KR20230149628A - Method and apparatus for counterfactual controlled quantum teleportation in an integrated quantum information processing system - Google Patents

Abstract

Disclosed is an apparatus and method for supporting controlled counterfactual quantum teleportation in a quantum information processing integrated system. The controlled counterfactual quantum teleportation support method performed at the transmitting terminal includes the steps of counterfactually generating 2N GHZ (Greenberger-Horne-Zeilinger) states, selecting a random subset of the N GHZ states, and selecting the selected subset. Notifying the location of the set to the receiving terminal and the control terminal, receiving the qubit measurement results of the receiving terminal and the control terminal and confirming the consistency of the measurement results, and ensuring that the consistency of the measurement results is reliable up to a preset threshold. In this case, it includes the step of teleporting an unknown quantum state by performing a bell-based measurement on a qubit owned by the user.

Description

Apparatus and method for supporting controlled counterfactual quantum teleportation in a quantum information processing integrated system {METHOD AND APPARATUS FOR COUNTERFACTUAL CONTROLLED QUANTUM TELEPORTATION IN AN INTEGRATED QUANTUM INFORMATION PROCESSING SYSTEM}

The technical field relates to devices and methods for supporting controlled counterfactual quantum teleportation. The controlled counterfactual quantum teleportation support device and method can be applied to the counterfactual quantum communication processing unit of the quantum communication platform in the quantum information technology integrated system.

Quantum teleportation is a transmission method that uses quantum entanglement of photons to make quantum information disappear in one place and appear in another, and is a technology that can be applied to quantum computers and quantum communication.

Quantum teleportation can be said to be an essential resource for various quantum information processing technologies. Using quantum teleportation, network participants can transmit unknown quantum states between different nodes.

In 1993, Bennett et al. presented the first protocol for transmitting an unknown quantum state from one location to a remote location using a shared EPR (Einstein-Pldolsky_Rosen) pair and 2-bit classical information transfer. Since then, various studies have been conducted on controlled quantum state transfer, including control methods using shared Greenberger-Horne-Zeilinger (GHZ) states instead of shared EPR pairs.

Quantum teleportation according to the prior art has in common the sharing of entanglement by sending physical particles through a channel to enable instantaneous movement of an unknown quantum state. Unlike the prior art, there is a need to implement counterfactual quantum teleportation in which the GHZ state can be shared non-locally between the transmitting/receiving terminal and the manager terminal.

Additionally, a quantum information integration system is needed that can support controlled counterfactual quantum teleportation as well as a variety of quantum information processing to support the implementation and research of related technologies.

Korean Patent No. 10-2017839 (August 28, 2019, Counterfactual Quantum Bell Analysis Method, Device, and System) US Patent No. 8,891,767 (Nov. 18, 2014, METHOD AND APPARATUS FOR DIRECT COUNTERFACTUAL QUANTUM COMMUNICATION)

The present invention aims to provide a controlled counterfactual quantum teleportation support device and method that can share entanglement between parties counterfactually, i.e. without transmitting physical particles through a channel.

Additionally, the present invention aims to provide a quantum information integration system that can support controlled counterfactual quantum teleportation as well as various quantum information processing to support the implementation and research of related technologies.

A controlled counterfactual quantum teleportation support method performed at a transmitting terminal according to an embodiment includes counterfactually generating 2N GHZ (Greenberger-Horne-Zeilinger) states, and generating a random subset of N GHZ states. selecting and notifying the location of the selected subset to the receiving terminal and the control terminal; receiving the qubit measurement results of the receiving terminal and the control terminal and confirming the consistency of the measurement results; and determining the consistency of the measurement results. It involves teleporting an unknown quantum state by performing a bell-based measurement on a qubit it owns if it can be trusted up to a threshold.

The control terminal can measure the qubit based on the Hadamard basis and notify the receiving terminal of the measurement result to reconstruct the unknown quantum state.

The control terminal may notify the measurement result through 1 bit of classical information m to approve controlled counterfactual quantum teleportation.

If communication is approved by the control terminal, the bell state corresponding to The measurement result can be notified to the receiving terminal through 2 bits m1m2, which is classical information from the set.

The receiving terminal may perform a unitary operation defined as Equation 4 on the qubit r _j based on the measurement results of the transmitting terminal and the control terminal to reconstruct the quantum state.

According to embodiments of the present invention, entanglement can be shared between parties without transmitting physical particles through a channel.

According to an embodiment of the present invention, resistance to various eavesdropping strategies is improved due to the consistency check of counterfactual properties and measurements.

According to embodiments of the present invention, it is possible to support controlled counterfactual quantum teleportation as well as various quantum information processing to support the implementation and research of related technologies.

Figure 1 is a diagram for explaining a counterfactual entanglement distribution model according to an embodiment of the present invention.
Figure 2 is a diagram showing the concept of controlled quantum teleportation according to an embodiment of the present invention.
Figure 3 is a flowchart showing the operation of a controlled counterfactual quantum teleportation support device according to an embodiment of the present invention.
Figure 4 is a diagram explaining a mechanism for performing QST in qubit transmission.
Figure 5 shows the Log infidelity of the reconstructed state and the actual state for pure states (a) and mixed states (b).
Figure 6 is a block diagram of a tomographic imaging device according to an embodiment of the present invention.
Figure 7 is a diagram showing a quantum information technology integrated system according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings and the contents described in the accompanying drawings, but the present invention is not limited or limited by the embodiments.

The terminology used herein is for describing embodiments and is not intended to limit the invention. As used herein, singular forms also include plural forms, unless specifically stated otherwise in the context. As used herein, “comprises” and/or “comprising” refers to the presence of one or more other components, steps, operations and/or elements. or does not rule out addition.

As used herein, “embodiment,” “example,” “aspect,” “example,” etc. should be construed to mean that any aspect or design described is better or advantageous than other aspects or designs. It's not like that.

Additionally, the term 'or' means 'inclusive or' rather than 'exclusive or'. That is, unless otherwise stated or clear from the context, the expression 'x uses a or b' means any of the natural inclusive permutations.

Additionally, as used in this specification and claims, the singular expressions “a” or “an” generally mean “one or more,” unless otherwise indicated or it is clear from the context that the singular refers to singular forms. It should be interpreted as

Additionally, terms such as first and second used in this specification and claims may be used to describe various components, but the components should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another.

Unless otherwise defined, all terms (including technical and scientific terms) used in this specification may be used with meanings that can be commonly understood by those skilled in the art to which the present invention pertains. Additionally, terms defined in commonly used dictionaries are not interpreted ideally or excessively unless clearly specifically defined.

Meanwhile, in describing the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. In addition, the terminology used in this specification is a term used to appropriately express the embodiments of the present invention, and may vary depending on the intention of the user or operator or the customs of the field to which the present invention belongs. Therefore, definitions of these terms should be made based on the content throughout this specification.

Figure 1 is a diagram for explaining a counterfactual entanglement distribution model according to an embodiment of the present invention.

Referring to FIG. 1, the first terminal (Alice) 110, the second terminal (Bob) 120, and the third terminal (Charlie) 130 can each operate as a transmitting terminal, a receiving terminal, and a control terminal. there is. For example, when Alice (110) sends quantum information to Bob (120), Charlie (130) acts as a control terminal, and conversely, it is also possible for Bob (120) to send quantum information to Alice (130). do. As such, the controlled quantum teleportation protocol according to an embodiment of the present invention assumes a three-party quantum network.

Meanwhile, in FIG. 1, reference numeral 140 'SW' refers to a quantum channel including a switchable mirror and a switchable rotor, QAO is an abbreviation for quantum absorptive object, and V-CQZ is a vertical ( Vertical) indicates that it contains a CQZ gate, and H-CQZ indicates that it contains a horizontal (Horizontal) CQZ gate.

[Step 1]

In the first step, each terminal counterfactually generates 2N GHZ states.

To safely perform controlled counterfactual quantum teleportation, Alice, Bob, and Charlie use a CQZ (Counterfactual quantum Zeno) gate to counterfactually generate 2N GHZ states. Here, N represents a natural number, and each terminal generates a 2N tripartie GHZ state with one qubit of the 2N GHZ state.

Alice, assumed to be a transmitting terminal, has her qubit operate as a quantum absorptive object (QAO) in each round of GHZ state creation in order to counterfactually distribute entanglement. Prepare the qubit in this state. At this time, Bob and Charlie each and Prepare the qubit in the in state.

Bob and Charlie alternately connect with Alice through quantum channels using CQZ gates in each round of GHZ state generation, as shown in Figure 1.

At the end of each round, the initial states of Alice, Bob, and Charlie are converted as shown in Equation 1.

[Equation 1]

,

.

Here, A, B, and C are indices representing Alice, Bob, and Charlie, respectively, and i refers to the index representing the ith round of GHZ state creation.

[Second stage]

In the second step, Alice, Bob, and Charlie perform qubit measurements and announce the results.

First, for security check, Alice selects a random subset of N GHZ states among 2N GHZ states and announces the location of the selected subset.

Bob and Charlie randomly select a measurement basis from the {x, y} set, perform measurements on each qubit, and report the measurement results and the selected basis set.

Alice compares or matches the measurement results of Bob and Charlie by referring to the measurement result table after Bob and Charlie's measurements as shown in [Table 1]. Through this, you can check whether the measurement results are consistent.

If the consistency of the measurement results is reliable up to a preset acceptable threshold, Alice, Bob, and Charlie can perform the next steps. That is, Alice, Bob, and Charlie can transmit arbitrary unknown qubits in a tripartite quantum network using N GHZ states other than the subset selected in the next step.

Meanwhile, considering that each party can operate as a transmitting terminal, receiving terminal, and control terminal, the GHZ state subscripts will be expressed as s, r, and c in the following description. Here, s, r, and c represent qubits provided (or owned by the corresponding terminal) in the transmitting terminal, receiving terminal, and control terminal, respectively.

[Step 3]

In the third step, the transmitting terminal teleports the unknown quantum state by performing a bell-based measurement on the qubit it owns. More specifically, the unknown quantum state defined as Equation 2: Assume that the transmitting terminal transmits.

[Equation 2]

,

.

The combination state of the unknown quantum state and the GHZ state can be expressed as Equation 3.

[Equation 3]

,

.

here, and represents the bell state, and j represents the jth round of controlled quantum teleportation.

In the third step, the transmitting terminal performs Bell basis measurements on qubits q and s _j , and records and maintains the measurement results.

[ Step 4 ]

In the fourth step, the control terminal measures the qubit based on the Hadamard basis and notifies the receiving terminal of the measurement result to reconstruct the unknown quantum state.

More specifically, the control terminal performs the Hadamard gate H on qubit c _j and measures the qubit as a computational basis. The control terminal notifies the measurement result through 1 bit of classical information m to approve the controlled counterfactual quantum teleportation.

When the control terminal approves communication between the sending terminal and the receiving terminal, the sending terminal is in the ring state. corresponding to The measurement result is notified to the control terminal and the receiving terminal through 2 bits of m1m2, which is classical information from the set.

Figure 2 is a diagram showing the concept of controlled quantum teleportation according to an embodiment of the present invention.

Referring to FIG. 2, it can be seen that the transmitting terminal performs controlled quantum teleportation by notifying the bell measurement result under the approval of the control terminal.

[ Step 5 ]

In the fifth step, the receiving terminal reconstructs the quantum state.

More specifically, the receiving terminal performs a unitary operation defined as Equation 4 on the qubit r _j based on the measurement results of the transmitting terminal and the control terminal to reconstruct the quantum state.

[Equation 4]

Here, X and Z refer to the Pauli x and z operators, respectively.

The method described through steps 1 to 5 can reconstruct an unknown quantum state sequence under the approval of a control terminal performing control. Therefore, it is safer against various attack strategies and can be used in a multi-party communication system.

If a terminal attempting eavesdropping attempts to participate in the entanglement distribution process, it may be in an entanglement relationship, but the terminal attempting eavesdropping may be detected during the security check process of the second stage.

Additionally, if a terminal attempting eavesdropping adds invisible photons to steal Alice's unknown quantum state, more errors may occur in the security check step due to the invisible photons.

Figure 3 is a flowchart showing the operation of a controlled counterfactual quantum teleportation support device according to an embodiment of the present invention.

Here, the controlled counterfactual quantum teleportation support device may be any one of a transmitting terminal, a receiving terminal, and a control terminal, and Figure 3 corresponds to the case where the controlled counterfactual quantum teleportation support device is a transmitting terminal.

Referring to FIG. 3, the transmitting terminal counterfactually generates 2N GHZ (Greenberger-Horne-Zeilinger) states in step 310.

In step 320, the transmitting terminal selects a random subset of N GHZ states and notifies the location of the selected subset.

In step 330, the transmitting terminal checks whether the measurement results are consistent.

If the consistency of the measurement result is reliable up to a preset acceptable threshold, the transmitting terminal performs bell-based measurement on the owned qubit in step 340.

Afterwards, if communication is approved by the control terminal, in step 350, the transmitting terminal notifies the measurement result using the classic 2 bits corresponding to the bell state.

Hereinafter, a quantum state tomography processing unit that can be applied to the quantum experiment platform in the quantum information technology integrated system of the present invention will be described.

Quantum State Tomography (QST) is a quantum information processing task to determine unknown quantum states. This work is performed by measuring an ensemble of identically prepared quantum systems and inferring their states using various estimation methods. When the quantum state passes through the maximum noise depolarization channel with a clear causal sequence (classical trajectory) input before measurement, the quantum state switches to the maximum mixed state, making QST impossible.

Instead of propagating quantum states through classical trajectories, the proposed method here sets the channels in an infinite causal order (ICO). In this specification, we show that by setting a depolarizing channel in ICO, QST can be performed even if the channel is maximally noisy. And/or, this specification examines the impact of ICO on QST through linear regression estimation when the channel has no maximum noise. And/or, the present disclosure shows that configuring channels in an ICO arrangement is advantageous when the channels have maximum noise.

The quantum state tomography processing unit according to an embodiment of the present invention transmits the quantum state to be estimated to the quantum switch, performs quantum state tomography in the state output from the quantum switch, and calculates the output of the quantum state tomography and algebra. Based on this, the initial state can be estimated.

Quantum work that determines the state of an unknown system can be called quantum state tomography (QST). QST can consist of two steps.

First, measurements are performed on identically prepared copies of the quantum state.

Next, the quantum state is reconstructed using classical statistical estimation methods. Methods to construct a quantum state are linear inversion (MLE), maximum likelihood estimation, Bayesian estimation method, and linear regression. There may be.

Linear inversion can be performed assuming an ideal environment. Therefore, if an error occurs during qubit measurement, the recovered state may not be the physical state. MLE finds the density matrix that provides the highest probability of generating a set of measurement data determined by numerical optimization. The Bayesian method uses the Bayesian theorem to determine the posterior probability distribution p(ρ|D) with knowledge of the prior probability distribution p(ρ). Here, D means measurement data.

In traditional quantum communication, quantum messages are a series of communication channels. and When transmitted through a channel, the order of messages transmitted through the channel is After passing or first After passing through It can be defined as passing through.

Quantum theory could allow new ways to combine quantum channels by creating superpositions of these channels. Through this, the information transfer order does not correspond to the previous two states. That is, the causal order between quantum channels is infinite. The process of infinite causal order can be achieved by a quantum switch where the order of operations is controlled by quantum bits. And/or, information can be transmitted through a combination of fully depolarizing channels, superimposing two alternative sequences. Quantum switches can be used to improve quantum metrology, enhance channel capacity, identify quantum depolarization channels, and enhance the quantum internet.

Herein, we model QST through linear regression under the assumption that the quantum state is transmitted through a quantum depolarization channel with maximum noise before measurement. Additionally, in this specification, we examine the impact of setting the quantum channel to an infinite causal order on QST. And, in this specification, the infidelity of the estimated state and the actual state is compared when transmitted through a channel assembled with a definite causal sequence and ICO. The latter method can support QST for quantum depolarization channels with maximum noise.

Hereinafter, in this specification, we first look at quantum state tomography using a linear regression method and a quantum switch, and then look at QST performance when transmitting quantum states through a channel established according to a clear causal order and ICO.

Quantum state tomography Tomography )

First, we look at a linear regression approach to estimate unknown quantum states.

Kronecker's delta function, equal to 1 if can be used. means tracking the matrix (1) and (2) Hermitian operator that satisfies It can be specified as . For example, in the single-qubit case, may be the same as Equation 5 below.

[Equation 5]

The qubit density operator can be parameterized as shown in Equation 6 below.

[Equation 6]

here, and the measurement set These basis It can be assumed that it can be parameterized as shown in Equation 7 below.

[Equation 7]

here, ego, am. The measurement set used in this work is This is the Stokes measurement set. Based on Born's rule, if multiple copies of an identically prepared quantum system are measured, The probability of obtaining the measurement result may be as follows in Equation 8.

[Equation 8]

here, is a column vector is the transpose of am.

From Equation 8 above, the linear regression form for QST may be as shown in Equation 9 below.

[Equation 9]

here, ego, am.

each About status It can be assumed that the quantum system is measured N times. Measurement results The probability of obtaining can be estimated by the following equation 10.

[Equation 10]

here, is the estimation error represents the observed frequencies with . Next, the linear regression equation in Equation 9 may be as shown in Equation 11 below.

[Equation 11]

here, ego, am. For large N, is the mean 0 and the change It can converge to a distribution for a normal distribution with . If more measurements are performed, measurements of the qubit state can become more accurate. The solution to the linear regression problem in Equation 11 above is to minimize Equation 12: It can be.

[Equation 12]

measurement set This information is complete or overflowing. It can be assumed that it has a station. estimate is an unbiased estimate with a mean squared error, and asymptotically may be equivalent to Equation 13 below.

[Equation 13]

here, am.

Quantum Depolarizing Channel

Quantum information can be transmitted through quantum channels. A quantum channel can be mathematically defined as a complete positive trace that preserves the map over the density operator. While transmitted through the channel, the qubit can evolve into a fully mixed state with probability (1-q) and remain with probability q. This type of quantum channel is called quantum depolarization channel It can be called . Evolution of qubits is defined as in Equation 14 below.

[Equation 14]

Quantum Switch

As described above, a quantum system transmitted through two quantum channels evolves in a clear causal sequence, with the second channel acting on the output of the first channel. Because quantum systems can evolve even in ICOs, it is impossible to determine which process occurs before the other. This is possible because of quantum switches. Quantum switches combine quantum channels, qubits called control qubits. You can control the relative order by . control qubit When in the state, the quantum switch is We will go through quantum systems in order. control qubit If in a state, the quantum state is It passes through quantum channels in order. control qubit together with and If there is a superposition of , the quantum switch changes the channel to and It can be placed in a nested order. As a result of the quantum switch, the Kraus operator of the quantum channel can be defined as Equation 15 below.

[Equation 15]

Here, channel and The Kraus operators are respectively and It can be expressed as

The quantum switch for one qubit system can be given as Equation 16 below.

[Equation 16]

Tomography methods, simulations and results

Quantum state to infer It can be assumed that is transmitted to the measurement system through a noisy depolarizing channel in the classical trajectory. If the channel is at maximum noise, e.g. When , from Equation 10, the qubit is It can be converted to the maximum mixed state of Equation 17 below, which does not depend on .

[Equation 17]

as a result, If QST is performed in It is impossible to reconstruct.

control qubit (here, ), if the channel is set in an infinite causal sequence with ), the output of the channel can be as shown in Equation 18 below.

[Equation 18]

When measuring the control qubit in basis, the output of the channel can be converted as shown in Equation 19 below.

[Equation 19]

here, and are respectively and can represent the probability of obtaining a measurement result. If the channel is maximally noisy, from equation 19: If you perform QST on is the state meaning that it is possible to reconstruct can depend on

If you measure not You will get an estimate of

Whether the probability of a quantum state remains intact is Can be determined by quantum process tomography from Equation 19, which can be recovered as shown in Equation 20 below.

[Equation 20]

If equation 20 is applied to the above, There may be some cases where is a non-physical matrix.

For this reason, can be projected onto the physical matrix space and expressed as a space of unit traces and positive semidefinite matrices. A simple projection algorithm can be adopted, the idea of which may be to transform all the eigenvalues of the density matrix into positive values and their sum.

<MSE analysis>

If the quantum state in Equation 19 is measured, then the state for The probability of obtaining the measurement result of can be defined as follows in equation 21.

[Equation 21]

situation In the case of , the certainty can be defined as follows in Equation 22.

[Equation 22]

For the maximum noise channel (q=0), may be equal to the following equation 23:

[Equation 23]

Here, the control qubit is in the state In the case that applies, that is, In this case, better results can be obtained.

From equation 13, X can obtain the same value for both states obtained after measuring the control qubit. Therefore, there is a need to identify the differences caused by P.

To assume a contradiction, Can be expressed as Equation 26 through the following process from Equation 24 to Equation 25.

[Equation 24]

[Equation 25]

[Equation 26]

here, ego, and ego, and am.

Here, equation 26 is It can be expressed as is a contradiction. therefore, It can be done.

From Equation 17, if the quantum state is transmitted through a classical arrangement, The probability of obtaining a measurement result of And, accordingly, and A larger MSE will be given.

<Numerical Simulation>

Below, numerical simulations are performed on a single qubit system using the above-described scheme. QST is performed in pure and mixed states to ensure that the system performs well in both states.

FIG. 4 is a diagram illustrating a mechanism for performing QST in a quantum depolarization channel with maximum noise by employing a quantum switch 410 in qubit transmission.

Referring to FIG. 4, the tomography device 400 according to an embodiment configured during simulation includes a quantum switch 410, a control qubit measurement device 420, and , may include a quantum state tomography (Quantum State Tomography) device 430.

uniformly distributed according to the Haar measure and according to the Hilbert-Schmidt measure or Bures measure for mixed states. Random quantum states can be created. It is possible to model qubit transport in depolarizing channels and ICOs with maximum noise assembled from classical orbits prior to measurement. Measurements are made on each qubit. It can be performed every time. To quantify how close the actual state is to the estimate, both states The fidelity of all can be calculated.

next, Average log accuracy of quantum states can be calculated. If the states are transmitted in finite causal order and ICO, the Log infidelity of the actual pure states with this estimate can be represented as in Figure 5.

Figure 5 shows the reconstruction states for pure states (a) and mixed states (b) and actual state Indicates the log infidelity.

When real states are transmitted over channels placed in an ICO array, the log infidelity is and Measurement results can be displayed by red and green lines. Additionally, the average accuracy of the estimated state can be calculated as shown in Equation 27 below.

[Equation 27]

here, and is the measurement of the control qubit and In the case corresponding to , it may be the probability and accuracy of the estimated state.

From Figure 5, it can be seen that for the quantum depolarization channel with maximum noise, the ICO arrangement helps the QST estimation performance for both pure and mixed states. Measurement results The QST on the corresponding states is consistent with the previously described MSE analysis. A better estimate can be obtained than the corresponding states.

For example, the tomographic imaging device 600 according to the embodiment of FIG. 6 may perform the above-described operation. For example, the output passing through the quantum switch unit 610 of the tomography apparatus 600 may be expressed as Equation 18. And/or, the quantum switch unit 610 of the tomography device 600 The output of the channel from the control qubit in the basis can be converted as shown in Equation 19. And/or, the tomography unit 620 and/or the estimation unit 630 of the tomography apparatus 600 may estimate the quantum state based on a linear regression approach, as described above for quantum state tomography. . For example, the tomography unit 620 and/or the estimation unit 630 of the tomography apparatus 600 may perform the calculations of Equations 5 to 13. And/or, the tomography unit 620 and/or the estimation unit 630 of the tomography apparatus 600 is based on Equation 19. can also be reconstructed.

And/or, the tomography unit 620 and/or the estimation unit 630 of the tomography apparatus 600 is calculated by Equation 16: to or can be determined and/or estimated.

The operation of the tomography apparatus described with reference to FIG. 6 is not limited to the above-described method, and the operations described herein can be performed in various ways. Additionally, the tomographic imaging device may perform all or some of the operations described in this specification in addition to the operations of the tomographic imaging device described with reference to FIG. 6 above.

The tomography apparatus of FIG. 6 can be applied to the quantum state tomography processing unit 2031 of FIG. 7.

In this specification, we look at QST in a depolarizing channel with maximum noise. In this specification, a quantum switch was applied to enable QST in the maximum noise channel. As described herein, transmitting qubits in a quantum switching array provides more accurate quantum state estimates than transmitting them via classical orbitals. In other words, the present invention can perform accurate quantum state tomography in a depolarized quantum channel with maximum silencing.

Figure 6 is a block diagram of a tomographic imaging device according to an embodiment of the present invention.

Referring to FIG. 6, the tomography apparatus 600 according to an embodiment of the present invention includes a quantum switch unit 610 that is controlled by a control qubit and receives a quantum state to be estimated, and a quantum switch unit 610. It includes a tomography unit 620 that performs quantum state tomography on the output state, and an estimation unit 630 that estimates the initial state based on the output of the tomography unit 620 and algebra, even in the maximum noise channel. Quantum state imaging can be performed.

And/or, the quantum switch unit 610 may combine quantum channels.

And/or, tomography may be based on linear regression estimation.

And/or, the maximum noise channel can be set to Indefinite Causal Order (ICO).

And/or, the maximum noise channel may be a quantum depolarization channel.

According to another embodiment, the tomography device 600 transmits the quantum state to be estimated to the quantum switch, performs quantum state tomography in the state output from the quantum switch, and uses algebra in predicting the state output from the quantum switch. By performing , the quantum state tomography accuracy can be improved in the maximum noise depolarization quantum channel by estimating the initial state.

According to another embodiment, the tomography device 600 transmits the quantum state to be estimated to the quantum switch, performs quantum state tomography in the state output from the quantum switch, and uses algebra in predicting the state output from the quantum switch. By performing to estimate the initial state, quantum state tomography can be performed even when the channel noise is maximum.

And/or, when the quantum state is transmitted in a maximally noisy depolarizing quantum channel, it transforms into a maximally mixed state, making it impossible to perform quantum state tomography. Even when the channel noise is maximum, the quantum state tomography device according to one embodiment first transmits the quantum state to be estimated to the quantum switch, performs quantum state tomography in the state output from the quantum switch, and outputs from the quantum switch. The initial state can be estimated by performing algebra on the prediction of the resulting state.

The operations of the tomography apparatus described with reference to FIG. 6 are not limited to this, and all or some of the operations described in this specification may be performed by the tomography apparatus.

Figure 7 is a diagram showing a quantum information technology integrated system according to an embodiment of the present invention.

Referring to FIG. 7, it includes a quantum communication platform (2010), a quantum computing platform (2020), a quantum observation and analysis platform (2030), a platform control unit (2040), and a platform interface unit (2050).

Quantum Communication Platform (2010) is a platform that provides implementation and experimentation of element technologies related to quantum communication and quantum information communication.

Quantum communication platform (2010) is a quantum key distribution processor (2011) that performs secure communication through quantum key distribution (QKD), particle-free information transmission in which no particles exist in the channel. and a counterfactual quantum communication processing unit (2013) that performs a new form of full-duplex information transmission and blind tele-computation, and radio resource management when applying quantum communication to next-generation mobile communication. It may include a radio resource management processing unit 2015 that performs and a network interference control processing unit 2017 that performs network interference control. For example, the counterfactual quantum communication processing unit 2013 may perform the role of at least one of the first terminal (Alice), the second terminal (Bob), and the third terminal (Charlie).

The Quantum Computing Platform (2020) is a platform that provides implementation and experiments of element technologies for the practical use of quantum computers capable of exponentially fast parallel calculations based on quantum algorithms.

The quantum computing platform (2020) includes a variant quantum algorithm processor (2021) that provides a variational quantum algorithm (VQA) specifically designed for noisy intermediate-scale quantum (NISQ) devices, the Grover search algorithm or Quantum search algorithm processing unit (2023) that provides a quantum search algorithm (QSA) such as a quantum counting algorithm and quantum machine learning such as quantum reinforcement learning of a multi-body Hamiltonian It may include a quantum machine learning processing unit (2025) that provides learning: QML) technology.

The Quantum Observation and Analysis Platform (2030) supports quantum measurements and quantum simulations and directly utilizes the quantum properties of real particles, such as quantum coherence and entanglement, solving problems that are difficult to simulate on classical computers. It is a platform for doing this.

The quantum observation and analysis platform (2030) includes a quantum state tomography processor (2031) that provides quantum state tomography, a quantum state measurement processor (2033) that supports quantum state measurements, and quantum correlation measurements for qubit measurements and experiments. It includes a quantum correlation measurement processing unit 2035 and a tensor network experiment processing unit 2037 supporting tensor network and Hamiltonian-based quantum simulation for simulation.

The platform control unit 240 stores the history and measurement results performed on the quantum communication platform (2010), the quantum computing platform (2020), and the quantum observation and analysis platform (2030), and controls the components of the other platform from any one platform. When you need to use it, you can perform an action to connect it.

For example, if a Bell measurement is required in the counterfactual quantum communication processing unit (2013) of the quantum communication platform (2010), the Bell measurement is performed in the quantum state measurement processing unit (2033) or the quantum correlation measurement processing unit (2033) of the quantum observation and analysis platform (2030). 2035).

The platform interface unit 2050 may be a computer device that allows a user or experimenter to access each platform. For example, a user can access the quantum observation and analysis platform 2030 through the platform interface unit 2050 and run a desired quantum simulation.

Quantum information technology is converging with the fields of communication, algorithms, and simulation technologies, and research is ongoing to overcome the limitations of next-generation mobile communications, such as network security, wireless resource management, channel estimation, and network interference management. Accordingly, the components included in each of the quantum communication platform (2010), the quantum computing platform (2020), and the quantum observation and analysis platform (2030) may be replaced or improved according to the development and emergence of each technology.

For example, the quantum key distribution processor 2011 can be improved to provide technology for integration into the security layer of the next-generation mobile communication system.

For example, each component of the quantum communication platform (2010) can be improved for use in interference management of next-generation mobile communication systems that require intelligent network functions.

The device described above may be implemented with hardware components, software components, and/or a combination of hardware components and software components. For example, devices and components described in embodiments may include, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable array (FPA), It may be implemented using one or more general-purpose or special-purpose computers, such as a programmable logic unit (PLU), microprocessor, or any other device capable of executing and responding to instructions. A processing device may execute an operating system (OS) and one or more software applications that run on the operating system. Additionally, a processing device may access, store, manipulate, process, and generate data in response to the execution of software. For ease of understanding, a single processing device may be described as being used; however, those skilled in the art will understand that a processing device includes multiple processing elements and/or multiple types of processing elements. It can be seen that it may include. For example, a processing device may include a plurality of processors or one processor and one controller. Additionally, other processing configurations, such as parallel processors, are possible.

The method according to the embodiment may be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, etc., singly or in combination. Program instructions recorded on the medium may be specially designed and configured for the embodiment or may be known and available to those skilled in the art of computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical media such as CD-ROMs and DVDs, and magnetic media such as floptical disks. -Includes optical media (magneto-optical media) and hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, etc. Examples of program instructions include machine language code, such as that produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter, etc. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

As described above, although the embodiments have been described with limited examples and drawings, various modifications and variations can be made by those skilled in the art from the above description. For example, the described techniques are performed in a different order than the described method, and/or components of the described system, structure, device, circuit, etc. are combined or combined in a different form than the described method, or other components are used. Alternatively, appropriate results may be achieved even if substituted or substituted by an equivalent.

Therefore, other implementations, other embodiments, and equivalents of the claims also fall within the scope of the claims described below.

Claims (6)

Counterfactually generating 2N GHZ (Greenberger-Horne-Zeilinger) states;
Selecting a random subset of N GHZ states and notifying the location of the selected subset to the receiving terminal and the control terminal;
Receiving qubit measurement results from the receiving terminal and the control terminal and confirming consistency of the measurement results; and
Including the step of teleporting an unknown quantum state by performing a bell-based measurement on a qubit owned by the user when the consistency of the measurement result is reliable up to a preset threshold.
A method for supporting controlled counterfactual quantum teleportation performed at a transmitting terminal in a quantum information processing integrated system. According to paragraph 1,
The control terminal measures the qubit based on the Hadamard basis and notifies the receiving terminal of the measurement result to reconstruct the unknown quantum state.
A method for supporting controlled counterfactual quantum teleportation performed at a transmitting terminal in a quantum information processing integrated system. According to paragraph 2,
The control terminal notifies the measurement result through 1 bit of classical information m to approve controlled counterfactual quantum teleportation.
A method for supporting controlled counterfactual quantum teleportation performed at a transmitting terminal in a quantum information processing integrated system. According to paragraph 3,
If communication is approved by the control terminal, the bell state corresponding to Notifying the receiving terminal of the measurement result through 2 bits of m1m2, which is classical information from the set.
A method for supporting controlled counterfactual quantum teleportation performed at a transmitting terminal in a quantum information processing integrated system. According to paragraph 4,
The receiving terminal performs a unitary operation defined as Equation 4 in the qubit r _j based on the measurement results of the transmitting terminal and the control terminal to reconstruct the quantum state.
[Equation 4]

Here, X and Z stand for Pauli x and z operators, respectively.
A method for supporting controlled counterfactual quantum teleportation performed at a transmitting terminal in a quantum information processing integrated system. Generate 2N GHZ (Greenberger-Horne-Zeilinger) states counterfactually, select a random subset of N GHZ states, notify the location of the selected subset to the receiving terminal and the control terminal, and A counterfactual quantum communication processor that receives the qubit measurement results from the control terminal and teleports the unknown quantum state by performing bell-based measurements on the qubits it owns when the consistency of the measurement results is reliable up to a preset threshold. A quantum communication platform comprising and
A quantum state tomography processing unit that transmits the quantum state to be estimated to a quantum switch, performs quantum state tomography in the state output from the quantum switch, and estimates the initial state based on the output of the quantum state tomography and algebra. Quantum observation and analysis platform that includes
Quantum information processing integrated system.