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Data from a network of gravitational wave detectors can be analyzed in coincidence to increase detection confidence and reduce non-stationarity of the background. We propose and explore a geometric algorithm to combine the data from a…

General Relativity and Quantum Cosmology · Physics 2009-02-20 C. A. K. Robinson , B. S. Sathyaprakash , Anand S. Sengupta

The spherical grasshopper problem is a geometric optimization problem that arises in the context of Bell inequalities and can be interpreted as identifying the best local hidden variable approximation to quantum singlet correlations for…

Quantum Physics · Physics 2026-05-07 David Llamas , Dmitry Chistikov , Adrian Kent , Mike Paterson , Olga Goulko

The scattering of scalar waves by a set of scatterers is considered. It is proven that the scattered field can be represented as an integral supported by any smooth surface enclosing the scatterers. This is a generalization of the series…

Mathematical Physics · Physics 2024-10-22 Didier Felbacq , Anthony Gourdin , Emmanuel Rousseau

We summarize recent results initiating spectral analysis on pseudo-Riemannian locally symmetric spaces $\Gamma \backslash G/H$, beyond the classical setting where $H$ is compact (e.g. theory of automorphic forms for arithmetic $\Gamma$) or…

Spectral Theory · Mathematics 2021-06-16 Fanny Kassel , Toshiyuki Kobayashi

In this talk I review recent progresses in the detection of scalar gravitational waves. Furthermore, in the framework of the Jordan-Brans-Dicke theory, I compute the signal to noise ratio for a resonant mass detector of spherical shape and…

General Relativity and Quantum Cosmology · Physics 2007-05-23 F. Fucito

The solution in sense of Prager&Synge is the alternative to the commonly used notion of the numerical solution, which is considered as a limit of grid functions at mesh refinement. Prager&Synge solution is defined as a hypersphere…

Numerical Analysis · Mathematics 2024-03-12 A. K. Alekseev , A. E. Bondarev

A new grid system on a sphere is proposed that allows for straight-forward implementation of both spherical-harmonics-based spectral methods and gridpoint-based multigrid methods. The latitudinal gridpoints in the new grid are equidistant…

Atmospheric and Oceanic Physics · Physics 2019-10-22 Daisuke Hotta , Masashi Ujiie

A floating hemisphere under forced harmonic oscillation at very high and very low frequencies is considered. The problem is reduced to an elliptic one, that is, the Laplace operator in the exterior domain with standard Dirichlet and Neumann…

Numerical Analysis · Mathematics 2025-10-20 M. A. Storti , J. D'Elia

We present a numerical method for solving the free-space Maxwell's equations in three dimensions using compact convolution kernels on a rectangular grid. We first rewrite Maxwell's Equations as a system of wave equations with auxiliary…

Numerical Analysis · Mathematics 2019-07-24 Boris Lo , Phillip Colella

In frequency domain analysis for spatial data, spectral averages based on the periodogram often play an important role in understanding spatial covariance structure, but also have complicated sampling distributions due to complex variances…

Statistics Theory · Mathematics 2025-04-29 Souvick Bera , Daniel J. Nordman , Soutir Bandyopadhyay

In many applications data are measured or defined on a spherical manifold; spherical harmonic transforms are then required to access the frequency content of the data. We derive algorithms to perform forward and inverse spin spherical…

Astrophysics · Physics 2011-10-28 J. D. McEwen

To solve the spinor-spinor Bethe-Salpeter equation in Euclidean space we propose a novel method related to the use of hyperspherical harmonics. We suggest an appropriate extension to form a new basis of spin-angular harmonics that is…

Nuclear Theory · Physics 2008-12-25 S. M. Dorkin , M. Beyer , S. S. Semikh , L. P. Kaptari

We investigate numerical methods for wave equations in $n+2$ spacetime dimensions, written in spherical coordinates, decomposed in spherical harmonics on $S^n$, and finite-differenced in the remaining coordinates $r$ and $t$. Such an…

Numerical Analysis · Mathematics 2024-07-11 Carsten Gundlach , Jose M. Martin-Garcia , David Garfinkle

In this paper we present a hybrid approach to numerically solve two-dimensional electromagnetic inverse scattering problems, whereby the unknown scatterer is hosted by a possibly inhomogeneous background. The approach is `hybrid' in that it…

Analysis of PDEs · Mathematics 2012-10-22 G. Giorgi , M. Brignone , R. Aramini , M. Piana

Spherical harmonics provide a smooth, orthogonal, and symmetry-adapted basis to expand functions on a sphere, and they are used routinely in physical and theoretical chemistry as well as in different fields of science and technology, from…

Chemical Physics · Physics 2023-05-02 Filippo Bigi , Guillaume Fraux , Nicholas J. Browning , Michele Ceriotti

This paper discusses sparse isotropic regularization for a random field on the unit sphere $\mathbb{S}^2$ in $\mathbb{R}^{3}$, where the field is expanded in terms of a spherical harmonic basis. A key feature is that the norm used in the…

Numerical Analysis · Mathematics 2018-01-11 Quoc T. Le Gia , Ian H. Sloan , Robert S. Womersley , Yu Guang Wang

Spatial frequency estimation from a mixture of noisy sinusoids finds applications in various fields. While subspace-based methods offer cost-effective super-resolution parameter estimation, they demand precise array calibration, posing…

Signal Processing · Electrical Eng. & Systems 2024-10-23 Tianyi Liu , Sai Pavan Deram , Khaled Ardah , Martin Haardt , Marc E. Pfetsch , Marius Pesavento

Graph-structured data is ubiquitous in scientific domains, where models often face imbalanced learning settings. In imbalanced regression, domain preferences focus on specific target value ranges that represent the most scientifically…

Machine Learning · Computer Science 2025-07-15 Brenda Nogueira , Gabe Gomes , Meng Jiang , Nitesh V. Chawla , Nuno Moniz

This letter considers the problem of recovering a positive stream of Diracs on a sphere from its projection onto the space of low-degree spherical harmonics, namely, from its low-resolution version. We suggest recovering the Diracs via a…

Information Theory · Computer Science 2015-10-28 Tamir Bendory , Yonina C. Eldar

We present a new formulation of the multipolar expansion of an exact boundary condition for the wave equation, which is truncated at the quadrupolar order. Using an auxiliary function, that is the solution of a wave equation on the sphere…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Jerome Novak , Silvano Bonazzola