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

Abstract

The present application belongs to the technical field of quantum information. Disclosed are an ion control method and apparatus, an ion trap system, and a related apparatus. A plurality of ions in the ion trap system are located in a magnetic field having a magnetic field gradient, wherein the magnetic field gradient causes a difference in the transition frequencies of the plurality of ions, and each ion has a multi-energy-level structure. The method comprises: according to the transition frequencies of a plurality of first ions, adjusting an energy level at which the first ions are located, so as to transfer first ions, which are irrelevant to quantum control, from a computational space to an auxiliary space, wherein ions in the computational space are located at a different energy level from ions in the auxiliary space; and performing quantum control on a plurality of second ions in the computational space, so as to form a plurality of quantum bits. The solution neither requires ion-photon coupling, nor requires optical ion addressing, can realize multi-ion control by using a global laser or microwaves, and is easy to implement. Moreover, multi-ion control can be realized by using a small magnetic field gradient, thereby reducing the threshold for ion control.

Description

Ion manipulation method, device, ion trap system and related devices

[0001] This application claims priority to the Chinese patent application with application number 202311866643.X filed on December 29, 2023, and invention name “Ion manipulation method, device, ion trap system and related device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of quantum information technology, and in particular to an ion manipulation method, device, ion trap system and related devices. Background Art

[0003] Quantum information technology has become a key research area in the development of information technology. It is widely used in fields such as quantum computing, quantum simulation, quantum sensing, and precision measurement. A key aspect of quantum information technology lies in quantum manipulation. This manipulation relies on ion trap systems, which confine ions within a limited space and utilize specific electromagnetic fields to constrain their movement. This allows the manipulation of the ions to form information-carrying quantum bits.

[0004] Related technologies provide two methods for manipulating ions. The first method is based on ion transport technology, which is ion-seeking light. In this method, a multi-electrode chip structure is produced by micro-nano processing means, and a time-varying voltage signal is applied to the multi-electrodes. The voltage signal is used to realize the movement of ions in space, and the ions are transported to the specified control light range, thereby realizing the logical manipulation of the ions. The second method is based on the spatial focusing technology of the laser, that is, the technology of light-seeking ions. In this method, the laser is focused to a diameter smaller than the ion spacing by optical means. When performing quantum operations, the laser on the specific ion is turned on within a specific time period to achieve logical manipulation of the specific ion.

[0005] However, the first method requires very complex micro-nanofabrication technology and complicated chip processing. The second method also places high demands on the diffraction limit of laser focusing and the stability of laser pointing, making it difficult to implement and resulting in poor system stability. Summary of the Invention

[0006] This application provides an ion manipulation method, device, ion trap system, and related devices that do not require complex chip processing methods or strong laser focusing technology, have low requirements for laser pointing stability, are easy to implement, and lower the threshold for ion manipulation. The technical solution is as follows:

[0007] In a first aspect, an ion manipulation method is provided, which is applied to an ion trap system, wherein the ion trap system includes a plurality of ions, the plurality of ions being in a magnetic field having a magnetic field gradient, the magnetic field gradient causing differences in transition frequencies of the plurality of ions, and each of the plurality of ions having a multi-energy-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 to transfer the plurality of first ions from a computational space to an auxiliary space, the plurality of ions including the plurality of first ions, the ions in the computational space being at different energy levels from the ions in the auxiliary space; and performing quantum manipulation on a plurality of second ions in the computational space to form a plurality of quantum bits, the plurality of second ions being ions in the plurality of ions other than the plurality of first ions.

[0008] This scheme performs quantum manipulation on ions in the computational space by adjusting their energy levels and transferring ions irrelevant to quantum manipulation into an auxiliary space. This approach eliminates the need for ion-finding light, which means complex chip processing techniques are unnecessary. It also eliminates the need for light-finding ions, which means strong laser focusing techniques are not required, and the requirements for laser pointing stability are relatively low. Furthermore, due to the spatial transfer, this scheme can achieve multi-ion manipulation with relatively small magnetic field gradients, significantly lowering the threshold for ion manipulation and increasing the number of manipulated ions while maintaining high fidelity, providing new insights into quantum information processing.

[0009] The quantum manipulation of multiple second ions in the computational space includes quantum manipulation of the multiple second ions using global lasers and / or global microwaves. This solution utilizes global lasers or microwaves to achieve multi-ion manipulation, is easy to implement, and can maintain system stability without requiring strong laser focusing.

[0010] Among them, according to the transition frequencies of the multiple first ions, the energy levels of the multiple first ions are adjusted to transfer the multiple first ions from the calculation space to the auxiliary space, including: generating 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; using the first manipulation signal to control the energy level transition of the multiple first ions to transfer the multiple first ions from the calculation space to the auxiliary space.

[0011] The first control signal includes a first laser signal and / or a first microwave signal.

[0012] In one possible implementation, the number of the multiple second ions is two, and the quantum manipulation includes a quantum entanglement operation. The quantum manipulation of 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, where a is greater than 0 and less than 1; performing a single-bit flip operation on each of the multiple second ions after the quantum entanglement operation; and performing a further quantum entanglement operation on the multiple second ions after the single-bit flip operation at a second angle, where the sum of the second angle and the first angle equals the angle required for two-bit entanglement. In other words, this solution eliminates errors caused by differences in ion transition frequencies by combining the two two-bit quantum entanglement operations with the intermediate single-bit flip operation.

[0013] In one possible implementation, a is 0.5.

[0014] After performing quantum manipulation on the plurality of second ions in the computation space to form a plurality of qubits, the method further includes adjusting the energy levels of the plurality of first ions according to their transition frequencies, thereby transferring the plurality of first ions from the auxiliary space back to the computation space. In other words, after each quantum manipulation via spatial transfer, the ions transferred to the auxiliary space need to be transferred back to facilitate the next quantum manipulation.

[0015] In one possible implementation, the above-mentioned multi-energy level includes at least four sub-energy levels, the calculation 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, 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 except the two first sub-energy levels.

[0016] In one possible implementation, the above-mentioned multiple energy levels include a ground state energy level, a stable 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, a sub-energy level in the stable state energy level, or a sub-energy level in the metastable energy level.

[0017] Wherein, the above-mentioned multiple ions include multiple identical ions.

[0018] In a second aspect, an ion manipulation device is provided, wherein the ion manipulation device has the function of implementing the ion manipulation method of the first aspect. The ion manipulation device includes one or more modules, wherein the one or more modules are used to implement the ion manipulation method of the first aspect.

[0019] In a third aspect, an ion trap system is provided, which includes a plurality of ions, wherein the plurality of ions are in a magnetic field having a magnetic field gradient, wherein the magnetic field gradient causes differences in transition frequencies of the plurality of ions, and each of the plurality of ions has a multi-energy level structure; the ion trap system is used to implement the ion manipulation method provided in the first aspect above.

[0020] In a fourth aspect, a manipulation device is provided, comprising a processor and a memory, wherein the memory is configured to store a program for executing the ion manipulation method provided in the first aspect, as well as data used to implement the ion manipulation method provided in the first aspect. The processor is configured to execute the program stored in the memory. The manipulation device may further include a communication bus for establishing a connection between the processor and the memory.

[0021] In a fifth aspect, a computer-readable storage medium is provided, wherein instructions are stored in the computer-readable storage medium, which, when executed on a computer, enables the computer to execute the ion manipulation method described in the first aspect.

[0022] In a sixth aspect, a computer program product comprising instructions is provided, which, when executed on a computer, enables the computer to execute the ion manipulation method described in the first aspect.

[0023] The technical effects obtained in the above-mentioned second to sixth aspects are similar to the technical effects obtained by the corresponding technical means in the first aspect, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG1 is a system architecture diagram of an ion manipulation method provided in an embodiment of the present application;

[0025] FIG2 is a system architecture diagram of another ion manipulation method provided in an embodiment of the present application;

[0026] FIG3 is a schematic structural diagram of an electronic device provided in an embodiment of the present application;

[0027] FIG4 is a flow chart of an ion manipulation method provided in an embodiment of the present application;

[0028] FIG5 is a schematic diagram of a combination of a computing space and an auxiliary space provided in an embodiment of the present application;

[0029] FIG6 is a flow chart of another quantum manipulation method provided in an embodiment of the present application;

[0030] FIG7 is a schematic diagram of ion manipulation provided in an embodiment of the present application;

[0031] FIG8 is a schematic diagram of a global laser provided in an embodiment of the present application;

[0032] FIG9 is a schematic diagram of a 2-bit quantum manipulation provided by an embodiment of the present application;

[0033] FIG10 is a schematic diagram of a two-dimensional ionic crystal provided in an embodiment of the present application in a magnetic field having a magnetic field gradient;

[0034] FIG11 is a diagram showing the difference in transition frequencies of multiple ions in a two-dimensional ionic crystal provided in an embodiment of the present application;

[0035] FIG12 is a schematic structural diagram of an ion manipulation device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0036] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0037] To facilitate understanding, some terms involved in the embodiments of this application are first explained.

[0038] Multi-level structure of ions: An ion's multi-level structure means that the electrons in the ion are distributed across multiple energy levels, each with a specific energy and electron distribution. The multi-level structure of an ion includes the ground state, excited state, and metastable state. The ground state refers to the lowest energy state of the ion's electrons, the excited state refers to a higher energy state, and the metastable state refers to a state between the ground and excited states. The energy level structure of an ion includes multiple energy levels, each of which can have multiple sub-energy levels. The energy level state of an ion can transition between multiple sub-energy levels, as well as between multiple energy levels. An energy level transition refers to the transition of an electron from one energy level to another, accompanied by the absorption or release of energy.

[0039] Zeeman state: refers to the energy level formed inside the ion due to angular momentum coupling. The formation of the energy level is due to the energy level splitting caused by the external magnetic field. The energy of the energy level will change with the change of the external magnetic field (generally first-order sensitive).

[0040] A geometric-phase gate (GPG) is a scheme in which two or more ions in an ion trap system are entangled using the Coulombic interaction between them to generate a resonant oscillator, thereby achieving multi-bit entanglement. There are two common implementations: the Molmer-Sorensen gate (MS) and the light-shift gate (LS). Both schemes have demonstrated very high fidelity in practical use and are currently the mainstream in the industry.

[0041] Identical ions: that is, identical isotopes of the same element. The ion trap system includes multiple identical ions, such as multiple Ca-40, multiple Yb-171, and multiple Ba-133.

[0042] Next, the relevant background of the embodiments of the present application is introduced.

[0043] Quantum computing, benefiting from the properties of quantum superposition and entanglement, shows tremendous potential for increasing computing power (providing the ability to perform parallel computations) and is a hot area of ​​cutting-edge research. As a popular candidate platform for universal quantum computers, ion trap systems still face many technical challenges and difficulties, requiring ongoing research and exploration to achieve the commercial application of quantum computing. To improve the performance of quantum systems, we focus our efforts on increasing the number of qubits and the quality of quantum manipulation. Regarding the number of qubits, we generally encode the two energy levels within a single ion as a qubit. Therefore, the number of ions that can be manipulated corresponds linearly to the number of qubits. Regarding the quality of quantum manipulation, ion trap systems primarily use laser-assisted methods to achieve coupling between qubits, but this method is subject to relatively large errors and instabilities.

[0044] This challenge requires balancing the number of qubits and the quality of quantum manipulation. This requires a processor capable of loading a large number of ions and achieving high-fidelity manipulation of these ions on a large scale by adjusting the manipulation field. To date, the number of ions that can be loaded within a single processor exceeds 1,000, while the number of ions that can be independently manipulated is approximately 30. Therefore, developing efficient schemes for independently manipulating multiple ions within a single processor has become a hot topic of research.

[0045] The ion-finding light technology provided in the related art requires very complex micro-nano processing technology and complicated chip processing technology. The light-finding ion technology has very high requirements on the diffraction limit of laser focusing and the pointing stability of the laser. It is difficult to implement and the system stability is poor.

[0046] In addition to the two approaches of ion-finding light and light-finding ion, currently, independent manipulation of ions can also be achieved through frequency addressing. In the frequency addressing approach, an external gradient control field (generally a magnetic field with a specific magnetic field gradient) is used to make originally identical ions exhibit large frequency differences in space. Then, by applying a global laser or global microwave, the ions are independently addressed through frequency differentiation. Generally, a large magnetic field gradient is required to achieve significant spatial frequency differences among multiple ions in an ion trap system. For example, a magnetic field gradient of approximately 100 Tesla per meter (T / m) can produce a frequency differentiation of the megahertz (MHz) level. To achieve a magnetic field gradient of 100 T / m, special magnetic field structure design is required, or near-field microwaves with high current need to be passed through the chip surface, both of which are relatively difficult to implement. In addition, when the frequency difference between the two ions is significant (i.e., relatively large), the currently common geometric phase gate in the industry is difficult to implement or scale up on a large scale in such an ion trap system, i.e., it is difficult to achieve multi-bit entanglement operations. Therefore, the number of ions that can be independently manipulated by this approach is currently small.

[0047] This approach addresses some of the challenges in related technologies by providing a novel ion manipulation method that utilizes global lasers or microwaves to achieve logical manipulation of multiple ions under low magnetic field gradients. Compared to frequency-addressed approaches in related technologies, this approach can independently manipulate a greater number of ions under the same magnetic field gradient. This approach increases the number of manipulated ions while maintaining high fidelity. Put another way, this approach increases the number of qubits while maintaining the quality of quantum manipulation, achieving higher-fidelity ion manipulation.

[0048] This solution can be applied to various quantum information technologies, including quantum computing, quantum simulation, quantum sensing, precision measurement, etc.

[0049] Next, the implementation environment involved in the embodiments of this application is introduced.

[0050] FIG1 is a system architecture diagram of an ion manipulation method provided in an embodiment of the present application. The system may be referred to as an ion trap system. Referring to FIG1 , the system includes a laser, a modulator, a controller, an ion trap (not shown), and a plurality of ions. The laser and the controller are both connected to the modulator. The plurality of ions are in a magnetic field having a magnetic field gradient, and the plurality of ions are confined within a limited space of the ion trap under the action of the magnetic field. Each of the plurality of ions has a multi-energy-level structure.

[0051] 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 a control signal of multiple frequencies and transmit the control signal of multiple frequencies to the modulator. The modulator is used to frequency-modulate the first original laser signal using the control signal 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 calculation space to the auxiliary space. The multiple first ions are ions that are irrelevant to quantum manipulation, the ions in the calculation space and the ions in the auxiliary space are at different energy levels, and the multiple frequencies are frequencies that match the transition frequencies of the multiple first ions.

[0052] The laser is further configured to generate a second original laser signal and transmit the second original laser signal to the modulator. Under the control of the controller, the modulator is configured to modulate the second original laser signal by amplitude, phase, or frequency to generate a second manipulation signal, and to use the second manipulation signal to perform quantum manipulation on multiple second ions in the computational space. The second manipulation signal is a global laser signal.

[0053] The laser can be a single-frequency laser with good coherence, outputting a laser signal of a specific wavelength. To achieve energy level transitions in the ions, the frequency of the laser signal output by the laser is matched to the ion transition frequency, creating a resonance between the laser frequency and the ion transition frequency. Alternatively, the laser can be a tunable laser capable of outputting a laser signal of the desired wavelength.

[0054] The modulator is an acousto-optic modulator (AOM) or an electro-optic modulator (EOM) or other forms of modulator. The modulator is mainly used to modulate the amplitude, frequency or phase of the received laser signal to obtain the laser signal required for quantum manipulation (such as ion initialization, quantum gate, quantum state readout, etc.), such as the first manipulation signal and the second manipulation signal mentioned above.

[0055] In one possible implementation, the controller includes a timing control unit and a waveform control unit, and the controller is configured to generate control signals via the timing control unit and / or the waveform control unit. The timing control unit is configured to turn the laser signal on and off in time according to the control logic. The waveform control unit is configured to control the modulator according to a specified quantum algorithm, including amplitude, phase, and frequency control. When achieving spatial transfer through energy level transitions, the waveform control unit generates control signals at multiple frequencies that match the transition frequencies of the multiple first ions that require energy level transitions.

[0056] In one possible implementation, the controller includes one or more signal sources configured to generate control signals at multiple frequencies. For example, the controller may include two signal sources, each configured to generate control signals at a specific frequency. The controller also includes an adder, and the control signals at these specific frequencies are summed and transmitted to the modulator.

[0057] The above-mentioned magnetic field gradient is generated by a permanent magnet or a coil with current passing through it. The ions at different positions feel different magnetic fields, and the 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 embodiment of the present application, the Zeeman energy level is selected. This multi-energy level is generated by the angular momentum coupling of electrons or atomic nuclei inside the ions. The transition frequency involved in this solution can refer to the optical band or the microwave band. It should be noted that if it is a microwave band, the above-mentioned laser needs to be replaced with a microwave device. This solution divides the multiple sub-energy levels included in the multi-energy level into a computing space and an auxiliary space. The computing space is used for the processing of quantum information, that is, quantum manipulation, and the auxiliary space is used to carry ions that are not related to quantum manipulation.

[0058] The plurality of ions are identical ions and serve as information carriers in quantum information technology.

[0059] In one possible implementation, the laser can be replaced with a microwave device, thereby utilizing the microwave signals generated by the microwave device to achieve the spatial transfer and quantum manipulation described above. Alternatively, a microwave device can be added to the system, i.e., the system includes both a laser and a microwave device, thereby utilizing both the laser and the microwave device to jointly achieve the spatial transfer and / or quantum manipulation described above.

[0060] FIG2 is a diagram of the system architecture involved in another ion manipulation method provided in an embodiment of the present application. The system architecture includes a computing entity and a quantum computer. The computing entity and the quantum computer are connected wirelessly or wired. In some embodiments, the quantum computer includes the ion trap shown in FIG1 . In other embodiments, the system architecture further includes the laser, modulator, and controller shown in FIG1 .

[0061] The computing entity is configured to receive a quantum information processing task input by a user and provide the quantum information processing task to the quantum computer. In some embodiments, the computing entity is further configured to obtain an execution result of the quantum information processing task output by the quantum computer and display the output of the quantum computer to the user.

[0062] A quantum computer is used to execute a quantum information processing task input by a user using the ion manipulation methods provided in the embodiments of this application. For example, the quantum computer determines the ions that need to be spatially transferred based on the quantum information processing task, adjusts the energy levels of these ions according to their transition frequencies, determines the operations required for the ions in the computational space based on the quantum information processing task, and then performs the corresponding operations on these ions, such as multi-bit quantum entanglement operations and single-bit flip operations. In some embodiments, the quantum computer is also used to output the execution results of the quantum information processing task to the computing entity.

[0063] Please refer to Figure 3, which is a schematic diagram of the structure of an electronic device according to an embodiment of the present application. This electronic device can become part or all of the computing entity shown in Figure 3, or become 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.

[0064] The processor 301 is a general-purpose central processing unit (CPU), a network processing processor (NP), a microprocessor, or one or more integrated circuits for implementing the solution of the present application, such as an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The PLD is a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL), or any combination thereof.

[0065] Communication bus 302 is used to transmit information between the above components. In some embodiments, communication bus 302 is divided into an address bus, a data bus, a control bus, etc. For ease of illustration, only one thick line is used in the figure, but this does not mean that there is only one bus or one type of bus.

[0066] The memory 303 is a read-only memory (ROM), random access memory (RAM), electrically erasable programmable read-only memory (EEPROM), an optical disc (including a compact disc read-only memory (CD-ROM), a compact disc, a laser disc, a digital versatile disc, a Blu-ray disc, etc.), a magnetic disk storage medium, or other magnetic storage device, or any other medium that can be used to carry or store 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 via the communication bus 302, or the memory 303 is integrated with the processor 301.

[0067] Communication interface 304 uses any transceiver-like device for communicating with other devices or communication networks. Communication interface 304 includes a wired communication interface and / or a wireless communication interface. Examples of wired communication interfaces include Ethernet interfaces. In some embodiments, the Ethernet interface is an optical interface, an electrical interface, or a combination thereof. The wireless communication interface is a wireless local area network (WLAN) interface, a cellular network communication interface, or a combination thereof.

[0068] In some embodiments, the electronic device includes multiple processors, such as processor 301 and processor 305 shown in Figure 3. Each of these processors is a single-core processor or a multi-core processor. A processor herein refers to one or more devices, circuits, and / or processing cores for processing data (such as computer program instructions).

[0069] 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 a variety of 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. The input device 307 communicates with the processor 301 and can receive user input in a variety of ways. For example, the input device 307 is a mouse, a keyboard, a touch screen device, or a sensor device.

[0070] In some embodiments, memory 303 is used to store program code 310 for implementing the present invention. Processor 301 is capable of executing program code 310 stored in memory 303. This program code includes one or more software modules. In embodiments where the electronic device is part of a quantum computer, the electronic device can implement the ion manipulation method provided in the embodiment of FIG. 4 below using processor 301 and program code 310 in memory 303.

[0071] It should be understood that the implementation environment and business scenarios described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided by the embodiments of the present application. Ordinary technicians in this field can know that with the evolution of the implementation environment and the emergence of new business scenarios, the technical solutions provided by the embodiments of the present application are also applicable to similar technical problems.

[0072] Next, the ion manipulation method provided in the embodiments of the present application is introduced.

[0073] FIG4 is a flow chart of an ion manipulation method provided in an embodiment of the present application. The method is applied to an ion trap system, wherein the ion trap system includes a plurality of ions, the plurality of ions being in a magnetic field having a magnetic field gradient. The magnetic field gradient causes the plurality of ions to have different transition frequencies, and each of the plurality of ions has a multi-energy level structure. Referring to FIG4 , the method includes the following steps.

[0074] Step 401: adjusting the energy levels of the plurality of first ions according to their transition frequencies to transfer the plurality of first ions from the calculation space to the auxiliary space, wherein the energy levels of the ions in the calculation space and the ions in the auxiliary space are different.

[0075] The plurality of ions in the ion trap system include a plurality of first ions, which are ions irrelevant to the quantum manipulation in step 402. The plurality of ions also include a plurality of second ions, which are ions to be quantum manipulated in step 402.

[0076] As can be seen from the above, this solution utilizes the multi-energy-level structure of ions to perform spatial transfer. In the embodiment of the present application, the multi-energy level includes at least four sub-energy levels. The computational space corresponds to two first sub-energy levels of the at least four sub-energy levels, and the auxiliary space corresponds to two second sub-energy levels of the at least four sub-energy levels. The two first sub-energy levels are any two sub-energy levels of the at least four sub-energy levels, and the two second sub-energy levels are any two sub-energy levels of 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-energy level to form the computational space, and any other two sub-energy levels are selected to form the auxiliary space.

[0077] The multiple energy levels include a ground state energy level, a stable 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, a sub-energy level in the stable state energy level, or a sub-energy level in the metastable energy level. For ease of description, the sub-energy level included in the ground state energy level is referred to as the ground state sub-energy level, the sub-energy level included in the stable state energy level is referred to as the stable state sub-energy level, and the sub-energy level included in the metastable state energy level is referred to as the metastable sub-energy level.

[0078] In the embodiment of the present application, any four sub-levels are selected from the multi-level to form a calculation space and an auxiliary space. Taking the multi-level including N sub-levels as an example, the calculation space and the auxiliary space have a total of C 4 N possible combinations.

[0079] In one energy level division method, the multiple energy levels include four energy levels: 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 energy levels, and the F energy level is the stable state energy level.

[0080] For example, four sub-levels are selected from the S energy level and the D energy level to form the calculation space and the auxiliary space. The S energy level includes two sub-levels and the D energy level includes five sub-levels. Then, the calculation space and the auxiliary space have a total of C 4 There are 7 possible combinations. Figure 5 shows three of them. In these three combinations, 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, Q0 and Q1 represent a sub-energy level in the S energy level and a sub-energy level in the D energy level, respectively, and A0 and A1 represent another sub-energy level in the S energy level and another sub-energy level in the D energy level, respectively. In the second combination, 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, Q0 and Q1 represent a sub-energy level in the S energy level and a sub-energy level in the D energy level, respectively, and A0 and A1 represent the other two sub-energy levels in the D energy level.

[0081] If the stable and metastable states are called excited states, the calculation space (Q0-Q1) and the auxiliary space (A0-A1) can have the following combinations: (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 combination of the ground state neutron energy level and the excited state neutron energy level.

[0082] Before the spatial transfer, the multiple ions are all in the calculation space, that is, the multiple ions are at the same energy level, for example, the multiple ions are all in the calculation space represented by Q0 and Q1 in the first combination shown in FIG5 .

[0083] Since the transition frequencies of the multiple ions are different, the energy levels of the multiple first ions are adjusted according to the transition frequencies of the multiple first ions, so as to transfer the multiple first ions from the calculation space to the auxiliary space. For example, the multiple first ions are transferred from the calculation space represented by Q0 and Q1 to the auxiliary space represented by A0 and A1.

[0084] In one possible implementation, a manipulation device generates a first manipulation signal based on the transition frequencies of the plurality of first ions. The first manipulation signal has multiple frequencies that match the transition frequencies of the plurality of first ions, whereby the matching can generate resonance. The manipulation device uses the first manipulation signal to control the plurality of first ions to undergo energy level transitions, thereby transferring the plurality of first ions from the computation space to the auxiliary space.

[0085] The first manipulation signal includes a first laser signal and / or a first microwave signal. Based on this, the manipulation device uses the first manipulation signal to control the energy level transition of the plurality of first ions. There are three corresponding implementation methods, which are described below.

[0086] In a first implementation, the first manipulation signal is a first laser signal. The manipulation device includes a laser, a controller, and a modulator as shown in FIG1 . The laser generates a first original laser signal and transmits the first original laser signal to the modulator. The controller generates the aforementioned multiple frequency control signals and transmits the multiple frequency control signals to the modulator. The modulator frequency-modulates the first original laser signal using the multiple frequency control signals to obtain a first laser signal, and uses the first laser signal to control the energy level transitions of the multiple first ions, thereby transferring the multiple first ions from the computation space to the auxiliary space.

[0087] Specifically, the modulator irradiates the plurality of ions with a first laser signal, causing a plurality of first ions in 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. However, because the first laser signal does not have a frequency that matches the transition frequencies of a plurality of second ions in the plurality of ions, the plurality of second ions do not undergo energy level transitions and thus remain in the computational space.

[0088] In a second implementation, the first manipulation signal is a first microwave signal. The manipulation 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 the aforementioned multiple frequency control signals and transmits the multiple frequency control signals to the modulator. The modulator frequency-modulates the first original microwave signal using the multiple frequency control signals to generate a first microwave signal. The first microwave signal is used to control the energy level transitions of the multiple first ions, thereby transferring the multiple first ions from the computation space to the auxiliary space.

[0089] Specifically, the modulator transmits a first microwave signal to the plurality of ions, causing a plurality of first ions in 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. However, because the first microwave signal does not have a frequency that matches the transition frequencies of a plurality of second ions in the plurality of ions, the plurality of second ions do not undergo energy level transitions and thus remain in the computational space.

[0090] In a third implementation, 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 the 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 corresponds to the first original laser signal, and the other part corresponds to the first original microwave signal. The modulator frequency-modulates the first original laser signal by one part of the control signals of the multiple frequencies to obtain a first laser signal, and frequency-modulates the first original microwave signal by another part of the control signals of the multiple frequencies to obtain a first microwave signal. The first laser signal and the first microwave signal are used to control the energy level transition of the multiple first ions to transfer the multiple first ions from the calculation space to the auxiliary space.

[0091] The specific implementation method of using the first laser signal and the first microwave signal to control the energy level transition of the multiple first ions is similar to the corresponding contents in the above-mentioned first method and second method, and will not be repeated here.

[0092] In one possible implementation, the control device may include, in addition to the aforementioned components, other components, such as an input device for receiving user input for quantum information processing tasks, an output device, a communication interface, etc. The control device may be the quantum computer described above.

[0093] As can be seen from the above, the multiple ions in the embodiments of the present application include multiple identical ions, that is, the same isotope of the same element. For example, the multiple ions include multiple Ca-40, multiple Yb-171, or multiple Ba-133.

[0094] Among them, the Ca-40 ion is an atom with a nuclear spin of 0. There are many Zeeman energy levels in 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 level is directly proportional to the strength of the external magnetic field. Therefore, the transition between the ground state and the excited state of the Ca-40 ion can be selected to realize the above-mentioned spatial transfer. This transition is also called the electric quadruple transition.

[0095] For example, 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 by a microwave signal (i.e., a radio frequency signal) generated by a radio frequency antenna. Transitions between the two sub-energy levels included in the S energy level can also be driven by a microwave signal (i.e., a radio frequency signal) generated by a radio frequency antenna, or by a laser signal generated by a laser of another wavelength.

[0096] As can be seen above, before the spatial transfer in step 401, the multiple ions are at the same energy level. For example, the multiple ions are at the same energy level after initialization, or the multiple ions are restored to the same energy level through spatial transfer after a quantum manipulation. This will be described in detail below.

[0097] FIG6 is a flow chart of another quantum manipulation method provided in an embodiment of the present application. Referring to FIG6 , after a user inputs a quantum information processing task, the following process will be generated: initialization - calibration - quantum manipulation - quantum state readout.

[0098] Among them, initialization mainly realizes the stable confinement of the multiple ions, that is, the internal and external states of the multiple ions are initialized to the specified quantum state through the magnetic field. For example, the multiple ions are stably confined to a straight line by the magnetic field to form a one-dimensional ion chain, or the multiple ions are stably confined to a plane by the magnetic field to form a neatly arranged two-dimensional ion crystal, or the multiple ions are stably confined to a local space by the magnetic field to form a neatly arranged three-dimensional ion crystal. The specific implementation method of initialization can be referred to the relevant technology. After initialization, the multiple ions are at the same energy level.

[0099] Calibration mainly calibrates the transition frequency and rate of each ion. Since the magnetic field size at the location of each ion is different, the transition frequency of each ion is different. For an ion trap system including M ions, there are k*M transition frequencies that need to be calibrated, where k is the maximum number of transitions that may be used within a single ion, and k is usually equal to the number of multiple sub-energy levels included in the multi-energy level minus 1. The rate here refers to the intensity of the interaction between ions and lasers, that is, the Rabi rate. The difference in rate between different ions comes from the different laser intensities felt by different ions. The calibration of multiple ions can be performed in parallel or separately, which can be determined according to the actual situation. During the calibration process, ions may undergo energy level transitions, and after calibration, the multiple ions return to the same energy level.

[0100] Quantum manipulation includes single-bit gate manipulation (i.e. 1-bit gate manipulation) and multi-bit gate manipulation.

[0101] Among them, 1-bit gate manipulation is a means of utilizing frequency resonance to modulate the frequency of the global laser or microwave to a frequency that resonates with the transition frequency of the single ion to be manipulated, and the laser or microwave is used to perform 1-bit manipulation quantum logic operations on the single ion, thereby forming a single quantum bit. The specific implementation method of 1-bit gate manipulation can refer to the relevant technology, and the embodiments of this application will not be introduced in detail. It is worth noting that 1-bit gate manipulation does not require spatial transfer, and 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, 1-bit gate manipulation can also be spatially transferred, that is, ions other than the above-mentioned single ions are first transferred to the auxiliary space, and then the 1-bit manipulation quantum logic operation is performed on the single ion, and after the operation, the ions in the auxiliary space are transferred back to the computing space.

[0102] It is generally believed that if 1-bit gate manipulation and 2-bit gate manipulation can be achieved, quantum manipulation of any bit can be achieved. This article mainly describes the improvement of 2-bit gate manipulation.

[0103] The 2-bit gate manipulation involves the aforementioned 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, two-bit quantum manipulation is performed on multiple second ions in the computation space. After the manipulation, the multiple first ions are transferred back to the computation space, restoring them to the same energy level.

[0104] Figure 7 is a schematic diagram of an ion manipulation provided by an embodiment of the present application. In Figure 7, K1 to K5 represent 5 ions. When the ion represented by K1 is subjected to 1-bit gate manipulation (represented by the symbol R in the figure), there is no need to perform spatial transfer on other ions. When 2-bit gate manipulation is performed on the two ions represented by K3 and K5, it is necessary to first transfer the three ions represented by K1, K2 and K4 to the auxiliary space, and then perform 2-bit gate manipulation on the two ions represented by K3 and K5, and then transfer the three ions represented by K1, K2 and K4 back to the calculation space.

[0105] Quantum state readout involves collecting the fluorescence emitted by the ions to determine the specific quantum state they are in. In embodiments of the present application, a spatially differentiated detector is used to read out the quantum state of the ions. The detector can be implemented by a camera (e.g., an electron multiplying charge coupled device (EMCCD)), a multi-channel photomultiplier tube (PMT), or other devices.

[0106] Next, step 402 is used to introduce multi-bit quantum manipulation in more detail.

[0107] Step 402: Perform quantum manipulation on a plurality of second ions in the computation space to form a plurality of quantum bits, where the plurality of second ions are ions in the plurality of ions other than the plurality of first ions.

[0108] Since this solution does not require optical ion search, multi-bit quantum manipulation can be achieved by quantum manipulation of the multiple second ions using global laser and / or global microwave.

[0109] The global laser is generated by the laser described above, and the global microwave is generated by the radio frequency antenna described above.

[0110] Taking the example of quantum manipulation of multiple second ions using global laser light, the laser generates a second original laser signal and transmits it to a modulator. Under the control of a controller, the modulator modulates the amplitude, phase, or frequency of the second original laser signal to generate a second manipulation signal. This second manipulation signal is then used to perform quantum manipulation of multiple second ions in the computational space. This second manipulation signal is a global laser signal.

[0111] Next, we will introduce 2-bit door control in detail.

[0112] 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 quantum manipulation of multiple second ions in the computing 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, a being greater than 0 and less than 1; performing a single-bit flip operation on the multiple second ions after the quantum entanglement operation; and performing a quantum entanglement operation again on the multiple second ions after the single-bit flip operation 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. Simply put, the quantum entanglement operation is first performed on the two second ions at a portion of the angles, and then the single-bit flip operation is performed on the two second ions respectively, and then the quantum entanglement operation is performed on the two second ions at another portion of the angles.

[0113] In the embodiment of the present application, a is 0.5. That is, the angle of the two quantum entanglement operations is θ / 2, which is easy to implement and also facilitates theoretical calculation of the impact of these two quantum entanglement operations. Here, θ represents the angle required for two-bit entanglement.

[0114] Of course, in other embodiments, a may also be other values, such as 1 / 3 or 1 / 4.

[0115] As can be seen, the 2-bit gate operation in this scheme includes a 2-bit quantum entanglement operation + a 1-bit flip operation + a 2-bit quantum entanglement operation, while the 2-bit gate operation in the related art includes a single 2-bit quantum entanglement operation. The following will explain the reason for this scheme.

[0116] Here, we use the MS logic gate as an example to analyze the specific implementation of 2-bit quantum manipulation. Due to the frequency difference between the two secondary ions, the evolution operator generated by global laser or global microwave will differ from the ideal case.

[0117] Taking global laser as an example, when two ions with different transition frequencies are irradiated by global laser, the Hamiltonian of the system can be expressed as expression (1).

[0118] In expression (1), σ x and σ z represents the Pauli operator 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 strength of the coupling between the ion and the vibration mode, and a and denote the annihilation and production operators on the vibration mode, respectively; ε denotes the difference between the global laser and the ion frequency; Ω(t) denotes the intensity of the global laser, where the intensity varies with time t. The global laser can be a smooth pulse as shown in FIG8 .

[0119] Under the action of the Hamiltonian of the above system, after the two ions experience global laser irradiation for time t, the quantum operation operator can be expressed as expression (2). U(t) = exp{H I +H N} (2)

[0120] In expression (2), H I represents the ideal part of quantum logic manipulation, H N Indicates the difference due to frequency difference. I and H N They are expressed as Expression (3) and Expression (4) respectively.

[0121] In expressions (3) and (4), β(t) and κ(t) are related to the waveform of the global laser. During operation, by selecting appropriate laser parameters, both β(t) and κ(t) can be made equal to 0. For specific implementation, please refer to the relevant 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 can be eliminated during the operation through a method 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 scheme, that is, performing 2-bit quantum entanglement operation, 1-bit flip operation, and 2-bit quantum entanglement operation in sequence.

[0122] Figure 9 is a schematic diagram of 2-bit quantum manipulation in an embodiment of the present application. Referring to Figure 9, for the two ions represented by K3 and K5, an MS logic gate operation is first performed at an angle of θ / 2, and then a single-bit flip operation (represented by the symbol π in the figure) is performed on each of the two ions, and then an MS logic gate operation is performed at an angle of θ / 2, thereby completing the two-bit quantum manipulation of the two ions. The middle single-bit flip operation combined with the two MS logic gate operations before and after can eliminate the above H N The remaining This error.

[0123] The above describes the implementation of 2-bit quantum manipulation. The idea of ​​spatial transfer followed by error cancellation can also be extended to quantum manipulation of more bits, meaning the number of secondary ions can be greater than two. This is not discussed in detail here. However, it is worth emphasizing that arbitrary bit quantum manipulation can often be achieved by combining 1-bit and 2-bit quantum manipulation. Therefore, in practical applications, any conceivable quantum information processing task can be accomplished by combining 1-bit and 2-bit quantum manipulation.

[0124] After quantum manipulation of the above-mentioned multiple second ions to form multiple quantum bits, in order to perform the next quantum manipulation, it is necessary to transfer the above-mentioned multiple first ions back to the calculation space. That is, according to the transition frequency of the multiple first ions, the energy levels of the multiple first ions are adjusted to transfer the multiple first ions from the auxiliary space back to the calculation space. The specific implementation method is similar to step 401, except that if step 401 is to transition a certain first ion from a low energy level to a high energy level, then here the first ion is transitioned 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.

[0125] Exemplarily, ions in the auxiliary spaces corresponding to A0 and A1 are transferred to the calculation spaces corresponding to Q0 and Q1 by global laser or global microwave.

[0126] It is worth noting that because this scheme utilizes the multi-level structure of ions and the difference in transition frequencies between ions to perform spatial transfer, so that multiple second ions are at different energy levels from multiple first ions, quantum manipulation can be achieved without a strong magnetic field gradient. For example, compared to the magnetic field gradient of about 100 T / m required in related technologies, this scheme can achieve quantum manipulation with a magnetic field gradient of less than 100 T / m, such as a medical magnetic field gradient of 0.04 T / m, or a more conventional magnetic field gradient of 0.01 T / m.

[0127] 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 microns (um), the difference in transition frequency between ions is Where μ represents the Polz electron, represents the magnetic field gradient, and Δz represents the distance between adjacent ions.

[0128] At a frequency resolution of 10 kHz, for 1-bit quantum manipulation, a laser pulse of approximately 100 μs, such as a 100 μs square wave, can 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.

[0129] This scheme can be applied to the manipulation of one-dimensional ionic chains as well as to the manipulation of two-dimensional ionic crystals. The feasibility of applying this scheme to the manipulation of two-dimensional ionic crystals will be introduced below.

[0130] The two-dimensional ionic crystal is confined in a limited space by a magnetic field. The magnetic field has magnetic field gradients in both dimensions of the two-dimensional ionic crystal. As shown in FIG10 , the magnetic field has magnetic field gradients in both the x-direction and the y-direction, which are represented by G respectively. x and G yConsidering the first-order sensitive energy levels within the ion to the magnetic field as quantum bits, the frequency of each energy level within the ion needs to be different. The magnitude of the magnetic field felt by the ion at coordinates (x, y) is expressed as expression (5).

[0131] In formula (5), B0 represents the basic bias magnetic field, which is used to define the quantization axis of the ions.

[0132] Then, the transition frequency ω of the ion at the coordinate (x, y) can be expressed as Expression (6).

[0133] It can be seen from formula (6) that there are differences in the transition frequencies of ions at different positions, and this difference can be demonstrated by the spectrum lines shown in FIG11 .

[0134] Through the above analysis, it is found that applying a magnetic field with a magnetic field gradient in a two-dimensional ionic crystal can cause differences in the transition frequencies of multiple ions in the two-dimensional ionic crystal, so this scheme can be applied to two-dimensional ionic crystals.

[0135] Similarly, this approach can also be extended to three-dimensional ionic crystals. Specifically, by applying a magnetic field with a magnetic field gradient to the crystal, the transition frequencies of multiple ions within the crystal differ. This frequency difference, combined with the ions' multi-level structure, can then be exploited to achieve quantum manipulation of specific ions through spatial transfer.

[0136] The core concept of this solution can also be applied to other hardware systems besides ion traps, such as atomic systems, diamond systems, and nuclear magnetic resonance systems. The core concept is to use magnetic field gradients to create frequency differences among multiple objects in the system. This frequency difference and the multi-level structure within each object can then be exploited to manipulate a specific object through spatial transfer.

[0137] In summary, in the embodiments of the present application, by adjusting the energy levels of the ions, the ions that are not related to quantum manipulation are transferred to the auxiliary space, and the ions in the computing space are quantum manipulated. It can be seen that this solution does not require ion light search, that is, no complex chip processing means are required. This solution also does not require light search for ions, that is, it does not require laser strong focusing technology, and has low requirements for laser pointing stability. This solution can achieve multi-ion manipulation using global laser or microwaves, which is easy to implement and can ensure system stability without laser strong focusing. And because of the spatial transfer, this solution can achieve multi-ion manipulation using a smaller magnetic field gradient, which greatly reduces the threshold for ion manipulation and provides a new approach for quantum information processing.

[0138] FIG12 is a schematic diagram of the structure of an ion manipulation device provided in an embodiment of the present application. The ion manipulation device can be implemented as part or all of a manipulation device by software, hardware, or a combination of both. The manipulation device can be the manipulation device described in the above embodiment. In the embodiment of the present application, the ion manipulation device is applied to an ion trap system, which includes a plurality of ions, each of which is in a magnetic field having a magnetic field gradient. The magnetic field gradient causes the transition frequencies of the plurality of ions to differ, and each of the plurality of ions has a multi-energy level structure. Referring to FIG12 , the device includes: a spatial transfer module 1201 and a quantum manipulation module 1202.

[0139] a space transfer module 1201 for adjusting energy levels of a 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, wherein the plurality of ions include the plurality of first ions, and the ions in the calculation space and the ions in the auxiliary space are at different energy levels;

[0140] The quantum manipulation module 1202 is used to perform quantum manipulation on a plurality of second ions in the computing space to form a plurality of quantum bits. The plurality of second ions are ions other than the plurality of first ions in the plurality of ions.

[0141] In one possible implementation, the quantum manipulation module 1202 is specifically configured to:

[0142] The plurality of second ions are quantum manipulated using global laser and / or global microwave.

[0143] In a possible implementation, the space transfer module 1201 is specifically configured to:

[0144] 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;

[0145] The first manipulation signal is used to control the plurality of first ions to perform energy level transition, so as to transfer the plurality of first ions from the calculation space to the auxiliary space.

[0146] In a possible implementation, the first manipulation signal includes a first laser signal and / or a first microwave signal.

[0147] In one possible implementation, the number of the plurality of second ions is 2, and the quantum manipulation includes a quantum entanglement operation;

[0148] The quantum manipulation module 1202 is specifically used for:

[0149] performing a quantum entanglement operation on the plurality of second ions according to 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;

[0150] Performing single-bit flipping operations on the multiple second ions after the quantum entanglement operation;

[0151] The quantum entanglement operation is performed again on the multiple second ions after the single-bit flip operation according to the second angle, and the sum of the second angle and the first angle is equal to the angle required for two-bit entanglement.

[0152] In one possible implementation, a is 0.5.

[0153] In a possible implementation, the space transfer module 1201 is further configured to:

[0154] After performing quantum manipulation on the multiple second ions in the computing space to form multiple quantum bits, the energy levels of the multiple first ions are adjusted according to the transition frequencies of the multiple first ions to transfer the multiple first ions from the auxiliary space back to the computing space.

[0155] In one possible implementation, the above-mentioned multi-energy level includes at least four sub-energy levels, the calculation 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, 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 except the two first sub-energy levels.

[0156] In one possible implementation, the above-mentioned multiple energy levels include a ground state energy level, a stable 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, a sub-energy level in the stable state energy level, or a sub-energy level in the metastable energy level.

[0157] In a possible implementation, the plurality of ions include a plurality of identical ions.

[0158] In an embodiment of the present application, by adjusting the energy level of the ions, the ions that are not related to quantum manipulation are transferred to the auxiliary space, and the ions in the computing space are quantum manipulated. It can be seen that this solution does not require ion light search, that is, no complex chip processing means are required. This solution also does not require light search for ions, that is, it does not require laser strong focusing technology, and has low requirements for laser pointing stability. This solution can achieve multi-ion manipulation using global laser or microwave, which is easy to implement and can ensure system stability without laser strong focusing. And because of the spatial transfer, this solution can achieve multi-ion manipulation using a smaller magnetic field gradient, which greatly reduces the threshold for ion manipulation and provides a new approach for quantum information processing.

[0159] It should be noted that the ion manipulation device provided in the above embodiment is illustrated only by the division of the above functional modules when manipulating ions. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. In addition, the ion manipulation device provided in the above embodiment and the ion manipulation method embodiment are based on the same concept. The specific implementation process is detailed in the method embodiment and will not be repeated here.

[0160] In the above embodiments, all or part of the embodiments can be implemented by software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments can be implemented 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, all or part of the processes or functions described in the embodiments of the present application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium can 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 available media integrated therein. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, or a magnetic tape), an optical medium (e.g., a digital versatile disc (DVD)), or a semiconductor medium (e.g., a solid state disk (SSD)). It is worth noting 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-transient storage medium.

[0161] It should be understood that the "at least one" mentioned herein refers to one or more, and "a plurality of" refers to two or more. In the description of the embodiments of the present application, unless otherwise specified, " / " means or, for example, A / B can mean A or B; "and / or" in this article is merely a description of the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in order to facilitate a clear description of the technical solutions of the embodiments of the present application, in the embodiments of the present application, words such as "first" and "second" are used to distinguish between identical or similar items with substantially the same functions and effects. Those skilled in the art will understand that words such as "first" and "second" do not limit the quantity and execution order, and words such as "first" and "second" do not necessarily limit them to be different.

[0162] 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 used 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.

[0163] The above description is an embodiment provided for this application and is not intended to limit this application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application should be included in the scope of protection 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: 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 a computational space to an auxiliary space, the plurality of ions including the plurality of first ions, and the ions in the computational space and the ions in the auxiliary space being at different energy levels; Performing 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 in the plurality of ions other than the plurality of first ions.

2. The method according to claim 1, wherein 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, wherein The a is 0.

5.

7. The method according to any one of claims 1 to 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: 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.

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, characterized in that 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 structure; the device 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 ions in the calculation space and the ions in the auxiliary space are at different energy levels; A quantum manipulation module, configured to perform quantum manipulation on multiple second ions in the calculation space to form multiple qubits, and the multiple second ions are the ions among the multiple ions other than the multiple first ions.

12. The device according to claim 11, characterized in that, Specifically, the quantum manipulation module is 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, Specifically, the spatial transfer module is configured to: Generate a first manipulation signal according to the transition frequencies of the multiple first ions, and the first manipulation signal has 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, characterized in that, 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; Specifically, the quantum manipulation module is configured to: Perform a quantum entanglement operation on the multiple second ions according to a first angle, and the first angle is a times the angle required for two-bit entanglement, where a is greater than 0 and less than 1; Perform a single-bit flip operation on each of the multiple second ions after the quantum entanglement operation; Perform a quantum entanglement operation on the multiple second ions after the single-bit flip operation again according to a second angle, and the sum of the second angle and the first angle is equal to the angle required for two-bit entanglement.

16. The device according to claim 15, characterized in that, 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 the 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 computational space corresponds to two first sub-levels among the at least four sub-levels, 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, and 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, the magnetic field gradient causes the transition frequencies of the plurality of ions to be different, and 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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