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CN-121998111-A - Quantum bit working frequency distribution method, system and quantum computer

CN121998111ACN 121998111 ACN121998111 ACN 121998111ACN-121998111-A

Abstract

The application discloses a method and a system for distributing the working frequency of a qubit and a quantum computer, belonging to the technical field of quantum computing; the distribution method comprises the steps of presetting an initial working frequency range of each qubit on a quantum processor, setting the working frequency of each qubit as the frequency initial value, calibrating logic gate parameters of the qubit according to a directed acyclic graph for each qubit, executing random reference test on the calibrated logic gate parameters, and obtaining that the frequency initial value when the fidelity of the quantum state of the qubit is within a preset threshold value is the working frequency to be distributed of the qubit. The working frequencies of the qubits distributed by the distribution method are all in proper working frequencies, so that the interference influence can be effectively reduced.

Inventors

  • KONG WEICHENG
  • Request for anonymity

Assignees

  • 本源量子计算科技（合肥）股份有限公司

Dates

Publication Date
20260508
Application Date
20241030

Claims (10)

  1. 1. A method of assigning a qubit operating frequency, comprising: Presetting an initial working frequency range of each qubit on a quantum processor, wherein the initial working frequency range comprises a plurality of frequency initial values; Setting the working frequency of the qubit as the frequency initial value, and calibrating the logic gate parameters of the qubit for each qubit according to a directed acyclic graph, wherein the directed acyclic graph comprises a plurality of node graphs formed by the qubit and the performance parameters of a resonant cavity coupled and connected with the qubit; And executing a random reference test on the calibrated logic gate parameters to obtain the frequency initial value of the quantum state of the quantum bit when the fidelity of the quantum state of the quantum bit is within a preset threshold value as the working frequency to be distributed of the quantum bit, wherein the random reference test is used for testing the corresponding relation between the fidelity of the quantum state of the quantum bit and the applied logic gate.
  2. 2. The method of claim 1, wherein presetting an initial operating frequency range for each qubit on the quantum processor comprises: acquiring a first frequency of each qubit, wherein the first frequency is a working frequency with which the frequency of the qubit has the minimum change rate along with a regulating signal applied to a magnetic flux modulation line; presetting the initial working frequency range according to the first frequency, wherein the first frequency is the cut-off frequency of the initial working frequency range.
  3. 3. The method of claim 1, wherein the logic gate parameters include characteristic parameters, read parameters, and control parameters of the qubit and the resonant cavity, setting the operating frequency of the qubit to the frequency initial value, respectively, and calibrating the logic gate parameters of the qubit according to a directed acyclic graph for each of the qubits, comprising: acquiring a directed acyclic graph comprising a plurality of nodes, wherein the directed acyclic graph comprises the characteristic parameters, the reading parameters and the control parameters; Traversing a plurality of frequency initial values in the initial working frequency range, and calibrating the characteristic parameters, the reading parameters and the control parameters in sequence according to the node sequence of the directed acyclic graph.
  4. 4. The method of claim 1, wherein performing a random reference test on the calibrated logic gate parameters comprises: traversing a driving signal applied to the qubit so that the working frequency of the qubit corresponds to each frequency initial value of the initial working frequency range; When the working frequency of the qubit is each frequency initial value, a logic gate combination and an inverse logic gate are applied to the qubit, wherein the logic gate combination comprises a plurality of single-quantum logic gates which are used for regulating and controlling the quantum state of the qubit from an initial state to a target state, and the inverse logic gate is used for regulating and controlling the quantum state of the qubit from the target state to the initial state; and measuring the fidelity of the quantum state of the qubit as an initial state.
  5. 5. The method of claim 4, wherein obtaining the initial frequency value for the fidelity of the quantum state of the qubit to be within a preset threshold is the operating frequency of the qubit to be allocated, comprising: Acquiring a preset threshold value; When the fidelity is within the preset threshold, determining the frequency initial value as a target working frequency, wherein a plurality of target working frequencies form a working frequency set to be distributed; And when the fidelity is not within the preset threshold, discarding the corresponding frequency initial value.
  6. 6. A method of characterizing a quantum processor, comprising: Obtaining a topological structure of a qubit on a quantum processor; The working frequency of each qubit is distributed according to the topological structure and by adopting the method for distributing the working frequency of the qubit according to any one of claims 1-5.
  7. 7. A system for distributing the operating frequency of a qubit, comprising: The device comprises a parameter acquisition module, a parameter generation module and a parameter generation module, wherein the parameter acquisition module is used for acquiring an initial working frequency range of each quantum bit on a preset quantum processor, and the initial working frequency range comprises a plurality of frequency initial values; the parameter calibration module is used for setting the working frequency of the qubit as the frequency initial value respectively and calibrating the logic gate parameter of the qubit according to a directed acyclic graph for each qubit, wherein the directed acyclic graph comprises a plurality of node diagrams consisting of the qubit and the performance parameters of a resonant cavity coupled and connected with the qubit; The frequency allocation module is used for executing random reference test on the logic gate parameters of the quantum bit to obtain the frequency initial value of the quantum state of the quantum bit when the fidelity of the quantum state of the quantum bit is within a preset threshold value as the working frequency to be allocated of the quantum bit, wherein the random reference test is the corresponding relation between the fidelity of the quantum state of the quantum bit and the applied logic gate.
  8. 8. A quantum computing measurement and control system, characterized by using the method for allocating the operating frequency of the qubit according to any one of claims 1 to 5, or comprising the system for allocating the operating frequency of the qubit according to claim 7.
  9. 9. A quantum computer comprising a quantum processor and a quantum computing measurement and control system as claimed in claim 8, or a method as claimed in claim 6 for characterising the operating frequency of qubits on the quantum processor.
  10. 10. A readable storage medium having stored thereon a computer program, which when executed by a processor is capable of implementing the method of any of claims 1-5 for assigning an operating frequency of a qubit on a quantum processor.

Description

Quantum bit working frequency distribution method, system and quantum computer Technical Field The application relates to the technical field of quantum computing, in particular to a method and a system for distributing working frequency of a quantum bit and a quantum computer. Background Quantum computation and quantum information are a cross subject for realizing computation and information processing tasks based on the principle of quantum mechanics, and have very close connection with subjects such as quantum physics, computer science, informatics and the like. There has been a rapid development in the last two decades. Quantum computer-based quantum algorithms in factorization, unstructured search, etc. scenarios exhibit far beyond the performance of existing classical computer-based algorithms, and this direction is expected to be beyond the existing computing power. Since quantum computing has the potential to solve certain problems far beyond the development of classical computer performance, in order to realize quantum computers, it is necessary to obtain a quantum processor containing a sufficient number and quality of qubits, and to enable extremely high fidelity quantum logic gate operation and readout of the qubits. Quantum processors are the core components of quantum computers, which are processors that perform quantum computation, and quantum computers are the traditional computers, which are the equivalent of CPUs. Before each quantum processor is formally used on line, each parameter of the qubit in the quantum processor needs to be tested and characterized. For each qubit in a quantum processor, it is desirable to implement as fast a qubit logic gate as possible in order to be able to perform as many computations as possible within the finite lifetime of the qubit. In general, the execution completion time of a qubit logic gate is typically three to four orders of magnitude faster than the qubit lifetime. However, fast qubit logic gate operations may cause the qubit logic gate to malfunction when executed. There are many reasons for the error of the qubit logic gate, such as parasitic coupling between nearest neighbor and next neighbor qubits, spectral diffusion two-stage system (TLS) defects, parasitic microwave modes, coupling to control lines and readout resonators, frequency control electronics noise, frequency control pulse distortion, microwave control pulse distortion, and microwave carrier leakage, etc. When each qubit in the quantum processor is at a proper working frequency, the interference influence can be effectively reduced. It should be noted that the information disclosed in the background section of the present application is only for enhancement of understanding of the general background of the present application and should not be taken as an admission or any form of suggestion that this information forms the prior art already known to those skilled in the art. Disclosure of Invention The application aims to provide a method and a system for distributing the working frequency of a quantum bit and a quantum computer, which can distribute the working frequency of the quantum bit on a quantum processor, so that when each quantum bit is at a proper working frequency, the interference influence is effectively reduced. In order to solve the technical problems, the technical scheme of the application is as follows: The first aspect of the present application provides a method for allocating a qubit operating frequency, including: Presetting an initial working frequency range of each qubit on a quantum processor, wherein the initial working frequency range comprises a plurality of frequency initial values; Setting the working frequency of the qubit as the frequency initial value, and calibrating the logic gate parameters of the qubit for each qubit according to a directed acyclic graph, wherein the directed acyclic graph comprises a plurality of node graphs formed by the qubit and the performance parameters of a resonant cavity coupled and connected with the qubit; And executing a random reference test on the calibrated logic gate parameters to obtain the frequency initial value of the quantum state of the quantum bit when the fidelity of the quantum state of the quantum bit is within a preset threshold value as the working frequency to be distributed of the quantum bit, wherein the random reference test is used for testing the corresponding relation between the fidelity of the quantum state of the quantum bit and the applied logic gate. The method as described above, optionally, presetting an initial operating frequency range of each qubit on the quantum processor, including: acquiring a first frequency of each qubit, wherein the first frequency is a working frequency with which the frequency of the qubit has the minimum change rate along with a regulating signal applied to a magnetic flux modulation line; presetting the initial working frequency range according to the first f