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Mixed-frame formulations of radiation-hydrodynamics (RHD), where the radiation quantities are computed in an inertial frame but matter quantities are in a comoving frame, are advantageous because they admit algorithms that conserve energy…

Astrophysics of Galaxies · Physics 2024-11-25 Chong-Chong He , Benjamin D. Wibking , Mark R. Krumholz

We present the experimental realization and characterization of a Ramsey interferometer based on optically trapped ultracold potassium atoms, where one state is continuously coupled by an off-resonant laser field to a highly-excited Rydberg…

Atomic Physics · Physics 2019-02-13 A. Arias , G. Lochead , T. M. Wintermantel , S. Helmrich , S. Whitlock

We provide a new method to derive heavy element abundances based on the unique suite of nebular lines in the mid- to far-infrared (IR) range. Using grids of photo-ionisation models that cover a wide range in O/H and N/O abundances, and…

Astrophysics of Galaxies · Physics 2021-08-11 J. A. Fernández-Ontiveros , E. Pérez-Montero , J. M. Vílchez , R. Amorín , L. Spinoglio

Due to their affordable, low mass, and small dimensions, uncooled microbolometer-based thermal focal plane arrays (UC-FPAs) are useful for long-wave infrared (LWIR)imaging applications. However, in outdoor conditions typical in agricultural…

Image and Video Processing · Electrical Eng. & Systems 2025-03-05 Peretz Yafin , Nir Sochen , Iftach Klapp

Many exotic phenomena in strongly correlated electron systems emerge from the interplay between spin and motional degrees of freedom. For example, doping an antiferromagnet gives rise to interesting phases including pseudogap states and…

We present a ray tracing code to compute integrated cosmological observables on the fly in AMR N-body simulations. Unlike conventional ray tracing techniques, our code takes full advantage of the time and spatial resolution attained by the…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-23 Alexandre Barreira , Claudio Llinares , Sownak Bose , Baojiu Li

We describe a new method for comparing frame appearance in a frame-to-model 3-D mapping and tracking system using an low dynamic range (LDR) RGB-D camera which is robust to brightness changes caused by auto exposure. It is based on a…

Computer Vision and Pattern Recognition · Computer Science 2016-04-05 Shuda Li , Ankur Handa , Yang Zhang , Andrew Calway

The paper analyzes the absorption line profile at 21 cm for the hydrogen atom in the interstellar medium. The hydrogen atom is treated as a three-level system illuminated by a powerful light source at neighboring resonances corresponding to…

Atomic Physics · Physics 2018-11-05 D. Solovyev

Light-matter interacting quantum systems manifest strong correlations that lead to distinct cooperative spontaneous emissions of subradiance or superradiance. To demonstrate the essence of long-range correlations in such systems, we…

Quantum Physics · Physics 2022-05-31 C. Y. Lin , H. H. Jen

Gamma rays measured by the Fermi-LAT satellite tell us a lot about the processes taking place in high-energetic astrophysical objects. The fluxes coming from these objects are, however, extremely variable. Hence, gamma-ray light curves…

Instrumentation and Methods for Astrophysics · Physics 2025-02-13 Theo Glauch , Kristian Tchiorniy

Here we present our current updates of the gas-phase chemical reaction rates and molecular lines in the spectral synthesis code CLOUDY, and its implications in spectroscopic modelling of various astrophysical environments. We include energy…

Astrophysics of Galaxies · Physics 2022-08-03 Gargi Shaw , G. J. Ferland , M. Chatzikos

Non-LTE radiative transfer is a key tool for modern astrophysics: it is the means by which many key synthetic observables are produced, thus connecting simulations and observations. Radiative transfer models also inform our understanding of…

Solar and Stellar Astrophysics · Physics 2025-11-12 Christopher M. J. Osborne , Alexander Sannikov

Visualizing molecular transformations in real-time requires a structural retrieval method with {\AA}ngstr\"om spatial and femtosecond temporal atomic resolution. Imaging of hydrogen-containing molecules additionally requires an imaging…

We present a formulation for multigroup radiation hydrodynamics that is correct to order $O(v/c)$ using the comoving-frame approach and the flux-limited diffusion approximation. We describe a numerical algorithm for solving the system,…

Instrumentation and Methods for Astrophysics · Physics 2015-06-05 W. Zhang , L. Howell , A. Almgren , A. Burrows , J. Dolence , J. Bell

A numerical scheme is proposed for the solution of the three-dimensional radiative transfer equation with variable optical depth. We show that time-dependent ray tracing is an attractive choice for simulations of astrophysical ionization…

Astrophysics · Physics 2009-10-31 Alexei Razoumov , Douglas Scott

We study a modified Ramsey spectroscopy technique employing slowly decaying states for quantum metrology applications using dense ensembles. While closely positioned atoms exhibit superradiant collective decay and dipole-dipole induced…

Atomic Physics · Physics 2015-06-22 Laurin Ostermann , David Plankensteiner , Helmut Ritsch , Claudiu Genes

We describe a method to compute photon-matter interaction and atomic dynamics with X-ray lasers using a hybrid code based on classical molecular dynamics and collisional-radiative calculations. The forces between the atoms are dynamically…

Infrared hybridized detectors are widely used in astronomy, and their performance can be degraded by image persistence. This results in remnant images that can persist in the detector for many hours, contaminating any subsequent…

Instrumentation and Methods for Astrophysics · Physics 2019-09-04 Simon Tulloch , Elizabeth George

In recent years, the demand for hyperspectral imaging devices has grown significantly, driven by their ability of capturing high-resolution spectral information. Among the several possible optical designs for acquiring hyperspectral images,…

Image and Video Processing · Electrical Eng. & Systems 2023-06-06 Daniele Picone , Silvére Gousset , Mauro Dalla-Mura , Yann Ferrec , Etienne le-Coarer

Damped Lyman-$\alpha$ absorbers (DLAs) with molecular hydrogen have been probed in detail through both spectroscopic observations and numerical modelling. However, such H$_2$ absorbers are quite sparse at very high redshifts. We identify…

Astrophysics of Galaxies · Physics 2025-03-20 Aashiya Anitha Shaji , Katherine Rawlins , Pranshu Kurel
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