System, method and electronic device for compensating second order doppler shift

Abstract

The application relates to a system, method and electronic device for compensating second-order Doppler frequency shift. The system comprises a current source, a controller and two parallel and coaxial current-carrying rings, the two current-carrying rings are arranged on both sides of an ion trap, and a current-carrying coil is wound on each current-carrying ring; the current source is connected with the current-carrying coil wound on each current-carrying ring; the controller is in communication connection with the current source; the controller is used for controlling the current source to input excitation currents with opposite flowing directions into the current-carrying coils of the two current-carrying rings in the case that 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; and the second-order Zeeman frequency shift generated by the gradient magnetic field is used for compensating the second-order Doppler frequency shift. By using the system, the process of reducing the second-order Doppler effect can be simplified.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electromagnetic field, in particular to a second-order Doppler shift compensation system, method and electronic device. BACKGROUND

[0002] When the ion Paul trap is a multi-ion system, the ions located at the relatively outer side will deviate from the center of the potential well due to the Coulomb repulsion from the ions located at the center, thereby generating additional micro-motions. The second-order Doppler shift caused by the additional micro-motions will cause a large error in the frequency of the ground-state hyperfine splitting, thereby reducing the fidelity of the microwave control of the internal state of the ion, and inhibiting the further improvement of the performance of the microwave clock, the increase of the quantum gate fidelity, and the prolongation of the coherence time of the quantum bit.

[0003] In order to reduce the second-order Doppler shift caused by the deviation of the ion from the center of the well, the currently used solution is to use the cooperative cooling technology to confine the target ion on the central axis of the ion trap, so that the distance of the ion from the center of the well is small, thereby reducing the second-order Doppler effect caused by the additional micro-motions.

[0004] However, the above method has the problem of complicating the process of reducing the second-order Doppler effect. SUMMARY

[0005] Therefore, it is necessary to provide a second-order Doppler shift compensation system, method and electronic device which can simplify the process of reducing the second-order Doppler effect.

[0006] In a first aspect, the present application provides a second-order Doppler shift compensation system, which comprises a current source, a controller and two parallel and coaxial current-carrying rings, the two current-carrying rings are arranged on both sides of the ion trap, and each current-carrying ring is wound with a current-carrying coil; the current source is connected to the current-carrying coil wound on each current-carrying ring; the controller is in communication connection with the current source.

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

[0008] In one of the embodiments, each current-carrying ring is wound with a plurality of independently controllable current-carrying coils.

[0009] In one of the embodiments, the current-carrying ring comprises a plurality of concentrically arranged sub-current-carrying rings, and the radii of the sub-current-carrying rings are different.

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

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

[0012] In the case of a multi-ion system in the ion trap, 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, 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.

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

[0014] The magnitude of the gradient magnetic field is adjusted by adjusting at least one of the following: the number of turns of the energized coil of the current-carrying ring, the value of the excitation current, and the radius of the current-carrying ring.

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

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

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

[0018] The current source is controlled to supply excitation current to the sub-current-carrying ring of the target radius in order to adjust the radius of the current-carrying ring.

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

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

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

[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 the reference point is determined.

[0023] Thirdly, this application also provides an electronic device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to perform the following steps:

[0024] In the case of the ion trap being a multi-ion system, the control current source is used to pass excitation currents in opposite directions in 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; and 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 also provides a computer readable storage medium, which has a computer program stored thereon, and the computer program, when executed by a processor, implements the following steps:

[0026] In the case of the ion trap being a multi-ion system, the control current source is used to pass excitation currents in opposite directions in 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; and 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 also provides a computer program product, which comprises a computer program, and the computer program, when executed by a processor, implements the following steps:

[0028] In the case of the ion trap being a multi-ion system, the control current source is used to pass excitation currents in opposite directions in 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; and 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 compensation system, method and electronic device for the second-order Doppler frequency shift, in the case of the ion trap being a multi-ion system, the control current source is used to pass excitation currents in opposite directions in 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; and the second-order Zeeman frequency shift generated by the gradient magnetic field is used to compensate for the second-order Doppler frequency shift; in the system, compared with the method of compensating for the second-order Doppler frequency shift by using the cooperative cooling technology, the present application generates a gradient magnetic field by passing excitation currents in opposite directions in the current-carrying rings on both sides of the ion trap, without the need to increase additional cooling particles or laser sources, and without the need for a complex cooling mechanism, so as to make the process of reducing the second-order Doppler effect simple. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related art, the following will briefly introduce the drawings needed to be used in the description of the embodiments of the present application or the related art. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other related drawings can also be obtained without creative labor.

[0031] Figure 1 It is an internal structure diagram of the compensation system for the second-order Doppler frequency shift in an embodiment.

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

[0033] Figure 3 A structural block diagram of a compensation device for second-order Doppler shift in an embodiment;

[0034] Figure 4 An internal structure diagram of an electronic device in an embodiment; BRIEF DESCRIPTION OF DRAWINGS

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

[0037] In order to make the purposes, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application.

[0038] Trapping ions in a vacuum ion trap can better isolate the influence of external environmental temperature, humidity, pressure fluctuation and other disturbances, and does not depend on the internal electronic structure of the trapped ions, so it is very suitable for studying the interaction of light and ion system. There are two main configurations of ion traps: Penning trap using the superposition of electrostatic field and static magnetic field to trap ions and Paul trap using alternating electric field to trap ions. Compared with Penning trap, Paul trap has less influence on the internal state of ions because it does not need additional magnetic field to trap ions, and has more diverse configurations, easy to realize and miniaturize, and the relatively open structure is more conducive to the feeding and detection of laser, and has been more widely used in the fields of ion microwave clock, ion optical clock, quantum computing, quantum simulation, precise spectral measurement, etc.

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

[0040] In a multi-ion system, the ions located at the relatively outer side will be deviated from the center of the potential well due to the Coulomb repulsion from the ions located at the center, resulting in additional micro-motions. When the distance of the deviation from the center of the well is r, the formula of the second-order Doppler frequency shift (δv SODS ) contributed by the additional micro-motions is:

[0041]

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

[0043] In order to reduce the second-order Doppler frequency shift caused by the deviation of the ion from the center of the well, the currently adopted solution is to use the sympathetic cooling technology to trap the target ion at the central axis of the ion trap, so that the average distance of the ion from the center of the well is small, thereby reducing the second-order Doppler effect caused by the additional micro-motions.

[0044] Sympathetic cooling is a technology of using laser cooling of one kind of particles (coolant particles) to cool another kind of particles (target particles) through interaction. For a double-ion crystal in a sympathetic cooling state, the heavier ions will form a cylindrical structure to surround the lighter ions, and the lighter ions will gather at the center of the well, with a small distance from the center of the well and a small second-order Doppler frequency shift caused by the additional micro-motions. The disadvantage of this scheme is that it will increase the complexity of the system, the cost is high, and the target ions that can be cooled are limited. Sympathetic cooling requires laser cooling of coolant particles, which often needs to introduce additional multiple lasers, increasing the cost of the entire ion trap system and the difficulty of building the system; if it is desired to cool the ytterbium ion, which is widely used in ion microwave clocks and ion trap quantum computing, to the center of the well, it is necessary to find a coolant ion with a mass greater than 171Yb+, which presents certain difficulties. Therefore, this cooling scheme is not suitable for reducing the second-order Doppler frequency shift of the 171Yb+ multi-ion crystal.

[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 parallel and coaxial current-carrying rings 12, 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 power coil; the current source 10 is connected to the power coil wound on each current-carrying ring 12; the controller 11 is in communication connection with the current source 10 respectively;

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

[0047] The gradient magnetic field refers to the change of the strength of the magnetic field in space, that is, the change of the strength of the magnetic field with position in a certain spatial range.

[0048] In the embodiments of the present application, the current source 10 provides the required current for the compensation system of the second-order Doppler frequency shift. The current source 10 can adjust the strength and flow direction of the current passing through the current-carrying coils, so as to meet the needs of different experimental conditions.

[0049] The controller 11 monitors and adjusts the output of the current in real time through the 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 changes of the ion state in the ion trap.

[0050] The two current-carrying rings 12 are placed in parallel and coaxially on the two sides of the ion trap. Each current-carrying ring 12 is wound with a current-carrying coil to generate an effective magnetic field after being powered on. When the controller 11 adjusts the current source 10 to pass excitation currents in opposite directions through the current-carrying coils of the two current-carrying rings 12, a gradient magnetic field is formed at the midpoint of the line connecting the centers of the two current-carrying rings 12.

[0051] In a multi-ion system, the ions are affected by the Coulomb repulsion of other ions and may be shifted, resulting in the occurrence of micro-motions. The second-order Doppler frequency shift caused by the additional micro-motions will cause a large error in the frequency of the ground-state hyperfine splitting, reducing the fidelity of the microwave control of the internal state of the ion. The formation of the 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 micro-motions.

[0052] In some embodiments, two identical current-carrying rings 12 are placed in parallel and coaxially, each current-carrying ring 12 is wound with N turns of current-carrying coils, and when the two current-carrying rings 12 pass through opposite currents, the magnetic field in the central region of the two rings is a uniform gradient magnetic field similar to that generated by an anti-Helmholtz coil, but the gradient uniformity is better. By adjusting the number of turns N and the strength of the current I, the gradient size of the magnetic field can be adjusted. The gradient field Maxwell coil is installed in the direction perpendicular to the ion trap (radial direction), and the magnetic field strength (scalar) generated in the radial direction can be represented 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, the second order Zeeman relative frequency shift of the ion caused by the magnetic field (δν SOZS ) is expressed as follows:

[0055]

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

[0057]

[0058] Therefore, by selecting a proper magnetic field gradient, the second order Doppler frequency shift and the second order Zeeman frequency shift of the ion ground state hyperfine level transition can be eliminated simultaneously, the ion is not sensitive to the trapping position, and the internal hyperfine spin of the ion can be more accurately manipulated by using microwaves. For commonly used ions such as 171Yb+and 113Cd+, under typical ion trap configurations and trapping electric parameters, the magnetic field gradient is about 10 -4 mT / mm. The gradient magnetic field satisfying the condition can be generated by changing the number of turns, the excitation current, and the radius of the above-mentioned gradient field Maxwell coil.

[0059] In the above embodiment, in the case of a multi-ion system, the control current source passes excitation currents in opposite directions in 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 by using the sympathetic cooling technology, the present application generates a gradient magnetic field by passing excitation currents in opposite directions in the current-carrying rings on both sides of the ion trap, without the need to increase 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 current-carrying coils are wound on each current-carrying ring 12.

[0061] In the embodiments of the present application, a plurality of independently controllable current-carrying coils are wound on each current-carrying ring 12.

[0062] By adjusting the number of turns of the current-carrying coils, the required electromagnetic field can be generated under different experimental conditions. For example, increasing the number of turns of a specific current-carrying coil will result in a stronger gradient magnetic field generated by the coil, thereby strengthening the influence on the ion motion.

[0063] In some embodiments, multiple independently controllable current-carrying coils are wound on each current-carrying ring 12, which can realize complex electromagnetic field configurations to adapt to different experimental conditions. For example, the current of each current-carrying 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 embodiments, multiple independently controllable current-carrying coils are wound on each current-carrying ring 12, which can more flexibly adjust the strength of the gradient magnetic field. The controller 11 can more accurately adjust the number of current-carrying coils through which the current source 10 passes the excitation current, to adjust the number of turns of the current-carrying coils, thereby effectively changing the magnetic field strength generated by each current-carrying coil.

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

[0066] In the embodiments of the present application, the current-carrying ring 12 is composed of multiple concentrically arranged sub-current-carrying rings 12, each sub-current-carrying ring 12 having a different radius.

[0067] The difference in the radius of each sub-current-carrying ring 12 allows them to cover different spatial regions when generating a magnetic field, producing electromagnetic fields of different strengths. The sub-current-carrying ring 12 with a larger radius produces a more extensive gradient magnetic field, which is suitable for adjusting the motion of ions in a large range, while the sub-current-carrying ring 12 with a smaller radius can produce a more concentrated gradient magnetic field. In this way, the compensation system of the second-order Doppler shift can effectively adjust the gradient magnetic field to meet different experimental requirements.

[0068] By changing the radius of the sub-current-carrying ring 12, the compensation system can control the spatial distribution of the magnetic field in the ion trap, so that the larger sub-current-carrying ring 12 produces a more extensive magnetic field in the outer region, which is suitable for regulating ions far from the center of the ion trap; while the smaller sub-current-carrying ring 12 can produce a more concentrated magnetic field in the central region of the ion trap, to more accurately control the motion of ions located in the center.

[0069] In some embodiments, the radius of the current-carrying rings 12 can be adjusted by controlling the current in each of the sub-rings 12. The controller 11 can adjust the current output from the current source 10 to each of the sub-rings 12 to change their respective magnetic field effects. When the controller 11 needs to adjust the magnetic field strength or distribution of the compensation system, it can increase or decrease the current in certain sub-rings 12 to adjust the radius and magnetic field effect range of these sub-rings 12. For example, the current in certain sub-rings 12 can be increased to enhance their magnetic field effects to provide stronger confinement of the outer ions; while the current in other sub-rings 12 can be decreased to weaken their magnetic field effects to concentrate the magnetic field in the central region of the ion trap.

[0070] In the above embodiments, by adjusting the current of the sub-rings 12 with different radii, the compensation system can adjust the strength of the gradient magnetic field to reduce the second-order Doppler frequency shift caused by ion drift.

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

[0072] where R is the length, which can be a positive number.

[0073] In the embodiments of the present application, the radius of one of the sub-rings 12 is which can be adjusted according to the requirements of the experiment. The sub-rings 12 with smaller radii are usually located in the central region of the ion trap and can generate a concentrated magnetic field to control the motion of the ions in the central region; while the sub-rings 12 with larger radii are suitable for a larger range of space and are usually located in the peripheral region of the ion trap to adjust the motion of the ions away from the center. By adjusting the radii of these sub-rings 12, the compensation system can achieve different magnetic field configurations in different ranges to optimize the distribution and state of the ion population accordingly.

[0074] The spacing between two current-carrying rings 12 is which determines the magnetic field interaction between different sub-rings 12 and the gradient of the gradient magnetic field. The size of the spacing affects the spatial distribution of the gradient magnetic field, which in turn affects the generation of the gradient magnetic field. If the spacing is large, the gradient magnetic field generated by the two current-carrying rings 12 has a wide range of action, which is suitable for applications that require large space regulation; while if the spacing is small, the generated gradient magnetic field is more concentrated, which can provide more precise control.

[0075] In the above embodiments, 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 the radius and spacing of the sub-current-carrying rings, optimizing the magnetic field configuration. This not only improves the flexibility and accuracy of the gradient magnetic field control, but also effectively compensates for the second-order Doppler frequency shift caused by ion micro-motion, thereby improving the stability and measurement accuracy of the compensation system.

[0076] According to some embodiments of the present application, a method for compensating for a second-order Doppler frequency shift is provided. The method is applied to a controller in Figure 1 The controller is described as an example, including the following steps:

[0077] In the case of a multi-ion system, the current source is used to generate excitation currents in opposite directions in the current-carrying coils on both sides of the ion trap, thereby generating 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 embodiments of the present application, the current source provides the required current for the compensation system of the second-order Doppler frequency shift. The current source can adjust the intensity and direction of the current flowing into the current-carrying coil, so that it can meet the needs of different experimental conditions.

[0079] The controller communicates with the current source to monitor and adjust the output of the current in real time. In some embodiments, the controller can also dynamically optimize the output strategy of the current source according to the changes in the ion state in the ion trap.

[0080] The two current-carrying rings are placed in parallel and coaxially on both sides of the ion trap. Each current-carrying ring is wound with a current-carrying coil to generate an effective magnetic field after being powered on. When the controller adjusts the current source to make the current-carrying coils of the two current-carrying rings flow 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 be offset, resulting in the occurrence of micro-motion. The second-order Doppler frequency shift caused by additional micro-motion will cause a large error in the frequency of the ground-state hyperfine splitting, reducing the fidelity of microwave control of the ion internal state. The formation of the 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 micro-motion.

[0082] In some embodiments, two identical current-carrying loops are placed in parallel and coaxially, each of which is wound with N turns of energized coil, and when the two current-carrying loops are connected with opposite currents, the magnetic field in the central region of the two loops is similar to the uniform gradient magnetic field generated by the anti-Helmholtz coil, but the gradient uniformity is better. By adjusting the number of turns N and the current intensity I of the coil, the gradient size of the magnetic field can be adjusted. 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 represented 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 ) of the ion caused by the magnetic field is represented as follows:

[0085]

[0086] where g I and g J are the electron Landé g factor and the nuclear Landé g factor of the ion, respectively, μ B is the Bohr magneton, and h is the Planck constant. The sum of the second-order Doppler frequency shift and the second-order Zeeman frequency shift of the ion is represented as follows:

[0087]

[0088]

[0089] Therefore, by selecting a suitable magnetic field gradient, the second-order Doppler frequency shift and the second-order Zeeman frequency shift of the ion ground state hyperfine energy level transition can be eliminated at the same time, the ion is not sensitive to the trapping position, and the internal hyperfine spin of the ion can be more accurately manipulated using microwaves. For commonly used 171Yb+ and 113Cd+ ions, under the typical ion trap configuration and trapping electric parameters, the magnetic field gradient is about 10 -4 mT / mm, and the gradient magnetic field that meets the conditions can be generated by changing the number of turns, the excitation current and the coil radius of the above gradient field Maxwell coil.

[0090] In the above embodiments, in the case of a multi-ion system, the control current source is used to pass excitation currents in opposite directions in 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 by using the cooperative cooling technology, the present application generates a gradient magnetic field by passing excitation currents in opposite directions in the current-carrying rings on both sides of the ion trap, without the need to increase additional cooling particles or laser sources, and without the need for a complex cooling mechanism, thereby enabling the process of reducing the second-order Doppler effect to become simple.

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

[0092] 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 size of the gradient magnetic field.

[0093] The number of turns of the energized coil is one of the factors that determine the strength of the magnetic field. The more the number of 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 ring, 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 to enable the current-carrying ring to generate a larger magnetic field strength, thereby more effectively regulating 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 to reduce 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 intensity provided by the current source to the current-carrying ring, the controller can adjust the size of the generated gradient magnetic field. Increasing the current value will generate a stronger magnetic field, thereby increasing the strength of the gradient magnetic field, and vice versa.

[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 will generally result in a wider range of magnetic field action, which is suitable for applications that require larger space control; while a smaller radius will result in a more concentrated magnetic field, thereby producing a stronger control effect on the central region of the ion group.

[0096] In the embodiments of the present application, one of the number of turns of the energized coil, the current value of the excitation current, and the radius of the current-carrying ring can be adjusted to adjust the gradient magnetic field. 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 to optimize the ion control effect. For example, in the case of ion population deviation or micro-motion, the compensation system can generate a more suitable 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 embodiments, 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, the compensation system can flexibly control the strength and distribution of the gradient magnetic field, thereby achieving control of the ion position and motion state.

[0098] According to some embodiments of the present application, a plurality of independently controllable energized coils are wound on each current-carrying ring. Adjusting the number of turns of the energized coil of the current-carrying ring includes:

[0099] Controlling the number of energized coils through which the current source passes the excitation current to adjust the number of turns of the energized coil.

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

[0101] By adjusting the number of turns of the energized coil, the required electromagnetic field can be generated under different experimental conditions. For example, increasing the number of turns of a specific energized coil will result in a stronger gradient magnetic field, thereby strengthening the influence on ion motion.

[0102] In some embodiments, a plurality of independently controllable energized coils are wound on each current-carrying ring, which can achieve 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 while the magnetic field on the other side is weakened, thereby forming the desired gradient magnetic field.

[0103] In the above embodiments, a plurality of independently controllable energized coils are wound on each current-carrying ring, which can more flexibly adjust the strength 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 to adjust the number of turns of the energized coil, thereby effectively changing the magnetic field strength 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 sub-current-carrying ring has a different radius, and adjusting the radius of the current-carrying ring includes:

[0105] The control current source supplies excitation current to the target radius sub-current-carrying ring to adjust the radius of the current-carrying ring.

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

[0107] The radius difference of each sub-current-carrying ring enables them to cover different spatial regions when generating a magnetic field, producing electromagnetic fields of different intensities. The sub-current-carrying ring with a larger radius produces a wider gradient magnetic field, which is suitable for adjusting the motion of ions in a large range, while the sub-current-carrying ring with a smaller radius can produce a more concentrated gradient magnetic field. In this way, the compensation system of the second-order Doppler shift can achieve efficient adjustment of the gradient magnetic field to meet different experimental needs.

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

[0109] In some embodiments, the way to adjust the radius of the current-carrying ring can be achieved 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, thereby adjusting 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 their magnetic field effects, thereby providing stronger constraints on the outer ions; while the current of other sub-current-carrying rings can be reduced to weaken their magnetic field effects, allowing the magnetic field to concentrate in the central region of the ion trap.

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

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

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

[0113] The size of the ion trap is a key factor in determining the gradient magnetic field strength distribution. A larger ion trap requires a stronger gradient magnetic field to cover the entire area, while a smaller ion trap only needs to control the gradient magnetic field in a smaller range. In order to adapt to different sizes of ion traps, the number of turns of the energized coil needs to be adjusted accordingly. A larger ion trap usually requires more turns of the energized coil to enhance the strength of the magnetic field, so that the gradient magnetic field can effectively cover a wider space. Conversely, a smaller ion trap can use fewer turns of the energized coil to meet the gradient magnetic field requirement. By adjusting the number of turns of the energized coil, the gradient magnetic field strength generated can be controlled, thereby achieving effective control of the ion trap.

[0114] The excitation current directly affects the strength of the gradient magnetic field. The larger the excitation current, the stronger the gradient magnetic field generated. For a larger size ion trap, a larger excitation current is usually required to enable the excitation magnetic field to be uniformly distributed throughout the ion trap. Conversely, a smaller size ion trap can adjust the strength of the excitation magnetic field by reducing the excitation current, thereby avoiding excessive excitation magnetic field affecting the stability of the ion beam or introducing unnecessary disturbance. Therefore, selecting the appropriate excitation current size not only meets the size requirements of the ion trap, but also adjusts the accuracy of the excitation magnetic field according to experimental needs.

[0115] The radius of the current-carrying ring determines the spatial distribution range of the gradient magnetic field. For a larger ion trap, a larger radius current-carrying ring is usually required to enable the gradient magnetic field to cover a wider spatial range. Conversely, a smaller ion trap is suitable for using a smaller radius current-carrying ring, which can concentrate the action force of the gradient magnetic field, thereby achieving precise control of the ion center position. The size of the radius of the current-carrying ring is closely related to the size of the ion trap, and by adjusting the radius of the current-carrying ring, the gradient of the gradient magnetic field can be effectively controlled, thereby achieving regulation of the ions.

[0116] In the embodiments of the present application, the number of turns of the energized coil, the size of the excitation current, and the radius of the current-carrying ring need to be considered comprehensively, and by adjusting one or more of the parameters, the purpose of optimizing the magnetic field gradient and ion trapping can be achieved. For example, for a larger ion trap, the number of turns of the energized coil can be increased, and the strength of the excitation current can be increased, so that the gradient magnetic field can uniformly cover the entire ion trap area. For a smaller ion trap, the number of turns of the coil can be reduced and the current can be reduced, thereby obtaining a suitable magnetic field strength and reducing excessive disturbance to the ion state. At the same time, the radius of the current-carrying ring can be adjusted as needed to further optimize the distribution of the gradient magnetic field, so that the gradient magnetic field is concentrated in the core area of the ion group, improving the trapping accuracy of the ions.

[0117] In the above embodiments, by adjusting the number of turns of the energized coil, the size of the excitation current, and the radius of the current-carrying ring, the strength and distribution of the gradient magnetic field can be controlled, and the ion beam control in the ion trap can be optimized. In ion traps of different sizes, by reasonably selecting and adjusting these parameters, the accuracy requirements of ion trap control can be effectively met, the influence of the second-order Doppler frequency shift can be reduced, and the application effect in the fields of quantum computing, quantum simulation, and precision measurement can be improved.

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

[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 the preset spatial range with the midpoint as the reference point is determined.

[0120] Wherein, the midpoint refers to the intermediate position of the line connecting the centers of the two current-carrying rings.

[0121] In the embodiments of the present application, by knowing the distribution of the gradient magnetic field at the midpoint, the gradient magnetic field at any other position within the preset spatial range can be further calculated.

[0122] In some embodiments, the gradient magnetic field generated at any point within the preset spatial range can be obtained by using the principle of symmetry. Assuming that the gradient magnetic field at the midpoint is known, the gradient magnetic field usually has symmetry in space. If the magnetic field distribution at the midpoint is known, the magnetic field strength at other points can be calculated by changing the distance.

[0123] In some embodiments, with reference to Figure 2 , Figure 2 is a schematic diagram of the magnetic field distribution when using multi-physical field simulation COMSOL simulation; wherein, 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 is a schematic diagram of the x-axis magnetic field distribution corresponding to the length R=1m, the number of turns N=100 of the energized coil, and the excitation current I=1A; since the magnetic field distribution at any point in the middle region of the current-carrying ring cannot be obtained by analytical method, COMSOL simulation or matrix laboratory (MATrix LABoratory, MATLAB), mathematical software mathematica programming, etc. 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 embodiments, by knowing the gradient magnetic field distribution at the midpoint, the gradient magnetic field at other positions within the preset spatial range can be obtained by using the spatial distribution rule of the magnetic field, which can improve the efficiency.

[0125] It should be understood that although the steps in the flowcharts involved in the above embodiments are shown in sequence according to the arrows, the steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, the execution of the steps is not strictly limited in sequence, and the steps can be executed in other orders. Moreover, at least some of the steps in the flowcharts involved in the above embodiments can include multiple steps or multiple stages, which are not necessarily executed at the same time, but can be executed at different times, and the execution order of the steps or stages is not necessarily sequential, but can be alternately executed with at least part of other steps or steps or stages in other steps.

[0126] Based on the same inventive concept, the embodiments of the present application also provide a second-order Doppler frequency shift compensation device for implementing the above-mentioned second-order Doppler frequency shift compensation method. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme described 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 described above, which will not be repeated here.

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

[0128] The compensation module 201 is configured to, in the case of a multi-ion system of the ion trap, control the current source to pass excitation currents with opposite flow directions in 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 center line 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 comprises:

[0130] The adjustment module 202 is configured to adjust at least one of the number of turns of the energized coils of the current-carrying rings, the current value of the excitation currents, and the radius of the current-carrying rings, so as to adjust the size of the gradient magnetic field.

[0131] According to some embodiments of the present application, the adjustment module 202 is specifically configured to control the number of energized coils through which the current source passes the excitation currents, 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 configured to control the current source to pass the excitation currents to the sub-current-carrying rings with the target radius, so as to adjust the radius of the current-carrying rings.

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

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

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

[0136] The second determining module 204 is configured to determine, 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 the reference point.

[0137] The above-mentioned modules in the compensation device for the second-order Doppler shift can be realized by software, hardware, or a combination thereof, in whole or in part. The above-mentioned modules can be embedded in or independent of the processor in the electronic device in hardware form, or can be stored in the memory in the electronic device in software form, so as to be called and executed by the processor to perform the operations corresponding to the above-mentioned modules.

[0138] In an exemplary embodiment, an electronic device is provided, which can be a controller, and an internal structure diagram thereof can be as shown in Figure 4 The electronic device includes a processor, a memory, an input / output interface (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 configured 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 operating system and the computer program in the non-volatile storage medium to run. The database of the electronic device is configured to store data in the process of compensating for the second-order Doppler shift. The input / output interface of the electronic device is configured to exchange information between the processor and external devices. The communication interface of the electronic device is configured to communicate with external terminals through a network connection. The computer program is executed by the processor to implement a compensation method for the second-order Doppler shift.

[0139] Those skilled in the art can understand that Figure 4 The structure shown in the above-mentioned figure is only a block diagram of part of the 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. Specifically, the electronic device can include more or fewer components than those 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, which includes a memory and a processor, and the memory stores a computer program. When the processor executes the computer program, the following steps are implemented:

[0141] In the case of a multi-ion system, the current source is controlled to pass 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, the processor, when executing the computer program, also implements the following steps:

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

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

[0145] The number of 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 sub-current-carrying ring having a different radius, and the processor, when executing the computer program, also implements the following steps:

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

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

[0149] Based on the size of the ion trap, the number of turns of the energized coils wound around 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.

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

[0151] Based on the generation of the gradient magnetic field 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 predetermined spatial range with the midpoint as the reference point is determined.

[0152] In one embodiment, a computer-readable storage medium is provided, which stores a computer program, and the computer program, when executed by a processor, implements the following steps:

[0153] In the case of a multi-ion system, the current source is controlled to pass 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, the computer program, when executed by the processor, further implements the following steps:

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

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

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

[0158] In one embodiment, the current-carrying ring includes a plurality of concentrically arranged sub-current-carrying rings, each sub-current-carrying ring has a different radius, and the computer program, when executed by the processor, further implements the following steps:

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

[0160] In one embodiment, the computer program, when executed by the processor, further implements the following steps:

[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 size of the coil radius of the current-carrying ring are determined.

[0162] In one embodiment, the computer program, when executed by the processor, further implements the following steps:

[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 predetermined spatial range with the midpoint as the reference point is determined.

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

[0165] In the case of a multi-ion system, the current source is controlled to pass 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, the computer program, when executed by the processor, further implements the following steps:

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

[0168] In one embodiment, the current-carrying ring is wound with a plurality of independently controllable energizing coils, and the computer program, when executed by the processor, further implements the following steps:

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

[0170] In one embodiment, the current-carrying ring includes a plurality of concentrically arranged sub-current-carrying rings, each sub-current-carrying ring having a different radius, and the computer program, when executed by the processor, further implements the following steps:

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

[0172] In one embodiment, the computer program, when executed by the processor, further implements the following steps:

[0173] Based on the size of the ion trap, the number of turns of the energizing coils 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.

[0174] In one embodiment, the computer program, when executed by the processor, further implements the following steps:

[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 predetermined spatial range with the midpoint as the 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. The computer program can be stored in a non-volatile computer readable storage medium. When the computer program is executed, the processes of the above-mentioned embodiments can be included. Any reference to 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. The non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical storage, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. The volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration but not limitation, the RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The database involved in the embodiments provided in the present application can include at least one of a relational database and a non-relational database. The non-relational database can include a distributed database based on a block chain, etc., without being limited thereto. The processor involved in the embodiments provided in the present application can be a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, an artificial intelligence (AI) processor, etc., without being limited thereto.

[0177] The technical features of the above embodiments can be combined arbitrarily. In order to make the description simple, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combinations of the technical features do not exist contradictory, it should be considered as the scope of the present application.

[0178] The above embodiments only express several implementation ways of the present application, and the description is specific and detailed, but it should not be understood as a limitation to the patent scope of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A system for compensating for second order Doppler shift, characterized by, The system comprises a current source, a controller and two parallel and coaxial current-carrying rings, the two current-carrying rings are arranged on both sides of an ion trap, and a current-carrying coil is wound on each current-carrying ring; the current source is connected with the current-carrying coil wound on each current-carrying ring; the controller is in communication connection with the current source; the current-carrying ring comprises a plurality of concentrically arranged sub-current-carrying rings, and the radius of each sub-current-carrying ring is different; the radius of one of the sub-current-carrying rings is , and the distance between the two current-carrying rings is , wherein R is the length. The controller is configured to control the current source to pass excitation currents in opposite directions through the energized coils of the two current-carrying rings to generate a gradient magnetic field at the midpoint of the line connecting the centers of the two current-carrying rings, and the second-order Zeeman frequency shift generated by the gradient magnetic field is used to compensate for the second-order Doppler frequency shift; and the ion trap is a multi-ion system.

2. The system of claim 1, wherein, A plurality of independently controllable energized coils are wound on each of the current-carrying rings.

3. A method of compensating for second order Doppler shift, characterized by, The method comprises: The control current source passes the excitation current in the opposite direction in the current-carrying ring coil on both sides of the ion trap to generate a gradient magnetic field at the midpoint of the circle center line of the two current-carrying rings; the second-order Zeeman frequency shift generated by the gradient magnetic field is used to compensate the second-order Doppler frequency shift; the current-carrying ring is provided with two, and the two current-carrying rings are parallel and coaxial; the current-carrying ring includes a plurality of concentrically arranged sub-current-carrying rings, and the radius of each sub-current-carrying ring is different; wherein the radius of one of the sub-current-carrying rings is , and the spacing between the two current-carrying rings is , wherein R is the length; the ion trap is a multi-ion system.

4. The method of claim 3, wherein, The method further comprises: Adjusting at least one of the number of turns of the energized coils of the current-carrying rings, the current value of the excitation currents, and the radius of the current-carrying rings to adjust the size of the gradient magnetic field.

5. The method of claim 4, wherein, A plurality of independently controllable energized coils are wound on each of the current-carrying rings, and the adjusting of the number of turns of the energized coils of the current-carrying rings comprises: Controlling the number of energized coils through which the current source passes the excitation currents to adjust the number of turns of the energized coils.

6. The method of claim 4, wherein, The adjusting of the radius of the current-carrying rings comprises: Controlling the current source to pass excitation currents through the sub-current-carrying rings of the target radius to adjust the radius of the current-carrying rings.

7. The method of claim 3, wherein, The method further comprises: Based on the size of the ion trap, determining the number of turns of the energized coils wound on the current-carrying rings corresponding to the ion trap, the size of the excitation currents, and the size of the coil radius of the current-carrying rings.

8. The method of claim 3, wherein, The method further comprises: Based on the generation of the gradient magnetic field at the midpoint of the line connecting the centers of the two current-carrying rings, determining the gradient magnetic field generated at any point within a preset spatial range with the midpoint as the reference point.

Images