# Atomic Physics

## New submissions

[ total of 11 entries: 1-11 ]
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### New submissions for Tue, 20 Mar 18

[1]
Title: First Calorimetric Measurement of Electron Capture in ${}^{193}$Pt with a Transition Edge Sensor
Comments: 17th International Workshop on Low Temperature Detectors
Subjects: Atomic Physics (physics.atom-ph); Instrumentation and Detectors (physics.ins-det)

The neutrino mass can be extracted from a high statistics, high resolution calorimetric spectrum of electron capture in ${}^{163}$Ho. In order to better understand the shape of the calorimetric electron capture spectrum, a second isotope was measured with a close to ideal absorber-source configuration. ${}^{193}$Pt was created by irradiating a ${}^{192}$Pt-enriched platinum foil in a nuclear reactor. This Pt-in-Pt absorber was designed to have a nearly ideal absorber-source configuration. The measured ${}^{193}$Pt calorimetric electron-capture spectrum provides an independent check on the corresponding theoretical calculations, which have thus far been compared only for ${}^{163}$Ho. The first experimental and theoretically-calculated spectra from this ${}^{193}$Pt-in-Pt absorber are presented and overlaid for preliminary comparison of theory with experiment.

[2]
Title: Measuring fluorescence by observing field quadrature noise
Subjects: Atomic Physics (physics.atom-ph)

We perform balanced homodyne detection of the electromagnetic field in a single-mode tapered optical nanofiber surrounded by rubidium atoms in a magneto-optical trap. Resonant fluorescence of atoms into the nanofiber mode manifests itself as increased quantum noise of the field quadratures. The autocorrelation function of the homodyne detector's output photocurrent exhibits exponential fall-off with a decay time constant of $26.3\pm 0.6$ ns, which is consistent with the theoretical expectation under our experimental conditions. To our knowledge, this is the first experiment in which fluorescence has been observed and measured by balanced optical homodyne detection.

[3]
Title: Highly charged ions: optical clocks and applications in fundamental physics
Comments: 53 pages, 16 figures, submitted to RMP
Subjects: Atomic Physics (physics.atom-ph)

Recent developments in frequency metrology and optical clocks have been based on electronic transitions in atoms and singly charged ions as references. These systems have enabled relative frequency uncertainties at a level of a few parts in $10^{-18}$. This accomplishment not only allows for extremely accurate time and frequency measurements, but also to probe our understanding of fundamental physics, such as variation of fundamental constants, violation of the local Lorentz invariance, and forces beyond the Standard Model of Physics. In addition, novel clocks are driving the development of sophisticated technical applications. Crucial for applications of clocks in fundamental physics are a high sensitivity to effects beyond the Standard Model and Einstein's Theory of Relativity and a small frequency uncertainty of the clock. Highly charged ions offer both. They have been proposed as highly accurate clocks, since they possess optical transitions which can be extremely narrow and less sensitive to external perturbations compared to current atomic clock species. The selection of highly charged ions in different charge states offers narrow transitions that are among the most sensitive ones for a change in the fine-structure constant and the electron-to-proton mass ratio, as well as other new physics effects. Recent advances in trapping and sympathetic cooling of highly charged ions will in the future enable high accuracy optical spectroscopy. Progress in calculating the properties of selected highly charged ions has allowed the evaluation of systematic shifts and the prediction of the sensitivity to the "new physics" effects. This article reviews the current status of theory and experiment in the field.

[4]
Title: Development of co-located ${}^{129}$Xe and ${}^{131}$Xe nuclear spin masers with external feedback scheme
Journal-ref: Phys. Lett. A 382, 588-594 (2018)
Subjects: Atomic Physics (physics.atom-ph)

We report on the operation of co-located ${}^{129}$Xe and ${}^{131}$Xe nuclear spin masers with an external feedback scheme, and discuss the use of ${}^{131}$Xe as a comagnetometer in measurements of the ${}^{129}$Xe spin precession frequency. By applying a correction based on the observed change in the ${}^{131}$Xe frequency, the frequency instability due to magnetic field and cell temperature drifts are eliminated by two orders of magnitude. The frequency precision of 6.2 $\mu$Hz is obtained for a 10$^4$ s averaging time, suggesting the possibility of future improvement to $\approx$ 1 nHz by improving the signal-to-noise ratio of the observation.

### Cross-lists for Tue, 20 Mar 18

[5]  arXiv:1803.05333 (cross-list from physics.atm-clus) [pdf, ps, other]
Title: Observability of the Efimov spectrum in an electron-atom-atom system
Subjects: Atomic and Molecular Clusters (physics.atm-clus); Quantum Gases (cond-mat.quant-gas); Atomic Physics (physics.atom-ph)

The bound states of a system consisting of two heavy identical atoms and one light electron interacting through the finite-range pairwise potentials are explored, focusing on their dependence on the electron-atom scattering length. In the case of an exact resonance in the electron-atom interaction, the binding energy of an electron yields an effective $1/r^{2}$ potential for the relative motion of the atoms; One major finding is a universal potential that depends on the polarization length which goes beyond the Efimov region. An analytic expression for that potential is extracted from numerical calculations. The spectrum of the e+Rb+Rb system produced by the electron-atom polarization interaction exhibits three main sections, a non-universal transition region, a quasi-Efimov region, and a densely packed Efimov region.

[6]  arXiv:1803.06338 (cross-list from cond-mat.quant-gas) [pdf, other]
Title: Elliptic flow in a strongly-interacting normal Bose gas
Subjects: Quantum Gases (cond-mat.quant-gas); Statistical Mechanics (cond-mat.stat-mech); Atomic Physics (physics.atom-ph); Plasma Physics (physics.plasm-ph); Quantum Physics (quant-ph)

We study the anisotropic, elliptic expansion of a thermal atomic Bose gas released from an anisotropic trapping potential, for a wide range of interaction strengths across a Feshbach resonance. We show that in our system this hydrodynamic phenomenon is for all interaction strengths fully described by a microscopic kinetic model with no free parameters. The success of this description crucially relies on taking into account the reduced thermalising power of elastic collisions in a strongly interacting gas, for which we derive an analytical theory. We also perform time-resolved measurements that directly reveal the dynamics of the energy transfer between the different expansion axes.

[7]  arXiv:1803.06475 (cross-list from cond-mat.quant-gas) [pdf, other]
Title: Magneto-optical trapping of optically pumped metastable europium
Subjects: Quantum Gases (cond-mat.quant-gas); Atomic Physics (physics.atom-ph)

The laser cooling and trapping of europium is demonstrated herein. The atoms are optically pumped to a metastable state and then loaded from an atomic-beam source via conventional Zeeman slowing and magneto-optical trapping techniques using a J=13/2 <--> J=15/2 quasi-cyclic transition. The trapped populations contained up to 1x10^7 atoms, and the density-dependent loss rate is estimated as 1x10^-10 cm^3/s from the non-exponential loss of atoms at high densities. We also observed leakage out of the quasi-cyclic transition to the J=9/2 and 11/2 metastable states, which is adequate to pump the laser-cooled atoms back to the ground state.

[8]  arXiv:1803.07004 (cross-list from nlin.CD) [pdf, other]
Title: Capturing photoelectron motion with guiding fictitious particles
Comments: Physical Review Letters, American Physical Society, In press
Subjects: Chaotic Dynamics (nlin.CD); Atomic Physics (physics.atom-ph)

Photoelectron momentum distributions (PMDs) from atoms and molecules undergo qualitative changes as laser parameters are varied. We present a model to interpret the shape of the PMDs. The electron's motion is guided by a fictitious particle in our model, clearly characterizing two distinct dynamical behaviors: direct ionization and rescattering. As laser ellipticity is varied, our model reproduces the bifurcation in the PMDs seen in experiments.

### Replacements for Tue, 20 Mar 18

[9]  arXiv:1712.08275 (replaced) [pdf, ps, other]
Title: Ultracold anions for high-precision antihydrogen experiments
Title: Scaling Law for Three-body Collisions in Identical Fermions with $p$-wave Interactions
Title: Characterization of the hyperfine interaction of the excited $^5$D$_0$ state of Eu$^{3+}$:Y$_2$SiO$_5$