Dual individually addressable multibeam Raman system

Abstract

Aspects of the present disclosure generally relate to systems and methods for use in implementing and / or operating a quantum information processing (QIP) system, and more particularly, to a dual individually addressable multi-beam Raman system for use in a QIP system. Techniques are described in which a first multi-channel modulator (MCM), a first telecentric zoom lens, and a first interleaver form a first optical path of the Raman system, the first optical path receiving an array of first beams and conditioning the array of first beams to individually address atom-based quantum bits in the chain from a first direction. Also, a second MCM, a second telecentric zoom lens, and a second interleaver form a second optical path of the Raman system, the second optical path receiving an array of second beams and conditioning the array of second beams to individually address atom-based quantum bits in the chain from a second direction.

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63 / 287,002, entitled "DOUBLE INDIVIDUAL-ADDRESSING MULTI-BEAM RAMAN SYSTEM," filed December 7, 2021, and U.S. Provisional Patent Application No. 18 / 062,413, entitled "DOUBLE INDIVIDUAL ADDRESSING MULTI-BEAM RAMAN SYSTEM," filed December 6, 2022, the entire contents of which are incorporated herein by reference.

[0002] Aspects of the present disclosure relate generally to systems and methods for use in implementing and / or operating quantum information processing (QIP) systems, and more particularly to a double individual-addressing multi-beam Raman system for use in a QIP system. [Background technology]

[0003] Trapped atoms are one of the main implementations of quantum information processing or quantum computing. Atom-based qubits can be used as quantum memories, as quantum gates in quantum computers and quantum simulators, and can function as nodes in quantum communication networks. Qubits based on trapped atomic ions enjoy a rare combination of attributes. For example, qubits based on trapped atomic ions have very good coherence properties, can be prepared and measured with nearly 100% efficiency, and are easily entangled by modulating the Coulomb interaction with a suitable external control field, such as an optical or microwave field. These attributes make atom-based qubits attractive for extended quantum operations, such as quantum computation or quantum simulation. Summary of the Invention [Problem to be solved by the invention]

[0004] It is therefore important to develop new techniques to improve the design, fabrication, implementation, and / or control of various QIP systems used as quantum computers or quantum simulators, particularly QIP systems that involve operations based on atom-based qubits. [Means for solving the problem]

[0005] The following presents a simplified summary of one or more aspects to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is not intended to identify key or critical elements of all aspects or to delineate 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 the more detailed description that is presented later.

[0006] This disclosure describes various aspects of a dual individually addressable multi-beam Raman system for use in a QIP system.

[0007] Aspects of the present disclosure describe a Raman system for dual individual addressing of atom-based quantum bits, the Raman system including a first multi-channel modulator (MCM), a first telecentric zoom lens, and a first interleaver, which together with one or more optical components form a first optical path of the Raman system and are configured to receive a first array of beams and adjust the first array of beams such that each beam in the first array of beams individually addresses each atom-based quantum bit in the chain from a first direction. The Raman system further includes a second MCM, a second telecentric zoom lens, and a second interleaver, which together with one or more optical components form a second optical path of the Raman system and are configured to receive a second array of beams and adjust the second array of beams such that each beam in the second array of beams individually addresses each atom-based quantum bit in the chain from a second direction different from the first direction. The first optical path and the second optical path can be symmetric.

[0008] In one aspect of this Raman system, each beam in the first array of beams is an elliptical beam, each beam in the second array of beams is an elliptical beam, and corresponding elliptical beams from the first array of beams and the second array of beams substantially overlap. The elliptical beams may be Gaussian beams.

[0009] In one aspect of this Raman system, the Raman system can further include a laser source, a first diffractive optical element (DOE), and a second DOE, where the laser source is configured to generate a single beam, the single beam being split and a portion provided to the first DOE, the first DOE configured to generate an array of first beams from the portion of the single beam, and the remaining portion of the single beam being provided to the second DOE, the second DOE configured to generate an array of second beams from the remaining portion of the single beam.

[0010] In one embodiment of this Raman system, the first MCM is a first multichannel acousto-optic modulator (AOM) and the second MCM is a second multichannel AOM, where the channels in the first multichannel AOM include one channel for each beam in the array of first beams, each channel in the first multichannel AOM configured to independently control one or more properties of each beam in the array of first beams applied to the channel, and the channels in the second multichannel AOM include one channel for each beam in the set of second beams, each channel in the second multichannel AOM configured to independently control one or more properties of each beam in the array of first beams applied to the channel. Additionally or alternatively, the first array of beams received by the first optical path has a beam spacing that matches the spacing between channels in the first multi-channel AOM, and the second array of beams received by the second optical path has a beam spacing that matches the spacing between channels in the second multi-channel AOM, the first optical path is configured to adjust the beam spacing of the first array of beams to match the spacing of the atom-based quantum bits in the chain, and the second optical path is configured to adjust the beam spacing of the second array of beams to match the spacing of the atom-based quantum bits in the chain. The first optical path is further configured to adjust the beam size of the beams in the first array of beams according to an optimal size (e.g., based on tunability and complexity metrics) of the atom-based quantum bits in the chain, and the second optical path is further configured to adjust the beam size of the beams in the second array of beams according to the size of the atom-based quantum bits in the chain.

[0011] In one aspect of this Raman system, the first telecentric zoom lens and the second telecentric zoom lens each have an outer lens pair and an inner lens pair, where the outer lens pair is fixed in position and the inner lens pair is configured to move together to adjust the optical properties, or the inner lens pair is fixed in position and the outer lens pair is configured to move together to adjust the optical properties.

[0012] In one aspect of this Raman system, the first array of beams includes a subset of the first beams and a subset of the second beams, the first interleaver is configured to optically adjust positions of beams in the first array of beams such that beams from the first subset of beams and beams from the second subset of beams are interleaved and have reduced beam spacing at an output of the first interleaver, and the second array of beams includes a subset of the first beams and a subset of the second beams, the second interleaver is configured to optically adjust positions of beams in the second array of beams such that beams from the first subset of beams and beams from the second subset of beams are interleaved and have reduced beam spacing at an output of the second interleaver. The first interleaver includes a first path for a subset of a first beam from the first array of beams and a second path for a subset of a second beam from the first array of beams, and the second interleaver includes a first path for the subset of a first beam from the second array of beams and a second path for the subset of a second beam from the second array of beams.

[0013] In one embodiment of this Raman system, the first optical path is further formed by a first reflective Dove prism and the second optical path is further formed by a second reflective Dove prism.

[0014] In one aspect of this Raman system, a first direction for each beam in the array of first beams to individually address each atom-based quantum bit in the chain is opposite to a second direction for each beam in the array of second beams to individually address each atom-based quantum bit in the chain.

[0015] In one aspect of this Raman system, each of the atom-based qubits in the chain is an ion.

[0016] Aspects of the present disclosure describe a method for dual individual addressing of atom-based quantum bits in a Raman system, the method including providing a first multi-channel modulator (MCM), a first telecentric zoom lens, and a first interleaver forming a first optical path with one or more optical components. The method also includes providing a second MCM, a second telecentric zoom lens, and a second interleaver forming a second optical path with one or more optical components. The method includes receiving an array of first beams via the first optical path and adjusting the array of first beams such that each beam in the first array of beams individually addresses each atom-based quantum bit in the chain from a first direction via the first optical path, and receiving an array of second beams via the second optical path and adjusting the array of second beams such that each beam in the second array of beams individually addresses each atom-based quantum bit in the chain from a second direction via the second optical path.

[0017] In one aspect of the method, each beam in the first array of beams is an elliptical beam and each beam in the second array of beams is an elliptical beam, and corresponding elliptical beams from the first array of beams and the second array of beams substantially overlap.

[0018] In one aspect of this method, the method further includes independently controlling, at each channel of the first multi-channel MCM, one or more characteristics of each beam of an array of first beams applied to that channel, and independently controlling, at each channel of the second multi-channel MCM, one or more characteristics of each beam of an array of second beams applied to that channel.

[0019] In one aspect of this method, the method further includes adjusting, by a first optical path, a beam spacing of the array of first beams to match the spacing of the atomic-based quantum bits in the chain, and adjusting, by a second optical path, a beam spacing of the array of second beams to match the spacing of the atomic-based quantum bits in the chain.

[0020] In one aspect of the method, the first array of beams includes a subset of the first beams and a subset of the second beams, and the second array of beams includes the subset of the first beams and the subset of the second beams, and the method further includes the steps of adjusting positions of beams in the first array of beams such that beams from the first subset of beams and beams from the second subset of beams are alternated by a first interleaver and have reduced beam spacing at an output of the first interleaver, and adjusting positions of beams in the second array of beams such that beams from the first subset of beams and beams from the second subset of beams are alternated by a second interleaver and have reduced beam spacing at an output of the second interleaver.

[0021] Individual aspects of the Raman systems described above can be combined to provide other contemplated implementations of the Raman system.Similarly, individual aspects of the methods described above can be combined to provide other contemplated implementations of the methods.

[0022] To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of only a few of the various ways in which the principles of the various aspects may be employed, and the description is intended to include all such aspects and their equivalents.

[0023] The disclosed aspects are described below in conjunction with the accompanying drawings, which are provided to illustrate but not to limit the disclosed aspects, and in which like reference numerals represent like elements. [Brief description of the drawings]

[0024] [Figure 1] FIG. 2 is a diagram of atomic ions in a linear crystal or chain according to an aspect of the present disclosure. [Diagram 2] FIG. 1 illustrates an example of a quantum information processing (QIP) system according to an aspect of the present disclosure. [Diagram 3] FIG. 2 illustrates an example of a computing device according to an aspect of the present disclosure. [Figure 4] FIG. 1 illustrates an example of a conventional Raman beam geometry in accordance with aspects of the present disclosure. [Diagram 5] FIG. 1 illustrates an example of a dual discrete geometry according to aspects of the present disclosure. [Figure 6] FIG. 13 illustrates an example of crosstalk differences according to aspects of the present disclosure. [Figure 7] FIG. 13 illustrates an example of power efficiency differences according to aspects of the present disclosure. [Figure 8] FIG. 13 illustrates an example of the difference between spontaneous emission and idle error in accordance with aspects of the present disclosure. [Figure 9] FIG. 1 illustrates an example schematic diagram of a Raman system providing a dual individual addressing scheme in accordance with aspects of the present disclosure. [Figure 10A] FIG. 1 illustrates an example of a reflective Dove prism according to aspects of the present disclosure. [Figure 10B]FIG. 1 illustrates an example of a reflective Dove prism according to aspects of the present disclosure. [Figure 11] FIG. 2 is an exemplary schematic diagram of a simplified telecentric zoom lens for a dual discrete system according to aspects of the present disclosure. [Figure 12] FIG. 1 illustrates a simplified telecentric zoom lens mechanical implementation according to an aspect of the present disclosure. [Figure 13A] FIG. 2 illustrates an example of a schematic diagram of an interleaver function according to an aspect of the present disclosure. [Figure 13B] FIG. 2 illustrates an example of a schematic diagram of an interleaver function according to an aspect of the present disclosure. [Figure 14] FIG. 1 illustrates an example of beam and ion numbering after an interleaver according to an aspect of the present disclosure. [Figure 15] 1 is a flowchart of a method for dual individual addressing of atom-based qubits in a Raman system according to an aspect of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] The detailed description set forth below in conjunction with the accompanying drawings or figures is intended as a description of various configurations or implementations and is not intended to represent the only configurations or implementations in which the concepts described herein may be practiced. The detailed description includes specific details to provide a thorough understanding of the various concepts. However, it will be apparent to one of ordinary skill in the art that these concepts may be practiced without these specific details or with variations of these specific details. In some instances, well-known components are shown in block diagram form, and some blocks may represent one or more well-known components.

[0026] Previous designs of trapped ion quantum computers capable of individually addressing large linear arrays of qubits (see, for example, Figure 1 below) with a Raman laser beam have used optical elements such as diffractive optical elements (DOEs) to create a linear array of individually addressed beams, which are then fed into a multi-channel modulator (MCM) such as an acousto-optic modulator (AOM) to manipulate the individually addressed beams individually. This was then used in combination with a large "global" addressing laser beam that simultaneously addresses all the qubits to fulfill the overall requirement of individual addressability in a trapped ion quantum computer. The combination of DOEs and MCMs to generate the individually addressed beams is one example for individual addressability, and can be done in other ways as well. One such example is the use of fiber-coupled individual modulators (one per beam), where the output of the fiber array is used to generate the individually addressed beam array.

[0027] Quantum gates can be targeted to specific qubits or pairs of qubits in a linear array or chain of qubits (e.g., ions) by turning on one or two AOM channels on a multichannel AOM. Quantum gates requiring more than two qubits can be realized by turning on more AOM channels on a multichannel AOM. These individually addressed laser beams, when combined with a much larger global beam, produce the desired gate operation. This laser beam geometry has the advantage of simplicity, since the optics required to generate a large array of tightly focused individually addressed laser beams are complex, but it is easy to generate a single "global" beam with a broad spatial profile that hits all the ions in the ion trap. The individually addressed laser beams and the global beam can be provided from different directions (e.g., opposing directions).

[0028] However, there may be some challenges with this laser beam geometry. For example, a large global beam may induce idle phase errors throughout the qubit register, even on qubits that are not involved in a particular gate, as they are illuminated. The global beam may also increase gate crosstalk errors, which may be difficult to mitigate in all circumstances. Finally, the global beam may also increase fundamental errors due to spontaneous emission. This may occur in two ways: first, if the laser intensity for a given ion is not matched between the two beams, the spontaneous emission error per gate may increase. In practical terms, this may occur due to the spatial profile of the global beam being non-uniform, such as a Gaussian spatial profile of finite width. Second, since the global beam illuminates qubits other than the target, they are illuminated even when idle, so the spontaneous emission error per qubit increases, and the increase in spontaneous emission error per qubit increases the overall error by the number of qubits in the register, so the amount of spontaneous emission is multiplied by the size of the qubit register.

[0029] Because of these potential challenges, it would be desirable to instead have an optical system capable of individually addressing a single qubit from both sides, i.e., a dual set of individually addressable Raman beams. However, this type of beam geometry has some unique challenges. Both sides need to produce beams with very well matched spacing, telecentricity, polarization, and spatial profile in the ion plane, the beam array axis needs to be aligned with the multichannel AOM axis, and the multichannel AOM axis needs to be aligned with the ion chain axis. Motorized degrees of freedom may also be needed to adjust the alignment in response to slow system drift.

[0030] Since the fidelity of laser-based gating depends on the stability of the laser intensity and phase sampled at the ion position, tightly focused beams can experience increased intensity noise due to beam pointing fluctuations. This noise can be reduced by reducing mechanical vibrations in the optical assembly or by increasing the size of the beam to reduce sensitivity to a given amount of pointing noise. Unfortunately, the design constraints of multichannel AOM devices make it difficult to design devices that can tolerate arbitrary beam waists and spacings. The limitations implied by bulk optics mean that the ratio of beam waist to spacing in AOM devices must be preserved at the ion plane, and while having more closely spaced ion chains is desirable for many reasons unrelated to Raman optomechanics (e.g., reduced ion heating, reduced sensitivity to stray magnetic field drift in ion traps), it would also require a reduced beam waist and thus increased sensitivity to alignment drift and pointing noise.

[0031] This disclosure describes a technique to mitigate the constraints outlined above based on the use of optical interleavers, which will be discussed in more detail below. This disclosure also proposes using cylindrical optics to increase the beam waist in the direction transverse to the ion chain axis. This has several practical implications. First, gate errors due to pointing noise along that axis are reduced. Second, one-qubit and two-qubit quantum gates often require multiple tones to be applied simultaneously to the AOM to generate multiple laser frequency components on the ion. Each frequency component has its own pointing offset from the AOM, which is ideally reimaged to the same point in the ion plane (called the geometric focus). In practice, it is difficult to match the geometric focus to the same location as a Gaussian focus where each laser beam has maximum intensity and an ideal optical phase profile. Pointing shifts occur along the transverse direction, and stretching using cylindrical optics in this direction can reduce sensitivity to this particular alignment offset. Having at least one axis with a larger beam waist can be used to reduce certain undesirable polarization artifacts that appear when the beam waist approaches the wavelength of light. Finally, by matching the transverse numerical aperture (NA) of the individually addressed beams to the reduced numerical aperture available in the transverse direction due to the geometric constraints of the ion trap packaging, it is possible to optimize scattered light, clipping, etc.

[0032] This disclosure also describes a system for generating a matched set of individually addressed laser beams that reduces crosstalk, utilizes laser power more efficiently, reduces phase errors in idle qubits, reduces the effects of spontaneous emission (fundamental limits), addresses new degrees of freedom (e.g., use of K-mirrors or Dove prisms for alignment of the fan to the ions, zoom lenses), and addresses optical invariants (e.g., fixed waist / spacing ratio) using interleavers.

[0033] Solutions to problems that may arise when implementing techniques for dual individual addressing in multi-beam Raman systems are described in more detail in relation to Figures 1-15, which provide background on the types of QIP systems or quantum computers, more particularly atom-based QIP systems or quantum computers, in which these techniques are implemented.

[0034] FIG. 1 shows a diagram 100 illustrating an example of a plurality of atomic ions 106 (e.g., atomic ions 106a, 106b, ..., 106c, and 106d) trapped in a linear crystal or chain 110 using a trap (which may be in a vacuum chamber as shown in FIG. 2). The trap may be referred to as an ion trap. The illustrated ion trap 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 in the chain 110.

[0035] In the example shown in FIG. 1, the trap includes electrodes for trapping or confining a number of atomic ions in chains 110 that are laser-cooled to be nearly stationary. The number of trapped atomic ions (N) can be configurable, allowing more or fewer atomic ions to be trapped. The atomic ions can be, for example, ytterbium ions ( 171 Yb + ions, etc. Atomic ions are 171 Yb +The atomic ions are illuminated with laser (light) radiation tuned to the resonance of the ytterbium atom, and the fluorescence of the atomic ions is imaged onto a camera or other type of detection device. In this example, the atomic ions may be spaced apart from each other by about 5 microns (μm), but the separation may be less than 5 μm or more than 5 μm. The separation of the atomic ions is determined by a balance between external confinement forces and Coulomb repulsion, and need not be uniform. Furthermore, in addition to ytterbium atomic ions, neutral atoms, Rydberg atoms, different atomic ions, or different species of atomic ions may also be used. For example, barium ions containing different isotopes of barium may be used. The trap may be a linear RF power trap, but other types of confinement devices may also be used, including optical confinement. Thus, the confinement device may be based on a variety of technologies, for example, to hold ions, neutral atoms, or Rydberg atoms, with an ion trap being one example of such a confinement device. The ion trap may be, for example, a surface trap.

[0036] The ions 106 (or other forms of atom-based qubits) in the chain 110 can be individually addressed from different directions by using techniques described below.

[0037] 2 illustrates an example block diagram of a QIP system 200. The QIP system 200 may also be referred to as a quantum computing system, a quantum computer, a computing device, an ion trap type 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 to perform classical computations and operations. In such a hybrid system, quantum and classical computations and operations may interact.

[0038] 2 shows a general purpose controller 205 configured to perform various control operations of the QIP system 200. Instructions for the control operations can be stored in a memory (not shown) in the general purpose controller 205 and can be updated over time via a communication interface (not shown). Although the general purpose controller 205 is shown separate from the QIP system 200, the general purpose controller 205 can be integrated with or part of the QIP system 200. The general purpose controller 205 can include an automation and calibration controller 280 configured to perform various calibration, testing, and automation operations associated with the QIP system 200. These calibration, testing, and automation operations can involve, for example, all or a portion of the optics and trap controller 220 and / or all or a portion of the chamber 250.

[0039] QIP system 200 can include an algorithm component 210 that can operate with other parts of QIP system 200 to perform quantum algorithms or operations, including stacks or sequences of one-qubit and / or multi-qubit (e.g., two-qubit) operations, as well as combinatorial stacks or sequences of extended quantum computations. Thus, algorithm component 210 can provide instructions to various components of QIP system 200 (e.g., optical and trap controller 220) to enable the implementation of quantum algorithms or operations. Algorithm component 210 can receive information resulting from implementing a quantum algorithm or operation and can process the information and / or forward the information to other components of QIP system 200 or other devices for further processing.

[0040] The QIP system 200 can include an optics and trap controller 220, which controls various aspects of the trap 270 in the chamber 250, including generating signals to control the trap 270, and controls the operation of a laser and optics that provide a light beam that interacts with atoms or ions in the trap 270. Controlling the operation of the laser and optics can include dynamically changing operating parameters and / or settings, including controlling positioning using a motorized mount or holder. The trap 270 can be referred to as an ion trap when used to confine or trap ions. However, the trap 270 can also be used to trap neutral atoms, Rydberg atoms, different atomic ions, or different species of atomic ions. The laser and optics can be at least partially located in the optics and trap controller 220 and / or in the chamber 250. For example, the optics and trap controller 220 and the optics in the chamber 250 can refer to optical components or optical assemblies.

[0041] The QIP system 200 can include an imaging system 230. The imaging system 230 can 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 being provided to the trap 270 and / or after they have been provided to the trap 270. In one aspect, the imaging system 230 can be implemented separately from the optics and trap controller 220, although detection, identification, and labeling of the atomic ions using fluorescence and with image processing algorithms may need to be coordinated with the optics and trap controller 220.

[0042] In addition to the above-mentioned components, QIP system 200 can 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. Where atomic ions are the basis of quantum operations, trap 270 confines the ionized (e.g., photoionized) atomic species. Trap 270 can be part of the processor or processing portion of QIP system 200. That is, trap 270 can be considered to be the core of the processing operations of QIP system 200, as it holds the atomic-based qubits that are used to perform quantum operations or simulations. At least a portion of source 260 can be implemented separately from chamber 250.

[0043] It should be understood that the various components of the QIP system 200 shown in Figure 2 are depicted at a high level for ease of understanding. Such components may include one or more subcomponents, details of which may be provided below as necessary to better understand certain aspects of the present disclosure.

[0044] Aspects of the present disclosure may be implemented at least in part using the optics and trapping controller 220 , the imaging system 230 , and / or the chamber 250 of the QIP system 200 .

[0045] Referring now to FIG. 3, an example of a computer system or device 300 is shown. The computer device 300 may represent, for example, a single computing device, multiple computing devices, or a distributed computing system. The computer device 300 may 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, the computer device 300 may 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., a quantum algorithm) are shared with other sets of operations (e.g., classical computer data processing). A typical example of a computer device 300 implemented as a QIP system capable of performing quantum computations and simulations is, for example, the QIP system 200 shown in FIG. 2.

[0046] The computing device 300 may include a processor 310 for performing processing functions related to one or more of the functions described herein. The processor 310 may include one or more sets of processors or multi-core processors. Furthermore, the processor 310 may be implemented as an integrated and / or 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 intelligence 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 computing device 300, and the computing device 300 may also include additional processors 310 for performing further specific functions (e.g., including functions for controlling the operation of the computing device 300).

[0047] The computing 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 to be processed by the processor 310 and / or data resulting from processing by the processor 310. In one implementation, for example, the memory 320 may correspond to a computer-readable storage medium that stores code or instructions for performing one or more functions or operations. As with the processor 310, the memory 320 may refer to a general-purpose memory of the computing device 300, and the computing device 300 may also include additional memory 320 for storing instructions and / or data for further specific functions.

[0048] It will be appreciated that the processor 310 and memory 320 may be used in connection with a variety of operations, including, but not limited to, computing, calculation, simulation, control, calibration, system management, and other operations of the computing device 300, including the methods or processes described herein.

[0049] Additionally, the computing device 300 may include a communications component 330 that utilizes hardware, software, and services to enable the computing device 300 to establish and maintain communications with one or more entities. The communications component 330 may also be used to communicate between components of the computing device 300 and between the computing device 300 and external devices, such as devices located across a communications network and / or devices serially or locally connected to the computing device 300. For example, the communications component 330 may include one or more buses and may further include transmit and receive chain components associated with transmitters and receivers, respectively, operable to interface with external devices. The communications component 330 may be used to receive updates regarding the operation or functionality of the computing device 300.

[0050] Additionally, computing device 300 can include data store 340, which can be any suitable combination of hardware and / or software that provides mass storage of information, databases, and programs used in connection with the operation of computing device 300 and / or any method or process described herein. For example, data store 340 can be a data repository for operating system 360 (e.g., a classical OS, a quantum OS, or both). In one implementation, data store 340 can include memory 320. In one implementation, processor 310 can execute, and memory 320 or data store 340 can store, operating system 360 and / or applications or programs.

[0051] The computing device 300 may also include a user interface component 350 configured to receive input from a user of the computing device 300 and further configured to generate output for presentation to the user or for provision (directly or indirectly) to a different system. 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, navigation keys, function keys, a microphone, a voice recognition component, any other mechanism capable of receiving input from a user, or any combination thereof. Additionally, the user interface component 350 may include one or more output devices, including but not limited to a display, a speaker, a haptic feedback mechanism, a printer, any other mechanism capable of presenting output to a user, or any combination thereof. In one implementation, the user interface component 350 may send and / or receive messages corresponding to operations of the operating system 360. When the computing device 300 is implemented as part of a cloud-based infrastructure solution, the user interface component 350 may be used to enable a user of the cloud-based infrastructure solution to remotely interact with the computing device 300.

[0052] Techniques for generating dual sets of individually addressing laser beams to atom-based qubits in a quantum computer are described in more detail below in conjunction with the systems described in FIGS. 1-3.

[0053] FIG. 4 shows a diagram 400 illustrating an example of a conventional Raman beam geometry, which may be called an individual-global geometry. A global beam 420 is incident on an ion chain having a number of ions 406. The global beam 420 is incident from one direction, here from above towards the ions 406. The global beam 420 is shaped to address the entire ion chain (hence the term "global"). That is, the global beam 420 is wide enough to be incident on each of the ions 406 (i.e., qubits) in the ion chain. To achieve individual addressing, which is a requirement for universal computation, a set of individual beams 410 that individually address the ions 406 in the ion chain is incident from a direction different from that of the global beam 420. In this case, the direction of the individual beams 410 is from below towards the ions 406. These directions (i.e., the direction of the global beam 420 and the direction of the individual beams 410) can be diametrically opposed, or can be two different directions that are neither diametrically opposed nor collinear with each other.

[0054] In diagram 400, the beams are shown based on their shape and / or size (e.g., laser beam spot shape and / or size) when incident on each ion 406. For example, for illustrative purposes, N ions 406 are shown, and there are N individual beams 410, each of which is elliptical in shape when incident on a respective ion 406, while the global beam 420 is elongated along the length of the ion chain such that it is wide enough to be incident across all of the N ions 406. Thus, the individual beams 410 are shown as vertically oriented elliptical beams, and the global beam 420 is shown as a horizontally elongated beam.

[0055] 5 shows a diagram 500 of an example of a dual individual geometry proposed in this disclosure, where the global beam 420 of FIG. 4 is replaced by a second set of individual addressing beams. In this example, a first set of N individual beams 510 that individually address each of the N ions 506 (i.e., qubits) in the ion chain come in from one direction, in this case from below towards the ions 506. A second set of N individual beams 520 that individually address each of the N ions 506 in the ion chain come in from another direction, in this case from above towards the ions 506. These directions (i.e., the direction of the individual beams 510 and the direction of the individual beams 520) can be diametrically opposed, or can be two different directions that are not diametrically opposed and not collinear with each other.

[0056] Individual beams 510 and 520 are shown as having an elliptical shape (eg, a laser beam spot shape) because that is their shape when incident on respective ions 506 .

[0057] As mentioned above, the individual addressing beams shown in Figures 4 and 5 can be elliptical light beams, i.e., the laser beam spot shape is elliptical. Other types of light beams, such as circular beams, can also be used. Therefore, any QIP system used to implement the type of geometry described in connection with Figures 4 and 5 must be configured to handle elliptical light beams.

[0058] As mentioned above, there are several advantages to the geometry shown in Figure 5. Some of these advantages, and techniques for achieving them, are described in more detail below in conjunction with Figures 6-15.

[0059] 6 shows diagrams 600 and 650 illustrating examples of crosstalk differences in different geometries. Diagram 600 (left side of the figure) illustrates the case of a dual individual geometry (see, e.g., FIG. 5), and diagram 650 (right side of the figure) illustrates the case of an individual-global geometry (see, e.g., FIG. 4), in which qubit crosstalk is reduced compared to the individual-global geometry.

[0060] In each diagram of FIG. 6, it is the central ion that is addressed by the individual beam. The crosstalk is proportional to the intensity of the laser beam incident on the ions that are not addressed by the individual beam, in this case the ions to the left and right of the central ion. In other words, if the laser intensity of both the individual and global laser beams aimed at the central ion overlaps with the neighboring ions to the left and / or right of the central ion, the neighboring ions may receive an unintended amount of laser intensity (crosstalk) from the individual and global beams when addressing the central ion.

[0061] Diagram 600 in FIG. 6 shows an example of a dual individual geometry, where one individual beam 610 (solid line) is incident on the central ion 606b from one direction (e.g., from the back of the figure) and another individual beam 620 (dashed line) is incident on the central ion 606b from another direction (e.g., from the front of the figure). In this example, the individual beams 610 and 620 are elliptical light beams with substantially the same orientation (e.g., vertical orientation), shape, and size, and are shown in the figure as slightly different only to distinguish one from the other. The individual beams 610 and 620 are intended to substantially overlap (e.g., have substantially the same orientation, shape, and size) at the point where they both are incident on the central ion 606b. Due to this geometry, only a small amount of the laser intensity from both beams is incident on the adjacent ions (e.g., the left ion 606a and the right ion 606c). That is, only a small amount of the beam used to individually address the center ion 606b overlaps with the left ion 606a and the right ion 606c, thereby reducing or minimizing crosstalk in adjacent ions resulting from addressing the center ion.

[0062] Diagram 650 in FIG. 6 illustrates a conventional individual-global geometry, where one individual beam 660 (solid line) is incident on the central ion 606b from one direction (e.g., from the back of the figure) and a global beam 670 (dashed line) is incident on the central ion 606b from another direction (e.g., from the front of the figure). In this example, the individual beam 660 and the global beam 670 do not have substantially the same orientation, shape, and size. For example, the individual beam 660 is shown to be oriented vertically, while the global beam 670, which extends along the ion chain as described above, is shown to have a different orientation. The individual beam 660 can be an elliptical light beam. Due to this geometry, crosstalk tends to be greater in the individual-global geometry than in the dual individual geometry, since only a small amount of laser intensity from the individual beam 660 is incident on adjacent ions (e.g., the left ion 606a and the right ion 606c) as shown by the small overlap, while the full intensity of the global beam 670 is incident on adjacent ions, resulting in the global beam 670 overlapping with the left ion 606a and the right ion 606c.

[0063] 7 shows diagrams 700 and 750 illustrating examples of power efficiency differences in different geometries. Diagram 700 (e.g., on the left side of the figure) illustrates the case of a dual-discrete geometry, and diagram 750 (e.g., on the right side of the figure) illustrates the case of a discrete-global geometry, where the dual-discrete geometry is more efficient and therefore more scalable.

[0064] 7, individual beams 710a, 710b, and 710c (solid lines) are incident on ions 706a, 706b, and 706c, respectively, from one direction (e.g., from the back of the figure), and individual beams 720a, 720b, and 720c (dashed lines) are incident on ions 706a, 706b, and 706c, respectively, from another direction (e.g., from the front of the figure). In this example, individual beams 710a, 710b, and 710c and their corresponding individual beams 720a, 720b, and 720c are elliptical light beams having substantially the same orientation (e.g., vertical orientation), shape, and size, and are shown in the figures as slightly different only to distinguish one from the other. The individual beams 710a, 710b, and 710c and their corresponding individual beams 720a, 720b, and 720c are intended to substantially overlap (e.g., have substantially the same orientation, shape, and size) at the point where they are incident on the respective ions 706a, 706b, 706c. The dual individual geometry shown in diagram 700 allows for beam shaping to provide optimal laser power delivery to the appropriate ion locations without power being wasted between ions or applied to the wrong ions.

[0065] In diagram 750 of FIG. 7, individual beams 760a, 760b, 760c (solid lines) are incident on ions 706a, 706b, 706c, respectively, from one direction (e.g., the back of the figure), and a global beam 770 (dashed line) is incident on all ions 706a, 706b, 706c from another direction (e.g., the front of the figure). In this example, the individual beams 760a, 760b, and 760c have substantially the same orientation (e.g., vertical orientation), shape, and size. Meanwhile, the global beam 770 extends along the ion chain and is shown to have a different orientation, shape, and size than the individual beams. In diagram 750, the arrows indicate wasted power delivered to the vacuum space between the ions in the chain.

[0066] In an example showing the difference in power efficiency, when the beam diameter of the individual beams is 1.5 mm and the ion spacing is 4.5 mm, the overhead of the individual-global geometry is 100%. Thus, in general, the individual-global geometry may tend to be less efficient than the dual individual geometry because less power is wasted. However, the additional losses from generating an additional set of individual beams in the dual individual geometry may make the individual-global geometry more power efficient.

[0067] 8 shows diagrams 800 and 850 illustrating examples of the difference in spontaneous emission and idle errors in different geometries. Diagram 800 (e.g., on the left side of the figure) illustrates the case of a dual individual geometry, and diagram 850 (e.g., on the right side of the figure) illustrates the case of an individual-global geometry.

[0068] The diagram 800 of FIG. 8 shows ions 806a, 806b, and 806c. The central ion, ion 806b, is addressed by an individual beam 810 (solid line) from one direction (e.g., from the back of the figure) and an individual beam 820 (dashed line) from another direction (e.g., from the front of the figure). In this example, the individual beams 810 and 820 are elliptical light beams with substantially the same orientation (e.g., vertical orientation), shape, and size, and are shown slightly different in the figure only to be able to distinguish one from the other. The neighboring ions, left ion 806a and right ion 806c, are not addressed by individual beams.

[0069] Diagram 850 of Figure 8 also shows ions 806a, 806b, and 806c, with the central ion 806b being addressed by an individual beam 860 (solid line) from one direction, and all ions being incident on a global beam 870 from another direction. The individual beams 860 are elliptical beams of light, and the global beam 870 extends along the ion chain and is shown to have a different orientation, shape, and size than the individual beams 860.

[0070] The use of the dual individual geometry of diagram 800 allows beam shaping to be implemented to help minimize light incident on adjacent ions, and therefore, dual individual geometry can mitigate the impact of fundamental limitations on Raman addressing systems.

[0071] In the individual-global geometry of diagram 850, the total intensity of the global beam 870 is incident on all ions in the chain for all Raman operations. This unwanted intensity can cause so-called idle errors, or errors in qubits when no operations are ostensibly being applied, including unwanted shifts and spontaneous emissions, which limit the fidelity and performance of quantum computing. In this example, spontaneous emissions are indicated by the black arrows, which represent scattering of photons by neighboring ions (which represent all ions in the chain). This error scales with the number of ions in the chain (e.g., size of the quantum computer), so as the system scales, this error gets worse.

[0072] The dual individual geometry of diagram 800 also allows for optimizing the spontaneous emission from the target qubit by balancing the strength on both sides, optimizing the labyrinth rate (interaction strength) per unit of spontaneous emission.

[0073] 9 shows a diagram 500 illustrating an example of a schematic of a dual separate Raman system. This implementation is for illustrative purposes and several variations are possible within the scope of this disclosure.

[0074] The dual separate Raman system includes two symmetrical sections or parts: a left Raman (left half of diagram 900) and a right Raman (right half of diagram 900). Because the left and right halves of the system in diagram 900 are symmetrical, the operation and configuration of the two halves of the dual separate Raman system are substantially the same.

[0075] A laser source 950 generates a laser beam, which is split so that it can be provided as an input to both left and right Raman. For left Raman, the input laser beam is provided to a diffractive optical element (DOE) 905a, which generates an array of individual laser beams. The number of beams generated by the DOE 905a is based on the order supported by the DOE (i.e., the DOE order) and should be sufficient to allow individual addressing of the qubits 960 (e.g., an array of ions in an ion chain as described in FIG. 1). In some cases, the DOE 905a may generate more beams than the number of individual laser beams required by left Raman. The array of individual laser beams is provided to a multi-channel modulator (MCM) 915a after passing through optics 910a, which allows the spacing between the individual laser beams to match the spacing of the channels in the MCM 915a. In one example, MCM 915a may be an acousto-optic modulator (AOM) or an electro-optic modulator (EOM) and may have a sufficient number of channels to separately control each of the individual laser beams. As shown in diagram 900, MCM 915a receives channel signals (e.g., channel controls) for separately controlling each of the individual laser beams, including signals for controlling the amplitude, phase, frequency, and / or polarization of each of the individual laser beams.

[0076] After the MCM 915a, the array of individual laser beams is sent through the remainder of the left Raman, which is composed of lenses, mirrors, and several beam shaping or beam configuration devices. For example, the array of individual laser beams passes through a double telecentric zoom lens 920a, simply called a telecentric zoom lens or zoom lens, an interleaver 925a, a Dove prism 930a, and another set of lenses, mirrors, and beam shaping devices or beam configuration 935a. Finally, the array of individual laser beams is imaged onto a qubit 960. When the qubit is composed of a chain of ions or other atom-based qubits, the imaging of the array of individual laser beams is, for example, as shown in FIG. 5.

[0077] Left Raman is such that MCM 915a, zoom lens 920a, and interleaver 925a, along with one or more optical components, form the first or left optical path of the overall Raman system. These components are configured to receive an array of individual laser beams (e.g., from DOE 905a) and condition and / or configure the array of individual laser beams such that each beam in the array is used to individually address a respective quantum bit in quantum bits 960 (e.g., each ion in an ion chain).

[0078] In addition to mirrors and lenses, the right Raman includes a DOE 905b, an optical system 910b, an MCM 915b, a zoom lens 920b, an interleaver 925b, a Dove prism 930b, and another set of lenses, mirrors, and beam shaping or beam configuration devices 935b. As mentioned above, the right Raman and the left Raman are symmetrical and their operation and configuration are substantially the same. Thus, corresponding components or elements of both halves also have substantially the same operation and configuration.

[0079] The right Raman is such that MCM 915b, zoom lens 920b, and interleaver 925b, along with one or more optical components, form the second or right optical path of the overall Raman system. These components are configured to receive an array of individual laser beams (e.g., from DOE 905b) and condition and / or configure the array of individual laser beams such that each beam in the array is used to individually address a respective qubit in qubit 960 (e.g., each ion in an ion chain). The array of individual laser beams provided by the left Raman is imaged onto qubit 960 in one direction, and the array of individual laser beams provided by the right Raman is imaged onto qubit 960 in another direction. For example, the two directions can be opposite directions, but need not be so limited.

[0080] Part of the Raman system can be created or implemented in a number of ways. For example, a combination of DOE and MCM can be created by instead using individual fiber-coupled modulators and coupling them into a fiber array. The output of the fiber array is then used as the source of an array of individual laser beams, which are the input to a zoom lens.

[0081] As mentioned above, the left and right Raman of a dual individual Raman system must generate an array of individual beams that are closely matched in spacing, telecentricity, polarization, and spatial profile in the ion plane. The triple spacing of the two sets of individual Raman beams and the ion chains must be matched, so that small imperfections in the magnification of the optics cannot be accommodated by the ion chains alone (as in the case of a global Raman beam).

[0082] Therefore, to address the additional degrees of freedom (DOF) required to achieve such alignment, the present disclosure proposes using devices that enable various types of beam manipulation. One such device is called a reflective Dove prism, or simply a Dove prism, examples of which are Dove prisms 930a and 930b. More information regarding Dove prisms is provided below and in, for example, U.S. Patent No. 11,322,343, entitled "Optical Alignment Using Reflective Dove Prisms," issued May 3, 2022, the contents of which are incorporated herein by reference. Another such device is a telecentric zoom lens, or simply a zoom lens, examples of which are zoom lens 920a and zoom lens 920b.

[0083] 10A and 10B show an example of a reflective Dove prism that provides a degree of roll freedom to an array or fan of individual beams. FIG. 10A shows a diagram 1000 illustrating an example of a reflective element or structure (e.g., a mirror) to replicate the functionality of a Dove prism (e.g., Dove prisms 930a and 930b). In contrast to refractive optics, the use of reflective optics involves a change in the direction of light at an interface between two different media, where the light returns to the original medium. In reflective optics, the light does not need to enter a second medium to change its trajectory.

[0084] In the example of diagram 1000, an input beam 1030 (or an input image) is directed to a first reflecting structure 1010a, from which it is reflected towards a second reflecting element 1010b, which in turn reflects towards a third reflecting structure 1010c, which in turn reflects back towards the propagation axis 1040 of the original input beam 1030. The first reflecting structure 1010a and the third reflecting structure 1010c are angled with the same inclination with respect to the propagation axis 1040. The second reflecting structure 1010b is essentially used to retro-reflect the input beam 1030 in a third dimension to create a periscope effect. When the arrangement of reflecting structures is rotated about the central pivot point 1020, the input beam 1030 is tilted by twice the rotation angle of the entire assembly. The rotation angle can be small, for example, the rotation angle can be less than 1 degree. The rotation angle can be in a positive direction (e.g., one direction) or a negative direction (e.g., the opposite direction) and can range up to 90 degrees in either direction. The rotation angle can be controlled to an accuracy of, for example, one tenth of a degree (0.1 degree) or better.

[0085] Referring now to FIG. 10B, a diagram 1050 is shown showing a perspective view of a system or assembly having a housing 1060 for mounting or positioning the reflecting structures 1010a, 1010b, and 1010c of the diagram 1000 of FIG. 10A. The input beam 1030 (or input image) is directed to the first reflecting structure 1010a. For example, the housing 1060 may have a lower portion where the first reflecting structure 1010a and the third reflecting structure 1010c are mounted at a right tilt or angle, and an upper portion where the second reflecting structure 1010b is mounted. The reflecting structures that are separate but embedded in the housing 1060 may be made of a material different from the material used to manufacture the housing 1060. The housing 1060 is also configured to provide a free path for reflections to occur. It should be understood that the housing 1060 is provided as an example, and many different configurations, shapes, or form factors may be used to provide the same or similar functionality as the housing 1060.

[0086] Figure 11 shows a diagram 1100 illustrating a possible implementation of a simplified telecentric zoom lens schematic for use in a dual discrete geometry. Examples of such telecentric zoom lenses are zoom lens 920a and zoom lens 920b in Figure 9. The use of telecentric zoom lenses can provide the appropriate spacing flexibility required for a dual discrete geometry.

[0087] A telecentric zoom lens includes two sets of lenses. The outer two lens sets are lenses 1110 and 1120. Lenses 1110 and 1120 are fixed, i.e., they are not configured to move or slide along the optical axis 1150. Therefore, the outer lens distance between the two outer lenses is fixed.

[0088] Also part of a telecentric zoom lens is a set of two lenses inside the lenses 1130 and 1140. The inner lenses 1130 and 1140 are configured to move together, i.e., move or slide together along the optical axis 1150. The inner lens distance between the two inner lenses is also fixed. In other embodiments, the inner lenses 1130 and 1140 are configured to be fixed and the outer lenses 1110 and 1120 are configured to move together.

[0089] In one aspect, each lens in the set of two outer lenses may be implemented using a single lens, and each lens in the set of two inner lenses may be implemented using a compound lens. Other implementations of the lenses in the inner and outer sets may also be used. For example, any one of the lenses in the inner or outer sets may be a single lens or a compound lens depending on the requirements of the system.

[0090] FIG. 12 shows a diagram 1200 showing an isometric view of the mechanical implementation of the simplified telecentric zoom lens of FIG. 11. The telecentric zoom lens includes a base 1210, a housing 1230 that is attached to the base 1210 and holds the outer lens pair (e.g., lenses 1110 and 1120 of FIG. 11) in a fixed position, and a movable part or carriage 1240 that slides along the housing 1230 and holds the inner lens pair (e.g., lenses 1130 and 1140 of FIG. 11). The slide of the carriage 1240 is a linear slide that can be manual or motorized. The two outer lenses are held together by the housing 1230 and are referenced to the rest of the optical system (e.g., the respective Raman system of FIG. 9). Linear

[0091] In another implementation of a simplified telecentric zoom lens, the inner lens pair may be fixed in position and the outer lens pair is configured to move together.

[0092] One challenge in using the dual individual geometry described herein is increased sensitivity to beam pointing noise (e.g., noise or variations in beam pointing direction). Global beam geometries are less sensitive to pointing due to the large size of the global light beam compared to atom-based qubits. Since only the individual beams are significantly affected by pointing noise (the effect of the global beam is negligible), dual individual geometries increase this by a factor of two, impacting qubit operations by a factor of √2. One way to mitigate this problem is to increase the spot size of the individual beams. This is a fundamental tradeoff with crosstalk, and an optimal value can be chosen, for example, as a percentage of the ion spacing. However, conventional MCM configurations are limited by another factor, namely the size of the beam in the MCM device as a percentage of the channel spacing, which is later reimaged onto the ion chain.

[0093] The MCM device parameters (e.g., AOM device parameters), i.e., the MCM channel spacing and Gaussian beam size that the MCM is designed to handle, set the beam array properties in the ion chain because in conventional imaging systems, the Gaussian and geometric beam properties are coupled to each other (known as optical invariance or etendue). As an example, an MCM device with a channel spacing of 450 mm and a designed Gaussian beam size of 75 μm has a spacing-to-size ratio of 6. A typical ion chain spacing is 4.5 μm, which means that the output beam array optics of the Raman system must reduce the MCM spacing by a factor of 100 (i.e., from 450 mm to 4.5 mm) to re-image the light beam onto the ion chain. This means that for an ion chain spacing of 4.5 μm, the light beam size is 0.75 μm (i.e., a factor of 100 reduction from 75 μm). One example of a more preferred ratio of ion chain separation to ion chain beam size is 3, ie, in the above example, for an ion chain separation of 4.5 μm, an exemplary beam size is about 1.5 μm.

[0094] The required magnification (e.g., 2x) can be achieved using an interleaver as shown in Figures 13A, 13B, and 14 below. Figure 13A shows a diagram 1300 illustrating an example of a schematic of an interleaver function. Here, an input array of light beams is split in two, the left half of the light beams is represented by dashed lines, and the right half of the light beams is represented by dotted lines, which are then recombined into an output array of light beams, an interferometer-like setup 1305 with matched path lengths on each leg or path. It is important to note that this is necessary for setups using pulsed lasers, but may not be a requirement for other setups, such as setups using continuous wave (CW) Raman lasers. In this example, the left half of the light beams passes through a first path (path 1) that includes optical elements 1315, 1320, and 1335. The right half of the light beams passes through a second path (path 2) that includes optical elements 1325, 1330, and 1335. This effectively shifts the left side so that it overlaps with the right side in an interdigitated geometry, which leaves the Gaussian beam characteristics unchanged while reducing the beam array spacing by the appropriate factor.

[0095] Similar functionality provided by the interleaver of diagram 1300 of FIG. 13A can be achieved with an interleaver configuration with additional mirrors, an example of which is shown in diagram 1350 of FIG. 13B. Again, an input array of light beams is split in two, the left half of the light beams represented by dashed lines and the right half of the light beams represented by dotted lines, which are then recombined into an output array of light beams, an interferometer-like setup 1310 with matched path lengths on each leg or path. In this example, the left half of the light beams passes through a first path (path 1) that includes optical elements 1315, 1320, and 1335. The right half of the light beams passes through a second path (path 2) that includes optical elements 1325, 1340, 1345, and 1335. This effectively flips the left side and overlaps with the right side in an interdigitated geometry. This leaves the Gaussian beam characteristics unchanged, and reduces the beam array spacing by the appropriate factor.

[0096] 14 shows a diagram 1400 illustrating an example of the numbering of individual laser / light beams and their respective ions applied from one side of a Raman system after an interleaving process has been performed by one of the interleavers described herein or some other interleaver configuration. In this example, the ions in the ion chain are numbered 1 to 32 and the laser / light beams are labeled to indicate their DOE orders -16 to 0. As mentioned above, diagram 1400 only shows the light beams from one side of the Raman system as they are imaged onto the ions / qubits; a similar set of light beams is imaged from the other side of the Raman system but is not shown.

[0097] FIG. 15 shows a flow chart of a method 1500 for dual individual addressing of atom-based qubits in a Raman system.

[0098] At 1510, a first MCM, a first telecentric zoom lens, and a first interleaver that together with one or more optical components form a first optical path are provided. In one example, the first optical path may refer to an optical path associated with a left Raman portion of the Raman system shown in FIG.

[0099] At 1520, a second MCM, a second telecentric zoom lens, and a second interleaver are provided that together with one or more optical components form a second optical path. In one example, the second optical path may refer to an optical path associated with the right Raman portion of the Raman system shown in FIG.

[0100] At 1530, the first optical path receives the first array of beams and modulates or steers the first array of beams such that each beam in the first array of beams individually addresses a respective atom-based quantum bit in the chain (e.g., a respective quantum bit among quantum bits 960 in FIG. 9 ) from a first direction.

[0101] At 1540, a second optical path receives a second array of beams and modulates or steers the second array of beams such that each beam in the second array of beams individually addresses a respective atom-based quantum bit in the chain from a second direction.

[0102] In one aspect of method 1500, each beam in the array of first beams is an elliptical beam, each beam in the array of second beams is an elliptical beam, and corresponding elliptical beams from the array of first beams and the array of second beams substantially overlap.

[0103] In one embodiment of method 1500, method 1500 further includes independently controlling, at each channel of the first multi-channel MCM, one or more characteristics of each beam of the array of first beams applied to that channel, and independently controlling, at each channel of the second multi-channel MCM, one or more characteristics of each beam of the array of second beams applied to that channel.

[0104] In one embodiment of method 1500, method 1500 further includes adjusting, by a first optical path, a beam spacing of the array of first beams to match the spacing of the atomic-based quantum bits in the chain, and adjusting, by a second optical path, a beam spacing of the array of second beams to match the spacing of the atomic-based quantum bits in the chain.

[0105] In one aspect of method 1500, the first array of beams includes a subset of first beams and a subset of second beams, and the second array of beams includes the subset of first beams and the subset of second beams, and method 1500 further includes adjusting positions of beams in the first array of beams such that beams from the first subset of beams and beams from the second subset of beams are alternated by a first interleaver and have reduced beam spacing at an output of the first interleaver, and adjusting positions of beams in the second array of beams such that beams from the first subset of beams and beams from the second subset of beams are alternated by a second interleaver and have reduced beam spacing at an output of the second interleaver.

[0106] The preceding description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the common principles defined herein can be applied to other variations without departing from the scope of the disclosure. Furthermore, although elements of the described aspects may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is expressly stated. Furthermore, unless otherwise stated, all or a portion of any aspect can be utilized with all or a portion of any other aspect. Thus, the disclosure is not intended to be limited to the examples and designs described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. 1. A Raman system for dual individual addressing of atom-based quantum bits, comprising: a first multi-channel modulator (MCM), a first telecentric zoom lens, and a first interleaver, which together with one or more optical components form a first optical path of the Raman system and are configured to receive an array of first beams and condition the array of first beams such that each beam in the array of first beams individually addresses a respective atom-based quantum bit in a chain from a first direction; a second MCM, a second telecentric zoom lens, and a second interleaver that together with one or more optical components form a second optical path of the Raman system and are configured to receive a second array of beams and condition the second array of beams such that each beam in the second array of beams individually addresses a respective atom-based quantum bit in the chain from a second direction, different from the first direction; A Raman system comprising:

2. each beam in the first array of beams is an elliptical beam; each beam in the second array of beams is an elliptical beam; corresponding elliptical beams from the first array of beams and the second array of beams substantially overlap.

10. The Raman system of claim 1 .

3. The Raman system of claim 2 , wherein the elliptical beam is a Gaussian beam.

4. The Raman system of claim 1 , wherein the first optical path and the second optical path are symmetric.

5. A laser source; a first diffractive optical element (DOE) and a second DOE; wherein the laser source is configured to generate a single beam, the single beam being split and a portion being provided to the first DOE, the first DOE configured to generate the array of first beams from the portion of the single beam, and a remaining portion of the single beam being provided to the second DOE, the second DOE configured to generate the array of second beams from the remaining portion of the single beam.

10. The Raman system of claim 1 .

6. the first MCM is a first multi-channel acousto-optic modulator (AOM); the second MCM is a second multi-channel AOM; 10. The Raman system of claim 1 .

7. the channels in the first multi-channel AOM include one channel for each beam in the first array of beams, each channel in the first multi-channel AOM configured to independently control one or more properties of the respective beam of the first array of beams applied to the channel; the channels in the second multi-channel AOM include one channel for each beam in the second set of beams, and each channel in the second multi-channel AOM is configured to independently control one or more characteristics of the respective beam of the array of first beams applied to the channel; 7. The Raman system of claim 6.

8. the first array of beams received by the first optical path has a beam spacing that matches a spacing between channels in the first multi-channel AOM; the second array of beams received by the second optical path has a beam spacing that matches a spacing between channels in the second multi-channel AOM; the first optical path is configured to adjust the beam spacing of the array of first beams to match a spacing of the atomic-based quantum bits in the chain; the second optical path is configured to adjust the beam spacing of the array of second beams to match the spacing of the atom-based quantum bits in the chain.

7. The Raman system of claim 6.

9. the first optical path is further configured to adjust beam sizes of the beams in the first array of beams according to an optimal size of the atom-based quantum bits in the chain; the second optical path is further configured to adjust beam sizes of the beams in the second array of beams according to the optimal sizes of the atom-based quantum bits in the chain.

9. The Raman system of claim 8.

10. each of the first telecentric zoom lens and the second telecentric zoom lens has an outer lens pair and an inner lens pair; 2. The Raman system of claim 1 , wherein the outer lens pair are fixed in position and the inner lens pair are configured to move together to adjust the optical properties, or the inner lens pair are fixed in position and the outer lens pair are configured to move together to adjust the optical properties.

11. the first array of beams includes a subset of first beams and a subset of second beams, and the first interleaver is configured to optically adjust positions of the beams within the first array of beams such that beams from the subset of first beams and beams from the subset of second beams are interleaved and have reduced beam spacing at an output of the first interleaver; the second array of beams includes a subset of first beams and a subset of second beams, and the second interleaver is configured to optically adjust positions of the beams in the second array of beams such that beams from the subset of first beams and beams from the subset of second beams are interleaved and have reduced beam spacing at an output of the second interleaver.

10. The Raman system of claim 1 .

12. the first interleaver includes a first path for a subset of the first beams from the first array of beams and a second path for a subset of the second beams from the first array of beams; the second interleaver includes a first path for a subset of the first beams from the second array of beams and a second path for the subset of the second beams from the second array of beams.

12. The Raman system of claim 11.

13. the first optical path is further formed by a first reflective Dove prism; the second optical path is further formed by a second reflecting Dove prism; 10. The Raman system of claim 1 .

14. 2. The Raman system of claim 1 , wherein the first direction for each beam in the array of first beams to individually address each of the atom-based quantum bits in the chain is opposite to the second direction for each beam in the array of second beams to individually address each of the atom-based quantum bits in the chain.

15. 10. The Raman system of claim 1 , wherein each of the atom-based qubits in the chain is an ion.

16. 1. A method for dual individual addressing of atom-based quantum bits in a Raman system, comprising: providing a first multi-channel modulator (MCM), a first telecentric zoom lens, and a first interleaver that together with one or more optical components form a first optical path; forming a second optical path with one or more optical components, comprising a second MCM, a second telecentric zoom lens, and a second interleaver; receiving an array of first beams via the first optical path and adjusting the array of first beams via the first optical path such that each beam in the array of first beams individually addresses a respective atom-based quantum bit in a chain from a first direction; receiving a second array of beams via the second optical path and adjusting the second array of beams via the second optical path such that each beam in the second array of beams individually addresses a respective atom-based quantum bit in the chain from a second direction; A method comprising:

17. each beam in the first array of beams is an elliptical beam; each beam in the second array of beams is an elliptical beam; corresponding elliptical beams from the first array of beams and the second array of beams substantially overlap.

17. The method of claim 16.

18. Independently controlling, at each channel of the first multi-channel MCM, one or more characteristics of a respective beam of the first array of beams applied to the channel; Independently controlling, at each channel of the second multi-channel MCM, one or more characteristics of each beam of the second array of beams applied to the channel; 20. The method of claim 16, further comprising:

19. adjusting, via the first optical path, a beam spacing of the array of first beams to match a spacing of the atom-based quantum bits in the chain; adjusting, via the second optical path, a beam spacing of the array of second beams to match a spacing of the atom-based quantum bits in the chain; 20. The method of claim 16, further comprising:

20. the array of first beams includes a subset of first beams and a subset of second beams; the array of second beams includes a subset of first beams and a subset of second beams; The method comprises: adjusting positions of the beams in the first array of beams such that beams from the subset of first beams and beams from the subset of second beams are interleaved by the first interleaver and have reduced beam spacing at an output of the first interleaver; adjusting positions of the beams within the array of second beams such that the beams from the subset of first beams and the beams from the subset of second beams are interleaved by the second interleaver and have reduced beam spacing at an output of the second interleaver; 20. The method of claim 16, further comprising:

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