CN115700385A - Method for acquiring direct current crosstalk coefficient and direct current crosstalk matrix between quantum bits - Google Patents
Method for acquiring direct current crosstalk coefficient and direct current crosstalk matrix between quantum bits Download PDFInfo
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Abstract
The invention provides a method for acquiring a direct current crosstalk coefficient between quantum bits and a direct current crosstalk matrix, wherein when the direct current crosstalk coefficient between the quantum bits is acquired, one of a plurality of quantum bits on a quantum chip is determined as a target quantum bit, a first voltage is applied to the target quantum bit, another one of the plurality of quantum bits on the quantum chip is determined as an interference quantum bit, a second voltage is applied to the interference quantum bit, the working frequency of the target quantum bit is acquired based on a Ramsey experiment, a third voltage corresponding to the working frequency is acquired based on an energy spectrum curve of the target quantum bit, and the direct current crosstalk coefficient of the interference quantum bit to the target quantum bit is acquired based on the second voltage and the third voltage, so that when the frequency of the quantum bits is regulated, appropriate compensation operation is performed according to the direct current crosstalk coefficient, and the regulation and control of a magnetic flux regulation and control signal to the frequency of the quantum bits reach an expected value.
Description
Technical Field
The invention belongs to the technical field of quantum chip testing, and particularly relates to a method for acquiring direct current crosstalk coefficients and direct current crosstalk matrixes among quantum bits.
Background
In the prior art, a quantum chip is used as one of chips, is a basic constituent unit of a quantum computer, and is a processor which takes a superposition effect of quantum states as a principle and takes a quantum bit as an information processing carrier.
When two or more than two qubits exist on the qubit chip, a magnetic flux crosstalk phenomenon (namely, interference of a magnetic flux modulation signal applied on one qubit on another qubit) easily exists between the qubits, so that the uncertainty of qubit regulation is increased, and the regulation precision of the qubits is influenced. It is therefore necessary to perform a measurement analysis of the crosstalk between qubits on a superconducting quantum chip.
Disclosure of Invention
The invention aims to provide a method for acquiring a direct current crosstalk coefficient and a direct current crosstalk matrix between quantum bits, so as to solve the defects in the prior art, provide a reliable basis for regulation and control of the quantum bits and reduce uncertainty of regulation and control of the quantum bits.
In order to achieve the above object, in a first aspect, the present invention provides a method for obtaining a dc crosstalk coefficient between quantum bits, including:
determining one of a plurality of qubits on a qubit as a target qubit and applying a first voltage to the target qubit such that the target qubit has a first frequency at a flux modulation sensitive point;
determining another qubit in the plurality of qubits on the qubit chip as an interference qubit, and applying a second voltage to the interference qubit so that the interference qubit generates a dc crosstalk on the target qubit, affecting the first frequency;
obtaining the working frequency of the target qubit based on a Ramsey experiment, and obtaining a third voltage corresponding to the working frequency based on an energy spectrum curve of the target qubit, wherein the working frequency is the frequency of the target qubit after the first frequency is affected by the second voltage, and the energy spectrum curve is a variation curve of the frequency of the qubit with the voltage;
and acquiring the direct current crosstalk coefficient of the interference qubit to the target qubit based on the second voltage and the third voltage.
Optionally, determining one qubit in multiple qubits on the qubit as a target qubit, and applying a first voltage to the target qubit, so that the target qubit has a first frequency at the flux modulation sensitive point, specifically including:
determining one qubit in a plurality of qubits on a quantum chip as a target qubit;
determining a first working point of the target qubit, wherein the first working point is a working point near a flux modulation sensitive point of the target qubit;
and determining the voltage corresponding to the first working point as the first voltage, applying the first voltage to the target qubit, and adjusting the first voltage to make the frequency of the target qubit equal to the first frequency corresponding to the flux modulation sensitive point.
Optionally, the determining the first working point of the target qubit specifically includes:
determining a degenerate working point of the target qubit according to the energy spectrum curve of the target qubit;
determining the magnetic flux modulation sensitive point according to the degenerate working point and a preset frequency deviation;
and determining the first working point according to the magnetic flux modulation sensitive point.
Optionally, the energy spectrum curve is an energy spectrum curve after the frequency of the target qubit is affected by the second voltage.
Optionally, before obtaining the dc crosstalk coefficient of the interference qubit to the target qubit based on the second voltage and the third voltage, the method further includes:
adjusting the second voltage;
and returning to the step of executing the Ramsey-based experiment to obtain the working frequency of the target qubit and obtaining a third voltage corresponding to the working frequency based on the energy spectrum curve of the target qubit.
Optionally, before obtaining the dc crosstalk coefficient of the interference qubit to the target qubit based on the second voltage and the third voltage, the method further includes:
determining the second voltage and the third voltage as a group of data to be processed, and updating a database to be processed;
determining that the data volume threshold of the data to be processed is Z, determining that the total number of the data to be processed in the database to be processed is M, and judging whether M is larger than or equal to Z;
if so, executing a step of obtaining a direct current crosstalk coefficient of the interference qubit to the target qubit according to the second voltage and the third voltage;
if not, returning to the step of adjusting the second voltage.
Optionally, obtaining the dc crosstalk coefficient of the interference qubit to the target qubit based on the second voltage and the third voltage specifically includes:
performing linear fitting on the second voltage and the corresponding third voltage according to the M groups of data to be processed;
and obtaining the slope of the linear relation between the second voltage and the third voltage, and recording the slope as the direct current crosstalk coefficient of the interference qubit to the target qubit.
In a second aspect, the present invention provides a method for obtaining a dc crosstalk matrix between quantum bits, including:
determining an ith qubit of N qubits on a qubit chip as a target qubit and applying a first voltage to the target qubit such that the target qubit has a first frequency at a flux modulation sensitive point, N being an integer greater than or equal to 2;
determining a kth qubit of the N qubits on the qubit chip as an interference qubit and applying a second voltage to the interference qubit such that the interference qubit produces DC crosstalk on the target qubit affecting the first frequency, i ≠ k;
obtaining an operating frequency of the target qubit based on a Ramsey experiment, and obtaining a third voltage corresponding to the operating frequency based on an energy spectrum curve of the target qubit, wherein the operating frequency is a frequency of the target qubit after being influenced by the second voltage, and the energy spectrum curve is a variation spectral line of the frequency of the qubit with the voltage;
acquiring a direct-current crosstalk coefficient of the interference qubit to a target qubit based on the second voltage and the third voltage;
judging whether the direct current crosstalk coefficients of all the rest qubits except the ith qubit on the quantum chip to the ith qubit are obtained or not;
if not, reselecting the kth qubit, returning to the step of determining the kth qubit in the N qubits on the qubit as an interference qubit, and applying a second voltage to the interference qubit to enable the interference qubit to generate DC crosstalk on the target qubit and influence the first frequency, wherein i ≠ k;
if yes, judging whether the direct current crosstalk coefficients among the N qubits are all obtained;
if not, reselecting the ith qubit, and returning to determine the ith qubit in N qubits on the qubit chip as a target qubit, and applying a first voltage to the target qubit so that the target qubit has a first frequency at the flux modulation sensitive point, wherein N is an integer greater than or equal to 2;
and if so, generating a direct current crosstalk matrix based on all the obtained direct current crosstalk coefficients.
In a third aspect, the present invention provides a device for measuring dc crosstalk coefficient between quantum bits, including:
a first voltage determination module for determining one of a plurality of qubits on a qubit as a target qubit and applying a first voltage to the target qubit so that the target qubit has a first frequency at the flux modulation sensitive point;
a second voltage determination module for determining another qubit of the plurality of qubits on the qubit chip as an interfering qubit and applying a second voltage to the interfering qubit to cause the interfering qubit to generate DC crosstalk on the target qubit affecting the first frequency;
a third voltage determining module, configured to obtain an operating frequency of the target qubit based on a Ramsey experiment, and obtain a third voltage corresponding to the operating frequency based on an energy spectrum curve of the target qubit, where the operating frequency is a frequency of the target qubit after being affected by the second voltage, and the energy spectrum curve is a variation curve of the frequency of the qubit with voltage;
a first obtaining module, configured to obtain a dc crosstalk coefficient of the interference qubit to a target qubit based on the second voltage and the third voltage.
In a fourth aspect, the present invention provides a quantum computer, implementing the method for obtaining the dc crosstalk coefficient between qubits according to the first aspect, or implementing the method for obtaining the dc crosstalk matrix between qubits according to the second aspect, or including the apparatus for obtaining the dc crosstalk coefficient between qubits according to the third aspect.
Compared with the prior art, the method for acquiring the direct current crosstalk coefficient and the direct current crosstalk matrix between the quantum bits has the following beneficial effects: when a direct current crosstalk coefficient between qubits is obtained, firstly, one qubit in a plurality of qubits on a qubit chip is determined as a target qubit, a first voltage is applied to the target qubit, so that the target qubit has a first frequency at a magnetic flux modulation sensitive point, then, another qubit in the plurality of qubits on the qubit chip is determined as an interference qubit, a second voltage is applied to the interference qubit, so that the interference qubit generates direct current crosstalk on the target qubit to influence the first frequency, then, an operating frequency of the target qubit is obtained based on a Ramsey experiment, a third voltage corresponding to the operating frequency is obtained based on an energy spectrum curve of the target qubit, wherein the operating frequency is a frequency after the first frequency of the target qubit is influenced by the second voltage, the energy spectrum curve is a variation curve of the frequency of the qubit with voltage, and finally, the direct current crosstalk coefficient of the interference qubit is obtained based on the second voltage and the third voltage, so that the direct current crosstalk coefficient on the target qubit is conveniently compensated according to an expected direct current modulation control value.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a block diagram of a hardware structure of a computer terminal of a method for obtaining a dc crosstalk coefficient between quantum bits according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of a quantum chip according to an embodiment of the present invention;
fig. 3 is a schematic flowchart of a method for obtaining a dc crosstalk coefficient between quantum bits according to an embodiment of the present invention;
FIG. 4 is a graph of an energy spectrum of the target qubit according to an embodiment of the invention;
FIG. 5 is a schematic diagram of a process for determining a qubit in a plurality of qubits on a qubit chip as a target qubit and applying a first voltage to the target qubit so that the target qubit has a first frequency at a flux modulation sensitive point according to an embodiment of the present invention;
fig. 6 is a schematic flowchart of a process for determining a first operating point of the target qubit according to an embodiment of the present invention;
FIG. 7 is a schematic diagram of a process for retrieving data of the second voltage and the third voltage according to an embodiment of the present invention;
fig. 8 is a schematic flowchart of a process of obtaining a dc crosstalk coefficient of the interference qubit to the target qubit based on the second voltage and the third voltage according to an embodiment of the present invention;
FIG. 9 is a schematic diagram of a linear fit provided by an embodiment of the present invention;
fig. 10 is a flowchart illustrating a method for obtaining a dc crosstalk matrix between quantum bits according to an embodiment of the present invention;
fig. 11 is a schematic diagram of an apparatus for obtaining dc crosstalk coefficients between quantum bits according to an embodiment of the present invention;
description of reference numerals:
100-a computer terminal; 101-a processor; 102-a power supply; 103-a transmission device; 104-input-output devices; 105-memory, 200-acquisition means of the direct current crosstalk coefficient; 201-a first voltage determination module; 202-a second voltage determination module; 203-a third voltage determination module; 204-first obtaining module.
Detailed Description
The following describes the method for obtaining the dc crosstalk coefficient between the quantum bits and the dc crosstalk matrix according to the present invention in detail with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is merely for the purpose of facilitating and distinctly claiming the embodiments of the present invention.
In the description of the present invention, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to imply that the number of technical features indicated is significant. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
The method provided by the embodiment can be executed in a computer terminal or a similar operation device. Taking the example of the computer terminal, referring to fig. 1, the computer terminal 100 includes a power supply 102, which may include one or more processors 101 (only one is shown in fig. 1) (the processor 101 may include but is not limited to a processing device such as a micro-processing MCU or a programmable logic device FPGA), and a memory 105 for storing data, and optionally, the computer terminal 100 may further include a transmission device 103 for communication function and an input/output device 104. It will be understood by those skilled in the art that the structure shown in fig. 1 is only an illustration and is not intended to limit the structure of the computer terminal. For example, the computer terminal may also include more or fewer components than shown in FIG. 1, or have a different configuration than shown in FIG. 1.
The memory 105 may be used to store software programs and modules of application software, such as program instructions/modules corresponding to a method for determining multiple quantum bit measurement results provided in the present application, and the processor 101 executes various functional applications and data processing by executing the software programs and modules stored in the memory 105, so as to implement the method described above. Memory 105 may include high speed random access memory and may also include non-volatile solid state memory. In some embodiments, memory 105 may further include memory located remotely from the processor, which may be connected to a computer terminal over a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.
The transmission means 103 is used for receiving or sending data via a network. Specific examples of such networks may include wireless networks provided by the communications provider of the computer terminal. In one embodiment, the transmission device 103 includes a Network adapter (NIC) that can be connected to other Network devices through a base station so as to communicate with the internet. In one embodiment, the transmission device 103 may be a Radio Frequency (RF) module, which is used to communicate with the internet in a wireless manner.
The method provided by the embodiment can be applied to the computer terminal or a quantum computer.
In the quantum computer, referring to fig. 2, a plurality of one-to-one corresponding mutually coupled qubits are integrated on a quantum chip, and each qubit is coupled to an XY signal transmission line and a Z signal transmission line. The XY signal transmission line is used for receiving a quantum state regulation signal, the Z signal transmission line is used for receiving a magnetic flux regulation signal, the magnetic flux regulation signal comprises a direct current voltage bias signal and/or a pulse bias regulation signal, and the direct current voltage bias signal and the pulse bias regulation signal can regulate and control the frequency of the quantum bit.
In specific implementation, the direct-current voltage bias signal is applied through a Z signal transmission line to regulate and control the frequency of the qubit in a large range, so that the frequency of the qubit reaches the vicinity of the degenerate working point frequency; and then the pulse bias regulation and control signal is applied through a Z signal transmission line to regulate and control the frequency of the qubit in a small range, so that the frequency of the qubit accurately reaches the frequency of a degenerate working point. In summary, the frequency of the qubit is more accurately controlled by the coarse adjustment of the dc voltage bias signal and the fine adjustment of the pulse bias control signal.
Specifically, the qubit includes, but is not limited to, a structure composed of josephson junctions, and the structure composed of josephson junctions may be a single josephson junction, or a serial chain structure composed of a plurality of josephson junctions, or a closed loop structure composed of at least two parallel josephson junctions. Therein, the closed loop structure formed by at least two josephson junctions connected in parallel is also referred to as superconducting quantum interferometer (SQUID).
The qubit described in this embodiment includes, but is not limited to, a structure formed by a SQUID. And the SQUID and the Z signal transmission lines of other qubits have mutual inductance coupling effect. When a magnetic flux regulation signal is provided through the Z signal transmission line, the magnetic flux regulation signal generates a magnetic field, the magnetic field and the closed loop structure generate mutual inductance coupling, and the magnetic flux in the closed loop structure changes with the change of the magnetic flux regulation signal, so as to realize the regulation and control of the frequency of the qubit through the magnetic flux regulation signal, which may refer to the following formula:
wherein, V flux Is the voltage value of the magnetic flux modulation signal; f (V) flux ) Is the frequency of the superconducting qubit, and C, D, a, b, D are constants.
From the above equation, it can be seen that applying both the DC voltage bias signal and the pulse bias control signal changes V flux The frequency of the qubit can thus be adjusted. The direct-current voltage bias signal is used for regulating and controlling the frequency of the qubit in a large range, and the pulse bias regulation signal is used for regulating and controlling the frequency of the qubit in a small range.
In an actual quantum chip, a plurality of quantum bits exist on one quantum chip, and the magnetic flux modulation signal of each quantum bit influences the frequency of other quantum bits through space induction and a non-ideal ground plane reflux mode. Because the range of the frequency regulation of the direct current voltage bias signal on the qubit is larger, the crosstalk influence of the direct current voltage bias signal on other qubits is more serious when the qubit is tested.
The core idea of the invention is to provide a method for obtaining a direct current crosstalk coefficient and a direct current crosstalk matrix between qubits, and specifically, on the premise that the magnitude of the pulse bias signal on a Z signal transmission line corresponding to each qubit is set to be a first constant, the direct current crosstalk coefficient and the direct current crosstalk matrix between the qubits are obtained, so that when the frequency of the qubits is regulated, appropriate compensation operation is performed, and the regulation of the frequency of the qubits by a magnetic flux regulation and control signal reaches an expected value. The reason why the magnitude of the pulse bias signal on the Z signal transmission line corresponding to each qubit is set to the first constant is to make the crosstalk influence of the pulse bias signal applied to any one qubit on other qubits constant and the same when the dc crosstalk test is performed, thereby avoiding interference with the dc crosstalk test, and preferably, the first constant is 0.
Therefore, the present invention provides a method for obtaining a dc crosstalk coefficient between quantum bits, please refer to fig. 3, where the method includes the following steps:
step S10, determining one qubit of the plurality of qubits on the qubit as a target qubit, and applying a first voltage to the target qubit so that the target qubit has a first frequency at the flux modulation sensitive point.
Specifically, a plurality of qubits are arranged on the quantum chip, each qubit is coupled with a Z signal transmission line, any one of the qubits is used as a target qubit, and a first voltage is applied to the target qubit through the corresponding Z signal transmission line, so that the target qubit has a first frequency at the magnetic flux modulation sensitive point. Wherein the first voltage is a fixed value.
More specifically, referring to fig. 4, the flux modulation sensitive point is a position where the slope of the curve of the frequency of the qubit with voltage in fig. 2 is larger and is located on the right half of the curve (i.e., the reciprocal at the flux modulation sensitive point is a negative number).
In addition, it can be understood that the reason for having the target qubit at the first frequency of the flux modulation sensitive point is that at the flux modulation sensitive point, the target qubit is most sensitive to voltage variations, with frequency fluctuations being most pronounced. Therefore, in the flux modulation sensitive point, the influence of other qubits on the target qubit is also most obvious, so that the result is more accurate when the crosstalk coefficients generated by other qubits on the target qubit are obtained. It should be noted that the target qubit cannot be placed at an excessively sensitive working point, otherwise the frequency of the qubit is influenced by noise, has large fluctuation and short coherence time, and is not beneficial to measurement, and generally, a working point 50MHz away from the degenerate working point of the target qubit is taken as a magnetic flux modulation sensitive point, and when the target qubit is located at the working point, the effect of obtaining the crosstalk coefficient of the rest qubits on the target qubit is best according to repeated experimental experience of an inventor.
Step S20, determining another qubit in the multiple qubits on the qubit chip as an interference qubit, and applying a second voltage to the interference qubit, so that the interference qubit generates dc crosstalk on the target qubit to affect the first frequency.
Specifically, any one of the qubits except the target qubit is used as an interference qubit, and a second voltage is applied to the Z signal transmission line corresponding to the interference qubit, so that the interference qubit generates dc crosstalk on the target qubit. Specifically, the second voltage is a single voltage value with adjustable magnitude.
Step S30, obtaining the working frequency of the target qubit based on a Ramsey experiment, and obtaining a third voltage corresponding to the working frequency based on an energy spectrum curve of the target qubit, wherein the working frequency is the frequency of the target qubit after the first frequency is influenced by the second voltage, and the energy spectrum curve is a variation curve of the frequency of the qubit along with the voltage.
The Ramsey experiment refers to a process of applying two pi/2 quantum logic gate operations to a qubit, wherein the time interval of the two operations is tau, simultaneously applying a reading pulse to the qubit after the second pi/2 quantum logic gate operation to obtain an excited state distribution P1 (tau) of the qubit, and changing the time interval tau to obtain P1 (tau).
The result of a typical Ramsey experiment is that P1 (τ) is a mathematical model that satisfies exponential oscillation decay over time interval τ as follows:
in the above formula, A and B are fitting coefficients, T 0 Is the decoherence time of a qubit, f d Carrier frequency, f, of microwave pulse signal corresponding to pi/2 quantum logic gate operation 0 Is the oscillation frequency of the qubit, and f 0 With the true frequency f of the qubit q Carrier frequency f for pi/2 quantum logic gate operation d Satisfies the following conditions:
f 0 (f d )＝|f q -f d |
in conclusion, an important conclusion can be reached: results of Ramsey experiments, i.e. P 1 The oscillation frequency of the (tau) curve is equal to the difference between the carrier frequency of the operation of the quantum logic gate and the actual frequency of the qubit, so that the Ramsey experiment can be used for obtaining the decoherence time of the qubit and simultaneously and accurately obtaining the working frequency of the qubit.
Specifically, in this embodiment, the operating frequency of the target qubit, that is, the true operating frequency of the target qubit after the first frequency of the target qubit is affected by the second voltage crosstalk, may be obtained based on a Ramsey experiment. Then, a third voltage corresponding to the working frequency is obtained based on the energy spectrum curve of the target qubit, referring to fig. 3, the energy spectrum curve is a variation curve of the frequency of the qubit along with the voltage, and the frequency and the voltage are in a one-to-one correspondence relationship, so that it is known that the working frequency of the target qubit can correspondingly find the corresponding third voltage. And the energy spectrum curve of the quantum bit can also be obtained through Ramsey experiments.
And S40, acquiring a direct current crosstalk coefficient of the interference qubit to the target qubit based on the second voltage and the third voltage.
Specifically, it is known that when the second voltage is not applied to the Z signal transmission line of the interference qubit, that is, when the second voltage is 0, the frequency of the target qubit is the first frequency, and the corresponding voltage is the first voltage (for example, the first voltage is a fixed value V), where it is to be noted that this setting is equivalent to when the second voltage is 0, and the third voltage is V; after the second voltage (for example, the added second voltage is V1) different from 0 is applied to the Z signal transmission line of the interference qubit, the frequency of the target qubit fluctuates after being subjected to crosstalk thereof, at this time, the frequency of the target qubit changes from the first frequency to the operating frequency, and the voltage corresponding to the operating frequency is a third voltage (for example, the obtained third voltage is V2).
In summary, two specific coordinate point data (0, V) and (V1, V2) can be obtained, and the second voltage is set as V x And as an independent variable, setting the third voltage to V y And as a dependent variable, comparing the second voltage V based on the two coordinate point data x And said third voltage V y Linear fitting is performed to obtain a linear equation: v y ＝V+C*V x And the value of the slope C of the linear equation is the crosstalk coefficient of the interference qubit to the target qubit.
For example, referring to fig. 5, determining one qubit of a plurality of qubits on a qubit chip as a target qubit, and applying a first voltage to the target qubit so that the target qubit has a first frequency at a flux modulation sensitive point, specifically includes the following steps:
step S101, determining one quantum bit of a plurality of quantum bits on the quantum chip as a target quantum bit.
Step S102, determining a first working point of the target qubit, wherein the first working point is a working point near a flux modulation sensitive point of the target qubit.
Specifically, as described above, an operating point 50MHz away from the degenerate operating point of the target qubit is generally used as the flux modulation sensitive point, and an operating point near the flux modulation sensitive point is selected as the first operating point, specifically, the first operating point is an operating point within ± 5MHz away from the flux modulation sensitive point.
Step S103, determining a voltage corresponding to the first operating point as the first voltage, applying the first voltage to the target qubit, and adjusting the first voltage to make the frequency of the target qubit equal to the first frequency corresponding to the flux modulation sensitive point.
Specifically, a first voltage corresponding to the first operating point is obtained according to the frequency of the first operating point and the energy spectrum curve of the target qubit, the first voltage is applied to the target qubit through a Z signal transmission line coupled to the target qubit, then a current frequency value of the target qubit is obtained in real time based on a Ramsey experiment, and if the first voltage deviates from the first frequency, that is, the first voltage applied currently does not meet the requirement, the value of the first voltage is continuously adjusted until the applied first voltage meets the requirement that the frequency of the target qubit is equal to the first frequency corresponding to the flux modulation sensitive point.
For example, referring to fig. 6, the determining the first working point of the target qubit specifically includes the following steps:
step S1011, determining a degenerate working point of the target qubit according to the energy spectrum curve of the target qubit.
Specifically, an energy spectrum curve of the target qubit is obtained based on the Ramsey experiment, please refer to fig. 2, a position on the energy spectrum curve where the frequency is the largest, that is, a vertex of the curve shown in fig. 2 is defined as a degenerate working point of the target qubit, where a variation of the frequency of the target qubit along with a change of an applied voltage is very small and the sensitivity to noise is the lowest, so that a point near the degenerate working point cannot be selected as the first working point in the method for obtaining a dc crosstalk coefficient between qubits provided in this embodiment, and only the degenerate working point can be used as a reference point for selecting the magnetic flux modulation sensitive point.
Step S1012, determining the magnetic flux modulation sensitive point according to the degenerate operating point and a preset frequency deviation.
Specifically, the preset frequency deviation is 40-60 MHz, when the magnetic flux modulation sensitive point is selected, all points, within the preset frequency deviation range, of the numerical value of the frequency deviating from the degenerate point can be used as the magnetic flux modulation sensitive point, and preferably, the working point deviating from the degenerate working point of the target qubit by 50MHz is used as the magnetic flux modulation sensitive point.
Step S1013, determining the first operating point according to the magnetic flux modulation sensitive point.
Specifically, the working point of the magnetic flux modulation sensitive point accessory is selected as the first working point, and specifically, the first working point is a working point deviating from the magnetic flux modulation sensitive point within a range of +/-5 MHz.
Illustratively, the energy spectrum curve is an energy spectrum curve after the frequency of the target qubit is affected by the second voltage.
Specifically, the energy spectrum curve of the target qubit may change after being affected by the second voltage crosstalk, specifically, the energy spectrum curve may shift along a transverse coordinate axis. It can be understood that, in step S30, the operating frequency of the target qubit is obtained based on a Ramsey experiment, and the value of the third voltage corresponding to the operating frequency is obtained more accurately based on the energy spectrum curve after the frequency of the target qubit is affected by the second voltage, and then the dc crosstalk coefficient of the interference qubit to the target qubit is obtained more accurately based on the second voltage and the third voltage.
For example, referring to fig. 7, before obtaining the dc crosstalk coefficient of the interference qubit to the target qubit based on the second voltage and the third voltage, the method further includes:
step S31, adjusting the second voltage.
Specifically, the second voltage is a single voltage value with adjustable magnitude, and the magnitude of the voltage value of the second voltage is adjusted through a signal generator.
Step S32, returning to the step of obtaining the working frequency of the target qubit based on the Ramsey experiment and obtaining a third voltage corresponding to the working frequency based on the energy spectrum curve of the target qubit, that is, returning to the step S30.
Therefore, by adjusting the voltage value of the second voltage, the crosstalk influence amplitude of the second voltage on the frequency of the target qubit can be changed, a set of new data about the target qubit affected by the crosstalk of the second voltage is obtained, and then when a direct current crosstalk coefficient between qubits is obtained based on the second voltage and the third voltage, linear fitting can be performed based on multiple sets of data about the second voltage and the third voltage, so as to improve the accuracy of the crosstalk coefficient.
And step S33, determining the second voltage and the third voltage as a group of data to be processed, and updating a database to be processed.
Step S34, determining that the threshold value of the data volume of the data to be processed is Z, determining that the total number of the data to be processed in the database to be processed is M, and judging whether M is larger than or equal to Z.
If yes, a step of obtaining a direct current crosstalk coefficient of the interference qubit to the target qubit according to the second voltage and the third voltage is executed, that is, step S40 is executed.
If not, returning to the step of adjusting the second voltage, namely executing the step S31.
Therefore, through the circulation, a plurality of groups of second voltage data and third voltage data can be obtained, and then linear fitting is carried out on the second voltage data and the third voltage data based on the plurality of groups, so that a more accurate linear relation between the second voltage data and the third voltage data can be obtained, and a more accurate crosstalk coefficient of the interference qubit on the target qubit can be obtained, so that proper compensation operation can be carried out when the frequency of the qubit is regulated, and the regulation of the frequency of the qubit by the magnetic flux regulation and control signal can reach an expected value.
For example, referring to fig. 8, obtaining the dc crosstalk coefficient of the interference qubit to the target qubit based on the second voltage and the third voltage specifically includes:
step S401, according to the M groups of data to be processed, linear fitting is carried out on the second voltage and the corresponding third voltage.
Specifically, please refer to fig. 9, the M groups of the data to be processed are distributed in a straight lineIn an angular coordinate system, then finding the independent variable V by using a general least square method x And dependent variable V y V functional relation between y ＝f(V x ) From this functional relationship, a straight line can be determined, which is a linearly fitted straight line.
Step S402, obtaining a slope of a linear relation between the second voltage and the third voltage, and recording the slope as a direct current crosstalk coefficient of the interference qubit to the target qubit.
Specifically, the slope of the linear relationship between the second voltage and the third voltage is obtained according to a linearly fitted straight line, and the slope is recorded as a direct current crosstalk coefficient of the interference qubit to the target qubit.
Based on the same inventive concept, the present embodiment further provides a method for acquiring a dc crosstalk matrix between quantum bits, please refer to fig. 10, where the method includes the following steps:
step S1, determining the ith qubit in N qubits on a quantum chip as a target qubit, and applying a first voltage to the target qubit so that the target qubit has a first frequency at a flux modulation sensitive point, wherein N is an integer greater than or equal to 2.
Step S2, determining a kth qubit of the N qubits on the qubit as an interference qubit, and applying a second voltage to the interference qubit, so that the interference qubit generates DC crosstalk on the target qubit, affecting the first frequency, i ≠ k.
And S3, obtaining the working frequency of the target qubit based on a Ramsey experiment, and obtaining a third voltage corresponding to the working frequency based on an energy spectrum curve of the target qubit, wherein the working frequency is the frequency of the target qubit after the first frequency is influenced by the second voltage, and the energy spectrum curve is a variation spectral line of the frequency of the qubit along with the voltage.
And S4, acquiring a direct current crosstalk coefficient of the interference qubit to the target qubit based on the second voltage and the third voltage.
And S5, judging whether the direct current crosstalk coefficients of all the rest qubits except the ith qubit on the quantum chip to the ith qubit are acquired or not.
If not, reselecting the k-th qubit, returning to the step of determining the k-th qubit in the N qubits on the qubit chip as an interference qubit, and applying a second voltage to the interference qubit, so that the interference qubit generates DC crosstalk on the target qubit, affecting the first frequency, i ≠ k, i.e. performing step S2.
If yes, step S6 is executed to determine whether the dc crosstalk coefficients between the N qubits have been obtained.
If not, reselecting the ith qubit, and returning to determine the ith qubit of the N qubits on the qubit chip as a target qubit, and applying a first voltage to the target qubit so that the target qubit has a first frequency at the flux modulation sensitive point, wherein N is an integer greater than or equal to 2, namely executing step S1.
If yes, step S7 is executed to generate a dc crosstalk matrix based on all the acquired dc crosstalk coefficients.
In summary, for example, if there are N qubits on the quantum chip, the dc crosstalk matrix generated based on the dc crosstalk coefficients between the acquired qubits is an N × N square matrix, where each dc crosstalk coefficient is an element constituting the dc crosstalk matrix, and for the superconducting quantum chip including the N qubits, the dc crosstalk coefficient is denoted as C ij (1≤i,j≤N)，C ij The element in the ith row and the jth column of the dc crosstalk matrix represents the crosstalk coefficient of the jth qubit to the jth qubit. It is understood that when i = j, C ij 1, i.e. the diagonal values of the N x N matrix are all 1.
Based on the same inventive concept, the present embodiment further provides an apparatus for obtaining dc crosstalk coefficient between quantum bits, referring to fig. 11, the apparatus 200 for obtaining dc crosstalk coefficient includes:
a first voltage determination module 201, configured to determine one qubit of a plurality of qubits on a qubit chip as a target qubit, and apply a first voltage to the target qubit so that the target qubit has a first frequency at the flux modulation sensitive point.
A second voltage determination module 202 configured to determine another qubit of the plurality of qubits on the qubit as an interfering qubit and apply a second voltage to the interfering qubit such that the interfering qubit causes DC crosstalk on the target qubit affecting the first frequency.
A third voltage determining module 203, configured to obtain an operating frequency of the target qubit based on a Ramsey experiment, and obtain a third voltage corresponding to the operating frequency based on an energy spectrum curve of the target qubit, where the operating frequency is a frequency of the target qubit after the first frequency is affected by the second voltage, and the energy spectrum curve is a variation curve of the frequency of the qubit with voltage.
A first obtaining module 204, configured to obtain a dc crosstalk coefficient of the interference qubit to the target qubit based on the second voltage and the third voltage.
Based on the same inventive concept, the present embodiment further provides a quantum computer, which implements the method for acquiring a dc crosstalk coefficient as described above, or implements the method for acquiring a dc crosstalk matrix as described above, or includes the apparatus for acquiring a dc crosstalk coefficient as described above.
In summary, the method for obtaining the dc crosstalk coefficient and the dc crosstalk matrix between the quantum bits provided by the present invention has the following advantages: when a direct current crosstalk coefficient between qubits is obtained, firstly, one qubit in a plurality of qubits on a qubit chip is determined as a target qubit, a first voltage is applied to the target qubit, so that the target qubit has a first frequency at a magnetic flux modulation sensitive point, then, another qubit in the plurality of qubits on the qubit chip is determined as an interference qubit, a second voltage is applied to the interference qubit, so that the interference qubit generates direct current crosstalk on the target qubit to influence the first frequency, then, an operating frequency of the target qubit is obtained based on a Ramsey experiment, a third voltage corresponding to the operating frequency is obtained based on an energy spectrum curve of the target qubit, wherein the operating frequency is a frequency after the first frequency of the target qubit is influenced by the second voltage, the energy spectrum curve is a variation curve of the frequency of the qubit with voltage, and finally, the direct current crosstalk coefficient of the interference qubit is obtained based on the second voltage and the third voltage, so that the direct current crosstalk coefficient on the target qubit is conveniently compensated according to an expected direct current modulation control value.
The above description is only for the purpose of describing the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention, and any variations and modifications made by those skilled in the art based on the above disclosure are within the scope of the appended claims.
Claims (10)
1. A method for obtaining direct current crosstalk coefficients between quantum bits is characterized by comprising the following steps:
determining one qubit in a plurality of qubits on a qubit chip as a target qubit and applying a first voltage to the target qubit so that the target qubit has a first frequency at a flux modulation sensitive point;
determining another qubit in the plurality of qubits on the qubit as an interference qubit, and applying a second voltage to the interference qubit to cause the interference qubit to generate dc crosstalk on the target qubit affecting the first frequency;
obtaining an operating frequency of the target qubit based on a Ramsey experiment, and obtaining a third voltage corresponding to the operating frequency based on an energy spectrum curve of the target qubit, wherein the operating frequency is a frequency of the target qubit after being influenced by the second voltage, and the energy spectrum curve is a variation curve of the frequency of the qubit with voltage;
and acquiring the direct current crosstalk coefficient of the interference qubit to the target qubit based on the second voltage and the third voltage.
2. The method of claim 1, wherein determining one of a plurality of qubits on a qubit as a target qubit and applying a first voltage to the target qubit to cause the target qubit to have a first frequency at the flux modulation sensitive point comprises:
determining one qubit in a plurality of qubits on a quantum chip as a target qubit;
determining a first working point of the target qubit, wherein the first working point is a working point near a flux modulation sensitive point of the target qubit;
determining a voltage corresponding to the first operating point as the first voltage and applying the first voltage to the target qubit and adjusting the first voltage such that the frequency of the target qubit is equal to the first frequency corresponding to the flux modulation sensitive point.
3. The method for acquiring the dc crosstalk coefficient between the qubits according to claim 2, wherein the determining the first operating point of the target qubit specifically comprises:
determining a degenerate working point of the target qubit according to the energy spectrum curve of the target qubit;
determining the magnetic flux modulation sensitive point according to the degenerate working point and a preset frequency deviation;
and determining the first working point according to the magnetic flux modulation sensitive point.
4. The method according to claim 1, wherein the energy spectrum curve is an energy spectrum curve of the target qubit after the frequency of the target qubit is affected by the second voltage.
5. The method of claim 1, wherein before obtaining the dc crosstalk coefficient between the interfering qubits and the target qubit based on the second voltage and the third voltage, further comprising:
adjusting the second voltage;
and returning to the step of executing the Ramsey-based experiment to obtain the working frequency of the target qubit and obtaining a third voltage corresponding to the working frequency based on the energy spectrum curve of the target qubit.
6. The method of claim 5, wherein before obtaining the DC crosstalk coefficient between the interference qubit and the target qubit based on the second voltage and the third voltage, further comprising:
determining the second voltage and the third voltage as a group of data to be processed, and updating a database to be processed;
determining that the data volume threshold of the data to be processed is Z, determining that the total number of the data to be processed in the database to be processed is M, and judging whether M is larger than or equal to Z;
if so, executing a step of obtaining a direct current crosstalk coefficient of the interference qubit to the target qubit according to the second voltage and the third voltage;
if not, returning to the step of adjusting the second voltage.
7. The method according to claim 6, wherein the obtaining of the dc crosstalk coefficient between the interference qubits and the target qubit based on the second voltage and the third voltage specifically comprises:
performing linear fitting on the second voltage and a corresponding third voltage according to the M groups of data to be processed;
and obtaining the slope of the linear relation between the second voltage and the third voltage, and recording the slope as the direct current crosstalk coefficient of the interference qubit to the target qubit.
8. A method for acquiring a direct current crosstalk matrix between quantum bits is characterized by comprising the following steps:
determining an ith qubit of N qubits on a qubit chip as a target qubit and applying a first voltage to the target qubit such that the target qubit has a first frequency at a flux modulation sensitive point, N being an integer greater than or equal to 2;
determining a kth qubit of the N qubits on the qubit chip as an interference qubit and applying a second voltage to the interference qubit such that the interference qubit produces DC crosstalk on the target qubit affecting the first frequency, i ≠ k;
obtaining the working frequency of the target qubit based on a Ramsey experiment, and obtaining a third voltage corresponding to the working frequency based on an energy spectrum curve of the target qubit, wherein the working frequency is the frequency of the target qubit after the first frequency is influenced by the second voltage, and the energy spectrum curve is a spectral line of the frequency of the qubit along with the voltage;
acquiring a direct-current crosstalk coefficient of the interference qubit to a target qubit based on the second voltage and the third voltage;
judging whether the direct current crosstalk coefficients of all the rest qubits except the ith qubit on the quantum chip to the ith qubit are obtained or not;
if not, reselecting the k-th qubit, returning to the determining that the k-th qubit in the N qubits on the qubit chip is used as an interference qubit, and applying a second voltage to the interference qubit so that the interference qubit generates DC crosstalk on the target qubit to affect the first frequency, i ≠ k;
if yes, judging whether the direct current crosstalk coefficients among the N qubits are all obtained;
if not, reselecting the ith qubit, and returning to determine the ith qubit in N qubits on the qubit chip as a target qubit, and applying a first voltage to the target qubit so that the target qubit has a first frequency at the flux modulation sensitive point, wherein N is an integer greater than or equal to 2;
and if so, generating a direct current crosstalk matrix based on all the obtained direct current crosstalk coefficients.
9. An apparatus for measuring a dc crosstalk coefficient between qubits, comprising:
a first voltage determination module for determining one of a plurality of qubits on a qubit chip as a target qubit and applying a first voltage to the target qubit so that the target qubit has a first frequency at a flux modulation sensitive point;
a second voltage determination module for determining another qubit of the plurality of qubits on the qubit chip as an interfering qubit and applying a second voltage to the interfering qubit to cause the interfering qubit to generate DC crosstalk on the target qubit affecting the first frequency;
a third voltage determining module, configured to obtain an operating frequency of the target qubit based on a Ramsey experiment, and obtain a third voltage corresponding to the operating frequency based on an energy spectrum curve of the target qubit, where the operating frequency is a frequency of the target qubit after being affected by the second voltage, and the energy spectrum curve is a variation curve of the frequency of the qubit with voltage;
a first obtaining module, configured to obtain a dc crosstalk coefficient of the interference qubit to a target qubit based on the second voltage and the third voltage.
10. A quantum computer, characterized by implementing the method for obtaining the dc crosstalk coefficient between qubits according to any one of claims 1 to 7, or implementing the method for obtaining the dc crosstalk matrix between qubits according to claim 8, or comprising the apparatus for obtaining the dc crosstalk coefficient between qubits according to claim 9.
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| PCT/CN2022/108248 WO2023005972A1 (en) | 2021-07-28 | 2022-07-27 | Method for determining crosstalk of quantum bits, quantum measurement and control system, and quantum computer |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116341668A (en) * | 2023-05-26 | 2023-06-27 | 苏州浪潮智能科技有限公司 | Quantum bit compensation method, device, equipment, medium and quantum system |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20050030884A1 (en) * | 2003-08-07 | 2005-02-10 | Quellan, Inc. | Method and system for crosstalk cancellation |
| WO2013185343A1 (en) * | 2012-06-15 | 2013-12-19 | 华为技术有限公司 | Method and device for suppressing pilot signal crosstalk, and pilot signal receiving device |
| CN104865441A (en) * | 2015-05-27 | 2015-08-26 | 中国科学院电工研究所 | Crosstalk spectrum calculation method |
| CN109406875A (en) * | 2018-10-15 | 2019-03-01 | 合肥本源量子计算科技有限责任公司 | Quantum bit transmitting frequency calibration method is carried out based on Ramsey interference experiment |
| CN112444738A (en) * | 2019-08-28 | 2021-03-05 | 合肥本源量子计算科技有限责任公司 | Method for verifying crosstalk residue of superconducting quantum chip |
| CN112444715A (en) * | 2019-08-28 | 2021-03-05 | 合肥本源量子计算科技有限责任公司 | Method for measuring crosstalk matrix of superconducting quantum chip |
-
2021
- 2021-07-28 CN CN202110855366.7A patent/CN115700385A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20050030884A1 (en) * | 2003-08-07 | 2005-02-10 | Quellan, Inc. | Method and system for crosstalk cancellation |
| WO2013185343A1 (en) * | 2012-06-15 | 2013-12-19 | 华为技术有限公司 | Method and device for suppressing pilot signal crosstalk, and pilot signal receiving device |
| CN104865441A (en) * | 2015-05-27 | 2015-08-26 | 中国科学院电工研究所 | Crosstalk spectrum calculation method |
| CN109406875A (en) * | 2018-10-15 | 2019-03-01 | 合肥本源量子计算科技有限责任公司 | Quantum bit transmitting frequency calibration method is carried out based on Ramsey interference experiment |
| CN112444738A (en) * | 2019-08-28 | 2021-03-05 | 合肥本源量子计算科技有限责任公司 | Method for verifying crosstalk residue of superconducting quantum chip |
| CN112444715A (en) * | 2019-08-28 | 2021-03-05 | 合肥本源量子计算科技有限责任公司 | Method for measuring crosstalk matrix of superconducting quantum chip |
Non-Patent Citations (1)
| Title |
|---|
| 王亚飞;赵彦晓;杨玮;李学华;: "耦合传输线信道传输矩阵建模及串扰抵消效果分析", 电子学报, no. 05 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116341668A (en) * | 2023-05-26 | 2023-06-27 | 苏州浪潮智能科技有限公司 | Quantum bit compensation method, device, equipment, medium and quantum system |
| CN116341668B (en) * | 2023-05-26 | 2023-08-15 | 苏州浪潮智能科技有限公司 | Quantum bit compensation method, device, equipment, medium and quantum system |
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