arXiv subjects

R. A. Méndez-Sánchez

Publications and source records attributed to R. A. Méndez-Sánchez.

23 records · Page 2Linked to original sources

arXiv2011

Absorption and Direct Processes in Chaotic Wave Scattering

Recent results on the scattering of waves by chaotic systems with losses and direct processes are discussed. We start by showing the results without direct processes nor absorption. We then discuss systems with direct processes and lossy systems separately. Finally the discussion of systems with both direct processes and loses is given. We will see how the regimes of strong and weak absorption are modified by the presence of the direct processes.

cond-mat.mes-hall↗

arXiv2010

Building and Destroying Symmetry in 1-D Elastic Systems

Locally periodic rods, which show approximate invariance with respect to translations, are constructed by joining $N$ unit cells. The spectrum then shows a band spectrum. We then break the local periodicity by including one or more defects in the system. When the defects follow a certain definite prescription, an analog of the Wannier-Stark ladders is gotten; when the defects are random, an elastic rod showing Anderson localization is obtained. In all cases experimental values match the theoretical predictions.

cond-mat.dis-nn↗

arXiv2010

Doorway States and Billiards

Whenever a distinct state is immersed in a sea of complicated and dense states, the strength of the distinct state, which we refer to as a doorway, is distributed in their neighboring states. We analyze this mechanism for 2-D billiards with different geometries. One of them is symmetric and integrable, another is symmetric but chaotic, and the third has a capricious form. The fact that the doorway-state mechanism is valid for such highly diverse cases, proves that it is robust.

nlin.CD↗

arXiv2006

Nearest neighbour spacing distribution of basis in some intron-less and intron-containing DNA sequences

We show that the nearest neighbour distribution of distances between basis pairs of some intron-less and intron-containing coding regions are the same when a procedure, called {\em unfolding}, is applied. Such a procedure consists in separating the secular variations from the oscillatory terms. The form of the distribution obtained is quite similar to that of a random, i.e. Poissonian, sequence. This is done for the HUMBMYH7CD, DROMYONMA, HUMBMYH7 and DROMHC sequences. The first two correspond to highly coding regions while the last two correspond to non-coding regions. We also show that the distributions before the unfolding procedure depend on the secular part but, after the unfolding procedure we obtain an striking result: all distributions are similar to each other. The result becomes independent of the content of introns or the species we have chosen. This is in contradiction with the results obtained with the detrended fluctuation analysis in which the correlations yield different results for intron-less and intron-containing regions.

q-bio.QM↗

arXiv2003

Topological defects in 1D elastic waves

It has been recently shown theoretically that a topological defect in a 1D periodic potential may give rise to two localized states within the energy gaps. In this work we present an experimental realization of this effect for the case of torsional waves in elastic rods. We also show numerically that three, or even more, localized states can be present if the parameters characterizing the topological defect are suitably varied.

cond-mat.dis-nn↗