Kaon semileptonic decay form factors from Nf = 2 non-perturbatively O(a)-improved Wilson fermions
International Nuclear Information System (INIS)
Broemmel, D.; Nakamura, Y.; Pleiter, D.
2007-10-01
We present first results from the QCDSF collaboration for the kaon semileptonic decay form factors at zero momentum transfer, using two flavours of non-perturbatively O(a)-improved Wilson quarks. A lattice determination of these form factors is of particular interest to improve the accuracy on the CKM matrix element vertical stroke V us vertical stroke. Calculations are performed on lattices with lattice spacing of about 0.08 fm with different values of light and strange quark masses, which allows us to extrapolate to chiral limit. Employing double ratio techniques, we are able to get small statistical errors. (orig.)
Simulation of QCD with N_f=2+1 flavors of non-perturbatively improved Wilson fermions
International Nuclear Information System (INIS)
Bruno, Mattia; Djukanovic, Dalibor; Engel, Georg P.; Francis, Anthony; Herdoiza, Gregorio; Horch, Hanno; Korcyl, Piotr; Korzec, Tomasz; Papinutto, Mauro; Schaefer, Stefan; Scholz, Enno E.; Simeth, Jakob; Simma, Hubert; Söldner, Wolfgang
2015-01-01
We describe a new set of gauge configurations generated within the CLS effort. These ensembles have N_f=2+1 flavors of non-perturbatively improved Wilson fermions in the sea with the Lüscher-Weisz action used for the gluons. Open boundary conditions in time are used to address the problem of topological freezing at small lattice spacings and twisted-mass reweighting for improved stability of the simulations. We give the bare parameters at which the ensembles have been generated and how these parameters have been chosen. Details of the algorithmic setup and its performance are presented as well as measurements of the pion and kaon masses alongside the scale parameter t_0.
International Nuclear Information System (INIS)
Kaneko, T.; Hashimoto, S.; Aoki, S.; Hoffmann, R.
2007-03-01
We perform a non-perturbative determination of the improvement coefficient c A to remove O(a) discretization errors in the axial vector current in three-flavor lattice QCD with the Iwasaki gauge action and the standard O(a)-improved Wilson quark action. An improvement condition with a good sensitivity to c A is imposed at constant physics. Combining our results with the perturbative expansion, c A is now known rather precisely for a -1 >or similar 1.6 GeV. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Kaneko, T.; Hashimoto, S. [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki (Japan)]|[Graduate Univ. for Advanced Studies, Tsukuba, Ibaraki (Japan); Aoki, S. [Tsukuba Univ., Ibaraki (Japan). Graduate School of Pure and Applied Sciences]|[Brookhaven National Laboratory, Upton, NY (United States). Riken BNL Research Center; Della Morte, M. [CERN, Physics Dept., Geneva (Switzerland); Hoffmann, R. [Colorado Univ., Boulder, CO (United States). Dept. of Physics; Sommer, R. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)
2007-03-15
We perform a non-perturbative determination of the improvement coefficient c{sub A} to remove O(a) discretization errors in the axial vector current in three-flavor lattice QCD with the Iwasaki gauge action and the standard O(a)-improved Wilson quark action. An improvement condition with a good sensitivity to c{sub A} is imposed at constant physics. Combining our results with the perturbative expansion, c{sub A} is now known rather precisely for a{sup -1}>or similar 1.6 GeV. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Palombi, F.
2007-06-15
We carry out the renormalization and the Symanzik O(a)-improvement programme for the static vector current in quenched lattice QCD. The scale independent ratio of the renormalization constants of the static vector and axial currents is obtained non-perturbatively from an axial Ward identity with Wilson-type light quarks and various lattice discretizations of the static action. The improvement coefficients c{sub V}{sup stat} and b{sub V}{sup stat} are obtained up to O(g{sub 4}{sup 0})-terms by enforcing improvement conditions respectively on the axial Ward identity and a three-point correlator of the static vector current. A comparison between the non-perturbative estimates and the corresponding one-loop results shows a non-negligible effect of the O(g{sub 4}{sup 0})-terms on the improvement coefficients but a good accuracy of the perturbative description of the ratio of the renormalization constants. (orig.)
Zero point energy of renormalized Wilson loops
International Nuclear Information System (INIS)
Hidaka, Yoshimasa; Pisarski, Robert D.
2009-01-01
The quark-antiquark potential, and its associated zero point energy, can be extracted from lattice measurements of the Wilson loop. We discuss a unique prescription to renormalize the Wilson loop, for which the perturbative contribution to the zero point energy vanishes identically. A zero point energy can arise nonperturbatively, which we illustrate by considering effective string models. The nonperturbative contribution to the zero point energy vanishes in the Nambu model, but is nonzero when terms for extrinsic curvature are included. At one loop order, the nonperturbative contribution to the zero point energy is negative, regardless of the sign of the extrinsic curvature term.
A non-perturbative operator product expansion
International Nuclear Information System (INIS)
Bietenholz, W.; Cundy, N.; Goeckeler, M.
2009-10-01
Nucleon structure functions can be observed in Deep Inelastic Scattering experiments, but it is an outstanding challenge to confront them with fully non-perturbative QCD results. For this purpose we investigate the product of electromagnetic currents (with large photonmomenta) between quark states (of low momenta). By means of an Operator Product Expansion the structure function can be decomposed into matrix elements of local operators, and Wilson coefficients. For consistency both have to be computed non-perturbatively. Here we present precision results for a set of Wilson coefficients. They are evaluated from propagators for numerous quark momenta on the lattice, where the use of chiral fermions suppresses undesired operator mixing. This overdetermines the Wilson coefficients, but reliable results can be extracted by means of a Singular Value Decomposition. (orig.)
Zero Point Energy of Renormalized Wilson Loops
Hidaka, Yoshimasa; Pisarski, Robert D.
2009-01-01
The quark antiquark potential, and its associated zero point energy, can be extracted from lattice measurements of the Wilson loop. We discuss a unique prescription to renormalize the Wilson loop, for which the perturbative contribution to the zero point energy vanishes identically. A zero point energy can arise nonperturbatively, which we illustrate by considering effective string models. The nonperturbative contribution to the zero point energy vanishes in the Nambu model, but is nonzero wh...
The non-perturbative QCD Debye mass from a Wilson line operator
Laine, Mikko
1999-01-01
According to a proposal by Arnold and Yaffe, the non-perturbative g^2T-contribution to the Debye mass in the deconfined QCD plasma phase can be determined from a single Wilson line operator in the three-dimensional pure SU(3) gauge theory. We extend a previous SU(2) measurement of this quantity to the physical SU(3) case. We find a numerical coefficient which is more accurate and smaller than that obtained previously with another method, but still very large compared with the naive expectation: the correction is larger than the leading term up to T ~ 10^7 T_c, corresponding to g^2 ~ 0.4. At moderate temperatures T ~ 2 T_c, a consistent picture emerges where the Debye mass is m_D ~ 6T, the lightest gauge invariant screening mass in the system is ~ 3T, and the purely magnetic operators couple dominantly to a scale ~ 6T. Electric (~ gT) and magnetic (~ g^2T) scales are therefore strongly overlapping close to the phase transition, and the colour-electric fields play an essential role in the dynamics.
Symanzik Improvement with Dynamical Charm: A 3+1 Scheme for Wilson Quarks arXiv
Fritzsch, Patrick; Stollenwerk, Felix; Wolff, Ulli
We discuss the problem of lattice artefacts in QCD simulations enhanced by the introduction of dynamical charmed quarks. In particular, we advocate the use of a massive renormalization scheme with a close to realistic charm mass. To maintain O(a) improvement for Wilson type fermions in this case we define a finite size scheme and carry out a nonperturbative estimation of the clover coefficient $c_\\mathrm{sw}$. It is summarized in a fit formula $c_\\mathrm{sw}(g_0^2)$ that defines an improved action suitable for future dynamical charm simulations.
M{sub b} and f{sub B} from non-perturbatively renormalized HQET with N{sub f} = 2 light quarks
Energy Technology Data Exchange (ETDEWEB)
Blossier, Benoit [CNRS et Univ. Paris-Sud XI, Orsay (France). Lab. de Physique Theorique; Bulava, John [CERN, Geneva (Switzerland). Physics Dept.; Della Morte, Michele; Hippel, Georg von [Mainz Univ. (Germany). Inst. fuer Kernphysik; Donnellan, Michael; Simma, Hubert; Sommer, Rainer [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). NIC; Fritzsch, Patrick [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Garron, Nicolas [Edinburgh Univ. (United Kingdom). Tait Inst.; Heitger, Jochen [Muenster Univ. (Germany). Inst. fuer Theoretische Physik 1
2011-12-15
We present an updated analysis of the non-perturbatively renormalized b-quark mass and B meson decay constant based on CLS lattices with two dynamical non-perturbatively improved Wilson quarks. This update incorporates additional light quark masses and lattice spacings in large physical volume to improve chiral extrapolations and to reach the continuum limit. We use Heavy Quark Effective Theory (HQET) including 1/m{sub b} terms with non-perturbative coefficients based on the matching of QCD and HQET developed by the ALPHA collaboration during the past years. (orig.)
Non-perturbative renormalization of static-light four-fermion operators in quenched lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Palombi, F. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Papinutto, M.; Pena, C. [CERN, Geneva (Switzerland). Physics Dept., Theory Div.; Wittig, H. [Mainz Univ. (Germany). Inst. fuer Kernphysik
2007-06-15
We perform a non-perturbative study of the scale-dependent renormalization factors of a multiplicatively renormalizable basis of {delta}B=2 parity-odd four-fermion operators in quenched lattice QCD. Heavy quarks are treated in the static approximation with various lattice discretizations of the static action. Light quarks are described by nonperturbatively O(a) improved Wilson-type fermions. The renormalization group running is computed for a family of Schroedinger functional (SF) schemes through finite volume techniques in the continuum limit. We compute non-perturbatively the relation between the renormalization group invariant operators and their counterparts renormalized in the SF at a low energy scale. Furthermore, we provide non-perturbative estimates for the matching between the lattice regularized theory and all the SF schemes considered. (orig.)
Chirally improving Wilson fermions I. O(a) improvement
International Nuclear Information System (INIS)
Frezzotti, R.; Rossi, G.C.
2004-01-01
We show that it is possible to improve the chiral behaviour and the approach to the continuum limit of correlation functions in lattice QCD with Wilson fermions by taking arithmetic averages of correlators computed in theories regularized with Wilson terms of opposite sign. Improved hadronic masses and matrix elements can be obtained by similarly averaging the corresponding physical quantities separately computed within the two regularizations. To deal with the problems related to the spectrum of the Wilson-Dirac operator, which are particularly worrisome when Wilson and mass terms are such as to give contributions of opposite sign to the real part of the eigenvalues, we propose to use twisted-mass lattice QCD for the actual computation of the quantities taking part to the averages. The choice ±π/2 for the twisting angle is particularly interesting, as O(a) improved estimates of physical quantities can be obtained even without averaging data from lattice formulations with opposite Wilson terms. In all cases little or no extra computing power is necessary, compared to simulations with standard Wilson fermions or twisted-mass lattice QCD. (author)
Towards a nonperturbative calculation of weak Hamiltonian Wilson coefficients
Bruno, Mattia; Lehner, Christoph; Soni, Amarjit; Rbc; Ukqcd Collaborations
2018-04-01
We propose a method to compute the Wilson coefficients of the weak effective Hamiltonian to all orders in the strong coupling constant using Lattice QCD simulations. We perform our calculations adopting an unphysically light weak boson mass of around 2 GeV. We demonstrate that systematic errors for the Wilson coefficients C1 and C2 , related to the current-current four-quark operators, can be controlled and present a path towards precise determinations in subsequent works.
Nucleon electromagnetic form factors with Wilson fermions
International Nuclear Information System (INIS)
Goeckeler, M.; Haegler, P.; Horsley, R.
2007-10-01
The nucleon electromagnetic form factors continue to be of major interest for experimentalists and phenomenologists alike. They provide important insights into the structure of nuclear matter. For a range of interesting momenta they can be calculated on the lattice. The limiting factor continues to be the value of the pion mass. We present the latest results of the QCDSF collaboration using gauge configurations with two dynamical, non-perturbatively improved Wilson fermions at pion masses as low as 350 MeV. (orig.)
Nucleon electromagnetic form factors with Wilson fermions
Energy Technology Data Exchange (ETDEWEB)
Goeckeler, M. [Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Haegler, P. [Technische Univ. Muenchen, Garching (Germany). Inst. fuer Theoretische Physik; Horsley, R. [Edinburgh Univ. (GB). School of Physics] (and others)
2007-10-15
The nucleon electromagnetic form factors continue to be of major interest for experimentalists and phenomenologists alike. They provide important insights into the structure of nuclear matter. For a range of interesting momenta they can be calculated on the lattice. The limiting factor continues to be the value of the pion mass. We present the latest results of the QCDSF collaboration using gauge configurations with two dynamical, non-perturbatively improved Wilson fermions at pion masses as low as 350 MeV. (orig.)
B-physics with N{sub f}=2 Wilson fermions
Energy Technology Data Exchange (ETDEWEB)
Bernardoni, F.; Simma, H.; Sommer, R. [John von Neumann-Institut fuer Computing NIC/DESY, Zeuthen (Germany)] [and others
2013-09-15
We report the final results of the ALPHA collaboration for some B-physics observables: f{sub B}, f{sub B{sub s}} and m{sub b}. We employ CLS configurations with 2 flavors of O(a) improved Wilson fermions in the sea and pion masses ranging down to 190 MeV. The b-quark is treated in HQET to order 1/m{sub b}. The renormalization, the matching and the improvement were performed non-perturbatively, and three lattice spacings reaching a=0.048 fm are used in the continuum extrapolation.
Determination of csw in Nf=3+1 lattice QCD with massive Wilson fermions
International Nuclear Information System (INIS)
Fritzsch, Patrick; Stollenwerk, Felix; Wolff, Ulli; Sommer, Rainer
2015-01-01
We develop a strategy for the non-perturbative determination of the O(a)-improvement coefficient c sw for Wilson fermions with massive sea quarks. The improvement condition is defined via the PCAC relation in the Schroedinger functional. It is imposed along a line of constant physics designed to be close to the correct mass of the charm quark. The numerical work uses the tree-level improved Luescher-Weisz gauge action in N f =3+1 Lattice QCD.
Fundamental parameters of QCD from non-perturbative methods for two and four flavors
International Nuclear Information System (INIS)
Marinkovic, Marina
2013-01-01
The non-perturbative formulation of Quantumchromodynamics (QCD) on a four dimensional space-time Euclidean lattice together with the finite size techniques enable us to perform the renormalization of the QCD parameters non-perturbatively. In order to obtain precise predictions from lattice QCD, one needs to include the dynamical fermions into lattice QCD simulations. We consider QCD with two and four mass degenerate flavors of O(a) improved Wilson quarks. In this thesis, we improve the existing determinations of the fundamental parameters of two and four flavor QCD. In four flavor theory, we compute the precise value of the Λ parameter in the units of the scale L max defined in the hadronic regime. We also give the precise determination of the Schroedinger functional running coupling in four flavour theory and compare it to the perturbative results. The Monte Carlo simulations of lattice QCD within the Schroedinger Functional framework were performed with a platform independent program package Schroedinger Funktional Mass Preconditioned Hybrid Monte Carlo (SF-MP-HMC), developed as a part of this project. Finally, we compute the strange quark mass and the Λ parameter in two flavour theory, performing a well-controlled continuum limit and chiral extrapolation. To achieve this, we developed a universal program package for simulating two flavours of Wilson fermions, Mass Preconditioned Hybrid Monte Carlo (MP-HMC), which we used to run large scale simulations on small lattice spacings and on pion masses close to the physical value.
Non-perturbative power corrections to ghost and gluon propagators
International Nuclear Information System (INIS)
Boucaud, Philippe; Leroy, Jean-Pierre; Yaouanc, Alain Le; Lokhov, Alexey; Micheli, Jacques; Pene, Olivier; RodrIguez-Quintero, Jose; Roiesnel, Claude
2006-01-01
We study the dominant non-perturbative power corrections to the ghost and gluon propagators in Landau gauge pure Yang-Mills theory using OPE and lattice simulations. The leading order Wilson coefficients are proven to be the same for both propagators. The ratio of the ghost and gluon propagators is thus free from this dominant power correction. Indeed, a purely perturbative fit of this ratio gives smaller value ( ≅ 270MeV) of Λ M-barS-bar than the one obtained from the propagators separately( ≅ 320MeV). This argues in favour of significant non-perturbative ∼ 1/q 2 power corrections in the ghost and gluon propagators. We check the self-consistency of the method
Non-perturbative running of quark masses in three-flavour QCD
Campos, Isabel; Pena, Carlos; Preti, David; Ramos, Alberto; Vladikas, Anastassios
2016-01-01
We present our preliminary results for the computation of the non-perturbative running of renormalized quark masses in $N_f = 3$ QCD, between the electroweak and hadronic scales, using standard finite-size scaling techniques. The computation is carried out to very high precision, using massless $\\mathcal{O}(a)$-improved Wilson quarks. Following the strategy adopted by the ALPHA Collaboration for the running coupling, different schemes are used above and below a scale $\\mu_0 \\sim m_b$, which differ by using either the Schr\\"odinger Functional or Gradient Flow renormalized coupling. We discuss our results for the running in both regions, and the procedure to match the two schemes.
HQET at order 1/m. Pt. 1. Non-perturbative parameters in the quenched approximation
International Nuclear Information System (INIS)
Blossier, Benoit; Della Morte, Michele; Garron, Nicolas; Edinburgh Univ.; Sommer, Rainer
2010-01-01
We determine non-perturbatively the parameters of the lattice HQET Lagrangian and those of heavy-light axial-vector and vector currents in the quenched approximation. The HQET expansion includes terms of order 1/m b . Our results allow to compute, for example, the heavy-light spectrum and B-meson decay constants in the static approximation and to order 1/m b in HQET. The determination of the parameters is separated into universal and non-universal parts. The universal results can be used to determine the parameters for various discretizations. The computation reported in this paper uses the plaquette gauge action and the ''HYP1/2'' action for the b-quark described by HQET. The parameters of the currents also depend on the light-quark action, for which we choose non-perturbatively O(a)-improved Wilson fermions. (orig.)
HQET at order 1/m. Pt. 1. Non-perturbative parameters in the quenched approximation
Energy Technology Data Exchange (ETDEWEB)
Blossier, Benoit [Paris XI Univ., 91 - Orsay (France). Lab. de Physique Theorique; Della Morte, Michele [Mainz Univ. (Germany). Inst. fuer Kernphysik; Garron, Nicolas [Universidad Autonoma de Madrid (Spain). Dept. Fisica Teorica y Inst. de Fisica Teorica UAM/CSIC; Edinburgh Univ. (United Kingdom). School of Physics and Astronomy - SUPA; Sommer, Rainer [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC
2010-01-15
We determine non-perturbatively the parameters of the lattice HQET Lagrangian and those of heavy-light axial-vector and vector currents in the quenched approximation. The HQET expansion includes terms of order 1/m{sub b}. Our results allow to compute, for example, the heavy-light spectrum and B-meson decay constants in the static approximation and to order 1/m{sub b} in HQET. The determination of the parameters is separated into universal and non-universal parts. The universal results can be used to determine the parameters for various discretizations. The computation reported in this paper uses the plaquette gauge action and the ''HYP1/2'' action for the b-quark described by HQET. The parameters of the currents also depend on the light-quark action, for which we choose non-perturbatively O(a)-improved Wilson fermions. (orig.)
Non-perturbative improvement of stout-smeared three flavour clover fermions
Energy Technology Data Exchange (ETDEWEB)
Cundy, N.; Goeckeler, M. [Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Horsley, R. [Edinburgh Univ. (GB). School of Physics and Astronomy] (and others)
2009-01-15
We discuss a 3-flavour 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 Non-perturbative Clover or SLiNC action. To cancel O(a) terms the clover term coefficient has to be tuned. We present here results of a non-perturbative 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. (orig.)
Wilson loops to 20th order numerical stochastic perturbation theory
Energy Technology Data Exchange (ETDEWEB)
Horsley, R. [Edinburgh Univ. (United Kingdom). School of Physics; Hotzel, G.; Perlt, H.; Schiller, A. [Leipzig Univ. (Germany). Inst. fuer Theoretische Physik; Ilgenfritz, E.M. [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Joint Institute for Nuclear Research, VBLHEP, Dubna (Russian Federation); Millo, R.; Rakow, P.E.L. [Liverpool Univ. (Germany). Theoretical Physics Div.; Nakamura, Y. [RIKEN Advanced Institute for Computational Science, Kobe, Hyogo (Japan); Schierholz, G. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2012-05-15
We calculate Wilson loops of various sizes up to 20 loops in SU(3) pure lattice gauge theory at different lattice sizes for Wilson gauge action using the technique of numerical stochastic perturbation theory. This allows us to investigate the perturbative series for various Wilson loops at high loop orders. We observe differences in the behavior of those series as function of the loop order. Up to n=20 we do not find evidence for the factorial growth of the expansion coefficients often assumed to characterize an asymptotic series. Based on the actually observed behavior we sum the series in a model parametrized by hypergeometric functions. Alternatively we estimate the total series in boosted perturbation theory using information from the first 14 loops. We introduce generalized ratios of Wilson loops of different sizes. Together with the corresponding Wilson loops from standard Monte Carlo measurements they enable us to assess their non-perturbative parts.
Renormalisation constants of quark bilinears in lattice QCD with four dynamical Wilson quarks
Energy Technology Data Exchange (ETDEWEB)
Blossier, Benoit [CNRS et Paris-Sud 11 Univ., Orsay (France). Lab. de Physique Theorique; Brinet, Mariane [CNRS/IN2P3/UJF, Grenoble (France). Lab. de Physique Subatomique et de Cosmologie; Carrasco, Nuria [Valencia Univ., Burjassot (ES). Dept. de Fisica Teorica and IFC] (and others)
2011-12-15
We present preliminary results of the non-perturbative computation of the RI-MOM renormalization constants in a mass-independent scheme for the action with Iwasaki glue and four dynamical Wilson quarks employed by ETMC. Our project requires dedicated gauge ensembles with four degenerate sea quark flavours at three lattice spacings and at several values of the standard and twisted quark mass parameters. The RI-MOM renormalization constants are obtained from appropriate O(a) improved estimators extrapolated to the chiral limit. (orig.)
Renormalisation constants of quark bilinears in lattice QCD with four dynamical Wilson quarks
International Nuclear Information System (INIS)
Blossier, Benoit; Brinet, Mariane; Carrasco, Nuria
2011-12-01
We present preliminary results of the non-perturbative computation of the RI-MOM renormalization constants in a mass-independent scheme for the action with Iwasaki glue and four dynamical Wilson quarks employed by ETMC. Our project requires dedicated gauge ensembles with four degenerate sea quark flavours at three lattice spacings and at several values of the standard and twisted quark mass parameters. The RI-MOM renormalization constants are obtained from appropriate O(a) improved estimators extrapolated to the chiral limit. (orig.)
B→π form factor with 2 flavours of O(a) improved Wilson quarks
International Nuclear Information System (INIS)
Bahr, Felix; Bernardoni, Fabio; Ramos, Alberto; Simma, Hubert; Sommer, Rainer; Bulava, John
2012-10-01
The determinations of vertical stroke V ub vertical stroke from the exclusive branching ratios of B→τν and B→πlν tend to show a tension at the level of 3σ. On the theoretical side they depend on the lattice computation of the hadronic matrix elements f B and the B →>π form factor f + (q 2 ). To understand the tension, improved precision and a careful analysis of the systematics involved are necessary. Working towards this goal, we present preliminary lattice results of the ALPHA collaboration for the B→ π form factor f + (q 2 ) with N f =2 flavours of O(a)-improved Wilson fermions. Our computation uses HQET in the static limit, pion masses ranging down to ∼250 MeV, large volumes with m π L>4, three lattice spacings, and non-perturbative renormalization. We describe the techniques adopted to reduce the statistical noise (stochastic all-to-all with full time dilution) and the contamination from excited states (smearing for the B and the pion). We estimate the size of the chiral and continuum extrapolations. We discuss the impact our result could have to clarify the above mentioned discrepancy in the determination of vertical stroke V ub vertical stroke.
B-physics from non-perturbatively renormalized HQET in two-flavour lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Bernardoni, Fabio; Simma, Hubert [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Blossier, Benoit; Gerardin, Antoine [Paris-11 Univ., 91 - Orsay (France). Lab. de Physique Theorique; CNRS, Orsay (France); Bulava, John [CERN, Geneva (Switzerland). Physics Department; Della Morte, Michele; Hippel, Georg M. von [Mainz Univ. (Germany). Inst. fuer Kernphysik; Fritzsch, Patrick [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Garron, Nicolas [Trinity College, Dublin (Ireland). School of Mathematics; Heitger, Jochen [Muenster Univ. (Germany). Inst. fuer Theoretische Physik 1; Collaboration: ALPHA Collaboration
2012-10-15
We report on the ALPHA Collaboration's lattice B-physics programme based on N{sub f}=2 O(a) improved Wilson fermions and HQET, including all NLO effects in the inverse heavy quark mass, as well as non-perturbative renormalization and matching, to fix the parameters of the effective theory. Our simulations in large physical volume cover 3 lattice spacings a {approx} (0.08-0.05) fm and pion masses down to 190 MeV to control continuum and chiral extrapolations. We present the status of results for the b-quark mass and the B{sub (s)}-meson decay constants, f{sub B} and f{sub B{sub s}}.
Renormalisation constants of quark bilinears in lattice QCD with four dynamical Wilson quarks
Blossier, B.; Brinet, M.; Carrasco, N.; Dimopoulos, P.; Du, X.; Frezzotti, R.; Gimenez, V.; Herdoiza, G.; Jansen, K.; Lubicz, V.; Palao, D.; Pallante, E.; Pene, O.; Petrov, K.; Reker, S.; Rossi, G. C.; Sanfilippo, F.; Scorzato, L.; Simula, S.; Urbach, C.
2011-01-01
We present preliminary results of the non-perturbative computation of the RI-MOM renormalisation constants in a mass-independent scheme for the action with Iwasaki glue and four dynamical Wilson quarks employed by ETMC. Our project requires dedicated gauge ensembles with four degenerate sea quark
Perturbative evaluation of the Thermal Wilson Loop
International Nuclear Information System (INIS)
Gava, E.; Jengo, R.
1981-06-01
The Thermal Wilson Loop 0 sup(β) dtauA 0 (tau, x-vector)>, representing an order parameter for the gauge theory and expected to be zero in the confining phase, is perturbatively evaluated up to the O(g 4 ) included for an SU(N) pure Yang-Mills theory. This evaluation should be meaningful at high temperature, β → 0. Its behaviour is discussed and a possible need for non-perturbative instanton-like contributions is pointed out. (author)
Non-perturbative renormalization of left-left four-fermion operators in quenched lattice QCD
Guagnelli, M; Peña, C; Sint, S; Vladikas, A
2006-01-01
We define a family of Schroedinger Functional renormalization schemes for the four-quark multiplicatively renormalizable operators of the $\\Delta F = 1$ and $\\Delta F = 2$ effective weak Hamiltonians. Using the lattice regularization with quenched Wilson quarks, we compute non-perturbatively the renormalization group running of these operators in the continuum limit in a large range of renormalization scales. Continuum limit extrapolations are well controlled thanks to the implementation of two fermionic actions (Wilson and Clover). The ratio of the renormalization group invariant operator to its renormalized counterpart at a low energy scale, as well as the renormalization constant at this scale, is obtained for all schemes.
Non-perturbative renormalisation of left-left four-fermion operators with Neuberger fermions
International Nuclear Information System (INIS)
Dimopoulos, P.; Giusti, L.; Hernandez, P.; Palombi, F.; Pena, C.; Vladikas, A.; Wennekers, J.; Wittig, H.
2006-01-01
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
Very high order lattice perturbation theory for Wilson loops
International Nuclear Information System (INIS)
Horsley, R.
2010-10-01
We calculate perturbativeWilson loops of various sizes up to loop order n=20 at different lattice sizes for pure plaquette and tree-level improved Symanzik gauge theories using the technique of Numerical Stochastic Perturbation Theory. This allows us to investigate the behavior of the perturbative series at high orders. We observe differences in the behavior of perturbative coefficients as a function of the loop order. Up to n=20 we do not see evidence for the often assumed factorial growth of the coefficients. Based on the observed behavior we sum this series in a model with hypergeometric functions. Alternatively we estimate the series in boosted perturbation theory. Subtracting the estimated perturbative series for the average plaquette from the non-perturbative Monte Carlo result we estimate the gluon condensate. (orig.)
Improved quasi parton distribution through Wilson line renormalization
Energy Technology Data Exchange (ETDEWEB)
Chen, Jiunn-Wei [Department of Physics, Center for Theoretical Sciences, and Leung Center for Cosmology and Particle Astrophysics, National Taiwan University, Taipei, 106, Taiwan (China); Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Ji, Xiangdong [INPAC, Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240 (China); Maryland Center for Fundamental Physics, Department of Physics, University of Maryland, College Park, MD 20742 (United States); Zhang, Jian-Hui, E-mail: jianhui.zhang@physik.uni-regensburg.de [Institut für Theoretische Physik, Universität Regensburg, D-93040 Regensburg (Germany)
2017-02-15
Recent developments showed that hadron light-cone parton distributions could be directly extracted from spacelike correlators, known as quasi parton distributions, in the large hadron momentum limit. Unlike the normal light-cone parton distribution, a quasi parton distribution contains ultraviolet (UV) power divergence associated with the Wilson line self energy. We show that to all orders in the coupling expansion, the power divergence can be removed by a “mass” counterterm in the auxiliary z-field formalism, in the same way as the renormalization of power divergence for an open Wilson line. After adding this counterterm, the quasi quark distribution is improved such that it contains at most logarithmic divergences. Based on a simple version of discretized gauge action, we present the one-loop matching kernel between the improved non-singlet quasi quark distribution with a lattice regulator and the corresponding quark distribution in dimensional regularization.
Improved quasi parton distribution through Wilson line renormalization
Directory of Open Access Journals (Sweden)
Jiunn-Wei Chen
2017-02-01
Full Text Available Recent developments showed that hadron light-cone parton distributions could be directly extracted from spacelike correlators, known as quasi parton distributions, in the large hadron momentum limit. Unlike the normal light-cone parton distribution, a quasi parton distribution contains ultraviolet (UV power divergence associated with the Wilson line self energy. We show that to all orders in the coupling expansion, the power divergence can be removed by a “mass” counterterm in the auxiliary z-field formalism, in the same way as the renormalization of power divergence for an open Wilson line. After adding this counterterm, the quasi quark distribution is improved such that it contains at most logarithmic divergences. Based on a simple version of discretized gauge action, we present the one-loop matching kernel between the improved non-singlet quasi quark distribution with a lattice regulator and the corresponding quark distribution in dimensional regularization.
Non-Perturbative Asymptotic Improvement of Perturbation Theory and Mellin-Barnes Representation
Directory of Open Access Journals (Sweden)
Samuel Friot
2010-10-01
Full Text Available Using a method mixing Mellin-Barnes representation and Borel resummation we show how to obtain hyperasymptotic expansions from the (divergent formal power series which follow from the perturbative evaluation of arbitrary ''N-point'' functions for the simple case of zero-dimensional φ4 field theory. This hyperasymptotic improvement appears from an iterative procedure, based on inverse factorial expansions, and gives birth to interwoven non-perturbative partial sums whose coefficients are related to the perturbative ones by an interesting resurgence phenomenon. It is a non-perturbative improvement in the sense that, for some optimal truncations of the partial sums, the remainder at a given hyperasymptotic level is exponentially suppressed compared to the remainder at the preceding hyperasymptotic level. The Mellin-Barnes representation allows our results to be automatically valid for a wide range of the phase of the complex coupling constant, including Stokes lines. A numerical analysis is performed to emphasize the improved accuracy that this method allows to reach compared to the usual perturbative approach, and the importance of hyperasymptotic optimal truncation schemes.
Non-perturbative O(a) improvement of lattice QCD
Lüscher, Martin; Sommer, Rainer; Weisz, P; Wolff, U; Luescher, Martin; Sint, Stefan; Sommer, Rainer; Weisz, Peter; Wolff, Ulli
1997-01-01
The coefficients multiplying the counterterms required for O($a$) improvement of the action and the isovector axial current in lattice QCD are computed non-perturbatively, in the quenched approximation and for bare gauge couplings $g_0$ in the range $0 \\leq g_0 \\leq 1$. A finite-size method based on the Schrödinger functional is employed, which enables us to perform all calculations at zero or nearly zero quark mass. As a by-product the critical hopping parameter $\\kappa_c$ is obtained at all couplings considered.
On the chirally rotated Schroedinger functional with Wilson fermions
International Nuclear Information System (INIS)
Gonzalez Lopez, Jenifer
2011-01-01
There are many phenomena in nature, which are closely linked to the low energy regime of QCD. From a theoretical point of view, these low energy phenomena can be dealt with only by means of non-perturbative methods. It is the central goal of this thesis to provide a framework for such a nonperturbative renormalization. For that purpose, we employ a 4-dimensional lattice as a regulator of QCD. As a renormalization scheme, we propose a finite volume Schroedinger functional scheme and here in particular, the chirally rotated Schroedinger functional (χSF). We first perform analytical studies of the χSF at tree-level of perturbation theory, in the continuum and on the lattice. We study the eigenvalue spectrum of the continuum Dirac operator, equipped with chirally rotated SF boundary conditions, and derive the corresponding quark propagator. We then determine the tree-level quark propagator on the lattice, employing massless Wilson fermions as a regulator of the theory. Beyond tree-level, all studies are performed in the quenched approximation of QCD, as a first, computationally much simpler step to understand the properties of the newly proposed χSF scheme. One of the main targets of the present work, has been to perform the non-perturbative tuning of the two required coefficients of the χSF scheme, such that a well defined continuum limit can be reached. We demonstrate, as the first main result of this thesis, that the tuning is feasible and that, moreover, physical quantities are insensitive to the particular tuning condition. As in any lattice regularization with SF-like boundary conditions, there are also in the χSF a couple of counterterms at the boundaries, whose coefficients need to be tuned in order to remove the O(a) discretization effects originated at the boundaries. However, besides these boundary O(a) effects, the χSF is expected to be compatible with bulk automatic O(a)-improvement. We show here that, indeed, the scaling behavior of physical
On the chirally rotated Schroedinger functional with Wilson fermions
Energy Technology Data Exchange (ETDEWEB)
Gonzalez Lopez, Jenifer
2011-05-25
There are many phenomena in nature, which are closely linked to the low energy regime of QCD. From a theoretical point of view, these low energy phenomena can be dealt with only by means of non-perturbative methods. It is the central goal of this thesis to provide a framework for such a nonperturbative renormalization. For that purpose, we employ a 4-dimensional lattice as a regulator of QCD. As a renormalization scheme, we propose a finite volume Schroedinger functional scheme and here in particular, the chirally rotated Schroedinger functional ({chi}SF). We first perform analytical studies of the {chi}SF at tree-level of perturbation theory, in the continuum and on the lattice. We study the eigenvalue spectrum of the continuum Dirac operator, equipped with chirally rotated SF boundary conditions, and derive the corresponding quark propagator. We then determine the tree-level quark propagator on the lattice, employing massless Wilson fermions as a regulator of the theory. Beyond tree-level, all studies are performed in the quenched approximation of QCD, as a first, computationally much simpler step to understand the properties of the newly proposed {chi}SF scheme. One of the main targets of the present work, has been to perform the non-perturbative tuning of the two required coefficients of the {chi}SF scheme, such that a well defined continuum limit can be reached. We demonstrate, as the first main result of this thesis, that the tuning is feasible and that, moreover, physical quantities are insensitive to the particular tuning condition. As in any lattice regularization with SF-like boundary conditions, there are also in the {chi}SF a couple of counterterms at the boundaries, whose coefficients need to be tuned in order to remove the O(a) discretization effects originated at the boundaries. However, besides these boundary O(a) effects, the {chi}SF is expected to be compatible with bulk automatic O(a)-improvement. We show here that, indeed, the scaling behavior
International Nuclear Information System (INIS)
Makeenko, Yu.M.; Polikarpov, M.I.; Zhelonkin, A.V.
1983-01-01
The mixed SU(2) lattice gauge theory (LGT) is approximately represented as an effective SU(2) LGT with Wilson's action. This approach is applied to the nonperturbative calculation of the ratio of Λ-parameters in the mixed SU(2) LGT. It is shown that the formulas obtained fairly describe the Monte Carlo data so that universality holds in the mixed SU(2) LGT
A complete non-perturbative renormalization prescription for quasi-PDFs
Energy Technology Data Exchange (ETDEWEB)
Alexandrou, Constantia [Cyprus Univ., Nicosia (Cyprus). Dept. of Physics; The Cyprus Institute, Nicosia (Cyprus); Cichy, Krzysztof [Frankfurt Univ. (Germany). Inst. fuer Theoretische Physik; Adam Mickiewicz Univ., Poznan (Poland). Faculty of Physics; Constantinou, Martha [Temple Univ., Philadelphia, PA (United States). Dept. of Physics; Hadjiyiannakou, Kyriakos [The Cyprus Institute, Nicosia (Cyprus); Jansen, Karl; Steffens, Fernanda [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Panagopoulos, Haralambos [Cyprus Univ., Nicosia (Cyprus). Dept. of Physics; Collaboration: European Twisted Mass Collaboration
2017-06-15
In this work we present, for the first time, the non-perturbative renormalization for the unpolarized, helicity and transversity quasi-PDFs, in an RI{sup '} scheme. The proposed prescription addresses simultaneously all aspects of renormalization: logarithmic divergences, finite renormalization as well as the linear divergence which is present in the matrix elements of fermion operators with Wilson lines. Furthermore, for the case of the unpolarized quasi-PDF, we describe how to eliminate the unwanted mixing with the twist-3 scalar operator. We utilize perturbation theory for the one-loop conversion factor that brings the renormalization functions to the MS-scheme at a scale of 2 GeV. We also explain how to improve the estimates on the renormalization functions by eliminating lattice artifacts. The latter can be computed in one-loop perturbation theory and to all orders in the lattice spacing. We apply the methodology for the renormalization to an ensemble of twisted mass fermions with N{sub f}=2+1+1 dynamical quarks, and a pion mass of around 375 MeV.
Trottier, H. D.; Shakespeare, N. H.; Lepage, G. P.; MacKenzie, P. B.
2002-05-01
Perturbative coefficients for Wilson loops and the static-quark self-energy are extracted from Monte Carlo simulations at weak coupling. The lattice volumes and couplings are chosen to ensure that the lattice momenta are all perturbative. Twisted boundary conditions are used to eliminate the effects of lattice zero modes and to suppress nonperturbative finite-volume effects due to Z(3) phases. Simulations of the Wilson gluon action are done with both periodic and twisted boundary conditions, and over a wide range of lattice volumes (from 34 to 164) and couplings (from β~9 to β~60). A high precision comparison is made between the simulation data and results from finite-volume lattice perturbation theory. The Monte Carlo results are shown to be in excellent agreement with perturbation theory through second order. New results for third-order coefficients for a number of Wilson loops and the static-quark self-energy are reported.
ON-SHELL IMPROVEMENT OF THE MASSIVE WILSON QUARK ACTION.
Energy Technology Data Exchange (ETDEWEB)
AOKI, S.; KAYABA, Y.; KURAMASHI, Y.; YAMADA, N.
2005-04-01
We review a relativistic approach to the heavy quark physics in lattice QCD by applying a relativistic O(a) improvement to the massive Wilson quark action on the lattice. After explaining how power corrections of m{sub Q}a can be avoided and remaining uncertainties are reduced to be of order (a{Lambda}{sub QCD}){sup 2}, we demonstrate a determination of four improvement coefficients in the action up to one-loop level in a mass dependent way. We also show a perturbative determination of mass dependent renormalization factors and O(a) improvement coefficients for the vector and axial vector currents. Some preliminary results of numerical simulations are also presented.
Energy Technology Data Exchange (ETDEWEB)
Constantinou, M. [Cyprus Univ., Nicosia (Cyprus). Dept. of Physics; Dimopoulos, P. [Roma ' ' La Sapienza' ' Univ. (Italy). Dipt. di Fisica; INFN, Rome (Italy); Frezzotti, R. [Roma ' ' Tor Vergata' ' Univ. (Italy). Dipt. di Fisica; INFN, Roma (IT)] (and others)
2010-06-15
We present results for the renormalization constants of bilinear quark operators obtained b4>UNL<426>UNL using the tree-level Symanzik improved gauge action and the N{sub f}=2 twisted mass fermion action at maximal twist, which guarantees automatic O(a)- improvement. Our results are also relevant for the corresponding standard (untwisted) Wilson fermionic action since the two actions only differ, in the massless limit, by a chiral rotation of the quark fields. The scale-independent renormalization constants Z{sub V}, Z{sub A} and the ratio Z{sub P}/Z{sub S} have been computed using the RI-MOM approach, as well as other alternative methods. For Z{sub A} and Z{sub P}/Z{sub S}, the latter are based on both standard twisted mass and Osterwalder-Seiler fermions, while for Z{sub V} a Ward Identity has been used. The quark field renormalization constant Z{sub q} and the scale dependent renormalization constants Z{sub S}, Z{sub P} and Z{sub T} are determined in the RI-MOM scheme. Leading discretization effects of O(g{sup 2}a{sup 2}), evaluated in one-loop perturbation theory, are explicitly subtracted from the RI-MOM estimates. (orig.)
International Nuclear Information System (INIS)
Trottier, H.D.; Shakespeare, N.H.; Lepage, G.P.; Mackenzie, P.B.
2002-01-01
Perturbative coefficients for Wilson loops and the static-quark self-energy are extracted from Monte Carlo simulations at weak coupling. The lattice volumes and couplings are chosen to ensure that the lattice momenta are all perturbative. Twisted boundary conditions are used to eliminate the effects of lattice zero modes and to suppress nonperturbative finite-volume effects due to Z(3) phases. Simulations of the Wilson gluon action are done with both periodic and twisted boundary conditions, and over a wide range of lattice volumes (from 3 4 to 16 4 ) and couplings (from β≅9 to β≅60). A high precision comparison is made between the simulation data and results from finite-volume lattice perturbation theory. The Monte Carlo results are shown to be in excellent agreement with perturbation theory through second order. New results for third-order coefficients for a number of Wilson loops and the static-quark self-energy are reported
Energy Technology Data Exchange (ETDEWEB)
Green, Jeremy; Jansen, Karl; Steffens, Fernanda [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC
2017-07-15
Quasi-PDFs provide a path toward an ab initio calculation of parton distribution functions (PDFs) using lattice QCD. One of the problems faced in calculations of quasi-PDFs is the renormalization of a nonlocal operator. By introducing an auxiliary field, we can replace the nonlocal operator with a pair of local operators in an extended theory. On the lattice, this is closely related to the static quark theory. In this approach, we show how to understand the pattern of mixing that is allowed by chiral symmetry breaking, and obtain a master formula for renormalizing the nonlocal operator that depends on three parameters. We present an approach for nonperturbatively determining these parameters and use perturbation theory to convert to the MS scheme. Renormalization parameters are obtained for two lattice spacings using Wilson twisted mass fermions and for different discretizations of the Wilson line in the nonlocal operator. Using these parameters we show the effect of renormalization on nucleon matrix elements with pion mass approximately 370 MeV, and compare renormalized results for the two lattice spacings. The renormalized matrix elements are consistent among the different Wilson line discretizations and lattice spacings.
International Nuclear Information System (INIS)
Green, Jeremy; Jansen, Karl; Steffens, Fernanda
2017-07-01
Quasi-PDFs provide a path toward an ab initio calculation of parton distribution functions (PDFs) using lattice QCD. One of the problems faced in calculations of quasi-PDFs is the renormalization of a nonlocal operator. By introducing an auxiliary field, we can replace the nonlocal operator with a pair of local operators in an extended theory. On the lattice, this is closely related to the static quark theory. In this approach, we show how to understand the pattern of mixing that is allowed by chiral symmetry breaking, and obtain a master formula for renormalizing the nonlocal operator that depends on three parameters. We present an approach for nonperturbatively determining these parameters and use perturbation theory to convert to the MS scheme. Renormalization parameters are obtained for two lattice spacings using Wilson twisted mass fermions and for different discretizations of the Wilson line in the nonlocal operator. Using these parameters we show the effect of renormalization on nucleon matrix elements with pion mass approximately 370 MeV, and compare renormalized results for the two lattice spacings. The renormalized matrix elements are consistent among the different Wilson line discretizations and lattice spacings.
Non-perturbative renormalization of HQET and QCD
International Nuclear Information System (INIS)
Sommer, Rainer
2003-01-01
We discuss the necessity of non-perturbative renormalization in QCD and HQET and explain the general strategy for solving this problem. A few selected topics are discussed in some detail, namely the importance of off shell improvement in the MOM-scheme on the lattice, recent progress in the implementation of finite volume schemes and then particular emphasis is put on the recent idea to carry out a non-perturbative renormalization of the Heavy Quark Effective Theory (HQET)
String breaking with Wilson loops?
Kratochvila, S; Kratochvila, Slavo; Forcrand, Philippe de
2003-01-01
A convincing, uncontroversial observation of string breaking, when the static potential is extracted from Wilson loops only, is still missing. This failure can be understood if the overlap of the Wilson loop with the broken string is exponentially small. In that case, the broken string ground state will only be seen if the Wilson loop is long enough. Our preliminary results show string breaking in the context of the 3d SU(2) adjoint static potential, using the L\\"uscher-Weisz exponential variance reduction approach. As a by-product, we measure the fundamental SU(2) static potential with improved accuracy and see clear deviations from Casimir scaling.
Non-perturbative renormalisation of {delta}F=2 four-fermion operators in two-flavour QCD
Energy Technology Data Exchange (ETDEWEB)
Dimopoulos, P.; Vladikas, A. [INFN, Sezione di Roma II (Italy)]|[Rome-3 Univ. (Italy). Dipt. di Fisica; Herdoiza, G. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Palombi, F.; Papinutto, M. [CERN, Geneva (Switzerland). Physics Dept., TH Division; Pena, C. [Universidad Autonoma de Madrid (Spain). Dept. de Fisica Teorica C-XI]|[Univ. Autonoma de Madrid (Spain). Inst. de Fisica Teorica UAM/CSIC C-XVI; Wittig, H. [Mainz Univ. (Germany). Inst. fuer Kernphysik
2007-12-15
Using Schroedinger Functional methods, we compute the non-perturbative renormalisation and renormalisation group running of several four-fermion operators, in the framework of lattice simulations with two dynamical Wilson quarks. Two classes of operators have been targeted: (i) those with left-left current structure and four propagating quark fields; (ii) all operators containing two static quarks. In both cases, only the parity-odd contributions have been considered, being the ones that renormalise multiplicatively. Our results, once combined with future simulations of the corresponding lattice hadronic matrix elements, may be used for the computation of phenomenological quantities of interest, such as B{sub K} and B{sub B} (the latter also in the static limit). (orig.)
Wilson loops in heavy ion collisions and their calculation in AdS/CFT
Liu, H; Wiedemann, Urs Achim; Liu, Hong; Rajagopal, Krishna; Wiedemann, Urs Achim
2007-01-01
Expectation values of Wilson loops define the nonperturbative properties of the hot medium produced in heavy ion collisions that arise in the analysis of both radiative parton energy loss and quarkonium suppression. We use the AdS/CFT correspondence to calculate the expectation values of such Wilson loops in the strongly coupled plasma of N=4 super Yang-Mills (SYM) theory, allowing for the possibility that the plasma may be moving with some collective flow velocity as is the case in heavy ion collisions. We obtain the N=4 SYM values of the jet quenching parameter $\\hat q$, which describes the energy loss of a hard parton in QCD, and of the velocity-dependence of the quark-antiquark screening length for a moving dipole as a function of the angle between its velocity and its orientation. We show that if the quark-gluon plasma is flowing with velocity v_f at an angle theta with respect to the trajectory of a hard parton, the jet quenching parameter $\\hat q$ is modified by a factor gamma_f(1-v_f cos theta), and s...
Nonperturbative flipped SU(5) vacua in heterotic M-theory
Energy Technology Data Exchange (ETDEWEB)
Faraggi, Alon E. E-mail: faraggi@thphys.ox.ac.uk; Garavuso, Richard E-mail: garavuso@thphys.ox.ac.uk; Isidro, Jose M. E-mail: isidro@thphys.ox.ac.uk
2002-10-07
The evidence for neutrino masses in atmospheric and solar neutrino experiments provides further support for the embedding of the Standard Model fermions in the chiral 16 SO(10) representation. Such an embedding is afforded by the realistic free fermionic heterotic-string models. In this paper we advance the study of these string models toward a nonperturbative analysis by generalizing the work of Donagi, Pantev, Ovrut and Waldram from the case of G=SU(2n+1) to G=SU(2n) stable holomorphic vector bundles on elliptically fibered Calabi-Yau manifolds with fundamental group Z{sub 2}. We demonstrate existence of G=SU(4) solutions with three generations and SO(10) observable gauge group over Hirzebruch base surface, whereas we show that certain classes of del Pezzo base surface do not admit such solutions. The SO(10) symmetry is broken to SU(5)xU(1) by a Wilson line. The overlap with the realistic free fermionic heterotic-string models is discussed.
Relativistic corrections to the static energy in terms of Wilson loops at weak coupling
Energy Technology Data Exchange (ETDEWEB)
Peset, Clara [Technische Universitaet Muenchen, Physik Department T31, Garching (Germany); Pineda, Antonio [Universitat Autonoma de Barcelona, Grup de Fisica Teorica, Dept. Fisica y IFAE-BIST, Barcelona (Spain); Stahlhofen, Maximilian [Johannes Gutenberg University, PRISMA Cluster of Excellence, Institute of Physics, Mainz (Germany)
2017-10-15
We consider the O(1/m) and the spin-independent momentum-dependent O(1/m{sup 2}) quasi-static energies of heavy quarkonium (with unequal masses). They are defined nonperturbatively in terms of Wilson loops. We determine their short-distance behavior through O(α{sup 3}) and O(α{sup 2}), respectively. In particular, we calculate the ultrasoft contributions to the quasi-static energies, which requires the resummation of potential interactions. Our results can be directly compared to lattice simulations. In addition, we also compare the available lattice data with the expectations from effective string models for the long-distance behavior of the quasi-static energies. (orig.)
Improved continuum limit lattice action for QCD with Wilson fermions
International Nuclear Information System (INIS)
Sheikholeslami, B.; Wohlert, R.
1985-03-01
Two possible ways of extending Symanzik's improvement programme to lattice fermions namely improvement to first and second order in the lattice spacing 'a' are discussed. The corresponding lattice actions for fermions are constructed and tree level improvement conditions are derived by considering classical improvement. The concept of on shell improvement is generalized to the lattice fermions studied here and the free parameters are determined for O(a) and O(a 2 ) on shell improved actions to all orders of perturbation theory. No evidence is found that the complicated structure of the O(a 2 ) on shell improved action especially the arising fermion contact terms can be removed beyond tree level. The effect of terms in the action that explicitly break chiral symmetry and therefore remove the phenomenon of species doubling are investigated by considering the energy momentum relations of the arising tree level improved actions. Our main result is that the O(a) improved action is a slightly modified Wilson fermion action which can still be written with only nearest neighbour fermion interactions. (orig.)
Observing string breaking with Wilson loops
Kratochvila, S; Kratochvila, Slavo; Forcrand, Philippe de
2003-01-01
An uncontroversial observation of adjoint string breaking is proposed, while measuring the static potential from Wilson loops only. The overlap of the Wilson loop with the broken-string state is small, but non-vanishing, so that the broken-string groundstate can be seen if the Wilson loop is long enough. We demonstrate this in the context of the (2+1)d SU(2) adjoint static potential, using an improved version of the Luscher-Weisz exponential variance reduction. To complete the picture we perform the more usual multichannel analysis with two basis states, the unbroken-string state and the broken-string state (two so-called gluelumps). As by-products, we obtain the temperature-dependent static potential measured from Polyakov loop correlations, and the fundamental SU(2) static potential with improved accuracy. Comparing the latter with the adjoint potential, we see clear deviations from Casimir scaling.
Quark structure from the lattice operator product expansion
International Nuclear Information System (INIS)
Bietenholz, W.; Cundy, N.; Goeckeler, M.
2009-11-01
We have reported elsewhere in this conference on our continuing project to determine nonperturbative Wilson coefficients on the lattice, as a step towards a completely non-perturbative determination of the nucleon structure. In this talk we discuss how these Wilson coefficients can be used to extract Nachtmann moments of structure functions, using the case of off-shell Landau-gauge quarks as a first simple example. This work is done using overlap fermions, because their improved chiral properties reduce the difficulties due to operator mixing. (orig.)
Negative-Parity Baryon Masses Using O(a)-improved Fermion Action
Energy Technology Data Exchange (ETDEWEB)
M. Gockeler; R. Horsley; D. Pleiter; P.E.L. Rakow; G. Schierholz; C.M. Maynard; D.G. Richards
2001-06-01
We present a calculation of the mass of the lowest-lying negative-parity J=1/2{sup {minus}} state in quenched QCD. Results are obtained using a non-perturbatively {Omicron}(a)-improved clover fermion action, and a splitting found between the masses of the nucleon, and its parity partner. The calculation is performed on two lattice volumes, and at three lattice spacings, enabling a study of both finite-volume and finite lattice-spacing uncertainties. A comparison is made with results obtained using the unimproved Wilson fermion action.
Electromagnetic corrections to the hadronic vacuum polarization of the photon within QEDL and QEDM
DEFF Research Database (Denmark)
Della Morte, Michele; Bussone, Andrea; Janowski, Tadeusz
2018-01-01
degenerate flavors of nonperturbatively O(a)-improved Wilson fermions. We consider QEDL and QEDM to deal with the finite-volume zero modes. We compare results for the Wilson loops with exact analytical determinations. In addition we make sure that the volumes and photon masses used in QEDM...
Energy Technology Data Exchange (ETDEWEB)
Brambilla, M.; Di Renzo, F. [Universita di Parma (Italy); INFN, Gruppo Collegato di Parma, Dipartimento di Fisica e Scienze della Terra, Parma (Italy); Hasegawa, M. [Universita di Parma (Italy); Bogoliubov Laboratory of Theoretical Physics, Dubna (Russian Federation); INFN, Gruppo Collegato di Parma, Dipartimento di Fisica e Scienze della Terra, Parma (Italy)
2014-07-15
This is the third of a series of papers on three-loop computation of renormalization constants for Lattice QCD. Our main points of interest are results for the regularization defined by the Iwasaki gauge action and n{sub f} Wilson fermions. Our results for quark bilinears renormalized according to the RI'-MOM scheme can be compared to non-perturbative results. The latter are available for twisted mass QCD: being defined in the chiral limit, the renormalization constants must be the same. We also address more general problems. In particular, we discuss a few methodological issues connected to summing the perturbative series such as the effectiveness of boosted perturbation theory and the disentanglement of irrelevant and finite-volume contributions. Discussing these issues we consider not only the new results of this paper, but also those for the regularization defined by the tree-level Symanzik improved gauge action and n{sub f} Wilson fermions, which we presented in a recent paper of ours. We finally comment on the extent to which the techniques we put at work in the NSPT context can provide a fresher look into the lattice version of the RI'-MOM scheme. (orig.)
Negative-parity baryon masses using an Ο(α)-improved fermion action
International Nuclear Information System (INIS)
Goeckeler, M.; Rakow, P.E.L.; Maynard, C.M.; Richards, D.G.; Old Dominion Univ., Norfolk, VA
2001-06-01
We present a calculation of the mass of the lowest-lying negative-parity J = 1/2 - state in quenched QCD. Results are obtained using a non-perturbatively O(a)-improved clover fermion action, and a splitting is found between the masses of the nucleon, and its parity partner. The calculation is performed on two lattice volumes and at three lattice spacings, enabling a study of both finite-volume and finite lattice-spacing uncertainties. A comparison is made with results obtained using the unimproved Wilson fermion action. (orig.)
Determination of csw in Nf=3+1 lattice QCD with massive Wilson fermions
International Nuclear Information System (INIS)
Stollenwerk, Felix
2017-01-01
In order to obtain sensible results from Lattice QCD that may be compared with experiment, extrapolation to the continuum is crucial. The well-established Symanzik improvement program systematically reduces the order of cutoff effects, allowing for better control of the aforementioned errors, as well as larger and thus more affordable lattice spacings. Applied to the Wilson fermion action, it entails the addition of the Sheikholeslami-Wohlert term with the O(a) improvement coefficient c sw . In this work, a strategy is developed for the non-perturbative determination of c sw in the theory with N f =3+1 massive sea quarks. It is embedded in a general, mass-dependent renormalization and improvement scheme, for which we lay the foundations. The improvement condition, formulated by means of the PCAC relation in the Schroedinger Functional, is imposed along a line of constant physics that is designed to be close to the physical mass of the charm quark. The aim of this rather elaborate approach is to avoid large, mass-dependent O(a 2 ) effects in future large volume simulations with four dynamical quark species. The numerical results are worked out using the tree-level improved Luescher-Weisz gauge action. Since the gradient flow coupling is employed in the definition of the line of constant physics, its interdependence with the topological charge in regard to critical slowing down and topology freezing is investigated in a supplemental study.
Energy Technology Data Exchange (ETDEWEB)
Guazzini, D.; Sommer, R. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Meyer, H. [Massachusetts Institute of Technology, Cambridge, MA (United States). Center for Theoretical Physics
2007-05-15
We carry out the non-perturbative renormalization of the chromo-magnetic operator in Heavy Quark Effective Theory. At order 1/m of the expansion, the operator is responsible for the mass splitting between the pseudoscalar and vector B mesons. We obtain its two-loop anomalous dimension in a Schroedinger functional scheme by successive oneloop conversions to the lattice MS scheme and the MS scheme. We then compute the scale evolution of the operator non-perturbatively in the N{sub f}=0 theory between {mu} {approx}0.3 GeV and {mu} {approx}100 GeV, where contact is made with perturbation theory. The overall renormalization factor that converts the bare lattice operator to its renormalization group invariant form is given for the Wilson gauge action and two standard discretizations of the heavy-quark action. As an application, we find that this factor brings the previous quenched predictions of the B{sup *}-B mass splitting closer to the experimental value than found with a perturbative renormalization. The same renormalization factor is applicable to the spin-dependent potentials of Eichten and Feinberg. (orig.)
arXiv Mass-improvement of the vector current in three-flavor QCD
Fritzsch, Patrick
2018-06-04
We determine two improvement coefficients which are relevant to cancel mass-dependent cutoff effects in correlation functions with operator insertions of the non-singlet local QCD vector current. This determination is based on degenerate three-flavor QCD simulations of non-perturbatively O(a) improved Wilson fermions with tree-level improved gauge action. Employing a very robust strategy that has been pioneered in the quenched approximation leads to an accurate estimate of a counterterm cancelling dynamical quark cutoff effects linear in the trace of the quark mass matrix. To our knowledge this is the first time that such an effect has been determined systematically with large significance.
The running coupling of QCD with four flavors
International Nuclear Information System (INIS)
Tekin, Fatih; Wolff, Ulli; Sommer, Rainer
2010-06-01
We have calculated the step scaling function and the running coupling of QCD in the Schroedinger functional scheme with four flavors of O(a) improved Wilson quarks. Comparisons of our non-perturbative results with 2-loop and 3-loop perturbation theory as well as with non-perturbative data for only two flavors are made. (orig.)
Nonperturbative QCD and elastic processes at CEBAF energies
Energy Technology Data Exchange (ETDEWEB)
Radyushkin, A.V. [Old Dominion Univ., Norfolk, VA (United States)]|[Continuous Electron Beam Accelerator Facility, Newport News, VA (United States)
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.
Nonperturbative QCD and elastic processes at CEBAF energies
International Nuclear Information System (INIS)
Radyushkin, A.V.
1994-01-01
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 knownclose quotes) short-distance effects and nonperturbative (open-quotes unknownclose 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 2 closer to 10 GeV 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
DEFF Research Database (Denmark)
Bownik, Marcin; Jakobsen, Mads Sielemann; Lemvig, Jakob
2017-01-01
A Wilson system is a collection of finite linear combinations of time frequency shifts of a square integrable function. In this paper we give an account of the construction of bimodular Wilson bases in higher dimensions from Gabor frames of redundancy two.......A Wilson system is a collection of finite linear combinations of time frequency shifts of a square integrable function. In this paper we give an account of the construction of bimodular Wilson bases in higher dimensions from Gabor frames of redundancy two....
Samuel Alexander Kinnier Wilson. Wilson's disease, Queen Square and neurology.
Broussolle, E; Trocello, J-M; Woimant, F; Lachaux, A; Quinn, N
2013-12-01
This historical article describes the life and work of the British physician Samuel Alexander Kinnier Wilson (1878-1937), who was one of the world's greatest neurologists of the first half of the 20th century. Early in his career, Wilson spent one year in Paris in 1903 where he learned from Pierre-Marie at Bicêtre Hospital. He subsequently retained uninterrupted links with French neurology. He also visited in Leipzig the German anatomist Paul Flechsig. In 1904, Wilson returned to London, where he worked for the rest of his life at the National Hospital for the Paralysed and Epileptic (later the National Hospital for Nervous Diseases, and today the National Hospital for Neurology and Neurosurgery) in Queen Square, and also at Kings' College Hospital. He wrote on 'the old motor system and the new', on disorders of motility and muscle tone, on the epilepsies, on aphasia, apraxia, tics, and pathologic laughing and crying, and most importantly on Wilson's disease. The other objective of our paper is to commemorate the centenary of Wilson's most important work published in 1912 in Brain, and also in Revue Neurologique, on an illness newly recognized and characterized by him entitled "Progressive lenticular degeneration, a familial nervous disease associated with liver cirrhosis". He analyzed 12 clinical cases, four of whom he followed himself, but also four cases previously published by others and a further two that he considered in retrospect had the same disease as he was describing. The pathological profile combined necrotic damage in the lenticular nuclei of the brain and hepatic cirrhosis. This major original work is summarized and discussed in the present paper. Wilson not only delineated what was later called hepato-lenticular degeneration and Wilson's disease, but also introduced for the first time the terms extrapyramidal syndrome and extrapyramidal system, stressing the role of the basal ganglia in motility. The present historical work emphasizes the special
New Methods in Non-Perturbative QCD
Energy Technology Data Exchange (ETDEWEB)
Unsal, Mithat [North Carolina State Univ., Raleigh, NC (United States)
2017-01-31
In this work, we investigate the properties of quantum chromodynamics (QCD), by using newly developing mathematics and physics formalisms. Almost all of the mass in the visible universe emerges from a quantum chromodynamics (QCD), which has a completely negligible microscopic mass content. An intimately related issue in QCD is the quark confinement problem. Answers to non-perturbative questions in QCD remained largely elusive despite much effort over the years. It is also believed that the usual perturbation theory is inadequate to address these kinds of problems. Perturbation theory gives a divergent asymptotic series (even when the theory is properly renormalized), and there are non-perturbative phenomena which never appear at any order in perturbation theory. Recently, a fascinating bridge between perturbation theory and non-perturbative effects has been found: a formalism called resurgence theory in mathematics tells us that perturbative data and non-perturbative data are intimately related. Translating this to the language of quantum field theory, it turns out that non-perturbative information is present in a coded form in perturbation theory and it can be decoded. We take advantage of this feature, which is particularly useful to understand some unresolved mysteries of QCD from first principles. In particular, we use: a) Circle compactifications which provide a semi-classical window to study confinement and mass gap problems, and calculable prototypes of the deconfinement phase transition; b) Resurgence theory and transseries which provide a unified framework for perturbative and non-perturbative expansion; c) Analytic continuation of path integrals and Lefschetz thimbles which may be useful to address sign problem in QCD at finite density.
MR of the liver in Wilson`s disease; MRT der Leber bei Morbus Wilson
Energy Technology Data Exchange (ETDEWEB)
Vogl, T.J. [Strahlenklinik und Poliklinik, Universitaetsklinikum Rudolf Virchow, Freie Univ. Berlin (Germany); Steiner, S. [Klinikum Grosshadern, Radiologische Klinik und Poliklinik, Univ. Muenchen (Germany); Hammerstingl, R. [Strahlenklinik und Poliklinik, Universitaetsklinikum Rudolf Virchow, Freie Univ. Berlin (Germany); Schwarz, S. [Klinikum Grosshadern, Neurologische Klinik, Univ. Muenchen (Germany); Kraft, E. [Klinikum Grosshadern, Neurologische Klinik, Univ. Muenchen (Germany); Weinzierl, M. [Klinikum Grosshadern, 2. Medizinische Klinik, Univ. Muenchen (Germany); Felix, R. [Strahlenklinik und Poliklinik, Universitaetsklinikum Rudolf Virchow, Freie Univ. Berlin (Germany)
1994-01-01
To show that Wilson`s disease is one likely cause of multiple low-intensity nodules of the liver we obtained MR images in 16 patients with clinically and histopathologically confirmed Wilson`s disease. Corresponding to morphological changes MRI enabled the subdivision of the patients into two groups. Using a T{sub 2}-weighted spin-echo sequence (TR/TE=2000/45-90) liver parenchyma showed multiple tiny low-intensity-nodules surrounded by high-intensity septa in 10 out of 16 patients. 5 patients had also low-intensity nodules in T{sub 1}-weighted images (TR/TE=600/20). In patients of this group histopathology revealed liver cirrhosis (n=7) and fibrosis (n=2). Common feature of this patient group was marked inflammatory cell infiltration into fibrous septa, increase of copper concentration in liver parenchyma and distinct pathological changes of laboratory data. In the remaining 6 patients no pathological change of liver morphology was demonstrated by MRI corresponding to slight histopathological changes of parenchyma and normal laboratory data. As low-intensity nodules surrounded by high intensity septa can be demonstrated in patients with marked inflammatory infiltration of liver parenchyma MRI may help to define Wilson patients with poorer prognosis. In patients with low-intensity nodules of the liver and unknown cause of liver cirrhosis laboratory data and histopathology should be checked when searching for disorders of copper metabolism. (orig.) [Deutsch] Im Rahmen einer prospektiven Studie wurde die Leber bei 16 Patienten mit klinisch gesichertem Morbus Wilson magnetresonanztomographisch untersucht. Zum Einsatz kamen T{sub 1}- und T{sub 2}-gewichtete Spin-Echo-Sequenzen vor und nach Applikation von Gd-DTPA (0,1 mmol/kg KG). Anhand der MRT-Befunde konnten zwei unterschiedliche Patientenkollektive definiert werden. 10 Patienten wiesen in der T{sub 2}-gewichteten Sequenz hypointense Regeneratknoten auf und zeigten histopathologisch ausgepraegte Befunde einer
Symmetry Relations and the Nonperturbative Form of Interactions
Institute of Scientific and Technical Information of China (English)
2001-01-01
Applying QCD to study and understand hadronic physics and nuclear physics is one of basic goals of modern nuclear physics. Developing nonperturbative approach of QCD to understand the dynamical chiral-symmetry breaking and color confinement then becomes one of our most important challenges. Besides the lattice gauge theory, the Dyson-Schwinger equation (DSE) formalism is such an appropriate nonperturbative approach. In undertaking nonperturbative studies using DSEs, we immediately have to confront the issue of what is the nonperturbative form of interactions. In recent 20 years, there have been considerable efforts to solve this open problem, however, all such attempts
Illustrated study of the semi-holographic non-perturbative framework
Banerjee, Souvik; Gaddam, Nava; Mukhopadhyay, Ayan
2017-01-01
Semi-holography has been proposed as an effective nonperturbative framework which can combine perturbative and nonperturbative effects consistently for theories like QCD. It is postulated that the strongly coupled nonperturbative sector has a holographic dual in the form of a classical gravity
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education. A John Wilson. Articles written in Resonance – Journal of Science Education. Volume 11 Issue 7 July 2006 pp 70-76 Classroom. Inverting Matrices Constructed from Roots of Unity · A John Wilson · More Details Fulltext PDF ...
Non-perturbative QCD. Renormalization, O(a)-improvement and matching to heavy quark effective theory
Energy Technology Data Exchange (ETDEWEB)
Sommer, R.
2006-11-15
We give an introduction to three topics in lattice gauge theory: I. The Schroedinger Functional and O(a) improvement. O(a) improvement has been reviewed several times. Here we focus on explaining the basic ideas in detail and then proceed directly to an overview of the literature and our personal assessment of what has been achieved and what is missing. II. The computation of the running coupling, running quark masses and the extraction of the renormalization group invariants. We focus on the basic strategy and on the large effort that has been invested in understanding the continuum limit. We point out what remains to be done. III. Non-perturbative Heavy Quark Effective Theory. Since the literature on this subject is still rather sparse, we go beyond the basic ideas and discuss in some detail how the theory works in principle and in practice. (orig.)
Non-perturbative QCD. Renormalization, O(a)-improvement and matching to heavy quark effective theory
International Nuclear Information System (INIS)
Sommer, R.
2006-11-01
We give an introduction to three topics in lattice gauge theory: I. The Schroedinger Functional and O(a) improvement. O(a) improvement has been reviewed several times. Here we focus on explaining the basic ideas in detail and then proceed directly to an overview of the literature and our personal assessment of what has been achieved and what is missing. II. The computation of the running coupling, running quark masses and the extraction of the renormalization group invariants. We focus on the basic strategy and on the large effort that has been invested in understanding the continuum limit. We point out what remains to be done. III. Non-perturbative Heavy Quark Effective Theory. Since the literature on this subject is still rather sparse, we go beyond the basic ideas and discuss in some detail how the theory works in principle and in practice. (orig.)
Non-Perturbative Quantum Geometry III
Krefl, Daniel
2016-08-02
The Nekrasov-Shatashvili limit of the refined topological string on toric Calabi-Yau manifolds and the resulting quantum geometry is studied from a non-perturbative perspective. The quantum differential and thus the quantum periods exhibit Stockes phenomena over the combined string coupling and quantized Kaehler moduli space. We outline that the underlying formalism of exact quantization is generally applicable to points in moduli space featuring massless hypermultiplets, leading to non-perturbative band splitting. Our prime example is local P1xP1 near a conifold point in moduli space. In particular, we will present numerical evidence that in a Stockes chamber of interest the string based quantum geometry reproduces the non-perturbative corrections for the Nekrasov-Shatashvili limit of 4d supersymmetric SU(2) gauge theory at strong coupling found in the previous part of this series. A preliminary discussion of local P2 near the conifold point in moduli space is also provided.
U-duality multiplets and nonperturbative superstring states
International Nuclear Information System (INIS)
Bars, I.; Yankielowicz, S.
1996-01-01
We employ an algebraic approach for unifying perturbative and nonperturbative superstring states on an equal footing, in the form of U-duality multiplets, at all excited string levels. In compactified type-IIA supertring theory we present evidence that the multiplet is labeled by two spaces, open-quote open-quote index close-quote close-quote space and open-quote open-quote base close-quote close-quote space, on which U acts without mixing them. Both spaces are nonperturbative extensions of similar spaces that label perturbative T-duality multiplets. Base space consists of all the central charges of the 11D SUSY algebra, while index space corresponds to representations of the maximal compact subgroup K improper-subset U. This structure predicts the quantum numbers of the nonperturbative states. We also discuss whether and how U multiplets may coexist with 11-dimensional multiplets that are associated with an additional nonperturbative 11D structure that seems to be lurking behind in the underlying theory. copyright 1996 The American Physical Society
Decays of mesons with charm quarks on the lattice
International Nuclear Information System (INIS)
Ali Khan, A.; Braun, V.; Burch, T.; Goeckeler, M.; Schaefer, A.; Schierholz, G.
2007-10-01
We investigate mesons containing charm quarks on fine lattices with a -1 ∝ 5 GeV. The quenched approximation is employed using theWilson gauge action at β = 6.6 and nonperturbatively O(a) improvedWilson quarks. We present results for decay constants using various interpolating fields and give preliminary results for form factors of semileptonic decays of D s mesons to light pseudoscalar mesons. (orig.)
Determination of c{sub sw} in N{sub f}=3+1 lattice QCD with massive Wilson fermions
Energy Technology Data Exchange (ETDEWEB)
Stollenwerk, Felix
2017-02-07
In order to obtain sensible results from Lattice QCD that may be compared with experiment, extrapolation to the continuum is crucial. The well-established Symanzik improvement program systematically reduces the order of cutoff effects, allowing for better control of the aforementioned errors, as well as larger and thus more affordable lattice spacings. Applied to the Wilson fermion action, it entails the addition of the Sheikholeslami-Wohlert term with the O(a) improvement coefficient c{sub sw}. In this work, a strategy is developed for the non-perturbative determination of c{sub sw} in the theory with N{sub f}=3+1 massive sea quarks. It is embedded in a general, mass-dependent renormalization and improvement scheme, for which we lay the foundations. The improvement condition, formulated by means of the PCAC relation in the Schroedinger Functional, is imposed along a line of constant physics that is designed to be close to the physical mass of the charm quark. The aim of this rather elaborate approach is to avoid large, mass-dependent O(a{sup 2}) effects in future large volume simulations with four dynamical quark species. The numerical results are worked out using the tree-level improved Luescher-Weisz gauge action. Since the gradient flow coupling is employed in the definition of the line of constant physics, its interdependence with the topological charge in regard to critical slowing down and topology freezing is investigated in a supplemental study.
A note on nonperturbative renormalization of effective field theory
Energy Technology Data Exchange (ETDEWEB)
Yang Jifeng [Department of Physics, East China Normal University, Shanghai 200062 (China)
2009-08-28
Within the realm of contact potentials, the key structures intrinsic of nonperturbative renormalization of T-matrices are unraveled using rigorous solutions and an inverse form of the algebraic Lippmann-Schwinger equation. The intrinsic mismatches between effective field theory power counting and nonperturbative divergence structures are shown for the first time to preclude the conventional counterterm algorithm from working in the renormalization of EFT for NN scattering in nonperturbative regimes.
A note on nonperturbative renormalization of effective field theory
International Nuclear Information System (INIS)
Yang Jifeng
2009-01-01
Within the realm of contact potentials, the key structures intrinsic of nonperturbative renormalization of T-matrices are unraveled using rigorous solutions and an inverse form of the algebraic Lippmann-Schwinger equation. The intrinsic mismatches between effective field theory power counting and nonperturbative divergence structures are shown for the first time to preclude the conventional counterterm algorithm from working in the renormalization of EFT for NN scattering in nonperturbative regimes.
The Wilson loop and some applications
International Nuclear Information System (INIS)
Bezerra, V.B.
1983-01-01
A simple relation between the classical Wilson loop and the angular deviation in the parallel shift is found. An example of potential which given field copies and which give the same classical Wilson loop for a given trajectory is exchibited. Afterwards, the asymptotic behaviour of the Wilson loop for the BPST instanton and meron is discussed. Using the dimensional regularization technique to calculate the second order term of Quantum Wilson loop, the influence of geometrical factors for the residue in the polo due to contact points, cusp and intersections, in function of the upsilon dimension of the space-time is investigated. Finally, the charge renormalization in Quantum Electrodynamics using Quantum Wilson loop is calculated. (L.C.) [pt
The Wilson loop and some applications
International Nuclear Information System (INIS)
Bezerra, V.B.
1983-04-01
A simple relation between the classical Wilson loop and the angular deviation in the parallel displacement is found. An example of potentials which give field copies and which suplly the same classical Wilson loop for a particular trajectory is exhibited. The asymptotic behaviour of the Wilson loop for the BPST instanton and the meron, is discussed. By using the dimensional regularization technique to calculate the second order term of the quantum Wilson loop, the influence of geometrical factors for the residue in the pole due to contact points, cuspides and intersections, in function of the space-time ν, is investigated. Charge renormalization in Quantum electrodynamics is finally calculated by using the quantum Wilson loop. (L.C.) [pt
Nonperturbative volume reduction of large-N QCD with adjoint fermions
International Nuclear Information System (INIS)
Bringoltz, Barak; Sharpe, Stephen R.
2009-01-01
We use nonperturbative lattice techniques to study the volume-reduced 'Eguchi-Kawai' version of four-dimensional large-N QCD with a single adjoint Dirac fermion. We explore the phase diagram of this single-site theory in the space of quark mass and gauge coupling using Wilson fermions for a number of colors in the range 8≤N≤15. Our evidence suggests that these values of N are large enough to determine the nature of the phase diagram for N→∞. We identify the region in the parameter space where the (Z N ) 4 center symmetry is intact. According to previous theoretical work using the orbifolding paradigm, and assuming that translation invariance is not spontaneously broken in the infinite-volume theory, in this region volume reduction holds: the single-site and infinite-volume theories become equivalent when N→∞. We find strong evidence that this region includes both light and heavy quarks (with masses that are at the cutoff scale), and our results are consistent with this region extending toward the continuum limit. We also compare the action density and the eigenvalue density of the overlap Dirac operator in the fundamental representation with those obtained in large-N pure-gauge theory.
Non-perturbative QCD and hadron physics
International Nuclear Information System (INIS)
Cobos-Martínez, J J
2016-01-01
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. (paper)
[Jacqueline Wilson. Tracy Beakeri sari] / Krista Kivisalu
Kivisalu, Krista, 1968-
2016-01-01
Tutvustus: Wilson, Jacqueline. Tracy Beakeri lugu. [Tallinn] : Pegasus, 2015 ; Wilson, Jacqueline. Pühadeüllatus. [Tallinn] : Pegasus, c2015 ; Wilson, Jacqueline. Julgusmäng. [Tallinn] : Pegasus, c2015
Non-perturbative effects and the refined topological string
Energy Technology Data Exchange (ETDEWEB)
Hatsuda, Yasuyuki [DESY Hamburg (Germany). Theory Group; Tokyo Institute of Technology (Japan). Dept. of Physics; Marino, Marcos [Geneve Univ. (Switzerland). Dept. de Physique Theorique et Section de Mathematiques; Moriyama, Sanefumi [Nagoya Univ. (Japan). Kobayashi Maskawa Inst.; Nagoya Univ. (Japan). Graduate School of Mathematics; Okuyama, Kazumi [Shinshu Univ., Matsumoto, Nagano (Japan). Dept. of Physics
2013-06-15
The partition function of ABJM theory on the three-sphere has non-perturbative corrections due to membrane instantons in the M-theory dual. We show that the full series of membrane instanton corrections is completely determined by the refined topological string on the Calabi-Yau manifold known as local P{sup 1} x P{sup 1}, in the Nekrasov-Shatashvili limit. Our result can be interpreted as a first-principles derivation of the full series of non-perturbative effects for the closed topological string on this Calabi-Yau background. Based on this, we make a proposal for the non-perturbative free energy of topological strings on general, local Calabi-Yau manifolds.
Nonperturbative quantum gravity
International Nuclear Information System (INIS)
Ambjørn, J.; Görlich, A.; Jurkiewicz, J.; Loll, R.
2012-01-01
Asymptotic safety describes a scenario in which general relativity can be quantized as a conventional field theory, despite being nonrenormalizable when expanding it around a fixed background geometry. It is formulated in the framework of the Wilsonian renormalization group and relies crucially on the existence of an ultraviolet fixed point, for which evidence has been found using renormalization group equations in the continuum. “Causal Dynamical Triangulations” (CDT) is a concrete research program to obtain a nonperturbative quantum field theory of gravity via a lattice regularization, and represented as a sum over spacetime histories. In the Wilsonian spirit one can use this formulation to try to locate fixed points of the lattice theory and thereby provide independent, nonperturbative evidence for the existence of a UV fixed point. We describe the formalism of CDT, its phase diagram, possible fixed points and the “quantum geometries” which emerge in the different phases. We also argue that the formalism may be able to describe a more general class of Hořava–Lifshitz gravitational models.
International Nuclear Information System (INIS)
Brzoska, A.M.; Lenz, F.; Thies, M.; Negele, J.W.
2005-01-01
A phenomenological analysis of the distribution of Wilson loops in SU(2) Yang-Mills theory is presented in which Wilson loop distributions are described as the result of a diffusion process on the group manifold. It is shown that, in the absence of forces, diffusion implies Casimir scaling and, conversely, exact Casimir scaling implies free diffusion. Screening processes occur if diffusion takes place in a potential. The crucial distinction between screening of fundamental and adjoint loops is formulated as a symmetry property related to the center symmetry of the underlying gauge theory. The results are expressed in terms of an effective Wilson loop action and compared with various limits of SU(2) Yang-Mills theory
Non-perturbative effective interactions in the standard model
Energy Technology Data Exchange (ETDEWEB)
Arbuzov, Boris A. [Moscow Lomonosov State Univ. (Russian Federation). Skobeltsyn Inst. of Nuclear Physics
2014-07-01
This monograph is devoted to the nonperturbative dynamics in the Standard Model (SM), the basic theory of allfundamental interactions in natureexcept gravity. The Standard Model is divided into two parts: the quantum chromodynamics (QCD) and the electro-weak theory (EWT) are well-defined renormalizable theories in which the perturbation theory is valid. However, for the adequate description of the real physics nonperturbative effects are inevitable. This book describes how these nonperturbative effects may be obtained in the framework of spontaneous generation of effective interactions. The well-known example of such effective interaction is provided by the famous Nambu-Jona-Lasinio effective interaction. Also a spontaneous generation of this interaction in the framework of QCD is described and applied to the method for other effective interactions in QCD and EWT. The method is based on N.N. Bogolyubov's conception of compensation equations. As a result we then describe the principal features of the Standard Model, e.g. Higgs sector, and significant nonperturbative effects including recent results obtained at LHC and TEVATRON.
Non-perturbative versus perturbative renormalization of lattice operators
International Nuclear Information System (INIS)
Goeckeler, M.; Technische Hochschule Aachen; Horsley, R.; Ilgenfritz, E.M.; Oelrich, H.; Forschungszentrum Juelich GmbH; Schierholz, G.; Forschungszentrum Juelich GmbH; Perlt, H.; Schiller, A.; Rakow, P.
1995-09-01
Our objective is to compute the moments of the deep-inelastic structure functions of the nucleon on the lattice. A major source of uncertainty is the renormalization of the lattice operators that enter the calculation. In this talk we compare the renormalization constants of the most relevant twist-two bilinear quark operators which we have computed non-perturbatively and perturbatively to one loop order. Furthermore, we discuss the use of tadpole improved perturbation theory. (orig.)
A non-perturbative argument for the non-abelian Higgs mechanism
International Nuclear Information System (INIS)
De Palma, G.; Strocchi, F.
2013-01-01
The evasion of massless Goldstone bosons by the non-abelian Higgs mechanism is proved by a non-perturbative argument in the local BRST gauge. -- Highlights: •The perturbative explanation of the Higgs mechanism (HM) is not under mathematical control. •We offer a non-perturbative proof of the absence of Goldstone bosons from the non-abelian HM. •Our non-perturbative proof in the BRST gauge avoids a mean field ansatz and expansion
A non-perturbative argument for the non-abelian Higgs mechanism
Energy Technology Data Exchange (ETDEWEB)
De Palma, G. [Scuola Normale Superiore, Pisa (Italy); INFN, Sezione di Pisa, Pisa (Italy); Strocchi, F., E-mail: franco.strocchi@sns.it [INFN, Sezione di Pisa, Pisa (Italy)
2013-09-15
The evasion of massless Goldstone bosons by the non-abelian Higgs mechanism is proved by a non-perturbative argument in the local BRST gauge. -- Highlights: •The perturbative explanation of the Higgs mechanism (HM) is not under mathematical control. •We offer a non-perturbative proof of the absence of Goldstone bosons from the non-abelian HM. •Our non-perturbative proof in the BRST gauge avoids a mean field ansatz and expansion.
Energy Technology Data Exchange (ETDEWEB)
Anon.
1994-06-15
On March 4, an international symposium and tribute was held at Fermilab in honour of the Laboratory's founding director Robert Rathbun Wilson on the occasion of his 80th birthday. The symposium - 'Celebrating an Era of Courage and Creativity' - featured talks and reflections by many of Wilson's colleagues and friends including Fermilab Director John Peoples and Director Emeritus Leon Lederman.
International Nuclear Information System (INIS)
Anon.
1994-01-01
On March 4, an international symposium and tribute was held at Fermilab in honour of the Laboratory's founding director Robert Rathbun Wilson on the occasion of his 80th birthday. The symposium - 'Celebrating an Era of Courage and Creativity' - featured talks and reflections by many of Wilson's colleagues and friends including Fermilab Director John Peoples and Director Emeritus Leon Lederman
N = 1 SU(2) supersymmetric Yang-Mills theory on the lattice with light dynamical Wilson gluinos
International Nuclear Information System (INIS)
Demmouche, Kamel
2009-01-01
The supersymmetric Yang-Mills (SYM) theory with one supercharge (N=1) and one additional Majorana matter-field represents the simplest model of supersymmetric gauge theory. Similarly to QCD, this model includes gauge fields, gluons, with color gauge group SU(N c ) and fermion fields, describing the gluinos. The non-perturbative dynamical features of strongly coupled supersymmetric theories are of great physical interest. For this reason, many efforts are dedicated to their formulation on the lattice. The lattice regularization provides a powerful tool to investigate non-perturbatively the phenomena occurring in SYM such as confinement and chiral symmetry breaking. In this work we perform numerical simulations of the pure SU(2) SYM theory on large lattices with small Majorana gluino masses down to about m g approx 115 MeV with lattice spacing up to a ≅0.1 fm. The gluino dynamics is simulated by the Two-Step Multi-Boson (TSMB) and the Two-Step Polynomial Hybrid Monte Carlo (TS-PHMC) algorithms. Supersymmetry (SUSY) is broken explicitly by the lattice and the Wilson term and softly by the presence of a non-vanishing gluino mass m g ≠0. However, the recovery of SUSY is expected in the infinite volume continuum limit by tuning the bare parameters to the SUSY point in the parameter space. This scenario is studied by the determination of the low-energy mass spectrum and by means of lattice SUSY Ward-Identities (WIs). (orig.)
The Universal Askey-Wilson Algebra
Directory of Open Access Journals (Sweden)
Paul Terwilliger
2011-07-01
Full Text Available In 1992 A. Zhedanov introduced the Askey-Wilson algebra AW=AW(3 and used it to describe the Askey-Wilson polynomials. In this paper we introduce a central extension Δ of AW, obtained from AW by reinterpreting certain parameters as central elements in the algebra. We call Δ the universal Askey-Wilson algebra. We give a faithful action of the modular group PSL_2(Z on Δ as a group of automorphisms. We give a linear basis for Δ. We describe the center of Δ and the 2-sided ideal Δ[Δ,Δ]Δ. We discuss how Δ is related to the q-Onsager algebra.
Distribution amplitudes of vector mesons
Energy Technology Data Exchange (ETDEWEB)
Braun, V.M. [Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Broemmel, D. [Deutsches Elektronen-Synchrotron, Hamburg (Germany); Goeckeler, M. [Regensburg Univ. (DE). Inst. fuer Theoretische Physik] (and others)
2007-11-15
Results are presented for the lowest moment of the distribution amplitude for the K{sup *} vector meson. Both longitudinal and transverse moments are investigated. We use two flavours of O(a) improved Wilson fermions, together with a non-perturbative renormalisation of the matrix element. (orig.)
An improved single-plaquette gauge action
International Nuclear Information System (INIS)
Banerjee, D.; Bögli, M.; Holland, K.; Niedermayer, F.; Pepe, M.; Wenger, University; Wiese, UniversityJ.
2016-01-01
We describe and test a nonperturbatively improved single-plaquette lattice action for 4-d SU(2) and SU(3) pure gauge theory, which suppresses large fluctuations of the plaquette, without requiring the naive continuum limit for smooth fields. We tune the action parameters based on torelon masses in moderate cubic physical volumes, and investigate the size of cut-off effects in other physical quantities, including torelon masses in asymmetric spatial volumes, the static quark potential, and gradient flow observables. In 2-d O(N) models similarly constructed nearest-neighbor actions have led to a drastic reduction of cut-off effects, down to the permille level, in a wide variety of physical quantities. In the gauge theories, we find significant reduction of lattice artifacts, and for some observables, the coarsest lattice result is very close to the continuum value. We estimate an improvement factor of 40 compared to using the Wilson gauge action to achieve the same statistical accuracy and suppression of cut-off effects.
Perturbative and nonperturbative renormalization in lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Goeckeler, M. [Regensburg Univ. (Germany). Institut fuer Theoretische Physik; Horsley, R. [University of Edinburgh (United Kingdom). School of Physics and Astronomy; Perlt, H. [Leipzig Univ. (DE). Institut fuer Theoretische Physik] (and others)
2010-03-15
We investigate the perturbative and nonperturbative renormalization of composite operators in lattice QCD restricting ourselves to operators that are bilinear in the quark fields (quark-antiquark operators). These include operators which are relevant to the calculation of moments of hadronic structure functions. The nonperturbative computations are based on Monte Carlo simulations with two flavors of clover fermions and utilize the Rome-Southampton method also known as the RI-MOM scheme. We compare the results of this approach with various estimates from lattice perturbation theory, in particular with recent two-loop calculations. (orig.)
Non-perturbative QCD Effect on K-Factor of Drell-Yan Process
International Nuclear Information System (INIS)
Hou Zhaoyu; Zhi Haisu; Chen Junxiao
2006-01-01
By using a non-perturbative quark propagator with the lowest-dimensional condensate contributions from the QCD vacuum, the non-perturbative effect to K-factor of the Drell-Yan process is numerically investigated for 12 6 C- 12 6 C collision at the center-of-mass energy (s) 1/2 = 200 GeV, 630 GeV respectively. Calculated results show that the non-perturbative QCD effect has just a weak influence on K-factor in the two cases.
On the non-perturbative effects
International Nuclear Information System (INIS)
Manjavidze, J.; Voronyuk, V.
2004-01-01
The quantum correspondence principle based on the time reversibility is adopted to take into account the non-Abelian symmetry constrains. The main properties of the new strong-coupling perturbation theory which take into account non-perturbative effects are described. (author)
Meson masses in electromagnetic fields with Wilson fermions
Bali, G. S.; Brandt, B. B.; Endrődi, G.; Gläßle, B.
2018-02-01
We determine the light meson spectrum in QCD in the presence of background magnetic fields using quenched Wilson fermions. Our continuum extrapolated results indicate a monotonous reduction of the connected neutral pion mass as the magnetic field grows. The vector meson mass is found to remain nonzero, a finding relevant for the conjectured ρ -meson condensation at strong magnetic fields. The continuum extrapolation was facilitated by adding a novel magnetic field-dependent improvement term to the additive quark mass renormalization. Without this term, sizable lattice artifacts that would deceptively indicate an unphysical rise of the connected neutral pion mass for strong magnetic fields are present. We also investigate the impact of these lattice artifacts on further observables like magnetic polarizabilities and discuss the magnetic field-induced mixing between ρ -mesons and pions. We also derive Ward-Takashi identities for QCD +QED both in the continuum formulation and for (order a -improved) Wilson fermions.
A nonperturbative solution of D=1 string theory
International Nuclear Information System (INIS)
Gross, D.J.; Miljkovic, N.
1990-01-01
We derive a nonperturbative solution of D=1 string theory, based on a double scaling limit of the one dimensional random matrix model. We derive an exact expression for the partition function in terms of the string coupling constant. The weak coupling expansion suffers from infrared divergences, which we attribute to massless tadpoles. The continuum limit seems to be well defined, however, in a strong coupling expansion. This could correspond to a different stable nonperturbative vacuum. (orig.)
Thoughts on non-perturbative thermalization and jet quenching in heavy ion collisions
International Nuclear Information System (INIS)
Kovchegov, Yuri V.
2006-01-01
We start by presenting physical arguments for the impossibility of perturbative thermalization leading to (non-viscous) Bjorken hydrodynamic description of heavy ion collisions. These arguments are complimentary to our more formal argument presented in [Yu.V. Kovchegov, hep-ph/0503038]. We argue that the success of hydrodynamic models in describing the quark-gluon system produced in heavy ion collisions could only be due to non-perturbative strong coupling effects. We continue by studying non-perturbative effects in heavy ion collisions at high energies. We model non-perturbative phenomena by an instanton ensemble. We show that non-perturbative instanton vacuum fields may significantly contribute to jet quenching in nuclear collisions. At the same time, the instanton ensemble contribution to thermalization is likely to be rather weak, leading to non-perturbative thermalization time comparable to the time of hadronization. This example illustrates that jet quenching is not necessarily a signal of a thermalized medium. Indeed, since the instanton models do not capture all the effects of QCD vacuum (e.g., they do not account for confinement), there may be other non-perturbative effects facilitating thermalization of the system
Spectrum of the Wilson Dirac operator at finite lattice spacings
DEFF Research Database (Denmark)
Akemann, G.; Damgaard, Poul Henrik; Splittorff, Kim
2011-01-01
We consider the effect of discretization errors on the microscopic spectrum of the Wilson Dirac operator using both chiral Perturbation Theory and chiral Random Matrix Theory. A graded chiral Lagrangian is used to evaluate the microscopic spectral density of the Hermitian Wilson Dirac operator...... as well as the distribution of the chirality over the real eigenvalues of the Wilson Dirac operator. It is shown that a chiral Random Matrix Theory for the Wilson Dirac operator reproduces the leading zero-momentum terms of Wilson chiral Perturbation Theory. All results are obtained for fixed index...... of the Wilson Dirac operator. The low-energy constants of Wilson chiral Perturbation theory are shown to be constrained by the Hermiticity properties of the Wilson Dirac operator....
Near BPS Wilson loop in β-deformed theories
International Nuclear Information System (INIS)
Chu, C-S; Giataganas, Dimitrios
2007-01-01
We propose a definition of the Wilson loop operator in the N = 1 β-deformed supersymmetric Yang-Mills theory. Although the operator is not BPS, it has a finite expectation value at least up to order (g 2 N) 2 . This does not happen generally for a generic non-BPS Wilson loop whose expectation value is UV divergent. For this reason we call this a near-BPS Wilson loop. We derive the general form of the boundary condition satisfied by the dual string worldsheet and find that it is deformed. Finiteness of the expectation value of the Wilson loop fixes the boundary condition to be one which is characterized by the vielbein of the deformed supergravity metric. The Wilson loop operators provide natural candidates as dual descriptions to some of the existing D-brane configurations in the Lunin-Maldacena background. We also construct the string dual configuration for a near-1/4 BPS circular Wilson loop operator. The string lies on a deformed three-sphere instead of a two-sphere as in the undeformed case. The expectation value of the Wilson loop operator is computed using the AdS/CFT correspondence and is found to be independent of the deformation. We conjecture that the exact expectation value of the Wilson loop is given by the same matrix model as in the undeformed case
Non-perturbative methods applied to multiphoton ionization
International Nuclear Information System (INIS)
Brandi, H.S.; Davidovich, L.; Zagury, N.
1982-09-01
The use of non-perturbative methods in the treatment of atomic ionization is discussed. Particular attention is given to schemes of the type proposed by Keldysh where multiphoton ionization and tunnel auto-ionization occur for high intensity fields. These methods are shown to correspond to a certain type of expansion of the T-matrix in the intra-atomic potential; in this manner a criterium concerning the range of application of these non-perturbative schemes is suggested. A brief comparison between the ionization rate of atoms in the presence of linearly and circularly polarized light is presented. (Author) [pt
Procedural learning changes in patients with Wilson's disease
Institute of Scientific and Technical Information of China (English)
Yumei Jiang; Xiang Shen; Xiaoping Wang; Wenjie Li
2011-01-01
In the present study, we compared explicit memory performance, using the Wechsler Memory Scale, and implicit memory performance, using the Nissen software version of the serial reaction time task, in patients with Wilson's disease to normal controls. The Wilson's disease patients exhibited deficits in explicit memory tasks, such as figure recall and understanding memory. Moreover, the Wilson's disease patients exhibited deficits in implicit memory tasks, including significantly prolonged response times. These findings indicate that Wilson's disease patients have explicit and implicit partial memory impairments.
Non-perturbative heavy quark effective theory. Introduction and status
International Nuclear Information System (INIS)
Sommer, Rainer; Humboldt-Universitaet, Berlin
2015-01-01
We give an introduction to Heavy Quark Effective Theory (HQET). Our emphasis is on its formulation non-perturbative in the strong coupling, including the non-perturbative determination of the parameters in the HQET Lagrangian. In a second part we review the present status of HQET on the lattice, largely based on work of the ALPHA collaboration in the last few years. We finally discuss opportunities and challenges.
Non-perturbative effective interactions in the standard model
Arbuzov, Boris A
2014-01-01
This monograph is devoted to the nonperturbative dynamics in the Standard Model (SM), the basic theory of all, but gravity, fundamental interactions in nature. The Standard Model is devided into two parts: the Quantum chromodynamics (QCD) and the Electro-weak theory (EWT) are well-defined renormalizable theories in which the perturbation theory is valid. However, for the adequate description of the real physics nonperturbative effects are inevitable. This book describes how these nonperturbative effects may be obtained in the framework of spontaneous generation of effective interactions. The well-known example of such effective interaction is provided by the famous Nambu--Jona-Lasinio effective interaction. Also a spontaneous generation of this interaction in the framework of QCD is described and applied to the method for other effective interactions in QCD and EWT. The method is based on N.N. Bogoliubov conception of compensation equations. As a result we then describe the principle feathures of the Standard...
Partially quenched lattice QCD with two degenerate dynamical light Wilson quarks
International Nuclear Information System (INIS)
De, Asit K.; Harindranath, A.; Maiti, Jyotirmoy
2006-01-01
We present our results of numerical studies of partially quenched latticed QCD with two degenerate flavors of dynamical quarks. Gauge configurations are generated with Wilson gauge action and tadpole improved Wilson fermions at β = 5.6 and K sea = 0.155, 0.156, 0.157 and 0.158. Suitably smeared gauge configurations are used to calculate the static interquark potential in order to set the physical scale. Mesonic propagators are calculated at above mentioned four different values of K val for each K sea . We present results for pion and rho masses. (author)
Non-perturbative materialization of ghosts
International Nuclear Information System (INIS)
Emparan, Roberto; Garriga, Jaume
2006-01-01
In theories with a hidden ghost sector that couples to visible matter through gravity only, empty space can decay into ghosts and ordinary matter by graviton exchange. Perturbatively, such processes can be very slow provided that the gravity sector violates Lorentz invariance above some cut-off scale. Here, we investigate non-perturbative decay processes involving ghosts, such as the spontaneous creation of self-gravitating lumps of ghost matter, as well as pairs of Bondi dipoles (i.e. lumps of ghost matter chasing after positive energy objects). We find the corresponding instantons and calculate their Euclidean action. In some cases, the instantons induce topology change or have negative Euclidean action. To shed some light on the meaning of such peculiarities, we also consider the nucleation of concentrical domain walls of ordinary and ghost matter, where the Euclidean calculation can be compared with the canonical (Lorentzian) description of tunneling. We conclude that non-perturbative ghost nucleation processes can be safely suppressed in phenomenological scenarios
Compact lattice QED with Wilson fermions
International Nuclear Information System (INIS)
Hoferichter, A.
1994-08-01
We study the phase structure and the chiral limit of 4d compact lattice QED with Wilson fermions (both dynamical and quenched). We use the standard Wilson gauge action and also a modified one suppressing lattice artifacts. Different techniques and observables to locate the chiral limit are discussed. (orig.)
Clinical investigation in Wilson's disease
International Nuclear Information System (INIS)
Mizutani, Naoki; Maehara, Mitsuo; Negoro, Tamiko; Watanabe, Kazuyoshi
1983-01-01
Wilson's disease of cerebral type with a chief complaint of tremor occurred in 3 brothers and sisters of a certain family line. Treatment with D-penicillamine produced remarkable clinical improvement as shown by the disappearance of tremor and Kayser-Fleischer ring. Cranial CT scans made before the treatment revealed abnormal findings such as low density areas in the (bilateral) thalamus and the lenticular nucleus, atrophy of the cerebral cortex, and enlargement of the ventricles. After the treatment, cranial CT revealed that the low density areas in the thalamus and the lenticular nucleus disappeared corresponding to the clinical improvement. However, the atrophy of the cerebral cortex and the enlargement of the ventricles were not ameliorated. (Ueda, J.)
Non-perturbative effective potential: Lower bounds on the Higgs mass and dynamical applications
International Nuclear Information System (INIS)
Faivre, H.
2006-01-01
The purpose of this work was to assess the benefits of using non-perturbative methods to phenomenological issues in field theory. The exact equations of the Wilson renormalization group (RG) and the effective action have been used, we have computed the energy gap between the first 2 levels in double-well potential. We get a very good agreement with exact solutions inferring from the numerical solving of the Schroedinger equation. RG equations lead to a convex effective potential that is consistent with theory. We have considered the Higgs sector of the standard model. It is commonly acknowledged that the Yukawa coupling between the top quark and the Higgs boson generates the instability of the electroweak vacuum at high energy. We show that this instability does not exist, it is a mere consequence of the extrapolation of the RG equations beyond their validity range. We have also used the effective potential for the description of the time history of the mean value of the quantum field. We have defined the conditions under which the dynamics of the mean value can be described in the local potential approximation by classical equations of motion in which the effective potential replaces the classical potential. (A.C.)
Renormalisaton of composite operators in lattice QCD. Perturbative versus nonperturbative
Energy Technology Data Exchange (ETDEWEB)
Goeckeler, M.; Nakamura, Y. [Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Horsley, R. [Edinburgh Univ. (GB). School of Physics and Astronomy] (and others)
2010-07-01
The perturbative and nonperturbative renormalisation of quark-antiquark operators in lattice QCD with two flavours of clover fermions is investigated within the research programme of the QCDSF collaboration. Operators with up to three derivatives are considered. The nonperturbative results based on the RI-MOM scheme are compared with estimates from one- and two-loop lattice perturbation theory. (orig.)
Wilson lines in quantum field theory
Energy Technology Data Exchange (ETDEWEB)
Cherednikov, Igor Olegovich [Antwerpen Univ., Antwerp (Belgium). Fysica Dept.; Joint Institute of Nuclear Research, Moscow (Russian Federation). Bogoliubov Lab. of Theoretical Physics; Mertens, Tom; Veken, Frederik F. van der [Antwerpen Univ., Antwerp (Belgium). Fysica Dept.
2014-07-01
Wilson lines (also known as gauge links or eikonal lines) can be introduced in any gauge field theory. Although the concept of the Wilson exponentials finds an enormously wide range of applications in a variety of branches of modern quantum field theory, from condensed matter and lattice simulations to quantum chromodynamics, high-energy effective theories and gravity, there are surprisingly few books or textbooks on the market which contain comprehensive pedagogical introduction and consecutive exposition of the subject. The objective of this book is to get the potential reader acquainted with theoretical and mathematical foundations of the concept of the Wilson loops in the context of modern quantum field theory, to teach him/her to perform independently some elementary calculations with Wilson lines, and to familiarize him/her with the recent development of the subject in different important areas of research. The target audience of the book consists of graduate and postgraduate students working in various areas of quantum field theory, as well as researchers from other fields.
Wilson lines in quantum field theory
International Nuclear Information System (INIS)
Cherednikov, Igor Olegovich; Joint Institute of Nuclear Research, Moscow; Mertens, Tom; Veken, Frederik F. van der
2014-01-01
Wilson lines (also known as gauge links or eikonal lines) can be introduced in any gauge field theory. Although the concept of the Wilson exponentials finds an enormously wide range of applications in a variety of branches of modern quantum field theory, from condensed matter and lattice simulations to quantum chromodynamics, high-energy effective theories and gravity, there are surprisingly few books or textbooks on the market which contain comprehensive pedagogical introduction and consecutive exposition of the subject. The objective of this book is to get the potential reader acquainted with theoretical and mathematical foundations of the concept of the Wilson loops in the context of modern quantum field theory, to teach him/her to perform independently some elementary calculations with Wilson lines, and to familiarize him/her with the recent development of the subject in different important areas of research. The target audience of the book consists of graduate and postgraduate students working in various areas of quantum field theory, as well as researchers from other fields.
Duality covariant type IIB supersymmetry and nonperturbative consequences
Bars, Itzhak
1997-01-01
Type-IIB supersymmetric theories have an SL(2,Z) invariance, known as U-duality, which controls the non-perturbative behavior of the theory. Under SL(2,Z) the supercharges are doublets, implying that the bosonic charges would be singlets or triplets. However, among the bosonic charges there are doublet strings and doublet fivebranes which are in conflict with the doublet property of the supercharges. It is shown that the conflict is resolved by structure constants that depend on moduli, such as the tau parameter, which transform under the same SL(2,Z). The resulting superalgebra encodes the non-perturbative duality properties of the theory and is valid for any value of the string coupling constant. The usefulness of the formalism is illustrated by applying it to purely algebraic computations of the tension of (p,q) strings, and the mass and entropy of extremal blackholes constructed from D-1-branes and D-5-branes. In the latter case the non-perturbative coupling dependence of the BPS mass and metric is comput...
Non-Perturbative Renormalization
Mastropietro, Vieri
2008-01-01
The notion of renormalization is at the core of several spectacular achievements of contemporary physics, and in the last years powerful techniques have been developed allowing to put renormalization on a firm mathematical basis. This book provides a self-consistent and accessible introduction to the sophisticated tools used in the modern theory of non-perturbative renormalization, allowing an unified and rigorous treatment of Quantum Field Theory, Statistical Physics and Condensed Matter models. In particular the first part of this book is devoted to Constructive Quantum Field Theory, providi
Wilson lines in quantum field theory
Cherednikov, Igor O; Veken, Frederik F van der
2014-01-01
The objective of this book is to get the reader acquainted with theoretical and mathematical foundations of the concept of Wilson loops in the context of modern quantum field theory. It teaches how to perform independently with some elementary calculations on Wilson lines, and shows the recent development of the subject in different important areas of research.
Interacting open Wilson lines from noncommutative field theories
International Nuclear Information System (INIS)
Kiem, Youngjai; Lee, Sangmin; Rey, Soo-Jong; Sato, Haru-Tada
2002-01-01
In noncommutative field theories, it is known that the one-loop effective action describes the propagation of noninteracting open Wilson lines, obeying the flying dipole's relation. We show that the two-loop effective action describes the cubic interaction among 'closed string' states created by open Wilson line operators. Taking d-dimensional λ[Φ 3 ] * theory as the simplest setup, we compute the nonplanar contribution at a low-energy and large noncommutativity limit. We find that the contribution is expressible in a remarkably simple cubic interaction involving scalar open Wilson lines only and nothing else. We show that the interaction is purely geometrical and noncommutative in nature, depending only on the size of each open Wilson line
Non-perturbative inputs for gluon distributions in the hadrons
International Nuclear Information System (INIS)
Ermolaev, B.I.; Troyan, S.I.
2017-01-01
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. (orig.)
Non-perturbative inputs for gluon distributions in the hadrons
Energy Technology Data Exchange (ETDEWEB)
Ermolaev, B.I. [Ioffe Physico-Technical Institute, Saint Petersburg (Russian Federation); Troyan, S.I. [St. Petersburg Institute of Nuclear Physics, Gatchina (Russian Federation)
2017-03-15
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{sub T}-and collinear factorizations. (orig.)
Conformal anomaly of super Wilson loop
Energy Technology Data Exchange (ETDEWEB)
Belitsky, A.V., E-mail: andrei.belitsky@asu.edu [Department of Physics, Arizona State University, Tempe, AZ 85287-1504 (United States)
2012-09-11
Classically supersymmetric Wilson loop on a null polygonal contour possesses all symmetries required to match it onto non-MHV amplitudes in maximally supersymmetric Yang-Mills theory. However, to define it quantum mechanically, one is forced to regularize it since perturbative loop diagrams are not well defined due to presence of ultraviolet divergences stemming from integration in the vicinity of the cusps. A regularization that is adopted by practitioners by allowing one to use spinor helicity formalism, on the one hand, and systematically go to higher orders of perturbation theory is based on a version of dimensional regularization, known as Four-Dimensional Helicity scheme. Recently it was demonstrated that its use for the super Wilson loop at one loop breaks both conformal symmetry and Poincare supersymmetry. Presently, we exhibit the origin for these effects and demonstrate how one can undo this breaking. The phenomenon is alike the one emerging in renormalization group mixing of conformal operators in conformal theories when one uses dimensional regularization. The rotation matrix to the diagonal basis is found by means of computing the anomaly in the Ward identity for the conformal boost. Presently, we apply this ideology to the super Wilson loop. We compute the one-loop conformal anomaly for the super Wilson loop and find that the anomaly depends on its Grassmann coordinates. By subtracting this anomalous contribution from the super Wilson loop we restore its interpretation as a dual description for reduced non-MHV amplitudes which are expressed in terms of superconformal invariants.
Non-perturbative Heavy Quark Effective Theory
DEFF Research Database (Denmark)
Della Morte, Michele; Heitger, Jochen; Simma, Hubert
2015-01-01
We review a lattice strategy how to non-perturbatively determine the coefficients in the HQET expansion of all components of the heavy-light axial and vector currents, including 1/m_h-corrections. We also discuss recent preliminary results on the form factors parameterizing semi-leptonic B...
Energy Technology Data Exchange (ETDEWEB)
Lopez, J. Gonzalez [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Jansen, K. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Renner, D.B. [Jefferson Lab, Newport News, VA (United States); Shindler, A. [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik
2012-08-23
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 nonperturbative regimes, and for a range of lattice spacings. We also check that the correct boundary conditions and symmetries are restored in the continuum limit. (orig.)
International Nuclear Information System (INIS)
Lopez, J. Gonzalez; Jansen, K.; Renner, D.B.; Shindler, A.
2012-01-01
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 nonperturbative regimes, and for a range of lattice spacings. We also check that the correct boundary conditions and symmetries are restored in the continuum limit. (orig.)
Non-perturbative quark mass renormalization
Capitani, S.; Luescher, M.; Sint, S.; Sommer, R.; Weisz, P.; Wittig, H.
1998-01-01
We show that the renormalization factor relating the renormalization group invariant quark masses to the bare quark masses computed in lattice QCD can be determined non-perturbatively. The calculation is based on an extension of a finite-size technique previously employed to compute the running coupling in quenched QCD. As a by-product we obtain the $\\Lambda$--parameter in this theory with completely controlled errors.
A nonperturbative proof of Dijkgraaf-Vafa conjecture
International Nuclear Information System (INIS)
Terashima, Seiji
2016-01-01
In this note we exactly compute the gaugino condensation of an arbitrary four dimensional N=1 supersymmetric gauge theory in confining phase, using the localization technique. This result gives a nonperturbative proof of the Dijkgraaf-Vafa conjecture.
Ab initio approach to the non-perturbative scalar Yukawa model
Li, YangDepartment of Physics and Astronomy, Iowa State University, Ames, IA, 50011, USA; Karmanov, V.A.(Lebedev Physical Institute, Leninsky Prospekt 53, Moscow, 119991, Russia); Maris, P.(Department of Physics and Astronomy, Iowa State University, Ames, IA, 50011, USA); Vary, J.P.(Department of Physics and Astronomy, Iowa State University, Ames, IA, 50011, USA)
2015-01-01
We report on the first non-perturbative calculation of the scalar Yukawa model in the single-nucleon sector up to four-body Fock sector truncation (one "scalar nucleon" and three "scalar pions"). The light-front Hamiltonian approach with a systematic non-perturbative renormalization is applied. We study the $n$-body norms and the electromagnetic form factor. We find that the one- and two-body contributions dominate up to coupling $\\alpha \\approx 1.7$. As we approach the coupling $\\alpha \\appr...
Monte Carlo calculation with unquenched Wilson-Fermions
International Nuclear Information System (INIS)
Montvay, I.
1984-01-01
A Monte Carlo updating procedure taking into account the virtual quark loops is described. It is based on high order hopping parameter expansion of the quark determinant for Wilson-fermions. In a first test run Wilson-loop expectation values are measured on 6 4 lattice at β=5.70 using 16sup(th) order hopping parameter expansion for the quark determinant. (orig.)
Non-Perturbative Formulation of Time-Dependent String Solutions
Alexandre, J; Mavromatos, Nikolaos E; Alexandre, Jean; Ellis, John; Mavromatos, Nikolaos E.
2006-01-01
We formulate here a new world-sheet renormalization-group technique for the bosonic string, which is non-perturbative in the Regge slope alpha' and based on a functional method for controlling the quantum fluctuations, whose magnitudes are scaled by the value of alpha'. Using this technique we exhibit, in addition to the well-known linear-dilaton cosmology, a new, non-perturbative time-dependent background solution. Using the reparametrization invariance of the string S-matrix, we demonstrate that this solution is conformally invariant to alpha', and we give a heuristic inductive argument that conformal invariance can be maintained to all orders in alpha'. This new time-dependent string solution may be applicable to primordial cosmology or to the exit from linear-dilaton cosmology at large times.
Importance of Nonperturbative QCD Parameters for Bottom Mesons
Directory of Open Access Journals (Sweden)
A. Upadhyay
2014-01-01
Full Text Available The importance of nonperturbative quantum chromodynamics (QCD parameters is discussed in context to the predicting power for bottom meson masses and isospin splitting. In the framework of heavy quark effective theory, the work presented here focuses on the different allowed values of the two nonperturbative QCD parameters used in heavy quark effective theory formula, and using the best fitted parameter, masses of the excited bottom meson states in jp=1/2+ doublet in strange and nonstrange sectors are calculated here. The calculated masses are found to be matching well with experiments and other phenomenological models. The mass splitting and hyperfine splitting have also been analyzed for both strange and nonstrange heavy mesons with respect to spin and flavor symmetries.
On Wilson bases in $L^2(\\mathbb{R}^d)$
DEFF Research Database (Denmark)
Bownik, Marcin; Sielemann Jakobsen, Mads; Lemvig, Jakob
2017-01-01
A Wilson system is a collection of finite linear combinations of time frequency shifts of a square integrable function. It is well known that, starting from a tight Gabor frame for $L^{2}(\\mathbb{R})$ with redundancy 2, one can construct an orthonormal Wilson basis for $L^2(\\mathbb{R})$ whose...... of redundancy $2^k$, where $k=1, 2, \\hdots, d$. These results generalize most of the known results about the existence of orthonormal Wilson bases....
Wilson's Disease Association International
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Wilson flow and scale setting from lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Bornyakov, V.G. [Institute for High Energy Physics, Protvino (Russian Federation); Institute of Theoretical and Experimental Physics, Moscow (Russian Federation); Far Eastern Federal Univ., Vladivostok (Russian Federation). School of Biomedicine; Horsley, R. [Edinburgh Univ. (United Kingdom). School of Physics and Astronomy; Hudspith, R. [York Univ., Toronto, ON (Canada). Dept. of Mathematics and Statistics; Collaboration: QCDSF-UKQCD Collaboration; and others
2015-08-15
We give a determination of the phenomenological value of the Wilson (or gradient) flow scales t{sub 0} and w{sub 0} for 2+1 flavours of dynamical quarks. The simulations are performed keeping the average quark mass constant, which allows the approach to the physical point to be made in a controlled manner. O(a) improved clover fermions are used and together with four lattice spacings this allows the continuum extrapolation to be taken.
Controlling quark mass determinations non-perturbatively in three-flavour QCD
Campos, Isabel
2017-01-01
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 MS-bar 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.
Hepatocellular Carcinoma: An Unusual Complication of Longstanding Wilson Disease.
Gunjan, Deepak; Shalimar; Nadda, Neeti; Kedia, Saurabh; Nayak, Baibaswata; Paul, Shashi B; Gamanagatti, Shivanand Ramachandra; Acharya, Subrat K
2017-06-01
Wilson disease is caused by the accumulation of copper in the liver, brain or other organs, due to the mutation in ATP7B gene, which encodes protein that helps in excretion of copper in the bile canaliculus. Clinical presentation varies from asymptomatic elevation of transaminases to cirrhosis with decompensation. Hepatocellular carcinoma is a known complication of cirrhosis, but a rare occurrence in Wilson disease. We present a case of neurological Wilson disease, who later developed decompensated cirrhosis and hepatocellular carcinoma.
Non-perturbative computation of the strong coupling constant on the lattice
International Nuclear Information System (INIS)
Sommer, Rainer; Humboldt-Universitaet, Berlin; Wolff, Ulli
2015-01-01
We review the long term project of the ALPHA collaboration to compute in QCD the running coupling constant and quark masses at high energy scales in terms of low energy hadronic quantities. The adapted techniques required to numerically carry out the required multiscale non-perturbative calculation with our special emphasis on the control of systematic errors are summarized. The complete results in the two dynamical flavor approximation are reviewed and an outlook is given on the ongoing three flavor extension of the programme with improved target precision.
Emergent Gauge Fields and Their Nonperturbative Effects in Correlated Electrons
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
Taking Charge: Walter Sydney Adams and the Mount Wilson Observatory
Brashear, R.
2004-12-01
The growing preeminence of American observational astronomy in the first half of the 20th century is a well-known story and much credit is given to George Ellery Hale and his skill as an observatory-building entrepreneur. But a key figure who has yet to be discussed in great detail is Walter Sydney Adams (1876-1956), Hale's Assistant Director at Mount Wilson Observatory. Due to Hale's illnesses, Adams was Acting Director for much of Hale's tenure, and he became the second Director of Mount Wilson from 1923 to 1946. Behind his New England reserve Adams was instrumental in the growth of Mount Wilson and thus American astronomy in general. Adams was hand-picked by Hale to take charge of stellar spectroscopy work at Yerkes and Mount Wilson and the younger astronomer showed tremendous loyalty to Hale and Hale's vision throughout his career. As Adams assumed the leadership role at Mount Wilson he concentrated on making the observatory a place where researchers worked with great freedom but maintain a high level of cooperation. This paper will concentrate on Adams's early years and look at his growing relationship with Hale and how he came to be the central figure in the early history of Mount Wilson as both a solar and stellar observatory. His education, his years at Dartmouth and Yerkes (including his unfortunate encounter with epsilon Leonis), and his formative years on Mount Wilson are all important in learning how he shaped the direction of Mount Wilson and the development of American astronomy in the first half of the 20th century. This latter history cannot be complete until we bring Adams into better focus.
Computerized abdominal tomography in Wilson's disease
Energy Technology Data Exchange (ETDEWEB)
Tsuchikura, Keiko; Ogawa, Teruyuki; Nakajima, Akihisa; Ono, Yasuhiko
1986-05-01
Cranial and abdominal computerized tomography (CT) was performed in a 10-year-old boy with Wilson's disease complicated by liver cirrhosis. Abdominal CT showed diffuse high density areas over the whole part of the liver propably due to copper sediments, although there was no abnormal cranial CT findings. Decreased high density area of the liver was seen 60 days after the administration of D-penicillamine, suggesting the excretion of copper from the liver. Abdominal CT, as well as cranial CT, may be of help to diagnose Wilson's disease and evaluate therapeutic effects. (Namekawa, K.).
African Journals Online (AJOL)
Ebot, Wilson Atem. Vol 8-9, No 1 (1995) - Articles Language and socio-cultural change in Ejagham Abstract PDF. ISSN: 1016-0728. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use · Contact AJOL ...
Nonperturbative results for two-index conformal windows
Energy Technology Data Exchange (ETDEWEB)
Bergner, Georg [Albert Einstein Center for Fundamental Physics,Institute for Theoretical Physics, University of Bern,Sidlerstrasse 5, CH-3012 Bern (Switzerland); Ryttov, Thomas A.; Sannino, Francesco [CP-Origins and the Danish IAS, University of Southern Denmark,5230 Odense M (Denmark)
2015-12-10
Via large and small N{sub 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{sub c} is less than about six. Nevertheless useful nonperturbative 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{sub c} two-index conformal window is twice the conformal window of the adjoint representation (which can be determined at small N{sub 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{sub c}) with two and four symmetric Dirac flavors.
Nonperturbative results for two-index conformal windows
International Nuclear Information System (INIS)
Bergner, Georg; Ryttov, Thomas A.; Sannino, Francesco
2015-01-01
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 nonperturbative 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.
Families in the nonperturbative unification scheme
Energy Technology Data Exchange (ETDEWEB)
Kapetanakis, D. (National Research Centre for the Physical Sciences Democritos, Athens (Greece)); Theisen, S. (European Organization for Nuclear Research, Geneva (Switzerland)); Zoupanos, G. (Ethnikon Metsovion Polytechneion, Athens (Greece). Dept. of Physics)
1989-10-12
Within the nonperturbative unification framework of Maiani, Parisi and Petronzio, we examine the influence of the number of fermion and Higgs families, when they are grouped in representations of horizontal family groups, on the low energy couplings of the standard model. In this way we find a number of new phenomenologically acceptable solutions for the standard model's low energy couplings. (orig.).
Families in the nonperturbative unification scheme
International Nuclear Information System (INIS)
Kapetanakis, D.; Theisen, S.; Zoupanos, G.
1989-01-01
Within the nonperturbative unification framework of Maiani, Parisi and Petronzio, we examine the influence of the number of fermion and Higgs families, when they are grouped in representations of horizontal family groups, on the low energy couplings of the standard model. In this way we find a number of new phenomenologically acceptable solutions for the standard model's low energy couplings. (orig.)
Non-perturbative aspects of string theory from elliptic curves
International Nuclear Information System (INIS)
Reuter, Jonas
2015-08-01
We consider two examples for non-perturbative aspects of string theory involving elliptic curves. First, we discuss F-theory on genus-one fibered Calabi-Yau manifolds with the fiber being a hypersurface in a toric fano variety. We discuss in detail the fiber geometry in order to find the gauge groups, matter content and Yukawa couplings of the corresponding supergravity theories for the four examples leading to gauge groups SU(3) x SU(2) x U(1), SU(4) x SU(2) x SU(2)/Z 2 , U(1) and Z 3 . The theories are connected by Higgsings on the field theory side and conifold transitions on the geometry side. We extend the discussion to the network of Higgsings relating all theories stemming from the 16 hypersurface fibrations. For the models leading to gauge groups SU(3) x SU(2) x U(1), SU(4) x SU(2) x SU(2)/Z 2 and U(1) we discuss the construction of vertical G 4 fluxes. Via the D3-brane tadpole cancelation condition we can restrict the minimal number of families in the first two of these models to be at least three. As a second example for non-perturbative aspects of string theory we discuss a proposal for a non-perturbative completion of topological string theory on local B-model geometries. We discuss in detail the computation of quantum periods for the examples of local F 1 , local F 2 and the resolution of C 3 /Z 5 . The quantum corrections are calculated order by order using second order differential operators acting on the classical periods. Using quantum geometry we calculate the refined free energies in the Nekrasov-Shatashvili limit. Finally we check the non-perturbative completion of topological string theory for the geometry of local F 2 against numerical calculations.
Woodrow Wilson National Fellowship Foundation, 2016
2016-01-01
The W. K. Kellogg Foundation's Woodrow Wilson Michigan Teaching Fellowship successfully addressed the challenge of preparing and supporting effective teachers for Michigan's high-need classrooms, while helping transform teacher education across the state for the long term. This report analyzes the efforts of the W. K. Kellogg Foundation's Woodrow…
Two-loop polygon Wilson loops in N = 4 SYM
International Nuclear Information System (INIS)
Anastasiou, C.; Brandhuber, A.; Heslop, P.; Spence, B.; Travaglini, G.; Khoze, V.V.
2009-01-01
We compute for the first time the two-loop corrections to arbitrary n-gon lightlike Wilson loops in N = 4 supersymmetric Yang-Mills theory, using efficient numerical methods. The calculation is motivated by the remarkable agreement between the finite part of planar six-point MHV amplitudes and hexagon Wilson loops which has been observed at two loops. At n = 6 we confirm that the ABDK/BDS ansatz must be corrected by adding a remainder function, which depends only on conformally invariant ratios of kinematic variables. We numerically compute remainder functions for n = 7,8 and verify dual conformal invariance. Furthermore, we study simple and multiple collinear limits of the Wilson loop remainder functions and demonstrate that they have precisely the form required by the collinear factorisation of the corresponding two-loop n-point amplitudes. The number of distinct diagram topologies contributing to the n-gon Wilson loops does not increase with n, and there is a fixed number of 'master integrals', which we have computed. Thus we have essentially computed general polygon Wilson loops, and if the correspondence with amplitudes continues to hold, all planar n-point two-loop MHV amplitudes in the N = 4 theory.
Pion parton distribution functions from lattice QCD
International Nuclear Information System (INIS)
Wetzorke, I.; Jansen, K.; Shindler, A.; Palombi, F.
2003-09-01
We report on recent results for the pion matrix element of the twist-2 operator corresponding to the average momentum of non-singlet quark densities. For the first time finite volume effects of this matrix element are investigated and come out to be surprisingly large. We use standard Wilson and non-perturbatively improved clover actions in order to control better the extrapolation to the continuum limit. Moreover, we compute, fully non-perturbatively, the renormalization group invariant matrix element, which allows a comparison with experimental results in a broad range of energy scales. Finally, we discuss the remaining uncertainties, the extrapolation to the chiral limit and the quenched approximation. (orig.)
Elliptic CY3folds and non-perturbative modular transformation
International Nuclear Information System (INIS)
Iqbal, Amer; Shabbir, Khurram
2016-01-01
We study the refined topological string partition function of a class of toric elliptically fibered Calabi-Yau threefolds. These Calabi-Yau threefolds give rise to five dimensional quiver gauge theories and are dual to configurations of M5-M2-branes. We determine the Gopakumar-Vafa invariants for these threefolds and show that the genus g free energy is given by the weight 2 g Eisenstein series. We also show that although the free energy at all genera are modular invariant, the full partition function satisfies the non-perturbative modular transformation property discussed by Lockhart and Vafa in arXiv:1210.5909 and therefore the modularity of free energy is up to non-perturbative corrections. (orig.)
Elliptic CY3folds and non-perturbative modular transformation
Energy Technology Data Exchange (ETDEWEB)
Iqbal, Amer [Government College University, Abdus Salam School of Mathematical Sciences, Lahore (Pakistan); Shabbir, Khurram [Government College University, Department of Mathematics, Lahore (Pakistan)
2016-03-15
We study the refined topological string partition function of a class of toric elliptically fibered Calabi-Yau threefolds. These Calabi-Yau threefolds give rise to five dimensional quiver gauge theories and are dual to configurations of M5-M2-branes. We determine the Gopakumar-Vafa invariants for these threefolds and show that the genus g free energy is given by the weight 2 g Eisenstein series. We also show that although the free energy at all genera are modular invariant, the full partition function satisfies the non-perturbative modular transformation property discussed by Lockhart and Vafa in arXiv:1210.5909 and therefore the modularity of free energy is up to non-perturbative corrections. (orig.)
Non-perturbative Heavy-Flavor Transport at RHIC and LHC
Energy Technology Data Exchange (ETDEWEB)
He, Min, E-mail: mhe@comp.tamu.edu; Fries, Rainer J.; Rapp, Ralf
2013-08-15
We calculate open heavy-flavor (HF) transport in relativistic heavy-ion collisions by applying a strong-coupling treatment in both macro- and microscopic dynamics (hydrodynamics and non-perturbative diffusion interactions). The hydrodynamic medium evolution is quantitatively constrained by bulk and multi-strange hadron spectra and elliptic flow. The heavy quark transport coefficient is evaluated from a non-perturbative T-matrix approach in the Quark–Gluon Plasma which, close to the critical temperature, leads to resonance formation and feeds into the recombination of heavy quarks on a hydrodynamic hypersurface. In the hadronic phase, the diffusion of HF mesons is obtained from effective hadronic theory. We compute observables at RHIC and LHC for non-photonic electrons and HF mesons, respectively.
HFE gene mutations and Wilson's disease in Sardinia.
Sorbello, Orazio; Sini, Margherita; Civolani, Alberto; Demelia, Luigi
2010-03-01
Hypocaeruloplasminaemia can lead to tissue iron storage in Wilson's disease and the possibility of iron overload in long-term overtreated patients should be considered. The HFE gene encodes a protein that is intimately involved in intestinal iron absorption. The aim of this study was to determine the prevalence of the HFE gene mutation, its role in iron metabolism of Wilson's disease patients and the interplay of therapy in copper and iron homeostasis. The records of 32 patients with Wilson's disease were reviewed for iron and copper indices, HFE gene mutations and liver biopsy. Twenty-six patients were negative for HFE gene mutations and did not present significant alterations of iron metabolism. The HFE mutation was significantly associated with increased hepatic iron content (PHFE gene wild-type. The HFE gene mutations may be an addictional factor in iron overload in Wilson's disease. Our results showed that an adjustment of dosage of drugs could prevent further iron overload induced by overtreatment only in patients HFE wild-type. 2009. Published by Elsevier Ltd.
Nonperturbative Adler-Bardeen theorem
International Nuclear Information System (INIS)
Mastropietro, Vieri
2007-01-01
The Adler-Bardeen theorem has been proven only as a statement valid at all orders in perturbation theory, without any control on the convergence of the series. In this paper we prove a nonperturbative version of the Adler-Bardeen theorem in d=2 by using recently developed technical tools in the theory of Grassmann integration. The proof is based on the assumption that the boson propagator decays fast enough for large momenta. If the boson propagator does not decay, as for Thirring contact interactions, the anomaly in the WI (Ward Identities) is renormalized by higher order contributions
The Legacy of G. Wilson Knight
Directory of Open Access Journals (Sweden)
Raw Laurence
2017-06-01
Full Text Available G. Wilson Knight (1897-1985 was one of the most influential Shakespearean critics of the mid-twentieth century. This piece surveys his work from 1930 until the early 1980s. Much affected by the First World War, he developed a style of criticism based on Christian principles of respect for other people and belief in an all-powerful God. Many of his most famous pieces (in THE WHEEL OF FIRE, for instance argue for human insignificance in an indifferent universe. It is up to all of us as individuals to develop methods of coping with this world. Wilson Knight’s ideas gained particular currency during the Second World War, when Britain’s very future seemed at risk due to the threat of Nazi invasion. Although much derided for his use of transcendent language—especially by his contemporary F. R. Leavis—Wilson Knight’s ideas seem to have acquired new significance in a globalized world, where individuals fight to main their identity in a technology-driven environment.
Ted Wilson passes on the torch
2003-01-01
As part of the Laboratory's outreach programme, the CERN Accelerator School (CAS) brings together students and experienced physicists from all over the world with the aim of promoting the understanding of accelerator physics. As head of the School for 11 years, Ted Wilson became a CERN ambassador to the outside community. He retired in March, handing over the reigns of the CAS to Daniel Brandt. Ted Wilson and his assistant, Suzanne von Wartburg, during an EPAC meeting in 1994.The accelerator schools allowed some time for relaxation in the local surrounding for students as well as for the director of CAS.As a boy, Ted Wilson could have embarked on a career in pop music rather than physics, rubbing shoulders at secondary school in Liverpool with two of the future Beatles. But prefering classical music and answering the call of science, he took the more serious of the two paths, studying physics first at Oxford University then at the Rutherford Laboratory. After a year at CERN and four years at the Rutherford La...
Solar rotation measurements at Mount Wilson. Pt. 2
International Nuclear Information System (INIS)
Labonte, B.J.; Howard, R.; Carnegie Institution of Washington, Pasadena
1981-01-01
Possible sources of systematic error in solar Doppler rotational velocities are examined. Scattered light is shown to affect the Mount Wilson solar rotation results, but this effect is not enough to bring the spectroscopic results in coincidence with the sunspot rotation. Interference fringes at the spectrograph focus at Mount Wilson have in two intervals affected the rotation results. It has been possible to correlate this error with temperature and thus correct for it. A misalignment between the entrance and exit slits is a possible source of error, but for the Mount Wilson slit configuration the amplitude of this effect is negligibly small. Rapid scanning of the solar image also produces no measurable effect. (orig.)
Conformal blocks from Wilson lines with loop corrections
Hikida, Yasuaki; Uetoko, Takahiro
2018-04-01
We compute the conformal blocks of the Virasoro minimal model or its WN extension with large central charge from Wilson line networks in a Chern-Simons theory including loop corrections. In our previous work, we offered a prescription to regularize divergences from loops attached to Wilson lines. In this paper, we generalize our method with the prescription by dealing with more general operators for N =3 and apply it to the identity W3 block. We further compute general light-light blocks and heavy-light correlators for N =2 with the Wilson line method and compare the results with known ones obtained using a different prescription. We briefly discuss general W3 blocks.
August Wilson's Presentation of Interracial Movements in 1960s
Li, Yanghua
2018-01-01
August Wilson's "Two Trains Running" tells the life predicaments of the patrons at Memphis' restaurant in the 1960s. Though Wilson avoids addressing the interracial conflicts and movements on stage to eschew protesting and propaganda, they as social background could not be totally ignored in the play. The paper analyses Wilson's use of…
Directory of Open Access Journals (Sweden)
Elham Azimzadeh
2013-01-01
Full Text Available Objectives: Falling is a main cause of mortality in elderly. Balance training exercises can help to prevent falls in older adults. According to the principle of specificity of training, the perturbation-based trainings are more similar to the real world. So these training programs can improve balance in elderly. Furthermore, exercising in an aquatic environment can reduce the limitations for balance training rather than a non-aquatic on. The aim of this study is comparing the effectiveness of perturbed and non-perturbed balance training programs in water on static and dynamic balance in aforementioned population group. Methods & Materials: 37 old women (age 80-65, were randomized to the following groups: perturbation-based training (n=12, non-perturbation-based training (n=12 and control (n=13 groups. Static and dynamic balance had been tested before and after the eight weeks of training by the postural stability test of the Biodex balance system using dynamic (level 4 and static platform. The data were analyzed by one sample paired t-test, Independent t-test and ANOVA. Results: There was a significant improvement for all indexes of static and dynamic balance in perturbation-based training (P<0.05. However, in non-perturbed group, all indexes were improved except ML (P<0.05. ANOVA showed that perturbed training was more effective than non-perturbed training on both static and dynamic balances. Conclusion: The findings confirmed the specificity principle of training. Although balance training can improve balance abilities, these kinds of trainings are not such specific for improving balance neuromuscular activities.The perturbation-based trainings can activate postural compensatory responses and reduce falling risk. According to results, we can conclude that hydrotherapy especially with perturbation-based programs will be useful for rehabilitation interventions in elderly .
Non-Perturbative QCD Coupling and Beta Function from Light Front Holography
International Nuclear Information System (INIS)
Brodsky, Stanley J.
2010-01-01
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 α 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 ∼ 1 GeV. The resulting β-function appears to capture the essential characteristics of the full β-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 α s AdS (Q 2 ).
Non-perturbative QCD Effects and the Top Mass at the Tevatron
Wicke, Daniel
2008-01-01
The modelling of non-perturbative effects is an important part of modern collider physics simulations. In hadron collisions there is some indication that the modelling of the interactions of the beam remnants, the underlying event, may require non-trivial colour reconnection effects to be present. We recently introduced a universally applicable toy model of such reconnections, based on hadronising strings. This model, which has one free parameter, has been implemented in the Pythia event generator. We then considered several parameter sets (`tunes'), constrained by fits to Tevatron minimum-bias data, and determined the sensitivity of a simplified top mass analysis to these effects, in exclusive semi-leptonic top events at the Tevatron. A first attempt at isolating the genuine non-perturbative effects gave an estimate of order +-0.5GeV from non-perturbative uncertainties. The results presented here are an update to the original study and include recent bug fixes of Pythia that influenced the tunings investigat...
Duality covariant type-IIB supersymmetry and nonperturbative consequences
International Nuclear Information System (INIS)
Bars, I.
1997-01-01
Type-IIB supersymmetric theories have an SL(2,Z) invariance, known as U duality, which controls the nonperturbative behavior of the theory. Under SL(2,Z) the supercharges are doublets, implying that the bosonic charges would be singlets or triplets. However, among the bosonic charges there are doublet strings and doublet five-branes which are in conflict with the doublet property of the supercharges. It is shown that the conflict is resolved by structure constants that depend on moduli, such as the tau parameter, which transform under the same SL(2,Z). The resulting superalgebra encodes the nonperturbative duality properties of the theory and is valid for any value of the string coupling constant. The usefulness of the formalism is illustrated by applying it to purely algebraic computations of the tension of (p,q) strings, and the mass and entropy of extremal black holes constructed from D-1-branes and D-5-branes. In the latter case the nonperturbative coupling dependence of the BPS mass and renormalization is computed for the first time in this paper. It is further argued that the moduli dependence of the superalgebra provides hints for four more dimensions beyond ten, such that the superalgebra is embedded in a fundamental theory which would be covariant under SO(11,3). An outline is given for a matrix theory in 14 dimensions that would be consistent with M(atrix) theory as well as with the above observations. copyright 1997 The American Physical Society
Improving the lattice axial vector current
International Nuclear Information System (INIS)
Horsley, R.; Perlt, H.; Schiller, A.; Zanotti, J.M.
2015-11-01
For Wilson and clover fermions traditional formulations of the axial vector current do not respect the continuum Ward identity which relates the divergence of that current to the pseudoscalar density. Here we propose to use a point-split or one-link axial vector current whose divergence exactly satisfies a lattice Ward identity, involving the pseudoscalar density and a number of irrelevant operators. We check in one-loop lattice perturbation theory with SLiNC fermion and gauge plaquette action that this is indeed the case including order O(a) effects. Including these operators the axial Ward identity remains renormalisation invariant. First preliminary results of a nonperturbative check of the Ward identity are also presented.
Operator product expansion on the lattice: analytic Wilson coefficients
Perlt, Holger
2006-12-01
We present first results for Wilson coefficients of operators up to first order in the covariant deriva- tives for the case of Wilson fermions. They are derived from the off-shell Compton scattering amplitude Wµν (a, p, q) of massless quarks with momentum p. The Wilson coefficients are clas- sified according to the transformation of the corresponding operators under the hypercubic group H(4). We give selected examples for a special choice of the momentum transfer q. All Wil- son coefficients are given in closed analytic form and in an expansion in powers of a up to first corrections.
A non-perturbative definition of 2D quantum gravity by the fifth time action
International Nuclear Information System (INIS)
Ambjoern, J.; Greensite, J.; Varsted, S.
1990-07-01
The general formalism for stabilizing bottomless Euclidean field theories (the 'fifth-time' action) provides a natural non-perturbative definition of matrix models corresponding to 2d quantum gravity. The formalism allows, in principle, the use of lattice Monte Carlo techniques for non-perturbative computation of correlation functions. (orig.)
Non-perturbative topological strings and conformal blocks
Cheng, M.C.N.; Dijkgraaf, R.; Vafa, C.
2011-01-01
We give a non-perturbative completion of a class of closed topological string theories in terms of building blocks of dual open strings. In the specific case where the open string is given by a matrix model these blocks correspond to a choice of integration contour. We then apply this definition to
Density-dependent mass gain by Wilson's Warblers during stopover
Jeffrey F. Kelly; Linda S. DeLay; Deborah M. Finch
2002-01-01
The need restore energetic reserves at stopover sites constrains avian migration ecology. To describe that constraint, we examined relationships among mass gained by Wilson's Warblers (Wilsonia pusilla) during stopover, abundance of Wilson's Warblers (i.e. capture rate), and arthropod abundance during autumn migration. We found that amount...
Large Wilson loop averages from the Schwinger-Dyson equation
International Nuclear Information System (INIS)
Xue Shesheng
1987-01-01
Using Schwinger-Dyson equations for the large Wilson loop in abelian lattice gauge theories, we evaluate the vacuum expectation values of the Wilson loop of sizes 1x2, 2x2, 2x3, and so on, from which the string tension is extracted. (orig.)
How Is Wilson Disease Inherited?
... News & Announcements Wilson's Warriors Events Back The Big WOW 2018 Annual Conference WDA Publications Back Downloads Corporate Sponsorship Forms Membership Forms Resources The Big WOW Newsletters News Copper Connection Newsletter Resources Centers of ...
How Is Wilson Disease Diagnosed?
... News & Announcements Wilson's Warriors Events Back The Big WOW 2018 Annual Conference WDA Publications Back Downloads Corporate Sponsorship Forms Membership Forms Resources The Big WOW Newsletters News Copper Connection Newsletter Resources Centers of ...
Non-perturbative effects in supersymmetry
International Nuclear Information System (INIS)
Veneziano, G.
1987-01-01
Some non perturbative aspects of globally supersymmetric (SUSY) gauge theories are discussed. These share with their non-supersymmetric analogues interesting non perturbative features, such as the spontaneous breaking of chiral symmetries via condensates. What is peculiar about supersymmetric theories, however, is that one is able to say a lot about non-perturbative effects even without resorting to elaborate numerical calculations: general arguments, supersymmetric and chiral Ward identities and analytic, dynamical calculations will turn out to effectively determine most of the supersymmetric vacuum properties. 28 references, 5 figures
On the nonperturbative foundations of the dipole picture
Energy Technology Data Exchange (ETDEWEB)
Ewerz, C. [Milano Univ., INFN, Dipt. di Fisica (Italy); ECT, Villazzano (Trento) (Italy); Nachtmannc, B.O. [Heidelberg Univ., Institut fur Theoretische Physik (Germany)
2005-07-01
Starting from a completely non-perturbative formulation of photon-proton scattering we have identified the assumptions and approximations that are needed in order to obtain the dipole picture at high energies. At the same time we have found corrections to the dipole picture which can become large at small photon virtualities. We consider it as an important task for the future to investigate in detail the validity of the assumptions, the accuracy of the approximations, and the size of the corrections. In our opinion these issues should be addressed in order to put the results obtained in the framework of the dipole picture on solid ground. The framework developed here should be suitable for studying the effects caused by the non-existence of a mass-shell for quarks, and for using non-perturbative quark propagators, obtained for example from Dyson-Schwinger equations or from lattice simulations.
Gauge-invariant, nonperturbative approach to the infrared-finite bound-state problem in QCD
International Nuclear Information System (INIS)
Gogokhia, V.Sh.
1989-09-01
Gauge invariant, nonperturbative approach to the bound state problem within the infrared finite Bethe-Salpeter equation is presented. Condition of cancellation of the nonperturbative infrared divergences is derived. Solutions for the quark propagator and corresponding quark gluon vertex function are written down which can be directly applied to the Bethe-Salpeter equation, in particular to the 'generalized ladder' approximation of this equation. (author) 18 refs.; 3 figs
Nonperturbative treatment of reduced model with fermions
International Nuclear Information System (INIS)
Gutierrez, W.R.
1983-01-01
A nonperturbative method is presented to show that the reduced model produces the correct leading large-N contribution to the fermion Green's functions. A new form of the reduced model is introduced, which avoids the quenching procedure. Also the equation for the meson bound states is discussed. The method is illustrated in the case of two-dimensional QCD
Non-Perturbative QCD Coupling and Beta Function from Light Front Holography
Energy Technology Data Exchange (ETDEWEB)
Brodsky, Stanley J.; /SLAC /Southern Denmark U., CP3-Origins; de Teramond, Guy F.; /Costa Rica U.; 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}).
Nonperturbative QCD with modern tools
International Nuclear Information System (INIS)
Roberts, C.D.
1998-01-01
In these lectures the author introduces and explores a range of topics of contemporary interest in hadronic physics: from what drives the formation of a nonzero quark condensate to the effect that mechanism has on light and heavy meson form factors and the properties of the quark-gluon plasma. The trail leads naturally through a discussion of confinement, dynamical chiral symmetry breaking and bound state structure: phenomena that require nonperturbative methods for their explanation. In all of this, the necessary and necessarily momentum-dependent modification of the quark and gluon propagators plays a significant role
Scaling properties of Wilson loops pierced by P-vortices
DEFF Research Database (Denmark)
Dunn, Patrick; Greensite, Jeffrey Paul
2012-01-01
P-vortices, in an SU(N) lattice gauge theory, are excitations on the center-projected Z(N) lattice. We study the ratio of expectation values of SU(2) Wilson loops, on the unprojected lattice, linked to a single P-vortex, to that of Wilson loops which are not linked to any P-vortices. When...
Parallel tempering in full QCD with Wilson fermions
International Nuclear Information System (INIS)
Ilgenfritz, E.-M.; Kerler, W.; Mueller-Preussker, M.; Stueben, H.
2002-01-01
We study the performance of QCD simulations with dynamical Wilson fermions by combining the hybrid Monte Carlo algorithm with parallel tempering on 10 4 and 12 4 lattices. In order to compare tempered with standard simulations, covariance matrices between subensembles have to be formulated and evaluated using the general properties of autocorrelations of the parallel tempering algorithm. We find that rendering the hopping parameter κ dynamical does not lead to an essential improvement. We point out possible reasons for this observation and discuss more suitable ways of applying parallel tempering to QCD
Wilson loop's phase transition probed by non-local observable
Directory of Open Access Journals (Sweden)
Hui-Ling Li
2018-04-01
Full Text Available In order to give further insights into the holographic Van der Waals phase transition, it would be of great interest to investigate the behavior of Wilson loop across the holographic phase transition for a higher dimensional hairy black hole. We offer a possibility to proceed with a numerical calculation in order to discussion on the hairy black hole's phase transition, and show that Wilson loop can serve as a probe to detect a phase structure of the black hole. Furthermore, for a first order phase transition, we calculate numerically the Maxwell's equal area construction; and for a second order phase transition, we also study the critical exponent in order to characterize the Wilson loop's phase transition.
Nonperturbative QED vacuum birefringence
Energy Technology Data Exchange (ETDEWEB)
Denisov, V.I.; Dolgaya, E.E.; Sokolov, V.A. [Physics Department, Moscow State University,Moscow, 119991 (Russian Federation)
2017-05-19
In this paper we represent nonperturbative calculation for one-loop Quantum Electrodynamics (QED) vacuum birefringence in presence of strong magnetic field. The dispersion relations for electromagnetic wave propagating in strong magnetic field point to retention of vacuum birefringence even in case when the field strength greatly exceeds Sauter-Schwinger limit. This gives a possibility to extend some predictions of perturbative QED such as electromagnetic waves delay in pulsars neighbourhood or wave polarization state changing (tested in PVLAS) to arbitrary magnetic field values. Such expansion is especially important in astrophysics because magnetic fields of some pulsars and magnetars greatly exceed quantum magnetic field limit, so the estimates of perturbative QED effects in this case require clarification.
Woodrow Wilson: Prophet of Peace. Teaching with Historic Places.
Goehner, Thomas B.
This lesson describes President Woodrow Wilson's struggle with and his ultimate failure at achieving lasting world peace through the League of Nations. The lesson focuses on November 23, 1923, the eve of the fifth anniversary of the Armistice that concluded World War I, when a frail and ill Wilson was ready to deliver a commemorative address by…
Nonperturbative infrared dynamics in three dimensional QED
International Nuclear Information System (INIS)
Gusynin, V.P.
2000-01-01
A non-linear Schwinger-Dyson (SD) equation for the gauge boson propagator of massless QED in 2 + 1 dimensions is studied. It is shown that the nonperturbative solution leads to a non-trivial renormalization-group infrared fixed point quantitatively close to the one found in the leading order of the 1/N expansion, with N the number of fermion flavors
Nonperturbative aspects of Yang-Mills theory
International Nuclear Information System (INIS)
Schleifenbaum, Wolfgang
2008-01-01
The subject of this thesis is the theory of strong interactions of quarks and gluons, with particular emphasis on nonperturbative aspects of the gluon sector. Continuum methods are used to investigate in particular the confinement phenomenon. Confinement which states that the elementary quarks and gluons cannot be detected as free particles requires an understanding of large-scale correlations. In perturbation theory, only short-range correlations can be reliably described. A nonperturbative approach is given by the set of integral Dyson Schwinger equations involving all Green functions of the theory. A solution for the gluon propagator is obtained in the infrared and ultraviolet asymptotic limits. In chapter 1, redundant degrees of freedom of the Yang Mills gauge theory are removed by fixing the Weyl and Coulomb gauge prior to quantization. The constrained quantization in the Dirac bracket formalism is then performed explicitly to produce the quantized Yang Mills Hamiltonian. The asymptotic infrared limits of Coulomb gauge correlation functions are studied analytically in chapter 2 in the framework of the Gribov Zwanziger confinement scenario. The Coulomb potential between heavy quarks as part of the Yang Mills Hamiltonian is calculated in this limit. A connection between the infrared limits of Coulomb and Landau gauge is established. The Hamiltonian derived paves the way in chapter 3 for finding the Coulomb gauge vacuum wave functional by means of the variational principle. Numerical solutions for the propagators in this vacuum state are discussed and seen to reproduce the anticipated infrared limit. The discussion is extended to the vertex functions. The effect of the approximations on the results is examined. Chapter 4 is mainly devoted to the ultraviolet behavior of the propagators. The discussion is issued in both Coulomb and Landau gauge. A nonperturbative running coupling is defined and calculated. The ultraviolet tails of the variational solutions from
Nonperturbative aspects of Yang-Mills theory
Energy Technology Data Exchange (ETDEWEB)
Schleifenbaum, Wolfgang
2008-07-01
The subject of this thesis is the theory of strong interactions of quarks and gluons, with particular emphasis on nonperturbative aspects of the gluon sector. Continuum methods are used to investigate in particular the confinement phenomenon. Confinement which states that the elementary quarks and gluons cannot be detected as free particles requires an understanding of large-scale correlations. In perturbation theory, only short-range correlations can be reliably described. A nonperturbative approach is given by the set of integral Dyson Schwinger equations involving all Green functions of the theory. A solution for the gluon propagator is obtained in the infrared and ultraviolet asymptotic limits. In chapter 1, redundant degrees of freedom of the Yang Mills gauge theory are removed by fixing the Weyl and Coulomb gauge prior to quantization. The constrained quantization in the Dirac bracket formalism is then performed explicitly to produce the quantized Yang Mills Hamiltonian. The asymptotic infrared limits of Coulomb gauge correlation functions are studied analytically in chapter 2 in the framework of the Gribov Zwanziger confinement scenario. The Coulomb potential between heavy quarks as part of the Yang Mills Hamiltonian is calculated in this limit. A connection between the infrared limits of Coulomb and Landau gauge is established. The Hamiltonian derived paves the way in chapter 3 for finding the Coulomb gauge vacuum wave functional by means of the variational principle. Numerical solutions for the propagators in this vacuum state are discussed and seen to reproduce the anticipated infrared limit. The discussion is extended to the vertex functions. The effect of the approximations on the results is examined. Chapter 4 is mainly devoted to the ultraviolet behavior of the propagators. The discussion is issued in both Coulomb and Landau gauge. A nonperturbative running coupling is defined and calculated. The ultraviolet tails of the variational solutions from
Nonperturbative quantum electrodynamics at T≠0
International Nuclear Information System (INIS)
Pevzner, M.Sh.
1990-01-01
On the base of Schwinger-Dyson equation for the electron temperature Green's function in the nonperturbative QED in the ladder approximation the ordinary differential equation for the function, connected with temperature one has been obtained. The relation, to which the temperature depending electron mass m(T) satisfies, has been found; its low-temperature behaviour has been studied. The phase transition has been shown to take place in the model, that is accompanied by the chiral symmetry restoration. 34 refs
Light hadron spectrum in 2+1 flavor full QCD by CP-PACS and JLQCD Collaborations
International Nuclear Information System (INIS)
Ishikawa, T.; Aoki, S.; Fukugita, M.; Hashimoto, S.; Ishikawa, K-I.; Ishizuka, N.; Iwasaki, Y.; Kanaya, K.; Kaneko, T.; Kuramashi, Y.; Okawa, M.; Onogi, T.; Taniguchi, N.; Tsutsui, N.; Ukawa, A.; Yoshie, T.
2005-01-01
CP-PACS and JLQCD Collaborations are carrying out a joint project of the 2+1 flavor full QCD with the RG-improved gauge action and the non-perturbatively O(a)-improved Wilson quark action. This simulation removes quenching effects of all three light quarks, which is the last major uncertainty in lattice QCD. In this report we present our results for the light meson spectrum and quark masses on a 20 3 x40 lattice at the lattice spacing a∼0.10 fm
The Wilson loop expectation values in 2-and 3-dimensional SU(2) LGT
International Nuclear Information System (INIS)
Li Zhibing; Zheng Weihong; Guo Shuohong
1989-01-01
An improved Monte Carlo scheme is applied to the computation of expectation values of nxm Wilson loops in both 2-and 3-dimensional SU(2) lattice gauge theories. The results are compared with those simulated by the discrete group Y 120 and the exact results in two dimensions
Spectral zeta function and non-perturbative effects in ABJM Fermi-gas
International Nuclear Information System (INIS)
Hatsuda, Yasuyuki
2015-03-01
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.
War, Medicine, and Cultural Diplomacy in the Americas: Frank Wilson and Brazilian cardiology.
Kropf, Simone P; Howell, Joel D
2017-10-01
American cultural diplomacy played a key role in the institutionalization of Brazilian cardiology. In 1942, Frank Wilson, an internationally recognized pioneer in electrocardiography, made an extended wartime visit to Rio de Janeiro and São Paulo. The visit was sponsored by the United States Department of State as part of Roosevelt's Good Neighbor Policy and brought Wilson together with a group of physicians who would establish the specialty of cardiology in Brazil. This US cultural and diplomatic initiative strengthened an academic network that was already evolving and would eventually prove to be of benefit to both sides. Latin American physicians began in the 1920s to visit Wilson's laboratory at the University of Michigan, where they established the relationships on which Wilson would build. While affiliation with the "Wilson school" advanced the cause of Brazilian cardiologists who sought to establish themselves as specialists, cooperation with Latin American physicians benefitted Wilson in his pursuit of wider recognition for his innovations in the use of electrocardiography (ECG). Wilson's identity as a scientific ambassador to Latin America helped in legitimating his approach to the clinical application of the ECG. A close examination of Wilson's relationship to Brazilian cardiology demonstrates the role played by science and medicine as a part of wartime cultural diplomacy, as well as the dynamics of the transnational circulation of scientific knowledge and practices. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
Determination of the static potential with dynamical fermions
Energy Technology Data Exchange (ETDEWEB)
Donnellan, Michael; Sommer, Rainer [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Knechtli, Francesco [Bergische Univ. Wuppertal (Germany). Dept. of Physics; Leder, Bjoern [Bergische Univ. Wuppertal (Germany). Dept. of Mathematics
2010-12-15
We present in detail a technique to extract the potential between a static quark and anti-quark pair from Wilson loops measured on dynamical configurations. This technique is based on HYP smearing and leads to an exponential improvement of the noise-to-signal ratio of Wilson loops. We explain why the correct continuum potential is obtained and show numerical evidence that the cut-off effects are small. We present precise results for the non-perturbative potential. As applications, we determine the scale r{sub 0}/a and study the shape of the static potential in the range of distances around r{sub 0}, where it can be compared with phenomenological potential models. (orig.)
Exact results for ABJ Wilson loops and open-closed duality
Energy Technology Data Exchange (ETDEWEB)
Hatsuda, Yasuyuki [Département de Physique Théorique et section de Mathématiques, Université de Genève,Genève, CH-1211 (Switzerland); Okuyama, Kazumi [Department of Physics, Shinshu University,Matsumoto 390-8621 (Japan)
2016-10-24
We find new exact relations between the partition function and vacuum expectation values (VEVs) of 1/2 BPS Wilson loops in ABJ theory, which allow us to predict the large N expansions of the 1/2 BPS Wilson loops from known results of the partition function. These relations are interpreted as an open-closed duality where the closed string background is shifted by the insertion of Wilson loops due to a back-reaction. Using the connection between ABJ theory and the topological string on local ℙ{sup 1}×ℙ{sup 1}, we explicitly write down non-trivial relations between open and closed string amplitudes.
Introduction to non-perturbative heavy quark effective theory
International Nuclear Information System (INIS)
Sommer, R.
2010-08-01
My lectures on the effective field theory for heavy quarks, an expansion around the static limit, concentrate on the motivation and formulation of HQET, its renormalization and discretization. This provides the basis for understanding that and how this effective theory can be formulated fully non-perturbatively in the QCD coupling, while by the very nature of an effective field theory, it is perturbative in the expansion parameter 1/m. After the couplings in the effective theory have been determined, the result at a certain order in 1/m is unique up to higher order terms in 1/m. In particular the continuum limit of the lattice regularized theory exists and leaves no trace of how it was regularized. In other words, the theory yields an asymptotic expansion of the QCD observables in 1/m - as usual in a quantum field theory modified by powers of logarithms. None of these properties has been shown rigorously (e.g. to all orders in perturbation theory) but perturbative computations and recently also non-perturbative lattice results give strong support to this ''standard wisdom''. A subtle issue is that a theoretically consistent formulation of the theory is only possible through a non-perturbative matching of its parameters with QCD at finite values of 1/m. As a consequence one finds immediately that the splitting of a result for a certain observable into, for example, lowest order and first order is ambiguous. Depending on how the matching between effective theory and QCD is done, a first order contribution may vanish and appear instead in the lowest order. For example, the often cited phenomenological HQET parameters anti Λ and λ 1 lack a unique non-perturbative definition. But this does not affect the precision of the asymptotic expansion in 1/m. The final result for an observable is correct up to order (1/m) n+1 if the theory was treated including (1/m) n terms. Clearly, the weakest point of HQET is that it intrinsically is an expansion. In practise, carrying it
Four-fluxes and non-perturbative superpotentials in two dimensions
International Nuclear Information System (INIS)
Lerche, W.
1998-01-01
We show how certain non-perturbative superpotentials W(Σ), which are the two-dimensional analogs of the Seiberg-Witten prepotential in 4d, can be computed via geometric engineering from 4-folds. We analyze an explicit example for which the relevant compact geometry of the 4-fold is given by P 1 fibered over P 2 . In the field theory limit, this gives an effective U(1) gauge theory with N=(2,2) supersymmetry in two dimensions. We find that the analog of the SW curve is a K3 surface, and that the complex FI coupling is given by the modular parameter of this surface. The FI potential itself coincides with the middle period of a meromorphic differential. However, it only shows up in the effective action if a certain 4-flux is switched on, and then supersymmetry appears to be non-perturbatively broken. (orig.)
Mowat–Wilson syndrome – case study
Directory of Open Access Journals (Sweden)
Kamil Faltin
2016-06-01
Full Text Available Mowat–Wilson syndrome is a rare genetic condition characterised by a number of congenital anomalies, including facial dysmorphia, heart and kidney anomalies, Hirschsprung’s disease, intellectual disability and abnormalities of reproductive organs. In the paper, we present a case of a girl who was admitted to the Department of Paediatrics, Immunology and Nephrology at the age of 3 months, with a suspicion of tubulointerstitial nephritis. The patient had facial dysmorphia, congenital malformations of the nervous system and Hirschsprung’s disease. During hospitalisation, congenital urinary anomalies (bilateral vesicoureteral reflux and heart defects were diagnosed. On the basis of the clinical picture, the diagnostics was expanded to genetic tests for Mowat–Wilson syndrome, which revealed an 857_858delAG pathogenic mutation in one of the ZEB2 gene alleles (exon 7 – one of the rarer causes of Mowat–Wilson syndrome. At present, the girl is 13 months old. Her development is delayed. Currently, the girl is under multidisciplinary care and she is undergoing intensive rehabilitation. The knowledge of the syndrome’s clinical features allows a faster diagnosis to be made and multispecialty care to be provided to the child.
Sextet Model with Wilson Fermions
DEFF Research Database (Denmark)
Hansen, Martin; Pica, Claudio
2017-01-01
We present new results from our ongoing study of the SU(3) sextet model with two flavors in the two-index symmetric representation of the gauge group. In the simulations use unimproved Wilson fermions to investigate the infrared properties of the model. We have previously presented results...
Coherent detection of THz-induced sideband emission from excitons in the nonperturbative regime
Uchida, K.; Otobe, T.; Mochizuki, T.; Kim, C.; Yoshita, M.; Tanaka, K.; Akiyama, H.; Pfeiffer, L. N.; West, K. W.; Hirori, H.
2018-04-01
Strong interaction of a terahertz (THz) wave with excitons induces nonperturbative optical effects such as Rabi splitting and high-order sideband generation. Here, we investigated coherent properties of THz-induced sideband emissions from GaAs/AlGaAs multiquantum wells. With increasing THz electric field, optical susceptibility of the THz-dressed exciton shows a redshift with spectral broadening and extraordinary phase shift. This implies that the field ionization of the 1 s exciton modifies the THz-dressed exciton in the nonperturbative regime.
The Wilson films--Huntington's chorea.
Klein, Christine
2011-12-01
Wilson's Queen Square Case 9 with Huntington's chorea shows a 68-year-old man with mild to moderate generalized chorea, impaired fixation, and probable cognitive decline in keeping with a diagnosis of Huntington's disease (HD). An age of onset in the late sixties and a negative family history suggest a relatively small expanded trinucleotide repeat in the HTT gene in the patient and reduced penetrance of an even shorter repeat allele in one of his parents. A highly sensitive and specific gene test has been offered worldwide for diagnostic testing of HD for almost two decades. This test, obviously unavailable at Wilson's times, became the historic frontrunner for guidelines of symptomatic, presymptomatic, and prenatal testing for an adult-onset neurodegenerative disorder. Regarding treatment of HD, however, we are still awaiting the successful translation of research results into the development of effective cause-directed, neuropreventive and neurorestaurative therapies. Copyright © 2011 Movement Disorder Society.
Zhang, Yu-Yu; Chen, Xiang-You
2017-01-01
A novel, unexplored nonperturbative deep-strong coupling (npDSC) achieved in superconducting circuits has been studied in the anisotropic Rabi model by the generalized squeezing rotating-wave approximation (GSRWA). Energy levels are evaluated analytically from the reformulated Hamiltonian and agree well with numerical ones under a wide range of coupling strength. Such improvement ascribes to deformation effects in the displaced-squeezed state presented by the squeezed momentum variance, which...
Directory of Open Access Journals (Sweden)
Nakamura Yoshifumi
2018-01-01
Full Text Available We investigate the critical end line of the finite temperature phase transition of QCD away from the SU(3-flavor symmetric point at zero chemical potential. We employ the renormalization-group improved Iwasaki gauge action and non-perturbatively O(a- improved Wilson-clover fermion action. The critical end line is determined by using the intersection point of kurtosis, employing the multi-parameter, multi-ensemble reweighting method at the temporal size NT = 6 and lattice spacing as low as a ≈0.19 fm.
Quantum geometry of resurgent perturbative/nonperturbative relations
Energy Technology Data Exchange (ETDEWEB)
Basar, Gökçe [Maryland Center for Fundamental Physics, University of Maryland, College Park, MD 20742 (United States); Dunne, Gerald V. [Department of Physics, University of Connecticut, Storrs, CT 06269-3046 (United States); Ünsal, Mithat [Department of Physics, North Carolina State University, Raleigh, NC 27695-8202 (United States)
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. 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. Our approach is very elementary, using basic classical geometry combined with all-orders WKB.
Determination of low-energy constants of Wilson chiral perturbation theory
International Nuclear Information System (INIS)
Herdoiza, Gregorio; Univ. Autonoma de Madrid, Contoblanco; Univ. Autonoma de Madrid; Jansen, Karl; Univ. Cyprus, Nicosia; Michael, Chris; Ottnad, Konstantin; Urbach, Carsten; Univ. Bonn
2013-03-01
By matching Wilson twisted mass lattice QCD determinations of pseudoscalar meson masses to Wilson Chiral Perturbation Theory we determine the low-energy constants W 6 ' , W 8 ' and their linear combination c 2 . We explore the dependence of these low-energy constants on the choice of the lattice action and on the number of dynamical flavours.
Insights on non-perturbative aspects of TMDs from models
Energy Technology Data Exchange (ETDEWEB)
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.
QCD and resonance physics Nonperturbative effects in operator expansion
International Nuclear Information System (INIS)
Shifman, M.A.; Vainshtein, A.L.; Zakharov, V.I.
1978-01-01
The aim of the paper is to show that QCD provides well-defined predictions for a single resonance. The crucial point is the inclusion of power corrections to asymptotic freedom which are due to nonperturbative effects of QCD. Apart from presenting a general outline in intuitive terms the operator expansion for the product of external currents is discussed. It is argued that the effect of nonperturbative terms is twofold: a) they induce vacuum expectation values such as (0.1Gsub(μv)sup(a)Gsub(μv)sup(a)10), Gsub(μv)sup(a) being the gluon field strength tensor and b) they break the operator expansion itself starting from some critical dimension. The latter effect is suppressed as a high power of Q -2 where Q is the momentum carried by a current. Both a) and b) are examplified in the instanton physics but the whole approach is of more general value
The cerebral lesions of Wilson's disease on computer tomography
International Nuclear Information System (INIS)
Rodiek, S.
1983-01-01
M. Wilson is often being mistaken as such for several years and kept for psychosis or another extrapyramidal disease. When the disease causes neuro-psychiatric symptoms a certain part of cases shows typical lesions in CT mainly affecting the Nucleus lentiformis and frontal cortex. From our own material two cases of M. Wilson are shown and compared with two other cases with identical patterns of lesions following toxic and hypoxic brain damage. (orig.) [de
Wilson loops in Kerr gravitation
International Nuclear Information System (INIS)
Bollini, C.G.; Giambiagi, J.J.; Tiomno, J.
1981-01-01
The ordered integrals for several paths in Kerr gravitation is computed in a compact form. When the path is closed its relation with the angular parallel displacement is discussed and the corresponding Wilson loop is calculated. The validity of Mandelstam relations for gauge fields is also explicitly verified. (Author) [pt
Robert Wilson's Invitation to Insanity.
Stephens, Judith L.
The plays of stage director Robert Wilson are devices presenting alternative modes of perception to theatre audiences accustomed to verbal/aural structures of experience. Uniting his interests in the arts and therapy, his plays create a theatrical event promoting empathy with the perceptions of the mentally or physically handicapped and…
International Nuclear Information System (INIS)
Khan, A.A.; Goeckeler, M.; Haegler, P.
2006-03-01
We present data for the axial coupling constant g A of the nucleon obtained in lattice QCD with two degenerate flavours of dynamical non-perturbatively improved Wilson quarks. The renormalisation is also performed non-perturbatively. For the analysis we give a chiral extrapolation formula for g A based on the small scale expansion scheme of chiral effective field theory for two degenerate quark flavours. Applying this formalism in a finite volume we derive a formula that allows us to extrapolate our data simultaneously to the infinite volume and to the chiral limit. Using the additional lattice data in finite volume we are able to determine the axial coupling of the nucleon in the chiral limit without imposing the known value at the physical point. (Orig.)
Energy Technology Data Exchange (ETDEWEB)
Khan, A.A.; Goeckeler, M. [Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Haegler, P. [Technische Univ. Muenchen (DE). Physik-Department, Theoretische Physik] (and others)
2006-03-15
We present data for the axial coupling constant g{sub A} of the nucleon obtained in lattice QCD with two degenerate flavours of dynamical non-perturbatively improved Wilson quarks. The renormalisation is also performed non-perturbatively. For the analysis we give a chiral extrapolation formula for g{sub A} based on the small scale expansion scheme of chiral effective field theory for two degenerate quark flavours. Applying this formalism in a finite volume we derive a formula that allows us to extrapolate our data simultaneously to the infinite volume and to the chiral limit. Using the additional lattice data in finite volume we are able to determine the axial coupling of the nucleon in the chiral limit without imposing the known value at the physical point. (Orig.)
Neuroimaging findings in Mowat-Wilson syndrome
DEFF Research Database (Denmark)
Garavelli, Livia; Ivanovski, Ivan; Caraffi, Stefano Giuseppe
2017-01-01
PURPOSE: Mowat-Wilson syndrome (MWS) is a genetic disease characterized by distinctive facial features, moderate to severe intellectual disability, and congenital malformations, including Hirschsprung disease, genital and eye anomalies, and congenital heart defects, caused by haploinsufficiency o...
Parameters of heavy quark effective theory from N{sub f}=2 lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Blossier, Benoit [CNRS, Orsay (France). LPT; Paris-11 Univ., 91 - Orsay (France); Della Morte, Michele [Mainz Univ. (Germany). Inst. fuer Kernphysik; Fritzsch, Patrick [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Garron, Nicolas [Edinburgh Univ. (United Kingdom). School of Physics and Astronomy; Heitger, Jochen [Muenster Univ. (Germany). Inst. fuer Theoretische Physik 1; Simma, Hubert; Sommer, Rainer [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Tantalo, Nazario [Rome-3 Univ. (Italy). Dipt. di Fisica; INFN, Sezione di Roma (Italy)
2012-07-15
We report on a non-perturbative determination of the parameters of the lattice Heavy Quark Effective Theory (HQET) Lagrangian and of the time component of the heavy-light axial-vector current with N{sub f} = 2 flavors of massless dynamical quarks. The effective theory is considered at the 1/m{sub h} order, and the heavy mass m{sub h} covers a range from slightly above the charm to beyond the beauty region. These HQET parameters are needed to compute, for example, the b-quark mass, the heavy-light spectrum and decay constants in the static approximation and to order 1/m{sub h} in HQET. The determination of the parameters is done non-perturbatively. The computation reported in this paper uses the plaquette gauge action and two different static actions for the heavy quark described by HQET. For the light-quark action we choose non-perturbatively O(a)-improved Wilson fermions.
Nonperturbative approach to the attractive Hubbard model
International Nuclear Information System (INIS)
Allen, S.; Tremblay, A.-M. S.
2001-01-01
A nonperturbative approach to the single-band attractive Hubbard model is presented in the general context of functional-derivative approaches to many-body theories. As in previous work on the repulsive model, the first step is based on a local-field-type ansatz, on enforcement of the Pauli principle and a number of crucial sumrules. The Mermin-Wagner theorem in two dimensions is automatically satisfied. At this level, two-particle self-consistency has been achieved. In the second step of the approximation, an improved expression for the self-energy is obtained by using the results of the first step in an exact expression for the self-energy, where the high- and low-frequency behaviors appear separately. The result is a cooperon-like formula. The required vertex corrections are included in this self-energy expression, as required by the absence of a Migdal theorem for this problem. Other approaches to the attractive Hubbard model are critically compared. Physical consequences of the present approach and agreement with Monte Carlo simulations are demonstrated in the accompanying paper (following this one)
Non-perturbative treatment of relativistic quantum corrections in large Z atoms
International Nuclear Information System (INIS)
Dietz, K.; Weymans, G.
1983-09-01
Renormalised g-Hartree-Dirac equations incorporating Dirac sea contributions are derived. Their implications for the non-perturbative, selfconsistent calculation of quantum corrections in large Z atoms are discussed. (orig.)
Indian Academy of Sciences (India)
The best reference for anyone interested in the development of Wilson's thinking in this period ... work on the critical point was a seminar in the Chemistry Department by his ... The basic theoretical tool used was the renormalization group.
Introduction to non-perturbative heavy quark effective theory
Energy Technology Data Exchange (ETDEWEB)
Sommer, R. [DESY, Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC
2010-08-15
My lectures on the effective field theory for heavy quarks, an expansion around the static limit, concentrate on the motivation and formulation of HQET, its renormalization and discretization. This provides the basis for understanding that and how this effective theory can be formulated fully non-perturbatively in the QCD coupling, while by the very nature of an effective field theory, it is perturbative in the expansion parameter 1/m. After the couplings in the effective theory have been determined, the result at a certain order in 1/m is unique up to higher order terms in 1/m. In particular the continuum limit of the lattice regularized theory exists and leaves no trace of how it was regularized. In other words, the theory yields an asymptotic expansion of the QCD observables in 1/m - as usual in a quantum field theory modified by powers of logarithms. None of these properties has been shown rigorously (e.g. to all orders in perturbation theory) but perturbative computations and recently also non-perturbative lattice results give strong support to this ''standard wisdom''. A subtle issue is that a theoretically consistent formulation of the theory is only possible through a non-perturbative matching of its parameters with QCD at finite values of 1/m. As a consequence one finds immediately that the splitting of a result for a certain observable into, for example, lowest order and first order is ambiguous. Depending on how the matching between effective theory and QCD is done, a first order contribution may vanish and appear instead in the lowest order. For example, the often cited phenomenological HQET parameters anti {lambda} and {lambda}{sub 1} lack a unique non-perturbative definition. But this does not affect the precision of the asymptotic expansion in 1/m. The final result for an observable is correct up to order (1/m){sup n+1} if the theory was treated including (1/m){sup n} terms. Clearly, the weakest point of HQET is that it
Determination of low-energy constants of Wilson chiral perturbation theory
Energy Technology Data Exchange (ETDEWEB)
Herdoiza, Gregorio [Mainz Univ. (Germany). Inst fuer Kernphysik, PRISMA Cluster of Excellence; Univ. Autonoma de Madrid, Contoblanco (Spain). Dept. de Fisica Teorica; Univ. Autonoma de Madrid (Spain). Inst. de Fisica Teorica UAM/CSIC; Jansen, Karl [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Univ. Cyprus, Nicosia (Cyprus). Dept. of Physics; Michael, Chris [Liverpool Univ. (United Kingdom). Theoretical Physics Division; Ottnad, Konstantin; Urbach, Carsten [Bonn Univ. (Germany). Helmholtz-Institut fuer Strahlen und Kernphysik; Univ. Bonn (Germany). Bethe Center for Theoretical Physics; Collaboration: European Twisted Mass Collaboration
2013-03-15
By matching Wilson twisted mass lattice QCD determinations of pseudoscalar meson masses to Wilson Chiral Perturbation Theory we determine the low-energy constants W{sub 6}{sup '}, W{sub 8}{sup '} and their linear combination c{sub 2}. We explore the dependence of these low-energy constants on the choice of the lattice action and on the number of dynamical flavours.
Wilson's disease in children: clinical and diagnostic features
International Nuclear Information System (INIS)
Ayesha, H.; Choudhry, A.A.; Javed, M.T.; Javed, F.
2002-01-01
copper excretion and free serum copper was noted in 79 % and 86 % of non neurologic type respectively. Liver biopsy revealed various grades of liver damage. Focal copper stores on rubeanic acid staining were seen in 2 out of 7 patients subjected to liver biopsy. Six (22%) patients died with in six months, 7(26%) were lost to follow-up and 14(52%) are being followed-up. Conclusion: Wilson's disease presents at an early age but at a late stage in our region Diagnosis can be made if it is suspected. Early diagnosis is essential for improving survival. Inter family marriages should be avoided to prevent disease. (author)
Non-supersymmetric Wilson loop in N = 4 SYM and defect 1d CFT
Beccaria, Matteo; Giombi, Simone; Tseytlin, Arkady A.
2018-03-01
Following Polchinski and Sully (arXiv:1104.5077), we consider a generalized Wilson loop operator containing a constant parameter ζ in front of the scalar coupling term, so that ζ = 0 corresponds to the standard Wilson loop, while ζ = 1 to the locally supersymmetric one. We compute the expectation value of this operator for circular loop as a function of ζ to second order in the planar weak coupling expansion in N = 4 SYM theory. We then explain the relation of the expansion near the two conformal points ζ = 0 and ζ = 1 to the correlators of scalar operators inserted on the loop. We also discuss the AdS5 × S 5 string 1-loop correction to the strong-coupling expansion of the standard circular Wilson loop, as well as its generalization to the case of mixed boundary conditions on the five-sphere coordinates, corresponding to general ζ. From the point of view of the defect CFT1 defined on the Wilson line, the ζ-dependent term can be seen as a perturbation driving a RG flow from the standard Wilson loop in the UV to the supersymmetric Wilson loop in the IR. Both at weak and strong coupling we find that the logarithm of the expectation value of the standard Wilson loop for the circular contour is larger than that of the supersymmetric one, which appears to be in agreement with the 1d analog of the F-theorem.
Large N non-perturbative effects in N=4 superconformal Chern-Simons theories
International Nuclear Information System (INIS)
Hatsuda, Yasuyuki; Honda, Masazumi; Okuyama, Kazumi
2015-07-01
We investigate the large N instanton effects of partition functions in a class of N = 4 circular quiver Chern-Simons theories on a three-sphere. Our analysis is based on the supersymmetry localization and the Fermi-gas formalism. The resulting matrix model can be regarded as a two-parameter deformation of the ABJM matrix model, and has richer non-perturbative structures. Based on a systematic semi-classical analysis, we find analytic expressions of membrane instanton corrections. We also exactly compute the partition function for various cases and find some exact forms of worldsheet instanton corrections, which appear as quantum mechanical non-perturbative corrections in the Fermi-gas system.
Nonperturbative Dynamics of Strong Interactions from Gauge/Gravity Duality
Energy Technology Data Exchange (ETDEWEB)
Grigoryan, Hovhannes [Louisiana State Univ., Baton Rouge, LA (United States)
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.
Consistent method of truncating the electron self-energy in nonperturbative QED
International Nuclear Information System (INIS)
Rembiesa, P.
1986-01-01
A nonperturbative method of solving the Dyson-Schwinger equations for the fermion propagator is considered. The solution satisfies the Ward-Takahashi identity, allows multiplicative regularization, and exhibits a physical-mass pole
A nonperturbative test of M2-brane theory
International Nuclear Information System (INIS)
Hosomichi, Kazuo; Lee, Ki-Myeong; Lee, Sungjay; Yi, Piljin; Lee, Sangmin; Park, Jaemo
2008-01-01
We discuss non-perturbative effects in the ABJM model due to monopole instantons. We begin by constructing the instanton solutions in the U(2) x U(2) model, explicitly, and computing the Euclidean action. The Wick-rotated Lagrangian is complex and its BPS monopole instantons are found to be a delicate version of the usual 't Hooft-Polyakov monopole solutions. They are generically 1/3 BPS but become 1/2 BPS at special locus in the moduli space of two M2-branes, yet each instanton carries eight fermionic zero modes, regardless of the vacuum choice. The low energy effective action induced by monopole instantons are quartic order in derivatives. The resulting vertices are nonperturbative in 1/k, as expected, but are rational functions of the vacuum moduli. We also analyze the system of two M2-branes in the supergravity framework and compute the higher order interactions via 11-dimensional supergraviton exchange. The comparison of the two shows that the instanton vertices are precisely reproduced by this M2-brane picture, supporting the proposal that the ABJM model describes multiple M2-branes.
Skein relations and Wilson loops in Chern-Simons gauge theory
International Nuclear Information System (INIS)
Horne, J.H.
1990-01-01
We derive the skein relations for the fundamental representations of SO(N), Sp(2n), SU(mvertical stroken), and OSp(mvertical stroke2n). These relations can be used recursively to calculate the expectation values of Wilson lines in three-dimensional Chern-Simons gauge theory with these gauge groups. A combination of braiding and tying of Wilson lines completely describes the skein relations. (orig.)
Renormalized sum rules for structure functions of heavy meson decays
International Nuclear Information System (INIS)
Grozin, A.G.; Korchemsky, G.P.
1996-01-01
We consider the properties of the structure functions of inclusive heavy meson decays B→X c and treat the c quark mass as a free parameter. We show that in two extreme cases of heavy and light c quarks the structure functions of heavy-heavy and heavy-light transitions are given by a Fourier transform of the matrix elements of Wilson lines containing a timelike and a lightlike segment, correspondingly. Using the renormalization properties of Wilson lines we find the dependence of the structure functions on the factorization scale, the structure function of the heavy-heavy transition is renormalized multiplicatively, while that of the heavy-light transition obeys the GLAP-type evolution equation. We propose a generalization of the sum rules for the moments of the structure functions (Bjorken, Voloshin, and the open-quote open-quote third close-quote close-quote sum rules) with a soft exponential factorization cutoff, which correctly incorporates both perturbative and nonperturbative effects. We analyze nonperturbative corrections by first considering infrared renormalon contributions to the Wilson lines. Uncertainties induced by the leading renormalon pole at u=1/2 are exactly canceled by a similar uncertainty in the heavy quark pole mass. The leading nonperturbative corrections associated with the next renormalon at u=1 are parametrized by the matrix element μ π 2 which is proportional to the heavy quark kinetic energy. copyright 1996 The American Physical Society
Non-perturbative particle dynamics in (2+1)-gravity
Bellini, A; Valtancoli, P
1995-01-01
We construct a non-perturbative, single-valued solution for the metric and the motion of two interacting particles in (2+1)-Gravity, by using a Coulomb gauge of conformal type. The method provides the mapping from multivalued ( minkowskian ) coordinates to single-valued ones, which solves the non-abelian monodromies due to particles's momenta and can be applied also to the general N-body case.
A profusion of 1/2 BPS Wilson loops in N=4 Chern-Simons-matter theories
International Nuclear Information System (INIS)
Cooke, Michael; Drukker, Nadav; Trancanelli, Diego
2015-01-01
We initiate the study of 1/2 BPS Wilson loops in N=4 Chern-Simons-matter theories in three dimensions. We consider a circular or linear quiver with Chern-Simons levels k, −k and 0, and focus on loops preserving one of the two SU(2) subgroups of the R-symmetry. In the cases with no vanishing Chern-Simons levels, we find a pair of Wilson loops for each pair of adjacent nodes on the quiver connected by a hypermultiplet (nodes connected by twisted hypermultiplets have Wilson loops preserving another set of supercharges). We expect this classical pairwise degeneracy to be lifted by quantum corrections. In the case with nodes with vanishing Chern-Simons terms connected by twisted hypermultiplets, we find that the usual 1/4 BPS Wilson loops are automatically enlarged to 1/2 BPS, as happens also in 3-dimensional Yang-Mills theory. When the nodes with vanishing Chern-Simons levels are connected by untwisted hypermultiplets, we do not find any Wilson loops coupling to those nodes which are classically invariant. Rather, we find several loops whose supersymmetry variation, while non zero, vanishes in any correlation function, so is weakly zero. We expect only one linear combination of those Wilson loops to remain BPS when quantum corrections are included. We analyze the M-theory duals of those Wilson loops and comment on their degeneracy. We also show that these Wilson loops are cohomologically equivalent to certain 1/4 BPS Wilson loops whose expectation value can be evaluated by the appropriate localized matrix model.
Holography of Wilson-loop expectation values with local operator insertions
International Nuclear Information System (INIS)
Miwa, Akitsugu; Yoneya, Tamiaki
2006-01-01
We study the expectation values of Wilson-loop operators with the insertions of local operators Z J and Z-bar J for large J from the bulk viewpoint of AdS/CFT correspondence. Classical solutions of strings attached to such deformed Wilson loops at the conformal boundary are constructed and are applied to the computation of Wilson-loop expectation values. We argue that in order to have such solutions for general insertions at finite positions in the base spacetime of the gauge theory, it is crucial to interpret the holographic correspondence in the semi-classical picture as a tunneling phenomenon, as has been previously established for holographic computations of correlators of BMN operators. This also requires to use the Euclideanized AdS background and Euclidean super Yang-Mills theory
Wilson Martins: between the intelligentsia and the university (1951
Directory of Open Access Journals (Sweden)
Névio de Campos
2012-05-01
Full Text Available Abstract The purpose of this article is to analyze the presence of Ortega y Gasset in the Parana’s State group during the 1950s, especially his influence in the thinking of Wilson Martins, and to emphasize the debate on the ideas of the intellectual and the university. The article discusses about the contributions of this Parana’s thinker on the Parana’s university teaching constituting and organizing process, and emphasizes that the Wilson Martins’ role consisted in promoting the debate on the presence of the intellectual person in modern society, attributing the mission as guardian of the moral and herald of cultural renovation, without forgetting the Brazilian and European political-cultural context as the founding background to higher education. It bases itself on the speech entitled “The rebellion against intelligence and the mission of the university”, that occurred at the University of Parana in 1951, and on the work The History of Brazilian Intelligence, written by Wilson Martins.
Testing QCD in the non-perturbative regime
Energy Technology Data Exchange (ETDEWEB)
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.
Non-perturbative BRST quantization of Euclidean Yang-Mills theories in Curci-Ferrari gauges
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.
Non-perturbative BRST quantization of Euclidean Yang-Mills theories in Curci-Ferrari gauges
International Nuclear Information System (INIS)
Pereira, A.D.; Sobreiro, R.F.; Sorella, S.P.
2016-01-01
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 [hepth], 2015). Finally, we pay attention to the gluon propagator in different space-time dimensions. (orig.)
Non-perturbative BRST quantization of Euclidean Yang-Mills theories in Curci-Ferrari gauges
Energy Technology Data Exchange (ETDEWEB)
Pereira, A.D. [UFF, Universidade Federal Fluminense, Instituto de Fisica, Campus da Praia Vermelha, Niteroi, RJ (Brazil); Max Planck Institute for Gravitational Physics, Albert Einstein Institute, Potsdam (Germany); UERJ, Universidade do Estado do Rio de Janeiro, Departamento de Fisica Teorica, Rio de Janeiro (Brazil); Sobreiro, R.F. [UFF, Universidade Federal Fluminense, Instituto de Fisica, Campus da Praia Vermelha, Niteroi, RJ (Brazil); Sorella, S.P. [UERJ, Universidade do Estado do Rio de Janeiro, Departamento de Fisica Teorica, Rio de Janeiro (Brazil)
2016-10-15
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 [hepth], 2015). Finally, we pay attention to the gluon propagator in different space-time dimensions. (orig.)
A nonperturbative study of quarkonium systems
International Nuclear Information System (INIS)
Ma, J.P.; McKellar, H.J.
1995-01-01
Using nonrelativistic QCD on the lattice we studied the mass spectrum of quarkonium systems nonperturbatively for a range of the bar quark mass. We determined two products of the matrix elements involved in quarkonium decays and studied the mass dependence of the results. We predict from our calculations the leptonic decay width of Υ, and use the mass dependence to predict the leptonic decay width of J/ψ. These calculations agree with the experimental results. In lattice NRQCD an additional parameter n is introduced, and we study the sensitivity of our results to the choice of n. (authors). 10 refs., 2 figs
Anesthesia in Mowat-Wilson syndrome: information on 11 Italian patients
Marianna Spunton; Livia Garavelli; Paola Cerutti Mainardi; Uta Emmig; Enrico Finale; Andrea Guala
2018-01-01
Mowat-Wilson syndrome is a genetic disease caused by heterozygous mutations or deletions of the ZEB2 gene and characterized by typical clinical features. The congenital malformations typical of this syndrome call for early diagnostic and surgical procedures requiring general anesthesia, but few information about the anesthesiology management of such patients is available. We enrolled 11 families of patients with Mowat-Wilson syndrome who had undergone surgical or diagnostic procedures requiri...
Face of the giant panda sign in Wilson disease
Directory of Open Access Journals (Sweden)
Sumit Chakraborty
2013-08-01
Full Text Available Wilson disease usually presents with neurologic or hepatic manifestations. Magnetic resonance imaging (MRI of the brain is very informative in diagnosiing of this disease, especially in patients with neurological features. High T2 signal intensity in the corpus striatum is the most commonly encountered MRI finding. The 'face of the giant panda' sign is seen on axial T2-weighted MRI, and results from abnormal signal intensities in the midbrain. Though uncommon, the sign is considered as the pathognomonic MRI sign of Wilson disease.
Renormalization constants for 2-twist operators in twisted mass QCD
International Nuclear Information System (INIS)
Alexandrou, C.; Constantinou, M.; Panagopoulos, H.; Stylianou, F.; Korzec, T.
2011-01-01
Perturbative and nonperturbative results on the renormalization constants of the fermion field and the twist-2 fermion bilinears are presented with emphasis on the nonperturbative evaluation of the one-derivative twist-2 vector and axial-vector operators. Nonperturbative results are obtained using the twisted mass Wilson fermion formulation employing two degenerate dynamical quarks and the tree-level Symanzik improved gluon action. The simulations have been performed for pion masses in the range of about 450-260 MeV and at three values of the lattice spacing a corresponding to β=3.9, 4.05, 4.20. Subtraction of O(a 2 ) terms is carried out by performing the perturbative evaluation of these operators at 1-loop and up to O(a 2 ). The renormalization conditions are defined in the RI ' -MOM scheme, for both perturbative and nonperturbative results. The renormalization factors, obtained for different values of the renormalization scale, are evolved perturbatively to a reference scale set by the inverse of the lattice spacing. In addition, they are translated to MS at 2 GeV using 3-loop perturbative results for the conversion factors.
MR of the liver in Wilson's disease
International Nuclear Information System (INIS)
Vogl, T.J.; Steiner, S.; Hammerstingl, R.; Schwarz, S.; Kraft, E.; Weinzierl, M.; Felix, R.
1994-01-01
To show that Wilson's disease is one likely cause of multiple low-intensity nodules of the liver we obtained MR images in 16 patients with clinically and histopathologically confirmed Wilson's disease. Corresponding to morphological changes MRI enabled the subdivision of the patients into two groups. Using a T 2 -weighted spin-echo sequence (TR/TE=2000/45-90) liver parenchyma showed multiple tiny low-intensity-nodules surrounded by high-intensity septa in 10 out of 16 patients. 5 patients had also low-intensity nodules in T 1 -weighted images (TR/TE=600/20). In patients of this group histopathology revealed liver cirrhosis (n=7) and fibrosis (n=2). Common feature of this patient group was marked inflammatory cell infiltration into fibrous septa, increase of copper concentration in liver parenchyma and distinct pathological changes of laboratory data. In the remaining 6 patients no pathological change of liver morphology was demonstrated by MRI corresponding to slight histopathological changes of parenchyma and normal laboratory data. As low-intensity nodules surrounded by high intensity septa can be demonstrated in patients with marked inflammatory infiltration of liver parenchyma MRI may help to define Wilson patients with poorer prognosis. In patients with low-intensity nodules of the liver and unknown cause of liver cirrhosis laboratory data and histopathology should be checked when searching for disorders of copper metabolism. (orig.) [de
Theoretical nuclear physics---elementary particles
International Nuclear Information System (INIS)
Kuti, J.
1989-01-01
This report briefly discusses the following topics: Thermodynamics with Wilson Fermions; beta function with Wilson Fermions; grand challenge; light flavors and nonperturbative QCD; the spin structure of the proton; the heavy Higgs Meson Problem; the heavy top quark problem; SU(2) Higgs Model; nontrivial quantum electrodynamics; vortex sheet dynamics; random surfaces and quantum gravity; strange baryon matter; supersymmetric model with the Higgs as a lepton; and Hamilton equations on group manifolds
Wilson fermions at finite temperature
International Nuclear Information System (INIS)
Creutz, M.
1996-01-01
The author conjectures on the phase structure expected for lattice gauge theory with two flavors of Wilson fermions, concentrating on large values of the hopping parameter. Numerous phases are expected, including the conventional confinement and deconfinement phases, as well as an Aoki phase with spontaneous breaking of flavor and parity and a large hopping phase corresponding to negative quark masses
Non-perturbative Green functions in quantum gauge theories
International Nuclear Information System (INIS)
Shabanov, S.V.
1991-01-01
Non-perturbative Green functions for gauge invariant variables are considered. The Green functions are found to be modified as compared with the usual ones in a definite gauge because of a physical configuration space (PCS) reduction. In the Yang-Mills theory with fermions this phenomenon follows from the Singer theorem about the absence of a global gauge condition for the fields tensing to zero at spatial infinity. 20 refs
Wilson Fermions with Four Fermion Interactions
DEFF Research Database (Denmark)
Rantaharju, Jarno; Drach, Vincent; Hietanen, Ari
2015-01-01
We present a lattice study of a four fermion theory, known as Nambu Jona-Lasinio (NJL) theory, via Wilson fermions. Four fermion interactions naturally occur in several extensions of the Standard Model as a low energy parameterisation of a more fundamental theory. In models of dynamical electroweak...
International Nuclear Information System (INIS)
Rey, Soo-Jong; Suyama, Takao; Yamaguchi, Satoshi
2009-01-01
We study Wilson loop operators in three-dimensional, N = 6 superconformal Chern-Simons theory dual to IIA superstring theory on AdS 4 x CP 3 . Novelty of Wilson loop operators in this theory is that, for a given contour, there are two linear combinations of Wilson loop transforming oppositely under time-reversal transformation. We show that one combination is holographically dual to IIA fundamental string, while orthogonal combination is set to zero. We gather supporting evidences from detailed comparative study of generalized time-reversal transformations in both D2-brane worldvolume and ABJM theories. We then classify supersymmetric Wilson loops and find at most 1/6 supersymmetry. We next study Wilson loop expectation value in planar perturbation theory. For circular Wilson loop, we find features remarkably parallel to circular Wilson loop in N = 4 super Yang-Mills theory in four dimensions. First, all odd loop diagrams vanish identically and even loops contribute nontrivial contributions. Second, quantum corrected gauge and scalar propagators take the same form as those of N = 4 super Yang-Mills theory. Combining these results, we propose that expectation value of circular Wilson loop is given by Wilson loop expectation value in pure Chern-Simons theory times zero-dimensional Gaussian matrix model whose variance is specified by an interpolating function of 't Hooft coupling. We suggest the function interpolates smoothly between weak and strong coupling regime, offering new test ground of the AdS/CFT correspondence.
Nonperturbative sum over topologies in 2-D Lorentzian quantum gravity
Loll, R.; Westra, W.; Zohren, S.
The recent progress in the Causal Dynamical Triangulations (CDT) approach to quantum gravity indicates that gravitation is nonperturbatively renormalizable. We review some of the latest results in 1+1 and 3+1 dimensions with special emphasis on the 1+1 model. In particular we discuss a
On the duality-transformed Wilson loop operator
International Nuclear Information System (INIS)
Mizrachi, L.
1981-08-01
Duality transformation of the vacuum expectation value of the Wilson loop operator is performed in the radial gauge (xsub(μ)Asub(μ)sup(a)(x) = 0). It is found to be equal, up to a multiplicative constant, to , where O(c) is a line integral along the loop c (defining the Wilson loop operator) of a function of the dual field variables. In the weak coupling region self duality is recovered in the sense that the Lagrangian is local gauge invariant defined in terms of the dual gauge potentials but with g (the coupling constant) replaced by 1/g, and O(c) is simply the line integral of the dual gauge potentials. For large g, a strong coupling expansion is suggested (but the theory is not local gauge invariant). (author)
Wilson disease : from clinical to molecular
Houwen, Roderick Henk Johan
1991-01-01
Wilson disease is an autosomal recessive copper storage disease. It is characterized by an inability of the liver to; excrete copper into bile and to incorporate copper into ceruloplasmin. This results in a gradual accumulation of copper in the liver and subsequently in the brain and other organs,
Indian Academy of Sciences (India)
perceptions of strongly interacting systems – either in particle physics or in condensed matter. The Nobel citation mentions the cryptic term 'renormalization group'. An article elsewhere in this issue ... young research student who had graduated from Harvard University in 1956 – Kenneth Wilson. Gell-Mann suggested that ...
Directory of Open Access Journals (Sweden)
Editorial, Equipo
1959-11-01
Full Text Available En la presa Wilson, construida sobre el río Tennessee, ya existía una esclusa y canal que permitía la navegación fluvial por el río. Este rio tiene un curso de difícil navegación en una extensión próxima a la presa, pero la construcción de canales y esclusas ha permitido mejorar estas vías navegables. Estos últimos años ha aumentado tanto la navegación, que la esclusa existente no bastaba para hacer frente al paso de tantas embarcaciones dedicadas al transporte de mercancías que, aún en competencia con él transporte por ferrocarril y carretera, ha llegado a un volumen anual de unos trece millones de toneladas.
Edwin B. Wilson and the rise of mathematical economics in America, 1920-1940
Carvajalino, Juan
2017-01-01
In the paper, Edwin B. Wilson's influence on the rise of mathematical economics in America between the 1920s and 1940s is explored. The focus is laid on showing how on the grounds of his foundational ideas about science Wilson worked at the organizational and educational fronts to modernize economics, at this at three levels. First, the paper shows the ways in which around 1930 Wilson was key, at the nationwide level, in the constitution of the first organized community of American mathematic...
Wilson's disease: an analysis of 28 Brazilian children
Directory of Open Access Journals (Sweden)
Rodolpho Truffa Kleine
2012-01-01
Full Text Available OBJECTIVES: Clinical-laboratory and evolutionary analysis of twenty-eight patients with Wilson's disease. METHODS: Twenty-eight children (twelve females and sixteen males with Wilson's disease were evaluated retrospectively between 1987 and 2009, with a follow-up of 72 months (1 - 240 months. The clinical, laboratory, and histologic features at diagnosis were recorded at the end of the study. RESULTS: The median age at diagnosis was 11 years (2 - 18 years. Twelve patients were asymptomatic, seven had hepatitis symptoms, five had raised aminotransferase levels, three had hepatomegaly associated with neurological disorders, one had fulminant hepatitis with hemolytic anemia, and six patients presented with a Kayser-Fleischer ring. A histological analysis revealed that six children had chronic hepatitis, seven had cirrhosis, two had steatosis, one had portal fibrosis, and one had massive necrosis. The treatment consisted of D-penicillamine associated with pyridoxine for 26 patients. Adverse effects were observed in the other two patients: one presented with uncontrollable vomiting and the other demonstrated elastosis perforans serpiginosa. At the end of the study, all 26 treated patients were asymptomatic. Twenty-four of the patients were treated with D-penicillamine and pyridoxine, and two were treated with trientine and zinc sulfate. A liver transplant was performed in one patient with fulminant hepatitis, but the final patient died 48 hours after admission to the intensive care unit. CONCLUSIONS: Family screenings associated with early treatment are important in preventing Wilson's disease symptoms and potentially fatal disease progression. The study suggests that Wilson's disease must be ruled out in children older than two years presenting with abnormal levels of hepatic enzymes because of the heterogeneity of symptoms and the encouraging treatment results obtained so far.
Non-perturbative aspects of nonlinear sigma models
Energy Technology Data Exchange (ETDEWEB)
Flore, Raphael
2012-12-07
The aim of this thesis was the study and further development of non-perturbative methods of quantum field theory by means of their application to nonlinear sigma models. While a large part of the physical phenomena of quantum field theory can be successfully predicted by the perturbation theory, some aspects in the region of large coupling strengths are not definitively understood and require suited non-perturbative methods for its analysis. This thesis is concentrated on two approaches, the numerical treatment of field theories on discrete space-time lattices and the functional renormalization group (FRG) as description of the renormalization flux of effective actions. Considerations of the nonlinear O(N) models have shown that for the correct analysis of the critical properties in the framework of the FRG an approach must be chosen, which contained fourth-derivation orders. For this a covariant formalism was developed, which is based on a background-field expansion and the development of a heat kernel. Apart from a destabilizing coupling the results suggest a nontrivial fixed point and by this a non-perturbative renormalizability of these models. The resulting flow diagrams were finally still compared with the results of a numerical analysis of the renormalization flow by means of the Monte-Carlo renormalization group, and hereby qualitative agreement was found. Furthermore an alternative formulation of the FRG in phase-space coordinates was studied and their consistency tested on simple examples. Beyond this an alternative expansion of the effective action in orders of the canonical momenta was applied to the nonlinear O(N) models with the result of a stable non-trivial fixed point, the critical properties of which however show not the expected N-dependence. By means of the FRG finally still the renormalization of topological operators was studied by means of the winding number of the O(3){approx_equal}CP{sup 1} model. By the generalization of the topological
Non-perturbative aspects of nonlinear sigma models
International Nuclear Information System (INIS)
Flore, Raphael
2012-01-01
The aim of this thesis was the study and further development of non-perturbative methods of quantum field theory by means of their application to nonlinear sigma models. While a large part of the physical phenomena of quantum field theory can be successfully predicted by the perturbation theory, some aspects in the region of large coupling strengths are not definitively understood and require suited non-perturbative methods for its analysis. This thesis is concentrated on two approaches, the numerical treatment of field theories on discrete space-time lattices and the functional renormalization group (FRG) as description of the renormalization flux of effective actions. Considerations of the nonlinear O(N) models have shown that for the correct analysis of the critical properties in the framework of the FRG an approach must be chosen, which contained fourth-derivation orders. For this a covariant formalism was developed, which is based on a background-field expansion and the development of a heat kernel. Apart from a destabilizing coupling the results suggest a nontrivial fixed point and by this a non-perturbative renormalizability of these models. The resulting flow diagrams were finally still compared with the results of a numerical analysis of the renormalization flow by means of the Monte-Carlo renormalization group, and hereby qualitative agreement was found. Furthermore an alternative formulation of the FRG in phase-space coordinates was studied and their consistency tested on simple examples. Beyond this an alternative expansion of the effective action in orders of the canonical momenta was applied to the nonlinear O(N) models with the result of a stable non-trivial fixed point, the critical properties of which however show not the expected N-dependence. By means of the FRG finally still the renormalization of topological operators was studied by means of the winding number of the O(3)≅CP 1 model. By the generalization of the topological operator and the
Simulating QCD at the physical point with Nf=2 Wilson twisted mass fermions at maximal twist
International Nuclear Information System (INIS)
Abdel-Rehim, A.; Alexandrou, C.; Cyprus Univ. Nicosia; Burger, F.
2015-12-01
We present simulations of QCD using N f =2 dynamical Wilson twisted mass lattice QCD with physical value of the pion mass and at one value of the lattice spacing. Such simulations at a∼0.09 fm became possible by adding the clover term to the action. While O(a) improvement is still guaranteed by Wilson twisted mass fermions at maximal twist, the introduction of the clover term reduces O(a 2 ) cutoff effects related to isospin symmetry breaking. We give results for a set of phenomenologically interesting observables like pseudo-scalar masses and decay constants, quark masses and the anomalous magnetic moments of leptons. We mostly find remarkably good agreement with phenomenology, even though we cannot take the continuum and thermodynamic limits.
Exact results for Wilson loops in arbitrary representations
Energy Technology Data Exchange (ETDEWEB)
Fiol, Bartomeu; Torrents, Genís [Departament de Física Fonamental i Institut de Ciències del Cosmos, Universitat de Barcelona,Martí i Franquès 1, 08028 Barcelona, Catalonia (Spain)
2014-01-08
We compute the exact vacuum expectation value of 1/2 BPS circular Wilson loops of N=4 U(N) super Yang-Mills in arbitrary irreducible representations. By localization arguments, the computation reduces to evaluating certain integrals in a Gaussian matrix model, which we do using the method of orthogonal polynomials. Our results are particularly simple for Wilson loops in antisymmetric representations; in this case, we observe that the final answers admit an expansion where the coefficients are positive integers, and can be written in terms of sums over skew Young diagrams. As an application of our results, we use them to discuss the exact Bremsstrahlung functions associated to the corresponding heavy probes.
Nonperturbative calculation of symmetry breaking in quantum field theory
Bender, Carl M.; Milton, Kimball A.
1996-01-01
A new version of the delta expansion is presented, which, unlike the conventional delta expansion, can be used to do nonperturbative calculations in a self-interacting scalar quantum field theory having broken symmetry. We calculate the expectation value of the scalar field to first order in delta, where delta is a measure of the degree of nonlinearity in the interaction term.
Baryon Regge trajectories from the area-law of Wilson loop
International Nuclear Information System (INIS)
Simonov, Yu.A.
1989-01-01
In the proper-time path integral representation of the three-quark Green function, baryon masses are calculated for large angular momenta L. Dynamics is given by vacuum background fields in the Wilson loop. Assuming an area law for large Wilson loops one obtains linear baryon Regge trajectories with the same slope as for mesons. For large L the baryon has an asymmetric structure of the quark-diquark type. Dynamic masses of the quark and diquark are generated, which grow with L. 8 refs
3-loop heavy flavor Wilson coefficients in deep-inelastic scattering
International Nuclear Information System (INIS)
Ablinger, J.; Hasselhuhn, A.; Schneider, C.; Manteuffel, A. von
2014-09-01
We present our most recent results on the calculation of the heavy flavor contributions to deep-inelastic scattering at 3-loop order in the large Q 2 limit, where the heavy flavor Wilson coefficients are known to factorize into light flavor Wilson coefficients and massive operator matrix elements. We describe the different techniques employed for the calculation and show the results in the case of the heavy flavor non-singlet and pure singlet contributions to the structure function F 2 (x,Q 2 ).
[Wilson disease. A case report and review of the literature].
Alva-Moncayo, Edith; Castro-Tarín, María; González-Serrano, Adolfo
2011-01-01
Wilson disease is a problem of cuprum metabolism, with recesive autosomic hereditary transmission and a prevalence of one in 30,000 habitants. The cuprum is deposit in a progressive and irreversible way in the liver and encephalus and it is not liberated with quelant treatment. Neurological manifestations are tremor, disartria, extrapiramidal manifestations or distonia. Ophthalmic exploration shows corneal limb with sign of Kayser-Fleischer. a 15-year-old masculine patient with previous hepatitis outbreak in two times. During the last year he presented distonia, bradicinecious, stiffness and indifference with ictericia. Ophthalmological examination reported Kayser-Fleisher rings. Magnetic resonance of brain showed high dense images in lenticular, pallidus globe and caudate nucleus suggestive of Wilson disease. Ceruloplasmin concentration, cuprum in the liver biopsy confirmed the diagnosis. the importance of the case was the hepatic initial manifestations and two years after presented with inexpressive face, and it was considered a psychiatric disease, but the neurological evaluation and the liver biopsy confirmed the diagnosis of Wilson disease.
Low-energy effective action in nonperturbative electrodynamics in curved space-time
International Nuclear Information System (INIS)
Avramidi, Ivan G.; Fucci, Guglielmo
2009-01-01
We study the heat kernel for the Laplace-type partial differential operator acting on smooth sections of a complex spin-tensor bundle over a generic n-dimensional Riemannian manifold. Assuming that the curvature of the U(1) connection (that we call the electromagnetic field) is constant, we compute the first two coefficients of the nonperturbative asymptotic expansion of the heat kernel which are of zero and the first order in Riemannian curvature and of arbitrary order in the electromagnetic field. We apply these results to the study of the effective action in nonperturbative electrodynamics in four dimensions and derive a generalization of the Schwinger's result for the creation of scalar and spinor particles in electromagnetic field induced by the gravitational field. We discover a new infrared divergence in the imaginary part of the effective action due to the gravitational corrections, which seems to be a new physical effect.
Non-perturbative Debye mass in finite-T QCD
Kajantie, Keijo; Peisa, J; Rajantie, A; Rummukainen, K; Shaposhnikov, Mikhail E
1997-01-01
Employing a non-perturbative gauge invariant definition of the Debye screening mass m_D in the effective field theory approach to finite T QCD, we use 3d lattice simulations to determine the leading O(g^2) and to estimate the next-to-leading O(g^3) corrections to m_D in the high temperature region. The O(g^2) correction is large and modifies qualitatively the standard power-counting hierarchy picture of correlation lengths in high temperature QCD.
Arthropod prey of Wilson's Warblers in the understory of Douglas-fir forests
Hagar, J.C.; Dugger, K.M.; Starkey, E.E.
2007-01-01
Availability of food resources is an important factor in avian habitat selection. Food resources for terrestrial birds often are closely related to vegetation structure and composition. Identification of plant species important in supporting food resources may facilitate vegetation management to achieve objectives for providing bird habitat. We used fecal analysis to describe the diet of adult Wilson's Warblers (Wilsonia pusilla) that foraged in the understory of Douglas-fir (Pseudotsuga menziesii) forests in western Oregon during the breeding season. We sampled arthropods at the same sites where diet data were collected, and compared abundance and biomass of prey among seven common shrub species. Wilson's Warblers ate more caterpillars (Lepidoptera larvae), flies (Diptera), beetles (Coleoptera), and Homoptera than expected based on availability. Deciduous shrubs supported higher abundances of arthropod taxa and size classes used as prey by Wilson's Warblers than did evergreen shrubs. The development and maintenance of deciduous understory vegetation in conifer forests of the Pacific Northwest may be fundamental for conservation of food webs that support breeding Wilson's Warblers and other shrub-associated, insectivorous songbirds.
Open Wilson lines and generalized star product in noncommutative scalar field theories
International Nuclear Information System (INIS)
Kiem, Youngjai; Sato, Haru-Tada; Rey, Soo-Jong; Yee, Jung-Tay
2002-01-01
Open Wilson line operators and a generalized star product have been studied extensively in noncommutative gauge theories. We show that they also show up in noncommutative scalar field theories as universal structures. We first point out that the dipole picture of noncommutative geometry provides an intuitive argument for the robustness of the open Wilson lines and generalized star products therein. We calculate the one-loop effective action of noncommutative scalar field theory with a cubic self-interaction and show explicitly that the generalized star products arise in the nonplanar part. It is shown that, at the low-energy, large noncommutativity limit, the nonplanar part is expressible solely in terms of the scalar open Wilson line operator and descendants
Non-perturbative plaquette in 3d pure SU(3)
Hietanen, A; Laine, Mikko; Rummukainen, K; Schröder, Y
2005-01-01
We present a determination of the elementary plaquette and, after the subsequent ultraviolet subtractions, of the finite part of the gluon condensate, in lattice regularization in three-dimensional pure SU(3) gauge theory. Through a change of regularization scheme to MSbar and a matching back to full four-dimensional QCD, this result determines the first non-perturbative contribution in the weak-coupling expansion of hot QCD pressure.
Symmetries of Ginsparg-Wilson chiral fermions
International Nuclear Information System (INIS)
Mandula, Jeffrey E.
2009-01-01
The group structure of the variant chiral symmetry discovered by Luescher in the Ginsparg-Wilson description of lattice chiral fermions is analyzed. It is shown that the group contains an infinite number of linearly independent symmetry generators, and the Lie algebra is given explicitly. CP is an automorphism of this extended chiral group, and the CP transformation properties of the symmetry generators are found. The group has an infinite-parameter invariant subgroup, and the factor group, whose elements are its cosets, is isomorphic to the continuum chiral symmetry group. Features of the currents associated with these symmetries are discussed, including the fact that some different, noncommuting symmetry generators lead to the same Noether current. These are universal features of lattice chiral fermions based on the Ginsparg-Wilson relation; they occur in the overlap, domain-wall, and perfect-action formulations. In a solvable example, free overlap fermions, these noncanonical elements of lattice chiral symmetry are related to complex energy singularities that violate reflection positivity and impede continuation to Minkowski space.
3-loop heavy flavor Wilson coefficients in deep-inelastic scattering
Energy Technology Data Exchange (ETDEWEB)
Ablinger, J.; Hasselhuhn, A.; Schneider, C. [Johannes-Kepler-Univ. Linz (Austria). RISC; Behring, A.; Bluemlein, J.; Freitas, A. de; Raab, C.; Round, M. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Manteuffel, A. von [Mainz Univ. (Germany). PRISMA Cluster of Excellence; Wissbrock, F. [Johannes-Kepler-Univ. Linz (Austria). RISC; Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); IHES Institut des Hautes Etudes Scientifiques, Bures-sur-Yvette (France)
2014-09-15
We present our most recent results on the calculation of the heavy flavor contributions to deep-inelastic scattering at 3-loop order in the large Q{sup 2} limit, where the heavy flavor Wilson coefficients are known to factorize into light flavor Wilson coefficients and massive operator matrix elements. We describe the different techniques employed for the calculation and show the results in the case of the heavy flavor non-singlet and pure singlet contributions to the structure function F{sub 2}(x,Q{sup 2}).
Nonperturbative correction to the threshold production of t anti t-pairs
International Nuclear Information System (INIS)
Fadin, V.S.; Yakovlev, O.I.
1991-01-01
Calculations are performed of the nonperturbative correction to the cross-section for the tt-pair near the threshold in e + e - -annihilation, which is connected with the existence of a gluon condensate. These have been made using a constant chromoelectric field approximation. 15 refs
Non-perturbative subtractions in the heavy quark effective field theory
International Nuclear Information System (INIS)
Maiani, L.; Martinelli, G.; Sachrajda, C.T.
1992-01-01
We demonstrate the presence of ultraviolet power divergences in the O(1/m h ) corrections to matrix elements of hadronic operators containing a heavy quark field (where m h is the mass of the heavy quark). These power divergences must be subtracted non-perturbatively. The implications for lattice computations are discussed in detail. (orig.)
Epidemiology and introduction to the clinical presentation of Wilson disease.
Lo, Christine; Bandmann, Oliver
2017-01-01
Our understanding of the epidemiology of Wilson disease has steadily grown since Sternlieb and Scheinberg's first prevalence estimate of 5 per million individuals in 1968. Increasingly sophisticated genetic techniques have led to revised genetic prevalence estimates of 142 per million. Various population isolates exist where the prevalence of Wilson disease is higher still, the highest being 885 per million from within the mountainous region of Rucar in Romania. In Sardinia, where the prevalence of Wilson disease has been calculated at 370 per million births, six mutations account for around 85% of Wilson disease chromosomes identified. Significant variation in the patterns of presentation may however exist, even between individuals carrying the same mutations. At either extremes of presentation are an 8-month-old infant with abnormal liver function tests and individuals diagnosed in their eighth decade of life. Three main patterns of presentation have been recognized - hepatic, neurologic, and psychiatric - prompting their presentation to a diverse range of specialists. Deviations in the family history from the anticipated autosomal-recessive mode of inheritance, with apparent "pseudodominance" and mechanisms of inheritance that include uniparental isodisomy (the inheritance of both chromosomal copies from a single parent), may all further cloud the diagnosis. It can therefore take the efforts of an astute clinician with a high clinical index of suspicion to clinch the diagnosis of this eminently treatable condition. © 2017 Elsevier B.V. All rights reserved.
MRI manifestation of Wilson's disease accompanied with central pontine myelinolysis
International Nuclear Information System (INIS)
Zhang Jingsong; Huan Yi; Chang Yingjuan; Chang Yingjuan; Ge Yali; Zhang Guangyun; Han Yuedong; Zhao Haitao; Yang Chunmin; Yang Yan
2004-01-01
Objective: To discuss MRI manifestation of Wilson's disease accompanied with central pontine myelinolysis (CPM), and to especially detect the value of diffusion-weighted MRI (DWI) in this disease. Methods: Two cases of Wilson's disease accompanied with CPM were performed with sequent MR examination including T 1 WI, T 2 WI, FLAIR, DWI, and contrast-enhanced MRI (CE MRI) by a 1.5 T magnetic resonance system (Philips gyroscan master). Results: Symmetric long T 1 and T 2 signals were found in central pontine region, lenticular nucleus, caudate nucleus, and thalamus. CEMRI showed no apparent enhanced lesions. DWI showed obviously high signal intensities in central pontine region with apparent diffusion coefficient values fluctuated between (100-300) x 10 -6 mm 2 /s while FLAIR images just showed slightly high signal in the same area, which suggested that cytotoxic edema did in fact exist in CPM. Meanwhile, DWI also showed high signals in bilateral lenticular nucleus with apparent diffusion coefficient values fluctuated between (300-600) x 10 -6 mm 2 /s, however, FLAIR images showed heterogeneous high signals and one case presented low DWI signals in bilateral head of caudate nucleus, all these signs might be explained by mixed-changes of cytotoxic edema and vasogenic edema in long period of Wilson's disease. Conclusion: Wilson's disease and CPM have characteristic MRI manifestation and DWI may be a very useful way to confirm a correct diagnosis. (authors)
Topological susceptibility in lattice QCD with unimproved Wilson fermions
International Nuclear Information System (INIS)
Chowdhury, Abhishek; De, Asit K.; De Sarkar, Sangita; Harindranath, A.; Mondal, Santanu; Sarkar, Anwesa; Maiti, Jyotirmoy
2012-01-01
We address a long standing problem regarding topology in lattice simulations of QCD with unimproved Wilson fermions. Earlier attempt with unimproved Wilson fermions at β=5.6 to verify the suppression of topological susceptibility with decreasing quark mass (m q ) was unable to unambiguously confirm the suppression. We carry out systematic calculations for two degenerate flavours at two different lattice spacings (β=5.6 and 5.8). The effects of quark mass, lattice volume and the lattice spacing on the spanning of different topological sectors are presented. We unambiguously demonstrate the suppression of the topological susceptibility with decreasing quark mass, expected from chiral Ward identity and chiral perturbation theory.
The epsilon regime of chiral perturbation theory with Wilson-type fermions
Energy Technology Data Exchange (ETDEWEB)
Jansen, K. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Shindler, A. [Liverpool Univ. (United Kingdom). Theoretical Physics Division
2009-11-15
In this proceeding contribution we report on the ongoing effort to simulate Wilson-type fermions in the so called epsilon regime of chiral perturbation theory (cPT).We present results for the chiral condensate and the pseudoscalar decay constant obtained with Wilson twisted mass fermions employing two lattice spacings, two different physical volumes and several quark masses. With this set of simulations we make a first attempt to estimate the systematic uncertainties. (orig.)
The epsilon regime of chiral perturbation theory with Wilson-type fermions
International Nuclear Information System (INIS)
Jansen, K.; Shindler, A.
2009-11-01
In this proceeding contribution we report on the ongoing effort to simulate Wilson-type fermions in the so called epsilon regime of chiral perturbation theory (cPT).We present results for the chiral condensate and the pseudoscalar decay constant obtained with Wilson twisted mass fermions employing two lattice spacings, two different physical volumes and several quark masses. With this set of simulations we make a first attempt to estimate the systematic uncertainties. (orig.)
Chen, Hongming; Carlsson, Lars; Eriksson, Mats; Varkonyi, Peter; Norinder, Ulf; Nilsson, Ingemar
2013-06-24
A novel methodology was developed to build Free-Wilson like local QSAR models by combining R-group signatures and the SVM algorithm. Unlike Free-Wilson analysis this method is able to make predictions for compounds with R-groups not present in a training set. Eleven public data sets were chosen as test cases for comparing the performance of our new method with several other traditional modeling strategies, including Free-Wilson analysis. Our results show that the R-group signature SVM models achieve better prediction accuracy compared with Free-Wilson analysis in general. Moreover, the predictions of R-group signature models are also comparable to the models using ECFP6 fingerprints and signatures for the whole compound. Most importantly, R-group contributions to the SVM model can be obtained by calculating the gradient for R-group signatures. For most of the studied data sets, a significant correlation with that of a corresponding Free-Wilson analysis is shown. These results suggest that the R-group contribution can be used to interpret bioactivity data and highlight that the R-group signature based SVM modeling method is as interpretable as Free-Wilson analysis. Hence the signature SVM model can be a useful modeling tool for any drug discovery project.
Nonperturbative determination of the QCD potential at O(1/m)
International Nuclear Information System (INIS)
Koma, Y.; Koma, M.; Wittig, H.
2006-07-01
The relativistic correction to the QCD static inter-quark potential at O(1/m) is investigated nonperturbatively for the first time by using lattice Monte Carlo QCD simulations. The correction is found to be comparable with the Coulombic term of the static potential when applied to charmonium, and amounts to 26% of the Coulombic term for bottomonium. (Orig.)
(Non)perturbative gravity, nonlocality, and nice slices
International Nuclear Information System (INIS)
Giddings, Steven B.
2006-01-01
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
Non-perturbative approach to 2D-supergravity and super-Virasoro constraints
Becker, M
1994-01-01
The coupling of N=1 SCFT of type (4m,2) to two-dimensional supergravity can be formulated non-perturbatively in terms of a discrete super-eigenvalue model proposed by Alvarez-Gaum\\'e, et al. We derive the superloop equations that describe, in the double scaling limit, the non-perturbative solution of this model. These equations are equivalent to the double scaled super-Virasoro constraints satisfied by the partition function. They are formulated in terms of a \\widehat c=1 theory, with a \\IZ_2-twisted scalar field and a Weyl-Majorana fermion in the Ramond sector. We have solved the superloop equations to all orders in the genus expansion and obtained the explicit expressions for the correlation functions of gravitationally dressed scaling operators in the NS- and R-sector. In the double scaling limit, we obtain a formulation of the model in terms of a new supersymmetric extension of the KdV hierarchy.
Abundant families of new traveling wave solutions for the coupled Drinfel'd-Sokolov-Wilson equation
International Nuclear Information System (INIS)
Yao Yuqin
2005-01-01
The generalized Jacobi elliptic function method is further improved by introducing an elliptic function φ(ξ) as a new independent variable and it is easy to calculate the over-determined equations. Abundant new traveling wave solutions of the coupled Drinfel'd-Sokolov-Wilson equation are obtained. The solutions obtained include the kink-shaped solutions, bell-shaped solutions, singular solutions and periodic solutions
van Meer, Suzanne; de Man, Robert A.; van den Berg, Aad P.; Houwen, Roderick H. J.; Linn, Francisca H. H.; van Oijen, Martijn G. H.; Siersema, Peter D.; van Erpecum, Karel J.
Background and AimsData on risk of hepatocellular carcinoma (HCC) in patients with Wilson disease are scarce. We determine HCC risk in a well-defined cohort of Wilson patients. MethodsAll patients with a confirmed diagnosis of Wilson disease (Leipzig score4) in three Dutch university referral
Wilson loops in 5d $\\mathcal{N}=1$ theories and S-duality arXiv
Assel, Benjamin
We study the action of S-duality on half-BPS Wilson loop operators in 5d $\\mathcal{N}=1$ theories. The duality is the statement that different massive deformations of a single 5d SCFT are described by different gauge theories, or equivalently that the SCFT points in parameter space of two gauge theories coincide. The pairs of dual theories that we study are realized by brane webs in type IIB string theory that are S-dual to each other. We focus on $SU(2)$ SQCD theories with $N_f \\le 4$ flavors, which are self-dual, and on $SU(3)$ SQCD theories, which are dual to $SU(2)^2$ quiver theories. From string theory engineering we predict that Wilson loops are mapped to dual Wilson loops under S-duality. We confirm the predictions with exact computations of Wilson loop VEVs, which we extract from the 5d half-index in the presence of auxiliary loop operators (also known as higher qq-characters) sourced by D3 branes placed in the brane webs. A special role is played by Wilson loops in tensor products of the (anti)fundam...
A non-perturbative study of 4d U(1) non-commutative gauge theory - the fate of one-loop instability
International Nuclear Information System (INIS)
Bietenholz, Wolfgang; Nishimura, Jun; Susaki, Yoshiaki; Volkholz, Jan
2006-01-01
Recent perturbative studies show that in 4d non-commutative spaces, the trivial (classically stable) vacuum of gauge theories becomes unstable at the quantum level, unless one introduces sufficiently many fermionic degrees of freedom. This is due to a negative IR-singular term in the one-loop effective potential, which appears as a result of the UV/IR mixing. We study such a system non-perturbatively in the case of pure U(1) gauge theory in four dimensions, where two directions are non-commutative. Monte Carlo simulations are performed after mapping the regularized theory onto a U(N) lattice gauge theory in d = 2. At intermediate coupling strength, we find a phase in which open Wilson lines acquire non-zero vacuum expectation values, which implies the spontaneous breakdown of translational invariance. In this phase, various physical quantities obey clear scaling behaviors in the continuum limit with a fixed non-commutativity parameter θ, which provides evidence for a possible continuum theory. The extent of the dynamically generated space in the non-commutative directions becomes finite in the above limit, and its dependence on θ is evaluated explicitly. We also study the dispersion relation. In the weak coupling symmetric phase, it involves a negative IR-singular term, which is responsible for the observed phase transition. In the broken phase, it reveals the existence of the Nambu-Goldstone mode associated with the spontaneous symmetry breaking
Nambu-Jona-Lasinio model with Wilson fermions
DEFF Research Database (Denmark)
Rantaharju, Jarno; Drach, Vincent; Pica, Claudio
2017-01-01
We present a lattice study of a Nambu-Jona-Lasinio (NJL) model using Wilson fermions. Four-fermion interactions are a natural part of several extensions of the Standard Model, appearing as a low-energy description of a more fundamental theory. In models of dynamical electroweak symmetry breaking...
Energy-momentum tensor correlation function in Nf = 2 + 1 full QCD at finite temperature
Taniguchi, Yusuke; Ejiri, Shinji; Kanaya, Kazuyuki; Kitazawa, Masakiyo; Suzuki, Asobu; Suzuki, Hiroshi; Umeda, Takashi
2018-03-01
We measure correlation functions of the nonperturbatively renormalized energy-momentum tensor in Nf = 2 + 1 full QCD at finite temperature by applying the gradient flow method both to the gauge and quark fields. Our main interest is to study the conservation law of the energy-momentum tensor and to test whether the linear response relation is properly realized for the entropy density. By using the linear response relation we calculate the specific heat from the correlation function. We adopt the nonperturba-tively improved Wilson fermion and Iwasaki gauge action at a fine lattice spacing = 0:07 fm. In this paper the temperature is limited to a single value T ≃ 232 MeV. The u, d quark mass is rather heavy with mπ=mρ ≃ 0:63 while the s quark mass is set to approximately its physical value.
The Observatory as Laboratory: Spectral Analysis at Mount Wilson Observatory
Brashear, Ronald
2018-01-01
This paper will discuss the seminal changes in astronomical research practices made at the Mount Wilson Observatory in the early twentieth century by George Ellery Hale and his staff. Hale’s desire to set the agenda for solar and stellar astronomical research is often described in terms of his new telescopes, primarily the solar tower observatories and the 60- and 100-inch telescopes on Mount Wilson. This paper will focus more on the ancillary but no less critical parts of Hale’s research mission: the establishment of associated “physical” laboratories as part of the observatory complex where observational spectral data could be quickly compared with spectra obtained using specialized laboratory equipment. Hale built a spectroscopic laboratory on the mountain and a more elaborate physical laboratory in Pasadena and staffed it with highly trained physicists, not classically trained astronomers. The success of Hale’s vision for an astronomical observatory quickly made the Carnegie Institution’s Mount Wilson Observatory one of the most important astrophysical research centers in the world.
Parton densities in quantum chromodynamics gauge invariance, path-dependence and Wilson lines
Cherednikov, Igor O
2016-01-01
The purpose of this book is to give a systematic pedagogical exposition of the quantitative analysis of Wilson lines and loops in quantum chromodynamics. Using techniques from the previous volume (Wilson Lines in Quantum Field Theory, 2014), ab initio techniques are developed and practical tools for their implementation presented. An emphasis is put on their renormalization and on implications on processes observable at experimental facilities.
Symmetries of Maldacena-Wilson loops from integrable string theory
International Nuclear Information System (INIS)
Muenkler, Hagen
2017-01-01
This thesis discusses hidden symmetries within N=4 supersymmetric Yang-Mills theory or its AdS/CFT dual, string theory in AdS 5 x S 5 . Here, we focus on the Maldacena-Wilson loop, which is a suitable object for this study since its vacuum expectation value is finite for smooth contours and the conjectured duality to scattering amplitudes provides a conceptual path to transfer its symmetries to other observables. Its strong-coupling description via minimal surfaces in AdS 5 allows to construct the symmetries from the integrability of the underlying classical string theory. This approach has been utilized before to derive a strong-coupling Yangian symmetry of the Maldacena-Wilson loop and describe equiareal deformations of minimal surfaces in AdS 3 . These two findings are connected and extended in the present thesis. In order to discuss the symmetries systematically, we first discuss the symmetry structure of the underlying string model. The discussion can be generalized to the discussion of generic symmetric space models. For these, we find that the symmetry which generates the equiareal deformations of minimal surfaces in AdS 3 has a central role in the symmetry structure of the model: It acts as a raising operator on the infinite tower of conserved charges, thus generating the spectral parameter, and can be employed to construct all symmetry variations from the global symmetry of the model. It is thus referred to as the master symmetry of symmetric space models. Additionally, the algebra of the symmetry variations and the conserved charges is worked out. For the concrete case of minimal surfaces in AdS 5 , we discuss the deformation of the four-cusp solution, which provides the dual description of the four-gluon scattering amplitude. This marks the first step toward transferring the master symmetry to scattering amplitudes. Moreover, we compute the master and Yangian symmetry variations of generic, smooth boundary curves. The results leads to a coupling
Symmetries of Maldacena-Wilson loops from integrable string theory
Energy Technology Data Exchange (ETDEWEB)
Muenkler, Hagen
2017-09-11
This thesis discusses hidden symmetries within N=4 supersymmetric Yang-Mills theory or its AdS/CFT dual, string theory in AdS{sub 5} x S{sup 5}. Here, we focus on the Maldacena-Wilson loop, which is a suitable object for this study since its vacuum expectation value is finite for smooth contours and the conjectured duality to scattering amplitudes provides a conceptual path to transfer its symmetries to other observables. Its strong-coupling description via minimal surfaces in AdS{sub 5} allows to construct the symmetries from the integrability of the underlying classical string theory. This approach has been utilized before to derive a strong-coupling Yangian symmetry of the Maldacena-Wilson loop and describe equiareal deformations of minimal surfaces in AdS{sub 3}. These two findings are connected and extended in the present thesis. In order to discuss the symmetries systematically, we first discuss the symmetry structure of the underlying string model. The discussion can be generalized to the discussion of generic symmetric space models. For these, we find that the symmetry which generates the equiareal deformations of minimal surfaces in AdS{sub 3} has a central role in the symmetry structure of the model: It acts as a raising operator on the infinite tower of conserved charges, thus generating the spectral parameter, and can be employed to construct all symmetry variations from the global symmetry of the model. It is thus referred to as the master symmetry of symmetric space models. Additionally, the algebra of the symmetry variations and the conserved charges is worked out. For the concrete case of minimal surfaces in AdS{sub 5}, we discuss the deformation of the four-cusp solution, which provides the dual description of the four-gluon scattering amplitude. This marks the first step toward transferring the master symmetry to scattering amplitudes. Moreover, we compute the master and Yangian symmetry variations of generic, smooth boundary curves. The results
Inhibitory rTMS applied on somatosensory cortex in Wilson's disease patients with hand dystonia.
Lozeron, Pierre; Poujois, Aurélia; Meppiel, Elodie; Masmoudi, Sana; Magnan, Thierry Peron; Vicaut, Eric; Houdart, Emmanuel; Guichard, Jean-Pierre; Trocello, Jean-Marc; Woimant, France; Kubis, Nathalie
2017-10-01
Hand dystonia is a common complication of Wilson's disease (WD), responsible for handwriting difficulties and disability. Alteration of sensorimotor integration and overactivity of the somatosensory cortex have been demonstrated in dystonia. This study investigated the immediate after effect of an inhibitory repetitive transcranial magnetic stimulation (rTMS) applied over the somatosensory cortex on the writing function in WD patients with hand dystonia. We performed a pilot prospective randomized double-blind sham-controlled crossover rTMS study. A 20-min 1-Hz rTMS session, stereotaxically guided, was applied over the left somatosensory cortex in 13 WD patients with right dystonic writer's cramp. After 3 days, each patient was crossed-over to the alternative treatment. Patients were clinically evaluated before and immediately after each rTMS session with the Unified Wilson's Disease rating scale (UWDRS), the Writers' Cramp Rating Scale (WCRS), a specifically designed scale for handwriting difficulties in Wilson's disease patients (FAR, flow, accuracy, and rhythmicity evaluation), and a visual analog scale (VAS) for handwriting discomfort. No significant change in UWDRS, WCRS, VAS, or FAR scores was observed in patients treated with somatosensory inhibitory rTMS compared to the sham protocol. The FAR negatively correlated with UWDRS (r = -0.6; P = 0.02), but not with the WCRS score, disease duration, MRI diffusion lesions, or with atrophy scores. In our experimental conditions, a single inhibitory rTMS session applied over somatosensory cortex did not improve dystonic writer cramp in WD patients.
Hadron masses and decay constants with Wilson quarks at β=5.85 and 6.0
International Nuclear Information System (INIS)
Anon.
1996-01-01
We present results of a high statistics calculation of hadron masses and meson decay constants in the quenched approximation to lattice QCD with Wilson quarks at β= 5.85 and 6.0 on 24 3 x54 lattices. We analyze the data paying attention in particular to the systematic errors due to the choice of fitting range and due to the contamination from excited states. We find that the systematic errors for the hadron masses with quarks lighter than the strange quark amount to 1 to 2 times the statistical errors. When the lattice scale is fixed from the ρ meson mass, the masses of the Ω - baryon and the φ meson at two β close-quote s agree with experiment within about one standard deviation. On the other hand, the central value of the nucleon mass at β=6.0 (5.85) is larger than its experimental value by about 15% (20%) and that of the Δ mass by about 15% (4%): Even when the systematic errors are included, the baryon masses at β=6.0 do not agree with experiment. Vector meson decay constants at two values of β agree well with each other and are consistent with experiment for a wide range of the quark mass, when we use current renormalization constants determined nonperturbatively by numerical simulations. The pion decay constant agrees with experiment albeit with large errors. Results for the masses of excited states of the ρ meson and the nucleon are also presented. copyright 1996 The American Physical Society
Diverse Functional Properties of Wilson Disease ATP7B Variants
Huster, Dominik; Kühne, Angelika; Bhattacharjee, Ashima; Raines, Lily; Jantsch, Vanessa; Noe, Johannes; Schirrmeister, Wiebke; Sommerer, Ines; Sabri, Osama; Berr, Frieder; Mössner, Joachim; Stieger, Bruno; Caca, Karel; Lutsenko, Svetlana
2012-01-01
BACKGROUND & AIMS Wilson disease is a severe disorder of copper metabolism caused by mutations in ATP7B, which encodes a copper-transporting adenosine triphosphatase. The disease presents with a variable phenotype that complicates the diagnostic process and treatment. Little is known about the mechanisms that contribute to the different phenotypes of the disease. METHODS We analyzed 28 variants of ATP7B from patients with Wilson disease that affected different functional domains; the gene products were expressed using the baculovirus expression system in Sf9 cells. Protein function was analyzed by measuring catalytic activity and copper (64Cu) transport into vesicles. We studied intracellular localization of variants of ATP7B that had measurable transport activities and were tagged with green fluorescent protein in mammalian cells using confocal laser scanning microscopy. RESULTS Properties of ATP7B variants with pathogenic amino-acid substitution varied greatly even if substitutions were in the same functional domain. Some variants had complete loss of catalytic and transport activity, whereas others lost transport activity but retained phosphor-intermediate formation or had partial losses of activity. In mammalian cells, transport-competent variants differed in stability and subcellular localization. CONCLUSIONS Variants in ATP7B associated with Wilson disease disrupt the protein’s transport activity, result in its mislocalization, and reduce its stability. Single assays are insufficient to accurately predict the effects of ATP7B variants the function of its product and development of Wilson disease. These findings will contribute to our understanding of genotype–phenotype correlation and mechanisms of disease pathogenesis. PMID:22240481
Ruth, J.M.; Stanley, T.R.
2002-01-01
We studied Wilson's Warbler (Wilsonia pusilla) and Yellow Warbler (Dendroica petechia) habitat use in allopatric and sympatric populations in the Rocky Mountains of northern Colorado and southeastern Wyoming in order to better understand the different habitat needs and interactions of these two species. Foraging Wilson's Warblers and Yellow Warblers used very similar habitat, both selecting larger, more open shrubs. In spite of similar foraging habitat, comparisons of habitat use by the two species at the sympatric sites yielded no evidence of foraging habitat partitioning or exclusion. There was evidence of nesting habitat partitioning. Wilson's Warblers nested on the ground, with some evidence that they used smaller, more densely stemmed shrubs under which to nest. Yellow Warblers are shrub nesters and selected larger, more open shrubs in which to nest. Results provide no evidence that Yellow Warblers can be blamed for population declines in Wilson's Warblers.
Notes on winter feeding behavior and molt in Wilson's phalaropes
Burger, J.; Howe, M.
1975-01-01
Wilson's Phalaropes, Steganopus tricolor, migrate in late summer from the prairie regions of North America to their wintering grounds in the highlands of Peru and the inland and coastal waters of Chile, Bolivia, Paraguay, Uruguay, and Argentina (Holmes 1939, Meyer de Schauensee 1970). Reports on these birds from their wintering habitat are few. This paper describes numbers, feeding behavior, and molt of Wilson's Phalaropes wintering in a freshwater marsh in central Argentina. Fieldwork in Argentina was conducted by the senior author. The junior author analyzed molt patterns of birds collected there and added data he collected in North Dakota in 1968 and 1969.
Gluon Green functions free of quantum fluctuations
Directory of Open Access Journals (Sweden)
A. Athenodorou
2016-09-01
Full Text Available This letter reports on how the Wilson flow technique can efficaciously kill the short-distance quantum fluctuations of 2- and 3-gluon Green functions, remove the ΛQCD scale and destroy the transition from the confining non-perturbative to the asymptotically-free perturbative sector. After the Wilson flow, the behavior of the Green functions with momenta can be described in terms of the quasi-classical instanton background. The same behavior also occurs, before the Wilson flow, at low-momenta. This last result permits applications as, for instance, the detection of instanton phenomenological properties or a determination of the lattice spacing only from the gauge sector of the theory.
Wilson loops, instantons and quantum mechanics
International Nuclear Information System (INIS)
Schiereck, Marc
2014-05-01
In this thesis we examine two different problems. The first is the computation of vacuum expectation values of Wilson loop operators in ABJM theory, the other problem is finding the instanton series of the refined topological string on certain local Calabi-Yau geometries in the Nekrasov-Shatashvili limit. Based on the description of ABJM theory as a matrix model, it is possible to find a description of it in terms of an ideal Fermi gas with a non-trivial one-particle Hamiltonian. The vacuum-expectation-values of Wilson loop operators in ABJM theory correspond to averages of operators in the statistical-mechanical problem. Using the WKB expansion, it is possible to extract the full 1/N expansion of the vevs, up to exponentially small contributions, for arbitrary Chern-Simons coupling. We compute these vevs for the 1/6 and 1/2 BPS Wilson loops at any winding number. These can be written in terms of the Airy function. The expressions we found reproduce the low genus results previously obtained in the 't Hooft expansion. In another problem we use mirror symmetry, quantum geometry and modularity properties of elliptic curves to calculate the refined free energies, given in terms of an instanton sum, in the Nekrasov-Shatashvili limit on non-compact toric Calabi-Yau manifolds, based on del Pezzo surfaces. Quantum geometry here is to be understood as a quantum deformed version of rigid special geometry, which has its origin in the quantum mechanical behavior of branes in the topological string B-model. We argue that in the Seiberg-Witten picture only the Coulomb parameters lead to quantum corrections, while the mass parameters remain uncorrected. In certain cases we also compute the expansion of the free energies at the orbifold point and the conifold locus. We compute the quantum corrections order by order on ℎ by deriving second order differential operators, which act on the classical periods.
Nonperturbative summation over 3D discrete topologies
International Nuclear Information System (INIS)
Freidel, Laurent; Louapre, David
2003-01-01
The group field theories realizing the sum over all triangulations of all topologies of 3D discrete gravity amplitudes are known to be nonuniquely Borel summable. We modify these models to construct a new group field theory which is proved to be uniquely Borel summable, defining in an unambiguous way a nonperturbative sum over topologies in the context of 3D dynamical triangulations and spin foam models. Moreover, we give some arguments to support the fact that, despite our modification, this new model is similar to the original one, and therefore could be taken as a definition of the sum over topologies of 3D quantum gravity amplitudes
The Modern First Lady and Public Policy: From Edith Wilson through Hillary Rodham Clinton.
Black, Allida M.
2001-01-01
Discusses the role in and influence on public policy of twentieth century First Ladies including Edith Roosevelt, Helen Taft, Ellen Wilson, Edith Wilson, Florence Harding, Lou Henry Hoover, Eleanor Roosevelt, Jacqueline Kennedy, Lady Bird Johnson, Rosalynn Carter, Nancy Reagan, Barbara Bush, and Hillary Rodham Clinton. (CMK)
A non-perturbative study of 4d U(1) non-commutative gauge theory — the fate of one-loop instability
Bietenholz, Wolfgang; Nishimura, Jun; Susaki, Yoshiaki; Volkholz, Jan
2006-10-01
Recent perturbative studies show that in 4d non-commutative spaces, the trivial (classically stable) vacuum of gauge theories becomes unstable at the quantum level, unless one introduces sufficiently many fermionic degrees of freedom. This is due to a negative IR-singular term in the one-loop effective potential, which appears as a result of the UV/IR mixing. We study such a system non-perturbatively in the case of pure U(1) gauge theory in four dimensions, where two directions are non-commutative. Monte Carlo simulations are performed after mapping the regularized theory onto a U(N) lattice gauge theory in d = 2. At intermediate coupling strength, we find a phase in which open Wilson lines acquire non-zero vacuum expectation values, which implies the spontaneous breakdown of translational invariance. In this phase, various physical quantities obey clear scaling behaviors in the continuum limit with a fixed non-commutativity parameter θ, which provides evidence for a possible continuum theory. The extent of the dynamically generated space in the non-commutative directions becomes finite in the above limit, and its dependence on θ is evaluated explicitly. We also study the dispersion relation. In the weak coupling symmetric phase, it involves a negative IR-singular term, which is responsible for the observed phase transition. In the broken phase, it reveals the existence of the Nambu-Goldstone mode associated with the spontaneous symmetry breaking.
Comments on exact quantization conditions and non-perturbative topological strings
International Nuclear Information System (INIS)
Hatsuda, Yasuyuki
2015-12-01
We give some remarks on exact quantization conditions associated with quantized mirror curves of local Calabi-Yau threefolds, conjectured in arXiv:1410.3382. It is shown that they characterize a non-perturbative completion of the refined topological strings in the Nekrasov-Shatashvili limit. We find that the quantization conditions enjoy an exact S-dual invariance. We also discuss Borel summability of the semi-classical spectrum.
An Approach to Enforcing Clark-Wilson Model in Role-based Access Control Model
Institute of Scientific and Technical Information of China (English)
LIANGBin; SHIWenchang; SUNYufang; SUNBo
2004-01-01
Using one security model to enforce another is a prospective solution to multi-policy support. In this paper, an approach to the enforcing Clark-Wilson data integrity model in the Role-based access control (RBAC) model is proposed. An enforcement construction with great feasibility is presented. In this construction, a direct way to enforce the Clark-Wilson model is provided, the corresponding relations among users, transformation procedures, and constrained data items are strengthened; the concepts of task and subtask are introduced to enhance the support to least-privilege. The proposed approach widens the applicability of RBAC. The theoretical foundation for adopting Clark-Wilson model in a RBAC system with small cost is offered to meet the requirements of multi-policy support and policy flexibility.
Directory of Open Access Journals (Sweden)
Havlik Jan
2017-01-01
Full Text Available This article deals with the experimental determination of heat transfer coefficients. The calculation of heat transfer coefficients constitutes a crucial issue in design and sizing of heat exchangers. The Wilson plot method and its modifications based on measured experimental data utilization provide an appropriate tool for the analysis of convection heat transfer processes and the determination of convection coefficients in complex cases. A modification of the Wilson plot method for shell-and-tube condensers is proposed. The original Wilson plot method considers a constant value of thermal resistance on the condensation side. The heat transfer coefficient on the cooling side is determined based on the change in thermal resistance for different conditions (fluid velocity and temperature. The modification is based on the validation of the Nusselt theory for calculating the heat transfer coefficient on the condensation side. A change of thermal resistance on the condensation side is expected and the value is part of the calculation. It is possible to improve the determination accuracy of the criterion equation for calculation of the heat transfer coefficient using the proposed modification. The criterion equation proposed by this modification for the tested shell-and-tube condenser achieves good agreement with the experimental results and also with commonly used theoretical methods.
Extensions of the Wilson-Bappu effect among very luminous stars
International Nuclear Information System (INIS)
Stencel, R.E.
1978-01-01
Wilson and Bappu (1957) published their observational correlation of Msub(v) and the logarithm of the full width at half maximum of the CaII K-line central emission for G, K and M stars. The accuracy makes the approach valuable for late-type supergiants since other methods suffer from comparable errors. However, for F through M supergiants (Ia, O), circumstellar absorption obscures the chromospheric K-line core emission and excludes such objects from the Wilson-Bappu correlation. The author reports on a new class of emission lines in late-type giant and supergiant spectra that exhibit Msub(v) correlated widths, yet are detectable among the brightest stars. (Auth.)
SU(3) sextet model with Wilson fermions
DEFF Research Database (Denmark)
Hansen, Martin; Drach, Vincent; Pica, Claudio
2017-01-01
to be inside or very close to the lower boundary of the conformal window. We use the Wilson discretization for the fermions and map the phase structure of the lattice model. We study several spectral and gradient flow observables both in the bulk and the weak coupling phases. While in the bulk phase we find...
A Pade-Aided Analysis of Nonperturbative NN Scattering in 1S0 Channel
International Nuclear Information System (INIS)
Yang Jifeng; Huang Jianhua
2007-01-01
We carried out a Pade approximant analysis on a compact factor of the T-matrix for NN scattering to explore the nonperturbative renormalization prescription in a universal manner. The utilities and virtues for this Pade analysis are discussed.
International Nuclear Information System (INIS)
Ablinger, J.; Hasselhuhn, A.; Schneider, C.; Behring, A.; Bluemlein, J.; Freitas, A. de; Raab, C.; Round, M.; Manteuffel, A. von
2014-07-01
We report on our latest results in the calculation of the three-loop heavy flavor contributions to the Wilson coefficients in deep-inelastic scattering in the asymptotic region Q 2 >>m 2 . We discuss the different methods used to compute the required operator matrix elements and the corresponding Feynman integrals. These methods very recently allowed us to obtain a series of new operator matrix elements and Wilson coefficients like the flavor non-singlet and pure singlet Wilson coefficients.
A nonperturbative fermion-boson vertex
International Nuclear Information System (INIS)
Bashir, A.; Raya, A.
2002-01-01
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 Kizilersue 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 α 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
Preston, George W.
1995-02-01
Congenial, fiercely independent, and firmly grounded in the virtues of experimental science, Olin Wilson was a canny practitioner of the art of the possible in observational astrophysics as it flourished in the middle of the 20th century. He enjoyed a long association with the Astronomical Society of the Pacific as a contributor to its Publications, as President of the Society, and as recipient of its Catherine Wolfe Bruce Medal. By the time he departed, stellar astrophysics had matured and had acquired new dimensions due to Olin's diligence and curiosity. (SECTION: Obituary)
Pion structure from lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Javadi Motaghi, Narjes
2015-05-12
In this thesis we use lattice QCD to compute the second Mellin moments of pion generalized parton distributions and pion electromagnetic form factors. For our calculations we are able to analyze a large set of gauge configurations with 2 dynamical flavours using non-perturbatively the improved Wilson-Sheikholeslami-Wohlert fermionic action pion masses ranging down to 151 MeV. By employing improved smearing we were able to suppress excited state contamination. However, our data in the physical quark mass limit show that some excited state contamination remains. We show the non-zero sink momentum is optimal for the computation of the electromagnetic form factors and generalized form factors at finite momenta.
Middle-aged heterozygous carriers of Wilson's disease do not ...
Indian Academy of Sciences (India)
957 Warsaw, Poland. 2Medical University of Warsaw, Department of Experimental and Clinical Pharmacology, 00–325 Warsaw, Poland. Introduction. Wilson disease (WD) is an autosomal recessive disor- der of copper (Cu) metabolism (OMIM ...
Energy Technology Data Exchange (ETDEWEB)
Ablinger, J.; Hasselhuhn, A.; Schneider, C. [Johannes Kepler Univ., Linz (Austria). Research Inst. for Symbolic Computation (RISC); Behring, A.; Bluemlein, J.; Freitas, A. de; Raab, C.; Round, M. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Manteuffel, A. von [Mainz Univ. (Germany). PRISMA Cluster of Excellence; Wissbrock, F. [Johannes Kepler Univ., Linz (Austria). Research Inst. for Symbolic Computation (RISC); Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); IHES Institut des Hautes Etudes Scientifiques, Bures-sur-Yvette (France)
2014-07-15
We report on our latest results in the calculation of the three-loop heavy flavor contributions to the Wilson coefficients in deep-inelastic scattering in the asymptotic region Q{sup 2}>>m{sup 2}. We discuss the different methods used to compute the required operator matrix elements and the corresponding Feynman integrals. These methods very recently allowed us to obtain a series of new operator matrix elements and Wilson coefficients like the flavor non-singlet and pure singlet Wilson coefficients.
The value-adding CFO: an interview with Disney's Gary Wilson. Interview by Geraldine E. Willigan.
Wilson, G
1990-01-01
Financing a company is more complex than ever-and more important to its economic success. The demands on a CFO are tremendous. Optimizing capital costs requires an unprecedented level of technical sophistication. Yet the best CFOs today are not mere technicians. They are also strategists and innovators. Gary Wilson exemplifies the new CFO. In his 5 years as executive vice president and CFO of the Walt Disney Company and his 12 years at Marriott Corporation, he has shown how the finance function can add value-not just account for it. How does a CFO create value for shareholders? "Just like all the great marketing and operating executives," Wilson says, "by being creative." To Wilson, being creative means rethinking assumptions and finding clever ways to achieve financial and strategic goals. Some of Wilson's innovative deal making-like the off-balance-sheet financing he used at Marriott-is well known. At Marriott, he discovered the power of separating the ownership of an asset from its control. Marriott's strength was in operations, yet the company had a great deal of money tied up in real estate. Growth would require even more investment in real estate. Wilson's solution was to sell the hotels-in effect, removing them and the debt used to finance them from the balance sheet-and contract to operate them. In this interview, Wilson gives his view of the role of finance in today's corporation and explains the thinking behind some of the successful deals he has engineered-including Disney's Silver Screen movie-making partnerships and Euro Disneyland.
Energy-momentum tensor correlation function in Nf = 2 + 1 full QCD at finite temperature
Directory of Open Access Journals (Sweden)
Taniguchi Yusuke
2018-01-01
Full Text Available We measure correlation functions of the nonperturbatively renormalized energy-momentum tensor in Nf = 2 + 1 full QCD at finite temperature by applying the gradient flow method both to the gauge and quark fields. Our main interest is to study the conservation law of the energy-momentum tensor and to test whether the linear response relation is properly realized for the entropy density. By using the linear response relation we calculate the specific heat from the correlation function. We adopt the nonperturba-tively improved Wilson fermion and Iwasaki gauge action at a fine lattice spacing = 0:07 fm. In this paper the temperature is limited to a single value T ≃ 232 MeV. The u, d quark mass is rather heavy with mπ=mρ ≃ 0:63 while the s quark mass is set to approximately its physical value.
Search for Activity in Comet-Asteroid Transition Object 107P/Wilson-Harrington
Khayat, Alain; Meech, K.; Pittichova, J.; Schorghofer, N.; Yang, B.; Sonnett, S.; Riesen, T.; Kleyna, J.; Kaluna, H.; Keane, J.
2010-10-01
Comet-asteroid transition object 107P/Wilson-Harrington was observed near its October 22, 2009 perihelion passage to search for activity. No activity was detected. Consequently, we place limits on possible dust production of 0.013 kg/s at 1.23 AU. Furthermore, the data was not sufficient to constrain a rotation period; however, it is clear that the rotation period is > 4hr. Our data is consistent with the observations of others (6.1 hr). Phase function fitting yielded a value of the phase coefficient beta= 0.0406 ± .0001 mag/deg, similar to C-type asteroids that have a linear phase curve at large phase angles. Thermal models for 107P/Wilson-Harrington show that the average loss rate of exposed crystalline ice at zero latitude is in the order of 0.3 meters/year. The derived high loss rate suggests that 107P/Wilson-Harrington is deprived of surface ice. Our observations and analysis confirm earlier findings that 107P/Wilson-Harrington is an example of the very few such objects discovered so far. Such study we made is a critical next step in understanding the life of dormant comets, and a window into the evolutionary end states of the lives of comets that become extinct. This work has been supported in part by AST-0807521 from the National Science Foundation.
Non-perturbative renormalization of three-quark operators
Energy Technology Data Exchange (ETDEWEB)
Goeckeler, Meinulf [Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Horsley, Roger [Edinburgh Univ. (United Kingdom). School of Physics and Astronomy; Kaltenbrunner, Thomas [Regensburg Univ. (DE). Inst. fuer Theoretische Physik] (and others)
2008-10-15
High luminosity accelerators have greatly increased the interest in semi-exclusive and exclusive reactions involving nucleons. The relevant theoretical information is contained in the nucleon wavefunction and can be parametrized by moments of the nucleon distribution amplitudes, which in turn are linked to matrix elements of local three-quark operators. These can be calculated from first principles in lattice QCD. Defining an RI-MOM renormalization scheme, we renormalize three-quark operators corresponding to low moments non-perturbatively and take special care of the operator mixing. After performing a scheme matching and a conversion of the renormalization scale we quote our final results in the MS scheme at {mu}=2 GeV. (orig.)
Wilson loops in very high order lattice perturbation theory
International Nuclear Information System (INIS)
Ilgenfritz, E.M.; Nakamura, Y.; Perlt, H.; Schiller, A.; Rakow, P.E.L.; Schierholz, G.; Regensburg Univ.
2009-10-01
We calculate Wilson loops of various sizes up to loop order n=20 for lattice sizes of L 4 (L=4,6,8,12) using the technique of Numerical Stochastic Perturbation Theory in quenched QCD. This allows to investigate the behaviour of the perturbative series at high orders. We discuss three models to estimate the perturbative series: a renormalon inspired fit, a heuristic fit based on an assumed power-law singularity and boosted perturbation theory. We have found differences in the behavior of the perturbative series for smaller and larger Wilson loops at moderate n. A factorial growth of the coefficients could not be confirmed up to n=20. From Monte Carlo measured plaquette data and our perturbative result we estimate a value of the gluon condensate left angle (α)/(π)GG right angle. (orig.)
Lee, Hae Won; Kang, Jin Du; Yeo, Chang Woo; Yoon, Sung Woon; Lee, Kwang Jae; Choi, Mun Ki
2016-08-01
Wilson's disease typically presents symptoms associated with liver damage or neuropsychiatric disturbances, while endocrinologic abnormalities are rare. We report an unprecedented case of hypopituitarism in a patient with Wilson's disease. A 40-year-old woman presented with depression, general weakness and anorexia. Laboratory tests and imaging studies were compatible with liver cirrhosis due to Wilson's disease. Basal hormone levels and pituitary function tests indicated secondary hypothyroidism and adrenal insufficiency due to hypopituitarism. Brain MRI showed T2 hyperintense signals in both basal ganglia and midbrain but the pituitary imaging was normal. She is currently receiving chelation therapy along with thyroid hormone and steroid replacement. There may be a relationship between Wilson's disease and hypopituitarism. Copper deposition or secondary neuronal damage in the pituitary may be a possible explanation for this theory.
The strong coupling from a nonperturbative determination of the Λ parameter in three-flavor QCD
Energy Technology Data Exchange (ETDEWEB)
Bruno, Mattia [Brookhaven National Laboratory, Upton, NY (United States). Physics Dept.; Dalla Brida, Mattia [Univ. di Milano-Bicocca (Italy). Dipt. di Fisica; INFN, Sezione di Milano-Bicocca (Italy); Fritzsch, Patrick; Ramos, Alberto [CERN, Geneva (Switzerland). Theoretical Physics Dept.; Korzec, Tomasz [Wuppertal Univ. (Germany). Dept. of Physics; Schaefer, Stefan; Simma, Hubert [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Sint, Stefan [Trinity College Dublin (Ireland). School of Mathematics and Hamilton Mathematics Inst.; Sommer, Rainer [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Collaboration: ALPHA Collaboration
2017-07-15
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 GeV to 70 GeV, and using experimental input values for the masses and decay constants of the pion and the kaon, we obtain Λ{sup (3)}{sub MS}=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{sup (5)}{sub MS}/Λ{sup (3)}{sub MS} yields α{sup (5)}{sub MS}(m{sub Z})=0.11852(84).
Lattice field theories: non-perturbative methods of analysis
International Nuclear Information System (INIS)
Weinstein, M.
1978-01-01
A lecture is given on the possible extraction of interesting physical information from quantum field theories by studying their semiclassical versions. From the beginning the problem of solving for the spectrum states of any given continuum quantum field theory is considered as a giant Schroedinger problem, and then some nonperturbative methods for diagonalizing the Hamiltonian of the theory are explained without recourse to semiclassical approximations. The notion of a lattice appears as an artifice to handle the problems associated with the familiar infrared and ultraviolet divergences of continuum quantum field theory and in fact for all but gauge theories. 18 references
Uncovering the triple omeron vertex from Wilson line formalism
International Nuclear Information System (INIS)
Chirilli, G. A.; Szymanowski, L.; Wallon, S.
2011-01-01
We compute the triple omeron vertex from the Wilson line formalism, including both planar and nonplanar contributions, and get perfect agreement with the result obtained in the Extended Generalized Logarithmic Approximation based on Reggeon calculus.
"Mens Sana in Corpore Sano": Human Values in Thomas Wilson's "The Arte of Rhetorique."
Luehring, Janet
In 1553 the work that is touted as the first complete book written in English on rhetoric was published, Thomas Wilson's "Arte of Rhetorique." It became so popular it enjoyed eight printings within its century. Wilson was not a person to translate and read just for knowledge; he believed that knowledge should be imparted to the general…
Non-perturbative aspects of quantum field theory. From the quark-gluon plasma to quantum gravity
International Nuclear Information System (INIS)
Christiansen, Nicolai
2015-01-01
In this dissertation we investigate several aspects of non-perturbative quantum field theory. Two main parts of the thesis are concerned with non-perturbative renormalization of quantum gravity within the asymptotic safety scenario. This framework is based on a non-Gaussian ultraviolet fixed point and provides a well-defined theory of quantized gravity. We employ functional renormalization group (FRG) techniques that allow for the study of quantum fields even in strongly coupled regimes. We construct a setup for the computation of graviton correlation functions and analyze the ultraviolet completion of quantum gravity in terms of the properties of the two- and three point function of the graviton. Moreover, the coupling of gravity to Yang-Mills theories is discussed. In particular, we study the effects of graviton induced interactions on asymptotic freedom on the one hand, and the role of gluonic fluctuations in the gravity sector on the other hand. The last subject of this thesis is the physics of the quark-gluon plasma. We set-up a general non-perturbative strategy for the computation of transport coefficients in non-Abelian gauge theories. We determine the viscosity over entropy ratio η/s in SU(3) Yang-Mills theory as a function of temperature and estimate its behavior in full quantum chromodynamics (QCD).
On strong-coupling correlation functions of circular Wilson loops and local operators
International Nuclear Information System (INIS)
Alday, Luis F; Tseytlin, Arkady A
2011-01-01
Motivated by the problem of understanding 3-point correlation functions of gauge-invariant operators in N=4 super Yang-Mills theory we consider correlators involving Wilson loops and a 'light' operator with fixed quantum numbers. At leading order in the strong-coupling expansion such correlators are given by the 'light' vertex operator evaluated on a semiclassical string world surface ending on the corresponding loops at the boundary of AdS 5 x S 5 . We study in detail the example of a correlator of two concentric circular Wilson loops and a dilaton vertex operator. The resulting expression is given by an integral of combinations of elliptic functions and can be computed analytically in some special limits. We also consider a generalization of the minimal surface ending on two circles to the case of non-zero angular momentum J in S 5 and discuss a special limit when one of the Wilson loops is effectively replaced by a 'heavy' operator with charge J. (paper)
Resurgent Transseries and the Holomorphic Anomaly: Nonperturbative Closed Strings in Local CP2
Couso-Santamaría, Ricardo; Schiappa, Ricardo; Vonk, Marcel
2015-01-01
The holomorphic anomaly equations describe B-model closed topological strings in Calabi-Yau geometries. Having been used to construct perturbative expansions, it was recently shown that they can also be extended past perturbation theory by making use of resurgent transseries. These yield formal nonperturbative solutions, showing integrability of the holomorphic anomaly equations at the nonperturbative level. This paper takes such constructions one step further by working out in great detail the specific example of topological strings in the mirror of the local CP2 toric Calabi-Yau background, and by addressing the associated (resurgent) large-order analysis of both perturbative and multi-instanton sectors. In particular, analyzing the asymptotic growth of the perturbative free energies, one finds contributions from three different instanton actions related by Z_3 symmetry, alongside another action related to the Kahler parameter. Resurgent transseries methods then compute, from the extended holomorphic anomal...
Nonperturbative quantum electrodynamics in a photon-condensate background field
International Nuclear Information System (INIS)
Kikuchi, Y.; Ng, Y.J.
1988-01-01
Analyses of the Schwinger-Dyson (SD) equation for the fermion self-energy have revealed the existence of a QED ultraviolet nonperturbative fixed point which separates a strong-coupling regime from a weak-coupling regime. Here we study the SD equation in the presence of a weak constant photon-condensate background field. This background field does not seem to affect the fixed point. Better approximations or some more realistic background fields may change the result. The investigation is partly motivated by recent heavy-ion experiments
International Nuclear Information System (INIS)
Fletcher, S.K.
2002-01-01
1 - Description of program or function: The three programs SPLPKG, WFCMPR, and WFAPPX provide the capability for interactively generating, comparing and approximating Wilson-Fowler Splines. The Wilson-Fowler spline is widely used in Computer Aided Design and Manufacturing (CAD/CAM) systems. It is favored for many applications because it produces a smooth, low curvature fit to planar data points. Program SPLPKG generates a Wilson-Fowler spline passing through given nodes (with given end conditions) and also generates a piecewise linear approximation to that spline within a user-defined tolerance. The program may be used to generate a 'desired' spline against which to compare other Splines generated by CAD/CAM systems. It may also be used to generate an acceptable approximation to a desired spline in the event that an acceptable spline cannot be generated by the receiving CAD/CAM system. SPLPKG writes an IGES file of points evaluated on the spline and/or a file containing the spline description. Program WFCMPR computes the maximum difference between two Wilson-Fowler Splines and may be used to verify the spline recomputed by a receiving system. It compares two Wilson-Fowler Splines with common nodes and reports the maximum distance between curves (measured perpendicular to segments) and the maximum difference of their tangents (or normals), both computed along the entire length of the Splines. Program WFAPPX computes the maximum difference between a Wilson- Fowler spline and a piecewise linear curve. It may be used to accept or reject a proposed approximation to a desired Wilson-Fowler spline, even if the origin of the approximation is unknown. The maximum deviation between these two curves, and the parameter value on the spline where it occurs are reported. 2 - Restrictions on the complexity of the problem - Maxima of: 1600 evaluation points (SPLPKG), 1000 evaluation points (WFAPPX), 1000 linear curve breakpoints (WFAPPX), 100 spline Nodes
Wilson loops en la correspondencia AdS/CFT
Aguilera Damia, Jeremías
2017-01-01
Esta tesis está abocada al estudio de operadores no locales e invariantes de gauge, denominados Wilson loops, tanto a través de técnicas propias de teoría de cuerdas como por medio de técnicas avanzadas en teorías de gauge.
Wilson and Gisvold's textbook of organic medicinal and pharmaceutical chemistry
National Research Council Canada - National Science Library
Wilson, Charles Owens; Beale, John Marlowe; Block, John H
2011-01-01
"For over half a century, Wilson and Gisvold's Textbook of Organic Medicinal and Pharmaceutical Chemistry has served the discipline of medicinal chemistry for both graduate and undergraduate pharmacy...
Zhang, Yu-Yu; Chen, Xiang-You
2017-12-01
An unexplored nonperturbative deep strong coupling (npDSC) achieved in superconducting circuits has been studied in the anisotropic Rabi model by the generalized squeezing rotating-wave approximation. Energy levels are evaluated analytically from the reformulated Hamiltonian and agree well with numerical ones in a wide range of coupling strength. Such improvement ascribes to deformation effects in the displaced-squeezed state presented by the squeezed momentum variance, which are omitted in previous displaced states. The atom population dynamics confirms the validity of our approach for the npDSC strength. Our approach offers the possibility to explore interesting phenomena analytically in the npDSC regime in qubit-oscillator experiments.
Transformation of a Free-Wilson matrix into Fourier coefficients
Czech Academy of Sciences Publication Activity Database
Holík, M.; Halámek, Josef
2002-01-01
Roč. 20, - (2002), s. 422 - 428 ISSN 0931-8771 Institutional research plan: CEZ:AV0Z2065902 Keywords : Free-Wilson matrix * Fourier transform * multivariate regression Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.558, year: 2002
Lifebox | Wilson | Southern African Journal of Anaesthesia and ...
African Journals Online (AJOL)
Southern African Journal of Anaesthesia and Analgesia. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 18, No 1 (2012) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register. Lifebox. IH Wilson. Abstract.
Perturbation calculations with Wilson loop
International Nuclear Information System (INIS)
Peixoto Junior, L.B.
1984-01-01
We present perturbative calculations with the Wilson loop (WL). The dimensional regularization method is used with a special attention concerning to the problem of divergences in the WL expansion in second and fourth orders, in three and four dimensions. We show that the residue in the pole, in 4d, of the fourth order graphs contribution sum is important for the charge renormalization. We compute up to second order the exact expression of the WL, in three-dimensional gauge theories with topological mass as well as its assimptotic behaviour for small and large distances. the author [pt
Wilson's Disease: Expect the Unexpected.
El Imad, Talal; Al Moussawi, Hassan; Haddad, Fady G; Felix, Richard; Mulrooney, Stephen M
2018-02-08
A 64-year-old woman, presented with abdominal distention, jaundice and resting tremor, was found to have liver injury and abnormal liver enzymes. A computed tomography (CT) scan of the abdomen and pelvis showed abdominopelvic ascites and signs of liver cirrhosis. An extensive liver disease workup was performed and came back negative; therefore, a liver biopsy was obtained and showed evidence of cirrhosis with elevated liver copper consistent with Wilson's disease (WD). We report a unique case of late-onset WD in which the ceruloplasmin level and 24-h urinary copper excretion were all normal.
Probing non-perturbative effects in M-theory
International Nuclear Information System (INIS)
Hatsuda, Yasuyuki; Okuyama, Kazumi
2014-07-01
The AdS/CFT correspondence enables us to probe M-theory on various backgrounds from the corresponding dual gauge theories. Here we investigate in detail a three-dimensional U(N) N=4 super Yang-Mills theory coupled to one adjoint hypermultiplet and N f fundamental hypermultiplets, which is large N dual to M-theory on AdS 4 x S 7 /Z N f . Using the localization and the Fermi-gas formulation, we explore non-perturbative corrections to the partition function. As in the ABJM theory, we find that there exists a non-trivial pole cancellation mechanism, which guarantees the theory to be well-defined, between worldsheet instantons and membrane instantons for all rational (in particular, physical or integral) values of N f .
Non-perturbative field theory/field theory on a lattice
International Nuclear Information System (INIS)
Ambjorn, J.
1988-01-01
The connection between the theory of critical phenomena in statistical mechanics and the renormalization of field theory is briefly outlined. The way of using this connection is described to get information about non-perturbative quantities in QCD and about more intelligent ways of doing the Monte Carlo (MC) simulations. The (MC) method is shown to be a viable one in high energy physics, but it is not a good substitute for an analytic understanding. MC-methods will be very valuable both for getting out hard numbers and for testing the correctness of new ideas
Nonperturbative quantum geometries
International Nuclear Information System (INIS)
Jacobson, T.; California Univ., Santa Barbara; Smolin, L.; California Univ., Santa Barbara
1988-01-01
Using the self-dual representation of quantum general relativity, based on Ashtekar's new phase space variables, we present an infinite dimensional family of quantum states of the gravitational field which are exactly annihilated by the hamiltonian constraint. These states are constructed from Wilson loops for Ashtekar's connection (which is the spatial part of the left handed spin connection). We propose a new regularization procedure which allows us to evaluate the action of the hamiltonian constraint on these states. Infinite linear combinations of these states which are formally annihilated by the diffeomorphism constraints as well are also described. These are explicit examples of physical states of the gravitational field - and for the compact case are exact zero eigenstates of the hamiltonian of quantum general relativity. Several different approaches to constructing diffeomorphism invariant states in the self dual representation are also described. The physical interpretation of the states described here is discussed. However, as we do not yet know the physical inner product, any interpretation is at this stage speculative. Nevertheless, this work suggests that quantum geometry at Planck scales might be much simpler when explored in terms of the parallel transport of left-handed spinors than when explored in terms of the three metric. (orig.)
Electromagnetic corrections to the hadronic vacuum polarization of the photon within QEDL and QEDM
Bussone, Andrea; Della Morte, Michele; Janowski, Tadeusz
2018-03-01
We compute the leading QED corrections to the hadronic vacuum polarization (HVP) of the photon, relevant for the determination of leptonic anomalous magnetic moments, al. We work in the electroquenched approximation and use dynamical QCD configurations generated by the CLS initiative with two degenerate flavors of nonperturbatively O(a)-improved Wilson fermions. We consider QEDL and QEDM to deal with the finite-volume zero modes. We compare results for the Wilson loops with exact analytical determinations. In addition we make sure that the volumes and photon masses used in QEDM are such that the correct dispersion relation is reproduced by the energy levels extracted from the charged pions two-point functions. Finally we compare results for pion masses and the HVP between QEDL and QEDM. For the vacuum polarization, corrections with respect to the pure QCD case, at fixed pion masses, turn out to be at the percent level.
Nonperturbative effects in B → Xsl+l- for large dilepton invariant mass
International Nuclear Information System (INIS)
Buchalla, G.
1998-01-01
The authors consider the calculation of O(Λ QCD 2 /m b 2 ) nonperturbative corrections to B → X s l + l - decay. The analysis confirms the results of Ali et al. for the dilepton invariant mass spectrum, which were in disagreement with an earlier publication, and for the lepton forward-backward asymmetry. The authors also give expressions for the O(Λ QCD 2 /m b 2 ) corrections to the left-right asymmetry. In addition the authors discuss the breakdown of the heavy quark expansion near the point of maximal dilepton invariant mass q 2 and consider a model independent approach to this region using heavy hadron chiral perturbation theory. The modes B → Kl + l - and B → Kπl + l - , which determine the endpoint region of the inclusive decay, are analysed within this framework. An interpolation is suggested between the region of moderately high q 2 , where the heavy quark expansion is still valid, and the vicinity of the endpoint described by chiral perturbation theory. The authors also comment on further nonperturbative effects in B → Kl + l -
Revisiting the dilatation operator of the Wilson-Fisher fixed point
Energy Technology Data Exchange (ETDEWEB)
Liendo, Pedro [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Theory Group
2017-01-15
We revisit the order ε dilatation operator of the Wilson-Fisher fixed point obtained by Kehrein, Pismak, and Wegner in light of recent results in conformal field theory. Our approach is algebraic and based only on symmetry principles. The starting point of our analysis is that the first correction to the dilatation operator is a conformal invariant, which implies that its form is fixed up to an infinite set of coefficients associated with the scaling dimensions of higher-spin currents. These coefficients can be fixed using well-known perturbative results, however, they were recently re-obtained using CFT arguments without relying on perturbation theory. Our analysis then implies that all order-ε scaling dimensions of the Wilson-Fisher fixed point can be fixed by symmetry.
Menger, Richard P; Storey, Christopher M; Guthikonda, Bharat; Missios, Symeon; Nanda, Anil; Cooper, John M
2015-07-01
World War I catapulted the United States from traditional isolationism to international involvement in a major European conflict. Woodrow Wilson envisaged a permanent American imprint on democracy in world affairs through participation in the League of Nations. Amid these defining events, Wilson suffered a major ischemic stroke on October 2, 1919, which left him incapacitated. What was probably his fourth and most devastating stroke was diagnosed and treated by his friend and personal physician, Admiral Cary Grayson. Grayson, who had tremendous personal and professional loyalty to Wilson, kept the severity of the stroke hidden from Congress, the American people, and even the president himself. During a cabinet briefing, Grayson formally refused to sign a document of disability and was reluctant to address the subject of presidential succession. Wilson was essentially incapacitated and hemiplegic, yet he remained an active president and all messages were relayed directly through his wife, Edith. Patient-physician confidentiality superseded national security amid the backdrop of friendship and political power on the eve of a pivotal juncture in the history of American foreign policy. It was in part because of the absence of Woodrow Wilson's vocal and unwavering support that the United States did not join the League of Nations and distanced itself from the international stage. The League of Nations would later prove powerless without American support and was unable to thwart the rise and advance of Adolf Hitler. Only after World War II did the United States assume its global leadership role and realize Wilson's visionary, yet contentious, groundwork for a Pax Americana. The authors describe Woodrow Wilson's stroke, the historical implications of his health decline, and its impact on United States foreign policy.
Non-perturbative construction of the Luttinger-Ward functional
Directory of Open Access Journals (Sweden)
M.Potthoff
2006-01-01
Full Text Available For a system of correlated electrons, the Luttinger-Ward functional provides a link between static thermodynamic quantities on the one hand and single-particle excitations on the other. The functional is useful in deriving several general properties of the system as well as in formulating the thermodynamically consistent approximations. Its original construction, however, is perturbative as it is based on the weak-coupling skeleton-diagram expansion. Here, it is shown that the Luttinger-Ward functional can be derived within a general functional-integral approach. This alternative and non-perturbative approach stresses the fact that the Luttinger-Ward functional is universal for a large class of models.
World-Line Formalism: Non-Perturbative Applications
Directory of Open Access Journals (Sweden)
Dmitry Antonov
2016-11-01
Full Text Available This review addresses the impact on various physical observables which is produced by confinement of virtual quarks and gluons at the level of the one-loop QCD diagrams. These observables include the quark condensate for various heavy flavors, the Yang-Mills running coupling with an infra-red stable fixed point, and the correlation lengths of the stochastic Yang-Mills fields. Other non-perturbative applications of the world-line formalism presented in the review are devoted to the determination of the electroweak phase-transition critical temperature, to the derivation of a semi-classical analogue of the relation between the chiral and the gluon QCD condensates, and to the calculation of the free energy of the gluon plasma in the high-temperature limit. As a complementary result, we demonstrate Casimir scaling of k-string tensions in the Gaussian ensemble of the stochastic Yang-Mills fields.
Non-perturbative description of quantum systems
Feranchuk, Ilya; Le, Van-Hoang; Ulyanenkov, Alexander
2015-01-01
This book introduces systematically the operator method for the solution of the Schrödinger equation. This method permits to describe the states of quantum systems in the entire range of parameters of Hamiltonian with a predefined accuracy. The operator method is unique compared with other non-perturbative methods due to its ability to deliver in zeroth approximation the uniformly suitable estimate for both ground and excited states of quantum system. The method has been generalized for the application to quantum statistics and quantum field theory. In this book, the numerous applications of operator method for various physical systems are demonstrated. Simple models are used to illustrate the basic principles of the method which are further used for the solution of complex problems of quantum theory for many-particle systems. The results obtained are supplemented by numerical calculations, presented as tables and figures.
Srpangers, M.; van den Brink, W.P.; van Heerden, J.; Hoogstraten, J.
1987-01-01
Critiques P. White's analysis of R. Nisbett and T. Wilson's work on the limitations to conscious awareness of mental processes. A reanalysis of White's data demonstrated no evidence for his hypothesis that report accuracy is improved by memory for the events of the relevant process. In addition,
Charm quark mass and D-meson decay constants from two-flavour lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Heitger, Jochen [Muenster Univ. (Germany). Inst. fuer Theoretische Physik 1; Hippel, Georg M. von [Mainz Univ. (Germany). Inst. fuer Kernphysik; Schaefer, Stefan; Virotta, Francesco [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC
2013-12-15
We present a computation of the charm quark's mass and the leptonic D-meson decay constants f{sub D} and f{sub D{sub s}} in two-flavour lattice QCD with non-perturbatively O(a) improvedWilson quarks. Our analysis is based on the CLS configurations at two lattice spacings (a=0.065 and 0.048 fm, where the lattice scale is set by f{sub K}) and pion masses ranging down to {proportional_to}190 MeV at Lm{sub {pi}}>or similar 4, in order to perform controlled continuum and chiral extrapolations with small systematic uncertainties.
The pion form factor from lattice QCD with two dynamical flavours
Energy Technology Data Exchange (ETDEWEB)
Broemmel, D. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Gruppe Theorie]|[Regensburg Univ. (Germany). Inst. fuer Physik 1 - Theoretische Physik; Diehl, M. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Gruppe Theorie; Goeckeler, M. [Regensburg Univ. (DE). Inst. fuer Physik 1 - Theoretische Physik] (and others)
2006-08-15
We compute the electromagnetic form factor of the pion using non-perturbatively O(a) improved Wilson fermions. The calculations are done for pion masses down to 400 MeV and for lattice spacings of 0.07-0.11 fm. We check for finite size effects by repeating some of the measurements on smaller lattices. The large number of lattice parameters we use allows us to extrapolate to the physical point. For the square of the charge radius we find left angle r{sup 2} right angle =0.440(19) fm{sup 2}, in good agreement with experiment. (orig.)
Pauli-Villars regularization in nonperturbative Hamiltonian approach on the light front
Energy Technology Data Exchange (ETDEWEB)
Malyshev, M. Yu., E-mail: mimalysh@yandex.ru; Paston, S. A.; Prokhvatilov, E. V.; Zubov, R. A.; Franke, V. A. [Saint Petersburg State University, Saint Petersburg (Russian Federation)
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.
Nonperturbative approach to quantum field theories: phase transitions and confinement
International Nuclear Information System (INIS)
Yankielowicz, S.
1976-08-01
Lectures are given on a nonperturbative approach to quantum field theories. Phenomena are discussed for which the usual weak coupling perturbative approach in terms of Feynman diagrams is of no assistance. Properties associated with large distance behavior, i.e., phase transitions, low lying spectra, coherent excitations which are presumably built out of the long wave structure of the theory are described. These methods are important for the study of strong coupling field theories and the question of quarks confinement. 25 references
2010-10-01
... rails, woodcock, and common (Wilson's) snipe. 20.104 Section 20.104 Wildlife and Fisheries UNITED STATES... for rails, woodcock, and common (Wilson's) snipe. This section provides for the annual hunting of certain rails, woodcock, and snipe in the 48 contiguous United States. [44 FR 7148, Feb. 6, 1979...
AN EXPERIMENTAL ASSESSMENT OF THE PLATE HEAT EXCHANGER CHARACTERISTICS BY WILSON PLOT METHOD
Directory of Open Access Journals (Sweden)
Jan Opatřil
2016-10-01
Full Text Available An aim of this paper is suggestion of the evaluation method based on the experimental data and the Wilson plot method for the Plate Heat Exchangers (PHE. For the purpose of the project the new experimental loop was built for the testing of PHE to obtain the overhaul heat transfer coefficient and pressure drop between inlet and outlet of the fluid. The measurement were done for three different PHE with the performance range 30-100kW. The working fluid was water on both sides of the PHE. The differences are in number of pates as well as in extrusion profiles. The Wilson plot evaluation method was involved for the processing experimental data. To obtain more accurate correlations between the experimental data and theoretical results yield of the Wilson plot, the method was enhanced by the measured pressure drop involving. This approach could be useful for PHE designing software and for the manufacturing company.
Probing Wilson loops in N=4 Chern–Simons-matter theories at weak coupling
Directory of Open Access Journals (Sweden)
Luca Griguolo
2016-02-01
Full Text Available For three-dimensional N=4 super-Chern–Simons-matter theories associated to necklace quivers U(N0×U(N1×⋯U(N2r−1, we study at quantum level the two kinds of 1/2 BPS Wilson loop operators recently introduced in arXiv:1506.07614. We perform a two-loop evaluation and find the same result for the two kinds of operators, so moving to higher loops a possible quantum uplift of the classical degeneracy. We also compute the 1/4 BPS bosonic Wilson loop and discuss the quantum version of the cohomological equivalence between fermionic and bosonic Wilson loops. We compare the perturbative result with the Matrix Model prediction and find perfect matching, after identification and remotion of a suitable framing factor. Finally, we discuss the potential appearance of three-loop contributions that might break the classical degeneracy and briefly analyze possible implications on the BPS nature of these operators.
Parton densities in quantum chromodynamics. Gauge invariance, path-dependence, and Wilson lines
International Nuclear Information System (INIS)
Cherednikov, Igor O.
2017-01-01
The purpose of this book is to give a systematic pedagogical exposition of the quantitative analysis of Wilson lines and gauge-invariant correlation functions in quantum chromodynamics. Using techniques from the previous volume (Wilson Lines in Quantum Field Theory, 2014), an ab initio methodology is developed and practical tools for its implementation are presented. Emphasis is put on the implications of gauge invariance and path-dependence properties of transverse-momentum dependent parton density functions. The latter are associated with the QCD factorization approach to semi-inclusive hadronic processes, studied at currently operating and planned experimental facilities.
Parton densities in quantum chromodynamics. Gauge invariance, path-dependence, and Wilson lines
Energy Technology Data Exchange (ETDEWEB)
Cherednikov, Igor O. [Antwerpen Univ. (Belgium). Dept. Fysica; Veken, Frederik F. van der [CERN, Geneva (Switzerland)
2017-05-01
The purpose of this book is to give a systematic pedagogical exposition of the quantitative analysis of Wilson lines and gauge-invariant correlation functions in quantum chromodynamics. Using techniques from the previous volume (Wilson Lines in Quantum Field Theory, 2014), an ab initio methodology is developed and practical tools for its implementation are presented. Emphasis is put on the implications of gauge invariance and path-dependence properties of transverse-momentum dependent parton density functions. The latter are associated with the QCD factorization approach to semi-inclusive hadronic processes, studied at currently operating and planned experimental facilities.
New WZW D-branes from the algebra of Wilson loop operators
International Nuclear Information System (INIS)
Monnier, Samuel
2009-01-01
We investigate the algebra generated by the topological Wilson loop operators in WZW models. Wilson loops describe the nontrivial fixed points of the boundary renormalization group flows triggered by Kondo perturbations. Their enveloping algebra therefore encodes all the fixed points which can be reached by sequences of Kondo flows. This algebra is easily described in the case of SU(2), but displays a very rich structure for higher rank groups. In the latter case, its action on known D-branes creates a profusion of new and generically non-rational D-branes. We describe their symmetries and the geometry of their worldvolumes. We briefly explain how to extend these results to coset models.
Metabolism of 25-hydroxyvitamin D in copper-laden rat: A model of Wilson's disease
International Nuclear Information System (INIS)
Carpenter, T.O.; Pendrak, M.L.; Anast, C.S.
1988-01-01
Wilson's disease results in excess tissue accumulation of copper and is often complicated by skeletal and mineral abnormalities. The authors investigated vitamin D metabolism in rats fed a copper-laden diet rendering hepatic copper content comparable with that found in Wilson's disease. Injection of 25-hydroxyvitamin D 3 [25(OH)D 3 ] resulted in reduced 1,25--dihydroxyvitamin D [1,25(OH) 2 D] levels in copper-intoxicated rats. In vitro 25(OH)D-1α-hydroxylase activity was impaired in renal mitochondria from copper-intoxicated animals. Activity was also inhibited in mitochondrial from controls when copper was added to incubation media. Impaired conversion of 25(OH)D to 1,25(OH) 2 D occurs in copper intoxication and suggests that altered vitamin D metabolism is a potential factor in the development of bone and mineral abnormalities in Wilson's disease
Toward precision holography with supersymmetric Wilson loops
Energy Technology Data Exchange (ETDEWEB)
Faraggi, Alberto [Instituto de Física, Pontificia Universidad Católica de Chile,Casilla 306, Santiago (Chile); Zayas, Leopoldo A. Pando [The Abdus Salam International Centre for Theoretical Physics,Strada Costiera 11, 34014 Trieste (Italy); Michigan Center for Theoretical Physics, Department of Physics,University of Michigan, Ann Arbor, MI 48109 (United States); Silva, Guillermo A. [Instituto de Física de La Plata - CONICET & Departamento de Física - UNLP,C.C. 67, 1900 La Plata (Argentina); Trancanelli, Diego [Institute of Physics, University of São Paulo,05314-970 São Paulo (Brazil)
2016-04-11
We consider certain 1/4 BPS Wilson loop operators in SU(N)N=4 supersymmetric Yang-Mills theory, whose expectation value can be computed exactly via supersymmetric localization. Holographically, these operators are mapped to fundamental strings in AdS{sub 5}×S{sup 5}. The string on-shell action reproduces the large N and large coupling limit of the gauge theory expectation value and, according to the AdS/CFT correspondence, there should also be a precise match between subleading corrections to these limits. We perform a test of such match at next-to-leading order in string theory, by deriving the spectrum of quantum fluctuations around the classical string solution and by computing the corresponding 1-loop effective action. We discuss in detail the supermultiplet structure of the fluctuations. To remove a possible source of ambiguity in the ghost zero mode measure, we compare the 1/4 BPS configuration with the 1/2 BPS one, dual to a circular Wilson loop. We find a discrepancy between the string theory result and the gauge theory prediction, confirming a previous result in the literature. We are able to track the modes from which this discrepancy originates, as well as the modes that by themselves would give the expected result.
Aggarwal, Annu; Bhatt, Mohit
2013-01-01
Wilson disease (WD) is an inherited disorder of chronic copper toxicosis characterized by excessive copper deposition in the body, primarily in the liver and the brain. It is a progressive disease and fatal if untreated. Excessive copper accumulation results from the inability of liver to excrete copper in bile. Copper is an essential trace metal and has a crucial role in many metabolic processes. Almost all of the body copper is protein bound. In WD, the slow but relentless copper accumulation overwhelms the copper chaperones (copper-binding proteins), resulting in high levels of free copper and copper-induced tissue injury. Liver is the central organ for copper metabolism, and copper is initially accumulated in the liver but over time spills to other tissues. WD has protean clinical manifestations mainly attributable to liver, brain, and osseomuscular impairment. Diagnosis of WD is challenging and based on combination of clinical features and laboratory tests. Identification of various high-frequency mutations identified in different population studies across the world has revived interest in developing DNA chips for rapid genetic diagnosis of WD. All symptomatic and all presymptomatic patients require lifelong decoppering with careful clinical tracking. Decoppering ensures that presymptomatic individuals remain symptom free. With judicious decoppering, given time, even patients with severe neurological disability improve and can return to normal life and resume school or work at par with their peers. Treatment regimens and tracking patients using the WD-specific Global Assessment Scale for WD (GAS for WD) are discussed. © 2013 Elsevier Inc. All rights reserved.
BOOK REVIEW: Democracy and Political Life in Nigeria | Wilson ...
African Journals Online (AJOL)
In this review of Victor Dike's book - \\"Democracy and Political Life in Nigeria\\", Inam Wilson underscores the author's attempts to draw a connection between Nigeria's chequered political history and her present economic trajectory to explain why Nigeria is today facing numerous sociopolitical and economic challenges, ...
Non-perturbative Aspects of QCD and Parameterized Quark Propagator
Institute of Scientific and Technical Information of China (English)
HAN Ding-An; ZHOU Li-Juan; ZENG Ya-Guang; GU Yun-Ting; CAO Hui; MA Wei-Xing; MENG Cheng-Ju; PAN Ji-Huan
2008-01-01
Based on the Global Color Symmetry Model, the non-perturbative QCD vacuum is investigated in theparameterized fully dressed quark propagator. Our theoretical predictions for various quantities characterized the QCD vacuum are in agreement with those predicted by many other phenomenological QCD inspired models. The successful predictions clearly indicate the extensive validity of our parameterized quark propagator used here. A detailed discussion on the arbitrariness in determining the integration cut-off parameter of# in calculating QCD vacuum condensates and a good method, which avoided the dependence of calculating results on the cut-off parameter is also strongly recommended to readers.
Wilson and Domainwall Kernels on Oakforest-PACS
Kanamori, Issaku; Matsufuru, Hideo
2018-03-01
We report the performance of Wilson and Domainwall Kernels on a new Intel Xeon Phi Knights Landing based machine named Oakforest-PACS, which is co-hosted by University of Tokyo and Tsukuba University and is currently fastest in Japan. This machine uses Intel Omni-Path for the internode network. We compare performance with several types of implementation including that makes use of the Grid library. The code is incorporated with the code set Bridge++.
Large x Behaviour and the Non-Perturbative Structure of Hadronic Systems
Energy Technology Data Exchange (ETDEWEB)
Anthony W. Thomas
2005-02-01
While the traditional interest in structure functions has been the confirmation of the predictions of perturbative QCD, this data also contains a wealth of information on how QCD works in the infrared, or confinement, region. As the challenge of the strong force now turns to the study of QCD in the non-perturbative region, such information is extremely valuable.We outline some of the key issues for both nucleon and nuclear structure functions.
Nonperturbative scale anomaly and composite operators in gauge field theories
International Nuclear Information System (INIS)
Gusynin, V.P.; Miranskij, V.A.
1987-01-01
In non-asymptotically free gauge theories with a non-trivial ultraviolet fixed point scale symmetry breaking (the scale anomaly) caused by the nonperturbative PCAC dynamics is studied. In the two-loop approximation the analytical expression for the gluon condensate is obtained. It is shown that the form of the anomaly depends on the type of the phase of a theory to which it relates. The hypothesis about the soft behaviour at small distances of composite operators in such theories is confirmed. 14 refs.; 1 fig
Comments on ''Geomagnetic response to magnetic clouds'' by Robert M. Wilson; and reply
International Nuclear Information System (INIS)
Gonzalez, W.D.; Gonzalez, A.L.C.; Wilson, R.M.
1988-01-01
The paper 'Geomagnetic Response to Magnetic Clouds' by Wilson (1987) tried to show an association between geomagnetic storm intervals and the passage of interplanetary magnetic clouds at the Earth's magnetosphere. The association is shown through a superposed epoch analysis of the interplanetary magnetic field (IMF)-B Z component and the D st geomagnetic storm index for 19 cloud events occurring between 1973 and 1978. Two aspects of the magnetic cloud-storm relationship are challenged. The first concerns the northward-southward rotation of the IMF-B Z component which is known to exist but not accounted for in Wilson's article. The second concerns the magnitude of the storms associated with the passage of magnetic clouds. In a reply Wilson explains the distinction between N-turning and S-turning clouds of the 19 clouds studied 12 were southward and 7 northward turning. The average behaviour of both is similar, the differences being due to the different onset values of D st . The second problem is attributed to a misunderstanding of the meaning of the I-bars given in the original article. The original results of Wilson are reaffirmed. The comment on the reply suggests that the average peak D st value for S-N clouds is larger by 30% than for the N-S clouds and that the final intensity of the storm can be altered by the type of cloud involved (S-N) or (N-S). (U.K.)
Values in Higher Education. The Wilson Lecture Series.
Wilson, O. Meredith
The text of a lecture in the University of Arizona Wilson Lecture Series on values in higher education is presented, with responses by Richard H. Gallagher, Jeanne McRae McCarthy, and Raymond H. Thompson. The theme of the talk is that man is by evolution and by necessity a thinking animal, who now finds himself in a technologically dependent…
Microstructure assessment of the thalamus in Wilson's disease using diffusion tensor imaging
International Nuclear Information System (INIS)
Li, G.; Zhou, X.; Xu, P.; Pan, X.; Chen, Y.
2014-01-01
Aim: To assess diffusion changes of the thalamus in Wilson's disease using diffusion tensor imaging (DTI). Materials and methods: Fifteen patients with Wilson's disease and an abnormal signal in the thalamus (designated as group 1) and 18 patients with Wilson's disease with a normal-appearing thalamus (designated as group 2) at conventional magnetic resonance imaging (MRI) were recruited. Fifteen age-matched and sex-matched healthy volunteers were also enrolled as the control group (designated as group 3). The fractional anisotropy (FA), primary eigenvalue (λ1), second eigenvalue (λ2), and third eigenvalue (λ3) of the thalamus were measured and the differences were compared. Results: The FA values of the thalamus were different in the three groups (group 1: 0.36 ± 0.02; group 2: 0.38 ± 0.02; group 3: 0.43 ± 0.02; F = 54.51, p 2 /s, 1.11 ± 0.06 mm 2 /s, and 1.10 ± 0.04 mm 2 /s of λ1 in group 1, group 2, and group 3, respectively; 0.82 ± 0.08 mm 2 /s, 0.78 ± 0.05 mm 2 /s, and 0.72 ± 0.02 mm 2 /s of λ2 in group 1, group 2, and group 3, respectively; 0.52 ± 0.05 mm 2 /s, 0.49 ± 0.06 mm 2 /s, and 0.42 ± 0.06 mm 2 /s of λ3 in group 1, group 2, and group 3, respectively; F = 1.65, p = 0.203 of λ1; F = 10.55, p < 0.001 of λ2; F = 4.21, p = 0.021 of λ3; respectively). A statistically significant difference in the λ2 value was observed between group 1 and group 3 (p < 0.001) and group 2 and group 3 (p = 0.005). A statistically significant difference in the λ3 value was also observed between group 1 and group 3 (p = 0.007). No significant difference in the λ1 value was noted between each of the two groups. Conclusions: Damage of the thalamus in Wilson's disease patients can be detected using DTI. DTI may provide information regarding thalamus damage in patients with Wilson's disease before abnormal signals on conventional MRI
Wilson's disease: start with psychiatric symptoms. Brain magnetic resonance findings
International Nuclear Information System (INIS)
Nagel, Jorge; Miralles, Sabrina
2007-01-01
Wilson's disease - hepatolenticular degeneration - is an autosomal recessive genetic disorder, characterized by an excessive and toxic accumulation of cooper in different tissues. This accumulation is produced by an inherited defect in cooper's biliary excretion. This rare disorder affects approximately one on 30.000 individuals. Signs and symptoms of hepatic, neurologic and psychiatric disease are the most common clinical presentations of symptomatic Wilson's disease. The diagnosis can usually be made by laboratory tests that find a decreased cooper binding protein in blood called ceruloplasmin, an increase in the excretion of cooper in 24 hour urine and the appearance of corneal Kayser-Fleischer ring. We present a 28 years patient who began with depression and panic attacks, followed by neurologic symptoms. Brain MRI was performed and showed different alterations suggesting the diagnosis of this infrequent sickness. (author) [es
Non-perturbative heavy quark effective theory. An application to semi-leptonic B-decays
International Nuclear Information System (INIS)
Della Morte, Michele; Heitger, Jochen; Simma, Hubert; Sommer, Rainer; Humboldt-Universitaet, Berlin
2015-01-01
We review a lattice strategy how to non-perturbatively determine the coefficients in the HQET expansion of all components of the heavy-light axial and vector currents, including 1/m h -corrections. We also discuss recent preliminary results on the form factors parameterizing semi-leptonic B-decays at the leading order in 1/m h .
Phanerozoic environments of black shale deposition and the Wilson Cycle
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J. Trabucho-Alexandre
2012-02-01
Full Text Available The spatial and temporal distribution of black shales is related to the development of environments in which they accumulate and to a propitious combination of environmental variables. In recent years, much has been done to improve our understanding of the mechanisms behind the temporal distribution of black shales in the Phanerozoic and of the environmental variables that result in their deposition. However, the interpretation of ancient black shale depositional environments is dominated by an oversimplistic set of three depositional models that do not capture their complexity and dynamics. These three models, the restricted circulation, the (open ocean oxygen minimum and the continental shelf models, are an oversimplification of the variety of black shale depositional environments that arise and coexist throughout the course of a basin's Wilson Cycle, i.e. the dynamic sequence of events and stages that characterise the evolution of an ocean basin, from the opening continental rift to the closing orogeny. We examine the spatial distribution of black shales in the context of the Wilson Cycle using examples from the Phanerozoic. It is shown that the geographical distribution of environments of black shale deposition and the position of black shales in the basin infill sequence strongly depend on basin evolution, which controls the development of sedimentary environments where black shales may be deposited. The nature of the black shales that are deposited, i.e. lithology and type of organic matter, also depends on basin evolution and palaeogeography. We propose that in studies of black shales more attention should be given to the sedimentary processes that have led to their formation and to the interpretation of their sedimentary environments.
Hagar, Joan C.; Dugger, Kate; Starkey, Edward E.
2007-01-01
Availability of food resources is an important factor in avian habitat selection. Food resources for terrestrial birds often are closely related to vegetation structure and composition. Identification of plant species important in supporting food resources may facilitate vegetation management to achieve objectives for providing bird habitat. We used fecal analysis to describe the diet of adult Wilson's Warblers (Wilsonia pusilla) that foraged in the understory of Douglas-fir (Pseudotsuga menziesii) forests in western Oregon during the breeding season. We sampled arthropods at the same sites where diet data were collected, and compared abundance and biomass of prey among seven common shrub species. Wilson's Warblers ate more caterpillars (Lepidoptera larvae), flies (Diptera), beetles (Coleoptera), and Homoptera than expected based on availability. Deciduous shrubs supported higher abundances of arthropod taxa and size classes used as prey by Wilson's Warblers than did evergreen shrubs. The development and maintenance of deciduous understory vegetation in conifer forests of the Pacific Northwest may be fundamental for conservation of food webs that support breeding Wilson's Warblers and other shrub-associated, insectivorous songbirds.
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Priyanka Basu
2015-06-01
Full Text Available This article examines texts by Elisabeth Wilson and Martin Heydrich written in 1914 at the University of Leipzig on the subject of ‘primitive’ ornament. Both synopsize the history and literature of this field from its beginnings in the nineteenth century to the time of their writing. This article considers how Wilson and Heydrich represent this history and how the field’s multidisciplinary practitioners perceived its pressing problems. Above all, Wilson and Heydrich set up a number of recurring oppositions between major approaches to ‘primitive’ art and ornament, between ‘materialist’ interpretation, allied with archaeology, symbolic interpretation practiced for the most part by ethnologists, and an ‘aesthetic’ approach, pursued by art theorists and focused on the psychological will of its creators. These issues and this configuration of approaches are further examined in one of August Schmarsow’s important essays on art history and ethnology.
Nonperturbative type IIB model building in the F-theory framework
Energy Technology Data Exchange (ETDEWEB)
Jurke, Benjamin Helmut Friedrich
2011-02-28
This dissertation is concerned with the topic of non-perturbative string theory, which is generally considered to be the most promising approach to a consistent description of quantum gravity. The five known 10-dimensional perturbative string theories are all interconnected by numerous dualities, such that an underlying non-perturbative 11-dimensional theory, called M-theory, is postulated. Due to several technical obstacles, little is known about the fundamental objects in this theory. There exists an alternative non-perturbative description to type IIB string theory, namely F-theory. Here the SL(2;Z) self-duality of IIB theory is geometrized in the form of an elliptic fibration over the space-time. Moreover, higher-dimensional objects like 7-branes are included via singularities into the geometric picture. This formally elegant description, however, requires significant technical effort for the construction of suitable compactification geometries, as many different aspects necessarily have to be dealt with at the same time. On the other hand, the generation of essential GUT building blocks like certain Yukawa couplings or spinor representations is easier compared to perturbative string theory. The goal of this study is therefore to formulate a unified theory within the framework of F-theory, that satisfies basic phenomenological constraints. Within this thesis, at first E3-brane instantons in type IIB string theory - 4-dimensional objects that are entirely wrapped around the invisible dimensions of space-time - are matched with M5-branes in F-theory. Such objects are of great importance in the generation of critical Yukawa couplings or the stabilization of the free parameters of a theory. Certain properties of M5-branes then allow to derive a new criterion for E3-branes to contribute to the superpotential. In the aftermath of this analysis, several compactification geometries are constructed and checked for basic properties that are relevant for semi
Nonperturbative type IIB model building in the F-theory framework
International Nuclear Information System (INIS)
Jurke, Benjamin Helmut Friedrich
2011-01-01
This dissertation is concerned with the topic of non-perturbative string theory, which is generally considered to be the most promising approach to a consistent description of quantum gravity. The five known 10-dimensional perturbative string theories are all interconnected by numerous dualities, such that an underlying non-perturbative 11-dimensional theory, called M-theory, is postulated. Due to several technical obstacles, little is known about the fundamental objects in this theory. There exists an alternative non-perturbative description to type IIB string theory, namely F-theory. Here the SL(2;Z) self-duality of IIB theory is geometrized in the form of an elliptic fibration over the space-time. Moreover, higher-dimensional objects like 7-branes are included via singularities into the geometric picture. This formally elegant description, however, requires significant technical effort for the construction of suitable compactification geometries, as many different aspects necessarily have to be dealt with at the same time. On the other hand, the generation of essential GUT building blocks like certain Yukawa couplings or spinor representations is easier compared to perturbative string theory. The goal of this study is therefore to formulate a unified theory within the framework of F-theory, that satisfies basic phenomenological constraints. Within this thesis, at first E3-brane instantons in type IIB string theory - 4-dimensional objects that are entirely wrapped around the invisible dimensions of space-time - are matched with M5-branes in F-theory. Such objects are of great importance in the generation of critical Yukawa couplings or the stabilization of the free parameters of a theory. Certain properties of M5-branes then allow to derive a new criterion for E3-branes to contribute to the superpotential. In the aftermath of this analysis, several compactification geometries are constructed and checked for basic properties that are relevant for semi
Borel and Stokes Nonperturbative Phenomena in Topological String Theory and c=1 Matrix Models
Pasquetti, Sara
2010-01-01
We address the nonperturbative structure of topological strings and c=1 matrix models, focusing on understanding the nature of instanton effects alongside with exploring their relation to the large-order behavior of the 1/N expansion. We consider the Gaussian, Penner and Chern-Simons matrix models, together with their holographic duals, the c=1 minimal string at self-dual radius and topological string theory on the resolved conifold. We employ Borel analysis to obtain the exact all-loop multi-instanton corrections to the free energies of the aforementioned models, and show that the leading poles in the Borel plane control the large-order behavior of perturbation theory. We understand the nonperturbative effects in terms of the Schwinger effect and provide a semiclassical picture in terms of eigenvalue tunneling between critical points of the multi-sheeted matrix model effective potentials. In particular, we relate instantons to Stokes phenomena via a hyperasymptotic analysis, providing a smoothing of the nonp...
Directory of Open Access Journals (Sweden)
Ricardo Massato Takemoto
2002-05-01
Full Text Available Four species of caligid copepods, parasites of Oligoplites palometa (Cuvier, 1833, O. saurus (Bloch & Schneider, 1801 and O. saliens (Bloch, 1793 (Osteichthyes: Carangidae from the Sepetiba Bay, coast of the state of Rio de Janeiro, Brazil, are presented. New geographical and host records for Caligus robustus Bassett-Smith, 1898, C. rufimaculatus Wilson, 1905, C. bonito Wilson, 1905 and Metacaligus rufus (Wilson, 1908 are given. Caligus oligoplitisi Carvalho, 1954 is considered a new junior synonym of C. robustus. Fishes of the genus Oligoplites are new host records for this species of copepod. Redescription and illustration of Tuxophorus caligodes Wilson, 1908, collected on the body surface of Oligoplites saliens, O. palometa and O. saurus, are provided.Quatro espécies de copépodes caligídeos, parasitos de Oligoplites palometa (Cuvier, 1833, O. saurus (Bloch & Schneider, 1801 e O. saliens (Bloch, 1793 (Osteichthyes, Carangidae da Baia de Sepetiba, litoral do Estado do Rio de Janeiro, Brasil, são descritos. São apresentados o registro de novo hospedeiro e nova distribuição geográfica para Caligus robustus Bassett-Smith, 1898, C. rufimaculatus Wilson, 1905, C. bonito Wilson, 1905 e Metacaligus rufus (Wilson, 1908. Caligus oligoplitisi Carvalho, 1954, é considerado novo sinônimo júnior de C. robustus. Tuxophorus caligodes Wilson, 1908, coletado na superfície do corpo de Oligoplites saliens, O. palometa e O. saurus é redescrito e ilustrado. Peixes do gênero Oligoplites são novos hospedeiros para estas espécies de copépodes.
A history of altruism focusing on Darwin, Allee and E.O. Wilson.
Domondon, Andrew T
2013-06-01
The problem of altruism refers to the apparent difficulty in reconciling the existence of altruists, individuals who reduce their own fitness to increase the fitness of others, with natural selection. A historical and philosophical overview of solutions to this apparent contradiction is presented through a close reading of the key texts of Charles Darwin, Warder C. Allee and Edward O. Wilson. Following an analysis of Darwin's explanation for altruism, I examine the ideas of group selection and kin selection advanced by Allee and Wilson, respectively, Attention is also given to the philosophical implications each associated with their respective solutions. Copyright © 2013 Elsevier Ltd. All rights reserved.
Wilson loops on three-manifolds and their M2-brane duals
International Nuclear Information System (INIS)
Farquet, Daniel; Sparks, James
2014-01-01
We compute the large N limit of Wilson loop expectation values for a broad class of N=2 supersymmetric gauge theories defined on a general class of background three-manifolds M_3, diffeomorphic to S"3. We find a simple closed formula which depends on the background geometry only through a certain supersymmetric Killing vector field. The supergravity dual of such a Wilson loop is an M2-brane wrapping the M-theory circle, together with a complex curve Σ_2 in a self-dual Einstein manifold M_4, whose conformal boundary is M_3. We show that the regularized action of this M2-brane also depends only on the supersymmetric Killing vector, precisely reproducing the large N field theory computation.
of the photon within QEDL and QEDM
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Bussone Andrea
2018-01-01
Full Text Available We compute the leading QED corrections to the hadronic vacuum polarization (HVP of the photon, relevant for the determination of leptonic anomalous magnetic moments, al. We work in the electroquenched approximation and use dynamical QCD configurations generated by the CLS initiative with two degenerate flavors of nonperturbatively O(a-improved Wilson fermions. We consider QEDL and QEDM to deal with the finite-volume zero modes. We compare results for the Wilson loops with exact analytical determinations. In addition we make sure that the volumes and photon masses used in QEDM are such that the correct dispersion relation is reproduced by the energy levels extracted from the charged pions two-point functions. Finally we compare results for pion masses and the HVP between QEDL and QEDM. For the vacuum polarization, corrections with respect to the pure QCD case, at fixed pion masses, turn out to be at the percent level.
Tuning up an oldtimer: hybrid Monte Carlo with Wilson fermions
International Nuclear Information System (INIS)
Schilling, K.; Hannemann, V.; Lippert, T.; Noeckel, B.
1995-01-01
We show that BiCGStab inversion algorithm helps to speed up by 50% the computation of the fermionic force inside the Hybrid Monte Carlo (HMC) simulation of full QCD with Wilson fermions, in the chiral regime of small quark masses. ((orig.))
Super Toeplitz operators and non-perturbative deformation quantization of supermanifolds
Energy Technology Data Exchange (ETDEWEB)
Borthwick, D.; Lesniewski, A.; Rinaldi, M. (Harvard Univ., Cambridge, MA (United States). Lyman Lab. of Physics); Klimek, S. (IUPUI, Indianapolis, IN (United States). Dept. of Mathematics)
1993-04-01
The purpose of this paper is to construct non-perturbative deformation quantizations of the algebras of smooth functions on Poisson supermanifolds. For the examples U[sup 1vertical] [sup stroke1] and C[sup mvertical] [sup stroken], algebras of super Toeplitz operators are defined with respect to certain Hilbert spaces of superholomorphic functions. Generators and relations for these algebras are given. The algebras can be thought of as algebras of 'quantized functions', and deformation conditions are proven which demonstrate the recovery of the super Piosson structures in a semi-classical limit. (orig.).
Physics beyond the standard model in the non-perturbative unification scheme
International Nuclear Information System (INIS)
Kapetanakis, D.; Zoupanos, G.
1990-01-01
The non-perturbative unification scenario predicts reasonably well the low energy gauge couplings of the standard model. Agreement with the measured low energy couplings is obtained by assuming certain kind of physics beyond the standard model. A number of possibilities for physics beyond the standard model is examined. The best candidates so far are the standard model with eight fermionic families and a similar number of Higgs doublets, and the supersymmetric standard model with five families. (author)
Multivariable biorthogonal continuous--discrete Wilson and Racah polynomials
International Nuclear Information System (INIS)
Tratnik, M.V.
1990-01-01
Several families of multivariable, biorthogonal, partly continuous and partly discrete, Wilson polynomials are presented. These yield limit cases that are purely continuous in some of the variables and purely discrete in the others, or purely discrete in all the variables. The latter are referred to as the multivariable biorthogonal Racah polynomials. Interesting further limit cases include the multivariable biorthogonal Hahn and dual Hahn polynomials
Perturbation theory and nonperturbative effects: a happy marriage?
International Nuclear Information System (INIS)
Chyla, J.
1992-01-01
Perturbation expansions in renormalized quantum 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 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. A close connection of this procedure to the Borel summation technique is demonstrated and its relation to conventional perturbation theory in fixed renormalization schemes elucidated. (author) 3 figs., 17 refs
A non-perturbative study of massive gauge theories
DEFF Research Database (Denmark)
Della Morte, Michele; Hernandez, Pilar
2013-01-01
and the lightest degrees of freedom are spin one vector particles with the same quantum numbers as the conserved current, we argue that the most general effective theory describing their low-energy dynamics must be a massive gauge theory. We present results of a exploratory numerical simulation of the model......We consider a non-perturbative formulation of an SU(2) massive gauge theory on a space-time lattice, which is also a discretised gauged non-linear chiral model. The lattice model is shown to have an exactly conserved global SU(2) symmetry. If a scaling region for the lattice model exists...... and find indications for the presence of a scaling region where both a triplet vector and a scalar remain light....
Wilson loops and its correlators with chiral operators in N = 2, 4 SCFT at large N
Sysoeva, E.
2018-03-01
In this paper we compute the vacuum expectation value of the Wilson loop and its correlators with chiral primary operators in N = 2, 4 superconformal U( N ) gauge theories at large N . After localization these quantities can be computed in terms of a deformed U( N ) matrix model. The Wilson loops we deal with are in the fundamental and symmetric representations.
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Monfort J.-P.
2006-11-01
Full Text Available La volabilité relative ait; =(yilxil(Y;lxi des constituants d'un mélange binaire a été mesurée à partir d'un nouveau dispositif expérimental, on reporte les données d'équilibre liquide-vapeur obtenues à 45'C de plusieurs binaires : toluène-acétoni-trile, benzène-acétonitrile et benzène-n-heptane. En ajustant à l'équation de Wilson les données expérimentales de «i/; de ces constituants ainsi que des volatilités relatives des constituants des mélanges d'hydrocarbures-alcools, obtenues dans un précédent travail, on calcule les paramètres énergétiques. La prédiction des points de bulle de mélanges binaires et ternaires obtenue à partir de ces paramètres est satisfaisante. La méthode expérimentale ainsi proposée convient particulièrement pour la sélection des solvant extractifs utilisés dans la distillation extractive. From a new expérimental method, relative volatilities aiti = (yilxil(yilxi for a binary mixture are obtained; vapor-liquid equilibrium data are presented for several systems, i.e. toluene-acétonitrile, benzene-acétonitrile and benzene-n-heptane at 45°C. The two adjustable energyparameters of thé Wilson équation, are obtained by adopting thé «,/j data for these binary mixtures and for alcohol-hydrocarbon mixtures previously studied. Theresults obtained in predicting bubble-pressure data for binary and ternary mixtures are consistent with experimental data.
Liver transplantation for Wilson disease.
Catana, Andreea M; Medici, Valentina
2012-01-27
The aim of this paper is to review the current status of liver transplantation (LT) for Wilson disease (WD), focusing on indications and controversies, especially in patients with neuropsychiatric disease, and on identification of acute liver failure (ALF) cases related to WD. LT remains the treatment of choice for patients with ALF, as initial presentation of WD or when anti-copper agents are stopped, and for patients with chronic liver disease progressed to cirrhosis, unresponsive to chelating medications or not timely treated with copper chelating agents. The indication for LT in WD remains highly debated in patients with progressive neurological deterioration and failure to improve with appropriate medical treatment. In case of Wilsonian ALF, early identification is key as mortality is 100% without emergency LT. As many of the copper metabolism parameters are believed to be less reliable in ALF, simple biochemical tests have been proposed for diagnosis of acute WD with good sensitivity and specificity. LT corrects copper metabolism and complications resulting from WD with excellent 1 and 5 year survival. Living related liver transplantation represents an alternative to deceased donor LT with excellent long-term survival, without disease recurrence. Future options may include hepatocyte transplantation and gene therapy. Although both of these have shown promising results in animal models of WD, prospective human studies are much needed to demonstrate their long-term beneficial effects and their potential to replace the need for medical therapy and LT in patients with WD.
Alien calculus and a Schwinger-Dyson equation: two-point function with a nonperturbative mass scale
Bellon, Marc P.; Clavier, Pierre J.
2018-02-01
Starting from the Schwinger-Dyson equation and the renormalization group equation for the massless Wess-Zumino model, we compute the dominant nonperturbative contributions to the anomalous dimension of the theory, which are related by alien calculus to singularities of the Borel transform on integer points. The sum of these dominant contributions has an analytic expression. When applied to the two-point function, this analysis gives a tame evolution in the deep euclidean domain at this approximation level, making doubtful the arguments on the triviality of the quantum field theory with positive β -function. On the other side, we have a singularity of the propagator for timelike momenta of the order of the renormalization group invariant scale of the theory, which has a nonperturbative relationship with the renormalization point of the theory. All these results do not seem to have an interpretation in terms of semiclassical analysis of a Feynman path integral.
Comments on correlation functions of large spin operators and null polygonal Wilson loops
Energy Technology Data Exchange (ETDEWEB)
Cardona, Carlos A., E-mail: cargicar@iafe.uba.ar [Instituto de Astronomia y Fisica del Espacio (CONICET-UBA), C.C. 67 - Suc. 28, 1428 Buenos Aires (Argentina); Physics Department, University of Buenos Aires, CONICET, Ciudad Universitaria, 1428 Buenos Aires (Argentina)
2013-02-11
We discuss the relation between correlation functions of twist-two large spin operators and expectation values of Wilson loops along light-like trajectories. After presenting some heuristic field theoretical arguments suggesting this relation, we compute the divergent part of the correlator in the limit of large 't Hooft coupling and large spins, using a semi-classical world-sheet which asymptotically looks like a GKP rotating string. We show this diverges as expected from the expectation value of a null Wilson loop, namely, as (ln{mu}{sup -2}){sup 2}, {mu} being a cut-off of the theory.
Comments on correlation functions of large spin operators and null polygonal Wilson loops
International Nuclear Information System (INIS)
Cardona, Carlos A.
2013-01-01
We discuss the relation between correlation functions of twist-two large spin operators and expectation values of Wilson loops along light-like trajectories. After presenting some heuristic field theoretical arguments suggesting this relation, we compute the divergent part of the correlator in the limit of large 't Hooft coupling and large spins, using a semi-classical world-sheet which asymptotically looks like a GKP rotating string. We show this diverges as expected from the expectation value of a null Wilson loop, namely, as (lnμ −2 ) 2 , μ being a cut-off of the theory.
Wilson line distributions in hot SU(2) gluodynamics
International Nuclear Information System (INIS)
Ilgenfritz, E.M.
1982-01-01
Monte-Carlo results concerning the order parameter related to confinement and its distribution from the point of view of the dilute instanton gas approximation are Discussed. Identified is a threshold effect in the Wilson line distribution with the onset of instantons and established is the relation between the temperature of instanton saturation and the confinement temperature. Some other details of our Monte-Carlo results are reported as well
Raising and Lowering Operators for Askey-Wilson Polynomials
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Siddhartha Sahi
2007-01-01
Full Text Available In this paper we describe two pairs of raising/lowering operators for Askey-Wilson polynomials, which result from constructions involving very different techniques. The first technique is quite elementary, and depends only on the ''classical'' properties of these polynomials, viz. the q-difference equation and the three term recurrence. The second technique is less elementary, and involves the one-variable version of the double affine Hecke algebra.
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Natália Casagrande Brabo
2010-06-01
Full Text Available TEMA: disartria na Doença de Wilson. PROCEDIMENTOS: estudo de caso de dois pacientes com o diagnóstico da doença, ambos adultos jovens, do sexo feminino e com seis anos de escolaridade. Quatro fonoaudiólogas realizaram a avaliação perceptivo-auditiva de modo independente, na qual foram investigados os seguintes parâmetros: tipo de voz, loudness, pitch, ataque vocal, instabilidade fonatória e ressonância. O grau de alteração de cada parâmetro foi mensurado através de uma escala analógico-visual. Além disso, foram obtidas medidas de inteligibilidade por transcrição ortográfica. A análise acústica foi realizada por meio do programa Praat, com a obtenção de medidas de frequência fundamental, de perturbação e ruído e medidas temporais. RESULTADOS: a fala de ambos os pacientes foi caracterizada por: redução do tempo máximo de fonação, voz soprosa e tensa, ataques vocais aspirados, instabilidade vocal, aumento de shimmer e proporção ruído-harmônico, hipernasalidade, redução da diadococinesia oral, da inteligibilidade e da velocidade da fala. Os resultados obtidos sugeriram que o paciente que cursa com a Doença de Wilson há mais tempo, apresentou prejuízo mais acentuado na maioria dos parâmetros perceptuais e acústicos analisados. CONCLUSÃO: foram identificadas manifestações comuns entre os casos, as quais podem constituir-se em traços característicos da fala de pacientes disártricos com Doença de Wilson. Todavia, diferenças também foram evidenciadas, as quais podem estar relacionadas ao tempo de evolução da doença.BACKGROUND: dysarthria in Wilson's disease. PROCEDURES: case study of two patients with disease's diagnosis, both young female adults, with six years of schooling. Perceptual analysis was done by four speech therapists. The following parameters were assessed: voice quality, loudness, pitch, vocal attack, vocal stability and resonance, as well as the degree of deviated parameters, measured
IUE observations of the evolution of Comet Wilson (1986l) - comparison with P/Halley
International Nuclear Information System (INIS)
Roettger, E.E.; Feldman, P.D.; A'hearn, M.F.; Festou, M.C.; Mcfadden, L.A.
1989-01-01
IUE observations of Comet Wilson from September 1986 to November 1987, through perihelion, allow a comparison to be conducted between this 'new' comet and the highly evolved P/Halley, at comparable heliocentric distances. The temporal decreases of both OH and dust in Comet Wilson near perihelion were monotonic and slow, by contrast to Comet Halley's rapid fluctuations. Despite these differences, relative gas abundances were similar within a factor of about 2 for comparable heliocentric and geocentric distances; this indicates that P/Halley's in situ gas measurements may be typical of comets generally. 33 refs
Urban research in a hostile setting: Godfrey Wilson in Broken Hill, Northern Rhodesia, 1938-1940
Directory of Open Access Journals (Sweden)
Karen Tranberg Hansen
Full Text Available Acknowledged for his pioneering urban anthropological research in Broken Hill through the publication of An Essay on the Economics of Detribalization in Northern Rhodesia (Parts I and II, 1940 and 1941, Godfrey Wilson's professional career was cut short by his death during World War II. The late 1990s transfer and cataloguing at the University of Cape Town of the Monica and Godfrey Wilson papers has made an enormously rich research archive accessible to the public. For the first time, Godfrey Wilson's notes from his fieldwork in Broken Hill enable us to examine his research project through his own observations. Based on a preliminary overview of these records and a tentative analysis of some of their contents, this article revisits the Broken Hill research project against the background of the published essay on the economics of detribalisation. Wilson's argument about temporary urbanisation is demonstrated through migration histories, information about length of stay in towns, and an analysis of the economics of urban livelihoods that focuses on wages including rations, household expenditures, and urban-rural transfers. But the published essay barely explains how in fact he conducted his field research. Although there are very few direct indications, we can infer some of his fieldwork practices and field methodology from notes that occasionally evoke an immediate sense of the trials and tribulations of everyday African life in Broken Hill in the early World War II years. How might experiences in the field have influenced Wilson's analysis? Overall, I discuss his work from two angles, first in the context of a time and place characterised by conflicting agendas, and secondly, in retrospect as the conceptual space and time of early World War II colonial Northern Rhodesia have yielded to different explanatory perspectives.
Anesthesia in Mowat-Wilson syndrome: information on 11 Italian patients
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Marianna Spunton
2018-03-01
Full Text Available Mowat-Wilson syndrome is a genetic disease caused by heterozygous mutations or deletions of the ZEB2 gene and characterized by typical clinical features. The congenital malformations typical of this syndrome call for early diagnostic and surgical procedures requiring general anesthesia, but few information about the anesthesiology management of such patients is available. We enrolled 11 families of patients with Mowat-Wilson syndrome who had undergone surgical or diagnostic procedures requiring general anesthesia, and sent them a retrospective questionnaire including 16 open questions about the procedures. They were further contacted by phone for a semi-structured interview. A total of 37 procedures requiring general anesthesia was reported in 11 patients. Only two patients reported anesthesia-related complications during the procedure. No true additional anesthesia-related risk was present for the patients with MW syndrome, besides difficult intubation, weaning and lower respiratory tract infection. Perception of risk, however, is derived by non-medical observation on the part of the parents.
Non-perturbative analytical solutions of the space- and time-fractional Burgers equations
International Nuclear Information System (INIS)
Momani, Shaher
2006-01-01
Non-perturbative analytical solutions for the generalized Burgers equation with time- and space-fractional derivatives of order α and β, 0 < α, β ≤ 1, are derived using Adomian decomposition method. The fractional derivatives are considered in the Caputo sense. The solutions are given in the form of series with easily computable terms. Numerical solutions are calculated for the fractional Burgers equation to show the nature of solution as the fractional derivative parameter is changed
A nonperturbative treatment of spin-dependent interactions of light and heavy quarkonia
International Nuclear Information System (INIS)
Schoeberl, F.
1986-01-01
We propose a nonrelativistic potential model with a regularized Coulomb potential at short range which leads to spin-dependent interactions which are at most as singular as 1/r. The Schroedinger equation is solved numerically including all spin-dependent interactions nonperturbatively. The predicted spectrum of light and heavy quarkonia is in remarkable agreement with experiment. Even the leptonic decay widths as well as the M1 transitions are in agreement with experiment. (Author)
Non-perturbative QCD correlation functions
Energy Technology Data Exchange (ETDEWEB)
Cyrol, Anton Konrad
2017-11-27
Functional methods provide access to the non-perturbative regime of quantum chromo- dynamics. Hence, they allow investigating confinement and chiral symmetry breaking. In this dissertation, correlation functions of Yang-Mills theory and unquenched two-flavor QCD are computed from the functional renormalization group. Employing a self-consistent vertex expansion of the effective action, Yang-Mills correlation functions are obtained in four as well as in three spacetime dimensions. To this end, confinement and Slavnov-Taylor identities are discussed. Our numerical results show very good agreement with corresponding lattice results. Next, unquenched two-flavor QCD is considered where it is shown that the unquenched two-flavor gluon propagator is insensitive to the pion mass. Furthermore, the necessity for consistent truncations is emphasized. Finally, correlation functions of finite-temperature Yang-Mills theory are computed in a truncation that includes the splitting of the gluon field into directions that are transverse and longitudinal to the heat bath. In particular, it includes the splitting of the three- and four-gluon vertices. The obtained gluon propagator allows to extract a Debye screening mass that coincides with the hard thermal loop screening mass at high temperatures, but is meaningful also at temperatures below the phase transition temperature.
Successful Splenectomy for Hypersplenism in Wilson's Disease: A Single Center Experience from China.
Li, Liang-Yong; Yang, Wen-Ming; Chen, Huai-Zhen; Wu, Yun-Hu; Fang, Xiang; Zhang, Jing; Wang, Zhen; Han, Yong-Sheng; Wang, Yu
2015-01-01
Splenomegaly and pancytopenia are common in Wilson's disease (WD) and splenectomy is one of the conventional treatments for splenomegaly and the associated pancytopenia. However, splenectomy remained controversial for hypersplenism in WD as it was reported that splenectomy leaded to serious emotional and neurological deterioration in WD patients with hypersplenism. In the current study, we present our experiences in 70 WD patients with hypersplenism who had undergone splenectomy, outlining the safety and efficacy of splenectomy in WD. The clinical database of 70 WD patients with hypersplenism who had undergone splenectomy in our hospital between 2009 and 2013 were reviewed and followed-up regularly. Before splenectomy, all the patients accepted a short period of anti-copper treatment with intravenous sodium 2, 3-dimercapto-1-propane sulfonate (DMPS). All the patients demonstrated a marked improvement in platelet and leucocyte counts after splenectomy. No severe postoperative complication was observed. In particular, none of the 37 patients with mixed neurologic and hepatic presentations experienced neurological deterioration after splenectomy, and none of the patients with only hepatic presentations newly developed neurological symptoms. During the one year follow-up period, no patient presented hepatic failure or hepatic encephalopathy, no hepatic patient newly developed neurological presentations, and only 3 patients with mixed neurologic and hepatic presentations suffered neurological deterioration and these 3 patients had poor compliance of anti-copper treatment. Quantative analysis of the neurological symptoms in the 37 patients using the Unified Wilson's Disease Rating Scale (UWDRS) showed that the neurological symptoms were not changed in a short-term of one week after splenectomy but significantly improved in a long-term of one year after splenectomy. Additionally, compared to that before splenectomy, the esophageal gastric varices in most patients
Eugene Onegin the Cold War Monument: How Edmund Wilson Quarreled with Vladimir Nabokov
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Tim Conley
2014-01-01
Full Text Available The tale of how Edmund Wilson quarreled with Vladimir Nabokov over the latter’s 1964 translation of Eugene Onegin can be instructively read as a politically charged event, specifically a “high culture” allegory of the Cold War. Dissemination of anti-Communist ideals (often in liberal and literary guises was the mandate of the Congress for Cultural Freedom, whose funding and editorial initiatives included the publication of both pre-Revolution Russian literature and, more notoriously, the journal Encounter (1953-1990, where Nabokov’s fiery “Reply” to Wilson appeared. This essay outlines the propaganda value of the Onegin debate within and to Cold War mythology.
Mandelstam cuts and light-like Wilson loops in N=4 SUSY
Energy Technology Data Exchange (ETDEWEB)
Lipatov, L.N. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; St. Petersburg Inst. of Nuclear Physics, Gatchina (Russian Federation); Prygarin, A. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik
2010-08-15
We perform an analytic continuation of the two-loop remainder function for the six-point planar MHV amplitude in N=4 SUSY, found by Goncharov, Spradlin, Vergu and Volovich from the light-like Wilson loop representation. The remainder function is continued into a physical region, where all but two energy invariants are negative. It turns out to be pure imaginary in the multi-Regge kinematics, which is in an agreement with the predictions based on the Steinmann relations for the Regge poles and Mandelstam cut contributions. The leading term reproduces correctly the expression calculated by one of the authors in the BFKL approach, while the subleading term presents a result, that was not yet found with the use of the unitarity techniques. This supports the applicability of the Wilson loop approach to the planar MHV amplitudes in N=4 SUSY. (orig.)
Mandelstam cuts and light-like Wilson loops in N=4 SUSY
International Nuclear Information System (INIS)
Lipatov, L.N.; Prygarin, A.
2010-08-01
We perform an analytic continuation of the two-loop remainder function for the six-point planar MHV amplitude in N=4 SUSY, found by Goncharov, Spradlin, Vergu and Volovich from the light-like Wilson loop representation. The remainder function is continued into a physical region, where all but two energy invariants are negative. It turns out to be pure imaginary in the multi-Regge kinematics, which is in an agreement with the predictions based on the Steinmann relations for the Regge poles and Mandelstam cut contributions. The leading term reproduces correctly the expression calculated by one of the authors in the BFKL approach, while the subleading term presents a result, that was not yet found with the use of the unitarity techniques. This supports the applicability of the Wilson loop approach to the planar MHV amplitudes in N=4 SUSY. (orig.)
Clinical presentation and mutations in Danish patients with Wilson disease
DEFF Research Database (Denmark)
Møller, Lisbeth Birk; Horn, Nina; Jeppesen, Tina Dysgaard
2011-01-01
This study describes the clinical presentation and diagnosis in all Danish patients (49, 41 unrelated) with Wilson disease (WND). On the basis of the number of diagnosed patients from 1990-2008, the prevalence was estimated to be 1:49¿500. Among routinely used diagnostic tests, none were...
Clinical presentation and mutations in Danish patients with Wilson disease
DEFF Research Database (Denmark)
Møller, Lisbeth Birk; Horn, Nina; Jeppesen, Tina Dysgaard
2011-01-01
This study describes the clinical presentation and diagnosis in all Danish patients (49, 41 unrelated) with Wilson disease (WND). On the basis of the number of diagnosed patients from 1990-2008, the prevalence was estimated to be 1:49 500. Among routinely used diagnostic tests, none were...
Rose, F.; Dupuis, N.
2018-05-01
We present an approximation scheme of the nonperturbative renormalization group that preserves the momentum dependence of correlation functions. This approximation scheme can be seen as a simple improvement of the local potential approximation (LPA) where the derivative terms in the effective action are promoted to arbitrary momentum-dependent functions. As in the LPA, the only field dependence comes from the effective potential, which allows us to solve the renormalization-group equations at a relatively modest numerical cost (as compared, e.g., to the Blaizot-Mendéz-Galain-Wschebor approximation scheme). As an application we consider the two-dimensional quantum O(N ) model at zero temperature. We discuss not only the two-point correlation function but also higher-order correlation functions such as the scalar susceptibility (which allows for an investigation of the "Higgs" amplitude mode) and the conductivity. In particular, we show how, using Padé approximants to perform the analytic continuation i ωn→ω +i 0+ of imaginary frequency correlation functions χ (i ωn) computed numerically from the renormalization-group equations, one can obtain spectral functions in the real-frequency domain.
Multiphoton transitions in semiconductors in the non-perturbative approach
International Nuclear Information System (INIS)
Iqbal, M.Z.; Hassan, A.R.
1987-09-01
Transition rates for multiphoton absorption via direct band-to-band excitation have been calculated using a non-perturbative approach due to Jones and Reiss, based on the Volkov type final state wave functions. Both cases of parabolic and non-parabolic energy bands have been included in our calculations. Absorption coefficients have been obtained for the cases of plane polarized and circularly polarized light. In particular, two-photon absorption coefficients are derived for the two cases of polarization for the parabolic band approximation as well as for non-parabolic bands and compared with the results based on perturbation theory. Numerical estimates of the two photon absorption coefficients resulting from our calculations are also provided. (author). 10 refs, 1 tab
Fogg, Ryan; Kutikov, Alexander; Uzzo, Robert G; Canter, Daniel
2011-09-01
President Woodrow Wilson was never able to gain ratification of the Treaty of Versailles, the peace accord to end World War I. Before he could convince the American people of the importance of ratification, Wilson suffered a stroke followed by life threatening urinary sepsis due to urinary retention, and was treated by the father of modern urology, Hugh Hampton Young. The effects of these health problems are examined in the context of their implications on international affairs. Biographical sources and primary documentation of Wilson's physicians were reviewed to determine the effect of Wilson's stroke on his voiding habits. Hugh Hampton Young's evaluation and decision making is examined in depth. In the fall of 1919 President Wilson was recovering from a stroke. Shortly after the stroke his preexisting voiding dysfunction progressed to urinary retention from which urinary sepsis developed. Hugh Hampton Young advised on Wilson's case and counseled patience over surgery. The President began voiding spontaneously and recovered from sepsis. The illness left him severely weakened and unable to mount an aggressive campaign to persuade the U.S. Senate of the importance of ratifying the Treaty of Versailles. His personal physician, Admiral Cary T. Grayson, stated that the President was mentally never the same after the sepsis. Wilson's voiding dysfunction contributed to his inability to win approval for the Treaty of Versailles and the League of Nations. As a result, the United States returned to a policy of isolationism and Europe plunged into 2 decades of upheaval, leading to World War II. Copyright © 2011 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.
The running coupling from the QCD Schrödinger functional a one-loop analysis
Sint, S; Sint, Stefan; Sommer, Rainer
1996-01-01
Starting from the Schr\\"odinger functional, we give a non-perturbative definition of the running coupling constant in QCD. The spatial boundary conditions for the quark fields are chosen such that the massless Dirac operator in the classical background field has a large smallest eigenvalue. At one-loop order of perturbation theory, we determine the matching coefficient to the \\MSbar-scheme and discuss the quark mass effects in the \\beta-function. To this order, we also compute the Symanzik improvement coefficient necessary to remove the \\Oa lattice artefacts originating from the boundaries. For reasonable lattice resolutions and the standard Wilson action, lattice artefacts are found to be only weakly dependent on the lattice spacing a, while they vanish quickly with the improved action of Sheikholeslami and Wohlert.
SU(2) string tension from large Wilson loops
International Nuclear Information System (INIS)
Karsch, F.; Lang, C.B.
1984-01-01
We determine expectation values of Wilson loops and correlations of Polyakov loops on lattices of size 10 X 16 3 and 8 X 16 3 at β values 2.25 and 2.375. Utilizing a recently proposed method to reduce the variance of loop expectation values, we are able to measure loops up to 6 X 6. We find Λsub(L) = 0.0151 +- 0.0006√sub(K) at β = 2.375. (orig.)
Pontes e rupturas no fabular de Wilson Bueno
Furquim, Fulvia Maria Giaretta de Almeida
2008-01-01
O trabalho tem por objetivo analisar tres obras contemporaneas do escritor paranaense Wilson Bueno (1949- ), que fazem parte de um projeto literario, em que as personagens sao apresentadas de uma visao inicialmente plural, como se apenas uma delas pudesse ser a representacao do todo, para uma optica individualista, caracteristica de um sistema capitalista. Sao elas: Manual de Zoofilia (1991), Jardim Zoologico (1999) e Cachorrros do Ceu (2005). O escritor contemporaneo segue a tradicao dos bes...
[Wilson's principles--a base of modern teratology].
Burdan, Franciszek; Bełzek, Artur; Szumiło, Justyna; Dudka, Jarosław; Korobowicz, Agnieszka; Tokarska, Edyta; Klepacz, Lidia; Bełzek, Marta; Klepacz, Robert
2006-03-01
Wilson's principles were formulated after thalidomide tragedy. They become a fundamental for teratological studies with drugs and other factors that may disturb fetal development. It is postulated that susceptibility to teratogen depends on the genotype and developmental stage of the conceptus. Teratogenic agents act in specific manner on developing cells and tissues. The exposition depends on the agent's nature and availability. Manifestations of deviant development depends on the dosage and exposure frequency. In case of abnormal development the final manifestations include death of embryo or fetus, malformation, growth retardation and functional disorder.
Non-perturbative supersymmetry anomaly in supersymmetric QCD
International Nuclear Information System (INIS)
Shamir, Y.
1991-03-01
The zero modes of the Dirac operator in an instanton and other topologically non-trivial backgrounds are unstable in a large class of massless or partially massless supersymmetric gauge theories. We show that under a generic perturbation of the scalar fields all zero modes become resonances, and discuss the ensuing breakdown of conventional perturbation theory. As a result, despite of the presence of massless fermions, the field theoretic tunneling amplitude is not suppressed. In massless supersymmetric QCD with N c ≤ N f the effective potential is found to be negative and monotonically increasing in the weak coupling regime for scalar VEVs which lie on the perturbatively flat directions. Consequently, massless supersymmetric QCD with N c ≤ N f exhibits a non-perturbative supersymmetry anomaly and exists in a strongly interacting phase which closely resembles ordinary QCD. The same conclusions apply if small masses are added to the lagrangian and the massless limit is smooth. (author). 21 refs, 5 figs
Off-shell amplitudes as boundary integrals of analytically continued Wilson line slope
International Nuclear Information System (INIS)
Kotko, P.; Serino, M.; Staśto, A.M.
2016-01-01
One of the methods to calculate tree-level multi-gluon scattering amplitudes is to use the Berends-Giele recursion relation involving off-shell currents or off-shell amplitudes, if working in the light cone gauge. As shown in recent works using the light-front perturbation theory, solutions to these recursions naturally collapse into gauge invariant and gauge-dependent components, at least for some helicity configurations. In this work, we show that such structure is helicity independent and emerges from analytic properties of matrix elements of Wilson line operators, where the slope of the straight gauge path is shifted in a certain complex direction. This is similar to the procedure leading to the Britto-Cachazo-Feng-Witten (BCFW) recursion, however we apply a complex shift to the Wilson line slope instead of the external momenta. While in the original BCFW procedure the boundary integrals over the complex shift vanish for certain deformations, here they are non-zero and are equal to the off-shell amplitudes. The main result can thus be summarized as follows: we derive a decomposition of a helicity-fixed off-shell current into gauge invariant component given by a matrix element of a straight Wilson line plus a reminder given by a sum of products of gauge invariant and gauge dependent quantities. We give several examples realizing this relation, including the five-point next-to-MHV helicity configuration.
δ expansion for a quantum field theory in the nonperturbative regime
International Nuclear Information System (INIS)
Bender, C.M.; Milton, K.A.; Pinsky, S.S.; Simmons, L.M. Jr.
1990-01-01
The δ expansion, a recently proposed nonperturbative technique in quantum field theory, is used to calculate the dimensionless renormalized coupling constant of a λ(var-phi 2 ) 1+δ quantum field theory in d-dimensional space-time at the critical point defined by λ→∞ with the renormalized mass held fixed. The calculation is performed to leading order in δ and compared with previous lattice strong-coupling calculations. The numerical results are good and provide new evidence that the theory in four dimensions is free for all δ
Two-dimensional sigma models: modelling non-perturbative effects of gauge theories
International Nuclear Information System (INIS)
Novikov, V.A.; Shifman, M.A.; Vainshtein, A.I.; Zakharov, V.I.
1984-01-01
The review is devoted to a discussion of non-perturbative effects in gauge theories and two-dimensional sigma models. The main emphasis is put on supersymmetric 0(3) sigma model. The instanton-based method for calculating the exact Gell-Mann-Low function and bifermionic condensate is considered in detail. All aspects of the method in simplifying conditions are discussed. The basic points are: the instanton measure from purely classical analysis; a non-renormalization theorem in self-dual external fields; existence of vacuum condensates and their compatibility with supersymmetry
Directory of Open Access Journals (Sweden)
Catarina Matos
2015-06-01
Full Text Available Background: Wilson`s disease is a rare autosomal recessive disorder characterized by a change in the transport of copper in the liver, with progressive accumulation in this and other organs such as brain, kidney and cornea. Phenotypic expression of the disease varies widely and can range from elevated liver enzymes, fatty liver or gallstones in asymptomatic patients, to cirrhosis and fulminant hepatic failure, or disabling neuropsychiatric disease. Aim: To characterize a sample of patients with Wilson´s disease. Patients and Methods: Retrospective survey including children diagnosed with Wilson´s disease between 2002 and 2011 according to the criteria of the European Association for the Study of the Liver (2012. We analyzed family history; age, clinical data, imaging and histology at the time of diagnosis; genetic analysis; treatment and side effects; follow-up and current status. Results: We identified five patients. Three had a family history of disease. All were asymptomatic and had maintained raised liver enzymes. No patient had clinical stigmata of chronic liver disease. One female patient had overweight. All were treated with D-penicillamine, withdrawn in two patients because of side effects. Currently all patients remain asymptomatic, without evidence of progression of liver disease, with a median follow-up of 5 years and 3 months. Discussion: Our series show that Wilson´s disease may be present with raised liver enzymes in asymptomatic children. The overweight patient alerts us to screen the disease in overweight/obese patients with raised liver enzymes and/or steatosis persisting for more than six months after weight loss.
Directory of Open Access Journals (Sweden)
Stephania de Andrade Sócio
2010-06-01
Full Text Available OBJETIVO: Descrever as formas de apresentação, as alterações laboratoriais ao diagnóstico e o tratamento de crianças e adolescentes com doença de Wilson. MÉTODOS: Estudo descritivo e retrospectivo de 17 crianças e adolescentes com doença de Wilson atendidos no Ambulatório de Hepatologia Pediátrica do Hospital das Clínicas da Universidade Federal de Minas Gerais no período de 1985 a 2008. Os dados foram coletados dos prontuários e durante as consultas ambulatoriais. RESULTADOS: A idade ao diagnóstico variou de 2,8 a 15,1 anos, com média de 8,8±0,9 anos. A forma de apresentação predominante foi hepática (53%, seguida por assintomáticos provenientes de triagem familiar. O anel de Kayser-Fleischer foi encontrado em 41% dos pacientes. A ceruloplasmina encontrava-se alterada em 15/17 pacientes e o cobre urinário variou de 24 a 1000mcg/24h (mediana: 184mcg/24h. O tratamento instituído foi a D-penicilamina. Observaram-se efeitos colaterais em cinco crianças, sem necessidade de interrupção ou troca da medicação. As respostas clínica e laboratorial, com níveis normais de aminotransferases, foram evidenciadas em 14 pacientes após mediana de 10,7 meses de tratamento. Três crianças morreram (uma por hepatite fulminante e duas com complicações da insuficiência hepática grave, apesar do tratamento. CONCLUSÕES: A doença de Wilson é rara na faixa etária pediátrica. A forma de apresentação predominante é a hepática. Seu diagnóstico se baseia principalmente em dosagem de ceruloplasmina baixa, cobre livre e cobre em urina de 24 horas elevados, mas exige alto grau de suspeição. Apresenta boa resposta e tolerância ao tratamento medicamentoso.OBJECTIVE: To describe clinical symptoms, laboratory findings at diagnosis and treatment of children and adolescents with Wilson's disease. METHODS: This is a descriptive and retrospective study of a series of 17 children and adolescents with Wilson's disease, assited at the
Quasilocal quark models as effective theory of non-perturbative QCD
International Nuclear Information System (INIS)
Andrianov, A.A.
2006-01-01
We consider the Quasilocal Quark Model of NJL type (QNJLM) as effective theory of non-perturbative QCD including scalar (S), pseudo-scalar (P), vector (V) and axial-vector (A) four-fermion interaction with derivatives. In the presence of a strong attraction in the scalar channel the chiral symmetry is spontaneously broken and as a consequence the composite meson states are generated in all channels. With the help of Operator Product Expansion the appropriate set of Chiral Symmetry Restoration (CSR) Sum Rules in these channels are imposed as matching rules to QCD at intermediate energies. The mass spectrum and some decay constants for ground and excited meson states are calculated
Energy Technology Data Exchange (ETDEWEB)
Palombi, F. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Gruppe Theorie; Papinutto, M. [Istituto Nazionale di Fisica Nucleare, Rome (Italy); Pena, C. [European Organization for Nuclear Research, Geneva (Switzerland). Theoretical Physics Div.; Wittig, H. [Mainz Univ. (Germany). Inst. fuer Kernphysik
2006-04-15
We discuss the renormalisation properties of the complete set of {delta}B=2 four-quark operators with the heavy quark treated in the static approximation. We elucidate the role of heavy quark symmetry and other symmetry transformations in constraining their mixing under renormalisation. By employing the Schroedinger functional, a set of non-perturbative renormalisation conditions can be defined in terms of suitable correlation functions. As a first step in a fully non-perturbative determination of the scale-dependent renormalisation factors, we evaluate these conditions in lattice perturbation theory at one loop. Thereby we verify the expected mixing patterns and determine the anomalous dimensions of the operators at NLO in the Schroedinger functional scheme. Finally, by employing twisted-mass QCD it is shown how finite subtractions arising from explicit chiral symmetry breaking can be avoided completely. (Orig.)
International Nuclear Information System (INIS)
Palombi, F.; Pena, C.; Wittig, H.
2006-04-01
We discuss the renormalisation properties of the complete set of ΔB=2 four-quark operators with the heavy quark treated in the static approximation. We elucidate the role of heavy quark symmetry and other symmetry transformations in constraining their mixing under renormalisation. By employing the Schroedinger functional, a set of non-perturbative renormalisation conditions can be defined in terms of suitable correlation functions. As a first step in a fully non-perturbative determination of the scale-dependent renormalisation factors, we evaluate these conditions in lattice perturbation theory at one loop. Thereby we verify the expected mixing patterns and determine the anomalous dimensions of the operators at NLO in the Schroedinger functional scheme. Finally, by employing twisted-mass QCD it is shown how finite subtractions arising from explicit chiral symmetry breaking can be avoided completely. (Orig.)
International Nuclear Information System (INIS)
Walter, M.G.A.
2004-02-01
We consider several examples of a special class of heterotic compactifications, i.e. heterotic E 8 x E 8 orbifolds with Wilson line backgrounds. By developing a local perspective we show that a brane world like picture emerges. As an important result we prove that the local massless spectrum at such a brane can always be traced back to the global spectrum of a (different) orbifold without Wilson lines. One particular implication of this result is that the use of (discrete) Wilson lines for the construction of phenomenologically interesting models has to be rethought. We show that stringy constraints render the brane spectra consistent. Using our local picture we are able to compute the local anomalies appearing at the different branes for our examples and show that they can all be cancelled by a local version of the Green-Schwarz mechanism at the same time. (orig.)
Nonperturbative QCD corrections to electroweak observables
Energy Technology Data Exchange (ETDEWEB)
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.
Wilson cycle passive margins: Control of orogenic inheritance on continental breakup
DEFF Research Database (Denmark)
Petersen, Kenni D.; Schiffer, Christian
2016-01-01
Abstract Rifts and passive margins often develop along old suture zones where colliding continents merged during earlier phases of the Wilson cycle. For example, the North Atlantic formed after continental break-up along sutures formed during the Caledonian and Variscan orogenies. Even though suc...
A non-perturbative analysis in finite volume gauge theory
International Nuclear Information System (INIS)
Koller, J.; State Univ. of New York, Stony Brook; Van Baal, P.; State Univ. of New York, Stony Brook
1988-01-01
We discuss SU(2) gauge theory on a three-torus using a finite volume expansion. Our discovery of natural coordinates allows us to obtain continuum results in a region where Monte Carlo data are also available. The obtained results agree well with the perturbative and semiclassical analysis for small volumes, and there is fair agreement with the Monte Carlo results in intermediate volumes. The simple picture which emerges for the approximate low energy dynamics is that of three interacting particles enclosed in a sphere, with zero total 'angular momentum'. The validity of an adiabatic approximation is investigated. The fundamentally new understanding gained, is that non-perturbative dynamics can be incorporated by imposing boundary conditions which arise through the nontrivial topology of configuration space. (orig.)
Non-perturbative approach for laser radiation interactions with solids
International Nuclear Information System (INIS)
Jalbert, G.
1985-01-01
Multiphoton transitions in direct-gap crystals are studied considering non-perturbative approaches. Two methods currently used for atoms and molecules are revised, generalized and applied to solids. In the first one, we construct an S-matrix which incorporates the eletromagnetic field to all orders in an approximated way leading to analytical solution for the multiphoton transition rates. In the second one, the transition probability is calculated within the Bloch-Floquet formalism applieed to the specific case of solids. This formalism is interpreted as a classical approximation to the quantum treatment of the field. In the weak field limit, we compare our results with the usual perturbation calculations. We also incorporate, in the first approach, the non homogeneity and the multimodes effects of a real laser. (author) [pt
Matsudo, Ryutaro; Kondo, Kei-Ichi
2015-12-01
We give a gauge-independent definition of magnetic monopoles in the S U (N ) Yang-Mills theory through the Wilson loop operator. For this purpose, we give an explicit proof of the Diakonov-Petrov version of the non-Abelian Stokes theorem for the Wilson loop operator in an arbitrary representation of the S U (N ) gauge group to derive a new form for the non-Abelian Stokes theorem. The new form is used to extract the magnetic-monopole contribution to the Wilson loop operator in a gauge-invariant way, which enables us to discuss confinement of quarks in any representation from the viewpoint of the dual superconductor vacuum.
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.
International Nuclear Information System (INIS)
Wells, J.C.; Oberacker, V.E.; Umar, A.S.
1993-01-01
The prospect of new colliding-beam accelerators capable of producing collisions of highly stripped high-Z ions, at fixed-target energies per nucleon up to 20 TeV or more, has motivated much interest in lepton-pair production from the QED vacuum. The time-dependent and essentially classical electromagnetic fields involved in such collisions contain larger Fourier components which give rise to sizable lepton-pair production in addition to many other exotic particles. The process of electron-positron production with electron capture is a principal beam-loss mechanism for highly charged ions in a storage ring. In this process, the electron is created in a bound state of one of the participant heavy ions (most likely the 1s state), thus changing the ion's charge state and causing it to be deflected out of the beam. There is a long and sometimes controversial history concerning the use of perturbative methods in studying electromagnetic lepton-pair production; however, reliable perturbative calculations have been used as input into design models for the Relativistic Heavy-Ion Collider (RHIC). Applying perturbation theory to these processes at high energies and small impact parameters results in probabilities which violate unitarity, and cross sections which violate the Froissart bound. This evidence, along with the initial nonperturbative studies, suggests that higher-order QED effects will be important for extreme relativistic collisions. Clearly, large nonperturbative effects in electron-pair production with capture would have important implications for RHIC. In this paper, the authors briefly discuss recent progress in nonperturbative studies of the capture problem. In Section 2, they state the Dirac equation for a lepton in the time-dependent external field of a heavy ion which must be solved to compute lepton-capture probabilities. Section 4 surveys results from recent applications of coupled-channel and lattice techniques to the lepton-capture problem
Light quark masses with Nf = 2 Wilson fermions
International Nuclear Information System (INIS)
Eicker, N.; Lippert, Th.; Orth, B.; Schilling, K.
2002-01-01
We present new data on the mass of the light and strange quarks from SESAM/TχL. The results were obtained on lattice-volumes of 16 3 x 32 and 24 3 x 40 points, with the possibility to investigate finite-size effects. Since the SESAM/TχL ensembles at β = 5.6 have been complemented by configurations with β = 5.5, moreover, we are now able to attempt the continuum extrapolation (CE) of the quark masses with standard Wilson fermions
Towards a non-perturbative matching of HQET and QCD with dynamical light quarks
International Nuclear Information System (INIS)
Della Morte, M.; Simma, H.; Sommer, R.
2007-10-01
We explain how the strategy of solving renormalization problems in HQET non-perturbatively by a matching to QCD in finite volume can be implemented to include dynamical fermions. As a primary application, some elements of an HQET computation of the mass of the b-quark beyond the leading order with N f =2 are outlined. In particular, the matching of HQET and QCD requires relativistic QCD simulations in a volume with L∼0.5 fm, which will serve to quantitatively determine the heavy quark mass dependence of heavy-light meson observables in the continuum limit of finite-volume two-flavour lattice QCD. As a preparation for the latter, we report on our determination of the renormalization constants and improvement coefficients relating the renormalized current and subtracted bare quark mass in the relevant weak coupling region. The calculation of these coefficients employs a constant physics condition in the Schrodinger functional scheme, where the box size L is fixed by working at a prescribed value of the renormalized coupling. (orig.)
Towards a non-perturbative matching of HQET and QCD with dynamical light quarks
Energy Technology Data Exchange (ETDEWEB)
Della Morte, M. [CERN, Geneva (Switzerland). Physics Dept.; Fritzsch, P.; Heitger, J. [Muenster Univ. (Germany). Inst. fuer Theoretische Physik 1; Meyer, H.B. [Massachusets Institute of Technology, Center for Theoretical Physics, Cambridge, MA (United States); Simma, H.; Sommer, R. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)
2007-10-15
We explain how the strategy of solving renormalization problems in HQET non-perturbatively by a matching to QCD in finite volume can be implemented to include dynamical fermions. As a primary application, some elements of an HQET computation of the mass of the b-quark beyond the leading order with N{sub f} =2 are outlined. In particular, the matching of HQET and QCD requires relativistic QCD simulations in a volume with L{approx}0.5 fm, which will serve to quantitatively determine the heavy quark mass dependence of heavy-light meson observables in the continuum limit of finite-volume two-flavour lattice QCD. As a preparation for the latter, we report on our determination of the renormalization constants and improvement coefficients relating the renormalized current and subtracted bare quark mass in the relevant weak coupling region. The calculation of these coefficients employs a constant physics condition in the Schrodinger functional scheme, where the box size L is fixed by working at a prescribed value of the renormalized coupling. (orig.)
Exponentiation for products of Wilson lines within the generating function approach
International Nuclear Information System (INIS)
Vladimirov, A.A.
2015-01-01
We present the generating function approach to the perturbative exponentiation of correlators of a product of Wilson lines and loops. The exponentiated expression is presented in closed form as an algebraic function of correlators of known operators, which can be seen as a generating function for web diagrams. The expression is naturally split onto two parts: the exponentiation kernel, which accumulates all non-trivial information about web diagrams, and the defect of exponentiation, which reconstructs the matrix exponent and is a function of the exponentiation kernel. The detailed comparison of the presented approach with existing approaches to exponentiation is presented as well. We also give examples of calculations within the generating function exponentiation, namely, we consider different configurations of light-like Wilson lines in the multi-gluon-exchange-webs (MGEW) approximation. Within this approximation the corresponding correlators can be calculated exactly at any order of perturbative expansion by only algebraic manipulations. The MGEW approximation shows violation of the dipole formula for infrared singularities at three-loop order.
A conditioning technique for matrix inversion for Wilson fermions
International Nuclear Information System (INIS)
DeGrand, T.A.
1988-01-01
I report a simple technique for conditioning conjugate gradient or conjugate residue matrix inversion as applied to the lattice gauge theory problem of computing the propagator of Wilson fermions. One form of the technique provides about a factor of three speedup over an unconditioned algorithm while running at the same speed as an unconditioned algorithm. I illustrate the method as it is applied to a conjugate residue algorithm. (orig.)
International Nuclear Information System (INIS)
Giavarini, G.; Martin, C.P.; Ruiz Ruiz, F.
1993-01-01
We show that the renormalized vacuum expectation value of the Wilson loop for topologically massive abelian gauge theory in bbfR 3 can be defined so that its large-mass limit be the renormalized vaccum expectation value of the Wilson loop for abelian Chern-Simons theory also in bbfR 3 . (orig.)
Non-perturbative studies of QCD at small quark masses
Energy Technology Data Exchange (ETDEWEB)
Wennekers, J.
2006-07-15
We investigate the quenched approximation of lattice QCD with numerical simulations of Ginsparg-Wilson fermions, which are a fermion discretisation with exact chiral symmetry. We compute the renormalisation constant of the scalar density, which allows to extrapolate the chiral condensate to the continuum limit. Furthermore we match lattice results of matrix elements describing hadronic kaon decays to Chiral Perturbation Theory in finite volume and at almost vanishing quark mass. The resulting low-energy constants in the considered SU(4)-flavour symmetric case indicate a substantial contribution of low scale QCD effects to the {delta}I = 1/2 rule. (Orig.)
Wilson Loop and related strings for the instanton and their variational derivatives
International Nuclear Information System (INIS)
Bollini, C.G.; Giambiagi, J.J.; Tiomno, J.
1980-05-01
Ordered integrals along arcs (or circles) and segments for the instanton are computed. They are to obtain variational and partial derivatives for open an d closed strings. The D'Alembertian for wilson loops is also computed. (Author) [pt
Non-perturbative phenomena in QCD vacuum, hadrons, and quark-gluon plasma
International Nuclear Information System (INIS)
Shuryak, E.V.
1983-01-01
These lectures provide a brief review of recent progress in non-perturbative quantum chromodynamics (QCD). They are intended for non specialists, mainly experimentalists. The main object of discussion, the QCD vacuum, is a rather complicated medium. It may be studied either by infinitesimal probes producing microscopic excitations (=hadrons), or by finite excitations (say, heating some volume to a given temperature T). In the latter case, some qualitative changes (phase transitions) should take place. A summary is given of the extent to which such phenomena can be observed in the laboratory by proton-proton, proton-nucleus, and nucleus-nucleus collisions. (orig.)
Nonperturbative time-convolutionless quantum master equation from the path integral approach
International Nuclear Information System (INIS)
Nan Guangjun; Shi Qiang; Shuai Zhigang
2009-01-01
The time-convolutionless quantum master equation is widely used to simulate reduced dynamics of a quantum system coupled to a bath. However, except for several special cases, applications of this equation are based on perturbative calculation of the dissipative tensor, and are limited to the weak system-bath coupling regime. In this paper, we derive an exact time-convolutionless quantum master equation from the path integral approach, which provides a new way to calculate the dissipative tensor nonperturbatively. Application of the new method is demonstrated in the case of an asymmetrical two-level system linearly coupled to a harmonic bath.
A new scheme for the running coupling constant in gauge theories using Wilson loops
Energy Technology Data Exchange (ETDEWEB)
Kurachi, Masafumi [Los Alamos National Laboratory; Bilgici, Erek [AUSTRIA; Flachi, Antonion [KYOTO UNIV; Itou, Etsuko [KOGAKUIN UNIV; David Lin, C J [NATIONAL CHIAO-TUNG UNIV; Matsufuru, Hideo [KEK; Ohki, Hiroshi [KYOTO UNIV; Onogi, Tetsuya [KYOTO UNIV; Yamazaki, Takeshi [UNIV OF TSUKUBA
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.
Directory of Open Access Journals (Sweden)
Esra Tuğ
2007-01-01
Full Text Available Wilson Disease (WD is an autosomal recessive hereditary disease of human copper metabolism, which causes hepatic and neuropsychiatric diseases. Estimated prevalence is 1: 30.000. In WD, ATP7B gene located on chromosome 13 (13q14.3-q21.1, coding the protein for hepatic copper transport and, having an important role in copper metabolism has been affected. Clinical findings in WD are complex and, neurological symptoms such as tremor, disartria and psychiatric disorders, acute liver deficiency, chronic hepatit or cirrhosis may develop. For the last year, 27 years old female patient observed in other medical centre owing to benign positional vertigo applied to our department. Her sister and brother have been diagnosed as WD. No peripheral syptoms of hepatic disease or hepatosplenomegaly existed in our patient. Neurological examination was normal to except for positional tremor. Because our patient had rare clinical features for WD and bad prognosis, presented by us to emphasize necessity of the researched of the most frequent mutations seen in Turkiye.
String corrections to circular Wilson loop and anomalies
Cagnazzo, Alessandra; Medina-Rincon, Daniel; Zarembo, Konstantin
2018-02-01
We study string quantum corrections to the ratio of latitude and circular Wilson loops in N = 4 super-Yang-Mills theory at strong coupling. Conformal gauge for the corresponding minimal surface in AdS5 × S 5 is singular and we show that an IR anomaly associated with the divergence in the conformal factor removes previously reported discrepancy with the exact field-theory result. We also carefully check conformal anomaly cancellation and recalculate fluctuation determinants by directly evaluting phaseshifts for all the fluctuation modes.
AdS/QCD, LIight-Front Holography, and the Non-perturbative Running Coupling
Energy Technology Data Exchange (ETDEWEB)
Brodsky, Stanley J.; /SLAC; de Teramond, Guy; /Costa Rica U.; 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.
A non-perturbative approach to the Coleman-Weinberg mechanism in massless scalar QED
International Nuclear Information System (INIS)
Malbouisson, A.P.C.; Nogueira, F.S.; Svaiter, N.F.
1995-08-01
We rederived non-perturbatively the Coleman-Weinberg expression for the effective potential for massless scalar QED. Our result is not restricted to small values of the coupling constants. This shows that the Coleman-Weinberg result can be established beyond the range of perturbation theory. Also, we derive it in a manifestly renormalization group invariant way. It is shown that with the derivation given no Landau ghost singularity arises. The finite temperature case is discussed. (author). 13 refs
Segment-based Eyring-Wilson viscosity model for polymer solutions
International Nuclear Information System (INIS)
Sadeghi, Rahmat
2005-01-01
A theory-based model is presented for correlating viscosity of polymer solutions and is based on the segment-based Eyring mixture viscosity model as well as the segment-based Wilson model for describing deviations from ideality. The model has been applied to several polymer solutions and the results show that it is reliable both for correlation and prediction of the viscosity of polymer solutions at different molar masses and temperature of the polymer
Syndrome parkinsonien secondaire à une maladie de Wilson chez ...
African Journals Online (AJOL)
Nous apportons une observation d'un cas de la maladie de Wilson, révélé par un syndrome parkinsonien. Le diagnostic a reposé sur les troubles neuropsychiques, la présence de l'anneau cornéen de Kayser-Fleischer, et les troubles du métabolisme du cuivre. Le scanner cérébral était normal, et l'IRM cérébrale a montré ...
Corrections to the Banks-Casher relation with Wilson quarks
Necco, S
2013-01-01
The Banks-Casher relation links the spectral density of the Dirac operator with the existence of a chiral condensate and spontaneous breaking of chiral symmetry. This relation receives corrections from a finite value of the quark mass, a finite space-time volume and, if evaluated on a discrete lattice, from the finite value of the lattice spacing a. We present a status report of a determination of these corrections for Wilson quarks.
Nucleon form factors on the lattice with light dynamical fermions
International Nuclear Information System (INIS)
Goeckeler, M.; Haegler, P.; Horsley, R.
2007-09-01
The electromagnetic form factors provide important insight into the internal structure of the nucleon and continue to be of major interest for experiment and phenomenology. For an intermediate range of momenta the form factors can be calculated on the lattice. However, the reliability of the results is limited by systematic errors mostly due to the required extrapolation to physical quark masses. Chiral effective field theories predict a rather strong quark mass dependence in a range which was yet inaccessible for lattice simulations. We give an update on recent results from the QCDSF collaboration using gauge configurations with dynamical N f =2, non-perturbatively O(a)-improved Wilson fermions at pion masses as low as 350 MeV. (orig.)
Nucleon form factors on the lattice with light dynamical fermions
Energy Technology Data Exchange (ETDEWEB)
Goeckeler, M. [Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Haegler, P. [Technische Univ. Muenchen, Garching (Germany). Inst. fuer Theoretische Physik T39; Horsley, R. [Edinburgh Univ. (GB). School of Physics] (and others)
2007-09-15
The electromagnetic form factors provide important insight into the internal structure of the nucleon and continue to be of major interest for experiment and phenomenology. For an intermediate range of momenta the form factors can be calculated on the lattice. However, the reliability of the results is limited by systematic errors mostly due to the required extrapolation to physical quark masses. Chiral effective field theories predict a rather strong quark mass dependence in a range which was yet inaccessible for lattice simulations. We give an update on recent results from the QCDSF collaboration using gauge configurations with dynamical N{sub f}=2, non-perturbatively O(a)-improved Wilson fermions at pion masses as low as 350 MeV. (orig.)
Gravity duals of half-BPS Wilson loops
International Nuclear Information System (INIS)
D'Hoker, Eric; Estes, John; Gutperle, Michael
2007-01-01
We explicitly construct the fully back-reacted half-BPS solutions in Type IIB supergravity which are dual to Wilson loops with 16 supersymmetries in N = 4 super Yang-Mills. In a first part, we use the methods of a companion paper to derive the exact general solution of the half-BPS equations on the space AdS 2 x S 2 x S 4 x Σ, with isometry group SO(2, 1) x SO(3) x SO(5) in terms of two locally harmonic functions on a Riemann surface Σ with boundary. These solutions, generally, have varying dilaton and axion, and non-vanishing 3-form fluxes. In a second part, we impose regularity and topology conditions. These non-singular solutions may be parametrized by a genus g ≥ 0 hyperelliptic surface Σ, all of whose branch points lie on the real line. Each genus g solution has only a single asymptotic AdS 5 x S 5 region, but exhibits g homology 3-spheres, and an extra g homology 5-spheres, carrying respectively RR 3-form and RR 5-form charges. For genus 0, we recover AdS 5 x S 5 with 3 free parameters, while for genus g ≥ 1, the solution has 2g+5 free parameters. The genus 1 case is studied in detail. Numerical analysis is used to show that the solutions are regular throughout the g = 1 parameter space. Collapse of a branch cut on Σ subtending either a homology 3-sphere or a homology 5-sphere is non-singular and yields the genus g-1 solution. This behavior is precisely expected of a proper dual to a Wilson loop in gauge theory
One-loop Wilson loops and the particle-interface potential in AdS/dCFT
Directory of Open Access Journals (Sweden)
Marius de Leeuw
2017-05-01
Full Text Available We initiate the calculation of quantum corrections to Wilson loops in a class of four-dimensional defect conformal field theories with vacuum expectation values based on N=4 super Yang–Mills theory. Concretely, we consider an infinite straight Wilson line, obtaining explicit results for the one-loop correction to its expectation value in the large-N limit. This allows us to extract the particle-interface potential of the theory. In a further double-scaling limit, we compare our results to those of a previous calculation in the dual string-theory set-up consisting of a D5-D3 probe-brane system with flux, and we find perfect agreement.
Wilson's operator expansion: can it fail
International Nuclear Information System (INIS)
Novikov, V.A.; Shifman, M.A.; Vainshtein, A.I.; Zakharov, V.I.
1984-01-01
The status of poperator product expansion (OPE) in the presence of nonperturbative effects is duscussed within the framework of some simople models 4d Higgs model, 2d sigma-model and Schwinger model are considered. The general formulation of OPE is presented and it is demonstrated that there exists a consistent procedure allowing one to define unabiguously both coefficient functions and matrix elements of compositie operators. One of the key elements of the procedure is introduction of an auxiliary paramparameter, the normalization point μ. The two extremss considered are lambda phi 4 theory with no spontaneous breaking of the symmetry and O(N) sigma model in the limit N→infinity. In the former case there is only perturbative contribution to (phi 2 ) while in the latter case the perturbative pieces are suppressed by 1/N factors. Numerically QCD is much closer to the O(N) sigma model in the large N limit. Comments on specific features of QCD are presented
College Board Response to "Harvard Educational Review" Article by Santelices and Wilson
College Board, 2010
2010-01-01
This is the College Board's response to a research article by Drs. Maria Veronica Santelices and Mark Wilson in the Harvard Educational Review, entitled "Unfair Treatment? The Case of Freedle, the SAT, and the Standardization Approach to Differential Item Functioning" (see EJ930622).
International Nuclear Information System (INIS)
Anabitarte, M.; Bellini, M.; Madriz Aguilar, Jose Edgar
2010-01-01
We extend to 5D an approach of a 4D non-perturbative formalism to study scalar metric fluctuations of a 5D Riemann-flat de Sitter background metric. In contrast with the results obtained in 4D, the spectrum of cosmological scalar metric fluctuations during inflation can be scale invariant and the background inflaton field can take sub-Planckian values. (orig.)
Wilson Fermions and Axion Electrodynamics in Optical Lattices
International Nuclear Information System (INIS)
Bermudez, A.; Martin-Delgado, M. A.; Mazza, L.; Rizzi, M.; Goldman, N.; Lewenstein, M.
2010-01-01
We show that ultracold Fermi gases in optical superlattices can be used as quantum simulators of relativistic lattice fermions in 3+1 dimensions. By exploiting laser-assisted tunneling, we find an analogue of the so-called naive Dirac fermions, and thus provide a realization of the fermion doubling problem. Moreover, we show how to implement Wilson fermions, and discuss how their mass can be inverted by tuning the laser intensities. In this regime, our atomic gas corresponds to a phase of matter where Maxwell electrodynamics is replaced by axion electrodynamics: a 3D topological insulator.
Nonperturbative QCD corrections to electroweak observables
Energy Technology Data Exchange (ETDEWEB)
Renner, Dru B. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Feng, Xu [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki (Japan); Jansen, Karl [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Petschlies, Marcus [The Cyprus Institute, Nicosia (Cyprus)
2012-06-15
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, effective field theory techniques 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 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 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 mention applications to the Adler function, which can be used to determine the strong coupling constant, and QCD corrections to muonic-hydrogen.
Nonperturbative production of multiboson states and quantum bubbles
International Nuclear Information System (INIS)
Gorsky, A.S.; Voloshin, M.B.
1993-01-01
The amplitude of production of n on-mass-shell scalar bosons by a highly virtual field φ is considered in a λφ 4 theory with weak coupling λ and spontaneously broken symmetry. The amplitude of this process is known to have an n exclamation point growth when the produced bosons are exactly at rest. Here it is shown that for n much-gt 1/λ the process goes through ''quantum bubbles,'' i.e., quantized droplets of a different vacuum phase, which are nonperturbative resonant states of the field φ. The bubbles provide a form factor for the production amplitude, which rapidly decreases above the threshold. As a result the probability of the process may be heavily suppressed and may decrease with energy E as exp(-constxE a ), where the power a depends on the number of space dimensions. Also discussed are the quantized states of bubbles and the amplitudes of their formation and decay
Infrared singularities of fermion propagator and their connection with the Wilson loop
International Nuclear Information System (INIS)
Sissakyan, A.N.; Skachkov, N.B.; Shevchenko, O.Yu.
1987-01-01
The factorization of infrared singularities of gauge-invariant spinor propagator is proved in the framework of QED. It turns out that this infrared factor coincides with the Wilson loop and accumulates all the dependence on the form of the path of the initial Green function
The Development of Field Guides for Birding: Gwillim, Wilson, Audubon and Peterson.
Cameron, Teddy
2000-01-01
Discusses the increasing interest of the public in nature and art of the 18th and 19th centuries, and making watercolor painting a part of the curriculum. Focuses on the works and publishing of Gwillim, Wilson, Audubon, and Peterson. (Contains 12 references.) (YDS)
International Nuclear Information System (INIS)
Oe, Shinji; Miyagawa, Koichiro; Honma, Yuichi; Harada, Masaru
2016-01-01
Copper is an essential trace element, however, excess copper is harmful to human health. Excess copper-derived oxidants contribute to the progression of Wilson disease, and oxidative stress induces accumulation of abnormal proteins. It is known that the endoplasmic reticulum (ER) plays an important role in proper protein folding, and that accumulation of misfolded proteins disturbs ER homeostasis resulting in ER stress. However, copper-induced ER homeostasis disturbance has not been fully clarified. We treated human hepatoma cell line (Huh7) and immortalized-human hepatocyte cell line (OUMS29) with copper and chemical chaperones, including 4-phenylbutyrate and ursodeoxycholic acid. We examined copper-induced oxidative stress, ER stress and apoptosis by immunofluorescence microscopy and immunoblot analyses. Furthermore, we examined the effects of copper on carcinogenesis. Excess copper induced not only oxidative stress but also ER stress. Furthermore, excess copper induced DNA damage and reduced cell proliferation. Chemical chaperones reduced this copper-induced hepatotoxicity. Excess copper induced hepatotoxicity via ER stress. We also confirmed the abnormality of ultra-structure of the ER of hepatocytes in patients with Wilson disease. These findings show that ER stress plays a pivotal role in Wilson disease, and suggests that chemical chaperones may have beneficial effects in the treatment of Wilson disease.
Energy Technology Data Exchange (ETDEWEB)
Oe, Shinji, E-mail: ooes@med.uoeh-u.ac.jp; Miyagawa, Koichiro, E-mail: koichiro@med.uoeh-u.ac.jp; Honma, Yuichi, E-mail: y-homma@med.uoeh-u.ac.jp; Harada, Masaru, E-mail: msrharada@med.uoeh-u.ac.jp
2016-09-10
Copper is an essential trace element, however, excess copper is harmful to human health. Excess copper-derived oxidants contribute to the progression of Wilson disease, and oxidative stress induces accumulation of abnormal proteins. It is known that the endoplasmic reticulum (ER) plays an important role in proper protein folding, and that accumulation of misfolded proteins disturbs ER homeostasis resulting in ER stress. However, copper-induced ER homeostasis disturbance has not been fully clarified. We treated human hepatoma cell line (Huh7) and immortalized-human hepatocyte cell line (OUMS29) with copper and chemical chaperones, including 4-phenylbutyrate and ursodeoxycholic acid. We examined copper-induced oxidative stress, ER stress and apoptosis by immunofluorescence microscopy and immunoblot analyses. Furthermore, we examined the effects of copper on carcinogenesis. Excess copper induced not only oxidative stress but also ER stress. Furthermore, excess copper induced DNA damage and reduced cell proliferation. Chemical chaperones reduced this copper-induced hepatotoxicity. Excess copper induced hepatotoxicity via ER stress. We also confirmed the abnormality of ultra-structure of the ER of hepatocytes in patients with Wilson disease. These findings show that ER stress plays a pivotal role in Wilson disease, and suggests that chemical chaperones may have beneficial effects in the treatment of Wilson disease.
New Results in {mathcal {N}}=2 N = 2 Theories from Non-perturbative String
Bonelli, Giulio; Grassi, Alba; Tanzini, Alessandro
2018-03-01
We describe the magnetic phase of SU(N) $\\mathcal{N}=2$ Super Yang-Mills theories in the self-dual Omega background in terms of a new class of multi-cut matrix models. These arise from a non-perturbative completion of topological strings in the dual four dimensional limit which engineers the gauge theory in the strongly coupled magnetic frame. The corresponding spectral determinants provide natural candidates for the tau functions of isomonodromy problems for flat spectral connections associated to the Seiberg-Witten geometry.
Biopolymer strategy for the treatment of Wilson´s disease
Czech Academy of Sciences Publication Activity Database
Vetrík, Miroslav; Mattová, J.; Macková, Hana; Kučka, Jan; Poučková, P.; Kukačková, Olivia; Brus, Jiří; Eigner-Henke, S.; Sedláček, Ondřej; Šefc, L.; Štěpánek, Petr; Hrubý, Martin
2018-01-01
Roč. 273, 10 March (2018), s. 131-138 ISSN 0168-3659 R&D Projects: GA ČR(CZ) GA16-02870S; GA MZd(CZ) NV15-25781A; GA MŠk(CZ) LM2015064; GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 Keywords : Wilson's disease * copper chelators * biopolymers Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 7.786, year: 2016
Comparative analysis of nonperturbative effects in B→Xulνl decays
International Nuclear Information System (INIS)
Kniehl, Bernd A.; Kramer, Gustav; Yang Jifeng
2007-01-01
In order to extract the Cabibbo-Kobayashi-Maskawa matrix element |V ub | from B→X u lν l decays, the overwhelming background from B→X c lν l decays must be reduced by appropriate acceptance cuts. We study the nonperturbative effects due to the motion of the b quark inside the B meson on the phenomenologically relevant decay distributions of B→X u lν l in the presence of such cuts in a comparative analysis based on shape functions and the parton model in the light cone limit. Comparisons with recent data from the CLEO, BABAR, and BELLE collaborations favor the shape-function approach
Standard model Wilson coefficients for c → ul{sup +}l{sup -} transitions at next-to-leading order
Energy Technology Data Exchange (ETDEWEB)
Boer, Stefan de [TU Dortmund (Germany); Mueller, Bastian; Seidel, Dirk [Uni Siegen (Germany)
2016-07-01
The standard theoretical framework to deal with exclusive, weak decays of heavy mesons is the so-called weak effective Hamiltonian. It involves the short-distance Wilson coefficients, which depend on the renormalization scale μ. For specific calculations one has to evolve the Wilson coefficients down from the electroweak scale μ{sub W} to the typical mass scale of the decay under consideration. This is done by solving a renormalization group equation for the effective operator basis. In this talk the results of a consistent two-step running of the c → ul{sup +}l{sup -} Wilson coefficients are presented. This running involves the intermediate scale μ{sub b} (with μ{sub W} > μ{sub b} > μ{sub c}) where the bottom quark is integrated out. All the matching coefficients and anomalous dimensions are taken to the required order by generalizing and extending results from b → s or s → d transitions available in the literature.
ABJM Wilson loops in arbitrary representations
Energy Technology Data Exchange (ETDEWEB)
Hatsuda, Yasuyuki [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Theory Group; Tokyo Institute of Technology (Japan). Dept. of Physics; Honda, Masazumi [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki (Japan); Moriyama, Sanefumi [Nagoya Univ. (Japan). Kobayashi Maskawa Inst. and Graduate School of Mathematics; Okuyama, Kazumi [Shinshu Univ., Matsumoto, Nagano (Japan). Dept. of Physics
2013-06-15
We study vacuum expectation values (VEVs) of circular half BPS Wilson loops in arbitrary representations in ABJM theory. We find that those in hook representations are reduced to elementary integrations thanks to the Fermi gas formalism, which are accessible from the numerical studies similar to the partition function in the previous studies. For non-hook representations, we show that the VEVs in the grand canonical formalism can be exactly expressed as determinants of those in the hook representations. Using these facts, we can study the instanton effects of the VEVs in various representations. Our results are consistent with the worldsheet instanton effects studied from the topological string and a prescription to include the membrane instanton effects by shifting the chemical potential, which has been successful for the partition function.
ABJM Wilson loops in arbitrary representations
International Nuclear Information System (INIS)
Hatsuda, Yasuyuki; Moriyama, Sanefumi; Okuyama, Kazumi
2013-06-01
We study vacuum expectation values (VEVs) of circular half BPS Wilson loops in arbitrary representations in ABJM theory. We find that those in hook representations are reduced to elementary integrations thanks to the Fermi gas formalism, which are accessible from the numerical studies similar to the partition function in the previous studies. For non-hook representations, we show that the VEVs in the grand canonical formalism can be exactly expressed as determinants of those in the hook representations. Using these facts, we can study the instanton effects of the VEVs in various representations. Our results are consistent with the worldsheet instanton effects studied from the topological string and a prescription to include the membrane instanton effects by shifting the chemical potential, which has been successful for the partition function.
Wilson loops in minimal surfaces
International Nuclear Information System (INIS)
Drukker, Nadav; Gross, David J.; Ooguri, Hirosi
1999-01-01
The AdS/CFT correspondence suggests that the Wilson loop of the large N gauge theory with N = 4 supersymmetry in 4 dimensions is described by a minimal surface in AdS 5 x S 5 . The authors examine various aspects of this proposal, comparing gauge theory expectations with computations of minimal surfaces. There is a distinguished class of loops, which the authors call BPS loops, whose expectation values are free from ultra-violet divergence. They formulate the loop equation for such loops. To the extent that they have checked, the minimal surface in AdS 5 x S 5 gives a solution of the equation. The authors also discuss the zig-zag symmetry of the loop operator. In the N = 4 gauge theory, they expect the zig-zag symmetry to hold when the loop does not couple the scalar fields in the supermultiplet. They will show how this is realized for the minimal surface
Wilson loops and minimal surfaces
International Nuclear Information System (INIS)
Drukker, Nadav; Gross, David J.; Ooguri, Hirosi
1999-01-01
The AdS-CFT correspondence suggests that the Wilson loop of the large N gauge theory with N=4 supersymmetry in four dimensions is described by a minimal surface in AdS 5 xS 5 . We examine various aspects of this proposal, comparing gauge theory expectations with computations of minimal surfaces. There is a distinguished class of loops, which we call BPS loops, whose expectation values are free from ultraviolet divergence. We formulate the loop equation for such loops. To the extent that we have checked, the minimal surface in AdS 5 xS 5 gives a solution of the equation. We also discuss the zigzag symmetry of the loop operator. In the N=4 gauge theory, we expect the zigzag symmetry to hold when the loop does not couple the scalar fields in the supermultiplet. We will show how this is realized for the minimal surface. (c) 1999 The American Physical Society
New results on the 3-loop heavy flavor Wilson coefficients in deep-inelastic scattering
Energy Technology Data Exchange (ETDEWEB)
Ablinger, Jakob; Schneider, Carsten [Johannes Kepler Univ., Linz (Austria). Research Inst. for Symbolic Computation; Bluemlein, Johannes; Freitas, Abilio de; Wissbrock, Fabian [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Hasselhuhn, Alexander [Johannes Kepler Univ., Linz (Austria). Research Inst. for Symbolic Computation; Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Klein, Sebastian [RWTH Aachen Univ. (Germany). Inst. fuer Theoretische Physik E
2013-01-02
We report on recent results obtained for the 3-loop heavy flavor Wilson coefficients in deepinelastic scattering (DIS) at general values of the Mellin variable N at larger scales of Q{sup 2}. These concern contributions to the gluonic ladder-topologies, the transition matrix elements in the variable flavor scheme of O(n{sub f}T{sup 2}{sub F}) and O(T{sup 2}{sub F}), and first results on higher 3-loop topologies. The knowledge of the heavy flavor Wilson coefficients at 3-loop order is of importance to extract the parton distribution functions and {alpha}{sub s}(M{sup 2}{sub Z}) in complete NNLO QCD analyses of the world precision data on the structure function F{sub 2}(x,Q{sup 2}).
BPS Wilson loops and Bremsstrahlung function in ABJ(M): a two loop analysis
Energy Technology Data Exchange (ETDEWEB)
Bianchi, Marco S. [Institut für Physik, Humboldt-Universität zu Berlin,Newtonstraße 15, 12489 Berlin (Germany); Griguolo, Luca [Dipartimento di Fisica e Scienze della Terra, Università di Parmaand INFN Gruppo Collegato di Parma,Viale G.P. Usberti 7/A, 43100 Parma (Italy); Leoni, Matias [Physics Department, FCEyN-UBA & IFIBA-CONICETCiudad Universitaria, Pabellón I, 1428, Buenos Aires (Argentina); Penati, Silvia [Dipartimento di Fisica, Università di Milano-Bicoccaand INFN, Sezione di Milano-Bicocca,Piazza della Scienza 3, I-20126 Milano (Italy); Seminara, Domenico [Dipartimento di Fisica, Università di Firenzeand INFN Sezione di Firenze,via G. Sansone 1, 50019 Sesto Fiorentino (Italy)
2014-06-19
We study a family of circular BPS Wilson loops in N=6 super Chern-Simons-matter theories, generalizing the usual 1/2-BPS circle. The scalar and fermionic couplings depend on two deformation parameters and these operators can be considered as the ABJ(M) counterpart of the DGRT latitudes defined in N=4 SYM. We perform a complete two-loop analysis of their vacuum expectation value, discuss the appearance of framing-like phases and propose a general relation with cohomologically equivalent bosonic operators. We make an all-loop proposal for computing the Bremsstrahlung function associated to the 1/2-BPS cusp in terms of these generalized Wilson loops. When applied to our two-loop result it reproduces the known expression. Finally, we comment on the generalization of this proposal to the bosonic 1/6-BPS case.
Topological string theory, modularity and non-perturbative physics
Energy Technology Data Exchange (ETDEWEB)
Rauch, Marco
2011-09-15
In this thesis the holomorphic anomaly of correlators in topological string theory, matrix models and supersymmetric gauge theories is investigated. In the first part it is shown how the techniques of direct integration known from topological string theory can be used to solve the closed amplitudes of Hermitian multi-cut matrix models with polynomial potentials. In the case of the cubic matrix model, explicit expressions for the ring of non-holomorphic modular forms that are needed to express all closed matrix model amplitudes are given. This allows to integrate the holomorphic anomaly equation up to holomorphic modular terms that are fixed by the gap condition up to genus four. There is an one-dimensional submanifold of the moduli space in which the spectral curve becomes the Seiberg-Witten curve and the ring reduces to the non-holomorphic modular ring of the group {gamma}(2). On that submanifold, the gap conditions completely fix the holomorphic ambiguity and the model can be solved explicitly to very high genus. Using these results it is possible to make precision tests of the connection between the large order behavior of the 1/N expansion and non-perturbative effects due to instantons. Finally, it is argued that a full understanding of the large genus asymptotics in the multi-cut case requires a new class of non-perturbative sectors in the matrix model. In the second part a holomorphic anomaly equation for the modified elliptic genus of two M5-branes wrapping a rigid divisor inside a Calabi-Yau manifold is derived using wall-crossing formulae and the theory of mock modular forms. The anomaly originates from restoring modularity of an indefinite theta-function capturing the wall-crossing of BPS invariants associated to D4- D2-D0 brane systems. The compatibility of this equation with anomaly equations previously observed in the context of N=4 topological Yang-Mills theory on P{sup 2} and E-strings obtained from wrapping M5-branes on a del Pezzo surface which in
Topological string theory, modularity and non-perturbative physics
International Nuclear Information System (INIS)
Rauch, Marco
2011-09-01
In this thesis the holomorphic anomaly of correlators in topological string theory, matrix models and supersymmetric gauge theories is investigated. In the first part it is shown how the techniques of direct integration known from topological string theory can be used to solve the closed amplitudes of Hermitian multi-cut matrix models with polynomial potentials. In the case of the cubic matrix model, explicit expressions for the ring of non-holomorphic modular forms that are needed to express all closed matrix model amplitudes are given. This allows to integrate the holomorphic anomaly equation up to holomorphic modular terms that are fixed by the gap condition up to genus four. There is an one-dimensional submanifold of the moduli space in which the spectral curve becomes the Seiberg-Witten curve and the ring reduces to the non-holomorphic modular ring of the group Γ(2). On that submanifold, the gap conditions completely fix the holomorphic ambiguity and the model can be solved explicitly to very high genus. Using these results it is possible to make precision tests of the connection between the large order behavior of the 1/N expansion and non-perturbative effects due to instantons. Finally, it is argued that a full understanding of the large genus asymptotics in the multi-cut case requires a new class of non-perturbative sectors in the matrix model. In the second part a holomorphic anomaly equation for the modified elliptic genus of two M5-branes wrapping a rigid divisor inside a Calabi-Yau manifold is derived using wall-crossing formulae and the theory of mock modular forms. The anomaly originates from restoring modularity of an indefinite theta-function capturing the wall-crossing of BPS invariants associated to D4- D2-D0 brane systems. The compatibility of this equation with anomaly equations previously observed in the context of N=4 topological Yang-Mills theory on P 2 and E-strings obtained from wrapping M5-branes on a del Pezzo surface which in turn is
Influence of cusps and intersections on the Wilson loop in ν-dimensional space
International Nuclear Information System (INIS)
Bezerra, V.B.
1984-01-01
A discussion is given about the influence of cusps and intersections on the calculation of the Wilson loop in ν-dimensional space. In particular, for the two-dimensional case, it is shown that there are no divergences. (Author) [pt
Energy Technology Data Exchange (ETDEWEB)
Walter, M.G.A.
2004-02-01
We consider several examples of a special class of heterotic compactifications, i.e. heterotic E{sub 8} x E{sub 8} orbifolds with Wilson line backgrounds. By developing a local perspective we show that a brane world like picture emerges. As an important result we prove that the local massless spectrum at such a brane can always be traced back to the global spectrum of a (different) orbifold without Wilson lines. One particular implication of this result is that the use of (discrete) Wilson lines for the construction of phenomenologically interesting models has to be rethought. We show that stringy constraints render the brane spectra consistent. Using our local picture we are able to compute the local anomalies appearing at the different branes for our examples and show that they can all be cancelled by a local version of the Green-Schwarz mechanism at the same time. (orig.)
Wilson Dslash Kernel From Lattice QCD Optimization
Energy Technology Data Exchange (ETDEWEB)
Joo, Balint [Jefferson Lab, Newport News, VA; Smelyanskiy, Mikhail [Parallel Computing Lab, Intel Corporation, California, USA; Kalamkar, Dhiraj D. [Parallel Computing Lab, Intel Corporation, India; Vaidyanathan, Karthikeyan [Parallel Computing Lab, Intel Corporation, India
2015-07-01
Lattice Quantum Chromodynamics (LQCD) is a numerical technique used for calculations in Theoretical Nuclear and High Energy Physics. LQCD is traditionally one of the first applications ported to many new high performance computing architectures and indeed LQCD practitioners have been known to design and build custom LQCD computers. Lattice QCD kernels are frequently used as benchmarks (e.g. 168.wupwise in the SPEC suite) and are generally well understood, and as such are ideal to illustrate several optimization techniques. In this chapter we will detail our work in optimizing the Wilson-Dslash kernels for Intel Xeon Phi, however, as we will show the technique gives excellent performance on regular Xeon Architecture as well.
Non-perturbative string theories and singular surfaces
International Nuclear Information System (INIS)
Bochicchio, M.
1990-01-01
Singular surfaces are shown to be dense in the Teichmueller space of all Riemann surfaces and in the grasmannian. This happens because a regular surface of genus h, obtained identifying 2h disks in pairs, can be approximated by a very large genus singular surface with punctures dense in the 2h disks. A scale ε is introduced and the approximate genus is defined as half the number of connected regions covered by punctures of radius ε. The non-perturbative partition function is proposed to be a scaling limit of the partition function on such infinite genus singular surfaces with a weight which is the coupling constant g raised to the approximate genus. For a gaussian model in any space-time dimension the regularized partition function on singular surfaces of infinite genus is the partition function of a two-dimensional lattice gas of charges and monopoles. It is shown that modular invariance of the partition function implies a version of the Dirac quantization condition for the values of the e/m charges. Before the scaling limit the phases of the lattice gas may be classified according to the 't Hooft criteria for the condensation of e/m operators. (orig.)
Nonperturbative Renormalization Group Approach to Polymerized Membranes
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.
Dual conformal transformations of smooth holographic Wilson loops
Energy Technology Data Exchange (ETDEWEB)
Dekel, Amit [Nordita, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, SE-106 91 Stockholm (Sweden)
2017-01-19
We study dual conformal transformations of minimal area surfaces in AdS{sub 5}×S{sup 5} corresponding to holographic smooth Wilson loops and some other related observables. To act with dual conformal transformations we map the string solutions to the dual space by means of T-duality, then we apply a conformal transformation and finally T-dualize back to the original space. The transformation maps between string solutions with different boundary contours. The boundary contours of the minimal surfaces are not mapped back to the AdS boundary, and the regularized area of the surface changes.
Lattice QCD at finite temperature with Wilson fermions
International Nuclear Information System (INIS)
Pinke, Christopher
2014-01-01
The subatomic world is governed by the strong interactions of quarks and gluons, described by Quantum Chromodynamics (QCD). Quarks experience confinement into colour-less objects, i.e. they can not be observed as free particles. Under extreme conditions such as high temperature or high density, this constraint softens and a transition to a phase where quarks and gluons are quasi-free particles (Quark-Gluon-Plasma) can occur. This environment resembles the conditions prevailing during the early stages of the universe shortly after the Big Bang. The phase diagram of QCD is under investigation in current and future collider experiments, for example at the Large Hadron Collider (LHC) or at the Facility for Antiproton and Ion Research (FAIR). Due to the strength of the strong interactions in the energy regime of interest, analytic methods can not be applied rigorously. The only tool to study QCD from first principles is given by simulations of its discretised version, Lattice QCD (LQCD). These simulations are in the high-performance computing area, hence, the numerical aspects of LQCD are a vital part in this field of research. In recent years, Graphic Processing Units (GPUs) have been incorporated in these simulations as they are a standard tool for general purpose calculations today. In the course of this thesis, the LQCD application CL 2 QCD has been developed, which allows for simulations on GPUs as well as on traditional CPUs, as it is based on OpenCL. CL 2 QCD constitutes the first application for Wilson type fermions in OpenCL. It provides excellent performance and has been applied in physics studies presented in this thesis. The investigation of the QCD phase diagram is hampered by the notorious sign-problem, which restricts current simulation algorithms to small values of the chemical potential. Theoretically, studying unphysical parameter ranges allows for constraints on the phase diagram. Of utmost importance is the clarification of the order of the finite
Wilson loops in the Higgs phase of large N field theories on the conifold
International Nuclear Information System (INIS)
Caceres, E.; Hernandez, R.
2000-04-01
We study the quark-antiquark interaction in the large N limit of the superconformal field theory on D-3branes at a Calabi-Yau conical singularity. We compute the Wilson loop in the AdS 5 x T 11 supergravity background for the SU(2N) x SU(2N) theory. We also calculate the Wilson loop for the Higgs phase where the gauge group is broken to SU(N) x SU(N) x SU D (N). This corresponds to a two center configuration with some of the branes at the singularity and the rest of them at a smooth point. The calculation exhibits the expected Coulomb dependence for the interaction. The angular distribution of the BPS states is different than the one for a spherical horizon. (author)
Potential of radiocopper in the diagnosis of Wilson disease
International Nuclear Information System (INIS)
Archambaud, F.; Yvart, J.; Moati, F.; Bernard, O.; Dommergues, J.P.; Desgrez, A.; Odievre, M.
1988-01-01
The purpose of the study is to establish if a simple test with 64 Cu is a valuable means of differenciating homozygotes for the ''Wilson's disease gene'' from heterozygous carriers and normal subjects for copper metabolism. A group of 73 subjects were studied. The only parameter which appears to be interesting is the percentage of administrated 64 Cu incorporated into ceruloplasmin at 48h. This test appears to be interesting to predict the disease and to avoid biopsy for determination of hepatic copper concentration [fr
Takemoto, Ricardo Massato; Universidade Estadual de Matingá; Luque, José Luis; UFRRJ; Luque, José Luis; UFRRJ
2008-01-01
Four species of caligid copepods, parasites of Oligoplites palometa (Cuvier, 1833), O. saurus (Bloch & Schneider, 1801) and O. saliens (Bloch, 1793) (Osteichthyes: Carangidae) from the Sepetiba Bay, coast of the state of Rio de Janeiro, Brazil, are presented. New geographical and host records for Caligus robustus Bassett-Smith, 1898, C. rufimaculatus Wilson, 1905, C. bonito Wilson, 1905 and Metacaligus rufus (Wilson, 1908) are given. Caligus oligoplitisi Carvalho, 1954 is considered a new jun...
Miller, W., Jr.; Li, Q.
2015-04-01
The Wilson and Racah polynomials can be characterized as basis functions for irreducible representations of the quadratic symmetry algebra of the quantum superintegrable system on the 2-sphere, HΨ = EΨ, with generic 3-parameter potential. Clearly, the polynomials are expansion coefficients for one eigenbasis of a symmetry operator L2 of H in terms of an eigenbasis of another symmetry operator L1, but the exact relationship appears not to have been made explicit. We work out the details of the expansion to show, explicitly, how the polynomials arise and how the principal properties of these functions: the measure, 3-term recurrence relation, 2nd order difference equation, duality of these relations, permutation symmetry, intertwining operators and an alternate derivation of Wilson functions - follow from the symmetry of this quantum system. This paper is an exercise to show that quantum mechancal concepts and recurrence relations for Gausian hypergeometrc functions alone suffice to explain these properties; we make no assumptions about the structure of Wilson polynomial/functions, but derive them from quantum principles. There is active interest in the relation between multivariable Wilson polynomials and the quantum superintegrable system on the n-sphere with generic potential, and these results should aid in the generalization. Contracting function space realizations of irreducible representations of this quadratic algebra to the other superintegrable systems one can obtain the full Askey scheme of orthogonal hypergeometric polynomials. All of these contractions of superintegrable systems with potential are uniquely induced by Wigner Lie algebra contractions of so(3, C) and e(2,C). All of the polynomials produced are interpretable as quantum expansion coefficients. It is important to extend this process to higher dimensions.
International Nuclear Information System (INIS)
Miller, W Jr; Li, Q
2015-01-01
The Wilson and Racah polynomials can be characterized as basis functions for irreducible representations of the quadratic symmetry algebra of the quantum superintegrable system on the 2-sphere, HΨ = EΨ, with generic 3-parameter potential. Clearly, the polynomials are expansion coefficients for one eigenbasis of a symmetry operator L 2 of H in terms of an eigenbasis of another symmetry operator L 1 , but the exact relationship appears not to have been made explicit. We work out the details of the expansion to show, explicitly, how the polynomials arise and how the principal properties of these functions: the measure, 3-term recurrence relation, 2nd order difference equation, duality of these relations, permutation symmetry, intertwining operators and an alternate derivation of Wilson functions - follow from the symmetry of this quantum system. This paper is an exercise to show that quantum mechancal concepts and recurrence relations for Gausian hypergeometrc functions alone suffice to explain these properties; we make no assumptions about the structure of Wilson polynomial/functions, but derive them from quantum principles. There is active interest in the relation between multivariable Wilson polynomials and the quantum superintegrable system on the n-sphere with generic potential, and these results should aid in the generalization. Contracting function space realizations of irreducible representations of this quadratic algebra to the other superintegrable systems one can obtain the full Askey scheme of orthogonal hypergeometric polynomials. All of these contractions of superintegrable systems with potential are uniquely induced by Wigner Lie algebra contractions of so(3, C) and e(2,C). All of the polynomials produced are interpretable as quantum expansion coefficients. It is important to extend this process to higher dimensions. (paper)
Insights into Wilson's Warbler migration from analyses of hydrogen stable-isotope ratios
Jeffrey F. Kelly; Viorel Atudorei; Zachary D. Sharp; Deborah M. Finch
2002-01-01
Our ability to link the breeding locations of individual passerines to migration stopover sites and wintering locations is limited. Stable isotopes of hydrogen contained in bird feathers have recently shown potential in this regard. We measured hydrogen stable-isotope ratios (deltaD) of feathers from breeding, migrating, and wintering Wilson's Warblers. Analyses...
Nonperturbative calculation of the shear viscosity in hot $\\phi^{4}$ theory in real time
Wang, E; Wang, Enke; Heinz, Ulrich
1999-01-01
Starting from the Kubo formula we calculate the shear viscosity in hot phi**4 theory nonperturbatively by resumming ladders with a real-time version of the Bethe-Salpeter equation at finite temperature. In the weak coupling limit, the generalized Fluctuation-Dissipation Theorem is shown to decouple the Bethe-Salpeter equations for the different real-time components of the 4-point function. The resulting scalar integral equation is identical with the one obtained by Jeon using diagrammatic ``cutting rules'' in the Imaginary Time Formalism.
Nonperturbative Quantum Physics from Low-Order Perturbation Theory.
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.
Nonperturbative Renormalization of Composite Operators with Overlap Fermions
Energy Technology Data Exchange (ETDEWEB)
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.
ESO Telescope Designer Raymond Wilson Wins Prestigious Kavli Award for Astrophysics
2010-06-01
Raymond Wilson, whose pioneering optics research at ESO made today's giant telescopes possible thanks to "active optics" technology, has been awarded the 2010 Kavli Prize in astrophysics. The founder and original leader of the Optics and Telescopes Group at ESO, Wilson shares the million-dollar prize with two American scientists, Jerry Nelson and Roger Angel. The biennial prize, presented by the Norwegian Academy of Science and Letters, the Kavli Foundation, and the Norwegian Ministry of Education and Research, was instituted in 2008 and is given to researchers who significantly advance knowledge in the fields of nanoscience, neuroscience, and astrophysics, acting as a complement to the Nobel Prize. The award is named for and funded by Fred Kavli, the Norwegian entrepreneur and philanthropist who later founded the Kavlico Corporation in the US - today one of the world's largest suppliers of sensors for aeronautic, automotive and industrial applications. Wilson, who joined ESO in 1972, strived to achieve optical perfection, developing the concept of active optics as a way to enhance the size of telescopic primary mirrors. It is the size of these mirrors that determines the ability of a telescope to gather light and study faint and distant objects. Before active optics, mirrors over six metres in diameter were impossible, being too heavy, costly, and likely to bend from gravity and temperature changes. The use of active optics, which preserves optimal image quality by continually adjusting the mirror's shape during observations, made lighter, thinner so-called "meniscus mirrors" possible. Wilson first led the implementation of active optics in the revolutionary New Technology Telescope at ESO's La Silla Observatory, and continued to develop and improve the technology until his retirement in 1993. Since then, active optics have become a standard part of modern astronomy, applied in every big telescope including ESO's Very Large Telescope (VLT), a telescope array
BK-parameter from Nf=2 twisted mass lattice QCD
International Nuclear Information System (INIS)
Constantinou, M.; Dimopoulos, P.; Frezzotti, R.; INFN, Rome
2011-01-01
We present an unquenched N f = 2 lattice computation of the B K parameter which controls K 0 - anti K 0 oscillations. A partially quenched setup is employed with two maximally twisted dynamical (sea) light Wilson quarks, and valence quarks of both the maximally twisted and the Osterwalder-Seiler variety. Suitable combinations of these two kinds of valence quarks lead to a lattice definition of the B K parameter which is both multiplicatively renormalizable and O(a) improved. Employing the non-perturbative RI-MOM scheme, in the continuum limit and at the physical value of the pion mass we get B RGI K =0.729±0.030, a number well in line with the existing quenched and unquenched determinations. (orig.)
Nucleon form factors. Probing the chiral limit
Energy Technology Data Exchange (ETDEWEB)
Goeckeler, M. [Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Haegler, P. [Technische Univ. Muenchen, Garching (Germany). Physik-Dept.; Horsley, R. [Edinburgh Univ. (GB). School of Physics] (and others)
2006-10-15
The electromagnetic form factors provide important hints for the internal structure of the nucleon and continue to be of major interest for experimentalists. For an intermediate range of momentum transfers the form factors can be calculated on the lattice. However, reliability of the results is limited by systematic errors due to the required extrapolation to physical quark masses. Chiral effective field theories predict a rather strong quark mass dependence in a range which was yet unaccessible for lattice simulations. We give an update on recent results from the QCDSF collaboration using gauge configurations with Nf=2, non-perturbatively O(a)-improved Wilson fermions at very small quark masses down to 340 MeV pion mass, where we start to probe the relevant quark mass region. (orig.)
B{sub K}-parameter from N{sub f}=2 twisted mass lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Constantinou, M. [Cyprus Univ., Nicosia (Cyprus). Dept. of Physics; Dimopoulos, P. [Roma Univ. (Italy). Dipt. di Fisica; Frezzotti, R. [Roma ' ' Tor Vergata' ' Univ. (Italy). Dipt. di Fisica; INFN, Rome (IT). Dipt. di Fisica] (and others)
2011-01-07
We present an unquenched N{sub f} = 2 lattice computation of the B{sub K} parameter which controls K{sup 0}- anti K{sup 0} oscillations. A partially quenched setup is employed with two maximally twisted dynamical (sea) light Wilson quarks, and valence quarks of both the maximally twisted and the Osterwalder-Seiler variety. Suitable combinations of these two kinds of valence quarks lead to a lattice definition of the B{sub K} parameter which is both multiplicatively renormalizable and O(a) improved. Employing the non-perturbative RI-MOM scheme, in the continuum limit and at the physical value of the pion mass we get B{sup RGI}{sub K}=0.729{+-}0.030, a number well in line with the existing quenched and unquenched determinations. (orig.)
Nucleon form factors. Probing the chiral limit
International Nuclear Information System (INIS)
Goeckeler, M.; Haegler, P.; Horsley, R.
2006-10-01
The electromagnetic form factors provide important hints for the internal structure of the nucleon and continue to be of major interest for experimentalists. For an intermediate range of momentum transfers the form factors can be calculated on the lattice. However, reliability of the results is limited by systematic errors due to the required extrapolation to physical quark masses. Chiral effective field theories predict a rather strong quark mass dependence in a range which was yet unaccessible for lattice simulations. We give an update on recent results from the QCDSF collaboration using gauge configurations with Nf=2, non-perturbatively O(a)-improved Wilson fermions at very small quark masses down to 340 MeV pion mass, where we start to probe the relevant quark mass region. (orig.)
Recursion relations for multi-gluon off-shell amplitudes on the light-front and Wilson lines
Directory of Open Access Journals (Sweden)
C. Cruz-Santiago
2015-06-01
Full Text Available We analyze the off-shell scattering amplitudes in the framework of the light-front perturbation theory. It is shown that the previously derived recursion relation between tree level off-shell amplitudes in this formalism actually resums whole classes of graphs into a Wilson line. More precisely, we establish a correspondence between the light-front methods for the computation of the off-shell amplitudes and the approach which makes use of the matrix elements of straight infinite Wilson lines, which are manifestly gauge invariant objects. Furthermore, since it is needed to explicitly verify the gauge invariance of light-front amplitudes, it is demonstrated that the Ward identities in this framework need additional instantaneous terms in the light-front graphs.
Adaptive Multigrid Algorithm for the Lattice Wilson-Dirac Operator
International Nuclear Information System (INIS)
Babich, R.; Brower, R. C.; Rebbi, C.; Brannick, J.; Clark, M. A.; Manteuffel, T. A.; McCormick, S. F.; Osborn, J. C.
2010-01-01
We present an adaptive multigrid solver for application to the non-Hermitian Wilson-Dirac system of QCD. The key components leading to the success of our proposed algorithm are the use of an adaptive projection onto coarse grids that preserves the near null space of the system matrix together with a simplified form of the correction based on the so-called γ 5 -Hermitian symmetry of the Dirac operator. We demonstrate that the algorithm nearly eliminates critical slowing down in the chiral limit and that it has weak dependence on the lattice volume.
Mowat-Wilson-syndrom hos tre danske børn
DEFF Research Database (Denmark)
Nissen, Karin Bækgaard; Søndergaard, Charlotte; Thelle, Thomas
2011-01-01
Mowat-Wilson syndrome (MWS) is an autosomal dominant intellectual disability syndrome characterised by unique facial features and congenital anomalies such as Hirschsprung disease, congenital heart defects, corpus callosum agenesis and urinary tract anomalies. Some cases also present epilepsy......, growth retardation and microcephaly. The syndrome is caused by mutations or deletions of the ZEB2 gene at chromosome 2q22-q23. MWS was first described in 1998 and until now approximately 180 cases have been reported worldwide. We report the first three molecularly confirmed Danish cases with MWS....
Critical behavior of the Schwinger model with Wilson fermions
International Nuclear Information System (INIS)
Azcoiti, V.; Laliena, V.
1995-09-01
A detailed analysis, in the framework of the MFA approach, of the critical behaviour of the lattice Schwinger model with Wilson fermions on lattices up to 24 2 , through the study of the Lee-Yang zeros and the specific heat, is presented. Compelling evidence is found for a critical line ending at k= 0.25 at large β. Finite size scaling analysis on lattices 8 2 , 12 2 , 16 2 , 20 2 and 24 2 indicates a continuous transition. The hyper scaling relation is verified in the explored β region
Supergravity couplings to Noncommutative Branes, Open Wilson Lines and Generalised Star Products
International Nuclear Information System (INIS)
Das, S.R.; Trivedi, S.P.
2001-01-01
Noncommutative gauge theories can be constructed from ordinary U(∞) gauge theories in lower dimensions. Using this construction we identify the operators on noncommutative D-branes which couple to linearized supergravity backgrounds, from a knowledge of such couplings to lower dimensional D-branes with no B field. These operators belong to a class of gauge invariant observables involving open Wilson lines. Assuming a DBI form of the coupling we show, to second order in the gauge potential but to all orders of the noncommutativity parameter, that our proposal agrees with the operator obtained in terms of ordinary gauge fields by considering brane actions in backgrounds and then using the Seiberg-Witten map to rewrite this in terms of noncommutative gauge fields. Our result clarify why a certain commutative but non-associative 'generalized star product' appears both in the expansion of the open Wilson line, as well as in string amplitude computations of open string-closed string couplings. We outline how our procedure can be used to obtain operators in the noncommutative theory which are holographically dual to supergravity modes. (author)
Non-perturbative scalar potential inspired by type IIA strings on rigid CY
Energy Technology Data Exchange (ETDEWEB)
Alexandrov, Sergei [Laboratoire Charles Coulomb (L2C), UMR 5221, CNRS-Université de Montpellier,F-34095, Montpellier (France); Ketov, Sergei V. [Department of Physics, Tokyo Metropolitan University,1-1 Minami-ohsawa, Hachioji-shi, Tokyo 192-0397 (Japan); Kavli Institute for the Physics and Mathematics of the Universe (IPMU), The University of Tokyo,Chiba 277-8568 (Japan); Institute of Physics and Technology, Tomsk Polytechnic University,30 Lenin Ave., Tomsk 634050 (Russian Federation); Wakimoto, Yuki [Department of Physics, Tokyo Metropolitan University,1-1 Minami-ohsawa, Hachioji-shi, Tokyo 192-0397 (Japan)
2016-11-10
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.