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Sample records for nonperturbative running coupling

  1. AdS/QCD, LIight-Front Holography, and the Non-perturbative Running Coupling

    SciTech Connect

    Brodsky, Stanley J.; de Teramond, Guy; Deur, Alexandre; /Jefferson Lab

    2010-04-29

    The combination of Anti-de Sitter space (AdS) methods with light-front (LF) holography provides a remarkably accurate first approximation for the spectra and wavefunctions of meson and baryon light-quark bound states. The resulting bound-state Hamiltonian equation of motion in QCD leads to relativistic light-front wave equations in terms of an invariant impact variable {zeta} which measures the separation of the quark and gluonic constituents within the hadron at equal light-front time. These equations of motion in physical space-time are equivalent to the equations of motion which describe the propagation of spin-J modes in anti-de Sitter (AdS) space. The eigenvalues give the hadronic spectrum, and the eigenmodes represent the probability distributions of the hadronic constituents at a given scale. A positive-sign confining dilaton background modifying AdS space gives a very good account of meson and baryon spectroscopy and form factors. The light-front holographic mapping of this model also leads to a non-perturbative effective coupling {alpha}{sub s}{sup Ads} (Q{sup 2}) which agrees with the effective charge defined by the Bjorken sum rule and lattice simulations. It displays a transition from perturbative to nonperturbative conformal regimes at a momentum scale {approx} 1 GeV. The resulting {beta}-function appears to capture the essential characteristics of the full {beta}-function of QCD, thus giving further support to the application of the gauge/gravity duality to the confining dynamics of strongly coupled QCD.

  2. The QCD running coupling

    NASA Astrophysics Data System (ADS)

    Deur, Alexandre; Brodsky, Stanley J.; de Téramond, Guy F.

    2016-09-01

    We review the present theoretical and empirical knowledge for αs, the fundamental coupling underlying the interactions of quarks and gluons in Quantum Chromodynamics (QCD). The dependence of αs(Q2) on momentum transfer Q encodes the underlying dynamics of hadron physics-from color confinement in the infrared domain to asymptotic freedom at short distances. We review constraints on αs(Q2) at high Q2, as predicted by perturbative QCD, and its analytic behavior at small Q2, based on models of nonperturbative dynamics. In the introductory part of this review, we explain the phenomenological meaning of the coupling, the reason for its running, and the challenges facing a complete understanding of its analytic behavior in the infrared domain. In the second, more technical, part of the review, we discuss the behavior of αs(Q2) in the high momentum transfer domain of QCD. We review how αs is defined, including its renormalization scheme dependence, the definition of its renormalization scale, the utility of effective charges, as well as "Commensurate Scale Relations" which connect the various definitions of the QCD coupling without renormalization-scale ambiguity. We also report recent significant measurements and advanced theoretical analyses which have led to precise QCD predictions at high energy. As an example of an important optimization procedure, we discuss the "Principle of Maximum Conformality", which enhances QCD's predictive power by removing the dependence of the predictions for physical observables on the choice of theoretical conventions such as the renormalization scheme. In the last part of the review, we discuss the challenge of understanding the analytic behavior αs(Q2) in the low momentum transfer domain. We survey various theoretical models for the nonperturbative strongly coupled regime, such as the light-front holographic approach to QCD. This new framework predicts the form of the quark-confinement potential underlying hadron spectroscopy and

  3. The QCD running coupling

    DOE PAGES

    Deur, Alexandre; Brodsky, Stanley J.; de Téramond, Guy F.

    2016-05-09

    Here, we review present knowledge onmore » $$\\alpha_{s}$$, the Quantum Chromodynamics (QCD) running coupling. The dependence of $$\\alpha_s(Q^2)$$ on momentum transfer $Q$ encodes the underlying dynamics of hadron physics --from color confinement in the infrared domain to asymptotic freedom at short distances. We will survey our present theoretical and empirical knowledge of $$\\alpha_s(Q^2)$$, including constraints at high $Q^2$ predicted by perturbative QCD, and constraints at small $Q^2$ based on models of nonperturbative dynamics. In the first, introductory, part of this review, we explain the phenomenological meaning of the coupling, the reason for its running, and the challenges facing a complete understanding of its analytic behavior in the infrared domain. In the second, more technical, part of the review, we discuss $$\\alpha_s(Q^2)$$ in the high momentum transfer domain of QCD. We review how $$\\alpha_s$$ is defined, including its renormalization scheme dependence, the definition of its renormalization scale, the utility of effective charges, as well as `` Commensurate Scale Relations" which connect the various definitions of the QCD coupling without renormalization scale ambiguity. We also report recent important experimental measurements and advanced theoretical analyses which have led to precise QCD predictions at high energy. As an example of an important optimization procedure, we discuss the ``Principle of Maximum Conformality" which enhances QCD's predictive power by removing the dependence of the predictions for physical observables on the choice of the gauge and renormalization scheme. In last part of the review, we discuss $$\\alpha_s(Q^2)$$ in the low momentum transfer domain, where there has been no consensus on how to define $$\\alpha_s(Q^2)$$ or its analytic behavior. We will discuss the various approaches used for low energy calculations. Among them, we will discuss the light-front holographic approach to QCD in the strongly coupled

  4. The QCD running coupling

    SciTech Connect

    Deur, Alexandre; Brodsky, Stanley J.; de Téramond, Guy F.

    2016-05-09

    Here, we review present knowledge on $\\alpha_{s}$, the Quantum Chromodynamics (QCD) running coupling. The dependence of $\\alpha_s(Q^2)$ on momentum transfer $Q$ encodes the underlying dynamics of hadron physics --from color confinement in the infrared domain to asymptotic freedom at short distances. We will survey our present theoretical and empirical knowledge of $\\alpha_s(Q^2)$, including constraints at high $Q^2$ predicted by perturbative QCD, and constraints at small $Q^2$ based on models of nonperturbative dynamics. In the first, introductory, part of this review, we explain the phenomenological meaning of the coupling, the reason for its running, and the challenges facing a complete understanding of its analytic behavior in the infrared domain. In the second, more technical, part of the review, we discuss $\\alpha_s(Q^2)$ in the high momentum transfer domain of QCD. We review how $\\alpha_s$ is defined, including its renormalization scheme dependence, the definition of its renormalization scale, the utility of effective charges, as well as `` Commensurate Scale Relations" which connect the various definitions of the QCD coupling without renormalization scale ambiguity. We also report recent important experimental measurements and advanced theoretical analyses which have led to precise QCD predictions at high energy. As an example of an important optimization procedure, we discuss the ``Principle of Maximum Conformality" which enhances QCD's predictive power by removing the dependence of the predictions for physical observables on the choice of the gauge and renormalization scheme. In last part of the review, we discuss $\\alpha_s(Q^2)$ in the low momentum transfer domain, where there has been no consensus on how to define $\\alpha_s(Q^2)$ or its analytic behavior. We will discuss the various approaches used for low energy calculations. Among them, we will discuss the light-front holographic approach to QCD in the strongly coupled regime and its prediction

  5. The QCD running coupling

    SciTech Connect

    Deur, Alexandre; Brodsky, Stanley J.; de Téramond, Guy F.

    2016-05-09

    Here, we review present knowledge on $\\alpha_{s}$, the Quantum Chromodynamics (QCD) running coupling. The dependence of $\\alpha_s(Q^2)$ on momentum transfer $Q$ encodes the underlying dynamics of hadron physics --from color confinement in the infrared domain to asymptotic freedom at short distances. We will survey our present theoretical and empirical knowledge of $\\alpha_s(Q^2)$, including constraints at high $Q^2$ predicted by perturbative QCD, and constraints at small $Q^2$ based on models of nonperturbative dynamics. In the first, introductory, part of this review, we explain the phenomenological meaning of the coupling, the reason for its running, and the challenges facing a complete understanding of its analytic behavior in the infrared domain. In the second, more technical, part of the review, we discuss $\\alpha_s(Q^2)$ in the high momentum transfer domain of QCD. We review how $\\alpha_s$ is defined, including its renormalization scheme dependence, the definition of its renormalization scale, the utility of effective charges, as well as `` Commensurate Scale Relations" which connect the various definitions of the QCD coupling without renormalization scale ambiguity. We also report recent important experimental measurements and advanced theoretical analyses which have led to precise QCD predictions at high energy. As an example of an important optimization procedure, we discuss the ``Principle of Maximum Conformality" which enhances QCD's predictive power by removing the dependence of the predictions for physical observables on the choice of the gauge and renormalization scheme. In last part of the review, we discuss $\\alpha_s(Q^2)$ in the low momentum transfer domain, where there has been no consensus on how to define $\\alpha_s(Q^2)$ or its analytic behavior. We will discuss the various approaches used for low energy calculations. Among them, we will discuss the light-front holographic approach to QCD in the strongly coupled regime and its prediction

  6. QCD Coupling from a Nonperturbative Determination of the Three-Flavor Λ Parameter.

    PubMed

    Bruno, Mattia; Brida, Mattia Dalla; Fritzsch, Patrick; Korzec, Tomasz; Ramos, Alberto; Schaefer, Stefan; Simma, Hubert; Sint, Stefan; Sommer, Rainer

    2017-09-08

    We present a lattice determination of the Λ parameter in three-flavor QCD and the strong coupling at the Z pole mass. Computing the nonperturbative running of the coupling in the range from 0.2 to 70 GeV, and using experimental input values for the masses and decay constants of the pion and the kaon, we obtain Λ_{MS[over ¯]}^{(3)}=341(12)  MeV. The nonperturbative running up to very high energies guarantees that systematic effects associated with perturbation theory are well under control. Using the four-loop prediction for Λ_{MS[over ¯]}^{(5)}/Λ_{MS[over ¯]}^{(3)} yields α_{MS[over ¯]}^{(5)}(m_{Z})=0.11852(84).

  7. QCD Coupling from a Nonperturbative Determination of the Three-Flavor Λ Parameter

    NASA Astrophysics Data System (ADS)

    Bruno, Mattia; Brida, Mattia Dalla; Fritzsch, Patrick; Korzec, Tomasz; Ramos, Alberto; Schaefer, Stefan; Simma, Hubert; Sint, Stefan; Sommer, Rainer; Alpha Collaboration

    2017-09-01

    We present a lattice determination of the Λ parameter in three-flavor QCD and the strong coupling at the Z pole mass. Computing the nonperturbative running of the coupling in the range from 0.2 to 70 GeV, and using experimental input values for the masses and decay constants of the pion and the kaon, we obtain ΛMS¯ (3 )=341 (12 ) MeV . The nonperturbative running up to very high energies guarantees that systematic effects associated with perturbation theory are well under control. Using the four-loop prediction for ΛMS¯ (5 )/ΛMS¯ (3 ) yields αMS¯ (5 )(mZ)=0.11852 (84 ) .

  8. A nonperturbative light-front coupled-cluster method

    NASA Astrophysics Data System (ADS)

    Hiller, J. R.

    2012-10-01

    The nonperturbative Hamiltonian eigenvalue problem for bound states of a quantum field theory is formulated in terms of Dirac's light-front coordinates and then approximated by the exponential-operator technique of the many-body coupled-cluster method. This approximation eliminates any need for the usual approximation of Fock-space truncation. Instead, the exponentiated operator is truncated, and the terms retained are determined by a set of nonlinear integral equations. These equations are solved simultaneously with an effective eigenvalue problem in the valence sector, where the number of constituents is small. Matrix elements can be calculated, with extensions of techniques from standard coupled-cluster theory, to obtain form factors and other observables.

  9. Nonperturbative Quark Mass and Coupling Renormalization in Two Flavor QCD

    NASA Astrophysics Data System (ADS)

    Blum, Thomas Charles

    1995-01-01

    Nonperturbative bare quark mass and coupling renormalization is studied for two flavor quantum chromodynamics (QCD). In particular, the beta function for the case of Kogut-Susskind quarks is determined over the parameter space of existing lattice (spectrum) simulations from the existing spectrum data. This beta function is combined with a series of finite temperature lattice simulations (N_{t} = 4 ) to calculate the interaction measure, varepsilon-3p, which together with the pressure yields the thermal equation of state. A method of computing the asymmetry, or Karsch, coefficients, is also given. These coefficients give the parameter renormalizations for anisotropic lattices. However, for the three points in parameter space that we studied (one using Wilson fermions and two using Kogut-Susskind fermions), a clear determination of the asymmetry coefficients could not be made because of the remarkable fact that ratios of masses measured in different directions on lattices with anisotropic couplings were Euclidean invariant.

  10. Non-perturbative running of renormalization constants from correlators in coordinate space using step scaling

    NASA Astrophysics Data System (ADS)

    Cichy, Krzysztof; Jansen, Karl; Korcyl, Piotr

    2016-12-01

    Working in a quenched setup with Wilson twisted mass valence fermions, we explore the possibility to compute non-perturbatively the step scaling function using the coordinate (X-space) renormalization scheme. This scheme has the advantage of being on-shell and gauge invariant. The step scaling method allows us to calculate the running of the renormalization constants of quark bilinear operators. We describe here the details of this calculation. The aim of this exploratory study is to identify the feasibility of the X-space scheme when used in small volume simulations required by the step scaling technique. Eventually, we translate our final results to the continuum MS ‾ scheme and compare against four-loop analytic formulae finding satisfactory agreement.

  11. Nonperturbative QCD Coupling and its $\\beta$-function from Light-Front Holography

    SciTech Connect

    Brodskey, Stanley J.; de Teramond, Guy; Deur, Alexandre P.

    2010-05-28

    The light-front holographic mapping of classical gravity in AdS space, modified by a positive-sign dilaton background, leads to a non-perturbative effective coupling $\\alpha_s^{AdS}(Q^2)$. It agrees with hadron physics data extracted from different observables, such as the effective charge defined by the Bjorken sum rule, as well as with the predictions of models with built-in confinement and lattice simulations. It also displays a transition from perturbative to nonperturbative conformal regimes at a momentum scale $ \\sim 1$ GeV. The resulting $\\beta$-function appears to capture the essential characteristics of the full $\\beta$-function of QCD, thus giving further support to the application of the gauge/gravity duality to the confining dynamics of strongly coupled QCD. Commensurate scale relations relate observables to each other without scheme or scale ambiguity. In this paper we extrapolate these relations to the nonperturbative domain, thus extending the range of predictions based on $\\alpha_s^{AdS}(Q^2)$.

  12. Non-Perturbative QCD Coupling and Beta Function from Light Front Holography

    SciTech Connect

    Brodsky, Stanley J.; de Teramond, Guy F.; Deur, Alexandre; /Jefferson Lab

    2010-05-26

    The light-front holographic mapping of classical gravity in AdS space, modified by a positive-sign dilaton background, leads to a non-perturbative effective coupling {alpha}{sub s}{sup AdS} (Q{sup 2}). It agrees with hadron physics data extracted from different observables, such as the effective charge defined by the Bjorken sum rule, as well as with the predictions of models with built-in confinement and lattice simulations. It also displays a transition from perturbative to nonperturbative conformal regimes at a momentum scale {approx} 1 GeV. The resulting {beta}-function appears to capture the essential characteristics of the full {beta}-function of QCD, thus giving further support to the application of the gauge/gravity duality to the confining dynamics of strongly coupled QCD. Commensurate scale relations relate observables to each other without scheme or scale ambiguity. In this paper we extrapolate these relations to the nonperturbative domain, thus extending the range of predictions based on {alpha}{sub s}{sup AdS} (Q{sup 2}).

  13. Nonperturbative QCD coupling and its {beta} function from light-front holography

    SciTech Connect

    Brodsky, Stanley J.; Teramond, Guy F. de; Deur, Alexandre

    2010-05-01

    The light-front holographic mapping of classical gravity in anti-de Sitter space, modified by a positive-sign dilaton background, leads to a nonperturbative effective coupling {alpha}{sub s}{sup AdS}(Q{sup 2}). It agrees with hadron physics data extracted from different observables, such as the effective charge defined by the Bjorken sum rule, as well as with the predictions of models with built-in confinement and lattice simulations. It also displays a transition from perturbative to nonperturbative conformal regimes at a momentum scale {approx}1 GeV. The resulting {beta} function appears to capture the essential characteristics of the full {beta} function of QCD, thus giving further support to the application of the gauge/gravity duality to the confining dynamics of strongly coupled QCD. Commensurate scale relations relate observables to each other without scheme or scale ambiguity. In this paper we extrapolate these relations to the nonperturbative domain, thus extending the range of predictions based on {alpha}{sub s}{sup AdS}(Q{sup 2}).

  14. A light-front coupled-cluster method for the nonperturbative solution of quantum field theories

    NASA Astrophysics Data System (ADS)

    Chabysheva, Sophia S.; Hiller, John R.

    2012-05-01

    We propose a new method for the nonperturbative solution of quantum field theories and illustrate its use in the context of a light-front analog to the Greenberg-Schweber model. The method is based on light-front quantization and uses the exponential-operator technique of the many-body coupled-cluster method. The formulation produces an effective Hamiltonian eigenvalue problem in the valence Fock sector of the system of interest, combined with nonlinear integral equations to be solved for the functions that define the effective Hamiltonian. The method avoids the Fock-space truncations usually used in nonperturbative light-front Hamiltonian methods and, therefore, does not suffer from the spectator dependence, Fock-sector dependence, and uncanceled divergences caused by such truncations.

  15. Nonperturbative QCD Coupling and its $$\\beta$$-function from Light-Front Holography

    DOE PAGES

    Brodskey, Stanley J.; de Teramond, Guy; Deur, Alexandre P.

    2010-05-28

    The light-front holographic mapping of classical gravity in AdS space, modified by a positive-sign dilaton background, leads to a non-perturbative effective couplingmore » $$\\alpha_s^{AdS}(Q^2)$$. It agrees with hadron physics data extracted from different observables, such as the effective charge defined by the Bjorken sum rule, as well as with the predictions of models with built-in confinement and lattice simulations. It also displays a transition from perturbative to nonperturbative conformal regimes at a momentum scale $$ \\sim 1$$ GeV. The resulting $$\\beta$$-function appears to capture the essential characteristics of the full $$\\beta$$-function of QCD, thus giving further support to the application of the gauge/gravity duality to the confining dynamics of strongly coupled QCD. Commensurate scale relations relate observables to each other without scheme or scale ambiguity. In this paper we extrapolate these relations to the nonperturbative domain, thus extending the range of predictions based on $$\\alpha_s^{AdS}(Q^2)$$.« less

  16. Ghost-gluon running coupling, power corrections, and the determination of {lambda}{sub MS}

    SciTech Connect

    Boucaud, Ph.; Leroy, J. P.; Le Yaouanc, A.; Micheli, J.; Pene, O.; De Soto, F.; Rodriguez-Quintero, J.

    2009-01-01

    We compute a formula including operator-product expansion power corrections to describe the running of a QCD coupling nonperturbatively defined through the ghost and gluon dressing functions. This turns out to be rather accurate. We propose the 'plateau' procedure to compute {lambda}{sub MS} from the lattice computation of the running coupling constant. We show a good agreement between the different methods which have been used to estimate {lambda}{sub MS}{sup N{sub f}}{sup =0}. We argue that {lambda}{sub MS} or the strong coupling constant computed with different lattice spacings may be used to estimate the lattice spacing ratio.

  17. Gravitational correction to running of gauge couplings.

    PubMed

    Robinson, Sean P; Wilczek, Frank

    2006-06-16

    We calculate the contribution of graviton exchange to the running of gauge couplings at lowest non-trivial order in perturbation theory. Including this contribution in a theory that features coupling constant unification does not upset this unification, but rather shifts the unification scale. When extrapolated formally, the gravitational correction renders all gauge couplings asymptotically free.

  18. Ultrastrong coupling of a single artificial atom to an electromagnetic continuum in the nonperturbative regime

    NASA Astrophysics Data System (ADS)

    Forn-Díaz, P.; García-Ripoll, J. J.; Peropadre, B.; Orgiazzi, J.-L.; Yurtalan, M. A.; Belyansky, R.; Wilson, C. M.; Lupascu, A.

    2017-01-01

    The study of light-matter interaction has led to important advances in quantum optics and enabled numerous technologies. Over recent decades, progress has been made in increasing the strength of this interaction at the single-photon level. More recently, a major achievement has been the demonstration of the so-called strong coupling regime, a key advancement enabling progress in quantum information science. Here, we demonstrate light-matter interaction over an order of magnitude stronger than previously reported, reaching the nonperturbative regime of ultrastrong coupling (USC). We achieve this using a superconducting artificial atom tunably coupled to the electromagnetic continuum of a one-dimensional waveguide. For the largest coupling, the spontaneous emission rate of the atom exceeds its transition frequency. In this USC regime, the description of atom and light as distinct entities breaks down, and a new description in terms of hybrid states is required. Beyond light-matter interaction itself, the tunability of our system makes it a promising tool to study a number of important physical systems, such as the well-known spin-boson and Kondo models.

  19. BFKL equation with running QCD coupling and HERA data

    NASA Astrophysics Data System (ADS)

    Levin, Eugene; Potashnikova, Irina

    2014-02-01

    In this paper we developed approach based on the BFKL evolution in ln( Q 2). We show that the simplest diffusion approximation with running QCD coupling is able to describe the HERA experimental data on the deep inelastic structure function with good χ2 /d .o .f . ≈ 1 .3. From our description of the experimental data we learned several lessons; (i) the non-perturbative physics at long distances started to show up at Q 2 = 0 .25 GeV2; (ii) the scattering amplitude at Q 2 = 0 .25 GeV2 cannot be written as sum of soft Pomeron and the secondary Reggeon but the Pomeron interactions should be taken into account; (iii) the Pomeron interactions can be reduced to the enhanced diagrams and, therefore, we do not see any needs for the shadowing corrections at HERA energies; and (iv) we demonstrated that the shadowing correction could be sizable at higher than HERA energies without any contradiction with our initial conditions.

  20. Process-independent strong running coupling

    NASA Astrophysics Data System (ADS)

    Binosi, Daniele; Mezrag, Cédric; Papavassiliou, Joannis; Roberts, Craig D.; Rodríguez-Quintero, Jose

    2017-09-01

    We unify two widely different approaches to understanding the infrared behavior of quantum chromodynamics (QCD), one essentially phenomenological, based on data, and the other computational, realized via quantum field equations in the continuum theory. Using the latter, we explain and calculate a process-independent running coupling for QCD, a new type of effective charge that is an analogue of the Gell-Mann-Low effective coupling in quantum electrodynamics. The result is almost identical to the process-dependent effective charge defined via the Bjorken sum rule, which provides one of the most basic constraints on our knowledge of nucleon spin structure. This reveals the Bjorken sum to be a near direct means by which to gain empirical insight into QCD's Gell-Mann-Low effective charge.

  1. Slow running of the gradient flow coupling from 200 MeV to 4 GeV in Nf=3 QCD

    NASA Astrophysics Data System (ADS)

    Dalla Brida, Mattia; Fritzsch, Patrick; Korzec, Tomasz; Ramos, Alberto; Sint, Stefan; Sommer, Rainer

    2017-01-01

    Using a finite volume gradient flow renormalization scheme with Schrödinger Functional boundary conditions, we compute the nonperturbative running coupling in the range 2.2 ≲g¯GF 2(L )≲13 . Careful continuum extrapolations turn out to be crucial to reach our high accuracy. The running of the coupling is always between one loop and two loop and very close to one loop in the region of 200 MeV ≲μ =1 /L ≲4 GeV . While there is no convincing contact to two-loop running, we match nonperturbatively to the Schrödinger functional coupling with background field. In this case, we know the μ -dependence up to ˜100 GeV and can thus connect to the Λ -parameter.

  2. AdS/QCD, Light-Front Holography, and the Nonperturbative Running Coupling

    SciTech Connect

    Stanley J. Brodsky, Guy F. de Téramond, Alexandre Deur

    2010-11-01

    We have analyzed the beam spin asymmetry and the longitudinally polarized target spin asymmetry of the Deep Virtual Compton Scattering process, recently measured by the Jefferson Lab CLAS collaboration. Our aim is to extract information about the Generalized Parton Distributions of the proton. By fitting these data, in a largely model-independent procedure, we are able to extract numerical values for the two Compton Form Factors $H_{Im}$ and $\\tilde{H}_{Im}$ with uncertainties, in average, of the order of 30%.

  3. Running couplings in equivariantly gauge-fixed SU(N) Yang-Mills theories

    NASA Astrophysics Data System (ADS)

    Golterman, Maarten; Shamir, Yigal

    2006-01-01

    In equivariantly gauge-fixed SU(N) Yang-Mills theories, the gauge symmetry is only partially fixed, leaving a subgroup H⊂SU(N) unfixed. Such theories avoid Neuberger’s nogo theorem if the subgroup H contains at least the Cartan subgroup U(1)N-1, and they are thus nonperturbatively well defined if regulated on a finite lattice. We calculate the one-loop beta function for the coupling gtilde 2=ξg2, where g is the gauge coupling and ξ is the gauge parameter, for a class of subgroups including the cases that H=U(1)N-1 or H=SU(M)×SU(N-M)×U(1). The coupling gtilde represents the strength of the interaction of the gauge degrees of freedom associated with the coset SU(N)/H. We find that gtilde , like g, is asymptotically free. We solve the renormalization-group equations for the running of the couplings g and gtilde , and find that dimensional transmutation takes place also for the coupling gtilde , generating an infrared scale Λ˜ which can be larger than or equal to the scale Λ associated with the gauge coupling g, but not smaller. We speculate on the possible implications of these results.

  4. Status of Higgs couplings after run 1 of the LHC

    NASA Astrophysics Data System (ADS)

    Bernon, Jérémy; Dumont, Béranger; Kraml, Sabine

    2014-10-01

    We provide an update of the global fits of the couplings of the 125.5 GeV Higgs boson using all publicly available experimental results from run 1 of the LHC as per summer 2014. The fits are done by means of the new public code Lilith 1.0. We present a selection of results given in terms of signal strengths, reduced couplings, and for the two-Higgs-doublet models of type I and II.

  5. Intersegmental coupling and recovery from perturbations in freely running cockroaches.

    PubMed

    Couzin-Fuchs, Einat; Kiemel, Tim; Gal, Omer; Ayali, Amir; Holmes, Philip

    2015-01-15

    Cockroaches are remarkably stable runners, exhibiting rapid recovery from external perturbations. To uncover the mechanisms behind this important behavioral trait, we recorded leg kinematics of freely running animals in both undisturbed and perturbed trials. Functional coupling underlying inter-leg coordination was monitored before and during localized perturbations, which were applied to single legs via magnetic impulses. The resulting transient effects on all legs and the recovery times to normal pre-perturbation kinematics were studied. We estimated coupling architecture and strength by fitting experimental data to a six-leg-unit phase oscillator model. Using maximum-likelihood techniques, we found that a network with nearest-neighbor inter-leg coupling best fitted the data and that, although coupling strengths vary among preparations, the overall inputs entering each leg are approximately balanced and consistent. Simulations of models with different coupling strengths encountering perturbations suggest that the coupling schemes estimated from our experiments allow animals relatively fast and uniform recoveries from perturbations.

  6. Coupled-bunch instabilities of the Tevatron at Run II

    SciTech Connect

    K. Y. Ng

    2003-03-06

    The longitudinal and transverse coupled-bunch instabilities of the Tevatron at Run II are addressed in two scenarios. The first scenario corresponds to the present Run II condition: 36 proton bunches on 36 antiprotons. Each proton bunch contains 1.7 x 10{sup 11} particles with a rms bunch length 60 cm. The second scenario is for the future upgrade when there are 108 proton bunches colliding with 108 antiproton bunches. Each proton bunch contains 2.7 x 10{sup 11} particles with a rms bunch length 50 cm. The analysis shows that the growth rates of transverse coupled-bunch instabilities are slow and will be damped by a small betatron tune spread. On the other hand, growth rates of longitudinal coupled-bunch instabilities will be fast especially for the 108-by-108 scenario.

  7. Five-Loop Running of the QCD Coupling Constant.

    PubMed

    Baikov, P A; Chetyrkin, K G; Kühn, J H

    2017-02-24

    We analytically compute the five-loop term in the beta function which governs the running of α_{s}-the quark-gluon coupling constant in QCD. The new term leads to a reduction of the theory uncertainty in α_{s} taken at the Z-boson scale as extracted from the τ-lepton decays as well as to new, improved by one more order of perturbation theory, predictions for the effective coupling constants of the standard model Higgs boson to gluons and for its total decay rate to the quark-antiquark pairs.

  8. Five-Loop Running of the QCD Coupling Constant

    NASA Astrophysics Data System (ADS)

    Baikov, P. A.; Chetyrkin, K. G.; Kühn, J. H.

    2017-02-01

    We analytically compute the five-loop term in the beta function which governs the running of αs—the quark-gluon coupling constant in QCD. The new term leads to a reduction of the theory uncertainty in αs taken at the Z -boson scale as extracted from the τ -lepton decays as well as to new, improved by one more order of perturbation theory, predictions for the effective coupling constants of the standard model Higgs boson to gluons and for its total decay rate to the quark-antiquark pairs.

  9. Intersegmental coupling and recovery from perturbations in freely running cockroaches

    PubMed Central

    Couzin-Fuchs, Einat; Kiemel, Tim; Gal, Omer; Ayali, Amir; Holmes, Philip

    2015-01-01

    Cockroaches are remarkably stable runners, exhibiting rapid recovery from external perturbations. To uncover the mechanisms behind this important behavioral trait, we recorded leg kinematics of freely running animals in both undisturbed and perturbed trials. Functional coupling underlying inter-leg coordination was monitored before and during localized perturbations, which were applied to single legs via magnetic impulses. The resulting transient effects on all legs and the recovery times to normal pre-perturbation kinematics were studied. We estimated coupling architecture and strength by fitting experimental data to a six-leg-unit phase oscillator model. Using maximum-likelihood techniques, we found that a network with nearest-neighbor inter-leg coupling best fitted the data and that, although coupling strengths vary among preparations, the overall inputs entering each leg are approximately balanced and consistent. Simulations of models with different coupling strengths encountering perturbations suggest that the coupling schemes estimated from our experiments allow animals relatively fast and uniform recoveries from perturbations. PMID:25609786

  10. Nonperturbative QCD corrections to electroweak observables

    SciTech Connect

    Dru B Renner, Xu Feng, Karl Jansen, Marcus Petschlies

    2011-12-01

    Nonperturbative QCD corrections are important to many low-energy electroweak observables, for example the muon magnetic moment. However, hadronic corrections also play a significant role at much higher energies due to their impact on the running of standard model parameters, such as the electromagnetic coupling. Currently, these hadronic contributions are accounted for by a combination of experimental measurements and phenomenological modeling but ideally should be calculated from first principles. Recent developments indicate that many of the most important hadronic corrections may be feasibly calculated using lattice QCD methods. To illustrate this, we will examine the lattice computation of the leading-order QCD corrections to the muon magnetic moment, paying particular attention to a recently developed method but also reviewing the results from other calculations. We will then continue with several examples that demonstrate the potential impact of the new approach: the leading-order corrections to the electron and tau magnetic moments, the running of the electromagnetic coupling, and a class of the next-to-leading-order corrections for the muon magnetic moment. Along the way, we will mention applications to the Adler function, the determination of the strong coupling constant and QCD corrections to muonic-hydrogen.

  11. Impact of dispersed coupling strength on the free running periods of circadian rhythms

    NASA Astrophysics Data System (ADS)

    Gu, Changgui; Rohling, Jos H. T.; Liang, Xiaoming; Yang, Huijie

    2016-03-01

    The dominant endogenous clock, named the suprachiasmatic nucleus (SCN), regulates circadian rhythms of behavioral and physiological activity in mammals. One of the main characteristics of the SCN is that the animal maintains a circadian rhythm with a period close to 24 h in the absence of a daily light-dark cycle (called the free running period). The free running period varies among species due to heterogeneity of the SCN network. Previous studies have shown that the heterogeneity in cellular coupling as well as in intrinsic neuronal periods shortens the free running period. Furthermore, as derived from experiments, one neuron's coupling strength is negatively associated with its period. It is unknown what the effects of this association between coupling strength and period are on the free running period and how the heterogeneity in coupling strength influences this free running period. In the present study we found that in the presence of a negative relationship between one neuron's coupling strength and its period, surprisingly, the dispersion of coupling strengths increases the free running period. Our present finding may shed new light on the understanding of the heterogeneous SCN network and provides an alternative explanation for the diversity of free running periods between species.

  12. Asymptotics of QCD traveling waves with fluctuations and running coupling effects

    NASA Astrophysics Data System (ADS)

    Beuf, Guillaume

    2008-09-01

    Extending the Balitsky-Kovchegov (BK) equation independently to running coupling or to fluctuation effects due to pomeron loops is known to lead in both cases to qualitative changes of the traveling-wave asymptotic solutions. In this paper we study the extension of the forward BK equation, including both running coupling and fluctuations effects, extending the method developed for the fixed coupling case [E. Brunet, B. Derrida, A.H. Mueller, S. Munier, Phys. Rev. E 73 (2006) 056126, cond-mat/0512021]. We derive the exact asymptotic behavior in rapidity of the probabilistic distribution of the saturation scale.

  13. New scheme for the running coupling constant in gauge theories using Wilson loops

    SciTech Connect

    Bilgici, Erek; Flachi, Antonino; Onogi, Tetsuya; Itou, Etsuko; Kurachi, Masafumi; Lin, C.-J. David; Matsufuru, Hideo; Ohki, Hiroshi; Yamazaki, Takeshi

    2009-08-01

    We propose a new renormalization scheme of the running coupling constant in general gauge theories using the Wilson loops. The renormalized coupling constant is obtained from the Creutz ratio in lattice simulations and the corresponding perturbative coefficient at the leading order. The latter can be calculated by adopting the zeta-function resummation techniques. We perform a benchmark test of our scheme in quenched QCD with the plaquette gauge action. The running of the coupling constant is determined by applying the step-scaling procedure. Using several methods to improve the statistical accuracy, we show that the running coupling constant can be determined in a wide range of energy scales with a relatively small number of gauge configurations.

  14. A new scheme for the running coupling constant in gauge theories using Wilson loops

    SciTech Connect

    Kurachi, Masafumi; Bilgici, Erek; Flachi, Antonion; Itou, Etsuko; David Lin, C J; Matsufuru, Hideo; Ohki, Hiroshi; Onogi, Tetsuya; Yamazaki, Takeshi

    2009-01-01

    We propose a new renormalization scheme of the running coupling constant in general gauge theories defined by using the Wilson loops. The renormalized coupling constant is obtained from the Cretz ratio in lattice simulations and the corresponding perturbative coefficient at the leading order. The latter calculation is performed by adopting the zeta-function resummation techniques. We make a benchmark test of our scheme in quenched QCD with the plaquette gauge action. The running of the coupling constant is determined by applying the step scaling procedure. Using several methods to improve the statistical accuracy, we show that the running coupling constant can be determined in a wide range of energy scales with relatively small number of gauge configurations.

  15. Perturbative and nonperturbative aspects of jet quenching in near-critical quark-gluon plasmas

    NASA Astrophysics Data System (ADS)

    Xu, Jiechen

    In this thesis, we construct two QCD based energy loss models to perform quantitative analysis of jet quenching observables in ultra-relativistic nucleus-nucleus collisions at RHIC and the LHC. We first build up a perturbative QCD based CUJET2.0 jet flavor tomography model that couples the dynamical running coupling DGLV opacity series to bulk data constrained relativistic viscous hydrodynamic backgrounds. It solves the strong heavy quark energy loss puzzle at RHIC and explains the surprising transparency of the quark-gluon plasma (QGP) at the LHC. The observed azimuthal anisotropy of hard leading hadrons requires a path dependent jet-medium coupling in CUJET2.0 that implies physics of nonperturbative origin. To explore the nonperturbative chromo-electric and chromo-magnetic structure of the strongly-coupled QGP through jet probes, we build up a new CUJET3.0 framework that includes in CUJET2.0 both Polyakov loop suppressed semi-QGP chromo-electric charges and emergent chromo-magnetic monopoles in the critical transition regime. CUJET3.0 quantitatively describes the anisotropic hadron suppression at RHIC and the LHC. More significantly, it provides a robust connection between the long wavelength ``perfect fluidity'' of the QGP and the short distance jet transport in the QGP. This framework paves the way for ``measuring'' both perturbative and nonperturbative properties of the QGP, and more importantly for probing color confinement through jet quenching.

  16. Infrared Fixed Point in the Strong Running Coupling: Unraveling the ΔI = 1/2 Puzzle in K-Decays

    NASA Astrophysics Data System (ADS)

    Crewther, R. J.; Tunstall, Lewis C.

    2013-08-01

    In this paper, we present an explanation for the ΔI = 1/2 rule in K-decays based on the premise of an infrared fixed point αIR in the running coupling αs of quantum chromodynamics (QCD) for three light quarks u, d, s. At the fixed point, the quark condensate <\\bar {q}q> vac !=q 0 spontaneously breaks scale and chiral SU(3)L×SU(3)R symmetry. Consequently, the low-lying spectrum contains nine Nambu-Goldstone bosons: π, K, η and a QCD dilaton σ. We identify σ as the f0(500) resonance and construct a chiral-scale perturbation theory χPTσ for low-energy amplitudes expanded in αs about αIR. The ΔI = 1/2 rule emerges in the leading order of χPTσ through a σ-pole term KS→σ→ππ, with a gKSσ coupling fixed by data on γγ→π0π0 and KS→γγ. We also determine RIR ≈5 for the nonperturbative Drell-Yan ratio at αIR.

  17. PROGRESS IN TUNE, COUPLING, AND CHROMATICITY MEASUREMENT AND FEEDBACK DURING RHIC RUN 7

    SciTech Connect

    CAMERON,P.; DELLAPENNA, A.; HOFF, L.; LUO, Y.; MARUSIC, A.; SCHULTHEISS, C.; TEPIKIAN, S.; ET AL.

    2007-06-25

    Tune feedback was first implemented in RHIC in 2002, as a specialist activity. The transition of the tune feedback system to full operational status was impeded by dynamic range problems, as well as by overall loop instabilities driven by large coupling. The dynamic range problem was solved by the CERN development of the Direct Diode Detection Analog Front End. Continuous measurement of all projections of the betatron eigenmodes made possible the world's first implementation of coupling feedback during beam acceleration, resolving the problem of overall loop instabilities. Simultaneous tune and coupling feedbacks were utilized as specialist activities for ramp development during the 2006 RHIC run. At the beginning of the 2007 RHIC run there remained two obstacles to making these feedbacks fully operational in RHIC - chromaticity measurement and control, and the presence of strong harmonics of the power line frequency in the betatron spectrum. We report on progress in tune, coupling, and chromaticity measurement and feedback, and discuss the relevance of our results to LHC commissioning.

  18. Gradient flow running coupling in SU(2) gauge theory with Nf=8 fundamental flavors

    NASA Astrophysics Data System (ADS)

    Leino, Viljami; Rantaharju, Jarno; Rantalaiho, Teemu; Rummukainen, Kari; Suorsa, Joni; Tuominen, Kimmo

    2017-06-01

    We study the evolution of the coupling in SU(2) gauge field theory with Nf=8 fundamental fermion flavors on the lattice. This model is expected to have an infrared fixed point at high coupling. We use HEX-smeared Wilson-clover action, and measure the gradient flow running coupling with Dirichlet boundary conditions. Extrapolating our results to continuum, we find an infrared fixed point at g*2=8.24 (59 )-1.64+0.97 , with statistical and systematic error estimates. We also measure the anomalous dimension of the quark mass operator, and find its value at the fixed point γ*≃0.15 ±0.02 , although for this quantity a reliable continuum limit is still lacking.

  19. Entanglement in quantum impurity problems is nonperturbative

    NASA Astrophysics Data System (ADS)

    Saleur, H.; Schmitteckert, P.; Vasseur, R.

    2013-08-01

    We study the entanglement entropy of a region of length 2L with the remainder of an infinite one-dimensional gapless quantum system in the case where the region is centered on a quantum impurity. The coupling to this impurity is not scale invariant, and the physics involves a crossover between weak- and strong-coupling regimes. While the impurity contribution to the entanglement has been computed numerically in the past, little is known analytically about it, since in particular the methods of conformal invariance cannot be applied because of the presence of a crossover length. We show in this paper that the small coupling expansion of the entanglement entropy in this problem is quite generally plagued by strong infrared divergences, implying a nonperturbative dependence on the coupling. The large coupling expansion turns out to be better behaved, thanks to powerful results from the boundary CFT formulation and, in some cases, the underlying integrability of the problem. However, it is clear that this expansion does not capture well the crossover physics. In the integrable case—which includes problems such as an XXZ chain with a modified link, the interacting resonant level model or the anisotropic Kondo model—a nonperturbative approach is in principle possible using form factors. We adapt in this paper the ideas of Cardy [J. Stat. Phys.JSTPBS0022-471510.1007/s10955-007-9422-x 130, 129 (2008)] and Castro-Alvaredo and Doyon [J. Stat. Phys.JSTPBS0022-471510.1007/s10955-008-9664-2 134, 105 (2009)] to the gapless case and show that, in the rather simple case of the resonant level model, and after some additional renormalizations, the form-factors approach yields remarkably accurate results for the entanglement all the way from short to large distances. This is confirmed by detailed comparison with numerical simulations. Both our form factor and numerical results are compatible with a nonperturbative form at short distance.

  20. Supersymmetry and supergravity nonperturbative OCD

    SciTech Connect

    Roy, P.; Singh, V.

    1984-01-01

    This book contains 13 selections. Some of the titles are: Introduction to global supersymmetry; TeV scale models with two supersymmetries; Anomalies and index theory; and Methods in non-perturbative field theory.

  1. On the interface between perturbative and nonperturbative QCD

    DOE PAGES

    Deur, Alexandre; Brodsky, Stanley J.; de Teramond, Guy F.

    2016-04-04

    The QCD running coupling αs(Q2) sets the strength of the interactions of quarks and gluons as a function of the momentum transfer Q . The Q2 dependence of the coupling is required to describe hadronic interactions at both large and short distances. In this article we adopt the light-front holographic approach to strongly-coupled QCD, a formalism which incorporates confinement, predicts the spectroscopy of hadrons composed of light quarks, and describes the low- Q2 analytic behavior of the strong coupling αs(Q2) . The high- Q2 dependence of the coupling αs(Q2) is specified by perturbative QCD and its renormalization group equation. Themore » matching of the high and low Q2 regimes of αs(Q2) then determines the scale Q0 which sets the interface between perturbative and nonperturbative hadron dynamics. The value of Q0 can be used to set the factorization scale for DGLAP evolution of hadronic structure functions and the ERBL evolution of distribution amplitudes. We discuss the scheme-dependence of the value of Q0 and the infrared fixed-point of the QCD coupling. Our analysis is carried out for the MS¯, g1, MOM and V renormalization schemes. Our results show that the discrepancies on the value of αs at large distance seen in the literature can be explained by different choices of renormalization schemes. Furthermore, we also provide the formulae to compute αs(Q2) over the entire range of space-like momentum transfer for the different renormalization schemes discussed in this article.« less

  2. On the interface between perturbative and nonperturbative QCD

    NASA Astrophysics Data System (ADS)

    Deur, Alexandre; Brodsky, Stanley J.; de Téramond, Guy F.

    2016-06-01

    The QCD running coupling αs (Q2) sets the strength of the interactions of quarks and gluons as a function of the momentum transfer Q. The Q2 dependence of the coupling is required to describe hadronic interactions at both large and short distances. In this article we adopt the light-front holographic approach to strongly-coupled QCD, a formalism which incorporates confinement, predicts the spectroscopy of hadrons composed of light quarks, and describes the low-Q2 analytic behavior of the strong coupling αs (Q2). The high-Q2 dependence of the coupling αs (Q2) is specified by perturbative QCD and its renormalization group equation. The matching of the high and low Q2 regimes of αs (Q2) then determines the scale Q0 which sets the interface between perturbative and nonperturbative hadron dynamics. The value of Q0 can be used to set the factorization scale for DGLAP evolution of hadronic structure functions and the ERBL evolution of distribution amplitudes. We discuss the scheme-dependence of the value of Q0 and the infrared fixed-point of the QCD coupling. Our analysis is carried out for the MS ‾, g1, MOM and V renormalization schemes. Our results show that the discrepancies on the value of αs at large distance seen in the literature can be explained by different choices of renormalization schemes. We also provide the formulae to compute αs (Q2) over the entire range of space-like momentum transfer for the different renormalization schemes discussed in this article.

  3. On the interface between perturbative and nonperturbative QCD

    SciTech Connect

    Deur, Alexandre; Brodsky, Stanley J.; de Téramond, Guy F.

    2016-06-01

    The QCD running coupling αs(Q2) sets the strength of the interactions of quarks and gluons as a function of the momentum transfer Q . The Q2 dependence of the coupling is required to describe hadronic interactions at both large and short distances. In this article we adopt the light-front holographic approach to strongly-coupled QCD, a formalism which incorporates confinement, predicts the spectroscopy of hadrons composed of light quarks, and describes the low-Q2 analytic behavior of the strong coupling αs(Q2). The high-Q2 dependence of the coupling αs(Q2) is specified by perturbative QCD and its renormalization group equation. The matching of the high and low Q2 regimes of αs(Q2) then determines the scale Q0 which sets the interface between perturbative and nonperturbative hadron dynamics. The value of Q0 can be used to set the factorization scale for DGLAP evolution of hadronic structure functions and the ERBL evolution of distribution amplitudes. We discuss the scheme-dependence of the value of Q0 and the infrared fixed-point of the QCD coupling. Our analysis is carried out for the View the MathML source, g1, MOM and V renormalization schemes. Our results show that the discrepancies on the value of αs at large distance seen in the literature can be explained by different choices of renormalization schemes. We also provide the formulae to compute αs(Q2) over the entire range of space-like momentum transfer for the different renormalization schemes discussed in this article.

  4. Dynamic Hydrological Discharge Modelling for Fully Coupled Paleoclimate Runs of the Last Glacial Cycle

    NASA Astrophysics Data System (ADS)

    Riddick, Thomas; Brovkin, Victor; Hagemann, Stefan; Mikolajewicz, Uwe

    2017-04-01

    The continually evolving large ice sheets present in the Northern Hemisphere during the last glacial cycle caused significant changes to river pathways both through directly blocking rivers and through glacial isostatic adjustment. These river pathway changes are believed to of had a significant impact on the evolution of ocean circulation through changing the pattern of fresh water discharge into the oceans. A fully coupled ESM simulation of the last glacial cycle thus requires a hydrological discharge model that uses a set of river pathways that evolve with the earth's changing orography while being able to reproduce the known present-day river network given the present-day orography. Here we present a method for dynamically modelling hydrological discharge that meets such requirements by applying relative manual corrections to an evolving fine scale orography (accounting for the changing ice sheets and isostatic rebound) each time the river directions are recalculated. The corrected orography thus produced is then used to create a set of fine scale river pathways and these are then upscaled to a course scale. An existing present-day hydrological discharge model within the JSBACH3 land surface model is run using the course scale river pathways generated. This method will be used in fully coupled paleoclimate runs made using MPI-ESM1 as part of the PalMod project. Tests show this procedure reproduces the known present-day river network to a sufficient degree of accuracy.

  5. The non-perturbative unquenched quark model

    NASA Astrophysics Data System (ADS)

    Entern, D. R.; Ortega, P. G.; Fernández, F.

    2017-03-01

    In recent years states in the quarkonium spectrum not expected in the naive quark model have appeared and created a lot of interest. In the theoretical side the study of the effect of meson-meson thresholds in the spectrum have been performed in different approximations. In a quark model framework, and in the spirit of the Cornell model, when a meson-meson threshold is included, the coupling to all the quark-antiquark states have to be considered. In practice only the closest states are included perturbatively. In this contribution we will present a framework in which we couple quark-antiquark states with meson-meson states non-perturbatively, taking into account effectively the coupling to all quark-antiquark states. The method will be applied to the study of the X(3872) and a comparison with the perturbative calculation will be performed.

  6. Stable strange quark matter objects with running masses and coupling constant

    NASA Astrophysics Data System (ADS)

    Xia, Cheng-Jun; Zhou, Shan-Gui

    2017-03-01

    We improve our recently proposed unified description for strange quark matter (SQM) objects, in the way that analytical expressions are derived and used to calculate the distribution of particles inside an SQM object. In the improved model, the computational time is greatly reduced without losing accuracy. The properties of SQM objects are then investigated by adopting perturbative quantum chromodynamics (pQCD) with running quark masses and coupling constant. Aside from the increase of masses and radii of strange stars, it is found that the perturbative interactions also make the electric field on the surface stronger and extends deeper into the core, while small SQM objects become less compact and more positively charged. These may affect the experimental searches of SQM.

  7. Dynamics and thermodynamics of a nonlocal Polyakov--Nambu--Jona-Lasinio model with running coupling

    SciTech Connect

    Hell, T.; Roessner, S.; Cristoforetti, M.; Weise, W.

    2009-01-01

    A nonlocal covariant extension of the two-flavor Nambu and Jona-Lasinio model is constructed, with built-in constraints from the running coupling of QCD at high-momentum and instanton physics at low-momentum scales. Chiral low-energy theorems and basic current algebra relations involving pion properties are shown to be reproduced. The momentum-dependent dynamical quark mass derived from this approach is in agreement with results from Dyson-Schwinger equations and lattice QCD. At finite temperature, inclusion of the Polyakov loop and its gauge invariant coupling to quarks reproduces the dynamical entanglement of the chiral and deconfinement crossover transitions as in the (local) Polyakov-loop-extended Nambu and Jona-Lasinio model, but now without the requirement of introducing an artificial momentum cutoff. Steps beyond the mean-field approximation are made including mesonic correlations through quark-antiquark ring summations. Various quantities of interest (pressure, energy density, speed of sound, etc.) are calculated and discussed in comparison with lattice QCD thermodynamics at zero chemical potential. The extension to finite quark chemical potential and the phase diagram in the (T,{mu})-plane are also discussed.

  8. Developing a run-time coupling between ESP-r and TRNSYS

    NASA Astrophysics Data System (ADS)

    Jost, Romain

    Rigorous modeling is essential to design buildings and deliver the next advances in energy efficiency and on-site renewable energy production. A great variety of energy simulation programs exists but they are, for the most part, specialized in one particular domain and they do not allow a complete analysis. Because all domains (heating, cooling, ventilation, lighting, acoustic) are interconnected and there is no global simulation environment existing that covers all of the system particularities with the same flexibility, it is often appropriate to proceed with software combination and/or coupling. This Master thesis describes the implementation of a run-time coupling between TRNSYS and ESP-r. In order to minimize the modifications to the source codes and create a tool able to support future development of each program, new components that receive and pass data to the other program were implemented in the two software programs. A multi DLL structure enables the coupling and exchange of information. A third piece of software, the Harmonizer, launches TRNSYS and ESP-r DLLS and manages the exchange of data. It is also responsible of the convergence handling and controls that both programs march through time together time step after time step. A new category of components, the Data Exchanger Types was implemented in TRNSYS. These components can work as standard TRNSYS Types and exchange data through their inputs and outputs but they can also impose the solver to continue iterating. This capability is essential to force TRNSYS to do more calculations at a specific time step when it has converged but co-simulation convergence requires more iterations. A component of this new category, Type 130, was created specifically for the coupling with ESP-r. Type 130 exchanges data with the Harmonizer on one side and with the TRNSYS network of Types on the other side. Testing of basic data exchange validates the data exchange method and the coupling. The co-simulator is able to

  9. Horizon Run 4 Simulation: Coupled Evolution of Galaxies and Large-Scale Structures of the Universe

    NASA Astrophysics Data System (ADS)

    Kim, Juhan; Park, Changbom; L'Huillier, Benjamin; Hong, Sungwook E.

    2015-08-01

    The Horizon Run 4 is a cosmological N-body simulation designed for the study of coupled evolution between galaxies and large-scale structures of the Universe, and for the test of galaxy formation models. Using 6300^3 gravitating particles in a cubic box of L_{box} = 3150 h^{-1} Mpc, we build a dense forest of halo merger trees to trace the halo merger history with a halo mass resolution scale down to M_s = 2.7 × 10^{11} h^{-1} M_⊙. We build a set of particle and halo data, which can serve as testbeds for comparison of cosmological models and gravitational theories with observations. We find that the FoF halo mass function shows a substantial deviation from the universal form with tangible redshift evolution of amplitude and shape. At higher redshifts, the amplitude of the mass function is lower, and the functional form is shifted toward larger values of ln (1/σ). We also find that the baryonic acoustic oscillation feature in the two-point correlation funct-ion of mock galaxies becomes broader with a peak position moving to smaller scales and the peak amplitude decreasing for increasing directional cosine mu compared to the linear predictions. From the halo merger trees built from halo data at 75 redshifts, we measure the half-mass epoch of halos and find that less massive halos tend to reach half of their current mass at higher redshifts. Simulation outputs including snapshot data, past lightcone space data, and halo merger data are available at http://sdss.kias.re.kr/astro/Horizon-Run4

  10. Nonperturbative light-front Hamiltonian methods

    NASA Astrophysics Data System (ADS)

    Hiller, J. R.

    2016-09-01

    We examine the current state-of-the-art in nonperturbative calculations done with Hamiltonians constructed in light-front quantization of various field theories. The language of light-front quantization is introduced, and important (numerical) techniques, such as Pauli-Villars regularization, discrete light-cone quantization, basis light-front quantization, the light-front coupled-cluster method, the renormalization group procedure for effective particles, sector-dependent renormalization, and the Lanczos diagonalization method, are surveyed. Specific applications are discussed for quenched scalar Yukawa theory, ϕ4 theory, ordinary Yukawa theory, supersymmetric Yang-Mills theory, quantum electrodynamics, and quantum chromodynamics. The content should serve as an introduction to these methods for anyone interested in doing such calculations and as a rallying point for those who wish to solve quantum chromodynamics in terms of wave functions rather than random samplings of Euclidean field configurations.

  11. Nonperturbative Regulator for Chiral Gauge Theories?

    NASA Astrophysics Data System (ADS)

    Grabowska, Dorota M.; Kaplan, David B.

    2016-05-01

    We propose a nonperturbative gauge-invariant regulator for d -dimensional chiral gauge theories on the lattice. The method involves simulating domain wall fermions in d +1 dimensions with quantum gauge fields that reside on one d -dimensional surface and are extended into the bulk via gradient flow. The result is a theory of gauged fermions plus mirror fermions, where the mirror fermions couple to the gauge fields via a form factor that becomes exponentially soft with the separation between domain walls. The resultant theory has a local d -dimensional interpretation only if the chiral fermion representation is anomaly free. A physical realization of this construction would imply the existence of mirror fermions in the standard model that are invisible except for interactions induced by vacuum topology, and which could gravitate differently than conventional matter.

  12. Gravitational contributions to the running Yang-Mills coupling in large extra-dimensional brane worlds

    NASA Astrophysics Data System (ADS)

    Ebert, Dietmar; Plefka, Jan; Rodigast, Andreas

    2009-02-01

    We study the question of a modification of the running gauge coupling of Yang-Mills theories due to quantum gravitational effects in a compact large extra dimensional brane world scenario with a low energy quantum gravity scale. The ADD scenario is applied for a D = d+δ dimensional space-time in which gravitons freely propagate, whereas the non-abelian gauge fields are confined to a d-dimensional brane. The extra dimensions are taken to be toroidal and the transverse fluctuation modes (branons) of the brane are taken into account. On this basis we have calculated the one-loop corrections due to virtual Kaluza-Klein graviton and branon modes for the gluon two- and three-point functions in an effective field theory treatment. Applying momentum cut-off regularization we find that for a d = 4 brane the leading gravitational divergencies cancel irrespective of the number of extra dimensions δ, generalizing previous results in the absence of extra-dimensions. Hence, again the Yang-Mills β-function receives no gravitational corrections at one-loop. This is no longer true in a `universal' extra dimensional scenario with a d > 4 dimensional brane. Moreover, the subleading power-law gravitational divergencies induce higher-dimensional counterterms, which we establish in our scheme. Interestingly, for d = 4 these gravitationally induced counterterms are of the form recently considered in non-abelian Lee-Wick extensions of the standard model—now with a possible mass scale in the TeV range due to the presence of large extra dimensions.

  13. Theory of hadronic nonperturbative models

    SciTech Connect

    Coester, F.; Polyzou, W.N.

    1995-08-01

    As more data probing hadron structure become available hadron models based on nonperturbative relativistic dynamics will be increasingly important for their interpretation. Relativistic Hamiltonian dynamics of few-body systems (constituent-quark models) and many-body systems (parton models) provides a precisely defined approach and a useful phenomenology. However such models lack a quantitative foundation in quantum field theory. The specification of a quantum field theory by a Euclidean action provides a basis for the construction of nonperturbative models designed to maintain essential features of the field theory. For finite systems it is possible to satisfy axioms which guarantee the existence of a Hilbert space with a unitary representation of the Poincare group and the spectral condition which ensures that the spectrum of the four-momentum operator is in the forward light cone. The separate axiom which guarantees locality of the field operators can be weakened for the construction for few-body models. In this context we are investigating algebraic and analytic properties of model Schwinger functions. This approach promises insight into the relations between hadronic models based on relativistic Hamiltonian dynamics on one hand and Bethe-Salpeter Green`s-function equations on the other.

  14. Nonperturbative vacuum and hard scattering processes

    SciTech Connect

    Sakai, N.

    1980-08-01

    A number of interesting suggestions for the QCD nonperturbative vacuum have been advocated in recent years by a group of people in Copenhagen. Some of the main ideas are briefly reviewed. An attempt to obtain the physical effects of the nonperturbative vacuum by studying hard scattering processes such as e/sup +/e/sup -/ ..-->.. hadrons is also described. 2 figures.

  15. The Power of Auditory-Motor Synchronization in Sports: Enhancing Running Performance by Coupling Cadence with the Right Beats

    PubMed Central

    Bood, Robert Jan; Nijssen, Marijn; van der Kamp, John; Roerdink, Melvyn

    2013-01-01

    Acoustic stimuli, like music and metronomes, are often used in sports. Adjusting movement tempo to acoustic stimuli (i.e., auditory-motor synchronization) may be beneficial for sports performance. However, music also possesses motivational qualities that may further enhance performance. Our objective was to examine the relative effects of auditory-motor synchronization and the motivational impact of acoustic stimuli on running performance. To this end, 19 participants ran to exhaustion on a treadmill in 1) a control condition without acoustic stimuli, 2) a metronome condition with a sequence of beeps matching participants’ cadence (synchronization), and 3) a music condition with synchronous motivational music matched to participants’ cadence (synchronization+motivation). Conditions were counterbalanced and measurements were taken on separate days. As expected, time to exhaustion was significantly longer with acoustic stimuli than without. Unexpectedly, however, time to exhaustion did not differ between metronome and motivational music conditions, despite differences in motivational quality. Motivational music slightly reduced perceived exertion of sub-maximal running intensity and heart rates of (near-)maximal running intensity. The beat of the stimuli –which was most salient during the metronome condition– helped runners to maintain a consistent pace by coupling cadence to the prescribed tempo. Thus, acoustic stimuli may have enhanced running performance because runners worked harder as a result of motivational aspects (most pronounced with motivational music) and more efficiently as a result of auditory-motor synchronization (most notable with metronome beeps). These findings imply that running to motivational music with a very prominent and consistent beat matched to the runner’s cadence will likely yield optimal effects because it helps to elevate physiological effort at a high perceived exertion, whereas the consistent and correct cadence induced by

  16. The power of auditory-motor synchronization in sports: enhancing running performance by coupling cadence with the right beats.

    PubMed

    Bood, Robert Jan; Nijssen, Marijn; van der Kamp, John; Roerdink, Melvyn

    2013-01-01

    Acoustic stimuli, like music and metronomes, are often used in sports. Adjusting movement tempo to acoustic stimuli (i.e., auditory-motor synchronization) may be beneficial for sports performance. However, music also possesses motivational qualities that may further enhance performance. Our objective was to examine the relative effects of auditory-motor synchronization and the motivational impact of acoustic stimuli on running performance. To this end, 19 participants ran to exhaustion on a treadmill in 1) a control condition without acoustic stimuli, 2) a metronome condition with a sequence of beeps matching participants' cadence (synchronization), and 3) a music condition with synchronous motivational music matched to participants' cadence (synchronization+motivation). Conditions were counterbalanced and measurements were taken on separate days. As expected, time to exhaustion was significantly longer with acoustic stimuli than without. Unexpectedly, however, time to exhaustion did not differ between metronome and motivational music conditions, despite differences in motivational quality. Motivational music slightly reduced perceived exertion of sub-maximal running intensity and heart rates of (near-)maximal running intensity. The beat of the stimuli -which was most salient during the metronome condition- helped runners to maintain a consistent pace by coupling cadence to the prescribed tempo. Thus, acoustic stimuli may have enhanced running performance because runners worked harder as a result of motivational aspects (most pronounced with motivational music) and more efficiently as a result of auditory-motor synchronization (most notable with metronome beeps). These findings imply that running to motivational music with a very prominent and consistent beat matched to the runner's cadence will likely yield optimal effects because it helps to elevate physiological effort at a high perceived exertion, whereas the consistent and correct cadence induced by auditory

  17. Non-perturbative String Theory from Water Waves

    SciTech Connect

    Iyer, Ramakrishnan; Johnson, Clifford V.; Pennington, Jeffrey S.; /SLAC

    2012-06-14

    We use a combination of a 't Hooft limit and numerical methods to find non-perturbative solutions of exactly solvable string theories, showing that perturbative solutions in different asymptotic regimes are connected by smooth interpolating functions. Our earlier perturbative work showed that a large class of minimal string theories arise as special limits of a Painleve IV hierarchy of string equations that can be derived by a similarity reduction of the dispersive water wave hierarchy of differential equations. The hierarchy of string equations contains new perturbative solutions, some of which were conjectured to be the type IIA and IIB string theories coupled to (4, 4k ? 2) superconformal minimal models of type (A, D). Our present paper shows that these new theories have smooth non-perturbative extensions. We also find evidence for putative new string theories that were not apparent in the perturbative analysis.

  18. Variational perturbation theory and nonperturbative calculations in QCD

    SciTech Connect

    Solovtsova, O. P.

    2013-10-15

    A nonperturbative approach based on the variational perturbation theory in quantum chromodynamics is developed. The variational series is different from the conventional perturbative expansion and can be used to go beyond the weak-coupling regime. The approach suggested takes into account the summation of threshold singularities and the involvement of nonperturbative light quark masses. Phenomenological applications of this approach to describe physical quantities connected with the hadronic {tau}-decay data: the R{sub {tau}} ratio, the light-quark Adler function, and the smeared R{sub {Delta}} function are presented. The description of examined quantities includes an infrared region and, therefore, they cannot be directly calculated within the standard perturbation theory. It is shown that in spite of this fact the approach suggested gives a rather good result for these quantities down to the lowest energy scale.

  19. Three-gluon running coupling from lattice QCD at N f = 2 + 1 + 1: a consistency check of the OPE approach

    NASA Astrophysics Data System (ADS)

    Boucaud, Ph.; Brinet, M.; De Soto, F.; Morenas, V.; Pène, O.; Petrov, K.; Rodríguez-Quintero, J.

    2014-04-01

    We present a lattice calculation of the renormalized running coupling constant in symmetric (MOM) and asymmetric momentum substraction schemes including u, d, s and c quarks in the sea. An Operator Product Expansion dominated by the dimension-two < A 2> condensate is used to fit the running of the coupling. We argue that the agreement in the predicted < A 2> condensate for both schemes is a strong support for the validity of the OPE approach and the effect of this non-gauge invariant condensate over the running of the strong coupling.

  20. Explicit solutions for effective four- and five-loop QCD running coupling

    NASA Astrophysics Data System (ADS)

    Cvetič, Gorazd; Kondrashuk, Igor

    2011-12-01

    We start with the explicit solution, in terms of the Lambert W function, of the renormalization group equation (RGE) for the gauge coupling in the supersymmetric Yang-Mills theory described by the well-known NSVZ β-function. We then construct a class of β-functions for which the RGE can be solved in terms of the Lambert W function. These β-functions are expressed in terms of a function which is a truncated Laurent series in the inverse u of the gauge coupling a ≡ α/π. The parameters in the Laurent series can be adjusted so that the first coefficients of the Taylor expansion of the β-function in the gauge coupling a reproduce the four-loop or five-loop QCD (or SQCD) β-function.

  1. Running coupling constant of ten-flavor QCD with the Schroedinger functional method

    SciTech Connect

    Hayakawa, M.; Uno, S.; Ishikawa, K.-I.; Osaki, Y.; Takeda, S.; Yamada, N.

    2011-04-01

    The walking technicolor theory attempts to realize electroweak symmetry breaking as the spontaneous chiral symmetry breakdown caused by the gauge dynamics with slowly varying gauge coupling constant and large mass anomalous dimension. Many-flavor QCD theories are candidates owning these features. We focus on the SU(3) gauge theory with ten flavors of massless fermions in the fundamental representation, and compute the gauge coupling constant in the Schroedinger functional scheme. Numerical simulation is performed with O(a)-unimproved lattice action, and the continuum limit is taken in linear in lattice spacing. We observe evidence that this theory possesses an infrared fixed point.

  2. Multi-Run Quantum Error Correction in Coupled Electron-Nuclear Systems

    NASA Astrophysics Data System (ADS)

    Rahimi Darabad, Robabeh; Park, Daniel K.; Baugh, Jonathan; Laflamme, Raymond

    2013-03-01

    It has been a milestone in realizing quantum computing, to enhance our control over physical systems so that making quantum processors performing accurately and precisely in presence of environmental noise. For practical uses, quantum error correction should be employed in multi-run cycles in order to keep the encoded qubit, that is carrying the information, safe from noise. We have been working towards implementing multi-run quantum error correction in molecular systems that involve electron and nuclear spins. Electron spins of a molecular sample are used for pumping up the nuclear spin polarizations, in addition to addressing and manipulating the nuclear spins. The required experimental conditions for having access to refreshable ancilla qubits are very much enhanced by a careful design of the molecular sample. We report the progress and prospects towards overcoming the experimental challenges in terms of sample preparation; irradiation imposed free electron samples, free radical molecular spin systems, and triplet state photoexcitable co-crystal samples. Industry of Canada, and CIFAR

  3. Supersymmetry and Nonperturbative Aspects in Quantum Cosmology

    NASA Astrophysics Data System (ADS)

    Donets, Evgueni E.; Tsulaia, Mirian M.

    The important question of the modern superstring and M - theories is the problem of the spontaneous breakdown of the supersymmetry. We consider the dynamical (nonperturbative) breaking of supersymmetry, caused by gravitational and Yang-Mills (YM) instantons in quantum cosmology.

  4. Controlling quark mass determinations non-perturbatively in three-flavour QCD

    NASA Astrophysics Data System (ADS)

    Campos, Isabel; Fritzsch, Patrick; Pena, Carlos; Preti, David; Ramos, Alberto; Vladikas, Anastassios

    2017-03-01

    The determination of quark masses from lattice QCD simulations requires a non-perturbative renormalization procedure and subsequent scale evolution to high energies, where a conversion to the commonly used \\overline {{{MS}}} scheme can be safely established. We present our results for the non-perturbative running of renormalized quark masses in Nf = 3 QCD between the electroweak and a hadronic energy scale, where lattice simulations are at our disposal. Recent theoretical advances in combination with well-established techniques allows to follow the scale evolution to very high statistical accuracy, and full control of systematic effects.

  5. Magnetic Effect Versus Thermal Effect on Quark Matter with a Running Coupling at Finite Densities

    NASA Astrophysics Data System (ADS)

    Yang, Li; Wen, Xin-Jian

    2017-05-01

    We investigate the quark matter in a strong magnetic field in the framework of SU(2) NJL model with a magnetic-field-dependent coupling. The spin polarization, the entropy per baryon, and the energy are studied by analyzing the competition of the magnetic effect and the thermal effect. The stronger magnetic field can enhance the spin polarization, arrange quarks in a uniform spin orientation, and change the energy per baryon drastically. However, it can hardly affect the entropy per baryon, which is dominated by the temperature. As the temperature increases, more quarks will be excited from the lowest Landau level up to higher Landau levels. Supported by the National Natural Science Foundation of China under Grant Nos. 11475110, 11135011, and 11575190

  6. Analytic, nonperturbative, almost exact QED: The two-point functions

    SciTech Connect

    Fried, H. M.; Gabellini, Y.

    2009-03-15

    Based on the choice of a special gauge, in which a useful form of scaling invariance holds, a new method is suggested for the analytic, nonperturbative calculation of the n-point functions of QED. A modified functional analysis is employed in configuration space, where the dressed electron and photon propagators (in quenched approximation) are each found to be simple products of the relevant free propagator with an appropriate function of configuration space variables containing all powers of the square of the coupling constant.

  7. Nonperturbative theory of exciton-phonon resonances in semiconductor absorption

    NASA Astrophysics Data System (ADS)

    Hannewald, K.; Bobbert, P. A.

    2005-09-01

    We develop a theory of exciton-phonon sidebands in the absorption spectra of semiconductors. The theory does not rely on an ad hoc exciton-phonon picture, but is based on a more fundamental electron-phonon Hamiltonian, thus avoiding a priori assumptions about excited-state properties. We derive a nonperturbative compact solution that can be looked upon as the semiconductor version of the textbook absorption formula for a two-level system coupled to phonons. Accompanied by an illustrative numerical example, the importance and usefulness of our approach with respect to practical applications for semiconductors is demonstrated.

  8. Particle multiplicities in lead-lead collisions at the CERN large hadron collider from nonlinear evolution with running coupling corrections.

    PubMed

    Albacete, Javier L

    2007-12-31

    We present predictions for the pseudorapidity density of charged particles produced in central Pb-Pb collisions at the LHC. Particle production in such collisions is calculated in the framework of k(t) factorization. The nuclear unintegrated gluon distributions at LHC energies are determined from numerical solutions of the Balitsky-Kovchegov equation including recently calculated running coupling corrections. The initial conditions for the evolution are fixed by fitting Relativistic Heavy Ion Collider data at collision energies square root[sNN]=130 and 200 GeV per nucleon. We obtain dNch(Pb-Pb)/deta(square root[sNN]=5.5 TeV)/eta=0 approximately 1290-1480.

  9. Non-perturbative QCD and hadron physics

    NASA Astrophysics Data System (ADS)

    Cobos-Martínez, J. J.

    2016-10-01

    A brief exposition of contemporary non-perturbative methods based on the Schwinger-Dyson (SDE) and Bethe-Salpeter equations (BSE) of Quantum Chromodynamics (QCD) and their application to hadron physics is given. These equations provide a non-perturbative continuum formulation of QCD and are a powerful and promising tool for the study of hadron physics. Results on some properties of hadrons based on this approach, with particular attention to the pion distribution amplitude, elastic, and transition electromagnetic form factors, and their comparison to experimental data are presented.

  10. Nonperturbative atom-photon interactions in an optical cavity

    SciTech Connect

    Carmichael, H.J.; Tian, L.; Ren, W.

    1994-12-31

    One of the principal developments in cavity quantum electrodynamics in the last few years has been the extension of the ideas originally applied to systems of Rydberg atoms in microwave cavities to optical frequencies. As a corollary of this, more attention is being paid to quantum fluctuations and photon statistics. Another development, still in its infancy, is a move toward experiments using slowed or trapped atoms, or velocity selected beams; these methods are needed to enter the nonperturbative (strong dipole coupling) regime for one atom where there are experiments on subtle quantum-statistical effects go carry out. In this chapter we solve a number of theoretical problems related to these themes. Although the focus of the work is on optical systems, most of what we do is also relevant at microwave frequencies. We emphasize quantum fluctuations and photon statistics, and we try always to separate the quantum physics from those aspects of the physics that are understandable in classical terms. On the whole we only pay attention to the nonperturbative regime of cavity quantum electrodynamics where the dipole coupling strength is larger than the dissipation rates. 59 refs., 14 figs.

  11. A quenched study of the Schroedinger functional with chirally rotated boundary conditions: non-perturbative tuning

    SciTech Connect

    Gonzalez-Lopez, Jennifer; Jansen, Karl; Renner, Dru B.; Shindler, Andrea

    2013-02-01

    The use of chirally rotated boundary conditions provides a formulation of the Schroedinger functional that is compatible with automatic O(a) improvement of Wilson fermions up to O(a) boundary contributions. The elimination of bulk O(a) effects requires the non-perturbative tuning of the critical mass and one additional boundary counterterm. We present the results of such a tuning in a quenched setup for several values of the renormalized gauge coupling, from perturbative to non-perturbative regimes, and for a range of lattice spacings. We also check that the correct boundary conditions and symmetries are restored in the continuum limit.

  12. Nonperturbative contributions from complexified solutions in C PN -1 models

    NASA Astrophysics Data System (ADS)

    Fujimori, Toshiaki; Kamata, Syo; Misumi, Tatsuhiro; Nitta, Muneto; Sakai, Norisuke

    2016-11-01

    We discuss the nonperturbative contributions from real and complex saddle point solutions in the C P1 quantum mechanics with fermionic degrees of freedom, using the Lefschetz thimble formalism beyond the Gaussian approximation. We find bion solutions, which correspond to (complexified) instanton-anti-instanton configurations stabilized in the presence of the fermionic degrees of freedom. By computing the one-loop determinants in the bion backgrounds, we obtain the leading order contributions from both the real and complex bion solutions. To incorporate quasizero modes which become nearly massless in a weak coupling limit, we regard the bion solutions as well-separated instanton-anti-instanton configurations and calculate a complexified quasimoduli integral based on the Lefschetz thimble formalism. The nonperturbative contributions from the real and complex bions are shown to cancel out in the supersymmetric case and give an (expected) ambiguity in the nonsupersymmetric case, which plays a vital role in the resurgent trans-series. For nearly supersymmetric situations, evaluation of the Lefschetz thimble gives results in precise agreement with those of the direct evaluation of the Schrödinger equation. We also perform the same analysis for the sine-Gordon quantum mechanics and point out some important differences showing that the sine-Gordon quantum mechanics does not correctly describe the 1d limit of the C PN -1 field theory of R ×S1.

  13. Nonperturbative analytical approximate solutions in intrinsically nonlinear systems

    NASA Astrophysics Data System (ADS)

    Kindall, Kevin Gaylynn

    The basis for obtaining analytical approximations in this dissertation is a new nonperturbative iterative approach that preserves the intrinsic nonlinearity of the system. The traditional method for approaching nonlinear equations has been the small amplitude approximation of classical perturbation theory. However, it is becoming increasingly evident that intrinsic nonlinearity or persistence of the interaction is a primary feature of the solutions for the nonlinear equations that have been solved. Although perturbation theory may be useful in certain physical domains, it is a domain which excludes the effects of the persistent interaction, since perturbation theory nullifies any intrinsically nonlinear property. The method of solution used here proceeds by analogy to the well-known result that second order, linear ordinary differential equations can be transformed to a Riccati equation by a change in dependent variable. An analogous transformation for nonlinear partial differential equations leads to a set of integro- differential equations for which the basic structure is Riccati. Approximations are introduced in the integral part of the integro-differential equation which allow for systematic iteration while making no expansion in powers of the coupling constant. Two sets of differential equations are examined: the Maxwell-Bloch set and the Rossler set. The importance of the former lies in its importance to the phenomenon of optical bistability. The latter represents the minimal set necessary to display chaos. In each case, their intrinsic nonlinearity is demonstrated, and nonperturbative approximate solutions are constructed.

  14. Methods in QCD and non-perturbative physics

    NASA Astrophysics Data System (ADS)

    Lee, Dean Junyuel

    1998-11-01

    This thesis explores several new and different methods in the study of QCD and non-perturbative field theory. In Chapter 1 we introduce a sum-rule for large-Nc QCD which relates the density of heavy quarkonium states, the state-averaged square of the wavefunction at the origin, and the heavy quark current-current correlator. Focusing on the region of energy just above perturbative threshold, we calculate the correlator by incorporating arbitrarily high orders in the QCD coupling αs. We use the sum-rule to determine the bottomonium potential using experimentally measured s- wave leptonic widths and compare the result with the potential obtained by direct calculation from the measured s-wave spectrum. We discuss the utility of the sum-rule method for accurate determination of the confining potential. In Chapter 2 we study the singular Landau surfaces of planar diagrams contributing to scattering of a massless quark and antiquark in 3 + 1 dimensions. In particular, we look at singularities which remain after integration with respect to the various angular degrees of freedom. We derive a general relation between these singularities and the singularities of quark-antiquark scattering in 1 + 1 dimensions. We then classify all Landau surfaces of the 1 + 1 dimensional system. Combining these results, we deduce that the singular surfaces of the angle-integrated 3 + 1 dimensional amplitude must satisfy at least one of three conditions, which we call the planar light-cone conditions. We discuss the extension of our results to non-perturbative processes by means of the non- perturbative operator product expansion. Our findings offer new insights into the connection between the 't Hooft model and large-Nc mesons in 3 + 1 dimensions and may prove useful in studies of confinement in relativistic meson systems. In Chapter 3 we introduce a new technique called spherical field theory. Spherical field theory is a non-perturbative method for studying quantum field theories. It uses

  15. Nonperturbative evolution of parton quasi-distributions

    NASA Astrophysics Data System (ADS)

    Radyushkin, A. V.

    2017-04-01

    Using the formalism of parton virtuality distribution functions (VDFs) we establish a connection between the transverse momentum dependent distributions (TMDs) F (x , k⊥2) and quasi-distributions (PQDs) Q (y ,p3) introduced recently by X. Ji for lattice QCD extraction of parton distributions f (x). We build models for PQDs from the VDF-based models for soft TMDs, and analyze the p3 dependence of the resulting PQDs. We observe a strong nonperturbative evolution of PQDs for small and moderately large values of p3 reflecting the transverse momentum dependence of TMDs. Thus, the study of PQDs on the lattice in the domain of strong nonperturbative effects opens a new perspective for investigation of the 3-dimensional hadron structure.

  16. Nonperturbative methods in HZE ion transport

    NASA Technical Reports Server (NTRS)

    Wilson, John W.; Badavi, Francis F.; Costen, Robert C.; Shinn, Judy L.

    1993-01-01

    A nonperturbative analytic solution of the high charge and energy (HZE) Green's function is used to implement a computer code for laboratory ion beam transport. The code is established to operate on the Langley Research Center nuclear fragmentation model used in engineering applications. Computational procedures are established to generate linear energy transfer (LET) distributions for a specified ion beam and target for comparison with experimental measurements. The code is highly efficient and compares well with the perturbation approximations.

  17. Non-perturbative study of QCD correlators

    NASA Astrophysics Data System (ADS)

    Lokhov, A. Y.

    2006-07-01

    This PhD dissertation is devoted to a non-perturbative study of QCD correlators. The main tool that we use is lattice QCD. We concentrated our efforts on the study of the main correlators of the pure Yang - Mills theory in the Landau gauge, namely the ghost and the gluon propagators. We are particularly interested in determining the Lqcd parameter. It is extracted by means of perturbative predictions available up to NNNLO. The related topic is the influence of non-perturbative effects that show up as appearance of power-corrections to the low-momentum behaviour of the Green functions. A new method of removing these power corrections allows a better estimate of Lqcd. Our result is Lambda^{n_f=0}_{ms} = 269(5)^{+12}_{-9} MeV. Another question that we address is the infrared behaviour of Green functions, at momenta of order and below Lqcd. At low energy the momentum dependence of the propagators changes considerably, and this is probably related to confinement. The lattice approach allows to check the predictions of analytical methods because it gives access to non-perturbative correlators. According to our analysis the gluon propagator is finite and non-zero at vanishing momentum, and the power-law behaviour of the ghost propagator is the same as in the free case.

  18. Ground-state correlations within a nonperturbative approach

    NASA Astrophysics Data System (ADS)

    De Gregorio, G.; Herko, J.; Knapp, F.; Lo Iudice, N.; Veselý, P.

    2017-02-01

    The contribution of the two-phonon configurations to the ground state of 4He and 16O is evaluated nonperturbatively using a Hartree-Fock basis within an equation-of-motion phonon method using a nucleon-nucleon optimized chiral potential. Convergence properties of energies and root-mean-square radii versus the harmonic oscillator frequency and space dimensions are investigated. The comparison with the second-order perturbation theory calculations shows that the higher-order terms have an appreciable repulsive effect and yield too-small binding energies and nuclear radii. It is argued that four-phonon configurations, through their strong coupling to two phonons, may provide most of the attractive contribution necessary for filling the gap between theoretical and experimental quantities. Possible strategies for accomplishing such a challenging task are discussed.

  19. Phase diagram of superconductors from nonperturbative flow equations

    SciTech Connect

    Bergerhoff, B.; Freire, F.; Litim, D.F.; Lola, S.; Wetterich, C.

    1996-03-01

    The universal behavior of superconductors near the phase transition is described by the three-dimensional field theory of scalar quantum electrodynamics. We approximately solve the model with the help of nonperturbative flow equations. A first- or second-order phase transition is found depending on the relative strength of the scalar versus the gauge coupling. The region of a second-order phase transition is governed by a fixed point of the flow equations with associated critical exponents. We also give an approximate description of the tricritical behavior and briefly discuss the crossover relevant for the onset of scaling near the critical temperature. Final confirmation of a second-order transition for strong type-II superconductors requires further analysis with extended truncations of the flow equations. {copyright} {ital 1996 The American Physical Society.}

  20. P-Wave hyperons in nonperturbative quark dynamics

    SciTech Connect

    Driga, O. N. Narodetskii, I. M. Veselov, A. I.

    2008-02-15

    We carry out an investigation of the P-wave hyperons {lambda} {sigma}, and {xi} employing the field correlator method in QCD. This method allows us to derive the effective Hamiltonian (EH) approach successfully applied to the meson and ground-state baryon spectra. The EH is written in the form of the nonrelativistic three-quark Hamiltonian with perturbative Coulomb-like and nonperturbative string interactions and the specific mass term. We solve the three-quark problem using the hyperspherical approach. With only two parameters, the string tension {sigma} and the strong coupling constant {alpha}{sub s}, a unified quantitative description of the ground and excited hyperon states is achieved. In particular, we predict that all the hyperon states have the similar cost (in {delta}) {approx}460 MeV.

  1. P-Wave hyperons in nonperturbative quark dynamics

    SciTech Connect

    Driga, O. N. Narodetskii, I. M. Veselov, A. I.

    2008-02-15

    We carry out an investigation of the P-wave hyperons {Lambda} {Sigma}, and {xi} employing the field correlator method in QCD. This method allows us to derive the effective Hamiltonian (EH) approach successfully applied to the meson and ground-state baryon spectra. The EH is written in the form of the nonrelativistic three-quark Hamiltonian with perturbative Coulomb-like and nonperturbative string interactions and the specific mass term. We solve the three-quark problem using the hyperspherical approach. With only two parameters, the string tension {sigma} and the strong coupling constant {alpha}{sub s}, a unified quantitative description of the ground and excited hyperon states is achieved. In particular, we predict that all the hyperon states have the similar cost (in {Delta}) {approx}460 MeV.

  2. Non-perturbative QCD amplitudes in quenched and eikonal approximations

    SciTech Connect

    Fried, H.M.; Grandou, T.; Sheu, Y.-M.

    2014-05-15

    Even though approximated, strong coupling non-perturbative QCD amplitudes remain very difficult to obtain. In this article, in eikonal and quenched approximations at least, physical insights are presented that rely on the newly-discovered property of effective locality. The present article also provides a more rigorous mathematical basis for the crude approximations used in the previous derivation of the binding potential of quarks and nucleons. Furthermore, the techniques of Random Matrix calculus along with Meijer G-functions are applied to analyze the generic structure of fermionic amplitudes in QCD. - Highlights: • We discuss the physical insight of effective locality to QCD fermionic amplitudes. • We show that an unavoidable delta function goes along with the effective locality property. • The generic structure of QCD fermion amplitudes is obtained through Random Matrix calculus.

  3. Yang-Mills condensate as dark energy: A nonperturbative approach

    NASA Astrophysics Data System (ADS)

    Donà, Pietro; Marcianò, Antonino; Zhang, Yang; Antolini, Claudia

    2016-02-01

    Models based on the Yang-Mills condensate (YMC) have been advocated for in the literature and claimed as successful candidates for explaining dark energy. Several variations on this simple idea have been considered, the most promising of which are reviewed here. Nevertheless, the previously attained results relied heavily on the perturbative approach to the analysis of the effective Yang-Mills action, which is only adequate in the asymptotically free limit, and were extended into a regime, the infrared limit, in which confinement is expected. We show that if a minimum of the effective Lagrangian in θ =-Fμν aFa μ ν/2 exists, a YMC forms that drives the Universe toward an accelerated de Sitter phase. The details of the models depend weakly on the specific form of the effective Yang-Mills Lagrangian. Using nonperturbative techniques mutated from the functional renormalization-group procedure, we finally show that the minimum in θ of the effective Lagrangian exists. Thus, a YMC can actually take place. The nonperturbative model has properties similar to the ones in the perturbative model. In the early stage of the Universe, the YMC equation of state has an evolution that resembles the radiation component, i.e., wy→1 /3 . However, in the late stage, wy naturally runs to the critical state with wy=-1 , and the Universe transitions from a matter-dominated into a dark energy dominated stage only at latest time, at a redshift whose value depends on the initial conditions that are chosen while solving the dynamical system.

  4. Heavy quark potential from QCD-related effective coupling

    NASA Astrophysics Data System (ADS)

    Ayala, César; González, Pedro; Vento, Vicente

    2016-12-01

    We implement our past investigations of quark-antiquark interaction through a non-perturbative running coupling defined in terms of a gluon mass function, similar to that used in some Schwinger-Dyson approaches. This coupling leads to a quark-antiquark potential, which satisfies not only asymptotic freedom but also describes linear confinement correctly. From this potential, we calculate the bottomonium and charmonium spectra below the first open flavor meson-meson thresholds and show that for a small range of values of the free parameter determining the gluon mass function an excellent agreement with data is attained.

  5. Catalysis in the Service of Green Chemistry: Nobel Prize-Winning Palladium-Catalysed Cross-Couplings, Run in Water at Room Temperature

    PubMed Central

    Lipshutz, Bruce H.; Taft, Benjamin R.; Abela, Alexander R.; Ghorai, Subir; Krasovskiy, Arkady; Duplais, Christophe

    2012-01-01

    Palladium-catalysed cross-couplings, in particular Heck, Suzuki-Miyaura and Negishi reactions developed over three decades ago, are routinely carried out in organic solvents. However, alternative media are currently of considerable interest given an increasing emphasis on making organic processes ‘greener’; for example, by minimising organic waste in the form of organic solvents. Water is the obvious leading candidate in this regard. Hence, this review focuses on the application of micellar catalysis, in which a ‘designer’ surfactant enables these award-winning coupling reactions to be run in water at room temperature. PMID:23555153

  6. Numerical analysis of the Balitsky-Kovchegov equation with running coupling: Dependence of the saturation scale on nuclear size and rapidity

    SciTech Connect

    Albacete, J.L.; Armesto, N.; Salgado, C.A.; Wiedemann, U.A.; Milhano, J.G.

    2005-01-01

    We study the effects of including a running coupling constant in high-density QCD evolution. For fixed coupling constant, QCD evolution preserves the initial dependence of the saturation momentum Q{sub s} on the nuclear size A and results in an exponential dependence on rapidity Y, Q{sub s}{sup 2}(Y)=Q{sub s}{sup 2}(Y{sub 0})exp[{alpha}{sub s}d(Y-Y{sub 0})]. For the running coupling case, we rederive analytical estimates for the A and Y dependences of the saturation scale and test them numerically. The A dependence of Q{sub s} vanishes {proportional_to}1/{radical}(Y) for large A and Y. The Y dependence is reduced to Q{sub s}{sup 2}(Y){proportional_to}exp({delta}{sup '}{radical}(Y+X)), where we find numerically {delta}{sup '}{approx_equal}3.2. We study the behavior of the gluon distribution at large transverse momentum, characterizing it by an anomalous dimension 1-{gamma}, which we define in a fixed region of small dipole sizes. In contrast to previous analytical work, we find a marked difference between the fixed coupling ({gamma}{approx_equal}0.65) and running coupling ({gamma}{approx}0.85) results. Our numerical findings show that both a scaling function depending only on the variable rQ{sub s} and the perturbative double-leading-logarithmic expression provide equally good descriptions of the numerical solutions for very small r values below the so-called scaling window.

  7. Nonperturbative comparison of QCD effective charges

    SciTech Connect

    Aguilar, A. C.; Binosi, D.; Papavassiliou, J.; Rodriguez-Quintero, J.

    2009-10-15

    We study the nonperturbative behavior of two versions of the QCD effective charge, one obtained from the pinch technique gluon self-energy, and one from the ghost-gluon vertex. Despite their distinct theoretical origin, due to a fundamental identity relating various ingredients appearing in their respective definitions, the two effective charges are almost identical in the entire range of physical momenta, and coincide exactly in the deep infrared, where they freeze at a common finite value. Specifically, the dressing function of the ghost propagator is related to the two form factors in the Lorentz decomposition of a certain Green's function, appearing in a variety of field-theoretic contexts. The central identity, which is valid only in the Landau gauge, is derived from the Schwinger-Dyson equations governing the dynamics of the aforementioned quantities. The renormalization procedure that preserves the validity of the identity is carried out, and various relevant kinematic limits and physically motivated approximations are studied in detail. A crucial ingredient in this analysis is the infrared finiteness of the gluon propagator, which is inextricably connected with the aforementioned freezing of the effective charges. Some important issues related to the consistent definition of the effective charge in the presence of such a gluon propagator are resolved. We finally present a detailed numerical study of a special set of Schwinger-Dyson equations, whose solutions determine the nonperturbative dynamics of the quantities composing the two effective charges.

  8. Communications: A nonperturbative quantum master equation approach to charge carrier transport in organic molecular crystals.

    PubMed

    Wang, Dong; Chen, Liping; Zheng, Renhui; Wang, Linjun; Shi, Qiang

    2010-02-28

    We present a nonperturbative quantum master equation to investigate charge carrier transport in organic molecular crystals based on the Liouville space hierarchical equations of motion method, which extends the previous stochastic Liouville equation and generalized master equation methods to a full quantum treatment of the electron-phonon coupling. Diffusive motion of charge carriers in a one-dimensional model in the presence of nonlocal electron-phonon coupling was studied, and two different charge carrier diffusion mechanisms are observed for large and small average intermolecular couplings. The new method can also find applications in calculating spectra and energy transfer in various types of quantum aggregates where the perturbative treatments fail.

  9. Running Away

    MedlinePlus

    ... Emergency Room? What Happens in the Operating Room? Running Away KidsHealth > For Kids > Running Away A A ... life on the streets. continue The Reality of Running Away When you think about running away, you ...

  10. Ghost-gluon coupling, power corrections, and {Lambda}{sub MS} from twisted-mass lattice QCD at N{sub f}=2

    SciTech Connect

    Blossier, B.; Boucaud, Ph.; Gravina, M.; Pene, O.; De soto, F.; Morenas, V.

    2010-08-01

    We present results concerning the nonperturbative evaluation of the ghost-gluon running QCD coupling constant from N{sub f}=2 twisted-mass lattice calculations. A novel method for calibrating the lattice spacing, independent of the string tension and hadron spectrum, is presented with results in agreement with previous estimates. The value of {Lambda}{sub MS} is computed from the running of the QCD coupling only after extrapolating to zero dynamical quark mass and after removing a nonperturbative operator-product expansion contribution that is assumed to be dominated by the dimension-two gluon condensate. The effect due to the dynamical quark mass in the determination of {Lambda}{sub MS} is discussed.

  11. Well liner running shoe

    SciTech Connect

    Bell, J.F.

    1994-01-11

    Wellbore liners are set with a running shoe comprising a cylindrical body, end cap, check valve and receiver member in assembly. The receiver member includes threads for receiving the coupling sleeve of a running tool, and retaining wickers for engagement with a cement plug or dart to retain the same permanently engaged with and blocking the flow of fluid through the running shoe. A running tool for use with the shoe includes a coupling sleeve which is retained on a support mandrel by a collar which is secured to the mandrel with a shear pin so that pressuring up the workstring, in the event of a stuck coupling sleeve, will permit retrieval of the main part of the running tool and the workstring. The interior parts of the running shoe are made of aluminum or plastic for easy drill-out to extend the wellbore beyond the end of the liner. 3 figs.

  12. Nonperturbative Quantum Physics from Low-Order Perturbation Theory.

    PubMed

    Mera, Héctor; Pedersen, Thomas G; Nikolić, Branislav K

    2015-10-02

    The Stark effect in hydrogen and the cubic anharmonic oscillator furnish examples of quantum systems where the perturbation results in a certain ionization probability by tunneling processes. Accordingly, the perturbed ground-state energy is shifted and broadened, thus acquiring an imaginary part which is considered to be a paradigm of nonperturbative behavior. Here we demonstrate how the low order coefficients of a divergent perturbation series can be used to obtain excellent approximations to both real and imaginary parts of the perturbed ground state eigenenergy. The key is to use analytic continuation functions with a built-in singularity structure within the complex plane of the coupling constant, which is tailored by means of Bender-Wu dispersion relations. In the examples discussed the analytic continuation functions are Gauss hypergeometric functions, which take as input fourth order perturbation theory and return excellent approximations to the complex perturbed eigenvalue. These functions are Borel consistent and dramatically outperform widely used Padé and Borel-Padé approaches, even for rather large values of the coupling constant.

  13. Nonperturbative moduli superpotential with positive exponents

    NASA Astrophysics Data System (ADS)

    Abe, Hiroyuki; Higaki, Tetsutaro; Kobayashi, Tatsuo; Seto, Osamu

    2008-07-01

    We study nonperturbative moduli superpotentials with positive exponents, i.e. the form like AeaT with a positive constant a and the modulus T. These effects can be generated, e.g., by D-branes which have negative Ramond-Ramond charge of the lower-dimensional D-brane. The scalar potentials including such terms have quite a rich structure. There are several local minima with different potential energies and a high barrier, whose height is of O(Mp4). We discuss their implications from the viewpoints of cosmology and particle phenomenology, e.g. the realization of inflation models, avoiding the overshooting problem. This type of potential would be useful to realize the inflation and low-energy supersymmetry breaking.

  14. Nonperturbative decay of supersymmetric flat directions

    SciTech Connect

    Guemruekcueoglu, A. Emir; Peloso, Marco; Sexton, Matthew; Olive, Keith A.

    2008-09-15

    We compute the nonperturbative decay of supersymmetric flat directions due to their D-term potential. Flat directions can develop large vacuum expectation values during inflation, and, if they are long-lived, this can strongly affect the reheating and thermalization stages after the inflation. We study a generic system of two U(1) or SU(2) flat directions which are cosmologically evolving after inflation. After proper gauge fixing, we show that the excitations of the fields around this background can undergo exponential amplification, at the expense of the energy density of the flat directions. We compute this effect for several values of the masses and the initial vacuum expectation values of the two flat directions, through a combination of analytical methods and extensive numerical simulations.

  15. A nonperturbative fermion-boson vertex

    NASA Astrophysics Data System (ADS)

    Bashir, A.; Raya, A.

    2002-07-01

    We calculate the massive fermion propagator at one-loop order in QED3. The Ward-Takahashi identity (WTI) relates the propagator to the vertex. This allows us to split the vertex into its longitudinal and transverse parts. The former is fixed by the WTI. Following the scheme of Ball and Chiu later modified by Kizilersu et. al., we calculate the full vertex at one-loop order. A mere subtraction of the longitudinal part of the vertex gives us the transverse part. The alpha dependence in the transverse vertex can be eliminated by making use of the perturbative expressions for the wavefunction renormalization function and the mass function of complicated arguments of the incoming and outgoing fermion momenta. This leads us to a vertex which is nonperturbative in nature. We also calculate an effective vertex for which the arguments of the unknown functions have no angular dependence, making it particularly suitable for numerical studies of dynamical symmetry breaking.

  16. Phenomenology of nonperturbative charm in the nucleon

    SciTech Connect

    Hobbs, T. J.; Londergan, J. T.; Melnitchouk, W.

    2014-04-02

    We perform a comprehensive analysis of the role of nonperturbative (or intrinsic) charm in the nucleon, generated through Fock state expansions of the nucleon wave function involving five-quark virtual states represented by charmed mesons and baryons. We consider contributions from a variety of charmed meson-baryon states and find surprisingly dominant effects from the D¯*0 Λc+ configuration. We pay particular attention to the existence and persistence of high-x structure for intrinsic charm, and the x dependence of the c-c¯ asymmetry predicted in meson-baryon models. We discuss how studies of charmed baryons and mesons in hadronic reactions can be used to constrain models, and outline future measurements that could further illuminate the intrinsic charm component of the nucleon.

  17. Nonperturbative calculation of phonon effects on spin squeezing

    NASA Astrophysics Data System (ADS)

    Dylewsky, D.; Freericks, J. K.; Wall, M. L.; Rey, A. M.; Foss-Feig, M.

    2016-01-01

    Theoretical models of spins coupled to bosons provide a simple setting for studying a broad range of important phenomena in many-body physics, from virtually mediated interactions to decoherence and thermalization. In many atomic, molecular, and optical systems, such models also underlie the most successful attempts to engineer strong, long-ranged interactions for the purpose of entanglement generation. Especially when the coupling between the spins and bosons is strong, such that it cannot be treated perturbatively, the properties of such models are extremely challenging to calculate theoretically. Here, exact analytical expressions for nonequilibrium spin-spin correlation functions are derived for a specific model of spins coupled to bosons. The spatial structure of the coupling between spins and bosons is completely arbitrary, and thus the solution can be applied to systems in any number of dimensions. The explicit and nonperturbative inclusion of the bosons enables the study of entanglement generation (in the form of spin squeezing) even when the bosons are driven strongly and near resonantly, and thus provides a quantitative view of the breakdown of adiabatic elimination that inevitably occurs as one pushes towards the fastest entanglement generation possible. The solution also helps elucidate the effect of finite temperature on spin squeezing. The model considered is relevant to a variety of atomic, molecular, and optical systems, such as atoms in cavities or trapped ions. As an explicit example, the results are used to quantify phonon effects in trapped ion quantum simulators, which are expected to become increasingly important as these experiments push towards larger numbers of ions.

  18. Nonperturbative Pauli-Villars regularization of vacuum polarization in light-front QED

    SciTech Connect

    Chabysheva, Sophia S.; Hiller, John R.

    2010-08-01

    We continue the development of a nonperturbative light-front Hamiltonian method for the solution of quantum field theories by considering the one-photon eigenstate of Lorentz-gauge QED. The photon state is computed nonperturbatively for a Fock basis with a bare photon state and electron-positron pair states. The calculation is regulated by the inclusion of Pauli-Villars (PV) fermions, with one flavor to make the integrals finite and a second flavor to guarantee a zero mass for the physical photon eigenstate. We compute in detail the constraints on the PV coupling strengths that this zero mass implies. As part of this analysis, we provide the complete Lorentz-gauge light-front QED Hamiltonian with two PV fermion flavors and two PV photon flavors, which will be useful for future work. The need for two PV photons was established previously; the need for two PV fermions is established here.

  19. Coupling of nanoflow liquid chromatography to matrix-assisted laser desorption/ionization mass spectrometry: real-time liquid chromatography run mapping on a MALDI plate.

    PubMed

    Nägele, Edgar; Vollmer, Martin

    2004-01-01

    The major obstacle in the use of matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) instruments in the analysis of complex proteome samples is the lack of a direct coupling of a highly resolving separation technique with the mass spectrometer itself. To overcome this drawback, a spotting device for capillary and nanoflow liquid chromatography (LC) with a special liquid deposition principle for lowest volumes was developed. The instrument is able to perform MALDI spotting in real time in order to deposit the LC run on the MALDI plate, and therefore couples the high resolution power of nano-RP-HPLC separation directly with MALDI-MS. This work describes the development and optimization of a method for spotting with online matrix addition, and illustrates its use in the analysis of a complex proteome sample.

  20. Nonperturbative QCD and elastic processes at CEBAF energies

    SciTech Connect

    Radyushkin, A.V. |

    1994-04-01

    The author outlines how one can approach nonperturbative aspects of the QCD dynamics studying elastic processes at energies accessible at upgraded CEBAF. The author`s point is that, in the absence of a complete theory of the nonperturbative effects, a possible way out is based on a systematic use of the QCD factorization procedure which separates theoretically understood ({open_quotes}known{close_quotes}) short-distance effects and nonperturbative ({open_quotes}unknown{close_quotes}) long-distance ones. The latter include hadronic distribution amplitudes, soft components of hadronic form factors etc. Incorporating the QCD sum rule version of the QCD factorization approach, one can relate these nonperturbative functions to more fundamental objects, vacuum condensates, which accumulate information about the nonperturbative structure of the QCD vacuum. The emerging QCD sum rule picture of hadronic form factors is characterized by a dominant role of essentially nonperturbative effects in the few GeV region, with perturbative mechanisms starting to show up for momentum transfers Q{sup 2} closer to 10 GeV{sup 2} and higher. Thus, increasing CEBAF energy provides a unique opportunity for a precision study of interplay between the perturbative and nonperturbative phenomena in the QCD description of elastic processes.

  1. Nonperturbative Casimir effect and monopoles: Compact Abelian gauge theory in two spatial dimensions

    NASA Astrophysics Data System (ADS)

    Chernodub, M. N.; Goy, V. A.; Molochkov, A. V.

    2017-04-01

    We demonstrate that Casimir forces associated with zero-point fluctuations of quantum vacuum may be substantially affected by the presence of dynamical topological defects. In order to illustrate this nonperturbative effect we study the Casimir interactions between dielectric wires in a compact formulation of Abelian gauge theory in two spatial dimensions. The model possesses topological defects, instantonlike monopoles, which are known to be responsible for nonperturbative generation of a mass gap and for a linear confinement of electrically charged probes. Despite the fact the model has no matter fields, the Casimir energy depends on the value of the gauge coupling constant. We show, both analytically and numerically, that in the strong coupling regime the Abelian monopoles make the Casimir forces short ranged. Simultaneously, their presence increases the interaction strength between the wires at short distances for a certain range of values of the gauge coupling. The wires suppress monopole density in the space between them compared to the density outside the wires. In the weak coupling regime the monopoles become dilute and the Casimir potential reduces to a known theoretical result that does not depend on the gauge coupling.

  2. Nonperturbative approach to circuit quantum electrodynamics.

    PubMed

    Jonasson, Olafur; Tang, Chi-Shung; Goan, Hsi-Sheng; Manolescu, Andrei; Gudmundsson, Vidar

    2012-10-01

    We outline a rigorous method which can be used to solve the many-body Schrödinger equation for a Coulomb interacting electronic system in an external classical magnetic field as well as a quantized electromagnetic field. Effects of the geometry of the electronic system as well as the polarization of the quantized electromagnetic field are explicitly taken into account. We accomplish this by performing repeated truncations of many-body spaces in order to keep the size of the many particle basis on a manageable level. The electron-electron and electron-photon interactions are treated in a nonperturbative manner using "exact numerical diagonalization." Our results demonstrate that including the diamagnetic term in the photon-electron interaction Hamiltonian drastically improves numerical convergence. Additionally, convergence with respect to the number of photon states in the joint photon-electron Fock space basis is fast. However, the convergence with respect to the number of electronic states is slow and is the main bottleneck in calculations.

  3. Non-perturbative effects in spin glasses

    NASA Astrophysics Data System (ADS)

    Castellana, Michele; Parisi, Giorgio

    2015-03-01

    We present a numerical study of an Ising spin glass with hierarchical interactions--the hierarchical Edwards-Anderson model with an external magnetic field (HEA). We study the model with Monte Carlo (MC) simulations in the mean-field (MF) and non-mean-field (NMF) regions corresponding to d >= 4 and d < 4 for the d-dimensional ferromagnetic Ising model respectively. We compare the MC results with those of a renormalization-group (RG) study where the critical fixed point is treated as a perturbation of the MF one, along the same lines as in the -expansion for the Ising model. The MC and the RG method agree in the MF region, predicting the existence of a transition and compatible values of the critical exponents. Conversely, the two approaches markedly disagree in the NMF case, where the MC data indicates a transition, while the RG analysis predicts that no perturbative critical fixed point exists. Also, the MC estimate of the critical exponent ν in the NMF region is about twice as large as its classical value, even if the analog of the system dimension is within only ~2% from its upper-critical-dimension value. Taken together, these results indicate that the transition in the NMF region is governed by strong non-perturbative effects.

  4. Non-perturbative effects in spin glasses

    PubMed Central

    Castellana, Michele; Parisi, Giorgio

    2015-01-01

    We present a numerical study of an Ising spin glass with hierarchical interactions—the hierarchical Edwards-Anderson model with an external magnetic field (HEA). We study the model with Monte Carlo (MC) simulations in the mean-field (MF) and non-mean-field (NMF) regions corresponding to d ≥ 4 and d < 4 for the d-dimensional ferromagnetic Ising model respectively. We compare the MC results with those of a renormalization-group (RG) study where the critical fixed point is treated as a perturbation of the MF one, along the same lines as in the -expansion for the Ising model. The MC and the RG method agree in the MF region, predicting the existence of a transition and compatible values of the critical exponents. Conversely, the two approaches markedly disagree in the NMF case, where the MC data indicates a transition, while the RG analysis predicts that no perturbative critical fixed point exists. Also, the MC estimate of the critical exponent ν in the NMF region is about twice as large as its classical value, even if the analog of the system dimension is within only ~2% from its upper-critical-dimension value. Taken together, these results indicate that the transition in the NMF region is governed by strong non-perturbative effects. PMID:25733337

  5. Nonperturbative Renormalization Group Approach to Polymerized Membranes

    NASA Astrophysics Data System (ADS)

    Essafi, Karim; Kownacki, Jean-Philippe; Mouhanna, Dominique

    2014-03-01

    Membranes or membrane-like materials play an important role in many fields ranging from biology to physics. These systems form a very rich domain in statistical physics. The interplay between geometry and thermal fluctuations lead to exciting phases such flat, tubular and disordered flat phases. Roughly speaking, membranes can be divided into two group: fluid membranes in which the molecules are free to diffuse and thus no shear modulus. On the other hand, in polymerized membranes the connectivity is fixed which leads to elastic forces. This difference between fluid and polymerized membranes leads to a difference in their critical behaviour. For instance, fluid membranes are always crumpled, whereas polymerized membranes exhibit a phase transition between a crumpled phase and a flat phase. In this talk, I will focus only on polymerized phantom, i.e. non-self-avoiding, membranes. The critical behaviour of both isotropic and anisotropic polymerized membranes are studied using a nonperturbative renormalization group approach (NPRG). This allows for the investigation of the phase transitions and the low temperature flat phase in any internal dimension D and embedding d. Interestingly, graphene behaves just as a polymerized membrane in its flat phase.

  6. Asymptotically free scalar curvature-ghost coupling in quantum Einstein gravity

    SciTech Connect

    Eichhorn, Astrid; Gies, Holger; Scherer, Michael M.

    2009-11-15

    We consider the asymptotic-safety scenario for quantum gravity which constructs a nonperturbatively renormalizable quantum gravity theory with the help of the functional renormalization group (RG). We verify the existence of a non-Gaussian fixed point and include a running curvature-ghost coupling as a first step towards the flow of the ghost sector of the theory. We find that the scalar curvature-ghost coupling is asymptotically free and RG relevant in the ultraviolet. Most importantly, the property of asymptotic safety discovered so far within the Einstein-Hilbert truncation and beyond remains stable under the inclusion of the ghost flow.

  7. A nonperturbative parametrization and scenario for EFT renormalization

    NASA Astrophysics Data System (ADS)

    Yang, Ji-Feng

    2009-03-01

    We present a universal form of the T-matrices renormalized in nonperturbative regime and the ensuing notions and properties that fail conventional wisdoms. A universal scale is identified and shown to be renormalization group invariant. The effective range parameters are derived in a nonperturbative scenario with some new predictions within the realm of contact potentials. Some controversies are shown to be due to the failure of conventional wisdoms.

  8. Probing nonperturbative QED with optimally focused laser pulses.

    PubMed

    Gonoskov, A; Gonoskov, I; Harvey, C; Ilderton, A; Kim, A; Marklund, M; Mourou, G; Sergeev, A

    2013-08-09

    We study nonperturbative pair production in intense, focused laser fields called e-dipole pulses. We address the conditions required, such as the quality of the vacuum, for reaching high intensities without initiating beam-depleting cascades, the number of pairs which can be created, and experimental detection of the created pairs. We find that e-dipole pulses offer an optimal method of investigating nonperturbative QED.

  9. Nonperturbative embedding for highly nonlocal Hamiltonians

    NASA Astrophysics Data System (ADS)

    Subaşı, Yiǧit; Jarzynski, Christopher

    2016-07-01

    The need for Hamiltonians with many-body interactions arises in various applications of quantum computing. However, interactions beyond two-body are difficult to realize experimentally. Perturbative gadgets were introduced to obtain arbitrary many-body effective interactions using Hamiltonians with at most two-body interactions. Although valid for arbitrary k -body interactions, their use is limited to small k because the strength of interaction is k th order in perturbation theory. In this paper we develop a nonperturbative technique for obtaining effective k -body interactions using Hamiltonians consisting of at most l -body interactions with l

  10. Mechanism of RecQ helicase mechanoenzymatic coupling reveals that the DNA interactions of the ADP-bound enzyme control translocation run terminations.

    PubMed

    Sarlós, Kata; Gyimesi, Máté; Kele, Zoltán; Kovács, Mihály

    2015-01-01

    The processing of various DNA structures by RecQ helicases is crucial for genome maintenance in both bacteria and eukaryotes. RecQ helicases perform active destabilization of DNA duplexes, based on tight coupling of their ATPase activity to moderately processive translocation along DNA strands. Here, we determined the ATPase kinetic mechanism of E. coli RecQ helicase to reveal how mechanoenzymatic coupling is achieved. We found that the interaction of RecQ with DNA results in a drastic acceleration of the rate-limiting ATP cleavage step, which occurs productively due to subsequent rapid phosphate release. ADP release is not rate-limiting and ADP-bound RecQ molecules make up a small fraction during single-stranded DNA translocation. However, the relatively rapid release of the ADP-bound enzyme from DNA causes the majority of translocation run terminations (i.e. detachment from the DNA track). Thus, the DNA interactions of ADP-bound RecQ helicase, probably dependent on DNA structure, will mainly determine translocation processivity and may control the outcome of DNA processing. Comparison with human Bloom's syndrome (BLM) helicase reveals that similar macroscopic parameters are achieved by markedly different underlying mechanisms of RecQ homologs, suggesting diversity in enzymatic tuning.

  11. Backward running or absence of running from Creutz ratios

    SciTech Connect

    Giedt, Joel; Weinberg, Evan

    2011-10-01

    We extract the running coupling based on Creutz ratios in SU(2) lattice gauge theory with two Dirac fermions in the adjoint representation. Depending on how the extrapolation to zero fermion mass is performed, either backward running or an absence of running is observed at strong bare coupling. This behavior is consistent with other findings which indicate that this theory has an infrared fixed point.

  12. Nonperturbative multiphoton processes and electron-positron pair production

    SciTech Connect

    Hatsagortsyan, K. Z.; Mueller, C.; Keitel, C. H.

    2006-04-07

    Various regimes of pair production in laser fields are analyzed. Particularly, the question of the observability of pair production in a nonperturbative multiphoton regime is discussed. A simple heuristic method is employed which gives order-of-magnitude estimates for probabilities of multiphoton processes and allows to describe its main features. The method is initially probed upon the known process of pair production in a Coulomb and a strong laser field. Then it is applied to the nonperturbative multiphoton regime of the pair production process in a standing laser wave.

  13. Nonperturbative multiphoton processes and electron-positron pair production

    NASA Astrophysics Data System (ADS)

    Hatsagortsyan, K. Z.; Müller, C.; Keitel, C. H.

    2006-04-01

    Various regimes of pair production in laser fields are analyzed. Particularly, the question of the observability of pair production in a nonperturbative multiphoton regime is discussed. A simple heuristic method is employed which gives order-of-magnitude estimates for probabilities of multiphoton processes and allows to describe its main features. The method is initially probed upon the known process of pair production in a Coulomb and a strong laser field. Then it is applied to the nonperturbative multiphoton regime of the pair production process in a standing laser wave.

  14. Non-perturbative renormalization of lattice operators in coordinate space

    NASA Astrophysics Data System (ADS)

    Giménez, V.; Giusti, L.; Guerriero, S.; Lubicz, V.; Martinelli, G.; Petrarca, S.; Reyes, J.; Taglienti, B.; Trevigne, E.

    2004-09-01

    We present the first numerical implementation of a non-perturbative renormalization method for lattice operators, based on the study of correlation functions in coordinate space at short Euclidean distance. The method is applied to compute the renormalization constants of bilinear quark operators for the non-perturbative O (a)-improved Wilson action in the quenched approximation. The matching with perturbative schemes, such as MS bar, is computed at the next-to-leading order in continuum perturbation theory. A feasibility study of this technique with Neuberger fermions is also presented.

  15. Running Away

    MedlinePlus

    ... away or know someone who has. If Your Friend Wants to Run Away If your friend is thinking about running away, warn him or ... will be to survive on the streets. Your friend is probably scared and confused. Try to be ...

  16. Running Shoes.

    ERIC Educational Resources Information Center

    Connors, G. Patrick

    This guide explains the purpose of running shoes and provides tips for purchasing them. A brief explanation of the difference between training shoes and racing shoes is followed by a list of characteristics of running shoes that should be considered when buying them. These characteristics include heel fit, heel elevation and width, the inner and…

  17. Insights on non-perturbative aspects of TMDs from models

    SciTech Connect

    H. Avakian, A. Efremov, P. Schweitzer, O. Teryaev, F. Yuan, P. Zavada

    2009-12-01

    Transverse momentum dependent parton distribution functions are a key ingredient in the description of spin and azimuthal asymmetries in deep-inelastic scattering processes. Recent results from non-perturbative calculations in effective approaches are reviewed, with focus on relations among different parton distribution functions in QCD and models.

  18. A small cosmological constant due to non-perturbative quantum effects

    NASA Astrophysics Data System (ADS)

    Holland, Jan; Hollands, Stefan

    2014-06-01

    We propose an explanation for the ‘unnatural smallness’ of the cosmological constant, arguing that the stress-energy tensor of the Standard Model should be given by = ρvac ημν, with a vacuum energy ρvac that differs from the usual ‘dimensional analysis’ result by an exponentially small factor associated with non-perturbative effects. We substantiate our proposal by a rigorous analysis of a toy model, namely the two-dimensional Gross-Neveu model. The stress energy operator is constructed concretely via the operator-product-expansion, and the inherent ambiguities in its construction are carefully examined. Our result for the vacuum energy is then obtained from the assumptions that (a) the OPE-coefficients have an analytic dependence on g, which we propose to be a generic feature of QFT, and that (b) the vacuum energy vanishes to all orders in perturbation theory. Our result can also be interpreted as saying that, while the semi-classical Einstein’s equation can be fulfilled in Minkowski space at the perturbative level, it cannot at the non-perturbative level. Extrapolating our result from the Gross-Neveu model to the Standard Model, one would expect to find \\rho _vac\\sim \\Lambda ^4 e^{-O(1)/g^2}, where Λ is an energy scale such as Λ = MH, and g is a gauge coupling such as g2/4π = αEW. Assuming this extrapolation is justified, the exponentially small factor due to non-perturbative effects would explain why this quantity is tiny, instead of strictly zero.

  19. Emergent Gauge Fields and Their Nonperturbative Effects in Correlated Electrons

    NASA Astrophysics Data System (ADS)

    Kim, Ki-Seok; Tanaka, Akihiro

    The history of modern condensed matter physics may be regarded as the competition and reconciliation between Stoner's and Anderson's physical pictures, where the former is based on momentum-space descriptions focusing on long wave-length fluctuations while the latter is based on real-space physics emphasizing emergent localized excitations. In particular, these two view points compete with each other in various nonperturbative phenomena, which range from the problem of high Tc superconductivity, quantum spin liquids in organic materials and frustrated spin systems, heavy-fermion quantum criticality, metal-insulator transitions in correlated electron systems such as doped silicons and two-dimensional electron systems, the fractional quantum Hall effect, to the recently discussed Fe-based superconductors. An approach to reconcile these competing frameworks is to introduce topologically nontrivial excitations into the Stoner's description, which appear to be localized in either space or time and sometimes both, where scattering between itinerant electrons and topological excitations such as skyrmions, vortices, various forms of instantons, emergent magnetic monopoles, and etc. may catch nonperturbative local physics beyond the Stoner's paradigm. In this review article we discuss nonperturbative effects of topological excitations on dynamics of correlated electrons. First, we focus on the problem of scattering between itinerant fermions and topological excitations in antiferromagnetic doped Mott insulators, expected to be relevant for the pseudogap phase of high Tc cuprates. We propose that nonperturbative effects of topological excitations can be incorporated within the perturbative framework, where an enhanced global symmetry with a topological term plays an essential role. In the second part, we go on to discuss the subject of symmetry protected topological states in a largely similar light. While we do not introduce itinerant fermions here, the nonperturbative

  20. New Nonperturbative Methods in Quantum Field Theory: From Large-N Orbifold Equivalence to Bions and Resurgence

    NASA Astrophysics Data System (ADS)

    Dunne, Gerald V.; Ünsal, Mithat

    2016-10-01

    We present a broad conceptual introduction to some new ideas in nonperturbative quantum field theory (QFT) that have led to progress toward an understanding of quark confinement in gauge theories and, more broadly, toward a nonperturbative continuum definition of QFTs. We first present exact orbifold equivalences of supersymmetric and nonsupersymmetric QFTs in the large-N limit and exact equivalences of large-N theories in infinite volume to large-N theories in finite volume, or even at a single point. We discuss principles by which calculable QFTs are continuously connected to strong-coupling QFTs, allowing understanding of the physics of confinement or the absence thereof. We discuss the role of particular saddle solutions, termed bions, in weak-coupling calculable regimes. The properties of bions motivate an extension of semiclassical methods used to evaluate functional integrals to include families of complex saddles (Picard-Lefschetz theory). This analysis leads us to the resurgence program, which may provide a framework for combining divergent perturbation series with semiclassical instanton and bion/renormalon contributions. This program could provide a nonperturbative definition of the path integral.

  1. Perturbative and non-perturbative aspects of the two-dimensional string/Yang-Mills correspondence

    NASA Astrophysics Data System (ADS)

    Lelli, Simone; Maggiore, Michele; Rissone, Anna

    2003-04-01

    It is known that YM 2 with gauge group SU( N) is equivalent to a string theory with coupling gs=1/ N, order by order in the 1/ N expansion. We show how this result can be obtained from the bosonization of the fermionic formulation of YM 2, improving on results in the literature, and we examine a number of non-perturbative aspects of this string/YM correspondence. We find contributions to the YM 2 partition function of order exp{- kA/( πα' gs)} with k an integer and A the area of the target space, which would correspond, in the string interpretation, to D1-branes. Effects which could be interpreted as D0-branes are instead strictly absent, suggesting a non-perturbative structure typical of type 0B string theories. We discuss effects from the YM side that are interpreted in terms of the stringy exclusion principle of Maldacena and Strominger. We also find numerically an interesting phase structure, with a region where YM 2 is described by a perturbative string theory separated from a region where it is described by a topological string theory.

  2. Nonperturbative results for two-index conformal windows

    NASA Astrophysics Data System (ADS)

    Bergner, Georg; Ryttov, Thomas A.; Sannino, Francesco

    2015-12-01

    Via large and small N c relations we derive nonperturbative results about the conformal window of two-index theories. Using Schwinger-Dyson methods as well as four-loops results we estimate subleading corrections and show that naive large number of colors extrapolations are unreliable when N c is less than about six. Nevertheless useful nonper-turbative inequalities for the size of the conformal windows, for any number of colors, can be derived. By further observing that the adjoint conformal window is independent of the number of colors we argue, among other things, that: the large N c two-index conformal window is twice the conformal window of the adjoint representation (which can be determined at small N c) expressed in terms of Dirac fermions; lattice results for adjoint matter can be used to provide independent information on the conformal dynamics of two-index theories such as SU( N c) with two and four symmetric Dirac flavors.

  3. Nonperturbative equation of state of quark gluon plasma: Applications

    NASA Astrophysics Data System (ADS)

    Komarov, E. V.; Simonov, Yu. A.

    2008-05-01

    The vacuum-driven nonperturbative factors Li for quark and gluon Green's functions are shown to define the nonperturbative dynamics of QGP in the leading approximation. EoS obtained recently in the framework of this approach is compared in detail with known lattice data for μ = 0 including P/ T4, ɛ/ T4, {ɛ-3P}/{T4}. The basic role in the dynamics at T ≲ 3 Tc is played by the factors Li which are approximately equal to the modulus of Polyakov line for quark Lfund and gluon Ladj. The properties of Li are derived from field correlators and compared to lattice data, in particular the Casimir scaling property Ladj=(Lfund) follows in the Gaussian approximation valid for small vacuum correlation lengths. Resulting curves for P/ T4, ɛ/ T4, {ɛ-3P}/{T4} are in a reasonable agreement with lattice data, the remaining difference points out to an effective attraction among QGP constituents.

  4. Nonperturbative partonic quasidistributions of the pion from chiral quark models

    NASA Astrophysics Data System (ADS)

    Broniowski, Wojciech; Ruiz Arriola, Enrique

    2017-10-01

    We evaluate nonperturbatively the quark quasidistribution amplitude and the valence quark quasidistribution function of the pion in the framework of chiral quark models, namely the Nambu-Jona-Lasinio model and the Spectral Quark Model. We arrive at simple analytic expressions, where the nonperturbative dependence on the longitudinal momentum of the pion can be explicitly assessed. The model results for the quark quasidistribution amplitude of the pion compare favorably to the data obtained from the Euclidean lattice simulations. The quark distribution amplitude, arising in the limit of infinite longitudinal momentum of the pion, agrees, after suitable QCD evolution, to the recent data extracted from Euclidean lattices, as well as to the old data from transverse lattice simulations.

  5. Comparative study of nonperturbative heavy quarks in the nucleon

    NASA Astrophysics Data System (ADS)

    Hobbs, Timothy; Jimenez-Delgado, Pedro; Londergan, John; Melnitchouk, Wally

    2013-10-01

    We perform an analysis of the role of nonperturbative (or intrinsic) charm in the nucleon. Charm is generated nonperturbatively through Fock state expansions of the nucleon wave function to include five-quark virtual states involving charmed mesons and baryons. We consider contributions from a variety of charmed meson-baryon states and find surprisingly dominant effects from the D*0Λc+ configuration. Particular attention is paid to the existence and persistence of high- x structure for intrinsic charm, and the x dependence of the c - c asymmetry predicted in meson-baryon models. We also discuss efforts to constrain intrinsic charm via a forthcoming global QCD analysis, and the possibility of extracting intrinsic strangeness using a similar approach. Research supported by NSF grant NSF-PHY-1205019 and DOE Office of Science grants DE-FG02-87ER40365, DE-AC05-06OR23177.

  6. Nonperturbative studies in quantum field theory

    SciTech Connect

    Abada, A.

    1992-01-01

    This dissertation is composed of three different research topics. The first part deals with the Study of the so-called local lattice Yukawa theory. The motivation for this study is to investigate the interior of the phase diagram of this theory. A strong y expansion (y being the bare Yukawa coupling) is performed of the partition function and show that within the (finite) range of convergence of the series expansion, the lattice Yukawa theory is equivalent to a purely bosonic theory, with a shifted action. The author explicitly calculated the shifted action to the fourth order in 1/y and find that it is composed of competing interactions. This suggests that away from y = [infinity] towards the interior of the phase diagram, there is a more complicated ordering than simple ferromagnetic or antiferromagnetic. In the second part, the question is addressed of formation of bound states out of constituent fields in an exactly soluble theory, i.e. multifermion electro-dynamics in two space-time dimensions. The author exactly calculates the correlation function corresponding to a neutral composite fermion operator and discuss the pole structure of its Fourier transform. It does not exhibit a simple pole in p[sup 2], hence the corresponding neutral composite operator does not create an asymptotic state in the spectrum of the theory. In part three, the author puts multifermion QED[sub 2] in a heat bath and address the same question as in part two. The author first exactly calculates a bosonic correlation function at finite temperature and density, and discuss its behavior. The author then exactly calculates the correlation function corresponding to the neutral composite fermion operator at finite temperature and density and discusses its behavior. It is concluded that the temperature does not help the composite fermion operator create a particle in the spectrum of the theory.

  7. Nonperturbative theory of double photoionization of the hydrogen molecule

    SciTech Connect

    Vanroose, W.; Martin, F.; Rescigno, T.N.; McCurdy, C.W.

    2004-10-01

    We present completely ab initio nonperturbative calculations of the integral and single differential cross sections for double photoionization of H2 for photon energies from 53.9 to 75.7 eV. The method of exterior complex scaling, implemented with B-splines, is used to solve the Schrodinger equation for a correlated continuum wave function corresponding to a single photon having been absorbed by a correlated initial state. The results are in good agreement with experimental integral cross sections.

  8. Nonperturbative gluon and ghost propagators in d = 3

    SciTech Connect

    Papavassiliou, Joannis

    2011-05-23

    We study the nonperturbative gluon and ghost propagators in d = 3 Yang-Mills, using the Schwinger-Dyson equations of the pinch technique. The use of the Schwinger mechanism leads to the dynamical generation of a gluon mass, which, in turn, gives rise to an infrared finite gluon propagator and ghost dressing function. The propagators obtained are in very good agreement with the results of SU(2) lattice simulations.

  9. Non-perturbative inputs for gluon distributions in the hadrons

    NASA Astrophysics Data System (ADS)

    Ermolaev, B. I.; Troyan, S. I.

    2017-03-01

    Description of hadronic reactions at high energies is conventionally done in the framework of QCD factorization. All factorization convolutions comprise non-perturbative inputs mimicking non-perturbative contributions and perturbative evolution of those inputs. We construct inputs for the gluon-hadron scattering amplitudes in the forward kinematics and, using the optical theorem, convert them into inputs for gluon distributions in the hadrons, embracing the cases of polarized and unpolarized hadrons. In the first place, we formulate mathematical criteria which any model for the inputs should obey and then suggest a model satisfying those criteria. This model is based on a simple reasoning: after emitting an active parton off the hadron, the remaining set of spectators becomes unstable and therefore it can be described through factors of the resonance type, so we call it the resonance model. We use it to obtain non-perturbative inputs for gluon distributions in unpolarized and polarized hadrons for all available types of QCD factorization: basic, K_T-and collinear factorizations.

  10. Nonperturbative heavy-quark diffusion in the quark-gluon plasma.

    PubMed

    van Hees, H; Mannarelli, M; Greco, V; Rapp, R

    2008-05-16

    We evaluate heavy-quark (HQ) transport properties in a quark-gluon plasma (QGP) within a Brueckner many-body scheme employing interaction potentials extracted from thermal lattice QCD. The in-medium T matrices for elastic charm- and bottom-quark scattering off light quarks in the QGP are dominated by attractive meson and diquark channels which support resonance states up to temperatures of ~1.5T(c). The resulting drag coefficient increases with decreasing temperature, contrary to expectations based on perturbative QCD scattering. Employing relativistic Langevin simulations we compute HQ spectra and elliptic flow in sqrt[s(NN)]=200 GeV Au-Au collisions. A good agreement with electron decay data supports our nonperturbative computation of HQ diffusion, indicative for a strongly coupled QGP.

  11. Simulating compact quantum electrodynamics with ultracold atoms: probing confinement and nonperturbative effects.

    PubMed

    Zohar, Erez; Cirac, J Ignacio; Reznik, Benni

    2012-09-21

    Recently, there has been much interest in simulating quantum field theory effects of matter and gauge fields. In a recent work, a method for simulating compact quantum electrodynamics (CQED) using Bose-Einstein condensates has been suggested. We suggest an alternative approach, which relies on single atoms in an optical lattice, carrying 2l + 1 internal levels, which converges rapidly to CQED as l increases. That enables the simulation of CQED in 2 + 1 dimensions in both the weak and the strong coupling regimes, hence, allowing us to probe confinement as well as other nonperturbative effects of the theory. We provide an explicit construction for the case l = 1 which is sufficient for simulating the effect of confinement between two external static charges.

  12. Single-step de Sitter vacua from nonperturbative effects with matter

    NASA Astrophysics Data System (ADS)

    Guarino, Adolfo; Inverso, Gianluca

    2016-03-01

    A scenario of moduli stabilization based on the interplay between closed and open string sectors is explored in a bottom-up approach. We study N =1 effective supergravities inspired by type IIB orientifold constructions that include background fluxes and nonperturbative effects. The former generate the standard flux superpotential for the axiodilaton and complex structure moduli. The latter can be induced by gaugino condensation in a non-Abelian sector of D7-branes and involve the overall Kähler modulus of the compactification as well as matter fields. We analyze the dynamics of this coupled system and show that it is compatible with single-step moduli stabilization in a metastable de Sitter vacuum. A novelty of the scenario is that the F-term potential suffices to generate a positive cosmological constant and to stabilize all moduli, except for a flat direction that can be either lifted by a mass term or eaten up by an anomalous U(1).

  13. In situ non-perturbative temperature measurement in a Cs alkali laser.

    PubMed

    Shaffer, M K; Lilly, T C; Zhdanov, B V; Knize, R J

    2015-01-01

    The two-dimensional (2D) temperature profiles of an active-gain medium in a Cs + methane diode pumped alkali laser (DPAL) have been experimentally measured. This nonperturbative technique uses a Mach-Zehnder interferometer, which is longitudinally coupled into the cavity of an operating alkali laser to probe the distortion of the optical path length in the gain medium due to heating. The resulting interferograms are analyzed using the commercial program QuickFringe to quickly and accurately measure the distortion through which the temperature profile can be determined. For a 9 W Cs + methane DPAL being pumped with 20 W of resonant D2 light, a maximum temperature rise of 58°C is observed.

  14. Nonperturbative emergence of non-Fermi-liquid behavior in d =2 quantum critical metals

    NASA Astrophysics Data System (ADS)

    Meszena, Balazs; Säterskog, Petter; Bagrov, Andrey; Schalm, Koenraad

    2016-09-01

    We consider the planar local patch approximation of d =2 fermions at finite density coupled to a critical boson. In the quenched or Bloch-Nordsieck approximation, where one takes the limit of fermion flavors Nf→0 , the fermion spectral function can be determined exactly. We show that one can obtain this nonperturbative answer thanks to a specific identity of fermionic two-point functions in the planar local patch approximation. The resulting spectrum is that of a non-Fermi liquid: quasiparticles are not part of the exact fermionic excitation spectrum of the theory. Instead, one finds continuous spectral weight with power-law scaling excitations as in a d =1 dimensional critical state. Moreover, at low energies, there are three such excitations at three different Fermi surfaces, two with a low-energy Green's function G ˜(ω-v*k ) -1 /2 and one with G ˜|ω+k | -1 /3 .

  15. Diphoton excess in the 2HDM: Hastening towards instability and the nonperturbative regime

    NASA Astrophysics Data System (ADS)

    Bertuzzo, Enrico; Machado, Pedro A. N.; Taoso, Marco

    2016-12-01

    In December 2015, the ATLAS and CMS collaborations presented a possible signal in the diphoton channel. Although more data have shown that the signal was likely to be only a statistical fluctuation, it is interesting to ask what can be learned if any diphoton excess would show up in future data. Here we challenge the interpretation of any possible diphoton excess in a two-Higgs-doublet framework and find results that are valid whenever a large number of colored and charged vectorlike fermions are needed to boost the production cross section. In a broad region of parameter space, the one-loop effects of these fermions abruptly drive the scalar potential to instability even before the hypercharge gauge coupling becomes nonperturbative.

  16. COUPLING

    DOEpatents

    Frisch, E.; Johnson, C.G.

    1962-05-15

    A detachable coupling arrangement is described which provides for varying the length of the handle of a tool used in relatively narrow channels. The arrangement consists of mating the key and keyhole formations in the cooperating handle sections. (AEC)

  17. Nonperturbative renormalization group for scalar fields in de Sitter space: Beyond the local potential approximation

    NASA Astrophysics Data System (ADS)

    Guilleux, Maxime; Serreau, Julien

    2017-02-01

    Nonperturbative renormalization group techniques have recently proven a powerful tool to tackle the nontrivial infrared dynamics of light scalar fields in de Sitter space. In the present article, we develop the formalism beyond the local potential approximation employed in earlier works. In particular, we consider the derivative expansion, a systematic expansion in powers of field derivatives, appropriate for long wavelength modes, that we generalize to the relevant case of a curved metric with Lorentzian signature. The method is illustrated with a detailed discussion of the so-called local potential approximation prime which, on top of the full effective potential, includes a running (but field-independent) field renormalization. We explicitly compute the associated anomalous dimension for O (N ) theories. We find that it can take large values along the flow, leading to sizable differences as compared to the local potential approximation. However, it does not prevent the phenomenon of gravitationally induced dimensional reduction pointed out in previous studies. We show that, as a consequence, the effective potential at the end of the flow is unchanged as compared to the local potential approximation, the main effect of the running anomalous dimension being merely to slow down the flow. We discuss some consequences of these findings.

  18. Nonperturbative NN scattering in {sup 3}S{sub 1}–{sup 3}D{sub 1} channels of EFT(⁄π)

    SciTech Connect

    Yang, Ji-Feng

    2013-12-15

    The closed-form T matrices in the {sup 3}S{sub 1}–{sup 3}D{sub 1} channels of EFT(⁄π) for NN scattering with the potentials truncated at order O(Q{sup 4}) are presented with the nonperturbative divergences parametrized in a general manner. The stringent constraints imposed by the closed form of the T matrices are exploited in the underlying theory perspective and turned into virtues in the implementation of subtractions and the manifestation of power counting rules in nonperturbative regimes, leading us to the concept of EFT scenario. A number of scenarios of the EFT description of NN scattering are compared with PSA data in terms of effective range expansion and {sup 3}S{sub 1} phase shifts, showing that it is favorable to proceed in a scenario with conventional EFT couplings and sophisticated renormalization in order to have large NN scattering lengths. The informative utilities of fine tuning are demonstrated in several examples and naturally interpreted in the underlying theory perspective. In addition, some of the approaches adopted in the recent literature are also addressed in the light of EFT scenario. -- Highlights: •Closed-form unitary T matrices for NN scattering are obtained in EFT(⁄π). •Nonperturbative properties inherent in such closed-form T matrices are explored. •Nonperturbative renormalization is implemented through exploiting these properties. •Unconventional power counting of couplings is shown to be less favored by PSA data. •The ideas about nonperturbative renormalization here might have wider applications.

  19. Nonperturbative spin–boson and spin–spin dynamics and nonlinear Fano interferences: A unified dissipaton theory based study

    SciTech Connect

    Zhang, Hou-Dao; Xu, Rui-Xue Zheng, Xiao; Yan, YiJing

    2015-01-14

    We consider the hybrid system–bath dynamics, based on the Yan’s dissipaton formalism [Y. J. Yan, J. Chem. Phys. 140, 054105 (2014)]. This theory provides a unified quasi-particle treatment on three distinct classes of quantum bath, coupled nonperturbatively to arbitrary quantum systems. In this work, to study the entangled system and bath polarization and nonlinear Fano interference, we incorporate further the time-dependent light field, which interacts with both the molecular system and the collective bath dipoles directly. Numerical demonstrations are carried out on a two-level system, with comparison between phonon and exciton baths, in both linear and nonlinear Fano interference regimes.

  20. Non-perturbative QCD Modeling and Meson Physics

    SciTech Connect

    Nguyen, T.; Souchlas, N. A.; Tandy, P. C.

    2009-04-20

    Using a ladder-rainbow kernel previously established for light quark hadron physics, we explore the extension to masses and electroweak decay constants of ground state pseudoscalar and vector quarkonia and heavy-light mesons in the c- and b-quark regions. We make a systematic study of the effectiveness of a constituent mass concept as a replacement for a heavy quark dressed propagator for such states. The difference between vector and axial vector current correlators is explored within the same model to provide an estimate of the four quark chiral condensate and the leading distance scale for the onset of non-perturbative phenomena in QCD.

  1. Non-perturbative quantum gravity - A status report

    NASA Astrophysics Data System (ADS)

    Ashtekar, Abhay

    The status of a program to carry out an exact canonical quantization of gravity is summarized, focusing on the problem of nonperturbative quantization of general relativity. Consideration is given to the source-free Einsteing theory, the relation between Einstein's theory and Yang-Mills theory, and dynamics. Issues related to quantization are addressed, including the problem of finding exact solutions to quantum constraints, the conceptual structure of physics, and the problem of making phenomenological predictions that can be tested experimentally. Also, the problem of introducing suitable approximation methods is discussed.

  2. (Non)perturbative gravity, nonlocality, and nice slices

    SciTech Connect

    Giddings, Steven B.

    2006-11-15

    Perturbative dynamics of gravity is investigated for high-energy scattering and in black hole backgrounds. In the latter case, a straightforward perturbative analysis fails, in a close parallel to the failure of the former when the impact parameter reaches the Schwarzschild radius. This suggests a flaw in a semiclassical description of physics on spatial slices that intersect both outgoing Hawking radiation and matter that has carried information into a black hole; such slices are instrumental in a general argument for black hole information loss. This indicates a possible role for the proposal that nonperturbative gravitational physics is intrinsically nonlocal.

  3. Symmetries in non-perturbative 2-d quantum gravity

    SciTech Connect

    La, H. . Dept. of Physics)

    1991-03-07

    In this paper based on the Korteweg-de Vries (KdV) hierarchy formulation of non-perturbative 2-d quantum gravity, the authors investigate the symmetries of the system. Particularly, it is shown that the recently found Virasoro constraints are due to the non-isospectral symmetries of KdV hierarchy, which can be interpreted as SL(2, C) invariance and the independence of the moduli of the auxiliary infinite genus hyperelliptic Riemann surfaces which appear in the Krichever construction of soliton solutions.

  4. Nonperturbative parton distributions and the proton spin problem

    SciTech Connect

    Simonov, Yu. A.

    2016-05-15

    The Lorentz contracted form of the static wave functions is used to calculate the valence parton distributions for mesons and baryons, boosting the rest frame solutions of the path integral Hamiltonian. It is argued that nonperturbative parton densities are due to excitedmultigluon baryon states. A simplemodel is proposed for these states ensuring realistic behavior of valence and sea quarks and gluon parton densities at Q{sup 2} = 10 (GeV/c){sup 2}. Applying the same model to the proton spin problem one obtains Σ{sub 3} = 0.18 for the same Q{sup 2}.

  5. Comment on nonperturbative effects in B -> Xsγ

    NASA Astrophysics Data System (ADS)

    Ligeti, Zoltan; Randall, Lisa; Wise, Mark B.

    1997-02-01

    Uncertainties in the theoretical prediction for the inclusive B -> Xsγ decay rate are discussed. We emphasize that there is no operator product expansion for this process. Nonetheless, some nonperturbative effects involving a virtual c c loop are calculable using the operator product expansion. They give a contribution to the decay rate that involves the B meson matrix element of an infinite tower of operators. The higher dimension operators give effects that are only suppressed by powers of mbΛQCD/m2c ~ 0.6, but come with small coefficients.

  6. Uncovering nonperturbative dynamics of the biased sub-Ohmic spin-boson model with variational matrix product states

    NASA Astrophysics Data System (ADS)

    Gonzalez-Ballestero, C.; Schröder, Florian A. Y. N.; Chin, Alex W.

    2017-09-01

    We study the dynamics of the biased sub-Ohmic spin-boson model by means of a time-dependent variational matrix product state (TDVMPS) algorithm. The evolution of both the system and the environment is obtained in the weak- and the strong-coupling regimes, respectively characterized by damped spin oscillations and by a nonequilibrium process where the spin freezes near its initial state, which are explicitly shown to arise from a variety of reactive environmental quantum dynamics. We also explore the rich phenomenology of the intermediate-coupling case, a nonperturbative regime where the system shows a complex dynamical behavior, combining features of both the weakly and the strongly coupled case in a sequential, time-retarded fashion. Our work demonstrates the potential of TDVMPS methods for exploring otherwise elusive, nonperturbative regimes of complex open quantum systems, and points to the possibilities of exploiting the qualitative, real-time modification of quantum properties induced by nonequilibrium bath dynamics in ultrafast transient processes.

  7. Gaugino Condensation and Nonperturbative Superpotentials in F-Theory

    SciTech Connect

    Gorlich, L

    2004-08-05

    There are two known sources of nonperturbative superpotentials for Kahler moduli in type IIB orientifolds, or F-theory compactifications on Calabi-Yau fourfolds, with flux: Euclidean brane instantons and low-energy dynamics in D7 brane gauge theories. The first class of effects, Euclidean D3 branes which lift in M-theory to M5 branes wrapping divisors of arithmetic genus 1 in the fourfold, is relatively well understood. The second class has been less explored. In this paper, we consider the explicit example of F-theory on K3 x K3 with flux. The fluxes lift the D7 brane matter fields, and stabilize stacks of D7 branes at loci of enhanced gauge symmetry. The resulting theories exhibit gaugino condensation, and generate a nonperturbative superpotential for Kahler moduli. The authors describe how the relevant geometries in general contain cycles of arithmetic genus {chi} {ge} 1 (and how {chi} > 1 divisors can contribute to the superpotential, in the presence of flux). This second class of effects is likely to be important in finding even larger classes of models where the KKLT mechanism of moduli stabilization can be realized. They also address various claims about the situation for IIB models with a single Kahler modulus.

  8. Nonperturbative relativistic calculation of the muonic hydrogen spectrum

    SciTech Connect

    Carroll, J. D.; Thomas, A. W.; Rafelski, J.; Miller, G. A.

    2011-07-15

    We investigate the muonic hydrogen 2P{sub 3/2}{sup F=2} to 2S{sub 1/2}{sup F=1} transition through a precise, nonperturbative numerical solution of the Dirac equation including the finite-size Coulomb force and finite-size vacuum polarization. The results are compared with earlier perturbative calculations of (primarily) [E. Borie, Phys. Rev. A 71, 032508 (2005); E. Borie and G. A. Rinker, Rev. Mod. Phys. 54, 67 (1982); E. Borie, Z. Phys. A 275, 347 (1975) and A. P. Martynenko, Phys. Rev. A 71, 022506 (2005); A. Martynenko, Phys. At. Nucl. 71, 125 (2008), and K. Pachucki, Phys. Rev. A 53, 2092 (1996)] and experimental results recently presented by Pohl et al.[Nature (London) 466, 213 (2010)], in which this very comparison is interpreted as requiring a modification of the proton charge radius from that obtained in electron scattering and electronic hydrogen analyses. We find no significant discrepancy between the perturbative and nonperturbative calculations, and we present our results as confirmation of the perturbative methods.

  9. Quantum geometry of resurgent perturbative/nonperturbative relations

    DOE PAGES

    Basar, Gokce; Dunne, Gerald V.; Unsal, Mithat

    2017-05-16

    For a wide variety of quantum potentials, including the textbook ‘instanton’ examples of the periodic cosine and symmetric double-well potentials, the perturbative data coming from fluctuations about the vacuum saddle encodes all non-perturbative data in all higher non-perturbative sectors. Here we unify these examples in geometric terms, arguing that the all-orders quantum action determines the all-orders quantum dual action for quantum spectral problems associated with a classical genus one elliptic curve. Furthermore, for a special class of genus one potentials this relation is particularly simple: this class includes the cubic oscillator, symmetric double-well, symmetric degenerate triple-well, and periodic cosine potential.more » These are related to the Chebyshev potentials, which are in turn related to certain N = 2 supersymmetric quantum field theories, to mirror maps for hypersurfaces in projective spaces, and also to topological c = 3 Landau-Ginzburg models and ‘special geometry’. These systems inherit a natural modular structure corresponding to Ramanujan’s theory of elliptic functions in alternative bases, which is especially important for the quantization. Insights from supersymmetric quantum field theory suggest similar structures for more complicated potentials, corresponding to higher genus. Lastly, our approach is very elementary, using basic classical geometry combined with all-orders WKB.« less

  10. Quantum geometry of resurgent perturbative/nonperturbative relations

    NASA Astrophysics Data System (ADS)

    Basar, Gökçe; Dunne, Gerald V.; Ünsal, Mithat

    2017-05-01

    For a wide variety of quantum potentials, including the textbook `instanton' examples of the periodic cosine and symmetric double-well potentials, the perturbative data coming from fluctuations about the vacuum saddle encodes all non-perturbative data in all higher non-perturbative sectors. Here we unify these examples in geometric terms, arguing that the all-orders quantum action determines the all-orders quantum dual action for quantum spectral problems associated with a classical genus one elliptic curve. Furthermore, for a special class of genus one potentials this relation is particularly simple: this class includes the cubic oscillator, symmetric double-well, symmetric degenerate triple-well, and periodic cosine potential. These are related to the Chebyshev potentials, which are in turn related to certain \\mathcal{N} = 2 supersymmetric quantum field theories, to mirror maps for hypersurfaces in projective spaces, and also to topological c = 3 Landau-Ginzburg models and `special geometry'. These systems inherit a natural modular structure corresponding to Ramanujan's theory of elliptic functions in alternative bases, which is especially important for the quantization. Insights from supersymmetric quantum field theory suggest similar structures for more complicated potentials, corresponding to higher genus. Our approach is very elementary, using basic classical geometry combined with all-orders WKB.

  11. Perturbational and nonperturbational inversion of Rayleigh-wave velocities

    USGS Publications Warehouse

    Haney, Matt; Tsai, Victor C.

    2017-01-01

    The inversion of Rayleigh-wave dispersion curves is a classic geophysical inverse problem. We have developed a set of MATLAB codes that performs forward modeling and inversion of Rayleigh-wave phase or group velocity measurements. We describe two different methods of inversion: a perturbational method based on finite elements and a nonperturbational method based on the recently developed Dix-type relation for Rayleigh waves. In practice, the nonperturbational method can be used to provide a good starting model that can be iteratively improved with the perturbational method. Although the perturbational method is well-known, we solve the forward problem using an eigenvalue/eigenvector solver instead of the conventional approach of root finding. Features of the codes include the ability to handle any mix of phase or group velocity measurements, combinations of modes of any order, the presence of a surface water layer, computation of partial derivatives due to changes in material properties and layer boundaries, and the implementation of an automatic grid of layers that is optimally suited for the depth sensitivity of Rayleigh waves.

  12. Perturbational and Nonperturbational Inversion of Rayleigh-Wave Velocities

    NASA Astrophysics Data System (ADS)

    Haney, M. M.; Tsai, V. C.

    2016-12-01

    The inversion of Rayleigh-wave dispersion curves is a classic geophysical inverse problem. We describe a set of Matlab codes which performs both forward modeling and inversion of Rayleigh-wave phase or group velocity measurements. We present two different methods of inversion: a perturbational method based on finite elements and a nonperturbational method based on the recently developed Dix-type relation for Rayleigh waves. In practice, the nonperturbational method can be used to provide a good starting model that can be iteratively improved with the perturbational method. Although the perturbational method is well-known, we solve the forward problem using an eigenvalue/eigenvector solver instead of the conventional approach of root-finding. Features of the codes include the ability to handle any mix of phase or group velocity measurements, combinations of modes of any order, the presence of a surface water layer, computation of partial derivatives due to changes in both material properties and layer boundaries, and the implementation of an automatic grid of layers that is optimally suited for the depth sensitivity of Rayleigh waves.

  13. Testing QCD in the non-perturbative regime

    SciTech Connect

    A.W. Thomas

    2007-01-01

    This is an exciting time for strong interaction physics. We have a candidate for a fundamental theory, namely QCD, which has passed all the tests thrown at it in the perturbative regime. In the non-perturbative regime it has also produced some promising results and recently a few triumphs but the next decade will see enormous progress in our ability to unambiguously calculate the consequences of non-perturbative QCD and to test those predictions experimentally. Amongst the new experimental facilities being constructed, the hadronic machines at JPARC and GSI-FAIR and the 12 GeV Upgrade at Jefferson Lab, the major new electromagnetic facility worldwide, present a beautifully complementary network aimed at producing precise new measurements which will advance our knowledge of nuclear systems and push our ability to calculate the consequences of QCD to the limit. We will first outline the plans at Jefferson Lab for doubling the energy of CEBAF. The new facility presents some wonderful opportunities for discovery in strong interaction physics, as well as beyond the standard model. Then we turn to the theoretical developments aimed at extracting precise results for physical hadron properties from lattice QCD simulations. This discussion will begin with classical examples, such as the mass of the nucleon and ?, before dealing with a very recent and spectacular success involving information extracted from modern parity violating electron scattering.

  14. Resurgence in quantum field theory: nonperturbative effects in the principal chiral model.

    PubMed

    Cherman, Aleksey; Dorigoni, Daniele; Dunne, Gerald V; Ünsal, Mithat

    2014-01-17

    We explain the physical role of nonperturbative saddle points of path integrals in theories without instantons, using the example of the asymptotically free two-dimensional principal chiral model (PCM). Standard topological arguments based on homotopy considerations suggest no role for nonperturbative saddles in such theories. However, the resurgence theory, which unifies perturbative and nonperturbative physics, predicts the existence of several types of nonperturbative saddles associated with features of the large-order structure of the perturbation theory. These points are illustrated in the PCM, where we find new nonperturbative "fracton" saddle point field configurations, and suggest a quantum interpretation of previously discovered "uniton" unstable classical solutions. The fractons lead to a semiclassical realization of IR renormalons in the circle-compactified theory and yield the microscopic mechanism of the mass gap of the PCM.

  15. How nonperturbative is the infrared regime of Landau gauge Yang-Mills correlators?

    NASA Astrophysics Data System (ADS)

    Reinosa, U.; Serreau, J.; Tissier, M.; Wschebor, N.

    2017-07-01

    We study the Landau gauge correlators of Yang-Mills fields for infrared Euclidean momenta in the context of a massive extension of the Faddeev-Popov Lagrangian which, we argue, underlies a variety of continuum approaches. Standard (perturbative) renormalization group techniques with a specific, infrared-safe renormalization scheme produce so-called decoupling and scaling solutions for the ghost and gluon propagators, which correspond to nontrivial infrared fixed points. The decoupling fixed point is infrared stable and weakly coupled, while the scaling fixed point is unstable and generically strongly coupled except for low dimensions d →2 . Under the assumption that such a scaling fixed point exists beyond one-loop order, we find that the corresponding ghost and gluon scaling exponents are, respectively, 2 αF=2 -d and 2 αG=d at all orders of perturbation theory in the present renormalization scheme. We discuss the relation between the ghost wave function renormalization, the gluon screening mass, the scale of spectral positivity violation, and the gluon mass parameter. We also show that this scaling solution does not realize the standard Becchi-Rouet-Stora-Tyutin symmetry of the Faddeev-Popov Lagrangian. Finally, we discuss our findings in relation to the results of nonperturbative continuum methods.

  16. Toward the development of Raman spectroscopy as a nonperturbative online monitoring tool for gasoline adulteration.

    PubMed

    Tan, Khay M; Barman, Ishan; Dingari, Narahara C; Singh, Gajendra P; Chia, Tet F; Tok, Wee L

    2013-02-05

    There is a critical need for a real-time, nonperturbative probe for monitoring the adulteration of automotive gasoline. Running on adulterated fuel leads to a substantive increase in air pollution, because of increased tailpipe emissions of harmful pollutants, as well as a reduction in engine performance. Consequently, both classification of the gasoline type and quantification of the adulteration content are of great significance for quality control. Gasoline adulteration detection is currently carried out in the laboratory with gas chromatography, which is time-consuming and costly. Here, we propose the application of Raman spectroscopic measurements for on-site rapid detection of gasoline adulteration. In this proof-of-principle report, we demonstrate the effectiveness of Raman spectra, in conjunction with multivariate analysis methods, in classifying the base oil types and simultaneously detecting the adulteration content in a wide range of commercial gasoline mixtures, both in their native states and spiked with different adulterants. In particular, we show that Raman spectra acquired with an inexpensive noncooled detector provides adequate specificity to clearly discriminate between the gasoline samples and simultaneously characterize the specific adulterant content with a limit of detection below 5%. Our promising results in this study illustrate, for the first time, the capability and the potential of Raman spectroscopy, together with multivariate analysis, as a low-cost, powerful tool for on-site rapid detection of gasoline adulteration and opens substantive avenues for applications in related fields of quality control in the oil industry.

  17. Perturbation theory and nonperturbative effects: A happy marriage ?

    NASA Astrophysics Data System (ADS)

    Chýla, J.

    1992-03-01

    Perturbation expansions in renormalized quantum field theories are reformulated in a way that permits a straightforward handling of situations when in the conventional approach, i.e. in fixed renormalization scheme, these expansions are factorially divergent and even of asymptotically constant sign. The result takes the form of convergent (under certain circumstances) expansions in a set of functions Z k(a, χ) of the couplant and the free parameter χ which specifies the procedure involved. The value of χ is shown to be correlated to the basic properties of nonperturbative effects as embodied in power corrections. Close connection of this procedure to Borel summation technique is demonstrated and its relation to conventional perturbation theory in fixed renormalization schemes elucidated.

  18. A new non-perturbative time-dependent string configuration

    SciTech Connect

    Alexandre, Jean

    2007-11-20

    A time-dependent bosonic string configuration is discussed, in graviton and dilaton backgrounds, which leads to Weyl-symmetry beta-functions which are homogeneous in X{sup 0}, to any order in {alpha}{sup '}. As a consequence, a string reparametrization can always be implemented, such that beta functions can be cancelled, to any order in {alpha}{sup '}. This non-perturbative conformal invariance is valid for any target space dimension, and leads to a power law expanding Universe, for which the power vanishes if a specific relation between the dimension and dilaton amplitude holds. Finally, D = 4 is the minimum dimension (in the case of a spherical world sheet) for which this configuration is consistent with a Wick rotation in a Minkowski target space.

  19. Nonperturbative decay of udd and QLd flat directions

    NASA Astrophysics Data System (ADS)

    Gümrükçüoǧlu, A. Emir

    2009-12-01

    The minimal supersymmetric standard model has several flat directions, which can naturally be excited during inflation. If they have a slow (perturbative) decay, they may affect the thermalization of the inflaton decay products. In the present paper, we consider the system of udd and QLd flat directions, which breaks the U(1)×SU(2)×SU(3) symmetry completely. In the unitary gauge and assuming a general soft breaking mass configuration, we show that for a range of parameters, the background condensate of flat directions can undergo a fast nonperturbative decay, due to nonadiabatic evolution of the eigenstates. We find that both the background evolution and part of the decay can be described accurately by previously studied gauged toy models of flat direction decay.

  20. Nonperturbative structure of the photon and gluon propagators

    NASA Astrophysics Data System (ADS)

    Lowdon, Peter

    2017-09-01

    The nonperturbative structure of the photon and gluon propagators plays an important role in governing the dynamics of quantum electrodynamics (QED) and quantum chromodynamics (QCD), respectively. Although it is often assumed that these interacting field propagators can be decomposed into longitudinal and transverse components, as for the free case, it turns out that in general this is not possible. Moreover, the non-Abelian gauge symmetry of QCD permits the momentum space gluon propagator to contain additional singular terms involving derivatives of δ (p ), the appearance of which is related to confinement. Despite the possibility of the failure of the transverse-longitudinal decomposition for the photon and gluon propagators, and the appearance of singular terms in the gluon propagator, the Slavnov-Taylor identity nevertheless remains preserved.

  1. Nonperturbative True Muonium on the Light Front with TMSWIFT

    NASA Astrophysics Data System (ADS)

    Lamm, Henry; Lebed, Richard F.

    2016-08-01

    The true muonium {(μbar{μ})} bound state presents an interesting test of light-cone quantization techniques. In addition to exhibiting the standard problems of handling non-perturbative calculations, true muonium requires correct treatment of {ebar{e}} Fock-state contributions. Having previously produced a crude model of true muonium using the method of iterated resolvents, our current work has focused on the inclusion of the box diagrams to improve the cutoff-dependent issues of the model. Further, a parallel computer code, TMSWIFT, allowing for smaller numerical uncertainties, has been developed. This work focuses on the current state of these efforts to develop a model of true muonium that is testable at near-term experiments.

  2. Nonperturbative dynamics of reheating after inflation: A review

    NASA Astrophysics Data System (ADS)

    Amin, Mustafa A.; Hertzberg, Mark P.; Kaiser, David I.; Karouby, Johanna

    2015-12-01

    Our understanding of the state of the universe between the end of inflation and big bang nucleosynthesis (BBN) is incomplete. The dynamics at the end of inflation are rich and a potential source of observational signatures. Reheating, the energy transfer between the inflaton and Standard Model fields (possibly through intermediaries) and their subsequent thermalization, can provide clues to how inflation fits in with known high-energy physics. We provide an overview of our current understanding of the nonperturbative, nonlinear dynamics at the end of inflation, some salient features of realistic particle physics models of reheating, and how the universe reaches a thermal state before BBN. In addition, we review the analytical and numerical tools available in the literature to study preheating and reheating and discuss potential observational signatures from this fascinating era.

  3. Nonlinear normal modes in electrodynamic systems: A nonperturbative approach

    SciTech Connect

    Kudrin, A. V. Kudrina, O. A.; Petrov, E. Yu.

    2016-06-15

    We consider electromagnetic nonlinear normal modes in cylindrical cavity resonators filled with a nonlinear nondispersive medium. The key feature of the analysis is that exact analytic solutions of the nonlinear field equations are employed to study the mode properties in detail. Based on such a nonperturbative approach, we rigorously prove that the total energy of free nonlinear oscillations in a distributed conservative system, such as that considered in our work, can exactly coincide with the sum of energies of the normal modes of the system. This fact implies that the energy orthogonality property, which has so far been known to hold only for linear oscillations and fields, can also be observed in a nonlinear oscillatory system.

  4. Nonperturbative Dynamics of Strong Interactions from Gauge/Gravity Duality

    SciTech Connect

    Grigoryan, Hovhannes

    2008-08-01

    This thesis studies important dynamical observables of strong interactions such as form factors. It is known that Quantum Chromodynamics (QCD) is a theory which describes strong interactions. For large energies, one can apply perturbative techniques to solve some of the QCD problems. However, for low energies QCD enters into the nonperturbative regime, where di erent analytical or numerical tools have to be applied to solve problems of strong interactions. The holographic dual model of QCD is such an analytical tool that allows one to solve some nonperturbative QCD problems by translating them into a dual ve-dimensional theory de ned on some warped Anti de Sitter (AdS) background. Working within the framework of the holographic dual model of QCD, we develop a formalism to calculate form factors and wave functions of vector mesons and pions. As a result, we provide predictions of the electric radius, the magnetic and quadrupole moments which can be directly veri ed in lattice calculations or even experimentally. To nd the anomalous pion form factor, we propose an extension of the holographic model by including the Chern-Simons term required to reproduce the chiral anomaly of QCD. This allows us to nd the slope of the form factor with one real and one slightly o -shell photon which appeared to be close to the experimental ndings. We also analyze the limit of large virtualities (when the photon is far o -shell) and establish that predictions of the holographic model analytically coincide with those of perturbative QCD with asymptotic pion distribution amplitude. We also study the e ects of higher dimensional terms in the AdS/QCD model and show that these terms improve the holographic description towards a more realistic scenario. We show this by calculating corrections to the vector meson form factors and corrections to the observables such as electric radii, magnetic and quadrupole moments.

  5. Perturbative and nonperturbative aspects of heterotic sigma models

    NASA Astrophysics Data System (ADS)

    Cui, Xiaoyi

    Supersymmetric nonlinear sigma models are interesting from various perspectives. They are useful for understanding the most fundamental theory of our world, and for low-energy effective model-building. Mathematically, they make surprising connections between different exciting areas such as complex geometry, deformation theory, quantum algebra and topology. In this thesis, we study perturbative and nonperturbative aspects of sigma models with N = (0, 2) supersymmetry, with an emphasize on a possible version of extended 4d/2d correspondence. We showed that in some N = (0, 2) models, β functions calculated through Feynman graphs can be reproduced by nonrenormalization theorems. And the result can further be compared with the supercurrent analysis. These cases including linear models, minimal CP(1) model (other CP(N) models are obstructed by global anomaly) together with its extended cousins, and heterotic CP(N) models. Nonperturbatively we built the instanton measure for minimal CP(1) model and its (0, 2)-extended cousins. The instanton measure bears similarity to the instanton measure for 4d super-Yang-Mills theories. Through this analogy, there seems to be a correspondence between N = 1 theories in 4d and N = (0, 2) theories in 2d, which extends previous results initiated by Edalati-Tong and Shifman-Yung. An interesting by-product is also obtained during the procedure, which shows that for non-minimal (globally anomaly-free) N = (0, 2) models with CP(1) as target spaces, there seems always exist certain infrared fixed points, induced by the behavior of chiral fermions.

  6. Energy evolution of the moments of the hadron distribution in QCD jets including NNLL resummation and NLO running-coupling corrections

    NASA Astrophysics Data System (ADS)

    Pérez-Ramos, Redamy; d'Enterria, David

    2014-08-01

    The moments of the single inclusive momentum distribution of hadrons in QCD jets, are studied in the next-to-modified-leading-log approximation (NMLLA) including next-to-leading-order (NLO) corrections to the αs strong coupling. The evolution equations are solved using a distorted Gaussian parametrisation, which successfully reproduces the spectrum of charged hadrons of jets measured in e + e - collisions. The energy dependencies of the maximum peak, multiplicity, width, kurtosis and skewness of the jet hadron distribution are computed analytically. Comparisons of all the existing jet data measured in e + e - collisions in the range GeV to the NMLLA + NLO* predictions allow one to extract a value of the QCD parameter ΛQCD , and associated two-loop coupling constant at the Z resonance α s(m{Z/2}) = 0.1195 ± 0.0022, in excellent numerical agreement with the current world average obtained using other methods.

  7. Renormalization group and Pade applications to perturbative and non-perturbative quantum field theory

    NASA Astrophysics Data System (ADS)

    Chishtie, Farrukh Ahmed

    Pade approximants (PA) have been widely applied in practically all areas of physics. This thesis focuses on developing PA as tools for both perturbative and non-perturbative quantum field theory (QFT). In perturbative QFT, we systematically estimate higher (unknown) loop terms via the asymptotic formula devised by Samuel et al. This algorithm, generally denoted as the asymptotic Pade approximation procedure (APAP), has greatly enhanced scope when it is applied to renormalization-group-(RG-) invariant quantities. A presently-unknown higher-loop quantity can then be matched with the approximant over the entire momentum region of phenomenological interest. Furthermore, the predicted value of the RG coefficients can be compared with the RG-accessible coefficients (at the higher-loop order), allowing a clearer indication of the accuracy of the predicted RG-inaccessible term. This methodology is applied to hadronic Higgs decay rates (H → bb¯ and H → gg, both within the Standard Model and its MSSM extension), Higgs-sector cross-sections ( W+LW- L→ZL ZL ), inclusive semileptonic b → u decays (leading to reduced theoretical uncertainties in the extraction of |Vub|), QCD (Quantum Chromodynamics) correlation functions (scalar-fermionic, scalar-gluonic and vector correlators) and the QCD static potential. APAP is also applied directly to RG beta- and gamma-functions in massive φ4 theory. In non-perturbative QFT we use Pade summation methods to probe the large coupling regions of QCD. In analysing all the possible Pade-approximants to truncated beta-function for QCD, we are able to probe the singularity structure corresponding to the all orders beta-function. Noting the consistent ordering of poles and roots for such approximants (regardless of the next unknown higher-loop contribution), we conclude that these approximants are free of defective (pole) behaviour and hence we can safely draw physical conclusions from them. QCD is shown to have a flavour threshold (6

  8. Arterial wave intensity and ventricular-arterial coupling by vascular ultrasound: rationale and methods for the automated analysis of forwards and backwards running waves.

    PubMed

    Rakebrandt, F; Palombo, C; Swampillai, J; Schön, F; Donald, A; Kozàkovà, M; Kato, K; Fraser, A G

    2009-02-01

    Wave intensity (WI) in the circulation is estimated noninvasively as the product of instantaneous changes in pressure and velocity. We recorded diameter as a surrogate for pressure, and velocity in the right common carotid artery using an Aloka SSD-5500 ultrasound scanner. We developed automated software, applying the water hammer equation to obtain local wave speed from the slope of a pressure/velocity loop during early systole to separate net WI into individual forwards and backwards-running waves. A quality index was developed to test for noisy data. The timing, duration, peak amplitude and net energy of separated WI components were measured in healthy subjects with a wide age range. Age and arterial stiffness were independent predictors of local wave speed, whereas backwards-travelling waves correlated more strongly with ventricular systolic function than with age-related changes in arterial stiffness. Separated WI offers detailed insight into ventricular-arterial interactions that may be useful for assessing the relative contributions of ventricular and vascular function to wave travel.

  9. Nonperturbative NN scattering in 3S1-3D1 channels of EFT(⁄π)

    NASA Astrophysics Data System (ADS)

    Yang, Ji-Feng

    2013-12-01

    The closed-form T matrices in the 3S1-3D1 channels of EFT(⁄π) for NN scattering with the potentials truncated at order O(Q4) are presented with the nonperturbative divergences parametrized in a general manner. The stringent constraints imposed by the closed form of the T matrices are exploited in the underlying theory perspective and turned into virtues in the implementation of subtractions and the manifestation of power counting rules in nonperturbative regimes, leading us to the concept of EFT scenario. A number of scenarios of the EFT description of NN scattering are compared with PSA data in terms of effective range expansion and 3S1 phase shifts, showing that it is favorable to proceed in a scenario with conventional EFT couplings and sophisticated renormalization in order to have large NN scattering lengths. The informative utilities of fine tuning are demonstrated in several examples and naturally interpreted in the underlying theory perspective. In addition, some of the approaches adopted in the recent literature are also addressed in the light of EFT scenario.

  10. Building a non-perturbative quark-gluon vertex from a perturbative one

    NASA Astrophysics Data System (ADS)

    Bermudez, Rocio

    2016-10-01

    The quark-gluon vertex describes the electromagnetic and the strong interaction among these particles. The description of this interaction at high precision in both regimes, perturbative and non-perturbative, continues being a matter of interest in the context of QCD and Hadron Physics. There exist very helpful models in the literature that explain perturbative aspects of the theory but they fail describing non-perturbative phenomena, as confinement and dynamic chiral symmetry breaking. In this work we study the structure of the quark-gluon vertex in a non-perturbative regime examining QCD, checking results with QED, and working in the Schwinger-Dyson formalism.

  11. Nonperturbative Treatment of Electron-Impact Ionization of Ar(3p)

    NASA Astrophysics Data System (ADS)

    Bartschat, Klaus; Zatsarinny, Oleg

    2012-06-01

    We present triple-differential cross sections for electron-impact ionization of a 3p electron in Ar. Results from a fully non-perturbative close-coupling formalism using our B-Spline R-matrix with Pseudo-States (BSRMPS) approach [1] are compared with those from a hybrid distorted-wave plus R-matrix expansion [2] as well as recent experimental data [3]. We find overall good agreement between the two sets of entirely independent theoretical predictions, but serious discrepancies with the published experimental data. A detailed investigation of the dependence of the results on the fixed detection angle of the ``scattered projectile'', i.e., the faster of the two outgoing electrons, suggests that obtaining reliable results, both experimentally and theoretically, is highly challenging in the regime where the largest discrepancies occur. Consequently, care should be taken before much weight is put on the remaining deviations between experiment and theory. Further independent tests seem highly desirable.[4pt] [1] O. Zatsarinny and K. Bartschat, Phys. Rev. Lett. 107 (2011) 023203.[0pt] [2] K. Bartschat and O. K. Vorov, Phys. Rev. A 72 (2005) 022728.[0pt] [3] X. Ren, A. Senftleben, T. Pfl"uger, A. Dorn, K. Bartschat, and J. Ullrich, Phys. Rev. A 83 (2011) 052714.

  12. Nonperturbative renormalization group for the Kardar-Parisi-Zhang equation: general framework and first applications.

    PubMed

    Canet, Léonie; Chaté, Hugues; Delamotte, Bertrand; Wschebor, Nicolás

    2011-12-01

    We present an analytical method, rooted in the nonperturbative renormalization group, that allows one to calculate the critical exponents and the correlation and response functions of the Kardar-Parisi-Zhang (KPZ) growth equation in all its different regimes, including the strong-coupling one. We analyze the symmetries of the KPZ problem and derive an approximation scheme that satisfies the linearly realized ones. We implement this scheme at the minimal order in the response field, and show that it yields a complete, qualitatively correct phase diagram in all dimensions, with reasonable values for the critical exponents in physical dimensions. We also compute in one dimension the full (momentum and frequency dependent) correlation function, and the associated universal scaling function. We find a very satisfactory quantitative agreement with the exact result from Prähofer and Spohn [J. Stat. Phys. 115, 255 (2004)]. In particular, we obtain for the universal amplitude ratio g_{0}≃1.149(18), to be compared with the exact value g_{0}=1.1504... (the Baik and Rain [J. Stat. Phys. 100, 523 (2000)] constant). We emphasize that all these results, which can be systematically improved, are obtained with sole input the bare action and its symmetries, without further assumptions on the existence of scaling or on the form of the scaling function.

  13. Nonperturbative renormalization group for the diffusive epidemic process

    NASA Astrophysics Data System (ADS)

    Tarpin, Malo; Benitez, Federico; Canet, Léonie; Wschebor, Nicolás

    2017-08-01

    We consider the Diffusive Epidemic Process (DEP), a two-species reaction-diffusion process originally proposed to model disease spread within a population. This model exhibits a phase transition from an active epidemic to an absorbing state without sick individuals. Field-theoretic analyses suggest that this transition belongs to the universality class of Directed Percolation with a Conserved quantity (DP-C, not to be confused with conserved-directed percolation C-DP, appearing in the study of stochastic sandpiles). However, some exact predictions derived from the symmetries of DP-C seem to be in contradiction with lattice simulations. Here we revisit the field theory of both DP-C and DEP. We discuss in detail the symmetries present in the various formulations of both models. We then investigate the DP-C model using the derivative expansion of the nonperturbative renormalization group formalism. We recover previous results for DP-C near its upper critical dimension dc=4 , but show how the corresponding fixed point seems to no longer exist below d ≲3 . Consequences for the DEP universality class are considered.

  14. Nonperturbative production of matter and rapid thermalization after MSSM inflation

    NASA Astrophysics Data System (ADS)

    Allahverdi, Rouzbeh; Ferrantelli, Andrea; Garcia-Bellido, Juan; Mazumdar, Anupam

    2011-06-01

    A gauge invariant combination of LLe sleptons within the minimal supersymmetric standard model is one of the few inflaton candidates that can naturally explain population of the observable sector and creation of matter after inflation. After the end of inflation, the inflaton oscillates coherently about the minimum of its potential, which is a point of enhanced gauged symmetry. This results in bursts of nonperturbative production of the gauge/gaugino and (s)lepton quanta. The subsequent decay of these quanta is very fast and leads to an extremely efficient transfer of the inflaton energy to (s)quarks via instant preheating. Around 20% of the inflaton energy density is drained during every inflaton oscillation. However, all of the standard model degrees of freedom (and their supersymmetric partners) do not thermalize immediately, since the large inflaton vacuum expectation value breaks the electroweak symmetry. After about 100 oscillations—albeit within one Hubble time—the amplitude of inflaton oscillations becomes sufficiently small, and all of the degrees of freedom will thermalize. This provides by far the most efficient reheating of the universe with the observed degrees of freedom.

  15. Nonperturbative Renormalization of Composite Operators with Overlap Fermions

    SciTech Connect

    J.B. Zhang; N. Mathur; S.J. Dong; T. Draper; I. Horvath; F. X. Lee; D.B. Leinweber; K.F. Liu; A.G. Williams

    2005-12-01

    We compute non-perturbatively the renormalization constants of composite operators on a quenched 16{sup 3} x 28 lattice with lattice spacing a = 0.20 fm for the overlap fermion by using the regularization independent (RI) scheme. The quenched gauge configurations were generated with the Iwasaki action. We test the relations Z{sub A} = Z{sub V} and Z{sub S} = Z{sub P} and find that they agree well (less than 1%) above {mu} = 1.6 GeV. We also perform a Renormalization Group (RG) analysis at the next-to-next-to-leading order and match the renormalization constants to the {ovr MS} scheme. The wave-function renormalization Z{sub {psi}} is determined from the vertex function of the axial current and Z{sub A} from the chiral Ward identity. Finally, we examine the finite quark mass behavior for the renormalization factors of the quark bilinear operators. We find that the (pa){sup 2} errors of the vertex functions are small and the quark mass dependence of the renormalization factors to be quite weak.

  16. Nonperturbative results for the mass dependence of the QED fermion determinant

    SciTech Connect

    Fry, M. P.

    2010-05-15

    The fermion determinant in four-dimensional quantum electrodynamics in the presence of O(2)xO(3) symmetric background gauge fields with a nonvanishing global chiral anomaly is considered. It is shown that the leading mass singularity of the determinant's nonperturbative part is fixed by the anomaly. It is also shown that for a large class of such fields there is at least one value of the fermion mass at which the determinant's nonperturbative part reduces to its noninteracting value.

  17. On the nonperturbative theory of pure dephasing in condensed phases at low temperatures

    NASA Astrophysics Data System (ADS)

    Reichman, David; Silbey, Robert J.; Suárez, Alberto

    1996-12-01

    The nonperturbative treatment of the pure dephasing problem studied by Osad'ko and Skinner and Hsu is reexamined. It is found that these treatments are inadequate for very low temperatures in the case of Ohmic friction. New nonperturbative methods are used to expose interesting pure dephasing behavior at very low temperatures in this case. The methods are shown to coincide with the previous theories at higher temperatures. The experimental detection of such phenomena is discussed.

  18. Charmed spectroscopy from a nonperturbatively determined relativistic heavy quark action in full QCD

    SciTech Connect

    Huey-Wen Lin

    2006-07-28

    We present a preliminary calculation of the charmed meson spectrum using the 2+1 flavor domain wall fermion lattice configurations currently being generated by the RBC and UKQCD collaborations. The calculation is performed using the 3-parameter, relativistic heavy quark action with nonperturbatively determined coefficients. We will also demonstrate a step-scaling procedure for determining these coefficients nonperturbatively using a series of quenched, gauge field ensembles generated for three different lattice spacings.

  19. Changes in running economy following downhill running.

    PubMed

    Chen, Trevor C; Nosaka, Kazunori; Tu, Jui-Hung

    2007-01-01

    In this study, we examined the time course of changes in running economy following a 30-min downhill (-15%) run at 70% peak aerobic power (VO2peak). Ten young men performed level running at 65, 75, and 85% VO2peak (5 min for each intensity) before, immediately after, and 1 - 5 days after the downhill run, at which times oxygen consumption (VO2), minute ventilation, the respiratory exchange ratio (RER), heart rate, ratings of perceived exertion (RPE), and blood lactate concentration were measured. Stride length, stride frequency, and range of motion of the ankle, knee, and hip joints during the level runs were analysed using high-speed (120-Hz) video images. Downhill running induced reductions (7 - 21%, P < 0.05) in maximal isometric strength of the knee extensors, three- to six-fold increases in plasma creatine kinase activity and myoglobin concentration, and muscle soreness for 4 days after the downhill run. Oxygen consumption increased (4 - 7%, P < 0.05) immediately to 3 days after downhill running. There were also increases (P < 0.05) in heart rate, minute ventilation, RER, RPE, blood lactate concentration, and stride frequency, as well as reductions in stride length and range of motion of the ankle and knee. The results suggest that changes in running form and compromised muscle function due to muscle damage contribute to the reduction in running economy for 3 days after downhill running.

  20. Non-perturbative renormalization group calculation of the quasi-particle velocity and the dielectric function of graphene

    NASA Astrophysics Data System (ADS)

    Sharma, Anand; Bauer, Carsten; Rueckriegel, Andreas; Kopietz, Peter

    We use a nonperturbative functional renormalization group approach to calculate the renormalized quasiparticle velocity v (k) and the static dielectric function ɛ (k) of suspended graphene as function of an external momentum k. We fit our numerical result for v (k) to v (k) /vF = A + Bln (Λ0 / k) , where vF is the bare Fermi velocity, Λ0 is an ultraviolet cutoff, and A = 1 . 37 , B = 0 . 51 for the physically relevant value (e2 /vF = 2 . 2) of the coupling constant. In stark contrast to calculations based on the static random-phase approximation, we find that ɛ (k) approaches unity for k --> 0 . Our result for v (k) agrees very well with a recent measurement by Elias etal. [Nat. Phys. 7, 701 (2011)]. With in the same approximation, we also explore an alternative scheme in order to understand the true nature of the low energy (momentum) behavior in graphene.

  1. Nonperturbative effects on the ferromagnetic transition in repulsive Fermi gases

    NASA Astrophysics Data System (ADS)

    He, Lianyi; Huang, Xu-Guang

    2012-04-01

    It is generally believed that a dilute spin-(1)/(2) Fermi gas with repulsive interactions can undergo a ferromagnetic phase transition to a spin-polarized state at a critical gas parameter (kFa)c. Previous theoretical predictions of the ferromagnetic phase transition have been based on the perturbation theory, which treats the gas parameter as a small number. On the other hand, Belitz, Kirkpatrick, and Vojta (BKV) have argued that the phase transition in clean itinerant ferromagnets is generically of first order at low temperatures, due to the correlation effects that lead to a nonanalytic term in the free energy. The second-order perturbation theory predicts a first-order phase transition at (kFa)c=1.054, consistent with the BKV argument. However, since the critical gas parameter is expected to be of order O(1), perturbative predictions may be unreliable. In this paper we study the nonperturbative effects on the ferromagnetic phase transition by summing the particle-particle ladder diagrams to all orders in the gas parameter. We consider a universal repulsive Fermi gas where the effective range effects can be neglected, which can be realized in a two-component Fermi gas of 6Li atoms by using a nonadiabatic field switch to the upper branch of a Feshbach resonance with a positive s-wave scattering length. Our theory predicts a second-order phase transition, which indicates that ferromagnetic transition in dilute Fermi gases is possibly a counterexample to the BKV argument. The predicted critical gas parameter (kFa)c=0.858 is in good agreement with the recent quantum Monte Carlo result (kFa)c=0.86 for a nearly zero-range potential [S. Pilati , Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.105.030405 105, 030405 (2010)]. We also compare the spin susceptibility with the quantum Monte Carlo result and find good agreement.

  2. Problems at the interface between perturbative and nonperturbative quantum chromodynamics

    SciTech Connect

    Brodsky, S.J.; Bodwin, G.T.; Lepage, G.P.

    1983-06-01

    Predictions based on perturbative QCD rest on three premises: (1) that hadronic interactions become weak in strength at small invariant separation; (2) that the perturbative expansion in ..cap alpha../sub s/(Q) is well-defined; and (3) factorization: all effects of collinear singularities, confinement, nonperturbative interactions, and bound state dynamics can be isolated at large momentum transfer in terms of structure functions, fragmentation functions, or in the case of exclusive processes, distribution amplitudes. The assumption that the perturbative expansion for hard scattering amplitudes converges has certainly not been demonstrated; in addition, there are serious ambiguities concerning the choice of renormalization scheme and scale choice Q/sup 2/ for the expansion in ..cap alpha../sub s/(Q/sup 2/). We will discuss a new procedure to at least partly rectify the latter problem. In the case of exclusive processes, the factorization of hadronic amplitudes at large momentum transfer in the form of distribution amplitudes convoluted with hard scattering quark-gluon subprocess amplitudes can be demonstrated systematically to all orders in ..cap alpha../sub s/(Q/sup 2/). In the case of inclusive reactions, factorization remains an ansatz; general all-orders proofs do not exist because of the complications of soft initial state interactions for hadron-induced processes; thus far factorization has only been verified to two loops beyond lowest order in a regime where the applicability of perturbation theory is in doubt. However, we shall show that a necessary condition for the validity of factorization in inclusive reactions is that the momentum transfer must be large compared to the (rest frame) length of the target. We review the present status of the factorization ansatz. 52 references.

  3. Fatigue associated with prolonged graded running.

    PubMed

    Giandolini, Marlene; Vernillo, Gianluca; Samozino, Pierre; Horvais, Nicolas; Edwards, W Brent; Morin, Jean-Benoît; Millet, Guillaume Y

    2016-10-01

    Scientific experiments on running mainly consider level running. However, the magnitude and etiology of fatigue depend on the exercise under consideration, particularly the predominant type of contraction, which differs between level, uphill, and downhill running. The purpose of this review is to comprehensively summarize the neurophysiological and biomechanical changes due to fatigue in graded running. When comparing prolonged hilly running (i.e., a combination of uphill and downhill running) to level running, it is found that (1) the general shape of the neuromuscular fatigue-exercise duration curve as well as the etiology of fatigue in knee extensor and plantar flexor muscles are similar and (2) the biomechanical consequences are also relatively comparable, suggesting that duration rather than elevation changes affects neuromuscular function and running patterns. However, 'pure' uphill or downhill running has several fatigue-related intrinsic features compared with the level running. Downhill running induces severe lower limb tissue damage, indirectly evidenced by massive increases in plasma creatine kinase/myoglobin concentration or inflammatory markers. In addition, low-frequency fatigue (i.e., excitation-contraction coupling failure) is systematically observed after downhill running, although it has also been found in high-intensity uphill running for different reasons. Indeed, low-frequency fatigue in downhill running is attributed to mechanical stress at the interface sarcoplasmic reticulum/T-tubule, while the inorganic phosphate accumulation probably plays a central role in intense uphill running. Other fatigue-related specificities of graded running such as strategies to minimize the deleterious effects of downhill running on muscle function, the difference of energy cost versus heat storage or muscle activity changes in downhill, level, and uphill running are also discussed.

  4. Dr. Sheehan on Running.

    ERIC Educational Resources Information Center

    Sheehan, George A.

    This book is both a personal and technical account of the experience of running by a heart specialist who began a running program at the age of 45. In its seventeen chapters, there is information presented on the spiritual, psychological, and physiological results of running; treatment of athletic injuries resulting from running; effects of diet…

  5. Dr. Sheehan on Running.

    ERIC Educational Resources Information Center

    Sheehan, George A.

    This book is both a personal and technical account of the experience of running by a heart specialist who began a running program at the age of 45. In its seventeen chapters, there is information presented on the spiritual, psychological, and physiological results of running; treatment of athletic injuries resulting from running; effects of diet…

  6. Nonperturbative imaging of nucleoid morphology in live bacterial cells during an antimicrobial peptide attack.

    PubMed

    Bakshi, Somenath; Choi, Heejun; Rangarajan, Nambirajan; Barns, Kenneth J; Bratton, Benjamin P; Weisshaar, James C

    2014-08-01

    Studies of time-dependent drug and environmental effects on single, live bacterial cells would benefit significantly from a permeable, nonperturbative, long-lived fluorescent stain specific to the nucleoids (chromosomal DNA). The ideal stain would not affect cell growth rate or nucleoid morphology and dynamics, even during laser illumination for hundreds of camera frames. In this study, time-dependent, single-cell fluorescence imaging with laser excitation and a sensitive electron-multiplying charge-coupled-device (EMCCD) camera critically tested the utility of "dead-cell stains" (SYTOX orange and SYTOX green) and "live-cell stains" (DRAQ5 and SYTO 61) and also 4',6-diamidino-2-phenylindole (DAPI). Surprisingly, the dead-cell stains were nearly ideal for imaging live Escherichia coli, while the live-cell stains and DAPI caused nucleoid expansion and, in some cases, cell permeabilization and the halting of growth. SYTOX orange performed well for both the Gram-negative E. coli and the Gram-positive Bacillus subtilis. In an initial application, we used two-color fluorescence imaging to show that the antimicrobial peptide cecropin A destroyed nucleoid-ribosome segregation over 20 min after permeabilization of the E. coli cytoplasmic membrane, reminiscent of the long-term effects of the drug rifampin. In contrast, the human cathelicidin LL-37, while similar to cecropin A in structure, length, charge, and the ability to permeabilize bacterial membranes, had no observable effect on nucleoid-ribosome segregation. Possible underlying causes are suggested. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  7. Running and Breathing in Mammals

    NASA Astrophysics Data System (ADS)

    Bramble, Dennis M.; Carrier, David R.

    1983-01-01

    Mechanical constraints appear to require that locomotion and breathing be synchronized in running mammals. Phase locking of limb and respiratory frequency has now been recorded during treadmill running in jackrabbits and during locomotion on solid ground in dogs, horses, and humans. Quadrupedal species normally synchronize the locomotor and respiratory cycles at a constant ratio of 1:1 (strides per breath) in both the trot and gallop. Human runners differ from quadrupeds in that while running they employ several phase-locked patterns (4:1, 3:1, 2:1, 1:1, 5:2, and 3:2), although a 2:1 coupling ratio appears to be favored. Even though the evolution of bipedal gait has reduced the mechanical constraints on respiration in man, thereby permitting greater flexibility in breathing pattern, it has seemingly not eliminated the need for the synchronization of respiration and body motion during sustained running. Flying birds have independently achieved phase-locked locomotor and respiratory cycles. This hints that strict locomotor-respiratory coupling may be a vital factor in the sustained aerobic exercise of endothermic vertebrates, especially those in which the stresses of locomotion tend to deform the thoracic complex.

  8. Nonperturbative gluon and ghost propagators for d=3 Yang-Mills theory

    SciTech Connect

    Aguilar, A. C.; Binosi, D.; Papavassiliou, J.

    2010-06-15

    We study a manifestly gauge-invariant set of Schwinger-Dyson equations to determine the nonperturbative dynamics of the gluon and ghost propagators in d=3 Yang-Mills theory. The use of the well-known Schwinger mechanism, in the Landau gauge leads to the dynamical generation of a mass for the gauge boson (gluon in d=3), which, in turn, gives rise to an infrared finite gluon propagator and ghost dressing function. The propagators obtained from the numerical solution of these nonperturbative equations are in very good agreement with the results of SU(2) lattice simulations.

  9. Nonperturbative improvement of stout-smeared three-flavor clover fermions

    SciTech Connect

    Cundy, N.; Goeckeler, M.; Kaltenbrunner, T.; Schaefer, A.; Horsley, R.; Kennedy, A. D.; Zanotti, J. M.; Nakamura, Y.; Perlt, H.; Schiller, A.; Pleiter, D.; Rakow, P. E. L.; Schierholz, G.; Stueben, H.

    2009-05-01

    We discuss a three-flavor lattice QCD action with clover improvement in which the fermion matrix has single level stout smearing for the hopping terms together with unsmeared links for the clover term. With the (tree-level) Symanzik improved gluon action this constitutes the stout link nonperturbative clover or SLiNC action. To cancel O(a) terms the clover term coefficient has to be tuned. We present here results of a nonperturbative determination of this coefficient using the Schroedinger functional and as a by-product a determination of the critical hopping parameter. Comparisons of the results are made with lowest order perturbation theory.

  10. On Running and Psychotherapy.

    ERIC Educational Resources Information Center

    Dukes, Denzel; And Others

    1980-01-01

    Frederic Leer's article "Running as an Adjunct to Psychotherapy" (January 1980 issue of this journal) is criticized by three authors. They focus on the psychological and social effects of running and its usefulness as a treatment for depressed adults. (LAB)

  11. Biomechanics of Distance Running.

    ERIC Educational Resources Information Center

    Cavanagh, Peter R., Ed.

    Contributions from researchers in the field of running mechanics are included in the 13 chapters of this book. The following topics are covered: (1) "The Mechanics of Distance Running: A Historical Perspective" (Peter Cavanagh); (2) "Stride Length in Distance Running: Velocity, Body Dimensions, and Added Mass Effects" (Peter Cavanagh, Rodger…

  12. Biomechanics of Distance Running.

    ERIC Educational Resources Information Center

    Cavanagh, Peter R., Ed.

    Contributions from researchers in the field of running mechanics are included in the 13 chapters of this book. The following topics are covered: (1) "The Mechanics of Distance Running: A Historical Perspective" (Peter Cavanagh); (2) "Stride Length in Distance Running: Velocity, Body Dimensions, and Added Mass Effects" (Peter Cavanagh, Rodger…

  13. PREFACE: Loops 11: Non-Perturbative / Background Independent Quantum Gravity

    NASA Astrophysics Data System (ADS)

    Mena Marugán, Guillermo A.; Barbero G, J. Fernando; Garay, Luis J.; Villaseñor, Eduardo J. S.; Olmedo, Javier

    2012-05-01

    Loops 11 The international conference LOOPS'11 took place in Madrid from the 23-28 May 2011. It was hosted by the Instituto de Estructura de la Materia (IEM), which belongs to the Consejo Superior de Investigaciones Cientĺficas (CSIC). Like previous editions of the LOOPS meetings, it dealt with a wealth of state-of-the-art topics on Quantum Gravity, with special emphasis on non-perturbative background-independent approaches to spacetime quantization. The main topics addressed at the conference ranged from the foundations of Quantum Gravity to its phenomenological aspects. They encompassed different approaches to Loop Quantum Gravity and Cosmology, Polymer Quantization, Quantum Field Theory, Black Holes, and discrete approaches such as Dynamical Triangulations, amongst others. In addition, this edition celebrated the 25th anniversary of the introduction of the now well-known Ashtekar variables and the Wednesday morning session was devoted to this silver jubilee. The structure of the conference was designed to reflect the current state and future prospects of research on the different topics mentioned above. Plenary lectures that provided general background and the 'big picture' took place during the mornings, and the more specialised talks were distributed in parallel sessions during the evenings. To be more specific, Monday evening was devoted to Shape Dynamics and Phenomenology Derived from Quantum Gravity in Parallel Session A, and to Covariant Loop Quantum Gravity and Spin foams in Parallel Session B. Tuesday's three Parallel Sessions dealt with Black Hole Physics and Dynamical Triangulations (Session A), the continuation of Monday's session on Covariant Loop Quantum Gravity and Spin foams (Session B) and Foundations of Quantum Gravity (Session C). Finally, Thursday and Friday evenings were devoted to Loop Quantum Cosmology (Session A) and to Hamiltonian Loop Quantum Gravity (Session B). The result of the conference was very satisfactory and enlightening. Not

  14. Non-perturbative effects in quantum field theory: QCD, supersymmetric QCD and axions

    NASA Astrophysics Data System (ADS)

    Wu, Weitao

    In the study of non-perturbative effects in four dimenstional non-Abelian gauge theories, instantons have played an important conceptual role. However, their role in the quantitative understanding these theories has remained obscure. In the first part of this thesis, we revisit the question of whether or not one can perform reliable semiclassical QCD computation at zero temperature. We study correlation functions with no perturbative contributions, and organize the problem by means of the operator product expansion, establishing a precise criterion for the validity of semiclassical calculation. For N f > Nc, a systematic computation is possible; for Nf < Nc, it is not. Nf = Nc is a borderline case. As an application, we describe a test of QCD lattice gauge theory computations in the chiral limit. Supersymmetry has provided a tool with which to obtain a range of exact results in field theory and string theory. Arguably the first inkling that one could obtain such results was the work of Novikov, Shifman, Vainshtein, and Zakharov (NSVZ). They argued for two exact results in gauge theories using instanton computation. First, that one could compute certain correlation functions exactly at weak coupling, and extend the results to strong coupling; second, that one could obtain exact expressions for beta-functions. However, each of these results raised questions. As methods exploiting systematic weak coupling expansions and holomorphy were developed, it became clear that the strong coupling instanton computation was incorrect. This in turn called the exact beta-function into question. In the second part of this thesis, we will provide resolutions to both of these questions. First, we explain why the instanton computation in the pure supersymmetric gauge theory is not reliable, even at short distances. The semiclassical expansion about the instanton is purely formal; if infrared divergences appear, they spoil arguments based on holomorphy. For the question of the NSVZbeta

  15. Holomorphy, triality, and nonperturbative beta function in 2D supersymmetric QCD

    NASA Astrophysics Data System (ADS)

    Gadde, Abhijit

    2016-07-01

    In this paper, we study the RG flow in the nonlinear sigma models obtained from a 2D N =(0 ,2 ) supersymmetric QCD. The sigma model is parametrized by a single Kahler modulus. We determine its exact nonperturbative beta function using holomorphy, triality and the knowledge of the infrared fixed point.

  16. Nonperturbative Calculation of Born-Infeld Effects on the Schroedinger Spectrum of the Hydrogen Atom

    SciTech Connect

    Carley, Holly; Kiessling, Michael K.-H.

    2006-01-27

    We present the first nonperturbative calculations of the nonrelativistic hydrogen spectrum as predicted by first-quantized nonlinear Maxwell-Born-Infeld electrodynamics with point charges. Judged against empirical data our results significantly restrict the range of viable values of the new electromagnetic constant {beta} introduced by Born. We assess Born's own proposal for the value of {beta}.

  17. Nonperturbative renormalization of meson decay constants in quenched QCD for a renormalization group improved gauge action

    SciTech Connect

    Ide, K.; Aoki, S.; Kanaya, K.; Taniguchi, Y.; Burkhalter, R.; Ishikawa, K.-I.; Ishizuka, N.; Iwasaki, Y.; Ukawa, A.; Yoshie, T.; Fukugita, M.; Hashimoto, S.; Kaneko, T.; Kuramashi, Y.; Ishikawa, T.; Lesk, V.; Umeda, T.; Okawa, M.

    2004-10-01

    Renormalization constants (Z-factors ) of vector and axial-vector currents are determined nonperturbatively in quenched QCD for a renormalization group improved gauge action and a tadpole-improved clover quark action using the Schroedinger functional method. Nonperturbative values of Z-factors turn out to be smaller than 1-loop perturbative values by O(15%) at a lattice spacing of a{sup -1}{approx_equal} 1 GeV. The pseudoscalar and vector meson decay constants calculated with the nonperturbative Z-factors show a much better scaling behavior compared to previous results obtained with tadpole-improved one-loop Z-factors. In particular, the nonperturbative Z-factors normalized at infinite physical volume show that the scaling violations of the decay constants are within about 10% up to the lattice spacing a{sup -1}{approx}1 GeV. The continuum estimates obtained from data in the range a{sup -1}{approx} 1-2 GeV agree with those determined from finer lattices (a{sup -1}{approx}2-4 GeV) with the standard action.

  18. Nonperturbative spectral-density function for the Anderson model at arbitrary temperatures

    NASA Technical Reports Server (NTRS)

    Neal, Henry L.

    1991-01-01

    Using a nonperturbative self-energy solution for the nondegenerate Anderson model, the temperature-dependent spectral-density function is calculated in the symmetric limit. The function is found to give reliable results for all values of the parameter u and inverse temperature beta.

  19. Non-perturbative structure in heterotic strings from dual F-theory models

    NASA Astrophysics Data System (ADS)

    O'Driscoll, Dónal

    1999-05-01

    We examine how to construct explicit heterotic string models dual to F-theory in eight dimensions. In doing so we learn about where the moduli spaces of the two theories overlap, and how non-perturbative features leave their trace on a purely perturbative level. We also briefly look at the relationship with NS9-branes

  20. Spectral zeta function and non-perturbative effects in ABJM Fermi-gas

    NASA Astrophysics Data System (ADS)

    Hatsuda, Yasuyuki

    2015-11-01

    The exact partition function in ABJM theory on three-sphere can be regarded as a canonical partition function of a non-interacting Fermi-gas with an unconventional Hamiltonian. All the information on the partition function is encoded in the discrete spectrum of this Hamiltonian. We explain how (quantum mechanical) non-perturbative corrections in the Fermi-gas system appear from a spectral consideration. Basic tools in our analysis are a Mellin-Barnes type integral representation and a spectral zeta function. From a consistency with known results, we conjecture that the spectral zeta function in the ABJM Fermi-gas has an infinite number of "non-perturbative" poles, which are invisible in the semi-classical expansion of the Planck constant. We observe that these poles indeed appear after summing up perturbative corrections. As a consequence, the perturbative resummation of the spectral zeta function causes non-perturbative corrections to the grand canonical partition function. We also present another example associated with a spectral problem in topological string theory. A conjectured non-perturbative free energy on the resolved conifold is successfully reproduced in this framework.

  1. Perturbative and nonperturbative contributions to the strange quark asymmetry in the nucleon

    NASA Astrophysics Data System (ADS)

    Feng, Guan-Qiu; Cao, Fu-Guang; Guo, Xin-Heng; Signal, A. I.

    2012-12-01

    There are two mechanisms for the generation of an asymmetry between the strange and anti-strange quark distributions in the nucleon: nonperturbative contributions originating from nucleons fluctuating into virtual baryon-meson pairs such as ΛK and ΣK, and perturbative contributions arising from gluons splitting into strange and anti-strange quark pairs. While the nonperturbative contributions are dominant in the large- x region, the perturbative contributions are more significant in the small- x region. We calculate this asymmetry taking into account both nonperturbative and perturbative contributions, thus giving a more accurate evaluation of this asymmetry over the whole domain of x. We find that the perturbative contributions are generally a few times larger in magnitude than the nonperturbative contributions, which suggests that the best region to detect this asymmetry experimentally is in the region 0.02< x<0.03. We find that the asymmetry may have more than one node, which is an effect that should be taken into account, e.g. for parameterizations of the strange and anti-strange quark distributions used in global analysis of parton distributions.

  2. Reheating dynamics affects non-perturbative decay of spectator fields

    SciTech Connect

    Enqvist, Kari; Lerner, Rose N.; Rusak, Stanislav E-mail: rose.lerner@helsinki.fi

    2013-11-01

    The behaviour of oscillating scalar spectator fields after inflation depends on the thermal background produced by inflaton decay. Resonant decay of the spectator is often blocked by large induced thermal masses. We account for the finite decay width of the inflaton and the protracted build-up of the thermal bath to determine the early evolution of a homogeneous spectator field σ coupled to the Higgs Boson Φ through the term g{sup 2}σ{sup 2}Φ{sup 2}, the only renormalisable coupling of a new scalar to the Standard Model. We find that for very large higgs-spectator coupling g∼>10{sup −3}, the resonance is not always blocked as was previously suggested. As a consequence, the oscillating spectator can decay quickly. For other parameter values, we find that although qualitative features of the thermal blocking still hold, the dynamics are altered compared to the instant decay case. These findings are important for curvaton models, where the oscillating field must be relatively long lived in order to produce the curvature perturbation. They are also relevant for other spectator fields, which must decay sufficiently early to avoid spoiling the predictions of baryogenesis and nucleosynthesis.

  3. Dressed skeleton expansion and the coupling scale ambiguity problem

    SciTech Connect

    Lu, Hung Jung

    1992-09-01

    Perturbative expansions in quantum field theories are usually expressed in powers of a coupling constant. In principle, the infinite sum of the expansion series is independent of the renormalization scale of the coupling constant. In practice, there is a remnant dependence of the truncated series on the renormalization scale. This scale ambiguity can severely restrict the predictive power of theoretical calculations. The dressed skeleton expansion is developed as a calculational method which avoids the coupling scale ambiguity problem. In this method, physical quantities are expressed as functional expansions in terms of a coupling vertex function. The arguments of the vertex function are given by the physical momenta of each process. These physical momenta effectively replace the unspecified renormalization scale and eliminate the ambiguity problem. This method is applied to various field theoretical models and its main features and limitations are explored. For quantum chromodynamics, an expression for the running coupling constant of the three-gluon vertex is obtained. The effective coupling scale of this vertex is shown to be essentially given by {mu}{sup 2} {approximately} Q{sub min}{sup 2}Q{sub med}{sup 2}/Q{sub max}{sup 2} where Q{sub min}{sup 2}Q{sub med}{sup 2}/Q{sub max}{sup 2} are respectively the smallest, the next-to-smallest and the largest scale among the three gluon virtualities. This functional form suggests that the three-gluon vertex becomes non-perturbative at asymmetric momentum configurations. Implications for four-jet physics is discussed.

  4. Nonperturbative solution of the Ising model on a random surface

    SciTech Connect

    Gross, D.J.; Migdal, A.A. )

    1990-02-12

    The two-matrix-model representation of the Ising model on a random surface is solved exactly to all orders in the genus expansion. The partition function obeys a fourth-order nonlinear differential equation as a function of the string coupling constant. This equation differs from that derived for the {ital k}=3 multicritical one-matrix model, thus disproving that this model describes the Ising model. A similar equation is derived for the Yang-Lee edge singularity on a random surface, and is shown to agree with the {ital k}=3 multicritical one-matrix model.

  5. Triathlon: running injuries.

    PubMed

    Spiker, Andrea M; Dixit, Sameer; Cosgarea, Andrew J

    2012-12-01

    The running portion of the triathlon represents the final leg of the competition and, by some reports, the most important part in determining a triathlete's overall success. Although most triathletes spend most of their training time on cycling, running injuries are the most common injuries encountered. Common causes of running injuries include overuse, lack of rest, and activities that aggravate biomechanical predisposers of specific injuries. We discuss the running-associated injuries in the hip, knee, lower leg, ankle, and foot of the triathlete, and the causes, presentation, evaluation, and treatment of each.

  6. Overcoming the "Run" Response

    ERIC Educational Resources Information Center

    Swanson, Patricia E.

    2013-01-01

    Recent research suggests that it is not simply experiencing anxiety that affects mathematics performance but also how one responds to and regulates that anxiety (Lyons and Beilock 2011). Most people have faced mathematics problems that have triggered their "run response." The issue is not whether one wants to run, but rather…

  7. A new approach to analytic, non-perturbative and gauge-invariant QCD

    SciTech Connect

    Fried, H.M.; Grandou, T.; Sheu, Y.-M.

    2012-11-15

    Following a previous calculation of quark scattering in eikonal approximation, this paper presents a new, analytic and rigorous approach to the calculation of QCD phenomena. In this formulation a basic distinction between the conventional 'idealistic' description of QCD and a more 'realistic' description is brought into focus by a non-perturbative, gauge-invariant evaluation of the Schwinger solution for the QCD generating functional in terms of the exact Fradkin representations of Green's functional G{sub c}(x,y|A) and the vacuum functional L[A]. Because quarks exist asymptotically only in bound states, their transverse coordinates can never be measured with arbitrary precision; the non-perturbative neglect of this statement leads to obstructions that are easily corrected by invoking in the basic Lagrangian a probability amplitude which describes such transverse imprecision. The second result of this non-perturbative analysis is the appearance of a new and simplifying output called 'Effective Locality', in which the interactions between quarks by the exchange of a 'gluon bundle'-which 'bundle' contains an infinite number of gluons, including cubic and quartic gluon interactions-display an exact locality property that reduces the several functional integrals of the formulation down to a set of ordinary integrals. It should be emphasized that 'non-perturbative' here refers to the effective summation of all gluons between a pair of quark lines-which may be the same quark line, as in a self-energy graph-but does not (yet) include a summation over all closed-quark loops which are tied by gluon-bundle exchange to the rest of the 'Bundle Diagram'. As an example of the power of these methods we offer as a first analytic calculation the quark-antiquark binding potential of a pion, and the corresponding three-quark binding potential of a nucleon, obtained in a simple way from relevant eikonal scattering approximations. A second calculation, analytic, non-perturbative and

  8. Nonperturbative O(a) improvement of Wilson quark action in three-flavor QCD with plaquette gauge action

    SciTech Connect

    Yamada, N.; Hashimoto, S.; Kaneko, T.; Tsutsui, N.; Aoki, S.; Taniguchi, Y.; Fukugita, M.; Ishikawa, K-I.; Okawa, M.; Ishizuka, N.; Iwasaki, Y.; Kanaya, K.; Kuramashi, Y.; Ukawa, A.; Yoshie, T.

    2005-03-01

    We perform a nonperturbative determination of the O(a)-improvement coefficient c{sub SW} for the Wilson quark action in three-flavor QCD with the plaquette gauge action. Numerical simulations are carried out in a range of {beta}=12.0-5.2 on a single lattice size of 8{sup 3}x16 employing the Schroedinger functional setup of lattice QCD. As our main result, we obtain an interpolation formula for c{sub SW} and the critical hopping parameter K{sub c} as a function of the bare coupling. This enables us to remove the O(a) scaling violation from physical observables in future numerical simulation in the wide range of {beta}. Our analysis with a perturbatively modified improvement condition for c{sub SW} suggests that finite volume effects in c{sub SW} are not large on the 8{sup 3}x16 lattice. We investigate N{sub f} dependence of c{sub SW} by additional simulations for N{sub f}=4, 2, and 0 at {beta}=9.6. As a preparatory step for this study, we also determine c{sub SW} in two-flavor QCD at {beta}=5.2. At this {beta}, several groups have carried out large-scale calculations of the hadron spectrum, while no systematic determination of c{sub SW} has been performed.

  9. ER = EPR and non-perturbative action integrals for quantum gravity

    NASA Astrophysics Data System (ADS)

    Alsaleh, Salwa; Alasfar, Lina

    In this paper, we construct and calculate non-perturbative path integrals in a multiply-connected spacetime. This is done by summing over homotopy classes of paths. The topology of the spacetime is defined by Einstein-Rosen bridges (ERB) forming from the entanglement of quantum foam described by virtual black holes. As these “bubbles” are entangled, they are connected by Planckian ERBs because of the ER = EPR conjecture. Hence, the spacetime will possess a large first Betti number B1. For any compact 2-surface in the spacetime, the topology (in particular the homotopy) of that surface is non-trivial due to the large number of Planckian ERBs that define homotopy through this surface. The quantization of spacetime with this topology — along with the proper choice of the 2-surfaces — is conjectured to allow non-perturbative path integrals of quantum gravity theory over the spacetime manifold.

  10. Final state interactions and the transverse structure of the pion using non-perturbative eikonal methods

    SciTech Connect

    Gamberg, Leonard; Schlegel, Marc

    2010-01-18

    In the factorized picture of semi-inclusive hadronic processes the naive time reversal-odd parton distributions exist by virtue of the gauge link which renders it color gauge invariant. The link characterizes the dynamical effect of initial/final-state interactions of the active parton due soft gluon exchanges with the target remnant. Though these interactions are non-perturbative, studies of final-state interaction have been approximated by perturbative one-gluon approximation in Abelian models. We include higher-order contributions by applying non-perturbative eikonal methods incorporating color degrees of freedom in a calculation of the Boer-Mulders function of the pion. Lastly, using this framework we explore under what conditions the Boer Mulders function can be described in terms of factorization of final state interactions and a spatial distribution in impact parameter space.

  11. Final state interactions and the transverse structure of the pion using non-perturbative eikonal methods

    DOE PAGES

    Gamberg, Leonard; Schlegel, Marc

    2010-01-18

    In the factorized picture of semi-inclusive hadronic processes the naive time reversal-odd parton distributions exist by virtue of the gauge link which renders it color gauge invariant. The link characterizes the dynamical effect of initial/final-state interactions of the active parton due soft gluon exchanges with the target remnant. Though these interactions are non-perturbative, studies of final-state interaction have been approximated by perturbative one-gluon approximation in Abelian models. We include higher-order contributions by applying non-perturbative eikonal methods incorporating color degrees of freedom in a calculation of the Boer-Mulders function of the pion. Lastly, using this framework we explore under what conditionsmore » the Boer Mulders function can be described in terms of factorization of final state interactions and a spatial distribution in impact parameter space.« less

  12. Non-perturbative BRST quantization of Euclidean Yang-Mills theories in Curci-Ferrari gauges

    NASA Astrophysics Data System (ADS)

    Pereira, A. D.; Sobreiro, R. F.; Sorella, S. P.

    2016-10-01

    In this paper we address the issue of the non-perturbative quantization of Euclidean Yang-Mills theories in the Curci-Ferrari gauge. In particular, we construct a refined Gribov-Zwanziger action for this gauge, which takes into account the presence of gauge copies as well as the dynamical formation of dimension-two condensates. This action enjoys a non-perturbative BRST symmetry recently proposed in Capri et al. (Phys. Rev. D 92(4), 045039. doi: 10.1103/PhysRevD.92.045039 arXiv:1506.06995 [hep-th], 2015). Finally, we pay attention to the gluon propagator in different space-time dimensions.

  13. Non-perturbative twist of attosecond extreme-ultraviolet vortex beams

    NASA Astrophysics Data System (ADS)

    Hernández García, Carlos; Rego, Laura; San Román, Julio; Picón, Antonio; Plaja, Luis

    2017-02-01

    Extreme-ultraviolet (EUV) attosecond vortices carrying orbital angular momentum (OAM) are produced through high-order harmonic generation (HHG) from the nonlinear conversion of infrared twisted beams. While previous works demonstrated a linear scaling law of the vortex OAM content with the harmonic order, an unexpectedly rich scenario for the OAM buildup appears when HHG is driven by a vortex combination. The non-perturbative nature of HHG increases the OAM content of the attosecond vortices when the driving field presents an azimuthally varying intensity profile. We theoretically explore the underlying mechanisms for this diversity and disentangle the perturbative and non-perturbative nature in the generation of EUV attosecond twisted through numerical simulations.

  14. Nonperturbative Twist in the Generation of Extreme-Ultraviolet Vortex Beams.

    PubMed

    Rego, Laura; Román, Julio San; Picón, Antonio; Plaja, Luis; Hernández-García, Carlos

    2016-10-14

    High-order harmonic generation (HHG) has been recently proven to produce extreme-ultraviolet (XUV) vortices from the nonlinear conversion of infrared twisted beams. Previous works have demonstrated a linear scaling law of the vortex charge with the harmonic order. We demonstrate that this simple law hides an unexpectedly rich scenario for the buildup of orbital angular momentum (OAM) due to the nonperturbative behavior of HHG. The complexity of these twisted XUV beams appears only when HHG is driven by nonpure vortex modes, where the XUV OAM content is dramatically increased. We explore the underlying mechanisms for this diversity and derive a general conservation rule for the nonperturbative OAM buildup. The simple scaling found in previous works corresponds to the collapse of this scenario for the particular case of pure (single-mode) OAM driving fields.

  15. An exact, finite, gauge-invariant, non-perturbative approach to QCD renormalization

    SciTech Connect

    Fried, H.M.; Tsang, P.H.; Gabellini, Y.; Grandou, T.; Sheu, Y.-M.

    2015-08-15

    A particular choice of renormalization, within the simplifications provided by the non-perturbative property of Effective Locality, leads to a completely finite, non-perturbative approach to renormalized QCD, in which all correlation functions can, in principle, be defined and calculated. In this Model of renormalization, only the Bundle chain-Graphs of the cluster expansion are non-zero. All Bundle graphs connecting to closed quark loops of whatever complexity, and attached to a single quark line, provided no ‘self-energy’ to that quark line, and hence no effective renormalization. However, the exchange of momentum between one quark line and another, involves only the cluster-expansion’s chain graphs, and yields a set of contributions which can be summed and provide a finite color-charge renormalization that can be incorporated into all other QCD processes. An application to High Energy elastic pp scattering is now underway.

  16. Double nonperturbative gluon exchange: An update on the soft-Pomeron contribution to p p scattering

    NASA Astrophysics Data System (ADS)

    Canfora, F. E.; Dudal, D.; Justo, I. F.; Pais, P.; Salgado-Rebolledo, P.; Rosa, L.; Vercauteren, D.

    2017-08-01

    We employ a set of recent, theoretically motivated fits to nonperturbative unquenched gluon propagators to check on how far double gluon exchange can be used to describe the soft sector of p p scattering data (total and differential cross section). In particular, we use the refined Gribov-Zwanziger gluon propagator (as arising from dealing with the Gribov gauge fixing ambiguity) and the massive Cornwall-type gluon propagator (as motivated from Dyson-Schwinger equations) in conjunction with a perturbative quark-gluon vertex, next to a model based on the nonperturbative quark-gluon Maris-Tandy vertex, popular from Bethe-Salpeter descriptions of hadronic bound states. We compare the cross sections arising from these models with older ISR and more recent TOTEM and ATLAS data. The lower the value of total energy √{s }, the better the results appear to be.

  17. Nonperturbative ab initio calculations in strong magnetic fields using London orbitals

    NASA Astrophysics Data System (ADS)

    Tellgren, Erik I.; Soncini, Alessandro; Helgaker, Trygve

    2008-10-01

    A self-consistent field (SCF) London-orbital computational scheme to perform gauge-origin independent nonperturbative calculations for molecules in strong magnetic fields is presented. The crucial difference in the proposed approach with respect to common-origin finite-field SCF implementations consists in the evaluation of molecular integrals over the field-dependent molecular basis functions, which is tantamount to computing molecular integrals in a hybrid Gaussian and plane-wave basis set. The implementation of a McMurchie-Davidson scheme for the calculation of the molecular integrals over London orbitals is discussed, and preliminary applications of the newly developed code to the calculation of fourth-rank hypermagnetizabilities for a set of small molecules, benzene, and cyclobutadiene are presented. The nonperturbative approach is particularly useful for studying the highly nonlinear response of paramagnetic closed-shell systems such as boron monohydride, or the π-electron response of cyclobutadiene.

  18. Nonperturbative Twist in the Generation of Extreme-Ultraviolet Vortex Beams

    NASA Astrophysics Data System (ADS)

    Rego, Laura; Román, Julio San; Picón, Antonio; Plaja, Luis; Hernández-García, Carlos

    2016-10-01

    High-order harmonic generation (HHG) has been recently proven to produce extreme-ultraviolet (XUV) vortices from the nonlinear conversion of infrared twisted beams. Previous works have demonstrated a linear scaling law of the vortex charge with the harmonic order. We demonstrate that this simple law hides an unexpectedly rich scenario for the buildup of orbital angular momentum (OAM) due to the nonperturbative behavior of HHG. The complexity of these twisted XUV beams appears only when HHG is driven by nonpure vortex modes, where the XUV OAM content is dramatically increased. We explore the underlying mechanisms for this diversity and derive a general conservation rule for the nonperturbative OAM buildup. The simple scaling found in previous works corresponds to the collapse of this scenario for the particular case of pure (single-mode) OAM driving fields.

  19. Run Anyone?... Everyone!

    PubMed Central

    McInnis, W. P.

    1974-01-01

    Fitness and health have become bywords in the past decade, signifying increased emphasis on these factors as necessary for good psychological and physical health. Reasons are given why we should run and how to do it. There is a discussion of the technique of running, and equipment. Brief mention is made of complications. An attempt is made to interest the individual in the benefits of running as a sport as well as the best method for the average person to achieve fitness and health. PMID:20469054

  20. Non-perturbative effect and PAMELA limit on electro-weak dark matter

    NASA Astrophysics Data System (ADS)

    Chun, Eung Jin; Park, Jong-Chul; Scopel, Stefano

    2012-12-01

    We discuss the non-perturbative effects on the annihilation cross section of an Electro-Weak Dark Matter (EWDM) particle belonging to an electroweak multiplet when the splittings between the masses of the DM component and the other charged or neutral component(s) of the multiplet are treated as free parameters. Our analysis shows that EWDM exhibits not only the usual Sommerfeld enhancement with resonance peaks but also dips where the cross section is suppressed. Moreover, we have shown that the non-perturbative effects become important even when the EWDM mass is below the TeV scale, provided that some of the mass splittings are reduced to the order of a few MeV. This extends the possibility of observing sizeable non-perturbative effects in the dark matter annihilation to values of the dark matter mass significantly smaller than previously considered, since only electroweak-induced mass splittings larger than 100 MeV have been discussed in the literature so far. We have then used the available experimental data on the cosmic antiproton flux to constrain the EWDM parameter space. In our calculation of the expected signal we have included the effect of the convolution of the cross section with the velocity distribution of the dark matter particles in the Galaxy, showing that it can alter the non-perturbative effects significantly. In the case of EWDM with non-zero hypercharge, we have shown that the mass splitting in the Dirac dark matter fermion can be chosen so that the inelastic cross section of the EWDM off nuclei is allowed by present direct detection constraints and at the same time is within the reach of future experiments.

  1. Non-perturbative effects for the Quark-Gluon Plasma equation of state

    NASA Astrophysics Data System (ADS)

    Begun, V. V.; Gorenstein, M. I.; Mogilevsky, O. A.

    2012-07-01

    The non-perturbative effects for the Quark-Gluon Plasma (QGP) equation of state (EoS) are considered. The modifications of the bag model EoS are constructed to satisfy the main qualitative features observed for the QGP EoS in the lattice QCD calculations. A quantitative comparison with the lattice results is done for the SU(3) gluon plasma and for the QGP with dynamical quarks. Our analysis advocates a negative value of the bag constant B.

  2. Nonperturbative Strange Sea in Proton Using Wave Functions Inspired by Light Front Holography

    NASA Astrophysics Data System (ADS)

    Vega, Alfredo; Schmidt, Ivan; Gutsche, Thomas; Lyubovitskij, Valery E.

    2017-03-01

    We use different light-front wave functions (two inspired by the AdS/QCD formalism), together with a model of the nucleon in terms of meson-baryon fluctuations to calculate the nonperturbative (intrinsic) contribution to the s(x) - bar{s}(x) asymmetry of the proton sea. The holographic wave functions for an arbitrary number of constituents, recently derived by us, give results quite close to known parametrizations that appear in the literature.

  3. A nonperturbative definition of N = 4 Super Yang-Mills by the plane wave matrix model

    SciTech Connect

    Shimasaki, Shinji

    2008-11-23

    We propose a nonperturbative definition of N = 4 Super Yang-Mills(SYM). We realize N = 4 SYM on RxS{sup 3} as the theory around a vacuum of the plane wave matrix model. Our regularization preserves 16 supersymmetries and the gauge symmetry. We perform the one-loop calculation to give evidence that in the continuum limit the superconformal symmetry is restored.

  4. Pauli-Villars regularization in nonperturbative Hamiltonian approach on the light front

    SciTech Connect

    Malyshev, M. Yu. Paston, S. A.; Prokhvatilov, E. V.; Zubov, R. A.; Franke, V. A.

    2016-01-22

    The advantage of Pauli-Villars regularization in quantum field theory quantized on the light front is explained. Simple examples of scalar λφ{sup 4} field theory and Yukawa-type model are used. We give also an example of nonperturbative calculation in the theory with Pauli-Villars fields, using for that a model of anharmonic oscillator modified by inclusion of ghost variables playing the role similar to Pauli-Villars fields.

  5. High-order harmonic generation from gapped graphene: Perturbative response and transition to nonperturbative regime

    NASA Astrophysics Data System (ADS)

    Dimitrovski, Darko; Madsen, Lars Bojer; Pedersen, Thomas Garm

    2017-01-01

    We consider the interaction of gapped graphene in the two-band approximation using an explicit time-dependent approach. In addition to the full high-order harmonic generation (HHG) spectrum, we also obtain the perturbative harmonic response using the time-dependent method at photon energies covering all the significant features in the responses. The transition from the perturbative to the fully nonperturbative regime of HHG at these photon energies is studied in detail.

  6. Non-perturbative renormalisation of left left four-fermion operators with Neuberger fermions

    NASA Astrophysics Data System (ADS)

    Dimopoulos, P.; Giusti, L.; Hernández, P.; Palombi, F.; Pena, C.; Vladikas, A.; Wennekers, J.; Wittig, H.

    2006-09-01

    We outline a general strategy for the non-perturbative renormalisation of composite operators in discretisations based on Neuberger fermions, via a matching to results obtained with Wilson-type fermions. As an application, we consider the renormalisation of the four-quark operators entering the ΔS = 1 and ΔS = 2 effective Hamiltonians. Our results are an essential ingredient for the determination of the low-energy constants governing non-leptonic kaon decays.

  7. NON-PERTURBATIVE GLUODYNAMICS OF HIGH ENERGY HEAVY-ION COLLISIONS

    SciTech Connect

    KRASNITZ,A.; VENUGOPALAN,R.

    2000-01-03

    The dynamics of low-x partons in the transverse plane of a high-energy nuclear collision is classical, and therefore admits a fully non-perturbative numerical treatment. The authors report results of a recent study estimating the initial energy density in the central region of a collision. Preliminary estimates of the number of gluons per unit rapidity, and the initial transverse momentum distribution of gluons, are also provided.

  8. Non-perturbative effects for the Quark-Gluon Plasma equation of state

    SciTech Connect

    Begun, V. V. Gorenstein, M. I. Mogilevsky, O. A.

    2012-07-15

    The non-perturbative effects for the Quark-Gluon Plasma (QGP) equation of state (EoS) are considered. The modifications of the bag model EoS are constructed to satisfy the main qualitative features observed for the QGP EoS in the lattice QCD calculations. A quantitative comparison with the lattice results is done for the SU(3) gluon plasma and for the QGP with dynamical quarks. Our analysis advocates a negative value of the bag constant B.

  9. SPHERES Maintenance Run

    NASA Image and Video Library

    2016-06-30

    iss048e017435 (6/30/2016) --- Commander Jeff Williams monitors bowling ball-sized internal satellites known as SPHERES (Synchronized Position Hold, Engage, Reorient, Experimental Satellites) during a maintenance run in the Japanese Kibo Laboratory Module.

  10. Associated heavy quarks pair production with Higgs as a tool for a search for non-perturbative effects of the electroweak interaction at the LHC

    NASA Astrophysics Data System (ADS)

    Arbuzov, B. A.; Zaitsev, I. V.

    2017-09-01

    Assuming an existence of the anomalous triple electro-weak bosons interaction being defined by coupling constant λ we calculate its contribution to interactions of the Higgs with pairs of heavy particles. Bearing in mind experimental restrictions - 0.011 < λ < 0.011 we present results for possible effects in processes p p →W+W- H , p p →W+ ZH , p p →W- ZH , p p → t bar tH, pp → b bar bH. Effects could be significant with negative sign of λ in associated heavy quarks t , b pairs production with the Higgs. In calculations we rely on results of the non-perturbative approach to a spontaneous generation of effective interactions, which defines the form-factor of the three-boson anomalous interaction.

  11. Run 16, eIPM Summary

    SciTech Connect

    Connolly, R.; Dawson, C.; Jao, S.; Schoefer, V.; Tepikian, S.

    2016-08-05

    Three problems with the eIPMs were corrected during the 2015 summer shutdown. These involved ac coupling and 'negative profiles', detector 'dead zone' created by biasing, and gain control on ramp. With respect to Run 16, problems dealt with included gain depletion on horizontal MCP and rf pickup on profile signals; it was found that the MCP was severely damaged over part of the aperture. Various corrective measures were applied. Some results of these measured obtained during Run 16 are shown. At the end of Run 16 there was a three-­day beam run to study polarized proton beams in the AGS. Attempts to minimize beam injection errors which increase emittance by using the eIPMs to measure the contribution of injection mismatch to the AGS output beam emittance are recounted. .

  12. 84. AERIAL VIEW OF SPOUT RUN ARCH BRIDGE, SPOUT RUN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    84. AERIAL VIEW OF SPOUT RUN ARCH BRIDGE, SPOUT RUN BRIDGE WESTBOUND AND SPOUT RUN PARKWAY CULVERT LOOKING SOUTH. - George Washington Memorial Parkway, Along Potomac River from McLean to Mount Vernon, VA, Mount Vernon, Fairfax County, VA

  13. 87. AERIAL VIEW OF SPOUT RUN ARCH BRIDGE, SPOUT RUN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    87. AERIAL VIEW OF SPOUT RUN ARCH BRIDGE, SPOUT RUN BRIDGE WESTBOUND AND SPOUT RUN PARKWAY CULVERT LOOKING SOUTHWEST. - George Washington Memorial Parkway, Along Potomac River from McLean to Mount Vernon, VA, Mount Vernon, Fairfax County, VA

  14. 86. AERIAL VIEW OF SPOUT RUN ARCH BRIDGE, SPOUT RUN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    86. AERIAL VIEW OF SPOUT RUN ARCH BRIDGE, SPOUT RUN BRIDGE WESTBOUND AND SPOUT RUN PARKWAY CULVERT LOOKING SOUTH. - George Washington Memorial Parkway, Along Potomac River from McLean to Mount Vernon, VA, Mount Vernon, Fairfax County, VA

  15. Prevention of running injuries.

    PubMed

    Fields, Karl B; Sykes, Jeannie C; Walker, Katherine M; Jackson, Jonathan C

    2010-01-01

    Evidence for preventive strategies to lessen running injuries is needed as these occur in 40%-50% of runners on an annual basis. Many factors influence running injuries, but strong evidence for prevention only exists for training modification primarily by reducing weekly mileage. Two anatomical factors - cavus feet and leg length inequality - demonstrate a link to injury. Weak evidence suggests that orthotics may lessen risk of stress fracture, but no clear evidence proves they will reduce the risk of those athletes with leg length inequality or cavus feet. This article reviews other potential injury variables, including strength, biomechanics, stretching, warm-up, nutrition, psychological factors, and shoes. Additional research is needed to determine whether interventions to address any of these will help prevent running injury.

  16. Quark dynamics and pion-nucleon coupling

    NASA Astrophysics Data System (ADS)

    Weise, W.; Werner, E.

    1981-05-01

    In the framework of nonperturbative QCD phenomenology we discuss: (1) The elementary process for the creation of color-singlet qq-pairs inside a hadron. (2) The interaction of the qq-pair with the surrounding quark-gluon medium. An important consequence of these discussions is that meson emission takes place preferentially, if the primary qq-pair is created in the surface region of the hadron. For the case of pseudoscalar coupling we employ PCAC to obtain the coupling of the qq-pair to the pion. The resulting form and coupling strength of the πNN vertex is consistent with the phenomenological OPEP.

  17. The Art of Running

    ERIC Educational Resources Information Center

    Brown, Jill Harris

    2007-01-01

    Every year, the Parent-Teacher Association of Ferndale Elementary School in Atlanta, Georgia sponsors a fun road race for the students, teachers, families, and community. This annual event has inspired the author to develop the Running and Art project to show off her students' art and squeeze in a little art history, too. In this article, the…

  18. The Art of Running

    ERIC Educational Resources Information Center

    Brown, Jill Harris

    2007-01-01

    Every year, the Parent-Teacher Association of Ferndale Elementary School in Atlanta, Georgia sponsors a fun road race for the students, teachers, families, and community. This annual event has inspired the author to develop the Running and Art project to show off her students' art and squeeze in a little art history, too. In this article, the…

  19. Running Wheel for Earthworms

    PubMed Central

    Wilson, W. Jeffrey; Johnson, Brandon A.

    2016-01-01

    We describe the construction and use of a running wheel responsive to the movement of the earthworm. The wheel employs readily available, inexpensive components and is easily constructed. Movement of the wheel can be monitored visually or via standard behavioral laboratory computer interfaces. Examples of data are presented, and possibilities for use in the teaching classroom are discussed. PMID:27385934

  20. Who Runs Our Universities?

    ERIC Educational Resources Information Center

    Watson, David

    2012-01-01

    Inside the academy there is a cultural perspective that it should run itself, in the sense that "business as usual" should be done with no one's hands obviously on the levers. This theory reaches its high point in the "self-government" of Oxford and Cambridge colleges. In this article, the author explores the question,…

  1. Who Runs Our Universities?

    ERIC Educational Resources Information Center

    Watson, David

    2012-01-01

    Inside the academy there is a cultural perspective that it should run itself, in the sense that "business as usual" should be done with no one's hands obviously on the levers. This theory reaches its high point in the "self-government" of Oxford and Cambridge colleges. In this article, the author explores the question,…

  2. Nonperturbative renormalization of quark bilinear operators and B{sub K} using domain wall fermions

    SciTech Connect

    Aoki, Y.; Dawson, C.; Boyle, P. A.; Tweedie, R. J.; Christ, N. H.; Li, S.; Mawhinney, R. D.; Donnellan, M. A.; Juettner, A.; Sachrajda, C. T.; Izubuchi, T.; Noaki, J.; Soni, A.; Yamaguchi, A.

    2008-09-01

    We present a calculation of the renormalization coefficients of the quark bilinear operators and the K-K mixing parameter B{sub K}. The coefficients relating the bare lattice operators to those in the RI/MOM scheme are computed nonperturbatively and then matched perturbatively to the MS scheme. The coefficients are calculated on the RBC/UKQCD 2+1 flavor dynamical lattice configurations. Specifically we use a 16{sup 3}x32 lattice volume, the Iwasaki gauge action at {beta}=2.13 and domain wall fermions with L{sub s}=16.

  3. Challenges in the extraction of TMDs from SIDIS data: perturbative vs non-perturbative aspects

    SciTech Connect

    Boglione, Mariaelena; Gonzalez Hernandez, Jose O.; Melis, Stefano; Prokudin, Alexey

    2015-09-01

    We present our recent results on the study of the Semi-Inclusive Deep Inelastic Scattering (SIDIS) cross section as a function of the transverse momentum, qT. Using the Collins-Soper-Sterman (CSS) formalism, we study the matching between the region where fixed-order perturbative QCD can successfully be applied and the region where soft gluon resummation is necessary. We find that the commonly used prescription of matching through the so-called Y-factor cannot be applied in the SIDIS kinematical configurations we examine. We comment on the impact that the nonperturbative component has even at relatively high energies.

  4. Absorption-edge singularities for a nonequilibrium Fermi sea. III. Determinantal nonperturbative theory

    SciTech Connect

    Tanguy, C.; Combescot, M.

    1995-10-15

    The nonperturbative solution to the problem of threshold singularities for a ({mu}{sub 1},{mu}{sub 2}) nonequilibrium Fermi sea is obtained using the determinantal method of Ohtaka and Tanabe. The critical exponents of the absorption power-law behavior we find agree with those estimated from the perturbative treatment of the problem given in papers I and II. A family of possibly diverging singularities is found at energies {mu}{sub 2}+{ital n}({mu}{sub 1}{minus}{mu}{sub 2}), for {ital n}{ge}1.

  5. Nonperturbative electromagnetic muon-pair production with capture in peripheral relativistic heavy-ion collisions

    SciTech Connect

    Wells, J.C. Vanderbilt Univ., Nashville, TN . Dept. of Physics and Astronomy); Oberacker, V.E.; Umar, A.S. . Dept. of Physics and Astronomy); Bottcher, C.; Strayer, M.R.; Wu, J.S. )

    1991-01-01

    We discuss preliminary calculations of impact-parameter-dependent probabilities and cross sections for muon-pair production with capture of the negative muon into the K-shell of the target caused by the time-dependent electromagnetic fields generated in peripheral relativistic heavy-ion collisions. Our approach is nonperturbative in that we calculate probabilities by solving the time-dependent Dirac equation on a three-dimensional Cartesian lattice using the basis-spline collocation method. Use of the axial gauge for the electromagnetic potentials produces an interaction easier to implement on the lattice than the Lorentz gauge. 19 refs., 5 figs.

  6. Non-perturbative scalar potential inspired by type IIA strings on rigid CY

    NASA Astrophysics Data System (ADS)

    Alexandrov, Sergei; Ketov, Sergei V.; Wakimoto, Yuki

    2016-11-01

    Motivated by a class of flux compactifications of type IIA strings on rigid Calabi-Yau manifolds, preserving N = 2 local supersymmetry in four dimensions, we derive a non-perturbative potential of all scalar fields from the exact D-instanton corrected metric on the hypermultiplet moduli space. Applying this potential to moduli stabilization, we find a discrete set of exact vacua for axions. At these critical points, the stability problem is decoupled into two subspaces spanned by the axions and the other fields (dilaton and Kähler moduli), respectively. Whereas the stability of the axions is easily achieved, numerical analysis shows instabilities in the second subspace.

  7. Bound states of the ϕ4 model via the nonperturbative renormalization group

    NASA Astrophysics Data System (ADS)

    Rose, F.; Benitez, F.; Léonard, F.; Delamotte, B.

    2016-06-01

    Using the nonperturbative renormalization group, we study the existence of bound states in the symmetry-broken phase of the scalar ϕ4 theory in all dimensions between two and four and as a function of the temperature. The accurate description of the momentum dependence of the two-point function, required to get the spectrum of the theory, is provided by means of the Blaizot-Méndez-Galain-Wschebor approximation scheme. We confirm the existence of a bound state in dimension three, with a mass within 1% of previous Monte-Carlo and numerical diagonalization values.

  8. Towards a nonperturbative foundation of the dipole picture: I. Functional methods

    NASA Astrophysics Data System (ADS)

    Ewerz, Carlo; Nachtmann, Otto

    2007-07-01

    This is the first of two papers in which we study real and virtual photon-proton scattering in a nonperturbative framework. We classify different contributions to this process and identify the leading contributions at high energies. We then study the renormalisation of the photon-quark-antiquark vertex that occurs in the leading contributions. We find something like the dipole picture in one of these contributions but also find two correction terms which can potentially become large at small photon virtualities. In the second paper we will discuss the additional approximations and assumptions that are necessary to obtain the dipole model of high energy scattering from the results found here.

  9. Quantizing dilatonic black holes. Towards nonperturbative canonical quantization of the CGHS model.

    NASA Astrophysics Data System (ADS)

    Varadarajan, M.

    Motivated by the search for a nonperturbative quantization, the author casts the Callan-Giddings-Harvey-Strominger (CGHS) model of dilatonic black holes into a Hamiltonian framework. By making transformations to new "embedding" variables, he maps the model into that of a parametrized scalar field propagating on a fixed flat 1+1 background spacetime. The description in terms of the new variables is thus more amenable to quantization. Issues of asymptotics and boundary terms are dealt with systematically. This work has been done in collaboration with K. Kuchař (Univ of Utah) and J. Romano (Univ of Wisconsin-Milwaukee).

  10. A new, analytic, non-perturbative, gauge-invariant formulation of realistic QCD

    NASA Astrophysics Data System (ADS)

    Fried, H. M.; Grandou, T.; Gabellini, Y.; Sheu, Y.-M.

    2012-09-01

    This Formulation [1], [2], [3] is New, in the sense that it is less than 3 years old. But it could have been done decades ago, since the input information existed, but was overlooked. It is Analytic in the sense that physically-reasonable approximations can be estimated with paper and pencil; and exact amplitudes can be calculated as Meijer G-functions of various orders. It is Non-Perturbative in the sense that sums over all possible gluon exchanges between any pair of quarks and/or antiquarks, including cubic and quartic gluon interactions, are exactly performed. These multiple gluon exchanges combine into "Gluon Bundles" (GBs), as sums over Feynman graphs with finite numbers of exchanged gluons are replaced by "Bundle Graphs". In effect, gluons disappear from the formalism, and GBs remain as the effective carrier of all interactions between quark lines. A simple re-arrangement of the Schwinger/Symanzik functional solution for the Generating Functional of QCD - a rearrangement possible in QCD but not in QED - produces a formal statement of Gauge-Invariance, even though the formulation contains gauge-dependent gluon propagators. After the non-perturbative sums produce GBs, one sees explicit cancelation of all gauge-dependent gluon propagators; gauge-invariance is achieved as gauge-independence. A new insight into Realistic QCD appears in the non-perturbative domain, because quarks do not have individual asymptotic states; they are always asymptotically bound, and their transverse coordinates cannot, in principle, be measured exactly. "Transverse Imprecision" is introduced into the basic Lagrangian, and quark-binding potentials for the construction of mesons and nucleons can then be defined and evaluated. And the greatest surprise of all: A new, non-perturbative property appears, called Effective Locality, with the result that all functional integrals reduce to (a few) sets of ordinary integrals, easy to estimate approximately, or calculate on a desk-top computer. A

  11. Finite temperature QCD with two flavors of nonperturbatively improved Wilson fermions

    SciTech Connect

    Bornyakov, V.G.; Chernodub, M.N.; Ichie, H.; Mori, Y.; Nakamura, Y.; Suzuki, T.; Koma, Y.; Polikarpov, M.I.; Uvarov, P.V.; Veselov, A.I.; Schierholz, G.; Slavnov, A. A.; Stueben, H.

    2005-06-01

    We study QCD with two flavors of nonperturbatively improved Wilson fermions at finite temperature on the 16{sup 3}8 lattice. We determine the transition temperature at lattice spacing as small as a{approx}0.12 fm, and study string breaking below the finite temperature transition. We find that the static potential can be fitted by a two-state ansatz, including a string state and a two-meson state. We investigate the role of Abelian monopoles at finite temperature.

  12. A new, analytic, non-perturbative, gauge-invariant formulation of realistic QCD

    SciTech Connect

    Fried, H. M.; Grandou, T.; Gabellini, Y.; Sheu, Y.-M.

    2012-09-26

    This Formulation [1], [2], [3] is New, in the sense that it is less than 3 years old. But it could have been done decades ago, since the input information existed, but was overlooked. It is Analytic in the sense that physically-reasonable approximations can be estimated with paper and pencil; and exact amplitudes can be calculated as Meijer G-functions of various orders. It is Non-Perturbative in the sense that sums over all possible gluon exchanges between any pair of quarks and/or antiquarks, including cubic and quartic gluon interactions, are exactly performed. These multiple gluon exchanges combine into 'Gluon Bundles' (GBs), as sums over Feynman graphs with finite numbers of exchanged gluons are replaced by {sup B}undle Graphs{sup .} In effect, gluons disappear from the formalism, and GBs remain as the effective carrier of all interactions between quark lines. A simple re-arrangement of the Schwinger/Symanzik functional solution for the Generating Functional of QCD - a rearrangement possible in QCD but not in QED - produces a formal statement of Gauge-Invariance, even though the formulation contains gauge-dependent gluon propagators. After the non-perturbative sums produce GBs, one sees explicit cancelation of all gauge-dependent gluon propagators; gauge-invariance is achieved as gauge-independence. A new insight into Realistic QCD appears in the non-perturbative domain, because quarks do not have individual asymptotic states; they are always asymptotically bound, and their transverse coordinates cannot, in principle, be measured exactly. 'Transverse Imprecision' is introduced into the basic Lagrangian, and quark-binding potentials for the construction of mesons and nucleons can then be defined and evaluated. And the greatest surprise of all: A new, non-perturbative property appears, called Effective Locality, with the result that all functional integrals reduce to (a few) sets of ordinary integrals, easy to estimate approximately, or calculate on a desk

  13. A Continuously Running High-Rate GEM-TPC for P¯ANDA

    NASA Astrophysics Data System (ADS)

    Böhmer, F. V.; Angerer, H.; Dørheim, S.; Höppner, C.; Ketzer, B.; Konorov, I.; Neubert, S.; Paul, S.; Vandenbroucke, M.; Zhang, X.; Berger, M.; Cusanno, F.; Fabbietti, L.; Lalik, R.; Beck, R.; Kaiser, D.; Lang, M.; Schmitz, R.; Walther, D.; Winnebeck, A.; Zenke, F.; Arora, R.; Averbeckt, R.; Hehner, J.; Herrmannt, N.; Kleipa, V.; Kunkel, J.; Leifelst, Y.; Mladen, K.; Schmidt, C.; Schwab, S.; Soyk, D.; Voss, B.; Voss, J.; Weinert, J.; Zmeskal, J.

    2011-06-01

    The P¯ANDA fixed target experiment planned at FAIR will investigate fundamental questions of non-perturbative QCD. It makes use of a cooled antiproton beam (momentum: 1.5 to 15 GeV/c) and will reach luminosities of up to 2ṡ10 cm s, yielding a p¯p-annihilation rate of 2ṡ10 s. One option for the central tracker of P¯ANDA is a cylindrical, ungated, continuously running TPC with GEM-based gas amplification stage.

  14. Calcaneal loading during walking and running

    NASA Technical Reports Server (NTRS)

    Giddings, V. L.; Beaupre, G. S.; Whalen, R. T.; Carter, D. R.

    2000-01-01

    PURPOSE: This study of the foot uses experimentally measured kinematic and kinetic data with a numerical model to evaluate in vivo calcaneal stresses during walking and running. METHODS: External ground reaction forces (GRF) and kinematic data were measured during walking and running using cineradiography and force plate measurements. A contact-coupled finite element model of the foot was developed to assess the forces acting on the calcaneus during gait. RESULTS: We found that the calculated force-time profiles of the joint contact, ligament, and Achilles tendon forces varied with the time-history curve of the moment about the ankle joint. The model predicted peak talocalcaneal and calcaneocuboid joint loads of 5.4 and 4.2 body weights (BW) during walking and 11.1 and 7.9 BW during running. The maximum predicted Achilles tendon forces were 3.9 and 7.7 BW for walking and running. CONCLUSIONS: Large magnitude forces and calcaneal stresses are generated late in the stance phase, with maximum loads occurring at approximately 70% of the stance phase during walking and at approximately 60% of the stance phase during running, for the gait velocities analyzed. The trajectories of the principal stresses, during both walking and running, corresponded to each other and qualitatively to the calcaneal trabecular architecture.

  15. Calcaneal loading during walking and running

    NASA Technical Reports Server (NTRS)

    Giddings, V. L.; Beaupre, G. S.; Whalen, R. T.; Carter, D. R.

    2000-01-01

    PURPOSE: This study of the foot uses experimentally measured kinematic and kinetic data with a numerical model to evaluate in vivo calcaneal stresses during walking and running. METHODS: External ground reaction forces (GRF) and kinematic data were measured during walking and running using cineradiography and force plate measurements. A contact-coupled finite element model of the foot was developed to assess the forces acting on the calcaneus during gait. RESULTS: We found that the calculated force-time profiles of the joint contact, ligament, and Achilles tendon forces varied with the time-history curve of the moment about the ankle joint. The model predicted peak talocalcaneal and calcaneocuboid joint loads of 5.4 and 4.2 body weights (BW) during walking and 11.1 and 7.9 BW during running. The maximum predicted Achilles tendon forces were 3.9 and 7.7 BW for walking and running. CONCLUSIONS: Large magnitude forces and calcaneal stresses are generated late in the stance phase, with maximum loads occurring at approximately 70% of the stance phase during walking and at approximately 60% of the stance phase during running, for the gait velocities analyzed. The trajectories of the principal stresses, during both walking and running, corresponded to each other and qualitatively to the calcaneal trabecular architecture.

  16. Does Addiction Run in Families?

    MedlinePlus

    ... Addiction Run in Families? Does Addiction Run in Families? Listen PDF: EasyToRead_WhatIsAddiction_Final_012017.pdf Addiction ... Español English Español "Heart disease runs in some families. Addiction runs in ours." ©istock.com/ Antonio_Diaz ...

  17. Nonperturbative O(a) improvement of the Wilson quark action with the renormalization-group-improved gauge action using the Schroedinger functional method

    SciTech Connect

    Aoki, S.; Takeda, S.; Taniguchi, Y.; Fukugita, M.; Hashimoto, S.; Kaneko, T.; Yamada, N.; Ishikawa, K-I.; Okawa, M.; Ishizuka, N.; Iwasaki, Y.; Kanaya, K.; Kuramashi, Y.; Ukawa, A.; Yoshie, T.; Tsutsui, N.

    2006-02-01

    We perform a nonperturbative determination of the O(a)-improvement coefficient c{sub SW} and the critical hopping parameter {kappa}{sub c} for N{sub f}=3, 2, and 0 flavor QCD with the (RG) renormalization-group-improved gauge action using the Schroedinger functional method. In order to interpolate c{sub SW} and {kappa}{sub c} as a function of the bare coupling, a wide range of {beta} from the weak coupling region to the moderately strong coupling points used in large-scale simulations is studied. Corrections at finite lattice size of O(a/L) turned out to be large for the RG-improved gauge action, and hence we make the determination at a size fixed in physical units using a modified improvement condition. This enables us to avoid O(a) scaling violations which would remain in physical observables if c{sub SW} determined for a fixed lattice size L/a is used in numerical simulations.

  18. Nonperturbative linked-cluster expansions in long-range ordered quantum systems

    NASA Astrophysics Data System (ADS)

    Ixert, Dominik; Schmidt, Kai Phillip

    2016-11-01

    We introduce a generic scheme to perform nonperturbative linked cluster expansions in long-range ordered quantum phases. Clusters are considered to be surrounded by an ordered reference state leading to effective edge fields in the exact diagonalization on clusters, which break the associated symmetry of the ordered phase. Two approaches, based either on a self-consistent solution of the order parameter or on minimal sensitivity with respect to the ground-state energy per site, are formulated to find the optimal edge field in each NLCE order. Furthermore, we investigate the scaling behavior of the NLCE data sequences towards the infinite-order limit. We apply our scheme to gapped and gapless ordered phases of XXZ Heisenberg models on various lattices and for spins 1/2 and 1 using several types of cluster expansions ranging from a full-graph decomposition, rectangular clusters, up to more symmetric square clusters. It is found that the inclusion of edge fields allows to regularize nonperturbative linked-cluster expansions in ordered phases yielding convergent data sequences. This includes the long-range spin-ordered ground state of the spin-1/2 and spin-1 Heisenberg model on the square and triangular lattice as well as the trimerized valence bond crystal of the spin-1 Heisenberg model on the kagome lattice.

  19. Nonperturbative landscape of the Mott-Hubbard transition: Multiple divergence lines around the critical endpoint

    NASA Astrophysics Data System (ADS)

    Schäfer, T.; Ciuchi, S.; Wallerberger, M.; Thunström, P.; Gunnarsson, O.; Sangiovanni, G.; Rohringer, G.; Toschi, A.

    2016-12-01

    We analyze the highly nonperturbative regime surrounding the Mott-Hubbard metal-to-insulator transition (MIT) by means of dynamical mean field theory (DMFT) calculations at the two-particle level. By extending the results of Schäfer et al. [Phys. Rev. Lett. 110, 246405 (2013), 10.1103/PhysRevLett.110.246405] we show the existence of infinitely many lines in the phase diagram of the Hubbard model where the local Bethe-Salpeter equations, and the related irreducible vertex functions, become singular in the charge as well as the particle-particle channel. By comparing our numerical data for the Hubbard model with analytical calculations for exactly solvable systems of increasing complexity [disordered binary mixture (BM), Falicov-Kimball (FK), and atomic limit (AL)], we have (i) identified two different kinds of divergence lines; (ii) classified them in terms of the frequency structure of the associated singular eigenvectors; and (iii) investigated their relation to the emergence of multiple branches in the Luttinger-Ward functional. In this way, we could distinguish the situations where the multiple divergences simply reflect the emergence of an underlying, single energy scale ν* below which perturbation theory is no longer applicable, from those where the breakdown of perturbation theory affects, not trivially, different energy regimes. Finally, we discuss the implications of our results on the theoretical understanding of the nonperturbative physics around the MIT and for future developments of many-body algorithms applicable in this regime.

  20. Nonperturbative determination of improvement coefficients using coordinate space correlators in Nf=2 +1 lattice QCD

    NASA Astrophysics Data System (ADS)

    Korcyl, Piotr; Bali, Gunnar S.

    2017-01-01

    We determine quark mass dependent order a improvement terms of the form bJa m for nonsinglet scalar, pseudoscalar, vector and axialvector currents using correlators in coordinate space on a set of Coordinated Lattice Simulations ensembles. These have been generated employing nonperturbatively improved Wilson fermions and the tree-level Lüscher-Weisz gauge action at β =3.4 , 3.46, 3.55 and 3.7, corresponding to lattice spacings ranging from a ≈0.085 fm down to 0.05 fm. In the Nf=2 +1 flavor theory two types of improvement coefficients exist: bJ, proportional to nonsinglet quark mass combinations, and b¯J (or b˜J), proportional to the trace of the quark mass matrix. Combining our nonperturbative determinations with perturbative results, we quote Padé approximants parametrizing the bJ improvement coefficients within the above window of lattice spacings. We also give preliminary results for b˜J at β =3.4 .

  1. WRF nature run

    NASA Astrophysics Data System (ADS)

    Michalakes, J.; Hacker, J.; Loft, R.; McCracken, M. O.; Snavely, A.; Wright, N. J.; Spelce, T.; Gorda, B.; Walkup, R.

    2008-07-01

    The Weather Research and Forecast (WRF) model is a model of the atmosphere for mesoscale research and operational numerical weather prediction (NWP). A petascale problem for WRF is a nature run that provides very high-resolution 'truth' against which more coarse simulations or perturbation runs may be com-pared for purposes of studying predictability, stochastic parameterization, and fundamental dynamics. We carried out a nature run involving an idealized high resolution rotating fluid on the hemisphere, at a size and resolution never before attempted, and used it to investigate scales that span the k-3 to k-5/3 kinetic energy spectral transition, via simulations. We used up to 15,360 processors of the New York Blue IBM BG/L machine at Stony Brook Uni-versity and Brookhaven National Laboratory. The grid we employed has 4486 by 4486 horizontal grid points and 101 vertical levels (2 billion cells) at 5km resolution; this is 32 times larger than the previously largest 63 million cell 2.5km resolution WRF CONUS benchmark [10]). To solve a problem of this size, we worked through issues of parallel I/O and scalability and employed more processors than have ever been used in a WRF run. We achieved a sustained 3.4 Tflop/s on the New York Blue sys-tem, inputting and then generating an enormous amount of data to produce a scientifically meaningful result. More than 200 GB of data was input to initialize the run, which then generated output datasets of 40 GB each simulated hour. The cost of output was considered a key component of our investigation. Then we ran the same problem on more than 12K processors of the XT4 system at NERSC and achieved 8.8 Tflop/s. Our primary result however is not just scalability and a high Tflop/s number, but capture of atmosphere features never before represented by simulation, and taking an important step towards understanding weather predict-ability at high resolution.

  2. Casimir effect: running Newton constant or cosmological term

    NASA Astrophysics Data System (ADS)

    Polonyi, Janos; Regos, Eniko

    2006-01-01

    We argue that the instability of Euclidean Einstein gravity is an indication that the vacuum is non-perturbative and contains a condensate of the metric tensor in a manner reminiscent of Yang Mills theories. As a simple step toward the characterization of such a vacuum the value of the 1-loop effective action is computed for Euclidean de Sitter spaces as a function of the curvature when the unstable conformal modes are held fixed. Two phases are found, one where the curvature is large and gravitons should be confined and another one which appears to be weakly coupled and tends to be flat. The induced cosmological constant is positive or negative in the strongly or weakly curved phase, respectively. The relevance of the Casimir effect in understanding the UV sensitivity of gravity is pointed out.

  3. Run II luminosity progress

    SciTech Connect

    Gollwitzer, K.; /Fermilab

    2007-06-01

    The Fermilab Tevatron Collider Run II program continues at the energy and luminosity frontier of high energy particle physics. To the collider experiments CDF and D0, over 3 fb{sup -1} of integrated luminosity has been delivered to each. Upgrades and improvements in the Antiproton Source of the production and collection of antiprotons have led to increased number of particles stored in the Recycler. Electron cooling and associated improvements have help make a brighter antiproton beam at collisions. Tevatron improvements to handle the increased number of particles and the beam lifetimes have resulted in an increase in luminosity.

  4. On a strong coupling property of QCD

    NASA Astrophysics Data System (ADS)

    Grandou, T.

    2017-03-01

    The fermionic Green's functions of QCD exhibit an unexpected property of effective locality, which appears to be exact, involving no approximation. In the limit of strong coupling, and at eikonal and quenching approximations (where this property was first discovered), effective locality implies a dependence of non-perturbative fermionic Green's functions on the full algebraic content of the rank 2-SUc(3) color algebra. At variance with Perturbation Theory and a variety of non-perturbative approaches also, C3-dependences show up, where C3 stands for the second, trilinear Casimir invariant of SUc(3). These dependences are sub-leading in magnitude and seem to comply with the maximally allowed departures from the pure C2 behaviours advocated by lattice numerical estimates.

  5. 198. SPOUT RUN ARCH BRIDGE AND SPOUT RUN WESTBOUND BRIDGE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    198. SPOUT RUN ARCH BRIDGE AND SPOUT RUN WESTBOUND BRIDGE FROM POTOMAC RIVER LOOKING SOUTHWEST. - George Washington Memorial Parkway, Along Potomac River from McLean to Mount Vernon, VA, Mount Vernon, Fairfax County, VA

  6. Scale dependencies of proton spin constituents with a nonperturbative αs

    NASA Astrophysics Data System (ADS)

    Jia, Shaoyang; Huang, Feng

    2012-11-01

    By introducing the contribution from dynamically generated gluon mass, we present a brand new parametrized form of QCD beta function to get an inferred limited running behavior of QCD coupling constant αs. This parametrized form is regarded as an essential factor to determine the scale dependencies of the proton spin constituents at the very low scale. In order to compare with experimental results directly, we work within the gauge-invariant framework to decompose the proton spin. Utilizing the updated next-to-next-leading-order evolution equations for angular momentum observables within a modified minimal subtraction scheme, we indicate that gluon contribution to proton spin cannot be ignored. Specifically, by assuming asymptotic limits of the total quark/gluon angular momentum valid, respectively, the scale dependencies of quark angular momentum Jq and gluon angular momentum Jg down to Q2˜1GeV2 are presented, which are comparable with the preliminary analysis of deeply virtual Compton scattering experiments by HERMES and JLab. After solving scale dependencies of quark spin ΔΣq, orbital angular momenta of quarks Lq are given by subtraction, presenting a holistic picture of proton spin partition within up and down quarks at a low scale.

  7. Two topics in nonperturbative lattice field theories: The U(1) quantum link model and perfect actions for scalar theories

    NASA Astrophysics Data System (ADS)

    Tsapalis, Antonios S.

    This thesis deals with two topics in lattice field theories. In the first part we discuss aspects of renormalization group flow and non-perturbative improvement of actions for scalar theories regularized on a lattice. We construct a perfect action, an action which is free of lattice artifacts, for a given theory. It is shown how a good approximation to the perfect action-referred to as classically perfect-can be constructed based on a well-defined blocking scheme for the O(3) non-linear σ-model. We study the O(N) non- linear σ-model in the large-N limit and derive analytically its perfect action. This action is applied to the O(3) model on a square lattice. The Wolff cluster algorithm is used to simulate numerically the system. We perform scaling tests and discuss the scaling properties of the large- N inspired perfect action as opposed to the standard and the classically perfect action. In the second part we present a new formulation for a quantum field theory with Abelian gauge symmetry. A Hamiltonian is constructed on a four-dimensional Euclidean space-time lattice which is invariant under local transformations. The model is formulated as a 5- dimensional path integral of discrete variables. We argue that dimensional reduction will allow us to study the behavior of the standard compact U(1) gauge theory in 4-d. Based on the idea of the loop- cluster algorithm for quantum spins, we present the construction of a flux-cluster algorithm for the U(1) quantum link model for the spin-1/2 quantization of the electric flux. It is shown how improved estimators for Wilson loop expectation values can be defined. This is important because the Wilson loops are traditionally used to identify confining and Coulomb phases in gauge theories. Our study indicates that the spin-1/2 U(1) quantum link model is strongly coupled for all bare coupling values we examined. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)

  8. PDU Run 10

    SciTech Connect

    Not Available

    1981-09-01

    PDU Run 10, a 46-day H-Coal syncrude mode operation using Wyodak coal, successfully met all targeted objectives, and was the longest PDU operation to date in this program. Targeted coal conversion of 90 W % was exceeded with a C/sub 4/-975/sup 0/F distillate yield of 43 to 48 W %. Amocat 1A catalyst was qualified for Pilot Plant operation based on improved operation and superior performance. PDU 10 achieved improved yields and lower hydrogen consumption compared to PDU 6, a similar operation. High hydroclone efficiency and high solids content in the vacuum still were maintained throughout the run. Steady operations at lower oil/solids ratios were demonstrated. Microautoclave testing was introduced as an operational aid. Four additional studies were successfully completed during PDU 10. These included a catalyst tracer study in conjunction with Sandia Laboratories; tests on letdown valve trims for Battelle; a fluid dynamics study with Amoco; and special high-pressure liquid sampling.

  9. Nonperturbative charming penguin contributions to isospin asymmetries in radiative B decays

    SciTech Connect

    Kim, Chul; Mehen, Thomas; Leibovich, Adam K.

    2008-09-01

    Recent experimental data on the radiative decays B{yields}V{gamma}, where V is a light vector meson, find small isospin violation in B{yields}K*{gamma} while isospin asymmetries in B{yields}{rho}{gamma} are of order 20%, with large uncertainties. Using soft-collinear effective theory, we calculate isospin asymmetries in these radiative B decays up to O(1/m{sub b}), also including O(v{alpha}{sub s}) contributions from nonperturbative charming penguins (NPCP). In the absence of NPCP contributions, the theoretical predictions for the asymmetries are a few percent or less. Including the NPCP can significantly increase the isospin asymmetries for both B{yields}V{gamma} modes. We also consider the effect of the NPCP on the branching ratio and CP asymmetries in B{sup {+-}}{yields}V{sup {+-}}{gamma}.

  10. Trace of nonperturbative charm content of the nucleon on Z + c-jet production

    NASA Astrophysics Data System (ADS)

    Rostami, S.; Khorramian, A.

    2017-06-01

    We perform a comparison of the impact of different intrinsic charm (IC) models, based on the prediction of the differential cross-sections of Z-boson and c-jet production in pp collision. It is shown that regardless of choosing the model, considering nonperturbative intrinsic charm component increases the magnitude of the cross-section when the Z transverse momentum grows or at large rapidity (y) of the Z. Moreover, to evaluate the effect of different parton distribution functions (PDFs), we also compare the results of two PDF sets in prediction of production Z + c-jet in pp at a center-of-mass energy of 13 TeV with taking into account the intrinsic charm contribution in the proton. It is shown that the various PDF sets give some difference in the description of the Z + c-jet cross-section.

  11. Gravity waves from the nonperturbative decay of condensates along supersymmetric flat directions.

    PubMed

    Dufaux, Jean-François

    2009-07-24

    Nonperturbative effects may lead to an explosive decay of flat direction condensates in supersymmetric theories. We confirm the efficiency of this process with lattice simulations: After only one to five rotations of the condensates in their complex plane, most of their energy is converted into inhomogeneous fluctuations. This generates a gravitational wave background, which depends on the inflaton sector and falls in the hertz-kilohertz frequency range today. These gravity waves can be observable by upcoming experiments such as Advanced LIGO and depend crucially on (i) the initial vacuum expectation value of flat directions when they start to oscillate, (ii) their soft supersymmetry-breaking mass, and (iii) the reheat temperature of the Universe. This signal could open a new observational window on inflation and low-energy supersymmetry.

  12. Modeling a nonperturbative spinor vacuum interacting with a strong gravitational wave

    NASA Astrophysics Data System (ADS)

    Dzhunushaliev, Vladimir; Folomeev, Vladimir

    2015-07-01

    We consider the propagation of strong gravitational waves interacting with a nonperturbative vacuum of spinor fields. To described the latter, we suggest an approximate model. The corresponding Einstein equation has the form of the Schrödinger equation. Its gravitational-wave solution is analogous to the solution of the Schrödinger equation for an electron moving in a periodic potential. The general solution for the periodic gravitational waves is found. The analog of the Kronig-Penney model for gravitational waves is considered. It is shown that the suggested gravitational-wave model permits the existence of weak electric charge and current densities concomitant with the gravitational wave. Based on this observation, a possible experimental verification of the model is suggested.

  13. Comparison of Strategies for Non-perturbing Labeling of α-Synuclein to Study Amyloidogenesis

    PubMed Central

    Haney, Conor M.; Wissner, Rebecca F.; Warner, John B.; Wang, Yanxin J.; Ferrie, John J.; Covell, Dustin; Karpowicz, Richard J.; Lee, Virginia M.-Y.

    2016-01-01

    Characterization of the amyloidogenic Parkinson’s Disease protein α-synuclein (αS) has proven difficult due to its structural plasticity. Here, we present a number of complementary methods to site-specifically introduce fluorescent probes to examine αS fibril formation and cellular uptake. By using various combinations of conventional Cys modification, amber codon suppression, transferase mediated N-terminal modification, and native chemical ligation, several variants of singly- and doubly-labeled αS were produced. We validated the nonperturbative nature of the label by a combination of in vitro aggregation kinetics measurements and imaging of the resulting fibrils. The labeled αS can then be used to monitor conformational changes during fibril formation or cellular uptake of αS fibrils in models of disease propagation. PMID:26695131

  14. Suppression of Tritium Retention in Remote Areas of ITER by Nonperturbative Reactive Gas Injection

    SciTech Connect

    Tabares, F. L.; Ferreira, J. A.; Ramos, A.; Rooij, G. van; Westerhout, J.; Al, R.; Rapp, J.; Drenik, A.; Mozetic, M.

    2010-10-22

    A technique based on reactive gas injection in the afterglow region of the divertor plasma is proposed for the suppression of tritium-carbon codeposits in remote areas of ITER when operated with carbon-based divertor targets. Experiments in a divertor simulator plasma device indicate that a 4 nm/min deposition can be suppressed by addition of 1 Pa{center_dot}m{sup 3} s{sup -1} ammonia flow at 10 cm from the plasma. These results bolster the concept of nonperturbative scavenger injection for tritium inventory control in carbon-based fusion plasma devices, thus paving the way for ITER operation in the active phase under a carbon-dominated, plasma facing component background.

  15. Nonperturbative renormalization group preserving full-momentum dependence: Implementation and quantitative evaluation

    NASA Astrophysics Data System (ADS)

    Benitez, F.; Blaizot, J.-P.; Chaté, H.; Delamotte, B.; Méndez-Galain, R.; Wschebor, N.

    2012-02-01

    We present the implementation of the Blaizot-Méndez-Wschebor approximation scheme of the nonperturbative renormalization group we present in detail, which allows for the computation of the full-momentum dependence of correlation functions. We discuss its significance and its relation with other schemes, in particular, the derivative expansion. Quantitative results are presented for the test ground of scalar O(N) theories. Besides critical exponents, which are zero-momentum quantities, we compute the two-point function at criticality in the whole momentum range in three dimensions and, in the high-temperature phase, the universal structure factor. In all cases, we find very good agreement with the best existing results.

  16. A non-perturbative analytic expression of signal amplification factor in stochastic resonance

    NASA Astrophysics Data System (ADS)

    Dhara, Asish Kumar

    2017-04-01

    We put forward a non-perturbative scheme to calculate the response of an overdamped bistable system driven by a Gaussian white noise and perturbed by a weak monochromatic force (signal) analytically. The formalism takes into account infinite number of perturbation terms of a perturbation series with amplitude of the signal as an expansion parameter. The contributions of infinite number of relaxation modes of the stochastic dynamics to the response are also taken into account in this formalism. A closed form analytic expression of the response is obtained. Only the knowledge of the first non-trivial eigenvalue and the lowest eigenfunction of the un-perturbed Fokker-Planck operator are needed to evaluate the response. The response calculated from the derived analytic expression matches fairly well with the numerical results.

  17. Non-perturbative effects of primordial curvature perturbations on the apparent value of a cosmological constant

    NASA Astrophysics Data System (ADS)

    Enea Romano, Antonio; Sanes Negrete, Sergio; Sasaki, Misao; Starobinsky, Alexei A.

    2014-06-01

    We study effects on the luminosity distance of a local inhomogeneity seeded by primordial curvature perturbations of the type predicted by the inflationary scenario and constrained by the cosmic microwave background radiation. We find that a local underdensity originated from a one, two or three standard deviations peaks of the primordial curvature perturbations field can induce corrections to the value of a cosmological constant of the order of 0.6{%},1{%},1.5{%} , respectively. These effects cannot be neglected in the precision cosmology era in which we are entering. Our results can be considered an upper bound for the effect of the monopole component of the local non-linear structure which can arise from primordial curvature perturbations and requires a fully non-perturbative relativistic treatment.

  18. Nonperturbative finite T broadening of the {rho} meson and dilepton emission in heavy-ion collisions

    SciTech Connect

    Ruppert, Joerg; Renk, Thorsten

    2005-06-01

    We study self-consistently the finite T broadening of the {rho} meson and its implications for dilepton emission in heavy-ion collisions. For this purpose finite width effects at finite temperature due to the {rho}-{pi} interaction are investigated in a self-consistent {phi}-functional approach. The temperature dependence of the {rho} meson and pion spectral functions and self-energies is discussed. The spectral functions show considerable broadening in comparison with a perturbative calculation on the one-loop level. Using these spectral functions, we make a comparison to dilepton emission data from the CERES NA49 Collaboration employing a parametrized fireball evolution model of collision. We demonstrate that these nonperturbative finite width effects are in-medium modifications relevant to the understanding of the enhancement of the low invariant mass spectrum of dileptons emitted in A-A collisions.

  19. Nonperturbative renormalization group study of the stochastic Navier-Stokes equation.

    PubMed

    Mejía-Monasterio, Carlos; Muratore-Ginanneschi, Paolo

    2012-07-01

    We study the renormalization group flow of the average action of the stochastic Navier-Stokes equation with power-law forcing. Using Galilean invariance, we introduce a nonperturbative approximation adapted to the zero-frequency sector of the theory in the parametric range of the Hölder exponent 4-2ε of the forcing where real-space local interactions are relevant. In any spatial dimension d, we observe the convergence of the resulting renormalization group flow to a unique fixed point which yields a kinetic energy spectrum scaling in agreement with canonical dimension analysis. Kolmogorov's -5/3 law is, thus, recovered for ε = 2 as also predicted by perturbative renormalization. At variance with the perturbative prediction, the -5/3 law emerges in the presence of a saturation in the ε dependence of the scaling dimension of the eddy diffusivity at ε = 3/2 when, according to perturbative renormalization, the velocity field becomes infrared relevant.

  20. Fully developed isotropic turbulence: Nonperturbative renormalization group formalism and fixed-point solution.

    PubMed

    Canet, Léonie; Delamotte, Bertrand; Wschebor, Nicolás

    2016-06-01

    We investigate the regime of fully developed homogeneous and isotropic turbulence of the Navier-Stokes (NS) equation in the presence of a stochastic forcing, using the nonperturbative (functional) renormalization group (NPRG). Within a simple approximation based on symmetries, we obtain the fixed-point solution of the NPRG flow equations that corresponds to fully developed turbulence both in d=2 and 3 dimensions. Deviations to the dimensional scalings (Kolmogorov in d=3 or Kraichnan-Batchelor in d=2) are found for the two-point functions. To further analyze these deviations, we derive exact flow equations in the large wave-number limit, and show that the fixed point does not entail the usual scale invariance, thereby identifying the mechanism for the emergence of intermittency within the NPRG framework. The purpose of this work is to provide a detailed basis for NPRG studies of NS turbulence; the determination of the ensuing intermittency exponents is left for future work.

  1. Ordered phase of the O(N) model within the nonperturbative renormalization group.

    PubMed

    Peláez, Marcela; Wschebor, Nicolás

    2016-10-01

    We analyze nonperturbative renormalization group flow equations for the ordered phase of Z_{2} and O(N) invariant scalar models. This is done within the well-known derivative expansion scheme. For its leading order [local potential approximation (LPA)], we show that not every regulator yields a smooth flow with a convex free energy and discuss for which regulators the flow becomes singular. Then we generalize the known exact solutions of smooth flows in the "internal" region of the potential and exploit these solutions to implement an improved numerical algorithm, which is much more stable than previous ones for N>1. After that, we study the flow equations at second order of the derivative expansion and analyze how and when the LPA results change. We also discuss the evolution of the field renormalization factors.

  2. Nonperturbative emergence of the Dirac fermion in a strongly correlated composite Fermi liquid

    NASA Astrophysics Data System (ADS)

    Yang, Yibin; Luo, Xi; Yu, Yue

    2017-01-01

    The classic composite fermion field theory [B. I. Halperin, P. A. Lee, and N. Read, Phys. Rev. B 47, 7312 (1993)], 10.1103/PhysRevB.47.7312 builds up an excellent framework to uniformly study important physical objects and globally explain anomalous experimental phenomena in fractional quantum Hall physics while there are also inherent weaknesses. We present a nonperturbative emergent Dirac fermion theory from this strongly correlated composite fermion field theory, which overcomes these serious long-standing shortcomings. The particle-hole symmetry of the Dirac equation resolves this particle-hole symmetry enigma in the composite fermion field theory. With the help of presented numerical data, we show that for main Jain's sequences of fractional quantum Hall effects, this emergent Dirac fermion theory in mean field approximation is most likely stable.

  3. Suppression of Tritium Retention in Remote Areas of ITER by Nonperturbative Reactive Gas Injection

    NASA Astrophysics Data System (ADS)

    Tabarés, F. L.; Ferreira, J. A.; Ramos, A.; van Rooij, G.; Westerhout, J.; Al, R.; Rapp, J.; Drenik, A.; Mozetic, M.

    2010-10-01

    A technique based on reactive gas injection in the afterglow region of the divertor plasma is proposed for the suppression of tritium-carbon codeposits in remote areas of ITER when operated with carbon-based divertor targets. Experiments in a divertor simulator plasma device indicate that a 4nm/min deposition can be suppressed by addition of 1Pa·m3s-1 ammonia flow at 10 cm from the plasma. These results bolster the concept of nonperturbative scavenger injection for tritium inventory control in carbon-based fusion plasma devices, thus paving the way for ITER operation in the active phase under a carbon-dominated, plasma facing component background.

  4. Barefoot running: biomechanics and implications for running injuries.

    PubMed

    Altman, Allison R; Davis, Irene S

    2012-01-01

    Despite the technological developments in modern running footwear, up to 79% of runners today get injured in a given year. As we evolved barefoot, examining this mode of running is insightful. Barefoot running encourages a forefoot strike pattern that is associated with a reduction in impact loading and stride length. Studies have shown a reduction in injuries to shod forefoot strikers as compared with rearfoot strikers. In addition to a forefoot strike pattern, barefoot running also affords the runner increased sensory feedback from the foot-ground contact, as well as increased energy storage in the arch. Minimal footwear is being used to mimic barefoot running, but it is not clear whether it truly does. The purpose of this article is to review current and past research on shod and barefoot/minimal footwear running and their implications for running injuries. Clearly more research is needed, and areas for future study are suggested.

  5. Why Does My Nose Run?

    MedlinePlus

    ... to Know About Puberty Train Your Temper Why Does My Nose Run? KidsHealth > For Kids > Why Does My Nose Run? Print A A A en ... smell, you must be upside down! But why does your nose run? Read on to find out ...

  6. The Running Athlete

    PubMed Central

    Henning, P. Troy

    2014-01-01

    Context: Pelvic stress fractures, osteitis pubis, and snapping hip syndrome account for a portion of the overuse injuries that can occur in the running athlete. Evidence Acquisition: PubMed searches were performed for each entity using the following keywords: snapping hip syndrome, coxa sultans, pelvic stress fracture, and osteitis pubis from 2008 to 2013. Topic reviews, case reports, case series, and randomized trials were included for review. Study Design: Clinical review. Level of Evidence: Level 4. Results: Collectively, 188 articles were identified. Of these, 58 were included in this review. Conclusion: Based on the available evidence, the majority of these overuse injuries can be managed non-operatively. Primary treatment should include removal from offending activity, normalizing regional muscle strength/length imbalances and nutritional deficiencies, and mitigating training errors through proper education of the athlete and training staff. Strength of Recommendation Taxonomy: C PMID:24587861

  7. Pediatric running injuries.

    PubMed

    Seto, Craig K; Statuta, Siobhan M; Solari, Ian L

    2010-07-01

    As more children have become involved in athletic activities and running, there has been a significant increase in overuse injuries. The young athlete with open growth plates is vulnerable to unique overuse injuries involving the apophyses, articular cartilage, and growth plate. The physician caring for these young athletes needs to be aware of these conditions to diagnose and treat them appropriately. Physicians should also be aware of the risk of overtraining and overuse injury in athletes participating in year-round sports and competition. Current guidelines for overuse injury prevention in young athletes are primarily based on consensus and expert opinion. Further research is needed to provide evidence-based guidelines for overuse injury prevention in young athletes and runners. Copyright 2010 Elsevier Inc. All rights reserved.

  8. SAVAGE RUN WILDERNESS, WYOMING.

    USGS Publications Warehouse

    McCallum, M.E.; Kluender, Steven E.

    1984-01-01

    Mineral evaluation and related surveys were conducted in the Savage Run Wilderness in Wyoming and results of these studies indicate probable mineral-resource potential in four areas. Gold and (or) silver mineralization in veins associated with faults was found in two areas; all known occurrences inside the wilderness are very small in size. Slightly anomalous values of platinum, palladium, and nickel were recorded from rock-chip and stream- sediment samples from the southeast portion of the wilderness where layered mafic rocks predominate, and a probable resource potential exists for platinum, palladium, and nickel. An area of sheared rocks in the northeastern corner of the wilderness has a probable resource potential for copper. The nature of the geologic terrane precludes the occurrence of organic fuels.

  9. CFE-2 Experiment Run

    NASA Image and Video Library

    2013-11-11

    View of Flight Engineer (FE) Mike Hopkins initiating a CFE-2 (Capillary Flow Experiment - 2) Interior Corner Flow - 5 (ICF-5) test run. Liquids behave differently in space than they do on Earth, so containers that can process, hold or transport them must be designed carefully to work in microgravity. The Capillary Flow Experiment-2 furthers research on wetting, which is a liquid's ability to spread across a surface, and its impact over large length scales in strange container shapes in microgravity environments. This work will improve our capabilities to quickly and accurately predict how related processes occur, and allow us to design better systems to process liquids aboard spacecraft (i.e., liquid fuel tanks, thermals fluids, and water processing for life support). Image was released by astronaut on Twitter.

  10. CFE-2 Experiment Run

    NASA Image and Video Library

    2013-11-21

    View of Flight Engineer (FE) Koichi Wakata posing for a photo during a CFE-2 (Capillary Flow Experiment - 2) Interior Corner Flow - 8 (ICF-8) test run. Liquids behave differently in space than they do on Earth, so containers that can process, hold or transport them must be designed carefully to work in microgravity. The Capillary Flow Experiment-2 furthers research on wetting, which is a liquid's ability to spread across a surface, and its impact over large length scales in strange container shapes in microgravity environments. This work will improve capabilities to quickly and accurately predict how related processes occur, and allow us to design better systems to process liquids aboard spacecraft (i.e., liquid fuel tanks, thermals fluids, and water processing for life support). Image was released by astronaut on Twitter.

  11. Running WASP at Argonne

    SciTech Connect

    Huber, C.C.

    1981-01-01

    The WASP model was initially implemented at Argonne for the International Training course on Electric System Planning being conducted at Argonne. This implementation was done with special consideration to course participants who are unfamiliar with WASP and with the computer system they use during the course. Cataloged Procedures were developed for this purpose. The procedures simplify using WASP and enable participants to quickly start using WASP with a minimum of training. Within the procedures, features were added that enhance WASP. These features include a formatted printout of WASP input data and a historical log of all runs and inut data used. For the RENAME step, an alternate method is presented, with special comment concerning the WASP3 release.

  12. Strong Coupling Gauge Theories in LHC ERA

    NASA Astrophysics Data System (ADS)

    Fukaya, H.; Harada, M.; Tanabashi, M.; Yamawaki, K.

    2011-01-01

    AdS/QCD, light-front holography, and the nonperturbative running coupling / Stanley J. Brodsky, Guy de Teramond and Alexandre Deur -- New results on non-abelian vortices - Further insights into monopole, vortex and confinement / K. Konishi -- Study on exotic hadrons at B-factories / Toru Iijima -- Cold compressed baryonic matter with hidden local symmetry and holography / Mannque Rho -- Aspects of baryons in holographic QCD / T. Sakai -- Nuclear force from string theory / K. Hashimoto -- Integrating out holographic QCD back to hidden local symmetry / Masayasu Harada, Shinya Matsuzaki and Koichi Yamawaki -- Holographic heavy quarks and the giant Polyakov loop / Gianluca Grignani, Joanna Karczmarek and Gordon W. Semenoff -- Effect of vector-axial-vector mixing to dilepton spectrum in hot and/or dense matter / Masayasu Harada and Chihiro Sasaki -- Infrared behavior of ghost and gluon propagators compatible with color confinement in Yang-Mills theory with the Gribov horizon / Kei-Ichi Kondo -- Chiral symmetry breaking on the lattice / Hidenori Fukaya [for JLQCD and TWQCD collaborations] -- Gauge-Higgs unification: Stable Higgs bosons as cold dark matter / Yutaka Hosotani -- The limits of custodial symmetry / R. Sekhar Chivukula ... [et al.] -- Higgs searches at the tevatron / Kazuhiro Yamamoto [for the CDF and D[symbol] collaborations] -- The top triangle moose / R. S. Chivukula ... [et al.] -- Conformal phase transition in QCD like theories and beyond / V. A. Miransky -- Gauge-Higgs unification at LHC / Nobuhito Maru and Nobuchika Okada -- W[symbol]W[symbol] scattering in Higgsless models: Identifying better effective theories / Alexander S. Belyaev ... [et al.] -- Holographic estimate of Muon g - 2 / Deog Ki Hong -- Gauge-Higgs dark matter / T. Yamashita -- Topological and curvature effects in a multi-fermion interaction model / T. Inagaki and M. Hayashi -- A model of soft mass generation / J. Hosek -- TeV physics and conformality / Thomas Appelquist -- Conformal

  13. Running vacuum cosmological models: linear scalar perturbations

    NASA Astrophysics Data System (ADS)

    Perico, E. L. D.; Tamayo, D. A.

    2017-08-01

    In cosmology, phenomenologically motivated expressions for running vacuum are commonly parameterized as linear functions typically denoted by Λ(H2) or Λ(R). Such models assume an equation of state for the vacuum given by bar PΛ = - bar rhoΛ, relating its background pressure bar PΛ with its mean energy density bar rhoΛ ≡ Λ/8πG. This equation of state suggests that the vacuum dynamics is due to an interaction with the matter content of the universe. Most of the approaches studying the observational impact of these models only consider the interaction between the vacuum and the transient dominant matter component of the universe. We extend such models by assuming that the running vacuum is the sum of independent contributions, namely bar rhoΛ = Σibar rhoΛi. Each Λ i vacuum component is associated and interacting with one of the i matter components in both the background and perturbation levels. We derive the evolution equations for the linear scalar vacuum and matter perturbations in those two scenarios, and identify the running vacuum imprints on the cosmic microwave background anisotropies as well as on the matter power spectrum. In the Λ(H2) scenario the vacuum is coupled with every matter component, whereas the Λ(R) description only leads to a coupling between vacuum and non-relativistic matter, producing different effects on the matter power spectrum.

  14. Non-Perturbative Yang-Mills from Supersymmetry and Strings, Or, in the Jungles of Strong Coupling

    NASA Astrophysics Data System (ADS)

    Shifman, M.

    2005-12-01

    I summarize some recent developments in the issue of planar equivalence between supersymmetric Yang-Mills theory and its orbifold/orientifold daughters. This talk is based on works carried out in collaboration with Adi Armoni, Sasha Gorsky and Gabriele Veneziano.

  15. APEX: A Prime EXperiment at Jefferson Lab - Test Run Results and Full Run Plans; Update

    SciTech Connect

    Beacham, James

    2015-06-01

    APEX is an experiment at Thomas Jefferson National Accelerator Facility (JLab) in Virginia, USA, that searches for a new gauge boson (A') with sub-GeV mass and coupling to ordinary matter of g' ~ (10-6 - 10⁻²)e. Electrons impinge upon a fixed target of high-Z material. An A' is produced via a process analogous to photon bremsstrahlung, decaying to an e⁺+e⁻ pair. A test run was held in July of 2010, covering mA' = 175 to 250 MeV and couplings g'/e > 10⁻³. A full run is approved and will cover mA' ~ 65 to 525 MeV and g'/e > 2.3 x 10⁻⁴, and is expected to occur sometime in 2016 or 2017.

  16. APEX: A Prime EXperiment at Jefferson Lab. Test Run Results and Full Run Plans; Update

    NASA Astrophysics Data System (ADS)

    Beacham, James

    2015-06-01

    APEX is an experiment at Thomas Jefferson National Accelerator Facility (JLab) in Virginia, USA, that searches for a new gauge boson (A') with sub-GeV mass and coupling to ordinary matter of g' ˜ (10-6 - 10-2)e. Electrons impinge upon a fixed target of high-Z material. An A' is produced via a process analogous to photon bremsstrahlung, decaying to an e+e- pair. A test run was held in July of 2010, covering mA' = 175 to 250 MeV and couplings g'/e > 10-3. A full run is approved and will cover mA' ˜ 65 to 525 MeV and g'/e > 2.3 × 10-4, and is expected to occur sometime in 2016 or 2017.

  17. Voluntary Wheel Running in Mice

    PubMed Central

    Goh, Jorming; Ladiges, Warren

    2015-01-01

    Voluntary wheel running in the mouse is used to assess physical performance and endurance and to model exercise training as a way to enhance health. Wheel running is a voluntary activity in contrast to other experimental exercise models in mice, which rely on aversive stimuli to force active movement. The basic protocol consists of allowing mice to run freely on the open surface of a slanted plastic saucer-shaped wheel placed inside a standard mouse cage. Rotations are electronically transmitted to a USB hub so that frequency and rate of running can be captured to a software program for data storage and analysis for variable time periods. Mice are individually housed so that accurate recordings can be made for each animal. Factors such as mouse strain, gender, age, and individual motivation, which affect running activity, must be considered in the design of experiments using voluntary wheel running. PMID:26629772

  18. Nanosecond-pulse-controlled higher-order sideband comb in a GaAs optomechanical disk resonator in the non-perturbative regime

    SciTech Connect

    Xiong, Hao; Si, Liu-Gang; Lü, Xin-You; Yang, Xiaoxue; Wu, Ying

    2014-10-15

    We propose an interesting scheme for tunable high-order sideband comb generation by utilizing ultrastrong optomechanical interaction in a GaAs optomechanical disk resonator beyond the perturbative approximation. We analyze the nonlinear nature of the optomechanical interaction, and give a full description of the non-perturbative effects. It is shown, within the non-perturbative regime, that high-order sideband comb with large intensities can be realized and controlled in a GaAs optomechanical disk resonator with experimentally achievable system parameters, and the non-perturbative regime leads to rich and nontrivial behavior.

  19. Biodiversity conservation in running waters

    SciTech Connect

    Allan, J.D. ); Flecker, A.S. )

    1993-01-01

    In the concerns about biodiversity conservation, fresh waters have received less attention than tropical forests and oceans. However, running waters harbor a diverse panoply of species, habitats, and ecosystems, including some of the most threatened and many having great value to human society. An overview of the biological diversity of running waters and the state of imperilment is presented. Six major factors that threaten destruction of running water species and ecosystems are discussed: habitat loss and degradation; species invasions; overharvesting; secondary extinctions; chemical and organic pollution; global climate change. General measures for recovery and restoration of running waters conclude the article.

  20. A Running Start: Resource Guide for Youth Running Programs

    ERIC Educational Resources Information Center

    Jenny, Seth; Becker, Andrew; Armstrong, Tess

    2016-01-01

    The lack of physical activity is an epidemic problem among American youth today. In order to combat this, many schools are incorporating youth running programs as a part of their comprehensive school physical activity programs. These youth running programs are being implemented before or after school, at school during recess at the elementary…

  1. A Running Start: Resource Guide for Youth Running Programs

    ERIC Educational Resources Information Center

    Jenny, Seth; Becker, Andrew; Armstrong, Tess

    2016-01-01

    The lack of physical activity is an epidemic problem among American youth today. In order to combat this, many schools are incorporating youth running programs as a part of their comprehensive school physical activity programs. These youth running programs are being implemented before or after school, at school during recess at the elementary…

  2. Coupled-rearrangement-channel Gaussian-basis variational method for trinucleon bound states

    NASA Astrophysics Data System (ADS)

    Kameyama, H.; Kamimura, M.; Fukushima, Y.

    1989-08-01

    To the 3H and 3He ground states, we apply the coupled-rearrangement-channel variational method with Gaussian-basis functions which has successfully been used in precise calculations of muonic molecular ions, Coulomb-interacting three-body systems. The trinucleon wave function is decomposed into angular-momentum-projected three-body channels as done in the Faddeev equations method, but the interaction is fully incorporated with no partial-wave decomposition. The radial part of the channel amplitudes is expanded with a sufficient number of Gaussian-tail basis functions of the Jacobi coordinates. The Gaussian ranges are taken to be geometrical progressions which run from very short ranges through large enough ones. This ab initio variational approach is found to describe accurately both the short-range correlations and the asymptotic behavior. The Argonne V14 potential is used as an example of realistic two-nucleon interactions; for 3He, the Coulomb potential is included nonperturbatively. The calculation reproduces precisely the results of the Faddeev calculations for 3H and 3He for binding energy, probabilities of the S, S', P, and D states, and the S- and D-wave asymptotic normalization constants. Convergence of the present results is seen at a much smaller number of the three-body channels than in the Faddeev calculations. This is because the interaction is truncated in the angular momentum space in the Faddeev calculations but the full interaction is taken in the present method.

  3. The N/D method with non-perturbative left-hand-cut discontinuity and the S10NN partial wave

    NASA Astrophysics Data System (ADS)

    Entem, D. R.; Oller, J. A.

    2017-10-01

    In this letter we introduce an integral equation that allows to calculate the exact left-hand-cut discontinuity for an uncoupled S-wave partial-wave amplitude in potential scattering for a given finite-range potential. In particular this is applied here to the S10 nucleon-nucleon (NN) partial wave. The calculation of Δ (A) is completely fixed by the potential because short-range physics (corresponding to integrated out degrees of freedom within the low-energy Effective Field Theory) does not contribute to Δ (A). The results obtained from the N / D method for a partial-wave amplitude are rigorous, since now the discontinuities along the left-hand cut and right-hand cut are exactly known. This solves in this case the open question with respect to the N / D method and the effect on the final result of the non-perturbative iterative diagrams in the evaluation of Δ (A). The solution of this problem also implies the equivalence of the N / D method and the Lippmann-Schwinger (LS) equation for the nonsingular one-pion exchange S10NN potential (Yukawa potential). The equivalence between the N / D method with one extra subtraction and the LS equation renormalized with one counterterm or with subtractive renormalization also holds for the singular attractive S10NN potentials calculated by including higher orders in Chiral Perturbation Theory (ChPT). However, the N / D method is more flexible and, rather straightforwardly, it allows to evaluate partial-wave amplitudes with a higher number of extra subtractions, that we fix in terms of shape parameters within the effective range expansion. We give results up to three extra subtractions in the N / D method, which provide a rather accurate reproduction of the S10NN phase shifts when the NNLO ChPT potential is employed. Our new method then provides a general theory to renormalize non-perturbatively singular and regular potentials in scattering that can be extended to higher partial waves as well as to coupled channel scattering.

  4. Bethe/Gauge correspondence in odd dimension: modular double, non-perturbative corrections and open topological strings

    NASA Astrophysics Data System (ADS)

    Sciarappa, Antonio

    2016-10-01

    Bethe/Gauge correspondence as it is usually stated is ill-defined in five dimensions and needs a "non-perturbative" completion; a related problem also appears in three dimensions. It has been suggested that this problem, probably due to incompleteness of Omega background regularization in odd dimension, may be solved if we consider gauge theory on compact S 5 and S 3 geometries. We will develop this idea further by giving a full Bethe/Gauge correspondence dictionary on S 5 and S 3 focussing mainly on the eigenfunctions of (open and closed) relativistic 2-particle Toda chain and its quantized spectral curve: these are most properly written in terms of non-perturbatively completed NS open topological strings. A key ingredient is Faddeev's modular double structure which is naturally implemented by the S 5 and S 3 geometries.

  5. Perturbativity vs nonperturbativity in QED-effects for H-like atoms with Zα > 1

    NASA Astrophysics Data System (ADS)

    Roenko, A.; Sveshnikov, K.

    2017-08-01

    The behavior of levels near the threshold of the lower continuum in superheavy H-like atoms with Zα > 1, caused by the interaction ΔUAMM of the electron’s magnetic anomaly (AMM) dynamically screened at small distances ≪ 1/m, with the Coulomb field of atomic nucleus is considered by taking into account the complete dependence of electron’s wave function (WF) on Zα. It is shown that the calculation of the contribution caused by ΔUAMM via both the quark structure and the whole nucleus, considered as a uniformly charged extended Coulomb source, leads to results, which coincide within the accepted precision of calculations. It is also shown that there appears some difference in results between perturbative and nonperturbative methods of accounting for the contribution from ΔUAMM within the corresponding Dirac equation (DE) in favor of the latter. Moreover, the growth rate of the contribution from ΔUAMM reaches its maximum at Z ˜ 140-150, while by further increase of Z into the supercritical region Z ≫ Zcr,1, the shift of levels caused by ΔUAMM near the lower continuum decreases monotonically to zero. The last result is generalized to the whole self-energy contribution to the shift of levels and so to the possible behavior of radiative QED-effects with virtual photon exchange near the lower continuum.

  6. Nonperturbative effects of the minimal length uncertainty on the relativistic quantum mechanics

    NASA Astrophysics Data System (ADS)

    Pedram, Pouria

    2012-04-01

    We study the nonperturbative effects of the minimal length on the energy spectrum of a relativistic particle in the context of the generalized uncertainty principle (GUP). This form of GUP is consistent with various candidates of quantum gravity such as string theory, loop quantum gravity, and black-hole physics and predicts a minimum measurable length proportional to the Planck length. Using a recently proposed formally self-adjoint representation, we solve the generalized Dirac and Klein-Gordon equations in various situations and find the corresponding exact energy eigenvalues and eigenfunctions. We show that for the Dirac particle in a box, the number of the solutions renders to be finite as a manifestation of both the minimal length and the theory of relativity. For the case of the Dirac oscillator and the wave equations with scalar and vector linear potentials, we indicate that the solutions can be obtained in a more simpler manner through the self-adjoint representation. It is also shown that, in the ultrahigh frequency regime, the partition function and the thermodynamical variables of the Dirac oscillator can be expressed in a closed analytical form. The Lorentz violating nature of the GUP-corrected relativistic wave equations is discussed finally.

  7. Non-perturbative magnetic phenomena in closed-shell paramagnetic molecules.

    PubMed

    Tellgren, Erik I; Helgaker, Trygve; Soncini, Alessandro

    2009-07-14

    By means of non-perturbative ab initio calculations, it is shown that paramagnetic closed-shell molecules are characterized by a strongly non-linear magnetic response, whose main feature consists of a paramagnetic-to-diamagnetic transition in a strong magnetic field. The physical origin of this phenomenon is rationalised on the basis of an analytical model based on molecular orbital theory. For the largest molecules considered here, the acepleiadylene dianion and the corannulene dianion, the transition field is of the order of 10(3) T, about one order of magnitude larger than the magnetic field strength currently achievable in experimental settings. However, our simple model suggests that the paramagnetic-to-diamagnetic transition is a universal property of paramagnetic closed-shell systems in strong magnetic fields, provided no singlet-triplet level crossing occurs for fields smaller than the critical transition field. Accordingly, fields weaker than 100 T should suffice to trigger the predicted transition for systems whose size is still well within the (medium-large) molecular domain, such as hypothetical antiaromatic rings with less than one hundred carbon atoms.

  8. Exact quantization conditions, toric Calabi-Yau and non-perturbative topological string

    NASA Astrophysics Data System (ADS)

    Sun, Kaiwen; Wang, Xin; Huang, Min-xin

    2017-01-01

    We establish the precise relation between the Nekrasov-Shatashvili (NS) quantization scheme and Grassi-Hatsuda-Mariño conjecture for the mirror curve of arbitrary toric Calabi-Yau threefold. For a mirror curve of genus g, the NS quantization scheme leads to g quantization conditions for the corresponding integrable system. The exact NS quantization conditions enjoy a self S-duality with respect to Planck constant h and can be derived from the Lockhart-Vafa partition function of non-perturbative topological string. Based on a recent observation on the correspondence between spectral theory and topological string, another quantization scheme was proposed by Grassi-Hatsuda-Mariño, in which there is a single quantization condition and the spectra are encoded in the vanishing of a quantum Riemann theta function. We demonstrate that there actually exist at least g nonequivalent quantum Riemann theta functions and the intersections of their theta divisors coincide with the spectra determined by the exact NS quantization conditions. This highly nontrivial coincidence between the two quantization schemes requires infinite constraints among the refined Gopakumar-Vafa invariants. The equivalence for mirror curves of genus one has been verified for some local del Pezzo surfaces. In this paper, we generalize the correspondence to higher genus, and analyze in detail the resolved C^3/Z_5 orbifold and several SU( N ) geometries. We also give a proof for some models at ħ = 2π /k.

  9. Non-perturbative calculation of molecular magnetic properties within current-density functional theory.

    PubMed

    Tellgren, E I; Teale, A M; Furness, J W; Lange, K K; Ekström, U; Helgaker, T

    2014-01-21

    We present a novel implementation of Kohn-Sham density-functional theory utilizing London atomic orbitals as basis functions. External magnetic fields are treated non-perturbatively, which enable the study of both magnetic response properties and the effects of strong fields, using either standard density functionals or current-density functionals-the implementation is the first fully self-consistent implementation of the latter for molecules. Pilot applications are presented for the finite-field calculation of molecular magnetizabilities, hypermagnetizabilities, and nuclear magnetic resonance shielding constants, focusing on the impact of current-density functionals on the accuracy of the results. Existing current-density functionals based on the gauge-invariant vorticity are tested and found to be sensitive to numerical details of their implementation. Furthermore, when appropriately regularized, the resulting magnetic properties show no improvement over standard density-functional results. An advantage of the present implementation is the ability to apply density-functional theory to molecules in very strong magnetic fields, where the perturbative approach breaks down. Comparison with high accuracy full-configuration-interaction results show that the inadequacies of current-density approximations are exacerbated with increasing magnetic field strength. Standard density-functionals remain well behaved but fail to deliver high accuracy. The need for improved current-dependent density-functionals, and how they may be tested using the presented implementation, is discussed in light of our findings.

  10. Non-perturbative treatment of molecules in linear magnetic fields: calculation of anapole susceptibilities.

    PubMed

    Tellgren, Erik I; Fliegl, Heike

    2013-10-28

    In the present study a non-perturbative approach to ab initio calculations of molecules in strong, linearly varying, magnetic fields is developed. The use of London atomic orbitals (LAOs) for non-uniform magnetic fields is discussed and the standard rationale of gauge-origin invariance is generalized to invariance under arbitrary constant shifts of the magnetic vector potential. Our approach is applied to study magnetically induced anapole moments (or toroidal moments) and the related anapole susceptibilities for a test set of chiral and nonchiral molecules. For the first time numerical anapole moments are accessible on an ab initio level of theory. Our results show that the use of London atomic orbitals dramatically improves the basis set convergence also for magnetic properties related to non-uniform magnetic fields, at the cost that the Hellmann-Feynman theorem does not apply for a finite LAO basis set. It is shown that the mixed anapole susceptibility can be related to chirality, since its trace vanishes for an achiral molecule.

  11. Truthing the stretch: non-perturbative cosmological realizations with multiscale spherical collapse

    NASA Astrophysics Data System (ADS)

    Neyrinck, Mark C.

    2016-01-01

    Here we present a simple, parameter-free, non-perturbative algorithm that gives low-redshift cosmological particle realizations accurate to few-Megaparsec scales, called MUSCLE (MUltiscale Spherical-ColLapse Evolution). It has virtually the same cost as producing N-body-simulation initial conditions, since it works with the `stretch' parameter ψ, the Lagrangian divergence of the displacement field. It promises to be useful in quickly producing mock catalogues, and to simplify computationally intensive reconstructions of galaxy surveys. MUSCLE applies a spherical-collapse prescription on multiple Gaussian-smoothed scales. It achieves higher accuracy than perturbative schemes (Zel'dovich and second-order Lagrangian perturbation theory - 2LPT), and, by including the void-in-cloud process (voids in large-scale collapsing regions), solves problems with a single-scale spherical-collapse scheme. Slight further improvement is possible by mixing in the 2LPT estimate on large scales. Additionally, we show the behaviour of ψ for different morphologies (voids, walls, filaments, and haloes). A PYTHON code to produce these realizations is available at http://skysrv.pha.jhu.edu/˜neyrinck/muscle.html.

  12. Non-perturbative measurement of low-intensity charged particle beams

    NASA Astrophysics Data System (ADS)

    Fernandes, M.; Geithner, R.; Golm, J.; Neubert, R.; Schwickert, M.; Stöhlker, T.; Tan, J.; Welsch, C. P.

    2017-01-01

    Non-perturbative measurements of low-intensity charged particle beams are particularly challenging to beam diagnostics due to the low amplitude of the induced electromagnetic fields. In the low-energy antiproton decelerator (AD) and the future extra low energy antiproton rings at CERN, an absolute measurement of the beam intensity is essential to monitor the operation efficiency. Superconducting quantum interference device (SQUID) based cryogenic current comparators (CCC) have been used for measuring slow charged beams in the nA range, showing a very good current resolution. But these were unable to measure fast bunched beams, due to the slew-rate limitation of SQUID devices and presented a strong susceptibility to external perturbations. Here, we present a CCC system developed for the AD machine, which was optimised in terms of its current resolution, system stability, ability to cope with short bunched beams, and immunity to mechanical vibrations. This paper presents the monitor design and the first results from measurements with a low energy antiproton beam obtained in the AD in 2015. These are the first CCC beam current measurements ever performed in a synchrotron machine with both coasting and short bunched beams. It is shown that the system is able to stably measure the AD beam throughout the entire cycle, with a current resolution of 30 {nA}.

  13. Metal nanospheres under intense continuous-wave illumination: A unique case of nonperturbative nonlinear nanophotonics

    NASA Astrophysics Data System (ADS)

    Gurwich, I.; Sivan, Y.

    2017-07-01

    We show that the standard perturbative (i.e., cubic) description of the thermal nonlinear response of a single metal nanosphere to intense continuous-wave (CW) illumination is sufficient only for a temperature rise of up to 100 degrees above room temperature. Beyond this regime, the slowing down of the temperature rise requires a nonperturbative description of the nonlinear response, even though the permittivity is linearly dependent on the temperature and despite the deep subwavelength effective propagation distances involved. Using experimental data, we show that, generically, the increase of the imaginary part of the metal permittivity dominates the increase of the host permittivity as well as the resonance shift due to the joint changes to the real parts of the metal and host. Thus, the main nonlinear effect is a decrease of the quality factor of the resonance. We further analyze the relative importance of the various contributions to the temperature rise and thermal nonlinearity, compare the nonlinearity of Au and Ag, demonstrate the potential effect of the nanoparticle morphology, and show that although the thermo-optical nonlinearity of the host typically plays a minor role, its thermal conductivity and its temperature dependence is important. Finally, we discuss the differences between CW and ultrafast thermal nonlinearities.

  14. Nonperturbative quantum and classical calculations of multiphoton vibrational excitation and dissociation of Morse molecules^1

    NASA Astrophysics Data System (ADS)

    Dimitriou, K. I.; Mercouris, Th.; Constantoudis, V.; Komninos, Y.; Nicolaides, C. A.

    2006-05-01

    The multiphoton vibrational excitation and dissociation of Morse molecules have been computed nonperturbatively using Hamilton's and Schrφdinger's time-dependent equations, for a range of laser pulse parameters. The time-dependent Schrφdinger equation is solved by the state-specific expansion approach [e.g.,1]. For its solution, emphasis has been given on the inclusion of the continuous spectrum, whose contribution to the multiphoton probabilities for resonance excitation to a number of excited discrete states as well as to dissociation has been examined as a function of laser intensity, frequency and pulse duration. An analysis of possible quantal-classical correspondences for this system is being carried out. We note that distinct features exist from previous classical calculations [2]. For example, the dependence on the laser frequency gives rise to an asymmetry around the red-shifted frequency corresponding to the maximum probability. [1] Th. Mercouris, I. D. Petsalakis and C. A. Nicolaides, J. Phys. B 27, L519 (1994). [2] V. Constantoudis and C. A. Nicolaides, Phys. Rev. E 64, 562112 (2001). ^1This work was supported by the program 'Pythagoras' which is co - funded by the European Social Fund (75%) and Natl. Resources (25%). ^2Physics Department, National Technical University, Athens, Greece.^3Theoretical and Physical Chemistry Institute, Hellenic Research Foundation, Athens, Greece.

  15. Internal, nonperturbing, radio frequency wave monitor reflectometer system on the DIII-D tokamaka)

    NASA Astrophysics Data System (ADS)

    Lee, J. H.; Doyle, E. J.; Luhmann, N. C., Jr.; Peebles, W. A.; Petty, C. C.; Pinsker, R. I.; Rettig, C. L.; Rhodes, T. L.

    1995-02-01

    A new reflectometer system designed to monitor density fluctuations associated with rf waves has been successfully demonstrated on the DIII-D tokamak. It is a direct, internal, and nonperturbing diagnostic with access into the plasma core. This new diagnostic is motivated by a desire to improve understanding of rf wave physics issues, such as wave trajectory, heating mechanisms, rf wave deposition profile, and wave number, and is highly relevant to planned tokamaks such as ITER and TPX. This work is the first application of reflectometry to rf wave studies in a tokamak. Feedforward tracking receiver techniques are employed to remove frequency instabilities due to inherent drifts in the microwave sources and frequency pulling. In order to minimize spurious pickup of the rf pulse (˜60 MHz), heterodyne detection techniques are utilized, and all components are installed inside an rf shielding box. The system operates in the extraordinary mode (X-mode) at 70 GHz. In this paper, a detailed description of the system, and data illustrating its successful operation will be presented.

  16. A simple non-perturbing cell migration assay insensitive to proliferation effects.

    PubMed

    Glenn, Honor L; Messner, Jacob; Meldrum, Deirdre R

    2016-08-18

    Migration is a fundamental cellular behavior that plays an indispensable role in development and homeostasis, but can also contribute to pathology such as cancer metastasis. Due to its relevance to many aspects of human health, the ability to accurately measure cell migration is of broad interest, and numerous approaches have been developed. One of the most commonly employed approaches, because of its simplicity and throughput, is the exclusion zone assay in which cells are allowed to migrate into an initially cell-free region. A major drawback of this assay is that it relies on simply counting cells in the exclusion zone and therefore cannot distinguish the effects of proliferation from migration. We report here a simple modification to the exclusion zone migration assay that exclusively measures cell migration and is not affected by proliferation. This approach makes use of a lineage-tracing vital stain that is retained through cell generations and effectively reads out migration relative to the original, parental cell population. This modification is simple, robust, non-perturbing, and inexpensive. We validate the method in a panel of cell lines under conditions that inhibit or promote migration and demonstrate its use in normal and cancer cell lines as well as primary cells.

  17. A note on the nonperturbative nature of the Schwinger effect in the expanding de Sitter space

    NASA Astrophysics Data System (ADS)

    Nicolaevici, Nistor

    2015-03-01

    We reconsider a recent perturbative calculation [M. A. Băloi, Mod. Phys. Lett. A29, 1450138 (2014)] of particle production in the expanding de Sitter space in an external electromagnetic field and apply it to the case of a constant uniform electric field in two dimensions. We show that perturbative number of created particles significantly differs from the existing nonperturbative result based on the Bogoliubov transformation method. We also point out that for a physically meaningful perturbative amplitude one should restrict to external potentials Aμ which in conformal coordinates vanish at infinite times. Potentials which do not respect this condition lead to gauge-dependent amplitudes, which also show close similarities with amplitudes in flat space in the unphysical case when the external potential suddenly vanishes. These problems are intimately linked with the finite upper limit of the conformal time in the de Sitter space and most probably a similar restriction should be imposed in perturbative calculations in FRW spacetimes with the same property.

  18. Nonperturbative effects and indirect exchange interaction between quantum impurities on metallic (111) surfaces

    NASA Astrophysics Data System (ADS)

    Allerdt, A.; Žitko, R.; Feiguin, A. E.

    2017-06-01

    The (111) surface of noble metals is usually treated as an isolated two-dimensional (2D) triangular lattice completely decoupled from the bulk. However, unlike in topological insulators, bulk bands also cross the Fermi level. We here introduce an effective tight-binding model that accurately reproduces results from first-principles calculations, accounting for both surface and bulk states. We numerically solve the many-body problem of two quantum impurities sitting on the surface by means of the density matrix renormalization group. By performing simulations in a star geometry, we are able to study the nonperturbative problem in the thermodynamic limit with machine precision accuracy. We find that there is a nontrivial competition between Kondo and RKKY physics and as a consequence, ferromagnetism is never developed, except at short distances. The bulk introduces a variation in the period of the RKKY interactions, and therefore the problem departs considerably from the simpler 2D case. In addition, screening and the magnitude of the effective indirect exchange are enhanced by the contributions from the bulk states.

  19. Coordinating the 2009 RHIC Run

    ScienceCinema

    Brookhaven Lab - Mei Bai

    2016-07-12

    Physicists working at the Brookhaven National Lab's Relativistic Heavy Ion Collider (RHIC) are exploring the puzzle of proton spin as they begin taking data during the 2009 RHIC run. For the first time, RHIC is running at a record energy of 500 giga-elect

  20. Coordinating the 2009 RHIC Run

    SciTech Connect

    Brookhaven Lab - Mei Bai

    2009-04-13

    Physicists working at the Brookhaven National Lab's Relativistic Heavy Ion Collider (RHIC) are exploring the puzzle of proton spin as they begin taking data during the 2009 RHIC run. For the first time, RHIC is running at a record energy of 500 giga-elect

  1. Renormalization of local quark-bilinear operators for Nf=3 flavors of stout link nonperturbative clover fermions

    NASA Astrophysics Data System (ADS)

    Constantinou, M.; Horsley, R.; Panagopoulos, H.; Perlt, H.; Rakow, P. E. L.; Schierholz, G.; Schiller, A.; Zanotti, J. M.

    2015-01-01

    The renormalization factors of local quark-bilinear operators are computed nonperturbatively for Nf=3 flavors of stout link nonperturbative clover (SLiNC) fermions, with emphasis on the various procedures for the chiral and continuum extrapolations. The simulations are performed at a lattice spacing a =0.074 fm , and for five values of the pion mass in the range of 290-465 MeV, allowing a safe and stable chiral extrapolation. Emphasis is given in the subtraction of the well-known pion pole which affects the renormalization factor of the pseudoscalar current. We also compute the inverse propagator and the Green's functions of the local bilinears to one loop in perturbation theory. We investigate lattice artifacts by computing them perturbatively to second order as well as to all orders in the lattice spacing. The renormalization conditions are defined in the RI'-MOM scheme, for both the perturbative and nonperturbative results. The renormalization factors, obtained at different values of the renormalization scale, are translated to the MS ¯ scheme and are evolved perturbatively to 2 GeV. Any residual dependence on the initial renormalization scale is eliminated by an extrapolation to the continuum limit. We also study the various sources of systematic errors. Particular care is taken in correcting the nonperturbative estimates by subtracting lattice artifacts computed to one-loop perturbation theory using the same action. We test two different methods, by subtracting either the O (g2a2) contributions, or the complete (all orders in a ) one-loop lattice artifacts.

  2. Nonperturbative effects of vacuum polarization for a quasi-one-dimensional Dirac-Coulomb system with Z > Z cr

    NASA Astrophysics Data System (ADS)

    Voronina, Yu.; Davydov, A.; Sveshnikov, K.

    2017-09-01

    Major nonperturbative properties of the vacuum charge density ρ VP ( x) and vacuum-polarization energy ξ VP are considered for an overcritical Coulomb source with Z > Z cr in 1 + 1 D. We demonstrate that, for a broad range of external-field parameters, vacuum energy may significantly deviate from the perturbative quadratic increase and even decrease towards deeply negative values due to vacuum polarization in the overcritical region.

  3. Oxygen cost of running barefoot vs. running shod.

    PubMed

    Hanson, N J; Berg, K; Deka, P; Meendering, J R; Ryan, C

    2011-06-01

    The purpose of this study was to investigate the oxygen cost of running barefoot vs. running shod on the treadmill as well as overground. 10 healthy recreational runners, 5 male and 5 female, whose mean age was 23.8±3.39 volunteered to participate in the study. Subjects participated in 4 experimental conditions: 1) barefoot on treadmill, 2) shod on treadmill, 3) barefoot overground, and 4) shod overground. For each condition, subjects ran for 6 min at 70% vVO (2)max pace while VO (2), heart rate (HR), and rating of perceived exertion (RPE) were assessed. A 2 × 2 (shoe condition x surface) repeated measures ANOVA revealed that running with shoes showed significantly higher VO (2) values on both the treadmill and the overground track (p<0.05). HR and RPE were significantly higher in the shod condition as well (p<0.02 and p<0.01, respectively). For the overground and treadmill conditions, recorded VO (2) while running shod was 5.7% and 2.0% higher than running barefoot. It was concluded that at 70% of vVO (2)max pace, barefoot running is more economical than running shod, both overground and on a treadmill.

  4. Spectral classification of coupling regimes in the quantum Rabi model

    NASA Astrophysics Data System (ADS)

    Rossatto, Daniel Z.; Villas-Bôas, Celso J.; Sanz, Mikel; Solano, Enrique

    2017-07-01

    The quantum Rabi model is in the scientific spotlight due to the recent theoretical and experimental progress. Nevertheless, a full-fledged classification of its coupling regimes remains as a relevant open question. We propose a spectral classification dividing the coupling regimes into three regions based on the validity of perturbative criteria on the quantum Rabi model, which allows us the use of exactly solvable effective Hamiltonians. These coupling regimes are (i) the perturbative ultrastrong coupling regime which comprises the Jaynes-Cummings model, (ii) a region where nonperturbative ultrastrong and nonperturbative deep strong coupling regimes coexist, and (iii) the perturbative deep strong coupling regime. We show that this spectral classification depends not only on the ratio between the coupling strength and the natural frequencies of the unperturbed parts, but also on the energy to which the system can access. These regimes additionally discriminate the completely different behaviors of several static physical properties, namely the total number of excitations, the photon statistics of the field, and the cavity-qubit entanglement. Finally, we explain the dynamical properties which are traditionally associated with the deep strong coupling regime, such as the collapses and revivals of the state population, in the frame of the proposed spectral classification.

  5. Eikonal Scattering at Strong Coupling

    NASA Astrophysics Data System (ADS)

    Irizarry-Gelpi, Melvin Eloy

    The scattering of subatomic particles is a source of important physical phenomena. Decades of work have yielded many techniques for the computation of scattering amplitudes. Most of these techniques involve perturbative quantum field theory and thus apply only at weak coupling. Complementary to scattering is the formation of bound states, which are intrinsically nonperturbative. Regge theory arose in the late 1950s as an attempt to describe, with a single framework, both scattering and the formation of bound states. In Regge theory one obtains an amplitude with bound state poles after analytic continuation of a nonperturbative scattering amplitude, corresponding to a sum of an infinite number of Feynman diagrams at large energy and fixed momentum transfer (but with crossed kinematics). Thus, in order to obtain bound states at fixed energy, one computes an amplitude at large momentum transfer. In this dissertation we calculate amplitudes with bound states in the regime of fixed energy and small momentum transfer. We formulate the elastic scattering problem in terms of many-body path integrals, familiar from quantum mechanics. Then we invoke the semiclassical JWKB approximation, where the path integral is dominated by classical paths. The dynamics in the semiclassical regime are strongly coupled, as found by Halpern and Siegel. When the momentum transfer is small, the classical paths are simple straight lines and the resulting semiclassical amplitudes display a spectrum of bound states that agrees with the spectrum found by solving wave equations with potentials. In this work we study the bound states of matter particles with various types of interactions, including electromagnetic and gravitational interactions. Our work has many analogies with the work started by Alday and Maldacena, who computed scattering amplitudes of gluons at strong coupling with semiclassical quantum mechanics of strings in anti de-Sitter spacetime. We hope that in the future we can apply our

  6. Stochastic averaging of the time-evolution operator for quantum systems driven by Ornstein-Uhlenbeck colored noise: A nonperturbative cluster cumulant method

    NASA Astrophysics Data System (ADS)

    Guha, S.; Sanyal, G.; Mandal, S. H.; Mukherjee, D.

    1993-04-01

    We have developed in this paper a nonperturbative cluster-expansion strategy for generating the stochastically averaged time-evolution operator for quantum systems driven by Ornstein-Uhlenbeck (OU) colored noise. The method induces a boson mapping of the (real or complex) stochastic variable f, and interprets the stochastic average of a pair of variables f at two different times as the expectation value of the time-ordered product of the associated bosons with respect to the boson vacuum ||0B>. The stochastic evolution is thus mapped onto a deterministic evolution in an expanded Fock space. The evolution of the system from the groups of state of interest is monitored using our recently developed nonperturbative time-dependent multireference coupled-cluster (TDMRCC) method. In this, the evolution operator U is written in a factorized form UexUM, where UM evolves in the space of the starting functions (model space) and Uex brings in the virtual functions. Uex and UM are both written as normal ordered exponentials involving cluster operators. In the present context, the TDMRCC method translates into one for generating the evolution operator UB for the Hamiltonian containing the additional boson variables, and the stochastic averaging of UB is realized as the expectation value <0B||UB||0B>. We call the TDMRCC method involving the expanded Fock space a cluster cumulant method. We have analyzed the relation of the cluster cumulant approach with the Fox-Kubo operator cumulant expansion and the method of marginal averages involving the Fokker-Planck operator of the OU process. It has been shown that an order by order expansion of our equations in the power of stochastic coupling generates the perturbative cumulant results of Fox and Kubo. It is also demonstrated that the traditional Fokker-Planck method of marginal averages uses a Kubo-Schrödinger operator which is related to our boson mapped Hamiltonian by a transformation which converts the Fokker-Planck operator Γ to

  7. The Run-Up of Subduction Zones

    NASA Astrophysics Data System (ADS)

    Riquelme, S.; Bravo, F. J.; Fuentes, M.; Matias, M.; Medina, M.

    2016-12-01

    Large earthquakes in subduction zones are liable to produce tsunamis that can cause destruction and fatalities. The Run-up is a geophysical parameter that quantifies damage and if critical facilities or population are exposed to. Here we use the coupling for certain subduction regions measured by different techniques (Potency and GPS observations) to define areas where large earthquakes can occur. Taking the slab 1.0 from the United States Geological Survey (USGS), we can define the geometry of the area including its tsunamigenic potential. By using stochastic earthquakes sources for each area with its maximum tsunamigenic potential, we calculate the numerical and analytical run-up for each case. Then, we perform a statistical analysis and calculate the envelope for both methods. Furthermore, we build an index of risk using: the closest slope to the shore in a piecewise linear approach (last slopecriteria) and the outputsfrom tsunami modeling. Results show that there are areas prone to produce higher run-up than others based on the size of the earthquake, geometrical constraints of the source, tectonic setting and the coast last slope. Based on these results, there are zones that have low risk index which can define escape routes or secure coastal areas for tsunami early warning, urban and planning purposes when detailed data is available.

  8. Wheel running in the wild.

    PubMed

    Meijer, Johanna H; Robbers, Yuri

    2014-07-07

    The importance of exercise for health and neurogenesis is becoming increasingly clear. Wheel running is often used in the laboratory for triggering enhanced activity levels, despite the common objection that this behaviour is an artefact of captivity and merely signifies neurosis or stereotypy. If wheel running is indeed caused by captive housing, wild mice are not expected to use a running wheel in nature. This however, to our knowledge, has never been tested. Here, we show that when running wheels are placed in nature, they are frequently used by wild mice, also when no extrinsic reward is provided. Bout lengths of running wheel behaviour in the wild match those for captive mice. This finding falsifies one criterion for stereotypic behaviour, and suggests that running wheel activity is an elective behaviour. In a time when lifestyle in general and lack of exercise in particular are a major cause of disease in the modern world, research into physical activity is of utmost importance. Our findings may help alleviate the main concern regarding the use of running wheels in research on exercise.

  9. Effects of marathon running on running economy and kinematics.

    PubMed

    Kyröläinen, H; Pullinen, T; Candau, R; Avela, J; Huttunen, P; Komi, P V

    2000-07-01

    The present study was designed to investigate interactions between running economy and mechanics before, during, and after an individually run marathon. Seven experienced triathletes performed a 5-min submaximal running test on a treadmill at an individual constant marathon speed. Heart rate was monitored and the expired respiratory gas was analyzed. Blood samples were drawn to analyze serum creatine kinase activity (S-CK), skeletal troponin I (sTnI), and blood lactate (B-La). A video analysis was performed (200 frames x s(-1)) to investigate running mechanics. A kinematic arm was used to determine the external work of each subject. The results of the present study demonstrate that after the marathon, a standardized 5-min submaximal running test resulted in an increase in oxygen consumption, ventilation, and heart rate (P < 0.05), with a simultaneous decrease in the oxygen difference (%) between inspired and expired air, and respiratory exchange ratio (P < 0.05). B-La did not change during the marathon, while sTnI and S-CK values increased (P < 0.05), peaking 2 h and 2 days after the marathon, respectively. With regard to the running kinematics, a minor increase in stride frequency and a similar decrease in stride length were observed (P < 0.01). These results demonstrate clearly that weakened running economy cannot be explained by changes in running mechanics. Therefore, it is suggested that the increased physiological loading is due to several mechanisms: increased utilization of fat as an energy substrate, increased demands of body temperature regulation, and possible muscle damage.

  10. Run-to-Run Control Strategy for Diabetes Management

    DTIC Science & Technology

    2007-11-02

    quite serious ( diabetic coma), and the long- term implications of varying glucose levels ( nephropathy , retinopathy, and other tissue damage ) have...Trial Re- search Group, \\The e ect of intensive treatment of diabetes on the development and progression of long{term complications in insulin{dependent...1 RUN-TO-RUN CONTROL STRATEGY FOR DIABETES MANAGEMENT F.J. Doyle III1, B. Srinivasan2, and D. Bonvin2 1Department of Chemical Engineering, University

  11. APS runControl library

    SciTech Connect

    Saunders, C.; Borland, M.

    1995-10-25

    This document serves as a User`s Manual and Reference for the runControl library. This library is designed to be used by closed- loop EPICS control applications which are generally run in the background on the controls workstations. It permits an application to `register` itself with an EPICS record, thereby preventing additional instances of the same application from being run. In addition, the executing application may in turn be suspended or aborted via an MEDM control screen or other standard channel access client.

  12. Dirichlet branes and nonperturbative aspects of supersymmetric string and gauge theories

    SciTech Connect

    Yin, Zheng

    1998-05-01

    In chapter 1 the author reviews some elements of string theory relevant to the rest of this report. He touches on both the classical, i.e. perturbative, string physics before D-branes rise to prominence, and some of the progresses they brought forth. In chapter 2 he proceeds to give an exact algebraic formulation of D-branes in curved spaces. This allows one to classify them in backgrounds of interest and study their geometric properties. He applies this formalism to string theory on Calabi-Yau and other supersymmetry preserving manifolds. Then he studies the behavior of the D-branes under mirror symmetry in chapter 3. Mirror symmetry is known to be a symmetry of string theory perturbatively. He finds evidence for its nonperturbative validity when D-branes are also considered and compute some dynamical consequences. In chapter 4 he turns to examine the consistency of curved and/or intersecting D-brane configurations. They have been used recently to extract information about the field theories that arise in certain limits. It turns out that there are potential quantum mechanical inconsistencies associated with them. What saves the day are certain subtle topological properties of D-branes. This resolution has implications for the conserved charges carried by the D-branes, which he computes for the cases studied in chapter 2. In chapter 5 he uses intersecting brane configurations to study three dimensional supersymmetric gauge theories. There is also a mirror symmetry there that, among other things, exchanges classical and quantum mechanical quantities of a (mirror) pair of theories. It has an elegant realization in term of a symmetry of string theory involving D-branes. The author employs it to study a wide class of 3d models. He also predicts new mirror pairs and unconventional 3d field theories without Lagrangian descriptions.

  13. Nonperturbative measurement of the local magnetic field using pulsed polarimetry for fusion reactor conditions (invited).

    PubMed

    Smith, Roger J

    2008-10-01

    A novel diagnostic technique for the remote and nonperturbative sensing of the local magnetic field in reactor relevant plasmas is presented. Pulsed polarimetry [Patent No. 12/150,169 (pending)] combines optical scattering with the Faraday effect. The polarimetric light detection and ranging (LIDAR)-like diagnostic has the potential to be a local B(pol) diagnostic on ITER and can achieve spatial resolutions of millimeters on high energy density (HED) plasmas using existing lasers. The pulsed polarimetry method is based on nonlocal measurements and subtle effects are introduced that are not present in either cw polarimetry or Thomson scattering LIDAR. Important features include the capability of simultaneously measuring local T(e), n(e), and B(parallel) along the line of sight, a resiliency to refractive effects, a short measurement duration providing near instantaneous data in time, and location for real-time feedback and control of magnetohydrodynamic (MHD) instabilities and the realization of a widely applicable internal magnetic field diagnostic for the magnetic fusion energy program. The technique improves for higher n(e)B(parallel) product and higher n(e) and is well suited for diagnosing the transient plasmas in the HED program. Larger devices such as ITER and DEMO are also better suited to the technique, allowing longer pulse lengths and thereby relaxing key technology constraints making pulsed polarimetry a valuable asset for next step devices. The pulsed polarimetry technique is clarified by way of illustration on the ITER tokamak and plasmas within the magnetized target fusion program within present technological means.

  14. Transition Form Factors: A Unique Opportunity to Connect Non-Perturbative Strong Interactions to QCD

    SciTech Connect

    Gothe, Ralf W.

    2014-01-01

    Meson-photoproduction measurements and their reaction-amplitude analyses can establish more sensitively, and in some cases in an almost model-independent way, nucleon excitations and non-resonant reaction amplitudes. However, to investigate the strong interaction from explored — where meson-cloud degrees of freedom contribute substantially to the baryon structure — to still unexplored distance scales — where quark degrees of freedom dominate and the transition from dressed to current quarks occurs — we depend on experiments that allow us to measure observables that are probing this evolving non-perturbative QCD regime over its full range. Elastic and transition form factors are uniquely suited to trace this evolution by measuring elastic electron scattering and exclusive single-meson and double-pion electroproduction cross sections off the nucleon. These exclusive measurements will be extended to higher momentum transfers with the energy-upgraded CEBAF beam at JLab to study the quark degrees of freedom, where their strong interaction is responsible for the ground and excited nucleon state formations. After establishing unprecedented high-precision data, the imminent next challenge is a high-quality analysis to extract these relevant electrocoupling parameters for various resonances that then can be compared to state-of-the-art models and QCD-based calculations. Recent results will demonstrate the status of the analysis and of their theoretical descriptions, and an experimental and theoretical outlook will highlight what shall and may be achieved in the new era of the 12-GeV upgraded transition form factor program.

  15. Nonperturbative analysis of the two-level atom: Applications to multiphoton excitation

    SciTech Connect

    Duvall, R.E.; Valeo, E.J.; Oberman, C.R.

    1987-08-01

    Selective excitation in an atomic system subjected to a slowly varying external electromagnetic field is studied using a two-level model. Time evolution of the system is found using an approach which is nonperturbative in the field strength. There is no constraint to small values of the applied field, that is, the field (in appropriate energy units) need not be small compared to the difference in energies of the two levels. Rather, we prey upon the fact that the situation of interest to us is where the frequency of the exciting field is small compared to the frequency associated with the level difference. Transition probabilities and resonance conditions are found which circumscribe both the large and small field limits. In the weak field limit the previous results of high-order perturbation theory are readily recovered. For a monochromatic field the characteristic features of resonance excitation at high harmonic number of the applied field are (a) extremely narrow resonance widths and (b) shifts in resonance positions which are strong functions of field intensity. Because of this sensitivity, we are able to demonstrate that when slow temporal evolution of the field amplitude is taken into account (e.g., due to finite pulse duration) the appropriate mean excitation rate is that due to the uncorrelated contribution of many resonances. The results of this analysis are used to estimate excitation rates in a specific atomic system, Cd/sup 12 +/, which are then compared to multiphoton ionization rates. Our calculations suggest that the ionization rate exceeds the excitation rate by several orders of magnitude. 15 refs., 3 figs.

  16. Correlations in double parton distributions: perturbative and non-perturbative effects

    NASA Astrophysics Data System (ADS)

    Rinaldi, Matteo; Scopetta, Sergio; Traini, Marco; Vento, Vicente

    2016-10-01

    The correct description of Double Parton Scattering (DPS), which represents a background in several channels for the search of new Physics at the LHC, requires the knowledge of double parton distribution functions (dPDFs). These quantities represent also a novel tool for the study of the three-dimensional nucleon structure, complementary to the possibilities offered by electromagnetic probes. In this paper we analyze dPDFs using Poincaré covariant predictions obtained by using a Light-Front constituent quark model proposed in a recent paper, and QCD evolution. We study to what extent factorized expressions for dPDFs, which neglect, at least in part, two-parton correlations, can be used. We show that they fail in reproducing the calculated dPDFs, in particular in the valence region. Actually measurable processes at existing facilities occur at low longitudinal momenta of the interacting partons; to have contact with these processes we have analyzed correlations between pairs of partons of different kind, finding that, in some cases, they are strongly suppressed at low longitudinal momenta, while for other distributions they can be sizeable. For example, the effect of gluon-gluon correlations can be as large as 20 %. We have shown that these behaviors can be understood in terms of a delicate interference of non-perturbative correlations, generated by the dynamics of the model, and perturbative ones, generated by the model independent evolution procedure. Our analysis shows that at LHC kinematics two-parton correlations can be relevant in DPS, and therefore we address the possibility to study them experimentally.

  17. Piketty in the long run.

    PubMed

    Cowell, Frank A

    2014-12-01

    I examine the idea of 'the long run' in Piketty (2014) and related works. In contrast to simplistic interpretations of long-run models of income- and wealth-distribution Piketty (2014) draws on a rich economic analysis that models the intra- and inter-generational processes that underly the development of the wealth distribution. These processes inevitably involve both market and non-market mechanisms. To understand this approach, and to isolate the impact of different social and economic factors on inequality in the long run, we use the concept of an equilibrium distribution. However the long-run analysis of policy should not presume that there is an inherent tendency for the wealth distribution to approach equilibrium. © London School of Economics and Political Science 2014.

  18. Observations of running penumbral waves.

    NASA Technical Reports Server (NTRS)

    Zirin, H.; Stein, A.

    1972-01-01

    Quiet sunspots with well-developed penumbrae show running intensity waves with period running around 300 sec. The waves appear connected with umbral flashes of exactly half the period. Waves are concentric, regular, with velocity constant around 10 km/sec. They are probably sound waves and show intensity fluctuation in H alpha centerline or wing of 10 to 20%. The energy is tiny compared to the heat deficit of the umbra.

  19. The practical biomechanics of running.

    PubMed

    Adelaar, R S

    1986-01-01

    The foot and ankle is a complex structure made of many small bones with capsular and ligamentous constraints. The physiology, kinematics, and muscle interaction of the walking, jogging, and running cycles will be discussed and the current biomechanical literature reviewed. To analyze the pathologic state, one must be aware of the normal stresses and functions of the running cycle. This knowledge establishes a rational basis for the interpretation of problems in providing medical and orthotic treatment.

  20. Running of the running and entropy perturbations during inflation

    NASA Astrophysics Data System (ADS)

    van de Bruck, Carsten; Longden, Chris

    2016-07-01

    In single field slow-roll inflation, one expects that the spectral index ns-1 is first order in slow-roll parameters. Similarly, its running αs=d ns/d log k and the running of the running βs=d αs/d log k are second and third order and therefore expected to be progressively smaller, and usually negative. Hence, such models of inflation are in considerable tension with a recent analysis hinting that βs may actually be positive, and larger than αs. Motivated by this, in this work we ask the question of what kinds of inflationary models may be useful in achieving such a hierarchy of runnings, particularly focusing on two-field models of inflation in which the late-time transfer of power from isocurvature to curvature modes allows for a much more diverse range of phenomenology. We calculate the runnings due to this effect and briefly apply our results to assess the feasibility of finding |βs|≳|αs| in some specific models.

  1. Effects of running velocity on running kinetics and kinematics.

    PubMed

    Brughelli, Matt; Cronin, John; Chaouachi, Anis

    2011-04-01

    Sixteen semiprofessional Australian football players performed running bouts at incremental velocities of 40, 60, 80, and 100% of their maximum velocity on a Woodway nonmotorized force treadmill. As running velocity increased from 40 to 60%, peak vertical and peak horizontal forces increased by 14.3% (effect size [ES] = 1.0) and 34.4% (ES = 4.2), respectively. The changes in peak vertical and peak horizontal forces from 60 to 80% were 1.0% (ES = 0.05) and 21.0% (ES = 2.9), respectively. Finally, the changes in peak vertical and peak horizontal forces from 80% to maximum were 2.0% (ES = 0.1) and 24.3% (ES = 3.4). In addition, both stride frequency and stride length significantly increased with each incremental velocity (p < 0.05). Conversely, contact times and the vertical displacement of the center of mass significantly decreased with increased running velocity (p < 0.05). A significant positive correlation was found between horizontal force and maximum running velocity (r = 0.47). For the kinematic variables, only stride length was found to have a significant positive correlation with maximum running velocity (r = 0.66). It would seem that increasing maximal sprint velocity may be more dependent on horizontal force production as opposed to vertical force production.

  2. RHIC Au beam in Run 2014

    SciTech Connect

    Zhang, S. Y.

    2014-09-15

    Au beam at the RHIC ramp in run 2014 is reviewed together with the run 2011 and run 2012. Observed bunch length and longitudinal emittance are compared with the IBS simulations. The IBS growth rate of the longitudinal emittance in run 2014 is similar to run 2011, and both are larger than run 2012. This is explained by the large transverse emittance at high intensity observed in run 2012, but not in run 2014. The big improvement of the AGS ramping in run 2014 might be related to this change. The importance of the injector intensity improvement in run 2014 is emphasized, which gives rise to the initial luminosity improvement of 50% in run 2014, compared with the previous Au-Au run 2011. In addition, a modified IBS model, which is calibrated using the RHIC Au runs from 9.8 GeV/n to 100 GeV/n, is presented and used in the study.

  3. Bosonic particle-correlated states: A nonperturbative treatment beyond mean field

    NASA Astrophysics Data System (ADS)

    Jiang, Zhang; Tacla, Alexandre B.; Caves, Carlton M.

    2017-08-01

    Many useful properties of dilute Bose gases at ultralow temperature are predicted precisely by the (mean-field) product-state Ansatz, in which all particles are in the same quantum state. Yet, in situations where particle-particle correlations become important, the product Ansatz fails. To include correlations nonperturbatively, we consider a new set of states: the particle-correlated state of N =l ×n bosons is derived by symmetrizing the n -fold product of an l -particle quantum state. Quantum correlations of the l -particle state "spread out" to any subset of the N bosons by symmetrization. The particle-correlated states can be simulated efficiently for large N , because their parameter spaces, which depend on l , do not grow with n . Here we formulate and develop in great detail the pure-state case for l =2 , where the many-body state is constructed from a two-particle pure state. These paired wave functions, which we call pair-correlated states (PCS), were introduced by A. J. Leggett [Rev. Mod. Phys. 73, 307 (2001), 10.1103/RevModPhys.73.307] as a particle-number-conserving version of the Bogoliubov approximation. We present an iterative algorithm that solves for the reduced (marginal) density matrices (RDMs), i.e., the correlation functions, associated with PCS in time O (N ) . The RDMs can also be derived from the normalization factor of PCS, which is derived analytically in the large-N limit. To test the efficacy of PCS, we analyze the ground state of the two-site Bose-Hubbard model by minimizing the energy of the PCS state, both in its exact form and in its large-N approximate form, and comparing with the exact ground state. For N =1000 , the relative errors of the ground-state energy for both cases are within 10-5 over the entire parameter region from a single condensate to a Mott insulator. We present numerical results that suggest that PCS might be useful for describing the dynamics in the strongly interacting regime.

  4. Do recent observations of very large electromagnetic dissociation cross sections signify a transition towards non-perturbative QED?

    NASA Technical Reports Server (NTRS)

    Norbury, John W.

    1992-01-01

    The very large electromagnetic dissociation (EMD) cross section recently observed by Hill, Wohn, Schwellenbach, and Smith do not agree with Weizsacker-Williams (WW) theory or any simple modification thereof. Calculations are presented for the reaction probabilities for this experiment and the entire single and double nucleon removal EMD data set. It is found that for those few reactions where theory and experiment disagree, the probabilities are exceptionally large. This indicates that WW theory is not valid for these reactions and that one must consider higher order corrections and perhaps even a non-perturbative approach to quantum electrodynamics (QED).

  5. Frequency regulators for the nonperturbative renormalization group: A general study and the model A as a benchmark

    NASA Astrophysics Data System (ADS)

    Duclut, Charlie; Delamotte, Bertrand

    2017-01-01

    We derive the necessary conditions for implementing a regulator that depends on both momentum and frequency in the nonperturbative renormalization-group flow equations of out-of-equilibrium statistical systems. We consider model A as a benchmark and compute its dynamical critical exponent z . This allows us to show that frequency regulators compatible with causality and the fluctuation-dissipation theorem can be devised. We show that when the principle of minimal sensitivity (PMS) is employed to optimize the critical exponents η , ν , and z , the use of frequency regulators becomes necessary to make the PMS a self-consistent criterion.

  6. Frequency regulators for the nonperturbative renormalization group: A general study and the model A as a benchmark.

    PubMed

    Duclut, Charlie; Delamotte, Bertrand

    2017-01-01

    We derive the necessary conditions for implementing a regulator that depends on both momentum and frequency in the nonperturbative renormalization-group flow equations of out-of-equilibrium statistical systems. We consider model A as a benchmark and compute its dynamical critical exponent z. This allows us to show that frequency regulators compatible with causality and the fluctuation-dissipation theorem can be devised. We show that when the principle of minimal sensitivity (PMS) is employed to optimize the critical exponents η, ν, and z, the use of frequency regulators becomes necessary to make the PMS a self-consistent criterion.

  7. Beyond the rainbow: Effects from pion back-coupling

    SciTech Connect

    Fischer, Christian S.; Williams, Richard

    2008-10-01

    We investigate hadronic unquenching effects in light quarks and mesons. To this end, we take into account the back-coupling of the pion onto the quark propagator within the nonperturbative continuum framework of Schwinger-Dyson equations (SDE) and Bethe-Salpeter equations (BSE). We improve on a previous approach by explicitly solving both the coupled system of SDEs and BSEs in the complex plane and the normalization problem for Bethe-Salpeter kernels depending on the total momentum of the meson. As a result of our study, we find considerable unquenching effects in the spectrum of light pseudoscalar, vector and axial-vector mesons.

  8. Effects of boson dispersion in fermion-boson coupled systems

    NASA Astrophysics Data System (ADS)

    Motome, Yukitoshi; Kotliar, Gabriel

    2000-11-01

    We study the nonlinear feedback in a fermion-boson system using an extension of dynamical mean-field theory and the quantum Monte Carlo method. In the perturbative regimes (weak-coupling and atomic limits) the effective interaction among fermions increases as the width of the boson dispersion increases. In the strong-coupling regime away from the antiadiabatic limit, the effective interaction decreases as we increase the width of the boson dispersion. This behavior is closely related to complete softening of the boson field. We elucidate the parameters that control this nonperturbative region where fluctuations of the dispersive bosons enhance the delocalization of fermions.

  9. CDF Run 2 muon system

    SciTech Connect

    C. M. Ginsburg

    2004-02-05

    The CDF muon detection system for Run 2 of the Fermilab Tevatron is described. Muon stubs are detected for |{eta}| < 1.5, and are matched to tracks in the central drift chamber at trigger level 1 for |{eta}| < 1.25. Detectors in the |{eta}| < 1 central region, built for previous runs, have been enhanced to survive the higher rate environment and closer bunch spacing (3.5 {micro}sec to 396 nsec) of Run 2. Azimuthal gaps in the central region have been filled in. New detectors have been added to extend the coverage from |{eta}| < 1 to |{eta}| < 1.5, consisting of four layers of drift chambers covered with matching scintillators for triggering. The Level 1 Extremely Fast Tracker supplies matching tracks with measured p{sub T} for the muon trigger. The system has been in operation for over 18 months. Operating experience and reconstructed data are presented.

  10. Quasinormal modes of a scalar field in the Einstein-Gauss-Bonnet-AdS black hole background: Perturbative and nonperturbative branches

    NASA Astrophysics Data System (ADS)

    González, P. A.; Konoplya, R. A.; Vásquez, Yerko

    2017-06-01

    It has recently been found that quasinormal modes of asymptotically anti-de Sitter (AdS) black holes in theories with higher curvature corrections may help to describe the regime of intermediate 't Hooft coupling in the dual field theory. Here, we consider quasinormal modes of a scalar field in the background of spherical Gauss-Bonnet-anti-de Sitter (AdS) black holes. In general, the eigenvalues of wave equations are found here numerically, but at a fixed Gauss-Bonnet constant α =R2/2 (where R is the AdS radius), an exact solution of the scalar field equation has been obtained. Remarkably, the purely imaginary modes, which are usually appropriate only to some gravitational perturbations, were found here even for a test scalar field. These purely imaginary modes of the Einstein-Gauss-Bonnet theory do not have the Einsteinian limits, because their damping rates grow, when α is decreasing. Thus, these modes are nonperturbative in α . The real oscillation frequencies of the perturbative branch are linearly related to their Schwarzschild-AdS limits Re (ωG B)=Re (ωSAdS)(1 +K (D )(α /R2)) , where D is the number of spacetime dimensions. Comparison of the analytical formula with the frequencies found by the shooting method allows us to test the latter. In addition, we found exact solutions to the master equations for gravitational perturbations at α =R2/2 and observed that for the scalar type of gravitational perturbations an eikonal instability develops.

  11. [Stress fracture after changing to barefoot running].

    PubMed

    Christensen, Mikkel

    2014-12-15

    Barefoot running is increasing in popularity but little is known about the implications in respect to injuries. It has been proposed that barefoot running is associated with a decrease in running injuries as it represents a more natural way of running. A 50-year-old runner with a weekly running distance of 50 km presented suffering from a stress fracture of the second metatarsal after six weeks of intensive barefoot running.

  12. Running cosmological constant with observational tests

    NASA Astrophysics Data System (ADS)

    Geng, Chao-Qiang; Lee, Chung-Chi; Zhang, Kaituo

    2016-09-01

    We investigate the running cosmological constant model with dark energy linearly proportional to the Hubble parameter, Λ = σH +Λ0, in which the ΛCDM limit is recovered by taking σ = 0. We derive the linear perturbation equations of gravity under the Friedmann-Lemaïtre-Robertson-Walker cosmology, and show the power spectra of the CMB temperature and matter density distribution. By using the Markov chain Monte Carlo method, we fit the model to the current observational data and find that σH0 /Λ0 ≲ 2.63 ×10-2 and 6.74 ×10-2 for Λ (t) coupled to matter and radiation-matter, respectively, along with constraints on other cosmological parameters.

  13. Non-perturbative scale evolution of four-fermion operators in two-flavour QCD

    NASA Astrophysics Data System (ADS)

    Herdoiza, Gregorio

    2006-12-01

    We apply finite-size recursion techniques based on the Schrödinger functional formalism to de- termine the renormalization group running of four-fermion operators which appear in the S = 2 effective weak Hamiltonian of the Standard Model. Our calculations are done using O(a) im- proved Wilson fermions with Nf = 2 dynamical flavours. Preliminary results are presented for the four-fermion operator which determines the BK -parameter in tmQCD.

  14. Teaching Bank Runs through Films

    ERIC Educational Resources Information Center

    Flynn, David T.

    2009-01-01

    The author advocates the use of films to supplement textbook treatments of bank runs and panics in money and banking or general banking classes. Modern students, particularly those in developed countries, tend to be unfamiliar with potential fragilities of financial systems such as a lack of deposit insurance or other safety net mechanisms. Films…

  15. Is Technology Running the Campus?

    ERIC Educational Resources Information Center

    Abramson, Paul

    1999-01-01

    Discusses survey results from 269 colleges, including 96 two- year, 85 four-year, and 88 universities about their use of technology in running and operating their facilities. Results show that colleges get high marks for thinking about automating various facility functions, but low marks on implementation. Technology use in security, building…

  16. Non-perturbative modelling of energetic particle effects on resistive wall mode: Anisotropy and finite orbit widtha)

    NASA Astrophysics Data System (ADS)

    Liu, Yueqiang; Chapman, I. T.; Graves, J. P.; Hao, G. Z.; Wang, Z. R.; Menard, J. E.; Okabayashi, M.; Strait, E. J.; Turnbull, A.

    2014-05-01

    A non-perturbative magnetohydrodynamic-kinetic hybrid formulation is developed and implemented into the MARS-K code [Liu et al., Phys. Plasmas 15, 112503 (2008)] that takes into account the anisotropy and asymmetry [Graves et al., Nature Commun. 3, 624 (2012)] of the equilibrium distribution of energetic particles (EPs) in particle pitch angle space, as well as first order finite orbit width (FOW) corrections for both passing and trapped EPs. Anisotropic models, which affect both the adiabatic and non-adiabatic drift kinetic energy contributions, are implemented for both neutral beam injection and ion cyclotron resonant heating induced EPs. The first order FOW correction does not contribute to the precessional drift resonance of trapped particles, but generally remains finite for the bounce and transit resonance contributions, as well as for the adiabatic contributions from asymmetrically distributed passing particles. Numerical results for a 9MA steady state ITER plasma suggest that (i) both the anisotropy and FOW effects can be important for the resistive wall mode stability in ITER plasmas; and (ii) the non-perturbative approach predicts less kinetic stabilization of the mode, than the perturbative approach, in the presence of anisotropy and FOW effects for the EPs. The latter may partially be related to the modification of the eigenfunction of the mode by the drift kinetic effects.

  17. Non-perturbative modelling of energetic particle effects on resistive wall mode: Anisotropy and finite orbit width

    SciTech Connect

    Liu, Yueqiang Chapman, I. T.; Hao, G. Z.; Wang, Z. R.; Menard, J. E.; Okabayashi, M.; Strait, E. J.; Turnbull, A.

    2014-05-15

    A non-perturbative magnetohydrodynamic-kinetic hybrid formulation is developed and implemented into the MARS-K code [Liu et al., Phys. Plasmas 15, 112503 (2008)] that takes into account the anisotropy and asymmetry [Graves et al., Nature Commun. 3, 624 (2012)] of the equilibrium distribution of energetic particles (EPs) in particle pitch angle space, as well as first order finite orbit width (FOW) corrections for both passing and trapped EPs. Anisotropic models, which affect both the adiabatic and non-adiabatic drift kinetic energy contributions, are implemented for both neutral beam injection and ion cyclotron resonant heating induced EPs. The first order FOW correction does not contribute to the precessional drift resonance of trapped particles, but generally remains finite for the bounce and transit resonance contributions, as well as for the adiabatic contributions from asymmetrically distributed passing particles. Numerical results for a 9MA steady state ITER plasma suggest that (i) both the anisotropy and FOW effects can be important for the resistive wall mode stability in ITER plasmas; and (ii) the non-perturbative approach predicts less kinetic stabilization of the mode, than the perturbative approach, in the presence of anisotropy and FOW effects for the EPs. The latter may partially be related to the modification of the eigenfunction of the mode by the drift kinetic effects.

  18. Running free: embracing a healthy lifestyle through distance running.

    PubMed

    Shipway, Richard; Holloway, Immy

    2010-11-01

    Sport and leisure activity contribute to both health and quality of life. There is a dearth of qualitative studies on the lived experiences of active people, so the aim of this paper is to develop a deeper understanding of the experiences of one particular group of active leisure participants, distance runners, and to highlight the associated health and well-being benefits that result from participating in this increasingly popular form of active leisure. In doing so, this paper will briefly explore the potential opportunities and implications for sport and leisure policy and provision, and highlight examples of how distance running could positively contribute towards government objectives linked to tackling obesity levels, healthy living and physical well-being. It is suggested that similar benefits also exist across other forms of physical activity, exercise and sport. Qualitative methods of enquiry were adopted to understand the nature of the social world of long distance runners through interviews and observations, which were thematically analyzed. One of the key themes emerging from the data was the desire to embrace a healthy lifestyle, which then led to the emergence of four main sub-themes. The first was linked to the importance of seeking self-esteem and confirmation through running; second, an investigation of a selection of negative aspects associated with exercise addiction; third, the need to exercise among sport and leisure participants; and finally, an understanding of the concept of the 'running body'. Cautionary notes also identified negative aspects associated with exercise and physical activity. The findings highlight the potential role that distance running can play as an easily accessible and enjoyable leisure activity, one that can help facilitate increased participation in exercise and physical activity as an integral part of an active and healthy lifestyle.

  19. Higgs boson self-coupling from two-loop analysis

    SciTech Connect

    Alhendi, H. A.; Barakat, T.; Loqman, I. Gh.

    2010-09-01

    The scale invariant of the effective potential of the standard model at two loop is used as a boundary condition under the assumption that the two-loop effective potential approximates the full effective potential. This condition leads with the help of the renormalization-group functions of the model at two loop to an algebraic equation of the scalar self-coupling with coefficients that depend on the gauge and the top quark couplings. It admits only two real positive solutions. One of them, in the absence of the gauge and top quark couplings, corresponds to the nonperturbative ultraviolet fixed point of the scalar renormalization-group function and the other corresponds to the perturbative infrared fixed point. The dependence of the scalar coupling on the top quark and the strong couplings at two-loop radiative corrections is analyzed.

  20. Preventing Running Injuries through Barefoot Activity

    ERIC Educational Resources Information Center

    Hart, Priscilla M.; Smith, Darla R.

    2008-01-01

    Running has become a very popular lifetime physical activity even though there are numerous reports of running injuries. Although common theories have pointed to impact forces and overpronation as the main contributors to chronic running injuries, the increased use of cushioning and orthotics has done little to decrease running injuries. A new…

  1. Physiologic Responses to Treadmill and Water Running.

    ERIC Educational Resources Information Center

    Bishop, Phillip A.; And Others

    1989-01-01

    Presents results of a study of the physiological responses of uninjured runners to running on a treadmill and in water. Water running may lessen an injured athlete's rate of deconditioning, but indications are that the metabolic cost of water running is not significantly greater than that of treadmill running. (SM)

  2. Physiologic Responses to Treadmill and Water Running.

    ERIC Educational Resources Information Center

    Bishop, Phillip A.; And Others

    1989-01-01

    Presents results of a study of the physiological responses of uninjured runners to running on a treadmill and in water. Water running may lessen an injured athlete's rate of deconditioning, but indications are that the metabolic cost of water running is not significantly greater than that of treadmill running. (SM)

  3. Preventing Running Injuries through Barefoot Activity

    ERIC Educational Resources Information Center

    Hart, Priscilla M.; Smith, Darla R.

    2008-01-01

    Running has become a very popular lifetime physical activity even though there are numerous reports of running injuries. Although common theories have pointed to impact forces and overpronation as the main contributors to chronic running injuries, the increased use of cushioning and orthotics has done little to decrease running injuries. A new…

  4. Quantum heat current under non-perturbative and non-Markovian conditions: Applications to heat machines

    NASA Astrophysics Data System (ADS)

    Kato, Akihito; Tanimura, Yoshitaka

    2016-12-01

    We consider a quantum system strongly coupled to multiple heat baths at different temperatures. Quantum heat transport phenomena in this system are investigated using two definitions of the heat current: one in terms of the system energy and the other in terms of the bath energy. When we consider correlations among system-bath interactions (CASBIs)—which have a purely quantum mechanical origin—the definition in terms of the bath energy becomes different. We found that CASBIs are necessary to maintain the consistency of the heat current with thermodynamic laws in the case of strong system-bath coupling. However, within the context of the quantum master equation approach, both of these definitions are identical. Through a numerical investigation, we demonstrate this point for a non-equilibrium spin-boson model and a three-level heat engine model using the reduced hierarchal equations of motion approach under the strongly coupled and non-Markovian conditions. We observe the cyclic behavior of the heat currents and the work performed by the heat engine, and we find that their phases depend on the system-bath coupling strength. Through consideration of the bath heat current, we show that the efficiency of the heat engine decreases as the strength of the system-bath coupling increases, due to the CASBI contribution. In the case of a large system-bath coupling, the efficiency decreases further if the bath temperature is increased, even if the ratio of the bath temperatures is fixed, due to the discretized nature of energy eigenstates. This is also considered to be a unique feature of quantum heat engines.

  5. Quantum heat current under non-perturbative and non-Markovian conditions: Applications to heat machines.

    PubMed

    Kato, Akihito; Tanimura, Yoshitaka

    2016-12-14

    We consider a quantum system strongly coupled to multiple heat baths at different temperatures. Quantum heat transport phenomena in this system are investigated using two definitions of the heat current: one in terms of the system energy and the other in terms of the bath energy. When we consider correlations among system-bath interactions (CASBIs)-which have a purely quantum mechanical origin-the definition in terms of the bath energy becomes different. We found that CASBIs are necessary to maintain the consistency of the heat current with thermodynamic laws in the case of strong system-bath coupling. However, within the context of the quantum master equation approach, both of these definitions are identical. Through a numerical investigation, we demonstrate this point for a non-equilibrium spin-boson model and a three-level heat engine model using the reduced hierarchal equations of motion approach under the strongly coupled and non-Markovian conditions. We observe the cyclic behavior of the heat currents and the work performed by the heat engine, and we find that their phases depend on the system-bath coupling strength. Through consideration of the bath heat current, we show that the efficiency of the heat engine decreases as the strength of the system-bath coupling increases, due to the CASBI contribution. In the case of a large system-bath coupling, the efficiency decreases further if the bath temperature is increased, even if the ratio of the bath temperatures is fixed, due to the discretized nature of energy eigenstates. This is also considered to be a unique feature of quantum heat engines.

  6. A dynamical mechanism for large volumes with consistent couplings

    NASA Astrophysics Data System (ADS)

    Abel, Steven

    2016-11-01

    A mechanism for addressing the "decompactification problem" is proposed, which consists of balancing the vacuum energy in Scherk-Schwarzed theories against contributions coming from non-perturbative physics. Universality of threshold corrections ensures that, in such situations, the stable minimum will have consistent gauge couplings for any gauge group that shares the same N = 2 beta function for the bulk excitations as the gauge group that takes part in the minimisation. Scherk-Schwarz compactification from 6D to 4D in heterotic strings is discussed explicitly, together with two alternative possibilities for the non-perturbative physics, namely metastable SQCD vacua and a single gaugino condensate. In the former case, it is shown that modular symmetries gives various consistency checks, and allow one to follow soft-terms, playing a similar role to R-symmetry in global SQCD. The latter case is particularly attractive when there is nett Bose-Fermi degeneracy in the massless sector. In such cases, because the original Casimir energy is generated entirely by excited and/or non-physical string modes, it is completely immune to the non-perturbative IR physics. Such a separation between UV and IR contributions to the potential greatly simplifies the analysis of stabilisation, and is a general possibility that has not been considered before.

  7. Selective running tool for wells

    SciTech Connect

    Semar, J.E.

    1988-05-24

    A downhole running tool for positioning and locking tool support mandrels within landing nipples of thin production tubing string of a well is described comprising: (a) housing means adapted for connection to a tool string and forming an internal receptacle; (b) an elongated core member being disposed within the internal receptacle and being telescopically movable to collapsed and extended positions defined by spaced stops formed by the housing means, a portion of the elongated core member extending from the housing for connection with a tool support mandrel; and (c) releasable retainer means normally retaining the elongated core member at a substantially fixed set position within the internal receptacle and being released responsive to engagement with the landing nipple during upward movement of the downhole running tool to thus permit collapsing telescoping movement of the elongated core to a mandrel locating position within the internal receptacle.

  8. Running: Improving Form to Reduce Injuries.

    PubMed

    2015-08-01

    Running is often perceived as a good option for "getting into shape," with little thought given to the form, or mechanics, of running. However, as many as 79% of all runners will sustain a running-related injury during any given year. If you are a runner-casual or serious-you should be aware that poor running mechanics may contribute to these injuries. A study published in the August 2015 issue of JOSPT reviewed the existing research to determine whether running mechanics could be improved, which could be important in treating running-related injuries and helping injured runners return to pain-free running.

  9. The Hickory Run deer exclosure

    Treesearch

    Ted J. Grisez

    1959-01-01

    The damage that deer can do to both planted and natural tree seedlings is vividly demonstrated by a l/l0-acre fenced exclosure at Hickory Run State Park in Carbon County, Pennsylvania. Here, by comparing the growth of trees that have been browsed by deer with the growth of trees that have been protected from deer by the fence, one can see the injurious effects of...

  10. Running Jobs in the Vacuum

    NASA Astrophysics Data System (ADS)

    McNab, A.; Stagni, F.; Ubeda Garcia, M.

    2014-06-01

    We present a model for the operation of computing nodes at a site using Virtual Machines (VMs), in which VMs are created and contextualized for experiments by the site itself. For the experiment, these VMs appear to be produced spontaneously "in the vacuum" rather having to ask the site to create each one. This model takes advantage of the existing pilot job frameworks adopted by many experiments. In the Vacuum model, the contextualization process starts a job agent within the VM and real jobs are fetched from the central task queue as normal. An implementation of the Vacuum scheme, Vac, is presented in which a VM factory runs on each physical worker node to create and contextualize its set of VMs. With this system, each node's VM factory can decide which experiments' VMs to run, based on site-wide target shares and on a peer-to-peer protocol in which the site's VM factories query each other to discover which VM types they are running. A property of this system is that there is no gate keeper service, head node, or batch system accepting and then directing jobs to particular worker nodes, avoiding several central points of failure. Finally, we describe tests of the Vac system using jobs from the central LHCb task queue, using the same contextualization procedure for VMs developed by LHCb for Clouds.

  11. GASIFICATION TEST RUN TC06

    SciTech Connect

    Southern Company Services, Inc.

    2003-08-01

    This report discusses test campaign TC06 of the Kellogg Brown & Root, Inc. (KBR) Transport Reactor train with a Siemens Westinghouse Power Corporation (Siemens Westinghouse) particle filter system at the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama. The Transport Reactor is an advanced circulating fluidized-bed reactor designed to operate as either a combustor or a gasifier using a particulate control device (PCD). The Transport Reactor was operated as a pressurized gasifier during TC06. Test run TC06 was started on July 4, 2001, and completed on September 24, 2001, with an interruption in service between July 25, 2001, and August 19, 2001, due to a filter element failure in the PCD caused by abnormal operating conditions while tuning the main air compressor. The reactor temperature was varied between 1,725 and 1,825 F at pressures from 190 to 230 psig. In TC06, 1,214 hours of solid circulation and 1,025 hours of coal feed were attained with 797 hours of coal feed after the filter element failure. Both reactor and PCD operations were stable during the test run with a stable baseline pressure drop. Due to its length and stability, the TC06 test run provided valuable data necessary to analyze long-term reactor operations and to identify necessary modifications to improve equipment and process performance as well as progressing the goal of many thousands of hours of filter element exposure.

  12. Age and sex influences on running mechanics and coordination variability.

    PubMed

    Boyer, Katherine A; Freedman Silvernail, Julia; Hamill, Joseph

    2017-11-01

    The purpose of this study was to examine the impact of age on running mechanics separately for male and female runners and to quantify sex differences in running mechanics and coordination variability for older runners. Kinematics and kinetics were captured for 20 younger (10 male) and 20 older (10 male) adults running overground at 3.5 m · s(-1). A modified vector coding technique was used to calculate segment coordination variability. Lower extremity joint angles, moments and segment coordination variability were compared between age and sex groups. Significant sex-age interaction effects were found for heel-strike hip flexion and ankle in/eversion angles and peak ankle dorsiflexion angle. In older adults, mid-stance knee flexion angle, ankle inversion and abduction moments and hip abduction and external rotation moments differed by sex. Older compared with younger females had reduced coordination variability in the thigh-shank transverse plane couple but greater coordination variability for the shank rotation-foot eversion couple in early stance. These results suggest there may be a non-equivalent aging process in the movement mechanics for males and females. The age and sex differences in running mechanics and coordination variability highlight the need for sex-based analyses for future studies examining injury risk with age.

  13. Coupling in the Tevatron

    SciTech Connect

    Gelfand, N.M.

    1994-12-01

    The performance of the Fermilab Tevatron Collider at the commencement of run Ib was far below expectations. After a frustrating period of several months, a low-{beta} quad downstream of the interaction point at B0 was found to be rolled. This rolled quadrupole coupled the horizontal and vertical motion of the Tevatron beams. It also made matching the beam from the Main Ring to the Tevatron impossible, resulting in emittance blow up on injection. The net result of the roll was a significant reduction in the Tevatron luminosity. When the roll in the quadrupole was corrected the performance of the Tevatron improved dramatically. This note will discuss the experimental data indicating the presence of coupling and subsequent calculations which show how coupling an affect the luminosity. It is not intended to exhaust a discussion of coupling, which hopefully will be understood well enough to be discussed in a subsequent note.

  14. Using the Model Coupling Toolkit to couple earth system models

    USGS Publications Warehouse

    Warner, J.C.; Perlin, N.; Skyllingstad, E.D.

    2008-01-01

    Continued advances in computational resources are providing the opportunity to operate more sophisticated numerical models. Additionally, there is an increasing demand for multidisciplinary studies that include interactions between different physical processes. Therefore there is a strong desire to develop coupled modeling systems that utilize existing models and allow efficient data exchange and model control. The basic system would entail model "1" running on "M" processors and model "2" running on "N" processors, with efficient exchange of model fields at predetermined synchronization intervals. Here we demonstrate two coupled systems: the coupling of the ocean circulation model Regional Ocean Modeling System (ROMS) to the surface wave model Simulating WAves Nearshore (SWAN), and the coupling of ROMS to the atmospheric model Coupled Ocean Atmosphere Prediction System (COAMPS). Both coupled systems use the Model Coupling Toolkit (MCT) as a mechanism for operation control and inter-model distributed memory transfer of model variables. In this paper we describe requirements and other options for model coupling, explain the MCT library, ROMS, SWAN and COAMPS models, methods for grid decomposition and sparse matrix interpolation, and provide an example from each coupled system. Methods presented in this paper are clearly applicable for coupling of other types of models. ?? 2008 Elsevier Ltd. All rights reserved.

  15. Spheroidal close-coupling scheme to describe ionization processes in one-electron diatomic systems

    SciTech Connect

    Pons, B.

    2003-04-01

    We propose a molecular close-coupling expansion in terms of prolate spheroidal wave functions confined in an ellipsoidal box. We first implement the method for ionization of H{sub 2}{sup +} molecular ions, by linearly polarized strong and short laser pulses, in the nonperturbative regime and within the (fixed nuclei) Born-Oppenheimer approximation. We further analyze the adequacy of the method to reproduce both the bound and the continuum nonadiabatic processes in ion-atom collisions.

  16. Barefoot running: does it prevent injuries?

    PubMed

    Murphy, Kelly; Curry, Emily J; Matzkin, Elizabeth G

    2013-11-01

    Endurance running has evolved over the course of millions of years and it is now one of the most popular sports today. However, the risk of stress injury in distance runners is high because of the repetitive ground impact forces exerted. These injuries are not only detrimental to the runner, but also place a burden on the medical community. Preventative measures are essential to decrease the risk of injury within the sport. Common running injuries include patellofemoral pain syndrome, tibial stress fractures, plantar fasciitis, and Achilles tendonitis. Barefoot running, as opposed to shod running (with shoes), has recently received significant attention in both the media and the market place for the potential to promote the healing process, increase performance, and decrease injury rates. However, there is controversy over the use of barefoot running to decrease the overall risk of injury secondary to individual differences in lower extremity alignment, gait patterns, and running biomechanics. While barefoot running may benefit certain types of individuals, differences in running stance and individual biomechanics may actually increase injury risk when transitioning to barefoot running. The purpose of this article is to review the currently available clinical evidence on barefoot running and its effectiveness for preventing injury in the runner. Based on a review of current literature, barefoot running is not a substantiated preventative running measure to reduce injury rates in runners. However, barefoot running utility should be assessed on an athlete-specific basis to determine whether barefoot running will be beneficial.

  17. Determination of the b-quark Mass and Nonperturbative parameters in Semileptonic and Radiative Penguin Decays at BaBar

    SciTech Connect

    Tackmann, Kerstin; collaboration, for the BABAR

    2008-01-23

    Knowing the mass of the b-quark is essential to the study of the structure and decays of B mesons as well as to future tests of the Higgs mechanism of mass generation. We present recent preliminary measurements of the b-quark mass and related nonperturbative parameters from moments of kinematic distributions in charmed and charmless semileptonic and radiative penguin B decays. Their determination from charmless semileptonic B decays is the first measurement in this mode. The data were collected by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -}-collider at the Stanford Linear Accelerator Center at a center-of-momentum energy of 10:58 GeV.

  18. Higgs amplitude mode in the vicinity of a (2 +1 ) -dimensional quantum critical point: A nonperturbative renormalization-group approach

    NASA Astrophysics Data System (ADS)

    Rose, F.; Léonard, F.; Dupuis, N.

    2015-06-01

    We study the "Higgs" amplitude mode in the relativistic quantum O (N ) model in two space dimensions. Using the nonperturbative renormalization group and the Blaizot-Méndez-Galain-Wschebor approximation (which we generalize to compute four-point correlation functions), we compute the O (N ) -invariant scalar susceptibility at zero temperature in the vicinity of the quantum critical point. In the ordered phase, we find a well-defined Higgs resonance for N =2 and 3 and determine its universal properties. No resonance is found for N ≥4 . In the disordered phase, the spectral function exhibits a threshold behavior with no Higgs-like peak. We also show that for N =2 , the Higgs mode manifests itself as a very broad peak in the longitudinal susceptibility in spite of the infrared divergence of the latter. We compare our findings with results from quantum Monte Carlo simulations and ɛ =4 -(d +1 ) expansion near d =3 .

  19. Large O(m-2c) nonperturbative corrections to the inclusive rate of the decay B -> Xsγ

    NASA Astrophysics Data System (ADS)

    Voloshin, M. B.

    1997-02-01

    It is shown that the inclusive rate of the rare weak radiative decays B -> Xsγ contains a series of nonperturbative corrections, whose `short distance' scale is set by m-1c, rather than bym-1b . The first correction in this series is expressed through the chromomagnetic interaction of the b quark inside the B meson and the relative magnitude of the effect is determined by the ratio /m2c. Though the magnitude of this first correction is suppressed by a numerical coefficient, the sensitivity of the decay rate to the distance scale m-1c may significantly limit the accuracy of purely perturbative predictions for the rate.

  20. Complements to nonperturbative treatment of radiative damping effect in dielectronic recombination: {delta}n=2 transition in C IV

    SciTech Connect

    Stancalie, V.

    2005-10-01

    The primary purpose of the present work is to provide new refined results from nonperturbative treatment of the radiative damping effect in dielectronic recombination. The present results are used to test and confirm previously reported method [V. Stancalie, Phys. Plasmas 12, 043301 (2005)] taking full account of the electron collision and radiative processes in a consistent way, when radiation field is considered to all orders. This work refers to the 1s{sup 2}2s5s({sup 1}S) and 1s{sup 2}2p7s({sup 1}P{sup 0}) configurations, embedded in the electric dipole field of the 2s-2p core transition in Li-like C ion. Comparisons with previously reported results are shown. This data are believed to be the first demonstration of {delta}n=2 channel in dielectronic recombination of Li-like into Be-like C and are important in plasma diagnostics.

  1. Carbon-deuterium bonds as non-perturbative infrared probes of protein dynamics, electrostatics, heterogeneity, and folding.

    PubMed

    Zimmermann, Jörg; Romesberg, Floyd E

    2014-01-01

    Vibrational spectroscopy is uniquely able to characterize protein dynamics and microenvironmental heterogeneity because it possesses an inherently high temporal resolution and employs probes of ultimately high structural resolution-the bonds themselves. The use of carbon-deuterium (C-D) bonds as vibrational labels circumvents the spectral congestion that otherwise precludes the use of vibrational spectroscopy to proteins and makes the observation of single vibrations within a protein possible while being wholly non-perturbative. Thus, C-D probes can be used to site-specifically characterize conformational heterogeneity and thermodynamic stability. C-D probes are also uniquely useful in characterizing the electrostatic microenvironment experienced by a specific residue side chain or backbone due to its effect on the C-D absorption frequency. In this chapter we describe the experimental procedures required to use C-D bonds and FT IR spectroscopy to characterize protein dynamics, structural and electrostatic heterogeneity, ligand binding, and folding.

  2. Nonperturbative calculation of the London-van der Waals interaction potential

    NASA Astrophysics Data System (ADS)

    Berman, P. R.; Ford, G. W.; Milonni, P. W.

    2014-02-01

    The so-called remarkable formula [G. W. Ford, J. T. Lewis, and R. F. O'Connell, Phys. Rev. Lett. 55, 2273 (1985), 10.1103/PhysRevLett.55.2273] for the Helmholtz free energy is applied to the problem of determining the interaction potential to all orders in the coupling strength of a pair of oscillator dipoles interacting through the familiar dipole-dipole interaction of electrodynamics. Simple, straightforward calculations lead to expressions for (1) the London short-range potential, (2) the Casimir-Polder long-range potential, and (3) the potential at high temperature. Explicit results are shown for both the temperature dependence of the interaction potential and its deviation from the weak-coupling limit. It is stressed that the interaction potential is a change in free energy, not the energy; in particular, in the high temperature case, the change of energy is zero.

  3. Effect of Off-Diagonal Exciton-Phonon Coupling on Intramolecular Singlet Fission.

    PubMed

    Huang, Zhongkai; Fujihashi, Yuta; Zhao, Yang

    2017-07-20

    Intramolecular singlet fission (iSF) materials provide remarkable advantages in terms of tunable electronic structures, and quantum chemistry studies have indicated strong electronic coupling modulation by high frequency phonon modes. In this work, we formulate a microscopic model of iSF with simultaneous diagonal and off-diagonal coupling to high-frequency modes. A nonperturbative treatment, the Dirac-Frenkel time-dependent variational approach is adopted using the multiple Davydov trial states. It is shown that both diagonal and off-diagonal coupling can aid efficient singlet fission if excitonic coupling is weak, and fission is only facilitated by diagonal coupling if excitonic coupling is strong. In the presence of off-diagonal coupling, it is found that high frequency modes create additional fission channels for rapid iSF. Results presented here may help provide guiding principles for design of efficient singlet fission materials by directly tuning singlet-triplet interstate coupling.

  4. 40 CFR 258.26 - Run-on/run-off control systems.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... least the water volume resulting from a 24-hour, 25-year storm. (b) Run-off from the active portion of... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Run-on/run-off control systems. 258.26... FOR MUNICIPAL SOLID WASTE LANDFILLS Operating Criteria § 258.26 Run-on/run-off control systems. (a...

  5. 40 CFR 258.26 - Run-on/run-off control systems.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... least the water volume resulting from a 24-hour, 25-year storm. (b) Run-off from the active portion of... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Run-on/run-off control systems. 258.26... FOR MUNICIPAL SOLID WASTE LANDFILLS Operating Criteria § 258.26 Run-on/run-off control systems. (a...

  6. 40 CFR 258.26 - Run-on/run-off control systems.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... least the water volume resulting from a 24-hour, 25-year storm. (b) Run-off from the active portion of... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Run-on/run-off control systems. 258.26... FOR MUNICIPAL SOLID WASTE LANDFILLS Operating Criteria § 258.26 Run-on/run-off control systems. (a...

  7. A new approach to analytic, non-perturbative, gauge-invariant QCD renormalization is described, with applications to high energy elastic pp-scattering.

    NASA Astrophysics Data System (ADS)

    Fried, H. M.; Tsang, P. H.; Gabellini, Y.; Grandou, T.; Sheu, Y.-M.

    2016-11-01

    A new non-perturbative, gauge-invariant model QCD renormalization is applied to high energy elastic pp-scattering. The differential cross-section deduced from this model displays a diffraction dip that resembles those of experiments. Comparison with ISR and LHC data is currently underway.

  8. Variable Joint Elasticities in Running

    NASA Astrophysics Data System (ADS)

    Peter, Stephan; Grimmer, Sten; Lipfert, Susanne W.; Seyfarth, Andre

    In this paper we investigate how spring-like leg behavior in human running is represented at joint level. We assume linear torsion springs in the joints and between the knee and the ankle joint. Using experimental data of the leg dynamics we compute how the spring parameters (stiffness and rest angles) change during gait cycle. We found that during contact the joints reveal elasticity with strongly changing parameters and compare the changes of different parameters for different spring arrangements. The results may help to design and improve biologically inspired spring mechanisms with adjustable parameters.

  9. A Crack Runs Through It

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This 3-D image taken by the microscopic imager on the Mars Exploration Rover Opportunity shows a close-up of the center of the rock abrasion tool hole, ground into 'Bounce' on the rover's 66th sol on Mars. Features smaller than one-tenth of a millimeter (.004 inches) are visible. The observed area is a little over 3 centimeters (1.2 inches). The canyon-like crack that runs across the bottom half of the image is really only about 2 millimeters (about 0.08 inches) deep. Scientists are currently using a variety of instruments to study the chemical content of the rock.

  10. Leg stiffness of sprinters using running-specific prostheses.

    PubMed

    McGowan, Craig P; Grabowski, Alena M; McDermott, William J; Herr, Hugh M; Kram, Rodger

    2012-08-07

    Running-specific prostheses (RSF) are designed to replicate the spring-like nature of biological legs (bioL) during running. However, it is not clear how these devices affect whole leg stiffness characteristics or running dynamics over a range of speeds. We used a simple spring-mass model to examine running mechanics across a range of speeds, in unilateral and bilateral transtibial amputees and performance-matched controls. We found significant differences between the affected leg (AL) of unilateral amputees and both ALs of bilateral amputees compared with the bioL of non-amputees for nearly every variable measured. Leg stiffness remained constant or increased with speed in bioL, but decreased with speed in legs with RSPs. The decrease in leg stiffness in legs with RSPs was mainly owing to a combination of lower peak ground reaction forces and increased leg compression with increasing speeds. Leg stiffness is an important parameter affecting contact time and the force exerted on the ground. It is likely that the fixed stiffness of the prosthesis coupled with differences in the limb posture required to run with the prosthesis limits the ability to modulate whole leg stiffness and the ability to apply high vertical ground reaction forces during sprinting.

  11. The coordinated movement of the spine and pelvis during running.

    PubMed

    Preece, Stephen J; Mason, Duncan; Bramah, Christopher

    2016-02-01

    Previous research into running has demonstrated consistent patterns in pelvic, lumbar and thoracic motions between different human runners. However, to date, there has been limited attempt to explain why observed coordination patterns emerge and how they may relate to centre of mass (CoM) motion. In this study, kinematic data were collected from the thorax, lumbar spine, pelvis and lower limbs during over ground running in n=28 participants. These data was subsequently used to develop a theoretical understanding of the coordination of the spine and pelvis in all three body planes during the stance phase of running. In the sagittal plane, there appeared to be an antiphase coordinate pattern which may function to increase femoral inclination at toe off whilst minimising anterior-posterior accelerations of the CoM. In the medio-lateral direction, CoM motion appears to facilitate transition to the contralateral foot. However, an antiphase coordination pattern was also observed, most likely to minimise unnecessary accelerations of the CoM. In the transverse plane, motion of the pelvis was observed to lag slightly behind that of the thorax. However, it is possible that the close coupling between these two segments facilitates the thoracic rotation required to passively drive arm motion. This is the first study to provide a full biomechanical rationale for the coordination of the spine and pelvis during human running. This insight should help clinicians develop an improved understanding of how spinal and pelvic motions may contribute to, or result from, common running injuries.

  12. When the Well Runs Dry

    ERIC Educational Resources Information Center

    Williams, Robert H.

    1972-01-01

    Natural gas is viewed as an attractive fuel - low polluting, with low production and transportation costs. However, high demand, coupled with a decreased discovery rate for new gas reserves, is leading to a natural gas shortage. Other resources must be substituted with synthetic gas from coal and methane from organic wastes emerging as potential…

  13. When the Well Runs Dry

    ERIC Educational Resources Information Center

    Williams, Robert H.

    1972-01-01

    Natural gas is viewed as an attractive fuel - low polluting, with low production and transportation costs. However, high demand, coupled with a decreased discovery rate for new gas reserves, is leading to a natural gas shortage. Other resources must be substituted with synthetic gas from coal and methane from organic wastes emerging as potential…

  14. Effective leg stiffness in running.

    PubMed

    Blum, Yvonne; Lipfert, Susanne W; Seyfarth, Andre

    2009-10-16

    Leg stiffness is a common parameter used to characterize leg function during bouncing gaits, like running and hopping. In the literature, different methods to approximate leg stiffness based on kinetic and kinematic parameters are described. A challenging point in estimating leg stiffness is the definition of leg compression during contact. In this paper four methods (methods A-D) based on ground reaction forces (GRF) and one method (method E) relying on temporal parameters are described. Leg stiffness calculated by these five methods is compared with running patterns, predicted by the spring mass model. The best and simplest approximation of leg stiffness is method E. It requires only easily accessible parameters (contact time, flight time, resting leg length, body mass and the leg's touch down angle). Method D is of similar quality but additionally requires the time-dependent progression of the GRF. The other three methods show clear differences from the model predictions by over- or underestimating leg stiffness, especially at slow speeds. Leg stiffness is derived from a conceptual model of legged locomotion and does not exist without this model. Therefore, it is important to prove which experimental method is suited best for approximating the stiffness in a specific task. This will help to interpret the predictions of the conceptual model in comparison with experimental data.

  15. HVM capabilities of CPE run-to-run overlay control

    NASA Astrophysics Data System (ADS)

    Subramany, Lokesh; Chung, Woong Jae; Gutjahr, Karsten; Garcia-Medina, Miguel; Sparka, Christian; Yap, Lipkong; Demirer, Onur; Karur-Shanmugam, Ramkumar; Riggs, Brent; Ramanathan, Vidya; Robinson, John C.; Pierson, Bill

    2015-03-01

    With the introduction of N2x and N1x process nodes, leading-edge factories are facing challenging demands of shrinking design margins. Previously un-corrected high-order signatures, and un-compensated temporal changes of high-order signatures, carry an important potential for improvement of on-product overlay (OPO). Until recently, static corrections per exposure (CPE), applied separately from the main APC correction, have been the industry's standard for critical layers [1], [2]. This static correction is setup once per device and layer and then updated periodically or when a machine change point generates a new overlay signature. This is a non-ideal setup for two reasons. First, any drift or sudden shift in tool signature between two CPE update periods can cause worse OPO and a higher rework rate, or, even worse, lead to yield loss at end of line. Second, these corrections are made from full map measurements that can be in excess of 1,000 measurements per wafer [3]. Advanced overlay control algorithms utilizing Run-to-Run (R2R) CPE can be used to reduce the overlay signatures on product in High Volume Manufacturing (HVM) environments. In this paper, we demonstrate the results of a R2R CPE control scheme in HVM. The authors show an improvement up to 20% OPO Mean+3Sigma values on several critical immersion layers at the 28nm and 14 nm technology nodes, and a reduction of out-of-spec residual points per wafer (validated on full map). These results are attained by closely tracking process tool signature changes by means of APC, and with an affordable metrology load which is significantly smaller than full wafer measurements.

  16. The Influence of External Perturbations on Running Kinematics and Muscle Activity Before and After Accommodation

    PubMed Central

    Haudum, Anita; Birklbauer, Jürgen; Müller, Erich

    2012-01-01

    In the current study, the running pattern of the lower extremity was examined while being perturbed through tubes attached between the ankles and the lower back to analyze influences on the running pattern variability before and after a varied running intervention. 3D-kinematics, joint coupling and electromyography (EMG), as well as their variability, were analyzed in ten healthy male participants during treadmill running (10.5 km·h-1). Pre- and post-tests each consisted of 2 x 30 min treadmill running (one with and one without tubes). The results showed major acute effects on EMG and kinematics, as well as joint coordination variability, due to the constraints (p < 0.05). After the intervention, a process of normalization of most kinematic and EMG parameters occurred; however, EMG variability, kinematic variability and joint coordination variability were reduced during tube running below normal running level (p < 0.05). The findings further indicate rapid kinematic adaptations while muscle activity appears to require longer practice to adapt. The constraint serves to acutely increase variability, but may lead to reduced variability when applied for a longer period of time. Key points Normalization of the EMG variability after the training intervention during running with the dynamic constraint Joint coupling variability was reduced after practice intervention during constrained running Kinematic adaptations happen fast while muscle activity requires longer practice Sublevels (i.e., EMGs) were more influenced by the constraint than the macroscopic kinematics. PMID:24150066

  17. Ventilatory Threshold, Running Economy and Distance Running Performance of Trained Athletes.

    ERIC Educational Resources Information Center

    Powers, Scott K.; And Others

    1983-01-01

    In an attempt to identify physiological factors that account for success in distance running, researchers evaluated relationships among ventilatory threshold, running economy, and distance running performance. Subjects were trained male runners with similar maximal aerobic power. (Authors/PP)

  18. Running Parallel Discrete Event Simulators on Sierra

    SciTech Connect

    Barnes, P. D.; Jefferson, D. R.

    2015-12-03

    In this proposal we consider porting the ROSS/Charm++ simulator and the discrete event models that run under its control so that they run on the Sierra architecture and make efficient use of the Volta GPUs.

  19. Is Running Bad for Your Knees?

    MedlinePlus

    ... https://medlineplus.gov/news/fullstory_162903.html Is Running Bad for Your Knees? Study suggests it may ... THURSDAY, Jan. 5, 2017 (HealthDay News) -- Everybody believes running can leave you sore and swollen, right? Well, ...

  20. Running as an Adjunct to Psychotherapy.

    ERIC Educational Resources Information Center

    Leer, Frederic

    1980-01-01

    Physical benefits of running have been highly publicized. Explores the equally valuable psychological benefits to be derived from running and examines how mastering a physical skill can be generalized to mastery in other areas of life. (Author)

  1. A detailed study of nonperturbative solutions of two-body Dirac equations

    SciTech Connect

    Crater, H.W.; Becker, R.L.; Wong, C.Y.; Van Alstine, P.

    1992-12-01

    In quark model calculations of the meson spectrums fully covariant two-body Dirac equations dictated by Dirac's relativistic constraint mechanics gave a good fit to the entire meson mass spectrum for light quark mesons as well as heavy quark mesons with constituent world scalar and vector potentials depending on just one or two parameters. In this paper, we investigate the properties of these equations that made them work so well by solving them numerically for quantum electrodynamics (QED) and related field theories. The constraint formalism generates a relativistic quantum mechanics defined by two coupled Dirac equations on a sixteen component wave function which contain Lorentz covariant constituent potentials that are initially undetermined. An exact Pauli reduction leads to a second order relativistic Schroedinger-like equation for a reduced eight component wave function determined by an effective interaction -- the quasipotential. We first determine perturbatively to lowest order the relativistic quasipotential for the Schroedinger-like equation by comparing that form with one derived from the Bethe-Salpeter equation. Insertion of this perturbative information into the minimal interaction structures of the two-body Dirac equations then completely determines their interaction structures. Then we give a procedure for constructing the full sixteen component solution to our coupled first-order Dirac equations from a solution of the second order equation for the reduced wave function. Next, we show that a perturbative treatment of these equations yields the standard spectral results for QED and related interactions.

  2. Running Patterns of Highly Skilled Distance Runners.

    ERIC Educational Resources Information Center

    Dunetts, Michael J.; Dillman, Charles J.

    The biomechanical elements inherent in the running styles of Olympic-level athletes were examined in order to obtain a range of parameter values for specific running velocities. Forty-eight athletes participated in middle and long distance running events that were filmed and later analyzed to determine the relationship between the physical…

  3. Running Patterns of Highly Skilled Distance Runners.

    ERIC Educational Resources Information Center

    Dunetts, Michael J.; Dillman, Charles J.

    The biomechanical elements inherent in the running styles of Olympic-level athletes were examined in order to obtain a range of parameter values for specific running velocities. Forty-eight athletes participated in middle and long distance running events that were filmed and later analyzed to determine the relationship between the physical…

  4. An Epidemiologic Perspective. Does Running Cause Osteoarthritis?

    ERIC Educational Resources Information Center

    Eichner, Edward R.

    1989-01-01

    A review of literature on exercise and arthritis considers relevant epidemiologic and experimental studies of animals and humans, focusing on the relationship between running and osteoarthritis. No conclusive evidence exists that running causes osteoarthritis; research trends suggest that running may slow the functional aspects of musculoskeletal…

  5. An Epidemiologic Perspective. Does Running Cause Osteoarthritis?

    ERIC Educational Resources Information Center

    Eichner, Edward R.

    1989-01-01

    A review of literature on exercise and arthritis considers relevant epidemiologic and experimental studies of animals and humans, focusing on the relationship between running and osteoarthritis. No conclusive evidence exists that running causes osteoarthritis; research trends suggest that running may slow the functional aspects of musculoskeletal…

  6. Head injury from a bungee run.

    PubMed

    Singh, Pankaj; Convery, Fiona; Watt, Michael; Fulton, Ailsa; McKinstry, Steven; Flannery, Thomas

    2012-04-01

    An adaptation of bungee jumping, 'bungee running', involves participants attempting to run as far as they can whilst connected to an elastic rope which is anchored to a fixed point. Usually considered a safe recreational activity, we report a potentially life-threatening head injury following a bungee running accident.

  7. Adding run history to CLIPS

    NASA Technical Reports Server (NTRS)

    Tuttle, Sharon M.; Eick, Christoph F.

    1991-01-01

    To debug a C Language Integrated Production System (CLIPS) program, certain 'historical' information about a run is needed. It would be convenient for system builders to have the capability to request such information. We will discuss how historical Rete networks can be used for answering questions that help a system builder detect the cause of an error in a CLIPS program. Moreover, the cost of maintaining a historical Rete network is compared with that for a classical Rete network. We will demonstrate that the cost for assertions is only slightly higher for a historical Rete network. The cost for handling retraction could be significantly higher; however, we will show that by using special data structures that rely on hashing, it is also possible to implement retractions efficiently.

  8. Future Intent to Run and Running Performance of Students Exposed to a Traditional versus an Autonomy Supportive Motivational Running Program

    PubMed Central

    Silva, Andrea; Hannon, James C.; Shultz, Barry; Podlog, Leslie

    2013-01-01

    Background. The study's primary purpose was to investigate whether an autonomy supportive motivational climate in a running program would increase future running intent among high school students. A secondary purpose was to examine whether the program would increase individual performance in the Cooper 12-minute run. Methods. Students participated in a 4-month running intervention program which included four timed runs, one per month, and a future intent questionnaire prior to the start of the timed runs and following the last run. Results. Factorial repeated measures ANOVA revealed significance regarding future intent (P = .026) at both schools. Factorial repeated measures ANOVA indicated differences between the runs at both schools (P < .001). Paired samples t-tests were conducted to look at significance with paired runs. Results revealed significance in two of the six pairs at the treatment school, notably between the first and last timed runs (P = .004). Only one pair was found to be significant (P < .001) with the control school. Conclusion. At both schools, the overall number of laps increased as well as future intent to run scores. The results do not support evidence of a greater effect from the autonomy supportive environment over a traditional environment. PMID:24236280

  9. Dynamic gearing in running dogs.

    PubMed

    Carrier, D R; Gregersen, C S; Silverton, N A

    1998-12-01

    Dynamic gearing is a mechanism that has been suggested to enhance the performance of skeletal muscles by maintaining them at the shortening velocities that maximize their power or efficiency. We investigated this hypothesis in three domestic dogs during trotting and galloping. We used ground force recordings and kinematic analysis to calculate the changes in gear ratio that occur during the production of the external work of locomotion. We also monitored length changes of the vastus lateralis muscle, an extensor muscle of the knee, using sonomicrometry in four additional dogs to determine the nature and rate of active shortening of this muscle. During both trotting and galloping, the gear ratios of the extensor muscles of the elbow, wrist and ankle joints were relatively constant early in limb support, but decreased rapidly during the second half of support. The gear ratio at the hip exerted an extensor moment initially, but decreased throughout limb support and became negative midway through support. This pattern of decreasing gear ratio during the second half of support indicates that dynamic gearing does not maximize muscle power or efficiency at the elbow, wrist, hip and ankle joints. In contrast, the extensor muscles of the shoulder and knee joints exhibited an increase in gear ratio during limb support. In two dogs, the vastus lateralis muscle shortened at a relatively constant rate of 3.7-4 lengths s-1 during intermediate-speed galloping. This pattern of increasing gear ratio and constant velocity of muscle shortening at the knee joint is consistent with the hypothesis of dynamic gearing. Given the amount of work done at the knee and shoulder joints of running dogs, dynamic gearing may contribute to the economy of constant-speed running and may be important to integrated limb function.

  10. Tissue vibration in prolonged running.

    PubMed

    Friesenbichler, Bernd; Stirling, Lisa M; Federolf, Peter; Nigg, Benno M

    2011-01-04

    The impact force in heel-toe running initiates vibrations of soft-tissue compartments of the leg that are heavily dampened by muscle activity. This study investigated if the damping and frequency of these soft-tissue vibrations are affected by fatigue, which was categorized by the time into an exhaustive exercise. The hypotheses were tested that (H1) the vibration intensity of the triceps surae increases with increasing fatigue and (H2) the vibration frequency of the triceps surae decreases with increasing fatigue. Tissue vibrations of the triceps surae were measured with tri-axial accelerometers in 10 subjects during a run towards exhaustion. The frequency content was quantified with power spectra and wavelet analysis. Maxima of local vibration intensities were compared between the non-fatigued and fatigued states of all subjects. In axial (i.e. parallel to the tibia) and medio-lateral direction, most local maxima increased with fatigue (supporting the first hypothesis). In anterior-posterior direction no systematic changes were found. Vibration frequency was minimally affected by fatigue and frequency changes did not occur systematically, which requires the rejection of the second hypothesis. Relative to heel-strike, the maximum vibration intensity occurred significantly later in the fatigued condition in all three directions. With fatigue, the soft tissue of the triceps surae oscillated for an extended duration at increased vibration magnitudes, possibly due to the effects of fatigue on type II muscle fibers. Thus, the protective mechanism of muscle tuning seems to be reduced in a fatigued muscle and the risk of potential harm to the tissue may increase. Copyright © 2010 Elsevier Ltd. All rights reserved.

  11. Strong coupling from hadronic τ decays: A critical appraisal

    NASA Astrophysics Data System (ADS)

    Boito, Diogo; Golterman, Maarten; Maltman, Kim; Peris, Santiago

    2017-02-01

    Several different analysis methods have been developed to determine the strong coupling via finite-energy sum-rule analyses of hadronic τ decay data. While most methods agree on the existence of the well-known ambiguity in the choice of a resummation scheme due to the slow convergence of QCD perturbation theory at the τ mass, there is an ongoing controversy over how to deal properly with nonperturbative effects. These are small, but not negligible, and include quark-hadron "duality violations" (i.e., resonance effects) which are not described by the operator product expansion (OPE). In one approach, an attempt is made to suppress duality violations enough that they might become negligible. The number of OPE parameters to be fit, however, then exceeds the number of available sum rules, necessitating an uncontrolled OPE truncation, in which a number of higher-dimension OPE contributions in general present in QCD are set to zero by hand. In the second approach, truncation of the OPE is avoided by construction, and duality violations are taken into account explicitly, using a physically motivated model. In this article, we provide a critical appraisal of a recent analysis employing the first approach and demonstrate that it fails to properly account for nonperturbative effects, making the resulting determination of the strong coupling unreliable. The second approach, in contrast, passes all self-consistency tests, and provides a competitive determination of the strong coupling from τ decays.

  12. Energy-momentum tensor on the lattice: Nonperturbative renormalization in Yang-Mills theory

    NASA Astrophysics Data System (ADS)

    Giusti, Leonardo; Pepe, Michele

    2015-06-01

    We construct an energy-momentum tensor on the lattice which satisfies the appropriate Ward identities (WIs) and has the right trace anomaly in the continuum limit. It is defined by imposing suitable WIs associated to the Poincaré invariance of the continuum theory. These relations come forth when the length of the box in the temporal direction is finite, and they take a particularly simple form if the coordinate and the periodicity axes are not aligned. We implement the method for the SU(3) Yang-Mills theory discretized with the standard Wilson action in the presence of shifted boundary conditions in the (short) temporal direction. By carrying out extensive numerical simulations, the renormalization constants of the traceless components of the tensor are determined with a precision of roughly half a percent for values of the bare coupling constant in the range 0 ≤g02≤1 .

  13. Biomechanics and analysis of running gait.

    PubMed

    Dugan, Sheila A; Bhat, Krishna P

    2005-08-01

    Physical activity, including running, is important to general health by way of prevention of chronic illnesses and their precursors. To keep runners healthy, it is paramount that one has sound knowledge of the biomechanics of running and assessment of running gait. More so, improving performance in competitive runners is based in sound training and rehabilitation practices that are rooted firmly in biomechanical principles. This article summarized the biomechanics of running and the means with which one can evaluate running gait. The gait assessment techniques for collecting and analyzing kinetic and kinematic data can provide insights into injury prevention and treatment and performance enhancement.

  14. Random Test Run Length and Effectiveness

    NASA Technical Reports Server (NTRS)

    Andrews, James H.; Groce, Alex; Weston, Melissa; Xu, Ru-Gang

    2008-01-01

    A poorly understood but important factor in many applications of random testing is the selection of a maximum length for test runs. Given a limited time for testing, it is seldom clear whether executing a small number of long runs or a large number of short runs maximizes utility. It is generally expected that longer runs are more likely to expose failures -- which is certainly true with respect to runs shorter than the shortest failing trace. However, longer runs produce longer failing traces, requiring more effort from humans in debugging or more resources for automated minimization. In testing with feedback, increasing ranges for parameters may also cause the probability of failure to decrease in longer runs. We show that the choice of test length dramatically impacts the effectiveness of random testing, and that the patterns observed in simple models and predicted by analysis are useful in understanding effects observed.

  15. Random Test Run Length and Effectiveness

    NASA Technical Reports Server (NTRS)

    Andrews, James H.; Groce, Alex; Weston, Melissa; Xu, Ru-Gang

    2008-01-01

    A poorly understood but important factor in many applications of random testing is the selection of a maximum length for test runs. Given a limited time for testing, it is seldom clear whether executing a small number of long runs or a large number of short runs maximizes utility. It is generally expected that longer runs are more likely to expose failures -- which is certainly true with respect to runs shorter than the shortest failing trace. However, longer runs produce longer failing traces, requiring more effort from humans in debugging or more resources for automated minimization. In testing with feedback, increasing ranges for parameters may also cause the probability of failure to decrease in longer runs. We show that the choice of test length dramatically impacts the effectiveness of random testing, and that the patterns observed in simple models and predicted by analysis are useful in understanding effects observed.

  16. A Star on the Run

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-10-01

    Usually stars that are born together tend to move together but sometimes stars can go rogue and run away from their original birthplace. A pair of astronomers have now discovered the first runaway red supergiant (RSG) ever identified in another galaxy. With a radial velocity discrepancy of 300 km/s, its also the fastest runaway massive star known. Discrepant Speeds: When massive stars form in giant molecular clouds, they create what are known as OB associations: groups of hot, massive, short-lived stars that have similar velocities because theyre moving through space together. But sometimes stars that appear to be part of an OB association dont have the same velocity as the rest of the group. These stars are called runaways.What causes an OB star to run away is still debated, but we know that a fairly significant fraction of OB stars are runaways. In spite of this, surprisingly few runaways have been found that are evolved massive stars i.e., the post-main-sequence state of OB stars. This is presumably because these evolved stars have had more time to move away from their birthplace, and its more difficult to identify a runaway without the context of its original group. An Evolved Runaway: Difference between observed velocity and expected velocity, plotted as a function of expected velocity. The black points are foreground stars. The red points are expected RSGs, clustered around a velocity difference of zero. The green pentagon is the runaway RSG J004330.06+405258.4. [Evans Massey 2015]Despite this challenge, a recent survey of RSGs in the galaxy M31 has led to the detection of a massive star on the run! Kate Evans (Lowell Observatory and California Institute of Technology) and Philip Massey (Lowell Observatory and Northern Arizona University) discovered that RSG J004330.06+405258.4 is moving through the Andromeda Galaxy with a radial velocity thats off by about 300 km/s from the radial velocity expected for its location.Evans and Massey discovered this rogue star

  17. Running boundary actions, Asymptotic Safety, and black hole thermodynamics

    NASA Astrophysics Data System (ADS)

    Becker, Daniel; Reuter, Martin

    2012-07-01

    Previous explorations of the Asymptotic Safety scenario in Quantum Einstein Gravity (QEG) by means of the effective average action and its associated functional renormalization group (RG) equation assumed spacetime manifolds which have no boundaries. Here we take a first step towards a generalization for non-trivial boundaries, restricting ourselves to action functionals which are at most of second order in the derivatives acting on the metric. We analyze two examples of truncated actions with running boundary terms: full fledged QEG within the single-metric Einstein-Hilbert truncation, augmented by a scale dependent Gibbons-Hawking surface term, and a bi-metric truncation for gravity coupled to scalar matter fields. The latter contains 17 running couplings, related to both bulk and boundary terms, whose beta-functions are computed in the induced gravity approximation (large N limit). We find that the bulk and the boundary Newton constant, pertaining to the Einstein-Hilbert and Gibbons-Hawking term, respectively, show opposite RG running; proposing a scale dependent variant of the ADM mass we argue that the running of both couplings is consistent with gravitational anti-screening. We discuss the status of the `bulk-boundary matching' usually considered necessary for a well defined variational principle within the functional RG framework, and we explain a number of conceptual issues related to the `zoo' of (Newton-type, for instance) coupling constants, for the bulk and the boundary, which result from the bi-metric character of the gravitational average action. In particular we describe a simple device for counting the number of field modes integrated out between the infrared cutoff scale and the ultraviolet. This method makes it manifest that, in an asymptotically safe theory, there are effectively no field modes integrated out while the RG trajectory stays in the scaling regime of the underlying fixed point. As an application, we investigate how the semiclassical

  18. What we can learn about running from barefoot running: an evolutionary medical perspective.

    PubMed

    Lieberman, Daniel E

    2012-04-01

    Barefoot running, which was how people ran for millions of years, provides an opportunity to study how natural selection adapted the human body to run. Because humans evolved to run barefoot, a barefoot running style that minimizes impact peaks and provides increased proprioception and foot strength, is hypothesized to help avoid injury, regardless of whether one is wearing shoes.

  19. On Coupled Stellar Luminosity and Gravitation

    NASA Astrophysics Data System (ADS)

    Neuenschwander, Dwight E.; McCully, C. V.

    2008-09-01

    We derive a analytic nonperturbative solution to the coupled field equations of general relativity and electrodynamics, for a star of initial mass Mo and lifetime-averaged luminosity L. We carry out our solution in familiar spherical coordinates, including an off-diagonal term in the metric tensor to allow for "frame dragging” caused by the radial flux of light. We then show how our metric can be transformed into a diagonal one; and how the "photon dust” electomagnetic stress tensor assumed by early investigators of this problem forms an approximation to our solution. We also estimate the magnitude of some of the small effects inferred by this model of radial frame dragging. We thank The Catalysts, an SNU science alumni organization, for its support.

  20. Coupling expert systems and simulation

    NASA Technical Reports Server (NTRS)

    Kawamura, K.; Beale, G.; Padalkar, S.; Rodriguez-Moscoso, J.; Hsieh, B. J.; Vinz, F.; Fernandez, K. R.

    1988-01-01

    A prototype coupled system called NESS (NASA Expert Simulation System) is described. NESS assists the user in running digital simulations of dynamic systems, interprets the output data to performance specifications, and recommends a suitable series compensator to be added to the simulation model.

  1. Spontaneous Pneumomediastinum from Running Sprints

    PubMed Central

    Turban, Joseph W.

    2010-01-01

    Spontaneous pneumomediastinum (SPM) is a fairly rare condition, caused by increased intrathoracic pressure, leading to free air in the mediastinal structures. Underlying lung conditions are associated with increased incidence of SPM, including asthma, interstitial lung disease, pneumonia, bullous lung, and radiation therapy for lung cancer. It is often preceded by Valsalva maneuvers, vomiting, coughing, asthma exacerbation, sneezing, childbirth, or intense physical activity. A case of SPM is presented in a 15-year-old male, who complained of throat pain and dyspnea while running sprints at football practice. Workup revealed SPM, and he was subsequently admitted and treated conservatively. His symptoms resolved in 2 days and he was discharged and suffered no further recurrences. In contrast to secondary pneumomediastinum, SPM is usually a benign condition although life-threatening conditions can rarely arise. Differentiating between these two conditions has important prognostic indications. There is a paucity of prospectively collected data regarding SPM, and considerable variation in recommendations concerning the extent of workup. PMID:20862351

  2. High impact running improves learning.

    PubMed

    Winter, Bernward; Breitenstein, Caterina; Mooren, Frank C; Voelker, Klaus; Fobker, Manfred; Lechtermann, Anja; Krueger, Karsten; Fromme, Albert; Korsukewitz, Catharina; Floel, Agnes; Knecht, Stefan

    2007-05-01

    Regular physical exercise improves cognitive functions and lowers the risk for age-related cognitive decline. Since little is known about the nature and the timing of the underlying mechanisms, we probed whether exercise also has immediate beneficial effects on cognition. Learning performance was assessed directly after high impact anaerobic sprints, low impact aerobic running, or a period of rest in 27 healthy subjects in a randomized cross-over design. Dependent variables comprised learning speed as well as immediate (1 week) and long-term (>8 months) overall success in acquiring a novel vocabulary. Peripheral levels of brain-derived neurotrophic factor (BDNF) and catecholamines (dopamine, epinephrine, norepinephrine) were assessed prior to and after the interventions as well as after learning. We found that vocabulary learning was 20 percent faster after intense physical exercise as compared to the other two conditions. This condition also elicited the strongest increases in BDNF and catecholamine levels. More sustained BDNF levels during learning after intense exercise were related to better short-term learning success, whereas absolute dopamine and epinephrine levels were related to better intermediate (dopamine) and long-term (epinephrine) retentions of the novel vocabulary. Thus, BDNF and two of the catecholamines seem to be mediators by which physical exercise improves learning.

  3. The MICE Run Control System

    NASA Astrophysics Data System (ADS)

    Hanlet, Pierrick; Mice Collaboration

    2014-06-01

    The Muon Ionization Cooling Experiment (MICE) is a demonstration experiment to prove the feasibility of cooling a beam of muons for use in a Neutrino Factory and/or Muon Collider. The MICE cooling channel is a section of a modified Study II cooling channel which will provide a 10% reduction in beam emittance. In order to ensure a reliable measurement, MICE will measure the beam emittance before and after the cooling channel at the level of 1%, or a relative measurement of 0.001. This renders MICE a precision experiment which requires strict controls and monitoring of all experimental parameters in order to control systematic errors. The MICE Controls and Monitoring system is based on EPICS and integrates with the DAQ, Data monitoring systems, and a configuration database. The new MICE Run Control has been developed to ensure proper sequencing of equipment and use of system resources to protect data quality. A description of this system, its implementation, and performance during recent muon beam data collection will be discussed.

  4. Take the monkey and run

    PubMed Central

    Phillips, Kimberley A.; Hambright, M. Karen; Hewes, Kelly; Schilder, Brian M.; Ross, Corinna N.; Tardif, Suzette D.

    2015-01-01

    Background The common marmoset (Callithrix jacchus) is a small, New World primate that is used extensively in biomedical and behavioral research. This short-lived primate, with its small body size, ease of handling, and docile temperament, has emerged as a valuable model for aging and neurodegenerative research. A growing body of research has indicated exercise, aerobic exercise especially, imparts beneficial effects to normal aging. Understanding the mechanisms underlying these positive effects of exercise, and the degree to which exercise has neurotherapeutic effects, is an important research focus. Thus, developing techniques to engage marmosets in aerobic exercise would have great advantages. New method Here we describe the marmoset exercise ball (MEB) paradigm: a safe (for both experimenter and subjects), novel and effective means to engage marmosets in aerobic exercise. We trained young adult male marmosets to run on treadmills for 30 min a day, 3 days a week. Results Our training procedures allowed us to engage male marmosets in this aerobic exercise within 4 weeks, and subjects maintained this frequency of exercise for 3 months. Comparison with existing methods To our knowledge, this is the first described method to engage marmosets in aerobic exercise. A major advantage of this exercise paradigm is that while it was technically forced exercise, it did not appear to induce stress in the marmosets. Conclusions These techniques should be useful to researchers wishing to address physiological responses of exercise in a marmoset model. PMID:25835199

  5. Analytic, non-perturbative, gauge-invariant quantum chromodynamics: Nucleon scattering and binding potentials

    SciTech Connect

    Fried, H.M.; Gabellini, Y.; Grandou, T.; Sheu, Y.-M.

    2013-11-15

    Removal of the quenched approximation in the mechanism which produced an analytic estimate of quark-binding potentials, along with a reasonable conjecture of the color structure of the nucleon formed by such a binding potential, is shown to generate an effective nucleon scattering and binding potential. The mass-scale factor on the order of the pion mass, previously introduced to define the transverse imprecision of quark coordinates, is again used, while the strength of the potential is proportional to the square of a renormalized quantum chromodynamics (QCD) coupling constant. The potential so derived does not include corrections due to spin, angular momentum, nucleon structure, and electroweak interactions; rather, it is qualitative in nature, showing how Nuclear Physics can arise from fundamental QCD. -- Highlights: •Nucleon–nucleon forces are derived qualitatively from basic realistic quantum chromodynamics. •An effective nucleon binding is obtained from the simplest unquenched approximation. •A model deuteron binding energy of −2.2 MeV follows with α{sub s,R}=12.5.

  6. Impact Accelerations of Barefoot and Shod Running.

    PubMed

    Thompson, M; Seegmiller, J; McGowan, C P

    2016-05-01

    During the ground contact phase of running, the body's mass is rapidly decelerated resulting in forces that propagate through the musculoskeletal system. The repetitive attenuation of these impact forces is thought to contribute to overuse injuries. Modern running shoes are designed to reduce impact forces, with the goal to minimize running related overuse injuries. Additionally, the fore/mid foot strike pattern that is adopted by most individuals when running barefoot may reduce impact force transmission. The aim of the present study was to compare the effects of the barefoot running form (fore/mid foot strike & decreased stride length) and running shoes on running kinetics and impact accelerations. 10 healthy, physically active, heel strike runners ran in 3 conditions: shod, barefoot and barefoot while heel striking, during which 3-dimensional motion analysis, ground reaction force and accelerometer data were collected. Shod running was associated with increased ground reaction force and impact peak magnitudes, but decreased impact accelerations, suggesting that the midsole of running shoes helps to attenuate impact forces. Barefoot running exhibited a similar decrease in impact accelerations, as well as decreased impact peak magnitude, which appears to be due to a decrease in stride length and/or a more plantarflexed position at ground contact. © Georg Thieme Verlag KG Stuttgart · New York.

  7. Relativistic stars in scalar-tensor theories with disformal coupling

    NASA Astrophysics Data System (ADS)

    Silva, Hector O.; Minamitsuji, Masato

    2017-01-01

    We discuss a general formulation to study the structure of slowly-rotating relativistic stars in a broad class of scalar-tensor theories including disformal coupling to matter. Our approach includes as particular cases theories with generalized kinetic terms and generic scalar field potentials, and contains theories with conformal coupling as particular limits. We propose a minimal model to investigate the role of the disformal coupling on the non-perturbative effect known as spontaneous scalarization, which causes relativistic star solutions in certain classes of scalar-tensor theories to differ dramatically from their general relativistic counterparts. Moreover, we show that the moment of inertia and compactness of stars are equation of state independent, which can potentially be used to constrain the model observationally.

  8. Transport signatures in topological systems coupled to ac fields

    NASA Astrophysics Data System (ADS)

    Ruocco, Leonard; Gómez-León, Álvaro

    2017-02-01

    We study the transport properties of a topological system coupled to an ac electric field by means of Floquet-Keldysh formalism. We consider a semi-infinite chain of dimers coupled to a semi-infinite metallic lead and obtain the density of states and current when the system is out of equilibrium. Our formalism is nonperturbative and allows us to explore, in the thermodynamic limit, a wide range of regimes for the ac field, arbitrary values of the coupling strength to the metallic contact and corrections to the wide-band limit (WBL). We find that hybridization with the contact can change the dimerization phase, and that the current dependence on the field amplitude can be used to discriminate between them. We also show the appearance of side bands and nonequilibrium zero-energy modes, characteristic of the Floquet systems. Our results directly apply to the stability of nonequilibrium topological phases, when transport measurements are used for their detection.

  9. Quantifying coordination and coordination variability in backward versus forward running: Implications for control of motion.

    PubMed

    Mehdizadeh, Sina; Arshi, Ahmed Reza; Davids, Keith

    2015-07-01

    The aims of this study were to compare coordination and coordination variability in backward and forward running and to investigate the effects of speed on coordination variability in both backward and forward running. Fifteen healthy male participants took part in this study to run forwards and backwards on a treadmill at 80%, 100% and 120% of their preferred running speeds. The coordinate data of passive reflective markers attached to body segments were recorded using motion capture systems. Coordination of shank-foot and thigh-shank couplings in sagittal plane was quantified using the continuous relative phase method. Coordination variability was calculated as the standard deviation of a coordination pattern over 50 strides. Cross-correlation coefficients and associated phase shifts were determined to quantify similarity in coordination patterns between forward and backward running. Our results demonstrated that the coordination pattern in a gait cycle of backward running was in reverse to that of forward running at all speeds implying that the same neural circuitry is responsible for regulating both forward and backward running gaits. In addition, results demonstrated that there was an average of approximately 11% phase shift between the coordination patterns of backward and forward running which indicates that a single underlying mechanism might be responsible for generating motor patterns in both forward and backward running. Finally, backward running had significantly higher magnitude of coordination variability compared to forward running, signifying that more degrees of freedom were involved in backward running. Speed however, did not affect coordination variability in either task. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Fast Ion Effects on Fishbones and n=1 Kinks in JET Simulated by a Non-perturbative NOVA-KN Code

    SciTech Connect

    N.N. Gorelenkov; C.Z. Cheng; V.G. Kiptily; M.J. Mantsinen; S.E. Sharapov; the JET-EFDA Contributors

    2004-10-28

    New global non-perturbative hybrid code, NOVA-KN, and simulations of resonant type modes in JET [Joint European Torus] plasmas driven by energetic H-minority ions are presented. The NOVA-KN code employs the ideal-MHD description for the background plasma and treats non-perturbatively the fast particle kinetic response, which includes the fast ion finite orbit width (FOW) effect. In particular, the n = 1 fishbone mode, which is in precession drift resonance with fast ions, is studied. The NOVA-KN code is applied to model an n = 1 (f = 50-80kHz) MHD activity observed recently in JET low density plasma discharges with high fast ion (H-minority) energy content generated during the ion cyclotron resonance heating (ICRH). This n = 1 MHD activity is interpreted as the instability of the n = 1 precession drift frequency fishbone modes.

  11. Internal, nonperturbing, radio frequency wave monitor reflectometer system on the DIII-D tokamak (abstract)a)

    NASA Astrophysics Data System (ADS)

    Lee, J. H.; Doyle, E. J.; Luhmann, N. C., Jr.; Peebles, W. A.; Petty, C. C.; Pinsker, R. I.; Rettig, C. L.; Rhodes, T. L.

    1995-01-01

    A new reflectometer system designed to monitor density fluctuations associated with rf waves has been successfully demonstrated on the DIII-D tokamak. It is a direct, internal, and nonperturbing diagnostic with access into the plasma core. This new diagnostic is motivated by a desire to improve understanding of rf wave physics issues, such as wave trajectory, heating mechanisms, rf wave deposition profile, and wave number, and is highly relevant to planned tokamaks such as ITER and TPX. This work is the first application of reflectometry to rf wave studies in a tokamak. Feedforward tracking receiver techniques are employed to remove frequency instabilities due to inherent drifts in the microwave sources and frequency pulling. In order to minimize spurious pickup of the rf pulse (˜60 MHz), heterodyne detection techniques are utilized, and all components are installed inside an rf shielding box. The system operates in the extraordinary mode (X mode) at 70 GHz. In this paper, a detailed description of the system, and data illustrating its successful operation will be presented.

  12. Novel nonperturbative approach for radiative B¯0(B¯s0)→J /ψ γ decays

    NASA Astrophysics Data System (ADS)

    Geng, Li-Sheng; Oset, Eulogio

    2016-07-01

    Radiative B¯ 0(B¯s 0)→J /ψ γ decays provide an interesting case to test our understanding of (non)perturbative QCD and eventually to probe physics beyond the standard model. Recently, the LHCb Collaboration reported an upper bound, updating the results of the BABAR Collaboration. Previous theoretical predictions based on QCD factorization or perturbative QCD have shown large variations due to different treatment of nonfactorizable contributions and meson-photon transitions. In this paper, we report on a novel approach to estimate the decay rates, which is based on a recently proposed model for B decays and the vector meson dominance hypothesis, widely tested in the relevant energy regions. The predicted branching ratios are Br [B¯ 0→J /ψ γ ]=(3.50 ±0.34-0.63+1.12)×10-8 and Br [B¯s 0→J /ψ γ ]=(7.20 ±0.68-1.30+2.31)×10-7 . The first uncertainty is systematic and the second is statistical, originating from the experimental B¯s 0→J /ψ ϕ branching ratio.

  13. Nonperturbative Chemical Imaging of Organelle Transport in Living Cells with Coherent Anti-Stokes Raman Scattering Microscopy

    PubMed Central

    Nan, Xiaolin; Potma, Eric O.; Xie, X. Sunney

    2006-01-01

    Nonperturbative monitoring of intracellular organelle transport in unstained living cells was achieved with coherent anti-Stokes Raman scattering (CARS) microscopy. To avoid possible interference with the organelle transport introduced by laser radiation, we first examined different illumination conditions. Using a new photodamage criterion based on morphological changes of the cells, we determined the threshold values of both pulse energy and average power at relevant wavelengths. Under excitation conditions much milder than the threshold levels, we were able to monitor the motions of lipid droplet (LD) organelles in steroidogenic mouse adrenal cortical (Y-1) cells with CARS microscopy in real time without perturbations to the cells. Particle tracking analyses revealed subdiffusion as well as active transport of LDs along microtubules. Interestingly, LD active transport is only present in Y-1 cells that rounded up in culture, a morphological change associated with steroidogenesis, suggesting possible involvements of LD active transport in the latter. Simultaneous imaging of LDs and mitochondria with CARS and two-photon fluorescence microscopy clearly showed that interactions between the two organelles could be facilitated by high LD motility. These observations demonstrate CARS microscopy as a powerful noninvasive imaging tool for studying dynamic processes in living cells. PMID:16632501

  14. Bifurcations of ion acoustic solitary and periodic waves in an electron-positron-ion plasma through non-perturbative approach

    NASA Astrophysics Data System (ADS)

    Saha, Asit; Chatterjee, Prasanta; Chatterjee

    2014-08-01

    Ion acoustic solitary waves and periodic waves in an unmagnetized plasma with superthermal (kappa-distributed) electrons and positrons are investigated through a non-perturbative approach. Model equations are transformed to a planar dynamical system. Then by using the bifurcations of phase portraits of this planar dynamical system, we have established that our model has solitary wave and periodic wave solutions. We have obtained two analytical solutions for these solitary and periodic waves depending on the parameters. From these solitary wave and periodic wave solutions, we have shown the combined effects of temperature ratio (σ) of electrons and positrons, spectral index (κ), speed of the traveling wave (v), and density ratio (p) of positrons and electrons on the characteristics of ion acoustic solitary and periodic waves. The spectral index, density ratio, speed of the traveling wave, and temperature ratio significantly affect the characteristics of ion acoustic solitary and periodic structures. The present study might be helpful to understand the salient features of nonlinear ion acoustic solitary and periodic structures in the interstellar medium.

  15. Endurance running and the evolution of Homo.

    PubMed

    Bramble, Dennis M; Lieberman, Daniel E

    2004-11-18

    Striding bipedalism is a key derived behaviour of hominids that possibly originated soon after the divergence of the chimpanzee and human lineages. Although bipedal gaits include walking and running, running is generally considered to have played no major role in human evolution because humans, like apes, are poor sprinters compared to most quadrupeds. Here we assess how well humans perform at sustained long-distance running, and review the physiological and anatomical bases of endurance running capabilities in humans and other mammals. Judged by several criteria, humans perform remarkably well at endurance running, thanks to a diverse array of features, many of which leave traces in the skeleton. The fossil evidence of these features suggests that endurance running is a derived capability of the genus Homo, originating about 2 million years ago, and may have been instrumental in the evolution of the human body form.

  16. Intrinsic Spin-Orbit Coupling in Superconducting Delta-Doped SrTiO3 Heterostructures

    SciTech Connect

    Bell, Christopher

    2011-08-19

    We report the violation of the Pauli limit due to intrinsic spin-orbit coupling in SrTiO{sub 3} heterostructures. Via selective doping down to a few nanometers, a two-dimensional superconductor is formed, geometrically suppressing orbital pair-breaking. The spin-orbit scattering is exposed by the robust in-plane superconducting upper critical field, exceeding the Pauli limit by a factor of 4. Transport scattering times several orders of magnitude higher than for conventional thin film superconductors enables a new regime to be entered, where spin-orbit coupling effects arise non-perturbatively.

  17. [Facts and fiction about running shoes].

    PubMed

    Schelde, Jacob

    2012-11-26

    Running as a means of exercise is becoming increasingly popular, but the rate of injury is very high among runners. To prevent running-related injuries much attention has been given the running shoe and its construction, particular its shock-absorbing capabilities and motion control features. It is recommended that running shoes should be purchased based on the runner's medial arch height and degree of pronation, and that the shoes should be changed frequently as their shock-absorbing capabilities decrease with usage. Randomized controlled trials and other studies in the scientific literature do not support these recommendations.

  18. Renal function abnormalities after marathon run and 16-kilometre long-distance run.

    PubMed

    Mydlík, Miroslav; Derzsiová, Katarína; Bohus, Branislav

    2012-01-01

    Renal functions were investigated in 29 marathon runners and in 20 runners in connection with 16-kilometre long-distance run. Body weight in runners decreased after marathon run in average of 1.3 +/- 0.5 kg and after 16-kilometre long-distance run in average of 1.4 +/- 0.4 kg. Blood pressure decreased after both runs. Total proteinuria and albuminuria significantly increased after both runs. The significant non-glomerular erythrocyturia was found in 9 runners after marathon run and in 3 runners after 16-km long-distance run. Total catalytic activity of serum creatine kinase, and its isoenzyme MB significantly increased after both runs. Increase of isoenzyme MB creatine kinase after runs was lower than 6% of total catalytic activity of creatine kinase. These increases were caused by rhabdomyolysis and were connected with myoglobinuria. Serum myoglobin significantly increased after marathon run and after 16-km run. Serum urea, creatinine, phosphorus and osmolality significantly increased after both runs. Calculated GFR significantly decreased after both runs. FE(Na), FE(Ca), FE(P), FE(OSM) and FE(H2O) significantly decreased after both runs. FE significantly increased after marathon run, but after 16-km run non-significantly decreased. Renal function abnormalities were caused by dehydration, microtraumas in extrarenal urinary tract, protein catabolism, decreased urinary excretion of osmotically active substances, rhabdomyolysis, activation of renin-angiotensin-aldosterone system and other factors. Renal function abnormalities in runners were already not present 2-6 days after marathon run and after 16-kilometre long-distance run and investigated parameters were in normal range or they did not significantly differ from the initial values.

  19. Running of αs and mb in the MSSM

    NASA Astrophysics Data System (ADS)

    Harlander, R. V.; Mihaila, L.; Steinhauser, M.

    2007-09-01

    A consistent evolution of the strong coupling constant αs from MZ to the grand unified theory (GUT) scale is presented, involving three-loop running and two-loop decoupling. The two-loop transition from the MS¯- to the DR¯-scheme is properly taken into account. In the second part of the paper, the bottom quark mass in the DR¯-scheme at the electroweak/supersymmetry (SUSY) scale is evaluated with four-loop accuracy. We find that the three-loop effects are comparable to the experimental uncertainty both for αs and mb.

  20. Motivational wheel running reverses cueing behavioural inflexibility in rodents.

    PubMed

    Chomiak, Taylor; Brown, Andrew R; Teskey, G Campbell; Hu, Bin

    2017-09-18

    Behavioural inflexibility and associated atypical learning behaviours are common clinical manifestations of the autism spectrum disorder (ASD) phenotype. Despite advances in our understanding of ASD, little research has been devoted to experimental interventions that might help to circumvent behavioural inflexibility in ASD. The current paper suggests that motivational locomotion in the form of wheel running can reduce behavioural inflexibility and learning impairments in an ASD rat model, and discusses how the strategy of reward-coupled locomotor activity may lead to clinical interventions for children with ASD.

  1. The CDF SVX II upgrade for the Tevatron Run II

    SciTech Connect

    Bortoletto, Daniela

    1997-04-01

    A microstrip silicon detector SVX II has been proposed for the upgrade of CDF to be installed in 1999 for Run II of the Tevatron. Three barrels of five layers of double-sided silicon microstrip detectors will cover the interaction region. A description of the project status will be presented. Emphasis will be given to the R&D program for silicon sensors which includes capacitance minimization, the study of coupling capacitor integrity, the operation of the detectors in conjunction with the SVXH and SVX2 readout chips in two beam tests and the determination of the detectors performance deterioration due to radiation damage.

  2. Distinct stages of adult hippocampal neurogenesis are regulated by running and the running environment.

    PubMed

    Bednarczyk, Matthew R; Hacker, Lindsay C; Fortin-Nunez, Stéphanie; Aumont, Anne; Bergeron, Raynald; Fernandes, Karl J L

    2011-12-01

    Hippocampal neurogenesis continues into adulthood in mammalian vertebrates, and in experimental rodent models it is powerfully stimulated by exposure to a voluntary running wheel. In this study, we demonstrate that exposure to a running wheel environment, in the absence of running, is sufficient to regulate specific aspects of hippocampal neurogenesis. Adult mice were provided with standard housing, housing enriched with a running wheel or housing enriched with a locked wheel (i.e., an environment comparable to that of running animals, without the possibility of engaging in running). We found that mice in the running wheel and locked wheel groups exhibited equivalent increases in proliferation within the neurogenic niche of the dentate gyrus; this included comparable increases in the proliferation of radial glia-like stem cells and the number of proliferating neuroblasts. However, only running animals displayed increased numbers of postmitotic neuroblasts and mature neurons. These results demonstrate that the running wheel environment itself is sufficient for promoting proliferation of early lineage hippocampal precursors, while running per se enables newly generated neuroblasts to survive and mature into functional hippocampal neurons. Thus, both running-independent and running-dependent stimuli are integral to running wheel-induced hippocampal neurogenesis.

  3. The Effect of Training in Minimalist Running Shoes on Running Economy.

    PubMed

    Ridge, Sarah T; Standifird, Tyler; Rivera, Jessica; Johnson, A Wayne; Mitchell, Ulrike; Hunter, Iain

    2015-09-01

    The purpose of this study was to examine the effect of minimalist running shoes on oxygen uptake during running before and after a 10-week transition from traditional to minimalist running shoes. Twenty-five recreational runners (no previous experience in minimalist running shoes) participated in submaximal VO2 testing at a self-selected pace while wearing traditional and minimalist running shoes. Ten of the 25 runners gradually transitioned to minimalist running shoes over 10 weeks (experimental group), while the other 15 maintained their typical training regimen (control group). All participants repeated submaximal VO2 testing at the end of 10 weeks. Testing included a 3 minute warm-up, 3 minutes of running in the first pair of shoes, and 3 minutes of running in the second pair of shoes. Shoe order was randomized. Average oxygen uptake was calculated during the last minute of running in each condition. The average change from pre- to post-training for the control group during testing in traditional and minimalist shoes was an improvement of 3.1 ± 15.2% and 2.8 ± 16.2%, respectively. The average change from pre- to post-training for the experimental group during testing in traditional and minimalist shoes was an improvement of 8.4 ± 7.2% and 10.4 ± 6.9%, respectively. Data were analyzed using a 2-way repeated measures ANOVA. There were no significant interaction effects, but the overall improvement in running economy across time (6.15%) was significant (p = 0.015). Running in minimalist running shoes improves running economy in experienced, traditionally shod runners, but not significantly more than when running in traditional running shoes. Improvement in running economy in both groups, regardless of shoe type, may have been due to compliance with training over the 10-week study period and/or familiarity with testing procedures. Key pointsRunning in minimalist footwear did not result in a change in running economy compared to running in traditional footwear

  4. Biomechanics of Distance Running: A Longitudinal Study

    ERIC Educational Resources Information Center

    Nelson, Richard C.; Gregor, Robert J.

    1976-01-01

    Training for distance running over a long period produces meaningful changes in the running mechanics of experienced runners, as revealed in this longitudinal study of the biomechanical components of stride length, stride rate, stride time, and support and nonsupport time. (MB)

  5. EnergyPlus Run Time Analysis

    SciTech Connect

    Hong, Tianzhen; Buhl, Fred; Haves, Philip

    2008-09-20

    EnergyPlus is a new generation building performance simulation program offering many new modeling capabilities and more accurate performance calculations integrating building components in sub-hourly time steps. However, EnergyPlus runs much slower than the current generation simulation programs. This has become a major barrier to its widespread adoption by the industry. This paper analyzed EnergyPlus run time from comprehensive perspectives to identify key issues and challenges of speeding up EnergyPlus: studying the historical trends of EnergyPlus run time based on the advancement of computers and code improvements to EnergyPlus, comparing EnergyPlus with DOE-2 to understand and quantify the run time differences, identifying key simulation settings and model features that have significant impacts on run time, and performing code profiling to identify which EnergyPlus subroutines consume the most amount of run time. This paper provides recommendations to improve EnergyPlus run time from the modeler?s perspective and adequate computing platforms. Suggestions of software code and architecture changes to improve EnergyPlus run time based on the code profiling results are also discussed.

  6. Minimum Wage Effects in the Longer Run

    ERIC Educational Resources Information Center

    Neumark, David; Nizalova, Olena

    2007-01-01

    Exposure to minimum wages at young ages could lead to adverse longer-run effects via decreased labor market experience and tenure, and diminished education and training, while beneficial longer-run effects could arise if minimum wages increase skill acquisition. Evidence suggests that as individuals reach their late 20s, they earn less the longer…

  7. Biomechanics of Distance Running: A Longitudinal Study

    ERIC Educational Resources Information Center

    Nelson, Richard C.; Gregor, Robert J.

    1976-01-01

    Training for distance running over a long period produces meaningful changes in the running mechanics of experienced runners, as revealed in this longitudinal study of the biomechanical components of stride length, stride rate, stride time, and support and nonsupport time. (MB)

  8. Running biomechanics: shorter heels, better economy.

    PubMed

    Scholz, M N; Bobbert, M F; van Soest, A J; Clark, J R; van Heerden, J

    2008-10-01

    Better running economy (i.e. a lower rate of energy consumption at a given speed) is correlated with superior distance running performance. There is substantial variation in running economy, even among elite runners. This variation might be due to variation in the storage and reutilization of elastic energy in tendons. Using a simple musculoskeletal model, it was predicted that the amount of energy stored in a tendon during a given movement depends more critically on moment arm than on mechanical properties of the tendon, with the amount of stored energy increasing as the moment arm gets smaller. Assuming a link between elastic energy reutilization and overall metabolic cost of running, a smaller moment arm should therefore be associated with superior running economy. This prediction was confirmed experimentally in a group of 15 highly trained runners. The moment arm of the Achilles tendon was determined from standardized photographs of the ankle, using the position of anatomical landmarks. Running economy was measured as the rate of metabolic energy consumption during level treadmill running at a speed of 16 km h(-1). A strong correlation was found between the moment arm of the Achilles tendon and running economy. Smaller muscle moment arms correlated with lower rates of metabolic energy consumption (r(2)=0.75, P<0.001).

  9. Teaching Bank Runs with Classroom Experiments

    ERIC Educational Resources Information Center

    Balkenborg, Dieter; Kaplan, Todd; Miller, Timothy

    2011-01-01

    Once relegated to cinema or history lectures, bank runs have become a modern phenomenon that captures the interest of students. In this article, the authors explain a simple classroom experiment based on the Diamond-Dybvig model (1983) to demonstrate how a bank run--a seemingly irrational event--can occur rationally. They then present possible…

  10. The Second Student-Run Homeless Shelter

    ERIC Educational Resources Information Center

    Seider, Scott C.

    2012-01-01

    From 1983-2011, the Harvard Square Homeless Shelter (HSHS) in Cambridge, Massachusetts, was the only student-run homeless shelter in the United States. However, college students at Villanova, Temple, Drexel, the University of Pennsylvania, and Swarthmore drew upon the HSHS model to open their own student-run homeless shelter in Philadelphia,…

  11. Run II data analysis on the grid

    SciTech Connect

    Igor Mandrichenko, Igor Terekhov and Frank Wurthwein

    2002-12-02

    In this document, we begin the technical design for the distributed RunII computing for CDF and D0. The present paper defines the three components of the data handling area of Run II computing, namely the Data Handling System, the Storage System and the Application. We outline their functionality and interaction between them. We identify necessary and desirable elements of the interfaces.

  12. Impact of Running Away on Girls' Pregnancy

    ERIC Educational Resources Information Center

    Thrane, Lisa E.; Chen, Xiaojin

    2012-01-01

    This study assessed the impact of running away on pregnancy in the subsequent year among U.S. adolescents. We also investigated interactions between running away and sexual assault, romance, and school disengagement. Pregnancy among females between 11 and 17 years (n = 6100) was examined utilizing the Longitudinal Study of Adolescent Health (Add…

  13. An analysis of running skyline load path.

    Treesearch

    Ward W. Carson; Charles N. Mann

    1971-01-01

    This paper is intended for those who wish to prepare an algorithm to determine the load path of a running skyline. The mathematics of a simplified approach to this running skyline design problem are presented. The approach employs assumptions which reduce the complexity of the problem to the point where it can be solved on desk-top computers of limited capacities. The...

  14. Separating Fact from Fiction: Increasing Running Speed

    ERIC Educational Resources Information Center

    Murgia, Carla

    2008-01-01

    From a biomechanical point of view, this article explores the common belief that one must increase stride length and frequency in order to increase running speed. The limb length, explosive power, and anaerobic capacity of the athlete, as well as the type of running (sprinting vs. long distance) must be considered before making such a…

  15. The Second Student-Run Homeless Shelter

    ERIC Educational Resources Information Center

    Seider, Scott C.

    2012-01-01

    From 1983-2011, the Harvard Square Homeless Shelter (HSHS) in Cambridge, Massachusetts, was the only student-run homeless shelter in the United States. However, college students at Villanova, Temple, Drexel, the University of Pennsylvania, and Swarthmore drew upon the HSHS model to open their own student-run homeless shelter in Philadelphia,…

  16. Impact of Running Away on Girls' Pregnancy

    ERIC Educational Resources Information Center

    Thrane, Lisa E.; Chen, Xiaojin

    2012-01-01

    This study assessed the impact of running away on pregnancy in the subsequent year among U.S. adolescents. We also investigated interactions between running away and sexual assault, romance, and school disengagement. Pregnancy among females between 11 and 17 years (n = 6100) was examined utilizing the Longitudinal Study of Adolescent Health (Add…

  17. Minimum Wage Effects in the Longer Run

    ERIC Educational Resources Information Center

    Neumark, David; Nizalova, Olena

    2007-01-01

    Exposure to minimum wages at young ages could lead to adverse longer-run effects via decreased labor market experience and tenure, and diminished education and training, while beneficial longer-run effects could arise if minimum wages increase skill acquisition. Evidence suggests that as individuals reach their late 20s, they earn less the longer…

  18. The Meaning of Running Away for Girls

    ERIC Educational Resources Information Center

    Peled, Einat; Cohavi, Ayelet

    2009-01-01

    Objective: The aim of this qualitative research was to understand how runaway girls perceive the processes involved in leaving home and the meaning they attribute to it. Method: Findings are based on in-depth interviews with 10 Israeli girls aged 13-17 with a history of running away from home. Results: The meaning of running away as it emerged…

  19. Separating Fact from Fiction: Increasing Running Speed

    ERIC Educational Resources Information Center

    Murgia, Carla

    2008-01-01

    From a biomechanical point of view, this article explores the common belief that one must increase stride length and frequency in order to increase running speed. The limb length, explosive power, and anaerobic capacity of the athlete, as well as the type of running (sprinting vs. long distance) must be considered before making such a…

  20. Teaching Bank Runs with Classroom Experiments

    ERIC Educational Resources Information Center

    Balkenborg, Dieter; Kaplan, Todd; Miller, Timothy

    2011-01-01

    Once relegated to cinema or history lectures, bank runs have become a modern phenomenon that captures the interest of students. In this article, the authors explain a simple classroom experiment based on the Diamond-Dybvig model (1983) to demonstrate how a bank run--a seemingly irrational event--can occur rationally. They then present possible…

  1. 40 CFR 92.126 - Test run.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Test run. 92.126 Section 92.126 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES Test Procedures § 92.126 Test run. (a) The following steps...

  2. Orthopaedic Perspective on Barefoot and Minimalist Running.

    PubMed

    Roth, Jonathan; Neumann, Julie; Tao, Matthew

    2016-03-01

    In recent years, there has been a movement toward barefoot and minimalist running. Advocates assert that a lack of cushion and support promotes a forefoot or midfoot strike rather than a rearfoot strike, decreasing the impact transient and stress on the hip and knee. Although the change in gait is theorized to decrease injury risk, this concept has not yet been fully elucidated. However, research has shown diminished symptoms of chronic exertional compartment syndrome and anterior knee pain after a transition to minimalist running. Skeptics are concerned that, because of the effects of the natural environment and the lack of a standardized transition program, barefoot running could lead to additional, unforeseen injuries. Studies have shown that, with the transition to minimalist running, there is increased stress on the foot and ankle and risk of repetitive stress injuries. Nonetheless, despite the large gap of evidence-based knowledge on minimalist running, the potential benefits warrant further research and consideration.

  3. Impedances and collective instabilities of the Tevatron at Run II

    SciTech Connect

    Ng, King-Yuen, FERMI

    1998-09-01

    The longitudinal and transverse coupling impedances of the Tevatron vacuum chamber are estimated and summed up. The resistive-wall impedances of the beam pipe and the laminations in the Lambertson magnets dominate below {approximately} 50 MHz. Then come the inductive parts of the bellows and BPM`s. The longitudinal and transverse collective instabilities, for both single bunch and multi bunches, are studied using Run II parameters. As expected the transverse coupled-bunch instability driven by the resistive-wall impedance is the most severe collective instability. However, it can be damped by a transverse damper designed for the correction of injection offsets. The power of such a damper has been studied.

  4. The CDF Run IIa Silicon Detector and Its Upgrade RunIIb

    SciTech Connect

    Cigdem Issever

    2003-12-19

    The CDF RunIIa silicon detector made the transition from commissioning to data taking. CDF's online and offline tracking algorithms, the performance of Layer 00 and the RunIIb silicon upgrade project are covered in this article.

  5. 40 CFR 258.26 - Run-on/run-off control systems.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... storm; (2) A run-off control system from the active portion of the landfill to collect and control at least the water volume resulting from a 24-hour, 25-year storm. (b) Run-off from the active portion...

  6. 40 CFR 258.26 - Run-on/run-off control systems.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... storm; (2) A run-off control system from the active portion of the landfill to collect and control at least the water volume resulting from a 24-hour, 25-year storm. (b) Run-off from the active portion...

  7. Phases of N=\\infty Gauge Theories on S^3 \\times S^1 and Nonperturbative Orbifold-orientifold Equivalences

    SciTech Connect

    Unsal, Mithat

    2007-03-06

    We study the phase diagrams of N = {infinity} vector-like, asymptotically free gauge theories as a function of volume, on S{sup 3} x S{sup 1}. The theories of interest are the ones with fermions in two index representations [adjoint, (anti)symmetric, and bifundamental abbreviated as QCD(adj), QCD(AS/S) and QCD(BF)], and are interrelated via orbifold or orientifold projections. The phase diagrams reveal interesting phenomena such as disentangled realizations of chiral and center symmetry, confinement without chiral symmetry breaking, zero temperature chiral transitions, and in some cases, exotic phases which spontaneously break the discrete symmetries such as C, P, T as well as CPT. In a regime where the theories are perturbative, the deconfinement temperature in SYM, and QCD(AS/S/BF) coincide. The thermal phase diagrams of thermal orbifold QCD(BF), orientifold QCD(AS/S), and N = 1 SYM coincide, provided charge conjugation symmetry for QCD(AS/S) and Z{sub 2} interchange symmetry of the QCD(BF) are not broken in the phase continuously connected to R{sup 4} limit. When the S{sup 1} circle is endowed with periodic boundary conditions, the (nonthermal) phase diagrams of orbifold and orientifold QCD are still the same, however, both theories possess chirally symmetric phases which are absent in N=1 SYM. The match and mismatch of the phase diagrams depending on the spin structure of fermions along the S{sup 1} circle is naturally explained in terms of the necessary and sufficient symmetry realization conditions which determine the validity of the nonperturbative orbifold orientifold equivalence.

  8. Nonlocal effective gravitational field equations and the running of Newton's constant G

    SciTech Connect

    Hamber, H.W.; Williams, R.M.

    2005-08-15

    Nonperturbative studies of quantum gravity have recently suggested the possibility that the strength of gravitational interactions might slowly increase with distance. Here a set of generally covariant effective field equations are proposed, which are intended to incorporate the gravitational, vacuum-polarization induced, running of Newton's constant G. One attractive feature of this approach is that, from an underlying quantum gravity perspective, the resulting long-distance (or large time) effective gravitational action inherits only one adjustable parameter {xi}, having the units of a length, arising from dimensional transmutation in the gravitational sector. Assuming the above scenario to be correct, some simple predictions for the long-distance corrections to the classical standard model Robertson-Walker metric are worked out in detail, with the results formulated as much as possible in a model-independent framework. It is found that the theory, even in the limit of vanishing renormalized cosmological constant, generally predicts an accelerated power-law expansion at later times t{approx}{xi}{approx}1/H.

  9. Experimental Physics Investigations using Colliding Beam Detectors at Fermilab and the LHC & Nonperturbative Quantum Field Theory: Final Report

    SciTech Connect

    Skubic, P.; Abbott, B.; Gutierrez, P.; Strauss, M.; Kalbfleisch, G.; Kao, C.; Milton, K. A.

    2004-07-01

    Task A: during the past three years, the D collaboration has gone from a period that has concentrated on the analysis of Run I data and the construction of the Run II detector, to the commissioning of the Run II detector and the start of Run II analysis with ≈214 pb₋1 data recorded so far. During the coming years, we expect to collect a factor of 30 to 60 times more data than we did during Run I. This data will be used to test the limits of the standard model (SM), search for new phenomena, and possibly see hints of the Higgs boson. Task B: A major thrust for the past eight years has been based on our experimental project to search for magnetic monopoles produced at Fermilab. Although the experiment has now been concluded, with a nal paper submitted to Physical Review D, theoretically much work remains to be done. A proper interpretation of the experimental results requires improved calculations, both relativistic and nonrelativistic, of the binding of monopoles to atomic nuclei through the anomalous magnetic moment interaction. Improved calculations of the production of monopoles through the Drell-Yan process are also being carried out.

  10. Comparing Running Specific and Traditional Prostheses During Running: Assessing Performance and Risk

    DTIC Science & Technology

    2016-09-01

    AWARD NUMBER: W81XWH-15-1-0518 TITLE: Comparing Running-Specific and Traditional Prostheses during Running: Assessing Performance and Risk...2016 4. TITLE AND SUBTITLE Comparing Running-Specific and Traditional Prostheses During Running: Assessing Performance and Risk 5a. CONTRACT...bbaum@regis.edu 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER Regis

  11. A Runs-Test Algorithm: Contingent Reinforcement and Response Run Structures

    ERIC Educational Resources Information Center

    Hachiga, Yosuke; Sakagami, Takayuki

    2010-01-01

    Four rats' choices between two levers were differentially reinforced using a runs-test algorithm. On each trial, a runs-test score was calculated based on the last 20 choices. In Experiment 1, the onset of stimulus lights cued when the runs score was smaller than criterion. Following cuing, the correct choice was occasionally reinforced with food,…

  12. Development and validation of the European Cluster Assimilation Techniques run libraries

    NASA Astrophysics Data System (ADS)

    Facskó, G.; Gordeev, E.; Palmroth, M.; Honkonen, I.; Janhunen, P.; Sergeev, V.; Kauristie, K.; Milan, S.

    2012-04-01

    The European Commission funded the European Cluster Assimilation Techniques (ECLAT) project as a collaboration of five leader European universities and research institutes. A main contribution of the Finnish Meteorological Institute (FMI) is to provide a wide range global MHD runs with the Grand Unified Magnetosphere Ionosphere Coupling simulation (GUMICS). The runs are divided in two categories: Synthetic runs investigating the extent of solar wind drivers that can influence magnetospheric dynamics, as well as dynamic runs using measured solar wind data as input. Here we consider the first set of runs with synthetic solar wind input. The solar wind density, velocity and the interplanetary magnetic field had different magnitudes and orientations; furthermore two F10.7 flux values were selected for solar radiation minimum and maximum values. The solar wind parameter values were constant such that a constant stable solution was archived. All configurations were run several times with three different (-15°, 0°, +15°) tilt angles in the GSE X-Z plane. The result of the 192 simulations named so called "synthetic run library" were visualized and uploaded to the homepage of the FMI after validation. Here we present details of these runs.

  13. Helix coupling

    DOEpatents

    Ginell, W.S.

    1982-03-17

    A coupling for connecting helix members in series, which consists of a pair of U-shaped elements, one of which is attached to each helix end with the U sections of the elements interlocked. The coupling is particularly beneficial for interconnecting helical Nitinol elements utilized in thermal actuators or engines. Each coupling half is attached to the associated helix at two points, thereby providing axial load while being easily removed from the helix, and reusable.

  14. Helix coupling

    DOEpatents

    Ginell, W.S.

    1989-04-25

    A coupling for connecting helix members in series, which consists of a pair of U-shaped elements, one of which is attached to each helix end with the "U" sections of the elements interlocked. The coupling is particularly beneficial for interconnecting helical Nitinol elements utilized in thermal actuators or engines. Each coupling half is attached to the associated helix at two points, thereby providing axial load while being easily removed from the helix, and reusable.

  15. Helix coupling

    DOEpatents

    Ginell, William S.

    1989-04-25

    A coupling for connecting helix members in series, which consists of a pair of U-shaped elements, one of which is attached to each helix end with the "U" sections of the elements interlocked. The coupling is particularly beneficial for interconnecting helical Nitinol elements utilized in thermal actuators or engines. Each coupling half is attached to the associated helix at two points, thereby providing axial load while being easily removed from the helix, and reusable.

  16. Fatigue-induced changes in decline running.

    PubMed

    Mizrahi, J; Verbitsky, O; Isakov, E

    2001-03-01

    Study the relation between muscle fatigue during eccentric muscle contractions and kinematics of the legs in downhill running. Decline running on a treadmill was used to acquire data on shock accelerations, muscle activity and kinematics, for comparison with level running. In downhill running, local muscle fatigue is the cause of morphological muscle damage which leads to reduced attenuation of shock accelerations. Fourteen subjects ran on a treadmill above level-running anaerobic threshold speed for 30 min, in level and -4 degrees decline running. The following were monitored: metabolic fatigue by means of respiratory parameters; muscle fatigue of the quadriceps by means of elevation in myoelectric activity; and kinematic parameters including knee and ankle angles and hip vertical excursion by means of computerized videography. Data on shock transmission reported in previous studies were also used. Quadriceps fatigue develops in parallel to an increasing vertical excursion of the hip in the stance phase of running, enabled by larger dorsi flexion of the ankle rather than by increased flexion of the knee. The decrease in shock attenuation can be attributed to quadriceps muscle fatigue in parallel to increased vertical excursion of the hips.

  17. Energetics of running: a new perspective.

    PubMed

    Kram, R; Taylor, C R

    1990-07-19

    The amount of energy used to run a mile is nearly the same whether it is run at top speed or at a leisurely pace (although it is used more rapidly at the higher speed). This puzzling independence of energy cost and speed is found generally among running animals, although, on a per gram basis, cost is much higher for smaller animals. Running involves little work against the environment; work is done by muscles and tendons to lift and accelerate the body and limbs. Some of the work is recovered from muscle-tendon springs without metabolic cost and work rate does not parallel metabolic rate with either speed or size. Regardless of the amount of work muscles do, they must be activated and develop force to support the weight of the body. Load-carrying experiments have shown that the cost of supporting an extra newton of load is the same as the weight-specific cost of running. Size differences in cost are proportional to stride frequency at equivalent speeds, suggesting that the time available for developing force is important in determining cost. We report a simple inverse relationship between the rate of energy used for running and the time the foot applies force to the ground during each stride. These results support the hypothesis that it is primarily the cost of supporting the animal's weight and the time course of generating this force that determines the cost of running.

  18. Running Economy from a Muscle Energetics Perspective.

    PubMed

    Fletcher, Jared R; MacIntosh, Brian R

    2017-01-01

    The economy of running has traditionally been quantified from the mass-specific oxygen uptake; however, because fuel substrate usage varies with exercise intensity, it is more accurate to express running economy in units of metabolic energy. Fundamentally, the understanding of the major factors that influence the energy cost of running (Erun) can be obtained with this approach. Erun is determined by the energy needed for skeletal muscle contraction. Here, we approach the study of Erun from that perspective. The amount of energy needed for skeletal muscle contraction is dependent on the force, duration, shortening, shortening velocity, and length of the muscle. These factors therefore dictate the energy cost of running. It is understood that some determinants of the energy cost of running are not trainable: environmental factors, surface characteristics, and certain anthropometric features. Other factors affecting Erun are altered by training: other anthropometric features, muscle and tendon properties, and running mechanics. Here, the key features that dictate the energy cost during distance running are reviewed in the context of skeletal muscle energetics.

  19. Running Economy from a Muscle Energetics Perspective

    PubMed Central

    Fletcher, Jared R.; MacIntosh, Brian R.

    2017-01-01

    The economy of running has traditionally been quantified from the mass-specific oxygen uptake; however, because fuel substrate usage varies with exercise intensity, it is more accurate to express running economy in units of metabolic energy. Fundamentally, the understanding of the major factors that influence the energy cost of running (Erun) can be obtained with this approach. Erun is determined by the energy needed for skeletal muscle contraction. Here, we approach the study of Erun from that perspective. The amount of energy needed for skeletal muscle contraction is dependent on the force, duration, shortening, shortening velocity, and length of the muscle. These factors therefore dictate the energy cost of running. It is understood that some determinants of the energy cost of running are not trainable: environmental factors, surface characteristics, and certain anthropometric features. Other factors affecting Erun are altered by training: other anthropometric features, muscle and tendon properties, and running mechanics. Here, the key features that dictate the energy cost during distance running are reviewed in the context of skeletal muscle energetics. PMID:28690549

  20. Mental Fatigue Impairs Intermittent Running Performance.

    PubMed

    Smith, Mitchell R; Marcora, Samuele M; Coutts, Aaron J

    2015-08-01

    The purpose of the study was to investigate the effects of mental fatigue on intermittent running performance. Ten male intermittent team sports players performed two identical self-paced, intermittent running protocols. The two trials were separated by 7 d and preceded, in a randomized-counterbalanced order, by 90 min of either emotionally neutral documentaries (control) or the AX-continuous performance test (AX-CPT; mental fatigue). Subjective ratings of fatigue and vigor were measured before and after these treatments, and motivation was recorded before the intermittent running protocol. Velocity, heart rate, oxygen consumption, blood glucose and lactate concentrations, and ratings of perceived exertion (RPE) were measured throughout the 45-min intermittent running protocol. Session RPE was recorded 30 min after the intermittent running protocol. Subjective ratings of fatigue were higher after the AX-CPT (P = 0.005). This mental fatigue significantly reduced velocity at low intensities (1.28 ± 0.18 m·s vs 1.31 ± 0.17 m·s; P = 0.037), whereas high-intensity running and peak velocities were not significantly affected. Running velocity at all intensities significantly declined over time in both conditions (P < 0.001). Oxygen consumption was significantly lower in the mental fatigue condition (P = 0.007). Other physiological variables, vigor and motivation, were not significantly affected. Ratings of perceived exertion during the intermittent running protocol were not significantly different between conditions despite lower overall velocity in the mental fatigue condition. Session RPE was significantly higher in the mental fatigue condition (P = 0.013). Mental fatigue impairs intermittent running performance. This negative effect of mental fatigue seems to be mediated by higher perception of effort.

  1. Analysis Of Rearfoot Motion In Running Shoes

    NASA Astrophysics Data System (ADS)

    Cooper, Les

    1986-12-01

    In order to produce better shoes that cushion athletes from the high impact forces of running and still provide stability to the foot it is essential to have a method of quickly and reliably evaluating the performance of prototype shoes. The analysis of rear-foot motion requires the use of film or video recordings of test subjects running on a treadmill. Specific points on the subject are tracked to give a measure of inversion or eversion of the heel. This paper describes the testing procedure and its application to running shoe design. A comparison of film and video systems is also discussed.

  2. Two-dimensional electron gas in the regime of strong light-matter coupling: Dynamical conductivity and all-optical measurements of Rashba and Dresselhaus coupling

    NASA Astrophysics Data System (ADS)

    Yudin, Dmitry; Shelykh, Ivan A.

    2016-10-01

    A nonperturbative interaction of an electronic system with a laser field can substantially modify its physical properties. In particular, in two-dimensional (2D) materials with a lack of inversion symmetry, the achievement of a regime of strong light-matter coupling allows direct optical tuning of the strength of the Rashba spin-orbit interaction (SOI). Capitalizing on these results, we build a theory of the dynamical conductivity of a 2D electron gas with both Rashba and Dresselhaus SOIs coupled to an off-resonant high-frequency electromagnetic wave. We argue that strong light-matter coupling modifies qualitatively the dispersion of the electrons and can be used as a powerful tool to probe and manipulate the coupling strengths and adjust the frequency range where optical conductivity is essentially nonzero.

  3. No influence of ischemic preconditioning on running economy.

    PubMed

    Kaur, Gungeet; Binger, Megan; Evans, Claire; Trachte, Tiffany; Van Guilder, Gary P

    2017-02-01

    Many of the potential performance-enhancing properties of ischemic preconditioning suggest that the oxygen cost for a given endurance exercise workload will be reduced, thereby improving the economy of locomotion. The aim of this study was to identify whether ischemic preconditioning improves exercise economy in recreational runners. A randomized sham-controlled crossover study was employed in which 18 adults (age 27 ± 7 years; BMI 24.6 ± 3 kg/m(2)) completed two, incremental submaximal (65-85% VO2max) treadmill running protocols (3 × 5 min stages from 7.2-14.5 km/h) coupled with indirect calorimetry to assess running economy following ischemic preconditioning (3 × 5 min bilateral upper thigh ischemia) and sham control. Running economy was expressed as mlO2/kg/km and as the energy in kilocalories required to cover 1 km of horizontal distance (kcal/kg/km). Ischemic preconditioning did not influence steady-state heart rate, oxygen consumption, minute ventilation, respiratory exchange ratio, energy expenditure, and blood lactate. Likewise, running economy was similar (P = 0.647) between the sham (from 201.6 ± 17.7 to 204.0 ± 16.1 mlO2/kg/km) and ischemic preconditioning trials (from 202.8 ± 16.2 to 203.1 ± 15.6 mlO2/kg/km). There was no influence (P = 0.21) of ischemic preconditioning on running economy expressed as the caloric unit cost (from 0.96 ± 0.12 to 1.01 ± 0.11 kcal/kg/km) compared with sham (from 1.00 ± 0.10 to 1.00 ± 0.08 kcal/kg/km). The properties of ischemic preconditioning thought to affect exercise performance at vigorous to severe exercise intensities, which generate more extensive physiological challenge, are ineffective at submaximal workloads and, therefore, do not change running economy.

  4. Smarter running can keep buildings fit.

    PubMed

    England, Simon

    2011-09-01

    Simon England, director at Accenture Health UK, outlines the benefits of an "assessment-based" approach to creating "smarter" healthcare buildings with reduced running costs and a lower carbon footprint.

  5. Gravitational baryogenesis in running vacuum models

    NASA Astrophysics Data System (ADS)

    Oikonomou, V. K.; Pan, Supriya; Nunes, Rafael C.

    2017-08-01

    We study the gravitational baryogenesis mechanism for generating baryon asymmetry in the context of running vacuum models. Regardless of whether these models can produce a viable cosmological evolution, we demonstrate that they produce a nonzero baryon-to-entropy ratio even if the universe is filled with conformal matter. This is a sound difference between the running vacuum gravitational baryogenesis and the Einstein-Hilbert one, since in the latter case, the predicted baryon-to-entropy ratio is zero. We consider two well known and most used running vacuum models and show that the resulting baryon-to-entropy ratio is compatible with the observational data. Moreover, we also show that the mechanism of gravitational baryogenesis may constrain the running vacuum models.

  6. [Experiences with running therapy in essential hypertension].

    PubMed

    Winterfeld, H J; Siewert, H; Strangfeld, D

    1995-03-21

    The authors report about a long-term study (three months) on blood pressure and heart rate at rest and during exercise (50 W) in hypertensive patients (WHO stadium I and I, n = 24) running twice a week. The control group were 15 healthy people who were running as well. In addition, the peripheral microcirculation (musculus tibialis anterior) was recorded by the Xenon-133 muscle clearance method and the cardiac output by means of radiocardiography (Indium 113m) as parameter of central hemodynamics. A positive influence of running on hypertension and hemodynamics, resulting in a significant decrease of systolic and diastolic blood pressure and a significant improvement of the peripheral microcirculation was registered. The measured values of blood pressure, heart rate and cardiac output show that there was no cardial risk caused by running at a velocity of 2 to 2.5 m/s.

  7. Social network structures and bank runs

    NASA Astrophysics Data System (ADS)

    Li, Shouwei; Li, Jiaheng

    2016-05-01

    This paper investigates the impact of social network structures of depositors on bank runs. The analyzed network structures include random networks, small-world networks and scale-free networks. Simulation results show that the probability of bank run occurrence in random networks is larger than that in small-world networks, but the probability of bank run occurrence in scale-free networks drops from the highest to the lowest among the three types of network structures with the increase of the proportion of impatient depositors. The average degree of depositor networks has a significant impact on bank runs, but this impact is related to the proportion of impatient depositors and the confidence levels of depositors in banks.

  8. The calculation of take-off run

    NASA Technical Reports Server (NTRS)

    Diehl, Walter S

    1934-01-01

    A comparatively simple method of calculating length of take-off run is developed from the assumption of a linear variation in net accelerating force with air speed and it is shown that the error involved is negligible.

  9. Flood-plain delineation for Horsepen Run, Sugarland Run, Nichols Run, Pond Branch, Clarks Branch, and Mine Run Branch basins, Fairfax County, Virginia

    USGS Publications Warehouse

    Soule, Pat LeRoy

    1978-01-01

    Water-surface profiles of the 25-, 50-, and 100-year recurrence interval discharges have been computed for all streams and reaches of channels in Fairfax County, Virginia, having a drainage area greater than 1 square mile except for Dogue Creek, Little Hunting Creek, and that portion of Cameron Run above Lake Barcroft. Maps have a 2-foot contour interval and a horizontal scale of 1 inch equals 100 feet were used for base on which flood boundaries were delineated for 25-, 50-, and 100-year floods to be expected in each basin under ultimate development conditions. This report is one of a series and presents a discussion of techniques employed in computing discharges and profiles as well as the flood profiles and maps on which flood boundaries have been delineated for the Horsepen Run, Sugarland Run, Nichols Run, and Pond Branch basins in Fairfax County. (Woodard-USGS)

  10. The meaning of running away for girls.

    PubMed

    Peled, Einat; Cohavi, Ayelet

    2009-10-01

    The aim of this qualitative research was to understand how runaway girls perceive the processes involved in leaving home and the meaning they attribute to it. Findings are based on in-depth interviews with 10 Israeli girls aged 13-17 with a history of running away from home. The meaning of running away as it emerged from the girls' descriptions of their lives prior to leaving home was that of survival - both psychological and physical. The girls' stories centered on their evolving experiences of alienation, loneliness and detachment, and the failure of significant relationships at home and outside of home to provide them with the support they needed. These experiences laid the ground for the "final moments" before leaving, when a feeling of "no alternative," a hope for a better future, and various particular triggers led the girls to the decision to leave home. Participants' insights about the dynamics leading to running-away center on the meaning of family relationships, particularly those with the mother, as constituting the girl's psychological home. The girls seemed to perceive running away as an inevitability, rather than a choice, and even portrayed the running away as "living suicide." Yet, their stories clearly demonstrate their ability to cope and the possession of strengths and skills that enabled them to survive in extremely difficult home situations. The findings of this research highlight the importance of improving services for reaching out and supporting girls who are on the verge of running away from home. Such services should be tailored to the needs of girls who experience extreme but often silenced distress at home, and should facilitate alternative solutions to the girls' plight other than running away. An understanding of the dynamics leading to running away from the girls' perspective has the potential to improve the efficacy of services provided by contributing to the creation of a caring, empowering, understanding and trustful professional

  11. Minimum-time running: a numerical approach.

    PubMed

    Maroński, Ryszard; Rogowski, Krzysztof

    2011-01-01

    The article deals with the minimum-time running problem. The time of covering a given distance is minimized. The Hill-Keller model of running employed is based on Newton's second law and the equation of power balance. The problem is formulated in optimal control. The unknown function is the runner's velocity that varies with the distance. The problem is solved applying the direct Chebyshev's pseudospectral method.

  12. CDF forward shielding for Run II

    SciTech Connect

    Krivosheev, O.E.; Mokhov, N.V.

    1998-03-16

    Detailed calculations of the accelerator related background in the CDF forward muon spectrometer have been performed with the MARS13 code and a newly developed C++ code for particle tracking in accelerator lattices. Calculated space distributions of background hits are in a good agreement with data taken in Run I. Several shielding configurations in the CDF hall and Tevatron tunnel have been studied. The optimal one provides a 30-fold shielding efficiency compatible with CDF Run II requirements.

  13. The Ssart of Run II at CDF

    SciTech Connect

    Marco Rescigno

    2002-10-29

    After a hiatus of almost 6 years and an extensive upgrade, Tevatron, the world largest proton-antiproton collider, has resumed the operation for the so called RUN II. In this paper we give a brief overview of the many new features of the Tevatron complex and of the upgraded CDF experiment, and show the presently achieved detector performances as well as highlights of the RUN II physics program in the beauty and electroweak sector.

  14. RHIC Polarized proton performance in run-8

    SciTech Connect

    Montag,C.; Bai, M.; MacKay, W.W.; Roser, T.; Abreu, N.; Ahrens, L.; Barton, D.; Beebe-Wang, J.; Blaskiewicz, M.; Brennan, J.M.; Brown, K.A.; Bruno, D.; Bunce, G.; Calaga, R.; Cameron, P.; Connolly, R.; D'Ottavio, T.; Drees, A.; Fedotov, A.V.; Fischer, W.; Ganetis, G.; Gardner, C.; Glenn, J.; Hayes, T.; Huang, H.; Ingrassia, P.; Kayran, D.A.; Kewisch, J.; Lee, R.C.; Lin, F.; Litvinenko, V.N.; Luccio, A.U.; Luo, Y.; Makdisi, Y.; Malitsky, N.; Marr, G.; Marusic, A.; Michnoff, R.; Morris, J.; Oerter, B.; Pilat, F.; Pile, P.; Robert-Demolaize, G.; Russo, T.; Satogata, T.; Schultheiss, C.; Sivertz, M.; Smith, K.; Tepikian, S.; D. Trbojevic, D.; Tsoupas, N.; Tuozzolo, J.; Zaltsman, A.; Zelenski, A.; Zeno, K.; Zhang, S.Y.

    2008-10-06

    During Run-8, the Relativistic Heavy Ion Collider (RHIC) provided collisions of spin-polarized proton beams at two interaction regions. Physics data were taken with vertical orientation of the beam polarization, which in the 'Yellow' RHIC ring was significantly lower than in previous years. We present recent developments and improvements as well as the luminosity and polarization performance achieved during Run-8, and we discuss possible causes of the not as high as previously achieved polarization performance of the 'Yellow' ring.

  15. RHIC polarized proton performance in run-8.

    SciTech Connect

    Montag,C.; Abreu, N.; Ahrens, L.; Bai, M.; Barton, D.; et al.

    2008-06-23

    During Run-8, the Relativistic Heavy Ion Collider (RHIC) provided collisions of spin-polarized proton beams at two interaction regions. Helical spin rotators at these two interaction regions were used to control the spin orientation of both beams at the collision points. Physics data were taken with different orientations of the beam polarization. We present recent developments and improvements as well as the luminosity and polarization performance achieved during Run-8.

  16. Nonperturbative-transverse-momentum effects and evolution in dihadron and direct photon-hadron angular correlations in p +p collisions at √{s } =510 GeV

    NASA Astrophysics Data System (ADS)

    Adare, A.; Aidala, C.; Ajitanand, N. N.; Akiba, Y.; Akimoto, R.; Alexander, J.; Alfred, M.; Andrieux, V.; Aoki, K.; Apadula, N.; Aramaki, Y.; Asano, H.; Atomssa, E. T.; Awes, T. C.; Ayuso, C.; Azmoun, B.; Babintsev, V.; Bai, M.; Bai, X.; Bandara, N. S.; Bannier, B.; Barish, K. N.; Bathe, S.; Baublis, V.; Baumann, C.; Baumgart, S.; Bazilevsky, A.; Beaumier, M.; Beckman, S.; Belmont, R.; Berdnikov, A.; Berdnikov, Y.; Black, D.; Blau, D. S.; Boer, M.; Bok, J. S.; Boyle, K.; Brooks, M. L.; Bryslawskyj, J.; Buesching, H.; Bumazhnov, V.; Butler, C.; Butsyk, S.; Campbell, S.; Canoa Roman, V.; Cervantes, R.; Chen, C.-H.; Chi, C. Y.; Chiu, M.; Choi, I. J.; Choi, J. B.; Choi, S.; Christiansen, P.; Chujo, T.; Cianciolo, V.; Citron, Z.; Cole, B. A.; Connors, M.; Cronin, N.; Crossette, N.; Csanád, M.; Csörgő, T.; Danley, T. W.; Datta, A.; Daugherity, M. S.; David, G.; Deblasio, K.; Dehmelt, K.; Denisov, A.; Deshpande, A.; Desmond, E. J.; Ding, L.; Dion, A.; Dixit, D.; Do, J. H.; D'Orazio, L.; Drapier, O.; Drees, A.; Drees, K. A.; Dumancic, M.; Durham, J. M.; Durum, A.; Elder, T.; Engelmore, T.; Enokizono, A.; En'yo, H.; Esumi, S.; Eyser, K. O.; Fadem, B.; Fan, W.; Feege, N.; Fields, D. E.; Finger, M.; Finger, M.; Fleuret, F.; Fokin, S. L.; Frantz, J. E.; Franz, A.; Frawley, A. D.; Fukao, Y.; Fukuda, Y.; Fusayasu, T.; Gainey, K.; Gal, C.; Gallus, P.; Garg, P.; Garishvili, A.; Garishvili, I.; Ge, H.; Giordano, F.; Glenn, A.; Gong, X.; Gonin, M.; Goto, Y.; Granier de Cassagnac, R.; Grau, N.; Greene, S. V.; Grosse Perdekamp, M.; Gu, Y.; Gunji, T.; Guragain, H.; Hachiya, T.; Haggerty, J. S.; Hahn, K. I.; Hamagaki, H.; Hamilton, H. F.; Han, S. Y.; Hanks, J.; Hasegawa, S.; Haseler, T. O. S.; Hashimoto, K.; Hayano, R.; He, X.; Hemmick, T. K.; Hester, T.; Hill, J. C.; Hill, K.; Hollis, R. S.; Homma, K.; Hong, B.; Hoshino, T.; Hotvedt, N.; Huang, J.; Huang, S.; Ichihara, T.; Ikeda, Y.; Imai, K.; Imazu, Y.; Imrek, J.; Inaba, M.; Iordanova, A.; Isenhower, D.; Isinhue, A.; Ito, Y.; Ivanishchev, D.; Jacak, B. V.; Jeon, S. J.; Jezghani, M.; Ji, Z.; Jia, J.; Jiang, X.; Johnson, B. M.; Joo, E.; Joo, K. S.; Jorjadze, V.; Jouan, D.; Jumper, D. S.; Kamin, J.; Kanda, S.; Kang, B. H.; Kang, J. H.; Kang, J. S.; Kapukchyan, D.; Kapustinsky, J.; Karthas, S.; Kawall, D.; Kazantsev, A. V.; Key, J. A.; Khachatryan, V.; Khandai, P. K.; Khanzadeev, A.; Kihara, K.; Kijima, K. M.; Kim, C.; Kim, D. H.; Kim, D. J.; Kim, E.-J.; Kim, H.-J.; Kim, M. H.; Kim, M.; Kim, Y.-J.; Kim, Y. K.; Kincses, D.; Kistenev, E.; Klatsky, J.; Kleinjan, D.; Kline, P.; Koblesky, T.; Kofarago, M.; Komkov, B.; Koster, J.; Kotchetkov, D.; Kotov, D.; Krizek, F.; Kudo, S.; Kurita, K.; Kurosawa, M.; Kwon, Y.; Lacey, R.; Lai, Y. S.; Lajoie, J. G.; Lallow, E. O.; Lebedev, A.; Lee, D. M.; Lee, G. H.; Lee, J.; Lee, K. B.; Lee, K. S.; Lee, S.; Lee, S. H.; Leitch, M. J.; Leitgab, M.; Leung, Y. H.; Lewis, B.; Lewis, N. A.; Li, X.; Li, X.; Lim, S. H.; Liu, L. D.; Liu, M. X.; Loggins, V.-R.; Loggins, V.-R.; Lovasz, K.; Lynch, D.; Maguire, C. F.; Majoros, T.; Makdisi, Y. I.; Makek, M.; Malaev, M.; Manion, A.; Manko, V. I.; Mannel, E.; Masuda, H.; McCumber, M.; McGaughey, P. L.; McGlinchey, D.; McKinney, C.; Meles, A.; Mendoza, M.; Meredith, B.; Miake, Y.; Mibe, T.; Mignerey, A. C.; Mihalik, D. E.; Miller, A. J.; Milov, A.; Mishra, D. K.; Mitchell, J. T.; Mitsuka, G.; Miyasaka, S.; Mizuno, S.; Mohanty, A. K.; Mohapatra, S.; Montuenga, P.; Moon, T.; Morrison, D. P.; Morrow, S. I. M.; Moskowitz, M.; Moukhanova, T. V.; Murakami, T.; Murata, J.; Mwai, A.; Nagae, T.; Nagai, K.; Nagamiya, S.; Nagashima, K.; Nagashima, T.; Nagle, J. L.; Nagy, M. I.; Nakagawa, I.; Nakagomi, H.; Nakamiya, Y.; Nakamura, K. R.; Nakamura, T.; Nakano, K.; Nattrass, C.; Netrakanti, P. K.; Nihashi, M.; Niida, T.; Nouicer, R.; Novák, T.; Novitzky, N.; Novotny, R.; Nyanin, A. S.; O'Brien, E.; Ogilvie, C. A.; Oide, H.; Okada, K.; Orjuela Koop, J. D.; Osborn, J. D.; Oskarsson, A.; Ottino, G. J.; Ozawa, K.; Pak, R.; Pantuev, V.; Papavassiliou, V.; Park, I. H.; Park, J. S.; Park, S.; Park, S. K.; Pate, S. F.; Patel, L.; Patel, M.; Peng, J.-C.; Peng, W.; Perepelitsa, D. V.; Perera, G. D. N.; Peressounko, D. Yu.; Perezlara, C. E.; Perry, J.; Petti, R.; Phipps, M.; Pinkenburg, C.; Pinson, R.; Pisani, R. P.; Pun, A.; Purschke, M. L.; Qu, H.; Rak, J.; Ravinovich, I.; Read, K. F.; Reynolds, D.; Riabov, V.; Riabov, Y.; Richardson, E.; Richford, D.; Rinn, T.; Riveli, N.; Roach, D.; Rolnick, S. D.; Rosati, M.; Rowan, Z.; Rubin, J. G.; Runchey, J.; Ryu, M. S.; Safonov, A. S.; Sahlmueller, B.; Saito, N.; Sakaguchi, T.; Sako, H.; Samsonov, V.; Sarsour, M.; Sato, K.; Sato, S.; Sawada, S.; Schaefer, B.; Schmoll, B. K.; Schmoll, B. K.; Sedgwick, K.; Seele, J.; Seidl, R.; Sekiguchi, Y.; Sen, A.; Seto, R.; Sett, P.; Sexton, A.; Sharma, D.; Shaver, A.; Shein, I.; Shibata, T.-A.; Shigaki, K.; Shimomura, M.; Shioya, T.; Shoji, K.; Shukla, P.; Sickles, A.; Silva, C. L.; Silvermyr, D.; Singh, B. K.; Singh, C. P.; Singh, V.; Skolnik, M.; Slunečka, M.; Smith, K. L.; Snowball, M.; Solano, S.; Soltz, R. A.; Sondheim, W. E.; Sorensen, S. P.; Sourikova, I. V.; Stankus, P. W.; Steinberg, P.; Stenlund, E.; Stepanov, M.; Ster, A.; Stoll, S. P.; Stone, M. R.; Sugitate, T.; Sukhanov, A.; Sumita, T.; Sun, J.; Syed, S.; Sziklai, J.; Takahara, A.; Takeda, A.; Taketani, A.; Tanaka, Y.; Tanida, K.; Tannenbaum, M. J.; Tarafdar, S.; Taranenko, A.; Tarnai, G.; Tennant, E.; Tieulent, R.; Timilsina, A.; Todoroki, T.; Tomášek, M.; Torii, H.; Towell, C. L.; Towell, M.; Towell, R.; Towell, R. S.; Tserruya, I.; Ueda, Y.; Ujvari, B.; van Hecke, H. W.; Vargyas, M.; Vazquez-Carson, S.; Vazquez-Zambrano, E.; Veicht, A.; Velkovska, J.; Vértesi, R.; Virius, M.; Vrba, V.; Vukman, N.; Vznuzdaev, E.; Wang, X. R.; Wang, Z.; Watanabe, D.; Watanabe, K.; Watanabe, Y.; Watanabe, Y. S.; Wei, F.; Whitaker, S.; Wolin, S.; Wong, C. P.; Woody, C. L.; Wysocki, M.; Xia, B.; Xu, C.; Xu, Q.; Xue, L.; Yalcin, S.; Yamaguchi, Y. L.; Yamamoto, H.; Yanovich, A.; Yin, P.; Yokkaichi, S.; Yoo, J. H.; Yoon, I.; You, Z.; Younus, I.; Yu, H.; Yushmanov, I. E.; Zajc, W. A.; Zelenski, A.; Zharko, S.; Zhou, S.; Zou, L.; Phenix Collaboration

    2017-04-01

    Dihadron and isolated direct photon-hadron angular correlations are measured in p +p collisions at √{s }=510 GeV . Correlations of charged hadrons of 0.7 nonperturbative effects generated by initial-state partonic transverse momentum and final-state transverse momentum from fragmentation. The nonperturbative behavior is characterized by measuring the out-of-plane transverse momentum component pout perpendicular to the axis of the trigger particle, which is the high-pT direct photon or π0. Nonperturbative evolution effects are extracted from Gaussian fits to the away-side inclusive-charged-hadron yields for different trigger-particle transverse momenta (pTtrig ). The Gaussian widths and root mean square of pout are reported as a function of the interaction hard scale pTtrig to investigate possible transverse-momentum-dependent evolution differences between the π0-h± and direct photon-h± correlations and factorization breaking effects. The widths are found to decrease with pTtrig , which indicates that the Collins-Soper-Sterman soft factor is not driving the evolution with the hard scale in nearly back-to-back dihadron and direct photon-hadron production in p +p collisions. This behavior is in contrast to Drell-Yan and semi-inclusive deep-inelastic scattering measurements.

  17. Negative running can prevent eternal inflation

    NASA Astrophysics Data System (ADS)

    Kinney, William H.; Freese, Katherine

    2015-01-01

    Current data from the Planck satellite and the BICEP2 telescope favor, at around the 2 σ level, negative running of the spectral index of curvature perturbations from inflation. We show that for negative running α < 0, the curvature perturbation amplitude has a maximum on scales larger than our current horizon size. A condition for the absence of eternal inflation is that the curvature perturbation amplitude always remain below unity on superhorizon scales. For current bounds on nS from Planck, this corresponds to an upper bound of the running α < -9 × 10-5, so that even tiny running of the scalar spectral index is sufficient to prevent eternal inflation from occurring, as long as the running remains negative on scales outside the horizon. In single-field inflation models, negative running is associated with a finite duration of inflation: we show that eternal inflation may not occur even in cases where inflation lasts as long as 104 e-folds.

  18. Metadata aided run selection at ATLAS

    NASA Astrophysics Data System (ADS)

    Buckingham, R. M.; Gallas, E. J.; C-L Tseng, J.; Viegas, F.; Vinek, E.; ATLAS Collaboration

    2011-12-01

    Management of the large volume of data collected by any large scale scientific experiment requires the collection of coherent metadata quantities, which can be used by reconstruction or analysis programs and/or user interfaces, to pinpoint collections of data needed for specific purposes. In the ATLAS experiment at the LHC, we have collected metadata from systems storing non-event-wise data (Conditions) into a relational database. The Conditions metadata (COMA) database tables not only contain conditions known at the time of event recording, but also allow for the addition of conditions data collected as a result of later analysis of the data (such as improved measurements of beam conditions or assessments of data quality). A new web based interface called "runBrowser" makes these Conditions Metadata available as a Run based selection service. runBrowser, based on PHP and JavaScript, uses jQuery to present selection criteria and report results. It not only facilitates data selection by conditions attributes, but also gives the user information at each stage about the relationship between the conditions chosen and the remaining conditions criteria available. When a set of COMA selections are complete, runBrowser produces a human readable report as well as an XML file in a standardized ATLAS format. This XML can be saved for later use or refinement in a future runBrowser session, shared with physics/detector groups, or used as input to ELSSI (event level Metadata browser) or other ATLAS run or event processing services.

  19. Running With an Elastic Lower Limb Exoskeleton.

    PubMed

    Cherry, Michael S; Kota, Sridhar; Young, Aaron; Ferris, Daniel P

    2016-06-01

    Although there have been many lower limb robotic exoskeletons that have been tested for human walking, few devices have been tested for assisting running. It is possible that a pseudo-passive elastic exoskeleton could benefit human running without the addition of electrical motors due to the spring-like behavior of the human leg. We developed an elastic lower limb exoskeleton that added stiffness in parallel with the entire lower limb. Six healthy, young subjects ran on a treadmill at 2.3 m/s with and without the exoskeleton. Although the exoskeleton was designed to provide ~50% of normal leg stiffness during running, it only provided 24% of leg stiffness during testing. The difference in added leg stiffness was primarily due to soft tissue compression and harness compliance decreasing exoskeleton displacement during stance. As a result, the exoskeleton only supported about 7% of the peak vertical ground reaction force. There was a significant increase in metabolic cost when running with the exoskeleton compared with running without the exoskeleton (ANOVA, P < .01). We conclude that 2 major roadblocks to designing successful lower limb robotic exoskeletons for human running are human-machine interface compliance and the extra lower limb inertia from the exoskeleton.

  20. Negative running can prevent eternal inflation

    SciTech Connect

    Kinney, William H.; Freese, Katherine E-mail: ktfreese@umich.edu

    2015-01-01

    Current data from the Planck satellite and the BICEP2 telescope favor, at around the 2 σ level, negative running of the spectral index of curvature perturbations from inflation. We show that for negative running α < 0, the curvature perturbation amplitude has a maximum on scales larger than our current horizon size. A condition for the absence of eternal inflation is that the curvature perturbation amplitude always remain below unity on superhorizon scales. For current bounds on n{sub S} from Planck, this corresponds to an upper bound of the running α < −9 × 10{sup −5}, so that even tiny running of the scalar spectral index is sufficient to prevent eternal inflation from occurring, as long as the running remains negative on scales outside the horizon. In single-field inflation models, negative running is associated with a finite duration of inflation: we show that eternal inflation may not occur even in cases where inflation lasts as long as 10{sup 4} e-folds.