CN-117574824-B - Method, device and related equipment for determining filter in superconducting quantum chip

Abstract

The disclosure provides a method, a device and related equipment for determining a filter in a superconducting quantum chip, relates to the technical field of quantum computing, and particularly relates to the technical field of superconducting quantum chips. The method comprises the steps of determining center frequencies of two band-stop filters based on the center frequency of quantum bits of a superconducting quantum chip, determining lengths of the two band-stop filters based on the center frequencies of the two band-stop filters, and determining the length of a target line segment of a reading line between the two band-stop filters as the distance between the two band-stop filters based on the working frequency range of the quantum bits, wherein the two band-stop filters are connected with the reading line, and the reading line between the two band-stop filters is coupled with a reading cavity so that the two band-stop filters are distributed on two sides of the reading cavity. In the embodiment of the disclosure, based on the central frequency of the quantum bit, key parameters of the band-stop filter can be designed to improve the decoherence time of the quantum bit, and the whole flow is simple and convenient to design and easy to realize.

Inventors

• Wei Yuanbang
• WANG YUXUAN
• JIN LIJING

Assignees

• 北京百度网讯科技有限公司

Dates

Publication Date

20260512

Application Date

20231117

Claims (20)

1. 1. A method of determining a filter in a superconducting quantum chip, comprising: The reading module of the superconducting quantum chip comprises a reading cavity and a reading line, wherein the two band-stop filters are integrated on the reading line, and the reading cavity is coupled with the quantum bit so that the reading module obtains the state of the quantum bit based on the reading cavity and the reading line; determining the lengths of the two band-stop filters based on coplanar waveguide theory and the center frequencies of the two band-stop filters, and And determining the length of a target line segment of the reading line between the two band-stop filters as the distance between the two band-stop filters based on a coplanar waveguide theory and the working frequency range of the quantum bit, wherein the center frequency of a half-wavelength resonant cavity equivalent to the target line segment is out of the working frequency range of the quantum bit, the two band-stop filters are connected with the reading line, and the reading line between the two band-stop filters is coupled with the reading cavity so that the two band-stop filters are distributed on two sides of the reading cavity.
2. 2. The method of claim 1, wherein the determining the center frequencies of the two band reject filters based on the center frequencies of the qubits of the superconducting quantum chip comprises: And selecting the center frequencies of the two band-stop filters within a preset range taking the center frequency of the qubit as a reference.
3. 3. The method of claim 1 or 2, further comprising: Determining an initial design layout integrating the two band-stop filters on the reading line based on the length of a target line segment between the two band-stop filters and the length of the two band-stop filters; simulating the initial design layout to obtain a simulation result; And under the condition that the simulation result accords with a preset condition, determining the initial design layout as a target design layout of the integrated band-stop filter, wherein the preset condition is that the working frequency range of the quantum bit is free of mixed frequency, and the central frequencies of the two band-stop filters are in the working frequency range of the quantum bit.
4. 4. A method according to claim 3, further comprising: Under the condition that the simulation result does not accord with the preset condition, adjusting parameters of the two band-stop filters in the initial design layout based on the problem category in the simulation result; and performing simulation verification based on the adjusted initial design layout until a final simulation result meets the preset condition.
5. 5. The method of claim 4, wherein the adjusting parameters of the two bandstop filters in the initial design layout based on the problem category in the simulation result comprises: and under the condition that the problem category in the simulation result is that the mixed frequency is generated in the working frequency range of the quantum bit, the segment length of the target segment between the two band-stop filters is adjusted so as to eliminate the mixed frequency.
6. 6. The method of claim 5, wherein the adjusting the segment length of the target segment between the two band-stop filters to eliminate the mixed frequency in the case that the problem category in the simulation result is that the mixed frequency is generated in the operating frequency range of the qubit comprises: reducing the segment length of the target segment under the condition that the frequency of the mixed frequency is higher than a first frequency threshold value; And increasing the length of the target line segment under the condition that the frequency of the impurity frequency is lower than a second frequency threshold value, wherein the second frequency threshold value is smaller than the first frequency threshold value.
7. 7. The method of claim 4, wherein the adjusting parameters of the two bandstop filters in the initial design layout based on the problem category in the simulation result comprises: And when the problem category in the simulation result is that the frequency difference between the simulation frequency of the two band-stop filters and the center frequency of the two band-stop filters is larger than a preset frequency difference, adjusting the lengths of the two band-stop filters so that the frequency difference is smaller than the preset frequency difference.
8. 8. The method of claim 7, wherein the adjusting the lengths of the two band reject filters such that the frequency difference is less than the preset frequency difference comprises: Reducing the lengths of the two band-stop filters so that the frequency difference is smaller than the preset frequency difference under the condition that the simulation frequency of the two band-stop filters is smaller than the center frequency of the two band-stop filters; And under the condition that the simulation frequency of the two band-stop filters is larger than the center frequency of the two band-stop filters, the lengths of the two band-stop filters are increased so that the frequency difference is smaller than the preset frequency difference.
9. 9. A method according to claim 3, wherein an air bridge is erected at the junction of the two band reject filters and the read line in the initial design layout.
10. 10. A method according to claim 3, further comprising: on the basis of obtaining the target design layout, additionally performing electromagnetic simulation verification on the target design layout at least once to obtain a verification result; and under the condition that the verification result meets the preset condition, determining the target design layout as the final design layout of the integrated band elimination filter.
11. 11. A superconducting quantum chip comprising the two bandstop filters designed according to the method of any of claims 1-10.
12. 12. An apparatus for determining a filter in a superconducting quantum chip, comprising: The frequency determining module is used for determining the center frequencies of the two band-stop filters based on the center frequency of the quantum bit of the superconducting quantum chip; the reading module of the superconducting quantum chip comprises a reading cavity and a reading line, wherein the two band-stop filters are integrated on the reading line and are coupled with the quantum bit so as to enable the reading module to acquire the state of the quantum bit based on the reading cavity and the reading line; a length determining module for determining the lengths of the two band-stop filters based on the coplanar waveguide theory and the center frequencies of the two band-stop filters, and The distance determining module is used for determining the length of a target line segment of the reading line between the two band-stop filters as the distance between the two band-stop filters based on a coplanar waveguide theory and the working frequency range of the quantum bit, wherein the center frequency of a half-wavelength resonant cavity equivalent to the target line segment is out of the working frequency range of the quantum bit, the two band-stop filters are connected with the reading line, and the reading line between the two band-stop filters is coupled with the reading cavity so that the two band-stop filters are distributed on two sides of the reading cavity.
13. 13. The apparatus of claim 12, wherein the frequency determination module is configured to: And selecting the center frequencies of the two band-stop filters within a preset range taking the center frequency of the qubit as a reference.
14. 14. The apparatus of claim 12 or 13, further comprising a simulation module configured to: The first determining unit is used for determining an initial design layout integrating the two band-stop filters on the reading line based on the length of a target line segment between the two band-stop filters and the length of the two band-stop filters; the simulation unit is used for simulating the initial design layout to obtain a simulation result; And the second determining unit is used for determining the initial design layout as the target design layout of the integrated band-stop filter under the condition that the simulation result accords with the preset condition, wherein the preset condition is that the working frequency range of the quantum bit is free from mixed frequency, and the central frequencies of the two band-stop filters are in the working frequency range of the quantum bit.
15. 15. The apparatus of claim 14, further comprising an adjustment module to: The adjusting unit is used for adjusting parameters of the two band-stop filters in the initial design layout based on the problem category in the simulation result under the condition that the simulation result does not accord with the preset condition; and the verification unit is used for performing simulation verification based on the adjusted initial design layout until the final simulation result meets the preset condition.
16. 16. The apparatus of claim 15, wherein the adjustment unit is configured to: and under the condition that the problem category in the simulation result is that the mixed frequency is generated in the working frequency range of the quantum bit, the segment length of the target segment between the two band-stop filters is adjusted so as to eliminate the mixed frequency.
17. 17. The apparatus of claim 16, wherein the adjustment unit is configured to: reducing the segment length of the target segment under the condition that the frequency of the mixed frequency is higher than a first frequency threshold value; And increasing the length of the target line segment under the condition that the frequency of the impurity frequency is lower than a second frequency threshold value, wherein the second frequency threshold value is smaller than the first frequency threshold value.
18. 18. The apparatus of claim 15, wherein the adjustment unit is configured to: And when the problem category in the simulation result is that the frequency difference between the simulation frequency of the two band-stop filters and the center frequency of the two band-stop filters is larger than a preset frequency difference, adjusting the lengths of the two band-stop filters so that the frequency difference is smaller than the preset frequency difference.
19. 19. The apparatus of claim 18, wherein the adjustment unit is configured to: Reducing the lengths of the two band-stop filters so that the frequency difference is smaller than the preset frequency difference under the condition that the simulation frequency of the two band-stop filters is smaller than the center frequency of the two band-stop filters; And under the condition that the simulation frequency of the two band-stop filters is larger than the center frequency of the two band-stop filters, the lengths of the two band-stop filters are increased so that the frequency difference is smaller than the preset frequency difference.
20. 20. The apparatus of claim 14, wherein an air bridge is erected at a junction of the two band reject filters and the read line in the initial design layout.

Description

Method, device and related equipment for determining filter in superconducting quantum chip Technical Field The disclosure relates to the field of quantum computing technology, and in particular to the technical field of superconducting quantum chips. Background A complete superconducting quantum chip needs to contain various functional modules, such as a reading module, a wiring module, a quantum bit and coupling module and the like. Of these modules, the reading module is the functional module first involved in the actual measurement process, and therefore the design of the module is important. The equivalent qubit jumps from a high energy level to a low energy level, and due to the coupling between the qubit and the reading cavity, a transition photon has a certain probability to enter the reading cavity, so that the reading cavity is in an excited state. In addition, since the reading cavity is directly coupled with external loss (excitation), the reading cavity in the excited state has a certain probability of transition to the ground state, so that the energy of the qubit is leaked. Therefore, it is desirable to design filters to reduce leakage of qubit energy and improve decoherence time of the qubit. Disclosure of Invention The present disclosure provides a method, apparatus, and related device for determining a filter in a superconducting quantum chip. According to an aspect of the present disclosure, there is provided a method of determining a filter in a superconducting quantum chip, comprising: The reading module of the superconducting quantum chip comprises a reading cavity and a reading line, wherein the two band-stop filters are integrated on the reading line and are coupled with the quantum bit so that the reading module obtains the state of the quantum bit based on the reading cavity and the reading line; determining the lengths of the two band-stop filters based on the center frequencies of the two band-stop filters, and And determining the length of a target line segment of the reading line between the two band-stop filters as the distance between the two band-stop filters based on the working frequency range of the qubit, wherein the two band-stop filters are connected with the reading line, and the reading line between the two band-stop filters is coupled with the reading cavity so that the two band-stop filters are distributed on two sides of the reading cavity. According to another aspect of the present disclosure, there is provided an apparatus for determining a filter in a superconducting quantum chip, comprising: The device comprises a frequency determining module, a reading module, a frequency adjusting module and a frequency adjusting module, wherein the frequency determining module is used for determining the center frequency of two band-stop filters based on the center frequency of a quantum bit of a superconducting quantum chip; a length determining module for determining the lengths of the two band-stop filters based on the center frequencies of the two band-stop filters, and The distance determining module is used for determining the length of a target line segment of the reading line between the two band-stop filters as the distance between the two band-stop filters based on the working frequency range of the quantum bit, wherein the two band-stop filters are connected with the reading line, and the reading line between the two band-stop filters is coupled with the reading cavity so that the two band-stop filters are distributed on two sides of the reading cavity. According to another aspect of the present disclosure, there is provided a superconducting quantum chip comprising two band-stop filters designed by the method of any of the embodiments of the present disclosure. According to another aspect of the present disclosure, there is provided an electronic device including: at least one processor, and A memory communicatively coupled to the at least one processor, wherein, The memory stores instructions executable by the at least one processor to enable the at least one processor to perform the method of any one of the embodiments of the present disclosure. According to another aspect of the present disclosure, there is provided a non-transitory computer-readable storage medium storing computer instructions for causing the computer to perform a method according to any one of the embodiments of the present disclosure. According to another aspect of the present disclosure, there is provided a computer program product comprising a computer program which, when executed by a processor, implements a method according to any of the embodiments of the present disclosure. In the embodiment of the disclosure, key parameters of the band-stop filter can be designed based on the center frequency of the quantum bit, wherein the key parameters comprise the center frequency of the band-stop filter and the interval between the center frequency and the interval to improve the decoherence ti