Single Gauge Research Articles

GLSM realizations of maps and intersections of Grassmannians and Pfaffians

In this paper we give gauged linear sigma model (GLSM) realizations of a number of geometries not previously presented in GLSMs. We begin by describing GLSM realizations of maps including Veronese and Segre embeddings, which can be applied to give GLSMs explicitly describing non-complete intersection constructions such as the intersection of one hypersurface with the image under some map of another. We also discuss GLSMs for intersections of Grassmannians and Pfaffians with one another, and with their images under various maps, which sometimes form exotic constructions of Calabi-Yaus, as well as GLSMs for other exotic Calabi-Yau constructions of Kanazawa. Much of this paper focuses on a specific set of examples of GLSMs for intersections of Grassmannians G(2, N ) with themselves after a linear rotation, including the Calabi-Yau case N = 5. One phase of the GLSM realizes an intersection of two Grassmannians, the other phase realizes an intersection of two Pfaffians. The GLSM has two nonabelian factors in its gauge group, and we consider dualities in those factors. In both the original GLSM and a double-dual, one geometric phase is realized perturbatively (as the critical locus of a superpotential), and the other via quantum effects. Dualizing on a single gauge group factor yields a model in which each geometry is realized through a simultaneous combination of perturbative and quantum effects.

Balancing anisotropic curvature with gauge fields in a class of shear-free cosmological models

We present a complete list of general relativistic shear-free solutions in a class of anisotropic, spatially homogeneous and orthogonal cosmological models containing a collection of n independent p-form gauge fields, where , in addition to standard ΛCDM matter fields modelled as perfect fluids. Here a (collection of) gauge field(s) balances anisotropic spatial curvature on the right-hand side of the shear propagation equation. The result is a class of solutions dynamically equivalent to standard FLRW cosmologies, with an effective curvature constant that depends both on spatial curvature and the energy density of the gauge field(s). In the case of a single gauge field (n = 1) we show that the only spacetimes that admit such solutions are the LRS Bianchi type III, Bianchi type VI0 and Kantowski–Sachs metric, which are dynamically equivalent to open (), flat () and closed () FLRW models, respectively. With a collection of gauge fields (n > 1) also Bianchi type II admits a shear-free solution (). We identify the LRS Bianchi type III solution to be the unique shear-free solution with a gauge field Hamiltonian bounded from below in the entire class of models.

Coupled dynamics in gluon mass generation and the impact of the three-gluon vertex

We present a detailed study of the subtle interplay transpiring at the level of two integral equations that are instrumental for the dynamical generation of a gluon mass in pure Yang-Mills theories. The main novelty is the joint treatment of the Schwinger-Dyson equation governing the infrared behavior of the gluon propagator and of the integral equation that controls the formation of massless bound-state excitations, whose inclusion is instrumental for obtaining massive solutions from the former equation. The self-consistency of the entire approach imposes the requirement of using a single value for the gauge coupling entering in the two key equations; its fulfilment depends crucially on the details of the three-gluon vertex, which contributes to both of them, but with different weight. In particular, the characteristic suppression of this vertex at intermediate and low energies enables the convergence of the iteration procedure to a single gauge coupling, whose value is reasonably close to that extracted from related lattice simulations.

Simulation of dynamic expansion, contraction, and connectivity in a mountain stream network

Abstract Headwater stream networks expand and contract in response to changes in stream discharge. The changes in the extent of the stream network are also controlled by geologic or geomorphic setting – some reaches go dry even under relatively wet conditions, other reaches remain flowing under relatively dry conditions. While such patterns are well recognized, we currently lack tools to predict the extent of the stream network and the times and locations where the network is dry within large river networks. Here, we develop a perceptual model of the river corridor in a headwater mountainous catchment, translate this into a reduced-complexity mechanistic model, and implement the model to examine connectivity and network extent over an entire water year. Our model agreed reasonably well with our observations, showing that the extent and connectivity of the river network was most sensitive to hydrologic forcing under the lowest discharges (Qgauge 10 L s−1) the extent of the network was relatively insensitive to hydrologic forcing and was instead determined by the network topology. We do not expect that the specific thresholds observed in this study would be transferable to other catchments with different geology, topology, or hydrologic forcing. However, we expect that the general pattern should be robust: the dominant controls will shift from hydrologic forcing to geologic setting as discharge increases. Furthermore, our method is readily transferable as the model can be applied with minimal data requirements (a single stream gauge, a digital terrain model, and estimates of hydrogeologic properties) to estimate flow duration or connectivity along the river corridor in unstudied catchments. As the available information increases, the model could be better calibrated to match site-specific observations of network extent, locations of dry reaches, or solute break through curves as demonstrated in this study. Based on the low initial data requirements and ability to later tune the model to a specific site, we suggest example applications of this parsimonious model that may prove useful to both researchers and managers.

A strain gage technique for mode I notch stress intensity factor of sharp V-notched configurations

A simple and robust single strain gage technique for accurate measurement of mode I notch stress intensity factor (NSIF) for sharp V-notched configurations has been proposed. The technique is supported by strong theoretical foundation, and it allows the strain gage to be placed reasonably away from the notch tip thus avoiding various problems associated with singularities. Importantly, in contrast to the available techniques, the present strain gage technique also prescribes proper radial locations (optimal locations) for the strain gage which are extremely useful in accurate measurement of NSIFs. A general theory and procedure has been developed for the estimation of these gage locations a priori for any given sharp V-notched configuration. These locations are shown to be dependent on the notch angle and notch length to width ratio. Experiments have been conducted using linear strain gages of 1 mm gage length and the results show that accurate NSIFs can be measured using the proposed single strain gage technique. The numerical results of the present investigation clearly show that very accurate (of the order of less than 1% error) mode I NSIF can be measured using the proposed single strain gage technique if the gages are placed at the optimal locations. The present results also demonstrate that highly inaccurate (of the order of 45% error) and unacceptable NSIFs would result if the gages are placed at non-optimal gage locations.

The Wet-Antenna Effect—A Factor to be Considered in Future Communication Networks

An accurate design of the fading margin in wireless communication networks requires good modeling of the relationship between the rain rate and the attenuation. In this paper, we discuss the effect of the wet antenna (WA) on the fading margin. We claim that this effect is not negligible in commercial $E$ -band (i.e., 60–90 GHz) technologies, where the microwave links are relatively short and the sensitivity of the signal to attenuation induced by rain is significant. Consequently, we propose a method for estimating the WA-induced attenuation, so it can be incorporated in the current models. Different from previous studies, our proposed method can be implemented on received signal level measurements, which are standardly produced by commercial microwave links (CMLs) and a single rain gauge. We demonstrate our results using actual measurements taken by 73 GHz CMLs of about 1 km, provided by Ericsson.

Utilization of Global Precipitation Datasets in Data Limited Regions: A Case Study of Kilombero Valley, Tanzania

This study explored the potential for bias correction of global precipitation datasets (GPD) to support streamflow simulation for water resource management in data limited regions. Two catchments, 580 km2 and 2530 km2, in the Kilombero Valley of central Tanzania were considered as case studies to explore three GPD bias correction methods: quantile mapping (QM), daily percentages (DP) and a model based (ModB) bias correction. The GPDs considered included two satellite rainfall products, three reanalysis products and three interpolated observed data products. The rainfall-runoff model HBV was used to simulate streamflow in the two catchments using (1) observed rain gauge data; (2) the original GPDs and (3) the bias-corrected GPDs as input. Results showed that applying QM to bias correction based on limited observed data tends to aggravate streamflow simulations relative to not bias correcting GPDs. This is likely due to a potential lack of representativeness of a single rain gauge observation at the scale of a hydrological catchment for these catchments. The results also indicate that there may be potential benefits in combining streamflow and rain gauge data to bias correct GPDs during the model calibration process within a hydrological modeling framework.

Impact of Spatiotemporal Characteristics of Rainfall Inputs on Integrated Catchment Dissolved Oxygen Simulations

Integrated Catchment Modelling aims to simulate jointly urban drainage systems, wastewater treatment plant and rivers. The effect of rainfall input uncertainties in the modelling of individual urban drainage systems has been discussed in several studies already. However, this influence changes when simultaneously simulating several urban drainage subsystems and their impact on receiving water quality. This study investigates the effect of the characteristics of rainfall inputs on a large-scale integrated catchment simulator for dissolved oxygen predictions in the River Dommel (The Netherlands). Rainfall products were generated with varying time-aggregation (10, 30 and 60 min) deriving from different sources of data with increasing spatial information: (1) Homogeneous rainfall from a single rain gauge; (2) block kriging from 13 rain gauges; (3) averaged C-Band radar estimation and (4) kriging with external drift combining radar and rain gauge data with change of spatial support. The influence of the different rainfall inputs was observed at combined sewer overflows (CSO) and dissolved oxygen (DO) dynamics in the river. Comparison of the simulations with river monitoring data showed a low sensitivity to temporal aggregation of rainfall inputs and a relevant impact of the spatial scale with a link to the storm characteristics to CSO and DO concentration in the receiving water.

Mechanical strain to maxillary incisors during direct laryngoscopy

BackgroundWhile most Direct laryngoscopy leads to dental injury in 25–39% of cases. Dental injury occurs when the forces and impacts applied to the teeth exceed the ability of the structures to dissipate energy and stress. The purpose of this study was to measure strain, (which is the change produced in the length of the tooth by a force applied to the tooth) strain rate, and strain-time integral to the maxillary incisors and determine if they varied by experience, type of blade, or use of an alcohol protective pad (APP).MethodsA mannequin head designed to teach and test intubation was instrumented with eight single axis strain gauges placed on the four maxillary incisors: four on the facial or front surface of the incisors and four on the lingual or back, near the insertion of the incisor in the gums to measure bending strain as well as compression. Anesthesiology faculty, residents, and certified registered nurse anesthetists intubated with Macintosh and Miller blades with and without APP. Using strain-time curves, the maximum strain, strain rate, and strain time integral were calculated.ResultsAcross the 92 subjects, strain varied 8–12 fold between the 25th and 75th percentiles for all four techniques, but little by experience, while strain rate and strain integral varied 6–13 fold and 15–26 fold, respectively, for the same percentiles. Intubators who had high strain values with one blade tended to have high strains with the other blade with and without the APP (all pairwise correlation rho = 0.42–0.63).ConclusionsStrain varies widely by intubator and that the use of the APP reduces strain rate which may decrease the risk of or the severity of dental injury.

Conformal phase diagram of complete asymptotically free theories

We investigate the ultraviolet and infrared fixed point structure of gauge-Yukawa theories featuring a single gauge coupling, Yukawa coupling and scalar self-coupling. Our investigations are performed using the two loop gauge beta function, one loop Yukawa beta function, and one loop scalar beta function. We provide the general conditions that the beta function coefficients must abide for the theory to be complete asymptotically free while simultaneously possessing an infrared stable fixed point. We also uncover special trajectories in coupling space along which some couplings are both asymptotically safe and infrared conformal.

Non-perturbatively gauge-fixed compact U(1) lattice gauge theory

An extensive study of the compact U(1) lattice gauge theory with a higher derivative gauge-fixing term and a suitable counter-term has been undertaken to determine the nature of the possible continuum limits for a wide range of the parameters, especially at strong gauge couplings (g > 1), adding to our previous study at a single gauge coupling g = 1.3 [1]. Our major conclusion is that a continuum limit of free massless photons(with the redundant pure gauge degrees of freedom decoupled) is achieved at any gauge coupling, not necessarily small, provided the coefficient tilde{kappa} of the gauge-fixing term is sufficiently large. In fact, the region of continuous phase transition leading to the above physics in the strong gauge coupling region is found to be analytically connected to the point g = 0 and tilde{kappa}to infty where the classical action has a global unique minimum, around which weak coupling perturbation theory in bare parameters is defined, controlling the physics of the whole region. A second major conclusion is that, local algorithms like Multihit Metropolis fail to produce faithful field configurations with large values of the coefficient tilde{kappa} of the higher derivative gauge-fixing term and at large lattice volumes. A global algorithm like Hybrid Monte Carlo, although at times slow to move out of metastabilities, generally is able to produce faithful configurations and has been used extensively in the current study.

More large N limits of 3d gauge theories

In this paper we study the large N solution to matrix models describing the partition functions of 3d supersymmetric gauge theories on . The model we focus on has a single gauge group and fundamental fields, whose number scales with N, also known as the Veneziano limit. The novel point in our model is our choice of masses for the fundamental fields. Instead of vanishing or fixed masses, we consider a linear distribution. We show that the model can still be solved by standard large N techniques and explore the different phases of the model. We also comment about other natural mass distributions.

Strings in Singular Space-Times and Their Universal Gauge Theory

We study the propagation of bosonic strings in singular target space-times. For describing this, we assume this target space to be the quotient of a smooth manifold $M$ by a singular foliation ${\cal F}$ on it. Using the technical tool of a gauge theory, we propose a smooth functional for this scenario, such that the propagation is assured to lie in the singular target on-shell, i.e. only after taking into account the gauge invariant content of the theory. One of the main new aspects of our approach is that we do not limit ${\cal F}$ to be generated by a group action. We will show that, whenever it exists, the above gauging is effectuated by a single geometrical and universal gauge theory, whose target space is the generalized tangent bundle $TM\oplus T^*M$.

Constraining SWAT Calibration with Remotely Sensed Evapotranspiration Data

AbstractHistorically, many watershed studies have been based on using the streamflow flux, typically from a single gauge at the basin's outlet, to support calibration. In this setting, there is great potential for equifinality of parameters during the optimization process, especially for parameters that are not directly related to streamflow. Therefore, some of the optimal parameter values achieved during the autocalibration process may be physically unrealistic. In recent decades a vast array of data from land surface models and remote sensing platforms can help to constrain hydrologic fluxes such as evapotranspiration (ET). While the spatial resolution of these ancillary datasets varies, the continuous spatial coverage of these gridded datasets provides flux measurements across the entire basin, in stark contrast to point‐based streamflow data. This study uses Global Land Evaporation: the Amsterdam Model data to constrain Soil and Water Assessment Tool parameter values associated with ET to a more physically realistic range. The study area is the Little Washita River Experimental Watershed, in southern Oklahoma. Traditional objective metrics such as the Nash‐Sutcliffe coefficients record no performance improvement after application of this method. However, there is a dramatic increase in the number of days with receding flow where simulations match observed streamflow.

Numerical investigation of explosive bare charge equivalent weight

Peak overpressure and impulse are the most important parameters in the explosive performance estimation. Available models commonly consider trinitrotoluene explosive as the standard charge. In this article, the trinitrotoluene equivalency factor is studied through verified one-dimensional numerical simulations. The equivalency factors for impulse and overpressure are different and found to be constant with the scaled distance (3–40 m/kg1/3), which means that a unique value for the equivalency factor is suitable for the equivalency factor calculation for each distance. Comparison of the equivalency factor with available models shows that it strongly depends on the internal energy ratio of the explosive in interest, relative to trinitrotoluene, and a new formula for equivalency factor for overpressure is proposed. A verified simulation method is presented in which the explosive is modeled with an equivalent “air bubble” with the same internal energy and ideal gas equation of state. A new approach using the energy flux density calculation is presented to calculate the equivalency factor for impulse and overpressure from a single gauge measurement of overpressure-time history, at a specific distance.

Double-real corrections at {{mathcal {O}}(alpha alpha _s)},to single gauge boson production

We consider the {{mathcal {O}}(alpha alpha _s)},corrections to single on-shell gauge boson production at hadron colliders. We concentrate on the contribution of all the subprocesses where the gauge boson is accompanied by the emission of two additional real partons and we evaluate the corresponding total cross sections. The latter are divergent quantities, because of soft and collinear emissions, and are expressed as Laurent series in the dimensional regularization parameter. The total cross sections are evaluated by means of reverse unitarity, i.e. expressing the phase-space integrals in terms of two-loop forward box integrals with cuts on the final-state particles. The results are reduced to a combination of master integrals, which eventually are evaluated in terms of generalized polylogarithms. The presence of internal massive lines in the Feynman diagrams, due to the exchange of electroweak gauge bosons, causes the appearance of 14 master integrals which were not previously known in the literature and have been evaluated via differential equations.

Experimental determination of mode I stress intensity factor in orthotropic materials using a single strain gage

This paper presents a robust technique for experimental determination of mode I stress intensity factor in orthotropic materials using only a single strain gage. Theoretical foundation and finite element based analysis leading to the selection of the angular orientation and position of the strain gage for accurate estimation of KI in orthotropic materials is presented here. Applicability of the proposed method has been established through experiments conducted on edge-cracked carbon-epoxy laminates. Results show that the present single strain gage experiments yield accurate values of KI when strain gage locations are selected as per the criteria set by the proposed approach.

Some pictures of the history of automotive instrumentation

AbstractThe first in vehicle instrument was the speedometer. It was invented by Otto Schulze in 1902. Until then, drivers had to estimate their speed. The speedometer was followed by an alcohol temperature gauge. A few warning lamps surveyed the most important vehicle functions. Later, single gauges like radiator temperature, fuel gauge, and revolution counter were added to the instrumentation. They were superseded by instrument clusters combining several instruments in one housing. Even though the appearance of the instrument cluster did not change significantly from the early days, there was a steady development of the intelligence behind the panel. This huge amount of information could only be handled by graphic displays. When navigation systems came into our cars, a larger graphic display was needed. It found place in the center console. In parallel, the price decline in the computer market and the availability of high‐performing graphic hardware and software made it possible to enhance the classical functions of the instrument board to an interactive multifunctional information panel, with the dashboard being the main interface between car and driver. The windshield was the third zone where information could be placed in a favorable reading position minimizing eyes off the road time. As a consequent evolution step, augmented reality head‐up displays will soon dominate the information center of premium‐class vehicles.

Worldline Path-Integral Representations for Standard Model Propagators and Effective Actions

We develop the formalism to do worldline calculations relevant for the Standard Model. For that, we first figure out the worldline representations for the free propagators of massless chiral fermions of a single generation and gauge bosons of the Standard Model. Then we extend the formalism to the massive and dressed cases for the fermions and compute the QED vertex. We then go over fermionic one-loop effective actions and anomalies. To our knowledge, in the places where there has been an attempt at deriving the gauge boson propagator, the derivation is somewhat contrived, and we believe our derivation is more straightforward. Moreover, our incorporation of internal degrees of freedom is novel and sports some new features. The derivation of the QED vertex is also new. The treatment of the fermionic one-loop effective actions leads to a particularly economical derivation of chiral anomalies and the gauge anomaly freedom in the Standard Model, improving upon the state of the art in the literature. The appropriate worldline formalism developed thus sets the stage for Standard Model calculations beyond the tree and one-loop cases that incorporate Bern-Kosower type formulae for multiloop amplitudes, relevant for processes at the LHC.

Precision measurements and searches with single and multiple gauge bosons with the ATLAS detector

The ATLAS collaboration has carried out a set of measurements at center-of-mass energies of 8 TeV and 13 TeV, which provide stringent tests of the electroweak sector of the Standard Model, specifically on single, di- and multi-boson production cross sections.This paper gives a review of the latest results on these topics from ATLAS. It covers the inclusive production measurement of single W and Z/γ * bosons and the measurement of the complete set of coefficients that describe the angular distributions of the decay leptons in Z events. Also it includes the review of the inclusive and differential cross sections measurements for the production of two heavy gauge bosons (WW , WZ , ZZ ) in the leptonic channels, the production measurement of the Z boson in association with one or two photons and the search for the WZ production via vector-boson scattering. These measurements are compared to (N)NLO predictions of the Standard Model and provide model-independent constraints on the so-called «new physics», by setting the limits on the anomalous triple or quartic gauge-boson couplings.