Quantum computing device and quantum computer

Abstract

It is proposed a quantum computing device (1) comprising:-a permanent magnet device (2) configured to establish magnetic fields having different intensities from one another for different positions on a first axis (7); and-an ion trap (100) having a first region (14) and a second region (15) arranged above each other, where-the ion trap (100) has at least one subarea (47) as part of the first region (14) and the second region (15) for accommodating at least one ionic crystal, and-the at least one ionic crystal comprises a plurality of trapped ions (6) arranged along a first axis (7). Furthermore, a quantum computer is proposed.

Description

[0001] The present disclosure relates to a quantum computing device and a quantum computer.

[0002] Exemplarily, an ion trap is configured to trap and manipulate ions for use in a quantum computing process, i.e., to perform computations. For charged trapped ions, interactions such as Coulomb repulsion create coupling of adjacent trapped ions and enable entanglement. Thus, to perform a quantum computing process using trapped ions, the trapped ions must be individually addressable and controllable with respect to each other.

[0003] Individual addressing of multiple trapped ions (e.g., a qubit register) is desirable with negligible crosstalk. However, crosstalk between adjacent trapped ions is typically a source of error that is difficult to control in a quantum computer process and may impede meaningful application of quantum error correction protocols and thus scalability.

[0004] Accordingly, the object to be solved is to provide a quantum computing device with improved controllability. Furthermore, a quantum computer including such a quantum computing device is provided.

[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, the quantum computing device includes a permanent magnet device configured to establish a magnetic field having different magnitudes for different positions along a first axis. Exemplarily, for different positions along the first axis, the magnitude of the magnetic field changes along the first axis.

[0007] The permanent magnet device has a main extension plane, wherein the first axis extends along the main extension plane. "Extending along the main extension plane" may herein and hereinafter mean that the first axis extends within the main extension plane or is parallel to the main extension plane.

[0008] The first axis is a virtual axis. For example, the first axis is the axis of symmetry of the permanent magnet device extending within the main extension plane. That is, in a cross-sectional view, the first axis divides the permanent magnet device into two halves along the main extension plane, and the shapes of the two halves are substantially the same. Exemplarily, "substantially the same" means that due to manufacturing tolerances of the permanent magnet device, the areas of the two halves, e.g., the cross-sectional areas of the two halves, may differ from each other by at most 5%, or at most 1%. Alternatively, the first axis has a distance from the axis of symmetry of the permanent magnet device.

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

[0010] For such a permanent magnet device, the intensity of the magnetic field changes continuously along the first axis, that is, for different positions on the first axis starting from the center. Therefore, the intensity of the magnetic field at different positions on the first axis is a characteristic of the magnetic field gradient along the first axis.

[0011] The magnetic field is represented by the magnetic flux density. In addition, the absolute value of the magnetic flux density corresponds to the intensity of the magnetic field at a predetermined position on the first axis.

[0012] The components of the magnetic field correspond to the components of a vector, where the vector can point in any direction relative to the first axis. That is, at least some of the vectors of the magnetic field at 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 the axial direction of the first axis.

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

[0014] The distribution of the intensity of the magnetic field is symmetric with respect to 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, that is, by a virtual line perpendicular to the first axis that bisects the first axis. The intensity of the magnetic field has a negative slope for one half and a positive slope for the other half. In terms of the magnetic field intensity along the first axis, the magnetic field gradient increases along the first axis, for example, approximately linearly. That is, the magnetic field gradient is approximately constant along the first axis starting from the center. Due to the production tolerances of the permanent magnet device, there may be a deviation of at most 5% from linearity, for example, in the central region.

[0015] According to at least one embodiment, the quantum computing device includes an ion trap having a first region and a second region arranged one above the other. Exemplarily, the first region extends along a first stage, and the second region extends along a second stage. For example, the ion trap has an additional main extension plane. The first stage and the second stage each extend parallel to the additional main extension plane.

[0016] The transverse direction is defined as parallel to the additional main extension plane, and the vertical direction is defined as perpendicular to the additional main extension plane. The first stage and the second stage are stacked one above the other in the vertical direction.

[0017] The first and second regions include components configured to trap ions at a predetermined well potential. The well potential can be static or dynamic. For example, the ions to be trapped are trapped by electromagnetic fields, in particular by radio frequency fields (for charged trapped ions).

[0018] According to at least one embodiment of the quantum computing device, the ion trap has at least one partition that is part of the first and second regions for accommodating at least one ion crystal. The at least one ion crystal includes a plurality of trapped ions arranged along a first axis. That is, the property of an ion crystal being a quantum register includes a plurality of trapped ions.

[0019] An ion crystal can include or comprise more than two, for example at least 8, at least 20, or at least 100 and / or at most 1000 trapped ions. Each trapped ion is a quantum bit, abbreviated as qubit.

[0020] If the ion trap has more than two partitions, the ion trap can accommodate more than two ion crystals. Each partition is configured to accommodate one of the ion crystals. The partitions do not overlap with each other in the lateral direction. All partitions are part of the first and second regions. That is to say, each partition is configured to divide the first and second regions.

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

[0022] Exemplarily, due to the application of a magnetic field to the two-level quantum system, the degeneracy of the second level is lifted, resulting in at least two (in particular at least three) sublevels. This leads to two, in particular three, possible transitions from each of the two, in particular three, sublevels to the first level.

[0023] If the trapped ion is an n-level quantum system, where n is a natural number equal to or greater than 2, then each n-level quantum system includes 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 can be achieved.

[0024] For trapped ions, the strength of the magnetic field is different for different positions on the first axis, and thus the splitting (depending on the local magnetic field strength) is also different for these trapped ions. Consequently, the frequency difference of specific transitions between adjacent trapped ions is also achieved. Due to the frequency difference, different resonance frequencies of adjacent trapped ions are also caused.

[0025] The total energy of each of the trapped ions is predetermined by the well potential and the energy characteristics of the corresponding transitions depending on the magnetic field strength.

[0026] One concept in particular uses a permanent magnet device in combination with an ion trap. Due to the different strengths of the magnetic field (i.e., the magnetic field gradient of the permanent magnet device), the trapped ions can thus be individually addressed in the frequency space, enabling an improved multi-qubit gate to be advantageously implemented and the coupling of adjacent trapped ions to be controlled. Additionally, by adjusting the coupling, highly entangled cluster states can be generated, which are advantageously used for quantum computing.

[0027] Advantageously, compared to an electromagnet, a permanent magnet exhibits relatively low noise and thus allows for high-fidelity control of the trapped ions.

[0028] In summary, a permanent magnet device is used to obtain a large magnetic field gradient experienced by the ions trapped in a planar or surface ion trap, to produce a highly different magnetic field seen by each ion storing a spin qubit. This is used for quantum information processing, which allows for advanced addressing in the frequency space and thus allows for individual single-qubit rotations with low crosstalk, and introduces an effective coupling between the ions, thus implementing a multi-qubit gate. This can also be used in combination with radio frequency (RF), for which, due to the long wavelength, addressing by focused radiation is not an option, but using an RF field for qubit control enables the application of established and economical miniaturization and integration techniques that are already common even in consumer electronic devices, and simplifies 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. In particular, a permanent magnet device in the form of a Halbach arrangement allows for a large magnetic field gradient even when the distance between any surface (including the main surfaces of the trap electrodes and the magnet) and the trapped ions should be large, which is desirable for high-fidelity gates of the trapped ions. This, in combination with the segmented ion trap described herein, allows for a flexible trapping configuration to trap several registers, for the splitting and merging of quantum registers, tuning the coupling constant between qubits, and generally expanding the capabilities of an ion trap-based quantum computer.

[0029] According to at least one embodiment of a quantum computing device, the first region and the second region each include at least two end cap electrodes, and the at least two end cap electrodes are 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 are located at opposite end faces of the ion trap.

[0030] For example, the first region has a first end cap electrode in the first end region and a second end cap electrode in the second end region, and at least one partition is located between the first end cap electrode and the second end cap electrode. In addition, the second region has 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 of the first region and the first end cap electrode of the second region overlap each other in the lateral direction, particularly identically. In this case, the first end cap electrode of the first region and the first end cap electrode of the second region have the same dimensions and are stacked on top of each other.

[0031] In addition, the second end cap electrode of the first region and the second end cap electrode of the second region overlap each other in the lateral direction, particularly identically. In this case, 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 on top of each other.

[0032] Exemplarily, the first end cap electrode of the first region and / or the first end cap electrode of the second region includes two parts. The two parts of the first region and / or the two parts of the second region are spaced apart from each other in the lateral direction, particularly perpendicular to the first axis. Similarly, the second end cap electrode of the first region and / or the second end cap electrode of the second region includes two other parts. The two other parts of the first region and / or the two other parts of the second region are spaced apart from each other in the lateral direction, particularly perpendicular to the first axis.

[0033] Each of the first end cap electrode and the second end cap electrode is configured to be supplied with direct current (abbreviated as dc). The first end cap electrode and the second end cap electrode are configured to trap ions to be trapped along the first axis.

[0034] For example, at least one partition is provided between the first end cap electrode and the second end cap electrode. If the ion trap includes more than one partition, additional cover electrodes are arranged between directly adjacent partitions in the first region and the second region, particularly including a first separation cover electrode and a second separation cover electrode in each of the first region and the second region. That is to say, the additional cover electrodes are configured to directly separate adjacent partitions from each other in the lateral direction, exemplarily in the axial direction. In addition, the additional cover electrodes are configured to trap ions to be trapped in each partition, particularly an ion crystal, along the first axis.

[0035] The dimensions and properties described hereinabove with respect to the first end-cap electrode and the second end-cap electrode are also applicable to a first separating cap electrode and a second separating cap electrode disposed respectively between directly adjacent partitions.

[0036] In particular, by directly separating adjacent partitions with the first separating cap electrode and the second separating cap electrode, coupling of directly adjacent ion crystals can be achieved by applying a predetermined dc current to the first separating cap electrode and the second separating cap electrode. That is, the potential barrier between directly adjacent ion crystals along the first axis can be pre-determined by the first separating cap electrode and the second separating cap electrode.

[0037] Advantageously, such coupling of adjacent ion crystals enables a computational process to be implemented as compared to a quantum computing device with uncoupled ion crystals.

[0038] According to at least one embodiment of the quantum computing device, at least one partition includes a first radio frequency (rf) electrode and a first direct current (dc) electrode located in a first region, and a second rf electrode and a second dc electrode located in a second region. The first rf electrode, the second rf electrode, the first dc electrode, and the second dc electrode each have a main extension plane parallel to an additional main extension plane 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 alternating current having a frequency range between 200 kHz and 30 GHz. For example, the direct current can be superimposed on the alternating current. The dc electrodes are each configured to be supplied with direct current. For example, the direct current can be superimposed on the alternating current.

[0040] The dc electrodes can also be replaced with rf electrodes. However, in each case, the rf electrodes and the dc electrodes in the first region and the second region of a partition are configured to trap the ions to be trapped 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 a 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 from each other perpendicular to the first axis, and the second rf electrode and the second dc electrode are spaced apart from each other perpendicular to the first axis. For example, 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, a first rf electrode is arranged above a second dc electrode, and a first dc electrode is arranged above a second rf electrode. For example, the first rf electrode and the second dc electrode overlap each other in the lateral direction, in particular, they overlap equally. For example, the first dc electrode and the second rf electrode overlap each other in the lateral direction, in particular, they overlap equally. Here and hereinafter, overlapping equally with each other in the lateral direction means that the corresponding electrodes overlap each other in the vertical direction in a top view.

[0044] For example, an ion crystal, that is, trapped ions, is located between a first region and a second region in the vertical direction, particularly between the first rf electrode and the first dc electrode, and between the second rf electrode and the second dc electrode. The ion crystal, that is, trapped ions, is located between the first rf electrode and the first dc electrode and between the second rf electrode and the second dc electrode in the lateral direction, that is, along a first axis.

[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. Exemplarily, the metal film includes gold.

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

[0047] According to at least one embodiment of the quantum computing device, an intermediate region is arranged between the first region and the second region. The intermediate region has a main extension plane extending in the lateral direction, that is, parallel to another main extension plane of the ion trap.

[0048] For example, the intermediate region is configured to be spaced apart from the first region and the second region in the vertical direction. For example, the intermediate region has a thickness of at least 1 μm and at most 500 μm in the vertical direction. For example, the intermediate region has a thickness of approximately 125 μm in the vertical direction.

[0049] According to at least one embodiment of the quantum computing arrangement, the intermediate region includes an electrically insulating substrate for the first dc electrode, the second dc electrode, the first rf electrode, and the second rf electrode. Exemplarily, the first rf electrode and the first dc electrode are provided on a first main surface of the electrically insulating substrate, and the second rf electrode and the second dc electrode are provided on a second main surface of the electrically insulating substrate opposite to the first main surface. Exemplarily, the first rf electrode, the first dc electrode, the second rf electrode, and the second dc electrode are applied by physical vapor deposition (e.g., sputtering), chemical vapor deposition, and / or electroplating processes.

[0050] The electrical insulating substrate is formed of or includes an electrical insulating material. For example, the electrical insulating material includes or comprises at least one of sapphire, aluminum oxide (such as Al 2 O 3 ), 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 may be formed of the same material as described above herein for the intermediate layer that is an electrical insulating substrate. Exemplarily, 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 may be formed of columns arranged in the edge regions of the first substrate and the second substrate.

[0052] Exemplarily, the first substrate is electrically insulating and provides a base for the first rf electrode and the first dc electrode. For example, the first rf electrode and the first dc electrode are disposed on the inner main surface of the first substrate. In addition, for example, the first rf electrode and the first dc electrode are disposed on the outer main surface of the first substrate.

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

[0054] For example, the second substrate is electrically insulating and provides a base for the second rf electrode and the second dc electrode. For example, the second rf electrode and the second dc electrode are disposed on the inner main surface of the second substrate. In addition, the second rf electrode and the second dc electrode are, for example, disposed on the outer main surface of the second substrate.

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

[0056] The inner main surface of the first substrate faces the inner main surface of the second substrate. The outer main surface of the first substrate faces away from the outer main surface of the second substrate.

[0057] The inner main surface and / or the outer main surface of the first substrate and / or the inner main surface and / or the outer main surface of the second substrate are largely covered by the corresponding electrodes. Here, largely means that the corresponding electrodes cover at least 40%, at least 60%, at least 80%, or at least 90% of the outer main surface of the first substrate and / or the outer main surface of the second substrate. Advantageously, in the case where the outer main surface is largely covered by the electrodes, charge accumulation can be particularly well avoided.

[0058] The first substrate and the second substrate are each formed of or include an electrically insulating material, and the electrically insulating material exemplarily includes or includes sapphire, aluminum oxide (such as Al 2 O 3 ), at least one of aluminum nitride, silicon or diamond or any other suitable material.

[0059] According to at least one embodiment of the quantum computing device, at least one permanent magnet arrangement is arranged in the intermediate region. In this case, a main extension plane of the at least one permanent magnet arrangement extends in a lateral direction, ie parallel to a further main extension plane of the ion trap.

[0060] If the intermediate region comprises an electrically insulating substrate, the at least one permanent magnet arrangement may be embedded in the electrically insulating substrate. Here, "embedded" means that at least one outer surface of the at least one permanent magnet arrangement is covered by the electrically insulating substrate. For example, all outer surfaces of the at least one permanent magnet arrangement are covered by the electrically insulating substrate.

[0061] If the quantum computing device comprises more than one permanent magnet device, all permanent magnet devices may be arranged in the middle region. For example, the permanent magnet devices are spaced apart from each other in a lateral direction along the first axis. If the quantum computing device comprises more than one partition, at least one of the partitions, in particular each partition or a group of more than one partition is associated with one of the permanent magnet devices.

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

[0063] In this case, the first axis is an axis of symmetry of the permanent magnet arrangement and the trapped ions are located on the axis of symmetry of the permanent magnet arrangement. In this case, the permanent magnet arrangement is part of an ion trap.

[0064] If the quantum computing device comprises more than one permanent magnet device, the permanent magnet devices can be configured to provide different magnetic field gradients. Thus, regions with relatively high magnetic field strength and regions with relatively low magnetic field strength can be achieved. Advantageously, due to such different regions, in particular due to the regions with relatively low magnetic field strength, non-critical ion transport can be achieved.

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

[0066] If the intermediate region includes an electrically insulating substrate, the soft magnetic material can be embedded in the electrically insulating substrate. Here, "embedded" means that at least one outer surface of the soft magnetic material is covered by the electrically insulating substrate. Exemplarily, 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 arranged within the intermediate region. In this case, the soft magnetic material and the permanent magnet device are part of the ion trap.

[0068] Alternatively, only the soft magnetic material is arranged within the intermediate region, while the permanent magnet device surrounds the ion trap. In this case, only the soft magnetic material is part of the ion trap.

[0069] Alternatively or additionally, it is conceivable that the soft magnetic material is not part of the ion trap. In this case, the soft magnetic material is arranged externally with respect to the ion trap.

[0070] Alternatively or additionally, at least one permanent magnet device is arranged on the main surface of the electrically insulating substrate, and / or the soft magnetic material is arranged on the main surface of the electrically insulating substrate.

[0071] According to at least one embodiment of the quantum computing device, at least one permanent magnet device is arranged within the first region and / or the second region. Exemplarily, at least one permanent magnet device is embedded in the first substrate and / or the second substrate. Additionally or alternatively, at least one permanent magnet device is arranged on the inner main surface and / or the outer main surface of the first substrate, and / or at least one permanent magnet device is arranged on the inner main surface and / or the outer main 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 arranged within the first region and / or the second region. Exemplarily, the soft magnetic material is embedded in the first substrate and / or the second substrate. Additionally or alternatively, the soft magnetic material is arranged on the inner main surface and / or the outer main surface of the first substrate, and / or the soft magnetic material is arranged on the inner main surface and / or the outer main surface of the second substrate.

[0073] In summary, the yoke structure is placed in a region where the intensity of the magnetic field of the permanent magnet device is already small, and it is concentrated into a small cross-section of the yoke structure without exceeding the saturation magnetization of the yoke structure, thus greatly increasing the intensity 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 can be formed of a soft magnetic material. Exemplarily, the first cap electrode and / or the second cap electrode can be formed of a soft magnetic material.

[0075] For example, in all cases, the soft magnetic material is surrounded by a permanent magnet device which is configured to concentrate the magnetic field established by the permanent magnet device particularly within the region of the ion trap along a first axis.

[0076] According to at least one embodiment of the quantum computing device, the first substrate and the second substrate have a recess that extends in a vertical direction from the outer main surface of the first substrate to the outer main surface of the second substrate and extends in a lateral direction between the first rf electrode and the first dc electrode. Exemplarily, the recess completely penetrates the first substrate and the second substrate in the vertical direction. Further, the recess extends in the lateral direction between the second rf electrode and the second dc electrode.

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

[0078] Exemplarily, the ion crystal, i.e., the trapped ion, is located within the recess. That is, at least one side surface defining the recess particularly completely surrounds the ion crystal, i.e., the trapped ion, in the lateral direction. Exemplarily, the first axis extends in the lateral direction within the main extension plane of the intermediate layer.

[0079] According to at least one embodiment of the quantum computing device, at least one permanent magnet device is arranged above the first region and / or below the second region. In this case, the main extension plane of the at least one permanent magnet device extends in the lateral direction, 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 distance from the axis of symmetry. The intensity of the magnetic field has a maximum value at the position on the axis of symmetry of the permanent magnet device. In this case, the magnetic field is exemplarily a magnetic quadrupole field.

[0081] Exemplarily, the permanent magnet device establishes a magnetic field that is mainly concentrated in the magnetic field plane and mainly extends along the main extension plane. The intensity of the magnetic field decays, for example, perpendicular to the magnetic field plane in the radial direction of the axis of symmetry. That is, within the distance of the axis of symmetry, for example, along the first axis, the intensity of the magnetic field is not zero.

[0082] For example, the decay of the magnetic field in the radial direction depends on at least one dimension of the permanent magnet device. This dimension may include at least one of a radius and / or a thickness. For example, the decay length increases with the radius (particularly the inner radius and / or the outer radius of the permanent magnet device). Further, the decay length increases with the thickness of the permanent magnet device perpendicular to the magnetic field plane.

[0083] For example, the magnetic field 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 a radial direction perpendicular to the axis of symmetry of the plane of the magnetic field. Thus, even if the first axis has a distance from the axis of symmetry, the magnetic field strength still exists on the first axis.

[0084] For example, at least one permanent magnet device has a distance of at most 500 μm or at most 100 μm to the first region and / or the second region in the vertical direction.

[0085] According to at least one embodiment of the quantum computing device, the ion trap includes a plurality of partitions, and each partition is configured to accommodate an ion crystal. The ion crystals are arranged along a first axis.

[0086] According to at least one embodiment of the quantum computing device, the ion crystals are configured to interact via ion transport and / or photon links.

[0087] As described hereinabove, if the ion crystals are configured to interact via ion transport, the interaction, in particular the coupling between different ion crystals, is configured by a first separation cover electrode and a second separation cover electrode arranged between two directly adjacent partitions.

[0088] If the ion crystals are configured to interact via photon links, the interaction, in particular the coupling between different ion crystals, is configured by a probabilistic photon interface between the ion crystals. Advantageously, a photon link between at least two ion crystals can also be provided for a relatively long distance between these ion crystals.

[0089] According to at least one embodiment of the quantum computing device, the permanent magnet device includes a plurality of segments, namely at least four segments. For example, the permanent magnet device includes at least four segments, in particular at least 8 segments, at least 16 segments or at least 32 segments. Each segment includes a permanent magnetic material. In particular, each of the segments includes the same permanent magnetic material. Exemplarily, the permanent magnetic material includes a ferromagnetic material.

[0090] Each segment is formed integrally, for example. Alternatively, each segment is formed by at least two sub-segments, where the at least two sub-segments have the same material and / or magnetization properties.

[0091] In a preferred embodiment, the first axis extends linearly from one segment to another segment of the segments, and the other segment is directly opposite to the one segment with respect to the center of the permanent magnet device. These two segments are shifted 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 magnetic segment is defined by a vector field representing the dipole moment of the corresponding permanent magnetic material. That is, the corresponding permanent magnetic material exhibits a dipole moment. This means that the permanent magnetic material is magnetized such that in the absence of an external magnetic field, a magnetic field can be measured near the permanent magnetic material. The vector field, in particular the dipole moment of the permanent magnetic material, defines the corresponding magnetization direction. The dipole moment mainly points in the magnetization direction.

[0093] According to at least one embodiment of the quantum computing device, the magnetization directions of the segments arranged in opposite regions point in opposite directions. The segments are arranged in opposite regions relative to the center of the permanent magnet device. The magnetization directions of the segments arranged in opposite regions are diametrically opposite to each other.

[0094] In particular, two segments arranged opposite to each other define a first axis, in particular an axis of rotational symmetry, wherein the magnetization directions of the corresponding two segments are parallel to the first axis, in particular the axis of rotational symmetry.

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

[0096] Exemplarily, the permanent magnet device is a Halbach device.

[0097] In particular, the intensity of the magnetic field in the central region established by the permanent magnet device changes by at least 0.5 T / m and at most 500 T / m. In particular, the intensity of the magnetic field in the central region changes by at least 50 T / m and at most 250 T / m, and is exemplarily 150 T / m.

[0098] According to at least one embodiment, the quantum computing device further includes at least one additional permanent magnet device. In particular, the quantum computing device may include a number of additional permanent magnet devices. The additional permanent magnet device may have the same size and / or properties as the permanent magnet device described above in this text.

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

[0100] For example, the additional permanent magnet device is arranged relative to the permanent magnet device in a rotational form, in particular an out-of-plane rotational form, such that the corresponding main extension planes form an angle. That is, the additional main extension plane of the additional permanent magnet device is rotated out of the main extension plane of the permanent magnet device. Exemplarily, the angle may be between 0° and 90°.

[0101] For example, the additional permanent magnet device is rotated 90° relative to the permanent magnet device such that the corresponding main extension planes form 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] Exemplarily, 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 rotational form, in particular in a in-plane rotational form, 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 formed by the corresponding first axes (i.e., the first axis and the additional first axis). Exemplarily, this angle can be between 0° and 90°.

[0105] For example, the additional permanent magnet device is rotated 90° in the plane relative to the permanent magnet device such that the corresponding first axes form an angle of 90°. In this embodiment, the first axis and the additional first axis are positioned perpendicular to each other.

[0106] Such an arrangement includes a permanent magnet device and an additional permanent magnet device, and each permanent magnet device exemplarily forms a three-dimensionally confined space in terms of the magnetic field, such as a three-dimensional gradient space.

[0107] Furthermore, a quantum computer is specified, wherein the quantum computer includes a quantum computing device as described hereinabove. That is to say, the features regarding the quantum computer also apply to the quantum computing device and vice versa.

[0108] The quantum computer is configured to perform a quantum computing process by using the quantum computing device. The trapped ions of the quantum computing device can be particularly well controlled and manipulated by using the permanent magnet device described hereinabove to perform a predetermined quantum computing.

[0109] Hereinafter, the quantum computing device will be described in more detail with reference to exemplary embodiments and the associated drawings.

[0110] Figure 1 and Figure 2 Each shows a quantum computing device according to an exemplary embodiment.

[0111] Figure 3 Shows a quantum computing device according to an exemplary embodiment.

[0112] Figure 4 and Figure 5 Each shows a cross-sectional view of a quantum computing device according to an exemplary embodiment.

[0113] Figure 6 A top view of an ion trap of a quantum computing device according to an exemplary embodiment is shown.

[0114] Figure 7 A quantum computer according to an exemplary embodiment is shown.

[0115] Identical, similar or elements having the same effect are given the same reference numerals in the drawings. The proportions of the figures and elements shown in the drawings should not be regarded as true proportions. Instead, individual elements may be exaggerated for better representation and / or better understanding.

[0116] According to Figure 1 an exemplary embodiment of, a quantum computing device 1 includes a permanent magnet device 2. The permanent magnet arrangement 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 form of a ring. Each segment 3 is arranged such that its center is at a point on the ring.

[0117] The permanent magnet device 2 has a main extension plane extending along the Figure 1 x-axis and y-axis shown in. Each segment 3 has a cross-sectional form of an annular sector or a toroidal sector, where 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. That is, 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. That is, a radius defining the curved edges is defined with respect to the central region of the permanent magnet device 2.

[0118] The curved edges of the segments 3 arranged in opposite regions with respect to the central region and facing each other have a minimum distance of at least 0.001 cm and at most 100 cm from each other. 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 according to Figure 1 an exemplary embodiment of, about 10 cm. Half of the minimum distance defines the inner radius R i of the permanent magnet device 2.

[0119] Furthermore, the range of each segment 3 along the corresponding minimum distance is at least 0.001 cm and at most 100 cm, especially at least 0.01 cm or at least 1 cm and at most 25 cm or at most 50 cm, for example according to Figure 1 an exemplary embodiment of, about 20 cm. Half of the minimum distance and the range along the corresponding minimum distance define the outer radius R o of the permanent magnet device 2.

[0120] For example, the directly adjacent segments 3 are spaced apart from each other. The edges of the directly adjacent segments 3 facing each other have a distance of approximately 1 mm to each other.

[0121] In this exemplary embodiment, each segment 3 has a symmetry line that bisects the opposite edges facing the space 5. The symmetry lines are the same for segments 3 arranged opposite to each other. One of the symmetry lines represents the first axis 7 of the permanent magnet device 2, where the first axis 7 extends, for example, in the main extension plane. In this exemplary embodiment, the first axis 7 is the axis of symmetry 7' of the permanent magnet device.

[0122] In addition, each segment 3 has a magnetization direction 4, which is depicted as Figure 1 an arrow within the segment 3 in

[0123] The magnetization directions 4 of segments 3 arranged in opposite regions relative to the center of the permanent magnet device 2 point in opposite directions. The first axis 7 of the permanent magnet device 2 is defined with respect to two segments 3 arranged opposite to each other, where the magnetization directions 4 of the corresponding two segments 3 are parallel to the first axis 7.

[0124] In Figure 1 and Figure 2 the exemplary embodiment, the first axis 7 points in the direction of the x-axis.

[0125] In addition, the angle of the segment 3 having a magnetization direction 4 parallel to the first axis 7 and pointing in the same direction as the first axis 7 is 0°. The angle of the opposite segment 3 having a magnetization direction 4 parallel to the first axis 7 and pointing in the opposite direction to the first axis 7 is 180°.

[0126] Starting from the segment 3 having a magnetization direction 4 parallel to the first axis 7 and pointing in the same direction as the first axis 7 and going clockwise around the ring back to this segment 3, the magnetization direction 4 also rotates clockwise.

[0127] In the case of such segments 3, the permanent magnet device 2 is configured to generate a quadrupole magnetic field and thus has different intensities at different positions along the first axis 7, that is, there is a magnetic field gradient along the first axis 7. In addition, during the operation of the quantum computing device 1, the trapped ions 6 are arranged linearly adjacent to each other along the first axis 7.

[0128] The quantum computing device 1 includes an ion trap 100 for trapping the trapped ions 6. The ion trap 100 has along Figure 1A further main extension plane extending along the x-axis and y-axis as shown. That is, the main extension plane of the permanent magnet device 2 and this further main extension plane of the ion trap 100 are parallel to each other, and in particular, extend in the same plane.

[0129] It is conceivable that this further main extension plane is rotated relative to the main extension plane, that is, this further main extension plane can be oriented in each radial direction along the first axis 7.

[0130] For example, in combination with Figure 3 and Figure 4 as shown, the ion trap 100 has a first region 14 and a second region 15 arranged one above the other. For better representation, in combination with Figure 3 and Figure 4 the reference numerals regarding the ion trap 100 are shown in detail. In this exemplary embodiment, the first region 14 and the second region 15 each extend parallel to this further main extension plane. The first region 14 includes a first end cap electrode 41, a second end cap electrode 42, a first rf electrode 21, and a first dc electrode 31. In addition, the second region 15 includes 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 partition 47.

[0131] The two-part first end cap electrode 41 of the first region 14 is arranged in the first end region of the ion trap 100, and the two-part second end cap electrode 42 of the first region 14 is arranged in the second end region of the ion trap 100, with the partition 47 therebetween. In addition, the first end cap electrode 41 (including two additional parts) of the second region 15 is arranged in the first end region of the ion trap 100, and the second end cap electrode 42 (including two additional parts) of the second region 15 is arranged in the second end region of the ion trap 100, with the partition 47 therebetween.

[0132] The two parts of the first end cap electrode 41 of the first region 14 and the two additional parts of the first end cap electrode 41 in the second region 15 completely overlap in a top view, and in particular, overlap congruently. The two parts of the second end cap electrode 42 of the first region 14 and the two additional parts of the second end cap electrode 42 in the second region 15 completely overlap in a top view, and in particular, overlap congruently.

[0133] The partition 47 is arranged along the first axis 7 between the first end cap electrode 41 and the second end cap electrode 42. Between directly adjacent partitions 47, a first separation cap electrode 45 and a second separation cap electrode 46 are arranged in each of the first region 14 and the second region 15.

[0134] The first separation cover electrode 45 includes two parts, wherein, one part is arranged in the first region 14, and the other part is arranged in the second region 15. In a top view, the two parts completely overlap, especially identically overlap.

[0135] In addition, the second separation cover electrode 46 includes two parts, wherein, one part is arranged in the first region 14, and the other part is arranged in the second region 15. In a top view, the two parts completely overlap, especially identically overlap. The first separation cover electrode 45 and the second separation cover electrode 46 are arranged opposite to each other with respect to the first axis 7.

[0136] It is also conceivable that the first separation cover electrode 45 is configured to be supplied with rf current, and the second separation cover electrode 46 is configured to be supplied with dc current. In this case, the first separation cover electrode 45 and the second separation cover electrode 46 of the first region 14 and the second region 15 are formed as the first rf electrode 21, the first dc electrode 31, the second rf electrode 22, and the second dc electrode 32, and thus form one of the partitions 47.

[0137] The first rf electrode 21 of a partition 47 is arranged above the second dc electrode 32 of the same partition 47. The first dc electrode 31 of the same partition 47 is arranged above the second rf electrode 22 of the same partition 47. In a top view, the electrodes arranged above each other completely overlap, especially identically overlap.

[0138] The two parts of the first end cover electrode 41 of the first region 14 are spaced apart from each other 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 of the partition 47 are spaced apart from each other by a first distance in a lateral direction perpendicular to the first axis 7. The first separation cover electrode 45 and the second separation cover electrode 46 are spaced apart from each other by a first distance in a lateral direction perpendicular to the first axis 7.

[0139] Similarly, the electrodes of the second region 15 are spaced apart from each other by a first distance in a lateral direction perpendicular to the first axis 7.

[0140] In addition, directly adjacent electrodes have a second distance to each other in a lateral direction parallel to the first axis 7. The second distances can be equal to each other. Each second distance is less than the first distance.

[0141] The first end cover electrode 41 and the second end cover electrode 42, and the first separation cover electrode 45 and the second separation cover electrode 46 are configured to capture the ions 6 to be captured along the first axis 7 via an applied dc current.

[0142] The first RF electrode 21, the first DC electrode 31, the second RF electrode 22, and the second DC electrode 32 are configured to capture the ions 6 to be captured in the radial direction with respect to the first axis 7 via the applied RF current and DC current.

[0143] Each partition 47 is configured to capture exactly one ion crystal using the applied current. Each ion crystal includes a plurality of captured ions 6 arranged along the first axis 7.

[0144] The ion crystal, i.e., the captured ions 6, is arranged along the first axis 7, where the first axis 7 is arranged between the electrodes in the vertical direction and between the electrodes in the lateral direction. That is, in the vertical direction between the first region 14 and the second region 15 and in the lateral direction between the RF electrodes and the DC electrodes in the first region 14 and the second region 15, the ion crystal, i.e., the captured ions 6, is provided.

[0145] For example, according to Figure 3 the exemplary embodiment of, the inner radius R i is about 100 μm, and the outer radius R o is about 300 μm. Exemplarily, according to Figure 2 the exemplary embodiment of, the inner radius R i is about 5 cm, and the outer radius R o is about 25 cm.

[0146] The remanent magnetic field B of each of the segments 3 R is, for example, 1 T. Therefore, the magnetic field, particularly the corresponding magnetic flux density can be calculated by the following formula:

[0147]

[0148] The origin of the coordinates x and y is located at the center of the permanent magnet device 2.

[0149] Furthermore, the distance d between directly adjacent captured ions 6 is about 3 μm to 10 μm. Therefore, the magnetic flux density can be calculated for each position of the captured ions 6 Therefore, the difference in the specific transitions between adjacent captured ions 6 can also be determined.

[0150] Exemplarily, the frequency difference of the σ ± -transition between directly adjacent captured ions 6 is at least 10 kHz and at most 100 MHz. The σ ± -transition can be excited by left or right circularly polarized electromagnetic waves with polarization perpendicular to the local magnetic field.

[0151] For example, the frequency difference of 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.

[0152] Compared with Figure 1 the exemplary embodiment of Figure 2 the quantum computing device 1 according to the exemplary embodiment of

[0153] each section 3 has a square cross-sectional form. For each section 3, the magnetization direction 4 with respect to the edges of the square is the same. The directly adjacent sections 3 are rotated relative to each other such that the magnetization direction 4 of each section 3 corresponds to an angle according to Figure 1 the exemplary embodiment of

[0154] Compared with Figure 1 and Figure 2 the exemplary embodiment of Figure 3 in the exemplary embodiment of, the permanent magnet device of the quantum computing device 1 does not surround the ion trap 100. The quantum computing device 1 includes two permanent magnet devices, wherein each of the permanent magnet devices surrounds the ion crystal. That is, each partition 47 is provided with a permanent magnet device.

[0155] In this embodiment, the first axis 7 is the axis of symmetry 7' of each permanent magnet device extending along a common axis.

[0156] The magnetic field gradient generated by each permanent magnet device acts on the ion crystals in each of the partitions 47. Between the partitions 47, that is, in the region of the first separation cover electrode 45 and the second separation cover electrode 46, the intensity of the magnetic field is relatively small.

[0157] According to Figure 4 the exemplary embodiment of, the permanent magnet device of the quantum computing device 1 has an intermediate region 16 arranged between the first region 14 and the 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 arranged on the inner main surface of the first substrate. The corresponding electrodes 41, 21, 32, 22, 31, 42 are arranged on the outer main surface and the inner main surface of the corresponding substrates 52, 53. The inner main surface of the first substrate 52 faces the inner main surface of the second substrate 53.

[0158] The intermediate region 16 is configured to space the first substrate 52 and the second substrate 53 apart in the vertical direction. The intermediate region 16 exemplarily includes a spacer layer 51.

[0159] The intermediate region 16 may include a permanent magnetic device according to Figure 3 .

[0160] Alternatively, within the intermediate region 16, a soft magnetic material forming a yoke structure 60 is arranged between the first substrate 52 and the second substrate 53. In this case, as shown in one of Figure 1 and Figure 2 , a permanent magnetic device is formed. The soft magnetic material is configured to enhance the difference in the intensity of the magnetic field in the region of the soft magnetic material, and thus, enhance the magnetic field gradient of each partition 47 along the first axis 7.

[0161] Compared with the exemplary embodiment of Figure 4 , the permanent magnetic devices according to the exemplary embodiment of Figure 5 are arranged above the ion trap 100. Each permanent magnetic device has an axis of symmetry 7' spaced apart from the first axis 7 where the ion trap 6 is located.

[0162] The intensity of the magnetic field of each permanent magnetic arrangement has a maximum value on the axis of symmetry 7'. The intensity of the magnetic field decays in the radial direction of the axis of symmetry 7' such that the intensity of the magnetic field is non-zero along the first axis 7. In particular, in a top view, the maximum magnetic field intensity along the axis 7 is located directly below the permanent magnetic device 2.

[0163] In this embodiment, it is conceivable that a soft magnetic material as described in connection with the exemplary embodiment of Figure 4 is arranged within the intermediate region 16.

[0164] According to the exemplary embodiment of Figure 6 , the ion trap 100 of the quantum computing device 1 includes an intermediate region 16 according to the exemplary embodiments of Figure 4 and Figure 5 . The first substrate 52 and the second substrate 53 have recesses 54 that completely penetrate the first substrate 52 and the second substrate 53.

[0165] The first dc electrode 31, the first rf electrode 21, and the first end cap electrode 41 and the second end cap electrode 42 are also arranged on the side surface of the first substrate 52 defined by the recess 54. In this context, the second dc electrode 32, the second rf electrode 22, and the first end cap electrode 41 and the second end cap electrode 42 are also arranged on the side surface of the second substrate 53 defined by the recess 54. Accordingly, the electrodes 21, 22, 31, 32, 41, 42, 45, 46 are arranged on the side surfaces of the first substrate and the second substrate that define the recess 54.

[0166] The intermediate region 16 may also have a recess 54 that extends in the vertical direction from the first region 14 to the second region 15 and in the lateral direction between the first rf electrode 21 and the first dc electrode 31 and between the second rf electrode 22 and the second dc electrode 32. In operation, the ion crystal, i.e., the trapped ions 6, is located in the recess 54 within the intermediate region 16.

[0167] According to Figure 7 An example embodiment of the quantum computer 8 includes a quantum computing device 1 according to Figure 1 , Figure 2 or Figure 3 and a quantum computing device 9 located within the chamber 10. The quantum computing device 9 is connected via a plurality of connections 11 to external components of the quantum computer 8 via the chamber 10. For example, the connections 11 connect the quantum computing device 9 to an external electronic device 12 and a classical computer 13.

[0168] For example, the quantum computing device 9 is an ion trap 100 configured to trap, manipulate, and measure trapped ions within the space 5 during operation, each ion being a qubit. To this end, the quantum computing device 9 may include electrodes, optical waveguides, and / or internal electronics including electronic devices. The electronic devices may include circuits, integrated electronic components, and / or detectors (such as photon detectors and / or charge detectors), controllers. Exemplarily, internal electronics are provided for preprocessing. For example, these components allow the corresponding state of the qubit to be measured and allow gate operations to be performed on the qubit. Thus, the quantum computing device 9 is configured to trap the trapped ions and operate on and measure the trapped ions.

[0169] The quantum computing device 9 is installed in the chamber 10, where the chamber 10 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 arranged outside the chamber 10. In this case, the permanent magnet device 2 surrounds the chamber 10. Alternatively, the permanent magnet device 2 may also be arranged inside the ultra-high vacuum chamber or the extremely high vacuum chamber or the cryostat.

[0170] Exemplarily, if the chamber 10 is a cryostat, the permanent magnet device 2 is arranged inside the chamber 10 (not shown here). It is also conceivable that if the chamber 10 is a cryostat, the permanent magnet device 2 may also be arranged outside the chamber 10 (not shown here).

[0171] The quantum computing device 9 is connected to the external electronic device 12 via the connection 11. The external electronic device 12 may be at least partially located inside the chamber 10 and partially located outside the chamber 10. In addition, the external electronic device 12 is connected to the classical computer 13.

[0172] The external electronic device 12 exemplarily 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 direct current signal generator. In addition, the external electronic device 12 may include transistor-transistor logic TTL.

[0173] In addition, the external electronic device 12 may further include at least one laser system configured to cool the ions 6 to be trapped. In addition, the laser system may be configured to excite a specific state of the trapped ions 6.

[0174] For example, the classical computer 13 is configured to provide and receive digital signals. The digital signals correspond to control signals for operations performed on the qubits and measurement signals corresponding to the states of the qubits.

[0175] The external electronic device 12 is particularly configured to convert digital signals into analog signals and vice versa. Thus, the external electronic device 12 is configured to provide the converted analog signals for manipulating the qubits to the quantum computing device 9. In addition, the external electronic device 12 is configured to provide the measured analog signals from the quantum computing device 9 to the classical computer 13 or process such signals to directly initiate some response signals generated by the control electronic device 12.

[0176] The classical computer 13 is exemplarily configured to be provided with a specific algorithm, i.e., a predetermined quantum computation for solving a specific problem. Then, the classical computer 13 is configured to convert the compiled code corresponding to the algorithm into commands for the quantum computing device 9. These commands are then forwarded to the quantum computing device 9 via the external electronic device 12. In addition, the classical computer 13 is configured to receive the measurement results of a specific algorithm.

[0177] For example, all elements of the quantum computer 8, particularly all electronic elements of the quantum computer 8, are synchronized by, for example, an atomic clock reference.

[0178] The present invention is not limited to the exemplary embodiments described thereby. On the contrary, the present invention includes any new features and any combination of features, particularly any combination of the features in the claims, even if such features or combinations are not explicitly stated in the claims or exemplary embodiments themselves.

[0179] List of reference numerals

[0180] 1 Quantum computing device

[0181] 2 Permanent magnet device

[0182] 3 Section

[0183] 4 Magnetization direction

[0184] 6 Trapped ions

[0185] 7 First axis

[0186] 7' Axis of symmetry

[0187] 8 Quantum computer

[0188] 9 Quantum computing device

[0189] 10 Chamber

[0190] 11 Connection

[0191] 12 External electronic device

[0192] 13 Classical computer

[0193] 14 First region

[0194] 15 Second region

[0195] 16 Intermediate region

[0196] 100 Ion trap

[0197] 21 First rf electrode

[0198] 22 Second rf electrode

[0199] 31 First dc electrode

[0200] 32 Second dc electrode

[0201] 41 First end cap electrode

[0202] 42 Second end cap electrode

[0203] 45 First separation cap electrode

[0204] 46 Second separation cap electrode

[0205] 47 Partition

[0206] 51 Spacer layer

[0207] 52 First substrate

[0208] 53 Second substrate

[0209] 54 Recess

[0210] 60 Yoke structure

[0211] d Distance

[0212] R i Inner radius

[0213] R o Outer radius.

Claims

1. A quantum computing device (1), comprising: - A permanent magnet device (2) configured to establish a magnetic field having different intensities 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, wherein, - The ion trap (100) has at least one partition (47) that is part of the first region (14) and the second region (15) for accommodating at least one ion crystal, and - The at least one ion crystal includes a plurality of trapped ions (6) arranged along the first axis (7).

2. The quantum computing device (1) according to claim 1, wherein, - The first region (14) and the second region (15) each include at least two cover electrodes arranged at respective end regions of the first region (14) and the second region (15).

3. The quantum computing device (1) according to one of claims 1 or 2, wherein, The at least one partition (47) includes: - A first radio frequency (rf) electrode (21) and a first direct current (dc) electrode (31) in the first region (14); and - A second rf electrode (22) and a second dc electrode (32) in the second region (15).

4. The quantum computing device (1) according to claim 3, wherein, - The first rf electrode (21) and the first dc electrode (31) are spaced apart from each other perpendicular to the first axis (7), and - The second rf electrode (22) and the second dc electrode (32) are spaced apart from each other perpendicular to the first axis (7), - The first rf electrode (21) is arranged above the second dc electrode (32), and - The first dc electrode (31) is arranged above the second rf electrode (22).

5. The quantum computing device (1) according to one of claims 3 to 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. The quantum computing device (1) according to claim 5, wherein, - The metal film has a thickness of at most 30 μm.

7. The quantum computing device (1) according to one of claims 1 to 6, wherein, - An intermediate region (16) is arranged between the first region (14) and the second region (15).

8. The quantum computing device (1) according to claim 7, wherein, - The intermediate region (16) includes 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).

9. The quantum computing device (1) according to one of claims 1 to 7, wherein, - The first region (14) includes a first substrate (52), and - The second region (15) includes a second substrate (53).

10. The quantum computing device (1) according to one of claims 7 to 9, wherein, - the at least one permanent magnet device (2) is arranged within the intermediate region (16), and / or - a soft magnetic material forming a yoke structure (60) is arranged within the intermediate region (16), or - the at least one permanent magnet arrangement (2) is arranged within the first region (14) and / or the second region (15), and / or - the soft magnetic material forming a yoke structure (60) is arranged within the first region (14) and / or the second region (15).

11. The quantum computing device (1) according to one of claims 9 to 10, wherein, - the first substrate (52) and the second substrate (53) have recesses (54) that extend in a vertical direction from an outer main surface of the first substrate (52) to an outer main surface of the second substrate (53) and extend in a lateral direction between the first rf electrode (21) and the first dc electrode (31).

12. The quantum computing device (1) according to one of claims 1 to 11, wherein, - the at least one permanent magnet arrangement (2) is arranged above the first region (14) and / or below the second region (15).

13. The quantum computing device (1) according to one of claims 1 to 12, wherein, - the ion trap (100) includes a plurality of partitions (47), - each partition (47) is configured to accommodate an ion crystal, and - the ion crystals are arranged along the first axis (7).

14. The quantum computing device (1) according to claim 13, wherein, - the ion crystals are configured to interact with each other via ion transport and / or photon links.

15. The quantum computing device (1) according to one of claims 1 to 14, wherein, - the permanent magnet device (2) includes a plurality of segments (3), namely, at least four segments (3), and - each segment (3) has a magnetization direction (4).

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

17. The quantum computing device (1) according to one of claims 15 or 16, wherein, the magnetization directions (4) of the segments (3) arranged at opposite regions point in opposite directions.

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

19. The quantum computing device (1) according to one of claims 1 to 18, further comprises: - at least one additional permanent magnet device (2), wherein, - the permanent magnet device (2) has a rotational 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.

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

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