A quantum bit regulation circuit, a quantum chip and a quantum computer

Abstract

The application discloses a quantum bit regulation circuit, a quantum chip and a quantum computer, and relates to the field of quantum chip control. Based on different frequency ranges, an external signal generator can output an electric signal including low-frequency control information and / or high-frequency control information to a control matching part through a first integrated control line by using only one control channel; the control matching part couples the electric signal including high-frequency control information with a cross capacitor to make the equivalent coupling capacitance value of the quantum bit equal to a target coupling capacitance value, and / or couples the electric signal including low-frequency control information with a superconducting quantum interference device to form a magnetic field to make the working frequency of the quantum bit equal to a target working frequency. In the case of only one control channel, the control matching part realizes the driving and frequency regulation of the quantum bit, reduces the control channel, provides convenience for the setting of a measurement and control channel, is beneficial to the wiring design and packaging of the quantum chip, and is beneficial to integrated design.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of quantum chip control, in particular to a quantum bit regulation circuit, a quantum chip and a quantum computer. BACKGROUND

[0002] A quantum chip is to integrate quantum bits and related circuits on a substrate, and then carry the function of quantum information processing. Usually, a quantum chip includes multiple quantum bits. A quantum bit includes a cross-capacitor and a resonant cavity. In order to realize the driving of the quantum bit, two kinds of control regulation circuits for control are usually relied on in the prior art. The first kind is an XY control line (usually in the form of a coaxial line) of a microwave signal, and the second kind is a Z control line (usually in the form of a coaxial line) of a magnetic signal. Specifically, the XY control line is a signal, which is usually arranged at a position about 50 microns away from the cross-capacitor; the Z control line is another signal, which is usually arranged at a position within 10 microns away from the cross-capacitor; please refer to Figure 1 , Figure 1 is a structural schematic diagram of a quantum chip in the prior art, wherein one quantum bit is taken as an example, Figure 1 The dilution refrigerator in the prior art is used for refrigeration processing to ensure that the temperature of the quantum chip meets the requirement of extremely low temperature. It can be seen that in the prior art, the XY control line and the Z control line respectively occupy two control channels to realize the driving and frequency regulation of the quantum bit, and due to the special requirements for the driving and frequency regulation of the quantum bit, the regulation circuit can only be designed in the form of occupying two output channels at present.

[0003] In addition, please continue to refer to Figure 1 In actual application, in order to realize the measurement and control of the working performance of the quantum bit, an additional measurement and control channel is also needed to connect low-temperature measurement and control instruments. As can be known from the above, at least three control channels are needed for one quantum bit to communicate with the outside to realize the work. Referring to the development history of the traditional computer, after overcoming the bottleneck technology, the research on the quantum computer using the quantum chip inevitably faces the problem of integration in order to realize commercialization and industrial upgrading. When the integration and large-scale design of the quantum chip including multiple quantum bits are faced, the above-mentioned arrangement mode of the regulation circuit of the quantum bit occupies too many control channels, especially when the number of quantum bits is large, which is not conducive to the wiring design and packaging of the quantum chip, and is not conducive to the integrated design.

[0004] Therefore, how to provide a solution to the above technical problems is a problem that those skilled in the art need to solve at present. SUMMARY

[0005] The application aims to provide a quantum bit regulation circuit, a quantum chip and a quantum computer, in which only one control channel is needed for external control, and the driving and frequency regulation of the quantum bit are realized by cooperating with a control matching part, the reduced control channel facilitates the setting of a measurement and control channel, and is beneficial to the wiring design and packaging of the quantum chip and the integrated design.

[0006] To solve the above technical problems, the application provides a quantum bit regulation circuit applied to a quantum chip, wherein the quantum chip comprises a quantum bit, and the quantum bit comprises a cross capacitor and a resonant cavity, and the cross capacitor comprises a superconducting quantum interference device.

[0007] A first integrated control line is connected with an output end of a signal generator arranged outside the quantum chip and a first end of a control matching part arranged inside the quantum chip, and is used for outputting an electric signal output by the signal generator to the control matching part, wherein the electric signal comprises low-frequency control information and / or high-frequency control information.

[0008] The control matching part has a second end connected with the ground, and is used for coupling the received electric signal comprising the high-frequency control information with the cross capacitor, so that the equivalent coupling capacitance value of the quantum bit is equal to a target coupling capacitance value, and / or coupling the received electric signal comprising the low-frequency control information with the superconducting quantum interference device to form a magnetic field, so that the working frequency of the quantum bit is equal to a target working frequency.

[0009] Preferably, when the quantum chip is a single-layer structure;

[0010] The quantum bit and the quantum bit regulation circuit are located in the same layer.

[0011] The cross capacitor comprises a first part and a second part perpendicular to each other, and the quantum bit regulation circuit and the resonant cavity are arranged at diagonal positions of the first part and the second part.

[0012] Preferably, the control matching part comprises a first control line and a second control line.

[0013] The first end of the first control line is separated from the first part of the cross capacitor by a first preset distance and separated from the second part of the cross capacitor by a second preset distance, and is used for coupling the received electric signal comprising the high-frequency control information with the cross capacitor, so that the equivalent coupling capacitance value of the quantum bit is equal to a target coupling capacitance value.

[0014] The first end of the second control line is separated from the first part by a third preset distance and separated from the second part by a fourth preset distance, for coupling the received electrical signal including the low-frequency control information with the superconducting quantum interference device to form a magnetic field, so that the working frequency of the quantum bit is equal to the target working frequency.

[0015] The third preset distance is less than the first preset distance, the tail end of the second control line is connected with the tail end of the first control line, and the common end connected is connected with the first integrated control line.

[0016] Preferably, the control matching part comprises:

[0017] The second integrated control line is connected with the first integrated control line at the first end, and the second end of the second integrated control line is separated from the first part of the cross-capacitor by a fifth preset distance and separated from the second part of the cross-capacitor by a sixth preset distance. The fifth preset distance and the sixth preset distance are preset distances that satisfy the capacitor regulation condition, and the capacitor regulation condition is that the equivalent coupling capacitance value of the quantum bit is equal to the target coupling capacitance value when receiving the electrical signal including the high-frequency control information.

[0018] The first end of the second integrated control line is connected with the second end of the second integrated control line, and the second end of the ground branch is grounded, for regulating the coupling mutual inductance value between the received electrical signal including the low-frequency control information and the superconducting quantum interference device, so that the working frequency of the quantum bit is equal to the target working frequency.

[0019] Preferably, the ground branch is a first bending branch with at least one right angle.

[0020] Preferably, when the quantum chip is a double-layer structure;

[0021] The first integrated control line and the control matching part are located on the first layer of the quantum chip.

[0022] The cross-capacitor and the resonant cavity are located on the second layer of the quantum chip.

[0023] Preferably, the first layer and the second layer are separated by a preset interlayer distance; the control matching part comprises:

[0024] A third body control line, a first end of which is connected to the first body control line, a target end of a projection of the second layer of the third body control line is separated from the first part of the cross-capacitor by a seventh preset distance, and the target end is separated from the second part of the cross-capacitor by an eighth preset distance; wherein the seventh preset distance and the eighth preset distance are preset distances that satisfy a capacitor regulation condition in the presence of the preset layer spacing, and the capacitor regulation condition is that when an electrical signal including the high-frequency control information is received, the equivalent coupling capacitance value of the quantum bit is equal to the target coupling capacitance value.

[0025] A coupling area amplification component, a first end of which is connected to a second end of the third body control line, and a second end of the coupling area amplification component is grounded, for regulating the coupling mutual inductance value between the received electrical signal including the low-frequency control information and the superconducting quantum interference device, so that the operating frequency of the quantum bit is equal to the target operating frequency.

[0026] Preferably, the coupling area amplification component is a fourth body control line in a spiral shape.

[0027] Preferably, the coupling area amplification component is a second bending branch with at least one right angle.

[0028] To solve the above technical problems, the application further provides a quantum chip, comprising a quantum bit, and further comprising the quantum bit regulation line as described above; wherein the quantum bit comprises a cross-capacitor and a resonant cavity, and the cross-capacitor comprises a superconducting quantum interference device.

[0029] To solve the above technical problems, the application further provides a quantum computer, comprising the quantum chip as described above.

[0030] The application provides a quantum bit control circuit, a quantum chip and a quantum computer. The quantum bit control circuit comprises a first integrated control line and a control matching part. The first integrated control line is connected with an output end of a signal generator arranged outside the quantum chip and a first end of the control matching part arranged inside the quantum chip. Due to different frequency ranges, the external signal generator only needs one control channel to output an electric signal comprising low-frequency control information and / or high-frequency control information to the control matching part through the first integrated control line. Then, the control matching part couples the received electric signal comprising high-frequency control information with a cross-capacitance to make an equivalent coupling capacitance value of the quantum bit equal to a target coupling capacitance value, and / or couples the received electric signal comprising low-frequency control information with a superconducting quantum interference device to form a magnetic field to make an operating frequency of the quantum bit equal to a target operating frequency. In the case of only one control channel to the outside, the control matching part is used to realize the driving and frequency control of the quantum bit, which facilitates the setting of the measurement and control channel, and is beneficial to the wiring design and packaging of the quantum chip and the integrated design. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the prior art and the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0032] Figure 1 It is a structural schematic diagram of a quantum chip in the prior art.

[0033] Figure 2 It is a structural schematic diagram of a quantum bit control circuit provided by the present application.

[0034] Figure 3 It is a structural schematic diagram of another quantum bit control circuit provided by the present application.

[0035] Figure 4 It is a structural schematic diagram of another quantum bit control circuit provided by the present application.

[0036] Figure 5 It is a structural schematic diagram of another quantum bit control circuit provided by the present application.

[0037] Figure 6 It is a structural schematic diagram of another quantum bit control circuit provided by the present application.

[0038] Figure 7 It is a structural schematic diagram of another quantum bit control circuit provided by the present application.

[0039] Figure 8 An equivalent circuit diagram of a whole quantum bit under the action of an electrical signal output by a quantum bit control line is provided. DETAILED DESCRIPTION

[0040] The core of the present application is to provide a quantum bit control line, a quantum chip and a quantum computer. In the case of only one control channel to the outside, the driving of the quantum bit and the frequency control are realized by cooperating with the control matching part, the control channel is reduced to facilitate the setting of the measurement and control channel, and the wiring design and packaging of the quantum chip are facilitated, and the integrated design is facilitated.

[0041] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0042] Please refer to Figure 2 , Figure 2 A structure schematic diagram of a quantum bit control line is provided.

[0043] The quantum bit control line is applied to a quantum chip 1, the quantum chip 1 includes a quantum bit, the quantum bit includes a cross-capacitor 12 and a resonant cavity, the cross-capacitor 12 includes a superconducting quantum interference device 123, and the quantum bit control line includes:

[0044] A first combination control line 31 is connected with the output end of a signal generator 2 arranged outside the quantum chip 1 and the first end of a control matching part 32 arranged inside the quantum chip 1 respectively, for outputting the electrical signal output by the signal generator 2 to the control matching part 32, the electrical signal being an electrical signal including low-frequency control information and / or high-frequency control information;

[0045] The control matching part 32 is grounded at the second end, for coupling the received electrical signal including the high-frequency control information with the cross-capacitor 12, so that the equivalent coupling capacitance value of the quantum bit is equal to the target coupling capacitance value, and / or coupling the received electrical signal including the low-frequency control information with the superconducting quantum interference device 123 to form a magnetic field, so that the working frequency of the quantum bit is equal to the target working frequency.

[0046] In this embodiment, considering that a quantum chip includes multiple quantum bits, each quantum bit usually needs to pass through an XY control line (i.e., the above-mentioned microwave drive line), a Z control line (i.e., the above-mentioned magnetic flux control line), and a measurement and control channel; more specifically, the XY control line is usually located at a position about 50 microns away from the cross capacitor to avoid bit decoherence; the Z control line is located at a position within about 10 microns of the cross capacitor to avoid the magnetic field generated when it is coupled to the mutual inductance of the Superconducting Quantum Interference Device (SQUID) being too weak. It can be seen that the setting positions of the two control lines are limited by the special requirements for driving and frequency regulation of the quantum bit, and at present, the control line can only be designed in the form of occupying two output channels. Therefore, at least three control channels are needed for a quantum bit to communicate with the outside of the quantum chip to realize work, so that when facing the integration and large-scale design of a quantum chip including multiple quantum bits, the above-mentioned quantum bit control line arrangement occupies too many control channels, especially when the number of quantum bits is large, which is not conducive to integrated design. To solve the above technical problems, the present application provides a quantum bit control line, which is more conducive to realizing the wiring design and packaging of a quantum chip.

[0047] Specifically, the quantum chip 1 can include a plurality of quantum bits, and each quantum bit corresponds to a set of quantum bit control lines described above in the application for driving and frequency control of the quantum bit. Considering that the relative position design of the XY control line and the cross capacitor 12 is only to ensure that the coupling with the quantum bit reaches the preset function as much as possible, and the relative position design of the Z control line and the cross capacitor 12 is only to ensure that the coupling mutual inductance with the quantum bit reaches the preset function as much as possible, therefore, from the design, the application only needs one control channel outside, that is, using the first integrated control line 31, the input end of the first integrated control line 31 is connected with the output end of the signal generator 2 arranged outside the quantum chip 1, the output end of the first integrated control line 31 is connected with the first end of the control matching part 32, and the first integrated control line 31 can be a wideband microwave transmission line, that is, a coaxial line; the control matching part 32 is specifically arranged at an intermediate position away from the cross capacitor 12 by a certain distance, and the intermediate position is a position that can ensure that the electrical signal transmitted by the first integrated control line 31 realizes the coupling and coupling mutual inductance between the quantum bit to reach the target function; in detail, the second end of the control matching part 32 is grounded, and the electrical signal is either an electrical signal including low-frequency control information, such as a current signal with a lower frequency (i.e., a Z control signal); or an electrical signal including high-frequency control information, such as a voltage signal with a higher frequency (i.e., an XY control signal); or an electrical signal including low-frequency control information and high-frequency control information (since the frequency range corresponds to different, the mixed frequency signal can naturally be realized), then the electrical signal is transmitted by the control matching part 32 to the quantum bit coupling, the quantum bit includes the cross capacitor 12 and the resonant cavity, the cross capacitor 12 includes a superconducting quantum interference device 123, and the superconducting quantum interference device 123 is a 3-JJ structure composed of three Josephson junctions. In the quantum bit, the physical form of the coupling energy coupled with the quantum bit is an electric field or a magnetic field (or a combination thereof), the control matching part 32 does not need to be in direct contact with the cross capacitor 12, but only needs to keep the electrical signal in its vicinity, relying on the electromagnetic coupling characteristic, the target coupling capacitor value ensuring the driving of the quantum bit and the target coupling mutual inductance value ensuring the coupling mutual inductance when the frequency of the quantum bit is adjusted are calculated in advance, when the control matching part 32 receives the electrical signal including high-frequency control information, the electrical signal will be coupled with the cross capacitor 12, so that the equivalent coupling capacitor value of the quantum bit is equal to the target coupling capacitor value, thereby realizing the driving and excitation of the quantum bit, and the quantum bit is transitioned from the ground state to the excited state.When the control matching unit 32 receives an electrical signal including low-frequency control information, this electrical signal couples and mutually inducts with the superconducting quantum interference device 123 in the cross capacitor 12. The electric field generates a corresponding magnetic field in the superconducting quantum interference device 123, causing mutual inductance between the electrical signal and the superconducting quantum interference device 123 and generating a target magnetic flux within the device. This aims to obtain more magnetic flux within the maximum electrical signal range, maximizing the mutual inductance to obtain at least one magnetic flux quantum, achieving the target coupling mutual inductance value so that the operating frequency of the quantum bit equals the target operating frequency. Thus, relying on the first combined control line 31 and the control matching unit 32, the functions of the XY and Z control lines in the prior art are simultaneously realized through electromagnetic coupling characteristics, meeting the design requirements. It should be noted that the frequency corresponding to the high-frequency control information is the target operating frequency.

[0048] For further details, please refer to Figure 2 For example, Figure 2 Let's take one qubit on quantum chip 1 as an example for illustration, and Figure 2 In the middle, quantum chip 1 has a single-layer structure; the first combined control line 31 is essentially a connecting line, like a coaxial line, in Figure 2 The diagram is temporarily represented by the attached figure labeled 31; and Figure 2 In the accompanying diagram, GND indicates a grounding substrate on which the qubits are disposed. Additionally, due to limitations in the focus of the image and space, the grounding of the second terminal of the control matching unit 32 is not specifically illustrated. It should also be noted that the signal generator 2 may specifically include a vector signal generator 2 to generate electrical signals including high-frequency control information, and / or the signal generator 2 may specifically include an arbitrary wave generator to generate electrical signals including low-frequency control information. Furthermore, the aforementioned electrical signals may be processed by a cryogenic microwave circuit before being transmitted to the first combined control line 31, thereby better achieving the driving and frequency control of the qubits.

[0049] Furthermore, when the electrical signal is a voltage signal including high-frequency control information, the rotation of the qubit along the XY axis can be achieved by adjusting the amplitude and phase of the voltage signal while ensuring that its frequency remains equal to the target operating frequency. When the electrical signal is a current signal including low-frequency control information, the magnetic field and the magnetic flux of the superconducting quantum interference device 123 can be changed by altering the magnitude and direction of the current. The change in magnetic flux leads to a change in the energy level structure of the qubit, thereby achieving the rotation of the qubit along the Z axis. Moreover, after manipulating the qubit, the resulting quantum signal is transmitted to an analog-to-digital converter via a low-temperature microwave circuit, enabling the acquisition of quantum signals.

[0050] In summary, this application provides a quantum bit control circuit that, with only one external control channel, achieves the driving and frequency control of the quantum bit in conjunction with the control matching unit 32. At the same time, the reduced control channel facilitates the setting of the measurement and control channel, and is beneficial to the wiring design and packaging of the quantum chip 1, as well as the integrated design.

[0051] Based on the above embodiments:

[0052] In a preferred embodiment, when the quantum chip 1 has a single-layer structure, the qubits and the qubit control circuit are located on the same layer; the cross capacitor 12 includes a first part 121 and a second part 122 that are perpendicular to each other, and the qubit control circuit and the resonant cavity are located at opposite corners of the first part 121 and the second part 122 that are perpendicular to each other.

[0053] In this embodiment, when the quantum chip 1 has a single-layer structure (i.e., only one substrate layer), both the qubits and the qubit control circuitry are located on the same layer. To minimize interference between the qubit control circuitry and the resonant cavity, they can be separated to a certain extent. Specifically, the cross capacitor 12 includes a first part 121 and a second part 122 that are perpendicular to each other. The qubit control circuitry and the resonant cavity are located diagonally opposite each other in the first part 121 and the second part 122. For ease of explanation, taking a quadrant as an example, the first part 121 and the second part 122 of the cross capacitor 12 divide the four quadrants. When the qubit control circuitry is in the first quadrant, the resonant cavity is in the third quadrant, and vice versa, to ensure the diagonal positioning. Please refer to [reference needed]. Figure 2 , Figure 2 The first part of the cross capacitor 12 is shown by reference numeral 121 in the attached drawing. Figure 2 The entire vertical capacitor arm is the first part 121), and the second part of the cross capacitor 12 is shown as 122 in the attached drawing. Figure 2 The entire horizontal capacitor arm is the second part (122). At this time, the quantum bit control circuit is in the first quadrant and the resonant cavity is in the third quadrant. When the quantum bit control circuit is in the second quadrant, the resonant cavity is in the fourth quadrant, and vice versa, to ensure the diagonal position setting. As for the specific position in the quadrant, it can be determined according to the function to be achieved by the resonant cavity and the quantum bit control circuit.

[0054] As a preferred embodiment, the control matching unit 32 comprises a first control line 321 and a second control line 322; a head end of the first control line 321 is separated from the first part 121 of the cross capacitor 12 by a first preset distance and separated from the second part 122 of the cross capacitor 12 by a second preset distance, for coupling the received electrical signal comprising high-frequency control information with the cross capacitor 12, so that the equivalent coupling capacitance value of the quantum bit is equal to the target coupling capacitance value; a head end of the second control line 322 is separated from the first part 121 by a third preset distance and separated from the second part 122 by a fourth preset distance, for coupling the received electrical signal comprising low-frequency control information with the superconducting quantum interference device 123 to form a magnetic field, so that the working frequency of the quantum bit is equal to the target working frequency; wherein the third preset distance is less than the first preset distance, a tail end of the second control line 322 is connected with a tail end of the first control line 321, and a common end of the connection is connected with the first combined control line 31.

[0055] In this embodiment, the first setting form of the control matching unit 32 when the quantum chip 1 is a single-layer structure is given. It should be noted that for the second control line 322, after receiving the electrical signal comprising high-frequency control information, it is also unable to make the equivalent coupling capacitance value of the quantum bit equal to the target coupling capacitance value, and the processing of the electrical signal comprising high-frequency control information can be ignored; similarly, for the first control line 321, after receiving the electrical signal comprising low-frequency control information, it is also unable to make the working frequency of the quantum bit equal to the target working frequency, and the processing of the electrical signal comprising low-frequency control information can be ignored. It can be understood that the setting position of the first control line 321 ensures that it can make the equivalent coupling capacitance value of the quantum bit equal to the target coupling capacitance value, and the specific values of the first preset distance and the second preset distance are not limited, and in actual use, the position that can ensure that the equivalent coupling capacitance value reaches the target coupling capacitance value through continuous experimental testing is the one to be sought; the setting position of the second control line 322 ensures that it can make the working frequency of the quantum bit equal to the target working frequency, and the specific values of the third preset distance and the fourth preset distance are not limited, and in actual use, the position that can ensure that the working frequency of the quantum bit reaches the target working frequency through continuous experimental testing is the one to be sought. In addition, the tail ends of the first control line 321 and the second control line 322 include but are not limited to connecting to the packaging pins of the quantum chip 1, which is beneficial to the arrangement of the test terminals of the quantum chip 1 and saves the test resources of low-temperature measurement and control, and is not particularly limited here, and is determined according to the application actual.

[0056] Please refer to Figure 3 , Figure 3 for another structure diagram of the quantum bit control line provided by the present application. Figure 3The first control line 321 and the second control line 322 are schematically shown in the figure. The cross-capacitor 12 is still connected to Figure 2 The first control line 321 and the second control line 322 are schematically shown in the figure. The cross-capacitor 12 is still connected to Figure 3 The first control line 321 and the second control line 322 are schematically shown in the figure. The cross-capacitor 12 is still connected to Figure 3 The first control line 321 and the second control line 322 are schematically shown in the figure. The cross-capacitor 12 is still connected to Figure 3 The first control line 321 and the second control line 322 are schematically shown in the figure. The cross-capacitor 12 is still connected to Figure 3 The first control line 321 and the second control line 322 are schematically shown in the figure. The cross-capacitor 12 is still connected to Figure 3 The first control line 321 and the second control line 322 are schematically shown in the figure. The cross-capacitor 12 is still connected to Figure 3 The first control line 321 and the second control line 322 are schematically shown in the figure. The cross-capacitor 12 is still connected to Figure 3 The first control line 321 and the second control line 322 are schematically shown in the figure. The cross-capacitor 12 is still connected to Figure 3As an example, the first combination control line 31, the first control line 321, and the second control line 322 are coaxial lines. In order to show the structure as much as possible, the inner core of the coaxial line is filled with gray to distinguish it from the shell.

[0057] It should be further noted that in the actual simulation, it is found that the coupling capacitance value of the XY control line outputting the XY signal and the cross-capacitor after coupling is 0.7214fF, and the mutual inductance value of the Z control line outputting the Z signal and the superconducting quantum interference device after coupling is 2.13pH; and the coupling capacitance value of the obtained electrical signal and the cross-capacitor after coupling is 0.7217fF, and the mutual inductance value of the electrical signal and the superconducting quantum interference device after coupling is 2.04pH, which well meets the requirements of driving and frequency regulation of the quantum bit.

[0058] As a preferred embodiment, the control matching part 32 comprises:

[0059] The second combination control line 323 is connected to the first end of the first combination control line 31; the second end of the second combination control line 323 is separated from the first part 121 of the cross-capacitor 12 by a fifth preset distance and separated from the second part 122 of the cross-capacitor 12 by a sixth preset distance; wherein the fifth preset distance and the sixth preset distance are preset distances that satisfy the capacitance regulation condition, and the capacitance regulation condition is that when receiving an electrical signal including high-frequency control information, the equivalent coupling capacitance value of the quantum bit is equal to the target coupling capacitance value.

[0060] The ground branch 324 is connected to the second end of the second combination control line 323, and the second end of the ground branch 324 is grounded, for regulating the coupling mutual inductance value between the received electrical signal including low-frequency control information and the superconducting quantum interference device 123, so that the working frequency of the quantum bit is equal to the target working frequency.

[0061] In this embodiment, a second configuration of the control matching unit 32 is presented when the quantum chip 1 has a single-layer structure. It should be noted that the second combined control line 323 is essentially the same as the first combined control line 31, and can be a coaxial line. It is understood that the placement of the second combined line ensures that the equivalent coupling capacitance value of the qubit equals the target coupling capacitance value. The specific values ​​of the fifth and sixth preset distances are not limited; the desired position is determined through continuous experimental testing to meet the capacitance control conditions. As for the grounding stub 324, its purpose is mainly to regulate the coupling inductance value between the received electrical signal, including low-frequency control information, and the superconducting quantum interference device 123, i.e., to regulate the size of the coupling area, thereby ensuring that the operating frequency of the qubit equals the target operating frequency. It should be noted that, through actual testing, it has been found that after the position of the second combined control line 323 is determined, the design of the grounding stub 324 only changes the size of the coupling area, and the change in the equivalent coupling capacitance value is negligible. As a preferred configuration, the position of the second combined control line 323 can be determined first by relying on the capacitance control condition. Then, the structure of the grounding branch 324 is adjusted to adjust the coupling area. At this time, the equivalent coupling capacitance value is considered to remain unchanged. Finally, the coupling mutual inductance value is changed so that the operating frequency of the quantum bit is equal to the target operating frequency.

[0062] Please refer to Figure 4 , Figure 4 This is a schematic diagram of another quantum bit control circuit provided by the present invention. The cross capacitor 12 is still connected to... Figure 2 The same includes a first part 121 and a second part 122. The second end of the second combined control line 323 is indicated by the reference numeral D. The distance between the D end and the first part 121 of the cross capacitor 12 is the fifth preset distance (e.g., taking the central axis W1 of the first part 121 as a reference, the fifth preset distance between the D end and the first part 121 is the distance between the D end and the central axis W1 of the first part 121). The distance between the D end and the second part 122 of the cross capacitor 12 is the sixth preset distance (e.g., taking the central axis W2 of the second part 122 as a reference, the sixth preset distance between the D end and the second part 122 is the distance between the D end and the central axis W2 of the second part 122). In actual measurement, it was found that the fifth preset distance is less than the first preset distance mentioned above and greater than the third preset distance mentioned above. In addition, Figure 4 The first combination control line 31 and the second combination control line 323 are both coaxial lines, which are used as examples for illustration. In order to show the structure as much as possible, the inner core of the coaxial line is filled with gray as a distinguishing mark from its outer shell.

[0063] It can be seen that, by the above manner, the layout area occupied by the control lines can be further reduced, that is, the original XY control lines and Z control lines occupy two layout areas, and now only the connected first and second combined control lines 31 and 323 occupy one layout area, the reduction of the layout area is more conducive to the wiring design and packaging inside the quantum chip 1, facilitates the arrangement of the measurement and control channel, greatly relieves the design and measurement and control resource occupation pressure, and improves the measurement and control efficiency; and this manner greatly reduces the crosstalk and coupling caused by crowded layout space, ensures good signal integrity, and increases the convenience of wiring layout.

[0064] As a preferred embodiment, the ground branch 324 is a first bent branch with at least one right angle.

[0065] In this embodiment, a design manner of the ground branch 324 is given, which can be a first bent branch with at least one right angle, please continue to refer to Figure 4 , Figure 4 The ground branch 324 in the above embodiment is a first bent branch with one right angle, which includes a connected horizontal segment and a vertical segment, and of course can be a branch design with more right angles, which is not particularly limited here, and is subject to the function implementation; it should be noted that Figure 4 There are two first bent branches in the above embodiment because in a coaxial line, the outer shell wraps the inner core, and there are two left and right exit points between the inner core and the outer shell in the diameter.

[0066] It should be further noted that in the actual simulation, it is found that the coupling capacitance value of the XY control line outputting an XY signal and coupled with a cross capacitor in the prior art is 0.7214fF, and the mutual inductance value of the Z control line outputting a Z signal and coupled with a superconducting quantum interference device in the prior art is 2.13pH; and the coupling capacitance value of the finally obtained electrical signal and the cross capacitor after coupling is 0.7341fF, and the mutual inductance value of the electrical signal and the superconducting quantum interference device after coupling is 1.98pH, which still well meets the requirements of driving and frequency regulation of the quantum bit.

[0067] As a preferred embodiment, when the quantum chip 1 is a double-layer structure, the first combined control line 31 and the control matching part 32 are located on the first layer of the quantum chip 1; and the cross capacitor 12 and the resonant cavity are located on the second layer of the quantum chip 1.

[0068] In this embodiment, it is further given that the quantum chip 1 can be a double-layer structure chip, and the double-layer design can be realized by using a flip-chip process, and then the first integrated control line 31 and the control matching part 32 are arranged on the first layer of the quantum chip 1, and the cross-capacitor 12 and the resonant cavity are arranged on the second layer of the quantum chip 1, so as to avoid the crosstalk and coupling between signals as much as possible, and facilitate the actual application; and in this case, the control matching part 32 can be arranged at a position closer to the cross-capacitor 12, which will be described in the following embodiments, and will not be repeated here. In addition, when the first layer is the top layer and the second layer is the bottom layer, or when the first layer is the bottom layer and the second layer is the top layer, preferably, the first integrated control line 31 and the control matching part 32 can be arranged on the top layer. Please refer to Figure 5 , Figure 5 The structure diagram of another quantum bit control line provided by the present application is shown, wherein the GND_BOT mark represents the bottom layer, the GND_TOP mark represents the top layer, and the representation of the first integrated control line 31 and the signal wave generator is temporarily ignored due to the further display focus of the picture, and the position of the resonant cavity is embodied in the form of the resonant cavity and the coupling part of the cross-capacitor 12, and it is presented by the reference numeral 4 in Figure 5 . It should be noted that Figure 5 the control matching part 32 is located on the top layer, and the cross-capacitor 12 and the resonant cavity are located on the bottom layer.

[0069] As a preferred embodiment, the first layer and the second layer are separated by a preset layer spacing; the control matching part 32 comprises:

[0070] The third integrated control line 325 is connected with the first end of the first integrated control line 31, the projection of the third integrated control line 325 on the second layer is separated from the first part 121 of the cross-capacitor 12 by a seventh preset distance, and the target end is separated from the second part 122 of the cross-capacitor 12 by an eighth preset distance; wherein the seventh preset distance and the eighth preset distance are preset distances that satisfy the capacitance control condition in the presence of the preset layer spacing, and the capacitance control condition is that the equivalent coupling capacitance value of the quantum bit is equal to the target coupling capacitance value when receiving the electrical signal comprising the high-frequency control information;

[0071] The coupling area amplification component 326 is connected with the second end of the third integrated control line 325, and the second end of the coupling area amplification component 326 is grounded, and is used to control the mutual inductance value between the received electrical signal comprising the low-frequency control information and the superconducting quantum interference device 123, so that the working frequency of the quantum bit is equal to the target working frequency.

[0072] In this embodiment, the configuration of the control matching unit 32 is given when the qubit has a two-layer structure. In this case, the qubit control circuit is not on the same plane as the qubit, and the preset layer spacing between the first layer and the second layer is a fixed layer spacing. The specific value of the spacing is not particularly limited here. Given the presence of the preset interlayer spacing, the position of the third combined control line 325 is determined. This third combined control line 325 is essentially the same as the first combined control line 31, and can be a coaxial line. Due to the non-planar arrangement, the target end of the projection of the third combined control line 325 onto the second layer (which can be understood as the projection of the second end of the third combined control line 325 onto the second layer) is a seventh preset distance away from the first part 121 of the cross capacitor 12, and an eighth preset distance away from the second part 122 of the cross capacitor 12. The position of the third combined control line 325 ensures that the equivalent coupling capacitance value of the quantum bit is equal to the target coupling capacitance value. The specific values ​​of the seventh and eighth preset distances are not limited; in practice, through continuous experimental testing, the position that satisfies the capacitance control conditions while maintaining the preset interlayer spacing is the desired position. As for the coupling area amplification component 326, its main purpose is to regulate the coupling mutual inductance value between the received electrical signal, including low-frequency control information, and the superconducting quantum interference device 123, i.e., to regulate the size of the coupling area, thereby ensuring that the operating frequency of the quantum bit is equal to the target operating frequency. It should be noted that, through actual testing, it was found that after the position of the third combined control line 325 is determined, the structural design adjustment of the coupling area method component only changes the size of the coupling area to change the coupling mutual inductance value. The change in the equivalent coupling capacitance value is negligible and can be ignored. As a preferred setting, the position of the third combined control line 325 can be determined first by relying on the capacitance adjustment condition. Then, the structure of the coupling area amplification component 326 is adjusted to achieve the adjustment of the coupling area. At this time, the equivalent coupling capacitance value is considered to remain unchanged. Finally, the coupling mutual inductance value is changed so that the operating frequency of the quantum bit is equal to the target operating frequency. It can be understood that, in order to achieve impedance matching, the third combined control line 325 can be connected to a thicker impedance matching line in practical applications, and then the impedance matching line is connected to the first combined control line 31. No special limitation is made here.

[0073] Please refer to Figure 6 , Figure 6 This is a schematic diagram of another quantum bit control circuit provided by the present invention. The cross capacitor 12 is still connected to... Figure 2 The same includes Part 1, Chapter 121 and Part 2, Chapter 122. Figure 6 and Figure 5 Correspondingly, and for ease of explanation, what is shown here is... Figure 5The control matching part 32 located in the top layer is projected on the bottom layer (here, for the convenience of illustration, the projection of the third combined control line on the bottom layer is still denoted by reference numeral 325, and the projection of the coupling area amplification assembly on the bottom layer is still denoted by reference numeral 326); in addition, under the condition that the first combined control line 31 is integrally connected with the third combined control line 325, the drawing of the first combined control line 31 is temporarily ignored for the purpose of focusing on the picture display; in Figure 6 In the embodiment, the target end of the third combined control line 325 is denoted by reference numeral F, and the distance between the end F and the first part 121 of the cross capacitor 12 is the seventh preset distance (for example, taking the center axis W1 of the first part 121 as the reference, the seventh preset distance between the end F and the first part 121 is the distance between the end F and the center axis W1 of the first part 121), and the distance between the end F and the second part 122 of the cross capacitor 12 is the eighth preset distance (for example, taking the center axis W2 of the second part 122 as the reference, the eighth preset distance between the end F and the second part 122 is the distance between the end F and the center axis W2 of the second part 122), and it is found in the actual measurement that the seventh preset distance is smaller than the fifth preset distance described above. In addition, the third combined control line 325 can still be a coaxial line in nature, Figure 6 In the embodiment, for the purpose of clear display, the third combined control line 325 is temporarily shown in the form of a common line for brief illustration.

[0074] It can be seen that, by the above-mentioned manner, the area of the control line can be further reduced, that is, the original XY control line and Z control line occupy two areas, and now only the first combined control line 31 and the third combined control line 325 occupy one area, the reduction of the area is more conducive to the wiring design and packaging inside the quantum chip 1, facilitates the arrangement of the measurement and control channel, greatly relieves the pressure of resource occupation in design and measurement and control, and improves the measurement and control efficiency; and this manner greatly reduces the crosstalk and coupling caused by the crowded area, avoids the crosstalk and coupling between the control lines of different quantum bits, ensures the good signal integrity, and increases the convenience of wiring layout.

[0075] As a preferred embodiment, the coupling area amplification assembly 326 is a fourth combined control line in the form of a spiral.

[0076] In the embodiment, the first setting form of the coupling area amplification assembly 326 is given, that is, the fourth combined control line in the form of a spiral, which can still be a coaxial line in nature, one end of the fourth combined control line is connected with the second end of the third combined control line 325, and the other end of the fourth combined control line is grounded, Figure 5 and Figure 6The above-described coupling area amplification component 326 is shown in the illustration. Of course, in practical applications, other structural forms of coupling area amplification component 326 can also be used to increase the coupling area to control the coupling mutual inductance value.

[0077] It should also be noted that, in the actual simulation, it was found that when the XY control line outputs an XY signal in the prior art, the coupling capacitance value after coupling with the cross capacitor is 0.7214 fF, and when the Z control line outputs a Z signal in the prior art, the mutual inductance value after coupling with the superconducting quantum interference device is 2.13 pH. However, by applying the setting method of the control matching unit in this embodiment, the final coupling capacitance value after coupling with the cross capacitor is 0.7285 fF, and the mutual inductance value after coupling with the superconducting quantum interference device is 2.35 pH, which well meets the requirements for driving and frequency control of the quantum bit.

[0078] As a preferred embodiment, the coupling area amplification component 326 is a second bent branch with at least one right angle.

[0079] In this embodiment, a second configuration of the coupling area amplification component 326 is provided, namely, a form with a second bent branch having at least one right angle. Please refer to... Figure 7 , Figure 7 This is a schematic diagram of another quantum bit control circuit provided by the present invention. The cross capacitor 12 is still connected to... Figure 2 The same includes the first part 121 and the second part 122. For ease of explanation, what is shown here is the projection of the entire control matching part 32 located on the top layer onto the bottom layer (for ease of explanation, the projection of the third combined control line on the bottom layer is still indicated by the reference numeral 325, and similarly, the projection of the coupling area enlargement component on the bottom layer is still indicated by the reference numeral 326). In addition, due to the limited focus of the image display, since it is known that the first combined control line 31 and the third combined control line 325 are connected as a whole, the drawing of the first combined control line 31 is temporarily ignored. Figure 7 The projection of the third composite control line 325 on the second layer is in the fourth quadrant, and the resonant cavity is in the second quadrant of the second layer; Figure 7 The target end of the third combined control line 325 is indicated by the reference numeral G. The distance between the G end and the first part 121 of the cross capacitor 12 is the seventh preset distance (e.g., taking the central axis W1 of the first part 121 as a reference, the seventh preset distance between the G end and the first part 121 is the distance between the G end and the central axis W1 of the first part 121). The distance between the G end and the second part 122 of the cross capacitor 12 is the eighth preset distance (e.g., taking the central axis W2 of the second part 122 as a reference, the eighth preset distance between the G end and the second part 122 is the distance between the G end and the central axis W2 of the second part 122). Furthermore, Figure 7Take the third integrated control line 325 as the coaxial line for example, in order to show the structure as much as possible, the inner core of the coaxial line is filled with gray as the distinguishing mark from the shell.

[0080] In this embodiment, the coupling area amplification component 326 can be a second bending branch with at least one right angle, referring to Figure 7 As shown in the figure, because in the coaxial line, the shell wraps the inner core, there are two left and right lead-out points between the inner core and the shell in the diameter, Figure 7 Take one lead-out point as the starting point, set a second bending branch with three right angles, the whole structure is similar to the form of a paper clip, to realize the regulation and control of the coupling mutual inductance value, so that the working frequency of the quantum bit is equal to the target working frequency.

[0081] It also needs to be explained that in the actual simulation, it is found that the coupling capacitance value of the XY control line output XY signal and the cross-capacitance coupling in the prior art is 0.7214fF, and the mutual inductance value of the Z control line output Z signal and the superconducting quantum interference device coupling in the prior art is 2.13pH; and the coupling capacitance value of the electric signal obtained by applying the setting mode of the control matching part of the embodiment and the cross-capacitance coupling is 0.7069fF, and the mutual inductance value of the electric signal and the superconducting quantum interference device coupling mutual inductance is 2.19pH, which well completes the requirements of driving and frequency regulation of the quantum bit.

[0082] As a further description of the above embodiment, an equivalent circuit diagram of the whole quantum bit under the action of the electric signal output by the quantum bit regulation line is given, please refer to Figure 8 , Figure 8 An equivalent circuit diagram of the whole quantum bit under the action of the electric signal output by the quantum bit regulation line provided by the present application, wherein C1 is the equivalent capacitance of the cross-capacitance, C2 is the equivalent capacitance after the electric signal including high-frequency control information and the cross-capacitance coupling, L1 is the equivalent inductance in the coupling mutual inductance, and the superconducting quantum interference device is Figure 8 In the figure, the superconducting quantum interference device is simply indicated by the reference sign SQUID, which is essentially composed of a Josephson structure, Figure 8 In the figure, the Josephson junction is represented by a square box with a cross inside, and a circle is marked.

[0083] The present application also provides a quantum chip, which comprises a quantum bit and a quantum bit regulation line as described above; wherein the quantum bit comprises a cross-capacitance and a resonant cavity, and the cross-capacitance comprises a superconducting quantum interference device.

[0084] For the quantum chip provided in the present application, please refer to the above-mentioned embodiments of the quantum bit regulation line, which will not be described here.

[0085] The application further provides a quantum computer comprising the quantum chip as described above.

[0086] For the quantum computer provided in the application, refer to the above-mentioned embodiments of the quantum bit regulating circuit, which will not be repeated here.

[0087] The various embodiments are described in the specification by way of progression, each building on the last to facilitate ease of understanding. The embodiments are illustrative of the application but not limiting thereof. Relative terms are used to describe one element's relationship to another element as the physical disposition or orientation of various components may change with the passage of time. Such relative terms include, but are not limited to, relative spatial and / or directional terms, such as left, right, front, back, upper, lower, above, below, beneath, rearward, downward, upward, etc. Exemplary terms include but are not limited to, "element" and / or "component" and / or the like. Such terms are used in connection with a variety of embodiments, and are not meant to limit the position, orientation, and / or other attributes of the elements, components, and / or the like. In addition, the terms "first", "second", and / or other similar

[0088] The above description of disclosed embodiments provides enabling disclosure sufficient for others to practice the application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A quantum bit tuning circuit, characterized by, The application is applied to a quantum chip, the quantum chip comprises a quantum bit, the quantum bit comprises a cross capacitor and a resonant cavity, the cross capacitor comprises a superconducting quantum interference device, and the quantum bit regulation circuit comprises: A first body control line is connected with an output end of a signal generator arranged outside the quantum chip and a first end of a control matching part arranged inside the quantum chip, and is used for outputting an electric signal output by the signal generator to the control matching part, wherein the electric signal comprises low-frequency control information and high-frequency control information; The control matching part is grounded at a second end, is used for coupling the received electric signal comprising the high-frequency control information with the cross capacitor, so that an equivalent coupling capacitance value of the quantum bit is equal to a target coupling capacitance value, and is used for coupling the received electric signal comprising the low-frequency control information with the superconducting quantum interference device to form a magnetic field, so that an operating frequency of the quantum bit is equal to a target operating frequency; The control matching part comprises: A second body control line is connected with the first body control line at a first end, a second end of the second body control line is separated from a first part of the cross capacitor by a fifth preset distance and is separated from a second part of the cross capacitor by a sixth preset distance, wherein the fifth preset distance and the sixth preset distance are preset distances satisfying a capacitance regulation condition, and the capacitance regulation condition is that the equivalent coupling capacitance value of the quantum bit is equal to the target coupling capacitance value when the electric signal comprising the high-frequency control information is received; A grounding branch is connected with the second end of the second body control line at a first end, a second end of the grounding branch is grounded, and is used for regulating a coupling mutual inductance value between the received electric signal comprising the low-frequency control information and the superconducting quantum interference device, so that the operating frequency of the quantum bit is equal to the target operating frequency.

2. The quantum bit gate circuit of claim 1, wherein, When the quantum chip is a single-layer structure; The quantum bit and the quantum bit regulation circuit are located in the same layer; The cross capacitor comprises the first part and the second part perpendicular to each other, and the quantum bit regulation circuit and the resonant cavity are arranged at diagonal positions of the first part and the second part perpendicular to each other.

3. The quantum bit gate circuit of claim 2, wherein, The control matching part comprises a first control line and a second control line; A first end of the first control line is separated from the first part of the cross capacitor by a first preset distance and is separated from the second part of the cross capacitor by a second preset distance, and is used for coupling the received electric signal comprising the high-frequency control information with the cross capacitor, so that the equivalent coupling capacitance value of the quantum bit is equal to the target coupling capacitance value; A first end of the second control line is separated from the first part by a third preset distance and is separated from the second part by a fourth preset distance, and is used for coupling the received electric signal comprising the low-frequency control information with the superconducting quantum interference device to form a magnetic field, so that the operating frequency of the quantum bit is equal to the target operating frequency; The third preset distance is less than the first preset distance, a second end of the second control line is connected with a second end of the first control line, and a common end connected with the first body control line.

4. The quantum bit gate circuit of claim 1, wherein, The ground branch is a first bent branch with at least one right angle.

5. The quantum bit gate circuit of any one of claims 1 to 4, wherein, When the quantum chip is a double-layer structure; The first body control line and the control matching part are located on a first layer of the quantum chip. The cross-capacitor and the resonant cavity are located on a second layer of the quantum chip.

6. The quantum bit gate circuit of claim 5, wherein, The first layer and the second layer are separated by a preset layer spacing; the control matching part comprises: A third body control line, a first end of which is connected to the first body control line, a target end of a projection of the third body control line on the second layer is separated from a first part of the cross-capacitor by a seventh preset distance, and the target end is separated from a second part of the cross-capacitor by an eighth preset distance; wherein the seventh preset distance and the eighth preset distance are preset distances that satisfy a capacitance control condition in the presence of the preset layer spacing, and the capacitance control condition is that when an electrical signal including the high-frequency control information is received, the equivalent coupling capacitance value of the quantum bit is equal to the target coupling capacitance value; A coupling area amplification component, a first end of which is connected to a second end of the third body control line, and a second end of the coupling area amplification component is grounded, for regulating the mutual inductance value between the received electrical signal including the low-frequency control information and the superconducting quantum interference device, so that the operating frequency of the quantum bit is equal to the target operating frequency.

7. The quantum bit gate circuit of claim 6, wherein, The coupling area amplification component is a fourth body control line in a spiral shape.

8. The quantum bit gate circuit of claim 6, wherein, The coupling area amplification component is a second bent branch with at least one right angle.

9. A quantum chip, characterized by The quantum bit further comprises a quantum bit control circuit as claimed in any one of claims 1 to 8; wherein the quantum bit comprises a cross-capacitor and a resonant cavity, and the cross-capacitor comprises a superconducting quantum interference device.

10. A quantum computer, characterized by, The quantum chip as claimed in claim 9.

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