Quantum computing device and quantum computer

Abstract

There is described a quantum computing device (1) comprising:-a permanent magnet device (2) configured to establish magnetic fields of different intensities from each other for different positions on a first shaft (7); a space (5) for at least two captured quantum particles (6) arranged along a first axis (7); and-a soft magnetic material (61) surrounded by the permanent magnet arrangement (2), the soft magnetic material (61) being configured to enhance the magnetic field established by the permanent magnet arrangement (2). The invention further relates to a quantum computer (8) comprising the quantum computing device (1).

Description

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

[0002] For many quantum computing processes using quantum computing devices, these devices can be configured to capture trapped quantum particles. The trapped quantum particles must be controlled and manipulated to perform calculations. For charged trapped quantum particles, interactions such as Coulomb repulsion produce coupling of adjacent trapped quantum particles and achieve entanglement. Therefore, in order to perform quantum computing processes using trapped quantum particles, the trapped quantum particles must be individually controllable and addressable relative to each other.

[0003] It is desirable to individually address multiple trapped quantum particles, such as qubit registers, with negligible crosstalk. However, crosstalk between adjacent trapped quantum particles is often a difficult-to-control error source in quantum computer processing and hinders meaningful application of quantum error correction protocols, thereby hindering scalability.

[0004] The object to be solved is therefore to specify a quantum computing device with improved controllability. Furthermore, a quantum computer comprising such a quantum computing device is specified.

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

[0006] According to at least one embodiment, a quantum computing device includes a permanent magnet device configured to establish a magnetic field having different strengths for different positions on a first axis. Exemplarily, the strength of the magnetic field varies along the first axis for different positions on the first axis. The strength is, for example, symmetric along the first axis relative to the center of the permanent magnet device. That is, for example, there are two points on the first axis with the same strength.

[0007] The permanent magnet arrangement has a main extension plane, wherein the first axis extends along the main extension plane. The first axis is a virtual axis. For example, the first axis is an axisymmetric axis within the main extension plane. That is, the first axis divides the permanent magnet arrangement into two halves along the main extension plane in a cross-sectional view, and the shapes of the two halves are substantially the same. "Substantially the same" exemplarily means that due to manufacturing tolerances of the permanent magnet arrangement, the areas of the halves, such as the cross-sections 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 magnetic multipole field. In particular, a magnetic quadrupole field is generated, wherein, in the center of the permanent magnet arrangement, the strength of the magnetic field vanishes, for example, about 0 T. Due to the magnetic multipole field, in particular, due to the quadrupole field, the strength of the magnetic field is different for different positions on the first axis.

[0009] For such a permanent magnet arrangement, the strength of the magnetic field varies continuously from the center along the first axis, ie for different positions on the first axis. Therefore, the strength of the magnetic field at different positions on the first axis is a representation of the magnetic field gradient along the first axis.

[0010] The magnetic field is represented by the magnetic flux density. In addition, the absolute value of the magnetic flux density corresponds to the strength of the magnetic field at a predetermined position on the first axis.

[0011] The components of the magnetic field correspond to the components of the vectors, wherein the vectors may point in any direction relative to the first axis. That is, at least some of the vectors of the magnetic field at different positions on the first axis may have different angles relative to the first axis. For example, at least some of the vectors of the magnetic field point in a radial direction of the first axis or in an axial direction of the first axis.

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

[0013] The distribution of the intensity of the magnetic field is symmetrical along the first axis relative to the center of the permanent magnet device. Exemplarily, the first axis is divided into two halves by the center of the permanent magnet device. The intensity of the magnetic field has a negative slope for one half axis and a positive slope for the other half axis. Relative to the intensity of the magnetic field along the first axis, the magnetic field gradient increases, for example, approximately linearly along the first axis. Due to production tolerances of the permanent magnet device, for example in the center region, there may be a deviation of up to 5% from linearity. That is, the magnetic field gradient is approximately constant along the first axis starting from the center.

[0014] According to at least one embodiment, the quantum computing device includes a space for at least two trapped quantum particles arranged along a first axis. That is, in operation of the quantum computing device, the at least two trapped quantum particles are arranged along the first axis. Exemplarily, the space has a main extension direction extending along the first axis.

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

[0016] Trapped quantum particles are represented, for example, by energy levels in atoms or molecules, spins of electrons and / or nuclei, charges, fluxes or phases in superconductors, or 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 trap potential. The trap 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 the spin of electrons, electrons are trapped in a potential well within a semiconductor system.

[0019] According to at least one embodiment of the quantum computing device, the permanent magnet device includes a soft magnetic material surrounded by the permanent magnet device, and the soft magnetic material is configured to enhance the magnetic field established by the permanent magnet device. For example, the soft magnetic material is arranged on the first axis, that is, overlaps with the first axis in some areas.

[0020] For example, the soft magnetic material has a coercivity of at most 1000 A / m. Such a soft magnetic material is configured to be particularly well magnetized in a magnetic field, thereby causing 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 device. The magnetic polarization of the soft magnetic material provides a magnetic field component of the magnetic field in the region of the soft magnetic material, which is greater than the component of the magnetic field of the permanent magnet device itself in the region of the soft magnetic material. Therefore, the soft magnetic material enhances the magnetic field of the permanent magnet device, in particular its magnetic field in the region of the soft magnetic material. That is to say, 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, one idea is to use a permanent magnet device in combination with a soft magnetic material surrounded by the permanent magnet device. The different magnetic field strengths of the permanent magnet device, i.e. the magnetic field gradient, make the equilibrium position of the trapped quantum particles state-dependent. In addition, 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 strength of the magnetic field, that is, the magnetic field gradient. Since the coupling is proportional to the square of the magnetic field gradient, the magnetic field gradient must be large enough to produce sufficient coupling for fast calculations, which can be achieved by combining the permanent magnet device described in this article with soft magnetic materials (particularly the structure of soft magnetic materials). In other words, the magnetic field gradient must be large enough to produce a coupling that is larger than the decoherence rate. In particular, compared with the use of a permanent magnet device alone, the soft magnetic material enhances the magnetic field of the permanent magnet device in the soft magnetic material region, and thus enhances the magnetic field gradient.

[0024] In particular, due to the use of soft magnetic material, the difference in strength of the magnetic field along the first axis is advantageously increased by a factor of about 10 compared to using a permanent magnet arrangement alone. Thus, the magnetic field gradient along the first axis is also increased by a factor of about 10 compared to a permanent magnet arrangement.

[0025] Such relatively large magnetic field gradients improve addressing and provide lower crosstalk and stronger coupling of trapped quantum particles compared to permanent magnet devices alone. As a result, faster quantum operations can be achieved and fewer error correction operations are required.

[0026] Advantageously, using a permanent magnet arrangement in combination with a soft magnetic material, the magnetic gradient is particularly high, while the available solid angle and distance relative to the space of the trapped quantum particle is limited. Thus, such a quantum computing device can be implemented in a variety of systems. That is, the permanent magnet arrangement can be relatively far away from the space, wherein the soft magnetic material can be relatively close to the space, thereby providing a relatively strong magnetic field gradient.

[0027] In summary, a permanent magnet device containing a soft magnetic material (which may be a yoke structure) is used to obtain a large magnetic field gradient experienced by a charged trapped quantum particle to produce a largely different magnetic field experienced by each trapped quantum particle. In a quantum information environment, this enables improved addressing in frequency space, and therefore enables individual single-qubit rotations with low crosstalk, and introduces coupling between charged trapped quantum particles to enable interaction, thereby realizing a multi-qubit gate. This can also be used in conjunction with a radio frequency (RF) field for qubit control, for which addressing by focused radiation is not an option due to the longer wavelength, but the RF field may be more advantageous in terms of miniaturization and integration. To this end, a large or steep magnetic field gradient is required to enable better addressing and faster quantum gates with higher fidelity, and a permanent magnet device, especially a Halbach device, is able to achieve a large magnetic field gradient, even when the distance between the segment of the permanent magnet device and the trapped quantum particle is limited to a lower limit by technical constraints. The yoke structure is placed in an area where the magnetic field of the permanent magnet device already has a small strength and is concentrated to a small cross-section of the yoke structure without exceeding the saturation magnetization of the yoke structure, thereby significantly increasing the size of the achievable magnetic field gradient, thereby achieving lower crosstalk, stronger coupling and faster quantum gates.

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

[0029] According to at least one embodiment of the quantum computing device, the soft magnetic material has a melting temperature of at least 500° C. The melting temperature is exemplarily represented by the temperature at which the soft magnetic material changes its state.

[0030] Exemplarily, the melting temperature of the soft magnetic material is at least 1000°C, and approximately 1660°C.

[0031] According to at least one embodiment of the quantum computing device, the soft magnetic material has a main extension direction along the first axis. Exemplarily, the soft magnetic material is elongated in the direction of the first axis. Due to such elongation, the strength of the magnetic field is advantageously enhanced along the first axis, in particular in the region of the soft magnetic material.

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

[0033] Exemplarily, the relative magnetic permeability of the soft magnetic material is at least 10000 and at most 20000, in particular at least 11000 and at most 15000. For example, the relative magnetic permeability of the soft magnetic material is approximately 12000.

[0034] According to at least one embodiment of the quantum computing device, the soft magnetic material has a saturation flux density of at least 1 T. Exemplarily, the saturation flux density of the soft magnetic material is at least 1.5 T and at most 5 T, in particular at least 2 T and at most 3 T. For example, the saturation flux density of the soft magnetic material is about 2.4 T.

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

[0036] According to at least one embodiment of the quantum computing device, the content of iron and cobalt is greater than the content of vanadium. For example, the content of iron and cobalt is at least 97% relative to the soft magnetic material. The content of vanadium is at least 1.5% relative to the soft magnetic material.

[0037] According to at least one embodiment of the quantum computing device, the intensity of the magnetic field varies along the first axis by at least 50 T / m. Exemplarily, the intensity of the magnetic field varies along the first axis in the region of the soft magnetic material by at least 100 T / m and at most 500 T / m, in particular at least 200 T / m and at most 300 T / m.

[0038] According to at least one embodiment of the quantum computing device, the permanent magnet device comprises a plurality of segments, i.e. at least four segments. For example, the permanent magnet device comprises at least four segments, in particular at least 8 segments, at least 16 segments or at least 32 segments. Each segment comprises a permanent magnetic material. In particular, each segment comprises the same permanent magnetic material. Exemplarily, the permanent magnetic material comprises a ferromagnetic material.

[0039] Each segment is, for example, formed in one piece. Alternatively, each segment is formed from at least two sub-segments, wherein at least two sub-segments have the same material and / or magnetization properties.

[0040] In a preferred embodiment, the first axis extends linearly from one of the segments to another of the segments, the other segment being positioned opposite one of the segments relative to the centre of the permanent magnet arrangement.

[0041] According to at least one embodiment of the quantum computing device, each segment has a magnetization direction. The magnetization of each segment is defined by a vector field representing the dipole moment of the corresponding permanent magnetic material. In other words, the corresponding permanent magnetic material exhibits a dipole moment. The vector field, in particular the dipole moment of the permanent magnetic material, defines the corresponding magnetization direction. The dipole moment mainly points in the magnetization direction.

[0042] According to at least one embodiment of the quantum computing device, the magnetization directions of the segments arranged in the opposite regions point in opposite directions. The segments are arranged at the opposite regions relative to the center of the permanent magnet device. The magnetization directions of the segments arranged at the opposite regions are opposite to each other.

[0043] If there are m segments, where m is an even natural number of at least 4, the magnetization directions of two directly adjacent segments are rotated by 360°·3 / m relative to each other.

[0044] In particular, a first axis is defined with respect to two segments arranged opposite one another, wherein the magnetization directions of the respective two segments are parallel to the first axis.

[0045] Exemplarily, the permanent magnet arrangement is a Halbach arrangement.

[0046] According to at least one embodiment of the quantum computing device, the segment surrounds the space in the form of a ring, or the segment surrounds the space in the form of a polygonal outline. The outline of the ring or polygon has a virtual nature. Exemplarily, in a cross-sectional view along the main extension plane, each segment is arranged on a point, wherein the point is located on the outline of the ring or polygon. These points are spaced apart from each other so that these parts do not overlap with each other in the main extension plane. For example, each point represents the center of the corresponding segment.

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

[0048] If the segments are arranged in the form of a ring, the magnetic flux density corresponding to the magnetic field Has the following form:

[0049]

[0050] Among them, B R is the remanence of the segment, R i is the inner radius, R o is the outer radius and x and y are coordinates within the permanent magnet arrangement. Advantageously, in the region of the soft magnetic material, in particular along the first axis, the resulting magnetic field is further enhanced by the soft magnetic material.

[0051] For example, the edges of the segments arranged in opposite areas and facing each other have a minimum distance of at least 0.001 cm and at most 100 cm relative to each other. In particular, the minimum distance is at least 0.01 cm or at least 1 cm and at most 25 cm or at most 50 cm. In this context, relative means, for example, relative to the center of gravity of the permanent magnet arrangement and / or relative to the center of the magnetic field, i.e., the center of the quadrupole field.

[0052] For example, the minimum distance divided by 2 is defined as the inner radius of the permanent magnet arrangement.

[0053] For example, each segment has a range of at least 0.001 cm and at most 100 cm along the corresponding minimum distance. In particular, the range is at least 0.01 cm or at least 1 cm and at most 25 cm or at most 50 cm.

[0054] For example, the minimum distance divided by 2 and the range along the corresponding minimum distance is defined as the outer radius of the permanent magnet device.

[0055] According to at least one embodiment of the quantum computing device, 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. Exemplarily, both the first portion and the second portion overlap with the first axis in some regions. In addition, both the first portion and the second portion have a main extension direction along the first axis.

[0056] Exemplarily, the distance from the first portion to the second portion along the first axis is at least 1 μm and at most 25 cm, in particular at least 50 μm and at most 5 cm.

[0057] According to at least one embodiment of the quantum computing device, the first part and the second part form a yoke structure within the permanent magnet device. For example, the first part forms one pole of the yoke structure, and the second part forms another pole of the yoke structure. In particular, the magnetic structure of the yoke structure is induced by the magnetic field of the permanent magnet device.

[0058] For example, the first part and the second part each have an end face extending substantially perpendicular to the first axis, and the space is located between the end faces. Substantially perpendicular means that due to production tolerances, the end face may have an angle of ±1° with the direction perpendicular to the first axis. That is, the end face of the first part and the end face of the second part are arranged opposite to each other with respect to the space.

[0059] Typically, the magnetic field lines leave the soft magnetic material perpendicular to the end faces. Exemplarily, the end faces each have a distance to the center of the permanent magnet arrangement. The distances from the first portion and the second portion, in particular 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 may deviate from each other by at most 50 μm, in particular by at most 10 μm.

[0060] Therefore, since the end faces extend perpendicularly to the first axis and the distances are equal to each other, the magnetic field lines of the first and second parts advantageously meet in the center of the permanent magnet arrangement, which also helps to increase the difference in magnetic field strength along the first axis, ie the magnetic field gradient.

[0061] According to at least one embodiment, the quantum computing device further includes an ion trap, which includes a first end cap electrode and a second end cap electrode, and the space is located between the first end cap electrode and the second end cap electrode.

[0062] According to at least one embodiment of the quantum computing device, 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 (DC for short). The first end cap electrode and the second end cap electrode are configured to capture quantum particles to be captured along a first axis, between the first end cap electrode and the second end cap electrode.

[0063] For example, the first end cap electrode and the second end cap electrode are provided with a conductive metal coating. For example, the metal coating of the first end cap electrode and the second end cap electrode comprises gold or consists of gold.

[0064] According to at least one embodiment, the quantum computing device further includes an ion trap, which is used to contain a space and includes at least one substrate.

[0065] According to at least one embodiment of the quantum computing device, at least one substrate is formed to be electrically insulating, and the first part and the second part are embedded in the at least one substrate. The electrically insulating substrate is formed of or consists of an electrically insulating material. Here, "embedded" means that at least one outer surface of the first part and the second part is covered by the substrate. Exemplarily, all outer surfaces of the first part and the second part are covered by the substrate.

[0066] According to at least one embodiment, the quantum computing device further comprises at least one additional permanent magnet device. In particular, the quantum computing device may comprise several additional permanent magnet devices. The additional permanent magnet devices may have the same size and / or properties as the permanent magnet devices described above in this document.

[0067] According to at least one embodiment, the quantum computing device further comprises at least one additional soft magnetic material surrounded by at least one additional permanent magnet device. The additional soft magnetic material may have the same shape and properties as the soft magnetic material described above herein.

[0068] According to at least one embodiment of the quantum computing device, the permanent magnet device has a rotational position relative to the additional permanent magnet device. For example, the additional permanent magnet device is arranged in a rotational form, in particular an out-of-plane rotational form, relative to the permanent magnet device, so that the corresponding main extension planes form an angle. That is, the additional main extension plane of the additional permanent magnet device is rotated out-of-plane with respect to the main extension plane of the permanent magnet device. Exemplarily, the angle can be between 0° and 180°, in particular can be 60°, 120° and / or 90°.

[0069] For example, the additional permanent magnet arrangement is rotated by 90° relative to the permanent magnet arrangement, so that the corresponding main extension planes enclose an angle of 90°.

[0070] In accordance with at least one embodiment of the quantum computing device, the permanent magnet arrangement and the additional permanent magnet arrangement are parallel to each other.

[0071] Exemplarily, the first axis and the additional first axis are positioned parallel to each other.

[0072] Alternatively, the additional permanent magnet arrangement is arranged in a rotational form, in particular in-plane rotational form, relative to the permanent magnet arrangement. In this case, the main extension plane and the additional main extension plane are parallel to each other. For such an in-plane rotation, an angle is formed by the corresponding first axis, i.e. the first axis and the additional first axis. Exemplarily, the angle can be between 0° and 90°.

[0073] For example, the additional permanent magnet arrangement is rotated 90° in a plane relative to the permanent magnet arrangement so that the corresponding first axes enclose an angle of 90°. In this embodiment, the first axis and the additional first axis are positioned perpendicular to each other.

[0074] Such an arrangement comprising the permanent magnet arrangement and the additional permanent magnet arrangement exemplarily each forms a three-dimensional confined space in terms of magnetic field, for example a three-dimensional gradient space.

[0075] For example, the additional soft magnetic material is arranged along an additional first axis of the additional permanent magnet arrangement.

[0076] In addition, a quantum computer is described, wherein the quantum computer comprises a quantum computing device as described above in this document. That is, the features about the quantum computer also apply to the quantum computing device, and vice versa.

[0077] The quantum computer is configured to perform quantum computing processing by using a quantum computing device. The trapped quantum particles of the quantum computing device can be particularly well controlled and manipulated using the permanent magnet device described above in this article to perform predetermined quantum computing.

[0078] Hereinafter, a quantum computing device will be described in more detail with reference to exemplary embodiments and associated drawings.

[0079] Figure 1 and Figure 2 Each shows a cross-sectional view of a quantum computing device according to an exemplary embodiment.

[0080] Figure 3 An exemplary graph showing magnetic field strength of a permanent magnet arrangement of a quantum computing device according to an exemplary embodiment.

[0081] Figure 4A quantum computer according to an exemplary embodiment is shown.

[0082] In the drawings, identical, similar or elements having the same effect are given the same reference numerals. The drawings and the proportions of the elements shown in the drawings should not be considered to be drawn to true scale. On the contrary, individual elements may be shown enlarged for better representation and / or for better comprehensibility.

[0083] according to Figure 1 The quantum computing device 1 of the exemplary embodiment includes a permanent magnet device 2. The permanent magnet device 2 includes 16 segments 3. The segments 3 surround a space 5 of the quantum computing device 1, and during operation of the quantum computing device 1, trapped quantum particles 6 are trapped in the space 5. The segments 3 surround the space 5 in the form of a ring. The center of each segment 3 is arranged at a point of the ring.

[0084] The permanent magnet device 2 has Figure 1 The main extension plane extending along the x-axis and y-axis shown in . Each segment 3 has a cross-sectional form of an annular sector or a circular ring sector, wherein all segments 3 share the same common inner ring and the same common outer ring. The width of each segment 3 tapers toward the space 5. That is, the relative edge of each segment 3 facing the space 5 is curved. The normal beam of the curved edge points in the direction away from the space 5. That is, the radius of the curved edge is defined relative to the central area of ​​the permanent magnet device 2.

[0085] The curved edges of the segments 3 arranged in opposite regions with respect to the central region and facing each other have a minimum distance of about 10 cm with respect to each other. The minimum distance divided by 2 defines the inner radius R of the permanent magnet arrangement 2 i .

[0086] Furthermore, each segment 3 has an extent along the corresponding minimum distance of approximately 20 cm. The minimum distance divided by 2 and the extent along the corresponding minimum distance define the outer radius R of the permanent magnet arrangement 2. o .

[0087] For example, directly adjacent segments 3 are spaced apart from each other. The edges of directly adjacent segments 3 facing each other have a distance of about 1 mm relative to each other.

[0088] In this exemplary embodiment, each segment 3 has a symmetry line that bisects the opposite edge facing the space 5. The symmetry lines are identical for segments 3 arranged opposite one another. One of the symmetry lines represents a first axis 7 of the permanent magnet arrangement 2, wherein the first axis 7 exemplarily extends in the main extension plane.

[0089] In addition, each segment 3 has a Figure 1The magnetization directions 4 of the arrows in the segments 3 in FIG. 4 are in opposite directions. The magnetization directions 4 of the segments 3 arranged in opposite regions relative to the center of the permanent magnet arrangement 2 point in opposite directions. A first axis 7 of the permanent magnet arrangement 2 is defined relative to two segments 3 arranged opposite to each other, wherein the magnetization directions 4 of the respective two segments 3 are parallel to the first axis 7.

[0090] Each magnetization direction 4 forms an angle with the first axis 7. All these angles are formed differently. For example, the angles of directly adjacent segments 3 differ from each other by 67.5°.

[0091] exist Figure 1 and Figure 2 In the exemplary embodiment of FIG. 1 , the first axis 7 points in the direction of the x-axis.

[0092] Furthermore, the angle of the segment 3 having the 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 the magnetization direction 4 parallel to the first axis 7 and pointing in the opposite direction as the first axis 7 is 180°.

[0093] Going clockwise along the loop from a segment 3 having a magnetization direction 4 parallel to the first axis 7 and pointing in the same direction as the first axis 7 back to this segment 3 , the magnetization direction 4 also rotates clockwise.

[0094] With such segments 3, the permanent magnet arrangement 2 is configured to generate a quadrupole field and thus have different strengths along the first axis 7, i.e. a magnetic field gradient along the first axis 7. Furthermore, during operation of the quantum computing device 1, the trapped quantum particles 6 are linearly arranged adjacent to each other along the first axis 7.

[0095] The strength of the magnetic field acting on the trapped quantum particles 6 is different for each trapped quantum particle 6 arranged on the first axis 7 .

[0096] Furthermore, the permanent magnet arrangement 2 has a soft magnetic material 60 arranged on the 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 extension direction along the first axis 7.

[0097] Exemplarily, the first portion 62 is the first end cap electrode 41 of the ion trap 100 and the second portion 63 is the second end cap electrode 42 of the ion trap 100. In this case, the first end cap electrode 41 and the second end cap electrode 42 form the yoke structure 60.

[0098] The center of the permanent magnet device 2 is located between the first portion 62 and the second portion 63. That is, the space 5 is located between the first portion 62 and the second portion 63.

[0099] The magnetic field of the permanent magnet device 2, in particular the strength of the magnetic field, is enhanced by about 10 times in the area of ​​the first portion 62 and the area of ​​the second portion 63, while the strength of the magnetic field is zero at the center of the permanent magnet device 2. That is, the difference in magnetic field strength increases from the first portion 62 to the center and from the second portion 63 to the center along the first axis 7.

[0100] Advantageously, particularly strong magnetic field gradients are achieved with such a quantum computing device 1 .

[0101] Exemplarily, the trapped quantum particles 6 are trapped ions.

[0102] For example, according to this exemplary embodiment, the inner radius R i is about 5cm, and the outer radius R o About 25cm. The remanence B of each segment in segment 3 R is, for example, 1 T. Therefore, the magnetic field, in particular the corresponding magnetic flux density It can be calculated by the following formula:

[0103]

[0104] The origin of the coordinates x and y is located in the center of the permanent magnet arrangement 2 .

[0105] Furthermore, the distance d between directly adjacent trapped ions is about 3 μm. Therefore, the magnetic flux density can be calculated for each position of the trapped ion. Therefore, differences in specific transitions between adjacent trapped ions can also be determined.

[0106] For example, the σ between directly adjacent trapped ions is ± The frequency difference of the transitions is at least 10 kHz and at most 100 MHz. ± The transition can be excited by left-circularly polarized or right-circularly polarized electromagnetic waves with polarization perpendicular to the local magnetic field.

[0107] For example, the frequency difference of the π transitions between directly adjacent trapped ions is at least 1 kHz and at most 10 MHz.Such π transitions are excited by linearly polarized electromagnetic waves with polarization parallel to the local magnetic field.

[0108] and Figure 1 Compared to the exemplary embodiment of Figure 2 The quantum computing device 1 of the exemplary embodiment comprises a permanent magnet arrangement 2 having segments 3, each segment 3 having the form of a square.

[0109] Each segment 3 has a square cross-sectional form. The magnetization direction 4 relative to the edge of the square is the same for each segment 3. Directly adjacent segments 3 are rotated relative to each other so that the magnetization direction 4 of each segment 3 corresponds to the Figure 1 angle.

[0110] exist Figure 3 , the intensity of the magnetic field in T represented by the absolute value of the magnetic field |B| shown on the vertical axis depends on the position x in mm shown on the horizontal axis.

[0111] Figure 3 The horizontal axis of the graph shown in corresponds to Figure 1 and Figure 2 The x-axis. The position x equal to 0 corresponds to Figure 1 and Figure 2 The center of the permanent magnet device 2.

[0112] The absolute value of the magnetic flux density |B| (i.e., the strength of the magnetic field) is symmetrical relative to the center of the permanent magnet arrangement 2. For negative position values ​​x, the absolute value of the magnetic flux density |B| (i.e., the strength of the magnetic field) has a negative slope, and for positive position values ​​x, the absolute value of the magnetic flux density |B| (i.e., the strength of the magnetic field) has a positive slope.

[0113] For the area of ​​±250 μm around the center of the permanent magnet device 2, the difference in the strength of the magnetic field is approximately linear. This causes a magnetic field gradient of about 200 T / m. The first part 62 and the second part 63 of the soft magnetic material 60 start at about -2 mm and about 2 mm x positions. That is, the distance between the first part 62 and the second part 63 along the first axis 7 is about 4 mm.

[0114] according to Figure 4 The quantum computer 8 of the exemplary embodiment includes a Figure 1 or Figure 2 A quantum computing device 1 of one of the exemplary embodiments of the invention and a quantum computing device 9 located in a chamber 10. The quantum computing device 9 is connected to external components of the quantum computer 8 via the chamber 10 through a plurality of connections 11. For example, the connection 11 connects the quantum computing device 9 with an external electronic device 12 and a classical computer 13.

[0115] For example, the quantum computing device 9 is configured to capture, manipulate and measure trapped quantum particles 6 in the space 5 during operation, each trapped quantum particle 6 being a qubit. To this end, the quantum computing device 9 may include electrodes, light guides and / or internal electronic devices including electronic devices. The electronic devices may include circuit systems, integrated electronic devices and / or detectors, such as photon detectors and / or charge detectors, controllers. Exemplarily, internal electronic devices are provided for preprocessing. For example, these components enable the measurement of the corresponding states of the qubits and enable gate operations on the qubits. Therefore, the quantum computing device 9 is configured to capture trapped quantum particles 6 and perform operations and measurements on the trapped quantum particles 6.

[0116] The quantum computing device 9 is installed in a chamber 10, wherein the chamber 10 may be an ultra-high vacuum chamber, an extremely high vacuum chamber and / or a cryostat. If the chamber 10 is an ultra-high vacuum chamber or an extremely high vacuum chamber, the permanent magnet device 2 may be arranged outside the chamber 10. In this case, the permanent magnet device 2 surrounds the chamber 10. Alternatively, the permanent magnet device 2 may also be arranged in an ultra-high vacuum chamber or an extremely high vacuum chamber or a cryostat.

[0117] Exemplarily, if the chamber 10 is a cryostat, the permanent magnet arrangement 2 is arranged inside the chamber 10 (not shown here). It is also conceivable that if the chamber 10 is a cryostat, the permanent magnet arrangement 2 can also be arranged outside the chamber 10 (not shown here).

[0118] The quantum computing device 9 is connected to an external electronic device 12 via a connection 11. The external electronic device 12 may be located at least partially inside the chamber 10 and partially outside the chamber 10. Furthermore, the external electronic device 12 is connected to a classical computer 13.

[0119] Exemplarily, the external electronic device 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 direct current signal generator. In addition, the external electronic device 12 may include transistor-transistor logic TTL.

[0120] Additionally, the external electronic device 12 may further include at least one laser system configured to cool the ions to be trapped. Additionally, the laser system may be configured to excite a specific state of the trapped ions.

[0121] For example, the classical computer 13 is configured to provide and receive digital signals. The digital signals correspond to control signals for operating the qubits and measurement signals corresponding to the states of the qubits.

[0122] The external electronic device 12 is configured in particular to convert digital signals into analog signals and vice versa. Thus, the external electronic device 12 is configured to provide the converted analog signals for manipulating the qubits to the quantum computing device 9. Furthermore, the external electronic device 12 is configured to provide the measured analog signals from the quantum computing device 9 to the classical computer 13, or to process such signals to directly initiate some response signals generated by the control electronic device 12.

[0123] The classical computer 13 is exemplarily configured to be equipped with a specific algorithm, i.e., a predetermined quantum calculation to solve a specific problem. The classical computer 13 is then configured to convert the compiled code corresponding to the algorithm into commands for the quantum computing device 9. These commands are then forwarded to the quantum computing device 9 via the external electronic device 12. In addition, the classical computer 13 is configured to receive the measurement results of the specific algorithm.

[0124] For example, all components of quantum computer 8 , in particular all electronic components of quantum computer 8 , are synchronized, for example, via an atomic clock reference.

[0125] The invention is not limited to the description of the exemplary embodiments. Rather, the invention covers any novel feature and any combination of features, any combination of features particularly including any combination of features in the claims, even if this feature or combination itself is not explicitly stated in the claims or exemplary embodiments.

[0126] Reference numerals list

[0127] 1Quantum computing device

[0128] 2 Permanent magnet device

[0129] 3 sections

[0130] 4 Magnetization direction

[0131] 5. Space

[0132] 6 Trapped Quantum Particles

[0133] 7First Axis

[0134] 8Quantum Computers

[0135] 9Quantum computing devices

[0136] 10 chambers

[0137] 11Connect

[0138] 12 External Electronic Devices

[0139] 13 Classical Computers

[0140] 100 ion trap

[0141] 40 end cap electrode

[0142] 41 first end cap electrode

[0143] 42 second end cap electrode

[0144] 50 substrates

[0145] 60 yoke structure

[0146] 61 Soft magnetic materials

[0147] 62 Part 1

[0148] 63 Part 2

[0149] d distance

[0150] R i inner radius

[0151] R o Outer Radius

Claims

1. A quantum computing device (1), comprising: - a permanent magnet arrangement (2) configured to create a magnetic field of different strengths for different positions on the first axis (7), - a space (5) for at least two trapped quantum particles (6) arranged along said first axis (7), and - a soft magnetic material (61) surrounded by the permanent magnet arrangement (2), the soft magnetic material (61) being configured to enhance the magnetic field established by the permanent magnet arrangement (2).

2. The quantum computing device (1) according to claim 1, wherein: The soft magnetic material (61) is a ferromagnetic material configured to be magnetized by the magnetic field established by the permanent magnet arrangement (2).

3. A quantum computing device (1) according to one of claims 1 to 2, wherein: The soft magnetic material (61) has a melting temperature of at least 500°C.

4. A quantum computing device (1) according to one of claims 1 to 3, wherein: The soft magnetic material (61) has a main extension direction along the first axis (7).

5. A quantum computing device (1) according to one of claims 1 to 4, wherein: - the soft magnetic material (61) has a relative magnetic permeability of at least 1000, and / or - The soft magnetic material (61) has a saturation magnetic flux density of at least 1 T.

6. A quantum computing device (1) according to one of claims 1 to 5, wherein: - the soft magnetic material (61) comprises iron, cobalt and vanadium, and -The content of iron and cobalt is greater than that of vanadium.

7. A quantum computing device (1) according to one of claims 1 to 6, wherein: The intensity of the magnetic field varies along the first axis (7) by at least 50 T / m.

8. A quantum computing device (1) according to one of claims 1 to 7, wherein: - the permanent magnet arrangement (2) comprises a plurality of segments (3), namely at least four segments (3), and - Each segment (3) has a magnetization direction (4).

9. The quantum computing device (1) according to claim 8, wherein: The magnetization directions (4) of the segments (3) arranged in opposite regions point in opposite directions.

10. The quantum computing device (1) according to one of claims 8 to 9, wherein: - said segment (3) surrounds said space (5) in the form of a ring, or The segment (3) surrounds the space (5) in the form of a polygonal outline.

11. A quantum computing device (1) according to one of claims 1 to 10, wherein: The remanence of each of the segments (3) is at least 0.1T and at most 1.5T.

12. A quantum computing device (1) according to one of claims 1 to 11, wherein: - the soft magnetic material (61) has a first portion (62) and a second portion (63), and - the first portion (62) and the second portion (63) are spaced apart from each other along the first axis (7).

13. A quantum computing device (1) according to one of claims 1 to 12, wherein: The first part (62) and the second part (63) form a yoke structure (60) within the permanent magnet arrangement (2).

14. The quantum computing device (1) according to one of claims 12 to 13, further comprising: - an ion trap (100), comprising a first end cap electrode (41) and a second end cap electrode (42), wherein the space (5) is located between the first end cap electrode (41) and the second end cap electrode (42), wherein: - the first portion (62) is formed as the first end cap electrode (41), and - the second portion (63) is formed as the second end cap electrode (42).

15. The quantum computing device (1) according to one of claims 1 to 13, further comprising: - an ion trap (100) for accommodating the space (5), comprising at least one substrate (50), wherein: - the at least one substrate (50) is formed to be electrically insulating, and - said first portion (62) and said second portion (63) are embedded in said at least one substrate (50).

16. The quantum computing device (1) according to one of claims 1 to 15, further comprising: - at least one additional permanent magnet arrangement (2), and - at least one additional soft magnetic material (61) surrounded by said at least one additional permanent magnet arrangement (2).

17. A quantum computer (8) comprising a quantum computing device (1) according to one of claims 1 to 16, the quantum computer (8) being configured to perform quantum computing.

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