CN115496221B

CN115496221B - Coupling structure and quantum chip

Info

Publication number: CN115496221B
Application number: CN202211442916.3A
Authority: CN
Inventors: 张辉; 曹亚昆
Original assignee: Origin Quantum Computing Technology Co Ltd
Current assignee: Benyuan Quantum Computing Technology Hefei Co ltd
Priority date: 2022-11-18
Filing date: 2022-11-18
Publication date: 2023-03-03
Anticipated expiration: 2042-11-18
Also published as: CN115496221A

Abstract

The application discloses coupling structure and quantum chip belongs to quantum chip and makes the field. The coupling structure includes a read bus, a read resonator, and a filter directly coupled to each. The coupling structure is used to perform a read operation on the qubit. It has the advantage of being easy to fabricate to the expected performance, yet avoids reading the qubit significantly shortening the qubit lifetime, and can be used to achieve high quality qubit reading.

Description

Coupling structure and quantum chip

Technical Field

The application belongs to the field of quantum chip preparation, and particularly relates to a test method and a test structure.

Background

In circuit quantum electrodynamics, a superconducting qubit is strongly coupled to a resonant cavity. This strong coupling can be used to achieve non-destructive measurement of the qubit states. However, a negative effect of this strong coupling interaction is to provide an additional channel for the dissipation of the qubit, thereby reducing the lifetime of the qubit.

Therefore, in order to realize fast and high-fidelity reading of qubits without causing a reduction in the qubit lifetime, it is common practice to introduce an additional filter circuit, such as a Purcell filter (pocell filter), to suppress the Purcell effect.

Due to the inherent characteristics of the prestel filter in terms of performance stability and bandwidth, the application of the prestel filter in a quantum chip with large-scale bits faces difficulties. For example, the yield of quantum chips is low, and the performance of the finished product is not in accordance with the design expectation. Therefore, how to use the prestel filter in the quantum chip in a more efficient manner is a matter of careful consideration.

Disclosure of Invention

In view of the above, the present application discloses a coupling structure and a quantum chip. The coupling structure can conveniently use the filter with high quality, thereby realizing effective reading of multiple quantum bits without causing large-amplitude attenuation of the service life of the quantum bits, and further improving the quality and yield of the quantum chips manufactured based on the coupling structure.

The scheme exemplified in the present application is implemented as follows.

In a first aspect, examples of the present application propose a coupling structure that can be used to perform a read operation on a qubit.

The coupling structure includes:

reading the bus;

a read resonator configured to couple with a qubit; and

a Possel filter directly coupled to the read bus and the read resonator, respectively;

the filter defining a first length defined by a region where the filter is coupled to the read bus, the read resonator defining a second length defined by a region where the read resonator is coupled to the filter;

the first length and the second length are each independently configured.

In this coupling structure, the read process between the qubit and the read resonator is influenced with a filter to avoid the lifetime of the qubit being adversely affected during the read process. Since the filter is directly coupled to the read bus and the read resonator, respectively, it is not necessary to connect the filter to the read bus and the read resonator, respectively, and it is also not necessary to couple the filter to the read bus and the read resonator using, for example, a capacitor. Therefore, the read bus and the read resonator can be manufactured relatively independently by directly coupling the filter with the read bus and the read resonator respectively, so that the manufacturing difficulty of the quantum chip is reduced, and the filter can be conveniently manufactured in a mode of meeting the expected performance of design because the influence of using capacitive coupling is avoided. By independent selection and configuration of the coupling lengths of the pursel filter and the read bus, respectively, the read resonator, adjustments such as coupling strength, etc. can be made to some extent to achieve a desired coupling scheme, control read operation.

According to some examples of the application, the read bus is a coplanar waveguide transmission line.

According to some examples of the application, the read resonator and the filter are coplanar waveguides, respectively.

According to some examples of the application, the read resonator and the filter are each independently selected from a quarter-wavelength coplanar waveguide or a half-wavelength coplanar waveguide.

According to some examples of the application, the read bus is a transmission line, and the read resonator and the filter are coplanar waveguides, respectively.

According to some examples of the application, the filter and the read resonator each have a curved section.

According to some examples of the present application, the read bus has an input port, a straight line segment, and an output port connected in sequence, the straight line segment extending in a first preset direction;

the filter is provided with a first bending section which extends and bends along a second preset direction, and the first preset direction and the second preset direction are criss-cross.

According to some examples of the application, the first curved section of the filter is located at an end of the filter.

According to some examples of the present application, a read resonator has a first coupling section, a second curved section, and a second coupling section connected in series;

wherein the first coupling section is coupled to the filter parallel line and the second coupling section is configured to couple to the qubit.

According to some examples of the present application, the read resonator has a first coupling section, a second curved section, and a second coupling connected in series;

wherein the first coupling section is coupled to the filter parallel line and the second coupling section is configured to couple to the qubit;

the first coupling section is remote from the first bending section.

According to some examples of the present application,

the first length is different from the second length.

According to some examples of the application, the first length is different than the second length;

and/or the reading resonator and the filter have a coupling distance in a coupling area, and the coupling strength of the reading resonator and the filter is determined by the second length and the coupling distance.

In a second aspect, examples of the present application propose a quantum chip. It comprises the following steps:

a qubit and the aforementioned coupling structure, and a read resonator in the coupling structure is coupled to the qubit.

According to some examples of the application, the number of qubits is a plurality, at least parts of which are directly or indirectly coupled to each other.

According to some examples of the application, the number of qubits is the same as the number of coupling structures and corresponds one to one.

Has the advantages that:

compared with the prior art, the coupling structure in the example of the application utilizes the filters directly coupled with the read bus and the read resonator respectively to favorably influence the coupling state between the qubit and the read resonator, so that the occurrence of a situation in which the lifetime of the qubit is significantly reduced during reading can be avoided. In addition, the mode of applying the filter in the coupling structure designed in this mode does not significantly increase the difficulty of manufacturing the quantum chip based on the mode (and accordingly increases the manufacturing yield), and can achieve the effect of suppressing the distortion of the performance of the filter.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments or the prior art of the present application, the drawings used in the embodiments or the prior art description will be briefly described below.

FIG. 1 is a schematic block diagram of a typical superconducting quantum computing system;

FIG. 2 is a schematic diagram of an exemplary arrangement in which the filter is placed on the read bus;

FIG. 3 is a schematic diagram of an exemplary filter disposed in a read cavity and coupled to the read cavity and a read bus via interdigital capacitors, respectively;

FIG. 4 is a schematic diagram of the principle structure of parallel line coupling in the embodiment of the present application;

FIG. 5 is a schematic structural diagram of a coupling structure in an example of the present application;

fig. 6 discloses a schematic structural diagram of a filter in the coupling structure of fig. 5;

fig. 7 discloses a schematic structural view of a read resonator in the coupling structure of fig. 5.

An icon: 100-superconducting quantum computing systems; 101-qubit unit; 102-an operation unit; 103-a reading unit; 201-a bus; 202-a resonant cavity; 203-a filtering unit; 204-interdigital capacitance; 300-a coupling structure; 301-read bus; 302-a filter; 303-read resonator.

Detailed Description

A typical superconducting quantum computing system has a structure substantially as shown in figure 1. Referring to fig. 1, a superconducting quantum computing system 100 includes a qubit unit 101 and an operating unit 102 and a reading unit 103 respectively matchingly associated therewith.

From a general functional point of view, the qubit unit 101 therein is used for providing and carrying quantum information for quantum computation; the operation unit 102 is mainly used for controlling the qubit unit 101 to perform quantum computation, such as bit logic gate computation; the reading unit 103 is used for reading the state information of the qubit unit 101 and the quantum computation result after the quantum computation.

In particular implementations, qubit unit 101 is placed in a cryogenic environment based on the properties of superconductivity. The low-temperature environment is mostly provided by a dilution refrigerator at present. Which can provide a temperature environment on the order of mk (millikelvin), for example. Because the dilution refrigerator is multi-stage refrigerated, qubit unit 101 is typically located at the lowest level of the dilution refrigerator. The other lines are gradually routed from the top layer to the bottom layer of the dilution refrigerator, and are finally matched and associated with the qubit unit 101, such as connection and coupling.

The operation unit 102 is configured to generate a corresponding operation signal, e.g. a series of microwave signals, in accordance with a quantum computing operation desired to be performed, in order to operate on, e.g. a quantum state, of a qubit. Accordingly, after the required operation is completed, the reading unit 103 may obtain a returned signal from the qubit, and further obtain relevant information of the qubit through corresponding signal processing, and finally obtain a calculation result.

In view of the vulnerability of superconducting qubits, some implementations choose to use a resonant cavity that can be strongly coupled to the qubit in order to achieve non-destructive measurement of the qubit, as mentioned above. Thus, these read structures typically include a read line and a resonant cavity that cooperate with the qubit and the read line, respectively. However, such a reading method leads to a reduction in the qubit lifetime to some extent, so that it is an option in practice to use, for example, a prestel filter.

In practice, the inventors have chosen a pursel filter that has two main modes of use: one solution is to place the filter on the read bus (bus-type purplug filter solution for short) and the other is to design the filter on the resonator (resonator-type purplug filter solution).

The scheme of placing the filter on the bus is shown in FIG. 2. For multi-qubit quantum chips, it is often necessary to read multiple cavity frequencies (of the resonant cavity 202) on a read bus. Therefore, the bandwidth of the passband or the bandwidth of the stopband of the prestart filter (filtering unit 203) is required to be sufficiently large. However, the bandwidth of the bandpass or bandstop of the bussed prestel filter is generally narrow, so that the number of resonators that can be coupled simultaneously in this solution is limited. On the other hand, the arrangement of the filtering unit 203 on the bus 201 may impose high requirements on the resonant cavity 202 and the fabrication process of the qubit, thereby causing a yield reduction in the fabrication process of the quantum chip.

If the pursel filter is disposed on the resonator 202 (as shown in fig. 3), the pursel filter (filter unit 203) is coupled to the resonator 202 and the bus 201 via the interdigital capacitor 204. Considering that the parameters of the interdigital capacitor 204 are easy to shift (have a non-negligible deviation from the theoretical design value) during actual manufacturing, the performance of the filter is deteriorated and even fails, and normal reading of the qubit is affected.

In these schemes, the Possel filter is designed to reject the frequency of the qubit, while passing the frequency of the resonant cavity 202. For example, when the frequency of the filter is the same as the frequency of the resonant cavity 202, the cavity frequency of the resonant cavity 202 may pass through the filter, but the frequency of the qubit may be suppressed from passing through.

In the resonator type purel filter scheme, the interdigital capacitor 204 exists between the bus 201 and the filter unit 203, and the Q value/quality factor of the filter is relatively high (Q is high, the pass band width is small), so that the frequency of the filter is not equal to the cavity frequency of the resonator 202, and the intended function of the filter cannot be realized.

Based on the foregoing practices and realisations, the inventors propose a new solution in the present examples. In contrast to placing the filter either to the bus or to the resonator, in the examples of this application the inventors chose to place a pursel filter between the resonator and the bus. The filter is directly coupled to the bus and resonator and therefore does not need to fabricate the interdigital capacitor 204. The scheme not only reduces the occupied space of the filter on the chip, but also reduces the preparation difficulty of the quantum chip on the process, thereby improving the yield of the quantum chip. In addition, since the interdigital capacitor 204 is not required to be used, performance variation due to the use of the interdigital capacitor 204 can be avoided, and the situation that the qubit cannot be effectively read due to the performance variation of the interdigital capacitor 204 does not occur.

The coupling structure 300 proposed by the inventor in the example is explained below with reference to the drawings (fig. 4, 5, 6, and 7). The coupling structure 300 may be used to perform a read operation on a qubit.

In an example, referring to fig. 5, a coupling structure 300 includes a read bus 301, a read resonator 303, and a filter 302. Wherein the filter 302 mediates signals between the read bus 301 and the read resonator 303. And the filter 302 is also directly coupled to the read bus 301, the read resonator 303, respectively. When the coupling structure 300 is used to perform a read operation on a qubit, the read cavity 303 is coupled to the qubit (not shown in FIG. 5) in addition to the filter 302. Thus, during transmission, the read signal for the qubit, after passing through the filter 302, acts on the qubit via the read resonator 303. As such, the read cavity 303 is coupled to the qubit.

In the above-described coupling structure 300, the use of a filter 302, such as a Purcell filter, can suppress the Purcell effect, thereby achieving fast and high-fidelity reading of qubits in a quantum computing system (e.g., a quantum computer) without causing a significant reduction in the lifetime of the qubits. In addition, in this scheme, neither the filter 302 is provided to the read bus nor the filter 302 is provided to the read cavity 303, so that both problems can be avoided.

Further, it can be known that the solution of the present example proposed by the inventor reduces the space occupied by the filter 302, thereby facilitating the layout of more components in the quantum chip, or more freely and leisurely laying out various lines and components. Meanwhile, the scheme can also reduce the preparation difficulty of the qubit, the chip and the like based on the scheme, thereby improving the yield in the manufacturing process.

In the coupling structure 300, the read bus 301 may alternatively be constructed in the form of a transmission line (e.g., a coplanar waveguide transmission line), while the filter 302 may be a prestel filter. Further, the read resonator 303 and the filter 302 may be coplanar waveguides, respectively. Still further, one or both may be constructed with quarter-wave coplanar waveguides (short-circuited at one end), respectively, based on frequency considerations; alternatively, one or both of the two may alternatively be constructed as a half-wavelength coplanar waveguide open at both ends. Or one of them is a quarter-wave coplanar waveguide and the other is a half-wave coplanar waveguide. In different construction modes, the size such as the length can be controlled and selected according to the actual frequency requirement.

In particular, in some examples, a read bus 301 in the form of a transmission line, and a read resonator 303 and a filter 302 in the form of a coplanar waveguide may be mated with the corresponding components in a parallel line coupling. For example, filter 302 is coupled in parallel with read bus 301 and filter 302 is coupled in parallel with read resonator 303. The structural principle of parallel line coupling is shown in fig. 4, and the parallel line coupling mainly comprises two close transmission lines which are parallel to each other; one of the lines is used as a main transmission line of signals, and the other line is used as a coupling line of signals. The two coupled transmission lines each have two ports for accessing different devices or lines, components, etc. In other examples, other forms of coupling, such as L-shaped coupling, may be selected if desired.

In view of the limited space of the qubit chip and the generally long length of the filter 302 and the read resonator 303 in the form of coplanar waveguides, in some examples bending of both (the filter 302 and the read resonator 303) may be chosen in order to make more use of space for laying out more lines, components, etc. Accordingly, the filter 302 and the read resonator 303 may each have curved sections due to the curved construction.

As an example, the read bus 301 has, for example, an input port, a straight line segment, and an output port connected in sequence from one end to the other, adapted for parallel line coupling. For convenience of illustration, the straight line segment of the read bus 301 extends along a first predetermined direction that is preselected. Therefore, based on the parallel line coupling method, it can be known that, at the straight line segment position of the read bus 301, the filter 302 and the read resonator 303 also correspond to segments having a straight line distribution extending along the first preset direction.

In connection with the foregoing, the filter 302 has a curved portion in order to save space.

For example, the filter 302 has a first curved section extending and curved along a second predetermined direction. The first preset direction and the second preset direction are criss-cross. Exemplarily, in fig. 5, the first preset direction is, for example, a horizontal direction, and the second preset direction is, for example, a vertical direction. The first curved section of the filter 302 may be located at different locations thereof, configured as desired.

For example, in fig. 5, the first curved section of the filter 302 is located at one of the ends of the filter 302; other examples may be at both ends, so it may have two curved sections. In other examples, the pattern length of the Purcell filter 302 is ensured to meet the expected design, the specific bending form is varied, the flexibility is high when the pattern is drawn, and the method is mainly associated with space occupation and a manufacturing process.

For the read resonator 303, it needs to be coupled to the qubits, and the filter 302, respectively, so it has two coupling sections; for the sake of distinction, the two coupling sections are described as a first coupling section and a second coupling section, respectively.

In combination with the bend to reduce space usage, the read resonator 303 illustratively has a first coupled section, a second bent section, and a second coupled section connected in series. That is, the two ends of the read resonator 303 are the first coupled section and the second coupled section, respectively, and the second bending section is located between the two ends. The number of second curved sections may be provided as one or two, or more, according to different examples; in fig. 5 and 7, the number of the second bending sections is two, and a linear section with a proper length is arranged between the two bending sections.

Since the read resonator 303 and the filter 302 may take parallel line coupling, one of the first coupling section and the second coupling section may be configured in a linear structure. For example, in fig. 5, the first coupling section is coupled to the filter 302 in a parallel line, so that the first coupling section is linear and the second coupling section is configured to couple to a qubit.

In some examples, the arrangement of the read resonator 303 and the filter 302 may be selected such that the first coupled section of the read resonator 303 is away from the first curved section of the filter 302, in view of the structure of the read resonator 303 and the filter 302.

Since the filter 302 is coupled to the read bus 301, the read resonator 303, respectively, the coupling strength is associated with a number of factors (e.g., the distance between the elements, the coupling length, the physical size of the elements, etc.) in the coupling area. And further may be related to performance indicators such as frequency of each element, and may be adjusted accordingly taking into account one or more of these factors.

For example, the length of the elements in the coupling region or further in combination with the spacing is chosen as an adjustment factor. For example, the read resonator 303 and the filter 302 are defined to have a perpendicular distance from each other in the coupling region described as a coupling pitch, and thus the coupling strength of the read resonator 303 and the filter 302 may be determined by the second length and the coupling pitch together.

For the purpose of this description, the following explanation may be made: the filter 302 is defined with a first length L2, and the first length L2 is defined by the area where the filter 302 is coupled to the read bus 301; the read resonator 303 defines a second length L1, and the second length L1 is defined by a region where the read resonator 303 is coupled to the filter 302, please refer to fig. 6 and 7 together. The first length and the second length may be the same or may be different (e.g., the first length is greater than the second length). The first length and the second length are each independently configured to satisfy adjustments, controls, such as coupling strength, read operations, and the like. Further, the first length and the second length may also be associated with each other, such that when one is changed, the other is correspondingly adjusted, so as to achieve a better effect.

In addition, the total length L of each of the filter 302 and the read resonator 303 may be the same, and may of course be configured differently; the specific selection can be controlled according to actual requirements, and the application is not particularly limited.

The length of the coupling section in combination with the above can be used to control and adjust different characteristics in the coupling structure 300. For example:

(1) The bandwidth of Purcell is controlled by adjusting the coupling length L2 of the filter 302 and further adjusting the Q value of the filter 302, and the adjustable range is large.

(2) The co-planar waveguide coupling replaces the interdigital capacitor 204, so that the frequency of the Purcell filter 302 can be better controlled, and can be accurately controlled only by being influenced by the total length L of the filter 302.

(3) The coupling length L1 of the read resonator 303 and the Purcell filter 302 control the coupling strength by varying the coupling length L1 length and the relative position of the two.

In the example of the application, the mode that the Purcell filter 302 is directly coupled with the reading bus and the reading resonant cavity is used for replacing the scheme design of coupling through the interdigital capacitor 204, so that the preparation difficulty in the process can be reduced, and the yield of chips is improved. When the quantum chip is applied to a multi-bit quantum chip, by placing a separate Purcell filter 302 for each resonant cavity, the qubits/qubits can be protected from the influence of Purcell decay, and the non-resonant drive of adjacent resonators is also suppressed, thereby avoiding the random dephasing of the qubits.

To facilitate those skilled in the art to implement the solution illustrated in the present application more conveniently, the fabrication process of the coupling structure 300 can be briefly described as follows: for example, silicon is selected as the substrate, and a superconducting thin film, such as an aluminum/Al film, is formed on the surface of the substrate by evaporation, sputtering, deposition, or the like. And preparing a pre-designed layout structure comprising a Purcell filter 302 graph on the Al film or on the basis of equipment and processes such as Al film combined film making, mask plate making, photoetching and etching. During the manufacturing process, the read bus 301, the read resonator 303, and the filter 302 in the coupling structure 300 may be prepared in sequence in different steps.

On the basis of the foregoing coupling structure 300, as an example of its application, a quantum chip is proposed. The quantum chip includes a qubit and a coupling structure 300, and a read resonator 303 in the coupling structure 300 is coupled to the qubit. The read resonator 303 and the qubit coupling may be in-plane coupling or out-of-plane coupling; in addition, the two can also be directly coupled or indirectly coupled. The manner in which the read resonator 303 is coupled to the qubit may depend on the implementation of the qubit.

In a quantum chip, a plurality of qubits are typically provided, and each of the qubits may independently have a read resonator 303 coupled thereto. Therefore, in some examples, the number of qubits is the same as the number of read resonators 303 of coupling structure 300, and corresponds one-to-one. In some examples, a relatively long read bus 301 may be selected and configured based on the plurality of filters 302 and the plurality of read resonators 303, and thus may be coupled with a plurality of qubits to achieve a smaller number of configured read buses 301 and to reduce the difficulty of layout of the multi-read bus 301. Second, at least portions of the qubits in the quantum chips may also be coupled to one another, directly or indirectly, to implement the required quantum logic gates.

The coupling structure 300 of the quantum chip has the same structure as the coupling structure 300 in the above embodiments or a similar structure formed by being appropriately adjusted according to the requirement, and has the same beneficial effects as above, and therefore, the description is omitted. For technical details that are not disclosed in the embodiments of the quantum chip of the present application, those skilled in the art should refer to the description of the superconducting structure above for understanding, and for brevity, will not be described again here.

The embodiments described above with reference to the drawings are exemplary only for the purpose of illustrating the present application and are not to be construed as limiting the present application. To make the objects, technical solutions and advantages of the embodiments of the present application clearer, the foregoing description explains the embodiments of the present application in detail with reference to the accompanying drawings. However, it will be appreciated by those of ordinary skill in the art that in the examples of the present application, numerous technical details are set forth in order to provide a better understanding of the present application. However, the technical solution claimed in the present application can be implemented without these technical details and various changes and modifications based on the following embodiments. The division of each example is for convenience of description, and should not constitute any limitation to the specific implementation manner of the present application, and the embodiments may be mutually incorporated and referred to without contradiction.

It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It should be understood that the data so used may be interchanged under appropriate circumstances such that embodiments of the application described herein may be implemented in sequences other than those illustrated or described herein.

Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The construction, features and functions of the present application are described in detail in the embodiments illustrated in the drawings, which are only preferred embodiments of the present application, but the present application is not limited by the drawings, and all equivalent embodiments that can be modified or changed according to the idea of the present application are within the scope of the present application without departing from the spirit of the present application.

Claims

1. A coupling structure for performing a read operation on a qubit, the coupling structure comprising:

reading a bus;

a read resonator configured to couple with a qubit; and

a Possel filter directly coupled to the read bus and the read resonator in parallel line coupling;

the Possel filter defining a first length defined by a region where the filter is coupled to the read bus, the read resonator defining a second length defined by a region where the read resonator is coupled to the filter;

the first length and the second length are each independently configured.

2. The coupling structure of claim 1, wherein the read bus is a coplanar waveguide transmission line.

3. The coupling structure according to claim 1 or 2, characterized in that the read resonator and the filter are respectively coplanar waveguides.

4. The coupling structure of claim 3, wherein the read resonator and the filter are each independently selected from a quarter-wavelength coplanar waveguide or a half-wavelength coplanar waveguide.

5. The coupling structure of claim 1, wherein the read bus is a transmission line, and the read resonator and the filter are each a coplanar waveguide.

6. The coupling structure of claim 5, wherein the filter and the read resonator each have a curved section.

7. The coupling structure according to claim 5, wherein the read bus has an input port, a straight line segment and an output port connected in sequence, the straight line segment extending along a first predetermined direction;

8. The coupling structure of claim 7, wherein the first curved section of the filter is located at an end of the filter.

9. The coupling structure according to any one of claims 5, 7 or 8, wherein the read resonator has a first coupling section, a second curved section and a second coupling section connected in sequence;

10. The coupling structure of claim 8, wherein the read resonator has a first coupling section, a second curved section, and a second coupling connected in series;

the first coupling segment is distal from the first curved segment.

11. The coupling structure of claim 5, wherein the first length is different from the second length.

12. The coupling structure of claim 11, wherein the first length is different than the second length;

13. A quantum chip, comprising:

a quantum bit; and

the coupling structure of any one of claims 1 to 12;

a read resonator in a coupling structure is coupled to the qubit.

14. The quantum chip of claim 13, wherein the quantum bit is in a plurality, at least some of which are coupled to each other directly or indirectly.

15. The quantum chip of claim 14, wherein the number of qubits is the same as the number of coupling structures and corresponds to one.