Detecting lost or unwanted reordering of quantum objects

Abstract

Various embodiments provide a method, apparatus, system, or computer program product for performing detection of loss of a quantum object. The method, performed by a controller of a quantum computer, includes controlling one or more voltage sources to cause a quantum object confinement device to confine a crystal of a quantum object, the crystal of the quantum object (i) including at least one of (a) a first species quantum object or (b) a second species quantum object and (ii) defining a crystal axis aligned along an RF null axis of the quantum object confinement device; causing at least one control electrode of a plurality of control electrodes to provide at least one first control signal, the at least one first control signal causing the at least one control electrode to generate a pushing field configured to rotate the crystal axis of the quantum object relative to the RF null axis.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Patent Application No. 18 / 454,336, filed August 23, 2023, which claims priority to U.S. Patent Application No. 63 / 408,753, filed September 21, 2022, the contents of which are incorporated herein by reference in their entireties.

[0002] Various embodiments relate to devices, systems, and methods related to detecting the loss or unwanted reordering of quantum objects within quantum object confinement devices. For example, some exemplary embodiments relate to detecting the loss of a qubit in a quantum computer. [Background technology]

[0003] Quantum computing is the use of quantum phenomena such as superposition and entanglement to perform calculations. In particular, quantum bits (qubits) are acted upon to cause and / or control the evolution of the qubit's quantum state to perform one or more calculations. Trapped ion quantum computers utilize ions confined by an ion trap as data qubits used for such calculations. However, in various scenarios, ions may interact with, for example, background gas and be expelled from the ion trap. Thus, loss or unwanted reordering of ions may occur during or even before a calculation, leading to errors in the resulting calculation. Effective and accurate detection of loss or unwanted reordering of ions during a calculation in an ion trap without introducing qubit errors or otherwise adversely affecting the ions is difficult if no loss has occurred. Through hard work, ingenuity, and innovation, many of the shortcomings of such conventional detection techniques have been overcome by developing solutions constructed in accordance with embodiments of the present invention, many examples of which are described in detail herein. Summary of the Invention [Means for solving the problem]

[0004] Exemplary embodiments provide methods, systems, devices, computer program products, etc. for determining, identifying, and / or detecting when a quantum object is missing from an expected location of the quantum object defined by a quantum object confinement device. Various embodiments correspond to a quantum computer, such as, for example, a quantum charge-coupled device (QCCD)-based quantum computer, and determining and / or identifying when a quantum object is missing from an expected location of the quantum object defined by the quantum object confinement device. For example, the qubits of the quantum computer may be atoms and / or ions or other quantum particles that may be part of a crystal and / or group of quantum objects. In various embodiments, the quantum object is captured and / or confined within a quantum object confinement device, such as an ion trap, a surface ion trap, etc.

[0005] In various embodiments, to accurately detect a quantum object without introducing qubit errors or otherwise adversely affecting the quantum state of at least one qubit when no loss has occurred, loss or reordering of the quantum object from the confinement device is detected before every readout of the quantum state of at least one qubit of the quantum object's crystal. For example, a push field and / or an oscillating potential may be generated to rotate the crystal axis of the quantum object's crystal relative to the RF null axis of the confinement region so that the crystal axis has a vector component transverse to the RF null axis. When a quantum object within the confinement region is not positioned on the RF null axis, the quantum object experiences an oscillating radial force as a result of a trapping pseudopotential. This oscillating radial force causes the quantum object to be positioned off the RF null axis and to exhibit oscillations and / or small reciprocating motions. When a detection beam is provided that is either frequency-modulated with the rf drive frequency or detuned from a particular transition by the rf drive frequency of the second species of quantum object and incident on the rotated crystal of quantum objects, the vibrational motion of the second species of quantum object causes the detection beam to resonate with the particular transition. In various embodiments, the particular transition is a micromotion sideband transition corresponding to the vibration and / or small back-and-forth motion of the quantum object. Thus, the second species of quantum object fluoresces and / or emits stimulated emission in response to the detection beam being incident on the second species of quantum object. The detection beam is off-resonant from the transition from the qubit space and / or ground state of the first species of quantum object. The stimulated emission may be detected, and it may be determined whether both members of the crystal of quantum objects are present and whether the crystal of quantum objects has experienced ion loss or undesired rearrangement.

[0006] According to a first aspect, a method is provided that is executed by a controller of a quantum computer. In an exemplary embodiment, the method includes the steps of controlling one or more voltage sources to cause a quantum object confinement device to confine a crystal of a quantum object, the quantum object confinement device including: (a) one or more RF electrodes that define a radio frequency (RF) null axis of the quantum object confinement device; and (b) a plurality of control electrodes, the crystal of the quantum object including (i) at least one of (a) a first species of quantum object or (b) a second species of quantum object and (ii) defining a crystal axis that is aligned along the RF null axis of the quantum object confinement device; causing at least one control electrode of the plurality of control electrodes to provide at least one first control signal, the at least one first control signal causing the at least one control electrode to generate a pushing field configured to rotate a crystal axis of the quantum object relative to the RF null axis such that the crystal axis has a vector component transverse to the RF null axis; and generating and providing a modulated detection beam that is incident on at least a portion of the crystal of the quantum object; receiving a signal indicative of a response of the crystal of the quantum object to the modulated detection beam being incident on at least a portion of the crystal of the quantum object; and determining, based on the signal, whether both (a) a first species of quantum object and (b) a second species of quantum object are present in the crystal of the quantum object.

[0007] In an exemplary embodiment, in response to the absence of (a) the first type of quantum object or (b) the second type of quantum object, the method further includes controlling one or more voltage sources to cause the confinement device to confine a crystal of a new quantum object within the confinement device.

[0008] In an exemplary embodiment, when the second species quantum object is not detected by the modulated detection beam, a quantum object loss has occurred in the quantum object crystal, and the quantum object loss comprises the first species quantum object or the second species quantum object being missing from the quantum object confinement device.

[0009] In an exemplary embodiment, in response to the presence of both (a) a first species of quantum object and (b) a second species of quantum object, the method further includes the steps of commencing execution of a quantum circuit using the first species of quantum object within the quantum object confinement device; and, during execution of the quantum circuit, identifying a read function to be performed on the first species of quantum object, wherein causing at least one control electrode to provide at least one first control signal and causing a manipulation source to generate and provide a read beam is performed in response to the identification of the read function to be performed; and continuing execution of the quantum circuit.

[0010] In an exemplary embodiment, the method further includes receiving a read result responsive to at least partial incidence of the read beam on the quantum object of the first species, and adjusting the quantum circuit based at least in part on the read result such that the adjusted quantum circuit is executed.

[0011] In an exemplary embodiment, the first species of quantum objects are data qubits of a quantum computer, and the second species of quantum objects are sympathetic cooling ions.

[0012] In an exemplary embodiment, the first species of quantum objects are Ba ions and the second species of quantum objects are Yb ions.

[0013] In an exemplary embodiment, the modulated detection beam incident on at least a portion of the crystal of the quantum object has a wavelength tuned to a pulsating sideband of the second species of quantum object.

[0014] According to another aspect of the present disclosure, a controller is provided. In an exemplary embodiment, the controller is operably connected to one or more components of a system including a quantum object confinement device. The confinement device includes (a) one or more radio frequency (RF) electrodes that define an RF null axis of the quantum object confinement device, and (b) a plurality of control electrodes, and the one or more components of the system include (a) a voltage source and (b) a manipulation source. The controller controls the one or more voltage sources to cause the quantum object confinement device to confine a crystal of quantum objects, the crystal of quantum objects including (i) at least one of (a) a first species of quantum object or (b) a second species of quantum object, and (ii) defining a crystal axis that is aligned along the RF null axis of the quantum object confinement device; and causes at least one control electrode of the plurality of control electrodes to provide at least one first control signal, the at least one first control signal causing the at least one control electrode to align the crystal axis with the RF null axis. the quantum object is configured to generate and provide a pushing field configured to rotate a crystal axis of the quantum object relative to an RF null axis so as to have a vector component transverse to the axis; cause a manipulation source to generate and provide a modulated detection beam incident on at least a portion of the crystal of the quantum object; receive a signal indicative of a response of the crystal of the quantum object to the incidence of the modulated detection beam on at least a portion of the crystal of the quantum object; and determine, based on the signal, that both (a) a first type of quantum object and (b) a second type of quantum object are present within the crystal of the quantum object.

[0015] According to another aspect of the present disclosure, a computer program product is provided. The computer program product includes a non-transitory computer-readable medium having executable instructions stored thereon. The executable instructions, when executed by a processing device of a controller configured to control operation of one or more components of a quantum computer, cause the controller to control one or more voltage sources to cause a quantum object confinement device to confine a crystal of a quantum object, the quantum object confinement device including: (a) one or more radio frequency (RF) electrodes defining an RF null axis of the quantum object confinement device; and (b) a plurality of control electrodes, wherein the crystal of the quantum object (i) includes at least one of (a) a first species of quantum object or (b) a second species of quantum object and (ii) defines a crystal axis aligned along the RF null axis of the quantum object confinement device; and control at least one first control signal to the plurality of control electrodes. the at least one first control signal causes the at least one control electrode to generate a pushing field configured to rotate a crystal axis of the quantum object relative to the RF null axis so that the crystal axis has a vector component transverse to the RF null axis; the manipulation source is configured to generate and provide a modulated detection beam incident on at least a portion of the crystal of the quantum object; receive a signal indicative of a response of the crystal of the quantum object to the incidence of the modulated detection beam on at least a portion of the crystal of the quantum object; and determine, based on the signal, whether both (a) a first species of quantum object and (b) a second species of quantum object are present within the crystal of the quantum object.

[0016] Having thus broadly described the invention, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a schematic diagram of a detection function according to an exemplary embodiment. [Figure 2] 1 is a schematic diagram of a quantum object detection function in accordance with an example embodiment; [Figure 3] FIG. 1 is a schematic diagram of another quantum object detection function in accordance with an example embodiment; [Figure 4] 1 is a top view of an exemplary quantum object confinement device that may be used in exemplary embodiments. [Figure 5] 1 is a flowchart of various processes, procedures, and / or operations that may be performed by, for example, a controller of a quantum object confinement device to perform quantum object detection functions, according to example embodiments. [Figure 6] FIG. 1 is a schematic diagram illustrating an exemplary quantum computing system configured to perform one or more quantum object detection functions, according to various embodiments. [Figure 7] FIG. 1 is a schematic diagram of an example controller of a quantum computer configured to perform one or more quantum object detection functions, according to various embodiments. [Figure 8] FIG. 1 is a schematic diagram of an exemplary computing entity of a quantum computer system that may be used by exemplary embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0018] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all, embodiments of the invention are shown. Indeed, the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. The term "or" (also written " / ") is used herein in both a disjunctive and conjunctive sense, unless otherwise indicated. The terms "illustrative" and "exemplary" are used to be examples and do not denote a level of quality. The terms "generally," "substantially," and "about" refer to within engineering and / or manufacturing tolerances and / or the user's ability to measure, unless otherwise indicated. Like numbers refer to like elements throughout.

[0019] In various embodiments, methods, devices, systems, computer program products, etc. are provided for determining, identifying, and / or detecting when a quantum object is missing from its expected location as defined by a quantum object confinement device. In various embodiments, a crystal of quantum objects including at least one of (a) a first species of quantum object or (b) a second species of quantum object is confined within a quantum object confinement device (also referred to herein as a confinement device). In various embodiments, the first species of quantum object and the second species of quantum object are ions of two different species (e.g., with different atomic numbers), different isotopes of the same species, or use different sets of energy levels (e.g., ground state and metastable state) within the same species. In various embodiments, the first species of quantum object and the second species of quantum object are disposed within the same potential well of a confinement region and interact with each other via Coulomb repulsion between the first species of quantum object and the second species. In various embodiments, the quantum object may be part of a crystal of quantum objects that includes qubit quantum objects (e.g., qubit ions) and cooperatively cooled (SC) quantum objects (e.g., SC ions). In various embodiments, the confinement device is a trap or other device configured to confine a crystal of multiple quantum objects.

[0020] In various embodiments, the confinement device is configured to enable the performance of various functions for controlling the quantum state and / or determining the quantum state of one or more qubit quantum objects. In particular, a detection function may be used to determine whether a loss of quantum object has occurred in a crystal of quantum objects. FIG. 1 provides a schematic top view of an exemplary detection function according to example embodiments. A crystal of quantum objects 110, including at least one of (a) a first-species quantum object 110A or (b) a second-species quantum object 110B, is confined within a confinement region 100 of the confinement device. The first-species quantum object 110A and the second-species quantum object 110B are disposed within the same potential well created by the confinement device and interact with each other via Coulomb repulsion 180 between the first-species quantum object 110A and the second-species quantum object 110B. The exemplary confinement device includes at least one radio frequency (RF) electrode and multiple control electrodes. In various embodiments, at least one RF electrode generates a trapping field configured to confine quantum object crystal 110 within confinement region 100 of the confinement device. At least one RF electrode defines an RF null axis 105 of confinement region 100. In exemplary embodiments, RF null axis 105 is a longitudinal axis of at least a portion of confinement region 100. Generally, quantum object crystal 110 is positioned and / or aligned along RF null axis 105 such that a crystal axis 190 defined by the quantum object crystal is substantially aligned with RF null axis 105.

[0021] When a read function is performed to determine the quantum state of the qubit quantum object, a read beam 115 is provided to the confinement region 100 such that the read beam 115 is at least partially incident on the first-species quantum object 110A. In various embodiments, the read beam 115 is incident on the first-species quantum object at a read incidence angle α. In various embodiments, the read beam 115 is a laser beam characterized by a frequency / wavelength that resonates with a specific transition of the first-species quantum object 110A. For example, the specific transition may be a transition from a first state (e.g., qubit state 1) to another state (e.g., qubit state 0 or another quantum state of the quantum object). When the read beam 115 is incident on the first-species quantum object 110A and the quantum object is in the first state, the first-species quantum object 110A fluoresces by emitting stimulated emission 120. In various embodiments, the stimulated emission 120 is emitted by the first-species quantum object 110A at various emission angles θ. At least a portion of the stimulated emission 120 is detected by detector 125. In various embodiments, detector 125 is in communication with a controller and / or other computing entity configured to receive an indication of the detection of the stimulated emission 120 by detector 125.

[0022] A qubit may be read and / or detected by providing a read beam (e.g., a laser beam having a frequency / wavelength that is resonant with a particular quantum transition of the quantum object being used as the qubit) incident on the qubit (e.g., quantum object) being read. For example, a qubit (e.g., quantum object) is in one state (e.g., state 1) when it fluoresces in response to the read beam being incident on that qubit, and is in another state (e.g., state 0) when the qubit (e.g., quantum object) does not fluoresce in response to the read beam being incident on that qubit. For example, the read beam may be configured to stimulate emission of a particular frequency / wavelength by the qubit (e.g., quantum object) when the qubit is in a particular state, and not stimulate emission of the particular frequency / wavelength when the qubit is not in the particular state.

[0023] However, in various scenarios, the first type quantum objects and / or the second type quantum objects may move away from, exit, or swap places with the confinement region of the confinement device. For example, collisions between background atoms and the first type quantum objects or the second type quantum objects may cause the first type quantum objects or the second type quantum objects to be expelled from the confinement region of the confinement device. Performing a quantum computation with one or more quantum objects missing from the quantum confinement device or in the wrong order may result in an erroneous computation. For example, when attempting to read and / or determine the quantum state of a quantum object that is actually missing from the confinement device, the read operation may result in determining that the quantum object is in a non-fluorescent state, which may not be an accurate representation of what state the quantum object would be in if it were present. In various embodiments, the first type quantum objects are configured to be data qubits of a quantum computer, and the second type quantum objects are configured to be co-cooled ions. In various embodiments, the first type quantum objects are configured to be single quantum objects used for the qubits. 171 Yb+ The quantum object of the second species may be an ion, and the quantum object of the second species may be a single electron used for co-cooling. 138 Ba + ions. A variety of other ionic species are used as the first and second species of quantum objects in various embodiments.

[0024] In various embodiments, a pushing field and / or oscillatory potential may be generated (e.g., by application of control signals to at least the RF electrode and / or at least one of the plurality of control electrodes) and experienced by quantum object crystal 110 to rotate quantum object crystal 110, which experiences the pushing field and / or oscillatory potential, relative to the RF null axis. For example, quantum object crystal is rotated such that crystal axis 190 has a vector component transverse to RF null axis 105.

[0025] When a quantum object is positioned on the RF null axis 105, the quantum object does not experience any radial force (e.g., a force in a direction substantially perpendicular to the RF null axis 105) as a result of a trapping pseudopotential created as a result of an RF voltage applied to at least one RF electrode. However, when a quantum object within the confinement region 100 is not positioned on the RF null axis 105, the quantum object experiences an oscillating radial force as a result of the trapping pseudopotential. This oscillating radial force causes a quantum object positioned off the RF null axis 105 to exhibit oscillations and / or small reciprocating motions.

[0026] When the quantum object crystal is rotated such that its crystal axis 190 has a vector component transverse (e.g., substantially perpendicular) to the RF null axis 105, Coulomb repulsion 180 between the quantum objects of the quantum object crystal 110 causes the quantum objects to push each other away from the RF null axis 105, such that the quantum objects of the quantum object crystal exhibit radial (e.g., substantially perpendicular to the RF null axis 105) oscillations and / or small reciprocating motions. The phase of the reciprocating motion may be different for ions on either side of the RF null. FIG. 2 provides a schematic diagram of a rotated quantum object crystal, where the rotated quantum object crystal defines a crystal axis 190 having a vector component transverse to the RF null axis 105. In various embodiments, a detection beam 215 is provided that is detuned from a particular transition of the second species quantum object 110B. When either a frequency-modulated or detuned detection beam 215 is incident on the rotated quantum object crystal, the vibrational motion of second species quantum object 110B causes the detection beam to be either frequency-modulated with the rf drive frequency or detuned from a particular transition by the rf drive frequency of the second species quantum object. Thus, the second species quantum object fluoresces and / or emits stimulated emission 220 in response to the incidence of detection beam 215 on the second species quantum object. Detection beam 215 is off-resonant (e.g., far off-resonant) from the qubit space and / or transition from the ground state of the first species quantum object. For example, FIG. 2 shows quantum object crystal 110 experiencing push field 130 and having detection beam 215 incident thereon, according to various embodiments of the present disclosure. The stimulated emission may be detected (e.g., by detector 125), and it may be determined that both members of the quantum object crystal are present.

[0027] 3 provides a schematic diagram of rotated quantum object crystal 110 in the absence of first-species quantum object 110A. Due to the absence of first-species quantum object 110A, second-species quantum object 110B in rotated quantum object crystal is positioned on RF null axis 105 and does not vibrate and / or exhibit small oscillations. Thus, when detection beam 215 is incident on second-species quantum object 110B, detection beam 215 is either frequency-modulated with the RF drive frequency or detuned from a particular transition by the RF drive frequency of second-species quantum object 110B, and the second-species quantum object does not fluoresce and / or emit stimulated emission 220 in response to detection beam 215 incident on the second-species quantum object. Similarly, if first-species quantum object 110A is present but second-species quantum object 110B is absent, stimulated emission 220 is not emitted when detection beam 215 is incident on quantum object crystal 110. Thus, when one or both members of the crystal of quantum objects are absent (eg, missing), stimulated emission is not detected by detector 125.

[0028] Exemplary Quantum Object Confinement Devices FIG. 4 provides a top view of an exemplary confinement device 400 that may be used to confine a crystal 110 of quantum objects. For example, in an exemplary embodiment, the confinement device is an ion trap (e.g., a surface ion trap) and the quantum objects are ions. In an exemplary embodiment, the confinement device 400 (e.g., a surface ion trap) is fabricated as part of an ion trap chip and / or as part of an ion trap device and / or package. In an exemplary embodiment, the confinement device 400 is defined at least in part by several RF electrodes 412 (e.g., 412A, 412B). In various embodiments, the confinement device 400 is defined at least in part by several sequences 414 of control electrodes (e.g., 414A, 414B, 414C). Each sequence 414 of control electrodes includes multiple control electrodes 416. In an exemplary embodiment, each control electrode 416 and / or at least a non-empty subset of the control electrodes 416 may be independently operated by application of a control signal thereto. In an exemplary embodiment, confinement device 400 is a surface Paul trap that uses symmetric RF electrodes 412. In various embodiments, RF electrodes 412 and control electrodes 416 generate a potential and / or field experienced by crystal 110 of quantum object within confinement region 100 of confinement device 400. In particular, RF electrodes 412 may be configured to define confinement region 100 of confinement device 400, and control electrodes 416 may be configured to at least partially control the movement and / or motion of the quantum object within confinement region 100.

[0029] In various embodiments, the top surface of the containment device 400 has a planarized topology. For example, the top surface of each of the several RF electrodes 412 and the top surface of each control electrode 416 of the several sequences of control electrodes may be substantially coplanar.

[0030] In various embodiments, the containment device 400 includes and / or is at least partially defined by several RF electrodes 412. The RF electrodes 412 are formed with substantially parallel longitudinal axes 411 (e.g., 411A, 411B) and with substantially coplanar upper surfaces. For example, the RF electrodes 412 are substantially parallel such that the distance between the RF electrodes 412 is approximately constant along the length of the RF electrodes 412 (e.g., the length of the RF electrodes along the longitudinal axes 411 of the RF electrodes 412). For example, the upper surfaces of the RF electrodes 412 may be substantially flush with the upper surface of the containment device 400. In an exemplary embodiment, the several RF electrodes 412 include two RF electrodes 412 (e.g., 412A, 412B). In various embodiments, the containment device 400 may include a plurality of several RF electrodes 412. For example, the confinement device 400 may be a two-dimensional ion trap including a plurality of (e.g., pairs and / or sets of) RF electrodes 412, with each of the (pairs and / or sets of) RF electrodes 412 having substantially parallel longitudinal axes 411. In an exemplary embodiment, the first of the RF electrodes 412 have longitudinal axes 411 that are substantially parallel to one another, the second of the RF electrodes 412 have longitudinal axes 411 that are substantially parallel to one another, and the longitudinal axes of the first of the RF electrodes and the second of the RF electrodes are substantially non-parallel (e.g., transverse). While FIG. 4 shows a portion of an exemplary one-dimensional and / or two-dimensional confinement device 400 having two RF electrodes 412, other embodiments may include additional RF electrodes in various configurations.

[0031] In various embodiments, two adjacent RF electrodes 412 may be separated (e.g., insulated) from one another by a longitudinal gap. In various embodiments, confinement region 100 at least partially lies on the longitudinal gap. For example, the longitudinal gap may define confinement region 100 (in one or two dimensions). In various embodiments, confinement region 100 may extend substantially parallel to longitudinal axes 411 of adjacent RF electrodes 412. For example, the longitudinal gap may extend substantially parallel to the x-axis, as shown in FIGS. 1-2 . In exemplary embodiments, the longitudinal gap may be at least partially filled with an insulating material (e.g., a dielectric material). In various embodiments, the dielectric material may be silicon dioxide (e.g., formed by thermal oxidation) and / or other dielectric and / or insulating material. In various embodiments, the longitudinal gap has a height (e.g., in the y-direction) of approximately 40 μm to 500 μm. In various embodiments, one or more sequences 414 of control electrodes (eg, second sequence 414B of control electrodes) may be disposed and / or formed within the longitudinal gap.

[0032] In exemplary embodiments, lateral gaps may exist between adjacent and / or neighboring control electrodes 416 of one or more sequences of control electrodes 414. In exemplary embodiments, the lateral gaps may be empty space and / or may be at least partially filled with a dielectric material to prevent electrical communication between adjacent and / or neighboring electrodes. In exemplary embodiments, the lateral gaps between adjacent and / or neighboring electrodes may be in the range of approximately 1-10 μm.

[0033] In an exemplary embodiment, a longitudinal gap exists between the sequence of control electrodes 414 and adjacent and / or neighboring RF electrodes 412. In an exemplary embodiment, the longitudinal gap may be at least partially filled with a dielectric and / or insulating material to prevent electrical communication between the control electrodes 416 of the sequence of control electrodes 414 and the RF electrodes 412. In an exemplary embodiment, the longitudinal gap between adjacent and / or neighboring electrodes may be in the range of about 1-10 μm.

[0034] In various embodiments, the confinement device 400 may be at least partially defined by several sequences 414 of control electrodes (e.g., a first sequence 414A of control electrodes, a second sequence 414B of control electrodes, and a third sequence 414C of control electrodes). Each sequence 414 of control electrodes is formed to extend substantially parallel to the substantially parallel longitudinal axes 411 of the RF electrodes 412. For example, the several sequences 414 of control electrodes may extend substantially parallel to the x-axis as shown in FIG. 4. In various embodiments, the several sequences 414 of control electrodes include two, three, four, and / or another number of sequences 414 of control electrodes. In an exemplary embodiment, the confinement device 400 includes a plurality of several sequences 414 of control electrodes. For example, the confinement device 400 shown is a one-dimensional ion trap including three sequences 414 of control electrodes. For example, the confinement device 400 may be a two-dimensional ion trap including a plurality of sequences 414 of control electrodes, each extending substantially parallel to the substantially parallel longitudinal axes of a corresponding number of RF electrodes 412. In an exemplary embodiment, the first sequences 414 of control electrodes extend substantially parallel to the substantially parallel longitudinal axes 411 of the first several RF electrodes 412, and the second sequences 414 of control electrodes extend substantially parallel to the substantially parallel longitudinal axes 411 of the second several RF electrodes 412, where the longitudinal axes of the first several RF electrodes and the longitudinal axes of the second several RF electrodes are substantially non-parallel (e.g., transverse). In some embodiments, each of the control electrodes 416 of the sequences 414 of control electrodes may be formed to have a substantially coplanar top surface that is substantially coplanar with the top surface of the RF electrode 412.

[0035] In an exemplary embodiment (e.g., shown in FIG. 4 ), several (e.g., pairs) of RF electrodes 412 may be formed between a first sequence of control electrodes 414A and a third sequence of control electrodes 414C, with a second sequence of control electrodes 414B extending along the longitudinal gap between the RF electrodes 412. For example, each sequence of control electrodes 414 may extend in a direction substantially parallel to the longitudinal axis 411 of the RF electrode 412 (e.g., the x-direction). In various embodiments, the top surface of the sequence of control electrodes 414 is substantially coplanar with the top surface of the RF electrode 412.

[0036] In various embodiments, RF signals may be applied to RF electrodes 412 to generate electric and / or magnetic fields that act to maintain quantum objects (e.g., ions) trapped within confinement device 400 in directions transverse to the longitudinal direction of confinement device 400 (e.g., y and z directions). In various embodiments, control signals and / or voltages are applied to control electrodes 416 to generate desired potential fields within confinement region 100. For example, in various embodiments, a time-dependent, time-varying, time-evolving, and / or non-static direct current (DC) voltage may be applied to control electrode 416 to generate time-dependent, time-varying, time-evolving, and / or non-static potential fields that cause quantum objects trapped within confinement device 400 to traverse corresponding trajectories into confinement region 100. For example, quantum objects may be moved between various zones of confinement device 400 so that various functions may be performed on the quantum objects. For example, quantum objects may be initialized, gated by a one-qubit gate, gated by a two / multi-qubit gate, transported and / or stored, read and / or detected, etc. In exemplary embodiments, control electrode 416 is configured to generate a pushing field and / or an oscillatory potential configured to cause quantum objects experiencing the pushing field and / or oscillatory potential to experience oscillations and / or small reciprocating motions in response to a control signal applied to control electrode 416. In various embodiments, pushing field 130 is configured to push quantum objects away from RF null axis 105 of confinement device 400 (which, in the exemplary embodiment, is co-located with longitudinal axis 405 of confinement region 100). A quantum object displaced from the RF null axis 105 experiences a potential (e.g., generated at least in part by application of an RF signal to the RF electrodes 412) that causes the quantum object to vibrate and / or experience a small reciprocating motion at the quantum object's position along the RF null axis 105 / longitudinal axis 405 of the confinement device 400 in a direction transverse to (e.g., perpendicular in an exemplary embodiment) the RF null axis 105.For example, pushing a quantum object radially (e.g., in the yz-plane) away from RF null axis 105 causes the quantum object to experience a potential that causes the quantum object to vibrate and / or experience a small reciprocating motion in a radial direction of the confinement region (e.g., in the y-direction when the quantum object is pushed away from RF null axis 105 in the y-direction as shown in FIG. 2). In various embodiments, the oscillating potential is configured to vibrate and / or cause the quantum object experiencing the oscillating potential to experience a small reciprocating motion in a direction substantially parallel to RF null axis 105 / longitudinal axis 405 of confinement device 400. For example, experiencing the oscillating potential causes the quantum object to vibrate and / or experience a small reciprocating motion in a longitudinal direction of confinement region 100 (e.g., in the x-direction as shown in FIG. 3).

[0037] In various embodiments, the control signals and / or voltages applied to the control electrodes 416 are controlled by one or more connected devices (e.g., controller 30 shown in FIG. 6, etc.) via leads. For example, depending on the strength (e.g., charge in the case of an electric monopole) of the quantum object's electric monopole and / or dipole (or pole of larger magnitude), a longitudinal voltage may be increased or decreased for the control electrodes 416 in the vicinity of a particular quantum object to cause the particular quantum object to traverse a desired trajectory. For example, the controller 30 may control the voltage drivers to apply control signals and / or longitudinal voltages to the control electrodes to generate time-dependent potentials (e.g., potentials that develop, vary, and / or change over time) that cause the quantum objects in the confinement device 400 to traverse a desired trajectory. In various embodiments, the controller 30 may control the voltage driver (or other signal generator) to generate an electric potential that causes the second species quantum object 110B to vibrate or experience a small reciprocating motion transverse to the RF null axis 105.

[0038] Depending on factors such as the strength (e.g., charge in the case of an electric monopole) of the quantum object's electric monopole and / or dipole (or pole of larger magnitude) and / or the shape and / or magnitude of the combined electric and / or magnetic fields, the quantum object may be stabilized at a specific distance (e.g., about 20 μm to about 200 μm) above the top surface of confinement device 400 (e.g., the coplanar top surface of sequence of control electrodes 414 and RF electrodes 412). To further contribute to controlling the passage of quantum objects along desired trajectories, in various embodiments, confinement device 400 may be operated in a cryogenic and / or vacuum chamber capable of cooling confinement device 400 to a temperature below 124 Kelvin (e.g., below 100 Kelvin, below 50 Kelvin, below 10 Kelvin, below 5 Kelvin, etc.).

[0039] In various embodiments, RF electrode 412, sequence of control electrodes 414, and / or the confinement potential generated by RF electrode and / or sequence of control electrodes 414 define confinement region 100 of confinement device 400. In exemplary embodiments, RF electrode 412 and / or the confinement potential generated by RF electrodes 412 and / or the confinement potential generated by RF electrodes 416 define confinement region 100 of confinement device 400, and control electrode 416 controls the movement and / or positioning of quantum object crystal 110 within confinement region 100. In various embodiments, RF electrode 412, sequence of control electrodes 414, and / or the confinement potential generated by RF electrode and / or sequence of control electrodes 414 define axis 405 of confinement device 400. For example, RF electrode 412 and / or the confinement potential generated by RF electrodes may define axis 405 of confinement device 400. In various embodiments, the confinement potential generally acts to align the crystals 110 of quantum objects within the confinement device 400 along the RF null axis 105 and / or the longitudinal axis 405 of the confinement device 400 .

[0040] Exemplary quantum object detection functions In various embodiments, controller 30 may control one or more drivers to cause multiple potential-generating elements of the confinement device (e.g., RF electrode 412 and control electrode 416) to generate a time-dependent potential field (e.g., a potential field that evolves over time) that confines quantum object crystal 110 within confinement region 100 of confinement device 400. Exemplary quantum computer 610 and controller 30 are described in more detail elsewhere herein in connection with FIGS. 6 and 7. Controller 30 may control one or more drivers (e.g., voltage source 50), manipulation sources 60 (e.g., lasers), etc. to perform quantum circuits using quantum object crystal 110 within confinement device 400. A quantum circuit is a computational routine that includes coherent quantum operations on quantum data such as qubits (e.g., first-type quantum objects in quantum object crystal 110). For example, a quantum circuit includes an ordered sequence of quantum gates. Execution and / or performance of a quantum circuit by a quantum computer causes the quantum computer to execute a corresponding algorithm. For example, to execute an algorithm and / or calculation, the quantum computer may perform and / or execute a quantum circuit that includes first initializing one or more qubits (e.g., a first species of quantum object in the quantum object crystal 110) to an initial quantum state, then performing an ordered series of quantum gates and / or other operations on the one or more qubits, and finally reading and / or detecting the quantum state of at least one of the qubits to determine the outcome and / or result of executing the algorithm and / or calculation.

[0041] In exemplary embodiments, the quantum circuit may include reading and / or detecting the quantum state of at least one of the qubits midway through the quantum circuit. For example, after executing one or more gates, the quantum state of one or more of the qubits may be read and / or detected, and then one or more additional gates may be executed. In exemplary embodiments, the one or more additional gates may be determined, modified, adjusted, selected, ordered, etc. based at least in part on the results of reading and / or detecting the quantum state of the at least one qubit midway through the quantum circuit. To enable reading and / or detecting the quantum state of the at least one qubit during execution of the quantum circuit (e.g., midway through the quantum circuit), a quantum object detection function is configured to be executed before every reading and / or detection of the quantum state of the at least one qubit to accurately detect a quantum object in the ion trap without introducing qubit errors or otherwise adversely affecting the quantum state of the at least one qubit if no loss has occurred. In various embodiments, the quantum object detection function is performed periodically during the execution of the quantum circuit to determine whether to continue execution of the quantum circuit (e.g., if one or more quantum objects are lost, it may be desirable to stop execution of the quantum circuit, reload the quantum objects, and start the quantum circuit over), whether to reload one or more quantum objects into the containment device, etc. In this manner, the probability that quantum information / data stored by the qubits of the quantum object's crystals will be lost, disturbed, corrupted, etc. during the detection process is reduced. Figure 5 provides a flow diagram illustrating processes, procedures, operations, etc. performed by controller 30, for example, to control a quantum computer and / or to cause a quantum circuit, including an exemplary embodiment of the quantum object detection function, to run and / or perform.

[0042] Beginning at step / operation 502, controller 30 may control one or more voltage sources 50 to cause quantum object confinement device 400 to confine quantum object crystal 110. Quantum object confinement device 400 includes (a) one or more RF electrodes 412 that define a radio frequency (RF) null axis 105 of quantum object confinement device 400, and (b) a plurality of control electrodes 416. Quantum object crystal 110 (i) includes at least one of (a) a first-type quantum object 110A or (b) a second-type quantum object 110B, and (ii) defines a crystal axis 190 that is aligned along RF null axis 105 of quantum object confinement device 400. For example, when a quantum object is positioned on RF null axis 105, the quantum object does not experience any radial force (e.g., a force in a direction substantially perpendicular to RF null axis 105) as a result of a trapping pseudopotential generated as a result of an RF voltage applied to at least one RF electrode.

[0043] Controller 30 may execute executable instructions to perform detection of loss of quantum objects in quantum object crystal 110 via processing device 1005 of controller 30. For example, in step / operation 504, controller 30 may cause voltage source 50 to provide a first control signal to one or more control electrodes 416, as shown in FIG. 2 , that causes quantum object crystal 110 to experience pushing field 130. In various embodiments, pushing field 130 causes quantum object crystal 110 to experience a pushing field and / or an oscillating potential such that crystal axis 190 rotates relative to RF null axis 105 with a vector component transverse to RF null axis 105. When quantum objects within confinement region 100 are not positioned on RF null axis 105, the quantum objects experience an oscillating radial force as a result of the trapping pseudopotential. This oscillating radial force causes quantum objects positioned off RF null axis 105 to exhibit oscillations and / or small reciprocating motions. The oscillations in the confining potential cause both the first species quantum object 110A and the second species quantum object 110B to vibrate at the RF drive frequency and / or cause the first species quantum object 110A and the second species quantum object 110B to experience small reciprocating motions at the RF drive frequency.

[0044] When quantum object crystal 110, including first-species quantum object 110A and second-species quantum object 110B, is placed within a trap in quantum object confinement device 400, the mutual Coulomb repulsion between first-species quantum object 110A and second-species quantum object 110B causes both of the quantum objects to relocate from their original trapped positions along RF null axis 105, as shown in Figure 1. First-species quantum object 110A and second-species quantum object 110B do not experience any further motion and remain confined within the quantum object confinement device at the weakest potential. However, when the quantum object crystal is rotated so that the crystal axis 190 has a vector component transverse (e.g., substantially perpendicular) to the RF null axis 105, Coulomb repulsion 180 between the quantum objects of the quantum object crystal 110 causes the quantum objects to push each other away from the RF null axis 105 such that the quantum objects of the quantum object crystal exhibit radial (e.g., substantially perpendicular to the RF null axis 105) vibrations and / or small reciprocating motions.

[0045] In step / operation 506, controller 30 causes at least one manipulation source 60 to generate and provide detection beam 215. In various embodiments, detection beam 215 is provided that is either frequency modulated with the rf drive frequency or detuned from a particular transition by the rf drive frequency of the second species quantum object. When detection beam 215 is incident on the rotated quantum object crystal, the vibrational motion of second species quantum object 110B causes the detection beam to either frequency modulate with the rf drive frequency or detune from a particular transition by the rf drive frequency of the second species quantum object. Thus, the second species quantum object fluoresces and / or emits stimulated emission 220 in response to the detection beam 215 being incident on the second species quantum object. Detection beam 215 is off-resonance (e.g., far-resonant) from the qubit space and / or transition from the ground state of the first species quantum object. 2 shows a crystal of quantum matter 110 experiencing a pushing field 130 and having a detection beam 215 incident thereon, according to various embodiments of the present disclosure. Stimulated emission may be detected (e.g., by detector 125), and both members of the crystal of quantum matter may be determined to be present.

[0046] In step / operation 508, controller 30 may receive a signal indicative of a response of the quantum object crystal to the modulated detection beam incident on at least a portion of the quantum object crystal. For example, a signal from detector 125 may be indicative of a response of the quantum object crystal to the detection beam 215 incident on at least a portion of quantum object crystal 110. Controller 30 may then adjust, modify, update, etc., the remainder of the quantum circuit based on whether a second type quantum object is detected by detection beam 215. For example, controller 30 may make changes to the remainder of the quantum circuit in the course of performing and / or executing the quantum circuit based on and / or in response to the signal indicative of the response of the quantum object crystal to the detection beam 215 incident on at least a portion of the quantum object crystal.

[0047] In step / operation 510, controller 30 may determine whether both (a) first species quantum objects 110A and (b) second species quantum objects 110B are present in the quantum object crystal, and (c) the two species are in the expected ordering. In an exemplary embodiment, both first species quantum objects 110A and second species quantum objects 110B are present, and fluorescence may be detected by detector 125. When detector 125 detects stimulated emission 220 in response to detection beam 215 incident thereon, the signal from detector 125 may indicate that the quantum object crystal is responsive to detection beam 215 incident on at least a portion of quantum object crystal 110, and that no quantum object loss occurs in quantum object crystal 110. If it is determined that no quantum object loss occurs in the quantum object crystal, a quantum circuit using the first species quantum objects may be executed.

[0048] In an exemplary embodiment, first species quantum object 110A may be present, second species quantum object 110B may be absent, and no fluorescence may be detected by detector 125. In an exemplary embodiment, both first species quantum object 110A and second species quantum object 110B may be absent, and no fluorescence may be detected by detector 125. In an exemplary embodiment, first species quantum object 110A may be absent, second species quantum object 110B may be present, and no fluorescence may be detected by detector 125. For example, as shown in FIG. 3 , second species quantum object 110B may be present, and second species quantum object 110B may not be pushed off RF null axis 105 due to the absence of a Coulomb repulsion force from first species quantum object 110A. That is, second species quantum object 110B remains on the RF null axis even when a pushing field and / or vibrational potential 130 is generated and experienced by second species quantum object 110B. Because the detection beam 215 is modulated at a wavelength that is tuned to the fine sidebands of the second species quantum object 110B, fluorescence is suppressed by detuning the fine sidebands from the carrier transitions of the second species quantum object 110B.

[0049] When no fluorescence is detected by detector 125, the signal from detector 125 indicates that quantum object crystal 110 is not responding to modulated detection beam 215 incident on at least a portion of quantum object crystal 110. In other words, a loss or unexpected reordering of quantum objects has occurred in quantum object crystal 110. If it is determined that a loss or unexpected reordering of quantum objects has occurred in the quantum object crystal, the method may proceed to step 512, where controller 30 causes at least one manipulation source 60 to invert the modulation phase by π on detection beam 215 incident on at least a portion of the quantum object crystal.

[0050] In step / operation 514, controller 30 may receive a signal indicative of a response of the quantum object crystal to incidence of the modulated detection beam on at least a portion of the quantum object crystal. Similar to step 508, a signal from detector 125 may be indicative of a response of the quantum object crystal to incidence of modulated detection beam 215 having a modulation phase inverted by π on at least a portion of quantum object crystal 110.

[0051] In step / operation 516, controller 30 may determine whether a first species of quantum object 110A and a second species of quantum object 110B are present in a crystal of quantum object, but the two species are in an unexpected ordering.

[0052] In step / operation 518, when first species quantum objects 110A and second species quantum objects 110B are unexpectedly ordered, controller 30 may cause voltage source 50 to provide a first control signal to one or more control electrodes 416 that rotates quantum object crystal 110 an additional 180 degrees. For example, when first species quantum objects 110A and second species quantum objects 110B are unexpectedly ordered, step / operation 518 may correct the order of first species quantum objects 110A and second species quantum objects 110B.

[0053] In step / operation 522, when no unexpected ordering occurs, controller 30 may adjust the pushing field and / or vibration potential to cause all quantum objects in quantum object crystal 110 present at that location to be expelled from confinement region 110. Controller 30 may then restart the process of step / operation 502 to control one or more voltage sources 50 to cause quantum object confinement device 400 to confine a new quantum object crystal. For example, a new ion already loaded may be moved into the vacant position, or a new ion can be loaded into the vacant position and used to continue the circuit.

[0054] At step / operation 520, when controller 30 determines that no quantum object loss occurs in quantum object crystal 110, controller 30 may cause quantum computer 610 to begin executing the quantum circuit. For example, controller 30 may receive quantum circuit and / or other executable instructions (e.g., from computing entity 10 via one or more wired and / or wireless networks) that cause controller 30 to control one or more drivers such that voltage source 50, manipulation source 60, and / or other components of quantum computer 910 begin executing the quantum circuit. Controller 30 may then cause one or more gates to be performed on first species quantum object 110A (e.g., using one or more manipulation sources 60) such that the quantum state of first species quantum object 110A evolves in a particular manner within the defined qubit space of quantum object crystal 110.

[0055] In exemplary embodiments, a quantum circuit using a first species of quantum object may be executed. In exemplary embodiments, during execution of the quantum circuit, a read function to be performed on the first species of quantum object may be identified, and providing at least one first control signal to at least one control electrode and causing a manipulation source to generate and provide a read beam are performed in response to identifying the read function to be performed. In exemplary embodiments, executing the quantum circuit further includes receiving a read result in response to at least partial incidence of the read beam on the first species of quantum object, and adjusting the quantum circuit based at least in part on the read result, such that an adjusted quantum circuit is executed.

[0056] In step / operation 520, controller 30 may further control various components of quantum computer 610 to continue performing and / or executing the quantum circuit. For example, quantum computer 610 may continue performing and / or executing the quantum circuit, including executing one or more gates, moving the quantum object within containment device 400, performing additional read and / or detection functions (such as a quantum object loss detection function), etc. Controller 30 may then communicate one or more results of performing and / or executing the quantum circuit to computing entity 10 via one or more wired and / or wireless networks 20.

[0057] Technical Advantages Various embodiments provide a technical solution to the technical problem of detecting quantum objects in a confinement device without disturbing the quantum information / data stored and / or encoded by the quantum states of the quantum objects in the confinement device when no loss of the quantum objects has occurred. For example, a trapped ion quantum computer utilizes crystals of multiple species of quantum objects, with one species being data qubits used for computation and another species being used for co-cooling. If detection were performed directly on the quantum objects, qubit errors may be introduced and the quantum information encoded by the quantum states of the quantum objects may be adversely affected. Various embodiments may enable detection of quantum objects by detecting the quantum objects used for co-cooling, preserving the quantum information / data stored by the quantum objects during the detection process. Various embodiments enable detection of quantum objects to be performed in the middle of the execution and / or performance of a quantum circuit (e.g., by a quantum computer) without disturbing the quantum information / data stored by the species of quantum objects during the performance of the detection function.

[0058] Thus, various embodiments provide technical improvements in the field of quantum computer operation (e.g., for QCCD-based quantum computers, etc.), as well as in the field of detecting the presence of quantum objects within quantum object confinement devices in applications that enable the retention of quantum information / data stored by the quantum objects.

[0059] Exemplary Quantum Computer Including an Ion Trap Device As mentioned above, in various embodiments, the quantum object loss detection function is performed by the controller 30 of the quantum computer 610. Figure 6 provides a schematic diagram of an exemplary quantum computer system 600 including a containment device 400 (e.g., an ion trap), according to an example embodiment.

[0060] In various embodiments, quantum computer system 600 includes computing entity 10 and quantum computer 610. In various embodiments, quantum computer 610 includes controller 30, a cryostat and / or vacuum chamber 40 enclosing containment device 400, one or more manipulation sources 60, one or more voltage sources 50, one or more magnetic field generators 70 (e.g., 70A, 70B), an optical collection system 80, etc. In various embodiments, controller 30 is configured to control the operation of (e.g., control one or more drivers configured to cause operation of) manipulation sources 60, voltage sources 50, magnetic field generators 70, vacuum system, and / or cryogenic cooling system (not shown), etc. In various embodiments, controller 30 is configured to receive signals (e.g., electrical signals) generated and provided by optical collection system 80.

[0061] In exemplary embodiments, the one or more manipulation sources 60 may include one or more sources (e.g., optical lasers, microwave sources, etc.). In various embodiments, the one or more manipulation sources 60 are configured to manipulate and / or cause the controlled quantum state evolution of one or more quantum objects 110A / 110B within the confinement device 400. In exemplary embodiments, at least one of the one or more manipulation sources 60 is configured to generate and provide a read beam 115. For example, in exemplary embodiments in which the one or more manipulation sources 60 include one or more lasers, the lasers may provide one or more laser beams to the confinement device within the cryogenic and / or vacuum chamber 40 via beam paths 66 (e.g., 66A, 66B, 66C).

[0062] In various embodiments, quantum computer 610 includes one or more voltage sources 50. For example, the voltage sources may be arbitrary wave generators (AWGs) and / or other voltage signal generators. For example, voltage sources 50 may include multiple longitudinal voltage drivers and / or longitudinal voltage sources, and / or at least one RF driver and / or RF voltage source. Voltage sources 50 may be electrically coupled to corresponding potential-generating elements (e.g., control electrode 416 and / or RF electrode 412) of containment device 400 in exemplary embodiments.

[0063] In various embodiments, quantum computer 610 includes one or more magnetic field generators 70 (e.g., 70A, 70B). For example, magnetic field generators may be internal magnetic field generator 70A disposed within cryogenic and / or vacuum chamber 40 and / or external magnetic field generator 70B disposed outside cryogenic and / or vacuum chamber 40. In various embodiments, magnetic field generator 70 includes permanent magnets, Helmholtz coils, electromagnets, etc. In various embodiments, magnetic field generator 70 is configured to generate a magnetic field in one or more regions of quantum object confinement device 400 having a particular magnitude and a particular field direction in one or more regions of quantum object confinement device 400.

[0064] In various embodiments, quantum computer 610 includes an optical collection system 80 configured to collect and / or detect photons (e.g., stimulated emission 120) generated by a qubit (e.g., during a readout procedure). Optical collection system 80 may include one or more optical elements (e.g., lenses, mirrors, waveguides, fiber optic cables, etc.) and one or more photodetectors. In various embodiments, the photodetectors may be photodiodes, photomultiplier tubes, charge-coupled device (CCD) sensors, complementary metal-oxide semiconductor (CMOS) sensors, microelectromechanical systems (MEMS) sensors, and / or other photodetectors that are sensitive to light at the expected fluorescence wavelengths of the qubits (e.g., quantum objects) of quantum computer 610. In various embodiments, the detectors may be in electronic communication with quantum system controller 30, such as via one or more A / D converters 1025 (see FIG. 7 ).

[0065] In various embodiments, computing entity 10 is configured to allow a user (e.g., via a user interface of computing entity 10) to provide input to quantum computer 610 and receive, view, etc. output from quantum computer 610. Computing entity 10 may communicate with a controller 30 of quantum computer 610 via one or more wired or wireless networks 20 and / or via direct wired and / or wireless communication. In exemplary embodiments, computing entity 10 may convert, organize, format, etc. information / data, quantum computing algorithms (e.g., quantum circuits), etc. into a computing language, executable instructions, command set, etc. that controller 30 can understand, execute, and / or implement.

[0066] In various embodiments, controller 30 is configured to control voltage source 50, magnetic field generator 70, a cryogenic and / or vacuum system that controls the temperature and pressure within cryogenic and / or vacuum chamber 40, manipulation source 60, and / or other systems that control various environmental conditions (e.g., temperature, pressure, etc.) within cryogenic and / or vacuum chamber 40, configured to manipulate and / or cause the controlled evolution of the quantum states of one or more quantum objects within the confinement device and / or read and / or detect the quantum (e.g., qubit) states of one or more quantum objects within the confinement device. For example, controller 30 may cause the controlled evolution of the quantum states of one or more quantum objects within the confinement device to execute a quantum circuit and / or algorithm. For example, controller 30 may read and / or detect the quantum states of one or more quantum objects within the confinement device at one or more times during the execution of a quantum circuit. In various embodiments, quantum objects confined within the confinement device are used as qubits in quantum computer 610.

[0067] Exemplary Controller In various embodiments, confinement device 400 is incorporated into quantum computer 610. In various embodiments, quantum computer 610 further includes a controller 30 configured to control various elements of quantum computer 610. For example, controller 30 may be configured to control voltage source 50 configured to manipulate and / or cause the controlled evolution of the quantum states of one or more quantum objects within the confinement device and / or read and / or detect the quantum states of one or more quantum objects within the confinement device, a cryogenic and / or vacuum system that controls the temperature and pressure within cryogenic and / or vacuum chamber 40, manipulation source 60, magnetic field generator 70, and / or other systems that control environmental conditions (e.g., temperature, humidity, pressure, etc.) within cryogenic and / or vacuum chamber 40.

[0068] 7 , in various embodiments, the controller 30 may include various controller elements, including a processing device 1005, a memory 1010, a driver controller element 1015, a communication interface 1020, an analog-to-digital converter element 1025, etc. For example, the processing device 1005 may include a programmable logic device (CPLD), a microprocessor, a coprocessing entity, an application-specific instruction-set processor (ASIP), an integrated circuit, an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), a programmable logic array (PLA), a hardware accelerator, other processing devices and / or circuits, etc., and / or a controller. The term circuit may refer to an entirely hardware embodiment or a combination of hardware and a computer program product. In an exemplary embodiment, the processing device 1005 of the controller 30 includes and / or communicates with a clock.

[0069] For example, memory 1010 may include non-transitory memory such as volatile and / or non-volatile memory storage such as one or more of a hard disk, ROM, PROM, EPROM, EEPROM, flash memory, MMC, SD memory card, memory stick, CBRAM, PRAM, FeRAM, RRAM, SONOS, racetrack memory, RAM, DRAM, SRAM, FPM DRAM, EDO DRAM, SDRAM, DDR SDRAM, DDR2 SDRAM, DDR3 SDRAM, RDRAM, RIMM, DIMM, SIMM, VRAM, cache memory, register memory, etc. In various embodiments, memory 1010 may store qubit records corresponding to qubits of a quantum computer (e.g., in a qubit record data store, a qubit record database, a qubit record table, etc.), calibration tables, executable cues, computer program code (e.g., one or more computer languages, specialized controller languages, etc.), etc. In an exemplary embodiment, execution of at least a portion of the computer program code stored in memory 1010 (e.g., by processing device 1005) causes controller 30 to perform one or more steps, operations, processes, procedures, etc. described herein for controlling one or more components of quantum computer 610 (e.g., voltage source 50, manipulation source 60, magnetic field generator 70, etc.) to cause a controlled evolution of the quantum state of one or more quantum objects, detect and / or read the quantum state of one or more quantum objects, etc.

[0070] In various embodiments, the driver controller element 1015 may include one or more drivers and / or controller elements each configured to control one or more drivers. In various embodiments, the driver controller element 1015 may include a driver and / or a driver controller. For example, a driver controller may be configured to operate one or more corresponding drivers according to executable instructions, commands, etc. scheduled and executed by the controller 30 (e.g., by the processing device 1005). In various embodiments, the driver controller element 1015 may enable the controller 30 to operate the manipulation source 60. In various embodiments, the driver may be a laser driver, a vacuum component driver, a driver for controlling current and / or voltage applied to longitudinal, RF, and / or other electrodes used to maintain and / or control the confinement potential of the confinement device (and / or other driver for providing driver action sequences and / or control signals to potential-generating elements of the confinement device), a cryogenic and / or vacuum system component driver, etc. For example, the driver may control and / or include longitudinal and / or RF voltage drivers and / or voltage sources that provide voltages and / or electrical signals to the control electrode 416 and / or the RF electrode 412. In various embodiments, the controller 30 includes means for transmitting and / or receiving signals from one or more detectors 125, such as optical receiver components (e.g., cameras, MEMs cameras, CCD cameras, photodiodes, photomultiplier tubes, etc.). For example, the controller 30 may include one or more analog-to-digital converter elements 1025 configured to receive signals from one or more detectors 125, optical receiver components, calibration sensors, etc.

[0071] In various embodiments, controller 30 may include a communications interface 1020 for interfacing and / or communicating with computing entity 10. For example, controller 30 may include a communications interface 1020 for receiving executable instructions, command sets, etc. from computing entity 10, and for providing to computing entity 10 outputs received from quantum computer 610 (e.g., from a light collection system including one or more detectors 125) and / or results of processing the outputs. In various embodiments, computing entity 10 and controller 30 may communicate via a direct wired and / or wireless connection and / or one or more wired and / or wireless networks 20.

[0072] Exemplary Computing Entity 8 provides an explanatory schematic diagram depicting an exemplary computing entity 10 that may be used in conjunction with embodiments of the present invention. In various embodiments, computing entity 10 is configured to allow a user (e.g., via a user interface of computing entity 10) to provide input to quantum computer 610 and receive, display, analyze, etc. output from quantum computer 610.

[0073] 8, computing entity 10 may include an antenna 1112, a (e.g., wireless) transmitter 1104, a (e.g., wireless) receiver 1106, and a processing element 1108 that provides signals to and receives signals from transmitter 1104 and receiver 1106, respectively. The signals provided to and received from transmitter 1104 and receiver 1106, respectively, may include signaling information / data in accordance with the air interface standard of the applicable wireless system for communicating with various entities, such as controller 30, other computing entities 10, etc. In this regard, computing entity 10 may be capable of operating with one or more air interface standards, communication protocols, modulation types, and access types. For example, computing entity 10 may be configured to receive and / or provide communications using a wired data transmission protocol such as Fiber Distributed Data Interface (FDDI), Digital Subscriber Line (DSL), Ethernet, Asynchronous Transfer Mode (ATM), Frame Relay, Data over Cable Service Interface Specification (DOCSIS), or any other wired transmission protocol.Similarly, the computing entity 10 may be configured to support a variety of standards, including General Packet Radio Service (GPRS), Universal Mobile Telecommunications System (UMTS), Code Division Multiple Access 2000 (CDMA2000), CDMA2000 1X (1xRTT), Wideband Code Division Multiple Access (WCDMA), Global System for Mobile Communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), Time Division Synchronous Code Division Multiple Access (TD-SCDMA), Long Term Evolution (LTE), Evolved Universal Terrestrial Radio Access Network (E-UTRAN), Evolution-Data Optimized (EVDO), High Speed ​​Packet Access (HSPA), High Speed ​​Downlink Packet Access (HSDPA), IEEE 802.11 (Wi-Fi), Wi-Fi It may be configured to communicate over a wireless external communications network using any of a variety of protocols, such as Direct, 802.16 (WiMAX), Ultra Wide Band (UWB), Infrared (IR) protocol, Near Field Communication (NFC) protocol, Wibree, Bluetooth protocol, Wireless Universal Serial Bus (USB) protocol, and / or any other wireless protocol.Computing entity 10 may communicate using such protocols and standards, such as Border Gateway Protocol (BGP), Dynamic Host Configuration Protocol (DHCP), Domain Name System (DNS), File Transfer Protocol (FTP), Hypertext Transfer Protocol (HTTP), HTTP over TLS / SSL / Secure, Internet Message Access Protocol (IMAP), Network Time Protocol (NTP), Simple Mail Transfer Protocol (SMTP), Telnet, Transport Layer Security (TLS), Secure Sockets Layer (SSL), Internet Protocol (IP), Transmission Control Protocol (TCP), User Datagram Protocol (UDP), Datagram Congestion Control Protocol (DCCP), Stream Control Transmission Protocol (SCTP), Hypertext Markup Language (HTML), and the like.

[0074] These communication standards and protocols enable computing entity 10 to communicate with various other entities using concepts such as Unstructured Supplementary Service information / data (USSD), Short Message Service (SMS), Multimedia Messaging Service (MMS), Dual-Tone Multi-Frequency Signaling (DTMF), and / or Subscriber Identity Module Dialer (SIM Dialer), etc. Computing entity 10 may also download modifications, add-ons, and updates to its firmware, software (including, e.g., executable instructions, applications, program modules), and operating system, for example.

[0075] Computing entity 10 may also include user interface devices including one or more user input / output interfaces (e.g., a display 1116 and / or speakers / speaker drivers coupled to processing element 1108, as well as a touchscreen, keyboard, mouse, and / or microphone coupled to processing element 1108). For example, the user output interface may be configured to provide applications, browsers, user interfaces, interfaces, dashboards, screens, web pages, pages, and / or similar terms used interchangeably herein that may be executed on and / or accessed via computing entity 10 for causing a display or audible presentation of information / data and for interaction with that information / data via one or more user input interfaces. The user input interface may include any of many devices that enable computing entity 10 to receive data, such as a keypad 1118 (hard or soft), a touch display, a voice / speech or motion interface, a scanner, reader, or other input device. In embodiments that include a keypad 1118, the keypad 1118 may include (or cause the display of) conventional numeric keys (0-9) and related keys (#, *), as well as other keys used to operate computing entity 10, and may include a full set of alphabetic keys, or a set of keys that may be actuated to provide a full set of alphanumeric keys. In addition to providing input, the user input interface may be used, for example, to activate or deactivate certain features, such as a screen saver and / or sleep mode. Through such input, computing entity 10 may collect information / data, user interaction / input, etc.

[0076] Computing entity 10 may also include volatile storage or memory 1122 and / or non-volatile storage or memory 1124, which may be embedded and / or removable. For example, non-volatile memory may be ROM, PROM, EPROM, EEPROM, flash memory, MMC, SD memory card, memory stick, CBRAM, PRAM, FeRAM, RRAM, SONOS, racetrack memory, etc. Volatile memory may be RAM, DRAM, SRAM, FPM DRAM, EDO DRAM, SDRAM, DDR SDRAM, DDR2 SDRAM, DDR3 SDRAM, RDRAM, RIMM, DIMM, SIMM, VRAM, cache memory, registered memory, etc. Volatile and non-volatile storage or memory may store databases, database instances, database management system entities, data, applications, programs, program modules, scripts, source code, object code, byte code, compiled code, interpreted code, machine code, executable instructions, etc. for implementing the functionality of computing entity 10.

[0077] conclusion Many modifications and other embodiments of the inventions described herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. It is to be understood, therefore, that the inventions are not to be limited to the particular embodiments disclosed, and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms have been employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. [Explanation of symbols]

[0078] 10 Computing Entities 20 Wired and / or Wireless Networks 30 Controllers 40 Cryostat and / or vacuum chamber 50 Voltage Source 60 Operation source 66, 66A, 66B, 66C beam paths 70 Magnetic Field Generator 70A Magnetic Field Generator, Internal Magnetic Field Generator 70B Magnetic Field Generator, External Magnetic Field Generator 80 Optical Acquisition System 100 Confinement Area 105 RF null axis 110 Quantum Crystal 110A Quantum Objects of the First Kind 110B Second Kind of Quantum Objects 115 reading beam 120 Stimulated emission 125 detector 130 Pushing field, vibration potential 180 Coulomb repulsion 190 Crystal Axis 215 Detection Beam 220 Stimulated emission 400 Confinement Device 405 Longitudinal Axis 412, 412A, 412B RF electrode 414, 414A, 414B, 414C Control electrode sequence 416 Control Electrode 411, 411A, 411B Longitudinal axis 600 Quantum Computer System 610 Quantum Computer 910 Quantum Computer 1005 Processing device 1010 memory 1015 Driver Controller Element 1020 Communication Interface 1025 Analog-to-Digital Converter Elements 1104 Transmitter 1106 Receiver 1108 Processing Elements 1112 Antenna 1116 Display 1118 keypad 1122 Volatile Storage or Memory 1124 Non-volatile storage or memory

Claims

1. 1. A method performed by a controller of a quantum computer, comprising: controlling one or more voltage sources to cause a quantum object confinement device to confine a crystal of quantum objects, the quantum object confinement device including (a) one or more radio frequency (RF) electrodes defining an RF null axis of the quantum object confinement device, and (b) a plurality of control electrodes, the crystal of quantum objects (i) including at least one of (a) a first species of quantum object or (b) a second species of quantum object, and (ii) defining a crystal axis aligned along the RF null axis of the quantum object confinement device; providing at least one first control signal to at least one control electrode of the plurality of control electrodes, the at least one first control signal causing the at least one control electrode to generate a pushing field configured to rotate a crystallographic axis of the quantum object relative to the RF null axis such that the crystallographic axis has a vector component transverse to the RF null axis; causing a manipulation source to generate and provide a modulated detection beam incident on at least a portion of the crystal of the quantum object; receiving a signal indicative of a response of the quantum object crystal to the modulated detection beam incident on at least the portion of the quantum object crystal; determining, based on the signal, whether (a) the first species of quantum objects and (b) the second species of quantum objects are both present in the crystal of quantum objects, and (c) the first species of quantum objects and the second species of quantum objects are in an expected ordering; A method comprising:

2. In response to (a) the absence of the first type of quantum object or (b) the second type of quantum object, or (c) the first type of quantum object and the second type of quantum object not being in an expected ordering, the method comprises: inverting the modulation phase by π on the detection beam incident on at least a portion of the crystal of the quantum object; receiving a signal indicative of a response of the quantum object crystal to incidence of the detection beam with the modulation phase reversed on at least the portion of the quantum object crystal; determining whether the first and second types of quantum objects are unexpectedly ordered based on the signal; The method of claim 1 further comprising:

3. when the unexpected ordering is not detected by the modulated detection beam, a loss of quantum object has occurred in the quantum object crystal, the loss of quantum object comprising the first species of quantum object or the second species of quantum object disappearing from the quantum object confinement device; 3. The method of claim 2, wherein when the unexpected ordering is not detected by the modulated detection beam, the method further comprises causing at least one longitudinal electrode to generate a pushing field configured to rotate a crystal axis of the quantum object by 180 degrees.

4. In response to (a) the presence of both the first type of quantum object and (b) the second type of quantum object, and (c) the first type of quantum object and the second type of quantum object being in an expected ordering, commencing execution of a quantum circuit that uses the first type of quantum object within the quantum object confinement device; specifying a read function to be performed on the first species of quantum object during execution of the quantum circuit, wherein causing the at least one control electrode to provide the at least one first control signal and causing the manipulation source to generate and provide a read beam are performed in response to the identification of the read function to be performed; continuing execution of the quantum circuit; The method of claim 1 further comprising:

5. receiving a readout result in response to at least partial incidence of the readout beam on the first species quantum object; adjusting the quantum circuit based at least in part on the readout results such that an adjusted quantum circuit is executed; and 5. The method of claim 4, further comprising:

6. 10. The method of claim 1, wherein the first species of quantum objects are data qubits of the quantum computer and the second species of quantum objects are co-cooled ions.

7. 7. The method of claim 6, wherein the first species of quantum object is a Ba ion and the second species of quantum object is a Yb ion.

8. 10. The method of claim 1, wherein the modulated detection beam incident on at least the portion of the crystal of the quantum object has a wavelength tuned to a pulsating sideband of the second species of quantum object.

9. 1. A controller operatively connected to one or more components of a system including a quantum object confinement device, the confinement device including: (a) one or more radio frequency (RF) electrodes defining an RF null axis of the quantum object confinement device; and (b) a plurality of control electrodes, the one or more components including: (a) a voltage source; and (b) an actuation source, the controller: controlling one or more voltage sources to cause the quantum object confinement device to confine a crystal of quantum objects, the crystal of quantum objects (i) comprising at least one of (a) a first type of quantum object or (b) a second type of quantum object, and (ii) defining a crystal axis that is aligned along the RF null axis of the quantum object confinement device; providing at least one first control signal to at least one control electrode of the plurality of control electrodes, the at least one first control signal causing the at least one control electrode to generate a pushing field configured to rotate a crystallographic axis of the quantum object relative to the RF null axis such that the crystallographic axis has a vector component transverse to the RF null axis; causing a manipulation source to generate and provide a modulated detection beam incident on at least a portion of the crystal of the quantum object; receiving a signal indicative of a response of the quantum object crystal to the modulated detection beam incident on at least the portion of the quantum object crystal; determining, based on the signal, that (a) the first species of quantum objects and (b) the second species of quantum objects are both present within the crystal of quantum objects, and (c) the first species of quantum objects and the second species of quantum objects are in an expected ordering; a controller configured to:

10. in response to (a) the absence of the first type of quantum object and (b) the second type of quantum object, or (c) the first type of quantum object and the second type of quantum object not being in an expected ordering, inverting the modulation phase by π on the detection beam incident on at least a portion of the crystal of the quantum object; receiving a signal indicative of a response of the quantum object crystal to the detection beam having the inverted modulation phase incident on at least the portion of the quantum object crystal; determining whether the first type of quantum objects and the second type of quantum objects are unexpectedly ordered based on the signal; and 10. The controller of claim 9, further configured to:

11. when the unexpected ordering is not detected by the modulated detection beam, a loss of quantum object has occurred in the quantum object crystal, the loss of quantum object comprising the first species of quantum object or the second species of quantum object disappearing from the quantum object confinement device; 10. The controller of claim 9, wherein when the unexpected ordering is not detected by the modulated detection beam, the controller is further configured to cause at least one longitudinal electrode to generate a pushing field configured to rotate a crystal axis of the quantum object by 180 degrees.

12. In response to (a) the presence of both the first type of quantum object and (b) the second type of quantum object, and (c) the first type of quantum object and the second type of quantum object being in an expected ordering, commencing execution of a quantum circuit that uses the first type of quantum object within the quantum object confinement device; identifying a read function to be performed on the first species of quantum object during execution of the quantum circuit, wherein causing the at least one control signal to be provided to the at least one control electrode and causing the manipulation source to generate and provide a read beam is performed in response to identifying the read function to be performed; continuing execution of the quantum circuit; and The controller of claim 9 , further configured to:

13. receiving a readout result responsive to at least partial incidence of the readout beam on the first species quantum object; 13. The controller of claim 12, further configured to adjust the quantum circuit based at least in part on the readout results such that an adjusted quantum circuit is executed.

14. 10. The controller of claim 9, wherein the first species of quantum objects are data qubits of the quantum computer and the second species of quantum objects are co-cooled ions.

15. 15. The controller of claim 14, wherein the first species of quantum object is a Ba ion and the second species of quantum object is a Yb ion.

16. 10. The controller of claim 9, wherein the modulated detection beam incident on at least the portion of the crystal of the quantum object has a wavelength tuned to a pulsating sideband of the second species of quantum object.

17. 1. A computer program product comprising a non-transitory computer-readable medium storing executable instructions, the executable instructions, when executed by a processing device of a controller configured to control the operation of one or more components of a quantum computer, causing the controller to: controlling one or more voltage sources to cause a quantum object confinement device to confine a crystal of quantum objects, the quantum object confinement device including (a) one or more radio frequency (RF) electrodes that define an RF null axis of the quantum object confinement device, and (b) a plurality of control electrodes, the crystal of quantum objects (i) including at least one of (a) a first type of quantum object or (b) a second type of quantum object, and (ii) defining a crystal axis that is aligned along the RF null axis of the quantum object confinement device; providing at least one first control signal to at least one control electrode of the plurality of control electrodes, the at least one first control signal causing the at least one control electrode to generate a pushing field configured to rotate a crystallographic axis of the quantum object relative to the RF null axis such that the crystallographic axis has a vector component transverse to the RF null axis; causing a manipulation source to generate and provide a modulated detection beam incident on at least a portion of the crystal of the quantum object; receiving a signal indicative of a response of the quantum object crystal to the modulated detection beam incident on at least the portion of the quantum object crystal; determining, based on the signal, whether (a) the first species of quantum objects and (b) the second species of quantum objects are both present within the crystal of quantum objects, and (c) the first species of quantum objects and the second species of quantum objects are in an expected ordering; A computer program product configured to cause

18. The controller: in response to (a) the absence of said first type of quantum object or (b) the absence of said second type of quantum object, or (c) the first type of quantum object and said second type of quantum object not being in an expected ordering, inverting the modulation phase by π on the detection beam incident on at least a portion of the crystal of the quantum object; receiving a signal indicative of a response of the quantum object crystal to the detection beam having the inverted modulation phase incident on at least the portion of the quantum object crystal; determining whether the first type of quantum objects and the second type of quantum objects are unexpectedly ordered based on the signal; and 20. The computer program product of claim 17, further configured to:

19. when the unexpected ordering is not detected by the modulated detection beam, a loss of quantum object has occurred in the quantum object crystal, the loss of quantum object comprising the first species of quantum object or the second species of quantum object disappearing from the quantum object confinement device; 18. The computer program product of claim 17, wherein when the unexpected ordering is not detected by the modulated detection beam, the controller is further configured to cause at least one longitudinal electrode to generate a pushing field configured to rotate a crystallographic axis of the quantum object by 180 degrees.

20. The controller: In response to (a) the presence of both the first type of quantum object and (b) the second type of quantum object, and (c) the first type of quantum object and the second type of quantum object being in an expected ordering, commencing execution of a quantum circuit that uses the first type of quantum object within the quantum object confinement device; identifying a read function to be performed on the first species of quantum object during execution of the quantum circuit, wherein causing the at least one control signal to be provided to the at least one control electrode and causing the manipulation source to generate and provide a read beam is performed in response to identifying the read function to be performed; continuing execution of the quantum circuit; and 20. The computer program product of claim 17, further configured to:

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