CN117172324A - Quantum circuit performance determining method, program and storage medium - Google Patents
Quantum circuit performance determining method, program and storage medium Download PDFInfo
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Abstract
The embodiment of the application provides a quantum circuit performance determining method, a program and a storage medium, and relates to the technical field of quantum chips. The method comprises the following steps: obtaining a low-temperature actually measured performance result of each quantum circuit of a group of quantum circuits; program simulation is carried out according to the characteristic parameters of each quantum circuit of the group of quantum circuits, so that a simulation value of each quantum circuit is obtained; comparing the low-temperature actually measured performance result of each quantum circuit with the simulation value of each quantum circuit, and determining one simulation value from the simulation value of each quantum circuit as a characteristic value; when a quantum circuit is newly designed, the performance of the newly designed quantum circuit can be determined only by comparing the relative magnitude relation between a specific parameter of the quantum circuit and a characteristic value obtained in advance, the newly designed quantum circuit is not required to be put into a low-temperature environment for actual measurement, the actual measurement cost is saved, and the research and development efficiency is improved.
Description
Technical Field
The application relates to the technical field of quantum chips, in particular to a method for determining the performance of a quantum circuit.
Background
The superconducting quantum chip is provided with various circuit structures, various parts of the circuit structures are provided with various optional design schemes, different design schemes can lead to different performances of the quantum chip, and some design schemes can lead to the problems of crosstalk and the like of signals in the quantum chip.
In order to ensure good performance of the quantum chip, various designs are usually required to be actually measured. However, the quantum chip needs to realize a superconducting state through extremely low temperature so as to be controlled to perform quantum computation and obtain a corresponding computation result through a reading operation. The performance of various components in the quantum chip is different from that of the quantum chip in a room temperature state and a superconducting state. It is difficult to accurately evaluate performance under low temperature superconductivity at room temperature. Therefore, the actual measurement cost of the quantum chip is high.
Therefore, in the design process, how to determine whether a design scheme of a quantum circuit has performance problems at low cost is a technical problem to be solved.
Disclosure of Invention
The application aims to provide a quantum circuit performance determining method for judging whether performance problems occur in some parameters in a quantum circuit or not at low cost.
In order to achieve the above purpose, the following technical scheme is adopted in the embodiment of the application.
In a first aspect, an embodiment of the present application provides a method for determining performance of a quantum circuit, including:
obtaining a low-temperature actually measured performance result of each quantum circuit of a group of quantum circuits; the group of quantum circuits comprises a plurality of quantum circuits with different characteristic parameters;
program simulation is carried out according to the characteristic parameters of each quantum circuit of the group of quantum circuits, so that a simulation value of each quantum circuit is obtained;
according to the comparison between the low-temperature actually-measured performance result of each quantum circuit and the simulation value of each quantum circuit, determining a simulation value from the simulation value of each quantum circuit as a characteristic value;
determining the performance of the newly designed quantum circuit according to the relative magnitude relation between the to-be-evaluated simulation value and the characteristic value of the newly designed quantum circuit; the simulation value to be evaluated is obtained by performing program simulation on the characteristic parameters of the newly designed quantum circuit.
Optionally, each of the quantum circuits comprises a first x-ray and a first qubit;
the low temperature measured performance results of each quantum circuit include: the first x-ray is capable of driving the first qubit, or the first x-ray is not capable of driving the first qubit;
program simulation is carried out according to the characteristic parameters of each quantum circuit of the group of quantum circuits, and the step of obtaining the simulation value of each quantum circuit comprises the following steps: program simulation is carried out according to the structural parameters of each quantum circuit of the group of quantum circuits, so as to obtain a mutual capacitance value between a first x-ray and a first quantum bit of each quantum circuit;
the step of determining a simulated value from the simulated values of each quantum circuit as a characteristic value based on a comparison of the measured performance result of each quantum circuit at the low temperature with the simulated value of each quantum circuit comprises: determining a first mutual capacitance value characteristic value according to the comparison between the low-temperature actually measured performance result of each quantum circuit and the mutual capacitance value of each quantum circuit;
according to the relative magnitude relation between the to-be-evaluated simulation value and the characteristic value of the newly designed quantum circuit, the step of determining the performance of the newly designed quantum circuit comprises the following steps: if the mutual capacitance value between the first x-ray of the newly designed quantum circuit and the first quantum bit is larger than or equal to the first mutual capacitance value characteristic value, determining that the first x-ray of the newly designed quantum circuit can drive the first quantum bit.
Optionally, the step of obtaining a low temperature measured performance result for each quantum circuit of the set of quantum circuits comprises:
and applying signals for driving the first quantum bits to the first x-rays in the quantum circuit one by one in the order that the mutual capacitance value between the first x-rays and the first quantum bits in the quantum circuit is gradually increased so as to find out the mutual capacitance value of the first quantum bits which the first x-rays can just drive, and recording the structural parameters of the quantum circuit which is driven by applying the signals each time and the result of whether the first x-rays in the quantum circuit can drive the first quantum bits in the quantum circuit.
Optionally, before the step of applying a signal driving the first qubit to the first x-ray in the quantum circuit, the quantum circuit performance determining method further comprises:
under the condition that the first x-ray in the quantum circuit can drive the first quantum bit, different frequency signals are added to the first x-ray of the quantum circuit, frequency points when frequency resonance is generated are observed, and then the bit frequency of the first quantum bit of the quantum circuit is determined through measuring the Laratio oscillation.
Optionally, the quantum circuit comprises a first x-ray, a first qubit, and a second x-ray; the projection of the second x-ray on the plane of the first qubit is intersected with the first qubit;
the low temperature measured performance results of each quantum circuit include: the second x-ray can drive the first qubit or the second x-ray cannot drive the first qubit;
program simulation is carried out according to the characteristic parameters of each quantum circuit of the group of quantum circuits, and the step of obtaining the simulation value of each quantum circuit comprises the following steps: program simulation is carried out according to the structural parameters of each quantum circuit of the group of quantum circuits, so as to obtain a mutual capacitance value between a second x-ray and a first quantum bit of each quantum circuit;
the step of determining a simulated value from the simulated values of each quantum circuit as a characteristic value based on a comparison of the measured performance result of each quantum circuit at the low temperature with the simulated value of each quantum circuit comprises: determining a second mutual capacitance value characteristic value according to the comparison between the low-temperature actually measured performance result of each quantum circuit and the mutual capacitance value of each quantum circuit;
according to the relative magnitude relation between the to-be-evaluated simulation value and the characteristic value of the newly designed quantum circuit, the step of determining the performance of the newly designed quantum circuit comprises the following steps: and if the mutual capacitance value between the second x-ray of the newly designed quantum circuit and the first quantum bit is larger than or equal to the second mutual capacitance value characteristic value, determining crosstalk between the second x-ray of the newly designed quantum circuit and the first quantum bit.
Optionally, the step of obtaining a low temperature measured performance result for each quantum circuit of the set of quantum circuits comprises:
and applying signals for driving the first quantum bits to the second x-rays in the quantum circuit one by one in the order of gradually increasing the mutual capacitance value between the second x-rays and the first quantum bits in the quantum circuit so as to find out the mutual capacitance value of the first quantum bits which can be just driven by the second x-rays, and recording the structural parameters of the quantum circuit which can be driven by the signals and the result of whether the first quantum bits can be driven by the second x-rays in the quantum circuit.
Optionally, the second x-rays in the quantum circuits comprise air bridges, the size of the air bridges of the second x-rays being different for each quantum circuit.
Optionally, the quantum circuit is a link formed by connecting a plurality of devices, each device having parameters of the device;
the low temperature measured performance results of each quantum circuit include: the signals in the link are distorted or the signals in the link are not distorted;
program simulation is carried out according to the characteristic parameters of each quantum circuit of the group of quantum circuits, and the step of obtaining the simulation value of each quantum circuit comprises the following steps: program simulation is carried out according to the working parameters of each quantum circuit, so that parameters of each device of each quantum circuit are obtained;
the step of determining a simulated value from the simulated values of each quantum circuit as a characteristic value based on a comparison of the measured performance result of each quantum circuit at the low temperature with the simulated value of each quantum circuit comprises: determining a maximum characteristic value and a minimum characteristic value of each device according to the low-temperature actually measured performance result of each quantum circuit and the parameter comparison of each device of each quantum circuit;
according to the relative magnitude relation between the to-be-evaluated simulation value and the characteristic value of the newly designed quantum circuit, the step of determining the performance of the newly designed quantum circuit comprises the following steps: and if the parameter of each device of the newly designed quantum circuit is between the minimum characteristic value and the maximum characteristic value, determining that the x signal of the quantum circuit is undistorted.
In a second aspect, embodiments of the present application provide a computer-readable storage medium having stored therein a computer program or instructions which, when executed by a computer, implement the quantum circuit performance determining method of the first aspect.
In a third aspect, embodiments of the present application provide a computer program comprising instructions which, when executed by a computer, implement the quantum circuit performance determining method of the first aspect.
Compared with the prior art, the application has the following beneficial effects:
according to the quantum circuit performance determining method provided by the embodiment of the application, when a quantum circuit is newly designed, the performance of the newly designed quantum circuit can be determined only by comparing the relative magnitude relation between a specific parameter of the quantum circuit and the characteristic value obtained in advance, and the newly designed quantum circuit is not required to be put into a low-temperature environment for actual measurement, so that the actual measurement cost is saved, and the research and development efficiency is improved.
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In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic diagram of a method for determining performance of a quantum circuit according to an embodiment of the present application;
FIG. 2 is a schematic diagram of a quantum circuit with a first x-ray and a first qubit according to an embodiment of the present application;
FIG. 3 is a schematic diagram of a quantum circuit of a first qubit that may cross-talk with other control lines according to an embodiment of the present application;
FIG. 4 is a schematic diagram of a quantum circuit for modifying a second x-ray structure to prevent crosstalk according to an embodiment of the present application;
FIG. 5 is a schematic diagram of a link from a normal temperature signal source to a qubit according to an embodiment of the present application;
fig. 6 is a schematic diagram of a quantum chip and a package according to an embodiment of the present application;
fig. 7 is a schematic diagram of 4 bonding modes of a first layer bonding pad of a quantum chip according to an embodiment of the present application;
fig. 8 is a schematic diagram of 4 bonding modes of a second layer bonding pad of a quantum chip according to an embodiment of the present application.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application, and the described embodiments are some embodiments of the present application, but not all embodiments of the present application. The components of the embodiments of the present application generally described in the figures herein may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the application, as presented in the figures, is not intended to limit the scope of the application, as claimed, but is merely representative of selected embodiments of the application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application. The following embodiments and features of the embodiments may be combined with each other without conflict.
In the description of the present application, it should be noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.
In order to reduce the actual measurement flow of the very low temperature experiment, and to determine whether some parameters in a quantum circuit have performance problems at low cost, an embodiment of the present application provides a method for determining the performance of a quantum circuit, as shown in fig. 1, including:
step A, obtaining a low-temperature actually-measured performance result of each quantum circuit of a group of quantum circuits; the group of quantum circuits comprises a plurality of quantum circuits with different characteristic parameters;
step B, performing program simulation according to characteristic parameters of each quantum circuit of the group of quantum circuits to obtain a simulation value of each quantum circuit;
step C, according to the comparison between the low-temperature actually measured performance result of each quantum circuit and the simulation value of each quantum circuit, determining a simulation value from the simulation values of each quantum circuit as a characteristic value;
step D, determining the performance of the newly designed quantum circuit according to the relative magnitude relation between the to-be-evaluated simulation value and the characteristic value of the newly designed quantum circuit; the simulation value to be evaluated is obtained by performing program simulation on the characteristic parameters of the newly designed quantum circuit.
According to the quantum circuit performance determining method, the characteristic value of the quantum circuit is obtained, and when a quantum circuit is newly designed, the performance of the newly designed quantum circuit can be determined by only comparing the relative magnitude relation between the characteristic parameter and the characteristic value of the quantum circuit (the determined performance can refer to the degree of qualification and disqualification or quantization quality). The quantum circuit with new design is not required to be put into a low-temperature environment for actual measurement, the actual measurement cost is saved, and the research and development efficiency is improved, so that the method has the beneficial effects.
It should be noted that, in the present application, the description of the steps does not have a limitation of the precedence relationship, and under the condition of no contradiction, the precedence relationship of the steps may be flexibly set, for example, the step a and the step B may be executed first, then the step B may be executed, or the step B may be executed first, then the step a may be executed. The more definite actual measurement result can be obtained by executing the step A and then the step B, for example, the actual measurement result contains a quantum circuit with qualified performance and a quantum circuit with unqualified performance, if the step B is executed firstly and then the step A is executed, the following situations may occur: and (3) finding that the actual measurement performance of the quantum circuits in all the steps B is unqualified in the step A after the step B, and then, carrying out simulation again according to the quantum circuits with qualified actual measurement performance in the step A, and returning to the step B.
Next, an embodiment of the above-described quantum circuit performance determining method will be described taking a specific qubit and its xy line design as an example. In particular, the quantum circuit may further comprise read structures such as read buses and read resonators for reading the qubits, for example control lines (control lines including xy-lines, z-lines) for operating on the qubits implemented on the basis of josephson junctions.
The xy line is abbreviated as x line in the present application. In a successful design, an x-ray can drive the qubit corresponding to the x-ray; in a failed design, the x-ray cannot drive the qubit to which the x-ray corresponds. I.e. the measured performance at low temperature may be either drivable or not drivable.
When the x-ray is designed, the mutual capacitance value of the capacitance between the x-ray and the quantum bit which the x-ray needs to drive can be referred to, and the mutual capacitance value can be used as an imitation value of the quantum circuit which needs to be emulated.
The mutual capacitance value can be changed by structural parameters such as thickness of x-rays, relative positional relationship with qubits, relative distance, etc. The structural parameters may be taken as characteristic parameters. The x-ray can be translated in the x-ray direction to obtain different positions by controlling variable modes, such as fixing the thickness of the x-ray and fixing the position of the qubit, wherein the x-ray is perpendicular to the qubit, and the only variable is that the x-ray is translated from the initial position to serve as one structural parameter, and the characteristic parameter can be one structural parameter or a plurality of structural parameters.
Referring to fig. 2, a quantum circuit includes a first x-ray 101 and a first qubit 102, and an embodiment of a method for determining performance of the quantum circuit corresponding to such a quantum circuit is described.
The low temperature measured performance results of each quantum circuit include: the first x-ray is capable of driving the first qubit, or the first x-ray is not capable of driving the first qubit; the signal driving the first qubit can be applied to the first x-rays in the quantum circuit one by one in the order that the mutual capacitance value between the first x-rays and the first qubit in the quantum circuit gradually increases so as to find out that the first x-rays can just drive the mutual capacitance value of the first qubit, and the structural parameters of the quantum circuit driven by the signal applied each time and the result of whether the first x-rays in the quantum circuit can drive the first qubit in the quantum circuit are recorded.
Wherein for each quantum circuit, the bit frequency of the first qubit may be determined first, the signal applied by the first x-ray being defined as: the frequency of the signal applied at the first x-ray is equal to the bit frequency. The first qubit of each quantum circuit may also be of the same bit frequency, only the bit frequency of the first qubit of one of the quantum circuits need be measured.
The bit frequency is measured as follows: under the condition that the first x-ray in the quantum circuit can drive the first quantum bit (for example, the distance between the first x-ray and the first quantum bit is close enough, so that the mutual capacitance value between the first x-ray and the first quantum bit is large enough, the condition that the first x-ray can drive the first quantum bit is met), different frequency signals are added to the first x-ray of the quantum circuit, frequency points when frequency resonance is generated are observed, and then the bit frequency is determined through measuring the Raratio oscillation.
After obtaining the bit frequency, performing low-temperature actual measurement on the quantum circuits, for example, 6 quantum circuits are actually measured at the total low temperature, namely a quantum circuit 1, a quantum circuit 2, a quantum circuit 3, a quantum circuit 4, a quantum circuit 5 and a quantum circuit 6, wherein mutual capacitance values of the quantum circuits 1 to 6 are sequentially increased, for example, a first x-ray in the quantum circuit 1 is farthest from a first quantum bit, a first x-ray in the quantum circuit 6 is closest to the first quantum bit, actual measurement results of the quantum circuits 1 to 3 are not driven, and actual measurement results of the quantum circuits 4 to 6 are driven.
The quantum circuit corresponding to the actual measurement process comprises the following steps: program simulation is carried out according to the structural parameters of each quantum circuit of the group of quantum circuits, so as to obtain a mutual capacitance value between a first x-ray and a first quantum bit of each quantum circuit; for example, a mutual capacitance value a1 is obtained in the quantum circuit 1, a mutual capacitance value a2 is obtained in the quantum circuit 2, a mutual capacitance value a3 is obtained in the quantum circuit 3, a mutual capacitance value a4 is obtained in the quantum circuit 4, a mutual capacitance value a5 is obtained in the quantum circuit 5, and a mutual capacitance value a6 is obtained in the quantum circuit 6; a1< a2< a3< a4< a5< a6. The unit may be AlfaraaF, 1aF=10-18F.
After the actual measurement and simulation are performed, the step C comprises: according to the comparison of the low-temperature actually measured performance result of each quantum circuit and the mutual capacitance value of each quantum circuit, determining one mutual capacitance value from the mutual capacitance value of each quantum circuit as a first mutual capacitance value characteristic value; in the above example, the comparison between the measured performance at low temperature of each quantum circuit and the mutual capacitance value of each quantum circuit is as follows:
from a1 to a6, a4 which can be just driven can be selected as a first mutual capacitance value characteristic value.
After the first mutual capacitance value characteristic value is obtained, when a new quantum circuit is designed, the new quantum circuit can be simulated to obtain the mutual capacitance value of the quantum bit and the x-ray driving the new quantum circuit, and then the mutual capacitance value is compared with the first mutual capacitance value characteristic value, so that whether the x-ray can drive the quantum bit can be known, and the step D comprises the following steps: if the mutual capacitance value between the first x-ray of the newly designed quantum circuit and the first qubit is greater than or equal to the first mutual capacitance value characteristic value, determining that the first x-ray of the newly designed quantum circuit can drive the first qubit.
For the first qubit, in addition to the above problem of being driven by the first x-ray, there may be a problem of being crosstalked by other control lines, such as fig. 3, where the second x-ray 103 is above or below the first qubit 102, and the projection of the second x-ray on the plane of the first qubit intersects the first qubit, and the second x-ray may be an x-ray for driving other qubits, but may have a driving effect on the first qubit and generate an influence of crosstalk.
In order to cope with the crosstalk problem, in the quantum circuit performance determining method, the low-temperature actually measured performance result of each quantum circuit comprises: the second x-ray can drive the first qubit or the second x-ray cannot drive the first qubit. The crosstalk can be driven to be formed, so that the low-temperature actual measurement performance result can be crosstalk or non-crosstalk.
The signal driving the first qubit can be applied to the second x-rays in the quantum circuit one by one in the order that the mutual capacitance value between the second x-rays and the first qubit in the quantum circuit gradually increases so as to find out that the second x-rays can just drive the mutual capacitance value of the first qubit, and the structural parameters of the quantum circuit driven by the signal applied each time and the result of whether the second x-rays in the quantum circuit can drive the first qubit in the quantum circuit are recorded.
The quantum circuits are subjected to low-temperature actual measurement, for example, 6 quantum circuits are respectively quantum circuit 11, quantum circuit 12, quantum circuit 13, quantum circuit 14, quantum circuit 15 and quantum circuit 16, wherein the mutual capacitance values of the quantum circuits 11 to 16 are sequentially increased, the mutual capacitance value increase can be the size of an air bridge, for example, the second x-ray in the quantum circuit 11 has the largest air bridge, so that the minimum distance between the second x-ray in the quantum circuit 11 and the first quantum bit is the farthest in all the quantum circuits, and the second x-ray in the quantum circuit 16 has the smallest air bridge, so that the minimum distance between the second x-ray in the quantum circuit 16 and the first quantum bit is the nearest in all the quantum circuits. The actual measurement results of the quantum circuits 11 to 13 are not drivable, and the actual measurement results of the quantum circuits 14 to 16 are drivable.
In the mode of setting the mutual capacitance value of the size of the air bridge, the larger the air bridge is, the smaller the formed mutual capacitance value is, the crosstalk is not generated, but the larger the air bridge is, the process difficulty is increased, so that the minimum size of the air bridge is required to be found, and the maximum mutual capacitance value is correspondingly required to be found. The air bridge size may refer to the length of the air bridge (the height of the air bridge is fixed) or the height of the air bridge (the length of the air bridge is fixed). The use of air strips, indium columns, etc. to replace the air bridge described above to change mutual capacitance is similar. The size of the x-ray in the plane can also be changed, as shown in fig. 4, a bend with a length a and a width b is arranged, and the mutual capacitance value is changed by changing the size of a or b.
The quantum circuit corresponding to the actual measurement process comprises the following steps: program simulation is carried out according to the structural parameters of each quantum circuit of the group of quantum circuits, so as to obtain a mutual capacitance value between a second x-ray and a first quantum bit of each quantum circuit; for example, a mutual capacitance value a11 is obtained in the quantum circuit 11, a mutual capacitance value a12 is obtained in the quantum circuit 12, a mutual capacitance value a13 is obtained in the quantum circuit 13, a mutual capacitance value a14 is obtained in the quantum circuit 14, a mutual capacitance value a15 is obtained in the quantum circuit 15, and a mutual capacitance value a16 is obtained in the quantum circuit 16; a11< a12< a13< a14< a15< a16.
After the actual measurement and simulation are performed, the step C comprises: according to the comparison of the low-temperature actually measured performance result of each quantum circuit and the mutual capacitance value of each quantum circuit, determining one mutual capacitance value from the mutual capacitance value of each quantum circuit as a second mutual capacitance value characteristic value; in the above example, the comparison between the measured performance at low temperature of each quantum circuit and the mutual capacitance value of each quantum circuit is as follows:
from a11 to a16, a13 which can not be driven just can be selected as the second mutual capacitance value characteristic value.
After the second mutual capacitance value characteristic value is obtained, when a new quantum circuit is designed, the new quantum circuit can be simulated to obtain the mutual capacitance value between other control lines and the first quantum bit, and then the mutual capacitance value is compared with the second mutual capacitance value characteristic value, so that whether the control lines can form crosstalk to the quantum bit can be known, and the step D comprises the following steps: and if the mutual capacitance value between the second x-ray of the newly designed quantum circuit and the first quantum bit is larger than or equal to the second mutual capacitance value characteristic value, determining crosstalk between the second x-ray of the newly designed quantum circuit and the first quantum bit.
The above are implementations for performance between a particular qubit and control line, all being examples of x-ray related performance for low temperature operation. In addition, signals used in the control and read operations of the superconducting quantum chip need to be transferred from a source terminal at room temperature to a low-temperature layer in a superconducting state, and a link of the signals may involve a plurality of devices and connection lines between the corresponding devices, which may also be problematic. For example, in an entire signal link of an x-ray transmitted bit, devices are more, insertion loss is large, it is difficult to accurately evaluate the entire link, and how to evaluate whether signals in the link are distorted or not can also avoid that each evaluation needs to perform a low-temperature superconducting test on the link by the quantum circuit performance determining method.
In the method for determining the performance of the quantum circuit of the link, the quantum circuit is a link formed by connecting a plurality of devices, each device has parameters of the device, and each step can be set as follows:
in the step A, the low-temperature actually measured performance result of each quantum circuit comprises: the signals in the link are distorted or the signals in the link are not distorted;
the step B comprises the following steps: performing program simulation according to the working parameters of each quantum circuit in the step A to obtain the parameters of each device of each quantum circuit;
the step C comprises the following steps: according to the comparison of the low-temperature actually measured performance result of each quantum circuit and the parameter of each device of each quantum circuit, specifically, firstly looking at the parameter of one device, finding out one quantum circuit with the maximum value of the parameter of the device and one quantum circuit with the minimum value of the parameter of the device from the quantum circuits with the low-temperature actually measured performance result that the signal in the link is not distorted, and determining the maximum characteristic value and the minimum characteristic value of the parameter of the device by using the two circuits; parameters of other devices are the same;
the step D comprises the following steps: if the parameter of a device of the newly designed quantum circuit is not located between the minimum eigenvalue and the maximum eigenvalue, then it is determined that the device of the quantum circuit has a problem.
The newly designed quantum circuit can find out which device or devices have preset parameters exceeding the interval range formed by the minimum characteristic value and the maximum characteristic value through the performance determining method of the quantum circuit, find out the device with the problem, and pertinently correct the device, so that the x signal of the quantum circuit cannot generate distortion problem. The distortion condition can be observed at each node through ADS simulation software or other circuit simulation software simulation.
Fig. 5 shows an example of a link, where a finite pulse width cosine signal device 211, a periodic cosine signal device 212 and a mixer 213 constitute a signal source 21, which is then connected to a qubit via an attenuator 221, a filter 222, a DC module 223, a connector 224, a PCB 225, a bond wire 226, a coupling capacitor module 23.
Wherein the parameters of the attenuator 221, the filter 222, the DC module 223, such as the resistance, capacitance, inductance, S-parameters, etc. thereof. The maximum critical value and the minimum critical value can be obtained through the step C in the quantum circuit performance determining method, and are respectively used as the maximum characteristic value and the minimum characteristic value to limit the approximate usable range of each device, so that a link meeting the use requirement can be obtained.
The bonding wires 226 may be designed in different bonding manners, and whether a bonding manner generates crosstalk or not may also be obtained by the quantum circuit performance determining method.
Fig. 6 shows an example of a quantum chip 31 and a package box 32 to be bonded, wherein the quantum chip is provided with an inner layer and an outer layer (same layer in height), each layer is provided with a round pad bonding sheet which surrounds a square, the bonding sheet is a small square in the figure, the inner round represented by 311 is called a first layer, and the outer round represented by 312 is called a second layer. The package 32 is also provided with an inner and an outer layer, each layer having a peripheral bonding tab, the periphery of the inner side represented by 321 being referred to as the first layer and the periphery of the outer side represented by 322 being referred to as the second layer. The bonding sheets of the quantum chip and the packaging box are too many, and the bonding sheets of the quantum chip and the bonding sheets of the packaging box are placed in a staggered mode.
Testing the performance of different bonding modes, 4 bonding modes of the bonding sheet of the first layer of the quantum chip (4 bonding modes of the bonding sheets on the upper, lower, left and right sides of the square) can be tested according to the mode of fig. 7, and 4 bonding modes of the bonding sheet of the second layer of the quantum chip can be tested according to the mode of fig. 8.
In the quantum circuit performance determining method, the step A comprises the following steps: the structures of fig. 7 and 8 were subjected to low temperature measurement to obtain low temperature measurement performance results of the 8 bonding methods, and the low temperature measurement performance results were crosstalk or non-crosstalk. In the low temperature measurement performance results, the bonding modes in the upper and right directions are not crosstalk, regardless of fig. 7 or 8.
Next, step B includes: program simulation was performed on the structures of fig. 7 and 8 to obtain crosstalk amounts of various bonds, and the crosstalk amounts were used as simulation values. For example, in fig. 7, the maximum crosstalk amount in the non-crosstalk method can be used as a characteristic value, where the crosstalk amount in the lower bonding method is-20 dB, the crosstalk amount in the left bonding method is-15 dB, the crosstalk amount in the upper bonding method is-35 dB, and the crosstalk amount in the right bonding method is-30 dB. I.e., step C, -30dB is selected as the characteristic value.
In the step D, program simulation is carried out on the newly designed quantum circuit, if the crosstalk amount is larger than 30dB, the performance of the newly designed quantum circuit can be determined to be unqualified, and if the crosstalk amount is smaller than or equal to 30dB, the newly designed quantum circuit is determined to be unqualified.
Based on the above embodiments, the embodiments of the present application provide a computer-readable storage medium in which a computer program or instructions are stored, which when executed by a computer, implement the above-described quantum circuit performance determining method. The embodiment of the application also provides a computer program, which comprises instructions, when the computer program is executed by a computer, the computer program causes the computer to execute the quantum circuit performance determining method.
The above-described embodiments of the apparatus and system are merely illustrative, and some or all of the modules may be selected according to actual needs to achieve the objectives of the present embodiment. Those of ordinary skill in the art will understand and implement the present application without undue burden.
The foregoing is only a preferred embodiment of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions easily contemplated by those skilled in the art within the technical scope of the present application should be covered by the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.
Claims (10)
1. A method of quantum circuit performance determination, comprising:
obtaining a low-temperature actually measured performance result of each quantum circuit of a group of quantum circuits; the group of quantum circuits comprises a plurality of quantum circuits with different characteristic parameters;
program simulation is carried out according to the characteristic parameters of each quantum circuit of the group of quantum circuits, so that a simulation value of each quantum circuit is obtained;
according to the comparison between the low-temperature actually-measured performance result of each quantum circuit and the simulation value of each quantum circuit, determining a simulation value from the simulation value of each quantum circuit as a characteristic value;
determining the performance of the newly designed quantum circuit according to the relative magnitude relation between the to-be-evaluated simulation value and the characteristic value of the newly designed quantum circuit; the simulation value to be evaluated is obtained by performing program simulation on the characteristic parameters of the newly designed quantum circuit.
2. The quantum circuit performance determination method of claim 1, wherein each of the quantum circuits comprises a first x-ray and a first qubit;
the low temperature measured performance results of each quantum circuit include: the first x-ray is capable of driving the first qubit, or the first x-ray is not capable of driving the first qubit;
program simulation is carried out according to the characteristic parameters of each quantum circuit of the group of quantum circuits, and the step of obtaining the simulation value of each quantum circuit comprises the following steps: program simulation is carried out according to the structural parameters of each quantum circuit of the group of quantum circuits, so as to obtain a mutual capacitance value between a first x-ray and a first quantum bit of each quantum circuit;
the step of determining a simulated value from the simulated values of each quantum circuit as a characteristic value based on a comparison of the measured performance result of each quantum circuit at the low temperature with the simulated value of each quantum circuit comprises: determining a mutual capacitance value from the mutual capacitance value of each quantum circuit as a first mutual capacitance value characteristic value according to the comparison of the low-temperature actually measured performance result of each quantum circuit and the mutual capacitance value of each quantum circuit;
according to the relative magnitude relation between the to-be-evaluated simulation value and the characteristic value of the newly designed quantum circuit, the step of determining the performance of the newly designed quantum circuit comprises the following steps: if the mutual capacitance value between the first x-ray of the newly designed quantum circuit and the first quantum bit is larger than or equal to the first mutual capacitance value characteristic value, determining that the first x-ray of the newly designed quantum circuit can drive the first quantum bit.
3. The method of quantum circuit performance determination of claim 2, wherein the step of obtaining a low temperature measured performance result for each quantum circuit of the set of quantum circuits comprises:
and applying signals for driving the first quantum bits to the first x-rays in the quantum circuit one by one in the order that the mutual capacitance value between the first x-rays and the first quantum bits in the quantum circuit is gradually increased so as to find out the mutual capacitance value of the first quantum bits which the first x-rays can just drive, and recording the structural parameters of the quantum circuit which is driven by applying the signals each time and the result of whether the first x-rays in the quantum circuit can drive the first quantum bits in the quantum circuit.
4. The quantum circuit performance determination method of claim 3, wherein prior to the step of applying a signal to the first x-ray in the quantum circuit that drives the first qubit, the quantum circuit performance determination method further comprises:
under the condition that the first x-ray in the quantum circuit can drive the first quantum bit, different frequency signals are added to the first x-ray of the quantum circuit, frequency points when frequency resonance is generated are observed, and then the bit frequency of the first quantum bit of the quantum circuit is determined through measuring the Laratio oscillation.
5. The quantum circuit performance determination method of claim 1, wherein the quantum circuit comprises a first x-ray, a first qubit, and a second x-ray; the projection of the second x-ray on the plane of the first qubit is intersected with the first qubit;
the low temperature measured performance results of each quantum circuit include: the second x-ray can drive the first qubit or the second x-ray cannot drive the first qubit;
program simulation is carried out according to the characteristic parameters of each quantum circuit of the group of quantum circuits, and the step of obtaining the simulation value of each quantum circuit comprises the following steps: program simulation is carried out according to the structural parameters of each quantum circuit of the group of quantum circuits, so as to obtain a mutual capacitance value between a second x-ray and a first quantum bit of each quantum circuit;
the step of determining a simulated value from the simulated values of each quantum circuit as a characteristic value based on a comparison of the measured performance result of each quantum circuit at the low temperature with the simulated value of each quantum circuit comprises: determining a second mutual capacitance value characteristic value according to the comparison between the low-temperature actually measured performance result of each quantum circuit and the mutual capacitance value of each quantum circuit;
according to the relative magnitude relation between the to-be-evaluated simulation value and the characteristic value of the newly designed quantum circuit, the step of determining the performance of the newly designed quantum circuit comprises the following steps: and if the mutual capacitance value between the second x-ray of the newly designed quantum circuit and the first quantum bit is larger than or equal to the second mutual capacitance value characteristic value, determining crosstalk between the second x-ray of the newly designed quantum circuit and the first quantum bit.
6. The method of quantum circuit performance determination of claim 5, wherein the step of obtaining a low temperature measured performance result for each quantum circuit of the set of quantum circuits comprises:
and applying signals for driving the first quantum bits to the second x-rays in the quantum circuit one by one in the order of gradually increasing the mutual capacitance value between the second x-rays and the first quantum bits in the quantum circuit so as to find out the mutual capacitance value of the first quantum bits which can be just driven by the second x-rays, and recording the structural parameters of the quantum circuit which can be driven by the signals and the result of whether the first quantum bits can be driven by the second x-rays in the quantum circuit.
7. The quantum circuit performance determination method of claim 6, wherein the second x-rays in the quantum circuit comprise air bridges, the size of the air bridges of the second x-rays being different for each quantum circuit.
8. The method of claim 1, wherein the quantum circuit is a link of a plurality of devices, each device having parameters of the device;
the low temperature measured performance results of each quantum circuit include: the signals in the link are distorted or the signals in the link are not distorted;
program simulation is carried out according to the characteristic parameters of each quantum circuit of the group of quantum circuits, and the step of obtaining the simulation value of each quantum circuit comprises the following steps: program simulation is carried out according to the working parameters of each quantum circuit, so that parameters of each device of each quantum circuit are obtained;
the step of determining a simulated value from the simulated values of each quantum circuit as a characteristic value based on a comparison of the measured performance result of each quantum circuit at the low temperature with the simulated value of each quantum circuit comprises: determining the maximum characteristic value and the minimum characteristic value of the parameters of each device according to the comparison between the low-temperature actually measured performance result of each quantum circuit and the parameters of each device of each quantum circuit;
according to the relative magnitude relation between the to-be-evaluated simulation value and the characteristic value of the newly designed quantum circuit, the step of determining the performance of the newly designed quantum circuit comprises the following steps: if the parameter of a device of the newly designed quantum circuit is not located between the minimum eigenvalue and the maximum eigenvalue, then it is determined that the device of the quantum circuit has a problem.
9. A computer readable storage medium, characterized in that the computer readable storage medium has stored therein a computer program or instructions which, when executed by a computer, implement the quantum circuit performance determining method of any one of claims 1-8.
10. A computer program, characterized in that it comprises instructions which, when executed by a computer, implement the quantum circuit performance determining method of any one of claims 1-8.
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