Low-temperature filtering module and quantum computer using same

Abstract

The utility model discloses a low-temperature filtering module and a quantum computer using the same. The low-temperature filtering module comprises a grounded shell, the filter main body is integrated in the shell, and the filter main body comprises a plurality of coaxially arranged metal cylinders to form an impedance conversion structure; the infrared wave-absorbing structure is integrated in the housing, and the infrared wave-absorbing structure wraps the filter main body. According to the utility model, the low-pass filter and the infrared wave-absorbing structure are integrally designed through a coaxial discontinuous metal cylinder structure, and impedance conversion filtering and infrared quasi-particle absorption functions are realized in parallel in an integrated module, so that the high-frequency filtering performance of an original separation device is maintained, the number of devices is reduced through function integration, and the cost is reduced. The material cost and the occupied space of the mK temperature zone are remarkably reduced, the cooling capacity pressure of a refrigerator is relieved, meanwhile, the loss of a cascade connector is eliminated, the consistency of devices is improved, and a key solution is provided for space expansion and reliability optimization of a high-density superconducting bit system.

Description

Technical Field

[0001] This utility model relates to the field of quantum computing technology, specifically to a low-temperature filtering module and a quantum computer using the module. Background Technology

[0002] The dilution refrigerator is a core component in quantum computers, responsible for achieving extremely low-temperature environments. Its function is to provide a stable milliKelvin-level (below approximately 10⁻³ Kelvin) operating environment for qubits, suppressing thermal noise interference with quantum states. However, the dilution refrigerator contains multiple temperature zones, such as ≤20 mK. The large number of attenuators, filters, infrared filters, and other components within the ≤20 mK temperature zone results in significant space constraints, leading to overcrowding of the cooling space and consequently affecting the expansion of the number of qubits.

[0003] In related technologies, to solve this problem, attenuators, filters, and infrared filters in the mK temperature range are usually replaced with smaller components. However, due to changes in structural parameters, limited material distribution, and accumulation of cascade losses, the filtering performance will decrease, the noise suppression capability will be weakened, and the reliability will be reduced. Utility Model Content

[0004] The purpose of this invention is to provide a low-temperature filtering module and a quantum computer using the module in order to solve the above problems.

[0005] To achieve the above objectives, this utility model specifically adopts the following technical solution:

[0006] This invention relates to a low-temperature filtering module, applied in the low-temperature range within a dilution refrigeration unit, comprising:

[0007] Grounded casing;

[0008] The filter body is integrated within the housing and includes multiple coaxially arranged metal cylinders to form an impedance transformation structure.

[0009] An infrared absorbing structure is integrated inside the housing and wrapped around the outside of the filter body.

[0010] Optionally, support plates are provided at both ends of the housing, and the support plates are used to support the filter body and the infrared absorbing structure.

[0011] Optionally, the support plate is made of Teflon material.

[0012] Optionally, connectors are provided at both ends of the housing, the connectors are fixed to the support plate, and the connectors are connected to the filter body.

[0013] Optionally, the connector is an SMA connector or an SMP connector.

[0014] Optionally, the filter body includes metal cylinders of various sizes, multiple metal cylinders are coaxially arranged and connected by a metal rod, and both ends of the filter body are provided with connecting parts, which pass through the support plate and are connected to the connector.

[0015] Optionally, the infrared absorbing structure is made of infrared absorbing material, which fills the space between the inner cavity of the housing and the filter body.

[0016] Optionally, the infrared absorbing material is epoxy resin, and the dielectric constant of the infrared absorbing material is 1.8-2.2.

[0017] Optionally, the surface of the housing is provided with an injection hole and an air outlet, wherein the injection hole is used to inject the infrared absorbing material into the inner cavity of the housing, and the air outlet is used to discharge the air in the inner cavity of the housing.

[0018] Design a quantum computer that includes the cryogenic filtering module described in any of the above descriptions.

[0019] The beneficial effects of this utility model are as follows:

[0020] 1. This utility model integrates a low-pass filter and an infrared absorption structure into a coaxial discontinuous metal cylindrical structure. Impedance transformation filtering and infrared quasi-particle absorption functions are implemented in parallel within the integrated module. This maintains the high-frequency filtering performance of the original discrete devices while reducing the number of devices through functional integration. This significantly reduces material costs and space occupied in the mK temperature range, alleviates the cooling pressure on the refrigerator, eliminates cascade connector losses, and improves device consistency. It provides a key solution for the spatial expansion and reliability optimization of high-density superconducting bit systems.

[0021] 2. This utility model uses a Teflon support plate and a copper-plated gold shell, with the thermal expansion coefficient matching the low-temperature environment to prevent structural deformation. At the same time, epoxy resin, as an infrared absorbing material, has high low-temperature stability, and the injection hole and vent hole ensure uniform material filling and avoid air bubble residue.

[0022] To more clearly illustrate the structural features and functions of this utility model, the following detailed description of this utility model is provided in conjunction with the accompanying drawings and specific embodiments. Attached Figure Description

[0023] Figure 1 This is a perspective view of the low-temperature filtering module provided by this utility model;

[0024] Figure 2This is a three-dimensional view of the interior of the low-temperature filtering module provided by this utility model;

[0025] Figure 3 This is a cross-sectional view of the low-temperature filtering module provided by this utility model;

[0026] Figure 4 This is a graph of the S-parameters of the 8GHz low-pass filter provided by this utility model;

[0027] Figure 5 This is a low-frequency S-parameter curve of the infrared absorbing structure provided by this utility model.

[0028] Figure 6 This is the S-parameter curve of the low-temperature filtering module provided by this utility model.

[0029] Reference numerals: 100, housing; 110, injection hole; 120, vent hole; 200, filter body; 210, metal cylinder one; 220, metal cylinder two; 230, metal cylinder three; 240, metal rod; 250, connecting part; 300, infrared absorbing structure; 400, support plate; 500, connector. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings.

[0031] This invention provides a low-temperature filter module and a quantum computer using the module, solving the problem in the prior art where a large number of attenuators, filters, and infrared filters are distributed in the low-temperature region of the dilution refrigerator in the quantum computer, causing space congestion in the low-temperature region and thus affecting the expansion of qubits. In order to solve this problem, the prior art generally uses smaller attenuators and filters to reduce the space occupied in the low-temperature region. Although this can alleviate the space occupation to a certain extent, the reduction in the size of attenuators and filters will lead to a decrease in filtering performance, a weakening of noise suppression capability, and a reduction in reliability.

[0032] The technical concept of this application is to break away from the conventional layout of cascading independent devices and design a functionally integrated structure that integrates the core functions of the two filters, namely low-pass filtering and infrared absorption, into the same physical structure. This fundamentally reduces the number of devices and space occupation, while ensuring that the performance of the integrated low-pass filter and infrared absorption structure can reach the performance of the two filters before integration.

[0033] like Figures 1-3As shown, in one embodiment, a low-temperature filtering module is applied in the low-temperature range of the dilution refrigerator within a quantum computer, specifically in the temperature range of ≤20mK. The specific structure includes:

[0034] The grounded housing 100 is a hollow structure with an internal cavity. The cavity serves as an integrated space for a low-pass filter and an infrared absorbing structure 300, and the housing 100 itself also functions as a grounding device. The housing 100 is generally cylindrical, but in some other embodiments, it may be other shapes, such as square.

[0035] The filter body 200 is integrated inside the housing 100 and includes multiple coaxially arranged metal cylinders that form an impedance transformation structure. Specifically, the filter body 200 can be a low-pass filter, allowing signals below the cutoff frequency to pass while suppressing signals above the cutoff frequency. In other embodiments, the filter body 200 can also be an LC filter, a passive filter based on a combination of inductors and capacitors, which selectively passes or suppresses signals in a specific frequency band through the reactance characteristics of the inductors and capacitors. The choice can be made according to the specific application requirements. The multiple coaxially arranged metal cylinders are connected in series, and their impedance and electrical length can be precisely matched to the prototype parameters of the low-pass filter to achieve impedance transformation. This ensures that even if the structure is changed to a series connection of multiple metal cylinders to meet integration requirements, the function of a low-pass filter can still be achieved.

[0036] The infrared absorbing structure 300 is integrated inside the housing 100 and surrounds the filter body 200. The infrared absorbing structure 300 is distributed between adjacent metal cylinders of the low-pass filter, allowing both filtering functions to be implemented in parallel along the same axial length. This replaces the axial cascading of the low-pass filter and infrared absorbing structure 300 in existing technologies, significantly reducing the device volume of both and minimizing its footprint in low-temperature environments, thus enabling the expansion of more qubits. It also reduces the need for intermediate connectors 500 between the low-pass filter and infrared absorbing structure 300, effectively improving device consistency.

[0037] Optionally, support plates 400 are provided on both sides of the housing 100. The support plates 400 are used to support the filter body 200 and the infrared absorbing structure 300. The two support plates 400 are respectively provided on both sides of the filter body 200. The support plates 400 can be made of Teflon material, which is more suitable for low temperature and has more stable performance. The housing 100 can be made of copper plated with gold. Copper and Teflon have low coefficients of thermal expansion and are compatible with each other. When cooling in the temperature range of ≤20mK, the shrinkage rate of each component is consistent, avoiding structural deformation caused by stress concentration (such as inner conductor displacement, cracking of absorbing material), and ensuring the stability of impedance parameters.

[0038] Optionally, connectors 500 are provided at both ends of the housing 100. The connectors 500 are fixed to the support plates 400 at both ends and are connected to the internal filter body 200 to achieve internal and external connection, thereby enabling signal transmission. The connectors 500 can be either SMA connectors 500 or SMP connectors 500. An SMA connector 500 is a small threaded coaxial connector 500. An SMP connector 500 is a small radio frequency (RF) connector 500, widely used in high-frequency applications and microwave communication systems for signal transmission. The SMP connector 500 has a compact structure and is suitable for space-constrained scenarios. Using these connectors 500 eliminates the need for additional conversion devices, facilitating integration with existing interfaces of cryogenic cables and superconducting bit chips, reducing system adaptation costs.

[0039] Optionally, such as Figure 2 As shown, the filter body 200 includes metal cylinders of various sizes, which are coaxially arranged and connected by a metal rod 240. Both ends of the filter body 200 have connecting portions 250 that penetrate the support plate 400 and connect to the connector 500. Specifically, the multiple metal cylinders and the metal rod 240 form a discontinuous cylindrical structure resembling a "skewer of candied hawthorns," with annular gaps between the segments providing precise injection space for the infrared absorbing material. This segmented structure allows the absorbing material to uniformly encapsulate the inner conductor, maximizing the absorption path of infrared quasi-particles and increasing the contact area between the material and the signal transmission path. Simultaneously, the segmented "skewer of candied hawthorns" design allows the material to absorb stress through the elastic deformation of the Teflon support when it contracts slightly at low temperatures, preventing rigid structural breakage.

[0040] For example, various sizes of metal cylinders include metal cylinder one 210, metal cylinder two 220, and metal cylinder three 230. Metal cylinder one 210 and metal cylinder two 220 have the same length, while metal cylinder two 220 is longer than both metal cylinder one 210 and metal cylinder two 220. Metal cylinder one 210 and metal cylinder three 230 have an impedance of 20Ω, and metal cylinder two 220 has an impedance of 120Ω, which can precisely match the prototype parameters of the low-pass filter. In some other embodiments, the filter body 200 includes nine metal cylinders, as shown in the table below:

[0041] Number of sections Low-pass prototype value gi Impedance Zi (ohms) βli (degree) 1 0.347 20 7.96

[0042] Renewal Page

[0043] Number of sections Low-pass prototype value gi Impedance Zi (ohms) βli (degree) 2 1 120 23.89 3 1.532 20 35.13 4 1.880 120 44.89 5 2 20 45.85 6 1.880 120 44.89 7 1.532 20 35.13 8 1 120 23.89 9 0.347 20 7.96

[0044] Where βli is the electrical length of the current metal cylinder segment, in degrees. Zi is the impedance of the current metal cylinder segment, in ohms. Gi is the low-pass prototype value.

[0045] Optionally, the infrared absorbing structure 300 is made of infrared absorbing material, which fills the inner cavity of the housing 100. Since the infrared absorbing material fills the inner cavity of the housing 100, it also fills the spaces between the metal cylinders, thus forming a radially layered structure coaxial with the metal cylinders. This is, for example, a structure where the metal cylinders and infrared absorbing material alternately cycle, allowing the two filtering functions to be implemented in parallel along the same axial length. The infrared absorbing material can be epoxy resin with a dielectric constant of 1.8-2.2, preferably 2.0. Epoxy resin is also suitable for use in low-temperature environments and exhibits stable performance at low temperatures.

[0046] Optionally, such as Figure 1 and Figure 3 As shown, the surface of the housing 100 is provided with an injection hole 110 and an exhaust hole 120. The injection hole 110 is used to inject infrared absorbing material into the inner cavity of the housing 100, and the exhaust hole 120 is used to expel air from the inner cavity of the housing 100. Infrared absorbing material can be injected into the inner cavity of the housing 100 through the injection hole 110. Simultaneously, during the injection process, the gas in the inner cavity can also be discharged from the exhaust hole to ensure that no air bubbles remain during low-temperature curing, avoiding a decrease in absorption efficiency due to voids. In some embodiments, there is one injection hole 110 and two exhaust holes 120. In other feasible embodiments, there can be multiple injection holes 110, such as two or three. There can also be multiple exhaust holes, such as three or four. Of course, there can also be only one exhaust hole. The specific implementation depends on the specific requirements and is not specifically limited here.

[0047] like Figure 4-6 As shown, Figure 4-6 The graph is an S-curve, where Figure 4 The S-parameter curves for an 8GHz low-pass filter are shown. Figure 5 The S-parameter curve of the infrared absorbing structure in the low-frequency band of 300 nm is shown. Figure 6 The table shows the S-parameter curves after integrating a low-pass filter with an infrared absorbing structure 300. The horizontal axis represents frequency, which is the frequency value of the analyzed signal and a key independent variable for studying the filter's transmission and reflection characteristics for signals of different frequencies. The vertical axis includes S(1,1) and S(2,1), where S(1,1) is the reflection parameter, also called the return loss parameter. It describes the reflection of a signal input at port one to port two. dB(S(1,1)) reflects the proportion of the signal reflected back to the input port; the smaller the value, the less reflected signal and the better the matching during signal transmission. S(2,1) is the transmission parameter, also called the insertion loss parameter. It describes the change in signal strength when the signal inputs at port one and outputs at port two. dB(S(2,1)) represents the attenuation of the signal as it passes through the filter and other networks; the smaller the value, the less loss occurs during signal transmission, meaning more signal can be transmitted from the input port to the output port. Figure 6 As can be seen, the low-temperature filtering module inherited from the low-pass filter and infrared absorbing structure 300 can achieve the performance of the original low-pass filter and infrared absorbing structure 300.

[0048] This invention also provides a quantum computer, including the aforementioned low-temperature filtering module.

[0049] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A low-temperature filtering module, characterized in that, Used in the low-temperature range within dilution refrigeration units, including: Grounded casing; The filter body is integrated within the housing and includes multiple coaxially arranged metal cylinders to form an impedance transformation structure. An infrared absorbing structure is integrated inside the housing and wrapped around the outside of the filter body.

2. The low-temperature filtering module according to claim 1, characterized in that, The housing is provided with support plates at both ends, which are used to support the filter body and the infrared absorbing structure.

3. The low-temperature filtering module according to claim 2, characterized in that, The support plate is made of Teflon material.

4. The low-temperature filtering module according to claim 2, characterized in that, Connectors are provided at both ends of the housing, the connectors are fixed to the support plate, and the connectors are connected to the filter body.

5. The low-temperature filtering module according to claim 4, characterized in that, The connector is an SMA connector or an SMP connector.

6. The low-temperature filtering module according to claim 4, characterized in that, The filter body includes metal cylinders of various sizes, multiple metal cylinders are coaxially arranged and connected by a metal rod, and both ends of the filter body are provided with connecting parts, which pass through the support plate and are connected to the connector.

7. The low-temperature filtering module according to claim 1, characterized in that, The infrared absorbing structure is made of infrared absorbing material, which fills the space between the inner cavity of the housing and the filter body.

8. The low-temperature filtering module according to claim 7, characterized in that, The infrared absorbing material is epoxy resin, and the dielectric constant of the infrared absorbing material is 1.8-2.

2.

9. The low-temperature filtering module according to claim 7, characterized in that, The surface of the housing is provided with an injection hole and an air outlet, wherein the injection hole is used to inject the infrared absorbing material into the inner cavity of the housing, and the air outlet is used to discharge the air in the inner cavity of the housing.

10. A quantum computer, characterized in that, Includes the low-temperature filtering module as described in any one of claims 1-9.

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