Search results for "wave"

Highly Sensitive Polarization Rotation Measurement through a High‐Order Vector Beam Generated by a Metasurface

2020

The precise determination of the polarization state of light is fundamental for a vast variety of applications in remote sensing, astronomy, optics and terahertz technology, to name just a few. Typically, polarization characterization is performed by using a combination of multiple optical devices such as beam splitters, polarizers, and waveplates. Moreover, to achieve high-precision, balanced photodetectors and lock-in amplifiers are employed, thus contributing to increasing system complexity. Here, a technique for polarization rotation measurements with a dynamic range of 180° and a sensitivity of about 10−2 degrees is realized using a properly designed metasurface. Such device generates …

Few-body insights of multiquark exotic hadrons

2018

In this contribution we discuss the adequate treatment of the $4-$ and $5-$body dynamics within a constituent quark framework. We stress that the variational and Born-Oppenheimer approximations give energies rather close to the exact ones, while the diquark approximation might be rather misleading. Hall-Post inequalities provide very useful lower bounds that exclude possible stable states for some mass ratios and color wave functions.

Evaluation of the wave energy density on the Sicilian coast

2016

In this article the wave energy density of the northern Sicilian coasts is evaluated and is used to evaluate the producibility of a wave nergy converter to be installed in an area in the north west part of Sicily. In particular, the objective of the study is the evaluation of a potential installation in an area between Trapani and Palermo, which are the largest cities in the north west part of Sicily. In particular in this research, the wave energy density of Sicily has been analyzed by using an analysis of wave data carried out in a 10-year period, using the measurements of buoyant of National Wave measuring System (RON - Rete Ondametrica Nazionale). The analysis shows that the north-weste…

MR2954311 (Review) 35R30 35J05 76Nxx Elschner, J. (D-WIAS); Hsiao, G. C. [Hsiao, George C.] (1-DE); Rathsfeld, A. [Rathsfeld, Andreas] (D-WIAS) Recon…

2011

Analytical results for 2-D non-rectilinear waveguides based on a Green's function

2008

We consider the problem of wave propagation for a 2-D rectilinear optical waveguide which presents some perturbation. We construct a mathematical framework to study such a problem and prove the existence of a solution for the case of small imperfections. Our results are based on the knowledge of a Green's function for the rectilinear case.

MR2997965 (Review) 37D45 Viana, R. L.; Lopes, S. R.; Szezech, J.D., Jr.; Caldas, I. L. Synchronization of chaos and the transition to wave turbulence…

2013

In this paper the authors analyze the onset of the wave turbulence in the spatially extended threewave interacting model by using the concept of synchronization. In order to work with a set of ordinary differential equations, they make a pseudo-spectral decomposition of the wave field and identify the onset of wave turbulence as the excitation of spatial modes in the presence of underlying temporally chaotic dynamics. Each spatial point is regarded as a nonlinear oscillator and the onset of wave turbulence is the point where the oscillators lose phase synchronization. The authors use an extremely sensitive complex-order parameter to estimate the threshold of weak turbulence and perform a Ly…

Non-Hermiticity in Quantum Physics

2022

The field of non-Hermitian Physics has attracted great attention over the last 23years, both from the in the physical and mathematical communities. From the physical point of view, non-Hermiticity was regarded as a phenomenological tool to describe open quantum systems. Besides this, the rising interest in this field comes especially from the possible exploitation of exceptional points for quantum technologies, and from the exotic topology arising in periodic non-Hermitian systems, connected to the so called non-Hermitian skin effect. From the mathematical point of view, the range of possible topics to investigate has been wide open, as dropping an hypothesis of a theory makes the mathemati…

A new approach for geological faults detection

2004

This paper will introduce a new approach, mainly based on wavelets transform and mathematical morphology, for the detection of geological faults in satellite and aerial photos. This can be useful for territorial analysis, digital cartography and the use of geographical information systems. The proposed method is fast enough and unsupervised. Different techniques will be compared and some examples on real data will be presented to indicate the applicability of these methods.

Anomaly detection using one-class SVM with wavelet packet decomposition

2011

Anomaly detection has become a popular research topic in the field of machine learning. Support vector machine is one anomaly detection technique and it is coming one the most widely used. In this research, anomaly detection is applied to road condition monitoring, especially pothole detection, using accelerometer data. The proposed concept includes data preprocessing, feature extraction, feature selection and classification. Accelerometer data was first filtered and segmented, after which features were extracted with frequency- and time-domain functions, with genetic programming and with wavelet packet decomposition. A classification model was built using support vector machine and the cal…

The mechanically based non-local elasticity: an overview of main results and future challenges

2013

The mechanically based non-local elasticity has been used, recently, in wider and wider engineering applications involving small-size devices and/or materials with marked microstructures. The key feature of the model involves the presence of non-local effects as additional body forces acting on material masses and depending on their relative displacements. An overview of the main results of the theory is reported in this paper.