Atomic Physics
Relativistic calculations of the ground and inner-L-shell excited energy levels of berylliumlike ions (1901.02083v2)
M. Y. Kaygorodov, Y. S. Kozhedub, I. I. Tupitsyn, A. V. Malyshev, D. A. Glazov, G. Plunien, V. M. Shabaev
2019-01-07
Large-scale relativistic configuration-interaction method combined with many-body perturbation theory is consistently applied to calculations of the energy levels of the ground and inner-L-shell excited states of berylliumlike ions in the range
. The quantum electrodynamics, nuclear recoil, and frequency-dependent Breit corrections are taken into account. The obtained results are supplemented with the systematical estimation of the uncertainties.
On the possibility of observable signatures of 
and 
lines on the spectra of astrophysical sources (1903.11837v1)
V. Dubrovich, T. Zalialiutdinov
2019-03-28
We examine the processes of the luminescence in subordinate lines of muonic hydrogen
and muonic helium ion
in the presence of background source of X-ray emission. It is supposed that a certain amount of muonic atoms existing in the vicinity of astrophysical source reemits absorbed radiation in the subordinate lines. The intensity of luminescence of such a process is proportional to the quantum yield which was calculated for different pumping channels and different models of spectra. It is shown that the luminescent lines of muonic hydrogen and muonic helium ion can be very noticeable in the spectrum of background source.
Application of the time-dependent surface flux method to the time-dependent multiconfiguration self-consistent-field method (1903.10743v2)
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.
Attosecond dynamics through a Fano resonance: Monitoring the birth of a photoelectron (1903.11698v1)
V. Gruson, L. Barreau, Á. Jiménez-Galan, F. Risoud, J. Caillat, A. Maquet, B. Carré, F. Lepetit, J-F. Hergott, T. Ruchon, L. Argenti, R. Taïeb, F. Martín, P. Salières
2019-03-27
Amplitude and phase of wavepackets encode the dynamics of quantum systems. However, the rapidity of electron dynamics on the attosecond timescale has precluded their complete measurement in the time domain. Here, we demonstrate that spectrally-resolved electron interferometry reveals the amplitude and phase of a photoelectron wavepacket created through a Fano autoionizing resonance in helium. Replicas obtained by two-photon transitions interfere with reference wavepackets formed through smooth continua, allowing the full temporal reconstruction, purely from experimental data, of the resonant wavepacket released in the continuum. This in turn resolves the buildup of the autoionizing resonance on attosecond timescale. Our results, in excellent agreement with ab initio time-dependent calculations, raise prospects for both detailed investigations of ultrafast photoemission dynamics governed by electron correlation, as well as coherent control over structured electron wave-packets.
Relativistic Coupled-Cluster Study of Diatomic Metal-Alkali Molecules for Electron Electric Dipole Moment Searches (1903.11669v1)
A. Sunaga, M. Abe, V. S. Prasannaa, T. Aoki, M. Hada
2019-03-27
Recent improvements in experimental techniques for preparing ultracold molecules that contain alkali atoms (e.g., Li, Na, and K) have been reported. Based on these advances in ultracold molecules, new searches for the electric dipole moment of the electron and the scalar-pseudoscalar interaction can be proposed on such systems. We calculate the effective electric fields (Eeff) and the S-PS coefficients (Ws) of SrA and HgA (A = Li, Na, and K) molecules at the Dirac-Fock (DF) and the relativistic coupled cluster (RCC) levels. We elaborate on the following points: i) Basis set dependence of the molecular properties in HgA, ii) Analysis of Eeff and Ws in SrA and HgA, and comparison with their fluoride and hydride counterparts, iii) Ratio of Ws to Eeff (Ws/Eeff) at the DF and the correlation RCC levels of theory.
Factor of Lithiumlike Silicon: New Challenge to Bound-State QED (1903.11609v1)
D. A. Glazov, F. Köhler-Langes, A. V. Volotka, F. Heiße, K. Blaum, G. Plunien, W. Quint, V. M. Shabaev, S. Sturm, G. Werth
2019-03-27
The recently established agreement between experiment and theory for the
and experimental
values of the
Si
. The theoretical precision now is limited by the many-electron two-loop contributions of the bound-state QED. The experimental value is accurate enough to test these contributions on a few percent level.
Probing Nonlocal Spatial Correlations in Quantum Gases with Ultra-long-range Rydberg Molecules (1903.11526v1)
J. D. Whalen, S. K. Kanungo, R. Ding, M. Wagner, R. Schmidt, H. R. Sadeghpour, S. Yoshida, J. Burgdörfer, F. B. Dunning, T. C. Killian
2019-03-27
We present photo-excitation of ultra-long-range Rydberg molecules as a probe of spatial correlations in quantum gases. Rydberg molecules can be created with well-defined internuclear spacing, set by the radius of the outer lobe of the Rydberg electron wavefunction
. By varying the principal quantum number
of the target Rydberg state, the molecular excitation rate can be used to map the pair-correlation function of the trapped gas
. We demonstrate this with ultracold Sr gases and probe pair-separation length scales ranging from
, which are on the order of the thermal de Broglie wavelength for temperatures around 1
K. We observe bunching for a single-component Bose gas of
Sr and anti-bunching due to Pauli exclusion at short distances for a polarized Fermi gas of
Sr, revealing the effects of quantum statistics.
A Frenet-Serret Interpretation of Particle Dynamics in High-Intensity Laser Fields (1903.11463v1)
D. Seipt, A. G. R. Thomas
2019-03-27
In this paper we discuss the dynamics of charged particles in high-intensity laser fields in the context of the Frenet-Serret formalism, which describes the intrinsic geometry of particle worldlines. We find approximate relations for the Frenet-Serret scalars and basis vectors relevant for high-intensity laser particle interactions. The onset of quantum effects relates to the curvature radius of classical trajectories being on the order of the Compton wavelength. The effects of classical radiation reaction are discussed, as well as the classical precession of the spin-polarization vector according to the Thomas-Bargman-Michel-Telegdi (T-BMT) equation. We comment on the derivation of the photon emission rate in strong-field QED beyond the locally constant field approximation, which is used in Monte Carlo simulations of quantum radiation reaction. Such a numerical simulation is presented for a possible experiment to distinguish between classical and quantum mechanical models of radiation reaction.
Simulations of Majorana spin flips in an antihydrogen trap (1903.11443v1)
M. A. Alarcón, C. J. Riggert, F. Robicheaux
2019-03-27
The properties of antihydrogen (
) have, thus far, been probed at magnetic fields of
T. It may be fruitful to perform some of these measurements at magnetic fields approaching 0 T. In this case, there could occur zeros in the magnitude of the
-field. The number and properties of the magnetic field zeros are investigated. For typical magnetic field geometries in
Compact laser system for a laser-cooled ytterbium ion microwave frequency standard (1811.10451v2)
S. Mulholland, H. A. Klein, G. P. Barwood, S. Donnellan, P. B. R. Nisbet-Jones, G. Huang, G. Walsh, P. E. G. Baird, P. Gill
2018-11-26
The development of a transportable microwave frequency standard based on the ground-state transition of
at ~12.6 GHz requires a compact laser system for cooling the ions, clearing out of long-lived states and also for photoionisation. In this paper, we describe the development of a suitable compact laser system based on a 6U height rack-mounted arrangement with overall dimensions
mm. Laser outputs at 369 nm (for cooling), 399 nm (photoionisation), 935 nm (repumping) and 760 nm (state clearout) are combined in a fiber arrangement for delivery to our linear ion trap and we demonstrate this system by cooling of
