Discrete multi-qubit system based on magnetic resonance, and quantum information processing method using same

Abstract

Disclosed is a qubit system based on magnetic resonance, according to some embodiments of the present disclosure. The qubit system may comprise: a magnet having a space provided on the inside thereof; a qubit sample which is disposed in the space provided on the inside of the magnet and contains a material capable of quantum state transition; a gradient coil which is disposed on the outside of the qubit sample to correspond to the qubit sample on the inside of the magnet and generates a gradient magnetic field in the space on the inside of the magnet, which has the qubit sample contained therein; an RF transmitting coil part disposed between the qubit sample and the gradient coil on the inside of the magnet, to apply radio frequency (RF) pulses to the qubit sample and control a quantum state of the qubit sample; and an RF receiving coil disposed on the inside of the magnet to receive RF signals emitted from the qubit sample due to the applied RF pulses.

Description

Magnetic resonance-based discrete multiple-qubit system and quantum information processing method using the same

[0001] The present disclosure relates to quantum information processing technology, and more specifically, to a magnetic resonance-based discrete multiple qubit system and a quantum information processing method using the same.

[0002] Quantum information processing technology is a core foundational technology utilized in new digital technologies such as quantum computing, quantum cryptography, and quantum sensors. Quantum computers can be used for quantum information processing, which processes data by utilizing phenomena related to quantum mechanics.

[0003] Quantum computers can be computers that process data by exploiting phenomena related to quantum mechanics, such as quantum entanglement and quantum superposition. Quantum entanglement is a series of non-classical correlations that can exist between two subsystems even when they are spatially separated. Entanglement can mean that the states of the two subsystems are unknown until a measurement is made, but the moment a measurement is made, the state of one subsystem is determined, which immediately determines the state of the other entangled subsystem. Quantum superposition can mean that two or more quantum states can be added together, and the result is expressed as a linear sum of two or more distinct states, resulting in another quantum state. Furthermore, quantum computers can use quantum bits, or qubits, as the smallest basic unit of quantum information for processing data by exploiting phenomena related to quantum mechanics.

[0004] The information of a qubit is represented by two quantum states (or vectors) using the bra-ket notation |0> and |1>. A pure qubit state is a linear quantum superposition of these two states, and therefore, the state of any qubit can be expressed as a linear combination of |0> and |1>, as |Ψ>=α|0>+β|1>. Here, α and β are complex probability amplitudes and |α| 2 +|β| 2 =1. In this case, the probability that the corresponding qubit is measured in the |0> state is |α| 2 and the probability of being measured in the state |1> is |β| 2 Therefore, the total probability of being measured in these two states is 1. When a qubit is observed, the quantum superposition state is released and it can be determined to be in one state.

[0005] A system that implements operations for quantum information processing within the coherence time that maintains a quantum superposition state in various platform areas depending on the physical origin of the qubit can be collectively referred to as a 'qubit system'.

[0006] Existing qubit systems can be categorized into superconducting qubit systems, semiconductor quantum dot qubit systems, trapped ion qubit systems, quantum optics qubit systems, diamond nitrogen-vacancy (NV) center qubit systems, and Ryderberg qubit systems. Most existing qubit systems are known to use a method of generating each qubit with one (or two or three) particles, and it may be difficult to efficiently generate qubits due to problems such as preemptive requirements for ultra-low temperatures, high vacuum, and ultra-low vibration conditions, limited scalability for increasing the number of qubits, coherence times shorter than 1 ms, or significant quantum information errors.

[0007] In addition, the existing qubit system based on Nuclear Magnetic Resonance (NMR) spectroscopy analysis is based on a technology that analyzes the components of a substance (liquid or solid) composed of hydrogen, carbon, chlorine, etc., and uses phenomena such as J coupling and chemical shift between the constituent atoms of the substance inserted into a single container to create a qubit, which may limit the scalability of the qubit.

[0008] Furthermore, in magnetic resonance-based qubit systems, the strength of the magnetic field from the magnet directly affects the resonant frequency of the RF pulse that modifies the quantum state of the qubit spin. Therefore, uniformity is crucial, maintaining the same magnetic field strength from the magnet regardless of the location of each qubit sample and the external environment. In this regard, Republic of Korea Patent No. 10-2116277 (announced on May 29, 2020) has been issued.

[0009] The present disclosure is conceived in response to the aforementioned background technology, and aims to provide a magnetic resonance-based discrete multiple qubit system for quantum information processing and a quantum information processing method using the same.

[0010] The technical problems of the present disclosure are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0011] In order to solve the above-described problems, a magnetic resonance-based qubit system according to some embodiments of the present disclosure is disclosed. The qubit system may include a magnet having a space formed therein; a qubit sample provided in the space formed inside the magnet and including a material capable of quantum state transition; a gradient coil provided outside the qubit sample corresponding to the qubit sample inside the magnet and generating a gradient magnetic field in the space containing the qubit sample inside the magnet; an RF transmitting coil unit disposed between the qubit sample and the gradient coil inside the magnet and applying an RF pulse to the qubit sample and controlling a quantum state of the qubit sample; and an RF receiving coil provided inside the magnet and receiving an RF signal emitted after the RF pulse ends from the qubit sample that has absorbed energy due to the applied RF pulse.

[0012] Alternatively, when the number of qubit samples is plural, the plurality of qubit samples are arranged spaced apart from each other to correspond to predetermined positions inside the magnet, and the gradient coil, the RF transmitting coil unit, and the RF receiving coil are provided corresponding to each of the plurality of qubit samples, and one qubit sample may correspond to one gradient coil, one RF transmitting coil unit, and one RF receiving coil.

[0013] Alternatively, when there are multiple gradient coils, each of the multiple gradient coils is assigned a unique number identical to the qubit sample provided, and each of the multiple gradient coils can apply a discrete gradient field determined in correspondence to the unique number.

[0014] Alternatively, when there are multiple RF transmitting coil units, the multiple RF transmitting coil units can apply RF pulses having different resonance frequencies (Larmor frequencies) determined according to discrete gradient fields applied from each of the multiple gradient coils in response to the unique number.

[0015] Alternatively, when there are multiple RF transmitting coil units, the multiple RF transmitting coil units can change the state of the qubit generated from the qubit sample located inside each of the multiple RF transmitting coil units based on the applied RF pulse.

[0016] Alternatively, if there is a difference of a predetermined threshold value between the actual magnetic field applied by the magnet and a theoretically predetermined ideal magnetic field in the inner region of the gradient coil, the gradient coil may additionally apply a magnetic field of the threshold value for magnetic field shimming of the magnet.

[0017] Alternatively, the RF transmitting coil unit may include a first RF transmitting coil disposed in a first space between the qubit sample and the gradient coil within the magnet, and applying a first RF pulse (radio frequency pulse) to the magnet; a second RF transmitting coil disposed in a second space between the qubit sample and the gradient coil within the magnet, and applying a second RF pulse to the magnet; and a third RF transmitting coil disposed in a third space between the qubit sample and the gradient coil within the magnet, and applying a third RF pulse to the magnet.

[0018] Alternatively, the first RF transmitting coil can apply the first RF pulse corresponding to the qubit sample to the internal space containing the qubit sample in a direction perpendicular to the magnetic field of the magnet.

[0019] Alternatively, the second RF transmitting coil can apply the second RF pulse corresponding to the qubit sample to the internal space containing the qubit sample in a direction perpendicular to the magnetic field of the magnet and the magnetic field applied by the first RF transmitting coil.

[0020] Alternatively, the third RF transmitting coil can apply the third RF pulse corresponding to the qubit sample to the internal space containing the qubit sample in a direction parallel to the magnetic field of the magnet.

[0021] Alternatively, if the second RF transmitting coil is not provided, the second RF pulse is identical to an RF pulse whose phase is 90 degrees different from the first RF pulse, so that an RF pulse identical to the second RF pulse corresponding to the qubit sample can be applied to the internal space containing the qubit sample using the first RF transmitting coil.

[0022] Alternatively, when the third RF transmitting coil is not provided, the first RF pulse and the second RF pulse can be combined to implement an RF pulse identical to the third RF pulse, so that the third RF pulse corresponding to the qubit sample can be applied to the internal space including the qubit sample by using the first RF transmitting coil and the second RF transmitting coil together or by using only the first RF transmitting coil.

[0023] Alternatively, if the RF receiving coil is not separately provided, a duplexer may be connected to the first RF transmitting coil to enable use for both transmitting and receiving.

[0024] A method for controlling a state of a qubit according to some embodiments of the present disclosure for solving the aforementioned problem may include the steps of: applying an RF pulse to a qubit sample provided inside a magnet by an RF transmitting coil unit disposed between a qubit sample provided inside a magnet and including a material capable of quantum state transition and a gradient coil provided inside the magnet corresponding to the qubit sample; and converting a state of a qubit in the qubit sample based on the applied RF pulse.

[0025] According to some embodiments of the present disclosure for solving the aforementioned problem, a quantum information processing method performed in a processor of a computing device comprises the steps of: initializing a qubit state using a qubit system; converting a state of the qubit by applying an RF pulse through an RF transmitting coil unit provided corresponding to each of a plurality of qubit samples; measuring the state of the converted qubit through an RF receiving coil provided corresponding to each of a plurality of qubit samples; and analyzing a result of measuring the state of the qubit; wherein the qubit system comprises: a magnet having a space formed therein; a qubit sample provided inside the magnet and including a material capable of quantum state transition; a gradient coil provided inside the magnet corresponding to the qubit sample and generating a gradient magnetic field inside the magnet; an RF transmitting coil unit disposed inside the magnet between the qubit sample and the gradient coil, applying an RF pulse inside the magnet and controlling the qubit state using the qubit sample; and an RF receiving coil provided inside the magnet and receiving an RF signal emitted after the RF pulse ends from the qubit sample that has absorbed energy due to the applied RF pulse.

[0026] Alternatively, the step of transforming the state of the qubit may include the step of transforming the state of the qubit using a series of RF pulses corresponding to rotation operators of a predetermined quantum gate.

[0027] Alternatively, the step of analyzing the result of measuring the state of the qubit may include the step of comparing the measured value included in the result with an expected value corresponding to a rotation operator of the predetermined quantum gate.

[0028] In accordance with the present disclosure for solving the aforementioned problems, based on the technology applied in diagnostic magnetic resonance imaging (MRI) devices that have been commercially developed and are widely used in hospitals, some of the MRI technologies are modified and supplemented so that they can be applied to the development of a quantum computing platform that can easily implement the above-mentioned discrete multi-qubit system, and new technologies are additionally developed and applied, thereby developing and integrating a unique technology that is differentiated from various existing qubit systems, has relatively low difficulty, and is easy to implement, thereby significantly shortening the period required for the development and commercialization of a magnetic resonance-based discrete multi-qubit system for quantum information processing.

[0029] When permanent magnets are used, the extremely difficult technologies required for various existing qubit systems, such as superconducting qubit systems, semiconductor quantum dot qubit systems, trapped ion qubit systems, quantum optics qubit systems, diamond nitrogen-vacancy center qubit systems, and Rydberg qubit systems, such as cryogenic temperatures, ultra-vacuum, nano-level semiconductor processes, lasers, and quantum optics, can be eliminated, and instead, technology that can operate at room temperature can be utilized, resulting in ease of development. In addition, when developing a multi-qubit module method containing 5 to 10 qubits using a small plate-shaped permanent magnet and applying a magnetic field and radio frequency shielding device, the number of qubits can be easily expanded by stacking 10 modules in each of the horizontal, vertical, and height directions in a three-dimensional space.

[0030] The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and other effects that are not mentioned will be clearly understood by a person having ordinary skill in the art to which the present disclosure pertains from the description below.

[0031] Various aspects are now described with reference to the drawings, wherein like reference numerals are used to refer to similar components generally. In the following examples, for purposes of explanation, numerous specific details are set forth to provide a comprehensive understanding of one or more aspects. However, it will be apparent that such aspects may be practiced without these specific details.

[0032] FIG. 1 is a diagram illustrating a qubit system according to some embodiments of the present disclosure.

[0033] FIG. 2A is a diagram illustrating a single qubit module of a qubit system according to some embodiments of the present disclosure, wherein the single qubit module includes a first RF transmitting (also receiving) coil, a second RF transmitting coil, and a third RF transmitting coil.

[0034] FIG. 2b is a diagram illustrating a case in which only a first RF transmitting (also receiving) coil is provided in a single qubit module of a qubit system according to some embodiments of the present disclosure.

[0035] FIG. 3 is a diagram showing a state in which a plurality of qubit modules are provided inside a magnet in a qubit system according to some embodiments of the present disclosure.

[0036] FIG. 4 is a diagram illustrating a control unit of a qubit system according to some embodiments of the present disclosure.

[0037] FIG. 5 is a diagram illustrating an RF signal shielding device of a qubit system according to some embodiments of the present disclosure.

[0038] FIG. 6 is a diagram illustrating a method for scaling up a qubit system according to some embodiments of the present disclosure.

[0039] FIG. 7 is a diagram illustrating a method for controlling the state of a qubit in a qubit system according to some embodiments of the present disclosure.

[0040] FIG. 8 is a diagram illustrating a quantum information processing method using a qubit system according to some embodiments of the present disclosure.

[0041] FIG. 9 illustrates a simplified, general schematic diagram of an exemplary computing environment in which embodiments of the present disclosure may be implemented.

[0042] Various embodiments are now described with reference to the drawings. In this specification, various descriptions are provided to facilitate understanding of the present disclosure. However, it will be apparent that these embodiments may be practiced without these specific details.

[0043] As used herein, the terms "component," "module," "system," and the like refer to computer-related entities, hardware, firmware, software, a combination of software and hardware, or an execution of software. For example, a component may be, but is not limited to, a procedure running on a processor, a processor, an object, a thread of execution, a program, and / or a computer. For example, both an application running on a computing device and the computing device may be a component. One or more components may reside within a processor and / or a thread of execution. A component may be localized within a single computer. A component may be distributed between two or more computers. Furthermore, these components may execute from various computer-readable media having various data structures stored therein. Components may communicate via local and / or remote processes, for example, by signals comprising one or more data packets (e.g., data from one component interacting with another component in a local system, a distributed system, and / or data transmitted to another system via a network such as the Internet via signals).

[0044] Furthermore, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or." That is, unless otherwise specified or clear from context, "X employs A or B" is intended to mean either of the natural inclusive permutations. That is, if X employs A; X employs B; or X employs both A and B, "X employs A or B" can apply to any of these cases. Furthermore, the term "and / or" as used herein should be understood to refer to and include all possible combinations of one or more of the associated items listed.

[0045] Additionally, the terms "comprises" and / or "comprising" should be understood to imply the presence of the features and / or components in question. However, it should be understood that the terms "comprises" and / or "comprising" do not exclude the presence or addition of one or more other features, components, and / or groups thereof. Furthermore, unless otherwise specified or clear from the context to refer to the singular form, the singular in the specification and claims should generally be construed to mean "one or more."

[0046] And, the term "at least one of A or B" should be interpreted to mean "if it includes only A", "if it includes only B", or "if it is combined in the composition of A and B".

[0047] Those skilled in the art should further appreciate that the various illustrative logical blocks, configurations, modules, circuits, means, logics, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate the interchangeability of hardware and software, various illustrative components, blocks, configurations, means, logics, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application. However, such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

[0048] The description of the disclosed embodiments is provided to enable a person skilled in the art to make or use the present disclosure. Various modifications to these embodiments will be apparent to those skilled in the art. The general principles defined herein may be applied to other embodiments without departing from the scope of the present disclosure. Thus, the present disclosure is not limited to the embodiments set forth herein. The present disclosure is to be construed in the widest scope consistent with the principles and novel features disclosed herein.

[0049] In the present disclosure, terms expressed as N, such as first, second, or third, are used to distinguish at least one entity. For example, entities expressed as first and second may be the same or different from each other.

[0050] In the present disclosure, terms expressed as NN, such as 1-1, 2-1, or 3-1, are used to distinguish at least one entity. For example, entities expressed as 1-1 and 1-2 may be the same or different from each other.

[0051] In the present disclosure, the computing device may include a quantum computer. A quantum computer may be a computer that processes data using phenomena related to quantum mechanics, such as quantum entanglement and quantum superposition.

[0052] Quantum entanglement is a set of non-classical correlations that can exist even when two subsystems are spatially separated from each other. It can mean that the states of the two subsystems are unknown until a measurement is made, but the moment a measurement is made, the state of one subsystem is determined, and this immediately determines the state of the other entangled subsystem.

[0053] Quantum superposition can mean that two or more quantum states can be added together, and the result is another quantum state expressed as a linear sum of two or more different, distinct states.

[0054] Additionally, quantum computers can use quantum bits, or qubits, as the smallest basic unit of quantum information to process data by exploiting phenomena related to quantum mechanics.

[0055] The qubit system in the present disclosure may include an actuation method for controlling a qubit state. As another example, the qubit system may include a device or structure for controlling a qubit state.

[0056] In the present disclosure, controlling a qubit state may mean applying an arbitrary RF pulse signal to the qubit sample through an RF transmission coil provided for each qubit sample, thereby controlling the state of the qubit sample to change appropriately according to the RF pulse signal.

[0057] In the present disclosure, a qubit system may include a qubit system based on magnetic resonance. For example, when a qubit sample made by putting water in a glass sphere is placed in a magnetic field by a magnet, the energy is determined differently depending on the direction of the magnetic moment of the hydrogen proton spin of the water constituting the qubit sample, and the hydrogen proton spin can perform precessional motion with a frequency proportional to the strength of the magnetic field by the magnet (42.59 MHz / T in the case of hydrogen) with the direction of the magnetic field by the magnet as the central axis. Magnetic resonance may mean that when an RF pulse signal having the same frequency as the frequency at which the hydrogen proton spin precesses, i.e., the Larmor frequency, is applied to the qubit sample, the hydrogen proton spin absorbs the energy of the RF pulse signal, thereby changing the state of the qubit sample.

[0058] FIG. 1 is a diagram illustrating a qubit system according to some embodiments of the present disclosure.

[0059] Referring to FIG. 1, a qubit system (100) may include a heating plate (110), a magnet (120), and / or a qubit module (130). The configuration of the qubit system illustrated in FIG. 1 is merely a simplified example. In one embodiment of the present disclosure, the qubit system (100) may include other configurations for controlling and measuring qubit states, and only some of the disclosed configurations may constitute the qubit system.

[0060] The heating plate (110) may be an object that is connected to a heater and generates heat. The heating plate (110) may be detachably and / or attachably attached to a magnet (120). The heating plate (110) may be provided in a form that contacts at least a portion of the magnet (120). For example, the heating plate (110) may be provided in a form that contacts a side flat surface of the magnet (120). As another example, the heating plate (110) may be provided in a form that surrounds the periphery of the magnet (120).

[0061] The heating plate (110) can control the temperature of the magnet (120) through a heater. For example, the heating plate (110) can control the temperature of the magnet (120) to a temperature that is higher than the maximum ambient temperature expected during the time the magnet (120) is operated at the location where the magnet (120) is installed, and to a constant temperature.

[0062] A magnet (120) may be an object that generates a magnetic field. For example, the magnet (120) may generate a magnetic field of a predetermined direction and strength inside.

[0063] The magnet (120) may be formed in a form in which a space is formed inside. For example, the magnet (120) may be formed in a form in which two planar magnets are arranged in parallel, and a space may be formed between the two planar magnets. For another example, the magnet (120) may be formed in a rectangular parallelepiped form, and a space may be formed in a direction perpendicular to the parallel planes of the two planar magnets (e.g., the z-axis direction). Accordingly, a plurality of qubit modules (130) may be provided inside the magnet (120).

[0064] The interior of the magnet (120) may contain air or be in a vacuum. However, the shape of the magnet is not limited thereto and may include various shapes.

[0065] The type of magnet (120) may include a permanent magnet, a superconducting magnet, a high-temperature superconducting magnet, etc. For example, the magnet may include a liquid helium-cooled ultra-low temperature (e.g., 4K absolute temperature, etc.) electromagnet, a nitrogen-cooled low temperature (e.g., -196 degrees Celsius, etc.) electromagnet, a permanent magnet of a neodymium magnetic material that operates at room temperature, etc. However, the type of the magnet (120) is not limited thereto, and may include various magnets that generate a magnetic field.

[0066] The magnetic flux density of the magnet (120) may be in the range of 0.5 T to 10 T. However, the magnetic flux density of the magnet (120) is not limited thereto and may include various magnetic flux densities. The magnet (120) may generate a magnetic field of a constant strength (e.g., 0.5 T, 1.0 T, 3.0 T, etc.) in a constant direction (e.g., +Z axis, etc.) within the qubit system.

[0067] Since the strength of the magnetic field by the magnet (120) directly affects the resonance frequency of the RF pulse that changes the quantum state of the spin of the material constituting the qubit sample, it is important to maintain the same magnetic field strength regardless of the location where all qubit samples are installed and the external environment.

[0068] However, it is known that all permanent magnets, including those made of neodymium, lose their magnetic performance at a rate determined by the size, shape, grade, and usage method of the magnet for every 1 degree Celsius increase in temperature. For example, it is known that neodymium permanent magnets lose 0.08% to 0.12% of their magnetic strength for every 1 degree Celsius increase in temperature. Therefore, in order to maintain a constant temperature of about 5 degrees Celsius higher than the maximum temperature expected at the time and place where a product using neodymium permanent magnets is operated, the qubit system (100) may additionally be equipped with a sensor for measuring the temperature of the neodymium permanent magnet, a heater, and a temperature control device.

[0069] Additionally, the qubit system (100) can perform a magnetic field correction operation so that the magnetic field strength remains constant regardless of the positions where multiple qubit samples are installed inside the magnet (120) (e.g., a permanent magnet). A method for correcting the magnetic field uniformity in the qubit system will be described later.

[0070] The qubit module (130) may be a module that is installed in a space formed inside a magnet (120) and generates a qubit. A detailed description of the qubit module (130) will be described later with reference to FIG. 2.

[0071] FIG. 2A is a diagram illustrating a case in which a single qubit module of a qubit system according to some embodiments of the present disclosure comprises a first RF transmit (also for receiving) coil, a second RF transmit coil, and a third RF transmit coil. FIG. 2B is a diagram illustrating a case in which a single qubit module of a qubit system according to some embodiments of the present disclosure comprises only a first RF transmit (also for receiving) coil.

[0072] Referring to FIG. 2A, the qubit module may include a qubit sample (210), a gradient coil (220), an RF transmitting coil unit (230), an RF receiving coil (not shown), etc. The configuration of the qubit module illustrated in FIG. 2A is merely a simplified example. In one embodiment of the present disclosure, the qubit module may include other configurations for generating qubits, and only some of the disclosed configurations may constitute the qubit module.

[0073] The qubit module is installed in a row or in an arbitrary shape on the XY plane perpendicular to the direction of the magnetic field by the magnet, and can be fixedly installed by rotating clockwise or counterclockwise at a predetermined angle (for example, 45 degrees) in the XY plane for each qubit. Therefore, the qubit module can minimize interference of RF signals between different qubits. In addition, when the qubit module is used for both transmitting RF pulses for spin control and receiving RF signals emitted by qubits through the RF transmitting coil in the X direction among the RF transmitting coil units (the magnetic field by the RF pulse is in the X, Y, and Z directions), the interference of the received signal can be minimized.

[0074] The qubit sample (210) may be a device, apparatus, material, etc. for generating a qubit. The qubit sample (210) may be provided inside the magnet (120) and may include a material (211) capable of quantum state transition. The material of the qubit sample (210) may be glass or reinforced plastic. The shape of the qubit sample (210) may be a sphere or tube with an empty interior. For example, when the qubit sample (210) is in the shape of a glass sphere, it may include a material (211) capable of state transition inside the glass sphere. However, the material and shape of the qubit sample (210) are not limited thereto, and may be various materials and shapes.

[0075] The qubit sample (210) can be placed in the internal space of the gradient magnetic field coil (220), RF transmitting coil unit (230), and / or RF receiving coil (not shown) installed exclusively for the qubit inside the magnet (120).

[0076] The substance (211) may include one of the properties of gas, liquid and / or solid.

[0077] The material (211) may include a nuclide having a 1 / 2 nuclear spin. The material (211) may include a hydrogen atomic nucleus ( 1 H) may be included. The material (211) is 13 C, 31 May include P, etc.

[0078] Nuclear spin can refer to any angular momentum of an atomic nucleus. Nuclear spin can be the combination of the spin and orbital angular momentum of any nucleon. Nucleons can be elementary particles that make up the nucleus. Nucleons can contain protons and / or neutrons.

[0079] A nuclide can be a nucleus or a type of atom, each with its own unique atomic number and mass number. The nucleus can be the positively charged central portion of an atom. An atom can refer to the fundamental particles that make up matter.

[0080] In one embodiment, a qubit sample can be manufactured by putting a material (e.g., distilled water) into a spherical or polygonal column-shaped device of a certain size with one end closed and sealing it with a non-magnetic stopper. The manufactured qubit sample can be fixedly installed inside an external cylindrical device (e.g., a glass tube, etc.) for installing a gradient coil. The qubit sample may be made of a non-magnetic material that does not affect a magnetic field, such as reinforced plastic, glass, or acrylic. The qubit sample can be manufactured in a shape other than a cylindrical shape, such as a polygonal column, but a shape that exhibits the same characteristics regardless of any direction in which an RF signal is propagated through an antenna and / or an RF transmitting coil unit installed in three directions of X, Y, and Z may be preferable.

[0081] In one embodiment, when there are multiple qubit samples (210), the multiple qubit samples may be spaced apart from each other and placed corresponding to predetermined positions within the magnet (120). For example, a first qubit sample may be placed at a predetermined first position, and a second qubit sample may be placed at a predetermined second position. Here, the first position and the second position may be different. In one embodiment, the first qubit sample and the second qubit sample may be placed so as not to touch each other.

[0082] When there are multiple qubit samples (210), a gradient coil (220), an RF transmitting coil unit (230), and an RF receiving coil (not indicated, also used as an RF transmitting coil) may be provided corresponding to each of the multiple qubit samples. One qubit sample may correspond to one gradient coil, one RF transmitting coil unit, and one RF receiving coil.

[0083] The gradient coil (220) may be provided corresponding to the qubit sample (210) inside the magnet (120). For example, the gradient coil (220) may be provided in an external area of ​​the qubit sample (210).

[0084] In one embodiment, the gradient coil (220) may include a Helmholtz coil. The Helmholtz coil may be a coil that makes the magnetic field constant in the space where the qubit sample is installed between two identical circular coils that share a central axis and are spaced apart from each other by the radius. The direction of the gradient magnetic field generated from the gradient magnetic coil (220) may all be directed in the same direction (e.g., +Z axis) as the direction of the magnetic field (B0) caused by the magnet.

[0085] In the case where there are multiple gradient coils (220) provided for each qubit sample, a unique number may be assigned to each of the multiple gradient coils. Each of the multiple gradient coils may apply a step-like discrete gradient field determined in correspondence with the unique number. For example, a unique number k sequentially determined (for example, when the number of multiple gradient coils is (2n+1) (where n is a natural number), k = -n, ~, -1, 0, +1, ~, +n) may be assigned to each of the multiple gradient coils, and a discrete gradient field determined in correspondence with the unique number k (For example, = kg) can be applied. Here, g can represent the gradient magnetic field difference that is constantly determined between two gradient magnetic field coils assigned with consecutive unique numbers. Ideal magnetic field by magnet and gradient magnetic fields per qubit The integrated magnetic field added to As such, the resonant frequency, i.e., the Larmor frequency, can also be set to different values ​​for each qubit. Therefore, a qubit system can independently control the quantum state of the hydrogen proton spin constituting a selected qubit by applying an RF pulse of a frequency matching the Larmor frequency set for that qubit through an RF transmitting coil, thereby distinguishing it from all other qubits.

[0086] In case there is a difference between the actual measured magnetic field applied by the magnet in the internal region of the gradient coil (220) dedicated to each qubit sample and the theoretically predetermined ideal magnetic field, a magnetic field required for correction can be additionally applied through the gradient coil (220) for magnetic field shimming of the magnet. For example, if the unique number assigned to the gradient coil (220) dedicated to a specific qubit sample is k, the actual magnetic field measurement value applied by the magnet at the location where the material (211) of the qubit sample is installed in the internal region of the kth gradient coil and the difference between B0 and the magnetic field of an ideally uniform magnet (i.e., the ideal magnetic field that is theoretically predetermined) (the magnetic field for compensating for the magnetic field inhomogeneity of the magnet) Discrete gradient field Magnetic field added to can be applied to the kth gradient magnetic coil. In this case, the integrated magnetic field B(k) applied to the kth qubit sample is the magnetic field measurement value by the actual magnet. and the magnetic field applied to the gradient magnetic field coil (including the above correction field) It is the same as adding You can obtain the result with correction as follows.

[0087] The RF transmitting coil unit (230) is placed between the qubit sample (210) and the gradient magnetic coil (220) inside the magnet (120), and can apply an RF pulse (radio frequency pulse) to the qubit sample installed inside the magnet (120). The RF transmitting coil unit (230) can control the state of the qubit by applying an RF pulse to the qubit sample (210).

[0088] In the case where there are multiple RF transmitting coil units (230) dedicated to each qubit sample, the multiple RF transmitting coil units can apply RF pulses of different Larmor frequencies according to the discrete gradient magnetic field applied from each of the multiple gradient magnetic field coils in response to the assigned unique number.

[0089] The RF transmitting coil unit (230) may include an RF signal generating device, a first RF transmitting coil (231), a second RF transmitting coil (232), and / or a third RF transmitting coil (233). The configuration of the RF transmitting coil unit (230) illustrated in FIG. 2 is merely a simplified example. In one embodiment of the present disclosure, the RF transmitting coil unit (230) may include other configurations for applying RF pulses, and only some of the disclosed configurations may constitute the RF transmitting coil unit (230).

[0090] The RF signal generating device can generate an RF signal having an angular velocity equal to the Larmor frequency of the qubit so as to rotate the qubit at an arbitrary angle around an arbitrary direction in three-dimensional space in order to control the spin state of a hydrogen proton in a specific qubit sample (210).

[0091] Referring to FIG. 2A, the first RF transmitting coil (231), the second RF transmitting coil (232), and the third RF transmitting coil (233) can cross in the three-axis (X-axis, Y-axis, Z-axis) directions so as to convert electricity provided from an RF signal generating device into a magnetic field and pass through a material region constituting the corresponding qubit. In one embodiment, the first RF transmitting coil (231) and the second RF transmitting coil (232) can be birdcage coils, and the third RF transmitting coil (233) can be a Helmholtz coil.

[0092] A first RF transmitting coil (231) may be placed in a first space between a qubit sample (210) and a gradient coil (220) inside a magnet (120). The first RF transmitting coil (231) may apply a first RF pulse (radio frequency pulse) inside the magnet (120). The first RF pulse may be a carrier wave of a first RF amplitude-modulated by the pulse. The carrier wave may be a reference waveform used to modulate a data signal.

[0093] The first RF pulse can rotate the nuclear spin by an angle ranging from 0 to 360 degrees about the X-axis. For example, the first RF pulse can have an angle of 90 degrees.

[0094] The material of the first RF transmitting coil (231) may be a metal for applying RF pulses, for example, copper. However, the material of the first RF transmitting coil (231) is not limited thereto.

[0095] The shape of the first RF transmitting coil (231) may be a birdcage shape, a spiral shape, a plate shape, a ring shape, etc. However, the shape of the first RF transmitting coil (231) is not limited thereto and may include various shapes for applying the first RF pulse.

[0096] The first RF transmitting coil (231) can apply a first RF pulse corresponding to the qubit sample (210) in a direction perpendicular to the magnetic field of the magnet (120) to the internal space containing the qubit sample (210).

[0097] When there are multiple first RF transmitting coils (231), the multiple first RF transmitting coils can transmit signals of different frequencies according to discrete gradient fields applied by gradient coils corresponding to unique numbers assigned identically to qubit samples. The multiple first RF transmitting coils can change the state of the qubit inside the first RF transmitting coil according to the applied first RF pulse.

[0098] A second RF transmitting coil (232) may be placed in a second space between the qubit sample (210) and the gradient coil (220) inside the magnet (120). The second RF transmitting coil (232) may apply a second RF pulse inside the magnet (120). The second RF pulse may be a carrier wave of the second RF amplitude-modulated by the pulse.

[0099] The second RF pulse can rotate the nuclear spin by an angle ranging from 0 to 360 degrees about the Y-axis. For example, the second RF pulse can have an angle of 180 degrees.

[0100] The material of the second RF transmitting coil (232) may be a metal for applying RF pulses, for example, copper. However, the material of the second RF transmitting coil (232) is not limited thereto.

[0101] The shape of the second RF transmitting coil (232) may be a cage shape, a spiral shape, a plate shape, a ring shape, etc. However, the shape of the second RF transmitting coil (232) is not limited thereto and may include various shapes for applying the second RF pulse.

[0102] The second RF transmitting coil (232) can apply a second RF pulse corresponding to the qubit sample (210) to the internal space including the qubit sample (210) in a direction orthogonal to the magnetic field applied by the magnet (120) and the magnetic field applied by the first RF transmitting coil (231).

[0103] When there are multiple second RF coils (232), the multiple second RF coils can transmit signals of different frequencies according to discrete gradient fields applied by gradient coils corresponding to unique numbers identical to the qubit-assigned samples. The multiple second RF coils can change the state of the qubit inside the second RF coil according to the applied second RF pulse.

[0104] The third RF transmitting coil (233) may be placed in a third space between the qubit sample (210) and the gradient coil (220) inside the magnet (120). The third RF transmitting coil (233) may apply a third RF pulse inside the magnet (110). The third RF pulse may rotate the nuclear spin around the Z-axis, thereby shifting the phase of the spin that precesses around the Z-axis. Therefore, the third RF pulse may be an amplitude pulse without a carrier wave.

[0105] The third RF pulse can rotate the nuclear spin by an angle ranging from 0 to 360 degrees about the Z-axis. For example, the third RF pulse can have an angle of 90 degrees.

[0106] The material of the third RF transmitting coil (233) may be a metal for applying RF pulses, for example, copper. However, the material of the third RF transmitting coil (231) is not limited thereto.

[0107] The shape of the third RF transmitting coil (233) may be a spiral shape, a plate shape, a ring shape, etc. However, the shape of the third RF transmitting coil (233) is not limited thereto and may include various shapes for applying the third RF pulse.

[0108] The third RF transmitting coil (233) can apply a third RF pulse corresponding to the qubit sample (210) in a direction parallel to the magnetic field of the magnet (120) to the internal space containing the qubit sample (210).

[0109] When there are multiple third RF transmitting coils (233), the multiple third RF transmitting coils can transmit signals of different frequencies according to discrete gradient fields applied by gradient coils corresponding to unique numbers assigned identically to qubit samples. The multiple third RF transmitting coils can change the state of the qubit inside the third RF transmitting coil according to the applied third RF pulse.

[0110] In one embodiment, a coordinate axis in a direction parallel to the magnetic field of the magnet (120) in a three-dimensional space may be referred to as a Z axis, a coordinate axis in a direction parallel to the magnetic field applied by the first RF transmitting coil (231) may be referred to as an X axis, and a coordinate axis in a direction parallel to the magnetic field applied by the second RF transmitting coil (232) may be referred to as a Y axis. In this case, the directions of the gradient magnetic field applied by the gradient magnetic field coil (220), the magnetic field for magnetic field correction of the magnet (120), and the magnetic field applied by the third RF transmitting coil (233) may be parallel to the Z axis.

[0111] Referring to FIG. 2b, when the second RF transmitting coil is not provided, the second RF pulse is identical to an RF pulse whose phase is 90 degrees different from the first RF pulse applied through the first RF transmitting coil, so that an RF pulse identical to the second RF pulse corresponding to the qubit sample can be applied to the internal space including the qubit sample using the first RF transmitting coil (240).

[0112] In addition, when the third RF transmitting coil is not provided, the first RF pulse and the second RF pulse can be combined to implement an RF pulse identical to the third RF pulse, so the first RF transmitting coil and the second RF transmitting coil can be used together, or the first RF transmitting coil (240) alone can be used to apply the third RF pulse corresponding to the qubit sample to the internal space including the qubit sample.

[0113] In one embodiment, the gradient coil can hold a qubit sample within it. The location of the qubit sample within the gradient coil can be at the center of the gradient coil. The gradient coil can be provided in the form of a cylindrical mechanism, either integrally or separately from the cylindrical mechanism. However, the location of the qubit sample and the shape of the gradient coil are not limited thereto.

[0114] In one embodiment, the first RF transmitting coil (a cage-shaped or solenoid coil for RF pulses in the X-axis direction), the second RF transmitting coil (a cage-shaped or solenoid coil for RF pulses in the Y-axis direction), and the third RF transmitting coil (a Helmholtz coil for RF pulses in the Z-axis direction) may be coils that are tightly wound in a cylindrical shape with thin enamel-coated wires that have a strength that allows them to maintain a circular shape when bent circularly.

[0115] The third RF transmitting coil can be positioned inside a gradient coil (or a cylindrical device with a gradient coil installed) and fixed so that the magnetic field is directed along the same Z-axis.

[0116] A second RF transmitting coil (a cage-shaped or solenoid coil for RF pulses in the Y-axis direction) can be inserted inside the third RF transmitting coil such that the Y-axis magnetic field direction and the Z-axis magnetic field direction are orthogonal to each other.

[0117] The first RF transmitting coil (a cage-shaped or solenoid coil for RF pulses in the X-axis direction) can be inserted inside the third RF transmitting coil so that the X-axis magnetic field direction is orthogonal to the Y-axis and Z-axis magnetic field directions at the same time.

[0118] When a first RF pulse is applied to a qubit sample (210) placed inside a first RF transmitting coil (231), the spin of the material (211) included in the qubit sample (210) can rotate by an angle determined by the first RF pulse around the X-axis on a plane including the Z-axis and the Y-axis.

[0119] When a second RF pulse is applied to a qubit sample (210) placed inside a second RF transmitting coil (232), the spin of the material (211) included in the qubit sample (210) can rotate by an angle determined by the second RF pulse around the Y-axis on a plane including the Z-axis and the X-axis.

[0120] When a third RF pulse is applied to a qubit sample (210) placed inside a third RF transmitting coil (233), the spin of the material (211) included in the qubit sample (210) can rotate by an angle determined by the third RF pulse around the Z axis on a plane including the X axis and the Y axis.

[0121] The state of the qubit can be restored by applying a second-first RF pulse having a 90-degree angle to the qubit sample (210) placed inside the second RF transmitting coil (232) and then applying a second-second RF pulse having a 180-degree angle, which results in the dephasing relaxation caused by the inhomogeneity of the magnetic field of the magnet (120) due to the spin echo phenomenon that occurs.

[0122] The state of the qubit sample (210) may correspond to the application of a Hadamard gate when a second RF pulse having an angle of 90 degrees is applied from the second RF transmitting coil (232) and then a first RF pulse having an angle of 180 degrees is applied from the first RF transmitting coil (231).

[0123] Hadamard gate can be a gate that turns the state of a qubit in the state of |0> or |1> into a quantum superposition state where |0> and |1> exist simultaneously. The determinant of Hadamard gate is It could be.

[0124] If a separate RF receiving coil (not shown) is not provided, a duplexer can be connected to the first RF transmitting coil to enable use for both transmission and reception.

[0125] The RF receiving coil can receive an RF signal emitted from the qubit sample (210) due to an applied RF pulse. The RF receiving coil can be provided inside the magnet (120). For example, the RF receiving coil can be provided between the gradient coil (220) and the RF transmitting coil unit (230).

[0126] In one embodiment, when the RF receiving coil does not exist separately and is combined with the first RF transmitting coil, the RF signal emitted after the RF transmitting pulse ends may be received from the qubit sample (210) that has absorbed energy due to the RF transmitting pulse applied from the RF transmitting coil unit (230). In this case, the control unit, which will be described later with reference to FIG. 4, may amplify the signal through a pre-amplifier after passing it through a duplexer provided to separate the RF signal for spin control from the transmitting signal. In addition, the control unit may process the signal received from the RF transmitting coil unit (230) by obtaining a baseband signal through a quadrature demodulator and a low-pass filter.

[0127] Qubits can simultaneously represent multiple bits by utilizing quantum superposition states. For example, a qubit can represent each value as a probability, such as '|0> with a 20% probability, |1> with an 80% probability.' When observed, a qubit can be determined to be in a single state, as the quantum superposition state is released.

[0128] The state of a qubit can determine the probability of the |0> state and the |1> state, respectively, based on a selected time. The |0> state can correspond to the equilibrium state of the material constituting each qubit. The |1> state can correspond to the excited state of the material.

[0129] The qubit may be a signal generated according to a spin echo phenomenon that occurs when a second RF pulse having a different angle from the first RF pulse is applied to the qubit sample (210) from the second RF transmission coil (232). Here, the first RF pulse and the second RF pulse may have different angles. For example, the first RF pulse and the second RF pulse may include signals having a difference of 90 degrees. For example, the first RF pulse may have an angle of 90 degrees, and the second RF pulse may have an angle of 180 degrees.

[0130] Spin echo can refer to an echo signal generated after a certain period of time when pulses of different angles are applied to the spins of electrons or nuclei in spin magnetic resonance. For example, spin echo can be an echo signal generated after a certain period of time when 90-degree and 180-degree pulses are sequentially applied to the spins of hydrogen nuclei generated by the magnetic field of a magnet (120) and / or the gradient magnetic field of a gradient magnetic coil (220).

[0131] Specifically, the spins can be aligned by the Zeeman effect. The Zeeman effect may mean aligning the spins by the magnetic field of the magnet (120) and / or the gradient magnetic field of the gradient magnetic coil (220), and aligning some of the spins in the same direction (+) and other parts of the spins in the opposite direction (-) depending on the strength of the magnetic field and / or the gradient magnetic field. The spins aligned in the same direction (+) and the opposite direction (-) may have different energies.

[0132] When a first RF pulse of 90 degrees is applied to the nucleus (spin) through a first RF transmission coil (231) while the nucleus (spin) of a material included in a qubit sample (210) is aligned by the Zeeman effect, the nucleus (spin) can be positioned in a horizontal direction on the XY plane. Then, when a second RF pulse of 180 degrees is applied to the nucleus (spin) through a second RF transmission coil (232), a spin echo phenomenon can occur. A signal generated by this spin echo phenomenon can be detected by an RF reception coil.

[0133] A qubit can determine the probability of each of the '|0>' state and the '|1>' state based on a selected time. The '|0>' state may correspond to an equilibrium state of a material, and the '|1>' state may correspond to an excited state of the material. For the convenience of explanation in this specification, a method in which a qubit is implemented in the |0> state and the |1> state is exemplarily described. As another example, depending on the implementation aspect, the qubit may be implemented through the probability for a state corresponding to any two values ​​between |0> and |1>. As another example, depending on the implementation aspect, the qubit may be implemented through the probabilities of each of three or more states.

[0134] FIG. 3 is a diagram showing a state in which a qubit module is provided inside a magnet in a qubit system according to some embodiments of the present disclosure.

[0135] Referring to FIG. 3, a qubit system may include a qubit module (320) inside a magnet (310). The qubit module (320) may include a plurality of qubit sub-modules. Each of the plurality of qubit sub-modules may include a plurality of qubit samples, a plurality of gradient coils, a plurality of RF transmitting coil units, a plurality of RF receiving coils, etc. For example, one qubit sub-module constituting the qubit module (320) may include one qubit sample, one gradient coil, one RF transmitting coil unit, and one RF receiving coil. However, the qubit sub-module is not limited thereto, and in one embodiment of the present disclosure, the qubit sub-module may include other configurations for generating a qubit, and only some of the disclosed configurations may constitute the qubit sub-module.

[0136] Each of the plurality of gradient coils may be assigned a unique number. Each of the plurality of gradient coils may apply a discrete gradient field determined in correspondence with the unique number. For example, each of the plurality of gradient coils may be sequentially assigned a unique number k (for example, when the number of the plurality of gradient coils is (2n+1) (where n is a natural number), k = -n, ~, -1, 0, +1, ~, +n), and a discrete gradient field G(k) determined in correspondence with the unique number k (for example, G(k) = kg) may be applied. In one embodiment, the unique number of each of the plurality of qubit sub-modules may correspond to the unique number assigned to the corresponding gradient coil. For example, when the unique number assigned to the first gradient coil included in the first qubit sub-module is 1, the unique number of the first qubit sub-module may be 1.

[0137] As described above, when the gradient coil, RF transmitting coil, and RF receiving coil are provided for each qubit sample, the qubit system can freely designate and assign a virtual unique serial number to each qubit according to convenience, regardless of the actual installation order or spatial location. For example, when developing a quantum computer composed of a large number of qubits (for example, millions or tens of millions of qubits), the qubit system can group the qubits or divide them into a hierarchical structure as needed, designate and assign a unique number for each group or hierarchy, and assign a unique identification number to each of the multiple qubits belonging to a specific group or hierarchy.

[0138] FIG. 4 is a diagram illustrating a control unit of a qubit system according to some embodiments of the present disclosure.

[0139] Referring to FIG. 4, the qubit system may include a “magnet, heating plate, and qubit module (410)” and a control unit (420). The description of “magnet, heating plate, and qubit module (410)” may be replaced with the description described above with reference to FIGS. 1 to 3.

[0140] The control unit (420) may include a chip, microchip, or the like for controlling multiple components of the qubit system. For example, at least one of the multiple components of the qubit system may be present on the control unit (420). In another example, the multiple components of the qubit system may exist separately from the control unit (420).

[0141] The control unit (420) may include a logic gate that is connected to the qubit and processes information generated from the qubit. The logic gate may include a quantum logic gate. The control unit may receive data from the qubit at a predetermined time and adjust the probability of the qubit's '|0>' state and '|1>' state, respectively.

[0142] The control unit (420) may include a spectrometer (421), a power amplifier (422), a duplexer (423), a tuning matching circuit (424), a pre-amplifier (425), and a computing device (426). The configuration of the control unit (420) illustrated in FIG. 4 is merely a simplified example. In one embodiment of the present disclosure, the control unit (420) may include other configurations for generating qubits, and only some of the disclosed configurations may constitute the control unit (420).

[0143] A spectrometer (421) is a device that measures the spectrum of light emitted or absorbed by a material, and may include a nuclear magnetic resonance spectrometer. A nuclear magnetic resonance spectrometer may be a spectroscopic analyzer that measures the rotation of atomic nuclei of a sample to be analyzed through RF (radio frequency) resonance. The spectrometer (421) may include a transmitting module (Tx) that transmits RF pulses, etc., a receiving module (Rx) that receives signals, etc.

[0144] The power amplifier (422) may be a device for amplifying power. For example, the power amplifier (422) may receive an RF pulse from the spectrometer (421) and amplify the received RF pulse.

[0145] The transceiver (423) may be a device that processes transmission and reception. The transceiver (423) may separate a signal between an antenna and a transmitter or receiver, and transmit the signal to each device (e.g., a tuning matching circuit (424), a pre-amplifier (425), etc.) at a required time. For example, the transceiver (423) may receive a signal from a power amplifier (422) and a tuning / matching circuit (424). In addition, the transceiver (423) may transmit a signal to the tuning / matching circuit (424) and the pre-amplifier (425).

[0146] The tuning / matching circuit (424) may be a circuit that adjusts and transmits the frequency of an electrical signal. The tuning / matching circuit (424) may include a circuit that performs impedance matching of an RF transmitting coil and an RF receiving coil and a circuit that performs frequency tuning. For example, the tuning / matching circuit (424) may receive a signal from a transceiver (423), perform impedance matching and frequency tuning on the received signal, and transmit the processed signal to a qubit module of the “magnet, heating plate, and qubit module (410).” As another example, the tuning matching circuit (424) may receive a signal from a qubit module of the “magnet, heating plate, and qubit module (410),” perform impedance matching and frequency tuning on the received signal, and transmit the processed signal to the transceiver (423).

[0147] The pre-amplifier (425) may be a device that amplifies the amplitude of an input signal. The pre-amplifier (425) may include a low noise amplifier. The low noise amplifier may amplify the amplitude of the input signal by minimizing added noise. In one embodiment, the pre-amplifier (425) may receive a signal from the transceiver (423), amplify the amplitude of the received signal, and transmit the amplified signal to the receiving module of the spectrometer (421).

[0148] The computing device (426) can control at least one of the spectrometer (421), the power amplifier (422), the transducer (423), the tuning / matching circuit (424), and / or the pre-amplifier (425). For example, the operations and steps performed in the control unit (420) can be controlled and performed by the processor of the computing device (426).

[0149] In one embodiment, a signal transmitted from the transmission module of the spectrometer (421) to the qubit module of the “magnet, heating plate, and qubit module (410)” and a signal transmitting the state information of the qubit sample detected by the RF receiving coil of the qubit module to the receiving module of the spectrometer (421) may jointly pass through the transceiver (423). By jointly using the transceiver (423), the RF transmitting coil and the RF receiving coil can be processed with the same single coil without being separated, so that the circuit can be simple and efficient. However, the transmission and reception methods are not limited thereto.

[0150] FIG. 5 is a diagram illustrating a shielding device of a qubit system according to some embodiments of the present disclosure.

[0151] Referring to FIG. 5, a shielding device (520) may be provided to protect the “magnet, heating plate, and qubit module (510)” of the qubit system.

[0152] The shielding device (520) may be a structure for shielding a magnetic field and / or RF signal generated from the “magnet, heating plate, and qubit module (510).” The shielding device (520) is provided on the outside of the “magnet, heating plate, and qubit module (510),” thereby shielding the magnetic field and / or RF signal generated from the “magnet, heating plate, and qubit module (510).”

[0153] The material of the shielding device (520) may be ferrite, metal, plastic, etc. The shape of the shielding device (520) may be a shape that surrounds the “magnet, heating plate, and qubit module (510)”, for example, a hexahedral shape, a mesh shape, etc. However, the material and shape of the shielding device (520) are not limited thereto.

[0154] In one embodiment, the shielding device (520) can protect the “magnet, heating plate and qubit module (510)” and the control unit. The shielding device (520) is provided outside the “magnet, heating plate and qubit module (510)” and the control unit, thereby shielding the magnetic field and / or RF signal generated from the “magnet, heating plate and qubit module (510)” and the control unit.

[0155] FIG. 6 is a diagram illustrating an expansion method of a qubit system according to some embodiments of the present disclosure.

[0156] Referring to FIG. 6, a qubit system (600) including a “magnet, heating plate, and qubit module (610)” and a shielding device (620) can be expanded by stacking them in a three-dimensional space.

[0157] In one embodiment, the qubit system (600) may be configured by combining two magnets having a width (200 mm), a height (50 mm), and a thickness (30 mm) to form a 0.5T magnet having a height of 100 mm, and may include N=10 qubits inside the magnet, and a shielding device (620) capable of shielding magnetic fields and RF signals on the outside of the magnet. In this way, when the qubit system (600) including 10 qubits is installed in a 10 x 10 x 10 configuration in a three-dimensional space having a width of approximately 4 m, a height of approximately 2 m, and a height of approximately 2 m, a quantum computer including 10,000 qubits can be configured.

[0158] Below, a method for controlling a qubit state for quantum information processing in a qubit system according to some embodiments of the present disclosure is described.

[0159] FIG. 7 is a diagram illustrating a method for controlling the state of a qubit in a qubit system according to some embodiments of the present disclosure. The steps illustrated in FIG. 7 are exemplary steps. Accordingly, it will be apparent to those skilled in the art that some of the steps illustrated in FIG. 7 may be omitted or additional steps may be present without departing from the scope of the present disclosure. Furthermore, specific details regarding the configurations described in FIG. 7 (e.g., the configurations of the qubit system) may be replaced with those described above with reference to FIGS. 1 to 6.

[0160] Referring to FIG. 7, a qubit system (e.g., a control unit of a qubit system, a processor of a computing device, etc.) can apply an RF pulse to the inside of a magnet by an RF transmitting coil unit placed between a qubit sample provided inside a magnet and a gradient coil provided inside the magnet corresponding to the qubit sample (710).

[0161] If the qubit system has multiple qubit samples, the multiple qubit samples can be spaced apart from each other to correspond to predetermined positions inside the magnet.

[0162] The qubit system can arrange the gradient coil, the RF transmitting coil, and the RF receiving coil to correspond to each of the multiple qubit samples.

[0163] The qubit system can be arranged so that one qubit sample corresponds to one gradient coil, one RF transmit coil section, and one RF receive coil.

[0164] If a qubit system has multiple gradient coils, each gradient coil can be assigned a unique number. The qubit system can apply a discrete gradient field corresponding to the unique number to each of the multiple gradient coils.

[0165] When a qubit system has multiple RF transmitting coil units, different RF pulses can be applied to each of the multiple RF transmitting coil units according to a discrete gradient field applied from each of the multiple gradient coils corresponding to a unique number.

[0166] When a qubit system has multiple RF transmitting coil units, the state of a qubit generated from a qubit sample located inside each of the multiple RF transmitting coil units can be changed based on an RF pulse applied to each of the multiple RF transmitting coil units.

[0167] The qubit system can additionally apply a magnetic field to the gradient coil to compensate for the difference between the actual magnetic field applied by the magnet in the internal region of the gradient coil and the theoretically predetermined ideal magnetic field.

[0168] The RF transmitting coil unit may include a first RF transmitting coil disposed in a first space between a qubit sample and a gradient coil inside the magnet, and applying a first RF pulse (radio frequency pulse) inside the magnet.

[0169] The RF transmitting coil unit may include a second RF transmitting coil disposed in a second space between the qubit sample and the gradient coil inside the magnet, and applying a second RF pulse inside the magnet.

[0170] The RF transmitting coil unit may include a third RF transmitting coil disposed in a third space between the qubit sample and the gradient coil inside the magnet, and applying a third RF pulse inside the magnet.

[0171] The qubit system can apply a first RF pulse corresponding to the qubit sample to an internal space containing the qubit sample in a direction perpendicular to the magnetic field of the magnet using a first RF transmitting coil.

[0172] The qubit system can apply a second RF pulse corresponding to the qubit sample to the internal space containing the qubit sample in a direction perpendicular to the magnetic field applied by the magnet and the magnetic field applied by the first RF transmitting coil simultaneously using the second RF transmitting coil.

[0173] The qubit system can apply a third RF pulse corresponding to the qubit sample to the internal space containing the qubit sample in a direction parallel to the magnetic field of the magnet using a third RF transmitting coil.

[0174] The qubit system can generate a qubit state from a qubit sample based on an applied RF pulse (720). The qubit may be a signal generated by a spin echo phenomenon that occurs when a second RF pulse having a different angle from the first RF pulse is applied to the qubit sample from a second RF transmitting coil. Here, the first RF pulse and the second RF pulse may have different angles. For example, the first RF pulse and the second RF pulse may include signals having a difference of 90 degrees. For example, the first RF pulse may have an angle of 90 degrees, and the second RF pulse may have an angle of 180 degrees.

[0175] The qubit system according to some embodiments of the present disclosure described above is based on a technology applied to a diagnostic magnetic resonance imaging (MRI) device that has been commercially developed and is widely used in hospitals, and some of the MRI technologies are modified and supplemented so that they can be applied to the development of a quantum computing platform, and new technologies are additionally developed and applied, thereby developing and fusing a unique technology that is differentiated from various existing qubit systems, but is relatively easy to implement and has low difficulty, thereby significantly shortening the time required for the development and commercialization of a magnetic resonance-based discrete multiple qubit system for quantum information processing.

[0176] In addition, the qubit system according to some embodiments of the present disclosure can be easily developed by utilizing technology that can operate at room temperature, without using extremely difficult technologies such as cryogenic temperatures and ultra-vacuum, which are required in various existing qubit systems, by utilizing permanent magnets.

[0177] In addition, the qubit system according to some embodiments of the present disclosure can easily expand the number of qubits by stacking them in a three-dimensional space by developing a large number of qubits using small plate-shaped permanent magnets and applying a protective device for shielding magnetic fields and RF signals.

[0178] FIG. 8 is a diagram illustrating a quantum information processing method using a qubit system according to some embodiments of the present disclosure. The steps illustrated in FIG. 8 are exemplary steps. Therefore, it will be apparent to those skilled in the art that some of the steps illustrated in FIG. 8 may be omitted or additional steps may be present without departing from the scope of the present disclosure. In addition, specific details regarding the configurations described in FIG. 8 (e.g., configurations of the qubit system) may be replaced with the contents described above with reference to FIGS. 1 to 7. In one embodiment, the steps illustrated in FIG. 8 may be performed in a qubit system. For example, the steps illustrated in FIG. 8 may be performed by a control unit of the qubit system.

[0179] In the present disclosure, quantum information processing technologies such as quantum computing, quantum communication, and quantum sensing based on quantum mechanical principles can be implemented using a qubit system.

[0180] Quantum computing is a new concept of computer that can perform ultra-high-speed parallel operations by utilizing quantum characteristics such as quantum superposition and quantum entanglement. It can be classified into algorithms, simulators, and general-purpose quantum computers.

[0181] Quantum communication is a network technology for physical security communication and connection between quantum devices that utilizes the characteristics of quantum, and can be classified into quantum cryptography, quantum networks, transmission, and error correction codes.

[0182] Quantum sensing is a technology that enables ultra-precision measurement by exploiting changes in quantum states caused by electromagnetic fields, gravity, light, and other influences. It can be categorized into inertia and gravity, electromagnetic fields, light and imaging, and time and frequency sensing. Quantum information processing technology can generate quantum states based on interacting qubits, control changes in these states using reversible computational methods, and measure and analyze them. Quantum information processing technology can vary depending on the qubit system.

[0183] Referring to FIG. 8, a processor of a computing device can generate and control a qubit state using a qubit system (810).

[0184] In a qubit system, hydrogen (which constitutes the material contained in the qubit) 1 H) The nucleus has a 1 / 2 spin and therefore can have an intrinsic magnetic moment. When a hydrogen nucleus is placed inside a magnetic field (B) of a magnet, the energy difference due to the Zeeman effect can be quantized into two quantum spin states, |0> and |1>, by . Here, B is the strength of the magnetic field, is the gyromagnetic ratio, a constant that depends on the nuclide, and h may be the Planck constant.

[0185] The transition between the Zeeman levels of two quantum states can be induced by a magnetic field rotating at an angular velocity equal to the precession frequency of the spin in the field. The precession frequency, or Larmor frequency, can be derived from Equation 1 below.

[0186]

[0187] Here, ω is the angular velocity proportional to the magnetic field strength B, can be a frequency proportional to the Zeeman energy difference. Hydrogen proton ( 1 For H), the Ramo frequency is approximately 42.6 to 426 MHz when the magnetic field is 1 T to 10 T, which may fall within the RF (radio frequency) band of the electromagnetic spectrum.

[0188] The hydrogen proton energy in the RF band is low, on the order of μev, making it fundamentally impossible or very difficult to measure a single hydrogen proton. Therefore, each qubit sample may require a fairly large sample containing an ensemble of identical molecules. For example, a single qubit sample may have about 10 22 The same hydrogen protons ( 1 When composed of about 1 g of distilled water having H), the hydrogen proton spins can be distributed in the low energy state |0> and the high energy state |1> according to the Boltzmann distribution. The relative net population excess of the spins distributed in the low energy state |0> is ε = 10 of the total number of spins in each qubit sample when the magnetic field of the magnet is 1.0 T. -6 The percentage may be lower than expected.

[0189] Magnetic resonance experiments can typically be described using a vector model based on the Bloch sphere. The Bloch sphere can be a tool for visually representing the state of a qubit. The Bloch sphere has a spherical shape in three-dimensional space, and the surface of the sphere can represent the state of a qubit. The Bloch sphere can represent the state of a qubit as a point on the surface of the Bloch sphere. For example, the upper pole of the Bloch sphere can represent the |0> state of a qubit, and the lower pole can represent the |1> state of a qubit.

[0190] In a pure state, an isolated single spin is According to the quantum superposition rule of the same formula, it can be described using a density matrix ρ as in mathematical formula 2 below.

[0191]

[0192] Here represents the spin vector of the nucleus, or Bloch vector, which points in an arbitrary direction when a strong external magnetic field (e.g., a magnetic field generated by a magnet, a gradient coil, an RF transmitting coil, etc.) is turned off. can be the Pauli matrix. In the case of a pure state, the length of the Bloch vector is 1, so the Bloch vector exists on the Bloch sphere. can be satisfied. On the other hand, in the case of a mixed state, since the length of the Bloch vector is not 1, the Bloch vector may not exist on the Bloch sphere. In one embodiment, Equation 2 may be normalized so that the trace of the density operator is 1.

[0193] In a qubit system, when a strong external magnetic field (e.g., a magnetic field generated by a magnet, a gradient coil, an RF transmitting coil, etc.) is applied, all hydrogen proton spins constituting a single qubit sample ( 1 H) can be a highly mixed state which can be described by the density operator ρ as in the mathematical expression 3 below.

[0194]

[0195] Here, ε is the relative net population access of the hydrogen protons constituting the single qubit sample in the pure state ket |0>, which is approximately 10 -6 It's about that much, can represent the best mixed state with the number of relative populations (1-ε) as a 2x2 identity matrix normalized by two-dimensional ket spaces. Equation 3 can be a nearly random state with a small excess of ket states |0>. In addition, the diagonal sum of the density operator ρ in Equation 3 can be normalized to 1.

[0196] In a qubit system, the expression representing the initial state of each qubit is the thermal equilibrium state. can be derived from the fact that it is proportional to . Here, H is the internal Hamiltonian (expressed in energy units) of the nuclear spin of the molecule constituting the qubit sample, T is the temperature, and It can be the Boltzmann constant, a universal constant used when dealing with ideal gases as functions of pressure, volume, and temperature. In this case, is a very small value, and the coupling term of the qubit sample composed of a material (e.g., distilled water) can be ignored. Therefore, we can obtain the following mathematical expression 4.

[0197]

[0198] Here is the energy difference between the |0> and |1> states. It is the same as, can be a relative net excess of the pure state |0>. Clearly, the available initial states may be very far from those required for standard quantum information processing. However, they can still be used to perform interesting operations. Using useful magnetic resonance-based techniques, it may be possible to transform the available initial states into pseudopure states that behave like the initial states required for quantum information processing. In one embodiment, only the non-diagonal part of the density matrix may contribute to the magnetization. Furthermore, all unitary operators used, not just non-unitary ones, are can be preserved. And, all specifications may be relative. In one embodiment, for measurement, the absolute magnitude of the magnetization may not be important. The magnetization may be strong enough to be observed over noise.

[0199] The processor can transform the state of the qubit so that a predetermined quantum algorithm can be implemented (820).

[0200] In one embodiment, the processor can transform the state of a qubit using a rotation operator of a quantum gate included in a predetermined quantum algorithm.

[0201] A quantum algorithm can be an algorithm for solving a problem using a quantum computer.

[0202] Quantum gates can be elements that represent operations applied to qubits in a quantum computer. Quantum gates can transform the quantum state of qubits. Quantum gates can perform operations through matrix multiplication of complex vectors. Quantum gates can include Hadamard gates, Pauli gates, phase shift gates (e.g., S gates, T gates, etc.), and CNOT gates.

[0203] Rotation operators are operators that rotate the state of a qubit around each axis, and may include, for example, Pauli gates.

[0204] Pauli gates can include Pauli-X gates, Pauli-Y gates, and Pauli-Z gates.

[0205] A Pauli-X gate can be a gate that rotates the state of a qubit 180 degrees around the X-axis. A Pauli-X gate can perform an operation that inverts the state of a qubit.

[0206] A Pauli-Y gate can be a gate that rotates the state of a qubit 180 degrees around the Y-axis. A Pauli-Y gate can perform an operation that inverts the state of a qubit and assigns a negative sign to a complex coefficient.

[0207] A Pauli-Z gate can be a gate that rotates the state of a qubit 180 degrees around the Z-axis. A Pauli-Z gate can perform an operation on the state of a qubit that changes the phase of the state.

[0208] Meanwhile, the basic commutation relation of angular-momentum can correspond to the mathematical expression 5 below.

[0209]

[0210] Since Equation 5 does not have a commutative relation, the rotation group in three-dimensional space can be non-Abelian. The commutation relation can summarize all the fundamental properties of rotation in three dimensions in a concise manner. To obtain the commutation relation of Equation 5, J1 can be a rotation generator around the lth axis. Furthermore, to obtain the commutation relation of Equation 5, rotations around different axes may not be commutative.

[0211] The minimum dimension N for which the moment exchange relation is realized can be N=2. Spin operator can be defined by the following mathematical equations 6, 7, and 8.

[0212]

[0213]

[0214]

[0215] In equations 6, 7, and 8, the spin operator is J l S l If we change it to , we can satisfy the exchange relation of mathematical expression 5. In one embodiment, it may be desirable to realize the exchange relation in the minimum dimension.

[0216] Now, a finite angle around the z-axis Consider that it rotates as much as |a>. If the ket state of the 1 / 2 spin system before rotation is given as |a>, then the ket state after rotation is |a> R can be expressed as mathematical formula 9 below.

[0217]

[0218] Here, can be expressed as mathematical equation 10 below.

[0219]

[0220] To see if the above operator actually rotates the physical system, the expectation If applied, it can be expressed as mathematical equation 11 below.

[0221]

[0222] Therefore, if calculated using mathematical expression 10, the calculation result can correspond to mathematical expression 12 below.

[0223]

[0224] If mathematical expression 6 is substituted into mathematical expression 12, the result of the substitution can correspond to mathematical expression 13 below.

[0225]

[0226] =

[0227] =

[0228] Now, let us assume an arbitrary operator A and function f(A) and describe it below.

[0229] If the relationship holds, is an eigenket of A and a may be an eigenvalue of operator A. Here, the eigenket If is an eigenvalue of operator f(A) which is a function of A, then the eigenvalue of f(A) is obtained by substituting the eigenvalue a of operator A into the A term of the function of operator f(A), so can satisfy. In mathematical expression 13, operator A is S z Let f(A) be Then, using mathematical expression 8, we can obtain mathematical expressions 14 and 15 below.

[0230]

[0231]

[0232] Looking at equations 14 and 15, |0> and |1> are S z It is a unique jacket, and can be each eigenvalue. Eigenvalue is the eigenvalue |0>, and the eigenvalue is a unique ket |1> for f(S z ) in the exponent term z By substituting each of them, we can obtain mathematical equations 16 and 17 below.

[0233]

[0234]

[0235] Now, in Equation 13, by substituting Equations 16 and 17 for the state ket and the complex conjugate for the state bra, we can obtain Equation 18 below.

[0236]

[0237] =

[0238] =

[0239] =

[0240] Here and can correspond to the above mathematical expressions 6 and 7, respectively.

[0241] In one embodiment, the processor can measure the state of the transformed qubit (830).

[0242] Measurement can be the process of separating the state of a qubit into one of the basis states and obtaining a measurement result through the separated state. For example, a processor can obtain a state of |0> or |1> by performing a measurement on the state of a qubit in the Z basis state in a quantum circuit. If the measured state of the qubit is |0>, the processor can determine the state as 0 using a classical bit. If the measured state of the qubit is |1>, the processor can determine the state as 1 using a classical bit.

[0243] In one embodiment, the processor can analyze the results of measuring the state of the qubit (840).

[0244] In one embodiment, the processor can compare the measured value included in the result with the expected value corresponding to a predetermined quantum algorithm. Based on the comparison between the measured value and the expected value, the processor can analyze quantum noise, errors, etc., and modify the quantum algorithm to improve the quantum algorithm (e.g., improve the quantum circuit).

[0245] In some embodiments of the present disclosure, a processor may use a qubit system to initialize a state of a qubit of a qubit sample included in the qubit system.

[0246] The processor can change the state of a qubit by applying an RF pulse through an RF transmitting coil section corresponding to a qubit sample. In one embodiment, the processor can change the state of a qubit using an RF pulse corresponding to a rotation operator of a predetermined quantum gate.

[0247] The processor can measure the state of the converted qubit through an RF receiving coil equipped corresponding to the qubit sample.

[0248] The processor can analyze the results of measuring the state of the qubit. In one embodiment, the processor can compare the measured value included in the result with the expected value corresponding to the rotation operator of a predetermined quantum gate.

[0249] It will also be apparent to those skilled in the art that some of the steps in FIG. 8 may be omitted or additional steps may be present without departing from the scope of the present disclosure.

[0250] FIG. 9 is a simplified, general schematic diagram of an exemplary computing environment in which embodiments of the present disclosure may be implemented.

[0251] Although the present disclosure has been described above generally in the context of computer-executable instructions that may be executed on one or more computers, those skilled in the art will appreciate that the present disclosure may be implemented in combination with other program modules and / or as a combination of hardware and software.

[0252] In general, modules herein include routines, procedures, programs, components, data structures, and the like that perform particular tasks or implement particular abstract data types. Furthermore, those skilled in the art will appreciate that the methods of the present disclosure can be implemented with other computer system configurations, including single-processor or multiprocessor computer systems, minicomputers, mainframe computers, as well as personal computers, handheld computing devices, microprocessor-based or programmable consumer electronics, and the like, each of which may be operatively connected to one or more associated devices.

[0253] The described embodiments of the present disclosure can also be practiced in distributed computing environments, where certain tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote memory storage devices.

[0254] Computers typically include a variety of computer-readable media. Any computer-accessible media can be computer-readable media, including volatile and nonvolatile media, transitory and non-transitory media, removable and non-removable media. By way of example, and not limitation, computer-readable media can include computer-readable storage media and computer-readable transmission media.

[0255] Computer-readable storage media includes volatile and nonvolatile media, transitory and non-transitory media, removable and non-removable media implemented in any method or technology for storing information such as computer-readable instructions, data structures, program modules or other data. Computer-readable storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital video disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium that can be accessed by a computer and used to store the desired information.

[0256] Computer-readable transmission media typically includes any information delivery media that embodies computer-readable instructions, data structures, program modules, or other data in a modulated data signal, such as a carrier wave or other transport mechanism. The term modulated data signal means a signal that has one or more of its characteristics set or changed so as to encode information in the signal. By way of example, and not limitation, computer-readable transmission media includes wired media, such as a wired network or direct-wired connection, and wireless media, such as acoustic, RF, infrared, or other wireless media. Combinations of any of the above are also intended to be included within the scope of computer-readable transmission media.

[0257] An exemplary environment for implementing various aspects of the present disclosure is illustrated, including a computer (2002) comprising a processing unit (2004), system memory (2006), and a system bus (2008). The system bus (2008) connects system components, including but not limited to system memory (2006), to the processing unit (2004). The processing unit (2004) may be any of a variety of commercially available processors. Dual processors and other multiprocessor architectures may also be utilized as the processing unit (2004).

[0258] The system bus (2008) may be any of several types of bus structures that may be additionally interconnected to a memory bus, a peripheral bus, and a local bus using any of a variety of commercial bus architectures. The system memory (2006) includes read-only memory (ROM) (2010) and random access memory (RAM) (2012). A basic input / output system (BIOS) is stored in non-volatile memory (2010), such as ROM, EPROM, or EEPROM, and contains basic routines that help transfer information between components within the computer (2002), such as during start-up. The RAM (2012) may also include high-speed RAM, such as static RAM, for caching data.

[0259] The computer (2002) also includes an internal hard disk drive (HDD) (2014) (e.g., EIDE, SATA)—which may also be configured for external use within a suitable chassis (not shown), a magnetic floppy disk drive (FDD) (2016) (e.g., for reading from or writing to a removable diskette (2018)), and an optical disk drive (2020) (e.g., for reading from or writing to a CD-ROM disk (2022) or other high-capacity optical media such as a DVD). The hard disk drive (2014), the magnetic disk drive (2016), and the optical disk drive (2020) may be connected to the system bus (2008) by a hard disk drive interface (2024), a magnetic disk drive interface (2026), and an optical drive interface (2028), respectively. The interface (2024) for implementing an external drive includes, for example, at least one or both of Universal Serial Bus (USB) and IEEE 1394 interface technologies.

[0260] These drives and their associated computer-readable media provide nonvolatile storage of data, data structures, computer-executable instructions, and the like. In the case of the computer (2002), the drives and media correspond to storing any data in a suitable digital format. While the description of computer-readable storage media above refers to HDDs, removable magnetic disks, and removable optical media such as CDs or DVDs, those skilled in the art will appreciate that other types of computer-readable storage media, such as zip drives, magnetic cassettes, flash memory cards, cartridges, and the like, may also be used in the exemplary operating environment, and that any such media may contain computer-executable instructions for performing the methods of the present disclosure.

[0261] A number of program modules, including an operating system (2030), one or more application programs (2032), other program modules (2034), and program data (2036), may be stored in the drive and RAM (2012). All or portions of the operating system, applications, modules, and / or data may also be cached in RAM (2012). It will be appreciated that the present disclosure may be implemented in various commercially available operating systems or combinations of operating systems.

[0262] A user may enter commands and information into the computer (2002) via one or more wired / wireless input devices, such as a keyboard (2038) and a pointing device such as a mouse (2040). Other input devices (not shown) may include a microphone, an IR remote control, a joystick, a game pad, a stylus pen, a touch screen, and the like. These and other input devices are often connected to the processing unit (2004) via an input device interface (2042) that is connected to the system bus (2008), but may be connected by other interfaces such as a parallel port, an IEEE 1394 serial port, a game port, a USB port, an IR interface, and the like.

[0263] A monitor (2044) or other type of display device is also connected to the system bus (2008) via an interface, such as a video adapter (2046). In addition to the monitor (2044), the computer typically includes other peripheral output devices (not shown), such as speakers, a printer, and so on.

[0264] The computer (2002) may operate in a networked environment using logical connections to one or more remote computers, such as remote computer(s) (2048), via wired and / or wireless communications. The remote computer(s) (2048) may be a workstation, a server computer, a router, a personal computer, a portable computer, a microprocessor-based entertainment device, a peer device, or other conventional network node, and generally include many or all of the components described for the computer (2002), although for simplicity, only the memory storage device (2050) is shown. The logical connections shown include wired / wireless connections to a local area network (LAN) (2052) and / or a larger network, such as a wide area network (WAN) (2054). Such LAN and WAN networking environments are common in offices and companies and facilitate enterprise-wide computer networks, such as intranets, all of which may be connected to a worldwide computer network, such as the Internet.

[0265] When used in a LAN networking environment, the computer (2002) is connected to a local network (2052) via a wired and / or wireless communication network interface or adapter (2056). The adapter (2056) may facilitate wired or wireless communications to the LAN (2052), which may also include a wireless access point installed therein for communicating with the wireless adapter (2056). When used in a WAN networking environment, the computer (2002) may include a modem (2058), be connected to a communications server on the WAN (2054), or have other means for establishing communications over the WAN (2054), such as via the Internet. The modem (2058), which may be internal or external and wired or wireless, is connected to the system bus (2008) via a serial port interface (2042). In a networked environment, program modules described for the computer (2002) or portions thereof may be stored in a remote memory / storage device (2050). It will be appreciated that the network connections depicted are exemplary and that other means of establishing a communications link between the computers may be used.

[0266] The computer (2002) communicates with any wireless device or object that is configured and operates via wireless communication, such as a printer, a scanner, a desktop and / or portable computer, a portable data assistant (PDA), a communication satellite, any equipment or location associated with a radio-detectable tag, and a telephone. This includes at least Wi-Fi and Bluetooth wireless technologies. Accordingly, the communication may be a predefined structure, as in a conventional network, or may simply be an ad hoc communication between at least two devices.

[0267] Wi-Fi (Wireless Fidelity) enables connections to the Internet and other devices without wires. Wi-Fi is a wireless technology that allows devices, such as computers, to send and receive data anywhere within the coverage area of ​​a base station, both indoors and outdoors, similar to cell phones. Wi-Fi networks use wireless technologies called IEEE 802.11 (a, b, g, etc.) to provide secure, reliable, and high-speed wireless connections. Wi-Fi can be used to connect computers to each other, to the Internet, and to wired networks (using IEEE 802.3 or Ethernet). Wi-Fi networks can operate in the unlicensed 2.4 and 5 GHz radio bands, at data rates of, for example, 11 Mbps (802.11a) or 54 Mbps (802.11b), or in products that include both bands (dual-band).

[0268] Those skilled in the art will appreciate that the various illustrative logical blocks, modules, processors, means, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, various forms of programs or design code (referred to herein, for convenience, as “software”), or a combination of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Those skilled in the art may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

[0269] The various embodiments presented herein can be implemented as a method, apparatus, or article of manufacture using standard programming and / or engineering techniques. The term "article of manufacture" includes a computer program, carrier, or media accessible from any computer-readable device. For example, computer-readable storage media include, but are not limited to, magnetic storage devices (e.g., hard disks, floppy disks, magnetic strips, etc.), optical disks (e.g., CDs, DVDs, etc.), smart cards, and flash memory devices (e.g., EEPROMs, cards, sticks, key drives, etc.). The term "machine-readable medium" includes, but is not limited to, wireless channels and various other media capable of storing, retaining, and / or carrying instructions and / or data.

[0270] It should be understood that the specific order or hierarchy of steps in the presented processes is merely an example of exemplary approaches. It should be understood that the specific order or hierarchy of steps in the processes may be rearranged within the scope of the present disclosure based on design priorities. The appended method claims provide elements of various steps in a sample order, but are not intended to be limited to the specific order or hierarchy presented.

[0271] The description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments without departing from the scope of the present disclosure. Therefore, the present disclosure is not intended to be limited to the embodiments disclosed herein, but is to be construed in the broadest scope consistent with the principles and novel features disclosed herein.

[0272] As described above, the relevant contents have been described in the best form for carrying out the invention.

[0273] It can be used in magnetic resonance-based discrete multiple qubit systems, devices, etc.

Claims

1. In a qubit system based on magnetic resonance, A magnet with a space formed inside; A qubit sample provided in a space formed inside the magnet and including a material capable of quantum state transition; A gradient coil that corresponds to the qubit sample inside the magnet and is provided outside the qubit sample and generates a gradient magnetic field in a space containing the qubit sample inside the magnet; An RF transmitting coil unit disposed between the qubit sample and the gradient magnetic coil inside the magnet, and applying an RF pulse (radio frequency pulse) to the qubit sample and controlling the quantum state of the qubit sample; and An RF receiving coil provided inside the magnet and receiving an RF signal emitted from the qubit sample that has absorbed energy due to the applied RF pulse after the RF pulse ends; including, Qubit system.

2. In paragraph 1, When the above qubit samples are multiple, the multiple qubit samples are spaced apart from each other so as to correspond to predetermined positions inside the magnet, The above gradient magnetic field coil, the RF transmitting coil unit, and the RF receiving coil are provided corresponding to each of the plurality of qubit samples, and One qubit sample corresponds to one gradient coil, one RF transmit coil, and one RF receive coil. Qubit system.

3. In paragraph 1, In the case where there are multiple gradient coils, each of the multiple gradient coils is assigned a unique number identical to the qubit sample provided, and each of the multiple gradient coils applies a discrete gradient field determined in response to the unique number. Qubit system.

4. In paragraph 3, In the case where there are multiple RF transmitting coil units, the multiple RF transmitting coil units apply RF pulses having different resonance frequencies (Larmor frequencies) determined according to the discrete gradient magnetic fields applied from each of the multiple gradient magnetic field coils in response to the unique number. Qubit system.

5. In paragraph 1, In the case where there are multiple RF transmitting coil units, each of the multiple RF transmitting coil units changes the state of the qubit generated from the qubit sample located inside each of the multiple RF transmitting coil units based on the applied RF pulse. Qubit system.

6. In paragraph 1, In the case where there is a difference between the actual magnetic field applied by the magnet in the internal region of the gradient coil and the theoretically predetermined ideal magnetic field, the gradient coil additionally applies a magnetic field that corrects the difference for magnetic field shimming of the magnet. Qubit system.

7. In paragraph 1, The above RF transmitting coil part, A first RF transmitting coil disposed in a first space between the qubit sample and the gradient coil inside the magnet, and applying a first RF pulse (radio frequency pulse) inside the magnet; A second RF transmitting coil disposed in a second space between the qubit sample and the gradient coil inside the magnet, and applying a second RF pulse inside the magnet; and A third RF transmitting coil disposed in a third space between the qubit sample and the gradient coil inside the magnet, and applying a third RF pulse inside the magnet; including, Qubit system.

8. In paragraph 7, The first RF transmitting coil applies the first RF pulse corresponding to the qubit sample to the internal space containing the qubit sample in a direction perpendicular to the magnetic field of the magnet. Qubit system.

9. In paragraph 7, The second RF transmitting coil applies the second RF pulse corresponding to the qubit sample to the internal space containing the qubit sample in a direction perpendicular to the magnetic field of the magnet and the magnetic field applied by the first RF transmitting coil. Qubit system.

10. In paragraph 7, The third RF transmitting coil applies the third RF pulse corresponding to the qubit sample to the internal space containing the qubit sample in a direction parallel to the magnetic field of the magnet. Qubit system.

11. A method for controlling the state of a qubit, A step of applying an RF pulse to a qubit sample provided inside the magnet by an RF transmitting coil unit disposed between a qubit sample provided in a space formed inside the magnet and including a material capable of quantum state transition and a gradient coil provided outside the qubit sample corresponding to the qubit sample inside the magnet; and A step of converting the state of a qubit in the qubit sample based on the applied RF pulse; including, method.

12. A quantum information processing method performed in a processor of a computing device, A step of initializing the state of a qubit of a qubit sample included in the qubit system using a qubit system; A step of converting the state of the qubit by applying an RF pulse through an RF transmitting coil unit provided corresponding to the qubit sample; A step of measuring the state of the converted qubit through an RF receiving coil provided corresponding to the qubit sample; and A step of analyzing the results of measuring the state of the above qubit; Including, The above qubit system is, A magnet with a space formed inside; The qubit sample is provided in a space formed inside the magnet and includes a material capable of quantum state transition; A gradient coil that corresponds to the qubit sample inside the magnet and is provided outside the qubit sample and generates a gradient magnetic field in a space containing the qubit sample inside the magnet; The RF transmitting coil unit is placed between the qubit sample and the gradient magnetic coil inside the magnet, and applies an RF pulse (radio frequency pulse) to the qubit sample and controls the quantum state of the qubit sample; and The RF receiving coil is provided inside the magnet and receives an RF signal emitted after the RF pulse ends from the qubit sample that has absorbed energy due to the applied RF pulse; including, method.

13. In paragraph 12, The step of converting the state of the above qubit is: A step of converting the state of the qubit using an RF pulse corresponding to a rotation operator of a predetermined quantum gate; including, method.

14. In paragraph 12, The step of analyzing the results of measuring the state of the above qubit is: A step of comparing the measured value included in the above result with the expected value corresponding to the rotation operator of the predetermined quantum gate; including, method.

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