Subjects -> ELECTRONICS (Total: 207 journals)
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 Journal of Physics B: Atomic, Molecular and Optical PhysicsJournal Prestige (SJR): 0.85 Citation Impact (citeScore): 2Number of Followers: 32      Hybrid journal (It can contain Open Access articles) ISSN (Print) 0953-4075 - ISSN (Online) 1361-6455 Published by IOP  [74 journals]
• Study of the possibilities with combinations of circularly and linearly
polarized light for attosecond delay investigations
• Authors: J Sörngård; J M Dahlström E Lindroth
First page: 134003
Abstract: We present calculations on the atomic delay in photoionzation obtained with different combinations of linearly and circularly polarized light, and show how a tensor operator approach can be used to readily obtain results for any combination from a single calculation of the radial integrals. We find that for certain choices of polarization and detection geometry a single time-delay measurement is enough to extract the atomic delay since the relative phase in a RABBIT type measurement will be imprinted on the photo electron anisotropy. We show further that the full angular dependence can be qualitatively understood from a plane wave analysis. The results are illustrated by many-body calculations of two-photon above threshold ionization on argon.
Citation: Journal of Physics B: Atomic, Molecular and Optical Physics
PubDate: 2020-06-08T23:00:00Z
DOI: 10.1088/1361-6455/ab84c6
Issue No: Vol. 53, No. 13 (2020)

• Optical control of atom-ion collisions using a Rydberg state
• Authors: Limei Wang; Markus Deiß, Georg Raithel Johannes Hecker Denschlag
First page: 134005
Abstract: We present a method to control collisions between ultracold neutral atoms in the electronic ground state and trapped ions. During the collision, the neutral atom is resonantly excited by a laser to a low-field-seeking Rydberg state, which is repelled by the ion. As the atom is reflected from the ion, it is de-excited back into its electronic ground level. The efficiency of shielding is analyzed as a function of laser frequency and power, initial atom-ion collision energy, and collision angle. The suitability of several Rydberg levels of Na and Rb for shielding is discussed. Useful applications of shielding include the suppression of unwanted chemical reactions between atoms and ions, a prerequisite for controlled atom-ion interactions.
Citation: Journal of Physics B: Atomic, Molecular and Optical Physics
PubDate: 2020-06-04T23:00:00Z
DOI: 10.1088/1361-6455/ab7d24
Issue No: Vol. 53, No. 13 (2020)

hollow-core photonic-bandgap fiber
• Authors: Taehyun Yoon; Michal Bajcsy
First page: 135002
Abstract: We numerically simulate gravity-assisted loading of laser-cooled atoms into a hollow-core fiber.  For this, we compute the trajectories of falling atoms and test the success or failure of loading with a range of atoms’ initial positions and velocities. By overlapping these results with the position and velocity distribution of the trapped atomic cloud, the number of loaded atoms is estimated without a random sampling process. We present our predictions for the atomic cloud’s loading efficiency into a photonic-bandgap fiber with a 7.5 μ m-diameter hollow core for various experimental conditions, such as the initial temperature, the cloud position and size, and the dipole trap power, and compare the predictions to experimental data. Our approach reduces the computational resources and time compared to the Monte-Carlo approach used in previously reported works.
Citation: Journal of Physics B: Atomic, Molecular and Optical Physics
PubDate: 2020-06-03T23:00:00Z
DOI: 10.1088/1361-6455/ab8946
Issue No: Vol. 53, No. 13 (2020)

• Calculations of Bethe logarithm for hydrogen and helium using B-splines in
different gauges
• Authors: Yong-Hui Zhang; Lu-Jun Shen, Chang-Min Xiao, Jun-Yi Zhang Ting-Yun Shi
First page: 135003
Abstract: The efficient and simple B-splines variational method is successfully used to calculate Bethe logarithm for the hydrogen atom in the velocity and length gauges. The ground state Bethe logarithm of hydrogen with fourteen accurate figures is obtained in the velocity gauge, and in the length gauge the ground state value has eleven accurate figures. Present velocity- and length-gauge results for the n s, n p, n d, and n f states up to n = 200 of hydrogen are above the 10 −10 level of relative difference, which represent the successful variational attempt to calculate Bethe logarithm of hydrogen in the velocity and length gauges. In addition, the B-splines variational method is successfully extended to calculate Bethe logarithm for the helium atom combined with configuration interaction. Results of numerical calculations for n 1,3 S up to n = 8 states are presented in the acceleration gauge, the velocity gauge, and a hy...
Citation: Journal of Physics B: Atomic, Molecular and Optical Physics
PubDate: 2020-06-04T23:00:00Z
DOI: 10.1088/1361-6455/ab8b41
Issue No: Vol. 53, No. 13 (2020)

• Calculations of ##IMG##
[http://ej.iop.org/images/0953-4075/53/13/135101/toc_bab87e8ieqn1.gif] {$\mathcal{P}$}
and ##IMG##
[http://ej.iop.org/images/0953-4075/53/13/135101/toc_bab87e8ieqn2.gif] {$\mathcal{T}$}
-odd interaction constants of alkaline-earth...
• Authors: Renu Bala; H S Nataraj Malaya K Nayak
First page: 135101
Abstract: We have reported the results of ab initio calculations of parity- and time-reversal-odd interaction constants for the ground state of alkaline-earth monofluorides. The Kramers-restricted configuration interaction method limited to single and double excitations in conjunction with the quadruple zeta quality basis sets have been employed to perform these four-component relativistic calculations. The results are compared with the existing semi-empirical and other theoretical results, wherever available.
Citation: Journal of Physics B: Atomic, Molecular and Optical Physics
PubDate: 2020-06-02T23:00:00Z
DOI: 10.1088/1361-6455/ab87e8
Issue No: Vol. 53, No. 13 (2020)

• Relativistic coupled-cluster study of BaF in search of
##IMG## [http://ej.iop.org/images/0953-4075/53/13/135102/toc_bab84c8ieqn1.gif]
{$\boldsymbol{\mathcal{CP}}$} violation
• Authors: Kaushik Talukdar; Malaya K. Nayak, Nayana Vaval Sourav Pal
First page: 135102
Abstract: BaF is one of the potential candidates for the experimental search of the electric dipole moment of the electron (eEDM). The NL-eEDM collaboration is building a new experimental set up to measure the eEDM using the BaF molecule (The NL-eEDM collaboration, 2018 Eur. Phys. J. D 72 : 197). To analyze the results of such an experiment, one would require the accurate value of the molecular ##IMG## [http://ej.iop.org/images/0953-4075/53/13/135102/bab84c8ieqn2.gif] {$\mathcal{P,T}$} -odd interaction parameters that cannot be measured from any experiment. In this work, we report the precise value of the ##IMG## [http://ej.iop.org/images/0953-4075/53/13/135102/bab84c8ieqn3.gif] {$\mathcal{P,T}$} -odd interaction parameters of the BaF molecule obtained from the four-component relativistic coupled-cluster calculations. We also calculate the hyperfine structure (HFS) constants of the same molecule to assess the reliability of the report...
Citation: Journal of Physics B: Atomic, Molecular and Optical Physics
PubDate: 2020-06-03T23:00:00Z
DOI: 10.1088/1361-6455/ab84c8
Issue No: Vol. 53, No. 13 (2020)

• Calculation of the electronic, nuclear, rotational, and vibrational
stopping cross sections for H atoms irradiation on H 2 , N 2 and O 2 gas
targets at low collision energies
• Authors: R Cabrera-Trujillo; A G El Hachimi
First page: 135203
Abstract: In this work, we present a study of hydrogen atoms interacting with hydrogen, nitrogen, and oxygen molecules in the gas phase in order to determine the projectile energy loss, the stopping cross section, and energy deposition with implication in hydrogen and proton dosimetry and radiotherapy. Our calculations are performed with a density-functional tight-binding (DFTB) as well as by an ab initio electron-nuclear dynamic (END). The H atoms have a low collision energy in the range of 1–100 eV for the DFTB and 1–1000 eV for the END. We decompose the projectile energy deposition into its electronic, nuclear, rotational, and vibrational energy target contributions. We find that for low collisions energy, DFTB and END are in fair agreement when comparing the nuclear and rotational contributions. However, we find discrepancies for the vibrational and electronic energy loss between both approaches. The largest discrepancy is found in the electronic energy loss as DFTB carries the...
Citation: Journal of Physics B: Atomic, Molecular and Optical Physics
PubDate: 2020-06-04T23:00:00Z
DOI: 10.1088/1361-6455/ab8834
Issue No: Vol. 53, No. 13 (2020)

• Steady states of a driven dissipative dipolar XXZ chain
• Authors: C D Parmee; N R Cooper
First page: 135302
Abstract: We study theoretically a driven dissipative one-dimensional XXZ spin-1/2 chain with dipole coupling and a tunable strength of the Ising and XY interaction. Within a mean-field approximation, we find a rich phase diagram with uniform, spin density wave, antiferromagnetic and oscillatory phases, as well as regions of phase bistability. We study the phase diagram of small quantum systems using exact diagonalisation, and compare the results to the mean-field theory. We find that while expectation values only capture the uniform phases of the mean-field theory, fluctuations about these expectation values give signatures of spatially non-uniform phases and bistabilities. We find these signatures for all ratios of the Ising to XY interaction, showing that they appear to be general features of spin-1/2 systems.
Citation: Journal of Physics B: Atomic, Molecular and Optical Physics
PubDate: 2020-06-08T23:00:00Z
DOI: 10.1088/1361-6455/ab8949
Issue No: Vol. 53, No. 13 (2020)

• Ab initio electronic structure of the Sr 2 + molecular ion
• Authors: Michał Śmiałkowski; Tatiana Korona Michał Tomza
First page: 135303
Abstract: Molecular ions formed in cold hybrid ion–atom experiments may find interesting applications ranging from precision measurements to controlled chemical reactions. Here, we investigate the electronic structure of the ##IMG## [http://ej.iop.org/images/0953-4075/53/13/135303/bab84c5ieqn2.gif] {${\mathrm{Sr}}_{2}^{+}$} molecular ion, which may be produced by photoassociation of laser-cooled Sr + ions immersed in an ultracold gas of Sr atoms or by ionization of ultracold Sr 2 molecules. Using ab initio electronic structure methods, such as the coupled cluster and configuration interaction ones with small-core relativistic energy-consistent pseudopotentials and large Gaussian basis sets, we calculate potential energy curves for the ground and 41 excited electronic states, and electric dipole transition moments between them. We show that alkaline-earth molecular ions, despite their apparently simple structure with only three valence elect...
Citation: Journal of Physics B: Atomic, Molecular and Optical Physics
PubDate: 2020-06-04T23:00:00Z
DOI: 10.1088/1361-6455/ab84c53w
Issue No: Vol. 53, No. 13 (2020)

• Prospects in rare-gas hydride ions for terahertz frequency standards
• Authors: Masatoshi Kajita; Naoki Kimura
First page: 135401
Abstract: A proposal is given to use the ##IMG## [http://ej.iop.org/images/0953-4075/53/13/135401/bab894bieqn1.gif] {${X}^{1}{\Sigma}\left(v,J,F\right)=\left(0,0,1/2\right)-\left(0,1,1/2\right)$} transition of the HeH + (2.0 THz), NeH + (1.0 THz), and ArH + (0.62 THz) molecular ions as novel frequency standards in the terahertz region. This transition is free from the electric-quadrupole shift, and the DC Stark and Zeeman shifts are much less than those of the CaH + and MgH + molecular ions. These transitions are useful for locking the frequencies of oscillators like quantum cascade lasers (QCL) or resonant tunnel diodes (RTD) with uncertainties of 10 −15 .
Citation: Journal of Physics B: Atomic, Molecular and Optical Physics
PubDate: 2020-06-02T23:00:00Z
DOI: 10.1088/1361-6455/ab894b
Issue No: Vol. 53, No. 13 (2020)

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