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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

Electromagnetic (EM) wave scattering in electrically large, irregularly shaped, environments is a common phenomenon. The deterministic, or first principles, study of this process is usually computationally expensive and the results exhibit…

Adaptation and Self-Organizing Systems · Physics 2023-06-21 Shukai Ma , Thomas M. Antonsen , Steven M. Anlage

A mass-conservative high-order unfitted finite element method for convection-diffusion equations in evolving domains is proposed. The space-time method presented in [P. Hansbo, M. G. Larson, S. Zahedi, Comput. Methods Appl. Mech. Engrg. 307…

Numerical Analysis · Mathematics 2024-05-01 Sebastian Myrbäck , Sara Zahedi

We present the results of computations performed with a new photoionisation-transfer code designed for hot Compton thick media. Presently the code solves the transfer of the continuum with the Accelerated Lambda Iteration method (ALI) and…

Astrophysics · Physics 2007-05-23 S. Coupé , M-C. Artru , S. Collin , B. Czerny , A-M. Dumont

We present a numerical method and computer code to calculate the radiative transfer and excitation of molecular lines. Formulating the Monte Carlo method from the viewpoint of cells rather than photons allows us to separate local and…

Astrophysics · Physics 2007-05-23 Michiel R. Hogerheijde , Floris F. S. van der Tak

We present a numerical code for radiation hydrodynamics designed as a module for the freely available PLUTO code. We adopt a gray approximation and include radiative transfer following a two-moment approach by imposing the M1 closure to the…

Earth and Planetary Astrophysics · Physics 2021-01-20 Julio David Melon Fuksman , Hubert Klahr , Mario Flock , Andrea Mignone

We extend the Finite-Difference Time-Domain method to treat dispersive magnetic media by incorporating magneto-optical effects through a frequency-dependent permittivity tensor. For benchmarking our method, we consider the light scattering…

A numerical scheme is described for including radiation in multi-dimensional general-relativistic conservative fluid dynamics codes. In this method, a covariant form of the M1 closure scheme is used to close the radiation moments, and the…

High Energy Astrophysical Phenomena · Physics 2013-01-16 Aleksander Sadowski , Ramesh Narayan , Alexander Tchekhovskoy , Yucong Zhu

A module for the ZEUS-2D code is described which may be used to solve the equations of radiation hydrodynamics to order unity in v/c, in the flux-limited diffusion (FLD) approximation. In this approximation, the tensor Eddington factor f…

Astrophysics · Physics 2009-11-06 N. J. Turner , J. M. Stone

As a universal quantum mechanical approach to the dynamical many-body problem, the time-dependent density functional theory (TDDFT) might be inadequate to describe crucial observables that rely on two-body evolution behavior, like the…

Computational Physics · Physics 2025-11-17 Jiong-Hang Liang , Yunfeng Xiong

The derivation of the time-dependent variational equations of the Multi-Configuration Time-Dependent Hartree (MCTDH) method for high-dimensional quantum propagation is revisited from the perspective of tangent space projection methods. In…

Chemical Physics · Physics 2018-09-27 Matteo Bonfanti , Irene Burghardt

We construct a model of cooperative superradiant emission from a highly relativistic multi-particle source. We revise an existing model of the literature for a relativistic two-level particle, and construct from it a Hamiltonian describing…

Quantum Physics · Physics 2023-01-18 Christopher Wyenberg , Fereshteh Rajabi , Martin Houde

Time-resolved spectroscopy provides the main tool for analyzing the dynamics of excitonic energy transfer in light-harvesting complexes. To infer time-scales and effective coupling parameters from experimental data requires to develop…

Chemical Physics · Physics 2018-11-28 Tobias Kramer , Mirta Rodriguez , Yaroslav Zelinskyy

We present a time-dependent extension of logarithmic perturbation theory for nonrelativistic quantum dynamics governed by the Schr\"odinger equation, in which the logarithm of the wave function is expanded in powers of a coupling constant.…

Quantum Physics · Physics 2026-04-17 Juan Carlos del Valle , Paul Bergold , Karolina Kropielnicka

Efficient time integration schemes are necessary to capture the complex processes involved in atmospheric flows over long periods of time. In this work, we propose a high-order, implicit-explicit numerical scheme that combines Multi-Level…

Numerical Analysis · Mathematics 2018-10-22 Francois Hamon , Martin Schreiber , Michael Minion

We develop a new numerical scheme for solving the radiative transfer equation in a spherically symmetric system. This scheme does not rely on any kind of diffusion approximation and it is accurate for optically thin, thick, and intermediate…

Instrumentation and Methods for Astrophysics · Physics 2018-05-31 Torsten Stamer , Shu-ichiro Inutsuka

We develop a neutrino transfer code for core-collapse simulations, that directly solves the multidimensional Boltzmann equations in full general relativity. We employ the discrete ordinate method, which discretizes the six dimensional phase…

Context: Knowledge about hot, massive stars is usually inferred from quantitative spectroscopy. To analyse non-spherical phenomena, the existing 1D codes must be extended to higher dimensions, and corresponding tools need to be developed.…

Solar and Stellar Astrophysics · Physics 2019-12-25 L. Hennicker , J. Puls , N. D. Kee , J. O. Sundqvist

We have developed a general purpose dust radiative transfer code for an axisymmetric system, 2-Dust, motivated by the recent increasing availability of high-resolution images of circumstellar dust shells at various wavelengths. This code…

Astrophysics · Physics 2009-11-07 Toshiya Ueta , Margaret Meixner

In this contribution, we extend our framework for analyzing and visualizing correlated many-electron dynamics to non-variational, highly scalable electronic structure method. Specifically, an explicitly time-dependent electronic wave packet…

Chemical Physics · Physics 2017-04-27 Gunter Hermann , Vincent Pohl , Jean Christophe Tremblay