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A new functional renormalization group equation for Hamiltonian Yang-Mills theory in Coulomb gauge is presented and solved for the static gluon and ghost propagators under the assumption of ghost dominance. The results are compared to those obtained in the variational approach.
As computational models penetrate clinical care and drive healthcare policy decisions, there is increasing need to communicate that model creation and testing follows reasonable credible practice. Although verification and validation have been generally accepted as significant components of a model’s credibility, they cannot be assumed to equate to a holistic credible practice, which includes activities that can impact comprehension and in-depth examination inherent in the development and reuse of the models. This presentation introduces the Ten Rules for credible practice of modeling and simulation in healthcare developed from a comparative multidisciplinary analysis and practitioner survey. These rules establish a unified conceptual framework for modeling and simulation design, implementation, evaluation, dissemination and usage across the modeling and simulation life-cycle. Although some of these are common sense guidelines, many are often missed or misconstrued, even by seasoned practitioners.
Degrees of rate control (DRC), apparent activation energies, and apparent reaction orders are established local sensitivity diagnostics for interpreting microkinetic models, but applying them routinely to large mechanisms often requires substantial reaction-specific bookkeeping, perturbation design, and postprocessing. Here, in this study, we present a unified derivative-based workflow that evaluates these quantities from a single compiled reaction-network model and target-rate definition. For any user-provided microkinetic model, the workflow compiles the mechanism into stoichiometrically consistent mass-action rate equations, solves the surface dynamics, and uses automatic differentiation to compute sensitivities with respect to rate constants, temperature, and gas partial pressures. By combining their calculations in the same framework, the workflow clearly demonstrates the relationships between different DRCs and the apparent activation energy. Using existing examples of propylene partial oxidation and methane oxidation on Pd(100), we verify expected transient redistribution of rate control, distinguish net Campbell DRCs from one-sided directional sensitivities, and show how apparent activation energy can be reconstructed either from one-sided DRCs or from state-based DRCs while critical mechanistic insights are obtained consistently. In the methane oxidation case, a pathway-subset test further illustrates how a simplified mechanism preserves key kinetic signatures of a full model, showing the potential of our user-friendly tool for model construction beyond kinetic analysis.
Whenever one attempts to include the gravitational force in models of quantized elementary particles, a spooky kind of non-locality appears to emerge, either because attempts to renormalize the theory tend to violate unitarity, or because attempts to understand quantum mechanics in terms of some deterministic underlying theory also appear to require some spooky non-locality. In contrast, the only tested particle theory, the Standard Model, is perfectly local. Different from the Standard Model, Quantum Gravity suggests that physically independent degrees of freedom are denumerable. To get a different intuitive picture of what is going in, we take a new look at the role of black holes. It is suggested to reduce the local scale parameters to be locally unobservable, which would make it easier to understand the back reaction of Hawking radiation on the space-time metric. New approaches to Quantum Mechanics appear to allow for an interpretation in terms of a local, deterministic model, to be combined with General Relativity.
Automation of Space Station functions and activities, particularly those involving robotic capabilities with interactive or supervisory human control, is a complex, multi-disciplinary systems design problem. A wide variety of applications using autonomous control can be found in the literature, but none of them seem to address the problem in general. All of them are designed with a specific application in mind. In this report, an abstract model is described which unifies the key concepts underlying the design of automated systems such as those studied by the aerospace contractors. The model has been kept as general as possible. The attempt is to capture all the key components of autonomous systems. With a little effort, it should be possible to map the functions of any specific autonomous system application to the model presented here.
Automation of Space Station functions and activities, particularly those involving robotic capabilities with interactive or supervisory human control, is a complex, multi-disciplinary systems design problem. A wide variety of applications using autonomous control can be found in the literature, but none of them seem to address the problem in general. All of them are designed with a specific application in mind. In this report, an abstract model is described which unifies the key concepts underlying the design of automated systems such as those studied by the aerospace contractors. The model has been kept as general as possible. The attempt is to capture all the key components of autonomous systems. With a little effort, it should be possible to map the functions of any specific autonomous system application to the model presented here.
The Carbon Capture Simulation Initiative (CCSI) is a partnership among national laboratories, industry and academic institutions that is developing and deploying state-of-the-art computational modeling and simulation tools to accelerate the commercialization of carbon capture technologies from discovery to development, demonstration, and ultimately the widespread deployment to hundreds of power plants. The CCSI Toolset will provide end users in industry with a comprehensive, integrated suite of scientifically validated models, with uncertainty quantification (UQ), optimization, risk analysis and decision making capabilities. The CCSI Toolset incorporates commercial and open-source software currently in use by industry and is also developing new software tools as necessary to fill technology gaps identified during execution of the project. Ultimately, the CCSI Toolset will (1) enable promising concepts to be more quickly identified through rapid computational screening of devices and processes; (2) reduce the time to design and troubleshoot new devices and processes; (3) quantify the technical risk in taking technology from laboratory-scale to commercial-scale; and (4) stabilize deployment costs more quickly by replacing some of the physical operational tests with virtual power plant simulations. CCSI is led by the National Energy Technology Laboratory (NETL) and leverages the Department of Energy (DOE) national laboratories’ core strengths in modeling and simulation, bringing together the best capabilities at NETL, Los Alamos National Laboratory (LANL), Lawrence Berkeley National Laboratory (LBNL), Lawrence Livermore National Laboratory (LLNL), and Pacific Northwest National Laboratory (PNNL). The CCSI’s industrial partners provide representation from the power generation industry, equipment manufacturers, technology providers and engineering and construction firms. The CCSI’s academic participants (Carnegie Mellon University, Princeton University, West Virginia University, Boston University and the University of Texas at Austin) bring unparalleled expertise in multiphase flow reactors, combustion, process synthesis and optimization, planning and scheduling, and process control techniques for energy processes. During Fiscal Year (FY) 13, CCSI announced the initial release of its first set of computational tools and models during the October 2012 meeting of its Industry Advisory Board. This initial release led to five companies licensing the CCSI Toolset under a Test and Evaluation Agreement this year. By the end of FY13, the CCSI Technical Team had completed development of an updated suite of computational tools and models. The list below summarizes the new and enhanced toolset components that were released following comprehensive testing during October 2013. 1. FOQUS. Framework for Optimization and Quantification of Uncertainty and Sensitivity. Package includes: FOQUS Graphic User Interface (GUI), simulation-based optimization engine, Turbine Client, and heat integration capabilities. There is also an updated simulation interface and new configuration GUI for connecting Aspen Plus or Aspen Custom Modeler (ACM) simulations to FOQUS and the Turbine Science Gateway. 2. A new MFIX-based Computational Fluid Dynamics (CFD) model to predict particle attrition. 3. A new dynamic reduced model (RM) builder, which generates computationally efficient RMs of the behavior of a dynamic system. 4. A completely re-written version of the algebraic surrogate model builder for optimization (ALAMO). The new version is several orders of magnitude faster than the initial release and eliminates the MATLAB dependency. 5. A new suite of high resolution filtered models for the hydrodynamics associated with horizontal cylindrical objects in a flow path. 6. The new Turbine Science Gateway (Cluster), which supports FOQUS for running multiple simulations for optimization or UQ using a local computer or cluster. 7. A new statistical tool (BSS-ANOVA-UQ) for calibration and validation of CFD models. 8. A new basic data submodel in Aspen Plus format for a representative high viscosity capture solvent, 2-MPZ system. 9. An updated RM tool for CFD (REVEAL) that can create a RM from MFIX. A new lightweight, stand-alone version will be available in late 2013. 10. An updated RM integration tool to convert the RM from REVEAL into a CAPE-OPEN or ACM model for use in a process simulator. 11. An updated suite of unified steady-state and dynamic process models for solid sorbent carbon capture included bubbling fluidized bed and moving bed reactors. 12. An updated and unified set of compressor models including steady-state design point model and dynamic model with surge detection. 13. A new framework for the synthesis and optimization of coal oxycombustion power plants using advanced optimization algorithms. This release focuses on modeling and optimization of a cryogenic air separation unit (ASU). 14. A new technical risk model in spreadsheet format. 15. An updated version of the sorbent kinetic/equilibrium model for parameter estimation for the 1st generation sorbent model. 16. An updated process synthesis superstructure model to determine optimal process configurations utilizing surrogate models from ALAMO for adsorption and regeneration in a solid sorbent process. 17. Validation models for NETL Carbon Capture Unit utilizing sorbent AX. Additional validation models will be available for sorbent 32D in 2014. 18. An updated hollow fiber membrane model and system example for carbon capture. 19. An updated reference power plant model in Thermoflex that includes additional steam extraction and reinjection points to enable heat integration module. 20. An updated financial risk model in spreadsheet format.
For a polymorphic (multi-phase) material, such as Ce, the unified analytic melt-shear model describes both cold (T = 0) shear modulus, G, and melting temperature, Tm, as functions of density
In the wake of the Columbia accident, the NASA-STD-7009 [1] credibility assessment was developed as a unifying platform to describe model credibility and the uncertainties in its modeling predictions. This standard is now being adapted by NASAs Human Research Program to cover a wide range of numerical models for human research. When used properly, the standard can improve the process of code development by encouraging the use of best practices. It can also give management more insight in making informed decisions through a better understanding of the models capabilities and limitations.To a newcomer, the abstractions presented in NASA-STD-7009 and the sheer volume of information that must be absorbed can be overwhelming. This talk is aimed at describing the credibility assessment, which is the heart of the standard, in plain terms. It will outline how to develop a credibility assessment under the standard. It will also show how to quickly interpret the graphs and tables that result from the assessment and how to drill down from the top-level view to the foundation of the assessment. Finally, it will highlight some of the resources that are available for further study.
A simple six-parameter {Lambda}CDM model provides a successful fit to WMAP data. This holds both when the WMAP data are analyzed alone or in combination with other cosmological data. Even so, it is appropriate to examine the data carefully to search for hints of deviations from the now standard model of cosmology, which includes inflation, dark energy, dark matter, baryons, and neutrinos. The cosmological community has subjected the WMAP data to extensive and varied analyses. While there is widespread agreement as to the overall success of the six-parameter {Lambda}CDM model, various 'anomalies' have been reported relative to that model. In this paper we examine potential anomalies and present analyses and assessments of their significance. In most cases we find that claimed anomalies depend on posterior selection of some aspect or subset of the data. Compared with sky simulations based on the best-fit model, one can select for low probability features of the WMAP data. Low probability features are expected, but it is not usually straightforward to determine whether any particular low probability feature is the result of the a posteriori selection or non-standard cosmology. Hypothesis testing could, of course, always reveal an alternative model that is statistically favored, but there is currently no model that is more compelling. We find that two cold spots in the map are statistically consistent with random cosmic microwave background (CMB) fluctuations. We also find that the amplitude of the quadrupole is well within the expected 95% confidence range and therefore is not anomalously low. We find no significant anomaly with a lack of large angular scale CMB power for the best-fit {Lambda}CDM model. We examine in detail the properties of the power spectrum data with respect to the {Lambda}CDM model and find no significant anomalies. The quadrupole and octupole components of the CMB sky are remarkably aligned, but we find that this is not due to any single map feature; it results from the statistical combination of the full-sky anisotropy fluctuations. It may be due, in part, to chance alignments between the primary and secondary anisotropy, but this only shifts the coincidence from within the last scattering surface to between it and the local matter density distribution. While this alignment appears to be remarkable, there was no model that predicted it, nor has there been a model that provides a compelling retrodiction. We examine claims of a hemispherical or dipole power asymmetry across the sky and find that the evidence for these claims is not statistically significant. We confirm the claim of a strong quadrupolar power asymmetry effect, but there is considerable evidence that the effect is not cosmological. The likely explanation is an insufficient handling of beam asymmetries. We conclude that there is no compelling evidence for deviations from the {Lambda}CDM model, which is generally an acceptable statistical fit to WMAP and other cosmological data.
The b{tau}jEeT signal at the ongoing LHC experiments is simulated with Pythia in the minimal supergravity (mSUGRA) and other models of supersymmetry (SUSY) breaking. Special attention is given to the compatibility of this signature with the low mass neutralino dark matter (LMNDM) scenario consistent with the Wilkinson Microwave Anisotropy Probe data. In the mSUGRA model the above signal as well as the LMNDM scenario are strongly disfavored due to the constraints from the ongoing SUSY searches at the LHC. This tension, however, originates from the model dependent correlations among the parameters in the strong and electroweak sectors of mSUGRA. That there is no serious conflict between the LMNDM scenario and the LHC data is demonstrated by constructing generic phenomenological models such that the strong sector is unconstrained or mildly constrained by the existing LHC data and parameters in the electroweak sector, unrelated to the strong sector, yield dark matter relic density consistent with the Wilkinson Microwave Anisotropy Probe data. The proposed models, fairly insensitive to the conventional SUSY searches in the jets+Ee{sub T} and other channels, yield observable signal in the suggested channel for L > or approx. 1 fb{sup -1} of data. They are also consistent with the LMNDM scenario and can be tested by the direct dark matter search experiments in the near future. Some of these models can be realized by nonuniversal scalar and gaugino masses at the grand unified theory scale.
The inflationary paradigm has enjoyed phenomenological success; however, a compelling particle physics realization is still lacking. Axions are among the best-motivated inflaton candidates, since the flatness of their potential is naturally protected by a shift symmetry. We reconsider the cosmological perturbations in axion inflation, consistently accounting for the coupling to gauge fields c{phi}FF-tilde, which is generically present in these models. This coupling leads to production of gauge quanta, which provide a new source of inflaton fluctuations, {delta}{phi}. For c > or approx. 10{sup 2}M{sub p}{sup -1}, these dominate over the vacuum fluctuations, and non-Gaussianity exceeds the current observational bound. This regime is typical for concrete realizations that admit a UV completion; hence, large non-Gaussianity is easily obtained in minimal and natural realizations of inflation.
The scalar productions in heavy meson decays can provide a good platform to study not only heavy flavor physics but also their own physical properties in a dramatically different way. In this work, based on the assumption of two-quark structure of the scalars, the charmless hadronic B{sub c}{yields}SP,SV decays (here, S, P, and V denote the light scalar, pseudoscalar, and vector mesons, respectively) are investigated by employing the perturbative QCD (pQCD) factorization approach. In the standard model all these considered B{sub c} meson decays can only occur through the annihilation diagrams. From our numerical evaluations and phenomenological analysis, we find that (a) the pQCD predictions for the CP-averaged branching ratios (BRs) of the considered B{sub c} decays vary in the range of 10{sup -5} to 10{sup -8}, which will be tested in the ongoing LHCb and forthcoming Super-B experiments, while the CP-violating asymmetries for these modes are absent naturally in the standard model because only one type tree operator is involved; (b) for B{sub c}{yields}SP,SV decays, the BRs of {Delta}S=0 processes are basically much larger than those of {Delta}S=1 as generally expected because the different Cabibbo-Kobayashi-Maskawa factors are involved; (c) analogous to B{yields}K{sup *{eta}(')} decays, Br(B{sub c}{yields}{kappa}{sup +}{eta}){approx}5xBr(B{sub c}{yields}{kappa}{sup +}{eta}') in the pQCD approach, which can be understood by the constructive and destructive interference between the {eta}{sub q} and {eta}{sub s} contributions to the B{sub c}{yields}{kappa}{sup +}{eta} and B{sub c}{yields}{kappa}{sup +}{eta}' decays, however, Br(B{sub c}{yields}K{sub 0}{sup *}(1430){eta}) is approximately equal to Br(B{sub c}{yields}K{sub 0}{sup *}(1430){eta}{sup '}) in both scenarios because the factorizable contributions from the {eta}{sub s} term play the dominant role in the considered two channels; (d) if a{sub 0}(980) and {kappa} are the qq bound states, the pQCD predicted BRs for B{sub c}{yields}a{sub 0}(980)({pi},{rho}) and B{sub c}{yields}{kappa}K{sup (*)} decays will be in the range of 10{sup -6{approx}}10{sup -5}, which are within the reach of the LHCb experiments and could be measured in the near future; and (e) for the a{sub 0}(1450) and K{sub 0}{sup *}(1430) channels, the BRs for B{sub c}{yields}a{sub 0}(1450)({pi},{rho}) and B{sub c}{yields}K{sub 0}{sup *}(1430)K{sup (*)} modes in the pQCD approach are found to be (5{approx}47)x10{sup -6} and (0.7-36)x10{sup -6}, respectively. A measurement of them at the predicted level will favor the qq structure and help understand the physical properties of the scalars and the involved QCD dynamics in the modes, especially the reliability of the pQCD approach to these B{sub c} meson decays.
The recent Belle and BABAR measurements of the branching ratio of B{sup +{yields}{tau}+{nu}}{sub {tau}} indicate a significant deviation from the standard model prediction. We demonstrate that this measurement has a serious impact on models with minimal flavor violation involving a charged Higgs boson, ruling out a large portion of the currently allowed parameter space. In the constrained minimal supersymmetric standard model, this creates a tension between the measurements of B{sup +{yields}{tau}+{nu}}{sub {tau}} and the anomalous magnetic moment of the muon, unless tan{beta} is small, {mu}>0, and A{sub 0} takes a large negative value. In fact, a very small region of the parameter space of this model, with small values of m{sub 0} and m{sub 1/2}, survives all the constraints at 95% C.L. It is remarkable that this specific region is still consistent with the lightest supersymmetric particle as the dark matter. Moreover, it predicts observable supersymmetric signals in the early runs of the LHC, even perhaps at 7 TeV. We also show that a consistent explanation for the deviation of the B{sup +{yields}{tau}+{nu}}{sub {tau}} branching ratio from the standard model can be achieved in a nonuniversal Higgs-mass model, which could also predict early signals of supersymmetry at the LHC.
We consider a string-inspired nonsupersymmetric extension of the standard model with gauged anomalous U(1) flavor symmetries. Consistency requires the Green-Schwarz (GS) mechanism to cancel mixed anomalies. The additional required scalars provide Stueckelberg masses for the Z{sup '} particles associated to the gauged flavor symmetry, so they decouple at low energies. Our models also include a complex scalar field {phi} to generate Froggatt-Nielsen mass terms for light particles, giving a partial solution to the fermion mass problem. A residual approximate (anomalous) global symmetry survives at low energies. The associated pseudo-Goldstone mode is the phase of the {phi} scalar field, and it becomes the dominant contribution to the physical axion. An effective field theory analysis that includes neutrino masses gives a prediction for the axion decay constant. We find a simple model where the axion decay constant is in the center of the allowed window.
The generation of lepton asymmetry below the electroweak scale has a considerable impact on production of dark matter sterile neutrinos. Oscillations or decays of the heavier sterile neutrinos in the neutrino minimal standard model can give rise to the requisite lepton asymmetry, provided the masses of the heavier neutrinos are sufficiently degenerate. We study the renormalization group evolution of the mass difference of these singlet fermions to understand the degree of necessary fine-tuning. We construct an example of the model that can lead to a technically natural realization of this low-energy degeneracy.
We study the possibility of the existence of extra fermion families and an extra Higgs doublet. We find that requiring the extra Higgs doublet to be inert leaves space for three extra families, allowing for mirror fermion families and a dark matter candidate at the same time. The emerging scenario is very predictive: It consists of a standard model Higgs boson, with a mass above 400 GeV, heavy new quarks between 340 and 500 GeV, light extra neutral leptons, and an inert scalar with a mass below M{sub Z}.
We have derived the unitarity bounds in the high energy limit for the minimal B-L extension of the standard model by analyzing the full class of Higgs and would-be Goldstone boson two-to-two scatterings at tree level. Moreover, we have investigated how these limits could vary at some lower critical value of the energy.