Multi-signal detection device and method based on quantum entanglement and joint measurement

Abstract

The application discloses a multi-signal detection device based on quantum entanglement and joint measurement, comprising a laser, an optical parametric amplifier group, a signal loading module group, a beam splitter network group and a balanced homodyne detection device group arranged in sequence along an optical path. The device adopts a modular optical structure design, and through the synergistic effect of compressed light source, entangled state preparation, interference measurement and joint detection, realizes the function of quantum enhanced measurement. The application also discloses a method for multi-signal detection by using the device, and through the introduction of quantum entanglement resources and the combination of joint measurement mechanism, the sensitivity of multi-parameter measurement is significantly improved. The measurement precision of multiple parameters to be estimated can all break through the standard quantum limit, and reach the quantum Cramer-Rao bound of the system; meanwhile, the estimation precision of each parameter presents good consistency.

Description

Technical Field

[0001] This invention belongs to the field of quantum precision measurement technology, and relates to a multi-signal detection device based on quantum entanglement and joint measurement. This invention also relates to a method for multi-signal detection using the above-mentioned multi-signal detection device. Background Technology

[0002] With the development of precision measurement technology, the demand for high-sensitivity detection of weak signals is becoming increasingly prominent in fields such as gravitational wave detection, precision imaging, inertial navigation, and weak phase measurement. Traditional optical interferometry methods (such as the Mach–Zehnder interferometer) typically use classical light fields as input and obtain the physical parameters to be measured by measuring changes in the output light intensity. Their measurement accuracy is limited by shot noise, the so-called Shot Noise Limit (SNL). To overcome the shot noise limit, researchers have proposed using non-classical light fields (such as squeezed states and entangled states) for quantum-enhanced measurements. Quantum resource-based measurement schemes can improve the signal-to-noise ratio under certain conditions, thus achieving measurement accuracy superior to classical methods. However, most current research focuses on single-parameter estimation problems; for simultaneous estimation of multiple parameters, the measurement performance is still constrained by various factors.

[0003] In existing multi-parameter quantum measurement systems, statistical coupling between parameters is inevitable because different parameters to be estimated typically act on different channels. Traditional multi-parameter measurement methods usually employ a strategy of independent measurement of each parameter, i.e., probing each parameter separately. This method increases system complexity and makes it difficult to fully utilize the quantum correlation resources existing in multi-mode systems, thus limiting further improvements in overall measurement accuracy. On the other hand, quantum entanglement, as an important quantum resource, can establish strong correlation structures between multiple modes in a multi-mode system, providing the possibility for the collaborative extraction of multi-parameter information. However, current technologies lack effective synergy between multi-mode entanglement resources and measurement strategies, especially lacking measurement devices and implementation schemes that can combine joint measurement methods to fully exploit the parameter correlation information in multi-mode entangled states.

[0004] Therefore, designing a highly sensitive multi-parameter detection device and measurement method that can effectively combine multi-mode entanglement resources with joint measurement strategies, thereby reducing system complexity while improving the overall accuracy of multi-parameter measurement and enhancing measurement performance to approach the quantum Cramer-Rao boundary, has become a key technical problem that urgently needs to be solved in the field of multi-parameter quantum precision measurement. Summary of the Invention

[0005] The purpose of this invention is to provide a multi-signal detection device based on quantum entanglement and joint measurement, which can achieve an overall improvement in the accuracy of multi-parameter measurement.

[0006] The second objective of this invention is to provide a method for multi-signal detection using the aforementioned multi-signal detection device, thereby solving the technical problem in existing multi-parameter measurement methods where the measurement sensitivity of distributed nodes is limited by shot noise limits due to the use of classical coherent light or low-order entangled sources, and where noise crosstalk exists between the measurements of each parameter, making it difficult to simultaneously achieve the highest measurement accuracy.

[0007] The technical solution adopted in this invention is a multi-signal detection device based on quantum entanglement and joint measurement, comprising a laser, an optical parametric amplifier group, a signal loading module group, a beam splitter network group, and a balanced zero-beat detection device group arranged sequentially along the optical path; The optical parametric amplifier group includes a first optical parametric amplifier, a second optical parametric amplifier, and a third optical parametric amplifier arranged in parallel along a direction perpendicular to the optical path; the beam splitter network group includes a first beam splitter and a second beam splitter; the signal loading module group includes no less than two signal loading modules; and the balanced zero-beat detection device group includes three balanced zero-beat detection devices. The first optical parametric amplifier is used to generate an orthogonal phase-compressed optical field, and the second and third optical parametric amplifiers are both used to generate orthogonal amplitude-compressed optical fields. The first and second beam splitters are used to couple the compressed optical fields generated by the first, second, and third optical parametric amplifiers. The signal loading module is used to introduce multiple weak signals to be measured into the optical field. The balanced zero-beat detection device is used to extract the orthogonal amplitude and orthogonal phase components of the optical field.

[0008] The invention is further characterized by: The first beam splitter has a transmission-to-reflection ratio of 1:2, and the second beam splitter has a transmission-to-reflection ratio of 1:1. The first and second beam splitters are respectively locked to... and Phase.

[0009] The laser is a single-frequency Nd:YAP / LBO all-solid-state laser with tunable internal cavity frequency doubling; the first, second, and third optical parametric amplifiers are all composed of a nonlinear crystal and two concave mirrors.

[0010] The second technical solution adopted in this invention is a multi-signal detection method based on quantum entanglement and joint measurement, and the specific detection steps are as follows: Step 1: Input the three coherent light fields generated by the laser into the optical parametric amplifier group respectively. The optical parametric amplifier group outputs three compressed light fields. The three compressed light fields are interferometrically coupled through the beam splitter network group to generate three components of output light fields. Step 2: Input the three-component output light field into the balanced zero-beat detection device group to obtain the orthogonal amplitude component and orthogonal phase component of the three-component output light field; Step 3: Determine whether the three-component output light field meets the determination condition of the GHZ-type entangled state light field. If not, repeat steps 1-2 until the obtained three-component output light field meets the determination condition of the GHZ-type entangled state light field, and obtain the three-component GHZ entangled light field. Step 4: Load the phase shift signal to be measured into any two components of the three-component GHZ entangled optical field through the signal loading module group to obtain the multi-signal three-component GHZ entangled optical field. Repeat steps 1 and 2 for the multi-signal three-component GHZ entangled optical field to obtain the orthogonal amplitude component and orthogonal phase component of the three-component output optical field after phase shift. Step 5: Construct corresponding joint measurement operators based on the orthogonal amplitude components and orthogonal phase components of the three-component output light field after phase shift, and calculate and extract the measurement sensitivity of each phase shift signal to be measured through the joint measurement operators.

[0011] The second technical solution of the present invention is further characterized by: The specific process of step 1 is as follows: The three coherent light fields generated by the laser By inputting the data into the first, second, and third optical parametric amplifiers respectively, a compressed optical field is obtained. Compress the light field Input to the first beam splitter, and combine the light field output by the first beam splitter with the compressed light field. The input is fed into the second beam splitter, and after network coupling, a three-component output optical field is obtained. The expression is: (1) (2) (3) In equations (1) to (3), It consists of three coherent light fields. To compress the light field, It is a three-component output light field.

[0012] The calculation process for the orthogonal amplitude components and orthogonal phase components of the three-component output optical field in step 2 is as follows: (4) (5) (6) (7) (8) (9) In equations (4) to (9), These represent the orthogonal amplitude components of the three output light fields, respectively. These represent the orthogonal phase components of the three output light fields.

[0013] The process of determining whether the three-component output light field satisfies the criterion for a GHZ-type entangled state light field in step 3 is as follows: The van Loock-Furusawa criterion was used to determine whether the three sets of output light fields satisfied the GHZ-type entangled state light field, and to confirm whether the three components of the output light field violated the following inequalities: (10) (11) (12) For the three inequalities in equations (10) to (12), violating any one of them leads to the conclusion that at least two modes of optical field are entangled; violating at least two inequalities leads to the conclusion that the three modes of optical field are completely inseparable; when all three inequalities are violated, the resulting three-component output optical field satisfies the criterion for a GHZ-type entangled optical field; in equations (10) to (12), vacuum noise: , These represent the orthogonal amplitude components of the three output light fields, respectively. These represent the orthogonal phase components of the three output light fields.

[0014] The calculation process for the orthogonal amplitude components and orthogonal phase components of the three-component output optical field after phase shift in step 4 is as follows: (13) (14) (15) (16) (17) (18) In equations (13)-(18), These are the orthogonal amplitude components of the three-component output light field after phase shift. These are the orthogonal phase components of the three-component output optical field after phase shift. The compressed optical field after passing through an optical parametric amplifier array for a multi-signal, three-component GHZ entangled optical field. The output optical field after step 1 is the multi-signal three-component GHZ entangled optical field. and This represents the phase shift signal to be measured.

[0015] The construction process of the joint measurement operator in step 5 is as follows: The joint measurement operator corresponding to the phase shift signal under test is constructed by summing the orthogonal phase components of the three-component output optical fields, or by performing a difference operation on the orthogonal amplitude components of some components. .

[0016] The process for calculating the sensitivity of the phase shift signal under test in step 5 is as follows: Combine the measurement operators... By substituting the variance of the sample and its response sensitivity to the phase shift to be measured into the error transfer function, the measurement sensitivity of each phase shift signal to be measured can be calculated and extracted. The specific expression is as follows: (19) In equation (19), For joint measurement operators, δ The phase shift signal to be measured Characterizing the intensity of statistical fluctuations in measurement results, This indicates the sensitivity of the measured signal to changes in phase shift. Phase shift signal under test and The expression for the measurement sensitivity is as follows: (20) (twenty one) In equations (20) and (21), The phase shift signal to be measured The corresponding joint measurement operator, The phase shift signal to be measured The corresponding joint measurement operator, G is the linear gain coefficient, representing the amplification of the input optical field amplitude, and g is the parametric gain coefficient, corresponding to the contribution of photon pairs generated by the nonlinear process. Let be the average number of photons in the coherent state, which, under ideal lossless conditions, can be written as: and ,in r For compression parameters, To compress the phase and satisfy the constraint relationship , e is the Euler number constant e = 2.71828.

[0017] The beneficial effects of this invention are as follows: This invention is a multi-signal detection device based on quantum entanglement and joint measurement. It employs a modular optical structure design and achieves quantum-enhanced measurement functionality through the synergistic effects of compressed light source, entangled state preparation, interferometry, and joint detection. This device possesses advantages such as high sensitivity, strong noise resistance, good parameter measurement consistency, strong scalability, and ease of integration. It can effectively reduce the impact of quantum noise on detection results and improve the detection capability of weak signals. Simultaneously, the device structure is relatively simple, has good compatibility with existing optical platforms, and is easy to deploy in engineering and experimental implementation. It has broad application prospects in fields such as precision measurement, quantum sensing, weak signal detection, and quantum information processing.

[0018] This invention presents a multi-signal detection method based on quantum entanglement and joint measurement. By introducing quantum entanglement resources and combining them with a joint measurement mechanism, it achieves a significant improvement in the sensitivity of multi-parameter measurements. Compared with traditional measurement methods, this invention enables the measurement accuracy of multiple parameters to break through the standard quantum limit and reach the quantum Cramer-Rao bound of the system; at the same time, the estimation accuracy of each parameter exhibits good consistency. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the multi-signal detection device based on entanglement characteristics and joint measurement according to the present invention; Figure 2 This is a schematic diagram of the multi-signal detection method based on entanglement characteristics and joint measurement of the present invention; Figure 3 In Embodiment 5 of the multi-signal detection method based on entanglement characteristics and joint measurement of the present invention, the average number of photons in the coherent state is... Under the given conditions, the measurement sensitivity of the phase shift signal under test varies with the compression parameter. Figure 4 In Embodiment 6 of the multi-signal detection method based on entanglement characteristics and joint measurement of the present invention, the average number of photons in the coherent state is... The graph shows the variation of the measurement sensitivity of the phase shift signal under test with the compression parameter under the given conditions.

[0020] In the figure, 1. Laser, 2. Optical parametric amplifier group, 3. Signal loading module group, 4. Beam splitter network group, 5. Balanced zero-beat detection device group, 6. First optical parametric amplifier, 7. Second optical parametric amplifier, 8. Second optical parametric amplifier, 9. Signal loading module, 10. First beam splitter, 11. Second beam splitter, 12. Balanced zero-beat detection device. Detailed Implementation

[0021] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0022] The multi-signal detection method based on quantum entanglement and joint measurement of the present invention is illustrated through six embodiments. The detection devices used in the following embodiments are as follows: This invention relates to a multi-signal detection device based on quantum entanglement and joint measurement, the structure of which is as follows: Figure 1 As shown, the system includes a laser 1, an optical parametric amplifier group 2, a signal loading module group 3, a beam splitter network group 4, and a balanced zero-beat detection device group 5 arranged sequentially along the optical path. The laser 1 is an internal cavity frequency-doubled tunable single-frequency Nd:YAP / LBO all-solid-state laser capable of simultaneously outputting 1080 nm infrared light and 540 nm green light. The optical parametric amplifier group 2 includes a first optical parametric amplifier 6, a second optical parametric amplifier 7, and a third optical parametric amplifier 8 arranged in parallel along a direction perpendicular to the optical path. Each of these amplifiers consists of a nonlinear crystal and two concave mirrors. The beam splitter network group 4 includes a first beam splitter 10 and a second beam splitter 11. The first beam splitter 10 has a transmission-to-reflection ratio of 1:2, and the second beam splitter 11 has a transmission-to-reflection ratio of 1:1. The first beam splitter 10 and the second beam splitter 11 are respectively locked to... and Phase. Signal loading module group 3 includes no less than 2 signal loading modules 9, and balance zero-beat detection device group 5 includes 3 balance zero-beat detection devices 12.

[0023] The first optical parametric amplifier 6 is used to generate an orthogonal phase-compressed optical field; the second optical parametric amplifier 7 and the third optical parametric amplifier 8 are both used to generate an orthogonal amplitude-compressed optical field; the first beam splitter 10 and the second beam splitter 11 are used to couple the compressed optical fields generated by the first optical parametric amplifier 6, the second optical parametric amplifier 7 and the third optical parametric amplifier 8; the signal loading module 9 is used to introduce multiple weak signals to be measured into the optical field; the balanced zero-beat detection device 12 is used to extract the orthogonal amplitude component and the orthogonal phase component of the optical field.

[0024] Example 1 A multi-signal detection method based on quantum entanglement and joint measurement, the principle of which is as follows: Figure 2 As shown, the specific testing steps are as follows: Step 1: Input the three coherent light fields generated by the laser into the optical parametric amplifier group respectively. The optical parametric amplifier group outputs three compressed light fields. The three compressed light fields are interferometrically coupled through the beam splitter network group to generate three components of output light fields. Step 2: Input the three-component output light field into the balanced zero-beat detection device group 5 to obtain the orthogonal amplitude component and orthogonal phase component of the three-component output light field; Step 3: Determine whether the three-component output light field meets the determination condition of the GHZ-type entangled state light field. If not, repeat steps 1-2 until the obtained three-component output light field meets the determination condition of the GHZ-type entangled state light field, and obtain the three-component GHZ entangled light field. Step 4: Load the phase shift signal to be measured into any two components of the three-component GHZ entangled optical field through the signal loading module group to obtain the multi-signal three-component GHZ entangled optical field. Repeat steps 1 and 2 for the multi-signal three-component GHZ entangled optical field to obtain the orthogonal amplitude component and orthogonal phase component of the three-component output optical field after phase shift. Step 5: Construct corresponding joint measurement operators based on the orthogonal amplitude components and orthogonal phase components of the three-component output light field after phase shift, and calculate and extract the measurement sensitivity of each phase shift signal to be measured through the joint measurement operators.

[0025] Example 2 A multi-signal detection method based on quantum entanglement and joint measurement, the principle of which is as follows: Figure 2 As shown, the specific testing steps are as follows: Step 1: Input the three coherent light fields generated by the laser into an optical parametric amplifier group, which outputs three compressed light fields. These three compressed light fields are then interferometrically coupled through a beam splitter network to generate three component output light fields. The specific process is as follows: The three coherent light fields generated by the laser By inputting the data into the first, second, and third optical parametric amplifiers respectively, a compressed optical field is obtained. Compress the light field Input to the first beam splitter, and combine the light field output by the first beam splitter with the compressed light field. The input is fed into the second beam splitter, and after network coupling, a three-component output optical field is obtained. The expression is: (1) (2) (3) In equations (1) to (3), It consists of three coherent light fields. To compress the light field, It is a three-component output light field.

[0026] Step 2: Input the three-component output light field into the balanced zero-beat detection device group 5 to obtain the orthogonal amplitude component and orthogonal phase component of the three-component output light field; The calculation process for the orthogonal amplitude components and orthogonal phase components of the three-component output optical field is as follows: (4) (5) (6) (7) (8) (9) In equations (4) to (9), These represent the orthogonal amplitude components of the three output light fields, respectively. These represent the orthogonal phase components of the three output light fields.

[0027] Step 3: Determine whether the three-component output light field meets the determination condition of the GHZ-type entangled state light field. If not, repeat steps 1-2 until the obtained three-component output light field meets the determination condition of the GHZ-type entangled state light field, and obtain the three-component GHZ entangled light field. The specific determination process is as follows: The van Loock-Furusawa criterion was used to determine whether the three sets of output light fields satisfied the GHZ-type entangled state light field, and to confirm whether the three components of the output light field violated the following inequalities: (10) (11) (12) For the three inequalities in equations (10) to (12), violating any one of them leads to the conclusion that at least two modes of optical field are entangled; violating at least two inequalities leads to the conclusion that the three modes of optical field are completely inseparable; when all three inequalities are violated, the resulting three-component output optical field satisfies the criterion for a GHZ-type entangled optical field; in equations (10) to (12), vacuum noise: , These represent the orthogonal amplitude components of the three output light fields, respectively. These represent the orthogonal phase components of the three output light fields.

[0028] In this embodiment: (twenty two) (twenty three) (twenty four) In equations (22)-(24), These represent the orthogonal amplitude components of the three-component GHZ entangled optical field, respectively. Let represent the orthogonal phase components of the three-component GHZ entangled optical field respectively. All three inequalities have been violated, thus proving that the optical field generated in step 1 satisfies the criterion for a GHZ-type entangled optical field.

[0029] Step 4: Load the phase shift signal to be measured into any two components of the three-component GHZ entangled optical field through the signal loading module group to obtain the multi-signal three-component GHZ entangled optical field. Repeat steps 1 and 2 for the multi-signal three-component GHZ entangled optical field to obtain the orthogonal amplitude component and orthogonal phase component of the three-component output optical field after phase shift. Step 5: Construct corresponding joint measurement operators based on the orthogonal amplitude components and orthogonal phase components of the three-component output light field after phase shift, and calculate and extract the measurement sensitivity of each phase shift signal to be measured through the joint measurement operators.

[0030] Example 3 A multi-signal detection method based on quantum entanglement and joint measurement, the principle of which is as follows: Figure 2 As shown, the specific testing steps are as follows: Step 1: Input the three coherent light fields generated by the laser into an optical parametric amplifier group, which outputs three compressed light fields. These three compressed light fields are then interferometrically coupled through a beam splitter network to generate three component output light fields. The specific process is as follows: The three coherent light fields generated by the laser By inputting the data into the first, second, and third optical parametric amplifiers respectively, a compressed optical field is obtained. Compress the light field Input to the first beam splitter, and combine the light field output by the first beam splitter with the compressed light field. The input is fed into the second beam splitter, and after network coupling, a three-component output optical field is obtained. The expression is: (1) (2) (3) In equations (1) to (3), It consists of three coherent light fields. To compress the light field, It is a three-component output light field.

[0031] Step 2: Input the three-component output light field into the balanced zero-beat detection device group 5 to obtain the orthogonal amplitude component and orthogonal phase component of the three-component output light field; The calculation process for the orthogonal amplitude components and orthogonal phase components of the three-component output optical field is as follows: (4) (5) (6) (7) (8) (9) In equations (4) to (9), These represent the orthogonal amplitude components of the three output light fields, respectively. These represent the orthogonal phase components of the three output light fields.

[0032] Step 3: Determine whether the three-component output light field meets the determination condition of the GHZ-type entangled state light field. If not, repeat steps 1-2 until the obtained three-component output light field meets the determination condition of the GHZ-type entangled state light field, and obtain the three-component GHZ entangled light field. The specific determination process is as follows: The van Loock-Furusawa criterion was used to determine whether the three sets of output light fields satisfied the GHZ-type entangled state light field, and to confirm whether the three components of the output light field violated the following inequalities: (10) (11) (12) For the three inequalities in equations (10) to (12), violating any one of them leads to the conclusion that at least two modes of optical field are entangled; violating at least two inequalities leads to the conclusion that the three modes of optical field are completely inseparable; when all three inequalities are violated, the resulting three-component output optical field satisfies the criterion for a GHZ-type entangled optical field; in equations (10) to (12), vacuum noise: , These represent the orthogonal amplitude components of the three output light fields, respectively. These represent the orthogonal phase components of the three output light fields.

[0033] In this embodiment: (twenty two) (twenty three) (twenty four) In equations (22)-(24), These represent the orthogonal amplitude components of the three-component GHZ entangled optical field, respectively. Let represent the orthogonal phase components of the three-component GHZ entangled optical field respectively. All three inequalities have been violated, thus proving that the optical field generated in step 1 satisfies the criterion for a GHZ-type entangled optical field.

[0034] Step 4: Load the phase shift signal to be measured into any two components of the three-component GHZ entangled optical field through the signal loading module group to obtain the multi-signal three-component GHZ entangled optical field. Repeat steps 1 and 2 for the multi-signal three-component GHZ entangled optical field to obtain the orthogonal amplitude component and orthogonal phase component of the three-component output optical field after phase shift. The calculation process for the orthogonal amplitude components and orthogonal phase components of the three-component output optical field after phase shift in step 4 is as follows: (13) (14) (15) (16) (17) (18) In equations (13)-(18), These are the orthogonal amplitude components of the three-component output light field after phase shift. These are the orthogonal phase components of the three-component output optical field after phase shift. The compressed optical field after passing through an optical parametric amplifier array for a multi-signal, three-component GHZ entangled optical field. The output optical field after step 1 is the multi-signal three-component GHZ entangled optical field. and This represents the phase shift signal to be measured.

[0035] Step 5: Construct corresponding joint measurement operators based on the orthogonal amplitude components and orthogonal phase components of the three-component output light field after phase shift, and calculate and extract the measurement sensitivity of each phase shift signal to be measured through the joint measurement operators.

[0036] Example 4 This invention is a multi-signal detection method based on quantum entanglement and joint measurement, the principle of which is as follows: Figure 2 As shown, the specific testing steps are as follows: Step 1: Input the three coherent light fields generated by laser 1 into optical parametric amplifier group 2 respectively. Optical parametric amplifier group 2 outputs three compressed light fields. The three compressed light fields are interfered and coupled by beam splitter network group 4 to generate three-component output light fields. Step 1: The specific steps are as follows: The three coherent light fields generated by laser 1 By inputting the first optical parametric amplifier 6, the second optical parametric amplifier 7, and the third optical parametric amplifier 8 respectively, a compressed optical field is obtained. Compress the light field Input to the first beam splitter 10, and combine the light field output by the first beam splitter 10 with the compressed light field. The input to the second beam splitter 11, after network coupling, yields a three-component output optical field. The expression is: (1) (2) (3) In equations (1) to (3), It consists of three coherent light fields. To compress the light field, It is a three-component output light field.

[0037] Step 2: Input the three-component output light field into the balanced zero-beat detection device group 5 to obtain the orthogonal amplitude component and orthogonal phase component of the three-component output light field; The calculation process for the orthogonal amplitude components and orthogonal phase components of the three-component output optical field is as follows: (4) (5) (6) (7) (8) (9) In equations (4) to (9), These represent the orthogonal amplitude components of the three output light fields, respectively. These represent the orthogonal phase components of the three output light fields.

[0038] Step 3: Determine whether the three-component output light field meets the determination condition of the GHZ-type entangled state light field. If not, repeat steps 1-2 until the obtained three-component output light field meets the determination condition of the GHZ-type entangled state light field, and obtain the three-component GHZ entangled light field. The process for determining whether the three-component output light field satisfies the criteria for a GHZ-type entangled state light field is as follows: The van Loock-Furusawa criterion was used to determine whether the three sets of output light fields satisfied the GHZ-type entangled state light field, and to confirm whether the three components of the output light field violated the following inequalities: (10) (11) (12) For the three inequalities in equations (10) to (12), violating any one of them leads to the conclusion that at least two modes of optical field are entangled; violating at least two inequalities leads to the conclusion that the three modes of optical field are completely inseparable; when all three inequalities are violated, the resulting three-component output optical field satisfies the criterion for a GHZ-type entangled optical field; in equations (10) to (12), vacuum noise: , These represent the orthogonal amplitude components of the three output light fields, respectively. These represent the orthogonal phase components of the three output light fields.

[0039] Step 4: Load the phase shift signal to be measured into any two components of the three-component GHZ entangled optical field through the signal loading module group 3 to obtain the multi-signal three-component GHZ entangled optical field. Repeat steps 1 and 2 for the multi-signal three-component GHZ entangled optical field to obtain the orthogonal amplitude component and orthogonal phase component of the three-component output optical field after phase shift. The calculation process for the orthogonal amplitude components and orthogonal phase components of the three-component output optical field after phase shift is as follows: (13) (14) (15) (16) (17) (18) In equations (13)-(18), These are the orthogonal amplitude components of the three-component output light field after phase shift. These are the orthogonal phase components of the three-component output optical field after phase shift. The compressed optical field after passing through an optical parametric amplifier array for a multi-signal, three-component GHZ entangled optical field. The output optical field after step 1 is the multi-signal three-component GHZ entangled optical field. and There are two phase shift signals to be tested.

[0040] Step 5: Construct corresponding joint measurement operators based on the orthogonal amplitude components and orthogonal phase components of the three-component output light field after phase shift, and calculate and extract the measurement sensitivity of each phase shift signal to be measured through the joint measurement operators.

[0041] The construction process of the joint measurement operator is as follows: by summing the orthogonal phase components of the three-component output optical fields, or by performing a difference operation on the orthogonal amplitude components of some components, the joint measurement operator corresponding to the phase shift signal to be measured can be constructed. .

[0042] The calculation process for the sensitivity of the phase shift signal under test is as follows: Combine the measurement operators By substituting the variance of the sample and its response sensitivity to the phase shift to be measured into the error transfer function, the measurement sensitivity of each phase shift signal to be measured can be calculated and extracted. The specific expression is as follows: (19) In equation (19), For joint measurement operators, δ The phase shift signal to be measured Characterizing the intensity of statistical fluctuations in measurement results, This indicates the sensitivity of the measured signal to changes in phase shift. Phase shift signal under test and The expression for the measurement sensitivity is as follows: (20) (twenty one) In equations (20) and (21), The phase shift signal to be measured The corresponding joint measurement operator, The phase shift signal to be measured The corresponding joint measurement operator, G is the linear gain coefficient, representing the amplification of the input optical field amplitude, and g is the parametric gain coefficient, corresponding to the contribution of photon pairs generated by the nonlinear process. In this embodiment, the average number of photons in the coherent state is... , r The parameters are for compression and satisfy the constraints. , e is the Euler number constant e = 2.71828.

[0043] Example 5 The difference from Example 4 is that the average number of photons in the coherent state in this example is... .

[0044] Figure 3 Represents the average number of photons in the coherent state. Under the given conditions, the measurement sensitivity of the phase shift signal under test varies with the compression parameter. As shown in the figure, the parameter estimation sensitivity increases with the increase of the compression parameter under different optical field intensities, and the parameter estimation sensitivity based on joint measurement can break through the shot noise limit. Comparing the sensitivity with that of individual measurements, it can be found that the joint measurement sensitivity based on entanglement characteristics is closer to the quantum Cramer-Rao limit throughout the entire compression range. The introduction of non-classical states reduces the quantum fluctuations of a certain orthogonal component, thereby reducing noise. The noise reduction becomes more significant with increasing compression parameters, leading to an improvement in measurement sensitivity.

[0045] Example 6 The difference from Example 4 is that the average number of photons in the coherent state in this example is... .

[0046] Figure 4 Represents the average number of photons in the coherent state. Under the given conditions, the measurement sensitivity of the phase shift signal under test varies with the compression parameter. As shown in the figure, the parameter estimation sensitivity increases with the increase of the compression parameter under different light field intensities, and the parameter estimation sensitivity based on joint measurement can break through the shot noise limit. Comparing the sensitivity with that under individual measurements, it can be found that the joint measurement sensitivity based on entanglement characteristics is closer to the quantum Cramer-Rao limit throughout the entire compression range. The introduction of non-classical states reduces the quantum fluctuations of a certain orthogonal component, thereby reducing noise. The noise reduction becomes more significant with increasing compression parameters, leading to an increase in measurement sensitivity. The slight difference between the measurement sensitivity and the quantum Cramer-Rao limit under different light field intensities is fundamentally due to the change in the dominance of different contributing terms in the quantum Fisher information. In the weak light region, terms related to quantum fluctuations in the quantum Fisher information make significant contributions, and these terms are distributed across multiple orthogonal components. The joint measurement scheme cannot fully extract all the information, resulting in a measurement accuracy slightly higher than QCRB. As the coherent light intensity increases, the signal terms related to the change in the average value gradually become dominant, so the parameter information is mainly reflected in the expected value change of the observable quantity. Joint measurement is the optimal measurement scheme under this condition, so the measurement sensitivity almost completely overlaps with QCRB.

Claims

1. A multi-signal detection device based on quantum entanglement and joint measurement, characterized in that, It includes a laser (1), an optical parametric amplifier group (2), a signal loading module group (3), a beam splitter network group (4), and a balanced zero-beat detection device group (5) arranged sequentially along the optical path. The optical parametric amplifier group (2) includes a first optical parametric amplifier (6), a second optical parametric amplifier (7), and a third optical parametric amplifier (8) arranged side by side along a direction perpendicular to the optical path; the beam splitter network group (4) includes a first beam splitter (10) and a second beam splitter (11); the signal loading module group (3) includes no less than two signal loading modules (9); and the balanced zero-beat detection device group (5) includes three balanced zero-beat detection devices (12). The first optical parametric amplifier (6) is used to generate an orthogonal phase compression optical field, and the second optical parametric amplifier (7) and the third optical parametric amplifier (8) are both used to generate an orthogonal amplitude compression optical field; the first beam splitter (10) and the second beam splitter (11) are used to couple the compression optical fields generated by the first optical parametric amplifier (6), the second optical parametric amplifier (7) and the third optical parametric amplifier (8); the signal loading module (9) is used to introduce multiple weak signals to be measured into the optical field; the balanced zero-beat detection device (12) is used to extract the orthogonal amplitude component and the orthogonal phase component of the optical field.

2. The multi-signal detection device based on quantum entanglement and joint measurement according to claim 1, characterized in that, The first beam splitter (10) has a transmission-to-reflection ratio of 1:2, and the second beam splitter (11) has a transmission-to-reflection ratio of 1:

1. The first beam splitter (10) and the second beam splitter (11) are respectively locked to... and Phase.

3. The multi-signal detection device based on quantum entanglement and joint measurement according to claim 1, characterized in that, The laser (1) is a single-frequency Nd:YAP / LBO all-solid-state laser with tunable internal cavity frequency doubling; the first optical parametric amplifier (6), the second optical parametric amplifier (7) and the third optical parametric amplifier (8) are all composed of a nonlinear crystal and two concave mirrors.

4. A multi-signal detection method based on quantum entanglement and joint measurement, characterized in that, The detection is achieved using the apparatus described in any one of claims 1-3, and the specific detection steps are as follows: Step 1: Input the three coherent light fields generated by the laser (1) into the optical parametric amplifier group (2) respectively. The optical parametric amplifier group (2) outputs three compressed light fields. The three compressed light fields are interfered and coupled by the beam splitter network group (4) to generate three-component output light fields. Step 2: Input the three-component output light field into the balanced zero-beat detection device group (5) to obtain the orthogonal amplitude component and orthogonal phase component of the three-component output light field; Step 3: Determine whether the three-component output light field meets the determination condition of the GHZ-type entangled state light field. If not, repeat steps 1-2 until the obtained three-component output light field meets the determination condition of the GHZ-type entangled state light field, and obtain the three-component GHZ entangled light field. Step 4: Load the phase shift signal to be measured into any two components of the three-component GHZ entangled optical field through the signal loading module group (3) to obtain a multi-signal three-component GHZ entangled optical field. Repeat steps 1 and 2 for the multi-signal three-component GHZ entangled optical field to obtain the orthogonal amplitude component and orthogonal phase component of the three-component output optical field after phase shift. Step 5: Construct corresponding joint measurement operators based on the orthogonal amplitude components and orthogonal phase components of the three-component output light field after phase shift, and calculate and extract the measurement sensitivity of each phase shift signal to be measured through the joint measurement operators.

5. The multi-signal detection method based on quantum entanglement and joint measurement according to claim 4, characterized in that, The specific process of step 1 is as follows: The three coherent light fields generated by the laser (1) The compressed optical field is obtained by inputting the first optical parametric amplifier (6), the second optical parametric amplifier (7), and the third optical parametric amplifier (8) respectively. Compress the light field Input to the first beam splitter (10), and combine the light field output by the first beam splitter (10) with the compressed light field. The input is to the second beam splitter (11), and after network coupling, three components of the output optical field are obtained. The expression is: (1) (2) (3) In equations (1) to (3), It consists of three coherent light fields. To compress the light field, It is a three-component output light field.

6. The multi-signal detection method based on quantum entanglement and joint measurement according to claim 4, characterized in that, The calculation process for the orthogonal amplitude components and orthogonal phase components of the three-component output optical field mentioned in step 2 is as follows: (4) (5) (6) (7) (8) (9) In equations (4) to (9), These represent the orthogonal amplitude components of the three output light fields, respectively. These represent the orthogonal phase components of the three output light fields.

7. The multi-signal detection method based on quantum entanglement and joint measurement according to claim 4, characterized in that, The process for determining whether the three-component output light field satisfies the criterion for a GHZ-type entangled state light field in step 3 is as follows: The van Loock-Furusawa criterion was used to determine whether the three sets of output light fields satisfied the GHZ-type entangled state light field, and to confirm whether the three components of the output light field violated the following inequalities: (10) (11) (12) For the three inequalities (10) to (12), violating any one of them leads to the conclusion that at least two modes of optical fields are entangled; violating at least two inequalities leads to the conclusion that the three modes of optical fields are completely inseparable; when all three inequalities are violated, the resulting three-component output optical fields satisfy the judgment condition of GHZ-type entangled optical fields. In equations (10)-(12), vacuum noise: , These represent the orthogonal amplitude components of the three output light fields, respectively. These represent the orthogonal phase components of the three output light fields.

8. The multi-signal detection method based on quantum entanglement and joint measurement according to claim 4, characterized in that, The calculation process for the orthogonal amplitude components and orthogonal phase components of the three-component output optical field after phase shift in step 4 is as follows: (13) (14) (15) (16) (17) (18) In equations (13)-(18), These are the orthogonal amplitude components of the three-component output light field after phase shift. These are the orthogonal phase components of the three-component output optical field after phase shift. The compressed optical field after passing through an optical parametric amplifier array for a multi-signal, three-component GHZ entangled optical field. The output optical field after step 1 is the multi-signal three-component GHZ entangled optical field. and There are two phase shift signals to be tested.

9. The multi-signal detection method based on quantum entanglement and joint measurement according to claim 4, characterized in that, The construction process of the joint measurement operator in step 5 is as follows: The joint measurement operator corresponding to the phase shift signal to be measured is constructed by summing the orthogonal phase components of the three-component output optical fields, or by performing a difference operation on the orthogonal amplitude components of some components. .

10. The multi-signal detection method based on quantum entanglement and joint measurement according to claim 9, characterized in that, The process for calculating the sensitivity of the phase shift signal under test in step 5 is as follows: The joint measurement operator... By substituting the variance of the sample and its response sensitivity to the phase shift to be measured into the error transfer function, the measurement sensitivity of each phase shift signal to be measured can be calculated and extracted. The specific expression is as follows: (19) In equation (19), For joint measurement operators, δ The phase shift signal to be measured, Characterizing the intensity of statistical fluctuations in measurement results, This indicates the sensitivity of the measured signal to changes in phase shift. Phase shift signal under test and The expression for the measurement sensitivity is as follows: (20) (21) In equations (20) and (21), The phase shift signal to be measured The corresponding joint measurement operator, The phase shift signal to be measured The corresponding joint measurement operator, G is the linear gain coefficient, representing the amplification of the input optical field amplitude, and g is the parametric gain coefficient, corresponding to the contribution of photon pairs generated by the nonlinear process. Let be the average number of photons in the coherent state, which, under ideal lossless conditions, can be written as: and ,in r For compression parameters, To compress the phase and satisfy the constraint relationship , e is the Euler number constant e = 2.71828.

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