of single-connected double-hole closed-loop superconducting sheet stacking units; wherein the single-connected double-hole closed-loop superconducting sheet stacking unit includes a plurality of stacked single-connected double-hole closed-loop superconducting sheets and a solenoid; a first circular hole and a second circular hole are opened on the single-connected double-hole closed-loop superconducting sheet, and a slit is provided between the first circular hole and the second circular hole; the single-connected double-hole closed-loop superconducting sheet is sleeved on the solenoid through the first circular hole; and a plurality of single-connected double-hole closed-loop superconducting sheet stacking units are evenly distributed in the circumferential direction with the second circular hole as the center. The present invention is composed of a full superconducting circuit, has a simple structure, can stably output the required strong magnetic field, and is widely used in steady-state strong magnetic field occasions.

A method, and a corresponding system, are disclosed for measuring a direction, and optionally also a magnitude, of current in a flux qubit. The method comprises providing a probe signal to a resonator circuit having a resonance frequency. The probe signal transmits through or reflects from the resonator circuit. Further, the resonator circuit comprises a superconducting loop interrupted by a first Josephson junction and by a second Josephson junction. The first Josephson junction and second Josephson junction are connected in parallel. The superconducting loop is positioned such that it is inductively coupled to the flux qubit. The method further comprises measuring the reflected probe signal that has reflected from the resonator circuit or, respectively, measuring the transmitted probe signal that has transmitted through the resonator circuit. The method also comprises, based on a difference, such as a phase difference or amplitude difference, between the probe signal and the reflected probe signal or, respectively, between the probe signal and the transmitted probe signal, determining the direction of current in the flux qubit.

The present disclosure relates to a qubit device comprising a first superconducting loop containing one Josephson junction, and a second superconducting loop having an inductance higher than an inductance of the first superconducting loop.

Memory devices based on Josephson junctions and methods of using the same are described herein. An example of a Josephson junction-based memory device includes a plurality of superconducting loops. Each superconducting loop includes at least one Josephson junction. The plurality of superconducting loops are electrically coupled. The plurality of superconducting loops includes a plurality of input loops, a plurality of readout loops, and at least one shared loop. The plurality of superconducting loops are configured to store or eliminate magnetic flux quanta in the one or more superconducting loops in response to a combination of a control signal and a single flux quantum (SFQ) pulse.

The present invention is a system that produces zero noise magnetic field, which consists of: a coil made of superconducting wire, a precision current source, a Normally Closed Reed (NC) Relay, a Normally Opened (NO) Reed Relay, a cooling mechanism to maintain the superconductor temperature below the critical temperature. The precision current source generates the necessary initial current to act as source for the superconducting coil. The NO reed relay connects the precision current source to the superconductive coil. When this current start to flow, the NC Relay is used to close a superconductive path of the superconductive coil on to itself. Once the system becomes stabilized, the NO reed relay is made open, cutting off the precision source while the Normally Closed relay is closed, thereby a steady value current keeps flowing inside the superconducting coil with zero resistance and zero magnetic noise.

The application provides a magnetic field strength-plane gradient composite plane magnetic detector, and relates to a magnetic detector, which comprises a superconducting layer, a magnetoresistance layer and a soft magnetic layer. The superconducting layer is composed of two identical closed superconducting loops connected together, the two closed superconducting loops have ring holes with the same size at the centers, the two closed superconducting loops and the common area connected together each comprise a current compression structure, the magnetoresistance layer is located above the current compression structure of the superconducting layer, the soft magnetic layer is a rectangular structure, two rectangular structures are located above the superconducting layer, one rectangular structure is located below the superconducting layer, and the one rectangular structure overlaps with the two rectangular structures above the superconducting layer at the position of the ring hole of the superconducting layer. The application overcomes the problem that the existing magnetic detector cannot simultaneously measure the magnetic field strength and the magnetic field gradient in different directions, and provides a new magnetic field strength-gradient composite magnetic detector.

Josephson junction based memory devices and methods for their use are described herein. An example Josephson junction based memory device includes a plurality of superconducting loops. Each superconducting loop includes at least one Josephson junction. The plurality of superconducting loops are electrically coupled. The plurality of superconducting loops include a plurality of input loops, a plurality of readout loops, and at least one shared loop. The plurality of superconducting loops are configured to store or annihilate magnetic flux quanta in one or more of the superconducting loops in response to a combination of control signals and single flux quantum (SFQ) pulses.

A superconducting circuit includes four superconducting qubits communicatively coupled by a 4-qubit even-parity stabilizer. The 4 -qubit even-parity stabilizer includes a superconducting stabilizer loop, and four inductances, each inductance inductively communicatively coupled to an inductance of a respective one of the four superconducting qubits. The 4-qubit even-parity stabilizer also includes a parity-enforcing super-conducting qubit communicatively coupled to the superconducting loop. A quantum processor comprises four Josephson parametric amplifiers communicatively coupled by a 4-qubit even-parity stabilizer. The Josephson parametric amplifiers comprise pairs of superconducting microwave resonators communicatively coupled by a compound-compound Josephson junction. The 4-qubit even-parity stabilizer includes a superconducting loop, four inductances inductively communicatively coupled to an inductance of a respective one of the four Josephson parametric amplifier, and a parity-enforcing Josephson parametric amplifier communicatively coupled to the superconducting loop.

A superconducting qubit processor includes a plurality of fluxonium superconducting loop-based qubit devices, the fluxonium qubit devices arranged and connected in a lattice with a capacitive coupling between neighbour fluxonium qubit devices in the lattice; the fluxonium-based qubit devices divided in a first group of first type fluxonium qubits as control qubits and a second group of second type fluxonium qubits as target qubits, such that in the lattice each first type fluxonium qubit is neighboured by a second type fluxonium qubit and vice versa; the first type fluxonium qubits having a first qubit frequency and the second type fluxonium qubits having a second qubit frequency; the first and second qubit frequency being defined by structural parameters of the first and the second type fluxonium qubit, respectively; the first qubit frequency having a value between about 30% and about 50% of the value of the second qubit frequency.

The invention discloses a multi-ring high-temperature superconducting permanent magnet device. The device has magnetic flux density amplification and magnetic flux accumulation functions. The device comprises a plurality of single-communication four-hole closed-loop superconducting sheet stacking units, wherein the single-communication four-hole closed-loop superconducting sheet stacking unit comprises a plurality of stacked single-communication four-hole closed-loop superconducting sheets and solenoids; a first circular hole, a second circular hole, a third circular hole and a fourth circular hole are formed in the single-communication four-hole closed-loop superconducting sheet, and slits are formed between the first circular hole and the fourth circular hole, between the second circular hole and the fourth circular hole and between the third circular hole and the fourth circular hole; the three solenoids are sleeved with the single-communication four-hole closed-loop superconducting piece through the first round hole, the second round hole and the third round hole respectively. And the plurality of single-communication four-hole closed-loop superconducting sheet stacking units are uniformly distributed in the circumferential direction by taking the fourth round hole as the center. The device is composed of a full superconducting loop, is simple in structure, does not need welding, a power supply and a current lead, can stably output a required strong magnetic field, and can also be applied to occasions such as medium and large superconducting magnets.