Abstract: Each atom in a population of atoms can be characterized by a probability density distribution (PDD). Using a shaken-lattice technique, each PDD is split into a pair of sub-PDDs. The sub-PDDs of a pair are propagated along different paths to a common endpoint of the paths, resulting in a matter-wave interference pattern that encodes a net phase between the paths, e.g., due to differential effects associated with a gravity gradient. The matter-wave interference pattern can be measured to yield a respective measurement for each atom. The measurements can be aggregated to yield a result distribution that can serve as a classical domain estimate of the quantum-domain matter-wave interference pattern, and thus of the gravity gradient. Other embodiments can determine gradients for other types of fields.

Abstract: Techniques are described for efficiently generating optical traps within a quantum information processor by resonantly enhancing optical trap light using an optical ring resonator. An optical ring resonator may effectively recycle optical trap light in a closed optical path, such that the optical trap light passes through a vacuum chamber many times, reinforcing the intensity of the optical traps. As such, a low power light source may be utilized to generate the optical traps. While such a light source may generate light with a power that is alone insufficient to produce the desired number of optical traps, the optical ring resonator reinforces the intensity of this light through repeated passes through the vacuum chamber, building up light of sufficient intensity to produce the desired number of optical traps in the vacuum chamber.

Abstract: Techniques are described for efficient calibration of control parameters of a quantum information processor. The techniques include executing a quantum circuit a plurality of times while varying the value of a control parameter that parameterizes the quantum circuit. The quantum circuit may include quantum gates and/or other operations that are expected to produce a particular result when the control parameter is properly calibrated. By varying the value of the control parameter between successive executions of the quantum circuit, a calibrated value of the control parameter may be determined. Control parameters may, for instance, have values associated with a particular qubit, or with a particular pair (or larger group) of qubits.

Abstract: A system including a magnetic coil and a coil driver is described. The magnetic coil has a parasitic capacitance. The coil driver is coupled with the magnetic coil. The coil driver includes a pulse generator and a switching module coupled with the pulse generator. The pulse generator provides a pulse train. The switching module receives the pulse train and provides a switched driving signal to the magnetic coil. The switched driving signal has a frequency not less than a parasitic capacitance frequency.

Abstract: A quantum computer system uses a network of Mach-Zehnder interferometers (MZIs) to route laser light to selected atoms of a quantum array. The MZI network is defined in a photonic integrated circuit (PIC), which also includes an array of optical gratings. A laser system generates the light, the electronically controlled MZI network routes the light to respective optical gratings. The optical gratings convert the light from the MZI network into beams to illuminate the respective atoms so as to conditionally change their quantum states. This routing process offers advantages of economy, scalability and reliability over alternatives approaches to optical control of quantum states.

Abstract: Techniques are described for deterministically returning Rydberg atoms from a Rydberg state to a ground state. These techniques allow for improved calibration of Rydberg excitations, and for detection of errors without the loss of atoms from traps described above. In particular, the techniques comprise applying a pulse to a Rydberg atom to transition the atom from a Rydberg state to a second state having a lower energy than the Rydberg state. These pulses, referred to here as “drain pulses,” are selected to produce the desired transition to the second state, referred to herein as a “drain state.” The drain state may be selected as a state that will decay, or which may be driven, to a ground state. Accordingly, the drain pulse provides a path for atoms to transition from a Rydberg state to a ground state.

Abstract: A vacuum system is described. The vacuum system includes a vacuum cell and an ion trap. The vacuum cell includes walls having an inner surface that form at least a portion of a vacuum chamber. At least a portion of the inner surface has a topography including structures therein. The structures include a getter material. The ion trap is within the vacuum chamber.

Abstract: Metamaterial optics are integrated with vacuum-boundary walls of ultra-high-vacuum (UHV) cells to manipulate light in a manner analogous to various bulk optical elements including lenses, mirrors, beam splitters, polarizers, waveplate, wave guides, frequency modulators, and amplitude modulators. For example, UHV cells can have metasurface lenses formed on interior and/or exterior surfaces on one or more of their vacuum-boundary walls. Each metasurface lens can include a plurality of mesas with the same height and various cross-sectional dimensions. The uses of metasurface lenses allows through-going laser beams to be expanded, collimated or focused without using bulky refractive optics. Each metasurface lens can be formed on a cell wall using photolithographic or other techniques.

Abstract: A probe laser beam causes molecules to transition from a ground state to an excited state. A control laser beam causes molecules in the excited state to transition to a laser-induced Rydberg state. Microwave lenses convert a microwave wavefront into respective microwave beams. The microwave beams are counter-propagated through molecules so as to create a microwave interference pattern of alternating maxima and minima. The microwave interference pattern is imposed on the probe beam as a probe transmission pattern. The propagation direction of the microwave wavefront can be determined from the translational position of the probe transmission pattern; the intensity of the microwave wavefront can be determined by the intensity difference between the minima and maxima of the probe transmission pattern.

Abstract: A drop-in multi-optics module for a quantum-particle (e.g., rubidium, cesium) cell provides for more convenient and cost-effective manufacture of such cells (including vacuum cells, cold/ultra-cold matter cells, vapor cells, and channel cells). In a 3D printing approach, a model of a frame augmented by buffer material is 3D printed. The buffer material is removed from the augmented frame to achieved desired dimensions with greater precision than could be achieved by 3D printing the frame directly. Optical and, in some cases, other components are attached to the frame to realize the multi-optics drop-in module. Alternatively, the module can be formed by cutting out portions of a metal sheet and then folding the resulting 2D preform.

Abstract: Metamaterial optics are integrated with vacuum-boundary walls of ultra-high-vacuum (UHV) cells to manipulate light in a manner analogous to various bulk optical elements including lenses, mirrors, beam splitters, polarizers, waveplate, wave guides, frequency modulators, and amplitude modulators. For example, UHV cells can have metasurface lenses formed on interior and/or exterior surfaces on one or more of their vacuum-boundary walls. Each metasurface lens can include a plurality of mesas with the same height and various cross-sectional dimensions. The uses of metasurface lenses allows through-going laser beams to be expanded, collimated or focused without using bulky refractive optics. Each metasurface lens can be formed on a cell wall using photolithographic or other techniques.

Abstract: A spectroscopy system is described. The spectroscopy system includes a cell, a photodiode, and mirrors. The cell has walls forming a chamber therein. The chamber is configured to receive laser signal(s) and retaining a vapor therein. The vapor fluoresces in response to the laser signal(s). The mirrors are configured to direct fluorescent light from the vapor toward the photodiode. In some embodiments, the spectroscopy system is incorporated with a photonic integrated circuit.

Abstract: Quantum-state readout for an atom is performed using stimulated emission, e.g., by illuminating the atoms with electromagnetic radiation (EMR) with wavelengths selected to stimulate photon emission from the atom. Such an emission can be stimulated using four-wave mixing, in this case, three illumination wavelengths are mixed to stimulate the emissions wavelength. The illumination wavelengths are detuned from nearby resonant wavelengths to avoid capture by an atom orbital, which would lead to spontaneous rather than stimulated emission. The stimulated emissions are directional facilitating capture of a strong signal. The illumination wavelengths can be selected to be in different directions from the emissions wavelength to minimize noise in the emissions detection. The net result is a high-signal-to-noise ratio detection signal and quantum-state readout.

Abstract: A method for determining transient stability of a power grid using qubits of a quantum computing system comprises: receiving input parameters associated with a portion of the power grid; preparing an initial quantum state based on the input parameters; determining a plurality of time evolution steps, where each time evolution step is associated with a different respective iteration of a plurality of iterations; applying, for each iteration, a first set of quantum gate operations (QGOs) to the qubits, wherein the first set of QGOs produces a quantum state based on a first evolution of the initial quantum state or a quantum state produced by a previous iteration, and a second set of QGOs to the qubits, wherein the second set of QGOs produces a quantum state based on a second evolution of the quantum state produced by the first set of QGOs of a respective iteration.

Abstract: Quantum computing results can be stored in a quantum array of quantum-state carriers (QSCs) which must be read out in a form accessible to the classical world. The quantum array can be divided into regions that can be read in parallel. Each region is illuminated one QSC (e.g., atom) at a time and any resulting emissions are detected to determine the quantum state of each QSC and thus the value represented by the QSC. Multi-pixel superpixels are examined in each detection image to determine whether or not a respective QSC emitted in response to illumination. The field of view for each superpixel exceeds the area of the respective QSC, providing tolerance for misalignment of the photodetector relative to the quantum array.

Abstract: In one aspect, a system comprises: a memory configured to store a plurality of data units; a plurality of data sources, where each data source is configured to provide a respective data unit; and a processor configured to: determine a plurality of periods where each period is associated with a respective event and each event is associated with a different respective data source, determine a plurality of adjusted periods, where each period is associated with a respective adjusted period, determine a respective order for each adjusted period, determine a number of adjusted periods associated with each order, determine a number of time slots for a lowest order of adjusted periods based on the number of adjusted periods within each of the orders, and determine a start time for each event based on the order of the event and the number of time slots for the lowest order of adjusted periods.

Abstract: A rubidium optical atomic clock uses a modulated 778 nanometer (nm) probe beam and its reflection to excite rubidium 87 atoms, some of which emit 758.8 nm fluorescence as they decay back to the ground state. A spectral filter rejects scatter of the 778 nm probe beams while transmitting the 775.8 nm fluorescence so that the latter can be detected with a high signal-to-noise ratio. Since the spectral filter is only acceptably effective at angles of incidence less than 8° from the perpendicular, the atoms are localized by a magneto-optical trap so that most of the atoms lie within a conical volume defined by the 8° angle so that the resulting fluorescence detection signal has a high signal-to-noise ratio. The fluorescence detection signal can be demodulated to provide an error signal from which desired adjustments to the oscillator frequency can be calculated.

Abstract: In the manufacture of a quantum cell, multi-finger jigs are used to hold precision masks flat during a photolithographic procedure and or to apply force uniformly over a bonding area during an anodic or other direct bonding procedure. The fingers of a jig are flexible that they can bend sufficiently independently of each other that one finger can accommodate a non-uniformity of a surface to be contacted by the jig so that other fingers remain in contact with other areas of the surface. The fingers can be defined by slits orthogonal to a perimeter of the jig.

Abstract: A system, method, or device for providing a vacuum cell comprising a conformal coating is disclosed. The system includes (i) a vacuum cell having at least one internal vacuum chamber, the vacuum cell being formed of at least one piece, and (ii) a conformal coating on the at least one internal vacuum chamber or surface of the vacuum cell, the conformal coating having fewer seams than a number of the at least one piece.

Abstract: A system including a vacuum cell, an ion pump, and a multi-layer magnetic shield is described. The vacuum cell includes a magnetic field-sensitive section, a pump section, and a channel section providing a vacuum conductance path between the magnetic field-sensitive section and the pump section. The ion pump is in the pump section. The multi-layer magnetic shield surrounds at least a portion of the ion pump. The multi-layer magnetic shield has a first layer and a second layer. The first layer is between the second layer and the ion pump. The first layer has a moderate relative magnetic permeability and a high saturation magnetization. The second layer has a high relative magnetic permeability and a moderate saturation magnetization.