Component technologies: Java Beans, COM, CORBA, RMI, EJB and the CORBA component model

This one-day tutorial is aimed at software engineering practitioners and researchers, who are familiar with objectoriented analysis, design and programming and want to obtain an overview of the technologies that are enabling component-based development. We introduce the idea of component-based development by defining the concept and providing its economic rationale. We describe how object-oriented programming evolved into local component models, such as Java Beans and distributed object technologies, such as the Common Object Request Broker Architecture (CORBA), Java Remote Method Invocation (RMI) and the Component Object Model (COM). We then address how these technologies matured into distributed component models, in partiuclar Enterprise Java Beans (EJB) and the CORBA Component Model (CCM). We give an assessment of the maturity of each of these technologies and sketch how they are used to build distributed architectures

Optical Studies of Er-doped Yttrium Aluminium Garnet Phosphor Materials

The need for materials application in solid-state lasers, medical devices, and optoelectronic devices has made the investigation of ceramic materials of increasing importance. A detail study of the optical properties of rare earth element typically from luminescent materials when intentionally doped inside the host materials and in particular crystal (such as YAG) is reported for the photoluminescence, power and lifetime measurement. The rare-earth dopants usually form trivalent lanthanide ions and the energy transfer and optical transitions involved originate from 4f-4f transitions of the ions and between these states and the host material. In order to understand the energy transfer processes in more detail we need to better understand the accompanying optical processes that give rise to the emission they display and it is this that forms the focus of the work presented. Following this second (and higher) order processes are considered that lead to upconversion in erbium-doped yttrium aluminum garnet (Er:YAG) materials

Chiral symmetry breaking in QED3{\rm QED}_{3} in presence of irrelevant interactions: a renormalization group study

Motivated by recent theoretical approaches to high temperature superconductivity, we study dynamical mass generation in three dimensional quantum electrodynamics ${\rm QED}_{3}$) in presence of irrelevant four-fermion quartic terms. The problem is reformulated in terms of the renormalization group flows of certain four-fermion couplings and charge, and then studied in the limit of large number of fermion flavors $N$. We find that the critical number of fermions $N_c$ below which the mass becomes dynamically generated depends continuously on a weak chiral-symmetry-breaking interaction. One-loop calculation in our gauge-invariant approach yields $N_{c0} = 6$ in pure ${\rm QED}_3$. We also find that chiral-symmetry-preserving mass cannot become dynamically generated in pure ${\rm QED}_{3}$.Comment: 7 pages, 7 figure

Localization of elastic waves in heterogeneous media with off-diagonal disorder and long-range correlations

Using the Martin-Siggia-Rose method, we study propagation of acoustic waves in strongly heterogeneous media which are characterized by a broad distribution of the elastic constants. Gaussian-white distributed elastic constants, as well as those with long-range correlations with non-decaying power-law correlation functions, are considered. The study is motivated in part by a recent discovery that the elastic moduli of rock at large length scales may be characterized by long-range power-law correlation functions. Depending on the disorder, the renormalization group (RG) flows exhibit a transition to localized regime in {\it any} dimension. We have numerically checked the RG results using the transfer-matrix method and direct numerical simulations for one- and two-dimensional systems, respectively.Comment: 5 pages, 4 figures, to appear in Phys. Rev. Let

Schubert calculus and Gelfand-Zetlin polytopes

We describe a new approach to the Schubert calculus on complete flag varieties using the volume polynomial associated with Gelfand-Zetlin polytopes. This approach allows us to compute the intersection products of Schubert cycles by intersecting faces of a polytope.Comment: 33 pages, 4 figures, introduction rewritten, Section 4 restructured, typos correcte

Anomalous Coherent Backscattering of Light from Opal Photonic Crystals

We studied coherent backscattering (CBS) of light from opal photonic crystals in air at different incident inclination angles, wavelengths and along various [hkl] directions inside the opals. Similar to previously obtained CBS cones from various random media, we found that when Bragg condition with the incident light beam is not met then the CBS cones from opals show a triangular line shape in excellent agreement with light diffusion theory. At Bragg condition, however, we observed a dramatic broadening of the opal CBS cones that depends on the incident angle and [hkl] direction. This broadening is explained as due to the light intensity decay in course of propagation along the Bragg direction {\em before the first} and {\em after the last} scattering events. We modified the CBS theory to incorporate the attenuation that results from the photonic band structure of the medium. Using the modified theory we extract from our CBS data the light mean free path and Bragg attenuation length at different [hkl]. Our study shows that CBS measurements are a unique experimental technique to explore photonic crystals with disorder, when other spectroscopical methods become ambiguous due to disorder-induced broadening.Comment: 10 pages, 5 figure

Localization in a random phase-conjugating medium

We theoretically study reflection and transmission of light in a one-dimensional disordered phase-conjugating medium. Using an invariant imbedding approach a Fokker-Planck equation for the distribution of the probe light reflectance and expressions for the average probabilities of reflection and transmission are derived. A new crossover length scale for localization of light is found, which depends on the competition between phase conjugation and disorder. For weak disorder, our analytical results are in good agreement with numerical simulations.Comment: RevTex, 4 pages, 4 figure

Enhanced Critical Field of Superconductivity at an Oxide Interface

The nature of superconductivity and its interplay with strong spin-orbit coupling at the KTaO3(111) interfaces remains a subject of debate. To address this problem, we grew epitaxial LaMnO3/KTaO3(111) heterostructures. We show that superconductivity is robust against the in-plane magnetic field, with the critical field of superconductivity reaching 25 T in optimally doped heterostructures. The superconducting order parameter is highly sensitive to carrier density. We argue that spin-orbit coupling drives the formation of anomalous quasiparticles with vanishing magnetic moment, providing the condensate significant immunity against magnetic fields beyond the Pauli paramagnetic limit. These results offer design opportunities for superconductors with extreme resilience against magnetic field