Results 31 to 40 of about 2,942 (77)
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
wiley +1 more source
The cryptohermitian smeared-coordinate representation of wave functions
, 2011 The one-dimensional real line of coordinates is replaced, for simplification or approximation purposes, by an N-plet of the so called Gauss-Hermite grid points. These grid points are interpreted as the eigenvalues of a tridiagonal matrix $\mathfrak{q}_0$
Abramowitz +22 more
core +1 more source
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
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
wiley +1 more source
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
Numerical Linear Algebra with Applications, Volume 31, Issue 1, January 2024.Summary An important class of nonlinear weighted least‐squares problems arises from the assimilation of observations in atmospheric and ocean models. In variational data assimilation, inverse error covariance matrices define the weighting matrices of the least‐squares problem.
Olivier Goux +4 more
wiley +1 more source
Polaritonic response theory for exact and approximate wave functions
WIREs Computational Molecular Science, Volume 14, Issue 1, January/February 2024.The theory behind polaritonic chemistry is discussed from a single‐molecule chemical perspective. We derive a response framework for quantum electrodynamics and provide approximate response equations for ab initio QED‐HF and QED‐CC. Abstract Polaritonic chemistry is an interdisciplinary emerging field that presents several challenges and opportunities ...
Matteo Castagnola +4 more
wiley +1 more source
Iterative Deterministic Equivalents for the Performance Analysis of Communication Systems [PDF]
, 2011 In this article, we introduce iterative deterministic equivalents as a novel technique for the performance analysis of communication systems whose channels are modeled by complex combinations of independent random matrices.
Couillet, Romain +2 more
core
Relative entropy and the multi-variable multi-dimensional moment problem
, 2005 Entropy-like functionals on operator algebras have been studied since the pioneering work of von Neumann, Umegaki, Lindblad, and Lieb. The most well-known are the von Neumann entropy $trace (\rho\log \rho)$ and a generalization of the Kullback-Leibler ...
Georgiou, Tryphon T.
core
Rényi Entropy, Signed Probabilities, and the Qubit. [PDF]
Entropy (Basel), 2022 Brandenburger A, La Mura P, Zoble S.
europepmc +1 more source