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: A laser system provides a system output signal and a monitor signal with a predetermined phase and/or frequency relationship to the system output signal. The monitor signal is combined with a reference frequency to yield an optical beat-note. A telecom optical transceiver (e.g., an SFP or an SFP+ module) is used to convert the optical beat-note to an analog electrical beat-note. The transceiver can extract received-power information from the analog electrical beat-note and digitize the analog electrical beat-note to yield a digital electrical beat-note. The digital electrical beat-note can be used to stabilize the laser and the system output signal by phase or offset locking.

Abstract: A method for forming one or more vacuum cells comprising a portion of a first and second substrate comprises: forming layers of a bonding material on first and second surfaces of the first substrate; creating one or more cutouts extending from the first surface to the second surface, wherein each cutout extends through the bonding material; aligning the second substrate to the first substrate; and bonding, the bonding comprising applying, with a bonding structure, a pressure to the bonding material between the first substrate and the second substrate, wherein the bonding structure is configured to prevent an electrical current from flowing from the bonding material on the first surface of the first substrate to the bonding material on the second surface of the first substrate, and applying, while the pressure is applied, a voltage between the bonding material on the first surface of the first substrate and the second substrate.

Abstract: A quantum-particle cell manufacturing process includes coating a substrate with transparent conductive oxide (TCO) such as indium tin oxide (ITO). Regions of the TCO are then transformed, e.g., by pulsed-laser annealing, to increase their resistivity. The annealed region then electrically isolates adjacent higher conductivity and lower resistivity regions, which can serve as field plates. At least one annealed region extends from the cell interior through a bond between the substrate and sidewalls and into the cell exterior so that adjacent unannealed regions can serve as independently controllable feedthroughs. The annealing does not significantly affect the TCO thickness so the bond between the substrate and the sidewall structure remains intact and the completed quantum particle cell can be hermetically sealed.

Abstract: Quantum state readout is achieved using four-wave mixing. A quantum-state carrier, e.g., a cesium 133 atom, is illuminated with a set of three wavelengths. In the event that the atom is in a first quantum state, e.g., an F=3 state of cesium 133, the illumination triggers emission in a first direction from the atom of a fourth wavelength due to four-wave mixing. Detection of the emission in the first direction thus indicates that the atom is in the first quantum state. In an embodiment, failure to detect an emission indicates the atom is in a second quantum state. In other embodiments, a second set of three wavelengths is used to provide a positive indication that the atom is in its second state, e.g., an F=4 state for cesium 133.

Abstract: When a molecule is lost from a site of a qubit array, the site can be identified as a “target” site. A target site can be reloaded by transporting a molecule from a reservoir at least two millimeters to the target site. Alternatively, in response to the identifying, a molecule that has been transferred from the reservoir to a qubit-array region including the qubit array can be transferred to the target site. Quantum-logic language (QLL) programs can continue qubit operations on the array during transfers from the reservoir to the qubit region. Such operations can also continue during transfer from within the qubit region to a target site; in some cases, these latter operations are limited to sections of the qubit array not including a target site.

Abstract: A radio frequency (RF) radiation detection system is described. The RF detection system includes a metallic vacuum cell including a dispenser chamber and an interaction chamber. The dispenser chamber is configured to retain a quantum particle source. The interaction chamber is communicatively coupled with the dispenser chamber. The interaction chamber has aperture(s) therein and is configured to support the RF radiation. RF radiation access window(s) are connected with and hermetically seal the aperture(s).

Abstract: A pulsed-laser applies short (e.g., less than 10 pico-seconds) pulses to modify quantum particle (e.g., alkali-metal and alkaline-earth-metal atoms) ultra-high vacuum (UHV) cells to bond, ablate, and/or chemically modify vacuum-facing surfaces of the cell. The pulses are generated outside the cell and are transmitted through a vacuum-boundary wall. In one example, one vacuum-boundary wall is first contact bonded to other vacuum boundary walls at a relatively low temperature (below 200° C.), sufficient to form a temporary hermetic seal. Pulsed laser bonding is used to reinforce the contact bonds, correcting defects and generally increasing the robustness of the seal. The pulses provide high peak power to ensure strong bonds, but low total heat so as to avoid heat damage to nearby cell components and to limit quantum-particle sorbtion to and into cell walls.

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: 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.