Results 21 to 30 of about 74 (72)
Double Copy From Tensor Products of Metric BV■‐Algebras
Fortschritte der Physik, Volume 73, Issue 1-2, February 2025.Abstract Field theories with kinematic Lie algebras, such as field theories featuring color–kinematics duality, possess an underlying algebraic structure known as BV■‐algebra. If, additionally, matter fields are present, this structure is supplemented by a module for the BV■‐algebra.
Leron Borsten +5 more
wiley +1 more source
Mathematical Methods in the Applied Sciences, Volume 48, Issue 2, Page 2267-2293, 30 January 2025.We study the Helmholtz equation with periodic coefficients in a closed waveguide. A functional analytic approach is used to formulate and solve the radiation problem in a self‐contained exposition. In this context, we simplify the non‐degeneracy assumption on the frequency.
A. Kirsch, B. Schweizer
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Journal of the London Mathematical Society, Volume 110, Issue 5, November 2024.Abstract The aim of this paper is to prove the existence of Hadamard states for the Maxwell equations on any globally hyperbolic spacetime. This will be achieved by introducing a new gauge fixing condition, the Cauchy radiation gauge, that will allow to suppress all the unphysical degrees of freedom. The key ingredient for achieving this gauge is a new
Simone Murro, Gabriel Schmid
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Spectral problems and orthogonal polynomials on the unit circle [PDF]
, 2012 The main purpose of the work presented here is to study transformations of sequences of orthogonal polynomials associated with a hermitian linear functional L, using spectral transformations of the corresponding C-function F.
Castillo Rodríguez, Kenier
core
Accelerating Nonequilibrium Green Functions Simulations: The G1–G2 Scheme and Beyond
physica status solidi (b), Volume 261, Issue 9, September 2024.This article reviews recent developments in the theory of nonequilibrium Green functions (NEGF) where dramatic accelerations are achieved within the time‐local G1–G2 scheme. As a result, longer simulations with more accurate selfenergies are possible. The figure shows an illustration ‐ optical excitation of graphene by a short laser pulse: snapshot of ...
Michael Bonitz +5 more
wiley +1 more source
Local Whittle estimation with (quasi‐)analytic wavelets
Journal of Time Series Analysis, Volume 45, Issue 3, Page 421-443, May 2024.In the general setting of long‐memory multivariate time series, the long‐memory characteristics are defined by two components. The long‐memory parameters describe the autocorrelation of each time series. And the long‐run covariance measures the coupling between time series, with general phase parameters.
Sophie Achard, Irène Gannaz
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Octonionic Magical Supergravity, Niemeier Lattices, and Exceptional & Hilbert Modular Forms
Fortschritte der Physik, Volume 72, Issue 2, February 2024.Abstract The quantum degeneracies of Bogomolny‐Prasad‐Sommerfield (BPS) black holes of octonionic magical supergravity in five dimensions are studied. Quantum degeneracy is defined purely number theoretically as the number of distinct states in charge space with a given set of invariant labels.
Murat Günaydin, Abhiram Kidambi
wiley +1 more source
Detecting hyperbolic and definite matrix polynomials
, 2009 Hyperbolic or more generally definite matrix polynomials are important classes of Hermitian matrix polynomials. They allow for a definite linearization and can therefore be solved by a standard algorithm for Hermitian matrices.
Voß, Heinrich, Niendorf, Vasco
core
Developing HSS iteration schemes for solving the quadratic matrix equation AX2+BX+C=0$AX^{2}+BX+C=0$
IET Control Theory &Applications, Volume 18, Issue 3, Page 335-349, February 2024.The quadratic matrix equation (QME) Q(X)=AX2+BX+C,$$\begin{equation*} Q(X)=AX^{2}+BX+C, \end{equation*}$$occurs in the branches such as the quadratic eigenvalue problems and quasi‐birth‐death processes. Also, the numerical solution of QMEs is an essential step in many computational methods for linear‐ quadratic and robust control, filtering, controller
Raziyeh Erfanifar, Masoud Hajarian
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Numerical Linear Algebra with Applications, Volume 31, Issue 1, January 2024.Abstract We consider here a cell‐centered finite difference approximation of the Richards equation in three dimensions, averaging for interface values the hydraulic conductivity K=K(p)$$ K=K(p) $$, a highly nonlinear function, by arithmetic, upstream and harmonic means.
Daniele Bertaccini +3 more
wiley +1 more source