Abstract: The disclosure describes various aspects of different for automated testing of optical assemblies. A system is described that includes an arm (e.g., a motorized arm) configured to be positioned over an optical assembly having a base plate with multiple optical elements that form one or more optical beam paths. The system also includes at least one optical tool that is configured to be removably attached to the arm and has a measurement instrument to perform a specified test on at least one of the optical beam paths. The arm is configured to adjust its position over the optical assembly to move the optical tool to the correct place to perform the specified test. The system may also include an optical tool changer configured to hold the optical tool in a tool holder when not attached to the arm and to hold additional optical tools in respective tool holders.

Abstract: Aspects of the present disclosure describe techniques for fast cooling of ion motion in a long chain using local motional modes. For example, a method is described for cooling down ions in a chain of ions that includes performing a cooling down sequence in which phonons are removed from the ions in the chain of ions by exciting and de-exciting local motional modes associated with individual ions, wherein sideband transitions that are part of the cooling down sequence are driven faster for the local motional modes than for collective motional modes for the same chain of ions; and completing the cooling down sequence when the local motional modes reach a ground state. A corresponding system and computer-readable storage medium for fast cooling of ion motion in a long chain using local motional modes are also described.

Abstract: The disclosure describes various aspects of a system with scalable and programmable coherent waveform generators. A network and digital-to-analog conversion (DAC) cards used by the network are described where each DAC card has a clock divider/replicator device with an input SYNC pin, a digital logic component, and one or more DAC components, and each output of the DAC components is used to control optical beams for a separate qubit of a quantum information processing (QIP) system. The network also includes a first distribution network to provide a clock signal to the clock divider/replicator device in the DAC cards, and a second distribution network to provide a start signal to the DAC cards, where the start signal is used by the digital logic component in the DAC card to assert the input SYNC pin when the start signal is asserted unless it is masked by the digital logic component.

Abstract: The disclosure describes various techniques to control of small angle Mølmer-Sørensen (MS) gates and to handle asymmetric errors. A technique is described for handling asymmetric errors in quantum information processing (QIP) systems. An exemplary method includes implementing a quantum circuit in the QIP system that has first and second qubit lines, with a first qubit state having a greater measurement error than a second qubit state; swapping the roles of the first and second qubit states at a quantum circuit level in response to at least one of the first qubit line and the second qubit line being expected to be at the first qubit state at a measurement; and enabling a quantum simulation using the quantum circuit with the first and second qubit states reassigned in at least one of the first qubit line and the second qubit line after the swapping of the respective roles.

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: The disclosure describes various aspects of a vibrationally isolated cryogenic shield for local high-quality vacuum. More specifically, the disclosure describes a cryogenic vacuum system replicated in a small volume in a mostly room temperature ultra-high vacuum (UHV) system by capping the volume with a suspended cryogenic cold finger coated with a high surface area sorption material to produce a localized extreme high vacuum (XHV) or near-XHV region. The system is designed to ensure that all paths from outgassing materials to the control volume, including multiple bounce paths off other warm surfaces, require at least one bounce off of the high surface area sorption material on the cold finger. The outgassing materials can therefore be pumped before reaching the control volume. To minimize vibrations, the cold finger is only loosely, mechanically connected to the rest of the chamber, and the isolated along with the cryogenic system via soft vacuum bellows.

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: 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 method of determining a pattern in a sequence of bits using a quantum computing system includes setting a first register of a quantum processor in a superposition of a plurality of string index states, encoding a bit string in a second register of the quantum processor, encoding a bit pattern in a third register of the quantum processor, circularly shifting qubits of the second register conditioned on the first register, amplifying an amplitude of a state combined with the first register in which the circularly shifted qubits of the second register matches qubits of the third register, measuring an amplitude of the first register and determining a string index state of the plurality of string index states associated with the amplified state, and outputting, by use of a classical computer, a string index associated with the first register in the measured state.

Abstract: The disclosure describes various aspects of techniques for optimal fault-tolerant implementations of controlled-Za gates and Heisenberg interactions. Improvements in the implementation of the controlled-Za gate can be made by using a clean ancilla and in-circuit measurement. Various examples are described that depend on whether the implementation is with or without measurement and feedforward. The implementation of the Heisenberg interaction can leverage the improved controlled-Za gate implementation. These implementations can cut down significantly the implementation costs associated with fault-tolerant quantum computing systems.

Abstract: Aspects of the present disclosure describe techniques for using a parabolic Cassegrain-type reflector for ablation. For example, a system for ablation loading of a trap is described that includes a reflector having a hole aligned with a loading aperture of the trap, and an atomic source positioned at a focal point of the reflector, where one or more laser beams are reflected from a reflective front side of the reflector and focused on a surface of the atomic source to produce an atomic plume, and the atomic plume once produced passing through the hole in the reflector and through a loading aperture of the trap for loading the trap. A method for ablation loading of a trap within a chamber in a trapped ion system is also described.

Abstract: Technologies are described herein to implement an optimizer that receives portions of a quantum circuit; identifies, from within the received portions of the quantum circuit, a pattern of quantum gates to perform a quantum function; searches a library for a replacement pattern of quantum gates, which is also to perform the quantum function, for the identified pattern of quantum gates; determines that a quantum cost of the replacement pattern of quantum gates is lower than a quantum cost of the identified pattern of quantum gates; and replaces the identified pattern of quantum gates with the replacement pattern of quantum gates.

Abstract: As system is provided for performing a method of receiving a superposition state defined by a sum of a plurality of addends, wherein each addend of the plurality of addends is a product between a corresponding coefficient of a plurality of coefficients and a corresponding state of a plurality of states encoded with block unary encoding. The system may identify at least one error state, of the plurality of states, having a string value that is not a block unary code string of a set of block unary code strings. The system may compute an updated superposition state based on the plurality of states without the error state.

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: Aspects of the present disclosure describe an atomic oven including a cathode, an anode that comprises a source material, and a power supply that provides a voltage between the cathode and the anode, wherein applying the voltage causes multiple electrons from the cathode to ablate the source material from the anode or locally heat the anode to cause source material to evaporate from the anode and, in both case, to produce a stream of ablated or evaporated particles that passes through an opening in the cathode.

Abstract: The disclosure describes various aspects of techniques for cooling a chain of ions to near the combined ground state that does not grow with the number of ions in the chain. By addressing each ion individually and using each ion to cool a different motional mode, it is possible to cool the motional modes concurrently. In an example, a third of the total motional modes can be cooled at the same time. In an aspect, the techniques include generating a sideband cooling laser beam for each ion in the ion chain, concurrently cooling two or more motional modes associated with the ions in the ion chain using the respective sideband cooling laser beam until each of the two or more motional modes reaches a motional ground state, and performing a quantum computation using the ion chain after the two or more motional modes have reached the motional ground state.

Abstract: A method of performing a computation using a quantum computer includes generating a plurality of laser pulses used to be individually applied to each of a plurality of trapped ions that are aligned in a first direction, each of the trapped ions having two frequency-separated states defining a qubit, and applying the generated plurality of laser pulses to the plurality of trapped ions to perform simultaneous pair-wise entangling gate operations on the plurality of trapped ions. Generating the plurality of laser pulses includes adjusting an amplitude value and a detuning frequency value of each of the plurality of laser pulses based on values of pair-wise entanglement interaction in the plurality of trapped ions that is to be caused by the plurality of laser pulses.

Abstract: A method of performing simultaneous entangling gate operations in a trapped-ion quantum computer includes selecting a gate duration value and a detuning frequency of pulses to be individually applied to a plurality of participating ions in a chain of trapped ions to simultaneously entangle a plurality of pairs of ions among the plurality of participating ions by one or more predetermined values of entanglement interaction, determining amplitudes of the pulses, based on the selected gate duration value, the selected detuning frequency, and the frequencies of the motional modes of the chain of trapped ions, generating the pulses having the determined amplitudes, and applying the generated pulses to the plurality of participating ions for the selected gate duration value. Each of the trapped ions in the chain has two frequency-separated states defining a qubit, and motional modes of the chain of trapped ions each have a distinct frequency.

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: The disclosure describes various techniques to control of small angle Mølmer-Sørensen (MS) gates and to handle asymmetric errors. A technique is described that implements a two-qubit calibration circuit with two MS gates, where a parameter ? represents an amount of entanglement of the MS gate. The calibration circuit is run for several values of ? to measure observed parity signals that are direct measurements of the values of ?. Calibration information is generated that describes the relationship between ? and the parity signals, and such calibration information is then provided to arbitrarily calibrate one or more MS gates in a quantum simulation. Another technique is described for using the calibration information in quantum simulations, including for quantum chemistry simulations.