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Applying machine learning optimization methods to the production of a quantum gasAug 22 2019We apply three machine learning strategies to optimize the atomic cooling processes utilized in the production of a Bose-Einstein condensate (BEC). For the first time, we optimize both laser cooling and evaporative cooling mechanisms simultaneously. We ... More

Variational spin-squeezing algorithms on programmable quantum sensorsAug 22 2019Arrays of atoms trapped in optical tweezers combine features of programmable analog quantum simulators with atomic quantum sensors. Here we propose variational quantum algorithms, tailored for tweezer arrays as programmable quantum sensors, capable of ... More

Laboratory Calibrations of Fe XII-XIV Line-Intensity Ratios for Electron Density DiagnosticsAug 21 2019We have used an electron beam ion trap to measure electron-density-diagnostic line-intensity ratios for extreme ultraviolet lines from F XII, XIII, and XIV at wavelengths of 185-205 255-276 Angstroms. These ratios can be used as density diagnostics for ... More

Electronic interaction of slow hydrogen and helium ions in the nickel-silicon systemAug 21 2019Electronic stopping cross sections (SCS) of nickel, silicon and nickel-silicon alloys for protons and helium (He) ions are studied in the regime of medium and low energy ion scattering, i.e., for ion energies in the range from 500 eV to 200 keV. For protons, ... More

Control of resonant ionization as a function of time delay between two XUV few-femtosecond pulses. Quantitative application to heliumAug 20 2019It is shown that it is feasible to use ultrashort time delay between two XUV femtosecond pulses in order to control two photon resonant ionization. The proposal is demonstrated on the spectrum of Helium, in terms of nonperturbative solutions of the time ... More

Interactions and charge transfer dynamics of an Al$^+$ ion immersed in ultracold Rb and Sr atomsAug 20 2019Atomic clocks based on an Al$^+$ ion sympathetically cooled by a laser-cooled alkaline-earth ion have achieved unprecedented accuracy. Here, we investigate theoretically interactions and charge transfer dynamics of an Al$^+$ ion immersed in an ultracold ... More

Mercury Hydroxide as a Promising Triatomic Molecule to Probe P,T-odd InteractionsAug 20 2019In the quest to find a favourable triatomic molecule for detecting electric dipole moment of an electron (eEDM), we identify mercury hydroxide (HgOH) as an extremely attractive candidate from both experimental and theoretical viewpoints. Our calculations ... More

Wavelength-scale errors in optical localization due to spin-orbit coupling of lightAug 20 2019The precise determination of the position of point-like emitters and scatterers using far-field optical imaging techniques is of utmost importance for a wide range of applications in medicine, biology, astronomy, and physics. Although the optical wavelength ... More

Experimental demonstration of Cavity-Free Optical Isolators and Optical CirculatorsAug 20 2019Cavity free optical non reciprocity components, which have an inherent strong asymmetric interaction between their co and counter propagation direction, are key to produce such as optical isolators and circulators. According to the proposal presented ... More

Post-Newtonian Hamiltonian description of an atom in a weak gravitational fieldAug 19 2019We extend the systematic calculation of an approximately relativistic Hamiltonian for centre of mass and internal dynamics of an electromagnetically bound two-particle system by Sonnleitner and Barnett [1] to the case including a weak post-Newtonian gravitational ... More

Dynamic characterization of an alkali-ion battery as a source for laser-cooled atomsAug 19 2019We investigate a solid-state, reversible, alkali-ion battery (AIB) capable of regulating the density of alkali atoms in a vacuum system used for the production of laser-cooled atoms. The cold-atom sample can be used with in-vacuum chronoamperometry as ... More

Performance analysis of an optically pumped magnetometer in Earth's magnetic fieldAug 19 2019We experimentally investigate the influence of the orientation of optically pumped magnetometers in Earth's magnetic field. We focus our analysis to an operational mode that promises femtotesla field resolu-tions at such field strengths. For this so-called ... More

Exact annihilation energy and proper decay time solution of a para-positronium systemAug 17 2019Para positronium composed by an electron-antielectron pair is an unstable system decaying into two high energetic gamma photons via self annihilation process, due to the conservation of the charge conjugation parity in electromagnetically interacting ... More

Enhancing frustrated double ionisation with no electronic correlation in triatomic molecules using counter-rotating two-color circular laser fieldsAug 17 2019We demonstrate significant enhancement of frustrated double ionization (FDI) in the two-electron triatomic molecule D$_{3}^{+}$ when driven by counter-rotating two-color circular (CRTC) laser fields. We employ a three-dimensional semiclassical model that ... More

Rydberg mediated entanglement in a two-dimensional neutral atom qubit arrayAug 16 2019We demonstrate high fidelity two-qubit Rydberg blockade and entanglement in a two-dimensional qubit array. The qubit array is defined by a grid of blue detuned lines of light with 121 sites for trapping atomic qubits. Improved experimental methods have ... More

Dynamics of Hot Bose-Einstein Condensates: stochastic Ehrenfest relations for number and energy dampingAug 16 2019Describing high-temperature Bose gases poses a long-standing theoretical challenge. We present exact stochastic Ehrenfest relations for the stochastic projected Gross-Pitaevskii equation, including both number and energy damping mechanisms, and all projector ... More

An atomic array optical clock with single-atom readoutAug 15 2019Measuring time is central to all sciences. Currently, the most accurate and stable clocks are based on optical interrogation of either a single ion or an ensemble of neutral atoms confined in an optical lattice. Here we demonstrate a new optical clock ... More

Quantum optics with single spinsAug 15 2019Defects in solids are in many ways analogous to trapped atoms or molecules. They can serve as long-lived quantum memories and efficient light-matter interfaces. As such, they are leading building blocks for long-distance quantum networks and distributed ... More

Observation of Dynamical FermionizationAug 14 2019We observe dynamical fermionization, where the momentum distribution of a Tonks-Girardeau (T-G) gas of strongly interacting bosons in 1D evolves from bosonic to fermionic after its axial confinement is removed. The asymptotic momentum distribution after ... More

Photon scattering from a cold, Gaussian atom cloudAug 14 2019We study the effect of a weakly driven atomic cloud's polarization distribution on its photon scattering lineshape. In doing this, we find three distinct polarization regimes. First, for dilute clouds, the polarization magnitude is relatively constant. ... More

Near L-edge photoionization of triply charged iron ionsAug 14 2019Relative cross sections for $m$-fold photoionization ($m=1,\ldots,5$) of Fe$^{3+}$ by single photon absorption were measured employing the photon-ion merged-beams setup PIPE at the PETRA III synchrotron light source operated at DESY in Hamburg, Germany. ... More

Spin State Dynamics in a Bichromatic Microwave Field: Power Narrowing and Broadening of a Magnetic ResonanceAug 14 2019Driving an open spin system by two strong, nearly degenerate fields enables addressing populations of individual spin states, characterisation of their interaction with thermal bath, and measurements of their relaxation/decoherence rates. With such addressing ... More

Quantum trajectories in spin-exchange collisions reveal the nature of spin-noise correlations in multi-species alkali vaporsAug 14 2019Aug 15 2019Spin-exchange collisions in alkali vapors have been at the basis of several fundamental and applied investigations, like nuclear structure studies and tests of fundamental symmetries, ultra-sensitive atomic magnetometers, magnetic resonance and bio-magnetic ... More

Quantum trajectories in spin-exchange collisions reveal the nature of spin-noise correlations in multi-species alkali vaporsAug 14 2019Spin-exchange collisions in alkali vapors have been at the basis of several fundamental and applied investigations, like nuclear structure studies and tests of fundamental symmetries, ultra-sensitive atomic magnetometers, magnetic resonance and bio-magnetic ... More

Molecular dissociation in few-cycle laser pulses: From attosecond to femtosecond pulse durationAug 13 2019The dissociation dynamics of diatomic molecules interacting with (near) optical laser pulses of different duration is investigated by an elaborate discussion of the electric field of the laser and by a direct solution of the time-dependent molecular Schr\"odinger ... More

High-precision ab initio calculations of the spectrum of Lr$^{+}$Aug 13 2019The planned measurement of optical resonances in singly-ionised lawrencium (Z = 103) requires accurate theoretical predictions to narrow the search window. We present high-precision, ab initio calculations of the electronic spectra of Lr$^+$ and its lighter ... More

Entanglement balance of quantum $(e,2e)$ scattering processesAug 13 2019The theory of quantum information constitutes the functional value of the quantum entanglement, i.e., quantum entanglement is essential for high fidelity of quantum protocols, while fundamental physical processes behind the formation of quantum entanglement ... More

Relativistic many body theory of the electric dipole moment of $^{129}$Xe and its implications for probing new physics beyond the Standard ModelAug 12 2019We report the results of our theoretical studies of the time-reversal and parity violating electric dipole moment (EDM) of $^{129}$Xe arising from the nuclear Schiff moment (NSM) and the electron-nucleus tensor-pseudotensor (T-PT) interaction based on ... More

T^3-Stern-Gerlach Matter-Wave InterferometerAug 11 2019We present a unique matter-wave interferometer whose phase scales with the cube of the time the atom spends in the interferometer. Our scheme is based on a full-loop Stern-Gerlach interferometer incorporating four magnetic field gradient pulses to create ... More

Holographic detection of parity in atomic and molecular orbitalsAug 11 2019We report on comparative and differential measurements on strong-field ionization of N2 molecules and their companion atoms of Ar. Photoelectron holography patterns such as the carpet-like and the fan-shaped structures are found to be dephased for both ... More

Analysis of Electric Dipole Moment of $^{225}$Ra Atom using the Relativistic Normal Coupled-cluster TheoryAug 10 2019In view of the large differences in the previous calculations of enhancement factors to the parity and time-reversal violating (P,T-odd) electric dipole moment (EDM) of $^{225}$Ra due to nuclear Schiff moment (NSM) and tensor-pseudotensor (T-PT) electron-nucleus ... More

Multiconfigurational time-dependent Hartree approaches for indistinguishable particlesAug 09 2019In this Colloquium, the wavefunction-based Multiconfigurational Time-Dependent Hartree approaches to the dynamics of indistinguishable particles (MCTDH-F for Fermions and MCTDH-B for Bosons) are reviewed. MCTDH-B and MCTDH-F or, together, MCTDH-X are ... More

Hyperfine constants and line separations for the $^{1}S_{0}-\,^{3}P_{1}$ intercombination line in neutral ytterbium with sub-Doppler resolutionAug 09 2019Optical frequency measurements of the intercombination line $(6s^{2})\,^{1}S_{0} -(6s6p)\,^{3}P_{1}$ in the isotopes of ytterbium are carried out with the use of sub-Doppler fluorescence spectroscopy on an atomic beam. A dispersive signal is generated ... More

Applying matched-filter technique to the search for dark matter transients with networks of quantum sensorsAug 09 2019There are several networks of precision sensors in existence, including networks of atomic clocks, magnetometers, and gravitational wave detectors. These networks can be re-purposed for searches of exotic physics, such as direct dark matter searches. ... More

Real-time observation of single atoms trapped and interfaced to a nanofiber cavityAug 09 2019We demonstrate an optical tweezer based single atom trapping on an optical nanofiber cavity. We show that the fluorescence of single atoms trapped on the nanofiber cavity can be readily observed in real-time through the fiber guided modes. The photon ... More

Towards analog quantum simulations of lattice gauge theories with trapped ionsAug 08 2019Gauge field theories play a central role in modern physics and are at the heart of the Standard Model of elementary particles and interactions. Despite significant progress in applying classical computational techniques to simulate gauge theories, it ... More

UKRmol+: a suite for modelling of electronic processes in molecules interacting with electrons, positrons and photons using the R-matrix methodAug 08 2019UKRmol+ is a new implementation of the UK R-matrix electron-molecule scattering code. Key features of the implementation are the use of quantum chemistry codes such as Molpro to provide target molecular orbitals; the optional use of mixed Gaussian -- ... More

Singlet Pathway to the Ground State of Ultracold Polar MoleculesAug 07 2019Starting from weakly bound Feshbach molecules, we demonstrate a two-photon pathway to the dipolar ground state of bi-alkali molecules that involves only singlet-to-singlet optical transitions. This pathway eliminates the search for a suitable intermediate ... More

Purifying electron spectra from noisy pulses with machine learning using synthetic Hamilton matricesAug 07 2019Photo-electron spectra obtained with intense pulses generated by free-electron lasers through self-amplified spontaneous emission are intrinsically noisy and vary from shot to shot. We extract the purified spectrum, corresponding to a Fourier-limited ... More

Fully numerical calculations on atoms with fractional occupations. Range-separated exchange functionalsAug 07 2019A recently developed finite element approach for fully numerical atomic structure calculations [S. Lehtola, Int. J. Quantum Chem. e25945 (2019)] is extended to the treatment of atoms with spherically symmetric densities via fractional occupations. Specialized ... More

Numerical exploration of three relativistic particles in a finite volume including two-particle resonances and bound statesAug 07 2019In this work, we use an extension of the quantization condition, given in Ref. [1], to numerically explore the finite-volume spectrum of three relativistic particles, in the case that two-particle subsets are either resonant or bound. The original form ... More

A flexible, open-source radio-frequency driver for acousto-optic and electro-optic devicesAug 06 2019We present a design for a radio-frequency driver that leverages telecom amplifiers to achieve high power output and wide bandwidth. The design consists of two compact printed circuit boards (total area $< 255$ cm), which incorporate power (turn-on) and ... More

Roles of electron correlation effects for accurate determination of $g_j$ factors of low-lying states of $^{113}$Cd$^+$ and their applications to atomic clockAug 06 2019We investigate roles of electron correlation effects in the determination of $g_j$ factors of the $ns~^2S_{1/2}$ ($n$=5,6,7), $np~^2P_{1/2,3/2}$ ($n$=5,6), $5d~^2D_{3/2,5/2}$, and $4f~^2F_{5/2,7/2}$ states of the singly ionized cadmium (Cd$^+$) ion. Single ... More

Microwave shielding of ultracold polar molecules with imperfectly circular polarizationAug 05 2019We investigate the use of microwave radiation to produce a repulsive shield between pairs of ultracold polar molecules and prevent collisional losses that occur when molecular pairs reach short range. We carry out coupled-channels calculations on RbCs+RbCs ... More

Neutralization of slow helium ions scattered from single crystalline aluminum and tantalum surfaces and their oxidesAug 05 2019We investigated the impact of surface oxygen on the ion yield for He$^+$ ions scattered from different single crystalline surfaces in low-energy ion scattering. Initially clean Al(111) and Ta(111) were exposed to molecular oxygen and ion spectra for different ... More

Roadmap on STIRAP applicationsAug 05 2019STIRAP (Stimulated Raman Adiabatic Passage) is a powerful laser-based method, usually involving two photons, for efficient and selective transfer of population between quantum states. A particularly interesting feature is the fact that the coupling between ... More

Observation of the algebraic localization-delocalization transition in a 1D disordered potential with a bias forceAug 05 2019In a one-dimensional (1D) disordered potential, quantum interferences leading to Anderson lo-calization are ubiquitous, such that all wave-functions are exponentially localized. Moreover, no phase transition toward delocalization is expected in 1D. This ... More

Rydberg atom entanglements in the weak coupling regimeAug 05 2019We present an entanglement scheme for Rydberg atoms using the van der Waals interaction phase induced by Ramsey-type pulsed interactions. This scheme realizes not only controlled phase operations between atoms at a distance larger than Rydberg blockade ... More

Sub-millimetric ultra-low-field MRI detected in situ by a dressed atomic magnetometerAug 04 2019Magnetic Resonance Imaging (MRI) is universally acknowledged as an excellent tool to extract detailed spatial information with minimally invasive measurements. Efforts toward ultra-low-field (ULF) MRI are made to simplify the scanners and to reduce artefacts ... More

Impact of ion motion on atom-ion confinement-induced resonances in hybrid trapsAug 03 2019We investigate confinement-induced resonances in atom-ion quantum mixtures confined in hybrid traps. Specifically, we consider an ion confined in a time-dependent radio-frequency Paul trap with linear geometry, while the atom is constrained to move into ... More

Three-dimensional trapping of individual Rydberg atoms in ponderomotive bottle beam trapsAug 02 2019We demonstrate three-dimensional trapping of individual Rydberg atoms in holographic optical bottle beam traps. Starting with cold, ground-state $^{87}$Rb atoms held in standard optical tweezers, we excite them to $nS_{1/2}$, $nP_{1/2}$, or $nD_{3/2}$ ... More

Averaged electron densities of the helium-like atomsAug 02 2019Different kinds of averaging of the wavefunctions/densities of the two-electron atomic systems are investigated. Using the Pekeris-like method, the ground state wave functions $\Psi$ of the helium-like atoms with nucleus charge $1\leq Z\leq5$ are calculated ... More

AEDGE: Atomic Experiment for Dark Matter and Gravity Exploration in SpaceAug 02 2019We propose in this White Paper a concept for a space experiment using cold atoms to search for ultra-light dark matter, and to detect gravitational waves in the frequency range between the most sensitive ranges of LISA and the terrestrial LIGO/Virgo/KAGRA/INDIGO ... More

Engineering of Microfabricated Ion Traps and Integration of Advanced On-Chip FeaturesAug 01 2019Trapped atomic ions are a proven and powerful tool for the fundamental research of quantum physics. They have emerged in recent years as one of the most promising candidates for several practical technologies including quantum computers, quantum simulators, ... More

Engineering of Microfabricated Ion Traps and Integration of Advanced On-Chip FeaturesAug 01 2019Aug 06 2019Trapped atomic ions are a proven and powerful tool for the fundamental research of quantum physics. They have emerged in recent years as one of the most promising candidates for several practical technologies including quantum computers, quantum simulators, ... More

Direct Observation of Ultracold Bimolecular ReactionsJul 31 2019Chemical reactions result in the conversion of reactants to products through an intermediate state or a transition state. Unambiguous identifications of and investigations of chemical reactions are thus most complete when detecting all of the involved ... More

Density-based one-dimensional model potentials for strong-field simulations in $\text{He}$, $\text{H}_{2}^{+}$ and $\text{H}_{2}$Jul 31 2019We present results on the accurate one-dimensional (1D) modeling of simple atomic and molecular systems excited by strong laser fields. We use atomic model potentials that we derive from the corrections proposed earlier using the reduced ground state ... More

Detecting, tracking, and eliminating drift in quantum information processorsJul 31 2019If quantum information processors (QIPs) are ever to fulfill their potential, the diverse errors that impact them must be understood and suppressed. But errors fluctuate over time in most processors and the most widely used tools for characterizing them ... More

A new quantum clock for measuring photoemission delay timesJul 31 2019In photoionization, the extremely short delay between photon annihilation and electron emission is known as the Eisenbud-Wigner-Smith (EWS) delay, and is usually measured in attoseconds ($10^{-18}$ seconds). We present a new method for measuring this ... More

Measuring the time a tunnelling atom spends in the barrierJul 31 2019Tunnelling is one of the most paradigmatic and evocative phenomena of quantum physics, underlying processes such as photosynthesis and nuclear fusion, as well as devices ranging from SQUID magnetometers to superconducting qubits for quantum computers. ... More

Compensation of gravity on cold atoms by a linear optical potentialJul 31 2019We demonstrate gravity compensation for an ultracold gas of $^{87}$Rb atoms with a time-averaged optical potential. The position of a far-off-resonance beam is temporally modulated with an acousto-optic deflector to efficiently produce a potential with ... More

A pyramid MOT with integrated optical cavities as a cold atom platform for an optical lattice clockJul 31 2019We realize a two-stage, hexagonal pyramid magneto-optical trap (MOT) with strontium, and demonstrate loading of cold atoms into cavity-enhanced 1D and 2D optical lattice traps, all within a single compact assembly of in-vacuum optics. We show that the ... More

Ultralong-range Rydberg moleculesJul 31 2019We review ultralong-range Rydberg molecules (ULRM), which are bound states between a Rydberg atom and one or more ground-state atoms with bond lengths on the order of thousands of Bohr radii. The binding originates from multiple electron-atom scattering ... More

Deterministic facilitated excitation of the weakly-driven atom in heteronuclear Rydberg atom pairs beyond antiblockadeJul 31 2019Due to the intrinsic strong blockaded interaction shifting the energy level of Rydberg state, the steady Rydberg probability may be substantially restrained to a low level, especially for atoms suffering from weak drivings. We report an exotic excitation ... More

High fidelity manipulation of a qubit built from a synthetic nucleusJul 31 2019The recently demonstrated trapping and laser cooling of $^{133}$Ba$^+$ has opened the door to the use of this nearly ideal atom for quantum information processing. However, before high fidelity qubit operations can be performed, a number of unknown state ... More

Microwave spectroscopy of the $1\mathrm{s}n\mathrm{p}\,^3\mathrm{P}_J$ fine structure of high Rydberg states in $^4$HeJul 30 2019The $1\mathrm{s}n\mathrm{p}\,^3\mathrm{P}_J$ fine structure of high Rydberg states in helium has been measured by microwave spectroscopy of single-photon transitions from $1\mathrm{s}n\mathrm{s}\,^3\mathrm{S}_1$ levels in pulsed supersonic beams. For ... More

A Three-step Model of High Harmonic Generation using Complex Classical TrajectoriesJul 30 2019We present a new trajectory formulation of high harmonic generation that treats classically allowed and classically forbidden processes within a single dynamical framework. Complex trajectories orbit the nucleus, producing the stationary Coulomb ground ... More

Effect of ion-trap parameters on energy distributions of ultra-cold atom-ion mixturesJul 30 2019The holy grail of ion-neutral systems is reaching the s-wave scattering regime. However, most of these systems have a fundamental lower collision energy limit which is higher than this s-wave regime. This limit arises from the time-dependant trapping ... More

Revealing Energy Dependence of Quantum Defects via Two Heteronuclear Atoms in an Optical TweezerJul 30 2019As a physically motivated and computationally simple model for cold atomic and molecular collisions, the multichannel quantum defect theory (MQDT) with frame transformation (FT) formalism provides an analytical treatment of scattering resonances in an ... More

Balanced Coherence Times of Mixed-Species Atomic Qubits in a Dual $3\times3$ Magic-Intensity Optical Dipole Trap ArrayJul 30 2019In this work, we construct a polarization-mediated magic-intensity (MI) optical dipole trap (ODT) array, in which the detrimental effects of light shifts on the mixed-species qubits are efficiently mitigated so that the coherence times of the mixed-species ... More

Imaging Nematic Transitions in Iron-Pnictide Superconductors with a Quantum GasJul 29 2019The SQCRAMscope is a recently realized Scanning Quantum CRyogenic Atom Microscope that utilizes an atomic Bose-Einstein condensate to measure magnetic fields emanating from solid-state samples. The quantum sensor does so with unprecedented DC sensitivity ... More

LIght scalars with lepton number to solve the $(g-2)_e$ anomalyJul 29 2019Scalars that carry lepton number can help mediate would-be lepton-number-violating processes, such as neutrinoless double $\beta$ decay or lepton-scattering-mediated nucleon-antinucleon conversion. Here we show that such new scalars can also solve the ... More

LIght scalars with lepton number to solve the $(g-2)_e$ anomalyJul 29 2019Aug 11 2019Scalars that carry lepton number can help mediate would-be lepton-number-violating processes, such as neutrinoless double $\beta$ decay or lepton-scattering-mediated nucleon-antinucleon conversion. Here we show that such new scalars can also solve the ... More

Observation of Townes solitons in two-dimensional Bose gasesJul 29 2019New length scales often emerge in many-body systems driven out of equilibrium, leading to further development of delicate many-body states. Modulational instability, and the accompanying formation of solitons, is one important example. Here we report ... More

Quantum bridges in phase space: Interference and nonclassicality in strong-field enhanced ionisationJul 29 2019We perform a phase-space analysis of strong-field enhanced ionisation in molecules, with emphasis on quantum-interference effects. Using Wigner quasi-probability distributions and the quantum Liouville equation, we show that the momentum gates reported ... More

Photoionization of tungsten ions: experiment and theory for W$^{5+}$Jul 29 2019Experimental and theoretical cross sections are reported for single-photon single ionization of W$^{5+}$ ions. Absolute measurements were conducted employing the photon-ion merged-beams technique. Detailed photon-energy scans were performed at (67$\pm$10)~meV ... More

Photoionization of tungsten ions: experiment and theory for W$^{5+}$Jul 29 2019Aug 03 2019Experimental and theoretical cross sections are reported for single-photon single ionization of W$^{5+}$ ions. Absolute measurements were conducted employing the photon-ion merged-beams technique. Detailed photon-energy scans were performed at (67$\pm$10)~meV ... More

The Nested_fit data analysis programJul 29 2019We present here Nested_fit, a Bayesian data analysis code developed for investigations of atomic spectra and other physical data. It is based on the nested sampling algorithm with the implementation of an upgraded lawn mower robot method for finding new ... More

Modular Quantum Computation in a Trapped Ion SystemJul 29 2019Modern computation relies crucially on modular architectures, breaking a complex algorithm into self-contained subroutines. A client can then call upon a remote server to implement parts of the computation independently via an application programming ... More

Application of the Hylleraas-$B$-spline basis set: Nonrelativistic Bethe logarithm of heliumJul 27 2019In this work, we report an application of Hylleraas-$B$-spline basis set to the nonrelativistic Bethe logarithm calculation of helium. The Bethe logarithm for $n\ ^1S$, $n$ up to 10, states of helium are calculated with a precision of 7-9 significant ... More

Testing the Robustness of Robust Phase EstimationJul 26 2019The Robust Phase Estimation (RPE) protocol was designed to be an efficient and robust way to calibrate quantum operations. The robustness of RPE refers to its ability to estimate a single parameter, usually gate amplitude, even when other parameters are ... More

Testing the Robustness of Robust Phase EstimationJul 26 2019Aug 01 2019The Robust Phase Estimation (RPE) protocol was designed to be an efficient and robust way to calibrate quantum operations. The robustness of RPE refers to its ability to estimate a single parameter, usually gate amplitude, even when other parameters are ... More

$\mathcal{P}$,$\mathcal{T}$-odd Faraday rotation on atoms and molecules in intra-cavity absorption spectroscopy as an alternative way to search for the $\mathcal{P}$,$\mathcal{T}$-odd effects in natureJul 26 2019Present limit on the electron electric dipole moment ($e$EDM) is based on the electron spin precession measurement. We propose an alternative approach - observation of the $\mathcal{P}$,$\mathcal{T}$-odd Faraday effect in an external electric field on ... More

Engineering non-binary Rydberg interactions via electron-phonon couplingJul 26 2019Coupling electronic and vibrational degrees of freedom of Rydberg atoms held in optical tweezers arrays offers a flexible mechanism for creating and controlling atom-atom interactions. We find that the state-dependent coupling between Rydberg atoms and ... More

Multichannel interactions of two atoms in an optical tweezerJul 25 2019The multichannel Na-Cs interactions are characterized by a series of measurements using two atoms in an optical tweezer, along with a multichannel quantum defect theory (MQDT). The triplet and singlet scattering lengths are measured by performing Raman ... More

Nondestructive cooling of an atomic quantum register via state-insensitive Rydberg interactionsJul 25 2019Jul 28 2019We propose a protocol for sympathetically cooling neutral atoms without destroying the quantum information stored in their internal states. This is achieved by designing state-insensitive Rydberg interactions between the data-carrying atoms and cold auxiliary ... More

Nondestructive cooling of an atomic quantum register via state-insensitive Rydberg interactionsJul 25 2019We propose a protocol for sympathetically cooling neutral atoms without destroying the quantum information stored in their internal states. This is achieved by designing state-insensitive Rydberg interactions between the data-carrying atoms and cold auxiliary ... More

Generalized Hyper-Ramsey spectroscopy in an optically dense mediumJul 25 2019In this work, the peculiarities of Ramsey resonance and its sensitivity to the light shift from an optically dense medium of cold atoms are investigated. We considered different composite pulse protocols for clock spectroscopy such as hyper-Ramsey, modified ... More

Buffer gas cooling of a trapped ion to the quantum regimeJul 25 2019Great advances in precision quantum measurement have been achieved with trapped ions and atomic gases at the lowest possible temperatures. These successes have inspired ideas to merge the two systems. In this way one can study the unique properties of ... More

Extended calculations of energy levels, radiative properties, and lifetimes for oxygen-like Mo XXXVJul 25 2019Employing two state-of-the-art methods, second-order many-body perturbation theory and multiconfiguration Dirac-Fock, highly accurate calculations are performed for the lowest 318 fine-structure levels arising from the $2s^{2} 2p^{4}$, $2s 2p^{5}$, $2p^{6}$, ... More

Frequency Shifts due to Stark Effects on a Rb two-photon transitionJul 25 2019The $5S_{1/2}\rightarrow 5D_{5/2}$ two-photon transition in Rb is of interest for the development of a compact optical atomic clock. Here we present a rigorous calculation of the 778.1~nm ac-Stark shift ($2.30(4) \times10^{-13}$(mW/mm$^2$)$^{-1}$) that ... More

Generation of cold Rydberg atoms at submicron distances from an optical nanofiberJul 25 2019We report on a highly controllable, hybrid quantum system consisting of cold Rydberg atoms and an optical nanofiber interface. Using a two-photon excitation process to drive $5S \rightarrow 5P \rightarrow 29D $ transitions in $^{87}$Rb, we observe both ... More

Generation of cold Rydberg atoms at submicron distances from an optical nanofiberJul 25 2019Aug 01 2019We report on a highly controllable, hybrid quantum system consisting of cold Rydberg atoms and an optical nanofiber interface. Using a two-photon ladder-type excitation in $^{87}$Rb, we demonstrate both coherent and incoherent Rydberg excitation at submicron ... More

Status and Prospects for CPT Tests with the ALPHA ExperimentJul 24 2019A primary goal of the ALPHA experiment at CERN is to perform precise tests of CPT symmetry. Here, we report on the significant progress made in recent years on antihydrogen spectroscopy and the outlook for the future.

Time delays in ultracold atomic and molecular collisionsJul 24 2019We study the behavior of the Eisenbud-Wigner collisional time delay around Feshbach resonances in cold and ultracold atomic and molecular collisions. We carry out coupled-channels scattering calculations on ultracold Rb and Cs collisions. In the low-energy ... More

Sr atom interferometry with the optical clock transition as a gravimeter and a gravity gradiometerJul 24 2019We characterize the performance of a gravimeter and a gravity gradiometer based on the $^{1}$S$_{0}$-$^3$P$_0$ clock transition of strontium atoms. We use this new quantum sensor to measure the gravitational acceleration with a relative sensitivity of ... More

(py)LIon: a package for simulating trapped ion trajectoriesJul 24 2019The (py)LIon package is a set of tools to simulate the classical trajectories of ensembles of ions in electrodynamic traps. Molecular dynamics simulations are performed using LAMMPS, an efficient and feature-rich program. (py)LIon has been validated by ... More

A hybrid ion-atom trap with integrated high resolution mass spectrometerJul 24 2019In this article we describe the design, construction and implementation of our ion-atom hybrid system incorporating a high resolution time of flight mass spectrometer (TOFMS). Potassium atoms ($^{39}$K) in a Magneto Optical Trap (MOT) and laser cooled ... More

Toolbox approach for quasi-relativistic calculation of molecular properties for precision tests of fundamental physicsJul 24 2019A generally applicable approach for the calculation of relativistic one-electron properties with two-component wave functions is presented. The formalism is explicitly evaluated for the example of quasi-relativistic wavefunctions obtained within the zeroth ... More

Ab initio Study of Ground-State CS Photodissociation Via Highly Excited Electronic StatesJul 24 2019Photodissociation by ultraviolet radiation is the key destruction pathway for CS in photon-dominated regions, such as diffuse clouds. However, the large uncertainties of photodissociation cross sections and rates of CS, resulting from a lack of both laboratory ... More