Low-temperature voltage control system and quantum computer system

Abstract

The invention discloses a low-temperature voltage control system and a quantum computer system, and the system comprises a system module, one side of the system module is provided with a heating module, and the heating module is connected with a temperature control module and controls the system module to adjust the temperature; and the system module is provided with a Josephson junction voltage standard component, the Josephson junction voltage standard component is electrically connected with the quantum chip, and the input voltage of the quantum chip is controlled according to the temperature deviation. According to the control system, through the temperature control module and the heating module, the control system is fused with a dilution refrigerating environment, the control system is calibrated in the operation process of the dilution refrigerating machine, and it is ensured that stable electric signals can be provided for the quantum computer.

Description

Technical Field

[0001] The present invention relates to the field of quantum computer cryogenic systems, and in particular to a cryogenic voltage control system and a quantum computer system. Background Art

[0002] Whether it is to complete physical experiments in the 10mk-1K temperature range, to develop a low-temperature voltage reference for a quantum information measurement and control system based on CMOS technology, or to measure the noise of a low-temperature amplifier based on HEMT (High electron mobility transistor), a voltage reference is needed to calibrate the signal parameters in the information system. Choosing a voltage reference at room temperature or with an independent cryostat will inevitably introduce voltage errors caused by thermoelectromotive force noise or other noise.

[0003] The Josephson junction voltage standard can use quantum mechanisms to generate a sufficiently stable standard reference voltage. Based on this Josephson junction voltage standard, a programmable Josephson junction voltage standard device can be designed as a low-temperature voltage reference in the range of 1mV-1V to accurately evaluate the output voltage. The existing solution is based on this voltage component, combined with systems such as the Dewar tank, to provide a Josephson junction standard voltage system that can stably output standard voltage and current to the outside. The system places the Josephson junction voltage standard junction in a liquid helium Dewar tank in a 4K environment, uses an external power supply to power it, and then uses a superconducting cable to output the current as a standard voltage.

[0004] However, in this solution, the cooling environment is an independent cooling system of approximately 4K, which cannot be integrated with cooling environments such as superconducting quantum computing, and the output standard voltage can only power electronic devices at room temperature. Summary of the invention

[0005] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a low-temperature voltage control system and a quantum computer system.

[0006] In order to achieve the above object, the present invention adopts the following technical solution: a low temperature voltage control system, comprising:

[0007] System Modules,

[0008] A heating module is provided on one side of the system module, and the heating module is connected to the temperature control module to control the system module to adjust the temperature;

[0009] The system module is provided with a Josephson junction voltage standard component, the Josephson junction voltage standard component is electrically connected to the quantum chip, and the input voltage of the quantum chip is controlled according to the temperature deviation.

[0010] As a further description of the above technical solution: the system module also includes a voltage detection module, a power supply module, a microwave transmission module or a temperature control module, and is electrically connected via a cable.

[0011] As a further description of the above technical solution: set a standard voltage and a temperature detection threshold, detect the deviation of the Josephson junction standard component from the temperature detection threshold at the standard voltage, read the characteristic parameters of the system module, use the characteristic parameters as driving parameters of the control system, and control the input voltage of the quantum chip.

[0012] As a further description of the above technical solution: the Josephson junction voltage standard component is a programmable Josephson junction voltage standard component.

[0013] As a further description of the above technical solution: the cable is connected to the connecting component on the top of the dilution refrigerator to share the ground.

[0014] As a further description of the above technical solution: the temperature detection threshold of the Josephson junction under the standard voltage is [4.05K, 3.95K].

[0015] Also included is a quantum computer system, which is applicable to any low-temperature voltage control system in the above technical solutions, including:

[0016] Dilution refrigerator and chip loading structure;

[0017] The dilution refrigerator is provided with a plurality of cold plates, and the plurality of cold plates are arranged in sequence with gradually decreasing temperatures;

[0018] A connecting component is arranged on the top of the dilution refrigerator, and a voltage detection module, a power supply module, a temperature control module and a microwave emission module are integrated or independently arranged on the connecting component, one side of which is connected to the system module through a cable, and the other side shares a common ground.

[0019] As a further description of the above technical solution: the dilution refrigerator comprises a first cold plate, a second cold plate and a third cold plate, and the system module is arranged at the second cold plate.

[0020] As a further description of the above technical solution: heat anchors are provided at some of the cold plates, and cables are sequentially passed through the heat anchors and are installed on the first cold plate, the second cold plate and the third cold plate.

[0021] As a further description of the above technical solution: the chip loading structure is arranged at the third cold plate, the chip loading structure comprises a box body, the inner side of the box body is integrated with a Josephson junction voltage standard component, the box body is connected to the second cold plate through a heat shield isolator, a through hole is provided on the box body, a heat insulating gasket is provided inside the through hole, and the cable passes through the through hole and extends to the third cold plate;

[0022] When the chip loading structure is in a state where a quantum chip is installed, the stability of the control system is evaluated; when the chip loading structure is in a state where a quantum chip is not installed, the control system is evaluated through the stability of the quantum bit.

[0023] The above technical solution has the following advantages or beneficial effects:

[0024] 1. Through the temperature control module and the heating module, the control system is integrated with the dilution refrigeration environment to ensure that the entire control system can be integrated into the dilution refrigeration environment. At the same time, the control system is calibrated during the operation of the dilution refrigerator to ensure that it can provide a stable electrical signal for the quantum computer.

[0025] 2. According to the actual working environment and signal requirements of quantum computers, combined with the dilution refrigerator structure, the overall architecture solution has been improved. The heat anchor is used to enable heat exchange between the cable and the environment inside the dilution refrigerator, thereby reducing the room temperature thermal noise carried by the cable during transmission and ensuring the accuracy of signal transmission by the dilution refrigerator in a low-temperature environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of the control system proposed by the present invention;

[0027] Figure 2 It is a schematic diagram of the system module of the present invention being arranged at a cold plate;

[0028] Figure 3 for Figure 2 A partial enlarged view of the system module at point A in the middle.

[0029] Legend:

[0030] 1. System module; 2. Heating module; 3. Temperature control module; 4. Voltage detection module; 5. Power module; 6. Microwave emission module; 7. Quantum chip; 8. Flange; 9. First cold plate; 10. Second cold plate; 11. Third cold plate; 12. Thermal anchor; 13. Josephson junction voltage standard component; 14. Box body; 15. Thermal shield isolation component; 16. Through hole. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Reference Figure 1 , an embodiment provided by the present invention: a low temperature voltage control system and a quantum computer system, comprising:

[0033] System Modules,

[0034] A heating module is provided on one side of the system module, the heating module is connected to the temperature control module, and the system module is controlled to adjust the temperature;

[0035] The system module is provided with a Josephson junction voltage standard component, which is electrically connected to the quantum chip and controls the input voltage of the quantum chip according to the temperature deviation.

[0036] The system module also includes a voltage detection module, a power supply module, a microwave emission module or a temperature control module, and is electrically connected via cables.

[0037] In this embodiment, a heating module is provided on the top of the system module, and the heating module is connected to the temperature control module. The temperature control module controls the heating module to heat and raise the temperature of the system module to room temperature (25°C). The heating module can be a thermocouple, a heating electrode, etc. The voltage detection module can be a digital voltmeter, a multimeter, etc. The power module is used to provide direct current for power supply. Through the temperature control module and the heating module, the control system is integrated with the dilution refrigeration environment. The control system is calibrated during the operation of the dilution refrigerator to ensure that a stable electrical signal can be provided for the quantum computer.

[0038] Through the temperature control module and the heating module, the control system is integrated with the dilution refrigeration environment. The heating module is controlled to heat up the system module below to room temperature (25°C). The voltage detection module and the microwave emission module are used to detect the noise when the system module voltage is stable at room temperature. After starting the dilution refrigerator, the system module is cooled down and the noise when the system module voltage is stable in the 4K temperature zone is detected. The room temperature thermal noise carried by the cable when the system module is powered is obtained. The cable is cooled down by setting a thermal anchor at the cold plate to reduce the room temperature thermal noise carried by the cable, thereby ensuring the accuracy of signal transmission of the dilution refrigerator in a low temperature environment.

[0039] Thermometers are installed on the top of the system module and at the Josephson junction voltage standard to detect the temperature, and the temperature is fed back to the temperature control module for temperature control adjustment.

[0040] The voltage detection module is used to detect whether the voltage of the system module is stable. If it is stable, the characteristic parameters are output. If it is unstable, it is adjusted by adjusting the DC current of the power module and the transmission signal of the microwave transmission module.

[0041] Set the standard voltage and temperature detection threshold, detect the deviation between the Josephson junction standard and the temperature detection threshold at the standard voltage, read the characteristic parameters of the system module, use the characteristic parameters as the driving parameters of the control system, and control the input voltage of the quantum chip. The temperature detection threshold of the Josephson junction at the standard voltage is [4.05K, 3.95K].

[0042] In this embodiment, after the actual installation is completed, the system stability is evaluated from the temperature and voltage characteristics. The standard voltage is 10V, the temperature detection threshold is [4.05K, 3.95K], the temperature deviation allowed by the Josephson junction voltage standard under the condition of 10V voltage output is within ±50mK, and the order uncertainty is 10nV. By calibrating the cooling power of the Josephson junction voltage standard, when the output deviation of the Josephson junction voltage standard is the minimum voltage position, the corresponding characteristic parameter is the optimal environmental parameter, and the characteristic parameters (driving frequency, power and ambient temperature) are measured. The characteristic parameters are used as the driving parameters of the control system to provide corresponding voltage standard signals for power supply to the electronic devices or quantum chips at the cold plate in the quantum computer.

[0043] The Josephson junction voltage standard is a programmable Josephson junction voltage standard. The cable is connected to the connection component on the top of the dilution refrigerator for common grounding.

[0044] In this embodiment, the connecting component is a flange, and a Josephson junction voltage standard component is integrated inside the box body to form a programmable Josephson junction voltage standard component. The microwave transmitting module sends a microwave pulse signal to the Josephson junction voltage standard component to drive the system module to operate.

[0045] Reference Figure 2-Figure 3 , and also includes a quantum computer system, which is applicable to any low-temperature voltage control system in the above technical solutions, including:

[0046] Dilution refrigerator and chip loading structure;

[0047] The dilution refrigerator is provided with a plurality of cold plates, which are arranged in sequence with gradually decreasing temperatures;

[0048] A connecting component is provided on the top of the dilution refrigerator, and a voltage detection module, a power module, a temperature control module and a microwave transmission module are integrated or independently provided on the connecting component, one side is connected to the system module through a cable, and the other side shares a common ground.

[0049] In this embodiment, the voltage detection module, the power supply module, the temperature control module and the microwave emission module are respectively arranged on the flange, and can also be integrated as an external control module to control the control system.

[0050] It is connected to the system module through a cable. A capacitor is also set between the system module and the microwave generating module to isolate the DC signal and avoid introducing large noise into the dilution refrigerator. The outer conductor of the cable is connected and grounded through the flange at the top, and the other end is connected to the system module.

[0051] The dilution refrigerator comprises a first cold plate, a second cold plate and a third cold plate, and the system module is arranged at the second cold plate.

[0052] In this embodiment, the first cold plate is in the 60K temperature zone, the second cold plate is in the 4K temperature zone, and the third cold plate is in the MC temperature zone. The system module is set in the 4K temperature zone to adapt to the ambient temperature inside the dilution refrigerator, so that the ambient temperature of the system module is consistent with the temperature of the dilution refrigerator, ensuring that the output characteristic parameters are more accurate.

[0053] Heat anchors are arranged at several cold plates, and cables are sequentially passed through the heat anchors and installed on the first cold plate, the second cold plate and the third cold plate.

[0054] In this embodiment, heat anchors are provided at both the first cold plate and the second cold plate, and the cable is arranged on the first cold plate and the second cold plate through the heat anchors. The heat anchors enable the cable to exchange heat with the environment in the dilution refrigerator, thereby reducing the room temperature thermal noise carried by the cable during transmission. The cable can use the RF cable inside the dilution refrigerator.

[0055] The chip loading structure is arranged at the third cold plate, and the chip loading structure comprises a box body, the Josephson junction voltage standard part is integrated inside the box body, the box body is connected to the second cold plate through a heat shield isolator, a through hole is provided on the box body, a heat insulating gasket is arranged inside the through hole, and the cable passes through the through hole and extends to the third cold plate;

[0056] When the chip loading structure is in the state of installing a quantum chip, the quantum chip is used to evaluate the stability of the control system. When the chip loading structure is not installed with a quantum chip, the stability of the control system is evaluated from the temperature and voltage characteristics through the designed overall architecture of the dilution refrigerator. The evaluation method of the control system stability is more flexible and can ensure the provision of stable electrical signals.

[0057] The chip loading structure includes a box body, the inner side of which is integrated with a Josephson junction voltage standard component, and a microwave transmitting module transmits a microwave pulse signal to drive the system module to operate.

[0058] The box body is connected to the second cold plate through a heat shield isolator made of epoxy glass. A through hole is opened on the box body. An insulating gasket is arranged inside the through hole. The insulating gasket is made of plastic. The cable passes through the through hole and extends to the third cold plate.

[0059] A quantum chip is arranged on the third cold plate, and the quantum chip is connected to the system module via a cable.

[0060] In this embodiment, the heat shield isolation component is a cover plate arranged above the box body, and a plurality of connecting tubes extending outward are arranged on the cover plate. A connecting plate is provided at the other end of the connecting tube. The connecting plate and the groove on the cold plate are limitedly matched to realize the installation of the box body.

[0061] A through hole is opened on the box body to allow the cable to pass through the box body and connect to the Josephson junction voltage standard component inside. The output end cable of the Josephson junction voltage standard component extends from the bottom of the box body and connects to the quantum chip at the third cold plate. The characteristic parameters of the Josephson junction voltage standard component after adjustment are used as driving parameters.

[0062] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A low temperature voltage control system, characterized in that: include: System Modules, A heating module is provided on one side of the system module, and the heating module is connected to the temperature control module to control the system module to adjust the temperature; The system module is provided with a Josephson junction voltage standard component, the Josephson junction voltage standard component is electrically connected to the quantum chip, and the input voltage of the quantum chip is controlled according to the temperature deviation.

2. The control system according to claim 1, characterized in that: The system module also includes a voltage detection module, a power supply module, a microwave emission module or a temperature control module, and is electrically connected via cables.

3. The control system according to claim 1, characterized in that: The standard voltage and temperature detection threshold are set, the deviation between the Josephson junction standard component and the temperature detection threshold under the standard voltage is detected, the characteristic parameters of the system module are read, and the characteristic parameters are used as driving parameters of the control system to control the input voltage of the quantum chip.

4. The control system according to claim 1, characterized in that: The Josephson junction voltage standard component is a programmable Josephson junction voltage standard component.

5. The control system according to claim 2, characterized in that: The cable is connected to the connection component on the top of the dilution refrigerator to share a common ground.

6. The control system according to claim 3, characterized in that: The temperature detection threshold of the Josephson junction under the standard voltage is [4.05K, 3.95K].

7. A quantum computer system, characterized in that: The quantum computer system is applicable to any one of the low temperature voltage control systems in claims 1 to 6, including: Dilution refrigerator and chip loading structure; The dilution refrigerator is provided with a plurality of cold plates, and the plurality of cold plates are arranged in sequence with gradually decreasing temperatures; A connecting component is arranged on the top of the dilution refrigerator, and a voltage detection module, a power supply module, a temperature control module and a microwave emission module are integrated or independently arranged on the connecting component, one side of which is connected to the system module through a cable, and the other side shares a common ground.

8. The quantum computer system according to claim 7, characterized in that: The dilution refrigerator comprises a first cold plate, a second cold plate and a third cold plate, and the system module is arranged at the second cold plate.

9. The quantum computer system according to claim 8, characterized in that: Heat anchors are provided at some of the cold plates, and cables are sequentially passed through the heat anchors and passed through the first cold plate, the second cold plate and the third cold plate.

10. The quantum computer system according to claim 8, characterized in that: The chip loading structure is arranged at the third cold plate, the chip loading structure comprises a box body, the Josephson junction voltage standard is integrated inside the box body, the box body is connected to the second cold plate via a heat shield isolator, a through hole is provided on the box body, a heat insulating gasket is arranged inside the through hole, and the cable passes through the through hole and extends to the third cold plate; When the chip loading structure is in a state where a quantum chip is installed, the stability of the control system is evaluated; when the chip loading structure is in a state where a quantum chip is not installed, the control system is evaluated through the stability of the quantum bit.

Images