Multi-channel quantum state feedback control method

Abstract

The invention discloses a multichannel quantum state feedback control method. The method comprises the following steps: S1, performing quantum state measurement by using an entanglement collective measurement method; s2, analyzing the state of the obtained quantum state information through a classical calculation method; s3, the processed information is fed back to the quantum system, and the state of the quantum system is adjusted; and S4, the state of the quantum system is monitored in real time, so that feedback control is adjusted in real time. According to the method, entanglement collective measurement is used, non-local measurement is carried out on multiple quantum system copies at the same time, so that the measurement efficiency and precision are improved, and the standard quantum limit is exceeded. According to the method, needed quantum resources can be reduced, weak signals are enhanced, sensitive detection on tiny changes is achieved, damage to the quantum state is reduced, in addition, entanglement collective measurement supports real-time feedback control, the state of a quantum system is allowed to be dynamically adjusted, and performance is optimized. And the problem of precision balance in multi-parameter measurement can be solved, and simultaneous optimal measurement of multiple parameters can be realized.

Description

Technical Field

[0001] The present invention relates to the field of quantum communication, and in particular to a multi-channel quantum state feedback control method. Background Art

[0002] In quantum communication, quantum systems are very sensitive to environmental noise and interference, and are prone to losing their desired quantum states. Quantum systems are also susceptible to various errors, such as quantum bit flip errors. These errors can be detected and corrected through quantum state feedback control. In quantum information processing, feedback control can precisely control these manipulations.

[0003] However, there are great technical difficulties in quantum state feedback control. Among them, quantum measurement usually leads to the collapse of the quantum state, which is a destructive process that will lead to the destruction of the quantum state. In addition, delays in signal processing and feedback control may affect the dynamic response of the system. Especially in high-speed quantum operations, the delay problem is particularly prominent. Summary of the invention

[0004] The present invention aims to provide a multi-channel quantum state feedback control method to solve the above problems.

[0005] The present invention is achieved through the following technical solutions: A multi-channel quantum state feedback control method, comprising: S1: Quantum state measurement using entangled collective measurement methods; S2: Analyze the state of the acquired quantum state information through classical computing methods; S3: Feed the processed information back to the quantum system to adjust its state; S4: Monitor the state of the quantum system in real time, so that feedback control can be adjusted in real time.

[0006] The present invention uses entangled collective measurement, which is an efficient quantum state measurement method that improves measurement efficiency and accuracy by simultaneously performing non-local measurements on multiple copies of a quantum system, surpassing the standard quantum limit. This method can reduce the required quantum resources, enhance weak signals, achieve sensitive detection of small changes, and reduce the destruction of the quantum state. In addition, entangled collective measurement supports real-time feedback control, allowing dynamic adjustment of the state of the quantum system to optimize performance. It also helps to solve the problem of precision checks and balances in multi-parameter measurements and achieve simultaneous optimal measurement of multiple parameters.

[0007] Preferably, the entanglement collective measurement method specifically comprises the following steps: S1.1: Prepare entangled photons and distribute the entangled photons to the communicating parties, i.e., the sender and the receiver; S1.2: The sender and the receiver each have one photon of the entangled photon pair and use a collective measurement device to simultaneously measure the polarization state and orbital angular momentum of the photon; S1.3: Integrate the polarization state information and orbital angular momentum information of the photon to obtain composite quantum state information.

[0008] By measuring the polarization state and orbital angular momentum of photons, the present invention can obtain richer quantum information, which helps to improve the channel capacity and information processing capabilities of quantum communication. The integration of two different quantum state information (polarization and orbital angular momentum) allows quantum information to be encoded and transmitted in a higher-dimensional space, which can improve data transmission rates and information processing efficiency. This method allows more information to be extracted through more effective measurement strategies without adding additional quantum resources, reducing delays in signal processing and feedback control.

[0009] Preferably, the collective measurement device includes a manipulation module, a measurement module and an environmental control module, wherein the manipulation module includes a laser, an electromagnetic field device, a wave plate, and a beam splitter; the measurement module includes a single photon detector, a photomultiplier tube, and a quantum dot detector; and the environmental control module includes a temperature controller, a humidity controller and a pressure controller.

[0010] Preferably, S2 is specifically implemented by the following steps: S2.1: Determine the difference between the current quantum state and the target quantum state; S2.2: Analyze the differences statistically to assess the uncertainty and reliability of the measurements; S2.3: Based on the analysis results of S2.2, the parameters of the generation and measurement process of the quantum state in S1 are adjusted, including the intensity parameter adjustment and phase parameter adjustment of the laser beam.

[0011] Preferably, in S3, S1 receives the parameter adjustment data of S2, uses a quantum convolutional neural network to predict the future state of the quantum state, and adjusts the parameters in advance based on this. The parameters are specifically adjusted by quantum state tomography and quantum parameter estimation to improve the reconstruction process of the quantum state, so as to reduce the number of required measurements and improve the efficiency of the data processing system, and regularly calibrate the measurement results in S1, and after each measurement and adjustment, repeat S1-S2 to iteratively improve the generation and measurement process of the quantum state.

[0012] Preferably, the activation function of the quantum convolutional neural network is: in is a quantum state; is the number of quantum bits; is a classical data bit, and ; Preferably, the loss function of the quantum convolutional neural network is: where MSE is the average of the sum of squared prediction errors of these qubits; represents the true value of the i-th quantum bit, which is the measurement value obtained by S1; represents the model's predicted value for the i-th quantum bit; is the number of quantum bits.

[0013] The MSE of the present invention directly reflects the average size of the difference between the predicted value and the true value. The smaller the value, the more accurate the prediction of the model is, which is easy to understand and explain. In addition, MSE is a smooth function with a continuous gradient, which makes it possible to effectively update the model parameters through optimization algorithms such as gradient descent. Moreover, MSE imposes a greater penalty on larger errors, which helps the model pay more attention to reducing large prediction errors during training.

[0014] Preferably, S1 is a weak measurement method for quantum state measurement, which specifically introduces a photon probe to interact weakly with the quantum system, and after the measurement, the final state of the system is selected according to the state of the probe.

[0015] Preferably, it also includes S5: stability and robustness analysis, which specifically includes quantum noise source analysis and decoherence influence analysis.

[0016] Preferably, the quantum channel of photons is an optical fiber and a quantum storage device.

[0017] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. The present invention uses entangled collective measurement, which is an efficient quantum state measurement method that improves measurement efficiency and accuracy by performing non-local measurements on multiple copies of a quantum system simultaneously, surpassing the standard quantum limit. This method can reduce the required quantum resources, enhance weak signals, and achieve sensitive detection of small changes, making it very suitable for quantum precision measurement and quantum sensing applications. In addition, entangled collective measurement supports real-time feedback control, allowing dynamic adjustment of the state of the quantum system to optimize performance. It also helps to solve the problem of precision checks and balances in multi-parameter measurements and achieve simultaneous optimal measurement of multiple parameters. In quantum information processing and basic research in quantum mechanics, entangled collective measurement provides a new way to improve the security and efficiency of quantum communications, and demonstrates its application potential in multiple fields such as quantum computing, quantum communication, and quantum precision measurement.

[0018] 2. The present invention can obtain richer quantum information by measuring the polarization state and orbital angular momentum of photons, which helps to improve the channel capacity and information processing capabilities of quantum communication. The integration of two different quantum state information (polarization and orbital angular momentum) allows quantum information to be encoded and transmitted in a higher-dimensional space, which can improve the data transmission rate and information processing efficiency. This method allows more information to be extracted through more effective measurement strategies without adding additional quantum resources, reducing the delay of signal processing and feedback control.

[0019] 3. The MSE of the present invention directly reflects the average size of the difference between the predicted value and the true value. The smaller the value, the more accurate the prediction of the model, which is easy to understand and explain. In addition, MSE is a smooth function with a continuous gradient, which makes it possible to effectively update the model parameters through optimization algorithms such as gradient descent. Moreover, MSE imposes a greater penalty on larger errors, which helps the model pay more attention to reducing large prediction errors during training. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is further described in detail below, but the protection scope of the present invention is not limited to the following.

[0021] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the embodiments described are only part of the embodiments of the present invention, rather than all the embodiments.

[0022] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present invention. It should be noted that relational terms such as the terms "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0023] Moreover, the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a list of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus. In the absence of more restrictions, an element defined by the phrase "comprises a ..." does not exclude the presence of additional identical elements in the process, method, article or apparatus that includes the element.

[0024] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0025] Example A multi-channel quantum state feedback control method, comprising: S1: Quantum state measurement using entangled collective measurement methods; S2: Analyze the state of the acquired quantum state information through classical computing methods; S3: Feed the processed information back to the quantum system to adjust its state; S4: Monitor the state of the quantum system in real time, so that feedback control can be adjusted in real time.

[0026] The present invention uses entangled collective measurement, which is an efficient quantum state measurement method that improves measurement efficiency and accuracy by simultaneously performing non-local measurements on multiple copies of a quantum system, surpassing the standard quantum limit. This method can reduce the required quantum resources, enhance weak signals, achieve sensitive detection of small changes, and reduce the destruction of the quantum state. In addition, entangled collective measurement supports real-time feedback control, allowing dynamic adjustment of the state of the quantum system to optimize performance. It also helps to solve the problem of precision checks and balances in multi-parameter measurements and achieve simultaneous optimal measurement of multiple parameters.

[0027] In this embodiment, S3 specifically includes the following steps: S3.1 Error diagnosis, compare the measurement information obtained in S2 with the input information to determine whether there is an error in the system and the type of error; S3.2 error correction, based on the diagnosis result of S3.1, performing corresponding error correction operations, including phase flipping, flipping and other operations, to restore the quantum state; In this embodiment, S4 specifically includes the following steps: S4.1: System status update. After diagnosis and correction in S3, the system status will change. At this time, it is necessary to re-estimate the state of the quantum system and perform error diagnosis and correction again based on the new state information. S4.2: Iterative loop, real-time monitoring and feedback control is a dynamic cyclic process that involves continuous state estimation, error diagnosis, and error correction until the quantum system reaches or remains in the desired state.

[0028] In this embodiment, the entanglement collective measurement method specifically includes the following steps: S1.1: Prepare entangled photons and distribute the entangled photons to the communicating parties, i.e., the sender and the receiver; S1.2: The sender and the receiver each have one photon of the entangled photon pair and use a collective measurement device to simultaneously measure the polarization state and orbital angular momentum of the photon; S1.3: Integrate the polarization state information and orbital angular momentum information of the photon to obtain composite quantum state information.

[0029] By measuring the polarization state and orbital angular momentum of photons, the present invention can obtain richer quantum information, which helps to improve the channel capacity and information processing capabilities of quantum communication. The integration of two different quantum state information (polarization and orbital angular momentum) allows quantum information to be encoded and transmitted in a higher-dimensional space, which can improve data transmission rates and information processing efficiency. This method allows more information to be extracted through more effective measurement strategies without adding additional quantum resources, reducing delays in signal processing and feedback control.

[0030] In this embodiment, the collective measurement device includes a control module, a measurement module and an environmental control module, wherein the control module includes a laser, an electromagnetic field device, a wave plate, and a beam splitter; the measurement module includes a single photon detector, a photomultiplier tube, and a quantum dot detector; and the environmental control module includes a temperature controller, a humidity controller and a pressure controller.

[0031] In this embodiment, S2 is specifically implemented by the following steps: S2.1: Determine the difference between the current quantum state and the target quantum state; S2.2: Analyze the differences statistically to assess the uncertainty and reliability of the measurements; S2.3: Based on the analysis results of S2.2, the parameters of the generation and measurement process of the quantum state in S1 are adjusted, including the intensity parameter adjustment and phase parameter adjustment of the laser beam.

[0032] In this embodiment, in S3, S1 receives the parameter adjustment data of S2, uses the quantum convolutional neural network to predict the future state of the quantum state, and adjusts the parameters in advance based on this. The parameters are specifically adjusted by quantum state tomography and quantum parameter estimation to improve the reconstruction process of the quantum state, so as to reduce the number of required measurements and improve the efficiency of the data processing system, and regularly calibrate the measurement results in S1, and after each measurement and adjustment, repeat S1-S2 to iteratively improve the generation and measurement process of the quantum state.

[0033] In this embodiment, the activation function of the quantum convolutional neural network is: in is a quantum state; is the number of quantum bits; is a classical data bit, and ; In this embodiment, the loss function of the quantum convolutional neural network is: where MSE is the average of the sum of squared prediction errors of these qubits; represents the true value of the i-th quantum bit, which is the measurement value obtained by S1; represents the model's predicted value for the i-th quantum bit; is the number of quantum bits.

[0034] The MSE of the present invention directly reflects the average size of the difference between the predicted value and the true value. The smaller the value, the more accurate the prediction of the model is, which is easy to understand and explain. In addition, MSE is a smooth function with a continuous gradient, which makes it possible to effectively update the model parameters through optimization algorithms such as gradient descent. Moreover, MSE imposes a greater penalty on larger errors, which helps the model pay more attention to reducing large prediction errors during training.

[0035] In this embodiment, S1 is a weak measurement method for quantum state measurement, which specifically introduces a photon probe to interact weakly with the quantum system. After the measurement, the final state of the system is selected according to the state of the probe.

[0036] In this embodiment, S5: stability and robustness analysis is also included, which specifically includes quantum noise source analysis and decoherence influence analysis.

[0037] In this embodiment, S5 specifically includes the following steps: S5.1: Analysis of quantum noise sources: Quantum noise includes ambient temperature, electromagnetic fluctuations, material defects, preparation and manipulation of quantum systems, etc. Environmental noise may cause frequency disturbances of quantum bits through interaction with quantum systems, thereby causing phase decoherence.

[0038] S5.2: Analysis of decoherence effects: Decoherence refers to the loss of quantum coherence caused by the interaction between a quantum system and its environment. It can be described by the non-unitary evolution of the quantum state, usually involving the diagonalization of the density matrix. Quantum decoherence involves considering the dynamical model of the quantum system, analyzing the evolution of the quantum state over time, and studying how to reduce the effects of decoherence through control measures.

[0039] S5.3: Stability analysis: Stability analysis uses the dynamical equations of the quantum system, specifically the Lindblad master equation, to analyze the evolution of the quantum system and design a control strategy to suppress the effects of noise and maintain the stability of the quantum state.

[0040] S5.4: Robust design: Robust design aims to ensure that quantum systems maintain their performance in the face of uncertainty and interference, by encoding quantum systems, using quantum error correction codes to protect quantum information, and designing robust quantum control strategies to combat the effects of noise and decoherence.

[0041] In this embodiment, the quantum channel of photons is an optical fiber and a quantum storage device.

[0042] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A multi-channel quantum state feedback control method, characterized in that: include: S1: Quantum state measurement using entangled collective measurement methods; S2: Analyze the state of the acquired quantum state information through classical computing methods; S3: Feed the processed information back to the quantum system to adjust its state; S4: Monitor the state of the quantum system in real time, so that feedback control can be adjusted in real time.

2. A multi-channel quantum state feedback control method according to claim 1, characterized in that: The entanglement collective measurement method specifically includes the following steps: S1.1: Prepare entangled photons and distribute the entangled photons to the communicating parties, i.e., the sender and the receiver; S1.2: The sender and the receiver each have one photon of the entangled photon pair and use a collective measurement device to simultaneously measure the polarization state and orbital angular momentum of the photon; S1.3: Integrate the polarization state information and orbital angular momentum information of the photon to obtain composite quantum state information.

3. A multi-channel quantum state feedback control method according to claim 2, characterized in that: The collective measurement equipment includes a control module, a measurement module and an environmental control module, wherein the control module includes a laser, an electromagnetic field device, a wave plate, and a beam splitter; the measurement module includes a single photon detector, a photomultiplier tube, and a quantum dot detector; and the environmental control module includes a temperature controller, a humidity controller and a pressure controller.

4. A multi-channel quantum state feedback control method according to claim 3, characterized in that: S2 is implemented through the following steps: S2.1: Determine the difference between the current quantum state and the target quantum state; S2.2: Analyze the differences statistically to assess the uncertainty and reliability of the measurements; S2.3: Based on the analysis results of S2.2, the parameters of the generation and measurement process of the quantum state in S1 are adjusted, including the intensity parameter adjustment and phase parameter adjustment of the laser beam.

5. A multi-channel quantum state feedback control method according to claim 4, characterized in that: In S3, S1 receives the parameter adjustment data from S2, uses the quantum convolutional neural network to predict the future state of the quantum state, and adjusts the parameters in advance based on this. The parameters are specifically adjusted by improving the reconstruction process of the quantum state through quantum state tomography and quantum parameter estimation to reduce the number of required measurements and improve the efficiency of the data processing system. The measurement results in S1 are calibrated regularly, and after each measurement and adjustment, S1-S2 is repeated to iteratively improve the generation and measurement process of the quantum state.

6. A multi-channel quantum state feedback control method according to claim 5, characterized in that: The activation function of the quantum convolutional neural network is: in is a quantum state; is the number of quantum bits; is a classical data bit, and .

7. A multi-channel quantum state feedback control method according to claim 6, characterized in that: The loss function of the quantum convolutional neural network is: where MSE is the average of the sum of squared prediction errors of these qubits; represents the true value of the i-th quantum bit, which is the measurement value obtained by S1; represents the model's predicted value for the i-th quantum bit; is the number of quantum bits.

8. A multi-channel quantum state feedback control method according to claim 7, characterized in that: S1 is a weak measurement method for quantum state measurement, which specifically introduces a photon probe to interact weakly with the quantum system. After the measurement, the final state of the system is selected according to the state of the probe.

9. A multi-channel quantum state feedback control method according to claim 8, characterized in that: It also includes S5: Stability and robustness analysis, which specifically includes analysis of quantum noise sources and analysis of decoherence effects.

10. A multi-channel quantum state feedback control method according to claim 9, characterized in that: The quantum channels of photons are optical fibers and quantum storage devices.

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