Quantum computing configuration and quantum computer

Abstract

A quantum computing configuration (1) is defined, the quantum computing configuration having a permanent magnet configuration (2) configured to establish magnetic fields having different magnitudes at different positions on a first axis (7), a space (5) for at least two trapped quantum particles (6) arranged along the first axis (7), and a soft magnetic material (61) surrounded by the permanent magnet configuration (2) configured to enhance the magnetic field established by the permanent magnet configuration (2). Further, a quantum computer (8) having the quantum computing configuration (1) is defined.

Description

[Technical Field]

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

[0002] In many quantum computing processes using quantum computing configurations, devices may be configured to trap captured quantum particles. To perform computations, the trapped quantum particles must be controlled and manipulated. For charged trapped quantum particles, interactions, such as Coulomb repulsion, create bonds between neighboring trapped quantum particles, allowing for entanglement. Therefore, to perform quantum computing processes using trapped quantum particles, the trapped quantum particles must be individually controllable and addressable from one another.

[0003] Individual addressing of multiple trapped quantum particles, such as in a qubit register, is desirable with negligible crosstalk. However, crosstalk between neighboring trapped quantum particles is typically a difficult source of error to control in quantum computing processes and can hinder the meaningful application and, therefore, scalability of quantum error correction protocols. Summary of the Invention

[0004] Therefore, a problem to be solved is to specify a quantum computing configuration with improved controllability, and further, a quantum computer having such a quantum computing configuration is defined.

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

[0006] According to at least one embodiment, a quantum computing configuration includes a permanent magnet configuration configured to establish a magnetic field having different magnitudes for different positions on a first axis. Illustratively, the magnitude of the magnetic field varies along the first axis for different positions on the first axis. The magnitude is, for example, symmetrical about the center of the permanent magnet configuration along the first axis. That is, for example, there are two points on the first axis that have the same magnitude.

[0007] The permanent magnet configuration has a main extension plane, and a first axis extends along the main extension plane. The first axis is an imaginary axis. The first axis is, for example, an axis of symmetry in the main extension plane. That is, the first axis divides the permanent magnet configuration into two halves in a cross-sectional view along the main extension plane, and the shapes of the two halves are essentially the same. "Essentially the same" exemplarily means that due to manufacturing tolerances of the permanent magnet configuration, the halves, for example, the cross-sectional areas of the halves, may differ from each other by at most 5% or at most 1%.

[0008] The permanent magnet arrangement is configured to generate a multipole magnetic field, in particular a quadrupole magnetic field, with the magnitude of the magnetic field vanishing at the center of the permanent magnet arrangement, e.g., approximately 0 T. Due to the multipole magnetic field, in particular the quadrupole magnetic field, the magnitude of the magnetic field varies for different positions on the first axis.

[0009] In such a permanent magnet configuration, the magnitude of the magnetic field varies continuously along the first axis, i.e., starting from the center, for different positions on the first axis, and therefore the magnitude of the magnetic field for different positions on the first axis is characteristic of a magnetic field gradient along the first axis.

[0010] The magnetic field is represented by a magnetic flux density, and the absolute value of the magnetic flux density corresponds to the magnitude of the magnetic field for a given position on the first axis.

[0011] The components of the magnetic field correspond to the components of a vector, and the vector can point in any direction relative to the first axis. That is, at least some of the vectors of the magnetic field for different positions on the first axis can have different angles relative to the first axis. For example, at least some of the vectors of the magnetic field can point radially or axially relative to the first axis.

[0012] For example, for different positions on the first axis, at least some of the vectors of the magnetic field point in the same radial and / or axial direction of the first axis. Alternatively, or in addition, at least some of the vectors of the magnetic field are rotated radially of the first axis relative to each other.

[0013] The distribution of the magnetic field magnitude is symmetrical along the first axis relative to the center of the permanent magnet configuration. Illustratively, the first axis is divided into two halves by the center of the permanent magnet configuration. The magnetic field magnitude has a negative gradient in one half and a positive gradient in the other half. The magnetic field gradient increases along the first axis, e.g., approximately linearly, with respect to the magnetic field magnitude along the first axis. Due to manufacturing tolerances of the permanent magnet configuration, illustratively, there may be a deviation from linearity of up to 5% within the central region. That is, the magnetic field gradient is approximately constant along the first axis starting from the center.

[0014] According to at least one embodiment, a quantum computing configuration has a space for at least two trapped quantum particles arranged along a first axis, i.e., during operation of the quantum computing configuration, the at least two trapped quantum particles are arranged along the first axis, and illustratively, the space has a main direction of extension extending along the first axis.

[0015] For example, the space is surrounded by a permanent magnet configuration. The space is defined as an area or volume surrounded by the permanent magnet configuration, in which quantum particles are trapped during operation of the quantum computing configuration. Illustratively, during operation of the quantum computing configuration, the trapped quantum particles are arranged linearly next to each other along a first axis. In particular, during operation of the quantum computing configuration, more than two trapped quantum particles are arranged along the first axis, e.g., at least 8, at least 20, or at least 100, and / or at most 1000.

[0016] The trapped quantum particles may be represented, for example, by energy levels in atoms or molecules, or by the spin, charge, magnetic flux, or phase of electrons and / or nuclei in superconductors, or by the topological quantum numbers of anyons in topologically protected systems.

[0017] For example, the space is located in a vacuum environment and / or a cryogenic environment.

[0018] Exemplarily, each trapped quantum particle is trapped by a predetermined trapping potential. The trapping potential can be static or dynamic. For trapped quantum particles represented by energy levels in atoms or molecules, ions are trapped by electromagnetic fields. Exemplarily, ions are trapped by dynamic electric fields, particularly radio frequency fields. For trapped quantum particles represented by electron spin, electrons are trapped in potential wells within semiconductor systems.

[0019] According to at least one embodiment of the quantum computing configuration, the permanent magnet configuration includes a soft magnetic material surrounded by the permanent magnet configuration that is configured to enhance the magnetic field established by the permanent magnet configuration, for example, the soft magnetic material is disposed on a first axis, i.e., overlaps with the first axis in some regions.

[0020] For example, the soft magnetic material has a coercive force of up to 1000 A / m. Such soft magnetic materials are configured to be particularly well magnetized in a magnetic field, resulting in magnetic polarization of the soft magnetic material. The magnetic polarization of the soft magnetic material is achieved by the magnetic field of the permanent magnet arrangement. The magnetic polarization of the soft magnetic material provides a magnetic field component in the region of the soft magnetic material that is greater than the component of the magnetic field of the permanent magnet arrangement itself in the region of the soft magnetic material. Therefore, the soft magnetic material enhances the magnetic field of the permanent magnet arrangement, especially in the region of the soft magnetic material. This means that the magnetic field gradient along the first axis is also enhanced.

[0021] For example, the soft magnetic material is located in a vacuum environment and / or a cryogenic environment.

[0022] In particular, the idea is to use a permanent magnet configuration in combination with a soft magnetic material surrounded by the permanent magnet configuration. Different magnitudes of the magnetic field, i.e., the magnetic field gradient of the permanent magnet configuration, make the equilibrium position of the trapped quantum particle state-dependent. Also, due to the magnetic field gradient, the resonant frequency is unique for each trapped quantum particle.

[0023] The coupling of at least two trapped quantum particles depends on the magnitude of the magnetic field, i.e., the magnetic field gradient. Because the coupling is proportional to the square of the magnetic field gradient, the magnetic field gradient must be large enough to create sufficient coupling for fast computation, which can be achieved by the permanent magnet configuration described herein, particularly in combination with a soft magnetic material, i.e., a soft magnetic material structure. That is, the magnetic field gradient must be large enough to create a large coupling compared to the decoherence rate. In particular, the soft magnetic material enhances the magnetic field of the permanent magnet configuration in the region of the soft magnetic material, thus enhancing the magnetic field gradient compared to using the permanent magnet configuration alone.

[0024] In particular, the use of soft magnetic materials advantageously increases the magnetic field magnitude difference along the first axis by a factor of about 10 compared to the use of a permanent magnet arrangement alone, and therefore the magnetic field gradient along the first axis is also increased by a factor of about 10 compared to the permanent magnet arrangement.

[0025] Such relatively large magnetic field gradients improve addressing, provide lower crosstalk and stronger coupling of trapped quantum particles compared to the use of permanent magnet configurations alone, and therefore faster quantum operations are achievable and require fewer error correction operations.

[0026] Advantageously, combining a permanent magnet configuration with a soft magnetic material provides particularly high magnetic gradients while limiting the available solid angle and distance of the trapped quantum particles relative to the space. Therefore, such quantum computing configurations can be implemented in a variety of systems. That is, the permanent magnet configuration can be relatively far from the space, and the soft magnetic material can be relatively close to the space to provide relatively strong magnetic field gradients.

[0027] In essence, a permanent magnet arrangement is used that includes a soft magnetic material, which can act as a yoke structure to obtain large magnetic field gradients experienced by charged trapped quantum particles, creating significantly different magnetic fields seen by individual trapped quantum particles. In a quantum information environment, this allows for advanced addressing in frequency space, thus enabling individual single-qubit rotation with low crosstalk, as well as introducing coupling between charged trapped quantum particles to enable interactions, thus enabling multi-qubit gates. This can also be used in conjunction with radio-frequency (RF) fields for qubit control, where addressing by focusing radiation is not an option due to long wavelengths, and RF fields can offer advantages in terms of miniaturization and integration. To this end, large or steep magnetic field gradients are desirable, enabling better addressing with higher fidelity and faster quantum gates. Permanent magnet configurations, particularly Halbach arrays, allow for large magnetic field gradients, even when the distance between the segments of the permanent magnet configuration and the trapped quantum particles is limited by technological constraints. The yoke structure is positioned in a region where the magnetic field of the permanent magnet configuration is already of small magnitude, concentrating that magnetic field to a small cross-section of the yoke structure without exceeding the saturation magnetization of the yoke structure, thus substantially increasing the magnitude of the achievable magnetic field gradient, enabling lower crosstalk, stronger coupling, and faster quantum gates.

[0028] According to at least one embodiment of the quantum computing arrangement, the soft magnetic material is a ferromagnetic material configured to be magnetized by a magnetic field established by a permanent magnet arrangement.

[0029] According to at least one embodiment of the quantum computing configuration, the soft magnetic material has a melting point of greater than or equal to 500° C. The melting point is illustratively represented by the temperature at which the soft magnetic material changes its state.

[0030] For example, the melting point of the soft magnetic material is above 1000°C, about 1660°C.

[0031] According to at least one embodiment of the quantum computing configuration, the soft magnetic material has a primary direction of extension along a first axis. Illustratively, the soft magnetic material is elongated along the first axis. Such elongation advantageously enhances the magnitude of the magnetic field along the first axis, particularly in regions of the soft magnetic material.

[0032] According to at least one embodiment of the quantum computing configuration, the soft magnetic material has a relative permeability of 300 or more, in particular 1000 or more. The relative permeability is the permeability of the soft magnetic material divided by the permeability of free space.

[0033] Exemplarily, the relative permeability of the soft magnetic material is greater than or equal to 10,000 and less than or equal to 20,000, and in particular greater than or equal to 11,000 and less than or equal to 15,000. For example, the relative permeability of the soft magnetic material is about 12,000.

[0034] According to at least one embodiment of the quantum computing configuration, the soft magnetic material has a saturation flux density of greater than or equal to 1 T. Illustratively, the saturation flux density of the soft magnetic material is greater than or equal to 1.5 T and less than or equal to 5 T, and more particularly, greater than or equal to 2 T and less than or equal to 3 T. For example, the saturation flux density of the soft magnetic material is approximately 2.4 T.

[0035] According to at least one embodiment of the quantum computing configuration, the soft magnetic material includes iron, cobalt, and vanadium. For example, the soft magnetic material further includes at least one of the following materials: manganese, niobium, silicon, and carbon.

[0036] According to at least one embodiment of the quantum computing configuration, the concentration of iron and cobalt is greater than the concentration of vanadium. For example, the concentration of iron and cobalt is greater than or equal to 97% for the soft magnetic material. The concentration of vanadium is greater than or equal to 1.5% for the soft magnetic material.

[0037] According to at least one embodiment of the quantum computing configuration, the change in magnitude of the magnetic field along the first axis is 50 T / m or more. Illustratively, the change in magnitude of the magnetic field along the first axis in the region of the soft magnetic material is 100 T / m or more and 500 T / m or less, and in particular 200 T / m or more and 300 T / m or less.

[0038] According to at least one embodiment of the quantum computing configuration, the permanent magnet configuration has a plurality of segments, i.e., at least four segments. For example, the permanent magnet configuration includes at least four segments, particularly at least eight segments, at least 16 segments, or at least 32 segments. Each segment has a permanent magnet material. In particular, each of the segments has the same permanent magnet material. Illustratively, the permanent magnet material comprises a ferromagnetic material.

[0039] Each segment may be formed, for example, from one piece, or may be formed from at least two sub-segments, the at least two sub-segments having the same material and / or magnetic properties.

[0040] In a preferred embodiment, the first axis extends in a straight line from one of the segments to another one of the segments that is located diametrically opposite said one of the segments relative to the center of the permanent magnet arrangement.

[0041] According to at least one embodiment of the quantum computing configuration, each segment has a magnetization direction. The magnetization of each segment is determined 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, determines the respective magnetization direction. The dipole moment primarily refers to the magnetization direction.

[0042] According to at least one embodiment of the quantum computing configuration, the magnetization directions of the segments located in opposite regions are oriented in opposite directions, the segments being located in opposite regions with respect to the center of the permanent magnet configuration, and the magnetization directions of the segments located in the opposite regions are opposite to each other.

[0043] If there are m segments, where m is an even natural number greater than or equal to 4, the magnetization directions of two immediately adjacent segments are rotated by 360°·3 / m with respect to each other.

[0044] In particular, a first axis is defined for two segments arranged opposite each other, and the magnetization direction of each of the two segments is parallel to the first axis.

[0045] Illustratively, the permanent magnet configuration is a Halbach array.

[0046] According to at least one embodiment of the quantum computing configuration, the segments surround the space in the form of a ring, or alternatively, the segments surround the space in the form of a polygonal contour. This ring or polygonal contour is of an imaginary nature. Exemplarily, in a cross-sectional view along the main extension plane, each segment is located on a point, which is located on the ring or polygonal contour. The points are spaced apart from one another so that the sections do not overlap each other in the main extension plane. For example, each point represents the center of the respective segment.

[0047] According to at least one embodiment of the quantum computing configuration, the remanence of each of the segments is greater than or equal to 0.1 T and less than or equal to 1.5 T. In particular, the remanence of each of the segments is greater than or equal to 0.5 T and / or less than or equal to 1 T.

[0048] When the segments are arranged in the form of a ring, the magnetic flux density (vector B) corresponding to the magnetic field is:

number

[0049] For example, the edges of the segments that are arranged facing each other in opposite regions have a minimum distance from each other of 0.001 cm or more and 100 cm or less. In particular, this minimum distance is 0.01 cm or more or 1 cm or more and 25 cm or less or 50 cm or less. In this context, opposite sides means, for example, opposite sides with respect to the center of gravity of the permanent magnet arrangement and / or with respect to the center of the magnetic field, i.e., the center of the quadrupole field.

[0050] For example, this minimum distance divided by two defines the inner radius of the permanent magnet configuration.

[0051] For example, each segment has an extension along the corresponding minimum distance of 0.001 cm or more and 100 cm or less, in particular, this extension is 0.01 cm or more or 1 cm or more and 25 cm or less or 50 cm or less.

[0052] For example, the minimum distance divided by two and the extension along the corresponding minimum distance is defined as the outer radius of the permanent magnet arrangement.

[0053] According to at least one embodiment of the quantum computing configuration, the soft magnetic material has a first portion and a second portion. The first portion and the second portion are spaced apart from each other along a first axis. Illustratively, both the first portion and the second portion overlap with the first axis in some areas. Furthermore, both the first portion and the second portion have a primary extension direction along the first axis.

[0054] Illustratively, the distance along the first axis from the first portion to the second portion is 1 μm or more and 25 cm or less, in particular 50 μm or more and 5 cm or less.

[0055] According to at least one embodiment of the quantum computing configuration, the first portion and the second portion form a yoke structure within a permanent magnet configuration. For example, the first portion is formed as one pole of the yoke structure and the second portion is formed as another pole of the yoke structure. In particular, the magnetic configuration of the yoke structure is induced by the magnetic field of the permanent magnet configuration.

[0056] For example, the first and second parts each have an end face extending substantially perpendicular to the first axis, with the space between them. "Substantially perpendicular" means that the end faces may have an angle of ±1° with respect to the direction perpendicular to the first axis due to manufacturing tolerances. In other words, the end faces of the first and second parts are positioned on opposite sides of the space.

[0057] Typically, the magnetic field lines emerge from the soft magnetic material perpendicular to the end faces. Illustratively, the end faces each have a distance to the center of the permanent magnet arrangement. The distances of the first and second parts, particularly the end faces, to the center are substantially equal to each other. "Substantially equal" means that the distances from the end faces to the center can differ from each other by at most 50 μm, particularly at most 10 μm.

[0058] Therefore, because the end faces extend perpendicular to the first axis and are equal in distance to each other, the magnetic field lines of the first and second parts advantageously meet at the center of the permanent magnet configuration, which also contributes to an increase in the difference in the magnitude of the magnetic fields along the first axis, i.e., an increase in the magnetic field gradient.

[0059] According to at least one embodiment, the quantum computing configuration further comprises an ion trap having a first endcap electrode and a second endcap electrode with the space therebetween.

[0060] According to at least one embodiment of the quantum computing configuration, the first portion is formed as a first end cap electrode and the second portion is formed as a second end cap electrode. The first end cap electrode and the second end cap electrode are each configured to be supplied with direct current, or dc for short. The first end cap electrode and the second end cap electrode are configured to trap a quantum particle to be trapped along a first axis between the first end cap electrode and the second end cap electrode.

[0061] For example, the first and second end cap electrodes comprise a metal coating that is electrically conductive, for example, the metal coating of the first and second end cap electrodes comprises or consists of gold.

[0062] According to at least one embodiment, the quantum computing configuration further comprises an ion trap for hosting the volume having at least one substrate.

[0063] According to at least one embodiment of the quantum computing configuration, the at least one substrate is formed to be electrically insulating, and the first and second portions are embedded in the at least one substrate. The electrically insulating substrate is formed from or consists of an electrically insulating material. "Embedded" here means that at least one outer surface of the first and second portions is covered by the substrate. Illustratively, all outer surfaces of the first and second portions are covered by the substrate.

[0064] According to at least one embodiment, the quantum computing arrangement further comprises at least one additional permanent magnet arrangement. In particular, the quantum computing arrangement can comprise several additional permanent magnet arrangements. The additional permanent magnet arrangements can have the same dimensions and / or characteristics as the permanent magnet arrangements described herein above.

[0065] According to at least one embodiment, the quantum computing arrangement further comprises at least one additional soft magnetic material surrounded by the at least one additional permanent magnet arrangement, which can have the same shape and properties as the soft magnetic material described herein above.

[0066] According to at least one embodiment of the quantum computing configuration, the permanent magnet configuration has a rotated position relative to the additional permanent magnet configuration. For example, the additional permanent magnet configuration is arranged in a rotated configuration, in particular an out-of-plane rotated configuration, relative to the permanent magnet configuration so that an angle is enclosed by the respective main extension planes. This means that the additional main extension planes of the additional permanent magnet configurations are rotated out of the plane of the main extension planes of the permanent magnet configurations. Exemplarily, this angle can be between 0° and 180°, in particular 60°, 120° and / or 90°.

[0067] For example, the additional permanent magnet configurations are rotated 90° relative to the permanent magnet configurations so that their respective main extension planes subtend an angle of 90°.

[0068] According to at least one embodiment of the quantum computing arrangement, the permanent magnet arrangement and the additional permanent magnet arrangement are parallel to each other.

[0069] Illustratively, the first axis and the additional first axis are positioned parallel to each other.

[0070] Alternatively, the additional permanent magnet arrangement may be arranged in a rotated configuration, in particular an in-plane rotated configuration, relative to the permanent magnet arrangement. In this case, the main extension plane and the additional main extension plane are parallel to each other. In the case of such an in-plane rotation, an angle is enclosed by the respective first axes, i.e., the first axis and the additional first axis. Exemplarily, this angle may be between 0° and 90°.

[0071] For example, the additional permanent magnet configuration is rotated in-plane by 90° relative to the permanent magnet configuration, such that each first axis subtends a 90° angle. In this embodiment, the first axis and the additional first axis are positioned perpendicular to each other.

[0072] Such configurations, comprising a permanent magnet configuration and an additional permanent magnet configuration, illustratively each form a three-dimensional confined space, for example a three-dimensional gradient space, with respect to the magnetic field.

[0073] For example, an additional soft magnetic material is disposed along an additional first axis of the additional permanent magnet arrangement.

[0074] Furthermore, quantum computers having the quantum computing configurations described above are defined herein, i.e., features relating to quantum computers are also applicable to quantum computing configurations and vice versa.

[0075] The quantum computer is configured to perform quantum computing processes by using a quantum computing arrangement, the trapped quantum particles of which can be particularly well controlled and manipulated using the permanent magnet arrangement described herein above, to perform a given quantum computing task. [Brief explanation of the drawings]

[0076] The quantum computing configuration is described in more detail below with reference to exemplary embodiments and associated figures. [Figure 1] 1 and 2 each show a cross-sectional view of a quantum computing configuration in accordance with an example embodiment. [Figure 2] 1 and 2 each show a cross-sectional view of a quantum computing configuration according to an example embodiment. [Figure 3] 1 shows an example diagram of magnetic field magnitudes of a permanent magnet configuration of a quantum computing configuration in accordance with an illustrative embodiment. [Figure 4]1 illustrates a quantum computer in accordance with an illustrative embodiment.

[0077] In the drawings, elements that are the same, similar, or have the same effect are provided with the same reference signs. The drawings and the proportions of the elements shown should not be considered to be true to scale. Rather, individual elements may be shown exaggeratedly large for better representation and / or better understandability. DETAILED DESCRIPTION OF THE INVENTION

[0078] The quantum computing configuration 1 according to the exemplary embodiment of Figure 1 includes a permanent magnet configuration 2. The permanent magnet configuration 2 includes 16 segments 3. The segments 3 surround a space 5 of the quantum computing configuration 1 where trapped quantum particles 6 are trapped during operation of the quantum computing configuration 1. The segments 3 surround the space 5 in the form of a ring. Each segment 3 is positioned with its center at a point on the ring.

[0079] The permanent magnet arrangement 2 has a main extension plane extending along the x-axis and y-axis shown in FIG. 1. Each segment 3 has a cross-sectional shape of an annular sector or a circular ring sector, and all segments 3 share the same common inner ring and the same common outer ring. The width of each segment 3 gradually decreases towards the space 5, i.e., the opposite edges of each segment 3 facing the space 5 are curved. The normal flux of the curved edges points away from the space 5. In other words, the radius of the curved edges is defined relative to the central region of the permanent magnet arrangement 2.

[0080] The curved edges of the segments 3 facing each other and located in the opposite region to the central region have a minimum distance of about 10 cm from each other. The minimum distance divided by 2 is the inner radius R of the permanent magnet arrangement 2. i Define

[0081] Also, each segment 3 has an extension along a corresponding minimum distance that is about 20 cm. The minimum distance divided by 2 and the extension along the corresponding minimum distance are the outer radius R of the permanent magnet arrangement 2. o Define

[0082] For example, directly adjacent segments 3 are spaced apart from one another: the mutually facing edges of directly adjacent segments 3 have a distance of about 1 mm from one another.

[0083] In this exemplary embodiment, each segment 3 has a line of symmetry that bisects both edges facing the space 5. This line of symmetry is identical for segments 3 arranged opposite each other. One of these lines of symmetry represents a first axis 7 of the permanent magnet arrangement 2, which exemplarily extends in the main extension plane.

[0084] Each segment 3 also has a magnetization direction 4, depicted in Figure 1 as an arrow within the segment 3. The magnetization directions 4 of segments 3 located in opposite regions with respect to the center of the permanent magnet configuration 2 are oriented in opposite directions. A first axis 7 of the permanent magnet configuration 2 is defined for two segments 3 located opposite each other, and the magnetization directions 4 of each of the two segments 3 are parallel to the first axis 7.

[0085] Each magnetization direction 4 subtends an angle with the first axis 7. These angles are all formed differently, for example the angles of directly adjacent segments 3 differ from each other by 67.5°.

[0086] In the exemplary embodiment of Figures 1 and 2, the first axis 7 points in the direction of the x-axis.

[0087] Also, 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°.

[0088] When moving clockwise around the ring from a segment 3 having a magnetization direction 4 that is parallel to and points in the same direction as the first axis 7 back to this segment 3, the magnetization direction 4 also rotates clockwise.

[0089] Using such segments 3, the permanent magnet arrangement 2 is configured to generate a quadrupole magnetic field, thus having a different magnitude along the first axis 7, i.e., a magnetic field gradient along the first axis 7. Also, during operation of the quantum computing arrangement 1, the trapped quantum particles 6 are arranged linearly next to each other along the first axis 7.

[0090] The magnitude of the magnetic field acting on the trapped quantum particles 6 varies for each trapped quantum particle 6 arranged on the first axis 7 .

[0091] Furthermore, the permanent magnet arrangement 2 comprises a soft magnetic material 60 arranged on a first axis 7. The soft magnetic material 60 has a first portion 62 and a second portion 63 spaced apart from each other along the first axis 7. Furthermore, both the first portion 62 and the second portion 63 have a main direction of extension along the first axis 7.

[0092] Illustratively, first portion 62 is first endcap electrode 41 of ion trap 100, and second portion 63 is second endcap electrode 42 of ion trap 100. In this case, first endcap electrode 41 and second endcap electrode 42 form yoke structure 60.

[0093] The center of the permanent magnet arrangement 2 is located between the first portion 62 and the second portion 63. In other words, the space 5 is located between the first portion 62 and the second portion 63.

[0094] The magnetic field of the permanent magnet arrangement 2, in particular the magnitude of the magnetic field, is increased by a factor of about ten in the region of the first portion 62 and in the region of the second portion 63, while the magnitude of the magnetic field is zero in the center of the permanent magnet arrangement 2. That is to say, the difference in the magnitude of the magnetic field is increased along the first axis 7 from the first portion 62 to the center and from the second portion 63 to the center.

[0095] Advantageously, with such a quantum computing configuration 1 particularly strong magnetic field gradients are achieved.

[0096] Illustratively, the trapped quantum particle 6 is a trapped ion.

[0097] For example, the inner radius R according to this exemplary embodiment i is approximately 5 cm, and the outer radius R o is about 25 cm. The residual magnetism B of each of the segments 3 R is, for example, 1 T. Therefore, the magnetic field, and in particular the corresponding magnetic flux density (vector B), is:

number

[0098] The origin of the coordinates x and y is located in the centre of the permanent magnet arrangement 2 .

[0099] Also, the distance d between directly adjacent trapped ions is approximately 3 μm. Therefore, the magnetic flux density (vector B) can be calculated for each position of the trapped ion. As a result, the difference for a particular transition between adjacent trapped ions can also be determined.

[0100] Exemplarily, σ between directly adjacent trapped ions ± The frequency difference between the transitions is greater than or equal to 10 kHz and less than or equal to 100 MHz. ± The transition can be excited by left- or right-handed circularly polarized electromagnetic waves with polarization perpendicular to the local magnetic field.

[0101] For example, the frequency difference of π transitions between immediately adjacent trapped ions is greater than or equal to 1 kHz and less than or equal to 10 MHz. Such π transitions are excited by linearly polarized electromagnetic waves with polarization parallel to the local magnetic field.

[0102] In contrast to the exemplary embodiment of FIG. 1, the quantum computing arrangement 1 according to the exemplary embodiment of FIG. 2 has a permanent magnet arrangement 2 having segments 3 each having a squared configuration.

[0103] Each segment 3 has a square cross-sectional shape. The magnetization direction 4 relative to the edges of the square is the same for each segment 3. Directly adjacent segments 3 are rotated relative to each other so that the magnetization direction 4 of each segment 3 coincides with an angle according to FIG.

[0104] In FIG. 3, the position x in mm is plotted on the horizontal axis and the corresponding magnetic field magnitude, expressed by the absolute value of the magnetic field |B| in T, is plotted on the vertical axis.

[0105] The horizontal axis of the diagram shown in Figure 3 corresponds to the x-axis according to Figures 1 and 2. The position x equal to 0 corresponds to the centre of the permanent magnet arrangement 2 according to Figures 1 and 2.

[0106] The absolute value of the magnetic flux density |B|, i.e., the magnitude of the magnetic field, is symmetrical with respect to the center of the permanent magnet configuration 2. At negative position values ​​x, the absolute value of the magnetic flux density |B|, i.e., the magnitude of the magnetic field, has a negative gradient, and at positive position values ​​x, it has a positive gradient.

[0107] In a region of ±250 μm around the center of the permanent magnet configuration 2, the difference in magnetic field magnitude is approximately linear. This results in a magnetic field gradient of approximately 200 T / m. The first and second portions 62, 63 of the soft magnetic material 60 begin approximately at x-positions of approximately −2 mm and approximately 2 mm. That is, the distance between the first and second portions 62, 63 along the first axis 7 is approximately 4 mm.

[0108] Quantum computer 8 according to the exemplary embodiment of Figure 4 comprises quantum computing arrangement 1 according to one of the exemplary embodiments of Figures 1 or 2 and quantum computing device 9 disposed within chamber 10. Quantum computing device 9 is connected to components external to quantum computer 8 through chamber 10 by a number of connections 11. For example, connections 11 connect quantum computing device 9 to external electronics 12 and classical computer 13.

[0109] For example, quantum computing device 9 is configured to trap, manipulate, and measure trapped quantum particles 6, each representing a qubit, within space 5 during operation. To this end, quantum computing device 9 may have internal electronics including electrodes, light guides, and / or electronic devices. The electronic devices may include circuits, integrated electronics, and / or detectors, such as photon detectors and / or charge detectors, and controllers. Illustratively, the internal electronics are provided for preprocessing. For example, these components enable measurement of the respective states of the qubits and enable gate operations on the qubits. Thus, quantum computing device 9 is configured to trap trapped quantum particles 6 and perform operations and measurements on the trapped quantum particles 6.

[0110] The quantum computing device 9 is mounted in a chamber 10, which may be an ultra-high vacuum chamber, an extremely high vacuum chamber, and / or a cryostat. If the chamber 10 is an ultra-high vacuum chamber or an extremely high vacuum chamber, the permanent magnet arrangement 2 may be located outside the chamber 10. In this case, the permanent magnet arrangement 2 surrounds the chamber 10. Alternatively, the permanent magnet arrangement 2 may be located within the ultra-high vacuum chamber or the extremely high vacuum chamber or the cryostat.

[0111] Illustratively, if the chamber 10 is a cryostat, the permanent magnet arrangement 2 is located inside the chamber 10 (not shown here). It is also contemplated that if the chamber 10 is a cryostat, the permanent magnet arrangement 2 may also be located outside the chamber 10 (not shown here).

[0112] Quantum computing device 9 is connected via connection 11 to external electronics 12, which may be located at least partially inside chamber 10 and partially outside chamber 10. External electronics 12 is also connected to a classical computer 13.

[0113] Illustratively, the external electronics 12 includes an analog-to-digital converter and a signal generator, such as a radio frequency generator, a microwave signal generator, a low frequency signal generator, and / or a DC signal generator, etc. Furthermore, the external electronics 12 can include transistor-transistor logic TTL.

[0114] Additionally, the external electronics 12 may further include at least one laser system configured to cool the trapped ions, and the laser system may be configured to excite specific states of the trapped ions.

[0115] Classical computer 13 is configured, for example, to provide and receive digital signals that correspond to control signals used to operate on the qubits and measurement signals that correspond to the states of the qubits.

[0116] 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 qubits to quantum computing device 9. External electronics 12 is also configured to provide measured analog signals from quantum computing device 9 to classical computer 13, or to process such signals directly to cause any response signals to be generated by control electronics 12.

[0117] Classical computer 13 is illustratively configured with a particular algorithm, i.e., a predetermined quantum computation that solves a particular problem, and is configured to convert compiled code corresponding to the algorithm into commands for quantum computing device 9. The commands are then transmitted to quantum computing device 9 via external electronics 12. Classical computer 13 is also configured to receive measurement results of the particular algorithm.

[0118] 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.

[0119] The invention is not limited to these exemplary embodiments by the description thereof, but rather encompasses any novel feature as well as any combination of features, particularly including 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]

[0120] 1. Quantum Computing Configuration 2. Permanent magnet configuration 3 segments 4 Magnetization direction 5 Space 6 Trapped quantum particles 7 First Axis 8. Quantum Computers 9. Quantum Computing Devices 10 Chambers 11 Connection 12 External Electronics 13 Classical Computers 100 Ion Trap 40 End cap electrode 41 first end cap electrode 42 second end cap electrode 50 Base material 60 yoke structure 61 Soft magnetic materials 62 Part 1 63 Part 2 d distance R i inner radius R o outer radius

Claims

1. a permanent magnet arrangement configured to establish magnetic fields having different magnitudes for different positions on a first axis; a space for at least two trapped quantum particles disposed along the first axis; a soft magnetic material surrounded by the permanent magnet arrangement, the soft magnetic material configured to enhance the magnetic field established by the permanent magnet arrangement; A quantum computing configuration having:

2. 10. The quantum computing arrangement of claim 1, wherein the soft magnetic material is a ferromagnetic material configured to be magnetized by a magnetic field established by a permanent magnet arrangement.

3. 3. The quantum computing arrangement of claim 1 or 2, wherein the soft magnetic material has a melting point of 500°C or higher.

4. 4. The quantum computing arrangement of claim 1, wherein the soft magnetic material has a main direction of extension along the first axis.

5. the soft magnetic material has a relative permeability of 1000 or greater; and / or The soft magnetic material has a saturation magnetic flux density of 1 T or more.

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

6. the soft magnetic material includes iron, cobalt, and vanadium; The concentrations of iron and cobalt are greater than the concentration of vanadium, 6. A quantum computing arrangement according to any one of claims 1 to 5.

7. 7. The quantum computing arrangement of claim 1, wherein the change in magnitude of the magnetic field along the first axis is 50 T / m or greater.

8. the permanent magnet arrangement has a plurality of segments, the plurality of segments being at least four segments; Each segment has a magnetization direction.

8. A quantum computing arrangement according to any one of claims 1 to 7.

9. 10. The quantum computing configuration of claim 8, wherein the magnetization directions of segments located in opposite regions are oriented in opposite directions.

10. the plurality of segments surround the space in the form of a ring; or the plurality of segments encircling the space in the form of a polygonal outline; 10. A quantum computing arrangement according to claim 8 or 9.

11. 11. The quantum computing configuration of claim 1, wherein each of the plurality of segments has a remanence of 0.1 T or more and 1.5 T or less.

12. the soft magnetic material has a first portion and a second portion; the first portion and the second portion are spaced apart from each other along the first axis.

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

13. 13. The quantum computing arrangement of claim 1, wherein the first portion and the second portion form a yoke structure within the permanent magnet arrangement.

14. The quantum computing arrangement further comprises: an ion trap having a first end cap electrode and a second end cap electrode with the space therebetween; and the first portion is formed as the first end cap electrode; the second portion is formed as the second end cap electrode; 14. A quantum computing arrangement according to claim 12 or 13.

15. The quantum computing arrangement further comprises: an ion trap for hosting said volume, said ion trap having at least one substrate; and the at least one substrate is formed to be electrically insulating; the first portion and the second portion are embedded in the at least one substrate.

14. A quantum computing arrangement according to any one of claims 1 to 13.

16. at least one additional permanent magnet arrangement; at least one additional soft magnetic material surrounded by the at least one additional permanent magnet arrangement; and 16. The quantum computing arrangement of any one of claims 1 to 15, further comprising:

17. 17. A quantum computer comprising the quantum computing arrangement of any one of claims 1 to 16 configured to perform quantum computations.

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