Superconductor-based coaxial cable of dilution refrigerator, dilution refrigerator, and superconducting quantum computing device

Abstract

Provided in the present invention are a superconductor-based coaxial cable of a dilution refrigerator, a dilution refrigerator, and a superconducting quantum computing device. The dilution refrigerator comprises at least a first temperature layer, a second temperature layer, a third temperature layer and a fourth temperature layer. The coaxial cable comprises a conductor layer, an insulating layer and a first shielding layer, the first shielding layer being arranged on the insulating layer at a first thickness. The coaxial cable further comprises a first coaxial cable segment disposed in the first temperature layer, a second coaxial cable segment disposed in the second temperature layer, a third coaxial cable segment disposed in the third temperature layer, and a fourth coaxial cable segment disposed in the fourth temperature layer, wherein the first thickness and the material of the parts of the first shielding layer at the first coaxial cable segment, the second coaxial cable segment, the third coaxial cable segment and the fourth coaxial cable segment are determined on the basis of a preset combination method.

Description

Coaxial cable based on superconductor-based dilution refrigerator, dilution refrigerator, and superconducting quantum computing device Technical Field

[0001] This invention relates to the technical field of dilution refrigerators, and more specifically, to a coaxial cable for a superconductor-based dilution refrigerator, the dilution refrigerator itself, and a superconducting quantum computing device. Background Technology

[0002] Superconducting quantum computing is a physical realization of quantum computing that utilizes the quantum properties of superconducting materials. Experiments in superconducting quantum computing must be conducted at extremely low temperatures (e.g., less than 20 mK). A dilution refrigerator is a key device providing ultra-low cooling for superconducting quantum computing. The dilution refrigerator has multiple stages of cold plates, which are a core component used to maintain and control the low-temperature environment. Superconducting quantum chips and various electronic devices (such as attenuators) are mounted on the cold plates, and signals are transmitted between the different stages of the cold plates via coaxial cables.

[0003] Currently, dilution refrigeration units generally use copper-nickel coaxial cables. The outermost layer of this copper-nickel coaxial cable is a copper-nickel alloy with a thickness of 0.86 mm and a thermal conductivity of 30.7 W / (m·K).

[0004] However, the inventors discovered that the copper-nickel coaxial cable inside the dilution refrigerator would generate spatial crosstalk due to the influence of spatial electromagnetic interference. Although the spatial crosstalk of existing copper-nickel coaxial cables has been controlled to the order of one-thousandth of the original signal, this level of spatial crosstalk will still have a certain impact on the calculation accuracy of superconducting quantum computing.

[0005] Therefore, the inventors believe that improving the spatial electromagnetic shielding capability of coaxial cables in dilution refrigeration machines is a technical problem that needs to be solved.

[0006] The content in the background section is merely technology known to the public and does not necessarily represent existing technology in this field. Summary of the Invention

[0007] According to one aspect of the present invention, a coaxial cable for a superconductor-based dilution refrigerator is provided. The dilution refrigerator includes at least a first temperature layer, a second temperature layer, a third temperature layer, and a fourth temperature layer. The coaxial cable includes a conductor layer, an insulating layer, and a first shielding layer, wherein the first shielding layer is disposed on the insulating layer with a first thickness. The coaxial cable includes: a first coaxial cable segment disposed in the first temperature layer; a second coaxial cable segment disposed in the second temperature layer; a third coaxial cable segment disposed in the third temperature layer; and a fourth coaxial cable segment disposed in the fourth temperature layer. The first thickness and material of the first shielding layer of the first, second, third, and fourth coaxial cable segments are determined according to a predetermined combination.

[0008] According to some embodiments of the present invention, the coaxial cable further includes: a second shielding layer disposed on the first shielding layer with a second thickness, the second shielding layer being a superconducting material. The first shielding layer is made of copper-nickel, and the second shielding layer is an immersion tin plating layer or a spray tin plating layer, with the second thickness ranging from 5 nm to 10 mm; or the first shielding layer is made of copper-nickel, and the second shielding layer is a vapor-deposited niobium layer, with the second thickness ranging from 5 nm to 10 mm.

[0009] According to some embodiments of the present invention, the preset combination method includes a first combination method, wherein the first shielding layer of the first coaxial cable segment, the second coaxial cable segment, the third coaxial cable segment, and the fourth coaxial cable segment is made of copper-nickel material. The first thickness of the first shielding layer of the first coaxial cable segment, the second coaxial cable segment, the third coaxial cable segment, and the fourth coaxial cable segment is a first characteristic thickness.

[0010] According to some embodiments of the present invention, the preset combination method includes a second combination method, wherein the first shielding layer of the first coaxial cable segment, the second coaxial cable segment, the third coaxial cable segment, and the fourth coaxial cable segment is made of beryllium copper. The first thickness of the first shielding layer of the first coaxial cable segment, the second coaxial cable segment, the third coaxial cable segment, and the fourth coaxial cable segment is a second characteristic thickness.

[0011] According to some embodiments of the present invention, the preset combination method includes a third combination method, wherein the first shielding layer of the first coaxial cable segment is made of copper-nickel material, and the first thickness of the first shielding layer of the first coaxial cable segment is a first characteristic thickness. The first shielding layers of the second, third, and fourth coaxial cable segments are made of copper-nickel material, and the first thickness of the first shielding layers of the second, third, and fourth coaxial cable segments is a second characteristic thickness. A second shielding layer with a second thickness is further provided on the first shielding layer of the second, third, and fourth coaxial cable segments. The second shielding layer is an immersion tin plating layer or a spray tin plating layer, and the second thickness ranges from 5nm to 10mm. Alternatively, the preset combination method includes a fourth combination method, wherein the first shielding layer of the first coaxial cable segment is made of copper-nickel material, and the first thickness of the first shielding layer of the first coaxial cable segment is a first characteristic thickness. The first shielding layer of the second, third, and fourth coaxial cable segments is made of copper-nickel material, and the first thickness of the first shielding layer of the second, third, and fourth coaxial cable segments is a second characteristic thickness. A second shielding layer with a second thickness is also provided on the first shielding layer of the second, third, and fourth coaxial cable segments. The second shielding layer is a vapor-deposited niobium layer, and the second thickness ranges from 5 nm to 10 mm.

[0012] According to some embodiments of the present invention, the preset combination method includes a fifth combination method, wherein: the first shielding layer of the first coaxial cable segment is made of beryllium copper, and the first thickness of the first shielding layer of the first coaxial cable segment is a second characteristic thickness. The first shielding layers of the second, third, and fourth coaxial cable segments are made of copper-nickel, and the first thickness of the first shielding layers of the second, third, and fourth coaxial cable segments is a second characteristic thickness; a second shielding layer with a second thickness is further provided on the first shielding layer of the second, third, and fourth coaxial cable segments, the second shielding layer being an immersion tin plating layer or a spray tin plating layer, and the second thickness ranging from 5nm to 10mm. Alternatively, a sixth combination can be included in the preset combination method. In this sixth combination method, the first shielding layer of the first coaxial cable segment is made of beryllium copper, and its first thickness is a second characteristic thickness. The first shielding layers of the second, third, and fourth coaxial cable segments are made of copper-nickel, and their first thicknesses are also second characteristic thicknesses. Furthermore, the first shielding layers of the second, third, and fourth coaxial cable segments are further provided with a second shielding layer of a second thickness, which is a vapor-deposited niobium layer, with a thickness ranging from 5nm to 10mm.

[0013] According to some embodiments of the present invention, the preset combination method includes a seventh combination method, wherein the first shielding layer of the first coaxial cable segment is made of copper-nickel material, and the first thickness of the first shielding layer of the first coaxial cable segment is a first characteristic thickness. The first shielding layers of the second, third, and fourth coaxial cable segments are made of niobium-titanium material, and the first thickness of the first shielding layers of the second, third, and fourth coaxial cable segments is a second characteristic thickness.

[0014] According to some embodiments of the present invention, the preset combination method includes an eighth combination method, wherein the first shielding layer of the first coaxial cable segment is made of beryllium copper, and the first thickness of the first shielding layer of the first coaxial cable segment is a second characteristic thickness. The first shielding layers of the second, third, and fourth coaxial cable segments are made of niobium-titanium, and the first thickness of the first shielding layers of the second, third, and fourth coaxial cable segments is a second characteristic thickness.

[0015] According to another aspect of the invention, a dilution refrigerator is also provided. The dilution refrigerator includes the coaxial cable as described above.

[0016] According to another aspect of the present invention, a superconducting quantum computing device is also provided. This superconducting quantum computing device includes the dilution refrigerator as described above. Beneficial effects

[0017] This invention, through a preset combination method, can determine the first thickness of the first shielding layer of each of the first, second, third, and fourth coaxial cable segments. It also determines the material of the corresponding first shielding layer for each of the first, second, third, and fourth coaxial cable segments.

[0018] With this configuration, the present invention allows for different thicknesses and materials of the first shielding layer of the coaxial cable segments in different temperature zones within the dilution refrigerator. This, based on the characteristics of the cold plate, enables the suppression of spatial crosstalk signals of varying magnitudes without significantly affecting thermal conductivity, thereby achieving overall spatial crosstalk suppression. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 shows a schematic diagram of the coaxial cable structure of the dilution refrigeration machine according to an embodiment of the present invention;

[0021] Figure 2 shows a cross-sectional schematic diagram of the coaxial cable according to an embodiment of the present invention.

[0022] Explanation of reference numerals in the attached figures:

[0023] Conductor layer 10; Insulating layer 20; First shielding layer 30; Second shielding layer 40. Embodiments of the present invention

[0024] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that the invention will be thorough and complete, and the concept of the exemplary embodiments will be fully conveyed to those skilled in the art. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted.

[0025] The described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a full understanding of embodiments of this disclosure. However, those skilled in the art will recognize that the technical solutions of this disclosure can be practiced without one or more of these specific details, or other methods, components, materials, devices, etc. In these cases, well-known structures, methods, devices, implementations, materials, or operations will not be shown or described in detail.

[0026] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0027] The terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish different objects, rather than to describe a specific order.

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Superconductors exhibit the Meissner effect, meaning that when a superconductor is cooled below its superconducting transition temperature (Tc), the magnetic flux density inside the superconductor is zero, and it can exhibit perfect diamagnetism.

[0030] The inventors discovered that due to the Meissner effect, superconductors can be used in coaxial cables of dilution refrigerators operating in cryogenic environments. Superconductor-based coaxial cables can completely eliminate resistance and repel spatial electromagnetic fields under specific low-temperature conditions, thereby improving the spatial electromagnetic shielding capability of coaxial cables in dilution refrigerators and suppressing spatial crosstalk. For example, the London penetration depth of superconductors is approximately 50-500 nm, meaning they can attenuate spatial electromagnetic fields to 1 / e of their surface area.

[0031] According to one aspect of the present invention, a coaxial cable for a superconductor-based dilution refrigerator is provided. The coaxial cable provided by the present invention has good spatial electromagnetic shielding capability and can suppress spatial crosstalk.

[0032] Figure 1 shows a schematic diagram of the coaxial cable structure of the dilution refrigeration machine according to an embodiment of the present invention.

[0033] According to an example embodiment, the dilution refrigeration unit includes at least a first temperature layer, a second temperature layer, a third temperature layer, and a fourth temperature layer.

[0034] The dilution refrigeration unit may include five cold plates, as shown in Figure 1: the first cold plate, the second cold plate, the third cold plate, the fourth cold plate, and the fifth cold plate. Different temperature zones exist between adjacent cold plates of the first, second, third, fourth, and fifth cold plates.

[0035] For example, the first cold plate can be a 50K cold plate, the second cold plate can be a 4K cold plate, the third cold plate can be a 600mK distillation layer cold plate, the fourth cold plate can be a 100mK cold plate, and the fifth cold plate can be a 10mK mixing chamber cold plate.

[0036] Figure 2 shows a cross-sectional schematic diagram of the coaxial cable according to an embodiment of the present invention.

[0037] As shown in Figure 2, the coaxial cable includes a conductor layer 10, an insulation layer 20, and a first shielding layer 30. The first shielding layer 30 has a first thickness. It is disposed on the insulating layer 20.

[0038] For example, conductor layer 10 can be composed of a single or multiple copper wires for signal transmission. Insulating layer 20 is located outside conductor layer 10 and is generally made of plastic or other insulating materials to isolate the inner and outer conductors and prevent leakage current. First shielding layer 30 is generally a mesh structure woven from metal wires for shielding interference signals.

[0039] According to an example embodiment, as shown in FIG1, the coaxial cable may include a first coaxial cable segment L1, a second coaxial cable segment L2, a third coaxial cable segment L3, and a fourth coaxial cable segment L4.

[0040] The first coaxial cable L1 is disposed in the first temperature layer formed by the first cold plate and the second cold plate, the second coaxial cable L2 is disposed in the second temperature layer formed by the second cold plate and the third cold plate, the third coaxial cable L3 is disposed in the third temperature layer formed by the third cold plate and the fourth cold plate, and the third coaxial cable L4 is disposed in the fourth temperature layer formed by the fourth cold plate and the fifth cold plate.

[0041] For example, coaxial cable segments between adjacent cold plates can be connected by a preset wiring method to form a coaxial cable as a whole.

[0042] According to the example embodiment, the first thickness of the first shielding layer 30 of the first coaxial cable segment L1, the second coaxial cable segment L2, the third coaxial cable segment L3, and the fourth coaxial cable segment L4 is... They can be different. The materials of the first shielding layer 30 of the first coaxial cable segment L1, the second coaxial cable segment L2, the third coaxial cable segment L3, and the fourth coaxial cable segment L4 can also be different.

[0043] For example, the first thickness of the first shielding layer 30 The thickness can be 0.86mm or 3.58mm. The material of the first shielding layer 30 includes, but is not limited to, copper-nickel, beryllium copper, and niobium-titanium.

[0044] By using a preset combination method, the first thickness of the first shielding layer of each of the first coaxial cable segment L1, the second coaxial cable segment L2, the third coaxial cable segment L3, and the fourth coaxial cable segment L4 can be determined. And determine the material of the corresponding first shielding layer 30 for the first coaxial cable segment L1, the second coaxial cable segment L2, the third coaxial cable segment L3 and the fourth coaxial cable segment L4.

[0045] With this configuration, the present invention allows for varying the first thickness of the first shielding layer 30 of the coaxial cable segments positioned in different temperature zones within the dilution refrigeration unit. Unlike other materials, the characteristics of cold plates allow for the suppression of spatial crosstalk signals of varying magnitudes without significantly affecting thermal conductivity, thus enabling overall suppression of spatial crosstalk.

[0046] Optionally, as shown in Figure 2, the coaxial cable may further include a second shielding layer 40. The second shielding layer 40 has a second thickness. It is installed on the first shielding layer 30.

[0047] Optionally, the first shielding layer 30 is made of copper-nickel material, and the second shielding layer 40 is a tin-plated layer or a tin-sprayed layer, with a second thickness... The range is 5nm-10mm. Preferably, the second thickness... The range is 100nm-10um.

[0048] According to experimental data from the present invention, the thermal conductivity of tin is 60 W / (m·K), and the second thickness of the immersion tin plating or spray tin plating is... Insufficient first thickness of copper-nickel first shielding layer One percent of the heat transfer per unit volume can be significantly reduced. Furthermore, the superconducting transition temperature is 3.72 K. After the superconducting transition, the resistance of the tin plating layer is zero and it exhibits the Meissner effect, thus suppressing electromagnetic crosstalk in space.

[0049] Optionally, the first shielding layer 30 is made of copper-nickel material, and the second shielding layer 40 is a vapor-deposited niobium layer with a second thickness. The range is 5nm-10mm. Preferably, the second thickness... The range is 100nm-10um.

[0050] The niobium layer can be deposited on the first shielding layer 30 by magnetron sputtering.

[0051] Experimental data according to the present invention show that niobium has a lower thermal conductivity, such as 53.7 W / (m·K). The second thickness of the vapor-deposited niobium layer... At the level of hundreds of nanometers or even micrometers, the thermal conductivity per unit volume can be significantly suppressed. At this point, the superconducting transition temperature is 9.2 K, and based on the superconducting properties of niobium, electromagnetic crosstalk in space can also be suppressed.

[0052] Optionally, the preset combination method includes a first combination method, which is:

[0053] The first shielding layer 30 of the first coaxial cable segment L1, the second coaxial cable segment L2, the third coaxial cable segment L3, and the fourth coaxial cable segment L4 is made of copper-nickel material. The first thickness of the first shielding layer 30 of the first coaxial cable segment L1, the second coaxial cable segment L2, the third coaxial cable segment L3, and the fourth coaxial cable segment L4 is... The thickness is the first characteristic.

[0054] For example, the thickness of the first feature is 3.58 mm.

[0055] For example, the thickness of copper-nickel coaxial cables in the prior art is 0.86 mm, while the first thickness of the copper-nickel first shielding layer in this invention is... It is 3.58mm.

[0056] According to the experimental data of the present invention, the resistivity of a 3.58mm copper-nickel coaxial cable is 0.27Ω / m@300K, while the resistivity of a 0.86mm copper-nickel coaxial cable is 1.56Ω / m@300K. The first combination can be referred to Table (1):

[0057] Table (1)

[0058]

[0059] This invention reduces the resistivity of the coaxial cable by adjusting its thickness, thereby reducing the introduction of electromagnetic crosstalk.

[0060] It is understandable that the skin effect indicates that the thicker the metal layer, the stronger the electromagnetic shielding capability. In the single coaxial cable experiment of this invention, compared with the 0.86mm copper-nickel coaxial cable, a significant electromagnetic crosstalk suppression effect can be seen in the 3.58mm copper-nickel coaxial cable, such as a noise reduction of about 3dB.

[0061] According to the example embodiment, an initial coaxial cable segment L0 can also be set between the room temperature layers. However, the initial coaxial cable segment L0 and the first coaxial cable segment L1 are made of the same material. Therefore, the initial coaxial cable segment L0 and the first coaxial cable segment L1 can be regarded as the same cable segment. The present invention does not limit this.

[0062] Optionally, the preset combination method includes a second combination method, which is:

[0063] The first shielding layer 30 of the first coaxial cable segment L1, the second coaxial cable segment L2, the third coaxial cable segment L3, and the fourth coaxial cable segment L4 is made of beryllium copper. The first thickness of the first shielding layer 30 of the first coaxial cable segment L1, the second coaxial cable segment L2, the third coaxial cable segment L3, and the fourth coaxial cable segment L4 is... The thickness is the second feature.

[0064] For example, the thickness of the second feature can be 0.86 mm.

[0065] For the second combination method, please refer to Table (2):

[0066] Table (2)

[0067]

[0068] For example, experimental data according to the present invention shows that the resistivity of the beryllium copper first shielding layer is 0.39 Ω / m@300K, and the beryllium copper first shielding layer can also reduce the introduction of electromagnetic crosstalk. In the low-temperature comparative experiment of the present invention, with all cables being 0.86 mm copper-nickel coaxial cables, the electromagnetic crosstalk signal strength was -56 dB. However, in the second combination provided by the present invention, the electromagnetic crosstalk signal was suppressed below the system noise, at which point the system noise was -80.7 dB.

[0069] Optionally, the preset combination method includes a third combination method, which is:

[0070] The first coaxial cable segment L1 is made of copper-nickel material. The first shielding layer of the first coaxial cable segment L1 has a first thickness of 30. The first characteristic thickness is specified. The first shielding layer of the second coaxial cable segment L2, the third coaxial cable segment L3, and the fourth coaxial cable segment L4 is made of copper-nickel material, and the first thickness of the first shielding layer 30 of the second coaxial cable segment L2, the third coaxial cable segment L3, and the fourth coaxial cable segment L4 is specified. The thickness is the second feature.

[0071] The first shielding layer 30 of the second coaxial cable segment L2, the third coaxial cable segment L3, and the fourth coaxial cable segment L4 is provided with a second thickness. The second shielding layer 40. The second shielding layer 40 is a tin-immersion plating layer or a tin-sprayed plating layer, with a second thickness. The range is 5nm-10mm. Preferably, the second thickness... The range is 100nm-10um.

[0072] Taking the first feature thickness as 3.58 mm and the second feature thickness as 0.86 mm as an example, the third combination method can be referred to Table (3):

[0073] Table (3)

[0074]

[0075] According to the example embodiment, the tin plating layer can be an immersion tin plating layer or a spray tin plating layer, and the present invention does not limit this.

[0076] According to the experimental data of the present invention, taking the tin-plated layer as an example, the thickness of the tin-plated layer is 3.2275 μm. In the low-temperature comparative experiment of the present invention, with all cables being 0.86 mm copper-nickel coaxial cables, the electromagnetic crosstalk signal strength is -56 dB. However, in the third combination method provided by the present invention, the electromagnetic crosstalk signal is suppressed below the system noise, at which point the system noise is approximately -81.4 dB.

[0077] Optionally, the preset combination method includes a fourth combination method, which is:

[0078] The first shielding layer 30 of the first coaxial cable segment L1 is made of copper-nickel material, and the first thickness of the first shielding layer 30 of the first coaxial cable segment L1 is... The first characteristic thickness is specified. The first shielding layer 30 of the second coaxial cable segment L2, the third coaxial cable segment L3, and the fourth coaxial cable segment L4 is made of copper-nickel material. The first thickness of the first shielding layer 30 of the second coaxial cable segment L2, the third coaxial cable segment L3, and the fourth coaxial cable segment L4 is specified. The thickness is the second feature.

[0079] The first shielding layer 30 of the second coaxial cable segment L2, the third coaxial cable segment L3, and the fourth coaxial cable segment L4 is provided with a second thickness. The second shielding layer 40. The second shielding layer 40 is a vapor-deposited niobium layer, with a second thickness. The range is 5nm-10mm. Preferably, the second thickness... The range is 100nm-10um.

[0080] Taking the thickness of the first feature as 3.58 mm and the thickness of the second feature as 0.86 mm as an example, the fourth combination method can be referred to Table (4):

[0081] Table (4)

[0082]

[0083] Based on the same principle as the third combination method, this setting can suppress electromagnetic crosstalk signals, and its suppression of spatial electromagnetic crosstalk is better than that of traditional copper-nickel cables.

[0084] Optionally, the preset combination method includes a fifth combination method, which is:

[0085] The first shielding layer 30 of the first coaxial cable segment L1 is made of beryllium copper, and the first thickness of the first shielding layer 30 of the first coaxial cable segment L1 is... The second characteristic thickness. The first shielding layer 30 of the second coaxial cable segment L2, the third coaxial cable segment L3, and the fourth coaxial cable segment L4 is made of copper-nickel material, and the first thickness of the first shielding layer 30 of the second coaxial cable segment L2, the third coaxial cable segment L3, and the fourth coaxial cable segment L4 is... The thickness is the second feature.

[0086] The first shielding layer 30 of the second coaxial cable segment L2, the third coaxial cable segment L3, and the fourth coaxial cable segment L4 is provided with a second thickness. The second shielding layer 40. The second shielding layer 40 is a tin-immersion plating layer or a tin-sprayed plating layer, with a second thickness. The range is 5nm-10mm. Preferably, the second thickness... The range is 100nm-10um.

[0087] For example, the fifth combination method can be referred to Table (5):

[0088] Table (5)

[0089]

[0090] Based on the same principle as the third combination method, this setting can suppress electromagnetic crosstalk signals, and its suppression of spatial electromagnetic crosstalk is better than that of traditional copper-nickel cables.

[0091] Optionally, the preset combination method includes a sixth combination method, which is:

[0092] The first shielding layer 30 of the first coaxial cable segment L1 is made of beryllium copper, and the first thickness of the first shielding layer 30 of the first coaxial cable segment L1 is... The second characteristic thickness. The first shielding layer 30 of the second coaxial cable segment L2, the third coaxial cable segment L3, and the fourth coaxial cable segment L4 is made of copper-nickel material, and the first thickness of the first shielding layer 30 of the second coaxial cable segment L2, the third coaxial cable segment L3, and the fourth coaxial cable segment L4 is... The thickness is the second feature.

[0093] The first shielding layer 30 of the second coaxial cable segment L2, the third coaxial cable segment L3, and the fourth coaxial cable segment L4 is provided with a second thickness. The second shielding layer 40. The second shielding layer 40 is a vapor-deposited niobium layer, with a second thickness. The range is 5nm-10mm. Preferably, the second thickness... The range is 100nm-10um.

[0094] Taking the second feature thickness of 0.86mm as an example, the sixth combination method can be referred to Table (6):

[0095] Table (6)

[0096]

[0097] Based on the same principle as the third combination method, this setting can suppress electromagnetic crosstalk signals, and its suppression of spatial electromagnetic crosstalk is better than that of traditional copper-nickel cables.

[0098] Optionally, the preset combination method includes a seventh combination method, which is:

[0099] The first shielding layer 30 of the first coaxial cable segment L1 is made of copper-nickel material, and the first thickness of the first shielding layer 30 of the first coaxial cable segment L1 is... The first characteristic thickness is specified. The first shielding layer 30 of the second coaxial cable segment L2, the third coaxial cable segment L3, and the fourth coaxial cable segment L4 is made of niobium-titanium material, and the first thickness of the first shielding layer 30 of the second coaxial cable segment L2, the third coaxial cable segment L3, and the fourth coaxial cable segment L4 is specified. The thickness is the second feature.

[0100] Taking a first feature thickness of 3.58 mm and a second feature thickness of 0.86 mm as an example, the seventh combination method can be found in Table (7):

[0101] Table (7)

[0102]

[0103] In the low-temperature comparative experiment of this invention, with all cables being 0.86mm copper-nickel coaxial cables, the electromagnetic crosstalk signal strength was -56dB. However, in the seventh combination method provided by this invention, the electromagnetic crosstalk signal was suppressed below the system noise level, at which point the system noise was approximately -75.9dB.

[0104] Optionally, the preset combination method includes an eighth combination method, which is:

[0105] The first shielding layer 30 of the first coaxial cable segment L1 is made of beryllium copper, and the first thickness of the first shielding layer 30 of the first coaxial cable segment L1 is... The second characteristic thickness. The first shielding layer 30 of the second coaxial cable segment L2, the third coaxial cable segment L3, and the fourth coaxial cable segment L4 is made of niobium-titanium material, and the first thickness of the first shielding layer 30 of the second coaxial cable segment L2, the third coaxial cable segment L3, and the fourth coaxial cable segment L4 is... The thickness is the second feature.

[0106] For example, the seventh combination method can be referred to Table (8):

[0107] Table (8)

[0108]

[0109] Based on the same principle as the first, third, and seventh combination methods, this configuration can suppress electromagnetic crosstalk signals, and its suppression of spatial electromagnetic crosstalk is superior to that of traditional copper-nickel cables.

[0110] According to another aspect of the invention, a dilution refrigerator is also provided. The dilution refrigerator includes the coaxial cable as described above.

[0111] According to another aspect of the present invention, a superconducting quantum computing device is also provided. This superconducting quantum computing device includes the dilution refrigerator as described above.

[0112] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions of the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A coaxial cable for a superconductor-based dilution refrigerator, characterized in that, The dilution refrigeration unit includes at least a first temperature layer, a second temperature layer, a third temperature layer and a fourth temperature layer, and the coaxial cable includes a conductor layer, an insulation layer and a first shielding layer, wherein the first shielding layer is disposed on the insulation layer with a first thickness; The coaxial cable includes: The first coaxial cable segment is disposed in the first temperature layer; The second coaxial cable segment is disposed in the second temperature layer; The third coaxial cable segment is disposed in the third temperature layer; The fourth coaxial cable segment is disposed in the fourth temperature layer; The first thickness and material of the first shielding layer of the first coaxial cable segment, the second coaxial cable segment, the third coaxial cable segment, and the fourth coaxial cable segment are determined according to a preset combination method.

2. The coaxial cable according to claim 1, characterized in that, The coaxial cable also includes: A second shielding layer is disposed on the first shielding layer with a second thickness, and the second shielding layer is a superconducting material. Wherein, the first shielding layer is made of copper-nickel material, the second shielding layer is an immersion tin plating layer or a spray tin plating layer, and the second thickness ranges from 5nm to 10mm; or the first shielding layer is made of copper-nickel material, the second shielding layer is a vapor-deposited niobium layer, and the second thickness ranges from 5nm to 10mm.

3. The coaxial cable according to claim 1, characterized in that, The preset combination method includes a first combination method, which is: The first shielding layer of the first coaxial cable segment, the second coaxial cable segment, the third coaxial cable segment, and the fourth coaxial cable segment is made of copper-nickel material; The first thickness of the first shielding layer of the first coaxial cable segment, the second coaxial cable segment, the third coaxial cable segment, and the fourth coaxial cable segment is the first characteristic thickness.

4. The coaxial cable according to claim 1, characterized in that, The preset combination method includes a second combination method, which is: The first shielding layer of the first coaxial cable segment, the second coaxial cable segment, the third coaxial cable segment, and the fourth coaxial cable segment is made of beryllium copper. The first thickness of the first shielding layer of the first coaxial cable segment, the second coaxial cable segment, the third coaxial cable segment, and the fourth coaxial cable segment is the second characteristic thickness.

5. The coaxial cable according to claim 1, characterized in that, The preset combination method includes a third combination method, which is: The first shielding layer of the first coaxial cable segment is made of copper-nickel material, and the first thickness of the first shielding layer of the first coaxial cable segment is the first characteristic thickness. The first shielding layer of the second coaxial cable segment, the third coaxial cable segment, and the fourth coaxial cable segment is made of copper-nickel material, and the first thickness of the first shielding layer of the second coaxial cable segment, the third coaxial cable segment, and the fourth coaxial cable segment is a second characteristic thickness; The first shielding layer of the second coaxial cable segment, the third coaxial cable segment and the fourth coaxial cable segment are further provided with a second shielding layer with a second thickness. The second shielding layer is an immersion tin plating layer or a spray tin plating layer, and the second thickness ranges from 5nm to 10mm. or The preset combination method includes a fourth combination method, which is: The first shielding layer of the first coaxial cable segment is made of copper-nickel material, and the first thickness of the first shielding layer of the first coaxial cable segment is the first characteristic thickness. The first shielding layer of the second coaxial cable segment, the third coaxial cable segment, and the fourth coaxial cable segment is made of copper-nickel material, and the first thickness of the first shielding layer of the second coaxial cable segment, the third coaxial cable segment, and the fourth coaxial cable segment is a second characteristic thickness; The first shielding layer of the second coaxial cable segment, the third coaxial cable segment and the fourth coaxial cable segment are further provided with a second shielding layer with a second thickness. The second shielding layer is a vapor-deposited niobium layer and the second thickness ranges from 5nm to 10mm.

6. The coaxial cable according to claim 1, characterized in that, The preset combination method includes a fifth combination method, which is: The first shielding layer of the first coaxial cable segment is made of beryllium copper, and the first thickness of the first shielding layer of the first coaxial cable segment is the second characteristic thickness; The first shielding layer of the second coaxial cable segment, the third coaxial cable segment, and the fourth coaxial cable segment is made of copper-nickel material, and the first thickness of the first shielding layer of the second coaxial cable segment, the third coaxial cable segment, and the fourth coaxial cable segment is a second characteristic thickness; The first shielding layer of the second coaxial cable segment, the third coaxial cable segment and the fourth coaxial cable segment are further provided with a second shielding layer with a second thickness. The second shielding layer is an immersion tin plating layer or a spray tin plating layer, and the second thickness ranges from 5nm to 10mm. or The preset combination method includes a sixth combination method, which is: The first shielding layer of the first coaxial cable segment is made of beryllium copper, and the first thickness of the first shielding layer of the first coaxial cable segment is the second characteristic thickness; The first shielding layer of the second, third, and fourth coaxial cable segments is made of copper-nickel material, and the first thickness of the first shielding layer of the second, third, and fourth coaxial cable segments is a second characteristic thickness; a second shielding layer with a second thickness is also provided on the first shielding layer of the second, third, and fourth coaxial cable segments, the second shielding layer being a vapor-deposited niobium layer, and the second thickness ranging from 5nm to 10mm.

7. The coaxial cable according to claim 1, characterized in that, The preset combination method includes a seventh combination method, which is: The first shielding layer of the first coaxial cable segment is made of copper-nickel material, and the first thickness of the first shielding layer of the first coaxial cable segment is the first characteristic thickness. The first shielding layer of the second, third, and fourth coaxial cable segments is made of niobium-titanium material, and the first thickness of the first shielding layer of the second, third, and fourth coaxial cable segments is the second characteristic thickness.

8. The coaxial cable according to claim 1, characterized in that, The preset combination method includes an eighth combination method, which is: The first shielding layer of the first coaxial cable segment is made of beryllium copper, and the first thickness of the first shielding layer of the first coaxial cable segment is the second characteristic thickness; The first shielding layer of the second, third, and fourth coaxial cable segments is made of niobium-titanium material, and the first thickness of the first shielding layer of the second, third, and fourth coaxial cable segments is the second characteristic thickness.

9. A dilution refrigeration machine, characterized in that, Including the coaxial cable as described in any one of claims 1-8.

10. A superconducting quantum computing device, characterized in that, Includes the dilution refrigeration unit as described in claim 9.

Images