Low-temperature filtering module and quantum computer using same

Abstract

The invention 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 invention, 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] The present invention relates to the field of quantum computing technology, and in particular to a low-temperature filtering module and a quantum computer using the module. Background Art

[0002] The dilution refrigerator is the core device for achieving extremely low temperatures in quantum computers. Its function is to provide a stable millikelvin (less than approximately 10⁻³ Kelvin) operating environment for qubits to suppress the interference of thermal noise on quantum states. Within a dilution refrigerator, there are multiple temperature zones, such as the ≤20mK zone. The large number of attenuators, filters, infrared filters, and other components stacked within this ≤20mK zone results in a large space occupation, resulting in congestion in the cooling space within the millikelvin zone, which in turn affects the expansion of the number of bits.

[0003] In related technologies, in order to solve this problem, components such as attenuators, filters, and infrared filters in the mK temperature range are generally replaced with smaller components. However, due to problems such as changes in structural parameters, limited material distribution, and accumulated cascade losses, the filtering performance is reduced, the noise suppression capability is weakened, and the reliability is reduced. Summary of the Invention

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

[0005] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical solutions:

[0006] A low-temperature filter module is provided, which is used in the low-temperature range of a dilution refrigerator and includes:

[0007] Grounded housing;

[0008] A filter body, the filter body being integrated into the housing and comprising a plurality of coaxially arranged metal cylinders to form an impedance transformation structure;

[0009] The infrared absorbing structure is integrated into the shell and wrapped around the outside of the filter body.

[0010] Optionally, support plates are provided at both ends of the shell, 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 shell, the connectors are fixed on 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 connecting parts are provided at both ends of the filter body, and the connecting parts pass through the support plate and are connected to the connector.

[0015] Optionally, the infrared absorbing structure is made of infrared absorbing material, and the infrared absorbing material is filled between the inner cavity of the shell 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, an injection hole and an air outlet are opened on the surface of the shell, wherein the injection hole is used to inject the infrared absorbing material into the inner cavity of the shell, and the air outlet is used to discharge the air in the inner cavity of the shell.

[0018] Design a quantum computer, including any of the above-mentioned low-temperature filtering modules.

[0019] The beneficial effects of the present invention are as follows:

[0020] 1. The present invention integrates the low-pass filter and the infrared absorbing structure into a coaxial discontinuous metal cylindrical structure, and realizes the impedance conversion filtering and infrared quasiparticle absorption functions in parallel within the integrated module. It not only maintains the high-frequency filtering performance of the original separate devices, but also reduces the number of devices through functional integration, significantly compresses material costs and the space occupied by the mK temperature zone, alleviates the cooling pressure of the refrigerator, and eliminates the loss of cascade connectors. It improves device consistency and provides a key solution for the space expansion and reliability optimization of high-density superconducting bit systems.

[0021] 2. The present invention adopts a Teflon support plate and a copper-plated gold shell to match the thermal expansion coefficient of the low-temperature environment to prevent structural deformation. At the same time, epoxy resin is used as an infrared absorbing material with high low-temperature stability. The injection holes and air outlet holes ensure that the material is evenly filled to avoid bubble residue.

[0022] In order to more clearly illustrate the structural features and functions of the present invention, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a three-dimensional diagram of the low-temperature filter module provided by the present invention;

[0024] Figure 2 This is a three-dimensional diagram of the interior of the low-temperature filter module provided by the present invention;

[0025] Figure 3 is a cross-sectional view of a low-temperature filter module provided by the present invention;

[0026] Figure 4 This is an S-parameter curve diagram of an 8GHz low-pass filter provided by the present invention;

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

[0028] Figure 6 It is an S parameter curve diagram of the low temperature filter module provided by the present invention.

[0029] Figure numerals: 100, shell; 110, injection hole; 120, air outlet; 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 DESCRIPTION

[0030] To make the objectives, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0031] The present invention provides a low-temperature filter module and a quantum computer using the module, which solves the problem in the prior art of distributing a large number of attenuators, filters, and infrared filters in the low-temperature zone of a dilution refrigerator in a quantum computer, resulting in spatial congestion in the low-temperature zone, which in turn affects the expansion of quantum bits. To solve this problem, the prior art generally uses smaller attenuators and filters to reduce the space occupied in the low-temperature zone. Although this can alleviate the space occupation to a certain extent, the reduction in the size of the attenuators and filters will lead to a decrease in filtering performance, weakened noise suppression capability, and reduced 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, integrating the core functions of the two filters, namely low-pass filtering and infrared absorption, into the same physical structure, fundamentally reducing the number of devices and space occupancy, while also ensuring that the performance of the low-pass filter and the infrared absorbing structure after integration can reach the performance before the two filters are integrated.

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

[0034] The grounded housing 100 is a hollow structure with an internal cavity. This cavity serves as an integrated space for the low-pass filter and the infrared absorbing structure 300. The housing 100 itself also functions as a ground. The overall shape of the housing 100 is cylindrical. In other embodiments, the housing 100 may also have other shapes, such as a square.

[0035] The filter body 200 is integrated into the interior of the housing 100, and the filter body 200 includes a plurality of coaxially arranged metal cylinders, and the plurality of metal cylinders are used to form an impedance transformation structure. Specifically, the filter body 200 can be a low-pass filter, which allows signals below the cut-off frequency to pass through and suppresses signals above the cut-off frequency. In some other embodiments, the filter body 200 can also be an LC filter, which is a passive filter based on a combination of inductors and capacitors, and realizes the selective passage or suppression of signals in a specific frequency band through the reactance characteristics of inductors and capacitors. In actual applications, it can be selected according to needs. A plurality of coaxially arranged metal cylinders are connected in series with each other, and the impedance and electrical length of the metal cylinders can accurately match the prototype parameters of the low-pass filter to achieve impedance transformation, thereby achieving the function of a low-pass filter even if the structure is changed to a structure in which a plurality of metal cylinders are connected in series in order to meet the integration conditions.

[0036] The infrared absorbing structure 300 is integrated within the housing 100 and wrapped around the exterior of the filter body 200. Furthermore, the infrared absorbing structure 300 is distributed between adjacent metal cylinders of the low-pass filter, enabling both filtering functions to be implemented in parallel along the same axial length. This replaces the axial cascade of the low-pass filter and the infrared absorbing structure 300 in the prior art. This significantly reduces the device size of the low-pass filter and the infrared absorbing structure 300, lowering their footprint within the low-temperature range and enabling the expansion of more quantum bits. This also reduces the number of intermediate connectors 500 required for cascading between the low-pass filter and the infrared absorbing structure 300, effectively improving device consistency.

[0037] Optionally, support plates 400 are provided on either side of the housing 100 to support the filter body 200 and the infrared absorbing structure 300. Two support plates 400 are provided on either side of the filter body 200. Teflon can be used for these materials, which are more suitable for low temperatures and offer more stable performance. The housing 100 can be constructed of gold-plated copper. Copper and Teflon have low and well-matched thermal expansion coefficients. When cooled in the ≤20mK temperature range, the shrinkage of all components is consistent, preventing structural deformation (such as internal conductor displacement and absorbing material cracking) caused by stress concentration and ensuring impedance parameter stability.

[0038] Optionally, connectors 500 are provided at both ends of the housing 100, and the connectors 500 are fixed on the support plates 400 at both ends, and the connectors 500 are connected to the internal filter body 200 to achieve internal and external connection, thereby achieving signal transmission. The connector 500 can be an SMA connector 500 or an SMP connector 500. The SMA connector 500 is a small coaxial connector 500 with a threaded connection. The SMP connector 500 is a small radio frequency (RF) connector 500, which is widely used for signal transmission in high-frequency applications and microwave communication systems. The SMP connector 500 has a compact structure and is suitable for scenarios with limited space. The above-mentioned connector 500 does not require additional conversion devices, and is easy to integrate with the existing interfaces of cryogenic cables and superconducting bit chips, thereby reducing system adaptation costs.

[0039] Alternatively, as Figure 2 As shown, the filter body 200 includes metal cylinders of various sizes, multiple metal cylinders are coaxially arranged and connected by a metal rod 240. Connecting parts 250 are provided at both ends of the filter body 200, and the connecting parts 250 pass through the support plate 400 and are connected to the connector 500. Specifically, the multiple metal cylinders and the metal rod 240 form a "candied haws"-like structure, that is, a discontinuous cylindrical structure. The annular gaps between the "candied haws"-like cylindrical segments provide precise injection space for infrared absorbing materials. This segmented structure enables the absorbing material to evenly wrap the inner conductor, maximize the absorption path of infrared quasiparticles, and thus increase the contact area between the material and the signal transmission path. At the same time, the "candied haws"-like segmented design allows the material to absorb stress through the elastic deformation of the Teflon support when it shrinks slightly at low temperatures, thereby avoiding fracture of the rigid structure.

[0040] For example, the metal cylinders of various sizes include metal cylinder 1 210, metal cylinder 2 220, and metal cylinder 3 230. Metal cylinder 1 210 and metal cylinder 2 220 have the same length, while metal cylinder 2 220 is longer than metal cylinder 1 210 and metal cylinder 2 220. The impedance of metal cylinder 1 210 and metal cylinder 3 230 is 20Ω, while the impedance of metal cylinder 2 220 is 120Ω, which can accurately match the prototype parameters of the low-pass filter. In other embodiments, the filter body 200 includes nine metal cylinders, as shown in the following table:

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

[0042] Renewal Page

[0043] Number of sections Low-pass prototype value gi Impedance Zi (ohms) βli (degrees) 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 metal cylinder in the current section, in degrees. Zi is the impedance of the metal cylinder in the current section, in ohms. Gi is the low-pass prototype value.

[0045] Optionally, the infrared absorbing structure 300 is an infrared absorbing material that fills the inner cavity of the housing 100. The infrared absorbing material fills the inner cavity of the housing 100 and, therefore, also fills between the metal cylinders, thereby forming a coaxial radial layered structure with the metal cylinders. For example, a structure in which the metal cylinders and the infrared absorbing material alternately circulate, such as metal cylinder-infrared absorbing material-metal cylinder-infrared absorbing material-metal cylinder, enabling two filtering functions to be implemented in parallel within 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 can also be used in low-temperature environments and exhibits stable performance in such environments.

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

[0047] like Figure 4-6 As shown, Figure 4-6 is an S-curve graph, where Figure 4 This is the S parameter curve of the 8GHz low-pass filter. Figure 5 This is the S parameter curve of the infrared absorbing structure at 300 low frequency band. Figure 6It is the S parameter curve after the low-pass filter and the infrared absorbing structure 300 are integrated. The horizontal axis in the table is frequency. It represents the frequency value of the analyzed signal and is a key independent variable for studying the transmission and reflection characteristics of the filter 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 at port two when the signal is input from port one. 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 is input from port one and output at port two. dB(S(2,1)) indicates the degree of attenuation of the signal when it passes through a network such as a filter. The smaller the value, the smaller the loss during signal transmission, that is, more signals can be transmitted from the input port to the output port. From Figure 6 It can be seen from the figure that the low-temperature filter module after the low-pass filter and the infrared absorbing structure 300 are integrated can achieve the performance of the original low-pass filter and the infrared absorbing structure 300.

[0048] The present invention also provides a quantum computer comprising the above-mentioned low-temperature filtering module.

[0049] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one 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 limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A low temperature filter module, characterized in that: Applied in the low temperature range of dilution refrigerators, including: Grounded housing; A filter body, the filter body being integrated into the housing and comprising a plurality of coaxially arranged metal cylinders to form an impedance transformation structure; The infrared absorbing structure is integrated into the shell and wrapped around the outside of the filter body.

2. The low-temperature filter module according to claim 1, characterized in that: Support plates are provided at both ends of the shell, and the support plates are used to support the filter body and the infrared absorbing structure.

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

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

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

6. The low-temperature filter module according to claim 4, characterized in that: The filter body includes metal cylinders of various sizes, which are coaxially arranged and connected by a metal rod. 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 filter module according to claim 1, characterized in that: The infrared absorbing structure is made of infrared absorbing material, and the infrared absorbing material is filled between the inner cavity of the shell and the filter body.

8. The low-temperature filter 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 filter module according to claim 7, characterized in that: An injection hole and an air outlet are provided on the surface of the shell, wherein the injection hole is used to inject the infrared absorbing material into the inner cavity of the shell, and the air outlet is used to discharge the air in the inner cavity of the shell.

10. A quantum computer, characterized in that: The invention comprises the low-temperature filter module according to any one of claims 1 to 9.

Images