Results 41 to 50 of about 3,570,033 (364)

Unitary equivalence to a complex symmetric matrix: a modulus criterion [PDF]

open access: yes, 2010
We develop a procedure for determining whether a square complex matrix is unitarily equivalent to a complex symmetric (i.e., self-transpose) matrix. Our approach has several advantages over existing methods.
S. Garcia, Daniel E. Poore, M. Wyse
semanticscholar   +1 more source

Symmetric multisplitting of a symmetric positive definite matrix

open access: yesLinear Algebra and its Applications, 1998
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Zhi-Hao Cao, Zhong-Yun Liu
openaire   +2 more sources

PT Symmetry as a Generalization of Hermiticity

open access: yes, 2010
The Hilbert space in PT-symmetric quantum mechanics is formulated as a linear vector space with a dynamic inner product. The most general PT-symmetric matrix Hamiltonians are constructed for 2*2 and 3*3 cases.
Ballentine L E   +9 more
core   +1 more source

Cauchy's interlace theorem and lower bounds for the spectral radius

open access: yesInternational Journal of Mathematics and Mathematical Sciences, 2000
We present a short and simple proof of the well-known Cauchy interlace theorem. We use the theorem to improve some lower bound estimates for the spectral radius of a real symmetric matrix.
A. McD. Mercer, Peter R. Mercer
doaj   +1 more source

Smoothed analysis of symmetric random matrices with continuous distributions [PDF]

open access: yes, 2015
We study invertibility of matrices of the form $D+R$ where $D$ is an arbitrary symmetric deterministic matrix, and $R$ is a symmetric random matrix whose independent entries have continuous distributions with bounded densities. We show that $|(D+R)^{-1}|
Farrell, Brendan, Vershynin, Roman
core   +3 more sources

The derivative of an orthogonal matrix of eigenvectors of a symmetric matrix

open access: yesLinear Algebra and its Applications, 1997
Let \(M\) be a real symmetric \(p\times p\) matrix with distinct eigenvalues \(\lambda_i\) and associated normalized eigenvectors \(w_i\), \(1\leq i\leq p\). There are real-valued functions \(\psi_i\) and vector-valued functions \(f_i\) defined for all matrices \(Z\) in some neighborhood \({\mathcal N} (M) \subseteq \mathbb{R}^{p \times p}\) of \(M ...
Kollo, T., Neudecker, H.
openaire   +5 more sources

Symmetrical parametrizations of the lepton mixing matrix [PDF]

open access: yesPhysical Review D, 2011
Advantages of the original symmetrical form of the parametrization of the lepton mixing matrix are discussed. It provides a conceptually more transparent description of neutrino oscillations and lepton number violating processes like neutrinoless double beta decay, clarifying the significance of Dirac and Majorana phases.
Rodejohann, Werner   +1 more
openaire   +5 more sources

PT-Symmetric, Quasi-Exactly Solvable matrix Hamiltonians [PDF]

open access: yes, 2007
Matrix quasi exactly solvable operators are considered and new conditions are determined to test whether a matrix differential operator possesses one or several finite dimensional invariant vector spaces.
Ancilla Nininahazwe   +8 more
core   +2 more sources

Unitary equivalence to a complex symmetric matrix: geometric criteria [PDF]

open access: yes, 2009
We develop several methods, based on the geometric relationship between the eigenspaces of a matrix and its adjoint, for determining whether a square matrix having distinct eigenvalues is unitarily equivalent to a complex symmetric matrix.
S. Garcia, L. Balayan
semanticscholar   +1 more source

Symmetric matrix pencils

open access: yesJournal of Computational and Applied Mathematics, 1991
Typical matrix eigenvalue problems, quadratic or linear, are best formulated as pencils \((A,M)\) in which both \(A\) and \(M\) are real and symmetric. This fact is emphasized in the paper through a set of physical examples. Then, the canonical forms are used to explain the role of the sign characteristic attached to real eigenvalues.
openaire   +3 more sources

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