Six-body Light-Front Tamm-Dancoff approximation and wave functions for the massive Schwinger model

The spectrum of the massive Schwinger model in the strong coupling region is obtained by using the light-front Tamm-Dancoff (LFTD) approximation up to including six-body states. We numerically confirm that the two-meson bound state has a negligibly small six-body component. Emphasis is on the usefulness of the information about states (wave functions). It is used for identifying the three-meson bound state among the states below the three-meson threshold. We also show that the two-meson bound state is well described by the wave function of the relative motion.Comment: 19 pages, RevTeX, 7 figures are available upon request; Minor errors have been corrected; Final version to appear in Phys.Rev.

Interactive Virtual Laboratory for Experience with a Smart Bridge Test

Virtual laboratory experiments can be cost effective, convenient instructional resources that have appeal to a wide range of learning styles. Expensive, time-consuming laboratory tests can be experienced repeatedly and remotely using interactive simulations and original video footage or animations. A virtual experiment can incorporate meaningful exercises, procedural options, and background hyperlinks to create a comprehensive hands on environment. Also, it may be used as preliminary training for the actual experiment. An interactive LabVIEW-based laboratory for a load test simulation of an existing demonstration bridge was created. This smart truss bridge is instrumented with fiber optic strain sensors situated on the trusses. The user interface incorporates a synchronized image of the loaded bridge and a graph of the associated strains. A static display mode allows the choice of load placement and of data for single or multiple sensors. A continuous display mode shows the dynamic images of the bridge and strains on truss members. Options include the display of experimental data or of theoretical calculations. Hyperlinks give access to information on the sensors, the bridge construction, and the theoretical analysis. The program interface can also be used in the actual experiment to display data. The intended application is a laboratory for an interdisciplinary class on smart materials and sensors. The Lab VIEW program can be easily modified for tests on other structures such as a full-scale bridge

Dynamics of the Light-Cone Zero Modes: Theta Vacuum of the Massive Schwinger Model

The massive Schwinger model is quantized on the light cone with great care on the bosonic zero modes by putting the system in a finite (light-cone) spatial box. The zero mode of $A_{-}$ survives Dirac's procedure for the constrained system as a dynamical degree of freedom. After regularization and quantization, we show that the physical space condition is consistently imposed and relates the fermion Fock states to the zero mode of the gauge field. The vacuum is obtained by solving a Schr\"odinger equation in a periodic potential, so that the theta is understood as the Bloch momentum. We also construct a one-meson state in the fermion-antifermion sector and obtained the Schr\"odinger equation for it.Comment: 23 pages, RevTex, no figure

Intelligent Strain Sensing on a Smart Composite Wing using Extrinsic Fabry-Perot Interferometric Sensors and Neural Networks

Strain prediction at various locations on a smart composite wing can provide useful information on its aerodynamic condition. The smart wing consisted of a glass/epoxy composite beam with three extrinsic Fabry-Perot interferometric (EFPI) sensors mounted at three different locations near the wing root. Strain acting on the three sensors at different air speeds and angles-of-attack were experimentally obtained in a closed circuit wind tunnel under normal conditions of operation. A function mapping the angle of attack and air speed to the strains on the three sensors was simulated using feedforward neural networks trained using a backpropagation training algorithm. This mapping provides a method to predict the stall condition by comparing the strain available in real time and the predicted strain by the trained neural network

Detection of IUPAC and IUPAC-like chemical names

Motivation: Chemical compounds like small signal molecules or other biological active chemical substances are an important entity class in life science publications and patents. Several representations and nomenclatures for chemicals like SMILES, InChI, IUPAC or trivial names exist. Only SMILES and InChI names allow a direct structure search, but in biomedical texts trivial names and Iupac like names are used more frequent. While trivial names can be found with a dictionary-based approach and in such a way mapped to their corresponding structures, it is not possible to enumerate all IUPAC names. In this work, we present a new machine learning approach based on conditional random fields (CRF) to find mentions of IUPAC and IUPAC-like names in scientific text as well as its evaluation and the conversion rate with available name-to-structure tools

Renormal-order improvement of the Schwinger mass

The massive Schwinger model may be analysed by a perturbation expansion in the fermion mass. However, the results of this mass perturbation theory are sensible only for sufficiently small fermion mass. By performing a renormal-ordering, we arrive at a chiral perturbation expansion where the expansion parameter remains small even for large fermion mass. We use this renormal-ordered chiral perturbation theory for a computation of the Schwinger mass and compare our results with lattice computations.Comment: Latex file, 13 pages, 3 figures, needed macro: psbox.te

Ralstonia pickettii—innocent bystander or a potential threat?

ABSTRACTRalstonia pickettii can be isolated from water, soil and plants, and can also form part of the commensal flora of the oral cavity and the upper respiratory tract of healthy individuals. R. pickettii is an infrequent pathogen, but can cause infections, mainly of the respiratory tract, in immunocompromised and cystic fibrosis patients. It can be isolated from a variety of clinical specimens, including sputum, blood, wound infections, urine, ear and nose swabs, and cerebrospinal fluid. Resistance can occur to ciprofloxacin, trimethoprim–sulphamethoxazole, piperacillin–tazobactam, imipenem–cilastatin and ceftazidime. Early detection of R. pickettii allows prompt appropriate antimicrobial therapy with a favourable outcome, but removal of infected indwelling devices is mandatory

Zero Mode and Symmetry Breaking on the Light Front

We study the zero mode and the spontaneous symmetry breaking on the light front (LF). We use the discretized light-cone quantization (DLCQ) of Maskawa-Yamawaki to treat the zero mode in a clean separation from all other modes. It is then shown that the Nambu-Goldstone (NG) phase can be realized on the trivial LF vacuum only when an explicit symmetry-breaking mass of the NG boson $m_{\pi}$ is introduced. The NG-boson zero mode integrated over the LF must exhibit singular behavior $\sim 1/m_{\pi}^2$ in the symmetric limit $m_{\pi}\to 0$, which implies that current conservation is violated at zero mode, or equivalently the LF charge is not conserved even in the symmetric limit. We demonstrate this peculiarity in a concrete model, the linear sigma model, where the role of zero-mode constraint is clarified. We further compare our result with the continuum theory. It is shown that in the continuum theory it is difficult to remove the zero mode which is not a single mode with measure zero but the accumulating point causing uncontrollable infrared singularity. A possible way out within the continuum theory is also suggested based on the ``$\nu$ theory''. We finally discuss another problem of the zero mode in the continuum theory, i.e., no-go theorem of Nakanishi-Yamawaki on the non-existence of LF quantum field theory within the framework of Wightman axioms, which remains to be a challenge for DLCQ, ``$\nu$ theory'' or any other framework of LF theory.Comment: 60 pages, the final section has been expanded. A few minor corrections; version to be published in Phys. Rev.

Series Expansions for the Massive Schwinger Model in Hamiltonian lattice theory

It is shown that detailed and accurate information about the mass spectrum of the massive Schwinger model can be obtained using the technique of strong-coupling series expansions. Extended strong-coupling series for the energy eigenvalues are calculated, and extrapolated to the continuum limit by means of integrated differential approximants, which are matched onto a weak-coupling expansion. The numerical estimates are compared with exact results, and with finite-lattice results calculated for an equivalent lattice spin model with long-range interactions. Both the heavy fermion and the light fermion limits of the model are explored in some detail.Comment: RevTeX, 10 figures, add one more referenc