Method, device, computer equipment and storage medium for preparing exponentially distributed quantum states

Abstract

The embodiments of this specification provide a method for preparing an exponentially distributed quantum state. The method includes: obtaining a first preset parameter and a second preset parameter; wherein the first preset parameter is used to represent the distribution law of the exponential distribution; the second preset parameter is used to represent the accuracy of the preparation of the exponentially distributed quantum state; based on the first preset parameter and the second preset parameter, determining the number m of quantum bits used to prepare the exponentially distributed quantum state; performing an RY gate operation with a specified parameter on each of the m quantum bits in the initial state to obtain a target quantum state representing the exponential distribution; wherein the specified parameter is determined based on the first preset parameter and the second preset parameter; and the specified parameters corresponding to the RY gate operation performed on different quantum bits are different. This allows the preparation of an exponentially distributed quantum state to be achieved without entanglement between the m quantum bits, and the quantum circuit depth is relatively shallow, which enhances the stability of the quantum circuit operation.

Description

Technical Field

[0001] The embodiments in this specification relate to the field of quantum computing, and specifically to a method, apparatus, computer device, and storage medium for preparing an exponentially distributed quantum state. Background Art

[0002] Exponential distributions are widely used in finance and other fields. Therefore, a universal method for preparing exponentially distributed quantum states is crucial for applying quantum computing to specific problems. Because the properties of exponential distributions, in principle, effectively match quantum states, they can be prepared using quantum amplitudes.

[0003] Currently, the preparation of exponentially distributed quantum states can generally be achieved using general algorithms, such as the Grover algorithm. However, when using these general algorithms to accurately prepare exponentially distributed quantum states, the decoherence effect of the quantum system can lead to low stability during the operation of the quantum circuit used to prepare the exponentially distributed quantum state. Summary of the Invention

[0004] In view of this, multiple embodiments of this specification are dedicated to providing a method, apparatus, computer device, and storage medium for preparing an exponentially distributed quantum state, so as to prevent quantum decoherence effects to a certain extent, thereby improving the stability of quantum circuit operation, and thus improving the stability and reliability of the prepared exponentially distributed quantum state.

[0005] Multiple embodiments in this specification provide a method for preparing an exponentially distributed quantum state, the method comprising: obtaining a first preset parameter and a second preset parameter; wherein the first preset parameter is used to represent the distribution law of the exponential distribution; the second preset parameter is used to represent the accuracy of the preparation of the exponentially distributed quantum state; based on the first preset parameter and the second preset parameter, determining the number m of quantum bits used to prepare the exponentially distributed quantum state; performing a RY gate operation with a specified parameter on each of the m quantum bits in the initial state to obtain a target quantum state for representing the exponential distribution; wherein the specified parameter is determined based on the first preset parameter and the second preset parameter; and the specified parameters corresponding to the RY gate operation performed on different quantum bits are different.

[0006] One embodiment of the present specification provides an apparatus for preparing an exponentially distributed quantum state, the apparatus comprising: an acquisition module; used to acquire a first preset parameter and a second preset parameter; wherein the first preset parameter is used to represent the distribution law of the exponential distribution; the second preset parameter is used to represent the accuracy of the preparation of the exponentially distributed quantum state; a determination module; used to determine the number m of quantum bits used to prepare the exponentially distributed quantum state based on the first preset parameter and the second preset parameter; an execution module; used to perform an RY gate operation with a specified parameter on each of the m quantum bits in an initial state to obtain a target quantum state representing the exponential distribution; wherein the specified parameter is determined based on the first preset parameter and the second preset parameter; and the specified parameters corresponding to the RY gate operation performed on different quantum bits are different.

[0007] The embodiments of this specification provide a computer device including a memory and a processor. The memory stores a computer program, and the processor implements the method described in the above embodiments when executing the computer program.

[0008] The embodiments of this specification provide a computer-readable storage medium having computer program instructions stored thereon. When the program is executed by a processor, the method described in the above embodiments is implemented.

[0009] The multiple embodiments provided in this specification obtain a first preset parameter for representing the distribution law of the exponential distribution and a second preset parameter for representing the preparation accuracy. Then, based on the first and second preset parameters, the number m of qubits used to prepare the exponentially distributed quantum state is determined. Then, an RY gate operation with specified parameters is performed on each of the m qubits in the initial state to obtain a target quantum state representing the exponential distribution. The specified parameters are determined based on the first and second preset parameters, and the specified parameters corresponding to the RY gate operation performed on different qubits are different. By applying a RY gate with specified parameters to each qubit used for quantum state preparation, a target quantum state representing the exponential distribution is obtained. This allows the m qubits in the embodiments of this specification to be prepared without quantum entanglement, and the quantum circuit depth is relatively shallow, so that the preparation of the exponentially distributed quantum state can be achieved. To a certain extent, the operation and measurement of the quantum circuit can maintain a high degree of stability, further improving the reliability and stability of the prepared exponentially distributed quantum state. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 A schematic diagram of a method for preparing an exponentially distributed quantum state provided in accordance with one embodiment of this specification.

[0011] Figure 2A schematic diagram of a quantum circuit for preparing an exponentially distributed quantum state is provided for one embodiment of this specification.

[0012] Figure 3 A schematic diagram of measurement results of a quantum circuit for preparing an exponentially distributed quantum state, provided for one embodiment of this specification.

[0013] Figure 4 A schematic diagram of an apparatus for preparing an exponentially distributed quantum state according to one embodiment of this specification.

[0014] Figure 5 A schematic diagram of a computer device provided for one embodiment of the present specification. DETAILED DESCRIPTION

[0015] Quantum computing can be used to solve some problems involving probability distribution calculations. For example, asset pricing or risk estimation often requires simulating and predicting future asset prices and their fluctuations, processes that often involve calculating probability distributions. Quantum computing can help solve these problems by achieving computations faster than classical computers. The exponential distribution, as a widely used probability distribution model, holds important implications for using quantum computing to solve problems involving probability distribution calculations. For example, using exponentially distributed quantum states to simulate classical random processes can more accurately estimate asset price volatility and predict and evaluate future asset prices. Furthermore, the exponential distribution can be used in Monte Carlo methods for quantum simulation to more accurately estimate financial risk and probability. Therefore, preparing exponentially distributed quantum states can help users process and solve these problems more quickly.

[0016] At present, to achieve the preparation of exponentially distributed quantum states, it is usually necessary to perform amplitude encoding on any state. For example, using the Grover algorithm to prepare any quantum initial state, under this preparation method, assuming that the exponential distribution initial state is prepared for n quantum bits, the number of quantum gates required is approximately The basic gate complexity is O(n2 n) or O(Nlog2 N), and quantum entanglement is required between the qubits. It can be seen that in the related art, the preparation of exponentially distributed quantum states is achieved through arbitrary quantum initial state preparation methods. When the precision of the exponentially distributed quantum states to be prepared is high, that is, when the number of qubits n is large, the depth of the quantum circuit is deep, and the circuit execution time is long. As a result, during the operation of the quantum circuit, the entangled state between the qubits that were first quantum entangled will be disturbed and destroyed due to quantum decoherence effects. This makes it difficult for the quantum circuit to maintain high stability and reliability when the operation time is long, thereby affecting the stability and reliability of the prepared exponentially distributed quantum states to a certain extent.

[0017] Therefore, it is necessary to provide a method for preparing an exponentially distributed quantum state. The method can obtain a first preset parameter for representing the distribution law of the exponential distribution and a second preset parameter for representing the preparation accuracy, and then determine the number m of quantum bits used to prepare the exponentially distributed quantum state based on the first preset parameter and the second preset parameter. Then, a RY gate operation with a specified parameter is performed on each of the m quantum bits in the initial state to obtain a target quantum state representing the exponential distribution. The specified parameter is determined according to the first preset parameter and the second preset parameter, and the specified parameters corresponding to the RY gate operation performed on different quantum bits are different. The method for preparing an exponentially distributed quantum state provided in the embodiments of this specification can obtain a target quantum state representing the exponential distribution by applying only one RY gate on each quantum bit used for quantum state preparation. Its basic gate complexity is only O(n) or O(log2 N), and the depth of the quantum circuit can be fixed at one layer, which can effectively prevent the decoherence of the quantum bit to a certain extent and improve the stability and reliability of the prepared exponentially distributed quantum state. Moreover, compared with the general algorithm, the effective preparation of the exponentially distributed quantum state is achieved through a smaller number of quantum gates, which can also save computing resources to a certain extent and improve the efficiency of the preparation process. At the same time, the exponentially distributed quantum state preparation method provided in the embodiment of this specification utilizes the memoryless characteristics of the exponential distribution, so that there is no need to entangle the quantum bits during the initial state preparation of the quantum bits, so that the properties of the quantum bits can be retained to a large extent during the exponential distribution preparation process or in other quantum computing processes, further making the prepared exponentially distributed quantum state have higher stability and reliability.

[0018] See also Figure 1. One embodiment of the present specification provides a method for preparing an exponentially distributed quantum state. The exponentially distributed quantum state preparation method can be applied to a quantum computing unit, which can be a device that uses the characteristics of quantum mechanics to implement quantum computing. Specifically, the quantum computing unit can use the quantum state of the quantum bit as a data carrier, and drive the evolution of the quantum bit based on the linear superposition principle of the quantum state to implement a specified operation process. For example, the quantum computing unit can be a superconducting quantum bit control circuit implemented based on ultra-low temperature technology. Alternatively, the quantum computing unit can be a quantum bit control circuit built using quantum well technology. Of course, the quantum computing unit can also be an optical quantum integrated chip, etc.

[0019] In some embodiments, a quantum computing unit can function as a server. The quantum computing unit can provide computing services to connected clients. Clients can communicate with the quantum computing unit and send quantum computing tasks to the unit for processing. The quantum computing unit can then execute these tasks and return the results to the client.

[0020] In some embodiments, the quantum computing unit can communicate with a basic computing unit. The basic computing unit can be an electronic device with certain computing and display capabilities. Specifically, for example, the basic computing unit can include a desktop computer equipped with a display, a tablet computer, a laptop computer, a smartphone, a smart TV, or a smart wearable device.

[0021] The method for preparing an exponential distribution quantum state may include the following steps.

[0022] Step S110: Acquire a first preset parameter and a second preset parameter; wherein the first preset parameter is used to represent the distribution law of the exponential distribution; and the second preset parameter is used to represent the accuracy of the preparation of the exponential distribution quantum state.

[0023] In some cases, exponential distribution is a commonly used probability distribution, and the distribution law can usually be reflected by the parameters of the exponential distribution. Different parameters will result in different characteristics and properties of the exponential distribution. For example, the shape and distribution characteristics of the exponential distribution will be affected by the rate parameter λ of the exponential distribution. Therefore, by obtaining a first preset parameter that can affect the law or characteristics of the exponential distribution, an exponential distribution under the influence of different parameters can be prepared. In addition, the exponential distribution is a continuous probability distribution, and the preparation process of the exponential distribution quantum state usually uses a quantum state to approximate this continuous distribution. In this case, the prepared exponential distribution quantum state will have a certain degree of error compared to the continuous exponential distribution. The smaller the error, the higher the preparation accuracy, and vice versa. Therefore, by obtaining a second preset parameter that reflects the preparation accuracy, the exponential distribution quantum state can be prepared according to the accuracy requirements, increasing the preparation flexibility.

[0024] In this embodiment, the first preset parameter can be used to represent the distribution law of the exponential distribution to be prepared. The distribution law may include the shape, distribution characteristics, expectation, variance, etc. of the exponential distribution to be prepared. The first preset parameter can reflect these characteristics of the exponential distribution to be prepared. Specifically, for example, the first preset parameter may include the rate parameter λ of the exponential distribution, which can affect the family characteristics and shape of the exponential distribution. The first preset parameter may also include other parameters, such as the number of occurrences of a certain event obtained by statistics and the time interval between occurrences.

[0025] In this embodiment, the second preset parameter can be used to represent the preparation accuracy of the exponential distribution quantum state. The preparation accuracy can reflect the degree of approximation between the prepared exponential distribution and the continuous exponential distribution. The higher the accuracy, the higher the degree of approximation, and vice versa. Specifically, for example, the second preset parameter may include an error parameter, which can represent the difference between the probability value corresponding to each prepared quantum state and the probability value corresponding to the continuous exponential distribution. The difference can also be processed to obtain data having a certain mapping relationship with the difference, as an error parameter. Of course, the second preset parameter may also include other data that can reflect the degree of approximation.

[0026] In this embodiment, obtaining the first and second preset parameters can be used to determine the number of quantum bits required to prepare an exponentially distributed quantum state and the parameters of the required quantum logic gates. The first and second preset parameters can be obtained by directly obtaining the first and second preset parameters preset in the quantum computing unit, or by receiving the first and second preset parameters sent by a classical computer as a basic computing unit to a quantum computing unit. Of course, the quantum computing unit can also be used as a server to receive the first and second preset parameters sent by a client connected to it.

[0027] Step S120: Determine the number m of quantum bits used to prepare the exponentially distributed quantum state based on the first preset parameter and the second preset parameter.

[0028] In this embodiment, based on the obtained first and second preset parameters, by determining the number of qubits m required to prepare the exponentially distributed quantum state, the number of quantum gates and corresponding gate parameters used to prepare the exponentially distributed quantum state can be determined, so that corresponding quantum gate operations can be further performed on each qubit to obtain a target quantum state that obeys an exponential distribution. To determine the number of qubits m used to prepare the exponentially distributed quantum state, the number of qubits m required to prepare the exponentially distributed quantum state can be calculated based on the first and second preset parameters.

[0029] Step S130: Perform a RY gate operation with specified parameters on each of the m quantum bits in the initial state to obtain a target quantum state representing an exponential distribution; wherein the specified parameters are determined based on the first preset parameters and the second preset parameters; and the specified parameters corresponding to the RY gate operations performed on different quantum bits are different.

[0030] In some cases, using a general algorithm to prepare an exponential distribution of m qubits typically requires O(m2 m )-level quantum gates. In this embodiment, an RY gate operation with specified parameters is performed on each qubit in its initial state to obtain a target quantum state representing an exponential distribution. Thus, for m qubits, preparing an exponentially distributed quantum state requires m basic quantum gates. Quantum circuits do not require quantum entanglement, and the circuit depth is fixed at one layer. This reduces the number of gates required for exponentially distributed quantum state preparation and the depth of the quantum circuit. This not only improves preparation efficiency but also effectively prevents quantum decoherence, enhances the stability of quantum circuit operation, and ultimately improves the stability and reliability of the prepared exponentially distributed quantum state.

[0031] In this embodiment, the RY gate is used to operate the state of a quantum bit on a quantum computer. The RY gate can operate on the quantum bit using an angle parameter θ.

[0032] In this embodiment, the specified parameters of the RY gate can be used to control the RY gate to excite the quantum bit to a specific state. Furthermore, the specific state of the quantum bit can be used to form a target quantum state representing an exponential distribution. The specified parameters can be calculated and determined based on the first preset parameters and the second preset parameters. Since each quantum bit needs to be in a different specific state after the RY gate operation to represent the exponential distribution, the specified parameters corresponding to the RY gate operation on different quantum bits are different. In this way, for m quantum bits, after performing the corresponding RY gate operation on each quantum bit, each quantum bit can be excited to a corresponding specific state, and the superposition state formed by these m quantum bits can represent an exponential distribution that meets the first preset parameters and the second preset parameters. Specifically, for example, for three qubits in an initial state, the corresponding RY gate parameters θ can be 1.275, 1.004, and 0.5851, respectively. After RY gate operations with these parameters, these three qubits can form a superposition of eight states: |000>, |001>, |010>, |011>, |100>, |101>, |110>, and |111>. Each state and the probability value stored in it can be used to represent an exponential distribution with λ = 0.6. By executing three RY gates in parallel on each of the three qubits, an exponentially distributed quantum state with the corresponding accuracy can be prepared. The quantum circuit depth is fixed at one layer, reducing the quantum circuit runtime. Quantum entanglement is not required between the three qubits, preserving the qubit properties to a large extent. This improves the stability of the quantum circuit operation and further enhances the stability and reliability of the resulting exponentially distributed quantum state with λ = 0.6.

[0033] In this embodiment, the target quantum state may include a quantum superposition state formed after the quantum bits are respectively operated by the RY gate with specified parameters, and the multiple states included in the superposition state and their corresponding probability values are used to approximately represent a continuous exponential distribution. It can be understood that the more quantum bits there are, the higher the degree of approximation of the exponential distribution represented by the quantum superposition state formed after the RY gate operation with specified parameters, and the smaller the error. Therefore, when it is necessary to prepare a higher-precision exponential distribution quantum state, compared to the general algorithm, this embodiment does not require quantum entanglement of the quantum bits, and the depth of the quantum circuit is a fixed layer composed of a RY gate acting on each quantum bit, so that the operation of the prepared circuit has higher stability, and the prepared exponential distribution quantum state can also have higher stability and reliability. Specifically, for example, m quantum bits can represent 2 after being operated by the RY gate with specified parameters. mThe method uses a gate with a specified parameter RY to operate on each qubit, thereby maintaining the depth of the quantum circuit at a fixed level without requiring entanglement. This method effectively prevents quantum decoherence while preserving the characteristics of the qubits. This improves the stability and reliability of the prepared exponentially distributed quantum state even when high precision is required.

[0034] In some embodiments, the first preset parameter includes the rate parameter λ of the exponential distribution; the second preset parameter includes the error parameter ε; wherein the error parameter ε is used to represent the error between the exponential distribution obtained by the exponential distribution quantum state preparation method and the theoretical value of the continuous exponential distribution, and the continuous exponential distribution has the rate parameter λ.

[0035] In some cases, the rate parameter λ of an exponential distribution determines the distribution's family characteristics and shape, fully reflecting the distribution's regularity. Using this rate parameter as the first preset parameter for preparing an exponentially distributed quantum state, along with the error parameter ε as the second preset parameter, determines the number of qubits required to prepare the exponentially distributed quantum state and the parameters of each RY gate. This allows the exponential distribution represented by the prepared quantum state to closely approximate a continuous exponential distribution with the same rate parameter λ.

[0036] Please refer to Formula 1. In some embodiments, the step of determining the number m of qubits used to prepare the exponentially distributed quantum state based on the first preset parameter and the second preset parameter may include: determining the number m of qubits used to prepare the exponentially distributed quantum state based on the rate parameter λ and the error parameter ε of the exponential distribution; wherein the relationship between the number m of qubits and λ and ε is as follows:

[0037]

[0038] In some cases, after obtaining the exponential distribution rate parameter λ as the first preset parameter and the error parameter ε as the second preset parameter, the number of quantum bits m used to prepare the exponential distribution quantum state can be calculated and determined by the relationship between λ, ε and the number of quantum bits m used in the preparation process as shown in Formula 1, so as to further perform RY gate operations on the m quantum bits.

[0039] In some embodiments, the specified parameters include an angle parameter θ of the RY gate; wherein the angle parameter θ of each RY gate is different, and each of the angle parameters θ corresponds one-to-one to each of the quantum bits.

[0040] In some cases, for each of the m quantum bits, there is a specified angle parameter θ for performing the RY gate operation, and each specified angle parameter θ corresponds to a quantum bit, so that by operating the quantum bits through m RY gates, the exponential distribution quantum state preparation for the m quantum bits can be achieved.

[0041] See also Figure 2 、 Figure 3 , and Formula 2-Formula 8. In some embodiments, the step of performing a RY gate operation with a specified parameter on each of the m qubits in the initial state to obtain a target quantum state representing an exponential distribution may include: determining each of the angle parameters θ based on the rate parameter λ of the exponential distribution and the number of qubits m; wherein the angle parameter θ of the RY gate for any j-th qubit is j , the angle parameter can be calculated and determined by the following formula:

[0042]

[0043] For each qubit in the initial state, a corresponding RY gate operation is performed, so that the qubit is in a target state representing an exponential distribution after the RY gate operation; wherein the RY gate corresponding to any j-th qubit has the angle parameter θ j .

[0044] In some cases, after determining the number m of qubits used to prepare an exponentially distributed quantum state, it is necessary to apply an RY gate to each of the m qubits so that the m qubits are excited to a state that can be used to represent the exponential distribution through the RY gate. In this case, the parameter setting of the RY gate is required to satisfy a certain relationship with the probability distribution function of the prepared exponential distribution, that is, the relationship shown in Formula 2. Specifically, the angle parameter θ shown in Formula 2 is j The relationship that needs to be satisfied can be obtained by the following process:

[0045] First, according to the memorylessness of the exponential distribution, we can have the following formula:

[0046]

[0047] Then the distribution function f(t)=P[τ l ≤t] can satisfy:

[0048]

[0049] For formula 4, we can take the derivative of s and let s = 0 to obtain the following formula:

[0050]

[0051] Furthermore, since -f′(0) is a constant, we can solve the differential equation to obtain the following formula:

[0052]

[0053] For Formula 6, since Therefore, the interval time of a certain memoryless time follows an exponential distribution. When T is large enough, it can be truncated, that is, the situation when it exceeds T is not considered. To meet the normalization requirements, it can be processed according to the following formula:

[0054]

[0055] Next, starting from the |0> state of m=log T qubits, the RY(θ j ) gate, the tensor can be directly calculated through the following process:

[0056]

[0057] In the above formula 8, |k1k2..k m > represents any state in the superposition state formed by the m qubits. Specifically, for example, for 3 qubits, |k1k2..k m > can represent any state among |000>, |001>, |010>, |011>, |100>, |101>, |110>, |111>. |t> represents the corresponding state obtained after binary encoding. Specifically, for example, for 3 quantum bits, t can be equal to 0, 1, 2...7, and for m quantum bits, t can be equal to 0, 1, 2...2 m -1, that is, 0~(T-1).

[0058] According to the process of Formula 3 to Formula 8 above, it can be understood that in this embodiment, for the m qubits, they can be excited to the target state after performing the RY gate operation that satisfies the specified angle parameter in Formula 2, and the probability value stored in the superposition state formed by the m qubits in the target state corresponds to the probability value of the exponential distribution function in Formula 7. Therefore, the obtained quantum state can represent the corresponding exponential distribution. Specifically, for example, Figure 2 and Figure 3The quantum circuit prepared to satisfy the exponential distribution quantum state with λ=0.6 and ε=0.01 and the probability distribution obtained by measuring the basic basis. Figure 2 The three duration quantum bits τ0-τ2 in the quartz crystal are respectively subjected to RY gate operations with angle parameters of 1.275, 1.004, and 0.0581, and the state records of multiple measurements are obtained. Figure 3 Probability distribution diagram in .

[0059] In some embodiments, the exponentially distributed quantum state is used to simulate the probability distribution of asset price fluctuations; wherein, the target quantum state includes multiple states representing multiple asset price fluctuations; the determined state of the m quantum bits in the target quantum state obtained after measurement represents one of the simulated asset price fluctuations.

[0060] In some cases, since the exponential distribution has the characteristic of being memoryless, this characteristic is consistent with the characteristics of asset price fluctuations, that is, future price changes are not affected by past price changes. Therefore, the exponential distribution quantum state prepared in this embodiment can be used as a probability density model of price changes to simulate the probability distribution of asset price fluctuations.

[0061] In this embodiment, for the m qubits, the target quantum state obtained by the exponential distribution quantum state preparation process may include 2 m states and their corresponding probabilities, and further, can represent multiple possible values of price fluctuations and their corresponding probabilities. The determined state obtained by performing a single measurement on the m qubits in the target quantum state can represent the value of the random fluctuation of the asset price that obeys the exponential probability distribution under this measurement. Specifically, for example, for an exponentially distributed quantum state prepared by 3 qubits, the determined state obtained by a single measurement is |010>, then the asset price fluctuation represented by the state |010> can be used as the result data of this measurement. It can be understood that by performing multiple measurements on the m qubits in the target quantum state, the result data representing the asset price fluctuation under multiple measurements can be obtained as the result of multiple random values of the random change of the asset price that obeys the exponential distribution.

[0062] In some embodiments, the exponentially distributed quantum state includes multiple, and the multiple exponentially distributed quantum states are used to simulate the asset price fluctuation trend; wherein, the m quantum bits used to prepare each of the exponentially distributed quantum states constitute a quantum bit group; the multiple determined states obtained after measurement of the multiple quantum bit groups in the exponentially distributed quantum states represent the simulated multiple asset price fluctuations; the multiple asset price fluctuations are used to simulate the asset price fluctuation trend.

[0063] In some cases, the prepared exponentially distributed quantum states may include multiple ones, for use in simulating the probability distribution of multiple asset price changes. Thus, by performing a single measurement on multiple qubits in the exponentially distributed quantum states, a set of result data representing the price fluctuation process can be obtained, as the result of a single random process simulation of the random changes in asset prices that obey the exponential distribution, for use in representing a fluctuation trend in asset prices. It will be understood that by performing multiple measurements on the multiple qubits in the exponentially distributed quantum states, a set of result data representing multiple price fluctuation processes can be obtained, as the result of multiple random process simulations of the random changes in asset prices that obey the exponential distribution, for use in representing multiple fluctuation trends in asset prices.

[0064] In this embodiment, a qubit group may include m qubits used to prepare an exponentially distributed quantum state. Thus, the superposition state formed by the qubits in a qubit group can represent multiple possible values of price fluctuations and their corresponding probabilities. After measurement, the qubit group can produce result data representing the simulated asset price. It can be understood that the multiple determined states obtained after a single measurement of multiple qubit groups can serve as a set of result data representing multiple simulated asset price fluctuations. This set of result data can be used to simulate a single process of asset price fluctuations, that is, a trend of asset price fluctuations. Furthermore, multiple measurements can simulate multiple fluctuation trends of asset prices.

[0065] See also Figure 4 One embodiment of this specification provides a device for preparing an exponentially distributed quantum state. The device may include:

[0066] An acquisition module; used to acquire a first preset parameter and a second preset parameter; wherein the first preset parameter is used to represent the distribution law of the exponential distribution; and the second preset parameter is used to represent the accuracy of the preparation of the exponential distribution quantum state;

[0067] A determination module; configured to determine the number m of quantum bits used to prepare the exponentially distributed quantum state based on the first preset parameter and the second preset parameter;

[0068] An execution module; used to perform an RY gate operation with specified parameters on m quantum bits in an initial state, respectively, to obtain a target quantum state used to represent an exponential distribution; wherein the specified parameters are determined based on the first preset parameters and the second preset parameters; and the specified parameters corresponding to the RY gate operations performed on different quantum bits are different.

[0069] Regarding the specific functions and effects achieved by the exponential distribution quantum state preparation device, please refer to the other embodiments of this specification for comparison and explanation, and will not be repeated here. The various modules in the exponential distribution quantum state preparation device can be implemented in whole or in part by software, hardware, and a combination thereof. The modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

[0070] See also Figure 5 . The embodiment of this specification also provides a computer device, including a memory and a processor, the memory storing a computer program, characterized in that when the processor executes the computer program, it implements the method for preparing an exponentially distributed quantum state in any of the above embodiments. The computer device can be a classical computer. The computer device can also be a quantum computer. The computer device can include a processor, a non-volatile storage medium, an internal memory, a communication interface, a display device, and an input device connected by a system bus. The non-volatile storage medium can store an operating system and related computer program instructions.

[0071] The embodiments of this specification also provide a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a computer, the computer executes the method for preparing an exponentially distributed quantum state in any of the above embodiments.

[0072] It should be understood that the specific examples herein are only intended to help those skilled in the art better understand the embodiments of this specification, rather than to limit the scope of the present invention.

[0073] It can be understood that in the various implementations of this specification, the size of the serial number of each process does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the implementation methods of this specification.

[0074] It can be understood that the various embodiments described in this specification can be implemented individually or in combination, and the embodiments in this specification are not limited to this.

[0075] Unless otherwise indicated, all technical and scientific terms used in the embodiments of this specification have the same meaning as those commonly understood by those skilled in the art in the technical field of this specification. The terms used in this specification are only for the purpose of describing specific embodiments and are not intended to limit the scope of this specification. The term "and / or" used in this specification includes any and all combinations of one or more related listed items. The singular forms "a", "above", and "the" used in the embodiments of this specification and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.

[0076] It is understood that the processor in the embodiments of this specification can be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method embodiment can be completed by hardware integrated logic circuits in the processor or software instructions. The above processor can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. The various methods, steps, and logic block diagrams disclosed in the embodiments of this specification can be implemented or executed. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in the embodiments of this specification can be directly implemented as being executed by a hardware decoding processor, or by a combination of hardware and software modules in the decoding processor. The software module can be located in a storage medium mature in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, etc. The storage medium is located in the memory, and the processor reads the information in the memory and completes the steps of the above method in combination with its hardware.

[0077] It will be understood that the memory in the embodiments of this specification may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM). It should be noted that the memory of the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0078] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this specification.

[0079] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described systems, devices and units can refer to the corresponding processes in the aforementioned method implementation methods and will not be repeated here.

[0080] In the several embodiments provided in this specification, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0081] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of this embodiment.

[0082] In addition, each functional unit in each embodiment of this specification may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0083] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this specification, or the part that contributes to the prior art, or the part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of this specification. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0084] The above description is merely a specific embodiment of this specification, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this specification should be included within the scope of protection of this specification. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for preparing an exponentially distributed quantum state, characterized in that: The method comprises: Get the rate parameter of the exponential distribution and error parameters ; Wherein, the error parameter Used to represent the error between the exponential distribution obtained by the exponential distribution quantum state preparation method and the theoretical value of the continuous exponential distribution, wherein the continuous exponential distribution has the rate parameter ; According to the rate parameter of the exponential distribution and the error parameter , determine the number of quantum bits used to prepare the exponentially distributed quantum state ; Wherein, the number of quantum bits ; For the initial state qubits, each executing a specified parameter Gate operation to obtain a target quantum state for representing an exponential distribution; wherein the specified parameter is determined according to a first preset parameter and a second preset parameter; the first preset parameter includes the rate parameter ; The second preset parameter includes the error parameter ; Different qubits are executed The specified parameters for the gate operations are different.

2. The method according to claim 1, characterized in that The specified parameters include the Door angle parameters ; Each Door angle parameters Different, each of the angle parameters There is a one-to-one correspondence with each of the quantum bits.

3. The method according to claim 2, characterized in that For the initial state qubits, each executing a specified parameter The gate operation to obtain the target quantum state for representing the exponential distribution includes the following steps: According to the rate parameter of the exponential distribution and the number of qubits , determine each of the angle parameters ; Among them, for any qubits Door angle parameters , the angle parameter , , ; For each quantum bit in the initial state, execute the corresponding Gate operation, so that the quantum bit After the gate operation, the target state represents the exponential distribution; qubits The door has the angle parameters .

4. A device for preparing an exponentially distributed quantum state, characterized in that: The device comprises: Acquisition module; used to obtain the rate parameter of the exponential distribution and error parameters ; Wherein, the error parameter Used to represent the error between the exponential distribution obtained by the exponential distribution quantum state preparation method and the theoretical value of the continuous exponential distribution, wherein the continuous exponential distribution has the rate parameter ; Determine module; for the rate parameter according to the exponential distribution and the error parameter , determine the number of quantum bits used to prepare the exponentially distributed quantum state ; Wherein, the number of quantum bits ; Execution module; used to execute the qubits, each executing a specified parameter Gate operation to obtain a target quantum state for representing an exponential distribution; wherein the specified parameter is determined according to a first preset parameter and a second preset parameter; the first preset parameter includes the rate parameter ; The second preset parameter includes the error parameter ; Different qubits are executed The specified parameters for the gate operations are different.

5. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the method according to any one of claims 1 to 3 is implemented.

6. A computer-readable storage medium, characterized in that The readable storage medium stores computer program instructions, and when the program is executed by a processor, the method according to any one of claims 1 to 3 is implemented.

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