Multi-purpose light collection method and apparatus for remotely entangled multi-core architecture atomic quantum computer

Abstract

Aspects of the present disclosure generally relate to systems and methods for implementation and / or operation of a quantum information processing (QIP) system, more specifically, the invention relates to a method for receiving a readout beam associated with a state of a first qubit of an array trapping ions, receiving an interconnection beam configured to entangle a second qubit of the array with an external qubit of an external array, receiving an addressing beam from an addressing unit configured to control a state of a third qubit of the array, the addressing beam from the addressing unit is directed to the third qubit via at least one switch, and the readout beam is directed to a photodetector via the at least one switch, and a system and method of directing the interconnection beam via the at least one switch to an interconnection unit optically coupled with the external array.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Application Serial No. 63 / 366,874, filed on June 23, 2022, the entirety of which is incorporated herein by reference. Technical Field

[0003] Aspects of the present disclosure generally relate to systems and methods for implementing and / or operating a quantum information processing (QIP) system, and more particularly, to the operation of multiple QIP systems. Background Art

[0004] Trapped atoms are one of the main implementation methods for quantum information processing or quantum computing. Atom-based qubits can be used as quantum gates in quantum memories, quantum computers and simulators, and as nodes in quantum communication networks. Qubits based on trapped atomic ions have a rare combination of properties. For example, qubits based on trapped atomic ions have very good coherence properties, can be prepared and measured with an efficiency close to 100%, and can be easily entangled with each other by regulating their Coulomb interactions with suitable external control fields (such as light fields or microwave fields). These properties make atom-based qubits attractive for expanding quantum operations such as quantum computing or quantum simulation.

[0005] Therefore, it is very important to develop new techniques to improve the design, fabrication, implementation and / or control of different QIP systems used as quantum computers or quantum simulators, especially for those dealing with atomic qubit-based operations. Summary of the invention

[0006] A simplified summary of one or more aspects is given below to provide a basic understanding of these aspects. This summary is not an extensive overview of all contemplated aspects, and is neither intended to identify the key or important elements of all aspects, nor to describe the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to a more detailed description presented later.

[0007] In some aspects of the present disclosure, switches / interconnects may be used to enable remote entanglement of qubits. An interconnect beam used to entangle a remote qubit may traverse substantially the same path as a readout beam and / or an addressing beam. A switch / interconnect may be used to separate the readout beam, the interconnect beam, and / or the addressing beam and direct them to different optical components. The readout beam may be directed to a readout device. The interconnect beam may be directed to a remote qubit.

[0008] Aspects of the present disclosure include systems and methods for receiving a readout beam associated with a state of a first qubit of an array of trapped ions; receiving an interconnection beam configured to entangle a second qubit of the array with an external qubit of an external array; receiving an addressing beam configured to control a state of a third qubit of the array from an addressing unit; directing the addressing beam from the addressing unit to the third qubit via at least one switch; directing the readout beam via the at least one switch to a photodetector; and directing the interconnection beam via the at least one switch to an interconnection unit optically coupled to the external array.

[0009] To achieve the above and related ends, the one or more aspects include the features fully described below and particularly pointed out in the claims. The following description and the accompanying drawings set forth in detail certain illustrative features of the one or more aspects. However, these features are merely indicative of some of the many ways in which the principles of the various aspects may be employed, and the present description is intended to include all such aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The various aspects of the disclosure will be described below in conjunction with the accompanying drawings, which are provided only for the purpose of illustrating and not for limiting the various aspects of the disclosure, wherein like reference numerals represent like elements, and wherein:

[0011] Figure 1 Shown are views of atomic ions in a linear crystal or chain in accordance with aspects of the present disclosure.

[0012] Figure 2 An example of a quantum information processing (QIP) system according to aspects of the present disclosure is shown.

[0013] Figure 3 An example of a computer device according to aspects of the present disclosure is shown.

[0014] Figure 4 An example of a QPU network according to aspects of the present disclosure is shown.

[0015] Figure 5 An example of a viewport according to some aspects of the present disclosure is shown.

[0016] Figure 6A-6C An example configuration for trapping ions in a QPU according to some aspects of the present disclosure is shown.

[0017] Figure 7 Examples of the states of trapped ions of a QPU according to aspects of the present disclosure are shown.

[0018] Figure 8 An example of a system supporting interconnection according to aspects of the present disclosure is shown.

[0019] Fig. 9 A functional diagram of a system supporting interconnection according to aspects of the present disclosure is shown.

[0020] Figure 10A-10C Example schemes for multiplexing light beams according to aspects of the present disclosure are shown.

[0021] Fig.11 Examples of overlapping of adjacent atoms according to aspects of the present disclosure are shown.

[0022] Fig.12 Examples of atomic configurations and waveguide spacings according to aspects of the present disclosure are shown.

[0023] Fig.13 An operational example of routing interconnect beams by a second switch is shown in accordance with aspects of the present disclosure.

[0024] Figure 14A-14B Exemplary implementations of interferometers and / or beam splitters as part of entanglement generation according to aspects of the present disclosure are shown.

[0025] Fig.15 A method of achieving long-range entanglement of multiple QPUs according to aspects of the present disclosure is shown. DETAILED DESCRIPTION

[0026] The detailed description given below in conjunction with the accompanying drawings is intended as a description of various configurations or embodiments and is not intended to represent the only configuration or embodiment that can practice the concepts described herein. This detailed description includes specific details for providing a thorough understanding of various concepts. However, it is apparent to those skilled in the art that these concepts can be practiced without the situation of these specific details or with the situation of the variant of these specific details. In some cases, known components are shown in the form of block diagrams, and some boxes can represent one or more known components.

[0027] Quantum computing (QC) is a method of processing information that utilizes quantum two-level systems, or quantum bits (qubits), as the fundamental unit of information storage. QC also exploits the entanglement between qubits generated locally in many QC platforms to perform computations with fewer resources (e.g., computation time, number of bits, etc.) than classical computing schemes. In a quantum computer, a quantum processing unit (QPU) can be allocated by subsets of qubits between which entanglement can be deterministically generated, allowing quantum gates to be directly executed. Building large QPUs can be a challenging task, with many technical barriers that are unique to the specific quantum system used as a computing platform. Another approach for scaling QC is to interconnect multiple smaller QPUs, each with limited computational power, but when linked, having the computational power of a much larger device.

[0028] The technical challenges of scaling QC are closely tied to the computing platform in which the qubits are encoded. In atomic systems, qubits are essentially identical, and many systems naturally have good connectivity between qubits within the QPU. The main difficulty in scaling these platforms is the technical overhead involved in increasing the size of the QPU while maintaining QPU performance, most notably gate fidelity and gate time. Therefore, what is lacking is a technical implementation that makes QC in atomic systems feasible.

[0029] A modular approach to scaling QC in atomic systems avoids the need for a large number of qubits in a single QPU by connecting smaller QPUs. One exemplary aspect includes utilizing optical interconnects, also known as photonic links, to herald entanglement between distant QPUs.

[0030] Exemplary aspects of the present disclosure include optical hardware configured to implement a multi-QPU approach to atom QC. Three basic operations in the multi-QPU approach to atom QC can exploit high numerical aperture optical access to atoms, including one or more of: (1) individual addressing of optical qubits, (2) spatially resolved qubit readout, and / or (3) fluorescence collection for predicting long-range entanglement in optical interconnects. Given the limited optical access to atoms within a vacuum chamber, it may be advantageous to perform all three operations through a single high numerical aperture viewport.

[0031] Aspects of the present disclosure include the design of an optical device that enables the optical paths of the above operations while maintaining the independence of the degrees of freedom required for their function (e.g., wavelength, polarization). Another aspect includes several approaches for separating these optical paths that utilize the temporal, spatial, or frequency degrees of freedom of light.

[0032] Combination Figure 1-Figure 15 The solution to the above problem is explained in more detail, Figure 1-Figure 3 A general configuration of a QIP system or a quantum computer, more specifically, a general configuration of an atom-based QIP system or a quantum computer is provided.

[0033] Shown below Figure 1 shows the use of a well (the well can be Figure 2 100 of trapping a plurality of atomic ions 106 (e.g., atomic ions 106a, 106b, ..., 106c, and 106d) in a linear crystal or chain 110 (in a vacuum chamber as shown). The trap may be referred to as an ion trap. The ion trap shown may be constructed or fabricated on a semiconductor substrate, a dielectric substrate, or a glass die or wafer (also referred to as a glass substrate). The atomic ions 106 may be provided to the trap as atomic species for ionization and confinement to the chain 110.

[0034] exist Figure 1 In the example shown, the trap includes electrodes for trapping or confining a plurality of atomic ions in the chain 110, which are cooled to near rest by laser. The number of trapped atomic ions (N) may be configurable, and more or fewer atomic ions may be trapped. The atomic ions may be, for example, ytterbium ions (e.g. 171 Yb + ions). Use tuning to 171 Yb + Resonant laser (optical) radiation illuminates the atomic ions and images the fluorescence of the atomic ions onto a camera or other type of detection device. In this example, the atomic ions can be separated from each other by about 5 microns (μm), although the spacing may be less than or greater than 5μm. The spacing of the atomic ions is determined by the balance between external restraining forces and Coulomb repulsion and does not need to be uniform. In addition, in addition to atomic ytterbium ions, neutral atoms, Rydberg atoms, different atomic ions or different types of atomic ions can also be used. The trap can be a linear RF Paul trap, but other types of restraints can also be used, including optical restraints. Therefore, the restraint device can be based on different technologies and can hold ions and / or neutral atoms. For example, an ion trap is an example of such a restraint device. The ion trap can be, for example, a surface trap.

[0035] Shown below Figure 2 is a block diagram illustrating an example of a QIP system 200 according to various aspects of the present disclosure. The QIP system 200 may also be referred to as a quantum computing system, a quantum computer, a computer device, a trapped ion system, etc. The QIP system 200 may be part of a hybrid computing system in which the QIP system 200 is used to perform quantum computations and operations and the hybrid computing system also includes a classical computer that performs classical computations and operations.

[0036] Figure 2 2 is a general purpose controller 205 configured to perform various control operations of the QIP system 200. Instructions for the control operations may be stored in a memory (not shown) in the general purpose controller 205 and may be updated over time via a communication interface (not shown). Although the general purpose controller 205 is shown as being separate from the QIP system 200, the general purpose controller 205 may be integrated with or become part of the QIP system 200. The general purpose controller 205 may include an automation and calibration controller 280 configured to perform various calibration, testing, and automation operations associated with the QIP system 200.

[0037] The QIP system 200 may include an algorithm component 210 that may operate with other parts of the QIP system to perform quantum algorithms or quantum operations, including single-qubit operations and / or multi-qubit operations (e.g., two-qubit operations) and combined stacks or sequences of extended quantum computations. Thus, the algorithm component 210 may provide instructions to various components of the QIP system 200 (e.g., to the optical and trap controllers 220) to enable implementation of the quantum algorithm or quantum operation. The algorithm component 210 may receive information generated by implementation of the quantum algorithm or quantum operation and may process the information and / or transmit the information to another component of the QIP system 200 or to another device for further processing.

[0038] The QIP system 200 may include an optics and trap controller 220 that controls various aspects of a trap 270 in a chamber 250, including generating signals that control the trap 270 and controlling the operation of lasers and optical systems that provide a light beam that interacts with atoms or ions in the trap. When used to confine or trap ions, the trap 270 may be referred to as an ion trap. However, the trap 270 may also be used to trap neutral atoms, Rydberg atoms, different atomic ions, or different types of atomic ions. The lasers and optical systems may be at least partially located in the optics and trap controller 220 and / or in the chamber 250. For example, the optical system within the chamber 250 may refer to an optical component or an optical assembly.

[0039] The QIP system 200 may include an imaging system 230. The imaging system 230 may include a high-resolution imager (e.g., a CCD camera) or other type of detection device (e.g., a photomultiplier tube or PMT) for monitoring the atomic ions while they are provided to the trap 270 and / or after they are provided to the trap 270. In one aspect, the imaging system 230 may be implemented separately from the optics and trap controller 220, however, the use of fluorescence to detect, identify, and label the atomic ions by using image processing algorithms may require coordination with the optics and trap controller 220.

[0040] In addition to the above components, the QIP system 200 may also include a source 260 that provides atomic species (e.g., a plume or flux of neutral atoms) to a chamber 250 having a trap 270. When atomic ions are the basis of quantum operations, the trap 270 confines the atomic species after ionization (e.g., photoionization). The trap 270 can be part of a processor or processing portion of the QIP system 200. That is, the trap 270 can be considered to be at the core of the processing operation of the QIP system 200 because it holds the atom-based qubits used to perform quantum operations or simulations. At least a portion of the source 260 can be implemented separately from the chamber 250.

[0041] It should be understood that for ease of understanding, Figure 2The various components of the QIP system 200 described in the description are described at a high level. Such components may include one or more sub-components, the details of which may be provided below as needed to better understand certain aspects of the present disclosure.

[0042] Now refer to the following Figure 3 , shows an example of a computer system or device 300 according to various aspects of the present disclosure. For example, computer device 300 can represent a single computing device, multiple computing devices, or a distributed computing system. Computer device 300 can be configured as a quantum computer (e.g., a QIP system), a classical computer, or to perform a combination of quantum and classical computing functions, sometimes referred to as hybrid functions or operations. For example, computer device 300 can be used to process information using quantum algorithms, classical computer data processing operations, or a combination of both. In some cases, the results of one set of operations (e.g., quantum algorithms) are shared with another set of operations (e.g., classical computer data processing). A general example of a computer device 300 implemented as a QIP system capable of performing quantum computations and simulations is, for example, Figure 2 The QIP system 200 shown in FIG.

[0043] The computer device 300 may include a processor 310 for performing processing functions associated with one or more features described herein. The processor 310 may include a single group or multiple groups of processors or a multi-core processor. In addition, the processor 310 may be implemented as an integrated processing system and / or a distributed processing system. The processor 310 may include one or more central processing units (CPUs) 310a, one or more graphics processing units (GPUs) 310b, one or more quantum processing units (QPUs) 310c, one or more intelligent processing units (IPUs) 310d (e.g., artificial intelligence or AI processors), or a combination of some or all of these types of processors. In one aspect, the processor 310 may refer to a general-purpose processor of the computer device 300, which may also include an additional processor 310 for performing more specific functions (e.g., including functions for controlling the operation of the computer device 300).

[0044] The computer device 300 may include a memory 320 for storing instructions executable by the processor 310 to perform operations. The memory 320 may also store data for processing by the processor 310 and / or data generated by the processing of the processor 310. In one embodiment, for example, the memory 320 may correspond to a computer-readable storage medium storing code or instructions for performing one or more functions or operations. As with the processor 310, the memory 320 may refer to a general memory of the computer device 300, which may also include additional memory 320 for storing instructions and / or data for more specific functions.

[0045] It should be understood that the processor 310 and the memory 320 may be used in conjunction with various operations including, but not limited to, computation, calculation, simulation, control, calibration, system management, and other operations of the computer device 300, including any methods or processes described herein.

[0046] In addition, the computer device 300 may include a communication component 330 for establishing and maintaining communications with one or more parties using hardware, software, and services. The communication component 330 may also be used to carry communications between components on the computer device 300, and between the computer device 300 and external devices (such as devices located on a communication network and / or devices connected serially or locally to the computer device 300). For example, the communication component 330 may include one or more buses, and may further include a transmission chain component and a reception chain component associated with a transmitter and a receiver, respectively, operable to interface with an external device. The communication component 330 may be used to receive update information for the operation or function of the computer device 300.

[0047] In addition, the computer device 300 may include a data store 340, which may be any suitable combination of hardware and / or software that provides mass storage of information, databases, and programs used in conjunction with the operation of the computer device 300 and / or any of the methods or processes described herein. For example, the data store 340 may be a data repository for an operating system 360 (e.g., a classical OS or a quantum OS, or both). In one embodiment, the data store 340 may include a memory 320. In one embodiment, the processor 310 may execute the operating system 360 and / or applications or programs, and the memory 320 or the data store 340 may store them.

[0048] The computer device 300 may also include a user interface component 350, which is configured to receive input from a user of the computer device 300, and is further configured to generate output to present to the user or provide to different systems (directly or indirectly). The user interface component 350 may include one or more input devices, including but not limited to a keyboard, a numeric keypad, a mouse, a touch-sensitive display, a digitizer, a navigation key, a function key, a microphone, a voice recognition component, any other mechanism capable of receiving input from a user, or any combination thereof. In addition, the user interface component 350 may include one or more output devices, including but not limited to a display, a speaker, a tactile feedback mechanism, a printer, any other mechanism capable of presenting output to a user, or any combination thereof. In one embodiment, the user interface component 350 may send and / or receive messages corresponding to the operation of the operating system 360. When the computer device 300 is implemented as a part of a cloud-based infrastructure solution, the user interface component 350 may be used to allow a user of the cloud-based infrastructure solution to interact remotely with the computer device 300.

[0049] Combination Figure 1-Figure 3 In the system described in, aspects of the present disclosure include an interconnect system configured to entwine together a plurality of QPUs that are remotely arranged from each other. Figure 2-Figure 3 The system described in can be used to control various aspects of the interconnect system as described below.

[0050] Figure 4 An example of a QPU network 400 according to aspects of the present disclosure is shown. Individual atoms confined in a single or multi-dimensional array within a vacuum chamber can provide a promising platform for QC that is also applicable to interconnected QPU networks. The proposal of interconnected atomic qubits probabilistically predicts entanglement between "remote" atoms (i.e., atoms that do not directly interact) upon detection of photons emitted by each atom. Thus, interconnection attempts can be repeated for interconnection operations in a multi-QPU QC architecture.

[0051] In some aspects, the QPU network 400 may include a first vacuum chamber 402 having a first processor QPU 1 and a second processor QPU 2. The QPU network 400 may include a second vacuum chamber 404 having a third processor QPU 3 and a fourth vacuum chamber 406 having a fourth processor QPU 4. Other numbers of vacuum chambers and / or processors may also be implemented. The QPU network 400 may include an optical switch 410 configured to provide one or more paths for entangling qubits in processors QPU 1, QPU 2, QPU 3, QPU 4, as described below.

[0052] Figure 5An example of a viewport 500 according to some aspects of the present disclosure is shown. As shown, the viewport shows an exemplary ion chain, such as the ion chain 110 described above, such as Figure 5 Linear ion rows 510 in. It is advantageous that the optics used to collect photons for interconnect operations do not interfere with other functions of the QC. Aspects of the present disclosure include a light collection device (LCA) for an atomic quantum computing platform that enables efficient light collection for interconnect operations through the same viewport of a vacuum system, while also allowing readout of qubit states and addressing of individual qubits for gate operations. Readout, addressing, and interconnect operations are three functions of a multi-QPU atomic quantum computer that relies on high numerical aperture light access. Aspects of the present disclosure facilitate these operations while utilizing a single viewport toward the atoms. In addition, aspects of the present disclosure enable any-to-any interconnection between any QPUs in a quantum network using a switch that can operate on principles similar to the spacing components in the LCA.

[0053] Figure 6A-6C Example configurations of trapped ions in a QPU (e.g., QPU 1-4 as described above) according to some aspects of the present disclosure are shown. Atomic quantum computers consist of arrays of atoms trapped in a vacuum chamber. The size and dimensions of the atomic arrays may vary, but the spacing between atoms in a single cluster may be between 1 and 10 μm. At these spacings, the physical interactions between atoms are significant and can be used to create entanglement directly between a pair of atoms or between many atoms in the array. Figure 6C In the configuration shown, the ions can be shuffled, which allows for dynamic alignment.

[0054] Figure 7 Examples of states of trapped ions of a QPU according to aspects of the present disclosure are shown. In one aspect, the two energy levels of each atom in the QPU can be assigned as the "0" and "1" states of a qubit. Light of certain optical frequencies is used to drive single-qubit gates and multi-qubit gates. This light is typically focused more tightly than the typical distance between atoms, thereby enabling individual addressing of qubits. Ideally, the addressing light should be focused so that it has a uniform intensity distribution within the region where the atoms can move within the trap and does not crosstalk with neighboring atoms. These requirements can be achieved by an optical system with a high numerical aperture.

[0055] In certain aspects, readout of qubit states in an atomic (e.g., trapped ion) quantum computer is typically accomplished by driving one of the qubit states (e.g., state "1") on a strong transition and collecting and imaging the fluorescence on a detector. For high-fidelity readout of the computation, the optical system that collects the fluorescence photons for qubit readout may have high collection efficiency and good spatial resolution, so that the atomic images created at the detection plane do not have significant spatial overlap. An efficient imaging system with good spatial resolution may require optics with high numerical aperture access to the atoms.

[0056] In some aspects, achieving remote entanglement across QPUs in an atomic quantum computer may require collecting fluorescent photons from atoms in different QPUs that are not necessarily located in the same vacuum chamber (e.g. Figure 1 ). The frequencies of these photons may or may not match those of the photons collected for qubit readout. To achieve fast, high-fidelity interconnect operation, efficient collection of the photons into optical fibers or other photonic waveguides is required. When coupling fluorescence from multiple atoms into different fibers, high spatial resolution of the optical system may be required to minimize crosstalk between adjacent channels.

[0057] To flexibly interconnect different QPUs, the photons collected for the interconnect operation can be appropriately routed to create the appropriate links. The linked QPUs can be in the same vacuum chamber or in different chambers. In either case, the switch can determine which QPUs are optically connected to achieve long-range entanglement.

[0058] Figure 8 An example of an interconnect system 800 according to aspects of the present disclosure is shown. In some aspects, the interconnect system 800 may include one or more atomic arrays 802, which include a plurality of trapped ions in a vacuum chamber (not shown), as described above with respect to Figure 2 The chamber 250 described. One or more atomic arrays 802 may include one or more QPUs. The states of multiple trapped ions can be used to realize the quantum bit states of the QPU (not shown). The interconnection system 800 may include a vacuum chamber viewport 804 (e.g., viewport 500) configured to provide an optical path to the one or more atomic arrays 802 while maintaining the pressure in the vacuum chamber (not shown). The viewport 804 may include one or more glass plates. The interconnection system 800 may include an optical component 810 (e.g., a microscope objective). The optical component 810 may be a multi-lens optical device that is achromatic over the wavelength range spanned by the interconnection, readout, and addressing operations (e.g., from near infrared (IR) to near ultraviolet (UV)). The optical component 810 may be configured to correct for distortion introduced by the viewport 804.

[0059] In some aspects, the light for each primary function can be separated by two sequential components before being directed to each operation-specific unit. The interconnect unit and readout unit are intended to serve as output paths for collecting fluorescence, while the addressing unit provides optical access to individual qubits for light directed to the QPU.

[0060] In certain aspects, the interconnection system 800 may include a first switch 820 configured to separate an addressing beam, a readout beam, and an interconnection beam from an addressing unit 822. Specifically, the first switch 820 may be configured to direct the addressing beam from the addressing unit 822 to the optical component 810 and the one or more atomic arrays 802. The first switch 820 may be configured to direct the readout beam and the interconnection beam from the optical component 810 and the one or more atomic arrays 802 to the second switch 830.

[0061] In some aspects, the interconnect system 800 can include a second switch 830 configured to separate the readout beam and the interconnect beam. The second switch 830 can direct the interconnect beam to the interconnect unit 840 and direct the readout beam to the readout unit 850. The interconnect unit 840 can be coupled to one or more waveguide arrays associated with one or more QPUs. The readout unit 850 can be coupled to one or more photodetectors (e.g., the imaging system 230) configured to capture the readout beam.

[0062] In certain aspects, the interconnection beams can be directed to one or more QPUs, or to another switch, to achieve entanglement between multiple QPUs.

[0063] Fig. 9 A functional diagram of an interconnect system 800 according to aspects of the present disclosure is shown. In some aspects of the present disclosure, one or more atomic arrays 802 within a vacuum chamber are characterized by their full range S and the spacing d between qubits within the QPU. S includes the distance between QPUs in the same chamber, which determines the necessary field of view of the LAC, while d specifies the resolution required for the LAC.

[0064] In some aspects, optical component 810 can be characterized by its numerical aperture (NA), its field of view (FOV), its point spread function (PSF), and / or its effective focal length (f eff) to characterize the qubits. In order to image the qubits, the FOV must be at least as large as S. In order to address the qubits individually, the PSF of the objective lens within the entire FOV must indicate a resolution better than d (i.e., the distance between the first zeros of the Airy function image of a point source anywhere in the FOV should be less than d). NA sets the solid angle over which fluorescence can be collected from the atoms. NA is fundamentally limited by the viewport diameter D4 and the minimum working distance, which is the sum of D1, D2 and D3. Here, the optical component 810 can be a microscope objective that is considered to be in an infinite conjugate configuration.

[0065] In one aspect of the present disclosure, in an exemplary aspect, the first switch 820 may include a dichroic mirror. The addressing beam may be separated from the readout beam and the interconnection beam by the dichroic mirror. The wavelength λ of the light used to address the qubit add Fluorescence λ collected for readout and interconnect operation int,read This spacing of tens or hundreds of nanometers is sufficient for the thin-film interference of the dichroic mirror to isolate the addressing light efficiently.

[0066] In some aspects, the addressing unit 822 may include a variable magnification telescope having an average magnification M a Can be measured by δM a Adjustment is made so that the image of the atom can be mapped onto an array of laser beams generated by a diffractive optical device (not shown) and input to the addressing port of the LAC. According to an exemplary aspect, the magnification is determined by the requirement that each addressing beam has a significant overlap with only one atom. Since the typical motion of atoms is very small, this condition is mainly set by the spacing d. Although the input beam size and the spacing of the addressing beams can be measured offline, the spacing between atoms is usually unknown before the system is built. Therefore, adjustable magnification provides flexibility to optimize this mapping. In some aspects, a variable telescope design can provide the desired magnification and adjustment range, such as a variable telescope that only needs to translate the internal lens to change the magnification. In some embodiments, the outer dimensions of the addressing unit remain fixed when adjusting the magnification.

[0067] In certain aspects of the present disclosure, the second switch 830 can be configured to separate the readout beam and the interconnect beam using one or more schemes suitable for achieving entanglement. Examples of these schemes include frequency division multiplexing, space division multiplexing, and / or time division multiplexing. These solutions can be implemented individually or in combination in a given architecture. These schemes will be described in more detail below.

[0068] In some aspects of the present disclosure, the interconnection unit 840 may include one or more fiber-coupled lenses and / or waveguide arrays to collect fluorescence from trapped ions of one or more atomic arrays 802 for achieving long-range entanglement. An example implementation of a waveguide array includes a bundle of single-mode optical fibers and a rigid waveguide channel with micro-optics. The imaging magnification (M) of the fiber-coupled lens i ) is set so that the atomic image is aligned with the mode field diameter of the waveguide (P i ) between the waveguide channels. This in turn sets the spacing requirements between the waveguide channels for a given atomic configuration for interconnect operation (e.g. Fig.12 shown).

[0069] In some aspects, the readout unit 850 may include one or more variable magnification telescopes having an average magnification M r Can be measured by δM r Make adjustments.

[0070] In some aspects, the one or more photodetectors 860 can be configured to capture a readout beam associated with the state of the trapped ions in the one or more atomic arrays 802. The one or more photodetectors 860 can capture fluorescence in the readout beam associated with the trapped ions. The one or more photodetectors 860 can analyze the characteristics of the fluorescence to determine the state of the trapped ions. The one or more photodetectors 860 can include one or more devices (e.g., a charge coupled device, an avalanche photodiode, etc.) that are composed of an effective aperture (A r ), pixel size (P r ) and the number of pixels required (N r ) is used to characterize. r Determined by the desired size of the image on the photodetector, it can be set by the condition that the images of neighboring atoms have negligible overlap while minimizing the number of used pixels (e.g. Fig.11 ). The object size of the atoms in the trap may be small compared to the resolution of the microscope objective, so the PSF of the microscope objective can be used to specify this magnification. As mentioned earlier, the adjustable magnification allows the image size to be optimized for different distances d between qubits.

[0071] In some aspects of the present disclosure, a single switch may be used to modulate the addressing beam, the readout beam, and the interconnect beam. The single switch may modulate the beam using a combination of frequency division multiplexing, time division multiplexing, and / or space division multiplexing.

[0072] Figure 10A-10C An example scheme for multiplexing beams according to aspects of the present disclosure is shown. Fig. 9 and 10A - Fig. 10C, the second switch 830 can be configured to implement one or more of frequency division multiplexing, space division multiplexing and / or time division multiplexing. Fig. 10A An example of frequency division multiplexing is shown. The readout beam and the interconnection beam can impinge on the first mirror 1002 as a combined beam. read ) and interconnecting beams (λ int ), the first reflector 1002 can direct the readout beam in a first direction (e.g., toward the readout unit 850) and direct the interconnection beam in a second direction (e.g., toward the interconnection unit 840).

[0073] Fig. 10B An example of space division multiplexing according to various aspects of the present disclosure is shown. The readout beam and the interconnection beam can be guided by the first lens 1004, the second reflector 1006 and / or the optional second lens 1008 to achieve space division multiplexing. The first lens 1004 can refract the readout beam and the interconnection beam toward different spatial locations. For example, the first lens 1004 can refract the interconnection beam toward the second reflector 1006 and refract the readout beam toward the optional second lens 1008. The second reflector 1006 can reflect the interconnection beam toward a second direction (e.g., toward the interconnection unit 840). The optional second lens 1008 can refract the readout beam toward a first direction (e.g., toward the readout unit 850). In an alternative embodiment, the first lens 1004 can refract the interconnection beam and the readout beam toward the second reflector 1006. The second reflector 1006 can reflect the readout beam toward the first direction and reflect the interconnection beam toward the second direction. Other configurations can also be implemented.

[0074] Fig. 10C An example of time division multiplexing according to aspects of the present disclosure is shown. The readout beam and the interconnection beam can be directed by the third reflector 1008 at different times to achieve time division multiplexing. For example, the interconnection beam can hit the third reflector 1008 at a first time. The third reflector 1008 (at the first time) can reflect the interconnection beam toward a second direction. The readout beam can hit the third reflector 1008 at a second time different from the first time. Before the second time, the third reflector 1008 can be moved and / or rotated in space so that when the readout beam hits the third reflector 1008, the third reflector 1008 can reflect the readout beam toward the first direction. Other configurations can also be implemented.

[0075] Fig.13 FIG. 8 is a diagram showing an example of operation of a second switch 830 routing interconnect beams according to aspects of the present disclosure. Figure 8-Figure 10, the second switch 830 enables the fluorescent photons collected by the interconnection unit 840 of the interconnection system 800 to be routed to a unit (not shown) that realizes remote entanglement between QPUs. These QPUs can be located in the same vacuum chamber or in different chambers. The second switch 830 can be composed of a tip-tilt mirror similar to that described, for separating light for readout and interconnection operations. Alternatively or additionally, the second switch 830 can be a photonic quantum computer that uses a Mach-Zehnder interferometer etched into a silicon waveguide to route photons along different paths. After routing, the photons are sent to a unit that realizes remote entanglement by interfering the photon pairs on a 50 / 50 beam splitter, thereby erasing the path information. Figure 14A-14B An example implementation of these units is shown in for photons with entanglement encoded in, but not limited to, polarization and occupied degrees of freedom.

[0076] refer to Figure 14A-14B , which shows an example cell that foreshadows long-range entanglement. A beam splitter causes the fluorescent photons to interfere, erasing the path information. The photons are then detected in a Bell state analyzer setup (a) or coincidence detection (b), depending on the degree of freedom that the photons use for entanglement.

[0077] Fig.15 A method 1500 for implementing remote entanglement according to aspects of the present disclosure is shown. The method 1500 may be performed by one or more of the QIP system 200, the computer device 300, and / or the interconnect system 800, and / or one or more subcomponents thereof.

[0078] At 1505 , method 1500 can receive a readout beam associated with a state of a first qubit of the trapped ion array. For example, optics 810 , first switch 820 , second switch 830 , and / or interconnect system 800 can receive a readout beam from one or more atomic arrays 802 .

[0079] At 1510, method 1500 can receive an interconnect beam configured to entangle a second qubit of the array with an external qubit of an external array. For example, optical component 810, first switch 820, second switch 830, and / or interconnect system 800 can receive an interconnect beam configured to entangle qubits of one or more atomic arrays 802 with qubits in another QPU.

[0080] At 1515 , method 1500 can receive an addressing beam from an addressing unit configured to control a state of a third qubit of the array. For example, first switch 820 , second switch 830 , and / or interconnect system 800 can receive an addressing beam from addressing unit 822 .

[0081] At 1520, method 1500 can direct the addressing beam from the addressing unit to the third qubit via at least one switch. For example, general controller 205, optical and trap controller 220, QIP system 200, processor 310, memory 320, user interface 350, operating system 360, computer device 300, switch 820, second switch 830, and / or interconnect system 800 can direct the addressing beam to one or more atomic arrays 802.

[0082] At 1525, method 1500 can direct the readout beam to the photodetector via at least one switch. For example, general controller 205, optical and trap controller 220, QIP system 200, processor 310, memory 320, user interface 350, operating system 360, computer device 300, switch 820, second switch 830, and / or interconnect system 800 can direct the readout beam to readout unit 850 and / or one or more photodetectors 860.

[0083] At 1530, method 1500 can direct the interconnection beam to an interconnection unit optically coupled to an external array via at least one switch. For example, general controller 205, optical and trap controller 220, QIP system 200, processor 310, memory 320, user interface 350, operating system 360, computer device 300, switch 820, second switch 830, and / or interconnection system 800 can direct the interconnection beam to interconnection unit 840.

[0084] Aspects of the present disclosure include a method for receiving a readout beam associated with a state of a first qubit of a trapped ion array, receiving an interconnection beam configured to entangle a second qubit of the array with an external qubit of an external array, receiving an addressing beam configured to control a state of a third qubit of the array from an addressing unit, directing the addressing beam from the addressing unit to the third qubit through at least one switch, directing the readout beam to a photodetector through at least one switch, and directing the interconnection beam to an interconnection unit optically coupled to the external array through at least one switch.

[0085] Aspects of the present disclosure include the above method, further comprising receiving the readout beam and the interconnection beam via a viewport.

[0086] Aspects of the present disclosure include any of the above methods, further comprising multiplexing the addressing beam and the combination of the readout beam and the interconnection beam by frequency division multiplexing.

[0087] Aspects of the present disclosure include any of the above methods, further comprising multiplexing the readout beam and the interconnection beam by frequency division multiplexing.

[0088] Aspects of the present disclosure include any of the above methods, further comprising multiplexing the readout beam and the interconnection beam by time division multiplexing.

[0089] Aspects of the present disclosure include any of the above methods, further comprising multiplexing the readout beam and the interconnection beam by space division multiplexing.

[0090] The above description of the present disclosure is provided to enable those skilled in the art to make or use the present disclosure. Various modifications to the present disclosure will be apparent to those skilled in the art, and the common principles defined herein may be applied to other variations without departing from the scope of the present disclosure. In addition, although the elements of the described aspects may be described or claimed in the singular, the plural form may be considered unless explicitly stated to be limited to the singular. In addition, unless otherwise stated, all or a portion of any aspect may be used together with all or a portion of any other aspect. Therefore, the present disclosure is not limited to the examples and designs described herein, but should conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for remotely entangled quantum processing units (QPUs), comprising: receiving a readout beam associated with a state of a first qubit of the array of trapped ions; receiving an interconnection light beam configured to entangle a second qubit of the array with an external qubit of an external array; receiving, from an addressing unit, an addressing beam configured to control a state of a third qubit of the array; directing the addressing beam from the addressing unit to the third qubit via at least one switch; directing the readout beam to a photodetector via the at least one switch; and The interconnection light beam is directed via the at least one switch to an interconnection unit optically coupled to the external array.

2. The method of claim 1, further comprising receiving the readout beam and the interconnection beam via a viewport.

3. The method of claim 1, further comprising multiplexing the addressing beam with a combination of the readout beam and the interconnection beam via frequency division multiplexing.

4. The method of claim 1, further comprising multiplexing the readout beam and the interconnection beam via frequency division multiplexing.

5. The method of claim 1, further comprising multiplexing the readout beam and the interconnection beam via time division multiplexing.

6. The method of claim 1, further comprising multiplexing the readout beam and the interconnection beam via space division multiplexing.

7. An interconnect system for a remotely entangled quantum processing unit (QPU), comprising: arrays of trapped ions; an addressing unit configured to send an addressing light beam; At least one switch, configured as: receiving a readout beam associated with a state of a first qubit of the array of trapped ions; receiving an interconnection light beam configured to entangle a second qubit of the array with an external qubit of an external array; receiving from the addressing unit the addressing beam configured to control a state of a third qubit of the array; directing the addressing beam from the addressing unit toward the third qubit; directing the readout beam to a photodetector; and directing the interconnection light beam to an interconnection unit; The interconnect unit is configured to optically couple with the external array; and The photodetector is configured to capture light emitted from the readout beam.

8. The interconnect system of claim 7, further comprising a vacuum chamber, wherein the array of trapped ions is disposed within the vacuum chamber.

9. The interconnect system of claim 8, further comprising a viewport disposed between the array of trapped ions and the at least one switch.

10. The interconnect system of claim 9, further comprising an optical component disposed between the viewport and the at least one switch.

11. The interconnect system of claim 10, wherein the optical component comprises a microscope objective.

12. The interconnect system of claim 7, wherein the addressing unit comprises a variable magnification telescope.

13. The interconnection system of claim 7, further comprising a readout unit disposed between the at least one switch and the photodetector.

14. The interconnect system of claim 13, wherein the readout unit comprises a variable magnification telescope.

15. The interconnect system of claim 7, wherein the photodetector comprises a charge coupled device or an avalanche photodiode.

16. The interconnection system of claim 7, wherein the at least one switch comprises a first switch configured to multiplex the addressing beam with a combination of the readout beam and the interconnection beam via a first mirror.

17. The interconnection system of claim 16, wherein: The at least one switch includes a second switch configured to receive a combination of the readout beam and the interconnection beam; and The second switch includes a second mirror configured to multiplex the readout beam and the interconnection beam.

18. The interconnection system of claim 16, wherein: The at least one switch includes a second switch configured to receive a combination of the readout beam and the interconnection beam; and The second switch includes a movable mirror and a lens, and the second switch is configured to multiplex the readout beam and the interconnection beam via the movable mirror and the lens.

19. The interconnection system of claim 16, wherein: The at least one switch includes a second switch configured to receive a combination of the readout beam and the interconnection beam; and The second switch includes a rotatable mirror and a lens, and the second switch is configured to multiplex the readout beam and the interconnection beam via the rotatable mirror and the lens.

20. The interconnection system of claim 7, wherein the interconnection unit comprises one or more of a waveguide, a fiber-coupled lens, or an optical fiber.

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