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In previous papers of this series, we presented a formalism able to account for both statistical equilibrium of a multilevel atom and coherent and incoherent scatterings (partial redistribution). aims: This paper provides theoretical…

Solar and Stellar Astrophysics · Physics 2017-11-15 V. Bommier

Optical properties of materials related to light absorption and scattering are explained by the excitation of electrons. The Bethe-Salpeter equation is the state-of-the-art approach to describe these processes from first principles (ab…

Numerical Analysis · Mathematics 2020-08-21 Peter Benner , Carolin Penke

We describe a general radiative equilibrium and temperature correction procedure for use in Monte Carlo radiation transfer codes with sources of temperature-independent opacity, such as astrophysical dust. The technique utilizes the fact…

Astrophysics · Physics 2010-04-08 J. E. Bjorkman , Kenneth Wood

Neutron capture cross sections of unstable isotopes are important for neutron-induced nucleosynthesis as well as for technological applications. A combination of a radioactive beam facility, an ion storage ring and a high flux reactor would…

In recent years, contour-based eigensolvers have emerged as a standard approach for the solution of large and sparse eigenvalue problems. Building upon recent performance improvements through non-linear least square optimization of…

Numerical Analysis · Mathematics 2021-12-14 Konrad Kollnig , Paolo Bientinesi , Edoardo Di Napoli

Controlling multiple wave properties simultaneously poses a key challenge in coherent control of wave transport. We present a theory for joint coherent control of transmission, reflection, and absorption in linear systems. We prove that the…

Optics · Physics 2025-11-10 Shiyu Li , Dongha Kim , Shanhui Fan , Cheng Guo

We describe optimized coherent control methods for two-photon transitions in atoms of a ladder-type three-state energy configuration. Our approach is based on the spatial coherent control scheme which utilizes counter-propagating ultrashort…

Atomic Physics · Physics 2015-10-28 Woojun Lee , Hyosub Kim , Kyungtae Kim , Jaewook Ahn

In the field of deep learning based computer vision, the development of deep object detection has led to unique paradigms (e.g., two-stage or set-based) and architectures (e.g., Faster-RCNN or DETR) which enable outstanding performance on…

Computer Vision and Pattern Recognition · Computer Science 2022-10-07 Denis Huseljic , Marek Herde , Mehmet Muejde , Bernhard Sick

This paper presents a new fast and robust algorithm that provides fuel-optimal impulsive control input sequences that drive a linear time-variant system to a desired state at a specified time. This algorithm is applicable to a broad class…

Optimization and Control · Mathematics 2020-10-06 Adam W. Koenig , Simone D'Amico

Modeling of dynamic processes in nuclear reactors is carried out, mainly, on the basis of the multigroup diffusion approximation for the neutron flux. The basic model includes a multidimensional set of coupled parabolic equations and…

Computational Engineering, Finance, and Science · Computer Science 2017-06-19 Alexander V. Avvakumov , Valery F. Strizhov , Petr N. Vabishchevich , Alexander O. Vasilev

We consider the geometric optics problem of finding a system of two reflectors that transform a spherical wavefront into a beam of parallel rays with prescribed intensity distribution. Using techniques from optimal transportation theory, it…

Numerical Analysis · Mathematics 2011-11-08 Tilmann Glimm , Nick Henscheid

In control theory, typically a nominal model is assumed based on which an optimal control is designed and then applied to an actual (true) system. This gives rise to the problem of performance loss due to the mismatch between the true model…

Optimization and Control · Mathematics 2023-09-19 Somnath Pradhan , Serdar Yuksel

An ab-initio description of atomic nuclei that solves the nuclear many-body problem for realistic nuclear forces is expected to possess a high degree of predictive power. In this contribution we treat the main obstacle, namely the…

Nuclear Theory · Physics 2017-08-23 Hans Feldmeier , Thomas Neff , Robert Roth

In this paper, a new type of multi-level correction scheme is proposed for solving eigenvalue problems by finite element method. With this new scheme, the accuracy of eigenpair approximations can be improved after each correction step which…

Numerical Analysis · Mathematics 2011-07-04 Qun Lin , Hehu Xie

Kernel methods are successful approaches for different machine learning problems. This success is mainly rooted in using feature maps and kernel matrices. Some methods rely on the eigenvalues/eigenvectors of the kernel matrix, while for…

Machine Learning · Computer Science 2012-02-20 Nima Reyhani , Hideitsu Hino , Ricardo Vigario

In this paper, we give a numerical analysis for the transmission eigenvalue problem by the finite element method. A type of multilevel correction method is proposed to solve the transmission eigenvalue problem. The multilevel correction…

Numerical Analysis · Mathematics 2016-04-26 Hehu Xie , Xinming Wu

Many algorithms feature an iterative loop that converges to the result of interest. The numerical operations in such algorithms are generally implemented using finite-precision arithmetic, either fixed- or floating-point, most of which…

Hardware Architecture · Computer Science 2019-10-02 He Li , James J. Davis , John Wickerson , George A. Constantinides

Recently, the problem of boundary stabilization and estimation for unstable linear constant-coefficient reaction-diffusion equation on n-balls (in particular, disks and spheres) has been solved by means of the backstepping method. However,…

Optimization and Control · Mathematics 2022-07-21 Rafael Vazquez , Jing Zhang , Jie Qi , Miroslav Krstic

We outline inconsistencies in presently used models for high energy nuclear scattering, which make their application quite unreliable. Many "successes" are essentially based on an artificial freedom of parameters, which does not exist when…

High Energy Physics - Phenomenology · Physics 2009-11-07 K. Werner , H. J. Drescher , S. Ostapchenko , T. Pierog

Properly designed control has been shown to be particularly advantageous for improving AQC accuracy and time complexity scaling. Here, an \emph{in situ} quantum control optimization protocol is developed to indirectly optimize state…

Quantum Physics · Physics 2019-06-12 Gregory Quiroz
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