Quantum measurement and control signal feedback apparatus and method based on weak magnetic detection
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2026-01-16
- Publication Date
- 2026-08-13
Smart Images
Figure CN2026073116_13082026_PF_FP_ABST
Abstract
Description
A quantum measurement and control signal feedback device and method based on weak magnetic field detection Technical Field
[0001] This invention relates to the field of quantum information technology, specifically to a quantum measurement and control signal feedback device and method based on weak magnetic field detection. Background Technology
[0002] With the rapid development of quantum information technology, quantum chips and qubit control technology have become hot topics in the research field. As the core component of quantum information processing, quantum chips typically need to operate in extremely low-temperature environments to ensure high-precision control signals and feedback control. Traditional quantum chip control methods mainly rely on reading the logic state of the qubits to achieve feedback control, but this approach has shortcomings in real-time performance and anti-interference capabilities, potentially causing delays and instabilities in feedback control, thus affecting the overall performance of the quantum chip.
[0003] To overcome these challenges, researchers have begun using superconducting quantum interference devices (SQUIDs) for feedback control of weak magnetic field detection. As a highly sensitive magnetic field detector, the SQUID can operate reliably in extremely low-temperature environments and sense weak stray magnetic fields generated by qubit control signals. However, despite the theoretical advantages of SQUID-based weak magnetic field detection methods, a series of technical challenges remain to be overcome in practical applications. For example, patent CN114037085A describes a quantum manipulation feedback system and method, which requires characterization of quantum states and suffers from insufficient real-time performance, susceptibility to interference, and inability to detect signal crosstalk.
[0004] Therefore, how to address the shortcomings and deficiencies of existing technologies through effective quantum measurement and control signal feedback methods has become an important issue that researchers in this field urgently need to solve. Summary of the Invention
[0005] The purpose of this invention is to address the above-mentioned problems by providing a quantum measurement and control signal feedback device and method based on weak magnetic field detection.
[0006] The technical solution of this invention is as follows: a quantum chip, the quantum chip including an input end and an output end, and a plurality of signal transmission lines connected between the input end and the output end, the signal transmission lines including a first signal node, and a quantum bit connected between the first signal node and the output end, the input end being used to receive a control signal; a control signal generation module, used to generate a first control signal controlling the quantum bits in the quantum chip, the first control signal being transmitted in the plurality of signal transmission lines and generating a stray magnetic field; a superconducting quantum interference detector, used to detect a weak magnetic signal generated by the stray magnetic field at the first signal node; a main control module, used to compare the first control signal and the weak magnetic signal and generate a feedback control signal, the feedback control signal being used to adjust the weak magnetic signal to be consistent with the first control signal.
[0007] As an improvement to this embodiment of the invention, the superconducting quantum interference device detector is provided with a probe, the projected area of which is less than 0.1 mm². 2 The distance between the probe and the quantum chip is N, 0.1 mm. <N<5mm。
[0008] As an improvement to this embodiment of the invention, the probe is positioned at a distance N = 1 mm from the quantum chip.
[0009] As an improvement of this embodiment of the invention, the feedback control signal is inverted to the difference between the first control signal and the magnetic weakening signal, and is transmitted to the first signal node through the feedback loop to compensate for the fluctuation of the first control signal, so that the magnetic weakening signal is consistent with the first control signal.
[0010] As an improvement of this invention, the quantum chip includes several quantum gates for performing logical operations or quantum operations on qubits. The quantum gates operate based on the logical state of the qubits to realize the processing and transformation of quantum information.
[0011] As an improvement of this embodiment of the invention, the main control module further includes a signal amplification unit, which is used to amplify the weak magnetic signal detected by the superconducting quantum interference detector.
[0012] As an improvement of this embodiment of the invention, the main control module further includes a signal filtering unit, which is used to filter the weak magnetic signal detected by the superconducting quantum interference detector.
[0013] As an improvement of this embodiment of the invention, the main control module further includes a comparator, which is used to compare the difference between the magnetic weakening signal and the first control signal.
[0014] To achieve one of the above-mentioned objectives, one embodiment of the present invention provides a quantum measurement and control signal feedback method based on weak magnetic field detection. The quantum measurement and control signal feedback method is applied to the quantum measurement and control signal feedback device as described in any of the preceding claims, and includes the following steps: generating a first control signal for controlling qubits in a quantum chip through the control signal generation module and transmitting it to the input terminal of the quantum chip; transmitting the first control signal in several signal transmission lines and generating a stray magnetic field; detecting a weak magnetic signal generated by the stray magnetic field at the first signal node through the superconducting quantum interference device detector; comparing the weak magnetic signal with the first control signal and generating a feedback control signal, the feedback control signal being used to adjust the weak magnetic signal to be consistent with the first control signal.
[0015] As an improvement to an embodiment of the present invention, the method further includes the following steps: measuring the signal crosstalk between the qubits using a probe disposed in the detector of the superconducting quantum interference device and feeding it back to the main control module.
[0016] The quantum measurement and control signal feedback method and device based on weak magnetic field detection provided in this invention have the following advantages: This invention achieves real-time feedback control by monitoring the stray magnetic field generated by the quantum bit control signal in real time through a superconducting quantum interference device. It does not require direct reading of the quantum bit state, thus minimizing interference to the operation of the quantum chip and significantly improving the control accuracy and stability of the quantum chip. At the same time, it can detect signal crosstalk between quantum bits. Attached Figure Description
[0017] Figure 1 is a schematic diagram of the position of the quantum chip and the superconducting quantum interference device detector described in this invention;
[0018] Figure 2 is a flowchart illustrating the quantum measurement and control signal feedback method based on weak magnetic field detection described in this invention. Detailed Implementation
[0019] The present invention will now be described in detail with reference to the specific embodiments shown in the accompanying drawings. However, these embodiments do not limit the present invention, and any structural, methodological, or functional modifications made by those skilled in the art based on these embodiments are included within the scope of protection of the present invention.
[0020] If the present invention involves orientation (e.g., up, down, left, right, front, back, outside, inside, etc.) in its description, then the orientations involved need to be defined.
[0021] The scope of the embodiments described herein includes the entire scope of the claims and all available equivalents thereof. Throughout this document, the terms “first,” “second,” etc., are used only to distinguish one element from another without requiring or implying any actual relationship or order between the elements. Indeed, a first element can also be referred to as a second element, and vice versa. Furthermore, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a structure, apparatus, or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a structure, apparatus, or device. Without further limitations, an element defined by the phrase “comprising one…” does not exclude the presence of other identical elements in the structure, apparatus, or device that includes said element. The various embodiments described herein are presented in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably.
[0022] The terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer" used in this document to indicate orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings and are used only for the convenience of describing this document and simplifying the description. They 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, and therefore should not be construed as limiting the invention. In the description herein, unless otherwise specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two elements, or direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.
[0023] Embodiment 1 of the present invention provides a quantum measurement and control signal feedback device based on weak magnetic field detection, comprising:
[0024] As shown in Figure 1, the quantum chip 1 includes an input terminal 11 and an output terminal 12, as well as several signal transmission lines 13 connected between the input terminal 11 and the output terminal 12. Each signal transmission line 13 includes a first signal node 14, and a qubit 15 is connected between the first signal node 14 and the output terminal 12. The input terminal 11 is used to receive control signals. In practice, the quantum chip is a core component in the field of quantum information technology. Its basic unit is the qubit, whose logical state can be 0, 1, or a superposition of 0 and 1. The state of the qubit can be manipulated by external control signals.
[0025] A control signal generation module is used to generate a first control signal for controlling the qubits 15 in the quantum chip 1. The first control signal is transmitted in the plurality of signal transmission lines 13 and generates a stray magnetic field. In practice, the first control signal can be an electrical signal or a microwave signal, etc. When the qubit 15 receives the first control signal, its logic state changes.
[0026] A superconducting quantum interference device (SQU) detector 2 is used to detect the weak magnetic signal generated by the stray magnetic field at the first signal node 14. Here, the SQU detector 2 is a highly sensitive magnetic field detector capable of detecting weak magnetic field changes in extremely low-temperature environments. The SQU detector 2 described in this invention is used to detect the stray magnetic field at the first signal node 14 and converts the detected weak magnetic signal into an electrical signal output.
[0027] The main control module is used to compare the first control signal and the magnetic weakening signal and generate a feedback control signal, which is used to adjust the magnetic weakening signal to be consistent with the first control signal.
[0028] Before starting the device, initialization is required, including setting the operating parameters of quantum chip 1, calibrating the sensitivity of superconducting quantum interference detector 2, and configuring the control logic of the main control module. The control signal generation module generates a first control signal according to a preset algorithm or instruction and transmits it to quantum chip 1 to manipulate the state of qubits 15. The first control signal is transmitted through several signal transmission lines 13 and generates a stray magnetic field. Superconducting quantum interference detector 2 senses the magnetic field signal and converts it into an electrical signal, which is then output to the main control module. The main control module receives the first control signal and the weak magnetic signal output by superconducting quantum interference detector 2, and compares and analyzes the two signals. If there is a difference between the first control signal and the weak magnetic signal, the main control module generates a corresponding feedback control signal and adjusts the fluctuation of the first control signal based on the feedback control signal, thereby improving the accuracy of quantum chip 1 control. Simultaneously, the main control module can also detect signal crosstalk between qubits 15 on quantum chip 1 in real time and adjust the position and size of probes 21 in superconducting quantum interference detector 2 according to the detection results to optimize the detection effect.
[0029] In this embodiment, the superconducting quantum interference device detector 2 is equipped with a probe 21, the projected area of which is less than 0.1 mm². 2, the distance between the probe 21 and the quantum chip 1 is N, where 0.1 mm < N < 5 mm. Preferably, N = 1 mm. It can be understood that setting N to 1 mm can maintain an appropriate interval between the probe 21 and the quantum chip 1, reduce the physical contact between the probe 21 and the quantum chip 1, thereby reducing the noise and interference generated by the contact, and can also ensure that the superconducting quantum interference detector 2 can capture the magnetic field signal, improving the accuracy and reliability of the measurement.
[0030] In this embodiment, the feedback control signal inverts the difference between the first control signal and the weak magnetic signal, and is conducted through the feedback loop to the first signal node 14 to compensate for the fluctuation of the first control signal, making the weak magnetic signal consistent with the first control signal.
[0031] Here, a feedback loop connecting the main control module and the quantum chip 1 is also provided on the main control module. The feedback loop is used to conduct the feedback control signal to the first signal node 14. In practice, the state of the qubit 15 in the quantum chip 1 needs to be regulated by a control signal. However, due to factors such as environmental noise and system instability, the directly applied first control signal often has fluctuations, which will affect the stability and accuracy of the state of the qubit 15. The feedback control signal is generated based on the difference between the first control signal and the weak magnetic signal detected by the superconducting quantum interference detector 2 at the first signal node 14. This difference reflects the deviation of the first control signal relative to the weak magnetic signal. To eliminate this deviation, a feedback control signal that is opposite in phase to the difference is generated. The role of the feedback control signal is to fine-tune the weak magnetic signal through the feedback loop to compensate for the fluctuation of the first control signal. It can be understood that this achieves precise control of the state of the qubit 15 and high-stability operation of the quantum chip 1.
[0032] In this embodiment, the quantum chip 1 includes a plurality of quantum gates for performing logical operations or quantum operations on the qubit 15. The quantum gates operate based on the logical state of the qubit 15 to achieve the processing and transformation of quantum information.
[0033] In practice, the quantum gate can be a single qubit 15 gate, such as a Hadamard gate, a Pauli-X gate (NOT gate), a phase gate, etc.; a two-qubit 15 gate: such as a controlled-NOT gate (CNOT gate), a controlled-Z gate, etc.; a multi-qubit 15 gate: such as a Toffoli gate, a Fredkin gate, etc. It can be understood that the quantum gates operate based on the logical state of the qubit 15 and play a crucial role in quantum information processing.
[0034] In this embodiment, the main control module further includes a signal amplification unit, which is used to amplify the weak magnetic signal detected by the superconducting quantum interference detector 2.
[0035] Here, the main task of the signal amplification unit is to amplify the weak electrical signal output by the superconducting quantum interference device (SQU) detector 2, so that subsequent signal processing can be performed accurately and effectively. To reduce noise interference during amplification, the signal amplification unit can employ a low-noise amplifier to minimize its own noise while amplifying the signal. Since the SQU detector 2 may generate signals of different amplitudes in different application scenarios, the signal amplification unit described in this embodiment has an adjustable gain function, allowing users to adjust the amplification factor according to actual needs to achieve optimal signal quality. To maintain signal integrity, the signal amplification unit also has high linearity, meaning that the input signal and the second signal should maintain a good linear relationship. This helps reduce distortion and avoid errors caused by nonlinear effects. Furthermore, to reduce the impact of electromagnetic interference and radio frequency interference, the signal amplification unit and its surrounding circuitry employ shielding measures to ensure signal purity. By integrating the signal amplification unit, the main control module effectively solves the problem of weak second signals from the SQU detector 2, improving the sensitivity and accuracy of the entire system.
[0036] In this embodiment, the main control module further includes a signal filtering unit, which is used to filter the weak magnetic signal detected by the superconducting quantum interference detector 2.
[0037] In practice, the signals received by the main control module are often accompanied by various noises and interferences, and direct processing may lead to signal inaccuracies. Therefore, in this embodiment, the main control module introduces a signal filtering unit to filter the received first control signal and the magnetic weakening signal, thereby improving the signal-to-noise ratio and overall quality. Depending on the application requirements and signal characteristics, the signal filtering unit can employ different types of filters, such as low-pass filters, high-pass filters, band-pass filters, or band-stop filters. Different filters can remove noise above or below specific frequencies, or only allow signals within a specific frequency range to pass. To improve the adaptability and flexibility of the filter, the signal filtering unit can also employ adaptive filtering technology. This means that adaptive filtering technology can automatically adjust the filter parameters according to changes in the input signal, thereby effectively suppressing different types of noise. To verify the effectiveness of the filtering unit, the quality of the signals before and after filtering needs to be evaluated. The degree of improvement in signal quality by the filtering unit can be objectively reflected by calculating indicators such as signal-to-noise ratio, mean square error, and peak signal-to-noise ratio.
[0038] In this embodiment, the main control module further includes a comparator, which is used to compare the difference between the magnetic weakening signal and the first control signal.
[0039] Here, the comparator integrates a high-precision difference calculation circuit, which can calculate the difference between the magnetic weakening signal and the first control signal in real time. The calculated difference can be used to determine whether there is a deviation in the magnetic weakening signal, and thus appropriate correction measures can be taken. It can be understood that the main control module in this embodiment, by integrating a comparator, realizes the function of comparing the difference between the magnetic weakening signal and the first control signal, effectively improving the accuracy of signal feedback.
[0040] Embodiment 2 of the present invention provides a quantum measurement and control signal feedback method based on weak magnetic field detection. The quantum measurement and control signal feedback method is applied to the quantum measurement and control signal feedback device described in any of the above embodiments, as shown in Figure 2, and includes the following steps:
[0041] Step 101: The control signal generation module generates a first control signal for controlling the qubits 15 in the quantum chip 1 and transmits it to the input terminal 11 of the quantum chip 1.
[0042] Step 102: The first control signal is transmitted in the plurality of signal transmission lines and generates a stray magnetic field;
[0043] Step 103: Detect the weak magnetic signal generated by the stray magnetic field at the first signal node 14 using the superconducting quantum interference device;
[0044] Step 104: The main control module compares the magnetic weakening signal with the first control signal and generates a feedback control signal, which is used to adjust the magnetic weakening signal to be consistent with the first control signal.
[0045] In this embodiment, the following steps are also included: measuring the signal crosstalk between the qubits 15 by means of the probe 21 set in the superconducting quantum interference detector 2 and feeding it back to the main control module.
[0046] Here, in quantum chip 1, due to the close spatial distance between qubits 15, their state changes may affect each other, leading to signal crosstalk and thus interfering with the control of qubits 15. Therefore, this embodiment introduces a signal crosstalk measurement step based on the original feedback control method. The probe 21 is set in the superconducting quantum interference detector 2 to measure the signal crosstalk between qubits 15. The probe 21 can be a highly sensitive magnetic field sensor. When measuring the signal crosstalk between qubits 15, the distance between the probe 21 and the quantum chip 1 is 0.1 mm, which can capture the interference between qubits 15. The main control module receives not only the weak magnetic signal from the superconducting quantum interference detector 2, but also the signal crosstalk information from the probe 21. Based on this information, the main control module can more accurately evaluate the state of qubits 15. It can be understood that this embodiment further improves the accuracy and reliability of the quantum measurement and control signal feedback method by introducing a signal crosstalk measurement step.
[0047] It should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
[0048] The detailed descriptions listed above are merely specific descriptions of feasible embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.
Claims
1. A quantum measurement and control signal feedback device based on weak magnetic field detection, characterized in that, include: A quantum chip (1) includes an input terminal (11) and an output terminal (12), and a plurality of signal transmission lines (13) connected between the input terminal and the output terminal. The signal transmission lines (13) include a first signal node (14), and a quantum bit (15) is connected between the first signal node (14) and the output terminal (12). The input terminal (11) is used to receive control signals. A control signal generation module is used to generate a first control signal for controlling the qubits in the quantum chip. The first control signal is transmitted in the plurality of signal transmission lines and generates a stray magnetic field. A superconducting quantum interference detector (2) is used to detect the weak magnetic signal generated by the stray magnetic field at the first signal node (14); The main control module is used to compare the first control signal and the magnetic weakening signal and generate a feedback control signal, which is used to adjust the magnetic weakening signal to be consistent with the first control signal.
2. The feedback device according to claim 1, characterized in that, The superconducting quantum interference detector (2) is equipped with a probe (21), the projected area of which is less than 0.1 mm. 2 The distance between the probe and the quantum chip is N, 0.1 mm. <N<5mm。 3. The feedback device according to claim 2, characterized in that, The probe is at a distance of N = 1 mm from the quantum chip.
4. The feedback device according to claim 1, characterized in that, The feedback control signal is inverted by the difference between the first control signal and the magnetic weakening signal, and is transmitted to the first signal node (14) through the feedback loop to compensate for the fluctuation of the first control signal, so that the magnetic weakening signal is consistent with the first control signal.
5. The feedback device according to claim 1, characterized in that, The quantum chip includes several quantum gates for performing logical operations or quantum operations on qubits. The quantum gates operate based on the logical state of the qubits to realize the processing and transformation of quantum information.
6. The feedback device according to claim 1, characterized in that, The main control module also includes a signal amplification unit, which is used to amplify the weak magnetic signal detected by the superconducting quantum interference detector.
7. The feedback device according to claim 1, characterized in that, The main control module also includes a signal filtering unit, which is used to filter the weak magnetic signal detected by the superconducting quantum interference detector.
8. The feedback device according to claim 1, characterized in that, The main control module also includes a comparator, which is used to compare the difference between the magnetic weakening signal and the first control signal.
9. A quantum measurement and control signal feedback method based on weak magnetic field detection, characterized in that, The quantum measurement and control signal feedback method, applied to the quantum measurement and control signal feedback device as described in any one of claims 1 to 8, includes the following steps: The control signal generation module generates a first control signal for controlling the qubits in the quantum chip (1) and transmits it to the input terminal (11) of the quantum chip. The first control signal is transmitted in the plurality of signal transmission lines (13) and generates a stray magnetic field; The weak magnetic signal generated by the stray magnetic field at the first signal node (14) is detected by the superconducting quantum interference detector (2); The main control module compares the magnetic weakening signal with the first control signal and generates a feedback control signal, which is used to adjust the magnetic weakening signal to be consistent with the first control signal.
10. The quantum measurement and control signal feedback method according to claim 9, characterized in that, It also includes the following steps: The signal crosstalk between the qubits (15) is measured by the probe (21) set in the superconducting quantum interference detector (2) and fed back to the main control module.