x, 220 p. ; 29 cm
Topic: Atomic physics
Atomic Physics
Topic: Atomic Physics
4
4.0
Jun 30, 2018
06/18
by
James O. Hornkohl; Christian G. Parigger
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Rotational line strengths, computed from eigenvectors of Hund's case (a) matrix representations of the upper and lower Hamiltonians using Wigner-Witmer basis functions, show a larger than expected influence from the well known perturbation in the (5,4) band. Comparisons with National Solar Observatory experimental Fourier transform spectroscopy data reveal nice agreement of measured and predicted spectra. Keywords: Diatomic spectroscopy, rotational line strengths, H\"onl-London factors,...
Topics: Atomic Physics, Physics
Source: http://arxiv.org/abs/1701.08704
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4.0
Jun 29, 2018
06/18
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A. V. Viatkina; M. G. Kozlov; V. V. Flambaum
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Energy level spectrum of protactinium atom (Pa, Z=91) is simulated with a CI calculation. Levels belonging to the separate manifolds of a given total angular momentum and parity $J^\pi$ exhibit distinct properties of many-body quantum chaos. Moreover, an extremely strong enhancement of small perturbations takes place. As an example, effective three-electron interaction is investigated and found to play a significant role in the system. Chaotic properties of the eigenstates allow one to develop...
Topics: Atomic Physics, Physics
Source: http://arxiv.org/abs/1611.01028
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4.0
Jun 29, 2018
06/18
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V. Zhelyazkova; S. D. Hogan
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Helium atoms have been prepared in the circular $|n=55,\ell=54,m_{\ell}=+54\rangle$ Rydberg state using the crossed electric and magnetic fields method. The atoms, initially travelling in pulsed supersonic beams, were photoexcited from the metastable $1s2s\,^3S_1$ level to the outermost, $m_{\ell}=0$ Rydberg-Stark state with $n=55$ in the presence of a strong electric field and weak perpendicular magnetic field. Following excitation, the electric field was adiabatically switched off causing the...
Topics: Atomic Physics, Physics
Source: http://arxiv.org/abs/1611.01308
4
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Jun 29, 2018
06/18
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S. Truppe; H. J. Williams; N. J. Fitch; M. Hambach; T. E. Wall; E. A. Hinds; B. E. Sauer; M. R. Tarbutt
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Using frequency-chirped radiation pressure slowing, we precisely control the velocity of a pulsed CaF molecular beam down to a few m/s, compressing its velocity spread by a factor of 10 while retaining high intensity: at a velocity of 15~m/s the flux, measured 1.3~m from the source, is 7$\times$10$^{5}$ molecules per cm$^{2}$ per shot in a single rovibrational state. The beam is suitable for loading a magneto-optical trap or, when combined with transverse laser cooling, improving the precision...
Topics: Atomic Physics, Physics
Source: http://arxiv.org/abs/1605.06055
4
4.0
Jun 29, 2018
06/18
by
Guillaume Labeyrie; Robin Kaiser
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When applying two counter-propagating laser beams to a cold cloud of Rubidium atoms, we observe the spontaneous formation of intensity patterns associated with a spatial structuration of the atomic spins. We study the average number of defects in these patterns as a function of the sweep time employed to cross the transition threshold. We observe a power-law decrease of the number of defects with increasing sweep time, typical of the Kibble-Zurek mechanism. The measured exponent is consistent...
Topics: Atomic Physics, Physics
Source: http://arxiv.org/abs/1610.00917
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Jun 30, 2018
06/18
by
Jean-Luc Robyr; Paul Knowles; Antoine Weis
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The AC Stark shift induced by blackbody radiation is a major source of systematic uncertainty in present-day cesium microwave frequency standards. The shift is parametrized in terms of a third-order electric polarizability $\alpha_0^{(3)}$ that can be inferred from the static electric field displacement of the clock transition resonance. In this paper, we report on an all-optical CPT pump-probe experiment measuring the differential polarizability $\Delta \alpha_0^{(3)} = \alpha_0^{(3)}(F{=}4) -...
Topics: Physics, Atomic Physics
Source: http://arxiv.org/abs/1402.5776
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4.0
Jun 30, 2018
06/18
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Amy Gardner; Kevin Sheridan; William Groom; Nicolas Seymour-Smith; Matthias Keller
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In this paper we present a technique for the precise measurement of electric dipole allowed transitions in trapped ions. By applying a probe and a cooling laser in quick succession, the full transition can be probed without causing distortion from heating the ion. In addition, two probes can be utilized to measure a dispersion-like signal, which is well suited to stabilizing the laser to the transition. We have fully characterized the parameters for the measurement and find that it is possible...
Topics: Physics, Atomic Physics
Source: http://arxiv.org/abs/1403.7049
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7.0
Jun 30, 2018
06/18
by
Vladimir S. Ivanov; Yuri V. Rozhdestvensky; Kalle-Antti Suominen
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We present a scheme of the high-precise three-dimensional (3D) localization by the measurement of the atomic-level population. The scheme is applied to a four-level tripod-type atom coupled by three strong standing waves and a probe running wave. As a result, the atom can be localized in volumes that are substantially smaller than a cubic optical wavelength. The upper-level distribution depends crucially on the atom-field coupling and it forms 3D periodic structures composed of spheres,...
Topics: Physics, Atomic Physics
Source: http://arxiv.org/abs/1406.2156
3
3.0
Jun 30, 2018
06/18
by
V K Dolmatov; M B Cooper; M E Hunter
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The initial insight into electron elastic scattering off endohedral fullerenes A@C60 is gained in the framework of a theoretical approach where the C60 cage is modelled by a rectangular (in the radial coordinate) potential well, as in many other A@C60 studies. The effect of a noticeably weaker electron elastic scattering off A@C60 compared to that off empty C60 or even the isolated atom A itself, as well as a strong sensitivity of e + A@C60 scattering to the spin of the captured atom A are...
Topics: Physics, Atomic Physics
Source: http://arxiv.org/abs/1401.2632
3
3.0
Jun 30, 2018
06/18
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B. M. McLaughlin; H. D. L. Lamb; I. C. Lane; J. F. McCann
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Ultracold hybrid ion-atom traps offer the possibility of microscopic manipulation of quantum coherences in the gas using the ion as a probe. However, inelastic processes, particularly charge transfer can be a significant process of ion loss and has been measured experimentally for the Yb$^{+}$ ion immersed in a Rb vapour. We use first-principles quantum chemistry codes to obtain the potential energy curves and dipole moments for the lowest-lying energy states of this complex. Calculations for...
Topics: Physics, Atomic Physics
Source: http://arxiv.org/abs/1404.6579
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Jun 28, 2018
06/18
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Artjom Krükow; Amir Mohammadi; Arne Härter; Johannes Hecker Denschlag; Jesús Pérez-Ríos; Chris H. Greene
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We study three-body recombination of Ba$^+$ + Rb + Rb in the mK regime where a single $^{138}$Ba$^{+}$ ion in a Paul trap is immersed into a cloud of ultracold $^{87}$Rb atoms. We measure the energy dependence of the three-body rate coefficient $k_3$ and compare the results to the theoretical prediction, $k_3 \propto E_{\textrm{col}}^{-3/4}$ where $E_{\textrm{col}}$ is the collision energy. We find agreement if we assume that the non-thermal ion energy distribution is determined by at least two...
Topics: Atomic Physics, Physics
Source: http://arxiv.org/abs/1510.04938
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Jun 28, 2018
06/18
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R. Blümel; J. E. Wells; D. S. Goodman; J. M. Kwolek; W. W. Smith
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We predict that the steady-state ion number $N_s$ for radio-frequency (rf) traps, loaded at a rate of $\lambda$ particles per unit time, shows universal non-monotonic behavior as a function of loading rate $\lambda$. The shape of $N_s(\lambda)$, characterized by four dynamical regions, is universal in the sense that it is predicted to manifest itself in all rf traps independently of the details of their construction. For $\lambda\ll$ 1 particles / rf cycle (Region I), as expected,...
Topics: Atomic Physics, Physics
Source: http://arxiv.org/abs/1507.04731
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14
Jun 28, 2018
06/18
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Markus Mack; Jens Grimmel; Florian Karlewski; Lőrinc Sárkány; Helge Hattermann; József Fortágh
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We have developed an all-optical method for measuring the lifetimes of $n S$ and $n D$ Rydberg states and demonstrate its capabilities with measurements on a dilute cloud of ultracold ${}^{87}$Rb atoms in a cryogenic environment. The method is based on the time-resolved observation of resonant light absorption by ground state atoms and selective transfer of Rydberg atoms into the ground state at varying delay times in order to reconstruct Rydberg decay curves. Our measurements of the...
Topics: Atomic Physics, Physics
Source: http://arxiv.org/abs/1507.02427
3
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Jun 29, 2018
06/18
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I. I. Tupitsyn; M. G. Kozlov; M. S. Safronova; V. M. Shabaev; V. A. Dzuba
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The quantum electrodynamics (QED) corrections are directly incorporated into the most accurate treatment of the correlation corrections for ions with complex electronic structure of interest to metrology and tests of fundamental physics. We compared the performance of four different QED potentials for various systems to access the accuracy of QED calculations and to make prediction of highly charged ion properties urgently needed for planning future experiments. We find that all four potentials...
Topics: Atomic Physics, Physics
Source: http://arxiv.org/abs/1607.07064
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4.0
Jun 28, 2018
06/18
by
Ljerka Nenadović; John J. McFerran
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We have carried out concurrent optical frequency measurements of the $(6s^{2})\,^{1}S_{0} -(6s6p)\,^{3}P_{1}$ ($F=\frac{3}{2}$) and $(6s^{2})\,^{1}S_{0} -(6s6p)\,^{3}P_{0}$ transitions in $^{171}$Yb, and in so doing have determined the frequency separation between the $^{3}P_{0}$ ($F=\frac{1}{2}$) and $^{3}P_{1}$ ($F=\frac{3}{2}$) levels with an uncertainty in the ppb range. The knowledge of this frequency interval will aid experiments relying on the $^{1}S_{0}-\,^{3}P_{0}$ line in $^{171}$Yb...
Topics: Atomic Physics, Physics
Source: http://arxiv.org/abs/1510.01037
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5.0
Jun 29, 2018
06/18
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Davide Faccialà; Stefan Pabst; Barry D. Bruner; Anna G. Ciriolo; Sandro De Silvestri; Michele Devetta; Matteo Negro; Hadas Soifer; Salvatore Stagira; Nirit Dudovich; Caterina Vozzi
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We investigated the giant resonance in Xenon by high-order harmonic generation spectroscopy driven by a two-color field. The addition of a non-perturbative second harmonic component parallel to the driving field breaks the symmetry between neighboring sub-cycles resulting in the appearance of spectral caustics at two distinct cut-off energies. By controlling the phase delay between the two color components it is possible to tailor the harmonic emission in order to amplify and isolate the...
Topics: Atomic Physics, Physics
Source: http://arxiv.org/abs/1603.01755
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6.0
Jun 29, 2018
06/18
by
Bonnie L. Schmittberger; Daniel J. Gauthier
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eye 6
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The study of transverse optical pattern formation has been studied extensively in nonlinear optics, with a recent experimental interest in studying the phenomenon using cold atoms, which can undergo real-space self-organization. Here, we describe our experimental observation of pattern formation in cold atoms, which occurs using less than 1 microWatt of applied power. We show that the optical patterns and the self-organized atomic structures undergo continuous symmetry-breaking, which is...
Topics: Atomic Physics, Physics
Source: http://arxiv.org/abs/1603.06280
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7.0
Jun 29, 2018
06/18
by
M. G. Bustamante; V. D. Rodríguez
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eye 7
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A unitary model describing the electronic transitions in an atom subject to a strong high frequency laser pulse is proposed. The model fully accounts for the initial state coupling with the continuum spectrum. Continuum-continuum as well as discrete-discrete transitions are neglected. The model leads to a single integro-differential equation for the initial state amplitude. Exact numerical and approximate closed semi-analytical solutions of this equation are obtained. A comparison of present...
Topics: Atomic Physics, Physics
Source: http://arxiv.org/abs/1605.02110
3
3.0
Jun 30, 2018
06/18
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Yuichiro Yano; Wujie Gao; Shigeyoshi Goka; Masatoshi Kajita
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The ac Stark shift (or light shift) of the 6$^{2}$S$_{1/2}$ (F $=$ 3 $\leftrightarrow $ 4) transition in $^{133}$Cs, as observed through coherent population trapping under pulsed excitation, is measured using a $^{133}$Cs gas cell and the $D_1$-line vertical-cavity surface-emitting laser. This light shift can be calculated using density-matrix analysis. We derive an expression for this shift as a function of light intensity, showing that it varies linearly with respect to light intensity only...
Topics: Physics, Atomic Physics
Source: http://arxiv.org/abs/1401.3497
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Jun 30, 2018
06/18
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A. Yu. Voronin; V. V. Nesvizhevsky; G. Dufour; P. Debu; A. Lambrecht; S. Reynaud; O. D. Dalkarov; E. A. Kupriyanova; P. Froelich
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We study a method to induce resonant transitions between antihydrogen ($\bar{H}$) quantum states above a material surface in the gravitational field of the Earth. The method consists of applying a gradient of magnetic field, which is temporally oscillating with the frequency equal to a frequency of transition between gravitational states of antihydrogen. A corresponding resonant change in the spatial density of antihydrogen atoms could be measured as a function of the frequency of applied...
Topics: Physics, Atomic Physics
Source: http://arxiv.org/abs/1403.4783
3
3.0
Jun 30, 2018
06/18
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D. Kielpinski; R. T. Sang; I. V. Litvinyuk
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As the simplest atomic system, the hydrogen atom plays a key benchmarking role in laser and quantum physics. Atomic hydrogen is a widely used atomic test system for theoretical calculations of strong-field ionization, since approximate theories can be directly compared to numerical solutions of the time-dependent Schr\"odinger equation. However, relatively little experimental data is available for comparison to these calculations, since atomic hydrogen sources are difficult to construct...
Topics: Physics, Atomic Physics
Source: http://arxiv.org/abs/1403.6548
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Jun 30, 2018
06/18
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A. N. Petrov; L. V. Skripnikov; A. V. Titov; N. R. Hutzler; P. W. Hess; B. R. O'Leary; B. Spaun; D. DeMille; G. Gabrielse; J. M. Doyle
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The current limit on the electron's electric dipole moment, $|d_\mathrm{e}|
Topics: Physics, Atomic Physics
Source: http://arxiv.org/abs/1404.4024
3
3.0
Jun 30, 2018
06/18
by
K. Beloy
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We identify a potential means to extract the $^{229g}$Th $\rightarrow$ $^{229m}$Th nuclear excitation energy from precision microwave spectroscopy of the $5F_{5/2,7/2}$ hyperfine manifolds in the ion $^{229g}$Th$^{3+}$. The hyperfine interaction mixes this ground fine structure doublet with states of the nuclear isomer, introducing small but observable shifts to the hyperfine sub-levels. We demonstrate how accurate atomic structure calculations may be combined with measurement of the hyperfine...
Topics: Physics, Atomic Physics
Source: http://arxiv.org/abs/1402.3221
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Jun 29, 2018
06/18
by
Johann Förster; Etienne Plesiat; Alvaro Magana; Alejandro Saenz
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The geometry-dependent ionization behavior of the ammonia molecule is investigated. Different theoretical approaches for obtaining the ionization yield are compared, all of them showing a strong dependence of the ionization yield on the inversion coordinate at long wavelengths ($\geq$ 800 nm). It is shown how this effect can be exploited to create and probe nuclear wave packets in neutral ammonia using Lochfra{\ss}. Furthermore, imaging of a wave packet tunneling through the barrier of a...
Topics: Atomic Physics, Physics
Source: http://arxiv.org/abs/1608.01861
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5.0
Jun 29, 2018
06/18
by
V. K. Dolmatov; M. Ya. Amusia; L. V. Chernysheva
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A deeper insight into electron elastic scattering off endohedral fullerenes $A$@C$_{60}$ is provided. The study accounts for polarization of both the encapsulated atom $A$ and C$_{60}$ cage by an incident electron. It is carried out in the framework of the combination of both a model and the first-principle approximations. A core principle of the model is that the C$_{60}$ cage itself is presented by an attractive spherical potential of a certain inner radius, thickness, and depth. The main...
Topics: Atomic Physics, Physics
Source: http://arxiv.org/abs/1609.07567
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5.0
Jun 29, 2018
06/18
by
D. H. Jakubassa-Amundsen
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Inspired by the work of Pratt and coworkers on a sum rule for the polarization correlations in electron bremsstrahlung when the outgoing electron is not observed, we derive the corresponding sum rule for the elementary process of bremsstrahlung. This sum rule is valid for arbitrary electron wavefunctions provided the electron is emitted in the reaction plane. The numerical evaluation of this sum rule within the Dirac partial-wave theory for bare inert spin-zero nuclei and collision energies in...
Topics: Atomic Physics, Physics
Source: http://arxiv.org/abs/1610.09137
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5.0
Jun 29, 2018
06/18
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Patrycja Stefańska
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In this paper we present tabulated data for magnetic-dipole-to-electric-quadrupole cross-susceptibilities ($\chi_{\textrm{M}1 \to \textrm{E}2}$) for Dirac one-electron atoms with a pointlike, spinless and motionless nucleus of charge $Ze$. Numerical values of this susceptibility for the hydrogen atom ($Z=1$) and for hydrogenic ions with $2 \leqslant Z \leqslant 137$ are computed from the general analytical formula, recently derived by us [P. Stefa{\'n}ska, Phys. Rev. A 93 (2016) 022504], valid...
Topics: Atomic Physics, Physics
Source: http://arxiv.org/abs/1611.01995
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3.0
Jun 30, 2018
06/18
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Robert A. Müller; Andrey V. Volotka; S. Fritzsche; A. Surzhykov
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We investigate the deexcitation of the $^{229}$Th nucleus via the excitation of an electron. Detailed calculations are performed for the enhancement of the nuclear decay width due to this so called electron bridge (EB) compared to the direct photoemission from the nucleus. The results are obtianed for triply ionized thorium by using a B-spline pseudo basis approach to solve the Dirac equation for a local $x_\alpha$ potential. This approach allows for an approximation of the full electron...
Topics: Atomic Physics, Physics
Source: http://arxiv.org/abs/1703.06628
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3.0
Jun 30, 2018
06/18
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D. G. Green; G. F. Gribakin
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Annihilation momentum densities and correlation enhancement factors for low-energy positron annihilation on valence and core electrons of noble-gas atoms are calculated using many-body theory. s, p and d-wave positrons of momenta up to the positronium-formation threshold of the atom are considered. The enhancement factors parametrize the effects of short-range electron-positron correlations which increase the annihilation probability beyond the independent-particle approximation. For all...
Topics: Atomic Physics, Physics
Source: http://arxiv.org/abs/1703.06980
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3.0
Jun 29, 2018
06/18
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Jens Svensmark; Oleg I. Tolstikhin; Lars Bojer Madsen
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We present a theoretical study of the dissociative tunneling ionization process. Analytic expressions for the nuclear kinetic energy distribution of the ionization rates are derived. A particularly simple expression for the spectrum is found by using the Born-Oppenheimer (BO) approximation in conjunction with the reflection principle. These spectra are compared to exact non-BO ab initio spectra obtained through model calculations with a quantum mechanical treatment of both the electronic and...
Topics: Atomic Physics, Physics
Source: http://arxiv.org/abs/1603.08734
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3.0
Jun 29, 2018
06/18
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Renat A. Sultanov; Dennis Guster; Sadhan K. Adhikari
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The effect of the strong $\bar{\rm p}$-p nuclear interaction in a three-charge-particle system with arbitrary masses is investigated. Specifically, the ($\bar{\rm p},\ \mu^-$,\ p) system is considered, where $\bar{p}$ is an antiproton, $\mu^-$ is a muon and p is a proton. A numerical computation in the framework of a detailed few-body approach is carried out for the following protonium (antiprotonic hydrogen) formation three-body reaction: $\bar{p} + H_{\mu}(1s) \rightarrow (\bar{p} p)_{\alpha}...
Topics: Atomic Physics, Physics
Source: http://arxiv.org/abs/1606.01325
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4.0
Jun 29, 2018
06/18
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Peter Yun; Stephane Guerandel; Emeric de Clercq
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Coherent population trapping (CPT) is extensively studied for future vapor cell clocks of high frequency stability. In the constructive polarization modulation CPT scheme, a bichromatic laser field with polarization and phase synchronously modulated is applied on an atomic medium. A high contrast CPT signal is observed in this so-called double-modulation configuration, due to the fact that the atomic population does not leak to the extreme Zeeman states, and that the two CPT dark states, which...
Topics: Atomic Physics, Physics
Source: http://arxiv.org/abs/1606.04375
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3.0
Jun 29, 2018
06/18
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Koudai Toyota
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The method of the envelope Hamiltonian [K. Toyota, U. Saalmann, and J. M. Rost, New J. Phys. {\bf 17}, 073005~(2015)] is applied to further study a detachment dynamics of a model negative ion in one-dimension in high-frequency regime. This method is based on the Floquet approach, but the time-dependency of an envelope function is explicitly kept for arbitrary pulse durations. Therefore, it is capable of describing not only a photo absorption/emission but also a non-adiabatic transition which is...
Topics: Atomic Physics, Physics
Source: http://arxiv.org/abs/1606.08712
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3.0
Jun 29, 2018
06/18
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Patrycja Stefańska
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We consider a Dirac one-electron atom placed in a weak, static, uniform magnetic field. We show that, to the first order in the strength B of the external field, the only electric multipole moments, which are induced by the perturbation in the atom, are those of an even order. Using the Sturmian expansion of the generalized Dirac-Coulomb Green function [R. Szmytkowski, J. Phys. B 30, 825 (1997); 30, 2747(E) (1997)], we derive a closed-form expression for the electric quadrupole moment induced...
Topics: Atomic Physics, Physics
Source: http://arxiv.org/abs/1606.09473
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4.0
Jun 29, 2018
06/18
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D. V. Chubukov; L. N. Labzowsky
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It is proposed to employ the P,T-odd Faraday effect, i.e. rotation of the polarization plane of the light propagating through a medium in presence of the electric field, as a tool for observation of P,T-odd effects caused by CP violation within the Standard Model. For this purpose the vapors of heavy atoms like Tl, Pb, Bi are most suitable. Estimates within the Standard Model show: provided that applied field is about 10^5 V/cm and the optical length can be as large as 70000 km, the rotation...
Topics: Atomic Physics, Physics
Source: http://arxiv.org/abs/1607.02605
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Jun 28, 2018
06/18
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A. Müller; S. Schippers; J. Hellhund; K. Holste; A. L. D. Kilcoyne; R. A. Phaneuf; C. P. Ballance; B. M. McLaughlin
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Experimental and theoretical results are reported for photoionization of Ta-like (W$^{+}$) tungsten ions. Absolute cross sections were measured in the energy range 16 to 245 eV employing the photon-ion merged-beam setup at the Advanced Light Source in Berkeley. Detailed photon-energy scans at 100 meV bandwidth were performed in the 16 to 108 eV range. In addition, the cross section was scanned at 50 meV resolution in regions where fine resonance structures could be observed. Theoretical results...
Topics: Atomic Physics, Physics
Source: http://arxiv.org/abs/1509.02113
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6.0
Jun 28, 2018
06/18
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J. K. Saha; S. Bhattacharyya; T. K. Mukherjee
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A detailed analysis on the effect of spherical impenetrable confinement on the structural properties of two-electron ions in S-states have been done. The energy values of 1sns [n = 2-4] (3Se) states of helium-like ions (Z = 2-5) are estimated within the framework of Ritz variational method by using explicitly correlated Hylleraas-type basis sets. The correlated wave functions used here are consistent with the finite boundary conditions due to spherical confinement. A comparative study between...
Topics: Atomic Physics, Physics
Source: http://arxiv.org/abs/1511.07980
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5.0
Jun 29, 2018
06/18
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Armen Sargsyan; Emmanuel Klinger; Grant Hakhumyan; Ara Tonoyan; Aram Papoyan; Claude Leroy; David Sarkisyan
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Decoupling of total electronic and nuclear spin moments of Cs atoms in external magnetic field for the case of atomic $D_1$ line, leading to onset of the hyperfine Paschen-Back regime has been studied theoretically and experimentally. Selective reflection of laser radiation from an interface of dielectric window and atomic vapor confined in a nanocell with 300 nm gap thickness was implemented for the experimental studies. The real time derivative of selective reflection signal with a frequency...
Topics: Atomic Physics, Physics
Source: http://arxiv.org/abs/1610.09807
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9.0
Jun 29, 2018
06/18
by
Qingli Jing; Lars Bojer Madsen
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We apply the Monte Carlo Wave Packet (MCWP) approach to investigate the kinetic energy release (KER) spectra of the protons following double ionization in H$_{2}$ when interacting with laser pulses with central wavelengths ranging from the near-IR (800 nm) to the mid-IR (6400 nm) regions and with durations of 3-21 laser cycles. We uncover the physical origins of the peaks in the nuclear KER spectra and ascribe them to mechanisms such as ionization following a resonant dipole transition,...
Topics: Atomic Physics, Physics
Source: http://arxiv.org/abs/1612.02031
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3.0
Jun 30, 2018
06/18
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R. Brown; Q. Prigent; A. R. Swann; G. F. Gribakin
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We determine effective collisional radii of positronium (Ps) by considering Ps states in hard-wall spherical cavities. $B$-spline basis sets of electron and positron states inside the cavity are used to construct the states of Ps. Accurate Ps energy eigenvalues are obtained by extrapolation with respect to the numbers of partial waves and radial states included in the bases. Comparison of the extrapolated energies with those of a pointlike particle provides values of the effective radius...
Topics: Atomic Physics, Physics
Source: http://arxiv.org/abs/1702.00981
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6.0
Jun 30, 2018
06/18
by
Eric Imhof; James Stickney; Matthew Squires
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Using a thermal gas, we model the signal of a trapped interferometer. This interferometer uses two short laser pulses, separated by time T, which act as a phase grating for the matter waves. Near time 2T, there is an echo in the cloud's density due to the Talbot-Lau effect. Our model uses the Wigner function approach and includes a weak residual harmonic trap. The analysis shows that the residual potential limits the interferometer's visibility, shifts the echo time of the interferometer, and...
Topics: Atomic Physics, Physics
Source: http://arxiv.org/abs/1703.06864
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4.0
Jun 30, 2018
06/18
by
Rosario González-Férez; Manuel Iñarrea; J. Pablo Salas; Peter Schmelcher
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We explore the classical dynamics of atoms in an optical dipole trap formed by two identical Gaussian beams propagating in perpendicular directions. The phase space is a mixture of regular and chaotic orbits, the later becoming dominant as the energy of the atoms increases. The trapping capabilities of these perpendicular Gaussian beams are investigated by considering an atomic ensemble in free motion. After a sudden turn on of the dipole trap, a certain fraction of atoms in the ensemble...
Topics: Physics, Atomic Physics
Source: http://arxiv.org/abs/1409.4707
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3.0
Jun 30, 2018
06/18
by
K. M. Daily; Javier von Stecher; Chris H. Greene
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We study the $2e^-2e^+$ equal-mass charge-neutral four-body system in the adiabatic hyperspherical framework. The lowest few adiabatic potentials are calculated for zero orbital angular momentum, positive parity, and charge conjugation symmetries. Propagating the R-matrix, the low-energy $s$-wave scattering lengths of the singlet-singlet and triplet-triplet spin configurations are calculated. Lastly, we calculate the S-matrix for energies above the ionic threshold to estimate the transition...
Topics: Physics, Atomic Physics
Source: http://arxiv.org/abs/1409.6518
4
4.0
Jun 30, 2018
06/18
by
I. M. Savukov; D. V. Filin
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Many applications are in need of accurate photoionization cross-sections, especially in the case of complex atoms. Configuration-interaction relativistic many-body perturbation theory (CI-RMBPT) that has been successful in predicting atomic energies, matrix elements between discrete states, and other properties is quite promising, but it has not been applied to photo-ionization problems owing to extra complications arising from continuum states. In this paper a method that will allow the...
Topics: Physics, Atomic Physics
Source: http://arxiv.org/abs/1410.1904
5
5.0
Jun 30, 2018
06/18
by
I. A. Maltsev; V. M. Shabaev; I. I. Tupitsyn; A. I. Bondarev; Y. S. Kozhedub; G. Plunien; Th. Stoehlker
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A new method for calculations of electron-positron pair-creation probabilities in low-energy heavy-ion collisions is developed. The approach is based on the propagation of all one-electron states via the numerical solving of the time-dependent Dirac equation in the monopole approximation. The electron wave functions are represented as finite sums of basis functions constructed from B-splines using the dual-kinetic-balance technique. The calculations of the created particle numbers and the...
Topics: Physics, Atomic Physics
Source: http://arxiv.org/abs/1412.5337
4
4.0
Jun 30, 2018
06/18
by
D. P. Dunseith; S. Truppe; R. J. Hendricks; B. E. Sauer; E. A. Hinds; M. R. Tarbutt
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We characterize a Fabry-Perot microwave cavity designed for trapping atoms and molecules at the antinode of a microwave field. The cavity is fed from a waveguide through a small coupling hole. Focussing on the compact resonant modes of the cavity, we measure how the electric field profile, the cavity quality factor, and the coupling efficiency, depend on the radius of the coupling hole. We measure how the quality factor depends on the temperature of the mirrors in the range from 77 to 293K. The...
Topics: Physics, Atomic Physics
Source: http://arxiv.org/abs/1409.2859
5
5.0
Jun 30, 2018
06/18
by
Brian Estey; Chenghui Yu; Holger Müller; Pei-Chen Kuan; Shau-Yu Lan
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We experimentally and theoretically study the diffraction phase of large-momentum transfer beam splitters in atom interferometers based on Bragg diffraction. We null the diffraction phase and increase the sensitivity of the interferometer by combining Bragg diffraction with Bloch oscillations. We demonstrate agreement between experiment and theory, and a 1500-fold reduction of the diffraction phase, limited by measurement noise. In addition to reduced systematic effects, our interferometer has...
Topics: Physics, Atomic Physics
Source: http://arxiv.org/abs/1410.8486
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4.0
Jun 30, 2018
06/18
by
Ingo Barth; Olga Smirnova
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We apply the time-dependent analytical R-matrix theory to develop a movie of hole motion in a Kr atom upon ionization by strong circularly polarized field. We find rich hole dynamics, ranging from rotation to swinging motion. The motion of the hole depends on the final energy and the spin of the photoelectron and can be controlled by the laser frequency and intensity. Crucially, hole rotation is a purely non-adiabatic effect, completely missing in the framework of quasistatic (adiabatic)...
Topics: Physics, Atomic Physics
Source: http://arxiv.org/abs/1408.6961
