Synergistic cooling system, device and method for same ions and storage medium

Abstract

The invention discloses a collaborative cooling system, device and method for same ions and a storage medium. The system comprises an ion trap chip, state transfer light and same ion cooling light, wherein target ions and collaborative cooling ions which are the same as the target ions exist in the ion trap chip; the state transfer light is used for transferring the target ions to a dark state under the condition that the target ions are maintained in a quantum state, so that the target ions and the same ion cooling light do not generate resonance interaction; and the same ion cooling light is used for simultaneously irradiating the target ions and the collaborative cooling ions under the condition that the target ions are transferred to a dark state, so that the collaborative cooling ions and the same ion cooling light generate resonance interaction and carry out collaborative cooling on the target ions. According to the scheme, the problem of quantum state interference caused by co-cooling of same ions can be solved.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of quantum computing, and in particular to a system, device, method and storage medium for cooperative cooling of the same kind of ions. BACKGROUND

[0002] In ion trap quantum computing, cooperative cooling is a technology for achieving rapid cooling by coupling different ion motion modes. The core is to cool one ion that is easy to manipulate, i.e., a cooperative cooling ion, by laser, and to transfer the cooling effect to another ion that is difficult to cool directly, i.e., a target ion, by using Coulomb interaction, so as to efficiently suppress the motion heating of the target ion.

[0003] In general, the cooperative cooling ion is different from the target ion, such as ions of different elements or ions of the same element but different isotopes. If the same ion as the target ion is used as the cooperative cooling ion, the laser may act on the quantum state of the cooperative cooling ion and the target ion at the same time due to the need for frequent manipulation of the energy level transition of the cooperative cooling ion by laser, resulting in accidental excitation or decoherence of the quantum bit of the target ion, i.e., an increased risk of quantum state interference. SUMMARY

[0004] The present application provides a system, device, method and storage medium for cooperative cooling of the same kind of ions, which can solve the problem of quantum state interference caused by cooperative cooling of the same kind of ions.

[0005] In a first aspect, embodiments of the present application provide a system for cooperative cooling of the same kind of ions, comprising: an ion trap chip, state transfer light and same kind of ion cooling light, wherein the ion trap chip contains a target ion and a cooperative cooling ion which is the same as the target ion;

[0006] The state transfer light is configured to transfer the target ion to a dark state when the target ion is in a quantum state maintenance state, so that the target ion does not interact with the same kind of ion cooling light.

[0007] The same kind of ion cooling light is configured to irradiate the target ion and the cooperative cooling ion at the same time when the target ion is transferred to a dark state, so that the cooperative cooling ion interacts with the same kind of ion cooling light and cooperatively cools the target ion.

[0008] In a second aspect, embodiments of the present application provide a device for cooperative cooling of the same kind of ions, comprising the system as described in the first aspect.

[0009] Thirdly, embodiments of the present invention provide a method for synergistic cooling of the same type of ions, applied to a synergistic cooling system for the same type of ions. The system includes an ion trap chip, a state transfer light, and a cooling light for the same type of ions. The ion trap chip contains a target ion and synergistic cooling ions identical to the target ion.

[0010] The state-transfer light transfers the target ion to a dark state while maintaining its quantum state, preventing the target ion from resonating with the cooling light of the same type of ion.

[0011] When the target ion is transferred to a dark state, the same ion cooling light simultaneously irradiates the target ion and the co-cooling ion, causing the co-cooling ion and the same ion cooling light to resonate and interact, thereby co-cooling the target ion.

[0012] Fourthly, embodiments of the present invention provide a computer-readable storage medium storing a cooperative cooling program for the same type of ions, which, when executed by a processor, implements the method described in the third aspect.

[0013] The technical solution of this invention involves transferring the target ion to a dark state while maintaining its quantum state, preventing resonant interaction between the target ion and the cooling light of the same type of ion. While the target ion is in the dark state, the target ion and the co-cooling ion are simultaneously irradiated by the cooling light of the same type of ion, causing the co-cooling ion to resonate with the cooling light of the same type of ion and thus co-cooling the target ion. In this solution, the co-cooling ion resonates with the cooling light of the same type of ion, lowering its temperature and cooling the target ion. Under the co-cooling effect of the co-cooling ion, the target ion does not resonate with the cooling light of the same type of ion, and the cooling light of the same type of ion does not directly affect the internal quantum state of the target ion, nor does it cause decoherence due to photon scattering.

[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 1is a structure schematic diagram of a quantum charge coupled device provided by the embodiment one of the present application 40 Ca + a level diagram of the quantum charge coupled device;

[0017] Figure 2 is a structure schematic diagram of a quantum charge coupled device provided by the embodiment one of the present application

[0018] Figure 3 is a structure schematic diagram of another quantum charge coupled device provided by the embodiment one of the present application

[0019] Figure 4 is a schematic diagram of a focusing distribution mode of a laser spot provided by the embodiment one of the present application

[0020] Figure 5 is a schematic diagram of another focusing distribution mode of a laser spot provided by the embodiment one of the present application

[0021] Figure 6 is a flow chart of a method for cooperative cooling of same kind of ions provided by the embodiment three of the present application. DETAILED DESCRIPTION

[0022] In order to make the person skilled in the art better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by the person skilled in the art without creative labor should belong to the scope of protection of the present application.

[0023] It should be noted that the terms "first", "second" and the like in the present application are used to distinguish similar objects, and do not necessarily have to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0024] Embodiment one

[0025] The embodiment of the present application provides a cooperative cooling system of same kind of ions, comprising: an ion trap chip, state transfer light and same kind of ion cooling light, target ions and cooperative cooling ions same as the target ions exist in the ion trap chip;

[0026] The state transition light is used to transfer the target ion to a dark state in the case that the target ion is in a quantum state maintenance, so that the target ion does not interact with the same ion cooling light.

[0027] The same ion cooling light is used to irradiate the target ion and the cooperative cooling ion at the same time in the case that the target ion is transferred to a dark state, so that the cooperative cooling ion interacts with the same ion cooling light and cooperatively cools the target ion.

[0028] The cooperative cooling system in the application includes an ion trap chip, state transition light and same ion cooling light. The ion trap chip is a quantum chip based on ion trap technology, which uses the energy level and vibration state of ions to store and operate quantum information. The state transition light is light that can realize the state transition of ions. The same ion cooling light is light that can be used for same ion cooling.

[0029] There are target ions and cooperative cooling ions which are the same as the target ions in the ion trap chip. The target ion can be understood as an ion that needs to perform quantum logic gate operation. The cooperative cooling ion can be an ion that cooperatively cools the target ion.

[0030] Cooperative cooling is a technology that realizes rapid cooling by coupling the motion modes of ions. The core is to cool an easily manipulated ion, i.e. a cooperative cooling ion, by laser, and to use the Coulomb interaction to transfer the cooling effect to a target ion that is difficult to cool directly, so as to overcome the adverse effects of the heating effect caused by the movement of the target ion through cooperative cooling. Specifically, the implementation of cooperative cooling can include:

[0031] 1. Laser pre-cooling of the cooperative cooling ion: first, apply a laser of a specific frequency to the cooperative cooling ion to cool it to a "crystalline" state (a low-temperature state close to the ground state), which absorbs the kinetic energy of the ion by using the Doppler effect and the photon recoil effect.

[0032] 2. Coupling of inter-ion motion modes: the target ion and the cooled cooperative cooling ion are jointly confined in a linear ion trap. Due to the long-range nature of the Coulomb force, the motion modes of the two ions form collective vibrations through electric field confinement, resulting in uniform distribution of kinetic energy through inter-ion interaction.

[0033] 3. Energy transfer and cooling conduction: the low-temperature state of the cooperative cooling ion transfers energy dissipation to the target ion through shared vibration modes, so that the latter is cooled to the vicinity of the ground state synchronously without direct laser intervention. This process avoids the background noise interference caused by the proximity of the probe light and the cooling light when directly cooling the target ion.

[0034] Synergistic cooling has the following advantages:

[0035] 1. Elimination of crosstalk: By separating the physical carriers of the data qubits and auxiliary qubits, synergistic cooling can complete auxiliary operations without disturbing the state of the calculation ions.

[0036] 2. Compatibility improvement: This method is suitable for isotopic mixed ion systems, providing a more compatible cooling solution for scenarios that require synergistic operations, such as quantum error correction and ion-photon entanglement.

[0037] 3. Efficiency optimization: Compared to single-ion cooling, the Coulomb coupling mechanism significantly shortens the cooling time, allowing the system to reach the low-entropy state required for quantum gate operations more quickly.

[0038] In general, synergistic cooling ions use different ions from the target ions, such as ions of different elements or ions of the same element but different isotopes. If the same ion as the target ion is used as the synergistic cooling ion, the laser may simultaneously act on the quantum states of the synergistic cooling ion and the target ion due to the need for frequent laser manipulation of the energy level transitions of the synergistic cooling ion, leading to accidental excitation or decoherence of the target ion qubits, i.e., increased risk of quantum state interference.

[0039] To address the above problems, in the present application, the target ion is transferred to a dark state that does not interact with the same ion cooling light through a state transfer light while the target ion is in a quantum state, i.e., the target ion carries quantum state information.

[0040] In the case where the target ion is transferred to the dark state, the target ion and the synergistic cooling ion are simultaneously irradiated by the same ion cooling light. Since the synergistic cooling ion is not transferred to the dark state, it can interact with the same ion cooling light to lower its temperature. The synergistic cooling ion with reduced temperature can assist in the cooling of the target ion. Since the target ion is transferred to the dark state, it does not interact with the same ion cooling light during the synergistic cooling process, and the same ion cooling light does not directly affect the quantum state of the target ion or cause it to scatter photons and decohere. Therefore, the problem of increased risk of quantum state interference can be overcome.

[0041] The technical scheme of the embodiment of the present application is that, in the case that the target ion is in a quantum state maintenance, the target ion is transferred to a dark state, so that the target ion does not interact with the same ion cooling light; in the case that the target ion is transferred to the dark state, the same ion cooling light is used to irradiate the target ion and the collaborative cooling ion at the same time, so that the collaborative cooling ion interacts with the same ion cooling light and collaboratively cools the target ion. In the scheme, the collaborative cooling ion interacts with the same ion cooling light, the temperature is reduced, and the target ion can be cooled; the target ion is not affected by the same ion cooling light, and the same ion cooling light does not cause the target ion to de-cohere by scattering photons.

[0042] The technical scheme of the embodiment of the present application uses the same ion as the target ion as the collaborative cooling ion, which has the following advantages:

[0043] 1. The collaborative cooling relies on the energy transfer between the two ions through the Coulomb interaction. According to the classical collision theory, when the masses of the two particles are similar, the 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 the cooling efficiency; when the masses of the ions are similar, the kinetic energy can be efficiently transferred to the collaborative cooling ion through the Coulomb force collision, so that the disordered kinetic energy of the target ion is more thoroughly dissipated.

[0044] 2. The ions trapped in the ion trap form a chain or a crystal structure through the Coulomb force, and the energy distribution of the collective vibration mode is directly related to the mass ratio: the ions with similar masses have a more matched vibration frequency, so that the collaborative cooling ion and the target ion can participate in the same collective motion mode synchronously, avoiding the local accumulation of energy; the mass matching reduces the thermal relaxation time between different ions, promoting the system to reach a global low-temperature equilibrium state faster.

[0045] In summary, the closer the mass of the collaborative cooling ion to that of the target ion to be cooled, the better the cooling effect, which is closely related to the momentum exchange efficiency and energy transfer matching. Therefore, using the same ion as the target ion as the collaborative cooling ion can achieve the optimal cooling effect.

[0046] In one embodiment, the dark state is a metastable state. The metastable state is a special state between stable and unstable.

[0047] For example, the collaborative cooling ion and the target ion are both 40 Ca + The dark state is further described. It should be noted that other ions commonly known in the art that can be used for ion trap quantum computing can also use the above scheme, which is not limited here.

[0048] Figure 1 is provided according to an embodiment of the present application 40 Ca + energy level diagram, as Figure 1 indicated, 40 Ca + There are several key low-lying energy levels, namely ground state 4 2 S 1 / 2 , excited state 4 2 P 1 / 2 (lifetime short), metastable state 3 2 D 3 / 2 (lifetime about 1 second) and 3 2 D 5 / 2 (lifetime about 1 second).

[0049] In one embodiment, the sympathetic cooling ions and the target ions are both 40 Ca + ; the same ion cooling light is Doppler cooling light based on 4 2 S 1 / 2 and 4 2 P 1 / 2 transitions, and the dark state is 3 2 D 5 / 2 energy level state.

[0050] The sympathetic cooling ions in 4 2 S 1 / 2 interact with the Doppler cooling light based on 4 2 S 1 / 2 and 4 2 P 1 / 2 transitions, the sympathetic cooling ions transition to 4 2 P 1 / 2 , absorb a photon against the direction of its motion, reduce momentum, and then spontaneously emit a photon (i.e. in "bright state", the direction of the photon is random), after multiple cycles, the ion speed is reduced (temperature is reduced).

[0051] The target ions transferred to the dark state, i.e. 3 2 D 5 / 2 energy level state, are almost transparent to the above-mentioned Doppler cooling light and do not scatter photons (i.e. in "dark state").

[0052] In one embodiment, the same ion cooling light further includes excitation light for 40 Ca + transitioning from 3 2 D 3 / 2 to 4 2 P 1 / 2 .

[0053] In 4 2 P 1 / 2The 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.

[0054] And transferred to the dark state, 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").

[0055] In one embodiment, both the synergistic cooling ion and the target ion are 40 Ca + The same ion cooling light includes light with wavelengths of 397 nm and 866 nm; the state transition light has a wavelength of 729 nm.

[0056] 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 / 2 Jump to 4 2 P 1 / 2 The excitation light.

[0057] The above content involves the following two main operations:

[0058] 1. Temporary storage of target ion state

[0059] 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 / 2The quantum state information is usually encoded in 4 2 S 1 / 2 a certain sub-level of 4 2 S 1 / 2 or a superposition state between 3 2 D 5 / 2 .

[0060] 2. Sympathetic cooling

[0061] The kinetic energy (temperature) of the whole ion lattice (including the target ion and the sympathetic cooling ion) is reduced. The cooling lasers of 397 nm and 866 nm are turned on, and the ions in the same trap interact with each other through Coulomb force. The sympathetic cooling ion, which is constantly cooled by the laser, will transfer kinetic energy to the target ion through Coulomb scattering, thereby effectively cooling the whole ion lattice to a low temperature state.

[0062] Sympathetic cooling ion: in the 4 2 S 1 / 2 ground state, so it will interact with the 397 / 866 nm laser and be continuously Doppler-cooled, reducing the temperature.

[0063] Target ion: in the 3 2 D 5 / 2 state, and does not interact with the 397 / 866 nm laser. Therefore, the cooling laser does not directly affect the internal quantum state of the target ion (i.e., the information stored in the 3 2 D 5 / 2 state), nor does it cause it to scatter photons and become decoherent.

[0064] The specific structure of the ion trap chip and the functions of each component of the structure are described as follows.

[0065] In one embodiment, the ion trap chip is a quantum charge coupled device, and the quantum charge coupled device comprises:

[0066] a target ion storage area, a control area, a combination area connecting the target ion storage area and the control area, and a sympathetic cooling ion storage area arranged in line with the control area, the control area being located between the combination area and the sympathetic cooling ion storage area;

[0067] The target ion storage area is configured to store the target ion and move the target ion to the control area through the combination area.

[0068] The sympathetic cooling ion storage area is configured to store the sympathetic cooling ion and move the sympathetic cooling ion to the control area.

[0069] The control area is used to transfer the target ion to a dark state by using the state transfer light when the target ion is in quantum state maintenance, and to make the synergistic cooling ion synergistically cool the target ion by using the same ion cooling light when the target ion is transferred to the dark state; the synergistic cooling ion is moved out of the control area after the synergistic cooling is completed, and then the quantum logic gate operation is performed on the target ion.

[0070] Among them, the quantum charge-coupled device (Quantum Charge-Coupled Device, QCCD) is a key innovation of ion trap architecture, which realizes the dynamic spatial recombination of quantum bits by integrating a microfabricated electrode array.

[0071] The target ion storage area is used to store target ions. When the quantum logic gate operation needs to be performed, the target ion storage area can move the target ion to the control area through the combination area, which is the area connecting the target ion storage area and the control area. The number of target ion storage areas is one or more, which is not limited here.

[0072] The synergistic cooling ion storage area is used to store synergistic cooling ions. The synergistic cooling ion storage area can move the synergistic cooling ion to the control area, so that the synergistic cooling ion can synergistically cool the target ion in the control area.

[0073] The number of control areas can be one or more, and each control area is co-linearly provided with a synergistic cooling ion storage area, and the control area is located between the combination area and the synergistic cooling ion storage area.

[0074] The control area is used to transfer the target ion to a dark state by using the state transfer light when the target ion is in quantum state maintenance, and to make the synergistic cooling ion synergistically cool the target ion by using the same ion cooling light when the target ion is transferred to the dark state; the synergistic cooling ion is moved out of the control area after the synergistic cooling is completed, and then the quantum logic gate operation is performed on the target ion. Since the synergistic cooling is ongoing or has just been completed, the motion state of the target ion is maintained at a low level, which is crucial for improving the fidelity of the quantum logic gate.

[0075] The reason for moving the synergistic cooling ions out of the manipulation area after the completion of the synergistic cooling and then performing quantum logic gate operations on the target ions is that the synergistic cooling can effectively suppress the kinetic heating of the target ions through the collective vibration mode of the Coulomb coupling, but there is also the adverse effect of "retro-phase noise enhancement": the coupling of the vibration modes of the synergistic cooling ions and the target ions can transfer photon scattering noise, causing the phase rate of the quantum state to increase, which directly affects the single / double quantum bit gate fidelity. In this application, the synergistic cooling ions are moved out of the manipulation area and returned to the synergistic cooling ion storage area after the completion of the synergistic cooling, and then the target ions in the manipulation area are subjected to quantum logic gate operations, thereby avoiding the interference of the synergistic cooling ions on the quantum logic gate operations.

[0076] In this application, the target ions that need to perform quantum logic gate operations are moved from the target ion storage area to the manipulation area through the combination area for manipulation, which can avoid the interference of other target ions on the target ions performing quantum logic gate operations.

[0077] It should be noted that quantum logic gate operations are the core basis of quantum computing, which can perform specific processing on quantum bits to achieve the processing and operation of quantum information. For example, at the specific gate experiment implementation level, the quantum logic gate operation can be a two-bit entanglement gate, a three-bit full connection controlled non-gate, a four-bit multi-control phase gate, etc., which is not limited here.

[0078] In one embodiment, the target ion storage area is multiple, and the multiple target ion storage areas are radially arranged with the combination area connecting the manipulation area.

[0079] That is, in the quantum charge coupled device, the multiple target ion storage areas and the manipulation area are radially arranged around the combination area, for example, the multiple target ion storage areas are radially arranged on the right side of the combination area, and the manipulation area is radially arranged on the left side of the combination area, and the combination area connects the manipulation area and the multiple target ion storage areas, which is not limited here.

[0080] In one embodiment, the manipulation area is multiple, and the multiple manipulation areas are radially arranged with the target ion storage area connecting the combination area.

[0081] Each of the manipulation areas is provided with one of the synergistic cooling ion storage areas.

[0082] Each of the manipulation areas is provided with a group of target manipulation lights for performing quantum logic gate operations and a group of target readout lights for reading the quantum state.

[0083] In the quantum charge coupled device, the target ion storage area and the plurality of control areas are radially arranged around the binding area, for example, the target ion storage area is radially arranged on the right side of the binding area, and the plurality of control areas are radially arranged on the left side of the binding area. The binding area is connected to the plurality of control areas and the target ion storage area, and each control area is provided with a corresponding cooperative cooling ion storage area. In each control area, a set of target control light is arranged, which covers the control area and is used for quantum logic gate operation; and a set of target readout light is arranged, which covers the control area and is used for quantum state readout.

[0084] Figure 2 Figure 1 is a structural schematic diagram of a quantum charge coupled device according to an embodiment of the present application. As shown in Figure 1, in the quantum charge coupled device, a target ion storage area is radially arranged on the right side of a binding area, and two control areas are radially arranged on the left side of the binding area. The binding area is connected to the two control areas and the target ion storage area, and each control area is provided with a corresponding cooperative cooling ion storage area. Figure 2 The target readout light and the target control light arranged in each control area are not shown in Figure 1. Figure 2

[0085] Figure 3 Figure 2 is another structural schematic diagram of a quantum charge coupled device according to the embodiment of the present application. As shown in Figure 2, in the quantum charge coupled device, a target ion storage area is radially arranged on the right side of a binding area, and four control areas are radially arranged on the left side of the binding area. The binding area is connected to the four control areas and the target ion storage area, and each control area is provided with a corresponding cooperative cooling ion storage area. Figure 3 The target readout light and the target control light arranged in each control area are not shown in Figure 2. Figure 3

[0086] Based on the above architecture, the following describes the focusing distribution mode of the laser spot adapted to the above architecture.

[0087] In one embodiment, the target ion storage area focuses a set of the same kind of ion cooling light for cooling the stored target ions.

[0088] Each of the cooperative cooling ion storage areas respectively focuses a set of the same kind of ion cooling light for cooling the stored cooperative cooling ions.

[0089] Each of the control areas respectively focuses a set of the same kind of ion cooling light for cooling the target ions and the cooperative cooling ions.

[0090] ​​The target ion storage area is focused with a set of same-species ion cooling light for cooling the target ions stored in the target ion storage area, for reducing the probability of loss of the target ions in the target ion storage area. The same-species ion cooling light can be continuously or periodically turned on, which is not limited here.

[0091] Each of the cooperative cooling ion storage areas is respectively focused with a set of same-species ion cooling light for cooling the cooperative cooling ions stored in the cooperative cooling ion storage area, for reducing the probability of loss of the cooperative cooling ions in the cooperative cooling ion storage area. The same-species ion cooling light can be continuously or periodically turned on, which is not limited here.

[0092] Each of the manipulation areas is respectively focused with a set of same-species ion cooling light for cooling the target ions and the cooperative cooling ions. The same-species ion cooling light is turned on during the cooperative cooling process, and needs to be turned off during the manipulation and reading of the target ions. When the target ions in the manipulation area are in the quantum state maintenance, the target ions in the quantum state maintenance are transferred to the dark state by the state transfer light, at this time, the target ions do not interact with the same-species ion cooling light, so the same-species ion cooling light does not need to be turned off during the quantum state maintenance.

[0093] Because the same-species ion cooling light in the manipulation area needs to be turned off during the manipulation and reading of the target ions, the same-species ion cooling light can be set for each of the manipulation areas and the target ion storage area. The same-species ion cooling light in the target ion storage area can be always turned on or periodically turned on to cool the target ions, so as to avoid the temperature rise or loss of the target ions caused by long-time non-cooling.

[0094] Because the same-species ion cooling light in the manipulation area needs to be turned off during the manipulation and reading of the target ions, the same-species ion cooling light can be set for each of the manipulation areas and the cooperative cooling ion storage area. The same-species ion cooling light in the cooperative cooling ion storage area can be always turned on or periodically turned on to cool the cooperative cooling ions, so as to avoid the temperature rise or loss of the cooperative cooling ions caused by long-time non-cooling.

[0095] Figure 4 is a schematic diagram of a focusing distribution mode of a laser spot according to an embodiment of the present application, Figure 4 The architecture of the quantum charge coupled device shown is consistent with Figure 2 , which will not be repeated here. As Figure 4 shown, the target ion storage area is focused with a set of same-species ion cooling light; each of the cooperative cooling ion storage areas is respectively focused with a set of same-species ion cooling light; each of the manipulation areas is respectively focused with a set of same-species ion cooling light.

[0096] On the basis of the above-mentioned focusing distribution mode of the laser spot, the complexity of the laser light path system can be simplified.

[0097] In one embodiment, the same kind of ion cooling light is global cooling light, and all of the manipulation region, the cooperative cooling ion storage region and the target ion storage region are located within the light spot of the global cooling light.

[0098] The global cooling light is light covering all of the manipulation region, the cooperative cooling ion storage region and the target ion storage region. Through the global cooling light, global cooling of the cooperative cooling ion in storage, the target ion in storage, the cooperative cooling ion in cooperative cooling and the target ion in cooperative cooling can be realized, which greatly simplifies the light spot focusing setting requirement of the cooling light and the optical path complexity of laser beam splitting.

[0099] Figure 5 is a schematic diagram of another focusing distribution mode of a laser light spot provided according to Embodiment One of the present application, Figure 5 The architecture of the quantum charge coupled device shown is consistent with Figure 2 and will not be described herein again. As shown in Figure 5 The light spot of the global cooling light covers all of the manipulation region, the cooperative cooling ion storage region and the target ion storage region.

[0100] In one embodiment, the global cooling light is continuously turned on, and when the target ion in the manipulation region is in manipulation and readout, the global cooling light is turned off;

[0101] or the global cooling light is periodically turned on, and when the target ion in the manipulation region is in manipulation and readout, the global cooling light is turned off.

[0102] That is, the global cooling light is continuously or periodically turned on, and when the target ion in any manipulation region is in manipulation and readout, the global cooling light is turned off. However, when the target ion in the manipulation region is in quantum state maintenance, the global cooling light does not have to be turned off because the target ion in quantum state maintenance is transferred to a dark state by state transfer light.

[0103] In one embodiment, the manipulation region is specifically used for:

[0104] placing the cooperative cooling ion and the target ion in the same potential well for cooperative cooling, and placing the cooperative cooling ion on the side away from the combination region and the target ion on the side facing the combination region;

[0105] After the cooperative cooling is completed, the cooperative cooling ion and the target ion are separated by voltage control of the radio frequency electrode and the direct current electrode in the manipulation region, so that the separated cooperative cooling ion leaves the manipulation region and returns to the corresponding cooperative cooling ion storage region, and the separated target ion returns to the potential well of the manipulation region.

[0106] in combination with Figure 2It can be seen 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 completed by the instantaneous pulse electric field of the DC electrodes at a specific position. Usually, the DC electrodes will additionally increase the voltage by 0-5V based on the stable state (the position of the ion in the ion trap remains stable), and the voltage will last for about 0-50us. Generally, the DC electrodes for acceleration stage and position last for about 10us or less, and the DC electrodes for deceleration stage and position last for about 20us or more. Specifically, which DC electrodes and at which time point to apply the moving voltage can be obtained by simulation combined with experiments to obtain specific parameters.

[0107] To achieve synergistic cooling, the synergistic cooling ion and the target ion can be moved into the same potential well of the manipulation region according to the known manner in the prior art, and the two ions will not be misaligned, i.e. the synergistic cooling ion is located on one side of the anti-coupling region, and the target ion is located on the side facing the coupling region.

[0108] After the synergistic cooling is completed, the RF electrode voltage of the manipulation region is turned off or weakened, the potential well potential (also known as the depth of the potential well) for trapping the synergistic cooling ion and the target ion is reduced or disappears. Under the interaction of the Coulomb force between the ions, the synergistic cooling ion will spontaneously move to the side of the anti-coupling region, and the target ion will spontaneously move to the side facing the coupling region. The acceleration of the DC electrode can quickly separate the synergistic cooling ion and the target ion; then the RF electrode voltage of the manipulation region is restored, the potential well potential of the manipulation region is restored, and the separated target ion is guided back to the potential well of the manipulation region, so that the separated synergistic cooling ion returns to the synergistic cooling ion storage area far away from the coupling region.

[0109] In the above separation process, in order to reduce the moving distance of the target ion as much as possible, thereby reducing the heating effect generated by the movement of the target ion, it is most ideal that during the period when the RF electrode voltage of the manipulation region is turned off or weakened, the target ion remains unchanged at the position of the lowest potential well potential on the side facing the coupling region, and only the synergistic cooling ion is moved to reset and leave the potential well of the manipulation region.

[0110] Since the synergistic cooling ion and the target ion have been separated from each other during the manipulation stage of the target ion, there is no vibration mode coupling to transfer photon scattering noise, so the above-mentioned problem of "retro-phase noise enhancement" can be overcome.

[0111] In one embodiment, the synergistic cooling ion is moved to the manipulation region before the target ion.

[0112] That is, the cooperative cooling ions can be moved to the manipulation region before the target ions enter the manipulation region, so that the target ions can be quickly cooperatively cooled as soon as they enter the manipulation region, and the target ions can reach a manipulable state.

[0113] Based on the energy level construction and method, the following exemplary description of the actual application scenario is given:

[0114] Firstly, the two target ions are moved to two manipulation regions, at this time, the two target ions can be directly cooled by the same ion cooling light, or the two target ions can be cooled by the cooperative cooling method described above.

[0115] Then, one target ion is moved to the first manipulation region, which can be directly cooled by the same ion cooling light or cooperatively cooled. Then, the same ion cooling light is turned off (or the gap of the periodically turned-on same ion cooling light is selected), and the entangled state preparation is performed on the first manipulation region (if the cooperative cooling is needed, the cooperative cooling ion is removed first). After the entangled state preparation is completed, the two ions in the first manipulation region are stored in the dark state, at this time, the same ion cooling light can be turned on, and this time is very short, so the influence on the work of the same ion cooling light (i.e. cooling other ions) is small.

[0116] Then, one of the ions in the first manipulation region is transferred to the second manipulation region, and the above operation is repeated to make the two ions in the second manipulation region also in the entangled state and in the dark state.

[0117] When any ion in any manipulation region needs to be manipulated, the ion is left alone in the manipulation region, and then the operation is performed according to the above method of executing quantum logic gate operation.

[0118] If two ions need to be operated, the two ions are placed in the same manipulation region or different manipulation regions, and then the operation is performed according to the above method of executing quantum logic gate operation.

[0119] If three ions need to be operated, the three ions can be placed in the same manipulation region or different manipulation regions, and then the operation is performed according to the above method of executing quantum logic gate operation.

[0120] By analogy, any number of ions can be operated.

[0121] Embodiment two

[0122] The embodiment of the present application provides a same ion cooperative cooling device, which comprises the same ion cooperative cooling system provided by the present application. In practical application, it can be understood that the same ion cooperative cooling system is integrated in the same ion cooperative cooling device.

[0123] The synergetic cooling device for the same kind of ions can include, but is not limited to, various forms of computers, such as desktop computers, mainframe computers, workstations, servers, and other suitable computers.

[0124] The integration mode and connection relationship of the synergetic cooling system for the same kind of ions in the synergetic cooling device for the same kind of ions are not limited, as long as the corresponding functions of the synergetic cooling system for the same kind of ions can be realized.

[0125] Embodiment Three

[0126] Figure 6 is a flowchart of a synergetic cooling method for the same kind of ions according to Embodiment Three of the present application. The method is applied to a synergetic cooling system for the same kind of ions, which includes an ion trap chip, state transition light, and synergetic cooling light for the same kind of ions, and the ion trap chip contains target ions and synergetic cooling ions which are the same as the target ions.

[0127] As shown in Figure 6 , the method includes:

[0128] S610, under the condition that the target ions are in quantum state maintenance, the target ions are transferred to a dark state by the state transition light, so that the target ions do not interact with the synergetic cooling light for the same kind of ions.

[0129] S620, under the condition that the target ions are transferred to the dark state, the target ions and the synergetic cooling ions are simultaneously irradiated by the synergetic cooling light for the same kind of ions, so that the synergetic cooling ions interact with the synergetic cooling light for the same kind of ions and perform synergetic cooling on the target ions.

[0130] The technical solution of the embodiment of the present application transfers the target ions to a dark state under the condition that the target ions are in quantum state maintenance, so that the target ions do not interact with the synergetic cooling light for the same kind of ions; under the condition that the target ions are transferred to the dark state, the target ions and the synergetic cooling ions are simultaneously irradiated by the synergetic cooling light for the same kind of ions, so that the synergetic cooling ions interact with the synergetic cooling light for the same kind of ions and perform synergetic cooling on the target ions. In this scheme, the synergetic cooling ions will interact with the synergetic cooling light for the same kind of ions, the temperature will be reduced, and the target ions can be cooled; under the synergetic cooling of the synergetic cooling ions, the target ions will not interact with the synergetic cooling light for the same kind of ions, the synergetic cooling light for the same kind of ions will not directly affect the internal quantum state of the target ions, and will not cause the target ions to de-cohere by scattering photons.

[0131] Further, the dark state is a metastable state.

[0132] Further, the synergetic cooling ions and the target ions are both 40 Ca+ ; the same kind of ion cooling light is 4 2 S 1 / 2 and 4 2 P 1 / 2 Doppler cooling light of the transition, and the dark state is 3 2 D 5 / 2 energy level state.

[0133] Further, the same kind of ion cooling light further includes excitation light for making 40 Ca + from 3 2 D 3 / 2 transition to 4 2 P 1 / 2 .

[0134] Further, the cooperative cooling ion and the target ion are both 40 Ca + ; the same kind of ion cooling light includes light with wavelengths of 397nm and 866nm; and the wavelength of the state transfer light is 729nm.

[0135] Further, the ion trap chip is a quantum charge coupled device, and the quantum charge coupled device includes:

[0136] a target ion storage area, a control area, a combination area connecting the target ion storage area and the control area, and a cooperative cooling ion storage area arranged in line with the control area, the control area being located between the combination area and the cooperative cooling ion storage area;

[0137] the target ion storage area is configured to store the target ion and move the target ion to the control area through the combination area;

[0138] the cooperative cooling ion storage area is configured to store the cooperative cooling ion and move the cooperative cooling ion to the control area;

[0139] the control area is configured to transfer the target ion to a dark state using the state transfer light while the target ion is in a quantum state; cooperatively cool the target ion using the same kind of ion cooling light while the target ion is transferred to the dark state; move the cooperative cooling ion out of the control area after the cooperative cooling is completed; and perform a quantum logic gate operation on the target ion.

[0140] Further, the target ion storage area is a plurality of target ion storage areas, and the plurality of target ion storage areas are radially arranged and connected to the combination area.

[0141] Further, the control regions are multiple, and the multiple control regions are radially arranged with the target ion storage region and connected with the combination region.

[0142] Each of the control regions is provided with a cooperative cooling ion storage region.

[0143] Each of the control regions is provided with a group of target control lights for performing quantum logic gate operation and a group of target readout lights for reading quantum states.

[0144] Further, the target ion storage region is focused with a group of the same kind of ion cooling lights for cooling the stored target ions.

[0145] Each of the cooperative cooling ion storage regions is respectively focused with a group of the same kind of ion cooling lights for cooling the stored cooperative cooling ions.

[0146] Each of the control regions is respectively focused with a group of the same kind of ion cooling lights for cooling the target ions and the cooperative cooling ions.

[0147] Further, the same kind of ion cooling light is a global cooling light, and all the control regions, the cooperative cooling ion storage regions and the target ion storage region are located in the light spot of the global cooling light.

[0148] Further, the cooperative cooling ions cooperatively cool the target ions, and the cooperative cooling ions are moved out of the control region after the cooperative cooling is completed, including:

[0149] The cooperative cooling ions are cooperatively cooled with the target ions in the same potential well, and the cooperative cooling ions are located on the side away from the combination region, and the target ions are located on the side toward the combination region.

[0150] After the cooperative cooling is completed, the cooperative cooling ions and the target ions are separated by controlling the voltage of the radio frequency electrode and the direct current electrode in the control region, so that the separated cooperative cooling ions leave the control region and return to the corresponding cooperative cooling ion storage region, and the separated target ions return to the potential well of the control region.

[0151] Further, the cooperative cooling ions are moved to the control region before the target ions.

[0152] The same kind of ion cooperative cooling method and the same kind of ion cooperative cooling system provided by the embodiments of the present application have corresponding beneficial effects, which will not be repeated here.

[0153] The embodiment of the present application further provides a computer readable storage medium, which stores the isotope cooperative cooling program, and the program is executed by a processor to realize the isotope cooperative cooling method provided by the embodiment of the present application.

[0154] In the context of the present application, the computer readable storage medium can be a tangible medium, which can contain or store the isotope cooperative cooling program for use by or in connection with an instruction execution system, apparatus or device. The computer readable storage medium can include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus or device, or any suitable combination of the above. Alternatively, the computer readable storage medium can be a machine readable signal medium. More specific examples of the machine readable storage medium will include one or more lines of electrical connection, portable computer disk, hard disk, random access memory (RAM), read only memory (ROM), erasable programmable read only memory (EPROM or flash memory), optical fiber, compact disk read only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination of the above.

[0155] It should be understood that the various forms of flow shown above can be re-ordered, added to, or deleted from without departing from the scope of the present application. For example, the steps recited in the present application can be performed in parallel, in series, or in a different order, without departing from the desired results of the technical solutions of the present application, and the present application is not limited herein.

[0156] The above detailed description does not constitute a limitation on the protection scope of the present application. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modification, equivalent replacement, and improvement within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A system for synergistic cooling of isobaric ions, characterized in that, The application relates to an ion trap chip, state transition light and same-species ion cooling light, wherein target ions and cooperative cooling ions same as the target ions exist in the ion trap chip. The state transition light is used for transferring the target ions to a dark state under the condition that the target ions are in quantum state maintenance, so that the target ions do not interact with the same-species ion cooling light. The same-species ion cooling light is used for simultaneously irradiating the target ions and the cooperative cooling ions under the condition that the target ions are transferred to the dark state, so that the cooperative cooling ions interact with the same-species ion cooling light and cooperatively cool the target ions. The dark state is a metastable state.

2. The system of claim 1, wherein, The ion trap chip is a quantum charge coupled device, and the quantum charge coupled device comprises:

3. The system of claim 2, wherein, The cooperative cooling ions are the same as the target ions 40 Ca + ; the same kind of ion cooling light is the Doppler cooling light based on 4 2 S 1 / 2 and 4 2 P 1 / 2 transition, and the dark state is 3 2 D 5 / 2 energy level state.

4. The system of claim 3, wherein, The same kind of ion cooling light also includes making 40 Ca + From 3 2 D 3 / 2 Jump to 4 2 P 1 / 2 Excitation light.

5. The system of claim 2, wherein, The synergistic cooling ions are the same as the target ions 40 Ca + ; the same kind of ion cooling light includes light with wavelengths of 397 nm and 866 nm; and the wavelength of the state transfer light is 729 nm.

6. The system of claim 1, wherein, a target ion storage area, a control area, a combination area connecting the target ion storage area and the control area, and a cooperative cooling ion storage area arranged in line with the control area, wherein the control area is located between the combination area and the cooperative cooling ion storage area; the target ion storage area is used for storing the target ions and moving the target ions to the control area through the combination area; the cooperative cooling ion storage area is used for storing the cooperative cooling ions and moving the cooperative cooling ions to the control area; the control area is used for transferring the target ions to a dark state under the condition that the target ions are in quantum state maintenance by using the state transition light, cooperatively cooling the target ions by the cooperative cooling ions under the condition that the target ions are transferred to the dark state by using the same-species ion cooling light, moving the cooperative cooling ions out of the control area after the cooperative cooling is completed, and then performing quantum logic gate operation on the target ions. The target ion storage area is multiple, and the multiple target ion storage areas are radially arranged and connected to the combination area.

7. The system of claim 6, wherein, The control area is multiple, and the multiple control areas are radially arranged and connected to the target ion storage area; 8. The system of claim 6, wherein, each control area is provided with one cooperative cooling ion storage area; each control area is provided with a group of target control light used for performing quantum logic gate operation and a group of target readout light used for reading quantum state. The target ion storage area is focused with a group of same-species ion cooling light used for cooling the stored target ions; 9. The system of claim 8, wherein, each cooperative cooling ion storage area is respectively focused with a group of same-species ion cooling light used for cooling the stored cooperative cooling ions; each control area is respectively focused with a group of same-species ion cooling light used for cooling target ions and cooperative cooling ions. The same-species ion cooling light is global cooling light, and all the control areas, the cooperative cooling ion storage areas and the target ion storage areas are located in the light spot of the global cooling light.

10. The system of claim 8, wherein, The control area is specifically used for:

11. The system of claim 6, wherein, cooperatively cooling the cooperative cooling ions and the target ions in the same potential well, and the cooperative cooling ions are located on the side away from the combination area, and the target ions are located on the side facing the combination area. ​ After the collaborative cooling is completed, the collaborative cooling ions are separated from the target ions by voltage control of the radio frequency electrodes and the direct current electrodes in the manipulation region, so that the separated collaborative cooling ions leave the manipulation region and return to the corresponding collaborative cooling ion storage region, and the separated target ions return to the potential well in the manipulation region.

12. The system of claim 6, wherein, The collaborative cooling ions are moved to the manipulation region before the target ions.

13. A synergistic cooling device of homologous ions, characterized by, The system of any one of claims 1-12.

14. A method of synergistic cooling of homologous ions, characterized by, A collaborative cooling system applied to the same kind of ions, the system comprising an ion trap chip, state transfer light and same kind of ion cooling light, the ion trap chip containing target ions and collaborative cooling ions which are the same as the target ions; the method comprising: By the state transfer light, the target ions are transferred to a dark state under the condition that the target ions are in quantum state maintenance, so that the target ions do not interact with the same kind of ion cooling light; By the same kind of ion cooling light, the target ions and the collaborative cooling ions are simultaneously irradiated under the condition that the target ions are transferred to a dark state, so that the collaborative cooling ions interact with the same kind of ion cooling light and collaboratively cool the target ions.

15. A computer-readable storage medium, characterized in that, A collaborative cooling program of the same kind of ions is stored thereon, and the program is executed by a processor to implement the method of claim 14.

Images