Abstract: Embodiments described herein are generally related to a method and a system for performing a computation using a hybrid quantum-classical computing system, and, more specifically, to providing an approximate solution to a combinatorial optimization problem using a hybrid quantum-classical computing system that includes a group of trapped ions. A hybrid quantum-classical computing system that is able to provide a solution to a combinatorial optimization problem may include a classical computer, a system controller, and a quantum processor. The methods and systems described herein include an efficient method for an optimization routine executed by the classical computer in solving a problem in a hybrid quantum-classical computing system, which can provide improvement over the conventional method for an optimization by conventional stochastic optimization methods.

Abstract: Aspects of the present disclosure may include a method and/or a system for identifying an ion chain having a plurality of trapped ions, selecting at least two non-consecutive trapped ions in the ion chain for implementing a qubit, applying at least a first Raman beam to shuttle at least one neighbor ion of the at least two non-consecutive trapped ions from a ground state to a metastable state, and applying at least a second Raman beam to one or more of the at least two non-consecutive trapped ions, after shuttling the at least one neighbor ion to the metastable state, to transition from a first manifold to a second manifold.

Abstract: Embodiments described herein are generally related to a method and a system for constructing and delivering a pulse to perform an entangling gate operation between two trapped ions during a quantum computation, and more specifically, to a method of demodulating and spline interpolating a pulse that can be practically implemented in the system while increasing the fidelity of the entangling gate operation, or the probability that at least two ions are in the intended qubit state(s) after performing the entangling gate operation between the two ions.

Abstract: Systems and techniques are provided for pulse generation. A classical computing device may receive a program source code including quantum operations. The program source code may be compiled into a compiled program including the one or more quantum operations. Pulse shapes that a pulse shape library indicates corresponds to each of the quantum operations may be determined. Pulse instructions based on the one or more pulse shapes that the pulse shape library indicates corresponds to each of the quantum operations may be generated. Binary format instructions may be generated based on the pulse instructions. The binary format instruction may encode the pulse instructions in binary packets using a binary code of a field programmable gate array (FPGA) of a quantum computing device.

Abstract: A method for performing an entangling operation between trapped ions in a quantum computer includes selecting an amount of infidelity that is allowed in an entangling operation between two trapped ions in a quantum computer, computing a pulse function of a pulse to be applied to each of the two trapped ions based on gate operation conditions and the selected amount of infidelity, generating the pulse based on the computed pulse function, and applying the generated pulse to each of the two trapped ions to perform the entangling operation between the two trapped ions.

Abstract: Aspects of the present disclosure describe techniques for cooling motional states in an ion trap for quantum computers. In an aspect, a method includes performing Doppler cooling and sideband cooling to sweep motional states associated with a motional mode to a zero motional state; applying a gate interaction on a red sideband; detecting, a population of non-zero motional states of the motional mode that remains after performing the Doppler cooling and the sideband cooling; and removing at least part of the population. In another aspect, a method includes performing a Doppler cooling; applying a gate interaction on a red sideband; detecting whether a population of non-zero motional states of the motional mode remains after performing the Doppler cooling; and redistributing the population of the non-zero motional states by Doppler cooling when a population is detected. A quantum information processing (QIP) system that performs these methods is also described.

Abstract: Aspects of the present disclosure describe techniques for fast stabilization of multiple controller beams with continuous integrating filter. For example, a method is described for intensity stabilization of laser beams (e.g., ion controller beams) in a trapped ion system, where the method includes applying a linear array of laser beams to respective ions in a linear array of ions in a trap, performing, in response to the laser beams being applied, parallel measurements on the ions, the parallel measurements including multiple, separate measurements on each of the ions to identify fluctuations in intensity in the respective laser beams at each ion, and adjusting the intensity of one or more of the laser beams in response to fluctuations being identified from the parallel measurements. A corresponding system for intensity stabilization of laser beams in a trapped ion system is also described.

Abstract: A shaped central electrode is described that is placed between a pair of radio frequency (RF) rails of a trap configured to hold atomic-based qubits to control aspects of the operation of the trap. In one aspect, the shaping may involve forming a pinched region in the middle of the central electrode. The middle of the central electrode may correspond to the middle portion of the trap. The shaping of the central electrode may be achieved in different ways and may involve varying the width of the central electrode. The trap may be fabricated on a glass die or substrate, which itself may be shaped or not. The trap may be fabricated by various methods such as, but not limited to, patterned metal layers on glass or silicon substrates. A quantum information processing (QIP) system is also described that may include a trap having any of these features.

Abstract: A method of performing a quantum computation process includes mapping logical qubits to physical qubits of a quantum processor so that quantum circuits are executable using the physical qubits of the quantum processor and a total infidelity of the plurality of quantum circuits is minimized, wherein each of the physical qubits comprise a trapped ion, and each of the plurality of quantum circuits comprises single-qubit gates and two-qubit gates within the plurality of the logical qubits, calibrating two-qubit gates within a first plurality of pairs of physical qubits, such that infidelity of the two-qubit gates within the first plurality of pairs of physical qubit is lowered, executing the plurality of quantum circuits on the quantum processor, by applying laser pulses that each cause a single-qubit gate operation and a two-qubit gate operation in each of the plurality of quantum circuits on the plurality of physical qubits, measuring population of qubit states of the physical qubits in the quantum processor, a

Abstract: Aspects of the present disclosure describe controlling coherent crosstalk errors in multi-channel acousto-optic modulators (AOMs). A method, an AOM system, and a quantum information processing (QIP) system are described in which a separate radio-frequency (RF) signal is generated and applied to each of multiple channels of a multi-channel AOM using an arbitrary waveform generator (AWG) to turn on each of those channels, where each channel that is turned on interacts with one or more of the remaining channels that are not turned on to cause a combined crosstalk effect on those remaining channels. Each channel has a single respective AWG. Moreover, a correcting RF signal is generated and applied to the one or more of the remaining channels using a respective AWG to produce an acoustic wave that corrects for the combined crosstalk effect such that the one or more of the remaining channels are not unintentionally turned on.

Abstract: A method of performing an entangling gate operation using a quantum computer system includes configuring, by a classical computer, an amplitude function of an amplitude-modulated laser pulse over a plurality of time segments to cause entangling interaction between a pair of trapped ions of a plurality of trapped ions, each of the plurality of trapped ions having two frequency-separated states defining a qubit, where the amplitude function in each time segment is splined using a set of basis functions and associated control parameters, and performing an entangling gate operation between the pair of trapped ions by applying, by a system controller, an amplitude-modulated laser pulse having the configured amplitude function to the pair of trapped ions.

Abstract: Aspects of the present disclosure may include a method and/or a system for identifying an ion chain having a plurality of trapped ions, selecting at least two non-consecutive trapped ions in the ion chain for implementing a qubit, applying at least a first Raman beam to shuttle at least one neighbor ion of the at least two non-consecutive trapped ions from a ground state to a metastable state, and applying at least a second Raman beam to one or more of the at least two non-consecutive trapped ions, after shuttling the at least one neighbor ion to the metastable state, to transition from a first manifold to a second manifold.

Abstract: Aspects of the present disclosure may include a method and/or a system for identifying an ion chain having a plurality of trapped ions, selecting at least two non-consecutive trapped ions in the ion chain for implementing a qubit, applying at least a first Raman beam to shuttle at least one neighbor ion of the at least two non-consecutive trapped ions from a ground state to a metastable state, and applying at least a second Raman beam to one or more of the at least two non-consecutive trapped ions, after shuttling the at least one neighbor ion to the metastable state, to transition from a first manifold to a second manifold.

Abstract: Aspects of the present disclosure may include a method and/or a system for identifying an ion chain having a plurality of trapped ions, selecting at least two non-consecutive trapped ions in the ion chain for implementing a qubit, applying at least a first Raman beam to shuttle at least one neighbor ion of the at least two non-consecutive trapped ions from a ground state to a metastable state, and applying at least a second Raman beam to one or more of the at least two non-consecutive trapped ions, after shuttling the at least one neighbor ion to the metastable state, to transition from a first manifold to a second manifold.

Abstract: The disclosure describes various aspects of a software-defined quantum computer. For example, a software-defined quantum computing architecture for allocating qubits is described that includes an application programming interface (API); a quantum operating system (OS) on which the API executes, with the quantum OS including a resource manager and a switch; and a plurality of quantum cores connected by the switch of the quantum resource OS. Moreover, the resource manager of the quantum resource OS determines an allocation of a plurality of qubits in the plurality of quantum cores.

Abstract: The disclosure describes various aspects of a software-defined quantum computer. For example, a method is described for generating an intermediate representation of source code for a software-defined quantum computer. The method includes performing a lexical analysis on a high-level intermediate representation of a quantum programming language; performing semantic analysis on an output of the lexical analysis; and generating a mid-level intermediate representation of the quantum programming language based on an output of the semantic analysis.

Abstract: Technologies are described herein to implement quantum hybrid computations. Embodiments include receiving a hybrid program, assigning respective functions corresponding to the hybrid program to either of CPU processing or QPU processing, scheduling processing for the respective functions, initiating execution of the hybrid program, and collating results of the execution of the classical-quantum hybrid program.

Abstract: The disclosure describes various aspects related to enabling effective multi-qubit operations, and more specifically, to techniques for enabling parallel multi-qubit operations on a universal ion trap quantum computer. In an aspect, a method of performing quantum operations in an ion trap quantum computer or trapped-ion quantum system includes implementing at least two parallel gates of a quantum circuit, each of the at least two parallel gates is a multi-qubit gate, each of the at least two parallel gates is implemented using a different set of ions of a plurality of ions in a ion trap, and the plurality of ions includes four or more ions. The method further includes simultaneously performing operations on the at least two parallel gates as part of the quantum operations. A trapped-ion quantum system and a computer-readable storage medium corresponding to the method described above are also disclosed.

Abstract: Aspects of the present disclosure relate generally to systems and methods for use in the implementation and/or operation of quantum information processing (QIP) systems, and more particularly, to the correction of light-shift effects in trapped-ion quantum gates. Techniques are described for light-shift correction of single qubit gates when the gates are implemented using counter-propagating Raman laser beams and when the gates are implemented using co-propagating Raman laser beams. Moreover, techniques are also described for light-shift correction of two-qubit gates.

Abstract: Systems and techniques are provided for a port server for heterogeneous hardware. A port server may include computing devices that may include multiple connection types. Storage devices may be connected to the computing devices. The computing devices may receive a communication from an external computing device intended for a hardware device of a heterogenous system over one of the connection types. The communication may be sent to the hardware device of the heterogenous system using one of the connection types. A response may be received from the hardware device of the heterogenous system over the connection type used to send the communication to the hardware device. The response from the hardware device of the heterogenous system may be sent to the external computing device over the connection type over which the communication was received from the external computing device.