System and method for supporting a high thermal gradient between a qubit surface and a qubit surface control system using a superconducting rigid-flex circuit.
The superconducting rigid-flex circuit with independent cooling systems addresses the thermal gradient challenge in quantum devices, enabling efficient heat dissipation and high-density interconnects for scalable quantum computing.
Patent Information
- Application Number
- JP2026501130
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-08-14
- Filing Date
- 2024-07-10
- Publication Date
- 2026-08-26
AI Technical Summary
Controlling quantum devices at cryogenic temperatures is challenging due to the bottleneck of input/output density and heat dissipation by associated control circuits, as conventional cooling systems like dilution refrigerators do not support high thermal gradients needed for scalable quantum computing.
A superconducting rigid-flex circuit is used to interconnect qubit and control chips, with independent cooling systems maintaining different temperature zones, allowing for thermal isolation and high-density interconnects without requiring connectors, and enabling efficient heat dissipation from both chips.
This approach supports high thermal gradients and high-density interconnects over long distances, maintaining qubit and control chip temperatures within cryogenic limits, thereby preventing overheating and minimizing noise-induced diffusion.
Smart Images
Figure 2026528881000001_ABST
Abstract
Description
[Background technology]
[0001]
[0001] Controlling quantum devices requires generating large amounts of static and dynamic voltage signals, and for quantum devices operating at cryogenic temperatures, it would be ideal to generate these signals at a cryogenic temperature closely integrated with the quantum device. This presents a significant challenge, given that cryogenic environments severely restrict the power consumption of any active electronic device. In addition, it is necessary to couple large amounts of voltage signals to the electrodes of the quantum device's qubit gates. As a result, it may sometimes be necessary to connect thousands or even millions of wires to voltage or current sources to drive the qubit gates of a quantum device. [Overview of the project] [Problems that the invention aims to solve]
[0002]
[0002] In short, controlling a large number of qubits is a major challenge due to the bottleneck of input / output density and heat dissipation by associated control circuits. Control chips operating near the qubits help address this challenge, but the qubit chips must be cooled to millikelvin temperatures where cooling is severely limited. In contrast, the electronics required to control qubit devices are housed in integrated circuit chips that consume tens of microwatts to milliwatts of power. These integrated circuit chips generate heat commensurate with this much higher amount of power consumption, which must be removed to prevent the qubit surface from exceeding its cryogenic operating temperature (e.g., 100 mK). Therefore, better systems and methods are needed to support the high thermal gradient between the qubit surface and the qubit surface control system. [Means for solving the problem]
[0003]
[0003] In one example, the present disclosure relates to a system comprising a qubit surface having at least one qubit chip associated with a first rigid circuit portion of a superconducting rigid-flex circuit. The system may further include a first cooling system capable of operating the qubit surface and the first rigid circuit portion of the superconducting rigid-flex circuit at 100 millikelvin or less.
[0004]
[0004] The system may further include a control system having at least one control chip associated with a second rigid circuit portion of the superconducting rigid-flex circuit. The system may further include a second cooling system capable of operating to maintain the operating temperature of the control system and the second rigid circuit portion of the superconducting rigid-flex circuit below 10 Kelvin, so that at least one control chip can dissipate heat to the second cooling system within a thermal budget commensurate with the amount of power required to supply control signals and control qubits in at least one qubit chip. The system may further include a flexible circuit portion of the superconducting rigid-flex circuit for interconnecting a first rigid circuit portion of the superconducting rigid-flex circuit with a second rigid circuit portion of the superconducting rigid-flex circuit.
[0005]
[0005] In another example, the present disclosure relates to a method comprising providing a qubit surface having at least one qubit chip associated with a first rigid circuit portion of a superconducting rigid-flex circuit. The method may further include using a first cooling system that maintains the operating temperature of the qubit surface and the first rigid circuit portion of the superconducting rigid-flex circuit below 100 millikelvin.
[0006]
[0006] The method may further include providing a control system having at least one control chip associated with a second rigid circuit portion of the superconducting rigid-flex circuit. The method may further include using a second cooling system that maintains the operating temperature of the control system and the second rigid circuit portion of the superconducting rigid-flex circuit below 10 Kelvin, so that the control chip can dissipate heat to the second cooling system within a thermal budget commensurate with the amount of power required to supply control signals and control qubits in at least one qubit chip. The method may further include providing a flexible circuit portion of the superconducting rigid-flex circuit for interconnecting a first rigid circuit portion of the superconducting rigid-flex circuit with a second rigid circuit portion of the superconducting rigid-flex circuit.
[0007]
[0007] In yet another example, the present disclosure relates to a system configured to operate in a cryogenic environment, wherein the cryogenic environment is 10 -3 From Toru 10 -10 The system has a vacuum with a pressure in the range of Torr. The system may further include a qubit surface having a qubit chip associated with a first rigid circuit portion of a superconducting rigid-flex circuit. The system may further include a first cooling system capable of operating to maintain the operating temperature of the qubit surface and the first rigid circuit portion of the superconducting rigid-flex circuit below 100 millikelvin.
[0008]
[0008] The system may further include a control system having a control chip associated with a second rigid circuit portion of the superconducting rigid-flex circuit. The system may further include a second cooling system capable of operating to maintain the operating temperature of the control system and the second rigid circuit portion of the superconducting rigid-flex circuit below 10 Kelvin, so that the control chip can dissipate heat to the second cooling system within a thermal budget commensurate with the amount of power required to supply control signals and control the qubits in the qubit chip.
[0009]
[0009] The system may further include a flexible circuit portion of the superconducting rigid-flex circuit for interconnecting a first rigid circuit portion of the superconducting rigid-flex circuit with a second rigid circuit portion of the superconducting rigid-flex circuit, but for thermal insulation. The system may further include a third cooling system that can operate to maintain the operating temperature of the flexible circuit portion within the range of 100 millikelvin to 10 Kelvin.
[0010]
[0010] This summary is provided to introduce a selection of concepts in a simplified form, which will be further described in the following detailed description. This summary is not intended to identify any major or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
[0011] Brief explanation of the drawing
[0011] This disclosure is illustrated as an example and is not limited to the accompanying drawings in which similar reference numerals indicate similar elements. The elements in the figures are illustrated for brevity and clarity and are not necessarily drawn to a uniform scale. [Brief explanation of the drawing]
[0012] [Figure 1]
[0012] An example of a system for supporting a high thermal gradient between the qubit surface and the qubit surface control system is shown using a superconducting rigid-flex circuit. [Figure 2]
[0013] The thermal resistance model of the system in Figure 1 is shown. [Figure 3]
[0014] Another example of a system using a superconducting rigid-flex circuit to support a high thermal gradient between the qubit surface and the qubit surface control system is presented. [Figure 4]
[0015] The thermal resistance model of the system shown in Figure 3 is presented. [Figure 5]
[0016] A side view of a superconducting rigid-flex circuit for use with the systems shown in Figures 1 and 2 is shown. [Figure 6]
[0017] This figure shows a side view of the rigid circuit portion of a superconducting rigid-flex circuit for use with the systems shown in Figures 1 and 2. [Modes for carrying out the invention]
[0013] Detailed explanation
[0018] This disclosure relates to a system and method for supporting a high thermal gradient between a qubit surface and a qubit surface control system using a superconducting rigid-flex circuit. To facilitate scalable and large-scale quantum computing, the cryogenic control system of a quantum device must remain thermally isolated while being interconnected with thousands of wires within the system. This is a major challenge, as current thermal cooling designs that achieve millikelvin (mK) temperatures (e.g., dilution refrigerators) do not support this performance. Dilution refrigerators are capable of cooling heat in the microwatt range to tens of mK (by He3 / He4 mixtures). The electronics required to control the qubit device are housed in integrated circuit chips that consume tens of microwatts to several milliwatts of power. These integrated circuit chips generate heat commensurate with this much higher amount of power consumption, which must be removed to prevent the qubit surface from exceeding its cryogenic operating temperature (e.g., 100 mK).
[0014]
[0019] Certain dilution refrigerators can provide higher cooling power at higher temperatures in various stages within the refrigerator. One such zone in a dilution refrigerator, known as a cryogenic plate, is a potential candidate for housing cryogenic control electronics on a qubit surface. The cryogenic plate zone can operate at approximately 100–600 mK. However, the sub-100 mK temperature zone within the dilution refrigerator is separated from the cryogenic plate zone and lies on a different plane, making it difficult to have a single planar printed circuit board that can be thermally mounted to both temperature zones.
[0015]
[0020] Examples of the present disclosure relate to using a superconducting rigid flex circuit as an interconnection between a cryogenic control system for a qubit chip and the qubit chip itself. With this approach, assuming that the thermal conductivity of a superconductor is much lower than that of a normal conductor, while being connected to a qubit plane that must operate at less than 100 mK and generate only a few microwatts of heat, the cryogenic control system can operate at a much higher temperature than the qubit chip and generate heat from several tens of microwatts to several milliwatts. In short, this approach enables electrical conductivity between the control chip and the qubit chip while thermally insulating within a dilution refrigerator or using multiple dilution refrigerators.
[0016]
[0021] FIG. 1 shows an exemplary system 100 for supporting a high thermal gradient between a qubit plane and a qubit plane control system using a superconducting rigid flex circuit. System 100 is configured to operate in a cryogenic environment. A system operating in a cryogenic environment requires a vacuum to operate properly. In one example, the vacuum may be related to pressures in the range of 10 -3 torr to 10 -10 torr. In one example, the temperature range of the cryogenic environment can be between 5 millikelvin and 10 kelvin. It should be recognized that the temperature ranges referred to herein relate to the temperature of the environment in which the components of system 100 are operating and not to the temperature of the components themselves. Thus, when referring to "operating at" or "maintained at," etc., these refer to the temperature of the environment in which these components are operating or being maintained internally.
[0017]
[0022] Continuing to refer to FIG. 1, the system 100 can include two different temperature zones, namely, one temperature zone of 10K or less and another temperature zone of 100mK or less. The temperature zone of 10K or less includes components related to the qubit plane control system 110, and the temperature zone of 100mK or less includes components related to the qubit plane 170. In this example, the system 100 includes a superconducting rigid-flex circuit, which is implemented as a rigid-flex printed circuit board (PCB). The superconducting rigid-flex circuit includes a rigid circuit portion 130, a flexible circuit portion 150, and another rigid circuit portion 180. In this example, the rigid circuit portion 130 and the rigid circuit portion 180 can each include both a superconducting interconnect layer and a non-superconducting interconnect layer. However, the flexible circuit portion 130 includes only the superconducting interconnect layer. The control chips (e.g., integrated circuit chips) 112, 114, and 116 are associated with the control system 110, but they are mounted (or otherwise coupled) to the rigid circuit portion 130.
[0018]
[0023] One type of control architecture for controlling a qubit (e.g., a solid-state qubit) includes one or more integrated circuit control chips containing cryogenic control circuits. Each control chip can generate a voltage bias by accumulating charge in capacitors (including interconnect capacitance). One or more digital-to-analog converters can be used to set the charge in each capacitor, which remains for a long time at these temperatures because the leakage path is extremely low at cryogenic temperatures. Charge refresh can be performed periodically on a timescale commensurate with the operation of the qubit. As an example, the control system may include an analog-to-digital converter (ADC), a digital-to-analog converter (DAC), a digital signal processor (DSP), and a field-programmable gate array (FPGA). The control chip associated with the qubit control system 110 can be implemented using a variety of semiconductor technologies, including complementary metal-oxide-semiconductor (CMOS), silicon-germanium (SiGe) semiconductors, or III-V compound semiconductors. The control chip may further include passive circuits, voltage dividers, capacitors, resistors, interconnect structures, and other circuits / structures.
[0019]
[0024] Referring again to Figure 1, the qubit chips 172, 174, and 176 are associated with the qubit surface 170, which is mounted (or otherwise coupled) to the rigid circuit portion 180. The qubit surface 170 may contain topological qubits (qubits) or other solid-state qubits that may be required to operate at temperatures below 100 millikelvin (e.g., in the range of approximately 5 millikelvin to 100 millikelvin). Qubits can process quantum information for quantum computers. Qubits can be implemented using a variety of physical systems, including photons, electrons, Josephson junctions, quantum dots, or heterostructures. Quantum states may be encoded as the direction of spin, another aspect of spin, charge, energy, or excitation stage as part of the qubit, or as the topological phase of a superconducting material. This exemplary qubit can operate based on either a low-frequency DC signal (e.g., bias voltage or current) or a high-frequency radio frequency signal (e.g., a signal from 1 GHz to 10 GHz), or a combination of both. In certain cases, microwave signals can be used to control superconducting devices, including the state of qubits. Certain implementations of qubit gates may require high-frequency microwave signals. Qubits can be read out using frequency multiplexing.
[0020]
[0025] Dynamic control of qubits may require one or more voltage pulses to rapidly change the gate potential and the energy state of the qubits. Generating such pulses remotely from the qubit surface requires considerable energy, as attenuators are often used at each temperature stage for thermal neutronization of electrons. Signals (e.g., pulses or other signals) for controlling each qubit may include left wall (LW) signals, left plunger (LP) signals, center wall (CW) signals, right plunger (RP) signals, and right wall (RW) signals. Additional signals related to sensing quantum dots within the qubit gates may include dot top gate sensing signals, dot plunger sensing signals, and dot bottom gate sensing signals. Depending on the type of qubit, additional or different control signals may be required. Since each qubit chip associated with the qubit surface 170 contains thousands of qubits, the electronics required to control the qubit chips in the control system 110 consume milliwatts of power when generating such qubit control signals. Therefore, the control chip associated with the control system 110 generates heat commensurate with this much higher amount of power consumption, which must be eliminated in order to prevent the qubit surface from exceeding its cryogenic operating temperature (e.g., 100 mK).
[0021]
[0026] Continuing to refer to Figure 1, the flexible circuit portion 150 of the superconducting rigid-flex circuit includes interconnecting superconducting wiring and other such structures to enable interconnection between the control chips 112, 114, and 116 and the qubit chips 172, 174, and 176. The flexible circuit portion 150 can be formed as a flexible circuit by forming superconducting metal wiring (e.g., KAPTON®) such as polyimide on a flexible substrate. The superconducting metal can be any superconducting metal including niobium or aluminum. Other relevant alloys (e.g., niobium nitride (NbN) or titanium niobium nitride (NbTiN)) may also be used. Multiple layers of superconducting metal separated by a flexible dielectric (e.g., polyimide) may be formed as part of the flexible circuit portion 150. The superconducting metal layers may also be laminates of superconductors (e.g., niobium or niobium nitride). The superconducting metal layer associated with the flexible circuit portion 150 is formed to extend into the rigid circuit portions 130 and 180. Additional details regarding the formation of the superconducting rigid-flex circuit are provided with reference to Figures 5 and 6.
[0022]
[0027] Referring again to Figure 1, as part of system 100, two cooling systems are used: one for the qubits and a second for the control system that controls the qubits. As described herein, the two cooling systems may be completely independent cooling systems or they may be subsystems of the same cooling system (e.g., a single dilution refrigerator). Cooling system 120 coupled to the rigid circuit portion 130 and the qubit (e.g., devices 112, 114, and 116) control system 110 is configured to achieve the temperature range of the cryogenic control system (e.g., less than 10K). As mentioned above, in one example, cooling system 120 may correspond to a cryogenic plate or another type of cooling system (e.g., a liquid helium pipe or other such cooling system). Cooling system 160 coupled to the rigid circuit portion 170 and the qubit surface 170 having an integrated circuit chip containing the qubits (e.g., qubit devices 172, 174, and 176) is configured to achieve the temperature range of the qubit surface (e.g., less than 100mK). The cooling system 160 may include a dilution refrigerator, a pump-operated helium-3 refrigerator, or a pump-operated helium-4 refrigerator. The dilution refrigerator can be configured by setting various parameters of the heat exchanger, including the configuration of the mixing chamber, the flow impedance, the ratio of 3He to 4He, and the flow rate of the mixture.
[0023]
[0028] An advantage is that physically separating the qubits from the qubit control system using superconducting rigid-flex circuits eliminates the need for these subsystems to coexist on the same geometric plane, while simultaneously providing thermal isolation. In addition, heat is extracted from both the control chip and the qubit chip in a direction orthogonal to the plane on which these chips are located. Furthermore, an advantage is that using superconducting rigid-flex circuits enables PCB-level wiring density without the need for connectors to connect the control chip of the control system and the qubit chip on the qubit plane, respectively.
[0024]
[0029] The two cooling systems can be part of a single dilution refrigerator, provided that the heat leakage from the cryogenic plate to the mixing chamber plate is within the specifications of the mixing chamber. If the heat leakage is too large, the control system can be cooled using any stage of the dilution refrigerator (or alternative cooling system), or different dilution refrigerators can be used as the qubit surface cooling system. Furthermore, as will be discussed later with respect to Figure 4, the flexible circuit portion 150 can be thermally neutronized using a different cooling state or a different dilution refrigerator when it is routed from the control system to the qubit surface. Advantageously, the system 100 as described with respect to Figure 1, and the method for operating this system, support high-density interconnects over relatively long distances and high thermal gradients (e.g., 10K to 100mK). High thermal gradients between high-temperature and low-temperature areas are possible without requiring special substrates such as Macor. As will be discussed later, this method also provides an additional opportunity to thermally neutronize the wiring as it passes from the high-temperature to the low-temperature area. As a result, system 100 provides a means of using a single cold finger with a more uniform magnetic field compared to having multiple cold fingers, which would require larger magnets and apertures and complicate the positioning of the quantum device.
[0025]
[0030] Furthermore, as part of system 100, the qubits can be read by coupling them to a resonator such that the resonant frequencies are shifted differently depending on the two different states of the qubits. For example, the frequency shift can be detected by measuring the phase of a microwave pulse using the resonator. An increase in electron temperature caused by the injection of high-temperature electrons from the control system 110 into the qubit surface 170 can cause noise-induced diffusion of the resonant function. The isolation between the control system 110 and the qubit surface 170 provided by the flexible circuit portion 150 also helps prevent such noise-related problems by minimizing the effect of high-temperature electrons on the performance of the qubits in the qubit surface 170. Figure 1 shows that system 100 includes certain components arranged in a particular way, but system 100 may include additional components with different arrangements or fewer components. For example, the control chip may be coupled to the rigid circuit portion 130 in a different coupling type than shown in Figure 1. Similarly, the qubit chip may be coupled to the rigid circuit portion 180 in a different coupling type than shown in Figure 1.
[0026]
[0031] Figure 2 shows the thermal resistance model 200 of system 100 in Figure 1. Each resistor (R) in this thermal resistance model FLEXIBLE CIRCUIT , R CONTROL , and R QUBIT ) represents a certain amount of thermal resistance, and the current flowing through the resistor can be considered as the amount of heat flowing through the resistor. The thermal resistance model 200 further includes a first cooling system node 230 and another cooling system node 240. In this model, the node labeled control system node 210 corresponds to the temperature of the rigid circuit portion (e.g., rigid circuit portion 110 in Figure 1) and the control circuits for controlling the qubit, and the other node labeled qubit node 220 corresponds to the temperature of another rigid circuit portion (e.g., rigid circuit portion 170 in Figure 1) and the qubit surface.
[0027]
[0032] By using the thermal resistance model 200 to calculate heat transfer across regions, the performance of the system 100 in FIG. 1 can be evaluated and enhanced. Despite a large temperature gradient between the control system node 210 and the qubit node 220, most of the heat dissipated by the control system node 210 flows to the cooling system node 230. This approach is facilitated by using an anisotropic thermally conductive substrate where heat transport is in the vertical rather than the horizontal direction for cooled devices. This enables easy removal of independent heat from these two while minimizing the heat flow between the control system node 210 and the qubit node 220. In short, the PCB layers in the rigid-flex circuit are intentionally designed to mimic thermal anisotropy. Although not shown in FIG. 2, it may also be advisable to perform thermal resistance modeling of additional temperature stages and cooling systems associated with the rigid circuit portion (e.g., the rigid circuit portion 110 in FIG. 1) and the control circuits for controlling qubits, and another rigid circuit portion (e.g., the rigid circuit portion 170 in FIG. 1) and the qubit plane.
[0028]
[0033] FIG. 3 shows another exemplary system 300 for supporting a high thermal gradient between a qubit plane and a qubit plane control system using a superconducting rigid-flex circuit. The same or similar components shown in FIG. 3 are referenced using the same reference numbers as those used in FIG. 1. The system 300 (similar to the system 100) is also configured to operate in a cryogenic environment that includes a vacuum having a pressure in the range of 10 -3 Torr to 10 -10 Torr. In one example, the cryogenic environment may need to have a temperature range between 5 millikelvin and 10 kelvin.
[0029]
[0034] Continuing to refer to Figure 3, as in system 100, system 300 can include two different temperature zones, namely one below 10K and the other below 100mK. The below 10K temperature zone includes components related to the qubit plane control system 110, and the below 100mK temperature zone includes components related to the qubit plane 170. System 300 includes a superconducting rigid-flex circuit, which is implemented as a rigid-flex printed circuit board (PCB). The superconducting rigid-flex circuit includes a rigid circuit portion 130, a flexible circuit portion 150, and another rigid circuit portion 180. In this example, the rigid circuit portion 130 and the rigid circuit portion 180 can each include both a superconducting interconnect layer and a non-superconducting interconnect layer. However, the flexible circuit portion 130 includes only a superconducting interconnect layer. The control chips (e.g., integrated circuit chips) 112, 114, and 116 are associated with the control system 110, but they are mounted (or otherwise coupled) to the rigid circuit portion 130. A similar type of control architecture for controlling qubits (e.g., solid-state qubits), such as one or more integrated circuit control chips including cryogenic control circuits, can be used with the system 300.
[0030]
[0035] Referring again to Figure 3, similar to system 100 in Figure 1, the qubit chips 172, 174, and 176 are associated with the qubit surface 170, but they are mounted (or otherwise coupled) to the rigid circuit portion 180. The qubit surface 170 may contain topological qubits (qubits) or other solid-state qubits that may be required to operate at temperatures below 100 millikelvin (e.g., in the range of approximately 5 millikelvin to 100 millikelvin). As mentioned above, since each qubit chip associated with the qubit surface 170 has thousands of qubits, the electronics required to control the qubit chips in the control system 110 consume milliwatts of power when generating such control signals for the qubits. For this reason, the control chip associated with the control system 110 generates heat commensurate with this much higher amount of power consumption, which must be removed to prevent the qubit surface from exceeding its cryogenic operating temperature (e.g., 100 mK).
[0031]
[0036] Continuing to refer to Figure 3, as in system 100 of Figure 1, the flexible circuit portion 150 includes interconnection wiring and other such structures to enable interconnection between control chips 112, 114, and 116 and qubit chips 172, 174, and 176. The flexible circuit portion 150 can be formed as a flexible circuit by forming superconducting metal wiring (e.g., KAPTON®) such as polyimide on a flexible substrate. The superconducting metal can be any superconducting metal including niobium or aluminum. Other relevant alloys (e.g., niobium nitride (NbN) or titanium niobium nitride (NbTiN)) may also be used. Multiple layers of superconducting metal separated by a flexible dielectric (e.g., polyimide) may be formed as part of the flexible circuit portion 150. The superconducting metal layers may also be laminates of superconductors (e.g., niobium or niobium nitride). The superconducting metal layer associated with the flexible circuit portion 150 is formed to extend into the rigid circuit portions 130 and 180. Additional details regarding the formation of the superconducting rigid-flex circuit are provided with reference to Figure 5.
[0032]
[0037] Referring again to Figure 3, unlike system 100 in Figure 1, system 300 uses three cooling systems as part of the system: one for the qubits, a second for the flexible circuit portion, and a third for the control system for controlling the qubits. As described herein, the three cooling systems may be completely independent cooling systems or they may be subsystems of the same cooling system (e.g., a single dilution refrigerator). Cooling system 120 coupled to the rigid circuit portion 130 and the qubit (e.g., devices 112, 114, and 116) control system 110 is configured to achieve the temperature range of the cryogenic control system (e.g., below 10K). As mentioned above, in one example, cooling system 120 may correspond to a cryogenic plate or another type of cooling system (e.g., a liquid helium pipe or other such cooling system).
[0033]
[0038] When the flexible circuit portion 150 is wired from the control system 110 to the qubit surface 170, the cooling system 330 can be coupled to the flexible circuit portion 150 to thermally neutronize it. In this example, a thermal clamp 310 can be used to clamp (or otherwise attach) it to the flexible circuit portion 150. The cooling system 330 can be coupled to the flexible circuit portion 150 via the thermal clamp 310 and a physical connector 320. The cooling system 330 coupled to the flexible circuit portion 150 is configured to achieve the same (or similar) temperature range (e.g., less than 100 mK) as the qubit surface. A cooling system 160 coupled to the qubit surface 170, which has an integrated circuit chip containing a rigid circuit portion 170 and qubits (e.g., qubit devices 172, 174, and 176), is configured to achieve the temperature range of the qubit surface (e.g., less than 100 mK). Each of the cooling systems 160 and 330 may include a dilution refrigerator, a pump-operated helium-3 refrigerator, or a pump-operated helium-4 refrigerator. The same dilution refrigerator can be used for both the cooling system 160 and the cooling system 330. The dilution refrigerator can be configured by setting various parameters of the heat exchanger, including the shape of the mixing chamber, the flow impedance, the ratio of 3He to 4He, and the flow rate of the mixture.
[0034]
[0039] An advantage is that by using superconducting rigid-flex circuits to physically separate the qubits from the qubit control system, these subsystems do not need to coexist on the same geometric plane, while simultaneously providing thermal isolation. In addition, using superconducting rigid-flex circuits enables PCB-level wiring density without the need for connectors to connect the control system and the qubit device, respectively. The three cooling systems can be part of a single dilution refrigerator, provided that heat leakage from the cryogenic plate to the mixing chamber plate is within the specifications of the mixing chamber. If heat leakage is too large, the cryogenic plate can be used to cool the control system, or different dilution refrigerators can be used as cooling systems for the qubit surface. Furthermore, if necessary, a separate dilution refrigerator can be used to thermally neutronize the flexible circuit portion. An advantage is that, as with system 100 described with respect to Figure 1, system 300 and the method for operating this system support high-density interconnections over relatively long distances and high thermal gradients. High thermal gradients between high and low temperature areas are possible without the need for special substrates such as Macol. As a result, system 300 provides a means of using a single cold finger with a more uniform magnetic field compared to having multiple cold fingers, which would require larger magnets and apertures and complicate the positioning of quantum devices.
[0035]
[0040] Furthermore, as described with respect to system 100 in Figure 1, the qubit can be read as part of system 300 by coupling the qubit to a resonator such that the resonant frequency is shifted differently depending on the two different states of the qubit. For example, the frequency change can be detected by measuring the phase of a microwave pulse using the resonator. An increase in electron temperature caused by the injection of high-temperature electrons from the control system 110 to the qubit surface 170 can cause diffusion of the resonant function due to noise. Isolation between the control system 110 and the qubit surface 170, provided by the flexible circuit section 150 (which has a separate cooling system), also helps prevent such noise-related problems by minimizing the effect of high-temperature electrons on the performance of the qubits in the qubit surface 170. Figure 3 shows that system 300 includes certain components arranged in a particular way, but system 300 may include additional components with different arrangements or fewer components. For example, the control chip may be coupled to the rigid circuit section 130 in a different coupling type than shown in Figure 3. Similarly, the qubit chip can be coupled to the rigid circuit portion 180 in a manner different from the coupling type shown in Figure 3.
[0036]
[0041] Figure 4 shows the thermal resistance model 400 of system 300 in Figure 3. Similar to the thermal resistance model 200 in Figure 2, each resistor (R) in this thermal resistance model 400 FLEXIBLE CIRCUIT , R CONTROL , and R QUBIT) represents a certain amount of thermal resistance, and the current flowing through the resistor can be considered as the amount of heat flowing through the resistor. The thermal resistance model 400 further includes a first cooling system node 430, a second cooling system node 435, and another cooling system node 440. In this model, a node labeled control system node 410 corresponds to the temperature of the rigid circuit portion (e.g., rigid circuit portion 110 in Figure 3) and the control circuits for controlling the qubit, and another node labeled qubit node 420 corresponds to the temperature of another rigid circuit portion (e.g., rigid circuit portion 170 in Figure 3) and the qubit surface. The thermal resistance model 400 further includes a node labeled flexible circuit node 415, which corresponds to the flexible circuit portion 150 in Figure 3.
[0037]
[0042] The performance of system 300 in Figure 3 can be evaluated and improved by calculating heat transfer across regions using the thermal resistance model 400. Despite a large temperature gradient between the control system node 410 and the qubit node 420, most of the heat dissipated by the control system node 410 flows to the cooling system node 430. As mentioned earlier, this approach is facilitated by using an anisotropic thermal conduction substrate where heat transport is perpendicular rather than horizontal to the device being cooled. All additional heat further flows from the flexible circuit node 415 to the cooling system node 435. This facilitates independent heat removal from these two nodes while minimizing heat flow between the control system node 410 and the qubit node 440. Although not shown in Figure 4, additional temperature stages and thermal resistance modeling of the cooling system may also be performed.
[0038]
[0043] Figure 5 shows a side view 500 of a superconducting rigid-flex circuit for use with the systems of Figures 1 and 2. The superconducting rigid-flex circuit is shown to include a rigid circuit portion 510, a flexible circuit portion 530, and another rigid circuit portion 550. The flexible circuit portion 530 is shown to be formed of multiple layers of various materials, including superconducting metal interconnect layers 532 and 534. As shown in Figure 5, the interconnect layer 532 is formed to be integrated with both rigid circuit portions 510 and 550 such that a first portion 542 of the interconnect layer 532 extends into the rigid circuit portion 510 and a second portion 562 of the interconnect layer 532 extends into the rigid circuit portion 550. Similarly, the interconnection layer 534 is formed to be integrated with both rigid circuit portions 510 and 550 such that a first portion 544 of the interconnection layer 534 extends into the rigid circuit portion 510 and a second portion 564 of the interconnection layer 534 extends into the rigid circuit portion 550. By forming the superconducting rigid-flex circuit in this manner, no connectors are required to connect the rigid circuit portion to the flexible circuit portion. The rigid circuit portion may include additional superconducting interconnection layers or other conductive (e.g., non-superconducting metal) layers. The rigid circuit portion may also include non-superconducting layers and insulating layers to separate the conductive layers. As an example, the rigid circuit portion 510 shows non-superconducting metal layers 512 and 514. The rigid circuit portion 510 further shows insulating layers 514 and 518. Similarly, the rigid circuit portion 550 shows non-superconducting metal layers 552 and 556. The rigid circuit portion 550 represents non-superconducting metal layers 554 and 558.
[0039]
[0044] An advantage of forming superconducting rigid-flex circuits in this way is that PCB-level wiring density is possible without connectors. Figure 5 shows a superconducting rigid-flex circuit having a certain number of components arranged in a particular way, but a superconducting rigid-flex circuit can include additional components with different arrangements or have fewer components. For example, Figure 5 shows rigid circuit portions 510 and 550 having similar layers, but they could also have different numbers of layers and layers with different arrangements. In addition, additional rigid circuit portions and / or flexible circuit portions may be included as part of the superconducting rigid-flex circuit.
[0040]
[0045] Continuing to refer to Figure 5, superconducting rigid-flex circuits can be formed using printed circuit board (PCB) manufacturing techniques. For example, a superconducting rigid-flex PCB can be formed by creating various layers on a substrate. Next, a circuit pattern can be formed using laser imaging or photoimaging. Additional processing steps can be performed to ensure performance in the aforementioned cryogenic environment.
[0041]
[0046] Figure 6 shows a side view 600 of the rigid circuit portion 630 of a superconducting rigid-flex circuit for use with the systems of Figures 1 and 2. The rigid circuit portion 630 is shown with copper columns 632, 634, 636, and 638 that transfer heat perpendicularly toward the cooling system. Although not shown in Figure 6, a PCB layer may also be formed to allow thermal anisotropy, so that heat from devices 612, 614, and 616 is transferred perpendicularly toward the cooling system 620.
[0042]
[0047] In conclusion, the present disclosure relates to a system comprising a qubit surface having at least one qubit chip associated with a first rigid circuit portion of a superconducting rigid-flex circuit. The system may further include a first cooling system capable of operating the qubit surface and the first rigid circuit portion of the superconducting rigid-flex circuit at a temperature of 100 millikelvin or less.
[0043]
[0048] The system may further include a control system having at least one control chip associated with a second rigid circuit portion of the superconducting rigid-flex circuit. The system may further include a second cooling system capable of operating to maintain the operating temperature of the second rigid circuit portion of the superconducting rigid-flex circuit below 10 Kelvin, so that at least one control chip can dissipate heat to the second cooling system within a thermal budget commensurate with the amount of power required to supply control signals and control qubits in at least one qubit chip. The system may further include a flexible circuit portion of the superconducting rigid-flex circuit for interconnecting a first rigid circuit portion of the superconducting rigid-flex circuit with a second rigid circuit portion of the superconducting rigid-flex circuit.
[0044]
[0049] The first cooling system may include a dilution refrigerator, a pumped helium-3 system, or a pumped helium-4 system, and the second cooling system may include a cryogenic plate. The superconducting rigid-flex circuit may include a single printed circuit board.
[0045]
[0050] The flexible circuit portion of the superconducting rigid-flex circuit can be configured such that at least a subset of interconnection layers formed within the flexible circuit portion extends into the first rigid circuit portion and the second rigid circuit portion, respectively, thereby enabling interconnection between the first and second rigid circuit portions. The subset of interconnection layers may include superconducting metals.
[0046]
[0051] The qubits may include topological qubits that operate in a magnetic field, and the second rigid circuit portion may be mounted on a cold finger surrounded by magnets. The first cooling system may be independent of the second cooling system.
[0047]
[0052] In another example, the present disclosure relates to a method comprising providing a qubit surface having at least one qubit chip associated with a first rigid circuit portion of a superconducting rigid-flex circuit. The method may further include using a first cooling system to maintain the operating temperature of the qubit surface and the first rigid circuit portion of the superconducting rigid-flex circuit below 100 millikelvin.
[0048]
[0053] The method may further include providing a control system having at least one control chip associated with a second rigid circuit portion of the superconducting rigid-flex circuit. The method may further include using the control system and a second cooling system that maintains the operating temperature of the second rigid circuit portion of the superconducting rigid-flex circuit below 10 Kelvin, so that the control chip can dissipate heat to the second cooling system within a thermal budget commensurate with the amount of power required to supply control signals and control qubits in at least one qubit chip. The method may further include providing a flexible circuit portion of the superconducting rigid-flex circuit for interconnecting a first rigid circuit portion of the superconducting rigid-flex circuit with a second rigid circuit portion of the superconducting rigid-flex circuit.
[0049]
[0054] The first cooling system may include a dilution refrigerator, a pumped helium-3 system, or a pumped helium-4 system, and the second cooling system may include a cryogenic plate. The superconducting rigid-flex circuit may include a single printed circuit board.
[0050]
[0055] The flexible circuit portion of the superconducting rigid-flex circuit can be configured such that at least a subset of interconnection layers formed within the flexible circuit portion extends into the first rigid circuit portion and the second rigid circuit portion, respectively, thereby enabling interconnection between the first and second rigid circuit portions. The subset of interconnection layers may include superconducting metals.
[0051]
[0056] The qubits may include topological qubits that operate in a magnetic field, and the second rigid circuit portion may be mounted on a cold finger surrounded by magnets. The first cooling system may be independent of the second cooling system.
[0052]
[0057] In yet another example, this disclosure relates to a system configured to operate in a cryogenic environment, wherein the cryogenic environment is 10 -3 From Toru 10 -10 The system has a vacuum having a pressure in the range of Torr. The system may further include a qubit surface having a qubit chip associated with a first rigid circuit portion of the superconducting rigid-flex circuit. The system may further include a first cooling system capable of operating the qubit surface and the first rigid circuit portion of the superconducting rigid-flex circuit below 100 millikelvin.
[0053]
[0058] The system may further include a control system having a control chip associated with a second rigid circuit portion of the superconducting rigid-flex circuit. The system may further include a second cooling system capable of operating to maintain the operating temperature of the control system and the second rigid circuit portion of the superconducting rigid-flex circuit below 10 Kelvin, so that the control chip can supply control signals to dissipate heat to the second cooling system within a thermal budget commensurate with the amount of power required to control the qubits in the qubit chip.
[0054]
[0059] The system may further include a flexible circuit portion of the superconducting rigid-flex circuit for interconnecting a first rigid circuit portion of the superconducting rigid-flex circuit with a second rigid circuit portion of the superconducting rigid-flex circuit, but for thermal insulation. The system may further include a third cooling system capable of operating to maintain the operating temperature of the flexible circuit portion within the range of 100 millikelvin to 10 Kelvin.
[0055]
[0060] The second cooling system may include a cryogenic plate, and the first and third cooling systems may each include a dilution refrigerator, a pumped helium-3 system, or a pumped helium-4 system. The flexible circuit portion of the superconducting rigid-flex circuit can be configured such that at least a subset of the interconnection layers formed within the flexible circuit portion extends into the first rigid circuit portion and the second rigid circuit portion, respectively, thereby enabling interconnection between the first and second rigid circuit portions.
[0056]
[0061] Multiple interconnection layers can include a superconducting metal. The qubits can include topological qubits that operate in a magnetic field, and the second rigid circuit portion can be mounted on a cold finger surrounded by magnets.
[0057]
[0062] It should be understood that the methods, modules, and components described herein are merely illustrative. Alternatively, or additionally, the functionality described herein can be performed, at least in part, by one or more hardware logic components. For example, but not limited to, exemplary types of hardware logic components that can be used include field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standards (ASSPs), system-on-chip systems (SOCs), and complex-programmable logic devices (CPLDs). In an abstract but still clear sense, arrangements of components to achieve the same functionality are effectively “associated” in such a way that the desired functionality is achieved. Thus, any two components combined herein to achieve a particular functionality can be considered “associated” with each other, regardless of architecture or intermediate components, in such a way that the desired functionality is achieved. Similarly, any two components thus associated can be considered “operably connected” or “joined” with each other in such a way that the desired functionality is achieved.
[0058]
[0063] Furthermore, those skilled in the art will recognize that the boundaries between the functionalities of the aforementioned actions are merely illustrative. Functionalities of multiple actions can be combined into a single action, and / or the functionality of a single action can be distributed to additional actions. Moreover, alternative embodiments may include multiple instances of a particular action, and the order of actions may be modified in various other embodiments.
[0059]
[0064] While this disclosure provides specific examples, various modifications and changes can be made without departing from the scope of this disclosure as set forth in the following claims. For this reason, this specification and the drawings are intended to be illustrative rather than restrictive, and all such modifications are intended to be within the scope of this disclosure. No benefit, advantage, or solution to a problem described herein in relation to a specific example is intended to be construed as an important, essential, or intrinsic feature or element of any or all of the claims.
[0060]
[0065] Furthermore, as used herein, the term “one (a or an)” is defined as one or more. Also, the use of introductory phrases such as “at least one” and “one or more” in the claims shall not be construed as suggesting that the introduction of an element of another claim by the indefinite article “one (a or an)” limits any particular claim containing such introduced element to an invention containing only one such element, even if the same claim contains the introductory phrase “one or more” or “at least one” and an indefinite article such as “one (a or an)”. The same applies to the use of definite articles.
[0061]
[0066] Unless otherwise specified, terms such as "first" and "second" are used to appropriately distinguish the elements they describe. Therefore, these terms are not necessarily intended to indicate any temporal or other priority order of such elements.
Claims
1. System (100), A qubit surface (170) having at least one qubit chip (172) associated with the first rigid circuit portion (180) of a superconducting rigid-flex circuit (130, 150, and 180), A first cooling system (160) capable of operating to maintain the operating temperature of the qubit plane (170) and the first rigid circuit portion (180) of the superconducting rigid-flex circuit (130, 150, and 180) at 100 millikelvin or less, A control system (110) having at least one control chip (112) associated with the second rigid circuit portion (130) of the superconducting rigid-flex circuit (130, 150, and 180), The control system (110) and the second rigid circuit portion of the superconducting rigid-flex circuits (130, 150, and 180) are operable to maintain the operating temperature of the second rigid circuit portion below 10 Kelvin, so that the at least one control chip (112) can dissipate heat to the second cooling system (120) within a thermal budget commensurate with the amount of power required to supply control signals to control the qubits in the at least one qubit chip (172), and the second cooling system (120) The flexible circuit portion (150) of the superconducting rigid-flex circuit (130, 150, and 180) is used to interconnect the first rigid circuit portion (180) of the superconducting rigid-flex circuit (130, 150, and 180) with the second rigid circuit portion (130) of the superconducting rigid-flex circuit (130, 150, and 180), A system (100) including the above.
2. The system according to claim 1, wherein the first cooling system includes a dilution refrigerator, a pump-type helium 3 system, or a pump-type helium 4 system, and the second cooling system includes a cryogenic plate.
3. The system according to claim 1, wherein the superconducting rigid-flex circuit includes a single printed circuit board.
4. The system according to claim 1, wherein the flexible circuit portion of the superconducting rigid-flex circuit is formed such that at least a subset of a plurality of interconnection layers formed within the flexible circuit portion extends into the first rigid circuit portion and the second rigid circuit portion, respectively, thereby enabling interconnection between the first rigid circuit portion and the second rigid circuit portion.
5. The system according to claim 4, wherein the subset of the plurality of interconnection layers includes a superconducting metal.
6. The system according to claim 1, wherein the qubit includes a topological qubit that operates in a magnetic field, and the second rigid circuit portion is mounted on a cold finger surrounded by a magnet.
7. The system according to claim 1, wherein the first cooling system is independent of the second cooling system.
8. It is a method, A qubit surface (170) having at least one qubit chip (172) associated with the first rigid circuit portion (180) of the superconducting rigid-flex circuit (130, 150, and 180), The first cooling system (160) is used to maintain the operating temperature of the qubit surface (170) and the first rigid circuit portion (180) of the superconducting rigid-flex circuit (130, 150, and 180) at 100 millikelvin or less. A control system (110) is provided having at least one control chip (112) associated with the second rigid circuit portion (130) of the superconducting rigid-flex circuit (130, 150, and 180), By using the control system (110) and a second cooling system (120) that maintains the operating temperature of the second rigid circuit portion (130) of the superconducting rigid-flex circuit (130, 150, and 180) at 10 Kelvin or less, the control chip (112) is enabled to dissipate heat to the second cooling system (120) within a thermal budget commensurate with the amount of power required to supply control signals and control the qubits in the at least one qubit chip (172), A flexible circuit portion (150) of the superconducting rigid-flex circuit (130, 150, and 180) is provided to interconnect the first rigid circuit portion (180) of the superconducting rigid-flex circuit (130, 150, and 180) with the second rigid circuit portion (130) of the superconducting rigid-flex circuit (130, 150, and 180), A method that includes this.
9. The method according to claim 8, wherein the first cooling system includes a dilution refrigerator, a pump-type helium 3 system, or a pump-type helium 4 system, and the second cooling system includes a cryogenic plate.
10. The method according to claim 8, wherein the superconducting rigid-flex circuit includes a single printed circuit board.
11. The method according to claim 8, wherein the flexible circuit portion of the superconducting rigid-flex circuit is formed such that at least a subset of a plurality of interconnection layers formed within the flexible circuit portion extends into the first rigid circuit portion and the second rigid circuit portion, respectively, thereby enabling interconnection between the first rigid circuit portion and the second rigid circuit portion.
12. The method according to claim 11, wherein the subset of the plurality of interconnection layers includes a superconducting metal.
13. The method according to claim 8, wherein the qubit includes a topological qubit that operates in a magnetic field, and the second rigid circuit portion is mounted on a cold finger surrounded by a magnet.
14. The method according to claim 8, wherein the first cooling system is independent of the second cooling system.