Method for reducing heating of microwave switch and application thereof

Abstract

The invention discloses a method for reducing heating of a microwave switch, and belongs to the technical field of quantum chips. A method for reducing heating of a microwave switch comprises the following steps: providing a first voltage for the microwave switch to start the microwave switch according to a first resistance value of the microwave switch at a first temperature, and determining a corresponding starting threshold current; determining a second voltage for starting the microwave switch based on a second resistance value of the microwave switch at the second temperature and the starting threshold current; wherein the second temperature is lower than the first temperature; and at the second temperature, a second voltage is applied to the microwave switch, so that the microwave switch is started, and the current passing through the microwave switch is the starting threshold current. In this way, the heating value of the microwave switch in the dilution refrigerator can be reduced.

Description

Technical Field

[0001] This application belongs to the field of quantum chip technology, and in particular relates to a method for reducing the heating of microwave switches and its application. Background Technology

[0002] Quantum computing is a novel computing approach that utilizes the principles of superposition and entanglement in quantum mechanics to achieve computing power far exceeding that of classical computers. Currently, quantum computer research and development can be broadly categorized into two types: superconducting quantum computing and spin quantum computing based on semiconductor quantum dots. Both types rely on quantum chips as their core, while superconducting quantum computing requires an extremely low-temperature environment close to absolute zero to operate.

[0003] Currently, dilution refrigerators can maintain ultra-low temperature environments, approximately 10 mK to 20 mK (Kelvin), for extended periods. Ultra-low temperatures can effectively reduce the impact of environmental noise on superconducting quantum chips.

[0004] Typically, a superconducting quantum chip is installed in one of the temperature layers of a dilution refrigerator. In addition to the superconducting quantum chip, a microwave switch is also installed in this layer to extend the testing circuitry. However, due to the limited internal space of the dilution refrigerator, and the heat generated by the superconducting quantum chip and microwave switches during operation, the cooling capacity of each temperature layer is limited, thus affecting the temperature of the temperature zone and consequently the normal operation of the superconducting quantum chip. Therefore, it is necessary to reduce the heat dissipated by the microwave switch during operation. Summary of the Invention

[0005] The purpose of this application is to provide a method for reducing the heat generated by microwave switches, in order to solve the problem in the prior art that microwave switches generate a lot of heat in dilution refrigerators, which affects the temperature of the temperature zone and thus affects the normal operation of quantum chips. This method can reduce the heat dissipated into the environment when microwave switches are working.

[0006] To solve the above-mentioned technical problems, this utility model provides a method for reducing the heat generation of a microwave switch, comprising:

[0007] Based on the first resistance value of the microwave switch at the first temperature, a first voltage is provided to the microwave switch to start it, and the corresponding start-up threshold current is determined.

[0008] Based on the second resistance value of the microwave switch at a second temperature and the start-up threshold current, a second voltage for starting the microwave switch is determined; wherein the second temperature is lower than the first temperature;

[0009] At a second temperature, the second voltage is applied to the microwave switch, causing the microwave switch to start and the current through the microwave switch to be the start-up threshold current.

[0010] Preferably, the first temperature is 10℃-30℃;

[0011] The second temperature is 10mK-100mK.

[0012] Preferably, the method for obtaining the first voltage includes:

[0013] At a first temperature, a voltage with an initial value of zero and gradually increasing is provided to the microwave switch; the instantaneous voltage at which the microwave switch transitions from a stopped state to an activated state during this process is taken as the first voltage.

[0014] Preferably, applying the second voltage to the microwave switch includes: providing a power supply to power the microwave switch, wherein the voltage of the power supply is not less than the second voltage.

[0015] Preferably, the power supply for the microwave switch includes:

[0016] The microwave switch is powered by a power supply whose output voltage is the second voltage.

[0017] Preferably, the power supply for the microwave switch includes:

[0018] Provide a voltage divider resistor and connect it in series with the microwave switch;

[0019] The microwave switch is powered by a power supply with an output voltage greater than the second voltage, such that the voltage applied by the power supply to the microwave switch is the second voltage.

[0020] Preferably, the voltage divider resistor is an adjustable resistor.

[0021] Preferably, applying the second voltage to the microwave switch to activate the microwave switch, and ensuring that the current through the microwave switch is the activation threshold current, includes:

[0022] A voltage is applied to the microwave switch to perform a pulse test, in order to obtain the shortest pulse time that enables the microwave switch to start.

[0023] A second voltage with a duration of at least the shortest pulse time is applied to the microwave.

[0024] Preferably, the microwave switch is a mechanical switch based on electromagnetic induction.

[0025] The present invention also provides a method for heating a microwave switch, including any one of the foregoing embodiments, for the application of the microwave switch in controlling a superconducting quantum chip in a dilution refrigerator.

[0026] Compared with the prior art, this application determines the threshold current based on the first resistance value of the microwave switch (resistance value in a room temperature environment) and the first voltage that enables the microwave switch to start (voltage value in a room temperature environment), and then determines the second voltage (voltage value in a low temperature environment) based on the second resistance value (resistance value in a low temperature environment) and the threshold current. In the extremely low temperature environment of the dilution refrigerator, the second voltage is applied to the microwave switch to enable the microwave switch, and the current through the microwave switch is the threshold current. The threshold current is the minimum current that enables the microwave switch to work, which can reduce the heat generated by the microwave switch when it is working in the extremely low temperature space of the dilution refrigerator. Attached Figure Description

[0027] Figure 1 A schematic diagram of a quantum bit structure provided in an embodiment of this application;

[0028] Figure 2 This is a schematic diagram of the steps of a method for reducing microwave switch heating provided in an embodiment of this application;

[0029] Figure 3 This is a schematic diagram of a microwave switch structure provided in an embodiment of this application;

[0030] Figure 4 This is a schematic diagram of the steps for determining the starting threshold current provided in an embodiment of this application;

[0031] Figure 5 This is a schematic diagram of the step of applying a second voltage to a microwave switch provided in an embodiment of this application;

[0032] Figure 6 A schematic diagram illustrating the steps of providing power to a microwave switch according to an embodiment of this application;

[0033] Figure 7 A schematic diagram illustrating the steps of providing power to a microwave switch according to an embodiment of this application;

[0034] Figure 8 A schematic diagram is provided for the steps of obtaining and implementing the shortest pulse time in the embodiments of this application. Detailed Implementation

[0035] The specific embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. The advantages and features of the present invention will become clearer from the following description and claims. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0036] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0038] Quantum computing is a rapidly developing computing method that utilizes the principles of superposition and entanglement in quantum mechanics to achieve computing power far exceeding that of classical computers. Currently, quantum computer research and development can be mainly categorized into two types: superconducting quantum computing and spin quantum computing based on semiconductor quantum dots. The core of both types of computing is the quantum chip. Superconducting quantum computing requires an extremely low temperature environment close to absolute zero. In practical production applications, this extremely low temperature environment is typically provided by a dilution refrigerator. Dilution refrigerators can maintain extremely low temperatures for extended periods without negative influencing factors, possess significant cooling capacity, have a relatively simple structure and operation, and are unaffected by surrounding magnetic fields. Therefore, they can provide a good and stable extremely low temperature environment for the operation of superconducting quantum chips.

[0039] Currently, qubit structures often employ methods such as Figure 1 The diagram shows a single ground-connected capacitor and a superconducting quantum interference device (SQU). One end of the SQU is grounded, and the other end is connected to the ground-connected capacitor. This capacitor is typically a cross-shaped parallel plate capacitor. Notably, the cross-shaped capacitor plates are surrounded by a ground plane, and a gap is formed between the cross-shaped capacitor plates and the ground plane. One end of the SQU is connected to the cross-shaped capacitor plate, and the other end is connected to the ground plane. The cross-shaped capacitor plate has a first end and a second end for coupling connections. The first end is typically used to connect the SQU, and the second end is used to couple with readout structures such as resonant cavities. Additionally, a certain amount of space needs to be reserved near the first and second ends for wiring. For example, space needs to be reserved near the first end for arranging xy signal lines and z signal lines. The other two ends of the cross-shaped capacitor plate are used for coupling with adjacent qubits.

[0040] The quantum chip, a core component of a quantum computer, integrates multiple qubit structures and circuitry for controlling and reading qubit information. Superconducting quantum chips operate in the extremely low-temperature environment of a dilution refrigerator, where temperatures are typically only a few Kelvin or even milliKelvin. To facilitate the measurement and control of each qubit on the quantum chip, an electrical signal connection needs to be established between the signal measurement and control system (operating at room temperature) and the quantum chip. This connection can be achieved, for example, by connecting the signal ports of the quantum chip to the signal outputs or inputs of the signal measurement and control system via signal cables. However, as the number of qubits increases, the number of signal channels for establishing communication also increases. To alleviate the wiring pressure caused by the dramatic increase in the number of qubits, microwave switches are introduced into the chip transmission path from the signal measurement and control system to the quantum chip, allowing a single signal channel from the signal measurement and control system to transmit signals to multiple ports of the quantum chip.

[0041] Typically, when a quantum chip is placed in a dilution refrigerator, it is usually located in the MC (mixchamber), i.e., the mixing chamber. In addition, microwave switches and test circuits are also installed in the MC layer to ensure proper operation of the quantum chip and signal communication between devices. However, since each device in the dilution refrigerator generates heat during operation, it affects the properties of the cavity, such as the Q value. When the temperature rises significantly, it can even cause the superconducting circuitry and the quantum chip to lose their superconducting state, making the quantum chip's performance undetectable. Furthermore, when the temperature in the MC layer is too high, it will ultimately affect the state of the qubits, increasing the thermal excitation of the quantum chip and reducing its readout performance. Specifically, the dilution refrigerator has multiple cooling layers, each with limited cooling capacity and power. For example, the cooling power of the MC layer is 30 microwatts, which are unchangeable conditions. Meanwhile, the microwave switches have a room temperature resistance of approximately 220 ohms and a low-temperature resistance of approximately 5-10 ohms, with an operating voltage of 28V. Under normal use, they generate a large amount of heat, affecting the temperature of each layer in the dilution refrigerator and thus impacting the quantum chip's test performance, even causing damage.

[0042] For microwave switches, due to their 1-to-6 operating principle, the internal circuitry cannot be modified. The resistance of a microwave switch inherently differs between low and room temperature. Therefore, under the same voltage, the current flowing through the microwave switch differs between low and room temperature. The direct physical quantity that generates the operation of a microwave switch relay is current. Therefore, when the resistance decreases, to maintain the same current, a smaller voltage can be applied to the microwave switch.

[0043] In practical applications, microwave switches are used to group multiple microwave circuits onto a single line, similar to a single-pole multi-throw switch. For example, if there's one line on the left and six lines on the right, the microwave switch controls the connection between the left line and the six right lines. The difference is that microwave switches can conduct microwave signals, can be used for integrated distribution of microwave circuits, and don't need to operate continuously. They only require a specific power supply signal to complete the switching process, and their operation can be brief.

[0044] Please refer to Figure 2 This invention provides a method for reducing heat generation in microwave switches, comprising the following steps:

[0045] S1: Based on the first resistance value of the microwave switch at the first temperature, a first voltage is provided to the microwave switch to start it, and the corresponding start-up threshold current is determined;

[0046] S2: Based on the second resistance value of the microwave switch at the second temperature and the start-up threshold current, determine the second voltage for starting the microwave switch; wherein the second temperature is lower than the first temperature;

[0047] S3: At the second temperature, the second voltage is applied to the microwave switch, causing the microwave switch to start and the current through the microwave switch to be the start-up threshold current.

[0048] First, based on the first resistance value of the microwave switch at the first temperature, a first voltage is applied to the microwave switch to enable it and complete the switching process. After activation, the corresponding activation threshold current is determined. Then, based on the second temperature and the second resistance value of the microwave switch at the second temperature, and in conjunction with the activation threshold current, a second voltage is determined to enable the microwave switch. It is worth noting that the second temperature is lower than the first temperature. Finally, the microwave switch is placed at the second temperature, and the second voltage is applied to the microwave switch to enable it, and the current through the microwave switch is the aforementioned activation threshold current.

[0049] Regarding the aforementioned microwave switch, the inventors mainly used, for example... Figure 3 The microwave switch shown is a circuit structure with a conduction circuit having a general-purpose input port IN and six first-channel output ports spaced apart along a path from the input port on the conduction circuit; each of these first-channel output ports is also equipped with a second-channel output port numbered 1, 2, 3, 4, 5, and 6. The first-channel output ports and second-channel output ports are arranged adjacent to each other and in pairs.

[0050] To enable connection between a specific second channel output and the general-purpose input port IN, and to allow for disconnection when needed, while also considering ease of operation and speed, an electromagnetically based contactor—such as… Figure 3 The inverted "T" shaped structure in the text.

[0051] exist Figure 3 As shown in the schematic direction, when the contactor moves downward until it contacts the first and second channel output ports corresponding to the position, the first and second channel output ports are connected, thereby connecting the channel input port IN and the second channel output port. Conversely, when the contactor moves upward until it separates from the first and second channel output ports corresponding to the position, the first and second channel output ports are disconnected, thereby disconnecting the channel input port IN and the second channel output port.

[0052] From the perspective of the circuit control terminal or power supply terminal of the RF switch, it has a reset circuit RESET and a ground circuit -G (i.e., GND). A reset coil (or disconnect coil) is also connected between the reset circuit RESET and the ground circuit -G. In addition, the ground circuit is connected to an attraction coil, with each coil having a lead-out port. Figure 3 It has six ports, numbered +1, +2, +3, +4, +5, and +6 respectively.

[0053] The reset coil and the attraction coil are configured in pairs; in Figure 3 In the middle, the reset coil and the adsorption coil are located on the left and right sides of the inverted "T" shaped contactor.

[0054] exist Figure 1 In the RF switch circuit, the control process is as follows: When the -G port and RESET port are powered on, channels 1, 2, 3, 4, 5, and 6 are all turned off. When the -G port and +1 port are powered on, channel 1 is turned on; similarly, when the -G port and +2 port are powered on, channel 2 is turned on; similarly, when the -G port and +3 port are powered on, channel 3 is turned on. Furthermore, it is also possible to select that when the -G port and +1 or +2 ports are powered on, channels 1 and 2 are turned on. Therefore, in this circuit, all channels are turned off simultaneously, and one channel can be selected to be turned on, or two or more channels can be turned on simultaneously. However, in actual measurement, it can be controlled to ensure that only one channel is turned on.

[0055] Furthermore, the first temperature is 10℃-30℃, which is considered to be the room temperature, and the microwave switch is tested at this temperature to obtain its resistance value at the current temperature as the first resistance value; and, a voltage is applied to the microwave switch at the first temperature to start the microwave switch, and the minimum voltage required to start the microwave switch is calibrated as the first voltage; finally, the current flowing through the microwave switch when the first voltage is applied to the microwave switch at the first temperature is tested and defined as the start-up threshold current.

[0056] The second temperature is 10mK–100mK, which is the operating ambient temperature of the microwave switch in this application. This temperature is provided by a dilution cooler, specifically located in the MC layer of the cooler. At this temperature, the superconducting metal (qubit) is in a superconducting state, meaning its resistance decreases compared to the first temperature. For example, at the first temperature, the resistance to ground of each line of the microwave switch is approximately 200 ohms, while at the second temperature, its resistance drops to approximately 6 ohms. At this temperature, the resistance of the microwave switch needs to be measured and defined as the second resistance value. Then, combined with the start-up threshold current, the voltage that needs to be applied to the microwave switch at the second temperature is calculated and calibrated as the second voltage.

[0057] In fact, applying a second voltage to the microwave switch at the second temperature is not only necessary to activate the microwave switch, but also to ensure that the current flowing through the microwave switch is equal to the activation threshold current.

[0058] In one embodiment of this application, a method for obtaining a first voltage is disclosed, such as... Figure 4 As shown, the method includes:

[0059] S11: At a first temperature, a voltage with an initial value of zero and gradually increasing is provided to the microwave switch; the instantaneous voltage at which the microwave switch changes from a stopped state to a started state during this process is taken as the first voltage.

[0060] S12: Determine the start-up threshold current of the microwave switch based on the first resistance value of the microwave switch at the first temperature and the first voltage applied to the microwave switch.

[0061] At the first temperature, a power supply is provided to the microwave switch. This power supply outputs a voltage with an initial value of zero, which is linear and gradually increases. Based on practical experience, the instantaneous voltage at which the microwave switch transitions from a stopped state to a started state as the power supply voltage gradually increases is taken as the first voltage. It is important to note that the transition from a stopped state to a started state specifically refers to the disconnection or connection of the microwave switch's input port IN and different channel output ports, altering the microwave signal transmission path. The stopped state of the microwave switch is not practically used in the circuit (although it may have a conducting function).

[0062] In one embodiment of this application, the step of applying the second voltage to the microwave switch is as follows: Figure 5The following are included:

[0063] S31: Provide a power supply to power the microwave switch, wherein the voltage of the power supply is not less than the second voltage.

[0064] A power supply is provided and applied to the microwave switch to power it. It is worth noting that the voltage applied to the microwave switch by this power supply must be no less than a second voltage to include the voltage applied to the microwave switch by the power supply. This allows the microwave switch to be successfully started at the second temperature, that is, when this voltage is applied to the microwave switch, the current passing through the microwave switch is greater than the threshold current, which causes the conduction state controlled by the microwave switch to change.

[0065] Regarding the voltage mentioned above, further optimization of the voltage is possible. This includes the step of providing power to the microwave switch, such as... Figure 6 The following are included:

[0066] S31a: Power the microwave switch using a power supply whose output voltage is the second voltage.

[0067] That is, by calculation, the specific second voltage at the second temperature is obtained, and the power supply is adjusted so that the voltage applied to the microwave switch by the power supply output voltage is exactly the second voltage. More precise power supplies are required to make the above settings.

[0068] In addition, this application also provides an embodiment that provides a step of powering a microwave switch with a power source, such as... Figure 7 The following are included:

[0069] S31b:

[0070] Step 1: Provide a voltage divider resistor and connect it in series with the microwave switch;

[0071] Step 2: Power the microwave switch with a power supply whose output voltage is greater than the second voltage, so that the voltage applied by the power supply to the microwave switch is the second voltage.

[0072] This can be understood as follows: First, a resistor is provided in series with the microwave switch. This resistor has a voltage divider effect relative to the microwave switch. Then, a power supply is applied. The power supply applies a voltage to the circuit formed by the microwave switch and the voltage divider resistor. Part of the voltage of the power supply is applied to the voltage divider resistor, and the other part is applied to the microwave switch. The voltage value of the part of the voltage applied to the microwave switch is the second voltage.

[0073] Alternatively, it can be understood as selecting a power supply with a voltage value greater than the second voltage, knowing its voltage value, then adding a parallel resistor to the microwave switch, and calculating the specific resistance value of the voltage divider resistor using the power supply voltage value and the microwave switch resistance value.

[0074] Regarding the voltage divider resistors mentioned above, in order to simplify the selection of voltage divider resistors with different resistance values, an adjustable resistor can be used. The adjustable resistor is connected in series with the microwave switch, and the actual effective resistance of the adjustable resistor is adjusted according to the voltage value of the power supply, so that the voltage applied to the microwave switch by the power supply is the second voltage.

[0075] Compared to current conventional methods, the actual operating voltage of the microwave switch is reduced while the operating current remains normal (allowing the microwave switch to change its selected conduction state). Since the microwave switch operates on a 1-to-6 principle, its internal circuitry cannot be altered. The resistance of the microwave switch differs between room temperature and low temperature (first temperature and second temperature), so the current at the same voltage will definitely differ between low and room temperature. The direct physical quantity for the microwave switch relay to operate is current. Therefore, when the resistance decreases, either the voltage must be reduced, or a voltage divider resistor slightly smaller than the resistance of the microwave switch at room temperature must be added for voltage division. Thus, the microwave switch, adjusted according to the embodiments of this application, maintains the same efficiency but reduces power consumption, thereby reducing heat generation.

[0076] In response, the inventors of this application, through numerous experiments, discovered that by limiting and adjusting the voltage applied to the microwave switch, the heat generation can be significantly reduced by changing the on-time of the microwave switch. Specifically, the steps of applying a second voltage to the microwave switch to activate it, and ensuring that the current flowing through the microwave switch is the activation threshold current, are as follows: Figure 8 The following are included:

[0077] S3c:

[0078] Step 1: Apply voltage and perform a pulse test on the microwave switch to obtain the shortest pulse time to activate the microwave switch;

[0079] Step 2: Apply the second voltage to the microwave switch for a duration of at least the shortest pulse time.

[0080] Since the microwave switch does not operate continuously, and the thermal power of the microwave switch during normal operation is greater than the cooling power of the MC layer of the dilution refrigerator, a power-on pulse test can be performed after the voltage is set to determine the minimum pulse time that enables the microwave switch to operate, so as to minimize the heat generated by the microwave switch and minimize the impact on the extremely low temperature environment in the dilution refrigerator.

[0081] It is worth noting that the microwave switch in this application is a mechanical switch based on electromagnetic induction. For ease of comparison, in Figure 3The diagram shows a structure of electromagnetic contactors configured based on a control circuit. As shown, an inverted "T" shaped electromagnetic contactor is used, with the number of contactors matching the number of channels. Each channel has one contactor, and channels 1 to 6 have a total of six contactors. Therefore, a relay-type switch can contain multiple electromagnetic contactors, and the number of contactors corresponds one-to-one with the number of second output sub-ports.

[0082] The electromagnetic contactor comprises an iron core, a coil, and a magnetic armature. The coil is wound around the iron core, and its two ends are electrically connected to two adjacent control ports. Magnetic force can control the movement of the magnetic armature to controllably switch the first and second output ports into an on or off state.

[0083] The magnetic armature is assembled with an iron core and a coil. When the coil in this assembly is energized, it generates a magnetic field, which attracts the magnetic armature; when the energizing direction is reversed, it pushes the magnetic armature away. This is how the magnetic armature moves: it rises due to attractive force and falls due to repulsive force.

[0084] In one embodiment of this application, the microwave switch and the superconducting quantum chip are placed together in a dilution refrigerator. The microwave switch is used to realize the rapid switching and on / off of different signal channels required for measurement and control. Based on the above method of reducing the heating of the microwave switch, the heating that has a negative impact on the superconducting quantum computing system is reduced during operation.

[0085] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," or "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0086] The above description, based on the embodiments shown in the drawings, details the structure, features, and effects of this application. The above description is only a preferred embodiment of this application, but this application does not limit the scope of implementation to what is shown in the drawings. Any changes made in accordance with the concept of this application, or modifications to equivalent embodiments, that do not exceed the spirit covered by the specification and drawings, should be within the protection scope of this application.

Claims

1. A method of reducing heat generation in a microwave switch, comprising: The method comprises: determining a first voltage for starting the microwave switch according to a first resistance value of the microwave switch at a first temperature, and determining a corresponding starting threshold current; determining a second voltage for starting the microwave switch based on a second resistance value of the microwave switch at a second temperature, and the starting threshold current; wherein the second temperature is lower than the first temperature; applying the second voltage to the microwave switch at the second temperature, so that the microwave switch is started and the current through the microwave switch is the starting threshold current.

2. The method of reducing heat generation in a microwave switch according to claim 1, wherein, The first temperature is 10-30℃. The second temperature is 10-100mK.

3. The method of claim 1, wherein the microwave switch is a PIN diode. The method for obtaining the first voltage comprises: applying a voltage with an initial value of zero and gradually increasing to the microwave switch at the first temperature; and taking the instantaneous voltage when the microwave switch is turned from a stopped state to a started state in the process as the first voltage.

4. The method of reducing heat generation in a microwave switch of claim 1, wherein, The applying the second voltage to the microwave switch comprises: providing a power supply for the microwave switch, and the voltage of the power supply is not less than the second voltage.

5. The method of reducing heat generation in a microwave switch of claim 4, wherein, The providing the power supply for the microwave switch comprises: using a power supply with an output voltage of the second voltage to supply power to the microwave switch.

6. The method of reducing heat generation in a microwave switch of claim 4, wherein, The providing the power supply for the microwave switch comprises: providing a voltage dividing resistor in series with the microwave switch; using a power supply with an output voltage greater than the second voltage to supply power, so that the voltage applied to the microwave switch by the power supply is the second voltage.

7. The method of reducing heat generation in a microwave switch of claim 6, wherein, The voltage dividing resistor is an adjustable resistor.

8. The method of reducing heat generation in a microwave switch according to claim 5 or 6, wherein, The applying the second voltage to the microwave switch, so that the microwave switch is started and the current through the microwave switch is the starting threshold current comprises: applying a voltage to the microwave switch for pulse testing to obtain the shortest pulse time for starting the microwave switch; applying the second voltage to the microwave switch for a time period of at least the shortest pulse time.

9. The method of reducing heat generation in a microwave switch of claim 1, wherein, The microwave switch is a mechanical switch based on electromagnetic induction.

10. The method for reducing the heat generated by a microwave switch according to claims 1-9, applied in a dilution refrigerator for regulating a superconducting quantum chip.

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