English
Related papers

Related papers: R-Matrix calculations for opacities: I. Methodolog…

200 papers

Wavefront shaping systems aim to image deep into scattering tissue by reshaping incoming and outgoing light to correct aberrations caused by tissue inhomogeneity However, the desired modulation depends on the unknown tissue structure and…

Optics · Physics 2026-01-14 Sagi Monin , Marina Alterman , Anat Levin

Plasma models built on extensive atomic data are essential to interpreting the observed cosmic spectra. H-like Lyman series and He-like triplets observable in the X-ray band are powerful diagnostic lines to measure the physical properties…

Atomic Physics · Physics 2022-12-14 Junjie Mao , G. Del Zanna , Liyi Gu , Chunyu Zhang , N. R. Badnell

Diagrammatic techniques to compute perturbatively the spectral properties of Euclidean Random Matrices in the high-density regime are introduced and discussed in detail. Such techniques are developed in two alternative and very different…

Disordered Systems and Neural Networks · Physics 2011-08-31 T. S. Grigera , V. Martin-Mayor , G. Parisi , P. Urbani , P. Verrocchio

We optimize the matrix representation of the nucleon-pair approximation (NPA) of the nuclear shell model. The NPA is a widely adopted truncation approach of the nuclear shell model and proves to be effective in describing low-lying states…

Nuclear Theory · Physics 2022-01-27 Y. Lei , Y. Lu

We report on experimentally observed addition, subtraction and cancellation of orbital angular momentum (OAM) in the process of parametric four-wave mixing that results in frequency up- and down-converted emission in Rb vapour. Specific…

Advances in numerical optimization have supported breakthroughs in several areas of signal processing. This paper focuses on the recent enhanced variants of the proximal gradient numerical optimization algorithm, which combine quasi-Newton…

Signal Processing · Electrical Eng. & Systems 2020-01-28 Niccolò Antonello , Lorenzo Stella , Panagiotis Patrinos , Toon van Waterschoot

Reduced density matrix functional theory (RDMFT) calculations are usually implemented in a decoupled manner, where the orbital and occupation optimizations are repeated alternately. Typically, orbital updates are performed using the unitary…

Chemical Physics · Physics 2024-09-04 Yi-Fan Yao , Neil Qiang Su

The optimization of an optical system benefits greatly from a study of its aberrations and an identification of each of its elements' contribution to the overall aberration figures. The matrix formalism developed by one of the authors was…

General Physics · Physics 2009-11-10 Jose B. Almeida

The Density Matrix Renormalization Group (DMRG) has become a powerful numerical method that can be applied to low-dimensional strongly correlated fermionic and bosonic systems. It allows for a very precise calculation of static, dynamic and…

Condensed Matter · Physics 2007-05-23 Karen Hallberg

We propose a wave operator method to calculate eigenvalues and eigenvectors of large parameter-dependent matrices, using an adaptative active subspace. We consider a hamiltonian which depends on external adjustable or adiabatic parameters,…

Computational Physics · Physics 2020-05-29 Arnaud Leclerc , Georges Jolicard

Prior to recombination photons, electrons, and atomic nuclei rapidly scattered and behaved, almost, like a single tightly-coupled photon-baryon plasma. We investigate here the accuracy of the tight-coupling approximation commonly used to…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 Francis-Yan Cyr-Racine , Kris Sigurdson

This paper proposes a Riemannian Multiobjective Proximal Gradient Method (RMPGM) for composite optimization problems on manifolds. Unlike scalarization-based approaches, the proposed framework directly handles vector-valued objectives and…

Optimization and Control · Mathematics 2026-05-19 Kangming Chen

The model for the Planck-mean dust opacity $\kappa_{P}$ given in Appendix C of the STARFORGE simulations methods paper does not extrapolate well to low radiation temperature $T_{\rm rad}$, so we provide an updated calculation suitable for…

Ab initio calculations including relativistic effects employing the Breit-Pauli R-matrix (BPRM) method are reported for fine structure energy levels and oscillator strengths upto n = 10 and 0.leq. l .leq.9 for 15 Li-like ions: C IV, N V, O…

Astrophysics · Physics 2009-11-07 Sultana N. Nahar

A randomized algorithm for computing a data sparse representation of a given rank structured matrix $A$ (a.k.a. an $H$-matrix) is presented. The algorithm draws on the randomized singular value decomposition (RSVD), and operates under the…

Numerical Analysis · Mathematics 2024-06-25 James Levitt , Per-Gunnar Martinsson

In the process of parametric optical image amplification, images are formed at new frequencies in addition to the amplified original image. We show that the parametric multiplexing of optical images can be used to produce an image with…

Quantum Physics · Physics 2019-03-27 D. A. Balakin , A. S. Chirkin

The planned measurement of optical resonances in singly-ionised lawrencium (Z = 103) requires accurate theoretical predictions to narrow the search window. We present high-precision, ab initio calculations of the electronic spectra of…

Atomic Physics · Physics 2019-12-18 E. V. Kahl , J. C. Berengut , M. Laatiaoui , E. Eliav , A. Borschevsky

We present a theory of linear optical constants based on a single-particle density matrix and implemented in an extension of the real-space multiple scattering code FEFF. This approach avoids the need to compute wave-functions explicitly,…

Materials Science · Physics 2015-05-13 M. P. Prange , J. J. Rehr , G. Rivas , J. J. Kas , John W. Lawson

We describe a generalized algorithm for evaluating the steady-state solution of the density matrix equation of motion, for the pump-probe scheme, when two fields oscillating at different frequencies couple the same set of atomic transitions…

Quantum Physics · Physics 2024-01-31 Zifan Zhou , Yael Sternfeld , Jacob Scheuer , Selim M. Shahriar

Optical orthogonal frequency-division multiplexing (OFDM) and probabilistic constellation shaping (PCS) have emerged as powerful techniques to enhance the performance of optical wireless communications (OWC) systems. While PCS improves…

Systems and Control · Electrical Eng. & Systems 2025-07-11 Thanh V. Pham , Susumu Ishihara
‹ Prev 1 8 9 10 Next ›