Atom loading device, quantum system and method

Abstract

The application provides an atomic loading device, a quantum system and a method. By turning off a pushing light unit during wide linewidth cooling or narrow linewidth cooling, hot atoms in a 2D MOT cavity cannot be pushed into a 3D MOT cavity, so that the hot atoms cannot collide with atoms cooled by wide linewidth cooling in the 3D MOT cavity, and the atoms cooled preliminarily are damaged. In this case, pushing light generated by the pushing light unit cannot enter the 3D MOT cavity, and the atoms cooled preliminarily and narrow linewidth cooling are not affected. By turning on the pushing light unit when the cold atoms cooled by wide linewidth cooling and narrow linewidth cooling leave the 3D MOT cavity or are transported to a science cavity, the hot atoms in the 2D MOT cavity can be pushed into the 3D MOT cavity when quantum operation is performed in the science cavity, so that cold atom preparation in the 3D MOT cavity is carried out in parallel, and continuous or quasi-continuous loading of atoms is realized, continuous replenishment of quantum bits is realized at the system level, and macroscopic quantum dead time is reduced.

Description

Technical Field

[0001] This application relates to the fields of neutral atom quantum computing and quantum simulation technology, and more specifically, to an atom loading device and a quantum system. Background Technology

[0002] In the field of neutral atom quantum computing and quantum simulation, scaling up the system (e.g., the number of qubits) and improving computational coherence are the core challenges. Because quantum gate operations, readouts, and collisions with the vacuum background gas can lead to the loss of atoms, the system must be reloaded with cold atoms to replenish the qubits. Related technologies typically employ a single-chamber pulse loading scheme, which suffers from extremely long dead time, severely limiting the operational depth of quantum algorithms. Summary of the Invention

[0003] To address the aforementioned issues, embodiments of this application provide an atomic loading device, a quantum system, and a method.

[0004] In a first aspect, embodiments of this application provide an atomic loading device, comprising: A two-dimensional magneto-optical trap (2D MOT cavity) is used to receive thermal atoms; The push light unit and the three-dimensional magneto-optical trap 3D MOT cavity are respectively set on both sides of the 2D MOT cavity. The push light unit is used to push the hot atoms entering the 2D MOT cavity to the 3D MOT cavity. The 3D MOT cavity is used to perform wide-linewidth cooling and narrow-linewidth cooling on the entering atoms to obtain cold atoms. The scientific cavity connected to the 3D MOT cavity; Loading unit for transporting cold atoms from the 3D MOT cavity to the science cavity; The push light unit is also used to turn off after wide-linewidth cooling or narrow-linewidth cooling, and to turn on when cold atoms leave the 3D MOT cavity or when cold atoms are transported to the science cavity.

[0005] In one possible implementation, the atom loading device also includes an atom source connected to the 2D MOT cavity, the atom source being used to generate a thermal atom beam; The atomic source and the center of the 2D MOT cavity are located in the first plane, while the centers of the push light unit, the 2D MOT cavity, the 3D MOT cavity, and the scientific cavity are located in the second plane. The first plane and the second plane are perpendicular.

[0006] In one possible implementation, the loading unit includes: Two opposing Bessel laser modules are used to generate two opposing Bessel beams. The two Bessel beams interfere in the diffraction-free propagation region to form a one-dimensional moving optical lattice. The one-dimensional moving optical lattice is used to transport cold atoms from the 3D MOT cavity to the scientific cavity.

[0007] In one possible implementation, one of the Bessel laser modules is disposed on the outside of the scientific cavity opposite to the 3D MOT cavity, and the other Bessel laser module is disposed on the outside of the 3D MOT cavity opposite to the scientific cavity.

[0008] In one possible implementation, the Bessel laser module includes: Fiber optic collimators are used to convert incident light into Gaussian parallel light. A conical lens is used to refract Gaussian parallel light incident through the plane side, so that the Gaussian parallel light exits from the conical side of the lens to form a Bessel beam.

[0009] In one possible implementation, the cone lens is a fused silica cone lens with a base angle of 0.5 degrees.

[0010] In one possible implementation, the incident beam of the conical lens has a beam waist radius greater than or equal to 1.5 mm and less than or equal to 2.5 mm.

[0011] In one possible implementation, the atoms are ytterbium atoms, and the wavelength of the incident beam from the conical lens is 532 nanometers (nm); or, the atoms are strontium atoms, and the wavelength of the incident beam from the conical lens is 813 nm.

[0012] In one possible implementation, the Bessel laser module is a spatial light modulator used to modulate the incident Gaussian beam into a zero-order or higher-order Bessel beam according to a holographic phase diagram.

[0013] In one possible implementation, the atom loading device further includes: The control unit controls the frequency difference between the two Bessel laser modules, driving the one-dimensional moving optical lattice to move from the 3D MOT cavity to the scientific cavity at a first velocity and a first acceleration.

[0014] Secondly, embodiments of this application provide a quantum system, including the atom loading device provided in embodiments of this application.

[0015] Thirdly, embodiments of this application provide an atom loading method applied to an atom loading device. The atom loading device includes a 2D MOT cavity for receiving thermal atoms, push-light units respectively disposed on both sides of the 2D MOT cavity, a 3D MOT cavity, and a scientific cavity connected to the 3D MOT cavity. The push-light units are used to push thermal atoms entering the 2D MOT cavity to the 3D MOT cavity. The method includes: Atoms entering the 3D MOT cavity are subjected to wide-linewidth cooling and narrow-linewidth cooling to obtain cold atoms; Transporting cold atoms from the 3D MOT cavity to the scientific cavity; The push light unit is turned off after wide-linewidth cooling or during narrow-linewidth cooling; and the push light unit is turned on when cold atoms leave the 3DMOT cavity or when cold atoms are transported to the science cavity.

[0016] In one possible implementation, transporting cold atoms from a 3D MOT cavity to a scientific cavity includes: Two beams of Bessel light propagating in opposite directions are generated. The two beams of Bessel light interfere in the diffraction-free propagation region to form a one-dimensional moving optical lattice, which is used to load cold atoms. Controlling the movement of a one-dimensional moving optical lattice from a 3D MOT cavity to a scientific cavity.

[0017] In one possible implementation, controlling the movement of a one-dimensional moving optical lattice from a 3D MOT cavity to a scientific cavity includes: By controlling the frequency difference between two Bessel beams, a one-dimensional moving optical lattice is driven to move from the 3DMOT cavity to the scientific cavity at a first velocity and a first acceleration.

[0018] In one possible implementation, the atomic loading method also includes: Configure the control timing parameters of the atomic loading device, wherein the control timing parameters include at least one first parameter; Perform at least one round of iterative optimization, each round of iterative optimization being used to obtain the local optimum value of each first parameter; If the first condition is met in at least one round of iterative optimization, the current value of each first parameter is determined as the target control timing parameter; The atomic loading device is controlled according to the target control timing parameters.

[0019] In one possible implementation, the timing parameters for control also include at least one second parameter, and each iteration of optimization includes: Select a parameter to be optimized from at least one first parameter, determine an evaluation index from at least one second parameter, adjust the parameter to be optimized until the evaluation index meets the second condition, and determine the current value of the parameter to be optimized as the local optimum value of this round of optimization.

[0020] Fourthly, embodiments of this application provide an electronic device including a memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor is configured to implement the atomic loading method provided in embodiments of this application when executing the computer program.

[0021] Fifthly, embodiments of this application provide a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the atomic loading method provided in embodiments of this application.

[0022] Sixthly, embodiments of this application provide a computer program product, including a computer program that, when executed by a processor, implements the atomic loading method provided in embodiments of this application.

[0023] Compared with the prior art, the embodiments of this application have the following beneficial effects: This application provides an atom loading device, quantum system, and method. By shutting down the push-light unit after wide-linewidth cooling or during narrow-linewidth cooling, hot atoms in the 2D MOT cavity cannot be pushed into the 3D MOT cavity. This prevents collisions between hot atoms and atoms that have undergone wide-linewidth cooling in the 3D MOT cavity, thus avoiding damage to the pre-cooled atoms. In this case, the push-light generated by the push-light unit also cannot enter the 3D MOT cavity, and will not affect the pre-cooled atoms or the narrow-linewidth cooling. By restarting the push-light unit when the cold atoms that have undergone wide-linewidth and narrow-linewidth cooling leave the 3D MOT cavity or are transported to the scientific cavity, hot atoms in the 2D MOT cavity can be pushed into the 3D MOT cavity during quantum operations in the scientific cavity. This allows for parallel cold atom preparation in the 3D MOT cavity, thereby achieving continuous or quasi-continuous loading of atoms, continuous replenishment of qubits at the system level, and reducing macroscopic quantum dead time. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the planar structure of an atomic loading device provided in an embodiment of this application; Figure 2 This is a three-dimensional structural schematic diagram of an atomic loading device provided in an embodiment of this application; Figure 3 A schematic diagram illustrating the generation and interference principle of Bessel optical lattices; Figure 4a A schematic diagram of the spatial distribution of Gaussian light transmitted through a lens; Figure 4b A schematic diagram showing the spatial variation of the depth of a Gaussian optical lattice potential well. Figure 5a A schematic diagram of the spatial distribution of Bessel light transmission via a conical lens; Figure 5b A schematic diagram showing the spatial variation of the depth of the Bessel optical lattice potential well. Figure 6This is a timing diagram of an atomic loading device provided in an embodiment of this application; Figure 7 One of the flowcharts of an atomic loading method provided in this application embodiment; Figure 8 This is a second schematic flowchart of an atomic loading method provided in an embodiment of this application.

[0026] Reference numerals: 100-Atom loading device; 101-3D MOT cavity; 102-Scientific cavity; 103-Loading unit; 1031, 1032-Laser modules; 104-Pushing light unit; 105-2D MOT cavity; 106-Vacuum tube; 107-Zeeman deceleration unit; 108-Differential pumping pipe; 109-Vacuum pump; 110-Zeeman laser module; 111-Pre-cooled laser module. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0028] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0029] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. It should be clarified that the terms "center," "upper," "lower," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the figures, or the orientation or positional relationship commonly used when the product of the invention is in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed or operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, terms such as "first," "second," and "third" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0030] It should be noted that, where there is no conflict, different features in the embodiments of this application can be combined with each other.

[0031] For ease of understanding, the accompanying diagram shows the mutually orthogonal X-axis, Y-axis, and Z-axis. The direction along the X-axis is called the X-direction, the direction along the Y-axis is called the Y-direction, and the direction along the Z-axis is called the Z-direction. The Z-direction is the normal direction relative to the plane containing the X and Y directions.

[0032] Neutral atom quantum computing, or quantum simulation, is one of the important technological routes in current quantum information technology. Neutral atom quantum systems use neutral atoms as the carriers of quantum information, and the two long-lived internal energy levels of the atom represent the |0| and |1| qubits, respectively. State and |1 This type of system typically loads laser-cooled cold atoms into an optical tweezers array. The array includes multiple optical trapping sites, each used to trap a single cold atom. Each trapped cold atom constitutes a physical qubit, and the cold atoms trapped at multiple sites together form a qubit array. After forming the qubit array, the system can manipulate the optical path units to rearrange the atoms, prepare quantum states, perform quantum logic gate operations, and measure quantum states to achieve quantum computing or quantum simulation.

[0033] However, during the aforementioned quantum operations, the captured cold atoms do not always remain at their original capture sites. Factors such as quantum gate operations, state readouts, array rearrangements, and background gas collisions can all cause cold atoms to escape or be lost from the capture sites of the optical tweezers array. Once a cold atom escapes or is lost, the corresponding physical qubit becomes invalid, resulting in vacancies in the qubit array, which in turn reduces the effective scale and operational consistency of quantum computing or quantum simulation.

[0034] Therefore, neutral atom quantum systems typically require cold atom replenishment or reloading during operation to restore or maintain the integrity of the qubit array.

[0035] Related technologies typically employ a single-chamber pulse loading scheme, in which the preparation, cooling, loading, trapping, array rearrangement, and quantum operations of atoms are executed sequentially in time. In this approach, when the system needs to reload cold atoms, the quantum operation region must pause operation to wait for new atoms to complete their preparation, cooling, loading, and transport to the quantum operation region, until a qubit array is formed. This waiting time can be called system-level dead time, which is the time during which the system cannot effectively execute quantum operations due to the preparation, cooling, loading, transport, trapping, and array rearrangement of atoms. In this related scheme, system-level dead time often accounts for 60%–80% of the total cycle time, lasting 1–2 seconds.

[0036] Therefore, this application provides an atomic loading device to reduce the aforementioned system-level dead time and achieve continuous or quasi-continuous loading of atoms (also known as near-continuous loading).

[0037] It should be understood that the atoms in the embodiments of this application can be neutral atoms. Specifically, they can be alkaline earth metal atoms or alkaline earth-like metal atoms that require high-temperature heating, such as ytterbium (Yb) atoms, strontium (Sr) atoms, and lithium (Li) atoms. In practice, a thermal atomic beam can be generated by an atomic source, such as a high-temperature atomic furnace.

[0038] Please refer to Figure 1 and Figure 2 , Figure 1 This is a schematic diagram of the planar structure of another atom loading device 100 provided in an embodiment of this application. Figure 2 This is a three-dimensional structural schematic diagram of the atom loading device 100 provided in an embodiment of this application.

[0039] The atom loading device 100 includes a 3D MOT cavity 101, a scientific cavity 102, a loading unit 103, a push light unit 104, and a 2D MOT cavity 105. The 2D MOT cavity 105 is used to receive thermal atoms. The 3D MOT cavity 101 and the push light unit 104 are respectively disposed on both sides of the 2D MOT cavity 105 and are respectively connected to the 2D MOT cavity 105.

[0040] The push light unit 104 is used to push the hot atoms entering the 2D MOT cavity 105 to the 3D MOT cavity 101. The 3D MOT cavity 101 is used to perform wide-linewidth cooling and narrow-linewidth cooling on the entering atoms to obtain cold atoms.

[0041] In one possible implementation, the push light unit 104 can directly push the hot atom (e.g., referred to as the first atom) entering the 2D MOT cavity 105 into the 3D MOT cavity 101. In this case, the atom entering the 3D MOT cavity 101 is the hot atom (i.e., the first atom). In another possible implementation, the hot atom (i.e., the first atom) entering the 2D MOT cavity 105 can be pre-cooled. This pre-cooling can be achieved through... Figure 2 The multiple pre-cooled laser modules 111 shown are implemented. In this case, the atoms that enter the 3D MOT cavity 101 are atoms obtained by pre-cooling the hot atom (e.g., which can be called second atoms), which have little effect on the atoms that have undergone wide-linewidth cooling. Accordingly, the shutdown of the push light unit 104 at this time can be understood as mainly to avoid the push light from affecting the atoms that have undergone wide-linewidth cooling (e.g., which can be called third atoms) and narrow-linewidth cooling.

[0042] The scientific cavity 102 is connected to the 3D MOT cavity 101, and the loading unit 103 is used to transport cold atoms (e.g., which can be called fourth atoms) that have undergone wide linewidth cooling and narrow linewidth cooling from the 3D MOT cavity 101 to the scientific cavity 102.

[0043] The push light unit 104 can be turned off after wide-linewidth cooling or during narrow-linewidth cooling, and turned on when the cold atom leaves the 3D MOT cavity 101 or when the cold atom is transported to the science cavity 102. The cold atom here can be understood as the fourth atom mentioned above.

[0044] Optionally, the atom loading device 100 may further include an atom source (not shown) connected to the 2D MOT cavity 105, which is used to generate a hot atomic beam. Optionally, the atom source may be a high-temperature atomic furnace. In this case, a hot atomic beam enters the 2D MOT cavity 105. Furthermore, to reduce the heat in the entire chamber and maintain a high vacuum, the high-temperature atomic furnace may employ an internal heating system.

[0045] It should be noted that the connection in this embodiment can be a direct connection or an indirect connection. Atoms, atomic beams, atomic clouds, or atomic clusters can enter from one cavity into another cavity to which they are connected.

[0046] For example, the atom loading device 100 may also include a vacuum tube 106, and the 2D MOT cavity 105 is connected to the atom source through the vacuum tube 106. The atom source is located on the side of the vacuum tube 106 away from the 2D MOT cavity 105.

[0047] In this embodiment, the thermal atomic beam generated by the atomic source, after undergoing a first process, can be directly injected into the 2D MOT cavity 105 through the vacuum tube 106. In this case, the thermal atomic beam received by the 2D MOT cavity 105 (assumed to be the first thermal atomic beam) differs from the thermal atomic beam generated by the atomic source (assumed to be the second thermal atomic beam).

[0048] In this embodiment, the first process may include at least one of collimation and deceleration. Collimation can be understood as longitudinal collimation of the thermal atomic beam via a capillary tube, and deceleration can be understood as longitudinal cooling and deceleration achieved through a Zeeman laser and a Zeeman decelerator. In this case, the difference between the first and second thermal atomic beams may be reflected in at least one of the following dimensions: temperature, velocity, and whether or not collimation has been performed.

[0049] In the case where the first process includes collimation, the nozzle of the high-temperature atomic furnace can be equipped with multiple capillaries, for example, dozens, stacked in parallel. These multiple capillaries improve the collimation of the generated thermal atoms. Specifically, the thermal atoms generated by the high-temperature atomic furnace are isotropic and diffuse in all directions. The velocity direction of the thermal atoms passing through the capillaries is close to the longitudinal direction of the capillaries (e.g., only a few mrad angle), thus achieving a high degree of orientation, i.e., a collimation effect.

[0050] In cases where the first processing includes deceleration, the atom loading device 100 may further include a Zeeman deceleration unit 107 and a Zeeman laser module 110, which is disposed at a first laser window (not shown in the figure). The first laser window is used for the incident Zeeman laser (also referred to as Zeeman decelerated light) and is disposed on the side of the 2D MOT cavity 105 away from the atom source. Specifically, the first laser window and the Zeeman deceleration unit 107 are located on the same side of the 2D MOT cavity 105. The Zeeman laser incident through the first laser window gradually converges to the atom source. The Zeeman deceleration unit 107 and the Zeeman laser module 110, in conjunction with the Zeeman laser incident through the first laser window, can longitudinally cool and decelerate the hot atom beam in the vacuum tube 106. The longer the vacuum tube 106, the better the Zeeman deceleration effect.

[0051] Alternatively, in order to reduce the heat of the entire chamber and maintain a high vacuum, the Zeeman reduction unit 107 may employ an internal heating system.

[0052] In this embodiment, hot atoms and cold atoms can be relative concepts. If pre-cooling is not performed in the 2D MOT cavity 105, atoms before wide-linewidth cooling and narrow-linewidth cooling can be called hot atoms, and atoms after wide-linewidth cooling and narrow-linewidth cooling can be called cold atoms. If pre-cooling is performed in the 2D MOT cavity 105, atoms before pre-cooling can be called hot atoms, and atoms after pre-cooling, first-stage cooling, and second-stage cooling can be called cold atoms.

[0053] In one example, the temperature range of the hot atomic beam generated by the high-temperature atomic furnace can be 623K to 773K, or 300°C to 500°C, for example, 400°C.

[0054] The temperature of an atom is directly proportional to its thermal velocity. The Zeeman decelerator primarily affects the longitudinal velocity component of the hot atoms in the hot atom beam, while its influence on the transverse velocity component is negligible. For example, the longitudinal velocity of hot atoms generated in a nuclear furnace is approximately 390 m / s; after Zeeman deceleration, its longitudinal velocity is approximately 20 m / s. Reflected in the atomic temperature, the actual thermal temperature of the atom remains essentially unchanged after Zeeman deceleration.

[0055] In experimental characterization, the effective longitudinal temperature is typically defined using an equivalent method based on the broadening of the longitudinal velocity distribution of the atomic beam, thus characterizing the width of the kinetic energy distribution of atoms in the propagation direction. Under this equivalent definition, the effective longitudinal temperature range for an atomic beam after Zeeman deceleration can be 0.1K to 1K.

[0056] Atoms cooled with a wide linewidth can reach a temperature range of 1 mK to 5 mK, while atoms cooled with a narrow linewidth can reach a temperature range of 5 mK. K~20 K (e.g., 10) K).

[0057] In this embodiment, the push light unit 104 may have a switch, which can be used to turn the push light unit 104 on or off. It is understood that when the push light unit 104 is on, atoms in the 2D MOT cavity 105 can be pushed into the 3D MOT cavity 101, and push light is also allowed to enter the 3D MOT cavity 101; when the push light unit 104 is off, atoms in the 2D MOT cavity 105 cannot enter the 3D MOT cavity 101, and push light also cannot enter the 3D MOT cavity 101.

[0058] In this embodiment, the push light unit 104 can be turned off during narrow linewidth cooling. It should be understood that when "turn off" is understood as a shutdown action, "narrow linewidth cooling" can be understood as the start of narrow linewidth cooling; when "turn off" is understood as a shutdown state, "narrow linewidth cooling" can be understood as the period of narrow linewidth cooling.

[0059] In other words, during narrow-linewidth cooling, the push light unit 104 is in the off state (or its switch is in the off state). Optionally, the push light unit 104 may also be in the off state during the transport of cold atoms from the 3D MOT cavity 101 to the scientific cavity 102. During other periods of operation of the atom loading device 100, the push light unit 104 is in the on state (or its switch is in the on state).

[0060] One cycle of operation here can be understood as the process by which the atom loading device 100 prepares and transports a batch of cold atoms, that is, from the generation of a hot atom beam from the atom source to the corresponding batch of cold atoms being transported to the scientific cavity 102 and handed over to the crossed dipole traps (see description below). Other time periods can be understood as the time periods in one cycle other than the time period when the push light unit 104 is in the off state (such as the first time period) (such as the second time period).

[0061] The atom loading device 100 provided in this embodiment, by spatially decoupling the atom preparation region (i.e., the atom source), the cooling region (i.e., the 3D MOT cavity 101 and the 2D MOT cavity 105), and the quantum operation region (i.e., the scientific cavity 102), controls the switching unit of the push light unit 104 to turn off after wide-linewidth cooling or at the start of narrow-linewidth cooling, and to turn it back on when the cold atoms that have undergone wide-linewidth and narrow-linewidth cooling leave the cooling region or are transported to the quantum operation region. This can block hot atoms and push light during narrow-linewidth cooling, avoiding their continuous interference with the initially cooled atoms (i.e., atoms that have undergone wide-linewidth cooling) in the 3D MOT cavity 101, thereby enabling the acquisition of cold atoms suitable for subsequent loading and transport through deep cooling. At the same time, the quantum operation region can continuously perform quantum operations, while the atom preparation region and the cooling region simultaneously carry out the preparation and cooling of the next batch of cold atoms, making the atom preparation process and the quantum operation process form a parallel pipeline. This enables continuous or quasi-continuous loading of cold atoms and continuous replenishment of qubits at the system level, thereby significantly reducing system-level dead time caused by atom preparation, cooling, loading, and transportation.

[0062] It should be noted that the temperature of the atomic cloud after wide-linewidth cooling is around 2mK. If we wait 10ms, the atomic cloud will expand from 1mm to 7mm. If the high-temperature hot atomic beam is not blocked in time, it will have a significant impact on the atomic cloud subsequently cooled by the 556nm narrow-linewidth laser. Therefore, turning off the push beam unit after wide-linewidth cooling can prevent the hot atomic beam from damaging the initially cooled atoms.

[0063] Optionally, in this embodiment, the response speed of the switching unit of the push light unit 104 can be at the sub-millisecond level, that is, the switching time between turning on and off is less than 1ms.

[0064] In this embodiment, the centers of the atomic source, 2D MOT cavity 105, vacuum tube 106, and Zeeman deceleration unit 107 are located on a first plane, while the centers of the push light unit 104, 2D MOT cavity 105, 3D MOT cavity 101, and scientific cavity 102 are located on a second plane. The first plane is perpendicular to the second plane. In the normal operating state of the atomic loading device 100, the second plane can be a horizontal plane, such as... Figure 1 The XY plane is shown.

[0065] In this embodiment, both the 2D MOT cavity 105 and the 3D MOT cavity 101 are vacuum environments. The scientific cavity 102 has an extremely high vacuum level and is used to receive cold atoms transported from the loading unit 103, and to perform quantum operations using these cold atoms as qubit carriers. The quantum operations include at least one of qubit storage, array rearrangement, and logic gate operations. Optionally, the vacuum environment within the atom loading device 100 can be achieved using a vacuum pump 109.

[0066] At the scientific cavity, cold atoms can be captured using two intersecting dipole traps for storage in an atom library for quantum computing or quantum simulation. Specifically, the push-light unit 104 can be restarted when the loading unit 103 completes the handover by sending the previous batch of cold atoms (i.e., cold atoms cooled by both wide and narrow linewidths) into the scientific cavity 102. This handover can be understood as the cold atoms transported to the scientific cavity being captured by the intersecting dipole traps. At this point, the cooling and capture of the next batch of cold atoms can begin within the 3D MOT cavity 101, achieving continuous or quasi-continuous loading at the system level.

[0067] The aforementioned wide-linewidth and narrow-linewidth cooling can be achieved using a three-dimensional cooling laser device and a magnetic field coil (not shown in the figure). This magnetic field coil can be a pair of anti-Helmholtz coils, with water flowing through its center for cooling. Optionally, the three-dimensional cooling laser device and magnetic field coil can be turned on in advance to allow for timely wide-linewidth cooling when hot atoms enter the 3D MOT cavity 101. This advance activation can occur before the atomic source is turned on or before the hot atomic beam is generated.

[0068] In this embodiment, taking ytterbium atoms as an example, a 399 nm wavelength laser can be used for wide-linewidth cooling, and a 556 nm wavelength laser can be used for narrow-linewidth cooling. Similarly, for strontium atoms (such as strontium-87), a 461 nm wavelength laser can be used for wide-linewidth cooling, and a 689 nm wavelength laser can be used for narrow-linewidth cooling. This embodiment does not impose any limitations on these aspects.

[0069] It should be understood that the aforementioned three-dimensional cooling laser device and magnetic field coil may be part of the atom loading device 100 or independent of the atom loading device 100, and the embodiments of this application do not limit this.

[0070] Optionally, the loading unit 103 may include two laser modules 1031 and 1032 arranged opposite to each other, wherein laser module 1031 is disposed on the side of the 3D MOT cavity 101 opposite to the scientific cavity 102, and laser module 1032 is disposed on the side of the scientific cavity 102 opposite to the 3D MOT cavity 101. Here, the laser module can also be understood as a laser generating unit.

[0071] Optionally, both laser modules 1031 and 1032 can be Bessel laser modules. The two Bessel laser modules are used to generate two opposing Bessel beams. Please refer to... Figure 3Two Bessel beams have a diffraction-free propagation region (also called a non-diffraction region). The two Bessel beams can interfere to form a one-dimensional optical lattice within the overlapping region of their diffraction-free propagation regions. This overlapping region covers the center of the 3D MOT cavity 101 and extends to the center of the scientific cavity 102. This one-dimensional optical lattice is used to load (or trap) cold atoms that have undergone wide-linewidth cooling and narrow-linewidth cooling.

[0072] By controlling the frequency difference between the two Bessel laser modules, a one-dimensional optical lattice can be driven to move at a first velocity and a first acceleration. Therefore, this one-dimensional optical lattice can also be referred to as a one-dimensional moving optical lattice in this embodiment. By controlling the movement of the one-dimensional optical lattice, that is, through this one-dimensional moving optical lattice, cold atoms that have undergone wide-linewidth cooling and narrow-linewidth cooling can be transported from the 3D MOT cavity 101 to the scientific cavity 102. It should be noted that the one-dimensional optical lattice moves from the 3D MOT cavity 101 along the uniaxial scientific cavity 102.

[0073] Optionally, the atom loading device 100 may also include a control unit (not shown in the figure) which can control the frequency difference between the two Bessel laser modules.

[0074] Please refer to Figure 4a , Figure 4b , Figure 5a and Figure 5b , Figure 4a This shows the spatial distribution of Gaussian light transmitted through the lens. Figure 4b This shows the variation of the Gaussian optical lattice potential well depth with space; Figure 5a The spatial distribution of Bessel light transmission via a conical lens is shown (including the central non-diffractive main lobe). Figure 5b The variation of the Bessel optical lattice potential well depth with space is shown.

[0075] In related technologies, Gaussian beams are typically used to construct optical lattices for the transcavity transport of atoms. However, the distance between the 3D MOT cavity and the scientific cavity is relatively long (e.g., up to 34 cm). Due to the Rayleigh length limitation, the Gaussian beam undergoes significant diffraction divergence during long-distance transport, resulting in uneven optical dipole well depths experienced by the atoms, which easily leads to atom heating and mid-transmission loss. In the embodiments of this application, because the optical lattice formed by the Bessel beam has the physical properties of no diffraction and self-healing, it can maintain a very small and constant central spot during uniaxial transcavity transport of tens of centimeters. This allows atoms to experience a uniform potential well depth throughout long-distance transport, thus solving the problem of atom heating and loss caused by Gaussian beam divergence.

[0076] During implementation, the control unit can fix the frequency of one Bessel laser module and change or adjust the frequency of the other Bessel laser module to control the frequency difference between the two Bessel laser modules. Optionally, the relative frequency difference between the two Bessel laser modules can reach up to 1.88 MHz.

[0077] Optionally, when controlling the movement of the one-dimensional optical lattice, an "asymmetric" acceleration sweep curve can be used, that is, controlling the initial starting acceleration of the one-dimensional optical lattice to be approximately 10g (g represents gravitational acceleration) and the final deceleration acceleration to be approximately 5g. In this way, the lattice potential trap can be tilted during the acceleration and deceleration phases, spontaneously forming an active overflow mechanism, that is, actively eliminating high-kinetic-energy hot atoms, so that the atoms, atomic clouds, or atomic clusters remain at a low temperature when they arrive at the scientific cavity 102.

[0078] In this application embodiment, the Bessel laser module can be implemented in several different ways. In one example, the Bessel laser module may include an fiber collimator and an axicon lens. The fiber collimator is used to convert the incident light into Gaussian parallel light. During optical path installation, a planar incident and conical exit configuration can be adopted. That is, the Gaussian parallel light output from the fiber collimator is incident through the planar side of the axicon lens, refracted by the axicon lens, and exits from the conical side. This completely eliminates the ghost focus caused by total internal reflection of high-power (e.g., greater than 7 watts) laser light on the inner surface of the lens, avoiding optical field distortion and preventing thermal breakdown damage to the lens due to excessive local temperature rise under high-power laser light.

[0079] The conical lens can be a fused silica conical lens with a base angle of 0.5° to maintain a constant main lobe radius (approximately 50) at the center of the Bessel beam. It should be understood that the 0.5° here is for illustrative purposes only, and the bottom angle of the conical lens can also be other values ​​as needed, such as 1°. This embodiment does not limit this.

[0080] Furthermore, the beam waist radius of the incident beam of the conical lens can be greater than or equal to 1.5 mm and less than or equal to 2.5 mm.

[0081] In the case where the atom in this application embodiment is a strontium atom, the wavelength of the incident light from the conical lens can be 813 nm (i.e., the magic wavelength of a strontium atom).

[0082] In the embodiment of this application, where the atoms are ytterbium atoms, the incident beam of the conical lens can be a conventional far-detuned 1064nm laser. In this case, the one-dimensional optical lattice can achieve a stable movement of up to 1.0 m / s within the vacuum cavity. Alternatively, the incident beam of the conical lens can be a near-resonant 532nm continuous laser. In this case, the one-dimensional optical lattice can achieve a stable movement of up to 0.5 m / s within the vacuum cavity. Using a 532nm laser can save laser power and reduce the heat generated by the laser. Furthermore, since the 532nm laser is visible to the naked eye, its propagation path can be directly observed, facilitating coaxial alignment and real-time adjustment of the bidirectional optical path within the narrow differential pumping pipe 108 between the 3D MOT cavity 101 and the scientific cavity 102, thereby improving optical path alignment accuracy and system stability.

[0083] The following example, using a 532nm laser to transmit ytterbium-171 atoms, further illustrates the technical effects of the above parameter settings for the Bessel laser module.

[0084] Incident laser wavelength It's 532nm, and the refractive index n of fused silica at this wavelength is approximately 1.46. If a bottom angle is used... For a conical lens with an angle of 0.5°, under the paraxial approximation, the exit deflection angle is... Approximately That is, approximately 0.004 rad.

[0085] Under the above conditions, the radius of the central non-diffraction main lobe is... The constancy is verified as follows: According to the formula for the radial intensity distribution of a zero-order Bessel beam, the radius of the central main lobe is determined by the following formula: (1) As can be seen, the above calculation results are consistent with the set target (approximately 50). The dimensions are highly compatible. This size provides sufficient and uniform lateral confinement space for cold atoms during long-distance transport across chambers.

[0086] For no diffraction distance The verification of doubling and optimizing the light transmission aperture is as follows: The maximum axial length (i.e., the non-diffraction distance) of the Bessel interference overlap region is determined by the beam waist radius of the incident Gaussian beam. Decide: .

[0087] Compared to a traditional lens with a base angle of 1°, the lens with a small base angle of 0.5° in this embodiment of the application can achieve the following technical effects: 1) If the waist radius of the incident beam The thickness is 2.0mm, which is suitable for a 1° bottom angle lens. However, it cannot cover the entire cross-chamber distance; while using the 0.5° bottom-angle lens of this application embodiment, This covers and exceeds the physical length requirements of the differential evacuation duct 108 between the 3DMOT cavity 101 and the scientific cavity 102. Therefore, using a 0.5° small bottom-angle lens can double the diffraction-free distance of the Bessel beam.

[0088] 2) To achieve the target transmission distance (e.g., 35cm), using a 0.5° bottom-angle lens only requires reducing the beam waist radius of the incident Gaussian beam to... mm. This allows for the use of miniature optical adjustment mounts with a diameter of 0.5 inches or smaller, significantly improving the compactness of the optical path system and its resistance to mechanical vibration.

[0089] It should be understood that the above explanation uses ytterbium as an example, but its verification logic also applies to other atoms, such as strontium and lithium (Li).

[0090] Based on the above, using a 0.5° small bottom angle lens can not only double the diffraction-free distance of the Bessel beam, but also allow the use of smaller aperture optical elements.

[0091] Through the above design of the embodiments of this application, for ytterbium atoms, a conical lens with a base angle of 0.5° is used in combination with a 532nm near-resonant continuous laser. The incident Gaussian beam waist radius is 1.5mm~2.5mm. At this time, the diffraction-free distance of the Bessel beam can reach 40cm~60cm, which can completely cover and exceed the physical transmission distance between the 3D MOT cavity and the scientific cavity (usually 30cm~35cm). This ensures that the atoms are in a uniform potential well throughout the transportation process and are not easily lost. The transmission efficiency is expected to jump from 30%~40% of the traditional Gaussian beam scheme to 80%~90%.

[0092] In another example, the Bessel laser module can be implemented using a spatial light modulator, which can modulate the incident Gaussian beam into a zero-order or higher-order Bessel beam based on the input holographic phase diagram. This approach is suitable for quantum simulation experiments requiring extremely high degrees of freedom of manipulation.

[0093] In implementation, the static conical lens in the aforementioned method can be eliminated, and a phase-only spatial light modulator (SLM) can be placed at the front end of the 4f relay imaging system. During operation, the control unit inputs a holographic phase map (which can be a computed holographic phase map, such as a conical phase map with an added spiral phase) to the SLM, directly modulating the incident Gaussian beam into a zero-order or higher-order (with orbital angular momentum) Bessel beam. During transmission, by dynamically refreshing the phase map on the SLM, the axial starting position and spot size of the diffraction-free focal length (Bessel zone) can be finely adjusted in real time without moving any mechanical components.

[0094] By employing the aforementioned spatial light modulator, on the one hand, aberrations caused by the glass window of the ultra-high vacuum cavity can be accurately compensated; on the other hand, the high-order Bessel beam (hollow beam) generated by the spatial light modulator can be used to construct an optical channel that generates blue detuning (repulsion) confinement of atoms, further reducing the photon scattering heating rate of atoms during transmission.

[0095] To enable those skilled in the art to better understand this solution, the working process of the atomic loading device 100 provided in the embodiments of this application will be described.

[0096] Taking ytterbium atoms as an example, the atom loading device 100 provided in this application embodiment can operate according to the following process: Step 1: Turn on the wide-linewidth cooling laser and magnetic field coil.

[0097] Step 2: The control unit turns on the push light unit (i.e., the push light unit is in the ON state). The hot atom beam, which has been heated at high temperature in the atom source, is ejected along the Z direction and enters the 2D MOT cavity. Then it enters the Zeeman deceleration unit and is decelerated by the Zeeman deceleration laser incident from the first laser inlet. The decelerated hot atoms are pushed into the 3D MOT cavity by the push light unit. A 399nm wide-linewidth cooling laser and magnetic field coil are used to perform wide-linewidth cooling on the hot atoms entering the 3D MOT cavity, capturing a large number of atoms at the center of the 3D MOT cavity.

[0098] Step 2 here is the initial capture phase, referred to as phase A in this example.

[0099] For example, if it is strontium atoms, a 461 nm wide linewidth cooling laser can be used in stage A.

[0100] Step 3: After Phase A is completed, the control unit sends a trigger signal, pushing the optical unit to shut down (i.e., switch to OFF state) within less than 1ms, completely physically cutting off subsequent hot atoms, thereby minimizing the background gas pressure and light scattering noise in the 3D MOT cavity. Under this ultra-high vacuum environment, a 556nm narrow-linewidth cooling laser is immediately activated to perform narrow-linewidth cooling on the captured atoms, thereby further cooling the captured atoms to extremely low temperatures.

[0101] Step 3 here is the cut-off and cooling stage, referred to as stage B in this example.

[0102] For example, if it is strontium atoms, a narrow linewidth cooling laser of 689 nm can be used in stage B.

[0103] Step 4: After stage B, the magnetic field of the 3D MOT cavity is turned off, and the two opposing Bessel laser modules (i.e., Bessel beam generating units) are turned on to generate two Bessel laser beams along the -Y and Y directions. These two Bessel laser beams are 532nm near-resonant continuous lasers, which can interfere to form a one-dimensional optical lattice in the diffraction-free propagation region. This one-dimensional optical lattice is used to load cooled atomic clusters (the atoms of which are cold atoms that have undergone wide-linewidth cooling and narrow-linewidth cooling). The frequency difference between the two opposing Bessel beams is adjusted by an acousto-optic modulator (AOM) so that the one-dimensional optical lattice and its loaded cold atomic clusters move along a single axis (e.g., ...) with constant acceleration and velocity. Figure 1 The cold atoms (shown on the Y-axis) move towards the scientific cavity, smoothly and without diffraction passing through the differential pumping pipe into the scientific cavity, and are unloaded in the cross optical dipole trap (ODT).

[0104] Step 4 here is the lossless transmission stage, which can be called stage C in this example.

[0105] For example, if it is strontium atoms, an 813nm laser can be used as the incident light in stage C to form a Bessel beam.

[0106] Step 5: After stage C ends, the control unit restarts the push light unit, and the atomic loading device repeats this process (referred to as stage D in this example, i.e., the loop stage), thereby achieving quasi-continuous atomic loading and pipeline operation with no dead time on a macroscopic level.

[0107] Please refer to Figure 6 , Figure 6 This diagram illustrates the timing relationship between the on / off states of each module / device in the atomic loading apparatus during the above workflow. The horizontal axis represents time, and the vertical axis represents the on / off state of each module / device. It can be understood that... Figure 6 The timing relationship shown represents the scenario where the push light unit is activated when cold atoms are transported to the scientific cavity.

[0108] When the horizontal axis is in stage A, the push light unit is in the on state, the wide linewidth cooling laser (such as 399nm cooling laser, 461nm cooling laser) and Zeeman deceleration light are in the on state, the narrow linewidth cooling laser (such as 556nm cooling laser, 689nm cooling laser) is in the off state, and the Bessel laser module is in the off state (which can also be understood as the Bessel optical lattice not being used).

[0109] When enough atoms are captured within the 3D MOT cavity, stage B begins. At this point, the push beam unit is turned off, the wide-linewidth cooling laser is turned off, and the narrow-linewidth cooling laser is turned on; the Bessel laser module remains off.

[0110] When the atoms are cooled to a sufficiently low temperature, they enter stage C. At this point, the Bessel laser module is activated, and the frequency difference pulling of the Bessel laser module is initiated, causing the one-dimensional optical lattice to move along... Figure 1 The scientific cavity in the Y direction is smoothly shifted as shown.

[0111] When the one-dimensional optical lattice transports cold atoms to the scientific cavity and transfers them to the cross optical dipole trap, the push optical unit is restarted, entering stage D, which repeats the aforementioned stages A, B, and C.

[0112] The atom loading device 100 provided in this application transmits cold atoms through a high-speed, diffraction-free Bessel optical lattice. Using a 1064nm laser as the incident light for the conical lens, the time for a single cross-cavity transmission can be strictly controlled within 350ms. Combined with a push-light unit (with a response time in the sub-millisecond range), while the scientific cavity performs quantum gate operations and array rearrangement, the 3D MOT can simultaneously prepare the next batch of subqubits. Spatial decoupling and temporal pipeline design significantly compress the quantum dead time of traditional single-cavity systems from several seconds to 1 / 5 or even less of the original time. Theoretically, the dead time is only limited by the short-range handover and array rearrangement time of the first one-dimensional optical lattice (in the hundreds of milliseconds). Once continuous transmission begins, a continuous supply of atoms can be replenished.

[0113] This application also provides a quantum system including the atom loading device provided in this application. Furthermore, the quantum system may also include an optical path module, by which quantum manipulations can be performed within a scientific cavity.

[0114] Alternatively, the quantum system may be an optical clock, a quantum computing system, or a quantum simulation system. This application does not limit this aspect.

[0115] This application also provides an atomic loading method, implemented based on the atomic loading apparatus provided in this application. Please refer to... Figure 7 The implementation process of this atomic loading method is as follows.

[0116] S110 performs wide-linewidth and narrow-linewidth cooling on atoms entering the 3D MOT cavity to obtain cold atoms.

[0117] Reference Figure 2 In one possible embodiment of the atom loading device 100 shown, hot atoms generated by the atom source are decelerated by Zeeman in the vacuum tube 106 and then enter the 2D MOT cavity 105, where they are directly propelled from the 2D MOT cavity 105 into the 3D MOT cavity 101 by a pusher light. In another possible embodiment, the atoms in the 2D MOT cavity 105 may be pre-cooled before being propelled into the 3D MOT cavity 101 by the pusher light.

[0118] S120 transports cold atoms from the 3D MOT cavity to the science cavity.

[0119] In this embodiment, S110 is completed within the 3D MOT cavity, and S120 is completed by the loading unit. For details of its implementation, please refer to the description of the atomic loading device 100 above, which will not be repeated here.

[0120] S130, shuts down the push light unit after wide-linewidth cooling or during narrow-linewidth cooling.

[0121] S140 activates the push light unit when cold atoms leave the 3D MOT cavity or when cold atoms are transported to the science cavity.

[0122] It should be understood that the above step numbers do not represent the execution order. Referring to the description of the atom loading apparatus 100 in the above embodiments, it can be seen that S130 can be performed during narrow-linewidth cooling (part of S110) and during the execution of S120. Assuming that S130 is performed in the first time period, then S140 is performed in a second time period, excluding the first time period, within the time period of each batch of cold atom preparation and transport (i.e., from the generation of a hot atom beam in the atomic furnace to the transport of the corresponding cold atoms to the scientific cavity and their transfer to the cross-dipole trap).

[0123] In this embodiment, S120 can be implemented by a loading unit, specifically by two Bessel laser modules included in the loading unit. In this case, S120 may include the following sub-steps: S121 generates two opposing Bessel beams that interfere to form a one-dimensional moving optical lattice in a diffraction-free propagation region. The one-dimensional moving optical lattice is used to load cold atoms that have undergone wide-linewidth cooling and narrow-linewidth cooling.

[0124] S122, control the one-dimensional moving optical lattice to move from the 3D MOT cavity to the scientific cavity.

[0125] S122 may further include the following sub-steps: By controlling the frequency difference between the two Bessel beams, a one-dimensional moving optical lattice is made to move from the 3D MOT cavity to the scientific cavity at a first velocity and a first acceleration.

[0126] For the specific implementation of S121 and S122, please refer to the description of the loading unit 103 in the atomic loading device 100 in the above embodiments, which will not be repeated here.

[0127] It should be understood that the modules or devices involved in the above steps S110-S140 can be controlled by a control unit. This control unit can also be called a control system, for example, a control board, which stores computer programs for controlling the relevant modules or devices (such as laser modules, switching units / thermal atom beam switches, magnetic field coils, etc.) of the atom loading device to implement the above method.

[0128] In this embodiment, due to the extremely high response speed requirement, one optional approach is to control the switching unit, magnetic field coil, and each laser module to turn on or off according to a preset trigger timing sequence. This preset trigger timing sequence can be initially set as the initial sequence, and then iteratively optimized by repeatedly executing the above method or repeatedly executing stages A-C until the preset conditions are met. It should be understood that when the preset trigger timing sequence meets the preset conditions, the operation of the atom loading device 100 is consistent with that described in the foregoing embodiments of this application.

[0129] Therefore, please refer to Figure 8 The atomic loading method provided in this application embodiment may further include the following steps: S210, Configure the control timing parameters of the atom loading device, the control timing parameters including at least one first parameter; S220, perform at least one round of iterative optimization, each round of iterative optimization is used to obtain the local optimum value of each first parameter; S230, if the first condition is met in at least one round of iterative optimization, the current value of each first parameter is determined as the target control timing parameter; S240 controls the atom loading device according to the target control timing parameters.

[0130] The atomic loading device can be any atomic loading device provided in the embodiments of this application.

[0131] The first parameter is the timing parameter that needs to be optimized. Optionally, each first parameter may correspond to a module or device in the atomic loading device, and may specifically include at least one of the following: turn-on time, turn-off time, hold time, accelerated transmission time, uniform transmission time, and unloading time of the corresponding module or device.

[0132] For example, at least one of the first parameters may include, but is not limited to: the turn-on time, turn-off time, and hold time of the switching unit (such as the switching unit of the push light unit 104), the turn-on time and turn-off time of the Zeeman laser, the start time and end time of the first cooling laser, the start time and end time of the second cooling laser, and the turn-on time, turn-off time, accelerated transmission time, uniform transmission time, and unloading time of the one-dimensional optical lattice. Wherein, the first cooling laser is a cooling laser for wide-linewidth cooling (such as a wide-linewidth cooling laser), and the second cooling laser is a cooling laser for narrow-linewidth cooling (such as a narrow-linewidth cooling laser).

[0133] The action time of the one-dimensional optical lattice can also be understood as the corresponding action time of the loading unit (e.g., two Bessel laser modules). The action times of the Zeeman laser, the first cooling laser, and the second cooling laser can also be understood as the corresponding action times of the respective laser modules.

[0134] The timing parameters can also include at least one second parameter. In this case, each iteration of optimization can include: Select a parameter to be optimized from the at least one first parameter, determine an evaluation index from the at least one second parameter, adjust the parameter to be optimized until the evaluation index meets the second condition, and determine the current value of the parameter to be optimized as the local optimum value of this round of optimization.

[0135] The second parameter is a candidate indicator. At least one second parameter may include, but is not limited to: the number of atoms in the 3D MOT cavity, the cold atom temperature, the loading efficiency, the number of atoms after transmission to the scientific cavity, or the qubit replenishment efficiency.

[0136] The loading efficiency can be understood as the efficiency by which the hot atom beam, after being decelerated and transported into the 3D MOT cavity, is cooled by wide-linewidth and narrow-linewidth lasers to form cold atoms. For example, the loading efficiency can be represented by N1 / N2, where N1 is the number of successfully captured cold atoms and N2 is the number of hot atoms entering the 3D MOT cavity.

[0137] In one possible approach, the qubit replenishment efficiency can be represented by N3 / N4. N3 represents the number of qubits successfully replenished during the process of replenishing atoms from the 3D MOT cavity to the scientific cavity; N4 represents the number of qubits to be replenished. In another possible approach, the qubit replenishment efficiency can be represented as a percentage of the atom replenishment rate and the atom loss rate.

[0138] The second condition can be that further adjustment or change of the parameter to be optimized can no longer significantly improve the evaluation index. Here, "cannot significantly improve the evaluation index" can be understood as the improvement value of the parameter to be optimized after one iteration being less than the second threshold. This second threshold can be set based on experience or statistical data. This embodiment does not impose any restrictions on this.

[0139] The first condition is the condition for stopping iterative optimization. It can be that the improvement of the evaluation index is less than a first threshold in several consecutive iterations, or that the number of iterations reaches a preset number. The first threshold and the preset number of iterations can be set based on experience or statistical data, and this embodiment does not impose any restrictions on them.

[0140] Optionally, the above-mentioned S210 to S240 can be executed by a control unit, which can be regarded as part of the atomic loading device provided in the embodiments of this application, or it can be independent of the atomic loading device.

[0141] In detail, the control unit can employ open-loop control timing to improve loading efficiency. After the atomic loading device is assembled, the control unit performs multiple rounds of iterative optimization on the trigger timing (i.e., control timing) of each module / device.

[0142] The control unit selects one or a set of first parameters as the parameters to be optimized, adjusts the parameters to be optimized, and measures the corresponding evaluation index. When the current value of the evaluation index (i.e. the measurement result) meets the second condition, it can be considered that it has obtained the local optimum value of this round of optimization. Otherwise, it is necessary to continue to adjust the parameters to be optimized and measure the corresponding evaluation index.

[0143] Optionally, in the embodiments of this application, the selection of evaluation indicators may be related to the selection of parameters to be optimized in this round of optimization. For example, the closing time of the switching unit may be changed, or the opening time and holding time of the switching unit may be changed, and the number of atoms in the 3D MOT cavity or the subsequent transmission efficiency may be measured accordingly.

[0144] During the implementation process, different first parameters are selected as parameters to be optimized in sequence in the manner described above, and their local optimal values ​​are obtained until the local optimal value of each first parameter is obtained, which can be considered as completing one round of optimization.

[0145] After completing one round of optimization for each of the first parameters, the control unit can repeat the above process for iterative iteration. The condition for stopping the iteration is the first condition. This compensates for the timing coupling effect between different modules / devices, gradually obtaining the timing combination that optimally combines atomic loading efficiency, cooling efficiency, and transport efficiency. At this point, the control unit uses the current timing combination as the optimized operating timing and applies it to control the corresponding modules or devices of the atomic loading device.

[0146] This application also provides an electronic device, which may be, for example, the control unit described above. The electronic device includes one or more components: a processor, a memory, and one or more computer programs, wherein the one or more computer programs may be stored in the memory and configured to be executed by one or more processors, and the one or more computer programs are configured to perform the methods described in this application.

[0147] A processor may include one or more processing cores. The processor connects various parts of the electronic device through various interfaces and lines, and performs various functions and processes data by running or executing instructions, programs, code sets, or instruction sets stored in memory, and by calling data stored in memory. Optionally, the processor may be implemented using at least one hardware form of Digital Signal Processing (DSP), Field-Programmable Gate Array (FPGA), or Programmable Logic Array (PLA). The processor may integrate one or more of the following: Central Processing Unit (CPU), Graphics Processing Unit (GPU), and modem. The CPU primarily handles the operating system, user interface, and applications; the GPU is responsible for rendering and drawing the displayed content; and the modem handles wireless communication. It is understood that the modem may also be implemented separately as a communication chip, without being integrated into the processor.

[0148] The memory may include random access memory (RAM) or read-only memory (ROM). The memory can be used to store instructions, programs, code, code sets, or instruction sets. The memory may include a program storage area and a data storage area. The program storage area may store instructions for implementing an operating system, instructions for implementing at least one function (such as touch functionality, sound playback functionality, image playback functionality, etc.), and instructions for implementing the various method embodiments described below. The data storage area may also store data created during the use of the electronic device (e.g., first parameters, second parameters required for iterative optimization, and optimized timing combinations).

[0149] This application also provides a structural block diagram of a computer-readable storage medium. The computer-readable storage medium stores program code that can be invoked by a processor to execute the methods described in the above method embodiments. The computer-readable storage medium may be an electronic memory such as flash memory, EEPROM (Electrically Erasable Programmable Read-Only Memory), EPROM, hard disk, or ROM. Optionally, the computer-readable storage medium includes a non-transitory computer-readable storage medium. The computer-readable storage medium has storage space for program code that performs any of the method steps described above. This program code can be read from or written to one or more computer program products. The program code may be compressed, for example, in a suitable form.

[0150] This application also provides a computer program product or computer program, which includes computer instructions stored in a computer-readable storage medium. A processor of a computer device can read the computer instructions from the computer-readable storage medium and execute the computer instructions, causing the computer device to perform the atomic loading method provided in the above embodiments of this application.

[0151] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0152] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An atomic loading device, characterized in that, include: A two-dimensional magneto-optical trap (2D MOT cavity) is used to receive thermal atoms; The push light unit and the three-dimensional magneto-optical trap 3D MOT cavity are respectively arranged on both sides of the 2D MOT cavity. The push light unit is used to push the hot atoms entering the 2D MOT cavity to the 3D MOT cavity. The 3D MOT cavity is used to perform wide-linewidth cooling and narrow-linewidth cooling on the entering atoms to obtain cold atoms. The scientific cavity connected to the 3D MOT cavity; A loading unit for transporting the cold atoms from the 3D MOT cavity to the scientific cavity; The push light unit is also used to turn off after the wide linewidth is cooled or during the narrow linewidth is cooled, and to turn on when the cold atom leaves the 3D MOT cavity or when the cold atom is transported to the scientific cavity.

2. The atom loading device according to claim 1, characterized in that, The atom loading device also includes an atom source connected to the 2D MOT cavity, the atom source being used to generate a thermal atom beam; The atomic source and the center of the 2D MOT cavity are located in a first plane, and the centers of the push light unit, the 2D MOT cavity, the 3D MOT cavity, and the scientific cavity are located in a second plane. The first plane is perpendicular to the second plane.

3. The atom loading device according to claim 1 or 2, characterized in that, The loading unit includes: Two opposing Bessel laser modules are used to generate two opposing Bessel beams. The two Bessel beams interfere to form a one-dimensional moving optical lattice in a diffraction-free propagation region. The one-dimensional moving optical lattice is used to transport the cold atoms from the 3D MOT cavity to the scientific cavity.

4. The atom loading device according to claim 3, characterized in that, One of the Bessel laser modules is disposed on the outside of the scientific cavity opposite to the 3D MOT cavity, and the other Bessel laser module is disposed on the outside of the 3D MOT cavity opposite to the scientific cavity.

5. The atom loading device according to claim 3, characterized in that, The Bessel laser module includes: Fiber optic collimators are used to convert incident light into Gaussian parallel light. A conical lens is used to refract Gaussian parallel light incident through a plane side, so that the Gaussian parallel light exits from the conical side of the conical lens to form a Bessel beam.

6. The atom loading device according to claim 5, characterized in that, The conical lens is a fused silica conical lens with a base angle of 0.5 degrees.

7. The atomic loading device according to claim 6, characterized in that, The incident beam of the conical lens has a waist radius greater than or equal to 1.5 mm and less than or equal to 2.5 mm.

8. The atom loading device according to claim 5, characterized in that, The atom is a ytterbium atom, and the wavelength of the incident beam from the conical lens is 532 nanometers; or, The atom is a strontium atom, and the wavelength of the incident beam from the conical lens is 813 nanometers.

9. The atomic loading device according to claim 3, characterized in that, The Bessel laser module is a spatial light modulator, which is used to modulate the incident Gaussian beam into a zero-order or higher-order Bessel beam according to the holographic phase diagram.

10. The atom loading device according to claim 3, characterized in that, The atom loading device further includes: The control unit is used to control the frequency difference between the two Bessel laser modules and drive the one-dimensional moving optical lattice to move from the 3D MOT cavity to the scientific cavity at a first speed and a first acceleration.

11. A quantum system, characterized in that, Includes the atomic loading device as described in any one of claims 1 to 10.

12. An atomic loading method, characterized in that, An atom loading device is applied, comprising a 2D MOT cavity for receiving hot atoms, push-beam units respectively disposed on both sides of the 2D MOT cavity, a 3D MOT cavity, and a scientific cavity connected to the 3D MOT cavity. The push-beam units are used to push hot atoms entering the 2D MOT cavity to the 3D MOT cavity. The method includes: Atoms entering the 3D MOT cavity are subjected to wide-linewidth cooling and narrow-linewidth cooling to obtain cold atoms; The cold atoms are transported from the 3D MOT cavity to the scientific cavity; The push light unit is turned off after the wide linewidth cooling or during the narrow linewidth cooling; and the push light unit is turned on when the cold atom leaves the 3D MOT cavity or when the cold atom is transported to the science cavity.

13. The atomic loading method according to claim 12, characterized in that, The transport of the cold atoms from the 3DMOT cavity to the scientific cavity includes: Two beams of Bessel light propagating in opposite directions are generated. The two beams of Bessel light interfere to form a one-dimensional moving optical lattice in a diffraction-free propagation region. The one-dimensional moving optical lattice is used to load the cold atoms. The one-dimensional moving optical lattice is controlled to move from the 3D MOT cavity to the scientific cavity.

14. The atomic loading method according to claim 13, characterized in that, Controlling the movement of the one-dimensional moving optical lattice from the 3D MOT cavity to the scientific cavity includes: By controlling the frequency difference between the two Bessel beams, the one-dimensional moving optical lattice is driven to move from the 3D MOT cavity to the scientific cavity at a first velocity and a first acceleration.

15. The atomic loading method according to any one of claims 12 to 14, characterized in that, The method further includes: Configure the control timing parameters of the atomic loading device, wherein the control timing parameters include at least one first parameter; Perform at least one round of iterative optimization, each round of which is used to obtain a local optimum value for each of the first parameters; If the first condition is met in at least one round of iterative optimization, the current value of each of the first parameters is determined as the target control timing parameter; The atomic loading device is controlled according to the target control timing parameters.

16. The atomic loading method according to claim 15, characterized in that, The control timing parameters further include at least one second parameter, and each round of iterative optimization includes: Select a parameter to be optimized from the at least one first parameter, determine an evaluation index from the at least one second parameter, adjust the parameter to be optimized until the evaluation index meets the second condition, and determine the current value of the parameter to be optimized as the local optimum value of this round of optimization.

17. An electronic device, characterized in that, The system includes a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that the processor is configured to implement the atomic loading method as described in any one of claims 12 to 16 when executing the computer program.

18. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the atomic loading method as described in any one of claims 12 to 16.

19. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the atomic loading method as described in any one of 12 to 16.

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