Now showing items 1-10 of 831
Perturbations and chaos in quantum maps
(American Physical Society, 2012-08)
The local density of states (LDOS) is a distribution that characterizes the effects of perturbations on quantum systems. Recently, a semiclassical theory was proposed for the LDOS of chaotic billiards and maps. This theory ...
On the straightforward perturbation theory in classical mechanics
(IOP Publishing, 2018-06)
We show that it is possible to extract useful information from the straightforward perturbation theory in classical mechanics. Although the secular terms make the perturbation series useless for large times, these expansions ...
The kondo problem for very dilute ZnMn alloys under a Doorway State perturbation approach
(Facultad Experimental de Ciencias de la Universidad del Zulia, 2011)
The effect of finite rank perturbations on Jordan chains of linear operators
(Elsevier Science Inc, 2015-08-15)
A general result on the structure and dimension of the root subspaces of a linear operator under finite rank perturbations is proved: The increase of dimension from the n-th power of the kernel of the perturbed operator ...
Perturbations of the Haar wavelet by convolution
(American Mathematical Society, 2001-10)
In this note we show that the standard convolution regularization of the Haar system generates Riesz bases of smooth functions for L2(R), providing in this way an alternative to the approach given by Govil and Zalik [Proc. ...
Perturbed frame sequences: Canonical dual systems, approximate reconstructions and applications
(World Scientific, 2014-03)
We consider perturbation of frames and frame sequences in a Hilbert space. It is known that small perturbations of a frame give rise to another frame. We show that the canonical dual of the perturbed sequence is a perturbation ...
Point mass perturbations of spectral measures
(Rocky Mountain Mathematics Consortium, 2021-08-05)
Using a generalization of the moment problem and the extremal properties of spectral measures corresponding to the self-adjoint extensions of a regular symmetric operator, we study point mass perturbations of spectral ...
Comment on 'Analytical approach for solving population balances: A homotopy perturbation method' (2019) J. Phys. A: Math. Theor. 52385201
(IOP Publishing, 2020-09)
We analyse a recent application of homotopy perturbation method to some models for population balances. We show that the only result of the application of this implementation of the perturbation approach is the Taylor ...
Finite rank perturbations of linear relations and matrix pencils
(Birkhauser Verlag Ag, 2021-02)
We elaborate on the deviation of the Jordan structures of two linear relations that are finite-dimensional perturbations of each other. We compare their number of Jordan chains of length at least n. In the operator case, ...
Assessing mammal responses to perturbations in temperate aridlands of Argentina
(Academic Press Ltd - Elsevier Science Ltd, 2003-12)
Loss of species richness and reduced abundance have been the main responses to perturbations of small- and medium-sized mammals in arid and semi-arid areas. Nonetheless, some mammal species whose habitat requirements are ...