Linear optical three-bit hypergraph state quantum combined measurement device and method
By using a linear optical three-qubit supergraph quantum joint measurement device, and by combining a beam splitter and a half-wave plate, stable and efficient measurement of multi-qubit supergraphs is achieved, filling the gap in multi-qubit supergraph-based quantum joint measurement and supporting the construction of distributed quantum networks and long-distance quantum cooperative manipulation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-11
- Publication Date
- 2026-03-13
AI Technical Summary
Research on multi-qubit supergraph-based quantum joint measurement is still lacking in current technologies, especially in the area of multi-qubit supergraph-based quantum joint measurement, which limits the development of multi-qubit quantum measurement technology and the construction of distributed quantum networks.
A linear optical three-qubit super-graph quantum joint measurement device is adopted. By combining a beam splitter module, a flipping module, an interference module, and a detection module, the three-qubit super-graph measurement of the quantum state encoded on three optical quantum polarization qubits is realized. By utilizing a specific combination of a beam splitter, a half-wave plate, and a polarization beam splitter, it is applicable to any input optical quantum polarization state and avoids the use of nonlinear media and auxiliary photons.
It achieves stable and efficient measurement of multi-qubit supergraphs, is applicable to multi-qubit quantum joint measurement problems in optical quantum information processing, supports long-distance quantum cooperative manipulation, adapts to the long-distance transmission characteristics of photons, and promotes the development of quantum information technology and network technology.
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Figure CN121655683A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of quantum measurement technology, and in particular to a linear optical three-qubit supergraph quantum joint measurement device and method. Background Technology
[0002] In recent years, quantum information technology has developed rapidly, especially in the field of quantum computing. Superconducting and optical quantum systems have achieved quantum superiority over classical computers, fully demonstrating the enormous potential of this technology.
[0003] With technological iteration, network collaboration among quantum information processors is becoming a key direction in quantum information research. On the one hand, distributed quantum computing architectures connect multiple high-performance, finite-scale processor modules through classical and quantum channels, enabling coherent sharing, transmission, and collaborative operation of quantum states and quantum logic gates between modules over long distances. This is widely recognized as a feasible path for the large-scale development of quantum computing. On the other hand, network collaboration can not only inspire entirely new quantum tasks but also expand the boundaries of technological applications, catalyzing disruptive changes. In this process, photons, as the core carrier of quantum networks, are currently the only "flying qubits" capable of long-distance coherent transmission. Their irreplaceable transmission characteristics become the core support for the large-scale evolution of optical quantum networks.
[0004] Quantum joint measurement is a key component for the functionality of optical quantum networks. Mathematically, quantum measurement is described by Hermitian operators, and its entanglement property is determined by the properties of eigenstates. A measurement possesses entanglement properties when the set of eigenstates of the multi-particle quantum joint measurement operator contains at least one entangled state. This entangled quantum joint measurement is not only a fundamental step in extracting quantum information but also a core means of stimulating multi-qubit quantum entanglement and constructing large-scale quantum networks.
[0005] However, current research on quantum joint measurement has significant limitations, focusing primarily on two-qubit Bell measurements and multi-qubit GHZ state basis measurements. Research on quantum joint measurement of multi-qubit supergraph basis states remains a gap that urgently needs to be filled. On the one hand, supergraph states, with their complex entangled structures, demonstrate enormous application potential in quantum information processing tasks; on the other hand, quantum joint measurement of multi-qubit supergraph basis states is itself a core technological component for realizing multi-qubit distributed quantum gates.
[0006] Therefore, the development of a linear optical three-qubit supergraph quantum joint measurement device is of great significance: it can fill the research gap in supergraph basis measurement and open up a new direction for the innovative development of multi-qubit quantum measurement technology; in addition, the linear optical three-qubit supergraph quantum joint measurement device can be adapted to the long-distance transmission characteristics of photons and can be directly integrated into the distributed optical quantum network architecture, providing key support for long-distance quantum collaborative manipulation, and playing an important role in promoting the continuous development of quantum information technology and quantum network technology. Summary of the Invention
[0007] To solve the above-mentioned technical problems, or at least partially solve them, the present invention provides a linear optical three-qubit supergraph quantum joint measurement device and method.
[0008] In a first aspect, the present invention provides a linear optical three-qubit super-graphical quantum joint measurement device, the device comprising: The beam splitting module is used to split the target photons according to their polarization states. The first bit flipping module is used to flip the polarization state of the second control photon; A first interference module is used to enable the second control photon from the first bit-flipping module and the target photon from the beam-splitting module to interact. The second bit-flipping module is used to flip the polarization state of photons from the first interference module; The second interference module is used to enable the incoming first control photon and the target photon from the first interference module to interact; A beam combining module is used to combine target photons from the second interference module; The first detection module is used to detect the first control photon from the second interference module. Basis vector projection measurement; The second detection module is used to detect the second control photon from the second bit-flipping module. Basis vector projection measurement; The third detection module is used to detect the target photons from the beam combining module. Basis vector projection measurement.
[0009] Optionally, the beam splitter module includes: The first beam splitter transmits the horizontal polarization component of the target photon and reflects the vertical polarization component of the target photon, so that the two polarization components of the target photon are separated into different paths.
[0010] Optionally, the first bit-flipping module includes: The first half-wave plate, with a rotation angle of 45°, is used to perform a single-bit X-gate operation on the second control photon passing through it. To complete the calculation of basis vectors and Switching between them.
[0011] Optionally, the second bit-flipping module includes: The second half-wave plate, with a rotation angle of 45°, is used to perform a single-bit X-gate operation on photons passing through it. To complete the calculation of basis vectors and Switching between them.
[0012] Optionally, the first interference module includes: The third half-wave plate, the fourth half-wave plate, the first type of polarization-dependent beamsplitter, the first and second types of polarization-dependent beamsplitter, the second and third types of polarization-dependent beamsplitter, and the third and second types of polarization-dependent beamsplitter. The rotation angle of the third and fourth half-wave plates is 22.5°. The third half-wave plate is used to perform single-bit processing on the photons passing through it. Door operation To complete the calculation of the basis vectors { } and diagonal basis vectors { Switching between}, where , The fourth half-wave plate is used to perform single-bit processing on photons passing through it. Door operation To complete the calculation of the basis vectors { } and diagonal basis vectors { Switching between}, where ; The first type of polarization-dependent beam splitter fully transmits horizontally polarized light, has a transmittance of 1 / 3 for vertically polarized light, and a reflectance of 2 / 3 for vertically polarized light, introducing the vertically polarized component into the reflected light. Phase, The second type of polarization-dependent beam splitter fully transmits vertically polarized light, has a transmittance of 1 / 3 for horizontally polarized light, and a reflectance of 2 / 3 for horizontally polarized light.
[0013] Optionally, the second interference module includes: The second type of polarization-dependent beam splitter, the fourth type of polarization-dependent beam splitter, the fifth type of polarization-dependent beam splitter, and the sixth type of polarization-dependent beam splitter. The first type of polarization-dependent beam splitter fully transmits horizontally polarized light, has a transmittance of 1 / 3 for vertically polarized light, a reflectance of 2 / 3 for vertically polarized light, and introduces the vertically polarized component of the reflected light. Phase, The second type of polarization-dependent beam splitter fully transmits vertically polarized light, has a transmittance of 1 / 3 for horizontally polarized light, and a reflectance of 2 / 3 for horizontally polarized light.
[0014] Optionally, the beam combining module includes: The fifth half-wave plate, with a rotation angle of 22.5°, is used to process single qubits of photons passing through it. Door operation To complete the calculation of the basis vectors { } and diagonal basis vectors { Switching between}, where ; Second beam splitter; The sixth half-wave plate, with a rotation angle of 45°, is used to implement single-bit X-gate operation of photons passing through it. To complete the calculation of basis vectors and Switching between them.
[0015] Optionally, the first detection module includes: The seventh half-wave plate, wherein the rotation angle of the seventh half-wave plate is 22.5°, First and third types of polarization beam splitters; The first and second single-photon detectors are used to convert the received photons into electrical pulse signals and then output them. The third type of polarization beam splitter transmits the horizontal polarization component of the incoming photons and reflects the vertical polarization component.
[0016] Optionally, the second detection module includes: The eighth half-wave plate, wherein the rotation angle of the eighth half-wave plate is 22.5°, Second and third types of polarization beam splitters; The third and fourth single-photon detectors are used to convert the received photons into electrical pulse signals for output. The third type of polarization beam splitter transmits the horizontal polarization component of the incoming photons and reflects the vertical polarization component.
[0017] Secondly, a linear optical three-qubit hypergraph quantum joint measurement method is provided, which uses the linear optical three-qubit hypergraph quantum joint measurement device as described in any of the preceding claims.
[0018] This invention provides a linear optical three-qubit hypergraph quantum joint measurement device and method. The device includes: a beam-splitting module for splitting target photons according to their polarization states; a first qubit-flipping module for flipping the polarization state of a second control photon; a first interference module for enabling the second control photon from the first qubit-flipping module and the target photon from the beam-splitting module to interact; a second qubit-flipping module for flipping the polarization state of a photon from the first interference module; a second interference module for enabling the incoming first control photon and the target photon from the first interference module to interact; a beam-combining module for combining the target photons from the second interference module; and a first detection module for detecting the first control photon from the second interference module. Basis vector projection measurement; a second detection module for detecting the second control photon from the second bit-flipping module. Basis vector projection measurement; a third detection module, used to detect the target photons from the beam combining module. Basis vector projection measurement. The device in this embodiment of the invention, through a specific combination of beam splitter BD, half-wave plate HWP, and polarization beam splitters PDBS1, PDBS2, and PBS, realizes three-qubit super-graph state measurement of quantum states encoded on three optical quantum polarization qubits in a spatial optical path. This invention does not require a nonlinear medium or the introduction of auxiliary photons, is applicable to any input optical quantum polarization state, exhibits high stability and fast execution speed, and is suitable for solving multi-qubit quantum joint measurement problems in optical quantum information processing. Attached Figure Description
[0019] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.
[0020] 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, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0021] Figure 1 The diagram shown is a schematic representation of the linear optical three-qubit hypergraph quantum joint measurement device according to an embodiment of the present invention. Figure 2 The diagram shown is a quantum circuit diagram of a three-qubit hypergraph quantum joint measurement according to an embodiment of the present invention; The following modules are included: 1. Beam splitting module; 2. First bit flipping module; 3. First interference module; 4. Second bit flipping module; 5. Second interference module; 6. Beam combining module; 7. First detection module; 8. Second detection module; 9. Third detection module; 101. First beam splitter; 201. First half-wave plate; 301. Third half-wave plate; 306. Fourth half-wave plate; 302. First polarization-dependent beam splitter; 303. First polarization-dependent beam splitter; 304. Second polarization-dependent beam splitter; 305. Third polarization-dependent beam splitter; 401. Second half-wave plate; 501. Second polarization-dependent beam splitter; 502. Fourth half-wave plate; 503. First polarization-dependent beam splitter; 504. Second polarization-dependent beam splitter; 505. Third polarization-dependent beam splitter; 401. Second half-wave plate; 501. Second polarization-dependent beam splitter; 502. Fourth half-wave plate; 201. First half-wave plate; 202. Second half-wave plate; 203. First half-wave plate; 204. Second half-wave plate; 205. Third half-wave plate; 206. Fourth half-wave plate; 202. First half-wave plate; 203. Second ...7. First half-wave plate; 208. Second half-wave plate; 209. Second half-wave plate; 2000. Second half-wave plate; Two types of polarization-dependent beamsplitters; 503, the fifth type of second polarization-dependent beamsplitter; 504, the sixth type of second polarization-dependent beamsplitter; 601, the fifth half-wave plate; 602, the second beamsplitter; 603, the sixth half-wave plate; 701, the seventh half-wave plate; 702, the first and third type of polarization beamsplitters; 703, the first single-photon detector; 704, the second single-photon detector; 801, the eighth half-wave plate; 802, the second and third type of polarization beamsplitters; 803, the third single-photon detector; 804, the fourth single-photon detector; 901, the ninth half-wave plate; 902, the third type of polarization beamsplitter; 903, the fifth single-photon detector; 904, the sixth single-photon detector. Detailed Implementation
[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, 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.
[0023] Figure 1 The diagram shown is a schematic representation of the linear optical three-qubit hypergraph quantum joint measurement device according to an embodiment of the present invention. Figure 2 The diagram shown is a quantum circuit diagram in the linear optical three-qubit hypergraph quantum joint measurement device according to an embodiment of the present invention.
[0024] refer to Figure 1 , Figure 2 As shown, the apparatus of this embodiment includes: Beam splitting module 1 is used to split the target photons according to their polarization states; The first bit-flipping module 2 is used to flip the polarization state of the second control photon; The first interference module 3 is used to enable the second control photon from the first bit-flipping module 2 and the target photon from the beam-splitting module 1 to interact. The second bit-flipping module 4 is used to flip the polarization state of photons from the first interference module 3; The second interference module 5 is used to enable the incoming first control photon and the target photon from the first interference module 3 to interact. The beam combining module 6 is used to combine photons from the second interference module 5. The first detection module 7 is used to detect the first control photon from the second interference module 5. Basis vector projection measurement; The second detection module 8 is used to detect the second control photon from the second bit-flipping module 4. Basis vector projection measurement; The third detection module 9 is used to detect the target photons from the beam combining module 6. Basis vector projection measurement.
[0025] In this embodiment of the invention, the beam splitting module 1 includes: The first beam splitter 101 (BD) is used to transmit the horizontal polarization component of the target photon and reflect the vertical polarization component of the target photon, so that the two polarization components of the target photon are separated into different paths.
[0026] In this embodiment of the invention, the first bit-flipping module 2 includes: The first half-wave plate 201 (HWP) has a rotation angle of 45° and is used to perform a single-bit X-gate operation on the second control photon passing through it. To complete the calculation of basis vectors and Switching between them.
[0027] In this embodiment of the invention, the second bit-flipping module 4 includes: The second half-wave plate 401, with a rotation angle of 45°, is used to perform a single-bit X-gate operation on photons passing through it. To complete the calculation of basis vectors and Switching between them.
[0028] In this embodiment of the invention, the first interference module 3 includes: The third half-wave plate 301, the fourth half-wave plate 306, the first type of polarization-dependent beam splitter 302 (PDBS), the first type of polarization-dependent beam splitter 303, the second type of polarization-dependent beam splitter 304, and the third type of polarization-dependent beam splitter 305. The rotation angle of the third half-wave plate 301 and the fourth half-wave plate 306 is 22.5°. The third half-wave plate 301 is used to perform single-bit processing on photons passing through the third half-wave plate 301. Door operation To complete the calculation of the basis vectors { } and diagonal basis vectors { Switching between}, where , The fourth half-wave plate 306 is used to perform single-bit processing on photons passing through the fourth half-wave plate 306. Door operation To complete the calculation of the basis vectors { } and diagonal basis vectors { Switching between}, where ; The first type of polarization-dependent beam splitter fully transmits horizontally polarized light, has a transmittance of 1 / 3 for vertically polarized light, and a reflectance of 2 / 3 for vertically polarized light, introducing the vertically polarized component into the reflected light. Phase, The second type of polarization-dependent beam splitter fully transmits vertically polarized light, has a transmittance of 1 / 3 for horizontally polarized light, and a reflectance of 2 / 3 for horizontally polarized light.
[0029] In this embodiment of the invention, the second interference module 5 includes: The second type of polarization-dependent beam splitter 501, the fourth type of polarization-dependent beam splitter 502, the fifth type of polarization-dependent beam splitter 503, and the sixth type of polarization-dependent beam splitter 504. The first type of polarization-dependent beam splitter fully transmits horizontally polarized light, has a transmittance of 1 / 3 for vertically polarized light, a reflectance of 2 / 3 for vertically polarized light, and introduces the vertically polarized component of the reflected light. Phase, The second type of polarization-dependent beam splitter fully transmits vertically polarized light, has a transmittance of 1 / 3 for horizontally polarized light, and a reflectance of 2 / 3 for horizontally polarized light.
[0030] In this embodiment of the invention, the beam combining module 6 includes: A fifth half-wave plate 601, with a rotation angle of 22.5°, is used to process single bits of photons passing through it. Door operation To complete the calculation of the basis vectors { } and diagonal basis vectors { Switching between}, where ; Second beam splitter 602; The sixth half-wave plate 603, with a rotation angle of 45°, is used to implement single-bit X-gate operation of photons passing through it. To complete the calculation of basis vectors and Switching between them.
[0031] In this embodiment of the invention, the first detection module 7 includes: The seventh half-wave plate 701 has a rotation angle of 22.5°. First and third type polarization beam splitter 702; The first single-photon detector 703 (SPD) and the second single-photon detector 704 are used to convert the received photons into electrical pulse signals and output them. The third type of polarization beam splitter (PBS) transmits the horizontal polarization component of the incoming photons and reflects the vertical polarization component.
[0032] In this embodiment of the invention, the computational ground state of three qubits is represented as follows: ,in Indicates the first The computational ground state of 1 qubit.
[0033] Toffoli Also known as a control-control-NOT gate, when both control bits are 0. At that time, the target bit is flipped, that is , The calculation of the basis vectors for the other three bits remains unchanged.
[0034] In this embodiment of the invention, there are eight complete orthogonal three-bit hypergraph states involved, and they are defined as follows: They are respectively in, It is a three-bit decimal representation of the ground state; It is a three-bit control Gate, when both control qubits are At that time, the target qubit is phase-flipped, that is... The calculation of the basis vectors for the other three bits remains unchanged; It is a single-bit Hadamard gate operation. Complete the calculation of basis vectors { } and diagonal basis vectors { Switching between}, where .
[0035] Please refer to the quantum circuit diagram for three-qubit hypergraph measurement. Figure 2 As shown, it contains a three-bit control Z-gate. 3 single-bit Hadamard gate operations Three single-bit calculations were used to determine the ground state measurement, and the measurement results were as follows: This means that the three-bit super-graph entering the measuring device is .
[0036] The following describes the specific method for realizing linear optical three-qubit super-graphical quantum joint measurement according to the present invention. Please refer to... Figure 1 and Figure 2 As shown. Quantum states are encoded in the polarization dimension of photons, and three photons can be in any quantum state. ,in and These represent the horizontal polarization components of the photon. and vertical polarization components ,coefficient It satisfies probability conservation The probability amplitude.
[0037] In this embodiment of the invention, the beam splitting module 1 is used to split the target photons according to their polarization states, such as... Figure 2 c and d in the example.
[0038] In this embodiment of the invention, the first control photon enters the measurement device through the second interference module 5, and the second control photon enters the measurement device through the first bit flipping module 2.
[0039] Figure 2 In the middle, using letters a The straight lines indicated represent the path of photon propagation. a ,letter b The straight lines indicated represent the path of photon propagation. b ,letter c The straight lines indicated represent the path of photon propagation. c ,letter d The straight lines indicated represent the path of photon propagation. d .
[0040] a represents the path of the first control photon, b represents the path of the second control photon, c represents the path of the horizontally polarized component in the target photon, and d represents the path of the vertically polarized component in the target photon.
[0041] In this embodiment of the invention, the first beam splitter 101 is formed by bonding a polarization beam splitter and a reflector. The horizontal polarization component of the target photon is transmitted and travels along the path. c Propagation, the vertically polarized component is reflected and travels along the path d Propagation. Therefore, the two polarization components of the target photon are separated into different paths, input quantum state. It is also divided into two parts, namely (labeled as the first part of the quantum state) and (Labeled as the second part of the quantum state), each part also has a different evolution / path in this device, where the subscripts are... a, b, c, d These represent the photon propagation paths.
[0042] In this embodiment of the invention, the first control photon enters the measuring device through the second interference module 5, and passes through the beam combining module 6 and the first detection module 7. The first control photon does not pass through other functional modules of the measuring device. However, since this embodiment of the invention includes three photons, and the output state is also related to these three photons, the quantum state of the target photon is described in the form of three photons / photon paths, such as a part of the first quantum state mentioned above. The beam splitter 101 includes three photon propagation paths: a, b, and c. However, in reality, there are no paths for the first control photon and the second control photon in the first beam splitter 101. There are only two paths for the target photon. Since the target photon is split into two paths according to its polarization state, these two paths do not overlap and will have different evolutions / paths in the future. Therefore, these two paths will not appear in the same quantum state.
[0043] In this embodiment of the invention, the first bit-flipping module 2 includes a 45° half-wave plate (HWP), which can realize single-bit flipping of incoming photons. X Door operation Complete the calculation of basis vectors and The switching between the two quantum states. The first and second quantum states in the device evolve into... and .
[0044] The first interference module 3 includes a third half-wave plate 301, a fourth half-wave plate 306, a first polarization-dependent beam splitter 302, a first second polarization-dependent beam splitter 303, a second second polarization-dependent beam splitter 304, and a third second polarization-dependent beam splitter 305.
[0045] When the first part of the quantum state passes through the first interference module 3, only the portion transmitted through each element is retained. The evolution process is as follows: When the second part of the quantum state passes through the first interference module 3, the post-selection technique retains only two paths. b and d When both have photons, the evolution process is as follows: The first interference module 3 only retains the first part of the quantum state and the second part of the quantum state. It did not change the first part of the quantum state, but it implemented a controlled NOT gate operation with the second control photon as the control bit and the target photon as the target bit in the second part of the quantum state.
[0046] The second interference module 5 includes a second polarization-dependent beamsplitter 501, a fourth polarization-dependent beamsplitter 502, a fifth polarization-dependent beamsplitter 503, and a sixth polarization-dependent beamsplitter 504. When the first part of the quantum state passes through the second interference module 5, only the portion transmitted through each element is retained. The evolution process is as follows: After the second part of the quantum state passes through the second interference module 5, the selection technique retains only two paths. a and d When both have photons, the evolution process is as follows: The second interference module 5 also only retained the first and second parts of the quantum state. The first part of the quantum state was not changed, but control was achieved in the second part of the quantum state, with the first control photon acting as the control bit and the target photon acting as the target bit. Z Door operation.
[0047] The fifth half-wave plate 601 in the beam combining module 6 has a rotation angle of 22.5°. The fifth half-wave plate 601 is used to combine single bits of photons passing through it. Door operation To complete the calculation of the basis vectors { } and diagonal basis vectors { Switching between}, where ; Second beam splitter 602; The sixth half-wave plate 603, with a rotation angle of 45°, is used to implement single-bit X-gate operation of photons passing through it. To complete the calculation of basis vectors and Switching between them.
[0048] When the first part of the quantum state passes through the second beam splitter 602, only the vertically polarized portion of the target photon is retained. The evolution process is as follows: When the second part of the quantum state passes through the second beam splitter 602, only the horizontal polarization portion of the target photon is retained. The evolution process is as follows: The beam combining module 6 also retained only the first and second part quantum states. The first part of the quantum state remains unchanged, but a controlled NOT gate operation is implemented in the second part of the quantum state, with the second control photon as the control bit and the target photon as the target bit. At this point, the two parts of the quantum state are recombined into a single quantum state. .
[0049] The second bit flipping module 4 contains a 45° half-wave plate HWP to achieve single-bit flipping. X Gate operation, quantum state is transformed .
[0050] Therefore, the above functional modules are in response to the input quantum state. The success rate is achieved as follows: Three-bit control Z Door .
[0051] The first detection module 7, the second detection module 8, and the third detection module 9 each contain a half-wave plate (HWP) with a rotation angle of 22.5°, a third polarization beam splitter (PBS), and two single-photon detectors (SPDs).
[0052] The first detection module 7 includes: The seventh half-wave plate 701 has a rotation angle of 22.5°. First and third type polarization beam splitter 702; The first single-photon detector 703 and the second single-photon detector 704 are used to convert the received photons into electrical pulse signals and then output them. The third type of polarization beam splitter transmits the horizontal polarization component of the incoming photons and reflects the vertical polarization component.
[0053] The second detection module 8 includes: The eighth half-wave plate 801 has a rotation angle of 22.5°. The second and third polarization beam splitters 802; The third single-photon detector 803 and the fourth single-photon detector 804 are used to convert the received photons into electrical pulse signals and then output them. The third type of polarization beam splitter transmits the horizontal polarization component of the incoming photons and reflects the vertical polarization component.
[0054] The third detection module 9 includes: a ninth half-wave plate 901 with a rotation angle of 22.5°, a third type of polarization beam splitter 902, a fifth single-photon detector 903, and a sixth single-photon detector 904; The functions of the second detection module 8 and the third detection module 9 are the same as those of the first detection module 7 described above, and will not be repeated here.
[0055] The first detection module 7, the second detection module 8, and the third detection module 9 respectively perform detection on the first control photon, the second control photon, and the target photon. Basis vector projection measurement. Therefore, ( The state is transformed after passing through a 22.5° half-wave plate. ( After passing through a third type of polarization beam splitter, the single-photon detector (SPD) reaches the transmission (reflection) end.
[0056] The transformations of the eight orthogonally complete three-bit hypergraph states through the above device can be summarized as follows: , , , , , , , .
[0057] When the measurement result of the first control photon is 0 (1), detector D1 (D2) responds; when the measurement result of the second control photon is 0 (1), detector D3 (D4) responds; when the measurement result of the target photon is 0 (1), detector D5 (D6) responds. Therefore, the simultaneous response of detectors D1, D3, and D5 means that the input state is Simultaneous response of detectors D1, D3, and D6 means that the input state is The simultaneous response of detectors D1, D4, and D5 means that the input state is The simultaneous response of detectors D1, D4, and D6 means that the input state is The simultaneous response of detectors D2, D3, and D5 means that the input state is The simultaneous response of detectors D2, D3, and D6 means that the input state is The simultaneous response of detectors D2, D4, and D5 means that the input state is The simultaneous response of detectors D2, D4, and D6 means that the input state is .
[0058] In summary, this invention discloses a polarization-encoded linear optical three-qubit super-graph quantum joint measurement device. Through a specific combination of beam splitter BD, half-wave plate HWP, polarization beam splitter PDBS1, PDBS2, and PBS, three-qubit super-graph measurement of quantum states encoded on three optical quantum polarization qubits is realized in the spatial optical path.
[0059] This invention also provides a linear optical three-qubit hypergraph quantum joint measurement method, which uses the linear optical three-qubit hypergraph quantum joint measurement device described above.
[0060] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0061] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.
Claims
1. A linear optical three-qubit hypergraph quantum joint measurement device, characterized in that, The device includes: The beam splitting module is used to split the target photons according to their polarization states. The first bit flipping module is used to flip the polarization state of the second control photon; A first interference module is used to enable the second control photon from the first bit-flipping module and the target photon from the beam-splitting module to interact. The second bit-flipping module is used to flip the polarization state of photons from the first interference module; The second interference module is used to enable the incoming first control photon and the target photon from the first interference module to interact; A beam combining module is used to combine target photons from the second interference module; The first detection module is used to detect the first control photon from the second interference module. Basis vector projection measurement; The second detection module is used to detect the second control photon from the second bit-flipping module. Basis vector projection measurement; The third detection module is used to detect the target photons from the beam combining module. Basis vector projection measurement.
2. The measuring device according to claim 1, characterized in that, The beam splitting module includes: The first beam splitter transmits the horizontal polarization component of the target photon and reflects the vertical polarization component of the target photon, so that the two polarization components of the target photon are separated into different paths.
3. The measuring device according to claim 1, characterized in that, The first bit-flipping module includes: The first half-wave plate, with a rotation angle of 45°, is used to perform a single-bit X-gate operation on the second control photon passing through it. To complete the calculation of basis vectors and Switching between them.
4. The measuring device according to claim 1, characterized in that, The second bit-flipping module includes: The second half-wave plate, with a rotation angle of 45°, is used to perform a single-bit X-gate operation on photons passing through it. To complete the calculation of basis vectors and Switching between them.
5. The measuring device according to claim 1, characterized in that, The first interference module includes: The third half-wave plate, the fourth half-wave plate, the first type of polarization-dependent beamsplitter, the first and second types of polarization-dependent beamsplitter, the second and third types of polarization-dependent beamsplitter, and the third and second types of polarization-dependent beamsplitter. The rotation angle of the third and fourth half-wave plates is 22.5°. The third half-wave plate is used to perform single-bit processing on the photons passing through it. Door operation To complete the calculation of the basis vectors { } and diagonal basis vectors { Switching between}, where , The fourth half-wave plate is used to perform single-bit processing on photons passing through it. Door operation To complete the calculation of the basis vectors { } and diagonal basis vectors { Switching between}, where ; The first type of polarization-dependent beam splitter fully transmits horizontally polarized light, has a transmittance of 1 / 3 for vertically polarized light, and a reflectance of 2 / 3 for vertically polarized light, introducing the vertically polarized component into the reflected light. Phase; The second type of polarization-dependent beam splitter fully transmits vertically polarized light, has a transmittance of 1 / 3 for horizontally polarized light, and a reflectance of 2 / 3 for horizontally polarized light.
6. The measuring device according to claim 1, characterized in that, The second interference module includes: The second type of polarization-dependent beam splitter, the fourth type of polarization-dependent beam splitter, the fifth type of polarization-dependent beam splitter, and the sixth type of polarization-dependent beam splitter. The first type of polarization-dependent beam splitter fully transmits horizontally polarized light, has a transmittance of 1 / 3 for vertically polarized light, a reflectance of 2 / 3 for vertically polarized light, and introduces the vertically polarized component of the reflected light. Phase; The second type of polarization-dependent beam splitter fully transmits vertically polarized light, has a transmittance of 1 / 3 for horizontally polarized light, and a reflectance of 2 / 3 for horizontally polarized light.
7. The measuring device according to claim 1, characterized in that, The beam combining module includes: The fifth half-wave plate, with a rotation angle of 22.5°, is used to process single qubits of photons passing through it. Door operation To complete the calculation of the basis vectors { } and diagonal basis vectors { Switching between}, where ; Second beam splitter; The sixth half-wave plate, with a rotation angle of 45°, is used to implement single-bit X-gate operation of photons passing through it. To complete the calculation of basis vectors and Switching between them.
8. The measuring device according to claim 1, characterized in that, The first detection module includes: The seventh half-wave plate, wherein the rotation angle of the seventh half-wave plate is 22.5°, First and third types of polarization beam splitters; The first and second single-photon detectors are used to convert the received photons into electrical pulse signals and then output them. The third type of polarization beam splitter transmits the horizontal polarization component of the incoming photons and reflects the vertical polarization component.
9. The measuring device according to claim 1, characterized in that, The second detection module includes: The eighth half-wave plate, wherein the rotation angle of the eighth half-wave plate is 22.5°, Second and third types of polarization beam splitters; The third and fourth single-photon detectors are used to convert the received photons into electrical pulse signals for output. The third type of polarization beam splitter transmits the horizontal polarization component of the incoming photons and reflects the vertical polarization component.
10. A linear optical three-qubit supergraph quantum joint measurement method, characterized in that, The linear optical three-qubit hypergraph quantum joint measurement device as described in any one of claims 1 to 9 is applied.