Rabis oscillation calibration method and device for quantum computing, medium and equipment

Abstract

The invention discloses a Rabian oscillation calibration method and device for quantum computing, a medium and equipment. The method comprises the following steps: receiving a trigger instruction, and then executing Rabis oscillation measurement to obtain measurement data; performing nonlinear fitting processing on the measurement data according to a preset fitting curve to obtain a calibration pi duration; and updating the current Pi duration by adopting the calibrated Pi duration, and compiling the quantum computing task which is not executed based on the current Pi duration. By applying the method, automatic calibration of the Pi duration of the Rabian oscillation can be realized, optimization fitting is automatically carried out, a new Pi duration calibration value is obtained without manual intervention, and the new Pi duration calibration value is automatically applied to a quantum computing task.

Description

Technical Field

[0001] The present invention relates to the field of quantum computer technology, and in particular to a Rabi oscillation calibration method, device, medium and equipment for quantum computing. Background Art

[0002] A quantum computer is a device that follows the laws of quantum mechanics to perform high-speed mathematical and logical operations, store and process quantum information. Quantum computing is a computing technology based on the principles of quantum mechanics. It uses the superposition and entanglement of quantum bits to quickly process large amounts of data and solve some problems that are difficult to solve with classical computing. Ion trap quantum computers are a technical route for large-scale quantum computers. Ions or charged atomic particles can be confined and suspended in free space using electromagnetic fields. Quantum bits are stored in the stable electronic state of each ion, and quantum information can be transmitted through the collective quantized motion of ions in a shared trap (through Coulomb force interactions). Lasers are used to induce coupling between quantum bit states (for single quantum bit operations) or coupling between internal quantum bit states and external motion states (for entanglement between quantum bits).

[0003] In the quantum gates of ion trap quantum computers, the Native gate set generally includes R gates. R gates include ,because Can be decomposed into Combination of: , so the Native gate set can also be defined as including .

[0004] Physically, the interaction between microwave field or laser field and ions will form Rabi oscillation. According to the principle of Rabi oscillation, the R-gate rotation of quantum bit can be realized as follows: the rotation angle θ is controlled by the duration of the action: the specific duration required for the rotation angle θ The formula can be Get, where It is called π-time (or pi-time, π duration), which is the Rabi oscillation phenomenon. All the state populations are transferred to state, that is, rotation angle π or realization The duration of the action required for the rotation. The Rabi oscillation measurement is performed on each ion to determine its corresponding , which is used as a basis for calculating the duration of the rotation operation on the ion. Summary of the invention

[0005] The object of the present invention is to provide a Rabi oscillation calibration method, device, medium and equipment for quantum computing, so as to automatically perform Rabi oscillation measurement and realize automatic calibration.

[0006] According to one aspect of the present invention, a Rabi oscillation calibration method for quantum computing is provided, comprising: performing Rabi oscillation measurement after receiving a trigger instruction to obtain measurement data; performing nonlinear fitting processing on the measurement data according to a preset fitting curve to obtain a calibration π duration; using the calibration π duration to update the current π duration, and compiling unexecuted quantum computing tasks based on the current π duration.

[0007] According to an embodiment of the present invention, performing Rabi oscillation measurement after receiving a trigger instruction to obtain measurement data includes: starting a Rabi oscillation measurement process after receiving the trigger instruction; and collecting a sample of the number of photons during the Rabi oscillation measurement process.

[0008] According to one embodiment of the present invention, the trigger instruction is a pre-execution calibration instruction, which is a trigger for automatically executing a Rabi oscillation π duration calibration instruction configured before each quantum computing task is executed; or, The trigger instruction is an on-demand calibration instruction, which is an instruction to automatically perform a Rabi oscillation π duration calibration after receiving a π duration calibration request, and to keep the obtained calibration π duration until the next π duration calibration occurs; or, The trigger instruction is a timing calibration instruction, which is a π-duration calibration instruction that is executed regularly according to a preset calibration time.

[0009] According to one embodiment of the present invention, after receiving an on-demand calibration instruction, or reaching a set calibration time in a timed calibration instruction mode: If a quantum computing task is currently running, wait for it to finish running, and then calibrate the duration of the Rabi oscillation π; If no quantum computing task is currently running, the Rabi oscillation π duration calibration is performed directly.

[0010] According to an embodiment of the present invention, performing nonlinear fitting processing on the measurement data according to a preset fitting curve includes: Obtain bright state and dark state data of multiple sets of measurement data; Obtaining the bright state probabilities of multiple groups of measurement data according to the bright state and dark state data; Set the target fitting curve The initial values ​​of the parameters, where A is the amplitude, d is the offset, f is the frequency, and φ is the initial phase; According to the target fitting curve and the initial value of the parameter, the Rabi frequency and the π duration are obtained by automatically performing nonlinear fitting on the bright state probability.

[0011] According to one embodiment of the present invention, the target fitting curve The initial values ​​of the parameters include: The difference between the maximum and minimum values ​​of multiple groups of bright state probabilities is used as the initial value of the amplitude A; The mean or median of multiple groups of bright state probabilities is used as the initial value of the bias d; Use 0 as the initial value of the initial phase φ; The initial value of the frequency f is given by automatic analysis using fast Fourier transform.

[0012] According to one embodiment of the present invention, compiling the unexecuted quantum computing task based on the current π duration includes: The uncompiled and unexecuted quantum computing tasks are compiled according to the current π duration to generate the target code; or, the compiled and unexecuted quantum computing tasks are recompiled according to the current π duration to generate the target code.

[0013] According to another aspect of the present invention, there is provided a device for Rabi oscillation calibration for quantum computing, comprising: A Rabi oscillation measurement unit is configured to perform Rabi oscillation measurement after receiving a trigger instruction to obtain measurement data; A fitting unit is configured to perform nonlinear fitting processing on the measurement data according to a preset fitting curve to obtain a calibration π duration; A compiling unit is configured to use the calibrated π duration to update the current π duration, and compile the unexecuted quantum computing tasks based on the current π duration.

[0014] According to another aspect of the present invention, a computer-readable storage medium storing a computer program is provided, wherein when the computer program is executed by a processor, the above-mentioned Rabi oscillation calibration method for quantum computing is implemented.

[0015] According to another aspect of the present invention, a computer device is provided, the computer device comprising: a processor; a memory storing a computer program, and when the computer program is executed by the processor, the Rabi oscillation calibration method for quantum computing as described above is implemented.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) The calibration automation is achieved through the Rabi oscillation calibration for quantum computing, which improves the automation level and is fully automated without human intervention.

[0017] (2) Based on the Rabi oscillation calibration method of the present invention, remote Rabi oscillation automatic calibration can be realized, which can reduce the environmental interference caused by manual Rabi oscillation measurement, extend the decoherence time, execute quantum computing tasks with longer running time, and obtain more accurate result data.

[0018] (3) By intelligently processing the subsequent Rabi oscillation measurement data and automatically optimizing the fitting without human intervention, a new π duration calibration value is obtained, and the new π duration calibration value is automatically applied to quantum computing tasks, thereby improving execution efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above objects and features of the present invention will become more apparent from the following description in conjunction with the accompanying drawings.

[0020] Figure 1 Shown is a flow chart of a Rabi oscillation calibration method for quantum computing according to an exemplary embodiment of the present invention.

[0021] Figure 2 Shown is a schematic diagram of a device for Rabi oscillation calibration for quantum computing according to an exemplary embodiment of the present invention.

[0022] Figure 3 Shown is a schematic diagram of a nonlinear fitting result based on Rabi oscillation measurement data according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0023] In a trapped ion quantum computer, the duration of the interaction between a microwave field or a laser field and the ions in the ion trap is controlled. The state vector is rotated around different axes by different angles θ to realize the quantum state evolution of the ion. Logic gate operation. Duration The calculation depends on the duration of π , and the duration of π Will drift due to environmental influences. After drift occurs, if you still use the previous Calculated by measured value conduct Logic gate operations can cause quantum computing tasks to be inaccurate, so they need to be re-measured. (Also known as calibration). Calibration is one of the important tasks in the calibration of ion trap quantum computers.

[0024] The determination is obtained by performing a nonlinear optimization fit on the photon number samples collected in the Rabi oscillation measurement. Measurement work and recalibration The work applied to subsequent quantum computing tasks is all performed manually: the Rabi oscillation measurement is manually redone to obtain the measurement data; the measurement data is post-processed, that is, the nonlinear optimization fitting of the Rabi oscillation measurement data is also called post-processing, by manually assigning initial values, and performing nonlinear optimization fitting on the measurement data to obtain the duration of π ; Manually modify the program code of the quantum computing task in subsequent quantum computing tasks or set and use the newly calibrated π duration through the task console interface Since the above measurement and calibration process requires manual intervention, the ion trap quantum computer cannot achieve long-term continuous operation and automatically execute the quantum computing tasks submitted by users.

[0025] The idea of ​​the present invention is to provide a solution for calibrating Rabi oscillations for quantum computing, to automatically perform Rabi oscillation measurement, post-processing of measurement data, and to recalibrate the Rabi oscillations. Applied to subsequent quantum computing tasks, the Rabi oscillation π duration calibration is automated. The Rabi oscillation calibration method for quantum computing realizes Calibration automation improves the automation level and is fully automated without human intervention. Therefore, remote Rabi oscillation automatic calibration can be achieved, which can reduce environmental interference caused by humans, extend the decoherence time, perform quantum computing tasks with longer running times, and obtain more accurate result data.

[0026] like Figure 1 As shown, a flow chart of a Rabi oscillation calibration method for quantum computing is provided, and the method comprises the following steps: Step S1: after receiving a trigger instruction, perform Rabi oscillation measurement to obtain measurement data; Step S2: Perform nonlinear fitting processing on the measured data according to a preset fitting curve to obtain a calibration time of π; Step S3: using the calibrated π duration to update the current π duration, and compiling unexecuted quantum computing tasks based on the current π duration.

[0027] In step S1, after receiving a trigger instruction, Rabi oscillation measurement is performed to obtain measurement data, including: after receiving the trigger instruction, starting the Rabi oscillation measurement process; collecting photon number samples during the Rabi oscillation measurement process.

[0028] The trigger instruction is a pre-execution calibration instruction, which is a trigger configured before the execution of each quantum computing task to automatically execute the Rabi oscillation π duration calibration instruction; or, the trigger instruction is an on-demand calibration instruction, which is an instruction to automatically execute a Rabi oscillation π duration calibration after receiving a π duration calibration request, and keep the obtained calibration π duration until the next π duration calibration occurs; or, the trigger instruction is a timed calibration instruction, which is a π duration calibration instruction that is executed regularly according to a preset calibration time.

[0029] For the pre-execution calibration instruction, it is necessary to calibrate the Rabi oscillation π duration before executing each quantum computing task. Calibration is performed according to the pre-execution calibration instruction, and the calibrated π duration affects each subsequent quantum computing task, but does not affect the quantum computing task that has been executed or is currently being executed.

[0030] For on-demand calibration instructions (On Demand calibration), a Rabi oscillation π duration calibration is required after the user's π duration calibration request. Subsequent quantum computing tasks all use this π duration calibration value until the next calibration occurs.

[0031] For the timing calibration instruction, the Rabi oscillation π duration needs to be calibrated according to the timing execution time set by the user. A variety of timing task time configuration rules such as fixed time, periodic time, and specified time point can be provided, so that users can flexibly set the calibration time as needed. According to the timing calibration instruction, if there is a quantum computing task currently running, the timing calibration will not affect the running quantum computing task.

[0032] After receiving the on-demand calibration command, or when the set calibration time is reached in the timed calibration mode, if there is a quantum computing task currently running, wait for it to end, and then perform the Rabi oscillation π duration calibration; if there is no quantum computing task currently running, directly perform the Rabi oscillation π duration calibration.

[0033] The trigger instruction can also be a combination of an on-demand calibration instruction, a timed calibration instruction, and a pre-execution calibration instruction, which is combined and set according to the quantum computing task, specifically including setting the Rabi oscillation π duration calibration mode, sending a π duration calibration request, or setting the calibration time in the timed calibration mode. The trigger instruction can be configured to trigger and schedule the execution of the Rabi oscillation measurement program, and these configuration information can be persistently stored in a file or database to avoid the loss of setting values ​​caused by power outages, downtime, and other events.

[0034] In step S1, after the Rabi oscillation measurement process is automatically started according to the trigger instruction, a sample of the number of photons in the Rabi oscillation measurement process is collected and persistently stored in a file or a database.

[0035] In the specific implementation, the Rabi oscillation measurement program trigger execution mechanism is configured, and the calibration request interface, system call, timer, task queue, different task priorities and saved calibration mode settings are used to automatically trigger and schedule the execution of the Rabi oscillation measurement program. After the Rabi oscillation measurement program is completed, the photon number samples collected during the Rabi oscillation measurement process are persistently stored in a file or database.

[0036] In step S2, for post-processing of the Rabi oscillation measurement data, nonlinear fitting processing is performed on the measurement data according to a preset fitting curve to obtain a calibration duration of π, which specifically includes the following steps: Step 201, determining bright and dark state data according to the photon number sample data, wherein if the photon number of the sample data is less than or equal to the bright and dark state determination threshold, it is determined as dark state data, otherwise it is determined as bright state data; For example, using the bright and dark state judgment threshold of 1, if ≤1 photon, it is a dark state, and if >1 photon, it is a bright state. Post-process each group of photon number sample data (generally 50 groups of data, each group of 300 photon number samples) to obtain the bright and dark state data (0 can be used to represent the dark state, and 1 can represent the bright state); Step 202 , obtaining a bright state probability ρ1 according to the bright and dark state data, wherein the bright and dark state data are statistically analyzed to obtain the percentage of the bright state in each group of bright and dark state data, that is, the bright state probability ρ1 .

[0037] Step 203, determine the target fitting curve as , where A is the amplitude, f is the frequency, φ is the initial phase, and d is the offset.

[0038] Step 204, setting the initial values ​​of the parameters of the target fitting curve, including the initial values ​​of the amplitude A, frequency f, initial phase φ, and offset d, where: The difference between the maximum and minimum values ​​in the bright state probability ρ1 data sequence is used as the initial value of the amplitude A; The initial value of frequency f is given by automatic analysis through fast Fourier transform (FFT); Set 0 as the initial value of the initial phase φ; The average value of the bright state probability ρ1 data sequence is used as the initial value of the offset d.

[0039] Step 205, perform automatic fitting, according to the target fitting curve, the set initial parameter values, and automatically optimize the nonlinear fitting bright state probability ρ1 to obtain the Rabi frequency and π duration .

[0040] Compared with the results obtained by manually assigning initial values ​​and then performing nonlinear optimization fitting using tools such as Mathematic or MatLab, the Rabi oscillation frequency (π duration) automatically calculated by post-processing the data in step S2 using an automated program 1 / 2 of the reciprocal of π), and then we can get the duration of π .

[0041] In the specific implementation process, the Rabi oscillation measurement data post-processing program trigger execution mechanism uses asynchronous messages, inter-process communication, system calls, task queues, different task priorities, etc. to automatically trigger and schedule the execution of the data post-processing program to process the generated measurement data, thus realizing the automatic processing of the measurement data. After the automatic data post-processing program runs, the calculated π duration calibration value Save it to the memory variable of the measurement and control system, and / or store it persistently in a file or database to avoid power outages, downtime, etc. causing the π time calibration value to be lost Lost, achieve π time calibration value storage.

[0042] In step S3, the duration calibration value π Once calibrated, all unexecuted quantum computing tasks must use the new π duration The target code must be regenerated. For quantum programs that have been compiled but not yet executed, they must also be recompiled to generate the target code.

[0043] For example, the translator reads the duration value of π from a persistent storage such as a file or database into a memory variable; or, during the translation process of the source program of the quantum computing task, the translator searches for the duration placeholder of π in the stage target code and replaces it with the newly calibrated duration value of π.

[0044] like Figure 2 As shown, a schematic diagram of a device for Rabi oscillation calibration for quantum computing is given, and the device includes: The Rabi oscillation measurement unit 21 is configured to perform Rabi oscillation measurement after receiving a trigger instruction to obtain measurement data; The fitting unit 22 is configured to perform nonlinear fitting processing on the measurement data according to a preset fitting curve to obtain a calibration duration of π; The compiling unit 23 is configured to use the calibrated π duration to update the current π duration, and compile the unexecuted quantum computing tasks based on the current π duration.

[0045] like Figure 3 As shown, the Rabi frequency (Rabi fre) of the final fitting result is 0.0623228 MHz, and the obtained π time (Rabi πtime) is 8.02274 ns, with an error of 5 decimal places, which meets the requirements of quantum computing tasks.

[0046] The Rabi oscillation calibration method proposed in the present invention can realize the automation of Rabi oscillation π duration calibration, intelligently process the subsequent Rabi oscillation measurement data, and automatically optimize the fitting without manual intervention to obtain a new π duration calibration value, and automatically apply the new π duration calibration value to quantum computing tasks. The ion trap quantum computer can automatically run based on the Rabi oscillation calibration method, and realize the quantum computing automation of the cloud platform by providing a cloud interface to receive and process quantum computing tasks submitted by users.

[0047] In addition, a computer-readable storage medium storing a computer program may also be provided according to an exemplary embodiment of the present invention. The computer-readable storage medium stores a computer program that, when executed by a processor, causes the processor to perform a Rabi oscillation calibration method for quantum computing according to an exemplary embodiment of the present invention. The computer-readable recording medium is any data storage device that can store data read out by a computer system. Examples of computer-readable recording media include: read-only memory, random access memory, read-only optical disk, magnetic tape, floppy disk, optical data storage device, and carrier wave (such as data transmission through the Internet via a wired or wireless transmission path).

[0048] In addition, a computing device may also be provided according to an exemplary embodiment of the present invention. The computing device includes a processor and a memory. The memory is used to store a computer program. The computer program is executed by the processor so that the processor executes the computer program of the Rabi oscillation calibration method for quantum computing according to an exemplary embodiment of the present invention.

[0049] It should be noted that the first, second, third, fourth, etc. in the above description are to distinguish features with the same name in the same or different embodiments, and are not quantitative limitations. And the present invention is not limited to the specific configurations and processes described above or shown in the figures. The above is only a specific embodiment of the present invention. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working process of the described system, device, module or module can refer to the corresponding process in the method embodiment without further description. It should be understood that the scope of protection of the present invention is not limited to this. Any technician familiar with the technical field can think of various equivalent modifications or substitutions within the technical scope disclosed by the present invention, and these modifications or substitutions should be covered within the scope of protection of the present invention.

Claims

1. A Rabi oscillation calibration method for quantum computing, characterized in that: include: After receiving the trigger command, the Rabi oscillation measurement is performed to obtain the measurement data; Perform nonlinear fitting processing on the measured data according to the preset fitting curve to obtain the calibration π time length; The calibrated π duration is used to update the current π duration, and unexecuted quantum computing tasks are compiled based on the current π duration.

2. The method according to claim 1, characterized in that The method of performing Rabi oscillation measurement after receiving the trigger instruction to obtain measurement data includes: After receiving the trigger instruction, starting the Rabi oscillation measurement process; Collecting photon count samples during Rabi oscillation measurement.

3. The method according to claim 1, characterized in that The trigger instruction is a pre-execution calibration instruction, which is a trigger for automatically executing a Rabi oscillation π duration calibration instruction configured before each quantum computing task is executed; or, The trigger instruction is an on-demand calibration instruction, which is an instruction to automatically perform a Rabi oscillation π duration calibration after receiving a π duration calibration request, and to keep the obtained calibration π duration until the next π duration calibration occurs; or, The trigger instruction is a timing calibration instruction, which is a π-duration calibration instruction that is executed regularly according to a preset calibration time.

4. The method according to claim 3, characterized in that After receiving an on-demand calibration command, or when the set calibration time is reached in the scheduled calibration command mode: If a quantum computing task is currently running, wait for it to finish running, and then calibrate the duration of the Rabi oscillation π; If no quantum computing task is currently running, the Rabi oscillation π duration calibration is performed directly.

5. The method according to claim 1, characterized in that The performing nonlinear fitting processing on the measurement data according to the preset fitting curve includes: Obtain bright state and dark state data of multiple sets of measurement data; Obtaining the bright state probabilities of multiple groups of measurement data according to the bright state and dark state data; Set the target fitting curve The initial values ​​of the parameters, where A is the amplitude, d is the offset, f is the frequency, and φ is the initial phase; According to the target fitting curve and the initial value of the parameter, the Rabi frequency and the π duration are obtained by automatically performing nonlinear fitting on the bright state probability.

6. The method according to claim 5, characterized in that The target fitting curve The initial values ​​of the parameters include: The difference between the maximum and minimum values ​​of multiple groups of bright state probabilities is used as the initial value of the amplitude A; The mean or median of multiple groups of bright state probabilities is used as the initial value of the offset d; Use 0 as the initial value of the initial phase φ; The initial value of the frequency f is given by automatic analysis using fast Fourier transform.

7. The method according to claim 1, characterized in that The unexecuted quantum computing tasks compiled based on the current π time length include: The uncompiled and unexecuted quantum computing tasks are compiled according to the current π duration to generate the target code; or, the compiled and unexecuted quantum computing tasks are recompiled according to the current π duration to generate the target code.

8. A device for calibrating Rabi oscillations for quantum computing, characterized in that: include: A Rabi oscillation measurement unit, configured to perform Rabi oscillation measurement after receiving a trigger instruction to obtain measurement data; A fitting unit is configured to perform nonlinear fitting processing on the measurement data according to a preset fitting curve to obtain a calibration π duration; A compiling unit is configured to use the calibrated π duration to update the current π duration, and compile the unexecuted quantum computing tasks based on the current π duration.

9. A computer-readable storage medium storing a computer program, wherein: When the computer program is executed by a processor, the Rabi oscillation calibration method for quantum computing according to any one of claims 1 to 7 is implemented.

10. A computing device comprising: processor; A memory storing a computer program, which, when executed by a processor, implements the Rabi oscillation calibration method for quantum computing as described in any one of claims 1 to 7.

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