Circuit device and control method

Abstract

To provide a circuit device capable of controlling an oscillating state of an oscillator while reducing the number of output channels of a phase lock signal.SOLUTION: A circuit device comprises: multiple parametric oscillators; a magnetic field generation part provided for each parametric oscillator; a coupler provided for each parametric oscillator; a signal output part for outputting a phase lock signal incident to the parametric oscillator via the coupler and outputting a pump signal incident to the magnetic field generation part; and a control part for controlling the signal output part. The parametric oscillator comprises a variable element. The magnetic field generation part applies the magnetic field to the variable element. The signal output part comprises output channels of the phase lock signal fewer than the number of the parametric oscillators. The control part controls a phase difference between the phase lock signal and the pump signal.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present disclosure relates to a circuit device and a control method.

Background Art

[0002] A Josephson parametric oscillator (JPO) is one of the superconducting qubits used in quantum computing. Patent Document 1 discloses a quantum computer including a configuration in which a plurality of JPOs are coupled. When two coherent states of a JPO are adopted as operation bits (0 and 1 respectively, hereinafter referred to as qubits), the JPO can be controlled by inputting two types of high-frequency signals. The first is a pump signal. When an alternating magnetic field based on the pump signal is input to the SQUID (superconducting quantum interference device) loop circuit provided in the JPO, the JPO oscillates and operates as a qubit. The second is a phase-locked signal. When a high-frequency signal (phase-locked signal) is input to the JPO via a coupler, the generation probabilities of the 0 state and the 1 state can be controlled (Non-Patent Document 1).

[0003] Non-Patent Document 1 discloses a technique for controlling a JPO by inputting the above-described two types of high-frequency signals. According to the technique disclosed in Non-Patent Document 1, the number of JPOs constituting the arithmetic device is the same as the number of output channels for outputting the phase-locked signal.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Non-Patent Documents

[0005]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] When considering scaling up a quantum computer with multiple JPOs as in Patent Document 1, if a phase-locking signal is individually input to each JPO, as the number of JPOs increases, the number of output channels increases, and the device may become larger. Even outside of quantum computers with JPOs, when considering scaling up a device with multiple oscillators, if a phase-locking signal is individually input to each oscillator, as the number of oscillators increases, the number of output channels increases, and the device may become larger. Therefore, one of the objectives is to provide a technique that enables control of the oscillation state of an oscillator while reducing the number of output channels of the phase-locking signal.

Means for Solving the Problems

[0007] According to one aspect of the present disclosure, a circuit device includes a plurality of parametric oscillators, a magnetic field generation unit provided for each of the parametric oscillators, a coupler provided for each of the parametric oscillators, a phase-locked signal incident on the parametric oscillator via the coupler, a pump signal incident on the magnetic field generation unit, a signal output unit that outputs the signals, and a control unit that controls the signal output unit. The parametric oscillator includes a variable element, the magnetic field generation unit applies a magnetic field to the variable element, the signal output unit includes output channels for the phase-locked signal that are fewer than the number of parametric oscillators, and the control unit controls the phase difference between the phase-locked signal and the pump signal.

[0008] According to one aspect of the present disclosure, a control method is for a circuit device that includes a plurality of parametric oscillators, a magnetic field generation unit provided for each of the parametric oscillators, a coupler provided for each of the parametric oscillators, a phase-locked signal incident on the parametric oscillator via the coupler, a pump signal incident on the magnetic field generation unit, and a signal output unit that outputs the signals. The parametric oscillator includes a variable element, the magnetic field generation unit applies a magnetic field to the variable element, and the signal output unit includes output channels for the phase-locked signal that are fewer than the number of parametric oscillators. The method controls the phase difference between the phase-locked signal and the pump signal.

Advantages of the Invention

[0009] According to the present disclosure, it is possible to control the oscillation state of an oscillator while reducing the number of output channels of the phase-locked signal.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0011] In the present disclosure, a parametric oscillator is an oscillator having a variable element, and the oscillator is parametrically excited by periodically changing the circuit parameters of the variable element by an external action. The circuit parameters of the variable element are, for example, the inductance of an inductor. In this case, an inductor capable of changing the inductance is used. The external action is, for example, a magnetic field. Hereinafter, an example using a Josephson parametric oscillator as the parametric oscillator is shown. However, the point of controlling the oscillation state of the oscillator (for example, the state of the oscillation phase) is the same even when using other oscillators. When used as a quantum bit, the point of representing two states depending on the state of the oscillation phase is the same even when using other oscillators.

[0012] Hereinafter, the control device of the JPO and the superconducting quantum circuit device according to each embodiment of the present disclosure will be described with reference to the drawings. Here, the superconducting quantum circuit device is a form of the circuit device in the present application, and is a circuit device that utilizes superconductivity and quantum phenomena. In the drawings used in the following description, the configuration of parts not related to the present disclosure may be omitted and may not be illustrated. In all the drawings, the same or corresponding configurations are denoted by the same reference numerals, and common descriptions may be omitted.

[0013] <First Embodiment> (Configuration) FIG. 1 is a first diagram showing an example of a superconducting quantum circuit device according to an embodiment. As shown in FIG. 1, the superconducting quantum circuit device 100 includes a control unit 10, a phase-locked signal output unit 11, a distributor 12, N couplers 13-1 to 13-N, N JPOs 14-1 to 14-N, a pump signal output unit 15, and N magnetic field generation units 16-1 to 16-N.

[0014] The phase-locked signal output unit 11 includes a signal output unit 111. The signal output unit 111 is one output channel. The phase-locked signal output unit 11 is constituted by, for example, an arbitrary waveform generator, an IQ mixer, a digital-to-analog conversion circuit, etc., but is not limited thereto. The phase-locked signal output unit 11 outputs a phase-locked signal having a waveform according to the following formula (2) from the signal output unit 111 based on an instruction from the control unit 10. Here, t is time, V li is the voltage amplitude, f li is the frequency, θ´ li is the phase, g li (t) indicates the envelope of the pulse. For example, f li is the same frequency as the resonance frequency of JPO 14-i. Examples of the pulse envelope g pi (t) include, but are not limited to, a Gaussian function, a rectangular function, and a trapezoidal function.

[0015]

Equation

[0016] The distributor 12 connects the signal output unit 111 and the couplers 13-1 to 13-N. The distributor 12 is constituted by, for example, a transmission line, a splitter, a filter, etc., but is not limited thereto.

[0017] The coupler 13-i (i = 1 to N) transmits the phase-locked signal from the distributor 12 to the JPO 14-i. The couplers 13-1 to 13-N are constituted by using, for example, capacitors, and transmit the phase-locked signal from the distributor 12 to the JPO 14-i (i = 1 to N) by a resonator, capacitive coupling, inductive coupling, etc., but are not limited thereto.

[0018] The distributor 12 and the combiners 13-1 to 13-N are configured such that a signal proportional to P li (t) is transmitted to the i-th JPO. li The signal proportional to P li (t) represents, for example, a signal obtained by attenuating or amplifying the voltage of P li (t). For example, the distributor 12 may be constituted by a transmission line, and a filter or the like that allows only the signal of the frequency incident on the first JPO 14-1 to pass through may be provided at the connection portion with the combiner 13-1, and a filter or the like that allows only the signal of the frequency incident on the i-th JPO 14-i to pass through may be provided at the connection portion of the combiner 13-i. As another configuration example, P lj in addition to P l (t), different signals, for example P l (t) (j ≠ i and 1 ≤ j ≤ N) may be configured to be transmitted to the i-th JPO 14-i. For example, the distributor 12 may be constituted by a transmission line and may be configured without providing a filter or the like. The resonance frequencies of JPOs 14-1 to 14-N are different from each other, and from the phase-locked signal output unit 11, a signal P li (t) in which the resonance frequencies of JPOs 14-1 to 14-N are superimposed is transmitted. When no filter or the like is provided in the distributor 12, P lj (t) is incident on JPOs 14-1 to 14-N. In this case, if the signal P lj (t) corresponding to the resonance oscillation frequency of JPO 14-i is included, even if a different signal P

[0019] (t) is transmitted to JPO 14-i, it does not significantly affect the oscillation of JPO 14-i. Therefore, it can be configured such that P (t) (j ≠ i and 1 ≤ j ≤ N) is transmitted to JPO 14-i.JPO14-1 to JPO14-N are Josephson parametric oscillators. One qubit is represented by one JPO14-i. JPO14-1 includes a capacitor 141-1 and a loop circuit 142-1. The loop circuit 142-1 is formed by connecting two or more Josephson junctions in a ring, and can also be called a SQUID. Here, a Josephson junction refers to an element having a structure in which a thin insulating film is sandwiched between a first superconductor and a second superconductor. The loop circuit 142 is a kind of variable element as described later and acts as an equivalent inductor. Therefore, JPO14-1 resonates at a frequency specified by its equivalent inductance and the capacitance of the capacitor, and JPO14-1 oscillates by a pump signal described later. The same applies to the other JPO14-2 to JPO14-N. A phase-locked signal having the same frequency as the resonance frequency of JPO14-i is configured to be incident on JPO14-i. Further, a pump signal having a frequency, for example, about twice the resonance frequency of JPO14-i is configured to be incident on the magnetic field generation unit 16-i corresponding to JPO14-i.

[0020] The pump signal output unit 15 includes signal output units 151-1 to 151-N. The signal output units 151-1 to 151-N are N output channels. The pump signal output unit 15 is constituted by, for example, an arbitrary waveform generator, an IQ mixer, a digital-to-analog conversion circuit, etc., but is not limited thereto. The signal output unit 151-1 outputs a pump signal to the magnetic field generation unit 16-1, generates an alternating magnetic field, and applies the alternating magnetic field to the loop circuit 142-1. The same applies to the signal output units 151-2 to 151-N. The pump signal output unit 15 outputs a pump signal having a waveform according to the following formula (3) from the i-th signal output unit 151-i based on an instruction from the control unit 10. P pi (t)=V pi sin(2πf pi t+θ´ pi )·g pi (t)···(3) Here, t is time, V pi is the voltage amplitude, f pi is the frequency, θ´ piis the phase, g pi (t) represents the envelope of the pulse. For example, f pi is a frequency that is, for example, approximately twice the resonance frequency of JPO14-i. Examples of the envelope g pi (t) include, but are not limited to, a Gaussian function, a rectangular function, and a trapezoidal function.

[0021] At this time, the path delay from the pump signal output unit 15 to the magnetic field generation units 16-1 to 16-N is considered. That is, the phase of the signal incident on JPO14-1 to JPO14-N is θ pi , the path delay is δ pi When defined as, θ' in Equation (3) pi is calculated as shown in the following Equation (4). θ' pi = θ pi - δ pi ···(4)

[0022] The magnetic field generation unit 16-1 and the loop circuit 142-1 are magnetically coupled via mutual inductance. The magnetic field generation unit 16-1 is a circuit that generates an alternating magnetic field by the current flowing through the magnetic field generation unit 16-1 and applies the alternating magnetic field to the loop circuit 142-1. The equivalent inductance of the loop circuit 142-1 changes according to the magnitude of the magnetic field applied to the loop circuit 142-1. That is, the loop circuit 142-1 is a variable element. Thereby, JPO14-1 can be parametrically oscillated by the alternating magnetic field. In addition to the alternating current, a direct current may be superimposed on the magnetic field generation unit 16-1, and the resonance frequency or oscillation frequency of JPO14-1 can be controlled by the magnitude of the direct current. The same applies to the magnetic field generation units 16-2 to 16-N.

[0023] The control unit 10 controls the phase lock signal output unit 11 and the pump signal output unit 15 to output high-frequency signals having predetermined frequencies and phases to each. As described above, when controlling the quantum bit, an operation of the phase difference between the two signals is required. Taking a certain time as a reference point, the phase of the pump signal incident on the JPO is θ p , and the phase of the phase lock signal is θ lThen, by operating the phase difference Δθ defined by the following equation (1), the generation probabilities of the 0 state and the 1 state of the quantum bit can be controlled. Δθ = θ l -(θ p / 2) ···(1) The control unit 10 operates the phase difference Δθ defined by the above equation (1) by causing each of the phase lock signal output unit 11 and the pump signal output unit 15 to output a desired signal, and controls the generation probabilities of the 0 state and the 1 state of the quantum bit of JPO14-i. Specifically, the control unit 10 calculates the phase θ' of the above equation (2) according to the following equations (5) and (6). li to calculate. θ' li = θ li - δ li ···(5) θ li =(θ pi / 2)+Δθ i ···(6) Here, θ li is the phase of the signal incident on the i-th JPO14-i, δ li is the path delay from the phase lock signal output unit 11 to the i-th JPO14-i, and Δθ i represents a parameter that can be operated by the control unit 10 to an arbitrary value.

[0024] In the superconducting quantum circuit device 100 of FIG. 1, a pump signal having a frequency f pi and a phase θ pi is incident on the magnetic field generation unit 16-i corresponding to the i-th JPO14-i. Also, a phase lock signal having a frequency f li and a phase θ li is incident on the i-th JPO14-i. Therefore, the phase difference Δθ between the two signals incident on the i-th JPO14-i is Δθ of the following equation i and its value can be arbitrarily operated by the control unit 10.

[0025] Δθ i = θ li -(θ pi / 2) ···(1´)

[0026] Next, as described with reference to FIG. 2, Δθ i corresponds to the qubit state (probability of occurrence of the 0 state and the 1 state) of JPO14-i. In other words, by operating Δθ i to a desired value, the probabilities of occurrence of the 0 state and the 1 state in the i-th JPO14-i can be controlled. The control unit 10 controls the phase difference Δθ i between the phase-locked signal and the pump signal according to equations (5), (6), and (1´) to control the qubit state of JPO14-i.

[0027] FIG. 2 shows an example of the relationship between Δθ i and the probabilities of occurrence of the 0 state and the 1 state. The vertical axis in FIG. 2 shows the probability of occurrence of the 1 state, and the horizontal axis shows the phase difference Δθ i between the phase-locked signal and the pump signal. For example, when it is desired that the probability of occurrence of 1 be y, the control unit 10 controls the phases of the phase-locked signal incident on JPO14-i and the pump signal incident on the magnetic field generation unit 16-i so that Δθ i becomes x. Thereby, the probability of occurrence of the 1 state in JPO14-i can be controlled to y, and the probability of occurrence of the 0 state in JPO14-i can be controlled to 1 - y.

[0028] When an alternating magnetic field approximately twice the resonance frequency of JPO14-i is applied to the magnetic field generation unit 16-i and a phase-locked signal having the same frequency as the resonance frequency is incident on JPO14-i, JPO14-i oscillates. In a quantum computer including the superconducting quantum circuit device 100, the probabilities of occurrence of the 0 state and the 1 state are read from the oscillation state of JPO14-i to execute a calculation. For example, when the control unit 10 controls so that Δθ i = x, in the quantum computer, the probability of occurrence of the 0 state = 1 - y and the probability of occurrence of the 1 state = y are read.

[0029] For comparison, a configuration example of a general superconducting quantum circuit device including N JPOs is shown in FIG. 6. In the superconducting quantum circuit device 100' illustrated in FIG. 6, the phase-locked signal output unit 11' includes N output channels, signal output units 111-1 to 111-N. The signal output unit 111-1 is connected to the coupler 13-1, and the signal output unit 111-1 is configured to incident the phase-locked signal P l1 (t) having the frequency and phase for the first JPO 14-1 to the JPO 14-1. The same applies to the signal output units 111-2 to 111-N.

[0030] In contrast, in the superconducting quantum circuit device 100 according to the present embodiment illustrated in FIG. 1, the number of output channels of the phase-locked signal output unit 11 is reduced to 1. Further, the phase difference Δθ i between the phase-locked signal incident on the JPO 14-i (i = 1 to N) and the pump signal incident on the magnetic field generation unit 16-i is operable.

[0031] (Effect) As described above, according to the superconducting quantum circuit device 100 according to the first embodiment, it is possible to reduce the number of output channels of the phase-locked signal and control the generation probabilities of the 0 state and 1 state of the JPO.

[0032] In the example of FIG. 1, the number of output channels of the phase-locked signal output unit 11 is reduced from N to 1, but the embodiment is not limited thereto. For example, the number of output channels is reduced to 2, and from the first output channel, the phase-locked signal defined by Equation (2) is output to the JPOs 14-1 to 14-n (1 ≤ n < N), and the same phase-locked signal defined by Equation (2) is output to the remaining JPOs 14-n+1 to 14-N. Similarly, the number of output channels of the phase-locked signal may be reduced from N to 3. By making the number of output channels of the phase-locked signal less than the number of JPOs, it is possible to suppress the increase in the size and cost of the device.

[0033] <Second Embodiment> (Configuration) FIG. 3 is a second diagram showing an example of a superconducting quantum circuit device according to an embodiment. As shown in FIG. 3, the superconducting quantum circuit device 100A includes a control unit 10A, a phase-locked signal output unit 11, a distributor 12, N couplers 13-1 to 13-N, N JPOs 14-1 to 14-N, a pump signal output unit 15A, N magnetic field generation units 16-1 to 16-N, and a distributor 17.

[0034] Compared with the first embodiment, the number of output channels of the pump signal is reduced from N to 1, and the pump signal is incident on the magnetic field generation units 16-1 to 16-N via the distributor 17 from one output channel, which is different.

[0035] The pump signal output unit 15A includes a signal output unit 151A which is one output channel. The pump signal output unit 15A is composed of, for example, an arbitrary waveform generator, an IQ mixer, a digital-to-analog conversion circuit, etc., but is not limited thereto. The pump signal output unit 15A outputs a pump signal having a waveform according to the following formula (7) from the signal output unit 151A based on an instruction from the control unit 10. For P in the right side of formula (7) Pi (t), it is as shown in the above formula (3).

[0036]

Equation

[0037] The distributor 17 connects the signal output unit 151A and the magnetic field generation units 16-1 to 16-N. The distributor 17 is composed of, for example, a transmission line, a splitter, a filter, etc., but is not limited thereto.

[0038] The distributor 17 is configured such that a signal proportional to P pi (t) is transmitted to the i-th magnetic field generation unit 16-i. The signal proportional to P pi (t) means, for example, P piRepresents a signal whose voltage of (t) has been attenuated or amplified. For example, the distributor 17 may be configured by a transmission line, and further, a filter or the like that passes only the signal of the frequency incident on the first magnetic field generation unit 16-1 may be provided at the connection part with the magnetic field generation unit 16-1, and a filter or the like that passes only the signal of the frequency incident on the i-th magnetic field generation unit 16-i may be provided at the connection part of the magnetic field generation unit 16-i. It may be configured in such a way. As another configuration example, in addition to P pi (t), different signals, for example, P pj (t) (j≠i and 1≦j≦N) may be configured to be transmitted to the i-th magnetic field generation unit 16-i. The reason is the same as in the case of the phase-locked signal.

[0039] The control unit 10A instructs the phase-locked signal output unit 11 to output a phase-locked signal having a waveform according to Equation (2), and instructs the pump signal output unit 15A to output a pump signal having a waveform according to Equation (7). Also in this case, the control unit 10A, based on the above-described Equations (5), (6), and (1´), controls the phase difference Δθ i to control the quantum bit state of JPO14-i (i = 1 to N) by operating.

[0040] (Effect) As described above, according to the superconducting quantum circuit device 100A according to the second embodiment, in addition to the effects obtained by the superconducting quantum circuit device 100 illustrated in FIG. 1, it is possible to reduce the number of output channels of the pump signal.

[0041] In the example of FIG. 3, the number of output channels of the pump signal output unit 15A is reduced from N to 1, but the embodiment is not limited to this. For example, the number of output channels of the pump signal output unit 15A may be reduced to 2, and from the first output channel, a pump signal defined by Equation (7) is output to the magnetic field generation units 16-1 to 16-n (1≦n<N), and the same pump signal defined by Equation (7) is output to the remaining magnetic field generation units 16-n+1 to 16-N. Similarly, the number of output channels of the pump signal may be reduced to 3. By making the number of output channels of the phase-locked signal and the pump signal less than the number of JPQs, it is possible to suppress the increase in the size and cost of the device.

[0042] <Third Embodiment> (Configuration) FIG. 4 is a third diagram showing an example of a superconducting quantum circuit device according to an embodiment. As shown in FIG. 4, the superconducting quantum circuit device 100B includes a control unit 10B, an output unit 18 for a phase-locked signal and a pump signal, a distributor 19, N couplers 13-1 to 13-N, N JPOs 14-1 to 14-N, and N magnetic field generation units 16-1 to 16-N.

[0043] Compared with the first and second embodiments, the points of difference are that the pump signal and the phase-locked signal are output from a common single output channel, the phase-locked signal is incident on the N JPOs via a common single distributor 19 and couplers 13-1 to 13-N, and the pump signal is incident on the N magnetic field generation units 16-1 to 16-N via the distributor 19.

[0044] The output unit 18 for the phase-locked signal and the pump signal includes a signal output unit 181 which is a single output channel. The output unit 18 for the phase-locked signal and the pump signal is constituted by, for example, an arbitrary waveform generator, an IQ mixer, a digital-to-analog conversion circuit, etc., but is not limited thereto. The output unit 18 for the phase-locked signal and the pump signal outputs a pump signal having a waveform according to the following formula (8) from the signal output unit 181 based on an instruction from the control unit 10B. P on the right side of formula (8) li (t) is the above-mentioned formula (2), P Pi (t) is as shown by the above-mentioned formula (3).

[0045] [Number]

[0046] The distributor 19 connects the signal output unit 181 and the magnetic field generation units 16-1 to 16-N, and connects the signal output unit 181 and the couplers 13-1 to 13-N. The distributor 19 is constituted by, for example, a transmission line, a splitter, a filter, etc., but is not limited thereto.

[0047] The distributor 19 and the coupler 13-i are configured such that a signal proportional to P li (t) is transmitted to the i-th JPO 14-i. Alternatively, in addition to P li (t), different signals, P lj (t) (j ≠ i and 1 ≤ j ≤ N) and / or P pk (t) (1 ≤ k ≤ N) may be configured to be transmitted to the JPO 14-i. In addition, the distributor 19 is configured such that a signal proportional to P pi (t) is transmitted to the i-th magnetic field generation unit 16-i. Alternatively, in addition to P pi (t), different signals, P pj (t) (j ≠ i and 1 ≤ j ≤ N) and / or P lk (t) (1 ≤ k ≤ N) may be configured to be transmitted to the magnetic field generation unit 16-i. For example, the distributor 19 may be constituted by a transmission line, or a filter or the like that passes only signals of the frequency incident on the JPO 14-i may be provided at the connection part with the coupler 13-i. Also, a filter or the like that passes only signals of the frequency incident on the magnetic field generation unit 16-i may be provided at the connection part of the distributor 19 with the magnetic field generation unit 16-i.

[0048] The control unit 10B instructs the output unit 18 of the phase-locked signal and the pump signal to output a signal having a waveform according to the formula (8). Also in this case, the control unit 10A controls the quantum bit state of the JPO 14-i (i = 1 to N) by operating the phase difference Δθ i as described above based on the formulas (5), (6), and (1´).

[0049] (Effect) As described above, according to the superconducting quantum circuit device 100B according to the third embodiment, in addition to the effects obtained by the superconducting quantum circuit device 100 illustrated in FIG. 1 and the superconducting quantum circuit device 100A illustrated in FIG. 3, the number of signal output channels can be further reduced.

[0050] In the example of FIG. 4, the number of output channels of the phase-locked signal and the pump signal in the output unit 18 is set to 1, but it may be 2 or 3, for example. By making the number of output channels less than the number of JPOs, it is possible to suppress the increase in the size and cost of the apparatus.

[0051] (Fourth Embodiment) FIG. 5 is a fourth diagram showing an example of a superconducting quantum circuit device according to the embodiment. The superconducting quantum circuit device 100C includes a plurality of Josephson parametric oscillators (JPOs) 14-1 to 14-N, magnetic field generation units 16-1 to 16-N provided for each of the Josephson parametric oscillators 14-1 to 14-N, couplers 13-1 to 13-N provided for each of the Josephson parametric oscillators 14-1 to 14-N, a signal output unit 18C that outputs a phase-locked signal incident via the couplers 13-1 to 13-N corresponding to the Josephson parametric oscillators 14-1 to 14-N and a pump signal incident on the magnetic field generation units 16-1 to 16-N, and a control unit 10C that controls the signal output unit 18C. Each of the Josephson parametric oscillators 14-1 to 14-N includes a loop circuit 142-1 to 142-N. Each of the magnetic field generation units 16-1 to 16-N applies a magnetic field to the loop circuits 142-1 to 142-N. The signal output unit 18C includes output channels 181C of the phase-locked signal that are fewer in number than the number of the Josephson parametric oscillators 14-1 to 14-N. The control unit 10C controls the phase difference between the phase-locked signal and the pump signal. Thereby, for example, the states of the quantum bits of the Josephson parametric oscillators 14-1 to 14-N are controlled.

[0052] As described above in detail with reference to the drawings, although one embodiment of the present disclosure has been described, the specific configuration is not limited to the above, and various design changes and the like can be made without departing from the gist of the invention. Also, one aspect of the present disclosure can be variously modified within the scope shown in the claims, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present disclosure. Further, configurations in which elements described in the above embodiments and modification examples and having the same effects are replaced with each other are also included. And each embodiment can be combined with other embodiments as appropriate. Also, as exemplified in Patent Document 1, a circuit or wiring for coupling Josephson parametric oscillators to each other may be separately provided for quantum computing. Further, although the state of the qubit has been described as the states of "0" and "1" above, the state of the qubit can also be considered as the states of "+1" and "-1", and the effects of the present embodiment are the same in that case. Also, although an example in which the oscillation state of the oscillator is used as the state of the qubit has been described above, the oscillator and its oscillation state may be used for other purposes. Other purposes include, for example, reading the state of a qubit, amplifying a signal, and causing qubits to interact with each other.

[0053] Some or all of the above embodiments may be described as follows in the appended claims, but are not limited thereto.

[0054] (Appendix 1) A circuit device comprising: a plurality of parametric oscillators; a magnetic field generation unit provided for each of the parametric oscillators; a coupler provided for each of the parametric oscillators; a phase-locked signal incident on the parametric oscillator via the coupler; a pump signal incident on the magnetic field generation unit; a signal output unit that outputs the phase-locked signal and the pump signal; and a control unit that controls the signal output unit, wherein the parametric oscillator includes a variable element, the magnetic field generation unit applies a magnetic field to the variable element, the signal output unit includes an output channel for the phase-locked signal that is fewer than the number of the parametric oscillators, and the control unit controls the phase difference between the phase-locked signal and the pump signal.

[0055] (Appendix 2) The signal output unit outputs the phase-locked signal in which signals of different frequencies determined for each of the parametric oscillators are superimposed, and includes one output channel for outputting the superimposed phase-locked signal, and is the circuit device according to Appendix 1.

[0056] (Appendix 3) The circuit device according to Appendix 1 or Appendix 2, wherein each of the output channel of the phase-locked signal and the coupler is connected by a transmission line.

[0057] (Appendix 4) The circuit device according to Appendix 1 or Appendix 2, wherein each of the output channel of the phase-locked signal and the coupler is connected by a transmission line, and a filter for passing the phase-locked signal of a predetermined frequency corresponding to the frequency determined for the parametric oscillator corresponding to the coupler is provided at a connection portion between the transmission line and the coupler.

[0058] (Appendix 5) The circuit device according to any one of Appendix 1 to Appendix 4, wherein the signal output unit includes output channels of the pump signals that are fewer than the number of the parametric oscillators.

[0059] (Appendix 6) The signal output unit outputs the pump signal in which signals of different frequencies determined for each of the parametric oscillators are superimposed, and includes one output channel for outputting the superimposed pump signal, and is the circuit device according to any one of Appendix 1 to Appendix 5.

[0060] (Appendix 7) The circuit device according to Appendix 6, wherein each of the output channel of the pump signal and the magnetic field generation unit is connected by a transmission line.

[0061] (Appendix 8) The output channel of the pump signal and each of the magnetic field generation units are connected by a transmission line, and a filter that passes the pump signal of a predetermined frequency corresponding to the frequency determined for the parametric oscillator corresponding to the magnetic field generation unit is provided at the connection portion between the transmission line and the magnetic field generation unit. The circuit device according to Supplementary Note 6.

[0062] (Supplementary Note 9) The signal output unit outputs the phase-locked signals of different frequencies determined for each of the parametric oscillators and a signal obtained by superimposing the phase-locked signals, and includes one output channel that outputs the superimposed signal. The circuit device according to Supplementary Note 1.

[0063] (Supplementary Note 10) The output channel and each of the couplers are connected by a transmission line. The circuit device according to Supplementary Note 9.

[0064] (Supplementary Note 11) The output channel and each of the couplers are connected by a transmission line, and a filter that passes the signal of the frequency determined for the parametric oscillator corresponding to the coupler is provided at the connection portion between the transmission line and the coupler. The circuit device according to Supplementary Note 9.

[0065] (Supplementary Note 12) The output channel and each of the magnetic field generation units are connected by a transmission line. The circuit device according to any one of Supplementary Notes 9 to 11.

[0066] (Supplementary Note 13) The output channel and each of the magnetic field generation units are connected by a transmission line, and a filter that passes the signal of the frequency determined for the parametric oscillator corresponding to the magnetic field generation unit is provided at the connection portion between the transmission line and the magnetic field generation unit. The circuit device according to any one of Supplementary Notes 9 to 11.

[0067] (Supplementary Note 14) The parametric oscillator is a qubit, and the state of the qubit is controlled by the phase difference, the circuit device according to any one of Appendices 1 to 13.

[0068] (Appendix 15) A circuit device including a plurality of parametric oscillators, a magnetic field generation unit provided for each of the parametric oscillators, a coupler provided for each of the parametric oscillators, and a signal output unit that outputs a phase-locked signal incident on the parametric oscillator via the coupler and a pump signal incident on the magnetic field generation unit, wherein the parametric oscillator includes a variable element, the magnetic field generation unit applies a magnetic field to the variable element, and the signal output unit includes an output channel for the phase-locked signal that is smaller in number than the number of the parametric oscillators. A control method for controlling the phase difference between the phase-locked signal and the pump signal.

[0069] (Appendix 16) The parametric oscillator is a qubit, and the state of the qubit is controlled by the phase difference, which is the control method according to Appendix 15.

[0070] (Appendix 17) In the circuit device, based on data associating the phase difference with the generation probabilities of the 0 state and the 1 state of the qubits of the parametric oscillator and the desired generation probabilities, the control method according to Appendix 15 or Appendix 16 for controlling the phase difference.

[0071] For the circuit device in the control methods of Appendices 15 to 17, the aspects of Appendices 2 to 13 can be applied.

[0072] The superconducting quantum circuit devices 100, 100A, 100B, and 100C of the embodiment are examples of circuit devices. JPO14-1 to 14-N are examples of parametric oscillators. The loop circuits 142-1 to 142-N are examples of variable elements.

Description of Reference Numerals

[0073] 100, 100A, 100B, 100C ··· Superconducting quantum circuit device 10, 10A, 10B, 10C ··· Control unit 11 ··· Phase-locked signal output unit 12, 17, 19 ··· Distributor 13-1 to 13-N ··· Coupler 14-1 to 14-N ··· JPO 141-1 to 141-N ··· Capacitor 142-1 to 142-N ··· Loop circuit 15, 15A ··· Pump signal output unit 16-1 to 16-N ··· Magnetic field generation unit 18 ··· Output unit of phase-locked signal and pump signal 18C ··· Signal output unit

Claims

1. A plurality of parametric oscillators, a magnetic field generation unit provided for each of the parametric oscillators, a coupler provided for each of the parametric oscillators, a signal output unit that outputs a phase-locked signal incident on the parametric oscillator via the coupler and a pump signal incident on the magnetic field generation unit, a control unit that controls the signal output unit, comprising the parametric oscillator includes a variable element, the magnetic field generation unit applies a magnetic field to the variable element, the signal output unit includes output channels of the phase-locked signal that are fewer than the number of the parametric oscillators, the control unit controls a phase difference between the phase-locked signal and the pump signal, a circuit device.

2. the signal output unit outputs the phase-locked signal in which signals having different frequencies determined for each of the parametric oscillators are superimposed, the signal output unit includes one output channel that outputs the superimposed phase-locked signal, the circuit device according to claim 1.

3. each of the output channels of the phase-locked signal and the coupler are connected by a transmission line, the circuit device according to claim 1 or claim 2.

4. each of the output channels of the phase-locked signal and the coupler are connected by a transmission line, and a filter that passes the phase-locked signal having a predetermined frequency corresponding to the frequency determined for the parametric oscillator corresponding to the coupler is provided at a connection portion between the transmission line and the coupler, the circuit device according to claim 1 or claim 2.

5. The signal output unit includes output channels for the pump signal that are fewer in number than the number of parametric oscillators. The circuit device according to claim 1 or claim 2.

6. The signal output unit outputs the pump signal in which signals of different frequencies determined for each parametric oscillator are superimposed. The pump signal output unit includes one output channel for outputting the superimposed pump signal. The circuit device according to claim 1 or claim 2.

7. Each of the output channels of the pump signal and the magnetic field generation unit is connected by a transmission line, or each of the output channels of the pump signal and the magnetic field generation unit is connected by a transmission line, and a filter for passing the pump signal of a predetermined frequency corresponding to the frequency determined for the parametric oscillator corresponding to the magnetic field generation unit is provided at the connection portion between the transmission line and the magnetic field generation unit. The circuit device according to claim 6.

8. The signal output unit outputs the phase-locked signal of different frequencies determined for each parametric oscillator and the signal in which the phase-locked signals are superimposed. The output unit for outputting the superimposed signal includes one output channel. The circuit device according to claim 1.

9. The parametric oscillator is a quantum bit, and the state of the quantum bit is controlled by the phase difference. The circuit device according to claim 1.

10. A plurality of parametric oscillators, A magnetic field generation unit provided for each parametric oscillator, A coupler provided for each parametric oscillator, A signal output unit that outputs a phase-locked signal incident on the parametric oscillator via the coupler and a pump signal incident on the magnetic field generation unit. comprising the parametric oscillator includes a variable element, the magnetic field generating unit applies a magnetic field to the variable element, in a circuit device in which the signal output unit includes output channels for the phase-locked signals that are fewer than the number of the parametric oscillators, controlling a phase difference between the phase-locked signal and the pump signal, control method.

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