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

Abstract

The present disclosure provides a method and device for determining a filter in a superconducting quantum chip and related equipment, relates to the technical field of quantum chips, and particularly relates to the technical fields of superconducting quantum chips, superconducting quantum chip layout design, filter design and the like. The specific implementation scheme is: based on the working frequency range of a quantum bit in a superconducting quantum chip, determining the frequency parameters of two groups of filters of a reading module in the superconducting quantum chip; based on the frequency parameters of the two groups of filters and the working frequency range of the quantum bit, determining the layout structure parameters of the two groups of filters. In the present disclosure, a programmed design scheme is proposed, which can quickly and simply design an integrated band-stop filter meeting the filtering requirements, can improve the decoherence time of the adjustable quantum bit, and has a certain guiding significance for the design of the filter in the superconducting quantum chip.

Description

Technical Field

[0001] This disclosure relates to the field of quantum chip technology, and in particular to the fields of superconducting quantum chips, superconducting quantum chip layout design, and filter design. Background Technology

[0002] In superconducting quantum chips, a readout cavity is designed to couple with the qubit in order to measure its state. When the qubit jumps from a high energy level to a low energy level, the coupling between the qubit and the readout cavity allows a certain probability that the transitioning photon will enter the readout cavity, thus putting the readout cavity into an excited state. Furthermore, because the readout cavity is directly coupled to external losses (excitation), the excited state of the readout cavity also has a certain probability of transitioning back to the ground state, thereby leaking the qubit's energy. This process is called the Purcell effect, which affects the performance of superconducting quantum chips. Therefore, suppressing the Purcell effect is an urgent problem to be solved. Summary of the Invention

[0003] This disclosure provides a method, apparatus, and related equipment for determining filters in a superconducting quantum chip.

[0004] According to one aspect of this disclosure, a method for determining a filter in a superconducting quantum chip is provided, comprising:

[0005] Based on the operating frequency range of qubits in a superconducting quantum chip, the frequency parameters of two sets of filters in the readout module of the superconducting quantum chip are determined. The readout module includes a readout cavity and a readout line. The readout cavity is coupled to the qubit. The readout module acquires information from the qubit based on the readout cavity and the readout line. Each set of filters includes two band-stop filters, so that each set of filters is constructed as a frequency-misaligned filter. The two sets of filters are integrated on the readout line. The readout line between the two sets of filters is coupled to the readout cavity, so that the two sets of filters are distributed on both sides of the readout cavity.

[0006] Based on the frequency parameters of the two sets of filters and the operating frequency range of the qubits, the layout structure parameters of the two sets of filters are determined. The layout structure parameters include the spacing between the two sets of filters, the length of each band-stop filter in the same set of filters, and the spacing between different band-stop filters in the same set of filters.

[0007] According to another aspect of this disclosure, an apparatus for determining a filter in a superconducting quantum chip is provided, comprising:

[0008] The first determining module is used to determine the frequency parameters of two sets of filters in the readout module of the superconducting quantum chip based on the operating frequency range of the qubits in the superconducting quantum chip. The readout module includes a readout cavity and a readout line. The readout cavity is coupled to the qubits. The readout module acquires information about the qubits based on the readout cavity and the readout line. Each set of filters includes two band-stop filters so that each set of filters is constructed as a frequency-misaligned filter. The two sets of filters are integrated on the readout line. The readout line between the two sets of filters is coupled to the readout cavity so that the two sets of filters are distributed on both sides of the readout cavity.

[0009] The second determining module is used to determine the layout structure parameters of the two sets of filters based on the frequency parameters of the two sets of filters and the operating frequency range of the qubits. The layout structure parameters include the spacing between the two sets of filters, the length of each band-stop filter in the same set of filters, and the spacing between different band-stop filters in the same set of filters.

[0010] According to another aspect of this disclosure, a superconducting quantum chip is provided, comprising two sets of band-stop filters as described above.

[0011] According to another aspect of this disclosure, an electronic device is provided, comprising:

[0012] At least one processor; and

[0013] The memory is communicatively connected to the at least one processor; wherein,

[0014] 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.

[0015] 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.

[0016] 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.

[0017] In this embodiment, a procedural design scheme is proposed, which can easily and quickly design an integrated bandstop filter that meets the filtering requirements, improve the decoherence time of tunable qubits, and provide certain guidance for determining the filters in superconducting quantum chips.

[0018] 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

[0019] The accompanying drawings are provided to better understand this solution and do not constitute a limitation of this disclosure. Wherein:

[0020] Figure 1 This is a schematic diagram of the integrated structure of a bandpass filter and a readout line according to an embodiment of the present disclosure;

[0021] Figure 2 This is a schematic diagram of the structure of an independent filter according to another embodiment of the present disclosure;

[0022] Figure 3 This is a structural framework diagram of a band-stop filter according to another embodiment of the present disclosure;

[0023] Figure 4a It is a geometric configuration of a general integrated filter according to another embodiment of this disclosure;

[0024] Figure 4b This is a simulation diagram of a general integrated bandstop filter according to another embodiment of this disclosure;

[0025] Figure 5 This is a flowchart illustrating a filter design method in a superconducting quantum chip according to another embodiment of this disclosure;

[0026] Figure 6 It is the geometric configuration of the frequency error filter according to another embodiment of this disclosure;

[0027] Figure 7 This is a flowchart of a filter design method in a superconducting quantum chip according to another embodiment of the present disclosure;

[0028] Figure 8 This is a circuit schematic diagram of a band-stop filter according to another embodiment of this disclosure;

[0029] Figure 9 This is a simulation diagram of the schematic diagram of a band-stop filter circuit according to another embodiment of this disclosure;

[0030] Figure 10a This is a complete layout of the filter according to another embodiment of this disclosure;

[0031] Figure 10b This is a schematic diagram of bridging processing at the filter node according to another embodiment of this disclosure;

[0032] Figure 11 This is an electromagnetic simulation diagram of a filter according to another embodiment of this disclosure;

[0033] Figure 12 This is a schematic diagram of the structure of a filter design device in a superconducting quantum chip according to an embodiment of the present disclosure;

[0034] Figure 13 This is a block diagram of an electronic device used to implement the filter design method in the superconducting quantum chip of the present disclosure. Detailed Implementation

[0035] 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.

[0036] 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.

[0037] Quantum computing utilizes the principles of quantum mechanics to perform certain types of computations, such as in cryptography, chemical simulations, and optimization problems, 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 a superposition of multiple states simultaneously.

[0038] To verify the enormous potential and superiority of quantum computing, the hardware infrastructure for quantum computers must be constructed. Among these, the physical realization of quantum chips is the most crucial. After decades of development, the main physical realization methods for quantum chips currently include ion traps, photonics, 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 achieve practical quantum technology first."

[0039] A complete superconducting quantum chip needs to include various functional modules, such as readout modules, wiring modules, and qubit and coupling modules. Among these modules, the readout module is the first functional module involved in the actual measurement process, so its design is very important.

[0040] Measurement is an essential step in obtaining results from quantum computers. 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 the information contained within the readout module. 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.

[0041] For schemes that only add a readout cavity, the coupling state between the readout cavity 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.

[0042] Currently, one approach to suppressing the Purcell effect is to integrate filters within the chip. Known filter solutions include bandpass filters, stand-alone filters, and bandstop filters. Industry research has shown that integrating a bandpass filter reduces available space. Integrating the bandpass filter with the readout line can save space more effectively. However, developing and calibrating a high-quality bandpass filter requires significant costs. In this embodiment, Figure 1 A scheme integrating a bandpass filter and a readout line is shown. Figure 1 In the diagram, 101 represents a qubit, 102 represents a readout cavity, 103 represents a filter, and C... k C g This is the coupling capacitor. The upper right corner shows the equivalent circuit of the integrated bandpass filter and readout line scheme, where q is the quantum bit, r is the readout cavity, and F is the readout line.

[0043] Independent filters, on the other hand, would occupy even more space. In this embodiment of the disclosure... Figure 2 The scheme of independent filters is shown. In this scheme, 201 is a qubit, 202 is a readout cavity, 203 is a filter, and 204 is a readout line.

[0044] 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.

[0045] Figure 3 A possible structural framework for a band-stop filter is presented. However, although some theoretical research has been conducted, rapidly designing a suitable band-stop filter remains a challenge. This is especially true for tunable qubits, whose operating frequency varies within a certain range; when this range is large, it is necessary to extend the bandwidth of the band-stop filter.

[0046] 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.

[0047] 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 describe these aspects from three perspectives:

[0048] (1) The structure and function of a general reading module

[0049] Generally, a readout module contains 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, that is, when Δ >> g, their entangled state can be approximated in a relatively simple form, where g is the coupling strength between the readout cavity and the qubit.

[0050] The dispersion-limited readout commonly used in the industry is also achieved under dispersion-limited conditions. This is because the coupling between the readout cavity and the qubit under dispersion-limited conditions will cause a certain frequency shift in the readout cavity, which is approximately χ = g. 2 / Δ, and this offset is related to the state of the qubit. Therefore, the state of the qubit can be measured by detecting the resonant frequency of the readout cavity.

[0051] (2) Mechanism and inhibition of the Purcell effect

[0052] In quantum chips, the decoherence time of a qubit is one of the key indicators of its quality. 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.

[0053] 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 causes the Purcell effect.

[0054] In this embodiment, a semi-quantitative (theoretical) explanation of the Purcell effect is given simply. Under the dispersion limit, when the qubit and the readout cavity are in a steady state, the state function of this system is written as expression (1):

[0055]

[0056] Where |0> and |1> represent the ground state and the first excited state of the readout cavity, respectively, |±> represent the high and low energy levels of the qubit, 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.

[0057] 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 expression (2):

[0058]

[0059] 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. Expression (2) is the energy dissipation rate of the qubit caused by the Purcell effect.

[0060] Therefore, to improve the decoherence time of a qubit, it is necessary to suppress the Purcell effect, which requires introducing a filter into the quantum chip to reduce the κ value at the qubit's operating frequency. r It's very small.

[0061] (3) Coplanar Waveguide (CPW) Theory

[0062] In the design of quantum chips, coplanar waveguides are commonly used to fabricate resonant circuits. Generally, both 1 / 2-wavelength and 1 / 4-wavelength resonant cavities can achieve certain resonant modes. The fundamental frequency relationships of the 1 / 2-wavelength and 1 / 4-wavelength resonant cavities are shown in expressions (3) and (4), respectively:

[0063]

[0064]

[0065] Where c is the speed of light, l is the geometric length of the resonant cavity, ∈ eff ≈(∈ r +1) / 2 is the equivalent dielectric constant, ∈ r This is the relative permittivity of the substrate. It can be seen that to achieve the same resonant frequency, the length of a quarter-wavelength resonant cavity is half that of a half-wavelength resonant cavity; therefore, quarter-wavelength resonant cavities are more widely used.

[0066] Currently, typical integrated filters have the following geometric configurations and practical effects: Figure 4a and Figure 4b As shown. From Figure 4b As can be seen from this, when the requirement of 40dB isolation is met, Figure 4a The permissible frequency range is only about 400MHz, which is relatively small. Therefore, when the operating frequency of a qubit is higher, bandwidth expansion is necessary.

[0067] In one aspect, the bandwidth can be extended based on the frequency shift filter structure in this disclosure. Based on this, this disclosure proposes a filter design method for superconducting quantum chips. This method presents a programmed design and iterative process for designing integrated band-stop filters that meet filtering requirements. For example... Figure 5 The diagram shown is a flowchart illustrating a filter design method in a superconducting quantum chip according to an embodiment of this disclosure, including the following steps:

[0068] S501, based on the operating frequency range of the qubits in the superconducting quantum chip, determines the frequency parameters of two sets of filters in the readout module of the superconducting quantum chip. The readout module includes a readout cavity and a readout line. The readout cavity is coupled to the qubits, and the readout module acquires information from the qubits based on the readout cavity and readout line. Each set of filters includes two band-stop filters to construct each set of filters as frequency-misaligned filters. The two sets of filters are integrated on the readout line, and the readout line between the two sets of filters is coupled to the readout cavity, so that the two sets of filters are distributed on both sides of the readout cavity.

[0069] like Figure 6The diagram shows the frequency shift filter structure provided in this embodiment. For the quarter-wavelength resonant cavity at the open-circuit end (the end of the filter), based on coplanar waveguide theory, a specific filter length corresponds to the filter's center frequency. Simultaneously, since signal loss is extremely high at the filter's center frequency, it manifests as a deep dip in the transmission rate curve, such as... Figure 4b As shown. Therefore, one way to extend the bandwidth is to add another deep pit in the spectrum, and a possible layout structure of the frequency shift filter constructed in this way is as follows. Figure 6 As shown.

[0070] S502, based on the frequency parameters of the two sets of filters and the operating frequency range of the qubits, determines the layout structure parameters of the two sets of filters; the layout structure parameters include the spacing between the two sets of filters, the length of each band-stop filter in the same set of filters, and the spacing between different band-stop filters in the same set of filters.

[0071] In this embodiment of the disclosure, two sets of filters are integrated on the readout line, and the readout line between the two sets of filters is coupled to the readout cavity, so that the two sets of filters are distributed on both sides of the readout cavity. Figure 6 The frequency shift filter geometry shown consists of two sets of filters, each composed of four filters: M1, M2, M3, and M4. M1 and M2 form one set of filters, while M3 and M4 form the other. N1 is the readout line. Figure 6 As shown, the two sets of filters are integrated on the readout line.

[0072] The spacing between the two sets of filters is L2, and the spacing between different band-stop filters within the same set of filters is L1.

[0073] In this embodiment, the key parameters of the frequency error filter, such as the filter's center frequency, length, and spacing, can be designed based on the operating frequency range of the qubit. This standardizes the design method of the frequency error filter integrated on the readout line. This embodiment only requires the aforementioned parameters to design a frequency error filter that meets the design requirements, offering significant simplicity and improving the layout design efficiency of band-stop filters in quantum chips. Simultaneously, the frequency error filter provides a sufficiently large bandwidth to suppress qubit signal dissipation over a wide frequency range, improving the decoherence time of tunable qubits and effectively suppressing the Purcell effect. This embodiment provides greater scope for implementing more complex algorithm simulations, increasing filter bandwidth while also improving readout efficiency, offering guidance for filter design in superconducting quantum chips.

[0074] In this embodiment of the disclosure, each of the two sets of filters includes a first band-stop filter and a second band-stop filter, and the two sets of filters are distributed in a mirror-symmetrical manner on the readout line.

[0075] For example, such as Figure 6 The diagram shows the geometric configuration of the frequency shift filter. As explained earlier, M1 and M2 form one set of filters, and M3 and M4 form another set of filters. Specifically, M1 is the first band-stop filter in the first set, and M2 is the second band-stop filter in the first set. M3 is the second band-stop filter in the second set, and M4 is the first band-stop filter in the second set. Figure 6 As shown, M1 and M3 have almost the same length, and M2 and M4 have almost the same length. In the first group of filters, M1 and M2 are distributed in a mirror image symmetrically with the second group of filters, M3 and M4.

[0076] In this embodiment, the two sets of filters on the read line are distributed in a mirror-symmetric manner, which allows the filters to absorb the signals arriving at both ends of the read line, thereby minimizing signal leakage at the ports at both ends of the read line and improving the decoherence time of the qubit.

[0077] In this embodiment, each band-stop filter needs to shield the frequency of the qubits; therefore, the center frequency of the band-stop filter needs to be determined based on the operating frequency of the qubits. In implementation, based on the operating frequency range of the qubits in the superconducting quantum chip, the frequency parameters of the two sets of filters in the readout module of the superconducting quantum chip are determined, including: determining the center frequencies of the first and second band-stop filters based on the center frequencies within the operating frequency range of the qubits. Specifically, the center frequency of the first band-stop filter in the first set of filters is the same as the center frequency of the first band-stop filter in the second set of filters, and the center frequency of the second band-stop filter in the first set of filters is the same as the center frequency of the second band-stop filter in the second set of filters.

[0078] That is, Figure 6 As shown, M1 and M4 have the same center frequency, and M2 and M3 have the same center frequency.

[0079] In this embodiment of the disclosure, in order to enable the band-stop filter in the frequency error filter to shield the frequency of the qubit, and to enable the two band-stop filters in the same group of filters to form a suitable frequency error filter, in this embodiment of the disclosure, the frequency difference between the center frequency of the first band-stop filter and the center frequency of the second band-stop filter and the center frequency of the qubit is less than a first threshold; the frequency difference between the center frequency of the first band-stop filter and the center frequency of the second band-stop filter is less than a second threshold and greater than a third threshold.

[0080] In this design, the center frequency of the qubit is pre-set and is a known parameter. Therefore, in order to shield the frequency of the qubit, the center frequency of the band-stop filter and the center frequency of the qubit cannot differ too much. In this embodiment, the frequency difference between the two must be less than a first threshold, which can be set according to requirements, but in principle, the first threshold should be less than 1 GHz. Furthermore, to construct the frequency misalignment filter, the difference between the center frequencies of the first band-stop filter and the second band-stop filter must be greater than a third threshold, meaning the center frequencies of the first band-stop filter and the second band-stop filter are not completely identical. Additionally, to enable the two band-stop filters in the frequency misalignment filter to work together and widen the bandwidth, the difference between the center frequencies of the first band-stop filter and the second band-stop filter cannot be too large and must be less than a second threshold, which must be less than 1 GHz.

[0081] Since a band-stop filter performs well when its design frequency is roughly at the center of its operating frequency spectrum, the center frequency of the band-stop filter in this embodiment is close to the center frequency of the qubit. This allows the filter to better suppress qubit signal dissipation and improve the performance of the quantum chip. Furthermore, maintaining the frequency difference between two band-stop filters within the same filter group within a reasonable range effectively widens the filter's bandwidth and better adapts to the qubit's operating frequency range.

[0082] In addition to using a frequency-shifting filter structure to extend the bandwidth in this embodiment, the operating bandwidth of the filter can also be increased by reducing its impedance. In practice, the filter impedance can be reduced based on the following principle, thereby increasing the filter's bandwidth.

[0083] Based on transmission line theory, this embodiment of the disclosure defines the input impedance Z of the lossless transmission line. in Represented as expression (5),

[0084]

[0085] Where Z0 is the characteristic impedance of the transmission line, Z L Let be the load impedance, β = ω / c be the propagation constant, ω be the input frequency of the transmission line, and l be the transmission line length. For an open-circuit 1 / 4 wavelength lossless transmission line, Z... L =∞, l = λ / 4 = πc / 2ω0, where ω0 is the resonant frequency of the specific transmission line. Therefore, the input impedance can be expressed as in expression (6):

[0086]

[0087] Near the resonance point, the above equation can be simplified to expression (7):

[0088]

[0089] in, The input impedance of an open-circuit transmission line is given by β = ω / c, where ω = ω0 + δ, and δ << ω0. Here, δ is a very small frequency offset, primarily used to obtain the input impedance near the transmission line's resonant frequency.

[0090] It can be seen from this that the input impedance of this transmission line is actually the same as the input impedance of a series RLC circuit. The input impedance of a series RLC circuit near the resonant point can be written as expression (8).

[0091] Z in ≈j2Lδ(8)

[0092] Where L is the equivalent inductance. Therefore, a quarter-wavelength lossless transmission line with an open end can be equivalent to a series RLC circuit. Considering that a filter is such a quarter-wavelength lossless transmission line with an open end, and is directly connected to external losses, the quality factor of the filter can be derived as shown in expression (9):

[0093]

[0094] Among them, Z F Let be the characteristic impedance of the filter. Equation (9) shows that the magnitude of the filter's characteristic impedance affects the filter's quality factor. Since the quality factor is inversely proportional to the bandwidth, as shown in expression (10), reducing the filter's impedance is also a way to increase the bandwidth.

[0095]

[0096] Where ω0 is the resonant frequency of a specific transmission line, BW is the bandwidth of the frequencies on both sides of the resonant point, and Q... F This is the quality factor.

[0097] In summary, in the embodiments disclosed herein, bandwidth can be extended by using a frequency shift filter structure, or by reducing impedance.

[0098] Based on the theoretical foundation described above, the method for determining the filter in the superconducting quantum chip in this embodiment may include three stages, which will be described in detail below:

[0099] Phase 1: Constructing the circuit schematic

[0100] The construction of the circuit schematic can include the following parts:

[0101] 1) Determine the center frequency of the first band-stop filter and the center frequency of the second band-stop filter in the same group of filters.

[0102] As explained earlier, the center frequencies of the first and second band-stop filters are close to the center frequencies of the qubits, but there is a certain difference between their center frequencies. Therefore, a frequency-misalignment filter capable of shielding the qubit frequencies and extending the bandwidth can be constructed.

[0103] 2) Determine the length of each band-stop filter within the same filter group.

[0104] In this embodiment of the disclosure, determining the length of each band-stop filter within the same group of filters can be performed by the following steps:

[0105] Step A1: Obtain the center frequency of the first band-stop filter and the center frequency of the second band-stop filter from the frequency parameters.

[0106] Step A2: Based on the inverse relationship between filter length and filter center frequency expressed by coplanar waveguide theory, determine the length of the first band-stop filter and the length of the second band-stop filter.

[0107] In step A1, the center frequencies of each band-stop filter in the same group of filters are determined based on the center frequencies of the qubits. Therefore, according to the coplanar waveguide theory described above, the length of the filter can be calculated using expression (3) or expression (4). Since the quarter-wavelength resonant cavity is relatively short, expression (4) is preferred to determine the lengths of the two band-stop filters. The relative permittivity of the substrate is known.

[0108] In this embodiment, the length of the band-stop filter is determined based on coplanar waveguide theory, which allows for accurate and simple design of each band-stop filter length, standardizing the band-stop filter design process. Furthermore, this simple method enables the design of band-stop filters that meet corresponding performance requirements, thereby improving the decoherence time of qubits.

[0109] 3) Determine the spacing L1 between different band-stop filters within the same filter group and the spacing L2 between two filter groups.

[0110] In this embodiment of the disclosure, for the sake of system symmetry, two sets of filters are placed symmetrically at both ends of the readout line, each set of filters having two filters of different lengths. Therefore, it is necessary to determine the spacing between different band-stop filters within the same set of filters and the spacing between the two sets of filters.

[0111] There may be three types of noise in this structure: First, the two sets of filters and a section of readout line between the two sets of filters can be equivalent to a half-wavelength resonant cavity; second, only a section of readout line between the two sets of filters can be equivalent to a half-wavelength resonant cavity; third, a section of readout line between different band-stop filters in the same set of filters can be equivalent to a half-wavelength resonant cavity.

[0112] Based on experience from multiple design iterations, the first type of noise can be ignored due to the large spacing between the two filter sets. For this reason, only the latter two types of noise need to be considered. Through calculation, the spacing L1 between different band-stop filters within the same filter set and the spacing L2 between the two filter sets can be roughly determined.

[0113] In this embodiment of the disclosure, the method for determining the spacing L1 between different band-stop filters within the same set of filters and the spacing L2 between two sets of filters will be described in detail:

[0114] (1) Determine the spacing L1 between different bandstop filters within the same group of filters.

[0115] In this embodiment of the disclosure, determining the spacing between different band-stop filters within the same group of filters can be performed by the following steps:

[0116] Step B1: The first band-stop filter, the second band-stop filter, and a section of readout line between the first band-stop filter and the second band-stop filter are equivalent to a first half-wavelength resonant cavity. Based on the operating frequency range of the qubit, the center frequency of the first half-wavelength resonant cavity is determined, wherein the center frequency of the first half-wavelength resonant cavity is outside the operating frequency range of the qubit.

[0117] That is, the frequency generated by the first half-resonant cavity is a noise frequency. In order to shift this noise frequency out of the operating frequency range of the qubit, the frequency of the noise frequency can be determined according to the operating frequency range of the qubit in this embodiment. In this embodiment, it is sufficient to select a frequency outside the operating frequency range of the qubit as the center frequency of the noise frequency. In order to distinguish it as much as possible, the frequency of the noise frequency should differ from the upper or lower limit of the operating frequency of the qubit by a specified value.

[0118] Step B2: Based on the center frequency of the first half-wavelength resonant cavity and the coplanar waveguide theory, determine the readout line length between the first band-stop filter and the second band-stop filter in the same group of filters as the spacing between different band-stop filters.

[0119] That is, after determining the center frequency of the first half-wavelength resonant cavity, the spacing L1 can be solved according to the aforementioned coplanar waveguide theory.

[0120] Alternatively, it can be understood that, for the sake of system symmetry, the embodiments of this disclosure symmetrically arrange two sets of filters at both ends of the readout line. Each set of filters has two band-stop filters with different frequencies. Therefore, by adjusting the spacing between the two band-stop filters (i.e., ... Figure 6 By adjusting the length of L1 in the qubit, the noise frequency can be shifted out of the operating frequency range of the qubit.

[0121] In this embodiment, the spacing between two band-stop filters in the same group of filters that meet the design requirements is determined based on the center frequency of the first half-wavelength resonant cavity and the coplanar waveguide theory. This allows for accurate determination of the spacing between the two band-stop filters in the same group of filters, ensuring that the designed frequency-misaligned filter meets the design requirements. This helps improve the filter's performance in filtering out noise, thereby effectively mitigating the Purcell effect and reducing the decoherence time of the quantum bit.

[0122] In this embodiment of the disclosure, based on the center frequency of the first half-wavelength resonant cavity and the coplanar waveguide theory, the spacing L1 between the first band-stop filter and the second band-stop filter within the same group of filters is determined, which can be specifically performed by the following steps:

[0123] Step C1: Based on the center frequency of the first half-wavelength resonant cavity and the coplanar waveguide theory, determine the total length of the first half-wavelength resonant cavity.

[0124] Step C2: The difference between the total length of the first half-wavelength resonant cavity and the target sum is determined as the distance between the first and second band-stop filters within the same filter group, i.e., the readout line length between the first and second band-stop filters. The target sum is the sum of the lengths of the first and second band-stop filters.

[0125] In this embodiment of the disclosure, in order to shift the noise caused by the first band-stop filter and the second band-stop filter in the same set of filters to outside the operating frequency range of the quantum bit, this can be achieved by adjusting the length of the read line between the first band-stop filter and the second band-stop filter. That is, by adjusting... Figure 6 The length of the L1 readout line is used to determine this. Since this transmission line segment is equivalent to a first half-wavelength resonant cavity, the total length of the first half-wavelength resonant cavity can be obtained according to coplanar waveguide theory. This total length includes the lengths of the first band-stop filter, the second band-stop filter, and the length L1 of the transmission line between them. Therefore, the difference between the total length of the first half-wavelength resonant cavity and the sum of the lengths of the first and second band-stop filters is the spacing between them.

[0126] In this embodiment, coplanar waveguide theory can be used to more accurately calculate the total length of the first half-wavelength resonant cavity. The difference between the total length of the first half-wavelength resonant cavity and the sum of the lengths of the first and second band-stop filters is determined as the spacing between the first and second band-stop filters. This standardizes the design process for the spacing between the first and second band-stop filters in the frequency shift filter, saves computer resources, and improves the design efficiency of the band-stop filter integrated on the readout line. Simultaneously, the designed frequency shift filter better meets performance requirements and improves the decoherence time of the qubit.

[0127] (2) Determine the spacing between the two sets of filters

[0128] In some embodiments, as described above, the readout line L2 between the two sets of filters also generates noise, which needs to be shifted out of the operating frequency range of the qubit. To this end, the spacing between the two sets of filters is determined, which can be specifically performed as follows:

[0129] Step D1: Equivalently represent a section of readout line between the two sets of filters as a second half-wavelength resonant cavity. Determine the center frequency of the second half-wavelength resonant cavity based on the operating frequency range of the qubits, wherein the center frequency of the second half-wavelength resonant cavity is outside the operating frequency range of the qubits.

[0130] Step D2: Based on the center frequency of the second half-wavelength resonant cavity and the coplanar waveguide theory, determine the reading line length between the two sets of filters as the spacing between the two sets of filters.

[0131] In this embodiment of the disclosure, such as Figure 6 As shown, in order to shift the noise caused by a section of readout line between the two sets of filters outside the operating frequency range of the quantum bit, the spacing between the two sets of filters can be adjusted, i.e. Figure 6 L2 in the middle.

[0132] For example, assuming the highest frequency in the operating range of the qubit is 8 GHz, and the center frequency of the second half-wavelength resonant cavity, determined based on the center frequency of the qubit, is 9 GHz, the spacing between the two sets of filters, L2, can be calculated based on expression (4) of the coplanar waveguide theory when the center frequency of the second half-wavelength resonant cavity is 9 GHz. If, in order to reduce the design layout size, it is also necessary to ensure that the spacing between the two sets of filters is not too small, the spacing between the two sets of filters can be adjusted appropriately.

[0133] In this embodiment, based on the center frequency of the second half-wavelength resonant cavity and coplanar waveguide theory, the spacing between the two sets of filters can be calculated accurately and conveniently. This method standardizes the design process for the spacing between the two sets of filters in a frequency-shifting filter, while saving computer resources and improving the design efficiency of the band-stop filter integrated on the readout line. Furthermore, the designed frequency-shifting filter better meets performance requirements and improves the decoherence time of the qubit.

[0134] In other possible embodiments, besides determining the spacing between the two sets of filters using coplanar waveguides as described above, the spacing between the two sets of filters can also be determined as follows:

[0135] Step E1: Based on the lowest frequency within the operating frequency range of the qubit, determine the first length required for the third half-wavelength resonant cavity that meets the lowest frequency.

[0136] For example, in superconducting quantum chips, the frequency range of qubits is typically 3-8 GHz. Due to noise caused by other resonant modes, this frequency range must be shifted out. This can be achieved by adjusting the spacing between two sets of filters. When the lowest frequency of the qubit is 3 GHz, a critical value a1 is calculated using coplanar waveguide theory; this a1 represents the first length required for the third half-wavelength resonant cavity at the lowest frequency.

[0137] Step E2: Based on the highest frequency within the operating frequency range of the qubit, determine the second length required for a third half-wavelength resonant cavity that matches the highest frequency; this second length is less than the first length.

[0138] For example, when the highest frequency of a quantum bit is 8 GHz, another critical value a2 is calculated using coplanar waveguide theory. This is the second length required for the third half-wavelength resonant cavity at the highest frequency. In general, the second length is less than the first length, i.e., a1 > a2.

[0139] Step E3: When the size of the superconducting quantum chip is smaller than the first length, a section of the readout line between the two sets of filters is equivalent to a second half-wavelength resonant cavity, and the length of the second half-wavelength resonant cavity is determined to be smaller than the second length, so as to obtain the spacing between the two sets of filters.

[0140] It is understandable that if L2 is within the range of [a2, a1], the generated noise will be within the operating frequency range of the qubit. Therefore, L2 needs to be greater than a1 or less than a2 to remove the noise from the operating frequency range of the qubit.

[0141] Since the size of current superconducting quantum chips is approximately on the order of 10 mm, when the first length a1 is larger than the size of the quantum chip, the second length a2 can be determined as the critical value for the spacing between the two sets of filters. Therefore, the length of L2 can be determined from the range of lengths smaller than a2.

[0142] In this embodiment of the disclosure, the threshold of the spacing between two sets of filters is determined by the operating range of the qubit, which can standardize the design process of the band-stop filter. This simple method improves the design efficiency of the band-stop filter, enables the design of frequency-misaligned filters that meet the corresponding performance requirements, alleviates the Purcell effect, and improves the decoherence time of the qubit.

[0143] 4) Set the initial impedance of the filter and build the circuit schematic.

[0144] To improve the design iteration efficiency of the filter, this disclosure first uses circuit schematics for simulation verification. Electromagnetic simulation can then be used for further verification, allowing for iterative development of an integrated band-stop filter that better meets performance requirements.

[0145] In this embodiment of the disclosure, to match the impedance of the industry standard, the impedance of the read line is generally designed to be around 50 ohms. Since the integrated band-stop filter is integrated with the read cavity, the filter impedance is initially set to 50 ohms to reduce process requirements.

[0146] Based on the above parameters, a certain circuit schematic can be constructed. The specific steps for constructing the circuit schematic are as follows:

[0147] Step F1: Construct the circuit schematic based on the layout structure parameters of the two sets of filters.

[0148] The layout structure parameters of the two filter sets include the spacing L2 between the two filter sets and the length of each band-stop filter within the same filter set (i.e., Figure 6 The lengths of M1, M2, M3, and M4 in the filter group, the spacing L1 between different band-stop filters within the same filter group, and the initial impedance of each band-stop filter.

[0149] Step F2: Perform circuit simulation based on the circuit schematic to obtain the circuit simulation results.

[0150] In this embodiment of the disclosure, since the layout structure parameters of the two sets of filters have been initially determined, and in order to improve design efficiency, the design circuit schematic is built in the relevant software and the initial simulation is performed.

[0151] Step F3: If there is noise in the circuit simulation results, adjust the layout structure parameters of the two sets of filters based on the frequency of the noise. The noise is the signal generated by the components inside the read module that belongs to the operating frequency range of the quantum bit and the read cavity.

[0152] In this embodiment of the disclosure, if the simulation results of the circuit schematic show noise, adjustments can be made adaptively based on the following two specific situations:

[0153] Scenario 1: When the frequency of noise is lower than the first frequency threshold, increase the spacing between different band-stop filters within the same filter group to reduce the frequency of noise.

[0154] That is, when the noise frequency is low and the frequency is relatively low, the influence of the noise frequency can be further reduced by increasing the spacing L1 between the first band-stop filter and the second band-stop filter.

[0155] In this embodiment of the disclosure, when the spurious frequency is low, the spacing between different band-stop filters within the same set of filters is increased to make the spurious frequency even lower. This keeps the spurious frequency outside the operating frequency range of the quantum bit, effectively ensuring the performance of the two sets of band-stop filters, mitigating the Purcell effect, and improving the decoherence time of the quantum bit.

[0156] Scenario 2: When the frequency of the noise is higher than the second frequency threshold, reduce the spacing between the two sets of filters to increase the frequency of the noise.

[0157] That is, when the noise frequency is high-frequency, the noise frequency can be shifted out of the operating frequency range of the quantum bit by reducing the spacing L2 between the two sets of filters.

[0158] In this embodiment of the disclosure, when the spurious frequency is high, the spacing between the two sets of filters is reduced so that the spurious frequency is even higher. This can keep the spurious frequency outside the operating frequency range of the quantum bit, effectively ensuring the performance of the two sets of band-stop filters, mitigating the Purcell effect, and improving the decoherence time of the quantum bit.

[0159] In this embodiment of the disclosure, the simulation speed of the circuit schematic is much greater than that of the electromagnetic simulation. Therefore, using the circuit schematic to assist in the design first can greatly improve the design efficiency of the quantum chip.

[0160] Phase 2: Adjust and iterate relevant parameters

[0161] In this embodiment, bandwidth can be increased by using a frequency shift filter structure, but the frequency shift filter needs to meet certain performance requirements. Therefore, the bandwidth increase achieved by simply using a frequency shift filter is limited. To address this, based on the foregoing, bandwidth can be further increased by adjusting the filter impedance. Specifically, if there are no noise frequencies in the circuit simulation results and the bandwidth of the target isolation does not meet the desired bandwidth, the impedance values ​​of each filter in both sets of filters can be reduced to increase the bandwidth of the target isolation.

[0162] For example, after repeatedly adjusting the spacing L2 between the two sets of filters and the spacing L1 between the first and second band-stop filters in the same set of filters and performing multiple simulations, if there are no noise frequencies in the simulation results, but the bandwidth in the circuit schematic simulation results is small and does not meet the expected bandwidth, then reducing the impedance can be considered to further improve the bandwidth of the filter.

[0163] In implementation, the characteristic impedance can be reduced by increasing the linewidth ratio of the filter structure. Specifically, using... Figure 6 Taking filter M1 as an example, the linewidth ratio of the filter structure is... Figure 6 The width of the center conductor of M1 ( Figure 6 The medium-dark gray area) and the etched area outside M1 ( Figure 6 The line width ratio of the midpoint-shaped fill portion.

[0164] In practice, the linewidth of each filter in both sets of filters can be adjusted to the same value simultaneously. However, the width of the readout line is not adjusted.

[0165] In this embodiment, the bandwidth of the band-stop filter can be further improved by reducing the impedance value of the filter to increase its bandwidth, thereby adapting to the operating frequency range of the qubit. This method standardizes the design process of the band-stop filter, and the designed band-stop filter can adapt to different tunable frequency qubits, effectively mitigating the Purcell effect and improving the decoherence time of the qubit.

[0166] Phase 3: Electromagnetic Simulation Verification

[0167] After the adjustments in the second stage described above, resulting in a circuit schematic that meets the design requirements, the corresponding circuit layout is drawn to facilitate electromagnetic simulation verification, further ensuring that the designed band-stop filter meets the corresponding performance requirements. Specifically, this can be executed as follows:

[0168] Step G1: If the circuit principle simulation results meet the expected results, draw the circuit layout based on the circuit schematic; in this case, both sets of filters are drawn as curved shapes in the circuit layout.

[0169] In this embodiment of the disclosure, in order to reduce the footprint of the filter, it is considered to bend the filter during the circuit layout process.

[0170] The desired results may include: the first band-stop filter in the frequency error filter is near the corresponding center frequency range; the second band-stop filter is within the corresponding center frequency range; the noise generated by the first band-stop filter, the second band-stop filter, and the readout lines between them is shifted out of the operating frequency range of the qubit; the noise generated by the readout lines between the two sets of filters is also shifted out of the operating frequency range of the qubit; and the bandwidth meets the desired bandwidth requirements.

[0171] Step G2: Perform electromagnetic simulation verification based on the circuit layout.

[0172] In this embodiment of the disclosure, the circuit layout drawn in step G1 is imported into electromagnetic simulation software for simulation verification.

[0173] Step G3: Based on the electromagnetic simulation verification results, if the expected results are met, determine the two sets of filters in the circuit layout as the final filter design results.

[0174] In this embodiment, drawing the circuit layout using a circuit schematic makes layout and routing optimization easier, allowing for rapid iterative debugging to achieve the desired results. Furthermore, based on this schematic, an electromagnetic simulation is performed to verify the designed circuit layout, ensuring that the final designed frequency error filter meets the required performance, effectively mitigating the Purcell effect and improving the decoherence time of the qubits.

[0175] In this embodiment of the disclosure, if the electromagnetic simulation verification results determine that the expected results are not met, the electromagnetic simulation verification is repeated by adjusting the circuit layout until the expected results are met.

[0176] For example, when the electromagnetic simulation results need to be adjusted, the designed circuit layout can be analyzed, the circuit layout can be adjusted in combination with the specific problem, and simulation verification can be carried out until the desired result is obtained.

[0177] In this embodiment of the disclosure, by performing electromagnetic simulation on the circuit layout, and continuing to iteratively adjust the circuit layout if the simulation results do not meet the expected results, a band-stop filter that meets the corresponding performance requirements can be iteratively designed, effectively mitigating the Purcell effect.

[0178] To make it easier to understand, the method described above can be used... Figure 7 The flowchart shown is used for illustration.

[0179] Step 1: Determine the center frequencies of the first and second band-stop filters in the same group of filters;

[0180] Step 2: Determine the geometric lengths of the first and second band-stop filters in the same group of filters;

[0181] Step 3: Determine the spacing between the first band-stop filter and the second band-stop filter in the same group of filters, as well as the spacing between the two groups of filters;

[0182] Step 4: Set the initial impedance of the filter and build the circuit schematic;

[0183] Step 5: Adjust the spacing between the first and second band-stop filters in the same group of filters, as well as the spacing between the two groups of filters;

[0184] Step 6: Reduce filter impedance to extend bandwidth;

[0185] Step 7: Draw the circuit layout based on the circuit schematic that meets the design requirements;

[0186] Step 8: Conduct electromagnetic simulation verification.

[0187] To facilitate understanding, a specific example is provided in this disclosure for demonstration and verification, aiming to demonstrate the rationality and simplicity of the method provided in this disclosure.

[0188] I. Constructing the circuit schematic

[0189] Step 1: Determine the center frequencies of the first and second band-stop filters in the same group of filters.

[0190] In this example, the center frequency of the qubit is determined to be 4.5 GHz, with a minimum frequency of 4.2 GHz and a maximum frequency of 4.8 GHz; the readout cavity frequency is approximately 7 GHz; and the filter is required to have a bandwidth of at least 600 MHz with an isolation of 40 dB. To avoid a large difference in length between the two nearest-neighbor filters, the center frequencies of these two filters are chosen to be 4.4 GHz and 4.6 GHz, respectively.

[0191] Step 2: Determine the geometric lengths of the first and second band-stop filters in the same set of filters.

[0192] Using the coplanar waveguide theory described above, the geometric lengths of the first and second band-stop filters in the same set of filters can be estimated. Meanwhile, in this example, a relative permittivity of 10.85 is chosen, thus yielding expressions (11) and (12).

[0193]

[0194]

[0195] Step 3: Determine the spacing between the first and second band-stop filters in the same group of filters, as well as the spacing between the two groups of filters.

[0196] To shift the noise caused by a section of readout line between the first and second band-stop filters in the same filter group to outside 4 GHz, i.e., outside the operating frequency range of the qubits, the length L1 of this section of readout line between the first and second band-stop filters can be adjusted. Since such a transmission line is equivalent to a half-wavelength resonant cavity, it can be known that when the resonant frequency is 4 GHz, its total length is given by expression (13):

[0197]

[0198] From this, we can calculate... To reduce the size of the design layout, L1 = 1705um is chosen.

[0199] To shift the resonant mode caused by the readout line between the two filter sets beyond 8 GHz, the spacing L2 between the two filter sets needs to be adjusted. When the resonant mode is at 8 GHz, a critical value can be calculated. To reduce the size of the design layout, while ensuring that the length is not too small, L2 = 6000um can be selected.

[0200] Step 4: Set the initial impedance of the filter to approximately 50 ohms and build the circuit schematic.

[0201] To match industry standard impedance, the impedance of the read lines is typically designed to be around 50 ohms. Since the integrated band-stop filter is integrated with the read cavity, the filter impedance is initially set to 50 ohms to reduce manufacturing requirements.

[0202] Based on the above parameters, a certain circuit schematic is constructed, such as... Figure 8 The diagram shown is a schematic of the circuit principle of a band-stop filter.

[0203] II. Adjust and iterate relevant parameters

[0204] Step 5: Adjust the spacing between the two nearest neighbor filters and the two sets of filters and perform simulation.

[0205] The circuit schematic was simulated, and the results are as follows: Figure 9 The simulation results of the band-stop filter circuit schematic are shown.

[0206] No noise was observed in the simulation results of the circuit schematic. Furthermore, the center frequencies of the two filters were close to the original design values. This indicates that the above design parameters are likely reasonable, and no adjustments to the lengths of the various structures are needed at the circuit schematic level.

[0207] Step 6: Reduce the filter impedance to expand the bandwidth.

[0208] Because this disclosure requires a bandwidth of at least 600MHz at an isolation level of 40dB, it is necessary to check whether the simulation results meet the requirements. Figure 9 As shown, the simulation results at the circuit principle level are very ideal. With an isolation of 40dB, there is a bandwidth of about 1GHz, so the impedance can remain unchanged.

[0209] III. Electromagnetic Simulation Verification

[0210] Step 7: Draw the design layout based on the circuit schematic that meets the design requirements.

[0211] To reduce the filter's footprint, a bending mechanism is considered, as shown in Figure 10. Figure 10a This is the complete layout of the filter, where the filter has been bent. Figure 10b The black area represents the bridging treatment at the nodes to suppress the complex electromagnetic environment at the nodes.

[0212] Step 8: Perform electromagnetic simulation verification

[0213] The design layout drawn in step seven was simulated and verified. The simulation results are as follows: Figure 11 The image shows the electromagnetic simulation results of the designed filter. Figure 11 It can be seen that the electromagnetic simulation results are similar to the simulation results of the circuit schematic.

[0214] contrast Figure 9 and Figure 11 It can be found Figure 9 and Figure 11 Both simulations provide a bandwidth of only 1 GHz, but due to some simulation error, the filter's center frequency deviates by approximately 100 MHz. Although there is a deviation, it does not affect the operating frequency of the shielded qubits of the frequency-misaligned filter. Moreover, it can be seen that the circuit principle simulation results are almost consistent with the electromagnetic simulation verification results, therefore the filter meets the design requirements.

[0215] It is understood that the band-stop filter designed in this embodiment does not need to strictly meet the corresponding frequency requirements. Even with some deviations, a band-stop filter that meets the corresponding performance requirements can still be obtained, which can reduce the design, debugging, and iteration development costs compared to a band-pass filter. Moreover, the band-stop filter is integrated on the readout line, becoming an integrated band-stop filter, which can also save the space occupied by the filter.

[0216] In summary, this disclosure provides a method for determining the filter in a superconducting quantum chip. During the design process, only given design parameters are required; the design, simulation verification, and iteration of the band-stop filter in the superconducting quantum chip can be performed according to the procedures outlined in this disclosure, ultimately completing the design of the band-stop filter. The integrated band-stop filter designed in this disclosure can improve the decoherence time of tunable qubits and also increase readout efficiency, providing guidance for the design of filters in superconducting quantum chips.

[0217] The main design effects are summarized as follows:

[0218] 1. Simple design: The embodiments of this disclosure only require a few initial parameters, and then an integrated bandstop filter that meets the design requirements can be quickly iterated according to the process of the embodiments of this disclosure. It has a sufficiently large bandwidth to suppress the dissipation of qubits over a large frequency range.

[0219] 2. Reliable Results: The embodiments of the invention disclosed herein take into account possible deviations, and will continue to iterate if the judgment conditions are not met; at the same time, this design process needs to be verified by simulation of circuit principles and electromagnetic fields. Therefore, the results are reliable.

[0220] 3. High practicality: The integrated band-stop filter in this embodiment only requires minor modifications to the readout line. The addition of the filter structure and its bending saves space and does not have too much negative impact on the subsequent large-scale design. For direct readout cavity chip layouts without filters, the filter design can be completed with minimal modifications.

[0221] 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.

[0222] Based on the same technical concept, this disclosure provides a superconducting quantum chip, which includes two sets of band-stop filters.

[0223] In this embodiment, the frequency error filter constructed by two sets of band-stop filters can provide a sufficiently large bandwidth to suppress the dissipation of the quantum bit signal, effectively suppressing the Purcell effect and improving the performance of the superconducting quantum chip.

[0224] Based on the same technical concept, this disclosure provides an apparatus 1200 for determining the filter in a superconducting quantum chip, such as... Figure 12 As shown, the device includes:

[0225] The first determining module 1201 is used to determine the frequency parameters of two sets of filters in the readout module of the superconducting quantum chip based on the operating frequency range of the qubits in the superconducting quantum chip. The readout module includes a readout cavity and a readout line. The readout cavity is coupled to the qubits. The readout module acquires information about the qubits based on the readout cavity and the readout line. Each set of filters includes two band-stop filters so that each set of filters is constructed as a frequency-misaligned filter. The two sets of filters are integrated on the readout line. The readout line between the two sets of filters is coupled to the readout cavity so that the two sets of filters are distributed on both sides of the readout cavity.

[0226] The second determining module 1202 is used to determine the layout structure parameters of the two sets of filters based on the frequency parameters of the two sets of filters and the operating frequency range of the qubits. The layout structure parameters include the spacing between the two sets of filters, the length of each band-stop filter in the same set of filters, and the spacing between different band-stop filters in the same set of filters.

[0227] In some embodiments, the first determining module includes:

[0228] The first determining submodule is used to determine the center frequencies of the first band-stop filter and the second band-stop filter based on the center frequency within the operating frequency range of the quantum bit.

[0229] The frequency difference between the center frequency of the first band-stop filter and the center frequency of the second band-stop filter and the center frequency of the quantum bit is less than the first threshold; the frequency difference between the center frequency of the first band-stop filter and the center frequency of the second band-stop filter is less than the second threshold and greater than the third threshold.

[0230] In some embodiments, the second determining module includes:

[0231] The acquisition submodule is used to obtain the center frequency of the first band-stop filter and the center frequency of the second band-stop filter from the frequency parameters;

[0232] The second determining submodule is used to determine the length of the first band-stop filter and the length of the second band-stop filter based on the inverse relationship between the filter length and the filter center frequency expressed by coplanar waveguide theory.

[0233] In some embodiments, the second determining module further includes:

[0234] The first equivalent determination submodule is used to equate the first band-stop filter, the second band-stop filter, and a section of readout line between the first band-stop filter and the second band-stop filter to a first half-wavelength resonant cavity, and to determine the center frequency of the first half-wavelength resonant cavity based on the operating frequency range of the quantum bits, wherein the center frequency of the first half-wavelength resonant cavity is outside the operating frequency range of the quantum bits.

[0235] The third determining submodule is used to determine the readout line length between the first band-stop filter and the second band-stop filter in the same group of filters as the spacing between different band-stop filters, based on the center frequency of the first half-wavelength resonant cavity and the coplanar waveguide theory.

[0236] In some embodiments, the third determining submodule is specifically used for:

[0237] Based on the center frequency of the first half-wavelength resonant cavity and the coplanar waveguide theory, the total length of the first half-wavelength resonant cavity is determined.

[0238] The difference between the total length of the first half-wavelength resonant cavity and the target sum is determined as the readout line length between the first band-stop filter and the second band-stop filter within the same filter group. The target sum is the sum of the lengths of the first band-stop filter and the second band-stop filter.

[0239] In some embodiments, the second determining module further includes:

[0240] The second equivalent determination submodule is used to equate a section of readout line between the two sets of filters to a second half-wavelength resonant cavity. Based on the operating frequency range of the qubit, the center frequency of the second half-wavelength resonant cavity is determined, wherein the center frequency of the second half-wavelength resonant cavity is outside the operating frequency range of the qubit.

[0241] The fourth determination submodule is used to determine the length of the readout line between the two sets of filters as the spacing between the two sets of filters, based on the center frequency of the second half-wavelength resonant cavity and the coplanar waveguide theory.

[0242] In some embodiments, the second determining module further includes:

[0243] A first length determination submodule is used to determine, based on the lowest frequency within the operating frequency range of the qubit, the first length required for a third half-wavelength resonant cavity that conforms to the lowest frequency; and...

[0244] The second length determination submodule is used to determine the second length required for a third half-wavelength resonant cavity that meets the highest frequency within the operating frequency range of the qubit; the second length is less than the first length.

[0245] The fifth determining submodule is used to, when the size of the superconducting quantum chip is smaller than the first length, to equate a section of readout line between the two sets of filters to a second half-wavelength resonant cavity, and to determine the length of the second half-wavelength resonant cavity to be smaller than the second length, so as to obtain the spacing between the two sets of filters.

[0246] In some embodiments, it also includes:

[0247] The building module is used to construct the circuit schematic based on the layout structure parameters of the two sets of filters;

[0248] The simulation module is used to perform circuit simulation based on the circuit schematic and obtain the circuit schematic simulation results.

[0249] The first adjustment module is used to adjust the layout structure parameters of the two sets of filters based on the frequency of the noise in the circuit principle simulation results. The noise is a signal generated by the components inside the readout module that belongs to the operating frequency range of the quantum bit and the readout cavity.

[0250] In some embodiments, the first adjustment module includes:

[0251] The noise reduction submodule is used to increase the spacing between different band-stop filters within the same filter group to reduce the noise frequency when the noise frequency is below a first frequency threshold.

[0252] In some embodiments, the first adjustment module includes:

[0253] The noise frequency enhancement submodule is used to reduce the spacing between the two sets of filters to increase the noise frequency when the noise frequency is higher than the second frequency threshold.

[0254] In some embodiments, it also includes:

[0255] The second adjustment module is used to reduce the impedance value of each filter in the two sets of filters in order to increase the bandwidth of the target isolation when there are no noise frequencies in the circuit principle simulation results and the bandwidth of the target isolation does not meet the expected bandwidth.

[0256] In some embodiments, it also includes:

[0257] The drawing module is used to draw the circuit layout based on the circuit schematic when the circuit simulation results meet the expected results; in this module, both sets of filters are drawn as curved shapes in the circuit layout.

[0258] The verification module is used for electromagnetic simulation verification based on the circuit layout.

[0259] The third determination module is used to determine the two sets of filters in the circuit layout as the final filter design results, based on the electromagnetic simulation verification results and the determination that the expected results are met.

[0260] In some embodiments, it also includes:

[0261] The third adjustment module is used to adjust the circuit layout and re-perform electromagnetic simulation verification if the electromagnetic simulation verification results do not meet the expected results, until the expected results are met.

[0262] The specific functions and examples of each module and submodule of the apparatus in this disclosure can be found in the relevant descriptions of the corresponding steps in the above method embodiments, and will not be repeated here.

[0263] According to embodiments of this disclosure, this disclosure also provides an electronic device, a readable storage medium, and a computer program product.

[0264] Figure 13 A schematic block diagram of an example electronic device 1300 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.

[0265] like Figure 13 As shown, device 1300 includes a computing unit 1301, which can perform various appropriate actions and processes according to a computer program stored in read-only memory (ROM) 1302 or a computer program loaded from storage unit 1308 into random access memory (RAM) 1303. The RAM 1303 may also store various programs and data required for the operation of device 1300. The computing unit 1301, ROM 1302, and RAM 1303 are interconnected via bus 1304. Input / output (I / O) interface 1305 is also connected to bus 1304.

[0266] Multiple components in device 1300 are connected to I / O interface 1305, including: input unit 1306, such as keyboard, mouse, etc.; output unit 1307, such as various types of monitors, speakers, etc.; storage unit 1308, such as disk, optical disk, etc.; and communication unit 1309, such as network card, modem, wireless transceiver, etc. Communication unit 1309 allows device 1300 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0267] The computing unit 1301 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of the computing unit 1301 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 1301 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 1308. In some embodiments, part or all of the computer program may be loaded and / or installed on device 1300 via ROM 1302 and / or communication unit 1309. When the computer program is loaded into RAM 1303 and executed by the computing unit 1301, 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 1301 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.

[0268] 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.

[0269] The 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.

[0270] 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.

[0271] 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).

[0272] 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.

[0273] 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.

[0274] According to embodiments of this disclosure, the electronic device can be integrated with the communication component, display screen, and information acquisition device, or it can be separately configured with the communication component, display screen, and information acquisition device.

[0275] 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.

[0276] 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: Based on the operating frequency range of the qubits in the superconducting quantum chip, the frequency parameters of the two sets of filters in the readout module of the superconducting quantum chip are determined. The readout module includes a readout cavity and a readout line. The readout cavity is coupled to the qubit. The readout module acquires information about the qubit based on the readout cavity and the readout line. Each filter group includes two band-stop filters to construct each filter group as a frequency-misalignment filter. The two filter groups are integrated on the readout line. The readout line between the two filter groups is coupled to the readout cavity so that the two filter groups are distributed on both sides of the readout cavity. The center frequencies of the two band-stop filters are different to extend the bandwidth of the frequency-misalignment filter. Based on the frequency parameters of the two sets of filters and the operating frequency range of the qubits, the layout structure parameters of the two sets of filters are determined; the layout structure parameters include the spacing between the two sets of filters, the length of each band-stop filter in the same set of filters, and the spacing between different band-stop filters in the same set of filters. Each filter group includes a first band-stop filter and a second band-stop filter; Determining the length of each band-stop filter within the same group of filters includes: The center frequency of the first band-stop filter and the center frequency of the second band-stop filter are obtained from the frequency parameters. Based on the inverse relationship between filter length and filter center frequency expressed by coplanar waveguide theory, the lengths of the first band-stop filter and the second band-stop filter are determined. Determining the spacing between different band-stop filters within the same group of filters includes: The first band-stop filter, the second band-stop filter, and a readout line between the first band-stop filter and the second band-stop filter are equivalent to a first half-wavelength resonant cavity. Based on the operating frequency range of the qubit, the center frequency of the first half-wavelength resonant cavity is determined, wherein the center frequency of the first half-wavelength resonant cavity is outside the operating frequency range of the qubit. Based on the center frequency of the first half-wavelength resonant cavity and the coplanar waveguide theory, the length of the readout line between the first band-stop filter and the second band-stop filter in the same group of filters is determined as the spacing between the different band-stop filters. The spacing between the two sets of filters is used to shift the noise generated by the read lines between the two sets of filters out of the operating frequency range of the quantum bits.

2. The method according to claim 1, wherein, The two sets of filters on the reading line are distributed in a mirror-symmetrical manner.

3. The method according to claim 2, wherein, The determination of the frequency parameters of the two sets of filters in the readout module of the superconducting quantum chip, based on the operating frequency range of the qubits in the superconducting quantum chip, includes: Based on the center frequency within the operating frequency range of the qubit, determine the respective center frequencies of the first band-stop filter and the second band-stop filter; Wherein, the frequency difference between the center frequency of the first band-stop filter and the center frequency of the second band-stop filter and the center frequency of the quantum bit is less than a first threshold; the frequency difference between the center frequency of the first band-stop filter and the center frequency of the second band-stop filter is less than a second threshold and greater than a third threshold.

4. The method according to claim 1, wherein, The determination of the readout line length between the first band-stop filter and the second band-stop filter within the same group of filters, based on the center frequency of the first half-wavelength resonant cavity and coplanar waveguide theory, includes: Based on the center frequency of the first half-wavelength resonant cavity and the coplanar waveguide theory, the total length of the first half-wavelength resonant cavity is determined. The difference between the total length of the first half-wavelength resonant cavity and the target sum is determined as the readout line length between the first band-stop filter and the second band-stop filter within the same group of filters, where the target sum is the sum of the lengths of the first band-stop filter and the second band-stop filter.

5. The method according to any one of claims 2-4, wherein, Determining the spacing between the two sets of filters includes: A section of readout line between the two sets of filters is equivalent to a second half-wavelength resonant cavity. Based on the operating frequency range of the qubit, the center frequency of the second half-wavelength resonant cavity is determined, wherein the center frequency of the second half-wavelength resonant cavity is outside the operating frequency range of the qubit. Based on the center frequency of the second half-wavelength resonant cavity and the coplanar waveguide theory, the length of the readout line between the two sets of filters is determined as the spacing between the two sets of filters.

6. The method according to any one of claims 2-4, wherein, Determining the spacing between the two sets of filters includes: Based on the lowest frequency within the operating frequency range of the qubit, determine the first length required for a third half-wavelength resonant cavity that conforms to the lowest frequency; and... Based on the highest frequency within the operating frequency range of the qubit, a second length is determined that is required for a third half-wavelength resonant cavity that meets the highest frequency; the second length is less than the first length. When the size of the superconducting quantum chip is smaller than the first length, a section of readout line between the two sets of filters is equivalent to a second half-wavelength resonant cavity, and the length of the second half-wavelength resonant cavity is determined to be smaller than the second length, so as to obtain the spacing between the two sets of filters.

7. The method according to claim 2, further comprising: The circuit schematic is constructed based on the layout structure parameters of the two sets of filters; Based on the circuit schematic, circuit simulation was performed to obtain the circuit simulation results. In the case of noise in the circuit principle simulation results, the layout structure parameters of the two sets of filters are adjusted based on the frequency of the noise. The noise is a signal generated by the components inside the readout module that belongs to the operating frequency range of the quantum bit and the readout cavity.

8. The method according to claim 7, wherein, The adjustment of the layout structure parameters of the two sets of filters based on the frequency of the spurious frequency includes: If the frequency of the noise is lower than a first frequency threshold, the spacing between different band-stop filters within the same group of filters is increased to reduce the frequency of the noise.

9. The method according to claim 7, wherein, The adjustment of the layout structure parameters of the two sets of filters based on the frequency of the spurious frequency includes: If the frequency of the noise is higher than the second frequency threshold, the spacing between the two sets of filters is reduced to increase the frequency of the noise.

10. The method according to any one of claims 7-9, further comprising: If the circuit simulation results do not show any noise and the bandwidth of the target isolation does not meet the expected bandwidth, the impedance values ​​of each filter in the two sets of filters are reduced to increase the bandwidth of the target isolation.

11. The method according to any one of claims 7-9, further comprising: If the circuit principle simulation results meet the expected results, the circuit layout is drawn based on the circuit schematic; wherein, both sets of filters are drawn as curved shapes in the circuit layout; Electromagnetic simulation verification was performed based on the circuit layout. If the electromagnetic simulation verification results confirm that the desired results are met, then the two sets of filters in the circuit layout are determined to be the final filter design results.

12. The method of claim 11, further comprising: If the electromagnetic simulation verification results do not meet the expected results, the electromagnetic simulation verification is repeated by adjusting the circuit layout until the expected results are met.

13. A superconducting quantum chip comprising the two sets of band-stop filters as determined by any one of claims 1-12.

14. An apparatus for determining a filter in a superconducting quantum chip, comprising: The first determining module is used to determine the frequency parameters of two sets of filters in the readout module of the superconducting quantum chip based on the operating frequency range of the qubits in the superconducting quantum chip. The readout module includes a readout cavity and a readout line. The readout cavity is coupled to the qubit. The readout module acquires information about the qubit based on the readout cavity and the readout line. Each set of filters includes two band-stop filters, so that each set of filters is constructed as a frequency-misalignment filter. The two sets of filters are integrated on the readout line. The readout line between the two sets of filters is coupled to the readout cavity, so that the two sets of filters are distributed on both sides of the readout cavity. The second determining module is used to determine the layout structure parameters of the two sets of filters based on the frequency parameters of the two sets of filters and the operating frequency range of the qubits; the layout structure parameters include the spacing between the two sets of filters, the length of each band-stop filter in the same set of filters, and the spacing between different band-stop filters in the same set of filters. Each of the two sets of filters includes a first band-stop filter and a second band-stop filter. The second determining module includes: An acquisition submodule is used to acquire the center frequency of the first band-stop filter and the center frequency of the second band-stop filter from the frequency parameters; The second determining submodule is used to determine the length of the first band-stop filter and the length of the second band-stop filter based on the inverse relationship between the filter length and the filter center frequency expressed by coplanar waveguide theory. The second determining module further includes: The first equivalent determination submodule is used to equate the first band-stop filter, the second band-stop filter, and a section of readout line between the first band-stop filter and the second band-stop filter to a first half-wavelength resonant cavity, and to determine the center frequency of the first half-wavelength resonant cavity based on the operating frequency range of the quantum bit, wherein the center frequency of the first half-wavelength resonant cavity is outside the operating frequency range of the quantum bit. The third determining submodule is used to determine the reading line length between the first band-stop filter and the second band-stop filter in the same group of filters as the spacing between the different band-stop filters, based on the center frequency of the first half-wavelength resonant cavity and the coplanar waveguide theory. The spacing between the two sets of filters is used to shift the noise generated by the read lines between the two sets of filters out of the operating frequency range of the quantum bits.

15. The apparatus according to claim 14, wherein, The two sets of filters on the reading line are distributed in a mirror-symmetrical manner.

16. The apparatus according to claim 15, wherein, The first determining module includes: The first determining submodule is used to determine the center frequencies of the first band-stop filter and the second band-stop filter based on the center frequencies within the operating frequency range of the qubit. Wherein, the frequency difference between the center frequency of the first band-stop filter and the center frequency of the second band-stop filter and the center frequency of the quantum bit is less than a first threshold; the frequency difference between the center frequency of the first band-stop filter and the center frequency of the second band-stop filter is less than a second threshold and greater than a third threshold.

17. The apparatus according to claim 14, wherein, The third determining submodule is specifically used for: Based on the center frequency of the first half-wavelength resonant cavity and the coplanar waveguide theory, the total length of the first half-wavelength resonant cavity is determined. The difference between the total length of the first half-wavelength resonant cavity and the target sum is determined as the readout line length between the first band-stop filter and the second band-stop filter within the same group of filters, where the target sum is the sum of the lengths of the first band-stop filter and the second band-stop filter.

18. The apparatus according to any one of claims 15-17, wherein the second determining module further comprises: The second equivalent determination submodule is used to equate a section of readout line between the two sets of filters to a second half-wavelength resonant cavity, and to determine the center frequency of the second half-wavelength resonant cavity based on the operating frequency range of the qubit, wherein the center frequency of the second half-wavelength resonant cavity is outside the operating frequency range of the qubit; The fourth determination submodule is used to determine the reading line length between the two sets of filters as the spacing between the two sets of filters based on the center frequency of the second half-wavelength resonant cavity and the coplanar waveguide theory.

19. The apparatus according to any one of claims 15-17, wherein, The second determining module further includes: A first length determination submodule is configured to determine, based on the lowest frequency within the operating frequency range of the qubit, the first length required for a third half-wavelength resonant cavity that conforms to the lowest frequency; and... The second length determination submodule is used to determine the second length required for a third half-wavelength resonant cavity that conforms to the highest frequency within the operating frequency range of the quantum bit; the second length is less than the first length. The fifth determining submodule is used to, when the size of the superconducting quantum chip is less than the first length, to equate a section of readout line between the two sets of filters to a second half-wavelength resonant cavity, and to determine the length of the second half-wavelength resonant cavity to be less than the second length, so as to obtain the spacing between the two sets of filters.

20. The apparatus according to any one of claims 15, further comprising: A construction module is used to construct a circuit schematic based on the layout structure parameters of the two sets of filters; The simulation module is used to perform circuit simulation based on the circuit schematic and obtain the circuit simulation results. The first adjustment module is used to adjust the layout structure parameters of the two sets of filters based on the frequency of the noise in the circuit principle simulation results. The noise is a signal generated by the components inside the readout module that belongs to the operating frequency range of the quantum bit and the readout cavity.

21. The apparatus according to claim 20, wherein, The first adjustment module includes: The noise reduction submodule is used to increase the spacing between different band-stop filters within the same group of filters, in order to reduce the noise frequency, when the noise frequency is lower than a first frequency threshold.

22. The apparatus according to claim 20, wherein, The first adjustment module includes: The noise frequency enhancement submodule is used to reduce the spacing between the two sets of filters to increase the noise frequency when the noise frequency is higher than a second frequency threshold.

23. The apparatus according to any one of claims 20-22, further comprising: The second adjustment module is used to reduce the impedance value of each filter in the two sets of filters in order to increase the bandwidth of the target isolation when the circuit principle simulation results do not show the noise frequency and the bandwidth of the target isolation does not meet the expected bandwidth.

24. The apparatus according to any one of claims 20-22, further comprising: The drawing module is used to draw the circuit layout based on the circuit schematic when the circuit principle simulation results meet the expected results; wherein, both sets of filters are drawn as curved shapes in the circuit layout; The verification module is used to perform electromagnetic simulation verification based on the circuit layout; The third determining module is used to determine the two sets of filters in the circuit layout as the final filter design results if the electromagnetic simulation verification results show that the expected results are met.

25. The apparatus of claim 24, further comprising: The third adjustment module is used to adjust the circuit layout and re-perform electromagnetic simulation verification if the electromagnetic simulation verification results do not meet the expected results, until the expected results are met.

26. A superconducting quantum chip comprising the two sets of band-stop filters as defined in any one of claims 14-25.

27. 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 that can be executed by the at least one processor to enable the at least one processor to perform the method of any one of claims 1-12.

28. 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 1-12.

29. A computer program product comprising a computer program that, when executed by a processor, implements the method according to any one of claims 1-12.

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