Quantum information processing system and quantum information processing method for a quantum information processing system

Abstract

To provide a quantum information processing system capable of performing a quantum operation while suppressing the disorder of a spin state of a quantum bit.SOLUTION: A quantum information processing system comprises a quantum bit array and a control device. The quantum bit array includes a plurality of quantum dots, which can trap quantum bits, and a plurality of gate electrodes used to control the plurality of quantum bits. The control device controls the plurality of quantum bits trapped in the quantum bit array using the plurality of gate electrodes. The quantum bit array also includes a storage region having a plurality of quantum dots for storing quantum bits, and an operation region having a plurality of quantum dots which can add a quantum gate operation for changing the spin state for the trapped quantum bits. The control device performs a shuttle operation to move the quantum bits stored in the storage region by a Coulomb force generated using the plurality of gate electrodes from the storage region to the operation region, and further performs a quantum gate operation for changing the spin state for the quantum bits in the operation region.SELECTED DRAWING: Figure 4

Description

Technical Field

[0004] , , , ,

[0005] , , ,

[0001] The present invention relates to a quantum information processing system that performs quantum gate operations for changing the spin state of a plurality of qubits, and a quantum information processing method of the quantum information processing system.

Background Art

[0002] In a quantum computer, in order to perform large-scale operations, it is essential to generate and operate a large number of qubits. Therefore, there is a technique for generating and operating a large number of qubits in a quantum computer. Patent Document 1 describes a quantum information processing device having fins formed of a semiconductor with electrons as qubits. Here, a plurality of qubits can be arranged in a two-dimensional square lattice on the fins and moved. Further, the quantum information processing device can perform quantum gate operations for changing the spin state of the qubits existing on the fins.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, generally, in a quantum computer that generates and operates electrons as qubits, a static magnetic field or an electromagnetic pulse is applied to the qubits to be operated for operation. Due to the static magnetic field or electromagnetic pulse applied to operate the qubits to be operated, there is a possibility that the spin state of the qubits around the qubits to be operated may be disturbed, such as a change in amplitude or a rotation of phase. As a result, there is a problem that it becomes difficult to perform calculations using qubits.

[0005] The present invention aims to provide a quantum information processing system and a quantum information processing method for a quantum information processing system that can perform quantum operations while suppressing disturbances in the spin state of qubits. [Means for solving the problem]

[0006] To achieve the above objective, one aspect of the quantum information processing system of the present invention is a quantum information processing system that performs a quantum gate operation to change the spin state of a plurality of qubits, wherein the quantum gate operation is applied to the qubit that is the target of the quantum gate operation when the distance between the qubit that is the target of the quantum gate operation and the qubits surrounding the qubit is greater than a predetermined distance that can suppress disturbance of the spin state due to the quantum gate operation when the quantum gate operation is applied to the qubit that is the target of the quantum gate operation.

[0007] Furthermore, one aspect of the quantum information processing system of the present invention is a quantum information processing system that performs quantum gate operations to change the spin state of a plurality of qubits, The system comprises a qubit array having a plurality of quantum dots capable of confining the qubits and a plurality of gate electrodes used to control the plurality of quantum dots, and a control device that controls the plurality of qubits confined in the qubit array using the plurality of gate electrodes, wherein the qubit array has a storage area having a plurality of quantum dots for storing the qubits and an operation area having a plurality of quantum dots capable of performing the quantum gate operation that changes the spin state of the confined qubits, and the control device moves the qubits stored in the storage area from the storage area to the operation area by shuttle operation that moves the qubits using the Coulomb force generated by the plurality of gate electrodes, and further performs the quantum gate operation that changes the spin state of the qubits in the operation area.

[0008] Furthermore, one embodiment of the quantum information processing method for the quantum information processing system of the present invention is a quantum information processing method in a quantum information processing system that performs quantum gate operations to change the spin state of a plurality of qubits, wherein the quantum information processing system comprises a qubit array having a plurality of quantum dots capable of confining the qubits and a plurality of gate electrodes used to control the plurality of quantum dots, and a control device that controls the plurality of qubits confined in the qubit array using the plurality of gate electrodes, wherein the qubit array has a storage area having a plurality of quantum dots for storing the qubits, and an operation area having a plurality of quantum dots capable of applying the quantum gate operations to change the spin state of the confined qubits, wherein the control device moves the qubits stored in the storage area from the storage area to the operation area by shuttle operation that moves the qubits using the Coulomb force generated by the plurality of gate electrodes, and further causes the control device to perform the quantum gate operations to change the spin state of the qubits in the operation area. [Effects of the Invention]

[0009] According to the present invention, quantum operations can be performed while suppressing disturbances in the spin state of the qubit.

[0010] Other issues, configurations, and effects not mentioned above will be clarified by the following description of embodiments for carrying out the invention. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 shows an example of a functional block diagram of an embodiment of a quantum information processing system. [Figure 2] Figure 2 is a block diagram showing an example of the hardware configuration of the control device according to the embodiment. [Figure 3] Figure 3 is a schematic perspective view of the quantum computing device according to the embodiment. [Figure 4] Figure 4 is a schematic exploded perspective view of the quantum computing device of the embodiment. [Figure 5] FIG. 5 is an example of a circuit diagram of a qubit array of a quantum computing device in an initial state. [Figure 6] FIG. 6 is a diagram for explaining the operation of a controlled NOT gate that changes the state of the spin of an electron for two electrons moved to an operation region. [Figure 7A] FIG. 7A is a circuit diagram of a quantum computing device in the process of the processing of operation example 1. [Figure 7B] FIG. 7B is a circuit diagram of a quantum computing device in the process of the processing of operation example 1. [Figure 7C] FIG. 7C is a circuit diagram of a quantum computing device in the process of the processing of operation example 1. [Figure 7D] FIG. 7D is a circuit diagram of a quantum computing device in the process of the processing of operation example 1. [Figure 7E] FIG. 7E is a circuit diagram of a quantum computing device in the process of the processing of operation example 1. [Figure 8A] FIG. 8A is a circuit diagram of a quantum computing device in the process of the processing of operation example 2. [Figure 8B] FIG. 8B is a circuit diagram of a quantum computing device in the process of the processing of operation example 2. [Figure 8C] FIG. 8C is a circuit diagram of a quantum computing device in the process of the processing of operation example 2. [Figure 8D] FIG. 8D is a circuit diagram of a quantum computing device in the process of the processing of operation example 2. [Figure 8E] FIG. 8E is a circuit diagram of a quantum computing device in the process of the processing of operation example 2. [Figure 8F] FIG. 8F is a circuit diagram of a quantum computing device in the process of the processing of operation example 2. [Figure 8G] FIG. 8G is a circuit diagram of a quantum computing device in the process of the processing of operation example 2. [Figure 9A] FIG. 9A is a circuit diagram of a quantum computing device in the process of the processing of operation example 3. [Figure 9B] FIG. 9B is a circuit diagram of a quantum computing device in the process of the processing of operation example 3. [Figure 9C]FIG. 9C is a circuit diagram of a quantum computing device in the process of the processing of Calculation Example 3. [Figure 9D] FIG. 9D is a circuit diagram of a quantum computing device in the process of the processing of Calculation Example 3. [Figure 9E] FIG. 9E is a circuit diagram of a quantum computing device in the process of the processing of Calculation Example 3. [Figure 10] FIG. is an example of the arrangement of the storage area, the operation area, and the transfer area in the qubit array of the quantum information processing system of Modification Example 3. [Figure 11] FIG. is an example of the arrangement of the storage area, the operation area, and the transfer area in the qubit array of the quantum information processing system of Modification Example 4. [Figure 12] FIG. is an example of the arrangement of the storage area, the operation area, and the transfer area in the qubit array of the quantum information processing system of Modification Example 5. [Figure 13] FIG. is an example of the arrangement of the storage area and the operation area in the qubit array of the quantum information processing system of Modification Example 6. [Figure 14] FIG. is an example of the arrangement of the storage area and the operation area in the qubit array of the quantum information processing system of Modification Example 7.

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. When the X-axis, Y-axis, and Z-axis are shown in the drawings, the axes are orthogonal to each other.

[0013] The embodiments and modifications are illustrative examples for illustrating the present invention, and have been omitted and simplified as appropriate for clarity of explanation. The present invention can be implemented in various other forms. Unless otherwise specified, each component may be singular or plural. Furthermore, the position, size, shape, and range of each component shown in the drawings may not represent the actual position, size, shape, and range in order to facilitate understanding of the invention. For this reason, the present invention is not necessarily limited to the position, size, shape, and range disclosed in the drawings. When there are multiple components having the same or similar function, they may be described using the same reference numeral with different subscripts. Furthermore, when it is not necessary to distinguish between these multiple components, the subscripts may be omitted in the description.

[0014] The quantum information processing system 1 of this embodiment is a type of quantum computer. The quantum information processing system 1 performs quantum gate operations that change the spin state of multiple qubits. Note that the qubits can be charged particles, and instead of electrons, ions may also be used.

[0015] <<Configuration of Quantum Information Processing System 1 (Figures 1-6)>> Figure 1 is a diagram showing an example of a functional block diagram of the quantum information processing system 1 of an embodiment. As shown in Figure 1, the quantum information processing system 1 includes a quantum computing device 100 that manipulates electrons, which are qubits, a control device 200 that controls the quantum computing device 100, and a measuring device 300 that measures the state of electrons. Details of the quantum computing device 100 will be described later. The control device 200 has a qubit processing unit 210 that controls the quantum computing device 100. The measuring device 300 is connected to the quantum computing device 100 and the control device 200. The measuring device 300 measures the state of electrons (qubits), such as the number of electrons (qubits), related to the electrons output from the quantum computing device 100, and outputs the measurement result to the control device 200. The state of electrons (qubits) measured by the measuring device 300 is the result of the quantum computation.

[0016] Figure 2 shows an example of the hardware configuration of the control device 200. As shown in Figure 2, the control device 200 has a hardware configuration that includes a processor 211, main memory 212, secondary memory 213, input / output devices 214, a quantum computing device I / F 215 connected to the quantum computing device 100, and a bus 216 connecting these. The control device 200 may also be a dedicated circuit that performs specific processing, such as an FPGA (Field Programmable Gate Array), ASIC (Application Specific Integrated Circuit), or CPLD (Complex Programmable Logic Device).

[0017] The processor 211 reads data and programs stored in the sub-memory 213 into the main memory 212 and executes the processing defined by the program. The main memory 212 is a device that stores programs and data, etc., and has volatile memory elements such as RAM. The sub-memory 213 is a device such as an HDD (Hard Disk Drive) or SSD (Solid State Drive) that stores programs and data, etc., and has non-volatile memory elements. The sub-memory 213 stores the qubit processing program 210a. The processor 211 realizes the qubit processing unit 210 by reading the qubit processing program 210a stored in the sub-memory 230 into the main memory 220 and executing it. In this specification, when describing processing in a sentence with the qubit processing unit 210 as the subject, it indicates that the processor 211 of the control device 200 is executing the qubit processing program 210a that realizes the qubit processing unit 210.

[0018] The input / output device 240 includes devices that accept user input, such as a keyboard and a mouse, and devices that output information, such as a display, and is capable of accepting user input and presenting information to the user.

[0019] The user inputs the details of the qubit-based operation to the control device 200 using the input / output device 240. The processor 211 of the control device 200 takes the details of the qubit-based operation input by the user as input and executes the processing of the qubit processing program 210a. In the processing of the qubit processing program 210a, the quantum computing device 100 is used to perform the qubit-based operation.

[0020] Figure 3 is a schematic perspective view of the quantum computing device 100. Figure 4 is a schematic decomposed perspective view of quantum information processing.

[0021] As shown in Figure 3, the quantum computing device 100 includes a computing layer 110, a first gate electrode layer 120, a second gate electrode layer 130, a magnet 140, and a magnetic shield 150. The quantum computing device 100 forms a qubit array 100A with the computing layer 110, the first gate electrode layer 120, and the second gate electrode layer 130, as described below.

[0022] As shown in Figure 4, the arithmetic layer 110 has an arithmetic layer body 111 and an arithmetic region 112 formed inside the arithmetic layer body 111. The arithmetic layer body 111 is made of a P-type semiconductor (for example, P-type Si). The arithmetic layer body 111 is connected to a control device 200. The control device 200 can change the potential of the arithmetic layer body 111.

[0023] The computation region 112 is formed of an intrinsic semiconductor (for example, intrinsic Si). The control device 200 can perform quantum computation operations such as confining electrons, which are qubits, in the computation region 112 and moving electrons confined in the computation region 112. The computation region 112 has X sections 112x1, 112x2, and 112x3 that are spaced apart from each other and extend in the X-axis direction, and a Y section 112y1 that connects the X sections 112x1, 112x2, and 112x3 and extends in the Y-axis direction. The control device 200 can move electrons, which are quantum dots, in and out from the terminals Res1 and Out1 of the X section 112x1, the terminals Res2 and Out2 of the X section 112x2, the terminals Res3 and Out3 of the X section 112x3, and the terminals Resy and Outy of the Y section 112y1. Therefore, the control device 200 can move electrons in and out of the computation area 112 from outside the qubit array 100A.

[0024] Terminals Out1 of X section 112x1, Out2 of X section 112x2, and Out3 of X section 112x3 of the calculation area 112 are connected to the measuring device 300 (not shown in Figures 3 and 4).

[0025] The measuring device 300 measures the state of electrons (qubits), such as the number of electrons (qubits), related to the electrons output from terminal Out1 of X section 112x1, terminal Out2 of X section 112x2, and terminal Out3 of X section 112x3 in the calculation area 112, and outputs the measurement results to the control device 200. The state of electrons (qubits) measured by the measuring device 300 is the result of the quantum operation.

[0026] The first gate electrode layer 120 is connected to the control device 200 and has gate electrodes XJ0-XJ6 and XQ1-XQ6 extending in the Y-axis direction. Gate electrode XJ is a collective term for gate electrodes XJ0-XJ6. Gate electrode XQ is a collective term for gate electrodes XQ1-XQ6. Gate electrodes XQ and gate electrodes XJ are arranged alternately along the X-axis direction. Furthermore, each gate electrode XJ0-XJ6 and XQ1-XQ6 is insulated from adjacent gate electrodes XJ and XQ. The control device 200 can apply voltages of different potentials to each of the gate electrodes XJ0-XJ6 and XQ1-XQ6.

[0027] The second gate electrode layer 130 is connected to the control device 200 and has gate electrodes YJ0-YJ3 and YQ1-YQ3 extending in the Y-axis direction. Gate electrode YJ is a collective term for gate electrodes YJ0-YJ3. Gate electrode YQ is a collective term for gate electrodes YQ1-YQ3. As shown in Figure 4, gate electrode YJ3 has a projection YJ3a that protrudes in the Z-axis direction (-Z direction). As shown in Figure 3, the projection YJ3a penetrates the first gate electrode layer 120 and is close to the Y-section 112Y1 of the calculation area 112 of the calculation layer 110. Each of the gate electrodes YJ0-YJ2 and YQ1-YQ3 has a projection similar to the projection YJ3a of gate electrode YJ3, and the collective term for this projection is "projection Ya".

[0028] The gate electrodes YQ and YJ are arranged alternately along the Y-axis. Furthermore, each of the gate electrodes YJ0-YJ3 and YQ1-YQ3 is insulated from the adjacent gate electrodes YJ and YQ. The control device 200 can apply voltages of different potentials to each of the gate electrodes YJ0-YJ3 and YQ1-YQ3. In addition, by applying voltages of different potentials to each of the gate electrodes YJ0-YJ3 and YQ1-YQ3, the control device 200 can apply voltages from the protruding portions Ya of each of the gate electrodes YJ0-YJ3 and YQ1-YQ3 to the quantum dots DY1-DY3 and BY0-BY3 of the Y section 112y1 of the computing layer 110, which will be described later.

[0029] The magnet 140 exerts a magnetic force on the calculation area 112 of the calculation layer 110.

[0030] The magnetic shield 150 blocks the magnetic force of the magnet 140.

[0031] Multiple N-channel field-effect transistors (FETs) are formed in the calculation region 112 of the calculation layer 110, the first gate electrode layer 120, and the second gate electrode layer 130. Specifically, N-channel field-effect transistors (FETs) are formed at the locations where the X portions 112x1, 112x2, and 112x3 of the calculation region 112 of the calculation layer 110 overlap with the gate electrodes XJ0-XJ6 and XQ1-XQ6 of the first gate electrode layer 120, and the gate electrodes YJ0-YJ3 and YQ1-YQ6 of the second gate electrode layer 130. In addition, N-channel field-effect transistors (FETs) are also formed at the locations where the Y portion 112y1 of the calculation region 112 of the calculation layer 110 overlaps with the protruding portions Ya of the gate electrodes YJ0-YJ2 and YQ1-YQ3. The control device 200 can use these N-channel field-effect transistors (FETs) as quantum dots that confine electrons, which are qubits, or as potential barriers between quantum dots.

[0032] The regions where the X portions 112x1, 112x2, and 112x3 of the computation region 112 of the computation layer 110 overlap with the gate electrodes XQ1-XQ6 of the first gate electrode layer 120 and the gate electrodes YQ1-YQ6 of the second gate electrode layer 130 overlap are used as quantum dots. The quantum dot where gate electrode XQi and gate electrode YQj overlap is represented as the quantum dot "Dij". Then, in the initial state described later, the electrons confined in quantum dot Dij are represented as "eij".

[0033] On the other hand, the overlapping areas of the X portions 112x1, 112x2, and 112x3 of the calculation region 112 of the calculation layer 110, the gate electrodes XJ0-XJ6 of the first gate electrode layer 120, and the gate electrodes YQ1-YQ6 of the second gate electrode layer 130 are also used as potential barriers. The field-effect transistor of the potential barrier at the overlapping area of ​​gate electrode XJi and gate electrode YQj is denoted as "potential barrier Bij".

[0034] The area where the Y portion 112y1 of the first gate electrode layer 120 overlaps with the protrusions Ya of gate electrodes YQ1-YQ3 is also used as a quantum dot. The quantum dot at the overlapping area of ​​the Y portion 112y1 of the first gate electrode layer 120 and the protrusion Ya of gate electrode YQi is denoted as "quantum dot Dyi". Then, in the initial state described later, the electrons confined in quantum dot Dyi are denoted as "electrons eyi".

[0035] The area where the Y portion 112y1 of the first gate electrode layer 120 and the protruding portions Ya of gate electrodes YJ0-YJ3 overlap is also used as a potential barrier. The field-effect transistor of the potential barrier at the area where the Y portion 112y1 of the first gate electrode layer 120 and the protruding portion Ya of gate electrode YJi overlap is represented as "potential barrier BYi".

[0036] Furthermore, the control device 200 can change the potential by applying voltage to the gate electrodes XQ, XJ, YQ, and YJ, or by applying a direct current or alternating current to generate pulses. As a result, as will be described in detail later, the control device 200 can confine electrons, which are qubits, to quantum dots, and move electrons between quantum dots. In addition, the control device 200 can perform quantum gate operations that change the spin state of electrons (qubits), such as controlling the phase of the electron spin and operating controlled NOT gates.

[0037] Furthermore, the control device 200 can input and output electrons (qubits) from terminals Res1, Out1, Res2, Out2, Res3, Out3, Resy, and Outy of the arithmetic domain 112.

[0038] Therefore, the control device 200 can perform initialization including the operation of confining the qubits in quantum dots, a rotation gate operation which is a 1-qubit gate, a controlled NOT gate operation which is a 2-qubit gate, and output electrons (qubits) from terminals Out1, Out2, and Out3 of the operation area 112 to the measuring device 300, allowing the measuring device 300 to measure the state of the electrons (qubits). As a result, the quantum information processing system 1 is capable of performing any quantum operation.

[0039] As described above, the quantum computing device 100 forms a qubit array 100A with a computing layer 110, a first gate electrode layer 120, and a second gate electrode layer 130, as described below. As explained above, the qubit array 100A has a plurality of quantum dots that can confine electrons (qubits) and a plurality of gate electrodes used to control the plurality of quantum dots.

[0040] The qubit array 100A is provided with a storage area A1, an operation area A2, and a movement area A3.

[0041] Storage region A1 is a region that has multiple quantum dots that store electrons (qubits). As shown in Figure 4, storage region A1 includes quantum dots D11-D31, D12-D32, and D13-D33.

[0042] Operational region A2 is a region containing multiple quantum dots on which quantum gate operations can be applied to change the spin state of confined electrons (qubits). As shown in Figure 4, operational region A2 includes quantum dots D41, D51, D42, D52, D43, and D53.

[0043] Furthermore, the movement region A3 is a region containing quantum dots used for the movement of electrons (qubits). The movement region A3 is located between the storage region A1 and the operation region A2. As shown in Figure 4, the movement region A3 includes quantum dots Dy1-Dy3.

[0044] The allocation of storage area A1, operation area A2, and movement area A3 is determined by the qubit processing program 210a of the control device 200. The quantum information processing system 1 can appropriately change the allocation of storage area A1, operation area A2, and movement area A3 during the processing of the qubit processing program 210a. For example, the quantum information processing system 1 can change the size of storage area A1 according to the number of qubits used in the operation, and can also change the size of operation area A2 according to the number of quantum dots required for quantum gate operations. Furthermore, the quantum information processing system 1 can change the shape of movement area A3 according to the content of the operation.

[0045] Figure 5 is an example of a circuit diagram of the qubit array 100A of the quantum computing device 100 in its initial state. As shown in Figure 5, in the initial state, electrons (qubits) are not confined in the quantum dots D12, D22, and D32 of the storage area A1 of the qubit array 100A, but electrons (qubits) are confined in the quantum dots D11-D31 and D13-D33 of the storage area A1. Thus, the qubit array 100A includes empty quantum dots D12, D22, and D32 in the storage area A1 that do not contain qubits. Furthermore, in the qubit array 100A, empty quantum dots that do not contain electrons (qubits) are arranged around the quantum dots that store electrons (qubits).

[0046] As a result, the control device 200 can easily move electrons confined in quantum dots D11-D31 and D13-D33 to empty quantum dots D12, D22, and D32 that do not contain electrons, and further move them to the movement area A3 and operation area A2 located outside the storage area A1, as shown below.

[0047] The control device 200 moves electrons (qubits) stored in storage area A1 to operation area A2 using a shuttle operation that moves electrons (qubits) by Coulomb force generated using multiple gate electrodes, and further performs a quantum gate operation in operation area A2 to change the electron spin state of the electrons (qubits).

[0048] A shuttle operation is an operation that moves an electron (qubit) by changing the potential around the quantum dot from which it originates, thereby using the Coulomb force to move the electron (qubit). Shuttle movement, on the other hand, is the movement of an electron (qubit) from one quantum dot to another due to the Coulomb force. In a shuttle operation, only the application of voltage to multiple gate electrodes is required. Therefore, compared to many other gate operations, shuttle operations can move electrons (qubits) at high speed and with high fidelity.

[0049] The control device 200 can perform quantum gate operations on electrons moved to the operation region A2 by shuttle operation, such as rotation gate operations that change the phase of the electron's spin, or controlled NOT gate operations, in the operation region A2, thereby changing the spin state of the electron.

[0050] Figure 6 illustrates the operation of a controlled NOT gate to change the spin state of two electrons moved to the operation region A2. Figure 6 shows a circuit diagram of the state in which the electrons confined in quantum dots D23 and D33, respectively, in the initial state shown in Figure 5, have been moved to quantum dots D53 and D63 by shuttle operation. In the circuit diagram of Figure 6, voltages with potentials different from the steady state are applied to the gate electrodes XQ5, XJ5, and XQ6 on the +Z side of quantum dots D23 and D33 to induce an exchange interaction between electrons e23 and e33 confined in quantum dots D53 and D63. Furthermore, the control device 200 applies an electromagnetic wave pulse (RF pulse) at the resonance frequency of electrons e23 and e33 confined in quantum dots D53 and D63 to rotate the electron spins of electrons e23 and e33 and perform the controlled NOT gate operation.

[0051] The control device 200 then outputs the electrons e23 and e33 after the controlled NOT gate operation to the measuring device 300 via terminal Out1 of section X 112x1 of the calculation area 112. The measuring device 300 then measures the state of the electrons (qubits), such as the number of electrons (qubits), related to the electrons e23 and e33, and outputs the measurement results to the control device 200. The state of the electrons (qubits) measured by the measuring device 300 is the result of the quantum operation.

[0052] Here, when applying quantum gate operations such as exchange interactions that change the state of electron spin (spin) to electrons (qubits) present in operating region A2, the electrons (qubits; e23, e33 in Figure 7D; e33, e31 in Figure 8G; e21, e31, e23, e33 in Figure 9E) present in operating region A2 are placed in the static magnetic field of magnet 140. Due to the Zeeman effect, the energy difference between the excited state and the ground state of the electrons (qubits) present in operating region A2, as well as the resonance frequency, can be increased in proportion to the strength of this static magnetic field.

[0053] On the other hand, the electrons (qubits, such as electrons e11 and e31) present in storage region A1 and the electrons (qubits) present in mobile region A3 are shielded by the magnetic shield 150 from the magnet 140, thus suppressing an increase in the resonance frequency due to the static magnetic field of the magnet 140.

[0054] Thus, the difference between the resonance frequency of electrons (qubits) in the operating region A2 and the resonance frequencies of electrons (qubits) in the storage region A1 and mobile region A3 increases depending on the position of the magnet 140 and the magnetic shield 150. The rotation of the electron's spin occurs when the electron is exposed to electromagnetic waves at the resonance frequency. Therefore, due to the difference between the resonance frequency of electrons (qubits) in the storage region A1 and mobile region A3 and the resonance frequency of electrons (qubits) in the operating region A2, even when an electromagnetic wave pulse (RF pulse) at the resonance frequency of the electrons (qubits) in the operating region A2 is applied, the rotation of the electron spin (spin) of electrons (qubits) in the storage region A1 and mobile region A3 is suppressed.

[0055] Therefore, the quantum information processing system 1 can suppress disturbances in the electron spin (spin) state of electrons (qubits) in storage region A1 and mobile region A3 by performing quantum gate operations that change the spin state of electrons (qubits) in operation region A2.

[0056] The quantum information processing system 1 may omit the magnet 140 and the magnetic shield 150. Instead of using the magnet 140, the quantum information processing system 1 applies a voltage of a predetermined potential from a gate electrode or the like onto the quantum dots in the operation region A2 where electrons (qubits) are confined. This increases the energy difference between the excited state and the ground state of the electrons (qubits) in the operation region A2 due to the Stark effect, thereby increasing the resonance frequency.

[0057] Furthermore, the quantum information processing system 1 applies a quantum gate operation to the electrons (qubits) e23 and e33 that are the target of the quantum gate operation and are located in the operation region A2, when the distance between the electrons (qubits) e11-e13, e21-e23, and e13 located in the storage region A1 surrounding the qubits that are the target of the quantum gate operation and are located in the operation region A2 is greater than a predetermined distance that can suppress the disturbance of the spin state caused by the quantum gate operation when the quantum gate operation is applied to the electrons (qubits) e23 and e33 that are the target of the quantum gate operation and are located in the operation region A2. As a result, the quantum information processing system 1 can suppress the loss of coherence of electrons (qubits) e11-e13, e21-e23, and e13 that exist in storage region A1 surrounding electrons (qubits) e23 and e33 that are the targets of quantum gate operations. In other words, the quantum information processing system 1 can perform quantum operations while suppressing disturbances in the electron spin (spin) state of the electrons (qubits).

[0058] <<Examples of operations performed by Quantum Information Processing System 1 (Figures 5, 7A-9E)>> The following describes an example of quantum computation in the quantum information processing system 1. In computation example 1, the control device 200, in the initial state shown in Figure 5, moves electrons e23 and e33 confined in quantum dots D23 and D33 in storage area A1 to quantum dots D53 and D63 in operation area A2 by shuttle operation, and then performs a controlled NOT gate operation on quantum dots D53 and D63.

[0059] Calculation example 2 is a case in which a controlled NOT gate operation is performed on electron e33 confined in quantum dot D33 in the X section 112x3 of calculation region 112 and on electron e33 confined in quantum dot D31 in the X section 112x1 of calculation region 112.

[0060] Calculation example 3 is a case in which the operation of controlled NOT gates on electrons e23 and e33 confined in quantum dots D23 and D33 in the X section 112x3 of calculation region 112 and the operation of controlled NOT gates on electrons e21 and e31 confined in quantum dots D21 and D31 in the X section 112x1 of calculation region 112 are performed in parallel.

[0061] <Calculation Example 1 (Figures 7A-7E)> Calculation Example 1 is a case in which the control device 200, in the initial state shown in Figure 5, moves electrons e23 and e33 confined in quantum dots D23 and D33 in storage area A1 to quantum dots D53 and D63 in operation area A2 by shuttle operation, and then performs a controlled NOT gate operation on quantum dots D53 and D63.

[0062] Figures 7A-7E are circuit diagrams of the quantum computing device 100 during the processing of Calculation Example 1.

[0063] As shown in Figure 7A, in calculation example 1, the control device 200 moves the electron e33 confined in quantum dot D33 in storage region A1 from quantum dot D33 to quantum dot Dy3 in mobile region A3 by shuttle operation, setting the voltages of gate electrodes XQ3, XJ3, and YQ3 to a predetermined potential.

[0064] Electrons have a negative charge. In shuttle operations, the potential of the gate electrode on the quantum dot is set to (1)-(3) below so that electrons move by Coulomb force. (1) The potential of the gate electrode located above the source quantum dot D is lowered to facilitate the movement of electrons (qubits) confined in the source quantum dot D. (2) The potential of the gate electrode located on quantum dot B, which is part of the potential barrier on the destination side of quantum dot D, is increased so that the electron (qubit) confined in the source quantum dot D can move across the potential barrier quantum dot B to the destination quantum dot D. (3) The potential of the gate electrode on the destination quantum dot D is increased so that the electron (qubit) confined in the source quantum dot D is attracted to the destination quantum dot D by the Coulomb force.

[0065] In the example shown in Figure 7A, the shuttle operation is performed by setting the gate electrode to (7A1)-(7A3) as follows. (7A1) The potential of the gate electrode XQ3 located on the source quantum dot D33 is lowered to facilitate the movement of the electron (qubit) e33 confined in the source quantum dot D33. (7A2) The potential of gate electrode XJ3, which is located on the potential barrier quantum dot B33 on the destination side of quantum dot D33, is increased so that the electron (qubit) e33 confined in the source quantum dot D33 can move across the potential barrier quantum dot B33 to the destination quantum dot Dy3. (7A3) The potential of the gate electrode YQ3 located on the destination quantum dot Dy3 is increased so that the electron (qubit) e33 confined in the source quantum dot D33 is attracted to the destination quantum dot Dy3 by the Coulomb force.

[0066] Next, as shown in Figure 7B, the control device 200 (7B1) moves the electron e23 confined in quantum dot D23 in storage area A1 from quantum dot D23 to quantum dot D33 by shuttle operation, and (7B2) moves the electron e33 that has been moved to quantum dot Dy3 in movement area A3 from quantum dot Dy3 in movement area A3 to quantum dot D53 in operation area A2 by shuttle operation.

[0067] Here, as a shuttle operation, the control device 200 applies voltages so that gate electrodes XQ2, XJ2, and XQ3 reach predetermined potentials in order to move electron e23 from quantum dot D23 to quantum dot D33 (7B1). Simultaneously, the control device 200 applies voltages so that gate electrodes YQ3, XJ4, and XQ5 reach predetermined potentials in order to move electron e33 from quantum dot Dy3 to quantum dot D53 (7B2). More specifically, the control device 200 lowers the potential of gate electrode XQ2, raises the potential of gate electrode XJ2, raises the potential of gate electrode XQ3, lowers the potential of gate electrode YQ3, raises the potential of gate electrode XJ4, and raises the potential of gate electrode XQ5. Here, since the protrusion Ya of gate electrode YQ3 is on quantum dot Dy3, the source of electron e33's movement, the control device 200 lowers the potential of gate electrode YQ3.

[0068] Next, as shown in Figure 7C, the control device 200 moves the electron e23 confined in quantum dot D33 (7C1) from quantum dot D23 to quantum dot Dy3 by shuttle operation, and moves the electron e33 that was moved to quantum dot D53 (7B2) from quantum dot D53 to quantum dot D63 by shuttle operation.

[0069] Here, as a shuttle operation, the control device 200 applies voltages so that the gate electrodes XQ3, XJ3, and YQ3 reach predetermined potentials in order to move electron e23 of (7C1) from quantum dot D33 to quantum dot Dy3. Simultaneously, the control device 200 applies voltages so that the gate electrodes XQ5, XJ5, and XQ6 reach predetermined potentials in order to move electron e33 of (7C2) from quantum dot D53 to quantum dot D63. More specifically, the control device 200 lowers the potential of gate electrode XQ3, raises the potential of gate electrode XJ3, raises the potential of gate electrode YQ3, lowers the potential of gate electrode YQ5, raises the potential of gate electrode XJ5, and raises the potential of gate electrode XQ6.

[0070] Next, as shown in Figure 7D, the control device 200 moves the electron e23 that has been moved to quantum dot Dy3 from quantum dot Dy3 to quantum dot D53 using a shuttle operation.

[0071] Here, the control device 200 applies voltages to gate electrodes YQ3, XJ4, and XQ5 so that they reach predetermined potentials in order to move electron e23 from quantum dot Dy3 to quantum dot D53 as a shuttle operation. More specifically, the control device 200 lowers the potential of gate electrode YQ3, raises the potential of gate electrode XJ4, and raises the potential of gate electrode XQ5.

[0072] In the above, electrons e23 and e33, which were confined in quantum dots D23 and D33 in storage region A1, were moved to quantum dots D53 and D63 in operation region A2 by shuttle operation. As shown in Figure 7E, the controlled NOT gate operation described using Figure 5 can be performed on electrons e23 and e33 that have been moved to quantum dots D53 and D63.

[0073] Then, as explained using Figure 5, the control device 200 performs a controlled NOT gate operation on the electrons e23 and e33 that have been moved to the quantum dots D53 and D63.

[0074] Finally, the control device 200 outputs the electrons e23 and e33 after the controlled NOT gate operation from terminal Out3 of section X 112x3 of the calculation area 112 to the measuring device 300. The measuring device 300 then measures the state of the electrons (qubits), such as the number of electrons (qubits), related to the electrons e23 and e33, and outputs the measurement results to the control device 200. The state of the electrons (qubits) measured by the measuring device 300 is the result of the quantum operation.

[0075] <Calculation Example 2 (Figures 8A-8G)> The above example of calculation 1 is a case where a controlled NOT gate operation is performed on electrons e23 and e33 confined in quantum dots D23 and D33 in the X section 112x3 of the calculation region 112. In contrast, example of calculation 2 is a case where a controlled NOT gate operation is performed on electron e33 confined in quantum dot D33 in the X section 112x3 of the calculation region 112 and on electron e33 confined in quantum dot D31 in the X section 112x1 of the calculation region 112.

[0076] Figures 8A-8G are circuit diagrams of the quantum computing device 100 during the processing of Calculation Example 2.

[0077] As shown in Figure 8A, in calculation example 2, the control device 200 moves the electron e31 confined in quantum dot D31 in storage region A1 to quantum dot Dy1 in mobile region A3 by shuttle operation, starting from the initial state shown in Figure 5.

[0078] Here, the control device 200 applies voltages to gate electrodes XQ3, XJ3, and YQ1 as a shuttle operation, lowering the potential of gate electrode XQ3, raising the potential of gate electrode XJ3, and raising the potential of gate electrode YQ1.

[0079] Next, as shown in Figure 8B, the control device 200 moves the electrons e31 that have been moved to quantum dot Dy1 from quantum dot Dy1 to quantum dot Dy2 using a shuttle operation. Here, as a shuttle operation, the control device 200 applies voltages to gate electrodes YQ1, YJ1, and YQ2 to lower the potential of gate electrode YQ1, raise the potential of gate electrode YJ1, and raise the potential of gate electrode YQ2.

[0080] Next, as shown in Figure 8C, the control device 200 moves the electron e31 that has been moved to quantum dot Dy2 from quantum dot Dy2 to quantum dot Dy3 using a shuttle operation. Here, as a shuttle operation, the control device 200 applies voltages to gate electrodes XQ2, YJ2, and YQ3 to lower the potential of gate electrode YQ2, raise the potential of gate electrode YJ2, and raise the potential of gate electrode YQ3.

[0081] Next, as shown in Figure 8D, the control device 200 moves the electron e31 that has been moved to quantum dot Dy3 from quantum dot Dy3 to quantum dot D53 in operation region A2 using a shuttle operation. Here, as a shuttle operation, the control device 200 applies voltages to gate electrodes YQ3, XJ4, and XQ5 to lower the potential of gate electrode YQ3, raise the potential of gate electrode XJ4, and raise the potential of gate electrode XQ5.

[0082] Next, as shown in Figure 8E, the control device 200 moves the electron e31 that was moved to quantum dot D53 (8E1) from quantum dot D53 to quantum dot D63 using a shuttle operation. At the same time, the control device 200 moves the electron e33 that is confined in quantum dot D33 in storage area A1 (8E2) from quantum dot D33 to quantum dot Dy3 in moving area A3 using a shuttle operation.

[0083] Here, as a shuttle operation, the control device 200 applies voltages to gate electrodes XQ5, XJ5, and XQ6 to lower the potential of gate electrode XQ5, raise the potential of gate electrode XJ5, and raise the potential of gate electrode XQ6. Also, as a shuttle operation, the control device 200 applies voltages to gate electrodes XQ3, XJ3, and YQ3 to lower the potential of gate electrode XQ3, raise the potential of gate electrode XJ3, and raise the potential of gate electrode YQ3.

[0084] Next, as shown in Figure 8F, the control device 200 moves the electron e33 that has been moved to quantum dot Dy3 from quantum dot Dy3 to quantum dot D53 in operation region A2 using a shuttle operation. Here, as a shuttle operation, the control device 200 applies voltages to gate electrodes YQ3, XJ4, and XQ5 to lower the potential of gate electrode YQ3, raise the potential of gate electrode XJ4, and raise the potential of gate electrode XQ5.

[0085] In the above, electrons e31 and e33, which were confined in quantum dots D31 and D33 in storage area A1, were moved to quantum dots D63 and D53 in operation area A2 by shuttle operation. As shown in Figure 8G, the controlled NOT gate operation described using Figure 5 can be performed on electrons e31 and e33 that have been moved to quantum dots D63 and D53.

[0086] Then, as explained using Figure 5, the control device 200 performs a controlled NOT gate operation on the electrons e31 and e33 that have been moved to the quantum dots D63 and D53.

[0087] Finally, the control device 200 outputs the electrons e31 and e33 after the controlled NOT gate operation from terminal Out3 of section X 112x3 of the calculation area 112 to the measuring device 300. The measuring device 300 then measures the state of the electrons (qubits), such as the number of electrons (qubits), related to the electrons e31 and e33, and outputs the measurement results to the control device 200. The state of the electrons (qubits) measured by the measuring device 300 is the result of the quantum operation.

[0088] <Calculation Example 3 (Figures 9A-9E)> The above examples 1 and 2 show the operation of controlled NOT gates on two electrons e. In contrast, example 3 shows the operation of controlled NOT gates on electrons e23 and e33 confined in quantum dots D23 and D33 in the X section 112x3 of the calculation region 112, and on electrons e21 and e31 confined in quantum dots D21 and D31 in the X section 112x1 of the calculation region 112, performed in parallel.

[0089] Figures 9A-9E are circuit diagrams of the quantum computing device 100 during the processing of Calculation Example 3.

[0090] As shown in Figure 9A, in calculation example 3, the control device 200 moves the electron e31 confined in quantum dot D31 in storage area A1 to quantum dot Dy1 in mobile area A3 by shuttle operation, starting from the initial state shown in Figure 5 (9A1). At the same time, the control device 200 moves the electron e33 confined in quantum dot D33 in storage area A1 to quantum dot Dy3 in mobile area A3 by shuttle operation, starting from quantum dot D31 in storage area A1 (9A2).

[0091] Here, the control device 200 applies voltages to gate electrodes XQ2, XJ3, YQ1, and YQ3 as a shuttle operation, thereby lowering the potential of gate electrode XQ2, raising the potential of gate electrode XJ3, and raising the potentials of gate electrodes YQ1 and YQ3.

[0092] Next, as shown in Figure 9B, the control device 200 moves the electron e31 that was moved to quantum dot Dy1 (9B1) from quantum dot Dy1 to quantum dot D51 in operation region A2 using a shuttle operation. At the same time, the control device 200 moves the electron e21 that is confined in quantum dot D21 in storage region A1 (9B2) from quantum dot D21 to quantum dot D31 using a shuttle operation.

[0093] At the same time, the control device 200 moves the electron e33 that was moved to quantum dot Dy3 (9B3) from quantum dot Dy3 to quantum dot D53 in operation area A2 using a shuttle operation. At the same time, the control device 200 also moves the electron e23 that is confined in quantum dot D23 in storage area A1 (9B4) from quantum dot D23 to quantum dot D33 using a shuttle operation.

[0094] Here, the control device 200 applies voltages to gate electrodes YQ1, YQ3, XJ4, and XQ5 as shuttle operations (9B1) and (9B3) to lower the potentials of gate electrodes YQ1 and YQ3, raise the potential of gate electrode XJ4, and raise the potential of gate electrode XQ5.

[0095] Simultaneously, the control device 200 applies voltages to gate electrodes XQ2, XJ2, and XQ3 as shuttle operations (9B2) and (9B4) to lower the potential of gate electrode XQ2, raise the potential of gate electrode XJ2, and raise the potential of gate electrode XQ3.

[0096] Next, as shown in Figure 9C, the control device 200 moves the electron e31 that was moved to quantum dot D51 (9C1) from quantum dot D51 to quantum dot D61 using a shuttle operation. At the same time, the control device 200 moves the electron e21 that was moved to quantum dot D31 (9C2) from quantum dot D31 in storage area A1 to quantum dot Dy1 in moving area A3 using a shuttle operation.

[0097] At the same time, the control device 200 moves the electron e33, which was moved to (9C3) quantum dot D53, from quantum dot D53 to quantum dot D63 using a shuttle operation. Simultaneously, the control device 200 moves the electron e23, which was moved to (9C4) quantum dot D33, from quantum dot D33 in storage area A1 to quantum dot Dy3 in moving area A3 using a shuttle operation.

[0098] Here, the control device 200 applies voltages to the gate electrodes XQ5, XJ5, and XQ6 as shuttle operations of (9C1) and (9C3) to lower the potential of gate electrode XQ5, raise the potential of gate electrode XJ5, and raise the potential of gate electrode XQ6.

[0099] Simultaneously, the control device 200 applies voltages to gate electrodes XQ3, XJ3, YQ1, and YQ3 as shuttle operations of (9C2) and (9C4) to lower the potential of gate electrode XQ3, raise the potential of gate electrode XJ3, and raise the potentials of gate electrodes YQ1 and YQ3.

[0100] Next, as shown in Figure 9D, the control device 200 moves the electron e21 that was moved to quantum dot Dy1 (9D1) from quantum dot Dy1 in movement region A3 to quantum dot D51 in operation region A2 using a shuttle operation. At the same time, the control device 200 moves the electron e23 that was moved to quantum dot Dy3 (9D2) from quantum dot Dy3 in movement region A3 to quantum dot D53 in operation region A2 using a shuttle operation.

[0101] Here, the control device 200 applies voltages to gate electrodes YQ1, YQ3, XJ4, and XQ5 as shuttle operations (9D1) and (9D2) to lower the potentials of gate electrodes YQ1 and YQ3, raise the potential of gate electrode XJ4, and raise the potential of gate electrode XQ5.

[0102] In the above, electrons e21, e31, e23, and e33 confined in quantum dots D21, D31, D23, and D33 in storage region A1 were moved by shuttle operation to quantum dots D51, D61, D53, and D63 in operation region A2. As shown in Figure 9E, the controlled NOT gate operation described using Figure 5 can be performed on the electrons e21, e31, e23, and e33 moved to quantum dots D51, D61, D53, and D63.

[0103] Then, as explained with reference to Figure 5, the control device 200 performs a controlled NOT gate operation on electrons e21 and e31 that have been moved to quantum dots D51 and D61. Simultaneously, as explained with reference to Figure 5, the control device 200 performs a controlled NOT gate operation on electrons e23 and e33 that have been moved to quantum dots D53 and D63.

[0104] Finally, the control device 200 outputs the electrons e21 and e31 after the controlled NOT gate operation from terminal Out1 of section X 112x1 of the calculation area 112 to the measuring device 300, causing the measuring device 300 to measure the state of the electrons (qubits), such as the number of electrons (qubits), related to the electrons e21 and e31, and output the measurement results to the control device 200.

[0105] Furthermore, the control device 200 outputs the electrons e23 and e33 after the controlled NOT gate operation from terminal Out3 of section X 112x3 of the calculation area 112 to the measuring device 300, causing the measuring device 300 to measure the state of the electrons (qubits), such as the number of electrons (qubits), related to the electrons e23 and e33, and output the measurement results to the control device 200.

[0106] The state of the electron (qubit) measured by the measuring device 300 is the result of a quantum computation.

[0107] <Effects of the invention> As explained above, the quantum information processing system 1 moves electrons (qubits) stored in storage area A1 from storage area A1 to operation area A2 using shuttle operations, and then performs quantum gate operations in operation area A2 to change the spin state of the qubits.

[0108] Here, the operation performed by the quantum information processing system 1 to move the electron (qubit) to be subjected to a quantum gate operation from storage area A1 to operation area A2 is a shuttle operation, which moves the electron (qubit) using the Coulomb force generated by the gate electrodes XJ and XQ of the first gate electrode layer 120 and the gate electrodes YJ and YQ (multiple gate electrodes) of the second gate electrode layer 130. Compared to many other gate operations, the shuttle operation can move electrons (qubits) at high speed and with high fidelity. As a result, the quantum information processing system 1 can perform quantum operations using electrons (qubits) at a faster speed.

[0109] Furthermore, by using shuttle operations, when the quantum information processing system 1 moves the electron (qubit) that is the target of the quantum gate operation from storage area A1 to operation area A2, it is possible to suppress disturbances in the electron spin (spin) state of the electron (quantum) that is the target of the quantum gate operation and the electron (qubit) that is not the target of the quantum gate operation.

[0110] Furthermore, quantum gate operations that change the spin state of qubits are performed in the operation region A2, which is outside the storage region A1. Electrons (qubits) that are not the target of quantum gate operations are stored in storage region A1, away from the operation region A2 where the quantum gate operations are performed. As a result, the quantum information processing system 1 can suppress the disruption of the electron spin (spin) state of electrons (qubits) stored in storage region A1 that are not the target of quantum gate operations, due to quantum gate operations.

[0111] Therefore, the quantum information processing system 1 can suppress disturbances in the electron spin state by performing transfer operations on electrons (qubits) and quantum gate operations on electrons (qubits). In other words, the quantum information processing system 1 can perform quantum operations while suppressing disturbances in the electron spin state of electrons (qubits).

[0112] Furthermore, the quantum information processing system 1 suppresses the loss of coherence of qubits, enabling faster manipulation of qubits and making large-scale calculations easier to perform.

[0113] Furthermore, the quantum computing device 100 (qubit array 100A) has a movement region A3, which has quantum dots used for moving electrons (qubits), between the storage region A1 and the operation region A2. This ensures that the distance between the movement region A3 and the storage region A1 is reliably increased. As a result, the quantum information processing system 1 can more reliably suppress the disturbance of the electron spin (spin) state of electrons (qubits) stored in the storage region A1 that are not the target of quantum gate operations, due to quantum gate operations.

[0114] Furthermore, by moving the electrons (qubits) that are the target of the quantum gate operation in a movement region A3 located outside of storage region A1 where electrons (qubits) that are not the target of the quantum gate operation are stored, it is possible to more reliably suppress the disruption of the electron spin state caused by the movement of the electrons (qubits) that are the target of the quantum gate operation to the electrons (qubits) that are not the target of the quantum gate operation stored in storage region A1.

[0115] Furthermore, since the mobile region A3 contains empty quantum dots that do not contain electrons (qubits), the quantum information processing system 1 can reliably move electrons (qubits) within the mobile region A3.

[0116] Furthermore, storage region A1 includes empty quantum dots that do not contain electrons (qubits). This allows the quantum information processing system 1 to move an electron (qubit) at any position in storage region A1 from the inside to the outside operation region A2, and then perform a quantum gate operation within operation region A2 to change its spin state.

[0117] Therefore, the quantum information processing system 1 can realize fully connected quantum operations. Fully connected means that quantum gate operations can be performed between any two or more qubits out of all the qubits.

[0118] Furthermore, storage region A1 has empty quantum dots surrounding the quantum dots that confine electrons (qubits), where electrons (qubits) are not confined. This makes it easy for the quantum information processing system 1 to move electrons (qubits) present in storage region A1 to any location within storage region A1. In addition, it makes it easy for the quantum information processing system 1 to move electrons (qubits) present in storage region A1 to the operation region A2 located outside of storage region A1. Therefore, the quantum information processing system 1 can perform quantum operations more reliably. Moreover, the quantum information processing system 1 can perform quantum operations at a faster speed.

[0119] Furthermore, in the process of moving electrons (qubits) stored in storage area A1 from storage area A1 to operation area A2, the quantum information processing system 1 performs an operation to move two or more qubits stored in storage area A1 simultaneously (see Figures 7B, 7C, 8E, and 9A-9E). This allows the quantum information processing system 1 to perform quantum operations at a faster speed.

[0120] <Example 1> In the above-described examples 1-3, the quantum computing device 100 of the quantum information processing system 1 does not confine electrons (qubits) to the quantum dots of the X section 112x2 of the computing region 112. In the modified example 1, the computing region 112 omits the X section 112x2 and is formed by the X section 112x1, the X section 112x3, and the Y section 112y1.

[0121] <Modification 2> In the above-described examples 1-3, the quantum computing device 100 of the quantum information processing system 1 does not confine electrons (qubits) to the quantum dots of the X section 112x2 of the computation area 112 in its initial state. In the modified example 2, the quantum computing device 100 of the quantum information processing system 1 confines electrons (qubits) to the quantum dots of the X section 112x2 of the computation area 112 in its initial state.

[0122] <Modification Example 3 (Figure 10)> The quantum information processing system 1 of this embodiment has a qubit array 100A with one storage area A1, one operation area A2, and one movement area A3. The size, shape, and arrangement of the storage area A1, operation area A2, and movement area A3 can be freely changed.

[0123] Figure 10 shows an example of the arrangement of the storage area A1, operation area A2, and movement area A3 in the qubit array 100A of the quantum information processing system 1 of Modification 3. In the qubit array 100A of Figure 10, the movement area A3 is provided around the storage area A1 and the operation area A2. This makes it easy to move electrons (qubits) stored in the storage area A1 to the operation area A2.

[0124] <Example 4 (Figure 11)> Figure 11 shows an example of the arrangement of the storage area A1, operation area A2, and movement area A3 in the qubit array 100A of the quantum information processing system 1 of Modification 4.

[0125] In the modified example 4 of the quantum information processing system 1, the qubit array 100A is surrounded by a movement region A3 around the storage region A1, as shown in Figure 11, and the corners of the storage region A1 are in contact with the operation region A2. As a result, since the movement region A3 adjacent to the operation region A2 contains two storage regions A1, it becomes easy to move electrons (qubits) stored in the storage region A1 to the operation region A2.

[0126] <Modified example 5 (Figure 12)> Figure 12 shows an example of the arrangement of the storage area A1, operation area A2, and movement area A3 in the qubit array 100A of the quantum information processing system 1 of Modification 5.

[0127] In the modified example 5, the quantum information processing system 1's qubit array 100A has two storage regions A1 flanked by two movement regions A3 and one operation region A2, as shown in Figure 12. This makes it easy to move electrons (qubits) stored in storage region A1 to operation region A2.

[0128] <Modification example 6 (Figure 13)> Figure 13 shows an example of the arrangement of storage area A1 and operation area A2 in the qubit array 100A of the quantum information processing system 1 of Modification 6.

[0129] In the quantum information processing system 1 of Modified Example 6, as shown in Figure 13, the qubit array 100A has two storage areas A1 with one operation area A2 sandwiched in between. Here, the operation area A2 also serves as the movement area A3 and has quantum dots used for moving electrons (qubits). However, the qubit array 100A of Modified Example 6 does not have a movement area A3. The configuration of the qubit array 100A of Modified Example 6 makes it easy to move electrons (qubits) stored in the storage area A1 to the operation area A2.

[0130] <Modified example 7 (Figure 14)> Figure 14 shows an example of the arrangement of storage area A1 and operation area A2 in the qubit array 100A of the quantum information processing system 1 of Modification 7.

[0131] In the quantum information processing system 1 of Modification 7, the qubit array 100A has one operation area A2 within one storage area A1, as shown in Figure 14. Here, the operation area A2 also serves as the movement area A3 and has quantum dots used for the movement of electrons (qubits). In contrast, the qubit array 100A of Modification 6 does not have a movement area A3.

[0132] The configuration of the qubit array 100A in Modification 7 makes it easy to move electrons (qubits) stored in storage area A1 to operation area A2. Furthermore, the presence of storage area A1 surrounding operation area A2 makes it easy to perform quantum gate operations that change the spin state of many electrons (qubits) in a single operation area A2.

[0133] It should be noted that the present invention is not limited to the embodiments and modifications described above, and various modifications are possible within the scope of its essence. [Explanation of symbols]

[0134] 1: Quantum Information Processing System 100: Quantum computing device 100A: Quantum bit array 110: Computation layer 111: Computation layer main body 112: Arithmetic area 112x1, 112x2, 112x3:X part 112y1:Y section Res1, Out1, Res2, Out2, Res3, Out3, Resy, Outy: Terminals D11-D61, D12-D62, D13-D63, Dy1-Dy3: Quantum dots B01-B61, B02-D62, B03-D63, By0-B03: Potential barriers 120: First gate electrode layer XJ0-XJ6, XJ, XQ1-XQ6, XQ: Gate terminal 130: Second gate electrode layer YJ0-YJ3, YJ, YQ1-YQ3, YQ: Gate Tube YJ3a, Ya: Protrusion 140: Magnet 150: Magnetic Shielding 200: Control device 210: Quantum bit processing unit 210a: Quantum bit processing program 211: Processor 212: Main memory 213: Secondary storage device 214: Input / Output Devices 215: Quantum operation device I / F 216: Bus 300: Measuring device

Claims

1. A quantum information processing system that performs quantum gate operations to change the spin state of multiple qubits, A control device that performs control over the plurality of qubits, A qubit array having a plurality of quantum dots capable of confining the qubit and a plurality of gate electrodes used to control the plurality of quantum dots, Equipped with, The aforementioned qubit array is A storage area having multiple quantum dots for storing the aforementioned qubits, The system has an operation region having a plurality of quantum dots to which the quantum gate operation that changes the spin state of the confined qubit can be applied, The control device is When the distance between the qubit targeted for the quantum gate operation, located in the operation area, and the qubits surrounding the qubit targeted for the quantum gate operation, located in the storage area, is greater than a predetermined distance that can suppress the disturbance of the spin state caused by the quantum gate operation when the quantum gate operation is applied to the qubit targeted for the quantum gate operation, the quantum gate operation is applied to the qubit targeted for the quantum gate operation. Quantum information processing system.

2. A quantum information processing system according to Claim 1, The control device controls the plurality of qubits confined in the qubit array using the plurality of gate electrodes, The control device is A shuttle operation is performed to move the qubit using the Coulomb force generated by the plurality of gate electrodes, moving the qubit stored in the storage area from the storage area to the operation area, and further performing the quantum gate operation in the operation area to change the spin state of the qubit. Quantum information processing system.

3. A quantum information processing system according to claim 2, The qubit array further has a movement region between the storage region and the operation region, which has a quantum dot used for moving the qubits. Quantum information processing system.

4. A quantum information processing system according to claim 3, The moving region includes empty quantum dots that do not contain the qubits. Quantum information processing system.

5. A quantum information processing system according to claim 3, Furthermore, it includes a magnet provided around the operating area, and a magnetic shield that shields the magnetic force of the magnet from the storage area and the moving area. Quantum information processing system.

6. A quantum information processing system according to claim 2, The storage area includes empty quantum dots that do not contain the qubits, Quantum information processing system.

7. A quantum information processing system according to claim 6, The storage area has empty quantum dots around the quantum dots that confine the qubits. Quantum information processing system.

Images