Quantum computing device and quantum computer

Abstract

A quantum computing device (1) is provided that includes a permanent magnet device (2) configured to establish magnetic fields having different magnitudes at different positions on a first axis (7) and an ion trap (100) having a first region (14) and a second region (15) arranged one above the other. The ion trap (100) has at least one section (47) that is part of the first region (14) and the second region (15) for accommodating at least one ion crystal. The at least one ionic crystal includes a plurality of trapped ions (6) arranged along the first axis (7). Further, a quantum computer is specified.

Description

[Technical Field]

[0001] The present disclosure relates to quantum computing devices and quantum computers. [Background technology]

[0002] Illustratively, ion traps are configured to trap and manipulate ions for use in quantum computing processes, i.e., to perform computations. For charged trapped ions, interactions, such as Coulomb repulsion, can create bonds between neighboring trapped ions, allowing for entanglement. Thus, to perform quantum computing processes using trapped ions, the trapped ions must be individually controllable and addressable from one another.

[0003] Individual addressing of multiple trapped ions, e.g., qubit registers, is desirable with negligible crosstalk. However, crosstalk between nearby trapped ions is typically a source of error that is difficult to control in quantum computing processes and can hinder the meaningful application, and therefore scalability, of quantum error correction protocols. Summary of the Invention [Problem to be solved by the invention]

[0004] Therefore, a problem to be solved is to specify a quantum computing device with improved controllability, and further, a quantum computer comprising such a quantum computing device is specified. [Means for solving the problem]

[0005] This object is solved by the subject matter of the independent claims. Advantageous embodiments, implementations and further developments are the subject matter of the respective dependent claims.

[0006] According to at least one embodiment, a quantum computing device includes a permanent magnet device configured to establish magnetic fields having different magnitudes for different positions on a first axis. Illustratively, the magnitude of the magnetic fields varies along the first axis for different positions on the first axis.

[0007] The permanent magnet device has a main plane of extension along which the first axis extends. "Extending along the main plane of extension" can mean here and below that the first axis extends in the main plane of extension or that the first axis extends parallel to the main plane of extension.

[0008] The first axis is an imaginary axis. For example, the first axis is an axis of symmetry of the permanent magnet device extending in the main extension plane. That is, the first axis divides the permanent magnet device into two halves in a cross-sectional view along the main extension plane, and the shapes of the two halves are essentially identical. "Essentially identical" means that due to manufacturing tolerances of the permanent magnet device, the areas of the halves, for example the cross sections of the halves, may differ from each other by at most 5% or at most 1%. Alternatively, the first axis has a certain distance to the axis of symmetry of the permanent magnet device.

[0009] The permanent magnet device is configured to generate a multipole magnetic field. In particular, a quadrupole magnetic field is generated at the center of the permanent magnet device, and the magnitude of the magnetic field vanishes, for example, is approximately 0 T. Due to the multipole magnetic field, in particular the quadrupole magnetic field, the magnitude of the magnetic field is different for different positions on the first axis.

[0010] For such permanent magnet devices, the magnitude of the magnetic field varies continuously along the first axis, i.e., for different positions on the first axis starting from the center, and thus the magnitude of the magnetic field for different positions on the first axis is characteristic of the magnetic field gradient along the first axis.

[0011] The magnetic field is represented by the magnetic flux density, and the absolute value of the magnetic flux density corresponds to the magnitude of the magnetic field for a given position on the first axis.

[0012] The components of the magnetic field correspond to the components of the vector, and the vector can point in any direction relative to the first axis. That is, at least some of the vectors of the magnetic field for different positions on the first axis can have different angles relative to the first axis. For example, at least some of the vectors of the magnetic field point in the radial direction of the first axis or in the axial direction of the first axis.

[0013] For example, at least some of the vectors of the magnetic field point in the same radial and / or axial direction of the first axis for different positions on the first axis. Alternatively or additionally, at least some of the vectors of the magnetic field are rotated in the radial direction of the first axis relative to each other.

[0014] The distribution of the magnetic field magnitude is symmetrical about the center of the permanent magnet device along the first axis. Exemplarily, the first axis is divided into two halves by the center of the permanent magnet device, i.e., by an imaginary line perpendicular to the first axis and cutting the first axis into two halves. The magnetic field magnitude has a negative gradient for one half and a positive gradient for the other half. The magnetic field gradient increases along the first axis with respect to the magnetic field magnitude along the first axis, e.g., is approximately linear. That is, the magnetic field gradient is approximately constant along the first axis starting from the center. Due to manufacturing tolerances of the permanent magnet device, a deviation from linearity of up to 5% may exist, exemplarily within the central region.

[0015] According to at least one embodiment, a quantum computing device includes an ion trap having a first region and a second region disposed one above the other. Illustratively, the first region extends along a first level, and the second region extends along a second level. For example, the ion trap has a further major extension plane. The first level and the second level each extend parallel to the further major extension plane.

[0016] A lateral direction is defined as being parallel to said further main plane of extension and a vertical direction is defined as being perpendicular to said further main plane of extension. The first level and the second level are stacked on top of each other in the vertical direction.

[0017] The first and second regions comprise components configured to trap ions at a predetermined trapping potential. The trapping potential can be static or dynamic. For example, trapped ions can be trapped by an electromagnetic field, particularly a radio frequency field for charged trapped ions.

[0018] According to at least one embodiment of the quantum computing device, the ion trap has at least one section that is part of a first region and a second region for containing at least one ionic crystal, the at least one ionic crystal containing a plurality of trapped ions arranged along a first axis, i.e., one ionic crystal is characteristic of one quantum register containing a plurality of trapped ions.

[0019] An ionic crystal can contain or consist of more than two trapped ions, for example, at least 8, at least 20, or at least 100, and / or up to 1000. Each trapped ion is a quantum bit, or qubit for short.

[0020] If the ion trap has more than two sections, the ion trap can accommodate more than two ion crystals. Each section is configured to host one of the ion crystals. The sections do not laterally overlap each other. Every section is part of the first region and the second region. That is, the sections are configured to segment the first region from the second region.

[0021] For example, each trapped ion is represented by a two-level quantum system. When no magnetic field is applied to the two-level quantum system, the two-level quantum system includes a first level and a second level, both levels corresponding to respective eigenstates of each trapped ion. For example, the first level represents the ground state of each trapped ion, and the second level represents an excited state of each trapped ion.

[0022] Illustratively, a magnetic field applied to a two-level quantum system causes the degeneracy of the second level to be lifted and at least two, particularly at least three, sublevels to be generated, such that two, particularly three, transitions from each of the two, particularly three, sublevels to the first level are possible.

[0023] If the trapped ion is an n-level quantum system (n is a natural number greater than or equal to 2), each n-level quantum system contains n levels. For example, when a magnetic field is applied, at least some of the n levels correspond to sublevels. In such an n-level quantum system, multiple transitions are achievable.

[0024] For trapped ions, the magnitude of the magnetic field is different for different positions on the first axis, and therefore the splitting, which depends on the local magnetic field magnitude, is also different for these trapped ions. Therefore, a frequency difference of a particular transition between neighboring trapped ions is also achieved. This frequency difference also results in different resonant frequencies for neighboring trapped ions.

[0025] The total energy of each trapped ion is predetermined by the trapping potential and energy characteristics for each transition, which depends on the magnitude of the magnetic field.

[0026] In particular, permanent magnet devices can be used in combination with ion traps. Due to the different magnitudes of the magnetic field, i.e., the magnetic field gradients of the permanent magnet devices, trapped ions can be individually addressed in frequency space, thereby advantageously realizing improved multi-qubit gates and controlling the coupling of neighboring trapped ions. Furthermore, by tuning the coupling, highly entangled cluster states can be generated, which can be advantageously used for quantum computing.

[0027] Advantageously, permanent magnets exhibit relatively low noise compared to electromagnets, thus allowing high fidelity control of trapped ions.

[0028] In essence, permanent magnet devices are used to obtain large magnetic field gradients experienced by ions trapped in planar or surface ion traps, generating significantly different magnetic fields experienced by ions containing individual spin qubits. Their use in quantum information processing allows for sophisticated addressing in frequency space, thus enabling individual single-qubit rotation with low crosstalk, and introduces effective coupling between ions, thereby enabling multi-qubit gates. While this can also be used in the context of radio frequency (RF) where addressing by focusing radiation is not an option due to its long wavelength, the use of RF fields for qubit control allows for the application of established and economical miniaturization and integration techniques already common even in consumer electronics, simplifying the scaling of ion trap-based quantum computers. The steepness of the magnetic field gradient can be further enhanced by using a yoke to concentrate the magnetic flux. Permanent magnet arrangements, particularly Halbach devices, allow for large magnetic field gradients even when the distance between any surface, including the trap electrodes and the main surface of the magnet, and the trapped ions is large, which is desirable for high-fidelity gates with trapped ions. This, combined with the segmented ion trap described herein, allows flexible trapping configurations to trap several registers for splitting and merging quantum registers, tuning coupling constants between qubits, and generally scaling the capabilities of ion trap-based quantum computers.

[0029] According to at least one embodiment of the quantum computing device, the first region and the second region each comprise at least two end cap electrodes disposed at respective end regions of the ion trap. For example, the ion trap has a first end region and a second end region, the first end region and the second end region being located at opposite ends of the ion trap.

[0030] For example, the first region may have a first end cap electrode in a first end region and a second end cap electrode in a second end region, with the at least one section located therebetween. Furthermore, the second region may have a first end cap electrode in the first end region and a second end cap electrode in the second end region. In this case, the first end cap electrode in the first region and the first end cap electrode in the second region overlap each other laterally, particularly congruently. In this case, the first end cap electrode in the first region and the first end cap electrode in the second region have the same dimensions and are stacked one on top of the other.

[0031] Furthermore, the second end cap electrode of the first region and the second end cap electrode of the second region laterally overlap each other, in particular congruently overlap each other, where the second end cap electrode of the first region and the second end cap electrode of the second region have the same dimensions and are stacked one on top of the other.

[0032] Illustratively, the first end cap electrode in the first region and / or the first end cap electrode in the second region includes two portions. The two portions in the first region and / or the two portions in the second region are spaced apart from one another in a lateral direction, particularly a lateral direction perpendicular to the first axis. Similarly, the second end cap electrode in the first region and / or the second end cap electrode in the second region includes two further portions. The two further portions in the first region and / or the two further portions in the second region are spaced apart from one another in a lateral direction, particularly a lateral direction perpendicular to the first axis.

[0033] The first end cap electrode and the second end cap electrode are each configured to receive a direct current, or dc for short, and are configured to trap target ions along a first axis.

[0034] Illustratively, at least one section is disposed between the first and second end cap electrodes. When the ion trap includes two or more sections, additional cap electrodes, particularly first and second separate cap electrodes in the first and second regions, are disposed between immediately adjacent sections of the first and second regions. That is, the additional cap electrodes are configured to laterally, e.g., axially, separate immediately adjacent sections. Furthermore, the additional cap electrodes are configured to trap ions, particularly ion crystals, in each section along the first axis.

[0035] The dimensions and characteristics described herein above according to the first end cap electrode and the second end cap electrode are also applicable to the first and second separating cap electrodes, respectively, disposed between immediately adjacent sections.

[0036] In particular, by having the first and second separating cap electrodes separate directly adjacent sections, the coupling of directly adjacent ionic crystals can be achieved by a predetermined DC current supplied to the first and second separating cap electrodes, i.e., the potential barrier between directly adjacent ionic crystals along the first axis can be predetermined by the first and second separating cap electrodes.

[0037] Advantageously, such coupling of nearby ionic crystals can enable computational processes compared to quantum computing configurations in which the ionic crystals are not coupled.

[0038] According to at least one embodiment of the quantum computing device, the at least one section comprises a first radio frequency (rf) electrode and a first direct current (dc) electrode in a first region and a second rf electrode and a second dc electrode in a second region, the first rf electrode, the second rf electrode, the first dc electrode, and the second dc electrode having respective main extension planes parallel to the further main extension planes of the first region and the second region, in particular, the main extension planes of the first rf electrode, the second rf electrode, the first dc electrode, and the second dc electrode are parallel to each other.

[0039] The rf electrodes are each configured to be supplied with an alternating current having a frequency range of 200 kHz to 30 GHz, for example, a direct current can be superimposed on the alternating current, and the dc electrodes are each configured to be supplied with a direct current, for example, a direct current can be superimposed on the alternating current.

[0040] It is also possible to replace the dc electrodes with rf electrodes, but in either case the rf and dc electrodes in the first and second regions of a section are configured to trap target ions perpendicular to the first axis.

[0041] In particular, the first rf electrode, the second rf electrode, the first dc electrode, and the second dc electrode are configured to generate the predetermined trapping potential.

[0042] According to at least one embodiment of the quantum computing device, the first rf electrode and the first dc electrode are spaced apart perpendicular to the first axis, and the second rf electrode and the second dc electrode are spaced apart perpendicular to the first axis, e.g., the distance between the first rf electrode and the first dc electrode is equal to the distance between the second rf electrode and the second dc electrode.

[0043] According to at least one embodiment of the quantum computing device, the first RF electrode is disposed above the second DC electrode, and the first DC electrode is disposed above the second RF electrode. For example, the first RF electrode and the second DC electrode overlap each other, particularly congruently, in the lateral direction. For example, the first DC electrode and the second RF electrode overlap each other, particularly congruently, in the lateral direction. Congruently overlapping each other in the lateral direction means here and below that the respective electrodes overlap each other along the vertical direction in a top view.

[0044] For example, the ionic crystal or trapped ion is located vertically between the first and second regions, specifically between the first rf and first dc electrodes and the second rf and second dc electrodes, and laterally, i.e., along the first axis, between the first rf and first dc electrodes and between the second rf and second dc electrodes.

[0045] According to at least one embodiment of the quantum computing device, the first dc electrode, the second dc electrode, the first rf electrode, and the second rf electrode are each formed as a metal film. Illustratively, the metal film comprises gold.

[0046] According to at least one embodiment of the quantum computing device, the metal film has a thickness of at most 30 μm. The metal film may have a vertical thickness of at most 10 μm, at most 5 μm, or at most 1 μm, for example.

[0047] According to at least one embodiment of the quantum computing device, an intermediate region is disposed between the first region and the second region, the intermediate region having a main plane of extension extending laterally, i.e., parallel to the further main plane of extension of the ion trap.

[0048] For example, the intermediate region is configured to vertically separate the first and second regions. For example, the intermediate region has a vertical thickness of at least 1 μm and at most 500 μm. Illustratively, the intermediate region has a vertical thickness of about 125 μm.

[0049] According to at least one embodiment of the quantum computing device, the intermediate region comprises an electrically insulating substrate for the first dc electrode, the second dc electrode, the first rf electrode, and the second rf electrode. Illustratively, the first rf electrode and the first dc electrode are provided on a first major surface of the electrically insulating substrate, and the second rf electrode and the second dc electrode are provided on a second major surface of the electrically insulating substrate opposite the first major surface. Illustratively, the first rf electrode and the first dc electrode, and the second rf electrode and the second dc electrode are applied by physical vapor deposition, such as sputtering, chemical vapor deposition, and / or electroplating processes.

[0050] The electrically insulating substrate is formed from or consists of an electrically insulating material, for example, the electrically insulating material includes or consists of at least one of sapphire, aluminum oxide such as Al2O3, aluminum nitride, silicon, or diamond, or any other suitable material.

[0051] According to at least one embodiment of the quantum computing device, the first region includes a first substrate, and the second region includes a second substrate. For example, in this embodiment, the intermediate layer includes a spacer layer for the first substrate and the second substrate. The spacer layer can be formed from the same materials as described herein above in connection with the intermediate layer being an electrically insulating substrate. Illustratively, the spacer layer does not overlap the first axis in the lateral direction. For example, the spacer layer does not overlap the first RF electrode and the first DC electrode, and the second RF electrode and the second DC electrode in the lateral direction. For example, the spacer layer can be formed from pillars arranged in the edge regions of the first substrate and the second substrate.

[0052] Illustratively, the first substrate is electrically insulating and provides a base for the first RF electrode and the first DC electrode, e.g., the first RF electrode and the first DC electrode are provided on an inner major surface of the first substrate, and the first RF electrode and the first DC electrode are provided on an outer major surface of the first substrate.

[0053] The inner and outer main surfaces of the first substrate are connected by a side surface. Illustratively, the first rf electrode and the first dc electrode are provided on the side surface of the first substrate.

[0054] Illustratively, the second substrate is electrically insulating and provides a base for the second rf electrode and the second dc electrode, e.g., the second rf electrode and the second dc electrode are provided on an inner major surface of the second substrate, and the second rf electrode and the second dc electrode are provided on an outer major surface of the second substrate.

[0055] The inner and outer main surfaces of the second substrate are connected by a side surface. Illustratively, the second rf electrode and the second dc electrode are provided on the side surface of the second substrate.

[0056] The inner major surface of the first substrate faces opposite the inner major surface of the second substrate, and the outer major surface of the first substrate faces away from the outer major surface of the second substrate.

[0057] The inner major surface of the first substrate and / or the outer major surface of the first substrate and / or the inner major surface of the second substrate and / or the outer major surface of the second substrate are largely covered by the respective electrodes. Here, largely means that the respective electrodes cover at least 40%, at least 60%, at least 80%, or at least 90% of the outer major surface of the first substrate and / or the outer major surface of the second substrate. Advantageously, covering most of the outer major surfaces with electrodes allows for particularly good avoidance of charging.

[0058] The first substrate and the second substrate are each formed from or consist of an electrically insulating material, which illustratively includes or consists of at least one of sapphire, aluminum oxide such as Al2O3, aluminum nitride, silicon or diamond, or any other suitable material.

[0059] According to at least one embodiment of the quantum computing device, the at least one permanent magnet arrangement is arranged in the intermediate region, wherein a main extension plane of the at least one permanent magnet arrangement extends transversely, i.e. parallel to the further main extension plane of the ion trap.

[0060] When the intermediate region includes an electrically insulating substrate, the at least one permanent magnet device can be embedded in the electrically insulating substrate. By "embedded" here, it is meant that at least one outer surface of the at least one permanent magnet device is covered by the electrically insulating substrate. Illustratively, all outer surfaces of the at least one permanent magnet device are covered by the electrically insulating substrate.

[0061] When the quantum computing device includes two or more permanent magnet devices, all of the permanent magnet devices can be disposed within the intermediate region. For example, the permanent magnet devices can be laterally spaced apart from one another along the first axis. When the quantum computing device includes two or more sections, at least one of the sections, particularly each section or group of two or more sections, is associated with one of the permanent magnet devices.

[0062] Alternatively, one permanent magnet device surrounds the ion trap and at least one permanent magnet device is in the intermediate region. In both cases, all permanent magnet devices can have the same first axis.

[0063] In this embodiment, the first axis is the axis of symmetry of the permanent magnet device, and the trapped ions can be positioned on the axis of symmetry of the permanent magnet device, which is part of the ion trap.

[0064] When the quantum computing device includes two or more permanent magnet devices, the permanent magnet devices can be configured to provide different magnetic field gradients, thereby achieving regions with relatively high magnetic field magnitudes and regions with relatively low magnetic field magnitudes. Advantageously, non-critical ion transport can be achieved for such different regions, particularly for the regions with relatively low magnetic field magnitudes.

[0065] According to at least one embodiment of the quantum computing device, a soft magnetic material is disposed in the intermediate region, forming a yoke structure, i.e., the soft magnetic material is disposed between the first substrate and the second substrate.

[0066] When the intermediate region includes an electrically insulating substrate, the soft magnetic material can be embedded in the electrically insulating substrate. By "embedded" here, it is meant that at least one outer surface of the soft magnetic material is covered by the electrically insulating substrate. Illustratively, all outer surfaces of the soft magnetic material are covered by the electrically insulating substrate.

[0067] The soft magnetic material and the permanent magnet device can be disposed in the intermediate region, in which case the soft magnetic material and the permanent magnet device are part of the ion trap.

[0068] Alternatively, only the soft magnetic material is located in the intermediate region and the permanent magnet device surrounds the ion trap, in which case only the soft magnetic material is part of the ion trap.

[0069] Alternatively or additionally, the soft magnetic material may not be part of the ion trap, in which case it is located external to the ion trap.

[0070] Additionally or alternatively, at least one permanent magnet device is disposed on a major surface of the electrically insulating substrate and / or a soft magnetic material is disposed on a major surface of the electrically insulating substrate.

[0071] According to at least one embodiment of the quantum computing device, the at least one permanent magnet device is disposed in the first region and / or the second region. Illustratively, the at least one permanent magnet device is embedded in the first substrate and / or the second substrate. Additionally or alternatively, the at least one permanent magnet device is disposed on an inner and / or outer major surface of the first substrate, and / or the at least one permanent magnet device is disposed on an inner and / or outer major surface of the second substrate.

[0072] According to at least one embodiment of the quantum computing device, the soft magnetic material forming the yoke structure is disposed within the first region and / or the second region. Illustratively, the soft magnetic material is embedded in the first substrate and / or the second substrate. Additionally or alternatively, the soft magnetic material is disposed on the inner and / or outer major surfaces of the first substrate and / or the soft magnetic material is disposed on the inner and / or outer major surfaces of the second substrate.

[0073] In essence, the yoke structure is placed in a region where the magnetic field of the permanent magnet device is already small in magnitude, concentrating the magnetic field in a small cross-section of the yoke structure without exceeding the saturation magnetization of the yoke structure, thus substantially increasing the magnitude of the achievable magnetic field gradient, allowing for lower crosstalk, stronger coupling, and faster quantum gates.

[0074] According to another embodiment, the first end cap electrode and / or the second end cap electrode may be formed from a soft magnetic material. Exemplarily, the first end cap electrode and / or the second end cap electrode may be formed from the soft magnetic material.

[0075] In all cases, the soft magnetic material is surrounded by, for example, a permanent magnet arrangement configured to concentrate the magnetic field established by the permanent magnet arrangement specifically along a first axis in the region of the ion trap.

[0076] According to at least one embodiment of the quantum computing device, the first and second substrates have recesses extending vertically from an outer major surface of the first substrate to an outer major surface of the second substrate and laterally between the first RF electrode and the first DC electrode. Illustratively, the recesses extend completely vertically through the first and second substrates. Furthermore, the recesses extend laterally between the second RF electrode and the second DC electrode.

[0077] For example, the material of the intermediate layer, ie the material of the spacer layer or the material of the electrically insulating substrate, is completely penetrated by the recesses.

[0078] Illustratively, the ionic crystal, i.e., the trapped ion, is located within a recess, i.e., at least one side defining the recess laterally, in particular completely, surrounds the ionic crystal, i.e., the trapped ion. Illustratively, the first axis extends laterally within a main extension plane of the intermediate layer.

[0079] According to at least one embodiment of the quantum computing device, the at least one permanent magnet device is arranged above the first region and / or below the second region, with a main extension plane of the at least one permanent magnet device extending transversely, i.e. parallel to the further main extension plane of the ion trap.

[0080] In this case, the first axis is parallel to the axis of symmetry of the permanent magnet device, i.e., the first axis has a certain distance from the axis of symmetry. The magnitude of the magnetic field is maximized at positions on the axis of symmetry of the permanent magnet device. In this case, the magnetic field is illustratively a quadrupole magnetic field.

[0081] Illustratively, the permanent magnet device establishes a magnetic field that is primarily concentrated in a magnetic field plane extending primarily along the main extension plane. The magnitude of the magnetic field decays, for example, in the radial direction of an axis of symmetry perpendicular to the magnetic field plane. That is, the magnitude of the magnetic field is non-zero within a certain distance from the axis of symmetry, for example, along a first axis.

[0082] Illustratively, the magnetic field decays in the radial direction depending on at least one dimension of the permanent magnet device. The dimension may include at least one of the radius and / or thickness. For example, the decay length increases with the radius of the permanent magnet device, particularly the inner radius and / or the outer radius. Furthermore, the decay length increases with the thickness of the permanent magnet device perpendicular to the magnetic field plane.

[0083] For example, the magnetic field magnitude has a full width at half maximum (FWHM) of at least 1 μm or at least 10 μm and at most 10 mm or at most 500 μm in the radial direction of the axis of symmetry perpendicular to the magnetic field plane, so that even if the first axis has a distance to the axis of symmetry, the magnetic field magnitude still lies on the first axis.

[0084] Illustratively, the at least one permanent magnet arrangement has a vertical distance of at most 500 μm or at most 100 μm to the first region and / or the second region.

[0085] According to at least one embodiment of a quantum computing device, the ion trap includes a plurality of the sections, each configured to house one ionic crystal, the ionic crystals being arranged along a first axis.

[0086] According to at least one embodiment of the quantum computing device, the ionic crystals are configured to interact with each other by ionic transport and / or photonic links.

[0087] When the ionic crystals are configured to interact with each other by ion transport, the interaction, in particular the coupling of the different ionic crystals, is configured by a first separating cap electrode and a second separating cap electrode, as described herein above, disposed between two immediately adjacent sections.

[0088] When the ionic crystals are configured to interact with each other by a photonic link, the interaction, in particular the coupling of different ionic crystals, is constituted by a probabilistic photonic interface between the ionic crystals. Advantageously, a photonic link between at least two ionic crystals can be provided even over a relatively long distance between these ionic crystals.

[0089] According to at least one embodiment of the quantum computing device, the permanent magnet device includes a plurality of segments, i.e., at least four segments. For example, the permanent magnet device includes at least four segments, particularly at least eight segments, at least 16 segments, or at least 32 segments. Each segment includes a permanent magnet material. In particular, each of the segments includes the same permanent magnet material. Illustratively, the permanent magnet material includes a ferromagnetic material.

[0090] Each segment may, for example, be integrally formed. Alternatively, each segment may be formed from at least two sub-segments, the at least two sub-segments having the same material and / or magnetization properties.

[0091] In one preferred embodiment, the first axis extends linearly from one of the segments to another of the segments that is diametrically opposite said one of the segments relative to the center of the permanent magnet device, the two segments being displaced along the first axis.

[0092] According to at least one embodiment of the quantum computing device, each segment has a magnetization direction. The magnetization of each segment is defined by a vector field representing the dipole moment of the respective permanent magnetic material. That is, each permanent magnetic material exhibits a dipole moment. This means that when the permanent magnetic material is magnetized and in the absence of an external magnetic field, a magnetic field can be measured in the vicinity of the permanent magnetic material. The vector field, and in particular the dipole moment of the permanent magnetic material, defines the respective magnetization direction. The dipole moment points approximately in the magnetization direction.

[0093] According to at least one embodiment of the quantum computing device, the magnetization directions of the segments located in opposing regions are oriented in opposite directions, the segments being located in opposing regions relative to a center of the permanent magnet device, and the magnetization directions of the segments located in opposing regions are opposite to each other.

[0094] In particular, a first axis, in particular an axis of symmetry, is defined for two segments arranged opposite each other, the magnetization directions of each of the two segments being parallel to the first axis, in particular the axis of symmetry.

[0095] If there are m segments (m is an even natural number at least 4), the magnetization directions of two directly adjacent segments are rotated by 360°·3 / m with respect to each other.

[0096] Illustratively, the permanent magnet arrangement is a Halbach array.

[0097] In particular, the magnitude of the magnetic field in the central region established by the permanent magnet arrangement varies by at least 0.5 T / m and at most 500 T / m, in particular by at least 50 T / m and at most 250 T / m, illustratively by 150 T / m.

[0098] According to at least one embodiment, the quantum computing device further comprises at least one additional permanent magnet device. In particular, the quantum computing device can comprise multiple additional permanent magnet devices. The additional permanent magnet devices can have the same dimensions and / or characteristics as the permanent magnet devices described herein above.

[0099] According to at least one embodiment of the quantum computing device, the permanent magnet device has a rotated position relative to the additional permanent magnet device.

[0100] For example, the additional permanent magnet devices can be arranged in a rotated manner, in particular out-of-plane rotated manner, relative to the permanent magnet devices, such that an angle is enclosed by the respective main extension planes. This means that the additional main extension planes of the additional permanent magnet devices are rotated out of the plane of the main extension planes of the permanent magnet devices. Exemplarily, the angle can be between 0° and 90°.

[0101] For example, the additional permanent magnet device is rotated 90° relative to the permanent magnet device so that each of the main extension planes encloses an angle of 90°. In this embodiment, the first axis and the additional first axis corresponding to the additional permanent magnet device are positioned perpendicular to each other.

[0102] According to at least one embodiment of the quantum computing device, the permanent magnet device and the additional permanent magnet device are parallel to each other.

[0103] Illustratively, the first axis and the additional first axis are positioned parallel to each other.

[0104] Alternatively, the additional permanent magnet device is arranged in a rotated manner, in particular in-plane rotated manner, relative to the permanent magnet device. In this case, the main extension plane and the additional main extension plane are parallel to each other. For such an in-plane rotation, an angle is enclosed by the respective first axis, i.e., the first axis and the additional first axis. Exemplarily, the angle may be between 0° and 90°.

[0105] For example, the additional permanent magnet devices are rotated 90° in-plane relative to the permanent magnet devices so that their respective first axes subtend an angle of 90°. In this embodiment, the first axis and the additional first axis are positioned perpendicular to each other.

[0106] Each such device, including the permanent magnet device and the additional permanent magnet device, exemplarily forms a three-dimensional confined space, for example a three-dimensional gradient space, for the magnetic field.

[0107] Furthermore, quantum computers are designated herein as comprising the quantum computing devices described above, i.e., features relating to quantum computers are also applicable to quantum computing devices and vice versa.

[0108] The quantum computer is configured to perform quantum computing processes by using a quantum computing device, the trapped ions of which can be particularly well controlled and manipulated using the permanent magnet devices described herein above to perform a given quantum computation.

[0109] The quantum computing device is described in more detail below with reference to exemplary embodiments and associated figures. [Brief explanation of the drawings]

[0110] [Figure 1] 1 illustrates a quantum computing device in accordance with an example embodiment. [Figure 2] 1 illustrates a quantum computing device in accordance with an example embodiment. [Figure 3] 1 illustrates a quantum computing device in accordance with an example embodiment. [Figure 4] 1 illustrates a cross-sectional view of a quantum computing device in accordance with an example embodiment. [Figure 5] 1 illustrates a cross-sectional view of a quantum computing device in accordance with an example embodiment. [Figure 6] 1 illustrates a top view of an ion trap of a quantum computing device in accordance with an illustrative embodiment. [Figure 7] 1 illustrates a quantum computer in accordance with an example embodiment.

[0111] Elements that are identical, similar, or have the same effect are given the same reference numerals in the figures. The figures and the proportions of the elements shown therein are not to be considered true to scale. Rather, individual elements may be shown exaggeratedly large for better representation and / or better understandability. DETAILED DESCRIPTION OF THE INVENTION

[0112] The quantum computing device 1 according to the exemplary embodiment of FIG. 1 includes a permanent magnet device 2. The permanent magnet device 2 includes 16 segments 3. The segments 3 surround a space 5 of the quantum computing device 1, in which trapped ions 6 are trapped during operation of the quantum computing device 1. The segments 3 surround the space 5 in the shape of a ring. Each segment 3 is positioned such that its center is at a point on the ring.

[0113] The permanent magnet device 2 has a main extension plane extending along the x-axis and y-axis shown in FIG. 1. Each segment 3 has a cross-sectional shape of an annular sector or a circular ring-sector, and all segments share the same common inner ring and the same common outer ring. In particular, the width of each segment 3 tapers towards the space 5. This means that the opposite edges of each segment 3 facing the space 5 are curved. The normal bundle of the curved edges points away from the space 5. In other words, the radius of the curved edges is defined relative to the central region of the permanent magnet device 2.

[0114] The curved edges of the segments 3, which are arranged in opposing regions with respect to the central region and which face each other, have a minimum distance from each other of at least 0.001 cm and at most 100 cm. In particular, the minimum distance is at least 0.01 cm or at least 1 cm and at most 25 cm or at most 50 cm, for example, about 10 cm according to the exemplary embodiment of FIG. 1. The minimum distance divided by 2 is the inner radius R of the permanent magnet arrangement 2. i Define

[0115] Furthermore, each segment 3 has an extension along the corresponding minimum distance of at least 0.001 cm and at most 100 cm, in particular at least 0.01 cm or at least 1 cm and at most 25 cm or at most 50 cm, for example about 20 cm according to the exemplary embodiment of Fig. 1. The minimum distance divided by 2 and this extension along the corresponding minimum distance are taken to be the outer radius R of the permanent magnet arrangement 2. o Define

[0116] For example, directly adjacent segments 3 are spaced apart from one another: the mutually facing edges of directly adjacent segments 3 have a distance of about 1 mm from one another.

[0117] In this exemplary embodiment, each segment 3 has a line of symmetry that bisects the opposing edges facing the space 5. The line of symmetry is the same for segments 3 that are arranged opposite each other. One of the lines of symmetry represents a first axis 7 of the permanent magnet arrangement 2, which exemplarily extends in the main extension plane. In this embodiment, the first axis 7 is the axial symmetry axis 7' of the permanent magnet arrangement.

[0118] Furthermore, each segment 3 has a magnetization direction 4, which is shown as an arrow within the segment 3 in Figure 1. The magnetization directions 4 of the segments 3 located in opposite regions relative to the center of the permanent magnet device 2 are oriented in opposite directions. A first axis 7 of the permanent magnet device 2 is defined for the two segments 3 located opposite each other, and the magnetization directions 4 of each of the two segments 3 are parallel to the first axis 7.

[0119] Each magnetization direction 4 forms an angle with the first axis 7. These angles are all formed differently. For example, if the permanent magnet arrangement 2 comprises 16 segments 3, the angles of directly adjacent segments 3 differ from each other by 67.5°.

[0120] In the exemplary embodiment of Figures 1 and 2, the first axis 7 points in the direction of the x-axis.

[0121] Furthermore, the angle of the segment 3 that is parallel to the first axis 7 and has a magnetization direction 4 pointing in the same direction as the first axis 7 is 0°. The angle of the opposite segment 3 that is parallel to the first axis 7 and has a magnetization direction 4 pointing in the opposite direction to the first axis 7 is 180°.

[0122] When moving clockwise around the ring from a segment 3 having a magnetization direction 4 that is parallel to and points in the same direction as the first axis 7 back to this segment 3, the magnetization direction 4 also rotates clockwise.

[0123] Using such segments 3, the permanent magnet device 2 is configured to generate a quadrupole field, thus having different magnitudes at different positions along the first axis 7, i.e., magnetic field gradients along the first axis 7. Furthermore, during operation of the quantum computing device 1, the trapped ions 6 are positioned linearly one after the other along the first axis 7.

[0124] The quantum computing device 1 comprises an ion trap 100 for trapping trapped ions 6. The ion trap 100 has a further main plane of extension extending along the x-axis and the y-axis shown in Figure 1. That is to say, the main plane of extension of the permanent magnet device 2 and the further main plane of extension of the ion trap 100 are parallel to each other, in particular extend in the same plane.

[0125] It is conceivable that the further main plane of extension is rotated relative to the main plane of extension, i.e. the further main plane of extension can be oriented along any radial direction of the first axis 7 .

[0126] Ion trap 100 has a first region 14 and a second region 15 arranged one above the other, as shown, for example, in connection with FIGS. 3 and 4. For clarity, the reference numerals for ion trap 100 are shown in detail in connection with FIGS. 3 and 4. In this exemplary embodiment, first region 14 and second region 15 each extend parallel to the further main plane of extension. First region 14 comprises a first end cap electrode 41, a second end cap electrode 42, a first RF electrode 21, and a first DC electrode 31. Second region 15 further comprises a first end cap electrode 41, a second end cap electrode 42, a second RF electrode 22, and a second DC electrode 32. Exactly one of the first dc electrodes 31 , exactly one of the first rf electrodes 21 , exactly one of the second dc electrodes 32 , and exactly one of the second rf electrodes 22 form a section 47 .

[0127] A first endcap electrode 41 comprising two portions of the first region 14 is disposed at a first end region of the ion trap 100, and a second endcap electrode 42 comprising two portions of the first region 14 is disposed at a second end region of the ion trap 100, with sections 47 located therebetween. Additionally, a first endcap electrode 41 comprising two further portions of the second region 15 is disposed at the first end region of the ion trap 100, and a second endcap electrode 42 comprising two further portions of the second region 15 is disposed at a second end region of the ion trap 100, with sections 47 located therebetween.

[0128] The two portions of the first end cap electrode 41 in the first region 14 and the two further portions of the first end cap electrode 41 in the second region 15 completely overlap, in particular coincide, in top view. The two portions of the second end cap electrode 42 in the first region 14 and the two further portions of the second end cap electrode 42 in the second region 15 completely overlap, in particular coincide, in top view.

[0129] Sections 47 are disposed along first axis 7 between first end cap electrode 41 and second end cap electrode 42. Between immediately adjacent sections 47, first and second separated cap electrodes 45 and 46 are disposed in first and second regions 14 and 15, respectively.

[0130] The first separated cap electrode 45 comprises two parts, one part located in the first region 14 and the other part located in the second region 15. The two parts completely overlap in top view, in particular are congruent.

[0131] Furthermore, the second separating cap electrode 46 includes two parts, one part being arranged in the first region 14 and the other part being arranged in the second region 15. The two parts completely overlap, in particular coincide, in top view. The first separating cap electrode 45 and the second separating cap electrode 46 are arranged opposite each other with respect to the first axis 7.

[0132] It is further contemplated that the first isolated cap electrode 45 is configured to be supplied with an rf current and the second isolated cap electrode 46 is configured to be supplied with a dc current, in which case the first isolated cap electrode 45 and the second isolated cap electrode 46 of the first region 14 and the second region 15 are formed as a first rf electrode 21, a first dc electrode 31, a second rf electrode 22 and a second dc electrode 32, thereby forming one of the sections 47.

[0133] A first rf electrode 21 in one section 47 is arranged above a second dc electrode 32 in the same section 47. A first dc electrode 31 in the same section 47 is arranged above a second rf electrode 22 in the same section 47. Electrodes arranged one above the other completely overlap in top view, and are in particular congruent.

[0134] The two portions of the first end cap electrode 41 in the first region 14 are spaced apart by a first distance in a lateral direction perpendicular to the first axis 7. The first rf electrode 21 and the first dc electrode 31 in the section 47 are spaced apart by the first distance in a lateral direction perpendicular to the first axis 7. The first separated cap electrode 45 and the second separated cap electrode 46 are spaced apart by the first distance in a lateral direction perpendicular to the first axis 7.

[0135] Similarly, the electrodes in the second region 15 are spaced apart from one another by said first distance in a lateral direction perpendicular to the first axis 7 .

[0136] Furthermore, immediately adjacent electrodes have a second distance from each other in a lateral direction parallel to the first axis 7. The second distances may be equal to each other. Each second distance is smaller than said first distance.

[0137] The first and second end cap electrodes 41, 42 and the first and second separation cap electrodes 45, 46 are configured to trap target ions 6 along a first axis 7 via an applied dc current.

[0138] The first rf electrode 21, the first dc electrode 31, the second rf electrode 22, and the second dc electrode 32 are configured to trap target ions 6 in a radial direction relative to a first axis 7 via applied rf and dc currents.

[0139] Each section 47 is configured to trap exactly one ion crystal with an applied current, each ion crystal containing a plurality of trapped ions 6 arranged along a first axis 7.

[0140] The ion crystal, i.e., trapped ions 6, are disposed along a first axis 7, which is disposed vertically between the electrodes and laterally between the electrodes, i.e., vertically between the first region 14 and the second region 15, and laterally between the rf and dc electrodes of the first region 14 and the second region 15.

[0141] For example, the inner radius R according to the exemplary embodiment of FIG. i is approximately 100 μm, and the outer radius R o is about 300 μm. Illustratively, the inner radius R according to the exemplary embodiment of FIG. i is approximately 5 cm, and the outer radius R o is about 25cm.

[0142] Residual magnetic flux density B of each segment 3 R is, for example, 1 T. Thus, the magnetic field, and in particular the corresponding magnetic flux density B → (Vector is written this way for convenience) can be calculated by the following formula:

number

[0143] Furthermore, the distance d between directly adjacent trapped ions 6 is about 3 to 10 μm. → can be calculated for each position of the trapped ion 6. As a result, the difference for a particular transition between nearby trapped ions 6 can also be determined.

[0144] Exemplarily, σ between directly adjacent trapped ions 6 ± The frequency difference between the transitions is at least 10 kHz and at most 100 MHz. ± The transition can be excited by left- or right-handed circularly polarized electromagnetic waves with polarization perpendicular to the local magnetic field.

[0145] For example, the frequency difference of the π transitions between directly adjacent trapped ions 6 is at least 1 kHz and at most 10 MHz. Such π transitions are excited by linearly polarized electromagnetic waves with polarization parallel to the local magnetic field.

[0146] In contrast to the exemplary embodiment of FIG. 1, the quantum computing device 1 according to the exemplary embodiment of FIG. 2 comprises a permanent magnet arrangement 2 having segments 3 each having a square shape.

[0147] Each segment 3 has a square cross-sectional shape. The magnetization direction 4 relative to the sides of the square is the same for each segment 3. Directly adjacent segments 3 are rotated relative to each other so that the magnetization direction 4 of each segment 3 corresponds to the angle according to FIG.

[0148] 1 and 2, the permanent magnet device of the quantum computing device 1 according to the exemplary embodiment of FIG. 3 does not surround the ion trap 100. The quantum computing device 1 includes two permanent magnet devices, each of which surrounds an ion crystal. That is, each section 47 is provided with a permanent magnet device.

[0149] In this embodiment, the first axis 7 is the axis of symmetry 7' of each permanent magnet arrangement which extends along a common axis.

[0150] The magnetic field gradient generated by each permanent magnet device acts on the ion crystal in each section 47. Between the sections 47, i.e., in the region of the first separating cap electrode 45 and the second separating cap electrode 46, the magnetic field has a relatively low magnitude.

[0151] The permanent magnet device of the quantum computing device 1 according to the exemplary embodiment of FIG. 4 includes an intermediate region 16 disposed between a first region 14 and a second region 15. The first region 14 includes a first substrate 52 for the first DC electrode 31 and the first RF electrode 21, and for the first end cap electrode 41 and the second end cap electrode 42. The second region 14 includes a second substrate 53 for the second DC electrode 32 and the second RF electrode 22, and for the first end cap electrode 41 and the second end cap electrode 42. For example, the first RF electrode and the first DC electrode are provided on the inner major surface of the first substrate. Respective electrodes 41, 21, 32, 22, 31, and 42 are disposed on the outer and inner major surfaces of the respective substrates 52 and 53. The inner major surface of the first substrate 52 faces the inner major surface of the second substrate 53.

[0152] The intermediate region 16 is configured to separate the first substrate 52 and the second substrate 53 in the vertical direction. The intermediate region 16 illustratively includes a spacer layer 51.

[0153] The intermediate region 16 can include a permanent magnet arrangement according to FIG.

[0154] Alternatively, a soft magnetic material forming a yoke structure 60 is disposed between the first substrate 52 and the second substrate 53 in the intermediate region 16. In this case, the permanent magnet arrangement is formed as shown in one of Figures 1 or 2. The soft magnetic material is configured to enhance the difference in magnetic field magnitude in the region of the soft magnetic material, thus enhancing the magnetic field gradient along the first axis 7 for each section 47.

[0155] In contrast to the exemplary embodiment of Figure 4, the permanent magnet devices according to the exemplary embodiment of Figure 5 are positioned above the ion trap 100. The permanent magnet devices each have an axis of symmetry 7' that is spaced apart from the first axis 7 along which the trapped ions 6 are located.

[0156] The magnetic field magnitude of each permanent magnet arrangement is maximum on the axis of symmetry 7'. The magnetic field magnitude decays in the radial direction of the axis of symmetry 7', and the magnetic field magnitude is non-zero along the first axis 7. In particular, the maximum magnetic field magnitude along axis 7 is located directly below the permanent magnet arrangement 2 in a top view.

[0157] In this embodiment, it is contemplated that a soft magnetic material such as that described in connection with the exemplary embodiment of FIG. 4 is disposed within the intermediate region 16 .

[0158] The ion trap 100 of the quantum computing device 1 according to the exemplary embodiment of Figure 6 includes the intermediate region 16 according to the exemplary embodiment of Figures 4 and 5. The first substrate 52 and the second substrate 53 have recesses 54 extending completely through the first substrate 52 and the second substrate 53.

[0159] The first dc electrode 31 and the first rf electrode 21, and the first end cap electrode 41 and the second end cap electrode 42, are also disposed on the side of the first substrate 52 defined by the recess 54. In this context, the second dc electrode 32 and the second rf electrode 22, and the first end cap electrode 41 and the second end cap electrode 42 are also disposed on the side of the second substrate 53 defined by the recess 54. Thus, the electrodes 21, 22, 31, 32, 41, 42, 45, and 46 are disposed on the side of the first and second substrates that define the recess 54.

[0160] Intermediate region 16 may also have a recess 54 extending vertically from first region 14 to second region 15 and laterally between first rf electrode 21 and first dc electrode 31 and second rf electrode 22 and second dc electrode 32. During operation, ion crystals, and thus trapped ions 6, are located within recess 54 in intermediate region 16.

[0161] Quantum computer 8 according to the exemplary embodiment of Figure 7 comprises a quantum computing arrangement 1 according to one of the exemplary embodiments of Figures 1, 2, or 3 and a quantum computing device 9 located within chamber 10. Quantum computing device 9 is connected to components external to quantum computer 8 through chamber 10 by a number of connections 11. For example, connections 11 connect quantum computing device 9 with external electronics 12 and classical computer 13.

[0162] For example, quantum computing device 9 is ion trap 100 configured to trap, manipulate, and measure trapped ions, each of which represents a qubit, within space 5 during operation. To this end, quantum computing device 9 may include internal electronics, including electrodes, light guides, and / or electronic devices. The electronic devices may include circuits, integrated electronics, and / or detectors, such as photon detectors and / or charge detectors, and controllers. Illustratively, the internal electronics are provided for preprocessing. For example, these components allow measurement of the state of each of the qubits and allow gate operations on the qubits. Thus, quantum computing device 9 is configured to trap trapped ions and to perform operations and measurements on the trapped ions.

[0163] The quantum computing device 9 is mounted in a chamber 10, which may be an ultra-high vacuum chamber, an extremely high vacuum chamber, and / or a cryostat. If the chamber 10 is an ultra-high vacuum chamber or an extremely high vacuum chamber, the permanent magnet device 2 may be located outside the chamber 10. In this case, the permanent magnet device 2 surrounds the chamber 10. Alternatively, the permanent magnet device 2 may be located inside an ultra-high vacuum chamber or an extremely high vacuum chamber or a cryostat.

[0164] Illustratively, if the chamber 10 is a cryostat, the permanent magnet device 2 is disposed inside the chamber 10 (not shown here). It is also contemplated that if the chamber 10 is a cryostat, the permanent magnet device 2 may also be disposed outside the chamber 10 (not shown here).

[0165] Quantum computing device 9 is connected to external electronics 12 via connection 11. External electronics 12 can be located at least partially inside chamber 10 and partially outside chamber 10. Furthermore, external electronics 12 is connected to classical computer 13.

[0166] The external electronics 12 illustratively includes an analog-to-digital converter and a signal generator, such as a radio frequency generator, a microwave signal generator, a low frequency signal generator, and / or a DC signal generator. Additionally, the external electronics 12 may include transistor-transistor logic (TTL).

[0167] Additionally, the external electronics 12 may further comprise at least one laser system configured to cool the trapped ions 6. Furthermore, the laser system may be configured to excite specific states of the trapped ions 6.

[0168] Classical computer 13 is configured, for example, to provide and receive digital signals that correspond to control signals used for operations on qubits and measurement signals that correspond to the states of the qubits.

[0169] External electronics 12 is configured, among other things, to convert digital signals to analog signals and vice versa. Thus, external electronics 12 is configured to provide converted analog signals for manipulating qubits to quantum computing device 9. Furthermore, external electronics 12 is configured to provide measured analog signals from quantum computing device 9 to classical computer 13, or to process such signals to directly initiate any response signals generated by control electronics 12.

[0170] Classical computer 13 is illustratively configured to be provided with a particular algorithm, i.e., a predetermined quantum computation that solves a particular problem. Classical computer 13 is then configured to convert compiled code corresponding to the algorithm into commands for quantum computing device 9. The commands are then transferred to quantum computing device 9 via external electronics 12. Additionally, classical computer 13 is configured to receive measured results of the particular algorithm.

[0171] For example, all elements of the quantum computer 8, in particular all electronic elements of the quantum computer 8, are synchronized, for example by an atomic clock reference.

[0172] The present invention is not limited to the exemplary embodiments described therein, but rather includes any novel feature and any combination of features, and in particular any combination of features set forth in the claims, even if the feature or combination itself is not explicitly set forth in the claims or exemplary embodiments. [Explanation of symbols]

[0173] 1 Quantum computing device 2. Permanent magnet device 3 segments 4 Magnetization direction 6 Trapped ions 7 First Axis 7' Linear symmetry axis 8. Quantum Computers 9. Quantum Computing Devices 10 Chambers 11 Connection 12 External electronic equipment 13 Classical Computers 14 First Area 15 Second Area 16 Intermediate area 100 Ion Trap 21 first rf electrode 22 second rf electrode 31 First DC electrode 32 Second DC electrode 41 first end cap electrode 42 second end cap electrode 45 First Separation Cap Electrode 46 Second Separation Cap Electrode 47 Section 51 Spacer layer 52 First board 53 Second board 54 Recess 60 yoke structure d distance R i inner radius R o outer radius

Claims

1. A quantum computing device (1): a permanent magnet device (2) configured to establish magnetic fields having different magnitudes for different positions on a first axis (7); an ion trap (100) having a first region (14) and a second region (15) arranged one above the other; It has the ion trap (100) has at least one section (47) that is part of the first region (14) and the second region (15) for accommodating at least one ion crystal; the at least one ionic crystal includes a plurality of trapped ions (6) arranged along the first axis (7); Quantum computing device (1).

2. The first region (14) and the second region (15) each comprise at least two cap electrodes arranged in end regions of the first region (14) and the second region (15), respectively. Quantum computing device (1) according to claim 1.

3. The at least one section (47) comprises: a first radio frequency (rf) electrode (21) and a first direct current (dc) electrode (31) in the first region (14); a second rf electrode (22) and a second dc electrode (32) in the second region (15); Quantum computing device (1) according to claim 2, comprising:

4. the first rf electrode (21) and the first dc electrode (31) are spaced apart perpendicular to the first axis (7); the second rf electrode (22) and the second dc electrode (32) are spaced apart perpendicular to the first axis (7); The first rf electrode (21) is disposed above the second dc electrode (32); The first DC electrode (31) is disposed above the second RF electrode (22). Quantum computing device (1) according to claim 3.

5. 5. The quantum computing device (1) according to claim 3 or 4, wherein the first dc electrode (31), the second dc electrode (32), the first rf electrode (21), and the second rf electrode (22) are each formed as a metal film.

6. 6. The quantum computing device (1) of claim 5, wherein the metal film has a thickness of at most 30 μm.

7. an intermediate region (16) is disposed between the first region (14) and the second region (15); Quantum computing device (1) according to any one of claims 1 to 6.

8. the intermediate region (16) comprises an electrically insulating substrate (50) for the first dc electrode (31), the second dc electrode (32), the first rf electrode (21), and the second rf electrode (22); Quantum computing device (1) according to claim 7.

9. the first region (14) includes a first substrate (52); the second region (15) includes a second substrate (53); Quantum computing device (1) according to any one of claims 1 to 7.

10. said at least one permanent magnet device (2) is arranged in said intermediate region (16); and / or a soft magnetic material forming a yoke structure (60) is disposed within said intermediate region (16); or the at least one permanent magnet device (2) is arranged in the first region (14) and / or in the second region (15); and / or The soft magnetic material forming the yoke structure (60) is disposed in the first region (14) and / or the second region (15). Quantum computing device (1) according to any one of claims 7 to 9.

11. The first substrate (52) and the second substrate (53) have a recess (54) extending vertically from an outer major surface of the first substrate (52) to an outer major surface of the second substrate (53) and laterally between the first RF electrode (21) and the first DC electrode (31). Quantum computing device (1) according to any one of claims 9 to 10.

12. the at least one permanent magnet device (2) is arranged above the first region (14) and / or below the second region (15); Quantum computing device (1) according to any one of claims 1 to 11.

13. the ion trap (100) comprises a plurality of the sections (47); Each section (47) is configured to accommodate one ionic crystal; - the ionic crystal is arranged along the first axis (7); Quantum computing device (1) according to any one of claims 1 to 12.

14. the ionic crystals are configured to interact with each other by ionic transport and / or photonic links; Quantum computing device (1) according to claim 13.

15. The permanent magnet device (2) comprises a plurality of segments (3), i.e. at least four segments (3), Each segment (3) has a magnetization direction (4), Quantum computing device (1) according to any one of claims 1 to 14.

16. 16. The quantum computing device (1) of claim 15, wherein the magnetization directions of two of the segments arranged opposite each other are parallel to the first axis.

17. 17. The quantum computing device (1) according to claim 15 or 16, wherein the magnetization directions (4) of the segments (3) arranged in opposite regions are oriented in opposite directions.

18. 18. The quantum computing device (1) of any one of claims 1 to 17, wherein the permanent magnet arrangement (2) is a Halbach array.

19. and further comprising at least one additional permanent magnet device (2), the permanent magnet device (2) has a rotated position relative to the additional permanent magnet device (2), or the permanent magnet device (2) and the additional permanent magnet device (2) are parallel to each other; Quantum computing device (1) according to any one of claims 1 to 18.

20. 20. A quantum computer (8) comprising a quantum computing device (1) according to any one of claims 1 to 19, configured to perform quantum computing.

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