Method, apparatus, and related device for determining filters in a superconducting quantum chip

Abstract

The present disclosure provides a method and device for determining filters in a superconducting quantum chip, and related equipment, relating to the technical field of quantum computing, and particularly to the technical field of superconducting quantum chips. The specific implementation scheme is as follows: determining the center frequencies of two band-stop filters based on the center frequency of a quantum bit of the superconducting quantum chip; determining the lengths of the two band-stop filters based on the center frequencies of the two band-stop filters; and determining the line segment length of a target line segment of a readout line between the two band-stop filters as the distance between the two band-stop filters based on the operating frequency range of the quantum bit; wherein the two band-stop filters are connected to the readout line, and the readout line between the two band-stop filters is coupled to a readout cavity so that the two band-stop filters are distributed on both sides of the readout cavity. In the present disclosure, based on the center frequency of the quantum bit, the key parameters of the band-stop filter can be designed to improve the decoherence time of the quantum bit, and the entire process design is simple and easy to implement.

Description

Technical Field

[0001] This disclosure relates to the field of quantum computing technology, and more particularly to the field of superconducting quantum chip technology. Background Technology

[0002] A complete superconducting quantum chip needs to include multiple functional modules, such as a readout module, a wiring module, and a qubit and coupling module. Among these modules, the readout module is the first functional module involved in the actual measurement process, so its design is crucial.

[0003] When a qubit transitions from a high energy level to a low energy level, the coupling between the qubit and the readout cavity allows the transitioning photon to potentially enter the readout cavity, thus putting it in an excited state. Furthermore, because the readout cavity is directly coupled to external losses (excitation), the excited state also has a chance to transition back to the ground state, thus leaking the qubit's energy. Therefore, filters need to be designed to reduce energy leakage from the qubit and improve its decoherence time. Summary of the Invention

[0004] This disclosure provides a method, apparatus, and related equipment for determining filters in a superconducting quantum chip.

[0005] According to one aspect of this disclosure, a method for determining a filter in a superconducting quantum chip is provided, comprising:

[0006] The center frequency of the qubits in the superconducting quantum chip determines the center frequency of two band-stop filters; the readout module of the superconducting quantum chip includes a readout cavity and a readout line, with two band-stop filters integrated on the readout line. The readout cavity is coupled to the qubits so that the readout module can obtain the state of the qubits based on the readout cavity and the readout line; the two band-stop filters are used to shield the operating frequency of the qubits.

[0007] Determine the lengths of the two band-stop filters based on their center frequencies; and...

[0008] Based on the operating frequency range of the qubit, the length of the target line segment of the readout line between the two band-stop filters is determined as the distance between the two band-stop filters; wherein, the two band-stop filters are connected to the readout line, and the readout line between the two band-stop filters is coupled to the readout cavity so that the two band-stop filters are distributed on both sides of the readout cavity.

[0009] According to another aspect of this disclosure, an apparatus for determining a filter in a superconducting quantum chip is provided, comprising:

[0010] The frequency determination module is used to determine the center frequencies of two band-stop filters based on the center frequency of the qubits in the superconducting quantum chip; the readout module of the superconducting quantum chip includes a readout cavity and a readout line, with two band-stop filters integrated on the readout line. The readout cavity is coupled to the qubits so that the readout module can obtain the state of the qubits based on the readout cavity and the readout line; the two band-stop filters are used to shield the operating frequency of the qubits.

[0011] A length determination module is used to determine the lengths of two band-stop filters based on their center frequencies; and,

[0012] The distance determination module is used to determine the length of the target line segment of the readout line between two band-stop filters as the distance between the two band-stop filters, based on the operating frequency range of the qubits. The two band-stop filters are connected to the readout line, and the readout line between the two band-stop filters is coupled to the readout cavity so that the two band-stop filters are distributed on both sides of the readout cavity.

[0013] According to another aspect of this disclosure, a superconducting quantum chip is provided, including two band-stop filters designed by the method of any embodiment of this disclosure.

[0014] According to another aspect of this disclosure, an electronic device is provided, comprising:

[0015] At least one processor; and

[0016] The memory is communicatively connected to the at least one processor; wherein,

[0017] The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to perform the methods of any embodiment of the present disclosure.

[0018] According to another aspect of this disclosure, a non-transitory computer-readable storage medium is provided storing computer instructions, wherein the computer instructions are used to cause the computer to perform a method according to any embodiment of this disclosure.

[0019] According to another aspect of this disclosure, a computer program product is provided, including a computer program that, when executed by a processor, implements a method according to any embodiment of this disclosure.

[0020] In this embodiment, the key parameters of the band-stop filter can be designed based on the center frequency of the qubit, including the center frequency of the band-stop filter and the spacing between them, in order to improve the decoherence time of the qubit. The whole process is simple to design and easy to implement, which is of guiding significance for the rapid design of band-stop filters.

[0021] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this disclosure, nor is it intended to limit the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0022] The accompanying drawings are provided to better understand this solution and do not constitute a limitation of this disclosure. Wherein:

[0023] Figure 1a This is a schematic diagram of a bandpass filter according to an embodiment of the present disclosure;

[0024] Figure 1b This is a schematic diagram of an independent filter according to an embodiment of the present disclosure;

[0025] Figure 1c This is a schematic diagram of the structural framework of a band-stop filter according to an embodiment of the present disclosure;

[0026] Figure 2 This is a flowchart illustrating a method for determining a filter in a superconducting quantum chip according to an embodiment of the present disclosure;

[0027] Figure 3 This is a schematic diagram of the geometric configuration of a filter in a superconducting quantum chip according to an embodiment of the present disclosure;

[0028] Figure 4 This is an overall flowchart of a method for determining a filter in a superconducting quantum chip according to an embodiment of the present disclosure;

[0029] Figure 5a This is a schematic diagram of an initial design layout according to an embodiment of the present disclosure;

[0030] Figure 5b This is another schematic diagram of the initial design layout according to an embodiment of the present disclosure;

[0031] Figure 5c This is a schematic diagram of a bridge erection according to one embodiment of the present disclosure;

[0032] Figure 6 This is a schematic diagram of simulation results according to one embodiment of the present disclosure;

[0033] Figure 7a This is a schematic diagram of a target design layout according to an embodiment of the present disclosure;

[0034] Figure 7b This is another schematic diagram of simulation results according to one embodiment of the present disclosure;

[0035] Figure 8 This is a schematic diagram of the structure of a device for determining a filter in a superconducting quantum chip according to an embodiment of the present disclosure;

[0036] Figure 9 This is a block diagram of an electronic device used to implement the method for determining filters in a superconducting quantum chip according to embodiments of the present disclosure. Detailed Implementation

[0037] The exemplary embodiments of this disclosure are described below with reference to the accompanying drawings, including various details of the embodiments to aid understanding, and should be considered merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope of this disclosure. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0038] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this disclosure, "multiple" means two or more, unless otherwise explicitly specified.

[0039] In fields such as cryptography, chemical simulation, and optimization problems, quantum computing utilizes the principles of quantum mechanics to perform certain types of computations, making it more efficient than traditional computers. Unlike the binary bits used in traditional computers, quantum computers use qubits. According to the principle of superposition in quantum mechanics, the state of a qubit can be composed of multiple states simultaneously, therefore parallel computing is a default property of quantum computing.

[0040] To verify the enormous potential and superiority of quantum computing, the hardware infrastructure for quantum computers is inevitably needed, and the physical realization of quantum chips is particularly important. After decades of development, the main physical realization methods for quantum chips currently include ion traps, photons, quantum dots, and superconducting circuits. Among these physically feasible methods, superconducting circuits are relatively easier to expand and integrate, and because the corresponding micro-nano fabrication technology is also relatively mature, they are considered "the most likely solution to be the first to realize practical quantum technology."

[0041] A complete superconducting quantum chip needs to include multiple functional modules, such as a readout module, a wiring module, and a qubit and coupling module. Among these modules, the readout module is the first functional module involved in the actual measurement process, so its design is crucial.

[0042] Measurement is an essential step when obtaining results from operations performed on a quantum computer. The initial concept for the readout module was to directly couple the readout line, which is directly connected to the detector, to the qubit via a capacitor, thereby reading out the information it contains. However, implementing this would cause the qubit to decohere rapidly, hindering quantum gate operations. Therefore, a resonant cavity, also called a readout cavity, is typically placed between the qubit and the readout line. The state of the qubit is read indirectly through the readout cavity to achieve non-destructive measurement. This also improves the decoherence time of the qubit, and this approach is commonly used in the industry.

[0043] For schemes that only add a readout cavity, the coupling state between it and the qubit can be easily calculated under the dispersion limit. When the qubit jumps from a higher energy level to a lower energy level, due to the coupling between the qubit and the readout cavity, the transition photon has a certain probability of entering the readout cavity, thus putting the readout cavity into an excited state. Because the readout cavity is directly coupled to external losses (excitation), the readout cavity in the excited state also has a certain probability of transitioning to the ground state, thereby leaking the energy of the qubit. This process is called the Purcell effect, which is the main factor affecting the decoherence time of the qubit.

[0044] Currently, one approach to suppressing the Purcell effect is to integrate filters into the chip. Known filter solutions include bandpass filters, stand-alone filters, and bandstop filters. Industry research has shown that integrating bandpass filters reduces usable space. Integrating the bandpass filter with the readout line can save space even better, but developing and calibrating a high-quality bandpass filter requires significant costs. Figure 1a As shown, 101 is the qubit, 102 is the readout cavity, 103 is the filter, and Ck and Cg are coupling capacitors. The upper right corner shows the equivalent circuit of the integrated bandpass filter and readout line scheme, where q is the qubit, r is the readout cavity, and F is the readout line.

[0045] Independent filters would occupy more space. Figure 1b The scheme of independent filters is shown. In this scheme, 110 is a qubit, 120 is a readout cavity, 130 is a filter, and 140 is a readout line.

[0046] Given that small bandpass filters are expensive, and stand-alone filters require significant space, integrating a bandstop filter with the readout line is a cost-effective and space-saving solution.

[0047] like Figure 1cAs shown, a possible structural framework for a band-stop filter is presented. However, although some theoretical research has been conducted, designing a band-stop filter that meets the requirements quickly remains a challenge.

[0048] Currently, there is no standardized and rapid integrated band-stop filter design and bandwidth expansion process available in the industry. Therefore, this disclosure provides a design scheme for an integrated band-stop filter integrated onto a readout line. In this embodiment, the band-stop filter, as the name suggests, filters out the input signal within a certain frequency range. By placing the qubit operating frequency at the center frequency of the band-stop filter, it exhibits good suppression of the Purcell effect.

[0049] To facilitate understanding, before introducing the embodiments of this disclosure, a brief overview of the necessity of the readout module and on-chip filter in a superconducting quantum chip is provided. This aims to illustrate the advantages that the embodiments of this disclosure bring to the performance of the superconducting quantum chip, as well as the basic principles of the solutions provided by the embodiments of this disclosure. The following will introduce three aspects: the structure and function of a general readout module, the mechanism and suppression of the Purcell effect, and coplanar waveguide theory.

[0050] 1. The structure and function of a typical reading module

[0051] Generally, a readout module includes at least two components: a readout cavity and a readout line. In a superconducting quantum chip, the readout cavity is directly coupled to the qubit, thus their states are entangled. When the frequency difference (Δ) between the readout cavity and the qubit satisfies the dispersion limit, i.e., Δ >> g, their entangled state can be approximated in a simpler form, where g is the coupling strength between the readout cavity and the qubit.

[0052] The dispersion-limited readout commonly used in the industry is also achieved under the dispersion limit. This is because the coupling between the readout cavity and the qubit under the dispersion limit will cause a certain frequency shift in the readout cavity. This shift is approximately equal to , and this shift is related to the state of the qubit. Therefore, by detecting the resonant frequency of the readout cavity, the state of the qubit can be measured.

[0053] 2. Mechanism and inhibition of the Purcell effect

[0054] In the quantum realm, the decoherence time of a qubit is one of the key indicators of the quality of a quantum chip. Only when the decoherence time of a qubit is sufficiently long relative to the gate operation time can various complex algorithms be implemented on a quantum chip. Therefore, improving the decoherence time of a qubit is of great theoretical and practical significance.

[0055] In the discussion of the readout module, the coupling between the readout cavity and the qubit was mentioned. However, in reality, the readout cavity is also directly coupled to the readout line, which is directly connected to the external loss (signal source). This provides a decoherence channel for the qubit, which in turn causes the Purcell effect.

[0056] In this embodiment, a semi-quantitative (theoretical) explanation of the Purcell effect is given. Under the dispersion limit, when the qubit and the readout cavity are in a steady state, the state function of the system is shown in equation (1):

[0057]

[0058] Where |0> represents the ground state of the readout cavity, |1> represents the first excited state of the readout cavity, and |±> represents the high and low energy levels of the qubit. The meanings of g and Δ are similar to those described above, where Δ is the frequency difference between the readout cavity and the qubit, and g is the coupling strength between the readout cavity and the qubit.

[0059] Because the readout cavity is coupled to the external dissipation, there is a certain probability that the readout cavity will change from the first excited state to the ground state, thereby escaping photons and causing energy loss in the system. Therefore, a dissipation rate can be estimated, as shown in equation (2):

[0060]

[0061] Where a is the annihilation operator corresponding to the read cavity, κ r It is the dissipation width of the read cavity, and also a function of frequency. The meanings of g and Δ are similar to those mentioned above. Equation (2) is the energy dissipation rate of the qubit caused by the Purcell effect.

[0062] In the case of direct coupling between the read cavity and the read line, κ r Frequency is independent. When a filter is added between the read cavity and the read line, the dissipation from the external environment is different at different frequencies due to the modulation effect of the filter in the frequency domain. Therefore, the κ at different frequencies... r They are different.

[0063] Therefore, to improve the decoherence time of a qubit, it is necessary to suppress the Purcell effect, which requires introducing filters into the quantum chip to ensure that the κ value near the operating frequency of the qubit is within acceptable limits. r Decrease.

[0064] 3. Coplanar waveguide theory

[0065] In the design of quantum chips, coplanar waveguides (CPWs) are commonly used to fabricate resonant circuits. Both half-wavelength and quarter-wavelength resonant cavities can achieve certain resonant modes. The fundamental frequency relationship of a half-wavelength resonant cavity is shown in equation (3), and the fundamental frequency relationship of a quarter-wavelength resonant cavity is shown in equation (4).

[0066]

[0067]

[0068] Where c is the speed of light, and l is the geometric length of the resonant cavity, which in this embodiment can be understood as the length of the band-stop filter. eff It is the equivalent dielectric constant.

[0069] ∈ eff The calculation method is shown in equation (5):

[0070] ∈ eff ≈(∈ r +1) / 2 (5)

[0071] Where, ∈ r The relative permittivity of the substrate can be determined based on the substrate actually used, and this disclosure does not limit this.

[0072] While achieving the same resonant frequency, the length of a quarter-wavelength resonant cavity is half that of a half-wavelength resonant cavity, hence the quarter-wavelength resonant cavity is more widely used in this field.

[0073] In view of this, embodiments of this disclosure propose a method for determining filters in a superconducting quantum chip, such as... Figure 2 As shown, it includes:

[0074] S201, the center frequency of two band-stop filters is determined based on the center frequency of the qubits of the superconducting quantum chip.

[0075] The readout module of the superconducting quantum chip includes a readout cavity and a readout line. Two band-stop filters are integrated on the readout line. The readout cavity is coupled to the qubit so that the readout module can obtain the state of the qubit based on the readout cavity and the readout line. The two band-stop filters are used to shield the operating frequency of the qubit.

[0076] S202 determines the lengths of the two band-stop filters based on their center frequencies.

[0077] S203, based on the operating frequency range of the qubit, determines the length of the target line segment of the readout line between the two band-stop filters as the distance between the two band-stop filters; wherein, the two band-stop filters are connected to the readout line, and the readout line between the two band-stop filters is coupled to the readout cavity so that the two band-stop filters are distributed on both sides of the readout cavity.

[0078] It should be noted that the execution order of S202 and S203 is not restricted.

[0079] The geometric configuration is as follows Figure 3 As shown, the two vertical rectangles represent two band-stop filters, and the lines between the two band-stop filters are the readout lines between them.

[0080] In this embodiment, the center frequencies of two band-stop filters are determined based on the center frequencies of the qubits in the superconducting quantum chip. This allows the band-stop filters to filter out signals near the center frequencies of the qubits, thereby improving the decoherence time of the qubits. In this embodiment, the key parameters of the band-stop filters, including their center frequencies and the spacing between them, can be designed based on the center frequencies of the qubits. The entire process is simple to design and easy to implement, providing guidance for the rapid design of band-stop filters.

[0081] In this embodiment, the process for determining the filter in the superconducting quantum chip can be divided into three stages: determining the initial design layout, adjusting and iterating relevant parameters, and verifying performance parameters. Each stage is described in detail below:

[0082] 1. Determine the initial design layout

[0083] During implementation, determining the initial design layout can be divided into determining the center frequencies of the two band-stop filters, determining the lengths of the band-stop filters, and determining the length of the target line segment between the two band-stop filters (i.e., the spacing between the two band-stop filters). The following details how to determine these three parameters:

[0084] a) Determine the center frequencies of the two bandstop filters.

[0085] Band-stop filters can filter out input signals within a certain frequency range. Based on the Purcell effect, the band-stop filter will function effectively when its center frequency roughly coincides with the center frequency of the qubit. Therefore, determining the center frequencies of two band-stop filters based on the center frequency of the qubit in a superconducting quantum chip can be implemented by selecting the center frequencies of the two band-stop filters within a preset range based on the qubit's center frequency.

[0086] This preset range is used to make the center frequency of the band-stop filter as close as possible to the center frequency of the quantum bit.

[0087] In some embodiments, such as when the center frequency of the superconducting quantum bit needs to be less than 5 GHz, in order to satisfy the dispersion coupling condition, the frequency of the readout cavity needs to have a certain frequency difference with the quantum bit, generally greater than 1 GHz, so the frequency of the readout cavity needs to be greater than 6 GHz.

[0088] For example, the center frequency of the superconducting quantum bit can be chosen to be 4.5 GHz, while the cavity frequency of the readout cavity is approximately 7 GHz. Therefore, the center frequencies of the two band-stop filters can be determined to be approximately 4.5 GHz.

[0089] In this embodiment of the present disclosure, within a preset range based on the center frequency of the qubit, the center frequencies of two band-stop filters are selected so that the band-stop filters can filter signals within the operating frequency of the qubit, thereby improving the decoherence time of the qubit.

[0090] b) Determine the length of the band-stop filter

[0091] In some embodiments, the lengths of the two band-stop filters are determined based on their center frequencies. This can be implemented by determining the lengths of the two band-stop filters based on coplanar waveguide theory and their center frequencies.

[0092] In practice, since quarter-wavelength resonant cavities are widely used in this field, taking a quarter-wavelength resonant cavity as an example, the calculation method for the length of the band-stop filter is derived using equation (4), as shown in equation (6):

[0093]

[0094] Where f1 is the center frequency of the band-stop filter, and the meanings of other parameters are similar to those in equation (4). This embodiment does not limit them one by one.

[0095] In this embodiment, the lengths of the two band-stop filters are determined using coplanar waveguide theory. This method uses fewer parameters and can easily and accurately design the lengths of the band-stop filters so that they meet the corresponding performance requirements and improve the decoherence time of the qubits.

[0096] c) The length of the target line segment between the two band-stop filters

[0097] In superconducting quantum circuits, the operating frequency range of qubits is generally 3 to 8 GHz. Therefore, other noise caused by other resonant modes needs to be shifted out of this frequency range to ensure that the band-stop filter works effectively.

[0098] Since the target line segment can be equivalent to a half-wavelength resonant cavity, the length of the target line segment between the two band-stop filters can be determined based on the operating frequency range of the qubit. This can be implemented as follows: Based on coplanar waveguide theory and the operating frequency range of the qubit, the length of the target line segment between the two band-stop filters is determined so that the center frequency of the half-wavelength resonant cavity equivalent to the target line segment is outside the operating frequency range of the qubit.

[0099] Since the target line segment is equivalent to a half-wavelength resonant cavity, expression (7) can be derived using equation (3):

[0100]

[0101] In equation (7), l0 represents the length of the target line segment between the two band-stop filters, f2 represents the operating frequency of the quantum bit, and the other parameters have similar meanings to those in equation (6). This embodiment will not elaborate on these parameters further.

[0102] In this embodiment of the disclosure, the length of the target line segment of the readout line between two band-stop filters is determined using coplanar waveguide theory. This allows for a simple and accurate design of the spacing between the two band-stop filters, thereby improving the decoherence time of the qubit.

[0103] Because the filter is directly connected to the read line, the electromagnetic environment at the node is complex, causing current to escape to the ground planes at both ends, resulting in a difference in ground potential. To solve this problem, an air bridge can be installed at the connection point between the two band-stop filters and the read line in the initial design layout.

[0104] In this embodiment, an air bridge is installed at the connection between the two band-stop filters and the readout line to eliminate the influence of potential difference and improve the working efficiency of the band-stop filters.

[0105] 2. Adjust and iterate the relevant parameters.

[0106] To further improve filter performance through iterative optimization, this embodiment requires simulation of the initial design layout to obtain a target design layout that meets preset conditions. These preset conditions are: no spurious frequencies within the operating frequency range of the qubits and the center frequencies of the two band-stop filters are within the operating frequency range of the qubits. Specifically, this can be implemented as follows:

[0107] Step A1: Based on the length of the target line segment between the two band-stop filters and the length of the two band-stop filters, determine the initial design layout of the two integrated band-stop filters on the read line.

[0108] Step A2: Simulate the initial design layout and obtain the simulation results;

[0109] Step A3: If the simulation results meet the preset conditions, the initial design layout is determined as the target design layout of the integrated bandstop filter.

[0110] Among them, noise frequency refers to the signal generated by the components inside the readout module that falls within the operating frequency range of the quantum bit and the readout cavity.

[0111] With no spurious frequencies within the operating frequency range of the qubits and the center frequencies of the two band-stop filters falling within the operating frequency range of the qubits, the simulation results meet the preset conditions, allowing the initial design layout to be determined as the target design layout for the integrated band-stop filter.

[0112] In this embodiment, only the length of the target line segment between the two band-stop filters and the length of the two band-stop filters are needed to determine the initial design layout of the two integrated band-stop filters on the read line. Then, programmed simulation verification and iteration are performed to finally obtain the target design layout that meets the preset conditions. The design process based on the target design layout obtained in this way is simple and easy to implement, allowing for the quick and easy design of the required band-stop filters.

[0113] In another embodiment, if the simulation results do not meet the preset conditions, the parameters of the two band-stop filters in the initial design layout can be adjusted to obtain a design layout that meets the conditions. This can be implemented as follows:

[0114] Step B1: Based on the problem categories in the simulation results, adjust the parameters of the two band-stop filters in the initial design layout.

[0115] The problem categories include spurious frequencies generated within the operating frequency range of the qubits and a frequency difference between the simulated frequency and the center frequency of the two band-stop filters that is greater than a preset frequency difference. The iterative optimization methods for these two problem categories are described in detail below:

[0116] Problem Category 1) Generation of spurious frequencies within the operating frequency range of qubits

[0117] In some embodiments, when the problem category in the simulation results is noise generation within the operating frequency range of the qubit, the length of the target line segment between the two band-stop filters is adjusted to eliminate the noise.

[0118] In this embodiment of the disclosure, noise frequencies within the operating frequency of the qubit are eliminated to ensure the accuracy of the band-stop filter and improve the decoherence time of the qubit.

[0119] Specifically, the method for eliminating noise frequencies can be implemented as follows: when the frequency of the noise frequency is higher than the first frequency threshold, reduce the length of the target line segment; when the frequency of the noise frequency is lower than the second frequency threshold, increase the length of the target line segment; the second frequency threshold is less than the first frequency threshold.

[0120] The first frequency threshold and the second frequency threshold are defined based on the operating frequency range of the qubit. The first frequency threshold is lower than the upper limit of the operating frequency range of the qubit, and the second frequency threshold is higher than the lower limit of the operating frequency range of the qubit.

[0121] Since the operating frequency range of qubits is generally 3 to 8 GHz, when the noise frequency is around 8 GHz, for example, when the noise frequency is around 7 GHz, the length of the target line segment is adaptively reduced; when the noise frequency is around 3 GHz, for example, when the noise frequency is around 4 GHz, the length of the target line segment is adaptively increased.

[0122] In practice, taking the reduction of the target line segment length as an example, the target line segment can be reduced by a first specified step size. The frequency change of the noise frequency can then be verified through further simulation experiments. When the noise frequency shifts out of the operating frequency range of the qubit, the length of the target line segment is obtained. If the noise frequency does not shift out of the operating frequency range of the qubit, the length of the target line segment can be further reduced.

[0123] In practice, taking increasing the length of the target line segment as an example, the target line segment can be increased by a second specified step size first. The frequency change of the noise frequency can then be verified through further simulation experiments. The length of the target line segment is obtained when the noise frequency shifts out of the operating frequency range of the qubit. If the noise frequency does not shift out of the operating frequency range of the qubit, the length of the target line segment can be increased further.

[0124] It should be noted that the first specified step size and the second specified step size can be determined based on the actual situation, and this disclosure does not limit them.

[0125] In this embodiment of the disclosure, the length of the target line segment is adaptively adjusted based on the simulation results. This adjustment method is simple to implement, easy to operate, and can quickly iteratively optimize the filter to meet the corresponding performance requirements, thereby improving the decoherence time of the quantum bit.

[0126] Problem Category 2) The frequency difference between the simulated frequency and the center frequency of the two band-stop filters is greater than the preset frequency difference.

[0127] To achieve a simulation frequency close to the center frequency of the two band-stop filters, their frequency difference needs to be as small as possible. Therefore, when the simulation results indicate a problem where the frequency difference between the simulation frequency and the center frequency of the two band-stop filters is greater than a preset frequency difference, the lengths of the two band-stop filters should be adjusted to make the frequency difference less than the preset frequency difference.

[0128] The preset frequency difference is used to make the simulated frequencies of the two band-stop filters as close as possible to the center frequencies of the two band-stop filters.

[0129] In this embodiment, the simulation frequencies of the two band-stop filters are made as close as possible to the center frequencies of the two band-stop filters, so that the band-stop filters can shield the operating frequency of the qubits. This method can quickly design the lengths of the two band-stop filters to improve the decoherence time of the qubits.

[0130] The specific adjustment method can be implemented as follows: if the simulated frequency of the two band-stop filters is less than the center frequency of the two band-stop filters, reduce the length of the two band-stop filters so that the frequency difference is less than the preset frequency difference; if the simulated frequency of the two band-stop filters is greater than the center frequency of the two band-stop filters, increase the length of the two band-stop filters so that the frequency difference is less than the preset frequency difference.

[0131] In practice, taking an example where the simulated frequency of the two band-stop filters is less than their center frequency, the lengths of the two band-stop filters can be reduced by a third specified step. A second simulation can then be conducted to verify the frequency change of the simulated frequency of the two band-stop filters. If the frequency difference between the simulated frequency and the center frequency is less than the preset frequency difference, the lengths of the two band-stop filters are obtained. If the frequency difference between the simulated frequency and the center frequency is still greater than the preset frequency difference, the lengths of the two band-stop filters are further reduced.

[0132] In practice, taking an example where the simulated frequency of the two band-stop filters is greater than their center frequency, the lengths of the two band-stop filters can be increased by a fourth specified step. A second simulation can then be conducted to verify the frequency change of the simulated frequency of the two band-stop filters. If the frequency difference between the simulated frequency and the center frequency is less than the preset frequency difference, the lengths of the two band-stop filters are obtained. If the frequency difference between the simulated frequency and the center frequency is still greater than the preset frequency difference, the lengths of the two band-stop filters are further increased.

[0133] It should be noted that the third and fourth specified step sizes can be determined based on actual circumstances, and this disclosure does not limit them.

[0134] In this embodiment, the length of the band-stop filter is adaptively adjusted based on simulation results to make the frequency difference less than a preset frequency difference, so that the band-stop filter can shield the operating frequency of the qubit. This method can quickly iteratively optimize the lengths of the two band-stop filters to improve the decoherence time of the qubit. This adjustment method is simple to implement and easy to operate.

[0135] Step B2: Perform simulation verification based on the adjusted initial design layout until the final simulation results meet the preset conditions.

[0136] In this embodiment of the disclosure, considering the possible types of problems, different solutions are given based on the corresponding problem types, and the solutions are adjusted and then simulated again to obtain simulation results. Based on multiple iterations, the performance of the band-stop filter is improved.

[0137] 3. Performance parameter verification

[0138] In some embodiments, based on the obtained target design layout, at least one additional electromagnetic simulation verification is performed on the target design layout to obtain the verification result; if the verification result meets the preset conditions, the target design layout is determined as the final design layout of the integrated bandstop filter.

[0139] In some embodiments, taking two simulations as an example, if the result of the second simulation does not meet the preset conditions, adjustments can be made based on steps B1-B2 to make the result of the second simulation meet the preset conditions.

[0140] In this embodiment of the disclosure, multiple simulations are used to ensure the reliability and accuracy of the target design layout.

[0141] For ease of understanding, this disclosure also provides an overall flowchart of a method for determining filters in a superconducting quantum chip, as shown below. Figure 4 As shown, it can be implemented as follows:

[0142] S401, the center frequency of two band-stop filters is determined based on the center frequency of the qubits of the superconducting quantum chip.

[0143] S402, based on coplanar waveguide theory and the center frequencies of the two band-stop filters, determine the lengths of the two band-stop filters; and based on coplanar waveguide theory and the operating frequency range of the qubit, determine the length of the target line segment of the readout line between the two band-stop filters.

[0144] S403, based on the length of the target line segment between the two band-stop filters and the length of the two band-stop filters, determines the initial design layout of the two integrated band-stop filters on the read line and performs bridging.

[0145] S404 simulates the initial design layout and obtains the first simulation result.

[0146] S405, determine whether the first simulation result meets the preset conditions; if the preset conditions are met, execute S406; if the preset conditions are not met, execute S407.

[0147] The preset condition is that there are no spurious frequencies within the operating frequency range of the quantum bit and the center frequencies of the two band-stop filters are within the operating frequency range of the quantum bit.

[0148] S406, Perform a second simulation on the initial design layout and determine whether the second simulation result meets the preset conditions; if the preset conditions are met, proceed to S408; if the preset conditions are not met, proceed to S407.

[0149] S407, based on the problem category, adjusts the parameters of the two band-stop filters in the initial design layout.

[0150] Among these issues, the problem categories include the generation of noise within the operating frequency range of the qubit and the frequency difference between the simulated frequency of the two band-stop filters and the center frequency of the two band-stop filters being greater than the preset frequency difference.

[0151] In the case where the problem category in the simulation results is the generation of noise within the operating frequency range of the qubit, the length of the target line segment between the two band-stop filters is adjusted to eliminate the noise.

[0152] In the simulation results, the problem category is that the frequency difference between the simulated frequency of the two band-stop filters and the center frequency of the two band-stop filters is greater than the preset frequency difference. The length of the two band-stop filters is adjusted so that the center frequency of the band-stop filters is close to the center frequency of the quantum bits.

[0153] S408 outputs the design layout.

[0154] Based on the foregoing explanation, the entire process is illustrated with an example to demonstrate the rationality and simplicity of the design process:

[0155] 1. Determine the initial design layout

[0156] Step 1: Determine the center frequency of the band-stop filter

[0157] Taking a scenario where the operating frequency of the superconducting quantum bit is less than 5 GHz, while the frequency of the readout cavity needs to be greater than 6 GHz, we can choose an operating frequency of 4.5 GHz for the superconducting quantum bit and a cavity frequency of approximately 7 GHz for the readout cavity. Therefore, the center frequency of the two band-stop filters can be approximately 4.5 GHz.

[0158] Step 2: Determine the length of the band-stop filter

[0159] Based on coplanar waveguide theory, the length of the band-stop filter can be deduced. Taking sapphire substrate as an example, the relative permittivity of sapphire substrate is 10.85. Based on equation (5), the equivalent permittivity (∈ eff The value can be approximately 5.925. Based on the aforementioned steps, the center frequency of the band-stop filter is approximately 4.5 GHz, and the length (l) of the band-stop filter is 6847 μm based on equation (6).

[0160] Step 3: Length of the target line segment between the two band-stop filters

[0161] In the second step, the length of the band-stop filter was calculated. Now, it is necessary to estimate the length of the target line segment between the two band-stop filters. Generally, the frequency range commonly used in superconducting quantum circuits is 3–8 GHz. Therefore, the noise caused by other resonant modes must be shifted out of this frequency range, and this objective can only be achieved by adjusting the geometric distance l0 between the two sets of filters.

[0162] With the quantum bit operating at a frequency of 8 GHz, the length of the target line segment can be calculated based on equation (7). With the quantum bit operating at a frequency of 3 GHz, the length of another target line segment can be calculated based on equation (7). Since the current size of superconducting quantum chips is on the order of approximately 10 mm, therefore The magnitude is too large; only the geometric distance l0 needs to be less than 1. There will be no more noticeable noise in the commonly used frequency range of the filter. Therefore, the length l0 of the target line segment between the two band-stop filters can be set to 7000 μm.

[0163] Of course, the actual value can be determined based on the actual situation, and this disclosure does not limit it.

[0164] Step 4: Draw the design map and construct the bridge.

[0165] Based on the lengths of the two band-stop filters obtained above and the length of the target line segment between the two band-stop filters, an initial design layout is obtained, as shown below. Figure 5a As shown, the lengths of the two black lines ( Figure 5a (l) represents the lengths of the two band-stop filters, and the length of the gray line is ( Figure 5a In the middle, l0) is the length of the target line segment between the two band-stop filters, which is the part integrated with the readout line. Figure 5bThis is an enlarged view of the connection between the band-stop filter and the read line in the layout. The slot width can be set to 5μm, and the width of the read line and the filter can be 10μm. On a sapphire substrate with a relative permittivity of 10.85, the CPW impedance of this size is approximately 50Ω.

[0166] Of course, the slot width, the width of the readout line, and the width of the filter can be set based on the actual situation, and this disclosure does not limit this.

[0167] During implementation, an air bridge 4μm high can be erected near the connection point, such as... Figure 5c As shown, the gray square frames represent bridge piers, and the dashed rectangular frames spanning the piers represent the bridge deck.

[0168] 2. Adjust and iterate the relevant parameters.

[0169] Step 5: Adjust the length of the target line segment between the two band-stop filters.

[0170] The initial design layout is simulated to obtain simulation results. These results are presented in the form of a power rate curve spectrum, such as... Figure 6 As shown. View Figure 6 If there are no other noise frequencies in the spectrum of the transmission rate curve, it indicates that the length of the target line segment between the two band-stop filters is appropriate, so this step can be omitted.

[0171] Step 6: Adjust the filter geometry length

[0172] Or check Figure 6 The center frequency of the band-stop filter obtained from the simulation is approximately 4.5 GHz, which basically matches the preset conditions, so this step can be omitted.

[0173] 3. Performance parameter verification

[0174] To ensure the correctness of this design, a secondary simulation can be performed on the same layout using another simulation software. The resulting target design layout is as follows: Figure 7a As shown in the diagram. The gray rectangle represents the groove, the horizontal white rectangle represents the readout line, the vertical black rectangle represents a band-stop filter, and the striped rectangle represents the bridging element. The simulation results are as follows. Figure 7b As shown, with Figure 6 The result is similar to that in the previous simulation, which means that the result of the second simulation also meets the preset conditions.

[0175] In summary, this disclosure presents a design flow for an integrated band-stop filter in a superconducting quantum circuit. During the design process, only given design parameters are required; the proposed flow in this disclosure allows for the design, simulation verification, and iteration of the band-stop filter in the superconducting quantum chip, ultimately completing the design. Specifically, the present invention offers the following advantages:

[0176] 1. Simple design: The embodiments of this disclosure only require a few initial parameters, and then an integrated band-stop filter that meets the design requirements can be quickly iterated according to the process of this disclosure.

[0177] 2. Reliable Results: The embodiments disclosed herein take into account possible deviations and will continue to iterate if the preset conditions are not met; at the same time, this design process requires verification through two different simulations. Therefore, the reliability of the results can be guaranteed.

[0178] 3. High practicality: The integrated band-stop filter in this embodiment only requires minor modifications to the readout line and does not have much negative impact on the subsequent large-scale design; for direct readout cavity chip layouts without filters, filter design can be completed with minimal modifications.

[0179] 4. High degree of automation: The process steps of the embodiments of this disclosure are clear and straightforward, and can be coded to design filters with any requirements, which helps to promote the automation of quantum chip design.

[0180] Based on the same technical concept, this disclosure also discloses a superconducting quantum chip, including two band-stop filters designed as described above.

[0181] In this embodiment of the present disclosure, the filter constructed by two sets of band-stop filters can suppress the dissipation of the quantum bit signal, has a good suppression effect on the Purcell effect, and improves the performance of the superconducting quantum chip.

[0182] Based on the same technical concept, this disclosure also discloses a device 800 for determining the filter in a superconducting quantum chip, such as... Figure 8 As shown, it includes:

[0183] The frequency determination module 801 is used to determine the center frequency of two band-stop filters based on the center frequency of the qubits of the superconducting quantum chip; the readout module of the superconducting quantum chip includes a readout cavity and a readout line, the two band-stop filters are integrated on the readout line, and the readout cavity is coupled to the qubits so that the readout module can obtain the state of the qubits based on the readout cavity and the readout line; the two band-stop filters are used to shield the operating frequency of the qubits.

[0184] The length determination module 802 is used to determine the lengths of the two band-stop filters based on their center frequencies; and,

[0185] The distance determination module 803 is used to determine the length of the target line segment of the readout line between two band-stop filters as the distance between the two band-stop filters based on the operating frequency range of the qubit; wherein the two band-stop filters are connected to the readout line, and the readout line between the two band-stop filters is coupled to the readout cavity so that the two band-stop filters are distributed on both sides of the readout cavity.

[0186] In some embodiments, the frequency determination module is configured to:

[0187] Within a preset range based on the center frequency of the qubit, the center frequencies of two band-stop filters are selected.

[0188] In some embodiments, a simulation module is further included, for:

[0189] The first determining unit is used to determine the initial design layout of the two band-stop filters integrated on the read line based on the length of the target line segment between the two band-stop filters and the length of the two band-stop filters.

[0190] The simulation unit is used to simulate the initial design layout and obtain simulation results;

[0191] The second determining unit is used to determine the initial design layout as the target design layout of the integrated bandstop filter when the simulation results meet the preset conditions. The preset conditions are that there are no spurious frequencies in the operating frequency range of the quantum bits and the center frequencies of the two bandstop filters are in the operating frequency range of the quantum bits.

[0192] In some embodiments, an adjustment module is further included, for:

[0193] The adjustment unit is used to adjust the parameters of the two band-stop filters in the initial design layout based on the problem category in the simulation results if the simulation results do not meet the preset conditions.

[0194] The verification unit is used to perform simulation verification based on the adjusted initial design layout until the final simulation results meet the preset conditions.

[0195] In some embodiments, the adjustment unit is configured to:

[0196] In the case where the problem category in the simulation results is the generation of noise within the operating frequency range of the qubit, the length of the target line segment between the two band-stop filters is adjusted to eliminate the noise.

[0197] In some embodiments, the adjustment unit is configured to:

[0198] If the frequency of the noise is higher than the first frequency threshold, reduce the length of the target line segment.

[0199] If the frequency of the noise is lower than the second frequency threshold, increase the length of the target line segment; the second frequency threshold is less than the first frequency threshold.

[0200] In some embodiments, the adjustment unit is configured to:

[0201] In the simulation results, the problem category is that the frequency difference between the simulated frequency of the two band-stop filters and the center frequency of the two band-stop filters is greater than the preset frequency difference. The length of the two band-stop filters is adjusted so that the frequency difference is less than the preset frequency difference.

[0202] In some embodiments, the adjustment unit is configured to:

[0203] If the simulation frequency of the two band-stop filters is less than the center frequency of the two band-stop filters, reduce the length of the two band-stop filters so that the frequency difference is less than the preset frequency difference.

[0204] If the simulation frequency of the two band-stop filters is greater than the center frequency of the two band-stop filters, increase the length of the two band-stop filters so that the frequency difference is less than the preset frequency difference.

[0205] In some embodiments, the length determining module is configured to:

[0206] Based on coplanar waveguide theory and the center frequencies of the two band-stop filters, the lengths of the two band-stop filters are determined.

[0207] In some embodiments, the distance determination module is configured to:

[0208] Based on coplanar waveguide theory and the operating frequency range of qubits, the length of the target line segment between two band-stop filters is determined so that the center frequency of the half-wavelength resonant cavity equivalent to the target line segment is outside the operating frequency range of the qubits.

[0209] In some embodiments, an air bridge is provided at the connection point between the two band-stop filters and the readout line in the initial design layout.

[0210] In some embodiments, a verification module is also included, for:

[0211] Based on the target design layout, at least one additional electromagnetic simulation verification is performed on the target design layout to obtain the verification results;

[0212] If the verification results meet the preset conditions, the target design layout will be determined as the final design layout of the integrated bandstop filter.

[0213] The specific functions and examples of each module, submodule / unit of the apparatus in this disclosure embodiment can be found in the relevant descriptions of the corresponding steps in the above method embodiments, and will not be repeated here.

[0214] According to embodiments of this disclosure, this disclosure also provides an electronic device, a readable storage medium, and a computer program product.

[0215] Figure 9 A schematic block diagram of an example electronic device 900 that can be used to implement embodiments of the present disclosure is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device may also represent various forms of mobile devices, such as personal digital assistants, cellular phones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the present disclosure described and / or claimed herein.

[0216] like Figure 9 As shown, device 900 includes a computing unit 901, which can perform various appropriate actions and processes based on a computer program stored in read-only memory (ROM) 902 or a computer program loaded from storage unit 908 into random access memory (RAM) 903. RAM 903 may also store various programs and data required for the operation of device 900. The computing unit 901, ROM 902, and RAM 903 are interconnected via bus 904. Input / output (I / O) interface 905 is also connected to bus 904.

[0217] Multiple components in device 900 are connected to I / O interface 905, including: input unit 906, such as keyboard, mouse, etc.; output unit 907, such as various types of monitors, speakers, etc.; storage unit 908, such as disk, optical disk, etc.; and communication unit 909, such as network card, modem, wireless transceiver, etc. Communication unit 909 allows device 900 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0218] The computing unit 901 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of the computing unit 901 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various computing units running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. The computing unit 901 performs the various methods and processes described above, such as the method of determining a filter in a superconducting quantum chip. For example, in some embodiments, the method of determining a filter in a superconducting quantum chip may be implemented as a computer software program tangibly contained in a machine-readable medium, such as storage unit 908. In some embodiments, part or all of the computer program may be loaded and / or installed on device 900 via ROM 902 and / or communication unit 909. When the computer program is loaded into RAM 903 and executed by the computing unit 901, one or more steps of the method of determining a filter in a superconducting quantum chip described above may be performed. Alternatively, in other embodiments, computing unit 901 may be configured by any other suitable means (e.g., by means of firmware) to perform a method for determining filters in a superconducting quantum chip.

[0219] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), complex programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0220] Program code used to implement the methods of this disclosure may be written in any combination of one or more programming languages. This program code may be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing apparatus, such that when executed by the processor or controller, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may be executed entirely on a machine, partially on a machine, as a standalone software package partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0221] In the context of this disclosure, a machine-readable medium can be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium can be, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0222] To provide interaction with a user, the systems and techniques described herein can be implemented on a computer having: a display device for displaying information to the user (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor); and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the computer. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0223] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as a data server), or computing systems that include middleware components (e.g., an application server), or computing systems that include frontend components (e.g., a user computer with a graphical user interface or web browser through which a user can interact with embodiments of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., a communication network). Examples of communication networks include local area networks (LANs), wide area networks (WANs), and the Internet.

[0224] Computer systems can include clients and servers. Clients and servers are generally located far apart and typically interact via communication networks. Client-server relationships are created by computer programs running on the respective computers and having a client-server relationship with each other. Servers can be cloud servers, servers in distributed systems, or servers incorporating blockchain technology.

[0225] It should be understood that the various forms of processes shown above can be used to rearrange, add, or delete steps. For example, the steps described in this disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this disclosure can be achieved, and this is not limited herein.

[0226] The specific embodiments described above do not constitute a limitation on the scope of protection of this disclosure. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A method for determining a filter in a superconducting quantum chip, comprising: The center frequencies of two band-stop filters are determined based on the center frequencies of the qubits in the superconducting quantum chip. The readout module of the superconducting quantum chip includes a readout cavity and a readout line. The two band-stop filters are integrated on the readout line. The readout cavity is coupled to the qubit, so that the readout module can obtain the state of the qubit based on the readout cavity and the readout line. The two band-stop filters are used to shield the operating frequency of the qubit. Based on coplanar waveguide theory and the center frequencies of the two band-stop filters, the lengths of the two band-stop filters are determined; and... Based on coplanar waveguide theory and the operating frequency range of the qubit, the length of the target line segment between the two band-stop filters is determined as the distance between the two band-stop filters; the center frequency of the half-wavelength resonant cavity equivalent to the target line segment is outside the operating frequency range of the qubit; wherein, the two band-stop filters are connected to the read line, and the read line between the two band-stop filters is coupled to the read cavity so that the two band-stop filters are distributed on both sides of the read cavity.

2. The method according to claim 1, wherein, The determination of the center frequencies of the two band-stop filters based on the center frequencies of the qubits of the superconducting quantum chip includes: Within a preset range based on the center frequency of the qubit, the center frequencies of the two band-stop filters are selected.

3. The method according to claim 1 or 2, further comprising: Based on the length of the target line segment between the two band-stop filters and the length of the two band-stop filters, the initial design layout for integrating the two band-stop filters on the read line is determined. The initial design layout was simulated to obtain simulation results; If the simulation results meet the preset conditions, the initial design layout will be determined as the target design layout of the integrated bandstop filter. The preset conditions are that there are no spurious frequencies in the operating frequency range of the qubit and the center frequencies of the two bandstop filters are in the operating frequency range of the qubit.

4. The method according to claim 3, further comprising: If the simulation results do not meet the preset conditions, the parameters of the two band-stop filters in the initial design layout are adjusted based on the problem categories in the simulation results. Simulation verification is performed based on the adjusted initial design layout until the final simulation results meet the preset conditions.

5. The method according to claim 4, wherein, The adjustment of the parameters of the two band-stop filters in the initial design layout based on the problem categories in the simulation results includes: If the problem category in the simulation results is that noise is generated within the operating frequency range of the qubit, the length of the target line segment between the two band-stop filters is adjusted to eliminate the noise.

6. The method according to claim 5, wherein, When the problem category in the simulation results is spurious frequencies generated within the operating frequency range of the qubit, adjusting the segment length of the target line segment between the two band-stop filters to eliminate the spurious frequencies includes: If the frequency of the noise frequency is higher than a first frequency threshold, the length of the target line segment is reduced. If the frequency of the noise is lower than the second frequency threshold, the length of the target line segment is increased; the second frequency threshold is less than the first frequency threshold.

7. The method according to claim 4, wherein, The adjustment of the parameters of the two band-stop filters in the initial design layout based on the problem categories in the simulation results includes: If the problem category in the simulation results is that the frequency difference between the simulation frequency of the two band-stop filters and the center frequency of the two band-stop filters is greater than a preset frequency difference, the length of the two band-stop filters shall be adjusted so that the frequency difference is less than the preset frequency difference.

8. The method according to claim 7, wherein, Adjusting the lengths of the two band-stop filters to make the frequency difference less than the preset frequency difference includes: If the simulated frequency of the two band-stop filters is less than the center frequency of the two band-stop filters, the length of the two band-stop filters is reduced so that the frequency difference is less than the preset frequency difference; If the simulated frequency of the two band-stop filters is greater than the center frequency of the two band-stop filters, the length of the two band-stop filters is increased so that the frequency difference is less than the preset frequency difference.

9. The method according to claim 3, wherein an air bridge is provided at the connection between the two band-stop filters and the read line in the initial design layout.

10. The method of claim 3, further comprising: Based on the obtained target design layout, at least one additional electromagnetic simulation verification is performed on the target design layout to obtain the verification results; If the verification results meet the preset conditions, the target design layout is determined as the final design layout of the integrated bandstop filter.

11. A superconducting quantum chip comprising the two band-stop filters designed by the method of any one of claims 1-10.

12. An apparatus for determining a filter in a superconducting quantum chip, comprising: A frequency determination module is used to determine the center frequencies of two band-stop filters based on the center frequencies of the qubits of the superconducting quantum chip; the readout module of the superconducting quantum chip includes a readout cavity and a readout line, the two band-stop filters are integrated on the readout line, the readout cavity is coupled to the qubit, so that the readout module can obtain the state of the qubit based on the readout cavity and the readout line; the two band-stop filters are used to shield the operating frequency of the qubit. The length determination module is used to determine the length of the two band-stop filters based on coplanar waveguide theory and the center frequencies of the two band-stop filters. as well as, A distance determination module is used to determine the length of the target line segment of the readout line between the two band-stop filters as the distance between the two band-stop filters, based on coplanar waveguide theory and the operating frequency range of the qubit; the center frequency of the half-wavelength resonant cavity equivalent to the target line segment is outside the operating frequency range of the qubit; wherein the two band-stop filters are connected to the readout line, and the readout line between the two band-stop filters is coupled to the readout cavity so that the two band-stop filters are distributed on both sides of the readout cavity.

13. The apparatus according to claim 12, wherein, The frequency determination module is used for: Within a preset range based on the center frequency of the qubit, the center frequencies of the two band-stop filters are selected.

14. The apparatus according to claim 12 or 13, wherein, It also includes a simulation module for: The first determining unit is used to determine the initial design layout of integrating the two band-stop filters on the read line based on the length of the target line segment between the two band-stop filters and the length of the two band-stop filters. The simulation unit is used to simulate the initial design layout and obtain simulation results; The second determining unit is used to determine the initial design layout as the target design layout of an integrated bandstop filter when the simulation results meet the preset conditions. The preset conditions are that there are no spurious frequencies in the operating frequency range of the qubit and the center frequencies of the two bandstop filters are in the operating frequency range of the qubit.

15. The apparatus of claim 14, further comprising an adjustment module for: An adjustment unit is used to adjust the parameters of the two band-stop filters in the initial design layout based on the problem category in the simulation results when the simulation results do not meet the preset conditions. The verification unit is used to perform simulation verification based on the adjusted initial design layout until the final simulation result meets the preset conditions.

16. The apparatus according to claim 15, wherein, The adjustment unit is used for: If the problem category in the simulation results is that noise is generated within the operating frequency range of the qubit, the length of the target line segment between the two band-stop filters is adjusted to eliminate the noise.

17. The apparatus according to claim 16, wherein, The adjustment unit is used for: If the frequency of the noise frequency is higher than a first frequency threshold, the length of the target line segment is reduced. If the frequency of the noise is lower than the second frequency threshold, the length of the target line segment is increased; the second frequency threshold is less than the first frequency threshold.

18. The apparatus according to claim 15, wherein, The adjustment unit is used for: If the problem category in the simulation results is that the frequency difference between the simulation frequency of the two band-stop filters and the center frequency of the two band-stop filters is greater than a preset frequency difference, the length of the two band-stop filters shall be adjusted so that the frequency difference is less than the preset frequency difference.

19. The apparatus according to claim 18, wherein, The adjustment unit is used for: If the simulated frequency of the two band-stop filters is less than the center frequency of the two band-stop filters, the length of the two band-stop filters is reduced so that the frequency difference is less than the preset frequency difference; If the simulated frequency of the two band-stop filters is greater than the center frequency of the two band-stop filters, the length of the two band-stop filters is increased so that the frequency difference is less than the preset frequency difference.

20. The apparatus of claim 14, wherein an air bridge is provided at the connection between the two band-stop filters and the readout line in the initial design layout.

21. The apparatus according to any one of claims 14, further comprising a verification module for: Based on the obtained target design layout, at least one additional electromagnetic simulation verification is performed on the target design layout to obtain the verification results; If the verification results meet the preset conditions, the target design layout is determined as the final design layout of the integrated bandstop filter.

22. An electronic device, comprising: At least one processor; as well as A memory communicatively connected to the at least one processor; wherein, The memory stores instructions executable by the at least one processor, which, when executed by the at least one processor, enables the at least one processor to perform the method of any one of claims 1-10.

23. A non-transitory computer-readable storage medium storing computer instructions, wherein, The computer instructions are used to cause the computer to perform the method according to any one of claims 1-10.

24. A computer program product comprising a computer program that, when executed by a processor, implements the method according to any one of claims 1-10.

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