Results 11 to 20 of about 169 (35)

Generalized Finite Algorithms for Constructing Hermitian Matrices with Prescribed Diagonal and Spectrum [PDF]

open access: yes, 2005
In this paper, we present new algorithms that can replace the diagonal entries of a Hermitian matrix by any set of diagonal entries that majorize the original set without altering the eigenvalues of the matrix.
Dhillon, Inderjit S.   +3 more
core   +2 more sources

ESTIMATION OF THE MAXIMUM MULTIPLICITY OF AN EIGENVALUE IN TERMS OF THE VERTEX DEGREES OF THE GRAPH [PDF]

open access: yes, 2002
. The maximum multiplicity among eigenvaluesof matriceswith a given graph cannot generally be expressed in terms of the degrees of the vertices (even when the graph is a tree).
Carlos   +3 more
core   +2 more sources

Dimension of the intersection of a pair of orthogonal groups [PDF]

open access: yes, 2009
Let $g,h\colon V\times V\rightarrow mathbb{C}$ be two non-degenerate symmetric bilinear forms on a finite-dimensional complex vector space $V$. Let $G$ (resp.\ $H$) be the Lie group of isometries of $g$ (resp.\ $h$).
Song, Seok-Zun   +4 more
core   +1 more source

Asymptotic spectral properties of totally symmetric multilevel Toeplitz matrices [PDF]

open access: yes, 2002
Let n=(n1,…,nk) be a multiindex and κ(n̲)=∏j=1knj. We say that n→∞ if ni→∞, 1⩽i⩽k. If r=(r1,…,rk) and s=(s1,…,sk), let ∣r−s∣=(∣r1−s1∣,…,∣s1−sk∣). We say that a multilevel Toeplitz matrix of the form Tn̲=[t|r̲-s̲|]r̲,s̲=1̲∞̲ is totally symmetric.
Gri Espinagosa, Josep   +1 more
core   +1 more source

μ-values and spectral value sets for linear perturbation classes defined by a scalar product [PDF]

open access: yes, 2011
We study the variation of the spectrum of matrices under perturbations which are self- or skew-adjoint with respect to a scalar product. Computable formulas are given for the associated μ-values.
Karow, Michael
core   +1 more source

Critical points of the optimal quantum control landscape: a propagator approach

open access: yes, 2012
Numerical and experimental realizations of quantum control are closely connected to the properties of the mapping from the control to the unitary propagator.
Ho, Tak-San   +2 more
core   +3 more sources

Minimal hermitian matrices with fixed entries outside the diagonal [PDF]

open access: yes, 2008
We survey some results concerning the problem of finding the complex hermitian matrix or matrices of least supremum norm with variable diagonal. Some qualitative general results are given and more specific descriptions are shown for the 3 x 3 case.
Andruchow, Esteban   +4 more
core  

Classification of pairs of rotations in finite-dimensional Euclidean space

open access: yes, 2008
A rotation in a Euclidean space V is an orthogonal map on V which acts locally as a plane rotation with some fixed angle. We give a classification of all pairs of rotations in finite-dimensional Euclidean space, up to simultaneous conjugation with ...
Darpö, Erik
core   +2 more sources

On universality of local edge regime for the deformed Gaussian Unitary Ensemble

open access: yes, 2013
We consider the deformed Gaussian ensemble $H_n=H_n^{(0)}+M_n$ in which $H_n^{(0)}$ is a hermitian matrix (possibly random) and $M_n$ is the Gaussian unitary random matrix (GUE) independent of $H_n^{(0)}$. Assuming that the Normalized Counting Measure of
A. Lytova   +23 more
core   +1 more source

Bounds on changes in Ritz values for a perturbed invariant subspace of a Hermitian matrix

open access: yes, 2008
The Rayleigh-Ritz method is widely used for eigenvalue approximation. Given a matrix $X$ with columns that form an orthonormal basis for a subspace $\X$, and a Hermitian matrix $A$, the eigenvalues of $X^HAX$ are called Ritz values of $A$ with respect to
A. V. Knyazev   +4 more
core   +1 more source

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