Cryogenic filter modules for scalable quantum computing architectures

Abstract

One or more systems, devices, and / or methods of use provided herein relate to signal filters for scalable quantum computing architectures. According to one embodiment, a device may have a circuit board including multiple layers, where various ones of the multiple layers include different absorbent materials, and multiple signal lines passing through the circuit board, where a first layer of the circuit board is composed of a first material that filters a first signal line traversing through at least the first layer of the multiple layers (FIG. 1).

Description

[Background technology]

[0001] The present disclosure relates to signal filters, and more particularly to cryogenic filter modules for scalable quantum computing architectures. Summary of the Invention

[0002] The following presents a summary to provide a basic understanding of one or more embodiments of the invention. This summary is not intended to identify key or critical elements or to delineate the scope of any particular embodiments or the claims. Its sole purpose is to present concepts in a simplified form as a prelude to the more detailed description that is presented later. In one or more embodiments described herein, devices, systems, and apparatuses that facilitate the operation, design, and / or manufacture of cryogenic filter modules for scalable quantum computing architectures are described.

[0003] According to one embodiment, a system may include a device, wherein the device has a circuit board including multiple layers, wherein various ones of the multiple layers include different absorbent materials, and multiple signal lines passing through the circuit board, wherein a first layer of the circuit board is composed of a first material that filters a first signal line traversing through at least the first layer of the multiple layers. An advantage of such a device is that the multiple layers may act as a low pass filter at frequencies where reactive components fail due to self-resonance.

[0004] In some embodiments of the above device, a second layer of the circuit board may include a second material that filters the first signal line traversing through at least the first and second layers of the plurality of layers. An advantage of such a device is that the absorptive materials of the plurality of layers may be selected based on the intended filtering of the first transmission line.

[0005] According to one embodiment, a system may include a device, the device including a circuit board including multiple layers, various of the multiple layers including one or more different absorbent materials, and multiple signal lines passing through the circuit board, wherein a first layer of the circuit board is composed of a first material and a second material, a first signal line traverses through at least the first layer, the first signal line including a first width traversing through the first material and a second width traversing through the second material. An advantage of such a system is that the first and second materials may act as a low pass filter for the signal lines.

[0006] In some embodiments of the above system, the system may further include a fabricated chip coupled to the first signal line. An advantage of such a system is that the fabricated chip allows for additional filtering and / or attenuation.

[0007] According to one embodiment, a method may include transmitting a signal and filtering the signal utilizing a filter circuit board, the filter circuit board having a plurality of layers, various of the plurality of layers including different absorptive materials, and a signal line traversing through at least a first layer of the plurality of layers, the signal line carrying the signal and the first layer being constructed from a first material that filters the signal line. An advantage of such a method is that the plurality of layers allows low-pass filtering at frequencies where reactive components fail due to self-resonance.

[0008] In some embodiments, the method may further include attenuating the signal using an attenuator coupled to the filter circuit board. An advantage of such a method is that it may improve signal coherence.

[0009] According to one embodiment, a system may include a device having a circuit board having a non-absorbing layer and multiple absorbing layers, where various ones of the multiple absorbing layers include different absorbing materials, and multiple signal lines passing through the circuit board, where a first layer of the circuit board is composed of a first material that filters a first signal line traversing through at least the first of the multiple absorbing layers. An advantage of such a device is that the multiple absorbing layers can act as a low pass filter at frequencies where reactive components fail due to self-resonance.

[0010] According to one embodiment, a method may comprise determining a desired frequency response of a filter, selecting one or more absorptive materials based on the desired frequency response, selecting traversal lengths of one or more signal lines for the one or more absorptive materials, and assembling a circuit board including a plurality of layers, wherein various ones of the plurality of layers include different absorptive materials of the one or more absorptive materials selected based on the desired frequency response. An advantage of such a method is that a filter may be designed to provide an intended filter response.

[0011] Various other details of the various embodiments described herein are provided in the following sections.

[0012] Item 1: A system comprising a device having a circuit board including multiple layers, various of the multiple layers including different absorbent materials; and multiple signal lines passing through the circuit board, a first layer of the circuit board composed of a first material configured to filter a first signal line traversing through at least the first of the multiple layers. An advantage of such a device is that the multiple layers can act as a low pass filter at frequencies where reactive components fail due to self-resonance.

[0013] Item 2: A system described in any preceding item specified in the Summary of the Invention, wherein a second layer of the circuit board is composed of a second material configured to filter the first signal line traversing through at least the first and second layers of the plurality of layers.

[0014] Item 3: The system of any preceding item specified in the Summary of the Invention, wherein the first signal line includes a first length traversing through the first layer and a second length traversing through the second layer.

[0015] Item 4: The system of any preceding item specified in the Summary of the Invention, further comprising one or more fabricated chips coupled to the circuit board.

[0016] Item 5: The system of any preceding item specified in the Summary of the Invention, wherein the one or more fabricated chips include at least one of an attenuator or a reactive low-pass filter.

[0017] Item 6: The system of any preceding item specified in the Summary of the Invention, wherein at least one layer of the plurality of layers includes at least one of an attenuator or a reactive low-pass filter.

[0018] Item 7: The system of any preceding item specified in the Summary of the Invention, wherein the first layer is formed of an absorbent material, the absorbent material configured to provide a low-pass filter function, and the second layer is formed of a second absorbent material, the second absorbent material configured to provide a second low-pass filter function.

[0019] Item 8: The system of any preceding item specified in the Summary of the Invention, wherein the first signal line is one of a microstrip or a stripline type.

[0020] Item 9: The system of any preceding item specified in the Summary of the Invention, further comprising a quantum computing system having the device.

[0021] Item 10: A system comprising a device having a circuit board including a plurality of layers, various of the plurality of layers including one or more different absorbent materials; and a plurality of signal lines passing through the circuit board, wherein a first layer of the circuit board is composed of a first material and a second material, a first signal line traversing at least through the first layer, the first signal line including a first width traversing through the first material and a second width traversing through the second material. An advantage of such a method is that a filter can be designed to provide an intended filter response.

[0022] Item 11: The system of any preceding item specified in the Summary of the Invention, further comprising a fabricated chip coupled to the first signal line.

[0023] Item 12: The system of any preceding item specified in the Summary of the Invention, wherein the fabricated chip comprises at least one of an attenuator or a reactive low-pass filter.

[0024] Item 13: The system of any preceding item specified in the Summary of the Invention, wherein the first signal line traverses through at least the first layer and the second layer.

[0025] Item 14: The system of any preceding item specified in the Summary of the Invention, wherein the second layer comprises at least one of an attenuator or a reactive low-pass filter.

[0026] Item 15: The system of any preceding item specified in the Summary of the Invention, further comprising a second fabricated chip coupled to a second signal line, the second signal line traversing through at least a third layer of the plurality of layers.

[0027] Item 16: The system of any preceding item specified in the Summary of the Invention, wherein the second fabricated chip comprises at least one of an attenuator or a reactive low-pass filter.

[0028] Item 17: A method comprising transmitting a signal; and filtering the signal utilizing a filter circuit board, wherein the filter circuit board includes: a plurality of layers, wherein various ones of the plurality of layers include different absorptive materials; and a signal line traversing through at least a first layer of the plurality of layers, wherein the signal line is configured to carry the signal, and wherein the first layer is composed of a first material configured to filter the signal line.

[0029] Item 18: A method as described in any preceding item specified in the Summary of the Invention, wherein the signal line traverses through at least the first and second layers of the plurality of layers, the second layer being composed of a second material configured to filter the signal line.

[0030] Item 19: The method of any preceding item specified in the Summary of the Invention, further comprising filtering the signal utilizing a reactive low-pass filter coupled to the filter circuit board.

[0031] Item 20: The method of any preceding item specified in the Summary of the Invention, further comprising attenuating the signal using an attenuator coupled to the filter circuit board.

[0032] Item 21: The method of any preceding item specified in the Summary of the Invention, wherein the signal comprises a control signal for a qubit in a quantum computer.

[0033] Item 22: The method of any preceding item specified in the Summary of the Invention, wherein the signal comprises a readout request signal for a qubit in a quantum computer.

[0034] Item 23: A system comprising a device having a circuit board including a non-absorbent layer and a plurality of absorbent layers, wherein various ones of the plurality of absorbent layers include different absorbent materials; and a plurality of signal lines passing through the circuit board, wherein a first layer of the circuit board is composed of a first material configured to filter a first signal line traversing through at least the first layer of the plurality of absorbent layers.

[0035] Item 24: The system of any preceding item specified in the Summary of the Invention, wherein a second signal line traverses through the non-absorbent layer.

[0036] Item 25: A method comprising: determining a desired frequency response of a filter; selecting one or more absorbing materials based on the desired frequency response; selecting traversal lengths of one or more signal lines for the one or more absorbing materials; and assembling a circuit board including a plurality of layers, wherein various ones of the plurality of layers include different absorbing materials of the one or more absorbing materials selected based on the desired frequency response. [Brief explanation of the drawings]

[0037] The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication containing color drawing(s) will be provided by the Office upon request and payment of the necessary fee.

[0038] [Figure 1] 1 illustrates a diagram of an exemplary, non-limiting filtering module in accordance with one or more embodiments described herein.

[0039] [Figure 2] 1 illustrates a cross-sectional view of an exemplary non-limiting filter module having high speed magnetic flux transmission lines according to one or more embodiments described herein.

[0040] [Figure 3]FIG. 1 illustrates a second cross-sectional view of an exemplary non-limiting filter module having radio frequency control lines according to one or more embodiments described herein.

[0041] [Figure 4] FIG. 10 illustrates a third cross-sectional view of an exemplary non-limiting filter module having readout lines according to one or more embodiments described herein.

[0042] [Figure 5] 1 shows a graph comparing the absorbency characteristics of various absorbent materials with filtering capabilities according to one or more embodiments described herein.

[0043] [Figure 6] 1 illustrates an algorithm for designing multiple absorbent layers according to one or more embodiments described herein.

[0044] [Figure 7A] 10 shows a graph illustrating filtering of one or more filter modules according to one or more embodiments described herein. [Figure 7B] 10 shows a graph illustrating filtering of one or more filter modules according to one or more embodiments described herein.

[0045] [Figure 8A] FIG. 1 illustrates a top view of a tapered signal line in a filter module according to one or more embodiments described herein.

[0046] [Figure 8B] 10A-10C illustrate alternative views of tapered signal lines in a filter module according to one or more embodiments described herein.

[0047] [Figure 9] 1 illustrates a diagram of a non-limiting filtering module according to one or more embodiments described herein.

[0048] [Figure 10] 10 shows a graph illustrating filtering of two filter modules according to one or more embodiments described herein.

[0049] [Figure 11] 1 illustrates a flow diagram of an exemplary, non-limiting method for designing a filter module according to one or more embodiments described herein.

[0050] [Figure 12] 1 shows a flow diagram of an exemplary non-limiting method for filtering an electromagnetic signal in accordance with one or more embodiments described herein.

[0051] [Figure 13] 1 shows a flow diagram of an exemplary non-limiting method for filtering an electromagnetic signal in accordance with one or more embodiments described herein.

[0052] [Figure 14] 1 illustrates a flow diagram of an exemplary, non-limiting method for designing a filter module according to one or more embodiments described herein. DETAILED DESCRIPTION OF THE INVENTION

[0053] The following detailed description is merely exemplary and is not intended to limit the embodiments and / or the application or uses of the embodiments, nor is it intended to be bound by any express or implied information presented in the preceding "Background" or "Summary" sections or in the "Detailed Description" section.

[0054] Quantum computing, in general, is the use of quantum mechanical phenomena to perform calculations and information processing functions. Quantum computing can be viewed in contrast to classical computing, which generally operates on binary values ​​using transistors. That is, while classical computers can operate on bit values ​​that are either 0 or 1, quantum computers operate on quantum bits (qubits) that contain superpositions of both 0 and 1, which can entangle multiple qubits and use interference. This quantum superposition allows quantum systems to store and represent large data sets that are difficult to represent classically. Quantum computing has the potential to solve problems that cannot be solved, or can only be solved slowly, in classical computers due to the complexity of the computations. In many forms of quantum computers, the qubits in the quantum computer are operated using radio frequencies. As such, a quantum computer can receive instructions from classical inputs and then execute the instructions using waveforms to operate the qubits in the quantum computer.

[0055] Scalable quantum computing architectures require high-density signal delivery of various types of waveform signals. For example, qubit and readout pulses at the input, fast flux pulses at the input, and readout pulses at the output have different and unique filtering and thermalization loss requirements to optimize qubit performance. Accordingly, filters for various types of signals require specific frequencies and roll-offs to minimize signal degradation, especially in baseband applications. Designing filters with desired roll-offs and cut-off frequencies is difficult with absorptive materials, which have their own characteristic roll-offs. Accordingly, the disclosed subject matter may utilize various techniques to realize modular architectures for passively filtering noise, attenuating noise, and thermalizing signals as they pass through temperatures.

[0056] Considering the problems described above with respect to filtering signals for the operation of a quantum computer, the present disclosure may be implemented to produce solutions to those problems in the form of devices, systems, apparatuses, and / or methods that may include a circuit board including multiple layers, where various of the multiple layers include different absorptive materials, and multiple signal lines passing through the circuit board, where a first layer of the circuit board is composed of a first material that filters a first signal line traversing through at least a first layer of the multiple layers. An advantage of such devices, systems, apparatuses, and / or methods is that the multiple layers may act as low-pass filters at frequencies where reactive components fail due to self-resonance. For example, each layer of the multiple absorptive layers through which the signal line traverses may contribute to filtering the signal line, thereby enabling desired filtering of the signal line.

[0057] One or more embodiments will now be described with reference to the drawings. Like reference numerals are used to refer to like elements throughout. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a more thorough understanding of one or more embodiments. It will be apparent, however, that in various instances one or more embodiments may be practiced without these specific details.

[0058] Furthermore, it will be understood that the embodiments illustrated in one or more of the figures described herein are for illustrative purposes only, and as such, the architecture of the embodiments is not limited to the systems, devices, and / or components illustrated therein, nor to any particular ordering, connection, and / or coupling of the systems, devices, and / or components illustrated therein.

[0059] Referring now to the drawings, FIG. 1 shows a diagram of an exemplary, non-limiting filter thermal loss module 100 according to one or more embodiments described herein.

[0060] As shown, the filter thermalized loss module 100 may include a connection 102 (e.g., from Ardent), a filter chip 104, an absorptive filter 140, and a second connection 106. In one embodiment, the connection 102 may provide a signal to the filter thermalized loss module 100. The signal may then pass through the filter chip 104. In one embodiment, the filter chip 104 may include a resonant filter 110, a passive filter 120, and an attenuator 130. In another embodiment, the filter chip 104 may additionally include a reactive low-pass filter. The signal may then pass from the filter chip 104 through the absorptive filter 140, and the second connection 106 may provide the filtered and attenuated signal from the substrate.

[0061] FIG. 2 illustrates a cross-sectional view of an exemplary, non-limiting filter module 200 having high-speed magnetic flux transmission lines (e.g., Z-control transmission lines) according to one or more embodiments described herein. As shown, filter module 200 may include first connection 201, second connection 202, chip shield 203, filtering chip 205, ball grid 206, interposer 207, bump bond 208, signal line 250, absorbing layer 240, absorbing layer 230, absorbing layer 220, absorbing layer 210, and non-absorbing layer 260. In one embodiment, absorbing layers 210-240 may include absorbing materials that filter out high-frequency radiation. In one embodiment, the absorbing materials may include materials such as blackbody absorbers. In one or more embodiments, the absorbing materials may be selected to provide different amounts of filtering and roll-off. Thus, different forms of absorbing materials may be selected depending on the filtering and roll-off needs. For example, layer 240 may include a first type of absorbent material, layer 230 may include a second type of absorbent material, layer 220 may include a third type of absorbent material, and layer 210 may include a fourth type of absorbent material. In one embodiment, absorbent materials that are irreversible (e.g., dissipate electrical energy) and / or magnetically loaded (e.g., are magnetically absorbent) may be utilized. In one embodiment, layers 210-240 may be layered by increasing absorption in descending layers. For example, layer 240 may be more absorbent than layer 230, which may be more absorbent than layer 220. In additional embodiments, layers 210-240 may be layered by decreasing absorption in descending layers. For example, layer 240 may be less absorbent than layer 230, which may be less absorbent than layer 220. In one embodiment, the absorbent material may include materials such as polyurethane foam, silicone rubber, carbon, or materials formed by a laminate manufacturing process. In one embodiment, the absorbent material may include one or more forms of Eccosorb®. In one embodiment, signal line 250 may traverse through one or more of layers 210-240 based on the filtering needs of signal line 250.For example, as shown, signal line 250 traverses horizontally through layers 240 and 230, but not through layers 210 or 220. Accordingly, signal line 250 is filtered by layers 240 and 230 and not filtered by layers 220 and 210. It should be understood that signal line 250 may traverse through different layers of different lengths. For example, as shown, signal line 250 traverses through layer 230 and a greater length through layer 240. As the length through which signal line 250 travels affects the filtering of signal line 250, different traversal lengths may be selected to achieve different amounts of filtering and roll-off. It should be understood that signal line 250 may include any form of microwave or radio frequency signal medium, such as, but not limited to, microstrip or stripline. It should also be understood that layers within the plurality of layers may include additional elements beyond absorbing materials. For example, one or more of the layers may include elements such as attenuators or reactive low pass filters.

[0062] FIG. 3 illustrates a second cross-sectional view of an exemplary, non-limiting filter module 200 having radio frequency control lines (e.g., XY control transmission lines) according to one or more embodiments described herein. Repeated descriptions of similar elements and / or processes utilized in each embodiment are omitted for brevity. In one embodiment, filter module 200 may include multiple signal lines. For example, as shown in FIG. 3, filter module 200 may include second signal line 350. As shown, second signal line 350 traverses horizontally through layer 220 but does not traverse horizontally through layers 210, 230, or 240. Accordingly, signal line 350 is filtered by layer 220 but not by layers 210, 230, or 240.

[0063] FIG. 4 illustrates a third cross-sectional view of an exemplary, non-limiting filter module 200 having a readout line according to one or more embodiments described herein. Repeated descriptions of similar elements and / or processes utilized in each embodiment are omitted for brevity. In one embodiment, the filter module 200 may additionally include a third signal line 450, which is a readout line intended to read out the state of one or more qubits in a quantum computer. Readout lines often do not utilize filtering, and the third signal line 450 does not pass through a filter chip or traverse through any of layers 210, 220, 230, or 240. Rather, the illustrated signal line 450 traverses through a non-absorbing layer 260, which does not provide any filtering for the third signal line 450. It should be understood that, in one embodiment, the filter thermalized loss module described herein may include any number of absorbing layers and / or any number of signal lines. In another embodiment, the signal line may traverse through any number of absorbing layers. For example, a fourth signal line (not shown) may traverse through layer 210, layer 220, layer 230, and layer 240, or any combination of layers. It should also be understood that a signal line may traverse through any layer for any distance or length.

[0064] In one embodiment, a variety of different forms and / or types of absorbent materials may be utilized. For example, different absorbent materials may have different properties, such as magnetic permeability (e.g., the change in magnetic field within a material), magnetic loss tangent (e.g., the amount of magnetic power lost in a material compared to the amount of magnetic power stored in the material), dielectric loss tangent (e.g., a measure of the dissipation of electrical energy passing through a material), attenuation per unit length (e.g., the amount of attenuation provided by a particular length of material), and other properties. Accordingly, different absorbent materials or absorbent material types may provide different filtering functions. In one embodiment, absorbent materials having a magnetic permeability in the range of 1.1 to 4.5 for 1 GHz signals may be utilized. In one embodiment, absorbent materials having a magnetic loss tangent in the range of 0 to 0.8 for 1 GHz signals may be utilized. In one embodiment, absorbent materials having a dielectric loss tangent in the range of 0.04 to 0.07 for 1 GHz signals may be utilized. In one embodiment, absorbent materials having an attenuation per unit length in the range of 0.09 to 27 dB per centimeter may be used. It should be understood that an absorptive material may have different properties depending on the frequency of a signal passed through it. For example, a material may have a different attenuation per unit length value for 1 GHz and 2 GHz signals. In one embodiment, a filter may include a first absorptive material having a magnetic permeability of 1.4 for 1 GHz signals, a magnetic loss tangent of 0.02 for 1 GHz signals, a dielectric loss tangent of 0.04 for 1 GHz signals, and an attenuation per unit length of 0.16 dB per centimeter. The filter may further include a second absorptive material having a magnetic permeability of 4.1 for 1 GHz signals, a magnetic loss tangent of 0.20 for 1 GHz signals, a dielectric loss tangent of 0.09 for 1 GHz signals, and an attenuation per unit length of 2.8 dB per centimeter.

[0065] 5 shows a graph 500 comparing the absorbency characteristics of various absorbent material types with Bessel-Thompson filters according to one or more embodiments described herein. Repetitive descriptions of similar elements and / or processes utilized in each embodiment are omitted for the sake of brevity.

[0066] The y-axis of graph 500 represents absorption (measured in dB) and the x-axis represents the frequency of the signal (measured in Hz). Accordingly, graph 500 shows absorption plotted as a function of frequency for a signal line traversing 1 cm through a variety of different absorbing materials. Line 510, shown as a solid blue line, represents a first absorbing material type, line 520, shown as a solid orange line, represents a second absorbing material type, line 530, shown as a solid green line, represents a third absorbing material type, and line 540, shown as a solid red line, represents a fourth absorbing material type. Line 525, shown as a dotted orange line, represents a Bessel-Thompson filter f -3dB = 2 GHz. The green dotted line 535 represents the Bessel-Thompson filter f -3dB = 1 GHz. The dotted red line 545 represents the Bessel-Thompson filter f -3dB = 200 MHz. As shown, a single type of absorbing material may, in some cases, not by itself provide the intended amount of filtering, as indicated by the difference between the solid and dotted lines. Accordingly, as described in more detail below, multiple types of absorbing material and / or different traversal lengths may be utilized to achieve the intended amount of filtering.

[0067] 6 illustrates an algorithm 600 for designing multiple absorbent layers according to one or more embodiments described herein. Repetitive descriptions of similar elements and / or processes utilized in each embodiment have been omitted for the sake of brevity.

[0068] As shown, 610 represents a column vector of a matrix showing absorption versus frequency data for various absorbing materials with different absorption characteristics, such as the types of absorbing materials shown in FIG. 5. For example, various absorbing materials may have different properties, such as different permeabilities, that provide different filter functions. 620 represents different lengths of traversal through the different absorbing materials represented in column 610. 630 is a column vector (e.g., absorption versus frequency) that represents the described filter transfer function of the signal line. Since the absorption at more frequency points is known than the type of absorbing material present, least-squares optimization can be used. For example, column 610 represents the variable

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[0069] 7A and 7B show graphs 700 and 750, respectively, illustrating filtering of one or more filter modules according to one or more embodiments described herein. Repetitive descriptions of similar elements and / or processes utilized in each embodiment are omitted for the sake of brevity.

[0070] The y-axis of graphs 700 and 750 represents absorption (measured in dB), and the x-axis represents the frequency of the signal (measured in Hz). Accordingly, graphs 700 and 750 show absorption plotted as a function of frequency for a signal line traversing through a filter module designed using least-squares optimization, as described above in connection with FIG. 7 . Line 710 of graph 700 represents the filter function of a fourth-order Bessel-Thompson filter with a cutoff of 1.9 GHz. This filter function can then be used as the described filter function for algorithm 600, as described above in reference to FIG. 7 . Line 720 of graph 700 represents the filter function of a filter designed using least-squares optimization, as described above in reference to FIG. 7 , where the filter function of line 710 is the described filter function. The filter function represented by line 720 includes a traversal distance of 2.13 cm for absorbing material type MF112 and 0.611 cm for MF117. As shown, line 720 closely approximates line 710 and illustrates the effectiveness of a filter module utilizing multiple absorbent layers and different distances traversed through the absorbent layers.

[0071] Line 770 of graph 750 represents the filter function of a fourth-order Bessel-Thompson filter with a 1 GHz cutoff. This filter function can then be used as the described filter function for algorithm 600, as described above with reference to FIG. 7. Line 770 of graph 750 represents the filter function of a filter designed using least-squares optimization, as described above with reference to FIG. 7, where the filter function of line 760 is the described filter function. The filter function represented by line 770 includes a traversal distance of 0.317 cm for absorbent material type MF124 and 0.6 cm for MF175. As shown, line 770 closely approximates line 760, demonstrating the effectiveness of a filter module utilizing multiple absorbent layers and different distances traversed through the absorbent layers.

[0072] FIG. 8A shows a top view 800 of a tapered signal line in a filter module 805 according to one or more embodiments described herein.

[0073] In one embodiment, multiple absorbent materials may be disposed adjacent to each other in a single layer, rather than multiple layers stacked on top of each other as shown in FIGS. 2-4 . For example, filter module 805 may include a first absorbent material 810 adjacent to a second absorbent material 820. A signal line 830 may traverse through the first absorbent material 810 and the second absorbent material 820. In one embodiment, the length of the first absorbent material 810 and the length of the second absorbent material 820 may be determined using least squares optimization, as described above with reference to FIG. 7 . In another embodiment, the width of the signal line 830 may vary between various absorbent materials. For example, as shown, signal line 830 includes a first width at point 832 in first absorbent material 810 and a second width at point 834 in second absorbent material 820. As shown, the first width is greater than the second width, but it should be understood that any difference in width and / or any number of variations in width between any number of absorbent materials is contemplated. In one embodiment, tapering the width of signal line 830 can improve the impedance match and return loss of signal 830, thereby improving the performance of a quantum computing system associated with filter module 805.

[0074] 8B shows an alternative view 815 of a tapered signal line in a filter module 805 according to one or more embodiments described herein. Repetitive descriptions of similar elements and / or processes utilized in each embodiment are omitted for the sake of brevity.

[0075] As described above with reference to FIG. 8A , in one embodiment, the absorbent materials are not stacked in layers, but rather, as described above with reference to FIGS. 2-4 , multiple absorbent materials may be disposed adjacent to each other in a single layer. For example, as shown by view 815, a first absorbent material 810 is disposed adjacent to a second absorbent material 820 in a single layer. In another embodiment, a layer of multiple layers may include one or more absorbent materials. For example, a layer of multiple layers may include a first absorbent material and a second absorbent material adjacent to each other.

[0076] 9 shows a diagram of a non-limiting filtering module 900 according to one or more embodiments described herein. Repetitive descriptions of similar elements and / or processes utilized in each embodiment are omitted for the sake of brevity.

[0077] Filter module 900 includes multiple absorptive layers (e.g., layers 910, 920, and 930) and a signal line 940 that traverses through layers 930 and 920. In one embodiment, as signal line 940 passes between different layers, vias may be used to connect between portions of signal line 940. For example, via 950 connects the portion of signal line 940 that traverses through layer 920 with the portion of signal line 940 that passes through layer 910. Similarly, via 960 connects the portion of signal line 940 that traverses through layer 930 with the portion of signal line 940 that traverses through layer 920. In one embodiment, different vias may be engineered for different portions of filter module 900 to provide impedance matching between layers. For example, via 950 may be engineered differently from via 960 based on the different properties of the layers to which it connects. In a further embodiment, the signal line 940 may include one or more microstrips having different shapes that, when combined, enable different filtering characteristics.

[0078] 10 shows a graph illustrating filtering of one or more filter modules according to one or more embodiments described herein. Repetitive descriptions of similar elements and / or processes utilized in each embodiment are omitted for the sake of brevity.

[0079] The y-axis of graph 1000 represents absorption (measured in dB), and the x-axis represents signal frequency (measured in Hz). Accordingly, graph 1000 shows absorption plotted as a function of frequency for a signal line traversing a filter module designed using least-squares optimization as described above in connection with FIG. 7, a filter module designed as described above in FIGS. 9A and 9B, and a filter module designed as described above in FIG. 10. Line 1030 of graph 1000 represents the filter function of a fourth-order Bessel-Thompson 1.9 GHz cutoff, which is used in this graph as a representation of the desired filter function. Line 1005 represents the filter function of a filter designed using least-squares optimization as described above in reference to FIG. 7. Line 1010 represents the filter function of a filter as designed as described above in FIGS. 9A and 9B. Line 1020 represents the filter function of a filter as designed as described above in FIG. 10. It should be appreciated that lines 1005, 1010, and 1020 all approximate line 1030, which demonstrates the effectiveness of one or more embodiments of the filter module described herein.

[0080] FIG. 11 illustrates a flow diagram of an exemplary, non-limiting method for designing a filter module according to one or more embodiments described herein.

[0081] At 1110, a desired frequency response (eg, vector b) for the filter may be provided.

[0082] At 1120, frequency dependent material properties can be obtained to arrive at an absorption per unit length for a particular transmission line shape to be used in the filter.

[0083] At 1130, a matrix (eg, A) may be assembled showing absorption per unit length versus frequency for different absorbing materials considered for use in the filter.

[0084] At 1140, the lengths of the different absorbent materials are represented by the vector

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[0085] A finite element simulation of a filter in which one of the absorbent layers has sections of different lengths can be performed at 1150. For example, a finite element simulation of a designed filter can be used to compare the filtering function of the designed filter with a desired filtering function.

[0086] 12 illustrates a flow diagram of an exemplary, non-limiting method 1200 for filtering an electromagnetic signal according to one or more embodiments described herein. Repetitive descriptions of similar elements and / or processes utilized in each embodiment are omitted for the sake of brevity.

[0087] At 1210, method 1200 may include transmitting signals. For example, as described above with reference to Figures 2 through 6, the signals may include various signals for operation of qubits in a quantum computer, such as high-speed magnetic flux transmissions and radio frequency control signals.

[0088] At 1220, method 1200 may include filtering the signal using a filter circuit board, wherein the filter circuit board has multiple layers, where various ones of the multiple layers include different absorptive materials, and a signal line traversing through at least a first layer of the multiple layers, where the signal line carries the signal and the first layer is composed of a first material that filters the signal line. For example, as described above with reference to Figures 2 through 4, the signal line may traverse through one or more absorptive layers, where each absorptive layer through which the signal line traverses contributes to filtering the signal carried by the signal line. Accordingly, the one or more absorptive layers through which the signal line traverses may achieve a desired filtering function that may not be possible with a single absorptive layer.

[0089] 13 shows a flow diagram of an exemplary, non-limiting method 1400 for filtering a signal according to one or more embodiments described herein. Repetitive descriptions of similar elements and / or processes utilized in each embodiment are omitted for the sake of brevity.

[0090] At 1310, method 1300 may include transmitting a signal. For example, as described above with reference to Figures 2 through 6, the signal may include various signals for operation of qubits in a quantum computer, such as high-speed magnetic flux transmissions and radio frequency control signals. In another embodiment, the electromagnetic signal may include any type of signal related to operation of a qubit or quantum hardware, such as a qubit control signal, a read request signal, and / or other operational signal.

[0091] At 1320, method 1300 may include filtering the signal using a filter circuit board, where the filter circuit board has multiple layers, where various ones of the multiple layers include different absorptive materials, and a signal line traversing through at least a first layer of the multiple layers, where the signal line carries the signal and the first layer is composed of a first material that filters the signal line. For example, as described above with reference to Figures 2 through 4, the signal line may traverse through one or more absorptive layers, where each absorptive layer through which the signal line traverses contributes to filtering the signal carried by the signal line. Accordingly, the one or more absorptive layers through which the signal line traverses may achieve a desired filtering function that may not be possible with a single absorptive layer.

[0092] At 1330, the method 1300 may include filtering the signal utilizing a reactive low pass filter coupled to a filter circuit board. For example, as described above with reference to Figures 2-4, a fabricated chip including a reactive low pass filter may be coupled to the circuit board. In another example, the circuit board may include a reactive low pass filter between multiple layers.

[0093] At 1340, the method 1300 may include attenuating the signal using an attenuator coupled to the filter substrate. For example, a fabricated chip including the attenuator may be coupled to a circuit board, as described above with reference to Figures 2-4. In another example, the circuit board may include the attenuator between multiple layers.

[0094] At 1350, method 1300 may include receiving a second signal, where the second signal includes a readout of the state of a qubit in the quantum computer. For example, as described above with reference to Figures 2-4, the readout signal does not require filtering, and therefore, the signal line carrying the readout signal may traverse through a non-absorbing layer of the filter circuit board to prevent filtering of the readout signal.

[0095] FIG. 14 illustrates a flow diagram of an exemplary, non-limiting method 1400 for designing a filter module according to one or more embodiments described herein.

[0096] At 1410, the method 1400 may include determining a desired frequency response. For example, the desired frequency response may be identified or provided based on the type of signal line.

[0097] At 1420, method 1400 may include selecting one or more absorbent materials based on the desired frequency response. For example, as described in detail above, a least squares optimization method may be utilized to select one or more different absorbent materials to achieve the desired frequency response.

[0098] At 1430, method 1400 may include selecting a traversal length of one or more signal lines through one or more absorbent materials. For example, as described above, a least squares optimization method may be used to select the traversal length of the signal lines through the one or more absorbent materials based on a desired frequency response.

[0099] At 1440, the method 1400 may include assembling a circuit board including a plurality of layers, where various ones of the plurality of layers include different absorbent materials of one or more absorbent materials selected based on a desired frequency response.

[0100] An advantage of such methods, systems, and / or devices is that filter modules produced by such methods, systems, and / or devices enable specific filtering functions at low frequencies where reactive components fail due to self-resonance. For example, filters in quantum computers require specific cutoff frequencies and rolloffs to minimize signal degradation. Therefore, filter modules such as those described above may enable the desired filtering function by having signal lines traverse through one or more absorptive layers, where each layer the signal line traverses contributes to filtering. Furthermore, different filtering functions may be achieved by varying the traversal distance of the signal line through the absorptive layers. By utilizing least-squares optimization, as described above, to select different absorptive layers and signal lines traversing through different absorptive layers, a desired filtering function that produces a desired cutoff frequency and rolloff may be achieved. By achieving this desired filtering function, the filter modules described herein may reduce signal degradation, thereby improving the performance of the quantum computer by reducing degradation of microwave or radio frequency signals used to manipulate qubits within the quantum computer.

[0101] In view of one or more embodiments described herein, a practical application of the devices described herein is reduced signal degradation in quantum computing systems, which facilitates improved quantum computing system performance and, therefore, improvements in quantum system process capability, speed, and / or accuracy.

[0102] Furthermore, one or more embodiments described herein may be utilized in real-world systems based on the disclosed teachings. For example, one or more embodiments described herein may function within a system that may receive input as a quantum job request and generate as real-world physical pulses to be operated on one or more qubits of a quantum system. Output signals of one or more physical qubit devices and / or pulses operated on one or more qubits may be filtered by a device according to one or more embodiments described herein. Each quantum system may produce one or more quantum results depending on the performance of one or more physical operations on the real-world qubits of the quantum system.

[0103] It should also be understood that one or more embodiments described herein may utilize hardware to solve problems that are highly technical, non-abstract, and cannot be performed as a set of mental activities by a human. For example, a human, or thousands of humans, cannot efficiently, accurately, and / or effectively filter signals from a quantum computer.

[0104] One or more embodiments described herein may be fully operational toward performing one or more other functions (e.g., fully powered on, fully running, and / or another function) while also performing one or more operations described herein. It should be understood that such simultaneous multiple operation performance is beyond the capabilities of the human mind.

Claims

1. a circuit board comprising a plurality of layers, wherein various ones of the plurality of layers comprise different absorbent materials; and a plurality of signal lines passing through the circuit board, wherein a first layer of the circuit board is comprised of a first material configured to filter first signal lines traversing through at least the first layer of the plurality of layers; A device having A system comprising:

2. 10. The system of claim 1, wherein a second layer of the circuit board is comprised of a second material configured to filter the first signal line traversing through at least the first layer and the second layer of the plurality of layers.

3. 3. The system of claim 2, wherein the first signal line includes a first length that traverses through the first layer and a second length that traverses through the second layer.

4. 10. The system of any preceding claim, further comprising one or more fabricated chips coupled to the circuit board.

5. The system of claim 4 , wherein the one or more fabricated chips comprise at least one of an attenuator or a reactive low pass filter.

6. 10. The system of any preceding claim, wherein at least one layer of the plurality of layers comprises at least one of an attenuator or a reactive low pass filter.

7. 3. The system of claim 2, wherein the first layer is formed of an absorbent material, the absorbent material configured to provide a low pass filter function, and the second layer is formed of a second absorbent material, the second absorbent material configured to provide a second low pass filter function.

8. 10. A system according to any preceding claim, wherein the first signal line is of one of the following types: microstrip or stripline.

9. 10. The system of any preceding claim, wherein one or more of the layers comprises a non-absorbent material.

10. a circuit board comprising a plurality of layers, wherein various ones of the plurality of layers comprise one or more different absorbent materials; and a plurality of signal lines passing through the circuit board, wherein a first layer of the circuit board is composed of a first material and a second material, a first signal line traversing through at least the first layer, the first signal line including a first width traversing through the first material and a second width traversing through the second material; A device having A system comprising:

11. The system of claim 10 further comprising a fabricated chip coupled to the first signal line.

12. The system of claim 11 , wherein the fabricated chip comprises at least one of an attenuator or a reactive low pass filter.

13. 13. A system according to any preceding claim 10 to 12, wherein the first signal line traverses through at least the first and second layers.

14. The system of claim 13 , wherein the second layer comprises at least one of an attenuator or a reactive low pass filter.

15. 15. The system of any of the preceding claims 10 to 14, further comprising a second fabricated chip coupled to a second signal line, the second signal line traversing through at least a third layer of the plurality of layers.

16. 16. The system of claim 15, wherein the second fabricated chip comprises at least one of an attenuator or a reactive low pass filter.

17. transmitting a signal; and filtering the signal using a filter circuit board; wherein the filter circuit board comprises: a plurality of layers, wherein various ones of the plurality of layers comprise different absorbent materials; and a signal line traversing through at least a first layer of the plurality of layers, the signal line configured to carry the signal, the first layer being comprised of a first material configured to filter the signal line; A method comprising:

18. 20. The method of claim 17, wherein the signal line traverses through at least the first and second layers of the plurality of layers, the second layer being comprised of a second material configured to filter the signal line.

19. 19. The method of any of the previous claims 17-18, further comprising filtering the signal utilizing a reactive low pass filter coupled to the filter circuit board.

20. 20. The method of any of the preceding claims 17 to 19, further comprising attenuating the signal using an attenuator coupled to the filter circuit board.

21. 21. A method according to any preceding claim 17 to 20, wherein the signal comprises a control signal for a qubit in a quantum computer.

22. 22. The method of any of the preceding claims 17 to 21, wherein the signal comprises a readout request signal for a qubit in a quantum computer.

23. a circuit board comprising a non-absorbent layer and a plurality of absorbent layers, wherein various ones of the plurality of absorbent layers comprise different absorbent materials; and a plurality of signal lines passing through the circuit board, wherein a first layer of the circuit board is comprised of a first material configured to filter first signal lines traversing through at least the first layer of the plurality of absorbent layers; A device having A system comprising:

24. 24. The system of claim 23, wherein a second signal line traverses through the non-absorbing layer.

25. determining a desired frequency response of the filter; selecting one or more absorbent materials based on the desired frequency response; selecting a traversal length of one or more signal lines for the one or more absorbent materials; and Assembling a circuit board including a plurality of layers, wherein various ones of the plurality of layers include different absorbent materials of the one or more absorbent materials selected based on the desired frequency response. A method comprising:

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