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A new method is presented for Fourier decomposition of the Helmholtz Green Function in cylindrical coordinates, which is equivalent to obtaining the solution of the Helmholtz equation for a general ring source. The Fourier coefficients of…

Mathematical Physics · Physics 2015-05-14 John T. Conway , Howard S. Cohl

We introduce a practical and efficient approach for calculating the all-electron full potential bandstructure in real space, employing a finite element basis. As an alternative to the k-space method, the method involves the self-consistent…

Materials Science · Physics 2023-07-25 Dongming Li , James Kestyn , Eric Polizzi

We present a treatise on solving the Takagi-Taupin equations in the case of a strain field with an additional, spatially slowly varying component (owing to \emph{e.g.}~heat expansion or angular compression). We show that the presence of…

Optics · Physics 2016-06-03 Ari-Pekka Honkanen , Giulio Monaco , Simo Huotari

We present a new variational model for computing the electronic first-order density matrix of a crystalline material in presence of a local defect. A natural way to obtain variational discretizations of this model is to expand the…

Other Condensed Matter · Physics 2009-11-13 Eric Cances , Amelie Deleurence , Mathieu Lewin

We deal with the problem of reconstructing material coefficients from the farfields they generate. By embedding small (single) inclusions to these media, located at points $z$ in the support of these materials, and measuring the farfields…

Analysis of PDEs · Mathematics 2016-10-20 Ahmed Alsaedi , Faris Alzahrani , Durga Prasad Challa , Mokhtar Kirane , Mourad Sini

We develop a mathematical and numerical framework for studying evanescent waves in subwavelength band gap materials. By establishing a link between the complex Brillouin zone and various Hermitian and non-Hermitian phenomena, including…

Analysis of PDEs · Mathematics 2025-02-11 Yannick De Bruijn , Erik Orvehed Hiltunen

Beamforming methods for sound source localization are usually based on free-field Green's functions to model the sound propagation between source and microphone. This assumption is known to be incorrect for many industrial applications and…

Audio and Speech Processing · Electrical Eng. & Systems 2020-11-02 Marius Lehmann , Daniel Ernst , Marc Schneider , Carsten Spehr , Markus Lummer

A new method of solution is proposed for solution of the wave equation in one space dimension with continuously-varying coefficients. By considering all paths along which information arrives at a given point, the solution is expressed as an…

Analysis of PDEs · Mathematics 2019-10-11 Jithin D. George , David I. Ketcheson , Randall J. LeVeque

Storage systems have a strong need for substantially improving their error correction capabilities, especially for long-term storage where the accumulating errors can exceed the decoding threshold of error-correcting codes (ECCs). In this…

Information Theory · Computer Science 2018-11-12 Pulakesh Upadhyaya , Anxiao , Jiang

Photonic crystals (PhCs) are periodic dielectric structures that exhibit unique electromagnetic properties, such as the creation of band gaps where electromagnetic wave propagation is inhibited. Accurately predicting dispersion relations,…

Numerical Analysis · Mathematics 2024-11-12 Yueqi Wang , Richard Craster , Guanglian Li

A new method to improve the accuracy and efficiency of characteristic mode (CM) decomposition for perfectly conducting bodies is presented. The method uses the expansion of the Green dyadic in spherical vector waves. This expansion is…

Computational Physics · Physics 2019-04-05 Doruk Tayli , Miloslav Capek , Lamyae Akrou , Vit Losenicky , Lukas Jelinek , Mats Gustafsson

It is argued that electron density dynamic's response to phonons at the Brillouin zone boundary is the key factor in the superconductivity mechanism of MgB2 as well as of all superconducting compounds leading to a real space electron-hole…

Superconductivity · Physics 2020-05-15 T. Guerfi

Near the band edge of photonic crystal waveguides, localized modes appear due to disorder. We demonstrate a new method to elucidate spatial profile of the localized modes in such systems using precise local tuning. Using deconvolution with…

Optics · Physics 2016-11-03 J. Lian , S. Sokolov , E. Yüce , S. Combrié , A. De Rossi , A. P. Mosk , .

Thermal properties are of great interest in modern electronic devices and nanostructures. Calculating these properties is straightforward when the device is made from a pure material, but problems arise when alloys are used. Specifically,…

Mesoscale and Nanoscale Physics · Physics 2015-06-22 Timothy B. Boykin , Arvind Ajoy , Hesameddin Ilatikhameneh , Michael Povolotskyi , Gerhard Klimeck

This paper considers the approximation of spatial convolution with a given radial integral kernel. Previous studies have demonstrated that approximating spatial convolution using a system of partial differential equations (PDEs) can…

Analysis of PDEs · Mathematics 2025-04-15 Hiroshi Ishii , Yoshitaro Tanaka

We present a Green's function formulation of the quantum defect embedding theory (QDET) where a double counting scheme is rigorously derived within the $G_0 W_0$ approximation. We then show the robustness of our methodology by applying the…

Quantum Physics · Physics 2022-06-07 Nan Sheng , Christian Vorwerk , Marco Govoni , Giulia Galli

The complex scaling method (CSM) is a useful similarity transformation of the Schr\"odinger equation, in which bound-state spectra are not changed but continuum spectra are separated into resonant and non-resonant continuum ones. Because…

Nuclear Theory · Physics 2014-10-17 Takayuki Myo , Yuma Kikuchi , Hiroshi Masui , Kiyoshi Kato

Numerical calculation of modes in dispersive and absorptive systems is performed using the finite element method. The dispersion is tackled in the frame of an extension of Maxwell's equations where auxiliary fields are added to the…

Optics · Physics 2016-04-20 Yoann Brûlé , Guillaume Demésy , Boris Gralak

A boundary element method based on a Green's function technique is introduced to compute resonances with intermediate lifetimes in quasi-two-dimensional dielectric cavities. It can be applied to single or several optical resonators of…

Optics · Physics 2009-11-07 Jan Wiersig

A new method for calculation of band structure has been proposed based on the Green's function theory and local sampling. Potential energy in the Hamiltonian of Schrodinger's equation is approximated with a series of sampled Dirac delta…

Mesoscale and Nanoscale Physics · Physics 2010-02-24 Milad Khoshnegar , Sina Khorasani , Amirhossein Hosseinnia