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This manuscript presents verification cases that are developed to study the electrothermal instability (ETI). Specific verification cases are included to ensure that the unit physics components necessary to model the ETI are accurate,…

Plasma Physics · Physics 2021-03-10 R. L. Masti , C. L. Ellison , J. R. King , P. H. Stoltz , B. Srinivasan

Non-rotating neutron stars are generally treated in theoretical studies as perfect spheres. Such a treatment, however, may not be correct if strong magnetic fields are present (such as for magnetars) and/or the pressure of the matter in the…

Solar and Stellar Astrophysics · Physics 2015-04-14 O. Zubairi , W. Spinella , A. Romero , R. Mellinger , F. Weber , M. Orsaria , G. Contrera

The measurement of stellar properties such as chemical compositions, masses and ages, through stellar spectra, is a fundamental problem in astrophysics. Progress in the understanding, calculation and measurement of atomic properties and…

Solar and Stellar Astrophysics · Physics 2016-06-08 Paul S. Barklem

Ultracold atomic physics experiments offer a nearly ideal context for the investigation of quantum systems far from equilibrium. We describe three related emerging directions of research into extreme non-equilibrium phenomena in atom traps:…

This work describes extensions to existing level-set algorithms developed for application within the field of Atom Probe Tomography (APT). We present a new simulation tool for the simulation of 3D tomographic volumes, using advanced level…

Computational Physics · Physics 2018-02-28 Daniel Haley , Paul A. J. Bagot , Michael P. Moody

We present a model which describes coherent and incoherent processes in continuous-variable atom-light interfaces. We assume Gaussian states for light and atoms and formulate the system dynamics in terms of first and second moments of the…

Quantum Physics · Physics 2008-02-22 M. Koschorreck , M. W. Mitchell

The inference of the underlying state of the plasma in the solar chromosphere remains extremely challenging because of the nonlocal character of the observed radiation and plasma conditions in this layer. Inversion methods allow us to…

Solar and Stellar Astrophysics · Physics 2019-03-06 J. de la Cruz Rodríguez , J. Leenaarts , S. Danilovic , H. Uitenbroek

This paper deals with a non-parametric problem coming from physics, namely quantum tomography. That consists in determining the quantum state of a mode of light through a homodyne measurement. We apply several model selection procedures:…

Statistics Theory · Mathematics 2007-12-19 Jonas Kahn

Radiative opacity is an important quantity in the modeling of stellar structure and evolution. In the present work we recall the role of opacity in the interpretation of pulsations of different kinds of stars. The detailed opacity code…

Solar and Stellar Astrophysics · Physics 2022-09-26 Jean-Christophe Pain , Franck Gilleron , Maxime Comet

Quantum link models provide an alternative non-perturbative formulation of Abelian and non-Abelian lattice gauge theories. They are ideally suited for quantum simulation, for example, using ultracold atoms in an optical lattice. This holds…

High Energy Physics - Theory · Physics 2015-06-23 Uwe-Jens Wiese

We test the accuracy of the ALI method, widely used in stellar atmosphere modelling, by solving exactly a standard radiative transfer problem in plane-parallel geometry. Some recommendations are given for a practical use of this method.

Astrophysics · Physics 2007-05-23 L. Chevallier , F. Paletou , B. Rutily

Lattice models or structures are geometrical objects with mathematical forms, that are used to represent physical systems. They have been used widely in diverse fields, namely, in condensed matter physics, to study degrees of freedom of…

Quantum Physics · Physics 2024-06-04 Kalyan Dasgupta

We develop a scheme for quantum computation with neutral atoms, based on the concept of "marker" atoms, i.e., auxiliary atoms that can be efficiently transported in state-independent periodic external traps to operate quantum gates between…

Quantum Physics · Physics 2009-11-10 T. Calarco , U. Dorner , P. Julienne , C. Williams , P. Zoller

Radio-frequency-driven atmospheric pressure plasma jets (RF APPJs) play an essential role in many technological applications. This work studies the characteristics of these discharges in the so-called non-neutral regime where the…

Plasma Physics · Physics 2021-09-21 Maximilian Klich , Sebastian Wilczek , Zoltan Donko , Ralf Peter Brinkmann

In this report I attempt to outline the process of developing and building an absorption imaging system capable of imaging ultracold atoms. In the theory section I will discuss the elements required to estimate the atom number and derive…

Instrumentation and Detectors · Physics 2012-09-20 Tadas Pyragius

The tight binding model is a minimal electronic structure model for molecular modelling and simulation. We show that the total energy in this model can be decomposed into site energies, that is, into contributions from each atomic site…

Numerical Analysis · Mathematics 2015-06-19 Huajie Chen , Christoph Ortner

Modeling the dynamics of most astrophysical structures requires an adequate description of the radiation-matter interaction. Several numerical (magneto)hydrodynamics codes were upgraded with a radiation module to fulfill this request.…

Instrumentation and Methods for Astrophysics · Physics 2019-11-06 Salvatore Colombo , Laurent Ibgui , Salvatore Orlando , Raphael Rodriguez , Guadalupe Espinosa , Matthias González , Chantal Stehlé , Giovanni Peres

A hidden symmetry of the nonlinear wave equation is exploited to analyse the propagation of paraxial and uniform atom-laser beams in time-independent, quadratic and cylindrical potentials varying smoothly along the propagation axis. The…

Quantum Physics · Physics 2015-05-13 François Impens

We present a detailed study of the non-Local Thermodynamic Equilibrium (non-LTE) formation of the high-excitation neutral oxygen 777 nm triplet in MARCS model atmospheres representative of late-type stars with spectral types F to K. We…

Solar and Stellar Astrophysics · Physics 2015-05-13 D. Fabbian , M. Asplund , P. S. Barklem , M. Carlsson , D. Kiselman

Dynamic power system models are instrumental in real-time stability, monitoring, and control. Such models are traditionally posed as systems of nonlinear differential algebraic equations (DAEs): the dynamical part models generator…

Systems and Control · Electrical Eng. & Systems 2024-02-02 Mohamad H. Kazma , Ahmad F. Taha