Quantum bit detection module and quantum bit control system

Abstract

This quantum bit detection module includes an imaging unit, a processing unit, and an output unit. The imaging unit images an imaging region including a placement position of a quantum bit, and generates imaging data corresponding to the imaging region. The processing unit calculates state information indicating the state of the quantum bit on the basis of the imaging data, the state information having data amount smaller than that of the imaging data. The output unit outputs the state information to the outside of the module.

Description

Quantum bit detection module and quantum bit control system

[0001] The present disclosure relates to qubit detection modules and qubit control systems.

[0002] Quantum computing technology utilizes the properties of quantum superposition to construct quantum bits. Generally, controlling the quantum superposition state requires advanced technology, and the quantum superposition state is known to be very unstable. Therefore, error correction of quantum bits is important in quantum computing.

[0003] Dolev Bluvstein, Harry Levine, Giulia Semeghini, Tout T. Wang, Sepehr Ebadi, Marcin Kalinowski, Alexander Keesling, Nishad Maskara, Hannes Pichler, Markus Greiner, Vladan Vuletic & Mikhail D. Lukin, “A quantum processor based on coherent transport of entangled atom arrays,” Nature, Vol.604, pp.451-471, 2022.

[0004] For example, in a technique for detecting the state of a quantum bit and feedback-controlling the state of the quantum bit in accordance with the detection result, there is a demand for faster detection of the quantum bit state in order to perform feedback control at high speed.

[0005] An object of one aspect of the present disclosure is to provide a quantum bit detection module and a quantum bit control system that can speed up quantum bit state detection.

[0006] A quantum bit detection module according to one aspect includes an imaging unit, a processing unit, and an output unit. The imaging unit captures an image of an imaging area including the placement position of a quantum bit and generates imaging data corresponding to the imaging area. The processing unit calculates state information indicating the state of the quantum bit, the data amount of which is smaller than that of the imaging data, based on the imaging data. The output unit outputs the state information to an external device.

[0007] In the quantum bit detection module, quantum bit state information calculated based on the image data is output to the outside of the module. Therefore, compared to when the quantum bit outputs image data captured by the quantum bit to the outside of the module, the amount of output data is reduced, and quantum bit information can be output at high speed. In other words, quantum bit state detection can be speeded up.

[0008] The state information may be binary data that indicates the state of the quantum bit. Because the state information is expressed as binary data, the amount of data that is output can be made very small.

[0009] The processing unit may set a plurality of target regions smaller than the imaging region within the imaging region, and calculate the state information for each of the plurality of target regions. In this configuration, a single imaging unit can detect a plurality of quantum bits.

[0010] The imaging data may be composed of a plurality of pixel data. The imaging unit may sequentially generate each pixel data constituting the plurality of pixel data. The processing unit may acquire the imaging data by sequentially acquiring the pixel data sequentially generated by the imaging unit, and may calculate state information for one target region when all pixel data for one target region among the plurality of target regions has been acquired during acquisition of the imaging data. In this configuration, data can be output for each target region, allowing quantum bit information to be output without delay.

[0011] The processing unit may have a threshold for determining the state of the quantum bit, and may calculate coordinates of the quantum bit determined based on the threshold as the state information. In this configuration, there is no need to set a target region.

[0012] A quantum bit control system according to one aspect includes the quantum bit detection module and a quantum bit control unit, which controls the state of the quantum bit based on the state information output from the quantum bit detection module.

[0013] The imaging unit may continuously capture images of the imaging area over multiple frames, and the processing unit may calculate the state information for each frame of the captured image data. In this configuration, data can be output for each frame, so that quantum bit information can be output without delay.

[0014] In the above quantum bit control system, quantum bit state information calculated based on imaging data is output from the module to the quantum bit control unit. Therefore, compared to when the quantum bit outputs image data captured by the quantum bit to the quantum bit control unit, the amount of data output is reduced, allowing quantum bit information to be output at high speed. Therefore, quantum bit state detection is accelerated, allowing the quantum bit control unit to quickly control the quantum bit state.

[0015] According to one aspect of the quantum bit detection module and quantum bit control system, quantum bit state detection can be speeded up.

[0016] Fig. 1 is a diagram showing the configuration of a quantum bit control system according to one embodiment. Fig. 2 is a diagram showing a histogram of integrated brightness values ​​created based on a simulation. Fig. 3 is a diagram schematically showing an image captured by a quantum bit detection module. Fig. 4 is a diagram for explaining an example of an output form from the quantum bit detection module to a quantum bit control unit. Fig. 5 is a diagram for explaining another example of an output form from the quantum bit detection module to a quantum bit control unit.

[0017] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. For convenience, substantially identical elements will be denoted by the same reference numerals, and their description may be omitted.

[0018] 1 is a diagram showing a schematic configuration of a quantum bit control system. The quantum bit control system 1 according to this embodiment is a system for controlling the state of a quantum bit that can be in a quantum superposition state. The quantum bit control system 1 can be used, for example, in quantum computer technology that uses neutral atoms trapped by optical tweezers or the like as quantum bits.

[0019] In this embodiment, a quantum bit composed of neutral atoms has at least two different energy levels (internal states). One example of a quantum bit may have at least |↓>, a lower energy level; |↑>, an energy level higher than |↓>; and |e'>, an energy level different from |↑> that excites |↓> and emits fluorescence. For example, a quantum bit can be in a superposition state of |↓> and |↑>. When the quantum bit is in |↓>, if light resonating between |↓> and |e'> strikes it, it absorbs the light, transitions to |e'>, emits fluorescence, and returns to |↓>. Even if the same light is irradiated when the quantum bit is in |↑>, the quantum bit does not transition to |e'>, and no fluorescence is observed. Hereinafter, |↓> may be referred to as the ground level, |↑> as the excited level, and |e'> as the fluorescence level. Light resonating between the ground level and the fluorescence level may be referred to as resonant light.

[0020] As shown in FIG. 1 , an example quantum bit control system 1 includes at least a quantum bit detection module 3, a quantum bit control unit 30, and a module control unit 40. The quantum bit detection module 3 is a device for detecting the state of a quantum bit. In this embodiment, the quantum bit detection module 3 detects the state of the quantum bit by detecting photons emitted from the quantum bit. For example, the photons emitted from the quantum bit may be fluorescence of the quantum bit. In one example, the quantum bit detection module 3 may be an imaging device with low readout noise that allows the number of photoelectrons to be identified.

[0021] The quantum bit detection module 3 includes an imaging unit 10, a processing unit 20, and an output unit 25. The imaging unit 10, the processing unit 20, and the output unit 25 may be housed in a housing 5 that forms the exterior of the module. The imaging unit 10 captures an image of an object and generates imaging data. Note that imaging may mean converting an image of the object into an electrical signal. The imaging unit 10 may be a so-called image sensor, and in one example, may be a CMOS (Complementary Metal-Oxide-Semiconductor) image sensor. The imaging unit 10 may also be a CCD (Charge Coupled Device) image sensor. The imaging unit 10 may also be a SPAD (Single Photon Avalanche Diode) image sensor.

[0022] The imaging unit 10 includes a plurality of pixels 11 and an A / D converter 15. The plurality of pixels 11 are arranged two-dimensionally in rows and columns. Each pixel 11 includes a photodiode (photoelectric conversion element) 12 and an amplifier 13. The photodiode 12 accumulates electrons (photoelectrons) generated by input photons as electric charges. The amplifier 13 converts the electric charges accumulated in the photodiode 12 into voltages and amplifies them. The amplified voltages are transferred to vertical signal lines 16 line by line (row by row) by switching the selection switches 14 of each pixel 11. Each vertical signal line 16 is provided with a CDS (correlated double sampling) circuit 17. The CDS circuit 17 removes noise that varies between pixels and temporarily stores the transferred voltages.

[0023] The A / D converter 15 converts the voltages output from the amplifiers 13 in each of the multiple pixels 11 into digital values. Because the digital values ​​reflect the luminance of the pixel 11, the digital values ​​may be referred to as luminance values ​​in the following description. Note that the luminance values ​​may be synonymous with pixel values. In this embodiment, the A / D converter 15 converts the voltages stored in the CDS circuit 17 into digital values. The converted digital values ​​are output to the processing unit 20. For example, the digital values ​​may be sent to a horizontal signal line (not shown) by switching column selection and output to the processing unit 20. In this way, when photons are input to each pixel 11, the imaging unit 10 outputs a digital value corresponding to the number of input photons to the processing unit 20. Note that the A / D converter 15 may be provided in each pixel 11.

[0024] When the voltage amplified by the amplifier 13 is read out, random read noise is generated within the amplifier 13. If the read noise is large, the accuracy of detecting the state of the quantum bit may decrease. For example, when detecting whether or not a quantum bit is emitting fluorescence, the read noise of the amplifier 13 may increase the digital value, leading to the possibility that it may be determined that fluorescence is being emitted from the quantum bit even though there is no fluorescence from the quantum bit.

[0025] In quantum computing technology, it is expected that quantum bit state detection will be performed repeatedly, and therefore, it is desirable for the accuracy of state detection in a single run to be close to 100%. Therefore, in this embodiment, an imaging unit 10 with low readout noise can be used so that the accuracy of state detection in a single run is 99.9% or higher. For example, the performance of the imaging unit 10 can be evaluated based on image simulations of quantum bits that emit fluorescence and quantum bits that do not emit fluorescence. In one example simulation, the luminance integrated value of a predetermined area (e.g., 6 × 6 pixels) containing the quantum bits is calculated for each of the quantum bits that emit fluorescence and the quantum bits that do not emit fluorescence, and a histogram of the luminance integrated value is created. Then, based on the histogram, a threshold value for distinguishing between the quantum bits that emit fluorescence and the quantum bits that do not emit fluorescence is set, and the luminance integrated value of each quantum bit is determined based on the threshold value.

[0026] FIG. 2 shows the results of a simulation in which the readout noise of the imaging unit 10 is 0.27 e-rms. FIG. 2 is a histogram in which the horizontal axis represents the integrated brightness value of the quantum bit, and the vertical axis represents the frequency of quantum bits with fluorescence and quantum bits without fluorescence. In this example, the exposure time is 20 ms. In the simulation example shown in FIG. 2, the accuracy of distinguishing between quantum bits with fluorescence and quantum bits without fluorescence was 99.98%. Similar simulations using different readout noises showed that when the readout noise was approximately 0.7 e-rms or less, the discrimination accuracy was 99.9% or more. In this embodiment, with the aim of setting the discrimination accuracy to 99.9% or more, a CMOS image sensor with a readout noise of approximately 0.7 e-rms or less is used as the imaging unit 10.

[0027] The imaging unit 10 images an imaging region including the arrangement positions of the quantum bits, and generates imaging data corresponding to the imaging region. The imaging data may be composed of a plurality of pixel data. The plurality of pixel data may be composed of identification data for identifying each pixel 11 and data indicating a luminance value associated with each identification data. An example of the pixel data may be data in which position data (e.g., coordinate data, address, etc.) indicating the position of a pixel is associated with the luminance value of the pixel. Note that, in this embodiment, imaging of the imaging region by the imaging unit 10 may be performed in a state in which each quantum bit is irradiated with resonant light.

[0028] The imaging unit 10 sequentially generates each pixel data constituting a plurality of pixel data and sequentially outputs the generated pixel data to the processing unit 20. For example, in the imaging unit 10, the luminance value of each pixel 11 is sequentially output from the A / D converter 15, and the output luminance value is input to the processing unit 20 together with position data specifying the position of the pixel 11. The order in which the luminance values ​​are output may be determined in advance. Note that the imaging unit 10 may continuously capture an imaging area to be imaged over multiple frames. In this case, the imaging unit 10 sequentially outputs pixel data of each pixel to the processing unit 20 for each frame.

[0029] The processing unit 20 calculates state information indicating the state of the quantum bit based on the imaging data. An example of the processing unit 20 may include one or more field-programmable gate arrays (FPGAs). An FPGA is an integrated circuit whose circuit configuration, such as an array of logic gates, can be programmed, and can quickly execute predetermined calculations (functions) according to the program. The calculation circuit constituting the processing unit 20 is not limited to an FPGA, but may also be composed of an application specific integrated circuit (ASIC), a microcomputer, or the like. In this embodiment, since the processing unit 20 is composed of an FPGA, processing time can be reduced compared to when the processing unit is composed of a CPU, or the like.

[0030] As shown in FIG. 1 , the processing unit 20 includes, as its functional units, a region of interest (ROI) setting unit 21, a filter processing unit 22, and a state determination unit 23. The ROI setting unit 21 sets multiple ROIs within the imaging area, each ROI being smaller than the imaging area. FIG. 3 is a schematic diagram showing an image captured by the quantum bit detection module 3. In FIG. 3 , quantum bits 105 that emit fluorescence during imaging are shown in black, and the background is shown in white. The position and state of the quantum bits 105 are controlled by the quantum bit control unit 30. The quantum bits 105 are positioned at predetermined positions using, for example, an atom trapping technique such as optical tweezers. Note that other known techniques may be used to position the quantum bits 105 at predetermined positions in space.

[0031] In the example of the imaging region 100 shown in FIG. 3 , atoms forming quantum bits 105 are arranged at positions spaced apart from each other in an 8×8 grid. In the following description, the vertical direction (height direction) when viewed from the front of the drawing may be referred to as the X direction, and the horizontal direction as the Y direction. The ROI setting unit 21 sets multiple ROIs 101 corresponding to the multiple quantum bits 105 within the imaging region 100. In FIG. 3 , the set ROIs 101 are indicated by dashed lines. As shown in the figure, the ROIs 101 in the example surround each quantum bit 105 in a rectangular shape. The size of the ROI 101 may be any size that can surround the quantum bits 105. For example, if the quantum bit 105 has approximately 1×1 to 4×4 pixels, the ROI 101 may have approximately 1×1 to 6×6 pixels. The number of pixels corresponding to the quantum bits 105 and the ROI 101 is merely an example and is not limited thereto.

[0032] The filter processing unit 22 performs filtering on the imaging data captured by the imaging unit 10. The filtering may be, for example, threshold processing (static or dynamic), Gaussian fitting, pattern matching, Fourier transform, or the like. The filtering may also be processing based on machine learning. By filtering the imaging data, the accuracy of processing by the state determination unit 23 can be improved. The filtering may be performed for each ROI 101, or may be performed on the entire imaging data.

[0033] The state determination unit 23 detects the state of the quantum bits 105 in the imaging region 100. In this embodiment, the state determination unit 23 calculates state information of the quantum bits 105 in each of the multiple ROIs 101 set by the ROI setting unit 21. In one example, the state information may be binary data indicating the state of the quantum bit. For example, the state determination unit 23 may have a brightness value threshold for determining the state of the quantum bit. The state determination unit 23 may acquire the state information by comparing the threshold with the brightness value in the ROI.

[0034] This threshold may be determined based on prior experiments or the like using a method similar to that used in the simulation described above. That is, with quantum bits 105 arranged in imaging region 100, the luminance integrated value within ROI 101 is calculated, and a threshold for distinguishing between quantum bits 105 that emit fluorescence and quantum bits 105 that do not emit fluorescence is derived from a histogram created based on the luminance integrated value. The quantum bits 105 that emit fluorescence are quantum bits whose internal state is in the ground level and emit fluorescence when irradiated with light that transitions to the fluorescence level. The quantum bits 105 that do not emit fluorescence are quantum bits whose internal state is in the excited level.

[0035] The state determination unit 23 may calculate an integrated luminance value by accumulating the luminance values ​​of all pixels 11 within the ROI 101 to be determined, and based on a comparison between the integrated luminance value and a threshold, determine that the quantum bit 105 is in the ground state if the integrated luminance value is greater than the threshold, and determine that the quantum bit 105 is in the excited state if the integrated luminance value is equal to or less than the threshold. The state determination unit 23 may associate the determination result with identification data for the ROI 101. The determination result may be binary data indicating the presence or absence of fluorescence, i.e., binary data indicating the ground state or the excited state. The identification data for the ROI 101 may be address data assigned to each ROI 101, or may be position data of a reference pixel within each ROI 101. The reference pixel may be a predetermined pixel within the ROI (e.g., the pixel in the upper left corner) or a pixel located at the center of the quantum bit 105 in each ROI 101.

[0036] In this embodiment, pixel data sequentially generated by the imaging unit 10 is sequentially input to the processing unit 20. Even while imaging data within the imaging region 100 is being acquired, the state determination unit 23 may calculate state information for one ROI 101 when all pixel data for that ROI 101 has been acquired. For example, each time the state determination unit 23 acquires pixel data for a pixel within the ROI 101, it may sequentially accumulate the luminance value of the pixel data.

[0037] When imaging data spanning multiple frames is output from the imaging unit 10 to the processing unit 20, the processing unit 20 may calculate the status information for each frame of the imaging data. That is, the integrated value of the luminance values ​​of the pixels in the ROI 101 may be an integrated value for one frame, rather than an integrated value spanning multiple frames.

[0038] The output unit 25 outputs state information indicating the state of the quantum bit 105 calculated by the processing unit 20 to the outside of the quantum bit detection module 3. The output unit 25 of this embodiment outputs the state information to the quantum bit control unit 30. For example, the output unit 25 of the quantum bit detection module 3 may be a serial I / O such as a USB (Universal Serial Bus). FIG. 4 is a conceptual diagram for explaining an example of an output form from the quantum bit detection module 3 to the quantum bit control unit 30. As shown in the figure, in one example, state information of multiple ROIs 101 may be output to the quantum bit control unit 30 via a single output unit 25 provided in the quantum bit detection module 3. Binary data including state information corresponding to each ROI 101 may be sequentially output from the output unit 25. In the illustrated example, the output data is composed of two values: "1" indicating that fluorescence from the quantum bit has been detected and "0" indicating that fluorescence has not been detected. In other words, the binary data output from the output unit 25 may be data in which "1" indicating that the quantum bit is in the ground state and "0" indicating that the quantum bit is in the excited state are arranged in the order of the arrangement of the ROI 101.

[0039] The quantum bit control unit 30 controls the state of the quantum bit 105 based on the state information input from the quantum bit detection module 3. The quantum bit control unit 30 may include a processing circuit to which the state information is input and a laser irradiation system controlled by the processing circuit. The laser irradiation system may be configured as a device separate from the quantum bit control unit 30. For example, the processing circuit of the quantum bit control unit 30 may be configured to include an FPGA. The quantum bit control unit 30 has correct information on what state the quantum bit should be in and compares this correct information with the state information input from the quantum bit detection module 3. If a quantum bit is determined to be in an incorrect state as a result of comparing the correct information with the state information, the quantum bit control unit 30 corrects the state of the quantum bit. The correction of the quantum bit state can be performed by controlling the state of laser irradiation on the quantum bit.

[0040] For example, if a quantum bit that should be at an excited state is at the ground state and emitting fluorescence, the quantum bit control unit 30 may irradiate the quantum bit with a laser to bring it to the excited state. Thus, error correction (state control) by laser irradiation may be a technique for manipulating a quantum state by irradiating a specific quantum bit with a laser. Furthermore, the error correction technique may be a technique for manipulating the arrangement of quantum bits by controlling the intensity, phase, etc. of the laser irradiated to the quantum bit using a spatial light modulator (SLN), an acousto-optical modulator (AOM), or the like. Note that, for example, assuming that all quantum bits 105 are controlled to the ground state, if there is an ROI 101 in which no fluorescence is detected, the processing unit 20 or the quantum bit control unit 30 may determine that the quantum bit in that ROI 101 is not trapped in the position where it should be. In this case, the quantum bit control unit 30 may rearrange the quantum bits by optical trap control using a laser.

[0041] The module control unit 40 controls the operation of the quantum bit detection module 3. The module control unit 40 is physically configured to include storage devices such as RAM and ROM, a processor (arithmetic circuit) such as a CPU, a communication interface, etc. Examples of such module control unit 40 include a personal computer, a cloud server, a smart device (smartphone, tablet terminal, etc.), a microcomputer, and an FPGA. A display device such as a display, and an input device such as a keyboard and a mouse can be connected to the module control unit 40.

[0042] The module control unit 40 is connected to the processing unit 20 via an output terminal different from the output unit 25 provided in the quantum bit detection module 3 so as to be able to communicate with each other. The module control unit 40 may acquire image data from the processing unit 20 and display an image of the imaging region 100 on the display. In one example, the module control unit 40 may be used to control the setting of the ROI 101. For example, a user may specify an ROI by operating a mouse while the image of the imaging region 100 is displayed on the display. As one example, when the mouse is dragged on the display, the module control unit 40 may recognize a rectangular frame having a diagonal line connecting the start point and end point of the drag as the ROI. Furthermore, when the mouse is clicked on the display, the module control unit 40 may recognize the clicked coordinates as the center pixel of the ROI and recognize certain surrounding pixels including the center pixel as the ROI.

[0043] The module control unit 40 may also determine the setting position of the quantum bit within the imaging area by automatically recognizing image data of the quantum bit. In this case, the module control unit 40 may form a grid with intersections at the positions of the recognized quantum bits, and form an ROI with the grid intersections as its center.

[0044] The user may also specify an ROI by inputting position data (coordinate data) of the ROI. The position data may be numerical data input directly by the user or an external table-format file. The position data may be composed of coordinates of a predetermined reference point of the ROI, data determining the vertical width of the ROI, and data determining the horizontal width of the ROI. The coordinates of the reference point may be composed of an offset distance (offset X) from the upper left corner of the image to the right (X direction) and an offset distance (offset Y) from the upper left corner of the image to the bottom (Y direction). The position data may also be the coordinates of two diagonal points of a rectangular ROI. In a mode in which position data is input, image data of the imaging area does not need to be displayed on the display.

[0045] The data specified by the user may also be the position data of a specific ROI, the step and number in the X direction, and the step and number in the Y direction. In this case, all ROIs will be formed with the same size. Similarly, when forming ROIs with the same size, the reference coordinates of each ROI (e.g., the coordinates of the upper left corner) and the vertical and horizontal distances common to all ROIs may be specified.

[0046] As described above, the example quantum bit detection module 3 includes the imaging unit 10, the processing unit 20, and the output unit 25. The imaging unit 10 captures an image of the imaging region 100 that includes the arrangement position of the quantum bit 105, and generates imaging data corresponding to the imaging region 100. The processing unit 20 calculates state information indicating the state of the quantum bit 105 based on the imaging data. The output unit 25 outputs the state information to the outside of the module.

[0047] For example, in a system for detecting the state of a quantum bit, when image data of the quantum bit is transferred to an external control system, the large amount of data transferred can make it difficult to increase the speed. This tendency is particularly pronounced in systems that simultaneously detect the states of a large number of quantum bits. In the quantum bit detection module 3, the state information of the quantum bit 105 calculated by the processing unit 20 based on the image data is output to the outside of the module. Therefore, compared to when image data of the quantum bit 105 is directly output to the outside of the module, the amount of output data is reduced, and information about the quantum bit 105 can be output at a high speed. In other words, the state detection of the quantum bit 105 can be accelerated. Note that, by generating the quantum bit state information within the quantum bit detection module 3 that images the quantum bit in this way, the process of analyzing the quantum bit state in the quantum bit control unit 30 can be eliminated.

[0048] The state information may be binary data that indicates the state of the quantum bit 105. Because the state information is expressed as binary data, the amount of data output to the outside is extremely small, and the state information can be output at high speed.

[0049] The imaging unit 10 may continuously capture images of the imaging region 100 over multiple frames, and the processing unit 20 may calculate the state information for each frame of the captured image data. In this configuration, data can be output for each frame, so that information about the quantum bit 105 can be output without delay.

[0050] The processing unit 20 may set a plurality of ROIs 101 smaller than the imaging region 100 within the imaging region 100, and calculate state information for each of the plurality of ROIs 101. In this configuration, a single imaging unit 10 can detect a plurality of quantum bits 105.

[0051] The imaging data may be composed of a plurality of pixel data. The imaging unit 10 may sequentially generate each pixel data constituting the plurality of pixel data. The processing unit 20 may acquire the imaging data by sequentially acquiring the pixel data sequentially generated by the imaging unit 10, and may calculate state information for one ROI 101 when all pixel data for one ROI 101 among the plurality of ROIs 101 has been acquired during acquisition of the imaging data. In this configuration, state information can be output for each ROI, so information on the quantum bit 105 can be output without delay.

[0052] A quantum bit control system 1 according to one aspect includes the quantum bit detection module 3 and a quantum bit control unit 30. The quantum bit control unit 30 controls the state of the quantum bit based on the state information output from the quantum bit detection module 3.

[0053] In the above-described quantum bit control system 1, quantum bit state information calculated based on imaging data is output from the module to the quantum bit control unit 30. Therefore, the amount of data output is reduced compared to when the quantum bit outputs image data captured by the quantum bit to the quantum bit control unit 30, and quantum bit information can be output at high speed. Therefore, quantum bit state detection is accelerated, and quantum bit state control by the quantum bit control unit 30 is executed at high speed.

[0054] Although the embodiment has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment.

[0055] 5 is a diagram illustrating a modified example of the form of output from the quantum bit detection module 3 to the quantum bit control unit 30. In this modified example, the quantum bit detection module 3 has a plurality of output units 25 corresponding to the plurality of ROIs 101, respectively. When the processing unit 20 detects state information of any one of the ROIs 101, the state information of that ROI 101 is output to the quantum bit control unit 30 via the output unit 25 corresponding to that ROI 101.

[0056] Furthermore, in the above embodiment, an example in which ROI 101 is rectangular has been shown, but ROI 101 is not limited to being rectangular. ROI may be any shape in plan view having a certain area that can contain quantum bits 105, such as a circle or a polygonal shape other than a rectangle. For example, if the ROI is circular, the user may specify the coordinates of the center position of the ROI and the diameter or radius of the ROI.

[0057] Although the state information is binary data indicating the state of the quantum bit, the state information is not limited to this. For example, the state information may be a luminance value (integrated luminance value) detected in the quantum bit or the ROI.

[0058] Furthermore, in the above embodiment, the processing unit 20 sets multiple ROIs in the imaging region 100 and outputs state information for each ROI. However, ROIs do not necessarily need to be set. For example, the processing unit 20 may have a threshold for determining the state of the quantum bit 105 and may calculate the coordinates of the quantum bit 105 determined based on the threshold as state information. As an example, the processing unit 20 may acquire image data of the imaging region and obtain the coordinates of the quantum bit based on a threshold for determining the fluorescence of the quantum bit. For example, the processing unit 20 may binarize the image data into pixels where fluorescence is detected and pixels where fluorescence is not detected based on the threshold, and obtain the center of gravity, center position, etc. of the pixel region where fluorescence is detected as the quantum bit coordinates. As a result, the processing unit 20 calculates data indicating the coordinates of the quantum bit emitting fluorescence as quantum bit state information. In this case, the quantum bit control unit 30 may have the layout coordinates of the quantum bit in advance. The quantum bit control unit 30 may determine the state of each quantum bit by comparing the layout coordinates with the state information output from the processing unit 20. For example, when coordinate data is input from the processing unit 20, the quantum bit control unit 30 may determine that a quantum bit located at coordinates included in the data is in the ground state, and that a quantum bit located at coordinates not included in the data is in the excited state. Note that, for example, a method such as pattern matching may be used to detect the coordinates.

[0059] Furthermore, although an example has been given in which a neutral atom is used as a quantum bit, the quantum bit may be any atom whose state can be controlled by an external operation, for example, an ionized atom.

[0060] The embodiments of the present disclosure can be expressed as follows. [1] A module for detecting a state of a quantum bit, comprising: an imaging unit that images an imaging area including an arrangement position of the quantum bit and generates imaging data corresponding to the imaging area; a processing unit that calculates state information indicating the state of the quantum bit, the data amount of which is smaller than the imaging data, based on the imaging data; and an output unit that outputs the state information to the outside of the module. [2] The quantum bit detection module according to [1], wherein the state information is binary data indicating the state of the quantum bit. [3] The quantum bit detection module according to either [1] or [2], wherein the processing unit sets a plurality of target areas within the imaging area that are smaller than the imaging area, and calculates the state information in each of the plurality of target areas. [4] The quantum bit detection module of [5], wherein the imaging data is composed of a plurality of pixel data, the imaging unit sequentially generates each pixel data constituting the plurality of pixel data, the processing unit acquires the imaging data by sequentially acquiring the pixel data sequentially generated by the imaging unit, and calculates the state information for one target region among the plurality of target regions when all pixel data for the one target region has been acquired during acquisition of the imaging data. [5] The quantum bit detection module of [1], wherein the processing unit has a threshold for determining the state of the quantum bit, and calculates, as the state information, coordinates of the quantum bit determined based on the threshold. [6] The quantum bit detection module of any of [1] to [5], wherein the imaging unit continuously images the imaging region over a plurality of frames, and the processing unit calculates the state information for each frame of the imaging data. [7] A quantum bit control system comprising the quantum bit detection module of any of [1] to [6], and a quantum bit control unit that controls the state of the quantum bit based on the state information output from the quantum bit detection module.

[0061] 1... quantum bit control system, 3... quantum bit detection module, 10... imaging unit, 20... processing unit, 25... output unit, 30... quantum bit control unit.

Claims

1. A quantum bit detection module for detecting a state of a quantum bit, comprising: an imaging unit that images an imaging area including a position of the quantum bit and generates imaging data corresponding to the imaging area; a processing unit that calculates state information indicating the state of the quantum bit, the data amount of which is smaller than that of the imaging data, based on the imaging data; and an output unit that outputs the state information to the outside of the module.

2. The quantum bit detection module of claim 1, wherein the state information is binary data indicating the state of the quantum bit.

3. A quantum bit detection module as described in claim 1 or 2, wherein the processing unit sets a plurality of target areas smaller than the imaging area within the imaging area, and calculates the state information in each of the plurality of target areas.

4. The quantum bit detection module of claim 3, wherein the imaging data is composed of a plurality of pixel data, the imaging unit sequentially generates each of the pixel data constituting the plurality of pixel data, and the processing unit acquires the imaging data by sequentially acquiring the pixel data sequentially generated by the imaging unit, and calculates the state information for one target area when all pixel data for the one target area among the plurality of target areas has been acquired during acquisition of the imaging data.

5. The quantum bit detection module of claim 1, wherein the processing unit has a threshold for determining the state of the quantum bit, and calculates the coordinates of the quantum bit determined based on the threshold as the state information.

6. The quantum bit detection module according to claim 1, wherein the imaging unit continuously images the imaging area over a plurality of frames, and the processing unit calculates the state information for each frame of the imaging data.

7. A quantum bit control system comprising: the quantum bit detection module according to claim 1; and a quantum bit control unit that controls the state of the quantum bit based on the state information output from the quantum bit detection module.

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