Compensation system and method for second-order Doppler frequency shift and electronic equipment

Abstract

The invention relates to a second-order Doppler frequency shift compensation system, a second-order Doppler frequency shift compensation method and electronic equipment. The system comprises a current source, a controller and two current-carrying rings which are arranged in parallel and coaxially, the two current-carrying rings are arranged on the two sides of an ion trap, and each current-carrying ring is wound with an electrified coil; the current source is connected with the electrified coils wound on the current-carrying rings; the controller is in communication connection with the current sources. The controller is used for controlling the current source to introduce excitation currents with opposite flowing directions into the electrified coils of the two current-carrying rings under the condition that the ion trap is a multi-ion system, so as to generate a gradient magnetic field at the midpoint of a connecting line of circle centers of the two current-carrying rings; the second-order Zeeman frequency shift generated by the gradient magnetic field is used for compensating the second-order Doppler frequency shift. By adopting the system, the process of reducing the second-order Doppler effect becomes simple.

Description

Technical Field

[0001] The present application relates to the field of electromagnetic field technology, and in particular to a second-order Doppler frequency shift compensation system, method and electronic equipment. Background Art

[0002] When the ion Paul trap is a multi-ion system, the ions on the relatively outer side will be repelled by the Coulomb repulsion from the ions in the center and deviate from the center of the potential well, resulting in additional micro-motion. The second-order Doppler frequency shift caused by the additional micro-motion will cause a large error in the frequency of the ground state hyperfine splitting, reduce the fidelity of microwave control of the internal state of the ion, and have an inhibitory effect on further improving the performance of microwave clocks, improving the fidelity of quantum gates, and extending the coherence time of quantum bits.

[0003] In order to reduce the second-order Doppler frequency shift caused by ion deviation from the center of the trap, the current solution is to use cooperative cooling technology to trap the target ions on the central axis of the ion trap, so that the average deviation distance of the ions from the center of the trap is smaller, thereby reducing the second-order Doppler effect caused by additional micro-motion.

[0004] However, the above method has a problem in that the process of reducing the second-order Doppler effect becomes complicated. Summary of the invention

[0005] Based on this, it is necessary to provide a second-order Doppler frequency shift compensation system, method and electronic device that can simplify the process of reducing the second-order Doppler effect in order to solve the above technical problems.

[0006] In a first aspect, the present application provides a second-order Doppler frequency shift compensation system, the system comprising a current source, a controller and two current-carrying rings arranged in parallel and coaxially, the two current-carrying rings being arranged on both sides of an ion trap, each current-carrying ring being wound with a powered coil; the current source being connected to the powered coils wound on each current-carrying ring; and the controller being respectively connected to the current source for communication;

[0007] The controller is used to control the current source to pass excitation currents with opposite flow directions into the energized coils of the two current-carrying rings when the ion trap is a multi-ion system, so as to generate a gradient magnetic field at the midpoint of the line connecting the centers of the two current-carrying rings; the second-order Zeeman frequency shift generated by the gradient magnetic field is used to compensate for the second-order Doppler frequency shift.

[0008] In one embodiment, a plurality of independently controllable energized coils are wound around each current-carrying ring.

[0009] In one embodiment, the current-carrying ring includes a plurality of concentrically arranged sub-current-carrying rings, and each sub-current-carrying ring has a different radius.

[0010] In one embodiment, the radius of one of the sub-current-carrying rings is The distance between the two current-carrying rings is Where R is the length.

[0011] In a second aspect, the present application also provides a method for compensating a second-order Doppler frequency shift, the method comprising:

[0012] When the ion trap is a multi-ion system, the control current source passes excitation currents in opposite directions through the energized coils of the current-carrying rings on both sides of the ion trap to generate a gradient magnetic field at the midpoint of the line connecting the centers of the two current-carrying rings; the second-order Zeeman frequency shift generated by the gradient magnetic field is used to compensate for the second-order Doppler frequency shift.

[0013] In one embodiment, the method further comprises:

[0014] At least one of the number of turns of the energized coil of the current-carrying loop, the current value of the excitation current, and the radius of the current-carrying loop is adjusted to adjust the magnitude of the gradient magnetic field.

[0015] In one embodiment, each current-carrying ring is wound with a plurality of independently controllable energized coils, and the above-mentioned adjustment of the number of turns of the energized coils of the current-carrying ring includes:

[0016] The number of the energized coils through which the current source passes the excitation current is controlled to adjust the number of turns of the energized coils.

[0017] In one embodiment, the current-carrying ring includes a plurality of concentrically arranged sub-current-carrying rings, each of which has a different radius. The above-mentioned adjustment process of the radius of the current-carrying ring includes:

[0018] The current source is controlled to pass an excitation current into the sub-current-carrying ring of the target radius to adjust the radius of the current-carrying ring.

[0019] In one embodiment, the method further comprises:

[0020] Based on the size of the ion trap, the number of turns of the energized coil wound on the current-carrying ring corresponding to the ion trap, the size of the excitation current, and the coil radius of the current-carrying ring are determined.

[0021] In one embodiment, the method further comprises:

[0022] Based on the gradient magnetic field generated at the midpoint of the line connecting the centers of the two current-carrying rings, the gradient magnetic field generated at any point within a preset spatial range with the midpoint as a reference point is determined.

[0023] In a third aspect, the present application further provides an electronic device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the following steps are implemented:

[0024] When the ion trap is a multi-ion system, the control current source passes excitation currents in opposite directions through the energized coils of the current-carrying rings on both sides of the ion trap to generate a gradient magnetic field at the midpoint of the line connecting the centers of the two current-carrying rings; the second-order Zeeman frequency shift generated by the gradient magnetic field is used to compensate for the second-order Doppler frequency shift.

[0025] In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the following steps are implemented:

[0026] When the ion trap is a multi-ion system, the control current source passes excitation currents in opposite directions through the energized coils of the current-carrying rings on both sides of the ion trap to generate a gradient magnetic field at the midpoint of the line connecting the centers of the two current-carrying rings; the second-order Zeeman frequency shift generated by the gradient magnetic field is used to compensate for the second-order Doppler frequency shift.

[0027] In a fifth aspect, the present application further provides a computer program product, including a computer program, which implements the following steps when executed by a processor:

[0028] When the ion trap is a multi-ion system, the control current source passes excitation currents in opposite directions through the energized coils of the current-carrying rings on both sides of the ion trap to generate a gradient magnetic field at the midpoint of the line connecting the centers of the two current-carrying rings; the second-order Zeeman frequency shift generated by the gradient magnetic field is used to compensate for the second-order Doppler frequency shift.

[0029] The above-mentioned second-order Doppler frequency shift compensation system, method and electronic device, when the ion trap is a multi-ion system, controls the current source to pass excitation currents in opposite directions through the energized coils of the current-carrying rings on both sides of the ion trap, so as to generate a gradient magnetic field at the midpoint of the line connecting the centers of the two current-carrying rings; the second-order Zeeman frequency shift generated by the gradient magnetic field is used to compensate for the second-order Doppler frequency shift; in this system, compared with the method of compensating the second-order Doppler frequency shift using cooperative cooling technology, the present application generates a gradient magnetic field by passing excitation currents in opposite directions through the current-carrying rings on both sides of the ion trap, without the need to add additional cooling particles or laser sources, and without the need for a complex cooling mechanism, thereby making the process of reducing the second-order Doppler effect simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 is an internal structure diagram of a second-order Doppler frequency shift compensation system in one embodiment;

[0032] Figure 2 A schematic diagram of magnetic field distribution during COMSOL simulation using multi-physics field simulation in one embodiment;

[0033] Figure 3 is a structural block diagram of a second-order Doppler frequency shift compensation device in one embodiment;

[0034] Figure 4 is a diagram of the internal structure of an electronic device in one embodiment; Description of the drawings:

[0036] Current source 10 , controller 11 , current carrying ring 12 . DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0038] Trapping ions in a vacuum ion trap can effectively isolate the influence of external environmental disturbances such as temperature, humidity, and pressure fluctuations, and is independent of the internal electronic structure of the trapped ions. Therefore, it is very suitable for studying the interaction between light and ion ensembles. There are two main configurations of ion traps: the Penning trap that traps ions using the superposition of electrostatic and static magnetic fields, and the Paul trap that traps ions using alternating electric fields. Compared with the Penning trap, the Paul trap does not require an additional magnetic field to trap ions, has less effect on the internal state of the ions, has a variety of configurations, is easy to implement and miniaturize, and has a relatively open structure that is more conducive to the feeding and detection of lasers. It has been more widely used in the fields of ion microwave clocks, ion optical clocks, quantum computing, quantum simulation, and precision spectral measurement.

[0039] In the research fields of atomic clocks, quantum computing and simulation based on ion traps, 171Yb+ and 113Cd+ are widely used. The use of monochromatic microwaves to manipulate the transition of ions between ground state hyperfine energy levels can achieve high-performance microwave clocks, single-bit operations, and quantum bit coherence time measurements. However, for multi-ion systems, the second-order Doppler frequency shift caused by additional micro-motion will cause a large error in the frequency of ground state hyperfine splitting, reduce the fidelity of microwave-controlled ion internal states, and inhibit further improvement of microwave clock performance, improvement of quantum gate fidelity, and extension of quantum bit coherence time.

[0040] In a multi-ion system, the ions located on the relatively outer side will be repelled by the Coulomb repulsion from the ions located in the center and thus deviate from the center of the potential well, resulting in additional micro-motion. When the distance from the center of the well is r, the second-order Doppler frequency shift (δv SODS ) is:

[0041]

[0042] Where v0 is the frequency of the ground state hyperfine level transition of the ion, Q and M are the mass and charge of the ion respectively, VRF is the RF voltage applied to the radial trapping electrode, Ω is the RF driving frequency of the ion trap, r0 is the size characteristic parameter of the ion trap, indicating the shortest distance from the electrode to the center of the trap, c is the speed of light, <r 2 > represents the r of the entire ionic system 2 The average value of .

[0043] In order to reduce the second-order Doppler frequency shift caused by ion deviation from the center of the trap, the current solution is to use cooperative cooling technology to trap the target ions on the central axis of the ion trap, so that the average deviation distance of the ions from the center of the trap is smaller, thereby reducing the second-order Doppler effect caused by additional micro-motion.

[0044] Collaborative cooling is a technology that uses lasers to cool one particle (coolant particle) and then cools another particle (target particle) through interaction. For a dual-ion crystal in a collaborative cooling state, heavier ions will form a cylindrical structure that surrounds lighter ions. The lighter ions will gather at the center of the trap, with a small offset from the center of the trap, and the second-order Doppler frequency shift caused by additional micro-motion is also small. The disadvantage of this scheme is that it will increase the complexity of the system, is expensive, and the target ions that can be cooled are limited. Collaborative cooling requires laser cooling of the coolant particles first, which often requires the introduction of additional multiple laser beams, increasing the cost of the entire ion trap system and the difficulty of building the system; if you want to cool the ytterbium ions widely used in ion microwave clocks and ion trap quantum computing to the center of the potential well, you need to find a coolant ion with a mass greater than 171Yb+, which is difficult. Therefore, this cooling scheme is not suitable for reducing the second-order Doppler frequency shift of 171Yb+ multi-ion crystals.

[0045] According to some embodiments of the present application, referring to Figure 1 , a second-order Doppler frequency shift compensation system is provided. The system comprises a current source 10, a controller 11 and two current-carrying rings 12 arranged in parallel and coaxially, the two current-carrying rings 12 are arranged on both sides of the ion trap, and each current-carrying ring 12 is wound with a powered coil; the current source 10 is connected to the powered coil wound on each current-carrying ring 12; the controller 11 is respectively connected to the current source 10 in communication;

[0046] The controller 11 is used to control the current source 10 to pass excitation currents with opposite flow directions into the energized coils of the two current-carrying rings 12 when the ion trap is a multi-ion system, so as to generate a gradient magnetic field at the midpoint of the line connecting the centers of the two current-carrying rings 12; the second-order Zeeman frequency shift generated by the gradient magnetic field is used to compensate for the second-order Doppler frequency shift.

[0047] Among them, the gradient magnetic field refers to the change in the intensity of the magnetic field in space. Within a certain spatial range, the magnetic field intensity changes with position.

[0048] In the embodiment of the present application, the current source 10 provides the required current for the second-order Doppler shift compensation system. The current source 10 can adjust the intensity and flow direction of the current flowing into the energized coil so as to meet the requirements of different experimental conditions.

[0049] The controller 11 monitors and adjusts the output of the current in real time through a communication connection with the current source 10. In some embodiments, the controller 11 can also dynamically optimize the output strategy of the current source 10 according to the change of the ion state in the ion trap.

[0050] Two current-carrying rings 12 are placed in parallel and coaxially on both sides of the ion trap. A power-carrying coil is wound around each current-carrying ring 12 so as to generate an effective magnetic field after being energized. When the controller 11 adjusts the current source 10 so that excitation currents in opposite directions flow into the power-carrying coils of the two current-carrying rings 12, a gradient magnetic field will be formed at the midpoint of the line connecting the centers of the two current-carrying rings 12.

[0051] In a multi-ion system, ions are affected by the Coulomb repulsion of other ions and may shift, resulting in micromotion. The second-order Doppler frequency shift caused by the additional micromotion will cause a large error in the frequency of the ground state hyperfine splitting, reducing the fidelity of microwave control of the internal state of ions. The formation of a gradient magnetic field introduces a second-order Zeeman frequency shift. The second-order Zeeman frequency shift can be used to compensate for the second-order Doppler frequency shift caused by ion micromotion.

[0052] In some embodiments, two identical current-carrying rings 12 are placed in parallel and coaxially, and each current-carrying ring 12 is wound with N turns of energized coils. When the two current-carrying rings 12 are fed with anti-phase currents, the magnetic field in the center area of ​​the two rings is a uniform gradient magnetic field similar to that generated by an anti-Helmholtz coil, but with better gradient uniformity. The gradient magnitude of the magnetic field can be adjusted by adjusting the number of coil turns N and the current intensity I. The gradient field Maxwell coil is installed in the direction perpendicular to the ion trap (radial direction), and the magnetic field intensity (scalar) generated in the radial direction can be expressed as follows:

[0053] B(r)=k*r

[0054] Where r (mm) is the distance from the center of the trap, k (mT / mm) is the magnetic field gradient, and the second-order Zeeman relative frequency shift (δν SOZS ) is expressed as follows:

[0055]

[0056] Among them, g I and g J are the electronic Landég factor and the nuclear Landég factor of the ion, μ B is the Bohr magneton, and h is the Planck constant. The sum of the second-order Doppler shift and the second-order Zeeman shift of the ion is expressed as follows:

[0057]

[0058] Therefore, choosing a suitable magnetic field gradient can simultaneously eliminate the second-order Doppler frequency shift and the second-order Zeeman frequency shift of the ion ground state hyperfine energy level transition, and the ion is insensitive to the trapped position, and the internal hyperfine spin of the ion can be manipulated more accurately using microwaves. For the commonly used 171Yb+ and 113Cd+ plasmas, under typical ion trap configurations and trapped electrical parameters, the magnetic field gradient is about 10 -4 mT / mm, by changing the number of turns of the gradient field Maxwell coil, the excitation current and the coil radius conditions, a gradient magnetic field that meets the conditions can be generated.

[0059] In the above embodiment, when the ion trap is a multi-ion system, the control current source passes an excitation current in opposite directions through the energized coils of the current-carrying rings on both sides of the ion trap to generate a gradient magnetic field at the midpoint of the line connecting the centers of the two current-carrying rings; the second-order Zeeman frequency shift generated by the gradient magnetic field is used to compensate for the second-order Doppler frequency shift; in this system, compared with the method of compensating for the second-order Doppler frequency shift using collaborative cooling technology, the present application generates a gradient magnetic field by passing excitation currents in opposite directions through the current-carrying rings on both sides of the ion trap, without the need to add additional cooling particles or laser sources, and without the need for a complex cooling mechanism, thereby making the process of reducing the second-order Doppler effect simple.

[0060] According to some embodiments of the present application, a plurality of independently controllable energized coils are wound around each current-carrying ring 12 .

[0061] In the embodiment of the present application, each current-carrying ring 12 is wound with a plurality of independently controllable energized coils.

[0062] By adjusting the number of turns of the energized coil, the desired electromagnetic field can be generated under different experimental conditions. For example, increasing the number of turns of a particular energized coil will cause it to generate a stronger gradient magnetic field, thereby strengthening the effect on ion movement.

[0063] In some embodiments, a plurality of independently controllable energized coils are wound around each current-carrying ring 12, so that a complex electromagnetic field configuration can be realized to adapt to different experimental conditions. For example, the current of each energized coil can be adjusted according to the distribution and state of the ion population in the ion trap, so that the magnetic field on one side is enhanced and the magnetic field on the other side is weakened, thereby forming a desired gradient magnetic field.

[0064] In the above embodiment, a plurality of independently controllable energized coils are wound around each current-carrying ring 12, so that the intensity of the gradient magnetic field can be adjusted more flexibly. The controller 11 can more accurately adjust the number of energized coils through which the current source 10 passes the excitation current, so as to adjust the number of turns of the energized coils, thereby effectively changing the magnetic field intensity generated by each energized coil.

[0065] According to some embodiments of the present application, the current-carrying ring 12 includes a plurality of concentrically arranged sub-current-carrying rings 12 , and each sub-current-carrying ring 12 has a different radius.

[0066] In the embodiment of the present application, the current-carrying ring 12 is composed of a plurality of concentrically arranged sub-current-carrying rings 12 , and each sub-current-carrying ring 12 has a different radius.

[0067] The difference in radius of each sub-current-carrying ring 12 enables them to cover different spatial regions when generating a magnetic field, generating electromagnetic fields of different intensities. The gradient magnetic field generated by the sub-current-carrying ring 12 with a larger radius is relatively broad, which is suitable for regulating the movement of ions in a large range, while the sub-current-carrying ring 12 with a smaller radius can generate a more concentrated gradient magnetic field. In this way, the second-order Doppler shift compensation system can achieve efficient regulation of the gradient magnetic field to meet different experimental requirements.

[0068] By changing the radius of the daughter current ring 12, the compensation system can control the spatial distribution of the magnetic field in the ion trap, so that the larger daughter current ring 12 produces a wider magnetic field in the outer area, which is suitable for controlling ions far away from the center of the ion trap; while the smaller daughter current ring 12 can produce a more concentrated magnetic field in the central area of ​​the ion trap, so as to more accurately control the movement of ions located in the center.

[0069] In some embodiments, the radius of the current-carrying ring 12 can be adjusted by controlling the current in each sub-current-carrying ring 12. The controller 11 can adjust the current intensity output by the current source 10 to each sub-current-carrying ring 12 to change their respective magnetic field effects. When the controller 11 needs to adjust the magnetic field intensity or distribution of the compensation system, it can increase or decrease the current of some sub-current-carrying rings 12, thereby adjusting the radius and magnetic field influence range of these sub-current-carrying rings 12. For example, the current of some sub-current-carrying rings 12 can be increased to enhance the magnetic field effect they generate, thereby more strongly confining the outer ions; while other sub-current-carrying rings 12 can reduce the current, thereby weakening their magnetic field effects and concentrating the magnetic field in the central area of ​​the ion trap.

[0070] In the above embodiment, by adjusting the current of the sub-current-carrying rings with different radii, the compensation system can adjust the intensity of the gradient magnetic field and reduce the second-order Doppler frequency shift caused by ion deviation.

[0071] According to some embodiments of the present application, the radius of one of the sub-current-carrying rings 12 is The distance between the two current-carrying rings 12 is

[0072] Wherein, R is the length, and R can be a positive number.

[0073] In the embodiment of the present application, the radius of one of the sub-current-carrying rings 12 is It will be adjusted according to the requirements of the experiment. The sub-carrier ring 12 with a smaller radius is usually located in the central area of ​​the ion trap, and can generate a concentrated magnetic field to control the movement of ions in the central area; while the sub-carrier ring 12 with a larger radius is suitable for a larger range of space, and is usually located in the peripheral area of ​​the ion trap to regulate the movement of ions away from the center. By adjusting the radius of these sub-carrier rings 12, the compensation system can achieve magnetic field configurations within different ranges, so as to be optimized accordingly according to the distribution and state of the ion population.

[0074] The distance between two current-carrying rings 12 This determines the magnetic field interaction between different sub-current-carrying rings 12 and the gradient of the gradient magnetic field. The size of will affect the spatial distribution of the gradient magnetic field, and thus affect the generation of the gradient magnetic field. If the spacing is large, the gradient magnetic field generated by the two current-carrying rings 12 will have a wider range of action, which is suitable for applications that require larger spatial control; and if the spacing is small, the generated gradient magnetic field will be more concentrated, which can provide more precise control.

[0075] In the above embodiment, by adjusting the radius of the sub-current-carrying ring and the spacing between the two current-carrying rings, the controller can adjust the current intensity of each sub-current-carrying ring in the compensation system in real time, thereby dynamically changing their radius and spacing and optimizing the magnetic field configuration. This not only improves the flexibility and accuracy of the gradient magnetic field control, but also can effectively compensate for the second-order Doppler frequency shift caused by ion micromotion, thereby improving the stability and measurement accuracy of the compensation system.

[0076] According to some embodiments of the present application, a second-order Doppler shift compensation method is provided, wherein the method is applied to Figure 1 The controller in the example is used to illustrate the following steps:

[0077] When the ion trap is a multi-ion system, the control current source passes excitation currents in opposite directions through the energized coils of the current-carrying rings on both sides of the ion trap to generate a gradient magnetic field at the midpoint of the line connecting the centers of the two current-carrying rings; the second-order Zeeman frequency shift generated by the gradient magnetic field is used to compensate for the second-order Doppler frequency shift.

[0078] In the embodiment of the present application, the current source provides the required current for the second-order Doppler shift compensation system. The current source can adjust the intensity and flow direction of the current passed into the energized coil so that it can meet the requirements of different experimental conditions.

[0079] The controller monitors and adjusts the output of the current in real time through a communication connection with the current source. In some embodiments, the controller can also dynamically optimize the output strategy of the current source according to the change of the ion state in the ion trap.

[0080] Two current-carrying rings are placed in parallel and coaxially on both sides of the ion trap. A power-carrying coil is wound around each current-carrying ring to generate an effective magnetic field after power is applied. When the controller adjusts the current source so that the power-carrying coils of the two current-carrying rings flow with excitation currents in opposite directions, a gradient magnetic field will be formed at the midpoint of the line connecting the centers of the two current-carrying rings.

[0081] In a multi-ion system, ions are affected by the Coulomb repulsion of other ions and may shift, resulting in micromotion. The second-order Doppler frequency shift caused by the additional micromotion will cause a large error in the frequency of the ground state hyperfine splitting, reducing the fidelity of microwave control of the internal state of ions. The formation of a gradient magnetic field introduces a second-order Zeeman frequency shift. The second-order Zeeman frequency shift can be used to compensate for the second-order Doppler frequency shift caused by ion micromotion.

[0082] In some embodiments, two identical current-carrying rings are placed in parallel and coaxially, and each current-carrying ring is wound with N turns of energized coils. When the two current-carrying rings are fed with anti-phase currents, the magnetic field in the center area of ​​the two rings is a uniform gradient magnetic field similar to that generated by an anti-Helmholtz coil, but with better gradient uniformity. The gradient magnitude of the magnetic field can be adjusted by adjusting the number of coil turns N and the current intensity I. The gradient field Maxwell coil is installed in the direction perpendicular to the ion trap (radial direction), and the magnetic field intensity (scalar) generated in the radial direction can be expressed as follows:

[0083] B(r)=k*r

[0084] Where r (mm) is the distance from the center of the trap, k (mT / mm) is the magnetic field gradient, and the second-order Zeeman relative frequency shift (δν SOZS ) is expressed as follows:

[0085]

[0086] Among them, g I and g J are the electronic Landég factor and the nuclear Landég factor of the ion, μ B is the Bohr magneton, and h is the Planck constant. The sum of the second-order Doppler shift and the second-order Zeeman shift of the ion is expressed as follows:

[0087]

[0088]

[0089] Therefore, choosing a suitable magnetic field gradient can simultaneously eliminate the second-order Doppler frequency shift and the second-order Zeeman frequency shift of the ion ground state hyperfine energy level transition, and the ion is insensitive to the trapped position, and the internal hyperfine spin of the ion can be manipulated more accurately using microwaves. For the commonly used 171Yb+ and 113Cd+ plasmas, under typical ion trap configurations and trapped electrical parameters, the magnetic field gradient is about 10 -4 mT / mm, by changing the number of turns of the gradient field Maxwell coil, the excitation current and the coil radius conditions, a gradient magnetic field that meets the conditions can be generated.

[0090] In the above embodiment, when the ion trap is a multi-ion system, the control current source passes an excitation current in opposite directions through the energized coils of the current-carrying rings on both sides of the ion trap to generate a gradient magnetic field at the midpoint of the line connecting the centers of the two current-carrying rings; the second-order Zeeman frequency shift generated by the gradient magnetic field is used to compensate for the second-order Doppler frequency shift; in this system, compared with the method of compensating for the second-order Doppler frequency shift using collaborative cooling technology, the present application generates a gradient magnetic field by passing excitation currents in opposite directions through the current-carrying rings on both sides of the ion trap, without the need to add additional cooling particles or laser sources, and without the need for a complex cooling mechanism, thereby making the process of reducing the second-order Doppler effect simple.

[0091] According to some embodiments of the present application, the method further includes:

[0092] At least one of the number of turns of the energized coil of the current-carrying loop, the current value of the excitation current, and the radius of the current-carrying loop is adjusted to adjust the magnitude of the gradient magnetic field.

[0093] Among them, the number of turns of the energized coil is one of the factors that determine the strength of the magnetic field. The more turns of the energized coil, the stronger the gradient magnetic field generated. By increasing or decreasing the number of turns of the energized coil in the current-carrying loop, the compensation system can adjust the strength of the gradient magnetic field, thereby changing the size of the gradient magnetic field. For example, in experiments that require a stronger gradient magnetic field, the controller can increase the number of turns of the energized coil so that the current-carrying loop can generate a greater magnetic field strength to more effectively regulate the motion state of the ions. In experiments that require a smaller gradient magnetic field, the number of turns of the energized coil can be reduced, thereby reducing the strength of the gradient magnetic field.

[0094] The current value of the excitation current directly affects the strength of the magnetic field. By adjusting the current strength provided by the current source to the current-carrying loop, the controller can adjust the magnitude of the gradient magnetic field generated. Increasing the current value will produce a stronger magnetic field, thereby increasing the strength of the gradient magnetic field, and vice versa, it will reduce the gradient magnetic field.

[0095] The radius of the current-carrying ring determines the distribution range of the magnetic field. By adjusting the radius of the current-carrying ring, the spatial distribution of the magnetic field can be changed, thereby adjusting the gradient of the magnetic field. For example, a larger radius generally results in a wider range of magnetic field action, which is suitable for applications that require larger spatial control; while a smaller radius results in a more concentrated magnetic field, resulting in a stronger control effect on the central area of ​​the ion group.

[0096] In the embodiment of the present application, the gradient magnetic field can be adjusted by adjusting the number of turns of the energized coil, the current value of the excitation current, and the radius of the current-carrying ring. By jointly adjusting the number of turns of the energized coil, the current value, and the radius of the current-carrying ring, the compensation system can dynamically adjust the gradient magnetic field under different experimental requirements and optimize the ion control effect. For example, in the case of an offset or micro-motion of the ion population, the compensation system can generate a more appropriate magnetic field gradient by adjusting these parameters, thereby effectively compensating for the second-order Doppler shift and improving the accuracy and stability of the experiment.

[0097] In the above embodiment, by adjusting parameters such as the number of turns of the energized coil of the current-carrying ring, the current value of the excitation current, and the radius of the current-carrying ring, the compensation system can flexibly control the intensity and distribution of the gradient magnetic field, thereby achieving regulation of the position and motion state of the ions.

[0098] According to some embodiments of the present application, a plurality of independently controllable energized coils are wound around each current-carrying ring, and the number of turns of the energized coils of the current-carrying ring is adjusted, including:

[0099] The number of the energized coils through which the current source passes the excitation current is controlled to adjust the number of turns of the energized coils.

[0100] In the embodiment of the present application, a plurality of independently controllable energized coils are wound around each current-carrying ring.

[0101] By adjusting the number of turns of the energized coil, the desired electromagnetic field can be generated under different experimental conditions. For example, increasing the number of turns of a particular energized coil will cause it to generate a stronger gradient magnetic field, thereby strengthening the effect on ion movement.

[0102] In some embodiments, multiple independently controllable energized coils are wound around each current-carrying ring, which can realize complex electromagnetic field configuration to adapt to different experimental conditions. For example, the current of each energized coil can be adjusted according to the distribution and state of the ion population in the ion trap, so that the magnetic field on one side is enhanced and the magnetic field on the other side is weakened, thereby forming a desired gradient magnetic field.

[0103] In the above embodiment, each current-carrying ring is wound with a plurality of independently controllable energized coils, which can more flexibly adjust the intensity of the gradient magnetic field. The controller can more accurately adjust the number of energized coils through which the current source passes the excitation current, so as to adjust the number of turns of the energized coils, thereby effectively changing the magnetic field intensity generated by each energized coil.

[0104] According to some embodiments of the present application, the current-carrying ring includes a plurality of concentrically arranged sub-current-carrying rings, each of which has a different radius, and the radius of the current-carrying ring is adjusted, including:

[0105] The current source is controlled to pass an excitation current into the sub-current-carrying ring of the target radius to adjust the radius of the current-carrying ring.

[0106] In an embodiment of the present application, the current-carrying ring is composed of a plurality of concentrically arranged sub-current-carrying rings, and each sub-current-carrying ring has a different radius.

[0107] The difference in radius of each sub-carrier ring enables them to cover different spatial regions when generating magnetic fields, generating electromagnetic fields of different intensities. Sub-carrier rings with larger radii generate wider gradient magnetic fields, which are suitable for regulating ion movement over a large range, while sub-carrier rings with smaller radii can generate more concentrated gradient magnetic fields. In this way, the second-order Doppler shift compensation system can achieve efficient regulation of the gradient magnetic field to meet different experimental requirements.

[0108] By changing the radius of the daughter current ring, the compensation system can control the spatial distribution of the magnetic field in the ion trap, so that the larger daughter current ring produces a wider magnetic field in the outer area, which is suitable for controlling ions far away from the center of the ion trap; while the smaller daughter current ring can produce a more concentrated magnetic field in the central area of ​​the ion trap to more accurately control the movement of ions located in the center.

[0109] In some embodiments, the radius of the current-carrying ring can be adjusted by controlling the current in each sub-current-carrying ring. The controller can adjust the current intensity output by the current source to each sub-current-carrying ring to change their respective magnetic field effects. When the controller needs to adjust the magnetic field intensity or distribution of the compensation system, it can increase or decrease the current of certain sub-current-carrying rings to adjust the radius and magnetic field influence range of these sub-current-carrying rings. For example, the current of certain sub-current-carrying rings can be increased to enhance the magnetic field effect they produce, thereby providing stronger confinement to the outer ions; while other sub-current-carrying rings can reduce the current, thereby weakening their magnetic field effect and concentrating the magnetic field in the central area of ​​the ion trap.

[0110] In the above embodiment, by adjusting the current of the sub-current-carrying rings with different radii, the compensation system can adjust the intensity of the gradient magnetic field and reduce the second-order Doppler frequency shift caused by ion deviation.

[0111] According to some embodiments of the present application, the method further includes:

[0112] Based on the size of the ion trap, the number of turns of the energized coil wound on the current-carrying ring corresponding to the ion trap, the size of the excitation current, and the coil radius of the current-carrying ring are determined.

[0113] Among them, the size of the ion trap is the key factor in determining the distribution of the gradient magnetic field strength. Larger ion traps require stronger gradient magnetic fields to cover the entire area, while smaller ion traps only need to control the gradient magnetic field within a smaller range. In order to adapt to ion traps of different sizes, the number of turns of the energized coil needs to be adjusted accordingly. Larger ion traps usually require more turns of energized coils to enhance the strength of the magnetic field so that the gradient magnetic field can effectively cover a wider space. On the contrary, smaller ion traps can use fewer turns of energized coils to meet the gradient magnetic field requirements. By adjusting the number of turns of the energized coil, the intensity of the generated gradient magnetic field can be controlled, thereby achieving effective control of the ion trap.

[0114] The excitation current directly affects the intensity of the gradient magnetic field. The larger the excitation current, the stronger the gradient magnetic field generated. For larger ion traps, a larger excitation current is usually required so that the excitation magnetic field can be evenly distributed throughout the ion trap. Conversely, smaller ion traps can adjust the intensity of the excitation magnetic field by reducing the excitation current, thereby avoiding an overly strong excitation magnetic field that affects the stability of the ion beam or introduces unnecessary disturbances. Therefore, choosing the appropriate excitation current size can not only meet the size requirements of the ion trap, but also adjust the accuracy of the excitation magnetic field according to experimental needs.

[0115] The radius of the current ring determines the spatial distribution range of the gradient magnetic field. For larger ion traps, a current ring with a larger radius is usually required so that the gradient magnetic field can cover a wider spatial range. On the contrary, smaller ion traps are suitable for using current rings with a smaller radius, which can concentrate the force of the gradient magnetic field, thereby achieving precise control of the center position of the ions. The radius of the current ring is closely related to the size of the ion trap. By adjusting the radius of the current ring, the gradient of the gradient magnetic field can be effectively controlled, thereby achieving regulation of the ions.

[0116] In the embodiment of the present application, it is necessary to comprehensively consider the number of turns of the energized coil, the magnitude of the excitation current, and the radius of the current-carrying ring, and to achieve the purpose of optimizing the magnetic field gradient and ion trapping by adjusting one or more of the parameters. For example, for a larger ion trap, it is possible to increase the number of turns of the energized coil and increase the intensity of the excitation current so that the gradient magnetic field can evenly cover the entire area within the ion trap. For a smaller ion trap, the number of coil turns can be reduced and the current can be reduced to obtain a suitable magnetic field strength and reduce excessive disturbances to the ion state. At the same time, by adjusting the radius of the current-carrying ring as needed, the distribution of the gradient magnetic field can be further optimized so that the gradient magnetic field is concentrated in the core area of ​​the ion population, thereby improving the trapping accuracy of the ions.

[0117] In the above embodiment, by adjusting the number of turns of the energized coil, the magnitude of the excitation current, and the radius of the current-carrying ring, the intensity and distribution of the gradient magnetic field can be controlled to optimize the ion beam control in the ion trap. In ion traps of different sizes, by reasonably selecting and adjusting these parameters, the accuracy requirements of ion trap control can be effectively achieved, and the influence of the second-order Doppler shift can be reduced, thereby improving the application effect in the fields of quantum computing, quantum simulation, and precision measurement.

[0118] According to some embodiments of the present application, the method further includes:

[0119] Based on the gradient magnetic field generated at the midpoint of the line connecting the centers of the two current-carrying rings, the gradient magnetic field generated at any point within a preset spatial range with the midpoint as a reference point is determined.

[0120] The midpoint refers to the middle position of the line connecting the centers of the two current-carrying rings.

[0121] In the embodiment of the present application, the gradient magnetic field at any other position within the preset spatial range can be further inferred through the distribution of the known midpoint gradient magnetic field.

[0122] In some embodiments, the symmetry principle can be used to obtain the gradient magnetic field generated at any point within a preset spatial range. Assuming that the gradient magnetic field at the midpoint is known, the gradient magnetic field is usually symmetric in space. If the magnetic field distribution at the midpoint is known, the magnetic field strength at other points can be inferred by the change in distance.

[0123] In some embodiments, reference Figure 2 , Figure 2 This is a schematic diagram of the magnetic field distribution when using multi-physics field simulation COMSOL; the x-axis is the position of any point between the two current-carrying rings, and 0 represents the center point; the y-axis represents the magnetic flux density; Figure 2 The figure is a schematic diagram of the x-axis magnetic field distribution corresponding to the party length R = 1m, the number of turns of the energized coil N = 100, and the excitation current I = 1A; since the magnetic field distribution at any point in the middle area of ​​the current-carrying loop cannot be expressed by analytical methods, COMSOL simulation or matrix laboratory (MATrix LABoratory, MATLAB), mathematical software Mathematica programming and other methods can be used to analyze the magnetic field generated by the coil with specific parameters, improve data analysis and visualization processing, and ensure that the generated gradient magnetic field meets the experimental requirements.

[0124] In the above embodiment, by knowing the gradient magnetic field distribution at the midpoint, the spatial distribution law of the magnetic field can be used to obtain the gradient magnetic field at other positions within the preset spatial range, which can improve efficiency.

[0125] It should be understood that, although the steps in the flowcharts involved in the above embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps is not strictly limited in order, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above embodiments may include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0126] Based on the same inventive concept, the embodiment of the present application also provides a second-order Doppler frequency shift compensation device for implementing the second-order Doppler frequency shift compensation method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more second-order Doppler frequency shift compensation device embodiments provided below can refer to the limitations of the second-order Doppler frequency shift compensation method above, and will not be repeated here.

[0127] In an exemplary embodiment, Figure 3 As shown, a second-order Doppler frequency shift compensation device is provided, comprising:

[0128] The compensation module 201 is used to control the current source to pass excitation currents with opposite directions into the energized coils of the current-carrying rings on both sides of the ion trap when the ion trap is a multi-ion system, so as to generate a gradient magnetic field at the midpoint of the line connecting the centers of the two current-carrying rings; the second-order Zeeman frequency shift generated by the gradient magnetic field is used to compensate for the second-order Doppler frequency shift.

[0129] According to some embodiments of the present application, the device further includes:

[0130] The adjustment module 202 is used to adjust at least one of the number of turns of the energized coil of the current-carrying loop, the current value of the excitation current, and the radius of the current-carrying loop to adjust the magnitude of the gradient magnetic field.

[0131] According to some embodiments of the present application, the adjustment module 202 is specifically used to control the number of energized coils through which the current source passes the excitation current, so as to adjust the number of turns of the energized coils.

[0132] According to some embodiments of the present application, the adjustment module 202 is specifically used to control the current source to pass the excitation current into the sub-current-carrying ring of the target radius to adjust the radius of the current-carrying ring.

[0133] According to some embodiments of the present application, the device further includes:

[0134] The first determination module 203 is used to determine the number of turns of the energized coil wound on the current-carrying ring corresponding to the ion trap, the size of the excitation current, and the coil radius of the current-carrying ring based on the size of the ion trap.

[0135] According to some embodiments of the present application, the device further includes:

[0136] The second determination module 204 is used to determine the gradient magnetic field generated at any point in a preset spatial range with the midpoint as a reference point based on the gradient magnetic field generated at the midpoint of the line connecting the centers of the two current-carrying rings.

[0137] Each module in the second-order Doppler shift compensation device can be implemented in whole or in part by software, hardware, or a combination thereof. Each module can be embedded in or independent of a processor in an electronic device in the form of hardware, or can be stored in a memory in the electronic device in the form of software, so that the processor can call and execute operations corresponding to each module.

[0138] In an exemplary embodiment, an electronic device is provided. The electronic device may be a controller, and its internal structure diagram may be as shown in FIG. Figure 4 As shown. The electronic device includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. The processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. The processor of the electronic device is used to provide computing and control capabilities. The memory of the electronic device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the electronic device is used to store data in the compensation process of the second-order Doppler frequency shift. The input / output interface of the electronic device is used to exchange information between the processor and an external device. The communication interface of the electronic device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a compensation method for the second-order Doppler frequency shift is implemented.

[0139] Those skilled in the art will understand that Figure 4 The structure shown in the figure is merely a block diagram of a partial structure related to the scheme of the present application, and does not constitute a limitation on the electronic device to which the scheme of the present application is applied. The specific electronic device may include more or fewer components than shown in the figure, or combine certain components, or have a different arrangement of components.

[0140] In an exemplary embodiment, an electronic device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the computer program, the following steps are implemented:

[0141] When the ion trap is a multi-ion system, the control current source passes excitation currents in opposite directions through the energized coils of the current-carrying rings on both sides of the ion trap to generate a gradient magnetic field at the midpoint of the line connecting the centers of the two current-carrying rings; the second-order Zeeman frequency shift generated by the gradient magnetic field is used to compensate for the second-order Doppler frequency shift.

[0142] In one embodiment, when the processor executes the computer program, the processor further implements the following steps:

[0143] At least one of the number of turns of the energized coil of the current-carrying loop, the current value of the excitation current, and the radius of the current-carrying loop is adjusted to adjust the magnitude of the gradient magnetic field.

[0144] In one embodiment, each current-carrying ring is wound with a plurality of independently controllable energized coils, and the processor further implements the following steps when executing the computer program:

[0145] The number of the energized coils through which the current source passes the excitation current is controlled to adjust the number of turns of the energized coils.

[0146] In one embodiment, the current-carrying ring includes a plurality of concentrically arranged sub-current-carrying rings, each of which has a different radius. When the processor executes the computer program, the following steps are also implemented:

[0147] The current source is controlled to pass an excitation current into the sub-current-carrying ring of the target radius to adjust the radius of the current-carrying ring.

[0148] In one embodiment, when the processor executes the computer program, the processor further implements the following steps:

[0149] Based on the size of the ion trap, the number of turns of the energized coil wound on the current-carrying ring corresponding to the ion trap, the size of the excitation current, and the coil radius of the current-carrying ring are determined.

[0150] In one embodiment, when the processor executes the computer program, the processor further implements the following steps:

[0151] Based on the gradient magnetic field generated at the midpoint of the line connecting the centers of the two current-carrying rings, the gradient magnetic field generated at any point within a preset spatial range with the midpoint as a reference point is determined.

[0152] In one embodiment, a computer readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the following steps are implemented:

[0153] When the ion trap is a multi-ion system, the control current source passes excitation currents in opposite directions through the energized coils of the current-carrying rings on both sides of the ion trap to generate a gradient magnetic field at the midpoint of the line connecting the centers of the two current-carrying rings; the second-order Zeeman frequency shift generated by the gradient magnetic field is used to compensate for the second-order Doppler frequency shift.

[0154] In one embodiment, when the computer program is executed by a processor, the following steps are also implemented:

[0155] At least one of the number of turns of the energized coil of the current-carrying loop, the current value of the excitation current, and the radius of the current-carrying loop is adjusted to adjust the magnitude of the gradient magnetic field.

[0156] In one embodiment, each current-carrying ring is wound with a plurality of independently controllable energized coils, and when the computer program is executed by the processor, the following steps are also implemented:

[0157] The number of the energized coils through which the current source passes the excitation current is controlled to adjust the number of turns of the energized coils.

[0158] In one embodiment, the current-carrying ring includes a plurality of concentrically arranged sub-current-carrying rings, each of which has a different radius. When the computer program is executed by the processor, the following steps are also implemented:

[0159] The current source is controlled to pass an excitation current into the sub-current-carrying ring of the target radius to adjust the radius of the current-carrying ring.

[0160] In one embodiment, when the computer program is executed by a processor, the following steps are also implemented:

[0161] Based on the size of the ion trap, the number of turns of the energized coil wound on the current-carrying ring corresponding to the ion trap, the size of the excitation current, and the coil radius of the current-carrying ring are determined.

[0162] In one embodiment, when the computer program is executed by a processor, the following steps are also implemented:

[0163] Based on the gradient magnetic field generated at the midpoint of the line connecting the centers of the two current-carrying rings, the gradient magnetic field generated at any point within a preset spatial range with the midpoint as a reference point is determined.

[0164] In one embodiment, a computer program product is provided, comprising a computer program, which, when executed by a processor, implements the following steps:

[0165] When the ion trap is a multi-ion system, the control current source passes excitation currents in opposite directions through the energized coils of the current-carrying rings on both sides of the ion trap to generate a gradient magnetic field at the midpoint of the line connecting the centers of the two current-carrying rings; the second-order Zeeman frequency shift generated by the gradient magnetic field is used to compensate for the second-order Doppler frequency shift.

[0166] In one embodiment, when the computer program is executed by a processor, the following steps are also implemented:

[0167] At least one of the number of turns of the energized coil of the current-carrying loop, the current value of the excitation current, and the radius of the current-carrying loop is adjusted to adjust the magnitude of the gradient magnetic field.

[0168] In one embodiment, each current-carrying ring is wound with a plurality of independently controllable energized coils, and when the computer program is executed by the processor, the following steps are also implemented:

[0169] The number of the energized coils through which the current source passes the excitation current is controlled to adjust the number of turns of the energized coils.

[0170] In one embodiment, the current-carrying ring includes a plurality of concentrically arranged sub-current-carrying rings, each of which has a different radius. When the computer program is executed by the processor, the following steps are also implemented:

[0171] The current source is controlled to pass an excitation current into the sub-current-carrying ring of the target radius to adjust the radius of the current-carrying ring.

[0172] In one embodiment, when the computer program is executed by a processor, the following steps are also implemented:

[0173] Based on the size of the ion trap, the number of turns of the energized coil wound on the current-carrying ring corresponding to the ion trap, the size of the excitation current, and the coil radius of the current-carrying ring are determined.

[0174] In one embodiment, when the computer program is executed by a processor, the following steps are also implemented:

[0175] Based on the gradient magnetic field generated at the midpoint of the line connecting the centers of the two current-carrying rings, the gradient magnetic field generated at any point within a preset spatial range with the midpoint as a reference point is determined.

[0176] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, an artificial intelligence (AI) processor, etc., but are not limited to this.

[0177] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, 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 application.

[0178] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A second-order Doppler frequency shift compensation system, characterized in that: The system comprises a current source, a controller and two current-carrying rings arranged in parallel and coaxially, wherein the two current-carrying rings are arranged on both sides of the ion trap, and each current-carrying ring is wound with a power-carrying coil; the current source is connected to the power-carrying coils wound on each current-carrying ring; and the controller is respectively connected to the current source for communication; The controller is used to control the current source to pass excitation currents with opposite flow directions into the energized coils of the two current-carrying rings when the ion trap is a multi-ion system, so as to generate a gradient magnetic field at the midpoint of the line connecting the centers of the two current-carrying rings; the second-order Zeeman frequency shift generated by the gradient magnetic field is used to compensate for the second-order Doppler frequency shift.

2. The system according to claim 1, characterized in that A plurality of independently controllable energized coils are wound around each of the current-carrying rings.

3. The system according to claim 1, characterized in that The current-carrying ring includes a plurality of concentrically arranged sub-current-carrying rings, and each of the sub-current-carrying rings has a different radius.

4. The system according to claim 3, characterized in that The radius of one of the sub-current-carrying rings is The distance between the two current-carrying rings is Where R is the length.

5. A method for compensating second-order Doppler frequency shift, characterized in that: The method comprises: When the ion trap is a multi-ion system, a control current source is used to pass an excitation current with opposite flow directions into the energized coils of the current-carrying rings on both sides of the ion trap, so as to generate a gradient magnetic field at the midpoint of the line connecting the centers of the two current-carrying rings; the second-order Zeeman frequency shift generated by the gradient magnetic field is used to compensate for the second-order Doppler frequency shift.

6. The method according to claim 5, characterized in that The method further comprises: At least one of the number of turns of the energized coil of the current-carrying ring, the current value of the excitation current, and the radius of the current-carrying ring is adjusted to adjust the magnitude of the gradient magnetic field.

7. The method according to claim 6, characterized in that A plurality of independently controllable energized coils are wound around each of the current-carrying rings, and the number of turns of the energized coils of the current-carrying rings is adjusted, including: The number of the energized coils through which the current source passes the excitation current is controlled to adjust the number of turns of the energized coils.

8. The method according to claim 6, characterized in that The current-carrying ring includes a plurality of concentrically arranged sub-current-carrying rings, each of which has a different radius. The adjusting process of the radius of the current-carrying ring includes: The current source is controlled to supply an excitation current to the sub-current-carrying ring of a target radius, so as to adjust the radius of the current-carrying ring.

9. The method according to claim 5, characterized in that The method further comprises: Based on the size of the ion trap, the number of turns of the energized coil wound on the current-carrying ring corresponding to the ion trap, the size of the excitation current, and the size of the coil radius of the current-carrying ring are determined.

10. The method according to claim 5, characterized in that The method further comprises: Based on the gradient magnetic field generated at the midpoint of the line connecting the centers of the two current-carrying rings, the gradient magnetic field generated at any point within a preset spatial range with the midpoint as a reference point is determined.

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