Suppressing / converting leakage errors in hyperfine qubits

Abstract

The present invention is entitled Suppressing / Transforming Leakage Errors in Hyperfine Qubits. The present invention discloses a quantum computer, which includes: a device having an atomic object therein; a first manipulation source, the first manipulation source being configured to provide a first manipulation signal; a second manipulation source, the second manipulation source being configured to provide a second manipulation signal; and a controller. The controller is configured to cause the first manipulation source to provide the first manipulation signal to a region of the device; and to cause the second manipulation source to provide the second manipulation signal to the region. The first manipulation signal is tuned to excite the atomic object in the region from a leakage state outside the qubit space to an intermediate manifold, and to suppress the excitation of the atomic object in the qubit space. The second manipulation signal is tuned to excite the atomic object from the intermediate manifold to a decay manifold, and there is a non-zero probability that the atomic object will decay from the decay manifold into the qubit space.

Description

Technical Field

[0001] Various embodiments are directed to suppressing / converting leakage errors in trapped atomic object quantum computers. For example, various embodiments are directed to suppressing / converting leakage errors in hyperfine qubits. Background Art

[0002] In a trapped atomic object quantum computer, trapped atomic objects (e.g., atoms, ions, etc.) are used as qubits for the quantum computer. Similar to a classical bit, a qubit can be in one of two states (e.g., 0 or 1). However, an atomic object within a trap can be in more than two states. When an atomic object leaves the defined two-state qubit space, the atomic object is considered to have leaked. This leakage results in leakage errors. Through effort, ingenuity, and innovation, development solutions constructed in accordance with embodiments of the present invention have solved many of the deficiencies of such systems, and many examples of these solutions are described in detail herein. Summary of the invention

[0003] Exemplary embodiments provide quantum computers, systems, devices, etc. and corresponding methods for performing leakage suppression / transformation operations. In various embodiments, leakage suppression / transformation operations can be performed to reduce leakage errors experienced by a quantum computer.

[0004] According to one aspect, a quantum computer is provided. In an exemplary embodiment, the quantum computer includes: a device having one or more atomic objects therein; a first manipulation source configured to provide a first manipulation signal; a second manipulation source configured to provide a second manipulation signal; and a controller. The controller is configured to cause the first manipulation source to provide the first manipulation signal to a specific region of the device; and to cause the second manipulation source to provide the second manipulation signal to the specific region of the device. The first manipulation signal is tuned to excite the atomic objects in the specific region of the device that have leaked from the qubit space from the leakage state to the intermediate manifold, and to suppress the excitation of the atomic objects in the qubit space in the specific region of the device. The second manipulation signal is tuned to excite the atomic objects from the intermediate manifold to the decay manifold.

[0005] In an exemplary embodiment, the qubit space is defined based on a hyperfine splitting of a ground state manifold of the one or more atomic objects. In an exemplary embodiment, a controller is configured to cause the first manipulation source to provide the first manipulation signal multiple times in succession, and to cause the second manipulation source to provide the second manipulation signal multiple times in succession. In an exemplary embodiment, after the second manipulation source provides the second manipulation signal, the controller causes the first manipulation source to provide the first manipulation signal after a decay time. In an exemplary embodiment, the decay time is determined based on an average time for atomic objects to decay from the decay manifold to a ground state manifold, and the qubit space is defined within the ground state manifold. In an exemplary embodiment, (a) the one or more atomic objects have a spin 1 / 2 nucleus, and (b) the intermediate manifold is 2 D 3 / 2 manifold, and (c) the decay manifold is 2 P 1 / 2 Manifold or 3 [3 / 2] 1 / 2 manifold. In an exemplary embodiment, the first manipulation signal is tuned to excite a quadrupolar transition from the leakage state to the intermediate manifold. In an exemplary embodiment, the wave vector and polarization of the first manipulation signal are substantially orthogonal to the magnetic field in the particular region of the device. In an exemplary embodiment, the first manipulation signal is shaped to suppress transitions outside the qubit space. In an exemplary embodiment, the first manipulation signal is shaped as a hyperbolic secant shaped pulse. In an exemplary embodiment, the pulse time of the first manipulation signal is in the range of about 0.8 μs to 30 μs.

[0006] According to another aspect, a method for performing leakage suppression / transformation operations to suppress / transform leakage errors in a quantum computer is provided. In an exemplary embodiment, the method includes causing a controller of the quantum computer to cause a first manipulation source to provide a first manipulation signal to a specific region of a device of the quantum computer having one or more atomic objects therein, wherein the first manipulation signal is tuned to excite the atomic objects in the specific region of the device that have leaked from the qubit space from a leakage state to an intermediate manifold, and suppress the excitation of the atomic objects in the specific region of the device in the qubit space; and causing a second manipulation source to provide a second manipulation signal to the specific region of the device by the controller, wherein the second manipulation signal is tuned to excite the atomic objects from the intermediate manifold to the decay manifold.

[0007] In an exemplary embodiment, the qubit space is defined based on the hyperfine splitting of the ground state manifold of the one or more atomic objects. In an exemplary embodiment, the controller is configured to cause the first manipulation source to provide the first manipulation signal multiple times in succession, and to cause the second manipulation source to provide the second manipulation signal multiple times in succession. In an exemplary embodiment, after the second manipulation source provides the second manipulation signal, the controller causes the first manipulation source to provide the first manipulation signal after a decay time. In an exemplary embodiment, the decay time is determined based on an average time for atomic objects to decay from the decay manifold to a ground state manifold, and the qubit space is defined within the ground state manifold. In an exemplary embodiment, (a) the one or more atomic objects have spin 1 / 2 nuclei, and (b) the intermediate manifold is 2 D 3 / 2 manifold, and (c) the decay manifold is 2 P 1 / 2 Manifold or 3 [3 / 2] 1 / 2 manifold. In an exemplary embodiment, the first manipulation signal is tuned to excite a quadrupolar transition from the leakage state to the intermediate manifold. In an exemplary embodiment, the wave vector and polarization of the first manipulation signal are substantially orthogonal to the magnetic field in the particular region of the device. In an exemplary embodiment, the first manipulation signal is shaped to suppress transitions outside the qubit space. In an exemplary embodiment, the first manipulation signal is shaped as a hyperbolic secant shaped pulse. In an exemplary embodiment, the pulse time of the first manipulation signal is in the range of about 0.8 μs to 30 μs. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Having thus generally described the invention, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and in which:

[0009] Figure 1 A block diagram of an exemplary atomic object quantum computer is provided according to an exemplary embodiment.

[0010] Figure 2 Schematic diagrams are provided showing examples of how leakage errors in atomic objects may occur according to exemplary embodiments.

[0011] Figure 3A A graph is provided showing simulation results of final leakage error as a function of total time T for performing leakage suppression / conversion operations according to an exemplary embodiment.

[0012] Figure 3B A graph is provided showing simulation results of final leakage error as a function of the number N of cycles performed during leakage suppression / conversion operations according to an exemplary embodiment.

[0013] Figure 3C A graph showing simulation results of a final leakage error as a function of a total time T for performing a leakage suppression / conversion operation when a hyperbolic secant-shaped first manipulation signal is used according to an exemplary embodiment is provided.

[0014] Figure 4 Flowcharts are provided that illustrate various processes, procedures, and / or operations of leakage suppression / conversion methods according to exemplary embodiments.

[0015] Figure 5A , Figure 5B and Figure 5C Each provides a schematic diagram of steps for performing a leakage suppression / conversion method according to an exemplary embodiment.

[0016] Figure 5D According to an exemplary embodiment, a method similar to Figure 5B and Figure 5C Schematic diagram of the decay manifold, where the decay manifold is 3 [3 / 2] 1 / 2 Manifold.

[0017] Figure 6 A schematic diagram of an exemplary controller of a quantum computer including a device having an atomic object therein is provided according to an exemplary embodiment.

[0018] Figure 7 A schematic diagram of an exemplary computing entity of a quantum computer system that may be used in accordance with exemplary embodiments is provided. DETAILED DESCRIPTION

[0019] 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 present invention are shown. In fact, the present invention can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; on the contrary, these embodiments are provided so that the present disclosure meets applicable legal requirements. Unless otherwise indicated, the term "or" (also represented as " / ") is used herein in both alternative and combined senses. The terms "illustrative" and "exemplary" are used for examples without indication of quality level. Unless otherwise indicated, the terms "substantially" and "approximately" refer to within engineering and / or manufacturing limits and / or within the user's measurement capabilities. Throughout the content, similar reference numerals refer to similar elements.

[0020] A qubit is a quantum bit, the counterpart of the binary digit or bit of classical computing in quantum computing. Just as a bit is the basic unit of information in a classical computer, a qubit is the basic unit of information in a quantum computer. A qubit is a two-state (or two-level) quantum mechanical system, one of the simplest quantum systems that exhibits the properties of quantum mechanics. Examples of two-state quantum mechanical systems that have been used as qubits include the spin of an electron or atomic nucleus, where the two levels can be viewed as spin up and spin down, and the polarization of a single photon, where the two states can be viewed as vertical polarization and horizontal polarization.

[0021] In various embodiments, hyperfine splitting is the splitting of the energy levels of an atomic object due to the interaction between the state of the nucleus and the state of the electron cloud of the atomic object. In various embodiments, the atomic object can be an atom or an ion. In an exemplary embodiment, the atomic object is one or more atoms or ions of one or more elements and / or substances. As used herein, the term manifold refers to a plurality of states corresponding to a particular principal quantum number and angular momentum quantum number.

[0022] In various quantum mechanical systems, a two-state qubit space can be defined. For example, a two-state qubit space can be defined as two hyperfine levels of an atomic object. For example, in an atomic object with a spin 1 / 2 nucleus (such as 111Cd+, 133Ba+, 171Yb+, 199Hg+, etc.), two hyperfine levels can be defined as a two-state qubit space 215, such as Figure 2 For example, the two states may correspond to F = 0, 2 S 1 / 2 Whether the state (e.g., |0> state) is occupied or F=1, m=0, 2 S 1 / 2 state (e.g., |1> state) is occupied, where F indicates the total angular momentum of the atomic object (e.g., F is the sum of the nuclear spin and electronic angular momentum of the atomic object). However, m=0, 2 S 1 / 2 Status is not base level 2 S 1 / 2 manifold. Therefore, it is possible that atomic objects can leak from qubit space 215. For example, instead of being in F=0, 2 S 1 / 2 state (e.g., |0> state) or F=1, m=0, 2 S 1 / 2 state (e.g., |1> state), the atomic object can be in F=1, m=-1 or 1, 2 S 1 / 2state. As used herein, the quantum number m refers to, for example, the z component of the total angular momentum. Various embodiments provide techniques and corresponding devices and / or systems for suppressing / converting leakage errors caused by these leaky atomic objects. For example, various embodiments provide techniques and corresponding devices and / or systems for returning these leaky atomic objects to the qubit space 215. In various embodiments, the leakage error is converted into a standard quantum computing error (e.g., the accumulation of unwanted Stark shifts, etc.). These standard errors can be corrected and / or adjusted via quantum error correction, etc. For example, the standard error of not moving the qubit outside the qubit space can be corrected by using a quantum error correction code, and the total error level of the quantum computer can be reduced. Therefore, by reducing leakage errors and / or transforming the leakage errors experienced by the calculations performed by the quantum computer to reduce the total error rate of the quantum computer, various embodiments provide improvements to quantum computing technology, especially quantum computing technology using hyperfine qubits and / or using nuclear spin 1 / 2 atomic objects as qubits.

[0023] Exemplary quantum computer systems

[0024] Figure 1A block diagram of an exemplary quantum computer system 100 is provided. In various embodiments, the quantum computer system 100 includes a computing entity 10 and a quantum computer 110. In various embodiments, the quantum computer 110 includes a controller 30, a cryogenic chamber and / or a vacuum chamber 40 enclosing a device 50 having an atomic object therein, and one or more manipulation sources 64 (e.g., 64A, 64B, 64C). In an exemplary embodiment, the one or more manipulation sources 64 may include one or more lasers (e.g., optical lasers, microwave sources, and / or microwave masers, etc.) or another manipulation source. In various embodiments, the one or more manipulation sources 64 are configured to manipulate and / or cause controlled quantum state evolution of one or more atomic objects within the device 50. In an exemplary embodiment, the atomic object is one or more atoms or ions of one or more elements and / or substances. In an exemplary embodiment, the device 50 is an atomic object trap, an ion trap, and / or other devices configured to confine, contain, capture, and / or otherwise have atomic objects therein. For example, in an exemplary embodiment, the device 50 may be a surface ion trap. In an exemplary embodiment, where the one or more manipulation sources 64 include one or more lasers, the lasers can provide one or more laser beams to the device 50 within the cryogenic chamber and / or vacuum chamber 40. In various embodiments, the manipulation sources 64 can be used to perform door operations, cooling operations, leakage suppression / conversion operations, etc. In an exemplary embodiment, the one or more manipulation sources 64 each provide a laser beam, etc. to the device 50 via a corresponding beam path 66 (e.g., 66A, 66B, 66C). In various embodiments, at least one beam path 66 includes a modulator configured to adjust the manipulation beam provided to the device 50 via the beam path 66. In various embodiments, the manipulation sources 64, modulators, and / or other components of the quantum computer 110 are controlled by the controller 30.

[0025] In various embodiments, the computing entity 10 is configured to allow a user to provide input to the quantum computer 110 (e.g., via a user interface of the computing entity 10) and to receive, view, etc. output from the quantum computer 110. The computing entity 10 may communicate with a controller 30 of the quantum computer 110 via one or more wired or wireless networks 20 and / or via direct wired and / or wireless communications. In an exemplary embodiment, the computing entity 10 may convert, configure, format, etc. information / data, quantum computing algorithms, etc. into a computing language, executable instructions, command sets, etc. that the controller 30 may understand and / or implement.

[0026] In various embodiments, the controller 30 is configured to control: an electrical signal source and / or driver that controls the transmission of the device 50 and / or atomic objects within the device 50, a cryogenic system and / or a vacuum system that controls the temperature and pressure within the cryogenic chamber and / or vacuum chamber 40, a manipulation source 60, and / or other systems that control environmental conditions (e.g., temperature, humidity, pressure, etc.) within the cryogenic chamber and / or vacuum chamber 40 and / or configured to manipulate and / or cause a controlled evolution of the quantum state of one or more atomic objects within the device 50. In various embodiments, the atomic objects trapped within the device 50 are used as qubits of the quantum computer 110.

[0027] Overview of Leakage Suppression / Transformation Operation

[0028] In various embodiments, the atomic objects contained, trapped, and / or otherwise within the device 50 have spin 1 / 2 nuclear objects. For example, the atomic objects may be 111Cd+, 133Ba+, 171Yb+, 199Hg+, and / or other nuclear spin 1 / 2 atomic objects and / or other atomic objects that exhibit states suitable for defining a qubit space. Figure 2 S of an exemplary nuclear spin 1 / 2 atomic object including hyperfine structure is provided 1 / 2 Manifold 210 and P 1 / 2 Schematic diagram of manifold 230. Qubit space 215 includes the ground state or S 1 / 2 The m=0 state of manifold 210 is first order insensitive to small magnetic fields, which naturally gives the state a relatively long coherence time. In various embodiments, single-qubit operations and / or two-qubit operations can be performed using stimulated Raman transitions 202 that couple the two qubit states to one or more intermediate states 230 to perform the operation (e.g., possibly via virtual state 220). For example, single-qubit operations and / or two-qubit operations can be performed using stimulated Raman transitions 202 that couple the two qubit states to one or more intermediate states 230 to perform the operation (e.g., possibly via virtual state 220). 1 / 2 and P 3 / 2 state-mediated two-photon transitions to couple two states in qubit space 215. One source of error in these manipulations is due to the finite lifetime of excited states, which can lead to spontaneous emission events 204, such as Figure 2 For example, a spontaneous emission event 204 is an event in which an atomic object is de-excited from an excited state without applying an external excitation signal (e.g., a manipulation signal, etc.). These spontaneous emission events 204 can cause quantum information to leak out of the qubit space 215. For example, each spontaneous emission event 204 shown has an equal probability of occurring. Therefore, on average, one of every three spontaneous emission events will result in the atomic object being in F=1, m=-1 or 1, 2 S 1 / 2For example, one in every three spontaneous emission events 204 causes the atomic object to leak out of qubit space 215.

[0029] Various embodiments provide leakage suppression / transformation operations that use a re-pumping scheme to suppress leakage errors and return leaked atomic objects to the qubit space 215. For example, the leakage suppression / transformation operation can transform the leakage error into a standard quantum computing error that can be resolved, for example, via quantum error correction. In various embodiments, a re-pumping scheme can be used to return the leaked atomic objects to the qubit space 215. For example, the controller 30 can cause the first manipulation source 64A to provide a first manipulation beam, pulse, and / or pulse group (e.g., a laser beam, pulse, and / or pulse group; referred to herein as a first manipulation signal) that is incident on one or more atomic objects within the device 50 and addresses any leaking atomic objects. In an exemplary embodiment, the first manipulation source 64A is a laser. The first manipulation signal can be configured to address a leaking atomic object (e.g., a leaking state of F=1, m=-1 or 1, 2 S 1 / 2 state) without addressing atomic objects in the qubit space (e.g., in the state of F = 0 or 1, m = 0, 2 S 1 / 2 For example, the first manipulation signal can be configured to stimulate a quadrupolar transition from a leakage state. For example, the first manipulation signal can be tuned to be coupled to a transition from a leakage state (e.g., F=1, m=-1 or 1, 2 S 1 / 2 states) to intermediate manifold 240. In various embodiments, for transitions originating from within qubit space 215 (e.g., F=0 or 1, m=0, 2 S 1 / 2 In some embodiments, the first manipulation signal may be tuned to be non-resonant. For example, a leaky atomic object may transition from a leaky state to a state of intermediate manifold 240 via the first manipulation signal (e.g., possibly using a quadrupole transition), and the atomic objects within the qubit space may generally be unaffected (and / or minimally affected) by the first manipulation signal.

[0030] For example, the controller 30 may cause the second manipulation source 64B to provide a second manipulation beam, pulse, and / or pulse group (e.g., a laser beam, pulse, and / or pulse group; referred to herein as a second manipulation signal) that is incident on one or more atomic objects within the device 50 and addresses the atomic objects in the intermediate state. In an exemplary embodiment, the second manipulation source 64B is a laser. In various embodiments, the second manipulation signal may cause the atomic objects in the intermediate manifold 240 to transition to one or more states in the decay manifold 230. In various embodiments, the decay manifold 230 is a state in which the state rapidly decays to S 1 / 2 A manifold in which a significant percentage of atomic objects decay from one or more states in the decay manifold 230 to the ground state and / or S 1 / 2 manifold 210, and thus expected to decay into qubit space 215. For example, there is a non-zero probability that an atomic object will decay from decay manifold 230 into qubit space 215. In various embodiments, a significant percentage may be a percentage of at least about 15%, 20%, 25%, 30%, 33%, 40%, 50%, 66%, etc. In various embodiments, atomic objects in decay manifold 230 may be allowed to spontaneously decay to the ground state and / or S 1 / 2 Manifold 210.

[0031] In various embodiments, the process of applying a first manipulation beam, pulse, and / or multiple pulses (e.g., a first manipulation signal) to cause the leaked atomic objects to transition to the intermediate manifold 240 and applying a second manipulation beam, pulse, and / or multiple pulses (e.g., a second manipulation signal) to cause the atomic objects in the intermediate manifold 240 to transition to the decay manifold 230 can be repeated for multiple cycles. For example, the process can be repeated for N cycles. In an exemplary embodiment, the number of cycles N is a set number of cycles. For example, the number of cycles N can be configured to reduce the leakage population (e.g., the population of leaked atomic objects) by a threshold factor, a threshold percentage, etc. In various embodiments, the leakage population is reduced by returning the leaked atomic objects to the qubit space 215. In various embodiments, the threshold factor, threshold percentage, etc. are selected based on time constraints, computational fidelity constraints, etc.

[0032] In the exemplary embodiment, the intermediate manifold 240 is D 3 / 2 In an exemplary embodiment, the first manipulation signal may be configured to use the 1 / 2 Manifold to D 3 / 2 Specifically, the first manipulation signal of the pulse can be configured to be a quadrupole transition of the leaking atomic object (for example, at F = 1, m = -1 or 1, 2 S 1 / 2 state) without addressing atomic objects in the qubit space (e.g., in the state of F = 0 or 1, m = 0,2 S 1 / 2 For example, the first manipulation signal can be tuned to be the same as S 1 / 2 |F=1> to D 3 / 2 |F=1> transition resonance. However, S 1 / 2 Manifolds and D 3 / 2 The hyperfine splitting in the manifold renders the other transitions non-resonant. For example, the first manipulation signal can be tuned to excite the transition S 1 / 2 |F=1,m=-1>to D 3 / 2 |F=1,m=1>and S 1 / 2 |F=1,m=1>to D 3 / 2 |F=1,m=-1>, without stimulating 1 / 2 |F=1,m=0>or S 1 / 2 |F=0,m=0>to D 3 / 2 In various embodiments, the attenuation manifold 230 is P 1 / 2 Manifold and / or 3 [3 / 2] 1 / 2 state and / or manifold.

[0033] In various embodiments, the first manipulation signal is configured to drive |Δm|=2 transitions and suppress |Δm|=0 or 1 transitions. For example, the wave vector (e.g., k-vector or propagation direction) of the first manipulation signal and the polarization (e.g., electrical oscillation) of the first manipulation signal (e.g., when the first manipulation signal interacts with the atomic object) can be set to be orthogonal to the magnetic field at the location where the first manipulation signal interacts with the atomic object. For example, in an exemplary embodiment, the wave vector of the first manipulation signal is along a first direction, the polarization of the first manipulation signal is along a second direction, and the magnetic field at the location of the atomic object is along a third direction. The first manipulation signal can be configured so that both the first direction and the second direction are perpendicular to the third direction. Therefore, the first manipulation signal can be used to pump leaked atomic objects to the intermediate manifold 240 without causing the atomic objects in the qubit space 215 to be pumped out of the qubit space 215.

[0034] In various embodiments, the probability that an atomic object that has been addressed by the leakage suppression / transformation cycle (e.g., pumped into intermediate manifold 240, then pumped into decay manifold 230, and then decayed into ground state manifold 210) returns to qubit space 215 is probability p q In various embodiments, π light (eg, the second manipulation signal is linearly polarized parallel to the magnetic field) is used to generate a signal from the intermediate manifold 240 (eg, D 3 / 2 manifold) to be re-pumped to the decay manifold 230 (e.g., P 1 / 2 manifold) leads to p q= 2 / 3. In various embodiments, σ ​​light (eg, the second manipulation signal is circularly polarized or linearly polarized orthogonal to the magnetic field) is used to generate a second signal from the intermediate manifold 240 (eg, D 3 / 2 manifold) to be re-pumped to the decay manifold 230 (e.g., P 1 / 2 manifold) leads to p q = 1 / 3. In various embodiments, using power broadening and isotropic polarization for the second manipulation signal results in p q ≈1 / 2.

[0035] Assuming that the first manipulation signal and the second manipulation signal are executed with unit fidelity, the leakage population (eg, the population of leaked atomic objects) will be suppressed (1-p q ) N , where N is the number of cycles. Therefore, in various embodiments, the number of cycles N is set to The leakage population is suppressed by a factor η. In an exemplary embodiment, η is a threshold factor that specifies a target leakage suppression.

[0036] As described above, the first manipulation signal is configured to drive the |Δm|=2 transition and suppress the |Δm|=0 and 1 transitions. One possible source of error in this re-pumping scheme is the interaction of atomic objects within qubit space 215 with D 3 / 2 , F = 2 manifold non-resonant coupling. For example, an atomic object in qubit space 215 can be transferred to D via interaction with the first manipulation signal 3 / 2 ,F=2,m=±2 states, which will then be re-pumped to the decay manifold 230 with probability p r into a leakage error. The probability of this happening in a single cycle will be approximately equal to p r (Ω (1,0),(2,2) / Δ hf ) 2 , where Ω (1,0),(2,2) YesS 1 / 2 ,F=1, F = 2, m = the resonant Rabi frequency of the ±2 transition, and Δ- hf is equal to D 3 / 2 Since this leakage error is also suppressed during subsequent cycles, the total leakage error from this process will be The target leakage error should be kept below Based on the quadrupole Rabi frequency Ω and using Ωτ π =π to define the pulse time τ π The following approximate upper limit on the first pulse time is given to keep the target leakage error below The first pulse time is the time length of the pulse of the first manipulation signal.

[0037] Another source of error arises from the imperfect alignment between the magnetic field and the polarization and wave vector of the first manipulation signal. This imposes another constraint on the first pulse timing, where β is the suppression factor by which the Rabi frequency is suppressed due to the imperfect alignment between the magnetic field and the polarization and wave vector of the first manipulation signal, and Δ z is the Zeeman energy splitting in the manifold of interest. For small angular errors, the suppression factor is where γ is the angle between the magnetic field and the polarization. Putting the two constraints on the time of the first pulse together can be written as

[0038]

[0039] By equating these two limits, it is possible to determine the amount of angular error that can be tolerated without sacrificing any speed. For example, 133 Ba+sum 171 D in Yb+ 3 / 2 The hyperfine splittings are 937 MHz and 860 MHz respectively, giving angular error tolerances of 26 mrad and 28 mrad assuming a nominal magnetic field (eg, B field) of 5 Gauss.

[0040] from After N cycles, the final leakage error is the sum of the suppressed initial leakage error and the leakage error caused by the non-resonant coupling or Where T = Nτ π is the total time for performing the leakage suppression / transformation operation (assuming that the re-pumping step (e.g., providing the second manipulation signal and allowing the atomic object to decay from the decay manifold 230 to S 1 / 2 or ground state manifold 210) has a negligible contribution to the total time of the entire operation).

[0041] Figure 3A Provides a graph showing the final leakage error A graph of the simulation results of the final leakage error as a function of the total time for performing the leakage suppression / conversion operation, and Figure 3B A graph showing the final leakage error as a function of the number of cycles N is provided. In this simulation, p q =p r =1 / 2, And Δ hf / 2π=860MHz. Figure 3A and Figure 3B The results shown show that at about T = 25 μs, the leakage error can be reduced from 10 -4 Suppress to 10 -7 , wherein the first pulse time is about 1 μs. In various embodiments, the total time T for performing the leakage suppression / conversion operation is less than about 50 μs. In various embodiments, the total time T for performing the leakage suppression / conversion operation is less than about 30 μs. In various embodiments, the first pulse time is in the range of about 0.5 μs to 3 μs.

[0042] The expression for the Rabi frequency is used to estimate the required laser power, for example for embodiments of leakage suppression / conversion operation. In an exemplary embodiment, with a beam waist of 15 μm, for 133 Ba+ atomic objects (e.g., ions), the first manipulation signal may have a power of at least 100 mW to achieve a first pulse time of 1 μs. In an exemplary embodiment, with a beam waist of 15 μm, for 171 For Yb+ atomic objects (eg, ions), the first manipulation signal may have a power of at least 7.4 mW to achieve a first pulse time of 1 μs.

[0043] As described above, in the simulation results, the magnetic field was taken to be 5 Gauss. However, the use of a larger magnetic field will cause further Zeeman splitting, which will increase the spectral isolation of the target transition and can alleviate the need to suppress Δm=±1 and Δm=0 transitions via selection rules, and extend the protocol to atomic objects of higher nuclear spins. In an exemplary embodiment, the magnetic field is about 5 Gauss. However, in various embodiments, the magnetic field may be greater than or less than 5 Gauss, as applicable to the application. For example, in an exemplary embodiment, a high magnetic field (e.g., a magnetic field greater than 3 Gauss or greater than 5 Gauss in various embodiments) can be used to increase detuning for unwanted transitions (e.g., transitions that excite atomic objects out of qubit space).

[0044] In various embodiments, one or more pulse shaping techniques may be used to shape the pulse of the first manipulation signal. In an exemplary embodiment, the first manipulation signal is shaped into a hyperbolic secant shaped pulse having a first pulse time, for example, in the range of about 30 μs and 0.8 μs. In various embodiments, the first manipulation signal may be shaped to reduce transitions of qubits within qubit space 215 to intermediate manifold 240 and / or to outside qubit space 215 in response to the first manipulation signal.

[0045] In various embodiments, the first manipulation source and / or the second manipulation source may cause atomic objects within qubit space 215 and / or atomic objects returned to qubit space to undergo a Stark shift. In various embodiments, controller 30 and / or computing entity 10 may apply one or more Z rotations to the qubits (e.g., physically and / or during post-processing of results generated by quantum computer 110) to compensate for the shift.

[0046] Example Operation of Leakage Suppression / Transformation Operation

[0047] Figure 4 Flowcharts are provided that illustrate processes, procedures, and / or operations, etc., performed to suppress leakage errors and return atomic objects to qubit space 215. For example, leakage errors may be transformed into standard quantum computing errors that are addressable and / or correctable. For example, standard quantum computing errors may be addressed and / or corrected via quantum error correction. In various embodiments, quantum computer 110 may include a plurality of atomic objects (e.g., trapped within device 50). Qubit space 215 may be defined using hyperfine levels of atomic objects. For example, the atomic objects may be nuclear spin 1 / 2 atomic objects, and the hyperfine structure of the ground state (e.g., 2 S 1 / 2 manifold) can be used to define the qubit space 215 (e.g., including F = 0 and 1, m = 0, 2 S 1 / 2 In various scenarios, an atomic object may leak from qubit space 215. For example, an atomic object may experience a spontaneous emission event or other excitation event and be in a leaked state (e.g., F=1, m=-1 or 1, 2 S 1 / 2 The leakage suppression / transformation operation can be used to return the atomic object from the leakage state to the qubit space 215.

[0048] Beginning at step / operation 402, a leakage suppression / transformation operation trigger is identified. In various embodiments, the trigger is the execution of a computational operation, the execution of a particular type of computational operation, a set amount of time that has passed since the last execution of a leakage suppression / transformation operation, and the like. For example, the type of computational operation may include a gate operation, a cooling operation, a transmission operation, a qubit interaction operation, a qubit measurement operation, and the like. For example, the controller 30 may schedule one or more computational operations based on a received quantum algorithm or quantum circuit (e.g., provided by the computing entity 10). Based on the scheduling of the operations identified as triggers, the controller 30 may schedule the execution of leakage suppression / transformation operations. For example, the scheduling and / or execution of gate operations in a particular region of the device 50 may be identified as a trigger based on the quantum algorithm and / or quantum circuit that the quantum computer 110 is and / or will execute. In response to identifying the scheduling and / or execution of gate operations in a particular region of the device 50, the controller 30 may schedule and / or execute leakage suppression / transformation operations to be performed in the particular region of the device 50. For example, the operation that triggers the scheduling / execution of the leakage suppression / transformation operation may address one or more atomic objects located in a specific area of ​​the device 50, and the leakage suppression / transformation operation may be configured to address one or more atomic objects located in a specific area of ​​the device 50.

[0049] In an exemplary embodiment, the computing entity 10 may provide a quantum algorithm and / or a quantum circuit. The controller 30 may receive the quantum algorithm and / or the quantum circuit and schedule and / or execute one or more operations (e.g., computational operations such as gate operations, cooling operations, transmission operations, qubit interaction operations, qubit measurement operations; leakage suppression / transformation operations; etc.). In an exemplary embodiment, the quantum algorithm and / or the quantum circuit may indicate when to perform a leakage suppression / transformation operation. In an exemplary embodiment, the controller 30 may determine when to perform a leakage suppression / transformation operation based on the computational operations of the quantum algorithm and / or the quantum circuit.

[0050] In step / operation 404, a leakage suppression / transformation operation may be initiated. For example, the controller 30 may initiate the leakage suppression / transformation operation. For example, in response to identifying a trigger, the controller 30 may schedule the execution of the leakage suppression / transformation operation and / or cause the leakage suppression / transformation operation to be performed (e.g., at a specific time and / or at a specific position in the sequence of operations performed by the quantum computer 110). When the controller 30 executes a command to cause the execution of the leakage suppression / transformation operation (e.g., at a scheduled time), the controller may cause the number of cycles n to be set to zero (e.g., set n=0), cause the first manipulation source 64A and / or the second manipulation source 64B to be turned on or preheated, access one or more parameters corresponding to the leakage suppression / transformation operation from a memory (e.g., memory 610) (e.g., first pulse time, second pulse time, first manipulation signal power, second manipulation signal power, number of cycles N, total time T of the leakage suppression / transformation operation, decay time and / or other parameters), etc.

[0051] At step / operation 406, the controller 30 causes the first manipulation source 64A to provide a first manipulation signal to a specific area of ​​the device 50. For example, the controller 30 may cause the first manipulation source 64A to provide a first manipulation signal that is incident on one or more atomic objects within the specific area of ​​the device 50 and addresses any leaking atomic objects in the specific area of ​​the device 50. In an exemplary embodiment, the first manipulation source 64A is a laser. The first manipulation signal may be configured to address leaking atomic objects (e.g., atomic objects with a leakage state of F=1, m=-1 or 1, 2 S 1 / 2 state) without addressing atomic objects in the qubit space (e.g., in the state of F = 0 or 1, m = 0, 2 S 1 / 2 For example, the first manipulation signal can be configured to stimulate a quadrupolar transition from a leakage state. For example, the first manipulation signal can be tuned to be coupled to a transition from a leakage state (e.g., F=1, m=-1 or 1, 2 S 1 / 2 state) to the intermediate manifold 240. In various embodiments, the intermediate manifold 240 is D 3 / 2 In various embodiments, for transitions originating from within qubit space 215 (e.g., F = 0 or 1, m = 0, 2 S 1 / 2 state), the first manipulation signal may be tuned to be non-resonant. For example, a leaking atomic object may transition from a leaking state to a state of intermediate manifold 240 via the first manipulation signal (e.g., possibly using a quadrupole transition), and the atomic objects within qubit space 215 may generally be unaffected (and / or minimally affected) by the first manipulation signal. For example, the first manipulation signal may be tuned to excite transition S1 / 2 |F=1,m=-1>to D 3 / 2 |F=1,m=1>and S 1 / 2 |F=1,m=1>to D 3 / 2 |F=1,m=-1>, without stimulating 1 / 2 |F=1,m=0>or S 1 / 2 |F=0,m=0〉state to D 3 / 2 Manifold transition.

[0052] In various embodiments, the wave vector of the first manipulation signal is along a first direction, the polarization of the first manipulation signal is along a second direction, and the magnetic field in a specific region of the device 50 is along a third direction. In various embodiments, the first direction and the second direction are substantially orthogonal to the third direction. For example, the wave vector and polarization of the first manipulation signal can be tailored to excite desired transitions and suppress unwanted transitions. In various embodiments, the first manipulation signal is shaped (e.g., by a pulse shaper in an optical path between the first manipulation source 64A and a specific region of the device 50) to have a shape that suppresses transitions outside of the qubit space 215. For example, the first manipulation signal can be shaped to have a hyperbolic secant shape.

[0053] In various embodiments, the first pulse time (e.g., the time length of the first manipulation signal) is in the range of about 30 μs and 0.8 μs. For example, in various embodiments, the first pulse time may be about 1 μs. In various embodiments, the first manipulation signal may be in the range of about 0.1 mW to 500 mW. For example, in an exemplary embodiment, the first manipulation signal has a beam waist of 15 μm and a power in the range of about 5 mW to 200 mW. Figure 5A A schematic diagram of applying a first manipulation signal to an atomic object in a specific area of ​​the device 50 is provided. Figure 5A As shown, in the leakage state (for example, F = 1, m = -1 or 1, 2 S 1 / 2 ) changes to the state of the intermediate manifold 240 (e.g., F = 1, m = 1 or -1, 2 D 3 / 2 ).

[0054] continue Figure 4, to step / operation 408, controller 30 causes second manipulation source 64B to provide a second manipulation signal to re-pump the leaked atomic objects from intermediate manifold 240 to attenuation manifold 230. For example, controller 30 may cause second manipulation source 64B to provide a second manipulation signal to a specific area of ​​device 50. The second manipulation signal may be tuned to excite a transition from intermediate manifold 240 to attenuation manifold 230. In various embodiments, the second manipulation signal does not resonate with a transition outside qubit space 215. In various embodiments, attenuation manifold 230 is P 1 / 2 Manifold and / or 3 [3 / 2] 1 / 2 In various embodiments, the second pulse time (eg, the time length of the second manipulation signal) is in the range of about 30 μs and 0.8 μs. For example, in various embodiments, the second pulse time may be about 1 μs.

[0055] Figure 5B A schematic diagram of applying a second manipulation signal to an atomic object in a specific region of the device 50 is provided. Figure 5B As shown, an atomic object in a state of the intermediate manifold 240 can be excited and / or transitioned to a state of the decay manifold 230, wherein the decay manifold 230 is 2 P 1 / 2 Manifold. Figure 5D A schematic diagram of a second manipulation signal is provided, which causes the atomic object to be excited and / or transition from a state of the intermediate manifold 240 to one of the states of the decay manifold 230, wherein the decay manifold is 3 [3 / 2] 1 / 2 Manifold.

[0056] continue Figure 4 , at step / operation 410, the atomic objects in the decay manifold 230 are allowed to decay into the ground state manifold 210. For example, the controller 30 waits for a decay time to allow the atomic objects in the decay manifold 230 to decay into the ground state manifold 210. In various embodiments, the decay time is predetermined based on a finite lifetime of an excited state of the decay manifold 230. Figure 5C A schematic diagram of an atomic object decaying from one of the states of the decay manifold 230 to the ground state manifold 210 is provided. Figure 5C As can be seen in FIG. 2 , when an atomic object decays from decay manifold 230 to ground state manifold 210, the atomic object will be with a certain probability (e.g., p q ) decays into qubit space 215 and will be represented by complementary possibilities (e.g., 1–p q ) decays into a leaky state. Figure 5D A schematic diagram of an atomic object decaying from one of the states of the decay manifold 230 to the ground state manifold is provided, where the decay manifold is3 [3 / 2] 1 / 2 Manifold.

[0057] In various embodiments, the controller 30 may cause a plurality of pumping cycles to be performed. In various embodiments, a cycle may include applying a first manipulation signal to a specific region of the device 50, applying a second manipulation signal to a specific region of the device 50, and waiting for a decay time to allow the atomic objects in the decay manifold 230 to decay back to the ground state manifold 210. In various embodiments, during each cycle, the atomic objects decaying from the decay manifold 230 are likely to decay into the qubit space 215 defined in the ground state manifold 210. In the next cycle, the probability that any atomic object in a leaking state will be excited by the first manipulation signal will be smaller. In this way, for each cycle, the leakage population of the atomic objects decreases. After executing the number of cycles N, a threshold factor, a threshold percentage, etc. of the leaking atomic objects return to the qubit space 215. In various embodiments, the cycle time t (e.g., the amount of time required to perform a cycle of leakage suppression / transformation operations) is the sum of the first pulse time, the second pulse time, and the decay time. For example, in an exemplary embodiment, the total time T for performing the leakage suppression / transformation operation is the product of the number of cycles N and the cycle time t (eg, which is approximately equal to the sum of the first pulse time, the second pulse time, and the decay time).

[0058] return Figure 4 , at step / operation 412, the controller 30 iterates the loop number n. For example, the controller 30 may iterate the loop number n so that n->n+1. For example, the controller 30 may use the loop number n to track the number of loops that have been executed, and the controller 30 may iterate the loop number n after executing the loop.

[0059] At step / operation 414, the controller 30 determines whether the cycle number n is equal to the cycle number N. For example, the controller 30 may be configured and / or programmed to perform a leakage operation (e.g., applying a first manipulation signal, applying a second manipulation signal, waiting for a decay time) for a cycle number N. The controller 30 may use the cycle number n to determine whether the cycle number N has been performed. In an exemplary embodiment, iterations of the cycle number n and determinations of whether the cycle number n is equal to the cycle number N may be performed while the controller 30 waits for a decay time.

[0060] When, at step / operation 414, the controller 30 determines that the loop count n is not equal to the loop quantity N (e.g., n < N), the process returns to step / operation 406 and another loop may be executed. When, at step / operation 414, the controller 30 determines that the loop count n is equal to the loop quantity (e.g., n = N), the process proceeds to step / operation 416. At step / operation 416, the controller 30 determines that the leakage suppression operation / transformation has been completed. For example, the controller 30 may update a log (e.g., stored in the memory 610) to indicate that the leakage suppression / transformation operation has been completed, execute the next command to cause the next operation to be performed, etc.

[0061] Technical advantages

[0062] In various embodiments, a two-state qubit space 215 is defined. In various embodiments, a qubit is an atomic object contained, trapped, and / or otherwise located within the device 50 of the quantum computer 110. The atomic object contained, trapped, and / or otherwise located within the device 50 may access more states than the states of the qubit space 215. For example, in FIG. 5A to FIG. 5D the illustrated embodiment shown, when the atomic object is a nuclear spin 1 / 2 atomic object, the ground state manifold 210 of the atomic object may include four states (e.g., two states in the qubit space 215 and two leakage states). Thus, when the quantum computer 110 performs various operations, one or more atomic objects trapped in the device 50 may leak into the leakage states. The leakage of the atomic object into the leakage states results in an error in the calculation performed by the quantum computer 110. By performing the leakage suppression / transformation operation, according to various embodiments, the final leakage error may be reduced by several orders of magnitude (e.g., relative to not performing the leakage suppression / transformation operation). For example, FIG. 3A to FIG. 3C it is shown that the final leakage error may be reduced to about 10 -7 where the total time T for performing the leakage suppression / transformation operation is 20 μs - 25 μs or the loop quantity N ≥ 10. Thus, the leakage suppression / transformation operation according to the exemplary embodiments provides a means for quantum error correction to improve the fidelity of the calculations performed by the quantum computer 110. For example, by returning the leaked atomic object to the qubit space 215, various embodiments enable the quantum error correction routine to more effectively improve the fidelity of the calculations performed by the quantum computer 110. Thus, various embodiments provide an improvement to the field of quantum computing by improving the operation of the quantum computer 110 that traps atomic objects.

[0063] Exemplary Controller

[0064] In various embodiments, the quantum computer 110 also includes a controller 30 configured to control various elements of the quantum computer 110. In various embodiments, the controller 30 may be configured to cause the quantum computer 110 to perform various operations (e.g., computational operations such as gate operations, cooling operations, transport operations, qubit interaction operations, qubit measurement operations; leakage suppression / transformation operations; etc.). For example, the controller 30 may be configured to identify a trigger, schedule a leakage suppression / transformation operation and / or cause a leakage suppression / transformation operation to be performed, control the first and / or second manipulation sources to provide the first and / or second manipulation signals, etc. For example, the controller 30 may be configured to control: a cryogenic system and / or a vacuum system that controls the temperature and pressure within the cryogenic chamber and / or vacuum chamber 40, the manipulation source 64, and / or control the environmental conditions (e.g., temperature, humidity, pressure, etc.) within the cryogenic chamber and / or vacuum chamber 40 and / or other systems configured to manipulate and / or cause the controlled evolution of the quantum state of one or more atomic objects within the device 50.

[0065] like Figure 6 As shown, in various embodiments, the controller 30 may include various controller elements, including a processing element 605, a memory 610, a driver controller element 615, a communication interface 620, an analog-to-digital converter element 625, etc. For example, the processing element 605 may include a programmable logic device (CPLD), a microprocessor, a co-processing 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 a complete hardware implementation or a combination of hardware and a computer program product. In an exemplary embodiment, the processing element 605 of the controller 30 includes a clock and / or communicates with a clock.

[0066] For example, memory 610 may include non-transitory memory, such as volatile and / or non-volatile memory storage devices, 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 610 may store qubit records corresponding to qubits of a quantum computer (e.g., in a qubit record data storage device, a qubit record database, a qubit record table, etc.), calibration tables, executable queues, computer program code (e.g., in one or more computer languages, a dedicated controller language, etc.), etc. In an exemplary embodiment, execution of at least a portion of the computer program code stored in memory 610 (eg, by processing element 605 ) causes controller 30 to perform one or more steps, operations, processes, procedures, etc. described herein.

[0067] In various embodiments, the driver controller element 615 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 615 may include a driver and / or a driver controller. For example, the driver controller may be configured to cause one or more corresponding drivers to operate according to executable instructions, commands, etc. scheduled and executed by the controller 30 (e.g., by the processing element 605). In various embodiments, the driver controller element 615 may enable the controller 30 to operate the manipulation source 64, operate the vacuum system and / or the cryogenic system, etc. In various embodiments, the driver may be a laser driver; a vacuum component driver; a cryogenic and / or vacuum system component driver; etc. In various embodiments, the controller 30 includes a device for transmitting signals and / or receiving signals from one or more optical receiver components (such as a camera, a MEMs camera, a CCD camera, a photodiode, a photomultiplier tube, etc.). For example, the controller 30 may include one or more analog-to-digital converter elements 625, which are configured to receive signals from one or more optical receiver components, calibration sensors, etc.

[0068] In various embodiments, the controller 30 may include a communication interface 620 for interfacing and / or communicating with the computing entity 10. For example, the controller 30 may include a communication interface 620 for receiving executable instructions, command sets, etc. from the computing entity 10, and providing the output received from the quantum computer 110 (e.g., from the light collection system) and / or the results of processing the output to the computing entity 10. In various embodiments, the computing entity 10 and the controller 30 may communicate via a direct wired and / or wireless connection and / or one or more wired and / or wireless networks 20.

[0069] Exemplary Computing Entities

[0070] Figure 7 An exemplary schematic diagram of an exemplary computing entity 10 that can be used in conjunction with embodiments of the present invention is provided. In various embodiments, the computing entity 10 is configured to allow a user to provide input to the quantum computer 110 (e.g., via a user interface of the computing entity 10) and to receive, display, analyze, etc. output from the quantum computer 110. For example, a user can operate the computing entity 10 to generate and / or program a quantum algorithm and / or quantum circuit, which can be provided so that the controller 30 can receive the quantum algorithm and / or quantum circuit and cause the quantum computer 110 to execute the quantum algorithm and / or quantum circuit.

[0071] like Figure 7As shown, the computing entity 10 may include an antenna 712, a transmitter 714 (e.g., a radio component), a receiver 706 (e.g., a radio component), and a processing element 708, which provides signals to the transmitter 714 and receives signals from the receiver 706, respectively. The signals provided to the transmitter 714 and the signals received from the receiver 706 may include signaling information / data according to the air interface standard of the applicable wireless system to communicate with various entities such as the controller 30, another computing entity 10, etc. In this regard, the computing entity 10 may be capable of operating using one or more air interface standards, communication protocols, modulation types, and access types. For example, the 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, cable service interface data specification (DOCSIS), or any other wired transmission protocol. Similarly, the computing entity 10 may be configured to communicate via a wireless external communications network using any of a variety of protocols, such as 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 Direct, 802.16 (WiMAX), Ultra Wideband (UWB), Infrared (IR) protocol, Near Field Communication (NFC) protocol, Wibree, Bluetooth protocol, wireless Universal Serial Bus (USB) protocol and / or any other wireless protocol. The computing entity 10 may use such protocols and standards to communicate using Border Gateway Protocol (BGP), Dynamic Host Configuration Protocol (DHCP), Domain Name System (DNS), File Transfer Protocol (FTP), Hypertext Transfer Protocol (HTTP), TLS / SSL / Secure HTTP, 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), etc.

[0072] Via these communication standards and protocols, computing entity 10 may communicate with various other entities using concepts such as Unstructured Supplementary Service Message / Data (USSD), Short Message Service (SMS), Multimedia Message Service (MMS), Dual Tone Multi-Frequency Signaling (DTMF), and / or Subscriber Identity Module Dial Pad (SIM Dial Pad). Computing entity 10 may also download changes, add-ons, and updates, such as to its firmware, software (e.g., including executable instructions, applications, program modules), and operating system.

[0073] The computing entity 10 may also include a user interface device including one or more user input / output interfaces (e.g., a display 716 and / or a speaker / speaker driver coupled to the processing element 708 and a touch screen, keyboard, mouse, and / or microphone coupled to the processing element 708). For example, the user output interface may be configured to provide an application, browser, user interface, interface, dashboard, screen, web page, page, and / or similar words used interchangeably herein executed on and / or accessible via the computing entity 10 to enable information / data to be displayed or audibly presented and for interacting with the application, etc. via one or more user input interfaces. The user input interface may include any of a number of devices that allow the computing entity 10 to receive data, such as a keypad 718 (hard or soft), a touch display, a sound / voice or motion interface, a scanner, a reader, or other input device. In an embodiment including a keypad 718, the keypad 718 may include (or cause to be displayed) conventional numeric keys (0-9) and related keys (#, *) and other keys for operating the computing entity 10, and may include a complete set of alphabetic keys or a set of keys that can be activated to provide a complete set of alphanumeric keys. In addition to providing input, the user input interface may also be used, for example, to activate or deactivate certain functions, such as a screen saver and / or a sleep mode. Through such input, the computing entity 10 may collect information / data, user interaction / input, etc.

[0074] The computing entity 10 may also include an embedded and / or removable volatile storage device or memory 722 and / or a non-volatile storage device or memory 724. For example, the 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. The 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, register memory, etc. The volatile and non-volatile storage devices or memories 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. to implement the functions of the computing entity 10.

[0075] in conclusion

[0076] Many modifications and other embodiments of the invention set forth herein will occur to those skilled in the art having the benefit of the foregoing description and the teachings presented in the associated drawings. Therefore, it should be understood that the invention is not limited to the particular embodiments disclosed, and modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

1. A quantum computer, comprising: a device having one or more atomic objects therein; A first manipulation source, wherein the first manipulation source is configured to provide a first manipulation signal; a second manipulation source, the second manipulation source being configured to provide a second manipulation signal; and A controller, the controller being configured to: causing the first manipulation source to provide the first manipulation signal to a specific region of the device, wherein the first manipulation signal is tuned to excite atomic objects within the specific region of the device that have leaked from qubit space from a leakage state to an intermediate manifold and to suppress excitation of atomic objects in the qubit space; and causing the second manipulation source to provide the second manipulation signal to the particular region of the device, wherein (a) the second manipulation signal is tuned to excite atomic objects from the intermediate manifold to a decay manifold, and (b) there is a non-zero probability that atomic objects will decay from the decay manifold into the qubit space.

2. The quantum computer according to claim 1, wherein the controller is configured to cause the first manipulation source and the second manipulation source to sequentially provide the first manipulation signal and the second manipulation signal multiple times to achieve a desired leakage suppression factor, wherein after the second manipulation source provides the second manipulation signal, the controller causes the first manipulation source to provide another first manipulation signal after a decay time.

3. The quantum computer of claim 2, wherein the decay time is determined based on a time for an atomic object to decay from the decay manifold to a ground state manifold, the qubit space being defined within the ground state manifold.

4. The quantum computer of claim 1 , wherein the qubit space is defined based on a hyperfine structure of a ground state manifold of the one or more atomic objects.

5. The quantum computer of claim 1 , wherein the first manipulation signal is shaped to suppress transitions out of the qubit space.

6. The quantum computer of claim 1, wherein the first manipulation signal is tuned to excite a quadrupolar transition from the leakage state to the intermediate manifold.

7. The quantum computer of claim 1 , wherein excitation of atomic objects within the qubit space is suppressed by high magnetic fields that result in large energy detuning for unwanted transitions.

8. The quantum computer of claim 1, wherein the wave vector and polarization of the first manipulation signal are arranged to minimize excitation of atomic objects out of the qubit space.

9. The quantum computer of claim 1, wherein (a) the one or more atomic objects are nuclear spin 1 / 2 atomic objects, and (b) the intermediate manifold is 2 D 3 / 2 manifold, and (c) the attenuation manifold is 2 P 1 / 2 Manifold or 3 [3 / 2] 1 / 2 One of the manifolds.

10. The quantum computer of claim 1, wherein the wave vector and polarization of the first manipulation signal are substantially orthogonal to the magnetic field in the particular region of the device.

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