Hardware implementation method of derivative removal adiabatic quantum gate technology

Abstract

The invention provides a hardware implementation method of a derivative removal adiabatic quantum gate technology. The method comprises the following steps: reading a discrete Gaussian waveform from a memory based on a first frequency control word register; calculating to obtain a DRAG corrected Gaussian waveform based on a weighting coefficient register, a correction formula and the discrete Gaussian waveform; generating a discrete sinusoidal waveform based on the second frequency control word register and the phase control word register, and multiplying the discrete sinusoidal waveform by the DRAG corrected Gaussian waveform to obtain a DRAG corrected Gaussian modulation sine wave; and controlling the amplitude of the DRAG-corrected Gaussian modulation sine wave based on the amplitude control word register. In the scheme, based on a plurality of registers and a theoretical mathematical formula, the Gaussian pulse of DRAG correction is realized in the programmable logic device, and the purpose of hardware acceleration of the DRAG technology is realized on the premise of ensuring the precision.

Description

Technical Field

[0001] The present invention relates to the field of quantum measurement and control technology, and in particular to a hardware implementation method of a derivative-removing adiabatic quantum gate technology. Background Art

[0002] Currently, in superconducting qubit measurement and control systems, Transmon qubits are a type of superconducting qubit widely used in quantum computing. When performing single-bit gate control on Transmon qubits, there will be phenomena such as AC Stark shift and qubit high-energy level transition, which will introduce single-bit gate phase error and single-bit gate |2> state leakage error, respectively, seriously affecting the fidelity of single-bit gates. (1) Phase error: The microwave pulse used to control the qubit will interact with the qubit energy level, that is, the AC Stark effect, causing the qubit energy level frequency to shift, thereby causing phase error. (2) |2> state leakage error: Transmon qubits usually have weak anharmonicity, that is, the energy level frequency interval (E |1> -E |0> ) / h and energy level frequency interval (E |2> -E |1> ) / h is very close. Since the frequency of the microwave pulse has a certain bandwidth, this bandwidth will become wider as the microwave pulse shortens. When the required gate time is very short, the frequency of the microwave pulse will simultaneously cover the frequency (E |1> -E |0> ) / h, frequency (E |2> -E |1> ) / h, frequency (E |2> -E |0> ) / 2h (two-photon excitation frequency), which introduces non-negligible |2> state excitation errors, leading to leakage errors. Of these two errors, leakage errors account for a larger proportion and have a more serious impact on the fidelity of single-bit gates.

[0003] DRAG (Derivative Removal by Adiabatic Gate) technology is a technique that (1) regulates and controls the microwave signal frequency and the frequency (E |1> -E |0> ) / h to suppress phase errors. (2) A component orthogonal to the control signal is added to the control signal to suppress leakage errors. We further describe the principle of DRAG from the perspective of Hamiltonian. The control microwave signal and system Hamiltonian used in DRAG are shown as follows:

[0004]

[0005]

[0006] where Ωx ,Ω y is the amplitude envelope of the original control signal and the added orthogonal component. In experiments, Gaussian envelope is generally used. d is the angular frequency of the control signal, α1 is the anharmonic angular frequency of the quantum bit (α1=2π(E |2> +E |0> -2E |1> ) / h), Δ1=2π(E |1> -E |0> ) / h-ω d ,Δ2=2π(E |2> -E |0> ) / h-ω d , λ is a constant less than 1, is the imaginary number symbol, is the reduced Planck constant. The second term in the Hamiltonian is the two-photon excitation |0>→|2>, which produces leakage error, but it is very weak and can be ignored. The fourth term is the AC Stark phase error, which can be reduced to zero by adjusting Δ1. This term is generally weak and can be ignored experimentally. The fifth term contains the |1>→|2> excitation, which produces leakage error. This can be reduced to zero by adjusting the amplitude of the orthogonal component, thereby suppressing leakage.

[0007] In the prior art, the first approach to implementing DRAG technology is to implement an RC differential circuit through hardware. However, generating derivative components by changing the hardware circuit is highly dependent on hardware performance, and even slight differences can have a significant impact. Furthermore, adjustable resistors and capacitors also have issues with the precision of the electronic components, which can lead to control accuracy issues for this method, especially in the case of multi-bit coupling. Another approach is to allow users to generate custom pulses on the host computer and independently explore the suppression of quantum bit energy level leakage. This method offers a certain degree of convenience, but requires users to have a certain familiarity with mathematical formulas. Furthermore, the control pulse of a quantum logic gate is typically a splicing of multiple combined pulses. If the control pulse of a quantum logic gate is too long, then the transmission of the custom waveform from the host computer to the superconducting quantum measurement and control system will take a considerable amount of time, resulting in low experimental efficiency and hindering the rapid manipulation of the quantum logic gate, thereby affecting computational efficiency. Summary of the Invention

[0008] In view of this, an embodiment of the present invention provides a hardware implementation method of a derivative removal adiabatic quantum gate technology, so as to achieve the purpose of hardware acceleration of the DRAG technology while ensuring accuracy.

[0009] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0010] An embodiment of the present invention discloses a hardware implementation method of a derivative-removed adiabatic quantum gate technology, which is applied to a programmable logic device in a superconducting quantum measurement and control system. The programmable logic device includes: a memory, a first frequency control word register, a weighting coefficient register, a second frequency control word register, a phase control word register, and an amplitude control word register. The method includes:

[0011] When receiving a trigger signal input by a user, reading a pre-stored normalized discrete Gaussian waveform from the memory based on the first frequency control word stored in the first frequency control word register;

[0012] Calculating a DRAG-corrected Gaussian waveform based on the weighting coefficient stored in the weighting coefficient register, a preset DRAG correction formula, and the discrete Gaussian waveform;

[0013] generating a discrete sinusoidal waveform based on the second frequency control word stored in the second frequency control word register and the phase control word stored in the phase control word register;

[0014] multiplying the discrete sine waveform by the DRAG-modified Gaussian waveform to obtain a DRAG-modified Gaussian modulated sine wave;

[0015] Based on the amplitude control word stored in the amplitude control word register, the amplitude of the DRAG-modulated Gaussian modulated sine wave is controlled to obtain the amplitude-controlled DRAG-modulated Gaussian modulated sine wave.

[0016] Optionally, the method further includes:

[0017] receiving configuration parameters for the first frequency control word register, the weighting coefficient register, the second frequency control word register, the phase control word register, and the amplitude control word register sent by a host computer; the configuration parameters are input by a user through the host computer;

[0018] Based on the configuration parameters, the values ​​in the first frequency control word register, the weighting coefficient register, the second frequency control word register, the phase control word register, and the amplitude control word register are configured.

[0019] Optionally, the calculating a DRAG-corrected Gaussian waveform based on the weighting coefficient stored in the weighting coefficient register, a preset DRAG correction formula, and the discrete Gaussian waveform includes:

[0020] Calculating the waveform length of the discrete Gaussian waveform;

[0021] Performing signed number multiplication and signed number addition based on the weighting coefficient stored in the weighting coefficient register, the waveform length, a preset DRAG correction formula, and the discrete Gaussian waveform to obtain a DRAG-corrected Gaussian waveform;

[0022] The DRAG correction formula includes:

[0023]

[0024] in, is the Gaussian waveform modified by DRAG, is the discrete Gaussian waveform, D is the weighting coefficient, L is the waveform length, , , , a is the user preset value.

[0025] Optionally, multiplying the discrete sine waveform by the DRAG-modified Gaussian waveform to obtain a DRAG-modulated Gaussian modulated sine wave includes:

[0026] Performing time alignment on the discrete sine waveform and the DRAG-corrected Gaussian waveform;

[0027] The discrete sine waveform after time alignment is multiplied by the DRAG-modified Gaussian waveform to obtain a DRAG-modulated Gaussian modulated sine wave.

[0028] Optionally, controlling the amplitude of the DRAG-modulated Gaussian modulated sine wave based on the amplitude control word stored in the amplitude control word register to obtain the DRAG-modulated Gaussian modulated sine wave after amplitude control includes:

[0029] Each sampling point data in the DRAG-corrected Gaussian modulated sine wave is multiplied by the amplitude control word stored in the amplitude control word register to obtain the DRAG-corrected Gaussian modulated sine wave after amplitude control.

[0030] Optionally, after obtaining the amplitude-controlled DRAG-modulated Gaussian modulated sine wave, the method further includes:

[0031] The DRAG-modulated Gaussian modulated sine wave with amplitude control is output to a digital-to-analog converter in the superconducting quantum measurement and control system, so that the digital-to-analog converter converts the DRAG-modulated Gaussian modulated sine wave with amplitude control into an analog signal.

[0032] Optionally, pre-storing the normalized discrete Gaussian waveform includes:

[0033] Generate discrete Gaussian waveform based on the principle of direct digital frequency synthesis;

[0034] intercepting the discrete Gaussian waveform to obtain a discrete Gaussian waveform of a preset length;

[0035] Normalizing the discrete Gaussian waveform of the preset length to obtain a normalized discrete Gaussian waveform;

[0036] The normalized discrete Gaussian waveform is stored in the memory.

[0037] Optionally, normalizing the discrete Gaussian waveform of the preset length to obtain a normalized discrete Gaussian waveform includes:

[0038] Calculating the step height generated by intercepting the discrete Gaussian waveform;

[0039] After subtracting the step height from the discrete Gaussian waveform of the preset length, the discrete Gaussian waveform of the preset length is normalized to obtain a normalized discrete Gaussian waveform.

[0040] Optionally, when receiving a trigger signal input by a user, reading a pre-stored normalized discrete Gaussian waveform from the memory based on the first frequency control word stored in the first frequency control word register includes:

[0041] When receiving a trigger signal input by a user, the programmable logic device reads out the data pre-stored in the memory in sequence according to the first frequency control word under the system clock, and forms a normalized discrete Gaussian waveform.

[0042] Optionally, the programmable logic device includes any one of a field programmable gate array, a complex programmable logic device and an erasable programmable logic device, and the memory includes a ROM memory.

[0043] Based on the hardware implementation method of the derivative removal adiabatic quantum gate technology provided by the above-mentioned embodiment of the present invention, when a trigger signal input by the user is received, based on the first frequency control word stored in the first frequency control word register, a pre-stored normalized discrete Gaussian waveform is read from the memory; based on the weighting coefficient stored in the weighting coefficient register, a preset DRAG correction formula and the discrete Gaussian waveform, a DRAG-corrected Gaussian waveform is calculated; based on the second frequency control word stored in the second frequency control word register and the phase control word stored in the phase control word register, a discrete sinusoidal waveform is generated; the discrete sinusoidal waveform is multiplied by the DRAG-corrected Gaussian waveform to obtain a DRAG-corrected Gaussian modulated sine wave; based on the amplitude control word stored in the amplitude control word register, the amplitude of the DRAG-corrected Gaussian modulated sine wave is controlled to obtain the DRAG-corrected Gaussian modulated sine wave after amplitude control. In this solution, based on multiple registers and theoretical mathematical formulas, Gaussian pulses for DRAG correction are implemented inside a programmable logic device. This avoids the inaccurate DRAG correction problem caused by RC differential circuits, as well as the time-consuming transmission process of the host computer generating a custom DRAG correction waveform to the superconducting quantum measurement and control system. This achieves the goal of hardware acceleration of DRAG technology while ensuring accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0045] Figure 1 This is a structural diagram of a superconducting quantum measurement and control system disclosed in an embodiment of the present invention;

[0046] Figure 2 A structural diagram of a programmable logic device disclosed in an embodiment of the present invention;

[0047] Figure 3 A flowchart of a hardware implementation method of a derivative removal adiabatic quantum gate technology disclosed in an embodiment of the present invention;

[0048] Figure 4 A schematic diagram of a step generated by intercepting a discrete Gaussian waveform disclosed in an embodiment of the present invention;

[0049] Figure 5 A schematic diagram of a related waveform disclosed in an embodiment of the present invention. DETAILED DESCRIPTION

[0050] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0051] In this application, the terms "comprises," "comprising," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0052] First, it's important to note that DRAG (Derivative Removal by Adiabatic Gate) is a complex method for controlling Transmon qubits. Its primary goal is to suppress Stark phase errors and |2> state leakage errors, thereby improving the fidelity of single-bit gate operations. The core idea of ​​DRAG is to add a component orthogonal to the original control pulse. This component has a frequency equal to that of the original control signal, but its amplitude is related to the time derivative of the original control signal's amplitude waveform envelope and the anharmonicity of the qubit. The amplitude envelope of the gate pulse used to control the qubit is typically Gaussian. This Gaussian envelope concentrates energy on the main frequency component, thereby suppressing spurious components at other frequencies. By adding an appropriate control component orthogonal to the original control signal, it effectively cancels out |2> state excitations introduced by imperfect control pulse bandwidth, thereby suppressing the |2> state leakage errors discussed in the background.

[0053] As can be seen from the background technology, there are two methods for implementing DRAG technology in the prior art:

[0054] The first method is to implement an RC differential circuit through hardware. Considering Transmon qubits, superconducting qubit measurement and control systems typically use microwave signals to drive the qubits for quantum state manipulation and readout. In this process, the pulse shaping of the microwave signal is crucial to the accuracy of quantum gate operations and the coherence time of the qubit.

[0055] As a bridge between classical electronic control systems and quantum bits, the design of the printed circuit board (PCB) in classical circuits plays a decisive role in the pulse shaping of microwave signals. A perfect PCB design not only ensures the integrity of the microwave signal, but also effectively suppresses parasitic effects and optimizes the pulse waveform of the microwave signal, thereby improving the controllability and computational accuracy of quantum computing. The microwave signals used in superconducting quantum computing are typically used to implement quantum logic gate operations (such as X, Y, and Z gates) or measure and read quantum states. Microwave signals are typically generated using IQ modulation technology and transmitted through classical circuit boards and transmission cables and coupled to the quantum chip in a low-temperature superconducting environment. Ideally, the microwave signal used to drive the quantum bit should meet the following characteristics:

[0056] 1) Avoid steep rising and falling edges to reduce unexpected excitation and spectrum leakage;

[0057] 2) Accurate and stable waveform amplitude and phase;

[0058] 3) Low noise and low waveform distortion to reduce unnecessary parasitic excitations and improve the coherence time of quantum bits.

[0059] DRAG technology involves adding a first-order derivative component to the pulse shape, which can be implemented using a differential circuit on a printed circuit board (PCB). An RC differential circuit is used to generate the derivative component of the microwave signal. Parameter tuning is achieved through adjustable resistors and capacitors to optimize the accuracy of quantum gate operations. Low-pass filters, such as Butterworth or Chebyshev filters, are also used to smooth the pulse edges, achieving pulse shaping of the microwave signal and reducing spectral leakage. Furthermore, the use of low-temperature stable materials, such as Rogers RT / duroid, in the design and production of the PCB can reduce the impact of temperature drift on pulse accuracy.

[0060] Another approach allows users to generate custom pulses on the host computer, exploring the suppression of qubit |2> state leakage errors to implement DARG pulse shaping. This custom waveform is transmitted to the superconducting qubit measurement and control system. After digital-to-analog conversion (DAC) and IQ mixing, a microwave signal in the 3-8 GHz range required for superconducting quantum computing is generated and delivered to the qubit.

[0061] In summary, the first existing approach to implementing DRAG technology is through hardware implementation using RC (resistance-capacitance) differential circuits. However, generating derivative components by modifying the hardware circuitry is highly dependent on hardware performance; even slight variations can have significant impacts. Furthermore, adjustable resistors and capacitors also present challenges with electronic component precision, which can lead to control accuracy issues, particularly in the presence of multi-bit coupling. Another approach allows users to generate custom pulses on a host computer, allowing them to independently explore the suppression of quantum bit |2> state leakage errors. This approach offers a certain degree of convenience but requires a certain level of familiarity with mathematical formulas. Furthermore, the control pulses of quantum logic gates are typically a concatenation of multiple combined pulses. If the control pulses are too long, transmitting the custom waveforms from the host computer to the superconducting quantum measurement and control system takes a significant amount of time, resulting in low experimental efficiency and hindering the rapid control of quantum logic gates, thus affecting computational efficiency.

[0062] Therefore, an embodiment of the present invention discloses a hardware implementation method of derivative-removed adiabatic quantum gate technology. In this solution, based on multiple registers and theoretical mathematical formulas, DRAG-corrected Gaussian pulses are implemented inside a programmable logic device, avoiding the problem of inaccurate DRAG correction accuracy achieved by an RC differential circuit, and avoiding the time-consuming transmission process of the host computer generating a custom DRAG correction waveform to the superconducting quantum measurement and control system, thereby achieving the purpose of hardware acceleration of DRAG technology while ensuring accuracy.

[0063] like Figure 1 , which is a structural diagram of a superconducting quantum measurement and control system disclosed in an embodiment of the present invention, the superconducting quantum measurement and control system includes: a programmable logic device 1, a digital-to-analog converter 2 and a quantum analyzer 3.

[0064] Among them, the programmable logic device 1 is connected to the host computer through a switch, the programmable logic device 1 is connected to the digital-to-analog converter 2, the digital-to-analog converter 2 is connected to the quantum chip, the quantum analyzer 3 is connected to the quantum chip, and the quantum analyzer 3 is connected to the host computer through a switch.

[0065] like Figure 2 FIG. 1 is a block diagram of a programmable logic device 1 according to an embodiment of the present invention. The programmable logic device 1 is internally configured with a memory 11 and a plurality of registers R1 to R5.

[0066] The memory 11 stores a normalized discrete Gaussian waveform of a certain length. The registers include: a first frequency control word register R1, a weighting coefficient register R2, a second frequency control word register R3, a phase control word register R4, and an amplitude control word register R5.

[0067] The values ​​in the first frequency control word register R1, weighting coefficient register R2, second frequency control word register R3, phase control word register R4, and amplitude control word register R5 (a total of 12 bytes) are configured by the user through the host computer in the initial state.

[0068] In this application, the specific hardware type of the programmable logic device 1 is not limited, and the type of the memory 11 in the programmable logic device 1 is also not limited. For example, the programmable logic device 1 can be a field programmable gate array (FPGA), a complex programmable logic device (CPLD), an erasable programmable logic device (EPLD), etc.

[0069] It should be noted that the functions implemented by the digital-to-analog converter 2 and the quantum analyzer 3 are all existing technologies, and the focus of this application is to configure multiple registers in the programmable logic device 1, thereby implementing DRAG technology inside the programmable logic device 1 based on multiple registers and theoretical mathematical formulas, without changing the programmable logic device 1's original function of generating arbitrary waveforms.

[0070] like Figure 3 FIG. 1 is a flowchart of a hardware implementation method of a derivative removal adiabatic quantum gate technology disclosed in an embodiment of the present invention. The method is applied to a programmable logic device 1 in a superconducting quantum measurement and control system, and includes the following steps:

[0071] Step S101: when a trigger signal input by a user is received, a pre-stored normalized discrete Gaussian waveform is read from a memory based on a first frequency control word stored in a first frequency control word register.

[0072] In step S101 , a trigger signal is input by a user through a host computer and transmitted to the programmable logic device 1 via a switch.

[0073] When a trigger signal arrives, programmable logic device 1, under the system clock, sequentially reads data stored in memory 11 (e.g., ROM memory) according to a first frequency control word, and constructs a discrete Gaussian waveform. The first frequency control word controls the frequency of the extracted discrete Gaussian waveform.

[0074] It is understandable that the discrete Gaussian waveform in the memory is pre-generated and stored in the memory after normalization. The specific generation and storage process is as follows:

[0075] Specifically, a discrete Gaussian waveform is generated based on the principle of direct digital synthesis (DDS), the discrete Gaussian waveform is truncated to obtain a discrete Gaussian waveform of a preset length, the discrete Gaussian waveform of the preset length is normalized to obtain a normalized discrete Gaussian waveform, and the normalized discrete Gaussian waveform is stored as discrete Gaussian waveform data in the memory 11 of the programmable logic device 1. The discrete Gaussian waveform data has a depth of 16,384 and a vertical resolution of 16 bits.

[0076] The normalization process is as follows: calculating the step height generated by intercepting the discrete Gaussian waveform; subtracting the step height from the discrete Gaussian waveform of a preset length, and then normalizing the discrete Gaussian waveform of the preset length to obtain a normalized discrete Gaussian waveform.

[0077] Normalizing the discrete Gaussian waveform of the preset length refers to adjusting the value range (ie, amplitude) of the discrete Gaussian waveform of the preset length to a specific interval (usually [0, 1]).

[0078] Before step S101, the user needs to configure the values ​​stored in the first frequency control word register R1, the weight coefficient register R2, the second frequency control word register R3, the phase control word register R4, and the amplitude control word register R5 through the host computer. The specific process is as follows:

[0079] Receive the configuration parameters for the first frequency control word register R1, the weighting coefficient register R2, the second frequency control word register R3, the phase control word register R4 and the amplitude control word register R5 sent by the host computer; based on the configuration parameters, configure the values ​​in the first frequency control word register R1, the weighting coefficient register R2, the second frequency control word register R3, the phase control word register R4 and the amplitude control word register R5.

[0080] The configuration parameters are input by the user through the host computer, and include specific values ​​to be stored in the first frequency control word register R1, weighting coefficient register R2, second frequency control word register R3, phase control word register R4 and amplitude control word register R5.

[0081] Step S102: Calculate and obtain a DRAG-corrected Gaussian waveform based on the weighting coefficient stored in the weighting coefficient register R2, the first frequency control word stored in the first frequency control word register R1, a preset DRAG correction formula, and a discrete Gaussian waveform.

[0082] In step S102, the derivation process of the DRAG correction formula is as follows:

[0083] Assume that the original Gaussian waveform is generated by the following formula:

[0084] (1)

[0085] in is the peak amplitude, which is a constant. Let's assume =1, is the variance. In practical applications, the waveform signal is usually discretized to obtain a discrete Gaussian waveform. , and then converted into analog signals through the digital-to-analog converter DAC. In the superconducting quantum measurement and control system, assuming that the length of the Gaussian waveform sample point corrected by DRAG is L (i.e., the waveform length), a is the ratio of the waveform length L to the variance, then the variance , a is the user preset value 5, which is preset by the user based on experience, However, since the truncation of discrete data will cause the discrete waveform to have steps, it is necessary to subtract the steps caused by the truncation so that the value at the edge is 0.

[0086] like Figure 4 FIG. 1 is a schematic diagram of a step formed by intercepting a discrete Gaussian waveform disclosed in an embodiment of the present invention.

[0087] It should be noted that a step refers to when discrete data of a preset length is cut from a discrete Gaussian waveform, the value at the cutoff point (ie, the waveform amplitude at the cutoff point) is not 0, that is, a discontinuous mutation occurs.

[0088] Subtracting the steps caused by truncation means calculating the average value or other statistical value of the truncation waveform at the start and end points (i.e., the edges) as the step height. For a Gaussian waveform, the amplitude at the start and end points are the same, and the average value is equivalent to the amplitude at the start or end point. This step height is then subtracted from the entire waveform data, thereby adjusting the waveform value at the edge to 0. This can avoid discontinuities when truncation occurs and facilitate subsequent processing.

[0089] The value of 0 at the edge means that the amplitude of the waveform is 0 at the start point and the end point of the interception of the waveform.

[0090] Let y0 represent the step height, and the calculation formula of y0 is as follows:

[0091] (2)

[0092] Then the step height is subtracted and the normalized discrete Gaussian waveform is :

[0093] (3)

[0094] in , assuming the DAC sampling rate is 1Gsa / s, it means one sample point is 1ns.

[0095] Then the pulse after DRAG correction with the derivative component added becomes:

[0096] (4)

[0097] Among them is Anharmonic coefficient.

[0098] Combining formulas (3) and (4), we get:

[0099] (5)

[0100] in ,make , represents the discrete Gaussian waveform after interception and normalization (ie, the discrete Gaussian waveform extracted from the memory 11). Finally, the Gaussian waveform modified by DRAG is abstracted as (represents a truncated but unnormalized discrete Gaussian waveform), a function with L and D as variables (i.e., the DRAG correction formula):

[0101] (6)

[0102] In the specific implementation process of step S102 , the waveform length L of the discrete Gaussian waveform is first calculated, that is, the preset length used when intercepting the continuous discrete Gaussian waveform.

[0103] Then, based on the weighting coefficient stored in the weighting coefficient register R2, the waveform length, the preset DRAG correction formula and the discrete Gaussian waveform, the signed number multiplication and signed number addition are performed to obtain the DRAG corrected Gaussian waveform (that is, each discrete waveform data point is obtained). ).

[0104] It should be noted that due to the preset DRAG correction formula, that is, It is signed data, determined by the value of n If n is greater than or equal to ,but The sign is positive and its value is ; If n is less than , The sign is negative and its value is ,but Need to be converted to two's complement form.

[0105] In this way, the programmable logic device 1 can generate a DRAG-modified Gaussian waveform with adjustable frequency and length through the first frequency control word register R1, a pre-stored discrete Gaussian waveform of a certain length, and the weighting coefficient register R2.

[0106] When D=0, it indicates a Gaussian waveform that has not been DRAG-corrected. The user can change the DRAG correction coefficient by adjusting the value of the weighting coefficient register R2 on the host computer.

[0107] Step S103: Generate a discrete sine waveform based on the second frequency control word stored in the second frequency control word register R3 and the phase control word stored in the phase control word register R4.

[0108] In step S103, the second frequency control word is used to control the frequency of the sinusoidal waveform, and the phase control word is used to control the phase of the sinusoidal waveform, so as to achieve the purpose of generating a discrete sinusoidal waveform with controllable frequency and phase.

[0109] Step S104: multiplying the discrete sine waveform with the DRAG-modified Gaussian waveform to obtain a DRAG-modulated Gaussian modulated sine wave.

[0110] It should be noted that, generally speaking, in superconducting quantum measurement and control systems, Gaussian modulated sine waves are used to drive quantum logic gates, such as the I gate, X gate, Y gate, and Z gate in the Clifford gate. Therefore, it is necessary to generate a DRAG-corrected Gaussian modulated sine wave based on the DRAG-corrected Gaussian waveform for subsequent use in driving quantum logic gates.

[0111] The principle of generating a Gaussian modulated sine wave is as follows: a discrete Gaussian waveform is multiplied point by point with a discrete sine waveform data to obtain a discrete Gaussian modulated sine wave.

[0112] Based on the above Gaussian modulated sine wave generation principle, the discrete sine waveform and the DRAG modified Gaussian waveform are multiplied point by point under the clock cycle of the timing alignment to obtain the discrete and DRAG modified Gaussian modulated sine wave. .

[0113] Specifically, the discrete sine waveform and the DRAG-modified Gaussian waveform are time-aligned; the time-aligned discrete sine waveform and the DRAG-modified Gaussian waveform are multiplied to obtain the DRAG-modulated Gaussian modulated sine wave.

[0114] Step S105: Based on the amplitude control word stored in the amplitude control word register R5, the amplitude of the DRAG-modulated Gaussian modulated sine wave is controlled to obtain the DRAG-modulated Gaussian modulated sine wave after amplitude control.

[0115] In the specific implementation process of step S105, the amplitude control word stored in the amplitude control word register R5 is multiplied by each sampling point data in the DRAG-corrected Gaussian modulated sine wave to control the amplitude of the DRAG-corrected Gaussian modulated sine wave and obtain the amplitude-controlled DRAG-corrected Gaussian modulated sine wave.

[0116] In one embodiment, after obtaining the amplitude-controlled DRAG-modulated Gaussian modulated sine wave, the method further includes:

[0117] The DRAG-corrected Gaussian modulated sine wave with amplitude control is output to the digital-to-analog converter 2 in the superconducting quantum measurement and control system, so that the digital-to-analog converter 2 converts the DRAG-corrected Gaussian modulated sine wave with amplitude control into an analog signal, so that the superconducting quantum measurement and control system can perform subsequent measurement and control processes.

[0118] like Figure 5 , which is a schematic diagram of a related waveform disclosed in an embodiment of the present invention.

[0119] The figure shows a comparison of three different waveforms, with time on the horizontal axis and amplitude on the vertical axis. The three waveforms are a Gaussian waveform (green line), a standard Gaussian-modulated sine wave (blue line), and a DRAG-modulated Gaussian-modulated sine wave (yellow line). The figure clearly illustrates the characteristics of these three waveforms. The Gaussian waveform provides excellent time-domain centralization, the standard Gaussian-modulated sine wave combines frequency characteristics with time-domain centralization, and the DRAG-modulated Gaussian-modulated sine wave reduces operational errors in quantum computing by optimizing the pulse shape. DRAG technology is crucial for improving the accuracy and reliability of quantum computing.

[0120] Based on the hardware implementation method of the derivative removal adiabatic quantum gate technology disclosed in the above-mentioned embodiment of the present invention, in this solution, based on multiple registers and theoretical mathematical formulas, a DRAG-corrected Gaussian pulse is implemented inside the programmable logic device 1, avoiding the problem of inaccurate DRAG correction accuracy achieved by the RC differential circuit, and avoiding the time-consuming transmission process of the host computer generating a custom DRAG correction waveform to the superconducting quantum measurement and control system, thereby achieving the purpose of hardware acceleration of DRAG technology while ensuring accuracy.

[0121] Each embodiment in this specification is described in a progressive manner. The same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple. For relevant parts, refer to the partial description of the method embodiment. The system and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. A person of ordinary skill in the art can understand and implement it without expending creative work.

[0122] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the components and steps of each example according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0123] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A hardware implementation method of a derivative removal adiabatic quantum gate technology, characterized in that: A programmable logic device used in a superconducting quantum measurement and control system, wherein the programmable logic device includes: a memory, a first frequency control word register, a weighting coefficient register, a second frequency control word register, a phase control word register, and an amplitude control word register, and the method includes: When receiving a trigger signal input by a user, reading a pre-stored normalized discrete Gaussian waveform from the memory based on the first frequency control word stored in the first frequency control word register; Calculating a DRAG-corrected Gaussian waveform based on the weighting coefficient stored in the weighting coefficient register, a preset DRAG correction formula, and the discrete Gaussian waveform; generating a discrete sinusoidal waveform based on the second frequency control word stored in the second frequency control word register and the phase control word stored in the phase control word register; multiplying the discrete sine waveform by the DRAG-modified Gaussian waveform to obtain a DRAG-modified Gaussian modulated sine wave; Based on the amplitude control word stored in the amplitude control word register, the amplitude of the DRAG-modulated Gaussian modulated sine wave is controlled to obtain the amplitude-controlled DRAG-modulated Gaussian modulated sine wave.

2. The method according to claim 1, characterized in that The method further comprises: receiving configuration parameters for the first frequency control word register, the weighting coefficient register, the second frequency control word register, the phase control word register, and the amplitude control word register sent by a host computer; the configuration parameters are input by a user through the host computer; Based on the configuration parameters, the values ​​in the first frequency control word register, the weighting coefficient register, the second frequency control word register, the phase control word register, and the amplitude control word register are configured.

3. The method according to claim 1, characterized in that The step of calculating a DRAG-corrected Gaussian waveform based on the weighting coefficient stored in the weighting coefficient register, a preset DRAG correction formula, and the discrete Gaussian waveform includes: Calculating the waveform length of the discrete Gaussian waveform; Performing signed number multiplication and signed number addition based on the weighting coefficient stored in the weighting coefficient register, the waveform length, a preset DRAG correction formula, and the discrete Gaussian waveform to obtain a DRAG-corrected Gaussian waveform; The DRAG correction formula includes: in, is the Gaussian waveform modified by DRAG, is the discrete Gaussian waveform, D is the weighting coefficient, L is the waveform length, , , , a is the user preset value.

4. The method according to claim 1, wherein The multiplying the discrete sine waveform by the DRAG-modified Gaussian waveform to obtain a DRAG-modulated Gaussian modulated sine wave comprises: Performing time alignment on the discrete sine waveform and the DRAG-corrected Gaussian waveform; The discrete sine waveform after time alignment is multiplied by the DRAG-modified Gaussian waveform to obtain a DRAG-modulated Gaussian modulated sine wave.

5. The method according to claim 1, wherein The step of controlling the amplitude of the DRAG-modulated Gaussian modulated sine wave based on the amplitude control word stored in the amplitude control word register to obtain the amplitude-controlled DRAG-modulated Gaussian modulated sine wave comprises: Each sampling point data in the DRAG-corrected Gaussian modulated sine wave is multiplied by the amplitude control word stored in the amplitude control word register to obtain the DRAG-corrected Gaussian modulated sine wave after amplitude control.

6. The method according to claim 1, characterized in that After obtaining the amplitude-controlled DRAG-modulated Gaussian modulated sine wave, the method further includes: The DRAG-modulated Gaussian modulated sine wave with amplitude control is output to a digital-to-analog converter in the superconducting quantum measurement and control system, so that the digital-to-analog converter converts the DRAG-modulated Gaussian modulated sine wave with amplitude control into an analog signal.

7. The method according to claim 1, characterized in that Pre-storing the normalized discrete Gaussian waveform includes: Generate discrete Gaussian waveform based on the principle of direct digital frequency synthesis; intercepting the discrete Gaussian waveform to obtain a discrete Gaussian waveform of a preset length; Normalizing the discrete Gaussian waveform of the preset length to obtain a normalized discrete Gaussian waveform; The normalized discrete Gaussian waveform is stored in the memory.

8. The method according to claim 7, characterized in that The normalizing process is performed on the discrete Gaussian waveform of the preset length to obtain a normalized discrete Gaussian waveform, comprising: Calculating the step height generated by intercepting the discrete Gaussian waveform; After subtracting the step height from the discrete Gaussian waveform of the preset length, the discrete Gaussian waveform of the preset length is normalized to obtain a normalized discrete Gaussian waveform.

9. The method according to claim 1, characterized in that The step of reading a pre-stored normalized discrete Gaussian waveform from the memory based on the first frequency control word stored in the first frequency control word register upon receiving a trigger signal input by the user comprises: When receiving a trigger signal input by a user, the programmable logic device reads out the data pre-stored in the memory in sequence according to the first frequency control word under the system clock, and forms a normalized discrete Gaussian waveform.

10. The method according to any one of claims 1 to 9, characterized in that: The programmable logic device includes any one of a field programmable gate array, a complex programmable logic device and an erasable programmable logic device, and the memory includes a ROM memory.

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