CN112529199B - Entangled quantum state purification method, device, equipment, storage medium and product - Google Patents
Entangled quantum state purification method, device, equipment, storage medium and product Download PDFInfo
- Publication number
- CN112529199B CN112529199B CN202011541607.2A CN202011541607A CN112529199B CN 112529199 B CN112529199 B CN 112529199B CN 202011541607 A CN202011541607 A CN 202011541607A CN 112529199 B CN112529199 B CN 112529199B
- Authority
- CN
- China
- Prior art keywords
- qubits
- quantum
- qubit
- target
- measurement result
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06N—COMPUTING ARRANGEMENTS BASED ON SPECIFIC COMPUTATIONAL MODELS
- G06N10/00—Quantum computing, i.e. information processing based on quantum-mechanical phenomena
Landscapes
- Engineering & Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mathematical Analysis (AREA)
- Data Mining & Analysis (AREA)
- Evolutionary Computation (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- Computational Mathematics (AREA)
- Mathematical Optimization (AREA)
- Pure & Applied Mathematics (AREA)
- Computing Systems (AREA)
- General Engineering & Computer Science (AREA)
- Mathematical Physics (AREA)
- Software Systems (AREA)
- Artificial Intelligence (AREA)
- Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)
Abstract
The disclosure provides a method, a device, equipment, a storage medium and a product for purifying entangled quantum states, and relates to the field of quantum computing. The specific implementation scheme is as follows: determining a first set of qubits and a second set of qubits; applying a first parameterized quantum circuit corresponding to the first set of qubits to at least a portion of the first qubits in the first set of qubits and obtaining a first measurement result; applying a second parameterized quantum circuit corresponding to a second group of qubits to at least a portion of second qubits in the second group of qubits and obtaining a second measurement result, wherein the target second qubit is an entangled qubit with the target first qubit; and purifying the entangled quantum states corresponding to the target first qubit and the target second qubit at least based on the relationship between the first measurement result and the second measurement result, and obtaining a target purified quantum state. Thus, purification of entangled quantum states is achieved.
Description
Technical Field
The present application relates to the field of data processing, and more particularly to the field of quantum computing.
Background
One of the most important resources in Quantum technology is Quantum entanglement (Quantum entanglement), which is a basic component of Quantum computation and Quantum information processing. Among them, the most important is the Bell state (Bell state) used to describe the maximum entangled state between two qubits (or quantum systems), including four maximum entangled states. The Bell state plays a vital role in scenes such as quantum secure communication, distributed quantum computation and the like. Unfortunately, the entangled states produced by quantum devices are often noisy, yet some distance from the ideal bell state. Therefore, how to effectively perform Entanglement distillation (Entanglement distillation), also called Entanglement purification (Entanglement purification), on recent quantum devices by feasible physical operations to purify the bell state from the entangled state with noise becomes a core problem in quantum technology.
Disclosure of Invention
The application provides a method, a device, equipment, a storage medium and a product for purifying entangled quantum states.
According to an aspect of the present application, there is provided an entangled quantum state purification method comprising:
determining a first group of qubits and a second group of qubits, wherein the first group of qubits includes n first qubits and the second group of qubits includes n second qubits;
applying a first parameterized quantum circuit corresponding to the first group of qubits to at least part of first qubits in the first group of qubits, and obtaining state information of other first qubits in the first group of qubits after the first parameterized quantum circuit is applied, except for a target first qubit, to obtain a first measurement result;
applying a second parameterized quantum circuit corresponding to the second group of qubits to at least part of second qubits in the second group of qubits, and obtaining state information of other second qubits in the second group of qubits after the second parameterized quantum circuit is applied, except for a target second qubit, so as to obtain a second measurement result, wherein the target second qubit is a qubit entangled with the target first qubit;
and purifying the entangled quantum states corresponding to the target first qubit and the target second qubit at least based on the relationship between the first measurement result and the second measurement result, and obtaining a target purified quantum state.
According to another aspect of the present application, there is provided an entangled quantum state purification device comprising:
the apparatus comprises a qubit group obtaining unit, a qubit group obtaining unit and a qubit group obtaining unit, wherein the qubit group obtaining unit is used for determining a first group of qubits and a second group of qubits, the first group of qubits comprises n first qubits, and the second group of qubits comprises n second qubits;
the first parameterized quantum circuit processing unit is used for applying a first parameterized quantum circuit corresponding to the first group of qubits to at least part of first qubits in the first group of qubits and obtaining state information of other first qubits except the target first qubit in the first group of qubits after the first parameterized quantum circuit is applied to the first group of qubits so as to obtain a first measurement result;
a second parameterized quantum circuit processing unit, configured to apply a second parameterized quantum circuit corresponding to the second group of qubits to at least part of second qubits in the second group of qubits and obtain state information of other second qubits, except a target second qubit, in the second group of qubits applied to the second parameterized quantum circuit, so as to obtain a second measurement result, where the target second qubit is a qubit entangled with the target first qubit;
and the purification processing unit is used for purifying the entangled quantum states corresponding to the target first qubit and the target second qubit at least based on the relationship between the first measurement result and the second measurement result, and obtaining a target purified quantum state.
According to another aspect of the present disclosure, there is provided an electronic device including:
at least one processor; and
a memory communicatively coupled to the at least one processor; wherein the content of the first and second substances,
the memory stores instructions executable by the at least one processor to enable the at least one processor to perform a method according to any one of the embodiments of the present disclosure.
According to another aspect of the present disclosure, there is provided a non-transitory computer readable storage medium having stored thereon computer instructions for causing a computer to perform a method in any of the embodiments of the present disclosure.
According to another aspect of the present disclosure, a computer program product is provided, comprising a computer program which, when executed by a processor, implements the method in any of the embodiments of the present disclosure.
The technology realizes the entanglement purification of entangled quantum states.
It should be understood that the statements in this section do not necessarily identify key or critical features of the embodiments of the present application, nor do they limit the scope of the present application. Other features of the present application will become apparent from the following description.
Drawings
The drawings are included to provide a better understanding of the present solution and are not intended to limit the present application. Wherein:
FIG. 1 is a schematic flow chart of an implementation of a entangled quantum state purification method according to an embodiment of the present application;
FIG. 2 is a schematic flow chart of an implementation of an entangled quantum state purification method in a specific example according to an embodiment of the present application;
FIG. 3 is a schematic diagram of an entangled quantum state purification method in a particular example in which parameterized quantum circuits are applied to qubits in accordance with embodiments of the present application;
FIG. 4 is a schematic diagram of an entangled quantum state purification device according to an embodiment of the present application;
fig. 5 is a block diagram of an electronic device for implementing the entangled quantum state purification method of an embodiment of the present application.
Detailed Description
The following description of the exemplary embodiments of the present application, taken in conjunction with the accompanying drawings, includes various details of the embodiments of the application for the understanding of the same, which are to be considered exemplary only. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the present application. Also, descriptions of well-known functions and constructions are omitted in the following description for clarity and conciseness.
In Quantum technology, Quantum entanglement is a key resource for realizing various Quantum information technologies such as Quantum secure communication, Quantum computation, Quantum network and the like, and a bell state is an important basic resource of a Quantum key distribution (Quantum key distribution), Quantum super-dense coding (Quantum super-dense coding), Quantum invisible state (Quantum termination) and the like. Therefore, the high-fidelity bell state is a fundamental stone for quantum information processing, in other words, quantum entanglement purification is the most core and practical direction in quantum information, and if the high-fidelity bell state can be obtained through purification and is suitable for a practical entanglement purification scheme of recent quantum equipment, the development of quantum network and distributed quantum computing can be greatly promoted.
Based on this, the scheme of the application provides a method, a device, equipment, a storage medium and a product for purifying an entangled quantum state, which can realize the conversion of the entangled quantum state (namely, the quantum entangled state) on recent quantum equipment, and purify to obtain the quantum state similar to the bell state, for example, can realize the conversion of the entangled state of an isotropic state, and has high efficiency, practicability and universality. The high efficiency is to achieve the highest fidelity, the practicability is to realize on the recent quantum equipment, and the universality is to apply to the entangled quantum state in general situation.
First, the basic concept related to the present embodiment will be explained as follows:
the entangled qubits (qubits) are usually distributed in two or more locations at a distance, for example, for a quantum system composed of the qubits in the entangled state, Alice and Bob are in different laboratories, and each of the two human laboratories has a part of the qubits in the quantum system, based on which the physical operations allowed by Alice and Bob are local quantum operations and classical communication (LOCC), which may be referred to as LOCC operations, for the qubits in the respective laboratories. Here, the quantum operation refers to operations of quantum gate and quantum measurement on the qubit, and the local quantum operation means that Alice and Bob can only do the above quantum operation on the qubit in their respective laboratories; classical communication is usually used between two people, for example, between Alice and Bob through a classical communication method (e.g., using a network, etc.)Communication performed) the results from the ac quantum measurements. In this case, the particular problems of entanglement distillation are: finding an initial quantum state p in an entangled state to which a LOCC operating scheme will have been assigned to both partiesABPurifying to an entangled state with a higher fidelity (fidelity) to the Bell state, where ρABA in (B) corresponds to qubit a in Alice's laboratory and B corresponds to qubit B in Bob's laboratory, the initial quantum state ρABAnd the quantum state is the corresponding entangled quantum state after the qubit A and the qubit B are entangled. In practical applications, the higher the fidelity, the better, since the higher the fidelity, the closer to the bell state, the fidelity can be understood as the degree of similarity between two quantum states.
Secondly, the scheme of the application is explained in detail; specifically, fig. 1 is a schematic flow chart of an implementation of an entangled quantum state purification method according to an embodiment of the present application, and as shown in fig. 1, the method includes:
step S101: a first set of qubits and a second set of qubits are determined, wherein the first set of qubits includes n first qubits and the second set of qubits includes n second qubits.
Step S102: and applying a first parameterized quantum circuit corresponding to the first group of qubits to at least part of first qubits in the first group of qubits, and obtaining state information of part other first qubits except the target first qubit in the first group of qubits after the first parameterized quantum circuit is applied, so as to obtain a first measurement result.
Step S103: and applying a second parameterized quantum circuit corresponding to the second group of qubits to at least part of second qubits in the second group of qubits, and obtaining state information of other part of second qubits except for a target second qubit in the second group of qubits after the second parameterized quantum circuit is applied to obtain a second measurement result, wherein the target second qubit is a qubit entangled with the target first qubit.
Step S104: and purifying the entangled quantum states corresponding to the target first qubit and the target second qubit at least based on the relationship between the first measurement result and the second measurement result, and obtaining a target purified quantum state.
Therefore, the purification of the entangled quantum state is realized, and the purification process is not limited to the entangled state, namely, the purification operation can be carried out on the entangled state containing general noise, so that the universality is strong; furthermore, because this application scheme has adopted parameterization quantum circuit, so for this application scheme has flexibility, variety, simultaneously, still has expansibility and adaptability concurrently, can be directed against different application scenarios and quantum equipment design suitable scheme.
In a specific example of the present disclosure, the first group of qubits and the second group of qubits may also be obtained as follows; specifically, n groups of quantum bit entanglement pairs are determined, wherein the quantum bit entanglement pairs comprise at least two quantum bits entangled with each other; splitting at least two qubits included in the qubit entanglement pair into at least two groups of qubits to obtain a first group of qubits and a second group of qubits, wherein the first group of qubits includes n first qubits in the qubit entanglement pair, and the second group of qubits includes n second qubits in the qubit entanglement pair. For example, Alice and Bob share n qubit entanglement pairs, and two qubits in each qubit entanglement pair are respectively located in laboratories corresponding to Alice and Bob, that is, two qubits in each qubit entanglement pair are located in different laboratories, and the laboratories of Alice and Bob share one qubit, based on which the laboratories of Alice and Bob respectively have the n qubits in the n qubit entanglement pairs, a foundation is laid for efficient subsequent purification of entangled quantum states.
In a specific example of the present application, the entangled states to be purified can be determined by determining the n quantum ratios from the n groupsAnd selecting a target qubit entanglement pair for purification processing from the target entanglement pair, wherein the target first qubit and the target second qubit are mutually entangled qubits in the target qubit entanglement pair. Continuing with Alice and Bob as examples, the qubits in Alice's laboratory are noted: quantum bit AiI ═ 1,2, …, n; qubits in Bob laboratories are noted: quantum bit BiI is 1,2, …, n, wherein AiAnd BiIntertwined with each other and belong to a quantum system, thereby converting the qubit A into the qubit A1And qubit B1The corresponding quantum bit entanglement pair is used as a target quantum bit entanglement pair to be purified, so that a foundation is laid for realizing efficient purification of entangled quantum states subsequently.
In a specific example of the solution of the present application, after the first parameterized qubit is applied to at least a part of first qubits in the first group of qubits, in order to achieve the refinement and improve the precision of the refinement result, a second qubit entangled with the first qubit applied by the first parameterized qubit needs to be selected from the second group of qubits; further, applying the second parameterized quantum circuit corresponding to the second group of qubits to at least a portion of the second qubits in the second group of qubits as described above specifically includes: and applying a second parameterized quantum circuit corresponding to the second group of quantum bits to the selected second quantum bit entangled with the first quantum bit acted by the first parameterized quantum circuit. That is, there is a correlation between a first qubit acted on by a first parameterized quantum circuit and a second qubit acted on by a second parameterized quantum circuit, i.e., both are intertwined qubits. Therefore, a foundation is laid for the subsequent efficient realization of the purification of the entangled state.
In a specific example of the present application, the refining step may be further cycled, that is, when it is determined that the relationship between the first measurement result and the second measurement result satisfies a preset condition, a new first parameterized quantum circuit matching the first measurement result and the second measurement result is selected and applied to at least a part of the first qubits in the first group of qubits to obtain a new first measurement result, and the first measurement result is updated; selecting a new second parameterized quantum circuit matched with the first measurement result and the second measurement result, applying the new second parameterized quantum circuit to at least part of second qubits in a second group of qubits to obtain a new second measurement result, and updating the second measurement result, so as to circulate until a preset circulation frequency is reached; further, the above purifying the entangled quantum states corresponding to the target first qubit and the target second qubit based on at least the relationship between the first measurement result and the second measurement result, and obtaining a target purified quantum state specifically includes: and based on the updated relationship between the first measurement result and the second measurement result, purifying the entangled quantum states corresponding to the target first quantum bit and the target second quantum bit, and obtaining a target purified quantum state. Therefore, the purification steps are repeatedly executed, and a foundation is laid for further improving the accuracy of the purification result.
In a specific example of the scheme of the application, the refining the entangled quantum states corresponding to the target first qubit and the target second qubit based on at least the relationship between the first measurement result and the second measurement result, and obtaining a target refined quantum state specifically includes:
obtaining a purified quantum state between the target first qubit and the target second qubit when determining that the relationship between the first measurement result and the second measurement result satisfies a preset condition; and adjusting the parameters of the first parameterized quantum circuit and the parameters of the second parameterized quantum circuit based on the difference between the purified quantum state and the target quantum state so as to purify the entangled quantum states corresponding to the target first quantum bit and the target second quantum bit and obtain the target purified quantum state. Here, the preset condition may be determined based on an actual requirement of an actual scene, for example, in an example, the preset condition is that the first measurement result is equal to the second measurement result. Thus, purification of entangled quantum states is achieved.
In a specific example of the present application, the target quantum state belongs to a bayer state; here, the Bell states are four states, respectively Φ+,Φ-,Ψ+Or Ψ-. The bell state in the scheme of the application can be any one of the above four states, in other words, the scheme of the application can purify the entangled state of general noise into the bell state, and therefore the scheme of the application has strong universality.
In a specific example of the present application, after the parameter adjustment, under a condition that it is determined that the fidelity between the obtained purified quantum state and the target quantum state satisfies a preset rule, the purified quantum state corresponding to the condition that the fidelity satisfies the preset rule is taken as the target purified quantum state. Thus, purification of entangled quantum states is achieved.
In a specific example of the scheme of the present application, the method further includes: determining fidelity between the obtained purified quantum state and the target quantum state, and obtaining a loss function based on the fidelity; and minimizing the loss function in a parameter adjustment mode, and taking the purification quantum state when the loss function is at the minimum value as the target purification quantum state. Therefore, the purification of the entangled quantum states is realized by a machine learning optimization mode.
Therefore, the purification of the entangled quantum state is realized, and the purification process is not limited to the entangled state, namely, the purification operation can be carried out on the entangled state containing general noise, so that the universality is strong; furthermore, because this application scheme has adopted parameterization quantum circuit, so for this application scheme has flexibility, variety, simultaneously, still has expansibility and adaptability concurrently, can be directed against different application scenarios and quantum equipment design suitable scheme.
The present invention is further described in detail with reference to the following specific examples, and specifically, the present invention innovatively designs a quantum neural network (or a parameterized quantum circuit) based method, and obtains an entanglement purification scheme through a machine learning optimization method, and the present invention can be implemented on a specific quantum hardware device, so as to achieve the purification of any purifiable noisy entangled quantum state, and obtain a target entangled state close to the bell state, thereby making up the limitations of the existing purification scheme, and achieving the purpose of performing entanglement distillation (i.e., entanglement purification) on any noisy entangled quantum state by using a recent quantum device. Moreover, the scheme has strong expandability, can purify entangled quantum states among a plurality of quantum bits, has higher fidelity after purification, and has high efficiency, practicability and universality.
The parameterized quantum circuit U (θ) described in this example generally consists of several single-quantum-bit rotation gates and CNOT gates, several of which constitute a vector θ as an adjustable parameter in the parameterized quantum circuit; based on the method, Alice and Bob form a LOCC operation scheme by utilizing a parameterized quantum circuit prepared respectively and combining local quantum operation and classical communication, and the purpose of entanglement distillation of any entangled quantum state containing noise is achieved.
Specifically, for the present example entangled distillation, Alice and Bob share n parts of the initial quantum state ρABHere, one initial quantum state may be understood as: the quantum system corresponding to the initial quantum state comprises at least two mutually entangled quantum bits, and the scheme of the application is called as a quantum bit entanglement pair for short; for convenience of description, the description below takes an example in which two qubits entangled with each other are included in a qubit entanglement pair; certainly, in practical applications, the quantum system corresponding to the initial quantum state may further include more than two qubits in an entangled state, that is, the qubit entangled pair may further include more than two qubits, at this time, the qubits in the entangled state only need to be located in different laboratories, and each laboratory performs LOCC operation described in the present application scheme to implement entanglement purification, which is not limited in this application scheme.
Based on this, Alice and Bob share n qubit entanglement pairs, and the two qubits in each qubit entanglement pair are respectively located in the laboratories corresponding to Alice and Bob, i.e., the two qubits in a qubit entanglement pair are located in different laboratories, and Alice and Bob respectively share one of the laboratories, on the basis of which Alice and Bob respectively have the n qubits in the n qubit entanglement pairs in the laboratories.
Further, the quantum system containing the quantum bit entanglement pair has the corresponding entangled quantum state called initial quantum state ρABThis example is intended to refer to this initial quantum state ρABPurification to target quantum state sigmaAB(such as a bell state). The specific operation comprises the following steps: first, Alice and Bob each prepare a parameterized quantum circuit for the refinement operation, which is used to perform a local quantum operation. In the operation process, Alice and Bob can measure and communicate the measurement results through classical communication, further determine subsequent local quantum operation based on the obtained measurement result of the other party and the measurement result of the other party, and then cycle the operation for N-1 times, namely execute the operation for N times. Here, the classical communication mode and the number N may be determined by specific application scenarios and experimental equipment, which is not limited in the present application. Obtaining an output state rho 'after all LOCC operations are finished'ABAt this time, the output state ρ'ABAnd target quantum state sigmaABFidelity F (ρ'AB,σAB) And defines a loss function L ═ 1-F (ρ'AB,σAB). Parameters in the parameterized quantum circuit are adjusted using a parameter optimization method in machine learning to minimize the loss function L. When the loss function is minimized, e.g., converged, the parameterized quantum circuit represents the LOCC operation that Alice and Bob can use to experimentally assign the initial quantum state ρABPurification to target quantum state sigmaABThe LOCC operating scheme of (1).
Further, below, the target quantum state σ is expressedABIs a Bell state phi+For example, the detailed description will be made, here, Bell state Φ+Is one of four states, in practical application, the target quantum state can also be other forms of Bell state,the scheme of the application is not limited to the method.
Based on this, the input is the initial quantum state ρABAnd the output purified quantum state rho'ABAnd the output purified quantum state rho'ABAnd target quantum state phi+(also referred to as target Bell states) with Tr (Φ)+ρ′AB) Where Tr (C) represents the trace (trace) of matrix C, i.e., the sum of the elements on the diagonal. Also as input is the number of rounds N of classical communication.
Further, as shown in fig. 2, the specific steps include:
step 1: alice and Bob each prepare a number of parametric quantum circuits with adjustable parameters, and the parametric quantum circuits prepared by Alice are denoted as
And wherein the initialization parameter is alpha1,α2…; bob prepared parameterized Quantum circuits
And wherein the initialization parameter is beta1,β2…; each person can quantum-operate the n qubits in the respective hand based on a respective parameterized quantum circuit. Here, for ease of description, the qubits in Alice's laboratory are written as: quantum bit AiI ═ 1,2, …, n; qubits in Bob laboratories are noted: quantum bit BiI is 1,2, …, b, wherein AiAnd BiIntertwined with each other, and belong to a quantum system. Further, this example is for qubit a in an entangled state and in the same system1And B1Initial quantum state pABAnd (5) carrying out purification treatment.
Step 2: alice parameterizes quantum circuit
Acting on n qubits corresponding to themselves, i.e. on qubit Ai1,2, …, n; similarly, Bob parameterizes quantitiesSub-circuit
Acting on its own corresponding n qubits, i.e. on qubit BiAnd i is 1,2, …, n.
Here, it should be noted that, in the process of the actual local quantum operation, Alice may apply the parameterized quantum circuit to some of the n qubits corresponding to Alice, rather than to all the qubits; similarly, Bob may apply the parameterized qubit to some of the n qubits corresponding to Bob, rather than to all the qubits, as long as the qubits selected to be applied by Bob are in an entangled state; for example, suppose Alice selects qubit A from n qubits2，A4，A7And parameterizing the quantum circuit
Acting on qubit A2，A4，A7At this time, with A2The qubit in the entangled state is B2And A is4The qubit in the entangled state is B4And A is7The qubit in the entangled state is B7Therefore, at this time, Bob also needs to select qubit a from n qubits corresponding to Bob itself2，A4，A7Corresponding to B2，B4，B7And parameterizing the quantum circuit
Acting on qubit B2，B4，B7。
And step 3: parameterized quantum circuit for Alice measurement
Last qubit A2Quantum bit A3… qubit AnI.e. the middle component of n-1 qubitsObtaining the state information of the sub-bits to obtain a measurement result A; similarly, Bob measurement parameterized quantum circuit
Last qubit B2Quantum bit B3… qubit BnI.e., the state information of a portion of the qubits in n-1 qubits, to obtain measurement result B. That is, Alice and Bob each divide the initial quantum state ρ to be purifiedABCorresponding qubit A1And B1Some of the other qubits are measured. Then, Alice and Bob exchange the measurement results obtained by the respective measurements in a classical communication mode.
Here, note that, in this step, for both Alice and Bob, only the initial quantum state ρ to be subjected to the purification process may be dividedABCorresponding qubit A1And B1Other parts of the qubit than the one above are subjected to local quantum measurement, provided that, after all cycles have ended, the qubit a can be subjected to local quantum measurement on the other parts of the qubit than the qubit a1And B1And all the other qubits are required to complete local quantum measurement. Specifically, for the round number N equal to 1, Alice and Bob in this step both need to divide qubit a separately1And B1And performing local quantum measurement on all the remaining qubits, and obtaining corresponding measurement results. And when N is more than or equal to 2, in the step, Alice and Bob only need to divide the qubit A by each pair1And B1And local quantum measurement is performed on the remaining part of the qubits, which is not limited in the present application. Certainly, in one implementation process, Alice and/or Bob may also not perform measurement, and perform local quantum measurement again in the next cycle, which is not limited in the present application.
And 4, step 4: after information exchange, under the condition that Alice and Bob determine that the relationship between the measurement result A and the measurement result B meets the preset condition according to the own measurement result and the measurement result of the other party, other parameterized quantum circuits matched with the measurement result A and the measurement result B are selected and applied to the corresponding quantum bits again according to the mode.
Here, it should be noted that the present example can also obtain a probability that a preset condition is met, and further, a probability that a subsequent LOCC operation is given can be provided, so that quantifiable data support is provided for entanglement conversion in an actual scene. For example, if the measurement result a is the same as the measurement result B, the predetermined condition is satisfied, and the present disclosure can provide a probability that the measurement result a is the same as the measurement result B. Of course, the preset condition may be determined based on the actual requirement of the actual scene, which is not limited by the present application.
And 5: repeating the steps 2-4, N-1 times, namely obtaining a LOCC operation after completing N times of communication, wherein a purified quantum state rho 'is output'ABI.e. the purified quantum state ρ'ABNamely the qubit A to be purified1And B1Initial quantum state rho of corresponding quantum systemABAnd purifying to obtain an entangled quantum state.
Here, it should be noted that, in the above repeatedly executed process, the qubit selected and acted each time in step 2 may be the same as or different from the qubit in the last execution process, and this is not limited in the present application. For example, in step 2, the qubit that Alice selects to act on the parameterized quantum circuit in one execution process may be qubit a2，A4，A7Bob selects the qubit to be applied to the parameterized quantum circuit to be qubit B2，B4，B7(ii) a At this time, in the next cycle, the qubit that Alice chooses to act on the parameterized quantum circuit may be qubit a5，A6，A7，A10The qubits that Bob chooses to act on the parameterized quantum circuit are accordingly qubits B5，B6，B7，B10The qubits selected to be acted upon in the two processes are different, and as shown in fig. 3, the qubits selected to be acted upon by different parameterized quantum circuits may be the same or different.
Step 6: calculating purified quantum state rho'ABAnd target Bell state phi+Inter-fidelity Tr (phi)+ρ′AB) And the loss function L is 1-Tr (phi)+ρ′AB)。
And 7: adjusting parameters, e.g. alpha, in parameterized quantum circuits used in the above implementation by gradient descent or other optimization methods1And β1And repeating steps 2-6 to minimize the loss function L.
And 8: when the loss function L is minimized, then the parameterized quantum circuits used in the above process, e.g.
And
the parameters in the quantum state are optimized, and the target purified quantum state can be obtained after the parameters are optimized
Outputting optimized parameters, and adding the quantum measurement and information exchange results in the above steps to obtain the initial quantum state rhoABPurification into target purified quantum states
The LOCC operating scheme of (1). In particular, compared to the initial quantum state ρABTarget purification of quantum states
The fidelity to the target bell state is higher.
Here, it should be noted that the above-mentioned schemes can be realized in a simulation manner on a classical device, such as a classical computer, and after the LOCC operation scheme is obtained by a classical computer simulation, the actual operation can be performed on a quantum device, so as to realize entanglement purification.
Thus, compared with the existing scheme, the scheme of the application has the advantages of applicability, high efficiency, practicability, expansibility and universality. Here, the applicability means that the scheme of the application is not limited to the bell diagonal state, and the entangled quantum state containing general noise can be purified; the high efficiency means that the state obtained by purification in the scheme of the application has higher fidelity; the practicability means that the LOCC operation scheme obtained by the scheme can be realized on recent quantum equipment; the expansibility means that the scheme can distill and purify n-copies qubit entanglement pairs; the commonality pointer all can realize high-efficient purification to different situations, such as single communication protocol, many communication protocol, single round of distillation, many rounds of distillation and other special cases through simple modification to this application scheme.
In order to further verify the scheme of the application, an experiment for performing entanglement distillation on 2-copy (2 quantum bit entangled pairs) entangled states (namely initial quantum states) with random noise is given, and the number of communication rounds between Alice and Bob is 1; here, the specific form of the initial quantum state is:
ρ(p)＝pΦ++(1-p)ρrand；
wherein phi+Is one of four Bell states, and the matrix form is:
here, ρrandIs a randomly generated matrix representing a quantum state that represents the background noise in the experiment. By training the parameterized quantum circuit, we can obtain the fidelity after purification, as shown in the following table:
| parameters of isotropic behavior p | Fidelity of initial state | BBPSSW | DEJMPS | This scheme |
| 0.4 | 0.504191444 | 0.493814 | 0.503944 | 0.5198 |
| 0.5 | 0.586826204 | 0.589634 | 0.607636 | 0.65309 |
| 0.6 | 0.669460963 | 0.683678 | 0.704896 | 0.74793 |
| 0.7 | 0.752095722 | 0.772854 | 0.792788 | 0.868819 |
| 0.8 | 0.834730481 | 0.855458 | 0.870621 | 0.934414 |
| 0.9 | 0.917365241 | 0.931039 | 0.939195 | 0.976485 |
From the above comparison, it can be seen that the scheme of the present application can purify entangled states with higher fidelity than the fidelity obtained by the existing schemes (e.g., BBPSSW and DEJMPS).
Here, in practical use, a parameterized quantum circuit U is preparedAAnd UBIn time, multiple schemes may be selected to address different situations:
first, using parameterized quantum circuits UAAnd UBIt can be easily extended to n quantum bit entangled pairs.
Secondly, a unidirectional communication protocol can be flexibly used, namely Alice informs Bob of the measurement result, but Bob does not need to inform Alice of the own result, or a bidirectional communication protocol, namely Alice and Bob mutually inform the own measurement result, so that the parameterized quantum circuit U is selectedAAnd UB。
Third, the parameterized quantum circuit U may also be selected based on the number of distillation rounds required, i.e., NAAnd UB。
Fourth, the exemplary scheme is described as n->1, namely n parts of the input initial quantum state, and purifying to obtain a purified quantum state. However, it is also possible to>m, i.e. n parts of the input initial quantum state, and m purified quantum states are obtained through purification. Here, the n quantum states of the input initial quantum states may also be different, and the parameterized quantum circuit U is selected based on this requirementAAnd UB。
To sum up, the scheme of the application has the following advantages:
first, the application scope of the scheme of this application is wider than the existing scheme.
Second, compared with the existing scheme, the method and the device for purifying the entangled state containing the common noise are not limited to the isotropic state or the Bell diagonal state, and have strong universality.
Thirdly, the scheme of the application has high efficiency, namely the fidelity of the purification scheme of the LOCC operation obtained by machine learning optimization is higher than that of the existing scheme.
Fourth, this application scheme has the practicality, owing to adopted parameterization quantum circuit, its nimble, various structure makes this application scheme have very strong expansibility and adaptability, can be directed against different application scenes and the suitable scheme of quantum equipment design.
The present application further provides an entangled quantum state purification apparatus, as shown in fig. 4, including:
a qubit group obtaining unit 401, configured to determine a first group of qubits and a second group of qubits, where the first group of qubits includes n first qubits and the second group of qubits includes n second qubits;
a first parameterized quantum circuit processing unit 402, configured to apply a first parameterized quantum circuit corresponding to the first group of qubits to at least part of first qubits in the first group of qubits and obtain state information of part of other first qubits, except for a target first qubit, in the first group of qubits after the first parameterized quantum circuit is applied, so as to obtain a first measurement result;
a second parameterized quantum circuit processing unit 403, configured to apply a second parameterized quantum circuit corresponding to the second set of qubits to at least part of second qubits in the second set of qubits and obtain state information of part of other second qubits, except for a target second qubit, in the second set of qubits after the second parameterized quantum circuit is applied, so as to obtain a second measurement result, where the target second qubit is a qubit entangled with the target first qubit;
a refining processing unit 404, configured to perform refining processing on entangled quantum states corresponding to the target first qubit and the target second qubit based on at least a relationship between the first measurement result and the second measurement result, and obtain a target refined quantum state.
In a specific example of the scheme of the present application, the method further includes:
the device comprises a qubit entanglement pair processing unit, a processing unit and a processing unit, wherein the qubit entanglement pair processing unit is used for determining n groups of qubit entanglement pairs, and the qubit entanglement pairs comprise at least two mutually entangled qubits; splitting at least two qubits included in the qubit entanglement pair into at least two groups of qubits to obtain a first group of qubits and a second group of qubits, wherein the first group of qubits includes n first qubits in the qubit entanglement pair, and the second group of qubits includes n second qubits in the qubit entanglement pair.
In a specific example of the scheme of the present application, the method further includes:
and a target qubit entanglement pair selection unit, configured to select a target qubit entanglement pair for performing a refinement process from the n sets of qubit entanglement pairs, where the target first qubit and the target second qubit are mutually entangled qubits in the target qubit entanglement pair.
In a specific example of the solution of the present application, the second parameterized quantum circuit processing unit is further configured to select, from the second group of qubits, a second qubit entangled with the first qubit acted on by the first parameterized quantum circuit; and applying a second parameterized quantum circuit corresponding to the second group of quantum bits to the selected second quantum bit entangled with the first quantum bit acted by the first parameterized quantum circuit.
In a specific example of the solution of the present application, the first parameterized quantum circuit processing unit is further configured to, in a case that it is determined that a relationship between the first measurement result and the second measurement result satisfies a preset condition, select a new first parameterized quantum circuit that matches the first measurement result and the second measurement result, apply the new first parameterized quantum circuit to at least a part of first qubits in the first group of qubits to obtain a new first measurement result, and update the first measurement result, so as to loop until a preset number of loops is reached;
the second parameterized quantum circuit processing unit is further configured to, when it is determined that the relationship between the first measurement result and the second measurement result satisfies a preset condition, select a new second parameterized quantum circuit that matches the first measurement result and the second measurement result, apply the new second parameterized quantum circuit to at least a part of second qubits in a second group of qubits to obtain a new second measurement result, and update the second measurement result, so as to loop until a preset number of loops is reached;
the purifying processing unit is further configured to perform purifying processing on entangled quantum states corresponding to the target first qubit and the target second qubit based on the updated relationship between the first measurement result and the second measurement result, and obtain a target purified quantum state.
In a specific example of the present application, the refining processing unit is further configured to obtain a refined quantum state between the target first qubit and the target second qubit when it is determined that a relationship between the first measurement result and the second measurement result satisfies a preset condition; and adjusting the parameters of the first parameterized quantum circuit and the parameters of the second parameterized quantum circuit based on the difference between the purified quantum state and the target quantum state so as to purify the entangled quantum states corresponding to the target first quantum bit and the target second quantum bit and obtain the target purified quantum state.
In a specific example of the present application, the target quantum state belongs to a bayer state.
In a specific example of the present application, the purification processing unit is further configured to, after the parameter adjustment, determine that the obtained fidelity between the purified quantum state and the target quantum state satisfies a preset rule, use the purified quantum state corresponding to the preset rule as the target purified quantum state.
In a specific example of the present application, the purification processing unit is further configured to determine a fidelity between the obtained purified quantum state and the target quantum state, and obtain a loss function based on the fidelity; and minimizing the loss function in a parameter adjustment mode, and taking the purification quantum state when the loss function is at the minimum value as the target purification quantum state.
The functions of each unit in the entangled quantum state purification device in the embodiment of the present invention can be referred to the corresponding description in the above method, and are not described herein again.
Here, it should be noted that the entangled quantum state purifying apparatus according to the present disclosure may be a classical device, such as a classical computer, a classical electronic device, and the like, in which case, the above units may be implemented by hardware of the classical device, such as a memory, a processor, and the like. Of course, the entangled quantum state purification device in the present application may also be a quantum device, in which case, each unit may be implemented by quantum hardware or the like.
The present disclosure also provides an electronic device, a readable storage medium, and a computer program product according to embodiments of the present disclosure.
FIG. 5 illustrates a schematic block diagram of an example computing device 500 that can be used to implement embodiments of the present disclosure. Electronic devices are intended to represent various forms of digital computers, such as laptops, desktops, workstations, personal digital assistants, servers, blade servers, mainframes, and other appropriate computers. The electronic device may also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions, are meant to be examples only, and are not meant to limit implementations of the disclosure described and/or claimed herein.
As shown in fig. 5, the device 500 comprises a computing unit 501 which may perform various suitable actions and processes in accordance with a computer program stored in a Read Only Memory (ROM)502 or a computer program loaded from a storage unit 508 into a Random Access Memory (RAM) 503. In the RAM503, various programs and data required for the operation of the device 500 can also be stored. The calculation unit 501, the ROM502, and the RAM503 are connected to each other by a bus 504. An input/output (I/O) interface 505 is also connected to bus 504.
A number of components in the device 500 are connected to the I/O interface 505, including: an input unit 506 such as a keyboard, a mouse, or the like; an output unit 507 such as various types of displays, speakers, and the like; a storage unit 508, such as a magnetic disk, optical disk, or the like; and a communication unit 509 such as a network card, modem, wireless communication transceiver, etc. The communication unit 509 allows the device 500 to exchange information/data with other devices through a computer network such as the internet and/or various telecommunication networks.
The computing unit 501 may be a variety of general-purpose and/or special-purpose processing components having processing and computing capabilities. Some examples of the computing unit 501 include, but are not limited to, a Central Processing Unit (CPU), a Graphics Processing Unit (GPU), various dedicated Artificial Intelligence (AI) computing chips, various computing units running machine learning model algorithms, a Digital Signal Processor (DSP), and any suitable processor, controller, microcontroller, and so forth. The computing unit 501 performs the various methods and processes described above, such as an entangled quantum state purification method. For example, in some embodiments, the entangled quantum state purification method may be implemented as a computer software program tangibly embodied in a machine-readable medium, such as storage unit 508. In some embodiments, part or all of the computer program may be loaded and/or installed onto the device 500 via the ROM502 and/or the communication unit 509. When the computer program is loaded into RAM503 and executed by computing unit 501, one or more steps of the entangled quantum state purification method described above may be performed. Alternatively, in other embodiments, the computing unit 501 may be configured to perform the entangled quantum state purification method by any other suitable means (e.g., by means of firmware).
Various implementations of the systems and techniques described here above may be implemented in digital electronic circuitry, integrated circuitry, Field Programmable Gate Arrays (FPGAs), Application Specific Integrated Circuits (ASICs), Application Specific Standard Products (ASSPs), system on a chip (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and/or combinations thereof. These various embodiments may include: implemented in one or more computer programs that are executable and/or interpretable on a programmable system including at least one programmable processor, which may be special or general purpose, receiving data and instructions from, and transmitting data and instructions to, a storage system, at least one input device, and at least one output device.
Program code for implementing the methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowchart and/or block diagram to be performed. The program code may execute entirely on the machine, partly on the machine, as a stand-alone software package partly on the machine and partly on a remote machine or entirely on the remote machine or server.
In the context of this disclosure, a machine-readable medium may be a tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. The machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of a machine-readable storage medium would include an electrical connection based on one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.
To provide for interaction with a user, the systems and techniques described here can be implemented on a computer having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to a user; and a keyboard and a pointing device (e.g., a mouse or a trackball) by which a user can provide input to the computer. Other kinds of devices may also be used to provide for interaction with a user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user may be received in any form, including acoustic input, speech input, or tactile input.
The systems and techniques described here can be implemented in a computing system that includes a back-end component (e.g., as a data server), or that includes a middleware component (e.g., an application server), or that includes a front-end component (e.g., a user computer having a graphical user interface or a web browser through which a user can interact with an implementation of the systems and techniques described here), or any combination of such back-end, middleware, or front-end components. The components of the system can be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: local Area Networks (LANs), Wide Area Networks (WANs), and the Internet.
The computer system may include clients and servers. A client and server are generally remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other.
It should be understood that various forms of the flows shown above may be used, with steps reordered, added, or deleted. For example, the steps described in the present disclosure may be executed in parallel or sequentially or in different orders, and are not limited herein as long as the desired results of the technical solutions disclosed in the present disclosure can be achieved.
The above detailed description should not be construed as limiting the scope of the disclosure. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions may be made in accordance with design requirements and other factors. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present disclosure should be included in the scope of protection of the present disclosure.
Claims (16)
1. A method of purifying entangled quantum states, comprising:
determining a first group of qubits and a second group of qubits, wherein the first group of qubits includes n first qubits and the second group of qubits includes n second qubits;
applying a first parameterized quantum circuit corresponding to the first group of qubits to at least part of first qubits in the first group of qubits, and obtaining state information of part other first qubits except the target first qubit in the first group of qubits after the first parameterized quantum circuit is applied, so as to obtain a first measurement result;
applying a second parameterized quantum circuit corresponding to the second group of qubits to at least part of second qubits in the second group of qubits, and obtaining state information of other second qubits in the second group of qubits after the second parameterized quantum circuit is applied, except for a target second qubit, so as to obtain a second measurement result, wherein the target second qubit is a qubit entangled with the target first qubit, and the first and second parameterized quantum circuits both include a single-qubit rotating gate and a CNOT gate, and both use vectors formed by rotation angles as adjustable parameters;
performing a purification process on entangled quantum states corresponding to the target first qubit and the target second qubit based on at least a relationship between the first measurement result and the second measurement result, and obtaining a target purified quantum state, including:
obtaining a purified quantum state between the target first qubit and the target second qubit when determining that the relationship between the first measurement result and the second measurement result satisfies a preset condition;
and adjusting the parameters of the first parameterized quantum circuit and the parameters of the second parameterized quantum circuit based on the difference between the purified quantum state and the target quantum state, and taking the purified quantum state corresponding to the purified quantum state meeting the preset rule as the target purified quantum state under the condition that the fidelity between the purified quantum state and the target quantum state meets the preset rule after the parameters are adjusted.
2. The method of claim 1, further comprising:
determining n groups of quantum bit entangled pairs, wherein the quantum bit entangled pairs comprise at least two quantum bits entangled with each other;
splitting at least two qubits included in the qubit entanglement pair into at least two groups of qubits to obtain a first group of qubits and a second group of qubits, wherein the first group of qubits includes n first qubits in the qubit entanglement pair, and the second group of qubits includes n second qubits in the qubit entanglement pair.
3. The method of claim 2, further comprising:
and selecting a target qubit entanglement pair for purification from the n groups of qubit entanglement pairs, wherein the target first qubit and the target second qubit are mutually entangled qubits in the target qubit entanglement pair.
4. The method of claim 1, further comprising: selecting a second qubit from the second set of qubits that is intertwined with the first qubit acted on by the first parameterized quantum circuit;
wherein said applying a second parameterized quantum circuit corresponding to the second set of qubits to at least some of the second qubits in the second set of qubits comprises:
and applying a second parameterized quantum circuit corresponding to the second group of quantum bits to the selected second quantum bit entangled with the first quantum bit acted by the first parameterized quantum circuit.
5. The method of any of claims 1 to 4, further comprising:
under the condition that the relation between the first measurement result and the second measurement result is determined to meet a preset condition, selecting a new first parameterized quantum circuit matched with the first measurement result and the second measurement result, applying the new first parameterized quantum circuit to at least part of first qubits in a first group of qubits to obtain a new first measurement result, and updating the first measurement result; selecting a new second parameterized quantum circuit matched with the first measurement result and the second measurement result, applying the new second parameterized quantum circuit to at least part of second qubits in a second group of qubits to obtain a new second measurement result, and updating the second measurement result, so as to circulate until a preset circulation frequency is reached;
wherein the purifying the entangled quantum states corresponding to the target first qubit and the target second qubit based on at least the relationship between the first measurement result and the second measurement result to obtain a target purified quantum state further comprises:
and based on the updated relationship between the first measurement result and the second measurement result, purifying the entangled quantum states corresponding to the target first quantum bit and the target second quantum bit, and obtaining a target purified quantum state.
6. The method of claim 1, wherein the target quantum state belongs to a bell state.
7. The method of claim 1, further comprising:
determining fidelity between the obtained purified quantum state and the target quantum state, and obtaining a loss function based on the fidelity;
and minimizing the loss function in a parameter adjustment mode, and taking the purification quantum state when the loss function is at the minimum value as the target purification quantum state.
8. An entangled quantum state purification device comprising:
the apparatus comprises a qubit group obtaining unit, a qubit group obtaining unit and a qubit group obtaining unit, wherein the qubit group obtaining unit is used for determining a first group of qubits and a second group of qubits, the first group of qubits comprises n first qubits, and the second group of qubits comprises n second qubits;
the first parameterized quantum circuit processing unit is used for applying a first parameterized quantum circuit corresponding to the first group of qubits to at least part of first qubits in the first group of qubits and obtaining state information of part of other first qubits except the target first qubit in the first group of qubits after the first parameterized quantum circuit is applied to the first group of qubits so as to obtain a first measurement result;
a second parameterized quantum circuit processing unit, configured to apply a second parameterized quantum circuit corresponding to the second group of qubits to at least part of second qubits in the second group of qubits, and obtain state information of part of other second qubits, except for a target second qubit, in the second group of qubits after the second parameterized quantum circuit is applied, so as to obtain a second measurement result, where the target second qubit is a qubit entangled with the target first qubit, and each of the first and second parameterized quantum circuits includes a single-qubit rotation gate and a CNOT gate, and uses a vector formed by rotation angles as an adjustable parameter;
a purification processing unit, configured to perform purification processing on entangled quantum states corresponding to the target first qubit and the target second qubit based on at least a relationship between the first measurement result and the second measurement result, and obtain a target purified quantum state, and specifically configured to:
obtaining a purified quantum state between the target first qubit and the target second qubit when determining that the relationship between the first measurement result and the second measurement result satisfies a preset condition;
and adjusting the parameters of the first parameterized quantum circuit and the parameters of the second parameterized quantum circuit based on the difference between the purified quantum state and the target quantum state, and taking the purified quantum state corresponding to the purified quantum state meeting the preset rule as the target purified quantum state under the condition that the fidelity between the purified quantum state and the target quantum state meets the preset rule after the parameters are adjusted.
9. The apparatus of claim 8, further comprising:
the device comprises a qubit entanglement pair processing unit, a processing unit and a processing unit, wherein the qubit entanglement pair processing unit is used for determining n groups of qubit entanglement pairs, and the qubit entanglement pairs comprise at least two mutually entangled qubits; splitting at least two qubits included in the qubit entanglement pair into at least two groups of qubits to obtain a first group of qubits and a second group of qubits, wherein the first group of qubits includes n first qubits in the qubit entanglement pair, and the second group of qubits includes n second qubits in the qubit entanglement pair.
10. The apparatus of claim 9, further comprising:
and a target qubit entanglement pair selection unit, configured to select a target qubit entanglement pair for performing a refinement process from the n sets of qubit entanglement pairs, where the target first qubit and the target second qubit are mutually entangled qubits in the target qubit entanglement pair.
11. The apparatus of claim 8, wherein the second parameterized quantum circuit processing unit is further configured to select a second qubit from the second set of qubits that is entangled with the first qubit acted on by the first parameterized quantum circuit; and applying a second parameterized quantum circuit corresponding to the second group of quantum bits to the selected second quantum bit entangled with the first quantum bit acted by the first parameterized quantum circuit.
12. The apparatus of any one of claims 8 to 11,
the first parameterized quantum circuit processing unit is further configured to, when it is determined that the relationship between the first measurement result and the second measurement result satisfies a preset condition, select a new first parameterized quantum circuit that matches the first measurement result and the second measurement result, apply the new first parameterized quantum circuit to at least a part of first qubits in the first group of qubits to obtain a new first measurement result, and update the first measurement result, so as to loop until a preset number of loops is reached;
the second parameterized quantum circuit processing unit is further configured to, when it is determined that the relationship between the first measurement result and the second measurement result satisfies a preset condition, select a new second parameterized quantum circuit that matches the first measurement result and the second measurement result, apply the new second parameterized quantum circuit to at least a part of second qubits in a second group of qubits to obtain a new second measurement result, and update the second measurement result, so as to loop until a preset number of loops is reached;
the purifying processing unit is further configured to perform purifying processing on entangled quantum states corresponding to the target first qubit and the target second qubit based on the updated relationship between the first measurement result and the second measurement result, and obtain a target purified quantum state.
13. The apparatus of claim 8, wherein the target quantum state belongs to a bell state.
14. The apparatus of claim 8, wherein the purification processing unit is further configured to determine a fidelity between the obtained purified quantum state and the target quantum state, and to derive a loss function based on the fidelity; and minimizing the loss function in a parameter adjustment mode, and taking the purification quantum state when the loss function is at the minimum value as the target purification quantum state.
15. An electronic device, comprising:
at least one processor; and
a memory communicatively coupled to the at least one processor; wherein the content of the first and second substances,
the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the method of any one of claims 1-7.
16. A non-transitory computer readable storage medium having stored thereon computer instructions for causing a computer to perform the method of any one of claims 1-7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011541607.2A CN112529199B (en) | 2020-12-23 | 2020-12-23 | Entangled quantum state purification method, device, equipment, storage medium and product |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011541607.2A CN112529199B (en) | 2020-12-23 | 2020-12-23 | Entangled quantum state purification method, device, equipment, storage medium and product |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112529199A CN112529199A (en) | 2021-03-19 |
| CN112529199B true CN112529199B (en) | 2021-09-28 |
Family
ID=74975934
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011541607.2A Active CN112529199B (en) | 2020-12-23 | 2020-12-23 | Entangled quantum state purification method, device, equipment, storage medium and product |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112529199B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112529198B (en) * | 2020-12-23 | 2021-10-01 | 北京百度网讯科技有限公司 | Quantum entanglement state processing method, device, equipment, storage medium and product |
| CN115276823B (en) * | 2022-07-22 | 2024-01-16 | 上海海事大学 | High-fidelity entangled link generation method based on quantum space time |
| CN116346334B (en) * | 2023-03-20 | 2024-02-02 | 北京百度网讯科技有限公司 | Distillable key estimation method, apparatus, device and storage medium |
Family Cites Families (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7310623B2 (en) * | 2003-12-12 | 2007-12-18 | Hewlett-Packard Development Company, L.P. | Games using pair-wise entanglements |
| JP4162687B2 (en) * | 2006-06-09 | 2008-10-08 | 株式会社東芝 | Quantum information communication system, quantum information relay device, quantum information communication method and program |
| CN102130769A (en) * | 2011-03-10 | 2011-07-20 | 北京邮电大学 | Model and method for realizing request control and automatic implementation of quantum key distribution (QKD) |
| CN102724036B (en) * | 2012-06-04 | 2015-01-14 | 上海交通大学 | Continuous variable quantum key distribution system and synchronous realization method thereof |
| CN103684743B (en) * | 2013-12-06 | 2017-01-11 | 苏州大学 | Multi-party control quantum steganography method based on non-maximally entanglement channel and signal reassignment technology |
| CN104104503B (en) * | 2014-07-22 | 2017-07-21 | 浙江工商大学 | The fault tolerant single channel encryption quantum dialogue method of phase noise moves back in anti-collective |
| CN104466655B (en) * | 2014-12-25 | 2017-12-29 | 华南师范大学 | Polarize the generation system and method for orbital angular momentum mixing Entangled State single photon |
| US10554312B2 (en) * | 2018-05-14 | 2020-02-04 | The United States Of America As Represented By The Secretary Of The Army | Method and system for measuring interferometric visibility of telescopic signals having imperfect quantum entanglement |
| CN108847939B (en) * | 2018-10-09 | 2020-02-21 | 南京南瑞国盾量子技术有限公司 | MDI-QKD method based on quantum network |
| WO2020077303A1 (en) * | 2018-10-12 | 2020-04-16 | Lucarelli Dennis | System and methods for quantum post-selection using logical parity encoding and decoding |
| CN113330466A (en) * | 2018-11-19 | 2021-08-31 | Qm威尔股份公司 | Systems and methods involving aspects and/or other features of hybrid quantum machines, quantum information techniques |
| CN110472739B (en) * | 2019-08-12 | 2021-08-24 | 北京中创为南京量子通信技术有限公司 | Efficient post-processing method and device for quantum random number and quantum random number generator |
| CN111738448B (en) * | 2020-06-23 | 2021-09-28 | 北京百度网讯科技有限公司 | Quantum line simulation method, device, equipment and storage medium |
| CN111882068B (en) * | 2020-06-29 | 2022-03-18 | 北京百度网讯科技有限公司 | Method, device, equipment and medium for eliminating noise influence of QOA quantum circuit |
-
2020
- 2020-12-23 CN CN202011541607.2A patent/CN112529199B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN112529199A (en) | 2021-03-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112529199B (en) | Entangled quantum state purification method, device, equipment, storage medium and product | |
| CN112529198B (en) | Quantum entanglement state processing method, device, equipment, storage medium and product | |
| CN112529201B (en) | Entangled quantum state conversion method, device, equipment, storage medium and product | |
| CN112529200B (en) | Entangled quantum state purification method, device, equipment, storage medium and product | |
| CN112529202B (en) | Quantum entanglement state distribution method, device, equipment, storage medium and product | |
| CN113011593B (en) | Method and system for eliminating quantum measurement noise, electronic device and medium | |
| CN109788489B (en) | Base station planning method and device | |
| CN114374440B (en) | Quantum channel classical capacity estimation method and device, electronic equipment and medium | |
| WO2017088587A1 (en) | Data processing method and device | |
| CN111667018B (en) | Object clustering method and device, computer readable medium and electronic equipment | |
| Mancino-Ball et al. | A decentralized primal-dual framework for non-convex smooth consensus optimization | |
| CN114091686B (en) | Data processing method and device, electronic equipment and storage medium | |
| CN116346334B (en) | Distillable key estimation method, apparatus, device and storage medium | |
| CN116405200B (en) | Distillable key estimation method, apparatus, device and storage medium | |
| CN114418107B (en) | Unitary operator compiling method, computing device, unitary operator compiling apparatus and storage medium | |
| CN115941059B (en) | Quantum communication realization method and device, electronic equipment and medium | |
| WO2022259481A1 (en) | Learning method | |
| CN113762510B (en) | Data processing method and device for target model, electronic equipment and medium | |
| WO2024066791A1 (en) | Data processing method, apparatus and system, and medium and program product | |
| US20220398416A1 (en) | System and method for identifying approximate k-nearest neighbors in web scale clustering | |
| CN117669751A (en) | Quantum circuit simulation method and device and electronic equipment | |
| CN113065661A (en) | Quantum state measurement method, device, equipment, storage medium and system | |
| CN118036755A (en) | Quantification method, device, equipment and medium of large language model | |
| CN114862037A (en) | Solving method and solving method of power generation cost optimization function | |
| CN116402147A (en) | Quantum device performance comparison method and device, electronic device and medium |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |