CN114202073B

CN114202073B - Pulse sequence generation method, control method, device, system and equipment

Info

Publication number: CN114202073B
Application number: CN202111505171.6A
Authority: CN
Inventors: 汪景波; 段宇丞
Original assignee: Beijing Baidu Netcom Science and Technology Co Ltd
Current assignee: Beijing Baidu Netcom Science and Technology Co Ltd
Priority date: 2021-12-10
Filing date: 2021-12-10
Publication date: 2024-07-23
Anticipated expiration: 2041-12-10
Also published as: CN114202073A

Abstract

The disclosure provides a pulse sequence generation method, a control method, a device, a system and equipment based on an ion trap, and relates to the field of data processing, in particular to the field of quantum computing. The specific implementation scheme is as follows: determining the number N of slices required by slicing the amplitude and the phase of the current laser signal, and performing slicing to obtain a first symmetrical pulse sequence formed by N amplitude slices and N phase slices; wherein the N amplitude slices satisfy a first symmetry, and the N phase slices satisfy a second symmetry; simulating the first symmetrical pulse sequence to be applied to preset ion qubits of an ion trap so as to obtain a first approximate qubit gate; and under the condition that at least the degree of difference between the first approximate qubit gate and the target qubit gate meets a preset condition, taking the current first symmetrical pulse sequence as a target pulse sequence. Thus, the anti-interference capability of the scheme is improved.

Description

Pulse sequence generation method, control method, device, system and equipment

Technical Field

The present disclosure relates to the field of data processing technology, and in particular to the field of quantum computing.

Background

In recent years, ion trap quantum computing platforms have rapidly evolved, and the performance of ion trap chips has also shown explosive growth. An indicator of the performance of a quantum chip, such as a quantum volume on an ion trap chip, increases rapidly from 512 quantum volumes to 400 tens of thousands of quantum volumes. Ion trap quantum computing platforms have demonstrated superior results in small-scale molecular modeling and demonstration of quantum properties. It can be said that, at present, the ion trap quantum computing platform has been stepped into the middle noise scale quantum computing era, and more quantum computing applications will be demonstrated and verified on ion trap quantum computing hardware in the future.

Disclosure of Invention

The disclosure provides a pulse sequence generation method, a control method, a device, a system and equipment based on an ion trap.

According to an aspect of the present disclosure, there is provided a pulse sequence generation method based on an ion trap, including:

Determining the number N of slices required by slicing the amplitude and the phase of the current laser signal, and performing slicing to obtain a first symmetrical pulse sequence formed by N amplitude slices and N phase slices; wherein the N amplitude slices satisfy a first symmetry, and the N phase slices satisfy a second symmetry; n is an integer greater than or equal to 2;

simulating the first symmetrical pulse sequence to be applied to preset ion qubits of an ion trap so as to obtain a first approximate qubit gate;

And under the condition that at least the degree of difference between the first approximate qubit gate and the target qubit gate meets a preset condition, taking the current first symmetrical pulse sequence as a target pulse sequence.

According to another aspect of the present disclosure, there is provided a pulse sequence control method based on an ion trap, including:

Applying a target pulse sequence to a preset ion qubit of an ion trap; the target pulse sequence is the pulse sequence obtained by the method;

And measuring to obtain a target approximate qubit gate, wherein the degree of difference between the target approximate qubit gate and the target qubit gate meets a preset condition.

According to still another aspect of the present disclosure, there is provided an ion trap-based pulse train generating apparatus, comprising:

The pulse sequence generating unit is used for determining the number N of slices required by slicing the amplitude and the phase of the current laser signal, and performing slicing processing to obtain a first symmetrical pulse sequence formed by N amplitude slices and N phase slices; wherein the N amplitude slices satisfy a first symmetry, and the N phase slices satisfy a second symmetry; n is an integer greater than or equal to 2;

the simulation calculation unit is used for simulating the first symmetrical pulse sequence to be applied to preset ion qubits of the ion trap so as to obtain a first approximate qubit gate;

and the result output unit is used for taking the current first symmetrical pulse sequence as a target pulse sequence under the condition that at least the difference degree between the first approximate quantum bit gate and the target quantum bit gate meets a preset condition.

According to yet another aspect of the present disclosure, there is provided an ion trap-based pulse sequence control system comprising:

An ion trap;

A laser transmitter for applying a target pulse sequence to a predetermined ion qubit of the ion trap; the target pulse sequence is obtained by the pulse sequence generation method;

and the measuring equipment is used for measuring and obtaining a target approximate qubit gate, wherein the degree of difference between the target approximate qubit gate and the target qubit gate meets a preset condition.

According to still another aspect of the present disclosure, there is provided an electronic apparatus including:

at least one processor; and

A memory communicatively coupled to the at least one processor; wherein,

The memory stores instructions executable by the at least one processor to enable the at least one processor to perform the pulse sequence generation method described above.

According to yet another aspect of the present disclosure, there is provided a non-transitory computer-readable storage medium storing computer instructions for causing the computer to perform the pulse sequence generation method described above.

According to a further aspect of the present disclosure, there is provided a computer program product comprising a computer program which, when executed by a processor, implements the pulse sequence generation method described above.

In this way, the scheme of the present disclosure provides a pulse sequence generation scheme for an ion trap, in which the amplitude slice and the phase slice are symmetrically designed, so as to improve the anti-interference capability of the scheme of the present disclosure.

It should be understood that the description in this section is not intended to identify key or critical features of the embodiments of the disclosure, nor is it intended to be used to limit the scope of the disclosure. Other features of the present disclosure will become apparent from the following specification.

Drawings

The drawings are for a better understanding of the present solution and are not to be construed as limiting the present disclosure. Wherein:

Fig. 1 is a schematic flow diagram of an implementation of a pulse train generation method based on an ion trap in accordance with an embodiment of the present disclosure;

fig. 2 is a schematic flow diagram of an implementation of an ion trap based pulse sequence control method in accordance with an embodiment of the present disclosure;

fig. 3 is a schematic diagram of a pulse train control system based on an ion trap in accordance with an embodiment of the present disclosure;

fig. 4 (a) is a schematic flow diagram of an implementation of an ion trap-based pulse train generation method in a specific example according to an embodiment of the present disclosure;

FIG. 4 (b) is a data comparison schematic of a resulting qubit gate according to an embodiment of the present disclosure with a prior art scheme;

Fig. 5 is a schematic structural diagram of an ion trap-based pulse train generating apparatus according to an embodiment of the present disclosure;

fig. 6 is a block diagram of an electronic device for implementing an ion trap based pulse train generation method in accordance with an embodiment of the present disclosure.

Detailed Description

Exemplary embodiments of the present disclosure are described below in conjunction with the accompanying drawings, which include various details of the embodiments of the present disclosure to facilitate understanding, and should be considered as merely exemplary. Accordingly, one 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 disclosure. Also, descriptions of well-known functions and constructions are omitted in the following description for clarity and conciseness.

In ion trap quantum computation, a space potential field capable of confining charged ions is formed by injecting an alternating electric field into electrodes around an ion trap. In addition, a two-dimensional modularized ion trap binding technology has been developed, in which a modularized surface binding space is formed on the surface of an ion trap chip by laying a microelectrode on the base of the ion trap chip by micro-nano processing, and ion qubits (ions are quantum bits, which may be called ion qubits) are modularly distributed on a two-dimensional plane space. And completing a preliminary expansion scheme of the ion quantum bit by moving the ion quantum bit through an electric field. The ion can be used as a qubit because the same ion in nature has the same internal energy level at low temperature and shows the same characteristic, so the ion is a natural qubit calculation carrier. With a qubit carrier, if a specific task of quantum computation is to be completed on the carrier (i.e., ions), a proper operation is also required for the qubit carrier. For example, taking a common ytterbium (yb+) ion as an example, in the absence of an external magnetic field, an intra-ion state |f=0, m _F =0 > may be selected as the |0> state of the qubit, and an intra-ion state |f=0, m _F =0 > may be selected as the |1> state of the qubit. The qubit is formed in these two states, and the states of the qubit sequence composed of yb+ ions bound in the potential well are identical. The inversion of each ion qubit between the states of |0> and |1> can be conveniently achieved by two beams of opposite Raman light, thereby achieving single qubit gate operation in an ion trap. For double or more qubit gate operation in an ion trap, it is often necessary to apply a broad beam of laser light (i.e., laser signal) to a long chain of ions (i.e., ion chain) in the ion trap, while simultaneously introducing several separate beams of laser light in opposite directions to act on the ion qubit(s) to be operated on (e.g., two or more). And through phonon modes formed by coulombs in the ion chain, quantum information transmission between two or more ion qubits is completed, and a primary multi-quantum bit gate in the ion trap is formed. However, with the increasing number of ion trap qubits and complex quantum tasks, high demands are placed on the accuracy of the operation of ion trap qubit gates (i.e., the resulting qubit gates based on ion traps, hereinafter referred to as ion trap qubit gates). Moreover, within an ion trap chip, both the long chains of ions (i.e., ion chains) in the vacuum chamber, and the phonon vibration frequencies used to transfer quantum information between ion qubits, change with the coupling of ions to the environment and the laser pumping action. In addition, due to the precision of the laboratory laser pulse generator, there may be Xu Xingbian between the actual pulse shape and the ideal pulse. Factors present in the real environment affect the accuracy of operation of the ion trap qubit gate.

In quantum computers, each computational task can be broken down into a combination of a series of quantum gates, commonly single and double quantum bit gates. And different quantum computing hardware platforms use different control means. For ion trap quantum computing platforms, a laser control manner is often adopted to implement a native quantum gate (i.e., a native ion trap quantum bit gate, hereinafter referred to as a native quantum gate) in ion trap quantum computing. For purposes of the present disclosure, native quantum gates refer to quantum gates that are easier to implement quantum operations on this hardware platform (e.g., ion trap quantum computers for the purposes of the present disclosure). For example, for an ion trap, a native quantum gate may include an Rx quantum gate rotated about the X-axis and an Ry quantum gate rotated about the Y-axis that operate on a single ion qubit, as well as linking multiple ion qubitsAnd (3) a door. The accuracy of these native quantum gates is strongly dependent on the manner in which the laser pulses are generated, as well as on the working operating environment of the ions in the ion trap.

Therefore, it is a very necessary and interesting task to design ion trap control pulses that are resistant to ambient noise interference. Moreover, how to effectively cope with an increasing number of ion qubits and how to realize high-precision quantum gates on ion trap chips containing various environmental noises so as to complete quantum tasks are indispensable technologies for ion trap quantum computation.

Based on the above, the present disclosure provides a control pulse generation scheme for an ion trap, specifically, the present disclosure adopts the idea of symmetric pulse design, by designing the amplitude into a symmetric slice, designing the phase into an antisymmetric scheme, and by a suitable optimization algorithm, a pulse sequence required for generating an ion trap quantum bit gate is obtained, and the distortion degree is very low. Under most ion traps, the number of slices of the disclosed scheme grows linearly with the number of ion qubits. Moreover, the control pulse generation scheme disclosed by the scheme has strong anti-interference capability on noise factors such as laser detuning offset, phonon frequency drift, pulse deformation and the like.

Specifically, the disclosed scheme provides a pulse sequence generating method based on an ion trap, specifically, as shown in fig. 1, including:

Step S101: determining the number N of slices required by slicing the amplitude and the phase of the current laser signal, and performing slicing to obtain a first symmetrical pulse sequence formed by N amplitude slices and N phase slices; wherein the N amplitude slices satisfy a first symmetry, and the N phase slices satisfy a second symmetry; n is an integer greater than or equal to 2.

Step S102: and simulating the first symmetrical pulse sequence to be applied to preset ion qubits of the ion trap so as to obtain a first approximate qubit gate. It should be noted that the number of preset ion qubits may be one or two or more, and is related to the target qubit gate to be implemented; for example, when the target qubit gate to be implemented is a double qubit gate, the number of preset ion qubits is 2, in other words, the target qubit gate is implemented by performing a quantum operation on the preset ion qubits in the ion trap.

Step S103: and under the condition that at least the degree of difference between the first approximate qubit gate and the target qubit gate meets a preset condition, taking the current first symmetrical pulse sequence as a target pulse sequence. At this time, the qubit gate obtained based on the target pulse sequence is a target approximate qubit gate, wherein the degree of difference between the target approximate qubit gate and the target qubit gate satisfies a preset condition.

In this way, the present disclosure provides a pulse sequence generation scheme for an ion trap, in which an amplitude slice and a phase slice are symmetrically designed, so as to maximize resistance to interference caused by noise in an actual environment process, so as to obtain a target pulse sequence capable of approximately realizing a target qubit gate.

Moreover, the scheme disclosed by the invention does not limit the specific structure of the ion trap, so that the applicability and the expandability are strong.

In a specific example of the present disclosure, in a case where the degree of difference between the first approximate qubit gate and the target qubit gate does not satisfy the preset condition, adjusting and optimizing the amplitude and the phase of the current laser signal, for example, adjusting specific values of the amplitude and the phase of the current laser signal to update the first symmetric pulse sequence; and then after the first symmetrical pulse sequence is updated, simulating the first symmetrical pulse sequence to be applied to preset ion qubits of the ion trap again so as to obtain a first approximate qubit gate again, and circulating the steps until at least the difference degree between the first approximate qubit gate and the target qubit gate meets preset conditions.

Therefore, the ion trap control pulse is obtained in a pulse optimization mode, the method is high in availability, optimization iteration can be performed based on different actual environment noise conditions, and the expandability is high.

In a specific example of the solution of the present disclosure, the number of slices N may also be obtained in the following manner, specifically including: acquiring parameter information of an ion trap required for realizing the target qubit gate; wherein, the determining the slicing number N required for slicing the amplitude and phase of the current laser signal includes: based on the parameter information, the number of slices N required for slicing the amplitude and phase of the current laser signal is determined. That is, the number of slices N in the solution of the present disclosure may refer to the parameter information of the ion trap actually used, so that the parameter condition of the actual experimental apparatus is fully considered, and the parameter condition of the actual experimental apparatus is also compatible, so that the applicability and the expandability of the solution of the present disclosure are both strong.

In a specific example of the disclosed aspects, the parameter information characterizes at least a number of ion qubits in the ion trap; at this time, the determining the number of slices N required for slicing the amplitude and phase of the current laser signal based on the parameter information described above may specifically include: based at least on the number of ion qubits in the ion trap, a number of slices N required to slice the amplitude and phase of the current laser signal is determined. That is, the number of slices N in the solution of the present disclosure is related to the number of ion qubits in the ion trap, so that the parameter conditions of the actual experimental equipment are fully considered, and the parameter conditions of the actual experimental equipment are compatible, so that the solution of the present disclosure has strong applicability and expandability.

In a specific example of the disclosed arrangement, the number of slices N is linearly positively correlated with the number of ion qubits in the ion trap. That is, the number of slices N described by the present disclosure is linearly positively correlated with the number of ion qubits in the ion trap; for example, for 5 ion qubits, the N may take a value of 10; for 10 ion qubits, the N may take on any number from 15 to 20. Thus, the disclosed solution is also applicable in large-scale ion trap chip structures. Moreover, since the number of slices N is in linear positive correlation with the number of ion qubits in the ion trap, the scheme disclosed by the invention can be further popularized to a pulse generation scheme of parallel multi-quantum bit gates in the ion trap, and the application range and the scalability are strong.

In a specific example of the solution of the present disclosure, the N amplitude slices satisfy a first symmetry relationship, specifically including: omega ₁＝Ω_N,…,Ω_i＝Ω_N-i+1; here, Ω characterizes an i-th amplitude slice, where i is an integer of 1 or more and N or less. Thus, the interference problem caused by noise in the actual environment process is maximally resisted, so that a target pulse sequence capable of approximately realizing a target quantum bit gate is obtained.

In a specific example of the solution of the present disclosure, the N phase slices satisfy the second symmetry relationship, specifically including: phi ₁＝-φ_N,…,φ_i＝-φ_N-i+1; here, the Φi characterizes an i-th phase slice, and the i is an integer of 1 or more and N or less. Thus, the interference problem caused by noise in the actual environment process is maximally resisted, so that a target pulse sequence capable of approximately realizing a target quantum bit gate is obtained.

In a specific example of the solution of the present disclosure, the first approximate qubit gate is obtained by, specifically, simulating that the first symmetric pulse sequence is applied to a preset ion qubit of an ion trap to obtain the first approximate qubit gate, which specifically includes: and simulating that the first symmetrical pulse sequence is applied to preset ion qubits of the ion trap, and obtaining a first approximate qubit gate under the condition that the surrounding of the ion trap is simulated to be free of environmental noise.

That is, the problem of environmental noise can be fully considered in the simulation process, for example, the first approximate quantum bit gate without environmental noise is obtained through simulation, so that a foundation is laid for maximizing the interference of resisting the environmental noise.

In a specific example of the present disclosure, the following manner may be adopted to fully consider the environmental noise, obtain the target difference degree, and further determine whether the target difference degree meets the preset condition. In particular, the method comprises the steps of,

Mode one: the method specifically comprises the following steps:

estimating an ambient noise range around the ion trap, wherein the ambient noise range characterizes that the ambient noise around the ion trap is larger than or equal to a first noise value and smaller than or equal to a second noise value, and the first noise value is smaller than the second noise value;

Simulating a preset ion qubit applied to an ion trap by the first symmetrical pulse sequence, and obtaining a second approximate qubit gate under the condition that the ion trap is simulated to be at the first noise value;

determining a degree of difference between the second approximate qubit gate and the target qubit gate;

Obtaining a target degree of difference based at least on the degree of difference between the second approximate qubit gate and the target qubit gate, and the degree of difference between the first approximate qubit gate and the target qubit gate; for example, the two are subjected to addition processing to obtain the total difference degree, namely the target difference degree.

At this time, the degree of difference between the at least first approximate qubit gate and the target qubit gate satisfies a preset condition, including:

the target difference degree meets a preset condition.

That is, in the simulation process, the environmental noise problem can be fully considered, for example, a first approximate qubit gate without environmental noise is obtained through simulation, a second approximate qubit gate with environmental noise obtained under the first noise value is obtained through simulation, and then the basis is laid for maximizing the interference of resisting the environmental noise based on the difference degree between the second approximate qubit gate and the target qubit gate, and the difference degree between the first approximate qubit gate and the target qubit gate, for example, based on the total difference degree obtained by the first approximate qubit gate and the target qubit gate, so that whether the preset condition is met or not is determined.

Mode two: the method specifically comprises the following steps:

simulating a preset ion qubit applied to an ion trap by the first symmetrical pulse sequence, and obtaining a third approximate qubit gate under the condition that the ion trap is simulated to be at the second noise value;

determining a degree of difference between the third approximate qubit gate and the target qubit gate;

Obtaining a target degree of difference based at least on the degree of difference between the third approximate qubit gate and the target qubit gate, and the degree of difference between the first approximate qubit gate and the target qubit gate; for example, the two are subjected to addition processing to obtain the total difference degree, namely the target difference degree.

At this time, the degree of difference between at least the first approximate qubit gate and the target qubit gate satisfies a preset condition, which specifically includes:

the target difference degree meets a preset condition.

That is, in the simulation process, the environmental noise problem can be fully considered, for example, a first approximate qubit gate without environmental noise is obtained through simulation, a third approximate qubit gate with environmental noise obtained under a second noise value is obtained through simulation, and then the basis is laid for maximizing the interference of resisting environmental noise based on the difference degree between the third approximate qubit gate and the target qubit gate, and the difference degree between the first approximate qubit gate and the target qubit gate, for example, based on the total difference degree obtained by the first approximate qubit gate and the target qubit gate, so that whether the preset condition is met or not is determined.

The third mode specifically includes:

Obtaining a target degree of difference based at least on the degree of difference between the first approximate qubit gate and the target qubit gate, the degree of difference between the second approximate qubit gate and the target qubit gate, and the degree of difference between the third approximate qubit gate and the target qubit gate; for example, the three are added to obtain the total difference degree, i.e. the target difference degree.

Wherein the degree of difference between the at least first approximate qubit gate and the target qubit gate satisfies a preset condition, comprising:

the target difference degree meets a preset condition.

That is, in the simulation process, the environmental noise problem, for example, a first approximate qubit gate without environmental noise is obtained through simulation, and a second approximate qubit gate with environmental noise obtained under the first noise value is obtained through simulation, a third approximate qubit gate with environmental noise obtained under the second noise value is obtained through simulation, and further, based on the difference degree between the third approximate qubit gate and the target qubit gate, the difference degree between the second approximate qubit gate and the target qubit gate, and the difference degree between the first approximate qubit gate and the target qubit gate, for example, based on the total difference degree obtained by the three, are also fully considered, so that whether preset conditions are met or not is determined, and a foundation is laid for maximizing the interference of resisting the environmental noise.

It should be noted that the above three modes may be alternatively executed, which is not limited by the present disclosure. Or in practical application, based on the thought of the second mode or the third mode, selecting any noise value from the environment noise range to obtain an approximate quantum bit gate under the any noise value, and further obtaining the difference degree between the approximate quantum bit gate and the target quantum bit gate; and then adding the new target difference degree with other noise values or difference degrees under the noiseless value to obtain the new target difference degree so as to judge whether the new target difference degree meets the preset condition.

In a specific example of the present disclosure, the verification may also be performed in such a manner that, in particular, the ambient noise range is adjusted to decrease the first noise value and to increase the second noise value; and under the condition that the range of the environmental noise is enlarged, the target difference degree (such as the target difference degree obtained by adopting any one of the first to third modes) is obtained again so as to verify whether the target difference degree meets the preset condition. Thus, the environment noise range which can be resisted by the target pulse sequence obtained through optimization is verified to determine the scene which can be applied by the scheme.

In a specific example of the disclosed aspects, the target qubit gate is a native quantum gate that can be realized by the ion trap. Therefore, the usability and the practicability of the scheme are higher.

In a specific example of the disclosed scheme, the target qubit gate is a two-qubit gate, or a multiple-qubit gate. Therefore, a pulse sequence generation scheme with strong anti-interference capability is provided for two quantum bit gates or multiple quantum bit gates, and the quantum bit gates are not limited by the scheme, so that the application range is wide, and the expandability is strong.

It should be noted that, the degree of difference described in the present disclosure may be measured specifically by fidelity and distortion, and the present disclosure does not limit specific measurement indexes.

Moreover, the scheme disclosed by the invention does not limit the specific structure of the ion trap, so that the application is strong, the expandability is also strong, and a feasible scheme is provided for realizing quantum computing tasks based on the ion trap.

The disclosed scheme also provides a pulse sequence control method based on the ion trap, specifically, as shown in fig. 2, comprising:

Step S201: applying a target pulse sequence to a preset ion qubit of an ion trap; the target pulse sequence is obtained by the pulse sequence generation method.

Step S202: and obtaining a target approximate qubit gate, wherein the degree of difference between the target approximate qubit gate and the target qubit gate meets a preset condition.

Thus, the present disclosure provides a pulse sequence control scheme for an ion trap resulting in a target pulse sequence that is capable of approximately achieving a target qubit gate. Because the pulse sequence is obtained by optimizing the symmetrical design of the amplitude slice and the phase slice, the interference problem caused by noise in the actual environment process can be maximally resisted. Moreover, the scheme disclosed by the invention does not limit the specific structure of the ion trap, so that the application is strong, the expandability is also strong, and a feasible scheme is provided for realizing quantum computing tasks based on the ion trap.

Further, the present disclosure further provides a pulse sequence control system based on an ion trap, for implementing the pulse sequence control method described above, specifically, as shown in fig. 3, the system includes:

an ion trap 301;

A laser transmitter 302, such as a laser pulse generator, for applying a target pulse train to a predetermined ion qubit of the ion trap; the target pulse sequence is the pulse sequence obtained by the pulse sequence generation method;

A measuring device 303, such as a photon detector, is used for measuring and obtaining a target approximate qubit gate, wherein the degree of difference between the target approximate qubit gate and the target qubit gate meets a preset condition.

The following describes aspects of the present disclosure in further detail, with reference to specific examples; specifically, the present disclosure proposes an anti-noise ion trap control pulse (i.e., target pulse train) generation scheme. Specifically, by means of the symmetrical pulse design concept and the pulse optimization method containing edge noise information, ion trap control pulses resistant to various environmental noises are realized. The ion trap control pulse generated by the scheme has the characteristic of strong anti-interference capability on various noises generated by the ion trap operation environment, such as laser detuning noise, phonon frequency drift, pulse deformation noise and the like. Under the existing proper experimental parameters, the precision of the quantum bit gate realized by the control pulse generated by the scheme is high. Moreover, even in a larger environmental noise range, the control pulse generated by the scheme can ensure the accuracy of the quantum bit operation of the ion trap so as to obtain the quantum bit gate with lower distortion. The scheme can provide a better physical control means for the ion trap quantum chip and the quantum computing task in the middle-scale noise quantum computing era.

The present disclosure is described in detail in two aspects below. The method comprises the following steps:

A first section that illustrates the core ideas and key steps of the disclosed solution;

The control pulse generation scheme for the ion qubit in the ion trap is low in distortion degree and high in environment noise interference resistance. Specifically, the present example symmetrically designs the amplitude slice and the phase slice of the ion trap Rabi frequency, and optimally generates the control pulse, so that the distortion of the multiple quantum bit gate based on the optimally generated control pulse can be at a very low level under various environmental noise. Ambient noise as referred to herein includes, but is not limited to, drift of laser detuning, drift of phonon frequency, micro-deformation of pulse slices, etc.; meanwhile, the real experimental indexes such as the vacuum cavity environment temperature of the ion trap operation and the like are fully considered in the method, and the generated control pulse is closer to the working experimental environment of a real ion trap quantum computer. In addition, after decoding the generated control pulse (for example, decoding by an acousto-optic modulator, etc.), the control pulse can be conveniently input to a real ion trap quantum computer, and the operation accuracy of the ion trap quantum computer can be well controlled, so that a foundation is laid for accurately completing a quantum computing task.

This example may be implemented through software platform simulation, as shown in fig. 4 (a), and the specific steps are as follows:

Step 1: acquiring parameter information of an ion trap required for realizing a target qubit gate, wherein the target qubit gate can be a native quantum gate which can be realized by the ion trap, and the like; the parameter information includes at least information of an ion qubit (i.e., a preset ion qubit) for realizing a target qubit gate.

For example, the above parameter information can be obtained in two ways, one way is that a pulse measuring ion trap chip parameter calculation module is called to calculate the parameter information of the ion trap needed to realize the target quantum bit gate; and in a second mode, laboratory measurement is carried out on the ion trap under the experimental condition of the laboratory by an experimenter to obtain parameter information, and the obtained parameter information is input. Based on the above, the specific step of step 1 is to determine whether to call the pulse ion trap chip parameter calculation module, if yes, obtain the required parameter information of the ion trap based on the pulse ion trap chip parameter calculation module, otherwise, input the parameter information obtained by laboratory measurement.

In practical application, the ion trap may include a plurality of ion qubits, but not all the ion qubits need to participate in the quantum operation to realize the target qubit gate, at this time, the ion qubit to be subjected to the quantum operation may be designated, for example, if the target qubit gate to be realized is a two-qubit gate, at this time, two ion qubits may be designated as preset ion qubits, so as to simulate the process of obtaining the target qubit gate after applying the control pulse to the preset ion qubit.

Step 2: adjusting the amplitude and phase of the control pulse while maintaining a symmetrical relationship of the amplitude and phase; specifically, for the first iteration step, the amplitude Ω (t) and the phase Φ (t) of the initial rad (Rabi) frequency of the laser are symmetrically processed. Specifically, N amplitude slices are obtained by performing symmetric processing on the amplitudes, and N phase slices are obtained by performing anti-symmetric processing on the phases. For the non-first iteration step, after adjusting the amplitude and phase of the control pulse (i.e. adjusting the values of the amplitude slice and the phase slice of the pulse), it is further required to determine whether the adjusted amplitude and phase satisfy the following symmetry relationship, if so, step 3 is entered; otherwise, the mapping into a symmetrical pulse form is based on the following manner.

Here, the Rabi frequency refers to an equivalent pulse generated by two coherent laser signals.

For example, the amplitude and phase equally dividing slices are divided into N preset waveforms (for example, square wave forms, and other waveform forms can be adopted in practical application, which are not limited in this example), and at this time, the conditions required to be satisfied by the amplitude slice and the phase slice are:

the amplitude slice satisfies the form: omega ₁＝Ω_N,…,Ω_i＝Ω_N-i+1;

phase slicing satisfies the form: phi ₁＝-φ_N,…,φ_i＝-φ_N-i+1.

Wherein the N is adjusted with the number of ion qubits in the ion trap. In a specific example, the N is linearly positively correlated with the number of ion qubits in the ion trap, for example, for 5 ion qubits, the N may take a value of 10; for 10 ion qubits, the N may take on any number from 15 to 20.

It will be appreciated that the maximum power of a laser, such as an ion trap control laser, is limited, and the following conditions are also required to be satisfied in practical applications:

Amplitude slicing is required to satisfy: omega _i＝1,...,N∈(0,Ω_max ];

Phase slicing needs to satisfy phi _i = 1, …, N e (-pi, pi).

It is understood that i described above is an integer of 1 or more and N or less.

Step 3: the pulse sequence formed by the amplitude slice and the phase slice obtained after the slicing processing is input into a phonon-ion coupling equation and an ion-ion coupling equation, and meanwhile, environmental noise is ignored, and an approximate qubit gate U ^αU^β (namely the first approximate qubit gate) which can be realized by the initial Rabi frequency is obtained through simulation.

Wherein, the U ^α can be obtained based on the following phonon-ion coupling equation:

Here, i in the formula (1) represents an imaginary number; the U ^α represents the sum of entanglement degrees of all phonons in the ion trap and all ion qubits (namely preset ion qubits) needing quantum operation in the ion trap; the eta _j,k represents the coupling strength of the ion quantum bit with the number j and the phonon with the number k; the omega _j (t) represents an amplitude slice corresponding to the ion qubit with the number j; phi _j (t) represents a phase slice corresponding to the ion qubit with the number j; the ω _k characterizes the frequency of the phonons denoted k; μ represents the amount of detuning of the laser signal; the said Characterizing the ambient noise in which the ion trap is located; the a _k characterizes the annihilation operator of the phonon numbered k; the saidThe ion qubit, denoted j, is rotated around the XY plane by the Pauli matrix of angle ψ.

In practical applications, for an ion chain formed by ion qubits in an ion trap, the ion qubits on the ion chain can be numbered according to a certain sequence, such as from left to right, and similarly, phonons for transferring quantum information between the ion qubits can also be numbered, so that subsequent operations are facilitated. It should be noted that, the specific numbering mode is not limited in this example, and may be set by itself based on actual habits.

The U ^β can be derived based on the following ion-ion coupling equation:

Here, i in the formula (2) represents an imaginary number; the U ^β represents the sum of entanglement degrees between every two ion quantum bits needing quantum operation in the ion trap; the eta _j,k represents the coupling strength of the ion quantum bit with the number j and the phonon with the number k; the eta _m,k represents the coupling strength of an ion quantum bit with the number of m and a phonon with the number of k; the omega _j (t) represents an amplitude slice corresponding to the ion qubit with the number j; the omega _m (t) represents an amplitude slice corresponding to an ion qubit with the number of m; the ω _k characterizes the frequency of the phonons denoted k; the mu represents the detuning amount of the laser signal; the said Characterizing the ambient noise in which the ion trap is located; phi _m(t₂) represents a phase slice corresponding to an ion qubit with the number of m; phi _j(t₁) represents a phase slice corresponding to the ion qubit with the number j; the saidCharacterizing Pauli matrix of ion quantum bit with number j rotating psi angle around XY plane; the saidThe ion qubit, numbered m, is characterized by a Pauli matrix rotated around the XY plane by an angle ψ.

Step 4: simulating to obtain the distortion degree of the approximate quantum bit gate U ^αU^β obtained in the step 3 under the condition of no environmental noise; for example, the distortion degree may be calculated based on the following formula:

wherein the U _goal characterizes a target qubit gate.

Step 5: determining small-scale noise possibly generated by the ion trap quantum computer corresponding to the ion trap in the step 1 during operation to simulate the environmental noise, specifically, setting the environmental noise range, and assigning a value in the environmental noise rangeAnd (3) repeating the step (4) after the formula given in the step (3) is carried out, so as to recalculate the distortion degree in the environment noise range. And then executing the step 6 under the condition that the distortion degree does not meet the preset condition; otherwise, step 7 is performed.

For example, the environmental noise range may be set within [ a first noise value, a second noise value ], such as the first noise value range is [ -5,0 ], and the second noise value range is (0, 5], which is merely exemplary, and may be set based on actual scene requirements in practical applications. Further, determining the distortion degree obtained under the condition of the first noise value, determining the distortion degree obtained under the condition of the second noise value, and adding the distortion degrees obtained under the three scenes of environmental noiselessness, the first noise value and the second noise value to obtain the total distortion degree; at this time, in step 5, if the distortion degree does not meet the preset condition, or if the maximum number of iteration steps is not reached, step 6 is executed; otherwise, the executing step 7 may specifically be: executing the step 6 under the condition that the total distortion degree does not meet the preset condition or the condition that the maximum iteration step number is not reached; otherwise, step 7 is performed.

Step 6: and (3) adjusting the initial ratio (Rabi) frequency in the step (3) to obtain an adjusted Rabi frequency, and further, performing symmetrical processing on the amplitude and the phase of the adjusted Rabi frequency based on the manner described in the step (2), wherein the processing manner is similar to the step (2), and the details are omitted. Then, repeating steps 3 to 5 until the distortion degree (may also be the total distortion degree) meets a preset condition or the maximum iteration step number is reached, and taking the Rabi frequency (including amplitude and phase) at the moment, that is, the Rabi frequency (including amplitude and phase) corresponding to the distortion degree (may also be the total distortion degree) meeting the preset condition as the target pulse sequence.

Step 7: and taking the Rabi frequency (including amplitude and phase) corresponding to the distortion degree (the total distortion degree) meeting the preset condition as a target pulse sequence for realizing the target quantum bit gate, and completing the flow.

At this time, the target pulse sequence obtained in the step 7 is applied to the ion trap described in the step 1 to obtain a target approximate qubit gate, and the target approximate qubit gate can be used as an approximate gate of the target qubit gate, and the distortion degree is low.

In practical application, the set environmental noise range can be further enlarged, and the distortion degree of the step 4 under different enlarged environmental noise is calculated, so that the environmental noise range which can be resisted by the target pulse sequence obtained through optimization under the example is verified, and the application range of the scheme, such as applicable scenes, is determined.

In this example, for step 1, the ion trap chip control parameter generating tool built in the current measuring pulse can be conveniently used, and the relevant parameters of the ion trap chip are obtained as the parameter information of step 1. Moreover, the scheme also supports experimental conditional user input of information of real ion trap quantum computing hardware. After the confirmation of the basic parameter information of the ion trap quantum computer is completed, namely, after the step 1, a user can conveniently generate control pulse slice information (namely, a target pulse sequence) with strong anti-environmental interference capability through the steps 2-7, and can test the anti-interference capability of the generated control pulse slice information on environmental noise so as to determine applicable scenes.

The resulting control pulse slices (i.e., the target pulse sequence) of this example are formed from amplitude slices and phase slices of the Rabi frequency, and can be implemented by acousto-optic modulators commonly used in the laboratory at the present time. The ion trap experimental device at the present stage can also control the environmental noise within the bearable range of the example through precise design, swing and regulation, in other words, the scheme of the example can be realized under the existing experimental conditions. Meanwhile, the method can ensure that the distortion degree of the obtained multi-bit quantum gate is at a lower level in a controllable environment noise range, and can be well applied to the task of the current ion trap quantum computation.

A second part: specific experiments demonstrate the effects and advantages of the disclosed scheme.

This example exemplifies an ion trap containing 8 ytterbium (yb+) ions; wherein the 8 ytterbium (Yb+) ions are arranged as one-dimensional linear chain chains, and the Yb+ ions are numbered from No. 1 to No. 8. Table 1 below shows information about parameters of the ion trap chip and the laser used in this example.

TABLE 1

Further, the number 1 and number 3 ion qubits are selected as preset ion qubits to be subjected to quantum operation, so as to obtain a double-qubit gate (namely a target qubit gate). As shown in table 2, and as shown in fig. 4 (b), compared to the qubit gate obtained in the prior art scheme, the qubit gate obtained by generating the control pulse in the present disclosure has a lower distortion degree under most ion trap experimental parameters (the laser detuning drift amount is taken as an example in this example).

TABLE 2

Thus, compared to existing ion trap control pulse generation schemes, the disclosed scheme has significant advantages:

First, interference immunity is strong: the scheme adopts the design thought of symmetrical pulse, and the control pulse slice obtained by optimization under different parameters has strong anti-interference capability on various environmental noises. The disclosed scheme can ensure that the distortion degree of the obtained multi-quantum bit gate (such as a double-quantum bit gate) is at a very low level in the noise range of a common laser, the controllable laser pulse deformation and the phonon frequency drift range caused by an ion trap environment.

Second, the scalability is strong: according to the scheme, for ion traps with different structures, the number N of slices is only in linear relation with the number of ion qubits in the ion trap, so that the scheme is applicable to large-scale ion trap chip structures. Moreover, since the number of slices N is in linear positive correlation with the number of ion qubits in the ion trap, the scheme disclosed by the invention can be further popularized to a pulse generation scheme of parallel multi-quantum bit gates in the ion trap, and the application range and the scalability are strong.

Third, the hardware performance requirements are low: the pulse intensity required in the scheme can be limited to be more close to the power range of a real laser, and meanwhile, the phase slice can be kept within 2 pi, so that the method is suitable for the working conditions of a common laser.

Fourth, the availability is strong: the scheme has low sensitivity to time and laser detuning of the quantum bit gate, can effectively work under most ion trap chips, and simultaneously fully considers environmental noise such as ion trap working environment temperature and the like, and has stronger usability.

The disclosed scheme also provides a pulse sequence generating device based on the ion trap, as shown in fig. 5, comprising:

A pulse sequence generating unit 501, configured to determine a number N of slices required for slicing an amplitude and a phase of a current laser signal, and perform slicing processing to obtain a first symmetric pulse sequence formed by N amplitude slices and N phase slices; wherein the N amplitude slices satisfy a first symmetry, and the N phase slices satisfy a second symmetry; n is an integer greater than or equal to 2;

The simulation calculation unit 502 is configured to simulate the first symmetric pulse sequence to be applied to a preset ion qubit of the ion trap, so as to obtain a first approximate qubit gate;

And a result output unit 503, configured to take the current first symmetric pulse sequence as a target pulse sequence when at least the degree of difference between the first approximate qubit gate and the target qubit gate meets a preset condition.

In a specific example of the present disclosure, further comprising: updating the adjusting unit; wherein,

The updating and adjusting unit is used for adjusting the amplitude and the phase of the current laser signal to update the first symmetrical pulse sequence under the condition that the difference degree between the first approximate quantum bit gate and the target quantum bit gate does not meet the preset condition;

The simulation calculation unit is further configured to simulate, again after the updating of the first symmetric pulse sequence is completed, the first symmetric pulse sequence to be applied to a preset ion qubit of the ion trap, so as to obtain a first approximate qubit gate again, until at least a degree of difference between the first approximate qubit gate and a target qubit gate meets a preset condition.

In a specific example of the present disclosure, further comprising: a parameter acquisition unit; wherein,

The parameter acquisition unit is used for acquiring parameter information of the ion trap required by realizing the target quantum bit gate;

The pulse sequence generating unit is specifically configured to determine, based on the parameter information, a slice number N required for slicing an amplitude and a phase of a current laser signal.

In a specific example of the disclosed aspects, the parameter information characterizes at least a number of ion qubits in the ion trap; wherein,

The pulse sequence generating unit is specifically configured to determine, based at least on the number of ion qubits in the ion trap, a slice number N required for slicing the amplitude and phase of the current laser signal.

In a specific example of the disclosed arrangement, the number of slices N is linearly positively correlated with the number of ion qubits in the ion trap.

In a specific example of the disclosed aspect, the N amplitude slices satisfy a first symmetry relationship, including:

Ω₁＝Ω_N,…,Ω_i＝Ω_N-i+1；

Wherein, omega i represents the i-th amplitude slice, i is an integer which is more than or equal to 1 and less than or equal to N.

In a specific example of the solution of the present disclosure, the N phase slices satisfy a second symmetry relationship, including:

φ₁＝-φ_N,…,φ_i＝-φ_N-i+1；

wherein phi represents an ith phase slice, and i is an integer greater than or equal to 1 and less than or equal to N.

In a specific example of the solution of the present disclosure, the analog calculation unit is specifically configured to simulate the first symmetric pulse sequence being applied to a preset ion qubit of an ion trap, and obtain a first approximate qubit gate when it is simulated that no ambient noise exists around the ion trap.

In a specific example of the present disclosure, further comprising: a noise estimation unit; wherein,

The noise estimating unit is used for estimating an environmental noise range around the ion trap, wherein the environmental noise range represents that the environmental noise around the ion trap is larger than or equal to a first noise value and smaller than or equal to a second noise value, and the first noise value is smaller than the second noise value;

The simulation calculation unit is further used for simulating preset ion qubits applied to the ion trap by the first symmetrical pulse sequence and obtaining a second approximate qubit gate under the condition that the ion trap is simulated to be at the first noise value; determining a degree of difference between the second approximate qubit gate and the target qubit gate; obtaining a target degree of difference based at least on the degree of difference between the second approximate qubit gate and the target qubit gate, and the degree of difference between the first approximate qubit gate and the target qubit gate;

The result output unit is further used for determining that the target difference degree meets a preset condition.

In a specific example of the disclosed solution, wherein,

The simulation calculation unit is further configured to simulate a preset ion qubit applied to an ion trap by the first symmetric pulse sequence, and simulate that the ion trap is at the second noise value, so as to obtain a third approximate qubit gate; determining a degree of difference between the third approximate qubit gate and the target qubit gate; obtaining a target degree of difference based at least on the degree of difference between the third approximate qubit gate and the target qubit gate, and the degree of difference between the first approximate qubit gate and the target qubit gate;

In a specific example of the disclosed solution, wherein,

The simulation calculation unit is further used for simulating preset ion qubits applied to the ion trap by the first symmetrical pulse sequence and obtaining a second approximate qubit gate under the condition that the ion trap is simulated to be at the first noise value; determining a degree of difference between the second approximate qubit gate and the target qubit gate; simulating a preset ion qubit applied to an ion trap by the first symmetrical pulse sequence, and obtaining a third approximate qubit gate under the condition that the ion trap is simulated to be at the second noise value; determining a degree of difference between the third approximate qubit gate and the target qubit gate; obtaining a target degree of difference based at least on the degree of difference between the first approximate qubit gate and the target qubit gate, the degree of difference between the second approximate qubit gate and the target qubit gate, and the degree of difference between the third approximate qubit gate and the target qubit gate;

In a specific example of the present disclosure, further comprising:

A verification unit configured to adjust the ambient noise range to reduce the first noise value and increase the second noise value; and under the condition that the range of the environmental noise is enlarged, the target difference degree is obtained again so as to verify whether the target difference degree meets the preset condition.

In a specific example of the disclosed aspects, the target qubit gate is a native quantum gate that can be realized by the ion trap.

In a specific example of the disclosed scheme, the target qubit gate is a two-qubit gate, or a multiple-qubit gate.

The specific functions of each unit in the above device may be described with reference to the above method, and will not be described herein.

According to embodiments of the present disclosure, the present disclosure also provides an electronic device, a readable storage medium and a computer program product.

Fig. 6 illustrates a schematic block diagram of an example electronic device 600 that may 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 telephones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions, are meant to be exemplary only, and are not meant to limit implementations of the disclosure described and/or claimed herein.

As shown in fig. 6, the apparatus 600 includes a computing unit 601 that can perform various appropriate actions and processes according to a computer program stored in a Read Only Memory (ROM) 602 or a computer program loaded from a storage unit 608 into a Random Access Memory (RAM) 603. In the RAM 603, various programs and data required for the operation of the device 600 may also be stored. The computing unit 601, ROM 602, and RAM 603 are connected to each other by a bus 604. An input/output (I/O) interface 605 is also connected to bus 604.

Various components in the device 600 are connected to the I/O interface 605, including: an input unit 606 such as a keyboard, mouse, etc.; an output unit 607 such as various types of displays, speakers, and the like; a storage unit 608, such as a magnetic disk, optical disk, or the like; and a communication unit 609 such as a network card, modem, wireless communication transceiver, etc. The communication unit 609 allows the device 600 to exchange information/data with other devices via a computer network, such as the internet, and/or various telecommunication networks.

The computing unit 601 may be a variety of general and/or special purpose processing components having processing and computing capabilities. Some examples of computing unit 601 include, but are not limited to, a Central Processing Unit (CPU), a Graphics Processing Unit (GPU), various specialized Artificial Intelligence (AI) computing chips, various computing units running machine learning model algorithms, a Digital Signal Processor (DSP), and any suitable processor, controller, microcontroller, etc. The computing unit 601 performs the various methods and processes described above, such as ion trap based pulse train generation methods. For example, in some embodiments, the ion trap based pulse train generation method may be implemented as a computer software program tangibly embodied on a machine-readable medium, such as storage unit 608. In some embodiments, part or all of the computer program may be loaded and/or installed onto the device 600 via the ROM 602 and/or the communication unit 609. When a computer program is loaded into RAM 603 and executed by computing unit 601, one or more steps of the ion trap-based pulse sequence generation method described above may be performed. Alternatively, in other embodiments, the computing unit 601 may be configured to perform the ion trap based pulse train generation method in any other suitable manner (e.g., by means of firmware).

Various implementations of the systems and techniques described here above may be implemented in digital electronic circuitry, integrated circuit systems, field Programmable Gate Arrays (FPGAs), application Specific Integrated Circuits (ASICs), application Specific Standard Products (ASSPs), systems On 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, the one or more computer programs may be executed and/or interpreted on a programmable system including at least one programmable processor, which may be a special purpose or general-purpose programmable processor, that may receive data and instructions from, and transmit data and instructions to, a storage system, at least one input device, and at least one output device.

Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program code 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 code, when executed by the processor or controller, causes the functions/operations specified in the flowchart and/or block diagram to be implemented. 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. The 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 pointing device (e.g., a mouse or 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 may 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 background 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 background, 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 a client and a server. The client and server are typically 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. The server may be a cloud server, a server of a distributed system, or a server incorporating a blockchain.

It should be appreciated that various forms of the flows shown above may be used to reorder, add, or delete steps. For example, the steps recited in the present disclosure may be performed in parallel, sequentially, or in a different order, provided that the desired results of the disclosed aspects are achieved, and are not limited herein.

The above detailed description should not be taken as limiting the scope of the present disclosure. It will be apparent to those skilled in the art that various modifications, combinations, sub-combinations and alternatives are possible, depending on design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present disclosure are intended to be included within the scope of the present disclosure.

Claims

1. A pulse train generation method based on an ion trap, comprising:

Taking the current first symmetrical pulse sequence as a target pulse sequence under the condition that at least the difference degree between the first approximate qubit gate and the target qubit gate meets a preset condition; the target quantum bit gate is a native quantum gate which can be realized by the ion trap;

Wherein simulating the first symmetric pulse sequence to be applied to a preset ion qubit of the ion trap to obtain a first approximate qubit gate comprises:

And simulating that the first symmetrical pulse sequence is applied to preset ion qubits of the ion trap, and obtaining a first approximate qubit gate under the condition that the surrounding of the ion trap is simulated to be free of environmental noise.

2. The method of claim 1, further comprising:

Under the condition that the difference degree between the first approximate qubit gate and the target qubit gate does not meet the preset condition, adjusting the amplitude and the phase of the current laser signal to update the first symmetrical pulse sequence;

and after the first symmetrical pulse sequence is updated, simulating the first symmetrical pulse sequence to be applied to preset ion qubits of an ion trap again so as to obtain a first approximate qubit gate again until at least the difference degree between the first approximate qubit gate and the target qubit gate meets preset conditions.

3. The method of claim 1, further comprising:

acquiring parameter information of an ion trap required for realizing the target qubit gate;

Wherein the determining the number of slices N required for slicing the amplitude and phase of the current laser signal includes:

based on the parameter information, the number of slices N required for slicing the amplitude and phase of the current laser signal is determined.

4. A method according to claim 3, the parameter information characterizing at least the number of ion qubits in the ion trap; wherein,

The determining, based on the parameter information, the number of slices N required for slicing the amplitude and phase of the current laser signal includes:

Based at least on the number of ion qubits in the ion trap, a number of slices N required to slice the amplitude and phase of the current laser signal is determined.

5. The method of claim 4, wherein the slice number N is linearly positively correlated with the number of ion qubits in the ion trap.

6. The method of any of claims 1-5, wherein the N amplitude slices satisfy a first symmetry relationship, comprising:

；

Wherein Ω _i characterizes an i-th amplitude slice, where i is an integer greater than or equal to 1 and less than or equal to N.

7. The method of any of claims 1 to 5, wherein the N phase slices satisfy a second symmetry relationship, comprising:

；

Wherein, ϕ _i characterizes the ith phase slice, i is an integer greater than or equal to 1 and less than or equal to N.

8. The method of claim 1, further comprising:

Obtaining a target degree of difference based at least on the degree of difference between the second approximate qubit gate and the target qubit gate, and the degree of difference between the first approximate qubit gate and the target qubit gate;

the target difference degree meets a preset condition.

9. The method of claim 1, further comprising:

Obtaining a target degree of difference based at least on the degree of difference between the third approximate qubit gate and the target qubit gate, and the degree of difference between the first approximate qubit gate and the target qubit gate;

the target difference degree meets a preset condition.

10. The method of claim 1, further comprising:

Obtaining a target degree of difference based at least on the degree of difference between the first approximate qubit gate and the target qubit gate, the degree of difference between the second approximate qubit gate and the target qubit gate, and the degree of difference between the third approximate qubit gate and the target qubit gate;

the target difference degree meets a preset condition.

11. The method of any of claims 8 to 10, further comprising:

adjusting the ambient noise range to reduce the first noise value and to increase the second noise value;

And under the condition that the range of the environmental noise is enlarged, the target difference degree is obtained again so as to verify whether the target difference degree meets the preset condition.

12. The method of any one of claims 1 to 5, wherein the target qubit gate is a two-qubit gate, or a multiple-qubit gate.

13. A pulse sequence control method based on an ion trap, comprising:

Applying a target pulse sequence to a preset ion qubit of an ion trap; wherein the target pulse sequence is the pulse sequence obtained in any one of claims 1 to 12;

14. An ion trap based pulse train generation apparatus comprising:

a result output unit, configured to take the current first symmetric pulse sequence as a target pulse sequence when at least the degree of difference between the first approximate qubit gate and the target qubit gate satisfies a preset condition; the target quantum bit gate is a native quantum gate which can be realized by the ion trap;

the simulation calculation unit is specifically configured to simulate the first symmetric pulse sequence to be applied to a preset ion qubit of an ion trap, and obtain a first approximate qubit gate when it is simulated that no environmental noise exists around the ion trap.

15. The apparatus of claim 14, further comprising: updating the adjusting unit; wherein,

16. The apparatus of claim 14, further comprising: a parameter acquisition unit; wherein,

17. The apparatus of claim 16, the parameter information characterizing at least a number of ion qubits in the ion trap; wherein,

18. The apparatus of claim 17, wherein the slice number N is linearly positively correlated with the number of ion qubits in the ion trap.

19. The apparatus of any of claims 14 to 18, wherein the N amplitude slices satisfy a first symmetry relationship, comprising:

；

20. The apparatus of any of claims 14 to 18, wherein the N phase slices satisfy a second symmetry relationship, comprising:

；

21. The apparatus of claim 14, further comprising: a noise estimation unit; wherein,

22. The apparatus of claim 14, further comprising: a noise estimation unit; wherein,

23. The apparatus of claim 14, further comprising: a noise estimation unit; wherein,

24. The apparatus of any of claims 21 to 23, further comprising:

25. The apparatus of any of claims 14 to 18, wherein the target qubit gate is a two-qubit gate, or a multiple-qubit gate.

26. An ion trap based pulse train control system comprising:

An ion trap;

A laser transmitter for applying a target pulse sequence to a predetermined ion qubit of the ion trap; wherein the target pulse sequence is the pulse sequence obtained in any one of claims 1 to 12;

27. An electronic device, comprising:

at least one processor; and

A memory communicatively coupled to the at least one processor; wherein,

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 1-12.

28. A non-transitory computer readable storage medium storing computer instructions for causing the computer to perform the method of any one of claims 1-12.

29. A computer program product comprising a computer program which, when executed by a processor, implements the method according to any of claims 1-12.