Geometric phase gates using static magnetic field gradients

Abstract

The controller of the quantum system causes a geometric phase gate to be performed on two or more qubits by inducing a first adiabatic coupling of at least one memory state of the two or more quantum objects that realize two or more qubits to the respective magnetic field-sensitive states of the two or more quantum objects, while the two or more quantum objects are positioned within the static magnetic field gradient zone of the confinement device. The first adiabatic coupling is performed over the shelving time. Upon determination that the gate time period has elapsed from the completion of the shelving time, the controller causes a second adiabatic coupling of at least one memory state to the respective magnetic field-sensitive states of the two or more quantum objects, while the two or more quantum objects are positioned within the static magnetic field gradient zone.

Description

[Technical Field]

[0001] Cross-reference of related applications This application claims priority to U.S. Application No. 18 / 441,077, filed on 14 February 2024, and U.S. Application No. 63 / 487,076, filed on 27 February 2023, both of which are incorporated herein by reference in their entirety.

[0002] Various embodiments relate to quantum logic gates that use a static magnetic field gradient. Various embodiments also relate to quantum logic gates that do not use any oscillatory field to enact entanglement between quantum objects. [Background technology]

[0003] Quantum computing uses quantum interactions to perform quantum calculations. An exemplary quantum interaction is the implementation of a quantum logic gate on a pair of qubits. For example, a quantum logic gate can be used to entangle two qubits. Conventionally, the implementation of a quantum logic gate involves applying a laser beam or microwave to two qubits that are gate-controlled together to cause or mediate entanglement of the qubits. However, the use of a laser beam can result in photon scattering and / or phase noise during the implementation of conventional quantum logic gates, reducing gate fidelity. A gate of two qubits caused and / or mediated by microwaves is sensitive to motion errors and requires the qubits to be cooled to a motional ground state, which involves resistive heating that may limit its use in future architectures. Through efforts, ingenuity, and innovation, many of the shortcomings of such conventional quantum logic gates have been overcome by developing solutions constructed according to embodiments of the invention, many of which are described in detail herein. [Overview of the project] [Means for solving the problem]

[0004] Exemplary embodiments provide a method for implementing a quantum logic gate that uses a static magnetic field gradient to entangle two or more qubits, a system configured to implement such a quantum logic gate, a controller configured to cause such a quantum logic gate to be implemented in the system, and the like. In various embodiments, the quantum logic gate does not use any oscillating fields (e.g., laser beam, microwave signal, oscillating magnetic field) to cause entanglement of two or more qubits. Rather, the entanglement of two or more qubits is effected, mediated, and / or caused by a static magnetic field gradient.

[0005] In various embodiments, the step of implementing a quantum logic gate includes subjecting two or more qubits to a static magnetic field gradient. For example, two or more quantum objects may be transported into a static magnetic field gradient zone of a confinement device. In various embodiments, the two or more quantum objects are simultaneously in their respective magnetic field insensitive states (e.g., clock states) upon transport. Although the two or more quantum objects are located within the static magnetic field gradient zone, at least one magnetic field insensitive state in the memory subspace of the quantum objects is adiabatically coupled to their respective magnetic field sensitive states outside the qubit subspace of the quantum objects. For example, the adiabatic coupling may be an adiabatic Rabi flip transition, a rapid adiabatic passage (RAP) (also called an adiabatic rapid passage (ARP)), etc., in various embodiments. After adiabatic coupling is performed over a shelving time, two or more quantum objects are subjected to a static magnetic field gradient in a static magnetic field gradient zone over a gate time period. After the gate time period has elapsed, each magnetic field-sensitive state is adiabatically coupled to at least one magnetic field-insensitive state in the memory subspace of the quantum objects over a deshelving time. The two or more quantum objects can then be transported outside the static magnetic field gradient zone. Due to the first adiabatic coupling of at least one magnetic field-insensitive state in the memory subspace of the quantum objects to each magnetic field-sensitive state, the two or more quantum objects are subjected to a static magnetic field gradient. Due to the second adiabatic coupling of each magnetic field-sensitive state to at least one magnetic field-insensitive state in the memory subspace of the quantum objects, the two or more quantum objects are no longer substantially subjected to a static magnetic field gradient.

[0006] For example, in an exemplary embodiment, the step of implementing a quantum logic gate includes (a) confining at least two quantum objects, and (b) controlling the operation of a confining device to define at least one static magnetic field gradient zone for causing a first adiabatic coupling of at least one qubit state of at least two of the at least two quantum objects to respective magnetic field-sensitive states of the at least two quantum objects while the two or more quantum objects are disposed within the at least one static magnetic field gradient zone. The first adiabatic coupling is implemented over a shelving time. The step of implementing a quantum logic gate further includes controlling the operation of the confining device to cause a second adiabatic coupling of each of the at least one qubit state to a respective magnetic field-sensitive state while the two or more quantum objects are disposed within the at least one static magnetic field gradient zone in response to a determination that a gate time period has elapsed since completion of the shelving time.

[0007] According to one aspect, a method for implementing a geometric phase gate is provided. The method is implemented by a controller configured to control the operation of one or more components of a quantum system comprising a confining device configured to (a) confine at least two quantum objects and (b) define at least one static magnetic field gradient zone. In an exemplary embodiment, the method includes causing a first adiabatic coupling of at least one memory state of at least two of the at least two quantum objects to respective magnetic field-sensitive states of the at least two quantum objects while the two or more quantum objects are disposed within the at least one static magnetic field gradient zone. The first adiabatic coupling is implemented over a shelving time. The method further includes causing a second adiabatic coupling of each of the at least one memory state to a respective magnetic field-sensitive state while the two or more quantum objects are disposed within the at least one static magnetic field gradient zone in response to a determination that a gate time period has elapsed since completion of the shelving time.

[0008] In an exemplary embodiment, two or more quantum objects become entangled within a static magnetic field gradient zone during a gate time period without using any oscillatory field to perform / mediate the entanglement of the two or more quantum objects.

[0009] In an exemplary embodiment, a static magnetic field gradient facilitates / mediates the entanglement of two or more quantum objects within the static magnetic field gradient zone.

[0010] In an exemplary embodiment, the gate time period is determined at least in part on the amount of time it takes for the static magnetic field gradient to mediate / enforce / cause entanglement of two or more quantum objects.

[0011] In an exemplary embodiment, the step of causing a first adiabatic coupling is: (a) At the initial time, characterized by (i) a detuning from a transition between at least one memory state and its respective magnetic field-sensitive state, equal to the initial detuning, and (ii) an initial amplitude; (b) At the final time, characterized by (i) a detuning from a transition equal to the final detuning, which is substantially equal in magnitude and opposite sign to the initial detuning, and (ii) a final amplitude substantially equal to the initial amplitude; (c) Between the initial and final time, the step includes (i) a detuning of a smooth and flat transition from the initial detuning to the final detuning, and (ii) generating an operating signal in which the amplitude increases from the initial amplitude to the maximum amplitude, then decreases from the maximum amplitude to the final amplitude, and when the detuning from the transition is equal to zero, the amplitude is equal to the maximum amplitude.

[0012] In an exemplary embodiment, the first adiabatic bond is a rapid adiabatic passage, and the second adiabatic bond is the inverse of the first adiabatic bond.

[0013] In an exemplary embodiment, the second adiabatic coupling is performed over the deshelving time.

[0014] In exemplary embodiments, the shelving time and deshelving time are in the range of 5 to 10 microseconds (μs), respectively.

[0015] In an exemplary embodiment, at least one of the first adiabatic coupling or the second adiabatic coupling is a Rabi flop transition.

[0016] In an exemplary embodiment, the method further includes the step of transporting two or more quantum objects into at least one static magnetic field gradient zone prior to the step of inducing a first adiabatic coupling.

[0017] In an exemplary embodiment, a first potential generation signal filtering scheme is used to filter potential generation signals used to transport two or more quantum objects into at least one static magnetic field gradient zone.

[0018] In an exemplary embodiment, a second potential-generating signal filtering scheme, distinct from the first potential-generating signal filtering scheme, is used to filter the potential-generating signal used to confine two or more quantum objects within a static magnetic field gradient zone during the execution of the first adiabatic coupling, the gate time period, and the execution of the second adiabatic coupling.

[0019] In an exemplary embodiment, the method further includes the step of transporting two or more quantum objects outside at least one static magnetic field gradient zone after performing a second adiabatic coupling over a deshelving time.

[0020] In an exemplary embodiment, a first potential generation signal filtering scheme is used to filter potential generation signals used to transport two or more quantum objects outside of at least one static magnetic field gradient zone.

[0021] In an exemplary embodiment, a second potential-generating signal filtering scheme, distinct from the first potential-generating signal filtering scheme, is used to filter the potential-generating signal used to confine two or more quantum objects within a static magnetic field gradient zone during the execution of the first adiabatic coupling, the gate time period, and the execution of the second adiabatic coupling.

[0022] In exemplary embodiments, the step of inducing at least one of a first adiabatic coupling or a second adiabatic coupling includes controlling the operation of the quantum system's operating source to cause at least one operating signal to be incident on two or more quantum objects located within a static magnetic field gradient zone.

[0023] In an exemplary embodiment, at least one operating signal includes at least one of a microwave signal or a laser beam.

[0024] In another embodiment, a system configured to implement geometric phase gates is provided. In an exemplary embodiment, the system comprises a confinement device that defines (at least partially) one static magnetic field gradient zone and is operable to confine two or more quantum objects. The system further comprises a controller configured to control the operation of the confinement device. The controller is configured to control the operation of one or more components of the system to implement a first adiabatic coupling of at least one memory state of at least two of the quantum objects to the respective magnetic field-sensitive states of the two or more quantum objects, while the two or more quantum objects are located within at least one static magnetic field gradient zone. The first adiabatic coupling is implemented over a shelving time. The controller is further configured to control the operation of one or more components of the system to implement a second adiabatic coupling of at least one memory state to the respective magnetic field-sensitive states of the two or more quantum objects, while the two or more quantum objects are located within at least one static magnetic field gradient zone, in response to a determination that a gate time period has elapsed from the completion of the shelving time.

[0025] In an exemplary embodiment, two or more quantum objects become entangled within a static magnetic field gradient zone during a gate time period without using any oscillatory field to perform / mediate the entanglement of the two or more quantum objects.

[0026] In an exemplary embodiment, the static magnetic field gradient facilitates / mediates the entanglement of two or more quantum objects within the static magnetic field gradient zone.

[0027] In an exemplary embodiment, the gate time period is determined at least in part on the amount of time it takes for the static magnetic field gradient to mediate / enforce / cause entanglement of two or more quantum objects.

[0028] In exemplary embodiments, inducing a first adiabatic coupling includes (a) at an initial time point, characterized by (i) a detuning from a transition between at least one memory state and its respective magnetic field-sensitive state, equal to an initial detuning, and (ii) an initial amplitude; (b) at a final time point, characterized by (i) a detuning from a transition equal to a final detuning, which is substantially equal in magnitude and opposite sign to the initial detuning, and (ii) a final amplitude substantially equal to the initial amplitude; and (c) between the initial and final time points, inducing an operating signal, which includes (i) a detuning of a smooth and flat transition from the initial detuning to the final detuning, and (ii) an amplitude that increases from the initial amplitude to the maximum amplitude, then decreases from the maximum amplitude to the final amplitude, and when the detuning from the transition is equal to zero, the amplitude is equal to the maximum amplitude.

[0029] In an exemplary embodiment, the first adiabatic bond is a rapid adiabatic passage, and the second adiabatic bond is the inverse of the first adiabatic bond.

[0030] In an exemplary embodiment, the second adiabatic coupling is performed over the deshelving time.

[0031] In exemplary embodiments, the shelving time and deshelving time are in the range of 5 to 10 μs, respectively.

[0032] In an exemplary embodiment, at least one of the first adiabatic coupling or the second adiabatic coupling is a Rabi flop transition.

[0033] In an exemplary embodiment, the controller is further configured to control the behavior of one or more components of the system to carry out transporting two or more quantum objects into at least one static magnetic field gradient zone prior to inducing a first adiabatic coupling.

[0034] In an exemplary embodiment, a first potential generation signal filtering scheme is used to filter potential generation signals used to transport two or more quantum objects into at least one static magnetic field gradient zone.

[0035] In an exemplary embodiment, a second potential-generating signal filtering scheme, distinct from the first potential-generating signal filtering scheme, is used to filter the potential-generating signal used to confine two or more quantum objects within a static magnetic field gradient zone during the execution of the first adiabatic coupling, the gate time period, and the execution of the second adiabatic coupling.

[0036] In an exemplary embodiment, the method further includes the step of transporting two or more quantum objects outside at least one static magnetic field gradient zone after performing a second adiabatic coupling over a deshelving time.

[0037] In an exemplary embodiment, a first potential generation signal filtering scheme is used to filter potential generation signals used to transport two or more quantum objects outside of at least one static magnetic field gradient zone.

[0038] In an exemplary embodiment, a second potential-generating signal filtering scheme, distinct from the first potential-generating signal filtering scheme, is used to filter the potential-generating signal used to confine two or more quantum objects within a static magnetic field gradient zone during the execution of the first adiabatic coupling, the gate time period, and the execution of the second adiabatic coupling.

[0039] In exemplary embodiments, the step of inducing at least one of a first adiabatic coupling or a second adiabatic coupling includes controlling the operation of the quantum system's operating source to cause at least one operating signal to be incident on two or more quantum objects located within a static magnetic field gradient zone.

[0040] In an exemplary embodiment, at least one operating signal includes at least one of a microwave signal or a laser beam.

[0041] In another embodiment, a controller is provided which is configured to control one or more components of a quantum system and to cause the quantum system to perform geometric phase gates. In an exemplary embodiment, the controller comprises a processing device, a memory storing executable instructions, and a driver controller element. The executable instructions, when executed by the processing device, are configured to cause the controller to use the driver controller element to control the operation of the confinement device to perform a first adiabatic coupling of at least one memory state of at least two quantum objects to the respective field-sensitive states of the two or more quantum objects, while the two or more quantum objects are located within at least one static field gradient zone. The first adiabatic coupling is performed over a shelving time. These executable instructions, when executed by the processing device, are further configured to cause the controller to use the driver controller element to control the operation of the confinement device to perform a second adiabatic coupling of at least one memory state to the respective field-sensitive states of the two or more quantum objects, while the two or more quantum objects are located within at least one static field gradient zone, in response to a determination that a gate time period has elapsed from the completion of the shelving time.

[0042] In an exemplary embodiment, two or more quantum objects become entangled within a static magnetic field gradient zone during a gate time period without using any oscillatory field to perform / mediate the entanglement of the two or more quantum objects.

[0043] In an exemplary embodiment, a static magnetic field gradient facilitates / mediates the entanglement of two or more quantum objects within the static magnetic field gradient zone.

[0044] In an exemplary embodiment, the gate time period is determined at least in part on the amount of time it takes for the static magnetic field gradient to mediate / enforce / cause entanglement of two or more quantum objects.

[0045] In exemplary embodiments, inducing a first adiabatic coupling includes (a) at an initial time point, characterized by (i) a detuning from a transition between at least one memory state and its respective magnetic field-sensitive state, equal to an initial detuning, and (ii) an initial amplitude; (b) at a final time point, characterized by (i) a detuning from a transition equal to a final detuning, which is substantially equal in magnitude and opposite sign to the initial detuning, and (ii) a final amplitude substantially equal to the initial amplitude; and (c) between the initial and final time points, inducing an operating signal, which includes (i) a detuning of a smooth and flat transition from the initial detuning to the final detuning, and (ii) an amplitude that increases from the initial amplitude to the maximum amplitude, then decreases from the maximum amplitude to the final amplitude, and when the detuning from the transition is equal to zero, the amplitude is equal to the maximum amplitude.

[0046] In an exemplary embodiment, the first adiabatic bond is a rapid adiabatic passage, and the second adiabatic bond is the inverse of the first adiabatic bond.

[0047] In an exemplary embodiment, the second adiabatic coupling is performed over the deshelving time.

[0048] In exemplary embodiments, the shelving time and deshelving time are in the range of 5 to 10 μs, respectively.

[0049] In an exemplary embodiment, at least one of the first adiabatic coupling or the second adiabatic coupling is a Rabi flop transition.

[0050] In exemplary embodiments, these executable instructions, when executed by a processing device, are further configured to cause a controller to use a driver controller element to control the operation of the confinement device to transport two or more quantum objects into at least one static magnetic field gradient zone prior to inducing a first adiabatic coupling.

[0051] In an exemplary embodiment, a first potential generation signal filtering scheme is used to filter potential generation signals used to transport two or more quantum objects into at least one static magnetic field gradient zone.

[0052] In an exemplary embodiment, a second potential-generating signal filtering scheme, distinct from the first potential-generating signal filtering scheme, is used to filter the potential-generating signal used to confine two or more quantum objects within a static magnetic field gradient zone during the execution of the first adiabatic coupling, the gate time period, and the execution of the second adiabatic coupling.

[0053] In an exemplary embodiment, the method further includes the step of transporting two or more quantum objects outside at least one static magnetic field gradient zone after performing a second adiabatic coupling over a deshelving time.

[0054] In an exemplary embodiment, a first potential generation signal filtering scheme is used to filter potential generation signals used to transport two or more quantum objects outside of at least one static magnetic field gradient zone.

[0055] In an exemplary embodiment, a second potential-generating signal filtering scheme, distinct from the first potential-generating signal filtering scheme, is used to filter the potential-generating signal used to confine two or more quantum objects within a static magnetic field gradient zone during the execution of the first adiabatic coupling, the gate time period, and the execution of the second adiabatic coupling.

[0056] In exemplary embodiments, the step of inducing at least one of a first adiabatic coupling or a second adiabatic coupling includes controlling the operation of the quantum system's operating source to cause at least one operating signal to be incident on two or more quantum objects located within a static magnetic field gradient zone.

[0057] In an exemplary embodiment, at least one operating signal includes at least one of a microwave signal or a laser beam.

[0058] In yet another embodiment, a computer program product is provided. In an exemplary embodiment, the computer program product comprises at least one non-temporary computer-readable medium storing executable instructions. These executable instructions are configured, when executed by a controller processing device configured to control one or more components of a quantum system having a confinement device configured to confine at least two quantum objects and (b) define at least one static magnetic field gradient zone, to cause the controller to perform a first adiabatic coupling of at least one memory state of at least two quantum objects to the respective magnetic field-sensitive states of the two or more quantum objects while the two or more quantum objects are located within at least one static magnetic field gradient zone. The first adiabatic coupling is performed over a shelving time. These executable instructions are further configured, when executed by the controller processing device, to cause the controller to perform a second adiabatic coupling of at least one memory state to the respective magnetic field-sensitive states of the two or more quantum objects while the two or more quantum objects are located within at least one static magnetic field gradient zone, in response to a determination that a gate time period has elapsed from the completion of the shelving time.

[0059] In an exemplary embodiment, two or more quantum objects become entangled within a static magnetic field gradient zone during a gate time period without using any oscillatory field to perform / mediate the entanglement of the two or more quantum objects.

[0060] In an exemplary embodiment, a static magnetic field gradient facilitates / mediates the entanglement of two or more quantum objects within the static magnetic field gradient zone.

[0061] In an exemplary embodiment, the gate time period is determined at least in part on the amount of time it takes for the static magnetic field gradient to mediate / enforce / cause entanglement of two or more quantum objects.

[0062] In exemplary embodiments, inducing a first adiabatic coupling includes (a) at an initial time point, characterized by (i) a detuning from a transition between at least one memory state and its respective magnetic field-sensitive state, equal to an initial detuning, and (ii) an initial amplitude; (b) at a final time point, characterized by (i) a detuning from a transition equal to a final detuning, which is substantially equal in magnitude and opposite sign to the initial detuning, and (ii) a final amplitude substantially equal to the initial amplitude; and (c) between the initial and final time points, inducing an operating signal, which includes (i) a detuning of a smooth and flat transition from the initial detuning to the final detuning, and (ii) an amplitude that increases from the initial amplitude to the maximum amplitude, then decreases from the maximum amplitude to the final amplitude, and when the detuning from the transition is equal to zero, the amplitude is equal to the maximum amplitude.

[0063] In an exemplary embodiment, the first adiabatic bond is a rapid adiabatic passage, and the second adiabatic bond is the inverse of the first adiabatic bond.

[0064] In an exemplary embodiment, the second adiabatic coupling is performed over the deshelving time.

[0065] In exemplary embodiments, the shelving time and deshelving time are in the range of 5 to 10 μs, respectively.

[0066] In an exemplary embodiment, at least one of the first adiabatic coupling or the second adiabatic coupling is a Rabi flop transition.

[0067] In exemplary embodiments, these executable instructions, when executed by the controller's processing device, are further configured to cause the controller to transport two or more quantum objects into at least one static magnetic field gradient zone prior to inducing a first adiabatic coupling.

[0068] In an exemplary embodiment, a first potential generation signal filtering scheme is used to filter potential generation signals used to transport two or more quantum objects into at least one static magnetic field gradient zone.

[0069] In an exemplary embodiment, a second potential-generating signal filtering scheme, distinct from the first potential-generating signal filtering scheme, is used to filter the potential-generating signal used to confine two or more quantum objects within a static magnetic field gradient zone during the execution of the first adiabatic coupling, the gate time period, and the execution of the second adiabatic coupling.

[0070] In an exemplary embodiment, the method further includes the step of transporting two or more quantum objects outside at least one static magnetic field gradient zone after performing a second adiabatic coupling over a deshelving time.

[0071] In an exemplary embodiment, a first potential generation signal filtering scheme is used to filter potential generation signals used to transport two or more quantum objects outside of at least one static magnetic field gradient zone.

[0072] In an exemplary embodiment, a second potential-generating signal filtering scheme, distinct from the first potential-generating signal filtering scheme, is used to filter the potential-generating signal used to confine two or more quantum objects within a static magnetic field gradient zone during the execution of the first adiabatic coupling, the gate time period, and the execution of the second adiabatic coupling.

[0073] In exemplary embodiments, the step of inducing at least one of a first adiabatic coupling or a second adiabatic coupling includes controlling the operation of the quantum system's operating source to cause at least one operating signal to be incident on two or more quantum objects located within a static magnetic field gradient zone.

[0074] In an exemplary embodiment, at least one operating signal includes at least one of a microwave signal or a laser beam.

[0075] Having given a general overview of the present invention, we will now refer to the attached drawings, which are not necessarily drawn to a consistent scale. [Brief explanation of the drawing]

[0076] [Figure 1] This is a block diagram of an exemplary quantum charge-coupled device (QCCD) based quantum system according to an exemplary embodiment. [Figure 2] This is a schematic top view of an exemplary confinement region of a confinement device including a static magnetic field gradient zone, according to an exemplary embodiment. [Figure 3] This is a schematic diagram of a top view of at least a portion of a confinement device according to an exemplary embodiment. [Figure 4] This flowchart illustrates the process, procedure, and / or operation for implementing a geometric phase gate according to an exemplary embodiment. [Figure 5A] This plot shows the amplitude and detuning development of the control signals used to implement the first adiabatic coupling according to various embodiments. [Figure 5B] This plot shows the amplitude and detuning development of the control signals used to implement the second adiabatic coupling according to various embodiments. [Figure 5C] This figure shows timelines for implementing geometric phase gates according to various embodiments. [Figure 6] These are exemplary partial quantum state diagrams illustrating memory subspaces and gate subspaces in various embodiments. [Figure 7] This is a schematic diagram of an exemplary controller for a quantum system, according to an exemplary embodiment. [Figure 8]This is a schematic diagram of an exemplary computational entity of a quantum system that may be used according to an exemplary embodiment. [Modes for carrying out the invention]

[0077] The present invention will be described more thoroughly below with reference to the accompanying drawings, which show some, but not all, embodiments of the invention. In fact, the invention is achievable in many different forms and should not be construed as being limited to the embodiments described herein. Rather, these embodiments are provided to satisfy the legal requirements to which this disclosure is applicable. The terms “or” (also indicated as “ / ”) are used herein in both an alternative and a conjunctive sense unless otherwise indicated. The terms “illustrative” and “exemplary” are used as examples without any indication of quality level. The terms “generally” and “approximately” mean being within appropriate engineering and / or manufacture limits and / or within user measurement capabilities, unless otherwise indicated. Similar numbers refer to similar elements throughout.

[0078] Various embodiments provide methods, quantum systems, controllers, computer program products, and the like for implementing quantum logic gates. The quantum logic gates used herein are implemented on two or more quantum objects by gate-controlling two or more quantum objects from each other and / or causing interactions between two or more quantum objects, so that the logic function of the quantum logic gate is implemented through the interaction of two or more quantum objects. In various embodiments, the quantum logic gate is a geometric phase gate involving the entanglement of two or more qubits. The entanglement of two or more qubits is implemented, mediated, and / or caused, such as by a static magnetic field gradient. Specifically, the entanglement of two or more qubits does not require any oscillatory field (e.g., a laser beam, microwaves, an oscillatory magnetic field, etc.). For example, in various embodiments of quantum logic gates, no oscillatory field is used to implement, mediate, and / or cause the entanglement of two or more qubits.

[0079] In various embodiments, the step of implementing a quantum logic gate includes the step of subjecting two or more qubits to a static magnetic field gradient. After it is determined that a gate time period has elapsed since the two or more qubits began to be subjected to the static magnetic field gradient, and / or accordingly, the two or more qubits are no longer subject to any static magnetic field gradient. In exemplary embodiments, the gate time period is determined at least in part on the amount of time it takes for the static magnetic field gradient to enforce, mediate, and / or cause entanglement of the quantum states of the two or more quantum objects.

[0080] In various embodiments, two or more qubits (for example, each implemented as a quantum object) are subjected to a static magnetic field gradient by the implementation of a first adiabatic coupling to each magnetic field-sensitive gate subspace state of at least one magnetic field-insensitive memory subspace state while they are located within the static magnetic field gradient zone of the confinement device. In various embodiments, two or more qubits (for example, each implemented as a quantum object) are no longer subjected to a static magnetic field gradient by the implementation of a second adiabatic coupling to each magnetic field-sensitive gate subspace state of at least one magnetic field-insensitive memory subspace state while they are located within the static magnetic field gradient zone of the confinement device. For example, the first and / or second adiabatic coupling may be implemented as an adiabatic Rabi-flop transition or as a rapid adiabatic passage (RAP).

[0081] Conventional implementations of quantum logic gates require an oscillatory field, such as a laser beam, microwave, or oscillating magnetic field, to implement, mediate, and / or induce entanglement of qubits. However, these oscillatory fields can introduce various gate errors, such as affecting photon scattering and / or transitions within the spectator qubit, which can lead to crosstalk problems, phase noise, and other issues. These gate errors can result in low-fidelity logic gates and noisy operations. Furthermore, quantum logic gates using oscillatory fields are highly sensitive to the state of one or more motion modes of the qubit. Therefore, spin-motion coupling can introduce further gate errors, and / or a considerable amount of time is required to cool the qubit to near its motion ground state prior to implementing the quantum logic gate. Thus, various technical problems exist regarding the implementation of quantum logic gates.

[0082] Various embodiments provide technical solutions to these technical problems. In various embodiments, quantum logic gates are implemented by using a static magnetic field gradient to implement, mediate, and / or induce entanglement of two or more qubits. Since the static magnetic field gradient is a static magnetic field (for example, substantially unchanged over time, at least during the implementation of the quantum logic gate), the quantum logic gates disclosed herein are resistant to the main mechanisms that introduce phase noise and crosstalk-related errors. In addition, the quantum logic gates of various embodiments are insensitive to the motion mode of the qubits and / or temperature. Thus, time-consuming cooling operations can be avoided and / or reduced. Accordingly, various embodiments provide improved quantum logic gates, methods for implementing improved quantum logic gates, quantum systems configured to implement improved quantum logic gates, controllers configured to cause the quantum system to implement improved quantum logic gates, and the like.

[0083] Furthermore, in order to implement quantum logic gates that are insensitive to motion errors and are mediated and / or implemented by a static magnetic field gradient, the qubit to which the quantum logic gate is implemented should be subjected to a static magnetic field gradient that turns on and / or ramps up gently compared to the qubit's motion frequency, as defined by trap confinement. This gentle turning on and / or ramping up of the qubit subjected to the static magnetic field gradient is implemented in various embodiments by transporting the qubit to be gate-controlled together into a static magnetic field gradient zone defined by the confinement device in which the static magnetic field gradient exists. The qubit is transported while in each “clock” state (e.g., with quantum number m=0, a magnetic field-insensitive state) of the memory subspace of the quantum object realizing the qubit.

[0084] Various embodiments of exemplary quantum logic gates are described next with respect to exemplary QCCD-based quantum systems.

[0085] Exemplary QCCD-based quantum systems Figure 1 provides a schematic diagram of an exemplary QCCD-based quantum system 100 that can be used to implement quantum logic gates of various embodiments. The exemplary QCCD-based quantum system 100 shown in Figure 1 is a quantum computer system comprising a quantum object confinement device 50 (e.g., an ion trap) that at least partially defines at least one static magnetic field gradient zone. For example, the confinement device 50 comprises or is physically associated with a static magnetic field gradient source 70.

[0086] In various embodiments, the static magnetic field gradient source 70 is a permanent magnet (e.g., a ferromagnet) and / or array of permanent magnets, which is either a part of the confinement device 50 (for example, located on and / or embedded in the same substrate and / or chip as the confinement device 50) or is positioned physically close to the confinement device 50 so that quantum objects confined within the static magnetic field gradient zone of the confinement device receive a static magnetic field gradient. In an exemplary embodiment, the static magnetic field gradient source 70 is an electromagnet, an array of electromagnets, and / or an array of magnets comprising at least one electromagnet and at least one permanent magnet, wherein at least one permanent magnet is either a part of the confinement device 50 (for example, located on and / or embedded in the same substrate and / or chip as the confinement device 50) or is positioned physically close to the confinement device 50 so that quantum objects confined within the static magnetic field gradient zone of the confinement device (and in a magnetic field-sensitive state, such as a gate subspace state) receive a static magnetic field gradient.

[0087] In various embodiments, the confinement device 50 is configured to confine a quantum object within one or more confinement regions defined by the confinement device 50. In various embodiments, the quantum object is a neutral or charged atom; a neutral molecule, a charged molecule, or a multipole molecule; a quantum particle; a quantum dot; or another object that can be confined by the confinement device and has a quantum state that can be manipulated through one or more operational signals and / or interactions with electrostatics and / or magnetic fields. In various embodiments, the quantum object realizes a qubit of a QCCD-based quantum system 100. In an exemplary embodiment, the confinement device 50 is an ion trap, and the quantum object is an ion.

[0088] In various embodiments, the QCCD-based quantum system 100 comprises a computing entity 10 and a quantum computer 110. In various embodiments, the quantum computer 110 comprises a controller 30 and a quantum processor 115. In various embodiments, the quantum processor 115 comprises a cryogenic and / or vacuum chamber 40 containing a confinement device 50 and a static magnetic field gradient source 70, and one or more operating sources 60. In exemplary embodiments, one or more operating sources 60 comprises one or more light sources, such as lasers and microwave sources.

[0089] In various embodiments, one or more manipulators 60 are configured to generate and / or provide manipulator signals (e.g., light beams) configured to manipulate and / or induce a controlled quantum state expansion of one or more quantum objects confined by the confinement device 50. For example, in an exemplary embodiment, one or more manipulators 60 comprises one or more lasers, which may provide one or more light beams and / or laser beams (e.g., pi pulses) to the confinement device 50 in the cryogenic and / or vacuum chamber 40 via their respective beam / signal distribution systems 66. In various embodiments, the beam / signal distribution system 66 comprises one or more optical elements, photonic integrated circuits (PICs), optical fibers, free-space optical elements, waveguides, and the like.

[0090] In various embodiments, the quantum processor 115 further comprises a plurality of voltage sources 80. The voltage sources 80 are operable (e.g., by the controller 30) to generate potential generation signals and provide them to electrical elements (e.g., electrodes) of the confinement device 50, electromagnets of any of the static magnetic field gradient sources 70, etc. In various embodiments, the potential generation signals are filtered and / or conditioned using a filter 85 prior to being applied to the control electrodes of the confinement device.

[0091] In various embodiments, the filter 85 can operate according to at least two different filtering schemes. For example, in various embodiments, the filter 85 may operate according to one of a first potential-generating signal filtering scheme or a second potential-generating signal filtering scheme. For example, the first potential-generating signal filtering scheme is configured to enable and / or smooth the efficient and / or rapid transport of quantum objects, and the second potential-generating signal filtering scheme is configured to enable and / or smooth the generation of low-noise potential wells for confining quantum objects at each location of the confinement apparatus. For example, in an exemplary embodiment, when the filter 85 operates according to the first potential-generating signal filtering scheme, the filter 85 operates to implement a low-pass filter (or a high-pass filter or band-pass filter) at a first cutoff frequency, and when the filter 85 operates according to the second potential-generating signal filtering scheme, the filter 85 operates to implement a low-pass filter (or a high-pass filter or band-pass filter) at a second cutoff frequency, in which case the first and second cutoff frequencies are different. For example, the first potential generation signal filtering method and the second potential generation signal filtering method may result in filtered potential generation signals having different spectra, different frequency profiles, different noise profiles, and so on.

[0092] In various embodiments, the computing entity 10 is configured to allow a user to provide input to the quantum computer 110 (for example, through the user interface of the computing entity 10), and to receive, view, and so on, output from the quantum computer 110. The computing entity 10 may communicate with the controller 30 of the quantum computer 110 via one or more wired or wireless networks 20 and / or via direct wired and / or wireless communication. In exemplary embodiments, the computing entity 10 can translate, configure, format, and so on, information / data, quantum computing algorithms, etc., into a computing language, executable instructions, command set, etc., that the controller 30 can understand and / or implement.

[0093] In various embodiments, the controller 30 is configured to control a voltage source 80, a filter 85, a cryogenic system and / or vacuum system that controls the temperature and pressure in the cryogenic and / or vacuum chamber 40, an operating source 60, and / or other systems that control environmental conditions (e.g., temperature, humidity, pressure, etc.) in the cryogenic and / or vacuum chamber 40, and / or to operate and / or induce a controlled development of the quantum state of one or more quantum objects (e.g., ions) confined by a confinement device 50 (e.g., an ion trap). In various embodiments, the quantum objects confined by the confinement device 50 are used as qubits in a quantum computer 110.

[0094] Figure 2 shows a top view of a portion of the confinement device 50. The indicated portion of the confinement device 50 includes radio frequency (RF) rails 210A and 210B, and three sequences of control electrodes 212A, 212B, and 212C. Each sequence of control electrodes 212 comprises a plurality of control electrodes 214. For example, the indicated portion of sequence 212A of control electrodes includes control electrodes 214A, 214B, ..., 214N.

[0095] In various embodiments, the RF voltage source of the voltage source 80 generates and provides potential generation signals (e.g., RF voltage signals) applied to RF rails 210A, 210B to generate pseudopotentials that define one or more linear confinement regions 200 of the confinement device 50. The null points of the pseudopotentials generated by the RF voltage signals applied to RF rails 210A, 210B define an RF null axis 216 that extends substantially along the centerline of the linear confinement region 200. The quantum object confined by the confinement device 50 is confined within one or more linear confinement regions 200.

[0096] In various embodiments, the confinement device 50 and the static magnetic field gradient source 70 define a static magnetic field gradient zone 230. When a quantum object is confined by the confinement device 50 within the static magnetic field gradient zone 230, the quantum object is subjected to a static magnetic field gradient. The static magnetic field gradient is referred to herein as static because the magnetic field gradient is substantially stable (e.g., unchanging) over time, at least while the quantum logic gate is being implemented within the static magnetic field gradient zone.

[0097] In various embodiments, the voltage source 80 generates and provides a potential generation signal to be applied to each control electrode 214 in a sequence of control electrodes 212. In various embodiments, the potential generation signal is filtered by a filter 85 prior to being applied to each control electrode 214. In various embodiments, the filter 85 is configured to operate in at least two different filtering schemes. For example, the filter 85 may be configured to operate according to a first potential generation signal filtering scheme when the potential generation signal is configured to cause the transport of one or more quantum objects in the confinement device. For example, the filter 85 may operate according to a first potential generation signal filtering scheme when the potential generation signal is configured to cause one or more quantum objects to be transported from one or more respective start locations to one or more respective destination locations. The filter 85 may further be configured to operate according to a second potential generation signal filtering scheme when the potential generation signal is configured to cause one or more quantum objects to retain their respective locations in the confinement device.

[0098] For example, in an exemplary embodiment, when filter 85 operates according to a first potential-generating signal filtering scheme, filter 85 operates to perform a low-pass filter (or a high-pass filter or band-pass filter) at a first cutoff frequency, and when filter 85 operates according to a second potential-generating signal filtering scheme, filter 85 operates to perform a low-pass filter (or a high-pass filter or band-pass filter) at a second cutoff frequency, in which case the first and second cutoff frequencies are different. In various embodiments, a potential-generating signal (e.g., a voltage signal) filtered according to the first potential-generating signal filtering scheme has a different noise profile, a different frequency profile, a different spectrum, etc., compared to a potential-generating signal produced by filtering the same source potential-generating signal according to the second potential-generating signal filtering scheme.

[0099] In various embodiments, the confinement device 50 and one or more beam / signal distribution systems 66 define an vibration field zone 220. In various embodiments, the vibration field zone 220 is configured such that an operation signal can be incident on a quantum object when the quantum object is placed within the vibration field zone 220. For example, the beam / signal distribution system 66 is configured such that an operation signal generated by an operation source 60 is applied to the confinement device 50 within the vibration field zone 220 so that the operation signal can be incident on a quantum object placed within the vibration field zone 220.

[0100] Quantum objects confined by the confinement device 50 can be transported between different locations of the confinement device 120 by applying a set of potential generation signal sequences to the control electrodes 212. For example, a quantum object (or a group of quantum objects) can be transported between the vibration field zone 220 and the static magnetic field gradient zone 230 and / or other locations defined by the confinement device 50. For example, the controller 30 is configured to control the voltage source 80 to trigger the execution of a transport operation of a quantum object (or a group of quantum objects) between various locations defined by the confinement device 50. In various embodiments, potential generation signals applied to the control electrodes 214 used to perform the transport operation are filtered (by filter 85) according to a first potential generation signal filtering scheme, and potential generation signals applied to the control electrodes 214 not used to perform the transport operation (e.g., used to maintain quantum objects at their respective locations) are filtered (by filter 85) according to a second potential generation signal filtering scheme.

[0101] In exemplary embodiments, the confinement device 50 comprises and / or defines a single linear confinement region 200. In various embodiments, the confinement device 50 comprises and / or defines multiple confinement regions 200 and / or arrays of confinement regions 200. Figure 3 provides a partial top view of the confinement device 50 showing a two-dimensional array of confinement regions 200 (e.g., 200A, 200B, 200C, 200D, 200E, 200F, 200G, 200H). In the embodiments shown, multiple vibration field zones 220 (e.g., 220A, 220B, 220C, 220D, 220E, 220F) and / or multiple static magnetic field gradient zones 230 (e.g., 230A, 230B, 230C, 230D, 230E, 230F) are defined along the array of confinement regions. For example, multiple vibration field zones 220 (e.g., 220A, 220B, 220C, 220D, 220E, 220F) and / or multiple static magnetic field gradient zones 230 (e.g., 230A, 230B, 230C, 230D, 230E, 230F) provide, in the shown embodiment, a periodic array of vibration field zones 220 and / or static magnetic field gradient zones, respectively.

[0102] Exemplary operation of a quantum system for implementing quantum logic gates In various systems, a quantum system such as the QCCD-based quantum system 100 can be operated to implement quantum logic gates such that a static magnetic field gradient is used to implement, mediate, and / or induce entanglement of two or more qubits corresponding to the quantum logic gate. Figure 4 provides a flowchart showing various processes, procedures, operations, etc. that may be performed (e.g., by the controller 30) to implement quantum logic gates according to various embodiments.

[0103] In various embodiments, the quantum logic gates implemented through the processes, procedures, and operations shown in Figure 4 induce entanglement of two or more qubits, which is implemented, mediated, and / or induced by a static magnetic field gradient. In various embodiments, when the quantum logic gates are implemented, no oscillatory field is used to implement, mediate, and / or induced entanglement of two or more qubits.

[0104] In various embodiments, a qubit (e.g., a quantum bit) is implemented as a quantum object. For example, the quantum state of a quantum object is used to encode information that is the result of a quantum computation. For example, a controlled expansion of the respective quantum states of multiple quantum objects results in a quantum computation. The terms quantum object and qubit are used interchangeably herein.

[0105] Depending on the determination that two or more quantum objects will interact with each other via quantum logic gates, the controller 30 can transport the two or more quantum objects to a common location. In an exemplary embodiment, the common location is within a static magnetic field gradient zone 230.

[0106] For example, in step 402, the controller 30 transports two or more quantum objects into the static magnetic field gradient zone 230, against which quantum logic gates will be performed. For example, the controller 30 may control the operation of the voltage source 80, the filter 85, and / or the confinement device 50 so that a potential well containing the two or more quantum objects is transported into the static magnetic field gradient zone 230. In various embodiments, while the two or more quantum objects are being transported into the static magnetic field gradient zone 230, they are in a magnetic field-insensitive state (e.g., a "clock" state or an m=0 state) in their respective memory subspaces. In an exemplary embodiment, a potential generation signal applied to the control electrode of the confinement device 50, configured to cause the transport of the two or more quantum objects into the static magnetic field gradient zone 230, is filtered by the filter 85 according to a first potential generation signal filtering scheme.

[0107] In step 404, the controller 30 causes two or more quantum objects, to which quantum logic gates will be performed, to remain within the static magnetic field gradient zone 230. For example, the controller 30 may control the operation of the voltage source 80, the filter 85, and / or the confinement device 50 so that the potential wells to which the two or more quantum objects are located remain within the static magnetic field gradient zone 230. In an exemplary embodiment, the potential generation signal applied to the control electrode of the confinement device 50, which is configured to cause the transport of two or more quantum objects into the static magnetic field gradient zone 230, is filtered by the filter 85 according to a second potential generation signal filtering scheme. For example, the second potential generation signal filtering scheme may be configured to cause the control electrode to which the filtered potential generation signal is applied to generate a low-noise potential well.

[0108] In step 406, the controller 30 adiabatically couples at least one of the memory subspace states to its respective gate subspace state. For example, the controller 30 may control the operation of one or more manipulators to cause one or more manipulator signals (such as microwave signals or laser beams) to be incident on two or more quantum objects located within the static magnetic field gradient zone 230 in order to induce a first adiabatic coupling. One or more manipulator signals and / or the first adiabatic coupling adiabatically couples at least one of the memory subspace states to its respective gate subspace state. In various embodiments, adiabatically couplening at least one memory subspace state to its respective gate subspace state causes the quantum object in at least one memory subspace state to transition to its respective gate subspace state in an adiabatic manner.

[0109] As those skilled in the art will understand, an adiabatic coupling or transition in an adiabatic manner is a quantum state coupling or transition that occurs loosely enough to prevent the quantum object experiencing the coupling or transition from transitioning to another eigenstate. For example, coupling and / or transitions always occur loosely with respect to the frequency difference of the instantaneous energy eigenstates of the quantum object during coupling and / or transition.

[0110] In various embodiments, the states of the memory subspace are states understood as qubit bright / dark states or |0> / |1> states. In various embodiments, the states of the memory subspace are magnetically insensitive, have quantum number m=0, and / or are “clock” states. In various embodiments, the gate subspace is defined as a subset of the quantum states of a quantum object. In various embodiments, one or more states of the gate subspace are magnetically sensitive, are Zeeman states, and / or have quantum number m≠0. Figure 6 shows a partial energy diagram illustrating some of the quantum states of a quantum object. The memory subspace 610 is defined within the ground state manifold 605 (e.g., the S manifold) of the quantum object. In the embodiments shown, the memory subspace 610 contains two quantum states, namely a first memory subspace state 612A and a second memory subspace state 612B. In the embodiment shown, the first and second memory subspace states 612A and 612B are clock states (for example, magnetic quantum number m=0).

[0111] In various embodiments, a gate subspace 620 is defined. Specifically, the gate subspace 620 is defined as comprising a first gate subspace state 622A and a second gate subspace state 622B. The first gate subspace state 622A is selected and / or chosen such that a first memory subspace state 612A can be coupled to the first gate subspace state 622A via a first operation signal 630A. For example, in an exemplary embodiment, the first operation signal 630A is a pi pulse of a laser beam characterized by a frequency that resonates or nearly resonates with the energy difference between the first memory subspace state 612A and the first gate subspace state 622A.

[0112] The second gate subspace state 622B is selected and / or chosen such that the second memory subspace state 612B can be coupled to the second gate subspace state 622B via a second operation signal 630B. For example, the second operation signal 630B is a pi pulse of a laser beam characterized by a frequency that resonates or nearly resonates with the energy difference between the second memory subspace state 612B and the second gate subspace state 622B. In exemplary embodiments, the first and second operation signals are characterized by the same frequency (for example, the frequency difference between the first memory subspace state 612A and the first gate subspace state 622A and the frequency difference between the second memory subspace state 612B and the second gate subspace state 622B may be substantially equal). In exemplary embodiments, the first and second operation signals are characterized by different frequencies.

[0113] In exemplary embodiments where the first and second memory subspace states 612A and 612B are clock states, the memory subspace states are relatively insensitive to magnetic fields. However, the gate subspace states 622A and 622B are selected or chosen to be Zeeman states with quantum number m ≠ 0, such that the gate subspace states are sensitive to magnetic fields.

[0114] The controller 30 controls the operation of one or more manipulators 60 and / or the beam / signal distribution system 66 so that one or more manipulator signals 630 (e.g., 630A, 630B) are incident on at least a portion of the static magnetic field gradient zone 230 (and thus incident on two or more quantum objects). As a result of one or more manipulator signals 630 being incident on two or more quantum objects, the quantum state of each quantum object is mapped and / or transformed from its respective memory subspace state 612 (or a superposition of memory subspace states 612) to its respective gate subspace state 622 (or a superposition of gate subspace states 622).

[0115] Various adiabatic couplings from each gate subspace state of at least one memory subspace state can be used in various embodiments. In an exemplary embodiment, the first adiabatic coupling is an adiabatic Rabi flip transition. In another exemplary embodiment, the first adiabatic coupling is a RAP.

[0116] FIG. 5A provides a plot showing, over time (during the first adiabatic coupling), the amplitude of the manipulation signal and the detuning of the frequency of the manipulation signal from the frequency corresponding to the energy difference between at least one memory subspace state and each gate subspace state in arbitrary units. FIG. 5A shows an exemplary embodiment in which the first adiabatic coupling is implemented as a RAP. For example, as shown in the timeline provided by FIG. 5C, the first adiabatic coupling starts at an initial shelving time t s0 and ends at a final shelving time t sf where, in this case, the time between the final shelving time t sf and the initial shelving time t s0 (e.g., t sf -t s0 ; the duration of the first adiabatic coupling) is the shelving time Δt shelving . In various embodiments, the shelving time Δt shelving is in the range of 0.2 to 20 μs. In another exemplary embodiment, the shelving time Δt shelving is in the range of 1 to 10 μs (e.g., 5 to 10 μs).

[0117] As shown in FIG. 5A, the controller 30 is at an initial shelving time t s0In this configuration, the operation of the control source 60 is controlled such that the control signal is characterized by (i) detuning from the transition between at least one (magnetic field insensitive) memory state and each (magnetic field sensitive) gate subspace state, which is equal to the initial detuning, and (ii) an initial amplitude. In various embodiments, the initial detuning is not equal to zero, and the initial amplitude is approximately equal to zero or slightly greater than zero. The controller 30 controls the final shelving time t sf In this configuration, the operation of the control source 60 is further controlled such that the control signal is characterized by (i) a detuning from the transition that is equal to a final detuning that is not equal to zero and has the opposite magnitude of the initial detuning, and (ii) a final amplitude that is substantially equal to the initial amplitude. In exemplary embodiments, the absolute values ​​of the initial detuning and the final detuning are substantially equal. For example, in exemplary embodiments, the final detuning is substantially equal in magnitude and opposite in sign to the initial detuning. Figure 6 shows the initial detuning δ0 and final detuning δ from the transition frequency ν1 corresponding to the energy difference between the first memory subspace state 612A and the first gate subspace state 622A. f This indicates.

[0118] In the embodiment shown in Figure 5A, the initial shelving time t s0 and final shelving time t sf During this time, the detuning transitions monotonically from initial detuning to final detuning. In the embodiments shown, the detuning transitions linearly from initial detuning to final detuning with respect to time during the shelving time. However, in various embodiments, the detuning transitions logarithmically, exponentially, quadratically, according to a step function, sinusoidally, and / or in another monotonic way with respect to time during the shelving time from initial detuning to final detuning. The detuning transitions during the shelving passage time t sc In this case, it is equal to zero, where t s0 <t sc <t sf In an exemplary embodiment, the shelving passage time t sc t is the midpoint between the initial shelving time and the final shelving time (for example, t sc -t s0 =( t sf -ts0 ) / 2). Initial shelving time t s0 and shelving passage time t sc During this time, the amplitude increases monotonically from the initial amplitude to the maximum amplitude. Shelving passage time t sc and final shelving time t sf During this time, the amplitude decreases monotonically from the maximum amplitude to the final amplitude. In the exemplary embodiment, the final amplitude is substantially equal to the initial amplitude. In the embodiment shown, the amplitude changes linearly with respect to time during the shelving time (e.g., shelving passage time t). sc It increases monotonically until the final shelving time t sf (It decreases monotonically until it reaches [a certain value]). However, in various other embodiments, the amplitude can detune logarithmically, exponentially, quadratically, according to a step function, sinusoidally, and / or in another monotonic way with respect to time during the shelving time. In various embodiments, various other adiabatic couplings may be used to implement the first adiabatic coupling.

[0119] In exemplary embodiments, a static magnetic field gradient exists within the static magnetic field gradient zone 230 prior to the transport of two or more quantum objects into the static magnetic field gradient zone 230 and / or prior to the implementation of a first adiabatic coupling. In various embodiments, the static magnetic field gradient source 70 includes one or more electromagnets, and the static magnetic field gradient zone is turned on and / or made to exist (for example, increasing to a stable state current flow with an absolute value greater than zero) as two or more quantum objects are transported into the static magnetic field gradient zone 230 and / or when two or more quantum objects are placed within the static magnetic field gradient zone 230 (but before the implementation of a first adiabatic coupling). The implementation of a first adiabatic coupling causes two or more quantum objects to receive a magnetic field gradient that exists within the static magnetic field gradient zone as a result of a population transfer from at least one (magnetic field insensitive) memory subspace state to their respective (magnetic field sensitive) gate subspace states.

[0120] Returning to Figure 4, in step 408, the controller 30, in an exemplary embodiment, causes one or more dynamic decoupling sequences to be performed on at least one of the two or more quantum objects, at which point the quantum logic gate is executed. In various embodiments, one or more dynamic decoupling sequences are performed to prevent and / or mitigate the effects of spin decoherence on at least one of the two or more quantum objects. In various embodiments, the dynamic decoupling sequence includes applying a pi pulse to at least one of the two or more qubits to flip the spin of the qubit. In an exemplary embodiment, one or more dynamic decoupling sequences include one or more Walsh sequences. In various other embodiments, various other dynamic decoupling sequences are used.

[0121] In various embodiments, one or more dynamic decoupling sequences are performed on one or more of two or more quantum objects during the gate time period. For example, in an exemplary embodiment, the gate time period Δt gate Over the gate time period Δt, one or more dynamic decoupling sequences are performed. gate At any point in the middle (for example, completion of the first adiabatic coupling (t sf (later) and the start of the second adiabatic bond (t d0 This can be performed for each quantum object (before the preceding). In various embodiments, the timing of the execution of the dynamic decoupling sequence is determined in part based on the dynamic decoupling sequence being used.

[0122] In various embodiments, the controller 30 is configured to perform a dynamic decoupling sequence on quantum objects by controlling the operation of one or more operation sources 60 and / or beam / signal distribution systems 66 to inject one or more dynamic decoupling operation signals onto each of two or more quantum objects. In an exemplary embodiment, the dynamic decoupling operation signals are pi pulses configured to correct and / or prevent errors caused by energy splitting of qubits that drift in an uncontrollable manner during the execution of a quantum logic gate.

[0123] In various embodiments, one or more dynamic decoupling operation signals are incident on each quantum object while the quantum object is located within the static magnetic field gradient zone 230. For example, in an exemplary embodiment, when it is time to perform the dynamic decoupling sequence, the static magnetic field gradient is turned off (for example, if the static magnetic field gradient source 70 includes one or more electromagnets, the current flow to the electromagnets is reduced to nominally zero), the dynamic decoupling operation signals are applied to each quantum object, and then the static magnetic field gradient is turned on again (for example, the current flow to the electromagnets increases to a stable state current flow with an absolute value greater than zero). In an exemplary embodiment, when it is time for the dynamic decoupling sequence to be performed on the quantum object, the quantum object is transported out of the static magnetic field gradient zone 230 (for example, optionally to the vibrational field zone 220), the dynamic decoupling operation signals are incident on the quantum object, and then the quantum object is transported back into the static magnetic field gradient zone 230.

[0124] In various embodiments, the clock used to determine that the gate time period has elapsed since two or more quantum objects began to receive a static magnetic field gradient and / or since the execution of the first adiabatic coupling was completed pauses during the execution of one or more dynamic decoupling sequences. In an exemplary embodiment, the gate time period is the gate time period Δt gateThe clock is determined and / or defined to include time for one or more dynamic decoupling sequences to be performed, and the clock does not pause for the performance of one or more dynamic decoupling sequences.

[0125] Continuing with Figure 4, in step 410, the controller 30 controls the gate time period Δt gate It is determined that the time elapsed is Δt. For example, the controller 30 determines that the gate time period Δt has elapsed since the completion of the first adiabatic coupling. gate It is determined that the time has elapsed. For example, the controller 30 determines that two or more quantum objects have passed the gate time period Δt gate It is determined that a magnetic field gradient is being applied over a certain period. For example, the controller 30 determines that the first adiabatic coupling is performed during a shelving time t. shelving During this process, a gate time period Δt occurs in which entanglement of the quantum logic gate and / or two or more quantum objects occurs. gate , and / or during the deshelving time t in which a second adiabatic coupling is performed deshelving The controller 30 includes or communicates with a clock, which enables it to count or track time.

[0126] In various embodiments, the gate time period is determined at least in part on the amount of time it takes for the static magnetic field gradient to implement, mediate, and / or cause entanglement of two or more quantum objects. In an exemplary embodiment, the static magnetic field gradient has a magnetic field strength and / or amplitude greater than 100 T / m, and the gate time period is 10 4 The duration is less than μs. In exemplary embodiments, the static magnetic field gradient has a magnetic field strength and / or amplitude greater than 200 T / m, and the gate time period is 3 × 10⁻⁶. 3 It is less than μs. In an exemplary embodiment, the static magnetic field gradient has a magnetic field strength and / or amplitude greater than 300 T / m, and the gate time period is 10 3It is less than μs. For example, in various embodiments, the gate time period is determined at least in part on a function of the magnetic field strength and / or amplitude of the static magnetic field gradient, the motion frequency of one or more motion modes of the quantum object, etc.

[0127] Gate time period Δt gate If it is determined that the time has elapsed, the process proceeds to step 412. In step 412, the controller 30 adiabatically couples at least one of the memory subspace states to its respective gate subspace state. For example, for each memory subspace state adiabatically coupled to its respective gate subspace state during the first adiabatically coupled, the memory subspace state is again adiabatically coupled to its respective gate subspace state during the second adiabatically coupled. For example, the first adiabatically coupled transitions a quantum object (located within the static magnetic field gradient zone) from at least one memory subspace state to its respective gate subspace state so that the quantum object is subject to a magnetic field gradient. The second adiabatically coupled transitions a quantum object (located within the static magnetic field gradient zone) from its respective gate subspace state to its respective at least one memory subspace state so that the quantum object is substantially stopped from being subject to a magnetic field gradient.

[0128] For example, the controller 30 may control one or more manipulation sources to inject one or more manipulation signals onto two or more quantum objects located within the static magnetic field gradient zone 230 in order to induce a second adiabatic coupling. One or more manipulation signals and / or the second adiabatic coupling adiabaticly couple each gate subspace state to each of at least one memory subspace states. In various embodiments, adiabatic coupling of each gate subspace state to each of at least one memory subspace states causes the quantum object in each gate subspace state to transition to each of at least one memory subspace state in an adiabatic manner.

[0129] As explained above, adiabadic coupling, or transitions in an adiabadic manner, are quantum state couplings or transitions that occur without heat transfer between a system (e.g., a quantum object) and its environment. In other words, the motion state of a quantum object is not affected by or modified by transitions in an adiabadic manner. For example, the internal quantum state of a quantum object may be modified without modifying the motion state of the quantum object as a result of adiabadic coupling of at least one memory subspace state to each of its gate subspace states.

[0130] For example, the controller 30 controls the operation of one or more manipulators 60 and / or the beam / signal distribution system 66 to inject one or more manipulator signals 630 (e.g., 630A, 630B) onto at least a portion of the static magnetic field gradient zone 230 (and thus onto two or more quantum objects). As a result of one or more manipulator signals 630 being injected onto two or more quantum objects, the quantum state of each quantum object is mapped and / or transformed from its respective gate subspace state 622 (or a superposition of gate subspace states 622) to its respective memory subspace state 612 (or a superposition of memory subspace states 612).

[0131] In various embodiments, various adiabatic couplings may be used to each gate subspace state of at least one memory subspace state. In an exemplary embodiment, the first adiabatic coupling is an adiabatic Rabi flip transition. In another exemplary embodiment, the first adiabatic coupling is a RAP.

[0132] Figure 5B provides a plot showing, in arbitrary units, the amplitude of the operation signal over time (during the second adiabatic coupling) and the detuning of the operation signal frequency from the frequency corresponding to the energy difference between at least one memory subspace state and each gate subspace state. Figure 5B shows an exemplary embodiment in which the second adiabatic coupling is performed as RAP. For example, as shown in the timeline provided by Figure 5C, the second adiabatic coupling starts at an initial deshelving time td0 and ends at a final deshelving time t df The process ends here, and the final deshelving time t df and initial deshelving time t d0 The time between (for example, t df -t d0 The duration of the second adiabatic bond is the deshelving time Δt. deshelving In various embodiments, the deshelving time Δtdeshelving This is in the range of 0.2 to 20 μs. In another exemplary embodiment, the deshelving time Δt deshelving This is within the range of 1 to 10 μs (for example, 5 to 10 μs).

[0133] As shown in Figure 5B, the controller 30 has an initial deshelving time t d0 In this configuration, the operation of the control source 60 is controlled such that the control signal is characterized by (i) a detuning from the transition between at least one (magnetic field insensitive) memory state and each (magnetic field sensitive) gate subspace state, which is equal to the initial detuning, and (ii) an initial amplitude. In various embodiments, the initial detuning is not equal to zero, and the initial amplitude is approximately equal to zero or slightly greater than zero. In an exemplary embodiment, the initial detuning of the second adiabatic coupling is substantially equal to the final detuning of the first adiabatic coupling. The controller 30 controls the final deshelving time t df In this configuration, the operation of the control source 60 is further controlled such that the control signal is characterized by (i) a detuning from the transition that is equal to a final detuning that is not equal to zero and has the opposite magnitude to the initial detuning, and (ii) a final amplitude that is substantially equal to the initial amplitude. In exemplary embodiments, the absolute values ​​of the initial detuning and the final detuning are substantially equal. For example, in exemplary embodiments, the final detuning is substantially equal in magnitude and opposite in sign to the initial detuning.

[0134] In the embodiment shown in Figure 5B, the initial deshelving time t d0 Between the deshelving time tdf and the final deshelving time, the detuning transitions monotonically from initial detuning to final detuning. In the embodiments shown, the detuning transitions linearly with respect to time during the deshelving time from initial detuning to final detuning. However, in various embodiments, the detuning transitions logarithmically, exponentially, quadratically, according to a step function, sinusoidally, and / or in another monotonic way with respect to time during the deshelving time from initial detuning to final detuning. The detuning transitions through the deshelving time t dc In this case, it is equal to zero, where t d0 <t dc <tdf In an exemplary embodiment, the deshelving passage time t dc is the midpoint between the initial deshelling time and the final deshelling time (for example, t dc -t d0 =( t df -t d0 ) / 2). Initial deshelving time t d0 and deshelving passage time t dc During this time, the amplitude increases monotonically from the initial amplitude to the maximum amplitude. (Deshelving transit time t) dc and final deshelving time t df During this time, the amplitude decreases monotonically from the maximum amplitude to the final amplitude. In various embodiments, the initial amplitude and / or final amplitude are the minimum amplitudes. In exemplary embodiments, the final amplitude is substantially equal to the initial amplitude. In the embodiments shown, the amplitude changes linearly with respect to time during the deshelving time (e.g., deshelving passage time t). dc It increases monotonically until the final deshelving time t sf (It decreases monotonically to a certain point). However, in various other embodiments, the amplitude can detune logarithmically, exponentially, quadratically, according to a step function, sinusoidally, and / or in another monotonic way with respect to time during the deshelving time. For example, in an exemplary embodiment, the second adiabatic coupling is the first adiabatic coupling performed in reverse. In various embodiments, various other adiabatic couplings may be used to perform the first adiabatic coupling.

[0135] The implementation of the second adiabatic coupling effectively halts the magnetic field gradient present in the static magnetic field gradient zone to two or more quantum objects as a result of the distributional transition from each (magnetic field-sensitive) gate subspace state to each at least one (magnetic field-insensitive) memory subspace state.

[0136] Continuing with Figure 4, in step 414, the controller 30 transports two or more quantum objects, against which a quantum logic gate has been implemented, out of the static magnetic field gradient zone 230. For example, the controller 30 may control the operation of the voltage source 80, the filter 85, and / or the confinement device 50 so that the potential well in which the two or more quantum objects are located is transported out of the static magnetic field gradient zone 230. In various embodiments, the two or more quantum objects are in a magnetic field-insensitive state (e.g., a "clock" state or m=0 state) in their respective memory subspaces while the two or more quantum objects are transported out of the static magnetic field gradient zone 230. In an exemplary embodiment, the potential generation signal applied to the control electrode of the confinement device 50 configured to cause the transport of two or more quantum objects from the static magnetic field gradient zone 230 is filtered by the filter 85 according to a first potential generation signal filtering scheme.

[0137] After the execution of a quantum logic gate is complete, the controller 30 can continue to control the operation of various components of the quantum processor 115 so that the quantum processor 115 continues and / or terminates the execution of quantum circuits and / or algorithms that include quantum logic gates. For example, each of two or more quantum objects can be transported, have one or more single-qubit gates executed on it, have one or more qubit gates executed on it, or have one or more read operations executed on it, according to its quantum circuit and / or algorithm.

[0138] As can be understood, the operational signals used to couple and / or map the quantum states of two or more quantum objects from memory subspace states to gate subspace states, and vice versa, and any dynamic decoupling operational signals used to perform one or more dynamic decoupling sequences, each operate independently with respect to a single quantum object. In other words, the operational signals used to couple and / or map the quantum states of two or more quantum objects from memory subspace states to gate subspace states, and any dynamic decoupling operational signals, do not perform, mediate, and / or cause any interaction and / or entanglement between two or more quantum objects. Interaction and / or entanglement between two or more quantum objects is performed, mediated, and / or caused solely by the static magnetic field gradient.

[0139] Technical advantages Conventional implementations of quantum logic gates require an oscillatory field, such as a laser beam, microwave, or oscillating magnetic field, to implement, mediate, and / or induce entanglement of qubits. However, these oscillatory fields can introduce various gate errors, such as affecting photon scattering and / or transitions within the spectator qubit, which can lead to crosstalk problems, phase noise, and other issues. These gate errors can result in low-fidelity logic gates and noisy operations. Furthermore, quantum logic gates using oscillatory fields are highly sensitive to the state of one or more motion modes of the qubit. Therefore, spin-motion coupling can introduce further gate errors, and / or a considerable amount of time is required to cool the qubit to near its motion ground state prior to implementing the quantum logic gate. Thus, various technical problems exist regarding the implementation of quantum logic gates.

[0140] Various embodiments provide technical solutions to these technical problems. In various embodiments, quantum logic gates are implemented by using a static magnetic field gradient to implement, mediate, and / or induce entanglement of two or more qubits. Since the static magnetic field gradient is a static magnetic field (for example, substantially unchanged over time, at least during the implementation of the quantum logic gate), the quantum logic gates disclosed herein are resistant to the main mechanisms that introduce phase noise and crosstalk-related errors. Since a light beam is not used to implement, mediate, or induce entanglement of two or more quantum objects, the error source of photon scattering is reduced. In addition, the quantum logic gates of various embodiments are not sensitive to the motion mode of qubits and / or temperature. Thus, time-consuming cooling operations can be avoided and / or reduced. Accordingly, various embodiments provide improved quantum logic gates, methods for implementing improved quantum logic gates, quantum systems configured to implement improved quantum logic gates, controllers configured to cause the quantum system to implement improved quantum logic gates, and the like.

[0141] Furthermore, the qubit on which a quantum logic gate is implemented, which is mediated and / or implemented by a static magnetic field gradient and is insensitive to motion errors, should be subjected to a static magnetic field gradient that turns on and / or ramps up gently compared to the qubit's motion frequency, as defined by trap confinement. This gentle turning on and / or ramping up of the qubit subjected to the static magnetic field gradient is implemented in various embodiments by transporting the qubit to be gate-controlled together into a static magnetic field gradient zone defined by the confinement device in which the static magnetic field gradient exists. The qubit is transported while in each “clock” state (e.g., with quantum number m=0, a magnetic field insensitive state) of the memory subspace of the quantum object realizing the qubit.

[0142] Example Controller In various embodiments, the confinement device 50 and the associated at least one static field gradient source 70 defining at least one static field gradient zone 230 are part of the QCCD-based quantum system 100 or other quantum system. In various embodiments, the QCCD-based quantum system 100 or other quantum system includes, for example, a controller 30 configured to control the operation of various components of a quantum processor 115. For example, the controller 30 is configured to control a voltage source 80 configured to provide a potential generation signal to a sequence of control electrodes 212 of the confinement device 50. For example, the controller 30 is configured to control the operation of a filter 85 configured to filter the potential generation signal provided to the sequence of control electrodes 212 of the confinement device 50. The controller 30 is further configured to control the cryogenic system and / or vacuum system that controls the temperature and pressure within the cryogenic and / or vacuum chamber 40, the operating source 60, the beam / signal distribution system 66, and / or other systems that control environmental conditions (e.g., temperature, humidity, pressure, etc.) within the cryogenic and / or vacuum chamber 40, and / or can be configured to manipulate and / or induce a controlled development of the quantum state of one or more quantum objects confined by the atomic object confinement device 50.

[0143] As shown in Figure 7, in various embodiments, the controller 30 may comprise various controller elements, including a processing device 705, memory 710, driver controller element 715, communication interface 720, analog-to-digital converter element 725, and so on. For example, the processing device 705 may comprise one or more processing elements, such as programmable logic devices (PLDs), microprocessors, coprocessing entities, application-specific instruction-set processors (ASIPs), integrated circuits, application-specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), programmable logic arrays (PLAs), hardware accelerators, other processing devices and / or circuits, and / or controllers. The term "circuit" may refer to an entirely hardware embodiment or a combination of hardware and computer program products. In an exemplary embodiment, the processing device 705 of the controller 30 comprises and / or communicates with a clock.

[0144] For example, memory 710 may include non-temporary memory such as volatile and / or non-volatile memory storage, such as one or more of the following: 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 710 may store qubit records corresponding to the qubits of a quantum computer (e.g., in a qubit record data store, qubit record database, qubit record table, etc.), calibration tables, executable queues, computer program code (e.g., one or more computer languages, dedicated controller languages, etc.), etc. In exemplary embodiments, the execution of at least a portion of computer program code stored in memory 710 (for example, by processing device 705) causes controller 30 to perform one or more steps, operations, processes, procedures, etc., as described herein, to track the phases of atomic objects in an atomic system and cause phase adjustments of one or more operating sources and / or signals generated thereby.

[0145] In various embodiments, the driver controller element 715 may include one or more driver and / or controller elements, each configured to control one or more drivers. In various embodiments, the driver controller element 715 may include drivers and / or driver controllers. 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., processing device 705). In various embodiments, the driver controller element 715 may enable the controller 30 to operate an operating source 60 to provide one or more operating signals, a voltage source 80 to provide respective potential generation signals to their respective control electrodes 214, a filter 85 to filter potential generation signals (e.g., according to a first and / or second potential generation signal filtering scheme), an electromagnet of any of the static magnetic field gradient sources 70, etc. In various embodiments, the driver controller element 715 may enable the controller 30 to control and / or operate various drivers (e.g., laser drivers, vacuum component drivers, cryogenic and / or vacuum system component drivers, etc.).

[0146] In various embodiments, the controller 30 includes means for communicating and / or receiving signals from one or more optical receiver components, such as a camera, MEM camera, CCD camera, photodiode, or photomultiplier tube. For example, the controller 30 may include one or more analog-to-digital converter elements 725 configured to receive signals from one or more optical receiver components, a calibration sensor, or the like.

[0147] In various embodiments, the controller 30 may include a communication interface 720 for interfaceing with and / or communicating with the computing entity 10. For example, the controller 30 may include a communication interface 720 for receiving executable instructions, command sets, etc., from the computing entity 10 and providing outputs and / or processing results of outputs received from the quantum computer 110 (e.g., from an optical collection system) to the computing entity 10. In various embodiments, the computing entity 10 and the controller 30 may communicate via direct wired and / or wireless connections and / or one or more wired and / or wireless networks 20.

[0148] Exemplary Computing Entity Figure 8 provides an exemplary schematic diagram of an exemplary computing entity 10 that may be used in conjunction with embodiments of the present invention. In various embodiments, the computing entity 10 is configured to allow a user to provide input to a quantum computer 110 (for example, through the user interface of the computing entity 10) and to receive, display, analyze, and so on outputs from the quantum computer 110.

[0149] As shown in Figure 8, the computing entity 10 may include an antenna 812, a transmitter 804 (e.g., wireless), a receiver 806 (e.g., wireless), and a processing element 808 that provides signals to the transmitter 804 and receives signals from the receiver 806, respectively. The signals provided to the transmitter 804 and received from the receiver 806 may each include signaling information / data according to wireless system air interface standards applicable for communication with various entities, such as the controller 30 and other computing entities 10. In this regard, the computing entity 10 may be capable of operating with one or more air interface standards, communication protocols, modulation types, and access types. In various embodiments, the computing entity 10 includes a network interface 820 configured to enable communication between the computing entity 10 and the controller 30 and / or various other computing devices. For example, computing entity 10 may be configured to receive and / or provide communications using wired data transmission protocols 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, computing entity 10 may be configured to receive and / or provide communications using general packet radio service (GPRS), Universal Mobile Telecommunications System (UMTS), Code Division Multiple Access 2000 (CDMA2000), CDMA20001X (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 Computing entity 10 may be configured to communicate over a wireless external communication network using any of a variety of protocols, including 802.11 (Wi-Fi), Wi-Fi Direct, 802.16 (WiMAX), ultra-wideband (UEB), 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 use such protocols and standards to communicate over a wireless external communication network using Border Gateway Protocol (BGP), Dynamic Host Configuration Protocol (DHCP), Domain Name System (DNS).Communication can be conducted using protocols such as the System, 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), and HyperText Markup Language (HTML).

[0150] Through these communication standards and protocols, computing entity 10 may 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 (DTMF) signaling, and / or subscriber identity module dialer (SIM dialer). Computing entity 10 may also download changes, add-ons, and updates to, for example, its firmware, software (including executable instructions, applications, and program modules), and operating system.

[0151] The computing entity 10 may include a user interface device comprising one or more user input / output interfaces (for example, a display 816 and / or speaker / speaker driver coupled to the processing element 808, and a touchscreen, keyboard, mouse, and / or microphone coupled to the processing element 808). For example, a user output interface is configured to provide, as used herein, applications, browsers, user interfaces, interfaces, dashboards, screens, web pages, pages, and / or displays or audible representations of information / data, which run interchangeably on the computing entity 10 and / or are accessible through one or more user input interfaces. A user input interface may comprise any of several devices that enable the computing entity 10 to receive data, such as a keypad 818 (hard or soft), a touch display, a voice / speech or motion interface, a scanner, a reader, or other input device. In embodiments including a keypad 818, the keypad 818 may include (or display) other keys, which may include conventional numeric keys (0-9) and related keys (#, *), as well as a set of keys used to operate the computing entity 10 and which can be activated to provide a full set of alphanumeric keys or a full set of alphanumeric keys. In addition to providing input, the user input interface may be used to activate or deactivate several functions, such as a screen saver and / or sleep mode. Through such input, the computing entity 10 may collect information / data, user interaction / input, etc.

[0152] The computing entity 10 may include volatile storage or memory 822 and / or non-volatile storage or memory 824, which may be embeddable 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, register memory, etc. The 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, bytecode, compiled code, interpreted code, machine code, executable instructions, etc., for implementing the functions of the computing entity 10.

[0153] conclusion Many modifications and other embodiments of the invention described herein will come to mind to those skilled in the art who benefit from the teachings presented in the foregoing description and the accompanying drawings. It should be understood that the invention is not limited to the specific embodiments disclosed, and modifications and other embodiments are intended to be included within the scope of the appended claims. Certain terms are used herein, but these are used only in a general descriptive sense and not for limitation. [Explanation of Symbols]

[0154] 10 Computing Entities 20 Wired or wireless networks 30 controllers 40 Cryogenic and / or vacuum chambers 50 Quantum object confinement device, confinement device 60 Control room 66 Beam / Signal Distribution System 70 Static magnetic field gradient source 80 Voltage source 85 Filters 100 QCCD-based quantum systems 110 Quantum Computers 115 Quantum Processors 200 Linear confinement region, confinement region 200A~H Confinement region 210A Radio Frequency (RF) Rail 210B Radio Frequency (RF) Rail 212 Control electrodes 212A~C Control electrode sequence 214 Control electrodes 214A~N control electrodes 216 RF Null Axis 220 Vibration Field Zones 220A~F Vibration field zone 230 Static magnetic field gradient zone 230A~F Static magnetic field gradient zone 605 Ground State Manifold 610 memory subspaces 612 Memory subspace states 612A First memory subspace state 612B Second memory subspace state 620 Gate Subspace 622 Gate Subspace State 622A First gate subspace state, gate subspace state 622B Second gate subspace state, gate subspace state 630 Control signal 630A First control signal 630B Second control signal 705 Processing Devices 710 memory 715 Driver Controller Element 720 Communication Interface 725 Analog-to-Digital Converter Element 804 Transmitter 806 Receiver 808 processing elements 812 Antenna 816 displays 818 Keypad 820 Network Interfaces 822 Volatile storage or memory 824 Non-volatile storage or memory

Claims

1. A method for implementing a geometric phase gate, which is carried out by a controller configured to control the operation of one or more components of a quantum system having a confinement device configured to confine at least two quantum objects and (b) define at least one static magnetic field gradient zone, A step of causing a first adiabatic coupling of at least one memory state of at least two of the quantum objects to the respective magnetic field-sensitive states of the two or more quantum objects, while two or more quantum objects are positioned within the at least one static magnetic field gradient zone, wherein the first adiabatic coupling is performed over a shelving time. In response to the determination that the gate time period has elapsed since the completion of the shelving time, the steps include: causing a second adiabatic coupling of the at least one memory state to the respective magnetic field-sensitive state while the two or more quantum objects are positioned within the at least one static magnetic field gradient zone; Methods that include...

2. The method according to claim 1, wherein the two or more quantum objects become entangled within the static magnetic field gradient zone during the gate time period without using any vibration field to carry out the entanglement of the two or more quantum objects.

3. The method according to claim 1, wherein the static magnetic field gradient causes the two or more quantum objects to become entangled within the static magnetic field gradient zone.

4. The method according to claim 3, wherein the gate time period is determined at least in part on the amount of time it takes for the static magnetic field gradient to mediate / enforce / cause the entanglement of the two or more quantum objects.

5. The method according to claim 1, wherein the step of inducing the first adiabatic coupling is characterized at (a) at an initial time point by (i) a detuning from the transition between the at least one memory state and the respective magnetic field-sensitive states, equal to an initial detuning, and (ii) an initial amplitude; (b) at a final time point by (i) a detuning from the transition, equal to a final detuning, which is substantially equal in magnitude and opposite sign to the initial detuning, and (ii) a final amplitude substantially equal to the initial amplitude; and (c) between the initial and final time points by (i) a detuning of a smooth and monotonic transition from the initial detuning to the final detuning, and (ii) an amplitude increasing from the initial amplitude to a maximum amplitude, then decreasing from the maximum amplitude to the final amplitude, and when the detuning from the transition is equal to zero, the amplitude is equal to the maximum amplitude.

6. The method according to claim 1, wherein the first adiabatic bond is a rapid adiabatic passage and the second adiabatic bond is the inverse of the first adiabatic bond.

7. The method according to claim 6, wherein the second adiabatic coupling is performed over a deshelving time.

8. The method according to claim 7, wherein the shelving time and the deshelving time are each in the range of 5 to 10 μs.

9. The method according to claim 7, wherein at least one of the first adiabatic coupling or the second adiabatic coupling is a Rabi flop transition.

10. The method according to claim 1, further comprising the step of transporting the two or more quantum objects into the at least one static magnetic field gradient zone prior to the step of causing the first adiabatic coupling.

11. The method according to claim 10, wherein the first potential generation signal filtering method is used to filter the potential generation signal used to transport the two or more quantum objects into the at least one static magnetic field gradient zone.

12. The method according to claim 11, wherein a second potential generation signal filtering method, different from the first potential generation signal filtering method, is used to filter the potential generation signal used to confine the two or more quantum objects within the static magnetic field gradient zone during the implementation of the first adiabatic coupling, the gate time period, and the implementation of the second adiabatic coupling.

13. The method according to claim 1, further comprising the step of transporting the two or more quantum objects out of the at least one static magnetic field gradient zone after performing the second adiabatic coupling over a deshelving time.

14. The method according to claim 13, wherein the first potential generation signal filtering scheme is used to filter the potential generation signal used to transport the two or more quantum objects outside the at least one static magnetic field gradient zone.

15. The method according to claim 14, wherein a second potential generation signal filtering method, different from the first potential generation signal filtering method, is used to filter the potential generation signal used to confine the two or more quantum objects within the static magnetic field gradient zone during the implementation of the first adiabatic coupling, the gate time period, and the implementation of the second adiabatic coupling.

16. The method according to claim 1, wherein the step of causing at least one of the first adiabatic coupling or the second adiabatic coupling includes controlling the operation of the operation source of the quantum system to cause at least one operation signal to be incident on the two or more quantum objects located within the static magnetic field gradient zone.

17. The method according to claim 16, wherein the at least one operating signal includes at least one of a microwave signal or a laser beam.

18. A system configured to implement geometric phase gates, (a) a confinement device configured to confine at least two quantum objects, and (b) defining at least one magnetic field gradient zone, A controller configured to control the operation of the aforementioned confinement device and The controller comprises at least, The first adiabatic coupling of at least one memory state of at least two of the quantum objects to the respective magnetic field-sensitive states of the two or more quantum objects, while two or more quantum objects are positioned within the at least one magnetic field gradient zone, wherein the first adiabatic coupling is performed over a shelving time. In response to the determination that the gate time period has elapsed since the completion of the shelving time, a second adiabatic coupling is to be made between the at least one memory state and the respective magnetic field-sensitive state while the two or more quantum objects are positioned within the at least one magnetic field gradient zone. A system configured to perform the following actions.

19. The system according to claim 18, wherein the first adiabatic coupling is a rapid adiabatic passage, and the second adiabatic coupling is the inverse of the first adiabatic coupling.

20. A controller configured to control one or more components of a quantum system to cause the quantum system to perform a geometric phase gate, wherein the quantum system comprises a confinement device configured to confine (a) at least two quantum objects and (b) define at least one magnetic field gradient zone, and the controller is at least The method involves causing a first adiabatic coupling of at least one memory state of at least two of the quantum objects to the respective magnetic field-sensitive states of the two or more quantum objects while two or more quantum objects are positioned within the at least one magnetic field gradient zone, wherein the first adiabatic coupling is performed over a shelving time. In response to the determination that the gate time period has elapsed since the completion of the shelving time, a second adiabatic coupling is to be made between the at least one memory state and the respective magnetic field-sensitive state while the two or more quantum objects are positioned within the at least one magnetic field gradient zone. A controller configured to perform the following actions.

Images