Ion trap quantum computing system and device, control method and storage medium

Abstract

The invention discloses an ion trap quantum computing system and device, a control method and a storage medium. The system comprises a group of global cooling light, a target ion storage area and a control area, wherein the target ion storage area and the control area are formed by quantum charge-coupled devices, and the target ion storage area and the control area are both located in light spots of the global cooling light; the target ion storage area is used for storing target ions and moving the target ions to the control area; the control area is used for executing quantum logic gate operation on the target ions; and transferring the target ions carrying quantum state information to a dark state, wherein the dark state is a state in which resonance interaction does not occur between the target ions and the global cooling light. According to the scheme, a target ion storage area and a control area are covered by global cooling light at the same time, so that a laser light path system can be simplified; target ions carrying quantum state information are transferred to a dark state which is not influenced by global cooling light, so that the time that the global cannot be cooled is shortened.

Description

Technical Field

[0001] The present invention relates to the field of quantum computing technology, and in particular to an ion trap quantum computing system, device, control method and storage medium. Background Technology

[0002] Quantum charge-coupled devices (QCCDs), as a key innovation in ion trap architecture, can achieve dynamic spatial recombination of qubits through the integration of microfabricated electrode arrays. Their core mechanism lies in the precise transport of ions from the storage region to the control region via segmented potential traps, thus physically isolating the ions performing gate operations from the stored ions and suppressing electromagnetic interference from neighboring ions.

[0003] Under normal circumstances, separate cooling light is needed for the storage area to cool the ions in the storage area, and separate cooling light is needed for the control area to cool the ions in the control area. Providing separate cooling light for the storage area and the control area through the laser optical path system increases the complexity of the laser optical path system, especially when there are a large number of storage areas and control areas. Summary of the Invention

[0004] This invention provides an ion trap quantum computing system, device, control method, and storage medium, which can simplify the laser optical path system that provides cooling light and reduce the time when the entire area cannot be cooled.

[0005] In a first aspect, embodiments of the present invention provide an ion trap quantum computing system, comprising: a set of global cooling light, and a target ion storage region and a manipulation region composed of quantum charge-coupled devices, wherein the target ion storage region and the manipulation region are both located within the light spot of the global cooling light;

[0006] The target ion storage area is used to store target ions and move the target ions to the control area;

[0007] The control region is used to perform quantum logic gate operations on the target ion; to transfer the target ion carrying quantum state information to a dark state, wherein the dark state is a state in which the target ion does not resonate with the global cooling light.

[0008] In a second aspect, embodiments of the present invention provide an ion trap quantum computing device, including the system described in the first aspect.

[0009] Thirdly, embodiments of the present invention provide an ion trap quantum computing control method applied to an ion trap quantum computing system. The system includes a set of global cooling beams and a target ion storage region and a manipulation region composed of quantum charge-coupled devices. Both the target ion storage region and the manipulation region are located within the beam spot of the global cooling beams. The method includes:

[0010] The target ion is stored in the target ion storage area and then moved to the control area.

[0011] Through the control region, quantum logic gate operations are performed on the target ion; the target ion carrying quantum state information is transferred to a dark state, which is a state in which the target ion does not resonate with the global cooling light.

[0012] Fourthly, embodiments of the present invention provide a computer-readable storage medium storing an ion trap quantum computing control program thereon, which, when executed by a processor, implements the method described in the third aspect.

[0013] The technical solution of this invention places both the target ion storage region and the manipulation region, both composed of quantum charge-coupled devices (QCPs), within the spot of the global cooling light. The target ion storage region stores target ions and moves them to the manipulation region. The manipulation region performs quantum logic gate operations on the target ions and transfers the target ions carrying quantum state information to a dark state, where the target ions do not resonate with the global cooling light. This solution simplifies the laser optical path system by simultaneously covering both the target ion storage region and the manipulation region with a single set of global cooling light. Furthermore, transferring the target ions carrying quantum state information to a dark state unaffected by the global cooling light allows the global cooling light to be activated even when the target ions carry quantum state information, reducing the time during which the global cooling light cannot be applied.

[0014] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1This is a schematic diagram of a quantum charge-coupled device and a laser spot focusing distribution method according to Embodiment 1 of the present invention;

[0017] Figure 2 This is a method provided according to Embodiment 1 of the present invention. 40 Ca + A schematic diagram of energy levels;

[0018] Figure 3 This is a flowchart of an ion trap quantum computing control method provided in Embodiment 3 of the present invention. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0020] It should be noted that the terms "first," "second," etc., used in this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0021] Example 1

[0022] This invention provides an ion trap quantum computing system, comprising: a set of global cooling light, and a target ion storage region and a manipulation region composed of quantum charge-coupled devices, wherein the target ion storage region and the manipulation region are both located within the light spot of the global cooling light;

[0023] The target ion storage area is used to store target ions and move the target ions to the control area;

[0024] The control region is used to perform quantum logic gate operations on the target ion; to transfer the target ion carrying quantum state information to a dark state, wherein the dark state is a state in which the target ion does not resonate with the global cooling light.

[0025] The ion trap quantum computing system in this embodiment of the invention includes a target ion storage region and a manipulation region composed of quantum charge-coupled devices, as well as a set of global cooling lights.

[0026] The target ion storage region is used to store target ions, which can be understood as ions that will subsequently undergo quantum logic gate operations. When a quantum logic gate operation is required, the target ion storage region can move the target ion to the manipulation region. The number of target ion storage regions can be one or more, and is not limited here.

[0027] The manipulation region is used to perform quantum logic gate operations on target ions. Moving the target ion to be manipulated from the target ion storage region to the manipulation region avoids interference from other target ions. There can be one or more manipulation regions.

[0028] It should be noted that quantum logic gate operations are the core foundation of quantum computing, enabling specific processing of qubits to realize the processing and computation of quantum information. For example, at the level of specific gate experiment implementation, quantum logic gate operations can be two-qubit entangled gates, three-qubit fully connected controlled NOT gates, four-qubit multi-controlled phase gates, etc., without limitation here.

[0029] Global cooling light can be understood as cooling light covering both the target ion storage region and the manipulation region, both of which are located within the spot of the global cooling light. Generally, when global cooling light simultaneously covers both the target ion storage region and the manipulation region, if the target ion in the manipulation region is in a state of manipulation, quantum state maintenance, or readout, the global cooling light must be turned off. This is because global cooling light alters the quantum state of the target ion or causes it to emit stimulated photons, thus decohering. When global cooling light is turned off due to the manipulation region being in a state of manipulation, quantum state maintenance, or readout, the target ion storage region cannot be cooled by global cooling light for an extended period, increasing the probability of global ion loss.

[0030] To address the aforementioned issues, this embodiment of the invention provides a control region that transfers target ions carrying quantum state information to a dark state. The dark state is a state in which the target ions do not resonate with the global cooling light. In other words, the target ions carrying quantum state information are transferred to a dark state unaffected by the global cooling light, allowing the global cooling light to be activated even when the target ions carry quantum state information.

[0031] In one embodiment, the global cooling light is continuously turned on, and the global cooling light is turned off when the target ion in the manipulation area is being manipulated and read out;

[0032] Alternatively, the global cooling light may be periodically turned on, and when the target ion in the control area is being controlled and read out, the global cooling light may be turned off.

[0033] The target ion is transferred to the dark state by state transfer light during the quantum state maintenance process.

[0034] The global cooling light is continuously or periodically turned on, and turned off when the target ion in the manipulation region is being manipulated or readout. When the target ion in the manipulation region is in a quantum state, it is transferred to a dark state by the state transfer light. At this time, the target ion and the global cooling light do not resonate with each other, so the global cooling light does not need to be turned off during quantum state maintenance. Since manipulation and readout are relatively short periods compared to quantum state maintenance, turning off the global cooling light only during manipulation and readout significantly reduces the time during which the entire region cannot be cooled.

[0035] The technical solution of this invention places both the target ion storage region and the manipulation region, both composed of quantum charge-coupled devices (QCPs), within the spot of the global cooling light. The target ion storage region stores target ions and moves them to the manipulation region. The manipulation region performs quantum logic gate operations on the target ions and transfers the target ions carrying quantum state information to a dark state, where the target ions do not resonate with the global cooling light. This solution simplifies the laser optical path system by simultaneously covering both the target ion storage region and the manipulation region with a single set of global cooling light. Furthermore, transferring the target ions carrying quantum state information to a dark state unaffected by the global cooling light allows the global cooling light to be activated even when the target ions carry quantum state information, reducing the time during which the global cooling light cannot be applied.

[0036] In one embodiment, the system further includes a junction region connecting the target ion storage region and the control region, and a co-cooled ion storage region co-located with the control region, wherein the control region is located between the junction region and the co-cooled ion storage region.

[0037] The co-cooling ion storage area is used to store co-cooling ions and move the co-cooling ions to the control area;

[0038] The control area is also used to enable the co-cooling ions to co-cool the target ion, and to remove the co-cooling ions from the control area after the co-cooling is completed and before performing quantum logic gate operations on the target ion.

[0039] The co-cooling ion storage region is used to store co-cooling ions, which can be ions that co-cool the target ion. The co-cooling ion storage region can move the co-cooling ions to the manipulation region, so that the co-cooling ions can co-cool the target ion in the manipulation region.

[0040] Each control zone is co-located with a co-cooled ion storage zone. The control zone is located between the binding zone and the co-cooled ion storage zone. The binding zone is the area that connects the target ion storage zone and the control zone.

[0041] The control area is also used to enable the co-cooling ions to co-cool the target ions. Co-cooling is a technique that achieves rapid cooling by coupling the motion modes between ions. Its core lies in using laser to cool an easily manipulated ion, namely the co-cooling ion, and utilizing Coulomb interactions to transfer the cooling effect to the target ion, which is difficult to cool directly. This overcomes the adverse effects of heating caused by the movement of the target ion. Specifically, the implementation methods of co-cooling can include:

[0042] 1. Laser pre-cooling and synergistic cooling of ions: First, a laser of a specific frequency is applied to the synergistically cooled ions to cool them to a "crystalline" state (a low-temperature state close to the ground state). This process utilizes the Doppler effect and photon recoil effect to absorb the kinetic energy of the ions.

[0043] 2. Coupling of inter-ion motion modes: The target ion and the cooled co-cooled ions are confined together in a linear ion trap. Due to the long-range characteristics of the Coulomb force, the motion modes of the two ions form a collective vibration through electric field constraint, resulting in the uniform distribution of kinetic energy through inter-ion interaction.

[0044] 3. Energy Transfer and Cooling Conduction: The low-temperature state of the co-cooled ions is transferred to the target ion through shared vibrational modes, allowing the latter to be synchronously cooled to near its ground state without direct laser intervention. This process avoids background noise interference caused by the similar wavelengths of the probe and cooling light when directly cooling the target ion.

[0045] Synergistic cooling has the following advantages:

[0046] 1. Eliminating crosstalk: By separating the physical carriers of data qubits and auxiliary qubits, coordinated cooling can complete auxiliary operations without interfering with the computation of ionic states.

[0047] 2. Improved compatibility: This method is applicable to isotope mixed ion systems, providing a more compatible cooling solution for scenarios requiring coordinated operation, such as quantum error correction and ion-photon entanglement.

[0048] 3. Efficiency optimization: Compared with single-ion cooling, the Coulomb coupling mechanism significantly shortens the cooling time, enabling the system to reach the low-entropy state required for quantum gate operation more quickly.

[0049] Cooperative cooling can effectively suppress the motion heating of target ions through the collective vibrational modes of Coulomb coupling, but it also has the adverse effect of "enhanced dephase noise": the vibrational modes of the cooperatively cooled ions and the target ions are coupled to transmit photon scattering noise, which leads to an increase in the dephase rate of the quantum state and directly affects the fidelity of single / double qubit gates.

[0050] Therefore, in order to address the aforementioned problem of "dephase noise enhancement", this application, after the co-cooled ions and the target ion that needs to perform quantum logic gate operations are moved to the control region, makes the co-cooled ions co-cool the target ion. After the co-cooling is completed, the co-cooled ions are first moved out of the control region and returned to the co-cooled ion storage region, and then the target ion in the control region is subjected to quantum logic gate operations, thereby avoiding interference of the co-cooled ions with the quantum logic gate operations.

[0051] In one embodiment, there are multiple target ion storage regions, and the multiple target ion storage regions are radially arranged and connected to the control region of the binding region.

[0052] In a quantum charge-coupled device, multiple target ion storage regions and manipulation regions are arranged radially around the binding region. For example, multiple target ion storage regions are arranged radially to the right of the binding region, and manipulation regions are arranged radially to the left of the binding region. The binding region connects the manipulation region and multiple target ion storage regions, but this is not limited here.

[0053] In one embodiment, there are multiple control regions, and the multiple control regions are radially arranged and connected to the binding region with the target ion storage region;

[0054] Each of the aforementioned control areas is provided with a corresponding collaborative cooling ion storage area;

[0055] Each of the control areas is provided with a set of target control lights for performing quantum logic gate operations and a set of target readout lights for reading out quantum states.

[0056] In a quantum charge-coupled device (QCC), a target ion storage region and multiple manipulation regions are arranged radially around a binding region. For example, the target ion storage region is radially arranged to the right of the binding region, and the multiple manipulation regions are radially arranged to the left of the binding region. The binding region connects the multiple manipulation regions and the target ion storage region, and each manipulation region is equipped with a corresponding co-cooled ion storage region (this is not limited here). Furthermore, each manipulation region is equipped with a set of target manipulation beams that cover the manipulation region for performing quantum logic gate operations; and each region is also equipped with a set of target readout beams that cover the manipulation region for reading out quantum states.

[0057] The above content can be understood as an explanation of the specific structure of the quantum charge-coupled device and the function of each component of this structure. Based on the above architecture, the following content further explains the focusing distribution method of the global cooling light in this embodiment.

[0058] In ion trap quantum computing, co-cooling typically uses ions that are different from the target ion (such as ions of different elements or ions of the same element but different isotopes). Using ions that are the same as the target ion may lead to the following problems:

[0059] 1. Increased risk of quantum state interference: Co-cooling requires frequent laser manipulation of the energy level transitions of the co-cooled ions; if the co-cooled ions and the target ions are of the same type, the laser may act on the quantum states of both simultaneously, leading to the unexpected excitation or decoherence of the target ion qubits.

[0060] 2. Limited addressing accuracy: In two-dimensional ion arrays, single-ion addressing requires strict suppression of crosstalk error; spectral overlap of the same type of ion may exacerbate laser crosstalk, making it difficult to meet the addressing accuracy requirements of high-fidelity quantum gate operation.

[0061] The system architecture provided in this application does not suffer from the aforementioned problems because, during the execution of quantum logic gate operations, the co-cooling ion and the target ion are located at different positions, thus avoiding both the "risk of quantum state interference" and the "limited addressing accuracy." Therefore, the system architecture provided in this application can use the same ion as the target ion as the co-cooling ion, which has the following advantages:

[0062] 1. Cooperative cooling relies on the Coulomb interaction between two ions to achieve energy transfer. According to classical collision theory, when the masses of the two particles are similar, their momentum exchange efficiency is the highest. If the mass difference is too large, most of the kinetic energy is still retained in the target ion after the collision, resulting in a decrease in cooling efficiency. When ions with similar masses collide through Coulomb force, the kinetic energy can be efficiently transferred to the cooperative cooling ion, thereby more thoroughly dissipating the disordered kinetic energy of the target ion.

[0063] 2. Ions trapped in the ion trap form chain-like or crystal structures through Coulomb forces. The energy distribution of their collective vibration modes is directly related to the mass ratio: Ions with similar masses have more matched vibration frequencies, which allows the co-cooling ions and the target ions to participate in the same collective motion mode synchronously, avoiding local energy accumulation; mass matching reduces the thermal relaxation time between different ions, promoting the system to reach the global low-temperature equilibrium state more quickly.

[0064] In summary, the closer the mass of the co-cooling ion is to that of the target ion being cooled, the better the cooling effect. This is primarily due to the close relationship between momentum exchange efficiency and energy transfer matching. Therefore, using ions identical to the target ion as co-cooling ions can achieve the optimal cooling effect.

[0065] In one embodiment, the synergistic cooling ion is the same as the target ion; the spot of the global cooling light also includes all of the synergistic cooling ion storage regions.

[0066] In other words, by covering the entire control area, the co-cooled ion storage area, and the target ion storage area with a set of global cooling light, global cooling of the co-cooled ions in storage, the target ions in storage, the co-cooled ions in co-cooling, and the target ions in co-cooling can be achieved, which greatly simplifies the requirements for focusing the cooling light spot and simplifies the complexity of the laser beam splitting optical path.

[0067] Figure 1 This is a schematic diagram of a quantum charge-coupled device and a laser spot focusing distribution method according to Embodiment 1 of the present invention. Figure 1 As shown, in a quantum charge-coupled device (QCDP), with the binding region as the center, the target ion storage region is radially arranged to the right of the binding region, and two manipulation regions are radially arranged to the left of the binding region. The binding region connects the two manipulation regions and the target ion storage region, and each manipulation region is equipped with a corresponding co-cooled ion storage region. Each manipulation region is equipped with a set of target readout light and target manipulation light. A set of global cooling light covers the entire manipulation region, the co-cooled ion storage region, and the target ion storage region.

[0068] In one embodiment, the control area is specifically used for:

[0069] The co-cooling ions and the target ions are placed in the same potential well for co-cooling, with the co-cooling ions located on the side away from the binding region and the target ions located on the side facing the binding region.

[0070] After the co-cooling is completed and before the quantum logic gate operation is performed on the target ion, the co-cooled ion is separated from the target ion by controlling the voltage of the radio frequency electrode and the DC electrode in the control region. The separated co-cooled ion leaves the control region and returns to the corresponding co-cooled ion storage region, and the separated target ion returns to the potential well of the control region.

[0071] Combination Figure 1It is known that the potential well of the ion trap is mainly composed of radio frequency (RF) electrodes, assisted by direct current (DC) electrodes. The movement of ions is mainly accomplished by the instantaneous pulse electric field of the DC electrode at a specific position. Typically, the DC electrode will be given an additional voltage of 0-5V on top of the steady state (the position of the ion in the ion trap remains stable), lasting for about 0-50us. Typically, the DC electrode at the acceleration phase and position lasts for about 10us, while the DC electrode at the deceleration phase and position lasts for more than 20us. The specific parameters of which DC electrodes to apply the moving voltage at what time can be obtained through simulation and experimentation.

[0072] To achieve synergistic cooling, both the synergistic cooling ions and the target ions can be moved to the same potential well in the control region in a manner known in the prior art, and the two ions will not be misaligned, i.e., the synergistic cooling ions are located on the side away from the binding region, while the target ions are located on the side facing the binding region.

[0073] After co-cooling is completed and before performing quantum logic gate operations on the target ion, the RF electrode voltage of the control region is turned off or reduced. This reduces or eliminates the potential energy (also known as the depth of the potential well) used to trap the co-cooled ion and the target ion. Under the interaction of the Coulomb force between the ions, the co-cooled ion will spontaneously move to the side away from the binding region, while the target ion will spontaneously move to the side facing the binding region. Combined with the acceleration of the DC electrode, the co-cooled ion and the target ion can be separated quickly. Then, the RF electrode voltage of the control region is restored, so that the potential energy of the control region is restored. Combined with the guidance of the DC electrode, the separated target ion returns to the potential well of the control region, and the separated co-cooled ion returns to the co-cooled ion storage region at the end away from the binding region.

[0074] In the above separation process, in order to minimize the movement distance of the target ions and thus reduce the heating effect caused by the movement of the target ions, ideally, during the period when the RF electrode voltage of the control region is turned off or reduced, the target ions are kept at the position of the lowest potential energy point of the potential well by the assistance of the DC electrode facing the binding region, while only the co-cooled ions move and reset to leave the potential well of the control region.

[0075] Since the co-cooling ions and target ions are separated from each other during the target ion manipulation stage, there is no vibration mode coupling to transmit photon scattering noise, thus overcoming the above-mentioned problem of "dephase noise enhancement".

[0076] In one embodiment, the synergistic cooling ions are moved to the control zone before the target ions.

[0077] This means that before the target ion enters the control zone, the co-cooling ions can be moved to the control zone, so that the target ion is quickly and co-cooled as soon as it enters the control zone, thus making the target ion controllable.

[0078] In one embodiment, the dark state is a metastable state. A metastable state is a special state that lies between stability and instability.

[0079] Both the synergistic cooling ions and the target ions are 40 Ca + The dark state will be further illustrated using an example. It should be noted that other ions known in the art for use in ion trap quantum computing can also employ the above scheme; no limitation is made here.

[0080] Figure 2 This is a method provided according to Embodiment 1 of the present invention. 40 Ca + A schematic diagram of energy levels, such as Figure 2 As shown, 40 Ca + There are several key low energy levels, namely ground state 4. 2 S 1 / 2 Excited state 4 2 P 1 / 2 (Short lifetime), metastable 3 2 D 3 / 2 (Lifespan approximately 1 second) and 3 2 D 5 / 2 (Lifespan approximately 1 second.)

[0081] In one embodiment, both the synergistic cooling ion and the target ion are 40 Ca + The global cooling light is based on 4 2 S 1 / 2 and 4 2 P 1 / 2 The Doppler cooling light transitions, and the dark state is 3. 2 D 5 / 2 Energy level state.

[0082] At 4 2 S 1 / 2 Synergistic cooling ions and based on 4 2 S 1 / 2 and 4 2 P 1 / 2 Doppler-cooled light interaction during transitions, co-cooling ions transition to 4 2 P 1 / 2 The ions absorb photons in the opposite direction of their motion, reducing their momentum. Then they spontaneously emit photons (i.e., they are in a "bright state" with random photon directions). After multiple cycles, the ion velocity decreases (the temperature decreases).

[0083] The light is transferred to the dark state by the state transition, i.e., 3 2 D 5 / 2 The target ion in the energy level state is almost transparent to the Doppler cooling light mentioned above and will not scatter photons (i.e., it is in the "dark state").

[0084] In one embodiment, the global cooling light further includes making 40 Ca + From 3 2 D 3 / 2 Jump to 4 2 P 1 / 2 The excitation light.

[0085] At 4 2 P 1 / 2 The synergistic cooling ions have a certain probability of decreasing from 4 2 P 1 / 2 Relaxation to metastable state 3 2 D 3 / 2 3 2 D 3 / 2 The state has a long lifetime and will break away from the cooling cycle of the co-cooling ions, but it can be excited by light. 40 Ca + From 3 2 D 3 / 2 Heavy pump to 4 2 P 1 / 2 This allows the synergistic cooling ions to re-participate in the cooling cycle.

[0086] The light is transferred to the dark state by the state transition, i.e., 3 2 D 5 / 2 The target ion in the energy level state is also almost transparent to the above excitation light and will not scatter photons (i.e., it is in the "dark state").

[0087] In one embodiment, both the synergistic cooling ion and the target ion are 40 Ca + The wavelength of the state transfer light that transfers the target ion to the dark state is 729 nm; the global cooling light includes light with wavelengths of 397 nm and 866 nm.

[0088] Among them, light with a wavelength of 729nm is the light that will... 40 Ca + The state transfer light transferred to the dark state, with a wavelength of 397 nm, is based on 4 2 S 1 / 2 and 4 2 P 1 / 2 The Doppler cooling light of the transition, with a wavelength of 866 nm, is the light that causes the transition. 40 Ca + From 3 2 D 3 / 2Jump to 4 2 P 1 / 2 The excitation light.

[0089] The above-mentioned maintenance of quantum states based on dark states involves the following three main operations:

[0090] 1. Temporary storage of target ion state

[0091] A 729nm laser beam is precisely irradiated onto the target ion, driving the target ion carrying quantum state information to achieve 4 2 S 1 / 2 up to 3 2 D 5 / 2 The transition allows the quantum state information of the target ion to be temporarily stored in this long-lived dark state 3. 2 D 5 / 2 In the middle. Among them, quantum state information is usually encoded in 4. 2 S 1 / 2 A certain sublevel of the state or 4 2 S 1 / 2 With 3 2 D 5 / 2 The superposition state between them.

[0092] 2. Synergistic cooling

[0093] The kinetic energy (temperature) of the entire ion lattice (including the target ion and the co-cooling ion) is reduced. By turning on the cooling lasers at 397 nm and 866 nm, the ions interact with each other through Coulomb forces in the same trap of the manipulation region. The co-cooling ions, which are continuously cooled by the laser, transfer their kinetic energy to the target ion through Coulomb scattering, thereby effectively cooling the entire ion lattice to a low temperature.

[0094] Synergistic cooling ions: at 4 2 S 1 / 2 In its ground state, it interacts with the 397 / 866nm laser and is continuously subjected to Doppler cooling, resulting in a decrease in temperature.

[0095] Target ion: located at 3 2 D 5 / 2 The target ion does not resonate with the 397 / 866nm laser. Therefore, the cooling laser does not directly affect the internal quantum state of the target ion (i.e., the state stored in the 3nm laser). 2 D 5 / 2 (Information about the state) will not cause it to scatter photons and thus decoherence.

[0096] 3. Perform logic gate operations

[0097] The target ion was temporarily stored for 3 2 D 5 / 2The target ion is then removed from the control region after co-cooling is complete. Quantum logic gate operations are then performed on the target ion within the control region using a laser for qubit encoding. Because co-cooling is ongoing or has just been completed, the motion state of the target ion remains at a low level, which is crucial for improving the fidelity of the quantum logic gates.

[0098] Based on the above energy level construction and methods, the following are exemplary illustrations of practical application scenarios:

[0099] First, move the two target ions to the two control areas respectively. At this point, the two target ions can be cooled directly with global cooling light, or they can be cooled using the synergistic cooling method described above.

[0100] Then, one target ion is moved to the first control region, which can be cooled directly with global cooling light or with co-cooling. Then, the global cooling light is turned off (or the gaps in the periodic opening of the global cooling light are selected), and entangled state preparation is performed in the first control region (if co-cooling is used, the co-cooling ion needs to be removed first). After the entangled state preparation is completed, the two ions in the first control region are stored in the dark state. At this time, the global cooling light can be turned on. This time is very short, so it has little impact on the operation of the global cooling light (i.e., cooling other ions).

[0101] Then, one of the ions from the first control region is transferred to the second control region, and the above operation is repeated so that the two ions in the second control region are also in an entangled state and in a dark state.

[0102] When it is necessary to manipulate any ion in any control region, simply leave the ion alone in that control region and then perform the operation in the manner described above as "execute logic gate operation".

[0103] If you need to operate on two ions, simply place them in the same control area or in different control areas, and then operate them in the manner described above for "performing logic gate operations".

[0104] If it is necessary to operate on three ions, the three ions can be placed in the same control area or in different control areas, and then the operation can be performed in the manner described above as "performing logic gate operations".

[0105] This same principle applies to any number of ions.

[0106] Example 2

[0107] This invention provides an ion trap quantum computing device, including the ion trap quantum computing system provided by this invention. In practical applications, this can be understood as integrating the ion trap quantum computing system into the ion trap quantum computing device.

[0108] Ion trap quantum computing devices can include, but are not limited to, various forms of computers, such as desktop computers, mainframe computers, workbenches, servers, and other suitable computers.

[0109] There are no restrictions on the integration method and connection relationship of the ion trap quantum computing system in the ion trap quantum computing device, as long as the corresponding functions of the ion trap quantum computing system can be realized.

[0110] Example 3

[0111] Figure 3 This is a flowchart of an ion trap quantum computing control method according to Embodiment 3 of the present invention. The method is applied to an ion trap quantum computing system, which includes a set of global cooling beams and a target ion storage region and a manipulation region composed of quantum charge-coupled devices. Both the target ion storage region and the manipulation region are located within the beam spot of the global cooling beams.

[0112] like Figure 3 As shown, the method includes:

[0113] S310. Store target ions in the target ion storage area and move the target ions to the control area.

[0114] S320. Through the control region, perform quantum logic gate operation on the target ion; transfer the target ion carrying quantum state information to a dark state, wherein the dark state is a state in which the target ion does not resonate with the global cooling light.

[0115] The technical solution of this invention places both the target ion storage region and the manipulation region, both composed of quantum charge-coupled devices (QCPs), within the spot of the global cooling light. The target ion storage region stores target ions and moves them to the manipulation region. The manipulation region performs quantum logic gate operations on the target ions and transfers the target ions carrying quantum state information to a dark state, where the target ions do not resonate with the global cooling light. This solution simplifies the laser optical path system by simultaneously covering both the target ion storage region and the manipulation region with a single set of global cooling light. Furthermore, transferring the target ions carrying quantum state information to a dark state unaffected by the global cooling light allows the global cooling light to be activated even when the target ions carry quantum state information, reducing the time during which the global cooling light cannot be applied.

[0116] Furthermore, the global cooling light remains on, and when the target ion in the control area is being controlled and read out, the global cooling light is turned off;

[0117] Alternatively, the global cooling light may be periodically turned on, and when the target ion in the control area is being controlled and read out, the global cooling light may be turned off.

[0118] The target ion is transferred to the dark state by state transfer light during the quantum state maintenance process.

[0119] Furthermore, the system also includes a junction region connecting the target ion storage region and the control region, and a co-cooled ion storage region co-located with the control region, the control region being located between the junction region and the co-cooled ion storage region; the method further includes:

[0120] The co-cooled ion storage area stores co-cooled ions, and the co-cooled ions are moved to the control area.

[0121] The control region enables the co-cooling ions to co-cool the target ion, and after the co-cooling is completed and before the quantum logic gate operation is performed on the target ion, the co-cooling ions are removed from the control region.

[0122] Furthermore, there are multiple target ion storage regions, and the multiple target ion storage regions are radially arranged and connected to the control region of the binding region.

[0123] Furthermore, there are multiple control regions, and the multiple control regions are radially arranged and connected to the binding region with the target ion storage region;

[0124] Each of the aforementioned control areas is provided with a corresponding collaborative cooling ion storage area;

[0125] Each of the control areas is provided with a set of target control lights for performing quantum logic gate operations and a set of target readout lights for reading out quantum states.

[0126] Furthermore, the synergistic cooling ions are the same as the target ions;

[0127] The spot of the global cooling light also includes all of the synergistically cooled ion storage regions.

[0128] Furthermore, the dark state is a metastable state.

[0129] Furthermore, both the synergistic cooling ions and the target ions are... 40 Ca + The global cooling light is based on 4 2 S 1 / 2 and 4 2 P 1 / 2 The Doppler cooling light transitions, and the dark state is 3. 2 D 5 / 2 Energy level state.

[0130] Furthermore, the global cooling light also includes... 40 Ca + From 3 2 D 3 / 2 Jump to 4 2 P 1 / 2 The excitation light.

[0131] Furthermore, both the synergistic cooling ions and the target ions are... 40 Ca + The wavelength of the state transfer light that transfers the target ion to the dark state is 729 nm; the global cooling light includes light with wavelengths of 397 nm and 866 nm.

[0132] Furthermore, the method of co-cooling ions co-cooling the target ion, and removing the co-cooled ions from the manipulation region after co-cooling is completed and before performing quantum logic gate operations on the target ion, includes:

[0133] The co-cooling ions and the target ions are placed in the same potential well for co-cooling, with the co-cooling ions located on the side away from the binding region and the target ions located on the side facing the binding region.

[0134] After the co-cooling is completed and before the quantum logic gate operation is performed on the target ion, the co-cooled ion is separated from the target ion by controlling the voltage of the radio frequency electrode and the DC electrode in the control region. The separated co-cooled ion leaves the control region and returns to the corresponding co-cooled ion storage region, and the separated target ion returns to the potential well of the control region.

[0135] Furthermore, the synergistic cooling ions are moved to the control zone before the target ions.

[0136] The ion trap quantum computing control method and ion trap quantum computing system provided in this embodiment of the invention have corresponding beneficial effects, which will not be elaborated here.

[0137] This invention also provides a computer-readable storage medium storing an ion trap quantum computing control program, which, when executed by a processor, implements the ion trap quantum computing control method provided in this invention.

[0138] In the context of this invention, a computer-readable storage medium can be a tangible medium that may contain or store an ion trap quantum computing control program for use by or in conjunction with an instruction execution system, apparatus, or device. The computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination thereof. Alternatively, the computer-readable storage medium may be a machine-readable signal medium. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0139] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0140] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. An ion trap quantum computing system, characterized in that, include: A set of global cooling light, and a target ion storage region and a manipulation region composed of quantum charge-coupled devices, wherein the target ion storage region and the manipulation region are both located within the light spot of the global cooling light; The target ion storage area is used to store target ions and move the target ions to the control area; The control region is used to perform quantum logic gate operations on the target ion; to transfer the target ion carrying quantum state information to a dark state, wherein the dark state is a state in which the target ion does not resonate with the global cooling light.

2. The system according to claim 1, characterized in that, The global cooling light is continuously turned on, and when the target ion in the control area is being controlled and read out, the global cooling light is turned off. Alternatively, the global cooling light may be periodically turned on, and when the target ion in the control area is being controlled and read out, the global cooling light may be turned off. The target ion is transferred to the dark state by state transfer light during the quantum state maintenance process.

3. The system according to claim 1, characterized in that, The system also includes a junction area connecting the target ion storage region and the control region, and a co-cooled ion storage region co-located with the control region, wherein the control region is located between the junction area and the co-cooled ion storage region; The co-cooling ion storage area is used to store co-cooling ions and move the co-cooling ions to the control area; The control area is also used to enable the co-cooling ions to co-cool the target ion, and to remove the co-cooling ions from the control area after the co-cooling is completed and before performing quantum logic gate operations on the target ion.

4. The system according to claim 3, characterized in that, The target ion storage region comprises multiple regions, and these multiple target ion storage regions are radially arranged and connected to the control region in the bonding region.

5. The system according to claim 3, characterized in that, The control area is multiple, and the multiple control areas are radially arranged and connected to the binding area with the target ion storage area; Each of the aforementioned control areas is provided with a corresponding collaborative cooling ion storage area; Each of the control areas is provided with a set of target control lights for performing quantum logic gate operations and a set of target readout lights for reading out quantum states.

6. The system according to claim 5, characterized in that, The synergistic cooling ion is the same as the target ion; The spot of the global cooling light also includes all of the synergistically cooled ion storage regions.

7. The system according to claim 6, characterized in that, The dark state is a metastable state.

8. The system according to claim 7, characterized in that, Both the synergistic cooling ions and the target ions are 40 Ca + The global cooling light is based on 4 2 S 1 / 2 and 4 2 P 1 / 2 The Doppler cooling light transitions, and the dark state is 3. 2 D 5 / 2 Energy level state.

9. The system according to claim 8, characterized in that, The global cooling light also includes making 40 Ca + From 3 2 D 3 / 2 Jump to 4 2 P 1 / 2 The excitation light.

10. The system according to claim 7, characterized in that, Both the synergistic cooling ions and the target ions are 40 Ca + The wavelength of the state transfer light that transfers the target ion to the dark state is 729 nm; the global cooling light includes light with wavelengths of 397 nm and 866 nm.

11. The system according to claim 3, characterized in that, The control area is specifically used for: The co-cooling ions and the target ions are placed in the same potential well for co-cooling, with the co-cooling ions located on the side away from the binding region and the target ions located on the side facing the binding region. After the co-cooling is completed and before the quantum logic gate operation is performed on the target ion, the co-cooled ion is separated from the target ion by controlling the voltage of the radio frequency electrode and the DC electrode in the control region. The separated co-cooled ion leaves the control region and returns to the corresponding co-cooled ion storage region, and the separated target ion returns to the potential well of the control region.

12. The system according to claim 3, characterized in that, The synergistic cooling ions are moved to the control zone before the target ions.

13. An ion trap quantum computing device, characterized in that, Includes the system described in any one of claims 1-12.

14. A quantum computing control method using an ion trap, characterized in that, An application is made to an ion trap quantum computing system, the system comprising a set of global cooling beams, and a target ion storage region and a manipulation region composed of quantum charge-coupled devices, wherein both the target ion storage region and the manipulation region are located within the beam spot of the global cooling beams; the method includes: The target ion is stored in the target ion storage area and then moved to the control area. Through the control region, quantum logic gate operations are performed on the target ion; the target ion carrying quantum state information is transferred to a dark state, which is a state in which the target ion does not resonate with the global cooling light.

15. A computer-readable storage medium, characterized in that, It stores an ion trap quantum computing control program, which, when executed by a processor, implements the method as described in claim 14.

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