For the eigenvalue function on symmetric matrices, we have gathered a number of it’s properties.We show that this map has the properties of continuity, strict continuity, directional differentiability, Frechet differentiability, continuous  differentiability. Eigenvalue function will be extended to a larger set of matrices and then the listed properties will prove again.

In [6], it was shown that if U is a random n×n unitary matrix, then for any p ≥ n, the eigenvalues of Up are i.i.d. uniform; similar results were also shown for general compact Lie groups. We study what happens when p < n instead. For the classical groups, we find that we can describe the eigenvalue distribution of Up in terms of the eigenvalue distributions of smaller classical groups; the ear...

An efficient semi-analytic method is developed for computing the band structures of two-dimensional photonic crystals which are triangular lattices of circular cylinders. The problem is formulated as an eigenvalue problem for a given frequency using the Dirichlet-to-Neumann (DtN) map of a hexagon unit cell. This is a linear eigenvalue problem even if the material is dispersive, where the eigenv...

Perturbation methods are used to solve the eigenvalue problem for cortical pattern formation in the presence of long-range neural connections. Such connections have a crystallinelike structure that breaks Euclidean symmetry to the discrete symmetry of a planar lattice group. Conditions for marginal stability are derived with the associated eigenmodes identified as Bloch waves.

The critical behavior for intermittency is studied in two coupled one-dimensional (1D) maps. We find two fixed maps of an approximate renormalization operator in the space of coupled maps. Each fixed map has a common relavant eigenvalue associated with the scaling of the control parameter of the uncoupled one-dimensional map. However, the relevant “coupling eigenvalue” associated with coupling ...

We examine the adjacency matrices of three-regular graphs representing one-face maps. Numerical studies reveal that the limiting eigenvalue statistics of these matrices are the same as those of much larger, and more widely studied classes from Random Matrix Theory. We present an algorithm for generating matrices corresponding to maps of genus zero, and find the eigenvalue statistics in the genu...

For a square matrix A, let S(A) be an eigenvalue inclusion set such as the Gershgorin region, the union of Cassini ovals, and the Ostrowski’s set. Characterization is obtained for maps Φ on n×n matrices satisfying S(Φ(A)Φ(B)) = S(AB) for all matrices A and B.

A renormalization scheme is introduced to study quantum Anosov maps (QAMs) on a torus for general boundary conditions (BCs), whose number ( k) is always finite. It is shown that the quasienergy eigenvalue problem of a QAM for all k BCs is exactly equivalent to that of the renormalized QAM (with Planck's constant Planck's over 2pi(') = Planck's over 2pi/k) at some fixed BCs that can be of four t...

We propose a criterion for the destruction of a two-dimensional torus through the formation of an infinite set of cusp points on the closed invariant curves defining the resonance torus. This mechanism is specific to noninvertible maps. The cusp points arise when the tangent to the torus at the point of intersection with the critical curve L(0) coincides with the eigendirection corresponding to...

For photonic crystals (PhCs) and related devices, it is useful to calculate the Dirichlet-to-Neumann (DtN) map of a unit cell, which maps the wave field to its normal derivative on the boundary. The DtN map can be used to avoid further calculations in the interiors of the unit cells and formulate mathematical problems on the cell boundaries. We develop a method to approximate the DtN map for tw...