Quantum circuit, amplification device, chip structure, measurement method and apparatus for state of qubit, electronic device, computer-readable storage medium, and computer program product

Abstract

A quantum circuit, an amplification device, a chip structure, a measurement method and apparatus for a state of a qubit, an electronic device, a computer-readable storage medium, and a computer program product. The quantum circuit comprises: one end of a capacitor module is connected to a coupling end, and the other end of the capacitor module is connected to a grounding end; one end of a first linear inductor module is connected to the coupling end, the other end of the first linear inductor module is connected to one end of a second linear inductor module, and the other end of the second linear inductor module is connected to the grounding end; a Josephson junction is connected in parallel to two ends of the second linear inductor module; a qubit, a measurement input end, and a measurement output end are connected to the coupling end, the measurement input end is configured to input a microwave signal for measuring the qubit, and the measurement output end is configured to output a target voltage signal, the target voltage signal being used for indicating a state of the qubit.

Description

A quantum circuit, amplifier device, chip structure, and quantum bit state measurement method, device, electronic device, computer-readable storage medium, and computer program product

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on the Chinese patent application with application number 202311818178.2 and application date of December 26, 2023, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby introduced into this application as a reference. Technical Field

[0003] The present application relates to the field of quantum computing technology, and in particular to a quantum circuit, an amplifier device, a chip structure, and a method, device, electronic device, computer-readable storage medium, and computer program product for measuring the state of a quantum bit. Background Art

[0004] Quantum computing is a research area focused on developing computing power. During quantum computing tasks, the state of qubits (qubits) changes, necessitating measurement. Related technologies typically amplify the qubit signal when measuring the state of qubits. However, energy leakage often occurs when qubits couple with the outside world, reducing the accuracy of qubit state measurements.

[0005] Summary of the Invention

[0006] The following is an overview of the subject matter described in detail in this application. This overview is not intended to limit the scope of protection of the claims.

[0007] The embodiments of the present application provide a quantum circuit, an amplifier device, a chip structure, and a method, apparatus, electronic device, computer-readable storage medium, and computer program product for measuring the state of a quantum bit, which can reduce quantum bit energy leakage, improve the accuracy of quantum bit state measurement, and reduce the circuit complexity of quantum bit state measurement.

[0008] An embodiment of the present application provides a quantum circuit, including a quantum bit, an amplifier circuit, a ground terminal, a coupling terminal, a measurement input terminal, and a measurement output terminal, wherein the amplifier circuit includes a capacitor module, a first linear inductor module, a second linear inductor module, and a Josephson junction;

[0009] One end of the capacitor module is connected to the coupling end, and the other end of the capacitor module is connected to the ground end;

[0010] One end of the first linear inductor module is connected to the coupling end, the other end of the first linear inductor module is connected to one end of the second linear inductor module, and the other end of the second linear inductor module is connected to the ground end;

[0011] The Josephson junction is connected in parallel to both ends of the second linear inductor module;

[0012] The quantum bit, the measurement input end, and the measurement output end are connected to the coupling end. The measurement input end is used to input a microwave signal for measuring the quantum bit. The measurement output end is used to output a target voltage signal. The target voltage signal is used to indicate the state of the quantum bit.

[0013] The embodiment of the present application further provides an amplifier device, comprising an amplifier circuit, a ground terminal, and a coupling terminal, wherein the amplifier circuit comprises a capacitor module, a first linear inductor module, a second linear inductor module, and a Josephson junction;

[0014] One end of the capacitor module is connected to the coupling end, and the other end of the capacitor module is connected to the ground end;

[0015] One end of the first linear inductor module is connected to the coupling end, the other end of the first linear inductor module is connected to one end of the second linear inductor module, and the other end of the second linear inductor module is connected to the ground end;

[0016] The Josephson junction is connected in parallel to both ends of the second linear inductor module.

[0017] The embodiments of the present application also provide a chip structure, including the quantum circuit provided by the embodiments of the present application, or including the amplification device provided by the embodiments of the present application.

[0018] The present application also provides a method for measuring a quantum bit state, which is applied to a processor connected to the measurement output terminal of the quantum circuit provided in the present application. The method includes:

[0019] When a microwave signal is input to the measurement input end, a target voltage signal output by the measurement output end is obtained;

[0020] determining a target phase and a target amplitude according to the target voltage signal, and determining a target measurement point in a first coordinate space according to the target phase and the target amplitude;

[0021] The state of the quantum bit is determined based on an affiliation between the target measurement point and the first sample point area or the second sample point area, where the first sample point area and the second sample point area are preset in the first coordinate space, and the first sample point area and the second sample point area are respectively used to indicate two different states of the quantum bit.

[0022] The embodiment of the present application further provides a device for measuring the state of a quantum bit, the device being connected to the measurement output terminal of the aforementioned quantum circuit, and comprising:

[0023] a signal acquisition module, configured to acquire a target voltage signal output by the measurement output terminal when a microwave signal is input to the measurement input terminal;

[0024] a signal processing module configured to determine a target phase and a target amplitude according to the target voltage signal, and determine a target measurement point in a first coordinate space according to the target phase and the target amplitude;

[0025] and a state determination module configured to determine the state of the qubit based on an affiliation between the target measurement point and a first sample point region or a second sample point region, wherein the first sample point region and the second sample point region are preset in the first coordinate space, and the first sample point region and the second sample point region are respectively used to indicate two different states of the qubit.

[0026] An embodiment of the present application also provides an electronic device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, it implements the method for measuring the quantum bit state provided in the embodiment of the present application.

[0027] An embodiment of the present application also provides a computer-readable storage medium, which stores a computer program. The computer program is executed by a processor to implement the method for measuring the quantum bit state provided in the embodiment of the present application.

[0028] The present application also provides a computer program product, comprising a computer program stored in a computer-readable storage medium. A processor of an electronic device reads the computer program from the computer-readable storage medium and executes the computer program, causing the electronic device to implement the quantum bit state measurement method provided in the present application.

[0029] The embodiments of the present application include at least the following beneficial effects: in the amplifying circuit of the quantum circuit, a resonant circuit is formed by setting a capacitor module, a second linear inductor module and a Josephson junction, thereby achieving an amplification effect on the signal of the quantum bit; on this basis, by setting a first linear inductor module, the nonlinearity of the amplifying circuit is reduced, and while meeting the amplification requirements, the coupling between the amplifying circuit and the outside world is reduced, thereby reducing the energy leakage of the quantum bit and improving the accuracy of the quantum bit state measurement; and, the amplifying circuit can be directly coupled with the quantum bit, reducing the setting of other intermediate devices, thereby reducing the circuit complexity of the quantum bit measurement.

[0030] In addition, when measuring the state of a quantum bit, the target phase and target amplitude are determined according to the target voltage signal, the target measurement point is determined in the corresponding first coordinate space according to the target phase and target amplitude, and finally, the state of the quantum bit is determined according to the affiliation between the target measurement point and the first sample point area or the second sample point area. The state of the quantum bit can be quickly determined in a coordinate matching manner based on the pre-obtained first sample point area and second sample point area, thereby improving the measurement efficiency of the quantum bit state.

[0031] Other features and advantages of the present application will be set forth in the following description, and in part will be apparent from the description, or may be understood by practicing the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings are used to provide a further understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.

[0033] FIG1 is a schematic diagram of an optional structure of a quantum circuit provided in an embodiment of the present application;

[0034] FIG2 is an optional potential energy schematic diagram of an amplifier circuit provided in an embodiment of the present application;

[0035] FIG3 is a first optional circuit schematic diagram of a quantum circuit provided in an embodiment of the present application;

[0036] FIG4 is a second optional circuit schematic diagram of a quantum circuit provided in an embodiment of the present application;

[0037] FIG5 is a third optional circuit schematic diagram of a quantum circuit provided in an embodiment of the present application;

[0038] FIG6 is a schematic diagram of an optional structure of an amplifying device provided in an embodiment of the present application;

[0039] FIG7 is a first optional circuit diagram of an amplifier device provided in an embodiment of the present application;

[0040] FIG8 is a second optional circuit diagram of the amplifier device provided in an embodiment of the present application;

[0041] FIG9 is a third optional circuit schematic diagram of the amplifier device provided in an embodiment of the present application;

[0042] FIG10 is a schematic diagram of an optional flow chart of a method for measuring a quantum bit state according to an embodiment of the present application;

[0043] FIG11 is a schematic diagram of an optional coordinate space of a first sample point region and a second sample point region provided in an embodiment of the present application;

[0044] FIG12 is a schematic diagram of an optional change curve of device frequency and magnetic flux provided in an embodiment of the present application;

[0045] FIG13 is a schematic diagram of an optional coordinate space of a target frequency provided in an embodiment of the present application;

[0046] FIG14 is a schematic diagram of an optional architecture of a method for measuring a quantum bit state provided in an embodiment of the present application;

[0047] FIG15 is a schematic diagram of an optional structure of a device for measuring a quantum bit state according to an embodiment of the present application;

[0048] FIG16 is a partial structural block diagram of a terminal provided in an embodiment of the present application;

[0049] FIG17 is a partial structural block diagram of the server provided in an embodiment of the present application. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solutions and advantages of this application more clearly understood, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0051] It should be noted that in each specific embodiment of the present application, when it comes to the need to perform relevant processing based on data related to the structure, attribute information or attribute information set of the quantum circuit, the permission or consent of the information subject will be obtained first. Moreover, the collection, use and processing of these data will comply with relevant laws, regulations and standards, and comply with the principles of legality, legitimacy and necessity, and will not involve obtaining data types prohibited or restricted by laws and regulations. Among them, the target object can be a user or a platform. In addition, when the embodiment of the present application needs to obtain data related to the structure, attribute information or attribute information set of the quantum circuit, the separate permission or consent of the information subject will be obtained through a pop-up window or by jumping to a confirmation page. After clearly obtaining the separate permission or consent of the information subject, the necessary relevant data for enabling the normal operation of the embodiment of the present application will be obtained.

[0052] To facilitate understanding of the technical solutions provided in the embodiments of the present application, some key terms used in the embodiments of the present application are explained here:

[0053] Quantum computing is a computing method designed using the principles of quantum mechanics. The key difference between quantum computing and traditional computing is that it uses quantum bits (qubits) rather than traditional binary bits. Qubits have different properties from traditional binary bits, the most important of which is that they can exist in multiple states simultaneously. Because qubits can represent multiple states simultaneously, they can carry more information than binary bits. Using the same number of qubits, more data operations can be performed than with traditional computing. Therefore, quantum computers can significantly increase computer processing speed.

[0054] Quantum: The quantum in "quantum computing" refers to the smallest discrete unit of computational output.

[0055] A qubit is the fundamental unit of information in quantum computing. Its role in quantum computing is similar to that of a binary bit in traditional computing. While a binary bit is binary and can only store a value of 0 or 1, a qubit can store a superposition of all possible states—a state of |0> and a state of |1>. This can significantly increase computer processing speed.

[0056] Quantum bit unit: The storage unit in the chip used to hold the quantum bits involved in the calculation.

[0057] Superposition: A qubit can represent two states simultaneously. Therefore, a qubit exists in two states simultaneously, a superposition of the two states. When in superposition, the qubit is a combination of all possible states.

[0058] Collapse: A quantum bit is a superposition of all possible states. When a quantum bit is measured, it becomes fixed in one state. This fixation is called collapse.

[0059] Entanglement: Entanglement is the ability of quantum bits to correlate their measurement results. When quantum bits are entangled, they form a system and influence each other. Based on entanglement, the measurement of one quantum bit can be used to infer information about other quantum bits. Furthermore, by adding and entangling more quantum bits in the system, the complexity of problems that can be solved by quantum computers can be increased. For example, for the entanglement of quantum bit unit A, quantum bit unit B, and the entanglement between quantum bit unit A and quantum bit unit B, the states of the quantum bits in quantum bit unit A and quantum bit unit B can be used to represent some operations, while the entanglement between quantum bit unit A and quantum bit unit B can be used to represent other operations, thereby improving the computing power of the computer.

[0060] Photon: A fundamental particle that transmits electromagnetic interactions. For example, a quantum bit in the |1> state will change to the |0> state if it releases a photon.

[0061] Quantum computing is a research direction for developing computing power. During the processing of quantum computing tasks, the state of qubits changes, necessitating measurement of the qubit state. Related technologies for measuring qubit states typically require amplifying the qubit signal. However, energy leakage often occurs when qubits couple with the outside world, reducing the accuracy of qubit state measurements.

[0062] Based on this, the embodiments of the present application provide a quantum circuit amplifier device, chip structure, and quantum bit state measurement method, device, electronic device, computer-readable storage medium, and computer program product, which can reduce quantum bit energy leakage, improve the accuracy of quantum bit state measurement, and reduce the circuit complexity of quantum bit state measurement.

[0063] 1 , which is a schematic diagram of an optional structure of a quantum circuit provided in an embodiment of the present application, wherein the quantum circuit includes a quantum bit 110, an amplifier circuit 120, a ground terminal 130, a coupling terminal 140, a measurement input terminal 150, and a measurement output terminal 160. The amplifier circuit 120 includes a capacitor module 121, a first linear inductor module 122, a second linear inductor module 123, and a Josephson junction. Junction) 124; one end of the capacitor module 121 is connected to the coupling end 140, and the other end of the capacitor module 121 is connected to the ground end 130; one end of the first linear inductor module 122 is connected to the coupling end 140, the other end of the first linear inductor module 122 is connected to one end of the second linear inductor module 123, and the other end of the second linear inductor module 123 is connected to the ground end 130; the Josephson junction 124 is connected in parallel to both ends of the second linear inductor module 123; the quantum bit 110, the measurement input end 150 and the measurement output end 160 are respectively coupled to the corresponding coupling end 140; wherein the measurement input end 150 is used to input a microwave signal for measuring the quantum bit 110, and the measurement output end 160 is used to output a target voltage signal, and the target voltage signal is used to indicate the state of the quantum bit 110; the measurement input end 150 can be connected to a device for generating a microwave signal, and the measurement output end 160 can be connected to a device for receiving a voltage signal.

[0064] It should be noted that qubit 110 possesses the properties of superposition and entanglement, enabling quantum computers to perform calculations faster than traditional computers. A Josephson junction 124, also known as a superconducting tunnel junction, is typically constructed by sandwiching at least two superconductors with a very thin barrier layer (less than a specified thickness). The thickness of the barrier layer is less than the coherence length of a Cooper pair, and the barrier layer includes, but is not limited to, an insulating layer or a semiconductor layer. In Josephson junction 124, superconducting electrons can tunnel from one superconductor through the barrier layer to the other superconductor via the tunneling effect. For example, Josephson junction 124 can be a superconductor (S)-semiconductor or insulator (I)-S structure (abbreviated as SIS). In addition to being a structure consisting of at least two superconductors sandwiched by a very thin barrier layer, Josephson junction 124 can also be formed by processing a portion of the superconducting material into a thinner layer than the rest of the superconducting material.

[0065] Based on this, the coupling end 140 refers to a port in a circuit where multiple electrical components are interconnected or influence each other, and the Josephson junction 124 can be used as a nonlinear inductance module; since the Josephson junction 124 and the second linear inductance module 123 are connected in parallel, and the coupling end 140, the first linear inductance module 122, the second linear inductance module 123 and the grounding end 130 are connected in series in sequence, and the coupling end 140, the capacitor module 121 and the grounding end 130 are connected in series in sequence, under the action of the coupling end 140, the capacitor module 121, the second linear inductance module 123 and the Josephson junction 124 form a resonant circuit. The quantum circuit provided with the resonant circuit can amplify the signal of the quantum bit 110, thereby realizing effective measurement of the state of the quantum bit 110.

[0066] Exemplarily, the process of measuring the state of the quantum bit 110 may be specifically described as follows.

[0067] First, the quantum bit 110 is coupled to the amplifier circuit 120 through the coupling end 140; wherein the quantum bit 110 is a two-energy-level system, and the low energy level can be used as the state |0>, and the high energy level can be used as the state |1>; when the state of the quantum bit 110 is superimposed, the quantum bit 110 has the states |0> and |1> at the same time, and the quantum bit 110 can also collapse into one of the states, that is, the two ground states of the quantum bit 110 are the ground state |0> and the ground state |1>.

[0068] Then, by sending a microwave signal of a specific signal frequency through the measurement input terminal 150, the amplifier circuit 120 can absorb photons when the quantum bit 110 is in the ground state |1>, but the amplifier circuit 120 does not absorb photons when the quantum bit 110 is in the ground state |0>. This is equivalent to mapping the ground state |0> and the ground state |1> of the quantum bit 110 to whether the amplifier circuit 120 absorbs photons.

[0069] Finally, the amplifier circuit 120 absorbs photons and transitions to a high energy level, and then jumps to another frequency. The output target voltage signal is measured by measuring the output terminal 160, and the frequency of the amplifier circuit 120 is determined by the target voltage signal. Then, the state of the quantum bit 110 is determined by the frequency of the amplifier circuit 120, and the state of the quantum bit 110 can be effectively measured.

[0070] On this basis, the first linear inductor module 122 and the second linear inductor module 123 are connected in series, and the Josephson junction 124 is connected in parallel with the second linear inductor module 123, which is equivalent to the Josephson junction 124 being connected in series with the first linear inductor module 122. The impedance of the first linear inductor module 122 is related to the frequency. Within a certain frequency range, the impedance of the first linear inductor module 122 changes linearly. By reasonably selecting the parameters of the first linear inductor module 122, it can be ensured that the first linear inductor module 122 exhibits a linear impedance characteristic within a specific operating frequency range. Under the action of the first linear inductor module 122, the nonlinearity of the amplifier circuit 120 can be reduced. While meeting the amplification requirements, the coupling between the amplifier circuit 120 and the outside world is reduced, thereby reducing the energy leakage of the quantum bit 110 and improving the accuracy of the measurement results. In addition, the amplifier circuit 120 can be directly coupled with the quantum bit 110, eliminating the need for other intermediate devices, thereby reducing the circuit complexity of the state measurement of the quantum bit 110.

[0071] Specifically, referring to FIG2 , FIG2 is an optional potential energy schematic diagram of an amplifier circuit provided in an embodiment of the present application. As shown in FIG2 , the potential energy schematic diagram of the amplifier circuit includes two potential wells. During the process of the potential well 201 on the left side of the figure, the amplifier circuit absorbs photons and transitions from the local minimum of the metastable state to a high energy level; then, during the process of the potential well 202 on the right side of the figure, it jumps to another frequency. The voltage signal of the amplifier circuit coupled to the measurement input terminal is measured by the measurement input terminal, and the frequency of the amplifier circuit is determined by the voltage signal. The state of the quantum bit can be determined by the frequency of the amplifier circuit.

[0072] In an embodiment of the present application, a quantum circuit includes a quantum bit, an amplifier circuit, a coupling end, a measurement input end, and a measurement output end; wherein the amplifier circuit may include a capacitor module, a first linear inductor module, a second linear inductor module, and a Josephson junction; at this time, the quantum bit, the measurement input end, and the measurement output end are respectively coupled to the same coupling end.

[0073] For example, referring to FIG3 , FIG3 is an optional circuit schematic diagram of a quantum circuit provided in an embodiment of the present application. As shown in FIG3 , a quantum bit is formed by a capacitor 303 and a Josephson junction 304 in parallel, one end of the capacitor 303 is coupled to the coupling end 301 through a capacitor 305, the other end of the capacitor 303 is connected to the ground end 302, the measurement input end 306 is coupled to the coupling end 301 through a capacitor 307, and the measurement output end 312 is coupled to the coupling end 301 through a capacitor 307; the capacitor module is a capacitor 308, the first linear inductor module is an inductor 309, and the second linear inductor module is an inductor 310, one end of the capacitor 308 is connected to the coupling end 301, the other end of the capacitor 308 is connected to the ground end 302, one end of the inductor 309 is connected to the coupling end 301, the other end of the inductor 309 is connected to one end of the inductor 310, the other end of the inductor 310 is connected to the ground end 302, and the Josephson junction 311 is connected in parallel to both ends of the inductor 310. Among them, quantum bits can also be formed in other forms, which are not limited in the embodiments of the present application.

[0074] In an embodiment of the present application, the number of amplifying circuits and coupling ends in the quantum circuit can both be two, the two amplifying circuits share the same Josephson junction, and the capacitor module and the first linear inductor module of each amplifying circuit are respectively connected to their corresponding coupling ends.

[0075] It should be noted that the quantum circuit includes two amplification circuits, which are two-mode amplification circuits, that is, the quantum circuit has a dual-mode structure; in the quantum circuit with a dual-mode structure, the two-mode amplification circuits share the same Josephson junction, and tunneling will occur simultaneously; since the capacitor module and the first linear inductance module of each amplification circuit are respectively connected to their corresponding coupling ends, that is, the quantum circuit includes two mutually isolated coupling ends, which reduces the mutual influence between the two coupling ends, thereby reducing the signal interference between the two coupling ends; under the isolation effect of the two coupling ends, the quantum bit is isolated from the external environment, and the quantum bit cannot directly leak energy to the external environment through the second-mode amplification circuit, which can effectively protect the quantum bit; in addition, under the coupling effect of one of the coupling ends, one of the capacitor modules, one of the second linear inductance modules and the Josephson junction form a resonant circuit, and under the coupling effect of the other coupling end, the other capacitor module, the other second linear inductance module and the Josephson junction also form a resonant circuit. Therefore, the quantum circuit with a dual-mode structure provided with a resonant circuit can amplify the signal of the quantum bit, and thus can effectively measure the state of the quantum bit.

[0076] Exemplarily, the process of measuring the quantum bit state can be specifically described as follows.

[0077] First, the amplifier circuit of the first mode is coupled to the quantum bit through the corresponding coupling end, and the amplifier circuit of the second mode is coupled to the measurement input end through the corresponding coupling end. At the same time, the amplifier circuit of the second mode is also coupled to the measurement output end through the corresponding coupling end. Among them, the quantum bit is a two-energy-level system, and the low energy level can be used as the state |0>, and the high energy level can be used as the state |1>. When the state of the quantum bit is superimposed, the quantum bit has the states |0> and |1> at the same time. The quantum bit can also collapse into one of the states, that is, the two ground states of the quantum bit are ground state |0> and ground state |1> respectively.

[0078] Then, by inputting a microwave signal of a specific frequency into the input port, the amplifier circuit can absorb photons when the qubit is in the ground state |1>, but not when the qubit is in the ground state |0>. This is equivalent to mapping the qubit's ground state |0> and ground state |1> to whether the amplifier circuit, which is the first mode directly coupled to the qubit, can absorb photons.

[0079] Finally, after the first-mode amplifier circuit directly coupled to the quantum bit absorbs a photon, it will cause the frequencies of the two-mode amplifier circuits to jump simultaneously. By obtaining the target voltage signal of the second-mode amplifier circuit coupled to the measurement input end through the measurement input end, and then determining the frequency of the second-mode amplifier circuit, effective measurement of the quantum bit state can be achieved.

[0080] In an embodiment of the present application, the two amplifying circuits of the quantum circuit include a first amplifying circuit and a second amplifying circuit, and the two coupling terminals include a first coupling terminal and a second coupling terminal. One end of a capacitor module in the first amplifying circuit is connected to the first coupling terminal, and the other end of the capacitor module in the first amplifying circuit is connected to the ground terminal; one end of a capacitor module in the second amplifying circuit is connected to the second coupling terminal, and the other end of the capacitor module in the second amplifying circuit is connected to the ground terminal; one end of a first linear inductor module in the first amplifying circuit is connected to the first coupling terminal, and one end of the first linear inductor module in the second amplifying circuit is connected to the second coupling terminal.

[0081] In an embodiment of the present application, when the first amplifier circuit and the second amplifier circuit in the quantum circuit share the same second linear inductor module, one end of the second linear inductor module is connected to the other end of the first linear inductor module in the first amplifier circuit and the other end of the first linear inductor module in the second amplifier circuit, and the other end of the second linear inductor module is connected to the ground end.

[0082] It should be noted that in a quantum circuit with a dual-mode structure, the first amplification circuit and the second amplification circuit not only share the same Josephson junction, but also share the same second linear inductance module; in this case, the quantum circuit includes a first coupling end, a second coupling end, two capacitor modules, two first linear inductance modules, a second linear inductance module and a Josephson junction, the two first linear inductance modules are connected to the same second linear inductance module, and the Josephson junction is connected in parallel with the second linear inductance module.

[0083] Based on this, since the first amplifying circuit and the second amplifying circuit share the same second linear inductor module, the circuit complexity of quantum bit measurement can be reduced; the first amplifying circuit and the second amplifying circuit share the same Josephson junction, and tunneling will occur simultaneously; since the two capacitor modules are respectively connected to their corresponding coupling ends, and the two first linear inductor modules are also respectively connected to their corresponding coupling ends, the signals between the first coupling end and the second coupling end will not interfere with each other. Under the isolation effect of the two coupling ends and the two amplifying circuits, the quantum bit is isolated from the external environment, and the quantum bit cannot directly leak energy to the external environment through the mode amplifying circuit in the second amplifying circuit, which can effectively protect the quantum bit; in addition, the two amplifying circuits each form their own resonant loop. Therefore, the quantum circuit with a dual-mode structure provided with a resonant loop can amplify the signal of the quantum bit, and thus can effectively measure the quantum bit state, reducing additional measurement conversion steps.

[0084] For example, referring to FIG4 , FIG4 is a second optional circuit schematic diagram of a quantum circuit provided in an embodiment of the present application. As shown in FIG4 , a quantum bit is formed by a capacitor 404 and a Josephson junction 405 connected in parallel. One end of the capacitor 404 is coupled to the first coupling end 401 through a capacitor 406, and the other end of the capacitor 404 is connected to the ground end 403. The measurement input end 407 is coupled to the second coupling end 402 through a capacitor 408, and the measurement output end 409 is coupled to the second coupling end 402 through a capacitor 408. The capacitor module in the first amplifying circuit is a capacitor 410, the capacitor module in the second amplifying circuit is a capacitor 411, the first linear inductor module in the first amplifying circuit is an inductor 412, and the first linear inductor module in the second amplifying circuit is an inductor 413. The first linear inductor module is inductor 413, and the second linear inductor module is inductor 414; one end of capacitor 410 is connected to the first coupling end 401, and the other end of capacitor 410 is connected to the ground end 403; one end of capacitor 411 is connected to the second coupling end 402, and the other end of capacitor 411 is connected to the ground end 403; one end of inductor 412 is connected to the first coupling end 401, and one end of inductor 413 is connected to the second coupling end 402; one end of inductor 414 is connected to the other end of inductor 412 and the other end of inductor 413, and the other end of inductor 414 is connected to the ground end 403; a Josephson junction 415 is connected in parallel to both ends of inductor 414.

[0085] In an embodiment of the present application, when the first amplifier circuit and the second amplifier circuit in the quantum circuit respectively include their own second linear inductor modules, the other end of the first linear inductor module in the first amplifier circuit is connected to one end of the second linear inductor module in the first amplifier circuit, and the other end of the second linear inductor module in the first amplifier circuit is connected to the ground end; the other end of the first linear inductor module in the second amplifier circuit is connected to one end of the second linear inductor module in the second amplifier circuit, and the other end of the second linear inductor module in the second amplifier circuit is connected to the ground end.

[0086] It should be noted that in a quantum circuit with a dual-mode structure, the first amplification circuit and the second amplification circuit only share the same Josephson junction; wherein the quantum circuit includes a first coupling end, a second coupling end, two capacitor modules, two first linear inductance modules, two second linear inductance modules and a Josephson junction, the two first linear inductance modules are respectively connected to different second linear inductance modules, and the two second linear inductance modules are both connected in parallel with the Josephson junction.

[0087] It can be understood that since the first amplifying circuit and the second amplifying circuit respectively include their own capacitor modules, first linear inductance modules and second linear inductance modules, the two capacitor modules are respectively connected to their respective corresponding coupling ends, and the two first linear inductance modules are also respectively connected to their respective corresponding coupling ends; and since the signals between the two coupling ends will not interfere with each other, under the isolation effect of the two coupling ends and the two amplifying circuits, the quantum bits are isolated from the external environment, and the quantum bits cannot directly leak energy to the external environment through the second mode amplifying circuit. Therefore, the quantum bits can be effectively protected; in addition, the first amplifying circuit and the second amplifying circuit each form their own resonant circuit. Therefore, the quantum circuit with a dual-mode structure provided with a resonant circuit can amplify the signal of the quantum bit, and thus can effectively measure the state of the quantum bit, while reducing additional measurement conversion steps.

[0088] For example, referring to FIG5 , FIG5 is a third optional circuit schematic diagram of a quantum circuit provided in an embodiment of the present application. As shown in FIG5 , a quantum bit is formed by a capacitor 504 and a Josephson junction 505 connected in parallel, one end of the capacitor 504 is coupled to the first coupling end 501 through a capacitor 506, the other end of the capacitor 504 is connected to the ground end 503, the measurement input end 507 is coupled to the second coupling end 502 through a capacitor 508, and the measurement output end 509 is coupled to the second coupling end 502 through a capacitor 508; the capacitor module in the first amplifying circuit is a capacitor 511, the capacitor module in the second amplifying circuit is a capacitor 512, the first linear inductance module in the first amplifying circuit is an inductor 513, the first linear inductance module in the second amplifying circuit is an inductor 514, the second linear inductance module in the first amplifying circuit is an inductor 515, and the second amplifying circuit is an inductor 516. The second linear inductor module in the circuit is inductor 516, one end of capacitor 511 is connected to the first coupling end 501, and the other end of capacitor 511 is connected to the ground end 503; one end of capacitor 512 is connected to the second coupling end 502, and the other end of capacitor 512 is connected to the ground end 503; one end of inductor 513 is connected to the first coupling end 501, and the other end of inductor 513 is connected to one end of inductor 515, and the other end of inductor 515 is connected to the ground end 503; one end of inductor 514 is connected to the second coupling end 502, and the other end of inductor 514 is connected to one end of inductor 516, and the other end of inductor 516 is connected to the ground end 503. Josephson junction 517 is connected in parallel to both ends of inductor 515, and Josephson junction 517 is also connected in parallel to both ends of inductor 516.

[0089] In an embodiment of the present application, the quantum circuit further includes a third linear inductor module and a current input terminal for inputting current into the third linear inductor module. The third linear inductor module is mutually inductively connected to the second linear inductor module, and the third linear inductor module is connected to the current input terminal.

[0090] It should be noted that the impedance of the third linear inductor module is related to the frequency. Within a certain frequency range, the impedance of the third linear inductor module changes linearly. By reasonably selecting the parameters of the third linear inductor module, it can be ensured that the third linear inductor module presents a linear impedance characteristic within a specific operating frequency range. Since the second linear inductor module and the Josephson junction are in a parallel state in the resonant circuit, and the third linear inductor module is mutually inductively connected to the second linear inductor module, the current state of the third linear inductor module can be adjusted through the current input end, thereby adjusting the electromagnetic coupling effect between the second linear inductor module and the third linear inductor module to adjust the resonant frequency of the resonant circuit, which is equivalent to the third linear inductor module and the current input end forming a magnetic flux bias circuit. The magnetic flux bias circuit can bias the resonant circuit. When the resonant circuit is properly biased, the amplifying circuit can absorb photons when the quantum bit is in the second state, and the amplifying circuit does not absorb photons when the quantum bit is in the first state.

[0091] It can be understood that when the quantum circuit includes an amplification circuit and a coupling end, the quantum circuit may include a coupling end, a capacitor module, a first linear inductor module, a second linear inductor module and a Josephson junction; under the action of the coupling end, the capacitor module, the second linear inductor module and the Josephson junction form a resonant circuit; at this time, the quantum circuit also includes a third linear inductor module and a current input end, and the third linear inductor module is mutually inductively connected to the second linear inductor module. The current state of the third linear inductor module can be adjusted through the current input end, thereby adjusting the electromagnetic coupling effect between the second linear inductor module and the third linear inductor module; in this way, the resonant frequency of the resonant circuit can be effectively adjusted, which is equivalent to effectively biasing the resonant circuit.

[0092] In an embodiment of the present application, when the quantum circuit includes two amplification circuits and two coupling ends, the quantum circuit may include a first coupling end, a second coupling end, two capacitor modules, two first linear inductor modules, a second linear inductor module and a Josephson junction; in this case, the quantum circuit has a dual-mode structure. Under the coupling action of the first coupling end, the capacitor module in the first amplifier circuit, the second linear inductor module in the first amplifier circuit, and the Josephson junction form a resonant circuit; under the coupling action of the second coupling end, the capacitor module in the second amplifier circuit, the second linear inductor module in the second amplifier circuit, and the Josephson junction also form a resonant circuit; at this time, the quantum circuit also includes two third linear inductor modules and two current input ends, one of which is used to input current to one of the third linear inductor modules, and the other current input end is used to input current to the other third linear inductor module, one of which is mutually inductively connected to the second linear inductor module in the first amplifier circuit, and the other current input end is mutually inductively connected to the second linear inductor module in the second amplifier circuit; here, the current state of the corresponding third linear inductor module can be adjusted through the current input end, thereby adjusting the electromagnetic coupling effect between the corresponding second linear inductor module and the corresponding third linear inductor module, which can effectively adjust the resonant frequency of the corresponding resonant circuit, which is equivalent to effectively biasing the resonant circuit.

[0093] In an embodiment of the present application, the capacitor module in the quantum circuit includes distributed capacitors, and the amplification circuit is manufactured using a planar process.

[0094] It should be noted that the amplifier circuit is prepared using a planar process, which can be divided into two categories: physical preparation methods and chemical preparation methods. Among them, the physical preparation method refers to the physical process of sputtering atoms on the surface of a material by thermal evaporation or particle bombardment, to achieve the material transfer of material atoms from the source material to the surface of the substrate material, such as physical vapor deposition (PVD), spin coating, electroplating, etc.; the chemical preparation method refers to introducing the vapor of a gaseous reactant or liquid reactant containing thin film elements into the process chamber with a reasonable airflow, causing a chemical reaction on the substrate surface and depositing a thin film on the substrate surface, such as chemical vapor deposition (CVD) and epitaxy, etc.; in the process of preparing amplifier devices, physical preparation methods and chemical preparation methods can complement each other. The physical preparation method can be used to deposit metal wires and metal compound films, etc., and the physical preparation method can be used to deposit insulating materials through reactions between different gases.

[0095] It can be understood that distributed capacitance refers to capacitors that are dispersed or distributed over a larger area or volume (larger than a specified area or volume), and have the properties of capacitance distributed between circuit elements; in an amplifier circuit prepared using a planar process, the use of distributed capacitance can optimize circuit performance, effectively utilize space, and reduce the physical size of the amplifier device.

[0096] In an embodiment of the present application, in a quantum circuit, the capacitor module, the first linear inductor module, the second linear inductor module, and the Josephson junction in the amplifier circuit are integrated into the same device; or, the capacitor module, the second linear inductor module, and the Josephson junction in the amplifier circuit are integrated into the same device, and the first linear inductor module in the amplifier circuit belongs to another device.

[0097] 6 , which is a schematic diagram of an optional structure of an amplifier device provided in an embodiment of the present application, the amplifier device includes an amplifier circuit 610, a ground terminal 620, and a coupling terminal 630. The amplifier circuit 610 includes a capacitor module 611, a first linear inductor module 612, a second linear inductor module 613, and a Josephson junction 614. One end of the capacitor module 611 is connected to the coupling terminal 630, and the other end of the capacitor module 611 is connected to the ground terminal 620. One end of the first linear inductor module 612 is connected to the coupling terminal 630, and the other end of the first linear inductor module 612 is connected to one end of the second linear inductor module 613, and the other end of the second linear inductor module 613 is connected to the ground terminal 620. The Josephson junction 614 is connected in parallel to both ends of the second linear inductor module 613.

[0098] It should be noted that the coupling end 630 refers to a port in a circuit where multiple electrical components are interconnected or influence each other; the amplifier circuit 610 includes a capacitor module 611, a first linear inductor module 612, a second linear inductor module 613, and a Josephson junction 614, and the Josephson junction 614 can be used as a nonlinear inductor module; since the Josephson junction 614 and the second linear inductor module 613 are connected in parallel, and the coupling end 630, the first linear inductor module 612, the second linear inductor module 613, and the ground end 620 are connected in series in sequence, and the coupling end 630, the capacitor module 611, and the ground end 620 are connected in series in sequence, under the action of the coupling end 630, the capacitor module 611, the second linear inductor module 613, and the Josephson junction 614 form a resonant circuit; the amplifier device provided with a resonant circuit can amplify the signal of the quantum bit, and thus can effectively measure the state of the quantum bit.

[0099] Based on FIG6 , the measurement process of the quantum bit state can be specifically described as follows.

[0100] First, the quantum bit is coupled to the amplifier circuit 610 through the coupling end 630; wherein the quantum bit is a two-energy-level system, the low energy level can be used as the state |0>, and the high energy level can be used as the state |1>. When the states of the quantum bit are superimposed, the quantum bit has the states |0> and |1> at the same time. The quantum bit can also collapse into one of the states, that is, the two ground states of the quantum bit are ground state |0> and ground state |1>.

[0101] Then, a microwave signal of a specific signal frequency is sent to the amplifier circuit 610, so that the amplifier circuit 610 can absorb photons when the quantum bit is in the ground state |1>, but the amplifier circuit 610 does not absorb photons when the quantum bit is in the ground state |0>. This is equivalent to mapping the ground state |0> and ground state |1> of the quantum bit to whether the amplifier circuit 610 absorbs photons.

[0102] Finally, the amplifier circuit 610 absorbs photons and transitions to a high energy level, and then jumps to another frequency; by measuring the frequency of the amplifier circuit 610 to determine the state of the quantum bit, the quantum bit state can be effectively measured.

[0103] It can be understood that connecting the first linear inductor module 612 and the second linear inductor module 613 in series, and connecting the Josephson junction 614 in parallel with the second linear inductor module 613, is equivalent to connecting the Josephson junction 614 in series with the first linear inductor module 612. The impedance of the first linear inductor module 612 is related to the frequency. Within a certain frequency range, the impedance of the first linear inductor module 612 varies linearly. By reasonably selecting the parameters of the first linear inductor module 612, it can be ensured that the first linear inductor module 612 exhibits a linear impedance characteristic within a specific operating frequency range. Under the action of the first linear inductor module 612, the nonlinearity of the amplifier circuit 610 can be reduced. While meeting the amplification requirements, the coupling between the amplifier circuit 610 and the outside world is reduced, thereby reducing the energy leakage of the quantum bit and improving the accuracy of the measurement result. In addition, the amplifier circuit 610 can be directly coupled with the quantum bit, reducing the setting of other intermediate devices, thereby reducing the circuit complexity of the quantum bit measurement.

[0104] In an embodiment of the present application, the amplifier device includes an amplifier circuit, a coupling terminal and a ground terminal; wherein the amplifier circuit includes a capacitor module, a first linear inductor module, a second linear inductor module and a Josephson junction.

[0105] Specifically, referring to Figure 7, Figure 7 is a first optional circuit schematic diagram of an amplifier device provided in an embodiment of the present application. As shown in Figure 7, the capacitor module is a capacitor 703, the first linear inductor module is an inductor 704, and the second linear inductor module is an inductor 705; one end of capacitor 703 is connected to coupling terminal 701, and the other end of capacitor 703 is connected to ground terminal 702; one end of inductor 704 is connected to coupling terminal 701, and the other end of inductor 704 is connected to one end of inductor 705, and the other end of inductor 705 is connected to ground terminal 702; and a Josephson junction 706 is connected in parallel to both ends of inductor 705.

[0106] In the embodiment of the present application, the number of amplifier circuits and coupling ends in the amplifier device is two, the two amplifier circuits share the same Josephson junction, and the capacitor module and the first linear inductor module of each amplifier circuit are respectively connected to their corresponding coupling ends.

[0107] In an embodiment of the present application, the two amplifier circuits in the amplifier device include a first amplifier circuit and a second amplifier circuit, and the two coupling ends include a first coupling end and a second coupling end; one end of the capacitor module in the first amplifier circuit is connected to the first coupling end, and the other end of the capacitor module in the first amplifier circuit is connected to the ground end; one end of the capacitor module in the second amplifier circuit is connected to the second coupling end, and the other end of the capacitor module in the second amplifier circuit is connected to the ground end; one end of the first linear inductor module in the first amplifier circuit is connected to the first coupling end; and one end of the first linear inductor module in the second amplifier circuit is connected to the second coupling end.

[0108] In an embodiment of the present application, when the first amplifier circuit and the second amplifier circuit share the same second linear inductor module, the other end of the first linear inductor module in the first amplifier circuit is respectively connected to one end of the second linear inductor module and one end of the Josephson junction, and the other end of the second linear inductor module and the other end of the Josephson junction are respectively connected to the ground end; the other end of the first linear inductor module in the second amplifier circuit is connected to one end of the second linear inductor module and one end of the Josephson junction.

[0109] It should be noted that in an amplifier device with a dual-mode structure, the first amplifier circuit and the second amplifier circuit share not only the same Josephson junction but also the same second linear inductor module. In this case, the amplifier device includes a first coupling end, a second coupling end, two capacitor modules, two first linear inductor modules, a second linear inductor module and a Josephson junction. The two first linear inductor modules are connected to the same second linear inductor module, and the Josephson junction is connected in parallel with the second linear inductor module.

[0110] Based on this, since the first amplifying circuit and the second amplifying circuit share the same second linear inductor module, the circuit complexity of quantum bit measurement can be reduced; the first amplifying circuit and the second amplifying circuit share the same Josephson junction, and tunneling will occur simultaneously; since the two capacitor modules are respectively connected to their corresponding coupling ends, and the two first linear inductor modules are also respectively connected to their corresponding coupling ends, the signals between the first coupling end and the second coupling end will not interfere with each other. Under the isolation effect of the two coupling ends and the two amplifying circuits, the quantum bit is isolated from the external environment, and the quantum bit cannot directly leak energy to the external environment through the mode amplifying circuit in the second amplifying circuit, which can effectively protect the quantum bit; in addition, the two amplifying circuits each form their own resonant loop, so the amplifier device with a dual-mode structure provided with a resonant loop can amplify the signal of the quantum bit, and thus can effectively measure the quantum bit state, reducing additional measurement conversion steps.

[0111] For example, referring to FIG8 , FIG8 is a second optional circuit schematic diagram of the amplifier device provided in an embodiment of the present application. As shown in FIG8 , the capacitor module in the first amplifier circuit is capacitor 804, the capacitor module in the second amplifier circuit is capacitor 805, the first linear inductor module in the first amplifier circuit is inductor 806, the first linear inductor module in the second amplifier circuit is inductor 807, and the second linear inductor module is inductor 808; one end of capacitor 804 is connected to the first coupling end 801, and the other end of capacitor 804 is connected to the ground end 803; one end of capacitor 805 is connected to the second coupling end 802, and the other end of capacitor 805 is connected to the ground end 803; one end of inductor 806 is connected to the first coupling end 801, one end of inductor 807 is connected to the second coupling end 802, one end of inductor 808 is connected to the other end of inductor 806 and the other end of inductor 807, and the other end of inductor 808 is connected to the ground end 803; and a Josephson junction 809 is connected in parallel to both ends of inductor 808.

[0112] In an embodiment of the present application, when the first amplifier circuit and the second amplifier circuit in the amplifier device respectively include their own second linear inductor modules, the other end of the first linear inductor module in the first amplifier circuit is connected to one end of the second linear inductor module in the first amplifier circuit, and the other end of the second linear inductor module in the first amplifier circuit is connected to the ground end; the other end of the first linear inductor module in the second amplifier circuit is connected to one end of the second linear inductor module in the second amplifier circuit, and the other end of the second linear inductor module in the second amplifier circuit is connected to the ground end.

[0113] It should be noted that in an amplifier device with a dual-mode structure, the first amplifier circuit and the second amplifier circuit only share the same Josephson junction; wherein the amplifier device includes a first coupling end, a second coupling end, two capacitor modules, two first linear inductor modules, two second linear inductor modules and a Josephson junction, the two first linear inductor modules are respectively connected to different second linear inductor modules, and the two second linear inductor modules are both connected in parallel with the Josephson junction.

[0114] It can be understood that since the first amplifying circuit and the second amplifying circuit respectively include their own capacitor modules, first linear inductance modules and second linear inductance modules, the two capacitor modules are respectively connected to their respective corresponding coupling ends, and the two first linear inductance modules are also respectively connected to their respective corresponding coupling ends; and since the signals between the two coupling ends will not interfere with each other, under the isolation effect of the two coupling ends and the two amplifying circuits, the quantum bits are isolated from the external environment, and the quantum bits cannot directly leak energy to the external environment through the second mode amplifying circuit. Therefore, the quantum bits can be effectively protected; in addition, the first amplifying circuit and the second amplifying circuit each form their own resonant circuit. Therefore, the dual-mode structure amplifier device with a resonant circuit can amplify the signal of the quantum bit, and thus can effectively measure the state of the quantum bit, while reducing additional measurement conversion steps.

[0115] For example, referring to FIG9 , FIG9 is a third optional circuit schematic diagram of the amplifier device provided in an embodiment of the present application. As shown in FIG9 , the capacitor module in the first amplifier circuit is capacitor 904, the capacitor module in the second amplifier circuit is capacitor 905, the first linear inductor module in the first amplifier circuit is inductor 906, the first linear inductor module in the second amplifier circuit is inductor 907, the second linear inductor module in the first amplifier circuit is inductor 908, and the second linear inductor module in the second amplifier circuit is inductor 909. One end of capacitor 904 is connected to the first coupling end 901, and the other end of capacitor 904 is connected to the ground end 903; one end of capacitor 905 is connected to the ground end 904. The second coupling terminal 902 is connected, and the other end of the capacitor 905 is connected to the ground terminal 903; one end of the inductor 906 is connected to the first coupling terminal 901, and the other end of the inductor 906 is connected to one end of the inductor 908, and the other end of the inductor 908 is connected to the ground terminal 903; one end of the inductor 907 is connected to the second coupling terminal 902, and the other end of the inductor 907 is connected to one end of the inductor 909, and the other end of the inductor 909 is connected to the ground terminal 903. A Josephson junction 910 is connected in parallel to both ends of the inductor 908, and the Josephson junction 910 is also connected in parallel to both ends of the inductor 909.

[0116] In an embodiment of the present application, the amplifier device further includes a third linear inductor module and a current input end for inputting current into the third linear inductor module. The third linear inductor module is mutually inductively connected to the second linear inductor module, and the third linear inductor module is connected to the current input end.

[0117] It can be understood that when the amplifier device includes an amplifier circuit and a coupling end, that is, the amplifier device can include a coupling end, a capacitor module, a first linear inductor module, a second linear inductor module and a Josephson junction; under the action of the coupling end, the capacitor module, the second linear inductor module and the Josephson junction form a resonant circuit; at this time, the amplifier device also includes a third linear inductor module and a current input end, and the third linear inductor module is mutually inductively connected to the second linear inductor module. The current state of the third linear inductor module can be adjusted through the current input end, thereby adjusting the electromagnetic coupling effect between the second linear inductor module and the third linear inductor module; in this way, the resonant frequency of the resonant circuit can be effectively adjusted, which is equivalent to effectively biasing the resonant circuit.

[0118] In an embodiment of the present application, when the amplifying device includes two amplifying circuits and two coupling ends, that is, the amplifying device may include a first coupling end, a second coupling end, two capacitor modules, two first linear inductor modules, a second linear inductor module and a Josephson junction; in this case, the amplifying device has a dual-mode structure. Under the coupling action of the first coupling end, the capacitor module in the first amplifier circuit, the second linear inductor module in the first amplifier circuit, and the Josephson junction form a resonant circuit. Under the coupling action of the second coupling end, the capacitor module in the second amplifier circuit, the second linear inductor module in the second amplifier circuit, and the Josephson junction also form a resonant circuit. At this time, the amplifier device also includes two third linear inductor modules and two current input ends, one of which is used to input current to one of the third linear inductor modules, and the other current input end is used to input current to the other third linear inductor module. One current input end is mutually inductively connected to the second linear inductor module in the first amplifier circuit, and the other current input end is mutually inductively connected to the second linear inductor module in the second amplifier circuit. Here, the current state of the corresponding third linear inductor module can be adjusted through the current input end, thereby adjusting the electromagnetic coupling effect between the corresponding second linear inductor module and the corresponding third linear inductor module, which can effectively adjust the resonant frequency of the corresponding resonant circuit, which is equivalent to effectively biasing the resonant circuit.

[0119] In the embodiment of the present application, the capacitor module in the amplifier device includes distributed capacitors, and the amplifier circuit is manufactured using a planar process.

[0120] It can be understood that distributed capacitance refers to capacitors that are dispersed or distributed over a large area or volume, and have the properties of capacitance distributed between circuit elements; in amplifier devices prepared using planar technology, the use of distributed capacitance can optimize circuit performance, effectively utilize space, and reduce the physical size of the amplifier device.

[0121] In an embodiment of the present application, the capacitor module, the first linear inductor module, the second linear inductor module and the Josephson junction in the amplifier circuit of the amplifier device are integrated into the same device; or, the capacitor module, the second linear inductor module and the Josephson junction in the amplifier circuit of the amplifier device are integrated into the same device, and the first linear inductor module in the amplifier circuit belongs to another device.

[0122] An embodiment of the present application provides a chip structure, which includes the above-mentioned quantum circuit, or includes the above-mentioned amplifier device.

[0123] It should be noted that the chip structure is based on the same inventive concept as the above-mentioned quantum circuit or the above-mentioned amplifier device. By setting a capacitor module, a second linear inductor module and a Josephson junction to form a resonant circuit, the signal amplification effect of the quantum bit is achieved, and the quantum bit state is effectively measured; on this basis, a first linear inductor module is further set to reduce the nonlinearity of the amplifier circuit, while meeting the amplification requirements, reducing the coupling between the amplifier circuit and the outside world, thereby reducing the energy leakage of the quantum bit and improving the accuracy of the measurement results; and, the amplifier circuit can be directly coupled with the quantum bit, which can reduce the setting of other intermediate devices and reduce the circuit complexity of the quantum bit measurement.

[0124] It should be noted that a quantum computer can be provided with this chip structure, and quantum bits have the characteristics of superposition and entanglement to improve the computing efficiency of the quantum computer.

[0125] The quantum bit state measurement method provided in the embodiments of the present application can be applied to various scenarios, including but not limited to cloud technology, quantum computing, smart transportation and other scenarios.

[0126] Referring to Figure 10, Figure 10 is an optional flow chart of a method for measuring the state of a quantum bit provided in an embodiment of the present application. The method for measuring the state of a quantum bit can be executed by a processor connected to a measurement output end in a quantum circuit. The method for measuring the state of a quantum bit includes but is not limited to the following steps 1001 to 1003.

[0127] Step 1001: When a microwave signal is input to a measurement input terminal, a target voltage signal outputted from a measurement output terminal is obtained.

[0128] It should be noted that the above-mentioned quantum circuit includes a quantum bit, an amplifier circuit, a ground terminal, a coupling terminal, a measurement input terminal and a measurement output terminal, and the amplifier circuit includes a capacitor module, a first linear inductor module, a second linear inductor module and a Josephson junction.

[0129] Among them, for the quantum circuit, the measurement input end and the measurement output end are respectively coupled with the corresponding coupling end; here, the measurement input end and the measurement output end are respectively coupled with the same coupling end. From the description of the quantum bit of the above two-energy-level system, it can be seen that a microwave signal is input through the measurement input end. When the quantum bit in the quantum circuit is in the second state, the amplifier circuit can absorb photons, and when the quantum bit is in the first state, the amplifier circuit will not absorb photons. This is equivalent to mapping the first state and the second state of the quantum bit to whether the amplifier circuit absorbs photons. The amplifier circuit in the quantum circuit absorbs photons and can transition to a high energy level, and then jump to another frequency. The frequency of the amplifier circuit can be determined by measuring the target voltage signal measured at the output end. The state of the quantum bit is determined by measuring the frequency of the amplifier circuit, which can achieve effective measurement of the quantum bit state.

[0130] Step 1002: Determine a target phase and a target amplitude according to a target voltage signal, and determine a target measurement point in a first coordinate space according to the target phase and the target amplitude.

[0131] Among them, signal processing is performed on the target voltage signal to determine the corresponding target phase and target amplitude; then, a coordinate space of a polar coordinate system is used as the first coordinate space, and the corresponding target measurement point is determined in the first coordinate space based on the target phase and target amplitude.

[0132] For example, assuming that the position of the polar coordinate system is O and the position of the target measurement point is P, the length of the line segment OP is the target amplitude, and the angle between the line segment OP and the polar axis is the target phase; the polar coordinate system can also be converted into a rectangular coordinate system, where the abscissa of the rectangular coordinate system is used to represent the in-phase component (In-phase, I value), and the ordinate of the rectangular coordinate system is used to represent the quadrature component (Quadrature, Q value).

[0133] It can be understood that since the target voltage signal will change with the frequency of the amplifier circuit, the target phase and target amplitude are determined by the target voltage signal, and then the target measurement point is determined by the target phase and target amplitude. The frequency of the amplifier circuit can be determined by the position of the target measurement point in the first coordinate space, and the state of the quantum bit can be determined by the target measurement point.

[0134] Step 1003: Determine the state of the quantum bit according to the affiliation relationship between the target measurement point and the first sample point region or the second sample point region.

[0135] The belonging relationship between the target measurement point and the first sample point area or the second sample point area can be determined in the following manner.

[0136] (1) Method 1: Determine whether the target measurement point is located within the first sample point area or the second sample point area. When the target measurement point is located within the first sample point area, it is determined that the target measurement point belongs to the first sample point area; when the target measurement point is located within the second sample point area, it is determined that the target measurement point belongs to the second sample point area; when the target measurement point is located outside the first sample point area and outside the second sample point area, it is determined that the target measurement point does not belong to either the first sample point area or the second sample point area, and a new target measurement point can be remeasured.

[0137] (2) Method 2: Determine the first distance between the target measurement point and the first sample point area, and determine the second distance between the target measurement point and the second sample point area. When the first distance is less than the second distance, determine that the target measurement point belongs to the first sample point area; when the first distance is greater than the second distance, determine that the target measurement point belongs to the second sample point area; when the first distance is equal to the second distance, determine that the target measurement point does not belong to either the first sample point area or the second sample point area, and choose to re-measure a new target measurement point. Here, the first distance may refer to the distance between the target measurement point and the center of the first sample point area, or the shortest distance between the target measurement point and the edge of the first sample point area, which is not limited in this embodiment of the present application; the second distance may refer to the distance between the target measurement point and the center of the second sample point area, or the shortest distance between the target measurement point and the edge of the second sample point area, which is not limited in this embodiment of the present application.

[0138] In the embodiment of the present application, the attribution relationship between the target measurement point and the first sample point area or the second sample point area may also be determined by other methods, which are not limited in the embodiment of the present application.

[0139] It should be noted that in the first coordinate space, the first sample point region and the second sample point region are respectively used to indicate two different states of the qubit. In a qubit of a two-level system, multiple measurements can be performed in advance on the qubit in the first state, and the first sample point region can be determined based on the region where the measurement points are located. Therefore, the first sample point region can indicate that the qubit is in the first state. Multiple measurements can be performed in advance on the qubit in the second state, and the second sample point region can be determined based on the region where the measurement points are located. Therefore, the second sample point region can indicate that the qubit is in the second state.

[0140] It can be understood that when measuring the state of a quantum bit, the target phase and target amplitude are determined by the target voltage signal, the target measurement point is determined in the corresponding first coordinate space according to the target phase and target amplitude, and the state of the quantum bit is determined according to the affiliation between the target measurement point and the first sample point area or the second sample point area. The state of the quantum bit can be quickly determined by coordinate matching based on the first sample point area and the second sample point area, thereby effectively improving the measurement efficiency of the quantum bit state.

[0141] In an embodiment of the present application, the first sample point area and the second sample point area can be determined by the following steps: determining the signal frequency; setting the state of the quantum bit to the first state, in the first state, whenever the target microwave signal of the signal frequency is input to the measurement input end, obtaining the first sample voltage signal output each time from the measurement output end, determining the first sample measurement point corresponding to the first sample voltage signal in the first coordinate space, and obtaining the first sample point area based on the multiple first sample measurement points; setting the state of the quantum bit to the second state, in the second state, whenever the target microwave signal of the signal frequency is input to the measurement input end, obtaining the second sample voltage signal output each time from the measurement output end, determining the second sample measurement point corresponding to the second sample voltage signal in the first coordinate space, and obtaining the second sample point area based on the multiple second sample measurement points.

[0142] It should be noted that in a two-level qubit, the lower energy level can be in state |0>, and the higher energy level can be in state |1>. When the qubit's states are superimposed, the qubit simultaneously has states |0> and |1>. The qubit can also collapse into one of these states, meaning its two ground states are ground state |0> and ground state |1>. If setting a qubit to the first state refers to setting it to the ground state |0>, then setting it to the second state refers to setting it to the ground state |1>.

[0143] In an embodiment of the present application, when a target microwave signal of a specific signal frequency is sent to the amplifying circuit, the amplifying circuit will not absorb photons when the quantum bit is in the first state, and can absorb photons when the quantum bit is in the second state. This is equivalent to mapping the first state and the second state of the quantum bit to whether the amplifying circuit absorbs photons, and directly encoding the number of photons absorbed by the amplifying circuit through the quantum bit.

[0144] It should be noted that the amplifier circuit can transition to a high energy level by absorbing photons, and then jump to another frequency. By measuring the target voltage signal measured at the output end, the frequency of the amplifier circuit can be determined. By measuring the frequency of the amplifier circuit, the state of the quantum bit can be determined, and effective measurement of the quantum bit state can be achieved.

[0145] It can be understood that in the first coordinate space, the first sample measurement point can be determined by the first sample voltage signal, and the second sample measurement point can be determined by the second sample voltage signal, and the positions of the first sample measurement point and the second sample measurement point in the first coordinate space are different; therefore, before obtaining the target voltage signal output by the measurement output end, the first sample measurement point is located in the first sample point area, and the second sample measurement point is located in the second sample point area in the first coordinate space. Subsequently, based on the first sample point area and the second sample point area, the area to which the target measurement point corresponding to the currently measured target voltage signal belongs can be determined, thereby determining the state of the quantum bit.

[0146] The specific process of determining the first sample point area is described in detail below.

[0147] First, the state of the quantum bit is set to the first state.

[0148] Then, by measuring the target microwave signal with a specific signal frequency input at the input end, the amplification circuit will not absorb photons when the quantum bit is in the first state.

[0149] Then, a corresponding first sample voltage signal is obtained by measuring the output terminal, where the first sample voltage signal is used to indicate that the amplification circuit does not absorb photons when the quantum bit is in the first state.

[0150] Then, the first sample voltage signal is subjected to corresponding signal processing to obtain a corresponding first phase and first amplitude. Here, the first sample voltage signal can be demodulated, sampled, and restored in sequence, and the phase of the restored result is used as the first phase, and the amplitude of the restored result is used as the first amplitude.

[0151] For example, the first sample voltage signal in the time domain is converted into the frequency domain based on Fourier transform, and the phase and amplitude of each frequency component can be determined in the frequency domain.

[0152] Next, a coordinate space of a polar coordinate system is used as a first coordinate space, and a corresponding first sample measurement point is determined in the first coordinate space based on the first phase and the first amplitude; therefore, the first sample measurement point is used to indicate that the amplifier circuit does not absorb photons when the quantum bit is in the first state.

[0153] For example, assuming that the position of the polar coordinate system is O and the position of the first sample measurement point is A, the length of the line segment OA is the first amplitude, and the angle between the line segment OA and the polar axis is the first phase. The polar coordinate system can also be converted into a rectangular coordinate system, where the abscissa of the rectangular coordinate system is used to represent the I value, and the ordinate of the rectangular coordinate system is used to represent the Q value.

[0154] Finally, after multiple measurements, a plurality of first sample measurement points are determined in the first coordinate space; and a first sample point area is determined according to the areas where the plurality of first sample measurement points are located in the first coordinate space.

[0155] For example, a first target bounding box that includes all first sample measurement points is determined in the first coordinate space, and the area within the first target bounding box is used as the first sample point area. In the first coordinate space, there are multiple first candidate bounding boxes that include all first sample measurement points. The first target bounding box is generally the first candidate bounding box with the smallest area. The outline of the first target bounding box can be circular, rectangular, or other shapes. The specific method for determining the first sample point area is not limited in this embodiment of the present application.

[0156] Similarly, the specific process of determining the second sample point area is described in detail below.

[0157] First, the state of the quantum bit is set to the second state.

[0158] Then, by measuring the target microwave signal with a specific signal frequency input at the input end, the amplifier circuit can absorb photons when the quantum bit is in the second state.

[0159] Then, a corresponding second sample voltage signal is obtained by measuring the output end, and the second sample voltage signal is used to indicate that the amplifier circuit can absorb photons when the quantum bit is in the second state.

[0160] Next, the second sample voltage signal is subjected to corresponding signal processing to obtain a corresponding second phase and second amplitude. Here, the second sample voltage signal can be demodulated, sampled, and restored in sequence, and the phase of the restored result is used as the second phase, and the amplitude of the restored result is used as the second amplitude.

[0161] For example, the second sample voltage signal in the time domain is converted into the frequency domain based on Fourier transform, and the phase and amplitude of each frequency component can be determined in the frequency domain.

[0162] Next, a corresponding second sample measurement point is determined in the first coordinate space according to the second phase and the second amplitude; therefore, the second sample measurement point is used to indicate that the amplification circuit can absorb photons when the quantum bit is in the second state.

[0163] For example, assuming that the position of the polar coordinate system is O and the position of the second sample measurement point is B, the length of the line segment OB is the second amplitude, and the angle between the line segment OB and the polar axis is the second phase. The polar coordinate system can also be converted into a rectangular coordinate system, where the abscissa of the rectangular coordinate system is used to represent the I value, and the ordinate of the rectangular coordinate system is used to represent the Q value.

[0164] Finally, after multiple measurements, a plurality of second sample measurement points are determined in the first coordinate space; and then, a second sample point area is determined according to the areas where the plurality of second sample measurement points are located in the first coordinate space.

[0165] For example, a second target bounding box that includes all second sample measurement points is determined in the first coordinate space, and the area within the second target bounding box is used as the second sample point area. In the first coordinate space, there are multiple second candidate bounding boxes that include all second sample measurement points. The second target bounding box is typically the second candidate bounding box with the smallest area. The outline of the second target bounding box can be circular, rectangular, or other shapes. This embodiment of the present application does not limit the specific method for determining the second sample point area.

[0166] For example, referring to FIG11, FIG11 is a schematic diagram of an optional coordinate space for a first sample point region and a second sample point region provided in an embodiment of the present application. As shown in FIG11, in the first coordinate space, the abscissa of the first coordinate space represents the in-phase component, the ordinate of the first coordinate space represents the orthogonal component, the first target bounding box of the first sample point region 1101 is circular, the second target bounding box of the second sample point region 1102 is circular, the first sample point region 1101 may include multiple first sample measurement points 1103, and the second sample point region 1102 may include multiple second sample measurement points 1104. There is no overlapping area between the first sample point region 1101 and the second sample point region 1102.

[0167] Specifically, referring to FIG12 , FIG12 is a schematic diagram of an optional change curve of the device frequency and magnetic flux provided in an embodiment of the present application. As shown in FIG12 , in the second coordinate space, the abscissa of the second coordinate space represents the magnetic flux of the amplifier circuit, and the ordinate of the second coordinate space represents the device frequency of the amplifier circuit; when the device frequency of the amplifier circuit changes with the change of the magnetic flux, under the magnetic flux 1201, the device frequency jumps, indicating that the state of the amplifier circuit has transitioned to another frequency; at this time, the transformation curve of the device frequency and magnetic flux will be divided into two branches, the measurement point corresponding to the left branch is located in the left potential well 1202, and the measurement point corresponding to the right branch is located in the right potential well 1203; therefore, the measurement point corresponding to the left branch can be defined as the first sample measurement point, that is, the point on the left branch is used to determine that the quantum bit is in the first state, and the measurement point corresponding to the right branch can be defined as the second sample measurement point, that is, the point on the right branch is used to determine that the quantum bit is in the second state.

[0168] In an embodiment of the present application, determining the signal frequency can specifically be performed by obtaining curve data of a device frequency of the amplifier circuit changing with a magnetic flux of the amplifier circuit, wherein the curve data includes a first change curve corresponding to a first state and a second change curve corresponding to a second state, and the first change curve and the second change curve are located in the same second coordinate space; obtaining a target frequency corresponding to an intersection of the first change curve and the second change curve; determining a difference between the target frequency and a preset value as the signal frequency, or determining the signal frequency in a frequency interval including the target frequency.

[0169] It should be noted that, under the action of the coupling end, the capacitor module, the second linear inductor module and the Josephson junction in the amplifying circuit form a resonant circuit; the quantum circuit can be provided with a magnetic flux bias circuit composed of a third linear inductor module and a current input end, and then the magnetic flux bias circuit is used to bias the resonant circuit to adjust the resonant frequency of the resonant circuit, so that the amplifying circuit can absorb photons when the quantum bit is in the second state, and the amplifying circuit does not absorb photons when the quantum bit is in the first state.

[0170] Specifically, referring to Figure 13 , which is a schematic diagram of an optional coordinate space for a target frequency according to an embodiment of the present application, when a magnetic flux bias circuit is used to adjust the device frequency of an amplifier circuit, the device frequency of the amplifier circuit can be adjusted using a forward scanning method 1301 or a reverse scanning method 1302. There are two situations as follows.

[0171] Case 1: Set the quantum bit to the first state, adjust the device frequency of the amplifier circuit by forward scanning 1301, and the device frequency of the amplifier circuit will gradually decrease; then set the quantum bit to the second state, adjust the device frequency of the amplifier circuit by reverse scanning 1302, and the device frequency of the amplifier circuit will gradually increase.

[0172] Case 2: The quantum bit is set to the first state, and the device frequency of the amplifier circuit is adjusted by forward scanning 1301, and the device frequency of the amplifier circuit will gradually increase; then the quantum bit is set to the second state, and the device frequency of the amplifier circuit is adjusted by reverse scanning 1302, and the device frequency of the amplifier circuit will gradually decrease.

[0173] To determine the frequency of a microwave signal, the qubit is first set to a first state. The device frequency of the amplifier circuit is then adjusted using a forward scan 1301. During the adjustment process, the magnetic flux state of the amplifier circuit is read, thereby obtaining a first curve showing how the device frequency of the amplifier circuit changes with the magnetic flux of the amplifier circuit.

[0174] Then, the quantum bit is set to the second state, and then the device frequency of the amplifier circuit is adjusted by reverse scanning 1302. During the adjustment process, the magnetic flux state of the amplifier circuit is read, and a second change curve of the device frequency of the amplifier circuit as the magnetic flux of the amplifier circuit changes is obtained.

[0175] Then, the first change curve and the second change curve are placed in the same second coordinate space. The horizontal axis of the second coordinate space represents the magnetic flux of the amplifier circuit, and the vertical axis of the second coordinate space represents the device frequency of the amplifier circuit. The first change curve and the second change curve have an intersection 1303 in the second coordinate space, and the device frequency corresponding to the intersection 1303 is used as the target frequency.

[0176] In an embodiment of the present application, a target frequency or a device frequency near the target frequency can be determined as a signal frequency. Here, the device frequency obtained by subtracting a preset value from the target frequency can be used as the signal frequency; wherein the preset value can be a zero value, a frequency value with a positive sign, or a frequency value with a negative sign. When the preset value is a zero value, the signal frequency is the target frequency. When the preset value is a frequency value with a positive sign, the signal frequency is lower than the target frequency. When the preset value is a frequency value with a negative sign, the signal frequency is higher than the target frequency. It is also possible to first determine a frequency interval containing the target frequency based on the target frequency; for example, the target frequency and a preset first distance value are added to obtain an upper frequency limit, and the target frequency and a preset second distance value are subtracted to obtain a lower frequency limit. Then, a frequency interval is determined based on the upper frequency limit and the lower frequency limit, and a device frequency is randomly selected in the frequency interval as the signal frequency of the microwave signal, so that the amplifier circuit can absorb photons when the quantum bit is in the second state, and the amplifier circuit does not absorb photons when the quantum bit is in the first state.

[0177] In an embodiment of the present application, the target phase and target amplitude are determined based on the target voltage signal. The target voltage signal can be demodulated to obtain a demodulated voltage signal; the demodulated voltage signal is sampled to obtain a sampled voltage signal; the sampled voltage signal is restored to obtain a restored voltage signal; the phase of the restored voltage signal is determined as the target phase, and the amplitude of the restored voltage signal is determined as the target amplitude.

[0178] It should be noted that the target voltage signal is demodulated to obtain a demodulated voltage signal; the demodulation process may include a filtering operation, which is used to filter out noise signals of a specific frequency, thereby reducing the noise and interference of the target voltage signal; the demodulated voltage signal is sampled, and sampling refers to discretizing the continuous demodulated voltage signal in the time domain to obtain a sampled voltage signal; the sampled voltage signal is restored, and restoration refers to reconstructing a continuous representation of the discrete sampled voltage signal, which is equivalent to restoring the original voltage signal to obtain a restored voltage signal; finally, the phase of the restored voltage signal is determined as the target phase, so that the amplitude of the restored voltage signal is determined as the target amplitude, which can improve the accuracy of the target measurement point and thus accurately determine the state of the quantum bit.

[0179] The process of measuring the quantum bit state is described in detail below.

[0180] Specifically, referring to Figure 14 , Figure 14 illustrates an alternative architecture for a method for measuring a quantum bit state provided in an embodiment of the present application. As shown in Figure 14 , the processor for executing the method for measuring a quantum bit state can be provided in computer 1401 . Alternatively, the processor can be integrated into the aforementioned chip structure, which includes a quantum circuit, with the processor connected to a measurement output terminal of the quantum circuit.

[0181] First, curve data of a change in the device frequency of the amplifier circuit as it changes with the magnetic flux of the amplifier circuit is obtained, wherein the curve data includes a first change curve corresponding to a first state and a second change curve corresponding to a second state, and the first change curve and the second change curve are located in the same second coordinate space; a target frequency corresponding to an intersection of the first change curve and the second change curve is obtained; and a difference between the target frequency and a preset value is determined as a signal frequency, or the signal frequency is determined in a frequency interval containing the target frequency.

[0182] Then, the state of the quantum bit is set to a first state. In the first state, whenever a target microwave signal of a signal frequency is input to the measurement input end, a first sample voltage signal outputted by the measurement output end is obtained each time, a first sample measurement point corresponding to the first sample voltage signal in the first coordinate space is determined, and a first sample point area is obtained based on multiple first sample measurement points. The state of the quantum bit is set to a second state. In the second state, whenever a target microwave signal of a signal frequency is input to the measurement input end, a second sample voltage signal outputted by the measurement output end is obtained each time, a second sample measurement point corresponding to the second sample voltage signal in the first coordinate space is determined, and a second sample point area is obtained based on multiple second sample measurement points.

[0183] Then, when a microwave signal is input to the measurement input end to measure the quantum bit 1411, a target voltage signal 1402 output by the measurement output end in the amplifier device 1412 is obtained; the original phase 1403 and the original amplitude 1404 are determined according to the target voltage signal 1402; the target voltage signal is demodulated based on the original phase 1403 and the original amplitude 1404 to obtain a demodulated voltage signal 1405; the demodulated voltage signal 1405 is sampled to obtain a sampled voltage signal 1406; the sampled voltage signal 1406 is restored to obtain a restored voltage signal 1407; the phase of the restored voltage signal 1407 is determined as the target phase 1408, and the amplitude of the restored voltage signal is determined as the target amplitude 1409; and the target measurement point 1410 is determined in the first coordinate space according to the target phase 1408 and the target amplitude 1409.

[0184] Finally, the state of the quantum bit is determined according to the belonging relationship between the target measurement point 1410 and the first sample point area or the second sample point area.

[0185] In an embodiment of the present application, when measuring the state of a quantum bit, a target phase and a target amplitude are determined by a target voltage signal, a target measurement point is determined in a corresponding first coordinate space based on the target phase and the target amplitude, and the state of the quantum bit is determined based on the affiliation between the target measurement point and the first sample point area or the second sample point area. The state of the quantum bit can be quickly determined by coordinate matching based on the first sample point area and the second sample point area, thereby effectively improving the measurement efficiency of the quantum bit state.

[0186] It will be appreciated that, although the various steps in the above-mentioned various flow charts are shown in sequence according to the indication of the arrows, these steps are not necessarily performed in sequence according to the order indicated by the arrows. Unless clearly stated in the present embodiment, the execution of these steps does not have strict order restrictions, and these steps can be performed in other orders. Moreover, at least a portion of the steps in the above-mentioned flow charts can include multiple steps or multiple stages, and these steps or stages are not necessarily performed at the same time, but can be performed at different times, and the execution order of these steps or stages is not necessarily performed in sequence, but can be performed in turn or alternately with at least a portion of the steps or stages in other steps or other steps.

[0187] 15 , which is a schematic diagram of an optional structure of a qubit state measurement device provided in an embodiment of the present application. The qubit state measurement device 1500 is connected to the measurement output terminal of the aforementioned quantum circuit, and includes:

[0188] The signal acquisition module 1501 is configured to acquire a target voltage signal output from the measurement output terminal when a microwave signal is input to the measurement input terminal;

[0189] a signal processing module 1502 configured to determine a target phase and a target amplitude according to the target voltage signal, and determine a target measurement point in a first coordinate space according to the target phase and the target amplitude;

[0190] The state determination module 1503 is configured to determine the state of the quantum bit based on the relationship between the target measurement point and the first sample point area or the second sample point area, where the first sample point area and the second sample point area are preset in the first coordinate space and are respectively used to indicate two different states of the quantum bit.

[0191] In the embodiment of the present application, the measuring device 1500 further includes a frequency determination module, a first measurement module, and a second measurement module;

[0192] a frequency determination module configured as a signal frequency;

[0193] a first measurement module configured to set the state of the qubit to a first state, wherein in the first state, whenever a target microwave signal of a signal frequency is input to the measurement input end, a first sample voltage signal outputted each time by the measurement output end is obtained, a first sample measurement point corresponding to the first sample voltage signal in the first coordinate space is determined, and a first sample point area is obtained based on the plurality of first sample measurement points;

[0194] The second measurement module is configured to set the state of the quantum bit to a second state. In the second state, whenever a target microwave signal of a signal frequency is input to the measurement input end, a second sample voltage signal outputted from the measurement output end is obtained each time, a second sample measurement point corresponding to the second sample voltage signal in the first coordinate space is determined, and a second sample point area is obtained based on the plurality of second sample measurement points.

[0195] In an embodiment of the present application, the above-mentioned frequency determination module is further configured to obtain curve data of the device frequency of the amplifier circuit changing with the magnetic flux of the amplifier circuit, wherein the curve data includes a first change curve corresponding to the first state and a second change curve corresponding to the second state, and the first change curve and the second change curve are located in the same second coordinate space; obtain the target frequency corresponding to the intersection between the first change curve and the second change curve; determine the difference between the target frequency and the preset value as the signal frequency, or determine the signal frequency in a frequency range containing the target frequency.

[0196] In an embodiment of the present application, the signal processing module 1502 is further configured to demodulate the target voltage signal to obtain a demodulated voltage signal; sample the demodulated voltage signal to obtain a sampled voltage signal; restore the sampled voltage signal to obtain a restored voltage signal; determine the phase of the restored voltage signal as the target phase, and determine the amplitude of the restored voltage signal as the target amplitude.

[0197] The above-mentioned device 1500 for measuring the state of a quantum bit and the method for measuring the state of a quantum bit are based on the same inventive concept. By setting a capacitor module, a second linear inductor module and a Josephson junction to form a resonant circuit, the amplification effect of the quantum bit signal is achieved; on this basis, a first linear inductor module is further set to reduce the nonlinearity of the amplifying circuit. While meeting the amplification requirements, the coupling between the amplifying circuit and the outside world is reduced, thereby reducing the energy leakage of the quantum bit and improving the accuracy of the measurement results; and, the amplifying circuit can be directly coupled with the quantum bit, which can reduce the setting of other intermediate devices and reduce the circuit complexity of the quantum bit measurement.

[0198] In addition, when measuring the state of a quantum bit, the target phase and target amplitude are determined by the target voltage signal, the target measurement point is determined in the corresponding first coordinate space according to the target phase and target amplitude, and the state of the quantum bit is determined according to the affiliation between the target measurement point and the first sample point area or the second sample point area. The state of the quantum bit can be quickly determined by coordinate matching based on the first sample point area and the second sample point area, thereby effectively improving the measurement efficiency of the quantum bit state.

[0199] The electronic device for performing the above-mentioned method for measuring the state of a quantum bit provided in an embodiment of the present application may be a terminal. Referring to FIG16 , FIG16 is a partial structural block diagram of a terminal provided in an embodiment of the present application, and the terminal includes components such as a camera assembly 1610, a memory 1620, an input unit 1630, a display unit 1640, a sensor 1650, an audio circuit 1660, a wireless fidelity (Wireless Fidelity, Wi-Fi for short) module 1670, a processor 1680, and a power supply 1690. It will be understood by those skilled in the art that the terminal structure shown in FIG16 does not constitute a limitation on the terminal, and may include more or fewer components than shown, or combine certain components, or arrange the components differently.

[0200] The camera assembly 1610 can be used to capture images or videos. Optionally, the camera assembly 1610 includes a front camera and a rear camera. Typically, the front camera is provided on the front panel of the terminal, and the rear camera is provided on the back of the terminal. In some embodiments, there is at least one rear camera, which is any one of a main camera, a depth of field camera, a wide-angle camera, and a telephoto camera, so as to realize the fusion of the main camera and the depth of field camera to realize the background blur function, the fusion of the main camera and the wide-angle camera to realize panoramic shooting and virtual reality (VR) shooting function or other fusion shooting functions.

[0201] The memory 1620 may be used to store software programs and modules. The processor 1680 executes the software programs and modules stored in the memory 1620 to execute various functional applications and data processing of the terminal.

[0202] The input unit 1630 may be configured to receive input numbers or characters and generate key signals related to the terminal's settings and function control. Specifically, the input unit 1630 may include a touch panel 1631 and other input devices 1632 .

[0203] The display unit 1640 may be configured to display input information or provided information and various menus of the terminal. The display unit 1640 may include a display panel 1641 .

[0204] The audio circuit 1660 , the speaker 1661 , and the microphone 1662 may provide an audio interface.

[0205] The power source 1690 may be AC ​​power, DC power, disposable batteries, or rechargeable batteries.

[0206] The number of sensors 1650 may be one or more, and the one or more sensors 1650 include but are not limited to: an accelerometer, a gyroscope sensor, a pressure sensor, an optical sensor, and the like. The accelerometer can detect the magnitude of acceleration on the three coordinate axes of the coordinate system established by the terminal. For example, the accelerometer can be used to detect the components of gravity acceleration on the three coordinate axes. The processor 1680 can control the display unit 1640 to display the user interface in a horizontal view or a vertical view based on the gravity acceleration signal collected by the accelerometer. The accelerometer can also be used to collect game or user motion data.

[0207] The gyroscope sensor can detect the device's orientation and rotation angle. It can also work with the accelerometer to capture the user's three-dimensional (3D) movements around the device. Processor 1680 uses the data collected by the gyroscope sensor to implement functions such as motion sensing (such as changing the UI based on the user's tilt), image stabilization during shooting, game control, and inertial navigation.

[0208] The pressure sensor can be set on the side frame of the terminal and / or the lower layer of the display unit 1640. When the pressure sensor is set on the side frame of the terminal, it can detect the user's grip signal of the terminal, and the processor 1680 performs left and right hand recognition or shortcut operations based on the grip signal collected by the pressure sensor. When the pressure sensor is set on the lower layer of the display unit 1640, the processor 1680 controls the operability controls on the UI interface based on the user's pressure operation on the display unit 1640. The operability controls include at least one of a button control, a scroll bar control, an icon control, and a menu control.

[0209] The optical sensor is used to collect ambient light intensity. In some embodiments, the processor 1680 can control the display brightness of the display unit 1640 based on the ambient light intensity collected by the optical sensor. Specifically, when the ambient light intensity is high, the display brightness of the display unit 1640 is increased; when the ambient light intensity is low, the display brightness of the display unit 1640 is decreased. In another embodiment, the processor 1680 can also dynamically adjust the shooting parameters of the camera assembly 1610 based on the ambient light intensity collected by the optical sensor.

[0210] In an embodiment of the present application, the processor 1680 included in the terminal can execute the quantum bit state measurement method of the previous embodiment.

[0211] The electronic device for performing the above-mentioned quantum bit state measurement method provided in the embodiment of the present application can also be a server. Referring to FIG17 , FIG17 is a partial structural block diagram of the server provided in the embodiment of the present application. The server 1700 may have relatively large differences due to different configurations or performances, and may include one or more central processing units (CPUs) 1722 (referred to as processors) and memory 1732. Among them, the memory 1732 can be a temporary storage or a permanent storage. The application 1742 stored in the memory 1732 may include one or more modules, each of which may include a series of instruction operations on the server 1700. The memory 1732 also includes data 1744. The CPU 1722 can be configured to communicate with the memory 1732 and execute a series of instruction operations in the memory 1732 on the server 1700.

[0212] The server 1700 may also include one or more power supplies 1726, one or more wired or wireless network interfaces 1750, one or more input and output interfaces 1758, and / or one or more operating systems 1741 (e.g., Windows Server™, Mac OS X™, Unix™, Linux™, FreeBSD™, etc.) stored in the memory 1732.

[0213] The processor in server 1700 can be used to execute the measurement method of the quantum bit state.

[0214] An embodiment of the present application also provides a computer-readable storage medium, which is used to store a computer program, and the program code is used to execute the quantum bit state measurement method of the embodiment of the present application.

[0215] The present application also provides a computer program product, comprising a computer program stored in a computer-readable storage medium. A processor of an electronic device reads the computer program from the computer-readable storage medium and executes the computer program, causing the electronic device to implement the aforementioned method for measuring a quantum bit state.

[0216] The terms "first", "second", and "third" in the specification of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0217] It should be understood that in this application, "at least one" means one or more, and "plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0218] It should be understood that in the description of the embodiments of the present application, multiple (or multiple items) means more than two, greater than, less than, exceed, etc. are understood to exclude the number itself, and above, below, within, etc. are understood to include the number itself.

[0219] In the embodiments of the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of units is only a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interface, device or unit, which can be electrical, mechanical or other forms.

[0220] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the embodiments of the present application.

[0221] In addition, the functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated units may be implemented in the form of hardware or software functional units.

[0222] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a computer program product, which is stored in a computer-readable storage medium and includes a number of instructions for enabling an electronic device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the embodiment method of the present application. The aforementioned computer-readable storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0223] It should also be understood that the various implementation methods provided in the embodiments of the present application can be combined arbitrarily to achieve different technical effects.

[0224] The above is a specific description of the preferred implementation of the present application, but the present application is not limited to the above implementation mode. Technical personnel familiar with the field can also make various equivalent modifications or substitutions under the shared conditions that do not violate the spirit of the present application. These equivalent modifications or substitutions are all included in the scope defined by the claims of the present application.

Claims

1. A quantum circuit, comprising qubits, an amplification circuit, a ground terminal, a coupling terminal, a measurement input terminal, and a measurement output terminal, wherein the amplification circuit includes a capacitance module, a first linear inductance module, a second linear inductance module, and a Josephson junction; One end of the capacitance module is connected to the coupling terminal, and the other end of the capacitance module is connected to the ground terminal; One end of the first linear inductance module is connected to the coupling terminal, the other end of the first linear inductance module is connected to one end of the second linear inductance module, and the other end of the second linear inductance module is connected to the ground terminal; The Josephson junction is connected in parallel across the two ends of the second linear inductance module; The qubits, the measurement input terminal, and the measurement output terminal are connected to the coupling terminal. The measurement input terminal is used to input a microwave signal for measuring the qubits, and the measurement output terminal is used to output a target voltage signal, where the target voltage signal is used to indicate the state of the qubits.

2. The quantum circuit according to claim 1, wherein, The number of the amplification circuits and the coupling terminals is two. The two amplification circuits share the same Josephson junction, and the capacitance modules and the first linear inductance modules of each amplification circuit are respectively connected to their corresponding coupling terminals.

3. The quantum circuit according to claim 2, wherein, The two amplification circuits include a first amplification circuit and a second amplification circuit, and the two coupling terminals include a first coupling terminal and a second coupling terminal; One end of the capacitance module in the first amplification circuit is connected to the first coupling terminal, and the other end of the capacitance module in the first amplification circuit is connected to the ground terminal; One end of the capacitance module in the second amplification circuit is connected to the second coupling terminal, and the other end of the capacitance module in the second amplification circuit is connected to the ground terminal; One end of the first linear inductance module in the first amplification circuit is connected to the first coupling terminal; One end of the first linear inductance module in the second amplification circuit is connected to the second coupling terminal.

4. The quantum circuit according to claim 3, wherein, The first amplification circuit and the second amplification circuit share the same second linear inductance module; One end of the second linear inductance module is connected to the other end of the first linear inductance module in the first amplification circuit and the other end of the first linear inductance module in the second amplification circuit.

5. The quantum circuit according to claim 3, wherein, The first amplification circuit and the second amplification circuit respectively include their own second linear inductance modules; The other end of the first linear inductance module in the first amplification circuit is connected to one end of the second linear inductance module in the first amplification circuit; The other end of the first linear inductance module in the second amplification circuit is connected to one end of the second linear inductance module in the second amplification circuit.

6. The quantum circuit according to any one of claims 1 to 5, wherein, The quantum circuit further includes a third linear inductance module and a current input terminal for inputting current to the third linear inductance module. The third linear inductance module is mutually inductively connected to the second linear inductance module, and the third linear inductance module is connected to the current input terminal.

7. The quantum circuit according to any one of claims 1 to 6, wherein, The capacitance module includes distributed capacitance.

8. The quantum circuit according to any one of claims 1 to 7, wherein, The amplification circuit is prepared by a planar process.

9. An amplification device, comprising an amplification circuit, a grounding end, and a coupling end, wherein the amplification circuit includes a capacitor module, a first linear inductor module, a second linear inductor module, and a Josephson junction; One end of the capacitor module is connected to the coupling end, and the other end of the capacitor module is connected to the grounding end; One end of the first linear inductor module is connected to the coupling end, the other end of the first linear inductor module is connected to one end of the second linear inductor module, and the other end of the second linear inductor module is connected to the grounding end; The Josephson junction is connected in parallel across both ends of the second linear inductor module.

10. A chip structure, comprising the quantum circuit according to any one of claims 1 to 8, or comprising the amplification device according to claim 9.

11. A method for measuring the state of a qubit, applied to a processor, wherein the processor is connected to the measurement output end in the quantum circuit according to any one of claims 1 to 8, and the measurement method includes: When a microwave signal is input to the measurement input end, obtaining a target voltage signal output from the measurement output end; Determining a target phase and a target amplitude according to the target voltage signal, and determining a target measurement point in a first coordinate space according to the target phase and the target amplitude; Determining the state of the qubit according to the belonging relationship between the target measurement point and a first sample point region or a second sample point region, wherein the first sample point region and the second sample point region are preset in the first coordinate space, and the first sample point region and the second sample point region are respectively used to indicate two different states of the qubit.

12. The measuring method according to claim 11, wherein, Before determining the state of the qubit according to the belonging relationship between the target measurement point and a first sample point region or a second sample point region, the measurement method further includes: Determining the signal frequency; Setting the state of the qubit to a first state, and in the first state, whenever a target microwave signal with the signal frequency is input to the measurement input end, obtaining a first sample voltage signal output from the measurement output end each time, determining a first sample measurement point corresponding to the first sample voltage signal in the first coordinate space, and obtaining the first sample point region according to a plurality of the first sample measurement points; Setting the state of the qubit to a second state, and in the second state, whenever a target microwave signal with the signal frequency is input to the measurement input end, obtaining a second sample voltage signal output from the measurement output end each time, determining a second sample measurement point corresponding to the second sample voltage signal in the first coordinate space, and obtaining the second sample point region according to a plurality of the second sample measurement points.

13. The measuring method according to claim 12, wherein, The determining the signal frequency includes: Obtaining curve data of the device frequency of the amplification circuit changing with the magnetic flux of the amplification circuit, wherein the curve data includes a first change curve corresponding to the first state and a second change curve corresponding to the second state, and the first change curve and the second change curve are located in the same second coordinate space; Obtain the target frequency corresponding to the intersection point between the first variation curve and the second variation curve; Determine the difference between the target frequency and a preset value as the signal frequency, or determine the signal frequency within the frequency range including the target frequency.

14. The measuring method according to any one of claims 11 to 13, wherein, The determining the target phase and the target amplitude according to the target voltage signal includes: Demodulate the target voltage signal to obtain a demodulated voltage signal; Sample the demodulated voltage signal to obtain a sampled voltage signal; Restore the sampled voltage signal to obtain a restored voltage signal; Determine the phase of the restored voltage signal as the target phase and determine the amplitude of the restored voltage signal as the target amplitude.

15. A measurement device for a quantum bit state, the measurement device being connected to the measurement output end in the quantum circuit according to any one of claims 1 to 8, the measurement device comprising: A signal acquisition module configured to acquire a target voltage signal output by the measurement output end when a microwave signal is input to the measurement input end; A signal processing module configured to determine a target phase and a target amplitude according to the target voltage signal, and determine a target measurement point in a first coordinate space according to the target phase and the target amplitude; A state determination module configured to determine the state of the quantum bit according to the attribution relationship between the target measurement point and a first sample point region or a second sample point region, the first sample point region and the second sample point region being preset in the first coordinate space, and the first sample point region and the second sample point region being respectively used to indicate two different states of the quantum bit.

16. An electronic device, comprising a memory and a processor, the memory storing a computer program, and the processor implementing the measurement method according to any one of claims 11 to 14 when executing the computer program.

17. A computer-readable storage medium storing a computer program, the computer program implementing the measurement method according to any one of claims 11 to 14 when executed by a processor.

18. A computer program product comprising a computer program, the computer program implementing the measurement method according to any one of claims 11 to 14 when executed by a processor.

Images