Quantum Computing Devices and Quantum Computers

Abstract

A quantum computing device is provided that includes a permanent magnet device and a substrate. [Solution] The quantum computing device is configured to implement a planar Paul trap for trapping at least one ion crystal having a plurality of ions aligned along a predetermined line. Components of the quantum computing device comprising electrodes of the planar Paul trap for establishing an electrical trapping potential are disposed on a top surface of a substrate. The predetermined line is disposed above the top surface. A permanent magnet device establishes a magnetic field, the magnitude of which varies along the predetermined line. Further, a quantum computer comprising the quantum computing device is specified.

Description

[Technical Field]

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

[0002] In many quantum computing processes that use quantum computing arrangements, the arrangements are configured to trap quantum particles, such as ions. During operation, the trapped quantum particles form quantum bits, or qubits for short. To perform computations, the trapped quantum particles must be controlled and manipulated. For trapped quantum particles, interactions, such as Coulomb repulsion, can create coupling between neighboring trapped quantum particles, thus enabling entanglement. To perform quantum computing processes using trapped quantum particles, the trapped quantum particles must be individually controllable and addressable relative to one another.

[0003] Individual addressing of multiple trapped quantum particles, e.g., qubit registers, is desirable to have negligible crosstalk. However, crosstalk between adjacent trapped quantum particles is typically a source of error that is difficult to control in quantum computing processes and can hinder meaningful application, and therefore scalability, of quantum error correction protocols.

[0004] Therefore, one object to be achieved is to provide an improved quantum computing device, for example, a quantum computing device that is compact in design and / or alternatively easy to manufacture and / or alternatively allows improved controllability. A further object to be achieved is to provide a quantum computer using such a quantum computing device.

[0005] These objects are solved, inter alia, by the subject matter of claims 1 and 16. Advantageous embodiments and further developments are the subject matter of the dependent claims and can also be extracted from the following description and drawings. Summary of the Invention

[0006] First, the quantum computing device is described in detail.

[0007] According to at least one embodiment, the quantum computing device comprises a permanent magnet device. For example, the permanent magnet device is symmetric with respect to a plane of symmetry, in particular geometrically symmetric. This means that the geometry or shape of the permanent magnet device, respectively, is symmetric with respect to the plane of symmetry. The shape of the permanent magnet device may also have rotational symmetry, for example n-fold rotational symmetry, where n is at least 3, at least 4, at least 6, or at least 8.

[0008] In accordance with at least one embodiment, a quantum computing device includes a substrate, which may be an electrically insulating substrate, which may include or consist of sapphire, diamond, or a ceramic such as AlN.

[0009] According to at least one embodiment, a quantum computing device is configured to implement a planar Paul trap to trap at least one ion crystal having several ions aligned along a predetermined line. In other words, during operation, the quantum computing device, i.e., at least a portion thereof, constitutes a planar Paul trap. A Paul trap is also known as a quadrupole ion trap or a radio frequency (RF) trap. It is a type of ion trap that uses a dynamic electric field to trap charged particles.

[0010] The planar Paul trap is configured to trap at least one ion crystal having two or more ions aligned along a predetermined line, e.g., at least 8, or at least 20, or at least 100, and / or up to 1000 ions.

[0011] In accordance with at least one embodiment, the components of the quantum computing device that constitute the electrodes of the planar Paul trap for generating the electrical trapping potential, hereinafter simply referred to as the electrodes of the planar Paul trap, are disposed on the top surface of the substrate. In particular, all of the electrodes of the planar Paul trap that generate the electrical trapping potential are disposed on the top surface of the substrate.

[0012] For example, the top surface of the substrate is a flat top side. The substrate can be part of a planar Paul trap. The electrodes can be applied to the substrate by a deposition method, such as sputtering or evaporation. The thickness of the electrodes can be increased by using a galvanic process. The substrate can mechanically stabilize the electrodes. There can be an adhesion layer between the electrodes and the top side to improve adhesion of the electrodes to the top side.

[0013] For example, a planar Paul trap may include at least two RF electrodes, at least two DC electrodes, and at least two end cap electrodes, all of which may be disposed in a common electrode plane.

[0014] The electrodes of the planar Paul trap may be distinct from the permanent magnet device. Thus, the planar Paul trap may be a separate device of the quantum computing device that is distinct from the permanent magnet device. Alternatively, one or more components of the permanent magnet device also form the electrodes of the planar Paul trap, such that the planar Paul trap is at least partially formed by the permanent magnet device.

[0015] During operation, the electrodes of the planar Paul trap generate an oscillating electrical potential configured to trap at least one ion crystal, with some ions aligned parallel to a predetermined line and perpendicular to the predetermined line, also referred to herein as the radial direction. Effectively, at least one electrical potential well is created in which ions are trapped in all spatial directions and is formed such that ions are arranged back and forth along the predetermined line, e.g., in a linear configuration. Multiple ions trapped in the same potential well are referred to herein as an ion crystal.

[0016] The predetermined line, also called the trapping line, is defined by the potential generated by the planar Paul trap and therefore depends on the geometry of the planar Paul trap. Trapped ions are arranged along the predetermined line. For example, each of the ions in at least one ion crystal intersects and / or oscillates around the predetermined line. In other words, in a Paul trap, ions in at least one ion trap are arranged in an ion chain extending along the predetermined line. The predetermined line may be parallel to the top surface of the substrate.

[0017] Each electrode may be formed as a plate, sheet or film, with the main extension plane extending, for example, parallel to the upper surface.

[0018] The electrodes may be made of metal. For example, they may be made of Au or other materials, such as Cu. In this case, the electrodes may be coated with Au. Each electrode is in particular a continuous, uninterrupted metal element. For example, the extension of the electrode along its respective main extension plane is at most 300 mm, or at most 50 mm, or at most 10 mm, or at most 1 mm. The thickness of the electrode, measured perpendicular to the main extension plane, is, for example, at most 100 μm, or at most 50 μm.

[0019] In addition to the electrodes for the Paul trap, the quantum computing device may include components for powering the electrodes, such as a power supply and / or a control unit.

[0020] According to at least one embodiment, the quantum computing device is configured such that the predetermined line is located above the top surface, i.e., offset from the top surface and offset from the substrate. In particular, the predetermined line can be located above the electrodes of a planar Paul trap. This means that during operation, ions float above the top surface or electrodes of the planar Paul trap, respectively. For example, in a direction perpendicular to the top side, all electrodes of the Paul trap are located either in front of or behind the predetermined line, i.e., in front of or behind the ions.

[0021] For example, the average distance between the upper surface and a predetermined line measured in a direction perpendicular to the upper surface is at least 20 μm, or at least 100 μm. Additionally or alternatively, the minimum distance is at most 500 μm, or at most 200 μm.

[0022] In accordance with at least one embodiment, a permanent magnet device generates a magnetic field, the magnitude of which varies along a predetermined line.

[0023] The magnetic field is understood herein to be the magnetic flux density, and the magnitude of the magnetic field is therefore the absolute value of the magnetic flux density.

[0024] The magnetic field generated by the permanent magnet device may be or include, for example, a magnetic quadrupole field. Higher multipole moments may also be present. At the center of the magnetic field, the absolute value of the magnetic field may be zero. The center of the magnetic field may coincide with the geometric center of the permanent magnet device and / or the planar Paul trap. For example, the center of the magnetic field may be in the plane of symmetry of the permanent magnet device and / or on a predetermined line. The magnetic field may be point-symmetric about its center.

[0025] The magnitude of the magnetic field varies along a given line, meaning that the magnitude of the magnetic field at different locations on the given line is different from one another. The variation in the magnitude of the magnetic field along a given line is also referred to herein as the gradient of the magnetic field along the given line.

[0026] The change in the magnitude of the magnetic field can be monotonic, e.g., strictly monotonic, at least in part. For example, starting from the center of the magnetic field, the change in the magnetic field can be monotonic in both directions along a given line, or strictly monotonic. The direction of the magnetic field can change along a given line, or can remain constant along a given line.

[0027] In at least one embodiment, a quantum computing device includes a permanent magnet device and a substrate. The quantum computing device is configured to implement a planar Paul trap for trapping at least one ion crystal having ions aligned along a predetermined line. Components of the quantum computing device, comprising electrodes of the planar Paul trap for establishing an electrical trapping potential, are disposed on a top surface of the substrate. The predetermined line is disposed above the top surface. The permanent magnet device establishes a magnetic field, the magnitude of which varies along the predetermined line.

[0028] Trapped ions provide an excellent quantum system for quantum control and metrology. In the present invention, they are stored in a planar Paul trap and form at least one ion crystal oriented along a predetermined line. For certain tasks in quantum computing and metrology with trapped ions, individual control over single ions is desirable. When ions are manipulated with RF radiation, this single-ion control cannot be achieved by focusing the radiation because the wavelength typically exceeds the ion separation in the ion crystal by several orders of magnitude. Also, coupling between internal and external quantum states, as quantified by the Lamb-Dicke parameter, cannot be achieved with RF radiation.

[0029] The present invention is based, inter alia, on the idea of ​​using an inhomogeneous magnetic field provided by a permanent magnet device. This offers the possibility of individually addressing ions in frequency space by RF radiation. On the other hand, the superposition of the electric potential induced by the planar Paul trap and the magnetic field of the permanent magnet device makes the equilibrium position of the ions dependent on their respective quantum states. As a result, an effective spin-spin coupling is achieved due to the Coulomb interaction between the trapped ions. This allows for the entanglement of the ions' quantum states.

[0030] Furthermore, some quantum registers or ion crystals, respectively, may be advantageous for further scaling. This can be achieved using planar Paul traps, which allow scaling beyond several hundred ions and thus reaching total numbers of trapped ions that clearly exceed quantum supremacy, thus enabling the solution of computational problems previously inaccessible to classical supercomputers.

[0031] In summary, using the described quantum computing device for quantum information processing allows for individual single-qubit rotation with advanced addressing in frequency space and therefore low crosstalk, and introduces effective coupling between ions and therefore enables multi-qubit gates. Although this can also be used in conjunction with RF frequencies where addressing by focusing radiation is not an option due to the long wavelengths, 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, and simplifies the scaling of ion trap-based quantum computers.

[0032] In accordance with at least one embodiment, a permanent magnet device includes a plurality of permanently magnetized segments, which may all be formed identically within manufacturing tolerance limits.

[0033] The permanent magnet device may include at least 4, or at least 8, or at least 16, or at least 32 segments. Each segment may include or consist of a permanent magnetic material. For example, the permanent magnetic material may be a ferromagnetic material. The segments may each include or consist of the same material. For example, each segment may be integrally formed. Alternatively, each segment may be formed from at least two sub-segments, where the at least two sub-segments have the same material and / or magnetization properties.

[0034] According to at least one embodiment, 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. The vector field, and in particular the dipole moment of the permanent magnetic material, defines the respective magnetization direction. The dipole moment primarily refers to the magnetization direction.

[0035] In accordance with at least one embodiment, the segments are arranged such that the magnetization directions of at least some of the segments differ from one another, such that the permanent magnet device establishes a magnetic field having a field magnitude that varies along a predetermined line.

[0036] For example, the magnetization directions of each pair of directly adjacent segments differ from each other. The magnetization directions may differ from each other by at least 5°, or at least 10°, and / or at most 90°, or at most 45°. By way of example, if there are m segments, and m is an even natural number of at least 4, the magnetization directions of two directly adjacent segments are rotated by 360°·3 / m with respect to each other.

[0037] The vector field defined by the magnetization directions of the segments and their positions in space may be symmetric with respect to the above-mentioned plane of symmetry. In particular, this vector field may have the same symmetry as the geometry of the permanent magnet device. Alternatively, the vector field may be asymmetric with respect to the plane of symmetry and / or may have a different symmetry than the geometry of the permanent magnet device, or may even be asymmetric.

[0038] In accordance with at least one embodiment of the quantum computing device, the permanent magnet device includes NdFeB. In particular, the permanent magnet device includes NdFeB N52. Illustratively, each segment includes or consists of NdFeB, in particular NdFeB N52.

[0039] According to at least one embodiment, the segments are arranged in a Halbach arrangement, which is a special arrangement of permanent magnets that enhances the magnetic field on one side of the arrangement and cancels it to near zero on the other side. Specifically, this is achieved by having a spatially rotating pattern of the magnetization directions of the segments.

[0040] Particularly high magnetic fields and field gradients can be achieved using such Halbach arrays. Halbach arrays are particularly useful because the effective spin-spin coupling and the difference in resonance of neighboring ions depend on the inhomogeneity and magnitude of the magnetic field. Indeed, Halbach arrays allow for large gradients even when the distance between any surface (including the trap electrodes and magnet surfaces) and the trapped ion should be large, which is desirable for high-fidelity gates with trapped ions. This, combined with segmented traps, for example, allows for flexible trapping configurations, tuning the coupling constant between qubits to trap several registers, splitting and merging quantum registers, and generally scaling the power of ion trap-based quantum computers.

[0041] According to at least one embodiment, the permanent magnet device surrounds the planar Paul trap and / or its electrodes. That is, the planar Paul trap is a separate device from the permanent magnet device. In particular, the segments of the permanent magnet device are distinct from the electrodes of the planar Paul trap. For example, the permanent magnet device may have a ring shape or a polygonal contour or perimeter shape, respectively. Thus, the planar Paul trap may be surrounded by a ring-shaped or polygonal contour-shaped permanent magnet device. The permanent magnet device may then increase the magnetic field inside the ring or contour and cancel the magnetic field outside the ring or contour to near zero.

[0042] According to at least one embodiment, at least some of the electrodes of the planar Paul trap are formed by segments of a permanent magnet device.

[0043] According to at least one embodiment, at least some of the electrodes of the planar Paul trap, i.e., some or all of the electrodes of the planar Paul trap, are arranged in a common electrode plane. For example, all of the electrodes of the planar Paul trap that generate the electric trapping potential are arranged in the electrode plane. The top surface may be coincident with or parallel to the electrode plane.

[0044] The electrodes arranged in the electrode plane intersect with the electrode plane in particular, and the main extension plane of the electrodes extends, for example, parallel to the electrode plane or coincides with the electrode plane.

[0045] Some electrodes of a planar Paul trap may also be positioned at different heights relative to the top surface, for example, a stack of electrodes may be positioned on the top surface with an insulating layer separating every two electrodes in a direction perpendicular to the top surface.

[0046] According to at least one embodiment, the lateral extent of the planar Paul trap and / or substrate is at most 5 cm, or at most 2 cm, or at most 1 cm. The lateral extent is measured, for example, along the electrode plane. The thickness of the planar Paul trap or substrate, measured perpendicular to the electrode plane, can be at most 1 cm, or at most 0.5 cm, or at most 0.2 cm.

[0047] According to at least one embodiment, at least a portion of the permanent magnet device is disposed within a substrate, e.g., embedded within the substrate. For example, one or more or all of the segments of the permanent magnet device are disposed within the substrate. Regardless of whether the permanent magnet device surrounds a planar Paul trap, is disposed within the substrate, or is disposed elsewhere, the permanent magnet device may be ring-shaped or polygonally contoured. Thus, the segments may be arranged in a ring or polygonally contoured fashion.

[0048] According to at least one embodiment, the planar Paul trap is a linear planar Paul trap for trapping at least one ion crystal having ions aligned along a predetermined line or axis, respectively. Thus, the predetermined line is a predetermined line or a predetermined axis, respectively. Alternatively, the planar Paul trap can be a circular planar Paul trap.

[0049] According to at least one embodiment, the permanent magnet device establishes a substantially two-dimensional magnetic field that is primarily concentrated in the magnetic field plane. The center of the magnetic field may be in the magnetic field plane. The aforementioned symmetry plane of the permanent magnet device is, for example, perpendicular to the magnetic field plane. For example, all segments of the permanent magnet device are arranged in the magnetic field plane.

[0050] Starting from the magnetic field plane and moving in a direction perpendicular to the magnetic field plane, the magnetic field decays, e.g., the average magnitude of the magnetic field decays to approximately zero. The decay length depends on the dimensions of the permanent magnet device, e.g., the inner and / or outer diameter and / or thickness of the segments measured perpendicular to the magnetic field plane. In particular, the decay length is proportional to the inner and / or outer diameter and thickness of the segments.

[0051] For example, the average magnitude of the magnetic field has a full width half maximum (FWHM) in a direction perpendicular to the magnetic field plane of at least 1 μm, or at least 10 μm, and / or at most 10 mm, or at most 500 μm. For example, in this case, the average magnitude of the magnetic field outside the magnetic field plane, e.g., at a distance of 1 mm from the magnetic field plane, is at least one order of magnitude smaller than the average magnitude of the magnetic field in the magnetic field plane. In other words, the magnetic field plane is the main extension plane of the magnetic field magnitude.

[0052] For example, in a segment of a permanent magnet device arranged in the form of a ring, the main extension plane of the ring defining the xy plane, the magnetic flux density corresponding to the magnetic field

number

number

[0053] B R is the remanence of the segment, and R i is the inner diameter of the ring, and R o is the outer diameter of the ring, and x and y are the coordinates within the permanent magnet device. In this case, the magnetic field plane is the xy plane or main extension plane of the ring, respectively.

[0054] The magnetic field plane can extend parallel to the top surface of the substrate and / or the electrode plane. The segments are disposed or embedded, respectively, within the substrate. The magnetic field plane can extend through the substrate. The electrodes and / or the predetermined line can be offset from the magnetic field plane. However, due to the small distance of the predetermined line from the top surface, and thus the small distance of the predetermined line to the magnetic field plane (e.g., at most 100 μm), the magnitude of the magnetic field along the predetermined line is still sufficient to perform quantum computation.

[0055] According to at least one embodiment, the quantum computing device further includes a yoke structure for increasing the magnetic field and / or the change in magnetic field magnitude along a predetermined line established by the permanent magnet device. The yoke structure is positioned to increase the magnetic field or magnetic field gradient, particularly in the region of the trapped ions, i.e., along the predetermined line. For example, the yoke structure may include or consist of a soft magnetic material. It may have a coercivity of at most 1000 A / m, or at most 100 A / m. The soft magnetic material may be a ferromagnetic material configured to be magnetized by the magnetic field established by the permanent magnet device. The soft magnetic material may have a relative magnetic permeability of at least 300, or at least 1000, or at least 10,000. Illustratively, the soft magnetic material has a relative magnetic permeability of about 12,000. The saturation magnetic flux density of the soft magnetic material may be at least 0.5 T, or at least 2 T. For example, the soft magnetic material includes at least one of iron-cobalt, vanadium, manganese, niobium, silicon, and carbon.

[0056] The yoke structure may extend along or parallel to a predetermined line. For example, the yoke structure may include two portions spaced apart from each other in a direction parallel to the predetermined line. Each of the two portions may be elongated and may extend along or parallel to the predetermined line, for example. That is, the elongated portion may be oriented parallel to the predetermined line.

[0057] The steepness of the magnetic gradient can be further enhanced by using a yoke structure to concentrate the magnetic flux, for example, located in a region where the magnetic field magnitude of the permanent magnet device is already small and concentrating the field in a small cross-section of the yoke structure without exceeding the saturation magnetization of the yoke structure, thus substantially boosting the achievable gradient magnitude and enabling lower crosstalk, stronger coupling, and faster quantum gates.

[0058] In accordance with at least one embodiment, the yoke structure is disposed within or embedded in the substrate. In particular, at least two elongated portions of the yoke structure may be disposed within the substrate. For example, the yoke structure is embedded in the substrate.

[0059] Alternatively, the yoke structure may be disposed on the upper surface of the substrate. Similarly, the permanent magnet device, e.g., at least some segments thereof, may be disposed on the upper surface of the substrate.

[0060] In accordance with at least one embodiment, the yoke structure is at least partially formed by the electrodes of the planar Paul trap. For example, at least some of the electrodes of the planar Paul trap constitute part of the yoke structure. In other words, at least some of the electrodes of the Paul trap may include or consist of a soft magnetic material to increase the magnetic field or magnetic field gradient established by the permanent magnet device.

[0061] In accordance with at least one embodiment, the yoke structure includes or consists of an iron-cobalt alloy, which may include vanadium, for example, in a concentration of at least 1.5% and at most 3%.

[0062] According to at least one embodiment, the variation of the magnetic field along a predetermined line at the center of the magnetic field is at least 0.5 T / m, or at least 50 T / m, or at least 100 T / m, and / or up to 500 T / m.

[0063] According to at least one embodiment, the planar Paul trap is a segmented planar Paul trap. The planar Paul trap is configured, for example, to generate several electric potential wells. Each potential well is configured, for example, to host or trap an ion crystal, each ion crystal having several ions aligned along a predetermined line. An electrical potential wall separating two adjacent ion crystals can be disposed between the potential wells.

[0064] All features disclosed herein for one ionic crystal are also disclosed for all further ionic crystals.

[0065] The individual predetermined lines assigned to different ion crystals can all be straight lines, e.g., they all coincide with the same straight line. Alternatively, the individual predetermined lines assigned to individual ion crystals can be different from one another, e.g., they can be offset from one another and / or at different heights relative to the top surface of the substrate. The individual lines can still be parallel to one another.

[0066] The potential wells and / or ion crystals are arranged behind each other, for example, in a direction parallel to the predetermined lines or in a direction parallel to one of the respective predetermined lines.

[0067] According to at least one embodiment, a quantum computing device is configured to enable interactions between ion crystals via ion transport and / or photonic links. For example, photons emitted by ions in one ion crystal may interact with ions in an adjacent ion crystal. Alternatively, by changing the potential wall between two adjacent potential wells, one or more ions may be moved from one ion crystal to an adjacent ion crystal. For example, the potential wall may be made shallower and / or narrower so that ions hop from one ion crystal to an adjacent ion crystal.

[0068] Planar segmented traps allow for a large number of registers that can be independently controlled by RF, but can also interact by ion transport or photonic links.

[0069] According to at least one embodiment, the segmented planar Paul trap is configured to merge two adjacent potential wells into a larger potential well, e.g., the potential wall between two adjacent potential wells can be resolved to create one larger potential well from two smaller potential wells.

[0070] According to at least one embodiment, a segmented planar Paul trap is configured to divide a potential well into two adjacent smaller potential wells. For example, a potential wall can be created within the potential well such that two smaller potential wells are separated by the potential wall.

[0071] The terms "smaller" and "larger" used in conjunction with a potential well refer to a smaller or larger extent of the potential well, particularly in a direction parallel to a given line.

[0072] According to at least one embodiment, a planar Paul trap includes an inner electrode structure, two outer electrode structures, and two intermediate electrode structures, each of which may include or consist of multiple spaced apart electrodes, or may consist of one single, continuous electrode.

[0073] According to at least one embodiment, the inner electrode structures are disposed between the intermediate electrode structures, and the intermediate electrode structures are disposed between the outer electrode structures, e.g., in a lateral direction parallel to the top surface or electrode surface, respectively, and perpendicular to a predetermined line.

[0074] According to at least one embodiment, the electrode structures each extend parallel to a predetermined line, for example, each electrode structure is an elongate structure with a main extension direction of the electrode structure parallel to the predetermined line.

[0075] According to at least one embodiment, the outer electrode structures each include at least three electrodes: two end electrodes and at least one central electrode, the at least one central electrode being disposed between the two end electrodes in a direction parallel to the predetermined line. The inner and intermediate electrode structures may each consist of only one electrode elongated in a direction parallel to the predetermined line.

[0076] According to at least one embodiment, the inner electrode structure includes at least one electrode. The intermediate electrode structures each include at least one electrode. The electrodes of the inner and intermediate electrode structures extend, for example, in a direction parallel to a predetermined line. This allows these electrodes to extend across at least three electrodes of the outer electrode structure in a direction parallel to the predetermined line.

[0077] According to at least one embodiment, the intermediate electrode structure is an RF electrode structure. During operation, the RF electrode structure is supplied with an AC voltage. With the help of the RF electrode structure, an oscillating potential is generated to confine ions in a direction perpendicular to the predetermined line, i.e., in the radial direction.

[0078] According to at least one embodiment, the inner electrode structure is a DC electrode structure, for example, the inner electrode structure is grounded during operation of the planar Paul trap.

[0079] According to at least one embodiment, in each outer electrode structure, at least one central electrode is controllable independently of the end electrodes. That is, at least one central electrode can be or is set to a different potential than the end electrodes. This allows a potential to be created that traps ions in a direction parallel to a predetermined line. Thus, overall, a potential well is created to host an ion crystal with some ions aligned along the predetermined line.

[0080] The end electrodes may, for example, constitute end cap electrodes of a planar Paul trap. At least one central electrode may, for example, constitute a DC electrode of the planar Paul trap. For example, when the central electrode is at a lower potential than the end electrodes, a potential well is formed to host the ion crystal.

[0081] According to at least one embodiment, each outer electrode structure comprises at least five electrodes.

[0082] According to at least one embodiment, in each outer electrode structure, at least the first and second central electrodes are controllable independently of the third central electrode, i.e., the third central electrode can be set to a different potential than the first and second central electrodes. For example, the potential of the third central electrode can be varied.

[0083] The third central electrode is disposed between the first and second central electrodes in a direction parallel to the predetermined line, e.g., adjacent to the first and second central electrodes. The central electrode is disposed between the end electrodes in a direction parallel to the predetermined line. In this manner, at least two potential wells can be created, positioned behind each other in a direction parallel to the predetermined line. Each potential well is configured to host an ion crystal, i.e., to confine a plurality of ions aligned along the predetermined line.

[0084] For example, the first and second central electrodes may each be assigned a potential well such that the assigned potential well, e.g., its minimum, is aligned with the respective central electrode in a direction parallel to the predetermined line. The third central electrode may be assigned a potential wall between the potential wells. The potential wall may be aligned with the third central electrode in a direction parallel to the predetermined line. For example, the third central electrode generates a potential wall.

[0085] During operation, the third central electrode can be at the same potential as the end electrodes or at the same potential as the first and second central electrodes of each outer electrode structure. For example, the potential of the third central electrode can be variable between the potential of the end electrodes and the potential of the first and second central electrodes. The potential of the third central electrode can be controllable independently of the potential of the end electrodes to break down or establish potential barriers between potential wells. The first and second central electrodes can be grounded, for example, during operation.

[0086] The electrodes of the two outer electrode structures that correspond to each other may be electrically connected so that they are at the same potential.

[0087] A planar Paul trap can also be formed with multiple electrodes arranged on the top side of a substrate in a pixelated arrangement. For example, each electrode can be rectangular or square, and the electrodes can be arranged in a rectangular pattern on the top surface. The electrodes can all be individually and independently controllable using radio frequency (RF) or DC voltages.

[0088] According to at least one embodiment, a quantum computing device includes at least two permanent magnet devices. Each of the two permanent magnet devices may include several segments, each having a magnetization direction. All features disclosed with respect to one permanent magnet device may also be disclosed with respect to the other permanent magnet device. In particular, each permanent magnet device may be a Halbach array and / or may be integrated into a substrate.

[0089] According to at least one embodiment, the permanent magnet devices are configured to each generate a magnetic field. For example, for each permanent magnet device, the magnitude of the respective magnetic field varies along a predetermined line. By using two such permanent magnet devices, a zone of high control and / or steep magnetic field variation can be combined with a zone of low and / or nearly constant magnetic field for uncritical ion transport. For example, the permanent magnet devices are arranged one behind the other in a direction parallel to the predetermined line.

[0090] According to at least one embodiment, each potential well or ion crystal is assigned an individual permanent magnet arrangement.

[0091] According to at least one embodiment, each permanent magnet device is configured such that the magnitude of its magnetic field varies along a predetermined line of the assigned ion crystal, e.g., the center of each permanent magnet device, or the center of the magnetic field established by that permanent magnet device, is aligned with an assigned potential well (e.g., its minimum) parallel and / or transverse to the respective predetermined line.

[0092] For example, the center of each permanent magnet device, or the center of the magnetic field established by that permanent magnet device, is aligned with the central electrode of the outer electrode structure in a direction parallel to a predetermined line. The center of a first permanent magnet device may be aligned with the first central electrode, and the center of a second permanent magnet device may be aligned with the second central electrode. In a top plan view, the centers of the permanent magnet devices may overlap with the inner electrode structure.

[0093] In accordance with at least one embodiment, the quantum computing device includes a vacuum chamber. During operation, ions are trapped within the vacuum chamber. The planar Paul trap or its electrodes may also be disposed within the vacuum chamber. The vacuum chamber may be an ultra-high vacuum chamber, an extremely high vacuum chamber, and / or a cryostat.

[0094] According to at least one embodiment, the permanent magnet device is located outside the vacuum chamber. This can be advantageous because creating an ultra-high vacuum (UHV) can include steps such as baking, which may be incompatible with many magnetic materials, especially those with low Curie temperatures. Even when the permanent magnet device is located outside the vacuum chamber, it still generates a sufficiently high magnetic field or magnetic field gradient in the ion region. Alternatively, the permanent magnet device can also be located inside the vacuum chamber. An optional yoke structure can be located inside or outside the vacuum chamber to increase the magnetic field (gradient).

[0095] Next, a quantum computer is identified, which includes the quantum computing device described herein, and therefore, all features disclosed for a quantum computing device are also disclosed for a quantum computer, and vice versa.

[0096] 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.

[0097] According to at least one embodiment, the quantum computer further comprises a cooling and / or read-out system, e.g., laser-based. The cooling and / or read-out system is configured to cool the ions to prepare them in a low motional state and trap them in their respective ground states. The read-out system is configured to determine the state of each ion. For example, the ions are cooled and / or read-out by impinging a laser beam or scattering photons of a laser beam, respectively. [Brief explanation of the drawings]

[0098] Hereinafter, a quantum computer device and a quantum computer will be described in more detail based on exemplary embodiments, with reference to the drawings. The accompanying drawings are included to provide a further understanding. In the drawings, elements relating to the same structure and / or function may be referred to by the same reference numerals. It should be understood that the embodiments shown in the figures are exemplary representations and are not necessarily drawn to scale. To the extent that elements or components in different figures correspond to each other in terms of their functionality, the description will not be repeated for each of the following figures. For clarity, elements may not appear with corresponding reference numerals in all figures. [Figure 1] FIG. 1 illustrates a first exemplary embodiment of a quantum computing device. [Figure 2]FIG. 2 shows an exemplary embodiment of a planar Paul trap in different views. [Figure 3] FIG. 3 shows an exemplary embodiment of a planar Paul trap in different views. [Figure 4] FIG. 4 shows a different view of a second exemplary embodiment of a quantum computing device. [Figure 5] FIG. 5 shows a different view of a second exemplary embodiment of a quantum computing device. [Figure 6] FIG. 6 shows a further exemplary embodiment of a planar Paul trap. [Figure 7] FIG. 7 illustrates a further exemplary embodiment of a quantum computing device. [Figure 8] FIG. 8 illustrates a further exemplary embodiment of a quantum computing device. [Figure 9] FIG. 9 illustrates an exemplary embodiment of a quantum computer. DETAILED DESCRIPTION OF THE INVENTION

[0099] FIG. 1 illustrates a first exemplary embodiment of a quantum computing device 1. The quantum computing device 1 includes a permanent magnet arrangement 2. The permanent magnet arrangement 2 includes 16 permanently magnetized segments 3. The segments 3 surround a planar Paul trap 100. The planar Paul traps 100 are configured to trap ion crystals 6 a each having a plurality of ions 6 aligned along a predetermined line 7, i.e., a trapping line 7. In this exemplary embodiment, the planar Paul trap 100 is a linear planar Paul trap for trapping ions 6 along the line 7. The line 7 defines the x-axis.

[0100] The permanent magnet device 2 has the shape of a ring, and the planar Paul trap 100 is arranged in the center of the ring. The thickness of each segment 3 is, for example, 100 μm. The ring extends in the xy plane. Each segment 3 has the shape of a ring segment. The minimum distance between two opposing segments 3, i.e., the inner ring diameter 2Ri, is approximately 0.2 mm. Furthermore, each segment 3 has an extent of approximately 0.2 mm along the corresponding minimum distance. The outer diameter 2Ro of the permanent magnet device 2 is therefore approximately 0.6 mm. The edges of the mutually opposing, directly adjacent segments 3 have a mutual distance of, for example, approximately 10 μm.

[0101] Furthermore, each segment 3 has a magnetization direction 4, which is depicted as an arrow in the segment 3 in FIG. 1 . The segments are each formed of, for example, NdFeB N52. 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 predetermined line 7 extends through the center of the permanent magnet device 2 and intersects two opposing segments 3. Here, the magnetization directions 4 of these two segments 3 are parallel to the predetermined line 7.

[0102] Each magnetization direction 4 forms an angle with a given line 7. All of these angles are formed differently from one another. For example, the angles of two directly adjacent segments 3 differ from one another by 67.5°. The magnetization directions 4 are all in the xy plane.

[0103] The permanent magnet device of Figure 1 is a Halbach arrangement that establishes a quadrupole field with a field magnitude that varies along a predetermined line 7. In other words, the field has a field gradient along the predetermined line 7. For example, each of the trapped ions positioned along the predetermined line will therefore see a different magnetic field.

[0104] Using the permanent magnet device shown in Figure 1, the ideal magnetic flux density is

number

number

[0105] The remanence B of each segment 3 R is, for example, 1 T. As can be extracted from this ideal magnetic flux density, the magnetic field is a two-dimensional magnetic field, mainly concentrated in the xy plane, which constitutes the magnetic field plane.

[0106] Figures 2 and 3 show two different views of the planar Paul trap 100 of Figure 1. The planar Paul trap 100 includes a plurality of electrodes 20, 30, 40a, 40b configured to generate electrical potentials to trap ions 6 along a predetermined 7. The electrodes 20, 30, 40a, 40b are all disposed on a top side 51 of a substrate 50 and all lie in a common electrode plane EP. Figure 2 is a plan view of the top side 51, while Figure 3 is a cross-sectional view perpendicular to the top side 51.

[0107] The electrodes 20, 30, 40a, and 40b are made of, for example, Au. The substrate 50 may be a sapphire substrate.

[0108] The electrodes 20, 30, 40a, 40b are part of an inner electrode structure 32, two intermediate electrode structures 22, and two outer electrode structures 42. The inner electrode structure 32 is formed by a continuous, elongated electrode 30 extending parallel to the predetermined line 7. The intermediate electrode structures 22 are each formed by a continuous, elongated electrode 20 also extending parallel to the predetermined line 7. The inner electrode structures 32 are thereby arranged between the intermediate electrode structures 22 in a transverse direction perpendicular to the direction of the predetermined line 7. The intermediate electrode 20 is an RF electrode to which an AC voltage is supplied during operation. The inner electrode 30 is, for example, a DC electrode that is grounded during operation. Alternatively, the inner electrode 30 can be an RF electrode. With the help of the inner electrode 30 and the intermediate electrode 20, an oscillating electrical potential is generated, which in particular confines ions radially, i.e., perpendicular to the predetermined line 7.

[0109] Each outer electrode structure 42 includes three electrodes 40a, 40b. The inner electrode structure 32 and the intermediate electrode structure 22 are laterally disposed between the outer electrode structures 42. The electrodes 40a, 40b of the outer electrode structures 42 are disposed behind the other in a line, where this line is parallel to the predetermined line 7. The end electrodes 40a of each outer electrode structure 42 constitute end cap electrodes, which are at the same potential, for example, during operation. The central electrode 40b disposed between the end electrodes 40a is grounded, for example, during operation.

[0110] The potential V(x,0,0) along the x-axis (defined line 7) generated by electrodes 20, 30, 40a, 40b is shown in the graph of Figure 2. Collectively, a potential well W is formed that traps ions 6. Ions 6 within potential well W form a linear ion crystal 6a.

[0111] The diagram of FIG. 2 also shows the magnitude of the magnetic field on the x-axis, ie the magnitude of the magnetic flux density |B(x,0,0)|, generated by the permanent magnet arrangement 2 of FIG.

[0112] As best shown in FIG. 3, a yoke structure 60 is embedded in the substrate 50. The yoke structure 60 has two portions spaced apart from each other in a direction parallel to the predetermined line 7. Each portion of the yoke structure 60 is an elongated element and is made of a soft magnetic material. The yoke structure 60 increases the magnetic field along the predetermined line 7 and its gradient.

[0113] The ions 6 shown in FIGS. 1 to 3 are, for example, 171Yb+ ions. The distance d between directly adjacent trapped ions is, for example, approximately 3 μm. The degeneracy of the excited quantum states is resolved by the magnetic field generated by the permanent magnet device 2. The energy of the π-transition from the ground quantum state to the excited m=0 quantum state weakly depends on the magnetic field experienced by the ions. Similarly, the energy of the σ±-transition from the ground quantum state to the excited m=±1 quantum state depends on the magnetic field experienced by the ions. Since the magnitude of the magnetic field depends on the position of the ions 6 along the predetermined line 7, the energy of the transition depends on the position along the predetermined line 7. For example, for each of two adjacent ions 6, the frequency difference between the σ+ / − transitions is at least 1 MHz and at most 100 MHz. Furthermore, for each of two adjacent ions 6, the frequency difference between the σ+ / − transitions is at least 0.001 MHz and at most 10 MHz.

[0114] Furthermore, due to the shape of the potential well W along the predetermined line 7 and the magnetic field provided by the permanent magnet arrangement 2, the equilibrium positions of the ions 6 depend on their respective quantum states. Thus, an effective spin-spin coupling between the ions 6 due to Coulomb interactions is achieved, which allows the quantum states of the ions 6 to be entangled.

[0115] In particular, the coupling strength between two directly adjacent trapped ions 6 depends on the square of the magnetic field gradient. Furthermore, the relaxation time, in particular the spin relaxation time T2, is inversely proportional to the decoherence rate. Therefore, to provide multi-qubit gates, the magnetic field gradient must be relatively high to provide a large number of gates in a given time. This can be achieved by the permanent magnet devices described herein.

[0116] 4 and 5 show further exemplary embodiments of a quantum computing device 1. In contrast to the quantum computing device of FIG. 1, permanent magnet devices 2 each including a plurality of permanently magnetized segments 3 are disposed or embedded in a substrate 50. The permanent magnet devices 2 are indicated by dashed lines in FIG. 4.

[0117] A magnet field plane BP, in which the magnetic field established by the permanent magnet device 2 primarily resides, is within the substrate 50. The predetermined line 7 is therefore offset from the magnetic field plane BP. However, because the distance of the predetermined line 7 or the ions 6 to the magnetic field plane BP, respectively, is small, e.g., less than 150 μm, the ions 6 still feel a sufficient magnetic field to allow proper quantum computing operation.

[0118] Figure 6 shows a further exemplary embodiment of a planar Paul trap 100 that can be used, for example, with an integrated permanent magnet configuration such as that shown in Figures 4 and 5 or an enclosed permanent magnet configuration such as that shown in Figure 1. In contrast to the planar Paul traps 100 of Figures 2 through 5, the planar Paul trap 100 of Figure 6 includes an outer electrode structure 42 with five electrodes 40a, 40b, and 40c, respectively, arranged front to back in a direction parallel to a predetermined line 7. Each outer electrode structure 42 includes two end electrodes 40a and three central electrodes 40b and 40c.

[0119] The third central electrode 40c is disposed between the first central electrode 40b and the second central electrode 40b. The third central electrode 40c can be controlled independently of the other central electrodes 40b. For example, during operation, the third central electrode 40c can be set to the same potential as the end electrode 40a. Here, the first and second central electrodes 40b can be grounded.

[0120] The result is a potential V(x,0,0) in the x-direction, as shown in Figure 6. Two adjacent potential wells W are created, one behind the other in a direction parallel to the predetermined line 7. Each potential well W confines and hosts an ion crystal 6a, 6b containing a plurality of ions 6 aligned along the predetermined line 7. The two potential wells W are separated from each other by a potential wall, primarily due to the third central electrode 40c.

[0121] The ion crystals 6a and 6b in FIG. 6 can interact with each other, for example, through a photonic link. Alternatively, the ion crystals 6a and 6b can interact with each other through ion transport. For example, by changing the potentials of the electrodes 40a, 40b, and 40c of the outer electrode structure 42, the shape of the potential V(x,0,0) in the x-direction can be changed, and ions 6 can be transported from one ion crystal 6a to the adjacent ion crystal 6b. As an example, if the third central electrode 40c is set to the same potential as the first and second central electrodes 40b, the two potential wells W shown in FIG. 6 merge into one larger potential well, and the two separate ion crystals 6a and 6b can then merge into one large ion crystal 6a.

[0122] 7 shows one exemplary embodiment of a quantum computing device 1. Here, two permanent magnet devices 2 are embedded in the substrate 50 of the planar Paul trap 100, each in the form of a Halbach array. The permanent magnet devices 2 are thereby arranged behind each other in a direction parallel to a predetermined line 7, with the centers of the permanent magnet devices 2 overlapping the predetermined line 7 in a plan view of the upper surface 51. The two permanent magnet devices 2 are arranged such that each of them is uniquely assigned to a potential well W and a respective ion crystal 6a, 6b.

[0123] In the exemplary embodiment of Figure 8, the permanent magnet device 2 surrounds the planar Paul trap 100 in the form of a polygonal outline. Each segment 3 has a square shape. Adjacent segments 3 are rotated relative to each other.

[0124] 8, the Paul trap 100 is disposed in a chamber 10, and the chamber 10 is surrounded by a permanent magnet device 2. The chamber 10 is, for example, an ultra-high vacuum chamber.

[0125] One exemplary embodiment of a quantum computer 8 is shown in Figure 9. The quantum computer 8 comprises a quantum computing device 1 according to one of the exemplary embodiments described herein. A planar Paul trap 100 is connected to external components of the quantum computer 8 through a chamber 10 by a number of connections 11. For example, connections 11 connect the planar Paul trap 100 to external control electronics 12 and a classical computer 13.

[0126] The quantum computing device 1 is configured to trap ions, manipulate the trapped ions, and perform measurements. To this end, the quantum computing device 1 may include, in addition to the permanent magnet device 2 and any components of the planar Paul trap 100, a light guide and / or internal electronics, including electronic devices. The electronic devices may include circuitry, integrated electronics, a power supply, and / or detectors, such as photon detectors and / or charge detectors, controllers, etc. Illustratively, the internal electronics are provided for preprocessing. For example, these components enable measurement of the respective states of the ions and enable gating operations on the ions. Thus, the quantum computing device 1 is configured to trap ions and perform operations and measurements on the trapped ions.

[0127] The Paul trap 100 is mounted in a chamber 10, which may be an ultra-high vacuum chamber, an extremely high vacuum chamber, and / or a cryostat. 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 the chamber 10 (not shown here).

[0128] Quantum computing device 1, in particular Paul trap 100, is connected to external electronics 12 via connection 11. External electronics 12 may be located at least partially inside chamber 10 and partially outside chamber 10. Furthermore, external electronics 12 is connected to a classical computer 13.

[0129] The external electronics 12 may include, for example, 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).

[0130] Additionally, the external electronics 12 may further comprise at least one laser-based system configured to cool the trapped ions, and the laser-based system may further be configured to excite and / or read out particular states of the trapped ions.

[0131] Classical computer 13 is configured to provide and receive, for example, digital signals that correspond to control signals used to operate on qubits / ions as well as measurement signals that correspond to the states of the qubits.

[0132] External electronics 12 is configured, among other things, to convert digital signals to analog signals and vice versa, and thus to provide converted analog signals for manipulating ions (qubits) to quantum computing device 1. Furthermore, external electronics 12 is configured to process measured analog signals from quantum computing device 1 to classical computer 13, or to directly initiate any response signal generated by control electronics 12.

[0133] Classical computer 13 is illustratively configured with a particular algorithm, i.e., a predefined quantum computation that solves a particular problem. Classical computer 13 is then configured to translate compiled code corresponding to the algorithm into commands for quantum computing device 1. The commands are then transmitted to quantum computing device 1 via external control electronics 12. Additionally, classical computer 13 is configured to receive measured results of the particular algorithm.

[0134] 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.

[0135] The present invention is not limited to the exemplary embodiments described therein, but rather encompasses any novel feature and any combination of features, and in particular includes any combination of features in the claims, even if that feature or combination itself is not explicitly set forth in the claims or exemplary embodiments. [Explanation of symbols]

[0136] Reference Code List: 1. Quantum computing device 2. Permanent magnet device 3 segments 4 Magnetization direction 6. Ion 6a, 6b Ion Crystal 7 Default Lines 8. Quantum Computers 10 Chambers 11 Connection 12 Control electronic devices 13 Classical Computers 20 electrodes 22 Intermediate electrode structure 30 electrodes 32 Inner electrode structure 40a, b, c electrodes 42 Outer electrode structure 50 boards 51 Top side 60 yoke structure 100 Pole Trap Ri inner radius Ro outer radius BP magnetic field EP electrode surface W potential well V(x,y,z) potential B(x,y,z) magnetic flux density

Claims

1. 1. A quantum computing device, comprising: a permanent magnet device; a substrate; the quantum computing device is configured to implement a planar Paul trap to trap at least one ion crystal having a plurality of ions aligned along a predetermined line; components of the quantum computing device that form electrodes of the planar Paul trap for generating an electrical trapping potential are disposed on a top surface of the substrate; the predetermined line is disposed above the upper surface; the permanent magnet device establishes a magnetic field, the magnitude of the magnetic field varying along the predetermined line; Quantum computing device.

2. the permanent magnet device comprises a plurality of permanently magnetized segments; Each segment has a magnetization direction, The segments are arranged in a Halbach array.

10. The quantum computing device of claim 1.

3. the permanent magnet device surrounds the planar Paul trap in the form of a ring or in the form of a polygonal contour; 3. The quantum computing device of claim 1 or 2.

4. All electrodes of the planar Paul trap are arranged on a common electrode plane (EP).

3. The quantum computing device of claim 1 or 2.

5. At least a portion of the permanent magnet device is disposed on the substrate.

5. A quantum computing device according to any one of claims 1 to 4.

6. The quantum computing device further comprises: a yoke structure for increasing the magnetic field and / or the change in the magnitude of the magnetic field along the predetermined line established by the permanent magnet arrangement; 6. The quantum computing device of claim 1, comprising:

7. the yoke structure is disposed on the substrate; 6. A quantum computing device according to any one of claims 1 to 5.

8. the yoke structure includes a soft magnetic material; 7. The quantum computing device of claim 6.

9. the planar Paul trap is a segmented planar Paul trap configured to generate a plurality of potential wells; Each potential well is configured to host an ion crystal having a plurality of ions aligned along a predetermined line.

9. A quantum computing device according to any one of claims 1 to 8.

10. the quantum computing device is configured to enable interaction between the ion crystals by ion transport and / or photonic links; 10. The quantum computing device of claim 9.

11. The segmented planar Paul trap comprises: merging two adjacent potential wells into a larger potential well, and / or Splitting one potential well into two adjacent smaller potential wells; It is configured as follows:

11. A quantum computing device according to claim 9 or 10.

12. The planar Paul trap comprises an inner electrode structure, two outer electrode structures, and two intermediate electrode structures; the inner electrode structure is disposed between the intermediate electrode structures, and the intermediate electrode structure is disposed between the outer electrode structures; the electrode structure extends parallel to the predetermined line; Each of the outer electrode structures includes at least three electrodes: two end electrodes and at least one central electrode disposed between the end electrodes in a direction parallel to the predetermined line; the inner electrode structure comprises at least one electrode, and the intermediate electrode structures each comprise at least one electrode; the intermediate electrode structure is an RF electrode structure supplied with an AC voltage; In each outer electrode structure, the at least one central electrode is controllable independently of the end electrodes to generate at least one potential well for hosting an ion crystal having a plurality of ions aligned along the predetermined line.

12. A quantum computing device according to any one of claims 1 to 11.

13. Each outer electrode structure comprises at least five electrodes; In each outer electrode structure, at least the first and second central electrodes are controllable independently of a third central electrode disposed between the first and second central electrodes to generate at least two potential wells disposed behind each other in a direction parallel to a predetermined line, and each potential well is configured to host an ion crystal. Quantum computing device according to claim 12 in combination with claim 10 or 11.

14. The quantum computing device includes: at least two permanent magnet devices; the permanent magnet devices are each configured to generate a magnetic field; 14. A quantum computing device according to any one of claims 1 to 13.

15. Each ion crystal is assigned an individual permanent magnet device, each permanent magnet device is configured to vary the magnitude of a magnetic field along the predetermined line associated with the assigned ion crystal; 15. The quantum computing device of claim 14 in dependence upon claim 9.

16. 1. A quantum computer configured to perform quantum computations, comprising:

16. A quantum computing device comprising: a quantum computing device according to any one of claims 1 to 15; Quantum computer.

17. The quantum computer further comprises: a laser-based cooling and / or readout system; 17. The quantum computer of claim 16.

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