WO2018159832A1 - Modulation circuit, control circuit, information processing device, and integration method - Google Patents

Modulation circuit, control circuit, information processing device, and integration method Download PDF

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WO2018159832A1
WO2018159832A1 PCT/JP2018/008105 JP2018008105W WO2018159832A1 WO 2018159832 A1 WO2018159832 A1 WO 2018159832A1 JP 2018008105 W JP2018008105 W JP 2018008105W WO 2018159832 A1 WO2018159832 A1 WO 2018159832A1
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circuit
resonance circuit
contact
resonance
phase
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PCT/JP2018/008105
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French (fr)
Japanese (ja)
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泰信 中村
ピエールマリー ビランジョン
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国立研究開発法人科学技術振興機構
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Publication of WO2018159832A1 publication Critical patent/WO2018159832A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/32—Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26
    • H04L27/34—Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems
    • H04L27/36—Modulator circuits; Transmitter circuits

Definitions

  • the interaction between the two superconducting qubits may be strong from the viewpoint of shortening the time or improving the accuracy of the two-qubit gate operation.
  • the state in which the two resonance circuits are electrically coupled to each other means a state in which a current flows from one resonance circuit to the other resonance circuit, and the two resonance circuits are connected to each other. Does not mean that they are physically connected by.
  • the state in which the two resonance circuits are not electrically coupled is a state in which current flows from one resonance circuit to the other resonance circuit. This means that the two resonance circuits are not physically connected to each other by wiring.
  • the coupling state is changed to the first resonance based on the first phase, the second phase, the third phase, and the fourth phase.
  • a configuration in which the circuit and the second resonance circuit are not coupled to each other and the state in which the first resonance circuit and the second resonance circuit are coupled may be used.
  • each of the first resonance circuit and the second resonance circuit is supplied from a power source that supplies an AC voltage to each of the first resonance circuit and the second resonance circuit.
  • the coupled state is changed to a state in which the first resonant circuit and the second resonant circuit are coupled, and the first resonant circuit and the first resonant circuit are changed by the power source.
  • the coupling state is changed to a state where the first resonance circuit and the second resonance circuit are not coupled. Also good.
  • the modulation circuit includes a fourth Josephson junction element having a ⁇ junction located between the fourth contact and the first contact.
  • At least one of the first resonance circuit RC1 and the second resonance circuit RC2 is a qubit circuit including a Josephson junction element, that is, a qubit circuit in which a superconducting qubit is configured by a Josephson junction element.
  • a qubit circuit including a Josephson junction element that is, a qubit circuit in which a superconducting qubit is configured by a Josephson junction element.
  • the power source PW is a power source that supplies an AC voltage having a predetermined frequency to each of the first resonance circuit RC1 and the second resonance circuit RC2.
  • the predetermined frequency is a resonance frequency of at least one of the first resonance circuit RC1 and the second resonance circuit RC2, and in this example, is a frequency included in a microwave frequency band.
  • the predetermined frequency may be a frequency included in another frequency band instead of the frequency included in the microwave frequency band. Below, the case where the said frequency is the resonant frequency of 1st resonant circuit RC1 is demonstrated as an example.
  • phase phi W, and the phase phi q, the phase phi r, each of the phase phi Z, the first phase phi 1, a second phase phi 2, a third phase phi 3, and the fourth phase phi 4 Represents each of the four linearly independent variables (degrees of freedom) that can be created by each linear combination.
  • the phase ⁇ W is a degree of freedom unrelated to the operation of the control circuit 1 according to the present embodiment, and thus does not appear in the above equation (1).
  • ⁇ 0 represents the magnetic flux quantum h / (2e).
  • h represents the Planck constant
  • e represents the elementary charge.
  • Q q represents the charge stored in the first capacitor C1 and the second capacitor C2.
  • qr represents the electric charge stored in the 3rd capacitor C3 and the 4th capacitor C4.
  • q Z is a charge stored in the modulation circuit MC in case the AC voltage by the power supply PW is supplied to each of the first resonant circuit RC1 and the second resonant circuit RC2. That is, the modulation circuit MC also behaves as a capacitor having a capacitance. This is because each of the first Josephson junction element J1 to the fourth Josephson junction element J4 has a capacitance. Note that a variable with “ ⁇ ” immediately above in the above formula (1) indicates that the variable is an operator.
  • both the potential at the second contact P2 and the potential at the fourth contact P4 at a certain timing are 0, and the potential at the first contact P1 at the timing.
  • the potential at the third contact P3 must be able to have the same magnitude and opposite values.
  • both the potential at the second contact P2 and the potential at the fourth contact P4 are 0, and the potential at the first contact P1 and the potential at the third contact P3 at the timing are mutually equal. Is the same, and the sign is opposite.
  • “ ⁇ ” in the figure indicates a potential having the same magnitude as that of the potential indicated by “+” and having the opposite sign.
  • both the potential at the first contact P1 and the potential at the third contact P3 are 0, and the potential at the second contact P2 and the potential at the fourth contact P4 at the timing are mutually equal. Is the same, and the sign is opposite.
  • “+” In the figure indicates a positive potential
  • “ ⁇ ” in the figure indicates a potential having the same magnitude as that of the potential indicated by “+” and having the opposite sign.
  • “0” in the symbol indicates a potential of 0.
  • “1” in the figure indicates the first contact P1, “2” in the figure indicates the second contact P2, and “3” in the figure indicates the third contact P3.
  • “4” indicates the fourth contact P4.
  • both the potential at the potential and the third contact point P3 of the first contact point P1 at a certain timing becomes a positive value
  • the potential at the second contact point P2 at this timing the Both of the potentials at the four contacts P4 must be the same value as the positive value and can have opposite signs.
  • both the potential at the first contact P1 and the potential at the third contact P3 are positive values
  • both the potential at the second contact P2 and the potential at the fourth contact P4 are positive. The case where the value is the same as the value of and the value is the opposite sign is shown.
  • the potential at the first contact P1 and the potential at the third contact P3 at a certain timing are both 0 or large due to the structure of the control circuit 1 (the symmetry that the control circuit 1 has).
  • the values are the same and the values are opposite.
  • the potential of the second contact P2 and the potential of the fourth contact P4 at a certain timing are both 0 or the same in magnitude and positive / negative depending on the structure of the control circuit 1.
  • the opposite value. Therefore, the phase phi Z is always 0 when the, first resonant circuit RC1 and the second resonant circuit RC2, can not be electrically coupled.
  • each of the first resonance circuit RC1 and the second resonance circuit RC2 resonates according to the mutual resonance.
  • the above-mentioned sixth term (the above interaction term), in which the terms depending on the phase ⁇ r , the phase ⁇ q , and the phase ⁇ Z are not 0,
  • the virtual harmonic oscillator representing the resonance of the second resonance circuit RC2 has two quantum states (i.e.,
  • the strength of the interaction increases as the Josephson energy of each of the first Josephson junction element J1 to the fourth Josephson junction element J4 increases. For this reason, in the control circuit 1, the intensity of the interaction can be increased by increasing the Josephson energy.
  • the case where the switch of the power supply PW is on is a case where an AC voltage is supplied to each of the first resonance circuit RC1 and the second resonance circuit RC2 by the power supply PW.
  • the control circuit 1 (i.e., the modulation circuit MC) includes a first phase phi 1, a second phase phi 2, a third phase phi 3, based on the fourth phase phi 4, first resonant
  • the coupling state between the circuit RC1 and the second resonance circuit RC2 is changed. More specifically, the control circuit 1 includes a first phase phi 1, a second phase phi 2, a third phase phi 3, based on the fourth phase phi 4, and the first resonance circuit RC1 second
  • the state is changed to either a state where the resonance circuit RC2 is not coupled or a state where the first resonance circuit RC1 and the second resonance circuit RC2 are coupled. Thereby, the control circuit 1 can cut
  • control circuit 1 supplies an AC voltage to each of the first resonance circuit RC1 and the second resonance circuit RC2 by a power source PW that supplies an AC voltage to each of the first resonance circuit RC1 and the second resonance circuit RC2.
  • a power source PW that supplies an AC voltage to each of the first resonance circuit RC1 and the second resonance circuit RC2.
  • the coupling state between the first resonance circuit RC1 and the second resonance circuit RC2 is changed to a state in which the first resonance circuit RC1 and the second resonance circuit RC2 are coupled, and the first resonance is generated by the power supply PW.
  • the coupling state is changed to a state where the first resonance circuit RC1 and the second resonance circuit RC2 are not coupled.
  • the quantum state of the first resonance circuit RC1 (more specifically, the quantum state of the harmonic oscillator representing the resonance of the first resonance circuit RC1) and the second resonance circuit RC2
  • the quantum state (more specifically, the quantum state of the superconducting qubit configured by the second resonance circuit RC2) changes independently. That is, in this case, in the control circuit 1, the interaction between the first resonance circuit RC1 and the second resonance circuit RC2 has disappeared (that is, the interaction is off).
  • the control circuit 1 when the switch of the power supply PW is on, the first resonance circuit RC1 and the second resonance circuit RC2 are electrically coupled.
  • the energy of the second resonance circuit RC2 changes nonlinearly (trigonometrically in the example described above) in accordance with the change in energy of the first resonance circuit RC1.
  • the control circuit 1 includes a first phase phi 1, a second phase phi 2, a third phase phi 3, based on the fourth phase phi 4, the energy of the first resonant circuit RC1
  • the energy of the second resonance circuit RC2 changes nonlinearly according to the change.
  • it does not necessarily correspond to one to one.
  • the interaction between the first resonance circuit RC1 and the second resonance circuit RC2 is turned on / off (that is, generated / disappeared) in accordance with the on / off of the switch of the power supply PW. Can be switched.
  • FIG. 3 is a diagram for explaining the concept of a method for integrating the control circuit 1 two-dimensionally.
  • a mark MK1 is arranged at each contact point of the two-dimensional square lattice.
  • marks MK2 are arranged at positions on the two-dimensional square lattice at the midpoints of the marks MK1 and MK1.
  • each of the plurality of marks MK1 in FIG. 3 represents the first resonance circuit RC1 described above.
  • each of the plurality of marks MK2 in FIG. 3 indicates the above-described second resonance circuit RC2.
  • the line connecting the mark MK1 and the mark MK2 is as shown in FIG.
  • the first resonance circuit RC1 among the four Josephson junction elements (the first Josephson junction element J1 to the fourth Josephson junction element J4) included in each of the plurality of modulation circuits MC included in the integrated circuit.
  • the two Josephson junction elements nearer to the second resonance circuit are ⁇ -junction Josephson junction elements, and the two Josephson junction elements closer to the second resonance circuit RC2 are ⁇ -junction Josephson junction elements. Note that the reference numerals given to the elements of the control circuit 1 in FIG. 1 are omitted in FIG. 4 because the figure becomes complicated.
  • the partial circuit PC1 By integrating the plurality of control circuits 1 as shown in FIG. 4, for example, when each of the two power supply PWs included in the partial circuit PC1 is turned on, the partial circuit PC1 includes a single modulation circuit MC. Thus, an interaction occurs between the superconducting qubits formed by each of the two first resonance circuits RC1 included in the partial circuit PC1. In addition, when any one of the two power sources PW included in the partial circuit PC1 is turned off, the interaction between the superconducting qubits formed by the two first resonance circuits RC1 included in the partial circuit PC1 is caused. Disappear. As described above, by integrating a plurality of control circuits 1 as shown in FIG.
  • Modification 1 of the embodiment will be described with reference to FIGS. 5 and 6.
  • symbol is attached
  • FIG. 5 is a diagram illustrating an example of the configuration of the control circuit 2 according to the first modification of the embodiment.
  • the third resonance circuit RC3 is an annular circuit in which the inductor L in the second resonance circuit RC2 is replaced with a fifth Josephson junction element J5. That is, the third resonance circuit RC3 is an annular circuit including the fifth Josephson junction element J5, the third capacitor C3, and the fourth capacitor C4.
  • the control circuit 2 includes the first resonance circuit RC1 and the third resonance circuit RC3, the Hamiltonian structure of the control circuit 2 based on the circuit quantum electrodynamics is almost the same as the Hamiltonian represented by the above equation (1). It becomes the same structure. Therefore, when the switch of the power source PW is turned off, the phase phi Z always 0, the first resonance circuit RC1 in the control circuit 2 and the third resonant circuit RC3, can not be electrically coupled. As a result, in this case, the first resonance circuit RC1 and the third resonance circuit RC3 resonate independently of each other (independently of each other).
  • This is configured by a virtual spin representing two quantum states (that is,
  • 1>) has disappeared (the interaction must be off) ).
  • This is a phenomenon that occurs regardless of the magnitude of the Josephson energy of each of the first Josephson junction element J1 to the fourth Josephson junction element J4. For this reason, even if the strength of the interaction is increased, the interaction can be turned off in the control circuit 2 by turning off the switch of the power source PW.
  • each of the first resonance circuit RC1 and the third resonance circuit RC3 resonates according to the mutual resonance.
  • 1>) of the superconducting qubit formed by the third resonance circuit RC3 is formed by the first resonance circuit RC1.
  • 1>) of a superconducting qubit ie, the interaction between these two spins is generated) (That it is in an on state)).
  • the strength of the interaction increases as the Josephson energy of each of the first Josephson junction element J1 to the fourth Josephson junction element J4 increases. For this reason, in the control circuit 2, the strength of the interaction can be increased by increasing the Josephson energy.
  • the quantum computer having the integrated circuit shown in FIG. 6 can perform a plurality of first resonance circuits RC1 included in the integrated circuit during the quantum calculation. Even if an error occurs in any one of the superconducting qubits constituted by each of the third resonance circuits RC3 and the first resonance circuit RC3, the first resonance constituting the superconducting qubits As long as the switch of the power supply PW connected to the circuit RC1 is off, it is possible to prevent the error from propagating to the first resonance circuit RC1 or the third resonance circuit RC3 constituting another superconducting qubit. it can.
  • the control circuit 3 includes a modulation circuit MC, a second resonance circuit RC2, a fourth resonance circuit RC4, and a power supply PW.
  • the control circuit 3 may be configured to include other circuits in addition to these three circuits and the power supply PW. However, in this case, the other circuit must be provided in the control circuit 3 so as not to break the characteristics of the control circuit 3 described below. In other words, the control circuit 3 may be subjected to any changes as long as the characteristics of the control circuit 3 described below are not destroyed.
  • the fourth resonance circuit RC4 is a resonance circuit obtained by replacing the 0th Josephson junction element J0 with the circuit CC in the first resonance circuit RC1. That is, in the fourth resonance circuit RC4, the circuit CC is located between the first capacitor C1 and the second capacitor C2.
  • the circuit CC is a ring circuit including a sixth Josephson junction element J6, a seventh Josephson junction element J7, and an eighth Josephson junction element J8.
  • the fourth resonance circuit RC4 including the circuit CC resonates.
  • Each of the sixth Josephson junction element J6 and the seventh Josephson junction element J7 is a zero junction Josephson junction element. Note that one or both of the sixth Josephson junction element J6 and the seventh Josephson junction element J7 may be a ⁇ junction Josephson junction element instead of the 0 junction Josephson junction element.
  • the eighth Josephson junction element J8 is a ⁇ junction Josephson junction element.
  • the eighth Josephson junction element J8 may be a 0-junction Josephson junction element instead of the ⁇ -junction Josephson junction element.
  • the eighth Josephson junction element J8 is located between the sixth Josephson junction element J6 and the seventh Josephson junction element J7 in the circuit CC.
  • the first contact P1 and the first capacitor C1 and the sixth Josephson junction element J6 and the eighth Josephson junction element J8 are connected. Further, in the control circuit 3, the third contact P3 and the second capacitor C2 and the seventh Josephson junction element J7 and the eighth Josephson junction element J8 are connected.
  • the control circuit 3 includes the second resonance circuit RC2 and the fourth resonance circuit RC4, the Hamiltonian structure of the control circuit 3 based on the circuit quantum electrodynamics is almost the same as the Hamiltonian shown in the above equation (1). It becomes the same structure. Therefore, when the switch of the power source PW is turned off, the phase phi Z is always 0, the control circuit 3 and the second resonant circuit RC2 and the fourth resonant circuit RC4, can not be electrically coupled. As a result, in this case, the second resonance circuit RC2 and the fourth resonance circuit RC4 resonate independently of each other (independently of each other).
  • each of the control circuit 1 to control circuit 3 described above replaces the resonance circuit (for example, the first resonance circuit RC1 in the case of the control circuit 1) constituting the superconducting qubit with another qubit.
  • the structure to which the circuit to comprise may be connected may be sufficient.
  • the other qubits may be known qubits or qubits to be developed in the future.
  • the circuit is configured such that the current oscillates according to two quantum states of the qubit.
  • the modulation circuit (in the example described above, the modulation circuit MC) includes the first contact (in the example described above, the first contact P1) and the second contact (in the example described above, A second contact P2), a third contact (in the example described above, the third contact P3), and a fourth contact (in the example described above, the fourth contact P4),
  • a first resonance circuit (in the example described above, the first resonance circuit RC1) is connected to the third contact
  • a second resonance circuit (in the example described above, the second resonance circuit RC1) is connected to the second contact and the fourth contact.
  • a ring circuit to which a resonance circuit RC2) is connected and a first phase (in the example described above, the first phase ⁇ 1 ) that is a phase represented by time integration of the potential at the first contact, and a second phase Contact (in the example described above, second place A second phase that is a phase represented by time integration of the potential in the phase ⁇ 2 ) and a third phase that is a phase represented by time integration of the potential at the third contact (in the example described above, the third phase). and phi 3), in the example described in the fourth phase (above the phase represented by the time integral of the potential at the fourth contact point, based on the fourth phase phi 4) and the first resonant circuit and the second resonance
  • the coupling state with the circuit is changed.
  • the modulation circuit has a coupling state based on the first phase, the second phase, the third phase, and the fourth phase, and the first resonance circuit and the second resonance circuit are coupled.
  • the state is changed to either a state in which the first resonance circuit and the second resonance circuit are coupled to each other. Thereby, the modulation circuit can disconnect the electrical coupling between the first resonance circuit and the second resonance circuit.
  • the modulation circuit is supplied to each of the first resonance circuit and the second resonance circuit by a power source (in the example described above, the power source PW) that supplies an AC voltage to each of the first resonance circuit and the second resonance circuit.
  • a power source in the example described above, the power source PW
  • the coupling state is changed to a state where the first resonance circuit and the second resonance circuit are coupled, and the power supply to each of the first resonance circuit and the second resonance circuit is performed.
  • the coupling state is changed to a state where the first resonance circuit and the second resonance circuit are not coupled.
  • the modulation circuit can switch the coupling state of the first resonance circuit and the second resonance circuit according to the supply state of the AC voltage by the power source to each of the first resonance circuit and the second resonance circuit.
  • the modulation circuit includes a 0-junction first Josephson junction element (in the example described above, the first Josephson junction element J1) and a 0-junction second Josephson junction element (in the example described above, The second Josephson junction element J2), the third Josephson junction element of ⁇ junction (in the example described above, the third Josephson junction element J3), and the fourth Josephson junction element of ⁇ junction (described above).
  • a fourth Josephson junction element J4) is provided, the first Josephson junction element is located between the first contact and the second contact, and the second Josephson junction element is the second contact and the third contact.
  • the third Josephson junction element is located between the third contact and the fourth contact, and the fourth Josephson junction element is located between the fourth contact and the first contact.
  • the modulation circuit can switch the coupling state between the first resonance circuit and the second resonance circuit when at least one of the first resonance circuit and the second resonance circuit is a qubit circuit including a Josephson junction element. it can.
  • the modulation circuit includes a readout circuit in which a resonance circuit different from the qubit circuit among the first resonance circuit and the second resonance circuit reads the quantum state of the qubit circuit. Accordingly, the modulation circuit uses a resonance circuit different from the qubit circuit among the first resonance circuit and the second resonance circuit, and the quantum state of the resonance circuit that is the qubit circuit among the first resonance circuit and the second resonance circuit. Can be read out.
  • control circuit in the example described above, the control circuit 1 to the control circuit 3 includes the modulation circuit, the first resonance circuit, the second resonance circuit, the first resonance circuit, and the second resonance circuit described above. And a power supply for supplying an AC voltage to each of the circuits.
  • the frequency of the AC voltage supplied by the power supply is at least one of the resonance frequency of the first resonance circuit and the second resonance circuit.
  • the second resonance circuit of the second resonance circuit is changed according to the change of the quantum state of the first resonance circuit. The quantum state changes.
  • the quantum state of the second resonance circuit changes according to the change of the quantum state of the first resonance circuit.
  • the change in the quantum state of the second resonance circuit is in accordance with the first phase, the second phase, the third phase, the fourth phase, and the change in the quantum state of the first resonance circuit. It is a change. Thereby, the electrical coupling between the first resonance circuit and the second resonance circuit can be cut.
  • the control circuit when the supply of AC voltage to each of the first resonance circuit and the second resonance circuit is stopped by the power supply, the control circuit has a quantum state of the first resonance circuit and a quantum state of the second resonance circuit. It changes independently. Thereby, the control circuit stops the supply of the AC voltage to each of the first resonance circuit and the second resonance circuit by the power source, thereby changing the coupling state between the first resonance circuit and the second resonance circuit to the first resonance circuit. It is possible to switch to a state where the resonance circuit and the second resonance circuit are not coupled.

Abstract

A modulation circuit comprising a ring circuit having a first contact, a second contact, a third contact, and a fourth contact, wherein a first resonator circuit is connected to the first contact and the third contact, and a second resonator circuit is connected to the second contact and the fourth contact. The coupling state of the first resonator circuit and the second resonator circuit is varied on the basis of a first phase expressed by the time integral of a potential at the first contact, a second phase expressed by the time integral of a potential at the second contact, a third phase expressed by the time integral of a potential at the third contact, and a fourth phase expressed by the time integral of a potential at the fourth contact.

Description

変調回路、制御回路、情報処理装置、及び集積方法Modulation circuit, control circuit, information processing apparatus, and integration method
　本発明は、変調回路、制御回路、情報処理装置、及び集積方法に関する。
　本願は、２０１７年０３月０３日に、日本に出願された特願２０１７－０４０３７８号に基づき優先権を主張し、その内容をここに援用する。 The present invention relates to a modulation circuit, a control circuit, an information processing apparatus, and an integration method.
This application claims priority on March 03, 2017 based on Japanese Patent Application No. 2017-040378 filed in Japan, the contents of which are incorporated herein by reference.
　量子計算機に関する技術の研究や開発が行われている。 Research and development of technologies related to quantum computers are being conducted.
　これに関し、超伝導量子ビットを用いた量子計算機において２量子ビットゲート操作を行う方法が知られている（特許文献１、２参照）。 In this regard, a method of performing a two-qubit gate operation in a quantum computer using superconducting qubits is known (see Patent Documents 1 and 2).
米国特許第７６１３７６５号明細書U.S. Pat. No. 7,613,765 米国特許出願公開第２０１６／０３８０６３６号明細書US Patent Application Publication No. 2016/0380636
　ここで、超伝導量子ビットは、ジョセフソン接合によってもたらされる非線形性を利用した非調和的な共振回路によって構成される。また、ある２つの超伝導量子ビットに対して２量子ビットゲート操作を行う場合、当該２つの超伝導量子ビットの状態は、当該２つの超伝導量子ビット間に相互作用が生じている状態でなければならない。当該２つの超伝導量子ビット間に相互作用が生じている状態とは、２つの超伝導量子ビットのそれぞれを構成する共振回路同士が電気的に結合している状態のことである。そして、当該２つの超伝導量子ビットに対する２量子ビットゲート操作では、２量子ビットゲート操作の時間短縮や精度向上等の目的の観点から、当該２つの超伝導量子ビット間の相互作用が強いことが望ましい。なお、ここでは、２つの共振回路同士が電気的に結合している状態とは、一方の共振回路から他方の共振回路に電流が流れている状態を意味し、これら２つの共振回路同士が配線によって物理的に接続されていることを意味しているわけではない。また、２つの共振回路同士が電気的に結合していない状態（２つの共振回路同士の電気的な結合が切れている状態）とは、一方の共振回路から他方の共振回路に電流が流れていない状態を意味し、これら２つの共振回路同士が配線によって物理的に接続されていないことを意味しているわけではない。一方、当該２つの超伝導量子ビットに対して２量子ビットゲート操作を行わない場合に当該２つの超伝導量子ビット間に相互作用が生じていると、当該２つの超伝導量子ビットを備える量子計算機は、量子計算において誤りを生じさせてしまうことがある。このため、当該場合において当該２つの超伝導量子ビットの状態は、当該２つの超伝導量子ビット間に相互作用が生じていない状態でなければならない。当該２つの超伝導量子ビット間に相互作用が生じていない状態とは、当該２つの超伝導量子ビットのそれぞれを構成する共振回路同士が電気的に結合していない状態のことである。 Here, the superconducting qubit is composed of an anharmonic resonance circuit that utilizes the nonlinearity caused by the Josephson junction. In addition, when performing a two-qubit gate operation on a certain two superconducting qubits, the state of the two superconducting qubits must be a state in which an interaction occurs between the two superconducting qubits. I must. The state in which the interaction is generated between the two superconducting qubits is a state in which the resonance circuits constituting each of the two superconducting qubits are electrically coupled. In the two-qubit gate operation for the two superconducting qubits, the interaction between the two superconducting qubits may be strong from the viewpoint of shortening the time or improving the accuracy of the two-qubit gate operation. desirable. Here, the state in which the two resonance circuits are electrically coupled to each other means a state in which a current flows from one resonance circuit to the other resonance circuit, and the two resonance circuits are connected to each other. Does not mean that they are physically connected by. In addition, the state in which the two resonance circuits are not electrically coupled (the state in which the two resonance circuits are not electrically coupled) is a state in which current flows from one resonance circuit to the other resonance circuit. This means that the two resonance circuits are not physically connected to each other by wiring. On the other hand, when no two-qubit gate operation is performed on the two superconducting qubits and an interaction occurs between the two superconducting qubits, a quantum computer including the two superconducting qubits May cause errors in quantum computation. For this reason, in this case, the state of the two superconducting qubits must be such that no interaction occurs between the two superconducting qubits. The state where no interaction occurs between the two superconducting qubits is a state where the resonance circuits constituting each of the two superconducting qubits are not electrically coupled to each other.
　しかしながら、従来の方法では、上記の２つの超伝導量子ビットのそれぞれを構成する共振回路同士が電気的に結合している状態を、当該共振回路同士が電気的に結合していない状態に切り替えた場合、当該共振回路同士の電気的な結合が切れず（消えず）に残る場合があった。その結果、当該方法では、当該２つの超伝導量子ビットを備える量子計算機が行う量子計算において誤りを生じさせる場合があった。 However, in the conventional method, the state where the resonance circuits constituting each of the two superconducting qubits are electrically coupled is switched to the state where the resonance circuits are not electrically coupled. In some cases, the electrical coupling between the resonance circuits may remain unbroken (do not disappear). As a result, in this method, an error may occur in the quantum calculation performed by the quantum computer including the two superconducting qubits.
　そこで本発明は、上記従来技術の問題に鑑みてなされたものであり、第１共振回路と第２共振回路の電気的な結合を切ることができる変調回路、制御回路、情報処理装置、及び集積方法を提供する。 Accordingly, the present invention has been made in view of the above-described problems of the prior art, and includes a modulation circuit, a control circuit, an information processing apparatus, and an integrated circuit that can cut off electrical coupling between the first resonance circuit and the second resonance circuit. Provide a method.
　上記課題の少なくとも一つを解決するために本発明の一態様は、第１接点と、第２接点と、第３接点と、第４接点とを有し、前記第１接点と前記第３接点とに第１共振回路が接続され、前記第２接点と前記第４接点とに第２共振回路が接続された環状回路であって、前記第１接点における電位の時間積分によって表される位相である第１位相と、前記第２接点における電位の時間積分によって表される位相である第２位相と、前記第３接点における電位の時間積分によって表される位相である第３位相と、前記第４接点における電位の時間積分によって表される位相である第４位相とに基づいて、前記第１共振回路と前記第２共振回路との結合状態を変化させる、変調回路である。 In order to solve at least one of the above problems, one embodiment of the present invention includes a first contact, a second contact, a third contact, and a fourth contact, and the first contact and the third contact. A first resonance circuit is connected to the second contact and the fourth contact is connected to the second resonance circuit, and a phase represented by time integration of the potential at the first contact. A first phase, a second phase that is a phase represented by time integration of a potential at the second contact, a third phase that is a phase represented by time integration of a potential at the third contact, The modulation circuit changes a coupling state between the first resonance circuit and the second resonance circuit based on a fourth phase that is a phase represented by time integration of potentials at four contacts.
　また、本発明の他の態様は、変調回路において、前記第１位相と、前記第２位相と、前記第３位相と、前記第４位相とに基づいて、前記結合状態を、前記第１共振回路と前記第２共振回路とが結合していない状態と、前記第１共振回路と前記第２共振回路とが結合している状態とのいずれかに変化させる、構成が用いられてもよい。 According to another aspect of the present invention, in the modulation circuit, the coupling state is changed to the first resonance based on the first phase, the second phase, the third phase, and the fourth phase. A configuration in which the circuit and the second resonance circuit are not coupled to each other and the state in which the first resonance circuit and the second resonance circuit are coupled may be used.
　また、本発明の他の態様は、変調回路において、前記第１共振回路と前記第２共振回路とのそれぞれに交流電圧を供給する電源により前記第１共振回路と前記第２共振回路とのそれぞれへの前記交流電圧の供給が開始された場合、前記結合状態を前記第１共振回路と前記第２共振回路とが結合している状態に変化させ、前記電源により前記第１共振回路と前記第２共振回路とのそれぞれへの前記交流電圧の供給が停止された場合、前記結合状態を前記第１共振回路と前記第２共振回路とが結合していない状態に変化させる、構成が用いられてもよい。 According to another aspect of the present invention, in the modulation circuit, each of the first resonance circuit and the second resonance circuit is supplied from a power source that supplies an AC voltage to each of the first resonance circuit and the second resonance circuit. When the supply of the AC voltage to the power source is started, the coupled state is changed to a state in which the first resonant circuit and the second resonant circuit are coupled, and the first resonant circuit and the first resonant circuit are changed by the power source. When the supply of the AC voltage to each of the two resonance circuits is stopped, the coupling state is changed to a state where the first resonance circuit and the second resonance circuit are not coupled. Also good.
　また、本発明の他の態様は、変調回路において、前記第１接点と前記第２接点との間に位置する０接合の第１ジョセフソン接合素子を備えた、構成が用いられてもよい。 Further, in another aspect of the present invention, a configuration may be used in which a first junction Josephson junction element of 0 junction located between the first contact and the second contact is provided in the modulation circuit.
　また、本発明の他の態様は、変調回路において、前記第２接点と前記第３接点との間に位置する０接合の第２ジョセフソン接合素子を備えた、構成が用いられてもよい。 Further, in another aspect of the present invention, a configuration may be used in which the modulation circuit includes a second Josephson junction element with 0 junction positioned between the second contact and the third contact.
　また、本発明の他の態様は、変調回路において、前記第３接点と前記第４接点との間に位置するπ接合の第３ジョセフソン接合素子を備えた、構成が用いられてもよい。 In another aspect of the present invention, a configuration may be used in which the modulation circuit includes a third Josephson junction element having a π junction positioned between the third contact and the fourth contact.
　また、本発明の他の態様は、変調回路において、前記第４接点と前記第１接点との間に位置するπ接合の第４ジョセフソン接合素子を備えた、構成が用いられてもよい。 Further, in another aspect of the present invention, a configuration may be used in which the modulation circuit includes a fourth Josephson junction element having a π junction located between the fourth contact and the first contact.
　また、本発明の他の態様は、変調回路において、前記第１共振回路と前記第２共振回路のうちの少なくとも一方が、ジョセフソン接合素子を含む量子ビット回路である、構成が用いられてもよい。 Further, according to another aspect of the present invention, in the modulation circuit, a configuration in which at least one of the first resonance circuit and the second resonance circuit is a qubit circuit including a Josephson junction element is used. Good.
　また、本発明の他の態様は、変調回路において、前記第１共振回路と前記第２共振回路のうちのいずれか一方が、ジョセフソン接合素子を含む量子ビット回路である、構成が用いられてもよい。 According to another aspect of the present invention, there is used a configuration in which one of the first resonance circuit and the second resonance circuit is a qubit circuit including a Josephson junction element in a modulation circuit. Also good.
　また、本発明の他の態様は、変調回路において、前記第１共振回路と前記第２共振回路のうち前記量子ビット回路と異なる共振回路が、前記量子ビット回路の量子状態を読み出す読出回路を備える、構成が用いられてもよい。 According to another aspect of the present invention, in the modulation circuit, a resonance circuit different from the qubit circuit in the first resonance circuit and the second resonance circuit includes a readout circuit that reads a quantum state of the qubit circuit. A configuration may be used.
　また、本発明の他の態様は、上記に記載の変調回路と、前記第１共振回路と、前記第２共振回路と、前記第１共振回路と前記第２共振回路とのそれぞれに交流電圧を供給する電源と、を備える制御回路である。 According to another aspect of the present invention, an alternating voltage is applied to each of the modulation circuit described above, the first resonance circuit, the second resonance circuit, the first resonance circuit, and the second resonance circuit. And a power supply to be supplied.
　また、本発明の他の態様は、制御回路において、前記電源が供給する交流電圧の周波数は、前記第１共振回路と前記第２共振回路とのうち少なくとも一方の共振周波数である、構成が用いられてもよい。 According to another aspect of the present invention, in the control circuit, the configuration in which the frequency of the AC voltage supplied from the power source is at least one of the first resonance circuit and the second resonance circuit is used. May be.
　また、本発明の他の態様は、制御回路において、前記電源により前記第１共振回路と前記第２共振回路とのそれぞれへの前記交流電圧の供給が開始された場合、前記第１共振回路の量子状態の変化に応じて前記第２共振回路の量子状態が変化する、構成が用いられてもよい。 According to another aspect of the present invention, in the control circuit, when the supply of the AC voltage to each of the first resonance circuit and the second resonance circuit is started by the power source, the first resonance circuit A configuration in which the quantum state of the second resonance circuit changes in accordance with the change of the quantum state may be used.
　また、本発明の他の態様は、制御回路において、前記第２共振回路の量子状態の変化は、前記第１位相と、前記第２位相と、前記第３位相と、前記第４位相と、前記第１共振回路の量子状態の変化とに応じた変化である、構成が用いられてもよい。 According to another aspect of the present invention, in the control circuit, the change in the quantum state of the second resonance circuit includes the first phase, the second phase, the third phase, and the fourth phase. A configuration that is a change according to a change in the quantum state of the first resonance circuit may be used.
　また、本発明の他の態様は、制御回路において、前記電源により前記第１共振回路と前記第２共振回路とのそれぞれへの前記交流電圧の供給が停止された場合、前記第１共振回路の量子状態と、前記第２共振回路の量子状態とが独立に変化する、構成が用いられてもよい。 According to another aspect of the present invention, in the control circuit, when the supply of the AC voltage to each of the first resonance circuit and the second resonance circuit is stopped by the power source, the first resonance circuit A configuration in which the quantum state and the quantum state of the second resonance circuit change independently may be used.
　また、本発明の他の態様は、上記に記載の変調回路を備える、情報処理装置である。 Another aspect of the present invention is an information processing apparatus including the modulation circuit described above.
　また、本発明の他の態様は、上記に記載の制御回路を備える、情報処理装置である。 Another aspect of the present invention is an information processing apparatus including the control circuit described above.
　また、本発明の他の態様は、上記に記載の変調回路を介して複数の前記第１共振回路と複数の前記第２共振回路とを交互に接続し、前記第１共振回路と前記第２共振回路とを二次元的又は三次元的に集積する、集積方法である。 In another aspect of the present invention, a plurality of the first resonance circuits and a plurality of the second resonance circuits are alternately connected via the modulation circuit described above, and the first resonance circuit and the second resonance circuit are connected. This is an integration method in which resonance circuits are integrated two-dimensionally or three-dimensionally.
　本発明によれば、第１共振回路と第２共振回路とが結合した場合における結合の強さを強くしつつ、第１共振回路と第２共振回路の結合状態を切り替えることができる。 According to the present invention, the coupling state of the first resonance circuit and the second resonance circuit can be switched while increasing the strength of coupling when the first resonance circuit and the second resonance circuit are coupled.
実施形態に係る制御回路１の構成の一例を示す図である。It is a figure which shows an example of a structure of the control circuit 1 which concerns on embodiment. 位相φＷ、位相φｑ、位相φｒ、位相φＺのそれぞれが０ではない値となる場合において、第１接点Ｐ１、第２接点Ｐ２、第３接点Ｐ３、第４接点Ｐ４のそれぞれにおける電位の組み合わせのうちの特徴的な組み合わせの一例を示した図である。When the phase φ W , the phase φ q , the phase φ r , and the phase φ Z are non-zero values, the potentials at the first contact P1, the second contact P2, the third contact P3, and the fourth contact P4, respectively. It is the figure which showed an example of the characteristic combination among these combinations. 制御回路１を二次元的に集積化する方法の概念を説明するための図である。It is a figure for demonstrating the concept of the method of integrating the control circuit 1 two-dimensionally. 図３に示した概念に基づいて複数の制御回路１を集積させた集積回路の一例を示す図である。It is a figure which shows an example of the integrated circuit which integrated the some control circuit 1 based on the concept shown in FIG. 実施形態の変形例１に係る制御回路２の構成の一例を示す図である。It is a figure which shows an example of a structure of the control circuit 2 which concerns on the modification 1 of embodiment. 複数の制御回路２を集積させた集積回路の一例を示す図である。2 is a diagram illustrating an example of an integrated circuit in which a plurality of control circuits 2 are integrated. FIG. 実施形態の変形例２に係る制御回路３の構成の一例を示す図である。It is a figure which shows an example of a structure of the control circuit 3 which concerns on the modification 2 of embodiment.
　＜実施形態＞
　以下、本発明の実施形態について、図面を参照して説明する。 <Embodiment>
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
　＜制御回路の概要＞
　まず、実施形態に係る制御回路１の概要について説明する。
　制御回路１は、情報処理装置のうち超伝導量子ビットを用いて量子計算を行う情報処理装置である量子計算機に備えられる回路である。より具体的には、当該量子計算機は、複数の制御回路１が二次元的又は三次元的に集積された集積回路を備える。ここでは、このような制御回路１の概要について説明する。 <Outline of control circuit>
First, an outline of the control circuit 1 according to the embodiment will be described.
The control circuit 1 is a circuit provided in a quantum computer that is an information processing apparatus that performs quantum computation using superconducting qubits among information processing apparatuses. More specifically, the quantum computer includes an integrated circuit in which a plurality of control circuits 1 are integrated two-dimensionally or three-dimensionally. Here, an outline of such a control circuit 1 will be described.
　超伝導量子ビットは、共振回路によって構成される。また、超伝導量子ビットを用いて量子計算を行う量子計算機は、１以上の超伝導量子ビットを対象にしてゲート操作を行い、量子計算を行う。超伝導量子ビットに対して行うゲート操作のうち、ある２つの超伝導量子ビットを対象にして行われる２量子ビットゲート操作を当該量子計算機が行う場合、当該２つの超伝導量子ビットの状態は、当該２つの超伝導量子ビット間に相互作用が生じている状態でなければならない。当該２つの超伝導量子ビット間に相互作用が生じている状態とは、当該２つの超伝導量子ビットのそれぞれを構成する共振回路同士が電気的に結合している状態のことである。そして、当該２つの超伝導量子ビットに対する２量子ビットゲート操作では、２量子ビットゲート操作の安定性等の理由から、当該２つの超伝導量子ビット間の相互作用が強いことが望ましい。一方、当該２つの超伝導量子ビットに対して２量子ビットゲート操作を行わない場合に当該２つの超伝導量子ビット間に相互作用が生じていると、当該２つの超伝導量子ビットを備える量子計算機は、量子計算において誤りを生じさせてしまうことがある。このため、当該場合において当該２つの超伝導量子ビットの状態は、当該２つの超伝導量子ビット間に相互作用が生じていない状態でなければならない。当該２つの超伝導量子ビット間に相互作用が生じていない状態とは、すなわち、２つの超伝導量子ビットのそれぞれを構成する共振回路同士が電気的に結合していない状態のことである。なお、本実施形態では、２つの共振回路同士が電気的に結合している状態とは、一方の共振回路から他方の共振回路に電流が流れている状態を意味し、これら２つの共振回路同士が配線によって物理的に接続されていることを意味しているわけではない。また、２つの共振回路同士が電気的に結合していない状態（２つの共振回路同士の電気的な結合が切れている状態）とは、一方の共振回路から他方の共振回路に電流が流れていない状態を意味し、これら２つの共振回路同士が配線によって物理的に接続されていないことを意味しているわけではない。 The superconducting qubit is composed of a resonant circuit. In addition, a quantum computer that performs quantum computation using a superconducting qubit performs quantum computation by performing a gate operation on one or more superconducting qubits. When the quantum computer performs a two-qubit gate operation performed on a certain two superconducting qubits among the gate operations performed on the superconducting qubits, the state of the two superconducting qubits is: There must be an interaction between the two superconducting qubits. The state where the interaction occurs between the two superconducting qubits is a state where the resonance circuits constituting each of the two superconducting qubits are electrically coupled. In the two-qubit gate operation for the two superconducting qubits, it is desirable that the interaction between the two superconducting qubits is strong for reasons such as the stability of the two-qubit gate operation. On the other hand, when no two-qubit gate operation is performed on the two superconducting qubits and an interaction occurs between the two superconducting qubits, a quantum computer including the two superconducting qubits May cause errors in quantum computation. For this reason, in this case, the state of the two superconducting qubits must be such that no interaction occurs between the two superconducting qubits. The state in which no interaction occurs between the two superconducting qubits means that the resonance circuits constituting each of the two superconducting qubits are not electrically coupled to each other. In the present embodiment, the state in which the two resonance circuits are electrically coupled to each other means a state in which a current flows from one resonance circuit to the other resonance circuit. Does not mean that they are physically connected by wiring. In addition, the state in which the two resonance circuits are not electrically coupled (the state in which the two resonance circuits are not electrically coupled) is a state in which current flows from one resonance circuit to the other resonance circuit. This means that the two resonance circuits are not physically connected to each other by wiring.
　しかしながら、制御回路１と異なる制御回路Ｘ（例えば、従来の制御回路）では、上記の２つの超伝導量子ビットのそれぞれを構成する共振回路同士が電気的に結合している状態を、当該共振回路同士が電気的に結合していない状態に切り替えた場合、当該共振回路同士の電気的な結合が切れず（消えず）に残る場合があった。その結果、制御回路Ｘでは、当該２つの超伝導量子ビットを備える量子計算機が行う量子計算において誤りを生じさせる場合があった。 However, in a control circuit X (for example, a conventional control circuit) different from the control circuit 1, the resonance circuit constituting each of the two superconducting qubits is electrically coupled to each other. When switching to a state where they are not electrically coupled to each other, there is a case where the electrical coupling between the resonance circuits is not cut (disappears). As a result, in the control circuit X, an error may occur in the quantum calculation performed by the quantum computer including the two superconducting qubits.
　そこで、制御回路１は、第１接点Ｐ１と、第２接点Ｐ２と、第３接点Ｐ３と、第４接点Ｐ４とを有し、第１接点Ｐ１と第３接点Ｐ３とに第１共振回路ＲＣ１が接続され、第２接点Ｐ２と第４接点Ｐ４とに第２共振回路ＲＣ２が接続された環状回路であって、第１接点Ｐ１における電位の時間積分によって表される位相である第１位相と、第２接点Ｐ２における電位の時間積分によって表される位相である第２位相と、第３接点Ｐ３における電位の時間積分によって表される位相である第３位相と、第４接点Ｐ４における電位の時間積分によって表される位相である第４位相とに基づいて、第１共振回路ＲＣ１と第２共振回路ＲＣ２との結合状態を変化させる。これにより、制御回路１は、第１共振回路ＲＣ１と第２共振回路ＲＣ２の電気的な結合を切ることができる。すなわち、複数の制御回路１が集積された集積回路を備える量子計算機は、ある２量子ビットゲート操作を行う際、当該相互作用がオンである状態とオフである状態とを切り替えることができる。当該２つの超伝導量子ビット間の相互作用がオンの状態とは、当該２つの超伝導量子ビット間に相互作用が生じている状態のことである。また、当該２つの超伝導量子ビット間の相互作用がオフの状態とは、当該２つの超伝導量子ビット間に相互作用が消失している（切れている）状態のことである。すなわち、制御回路１は、当該相互作用がオンの状態とオフの状態とを切り替えることができるスイッチ回路である。 Therefore, the control circuit 1 has a first contact P1, a second contact P2, a third contact P3, and a fourth contact P4. The first resonance circuit RC1 is connected to the first contact P1 and the third contact P3. Are connected to each other, and the second resonance circuit RC2 is connected to the second contact P2 and the fourth contact P4, the first phase being a phase expressed by time integration of the potential at the first contact P1; , A second phase that is a phase represented by time integration of the potential at the second contact P2, a third phase that is a phase represented by time integration of the potential at the third contact P3, and a potential at the fourth contact P4. The coupling state between the first resonance circuit RC1 and the second resonance circuit RC2 is changed based on the fourth phase that is a phase represented by time integration. Thereby, the control circuit 1 can cut | disconnect the electrical coupling of 1st resonance circuit RC1 and 2nd resonance circuit RC2. That is, a quantum computer including an integrated circuit in which a plurality of control circuits 1 are integrated can switch between a state in which the interaction is on and a state in which the interaction is off when performing a certain two-qubit gate operation. The state in which the interaction between the two superconducting qubits is on is a state in which an interaction occurs between the two superconducting qubits. The state in which the interaction between the two superconducting qubits is off is a state in which the interaction between the two superconducting qubits has disappeared (disconnected). That is, the control circuit 1 is a switch circuit that can switch between the on state and the off state of the interaction.
　なお、制御回路１は、量子計算機に代えて、他の情報処理装置に備えられる構成であってもよい。この場合、上記の第１共振回路ＲＣ１と第２共振回路ＲＣ２のそれぞれは、超伝導量子ビットを構成しなくてもよい（すなわち、後述する量子ビット回路でなくてもよい）。また、本実施形態において登場する電位は、制御回路１におけるある点（例えば、グラウンドの電位）の電位を基準とした電位である。 Note that the control circuit 1 may be configured to be provided in another information processing apparatus instead of the quantum computer. In this case, each of the first resonance circuit RC1 and the second resonance circuit RC2 may not constitute a superconducting qubit (that is, it may not be a qubit circuit described later). Further, the potential appearing in the present embodiment is a potential based on the potential at a certain point (for example, ground potential) in the control circuit 1.
　ここで、第１位相、第２位相、第３位相、第４位相のそれぞれについて説明する。
　第１位相は、前述した通り、第１接点Ｐ１における電位の時間積分によって表される位相である。より具体的には、第１位相は、第１接点Ｐ１における電位の時間積分に対して、ある物理定数を乗算することによって算出される。当該物理定数についてと、第１位相の算出方法については、既知であるため説明を省略する（回路量子電磁力学参照）。
　第２位相は、第１位相の場合と同様に、第２接点Ｐ２における電位の時間積分によって表される。
　第３位相は、第１位相の場合と同様に、第３接点Ｐ３における電位の時間積分によって表される。
　第４位相は、第１位相の場合と同様に、第４接点Ｐ４における電位の時間積分によって表される。 Here, each of the first phase, the second phase, the third phase, and the fourth phase will be described.
As described above, the first phase is a phase represented by time integration of the potential at the first contact P1. More specifically, the first phase is calculated by multiplying the time integral of the potential at the first contact P1 by a certain physical constant. Since the physical constant and the calculation method of the first phase are known, the description thereof is omitted (see circuit quantum electrodynamics).
The second phase is represented by the time integration of the potential at the second contact P2 as in the case of the first phase.
The third phase is represented by time integration of the potential at the third contact P3, as in the case of the first phase.
The fourth phase is represented by the time integration of the potential at the fourth contact P4 as in the case of the first phase.
　＜制御回路の構成＞
　まず、図１を参照し、制御回路１の構成について説明する。図１は、実施形態に係る制御回路１の構成の一例を示す図である。 <Configuration of control circuit>
First, the configuration of the control circuit 1 will be described with reference to FIG. FIG. 1 is a diagram illustrating an example of a configuration of a control circuit 1 according to the embodiment.
　制御回路１は、変調回路ＭＣと、第１共振回路ＲＣ１と、第２共振回路ＲＣ２と、電源ＰＷを備える。なお、制御回路１は、これら３つの回路及び電源ＰＷに加えて、他の回路を備える構成であってもよい。ただし、この場合、当該他の回路は、以下において説明する制御回路１が有する特徴を壊さないように制御回路１に備えられなければならない。換言すると、以下において説明する制御回路１が有する特徴を壊さなければ、制御回路１は、如何なる変更を受けてもよい。 The control circuit 1 includes a modulation circuit MC, a first resonance circuit RC1, a second resonance circuit RC2, and a power supply PW. The control circuit 1 may be configured to include other circuits in addition to these three circuits and the power supply PW. However, in this case, the other circuit must be provided in the control circuit 1 so as not to break the characteristics of the control circuit 1 described below. In other words, the control circuit 1 may be subjected to any changes as long as the characteristics of the control circuit 1 described below are not destroyed.
　変調回路ＭＣは、図１に示したように、第１接点Ｐ１と、第２接点Ｐ２と、第３接点Ｐ３と、第４接点Ｐ４とを有する。また、変調回路ＭＣは、第１接点Ｐ１と第３接点Ｐ３とに第１共振回路ＲＣ１が接続され、第２接点Ｐ２と第４接点Ｐ４とに第２共振回路ＲＣ２が接続された環状回路である。 As shown in FIG. 1, the modulation circuit MC has a first contact P1, a second contact P2, a third contact P3, and a fourth contact P4. The modulation circuit MC is an annular circuit in which the first resonance circuit RC1 is connected to the first contact P1 and the third contact P3, and the second resonance circuit RC2 is connected to the second contact P2 and the fourth contact P4. is there.
　また、変調回路ＭＣは、第１ジョセフソン接合素子Ｊ１と、第２ジョセフソン接合素子Ｊ２と、第３ジョセフソン接合素子Ｊ３と、第４ジョセフソン接合素子Ｊ４を備える。 In addition, the modulation circuit MC includes a first Josephson junction element J1, a second Josephson junction element J2, a third Josephson junction element J3, and a fourth Josephson junction element J4.
　第１ジョセフソン接合素子Ｊ１は、０接合のジョセフソン接合素子である。ここで、０接合のジョセフソン接合素子は、接合の両側の接点の間の位相差が０の場合にエネルギーが最小化されるジョセフソン接合のことである。また、第１ジョセフソン接合素子Ｊ１は、ＥＪｃジュール（又は電子ボルト）のジョセフソンエネルギーを有するジョセフソン接合素子である。第１ジョセフソン接合素子Ｊ１は、第１接点Ｐ１と第２接点Ｐ２との間に位置する。
　第２ジョセフソン接合素子Ｊ２は、０接合のジョセフソン接合素子である。また、第２ジョセフソン接合素子Ｊ２は、ＥＪｃジュール（又は電子ボルト）のジョセフソンエネルギーを有するジョセフソン接合素子である。第２ジョセフソン接合素子Ｊ２は、第２接点Ｐ２と第３接点Ｐ３との間に位置する。
　第３ジョセフソン接合素子Ｊ３は、π接合のジョセフソン接合素子である。π接合のジョセフソン接合素子は、接合の両側の接点の間の位相差がπの場合にエネルギーが最小化されるジョセフソン接合のことである。また、第３ジョセフソン接合素子Ｊ３は、ＥＪｃジュール（又は電子ボルト）のジョセフソンエネルギーを有するジョセフソン接合素子である。第３ジョセフソン接合素子Ｊ３は、第３接点Ｐ３と第４接点Ｐ４との間に位置する。
　第４ジョセフソン接合素子Ｊ４は、π接合のジョセフソン接合素子である。また、第４ジョセフソン接合素子Ｊ４は、ＥＪｃジュール（又は電子ボルト）のジョセフソンエネルギーを有するジョセフソン接合素子である。第４ジョセフソン接合素子Ｊ４は、第４接点Ｐ４と第１接点Ｐ１との間に位置する。 The first Josephson junction element J1 is a zero junction Josephson junction element. Here, a zero junction Josephson junction element is a Josephson junction in which energy is minimized when the phase difference between the contacts on both sides of the junction is zero. The first Josephson junction element J1 is a Josephson junction element having Josephson energy of E Jc joule (or electron volt). The first Josephson junction element J1 is located between the first contact P1 and the second contact P2.
The second Josephson junction element J2 is a zero junction Josephson junction element. The second Josephson junction element J2 is a Josephson junction element having Josephson energy of E Jc joule (or electron volt). The second Josephson junction element J2 is located between the second contact P2 and the third contact P3.
The third Josephson junction element J3 is a π-junction Josephson junction element. A π-junction Josephson junction element is a Josephson junction whose energy is minimized when the phase difference between the contacts on both sides of the junction is π. The third Josephson junction element J3 is a Josephson junction element having Josephson energy of E Jc joule (or electron volt). The third Josephson junction element J3 is located between the third contact P3 and the fourth contact P4.
The fourth Josephson junction element J4 is a π-junction Josephson junction element. The fourth Josephson device J4 is a Josephson device having a Josephson energy E Jc joules (or electron volts). The fourth Josephson junction element J4 is located between the fourth contact P4 and the first contact P1.
　第１共振回路ＲＣ１と第２共振回路ＲＣ２のうちの少なくとも一方は、ジョセフソン接合素子を含む量子ビット回路、すなわち超伝導量子ビットをジョセフソン接合素子によって構成する量子ビット回路である。本実施形態では、一例として、第１共振回路ＲＣ１のみが当該量子ビット回路である場合について説明する。 At least one of the first resonance circuit RC1 and the second resonance circuit RC2 is a qubit circuit including a Josephson junction element, that is, a qubit circuit in which a superconducting qubit is configured by a Josephson junction element. In the present embodiment, as an example, a case where only the first resonance circuit RC1 is the qubit circuit will be described.
　第１共振回路ＲＣ１は、第０ジョセフソン接合素子Ｊ０と、第１キャパシターＣ１と、第２キャパシターＣ２を備える環状回路である。ここで、第０ジョセフソン接合素子Ｊ０がインダクターとして振る舞うため、第１共振回路ＲＣ１は、共振する。 The first resonance circuit RC1 is an annular circuit including a 0th Josephson junction element J0, a first capacitor C1, and a second capacitor C2. Here, since the 0th Josephson junction element J0 behaves as an inductor, the first resonance circuit RC1 resonates.
　第０ジョセフソン接合素子Ｊ０は、０接合のジョセフソン接合素子である。また、第０ジョセフソン接合素子Ｊ０は、ＥＪｑジュール（又は電子ボルト）のジョセフソンエネルギーを有するジョセフソン接合素子である。第０ジョセフソン接合素子Ｊ０は、第１キャパシターＣ１と第２キャパシターＣ２との間に位置する。また、第０ジョセフソン接合素子Ｊ０は、静電容量が２×Ｃｃファラドのキャパシターとしても振る舞う。ここで、当該Ｃｃファラドに乗算されている係数である２は、後述するハミルトニアンの表式を簡単にするための係数である。なお、第０ジョセフソン接合素子Ｊ０は、０接合のジョセフソン接合素子に代えて、π接合のジョセフソン接合素子であってもよい。
　第１キャパシターＣ１は、静電容量が２×Ｃｑファラドのキャパシターである。ここで、当該Ｃｑファラドに乗算されている係数である２は、後述するハミルトニアンの表式を簡単にするための係数である。
　第２キャパシターＣ２は、静電容量が第１キャパシターＣ１の静電容量と同じキャパシターである。 The 0th Josephson junction element J0 is a 0 junction Josephson junction element. The 0th Josephson junction element J0 is a Josephson junction element having Josephson energy of E Jq Joule (or electron volt). The 0th Josephson junction element J0 is located between the first capacitor C1 and the second capacitor C2. The 0th Josephson junction element J0 also behaves as a capacitor having a capacitance of 2 × C c farad. Here, the coefficient 2 multiplied by the C c farad is a coefficient for simplifying the expression of the Hamiltonian described later. The 0th Josephson junction element J0 may be a π junction Josephson junction element instead of the 0 junction Josephson junction element.
The first capacitor C1 is the capacitance is a capacitor of 2 × C q farads. Here, 2 the a C q Farad coefficients are multiplied is a factor in order to simplify the expression for Hamiltonian described later.
The second capacitor C2 is a capacitor having the same capacitance as that of the first capacitor C1.
　第２共振回路ＲＣ２は、インダクターＬと、第３キャパシターＣ３と、第４キャパシターＣ４を備える環状回路である。すなわち、第２共振回路ＲＣ２は、この一例において、ＬＣ共振回路である。 The second resonance circuit RC2 is an annular circuit including an inductor L, a third capacitor C3, and a fourth capacitor C4. That is, the second resonance circuit RC2 is an LC resonance circuit in this example.
　インダクターＬは、Ｌｒヘンリーのインダクタンスを有するインダクターである。インダクターＬは、例えば、コイルである。なお、インダクターＬは、コイルに代えて、他のインダクターであってもよい。
　第３キャパシターＣ３は、静電容量が２×Ｃｒファラドのキャパシターである。ここで、当該Ｃｒファラドに乗算されている係数である２は、後述するハミルトニアンの表式を簡単にするための係数である。
　第４キャパシターＣ４は、静電容量が第３キャパシターＣ３の静電容量と同じキャパシターである。 The inductor L is an inductor having an inductance of L r Henry. The inductor L is, for example, a coil. The inductor L may be another inductor instead of the coil.
The third capacitor C3 is the capacitance is a capacitor of 2 × C r farads. Here, 2 the are C r Farad coefficients are multiplied is a factor in order to simplify the expression for Hamiltonian described later.
The fourth capacitor C4 is a capacitor having the same capacitance as that of the third capacitor C3.
　電源ＰＷは、第１共振回路ＲＣ１と第２共振回路ＲＣ２とのそれぞれに予め決められた周波数の交流電圧を供給する電源である。当該予め決められた周波数は、第１共振回路ＲＣ１と第２共振回路ＲＣ２とのうちの少なくとも一方の共振周波数であり、この一例において、マイクロ波の周波数帯に含まれる周波数である。なお、当該予め決められた周波数は、マイクロ波の周波数帯に含まれる周波数に代えて、他の周波数帯に含まれる周波数であってもよい。以下では、一例として、当該周波数が第１共振回路ＲＣ１の共振周波数である場合について説明する。 The power source PW is a power source that supplies an AC voltage having a predetermined frequency to each of the first resonance circuit RC1 and the second resonance circuit RC2. The predetermined frequency is a resonance frequency of at least one of the first resonance circuit RC1 and the second resonance circuit RC2, and in this example, is a frequency included in a microwave frequency band. The predetermined frequency may be a frequency included in another frequency band instead of the frequency included in the microwave frequency band. Below, the case where the said frequency is the resonant frequency of 1st resonant circuit RC1 is demonstrated as an example.
　ここで、制御回路１において、第１キャパシターＣ１と第０ジョセフソン接合素子Ｊ０との間と第１接点Ｐ１とが接続され、第０ジョセフソン接合素子Ｊ０と第２キャパシターＣ２との間と第３接点Ｐ３とが接続されている。また、制御回路１において、インダクターＬと第３キャパシターＣ３との間と第２接点Ｐ２とが接続され、第４キャパシターＣ４とインダクターＬとの間と第４接点Ｐ４とが接続されている。また、制御回路１において、電源ＰＷが有する２つの端子のうちの一方である第１端子Ｔ１と、第１キャパシターＣ１と第２キャパシターＣ２との間とが接続され、電源ＰＷが有する２つの端子のうちの第１端子Ｔ１と異なる第２端子Ｔ２と、第３キャパシターＣ３と第４キャパシターＣ４との間とが接続されている。また、第１共振回路ＲＣ１と第２共振回路ＲＣ２のグラウンド電位は、互いに同じである。 Here, in the control circuit 1, the first contact P1 is connected between the first capacitor C1 and the 0th Josephson junction element J0, and the first contact P1 is connected between the 0th Josephson junction element J0 and the second capacitor C2. Three contacts P3 are connected. Further, in the control circuit 1, the second contact P2 is connected between the inductor L and the third capacitor C3, and the fourth contact P4 is connected between the fourth capacitor C4 and the inductor L. Further, in the control circuit 1, the first terminal T1, which is one of the two terminals of the power supply PW, is connected between the first capacitor C1 and the second capacitor C2, and the two terminals of the power supply PW are connected. Are connected to a second terminal T2 different from the first terminal T1, and between the third capacitor C3 and the fourth capacitor C4. The ground potentials of the first resonance circuit RC1 and the second resonance circuit RC2 are the same.
　＜制御回路の動作＞
　以下、制御回路１の動作について説明する。なお、以下では、すべてのジョセフソン接合素子が超伝導状態である場合について説明する。 <Operation of control circuit>
Hereinafter, the operation of the control circuit 1 will be described. In the following, a case where all Josephson junction elements are in a superconducting state will be described.
　回路量子電磁力学に基づく制御回路１のハミルトニアンは、第１接点Ｐ１における電位の時間積分によって表される位相である第１位相φ１と、第２接点Ｐ２における電位の時間積分によって表される位相である第２位相φ２と、第３接点Ｐ３における電位の時間積分によって表される位相である第３位相φ３と、第４接点Ｐ４における電位の時間積分によって表される位相である第４位相φ４とによって、以下の式（１）～式（５）のように表される。 The Hamiltonian of the control circuit 1 based on circuit quantum electrodynamics has a first phase φ 1 that is a phase expressed by time integration of the potential at the first contact P1 and a phase expressed by time integration of the potential at the second contact P2. a second phase phi 2 is a third phase phi 3 is a phase represented by the time integral of the potential of the third contact P3, the a phase represented by the time integral of the potential at the fourth contact point P4 4 by the phase phi 4, it is represented by the following formula (1) to (5).
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000003
Figure JPOXMLDOC01-appb-M000003
Figure JPOXMLDOC01-appb-M000004
Figure JPOXMLDOC01-appb-M000004
Figure JPOXMLDOC01-appb-M000005
Figure JPOXMLDOC01-appb-M000005
　位相φＷと、位相φｑと、位相φｒと、位相φＺとのそれぞれは、第１位相φ１と、第２位相φ２と、第３位相φ３と、第４位相φ４とのそれぞれの線形結合によって作り出せる４つの線形独立な変数（自由度）のそれぞれを表す。なお、位相φＷは、本実施形態に係る制御回路１の動作と無関係な自由度であるため、上記の式（１）には表れていない。
Φ０は、磁束量子ｈ／（２e）を表す。ここで、ｈは、プランク定数を表し、ｅは、電荷素量を表している。また、ｑｑは、第１キャパシターＣ１及び第２キャパシターＣ２に蓄えられた電荷を表す。また、ｑｒは、第３キャパシターＣ３及び第４キャパシターＣ４に蓄えられた電荷を表す。ｑＺは、電源ＰＷにより交流電圧が第１共振回路ＲＣ１及び第２共振回路ＲＣ２のそれぞれに供給された場合において変調回路ＭＣに蓄えられる電荷である。すなわち、変調回路ＭＣは、静電容量を有するキャパシターとしても振る舞う。これは、前述の第１ジョセフソン接合素子Ｊ１～第４ジョセフソン接合素子Ｊ４のそれぞれが静電容量を有するためである。なお、上記の式（１）における「＾」が直上に付された変数は、当該変数が演算子であることを表している。 And phase phi W, and the phase phi q, the phase phi r, each of the phase phi Z, the first phase phi 1, a second phase phi 2, a third phase phi 3, and the fourth phase phi 4 Represents each of the four linearly independent variables (degrees of freedom) that can be created by each linear combination. Note that the phase φ W is a degree of freedom unrelated to the operation of the control circuit 1 according to the present embodiment, and thus does not appear in the above equation (1).
Φ 0 represents the magnetic flux quantum h / (2e). Here, h represents the Planck constant, and e represents the elementary charge. Q q represents the charge stored in the first capacitor C1 and the second capacitor C2. Moreover, qr represents the electric charge stored in the 3rd capacitor C3 and the 4th capacitor C4. q Z is a charge stored in the modulation circuit MC in case the AC voltage by the power supply PW is supplied to each of the first resonant circuit RC1 and the second resonant circuit RC2. That is, the modulation circuit MC also behaves as a capacitor having a capacitance. This is because each of the first Josephson junction element J1 to the fourth Josephson junction element J4 has a capacitance. Note that a variable with “^” immediately above in the above formula (1) indicates that the variable is an operator.
　上記の式（１）における第１項及び第２項は、第２共振回路ＲＣ２の共振を表す仮想的な調和振動子に関するハミルトニアンを位相φｒによって表した項である。また、当該式（１）における第３項及び第４項は、第１共振回路ＲＣ１が表す超伝導量子ビットが有する２つの量子状態（すなわち、|０〉と|１〉）を表す仮想的なスピンに関するハミルトニアンを位相φｑによって表した項である。当該スピンは、独立な２つの状態を取るスピンである。なお、以下の説明において登場するスピンは、すべて独立な２つの状態を取るスピンのことを意味する。当該式（１）における第５項は、変調回路ＭＣのエネルギーを表すハミルトニアンである。当該式（１）における第６項は、当該調和振動子と当該スピンとの間の相互作用を表す相互作用項である。図６に示したように、制御回路１が図１に示した構成である場合、当該相互作用項である当該第６項は、位相φｒ、位相φｑ、位相φＺについての非線形関数として表される。また、当該相互作用項が表す相互作用の大きさは、第１ジョセフソン接合素子Ｊ１～第４ジョセフソン接合素子Ｊ４のそれぞれが有するジョセフソンエネルギーを大きくすることにより、大きくすることができる。 The first and second terms in the above equation (1) is a term representing the Hamiltonian regarding virtual harmonic oscillator which represents the resonance of the second resonant circuit RC2 by the phase phi r. In addition, the third term and the fourth term in the formula (1) represent virtual states representing two quantum states (that is, | 0> and | 1>) included in the superconducting qubit represented by the first resonance circuit RC1. the Hamiltonian relates to a spin is a term representing the phase phi q. The spin is a spin that takes two independent states. Note that the spins appearing in the following description mean spins that take two independent states. The fifth term in the formula (1) is a Hamiltonian representing the energy of the modulation circuit MC. The sixth term in the equation (1) is an interaction term representing an interaction between the harmonic oscillator and the spin. As shown in FIG. 6, when the control circuit 1 has the configuration shown in FIG. 1, the sixth term as the interaction term is a nonlinear function with respect to the phase φ r , the phase φ q , and the phase φ Z. expressed. The magnitude of the interaction represented by the interaction term can be increased by increasing the Josephson energy of each of the first Josephson junction element J1 to the fourth Josephson junction element J4.
　ここで、図２は、位相φＷ、位相φｑ、位相φｒ、位相φＺのそれぞれが０ではない値となる場合において、第１接点Ｐ１、第２接点Ｐ２、第３接点Ｐ３、第４接点Ｐ４のそれぞれにおける電位の組み合わせのうちの特徴的な組み合わせの一例を示した図である。位相φＷが０ではない値を取る場合、あるタイミングにおける第１接点Ｐ１、第２接点Ｐ２、第３接点Ｐ３、第４接点Ｐ４のそれぞれにおける電位は、互いに大きさが同じ正の値となることができなければならない。しかし、制御回路１の構造から、当該電位は、互いに大きさが同じ正の値となることができない。このため、位相φＷは、前述した通り、非物理的な自由度である。図２に含まれる４つの図のうちＷによって示された図は、当該場合における第１接点Ｐ１、第２接点Ｐ２、第３接点Ｐ３、第４接点Ｐ４のそれぞれにおける電位が互いに大きさが同じ正の値となっている場合を示している。すなわち、当該図における「＋」は、正の値の電位を示している。また、当該図における「１」は、第１接点Ｐ１を示し、当該図における「２」は、第２接点Ｐ２を示し、当該図における「３」は、第３接点Ｐ３を示し、当該図における「４」は、第４接点Ｐ４を示している。 Here, FIG. 2 shows that the first contact P1, the second contact P2, the third contact P3, the first contact P1, the second contact P2, the third contact P3, when the phase φ W , the phase φ q , the phase φ r , and the phase φ Z are non-zero values. It is the figure which showed an example of the characteristic combination among the combinations of the electric potential in each of 4 contacts P4. If the phase phi W takes a value that is not zero, the first contact point P1 at a certain timing, the second contact P2, third contact P3, the potential at each of the fourth contacts P4, the size is the same positive value to each other It must be possible. However, due to the structure of the control circuit 1, the potentials cannot be positive values having the same magnitude. Therefore, the phase φ W is a non-physical degree of freedom as described above. Of the four diagrams included in FIG. 2, the diagram indicated by W indicates that the potentials at the first contact P1, the second contact P2, the third contact P3, and the fourth contact P4 in this case are the same in magnitude. The case where it is a positive value is shown. That is, “+” in the figure indicates a positive potential. Also, “1” in the figure indicates the first contact P1, “2” in the figure indicates the second contact P2, and “3” in the figure indicates the third contact P3. “4” indicates the fourth contact P4.
　また、位相φｑ及び位相φｒが０ではない値を取る場合、あるタイミングにおける第２接点Ｐ２における電位と第４接点Ｐ４における電位との両方が０となり、当該タイミングにおける第１接点Ｐ１における電位と第３接点Ｐ３における電位とが互いに大きさが同じで正負が逆の値となることができなければならない。Ｘによって示された図は、第２接点Ｐ２における電位と第４接点Ｐ４における電位との両方が０であり、当該タイミングにおける第１接点Ｐ１における電位と第３接点Ｐ３における電位とが互いに大きさが同じで正負が逆の値である場合を示している。当該図における「＋」は、正の値の電位を示し、当該図における「－」は、「＋」によって示された電位の大きさと同じ大きさであり符号が逆の電位を示し、当該図における「０」は、０の電位を示している。また、当該図における「１」は、第１接点Ｐ１を示し、当該図における「２」は、第２接点Ｐ２を示し、当該図における「３」は、第３接点Ｐ３を示し、当該図における「４」は、第４接点Ｐ４を示している。また、位相φｑ及び位相φｒが０ではない値を取る場合、あるタイミングにおける第１接点Ｐ１における電位と第３接点Ｐ３における電位との両方が０となり、当該タイミングにおける第２接点Ｐ２における電位と第４接点Ｐ４における電位とが互いに大きさが同じで正負が逆の値となることができなければならない。Ｙによって示された図は、第１接点Ｐ１における電位と第３接点Ｐ３における電位との両方が０であり、当該タイミングにおける第２接点Ｐ２における電位と第４接点Ｐ４における電位とが互いに大きさが同じで正負が逆の値である場合を示している。当該図における「＋」は、正の値の電位を示し、当該図における「－」は、「＋」によって示された電位の大きさと同じ大きさであり符号が逆の電位を示し、当該図における「０」は、０の電位を示している。また、当該図における「１」は、第１接点Ｐ１を示し、当該図における「２」は、第２接点Ｐ２を示し、当該図における「３」は、第３接点Ｐ３を示し、当該図における「４」は、第４接点Ｐ４を示している。 Further, when the phase φ q and the phase φ r have non-zero values, both the potential at the second contact P2 and the potential at the fourth contact P4 at a certain timing are 0, and the potential at the first contact P1 at the timing. And the potential at the third contact P3 must be able to have the same magnitude and opposite values. In the figure indicated by X, both the potential at the second contact P2 and the potential at the fourth contact P4 are 0, and the potential at the first contact P1 and the potential at the third contact P3 at the timing are mutually equal. Is the same, and the sign is opposite. “+” In the figure indicates a positive potential, and “−” in the figure indicates a potential having the same magnitude as that of the potential indicated by “+” and having the opposite sign. “0” in the symbol indicates a potential of 0. Also, “1” in the figure indicates the first contact P1, “2” in the figure indicates the second contact P2, and “3” in the figure indicates the third contact P3. “4” indicates the fourth contact P4. The phase phi if q and the phase phi r takes a value other than 0, next both are 0 and the potential of the potential and the third contact P3 of the first contact point P1 at a certain timing, the potential at the second contact point P2 at the timing And the potential at the fourth contact P4 should be the same in magnitude and opposite in value. In the figure indicated by Y, both the potential at the first contact P1 and the potential at the third contact P3 are 0, and the potential at the second contact P2 and the potential at the fourth contact P4 at the timing are mutually equal. Is the same, and the sign is opposite. “+” In the figure indicates a positive potential, and “−” in the figure indicates a potential having the same magnitude as that of the potential indicated by “+” and having the opposite sign. “0” in the symbol indicates a potential of 0. Also, “1” in the figure indicates the first contact P1, “2” in the figure indicates the second contact P2, and “3” in the figure indicates the third contact P3. “4” indicates the fourth contact P4.
　また、位相φＺが０ではない値を取る場合、あるタイミングにおける第１接点Ｐ１における電位と第３接点Ｐ３における電位との両方が正の値となり、当該タイミングにおける第２接点Ｐ２における電位と第４接点Ｐ４における電位との両方が当該正の値と大きさが同じ値で符号が逆の値となることができなければならない。Ｚによって示された図は、第１接点Ｐ１における電位と第３接点Ｐ３における電位との両方が正の値であり、第２接点Ｐ２における電位と第４接点Ｐ４における電位との両方が当該正の値と大きさが同じ値で符号が逆の値である場合を示している。当該図における「＋」は、正の値の電位を示し、当該図における「－」は、「＋」によって示された電位の大きさと同じ大きさであり符号が逆の電位を示している。また、当該図における「１」は、第１接点Ｐ１を示し、当該図における「２」は、第２接点Ｐ２を示し、当該図における「３」は、第３接点Ｐ３を示し、当該図における「４」は、第４接点Ｐ４を示している。 Also, when taking the values phase phi Z is not 0, both the potential at the potential and the third contact point P3 of the first contact point P1 at a certain timing becomes a positive value, and the potential at the second contact point P2 at this timing the Both of the potentials at the four contacts P4 must be the same value as the positive value and can have opposite signs. In the figure indicated by Z, both the potential at the first contact P1 and the potential at the third contact P3 are positive values, and both the potential at the second contact P2 and the potential at the fourth contact P4 are positive. The case where the value is the same as the value of and the value is the opposite sign is shown. In the figure, “+” indicates a positive potential, and “−” in the figure indicates a potential having the same magnitude as the potential indicated by “+” and having the opposite sign. Also, “1” in the figure indicates the first contact P1, “2” in the figure indicates the second contact P2, and “3” in the figure indicates the third contact P3. “4” indicates the fourth contact P4.
　さて、電源ＰＷのスイッチがオフの場合、制御回路１の構造（が有する対称性）によって、あるタイミングにおける第１接点Ｐ１における電位と第３接点Ｐ３における電位とは、両方が０、又は互いに大きさが同じで正負が逆の値となる。また、当該場合、制御回路１の構造（が有する対称性）によって、あるタイミングにおける第２接点Ｐ２における電位と第４接点Ｐ４における電位とは、両方が０、又は互いに大きさが同じで正負が逆の値となる。このため、位相φＺは、当該場合において常に０であり、第１共振回路ＲＣ１と第２共振回路ＲＣ２とは、電気的に結合することができない。その結果、当該場合、第１共振回路ＲＣ１と第２共振回路ＲＣ２のそれぞれは、互いに独立に（互いに無関係に）共振する。これは、当該場合において前述の第６項（上記の相互作用項）が定数項となることとして上記の式（１）に示したハミルトニアンに反映されており、第２共振回路ＲＣ２の共振を表す仮想的な調和振動子と、第１共振回路ＲＣ１によって構成された超伝導量子ビットが有する２つの量子状態（すなわち、|０〉と|１〉）を表す仮想的なスピンとの間の相互作用が消失していること（当該相互作用がオフの状態であること）を意味している。また、これは、第１ジョセフソン接合素子Ｊ１～第４ジョセフソン接合素子Ｊ４のそれぞれが有するジョセフソンエネルギーの大きさと無関係に起こる現象である。このため、当該相互作用の強さを強くしたとしても、電源ＰＷのスイッチをオフにすることにより、制御回路１では、当該相互作用をオフの状態にすることができる。なお、電源ＰＷのスイッチがオフの場合とは、電源ＰＷにより第１共振回路ＲＣ１と第２共振回路ＲＣ２との間に差動交流電圧が供給されていない場合のことである。 When the switch of the power supply PW is OFF, the potential at the first contact P1 and the potential at the third contact P3 at a certain timing are both 0 or large due to the structure of the control circuit 1 (the symmetry that the control circuit 1 has). The values are the same and the values are opposite. In this case, the potential of the second contact P2 and the potential of the fourth contact P4 at a certain timing are both 0 or the same in magnitude and positive / negative depending on the structure of the control circuit 1. The opposite value. Therefore, the phase phi Z is always 0 when the, first resonant circuit RC1 and the second resonant circuit RC2, can not be electrically coupled. As a result, in this case, the first resonance circuit RC1 and the second resonance circuit RC2 resonate independently of each other (independently of each other). This is reflected in the Hamiltonian shown in the above equation (1) as the aforementioned sixth term (the above interaction term) becomes a constant term in this case, and represents the resonance of the second resonance circuit RC2. Interaction between a virtual harmonic oscillator and a virtual spin representing two quantum states (ie, | 0> and | 1>) of a superconducting qubit formed by the first resonance circuit RC1 Has disappeared (the interaction is in an off state). This is a phenomenon that occurs regardless of the magnitude of the Josephson energy of each of the first Josephson junction element J1 to the fourth Josephson junction element J4. For this reason, even if the strength of the interaction is increased, the interaction can be turned off in the control circuit 1 by turning off the switch of the power source PW. Note that the case where the switch of the power supply PW is off is a case where the differential AC voltage is not supplied between the first resonance circuit RC1 and the second resonance circuit RC2 by the power supply PW.
　一方、電源ＰＷのスイッチがオンの場合、あるタイミングにおいて、第１接点Ｐ１における電位と第３接点Ｐ３における電位とが正の電位となり、且つ、当該タイミングにおいて第２接点Ｐ２における電位と第４接点Ｐ４における電位とが負の電位となることができる。また、当該場合、当該タイミングとは別のタイミングにおいて、第１接点Ｐ１における電位と第３接点Ｐ３における電位とが負の電位となり、且つ、当該タイミングにおいて第２接点Ｐ２における電位と第４接点Ｐ４における電位とが正の電位となることができる。このため、位相φＺは、当該場合において常に０ではなく、０と異なる値となる場合がある。従って、当該場合、第１共振回路ＲＣ１と第２共振回路ＲＣ２とは、電気的に結合する。その結果、当該場合、第１共振回路ＲＣ１と第２共振回路ＲＣ２とのそれぞれは、互いの共振に応じて共振する。これは、当該場合において前述の第６項（上記の相互作用項）のうち位相φｒ、位相φｑ、位相φＺのそれぞれに依存する項が０ではなくなることとして上記の式（１）に示したハミルトニアンに反映されており、第２共振回路ＲＣ２の共振を表す仮想的な調和振動子が、第１共振回路ＲＣ１によって構成された超伝導量子ビットが有する２つの量子状態（すなわち、|０〉と|１〉）を表す仮想的なスピンの状態に応じた力を受けること（すなわち、当該調和振動子と当該スピンとの間の相互作用が発生していること（オンの状態であること））を意味している。また、当該相互作用の強さは、第１ジョセフソン接合素子Ｊ１～第４ジョセフソン接合素子Ｊ４のそれぞれが有するジョセフソンエネルギーを大きくするほど大きくなる。このため、制御回路１では、当該ジョセフソンエネルギーを大きくすることにより、当該相互作用の強さを強くすることができる。なお、電源ＰＷのスイッチがオンの場合とは、電源ＰＷにより第１共振回路ＲＣ１及び第２共振回路ＲＣ２のそれぞれに交流電圧が供給されている場合のことである。 On the other hand, when the switch of the power supply PW is on, the potential at the first contact P1 and the potential at the third contact P3 become positive at a certain timing, and the potential at the second contact P2 and the fourth contact at the timing. The potential at P4 can be a negative potential. In this case, at a timing different from the timing, the potential at the first contact P1 and the potential at the third contact P3 become negative, and the potential at the second contact P2 and the fourth contact P4 at the timing. The potential at can be a positive potential. Therefore, the phase phi Z is always not 0 when the, it may become 0 and different values. Therefore, in this case, the first resonance circuit RC1 and the second resonance circuit RC2 are electrically coupled. As a result, in this case, each of the first resonance circuit RC1 and the second resonance circuit RC2 resonates according to the mutual resonance. In this case, the above-mentioned sixth term (the above interaction term), in which the terms depending on the phase φ r , the phase φ q , and the phase φ Z are not 0, Reflected in the shown Hamiltonian, the virtual harmonic oscillator representing the resonance of the second resonance circuit RC2 has two quantum states (i.e., | 0) included in the superconducting qubit formed by the first resonance circuit RC1. > And | 1>) (i.e., an interaction between the harmonic oscillator and the spin occurs (the state is on). )). The strength of the interaction increases as the Josephson energy of each of the first Josephson junction element J1 to the fourth Josephson junction element J4 increases. For this reason, in the control circuit 1, the intensity of the interaction can be increased by increasing the Josephson energy. Note that the case where the switch of the power supply PW is on is a case where an AC voltage is supplied to each of the first resonance circuit RC1 and the second resonance circuit RC2 by the power supply PW.
　このように、制御回路１（すなわち、変調回路ＭＣ）は、第１位相φ１と、第２位相φ２と、第３位相φ３と、第４位相φ４とに基づいて、第１共振回路ＲＣ１と第２共振回路ＲＣ２との結合状態を変化させる。より具体的には、制御回路１は、第１位相φ１と、第２位相φ２と、第３位相φ３と、第４位相φ４とに基づいて、第１共振回路ＲＣ１と第２共振回路ＲＣ２とが結合していない状態と、第１共振回路ＲＣ１と第２共振回路ＲＣ２とが結合している状態とのいずれかに変化させる。これにより、制御回路１は、第１共振回路ＲＣ１と第２共振回路ＲＣ２の電気的な結合を切ることができる。 Thus, the control circuit 1 (i.e., the modulation circuit MC) includes a first phase phi 1, a second phase phi 2, a third phase phi 3, based on the fourth phase phi 4, first resonant The coupling state between the circuit RC1 and the second resonance circuit RC2 is changed. More specifically, the control circuit 1 includes a first phase phi 1, a second phase phi 2, a third phase phi 3, based on the fourth phase phi 4, and the first resonance circuit RC1 second The state is changed to either a state where the resonance circuit RC2 is not coupled or a state where the first resonance circuit RC1 and the second resonance circuit RC2 are coupled. Thereby, the control circuit 1 can cut | disconnect the electrical coupling of 1st resonance circuit RC1 and 2nd resonance circuit RC2.
　また、制御回路１は、第１共振回路ＲＣ１と第２共振回路ＲＣ２とのそれぞれに交流電圧を供給する電源ＰＷにより第１共振回路ＲＣ１と第２共振回路ＲＣ２とのそれぞれへの交流電圧の供給が開始された場合、第１共振回路ＲＣ１と第２共振回路ＲＣ２との結合状態を第１共振回路ＲＣ１と第２共振回路ＲＣ２とが結合している状態に変化させ、電源ＰＷにより第１共振回路ＲＣ１と第２共振回路ＲＣ２とのそれぞれへの交流電圧の供給が停止された場合、当該結合状態を第１共振回路ＲＣ１と第２共振回路ＲＣ２とが結合していない状態に変化させる。これにより、制御回路１は、第１共振回路ＲＣ１と第２共振回路ＲＣ２への電源ＰＷによる交流電圧の供給状態（すなわち、電源ＰＷのスイッチのオン／オフ）に応じて、第１共振回路と第２共振回路の結合状態を切り替えることができる。 In addition, the control circuit 1 supplies an AC voltage to each of the first resonance circuit RC1 and the second resonance circuit RC2 by a power source PW that supplies an AC voltage to each of the first resonance circuit RC1 and the second resonance circuit RC2. Is started, the coupling state between the first resonance circuit RC1 and the second resonance circuit RC2 is changed to a state in which the first resonance circuit RC1 and the second resonance circuit RC2 are coupled, and the first resonance is generated by the power supply PW. When the supply of the AC voltage to each of the circuit RC1 and the second resonance circuit RC2 is stopped, the coupling state is changed to a state where the first resonance circuit RC1 and the second resonance circuit RC2 are not coupled. Thereby, the control circuit 1 is connected to the first resonance circuit RC1 and the second resonance circuit RC2 in accordance with the supply state of the AC voltage by the power source PW (that is, on / off of the switch of the power source PW). The coupling state of the second resonance circuit can be switched.
　＜第１共振回路のエネルギーと第２共振回路のエネルギーとの関係＞
　以下、第１共振回路ＲＣ１のエネルギーと第２共振回路ＲＣ２のエネルギーとの関係について説明する。 <Relationship between energy of first resonance circuit and energy of second resonance circuit>
Hereinafter, the relationship between the energy of the first resonance circuit RC1 and the energy of the second resonance circuit RC2 will be described.
　電源ＰＷのスイッチがオフの場合、前述したように、第１共振回路ＲＣ１と第２共振回路ＲＣ２とは、電気的に結合することができない。当該場合、制御回路１では、第１共振回路ＲＣ１のエネルギーと、第２共振回路ＲＣ２のエネルギーとが独立に変化する。当該場合、制御回路１に外部から電気的なエネルギーが供給されていないため、熱エネルギーとしてエネルギーが損失してしまうことを無視すれば、制御回路１全体のエネルギーは変化しない（保存される）。このため、当該場合、制御回路１では、第１共振回路ＲＣ１の量子状態（より具体的には、第１共振回路ＲＣ１の共振を表す調和振動子の量子状態）と、第２共振回路ＲＣ２の量子状態（より具体的には、第２共振回路ＲＣ２により構成された超伝導量子ビットの量子状態）とが独立に変化する。すなわち、当該場合、制御回路１では、第１共振回路ＲＣ１と第２共振回路ＲＣ２との間の相互作用が消失している（すなわち、当該相互作用がオフの状態である）。 When the switch of the power supply PW is off, as described above, the first resonance circuit RC1 and the second resonance circuit RC2 cannot be electrically coupled. In this case, in the control circuit 1, the energy of the first resonance circuit RC1 and the energy of the second resonance circuit RC2 change independently. In this case, since no electrical energy is supplied to the control circuit 1 from the outside, the energy of the entire control circuit 1 does not change (is stored) if the loss of energy as thermal energy is ignored. For this reason, in this case, in the control circuit 1, the quantum state of the first resonance circuit RC1 (more specifically, the quantum state of the harmonic oscillator representing the resonance of the first resonance circuit RC1) and the second resonance circuit RC2 The quantum state (more specifically, the quantum state of the superconducting qubit configured by the second resonance circuit RC2) changes independently. That is, in this case, in the control circuit 1, the interaction between the first resonance circuit RC1 and the second resonance circuit RC2 has disappeared (that is, the interaction is off).
　一方、電源ＰＷのスイッチがオンの場合、第１共振回路ＲＣ１と第２共振回路ＲＣ２とは、電気的に結合する。当該場合、制御回路１では、第１共振回路ＲＣ１のエネルギーの変化に応じて第２共振回路ＲＣ２のエネルギーが非線形（上記で説明した例では、三角関数的）に変化する。より具体的には、制御回路１は、第１位相φ１と、第２位相φ２と、第３位相φ３と、第４位相φ４とに基づいて、第１共振回路ＲＣ１のエネルギーの変化に応じて第２共振回路ＲＣ２のエネルギーが非線形に変化する。このため、当該場合、制御回路１では、第１共振回路ＲＣ１の量子状態（より具体的には、第１共振回路ＲＣ１の共振を表す調和振動子の量子状態）の変化に応じて、第２共振回路ＲＣ２の量子状態（より具体的には、第２共振回路ＲＣ２により構成された超伝導量子ビットの量子状態）が変化する。すなわち、当該場合、制御回路１では、第１共振回路ＲＣ１と第２共振回路ＲＣ２との間に相互作用が発生している（すなわち、当該相互作用がオンの状態である）。なお、第１共振回路ＲＣ１のエネルギーの変化に応じた第２共振回路ＲＣ２のエネルギーの変化と、第１共振回路ＲＣ１の量子状態の変化に応じた第２共振回路ＲＣ２の量子状態の変化とは、必ずしも一対一に対応づくものではない。 On the other hand, when the switch of the power supply PW is on, the first resonance circuit RC1 and the second resonance circuit RC2 are electrically coupled. In this case, in the control circuit 1, the energy of the second resonance circuit RC2 changes nonlinearly (trigonometrically in the example described above) in accordance with the change in energy of the first resonance circuit RC1. More specifically, the control circuit 1 includes a first phase phi 1, a second phase phi 2, a third phase phi 3, based on the fourth phase phi 4, the energy of the first resonant circuit RC1 The energy of the second resonance circuit RC2 changes nonlinearly according to the change. Therefore, in this case, the control circuit 1 changes the second state according to the change in the quantum state of the first resonance circuit RC1 (more specifically, the quantum state of the harmonic oscillator representing the resonance of the first resonance circuit RC1). The quantum state of the resonant circuit RC2 (more specifically, the quantum state of the superconducting qubit formed by the second resonant circuit RC2) changes. That is, in this case, in the control circuit 1, an interaction occurs between the first resonance circuit RC1 and the second resonance circuit RC2 (that is, the interaction is in an on state). Note that a change in energy of the second resonance circuit RC2 according to a change in energy of the first resonance circuit RC1 and a change in quantum state of the second resonance circuit RC2 according to a change in quantum state of the first resonance circuit RC1. However, it does not necessarily correspond to one to one.
　このように、制御回路１では、電源ＰＷのスイッチのオン／オフに応じて、第１共振回路ＲＣ１と第２共振回路ＲＣ２との間の相互作用のオン／オフ（すなわち、発生／消失）を切り替えることができる。 Thus, in the control circuit 1, the interaction between the first resonance circuit RC1 and the second resonance circuit RC2 is turned on / off (that is, generated / disappeared) in accordance with the on / off of the switch of the power supply PW. Can be switched.
　＜制御回路の集積化と超伝導量子ビット間の相互作用＞
　以下、図３及び図４を参照し、制御回路１の集積化と超伝導量子ビット間の相互作用について説明する。 <Integration of control circuit and interaction between superconducting qubits>
Hereinafter, the integration of the control circuit 1 and the interaction between the superconducting qubits will be described with reference to FIGS.
　制御回路１が集積された集積回路を作成する作成者は、第１共振回路ＲＣ１における第０ジョセフソン接合素子Ｊ０と、第２共振回路ＲＣ２におけるインダクターＬとのうち少なくとも一方を他の制御回路１と共有させることにより、制御回路１を二次元的又は三次元的に集積回路化することができる。 A creator who creates an integrated circuit in which the control circuit 1 is integrated has at least one of the 0th Josephson junction element J0 in the first resonance circuit RC1 and the inductor L in the second resonance circuit RC2 as another control circuit 1. The control circuit 1 can be integrated into a two-dimensional or three-dimensional integrated circuit.
　図３は、制御回路１を二次元的に集積化する方法の概念を説明するための図である。図３では、二次元正方格子が有する接点それぞれの位置に印ＭＫ１が配置されている。また、図３では、当該二次元正方格子上の点であって印ＭＫ１と印ＭＫ１との中点それぞれの位置に印ＭＫ２が配置されている。ここで、図３における複数の印ＭＫ１のそれぞれは、前述の第１共振回路ＲＣ１を示している。また、図３における複数の印ＭＫ２のそれぞれは、前述の第２共振回路ＲＣ２を示している。また、図３において印ＭＫ１と印ＭＫ２との間を繋ぐ線は、印ＭＫ１が表す第１共振回路ＲＣ１と印ＭＫ２が表す第２共振回路ＲＣ２とのそれぞれに対して図１に示したように接続された変調回路ＭＣ及び電源ＰＷを示している。また、図３において印ＭＫ３は、各第１共振回路ＲＣ１に接続された回路であり、第１共振回路ＲＣ１のそれぞれが構成する超伝導量子ビットの量子状態を読み出す読出回路である。第１共振回路ＲＣ１のそれぞれに接続された読出回路は、第１共振回路ＲＣ１が構成する超伝導量子ビットの量子状態を読み出すことが可能であれば、既知の回路であってもよく、これから開発される回路であってもよい。例えば、第１共振回路ＲＣ１のそれぞれに接続された読出回路には、変調回路ＭＣを介して当該第１共振回路ＲＣ１に接続された第２共振回路ＲＣ２が用いられてもよい。この場合、当該第２共振回路ＲＣ２は、当該量子状態を読み出す読出回路を備える。なお、当該読出回路により当該量子状態を読み出す場合、当該第２共振回路ＲＣ２には、マイクロ波パルスの反射係数測定が行われる場合がある。 FIG. 3 is a diagram for explaining the concept of a method for integrating the control circuit 1 two-dimensionally. In FIG. 3, a mark MK1 is arranged at each contact point of the two-dimensional square lattice. Further, in FIG. 3, marks MK2 are arranged at positions on the two-dimensional square lattice at the midpoints of the marks MK1 and MK1. Here, each of the plurality of marks MK1 in FIG. 3 represents the first resonance circuit RC1 described above. Further, each of the plurality of marks MK2 in FIG. 3 indicates the above-described second resonance circuit RC2. Further, in FIG. 3, the line connecting the mark MK1 and the mark MK2 is as shown in FIG. 1 for each of the first resonance circuit RC1 represented by the mark MK1 and the second resonance circuit RC2 represented by the mark MK2. The connected modulation circuit MC and power supply PW are shown. In FIG. 3, a mark MK3 is a circuit connected to each first resonance circuit RC1, and is a readout circuit that reads the quantum state of the superconducting qubits formed by each of the first resonance circuits RC1. The readout circuit connected to each of the first resonance circuits RC1 may be a known circuit as long as it can read out the quantum state of the superconducting qubit formed by the first resonance circuit RC1, and will be developed from now on. It may be a circuit. For example, the second resonance circuit RC2 connected to the first resonance circuit RC1 via the modulation circuit MC may be used for the readout circuit connected to each of the first resonance circuits RC1. In this case, the second resonance circuit RC2 includes a readout circuit that reads the quantum state. Note that when the quantum state is read out by the readout circuit, the reflection coefficient measurement of the microwave pulse may be performed in the second resonance circuit RC2.
　このように複数の制御回路１同士を、第１共振回路ＲＣ１と第２共振回路ＲＣ２の少なくとも一方を共有させて接続させることにより、複数の制御回路１が集積された集積回路を作成する作成者は、当該集積回路を作成することができる。すなわち、当該作成者は、変調回路ＭＣを介して複数の第１共振回路ＲＣ１と複数の第２共振回路ＲＣ２とを交互に接続し、第１共振回路ＲＣ１と第２共振回路ＲＣ２とを二次元的に集積回路化することができる。 A creator who creates an integrated circuit in which a plurality of control circuits 1 are integrated by connecting at least one of the first resonance circuit RC1 and the second resonance circuit RC2 to each other by connecting the plurality of control circuits 1 to each other. Can create the integrated circuit. That is, the creator alternately connects the plurality of first resonance circuits RC1 and the plurality of second resonance circuits RC2 via the modulation circuit MC, and connects the first resonance circuit RC1 and the second resonance circuit RC2 two-dimensionally. Thus, an integrated circuit can be obtained.
　図４は、図３に示した概念に基づいて複数の制御回路１を集積させた集積回路の一例を示す図である。例えば、図４に示した集積回路に含まれる部分回路ＰＣ１は、第２共振回路ＲＣ２（より具体的には、インダクターＬ）を２つの制御回路１において共有させた回路である。また、図４に示した集積回路に含まれる部分回路ＰＣ２は、第１共振回路ＲＣ１（より具体的には、第０ジョセフソン接合素子Ｊ０）を２つの制御回路１において共有させた回路である。すなわち、図４では、当該集積回路が有する複数の変調回路ＭＣそれぞれが備える４つのジョセフソン接合素子（第１ジョセフソン接合素子Ｊ１～第４ジョセフソン接合素子Ｊ４）のうち、第１共振回路ＲＣ１に近い側の２つのジョセフソン接合素子がπ接合のジョセフソン接合素子であり、第２共振回路ＲＣ２に近い側の２つのジョセフソン接合素子がπ接合のジョセフソン接合素子である。なお、図１において制御回路１が有する各素子に対して付していた符号は、図４では、図が煩雑になるため、省略している。 FIG. 4 is a diagram showing an example of an integrated circuit in which a plurality of control circuits 1 are integrated based on the concept shown in FIG. For example, the partial circuit PC1 included in the integrated circuit shown in FIG. 4 is a circuit in which the two control circuits 1 share the second resonance circuit RC2 (more specifically, the inductor L). Further, the partial circuit PC2 included in the integrated circuit shown in FIG. 4 is a circuit in which the first control circuit RC1 (more specifically, the 0th Josephson junction element J0) is shared by the two control circuits 1. . That is, in FIG. 4, among the four Josephson junction elements (the first Josephson junction element J1 to the fourth Josephson junction element J4) included in each of the plurality of modulation circuits MC included in the integrated circuit, the first resonance circuit RC1. The two Josephson junction elements nearer to the second resonance circuit are π-junction Josephson junction elements, and the two Josephson junction elements closer to the second resonance circuit RC2 are π-junction Josephson junction elements. Note that the reference numerals given to the elements of the control circuit 1 in FIG. 1 are omitted in FIG. 4 because the figure becomes complicated.
　図４に示したように複数の制御回路１を集積することにより、例えば、部分回路ＰＣ１が有する２つの電源ＰＷそれぞれのスイッチをオンにした場合、部分回路ＰＣ１が有する１つの変調回路ＭＣを介して、部分回路ＰＣ１が有する２つの第１共振回路ＲＣ１のそれぞれが構成する超伝導量子ビット間において相互作用が発生する。また、部分回路ＰＣ１が有する２つの電源ＰＷのうちいずれか一方のスイッチをオフにした場合、部分回路ＰＣ１が有する２つの第１共振回路ＲＣ１のそれぞれが構成する超伝導量子ビット間における相互作用が消失する。このように、図４に示したように複数の制御回路１を集積することにより、当該複数の制御回路１を備える量子計算機は、ユーザーが所望する任意の隣り合う２つの超伝導量子ビット間の相互作用のオン／オフを切り替えることができる。その結果、当該量子計算機は、当該相互作用をオフにした際（すなわち、当該スイッチをオフにした際）、第１共振回路ＲＣ１と第２共振回路ＲＣ２との間の電気的な結合を残すことなく切ることができ（すなわち、第１共振回路ＲＣ１と第２共振回路ＲＣ２との間の相互作用を残すことなく切ることができ）、第１共振回路ＲＣ１と第２共振回路ＲＣ２との間の電気的な結合が切れずに残った場合に発生する誤りであって量子計算における誤りの発生を抑制することができる。また、当該量子計算機は、当該誤りが他の超伝導量子ビットを構成する共振回路に伝播してしまうことを抑制することができる。 By integrating the plurality of control circuits 1 as shown in FIG. 4, for example, when each of the two power supply PWs included in the partial circuit PC1 is turned on, the partial circuit PC1 includes a single modulation circuit MC. Thus, an interaction occurs between the superconducting qubits formed by each of the two first resonance circuits RC1 included in the partial circuit PC1. In addition, when any one of the two power sources PW included in the partial circuit PC1 is turned off, the interaction between the superconducting qubits formed by the two first resonance circuits RC1 included in the partial circuit PC1 is caused. Disappear. As described above, by integrating a plurality of control circuits 1 as shown in FIG. 4, a quantum computer including the plurality of control circuits 1 can be used between any two adjacent superconducting qubits desired by the user. The interaction can be switched on / off. As a result, the quantum computer leaves an electrical coupling between the first resonance circuit RC1 and the second resonance circuit RC2 when the interaction is turned off (that is, when the switch is turned off). (Ie, without leaving an interaction between the first resonant circuit RC1 and the second resonant circuit RC2), and between the first resonant circuit RC1 and the second resonant circuit RC2. It is an error that occurs when the electrical coupling remains without being broken, and the occurrence of an error in quantum computation can be suppressed. In addition, the quantum computer can suppress the error from propagating to the resonance circuit constituting another superconducting qubit.
　なお、複数の制御回路１は、図４に示したように二次元的に集積される構成に代えて、三次元的に集積される構成であってもよい。この場合、ある二次元平面上に集積された複数の制御回路１のそれぞれは、例えば、当該二次元平面と直交する方向に重なる他の二次元平面上に集積された複数の制御回路１のそれぞれとビアを用いて電気的に接続される。 Note that the plurality of control circuits 1 may have a three-dimensionally integrated configuration instead of the two-dimensionally integrated configuration shown in FIG. In this case, each of the plurality of control circuits 1 integrated on a certain two-dimensional plane is, for example, each of the plurality of control circuits 1 integrated on another two-dimensional plane overlapping in the direction orthogonal to the two-dimensional plane. And are electrically connected using vias.
　また、上記において説明した第２共振回路ＲＣ２は、ＬＣ共振回路に代えて、他の共振回路であってもよい。当該他の共振回路は、既知の共振回路であってもよく、これから開発される共振回路であってもよい。また、第２共振回路ＲＣ２は、ＬＣ共振回路に代えて、空洞共振器を用いた回路であってもよい。この場合、第２共振回路ＲＣ２では、例えば、空洞共振器を構成する導体中に誘起される電流がＬＣ共振回路を流れる電流の代わりに用いられる。 Further, the second resonance circuit RC2 described above may be another resonance circuit instead of the LC resonance circuit. The other resonance circuit may be a known resonance circuit or a resonance circuit to be developed in the future. Further, the second resonance circuit RC2 may be a circuit using a cavity resonator instead of the LC resonance circuit. In this case, in the second resonance circuit RC2, for example, a current induced in the conductor constituting the cavity resonator is used instead of the current flowing through the LC resonance circuit.
　また、上記において説明した第１共振回路ＲＣ１は、超伝導量子ビットを構成する量子ビット回路に代えて、第２共振回路ＲＣ２のような共振回路（例えば、ＬＣ共振回路）であってもよい。この場合、制御回路１を備える情報処理装置は、制御回路１により、２つの調和振動子のそれぞれを構成する２つの共振回路の間の量子状態を制御することができる。当該情報処理装置は、例えば、一方の共振回路を量子メモリとし、当該量子メモリに他方の量子状態（量子情報）を記憶させることができる。このため、当該情報処理装置は、李当該量子メモリに記憶された量子状態を読み出すこともできる。 Further, the first resonance circuit RC1 described above may be a resonance circuit (for example, an LC resonance circuit) like the second resonance circuit RC2 instead of the qubit circuit constituting the superconducting qubit. In this case, the information processing apparatus including the control circuit 1 can control the quantum state between the two resonance circuits constituting each of the two harmonic oscillators by the control circuit 1. For example, the information processing apparatus can use one resonance circuit as a quantum memory and store the other quantum state (quantum information) in the quantum memory. For this reason, the information processing apparatus can also read the quantum state stored in the quantum memory.
　また、２つの調和振動子のそれぞれを構成する２つの共振回路を第１共振回路ＲＣ１及び第２共振回路ＲＣ２として有する制御回路１ａと、２つの超伝導量子ビットのそれぞれを構成する２つの共振回路を第１共振回路ＲＣ１及び第２共振回路ＲＣ２として有する制御回路１ｂとが組み合わされた回路は、量子計算機、量子計算機以外の情報処理装置の少なくとも一方に備えられる構成であってもよい。 In addition, a control circuit 1a having two resonance circuits constituting the two harmonic oscillators as the first resonance circuit RC1 and the second resonance circuit RC2, and two resonance circuits constituting the two superconducting qubits, respectively. The circuit combined with the control circuit 1b having the first resonance circuit RC1 and the second resonance circuit RC2 may be provided in at least one of a quantum computer and an information processing device other than the quantum computer.
　＜実施形態の変形例１＞
　以下、図５及び図６を参照し、実施形態の変形例１について説明する。なお、実施形態の変形例１では、実施形態と同様な構成部に対して同じ符号を付して説明を省略する。 <Modification 1 of Embodiment>
Hereinafter, Modification 1 of the embodiment will be described with reference to FIGS. 5 and 6. In addition, in the modification 1 of embodiment, the same code | symbol is attached | subjected with respect to the component similar to embodiment, and description is abbreviate | omitted.
　実施形態において説明した制御回路１は、第２共振回路ＲＣ２に代えて、以下において説明する第３共振回路ＲＣ３を備える構成であってもよい。以下では、第２共振回路ＲＣ２に代えて第３共振回路ＲＣ３を備える制御回路１を、制御回路２と称して説明する。第３共振回路ＲＣ３は、第１共振回路ＲＣ１と同様に超伝導量子ビットを構成する共振回路である。すなわち、制御回路２は、ＬＣ共振回路である第２共振回路ＲＣ２を用いることなく（図４に示したように第２共振回路ＲＣ２を介することなく）、制御回路２が備える２つの超伝導量子ビット間の相互作用のオン／オフを切り替えることができるスイッチ回路である。 The control circuit 1 described in the embodiment may include a third resonance circuit RC3 described below instead of the second resonance circuit RC2. Hereinafter, the control circuit 1 including the third resonance circuit RC3 instead of the second resonance circuit RC2 will be described as a control circuit 2. The third resonance circuit RC3 is a resonance circuit that constitutes a superconducting qubit in the same manner as the first resonance circuit RC1. That is, the control circuit 2 does not use the second resonance circuit RC2 that is an LC resonance circuit (without passing through the second resonance circuit RC2 as shown in FIG. 4), and the two superconducting quanta included in the control circuit 2 It is a switch circuit capable of switching on / off of interaction between bits.
　まず、制御回路２の構成について説明する。図５は、実施形態の変形例１に係る制御回路２の構成の一例を示す図である。 First, the configuration of the control circuit 2 will be described. FIG. 5 is a diagram illustrating an example of the configuration of the control circuit 2 according to the first modification of the embodiment.
　制御回路２は、変調回路ＭＣと、第１共振回路ＲＣ１と、第３共振回路ＲＣ３と、電源ＰＷを備える。なお、制御回路２は、これら３つの回路及び電源ＰＷに加えて、他の回路を備える構成であってもよい。ただし、この場合、当該他の回路は、以下において説明する制御回路２が有する特徴を壊さないように制御回路２に備えられなければならない。換言すると、以下において説明する制御回路２が有する特徴を壊さなければ、制御回路２は、如何なる変更を受けてもよい。 The control circuit 2 includes a modulation circuit MC, a first resonance circuit RC1, a third resonance circuit RC3, and a power supply PW. The control circuit 2 may be configured to include other circuits in addition to these three circuits and the power supply PW. However, in this case, the other circuit must be provided in the control circuit 2 so as not to break the characteristics of the control circuit 2 described below. In other words, the control circuit 2 may be subjected to any changes as long as the characteristics of the control circuit 2 described below are not destroyed.
　第３共振回路ＲＣ３は、第２共振回路ＲＣ２におけるインダクターＬを第５ジョセフソン接合素子Ｊ５に置き換えた環状回路である。すなわち、第３共振回路ＲＣ３は、第５ジョセフソン接合素子Ｊ５と、第３キャパシターＣ３と、第４キャパシターＣ４を備える環状回路である。 The third resonance circuit RC3 is an annular circuit in which the inductor L in the second resonance circuit RC2 is replaced with a fifth Josephson junction element J5. That is, the third resonance circuit RC3 is an annular circuit including the fifth Josephson junction element J5, the third capacitor C3, and the fourth capacitor C4.
　第５ジョセフソン接合素子Ｊ５は、０接合のジョセフソン接合素子である。第５ジョセフソン接合素子Ｊ５は、第３キャパシターＣ３と第４キャパシターＣ４との間に位置する。なお、第５ジョセフソン接合素子Ｊ５は、０接合のジョセフソン接合素子に代えて、π接合のジョセフソン接合素子であってもよい。 The fifth Josephson junction element J5 is a zero junction Josephson junction element. The fifth Josephson junction element J5 is located between the third capacitor C3 and the fourth capacitor C4. The fifth Josephson junction element J5 may be a π-junction Josephson junction element instead of the 0-junction Josephson junction element.
　このように、制御回路２が第１共振回路ＲＣ１と第３共振回路ＲＣ３を備える場合、回路量子電磁力学に基づく制御回路２のハミルトニアンの構造は、上記の式（１）に示したハミルトニアンとほぼ同じ構造になる。このため、電源ＰＷのスイッチがオフの場合、位相φＺが常に０であり、制御回路２において第１共振回路ＲＣ１と第３共振回路ＲＣ３とは、電気的に結合することができない。その結果、当該場合、第１共振回路ＲＣ１と第３共振回路ＲＣ３のそれぞれは、互いに独立に（互いに無関係に）共振する。これは、第３共振回路ＲＣ３によって構成された超伝導量子ビットが有する２つの量子状態（すなわち、|０〉と|１〉）を表す仮想的なスピンと、第１共振回路ＲＣ１によって構成された超伝導量子ビットが有する２つの量子状態（すなわち、|０〉と|１〉）を表す仮想的なスピンとの間の相互作用が消失していること（当該相互作用がオフの状態であること）を意味している。また、これは、第１ジョセフソン接合素子Ｊ１～第４ジョセフソン接合素子Ｊ４のそれぞれが有するジョセフソンエネルギーの大きさと無関係に起こる現象である。このため、当該相互作用の強さを強くしたとしても、電源ＰＷのスイッチをオフにすることにより、制御回路２では、当該相互作用をオフの状態にすることができる。 As described above, when the control circuit 2 includes the first resonance circuit RC1 and the third resonance circuit RC3, the Hamiltonian structure of the control circuit 2 based on the circuit quantum electrodynamics is almost the same as the Hamiltonian represented by the above equation (1). It becomes the same structure. Therefore, when the switch of the power source PW is turned off, the phase phi Z always 0, the first resonance circuit RC1 in the control circuit 2 and the third resonant circuit RC3, can not be electrically coupled. As a result, in this case, the first resonance circuit RC1 and the third resonance circuit RC3 resonate independently of each other (independently of each other). This is configured by a virtual spin representing two quantum states (that is, | 0> and | 1>) included in the superconducting qubit configured by the third resonance circuit RC3 and the first resonance circuit RC1. The interaction between the virtual spins representing the two quantum states of the superconducting qubit (ie, | 0> and | 1>) has disappeared (the interaction must be off) ). This is a phenomenon that occurs regardless of the magnitude of the Josephson energy of each of the first Josephson junction element J1 to the fourth Josephson junction element J4. For this reason, even if the strength of the interaction is increased, the interaction can be turned off in the control circuit 2 by turning off the switch of the power source PW.
　一方、電源ＰＷのスイッチがオンの場合、第１共振回路ＲＣ１と第３共振回路ＲＣ３とは、電気的に結合する。その結果、当該場合、第１共振回路ＲＣ１と第３共振回路ＲＣ３とのそれぞれは、互いの共振に応じて共振する。これは、第３共振回路ＲＣ３によって構成された超伝導量子ビットが有する２つの量子状態（すなわち、|０〉と|１〉）を表す仮想的なスピンが、第１共振回路ＲＣ１によって構成された超伝導量子ビットが有する２つの量子状態（すなわち、|０〉と|１〉）を表す仮想的なスピンの状態に応じた力を受けること（すなわち、これら２つのスピン間相互作用が発生していること（オンの状態であること））を意味している。また、当該相互作用の強さは、第１ジョセフソン接合素子Ｊ１～第４ジョセフソン接合素子Ｊ４のそれぞれが有するジョセフソンエネルギーの大きくするほど大きくなる。このため、制御回路２では、当該ジョセフソンエネルギーを大きくすることにより、当該相互作用の強さを強くすることができる。 On the other hand, when the switch of the power supply PW is on, the first resonance circuit RC1 and the third resonance circuit RC3 are electrically coupled. As a result, in this case, each of the first resonance circuit RC1 and the third resonance circuit RC3 resonates according to the mutual resonance. This is because a virtual spin representing two quantum states (ie, | 0> and | 1>) of the superconducting qubit formed by the third resonance circuit RC3 is formed by the first resonance circuit RC1. Receiving a force corresponding to a virtual spin state representing two quantum states (ie, | 0> and | 1>) of a superconducting qubit (ie, the interaction between these two spins is generated) (That it is in an on state)). The strength of the interaction increases as the Josephson energy of each of the first Josephson junction element J1 to the fourth Josephson junction element J4 increases. For this reason, in the control circuit 2, the strength of the interaction can be increased by increasing the Josephson energy.
　このように制御回路２は、第１共振回路ＲＣ１と第２共振回路ＲＣ２とが結合した場合における結合の強さを強くしつつ、制御回路２が有する第１共振回路ＲＣ１及び第３共振回路ＲＣ３のそれぞれにより構成された超伝導量子ビット間の相互作用のオン／オフを切り替えることができる。その結果、制御回路２は、制御回路２を備えた量子計算機における量子計算において誤りが発生してしまうことを抑制することができる。 As described above, the control circuit 2 increases the coupling strength when the first resonance circuit RC1 and the second resonance circuit RC2 are coupled, and the first resonance circuit RC1 and the third resonance circuit RC3 that the control circuit 2 has. It is possible to switch on / off the interaction between the superconducting qubits configured by each of the above. As a result, the control circuit 2 can suppress an error from occurring in the quantum calculation in the quantum computer including the control circuit 2.
　図６は、複数の制御回路２を集積させた集積回路の一例を示す図である。例えば、図６に示した集積回路に含まれる部分回路ＰＣ３は、第３共振回路ＲＣ３（より具体的には、第５ジョセフソン接合素子Ｊ５）を２つの制御回路２において共有させた回路である。すなわち、制御回路２を集積化する方法の概念は、図３に示した印ＭＫ２を、第３共振回路ＲＣ３を示す図示しない印ＭＫ４に置き換えた概念と同様である。 FIG. 6 is a diagram illustrating an example of an integrated circuit in which a plurality of control circuits 2 are integrated. For example, the partial circuit PC3 included in the integrated circuit shown in FIG. 6 is a circuit in which the third control circuit RC3 (more specifically, the fifth Josephson junction element J5) is shared by the two control circuits 2. . That is, the concept of the method of integrating the control circuit 2 is the same as the concept in which the mark MK2 shown in FIG. 3 is replaced with a mark MK4 (not shown) showing the third resonance circuit RC3.
　このように複数の制御回路２同士を、第１共振回路ＲＣ１と第３共振回路ＲＣ３の少なくとも一方を共有させて接続させることにより、複数の制御回路２が集積化された集積回路を作成する作成者は、当該集積回路を作成することができる。すなわち、当該作成者は、変調回路ＭＣを介して複数の第１共振回路ＲＣ１と複数の第３共振回路ＲＣ３とを交互に接続し、第１共振回路ＲＣ１と第３共振回路ＲＣ３とを二次元的に集積回路化することができる。その結果、当該集積回路は、図４に示した集積回路と比べて第２共振回路ＲＣ２の分だけ小さくすること、もしくは図４に示した集積回路と比べて超伝導量子ビットを構成する量子ビット回路（この一例において、第１共振回路ＲＣ１及び第３共振回路ＲＣ３）の数を増やすことができる。また、図６に示した集積回路のように制御回路２を集積する場合、当該集積回路の作成者は、当該集積回路における配線の簡略化ができる。その結果、当該集積回路は、当該場合ではない場合と比較して、より容易に作成できるとともに、より安価に作成することができる。 In this way, a plurality of control circuits 2 are connected to each other by sharing at least one of the first resonance circuit RC1 and the third resonance circuit RC3, thereby creating an integrated circuit in which the plurality of control circuits 2 are integrated. A person can create the integrated circuit. That is, the creator alternately connects the plurality of first resonance circuits RC1 and the plurality of third resonance circuits RC3 via the modulation circuit MC, and connects the first resonance circuit RC1 and the third resonance circuit RC3 two-dimensionally. Thus, an integrated circuit can be obtained. As a result, the integrated circuit is made smaller by the second resonant circuit RC2 than the integrated circuit shown in FIG. 4, or the qubits constituting the superconducting qubit as compared with the integrated circuit shown in FIG. The number of circuits (in this example, the first resonance circuit RC1 and the third resonance circuit RC3) can be increased. When the control circuit 2 is integrated like the integrated circuit shown in FIG. 6, the creator of the integrated circuit can simplify the wiring in the integrated circuit. As a result, the integrated circuit can be created more easily and at a lower cost than in the case where the integrated circuit is not.
　また、図６に示したように複数の制御回路２を集積することにより、例えば、部分回路ＰＣ３が有する１つの電源ＰＷそれぞれのスイッチをオンにした場合、部分回路ＰＣ３が有する１つの変調回路ＭＣを介して、部分回路ＰＣ３が有する第１共振回路ＲＣ１及び第３共振回路ＲＣ３のそれぞれが構成する超伝導量子ビット間において相互作用が発生する。また、部分回路ＰＣ３が有する１つの電源ＰＷのスイッチをオフにした場合、部分回路ＰＣ３が有する第１共振回路ＲＣ１及び第３共振回路ＲＣ３のそれぞれが構成する超伝導量子ビット間における相互作用が消失する。このように、図６に示したように複数の制御回路２を集積することにより、当該複数の制御回路２を備える量子計算機は、ユーザーが所望する任意の隣り合う２つの超伝導量子ビット間の相互作用のオン／オフを切り替えることができる。その結果、当該量子計算機は、量子計算において誤りが発生してしまうことを抑制することができる。 Further, by integrating a plurality of control circuits 2 as shown in FIG. 6, for example, when each switch of one power supply PW included in the partial circuit PC3 is turned on, one modulation circuit MC included in the partial circuit PC3. Through the above, an interaction occurs between the superconducting qubits formed by each of the first resonance circuit RC1 and the third resonance circuit RC3 included in the partial circuit PC3. Further, when the switch of one power supply PW included in the partial circuit PC3 is turned off, the interaction between the superconducting qubits formed by each of the first resonance circuit RC1 and the third resonance circuit RC3 included in the partial circuit PC3 is lost. To do. In this way, by integrating a plurality of control circuits 2 as shown in FIG. 6, a quantum computer including the plurality of control circuits 2 can be used between any two adjacent superconducting qubits desired by the user. The interaction can be switched on / off. As a result, the quantum computer can suppress an error from occurring in the quantum calculation.
　また、図６に示したように複数の制御回路２を集積することにより、図６に示した集積回路を有する量子計算機は、量子計算中において、当該集積回路が有する複数の第１共振回路ＲＣ１のそれぞれ及び複数の第３共振回路ＲＣ３のそれぞれが構成する超伝導量子ビットのいずれか１つの超伝導量子ビットにおいて誤りが生じた場合であっても、当該超伝導量子ビットを構成する第１共振回路ＲＣ１に接続された電源ＰＷのスイッチがオフである限り、当該誤りが他の超伝導量子ビットを構成する第１共振回路ＲＣ１又は第３共振回路ＲＣ３に伝播してしまうことを抑制することができる。 In addition, by integrating a plurality of control circuits 2 as shown in FIG. 6, the quantum computer having the integrated circuit shown in FIG. 6 can perform a plurality of first resonance circuits RC1 included in the integrated circuit during the quantum calculation. Even if an error occurs in any one of the superconducting qubits constituted by each of the third resonance circuits RC3 and the first resonance circuit RC3, the first resonance constituting the superconducting qubits As long as the switch of the power supply PW connected to the circuit RC1 is off, it is possible to prevent the error from propagating to the first resonance circuit RC1 or the third resonance circuit RC3 constituting another superconducting qubit. it can.
　なお、複数の制御回路２は、図６に示したように二次元的に集積される構成に代えて、三次元的に集積される構成であってもよい。この場合、ある二次元平面上に集積された複数の制御回路２のそれぞれは、例えば、当該二次元平面と直交する方向に重なる他の二次元平面上に集積された複数の制御回路２のそれぞれとビアを用いて電気的に接続される。 The plurality of control circuits 2 may be configured to be integrated three-dimensionally instead of the configuration integrated two-dimensionally as shown in FIG. In this case, each of the plurality of control circuits 2 integrated on a certain two-dimensional plane is, for example, each of the plurality of control circuits 2 integrated on another two-dimensional plane overlapping in a direction orthogonal to the two-dimensional plane. And are electrically connected using vias.
　＜実施形態の変形例２＞
　以下、図７を参照し、実施形態の変形例２について説明する。なお、実施形態の変形例２では、実施形態と同様な構成部に対して同じ符号を付して説明を省略する。 <Modification 2 of Embodiment>
Hereinafter, a second modification of the embodiment will be described with reference to FIG. In the second modification of the embodiment, the same reference numerals are given to the same components as those in the embodiment, and the description thereof is omitted.
　実施形態において説明した制御回路１は、第１共振回路ＲＣ１に代えて、第１共振回路ＲＣ１によって構成された超伝導量子ビットと異なる超伝導量子ビットを構成する共振回路を備える構成であってもよい。以下では、第１共振回路ＲＣ１に代えて当該共振回路を備える制御回路１を、制御回路３と称して説明する。以下では、一例として、当該共振回路が図７に示した第４共振回路ＲＣ４である場合について説明する。図７は、実施形態の変形例２に係る制御回路３の構成の一例を示す図である。 The control circuit 1 described in the embodiment may include a resonance circuit that configures a superconducting qubit different from the superconducting qubit configured by the first resonance circuit RC1 instead of the first resonance circuit RC1. Good. Hereinafter, the control circuit 1 including the resonance circuit instead of the first resonance circuit RC1 will be described as a control circuit 3. Below, the case where the said resonance circuit is 4th resonance circuit RC4 shown in FIG. 7 as an example is demonstrated. FIG. 7 is a diagram illustrating an example of a configuration of the control circuit 3 according to the second modification of the embodiment.
　制御回路３は、変調回路ＭＣと、第２共振回路ＲＣ２と、第４共振回路ＲＣ４と、電源ＰＷを備える。なお、制御回路３は、これら３つの回路及び電源ＰＷに加えて、他の回路を備える構成であってもよい。ただし、この場合、当該他の回路は、以下において説明する制御回路３が有する特徴を壊さないように制御回路３に備えられなければならない。換言すると、以下において説明する制御回路３が有する特徴を壊さなければ、制御回路３は、如何なる変更を受けてもよい。 The control circuit 3 includes a modulation circuit MC, a second resonance circuit RC2, a fourth resonance circuit RC4, and a power supply PW. The control circuit 3 may be configured to include other circuits in addition to these three circuits and the power supply PW. However, in this case, the other circuit must be provided in the control circuit 3 so as not to break the characteristics of the control circuit 3 described below. In other words, the control circuit 3 may be subjected to any changes as long as the characteristics of the control circuit 3 described below are not destroyed.
　第４共振回路ＲＣ４は、第１共振回路ＲＣ１において第０ジョセフソン接合素子Ｊ０を回路ＣＣに置き換えた共振回路である。すなわち、第４共振回路ＲＣ４において、回路ＣＣは、第１キャパシターＣ１と第２キャパシターＣ２との間に位置する。
　回路ＣＣは、第６ジョセフソン接合素子Ｊ６と、第７ジョセフソン接合素子Ｊ７と、第８ジョセフソン接合素子Ｊ８を備える環状回路である。ここで、第６ジョセフソン接合素子Ｊ６、第７ジョセフソン接合素子Ｊ７、第８ジョセフソン接合素子Ｊ８のそれぞれがインダクターとして振る舞うため、回路ＣＣを備える第４共振回路ＲＣ４は、共振する。 The fourth resonance circuit RC4 is a resonance circuit obtained by replacing the 0th Josephson junction element J0 with the circuit CC in the first resonance circuit RC1. That is, in the fourth resonance circuit RC4, the circuit CC is located between the first capacitor C1 and the second capacitor C2.
The circuit CC is a ring circuit including a sixth Josephson junction element J6, a seventh Josephson junction element J7, and an eighth Josephson junction element J8. Here, since each of the sixth Josephson junction element J6, the seventh Josephson junction element J7, and the eighth Josephson junction element J8 behaves as an inductor, the fourth resonance circuit RC4 including the circuit CC resonates.
　第６ジョセフソン接合素子Ｊ６及び第７ジョセフソン接合素子Ｊ７のそれぞれは、０接合のジョセフソン接合素子である。なお、第６ジョセフソン接合素子Ｊ６及び第７ジョセフソン接合素子Ｊ７のうちいずれか一方又は両方は、０接合のジョセフソン接合素子に代えて、π接合のジョセフソン接合素子であってもよい。 Each of the sixth Josephson junction element J6 and the seventh Josephson junction element J7 is a zero junction Josephson junction element. Note that one or both of the sixth Josephson junction element J6 and the seventh Josephson junction element J7 may be a π junction Josephson junction element instead of the 0 junction Josephson junction element.
　第８ジョセフソン接合素子Ｊ８は、π接合のジョセフソン接合素子である。なお、第８ジョセフソン接合素子Ｊ８は、π接合のジョセフソン接合素子に代えて、０接合のジョセフソン接合素子であってもよい。第８ジョセフソン接合素子Ｊ８は、回路ＣＣにおいて、第６ジョセフソン接合素子Ｊ６と第７ジョセフソン接合素子Ｊ７との間に位置する。 The eighth Josephson junction element J8 is a π junction Josephson junction element. The eighth Josephson junction element J8 may be a 0-junction Josephson junction element instead of the π-junction Josephson junction element. The eighth Josephson junction element J8 is located between the sixth Josephson junction element J6 and the seventh Josephson junction element J7 in the circuit CC.
　ここで、制御回路３において、第１接点Ｐ１と第１キャパシターＣ１との間と、第６ジョセフソン接合素子Ｊ６と第８ジョセフソン接合素子Ｊ８との間とが接続されている。また、制御回路３において、第３接点Ｐ３と第２キャパシターＣ２との間と、第７ジョセフソン接合素子Ｊ７と第８ジョセフソン接合素子Ｊ８との間とが接続されている。 Here, in the control circuit 3, the first contact P1 and the first capacitor C1 and the sixth Josephson junction element J6 and the eighth Josephson junction element J8 are connected. Further, in the control circuit 3, the third contact P3 and the second capacitor C2 and the seventh Josephson junction element J7 and the eighth Josephson junction element J8 are connected.
　このように、制御回路３が第２共振回路ＲＣ２と第４共振回路ＲＣ４を備える場合、回路量子電磁力学に基づく制御回路３のハミルトニアンの構造は、上記の式（１）に示したハミルトニアンとほぼ同じ構造になる。このため、電源ＰＷのスイッチがオフの場合、位相φＺが常に０であり、制御回路３において第２共振回路ＲＣ２と第４共振回路ＲＣ４とは、電気的に結合することができない。その結果、当該場合、第２共振回路ＲＣ２と第４共振回路ＲＣ４のそれぞれは、互いに独立に（互いに無関係に）共振する。これは、第４共振回路ＲＣ４によって構成された超伝導量子ビットが有する２つの量子状態（すなわち、|０〉と|１〉）を表す仮想的なスピンと、第２共振回路ＲＣ２の共振を表す仮想的な調和振動子との間の相互作用が存在しない（消える、消失する）ことを意味している。また、これは、第１ジョセフソン接合素子Ｊ１～第４ジョセフソン接合素子Ｊ４のそれぞれが有するジョセフソンエネルギーの大きさと無関係に起こる現象である。このため、当該相互作用の強さを強くしたとしても、電源ＰＷのスイッチをオフにすることにより、制御回路３では、当該相互作用をオフの状態にすることができる。 As described above, when the control circuit 3 includes the second resonance circuit RC2 and the fourth resonance circuit RC4, the Hamiltonian structure of the control circuit 3 based on the circuit quantum electrodynamics is almost the same as the Hamiltonian shown in the above equation (1). It becomes the same structure. Therefore, when the switch of the power source PW is turned off, the phase phi Z is always 0, the control circuit 3 and the second resonant circuit RC2 and the fourth resonant circuit RC4, can not be electrically coupled. As a result, in this case, the second resonance circuit RC2 and the fourth resonance circuit RC4 resonate independently of each other (independently of each other). This represents a virtual spin representing two quantum states (that is, | 0> and | 1>) included in the superconducting qubit formed by the fourth resonance circuit RC4 and resonance of the second resonance circuit RC2. This means that there is no interaction (disappears or disappears) with the virtual harmonic oscillator. This is a phenomenon that occurs regardless of the magnitude of the Josephson energy of each of the first Josephson junction element J1 to the fourth Josephson junction element J4. For this reason, even if the strength of the interaction is increased, the interaction can be turned off in the control circuit 3 by turning off the switch of the power source PW.
　一方、電源ＰＷのスイッチがオンの場合、第２共振回路ＲＣ２と第４共振回路ＲＣ４とは、電気的に結合する。その結果、当該場合、第２共振回路ＲＣ２と第４共振回路ＲＣ４とのそれぞれは、互いの共振に応じて共振する。これは、第２共振回路ＲＣ２の共振を表す仮想的な調和振動子が、第４共振回路ＲＣ４によって構成された超伝導量子ビットが有する２つの量子状態（すなわち、|０〉と|１〉）を表す仮想的なスピンの状態に応じた力を受けること（すなわち、当該調和振動子と当該スピンとの間の相互作用が存在すること）を意味している。また、当該相互作用の強さは、第１ジョセフソン接合素子Ｊ１～第４ジョセフソン接合素子Ｊ４のそれぞれが有するジョセフソンエネルギーの大きくするほど大きくなる。このため、制御回路３では、当該ジョセフソンエネルギーを大きくすることにより、当該相互作用の強さを強くすることができる。 On the other hand, when the switch of the power supply PW is on, the second resonance circuit RC2 and the fourth resonance circuit RC4 are electrically coupled. As a result, in this case, each of the second resonance circuit RC2 and the fourth resonance circuit RC4 resonates according to the mutual resonance. This is because the virtual harmonic oscillator representing the resonance of the second resonance circuit RC2 has two quantum states (ie, | 0> and | 1>) that the superconducting qubit formed by the fourth resonance circuit RC4 has. It means that a force corresponding to a virtual spin state representing (that is, an interaction between the harmonic oscillator and the spin exists). The strength of the interaction increases as the Josephson energy of each of the first Josephson junction element J1 to the fourth Josephson junction element J4 increases. For this reason, in the control circuit 3, the strength of the interaction can be increased by increasing the Josephson energy.
　このように制御回路３は、第２共振回路ＲＣ２と第４共振回路ＲＣ４とが結合した場合における結合の強さを強くしつつ、制御回路３が有する第２共振回路ＲＣ２と第４共振回路ＲＣ４との間の相互作用のオン／オフを切り替えることができる。その結果、制御回路３は、実施形態と同様の効果を得ることができる。 In this way, the control circuit 3 increases the strength of the coupling when the second resonance circuit RC2 and the fourth resonance circuit RC4 are coupled, and the second resonance circuit RC2 and the fourth resonance circuit RC4 that the control circuit 3 has. Can be switched on / off. As a result, the control circuit 3 can obtain the same effect as the embodiment.
　なお、上記において説明した制御回路１～制御回路３のそれぞれは、超伝導量子ビットを構成する共振回路（例えば、制御回路１の場合、第１共振回路ＲＣ１）に代えて、他の量子ビットを構成する回路が接続される構成であってもよい。当該他の量子ビットは、既知の量子ビットであってもよく、これから開発される量子ビットであってもよい。この場合、当該回路は、当該量子ビットが有する２つの量子状態に応じて電流が振動するように構成される。 Note that each of the control circuit 1 to control circuit 3 described above replaces the resonance circuit (for example, the first resonance circuit RC1 in the case of the control circuit 1) constituting the superconducting qubit with another qubit. The structure to which the circuit to comprise may be connected may be sufficient. The other qubits may be known qubits or qubits to be developed in the future. In this case, the circuit is configured such that the current oscillates according to two quantum states of the qubit.
　以上のように、変調回路（上記において説明した例では、変調回路ＭＣ）は、第１接点（上記において説明した例では、第１接点Ｐ１）と、第２接点（上記において説明した例では、第２接点Ｐ２）と、第３接点（上記において説明した例では、第３接点Ｐ３）と、第４接点（上記において説明した例では、第４接点Ｐ４）とを有し、第１接点と第３接点とに第１共振回路（上記において説明した例では、第１共振回路ＲＣ１）が接続され、第２接点と第４接点とに第２共振回路（上記において説明した例では、第２共振回路ＲＣ２）が接続された環状回路であって、第１接点における電位の時間積分によって表される位相である第１位相（上記において説明した例では、第１位相φ１）と、第２接点（上記において説明した例では、第２位相φ２）における電位の時間積分によって表される位相である第２位相と、第３接点における電位の時間積分によって表される位相である第３位相（上記において説明した例では、第３位相φ３）と、第４接点における電位の時間積分によって表される位相である第４位相（上記において説明した例では、第４位相φ４）とに基づいて、第１共振回路と第２共振回路との結合状態を変化させる。また、変調回路は、第１位相と、前記第２位相と、前記第３位相と、前記第４位相とに基づいて、結合状態を、第１共振回路と第２共振回路とが結合していない状態と、第１共振回路と第２共振回路とが結合している状態とのいずれかに変化させる。これにより、変調回路は、第１共振回路と第２共振回路の電気的な結合を切ることができる。 As described above, the modulation circuit (in the example described above, the modulation circuit MC) includes the first contact (in the example described above, the first contact P1) and the second contact (in the example described above, A second contact P2), a third contact (in the example described above, the third contact P3), and a fourth contact (in the example described above, the fourth contact P4), A first resonance circuit (in the example described above, the first resonance circuit RC1) is connected to the third contact, and a second resonance circuit (in the example described above, the second resonance circuit RC1) is connected to the second contact and the fourth contact. A ring circuit to which a resonance circuit RC2) is connected, and a first phase (in the example described above, the first phase φ 1 ) that is a phase represented by time integration of the potential at the first contact, and a second phase Contact (in the example described above, second place A second phase that is a phase represented by time integration of the potential in the phase φ 2 ) and a third phase that is a phase represented by time integration of the potential at the third contact (in the example described above, the third phase). and phi 3), in the example described in the fourth phase (above the phase represented by the time integral of the potential at the fourth contact point, based on the fourth phase phi 4) and the first resonant circuit and the second resonance The coupling state with the circuit is changed. The modulation circuit has a coupling state based on the first phase, the second phase, the third phase, and the fourth phase, and the first resonance circuit and the second resonance circuit are coupled. The state is changed to either a state in which the first resonance circuit and the second resonance circuit are coupled to each other. Thereby, the modulation circuit can disconnect the electrical coupling between the first resonance circuit and the second resonance circuit.
　また、変調回路は、第１共振回路と第２共振回路とのそれぞれに交流電圧を供給する電源（上記において説明した例では、電源ＰＷ）により第１共振回路と第２共振回路とのそれぞれへの交流電圧の供給が開始された場合、結合状態を第１共振回路と第２共振回路とが結合している状態に変化させ、電源により第１共振回路と第２共振回路とのそれぞれへの交流電圧の供給が停止された場合、当該結合状態を第１共振回路と第２共振回路とが結合していない状態に変化させる。これにより、変調回路は、第１共振回路と第２共振回路とのそれぞれへの電源による交流電圧の供給状態に応じて、第１共振回路と第２共振回路の結合状態を切り替えることができる。 Further, the modulation circuit is supplied to each of the first resonance circuit and the second resonance circuit by a power source (in the example described above, the power source PW) that supplies an AC voltage to each of the first resonance circuit and the second resonance circuit. When the supply of the AC voltage is started, the coupling state is changed to a state where the first resonance circuit and the second resonance circuit are coupled, and the power supply to each of the first resonance circuit and the second resonance circuit is performed. When the supply of the AC voltage is stopped, the coupling state is changed to a state where the first resonance circuit and the second resonance circuit are not coupled. Thereby, the modulation circuit can switch the coupling state of the first resonance circuit and the second resonance circuit according to the supply state of the AC voltage by the power source to each of the first resonance circuit and the second resonance circuit.
　また、変調回路は、０接合の第１ジョセフソン接合素子（上記において説明した例では、第１ジョセフソン接合素子Ｊ１）と、０接合の第２ジョセフソン接合素子（上記において説明した例では、第２ジョセフソン接合素子Ｊ２）と、π接合の第３ジョセフソン接合素子（上記において説明した例では、第３ジョセフソン接合素子Ｊ３）と、π接合の第４ジョセフソン接合素子（上記において説明した例では、第４ジョセフソン接合素子Ｊ４）とを備え、第１ジョセフソン接合素子が第１接点と第２接点との間に位置し、第２ジョセフソン接合素子が第２接点と第３接点との間に位置し、第３ジョセフソン接合素子が第３接点と第４接点との間に位置し、第４ジョセフソン接合素子が第４接点と第１接点との間に位置する。これにより、変調回路は、第１ジョセフソン接合素子～第４ジョセフソン接合素子に基づいて、第１共振回路と第２共振回路の結合状態を切り替えることができる。 In addition, the modulation circuit includes a 0-junction first Josephson junction element (in the example described above, the first Josephson junction element J1) and a 0-junction second Josephson junction element (in the example described above, The second Josephson junction element J2), the third Josephson junction element of π junction (in the example described above, the third Josephson junction element J3), and the fourth Josephson junction element of π junction (described above). In this example, a fourth Josephson junction element J4) is provided, the first Josephson junction element is located between the first contact and the second contact, and the second Josephson junction element is the second contact and the third contact. The third Josephson junction element is located between the third contact and the fourth contact, and the fourth Josephson junction element is located between the fourth contact and the first contact. Thereby, the modulation circuit can switch the coupling state of the first resonance circuit and the second resonance circuit based on the first to fourth Josephson junction elements.
　また、変調回路は、第１共振回路と第２共振回路のうちの少なくとも一方が、ジョセフソン接合素子（上記において説明した例では、第０ジョセフソン接合素子Ｊ０、第５ジョセフソン接合素子Ｊ５、第６ジョセフソン接合素子Ｊ６～第８ジョセフソン接合素子Ｊ８）を含む量子ビット回路である。これにより、変調回路は、第１共振回路と第２共振回路の少なくとも一方がジョセフソン接合素子を含む量子ビット回路である場合において、第１共振回路と第２共振回路の結合状態を切り替えることができる。 In the modulation circuit, at least one of the first resonance circuit and the second resonance circuit is a Josephson junction element (in the example described above, the 0th Josephson junction element J0, the fifth Josephson junction element J5, This is a qubit circuit including sixth Josephson junction element J6 to eighth Josephson junction element J8). Accordingly, the modulation circuit can switch the coupling state between the first resonance circuit and the second resonance circuit when at least one of the first resonance circuit and the second resonance circuit is a qubit circuit including a Josephson junction element. it can.
　また、変調回路は、第１共振回路と前記第２共振回路のうちのいずれか一方が、ジョセフソン接合素子を含む量子ビット回路である。これにより、変調回路は、第１共振回路と第２共振回路のいずれか一方がジョセフソン接合素子を含む量子ビット回路である場合において、第１共振回路と第２共振回路の結合状態を切り替えることができる。 Further, the modulation circuit is a qubit circuit in which either one of the first resonance circuit and the second resonance circuit includes a Josephson junction element. Thereby, the modulation circuit switches the coupling state of the first resonance circuit and the second resonance circuit when either the first resonance circuit or the second resonance circuit is a qubit circuit including a Josephson junction element. Can do.
　また、変調回路は、第１共振回路と第２共振回路のうち量子ビット回路と異なる共振回路が、量子ビット回路の量子状態を読み出す読出回路を備える。これにより、変調回路は、第１共振回路と第２共振回路のうち量子ビット回路と異なる共振回路を用いて、第１共振回路と第２共振回路のうち量子ビット回路である共振回路の量子状態を読み出すことができる。 Further, the modulation circuit includes a readout circuit in which a resonance circuit different from the qubit circuit among the first resonance circuit and the second resonance circuit reads the quantum state of the qubit circuit. Accordingly, the modulation circuit uses a resonance circuit different from the qubit circuit among the first resonance circuit and the second resonance circuit, and the quantum state of the resonance circuit that is the qubit circuit among the first resonance circuit and the second resonance circuit. Can be read out.
　また、制御回路（上記において説明した例では、制御回路１～制御回路３）は、上記に記載の変調回路と、第１共振回路と、第２共振回路と、第１共振回路と第２共振回路とのそれぞれに交流電圧を供給する電源と、を備える。また、制御回路では、電源が供給する交流電圧の周波数は、前記第１共振回路と前記第２共振回路とのうち少なくとも一方の共振周波数である。また、制御回路では、電源により第１共振回路と第２共振回路とのそれぞれへの交流電圧の供給が開始された場合、第１共振回路の量子状態の変化に応じて、第２共振回路の量子状態が変化する。また、制御回路は、第１共振回路の量子状態の変化に応じて第２共振回路の量子状態が変化する。また、制御回路では、第２共振回路の量子状態の変化は、第１位相と、第２位相と、第３位相と、第４位相と、第１共振回路の量子状態の変化とに応じた変化である。これにより、第１共振回路と第２共振回路の電気的な結合を切ることができる。 In addition, the control circuit (in the example described above, the control circuit 1 to the control circuit 3) includes the modulation circuit, the first resonance circuit, the second resonance circuit, the first resonance circuit, and the second resonance circuit described above. And a power supply for supplying an AC voltage to each of the circuits. In the control circuit, the frequency of the AC voltage supplied by the power supply is at least one of the resonance frequency of the first resonance circuit and the second resonance circuit. Further, in the control circuit, when the supply of the AC voltage to each of the first resonance circuit and the second resonance circuit is started by the power source, the second resonance circuit of the second resonance circuit is changed according to the change of the quantum state of the first resonance circuit. The quantum state changes. In the control circuit, the quantum state of the second resonance circuit changes according to the change of the quantum state of the first resonance circuit. In the control circuit, the change in the quantum state of the second resonance circuit is in accordance with the first phase, the second phase, the third phase, the fourth phase, and the change in the quantum state of the first resonance circuit. It is a change. Thereby, the electrical coupling between the first resonance circuit and the second resonance circuit can be cut.
　また、制御回路は、電源により第１共振回路と第２共振回路とのそれぞれへの交流電圧の供給が停止された場合、第１共振回路の量子状態と、第２共振回路の量子状態とが独立に変化する。これにより、制御回路は、電源により第１共振回路と第２共振回路とのそれぞれへの交流電圧の供給を停止することによって、第１共振回路と第２共振回路との結合状態を、第１共振回路と第２共振回路が結合していない状態に切り替えることができる。 In addition, when the supply of AC voltage to each of the first resonance circuit and the second resonance circuit is stopped by the power supply, the control circuit has a quantum state of the first resonance circuit and a quantum state of the second resonance circuit. It changes independently. Thereby, the control circuit stops the supply of the AC voltage to each of the first resonance circuit and the second resonance circuit by the power source, thereby changing the coupling state between the first resonance circuit and the second resonance circuit to the first resonance circuit. It is possible to switch to a state where the resonance circuit and the second resonance circuit are not coupled.
　以上、この発明の実施形態を、図面を参照して詳述してきたが、具体的な構成はこの実施形態に限られるものではなく、この発明の要旨を逸脱しない限り、変更、置換、削除等されてもよい。 The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and changes, substitutions, deletions, and the like are possible without departing from the gist of the present invention. May be.
１、２、３　　制御回路
Ｃ１　　第１キャパシター
Ｃ２　　第２キャパシター
Ｃ３　　第３キャパシター
Ｃ４　第４キャパシター
ＣＣ　　回路
Ｊ０　　第０ジョセフソン接合素子
Ｊ１　　第１ジョセフソン接合素子
Ｊ２　　第２ジョセフソン接合素子
Ｊ３　　第３ジョセフソン接合素子
Ｊ４　　第４ジョセフソン接合素子
Ｊ５　　第５ジョセフソン接合素子
Ｊ６　　第６ジョセフソン接合素子
Ｊ７　　第７ジョセフソン接合素子
Ｊ８　　第８ジョセフソン接合素子
Ｌ１　　インダクター
ＭＣ　　変調回路
ＭＫ１～ＭＫ４　　印
Ｐ１　　第１接点
Ｐ２　　第２接点
Ｐ３　　第３接点
Ｐ４　　第４接点
ＰＣ１～ＰＣ３　　部分回路
ＰＷ　　電源
ＲＣ１　　第１共振回路
ＲＣ２　　第２共振回路
ＲＣ３　　第３共振回路
ＲＣ４　　第４共振回路
Ｔ１　　第１端子
Ｔ２　　第２端子 1, 2, 3 Control circuit C1 1st capacitor C2 2nd capacitor C3 3rd capacitor C4 4th capacitor CC circuit J0 0th Josephson junction element J1 1st Josephson junction element J2 2nd Josephson junction element J3 3rd Joseph Son Junction Element J4 4th Josephson Junction Element J5 5th Josephson Junction Element J6 6th Josephson Junction Element J7 7th Josephson Junction Element J8 8th Josephson Junction Element L1 Inductor MC Modulation Circuits MK1-MK4 Mark P1 1st Contact P2 Second contact P3 Third contact P4 Fourth contact PC1 to PC3 Partial circuit PW Power supply RC1 First resonance circuit RC2 Second resonance circuit RC3 Third resonance circuit RC4 Fourth resonance circuit T1 First terminal T2 Second terminal

Claims (18)

  1. 　第１接点と、第２接点と、第３接点と、第４接点とを有し、前記第１接点と前記第３接点とに第１共振回路が接続され、前記第２接点と前記第４接点とに第２共振回路が接続された環状回路であって、
    　前記第１接点における電位の時間積分によって表される位相である第１位相と、前記第２接点における電位の時間積分によって表される位相である第２位相と、前記第３接点における電位の時間積分によって表される位相である第３位相と、前記第４接点における電位の時間積分によって表される位相である第４位相とに基づいて、前記第１共振回路と前記第２共振回路との結合状態を変化させる、
    　変調回路。     A first contact, a second contact, a third contact, and a fourth contact; a first resonance circuit connected to the first contact and the third contact; and the second contact and the fourth contact. A ring circuit in which a second resonance circuit is connected to a contact;
    A first phase that is a phase represented by time integration of a potential at the first contact; a second phase that is a phase represented by time integration of a potential at the second contact; and a time of a potential at the third contact. Based on the third phase, which is a phase represented by integration, and the fourth phase, which is a phase represented by time integration of the potential at the fourth contact, the first resonance circuit and the second resonance circuit Change the binding state,
    Modulation circuit.
  2. 　前記第１位相と、前記第２位相と、前記第３位相と、前記第４位相とに基づいて、前記結合状態を、前記第１共振回路と前記第２共振回路とが結合していない状態と、前記第１共振回路と前記第２共振回路とが結合している状態とのいずれかに変化させる、
    　請求項１に記載の変調回路。     Based on the first phase, the second phase, the third phase, and the fourth phase, the coupling state is a state in which the first resonance circuit and the second resonance circuit are not coupled. And the first resonance circuit and the second resonance circuit are coupled to each other.
    The modulation circuit according to claim 1.
  3. 　前記第１共振回路と前記第２共振回路とのそれぞれに交流電圧を供給する電源により前記第１共振回路と前記第２共振回路とのそれぞれへの前記交流電圧の供給が開始された場合、前記結合状態を前記第１共振回路と前記第２共振回路とが結合している状態に変化させ、前記電源により前記第１共振回路と前記第２共振回路とのそれぞれへの前記交流電圧の供給が停止された場合、前記結合状態を前記第１共振回路と前記第２共振回路とが結合していない状態に変化させる、
    　請求項１又は２に記載の変調回路。     When supply of the AC voltage to each of the first resonance circuit and the second resonance circuit is started by a power source that supplies an AC voltage to each of the first resonance circuit and the second resonance circuit, The coupling state is changed to a state in which the first resonance circuit and the second resonance circuit are coupled, and the supply of the AC voltage to each of the first resonance circuit and the second resonance circuit is performed by the power source. When stopped, the coupling state is changed to a state where the first resonance circuit and the second resonance circuit are not coupled;
    The modulation circuit according to claim 1.
  4. 　前記第１接点と前記第２接点との間に位置する０接合の第１ジョセフソン接合素子を備えた、
    　請求項１から３のうちいずれか一項に記載の変調回路。     A zero-junction first Josephson junction element located between the first contact and the second contact;
    The modulation circuit according to any one of claims 1 to 3.
  5. 　前記第２接点と前記第３接点との間に位置する０接合の第２ジョセフソン接合素子を備えた、
    　請求項１から４のうちいずれか一項に記載の変調回路。     A zero-junction second Josephson junction element located between the second contact and the third contact;
    The modulation circuit according to any one of claims 1 to 4.
  6. 　前記第３接点と前記第４接点との間に位置するπ接合の第３ジョセフソン接合素子を備えた、
    　請求項１から５のうちいずれか一項に記載の変調回路。     A third Josephson junction element having a π junction located between the third contact and the fourth contact;
    The modulation circuit according to any one of claims 1 to 5.
  7. 　前記第４接点と前記第１接点との間に位置するπ接合の第４ジョセフソン接合素子を備えた、
    　請求項１から６のうちいずれか一項に記載の変調回路。     A fourth Josephson junction element having a π junction located between the fourth contact and the first contact;
    The modulation circuit according to claim 1.
  8. 　前記第１共振回路と前記第２共振回路のうちの少なくとも一方が、ジョセフソン接合素子を含む量子ビット回路である、
    　請求項１から７のうちいずれか一項に記載の変調回路。     At least one of the first resonant circuit and the second resonant circuit is a qubit circuit including a Josephson junction element;
    The modulation circuit according to claim 1.
  9. 　前記第１共振回路と前記第２共振回路のうちのいずれか一方が、ジョセフソン接合素子を含む量子ビット回路である、
    　請求項８に記載の変調回路。     Either one of the first resonance circuit and the second resonance circuit is a qubit circuit including a Josephson junction element.
    The modulation circuit according to claim 8.
  10. 　前記第１共振回路と前記第２共振回路のうち前記量子ビット回路と異なる共振回路が、前記量子ビット回路の量子状態を読み出す読出回路を備える、
    　請求項９に記載の変調回路。     A resonance circuit different from the qubit circuit among the first resonance circuit and the second resonance circuit includes a readout circuit that reads a quantum state of the qubit circuit.
    The modulation circuit according to claim 9.
  11. 　請求項１から１０のうちいずれか一項に記載の変調回路と、
    　前記第１共振回路と、
    　前記第２共振回路と、
    　前記第１共振回路と前記第２共振回路とのそれぞれに交流電圧を供給する電源と、
    　を備える制御回路。     A modulation circuit according to any one of claims 1 to 10,
    The first resonant circuit;
    The second resonant circuit;
    A power supply for supplying an AC voltage to each of the first resonant circuit and the second resonant circuit;
    A control circuit comprising:
  12. 　前記電源が供給する交流電圧の周波数は、前記第１共振回路と前記第２共振回路とのうち少なくとも一方の共振周波数である、
    　請求項１１に記載の制御回路。     The frequency of the AC voltage supplied by the power supply is at least one of the resonance frequencies of the first resonance circuit and the second resonance circuit.
    The control circuit according to claim 11.
  13. 　前記電源により前記第１共振回路と前記第２共振回路とのそれぞれへの前記交流電圧の供給が開始された場合、前記第１共振回路の量子状態の変化に応じて前記第２共振回路の量子状態が変化する、
    　請求項１１又は１２に記載の制御回路。     When the supply of the AC voltage to each of the first resonance circuit and the second resonance circuit is started by the power source, the quantum of the second resonance circuit is changed according to the change of the quantum state of the first resonance circuit. The state changes,
    The control circuit according to claim 11 or 12.
  14. 　前記第２共振回路の量子状態の変化は、前記第１位相と、前記第２位相と、前記第３位相と、前記第４位相と、前記第１共振回路の量子状態の変化とに応じた変化である、
    　請求項１３に記載の制御回路。     The change in the quantum state of the second resonance circuit is in accordance with the first phase, the second phase, the third phase, the fourth phase, and the change in the quantum state of the first resonance circuit. Is a change,
    The control circuit according to claim 13.
  15. 　前記電源により前記第１共振回路と前記第２共振回路とのそれぞれへの前記交流電圧の供給が停止された場合、前記第１共振回路の量子状態と、前記第２共振回路の量子状態とが独立に変化する、
    　請求項１１から１４のうちいずれか一項に記載の制御回路。     When the supply of the AC voltage to each of the first resonance circuit and the second resonance circuit is stopped by the power source, the quantum state of the first resonance circuit and the quantum state of the second resonance circuit are Change independently,
    The control circuit according to claim 11.
  16. 　請求項１から１０のうちいずれか一項に記載の変調回路を備える、
    　情報処理装置。     Comprising the modulation circuit according to any one of claims 1 to 10,
    Information processing device.
  17. 　請求項１１から１５のうちいずれか一項に記載の制御回路を備える、
    　情報処理装置。     A control circuit according to any one of claims 11 to 15 is provided.
    Information processing device.
  18. 　請求項１から１０のうちいずれか一項に記載の変調回路を介して複数の前記第１共振回路と複数の前記第２共振回路とを交互に接続し、前記第１共振回路と前記第２共振回路とを二次元的又は三次元的に集積する、
    　集積方法。     A plurality of the first resonance circuits and a plurality of the second resonance circuits are alternately connected via the modulation circuit according to any one of claims 1 to 10, and the first resonance circuit and the second resonance circuit are connected. Integrating the resonant circuit in two or three dimensions,
    Integration method.
PCT/JP2018/008105 2017-03-03 2018-03-02 Modulation circuit, control circuit, information processing device, and integration method WO2018159832A1 (en)

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