Electronic circuits and computing devices
The described electronic circuit design, featuring a capacitive and inductive coupling of qubits and resonators, addresses the challenge of high-density integration and noise interference, enhancing performance in computing devices by reducing power needs and improving gate operation accuracy.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- KK TOSHIBA
- Filing Date
- 2023-04-06
- Publication Date
- 2026-07-03
AI Technical Summary
Existing electronic circuits and computing devices face challenges in achieving high-density integration and efficient power usage while minimizing low-frequency noise interference.
The implementation of an electronic circuit with a first coupler capacitively coupled to qubits, a first resonator inductively coupled to a loop, and a conductive member capacitively coupled to the resonator, allowing for excitation signal input to the resonator, which reduces power requirements and suppresses low-frequency noise.
This configuration enables high-density electronic circuits with reduced power consumption and improved noise resistance, facilitating efficient two-qubit gate operations with high accuracy.
Smart Images
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Abstract
Description
Technical Field
[0001] Embodiments of the present invention relate to electronic circuits and computing devices.
Background Art
[0002] For example, an electronic circuit including a plurality of non-linear elements is used in a computing device. In the electronic circuit and the computing device, an improvement in performance is desired.
Prior Art Documents
Non-Patent Documents
[0003]
Non-Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] Embodiments of the present invention provide an electronic circuit and a computing device capable of improving performance.
Means for Solving the Problems
[0005] According to an embodiment of the present invention, an electronic circuit includes an element section. The element section includes a first coupler, a first resonator, and a first conductive member. The first coupler can be capacitively coupled to a first qubit and a second qubit. The first coupler includes a loop. The first resonator can be inductively coupled to the loop. The first conductive member can be capacitively coupled to the first resonator. An excitation signal for exciting the first resonator is input to the first conductive member.
Brief Description of the Drawings
[0006] [Figure 1] Figure 1 is a schematic plan view illustrating an electronic circuit according to the first embodiment. [Figure 2] Figure 2 is a schematic plan view illustrating a part of the electronic circuit according to the first embodiment. [Figure 3] Figure 3 is an equivalent circuit illustrating the electronic circuit according to the first embodiment. [Figure 4] Figure 4 is a graph illustrating the characteristics of the electronic circuit according to the first embodiment. [Figure 5] Figures 5(a) to 5(c) are schematic diagrams illustrating an electronic circuit according to the first embodiment. [Figure 6] Figures 6(a) to 6(c) are schematic diagrams illustrating the electronic circuit according to the first embodiment. [Figure 7] Figures 7(a) to 7(c) are schematic diagrams illustrating an electronic circuit according to the first embodiment. [Figure 8] Figure 8 is an equivalent circuit illustrating the electronic circuit according to the first embodiment. [Figure 9] Figures 9(a) to 9(c) are schematic diagrams illustrating the electronic circuit according to the first embodiment. [Figure 10] Figures 10(a) to 10(e) are schematic cross-sectional views illustrating a part of the electronic circuit according to the first embodiment. [Modes for carrying out the invention]
[0007] Embodiments of the present invention will be described below with reference to the drawings. Drawings are schematic or conceptual, and the relationships between the thickness and width of each part, as well as the ratios of the sizes of different parts, are not necessarily identical to those of reality. Even when representing the same part, the dimensions and ratios may differ between drawings. In this specification and in each figure, elements similar to those described above are denoted by the same reference numerals with respect to previously shown figures, and detailed explanations are omitted as appropriate.
[0008] (First Embodiment) Figure 1 is a schematic plan view illustrating an electronic circuit according to the first embodiment. As shown in Figure 1, the electronic circuit 110 according to the embodiment includes an element section 10E. The element section 10E includes a first coupler 10C, a first resonator 21, and a first conductive member 31. The element section 10E may also include a first qubit 51B and a second qubit 52B.
[0009] The first coupler 10C is capacitively coupled to the first qubit 51B and the second qubit 52B. The first coupler 10C includes a loop 10LP.
[0010] The first resonator 21 can be inductively coupled to the loop 10LP (inductive coupling 21I as illustrated in Figure 1). The first conductive member 31 can be capacitively coupled to the first resonator 21 (capacitive coupling 31C as illustrated in Figure 1). An excitation signal Sig1 is input to the first conductive member 31 to excite the first resonator 21.
[0011] For example, a control unit 70 is provided. An excitation signal Sig1 is supplied from the control unit 70 to the first conductive member 31.
[0012] The electronic circuit 110 may be included in the computing device 210. The computing device 210 includes the electronic circuit 110 according to the embodiment and a control unit 70. Calculations can be performed in the computing device 210 including the electronic circuit 110.
[0013] In the electronic circuit 110, the excitation signal Sig1 is supplied to the first resonator 21 by capacitive coupling via the first conductive member 31. This allows the first resonator 21 to resonate, for example, with an AC (high frequency) excitation signal Sig1. Due to the amplification effect of the resonator, for example, the power required for gate operation can be reduced. For example, the DC component of the signal is not supplied to the first resonator 21. This suppresses the intrusion of low-frequency noise. For example, the supply path of the excitation signal Sig1 becomes simpler. For example, it becomes easier to provide multiple element sections 10E at high density. A high-density electronic circuit can be obtained. According to the embodiment, it is possible to provide an electronic circuit and a computing device capable of improving performance.
[0014] For example, there is a reference example in which the excitation signal Sig1 is directly supplied to a wiring connected to the ground. In this reference example, the excitation signal Sig1 is supplied to the wiring without passing through the resonator. In such a reference example, since a large current is required for the gate operation, the power required for the gate operation is large. In the reference example, low-frequency noise is likely to be mixed in. Since the wiring that can be inductively coupled to the loop 10LP is electrically directly connected to the control unit 70, the wiring becomes complicated. For this reason, for example, it is difficult to provide a plurality of element portions 10E with a high density.
[0015] On the other hand, in the embodiment, it becomes easier. The excitation signal Sig1 is supplied to the first resonator 21 by capacitive coupling via the first conductive member 31. The first conductive member 31 can be spatially separated from the first resonator 21. As a result, the degree of freedom in the design of the first conductive member 31 is expanded. A plurality of element portions 10E with a high density can be easily obtained. As will be described later, a three-dimensional configuration is more easily applicable.
[0016] As shown in FIG. 1, in this example, the electronic circuit 110 may include a first substrate 81. The first substrate 81 includes a first surface 81F. A conductive layer 81C is provided on the first surface 81F. For example, the element portion 10E may be formed by the patterned conductive layer 81C.
[0017] One direction along the first surface 81F is defined as the X-axis direction. A direction perpendicular to the X-axis direction along the first surface 81F is defined as the Y-axis direction. A direction perpendicular to the X-axis direction and the Y-axis direction is defined as the Z-axis direction. The first surface 81F is along the X-Y plane. The conductive layer 81C is a layered structure that spreads along the X-Y plane.
[0018] As shown in FIG. 1, the first qubit 51B may include a first bit Josephson junction 51J and a first bit conductive portion 51a. A part 51ap of the first bit conductive portion 51a is connected to the first bit Josephson junction 51J. The other part 51aq of the first bit conductive portion 51a can be capacitively coupled to the first coupler 10C.
[0019] The second qubit 52B may include a second bit Josephson junction 52J and a second bit conductive portion 52a. A portion 52ap of the second bit conductive portion 52a is connected to the second bit Josephson junction 52J. The other portion 52aq of the second bit conductive portion 52a can be capacitively coupled to the first coupler 10C.
[0020] In this example, a first connecting conductive part 11A and a second connecting conductive part 12A are provided. The other part 51aq of the first bit conductive part 51a can be capacitively coupled with the first coupler 10C via the first connecting conductive part 11A. The other part 52aq of the second bit conductive part 52a can be capacitively coupled with the first coupler 10C via the second connecting conductive part 12A.
[0021] As shown in Figure 1, the electronic circuit 110 may further include a magnetic flux control unit 61. The magnetic flux control unit 61 can control the magnetic flux in the space within loop 10LP. The magnetic flux control unit 61 may be included in the computing device 210. For example, the current supplied from the control unit 70 to the magnetic flux control unit 61 includes a DC component. The magnetic field generated by the current passes through the space within loop 10LP. The magnetic flux in the space within loop 10LP can be controlled by the current. The magnetic flux control unit 61 may also be supplied with current from an electronic circuit different from the control unit 70 (such as a current source).
[0022] In this embodiment, multiple element sections 10E may be provided. At least a portion of the multiple element sections 10E are provided on the first base body 81. The magnetic flux control unit 61 may be able to apply a magnetic field to the multiple element sections 10E collectively. For example, the magnetic flux control unit 61 may be able to control the magnetic flux in the space within the loop 10LP included in each of the multiple element sections 10E. This makes the configuration simpler.
[0023] As shown in Figure 1, the electronic circuit 110 may include a reference potential layer 81G. The reference potential layer 81G is formed from a portion of the conductive layer 81C. The reference potential layer 81G is set to, for example, the ground potential GND. For example, the reference potential layer 81G is provided around at least a portion of the first coupler 10C, the first resonator 21, the first conductive member 31, the first qubit 51B, and the second qubit 52B.
[0024] The following describes an example of the first coupler 10C. Figure 2 is a schematic plan view illustrating a part of the electronic circuit according to the first embodiment. As shown in Figure 2, the loop 10LP of the first coupler 10C includes a first coupler Josephson junction 11J, a second coupler Josephson junction 12J, a third coupler Josephson junction 13J, a first coupler conductive part 11a, and a second coupler conductive part 12a.
[0025] The first coupler conductive portion 11a is provided between a portion 11Jp of the first coupler Josephson junction 11J and a portion 13Jp of the third coupler Josephson junction 13J. The first coupler conductive portion 11a is connected to the portion 11Jp of the first coupler Josephson junction 11J and the portion 13Jp of the third coupler Josephson junction 13J. The connection can be an electrical connection.
[0026] The second coupler conductive portion 12a is provided between a portion 12Jp of the second coupler Josephson junction 12J and the other portion 13Jq of the third coupler Josephson junction 13J. The second coupler conductive portion 12a is connected to the portion 12Jp of the second coupler Josephson junction 12J and the other portion 13Jq of the third coupler Josephson junction 13J. The connection can be an electrical connection.
[0027] The other portion 11Jq of the first coupler Josephson junction 11J is connected to the other portion 12Jq of the second coupler Josephson junction 12J. In this example, the reference potential layer 81G electrically connects the other portion 11Jq to the other portion 12Jq.
[0028] The first coupler conductive part 11a can be capacitively coupled to the first qubit 51B. The first coupler conductive part 11a can be capacitively coupled to the first qubit 51B via the first connecting conductive part 11A.
[0029] The second coupler conductive part 12a can be capacitively coupled to the second qubit 52B. The second coupler conductive part 12a can be capacitively coupled to the second qubit 52B via the second connecting conductive part 12A.
[0030] As shown in Figures 1 and 2, the other part 51aq of the first bit conductive part 51a can be capacitively coupled with the first coupler conductive part 11a via the first connecting conductive part 11A. The other part 52aq of the second bit conductive part 52a can be capacitively coupled with the second coupler conductive part 12a via the second connecting conductive part 12A.
[0031] The magnetic flux Φex in the space inside loop 10LP is controlled by the magnetic flux control unit 61 (see Figure 1).
[0032] Figure 3 is an equivalent circuit illustrating the electronic circuit according to the first embodiment. As shown in Figure 3, the first qubit 51B may include a first bit capacitor 51C in addition to the first bit Josephson junction 51J and the first bit conductive part 51a. The first bit capacitor 51C is in parallel with the first bit Josephson junction 51J.
[0033] The second qubit 52B may include a second bit capacitor 52C in addition to the second bit Josephson junction 52J and the second bit conductive part 52a. The second bit capacitor 52C is in parallel with the second bit Josephson junction 52J.
[0034] A first coupler capacitor 11C may be provided in parallel with the first coupler Josephson junction 11J. The first coupler Josephson junction 11J, the first coupler conductive part 11a, and the first coupler capacitor 11C form a first coupler resonator 11T. The first coupler resonator 11T is, for example, a single transmon resonator.
[0035] A second coupler capacitor 12C may be provided in parallel with the second coupler Josephson junction 12J. The second coupler Josephson junction 12J, the second coupler conductive part 12a, and the second coupler capacitor 12C form a second coupler resonator 12T. The second coupler resonator 12T is, for example, a single transmon resonator. The first coupler 10C is, for example, a double transmon coupler. The first coupler 10C is, for example, a tunable coupler.
[0036] As shown in Figure 3, the first qubit 51B and the first coupler conductive part 11a are capacitively coupled by the first capacitor C1. The second qubit 52B and the second coupler conductive part 12a are capacitively coupled by the second capacitor C2.
[0037] A third capacitor C3 may be provided in parallel with the third coupler Josephson junction 13J. A fourth capacitor C4 may be provided between the first bit conductive part 51a and the second coupler conductive part 12a. A fifth capacitor C5 may be provided between the second bit conductive part 52a and the first coupler conductive part 11a. A sixth capacitor C6 may be provided between the first bit conductive part 51a and the second bit conductive part 52a.
[0038] As shown in Figure 3, a first resonator 21 is provided near the loop 10LP of the first coupler 10C. A first conductive member 31 is provided that capacitively couples with the first resonator 21. The control unit 70 supplies an excitation signal Sig1 to the first conductive member 31.
[0039] In the example shown in Figure 3, one end of the first resonator 21 is set to ground potential (GND). The other end of the first resonator 21 may be floating.
[0040] The following describes an example of the operation of the electronic circuit 110 (and the computing device 210). The first qubit 51B has a first bit frequency fb1. The second qubit 52B has a second bit frequency fb2.
[0041] The first qubit 51B has a first state and a second state that is different from the first state. The first bit frequency fb1 is the frequency corresponding to the difference between the first energy in the first state and the second energy in the second state. The second qubit 52B has a third state and a fourth state that is different from the third state. The second bit frequency fb2 is the frequency corresponding to the difference between the third energy in the third state and the fourth energy in the fourth state.
[0042] In this embodiment, the resonance characteristics of the first resonator 21 may be determined according to the first bit frequency fb1 and the second bit frequency fb2.
[0043] Figure 4 is a graph illustrating the characteristics of the electronic circuit according to the first embodiment. Figure 4 illustrates the resonance characteristics of the first resonator 21. The horizontal axis in Figure 4 represents frequency fr0, and the vertical axis represents intensity S0. As shown in Figure 4, the intensity S0 of the resonance characteristics reaches its maximum value Smax at frequency fp0. When frequency fr0 is lower than frequency fp0, intensity S0 decreases as frequency fr0 decreases. When frequency fr0 is higher than frequency fp0, intensity S0 decreases as frequency fr0 increases.
[0044] As shown in Figure 4, the resonance characteristics of the first resonator 21 include a first frequency f1 and a second frequency f2 that is higher than the first frequency f1. At the first frequency f1, the intensity S0 of the resonance characteristic is 0.1 times the maximum value Smax of the resonance characteristic. At the second frequency f2, the intensity S0 of the resonance characteristic is 0.1 times the maximum value Smax.
[0045] Such resonance characteristics depend on the first bit frequency fb1 and the second bit frequency fb2. As shown in Figure 4, the sum frequency frs is the sum of the first bit frequency fb1 and the second bit frequency fb2. The sum frequency frs lies between the first frequency f1 and the second frequency f2. That is, the first frequency f1 is lower than the sum of the first bit frequency fb1 and the second bit frequency fb2 (sum frequency frs). The second frequency f2 is higher than the sum (sum frequency frs).
[0046] This allows, for example, the resonance in the first resonator 21 to be effectively actuated on the first coupler 10C. For example, the first qubit 51B and the second qubit 52B can be effectively controlled.
[0047] For example, oscillations of the |00> and |11> states can be effectively obtained in the first qubit 51B and the second qubit 52B. For example, a two-qubit gate can be executed with two qubits. For example, a two-qubit gate can be executed with 99.99% accuracy in a time of 30ns.
[0048] As shown in Figure 4, the resonance characteristic of the first resonator 21 has a full width at half maximum (FMAX). The lower frequency fhL of the FMAX is lower than the sum (sum frequency frs) of the first bit frequency fb1 and the second bit frequency fb2. The upper frequency fhH of the FMAX is higher than the sum (sum frequency frs). For example, the sum frequency frs is set between the lower frequency fhL and the upper frequency fhH of the FMAX. At the lower frequency fhL and the upper frequency fhH, the intensity S0 of the resonance characteristic is 0.5 times the maximum value Smax. The upper frequency fhH is higher than the lower frequency fhL.
[0049] For example, the frequency fp0 at which the intensity S0 is maximum can be substantially the same as the sum frequency frs.
[0050] For example, an excitation signal Sig1 with a frequency that matches the resonance characteristics of the first resonator 21 is supplied from the control unit 70 to the first conductive member 31. This allows the first resonator 21 to resonate with high efficiency.
[0051] For example, the excitation signal Sig1 includes a pulse with the first bit frequency fb1 of the first qubit 51B, the second bit frequency fb2 of the second qubit 52B, and the sum frequency (sum frequency frs).
[0052] For example, the control unit 70 can execute a two-qubit gate relating to the first qubit 51B and the second qubit 52B by supplying an excitation signal Sig1 (e.g., a pulse) to the first conductive member 31. The frequency of the excitation signal Sig1 is between a first frequency f1 and a second frequency f2. The frequency of the excitation signal Sig1 is between a lower frequency fhL and an upper frequency fhH.
[0053] For example, the resonant frequency of the first coupler resonator 11T, which includes the first coupler Josephson junction 11J and the first coupler conductive part 11a, is defined as the first coupler resonant frequency. The first coupler resonant frequency is higher than the first bit frequency fb1, higher than the second bit frequency fb2, and lower than the sum frequency frs. The resonant frequency of the second coupler resonator 12T, which includes the second coupler Josephson junction 12J and the second coupler conductive part 12a, is defined as the second coupler resonant frequency. The second coupler resonant frequency is higher than the first bit frequency fb1, higher than the second bit frequency fb2, and lower than the sum frequency frs.
[0054] In one example, the first bit frequency fb1 is, for example, 5.0 GHz. The second bit frequency fb2 is, for example, 5.3 GHz. The sum frequency frs is, for example, 10.3 GHz. The first coupler resonant frequency of the first coupler resonator 11T is, for example, 7.0 GHz. The second coupler resonant frequency of the second coupler resonator 12T is, for example, 7.0 GHz.
[0055] The following describes some examples of the configuration of the element section 10E. Figures 5(a) to 5(c) are schematic diagrams illustrating an electronic circuit according to the first embodiment. Figures 5(a) and 5(b) are plan views. Figure 5(c) is a cross-sectional view taken along line A1-A2 in Figures 5(a) and 5(b).
[0056] As shown in Figure 5(a), the electronic circuit 111 according to this embodiment includes a first substrate 81. As shown in Figure 5(b), the electronic circuit 111 includes a second substrate 82. As shown in Figure 5(c), the first substrate 81 and the second substrate 82 are stacked on top of each other in the Z-axis direction.
[0057] As shown in Figures 5(a) and 5(c), the first substrate 81 includes a first surface 81F. As shown in Figures 5(b) and 5(c), the second substrate 82 includes a second surface 82F. The direction from the first substrate 81 to the second substrate 82 intersects with the first surface 81F and the second surface 82F.
[0058] As shown in Figure 5(c), at least a portion of the second surface 82F faces at least a portion of the first surface 81F. In the electronic circuit 111, the first coupler 10C and the first resonator 21 are provided on the first surface 81F. The first conductive member 31 is provided on the second surface 82F. At least a portion of the first resonator 21 (and / or the conductive film connected to the first resonator 21) faces at least a portion of the first conductive member 31 (and / or the conductive film connected to the first conductive member 31). The first conductive member 31 is capacitively coupled to the first resonator 21.
[0059] As shown in Figure 5(b), a conductive layer 82C is provided on the second surface 82F. A portion of the conductive layer 82C becomes the first conductive member 31. A portion of the conductive layer 82C may also become the reference potential layer 82G. The reference potential layer 82G is set to, for example, the ground potential GND. The reference potential layer 82G is provided around the first conductive member 31.
[0060] In the electronic circuit 111, a portion of the element portion 10E is provided on the first substrate 81, and another portion of the element portion 10E is provided on the second substrate 82. This simplifies the configuration and makes it easier to achieve a high degree of integration.
[0061] In the electronic circuit 111, a portion of the first resonator 21 is capacitively coupled to the first conductive member 31. The other portion of the first resonator 21 is connected to the reference potential layer 81G.
[0062] Figures 6(a) to 6(c) are schematic diagrams illustrating the electronic circuit according to the first embodiment. Figures 6(a) and 6(b) are plan views. Figure 6(c) is a cross-sectional view taken along line A1-A2 in Figures 6(a) and 6(b).
[0063] As shown in Figures 6(a) and 6(b), the electronic circuit 112 according to this embodiment includes a first substrate 81 and a second substrate 82. As shown in Figure 6(c), at least a portion of the second surface 82F faces at least a portion of the first surface 81F. The first coupler 10C is provided on the first surface 81F. The first resonator 21 and the first conductive member 31 are provided on the second surface 82F. The configuration of the electronic circuit 112 is simplified. High integration density is easily achieved.
[0064] In the electronic circuit 112, a portion of the first resonator 21 is capacitively coupled to the first conductive member 31. The other portion of the first resonator 21 is connected to the reference potential layer 82G.
[0065] Figures 7(a) to 7(c) are schematic diagrams illustrating an electronic circuit according to the first embodiment. Figure 8 is an equivalent circuit illustrating the electronic circuit according to the first embodiment. Figures 7(a) and 7(b) are plan views. Figure 7(c) is a cross-sectional view taken along line A1-A2 in Figures 7(a) and 7(b). As shown in Figures 7(a) and 7(b), the electronic circuit 113 according to the embodiment includes a first substrate 81 and a second substrate 82. The first coupler 10C and the first resonator 21 are provided on the first surface 81F. The first conductive member 31 is provided on the second surface 82F. In the electronic circuit 113, the first resonator 21 is floating. As shown in Figure 8, in the electronic circuit 113, the first resonator 21 may be capacitively coupled to a reference potential layer 81G.
[0066] Figures 9(a) to 9(c) are schematic diagrams illustrating the electronic circuit according to the first embodiment. Figures 9(a) and 9(b) are plan views. Figure 9(c) is a cross-sectional view taken along line A1-A2 in Figures 9(a) and 9(b). As shown in Figures 9(a) and 9(b), the electronic circuit 114 according to the embodiment includes a first substrate 81 and a second substrate 82. The first coupler 10C is provided on the first surface 81F. The first resonator 21 and the first conductive member 31 are provided on the second surface 82F. In the electronic circuit 114, the first resonator 21 is floating. Similar to the electronic circuit 113, in the electronic circuit 114, the first resonator 21 may be capacitively coupled to a reference potential layer 81G (see Figure 8).
[0067] In electronic circuits 111-114, at least a portion of the first resonator 21 does not need to overlap with the loop 10LP in the direction from the first substrate 81 to the second substrate 82 (Z-axis direction). This makes it easier to obtain effective inductive coupling.
[0068] In the electronic circuits 110 to 114 according to the embodiment, the first qubit 51B and the second qubit 52B may be provided on the first surface 81F.
[0069] In electronic circuits 111 to 114, a magnetic flux control unit 61 may be provided in addition to the element unit 10E. In the above diagram relating to electronic circuits 111 to 114, the magnetic flux control unit 61 is omitted.
[0070] The following is an example of a Josephson junction. Figures 10(a) to 10(e) are schematic cross-sectional views illustrating a part of the electronic circuit according to the first embodiment. As shown in Figure 10(a), in the first bit Josephson junction 51J, conductive films 85a and 85b are oriented onto the first surface 81F of the first substrate 81. An insulating film 86a is provided between a portion of conductive film 85a and a portion of conductive film 85b.
[0071] As shown in Figure 10(b), in the second bit Josephson junction 52J, the conductive film 85c and conductive film 85d are oriented onto the first surface 81F of the first substrate 81. An insulating film 86b is provided between a portion of the conductive film 85c and a portion of the conductive film 85d.
[0072] As shown in Figure 10(c), in the first coupler Josephson junction 11J, the conductive film 85e and the conductive film 85f are oriented onto the first surface 81F of the first substrate 81. An insulating film 86c is provided between a portion of the conductive film 85e and a portion of the conductive film 85f.
[0073] As shown in Figure 10(d), in the second coupler Josephson junction 12J, the conductive film 85g and conductive film 85h are oriented onto the first surface 81F of the first substrate 81. An insulating film 86d is provided between a portion of the conductive film 85g and a portion of the conductive film 85h.
[0074] As shown in Figure 10(e), in the third coupler Josephson junction 13J, the conductive films 85i and 85j are oriented onto the first surface 81F of the first substrate 81. An insulating film 86e is provided between a portion of the conductive film 85i and a portion of the conductive film 85j.
[0075] (Second Embodiment) The second embodiment is a computing device 210 (see Figure 1, etc.). The computing device 210 includes the electronic circuits according to the first embodiment (for example, electronic circuits 110 to 114 and their variations) and a control unit 70. The control unit 70 is capable of supplying an excitation signal Sig1 to the first conductive member 31. For example, a computing device with a high degree of integration can be provided.
[0076] In the computing device 210, for example, the control unit 70 can execute a two-qubit gate relating to the first qubit 51B and the second qubit 52B by supplying an excitation signal Sig1 to the first conductive member 31.
[0077] The embodiment may include the following configuration (e.g., proposed technical details). (Composition 1) A first coupler capacitively coupled to a first qubit and a second qubit, wherein the first coupler includes a loop, A first resonator that can be inductively coupled to the aforementioned loop, A first conductive member capacitively coupled to the first resonator, wherein an excitation signal for exciting the first resonator is input to the first conductive member, An electronic circuit comprising an element section including such elements.
[0078] (Configuration 2) The first qubit has a first bit frequency, The second qubit has a second bit frequency, The resonance characteristics of the first resonator include a first frequency and a second frequency that is higher than the first frequency. At the first frequency, the intensity of the resonance characteristic is 0.1 times the maximum value of the resonance characteristic. At the second frequency, the intensity of the resonance characteristic is 0.1 times the maximum value. The first frequency is lower than the sum of the first bit frequency and the second bit frequency. The electronic circuit described in Configuration 1, wherein the second frequency is higher than the sum of the frequencies.
[0079] (Composition 3) The first qubit has a first bit frequency, The second qubit has a second bit frequency, The lower frequency of the full width at half maximum of the resonance characteristic of the first resonator is lower than the sum of the first bit frequency and the second bit frequency. The electronic circuit described in Configuration 1, wherein the upper frequency of the full bandwidth at half maximum is higher than the sum of the above.
[0080] (Composition 4) The first qubit has a first state and a second state that is different from the first state. The first bit frequency is the frequency corresponding to the difference between the first energy in the first state and the second energy in the second state. The second qubit has a third state and a fourth state that is different from the third state, The electronic circuit according to configuration 2 or 3, wherein the second bit frequency is a frequency corresponding to the difference between the third energy in the third state and the fourth energy in the fourth state.
[0081] (Composition 5) A first substrate including the first face, A second substrate including the second face, Furthermore, At least a portion of the second surface faces at least a portion of the first surface, The first coupler and the first resonator are provided on the first surface, The first conductive member is an electronic circuit provided on the second surface, according to any one of configurations 1 to 4.
[0082] (Composition 6) A first substrate including the first face, A second substrate including the second face, Furthermore, At least a portion of the second surface faces at least a portion of the first surface, The first coupler is provided on the first surface, The first resonator and the first conductive member are provided on the second surface, and are an electronic circuit according to any one of configurations 1 to 4.
[0083] (Composition 7) At least a portion of the first resonator is an electronic circuit according to configuration 5 or 6, which does not overlap with the loop in the direction from the first substrate to the second substrate.
[0084] (Composition 8) The aforementioned loop is First coupler Josephson joint, The second coupler-Josephson joint, Third coupler Josephson joint, The first coupler conductive portion between a part of the first coupler Josephson junction and a part of the third coupler Josephson junction, The second coupler conductive portion between a part of the second coupler Josephson joint and the other part of the third coupler Josephson joint, Includes, The other part of the first coupler Josephson joint is connected to the other part of the second coupler Josephson joint. The first coupler conductive portion is capacitively coupled to the first qubit, The electronic circuit according to any one of configurations 1 to 7, wherein the second coupler conductive portion is capacitively coupled to the second qubit.
[0085] (Composition 9) The element further includes the first qubit and the second qubit, The first qubit includes a first bit Josephson junction and a first bit conductive portion. A portion of the first bit conductive part is connected to the first bit Josephson junction, The other part of the first bit conductive part is capacitively coupled to the first coupler conductive part. The second qubit includes a second bit Josephson junction and a second bit conductive portion. A portion of the second bit conductive part is connected to the second bit Josephson junction, The electronic circuit according to configuration 8, wherein the other part of the second bit conductive part is capacitively coupled with the second coupler conductive part.
[0086] (Composition 10) The aforementioned loop is First coupler Josephson joint, The second coupler-Josephson joint, Third coupler Josephson joint, The first coupler conductive portion between a part of the first coupler Josephson junction and a part of the third coupler Josephson junction, The second coupler conductive portion between a part of the second coupler Josephson joint and the other part of the third coupler Josephson joint, Includes, The other part of the first coupler Josephson joint is connected to the other part of the second coupler Josephson joint. The first coupler conductive portion is capacitively coupled to the first qubit, The second coupler conductive portion is capacitively coupled to the second qubit, The first coupler resonant frequency of the first coupler resonator, which includes the first coupler Josephson junction and the first coupler conductive portion, is higher than the first bit frequency, higher than the second bit frequency, and lower than the sum of the two bits. The electronic circuit according to configuration 2 or 3, wherein the second coupler resonant frequency of the second coupler resonator, which includes the second coupler Josephson junction and the second coupler conductive portion, is higher than the first bit frequency, higher than the second bit frequency, and lower than the sum of the two bits.
[0087] (Composition 11) The electronic circuit according to any one of configurations 1 to 9, further comprising a magnetic flux control unit capable of controlling the magnetic flux in the space within the loop.
[0088] (Composition 12) Multiple of the element sections are provided, The magnetic flux control unit is capable of controlling the magnetic flux in the space within the loop included in each of the plurality of element sections, as described in configuration 11.
[0089] (Composition 13) The electronic circuit described in Configuration 1, A control unit capable of supplying the excitation signal to the first conductive member, A computing device equipped with a computer.
[0090] (Composition 14) The first qubit has a first bit frequency, The second qubit has a second bit frequency, The resonance characteristics of the first resonator include a first frequency and a second frequency that is higher than the first frequency. At the first frequency, the intensity of the resonance characteristic is 0.1 times the maximum value of the resonance characteristic. At the second frequency, the intensity of the resonance characteristic is 0.1 times the maximum value. The first frequency is lower than the sum of the first bit frequency and the second bit frequency. The second frequency is higher than the sum, The calculation device according to configuration 13, wherein the excitation signal includes pulses with the frequency of the sum.
[0091] (Composition 15) The first qubit has a first bit frequency, The second qubit has a second bit frequency, The lower frequency of the full width at half maximum of the resonance characteristic of the first resonator is lower than the sum of the first bit frequency and the second bit frequency. The upper frequency of the full bandwidth at half maximum is higher than the sum of the above. The calculation device according to configuration 13, wherein the excitation signal includes pulses with the frequency of the sum.
[0092] (Composition 16) The computing apparatus according to configuration 14 or 15, wherein the control unit can execute a two-qubit gate relating to the first qubit and the second qubit by supplying the excitation signal to the first conductive member.
[0093] (Composition 17) The computing device according to any one of configurations 13 to 16, further comprising a magnetic flux control unit capable of controlling the magnetic flux in the space within the loop.
[0094] According to the embodiment, an electronic circuit and computing device capable of improving performance can be provided.
[0095] Embodiments of the present invention have been described above with reference to examples. However, the present invention is not limited to these examples. For example, the specific configuration of each element such as qubits, couplers, resonators, conductive members, Josephson junctions, and capacitors included in an electronic circuit or computing device is included within the scope of the present invention as long as those skilled in the art can appropriately select from the known scope to implement the present invention in a similar manner and obtain similar effects.
[0096] Combinations of two or more elements from each example, to the extent technically feasible, are also included within the scope of the present invention, insofar as they encompass the gist of the invention.
[0097] All electronic circuits and computing devices that a person skilled in the art can design and implement based on the electronic circuits and computing devices described above as embodiments of the present invention also fall within the scope of the present invention, insofar as they encompass the gist of the present invention.
[0098] Within the scope of the concept of this invention, a person skilled in the art would be able to conceive of various modifications and alterations, and it is understood that such modifications and alterations also fall within the scope of this invention.
[0099] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]
[0100] 10C: First coupler, 10E: Element part, 10LP: Loop, 11A, 12A: First and second connecting conductive parts, 11C, 12C: First and second coupler capacitors, 11J~13J: First to third coupler Josephson junctions, 11Jp~13Jp: Part, 11Jq~13Jq: Other parts, 11T, 12T: First and second coupler resonators, 11a, 12a: First and second coupler conductive parts, 21: First resonator, 21I: Inductive coupling, 31: First conductive member, 31C: Capacitive coupling, 51B, 52B: First and second qubits, 51C, 52C: First and second bit capacitors, 51J, 52J: First and second bit Josephson junctions, 51a, 52a: 1st and 2nd bit conductive parts, 51ap, 52ap: part, 51aq, 52aq: other parts, 61: magnetic flux control unit, 70: control unit, 81, 82: 1st and 2nd substrates, 81C, 82C: conductive layer, 81F, 82F: 1st and 2nd surfaces, 81G, 82G: reference potential layer, 85a~85j: conductive film, 86a~86e: insulating film, 110~114: electronic circuit, 210: computing device, C1~C6: 1st to 6th capacitors, GND: ground potential, S0: intensity, Sig1: excitation signal, Smax: maximum value, f1, f2: 1st and 2nd frequencies, fhH: upper frequency, fhL: lower frequency, fp0, fr0: frequency, Φex: magnetic flux
Claims
1. A first coupler capacitively coupled to a first qubit and a second qubit, wherein the first coupler includes a loop, A first resonator that can be inductively coupled to the aforementioned loop, A first conductive member capacitively coupled to the first resonator, wherein an excitation signal for exciting the first resonator is input to the first conductive member, An electronic circuit comprising an element section including such elements.
2. The first qubit has a first bit frequency, The second qubit has a second bit frequency, The resonance characteristics of the first resonator include a first frequency and a second frequency that is higher than the first frequency. At the first frequency, the intensity of the resonance characteristic is 0.1 times the maximum value of the resonance characteristic. At the second frequency, the intensity of the resonance characteristic is 0.1 times the maximum value. The first frequency is lower than the sum of the first bit frequency and the second bit frequency. The electronic circuit according to claim 1, wherein the second frequency is higher than the sum.
3. A first substrate including the first face, A second substrate including the second face, Furthermore, At least a portion of the second surface faces at least a portion of the first surface, The first coupler and the first resonator are provided on the first surface, The first conductive member is provided on the second surface, and is part of the electronic circuit according to claim 1 or 2.
4. A first substrate including the first face, A second substrate including the second face, Furthermore, At least a portion of the second surface faces at least a portion of the first surface, The first coupler is provided on the first surface, The first resonator and the first conductive member are provided on the second surface, as described in claim 1 or 2.
5. The aforementioned loop is The first coupler-Josephson joint, The second coupler Josephson joint, Third coupler Josephson joint, The first coupler conductive portion between a part of the first coupler Josephson junction and a part of the third coupler Josephson junction, The second coupler conductive portion between a part of the second coupler Josephson joint and the other part of the third coupler Josephson joint, Includes, The other part of the first coupler Josephson joint is connected to the other part of the second coupler Josephson joint. The first coupler conductive portion is capacitively coupled to the first qubit, The electronic circuit according to claim 1, wherein the second coupler conductive portion is capacitively coupled to the second qubit.
6. The element further includes the first qubit and the second qubit, The first qubit includes a first bit Josephson junction and a first bit conductive portion. A portion of the first bit conductive part is connected to the first bit Josephson junction, The other part of the first bit conductive part is capacitively coupled to the first coupler conductive part. The second qubit includes a second bit Josephson junction and a second bit conductive portion. A portion of the second bit conductive part is connected to the second bit Josephson junction, The electronic circuit according to claim 5, wherein the other part of the second bit conductive part is capacitively coupled with the second coupler conductive part.
7. The electronic circuit described in claim 1, A control unit capable of supplying the excitation signal to the first conductive member, A computing device equipped with a computer.
8. The first qubit has a first bit frequency, The second qubit has a second bit frequency, The resonance characteristics of the first resonator include a first frequency and a second frequency that is higher than the first frequency. At the first frequency, the intensity of the resonance characteristic is 0.1 times the maximum value of the resonance characteristic. At the second frequency, the intensity of the resonance characteristic is 0.1 times the maximum value. The first frequency is lower than the sum of the first bit frequency and the second bit frequency. The second frequency is higher than the sum, The calculation device according to claim 7, wherein the excitation signal includes pulses having the frequency of the sum.
9. The computing apparatus according to claim 8, wherein the control unit can execute a two-qubit gate relating to the first qubit and the second qubit by supplying the excitation signal to the first conductive member.
10. The computing device according to claim 7, further comprising a magnetic flux control unit capable of controlling the magnetic flux in the space within the loop.