Atom trap device, atom cooling device, polarization device, optical grating clock, quantum computer, coil, atom trap method, atom cooling method and polarization method

Abstract

To provide a device which reduces a leakage magnetic field in the vicinity of a magnetic trap as further as possible.SOLUTION: An atom trap device for trapping an atom comprises an atom trap section to which a beam of an atomic gas is incident. The atom trap section includes a plurality of optical elements forming a laser beam group and a magnetic field generation section. The magnetic field generation section includes at least two spiral coils and is configured in such a manner that a tip is made thinner and a winding density becomes coarser as it moves forward in a direction in which an atom is guided. The spiral coils are disposed oppositely in such a manner that an interval therebetween becomes narrower as they move forward in the direction in which the atom is guided. A taper solenoid coil generates a magnetic field which optimizes the guide of an atom and laser cooling during the guide by adjusting a component of the magnetic field generated by the spiral coil in a direction in which the atom is guided.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to an atomic trap device, an atomic cooling device, a spectroscopic device, an optical lattice clock, a quantum computer, a coil, an atomic trapping method, an atomic cooling method, and a spectroscopic method.

Background Art

[0002] As a method for trapping (capturing) atoms in space, a magneto-optical trap (hereinafter also referred to as "MOT") is known (see, for example, Non-Patent Documents 1 and 2). Hereinafter, the principle of MOT will be outlined.

[0003] MOT realizes the cooling and trapping of atoms by utilizing the frictional force of laser cooling and the restoring force generated by the Zeeman effect due to a quadrupole magnetic field. In MOT, a quadrupole magnetic field is generated using an anti-Helmholtz coil (two coils with currents flowing in opposite directions). A pair of laser lights facing each other from three directions orthogonal to each other is irradiated so that the vicinity of the intersection of the laser lights is centered. The strength of this quadrupole magnetic field is 0 at the center of the anti-Helmholtz coil and increases as it moves away from the center. The resonance frequency of the atom undergoes a large Zeeman shift as it moves away from the center due to this quadrupole magnetic field. At this time, by appropriately selecting the polarization of the laser light, a restoring force in which the radiation pressure is directed toward the origin is generated. Thereby, laser-cooled atoms can be trapped. The region where atoms are trapped by this method is called the MOT region.

[0004] Another background art of the present invention is an optical lattice clock. The optical lattice clock is an atomic clock proposed by the inventor in 2001. High-precision atomic clocks not only support the development of science and technology through precise measurement, but also play an important role as a basic system that supports modern society, such as the construction of satellite-mounted navigation systems and large-capacity high-speed communication networks. Since 1967 when "second" was defined by the transition frequency of the microwave transition of cesium atoms, cesium atomic clocks have been used as the standard for time and frequency for half a century. During this period, cesium atomic clocks have increased their accuracy by an order of magnitude every 10 years with the introduction of laser cooling technology and the development of atomic fountain clocks, and now achieve an uncertainty of approximately 15 digits and are shared worldwide as International Atomic Time.

[0005] On the other hand, in recent years, with the rapid development of optical frequency control technologies represented by optical frequency combs, narrow linewidth laser light sources, and optical fiber frequency transmission, the research of atomic clocks has been shifting to the development of optical clocks based on atomic transitions in the optical frequency region. The accuracy of a clock is proportional to the reference frequency. Therefore, optical clocks based on optical frequencies enable even higher precision by several orders of magnitude compared to cesium clocks based on microwaves.

[0006] The optical lattice clock is an atomic clock proposed by the inventor in 2001, which can achieve high accuracy in a short time by using the resonance frequency in the optical region of millions of atoms confined in an optical lattice generated by laser light. The optical lattice clock is positioned as a next-generation atomic clock that can achieve an accuracy of 18 digits, far exceeding that of cesium clocks, with an average time as short as a few seconds.

[0007] Generally, the principle of an optical atomic clock is to irradiate laser light on atoms and control the optical frequency of the laser light so as to always resonate with the resonance transition of the atoms that serve as the reference of the clock, thereby realizing the atomic-specific and invariant frequency or time. On the other hand, in order to realize an accurate clock, it is necessary to eliminate the perturbations surrounding the atoms and accurately read their frequencies. Particularly important is the removal of the frequency shift caused by the Doppler effect due to the thermal motion of the atoms.

[0008] An optical lattice clock, which is a type of optical atomic clock, removes the Doppler effect associated with the motion of atoms by confining the atoms in a region narrower than the wavelength of light using an optical trap created by the interference of laser light. On the other hand, when atoms are confined by laser light, the resonance frequency of the atoms is shifted by that laser light. By selecting a specific wavelength called the "magic wavelength" to reduce this, the influence of the optical lattice itself can also be eliminated. In fact, the magic wavelength has been experimentally determined for elements such as strontium, ytterbium, mercury, cadmium, and magnesium.

[0009] To evaluate the accuracy of the realized clock and connect the frequency of the optical lattice clock to international atomic time, the absolute frequency measurement of the resonance transition of strontium atoms was carried out. Subsequently, this measurement was confirmed to be reproducible by follow-up experiments at research institutions in the United States and France. In 2006, an optical lattice clock using strontium atoms was adopted as a "secondary representation of the second" as a strong candidate for the redefinition of the "second". As the accuracy of the optical lattice clock improves, the uncertainty of the cesium clock has come to limit the measurement accuracy. Therefore, in order to perform more accurate evaluations, it has become essential to develop multiple optical lattice clocks and directly compare them.

[0010] The latest technologies of optical lattice clocks are disclosed, for example, in Patent Documents 1 to 3. Patent Document 1 describes a "moving optical lattice" that traps atoms near the lattice points of an optical lattice and moves and transports them along the atomic movement path. Patent Document 2 describes a mode of setting an effective magic frequency. Patent Document 3 describes a radiation shield that reduces the influence from blackbody radiation emitted from the surrounding walls.

[0011] The next step in the application of optical lattice clocks is to develop new applications for high-precision clocks and put them to practical use. If clock measurements can be made with 18 orders of magnitude of precision, for example, a slight difference in height of 1 cm on the ground can be detected as a deviation in the passage of time due to the general relativity effect of gravity. By utilizing such relativistic effects, high-precision clocks can become precision measurement tools that probe new worlds as high-precision gravitational potential meters. For example, if optical lattice clocks can be made portable and used in the field, the possibilities for applications to new geodesic technologies, such as measuring the altitude between remote locations and observing crustal movements, will expand. In addition, by mass-producing highly reliable small clocks and distributing them in various locations to continuously monitor the time fluctuations of gravitational potential, it is conceivable that they can be used to detect crustal movements and map the spatial gravity field. It is expected that clocks will become more compact and portable in the future, contributing to society as a new fundamental technology. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] International Publication No. 2014 / 027637 [Patent Document 2] Special Publication No. 2018-510494 [Patent Document 3] JP 2019-129166 A [Non-patent literature]

[0013] [Non-Patent Document 1] ELRaab et al, M Prentiss, A Cable, S Chu, DE Pritchard, “Trapping of Neutral Sodium Atoms with Radiation Pressure”, Physical. Review. Letters. 59, 2631 (1987).

Non-Patent Document 2

Non-Patent Document 3

Non-Patent Document 4

Non-Patent Document 5

Non-Patent Document 6

Non-Patent Document 7

Non-Patent Document 8

Summary of the Invention

Problems to be Solved by the Invention

[0014] In devices such as atomic clocks and atomic interferometers, in order to continuously perform measurements, it is desirable to continuously supply a cooled atomic gas. However, if the atomic gas is retained in the same place, different processes cannot be applied to the atomic gas. As a result, it becomes difficult to continuously supply the atomic gas to the subsequent device.

[0015] To solve this problem, there is an idea of forming a quasi-three-dimensional quadrupole magnetic field having a magnetic field distribution in which one axial magnetic field gradient is weaker than the other two axial magnetic field gradients (see, for example, Non-Patent Document 4). The quasi-three-dimensional quadrupole magnetic field referred to here is a magnetic field that combines the spherical quadrupole trap required for MOT and a linear quadrupole guide with a bias magnetic field that guides and moves atoms relaxed to a magnetically trapable state. Thereby, atoms laser-cooled in the MOT region and relaxed to a metastable state can be magnetically guided and magnetically trapped at the final trap position.

[0016] As one method for compactly generating such a quasi-three-dimensional quadrupole magnetic field, it is conceivable to use a rod-shaped permanent magnet (hereinafter referred to as a rod magnet).

[0017] However, when a quasi-three-dimensional quadrupole magnetic field is generated by a rod magnet, a problem is that the leakage magnetic field from the rod magnet is large. For example, when attempting to perform spectroscopy at a position about 2 cm away from the rod magnet, the leakage magnetic field in the spectroscopy region becomes several tens of G. Such a strong leakage magnetic field is not preferable because it adversely affects spectroscopy. Therefore, in generating a quasi-three-dimensional quadrupole magnetic field, how to reduce the leakage magnetic field becomes an issue.

[0018] Hereinafter, with reference to FIG. 1, the magnetic field gradient created by the anti-Helmholtz coil will be described. FIG. 1 is a schematic diagram of an anti-Helmholtz coil with a radius R and a center-to-center distance of 1.25R. The direction of the straight line passing through the centers of the two coils is taken as the x-axis. It is assumed that currents of I (A) flow in the two coils in opposite directions. At this time, the magnetic field gradient created by these coils in the x-axis direction is

Equation

[0019] The behavior of the residual magnetic field B at x >> R is B ∝ IR 2 / x 4 represented by. Therefore, miniaturizing the structure of the system contributes to reducing the residual magnetic field.

[0020] On the one hand, if the typical size of the coil is D, the current required to create the same magnetic field gradient is 1 / D 2 suffices. Therefore, the power loss is 1 / D 4 becomes. Thus, miniaturizing the system structure also contributes to power saving.

[0021] However, in order to realize a magneto-optical trap (MOT), in order to laser-cool atoms, about D = 2 cm is required. Therefore, a method is needed to continuously connect a MOT magnetic field that requires a large volume and a compact magnetic field trap.

[0022] An object of the present invention is to generate a compact quasi-three-dimensional quadrupole magnetic field for realizing an MOT and a subsequent magnetic trap, and to reduce the generated leakage magnetic field as much as possible.

Means for Solving the Problems

[0023] In order to solve the above problems, an atomic trap device according to an aspect of the present invention is an atomic trap device for trapping atoms, and includes an atomic trap section into which a beam of atomic gas is incident. The atomic trap section includes a plurality of optical elements that form a laser light group and a magnetic field generation section. The magnetic field generation section includes at least two helical coils and a tapered solenoid coil. The helical coils are configured such that as the atoms travel in the direction in which they are guided, the tips become thinner and the winding density becomes sparser, and the helical coils are arranged to face each other such that the distance between them becomes narrower as the atoms travel in the direction in which they are guided, and the tapered solenoid coil generates a magnetic field that cancels out the component of the magnetic field generated by the helical coils in the direction in which the atoms are guided.

[0024] In a certain embodiment, the magnetic field generation section may form a magnetic field distribution that generates a first region with a larger magnetic field gradient for realizing a magneto-optical trap and a second region with a smaller magnetic field gradient in the guide direction for realizing magnetic guiding of atoms.

[0025] In one embodiment, the magnetic field distribution may be a quasi-three-dimensional quadrupole magnetic field that is a spherical quadrupole magnetic field in the first region and a linear quadrupole magnetic field with a bias magnetic field in the second region.

[0026] An atomic trap device according to an embodiment may include a magnetic field trap that traps guided atoms in a final trap region.

[0027] In one embodiment, the volume of the first region is 1000 mm 3 or more, and the volume of the final trap region may be 1 mm 3 or less.

[0028] In one embodiment, the strength of the leakage magnetic field from the magnetic field generation unit at a position 2 cm or more away from the magnetic field generation unit may be 1 G or less.

[0029] In one embodiment, the direction in which atoms are guided may be the direction in which gravity acts.

[0030] In one embodiment, the helical coil and the tapered solenoid may be formed on a multilayer PCB substrate.

[0031] In one embodiment, the magnetic field generation unit may include a baseball coil.

[0032] In one embodiment, the atoms may be strontium atoms.

[0033] In one embodiment, the atoms may be ytterbium atoms.

[0034] Another aspect of the present invention is an atomic cooling device. This device includes the atomic trap device of the foregoing aspect and a Doppler cooling mechanism.

[0035] Still another aspect of the present invention is a spectroscopic device. This device includes the atomic cooling device of the foregoing aspect and a spectroscopic unit.

[0036] Still another aspect of the present invention is an optical lattice clock. This optical lattice clock includes a physical package, an optical system device, a control device, and a PC. The physical package includes the atomic cooling device of the foregoing aspect and a clock transition excitation unit.

[0037] Still another aspect of the present invention is a quantum computer. This quantum computer includes a physical package, an optical system device, a control device, and a PC. The physical package includes the atomic cooling device of the foregoing aspect and a clock transition excitation unit corresponding to the operation of qubits.

[0038] Still another aspect of the present invention is a coil. This coil is a helical coil configured such that the tip becomes thinner and the winding density becomes sparser as it advances forward.

[0039] Still another aspect of the present invention is an atomic trapping method. This method is a method of trapping atoms using an atomic trapping device including an atomic trapping unit, and includes a step of supplying atoms, a step of magneto-optically trapping the atoms using the atomic trapping unit, and a step of magnetically trapping and guiding the atoms using the atomic trapping unit. The atomic trapping unit includes a plurality of optical elements that form a laser light group and a magnetic field generation unit. The magnetic field generation unit includes at least two helical coils and a tapered solenoid coil. The helical coil is configured such that the tip becomes thinner and the winding density becomes sparser as it advances in the direction in which the atoms are guided, and the helical coils are arranged to face each other such that the distance between them becomes narrower as they advance in the direction in which the atoms are guided, and the tapered solenoid coil generates a magnetic field that cancels out the component of the magnetic field generated by the helical coils in the direction in which the atoms are guided.

[0040] In one embodiment, the magnetic field generation unit may include a baseball coil instead of the helical coils and the tapered solenoid coil.

[0041] Still another aspect of the present invention is an atomic cooling method. This method is a method of cooling atoms using an atomic cooling device including an atomic cooling device and a Doppler cooling mechanism, and includes a step of supplying atoms, a step of magneto-optically trapping the atoms using an atomic trap section, a step of magnetically trapping and guiding the atoms using the atomic trap section, and a step of Doppler cooling the guided atoms using the Doppler cooling mechanism.

[0042] Still another aspect of the present invention is a spectroscopic method. This method is a method of performing spectroscopy using a spectroscopic device including an atomic cooling device and a spectroscopic section, and includes a step of supplying atoms, a step of magneto-optically trapping the atoms using an atomic trap section, a step of magnetically trapping and guiding the atoms using the atomic trap section, a step of Doppler cooling the guided atoms using the Doppler cooling mechanism, and a step of performing spectroscopy using the spectroscopic section.

[0043] In a certain embodiment, the atomic cooling device may include a Sisyphus cooling mechanism instead of the Doppler cooling mechanism, and may include a step of Sisyphus cooling the guided atoms using the Sisyphus cooling mechanism.

Advantages of the Invention

[0044] According to the present invention, it is possible to generate a compact quasi-three-dimensional quadrupole magnetic field that realizes MOT and subsequent magnetic trapping while minimizing the generated leakage magnetic field.

Brief Description of the Drawings

[0045]

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Embodiments for Carrying Out the Invention

[0046] Hereinafter, the present invention will be described with reference to the drawings based on preferred embodiments. The embodiments are illustrative rather than limiting the invention, and not all features and combinations thereof described in the embodiments are necessarily essential to the invention. The same or equivalent components, members, and processes shown in each drawing are denoted by the same reference numerals, and repeated explanations will be omitted as appropriate. In addition, the scales and shapes of the respective parts shown in each figure are set for convenience in order to facilitate the explanation, and are not to be construed restrictively unless otherwise specified. Also, when terms such as "first" and "second" are used in this specification or claims, unless otherwise specified, these terms do not represent any order or importance, but are only for distinguishing one configuration from another. In addition, some of the members that are not important in explaining the embodiments are omitted from the drawings.

[0047] [First Embodiment] Hereinafter, as a first embodiment of the present disclosure, an atomic trap device will be described in detail. First, the flow of processing executed by the atomic trap device according to the embodiment will be described. The continuously performed processing generally includes a first step and a second step. In the first step, an atomic gas is generated from solid atoms. In the second step, the generated atomic gas is trapped in the MOT region, and this atom is further magnetically trapped and guided to the final trap position.

[0048] For example, as external forces for guiding neutral atoms belonging to alkaline earth metals, there are gravity (an external force effective when the mass of the atom is finite), magnetic force (an external force effective when the magnetic moment of the atom is finite), laser radiation pressure (such as laser radiation pressure used in laser deceleration, magneto-optical trap (MOT), or optical molasses), optical dipole force (used in optical dipole force trap, optical lattice, etc.). Here, gravity and magnetic force will be described.

[0049] Alkaline earth metal atoms with two electrons in the outermost shell have a ground state with a spin singlet, and both the angular momentum and the total orbital angular momentum are zero. In this case, it might seem difficult to induce motion in the atomic gas by using magnetic force as an external force. However, due to the optical pumping that occurs during the laser cooling process, 3 it is known that atoms in the P2 state are generated. In the following, this method will be explained using strontium atoms as an example, but this method can also be applied to atoms belonging to Group 2 and Group 2b of the periodic table, such as magnesium atoms and calcium atoms, as well as ytterbium atoms.

[0050] Fig. 2 shows the energy levels of strontium atoms. According to previous studies using strontium atoms, 3 it is known that the lifetime of atoms in the P2 state is 100 seconds or more (see, for example, Non-Patent Document 5). Also, according to another study using strontium atoms, it is known that atoms can be trapped by magnetic force (see, for example, Non-Patent Document 6). Therefore, atoms in the 3 P2 state, which have a long lifetime and are in a metastable state, can be moved by gravity.

[0051] Fig. 3 shows the flow of processing of the atomic trap method according to the embodiment. In the embodiment, the following steps S1 to S3 are executed. S1: Supply slow atoms S2: Magneto-optical trap (MOT) using a quasi-three-dimensional quadrupole magnetic field S3: Magneto-optical guide using a quasi-three-dimensional quadrupole magnetic field

[0052] [Principle of Atomic Trap] Hereinafter, the principle of the atomic trap of the embodiment will be explained using strontium atoms ( 88 Sr) as an example. Here, a three-dimensional coordinate system {x, y, z} is defined. The x-axis, y-axis, and z-axis are axes that are orthogonal to each other. The same operations are possible for other even isotopes (e.g., 86 Sr), or odd isotopes with nuclear spin ( 87 Sr).

[0053] The quasi-three-dimensional quadrupole magnetic field shown in steps S2 to S3 has a magnetic field distribution in which one axial magnetic field gradient is weaker than the other two axial magnetic field gradients. The quasi-three-dimensional quadrupole magnetic field

Number

[0054] In step S2, due to the interaction between the above quasi-three-dimensional quadrupole magnetic field and the 461 nm laser light that resonates between the S0- 1 P1 states, the atoms receive a restoring force and are trapped near the origin, which is the zero magnetic field position. Furthermore, during the above laser cooling, 1 from the 1 P1 state 1 through the 3 D2 state 3 to the

[0055] In step S3, 3 among the atoms in the j P2 state with magnetic quantum number m mag being 1 or 2, the atoms are magnetically trapped near the zero magnetic field position of the quasi-three-dimensional quadrupole magnetic field because the weak magnetic field is energetically stable. The magnetic interaction potential U [Number] g is the g-factor (when the atomic state is 3 in the P2 state, g = 3 / 2), and μ B is the Bohr magneton.

[0056] Also, the magnetic force F acting on the atom mag is expressed by the following formula (2). [Number]

[0057] For the atom, a gravitational force (F = mg) acts in the y direction. If the gravitational force is larger than the y-component of the magnetic force F at the zero magnetic field position, the atom will move in the y direction (i.e., the direction in which the gravitational force acts) from the zero magnetic field position due to the gravitational force. The atom is trapped at the final trap position within the final trap region by the magnetic field trap. Preferably, the volume of the MOT region (magneto-optical trap region) is 1000 mm mag or more, and the volume of the final trap region is 1 mm 3 or less. 3

[0058] When the atom used as the sample is in the state with magnetic quantum number m j = 2 88 and is a Sr atom, the magnetic force that balances the gravitational force with the gravitational coefficient taken as 9.8 m / s 2 is obtained by a magnetic field with a magnetic field gradient of 5.2 G / cm. That is, on the y-axis, in order to move the atom from the zero magnetic field center by the gravitational force, it is necessary to make the magnetic field gradient from the zero magnetic field center to the trapped position less than 5.2 G / cm. On the other hand, 1 To cool and trap an atom in the S0 state by magneto-optical trap for a time of several milliseconds or more, 3 relax it to the P2 state, and magnetically trap the atom, a magnetic field gradient of 30 - 100 G / cm is preferable (the region of the spherical quadrupole trap at both ends of the quasi-three-dimensional quadrupole magnetic field). A quasi-three-dimensional quadrupole magnetic field with strong anisotropy can satisfy these conditions.

[0059] Next, the generation of a highly anisotropic quasi-three-dimensional quadrupole magnetic field for executing steps S1 to S3 will be described. As described above, when a quasi-three-dimensional quadrupole magnetic field is generated by bar magnets, a problem is that the leakage magnetic field from the bar magnets is large. Assuming that the deceleration distance D of the atoms is D ~ 10 mm, the MOT region needs to have a volume of D 3 ~ 1000 mm 3 . Therefore, the quadrupole magnetic field for realizing the MOT also needs to have a similar volume. On the other hand, after the atoms are laser-cooled, the length d of the region where they are magnetically trapped is about d ~ 1 mm. Therefore, the volume of the quadrupole magnetic field for realizing the magnetic trap is d 3 ~ 1 mm 3 .

[0060] The leakage region of the quadrupole magnetic field is about the coil interval. Therefore, by reducing the region of the magnetic trap, the range of the leakage magnetic field can be narrowed. To realize this, as shown in FIG. 4, two coils 221A and 221B (for example, trapezoidal coils) that become thinner toward the front as the atoms proceed in the direction in which they are guided (y-axis direction) are formed. The coil 221A and the coil 221B have substantially the same shape and dimensions. Consider arranging the coils 221A and 221B so that their intervals become narrower as they proceed in the y-axis direction, and making this an anti-Helmholtz coil. That is, when currents in opposite directions are passed through the coils 221A and 221B arranged in this way, a quadrupole magnetic field is generated. Referring also to FIG. 11, the final trap position is formed about 3 mm inside the coils from the front ends (y = 70 mm) of the coils 221A and 221B (y MT = 67 mm). Let this y coordinate be y MT . Also, the MOT region is formed centered around about 20 mm inside the coils from the rear ends (y = 0 mm) of the coils 221A and 221B (taking this y coordinate y MOT ) (y MOT = 20 mm). The volume of the region formed near y = y MT is d 3 ~ 1 mm 3 , and the volume of the region formed near y = y MOT is D 3~1000 mm 3 By selecting the shapes and sizes of coils 221A and 221B so as to achieve this, it is expected that an MOT region and a magnetic trap region of an appropriate size can be formed.

[0061] However, in the above configuration, when a uniform current is passed through coils 221A and 221B, there is a problem that the magnetic field gradient of the guide portion increases unnecessarily.

[0062] To solve this problem, as shown in FIG. 5, coil 222 whose tip becomes thinner as it progresses in the y-axis direction is configured such that the winding density of the coil becomes sparser as it progresses in the y-axis direction. That is, coil 222 has a helical shape. In the example of FIG. 5, coil 222 is composed of four turns a, b, c, and d. Two such coils 222A and 222B are arranged as 221A and 221B in FIG. 4, respectively. By appropriately selecting the winding density of the coil, it is possible to reduce the volumes of the magnetic guide portion and the trap region while keeping the magnetic field gradient constant.

[0063] When a current is passed through the helical coils of FIG. 5 arranged as in FIG. 4, while there is an advantage that the magnetic field gradient in a plane perpendicular to the y-axis can be made constant, confinement in the y-axis direction occurs. As a result, there is a problem that the movement of atoms is hindered and it has an adverse effect on the measurement in the subsequent stage.

[0064] To solve this problem, a tapered solenoid coil 223 as shown in FIG. 6 is provided. Thereby, the confinement in the y-axis direction caused by the helical coils 223A and 223B can be canceled, and the hindrance to the movement of atoms can be prevented.

[0065] [Specific Configuration of Embodiment] Hereinafter, with reference to FIGS. 7 to 10, an atomic trap device and an atomic trap method according to an embodiment will be described. FIG. 7 is a perspective view showing an atomic trap device 10 according to the embodiment. FIG. 8 is a perspective view showing the atomic trap device 10. FIG. 9 is a view of the atomic trap device 10 as seen from the -z direction. FIG. 10 is a view of the atomic trap device 10 as seen from the y direction. A three-dimensional coordinate system {x, y, z} is defined. The x-axis, y-axis, and z-axis are mutually orthogonal axes. The x direction is the direction in which the atomic beam emitted from the atomic oven travels. The y direction is the direction in which gravity acts.

[0066] The atomic trap device 10 according to the embodiment includes an atomic oven 12, a Zeeman decelerator 14, and an atomic trap section 16. The atomic oven 12, the Zeeman decelerator 14, and the atomic trap device 10 are installed in an ultra-high vacuum environment. In each figure, illustrations of fixtures of each module, viewports for inputting and outputting laser light, vacuum exhaust ports, and vacuum exhaust pumps are omitted.

[0067] The atomic oven 12 includes a sample container, a heater, a capillary nozzle, a thermometer, an electrical connector, and a thermal radiation shield. A sample is placed in the sample container. For example, strontium atoms ( 87 Sr and 88 Sr) are used as the sample. By heating the sample in the sample container with the heater, atoms evaporate and an atomic gas is generated. The capillary nozzle is connected to the sample container. The atomic gas exits through the capillary nozzle as a directed atomic beam. The thermometer is used to measure the temperature of the sample container. The electrical connector is used to supply power to the heater. The thermal radiation shield is used to shield thermal radiation from the heater and the sample container to the outside. As the atomic oven 12, a known atomic oven can be used. The atomic beam emitted from the atomic oven 12 travels to the subsequent Zeeman decelerator 14.

[0068] The Zeeman decelerator 14 includes a bore and a magnetic field generation part installed around the bore, and extends in the x direction. The magnetic field generation part includes, for example, a solenoid coil, and generates a magnetic field along the central axis (x-axis) of the bore extending in the x direction. Here, as an example, the magnetic field generation part generates a magnetic field whose intensity decreases as it moves away from the atomic oven 12. Further, resonant laser light 14b is irradiated into the bore from the direction opposite to the traveling direction of the atomic beam (-x direction). The atomic beam emitted from the atomic oven 12 is irradiated into the bore and travels in the x direction within the bore. The Zeeman decelerator 14, according to the Zeeman deceleration method, by the resonant laser light 14b and the gradient magnetic field formed by the magnetic field generation part, decelerates the speed of the atomic beam with a large initial velocity emitted from the atomic oven 12 to a speed that the subsequent atomic trap device 10 can trap. The hot atomic beam travels through the bore toward the atomic trap device 10 while decelerating according to the Zeeman deceleration method. As the Zeeman decelerator 14, a known Zeeman decelerator can be used.

[0069] In the above embodiment, the atomic beam emitted from the atomic oven was decelerated using a Zeeman decelerator. However, it is not limited to this. For example, if a low-speed atomic beam is to be supplied, a Zeeman decelerator is not necessary.

[0070] The atomic trap part 16 includes a vacuum chamber, and forms a trap region in the vacuum chamber where atoms are trapped. The atomic beam that has traveled from the Zeeman decelerator 14 to the atomic trap part 16 is trapped by the atomic trap part 16. Specifically, the atomic trap part 16 includes a plurality of optical elements that form a laser light group 18 and a magnetic field generation part 22.

[0071] The plurality of optical elements includes, for example, a light source, mirrors such as a λ / 4 mirror 20, and a beam splitter, etc., and irradiates the atomic group with a laser light group 18 from six directions with respect to the zero magnetic field position for the purpose of applying a restoring force due to radiation pressure to the atoms. The laser light group 18 includes a laser light traveling in the x direction on the x-axis, a laser light traveling in the opposite -x direction, a laser light traveling in the y direction on the y-axis, a laser light traveling in the opposite -y direction, a laser light traveling in the z direction on the z-axis, and a laser light traveling in the opposite -z direction. A λ / 4 mirror 20 is installed on the z-axis. The laser light traveling in the -z direction is formed by the laser light traveling in the z direction and the λ / 4 mirror 20. That is, the laser light traveling in the z direction is reflected by the λ / 4 mirror 20, thereby forming the laser light traveling in the -z direction.

[0072] Referring to FIGS. 5 to 10, the magnetic field generation unit 22 will be described. The magnetic field generation unit 22 includes a coil 222A, a coil 222B, and a tapered solenoid coil 223, and generates a quasi-three-dimensional quadrupole magnetic field. The coil 222A and the coil 222B have substantially the same shape and dimensions. The coils 222A and 222B taper as they progress in the direction in which the atoms are guided (y-axis direction). The coils 222A and 222B have a decreasing coil winding density (helical shape) as they progress in the direction in which the atoms are guided. The coils 222A and 222B are arranged to face each other so that the distance between them decreases as they progress in the direction in which the atoms are guided. The coils 222A and 222B are each arranged in a tapered shape with respect to the xy plane formed by the x-axis and the y-axis. The tapered solenoid coil 223 is sandwiched between the coil 222A and the coil 222B, or is arranged outside the coil 222A and the coil 222B.

[0073] The λ / 4 mirror 20 is installed outside the coil so as not to block the laser light traveling in the x direction, the laser light traveling in the -x direction, the laser light traveling in the y direction, and the laser light traveling in the -y direction. In order not to deteriorate the optical characteristics of the λ / 4 mirror 20, it may be fixed at locations other than the light receiving part (for example, at the four corners, etc.). Further, the λ / 4 mirror 20 may be installed so as not to be in direct contact with the magnetic field generating part 22.

[0074] The laser light 28 is a narrow linewidth cooling laser light irradiated from the light source 29, and its wavelength is 2.9 μm. The laser light 28 is irradiated in the +y direction on the y-axis. As a result, the atoms are trapped near the position 30 where the magnetic force, the gravitational force, and the radiation pressure of the laser light 28 are balanced.

[0075] The laser light 28 may be incident from both the +y-axis direction and the -y-axis direction, and the magneto-optical trap cooling of the atoms may be performed at the balance point of the magnetic force and the gravitational force.

[0076] FIG. 11(a) is a plan view of the magnetic field generating part 22 viewed from the +z direction. FIG. 11(b) shows the absolute value of the magnetic field strength on the y-axis and the resultant force of the magnetic force and the gravitational force acting on the atoms. The magnetic field on the y-axis crosses zero around y = 20 mm, and a MOT region is formed around this. A spherical quadrupole magnetic field is formed in this region. Outside the MOT region (the region where the y value is larger than the MOT region), the magnetic field gradient is weak, and a magnetic field guide (magnetic trap region) for the atoms is formed. A linear quadrupole magnetic field with a bias magnetic field is formed in this region. In the MOT region 3 The atoms relaxed to the P2 state move in the +y direction under the resultant force of the magnetic force and the gravitational force. In this system, a potential barrier by a magnetic trap is provided near y = 70 mm, and the final trap position is realized near y = 67 mm.

[0077] Consider the case where a current of 3 A is passed through a coil of 30 turns in the system of FIG. 11(a). In this case, the magnetic field gradient in the x-axis direction near the MOT position is calculated to be about 30 G / cm, and the magnetic field gradient in the y-axis direction is calculated to be about 10 G / cm. From this, it can be seen that MOT can be realized in the system of FIG. 11(a).

[0078] FIG. 12 shows the contour lines of the leakage magnetic field generated in the system of FIG. 11(a). FIG. 12(a) is the y - z plane at x = 0, and FIG. 12(b) is the x - y plane at z = 0. In these figures, the magnetic fields from 1G step to 10G are shown, and those exceeding 10G are shown in white. In both FIGS. 12(a) and (b), the region indicated by the upper thick hatching (a position more than 2 cm away from the magnetic field generation part) has a magnetic field strength of 1G or less, which is a region suitable for spectroscopy. On the other hand, for example, when a quasi - three - dimensional quadrupole magnetic field is formed using a bar magnet, a leakage magnetic field of about 10G is generated at a position about 2 cm away from the bar magnet. This makes spectroscopy difficult. It can be seen that this problem can be solved according to the present embodiment. In FIGS. 12(a) and (b), the spherical quadrupole magnetic field where MOT is realized, the linear quadrupole magnetic field with a bias magnetic field suitable for guiding the magnetic field of atoms, and the final trap position of the atoms are also shown.

[0079] [Implementation of the magnetic field generation part] Hereinafter, an implementation example of the magnetic field generation part of the embodiment will be described with reference to FIG. 13. In the example of FIG. 13, the helical coil (for example, the coil 222 shown in FIG. 5) is manufactured using a multilayer PCB substrate. The body that sandwiches such two multilayer PCBs and indicates the multilayer PCB substrate is made of a heat - conductive metal such as Al or Cu. This enables heat dissipation from the multilayer PCB. The multilayer PCB substrate and the body are provided with holes for passing the necessary optical path.

[0080] As a consideration for implementation, the heat dissipation of the multilayer PCB substrate is considered. If the width of the current path is constant on the PCB substrate, the power loss of the PCB substrate is inversely proportional to the thickness of the copper foil forming the substrate. For example, in the case of the generally widely used copper foil thickness of 35μm, the power loss is estimated to be about 24W. When a copper foil thickness of 105μm is used, the power loss is reduced to about 8W, and an implementation without a problem in heat dissipation is possible. Furthermore, by increasing the copper foil thickness, power consumption can be reduced.

[0081] FIG. 14 shows an example in which the magnetic field generating section is composed of four multilayer PCB substrates A, B, C, and D. The helical coil is formed on the upper and lower multilayer PCB substrates A and C. The tapered solenoid coil is formed on the upper and lower multilayer PCB substrates A and C and on the side multilayer PCB substrates B and D. Substrates A and C are 10-layer PCB substrates having substantially the same pattern. Substrates B and D are double-sided PCB substrates having substantially the same pattern. With this configuration, a 9-turn helical coil and a 9-turn tapered solenoid coil are formed.

[0082] Table 1 shows the coil wiring of the magnetic field generating section formed of a multilayer (10-layer) PCB substrate having layers 1 to 10 in order from the bottom layer. FIG. 15 shows, as an example, the coil wired on the first layer of this multilayer PCB substrate.

Table 1

[0083] [Modification Example] FIG. 16 is a schematic diagram of a modification example of the magnetic field generating section. In the above example, the magnetic field generating section is composed of a helical coil and a tapered solenoid coil. Instead of this, the magnetic field generating section may be configured using a coil having the shape shown in FIG. 16. By flowing a current in the direction of the arrow through the coil of FIG. 16, it is possible to simultaneously realize the formation of a quadrupole magnetic field and the cancellation of the magnetic field in the y-axis direction. The coil of FIG. 16 is called a "baseball coil" because it resembles the seam of a baseball.

[0084] The magnetic field generating section may be configured by combining a helical coil and a tapered solenoid coil with a baseball coil.

[0085] As described above, according to the present embodiment, it is possible to provide an atomic trap device that generates a compact quasi-three-dimensional quadrupole magnetic field that realizes MOT and subsequent magnetic trapping while reducing the generated leakage magnetic field as much as possible.

[0086] [Second Embodiment] The second embodiment of the present disclosure is an atomic cooling device. In order to guide the atomic gas to the subsequent device, 3 it is effective to increase the number of atoms in the P2 state as much as possible, 3 and cool the atoms in the P2 state.

[0087] 3 As a method of increasing the number of atoms in the P2 state, by using a laser with a wavelength of 461 nm 1 S0- 1 a method of relaxing to the P2 state via the D2 state by a magneto-optical trap utilizing the excitation between P1 is exemplified. 1 via the D2 state 3 to relax to the P2 state.

[0088] For further cooling the atoms in the P2 state trapped by the magnetic field, it is conceivable to perform Doppler cooling utilizing the excitation between P2- 3 D3 corresponding to the energy difference of the wavelength of 2.9 μm. Since the transition linewidth during this period is extremely narrow at 57 kHz, a low cooling temperature of several microkelvins can be realized (see, for example, Non-Patent Documents 4 and 7). The achievable cooling temperature during the magnetic field trap is represented by the following formula (3). 3 P2- 3 Here, T

Number

Number

Number

[0089] ​The atomic cooling device according to the second embodiment includes the atomic trap device (for example, the atomic trap device 10) of the foregoing embodiment. In addition to the processes S1 to S3 of the atomic trap device, the atomic cooling device executes the following steps. S4: 3 Cool the atoms in the P2 state with narrow linewidth. S5: Guide the cooled atoms to a subsequent device by a moving optical lattice or an optical dipole guide. At this time, optical pumping may be performed to a third state insensitive to a magnetic field.

[0090] In step S4, 3 for the atoms in the P2 state, 3 P2- 3 Doppler cooling is performed by irradiating laser light with a wavelength of 2.9 μm that resonates between the D3 states. As a result, the temperature of the atoms decreases to about several microkelvins. Further, 3 an optical lattice potential may be introduced into the D3 state, and the cooling efficiency of the atoms may be enhanced using the Sisyphus process (see, for example, Non-Patent Document 8).

[0091] In step S5, an optical dipole guide is used to connect the position where the atoms are finally trapped and the input section (the location where the cooled atoms are input) of the subsequent device. At this time, the cooled atoms may be guided to the subsequent device by optically pumping the cooled atoms into a state insensitive to a magnetic field. For example, using a moving optical lattice technique (see, for example, Patent Document 3), the cooled atoms may be moved from the trapped position to the input section of the subsequent device. The third state is 3 the magnetic sub-level with m j = 0 of the P2 state, 3 the P0 state, or 1 the S0 state.

[0092] According to the present embodiment, magnetically trapped atoms can be effectively cooled.

[0093] In the above embodiment, the magnetically trapped atoms were cooled by Doppler cooling. However, the cooling method is not limited to Doppler cooling. For example, a Sisyphus cooling mechanism may be used instead of the Doppler cooling mechanism.

[0094] [Third Embodiment] The third embodiment of the present disclosure is a spectroscopic apparatus. This spectroscopic apparatus includes the atomic cooling apparatus of the foregoing embodiment and a spectroscopic unit. The spectroscopic unit is installed in a region where the leakage magnetic field from the magnetic field generation unit 22 is sufficiently weak (for example, a region where the leakage magnetic field is less than 1 G). The atoms cooled by the atomic cooling apparatus are guided to the spectroscopic unit for spectroscopy.

[0095] According to the present embodiment, it is possible to provide a spectroscopic apparatus capable of performing spectroscopy in a compact environment with a weak leakage magnetic field.

[0096] The above embodiment is schematically shown in FIG. 18. From the position where the atoms are finally trapped, the atoms 3 are pulled out by the moving optical lattice in the P2 state. Coaxial with this moving optical lattice, 1 S0- 3 a spectroscopic laser for exciting the clock transition of P0 is incident. By the optical pumping laser 1, the atoms 3 are optically pumped to the P0 state, and the starting point of the spectroscopic region is defined. The atoms interact with the spectroscopic laser during movement in the spectroscopic region and 1 time-develop into a superposition state between the S0 state and 3 the P0 state. The optical pumping laser 2 3 optically pumps the atoms in the P0 state 3 to the P2 state, thereby 1 defining the end point of the spectroscopic region by projective measurement of the clock transition of S0- 3 P0. The atom number measurement laser measures the atoms in the P2 state 3 by laser-induced fluorescence of the P2- 3 D3 transition and 3 determines the excitation rate of the P0 state. 3

[0097] According to the present embodiment, it is possible to prevent laser light causing an optical shift of the clock transition and laser-induced fluorescence from entering the spectroscopic region, enabling highly accurate spectroscopic measurement. Further, this embodiment realizes spectroscopic measurement without dead time and without insensitive time.

[0098] ​ The state of the optical pump is arbitrary. For example, the optical pump laser 1 pumps the atoms to the S0 state, and the optical pump laser 2 pumps the atoms in the P0 state to the P2 state. 1 to the S0 state, and by the optical pump laser 2 3 the atoms in the P0 state 3 to the P2 state by optical pumping. Also in this case, the atom number measurement laser measures the atoms in the P2 state by laser-induced fluorescence of the P2-D3 transition and determines the excitation rate of the P0 state. 3 the atoms in the P2 state 3 P2- 3 by laser-induced fluorescence of the D3 transition and 3 determines the excitation rate of the P0 state.

[0099] The spectroscopy laser may be the clock transition laser.

[0100] All of the above methods achieve waste-time-free Rabi spectroscopy of atoms in the spectroscopy region (longitudinal excitation Rabi spectroscopy) and realize a highly accurate and highly stable optical lattice clock.

[0101] [Fourth Embodiment] The fourth embodiment of the present disclosure is an optical lattice clock. This optical lattice clock includes the atom cooling device of the foregoing embodiment.

[0102] FIG. 17 is a functional block diagram of an optical lattice clock 200 according to this embodiment. The optical lattice clock 200 includes a physical package 202, an optical system device 204, a control device 206, and a PC (personal computer) 208. The physical package 202 includes an atom cooling device 2021 and a clock transition excitation unit 2022. The atom cooling device 2021 is the atom cooling device of the foregoing embodiment.

[0103] The physical package 202 is a device that confines a cooled atomic ensemble in an optical lattice and causes a clock transition. The optical system device 204 is a device equipped with optical equipment such as a laser light source for atomic cooling, a laser light source for an atomic trap, a laser light source for exciting a clock transition, and a laser frequency control device. The optical system device 204 not only sends laser light to the physical package 202, but also, after exciting a clock transition by means of Rabi or Ramsey spectroscopy in the physical package 202, measures the electronic state of the atoms by projective measurement. It receives the signal of this projective measurement, converts it into an electrical signal, and performs processes such as feedback to the laser light source so as to match the resonance frequency of the atoms. The control device 206 is a device that controls the physical package 202 and the optical system device 204. The control device 206 performs, for example, operation control of the physical package 202, operation control of the optical system device 204, and analysis processing such as frequency analysis of the clock transition obtained by measurement. The functions of the optical lattice clock 200 are realized by the physical package 202, the optical system device 204, and the control device 206 cooperating with each other.

[0104] The PC 208 is a general-purpose computer including a processor and a memory. The functions of the PC 208 are realized by software being executed by hardware including a processor and a memory. An application program for controlling the optical lattice clock 200 is installed in the PC 208. The PC 208 is connected to the control device 206 and may control not only the control device 206 but also the entire optical lattice clock 200 including the physical package 202 and the optical system device 204. Further, the PC 208 provides a UI (user interface) of the optical lattice clock 200. A user can perform excitation of the optical lattice clock 200, time measurement, result confirmation, etc. via the PC 208.

[0105] In the physical package 202, an atomic ensemble cooled by the atomic cooling device 2021 is moved to the clock transition spectroscopy region of the clock transition excitation unit 2022.

[0106] In the clock transition space, laser light with a controlled optical frequency is irradiated onto atoms to perform high-precision spectroscopy of clock transitions (i.e., resonance transitions of atoms serving as the reference of the clock), and an atomic and invariant frequency is measured. Thereby, an accurate atomic clock is realized.

[0107] To improve the accuracy of an atomic clock, it is necessary to eliminate perturbations surrounding the atoms and accurately read out the frequency. Particularly important is the removal of the frequency shift caused by the Doppler effect due to the thermal motion of the atoms. In an optical lattice clock, atoms are confined by an optical lattice created by the interference of laser light in a space that is sufficiently small compared to the wavelength of the clock laser, thereby quantizing the motion of the atoms. On the other hand, within the optical lattice, the frequency of the atoms is shifted by the laser light forming the optical lattice. Therefore, as the optical lattice light beam, a specific wavelength and frequency called the "magic wavelength" or "magic frequency" are selected to eliminate the influence of the optical lattice on the frequency of the atomic clock transition.

[0108] The light emitted by the clock transition is received by the optical system device 204, spectroscopically processed, etc. by the control device 206, and the frequency is determined.

[0109] According to the present embodiment, a compact optical lattice clock can be provided.

[0110] Fig. 19 schematically shows the above-described embodiment.

[0111] [Fifth Embodiment] The fifth embodiment of the present disclosure is a quantum computer. This quantum computer includes the atomic cooling device of the foregoing embodiment.

[0112] This quantum computer includes a physical package, an optical system device, a control device, and a PC. The physical package includes an atomic cooling device and a clock transition excitation unit. The atomic cooling device is the atomic cooling device of the foregoing embodiment. The clock transition excitation unit is configured to correspond to the operation of quantum bits.

[0113] According to this embodiment, a compact quantum computer with high scalability of qubits can be realized.

[0114] [Sixth Embodiment] The sixth embodiment of the present disclosure is a coil. This coil is a helical coil shown in FIG. 5. That is, this coil is a coil whose tip becomes thinner as it advances forward, and is a helical coil whose winding density becomes sparser as it advances forward.

[0115] According to this embodiment, a compact quasi-three-dimensional quadrupole magnetic field for realizing a MOT and a subsequent magnetic trap can be generated.

[0116] [Seventh Embodiment] The seventh embodiment is an atomic trapping method. This is a method of trapping atoms using an atomic trap device including an atomic oven and an atomic trap section. This method includes a step of generating an atomic gas using the atomic oven, a step of magneto-optically trapping the atoms using the atomic trap section, and a step of magnetically trapping and guiding the atoms using the atomic trap section. The atomic trap section includes a plurality of optical elements forming a laser beam group and a magnetic field generation section. The magnetic field generation section includes at least two helical coils and a tapered solenoid coil. The helical coils are configured such that their tips become thinner and their winding density becomes sparser as they advance in the direction in which the atoms are guided. The helical coils are arranged to face each other such that their distance from each other becomes narrower as they advance in the direction in which the atoms are guided. The tapered solenoid coil generates a magnetic field that cancels out the component of the magnetic field generated by the helical coils in the direction in which the atoms are guided.

[0117] [Eighth Embodiment] The eighth embodiment is an atomic cooling method. This is a method of trapping atoms using an atomic cooling device including the atomic cooling device described in the second embodiment and a Doppler cooling mechanism. This method includes steps of generating an atomic gas using an atomic oven, magneto-optically trapping atoms using an atomic trap section, magnetically trapping and guiding atoms using the atomic trap section, and Doppler cooling the guided atoms using the Doppler cooling mechanism.

[0118] [Ninth Embodiment] The ninth embodiment is a spectroscopic method. This is a method of performing spectroscopy using the atomic cooling device described in the second embodiment. This method includes steps of generating an atomic gas using an atomic oven, magneto-optically trapping atoms using an atomic trap section, magnetically trapping and guiding atoms using the atomic trap section, and Doppler cooling the guided atoms using the Doppler cooling mechanism.

[0119] As described above, the present invention has been described based on embodiments. It is understood by those skilled in the art that these embodiments are examples, and various modifications are possible for each combination of their components and each processing process, and such modifications are also within the scope of the present invention.

[0120] In understanding the technical idea abstracted from the embodiments and modifications, the technical idea should not be construed as being limited to the contents of the embodiments and modifications. The above-described embodiments and modifications are merely examples, and many design changes such as changes, additions, and deletions of components are possible. In the embodiments, regarding the contents that allow such design changes, the notation "embodiment" is added for emphasis. However, design changes are also allowed for the contents without such notation.

Explanation of Reference Numerals

[0121] 10 ··· Atomic trap device, 12 ··· Atomic oven, 14... Zeeman decelerator, 14b... Laser light for Zeeman deceleration, 16... Atomic trap section, 18... Laser light group, 20... λ / 4 mirror, 28... Laser light, 29... Light source, 221A... Trapezoidal coil, 221B... Trapezoidal coil, 222... Helical coil, 222A... Helical coil, 222B... Helical coil, 223... Tapered solenoid coil, S1... Step of supplying slow atoms, S2... Step of performing MOT using a quasi-three-dimensional quadrupole magnetic field, S4... Step of performing magnetic guiding using a quasi-three-dimensional quadrupole magnetic field, S4... Step of performing Doppler cooling, S5... Step of guiding cooled atoms to a subsequent device.

Claims

1. An atomic trap device for trapping atoms, comprising: an atomic trap section into which a beam of atomic gas is incident. The atomic trap section includes a plurality of optical elements that form a laser beam group and a magnetic field generation section. The magnetic field generation section includes at least two helical coils and a tapered solenoid coil. The helical coil is configured such that as the atom travels in the direction in which the atom is guided, the tip becomes thinner and the winding density becomes sparser. The helical coils are arranged to face each other such that the distance between them becomes narrower as the atom travels in the direction in which the atom is guided. The tapered solenoid coil generates a magnetic field that adjusts the component of the magnetic field generated by the helical coil in the direction in which the atom is guided. An atomic trap device characterized by this.

2. The magnetic field generation section forms a magnetic field distribution that generates a first region with a larger magnetic field gradient for realizing a magneto-optical trap and a second region with a smaller magnetic field gradient in the guide direction for realizing magnetic field guiding of atoms. The atomic trap device according to claim 1, characterized by this.

3. The magnetic field distribution is a quasi-three-dimensional quadrupole magnetic field that is a spherical quadrupole magnetic field in the first region and a linear quadrupole magnetic field with a bias magnetic field in the second region. The atomic trap device according to claim 2, characterized by this.

4. The atomic trap device according to claim 3, further comprising a magnetic trap for trapping the guided atoms within a final trap region.

5. The volume of the first region is 1000 mm ３ or more, and the volume of the final trap region is 1 mm ３ or less. The atomic trap device according to claim 4, characterized in that.

6. The atomic trap device according to claim 1, characterized in that the strength of the leakage magnetic field from the magnetic field generation section at a position more than 2 cm away from the magnetic field generation section is 1 G or less.

7. The atomic trap device according to claim 1, characterized in that the direction in which the atom is guided is the direction in which gravity acts.

8. The atomic trap device according to claim 1, characterized in that the helical coil and the tapered solenoid are formed on a multilayer PCB substrate.

9. The atomic trap device according to claim 1, characterized in that the magnetic field generation section includes a baseball coil.

10. An atomic cooling device, comprising: the atomic trap device according to claim 1 and a Doppler cooling mechanism.

11. An atomic cooling device, comprising: the atomic trap device according to claim 1 and a Sisyphus cooling mechanism.

12. A spectroscopic apparatus comprising the atomic cooling device according to claim 10 or 11 and a spectroscopic unit.

13. An optical lattice clock comprising a physical package, an optical system device, a control device, and a PC, wherein the physical package comprises the atomic cooling device according to claim 10 and a clock transition excitation unit.

14. A quantum computer comprising a physical package, an optical system device, a control device, and a PC, wherein the physical package comprises the atomic cooling device according to claim 10 and a clock transition excitation unit corresponding to the operation of a quantum bit.

15. A helical coil configured such that the tip becomes thinner and the winding density becomes sparser as it advances forward.

16. A method for trapping atoms using an atomic trap device having an atomic trap unit, comprising the steps of supplying atoms, magneto-optically trapping the atoms using the atomic trap unit, magnetically trapping and guiding the atoms using the atomic trap unit, wherein the atomic trap unit comprises a plurality of optical elements forming a laser light group and a magnetic field generation unit, the magnetic field generation unit comprises at least two helical coils and a tapered solenoid coil, the helical coil is configured such that the tip becomes thinner and the winding density becomes sparser as it advances in the direction in which the atoms are guided, the helical coils are arranged to face each other such that the distance between them becomes narrower as they advance in the direction in which the atoms are guided, and the tapered solenoid coil generates a magnetic field for adjusting a component of the magnetic field generated by the helical coil in the direction in which the atoms are guided.

17. The atomic trap method according to claim 16, wherein the magnetic field generation unit comprises a baseball coil instead of the helical coil and the tapered solenoid coil.

18. A method for cooling atoms using the atomic cooling device according to claim 10, comprising the steps of supplying atoms, magneto-optically trapping the atoms using the atomic trap unit, magnetically trapping and guiding the atoms using the atomic trap unit, and Doppler cooling the guided atoms using the Doppler cooling mechanism.

19. A method for cooling atoms using the atomic cooling apparatus according to claim 11, comprising: a step of supplying atoms; a step of magneto-optically trapping the atoms using the atom trap section; a step of magnetically trapping and guiding the atoms using the atom trap section; a step of Doppler-cooling the guided atoms using the Zeeman slower cooling mechanism. A method for cooling atoms, characterized by including these steps.

20. A method for spectroscopy using a spectroscopic apparatus comprising the atomic cooling apparatus according to claim 10 and a spectroscopic section, comprising: a step of supplying atoms; a step of magneto-optically trapping the atoms using the atom trap section; a step of magnetically trapping and guiding the atoms using the atom trap section; a step of Doppler-cooling the guided atoms using the Doppler cooling mechanism; a step of performing spectroscopy using the spectroscopic section. A spectroscopic method, characterized by including these steps.

21. A method for spectroscopy using a spectroscopic apparatus comprising the atomic cooling apparatus according to claim 11 and a spectroscopic section, comprising: a step of supplying atoms; a step of magneto-optically trapping the atoms using the atom trap section; a step of magnetically trapping and guiding the atoms using the atom trap section; a step of Doppler-cooling the guided atoms using the Zeeman slower cooling mechanism; a step of performing spectroscopy using the spectroscopic section. A spectroscopic method, characterized by including these steps.

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