Experimental device for simulating quantum entangled state measurement and quantum teleportation by using classical light source

Abstract

The invention discloses an experimental device for simulating quantum entangled state measurement and quantum teleportation by using a classical light source, which comprises the following steps: after a first light beam is emitted by an entangled light source simulation module through a laser light source, carrying out polarization and beam splitting treatment to generate two polarized light paths for simulating spatially separated entangled photon pairs; a second light beam is emitted by a laser light source through a simulated unknown quantum state generation module and then is subjected to polarization and beam splitting processing, two second polarized light beams which are used for simulating generation of unknown quantum states and are orthogonal in polarization direction and equal in intensity are generated, and polarized light beams output by an Alice end, a Bob end and a Cindy end are measured respectively. The light intensity data of the polarized light beam under a plurality of preset measurement bases are measured, the light intensity data are converted into coincidence counts in combination with a preset counting rule, the light path configuration of quantum entangled state measurement and quantum teleportation is determined according to the coincidence counts, and the experimental device has good stability and repeatability.

Description

Technical Field

[0001] This invention relates to the field of quantum optical experimental equipment technology, and in particular to an experimental device for simulating quantum entangled state measurement and quantum teleportation using classical light sources. Background Technology

[0002] Quantum entanglement and teleportation are core concepts in quantum information science, holding significant importance in both theoretical research and practical applications. With the development of quantum technology, experiments involving quantum entanglement and teleportation have become a hot topic in current quantum research.

[0003] Currently, quantum entanglement and teleportation experiments rely on spontaneous parametric downconversion (SPDC) technology, which typically requires specialized equipment such as BBO nonlinear crystals and single-photon detectors. This not only results in high costs but also complex optical path structures, difficult debugging, stringent experimental environment requirements, and susceptibility to interference. Consequently, quantum entanglement and teleportation experiments are costly and unstable, limiting their promotion and application, particularly in teaching. Summary of the Invention

[0004] In view of this, in order to solve the above-mentioned technical problems, the present invention provides an experimental device for simulating quantum entangled state measurement and quantum teleportation using classical light sources.

[0005] The first aspect of the present invention provides an experimental apparatus for simulating quantum entangled state measurement and quantum teleportation using a classical light source, comprising: a simulated entangled light source module, a simulated unknown quantum state generation module, a measurement module, and a data processing module;

[0006] The simulated entanglement light source module is used to generate two polarized light paths for simulating entangled photon pairs separated in space after the first beam is emitted by the first laser light source and then processed by polarization and beam splitting. Each of the polarized light paths contains two first polarized beams with mutually orthogonal polarization directions and equal intensity, and the two polarized light paths correspond to the output channels of Alice end and Bob end, respectively.

[0007] The module for simulating unknown quantum states is used to generate two second polarized beams with mutually orthogonal polarization directions and equal intensity after the second beam is emitted by the second laser source and processed by polarization and beam splitting. The two second polarized beams correspond to the output channel of the Cindy end.

[0008] The measurement module is used to measure the polarized beams output from the Alice end, the Bob end, and the Cindy end under multiple preset measurement bases, obtain the light intensity data of the polarized beams under multiple preset measurement bases, and transmit the light intensity data to the data processing module.

[0009] The data processing module is used to receive the light intensity data from the measurement module, and convert the light intensity data into coincidence counts in combination with a preset counting rule, and determine the optical path configuration for quantum entanglement state measurement and quantum teleportation based on the coincidence counts.

[0010] Preferably, the simulated entanglement light source module includes a first laser light source, a first aperture, a first half-wave plate, a first polarization beam splitter, a first beam splitter, and a second beam splitter. The first laser light source emits a first beam, which is then intensity-modulated by the first aperture. The beam then passes through the first half-wave plate and the first polarization beam splitter to generate a first horizontal polarization component and a first vertical polarization component. The first horizontal polarization component and the first vertical polarization component are split by the first beam splitter and the second beam splitter, respectively, to form two polarization optical paths. Each polarization optical path contains two first polarization beams with mutually orthogonal polarization directions and equal intensity.

[0011] Preferably, the simulated unknown quantum state generation module includes a second laser source, a second aperture, a second half-wave plate, and a second polarization beam splitter; the second beam emitted by the second laser source is intensity-modulated by the second aperture, and then passes through the second half-wave plate and the second polarization beam splitter in sequence, splitting into two second polarized beams with mutually orthogonal polarization directions and equal intensity.

[0012] Preferably, the measurement module includes a polarizer and a photodetector; the polarizer and the photodetector are arranged opposite to each other, the polarizer is used to limit the polarized beam by polarization angle to form a plurality of preset polarized beams under the measurement base, and the photodetector is used to acquire the light intensity data of the polarized beams under each of the preset measurement bases.

[0013] Preferably, the measurement module further includes a third half-wave plate, which is disposed on the optical path of the polarizer away from the photodetector, and is used to perform quantum gate operation by limiting the angle.

[0014] Preferably, the extinction ratio of both the polarizer and the third half-wave plate is greater than or equal to 100:1.

[0015] Preferably, the data processing module is used to calculate a first coincidence count based on the light intensity data at the Alice end and the Bob end, combined with the preset counting rules; determine the measured probability distribution of the reconstructed Bell state measurement based on the first coincidence count; determine the fidelity based on the measured probability distribution and quantum state tomography; determine whether the fidelity is greater than or equal to a preset fidelity threshold; if the fidelity is less than the preset fidelity threshold, recalibrate the configuration parameters of the optical path elements in the experimental device until the fidelity is greater than or equal to the preset fidelity threshold, thereby obtaining the optical path configuration for simulating quantum entangled state measurement.

[0016] Preferably, the data processing module is used to calculate a second coincidence count based on the light intensity data of the Alice end and the Cindy end, combined with the preset counting rule, and to project the polarization state of the Alice end and the unknown polarization state of the Cindy end to the target Bell state based on the second coincidence count; it is also used to determine the solution of the unknown polarization state of the Cindy end based on the light intensity data of the Bob end after the quantum gate operation;

[0017] The solution of the unknown polarization state at the Cindy end is compared with the preset polarization state at the Cindy end. If the solution of the unknown polarization state at the Cindy end is inconsistent with the preset polarization state at the Cindy end, the configuration parameters of the optical path elements in the experimental device are recalibrated until the solution of the unknown polarization state at the Cindy end is consistent with the preset polarization state at the Cindy end, thus obtaining the optical path configuration for simulating quantum teleportation.

[0018] Preferably, the splitting ratio of the first beam splitter and the second beam splitter is 50%:50%.

[0019] Secondly, the present invention also provides an experimental method based on the experimental apparatus described in the first aspect, which uses a classical light source to simulate quantum entangled state measurement and quantum teleportation, comprising:

[0020] After the first beam is emitted by the first laser source, it undergoes polarization and beam splitting to generate two polarized optical paths for simulating entangled photon pairs separated in space. Each polarized optical path contains two first polarized beams with mutually orthogonal polarization directions and equal intensity. The two polarized optical paths correspond to the output channels of the Alice end and the Bob end, respectively.

[0021] After the second beam is emitted by the second laser source, it is polarized and split to generate two second polarized beams with mutually orthogonal polarization directions and equal intensity, which are used to simulate the generation of unknown quantum states. The two second polarized beams correspond to the output channels of the Cindy end.

[0022] After measuring the polarized beams output from the Alice end, the Bob end, and the Cindy end under multiple preset measurement bases, the light intensity data of the polarized beams under multiple preset measurement bases are obtained.

[0023] The light intensity data is converted into coincidence counts by combining the preset counting rules, and the optical path configuration for quantum entanglement state measurement and quantum teleportation is determined based on the coincidence counts.

[0024] As can be seen from the above technical solution, this invention uses classical optical elements to construct an experimental device for simulating quantum entanglement measurement and quantum teleportation. The simulated entanglement light source module emits a first beam from a laser source, which is then polarized and split to generate two polarized optical paths for simulating the spatial separation of entangled photon pairs. These two polarized optical paths correspond to the output channels of the Alice and Bob ends, respectively. The simulated unknown quantum state generation module emits a second beam from a laser source, which is then polarized and split to generate two second polarized beams with mutually orthogonal polarization directions and equal intensity, used to simulate the generation of unknown quantum states. These two second polarized beams correspond to the Cindy end... The output channel is used as the input source for the unknown polarization state to be measured. A measurement module is also built to measure the polarization beams output from the Alice, Bob, and Cindy ends under multiple preset measurement bases. The light intensity data of the polarization beams under multiple preset measurement bases are measured, and the light intensity data is converted into coincidence counts based on preset counting rules. The optical path configuration for quantum entanglement state measurement and quantum teleportation is determined based on the coincidence counts. Thus, the simulation experiment is realized using a classical light source. There is no quantum state decoherence problem. The experimental results are minimally affected by environmental interference, have high stability, and can accurately reproduce the mathematical logic and core characteristics of quantum entanglement and teleportation, with good repeatability. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 A schematic diagram of the structure of an experimental device for simulating quantum entangled state measurement and quantum teleportation using a classical light source, provided in an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of the structure of the simulated entanglement light source module provided in an embodiment of the present invention;

[0028] Figure 3This is a schematic diagram of the structure of the module for simulating unknown quantum states provided in an embodiment of the present invention;

[0029] Figure 4 This is a schematic diagram of the structure of the measurement module provided in an embodiment of the present invention;

[0030] Figure 5 A schematic diagram of the optical path for simulating quantum entangled state measurement provided in an embodiment of the present invention;

[0031] Figure 6 A graph showing the fidelity calculation results provided in an embodiment of the present invention;

[0032] Figure 7 This is a schematic diagram of the optical path for simulating quantum teleportation provided in an embodiment of the present invention;

[0033] Figure 8 This is a flowchart illustrating an experimental method for simulating quantum entangled state measurement and quantum teleportation using a classical light source, as provided in an embodiment of the present invention. Detailed Implementation

[0034] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] like Figure 1 As shown, this application provides an experimental device for simulating quantum entangled state measurement and quantum teleportation using a classical light source, including: a simulated entangled light source module 10, a simulated unknown quantum state generation module 20, a measurement module 30, and a data processing module 40;

[0036] The simulated entanglement light source module 10 is used to generate two polarized light paths for simulating the spatial separation of entangled photon pairs after the first beam emitted by the first laser light source 101 is polarized and split. Each polarized light path contains two first polarized beams with mutually orthogonal polarization directions and equal intensity, and the two polarized light paths correspond to the output channels of Alice end and Bob end, respectively.

[0037] like Figure 2As shown, the simulated entanglement light source module 10 includes a first laser light source 101, a first aperture 102, a first half-wave plate 103, a first polarization beam splitter 104, a first beam splitter 105, and a second beam splitter 106. The first laser light source 101 emits a first beam, which is then subjected to intensity modulation by the first aperture 102. The beam then passes through the first half-wave plate 103 and the first polarization beam splitter 104 in sequence to generate a first horizontal polarization component and a first vertical polarization component. The first horizontal polarization component and the first vertical polarization component are split by the first beam splitter 105 and the second beam splitter 106, respectively, to form two polarization optical paths. Each polarization optical path contains two first polarization beams with mutually orthogonal polarization directions and equal intensity.

[0038] The first beam splitter 105 and the second beam splitter 106 have a splitting ratio of 50%:50%, which ensures that the light intensity distribution of the two polarization paths is uniform and the splitting ratio error is controlled within ≤3%, so as to ensure the high fidelity of the simulated entangled state.

[0039] For example, the first laser source 101 outputs a visible light beam (e.g., 635nm). After the beam power is calibrated by the first aperture 102 (aperture 2-5mm), the beam passes sequentially through the first half-wave plate 103 and the first polarization beam splitter 104, splitting the incident light into horizontal (H) polarized light and vertical (V) polarized light (light intensity ratio ≈ 1:1). The two polarized beams are respectively incident on the first beam splitter 105 and the second beam splitter 106, and are each split into two polarized light paths in equal proportion. One polarized light path includes polarized beams H1 and V1 with equal intensity and orthogonal polarization directions, and the other polarized light path includes polarized beams H2 and V2 with equal intensity and orthogonal polarization directions. H1 and V1 constitute the output beam at the Alice end, and H2 and V2 constitute the output beam at the Bob end, to simulate entangled photon pairs that replace real quantum systems.

[0040] The module 20 for simulating unknown quantum states is used to generate two second polarized beams with mutually orthogonal polarization directions and equal intensity after the second beam is emitted by the second laser source 201 and then processed by polarization and beam splitting. The two second polarized beams correspond to the output channels of the Cindy end.

[0041] Among them, simulating unknown quantum states involves adding an unknown quantum state input optical path on the basis of an existing entangled channel to construct a complete optical path for teleportation, thereby realizing the simulated transmission and reconstruction of unknown quantum states.

[0042] Specifically, such as Figure 3As shown, the simulated unknown quantum state generation module 20 includes a second laser source 201, a second aperture 202, a second half-wave plate 203, and a second polarization beam splitter 204. The second beam emitted by the second laser source 201 is intensity-modulated by the second aperture 202, and then passes through the second half-wave plate 203 and the second polarization beam splitter 204 in sequence, splitting into two second polarized beams with mutually orthogonal polarization directions and equal intensity.

[0043] For example, the second laser source 201 outputs a beam with a wavelength of 635nm. After the light intensity is adjusted by the second aperture 202 (aperture 3mm), the polarization state is adjusted by the second half-wave plate 203, and then the beam is separated into horizontal and vertical polarization components by the second polarization beam splitter 204. The light intensity ratio is controlled at 1:1 to form an input beam for simulating an unknown quantum state. These two beams, as the unknown quantum state to be transmitted at the Cindy end, together with the H1 and V1 beams at the Alice end, participate in the subsequent joint measurement simulation.

[0044] The measurement module 30 is used to measure the polarized beams output from the Alice end, Bob end and Cindy end under multiple preset measurement bases, obtain the light intensity data of the polarized beams under multiple preset measurement bases, and transmit the light intensity data to the data processing module 40.

[0045] The measurement module 30 sets the measurement base for the input beams at the Alice end, Bob end, and Cindy end, respectively. It achieves projection measurement under multiple different measurement bases by changing the angle of the polarizer, and uses a photodetector to collect the output light intensity under each measurement base.

[0046] Among them, such as Figure 4 As shown, the measurement module 30 includes a polarizer 301 and a photodetector 302; the polarizer 301 and the photodetector 302 are arranged opposite to each other. The polarizer 301 is used to limit the polarized beam by the polarization angle to form a plurality of polarized beams under a preset measurement base, and the photodetector 302 is used to acquire the light intensity data of the polarized beam under each preset measurement base.

[0047] By adjusting the angle of polarizer 301, projection measurements of 16 measurement bases (where R measurement is replaced by rotating polarizer 301 by -45°) can be achieved. The 16 measurement bases include HH, HV, VH, VV, HD, HR, VD, VR, DH, DV, DD, DR, RH, RV, RD, and RR, covering all necessary polarization projection combinations.

[0048] In one example, the measurement module 30 further includes a third half-wave plate 303, which is disposed on the optical path of the polarizer 301 away from the photodetector 302. The third half-wave plate 303 is used to perform quantum gate operations by defining an angle.

[0049] The quantum gate operation is a Pauli X-gate, which is achieved by adjusting the angle of the third half-wave plate 303 to 45°. At this point, the Jones matrix of the third half-wave plate 303 is... The unitary transformation matrix is ​​completely consistent with that of the Pauli X gate. At this angle, the third half-wave plate 303 can flip the incident horizontally polarized light into vertically polarized light and vice versa, achieving an operation that is completely equivalent to the "bit flip" of the Pauli X gate.

[0050] In practical applications, it is also necessary to calibrate polarizer 301 and third half-wave plate 303 separately to determine the transmission direction and extinction ratio. The calibration of polarizer 301 is as follows: using the horizontally (H) polarized light transmitted through the polarizing beam splitter (PBS) as a standard, place the polarizer 301 under test into the optical path, ensuring the light path passes through the center of the device and is incident normally. Rotate polarizer 301 360°, and simultaneously record the transmitted light intensity data in real time using photodetector 302. From the recorded data, find the angle of polarizer 301 corresponding to the maximum light intensity; this angle is the transmission axis direction of polarizer 301. The extinction ratio is determined based on the ratio of the maximum to the minimum value, and the extinction ratio is required to be ≥100:1.

[0051] Similarly, the calibration of the third half-wave plate 303 is as follows: using the horizontal (H) polarized light transmitted through the polarization beam splitter (PBS) as the standard incident light, the half-wave plate to be tested is placed in the optical path, aligned with the center of the optical path, and the half-wave plate 303 is rotated 360°. At the same time, the transmitted light intensity data is recorded in real time by the photodetector 302. The half-wave plate angle corresponding to the maximum light intensity value is selected from the data. This angle is the direction of the optical axis of the half-wave plate (the transmitted light intensity is strongest when the optical axis is parallel to the incident H polarized light). The ratio of the maximum value to the minimum value is calculated to determine the extinction ratio, and the extinction ratio is required to be ≥100:1. If the standard is not met, the surface of the half-wave plate is cleaned or the component is replaced to ensure the accuracy of polarization state transformation.

[0052] Among them, the measurement modules 30 at the Alice, Bob, and Cindy ends are movable and reusable, while the remaining components are fixed to the optical platform and do not require disassembly or adjustment.

[0053] The data processing module 40 is used to receive the light intensity data from the measurement module 30, and convert the light intensity data into coincidence counts in combination with preset counting rules, and determine the optical path configuration for quantum entanglement state measurement and quantum teleportation based on the coincidence counts.

[0054] Among them, coincidence count is calculated based on the combination of measurement basis and light intensity data collected by the detector according to preset rules, and combined with quantum state tomography to verify whether the optical path configuration in the experimental device accurately simulates the quantum entangled state measurement and quantum teleportation process.

[0055] It should be noted that this embodiment uses classical optical components to construct an experimental device for simulating quantum entanglement measurement and quantum teleportation. The simulated entanglement light source module emits a first beam from a laser source, which is then polarized and split to generate two polarized optical paths for simulating the spatial separation of entangled photon pairs. These two polarized optical paths correspond to the output channels of the Alice and Bob ends, respectively. The simulated unknown quantum state generation module emits a second beam from a laser source, which is then polarized and split to generate two second polarized beams with mutually orthogonal polarization directions and equal intensity, used to simulate the generation of unknown quantum states. These two second polarized beams correspond to the output channels of the Cindy end. The output channel is used as the input source for the unknown polarization state to be measured. A measurement module is also built to measure the polarization beams output from the Alice, Bob, and Cindy ends under multiple preset measurement bases. The light intensity data of the polarization beams under multiple preset measurement bases are measured, and the light intensity data is converted into coincidence counts based on preset counting rules. The optical path configuration for quantum entanglement state measurement and quantum teleportation is determined based on the coincidence counts. Thus, the simulation experiment is realized using a classical light source. There is no quantum state decoherence problem. The experimental results are minimally affected by environmental interference, have high stability, and can accurately reproduce the mathematical logic and core characteristics of quantum entanglement and teleportation, with good repeatability.

[0056] In some embodiments, the data processing module 40 is used to calculate a first coincidence count based on the light intensity data at the Alice end and the Bob end, combined with a preset counting rule, determine the measured probability distribution of the reconstructed Bell state measurement based on the first coincidence count, and determine the fidelity based on the measured probability distribution and quantum state tomography, and determine whether the fidelity is greater than or equal to a preset fidelity threshold. If the fidelity is less than the preset fidelity threshold, the configuration parameters of the optical path elements in the experimental device are recalibrated until the fidelity is greater than or equal to the preset fidelity threshold, thereby obtaining the optical path configuration for simulating quantum entangled state measurement.

[0057] Among these, the coincidence counting rule allows the use of four polarized beams to simulate entangled photon pairs, and different target Bell states correspond to different coincidence counting rules. For example, the simulated target Bell state is... When using coincidence counting rules, the combination of general rules and special rules is included. The special rules apply to coincidence counting under the DR, RD, and RR measurement bases, while the general rules apply to coincidence counting under all other measurement bases besides the DR, RD, and RR measurement bases.

[0058] The general rule is: Consistency count = min(A0,B0) + min(A1,B1).

[0059] Where A0 is the light intensity measurement value of the photodetector 302 (corresponding to detector A0) at the Alice end that detects horizontally (H) polarized light, A1 is the light intensity measurement value of the photodetector 302 (corresponding to detector A1) at the Alice end that detects vertically (V) polarized light, min(A0,B0) is the smaller value between A0 and B0, B0 is the light intensity measurement value of the photodetector 302 (corresponding to detector B0) at the Bob end that detects horizontally (H) polarized light, B1 is the light intensity measurement value of the photodetector 302 (corresponding to detector B1) at the Bob end that detects vertically (V) polarized light; min(A1,B1) is the smaller value between A1 and B1, and the sum of the two is the coincidence count.

[0060] The special rules are: under DR / RD basis, the coincidence count = 1 / 2[min(A0,B0)+min(A1,B1)], and under RR basis, the coincidence count = |min(A0,B0)-min(A1,B1)|.

[0061] The data processing module 40 calculates the coincidence counts for each measurement basis based on the light intensity data from the Alice and Bob ends, combined with preset counting rules. It collects the coincidence counts of 16 measurement basis sets and calculates the ratio of each set's coincidence count to the sum of the coincidence counts of the four measurement basis sets (HH, HV, VH, and VV) to obtain the measured probability of reconstructing the Bell state for each measurement basis. Then, using quantum state tomography, the calculation relationship between the measured probability and fidelity is automatically executed in a Matlab program. The module inputs the 16 sets of coincidence counts, reconstructs the density matrix using maximum likelihood estimation, and then calculates the coincidence count with the target Bell state. To ensure the fidelity, a fidelity threshold of 0.9 is typically set. A simulation is considered successful when the fidelity is ≥0.9. Otherwise, the configuration parameters of the optical components within the experimental setup need to be recalibrated. For example, check that the beam splitter's splitting ratio is 50%:50% with an error ≤3%. If the light intensity is uneven, fine-tune the BS angle or replace with a qualified component to ensure equal intensity of the four polarized beams at the Alice / Bob end. Verify the polarization beam splitter (PBS) to ensure complete separation of H / V polarized light (extinction ratio ≥100:1). If separation is incomplete, clean the PBS surface or re-fix the installation angle. The calibration process can also be repeated to correct the polarizer 301, ensuring a transmission direction error ≤2° and an extinction ratio ≥100:1. The 16 measurement bases can also be checked one by one to ensure that the polarizer 301 angle error for each measurement base is ≤1°, etc., until the fidelity reaches 0.9 or higher.

[0062] It should be noted that quantum state tomography is a technique that reconstructs the complete mathematical description (density matrix) of a quantum state by projecting measurements of a quantum system under multiple different measurement bases. Based on the projection operator of the measurement base, the discrete coincidence count data is fitted into a complete density matrix by the least squares method or maximum likelihood estimation. By calculating the inner product of the measured density matrix and the target state density matrix, i.e., the fidelity, the degree of closeness between the reconstructed state and the ideal Bell state is determined.

[0063] In some embodiments, the data processing module 40 is used to calculate a second coincidence count based on the light intensity data of the Alice end and the Cindy end, combined with a preset counting rule, and to project the polarization state of the Alice end and the unknown polarization state of the Cindy end onto the target Bell state based on the second coincidence count; it is also used to determine the solution of the unknown polarization state of the Cindy end based on the light intensity data of the Bob end after the quantum gate operation.

[0064] In this context, based on the light intensity data from Alice and Cindy, the second coincidence counting rule also needs to be set according to the target Bell state of the projection. For example, the joint measurement projection of Alice and Cindy can be limited to... At that time, the coincidence count = min(C0,A1) + min(C1,A0), where C0 is the light intensity data of Cindy's end in the H polarization direction, and C1 is the light intensity data of Cindy's end in the V polarization direction. Based on the second coincidence count, the measured probability distribution of the reconstructed Bell state measurement is determined. According to this distribution, the polarization state of Alice's end and the unknown polarization state of Cindy's end are projected onto the target Bell state. Then, Alice's end informs Bob's end of the measurement result projected onto the target Bell state through a classical channel (such as verbal communication or written recording, which is not limited here), simulating the classical channel transmission process in quantum teleportation.

[0065] Based on the received measurement results, the Bob end selects the corresponding quantum gate operation sequence, adjusts the angle of the third half-wave plate 303 to 45°, making its Jones matrix consistent with the unitary transformation matrix of the Pauli X gate, thus achieving accurate recovery of the unknown polarization state at the Cindy end. The solution for the unknown polarization state at the Cindy end is calculated using the light intensity data from the Bob end after the quantum gate operation, i.e.:

[0066] ,

[0067] In the formula, , For the coefficient of the unknown polarization state at the Cindy end, The maximum light intensity value recorded by photodetector 302 when a horizontal (H) polarization measurement base is used at the Bob end. 1 is the maximum light intensity value recorded by photodetector 302 when the Bob end is measured using a vertical (V) polarization base.

[0068] Then, the solution for the unknown polarization state is expressed as: ,in, The solution is for an unknown polarization state. It is a horizontal (H) polarization state. It is a vertical (V) polarization state. That is, the unknown polarization state is a horizontal polarization state. and vertical polarization state The superposition state, with probability In horizontal polarization state probability In vertical polarization state .

[0069] Compare the solution of the unknown polarization state at the Cindy end with the preset polarization state at the Cindy end. If the solution of the unknown polarization state at the Cindy end is inconsistent with the preset polarization state at the Cindy end, then recalibrate the configuration parameters of the optical path elements in the experimental device until the solution of the unknown polarization state at the Cindy end is consistent with the preset polarization state at the Cindy end, and obtain the optical path configuration for simulating quantum teleportation.

[0070] Among them, the polarization state of the Cindy end can be preset (e.g., 45°), and the solution of the unknown polarization state of the Cindy end can be compared with the theoretical value of the preset 45° linear polarization state to verify the effect of the experimental device in simulating quantum teleportation.

[0071] If the solution for the unknown polarization state at the Cindy end is inconsistent with the preset polarization state at the Cindy end, the configuration parameters of the optical path elements in the experimental setup are recalibrated (refer to the aforementioned calibration method) until the solution for the unknown polarization state at the Cindy end is consistent with the preset polarization state at the Cindy end, thus obtaining the optical path configuration for simulating quantum teleportation.

[0072] In practical applications, the experimental setup proposed in this application is suitable for teaching experiments on quantum entanglement. Through a combination of classical light sources and polarization control elements, it intuitively presents the non-local correlation characteristics of entangled states and the teleportation process, effectively lowering the teaching threshold. By employing classical optical components, the cost is low, only 5% of that of traditional SPDC devices, making it suitable for bulk purchase. Through a measurement-calculation-verification closed loop, it helps students understand the basic concepts of quantum information technology and the basic process of quantum communication. There is no quantum state decoherence problem, and the experimental results are less affected by environmental interference (temperature, vibration, ambient light), making it suitable for classroom demonstrations and repeated teaching. Furthermore, through a special design conforming to counting rules and a half-wave plate quantum gate, the quantum state fidelity is ≥0.9, and the unknown state recovery error is ≤2%, accurately reproducing the mathematical logic and core characteristics of quantum entanglement and teleportation.

[0073] The following details the simulation of quantum entangled states using classical light sources. Examples of experimental procedures for measurement.

[0074] 1) Optical path setup: such as Figure 5 As shown, the laser source Lig1 outputs a visible light beam (e.g., 635nm). After the beam power is calibrated by the aperture Iris1 (2-5mm), it passes sequentially through the half-wave plate HWP1 and the polarization beam splitter PBS1, splitting the incident light into horizontally (H) polarized light and vertically (V) polarized light (intensity ratio ≈ 1:1). The two polarized beams are then incident on two 50%:50% beam splitters BS1 and BS2, respectively, each splitting into two beams, ultimately forming four polarized beams of equal power.

[0075] At the Alice end, the measurement module includes a polarizer PP1 and a photodetector Det A0. The polarizer PP1 can be rotated to select the measurement base, and works with the photodetector Det A0 to record light intensity data. Similarly, at the Alice end, the measurement module is multiplexed and includes a polarizer PP2 and a photodetector Det A1, which are used for the selection of the measurement base and the acquisition of light intensity for another path.

[0076] At the Bob end, the measurement module includes a polarizer PP3 and a photodetector Det B1. The polarizer PP3 can be rotated to select the measurement base, and works with the photodetector Det B1 to record the light intensity data under the corresponding base. The measurement module can also be reused. At the Bob end, the multiplexed measurement module includes a polarizer PP4 and a photodetector Det B0. The polarizer PP4 can also be rotated to switch the measurement base, and works with the photodetector Det B0 to record the light intensity under the corresponding base.

[0077] 2) Polarizer calibration:

[0078] Using the H-polarized light transmitted through the polarization beam splitter PBS1 as the standard light source, the polarizer to be tested (such as Alice end PP1) is placed in this optical path, the polarizer is rotated 360°, and the change in transmitted light intensity is recorded by a photodetector:

[0079] Light transmission direction: the polarizer angle corresponding to the maximum light intensity;

[0080] Extinction ratio: The ratio of the maximum value to the minimum value (required to be ≥100:1);

[0081] 3) Projection measurement:

[0082] The measurement base is switched by rotating the polarizer angle according to the preset 16 measurement bases (covering HH, HV, HD, HR, VH, VV, VD, VR, DH, DV, DD, DR, RH, RV, RD, RR). The light intensity data of each detector is recorded under each measurement base.

[0083] 4) Data processing and verification:

[0084] Calculate the coincidence count under each measurement base according to the counting rules, and then input it into the data processing module (such as a computer) to solve for the fidelity:

[0085] General measurement bases (such as HH, HV, DD, etc., 13 groups): coincidence count = min(A0,B0) + min(A1,B1);

[0086] Special measurement bases (DR, RD, RR 3 groups): under DR / RD base, coincidence count = 1 / 2 [min (A0,B0) + min (A1,B1)], under RR base, coincidence count = |min (A0,B0) - min (A1,B1)|; (min (A0,B0) means taking the minimum value between the measurements of A0 and B0, and the same applies to others).

[0087] The Matlab preset program that inputs the conformity count into the computer is used to calculate the quantum state fidelity using quantum state tomography to verify whether the target Bell state has been successfully simulated. The fidelity is required to be ≥0.9. If the fidelity meets the standard, it indicates that the system can effectively simulate the characteristics of entangled states.

[0088] Results verification: The theoretical projection probability of HH basis is 0.5, and the measured probability is 0.50; the theoretical projection probability of DD basis is 0.5, and the measured probability is 0.50; the theoretical projection probability of RR basis is 0, and the measured probability is 0.01. The error is ≤2%, and the fidelity is 0.9599. Figure 6 As shown.

[0089] The following details an example of an experiment simulating quantum teleportation using a classical light source.

[0090] 1) Optical path setup: such as Figure 7 As shown, in Figure 5Based on the optical path of the simulated quantum entangled state measurement, the Alice end and Bob end maintain the established quantum entangled channel without rebuilding. A new light source module is added at the Cindy end. In the light source module at the Cindy end, the laser light source Lig2 emits a 635nm beam, which is then power-adjusted by the aperture Iris2, and then passes through the half-wave plate HWP2 and the polarization beam splitter PBS2 to split the beam into horizontal (H) and vertical (V) polarization components, which are injected into the measurement module at the Cindy end respectively. The measurement module at the Cindy end includes a polarizer PP3 and a photodetector Det C0. After multiplexing, the measurement module includes a polarizer PP4 and a photodetector Det C1 for measurement basis selection and light intensity acquisition.

[0091] The Cindy terminal outputs an unknown quantum state (such as a 45° linearly polarized state). The polarizer is adjusted according to four measurement bases: HH, HV, VH, and VV. The light intensity data of the photodetectors Det C0 and Det C1 at the Cindy terminal and the photodetectors Det A0 and Det A1 at the Alice terminal are recorded. The coincidence count is calculated as "min (C0,A1) + min (C1,A0)".

[0092] Based on the data, the quantum states at the Alice and Cindy ends have been projected onto the target Bell state. .

[0093] 2) Alice communicates verbally or in writing that "the quantum states of Alice and Cindy have been projected onto the target Bell state." The Bell state measurement results are transmitted to Bob's end, simulating the classical channel in quantum teleportation.

[0094] 3) Half-wave plate calibration: Using the H-polarized light from the polarizing beam splitter PBS1 as the standard, rotate the half-wave plate 360° and record the maximum and minimum light intensity values ​​to determine the optical axis direction. The extinction ratio is ≥100:1.

[0095] Quantum gate manipulation: based on Alice's measurements (projected to...) Adjusting the half-wave plate angle to 45° makes it completely consistent with the unitary transformation matrix of the Pauli X gate, thus realizing quantum gate operation.

[0096] 4) Solving and verifying unknown states:

[0097] The light intensity data before and after the unitary transformation at the Bob end are shown in Table 1.

[0098] Table 1

[0099]

[0100] Solving for the unknown quantum state: Using the formula for the solution of the unknown polarization state, substituting the maximum light intensity after transformation (B0=0.36mW, B1=0.37mW), we calculate a≈0.71 and b≈0.70, determining that the unknown state at the Cindy end is a 45° linearly polarized state. The input is consistent with the actual input, thus completing the stealth transfer simulation.

[0101] Experimental results show that the system can accurately reconstruct the unknown quantum state initially prepared at the Cindy end, verifying the feasibility of remote quantum state reconstruction using unitary transformation based on a combination of classical and quantum channels. The entire process requires no direct interaction between physical particles; information transfer is completed solely through measurement correlation and feedback control, fully embodying the core concept of quantum teleportation.

[0102] Based on the same inventive concept, this application also provides an "experimental method for simulating quantum entangled state measurement and quantum teleportation using classical light sources" for implementing the "experimental apparatus for simulating quantum entangled state measurement and quantum teleportation using classical light sources" mentioned above.

[0103] The solution provided by this system is similar to the solution described in the above method. Therefore, the specific limitations of one or more experimental method embodiments for simulating quantum entangled state measurement and quantum teleportation with classical light sources provided below can be found in the limitations of the experimental apparatus for simulating quantum entangled state measurement and quantum teleportation with classical light sources described above, and will not be repeated here.

[0104] like Figure 8 As shown, this application provides an experimental method based on the experimental apparatus for simulating quantum entangled state measurement and quantum teleportation using a classical light source as described in the above embodiments, including:

[0105] Step S1: After the first beam is emitted by the first laser source, it undergoes polarization and beam splitting to generate two polarization optical paths for simulating entangled photon pairs separated in space. Each polarization optical path contains two first polarization beams with mutually orthogonal polarization directions and equal intensity. The two polarization optical paths correspond to the output channels of the Alice end and the Bob end, respectively.

[0106] Step S2: After the second beam is emitted by the second laser source, it undergoes polarization and beam splitting to generate two second polarized beams with mutually orthogonal polarization directions and equal intensity, which are used to simulate the generation of unknown quantum states. The two second polarized beams correspond to the output channels of the Cindy end.

[0107] Step S3: After measuring the polarized beams output from Alice, Bob and Cindy ends under multiple preset measurement bases, the light intensity data of the polarized beams under multiple preset measurement bases are obtained.

[0108] Step S4: Combine the preset counting rules to convert the light intensity data into coincidence counts, and determine the optical path configuration for quantum entanglement state measurement and quantum teleportation based on the coincidence counts.

[0109] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the method described above can be referred to the corresponding process in the foregoing device embodiments, and will not be repeated here.

[0110] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in sequences other than those illustrated or described herein.

[0111] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An experimental device for simulating quantum entangled state measurement and quantum teleportation with a classical light source, characterized in that, The application relates to a quantum entanglement simulation device and a quantum entanglement simulation method. The device comprises a simulated entangled light source module, a simulated unknown quantum state generation module, a measurement module and a data processing module. The simulated entangled light source module is used for generating two polarization light paths for simulating spatially separated entangled photon pairs through polarization and beam splitting processing of a first light beam emitted by a first laser light source, wherein each of the two polarization light paths comprises two first polarized beams with orthogonal polarization directions and equal intensity, and the two polarization light paths correspond to output channels of Alice and Bob respectively. The simulated unknown quantum state generation module is used for generating two second polarized beams with orthogonal polarization directions and equal intensity for simulating generation of unknown quantum states through polarization and beam splitting processing of a second light beam emitted by a second laser light source, and the two second polarized beams correspond to output channels of Cindy. The measurement module is used for measuring the polarization beams output by Alice, Bob and Cindy respectively under a plurality of preset measurement bases to obtain light intensity data of the polarization beams under the plurality of preset measurement bases, and transmitting the light intensity data to the data processing module. The data processing module is used for receiving the light intensity data of the measurement module, converting the light intensity data into coincidence counts in combination with a preset counting rule, and determining the light path configuration of quantum entanglement state measurement and quantum teleportation according to the coincidence counts.

2. The experimental setup for simulating quantum entangled state measurement and quantum teleportation with classical light sources according to claim 1, characterized in that, The simulated entangled light source module comprises a first laser light source, a first light diaphragm, a first half-wave plate, a first polarization beam splitter, a first beam splitter and a second beam splitter.

3. The experimental setup for simulating quantum entangled state measurement and quantum teleportation with classical light sources according to claim 1, characterized in that, The first laser light source emits a first light beam, the first light beam is adjusted in light intensity by the first light diaphragm, and then sequentially passes through the first half-wave plate and the first polarization beam splitter to generate a first horizontal polarization component and a first vertical polarization component.

4. The experimental setup for simulating quantum entangled state measurement and quantum teleportation with classical light sources according to claim 1, characterized in that, The first horizontal polarization component and the first vertical polarization component are split by the first beam splitter and the second beam splitter respectively to form two polarization light paths, wherein each of the two polarization light paths comprises two first polarized beams with orthogonal polarization directions and equal intensity.

5. The experimental setup for simulating quantum entangled state measurement and quantum teleportation with classical light sources according to claim 4, characterized in that, The simulated unknown quantum state generation module comprises a second laser light source, a second light diaphragm, a second half-wave plate and a second polarization beam splitter.

6. The experimental setup for simulating quantum entangled state measurement and quantum teleportation with classical light sources according to claim 5, characterized in that, The second light beam emitted by the second laser light source is adjusted in light intensity by the second light diaphragm, and then sequentially passes through the second half-wave plate and the second polarization beam splitter to be split into two second polarized beams with orthogonal polarization directions and equal intensity. The measurement module comprises a polarizer and a photodetector. The polarizer and the photodetector are oppositely arranged, the polarizer is used for forming polarization beams under a plurality of preset measurement bases by limiting the polarization angle of the polarization beams, and the photodetector is used for acquiring light intensity data of the polarization beams under each of the preset measurement bases. The measurement module further comprises a third half-wave plate arranged on a light path on a side of the polarizer away from the photodetector. The extinction ratios of the polarizer and the third half-wave plate are both greater than or equal to 100:

1.

7. The experimental setup for simulating quantum entangled state measurement and quantum teleportation with classical light sources according to claim 4, characterized in that, The data processing module is configured to calculate a first coincidence count according to the light intensity data of the Alice end and the Bob end in combination with the preset counting rule, determine a measured probability distribution of the restored Bell state measurement according to the first coincidence count, and determine a fidelity according to the measured probability distribution in combination with a quantum state tomography technique, judge whether the fidelity is greater than or equal to a preset fidelity threshold, if the fidelity is less than the preset fidelity threshold, recalibrate the configuration parameters of the optical path elements in the experimental device until the fidelity is greater than or equal to the preset fidelity threshold, and obtain the optical path configuration of the simulated quantum entangled state measurement.

8. The experimental setup for simulating quantum entangled state measurement and quantum teleportation with classical light source according to claim 4, characterized in that, The data processing module is configured to calculate a second coincidence count according to the light intensity data of the Alice end and the Cindy end in combination with the preset counting rule, project the polarization state of the Alice end and the unknown polarization state of the Cindy end to a target Bell state according to the second coincidence count, and determine the solution of the unknown polarization state of the Cindy end according to the light intensity data of the Bob end after the quantum gate operation. The consistency of the solution of the unknown polarization state of the Cindy end and the preset polarization state of the Cindy end is compared, if the solution of the unknown polarization state of the Cindy end is inconsistent with the preset polarization state of the Cindy end, the configuration parameters of the optical path elements in the experimental device are recalibrated until the solution of the unknown polarization state of the Cindy end is consistent with the preset polarization state of the Cindy end, and the optical path configuration of the simulated quantum teleportation is obtained.

9. The experimental setup for simulating quantum entangled state measurement and quantum teleportation with classical light sources according to claim 1, characterized in that, The splitting ratios of the first beam splitter and the second beam splitter are both 50%:50%.

10. An experimental method based on the experimental device for simulating quantum entangled state measurement and quantum teleportation with a classical light source according to any one of claims 1-9, characterized in that, Comprising: After the first light beam emitted by the first laser source is subjected to polarization and splitting processing, two polarization optical paths for simulating spatially separated entangled photon pairs are generated, wherein each of the polarization optical paths includes two first polarized beams with orthogonal polarization directions and equal intensities, and the two polarization optical paths correspond to the output channels of the Alice end and the Bob end, respectively; After the second light beam emitted by the second laser source is subjected to polarization and splitting processing, two second polarized beams with orthogonal polarization directions and equal intensities are generated for simulating the generation of unknown quantum states, and the two second polarized beams correspond to the output channels of the Cindy end; After the polarization beams output by the Alice end, the Bob end and the Cindy end are measured under a plurality of preset measurement bases, light intensity data of the polarization beams under the plurality of preset measurement bases are obtained; The light intensity data is converted into coincidence counts in combination with a preset counting rule, and the optical path configuration of quantum entangled state measurement and quantum teleportation is determined according to the coincidence counts.

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