Atomic Physics

---

ZAIGA: Zhaoshan Long-baseline Atom Interferometer Gravitation Antenna (1903.09288v2)

Ming-Sheng Zhan, Jin Wang, Wei-Tou Ni, Dong-Feng Gao, Gang Wang, Ling-Xiang He, Run-Bing Li, Lin Zhou, Xi Chen, Jia-Qi Zhong, Biao Tang, Zhan-Wei Yao, Lei Zhu, Zong-Yuan Xiong, Si-Bin Lu, Geng-Hua Yu, Qun-Feng Cheng, Min Liu, Yu-Rong Liang, Peng Xu, Xiao-Dong He, Min Ke, Zheng Tan, Jun Luo

2019-03-22

The Zhaoshan long-baseline Atom Interferometer Gravitation Antenna (ZAIGA) is a new type of underground laser-linked interferometer facility, and is currently under construction. It is in the 200-meter-on-average underground of a mountain named Zhaoshan which is about 80 km southeast to Wuhan. ZAIGA will be equipped with long-baseline atom interferometers, high-precision atom clocks, and large-scale gyros. ZAIGA facility will take an equilateral triangle configuration with two 1-km-apart atom interferometers in each arm, a 300-meter vertical tunnel with atom fountain and atom clocks mounted, and a tracking-and-ranging 1-km-arm-length prototype with lattice optical clocks linked by locked lasers. The ZAIGA facility will be used for experimental research on gravitation and related problems including gravitational wave detection, high-precision test of the equivalence principle of micro-particles, clock based gravitational red-shift measurement, rotation measurement and gravito-magnetic effect.

Non-adiabatic Storage of Short Light Pulses in an Atom-Cavity System (1903.10922v1)

Tobias Macha, Eduardo Uruñuela, Wolfgang Alt, Maximilian Ammenwerth, Deepak Pandey, Hannes Pfeifer, Dieter Meschede

2019-03-26

We demonstrate the storage of ~ns light pulses in an intrinsically fiber-coupled atomic memory. Our storage protocol addresses a regime beyond the conventional adiabatic limit, for which we extract the optimal control laser pulse properties from a numerical simulation of our system. We measure storage efficiencies of , in close agreement with the maximum expected efficiency. Such well-controlled and high-bandwidth atom-photon interfaces are an attractive technology for future hybrid quantum networks.

Single-beam Zeeman slower and magneto-optical trap using a nanofabricated grating (1811.09180v2)

D. S. Barker, E. B. Norrgard, N. N. Klimov, J. A. Fedchak, J. Scherschligt, S. Eckel

2018-11-22

We demonstrate a compact (0.25 L) system for laser cooling and trapping atoms from a heated dispenser source. Our system uses a nanofabricated diffraction grating to generate a magneto-optical trap (MOT) using a single input laser beam. An aperture in the grating allows atoms from the dispenser to be loaded from behind the chip, increasing the interaction distance of atoms with the cooling light. To take full advantage of this increased distance, we extend the magnetic field gradient of the MOT to create a Zeeman slower. The MOT traps approximately Li atoms emitted from an effusive source with loading rates in excess of s. Our design is portable to a variety of atomic and molecular species and could be a principal component of miniaturized cold-atom-based technologies.

Application of the time-dependent surface flux method to the time-dependent multiconfiguration self-consistent-field method (1903.10743v1)

Yuki Orimo, Takeshi Sato, Kenichi L. Ishikawa

2019-03-26

We present a numerical implementation of the time-dependent surface flux (tSURFF) method [New J. Phys. 14, 013021 (2012)], an efficient computational scheme to extract photoelectron energy spectra, to the time-dependent multiconfiguration self-consistent-field (TD-MCSCF) method. Extending the original tSURFF method developed for single particle systems, we formulate the equations of motion for the spectral amplitude of orbital functions constutiting the TD-MCSCF wave function, from which the angle-resolved photoelectron energy spectrum, and more generally, photoelectron reduced density matrices (RDMs) are readiliy obtained. The tSURFF method applied to the TD-MCSCF wave function, in combination with an efficient absorbing boundary offered by the infinite-range exterior complex scaling, enables accurate {\it ab initio} computations of photoelectron energy spectra from multielectron systems subject to an intense and ultrashort laser pulse with a computational cost significantly reduced compared to that required in projecting the total wave function onto scattering states. We apply the present implementation to the photoionization of Ne exposed to an attosecond extreme-ultraviolet (XUV) pulse and above-threshold ionization of Ar irradiated by an intense mid-infrared laser field, demonstrating both accuracy and efficiency of the present method.

Modeling atom-atom interactions at low energy by Jost-Kohn potentials (1902.02177v3)

Subhanka Mal, Kingshuk Adhikary, Dibyendu Sardar, Abhik Kumar Saha, Bimalendu Deb

2019-02-06

More than 65 years ago, Jost and Kohn [R. Jost and W. Kohn, {Phys. Rev.} {\bf 87}, 977 (1952)] derived an explicit expression for a class of short-range model potentials from a given effective range expansion with the -wave scattering length being negative. For , they calculated another class of short-range model potentials [R. Jost and W. Kohn, { Dan. Mat. Fys. Medd} {\bf 27}, 1 (1953)] using a method based on an adaptation from Gelfand-Levitan theory [I. M. Gel'fand and B. M. Levitan, { Dokl. Akad. Nauk. USSR} {\bf 77}, 557-560 (1951)] of inverse scattering. We here revisit the methods of Jost and Kohn in order to explore the possibility of modeling resonant finite-range interactions at low energy. We show that the Jost-Kohn potentials can account for zero-energy resonances. The -wave phase shift for positive scattering length is expressed in an analytical form as a function of the binding energy of a bound state. We show that, for small binding energy, both the scattering length and the effective range are strongly influenced by the binding energy; and below a critical binding energy the effective range becomes negative provided the scattering length is large. As a consistency check, we carry out some simple calculations to show that Jost-Kohn potentials can reproduce the standard results of contact interaction in the limit of the effective range going to zero.

Detecting and Receiving Phase Modulated Signals with a Rydberg Atom-Based Mixer (1903.10644v1)

Christopher L. Holloway, Matthew T. Simons, Joshua A. Gordon, David Novotny

2019-03-26

Recently, we introduced a Rydberg-atom based mixer capable of detecting and measuring the phase of a radio-frequency field through the electromagnetically induced transparency (EIT) and Autler-Townes (AT) effect. The ability to measure phase with this mixer allows for an atom-based receiver to detect digital modulated communication signals. In this paper, we demonstrate detection and reception of digital modulated signals based on various phase-shift keying approaches. We demonstrate Rydberg atom-based digital reception of binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK), and quadrature amplitude (QAM) modulated signals over a 19.626~GHz carrier to transmit and receive a bit stream in cesium vapor. We present measured values of Error Vector Magnitude (EVM, a common communication metric used to assess how accurate a symbol or bit stream is received) as a function of symbol rate for BPSK, QPSK, 16QAM, 32QAM, and 64QAM modulation schemes. These results allow us to discuss the bandwidth of a Rydberg-atom based receiver system.

Scientific Opportunities with an X-ray Free-Electron Laser Oscillator (1903.09317v2)

Bernhard Adams, Gabriel Aeppli, Thomas Allison, Alfred Q. R. Baron, Phillip Bucksbaum, Aleksandr I. Chumakov, Christopher Corder, Stephen P. Cramer, Serena DeBeer, Yuntao Ding, Jörg Evers, Josef Frisch, Matthias Fuchs, Gerhard Grübel, Jerome B. Hastings, Christoph M. Heyl, Leo Holberg, Zhirong Huang, Tetsuya Ishikawa, Andreas Kaldun, Kwang-Je Kim, Tomasz Kolodziej, Jacek Krzywinski, Zheng Li, Wen-Te Liao, Ryan Lindberg, Anders Madsen, Timothy Maxwell, Giulio Monaco, Keith Nelson, Adriana Palffy, Gil Porat, Weilun Qin, Tor Raubenheimer, David A. Reis, Ralf Röhlsberger, Robin Santra, Robert Schoenlein, Volker Schünemann, Oleg Shpyrko, Yuri Shvyd'ko, Sharon Shwartz, Andrej Singer, Sunil K. Sinha, Mark Sutton, Kenji Tamasaku, Hans-Christian Wille, Makina Yabashi, Jun Ye, Diling Zhu

2019-03-18

An X-ray free-electron laser oscillator (XFELO) is a new type of hard X-ray source that would produce fully coherent pulses with meV bandwidth and stable intensity. The XFELO complements existing sources based on self-amplified spontaneous emission (SASE) from high-gain X-ray free-electron lasers (XFEL) that produce ultra-short pulses with broad-band chaotic spectra. This report is based on discussions of scientific opportunities enabled by an XFELO during a workshop held at SLAC on June 29 - July 1, 2016

First principle simulation of ultra-cold ion crystals in a Penning trap with Doppler cooling and a rotating wall potential (1903.10600v1)

Chen Tang, Dominic Meiser, John J. Bollinger, Scott E. Parker

2019-03-25

A direct numerical simulation of many interacting ions in a Penning trap with a rotating wall is presented. The ion dynamics is modelled classically. Both axial and planar Doppler laser cooling are modeled using stochastic momentum impulses based on two-level atomic scattering rates. The plasmas being modeled are ultra-cold two-dimensional crystals made up of 100's of ions. We compare Doppler cooled results directly to a previous linear eigenmodes analysis. Agreement in both frequency and mode structure are obtained. Additionally, when Doppler laser cooling is applied, the laser cooled steady state plasma axial temperature agrees with the Doppler cooling limit. Numerical simulations using the approach described and benchmarked here will provide insights into the dynamics of large trapped-ion crystals, improving their performance as a platform for quantum simulation and sensing.

Superradiant laser with metastable calcium atoms (1903.10196v1)

Torben Laske, Hannes Winter, Andreas Hemmerich

2019-03-25

Cold samples of calcium atoms are prepared in the metastable P state inside an optical cavity resonant with the narrow band (375 Hz) SP intercombination line at 657 nm. We observe superradiant emission through hyperbolic secant shaped pulses released into the cavity with an intensity proportional to the square of the particle number, a duration much shorter than the natural lifetime of the P state, and a delay time fluctuating from shot to shot in excellent agreement with theoretical predictions. Our incoherent pumping scheme to produce inversion on the SP transition should be extendable to allow for continuous wave laser operation.

QED and relativistic nuclear recoil corrections to the 413 nm tune-out wavelength for the state of helium (1903.04170v2)

Yong-Hui Zhang, Fang-Fei Wu, Pei-Pei Zhang, Li-Yan Tang, Jun-Yi Zhang, K. G. H. Baldwin, Ting-Yun Shi

2019-03-11

Comparison of high accuracy calculations with precision measurement of the 413 nm tune-out wavelength of the He() state provides a unique test of quantum electro-dynamic (QED). We perform large-scale relativistic-configuration-interaction (RCI) calculations of the tune-out wavelength, that include the mass-shift operator, and fully account for leading relativistic nuclear recoil terms in the Dirac-Coulomb-Breit (DCB) Hamiltonian. We obtain the QED correction to the tune-out wavelength using perturbation theory, and the effect of finite nuclear size is also evaluated. The resulting tune-out wavelengths for the and states are 413.084 26(4) nm and 413.090 15(4) nm, respectively. Compared with the only current experimental value of 413.0938(9stat)(20syst) nm for the state, there is 1.8 discrepancy between present theoretical work and experiment, which stimulates further theoretical and higher-precision experimental investigations on the 413 nm tune-out wavelength. In addition, we also determine the QED correction for the static dipole polarizability of the He() state to be 22.5 ppm, which may enable a new test of QED in the future.

---

Keeping updated in the latest research in atomic and molecular clusters!