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The cold field electron emission from metallic nanowall array is investigated theoretically. Via conformal mapping method, analytic formulas of tunneling barrier, edge field enhancement factor, transmission coefficient, and area emission…

Mesoscale and Nanoscale Physics · Physics 2011-11-15 Xizhou Qin , Weiliang Wang , Zhibing Li

Ultracold atom-based electron sources have recently been proposed as an alternative to the conventional photo-injectors or thermionic electron guns widely used in modern particle accelerators. The advantages of ultracold atom-based electron…

Accelerator Physics · Physics 2015-06-19 G. Xia , M. Harvey , A. J. Murray , L. Bellan , W. Bertsche , R. B. Appleby , O. Mete , S. Chattopadhyay

Field ion microscopy (FIM) allows to image individual surface atoms by exploiting the effect of an intense electric field. Widespread use of atomic resolution imaging by FIM has been hampered by a lack of efficient image processing/data…

This paper presents a new acoustic emission (AE) source localization for isotropic plates with reflecting boundaries. This approach that has no blind spot leverages multimodal edge reflections to identify AE sources with only a single…

Applied Physics · Physics 2017-07-04 Arvin Ebrahimkhanlou , Salvatore Salamone

A first-principles approach is introduced to calculate electron field emission characteristics of nanostructures, based on the nonequilibrium Green function technique combined with the density functional theory. The method employs…

Mesoscale and Nanoscale Physics · Physics 2014-11-19 Hyon-Chol Choe , Nam-Hyok Kim , Hyok Kim , Song-Jin Im

We have developed MICROMEGAS (MICRO MEsh GASeous) detectors for detecting {\alpha} particles emitted from an 241-Am standard source. The voltage applied to the ionization region of the detector is optimized for stable operation at room…

Instrumentation and Detectors · Physics 2016-05-25 Do Yoon Kim , Cheolmin Ham , Jae Won Shin , Tae-Sun Park , Seung-Woo Hong , Samuel Andriamonje , Yacine Kadi , Claudio Tenreiro

The NL-$e$EDM experiment searches for a non-zero electric dipole moment of the electron $d_e$ ($e$EDM) in the ground state of barium monofluoride (BaF). A beam of BaF from a supersonic expansion source is probed with the spin precession…

The method of maximum likelihood estimation (MLE) is a widely used statistical approach for estimating the values of one or more unknown parameters of a probabilistic model based on observed data. In this tutorial, I briefly review the…

Data Analysis, Statistics and Probability · Physics 2018-12-03 Anthony Vella

The atomic spectra and structure of the open d- and f-shell elements are extremely complex, where tens of thousands of transitions between fine structure energy levels can be observed as spectral lines across the infrared and UV per…

Atomic Physics · Physics 2025-01-23 M. Ding , S. Z. J. Lim , X. Yu , C. P. Clear , J. C. Pickering

Narrow Fe K$\alpha$ fluorescent emission lines arising at $\sim$kpc-scale separations from the nucleus have only been detected in a few AGN. The detections require that the extended line emission be spatially resolved and sufficiently…

High Energy Astrophysical Phenomena · Physics 2023-12-04 P. Tzanavaris , T. Yaqoob , S. LaMassa

Force-free electrodynamics (FFE) is a closed set of equations for the electromagnetic field of a magnetically dominated plasma. There are strong arguments for the existence of force-free plasmas near pulsars and active black holes, but FFE…

High Energy Physics - Theory · Physics 2019-05-22 Samuel E. Gralla , Nabil Iqbal

We used numerical simulations based on the finite element method (FEM) to calculate both the amplitude and phase information of the scattered electric field from random rough surfaces, which can be directly compared to ellipsometric…

Computational Physics · Physics 2019-02-27 B. Fodor , P. Kozma , S. Burger , M. Fried , P. Petrik

In this article, the piecewise-linear finite element method (FEM) is applied to approximate the solution of time-fractional diffusion equations on bounded convex domains. Standard energy arguments do not provide satisfactory results for…

Numerical Analysis · Mathematics 2018-11-06 Samir Karaa , Kassem Mustapha , Amiya K. Pani

This paper introduces an accurate edge-based smoothed finite element method (ES-FEM) for electromagnetic analysis for both two dimensional cylindrical and three dimensional cartesian systems, which shows much better performance in terms of…

Computational Engineering, Finance, and Science · Computer Science 2019-10-30 Yangfan Zhang , Pengfei Wang , Wenping Li , Shunchuan Yang

Miniature atomic beams can provide new functionalities for atom based sensing instruments such as atomic clocks and interferometers. We recently demonstrated a planar silicon device for generating well-collimated thermal atomic beams [Nat…

Atomic Physics · Physics 2020-07-01 Chao Li , Bochao Wei , Xiao Chai , Jeremy Yang , Anosh Daruwalla , Farrokh Ayazi , C. Raman

We present a formula to evaluate the spontaneous emission spectra of an atom in contact with a radiation field with non-Markovian effects. This formula is written in terms of a two-time correlation of system observables and the…

Quantum Physics · Physics 2017-08-17 Ines de Vega , Daniel Alonso

We investigated the optical FeII emission in a sample of about 215 low-redshift AGN (quasars and luminous Seyfert 1 galaxies). We find that a scaled and broadened FeII template based on the I Zw 1 spectrum can satisfactorily model the FeII…

Astrophysics · Physics 2007-05-23 C. Bongardo , R. Zamanov , P. Marziani , M. Calvani , J. W. Sulentic

The field emission of crystalline AAA graphite is studied within a simple analytical approach with account of the exact dispersion relation near the Fermi level. The emission current is calculated for two crystal orientations with respect…

Other Condensed Matter · Physics 2009-11-13 V. L. Katkov , V. A. Osipov

The ability to characterize static and time-dependent electric fields in situ is an important prerequisite for quantum-optics experiments with atoms close to surfaces. Especially in experiments which aim at coupling Rydberg atoms to the…

Quantum Physics · Physics 2016-01-05 T. Thiele , J. Deiglmayr , M. Stammeier , J. -A. Agner , H. Schmutz , F. Merkt , A. Wallraff

We propose an energy-stable parametric finite element method (ES-PFEM) to discretize the motion of a closed curve under surface diffusion with an anisotropic surface energy $\gamma(\theta)$ -- anisotropic surface diffusion -- in two…

Numerical Analysis · Mathematics 2021-10-26 Yifei Li , Weizhu Bao