Microwave continuous variable quantum teleportation method and system

Abstract

The invention discloses a microwave continuous variable quantum teleportation method, which comprises the following steps that: a third party adopts a Josephh parametric amplifier and a microwave beam splitter to generate a dual-mode compression state in a set low-temperature environment, and sends the dual-mode compression state to a communication sender and a communication receiver; after receiving the signal, the communication sender performs Bell measurement to generate a feed-forward signal, and sends the feed-forward signal to the communication receiver; and the communication receiver processes the signal sent by the third party according to the received feedforward signal to obtain the quantum state sent by the communication sender, and microwave continuous variable quantum teleportation is completed. The invention also discloses a system for realizing the microwave continuous variable quantum teleportation method. Through the innovative design of the continuous variable quantum teleportation scheme and the innovative signal processing mode, microwave continuous variable quantum teleportation is achieved, reliability is better, and accuracy is better.

Description

Technical Field

[0001] This invention belongs to the field of quantum communication technology, specifically relating to a microwave continuous variable quantum teleportation method and system. Background Technology

[0002] Quantum teleportation (QT) is a rapidly developing new technology in recent years. It enables the transmission of an unknown quantum state from sender to receiver without direct transmission. QT allows the use of quantum entanglement and classical communication as resources to achieve the invisible and secure transmission of unknown quantum states.

[0003] Quantum teleportation was first proposed for discrete-variable quantum states, but subsequent research has also focused on continuous-variable quantum states. Quantum teleportation can be realized using either single-photon signals or continuous-variable signals. Schemes based on single-photon signals typically involve discrete quantum states: often using discrete qubits (e.g., spin), or discrete two-level systems like qubits; this technique is called discrete-variable quantum teleportation (DVQT). Schemes based on continuous-variable signals typically use continuous physical quantities (e.g., position and momentum); this may involve quantum states with continuous spectra, such as coherent states of a light field; this technique is called continuous-variable quantum teleportation (CVQT).

[0004] Continuous-variable quantum teleportation possesses high-dimensionality properties because continuous variables typically have infinite dimensions. Therefore, continuous-variable quantum teleportation may allow for the processing of higher-dimensional information. Moreover, in certain applications, continuous-variable quantum teleportation may be more efficient in terms of resource utilization.

[0005] Experiments demonstrating the feasibility of continuous-variable quantum teleportation at optical frequencies have been proven. Meanwhile, recent advances in superconducting quantum computing have spurred the need for quantum communication between spatially separated superconducting processors operating at microwave frequencies. Microwave continuous-variable quantum teleportation, due to its inherent frequency and technological compatibility with superconducting quantum computers, exhibits great potential and also offers the possibility of achieving unconditionally secure communication.

[0006] However, current microwave continuous variable quantum teleportation schemes still suffer from poor reliability and accuracy. Summary of the Invention

[0007] One of the objectives of this invention is to provide a microwave continuous variable quantum teleportation method that is highly reliable and accurate.

[0008] The second objective of this invention is to provide a system for implementing the microwave continuous variable quantum teleportation method.

[0009] The microwave continuous-variable quantum teleportation method provided by this invention includes the following steps:

[0010] S1. A third party uses a Joseph parametric amplifier and a microwave beam splitter to generate a dual-mode compressed state under a set low-temperature environment, and sends the dual-mode compressed state to the communication sender and the communication receiver;

[0011] S2. After receiving the signal, the communication sender performs Bell measurement to generate a feedforward signal and sends the feedforward signal to the communication receiver.

[0012] S3. The receiving party processes the signal sent by the third party based on the received feedforward signal to obtain the quantum state sent by the sending party, thus completing the microwave continuous variable quantum teleportation.

[0013] Step S1 involves a third party using a Joseph parametric amplifier and a microwave beam splitter to generate a dual-mode compressed state under a set low-temperature environment, and then sending the dual-mode compressed state to the communication transmitter and receiver. Specifically, this includes the following steps:

[0014] A. Generate a vacuum state under a set low-temperature environment and send the vacuum state to two Joseph parametric amplifiers;

[0015] B. The output signals of the two Joseph parametric amplifiers are mixed through a microwave beam splitter to obtain a dual-mode compressed state;

[0016] C. Through a set low-temperature microwave channel, one state of the dual-mode compressed state is sent to the communication sender, and the other state of the dual-mode compressed state is sent to the communication receiver.

[0017] Step A, which describes generating a vacuum state under a set low-temperature environment and sending the vacuum state to two Joseph parametric amplifiers, specifically includes the following steps:

[0018] A vacuum state is generated under a set low-temperature environment and sent to two Joseph parametric amplifiers. The two Joseph parametric amplifiers output two single-mode compressed states; the two Joseph parametric amplifiers have the same compression energy level.

[0019] The input and output states of the Joseph parametric amplifier satisfy the following formula:

[0020]

[0021] In the formula This refers to the output state of the Joseph parametric amplifier; Represents the annihilation operator. Indicates the generation of an operator. and Used to describe the input field mode; r is the compression coefficient, and satisfies g x The gain coefficient for the x-component of the position variable; g p is the amplification factor for the p-component;

[0022] The frequency of the external pump generated by the oscillating magnetic flux of the DC superconducting quantum interference device is f. pump The signal wave frequency is f signal The DC superconducting quantum interference device employs phase-sensitive amplification; the phase-sensitive amplification refers to the amplification time f... pump ≠2f signal ;

[0023] In phase-sensitive amplification, one component can be compressed while the other component is decompressed. The compression and decompression coefficients are denoted as G. i i takes the value 1 or 2, G1 is the degeneracy gain of Joseph parametric amplifier 1, and G2 is the degeneracy gain of Joseph parametric amplifier 2.

[0024] The noise introduced by the Joseph parametric amplifier is represented by η. i ;

[0025] G i and η i Satisfying the relation And G1G2=1.

[0026] Step B, which involves mixing the output signals of the two Joseph parametric amplifiers using a microwave beam splitter to obtain a dual-mode compressed state, specifically includes the following steps:

[0027] The output signals of the two Joseph parametric amplifiers are in an orthogonal single-mode compressed state;

[0028] The orthogonal single-mode compressed states are mixed on a microwave beam splitter to obtain symmetrical two-mode compressed states;

[0029] The microwave beam splitter is a 50:50 microwave beam splitter.

[0030] Step S2 describes the communication sender performing Bell measurement to generate a feedforward signal after receiving the signal, and then sending the feedforward signal to the communication receiver. This specifically includes the following steps:

[0031] a. After receiving the signal, the communication transmitter mixes the quantum state to be transmitted and the received dual-mode squeezed state on a microwave beam splitter, and then performs Bell measurement to generate a feedforward signal;

[0032] b. Send the generated feedforward signal to the communication receiver.

[0033] After receiving the signal, the communication transmitter in step a mixes the quantum state to be transmitted and the received dual-mode squeezed state on a microwave beam splitter, and then performs Bell measurement to generate a feedforward signal. The specific steps include the following:

[0034] After receiving the signal, the communication transmitter mixes the quantum state to be transmitted and the received dual-mode compressed state on the first microwave beam splitter; the first microwave beam splitter is a 50:50 microwave beam splitter.

[0035] The output signal of the microwave beam splitter is input into a pair of measurement Joseph parametric amplifiers; the pair of measurement Joseph parametric amplifiers amplify the input signal with strong phase sensitivity at the same gain and orthogonal amplification angle;

[0036] The output of the measured Joseph parametric amplifier is superimposed on the second microwave beam splitter to obtain the feedforward signal;

[0037] The first microwave beam splitter and the second microwave beam splitter are denoted as follows: Where I2 is a 2×2 identity matrix and 02 is a 2×2 zero matrix;

[0038] The aforementioned strong phase-sensitive amplification is represented by the matrix as follows: Where J3 is the matrix form for measuring the Joseph parametric amplifier and J4 represents the matrix form of another measurement Joseph parametric amplifier and G is the degenerate gain of the Joseph parametric amplifier.

[0039] The low-temperature microwave channel set in step C specifically refers to using an Nb / Al coaxial cable as the set low-temperature microwave channel; the generation of the feedforward signal sent to the communication receiver in step b specifically refers to sending the generation of the feedforward signal to the communication receiver through an Nb / Al superconducting coaxial cable.

[0040] Step S3, where the communication receiver processes the signal sent by the third party based on the received feedforward signal to obtain the quantum state sent by the communication sender, specifically includes the following steps:

[0041] The receiving party inputs the received feedforward signal into the directional coupler. The directional coupler processes the signal sent by the third party based on the feedforward signal, and the output signal is the quantum state sent by the sending party.

[0042] The matrix representation of the directional coupler is as follows: β is the coupling coefficient of the directional coupler;

[0043] When the receiver receives the feedforward signal from the sender, it amplifies the received feedforward signal using a low-temperature high electron mobility transistor.

[0044] This invention provides a system for realizing the microwave continuous-variable quantum teleportation method, comprising a third-party module, a transmitting module, and a receiving module; the output of the third-party module is connected to both the transmitting and receiving modules; the output of the transmitting module is connected to the receiving module; the third-party module is used to generate a dual-mode squeezed state under a set low-temperature environment using a Joseph parametric amplifier and a microwave beam splitter, and sends the dual-mode squeezed state to the transmitting and receiving modules; the transmitting module is used to perform Bell measurements on the received signal to generate a feedforward signal, and sends the feedforward signal to the receiving module; the receiving module is used to process the signal sent by the third party based on the received feedforward signal to obtain the quantum state sent by the communicating sender, thus completing the microwave continuous-variable quantum teleportation.

[0045] The microwave continuous variable quantum teleportation method and system provided by this invention, through innovative design of the continuous variable quantum teleportation scheme and signal processing method, not only realizes microwave continuous variable quantum teleportation, but also has better reliability and accuracy. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the method flow of the present invention.

[0047] Figure 2 This is a schematic diagram of the functional modules of the system of the present invention. Detailed Implementation

[0048] like Figure 1 The diagram shown is a flowchart of the method of the present invention: The microwave continuous variable quantum teleportation method disclosed in this invention includes the following steps:

[0049] S1. A third party uses a Joseph parametric amplifier and a microwave beam splitter to generate a dual-mode compressed state under a set low-temperature environment, and then sends the dual-mode compressed state to the communication sender and receiver; specifically, it includes the following steps:

[0050] A. Generate a vacuum state under a set low-temperature environment and send the vacuum state to two Joseph parametric amplifiers; specifically including the following steps:

[0051] A vacuum state is generated under a set low-temperature environment and sent to two Joseph parametric amplifiers. The two Joseph parametric amplifiers output two single-mode compressed states; the two Joseph parametric amplifiers have the same compression energy level.

[0052] The Josephson parametric amplifier (JPA) is a coplanar waveguide resonator line terminated by a DC superconducting quantum interference device (dc SQUID). A DC SQUID is a highly sensitive quantum interference device composed of two parallel Josephson junctions. By adjusting the DC flux on the SQUID, its effective inductance value can be precisely controlled, thus enabling the JPA to efficiently process microwave signals. The input and output states of the Josephson parametric amplifier satisfy the following equation:

[0053]

[0054] In the formula This refers to the output state of the Joseph parametric amplifier; Represents the annihilation operator. The generator operator and the input field mode are used to describe the input field mode. r is the compression coefficient, and satisfies... g x G represents the gain coefficient of the position variable x-component, corresponding to the amplification of the output state on the position x-component compared to the input state. p is the amplification factor of the p component, corresponding to the degree of amplification of the output state in the momentum p component compared to the input state;

[0055] The DC superconducting quantum interference device (CQFID) provides tunable magnetic flux for the resonator and enables parameter phase-sensitive amplification, which is crucial for generating squeezed microwave states. The frequency of the external pump generated by the oscillating magnetic flux of the DC superconducting quantum interference device is f. pump The signal wave frequency is f signal The DC superconducting quantum interference device employs phase-sensitive amplification; the phase-sensitive amplification refers to the amplification time f... pump ≠2f signal ;

[0056] In phase-sensitive amplification, one component can be compressed while the other component is decompressed. The compression and decompression coefficients are denoted as G. i i takes the value 1 or 2, G1 is the degeneracy gain of Joseph parametric amplifier 1, and G2 is the degeneracy gain of Joseph parametric amplifier 2.

[0057] The noise introduced by the Joseph parametric amplifier is represented by η. i ;

[0058] G i and η i Satisfying the relation And G1G2=1; when G1G2=1, noiseless amplification can be achieved, that is, the compressed microwave state generation is completed;

[0059] B. The output signals of the two Joseph parametric amplifiers are mixed through a microwave beam splitter to obtain a dual-mode compressed state; specifically, the following steps are included:

[0060] The output signals of the two Joseph parametric amplifiers are in an orthogonal single-mode compressed state;

[0061] The orthogonal single-mode compressed states are mixed on a microwave beam splitter to obtain symmetrical two-mode compressed states;

[0062] The microwave beam splitter is a 50:50 microwave beam splitter;

[0063] C. Through a set low-temperature microwave channel, one state of the dual-mode compressed state is sent to the communication transmitter, and the other state of the dual-mode compressed state is sent to the communication receiver; the set low-temperature microwave channel is specifically an Nb / Al coaxial cable.

[0064] S2. After receiving the signal, the communication sender performs Bell measurement to generate a feedforward signal and sends the feedforward signal to the communication receiver; specifically, it includes the following steps:

[0065] a. After receiving the signal, the transmitting party mixes the quantum state to be transmitted and the received dual-mode squeezed state on a microwave beam splitter, and then performs Bell measurements to generate a feedforward signal; specifically, the steps include the following:

[0066] After receiving the signal, the communication transmitter mixes the quantum state to be transmitted and the received dual-mode compressed state on the first microwave beam splitter; the first microwave beam splitter is a 50:50 microwave beam splitter.

[0067] The output signal of the microwave beam splitter is input into a pair of measurement Joseph parametric amplifiers; the pair of measurement Joseph parametric amplifiers amplify the input signal with strong phase sensitivity at the same gain and orthogonal amplification angle;

[0068] The output of the measured Joseph parametric amplifier is superimposed on the second microwave beam splitter to obtain the feedforward signal;

[0069] The first microwave beam splitter and the second microwave beam splitter are denoted as follows: Where I2 is a 2×2 identity matrix and 02 is a 2×2 zero matrix;

[0070] The aforementioned strong phase-sensitive amplification is represented by the matrix as follows: Where J3 is the matrix form for measuring the Joseph parametric amplifier and J4 represents the matrix form of another measurement Joseph parametric amplifier and G is the degenerate gain of the Joseph parametric amplifier.

[0071] b. Send the generated feedforward signal to the communication receiver; specifically, send the generated feedforward signal to the communication receiver via an Nb / Al superconducting coaxial cable;

[0072] S3. The receiving end processes the signal sent by the third party based on the received feedforward signal to obtain the quantum state sent by the sending end, thus completing the microwave continuous variable quantum teleportation; specifically including the following steps:

[0073] The receiving party inputs the received feedforward signal into the directional coupler. The directional coupler processes the signal sent by the third party based on the feedforward signal, and the output signal is the quantum state sent by the sending party.

[0074] The matrix representation of the directional coupler is as follows: β is the coupling coefficient of the directional coupler;

[0075] When the receiver receives the feedforward signal sent by the sender, it amplifies the received feedforward signal using a low-temperature high electron mobility transistor.

[0076] Finally, through the above steps, the ideal protocol can be represented as:

[0077] like Figure 2 The above is a functional module diagram of the system of the present invention: The system for realizing the microwave continuous variable quantum teleportation method disclosed in this invention includes a third-party module, a transmitting module, and a receiving module; the output of the third-party module is connected to both the transmitting module and the receiving module; the output of the transmitting module is connected to the receiving module; the third-party module is used to generate a dual-mode squeezed state under a set low-temperature environment using a Joseph parametric amplifier and a microwave beam splitter, and sends the dual-mode squeezed state to the transmitting module and the receiving module; the transmitting module is used to perform Bell measurement on the received signal to generate a feedforward signal, and sends the feedforward signal to the receiving module; the receiving module is used to process the signal sent by the third party according to the received feedforward signal to obtain the quantum state sent by the communicating sender, thus completing the microwave continuous variable quantum teleportation.

Claims

1. A microwave continuous-variable quantum teleportation method, comprising the following steps: S1. A third party uses a Joseph parametric amplifier and a microwave beam splitter to generate a dual-mode compressed state under a set low-temperature environment, and sends the dual-mode compressed state to the communication sender and the communication receiver; S2. After receiving the signal, the communication sender performs Bell measurement to generate a feedforward signal and sends the feedforward signal to the communication receiver. S3. The receiving party processes the signal sent by the third party based on the received feedforward signal to obtain the quantum state sent by the sending party, thus completing the microwave continuous variable quantum teleportation.

2. The microwave continuous-variable quantum teleportation method according to claim 1, characterized in that... Step S1 involves a third party using a Joseph parametric amplifier and a microwave beam splitter to generate a dual-mode compressed state under a set low-temperature environment, and then sending the dual-mode compressed state to the communication transmitter and receiver. Specifically, this includes the following steps: A. Generate a vacuum state under a set low-temperature environment and send the vacuum state to two Joseph parametric amplifiers; B. The output signals of the two Joseph parametric amplifiers are mixed through a microwave beam splitter to obtain a dual-mode compressed state; C. Through a set low-temperature microwave channel, one state of the dual-mode compressed state is sent to the communication sender, and the other state of the dual-mode compressed state is sent to the communication receiver.

3. The microwave continuous-variable quantum teleportation method according to claim 2, characterized in that... Step A, which describes generating a vacuum state under a set low-temperature environment and sending the vacuum state to two Joseph parametric amplifiers, specifically includes the following steps: A vacuum state is generated under a set low-temperature environment and sent to two Joseph parametric amplifiers. The two Joseph parametric amplifiers output two single-mode compressed states; the two Joseph parametric amplifiers have the same compression energy level. The input and output states of the Joseph parametric amplifier satisfy the following formula: In the formula This refers to the output state of the Joseph parametric amplifier; Represents the annihilation operator. Indicates the generation of an operator. and Used to describe the input field mode; r is the compression coefficient, and satisfies g x The gain coefficient for the x-component of the position variable; g p is the amplification factor for the p-component; The frequency of the external pump generated by the oscillating magnetic flux of the DC superconducting quantum interference device is f. pump The signal wave frequency is f signal The DC superconducting quantum interference device employs phase-sensitive amplification; the phase-sensitive amplification refers to the amplification time f... pump ≠2f signal ; In phase-sensitive amplification, one component can be compressed while the other component is decompressed. The compression and decompression coefficients are denoted as G. i i takes the value 1 or 2, G1 is the degeneracy gain of Joseph parametric amplifier 1, and G2 is the degeneracy gain of Joseph parametric amplifier 2. The noise introduced by the Joseph parametric amplifier is represented by η. i ; G i and η i Satisfying the relation And G1G2=1.

4. The microwave continuous-variable quantum teleportation method according to claim 3, characterized in that... Step B, which involves mixing the output signals of the two Joseph parametric amplifiers using a microwave beam splitter to obtain a dual-mode compressed state, specifically includes the following steps: The output signals of the two Joseph parametric amplifiers are in an orthogonal single-mode compressed state; The orthogonal single-mode compressed states are mixed on a microwave beam splitter to obtain symmetrical two-mode compressed states; The microwave beam splitter is a 50:50 microwave beam splitter.

5. The microwave continuous-variable quantum teleportation method according to claim 4, characterized in that... Step S2 describes the communication sender performing Bell measurement to generate a feedforward signal after receiving the signal, and then sending the feedforward signal to the communication receiver. This specifically includes the following steps: a. After receiving the signal, the communication transmitter mixes the quantum state to be transmitted and the received dual-mode squeezed state on a microwave beam splitter, and then performs Bell measurement to generate a feedforward signal; b. Send the generated feedforward signal to the communication receiver.

6. The microwave continuous-variable quantum teleportation method according to claim 5, characterized in that... After receiving the signal, the communication transmitter in step a mixes the quantum state to be transmitted and the received dual-mode squeezed state on a microwave beam splitter, and then performs Bell measurement to generate a feedforward signal. The specific steps include the following: After receiving the signal, the communication transmitter mixes the quantum state to be transmitted and the received dual-mode compressed state on the first microwave beam splitter; the first microwave beam splitter is a 50:50 microwave beam splitter. The output signal of the microwave beam splitter is input into a pair of measurement Joseph parametric amplifiers; the pair of measurement Joseph parametric amplifiers amplify the input signal with strong phase sensitivity at the same gain and orthogonal amplification angle; The output of the measured Joseph parametric amplifier is superimposed on the second microwave beam splitter to obtain the feedforward signal; The first microwave beam splitter and the second microwave beam splitter are denoted as follows: Where I2 is a 2×2 identity matrix and 02 is a 2×2 zero matrix; The aforementioned strong phase-sensitive amplification is represented by the matrix as follows: Where J3 is the matrix form for measuring the Joseph parametric amplifier and J4 represents the matrix form of another measurement Joseph parametric amplifier and G is the degenerate gain of the Joseph parametric amplifier.

7. The microwave continuous-variable quantum teleportation method according to claim 6, characterized in that... The low-temperature microwave channel set in step C specifically refers to using an Nb / Al coaxial cable as the set low-temperature microwave channel; the generation of the feedforward signal sent to the communication receiver in step b specifically refers to sending the generation of the feedforward signal to the communication receiver through an Nb / Al superconducting coaxial cable.

8. The microwave continuous-variable quantum teleportation method according to claim 7, characterized in that... Step S3, where the communication receiver processes the signal sent by the third party based on the received feedforward signal to obtain the quantum state sent by the communication sender, specifically includes the following steps: The receiving party inputs the received feedforward signal into the directional coupler. The directional coupler processes the signal sent by the third party based on the feedforward signal, and the output signal is the quantum state sent by the sending party. The matrix representation of the directional coupler is as follows: β is the coupling coefficient of the directional coupler; When the receiver receives the feedforward signal from the sender, it amplifies the received feedforward signal using a low-temperature high electron mobility transistor.

9. A system for implementing the microwave continuous-variable quantum teleportation method according to any one of claims 1 to 8, characterized in that... It includes a third-party module, a transmitting module, and a receiving module; the output of the third-party module is connected to both the transmitting and receiving modules; the output of the transmitting module is connected to the receiving module; the third-party module is used to generate a dual-mode compressed state under a set low-temperature environment using a Joseph parametric amplifier and a microwave beam splitter, and then sends the dual-mode compressed state to the transmitting and receiving modules; the transmitting module is used to perform Bell measurements on the received signal to generate a feedforward signal, and then sends the feedforward signal to the receiving module; the receiving module is used to process the signal sent by the third party based on the received feedforward signal to obtain the quantum state sent by the communicating sender, thus completing microwave continuous variable quantum teleportation.

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