Slow atomic beam generator, physics package, physics package for optical lattice clock, physics package for atomic clock, physics package for atomic interferometer, physics package for quantum information processing device, and physics package system

Abstract

A high-temperature tank (116) includes an optical window which transmits a laser (132) and is provided at one end, and a right-angle conical mirror (102) which is provided at the other end, has an opening (106) at the apex and which reflects laser light (132) incident from the optical window towards the one end in an area other than the opening (106). A magnetic field generator (112) generates a magnetic field in the region of intersection of the laser reflected by the right-angle conical mirror (102). A magnetic field gradient relaxation module (130) generates a relaxation magnetic field which relaxes the gradient of the magnetic field generated by the magnetic field generator (112).

Description

[Technical Field]

[0001] The present invention relates to a slow atomic beam generator, a physics package, a physics package for an optical lattice clock, a physics package for an atomic clock, a physics package for an atomic interferometer, a physics package for a quantum information processing device, and a physics package system. [Background technology]

[0002] Optical lattice clocks are atomic clocks proposed in 2001 by Hidetoshi Katori, one of the inventors of this application. Optical lattice clocks confine an atomic population within an optical lattice formed by laser light to measure resonant frequencies in the visible light region, enabling measurements with 18-digit precision, far exceeding the precision of current cesium clocks. Optical lattice clocks have been intensively researched and developed by the inventor's group, as well as by various other groups both in Japan and abroad, and are being developed as next-generation atomic clocks.

[0003] Recent optical lattice clock technologies can be found, for example, in the following Patent Documents 1 to 3. Patent Document 1 describes the formation of a one-dimensional moving optical lattice inside an optical waveguide having a hollow passage. Patent Document 2 describes a mode for setting an effective magic frequency. In fact, magic wavelengths have been determined theoretically and experimentally for strontium, ytterbium, mercury, cadmium, magnesium, and the like. Furthermore, Patent Document 3 describes a radiation shield that reduces the effects of blackbody radiation emitted from surrounding walls.

[0004] Optical lattice clocks measure time with such high precision that a 1 cm difference in altitude on Earth, due to the general relativistic effect of gravity, can be detected as a deviation in the passage of time. Therefore, if optical lattice clocks could be made smaller and more portable for use in the field outside of laboratories, they could be applied to new geodesic technologies, such as underground resource exploration, detection of underground cavities, and magma chambers. By mass-producing optical lattice clocks and deploying them in various locations to continuously monitor temporal variations in gravitational potential, applications such as the detection of crustal movements and spatial mapping of gravitational fields could also be realized. In this way, optical lattice clocks are expected to contribute to society as a new fundamental technology that goes beyond the scope of high-precision time measurement.

[0005] Recently, research has been progressing on precision atomic measurement devices that use slow atoms cooled to near absolute zero by laser light. In such precision measurement devices, it is important to generate a slow atomic beam efficiently with a high flow rate.

[0006] The optical lattice clock mentioned above is one example of a device that could potentially use a slow atomic beam generator, which generates a slow atomic beam. Furthermore, neutral atoms cooled to extremely low temperatures have recently been attracting attention as qubits for quantum computing. Quantum computers that use cold atoms as qubits are less susceptible to the influence of the surrounding environment than those that use other qubits, such as electron spins or nuclear spins in solids or liquids. Therefore, quantum information can be retained for a long time. Furthermore, advantages such as the possibility of increasing the number of qubits using Bose condensation technology are expected.

[0007] Recently, attempts have been made to apply the magneto-optical trap (MOT) method to atoms between a plurality of different energy levels.

[0008] In Non-Patent Document 1, it is stated that for calcium (Ca) atoms, 1 From S0 to excited state 1 Magneto-optical trap using the transition to P1, 1 It is in a metastable state from P13 For atoms that transition to P2, 3 From P2 3 The experiment described here uses a magneto-optical trap that utilizes the transition to the metastable state D3. 3 From P2 level 3 The transition to the D3 level has a narrow natural width, and is expected to have a long lifetime and be able to be cooled to low temperatures.

[0009] In Non-Patent Document 2, it is stated that for ytterbium (Yb) atoms, the ground state 1 From S0 to excited state 1 Magneto-optical trap using the transition to P1, 1 From S0 3 The authors report an experiment in which a magneto-optical trap utilizing a transition to P1 is used in combination with a P1 transition. The natural width of the former transition is wide, while the natural width of the latter transition is narrow. By using these in combination, it is possible to trap atoms with a relatively low magnetic field gradient compared to when using a single transition, which is expected to simplify the device and reduce costs.

[0010] Non-Patent Document 3 discusses the difficulty of realizing two-stage cooling using the same MOT device, since the optimal magnetic fields of each magneto-optical trap are different in two-stage cooling, which achieves a wide range of trapping speeds and low cooling temperatures.

[0011] Here, two-stage cooling will be explained.

[0012] When atoms at each level are trapped by a magneto-optical trap, the acceleration a0 of the trapped atoms is expressed as the following equation (1) according to the adiabatic condition.

number

[0013] Δμ represents the effective magnetic moment, and dB / dz represents the magnetic gradient. The Doppler temperature T of the trapped atom D is written as shown in equation (2) below.

number

[0014] Acceleration a0 and Doppler temperature T D is written as shown in equation (3) below.

number

[0015] From equations (1) and (3), the following equation (4) is derived.

number

[0016] The natural width (γ) of the transition is determined by selecting the transition to be used for atom cooling or atom capture. From this natural width, the Doppler temperature T D However, the maximum acceleration is uniquely given by equation (3), and the magnetic field gradient is uniquely given by equation (1). For example, if you want to shorten the deceleration distance by increasing the magnetic field gradient, you will need to use a transition with a large natural width, which will inevitably result in a high Doppler temperature. Conversely, if you want to lower the Doppler temperature, you will need to use a transition with a small natural width, which will inevitably result in a small magnetic field gradient.

[0017] Considering that the maximum acceleration differs depending on the transition, if we can apply magneto-optical trapping to multiple levels, while realizing the above items (1) and (2) in separate spaces, and provide an appropriate magnetic field gradient according to the level of each atom, we can expect to be able to efficiently generate an atomic beam in an even cooler state. [Prior art documents] [Patent documents]

[0018] [Patent Document 1] Patent No. 6206973 [Patent Document 2] Special Publication No. 2018-510494 [Patent Document 3] Japanese Patent Application Publication No. 2019-129166 [Non-patent literature]

[0019] [Non-Patent Document 1] J.Grunert et.al “Sub-Doppler magneto-optical trap for calcium” Phys.Rev.A 65(2002)041401 [Non-patent document 2] A.Kawasaki et.al “Two-color magneto-optical trap with small magnetic field for ytterbium” J.Phys.B Mol Opt.Phys.48(2015)155302. [Non-patent document 3] Hidetoshi Katori. Tetsuya Ido. Yoshitomo Isoya. and Makoto Kuwata-Gonokami. “Magneto-Optical Trapping and Cooling of Strontium Atoms down to the Photon Recoil Temperature“.Phys.Rev.Lett.82.1116.1999 Summary of the Invention [Problem to be solved by the invention]

[0020] As described in the above Non-Patent Document 3, with the configuration of a conventional MOT device, it was difficult to achieve two-stage cooling using the same MOT device.

[0021] An object of the present invention is to realize, in the same device, a magneto-optical trap for atoms at a certain level and another magneto-optical trap for atoms at a level different from the first level. [Means for solving the problem]

[0022] One aspect of the present invention is a slow atomic beam generating device comprising: a high-temperature vessel including an atom source, an optical window provided at one end thereof for transmitting laser light, and a mirror provided at the other end thereof with an opening at its vertex and for reflecting the laser light incident through the optical window toward the one end at a portion other than the opening; a heater for generating an atomic gas from the atom source within the high-temperature vessel by heating the high-temperature vessel; a magnetic field generating device for generating a magnetic field in a region where the laser light reflected by the mirror intersects; and a magnetic field gradient relaxation module for generating a relaxation magnetic field at the opening which relaxes the gradient of the magnetic field generated by the magnetic field generating device; the slow atomic beam generating device is characterized in that it forms an atomic beam from the atomic gas by utilizing a magneto-optical trap realized by the laser light and the magnetic field, and emits the atomic beam to the outside through the opening.

[0023] According to the above configuration, the magnetic field gradient generated by the magnetic field generator is relaxed by the magnetic field gradient relaxation module at the opening. This creates a strong magnetic field gradient and a weak magnetic field gradient, and different magneto-optical traps are realized by each magnetic field gradient. That is, a magneto-optical trap for atoms at a certain level and another magneto-optical trap for atoms at a different level are realized. According to the above configuration, both can be realized using the same slow atomic beam generator.

[0024] The magnetic field generating device may be an anti-Helmholtz coil that forms a magnetic field gradient, and the relaxation module may be a coil that has a similar shape to the anti-Helmholtz coil and through which a current flows in the opposite direction to that of the anti-Helmholtz coil.

[0025] The magnetic field generating device may be a cylindrical permanent magnet that forms a magnetic field gradient, and the mitigation module may have a shape similar to the cylindrical permanent magnet and be magnetized in the opposite direction to the cylindrical permanent magnet.

[0026] The magnetic field generating device may generate a magnetic field gradient, and the mitigation module may be made of a soft magnet and may absorb magnetic flux therein to mitigate the magnetic field gradient therein.

[0027] The opening may be formed at a location other than on the axis of the laser light.

[0028] The atomic source is, for example, strontium or ytterbium. By using the above configuration, it is possible to generate a slow atomic beam of strontium or ytterbium. Strontium and ytterbium are merely examples, and other elements that have low saturated vapor pressures at room temperature and do not produce sufficient atomic gas may be used. The heater setting temperature may be changed depending on the element used. For example, by setting the heater setting temperature to a temperature at which atomic gas of the element used can be obtained, sufficient atomic gas of such an element can be obtained.

[0029] The high-temperature vessel has, for example, a right-angled circular cone shape or a right-angled quadrangular pyramid shape symmetric about a 2n axis (n=an integer equal to or greater than 2). That is, the high-temperature vessel may have a conical shape or a polygonal pyramid shape.

[0030] One aspect of the present invention is a physics package comprising the slow atomic beam generating apparatus described above and a vacuum chamber surrounding a clock transition space in which the atoms are placed.

[0031] One aspect of the present invention is a physics package for an optical lattice clock, which includes this physics package.

[0032] One aspect of the present invention is a physics package for an atomic clock, which includes this physics package.

[0033] One aspect of the present invention is a physics package for an atom interferometer, which includes the physics package.

[0034] One aspect of the present invention is a physics package for a quantum information processing device for atoms or ionized atoms, characterized in that it includes this physics package.

[0035] One aspect of the present invention is a physics package system including this physics package and a control device that controls the operation of the physics package. [Effects of the Invention]

[0036] According to the present invention, a magneto-optical trap for atoms at a certain level and another magneto-optical trap for atoms at a level different from the first level can be realized in the same device. [Brief explanation of the drawings]

[0037] [Figure 1] 1 is a block diagram showing the overall configuration of an optical lattice clock according to an embodiment. FIG. [Figure 2] 1 is a diagram schematically illustrating the configuration of a slow atomic beam generating apparatus according to a first embodiment. [Figure 3] 1 is a diagram schematically illustrating the configuration of a slow atomic beam generating apparatus according to a first embodiment. [Figure 4] FIG. 2 is a perspective view showing a high-temperature bath and a magnetic gradient relaxation module. [Figure 5] FIG. 2 is a perspective view showing a high-temperature bath and a magnetic gradient relaxation module. [Figure 6] FIG. 10 is a diagram showing the calculation results of the magnetic field distribution. [Figure 7] FIG. 10 is a diagram showing a magnetic field profile. [Figure 8] FIG. 10 is a diagram showing a magnetic field profile. [Figure 9] 1 is a diagram schematically illustrating the configuration of a slow atomic beam generating apparatus according to a first embodiment. [Figure 10] FIG. 1 is a diagram illustrating energy transitions. [Figure 11] FIG. 10 is a diagram schematically illustrating the configuration of a slow atomic beam generating apparatus according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0038] <Configuration of an optical lattice clock> The schematic configuration of an optical lattice clock 10 in which the slow atomic beam generating device according to this embodiment is used will be described with reference to Fig. 1. Fig. 1 is a block diagram showing the overall configuration of the optical lattice clock 10. Here, the optical lattice clock 10 will be used as an example of a device in which the slow atomic beam generating device is used, but of course the slow atomic beam generating device according to this embodiment may also be used in devices other than the optical lattice clock 10.

[0039] The optical lattice clock 10 includes, for example, a physics package 12, an optical system 14, a control system 16, and a PC (Personal Computer) 18.

[0040] The physics package 12 is a device that captures an atomic ensemble, confines it in an optical lattice, and induces a clock transition. The optical system 14 is a device equipped with optical devices such as a laser light source for atom capture, a clock transition excitation laser light source, and a laser frequency control device. In addition to sending laser light to the physics package 12, the optical system 14 receives fluorescent signals emitted by the atomic ensemble in the physics package 12, converts them into electrical signals, and feeds them back to the laser light source to match the atomic resonance frequency. The control device 16 controls the physics package 12 and the optical system 14. The control device 16 controls, for example, the operation of the physics package 12 and the optical system 14, and performs analytical processing such as frequency analysis of clock transitions obtained by measurements. The functions of the optical lattice clock 10 are realized by the mutual cooperation of the physics package 12, the optical system 14, and the control device 16.

[0041] The PC 18 is a general-purpose computer including a processor and memory. The functions of the PC 18 are realized by software being executed by hardware including the processor and memory. An application program that controls the optical lattice clock 10 is installed in the PC 18. The PC 18 is connected to the control device 16 and may control not only the control device 16 but also the entire optical lattice clock 10 including the physics package 12 and the optical device 14. The PC 18 also provides a UI (User Interface) for the optical lattice clock 10. A user can start the optical lattice clock 10, measure time, and check results via the PC 18.

[0042] A system including physics package 12 and the configuration required to control physics package 12 may be referred to as a "physics package system." The configuration required for control may be included in control device 16 or PC 18, or may be included in physics package 12. In addition, some or all of the functions of control device 16 may be included in physics package 12.

[0043] The slow atomic beam generating apparatus according to this embodiment will be described in detail below.

[0044] <Configuration of the slow atomic beam generating device according to the first embodiment> The configuration of the slow atomic beam generation device according to the first embodiment will be described with reference to Fig. 2. Fig. 2 is a diagram schematically showing the configuration of the slow atomic beam generation device 100 according to the first embodiment. Hereinafter, the axis parallel to the longitudinal direction of the slow atomic beam generation device 100 will be referred to as the Z axis.

[0045] The slow atomic beam generating device 100 is broadly divided into a high-temperature section and a room-temperature section, and by forming magnetic fields with locally different gradients, it is possible to realize a magneto-optical trap for atoms at a certain level and another magneto-optical trap for atoms at a different level.

[0046] The high temperature section includes a right-angled conical mirror 102, an optical window 104, an opening 106, a heater 108, a sample 110, a magnetic field generator 112, a thermometer 114, and a high temperature chamber 116.

[0047] The room temperature section includes a flange 118 , a thermal radiation shield 120 , an insulating support rod 122 , a cooling filter window 124 , a vacuum-resistant window 126 , and a vacuum-resistant electrical connector 128 .

[0048] The high temperature section further includes a magnetic field gradient mitigation module 130 .

[0049] The high-temperature bath 116 has a shape that is symmetrical about the Z axis. For example, the high-temperature bath 116 has a shape that is symmetrical about 2n (n = an integer greater than or equal to 2) axes with respect to the Z axis. Specifically, the high-temperature bath 116 has a right-angled conical shape that is symmetrical about 2n (n = an integer greater than or equal to 2) axes. The high-temperature bath 116 may have a cylindrical shape or a polygonal pyramid shape.

[0050] The high-temperature chamber 116 includes a sample 110 serving as an atom source, an optical window 104 at one end through which laser light passes, and a right-angled conical mirror 102 at the other end. A space axially symmetric with respect to the Z axis is formed inside the high-temperature chamber 116, and the right-angled conical mirror 102 is provided on the inner surface thereof so as to face the optical window 104 at one end. If the high-temperature chamber 116 has a shape that is four-fold axially symmetric with respect to the Z axis, a right-angled square pyramidal mirror is provided instead of the right-angled conical mirror 102. The right-angled conical mirror 102 reflects the laser light (laser light 132, described below) incident from the optical window 104 into the space inside the high-temperature chamber 116 toward the optical window 104. An opening 106 is formed at the vertex of the right-angled conical mirror 102. The opening 106 is a hole drilled at the vertex. Since the vertex is located on the Z axis, the opening 106 is also located on the Z axis. As will be described later, the atomic beam is emitted from the opening 106 to the outside of the high-temperature chamber 116 .

[0051] The thermometer 114 is provided on the side of the high-temperature bath 116 and measures the temperature of the high-temperature bath 116. The thermometer 114 is, for example, a thermocouple thermometer or a resistance thermometer using platinum or the like.

[0052] A heater 108 for heating the high-temperature bath 116 and a magnetic field generator 112 for generating a magnetic field are provided on the outer periphery of the high-temperature bath 116. A magnetic field gradient mitigation module 130 is provided inside the magnetic field generator 112. The magnetic field gradient mitigation module 130 will be described in detail later.

[0053] The magnetic field generator 112 generates a magnetic field for trapping atoms using the magneto-optical trapping (MOT) method inside the high-temperature chamber 116. The magnetic field generator 112 may be provided on the outer periphery of the high-temperature chamber 116 or on the inner surface of the thermal radiation shield 120.

[0054] The magnetic field generator 112 is, for example, a coil. The coil is, for example, an anti-Helmholtz coil that has an axisymmetric shape with respect to the Z axis and in which a current flows antisymmetrically with respect to its central axis. A uniform gradient magnetic field is formed by passing a current through the coil. To form a large gradient magnetic field, for example, it is necessary to wind a wire with a large diameter with many turns so that a large current can flow. Of course, other coils may also be used.

[0055] When the set temperature of the high-temperature bath 116 is 250° C. or less, a coated copper wire or the like that can withstand that temperature is used as the coil.

[0056] When the slow atomic beam generating device 100 is used in a high-temperature environment, such as when the set temperature of the high-temperature chamber 116 is 270°C, an uncoated copper wire is used as the coil. For example, a bobbin made of alumina ceramic or the like is used, and grooves are formed in the bobbin to prevent adjacent copper wires from contacting each other, and the copper wire is wound around the bobbin using the grooves as guides.

[0057] As another example, the magnetic field generating device 112 may be a permanent magnet. The permanent magnet may be, for example, a pair of permanent magnets having an axisymmetric ring shape and magnetized antisymmetrically with respect to the central axis. As another example, the permanent magnet may be a permanent magnet having an axisymmetric cylindrical shape that covers the high-temperature bath 116 and magnetized in the radial direction. Of course, permanent magnets other than these may also be used. A uniform gradient magnetic field is formed by the permanent magnet.

[0058] Furthermore, a permanent magnet having a Curie temperature sufficiently higher than the set temperature is used, such as a samarium-cobalt magnet, an alnico magnet, or a strontium ceramic magnet.

[0059] The magnetic field generator 112 forms a quadrupole magnetic field distribution suitable for the right-angled conical mirror 102. The high-temperature chamber 116 may have a right-angled square pyramid shape instead of a right-angled conical shape. That is, a right-angled square pyramid mirror may be used instead of the right-angled conical mirror 102.

[0060] As another example, the magnetic field generator 112 may be 2n (n = an integer of 2 or more) rectangular or saddle-shaped coils of the same shape provided on the side (on the outer circumferential surface of the high-temperature bath 116) surrounding the 2n (n = an integer of 2 or more) axis of rotational symmetry of the high-temperature bath 116. For example, the control device 16 causes currents to flow in opposite directions through the coils facing each other across the 2n axis of rotational symmetry, thereby causing the magnetic field generator 112 to generate a two-dimensional quadrupole magnetic field.

[0061] As yet another example, the magnetic field generator 112 may be 2n square-prism-shaped or arc-prism-shaped permanent magnets (cylindrical permanent magnets with a square or arc-shaped cross section) of the same shape, provided on the side of the high-temperature bath 116 (on the outer circumferential surface of the high-temperature bath 116) surrounding the 2n-th rotational symmetry axis. The permanent magnets are magnetized in an angular direction relative to the symmetry axis (the circumferential direction surrounding the symmetry axis). Furthermore, the magnetization directions of the permanent magnets facing each other across the 2n-th rotational symmetry axis are opposite to each other. This forms a quadrupole magnetic field.

[0062] The heater 108 heats the high-temperature chamber 116 so that it reaches a set temperature. For example, the heater 108 heats a part or the entire high-temperature chamber 116. Heating by the heater 108 transitions the state of the atomic source from a solid phase to a gas phase, thereby generating an atomic gas that is released into the space inside the high-temperature chamber 116. Heating by the heater 108 also prevents the atomic gas from re-condensing when it collides with the optical window 104 or the inner wall of the high-temperature chamber 116. The transition of the state of the atomic source from a solid phase to a gas phase can be achieved not only by the heater 108 but also by ablation using a laser.

[0063] The sample 110 contains an atom source and is housed in a small chamber provided on the side of the inner wall of the high-temperature chamber 116. The sample 110 may be introduced or removed through the opening 106, or by disassembling the slow atomic beam generator and removing the optical window.

[0064] The high temperature bath 116 is made of a material that does not chemically react with the atomic gas at the set temperature and does not alloy with the atomic gas.

[0065] The temperature of the high-temperature chamber 116 is set so that the saturated vapor pressure of the sample 110 is sufficiently higher than the degree of vacuum of the environment in which the sample 110 is placed, and so that the saturated vapor pressure of the heated portion, such as the high-temperature chamber 116, is sufficiently lower. For example, when the atom source is strontium (Sr), the set temperature of the high-temperature chamber 116 is set to 270°C.

[0066] The material of the right-angled conical mirror 102 and the high-temperature chamber 116 is, for example, aluminum, aluminum-coated metal, aluminum-coated insulator, silver, silver-coated metal, silver-coated insulator, SUS (stainless steel), glass with an optical multilayer coating, etc. The insulator is, for example, ceramic (e.g., high-purity alumina) or glass.

[0067] The material of the right-angled conical mirror 102 may be the same as or different from the material of the high-temperature bath 116. For example, if the material of the right-angled conical mirror 102 is the same as the material of the high-temperature bath 116, the surface that functions as the right-angled conical mirror 102 can be mechanically polished to a mirror finish. If the material of the right-angled conical mirror 102 is different from the material of the high-temperature bath 116, the surface that functions as the right-angled conical mirror 102 can be coated with aluminum plating, silver plating, or the like. Alternatively, the surface that functions as the right-angled conical mirror 102 can be coated with an optical multilayer film.

[0068] The right-angled conical mirror 102 and the high-temperature chamber 116 may be made of a material that has a low vapor pressure when heated to a set temperature and that suppresses the amount of gas released under ultra-high vacuum. The right-angled conical mirror 102 and the high-temperature chamber 116 may be made of a material that, when heated to a set temperature, causes the right-angled conical mirror 102 to have sufficient reflectivity for the incident laser light (laser light 132, described below), and that does not chemically react with or alloy with the atomic gas and maintains sufficient reflectivity. The surface of the right-angled conical mirror 102 is polished so that the surface roughness of the right-angled conical mirror 102 is sufficiently small compared to the wavelength of the incident laser light.

[0069] A material (e.g., sapphire) that maintains transparency at a set temperature is used as the material for the optical window 104. A film that can maintain transparency at a set temperature may be formed on the optical window 104 made of sapphire. For example, a titanium oxide alloy / silica-based multilayer laminate film may be formed on the optical window 104 by using electron beam evaporation.

[0070] The thermal radiation shield 120 is installed to prevent heat radiation from reaching components arranged around the slow atomic beam generator 100. The thermal radiation shield 120 is installed to cover the heater 108, the magnetic field generator 112, and the high-temperature chamber 116. In other words, the heater 108, the magnetic field generator 112, and the high-temperature chamber 116 are arranged in a space surrounded by the thermal radiation shield 120. For example, a material with low surface emissivity (e.g., mirror-finished aluminum or mirror-finished stainless steel) is used. Alternatively, multiple thermal radiation shields 120 may be installed in a stacked configuration. For example, when a double sheet is used, the outer sheet can be made of a material with high magnetic permeability, such as permalloy, to function as both a thermal radiation shield and an electromagnetic shield.

[0071] The optical window 104, the cooling filter window 124, and the vacuum-resistant window 126 are arranged on the Z axis in this order. The optical window 104 is provided at one end of the high-temperature chamber 116, facing the right-angled conical mirror 102.

[0072] The material of the vacuum-resistant window 126 is, for example, Pyrex (registered trademark) glass, quartz glass, etc. Furthermore, the surface of the vacuum-resistant window 126 may be coated with a film that can maintain transparency, such as an anti-reflection coating.

[0073] The cooling filter window 124 is coated with a coating that increases the reflectance at the center wavelength of the spectrum of radiation from the high-temperature portion, and is disposed between the optical window 104 and the vacuum-resistant window 126 on the optical path of the laser light incident on the optical window 104 to prevent heat from flowing from the optical window 104 to the vacuum-resistant window 126. An anti-reflection coating [against the laser light incident on the optical window 104] may also be applied to the cooling filter window 124. The material of the cooling filter window 124 is, for example, the same material as that of the vacuum-resistant window 126. Alternatively, a heat-blocking filter may be used instead of the cooling filter window 124.

[0074] The heat insulating support rod 122 is installed from the high-temperature tank 116 to the flange 118. A material with low thermal conductivity is used for the heat insulating support rod 122 in order to prevent heat from flowing from the high-temperature portion to the room-temperature portion, improve the thermal efficiency of the heater in the high-temperature portion, and maintain the temperature stability of the room-temperature portion. For example, magnesia or steatite ceramic is used as the material for the heat insulating support rod 122.

[0075] The vacuum-resistant electrical connector 128 is a hermetic connector for transmitting and receiving electrical signals between a vacuum space and the atmosphere. The vacuum-resistant electrical connector 128 is used, for example, for inputting and outputting signals from the thermometer 114, for supplying current to the heater 108, and for supplying current to the magnetic field generator 112. For ease of explanation, wiring is not shown in FIG. 2.

[0076] The flange 118 is a component for attaching the slow atomic beam generator 100 to a physics package such as an atomic clock device, such as the optical lattice clock 10, an atomic interferometer device, or a quantum computer device that uses atoms as qubits. The physics package includes a vacuum vessel, and the high-temperature chamber 116 of the slow atomic beam generator 100 is used in an ultra-high vacuum environment, and the interior of the high-temperature chamber 116 is maintained at an ultra-high vacuum. For this reason, the flange 118 has a sealing mechanism, such as a metal gasket, for sealing the vacuum. Note that heat may be transferred from the high-temperature portion to the flange 118. To address this, the flange 118 may be provided with a water-cooling mechanism.

[0077] The magnetic field gradient mitigation module 130 will be described below. The magnetic field gradient mitigation module 130 is installed at a position more inward than the magnetic field generator 112 (i.e., at a position closer to the opening 106 than the magnetic field generator 112) and in a narrower area in the Z-axis direction than the magnetic field generator 112, and mitigates the gradient of the magnetic field generated by the magnetic field generator 112 in and around the opening 106. The magnetic field gradient mitigation module 130 is not installed in the area surrounded by the high-temperature bath 116, i.e., in the area where the right-angled conical mirror 102 is formed, but is installed in the high-temperature bath 116. In this way, the laser light 132 is not blocked by the magnetic field gradient mitigation module 130 but enters the right-angled conical mirror 102 and is reflected by the right-angled conical mirror 102.

[0078] A space symmetrical with respect to the Z axis is formed inside the high-temperature chamber 116. In the example shown in Fig. 2, regions A and B indicated by dashed lines are formed. Regions A and B are regions surrounded by the high-temperature chamber 116. Region B is closer to the opening 106 than region A, and region A is farther from the opening 106 than region B.

[0079] The magnetic field generator 112 is designed to form a magnetic field gradient that is as uniform as possible in the space inside the high-temperature bath 116 (i.e., the space including regions A and B). The magnetic field gradient mitigation module 130 is designed to form a magnetic field gradient locally in region B without affecting region A with a magnetic field. In other words, the magnetic field gradient mitigation module 130 is designed to form a magnetic field gradient in region B that is narrower than the entire region including regions A and B in which the magnetic field is formed by the magnetic field generator 112, and is located inside that entire region. For example, the magnetic field gradient mitigation module 130 is provided around the opening 106 with the Z axis as its center, and forms a magnetic field gradient in region B.

[0080] The magnetic field gradient mitigation module 130 may, for example, have a shape similar to that of the magnetic field generator 112 and may be designed to achieve magnetic poles having opposite signs to those formed by the magnetic field generator 112 .

[0081] For example, if the magnetic field generator 112 is an anti-Helmholtz coil with its axis centered on the Z axis, the magnetic field gradient mitigation module 130 is an anti-Helmholtz coil with a similar shape to the anti-Helmholtz coil and is installed around the opening 106 with its axis centered on the Z axis. The direction of current flowing in each coil is set so that current flows in opposite directions through the anti-Helmholtz coil of the magnetic field generator 112 and the anti-Helmholtz coil of the magnetic field gradient mitigation module 130. In other words, the direction of current flowing in each coil is set so that current flows in the anti-Helmholtz coil of the magnetic field generator 112 in the direction opposite to the direction of current flowing in the anti-Helmholtz coil of the magnetic field gradient mitigation module 130.

[0082] As another example, if the magnetic field generating device 112 is a cylindrical permanent magnet magnetized in the radial direction, the magnetic field gradient mitigation module 130 is a cylindrical permanent magnet having a shape similar to that of the cylindrical permanent magnet, but magnetized in the opposite direction to the permanent magnet of the magnetic field generating device 112.

[0083] As another example, the magnetic field gradient mitigation module is a soft magnet with high magnetic permeability, such as permalloy. FIG. 3 shows a slow atomic beam generator using a soft magnet. The magnetic field gradient mitigation module 130a shown in FIG. 3 is a soft magnet. A soft magnet with high magnetic permeability absorbs magnetic flux around it. The absorbed magnetic flux is then mitigated. For example, the magnetic field gradient mitigation module 130a is made of a ring-shaped soft magnet and is disposed at a distance approximately equal to the radius of the center of the quadrupole magnetic field formed by the magnetic field generator 112. The magnetic field gradient mitigation modules made of ring-shaped soft magnets may be disposed so that their axes are parallel to the central axis of the magnetic field generator 112 and their centers coincide with each other.

[0084] 4 shows a specific example of attaching a magnetic gradient mitigation module to the high-temperature bath 116. FIG. 4 is a perspective view showing the high-temperature bath 116 and a magnetic gradient mitigation module 130a made of a soft magnet. A groove 116a surrounding the opening 106 is formed in the high-temperature bath 116. A ring-shaped magnetic gradient mitigation module 130a is fitted into the groove 116a. A magnetic gradient mitigation module 130 made of a ring-shaped permanent magnet may also be fitted into the groove 116a.

[0085] Another specific example is shown in Figure 5. Figure 5 is a perspective view showing a high-temperature bath 116 and a magnetic gradient mitigation module 130a made of a soft magnet. A protrusion 116b is formed around the periphery of the opening 106 in the high-temperature bath 116, surrounding the opening 106. A ring-shaped magnetic gradient mitigation module 130a is fitted into the protrusion 116b. A magnetic gradient mitigation module 130 made of a ring-shaped permanent magnet may also be fitted into the protrusion 116b.

[0086] 6 shows the calculation results of the magnetic field distribution formed by the magnetic field generator 112 and the magnetic field gradient mitigation module 130. Calculation results A1 and A2 are the calculation results of the magnetic field distribution formed by the magnetic field generator 112. Calculation results B1 and B2 are the calculation results when the magnetic field gradient mitigation module 130 consisting of two arranged ring-shaped soft magnets is used, and are the calculation results of the magnetic field distribution formed by the magnetic field generator 112 and the magnetic field gradient mitigation module 130. Calculation results C1 and C2 are the calculation results when the magnetic field gradient mitigation module 130 consisting of a cylindrical soft magnet is used, and are the calculation results of the magnetic field distribution formed by the magnetic field generator 112 and the magnetic field gradient mitigation module 130.

[0087] The calculation results A1, B1, and C1 show a magnetic field map that expresses the magnetic field strength with color tones (shades). The calculation results A2, B2, and C2 show the magnetic field contour lines.

[0088] In the calculation results A1 and A2, for example, at Z = 0 (vertical axis), uniformly spaced contour lines are formed in the radial direction (horizontal axis), indicating the formation of a uniform magnetic field gradient. In contrast, in the calculation results B1, B2, C1, and C2, the same contour lines as in the calculation results A1 and A2 are formed at positions away from the center, but it can be seen that a region with sparse contour lines, i.e., a region with a relaxed magnetic field gradient, is formed near the center.

[0089] Figure 7 shows the magnetic field profiles corresponding to the calculation results B1 and B2. Figure 8 shows the magnetic field profiles corresponding to the calculation results C1 and C2. In Figures 7 and 8 (a) and (c), the vertical axis indicates the magnetic field, and in Figures 7 and 8 (b) and (d), the vertical axis indicates the magnetic field gradient. In Figures 7 and 8 (a) and (b), the horizontal axis indicates the radial distance, and in Figures 7 and 8 (c) and (d), the horizontal axis indicates the Z-axis distance.

[0090] 7 and 8, profile D1 is a magnetic field profile formed by the magnetic field generator 112 and the magnetic field gradient mitigation module 130. Profile D2 is a magnetic field profile formed only by the magnetic field generator 112 without using the magnetic field gradient mitigation module 130. It can be seen that by using the magnetic field gradient mitigation module 130, the magnetic field gradient is mitigated locally.

[0091] As described above, by providing the magnetic field generator 112 and the magnetic field gradient mitigation module 130, a strong magnetic field gradient is formed in region A, and a weak magnetic field gradient is formed in region B. That is, in region B, the strong magnetic field gradient formed by the magnetic field generator 112 is mitigated by the magnetic field gradient mitigation module 130, thereby forming a locally weak magnetic field gradient.

[0092] The operation of the slow atomic beam generating apparatus 100 will be described below with reference to Fig. 2, Fig. 9, and Fig. 10. Fig. 9 is a diagram schematically showing the configuration of the slow atomic beam generating apparatus according to the first embodiment. Fig. 10 is a diagram showing energy transitions.

[0093] 2 and 9, laser light 132 passes through the vacuum-resistant window 126 from outside the slow atomic beam generator 100 and enters the slow atomic beam generator 100. The laser light 132 has circular polarization (e.g., σ+). The laser light 132 that entered the slow atomic beam generator 100 passes through the cooling filter window 124 and the optical window 104, and is reflected twice by the right-angle conical mirror 102 in the high-temperature chamber 116 (see reference numeral 136). The reflected laser light 132 has circular polarization (e.g., σ-) opposite to that of the outward path, passes through the optical window 104, the cooling filter window 124, and the vacuum-resistant window 126, and is emitted to the outside of the slow atomic beam generator 100.

[0094] The laser beam 134 shown in FIG. 2 is a push laser beam, which passes through the vacuum-resistant window 126 from outside the slow atomic beam generator 100 along the X-axis and enters the slow atomic beam generator 100 .

[0095] The high temperature chamber 116 is heated by the heater 108, which heats the atom source, causing the atoms to evaporate and be released into the space inside the high temperature chamber 116. The atomic gas is trapped and cooled inside the high temperature chamber 116 using a magneto-optical trap.

[0096] A gradient magnetic field is formed in the space inside the high-temperature bath 116 (a region including regions A and B) by the magnetic field generator 112, and the magnetic field gradient in region B is relaxed by the magnetic field gradient relaxation module 130. For example, the magnetic field and magnetic field gradient shown in the magnetic field profile D1 shown in FIG. 7 or FIG. 8 are formed.

[0097] A trapping space for trapping atoms is formed inside the high-temperature bath 116 by the reflected laser light 132 and the magnetic field generated by the magnetic field generator 112 and the magnetic field gradient relaxation module 130, thereby realizing a magneto-optical trap (MOT) for trapping atoms.

[0098] This magneto-optical trap will be described in detail with reference to Fig. 10. First, atoms are trapped on the central axis of region A shown in Fig. 2 by a magneto-optical trap that utilizes energy transitions indicated by reference numeral 140. Some of the atoms trapped in region A are transported to region B by laser beam 134, which is a push laser beam, and are then trapped by a magneto-optical trap that utilizes energy transitions indicated by reference numeral 142 in Fig. 10, and are further cooled to a low temperature.

[0099] That is, the ground state 1 From S0 to excited state 1 Magneto-optical trap using the transition to P1, 1 It is in a metastable state from P1 3 For atoms that transition to P2, 3 From P2 3 The slow atomic beam generator 100 realizes both the magneto-optical trapping using the transition to D3 and the metastable state. 3 From P2 level 3 The transition to the D3 level has a narrow natural width, and is expected to have a long lifetime and be able to be cooled to low temperatures.

[0100] The atoms thus captured and cooled using the magneto-optical trap are output from opening 106 to the outside of high-temperature chamber 116 by laser light 134, which is a push laser light. A slow atomic beam is formed from the atoms thus output. An opening is formed on the Z-axis in thermal radiation shield 120, and the slow atomic beam output from high-temperature chamber 116 to the outside of thermal radiation shield 120 is output from the opening formed in thermal radiation shield 120.

[0101] Furthermore, according to the slow atomic beam generating device 100, the entire high-temperature chamber 116, including the optical window 104, is heated in addition to the sample 110. Therefore, even for elements whose saturated vapor pressure is low at room temperature and for which sufficient atomic gas cannot be obtained, sufficient atomic gas can be obtained by increasing the saturated vapor pressure through heating. For example, strontium is used as the atomic source. By heating the high-temperature chamber 116 to approximately 270°C, sufficient atomic gas can be obtained even when strontium is used as the atomic source. Furthermore, by using a magneto-optical trap, a high flow rate of cooled atomic beams can be generated. Note that elements other than strontium may be used as elements having a low saturated vapor pressure at room temperature. For example, ytterbium may be used as the atomic source.

[0102] In addition, the heated high-temperature chamber 116 is surrounded by a thermal radiation shield 120 and a cooling filter window 124, except for the opening 106 through which the slow atomic beam is output, so that the thermal radiation emitted by the high-temperature portion can be suppressed.

[0103] When it comes to miniaturizing the slow atomic beam generator, the length of the insulating support rods 122, which are primarily responsible for heat conduction between the high-temperature section and the room-temperature section, is an important parameter. Magnesia (MgO) is a suitable material for the insulating support rods 122, considering that it produces little outgassing in a UHV environment. From the perspective of heat dissipation, the number of insulating support rods 122 is preferably three. Of course, this number is merely an example, and any number other than three may be used. The high-temperature chamber 116 is preferably made of aluminum, which has high reflectivity and is unlikely to chemically react with atomic gas. Using aluminum, a light metal, as the material makes it possible to reduce the weight of the slow atomic beam generator and also reduces the risk of deformation of the support rods.

[0104] <Configuration of the slow atomic beam generating device according to the second embodiment> The configuration of the slow atomic beam generation system according to the second embodiment will be described with reference to Fig. 11. Fig. 11 is a diagram schematically showing the configuration of a slow atomic beam generation system 200 according to the second embodiment.

[0105] The slow atomic beam generator 200 according to the second embodiment includes a high-temperature tank 202 instead of the high-temperature tank 116 of the slow atomic beam generator 100 according to the first embodiment. Since the configuration of the slow atomic beam generator 200 other than the high-temperature tank 202 is the same as the configuration of the slow atomic beam generator 100, the configuration of the high-temperature tank 202 will be described below, and a description of the configuration other than the high-temperature tank 202 will be omitted. Note that although FIG. 11 shows a magnetic field gradient relaxation module 130a made of a soft magnet as the magnetic field gradient relaxation module, the magnetic field gradient relaxation module 130 may also be used.

[0106] As in the first embodiment, a right-angled conical mirror 102 is provided on the inner surface of the high-temperature chamber 202. In the second embodiment, no opening 106 is formed at the apex of the right-angled conical mirror 102, and a passage 204 extending along the X-axis perpendicular to the Z-axis is formed near the apex. The passage 204 extends along the X-axis and passes through the high-temperature chamber 202.

[0107] As in the first embodiment, a gradient magnetic field is formed in the internal space of the high-temperature bath 202 (an area including areas A and B) by the magnetic field generating device 112, and the magnetic field gradient in area B is relaxed by the magnetic field gradient relaxation module 130a (or magnetic field gradient relaxation module 130).

[0108] By irradiating the optical lattice light beam into the passage 204 and slightly changing the wavelength of the optical lattice light beam, the optical lattice can be made to move in the direction of travel of the optical lattice light beam. Atoms captured in region B can be moved within the passage 204 by this moving optical lattice. The atoms moved within the passage 204 are output to the outside through the opening 206. The atoms output in this way form a slow atomic beam.

[0109] According to the second embodiment, similar to the slow atomic beam generation system 100 according to the first embodiment, two-stage cooling can be realized by the same slow atomic beam generation system 200. Furthermore, according to the second embodiment, there is an advantage that the laser light 132 used for the magneto-optical trap does not leak to the outside through the opening 106.

[0110] <Physics Package 12 Configuration> The physics package 12 of the optical lattice clock according to this embodiment will be described below. The physics package 12 includes the slow atomic beam generation device 100 according to the first embodiment, a vacuum chamber surrounding the clock transition space in which the atoms are placed, and a mechanism for realizing magneto-optical trapping and clock transition within the vacuum chamber 6. The operation of the physics package 12 will be described below.

[0111] In the physics package 12, the inside of the vacuum chamber is evacuated. A slow atomic beam, sufficiently decelerated by the slow atomic beam generator 100, is emitted from the slow atomic beam generator 100 and reaches a magneto-optical trapping device (MOT device) in the vacuum chamber. Within the MOT device, a magnetic field with a linear spatial gradient is formed around a trapping space where atoms are trapped, and MOT light is irradiated. As a result, atoms are trapped in the trapping space. The slow atomic beam that reaches the MOT device is decelerated in the trapping space, thereby trapping the atomic ensemble in the trapping space. Furthermore, an optical lattice light beam is incident on the trapping space and reflected by an optical resonator installed in the vacuum chamber, thereby forming an optical lattice potential in which standing waves are connected in the direction of propagation of the optical lattice light beam. The atomic ensemble is trapped in the optical lattice potential.

[0112] By slightly changing the wavelength, the optical lattice can be moved in the direction of the optical lattice beam. This moving optical lattice moves the atomic ensemble to the clock transition spectroscopy region. As a result, the clock transition space deviates from the beam axis of the slow atomic beam.

[0113] In the clock transition space, atoms are irradiated with laser light with controlled optical frequency, and high-precision spectroscopy of the clock transition (i.e., the atomic resonance transition that serves as the clock reference) is performed to measure the atom's unique and invariant frequency. This realizes an accurate atomic clock. Note that if there is no need to move the atomic ensemble from the trapping space to the clock transition space, spectroscopy can be performed in the trapping space.

[0114] To improve the accuracy of atomic clocks, it is necessary to eliminate perturbations surrounding the atoms and accurately read out their frequency. Particularly important is the elimination of frequency shifts caused by the Doppler effect due to the thermal motion of atoms. In optical lattice clocks, atoms are frozen in an optical lattice created by the interference of laser light in a space sufficiently small compared to the wavelength of the clock laser. However, within the optical lattice, the frequency of the atoms shifts due to the laser light that forms the optical lattice. Therefore, by selecting a specific wavelength and frequency known as the "magic wavelength" or "magic frequency" for the optical lattice light beam, the influence of the optical lattice on the resonant frequency is eliminated.

[0115] The light emitted as a result of the clock transition is received by the optical system 14 and subjected to spectral processing by the control unit 16 to determine the frequency.

[0116] Instead of the slow atomic beam generation system 100 according to the first embodiment, a slow atomic beam generation system 200 according to the second embodiment may be used.

[0117] In the above description, an optical lattice clock has been used as an example. However, those skilled in the art will recognize that the technology of each embodiment can be applied to devices other than optical lattice clocks. Specifically, the technology can also be applied to atomic clocks other than optical lattice clocks, or to atomic interferometers, which are interferometers using atoms. For example, a physics package for an atomic clock or a physics package for an atomic interferometer may be configured, including a slow atomic beam generator according to the embodiment and a vacuum chamber. The present embodiment can also be applied to various quantum information processing devices for atoms or ionized atoms. A quantum information processing device is a device that performs measurement, sensing, and information processing using the quantum state of atoms or light. Examples of such devices include atomic clocks, atomic interferometers, magnetic field meters, electric field meters, quantum computers, quantum simulators, quantum repeaters, and the like. By utilizing the technology of the embodiments, physics packages for quantum information processing devices can be made compact and portable, similar to physics packages for optical lattice clocks. Note that in such devices, the clock transition space may be treated simply as a space where clock transition spectroscopy occurs, rather than as a space intended for time measurement.

[0118] In these devices, by using the slow atomic beam generating apparatus according to each embodiment, it is possible to use elements for which the saturated vapor pressure is low at room temperature and for which sufficient atomic gas cannot be obtained, and it is also possible to make these devices smaller and more portable.

[0119] In the above description, specific embodiments have been shown to facilitate understanding, but these are merely examples of embodiments, and various other embodiments are possible. [Explanation of symbols]

[0120] 10 Optical lattice clock, 12 Physics package, 14 Optical system, 16 Control system, 100,200 Slow atomic beam generator, 102 Right-angle conical mirror, 104 Optical window, 106 Aperture, 108 Heater, 110 Sample, 112 Magnetic field generator, 116 High-temperature chamber, 120 Thermal radiation shield, 130,130a Magnetic field gradient relaxation module, 132,134 Laser light.

Claims

1. a high-temperature vessel including an atom source, an optical window provided at one end thereof for transmitting laser light, and a mirror provided at the other end thereof, the mirror having an opening at its apex, and reflecting the laser light incident through the optical window toward the one end at a portion other than the opening; a heater that heats the high-temperature tank to generate atomic gas from the atom source within the high-temperature tank; a magnetic field generating device that generates a magnetic field in a region where the laser beams reflected by the mirror intersect; a magnetic field gradient relaxation module that generates a relaxation magnetic field at the opening to relax the gradient of the magnetic field generated by the magnetic field generating device; Including, forming an atomic beam from the atomic gas by utilizing a magneto-optical trap realized by a laser beam and a magnetic field, and emitting the atomic beam to the outside through the opening; A slow atomic beam generating device characterized by:

2. A high-temperature vessel including an atom source, an optical window provided at one end for transmitting laser light, and a mirror having an opening formed at a position other than on the axis of the laser light, and reflecting the laser light incident through said optical window toward said one end at a portion other than said opening; a heater that heats the high-temperature tank to generate atomic gas from the atom source within the high-temperature tank; a magnetic field generating device that generates a magnetic field in a region where the laser beams reflected by the mirror intersect; a magnetic field gradient relaxation module that generates a relaxation magnetic field at the opening to relax the gradient of the magnetic field generated by the magnetic field generating device; Including, forming an atomic beam from the atomic gas by utilizing a magneto-optical trap realized by a laser beam and a magnetic field, and emitting the atomic beam to the outside through the opening; A slow atomic beam generating device characterized by:

3. 3. The slow atomic beam generating apparatus according to claim 1, the magnetic field generating device is an anti-Helmholtz coil that forms a magnetic field gradient; The relaxation module has a shape similar to that of the anti-Helmholtz coil, and is a coil through which a current flows in the opposite direction to that of the anti-Helmholtz coil. A slow atomic beam generating device characterized by:

4. 3. The slow atomic beam generating apparatus according to claim 1, the magnetic field generating device is a cylindrical permanent magnet that forms a magnetic field gradient; The mitigation module has a shape similar to that of the cylindrical permanent magnet and is magnetized in the opposite direction to that of the cylindrical permanent magnet. A slow atomic beam generating device characterized by:

5. 3. The slow atomic beam generating apparatus according to claim 1, the magnetic field generating device forms a magnetic field gradient; The relaxation module is made of a soft magnet and absorbs magnetic flux therein to relax the magnetic field gradient therein. A slow atomic beam generating device characterized by:

6. 6. The slow atomic beam generating apparatus according to claim 1, the atomic source is strontium; A slow atomic beam generating device characterized by:

7. 6. The slow atomic beam generating apparatus according to claim 1, the atomic source is ytterbium; A slow atomic beam generating device characterized by:

8. 8. The slow atomic beam generating apparatus according to claim 1, The high-temperature tank has a right-angled conical shape symmetrical about a 2n axis (n = an integer of 2 or more). A slow atomic beam generating device characterized by:

9. 8. The slow atomic beam generating apparatus according to claim 1, The high-temperature tank has a right-angled quadrangular pyramid shape. A slow atomic beam generating device characterized by:

10. The slow atomic beam generating device according to any one of claims 1 to 9, a vacuum chamber surrounding a clock transition space in which atoms are placed; Including, A physics package characterized by:

11. 11. A physics package comprising: A physics package for optical lattice clocks.

12. 11. A physics package comprising: A physics package for an atomic clock.

13. 11. A physics package comprising: A physics package for an atom interferometer, comprising:

14. 11. A physics package comprising: A physics package for a quantum information processing device for atoms or ionized atoms, characterized in that:

15. The physics package of claim 10; a control device for controlling the operation of the physics package; A physical packaging system including:

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