Monopole Percolation in the Compact Abelian Higgs Model

We have studied the monopole-percolation phenomenon in the four dimensional Abelian theory that contains compact U(1) gauge fields coupled to unitary norm Higgs fields. We have determined the location of the percolation transition line in the plane $(\beta_g, \beta_H)$. This line overlaps the confined-Coulomb and the confined-Higgs phase transition lines, originated by a monopole-condensation mechanism, but continues away from the end-point where this phase transition line stops. In addition, we have determined the critical exponents of the monopole percolation transition away from the phase transition lines. We have performed the finite size scaling in terms of the monopole density instead of the coupling, because the density seems to be the natural parameter when dealing with percolation phenomena.Comment: 13 pages. REVTeX. 16 figs. included using eps

Determination of partial photoionisation cross sections of methyl bromide in the first autoionisation range by use of spin polarisation photoelectron spectroscopy

Schäfers F, Baig MA, Heinzmann U. Determination of partial photoionisation cross sections of methyl bromide in the first autoionisation range by use of spin polarisation photoelectron spectroscopy. Journal of Physics B: Atomic, Molecular and Optical Physics. 1983;16(1):L1-L6.Using recent experimental data on photoelectron spin polarisation combined with the high-resolution spectrum of methyl bromide, which has also been recently reported, the partial photoionisation cross sections for the ionisation of CH3Br from the 4 pi ground-state orbital into the energy degenerate continua epsilon sigma , epsilon pi and epsilon delta have been determined separately. Quantitative results, obtained for the autoionising resonances between 116 and 118 nm, are reported and discussed

Entanglement assisted alignment of reference frames using a dense covariant coding

We present a procedure inspired by dense coding, which enables a highly efficient transmission of information of a continuous nature. The procedure requires the sender and the recipient to share a maximally entangled state. We deal with the concrete problem of aligning reference frames or trihedra by means of a quantum system. We find the optimal covariant measurement and compute the corresponding average error, which has a remarkably simple close form. The connection of this procedure with that of estimating unitary transformations on qubits is briefly discussed.Comment: 4 pages, RevTeX, Version to appear in PR

Prevalence of helicobacter pylori in chronic gastritis: A cross sectional study

INTRODUCTION: Helicobacter pylori (H. pylori) is one of the most common human infections worldwide particularly in the developing countries. It has been established as etiology of chronic gastritis and peptic ulcer disease, gastric adenocarcinoma and mucosal associated lymphoid tissue lymphoma (MALT). During this decade, there have been some reports showing a decline in global prevalence of H. pylori infection and peptic diseases including many Asian countries. Hence to determine prevalence of Helicobacter pylori infection in dyspeptic patients, this descriptive, study was carried out at the Endoscopy sub-unit of the Surgery Department from December 2016 to September 2017. MATERIALS AND METHODS: Study was underwent in patients coming to Department of General Surgery OPD with complaints of dyspepsia for more than 6 months, in Govt. Kilpauk Medical College and Hospital Chennai. Eighty seven (87) patients between 20-60 years of age with symptoms of dyspepsia are selected. RESULTS: Of 87 patients, 62% of individuals had chronic gastritis and 50% of individuals are infected with H. pylori. Majority of H. pylori infected individuals are in the age group of 5th decade (56.7%). Gender, alcohol, smoking doesn’t show any correlation with H. pylori individual. Most endoscopic finding is Gastritis (62.06%). The prevalence of H. pylori is more in tobacco users (73.7%) and it is statistically significant. The prevalence of H. pylori in chronic gastritis is 70.4% which is statistically significant. CONCLUSION: The study was done with the objective to find the prevalence of H. pylori in chronic gastritis. The study showed that 62.1% of study population were having chronic gastritis and 50.6% of individuals are infected with H. pylori. It also shown that 70.4% of individuals in chronic gastritis are affected with H. pylori. This study shows the significant relationship between chronic gastritis and H. pylori infection

String tension in gonihedric 3D Ising models

For the 3D gonihedric Ising models defined by Savvidy and Wegner the bare string tension is zero and the energy of a spin interface depends only on the number of bends and self-intersections, in antithesis to the standard nearest-neighbour 3D Ising action. When the parameter kappa weighting the self-intersections is small the model has a first order transition and when it is larger the transition is continuous. In this paper we investigate the scaling of the renormalized string tension, which is entirely generated by fluctuations, using Monte Carlo simulations This allows us to obtain an estimate for the critical exponents alpha and nu using both finite-size-scaling and data collapse for the scaling function.Comment: Latex + postscript figures. 8 pages text plus 7 figures, spurious extra figure now removed

Chiral transition and monopole percolation in lattice scalar QED with quenched fermions

We study the interplay between topological observables and chiral and Higgs transitions in lattice scalar QED with quenched fermions. Emphasis is put on the chiral transition line and magnetic monopole percolation at strong gauge coupling. We confirm that at infinite gauge coupling the chiral transition is described by mean field exponents. We find a rich and complicated behaviour at the endpoint of the Higgs transition line which hampers a satisfactory analysis of the chiral transition. We study in detail an intermediate coupling, where the data are consistent both with a trivial chiral transition clearly separated from monopole percolation and with a chiral transition coincident with monopole percolation, and characterized by the same critical exponent $\nu \simeq 0.65$. We discuss the relevance (or lack thereof) of these quenched results to our understanding of the \chupiv\ model. We comment on the interplay of magnetic monopoles and fermion dynamics in more general contexts.Comment: 29 pages, 13 figures included, LaTeX2e (elsart

First-order transition of tethered membranes in 3d space

We study a model of phantom tethered membranes, embedded in three-dimensional space, by extensive Monte Carlo simulations. The membranes have hexagonal lattice structure where each monomer is interacting with six nearest-neighbors (NN). Tethering interaction between NN, as well as curvature penalty between NN triangles are taken into account. This model is new in the sense that NN interactions are taken into account by a truncated Lennard-Jones potential including both repulsive and attractive parts. The main result of our study is that the system undergoes a first-order crumpling transition from low temperature flat phase to high temperature crumpled phase, in contrast with early numerical results on models of tethered membranes.Comment: 5 pages, 6 figure

Review: Inelastic Constitutive Modeling: Polycrystalline Materials

This article provides a literature review that details the development of inelastic constitutive modeling as it relates to polycrystalline materials. This review distinguishes between inelastic constitutive models that account for nonlinear behavior at the microstructural level, time-independent classic plasticity models, and time-dependent unified models. Particular emphasis is placed on understanding the underlying theoretical framework for unified viscoplasticity models where creep and classical plasticity behavior are considered the result of applied boundary conditions instead of separable rates representing distinct physical mechanisms. This article establishes a clear understanding of the advantages of the unified approach to improve material modeling. This review also discusses recent topics in constitutive modeling that offer new techniques that bridge the gap between the microstructure and the continuum

Optical modeling of four Fresnel-based high-CPV units

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordHigh Concentrator Photovoltaic (HCPV) units are typically based on the use of Fresnel lenses, refractive secondary optical elements (SOE), and triple-junction (TJ) solar cells. In this work, a detailed optical modeling is applied to analyze the performance of four Fresnel-based HCPV units equipped with different refractive SOEs while considering the subcells current density generation. Wavelength-dependent material properties are utilized while simulating the optical performance. The spectral response of a typical TJ solar cell is also included. This modeling allows to establish the subcell current limitation and the spectral matching ratio, SMR, values in each case. The following SOEs have been used for simulating the HCPV units: (i) Dielectric-cross compound-parabolic-concentrator (DCCPC), (ii) (SIngle-Lens-Optical element) SILO-Pyramid, (iii) Refractive truncated pyramid (RTP) and, (iv) Trumpet. Results show that the HCPV units with SOEs RTP and Trumpet, exhibit bottom subcell current limitation and lowest optical polychromatic efficiency, this is partly due to the irradiance absorption in the bottom cell spectral region and longer optical path length of the concentrated rays within the SOE material. In the case of the HCPV unit with the DCCPC SOE, top and bottom subcells limit the current generation alternatively depending on the misalignment angle of the HCPV unit respect to the simulated sunrays. None of the SMR parameters are equal to 1 under normal alignment of the HCPV units. The short-circuit current density distributions for each subcell in each case are studied under normal alignment and under 1° of misalignment angle.European Regional Development Fund (ERDF) and Spanish Economy Ministry (ENE2013-45242-R and ENE2016-78251-R); Universidad de Jaén (UJA) and Caja Rural de Jaén (UJA2015/07/01). Financial support provided by the Universidad de Jaén Doctoral School