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A quantum theory of dispersion for an inhomogeneous solid is obtained, from a starting point of multipolar coupled atoms interacting with an electromagnetic field. The dispersion relations obtained are equivalent to the standard classical…

Quantum Physics · Physics 2009-10-31 P. D. Drummond , M. Hillery

Self-similar solutions of the coherent diffusion equation are derived and measured. The set of real similarity solutions is generalized by the introduction of a nonuniform phase surface, based on the elegant Gaussian modes of optical…

Quantum Physics · Physics 2015-05-19 O. Firstenberg , P. London , D. Yankelev , R. Pugatch , M. Shuker , N. Davidson

We use a concept of weak asymptotic solution for homogeneous as well as non-homogeneous fractional advection dispersion type equations. Using Legendre scaling functions as basis, a numerical method based on Galerkin approximation is…

Numerical Analysis · Mathematics 2015-05-01 Harendra Singh , Manas Ranjan Sahoo , Om Prakash Singh

Optical-model potentials (OMPs) are critical ingredients for basic and applied nuclear physics. Present-day computational capabilities allow us to generate data-driven nucleon-nucleus OMPs that are non-local and exactly dispersive (as…

This paper investigates the spectral structure, numerical dispersion, and observability of fully discrete approximations of the one-dimensional wave equation by $P^k$ (local) discontinuous Galerkin methods. Characterizing the coupled…

Optimization and Control · Mathematics 2026-05-21 Yunzhang Li , Xiaoyang Wang , Enrique Zuazua

Models of neutron stars are considered in the case of a uniform density distribution. An algebraic equation, valid for any equation of state, is obtained. This equation allows one to find the approximate mass of a star of a given density…

High Energy Astrophysical Phenomena · Physics 2023-11-14 G. S. Bisnovatyi-Kogan , E. A. Patraman

Predictions of nuclear models guide the design of nuclear facilities to ensure their safe and efficient operation. Because nuclear models often do not perfectly reproduce available experimental data, decisions based on their predictions may…

Nuclear Theory · Physics 2018-11-22 Georg Schnabel

A mean-field model with a generalized pairing interaction that accounts for neutron-proton pairing is presented. Both the BCS as well as number-projected solutions of the model are presented. For the latter case the Lipkin-Nogami projection…

Nuclear Theory · Physics 2009-11-06 W. Satula , R. Wyss

An exact, number-conserving solution to the generalized, orbit-dependent pairing problem is derived by introducing an infinite-dimensional algebra. A method for obtaining eigenvalues and eigenvectors of the corresponding Hamiltonian is also…

Nuclear Theory · Physics 2009-10-30 Feng Pan , J. P. Draayer , W. E. Ormand

Newton-Raphson method in complex space is used to numerically solve the transcendental dispersion relation of low frequency shear Alfven waves in fusion plasmas. The equation exhibits several physically relevant basins of attraction. The…

Plasma Physics · Physics 2021-11-09 Ilija Chavdarovski

Coherent Deeply virtual Compton scattering off the $^4$He nucleus is studied in impulse approximation. A convolution formula for the nuclear Generalized Parton Distribution (GPD) is derived in terms of the $^4$He non-diagonal spectral…

Nuclear Theory · Physics 2018-07-18 Sara Fucini , Sergio Scopetta , Michele Viviani

Fission fragments' charge and mass distribution is an important input to applications ranging from basic science to energy production or nuclear non-proliferation. In simulations of nucleosynthesis or calculations of superheavy elements,…

Nuclear Theory · Physics 2021-05-12 Marc Verriere , David Regnier , Nicolas Schunck

Immersion optics enable creation of systems with improved optical concentration and coupling by taking advantage of the fact that the luminance of light is proportional to the square of the refractive index in a lossless optical system.…

Optics · Physics 2022-11-22 Nina Vaidya , Olav Solgaard

We solve the integral equation describing the propagation of light in an isothermal plane-parallel atmosphere of optical thickness $\tau^*$, adopting a uniform thermalization parameter $\epsilon$. The solution given by the ALI method,…

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

In this paper we investigate the numerical approximation of the fractional diffusion, advection, reaction equation on a bounded interval. Recently the explicit form of the solution to this equation was obtained. Using the explicit form of…

Numerical Analysis · Mathematics 2020-02-07 Xiangcheng Zheng , V. J. Ervin , Hong Wang

In the context of ultra-relativistic nuclear collisions, we present a fast method for calculating the final particle spectra after the direct decay of resonances from a Cooper-Frye integral over the freeze-out surface. The method is based…

Nuclear Theory · Physics 2019-04-30 Aleksas Mazeliauskas , Stefan Floerchinger , Eduardo Grossi , Derek Teaney

It is well known that using high-order numerical algorithms to solve fractional differential equations leads to almost the same computational cost with low-order ones but the accuracy (or convergence order) is greatly improved, due to the…

Numerical Analysis · Mathematics 2017-05-25 Hengfei Ding , Changpin Li

We introduce a general framework for solving partial differential equations (PDEs) using generative diffusion models. In particular, we focus on the scenarios where we do not have the full knowledge of the scene necessary to apply classical…

Machine Learning · Computer Science 2024-11-04 Jiahe Huang , Guandao Yang , Zichen Wang , Jeong Joon Park

The probability distribution of lens image separations is calculated for the ``standard'' gravitational lensing statistics model in an arbitrary, flat Robertson-Walker universe, where lensing galaxies are singular isothermal spheres that…

Astrophysics · Physics 2008-11-26 Myeong-Gu Park

A brief overview of various approaches to the optical-model description of nuclei is presented. A survey of some of the formal aspects is given which links the Feshbach formulation for either the hole or particle Green's function to the…

Nuclear Theory · Physics 2019-03-27 Willem H. Dickhoff , Robert J. Charity