Ion control method and device, ion trap system and related device

Abstract

The invention discloses an ion control method and device, an ion trap system and a related device, and belongs to the technical field of quantum information. A plurality of ions in the ion trap system are in a magnetic field with a magnetic field gradient, the magnetic field gradient enables transition frequencies of the plurality of ions to be different, and each ion is of a multi-energy-level structure. The method comprises the steps that according to the transition frequency of a plurality of first ions, the energy level of the first ions is adjusted so that the first ions irrelevant to quantum control can be transferred from a calculation space to an auxiliary space, and the energy level of the ions in the calculation space is different from the energy level of the ions in the auxiliary space; and performing quantum manipulation on the plurality of second ions in the calculation space to form a plurality of quantum bits. According to the scheme, light finding of ions is not needed, light finding of ions is not needed, multi-ion control can be achieved through global laser or microwaves, and implementation is easy. And moreover, multi-ion control can be realized by using a relatively small magnetic field gradient, and the ion control threshold is reduced.

Description

Technical Field

[0001] The present application relates to the field of quantum information technology, and particularly relates to an ion manipulation method, device, ion trap system and related devices. Background Art

[0002] Currently, quantum information technology has become an important research direction in the development of information technology. Quantum information technology is widely applied in fields such as quantum computing, quantum simulation, quantum sensing, and precision measurement. A key point of quantum information technology lies in quantum manipulation. The realization of quantum manipulation depends on an ion trap system, which is used to confine ions in a limited space and utilize a specific electromagnetic field to constrain the movement of ions, so as to form quantum bits carrying information by manipulating the ions.

[0003] Related technologies provide two methods for manipulating ions. The first method is realized based on ion transport technology, that is, ions find light. In this method, a chip structure with multiple electrodes is fabricated by means of micro-nano processing, and a voltage signal varying with time is applied to the multiple electrodes. The voltage signal is used to achieve the movement of ions in space, transport the ions to the specified manipulation light range, and then realize the logical manipulation of the ions. The second method is realized based on the spatial focusing technology of laser, that is, the technology of light finding ions. In this method, the laser is focused by optical means to a diameter smaller than the ion spacing. When performing quantum operations, the laser on a specific ion is turned on within a specific time period, and the logical manipulation of the specific ion can be realized.

[0004] However, the above first method requires very complex micro-nano processing technology, and the chip processing process is complex. The above second method has very high requirements for the diffraction limit of laser focusing and also has very high requirements for the pointing stability of the laser. It is difficult to implement and the system stability is poor. Summary of the Invention

[0005] The present application provides an ion manipulation method, device, ion trap system and related devices, which do not require complex chip processing means, do not require laser strong focusing technology, have lower requirements for the pointing stability of the laser, are easy to implement, and lower the threshold of ion manipulation. The technical solutions are as follows:

[0006] In a first aspect, an ion manipulation method is provided, which is applied to an ion trap system. The ion trap system includes a plurality of ions, and the plurality of ions are in a magnetic field with a magnetic field gradient, which causes the transition frequencies of the plurality of ions to be different. Each ion in the plurality of ions has a multi-level structure. The method includes: adjusting the energy levels of the plurality of first ions according to the transition frequencies of the plurality of first ions, so as to transfer the plurality of first ions from the computational space to the auxiliary space. The above-mentioned plurality of ions include the plurality of first ions, and the energy levels of the ions in the computational space are different from those of the ions in the auxiliary space; performing quantum manipulation on a plurality of second ions in the computational space to form a plurality of qubits, where the plurality of second ions are the ions other than the plurality of first ions among the above-mentioned plurality of ions.

[0007] In this solution, by adjusting the energy levels of the ions, the ions irrelevant to quantum manipulation are transferred to the auxiliary space, and quantum manipulation is performed on the ions in the computational space. It can be seen that this solution does not require the ions to find light, that is, no complex chip processing means are required. This solution also does not require light to find ions, that is, no laser strong focusing technology is required, and the requirement for the pointing stability of the laser is relatively low. And due to the spatial transfer, this solution can achieve multi-ion manipulation with a smaller magnetic field gradient, greatly reducing the threshold of ion manipulation, increasing the number of manipulated ions while ensuring a relatively high fidelity, and providing a new idea for quantum information processing.

[0008] Among them, performing quantum manipulation on a plurality of second ions in the computational space includes: performing quantum manipulation on the plurality of second ions by using a global laser and / or a global microwave. That is, this solution can achieve multi-ion manipulation by using a global laser or microwave, which is easy to implement, and the system stability can be ensured without laser strong focusing.

[0009] Among them, adjusting the energy levels of the plurality of first ions according to the transition frequencies of the plurality of first ions, so as to transfer the plurality of first ions from the computational space to the auxiliary space, includes: generating a first manipulation signal according to the transition frequencies of the plurality of first ions, and the first manipulation signal has a plurality of frequencies matching the transition frequencies of the plurality of first ions; using the first manipulation signal to control the plurality of first ions to perform energy level transitions, so as to transfer the plurality of first ions from the computational space to the auxiliary space.

[0010] Among them, the first manipulation signal includes a first laser signal and / or a first microwave signal.

[0011] Optionally, the number of the plurality of second ions is 2, and the quantum manipulation includes quantum entanglement operation; performing quantum manipulation on the plurality of second ions in the computational space includes: performing quantum entanglement operation on the plurality of second ions at a first angle, where the first angle is a times the angle required for two-bit entanglement, and a is greater than 0 and less than 1; respectively performing single-bit flip operations on the plurality of second ions after the quantum entanglement operation; and performing quantum entanglement operation on the plurality of second ions after the single-bit flip operation again at a second angle, where the sum of the second angle and the first angle is equal to the angle required for two-bit entanglement. That is, in this solution, the error caused by the difference in ion transition frequencies is eliminated through the middle single-bit flip operation combined with the two two-bit quantum entanglement operations before and after.

[0012] Optionally, a is 0.5.

[0013] After performing quantum manipulation on the plurality of second ions in the computational space to form a plurality of qubits, it further includes: adjusting the energy levels of the plurality of first ions according to the transition frequencies of the plurality of first ions to transfer the plurality of first ions from the auxiliary space back to the computational space. That is, after each quantum manipulation through space transfer, the ions transferred to the auxiliary space need to be transferred back to facilitate the next quantum manipulation.

[0014] Optionally, the above-mentioned multi-energy levels include at least four sub-energy levels, the computational space corresponds to two first sub-energy levels among the at least four sub-energy levels, the auxiliary space corresponds to two second sub-energy levels among the at least four sub-energy levels, the two first sub-energy levels are any two sub-energy levels among the at least four sub-energy levels, and the two second sub-energy levels are any two sub-energy levels among the at least four sub-energy levels other than the two first sub-energy levels.

[0015] Optionally, the above-mentioned multi-energy levels include a ground state energy level, a steady state energy level, and a metastable state energy level, and any one of the at least four sub-energy levels is a sub-energy level in the ground state energy level or a sub-energy level in the steady state energy level or a sub-energy level in the metastable state energy level.

[0016] Among them, the above-mentioned plurality of ions includes a plurality of identical ions.

[0017] In a second aspect, an ion manipulation device is provided, and the ion manipulation device has a function of implementing the behavior of the ion manipulation method in the first aspect above. The ion manipulation device includes one or more modules, and the one or more modules are used to implement the ion manipulation method provided in the first aspect above.

[0018] In a third aspect, an ion trap system is provided. The ion trap system includes a plurality of ions that are in a magnetic field with a magnetic field gradient, and the magnetic field gradient causes the transition frequencies of the plurality of ions to be different. Each ion in the plurality of ions has a multi-level structure; the ion trap system is used to implement the ion manipulation method provided in the first aspect above.

[0019] In a fourth aspect, a manipulation device is provided. The manipulation device includes a processor and a memory. The memory is used to store a program for executing the ion manipulation method provided in the first aspect above, and to store data related to implementing the ion manipulation method provided in the first aspect above. The processor is configured to execute the program stored in the memory. The manipulation device may further include a communication bus, and the communication bus is used to establish a connection between the processor and the memory.

[0020] In a fifth aspect, a computer-readable storage medium is provided. Instructions are stored in the computer-readable storage medium, and when the instructions are run on a computer, the computer is caused to execute the ion manipulation method described in the first aspect above.

[0021] In a sixth aspect, a computer program product including instructions is provided. When the computer program product is run on a computer, the computer is caused to execute the ion manipulation method described in the first aspect above.

[0022] The technical effects obtained in the second to sixth aspects above are similar to those obtained by the corresponding technical means in the first aspect, and will not be elaborated here. Description of the Drawings

[0023] Figure 1 is a system architecture diagram related to an ion manipulation method provided by an embodiment of the present application;

[0024] Figure 2 is another system architecture diagram related to an ion manipulation method provided by an embodiment of the present application;

[0025] Figure 3 is a schematic structural diagram of an electronic device provided by an embodiment of the present application;

[0026] Figure 4 is a flowchart of an ion manipulation method provided by an embodiment of the present application;

[0027] Figure 5 is a combined schematic diagram of a computational space and an auxiliary space provided by an embodiment of the present application;

[0028] Figure 6 is a flowchart of another quantum manipulation method provided by an embodiment of the present application;

[0029] Figure 7It is a schematic diagram of ion manipulation provided by an embodiment of the present application;

[0030] Figure 8 It is a schematic diagram of a global laser provided by an embodiment of the present application;

[0031] Figure 9 It is a schematic diagram of a two-bit quantum manipulation provided by an embodiment of the present application;

[0032] Figure 10 It is a schematic diagram of a two-dimensional ion crystal in a magnetic field with a magnetic field gradient;

[0033] Figure 11 It is a difference diagram of the transition frequencies of multiple ions in a two-dimensional ion crystal provided by an embodiment of the present application;

[0034] Figure 12 It is a schematic structural diagram of an ion manipulation device provided by an embodiment of the present application. Detailed implementation manners

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the following will further describe the embodiments of the present application in detail with reference to the accompanying drawings.

[0036] For ease of understanding, some terms related to the embodiments of the present application will be explained first.

[0037] Multi-level structure of ions: The fact that an ion has a multi-level structure means that the electrons in the ion are distributed on multiple energy levels, and each energy level has a certain energy and electron distribution. The multi-level structure of ions includes the ground state, excited state, and metastable state. The ground state refers to the state where the electrons of the ion are in the lowest energy state, the excited state refers to the state where the electrons of the ion are in a higher energy state, and the metastable state refers to the state where the electrons of the ion are between the ground state and the excited state. The energy level structure of an ion includes multiple energy levels, and each energy level can have multiple sub-energy levels. The energy level state of the ion can transition between multiple sub-energy levels or between multiple energy levels. Energy level transition refers to the transition of an electron from one energy level to another, accompanied by the absorption or release of energy.

[0038] Zeeman state: It refers to the energy levels formed inside an ion due to angular momentum coupling, and the formation of the energy levels is due to the energy level splitting caused by an external magnetic field. The energy of the energy levels will change with the magnitude of the external magnetic field (generally first-order sensitive).

[0039] Geometric-phase gate: In an ion trap system, it refers to a scheme for realizing multi-bit entanglement of two or more ions by means of the harmonic oscillators generated by the Coulomb interaction between the ions. Generally, there are two implementation methods: molmer-sorensen gate (abbreviated as MS) and light-shift gate (abbreviated as LS). The fidelity of these two schemes is very high in actual use, and they are currently the mainstream schemes in the industry.

[0040] Identical ions: Ions of the same isotope of the same element. The ion trap system includes multiple identical ions, such as multiple Ca-40, or multiple Yb-171, or multiple Ba-133.

[0041] Next, the relevant background of the embodiments of the present application will be introduced.

[0042] Quantum computing benefits from the quantum superposition and entanglement properties and shows great potential in improving computing power (providing the ability of parallel computing), making it a hot field in current frontier research. As a popular candidate platform for general-purpose quantum computers, the ion trap system still faces many technical challenges and difficulties, and continuous research and exploration are needed to achieve the commercial application of quantum computing. To improve the performance of the quantum system, we mainly focus on increasing the number of qubits and the quality of quantum control. For the number of qubits, we generally encode the two-level system inside a single ion as a qubit. Therefore, the number of ions that can be controlled is linearly corresponding to the number of qubits. For the quality of quantum control, the ion trap system mainly uses the laser-assisted method to realize the coupling between qubits, but this method has relatively large errors and instabilities.

[0043] Here, we consider the two difficulties of the number of qubits and the quality of quantum control. This requires the processor to not only be able to load a large number of ions but also be able to achieve high-fidelity control of a large number of ions by adjusting the control field. So far, the number of ions that can be loaded inside a single processor has exceeded 1000, and the number of ions that can be independently controlled is about 30. Therefore, developing an efficient multi-ion independent control scheme inside a single processor has become a hot research topic.

[0044] The ion finding light technology provided in the related art requires very complex micro-nano processing technology, and the chip processing process is complex. Moreover, the light finding ion technology has very high requirements for the diffraction limit of laser focusing and also has very high requirements for the pointing stability of the laser. It is difficult to implement, and the system stability is poor.

[0045] In addition to the two schemes of ion seeking light and light seeking ion, currently, the independent manipulation of ions can also be achieved through a frequency addressing scheme. In the frequency addressing scheme, an external gradient control field (usually a magnetic field with a specific magnetic field gradient) is used to make the originally identical ions show a large frequency difference in space. Then, by applying a global laser or global microwave, the independent addressing of ions is achieved through frequency discrimination. Usually, a relatively large magnetic field gradient is required to make multiple ions in the ion trap system have an obvious frequency difference in space. For example, a magnetic field gradient of about 100 tesla per meter (T / m) is required to produce a frequency discrimination of the order of megahertz (MHz). To achieve a magnetic field gradient of 100 T / m, special magnetic field structure design is required, or a near-field microwave with a large current needs to be passed through the chip surface, and these are all relatively difficult to implement. In addition, when the frequency difference between two ions is obvious (i.e., relatively large), the currently widely used geometric phase gate is very difficult to implement or scale up in such an ion trap system, that is, it is relatively difficult to achieve multi-bit entanglement operations. Therefore, the number of ions that can be independently manipulated by this scheme is currently small.

[0046] This scheme aims at some problems in the related technology and provides a new ion manipulation method, which can realize the logical manipulation of multiple ions by using a global laser or global microwave under a small magnetic field gradient. Compared with the frequency addressing scheme in the related technology, this scheme can independently manipulate more ions under the same magnetic field gradient, that is, this scheme improves the number of manipulated ions on the premise of ensuring a high fidelity. In other words, this scheme improves the number of qubits while ensuring the quality of quantum manipulation, and realizes a higher fidelity manipulation of ions.

[0047] This scheme can be applied to various quantum information technologies, including quantum computing, quantum simulation, quantum sensing, precision measurement, etc.

[0048] Next, the implementation environment involved in the embodiments of this application will be introduced.

[0049] Figure 1 It is the system architecture diagram involved in an ion manipulation method provided by an embodiment of this application. This system can be called an ion trap system. See Figure 1 This system includes a laser, a modulator, a controller, an ion trap (not shown), and multiple ions. Among them, both the laser and the controller are connected to the modulator. The multiple ions are in a magnetic field with a magnetic field gradient, and the multiple ions are restricted in the limited space of the ion trap under the action of this magnetic field. Each ion in the multiple ions has a multi-level structure.

[0050] The laser is used to generate a first original laser signal and transmit the first original laser signal to the modulator. The controller is used to generate control signals of multiple frequencies and transmit the control signals of multiple frequencies to the modulator. The modulator is used to frequency-modulate the first original laser signal by the control signals of multiple frequencies to obtain a first manipulation signal, and use the first manipulation signal to control multiple first ions among the multiple ions to perform energy level transitions, so as to transfer the multiple first ions from the computational space to the auxiliary space. Among them, the multiple first ions are ions irrelevant to quantum manipulation, the energy levels of the ions in the computational space are different from those of the ions in the auxiliary space, and the multiple frequencies are frequencies matching the transition frequencies of the multiple first ions.

[0051] The laser is also used to generate a second original laser signal and transmit the second original laser signal to the modulator. The modulator is used to amplitude-modulate, phase-modulate or frequency-modulate the second original laser signal under the control of the controller to obtain a second manipulation signal, and use the second manipulation signal to perform quantum manipulation on multiple second ions in the computational space. Among them, the second manipulation signal is a global laser signal.

[0052] Among them, the laser can select a single-frequency laser with good coherence to output a laser signal of a specific wavelength. In order to achieve the energy level transition of the ions, the frequency of the laser signal output by the laser matches the transition frequency of the ions, so that the laser frequency resonates with the transition frequency of the ions. Of course, the laser can also select a tunable laser as long as it can output the required wavelength of the laser signal.

[0053] The modulator is an acousto-optic modulator (AOM) or an electro-optic modulator (EOM) or other forms of modulators. The modulator is mainly used to modulate the amplitude, frequency or phase of the received laser signal to obtain the laser signals required for quantum manipulation (such as ion initialization, quantum gates, quantum state readout, etc.), such as the first manipulation signal and the second manipulation signal mentioned above.

[0054] Optionally, the controller includes a timing control unit and a waveform control unit. The controller is used to generate control signals through the timing control unit and / or the waveform control unit. Among them, the timing control unit is used to turn the laser signal on and off in time according to the manipulation logic. The waveform control unit is used to control the modulator according to the specified quantum algorithm, including amplitude, phase and frequency control. When it comes to realizing space transfer through energy level transitions, the waveform control unit generates control signals of multiple frequencies, and the multiple frequencies match the transition frequencies of multiple first ions that need to perform energy level transitions.

[0055] Optionally, the controller includes one or more signal sources for generating control signals of multiple frequencies. Taking the example that the controller includes two signal sources, each of the two signal sources is used to generate control signals of partial frequencies. The controller further includes an adder, and the two parts of control signals of partial frequencies are superimposed by the adder and then transmitted to the modulator.

[0056] The above magnetic field gradient is generated by a permanent magnet or a current-carrying coil. Ions at different positions experience different magnetic fields, and this magnetic field gradient causes differences in the transition frequencies of ions at different positions. The above-mentioned multiple ions have a multi-level structure, and the transition frequencies between energy levels are sensitive to changes in the external magnetic field. In the embodiments of the present application, Zeeman energy levels are selected. The multi-level is generated by the angular momentum coupling of electrons or atomic nuclei inside the ions. The transition frequencies involved in this solution can refer to the optical band or the microwave band. It should be noted that if it is the microwave band, the above-mentioned laser needs to be replaced with a microwave device. In this solution, a calculation space and an auxiliary space are divided among the multiple sub-levels included in the multi-level. The calculation space is used for quantum information processing, that is, quantum manipulation, and the auxiliary space is used to carry ions that have nothing to do with quantum manipulation.

[0057] The above-mentioned multiple ions are identical ions. These multiple ions serve as information carriers in quantum information technology.

[0058] Optionally, the above-mentioned laser can be replaced with a microwave device, so as to use the microwave signal generated by the microwave device to achieve the space transfer and quantum manipulation in the above text. Or, a microwave device is added to the above system, that is, the system includes a laser and a microwave device, so as to jointly complete the space transfer and / or quantum manipulation in the above text by using the laser and the microwave device.

[0059] Figure 2 It is the system architecture diagram involved in another ion manipulation method provided by the embodiments of the present application. The system architecture includes a computing entity and a quantum computer. The computing entity is connected to the quantum computer in a wireless or wired manner. Optionally, the quantum computer includes Figure 1 the ion trap shown. Optionally, it further includes Figure 1 the laser, modulator and controller shown.

[0060] Among them, the computing entity is configured to receive the quantum information processing task input by the user and provide the quantum information processing task to the quantum computer. Optionally, the computing entity is further used to obtain the execution result of the quantum information processing task output by the quantum computer and display the output of the quantum computer to the user.

[0061] A quantum computer is used to execute a quantum information processing task input by a user by using the ion manipulation method provided by the embodiments of the present application. For example, the quantum computer determines the ions that need to be spatially transferred according to the quantum information processing task, adjusts the energy levels of these ions according to the transition frequencies of these ions, determines the operations to be performed on the ions in the computing space according to the quantum information processing task, and then performs corresponding operations on these ions, such as multi-bit quantum entanglement operations, single-bit flip operations, etc. Optionally, the quantum computer is also used to output the execution result of the quantum information processing task to a computing entity.

[0062] Please refer to Figure 3 , Figure 3 which is a schematic structural diagram of an electronic device shown according to the embodiments of the present application. The electronic device can be part or all of the computing entity shown in Figure 3 or can be part of a quantum computer. In one implementation, the electronic device includes one or more processors 301, a communication bus 302, a memory 303, and one or more communication interfaces 304.

[0063] The processor 301 is a general-purpose central processing unit (CPU), a network processor (NP), a microprocessor, or one or more integrated circuits for implementing the solution of the present application. For example, an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. Optionally, the above PLD is a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL), or any combination thereof.

[0064] The communication bus 302 is used to transmit information between the above components. Optionally, the communication bus 302 is divided into an address bus, a data bus, a control bus, etc. For the sake of representation, only a thick line is used in the figure, but it does not mean that there is only one bus or one type of bus.

[0065] Optionally, the memory 303 is a read-only memory (ROM), random access memory (RAM), electrically erasable programmable read-only memory (EEPROM), optical disc (including compact disc read-only memory (CD-ROM), compressed optical disc, laser disc, digital versatile disc, Blu-ray disc, etc.), magnetic disk storage medium, or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory 303 exists independently and is connected to the processor 301 through the communication bus 302, or the memory 303 is integrated with the processor 301.

[0066] The communication interface 304 uses any device such as a transceiver for communicating with other devices or communication networks. The communication interface 304 includes a wired communication interface, and optionally, also includes a wireless communication interface. Among them, the wired communication interface is, for example, an Ethernet interface, etc. Optionally, the Ethernet interface is an optical interface, an electrical interface, or a combination thereof. The wireless communication interface is a wireless local area networks (WLAN) interface, a cellular network communication interface, or a combination thereof, etc.

[0067] Optionally, in some embodiments, the electronic device includes multiple processors, such as Figure 3 the processor 301 and the processor 305 shown in. Each of these processors is a single-core processor or a multi-core processor. Optionally, the processor here refers to one or more devices, circuits, and / or processing cores for processing data (such as computer program instructions).

[0068] In a specific implementation, as an embodiment, the electronic device further includes an output device 306 and an input device 307. The output device 306 communicates with the processor 301 and can display information in various ways. For example, the output device 306 is a liquid crystal display (LCD), a light emitting diode (LED) display device, a cathode ray tube (CRT) display device, or a projector, etc. The input device 307 communicates with the processor 301 and can receive user input in various ways. For example, the input device 307 is a mouse, a keyboard, a touch screen device, or a sensing device, etc.

[0069] In some embodiments, the memory 303 is used to store the program code 310 for executing the solution of this application, and the processor 301 can execute the program code 310 stored in the memory 303. The program code includes one or more software modules. In the embodiments where the electronic device becomes part of a quantum computer, the electronic device can implement the ion manipulation method provided in the following Figure 4 embodiments through the processor 301 and the program code 310 in the memory 303.

[0070] It should be understood that the described implementation environment and business scenarios of the embodiments of this application are for more clearly explaining the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided by the embodiments of this application. Those of ordinary skill in the art know that with the evolution of the implementation environment and the emergence of new business scenarios, the technical solutions provided by the embodiments of this application are equally applicable to similar technical problems.

[0071] Next, the ion manipulation method provided by the embodiments of this application will be introduced.

[0072] Figure 4 is a flowchart of an ion manipulation method provided by the embodiments of this application. This method is applied to an ion trap system, which includes multiple ions. The multiple ions are in a magnetic field with a magnetic field gradient, and the magnetic field gradient causes the transition frequencies of the multiple ions to be different. Each ion in the multiple ions has a multi-level structure. Please refer to Figure 4 , and this method includes the following steps.

[0073] Step 401: Adjust the energy levels of the multiple first ions according to the transition frequencies of the multiple first ions to transfer the multiple first ions from the computational space to the auxiliary space. The ions in the computational space and the ions in the auxiliary space are at different energy levels.

[0074] Among them, the multiple ions in the ion trap system include multiple first ions, and the multiple first ions are ions irrelevant to the quantum manipulation in step 402. The multiple ions also include multiple second ions, and the multiple second ions are the ions to be subjected to the quantum manipulation in step 402.

[0075] As can be seen from the above, this solution uses the multi-level structure of ions for space transfer. In the embodiments of this application, the multi-level includes at least four sub-energy levels. The computational space corresponds to two first sub-energy levels among the at least four sub-energy levels, and the auxiliary space corresponds to two second sub-energy levels among the at least four sub-energy levels. These two first sub-energy levels are any two sub-energy levels among the at least four sub-energy levels, and these two second sub-energy levels are any two sub-energy levels among the at least four sub-energy levels other than the two first sub-energy levels. That is, any two sub-energy levels are selected from the multi-level to form the computational space, and any two other sub-energy levels are selected to form the auxiliary space.

[0076] Among them, the multi-level energy levels include a ground state energy level, a steady state energy level, and a metastable state energy level. Any one of the at least four sub-energy levels mentioned above is a sub-energy level in the ground state energy level, or a sub-energy level in the steady state energy level, or a sub-energy level in the metastable state energy level. For the convenience of description, the sub-energy levels included in the ground state energy level are called ground state sub-energy levels, the sub-energy levels included in the steady state energy level are called steady state sub-energy levels, and the sub-energy levels included in the metastable state energy level are called metastable state sub-energy levels.

[0077] In the embodiments of the present application, any four sub-energy levels are selected from the multi-level energy levels to form a computational space and an auxiliary space. Taking the multi-level energy levels including N sub-energy levels as an example, there are possible combination ways for the computational space and the auxiliary space.

[0078] In one way of energy level division, the multi-level energy levels include four energy levels of S, P, D, and F. Among them, the S energy level is the ground state energy level, the P energy level and the D energy level are metastable state energy levels, and the F energy level is the steady state energy level.

[0079] Taking the selection of four sub-energy levels from the S energy level and the D energy level to form a computational space and an auxiliary space as an example, the S energy level includes two sub-energy levels, and the D energy level includes five sub-energy levels. Then, there are possible combination ways for the computational space and the auxiliary space. Figure 5 Three of the combination ways are shown. In these three combination ways, the two sub-energy levels represented by Q0 and Q1 correspond to the computational space, and the two sub-energy levels represented by A0 and A1 correspond to the auxiliary space. In the first combination way, Q0 and Q1 respectively represent a sub-energy level in the S energy level and a sub-energy level in the D energy level, and A0 and A1 respectively represent another sub-energy level in the S energy level and another sub-energy level in the D energy level. In the second combination way, Q0 and Q1 represent two sub-energy levels in the S energy level, and A0 and A1 represent two sub-energy levels in the D energy level. In the third combination way, Q0 and Q1 respectively represent a sub-energy level in the S energy level and a sub-energy level in the D energy level, and A0 and A1 represent another two sub-energy levels in the D energy level.

[0080] If the steady state and the metastable state are called the excited state, the computational space (Q0 - Q1) and the auxiliary space (A0 - A1) can have the following several combination forms: (ground state - ground state) and (excited state - excited state); (ground state - ground state) and (ground state - excited state); (ground state - excited state) and (ground state - excited state); (ground state - excited state) and (excited state - excited state). The combinations mentioned here refer to the combinations of sub-energy levels in the ground state and sub-energy levels in the excited state.

[0081] Before the space transfer, the multiple ions are all in the computational space, that is, the multiple ions are in the same energy level. For example, the multiple ions are all inFigure 5 The computational spaces represented by Q0 and Q1 in the first combination method shown.

[0082] Since there are differences in the transition frequencies of the multiple ions, the energy levels of the multiple first ions are adjusted according to the transition frequencies of the multiple first ions as described above, so as to transfer the multiple first ions from the computational space to the auxiliary space. For example, the multiple first ions are adjusted from the computational spaces represented by Q0 and Q1 to the auxiliary spaces represented by A0 and A1.

[0083] In one implementation, the control device generates a first control signal according to the transition frequencies of the multiple first ions. The first control signal has multiple frequencies that match the transition frequencies of the multiple first ions, and matching means that resonance can be generated. The control device uses the first control signal to control the multiple first ions to perform energy level transitions, so as to transfer the multiple first ions from the computational space to the auxiliary space.

[0084] Among them, the first control signal includes a first laser signal and / or a first microwave signal.

[0085] In the first implementation, the first control signal is a first laser signal. The control device includes a laser, a controller, and a modulator as shown in Figure 1 The laser generates a first original laser signal and transmits the first original laser signal to the modulator. The controller generates control signals of the multiple frequencies described above and transmits the control signals of the multiple frequencies to the modulator. The modulator performs frequency modulation on the first original laser signal through the control signals of the multiple frequencies to obtain a first laser signal, and uses the first laser signal to control the multiple first ions to perform energy level transitions, so as to transfer the multiple first ions from the computational space to the auxiliary space.

[0086] Specifically, the modulator irradiates the multiple ions with the first laser signal, prompting multiple first ions among the multiple first ions to perform energy level transitions, thereby transferring the multiple first ions from the computational space to the auxiliary space. And since the first laser signal does not have frequencies that match the transition frequencies of multiple second ions among the multiple ions, the multiple second ions will not undergo energy level transitions, so the multiple second ions remain in the computational space.

[0087] In the second implementation, the first control signal is a first microwave signal. The control device includes a microwave device, a controller, and a modulator. The microwave device generates a first original microwave signal and transmits the first original microwave signal to the modulator. The controller generates control signals of the multiple frequencies described above and transmits the control signals of the multiple frequencies to the modulator. The modulator performs frequency modulation on the first original microwave signal through the control signals of the multiple frequencies to obtain a first microwave signal, and uses the first microwave signal to control the multiple first ions to perform energy level transitions, so as to transfer the multiple first ions from the computational space to the auxiliary space.

[0088] Specifically, the modulator emits a first microwave signal to the plurality of ions, prompting a plurality of the first ions among the plurality of first ions to undergo energy level transitions, thereby transferring the plurality of first ions from the computational space to the auxiliary space. Since the first microwave signal does not have a frequency matching the transition frequency of a plurality of second ions among the plurality of ions, the plurality of second ions do not undergo energy level transitions, and thus the plurality of second ions remain in the computational space.

[0089] In a third implementation manner, the first manipulation signal includes a first laser signal and a first microwave signal. The manipulation device includes a microwave device, a laser, a controller, and a modulator. The laser generates a first original laser signal and transmits the first original laser signal to the modulator. The microwave device generates a first original microwave signal and transmits the first original microwave signal to the modulator. The controller generates control signals of the above-mentioned multiple frequencies and transmits the control signals of the multiple frequencies to the modulator. The multiple frequencies include two parts, one part corresponding to the first original laser signal and the other part corresponding to the first original microwave signal. The modulator frequency-modulates the first original laser signal through a part of the control signals of the multiple frequencies to obtain a first laser signal, and frequency-modulates the first original microwave signal through the other part of the control signals of the multiple frequencies to obtain a first microwave signal, and uses the first laser signal and the first microwave signal to control the plurality of first ions to undergo energy level transitions to transfer the plurality of first ions from the computational space to the auxiliary space.

[0090] The specific implementation manner of using the first laser signal and the first microwave signal to control the plurality of first ions to undergo energy level transitions is similar to the corresponding content in the above-mentioned first and second manners, and will not be repeated here.

[0091] Optionally, in addition to the above components, the manipulation device may further include other components. For example, it may further include an input device for receiving a quantum information processing task input by a user, or it may further include an output device, a communication interface, etc. The manipulation device may be the quantum computer introduced above.

[0092] As can be seen from the above, the plurality of ions in the embodiments of the present application include a plurality of identical ions, that is, the same isotope of the same element. For example, the plurality of ions include a plurality of Ca-40 or a plurality of Yb-171 or a plurality of Ba-133.

[0093] Among them, the Ca-40 ion is an atom with a nuclear spin of 0, and there are many Zeeman energy levels inside the ground state (S) and the excited state (D). These energy levels are first-order sensitive to the external magnetic field, that is, the energy of the energy levels is directly proportional to the strength of the external magnetic field at a first order. Therefore, the transition between the ground state and the excited state of the Ca-40 ion can be selected to achieve the above-mentioned space transfer, and this transition is the so-called electric quadrupole transition.

[0094] Exemplarily, the transition of Ca-40 ions from the S energy level to the D energy level can be driven by a laser signal generated by a laser with a wavelength of 729 nm, or can be driven by a microwave signal (i.e., radio frequency signal) generated by a radio frequency antenna. The transition between the two sub-energy levels included in the S energy level can also be driven by a microwave signal (i.e., radio frequency signal) generated by a radio frequency antenna, or by a laser signal generated by a laser with other wavelengths.

[0095] As can be seen from the above, before the spatial transfer in step 401, the multiple ions are in the same energy level. For example, after initialization, the multiple ions are in the same energy level, or for another example, after a quantum manipulation, the multiple ions return to the same energy level through spatial transfer. The following is an introduction to this.

[0096] Figure 6 It is a flowchart of another quantum manipulation method provided by an embodiment of the present application. Refer to Figure 6 , after the user inputs a quantum information processing task, the following processes will occur: initialization - calibration - quantum manipulation - quantum state readout.

[0097] Among them, initialization mainly realizes the stable confinement of the multiple ions, that is, through a magnetic field, the internal state and external state of the multiple ions are initialized to a specified quantum state. For example, through a magnetic field, the multiple ions are stably confined in a straight line to form a one-dimensional ion chain, or through a magnetic field, the multiple ions are stably confined in a plane to form a neatly arranged two-dimensional ion crystal, or through a magnetic field, the multiple ions are stably confined in a local space to form a neatly arranged three-dimensional ion crystal. The specific implementation manner of initialization can refer to related technologies. After initialization, the multiple ions are in the same energy level.

[0098] Calibration mainly calibrates the transition frequency and rate of each ion. Since the magnetic field magnitude at the position where each ion is located is different, the transition frequencies of each ion are different. For an ion trap system including M ions, the number of transition frequencies to be calibrated is k*M, where k is the maximum number of transitions that may be used inside a single ion, and k is usually equal to the number of sub-energy levels included in the multi-energy level minus 1. Here, the rate refers to the intensity of the interaction between the ion and the laser, that is, the Rabi rate, and the difference in the rate between different ions is due to the different laser intensities felt by different ions. The calibration of multiple ions can be carried out in parallel or separately, which can be determined according to the actual situation. During the calibration process, the ions may undergo energy level transitions, and after calibration, the multiple ions return to the same energy level.

[0099] Quantum manipulation includes single-bit (bit) gate manipulation (i.e., 1-bit gate manipulation) and multi-bit gate manipulation.

[0100] Among them, the 1-bit gate manipulation uses the means of frequency resonance to modulate the frequency of the global laser or microwave to the frequency resonant with the transition frequency of the single ion to be manipulated. Through this laser or microwave, a 1-bit manipulation quantum logic operation is performed on the single ion, thereby forming a single qubit. The specific implementation method of the 1-bit gate manipulation can refer to the related technology, and the embodiments of the present application will not be introduced in detail. It should be noted that the 1-bit gate manipulation does not require spatial transfer. Even if all ions are in the computing space during the manipulation process, the high fidelity of ion manipulation can be guaranteed. Of course, in other possible implementation methods, the 1-bit gate manipulation can also perform spatial transfer, that is, transfer the ions other than the above single ion to the auxiliary space first, then perform a 1-bit manipulation quantum logic operation on this single ion, and then transfer the ions in the auxiliary space back to the computing space after the operation.

[0101] It is generally considered that the realization of 1-bit gate manipulation and 2-bit gate manipulation can achieve quantum manipulation of any number of bits. This article mainly describes the improvement of 2-bit gate manipulation.

[0102] The 2-bit gate manipulation includes the above-mentioned spatial transfer and the quantum manipulation in step 402. This is the key process of this solution. Specifically, a spatial transfer is first performed to transfer multiple first ions to the auxiliary space, then a two-bit quantum manipulation is performed on multiple second ions in the computing space, and after the manipulation, the multiple first ions are converted back to the computing space, so that these multiple ions return to the same energy level.

[0103] Figure 7 It is a schematic diagram of an ion manipulation provided by the embodiments of the present application. Figure 7 In [the figure], K1 to K5 represent 5 ions. When performing 1-bit gate manipulation (represented by the symbol R in the figure) on the ion represented by K1, no spatial transfer is required for other ions. When performing 2-bit gate manipulation on the two ions represented by K3 and K5, it is necessary to first transfer the 3 ions represented by K1, K2, and K4 to the auxiliary space, then perform 2-bit gate manipulation on the two ions represented by K3 and K5, and then transfer the 3 ions represented by K1, K2, and K4 back to the computing space.

[0104] Quantum state readout is to confirm which specific quantum state the ion is in by collecting the fluorescence emitted by the ion. In the embodiments of the present application, a detector with spatial discrimination is used to read out the quantum state of the ion, and the detector can be implemented by a camera (such as an electron multiplying charge coupled device (EMCCD)) or a multi-channel photomultiplier tube (PMT) or other devices.

[0105] Next, a more detailed introduction to multi-bit quantum manipulation is given through step 402.

[0106] Step 402: Perform quantum manipulation on multiple second ions in the computational space to form multiple qubits, where the multiple second ions are the ions among the multiple ions other than the multiple first ions.

[0107] Since this solution does not require optical ion finding, multi-bit quantum manipulation can be achieved by using global laser and / or global microwave to perform quantum manipulation on the multiple second ions.

[0108] The global laser is generated by the laser introduced above, and the global microwave is generated by the RF antenna introduced above.

[0109] Taking the use of global laser to perform quantum manipulation on the multiple second ions as an example, the laser generates a second original laser signal and transmits the second original laser signal to the modulator. The modulator modulates the second original laser signal in terms of amplitude, phase or frequency under the control of the controller to obtain a second manipulation signal, and uses the second manipulation signal to perform quantum manipulation on the multiple second ions in the computational space. The second manipulation signal is a global laser signal.

[0110] Next, a detailed introduction to 2-bit gate manipulation is given.

[0111] The number of the above-mentioned multiple second ions is 2, and the quantum manipulation in step 402 includes a quantum entanglement operation. Specifically, the implementation process of performing quantum manipulation on the multiple second ions in the computational space includes: performing a quantum entanglement operation on the multiple second ions at a first angle, where the first angle is a times the angle required for two-bit entanglement, and a is greater than 0 and less than 1; performing single-bit flip operations on the multiple second ions after the quantum entanglement operation respectively; performing a quantum entanglement operation on the multiple second ions after the single-bit flip operation again at a second angle, where the sum of the second angle and the first angle is equal to the angle required for two-bit entanglement. Briefly speaking, first perform a part of the quantum entanglement operation on these two second ions, then perform a single-bit flip operation on these two second ions respectively, and then perform another part of the quantum entanglement operation on these two second ions.

[0112] In the embodiment of the present application, the above-mentioned a is 0.5. That is, the angles of the above-mentioned two quantum entanglement operations are both θ / 2, which is easy to implement and also convenient for theoretically calculating the influence brought by these two quantum entanglement operations. Here, θ represents the angle required for two-bit entanglement.

[0113] Certainly, in other embodiments, a can also be other values, such as 1 / 3 or 1 / 4, etc.

[0114] It can be seen that the 2-bit gate manipulation in this solution includes 2-bit quantum entanglement operation + 1-bit flip operation + 2-bit quantum entanglement operation, while the 2-bit gate manipulation in the related technology includes one 2-bit quantum entanglement operation. Next, the reasons for doing so in this solution will be explained.

[0115] Here, taking the MS logic gate as an example, the specific implementation method of 2-bit quantum manipulation is analyzed. Since there is a frequency difference between the two second ions, the evolution operator generated under the action of the global laser or global microwave will be different from the ideal situation.

[0116] Taking the global laser as an example, for two ions with different transition frequencies, under the irradiation of the global laser, the Hamiltonian of the system can be expressed as expression (1).

[0117]

[0118] In expression (1), σ x and σ z represent the Pauli operators for single-bit manipulation, i represents the ion number, λ represents the energy difference caused by the frequency difference between the two ions, η represents the coupling strength between the ion and the vibration mode, a and respectively represent the annihilation and creation operators on the vibration mode, ∈ represents the difference between the global laser and the ion frequency, Ω(t) represents the intensity of the global laser, and here the intensity varies with time t. The global laser can be the Figure 8 smooth pulse shown.

[0119] Under the action of the Hamiltonian of the above system, after these two ions are irradiated by the global laser for a time t, the quantum operation operator can be expressed as expression (2).

[0120] U(t) = exp{H I + H N} (2)

[0121] In expression (2), H I represents the ideal part of the quantum logic manipulation, and H N represents the difference part introduced due to the frequency difference. H I and H N are respectively expressed as expression (3) and expression (4).

[0122]

[0123]

[0124] In expressions (3) and (4), both β(t) and κ(t) are related to the waveform of the global laser. During the operation, by selecting appropriate laser parameters, both β(t) and κ(t) can be made equal to 0. The specific implementation can refer to the related technology. i and j represent the ion numbers, and θ(t1, t2) represents the angle required for two-bit entanglement. H N The remaining This error term can be eliminated during the operation in a way similar to spin-echo. The specific implementation method is the 2-bit quantum entanglement operation + 1-bit flip operation + 2-bit quantum entanglement operation in this solution.

[0125] Figure 9 is a schematic diagram of 2-bit quantum manipulation in an embodiment of this application. See Figure 9 For the two ions represented by K3 and K5, first perform an MS logic gate operation according to the angle θ / 2, then perform a single-bit flip operation on each of these two ions (represented by the symbol π in the figure), and then perform an MS logic gate operation according to the angle θ / 2, so as to complete the two-bit quantum manipulation of these two ions. The middle single-bit flip operation combined with the two MS logic gate operations before and after can eliminate the remaining N in H this error term.

[0126] The implementation process of 2-bit quantum manipulation is introduced above. The idea of the above-mentioned spatial transfer combined with error elimination can also be extended to quantum manipulation of more bits, that is, the number of the above-mentioned multiple second ions can also be greater than 2, which will not be elaborated here one by one. It is worth emphasizing again that usually, combining 1-bit quantum manipulation and 2-bit quantum manipulation can achieve quantum manipulation of any number of bits. Therefore, in practical applications, any possible quantum information processing task can be completed by performing 1-bit quantum manipulation and 2-bit quantum manipulation.

[0127] After performing quantum manipulation on the above-mentioned multiple second ions to form multiple qubits, in order to perform the next quantum manipulation, it is also necessary to transfer the above-mentioned multiple first ions back to the computational space. That is, according to the transition frequencies of the multiple first ions, adjust the energy levels of the multiple first ions to transfer the multiple first ions from the auxiliary space back to the computational space. The specific implementation method is similar to step 401, the difference is that if in step 401, a certain first ion transitions from a low energy level to a high energy level, then here this first ion transitions from a high energy level to a low energy level, that is, the energy level transition here is opposite to the energy level transition in step 401.

[0128] Exemplarily, transfer the ions in the auxiliary space corresponding to A0 and A1 to the computational space corresponding to Q0 and Q1 through global laser or global microwave.

[0129] It should be noted that, since this solution uses the multi-level structure of ions and the difference in transition frequencies between ions for spatial transfer, multiple second ions and multiple first ions are in different energy levels. Therefore, quantum manipulation can be achieved without a strong magnetic field gradient. For example, compared with the magnetic field gradient of about 100 T / m required in related technologies, this solution can achieve quantum manipulation with a magnetic field gradient less than 100 T / m. For example, a magnetic field gradient of 0.04 T / m used in medical applications can be used, or a more conventional magnetic field gradient of 0.01 T / m can be used.

[0130] Taking a magnetic field gradient of 0.01 T / m as an example, assuming that the distance between adjacent ions is on the order of 10 micrometers (μm), then the difference in transition frequencies between ions where μ represents the Bohr magneton, represents the magnetic field gradient, and Δz represents the distance between adjacent ions.

[0131] At a frequency resolution of 10 kHz, for 1-bit quantum manipulation, a laser pulse of about 100 μs, such as a 100 μs square wave, can be used to achieve crosstalk-free manipulation. To further reduce crosstalk, the square wave can be replaced with a smooth pulse with rising and falling edges as shown in Figure 8 .

[0132] This solution can be applied to the manipulation of one-dimensional ion chains or two-dimensional ion crystals. The feasibility of applying this solution to the manipulation of two-dimensional ion crystals will be introduced below.

[0133] The two-dimensional ion crystal is confined in a limited space by a magnetic field. There are magnetic field gradients in both dimensions of the two-dimensional ion crystal. As shown in Figure 10 , there are magnetic field gradients in the x and y directions of the magnetic field, which are respectively represented as G x and G y . Considering using the energy levels in the ions that are first-order sensitive to the magnetic field as qubits, the frequencies of the internal energy levels of each ion need to be different. The magnitude of the magnetic field felt by the ion at coordinates (x, y) is expressed as Expression (5).

[0134]

[0135] In Equation (5), B0 represents the basic bias magnetic field, which is used to define the quantization axis of the ions.

[0136] Then, the transition frequency of the ion at coordinates (x, y) can be expressed as Expression (6).

[0137]

[0138] As can be seen from Equation (6), there are differences in the transition frequencies of ions at different positions, and this difference can be demonstrated by Figure 11 the spectral lines shown.

[0139] Through the above analysis, it is found that applying a magnetic field with a magnetic field gradient in a two-dimensional ion crystal can make the transition frequencies of multiple ions in the two-dimensional ion crystal different. Then, this solution can be applied to the two-dimensional ion crystal.

[0140] Similarly, this solution can also be extended to three-dimensional ion crystals. That is, applying a magnetic field with a magnetic field gradient in a three-dimensional ion crystal makes the transition frequencies of multiple ions in the three-dimensional ion crystal different, and then using this frequency difference and the multi-level structure of the ions, quantum manipulation of specified ions is achieved through spatial transfer.

[0141] The core idea of this solution can also be applied to other hardware systems outside the ion trap system, such as atomic systems, diamond systems, nuclear magnetic systems, etc. This core idea is to use a magnetic field gradient to make the frequencies of multiple objects in the system different, and then use the frequency difference between the objects and the multi-level structure inside the objects to achieve manipulation of specified objects through spatial transfer.

[0142] In summary, in the embodiments of this application, by adjusting the energy levels of the ions, the ions irrelevant to quantum manipulation are transferred to the auxiliary space, and quantum manipulation is performed on the ions in the computational space. It can be seen that this solution does not require the ions to find light, that is, it does not require complex chip processing means. This solution also does not require light to find ions, that is, it does not require the technology of strong laser focusing, and has a low requirement for the pointing stability of the laser. This solution can achieve multi-ion manipulation using global laser or microwave, is easy to implement, and can ensure the system stability without strong laser focusing. And due to the spatial transfer, this solution can achieve multi-ion manipulation using a smaller magnetic field gradient, greatly reducing the threshold of ion manipulation and providing a new idea for quantum information processing.

[0143] Figure 12 FIG. is a schematic structural diagram of an ion manipulation device provided by an embodiment of this application. This ion manipulation device can be implemented by software, hardware, or a combination of both to become part or all of the manipulation device, and this manipulation device can be the manipulation device introduced in the above embodiments. In the embodiments of this application, this ion manipulation device is applied to an ion trap system. This ion trap system includes multiple ions, and these multiple ions are in a magnetic field with a magnetic field gradient, and this magnetic field gradient makes the transition frequencies of these multiple ions different, and each ion in these multiple ions has a multi-level structure. Refer to Figure 12 , this device includes: a spatial transfer module 1201 and a quantum manipulation module 1202.

[0144] A space transfer module 1201, configured to adjust energy levels of the plurality of first ions according to transition frequencies of the plurality of first ions, so as to transfer the plurality of first ions from a calculation space to an auxiliary space, where the plurality of ions includes the plurality of first ions, and energy levels of ions in the calculation space are different from those of ions in the auxiliary space;

[0145] A quantum manipulation module 1202, configured to perform quantum manipulation on a plurality of second ions in the calculation space to form a plurality of qubits, where the plurality of second ions are ions other than the plurality of first ions among the plurality of ions.

[0146] Optionally, the quantum manipulation module 1202 is specifically configured to:

[0147] Perform quantum manipulation on the plurality of second ions by using a global laser and / or a global microwave.

[0148] Optionally, the space transfer module 1201 is specifically configured to:

[0149] Generate a first manipulation signal according to the transition frequencies of the plurality of first ions, where the first manipulation signal has a plurality of frequencies matching the transition frequencies of the plurality of first ions;

[0150] Control the plurality of first ions to perform energy level transitions by using the first manipulation signal, so as to transfer the plurality of first ions from the calculation space to the auxiliary space.

[0151] Optionally, the first manipulation signal includes a first laser signal and / or a first microwave signal.

[0152] Optionally, the number of the plurality of second ions is 2, and the quantum manipulation includes a quantum entanglement operation;

[0153] The quantum manipulation module 1202 is specifically configured to:

[0154] Perform a quantum entanglement operation on the plurality of second ions at a first angle, where the first angle is a times an angle required for two-qubit entanglement, and a is greater than 0 and less than 1;

[0155] Perform single-bit flip operations on the plurality of second ions after the quantum entanglement operation respectively;

[0156] Perform a quantum entanglement operation on the plurality of second ions after the single-bit flip operation again at a second angle, where the sum of the second angle and the first angle is equal to the angle required for two-qubit entanglement.

[0157] Optionally, a is 0.5.

[0158] Optionally, the space transfer module 1201 is further configured to:

[0159] After quantum-manipulating a plurality of second ions in a computational space to form a plurality of qubits, the energy levels of the plurality of first ions are adjusted according to the transition frequencies of the plurality of first ions, so as to transfer the plurality of first ions from an auxiliary space back to the computational space.

[0160] Optionally, the above-mentioned multi-level energy levels include at least four sub-levels. The computational space corresponds to two first sub-levels among the at least four sub-levels, and the auxiliary space corresponds to two second sub-levels among the at least four sub-levels. These two first sub-levels are any two sub-levels among the at least four sub-levels, and these two second sub-levels are any two sub-levels among the at least four sub-levels other than these two first sub-levels.

[0161] Optionally, the above-mentioned multi-level energy levels include a ground state energy level, a steady state energy level, and a metastable state energy level. Any one of the at least four sub-levels is a sub-level in the ground state energy level or a sub-level in the steady state energy level or a sub-level in the metastable state energy level.

[0162] Optionally, the above-mentioned plurality of ions include a plurality of identical ions.

[0163] In the embodiments of the present application, by adjusting the energy levels of the ions, the ions irrelevant to quantum manipulation are transferred to the auxiliary space, and the ions in the computational space are quantum-manipulated. It can be seen that this solution does not require the ions to find light, that is, no complex chip processing means are required. This solution also does not require light to find ions, that is, no laser strong focusing technology is required, and the requirement for the pointing stability of the laser is relatively low. This solution can achieve multi-ion manipulation by using global laser or microwave, which is easy to implement, and the system stability can be ensured without laser strong focusing. And due to the space transfer, this solution can achieve multi-ion manipulation by using a smaller magnetic field gradient, greatly reducing the threshold of ion manipulation and providing a new idea for quantum information processing.

[0164] It should be noted that when the above-mentioned ion manipulation device manipulates ions, only the division of the above-mentioned functional modules is used for illustration. In practical applications, the above-mentioned functions can be allocated to different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. In addition, the above-mentioned ion manipulation device provided in the embodiments and the embodiments of the ion manipulation method belong to the same concept, and the specific implementation process can be seen in the method embodiments, which will not be elaborated here.

[0165] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another. For example, the computer instructions may be transmitted from a website, computer, server, or data center to another website, computer, server, or data center in a wired manner (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or a wireless manner (such as infrared, wireless, microwave, etc.). The computer-readable storage medium may be any available medium that can be accessed by a computer, or a data storage device such as a server or data center that includes one or more integrated available media. The available medium may be a magnetic medium (such as a floppy disk, hard disk, magnetic tape), an optical medium (such as a digital versatile disc (DVD)), or a semiconductor medium (such as a solid state disk (SSD)), etc. It should be noted that the computer-readable storage medium mentioned in the embodiments of the present application may be a non-volatile storage medium, in other words, a non-transitory storage medium.

[0166] It should be understood that the "at least one" mentioned herein refers to one or more, and "a plurality" refers to two or more. In the description of the embodiments of the present application, unless otherwise specified, " / " means "or". For example, A / B may mean A or B; the "and / or" herein is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in order to clearly describe the technical solutions of the embodiments of the present application, in the embodiments of the present application, terms such as "first" and "second" are used to distinguish the same items or similar items with basically the same functions and effects. Those skilled in the art can understand that the terms "first", "second", etc. do not limit the quantity and execution order, and the terms "first", "second", etc. do not necessarily mean different.

[0167] It should be noted that the information (including but not limited to user device information, user personal information, etc.), data (including but not limited to data for analysis, stored data, displayed data, etc.), and signals involved in the embodiments of this application are all authorized by the user or fully authorized by all parties, and the collection, use, and processing of relevant data need to comply with the relevant laws, regulations, and standards of relevant countries and regions.

[0168] The above are the embodiments provided by this application, which are not intended to limit this application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of this application shall be included within the protection scope of this application.

Claims

1. An ion manipulation method, characterized in that, Applied to an ion trap system, the ion trap system includes a plurality of ions, the plurality of ions being in a magnetic field with a magnetic field gradient, the magnetic field gradient causing the transition frequencies of the plurality of ions to be different, and each ion in the plurality of ions having a multi-level structure; the method includes: Adjust the energy levels of the plurality of first ions according to the transition frequencies of the plurality of first ions to transfer the plurality of first ions from the computational space to the auxiliary space, the plurality of ions including the plurality of first ions, and the ions in the computational space being at different energy levels from the ions in the auxiliary space; Perform quantum manipulation on a plurality of second ions in the computational space to form a plurality of qubits, the plurality of second ions being the ions among the plurality of ions other than the plurality of first ions.

2. The method according to claim 1, characterized in that, The performing quantum manipulation on the plurality of second ions in the computational space includes: Performing quantum manipulation on the plurality of second ions using a global laser and / or a global microwave.

3. The method according to claim 1 or 2, characterized in that, The adjusting the energy levels of the plurality of first ions according to the transition frequencies of the plurality of first ions to transfer the plurality of first ions from the computational space to the auxiliary space includes: Generating a first manipulation signal according to the transition frequencies of the plurality of first ions, the first manipulation signal having a plurality of frequencies matching the transition frequencies of the plurality of first ions; Using the first manipulation signal to control the plurality of first ions to perform energy level transitions to transfer the plurality of first ions from the computational space to the auxiliary space.

4. The method according to claim 3, characterized in that, The first manipulation signal includes a first laser signal and / or a first microwave signal.

5. The method according to any one of claims 1-4, characterized in that, The number of the plurality of second ions is 2, and the quantum manipulation includes a quantum entanglement operation; The performing quantum manipulation on the plurality of second ions in the computational space includes: Performing a quantum entanglement operation on the plurality of second ions at a first angle, the first angle being a times the angle required for two-bit entanglement, where a is greater than 0 and less than 1; Performing single-bit flip operations on the plurality of second ions after the quantum entanglement operation respectively; Performing a quantum entanglement operation on the plurality of second ions after the single-bit flip operation again at a second angle, the sum of the second angle and the first angle being equal to the angle required for two-bit entanglement.

6. The method according to claim 5, characterized in that, The a is 0.

5.

7. The method according to any one of claims 1-6, characterized in that, After the performing quantum manipulation on the plurality of second ions in the computational space to form a plurality of qubits, the method further includes: Adjust the energy levels of the plurality of first ions according to the transition frequencies of the plurality of first ions to transfer the plurality of first ions from the auxiliary space back to the computational space.

8. The method according to any one of claims 1 to 7, characterized in that, The multi-level includes at least four sub-levels, the computational space corresponding to two first sub-levels among the at least four sub-levels, the auxiliary space corresponding to two second sub-levels among the at least four sub-levels, the two first sub-levels being any two sub-levels among the at least four sub-levels, and the two second sub-levels being any two sub-levels among the at least four sub-levels other than the two first sub-levels.

9. The method according to claim 8, wherein The multi-level energy levels include a ground state energy level, a steady state energy level, and a metastable state energy level, and any one of the at least four sub-energy levels is a sub-energy level in the ground state energy level or a sub-energy level in the steady state energy level or a sub-energy level in the metastable state energy level.

10. The method according to any one of claims 1-9, characterized in that, The multiple ions include multiple identical ions.

11. An ion manipulation device, characterized in that, Applied to an ion trap system, the ion trap system includes multiple ions, the multiple ions are in a magnetic field with a magnetic field gradient, the magnetic field gradient causes the transition frequencies of the multiple ions to be different, and each ion in the multiple ions has a multi-level energy level structure; the apparatus includes: A spatial transfer module, configured to adjust the energy levels of the multiple first ions according to the transition frequencies of the multiple first ions, so as to transfer the multiple first ions from a calculation space to an auxiliary space, the multiple ions include the multiple first ions, and the energy levels of the ions in the calculation space are different from those of the ions in the auxiliary space; A quantum manipulation module, configured to perform quantum manipulation on multiple second ions in the calculation space to form multiple qubits, the multiple second ions are the ions other than the multiple first ions among the multiple ions.

12. The device according to claim 11, characterized in that, The quantum manipulation module is specifically configured to: Perform quantum manipulation on the multiple second ions by using a global laser and / or a global microwave.

13. The device according to claim 11 or 12, characterized in that, The spatial transfer module is specifically configured to: Generate a first manipulation signal according to the transition frequencies of the multiple first ions, the first manipulation signal having multiple frequencies matching the transition frequencies of the multiple first ions; Use the first manipulation signal to control the multiple first ions to perform energy level transitions, so as to transfer the multiple first ions from the calculation space to the auxiliary space.

14. The device according to claim 13, wherein The first manipulation signal includes a first laser signal and / or a first microwave signal.

15. The device according to any one of claims 11-14, characterized in that, The number of the multiple second ions is 2, and the quantum manipulation includes a quantum entanglement operation; The quantum manipulation module is specifically configured to: Perform a quantum entanglement operation on the multiple second ions according to a first angle, the first angle being a times the angle required for two-qubit entanglement, where a is greater than 0 and less than 1; Perform single-bit flip operations on the multiple second ions after the quantum entanglement operation respectively; Perform a quantum entanglement operation on the multiple second ions after the single-bit flip operation again according to a second angle, the sum of the second angle and the first angle being equal to the angle required for two-qubit entanglement.

16. The device according to claim 15, wherein The a is 0.

5.

17. The device according to any one of claims 11-16, characterized in that, The spatial transfer module is further configured to: After performing quantum manipulation on multiple second ions in the calculation space to form multiple qubits, adjust the energy levels of the multiple first ions according to the transition frequencies of the multiple first ions, so as to transfer the multiple first ions from the auxiliary space back to the calculation space.

18. The device according to any one of claims 11-17, characterized in that The multi-level includes at least four sub-levels. The calculation space corresponds to two first sub-levels among the at least four sub-levels, and the auxiliary space corresponds to two second sub-levels among the at least four sub-levels. The two first sub-levels are any two sub-levels among the at least four sub-levels, and the two second sub-levels are any two sub-levels among the at least four sub-levels other than the two first sub-levels.

19. The device according to claim 18, characterized in that, The multi-level includes a ground state level, a steady state level, and a metastable state level. Any one of the at least four sub-levels is a sub-level in the ground state level or a sub-level in the steady state level or a sub-level in the metastable state level.

20. The device according to any one of claims 11-19, characterized in that, The plurality of ions includes a plurality of identical ions.

21. An ion trap system, characterized in that, The ion trap system includes a plurality of ions. The plurality of ions are in a magnetic field with a magnetic field gradient, and the magnetic field gradient causes the transition frequencies of the plurality of ions to be different. Each ion in the plurality of ions has a multi-level structure. The ion trap system is used to implement the method according to any one of claims 1-10.

22. A computer-readable storage medium, characterized in that, The storage medium stores a computer program, and when the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1-10.

23. A computer program product, characterized in that, The computer program product stores computer instructions, and when the computer instructions are executed by a processor, it implements the steps of the method according to any one of claims 1-10.

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