WorldWideScience

Sample records for nonequilibrium qft vertex

  1. Systematic approach to leptogenesis in nonequilibrium QFT: Vertex contribution to the CP-violating parameter

    Science.gov (United States)

    Garny, M.; Hohenegger, A.; Kartavtsev, A.; Lindner, M.

    2009-12-01

    The generation of a baryon asymmetry via leptogenesis is usually studied by means of classical kinetic equations whose applicability to processes in the hot and expanding early universe is questionable. The approximations implied by the state-of-the-art description can be tested in a first-principle approach based on nonequilibrium field theory techniques. Here, we apply the Schwinger-Keldysh/Kadanoff-Baym formalism to a simple toy model of leptogenesis. We find that, within the toy model, medium effects increase the vertex contribution to the CP-violating parameter. At high temperatures it is a few times larger than in vacuum and asymptotically reaches the vacuum value as the temperature decreases. Contrary to the results obtained earlier in the framework of thermal field theory, the corrections are only linear in the particle number densities. An important feature of the Kadanoff-Baym formalism is that it is free of the double-counting problem, i.e. no need for real intermediate state subtraction arises. In particular, this means that the structure of the equations automatically ensures that the asymmetry vanishes in equilibrium. These results give a first glimpse into a number of new and interesting effects that can be studied in the framework of nonequilibrium field theory.

  2. Accreting neutron stars by QFT

    Science.gov (United States)

    Chen, Shao-Guang

    I deduce the new gravitational formula from the variance in mass of QFT and GR (H05-0029-08, E15-0039 -08, E14-0032-08, D31-0054-10) in the partial differential: f (QFT) = f (GR) = delta∂ (m v)/delta∂ t = f _{P} + f _{C} , f _{P} = m delta∂ v / delta∂ t = - ( G m M /r (2) ) r / r, f _{C} = v delta∂ m / delta∂ t = - ( G mM / r (2) ) v / c (1). f (QFT) is the quasi-Casimir pressure of net virtual neutrinos nuν _{0} flux (after counteract contrary direction nuν _{0}). f (GR) is equivalent to Einstein’s equation as a new version of GR. GR can be inferred from Eq.(1) thereby from QFT, but QFT cannot be inferred from Eq.(1) or GR. f (QFT) is essential but f (GR) is phenomenological. Eq.(1) is obtained just by to absorb the essence of corpuscule collided gravitation origin ism proposed by Fatio in 1690 and 1920 Majorana’s experiment concept about gravitational shield effect again fuse with QFT. Its core content is that the gravity produced by particles collide cannot linear addition, i.e., Eq.(1) with the adding nonlinearity caused by the variable mass to replace the nonlinearity of Einstein’s equation. The nonlinear gravitation problems can be solved using the classical gradual approximation of alone f _{P} and alone f _{C}. Such as the calculation of advance of the perihelion of QFT, let the gravitational potential U = - G M /r which is just the distribution density of net nuν _{0} flux. From SR we again get Eq.(1): f (QFT) = f _{P} + f _{C}, f _{P} = - m ( delta∂ U / delta∂ r) r / r, f _{C} = - m ( delta∂U / delta∂ r) v / c , U = (1 - betaβ (2) )V, V is the Newtonian gravitational potential. f_{ P} correspond the change rate of three-dimensional momentum p, f_{C} correspond the change rate of fourth dimensional momentum i m c which show directly as a dissipative force of mass change. In my paper ‘To cross the great gap between the modern physics and classic physics, China Science &Technology Overview 129 85-91 (2011)’ with the

  3. Vertex detectors

    International Nuclear Information System (INIS)

    Lueth, V.

    1992-07-01

    The purpose of a vertex detector is to measure position and angles of charged particle tracks to sufficient precision so as to be able to separate tracks originating from decay vertices from those produced at the interaction vertex. Such measurements are interesting because they permit the detection of weakly decaying particles with lifetimes down to 10 -13 s, among them the τ lepton and charm and beauty hadrons. These two lectures are intended to introduce the reader to the different techniques for the detection of secondary vertices that have been developed over the past decades. The first lecture includes a brief introduction to the methods used to detect secondary vertices and to estimate particle lifetimes. It describes the traditional technologies, based on photographic recording in emulsions and on film of bubble chambers, and introduces fast electronic registration of signals derived from scintillating fibers, drift chambers and gaseous micro-strip chambers. The second lecture is devoted to solid state detectors. It begins with a brief introduction into semiconductor devices, and then describes the application of large arrays of strip and pixel diodes for charged particle tracking. These lectures can only serve as an introduction the topic of vertex detectors. Time and space do not allow for an in-depth coverage of many of the interesting aspects of vertex detector design and operation

  4. De Sitter vacua of strongly interacting QFT

    Energy Technology Data Exchange (ETDEWEB)

    Buchel, Alex [Department of Applied Mathematics, University of Western Ontario,London, Ontario N6A 5B7 (Canada); Department of Physics and Astronomy, University of Western Ontario,London, Ontario N6A 5B7 (Canada); Perimeter Institute for Theoretical Physics,Waterloo, Ontario N2J 2W9 (Canada); Karapetyan, Aleksandr [Department of Applied Mathematics, University of Western Ontario,London, Ontario N6A 5B7 (Canada)

    2017-03-22

    We use holographic correspondence to argue that Euclidean (Bunch-Davies) vacuum is a late-time attractor of the dynamical evolution of quantum gauge theories at strong coupling. The Bunch-Davies vacuum is not an adiabatic state, if the gauge theory is non-conformal — the comoving entropy production rate is nonzero. Using the N=2{sup ∗} gauge theory holography, we explore prospects of explaining current accelerated expansion of the Universe as due to the vacuum energy of a strongly coupled QFT.

  5. Aspects of Berry phase in QFT

    Energy Technology Data Exchange (ETDEWEB)

    Baggio, Marco [Institute for Theoretical Physics, KU Leuven,Celestijnenlaan 200D, B-3001 Leuven (Belgium); Niarchos, Vasilis [Department of Mathematical Sciences and Center for Particle Theory, Durham University,South Road, Durham, DH1 3LE (United Kingdom); Papadodimas, Kyriakos [Theory Group, Physics Department, CERN,CH-1211 Geneva 23 (Switzerland); Van Swinderen Institute for Particle Physics and Gravity, University of Groningen,Nijenborgh 4, 9747 AG Groningen (Netherlands)

    2017-04-11

    When continuous parameters in a QFT are varied adiabatically, quantum states typically undergo mixing — a phenomenon characterized by the Berry phase. We initiate a systematic analysis of the Berry phase in QFT using standard quantum mechanics methods. We show that a non-trivial Berry phase appears in many familiar QFTs. We study a variety of examples including free electromagnetism with a theta angle, and certain supersymmetric QFTs in two and four spacetime dimensions. We also argue that a large class of QFTs with rich Berry properties is provided by CFTs with non-trivial conformal manifolds. Using the operator-state correspondence we demonstrate in this case that the Berry connection is equivalent to the connection on the conformal manifold derived previously in conformal perturbation theory. In the special case of chiral primary states in 2d N=(2,2) and 4d N=2 SCFTs the Berry phase is governed by the tt{sup ∗} equations. We present a technically useful rederivation of these equations using quantum mechanics methods.

  6. Vertex Reconstruction in CMS

    CERN Document Server

    Chabanat, E; D'Hondt, J; Vanlaer, P; Prokofiev, K; Speer, T; Frühwirth, R; Waltenberger, W

    2005-01-01

    Because of the high track multiplicity in the final states expected in proton collisions at the LHC experiments, novel vertex reconstruction algorithms are required. The vertex reconstruction problem can be decomposed into a pattern recognition problem ("vertex finding") and an estimation problem ("vertex fitting"). Starting from least-square methods, ways to render the classical algorithms more robust are discussed and the statistical properties of the novel methods are shown. A whole set of different approaches for the vertex finding problem is presented and compared in relevant physics channels.

  7. Vertex reconstruction in CMS

    International Nuclear Information System (INIS)

    Chabanat, E.; D'Hondt, J.; Estre, N.; Fruehwirth, R.; Prokofiev, K.; Speer, T.; Vanlaer, P.; Waltenberger, W.

    2005-01-01

    Due to the high track multiplicity in the final states expected in proton collisions at the LHC experiments, novel vertex reconstruction algorithms are required. The vertex reconstruction problem can be decomposed into a pattern recognition problem ('vertex finding') and an estimation problem ('vertex fitting'). Starting from least-squares methods, robustifications of the classical algorithms are discussed and the statistical properties of the novel methods are shown. A whole set of different approaches for the vertex finding problem is presented and compared in relevant physics channels

  8. The refined topological vertex

    International Nuclear Information System (INIS)

    Iqbal, Amer; Kozcaz, Can; Vafa, Cumrun

    2009-01-01

    We define a refined topological vertex which depends in addition on a parameter, which physically corresponds to extending the self-dual graviphoton field strength to a more general configuration. Using this refined topological vertex we compute, using geometric engineering, a two-parameter (equivariant) instanton expansion of gauge theories which reproduce the results of Nekrasov. The refined vertex is also expected to be related to Khovanov knot invariants.

  9. Coupled Solar Wind-Magnetosphere-Ionosphere-Thermosphere System by QFT

    Science.gov (United States)

    Chen, Shao-Guang

    I deduce the new gravitational formula from the variance in mass of QFT and GR (H05-0029-08, E15-0039 -08, E14-0032-08, D31-0054-10) in the partial differential: f (QFT) = f (GR) = delta∂ (m v)/delta∂ t = f _{P} + f _{C} , f _{P} = m delta∂ v / delta∂ t = - ( G m M /r (2) ) r / r, f _{C} = v delta∂ m / delta∂ t = - ( G mM / r (2) ) v / c (1), f (QFT) is the quasi-Casimir pressure of net virtual neutrinos nuν _{0} flux (after counteract contrary direction nuν _{0}). f (GR) is equivalent to Einstein’s equation as a new version of GR. GR can be inferred from Eq.(1) thereby from QFT, but QFT cannot be inferred from Eq.(1) or GR. f (QFT) is essential but f (GR) is phenomenological. Eq.(1) is obtained just by to absorb the essence of corpuscule collided gravitation origin ism proposed by Fatio in 1690 and 1920 Majorana’s experiment concept about gravitational shield effect again fuse with QFT. Its core content is that the gravity produced by particles collide cannot linear addition, i.e., Eq.(1) with the adding nonlinearity caused by the variable mass to replace the nonlinearity of Einstein’s equation and the nonlinear gravitation problems can be solved using the classical gradual approximation of alone f _{P} and alone f _{C}. In my paper ‘To cross the great gap between the modern physics and classic physics, China Science &Technology Overview 129 85-91(2011)’ with the measuring value of one-way velocity of light (H05-0020-08) to replace the infinity value of light speed measured by Galileo in 1607, thereby the mass m in NM will become variable m. Or else, the energy of electron in accelerator should not larger than 0.51Mev which conflict with the experimental fact. According to the variable mass and the definition of force we again get Eq.(1) from NM without hypothesis, i.e., NM is generalized in which Galileo coordinates transformation and the action at a distance will be of no effect. Eq.(1) has more reliable experimental base and generalized

  10. Advance of the perihelion of Mercury deduced from QFT

    Science.gov (United States)

    Chen, Shao-Guang

    I deduce the new gravitational formula from the variance in mass of QFT and GR (H05-0029-08, E15-0039 -08, E14-0032-08, D31-0054-10) in the partial differential: f (QFT) = f (GR) = delta∂ (m v)/delta∂ t = f _{P} + f _{C} , f _{P} = m delta∂ v / delta∂ t = - ( G m M /r (2) ) r / r, f _{C} = v delta∂ m / delta∂ t = - ( G m M / r (2) ) v / c (1), f (QFT) is the quasi-Casimir pressure of net virtual neutrinos nuν _{0} flux (after counteract contrary direction nuν _{0}). f (GR) is equivalent to Einstein’s equation, Eq. (1) is a new version of GR and can be solved exactly. Its core content is that the gravity produced by particles collide cannot linear addition, i.e., the nonlinearity of Einstein equation had been replaced by the nonlinearity caused by the variable mass in Eq.(1). Einstein equation can be inferred from Eq.(1) thereby from QFT, but QFT cannot be inferred from Eq.(1) or GR. f (QFT) is essential but f (GR) is phenomenological. Eq.(1) is obtained just by to absorb the essence of corpuscule collided gravitation origin ism proposed by Fatio in 1690 and 1920 Majorana’s experiment concept about gravitational shield effect again fuse with QFT. In my paper ‘QFT’S advance of the perihelion of Mercury, China Science &Technology Overview 125 88-90 (2011)’ QFT gravitational potential U = - G M /r is just the distribution density of net nuν _{0} flux, from SR we again get that: f (QFT) = f _{P} + f _{C}, f _{P} = - m ( delta∂ U / delta∂ r) r / r, f _{C} = - m ( delta∂U / delta∂ r) v / c (2), f _{ P} correspond the change rate of three-dimensional momentum p, f _{C} correspond the change rate of fourth dimensional momentum i m c which show directly as a dissipative force of mass change. According to Eq.(2) the circular motion is instability and elliptic motion is in the auto-stability state. In the fluctuation vacuum a particle with mass M neighbor another particle with mass m, the renormalization mass M and m will be less than that when

  11. Vertex routing models

    International Nuclear Information System (INIS)

    Markovic, D; Gros, C

    2009-01-01

    A class of models describing the flow of information within networks via routing processes is proposed and investigated, concentrating on the effects of memory traces on the global properties. The long-term flow of information is governed by cyclic attractors, allowing to define a measure for the information centrality of a vertex given by the number of attractors passing through this vertex. We find the number of vertices having a nonzero information centrality to be extensive/subextensive for models with/without a memory trace in the thermodynamic limit. We evaluate the distribution of the number of cycles, of the cycle length and of the maximal basins of attraction, finding a complete scaling collapse in the thermodynamic limit for the latter. Possible implications of our results for the information flow in social networks are discussed.

  12. The ARGUS vertex trigger

    International Nuclear Information System (INIS)

    Koch, N.; Kolander, M.; Kolanoski, H.; Siegmund, T.; Bergter, J.; Eckstein, P.; Schubert, K.R.; Waldi, R.; Imhof, M.; Ressing, D.; Weiss, U.; Weseler, S.

    1995-09-01

    A fast second level trigger has been developed for the ARGUS experiment which recognizes tracks originating from the interaction region. The processor compares the hits in the ARGUS Micro Vertex Drift Chamber to 245760 masks stored in random access memories. The masks which are fully defined in three dimensions are able to reject tracks originating in the wall of the narrow beampipe of 10.5 mm radius. (orig.)

  13. Representing vertex-transitive Vertex-transitive graphs on Groupoids

    African Journals Online (AJOL)

    Vertex-transitive graphs are one of the most favoured class of graphs in modelling scientific phenomena if symmetry is at issue. An understanding of these graphs should, therefore, be an obvious undertaking. Here, we present a characterisation of vertex-transitive graphs as left loop graphs and expose the measure of ...

  14. The Belle Silicon Vertex Detector

    CERN Document Server

    Kawasaki, T

    2002-01-01

    The Belle Silicon Vertex Detector (SVD) started working from June 1999 at the KEK B-factory experiment. The main purpose of the SVD is to make precise measurements of the B decay vertex position, which are essential for the observation of CP asymmetries. Excellent vertex resolution and a good detection efficiency are required for the SVD. In the present paper, the performance of Belle SVD is reviewed. The upgrade plan for the SVD2, which is under construction and will be installed in summer 2002, is also presented.

  15. LCFI vertex detector design studies

    Energy Technology Data Exchange (ETDEWEB)

    Milstene, C.; Sopczak, A.

    2005-12-01

    A vertex detector concept of the Linear Collider Flavor Identification (LCFI) collaboration, which studies CCD detectors for quark flavor identification, has been implemented in simulations for c-quark tagging in scalar top studies. The production and decay of scalar top quarks (stops) is particularly interesting for the development of the vertex detector as only two c-quarks and missing energy (from undetected neutralinos) are produced for light stops. Previous studies investigated the vertex detector design in scenarios with large mass differences between stop and neutralino, corresponding to large visible energy in the detector. In this study we investigate the tagging performance dependence on the vertex detector design in a scenario with small visible energy for the International Linear Collider (ILC).

  16. Nonequilibrium molecular dynamics

    OpenAIRE

    Wm.G.Hoover; C.G.Hoover

    2005-01-01

    Nonequilibrium Molecular Dynamics is a powerful simulation tool. Like its equilibrium cousin, nonequilibrium molecular dynamics is based on time-reversible equations of motion. But unlike conventional mechanics, nonequilibrium molecular dynamics provides a consistent microscopic basis for the irreversible macroscopic Second Law of Thermodynamics. We recall here how fast computers led to the development of nonequilibrium molecular dynamics from the statistical mechanics of the 1950s. Computer-...

  17. QFT Based Robust Positioning Control of the PMSM Using Automatic Loop Shaping with Teaching Learning Optimization

    Directory of Open Access Journals (Sweden)

    Nitish Katal

    2016-01-01

    Full Text Available Automation of the robust control system synthesis for uncertain systems is of great practical interest. In this paper, the loop shaping step for synthesizing quantitative feedback theory (QFT based controller for a two-phase permanent magnet stepper motor (PMSM has been automated using teaching learning-based optimization (TLBO algorithm. The QFT controller design problem has been posed as an optimization problem and TLBO algorithm has been used to minimize the proposed cost function. This facilitates designing low-order fixed-structure controller, eliminates the need of manual loop shaping step on the Nichols charts, and prevents the overdesign of the controller. A performance comparison of the designed controller has been made with the classical PID tuning method of Ziegler-Nichols and QFT controller tuned using other optimization algorithms. The simulation results show that the designed QFT controller using TLBO offers robust stability, disturbance rejection, and proper reference tracking over a range of PMSM’s parametric uncertainties as compared to the classical design techniques.

  18. Non-standard perturbative methods for the effective potential in λφ4 QFT

    International Nuclear Information System (INIS)

    Okopinska, A.

    1986-07-01

    The effective potential in scalar QFT is calculated in the non-standard perturbative methods and compared with the conventional loop expansion. In the space time dimensions 0 and 1 the results are compared with the ''exact'' effective potential obtained numerically. In 4 dimensions we show that λφ 4 theory is non-interacting. (author)

  19. Aplicación de técnicas de control robusto QFT a sistemas navales

    Directory of Open Access Journals (Sweden)

    R. Muñoz-Mansilla

    2012-07-01

    Full Text Available Resumen: En este trabajo se realiza un análisis de diferentes metodologías de control robusto basadas en la técnica denominada Teoría de la Realimentación Cuantitativa, QFT (Quantitative Feedback Theory para resolver diferentes problemáticas que surgen en los sistemas de control marinos. En concreto se estudia el posicionamiento dinámico de una plataforma marina fondeada, la estabilización de un buque de alta velocidad, y el seguimiento de referencia para un aerodeslizador. Estos problemas de control presentan grandes retos de diseño, dado que son sistemas no lineales, multivariables, subactuados y con grandes perturbaciones. Los diferentes tipos de diseño QFT obtenidos consiguen una implementación robusta con prevención de acoplamientos, reducción de perturbaciones ambientales, respuestas rápidas y precisión en el seguimiento, que demuestran finalmente que es una alternativa práctica y eficaz para la solución de problemas de control en vehículos navales Abstract: In this work an analysis of the application of the Quantitative Feedback Theory (QFT technique to different marine systems is presented. Specifically, the problems of dynamic positioning of a moored platform, stabilization of a fast ferry and the tracking control of a hovercraft are studied. This control problem presents interesting questions to deal with, since the plants are non-linear, multivariable, underactuated and subject to large disturbances due to waves.Three multivariable nonlinear problems are solved using different sequential procedures. It is shown that the QFT controllers synthesis achieve robust performance, decoupling, environment disturbance reduction, quick answers and tracking precision. Therefore, it is shown that robust techniques based on QFT methodologies result feasible and very suitable, constituting an attractive alternative for robust design of marine vehicles. Palabras clave: Control robusto, sistema no lineal, vehículo subactuado

  20. Aleph silicon microstrip vertex detector

    CERN Multimedia

    Laurent Guiraud

    1998-01-01

    This microstrip vertex locator was located at the heart of the ALEPH experiment, one of the four experiments at the Large Electron-Positron (LEP) collider. In the experiments at CERN's LEP, which ran from 1989 to 2000, modern silicon microvertex detectors, such as those used at ALEPH, monitored the production of short-lived particles close to the beam pipe.

  1. Tracking and vertexing at ATLAS

    OpenAIRE

    Ferrari, Pamela

    2007-01-01

    Several algorithms for tracking and for primary and secondary vertex reconstruction have been developed by the ATLAS collaboration following different approaches. This has allowed a thorough cross-check of the performances of the algorithms and of the reconstruction software. The results of the most recent studies on this topic are discussed and compared.

  2. Vertex algebras and mirror symmetry

    International Nuclear Information System (INIS)

    Borisov, L.A.

    2001-01-01

    Mirror Symmetry for Calabi-Yau hypersurfaces in toric varieties is by now well established. However, previous approaches to it did not uncover the underlying reason for mirror varieties to be mirror. We are able to calculate explicitly vertex algebras that correspond to holomorphic parts of A and B models of Calabi-Yau hypersurfaces and complete intersections in toric varieties. We establish the relation between these vertex algebras for mirror Calabi-Yau manifolds. This should eventually allow us to rewrite the whole story of toric mirror symmetry in the language of sheaves of vertex algebras. Our approach is purely algebraic and involves simple techniques from toric geometry and homological algebra, as well as some basic results of the theory of vertex algebras. Ideas of this paper may also be useful in other problems related to maps from curves to algebraic varieties.This paper could also be of interest to physicists, because it contains explicit description of holomorphic parts of A and B models of Calabi-Yau hypersurfaces and complete intersections in terms of free bosons and fermions. (orig.)

  3. EAMJ Vertex June.indd

    African Journals Online (AJOL)

    2009-06-06

    Jun 6, 2009 ... haematoma who presented with signs of severe head injury with upper limb decerebrate posture. We discuss the ... B. Axial CT image in bone window setting showing the bilateral linear parietal fracture (open arrow) at the vertex. A. B. Anterior (Frontal area). Scalp incision for craniotomy. Posterior (Occipital ...

  4. Nonequilibrium molecular dynamics

    Directory of Open Access Journals (Sweden)

    Wm.G.Hoover

    2005-01-01

    Full Text Available Nonequilibrium Molecular Dynamics is a powerful simulation tool. Like its equilibrium cousin, nonequilibrium molecular dynamics is based on time-reversible equations of motion. But unlike conventional mechanics, nonequilibrium molecular dynamics provides a consistent microscopic basis for the irreversible macroscopic Second Law of Thermodynamics. We recall here how fast computers led to the development of nonequilibrium molecular dynamics from the statistical mechanics of the 1950s. Computer-based theories facilitated revolutionary breakthroughs in understanding during the 1970s and 1980s. The new idea key to the nonequilibrium development was the replacement of the external thermodynamic environment by internal control variables. The new variables can control temperature, or pressure, or energy, or stress, or heat flux. These thermostat, barostat, ergostat, ... variables can control and maintain nonequilibrium states. We illustrate the methods with a simple example well-suited to student exploration, a thermostatted harmonic oscillator exposed to a temperature gradient.

  5. A Novel Vertex Affinity for Community Detection

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Andy [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sanders, Geoffrey [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Henson, Van [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Vassilevski, Panayot [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-10-05

    We propose a novel vertex affinity measure in this paper. The new vertex affinity quantifies the proximity between two vertices in terms of their clustering strength and is ideal for such graph analytics applications as community detection. We also developed a framework that combines simple graph searches and resistance circuit formulas to compute the vertex affinity efficiently. We study the properties of the new affinity measure empirically in comparison to those of other popular vertex proximity metrics. Our results show that the existing metrics are ill-suited for community detection due to their lack of fundamental properties that are essential for correctly capturing inter- and intra-cluster vertex proximity.

  6. The S-matrix bootstrap. Part I: QFT in AdS

    Science.gov (United States)

    Paulos, Miguel F.; Penedones, Joao; Toledo, Jonathan; van Rees, Balt C.; Vieira, Pedro

    2017-11-01

    We propose a strategy to study massive Quantum Field Theory (QFT) using conformal bootstrap methods. The idea is to consider QFT in hyperbolic space and study correlation functions of its boundary operators. We show that these are solutions of the crossing equations in one lower dimension. By sending the curvature radius of the background hyperbolic space to infinity we expect to recover flat-space physics. We explain that this regime corresponds to large scaling dimensions of the boundary operators, and discuss how to obtain the flat-space scattering amplitudes from the corresponding limit of the boundary correlators. We implement this strategy to obtain universal bounds on the strength of cubic couplings in 2D flat-space QFTs using 1D conformal bootstrap techniques. Our numerical results match precisely the analytic bounds obtained in our companion paper using S-matrix bootstrap techniques.

  7. arXiv The S-matrix Bootstrap I: QFT in AdS

    CERN Document Server

    Paulos, Miguel F.; Toledo, Jonathan; van Rees, Balt C.; Vieira, Pedro

    2017-11-21

    We propose a strategy to study massive Quantum Field Theory (QFT) using conformal bootstrap methods. The idea is to consider QFT in hyperbolic space and study correlation functions of its boundary operators. We show that these are solutions of the crossing equations in one lower dimension. By sending the curvature radius of the background hyperbolic space to infinity we expect to recover flat-space physics. We explain that this regime corresponds to large scaling dimensions of the boundary operators, and discuss how to obtain the flat-space scattering amplitudes from the corresponding limit of the boundary correlators. We implement this strategy to obtain universal bounds on the strength of cubic couplings in 2D flat-space QFTs using 1D conformal bootstrap techniques. Our numerical results match precisely the analytic bounds obtained in our companion paper using S-matrix bootstrap techniques.

  8. 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

  9. STAR Vertex Detector Upgrade Development

    Energy Technology Data Exchange (ETDEWEB)

    Greiner, Leo C.; Matis, Howard S.; Stezelberger, Thorsten; Vu,Chinh Q.; Wieman, Howard; Szelezniak, Michal; Sun, Xiangming

    2008-01-28

    We report on the development and prototyping efforts undertaken with the goal of producing a micro-vertex detector for the STAR experiment at the RHIC accelerator at BNL. We present the basic detector requirements and show a sensor development path, conceptual mechanical design candidates and readout architecture. Prototyping and beam test results with current generation MimoSTAR-2 sensors and a readout system featuring FPGA based on-the-fly hit finding and data sparsification are also presented.

  10. STAR Vertex Detector Upgrade Development

    International Nuclear Information System (INIS)

    Greiner, Leo C.; Matis, Howard S.; Stezelberger, Thorsten; Vu, Chinh Q.; Wieman, Howard; Szelezniak, Michal; Sun, Xiangming

    2008-01-01

    We report on the development and prototyping efforts undertaken with the goal of producing a micro-vertex detector for the STAR experiment at the RHIC accelerator at BNL. We present the basic detector requirements and show a sensor development path, conceptual mechanical design candidates and readout architecture. Prototyping and beam test results with current generation MimoSTAR-2 sensors and a readout system featuring FPGA based on-the-fly hit finding and data sparsification are also presented

  11. Lectures on the Topological Vertex

    CERN Document Server

    Mariño, M

    2008-01-01

    In this lectures, I will summarize the approach to Gromov–Witten invariants on toric Calabi–Yau threefolds based on large N dualities. Since the large N duality/topological vertex approach computes Gromov–Witten invariants in terms of Chern–Simons knot and link invariants, Sect. 2 is devoted to a review of these. Section 3 reviews topological strings and Gromov–Witten invariants, and gives some information about the open string case. Section 4 introduces the class of geometries we will deal with, namely toric (noncompact) Calabi–Yau manifolds, and we present a useful graphical way to represent these manifolds which constitutes the geometric core of the theory of the topological vertex. Finally, in Sect. 5, we define the vertex and present some explicit formulae for it and some simple applications. A brief Appendix contains useful information about symmetric polynomials. It has not been possible to present all the relevant background and physical derivations in this set of lectures. However, these...

  12. Identifying vertex covers in graphs

    DEFF Research Database (Denmark)

    Henning, Michael A.; Yeo, Anders

    2012-01-01

    An identifying vertex cover in a graph G is a subset T of vertices in G that has a nonempty intersection with every edge of G such that T distinguishes the edges, that is, e∩T ≠ 0 for every edge e in G and e∩T ≠ f∩T for every two distinct edges e and f in G. The identifying vertex cover number TD......(G) of G is the minimum size of an identifying vertex cover in G. We observe that TD(G)+ρ(G) = |V (G)|, where ρ(G) denotes the packing number of G. We conjecture that if G is a graph of order n and size m with maximum degree Δ, then TD(G) ≤(Δ(Δ-1)/ Δ2+1)n + (2/Δ2+1) m. If the conjecture is true......, then the bound is best possible for all Δ ≥ 1. We prove this conjecture when Δ ≥ 1 and G is a Δ-regular graph. The three known Moore graphs of diameter 2, namely the 5-cycle, the Petersen graph and the Hoffman-Singleton graph, are examples of regular graphs that achieves equality in the upper bound. We also...

  13. The LHCb Vertex Locator performance and Vertex Locator upgrade

    CERN Document Server

    INSPIRE-00259789

    2012-01-01

    LHCb is an experiment dedicated to the study of new physics in the decays of beauty and charm hadrons at the Large Hadron Collider (LHC) at CERN. The Vertex Locator (VELO) is the silicon detector surrounding the LHCb interaction point. The detector operates in a severe and highly non-uniform radiation environment. The small pitch and analogue readout result in a best single hit precision of 4 $\\rm \\mu$m. The upgrade of the LHCb experiment, planned for 2018, will transform the entire readout to a trigger-less system operating at 40 MHz event rate. The vertex detector will have to cope with radiation levels up to 10$^{16}$ 1 MeV$\\rm n_{eq}/cm^2$, more than an order of magnitude higher than those expected at the current experiment. A solution is under development with a pixel detector, based on the Timepix/Medipix family of chips with 55 x 55 $\\rm \\mu m$ pixels. In addition a micro-strip solution is also under development, with finer pitch, higher granularity and lower mass than the current detector. The current...

  14. The connection from the Sun to Planets and the Galaxy by QFT

    Science.gov (United States)

    Chen, Shao-Guang

    I deduce the new gravitational formula from the variance in mass of QFT and GR (H05-0029-08, E15-0039 -08, E14-0032-08, D31-0054-10) in the partial differential: f (QFT) = f (GR) = delta∂ (m v)/delta∂ t = f _{P} + f _{C} , f _{P} = m delta∂ v / delta∂ t = - ( G m M /r (2) ) r / r, f _{C} = v delta∂ m / delta∂ t = - ( G mM / r (2) ) v / c (1), f (QFT) is the quasi-Casimir pressure of net virtual neutrinos nuν _{0} flux (after counteract contrary direction nuν _{0}). f (GR) is equivalent to Einstein’s equation as a new version of GR. GR can be inferred from Eq.(1) thereby from QFT, but QFT cannot be inferred from Eq.(1) or GR. f (QFT) is essential but f (GR) is phenomenological. Eq.(1) is obtained just by to absorb the essence of corpuscule collided gravitation origin ism proposed by Fatio in 1690 and 1920 Majorana’s experiment concept about gravitational shield effect again fuse with QFT. Its core content is that the gravity produced by particles collide cannot linear addition, i.e., Eq.(1) with the adding nonlinearity caused by the variable mass to replace the nonlinearity of Einstein’s equation and the nonlinear gravitation problems can be solved using the classical gradual approximation of alone f _{P} and alone f _{C}. Such as the calculation of advance of the perihelion of QFT, let the gravitational potential U = - G M /r which is just the distribution density of net nuν _{0} flux. From SR we again get Eq.(1): f (QFT) = f _{P} + f _{C}, f _{P} = - m ( delta∂ U / delta∂ r) r / r, f _{C} = - m ( delta∂U / delta∂ r) v / c , U = (1 - betaβ (2) )V, V is the Newtonian gravitational potential. f_{ P} correspond the change rate of three-dimensional momentum p, f_{C} correspond the change rate of fourth dimensional momentum i m c which show directly as a dissipative force of mass change. In my paper ‘To cross the great gap between the modern physics and classic physics, China Science &Technology Overview 129 85-91(2011)’ with the

  15. CCD-based vertex detectors

    CERN Document Server

    Damerell, C J S

    2005-01-01

    Over the past 20 years, CCD-based vertex detectors have been used to construct some of the most precise 'tracking microscopes' in particle physics. They were initially used by the ACCMOR collaboration for fixed target experiments in CERN, where they enabled the lifetimes of some of the shortest-lived charm particles to be measured precisely. The migration to collider experiments was accomplished in the SLD experiment, where the original 120 Mpixel detector was later upgraded to one with 307 Mpixels. This detector was used in a range of physics studies which exceeded the capability of the LEP detectors, including the most precise limit to date on the Bs mixing parameter. This success, and the high background hit densities that will inevitably be encountered at the future TeV-scale linear collider, have established the need for a silicon pixel-based vertex detector at this machine. The technical options have now been broadened to include a wide range of possible silicon imaging technologies as well as CCDs (mon...

  16. Nonequilibrium molecular dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Hoover, W.G. (California Univ., Davis, CA (USA). Dept. of Applied Science Lawrence Livermore National Lab., CA (USA))

    1990-11-01

    The development of nonequilibrium molecular dynamics is described, with emphasis on massively-parallel simulations involving the motion of millions, soon to be billions, of atoms. Corresponding continuum simulations are also discussed. 14 refs., 8 figs.

  17. Vertex Tracking at a Future Linear Collider

    CERN Document Server

    Battaglia, Marco

    2011-01-01

    The anticipated physics program at an high energy e+e- linear collider places special emphasis on the accuracy in extrapolating charged particle tracks to their production vertex to tag heavy quarks and leptons. This paper reviews physics motivations and performance requirements, sensor R&D directions and current results of the studies for a vertex tracker at a future linear collider.

  18. New vertex reconstruction algorithms for CMS

    CERN Document Server

    Frühwirth, R; Prokofiev, Kirill; Speer, T.; Vanlaer, P.; Chabanat, E.; Estre, N.

    2003-01-01

    The reconstruction of interaction vertices can be decomposed into a pattern recognition problem (``vertex finding'') and a statistical problem (``vertex fitting''). We briefly review classical methods. We introduce novel approaches and motivate them in the framework of high-luminosity experiments like at the LHC. We then show comparisons with the classical methods in relevant physics channels

  19. Vertex Reconstruction in ATLAS Run II

    CERN Document Server

    Zhang, Matt; The ATLAS collaboration

    2016-01-01

    Vertex reconstruction is the process of taking reconstructed tracks and using them to determine the locations of proton collisions. In this poster we present the performance of our current vertex reconstruction algorithm, and look at investigations into potential improvements from a new seed finding method.

  20. The heating and acceleration actions of the solar plasma wave by QFT

    Science.gov (United States)

    Chen, Shao-Guang

    I deduce the new gravitational formula from the variance in mass of QFT and GR (H05-0029-08, E15-0039 -08, E14-0032-08, D31-0054-10) in the partial differential: f (QFT) = f (GR) = delta∂ (m v)/delta∂ t = f _{P} + f _{C} , f _{P} = m delta∂ v / delta∂ t = - ( G m M /r (2) ) r / r, f _{C} = v delta∂ m / delta∂ t = - ( G mM / r (2) ) v / c (1), f (QFT) is the quasi-Casimir pressure of net virtual neutrinos nuν _{0} flux (after counteract contrary direction nuν _{0}). f (GR) is equivalent to Einstein’s equation as a new version of GR. GR can be inferred from Eq.(1) thereby from QFT, but QFT cannot be inferred from Eq.(1) or GR. f (QFT) is essential but f (GR) is phenomenological. Eq.(1) is obtained just by to absorb the essence of corpuscule collided gravitation origin ism proposed by Fatio in 1690 and 1920 Majorana’s experiment concept about gravitational shield effect again fuse with QFT. Its core content is that the gravity produced by particles collide cannot linear addition, i.e., Eq.(1) with the adding nonlinearity caused by the variable mass to replace the nonlinearity of Einstein’s equation and the nonlinear gravitation problems can be solved using the classical gradual approximation of alone f _{P} and alone f _{C}. Such as the calculation of advance of the perihelion of QFT, let the gravitational potential U = - G M /r which is just the distribution density of net nuν _{0} flux. From SR we again get Eq.(1): f (QFT) = f _{P} + f _{C}, f _{P} = - m ( delta∂ U / delta∂ r) r / r, f _{C} = - m ( delta∂U / delta∂ r) v / c , U = (1 - betaβ (2) )V, V is the Newtonian gravitational potential. f_{ P} correspond the change rate of three-dimensional momentum p, f_{C} correspond the change rate of fourth dimensional momentum i m c which show directly as a dissipative force of mass change. In my paper ‘To cross the great gap between the modern physics and classic physics, China Science &Technology Overview 129 85-91(2011)’ with the

  1. Algebraic QFT as a framework for classification and model-building. A heretic view of the new kinematics

    International Nuclear Information System (INIS)

    Schroer, B.

    1990-01-01

    We show that the algebraic structure encountered first in conformal QFT 2 corresponds to the multiciplicity-free parastatistics description of H. Green of 1953. We give arguments in favour of the dictum that QFT, in contradistinction to Quantum Mechanics, does not have to rely on quantization but rather allows for a formulation and classification in terms of intrinsic quantum principles. We interpret the Karowski-Weisz-Smirnov form-factor program in this light and comment on some properties of anyons and plektons which may be relevant for condensed matter physics (the enigma of Non-Fermi-Liquid-States)

  2. Nonequilibrium statistical physics

    CERN Document Server

    Röpke, Gerd

    2013-01-01

    Authored by one of the top theoretical physicists in Germany, and a well-known authority in the field, this is the only coherent presentation of the subject suitable for masters and PhD students, as well as postdocs in physics and related disciplines.Starting from a general discussion of the nonequilibrium state, different standard approaches such as master equations, and kinetic and linear response theory, are derived after special assumptions. This allows for an insight into the problems of nonequilibrium physics, a discussion of the limits, and suggestions for improvements. Applications

  3. Spinfoam cosmology with the proper vertex amplitude

    Science.gov (United States)

    Vilensky, Ilya

    2017-11-01

    The proper vertex amplitude is derived from the Engle-Pereira-Rovelli-Livine vertex by restricting to a single gravitational sector in order to achieve the correct semi-classical behaviour. We apply the proper vertex to calculate a cosmological transition amplitude that can be viewed as the Hartle-Hawking wavefunction. To perform this calculation we deduce the integral form of the proper vertex and use extended stationary phase methods to estimate the large-volume limit. We show that the resulting amplitude satisfies an operator constraint whose classical analogue is the Hamiltonian constraint of the Friedmann-Robertson-Walker cosmology. We find that the constraint dynamically selects the relevant family of coherent states and demonstrate a similar dynamic selection in standard quantum mechanics. We investigate the effects of dynamical selection on long-range correlations.

  4. VERTEX ANTIMAGIC TOTAL LABELING PADA GRAPHMULTICYCLE

    Directory of Open Access Journals (Sweden)

    Dominikus Arif Budi Prasetyo pythagors

    2015-01-01

    Full Text Available Pelabelan graf merupakan bagian dari graf yang berkembang saat ini. Jenis pelabelan pada graf bergantungpada domainnya, yakni pelabelan sisi ajaib, pelabelan titik ajaib, dan pelabelan total ajaib. Pelabelan totalajaib pada graf dibedakan lagi berdasarkan komponen graf yang dievaluasi, yakni pelabelan total sisi ajaibdan pelabelan total titik ajaib. Pada pelabelan ajaib, bobot dari komponen graf yang dievaluasi adalah sama,jika bobotnya tidak sama maka dinamakan pelabelan tak-ajaib (antimagic. Misalkan G adalah graf denganbanyak titik p dan sisi q. Suatu pemetaan bijektif dari komponen-komponen graf ke bilangan bulat positif {1,2, …, (p+q} disebut called (a, d vertex antimagic total labelling (pelabelan total titik ajaib dari graf G jikabobot setiap titik (vertex merupakan barisan aritmetika naik. Pada artikel ini membahas bahwa grafmulticycle mCp memenuhi (a, d vertex antimagic total labelling dan beberapa bentuk pelabelannya.Kata kunci : graph multicycle, vertex antimagic total labeling

  5. Vertex occlusal radiography in localizing unerupted mesiodentes

    Directory of Open Access Journals (Sweden)

    P Chalakkal

    2011-01-01

    Full Text Available The aim was to compare the vertex occlusal projection with the anterior maxillary occlusal projection in localizing the position of mesiodentes. Mesiodentes were observed in an 8-year-old boy with an anterior maxillary occlusal radiograph. A vertex occlusal radiograph was taken to compare it with the former in terms of mesiodentes localization with respect to the maxillary central incisors. The vertex occlusal radiograph provided greater details of the position and proximity of mesiodentes with respect to the long axis of maxillary central incisors in comparison to the anterior maxillary occlusal radiograph. Vertex occlusal radiography is an important diagnostic tool in diagnosing the presence, position, and proximity of mesiodentes with respect to the long axis of normally aligned maxillary central incisors. However, it is not recommended for routine use in a patient as its radiation dose is higher than conventional intraoral radiographic methods.

  6. The LHCb Vertex Locator Upgrade

    Science.gov (United States)

    Szumlak, T.

    2017-12-01

    The Large Hadron Collider beauty LHCb detector is a dedicated flavour physics experiment, designed to efficiently detect decays of b- and c-hadrons to perform precise studies of CP violation and rare decays. At the end of Run 2, many of the LHCb measurements will remain statistically dominated. In order to increase the trigger yield for purely hadronic channels, the hardware trigger will be removed, and the full detector will be read out at 40 MHz. This, in combination with the five-fold increase in luminosity necessitates radical changes to LHCb's electronics with entire subdetector replacements required in some cases. The Vertex Locator (VELO) surrounding the interaction region is used to reconstruct the proton-proton collision points (primary vertices) and decay vertices of long-lived particles (secondary vertices). The upgraded VELO will be equipped with silicon hybrid pixel sensors, each read out by VeloPix ASICs. The highest occupancy ASICs will have pixel hit rates of 900 Mhit/s and produce an output data rate of over 15 Gbit/s, with a total rate of 1.6 Tbit/s anticipated for the whole detector. Selected highlights of this challenging and ambitious project are described in this paper.

  7. Diagnostic usefulness of the QuantiFERON-TB gold in-tube test (QFT-GIT) for tuberculous vertebral osteomyelitis.

    Science.gov (United States)

    Choi, Sungim; Jung, Kyung Hwa; Son, Hyo-Ju; Lee, Seung Hyun; Hong, Jung Min; Kim, Min Chul; Kim, Min Jae; Chong, Yong Pil; Sung, Heungsup; Lee, Sang-Oh; Choi, Sang-Ho; Kim, Yang Soo; Woo, Jun Hee; Kim, Sung-Han

    2018-05-01

    Interferon (IFN)-γ-releasing assay for diagnosing tuberculosis (TB) has shown promise; however, there are only a few reports on usefulness of the QuantiFERON-TB Gold In-Tube test (QFT-GIT) for diagnosing TB vertebral osteomyelitis. All patients presenting at a tertiary hospital between January 2010 and July 2016 with suspected TB vertebral osteomyelitis were retrospectively enrolled to evaluate the diagnostic performance of QFT-GIT. We used QFT-GIT to measure the IFN-γ response to ESAT-6, CFP-10 and TB7.7. A total of 141 patients were enrolled; 32 (23%) were categorized as having confirmed TB, (1%) as probable TB, 14 (10%) as possible TB and 93 (66%) as not TB. Of these, 16 patients with probable and possible TB were excluded from the final analysis. Chronic granulomas with/without necrosis, acid-fast bacilli stain, M. tuberculosis polymerase chain reaction and cultures for M. tuberculosis were positive in 14 (44%), 12 (38%), 22 (69%) and 28 (88%) patients, respectively, among the 32 patients with confirmed TB. The overall sensitivity, specificity, positive predictive value, negative predictive value, likelihood ratio for a positive result, and likelihood ratio for a negative result of the QFT-GIT for TB vertebral osteomyelitis were 91% (95% confidence interval [CI], 75-98%), 65% (95% CI, 54-75%), 50% (95% CI, 42-58%), 95% (95% CI, 86-98%), 2.59 (95% CI, 1.89-3.55) and 0.14 (95% CI, 0.05-0.43), respectively. The QFT-GIT appears to be a useful adjunct test for diagnosing TB vertebral osteomyelitis because the negative test results may be useful for excluding a diagnosis of active TB vertebral osteomyelitis.

  8. Domination Number of Vertex Amalgamation of Graphs

    Science.gov (United States)

    Wahyuni, Y.; Utoyo, M. I.; Slamin

    2017-06-01

    For a graph G = (V, E), a subset S of V is called a dominating set if every vertex x in V is either in S or adjacent to a vertex in S. The domination number γ ( G ) is the minimum cardinality of the dominating set of G. The dominating set of G with a minimum cardinality denoted by γ ( G )-set. Let G 1, G 2, …, Gt be subgraphs of the graph G. If the union of all these subgraphs is G and their intersection is {v}, then we say that G is the vertex-amalgamation of G 1, G 2, …, Gt at vertex v. Based on the membership of the common vertex v in the γ ( Gi )-set, there exist three conditions to be considered. First, if v elements of every γ ( Gi )-set, second if there is no γ ( Gi )-set containing v, and third if either v is element of γ ( Gi )-set for 1 ≤ i ≤ p or there is no γ ( Gi )-set containing v for p amalgamation of G 1, G 2, …, Gt at vertex v can be determined.

  9. Nonequilibrium thermodynamics of nucleation

    NARCIS (Netherlands)

    Schweizer, M.; Sagis, L.M.C.

    2014-01-01

    We present a novel approach to nucleation processes based on the GENERIC framework (general equation for the nonequilibrium reversible-irreversible coupling). Solely based on the GENERIC structure of time-evolution equations and thermodynamic consistency arguments of exchange processes between a

  10. Alignment of the LHCb vertex locator

    International Nuclear Information System (INIS)

    Gersabeck, M.

    2009-01-01

    LHCb will commence data taking as the first dedicated heavy flavour experiment at a hadron collider in 2008. A very high hit precision from its vertex detector (vertex locator, VELO) is essential to meet the tight requirements of vertex reconstruction in B-physics. The single hit precision of the VELO is better than 10μm. However, the VELO is operated only 8 mm from the beam and must be retracted and reinserted each LHC fill. Hence, the detector places unique demands on its alignment algorithm. The partially assembled VELO system has already been tested in a beam test. The novel software alignment methods are presented together with their interplay with the metrology measurements. Results from Monte Carlo simulation studies are discussed and recent beam test results are shown that prove the method's precision at the micron level.

  11. Quantum vertex model for reversible classical computing.

    Science.gov (United States)

    Chamon, C; Mucciolo, E R; Ruckenstein, A E; Yang, Z-C

    2017-05-12

    Mappings of classical computation onto statistical mechanics models have led to remarkable successes in addressing some complex computational problems. However, such mappings display thermodynamic phase transitions that may prevent reaching solution even for easy problems known to be solvable in polynomial time. Here we map universal reversible classical computations onto a planar vertex model that exhibits no bulk classical thermodynamic phase transition, independent of the computational circuit. Within our approach the solution of the computation is encoded in the ground state of the vertex model and its complexity is reflected in the dynamics of the relaxation of the system to its ground state. We use thermal annealing with and without 'learning' to explore typical computational problems. We also construct a mapping of the vertex model into the Chimera architecture of the D-Wave machine, initiating an approach to reversible classical computation based on state-of-the-art implementations of quantum annealing.

  12. First Results from the LHCb Vertex Locator

    CERN Document Server

    Borghi, S

    2010-01-01

    LHCb is a dedicated experiment to study new physics in the decays of beauty and charm hadrons at the Large Hadron Collider (LHC) at CERN. The Vertex Locator (VELO) is the silicon detector surrounding the interaction point, and compared to the vertex detectors of the other LHC experiments, it is the closest LHC vertex detector to the beam interaction point, being located only 7 mm from the beam during normal operation. The detector operates in an extreme and highly non-uniform radiation environment. The VELO consists of two retractable detector halves with 21 silicon micro-strip tracking modules each. The VELO has been commissioned and successfully operated during the initial running period of the LHC. The preliminary operational results and detector performances are reported.

  13. A note on arbitrarily vertex decomposable graphs

    Directory of Open Access Journals (Sweden)

    Antoni Marczyk

    2006-01-01

    Full Text Available A graph \\(G\\ of order \\(n\\ is said to be arbitrarily vertex decomposable if for each sequence \\((n_{1},\\ldots,n_k\\ of positive integers such that \\(n_{1}+\\ldots+n_{k}=n\\ there exists a partition \\((V_{1},\\ldots,V_{k}\\ of the vertex set of \\(G\\ such that for each \\(i \\in \\{1,\\ldots,k\\}\\, \\(V_{i}\\ induces a connected subgraph of \\(G\\ on \\(n_i\\ vertices. In this paper we show that if \\(G\\ is a two-connected graph on \\(n\\ vertices with the independence number at most \\(\\lceil n/2\\rceil\\ and such that the degree sum of any pair of non-adjacent vertices is at least \\(n-3\\, then \\(G\\ is arbitrarily vertex decomposable. We present another result for connected graphs satisfying a similar condition, where the bound \\(n-3\\ is replaced by \\(n-2\\.

  14. Statistical mechanics of nonequilibrium liquids

    CERN Document Server

    Evans, Denis J; Craig, D P; McWeeny, R

    1990-01-01

    Statistical Mechanics of Nonequilibrium Liquids deals with theoretical rheology. The book discusses nonlinear response of systems and outlines the statistical mechanical theory. In discussing the framework of nonequilibrium statistical mechanics, the book explains the derivation of a nonequilibrium analogue of the Gibbsian basis for equilibrium statistical mechanics. The book reviews the linear irreversible thermodynamics, the Liouville equation, and the Irving-Kirkwood procedure. The text then explains the Green-Kubo relations used in linear transport coefficients, the linear response theory,

  15. The vertex detector trigger data model

    CERN Document Server

    Koratzinos, M

    1998-01-01

    The aim of this note is to discuss the various issues arising from Different choices in the design of the Vertex Trigger Data Model and define a Baseline model. The pros and cons of the different choices will be presented with A recommendation of which choice constitutes the baseline solution and with a suggestion of the work plan to arrive to the final solution. This note does not try and define the definite version of the data model. However it is important to have a first version at this stage of the Vertex Trigger project.

  16. Vertex Reconstruction for AEGIS’ FACT Detector

    CERN Document Server

    Themistokleous, Neofytos

    2017-01-01

    My project dealt with the development of a vertex reconstruction technique to discriminate antihydrogen from background signals in the AEGIS apparatus. It involved the creation of a Toy Monte-Carlo to simulate particle annihilation events, and a vertex reconstruction utility based on the Bayesian theory of probability. The first results based on 107 generated events with single track in the detector are encouraging. For such events, the algorithm can reconstruct the z-coordinate accurately , while for the r-coordinate the result is less accurate.

  17. Vertex Detector Performance for CLICdet, FCCee & FCChh.

    CERN Document Server

    Rasmussen, Peter Winkel

    2017-01-01

    The performance of the vertex detectors planned for CLICdet, FCCee & FCChh was tested in this project. This was done my studying the figure of merit for a vertex detector which is the transverse impact parameter resolution $\\sigma(d_0)$. This was carried out by simulating single $\\mu^-$ at different energies, polar angles, $\\theta$ with a uniform distribution in the azimuthal angle $\\phi$. The events were reconstructed and the distribution $\\Delta(d_0) = d_{0,reco}-d_{0,true}$ was fitted with a Gaussian function where the width of the function resulted in $\\sigma(d_0)$. The effect of material budget and fit function on this was also tested.

  18. Primary vertex reconstruction at the ATLAS experiment

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00301388; The ATLAS collaboration; Casper, D.; Hooberman, B.; Gui, B.; Lee, G.; Maurer, J.; Morley, A.; Pagan Griso, S.; Petersen, B.; Prokofiev, K.; Shan, L.; Shope, D.; Wharton, A.; Whitmore, B.; Zhang, M.

    2017-01-01

    These proceedings present the method and performance of primary vertex reconstruction at the ATLAS experiment during Runs 1 and 2 at the LHC. The studies presented focus on data taken during 2012 at a centre-of-mass energy of $\\sqrt{s} = 8$ TeV, and during 2015-2016 at $\\sqrt{s} = 13$ TeV. Some predictions toward future runs are also presented. The measurement of the position and size of the luminous region and its use as a constraint to improve the primary vertex resolution are discussed.

  19. Improving vertex position determination by using a kinematic fit

    International Nuclear Information System (INIS)

    Forden, G.E.; Saxon, D.H.

    1985-05-01

    A method is developed for improving decay vertex reconstruction by using kinematic fits. This is applied to generated charm meson decays. An improvement of 16% in the vertex position measurement along the flight path is achieved. (author)

  20. Cluster algebras bases on vertex operator algebras

    Czech Academy of Sciences Publication Activity Database

    Zuevsky, Alexander

    2016-01-01

    Roč. 30, 28-29 (2016), č. článku 1640030. ISSN 0217-9792 Institutional support: RVO:67985840 Keywords : cluster alegbras * vertex operator algebras * Riemann surfaces Subject RIV: BA - General Mathematics Impact factor: 0.736, year: 2016 http://www.worldscientific.com/doi/abs/10.1142/S0217979216400300

  1. Primary Vertex Reconstruction with the ATLAS Experiment

    CERN Document Server

    Casper, David William; The ATLAS collaboration

    2017-01-01

    ATLAS reconstructs primary vertices with high efficiency and resolution. These vertices serve as input to other mission critical analysis tools, and are relied on by many physics analyses. This presentation surveys the ATLAS primary vertex reconstruction algorithms, and describes validity checks done using real data. The complications introduced by pileup are discussed, along with refinements currently under study.

  2. LHCb Vertex Locator Upgrade Work Report

    CERN Document Server

    Estrada, Michael

    2017-01-01

    As the LHCb prepares for the planned upgrade of its vertex locator, there is a great need for supporting work such as the design and testing of apparatus that will ensure the smooth implementation of new hardware and infrastructure. My work this summer consisted largely of tasks to support this process.

  3. Algebraic characterization of the Witten vertex

    International Nuclear Information System (INIS)

    Embacher, F.

    1989-01-01

    The Witten vertex of open bosonic string field theory is characterized by a set of algebraic properties written down in the Fock-space operator formalism. The typical 3-string overlap structure as well as the correct ghost midpoint insertion are not required from the outset but arise as consequences. 20 refs. (Author)

  4. Primary Vertex Reconstruction at the ATLAS Experiment

    CERN Document Server

    Grimm, Kathryn; The ATLAS collaboration

    2016-01-01

    Efficient and precise reconstruction of the primary vertex in an LHC collision is essential in both the reconstruction of the full kinematic properties of a hard-scatter event and of soft interactions as a measure of the amount of pile-up. The reconstruction of primary vertices in the busy, high pile-up environment of Run-2 of the LHC is a challenging task. New methods have been developed by the ATLAS experiment to reconstruct vertices in such environments. Advances in vertex seeding include methods taken from medical imaging, which allow for reconstruction of multiple vertices with small spatial separation. The adoption of this new seeding algorithm within the ATLAS adaptive vertex finding and fitting procedure will be discussed, and the first results of the new techniques from Run-2 data will be presented. Additionally, data-driven methods to evaluate vertex resolution will be presented with special focus on correct methods to evaluate the effect of the beam spot constraint; results from these methods in Ru...

  5. Twisted Frobenius Identities from Vertex Operator Superalgebras

    Directory of Open Access Journals (Sweden)

    Alexander Zuevsky

    2017-01-01

    Full Text Available In consideration of the continuous orbifold partition function and a generating function for all n-point correlation functions for the rank two free fermion vertex operator superalgebra on the self-sewing torus, we introduce the twisted version of Frobenius identity.

  6. Twisted Frobenius identies from vertex operator superalgebras

    Czech Academy of Sciences Publication Activity Database

    Zuevsky, Alexander

    2017-01-01

    Roč. 2017, 9 November (2017), č. článku 2340410. ISSN 1687-9120 Institutional support: RVO:67985840 Keywords : vertex operator superalgebras * intertwining operators * Riemann surfaces Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 0.643, year: 2016 https://www.hindawi.com/journals/amp/2017/2340410/

  7. Lifetime tests for MAC vertex chamber

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, H.N.

    1986-07-01

    A vertex chamber for MAC was proposed to increase precision in the measurement of the B hadron and tau lepton lifetimes. Thin-walled aluminized mylar drift tubes were used for detector elements. A study of radiation hardness was conducted under the conditions of the proposed design using different gases and different operating conditions. (LEW)

  8. Characterisations of Intersection Graphs by Vertex Orderings

    OpenAIRE

    Wood, David R.

    2004-01-01

    Characterisations of interval graphs, comparability graphs, co-comparability graphs, permutation graphs, and split graphs in terms of linear orderings of the vertex set are presented. As an application, it is proved that interval graphs, co-comparability graphs, AT-free graphs, and split graphs have bandwidth bounded by their maximum degree.

  9. Non-equilibrium thermodynamics

    CERN Document Server

    De Groot, Sybren Ruurds

    1984-01-01

    The study of thermodynamics is especially timely today, as its concepts are being applied to problems in biology, biochemistry, electrochemistry, and engineering. This book treats irreversible processes and phenomena - non-equilibrium thermodynamics.S. R. de Groot and P. Mazur, Professors of Theoretical Physics, present a comprehensive and insightful survey of the foundations of the field, providing the only complete discussion of the fluctuating linear theory of irreversible thermodynamics. The application covers a wide range of topics: the theory of diffusion and heat conduction, fluid dyn

  10. The nonequilibrium molecular dynamics

    International Nuclear Information System (INIS)

    Hoover, W.G.

    1992-03-01

    MOLECULAR DYNAMICS has been generalized in order to simulate a variety of NONEQUILIBRIUM systems. This generalization has been achieved by adopting microscopic mechanical definitions of macroscopic thermodynamic and hydrodynamic variables, such as temperature and stress. Some of the problems already treated include rapid plastic deformation, intense heat conduction, strong shockwaves simulation, and far-from-equilibrium phase transformations. Continuing advances in technique and in the modeling of interatomic forces, coupled with qualitative improvements in computer hardware, are enabling such simulations to approximate real-world microscale and nanoscale experiments

  11. Virasoro conditions, vertex operators, and string dynamics in curved space

    International Nuclear Information System (INIS)

    Jain, S.; Mandal, G.; Wadia, S.R.

    1987-01-01

    We present the perturbatively renormalized expression of a scalar vertex operator for strings in a background metric and dilaton field. The equations of motion for the background fields and the wave equation for the vertex function emerge upon imposing Virasoro conditions on the vertex operator

  12. Certain extensions of vertex operator algebras of affine type

    International Nuclear Information System (INIS)

    Li Haisheng

    2001-01-01

    We generalize Feigin and Miwa's construction of extended vertex operator (super)algebras A k (sl(2)) for other types of simple Lie algebras. For all the constructed extended vertex operator (super)algebras, irreducible modules are classified, complete reducibility of every module is proved and fusion rules are determined modulo the fusion rules for vertex operator algebras of affine type. (orig.)

  13. The 16-vertex model and its even and odd 8-vertex subcases on the square lattice

    Science.gov (United States)

    Assis, Michael

    2017-09-01

    We survey and enlarge the known mappings of the 16-vertex model, with emphasis on mappings between the even and odd 8-vertex subcases of the general model, also giving new mappings between these models, valid on finite toroidal lattices. In particular, we find new mappings between the models by using their algebraic invariants with respect to the SL(2)× SL(2) symmetry of the 16-vertex model; we also find a larger set of weak-graph transformations. We show many examples of models with negative weights which map to models with only positive weights. Using the algebraic invariant relations of the even and odd 8-vertex models, we find the complete set of points in the complex field plane of the square lattice Ising model in a field which map to the even or odd 8-vertex models; these points also correspond to the set of free-fermionic points of the model. We do not find any new integrable points, but we find a new mapping between the odd 8-vertex model and the square lattice Ising model at magnetic field H= iπ/(2β) , valid on finite toroidal lattices. We also show directly through various examples that mappings via algebraic invariants do not fully exhaust the possible mappings a model may have with another model. We construct a new solution to the odd 8-vertex free-fermion model which is valid on the finite lattice, since the previous known solution resulted from a mapping valid only in the thermodynamic limit. Finally, we detail for the first time the phase transitions of the column staggered free-fermion 8-vertex model, and show that it can be mapped to the bi-partite staggered free-fermion model.

  14. ILC Vertex Tracker R&D

    Energy Technology Data Exchange (ETDEWEB)

    Battaglia, Marco; Bussat, Jean-Marie; Contarato, Devis; Denes,Peter; Glesener, Lindsay; Greiner, Leo; Hooberman, Benjamin; Shuman,Derek; Tompkins, Lauren; Vu, Chinh; Bisello, Dario; Giubilato, Piero; Pantano, Devis; Costa, Marco; La Rosa, Alessandro; Bolla, Gino; Bortoletto, Daniela; Children, Isaac

    2007-10-01

    This document summarizes past achievements, current activities and future goals of the R&D program aimed at the design, prototyping and characterization of a full detector module, equipped with monolithic pixel sensors, matching the requirements for the Vertex Tracker at the ILC. We provide a plan of activities to obtain a demonstrator multi-layered vertex tracker equipped with sensors matching the ILC requirements and realistic lightweight ladders in FY11, under the assumption that ILC detector proto-collaborations will be choosing technologies and designs for the Vertex Tracker by that time. The R&D program discussed here started at LBNL in 2004, supported by a Laboratory Directed R&D (LDRD) grant and by funding allocated from the core budget of the LBNL Physics Division and from the Department of Physics at UC Berkeley. Subsequently additional funding has been awarded under the NSF-DOE LCRD program and also personnel have become available through collaborative research with other groups. The aim of the R&D program carried out by our collaboration is to provide a well-integrated, inclusive research effort starting from physics requirements for the ILC Vertex Tracker and addressing Si sensor design and characterization, engineered ladder design, module system issues, tracking and vertex performances and beam test validation. The broad scope of this program is made possible by important synergies with existing know-how and concurrent programs both at LBNL and at the other collaborating institutions. In particular, significant overlaps with LHC detector design, SLHC R&D as well as prototyping for the STAR upgrade have been exploited to optimize the cost per deliverable of our program. This activity is carried out as a collaborative effort together with Accelerator and Fusion Research, the Engineering and the Nuclear Science Divisions at LBNL, INFN and the Department of Physics in Padova, Italy, INFN and the Department of Physics in Torino, Italy and the Department

  15. Non-equilibrium Economics

    Directory of Open Access Journals (Sweden)

    Katalin Martinás

    2007-02-01

    Full Text Available A microeconomic, agent based framework to dynamic economics is formulated in a materialist approach. An axiomatic foundation of a non-equilibrium microeconomics is outlined. Economic activity is modelled as transformation and transport of commodities (materials owned by the agents. Rate of transformations (production intensity, and the rate of transport (trade are defined by the agents. Economic decision rules are derived from the observed economic behaviour. The non-linear equations are solved numerically for a model economy. Numerical solutions for simple model economies suggest that the some of the results of general equilibrium economics are consequences only of the equilibrium hypothesis. We show that perfect competition of selfish agents does not guarantee the stability of economic equilibrium, but cooperativity is needed, too.

  16. Alignment of the LHCb Vertex Locator

    CERN Document Server

    Gersabeck, Marco

    2009-01-01

    LHCb will commence data taking as the first dedicated heavy flavour experiment at a hadron collider in 2008. A very high hit precision from its vertex detector (VELO) is essential to meet the tight requirements of vertex reconstruction in B-physics. The single hit precision of the VELO is better than 10 micron. However, the VELO is operated only 8 mm from the beam and must be retracted and reinserted each LHC fill. Hence, the detector places unique demands on its alignment algorithm. The partially assembled VELO system has already been tested in a beam test. The novel software alignment methods are presented together with their interplay with the metrology measurements. Results from Monte Carlo simulation studies are discussed and recent beam test results are shown that prove the method's precision at the micron level.

  17. Vertex Reconstruction and Performance in ATLAS

    CERN Document Server

    Whitmore, Ben William; The ATLAS collaboration

    2017-01-01

    Efficient and precise reconstruction of the primary vertices in LHC collisions is essential in both the reconstruction of the full kinematic properties of a hard-scatter event and of soft interactions as a measure of the amount of pile-up. The reconstruction of the primary vertices in the busy, high pile up environment of the LHC is a challenging task. The challenges and novel methods developed by the ATLAS experiment to reconstruct vertices in such environments will be presented. The performance of the current vertexing algorithms using Run-2 data will be presented and compared to results from simulation. Additionally, data-driven methods to evaluate vertex resolution, and details of upgrades to the ATLAS inner detector will be presented.

  18. Alignment strategy for the LHCb vertex locator

    CERN Document Server

    AUTHOR|(CDS)2075236

    2007-01-01

    LHCb is one of the four main experiments of the Large Hadron Collider (LHC) project, which will start at CERN in 2008. The experiment is primarily dedicated to B-Physics and hence requires precise vertex reconstruction. These requirements place strict constraints on the LHCb vertex locator (VELO) alignment. Additional challenges arise from the VELO being retracted between each fill of the LHC and from its unique circular disc R/$\\Phi$ strip geometry. This paper describes the software alignment procedure developed for the VELO, which is primarily based on a non-iterative method using a matrix inversion technique. The procedure is demonstrated with simulated events, and results obtained during runs in external test-beams are also presented.

  19. Primary vertex reconstruction with the ATLAS detector

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00286780

    2016-01-01

    Efficient and precise reconstruction of the primary vertex in a LHC collision is essential for determining the full kinematic properties of a hard-scatter event and of soft interactions as a measure of the amount of pile-up. The reconstruction of primary vertices in the busy, high pile-up environment of Run-2 of the LHC is a challenging task. The algorithms developed by the ATLAS experiments to reconstruct multiple vertices with small spatial separation are presented.

  20. The ZEUS vertex detector: Design and prototype

    International Nuclear Information System (INIS)

    Alvisi, C.; Anzivino, G.; Arzarello, F.; Barbagli, G.; Bari, G.; Basile, M.; Bellagamba, L.; Boscherini, D.; Bruni, G.; Bruni, P.; Camerini, U.; Cara Romeo, G.; Castellini, G.; Chiarini, M.; Cifarelli, L.; Cindolo, F.; Ciralli, F.; Contin, A.; Costa, M.; D'Auria, S.; Del Papa, C.; De Pasquale, S.; Fiori, F.; Forte, A.; Frasconi, F.; Giusti, P.; Iacobucci, G.; Laurenti, G.; Lisowski, B.; Maccarrone, G.; Margotti, A.; Massam, T.; Nania, R.; O'Shea, V.; Palmonari, F.; Pelfer, P.; Pilastrini, R.; Qian, S.; Sartorelli, G.; Schioppa, M.; Susinno, G.; Timellini, R.; Zichichi, A.; Bologna Univ.; Cosenza Univ.; Florence Univ.; Istituto Nazionale di Fisica Nucleare, Bologna; Istituto Nazionale di Fisica Nucleare, Florence; Istituto Nazionale di Fisica Nucleare, Frascati; Consiglio Nazionale delle Ricerche, Florence

    1991-01-01

    A gas vertex detector, operated with dimethylether (DME) at atmospheric pressure, is presently being built for the ZEUS experiment at HERA. Its main design features, together with the performances of a prototype measured at various operating voltages, particle rates and geometrical conditions on a CERN Proton Synchrotron test beam, are presented. A spatial resolution down to 35 μm and an average wire efficiency of 96% have been achieved, for a 3 mm gas gap relative to each sense wire. (orig.)

  1. Performance of the Belle silicon vertex detector

    CERN Document Server

    Hazumi, M

    2001-01-01

    The performance of the Silicon Vertex Detector (SVD) in the Belle experiment at the KEK B factory is described. The resolution on the distance between B meson vertices is estimated to be 115 sub - sub 2 sub 6 sup + sup 2 sup 4 mu m, which is good enough for the precise measurement of the CP asymmetry in B decays. A plan for the upgrade of the SVD is also mentioned.

  2. Complex growing networks with intrinsic vertex fitness

    International Nuclear Information System (INIS)

    Bedogne, C.; Rodgers, G. J.

    2006-01-01

    One of the major questions in complex network research is to identify the range of mechanisms by which a complex network can self organize into a scale-free state. In this paper we investigate the interplay between a fitness linking mechanism and both random and preferential attachment. In our models, each vertex is assigned a fitness x, drawn from a probability distribution ρ(x). In Model A, at each time step a vertex is added and joined to an existing vertex, selected at random, with probability p and an edge is introduced between vertices with fitnesses x and y, with a rate f(x,y), with probability 1-p. Model B differs from Model A in that, with probability p, edges are added with preferential attachment rather than randomly. The analysis of Model A shows that, for every fixed fitness x, the network's degree distribution decays exponentially. In Model B we recover instead a power-law degree distribution whose exponent depends only on p, and we show how this result can be generalized. The properties of a number of particular networks are examined

  3. Spin wave Feynman diagram vertex computation package

    Science.gov (United States)

    Price, Alexander; Javernick, Philip; Datta, Trinanjan

    Spin wave theory is a well-established theoretical technique that can correctly predict the physical behavior of ordered magnetic states. However, computing the effects of an interacting spin wave theory incorporating magnons involve a laborious by hand derivation of Feynman diagram vertices. The process is tedious and time consuming. Hence, to improve productivity and have another means to check the analytical calculations, we have devised a Feynman Diagram Vertex Computation package. In this talk, we will describe our research group's effort to implement a Mathematica based symbolic Feynman diagram vertex computation package that computes spin wave vertices. Utilizing the non-commutative algebra package NCAlgebra as an add-on to Mathematica, symbolic expressions for the Feynman diagram vertices of a Heisenberg quantum antiferromagnet are obtained. Our existing code reproduces the well-known expressions of a nearest neighbor square lattice Heisenberg model. We also discuss the case of a triangular lattice Heisenberg model where non collinear terms contribute to the vertex interactions.

  4. B Decay Charm Counting via Topological Vertexing

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Aaron S

    2001-10-15

    We present a new and unique measurement of the branching fractions of b hadrons to states with 0, 1, and 2 open charm hadrons, using a sample of 350,000 hadronic Z{sup 0} decays collected during the SLD/SLC 97-98 run. The method takes advantage of the excellent vertexing resolution of the VXD3, a pixel-based CCD vertex detector, which allows the separation of B and cascade D decay vertices. A fit of the vertex count and the decay length distributions to distribution shapes predicted by Monte Carlo simulation allows the extraction of the inclusive branching fractions. We measure: BR(B {yields} (0D)X) = (3.7{+-}1.1(stat) {+-} 2.1(syst))%; and BR(B {yields} (2D)X) = (17.9{+-}1.4(stat) {+-} 3.3(syst))% where B and D represent mixtures of open b and open c hadrons. The corresponding charm count, N{sub c} = 1.188 {+-} 0.010 {+-} 0.040 {+-} 0.006 is consistent with previous measurement averages but slightly closer to theoretical expectations.

  5. Prototyping the CBM Micro Vertex Detector

    Energy Technology Data Exchange (ETDEWEB)

    Koziel, Michal [University of Frankfurt, Frankfurt am Main (Germany); Collaboration: CBM-MVD-Collaboration

    2013-07-01

    For the reconstruction of Open Charm Hadrons with the CBM experiment a Micro Vertex Detector (MVD) with an excellent resolution of the secondary decay vertex (< 70 μm along the beam axis) is required. To achieve this vertex resolution a material budget of a few 0.1% X0 is mandatory for the individual detector stations positioned downstream in close vicinity to the target. To further reduce the multiple scattering the MVD operates in vacuum. The need of prototyping and characterizing the CBM-MVD motivated the construction of an advanced device - a beam telescope - giving the opportunity to exercise the following aspects: handling and integration of ultra-thin CMOS sensors on advanced materials like CVD diamond, double sided sensor assembly for ultra-precise tracking, cooling, scalable readout and slow control, development of data analysis framework and first steps towards implementation of tracking algorithms into a FPGA-based hardware. This group report aims to summarize the activity towards fabrication of the CBM-MVD prototype.

  6. Inflation and nonequilibrium renormalization group

    International Nuclear Information System (INIS)

    Zanella, Juan; Calzetta, Esteban

    2007-01-01

    We study the spectrum of primordial fluctuations and the scale dependence of the inflaton spectral index due to self-interactions of the field. We compute the spectrum of fluctuations by applying nonequilibrium renormalization group techniques

  7. Particle physics and QFT at the turn of the century: old principles with new concepts (an essay on local quantum physics)

    Energy Technology Data Exchange (ETDEWEB)

    Schroer, Bert [Frankfurt Univ. (Germany). Inst. fuer Theoretische Physik. E-mail: schroer@cbpf.br

    2000-04-01

    The present state of QFT is analyzed from a new viewpoint whose mathematical basis is the modular theory of von Neumann algebras. It physical consequences suggest new ways of dealing with interactions, symmetries, Hawking-Unruh thermal properties and possibly also extensions of the scheme of renormalized perturbation theory. Interactions are incorporated by using the fact that the S-matrix is a relative modular invariant of the interacting-relative to the incoming-net of wedge algebras. This new point of view allows many interesting comparisons with the standard quantization approach to QFT and is shown to be firmly rooted in the history of QFT. Its radical change of paradigm aspect becomes particularly visible in the quantum measurement problem. (author)

  8. Particle physics and QFT at the turn of the century: old principles with new concepts (an essay on local quantum physics))

    International Nuclear Information System (INIS)

    Schroer, Bert

    2000-04-01

    The present state of QFT is analyzed from a new viewpoint whose mathematical basis is the modular theory of von Neumann algebras. It physical consequences suggest new ways of dealing with interactions, symmetries, Hawking-Unruh thermal properties and possibly also extensions of the scheme of renormalized perturbation theory. Interactions are incorporated by using the fact that the S-matrix is a relative modular invariant of the interacting-relative to the incoming-net of wedge algebras. This new point of view allows many interesting comparisons with the standard quantization approach to QFT and is shown to be firmly rooted in the history of QFT. Its radical change of paradigm aspect becomes particularly visible in the quantum measurement problem. (author)

  9. Anisotropic nonequilibrium hydrodynamic attractor

    Science.gov (United States)

    Strickland, Michael; Noronha, Jorge; Denicol, Gabriel S.

    2018-02-01

    We determine the dynamical attractors associated with anisotropic hydrodynamics (aHydro) and the DNMR equations for a 0 +1 d conformal system using kinetic theory in the relaxation time approximation. We compare our results to the nonequilibrium attractor obtained from the exact solution of the 0 +1 d conformal Boltzmann equation, the Navier-Stokes theory, and the second-order Mueller-Israel-Stewart theory. We demonstrate that the aHydro attractor equation resums an infinite number of terms in the inverse Reynolds number. The resulting resummed aHydro attractor possesses a positive longitudinal-to-transverse pressure ratio and is virtually indistinguishable from the exact attractor. This suggests that an optimized hydrodynamic treatment of kinetic theory involves a resummation not only in gradients (Knudsen number) but also in the inverse Reynolds number. We also demonstrate that the DNMR result provides a better approximation of the exact kinetic theory attractor than the Mueller-Israel-Stewart theory. Finally, we introduce a new method for obtaining approximate aHydro equations which relies solely on an expansion in the inverse Reynolds number. We then carry this expansion out to the third order, and compare these third-order results to the exact kinetic theory solution.

  10. Tracking and Vertexing for the Heavy Photon Search Experiment

    Science.gov (United States)

    Uemura, Sho; HPS Collaboration

    2015-04-01

    The Heavy Photon Search (HPS) requires precision tracking and vertexing of e+e- pairs against a high background in a difficult experimental environment. The silicon vertex tracker (SVT) for HPS uses actively cooled silicon microstrip sensors with fast readout electronics. To maximize acceptance and vertex resolution with a relatively small detector, the SVT operates directly downstream of the target, close to the beam line, and inside of a dipole magnet. This talk presents the design and performance of the HPS SVT.

  11. Pion-nucleon vertex function with one nucleon off shell

    International Nuclear Information System (INIS)

    Mizutani, T.; Rochus, P.

    1979-01-01

    The pion-nucleon vertex function with an off-mass-shell nucleon is obtained through sideways dispersion relations with the P 11 and S 11 pion-nucleon phase shifts as only input. Contrary to the recent calculation of Nutt and Shakin, we find that the proper and improper vertex functions behave quite differently, indicating the importance of the nucleon propagator dressing. In particular the proper vertex function is found to have two poles in the unphysical region

  12. The Belle II Silicon Vertex Detector

    International Nuclear Information System (INIS)

    Friedl, M.; Ackermann, K.; Aihara, H.; Aziz, T.; Bergauer, T.; Bozek, A.; Campbell, A.; Dingfelder, J.; Drasal, Z.; Frankenberger, A.; Gadow, K.; Gfall, I.; Haba, J.; Hara, K.; Hara, T.; Higuchi, T.; Himori, S.; Irmler, C.; Ishikawa, A.; Joo, C.

    2013-01-01

    The KEKB machine and the Belle experiment in Tsukuba (Japan) are now undergoing an upgrade, leading to an ultimate luminosity of 8×10 35 cm −2 s −1 in order to measure rare decays in the B system with high statistics. The previous vertex detector cannot cope with this 40-fold increase of luminosity and thus needs to be replaced. Belle II will be equipped with a two-layer Pixel Detector surrounding the beam pipe, and four layers of double-sided silicon strip sensors at higher radii than the old detector. The Silicon Vertex Detector (SVD) will have a total sensitive area of 1.13m 2 and 223,744 channels—twice as many as its predecessor. All silicon sensors will be made from 150 mm wafers in order to maximize their size and thus to reduce the relative contribution of the support structure. The forward part has slanted sensors of trapezoidal shape to improve the measurement precision and to minimize the amount of material as seen by particles from the vertex. Fast-shaping front-end amplifiers will be used in conjunction with an online hit time reconstruction algorithm in order to reduce the occupancy to the level of a few percent at most. A novel “Origami” chip-on-sensor scheme is used to minimize both the distance between strips and amplifier (thus reducing the electronic noise) as well as the overall material budget. This report gives an overview on the status of the Belle II SVD and its components, including sensors, front-end detector ladders, mechanics, cooling and the readout electronics

  13. The Belle II Silicon Vertex Detector

    Energy Technology Data Exchange (ETDEWEB)

    Friedl, M., E-mail: markus.friedl@oeaw.ac.at [HEPHY – Institute of High Energy Physics, Nikolsdorfer Gasse 18, 1050 Vienna (Austria); Ackermann, K. [MPI Munich, Föhringer Ring 6, 80805 München (Germany); Aihara, H. [University of Tokyo, Department of Physics, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Aziz, T. [Tata Institute of Fundamental Research, Experimental High Energy Physics Group, Homi Bhabha Road, Mumbai 400 005 (India); Bergauer, T. [HEPHY – Institute of High Energy Physics, Nikolsdorfer Gasse 18, 1050 Vienna (Austria); Bozek, A. [Institute of Nuclear Physics, Division of Particle Physics and Astrophysics, ul. Radzikowskiego 152, 31 342 Krakow (Poland); Campbell, A. [DESY, Notkestrasse 85, 22607 Hamburg (Germany); Dingfelder, J. [University of Bonn, Department of Physics and Astronomy, Nussallee 12, 53115 Bonn (Germany); Drasal, Z. [Charles University, Institute of Particle and Nuclear Physics, Ke Karlovu 3, 121 16 Praha 2 (Czech Republic); Frankenberger, A. [HEPHY – Institute of High Energy Physics, Nikolsdorfer Gasse 18, 1050 Vienna (Austria); Gadow, K. [DESY, Notkestrasse 85, 22607 Hamburg (Germany); Gfall, I. [HEPHY – Institute of High Energy Physics, Nikolsdorfer Gasse 18, 1050 Vienna (Austria); Haba, J.; Hara, K.; Hara, T. [KEK, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Higuchi, T. [University of Tokyo, Kavli Institute for Physics and Mathematics of the Universe, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Himori, S. [Tohoku University, Department of Physics, Aoba Aramaki Aoba-ku, Sendai 980-8578 (Japan); Irmler, C. [HEPHY – Institute of High Energy Physics, Nikolsdorfer Gasse 18, 1050 Vienna (Austria); Ishikawa, A. [Tohoku University, Department of Physics, Aoba Aramaki Aoba-ku, Sendai 980-8578 (Japan); Joo, C. [Seoul National University, High Energy Physics Laboratory, 25-107 Shinlim-dong, Kwanak-gu, Seoul 151-742 (Korea, Republic of); and others

    2013-12-21

    The KEKB machine and the Belle experiment in Tsukuba (Japan) are now undergoing an upgrade, leading to an ultimate luminosity of 8×10{sup 35}cm{sup −2}s{sup −1} in order to measure rare decays in the B system with high statistics. The previous vertex detector cannot cope with this 40-fold increase of luminosity and thus needs to be replaced. Belle II will be equipped with a two-layer Pixel Detector surrounding the beam pipe, and four layers of double-sided silicon strip sensors at higher radii than the old detector. The Silicon Vertex Detector (SVD) will have a total sensitive area of 1.13m{sup 2} and 223,744 channels—twice as many as its predecessor. All silicon sensors will be made from 150 mm wafers in order to maximize their size and thus to reduce the relative contribution of the support structure. The forward part has slanted sensors of trapezoidal shape to improve the measurement precision and to minimize the amount of material as seen by particles from the vertex. Fast-shaping front-end amplifiers will be used in conjunction with an online hit time reconstruction algorithm in order to reduce the occupancy to the level of a few percent at most. A novel “Origami” chip-on-sensor scheme is used to minimize both the distance between strips and amplifier (thus reducing the electronic noise) as well as the overall material budget. This report gives an overview on the status of the Belle II SVD and its components, including sensors, front-end detector ladders, mechanics, cooling and the readout electronics.

  14. Elliptic genera and vertex operator super-algebras

    CERN Document Server

    Tamanoi, Hirotaka

    1999-01-01

    This monograph deals with two aspects of the theory of elliptic genus: its topological aspect involving elliptic functions, and its representation theoretic aspect involving vertex operator super-algebras. For the second aspect, elliptic genera are shown to have the structure of modules over certain vertex operator super-algebras. The vertex operators corresponding to parallel tensor fields on closed Riemannian Spin Kähler manifolds such as Riemannian tensors and Kähler forms are shown to give rise to Virasoro algebras and affine Lie algebras. This monograph is chiefly intended for topologists and it includes accounts on topics outside of topology such as vertex operator algebras.

  15. Finding and Counting Vertex-Colored Subtrees

    Science.gov (United States)

    Guillemot, Sylvain; Sikora, Florian

    The problems studied in this article originate from the Graph Motif problem introduced by Lacroix et al. [17] in the context of biological networks. The problem is to decide if a vertex-colored graph has a connected subgraph whose colors equal a given multiset of colors M. Using an algebraic framework recently introduced by Koutis et al. [15,16], we obtain new FPT algorithms for Graph Motif and variants, with improved running times. We also obtain results on the counting versions of this problem, showing that the counting problem is FPT if M is a set, but becomes # W [1]-hard if M is a multiset with two colors.

  16. Performance of the LHCb Vertex Locator

    CERN Document Server

    Latham, T

    2012-01-01

    LHCb is a dedicated flavour physics experiment at the Large Hadron Collider (LHC) at CERN. The Vertex Locator (VELO) is an essential part of the LHCb detector, permitting precision measurements of the production and decay vertices of beauty and charm particles. The VELO consists of a series of silicon micro-strip detectors, arranged in two retractable halves. Positioned only 7 mm from the beam during normal operations, it must withstand very high levels of radiation. The performance of the LHCb VELO during the first year of LHC physics running is presented.

  17. Developments in solid state vertex detectors

    International Nuclear Information System (INIS)

    Damerell, C.J.S.

    1984-12-01

    Since the discovery of the J/psi in November 1974, there has been a strong interest in the physics of particles containing higher-flavour quarks (charm, bottom, top, ...). High precision vertex detectors can be used to identify the decay products of parent particles which have lifetimes of the order 10 -13 s. The paper surveys the progress which is being made in developing silicon detectors with the necessary tracking precision (< approx. 5 μm) to be used for this purpose in fixed target experiments and also in colliders such as SLC and LEP. (author)

  18. The Mark II Vertex Drift Chamber

    International Nuclear Information System (INIS)

    Alexander, J.P.; Baggs, R.; Fujino, D.

    1989-03-01

    We have completed constructing and begun operating the Mark II Drift Chamber Vertex Detector. The chamber, based on a modified jet cell design, achieves 30 μm spatial resolution and 2 gas mixtures. Special emphasis has been placed on controlling systematic errors including the use of novel construction techniques which permit accurate wire placement. Chamber performance has been studied with cosmic ray tracks collected with the chamber located both inside and outside the Mark II. Results on spatial resolution, average pulse shape, and some properties of CO 2 mixtures are presented. 10 refs., 12 figs., 1 tab

  19. The Construction of Spin Foam Vertex Amplitudes

    Directory of Open Access Journals (Sweden)

    Eugenio Bianchi

    2013-01-01

    Full Text Available Spin foam vertex amplitudes are the key ingredient of spin foam models for quantum gravity. These fall into the realm of discretized path integral, and can be seen as generalized lattice gauge theories. They can be seen as an attempt at a 4-dimensional generalization of the Ponzano-Regge model for 3d quantum gravity. We motivate and review the construction of the vertex amplitudes of recent spin foam models, giving two different and complementary perspectives of this construction. The first proceeds by extracting geometric configurations from a topological theory of the BF type, and can be seen to be in the tradition of the work of Barrett, Crane, Freidel and Krasnov. The second keeps closer contact to the structure of Loop Quantum Gravity and tries to identify an appropriate set of constraints to define a Lorentz-invariant interaction of its quanta of space. This approach is in the tradition of the work of Smolin, Markopoulous, Engle, Pereira, Rovelli and Livine.

  20. First Results from the LHCb Vertex Locator

    CERN Multimedia

    Borghi, S

    2010-01-01

    LHCb is a dedicated experiment to study new physics in the decays of beauty and charm hadrons at the Large Hadron Collider (LHC) at CERN. The beauty and charm hadrons are identified through their flight distance in the Vertex Locator (VELO), and hence the detector is critical for both the trigger and offline physics analyses. The VELO is the silicon detector surrounding the interaction point, and is the closest LHC vertex detector to the interaction point, located only 7 mm from the LHC beam during normal operation. The detector will operate in an extreme and highly non-uniform radiation environment. The VELO consists of two retractable detector halves with 21 silicon micro-strip tracking modules each. A module is composed of two n+-on-n 300 micron thick half disc sensors with R-measuring and Phi-measuring micro-strip geometry, mounted on a carbon fibre support paddle. The minimum pitch is approximately 40 $\\mu$m. The detector is also equipped with one n-on-p module. The detectors are operated in vacuum and a...

  1. Speed Control of Pipeline Pig Using the QFT Method Contrôle de la vitesse d’un racleur grâce à la méthode de synthèse QFT

    Directory of Open Access Journals (Sweden)

    Mirshamsi M.

    2012-08-01

    Full Text Available To provide an efficient inspection of pipeline, pigging operations must be executed at a constant speed. This paper presents an efficient and simple method based on Quantitative Feedback Theory (QFT, which is a well-known robust controller scheme, for speed control of a pig with bypass flow in a liquid pipeline. This classical-type controller commands the valve installed in the body of the pig to open or close. Then, the pig is controlled using the amount of bypass flow across its body. For this purpose, the nonlinear dynamic equation of motion of the pig is converted to a family of linear uncertain equivalent plants using Sobhani-Rafeeyan’s method (SR method. Then, for this family of uncertain equivalent plants, a QFT-type controller is synthesized. The presented method is developed for two-dimensional pipelines in two cases. The designed controllers are simulated numerically using the Simulink toolbox of the MATLAB software. The simulation results show that the designed controller can be used for speed control of the pig with good performance when it runs in the liquid pipelines. Pour qu’une inspection de pipeline soit efficace, l’opération de raclage doit être réalisée à vitesse constante. Cet article présente une méthode simple et efficace fondée sur la théorie QFT (Quantitative Feedback Theory, système de régulation robuste bien connu, permettant de contrôler la vitesse d’un racleur avec bypass dans un oléoduc. Ce régulateur classique commande l’ouverture ou la fermeture d’une soupape installée sur le racleur. Le racleur est ensuite contrôlé grâce au volume de fluide qui le traverse. Pour cela, l’équation dynamique non linéaire du mouvement du racleur est convertie en un ensemble de structures linéaires instables équivalentes via la méthode Sobhani-Rafeeyan (méthode SR. Puis, un régulateur de type QFT est synthétisé. La méthode présentée est conçue pour des pipelines bidimensionnels dans deux

  2. Nonequilibrium thermodynamics of an interface

    Science.gov (United States)

    Schweizer, Marco; Öttinger, Hans Christian; Savin, Thierry

    2016-05-01

    Interfacial thermodynamics has deep ramifications in understanding the boundary conditions of transport theories. We present a formulation of local equilibrium for interfaces that extends the thermodynamics of the "dividing surface," as introduced by Gibbs, to nonequilibrium settings such as evaporation or condensation. By identifying the precise position of the dividing surface in the interfacial region with a gauge degree of freedom, we exploit gauge-invariance requirements to consistently define the intensive variables for the interface. The model is verified under stringent conditions by employing high-precision nonequilibrium molecular-dynamics simulations of a coexisting vapor-liquid Lennard-Jones fluid. We conclude that the interfacial temperature is determined using the surface tension as a "thermometer," and it can be significantly different from the temperatures of the adjacent phases. Our findings lay foundations for nonequilibrium interfacial thermodynamics.

  3. Non-equilibrium phase transitions

    CERN Document Server

    Henkel, Malte; Lübeck, Sven

    2009-01-01

    This book describes two main classes of non-equilibrium phase-transitions: (a) static and dynamics of transitions into an absorbing state, and (b) dynamical scaling in far-from-equilibrium relaxation behaviour and ageing. The first volume begins with an introductory chapter which recalls the main concepts of phase-transitions, set for the convenience of the reader in an equilibrium context. The extension to non-equilibrium systems is made by using directed percolation as the main paradigm of absorbing phase transitions and in view of the richness of the known results an entire chapter is devoted to it, including a discussion of recent experimental results. Scaling theories and a large set of both numerical and analytical methods for the study of non-equilibrium phase transitions are thoroughly discussed. The techniques used for directed percolation are then extended to other universality classes and many important results on model parameters are provided for easy reference.

  4. The Mark III vertex chamber and prototype test results

    International Nuclear Information System (INIS)

    Grab, C.

    1987-07-01

    A vertex chamber has been constructed for use in the Mark III experiment. The chamber is positioned inside the current main drift chamber and will be used to trigger data collection, to aid in vertex reconstruction, and to improve the momentum resolution. This paper discusses the chamber's construction and performance and tests of the prototype

  5. Fermionic construction of vertex operators for twisted affine algebras

    International Nuclear Information System (INIS)

    Frappat, L.; Sorba, P.; Sciarrino, A.

    1988-03-01

    We construct vertex operator representations of the twisted affine algebras in terms of fermionic (or parafermionic in some cases) elementary fields. The folding method applied to the extended Dynkin diagrams of the affine algebras allows us to determine explicitly these fermionic fields as vertex operators

  6. Graphs with No Induced Five-Vertex Path or Antipath

    DEFF Research Database (Denmark)

    Chudnovsky, Maria; Esperet, Louis; Lemoine, Laetitia

    2017-01-01

    We prove that a graph G contains no induced five-vertex path and no induced complement of a five-vertex path if and only if G is obtained from 5-cycles and split graphs by repeatedly applying the following operations: substitution, split unification, and split unification in the complement, where...

  7. Design of a secondary-vertex trigger system

    International Nuclear Information System (INIS)

    Husby, D.; Chew, P.; Sterner, K.; Selove, W.

    1995-06-01

    For the selection of beauty and charm events with high efficiency at the Tevatron, a secondary-vertex trigger system is under design. It would operate on forward-geometry events. The system would use on-line tracking of all tracks in the vertex detector, to identify events with clearly detached secondary vertices

  8. Vertex epidural haematoma manifesting with bilateral upper limb ...

    African Journals Online (AJOL)

    Vertex epidural haematomas (VEDH) are rare and difficulties are encountered in diagnosis and management. This is a case report of a patient with a vertex epidural haematoma who presented with signs of severe head injury with upper limb decerebrate posture. We discuss the challenges of radiological investigation and ...

  9. Drift chamber vertex detectors for SLC/LEP

    International Nuclear Information System (INIS)

    Hayes, K.G.

    1987-03-01

    The short but measurable lifetimes of the b and c quarks and the tau lepton have motivated the development of high precision tracking detectors capable of providing information on the decay vertex topology of events containing these particles. This paper reviews the OPAL, L3, and MARK II experiments vertex drift chambers

  10. Vertex Accentuation in Female Pattern Hair Loss in Asians

    Directory of Open Access Journals (Sweden)

    Chavalit Supsrisunjai

    2016-05-01

    Full Text Available Background: The most common cause of hair loss seen in women is female pattern hair loss (FPHL, also known as female androgenetic alopecia. It affects the central part of the scalp, but spares the frontal hairline. Frontal accentuation was also described by Olsen. In Asian women, vertex thinning patterns are frequently developed, but there has been no report about vertex thinning pattern in female pattern hair loss. Objective: To find prevalence of vertex accentuation in female pattern hair loss (FPHL in Asian women. Methods: Scalp hair counting (n/cm2 were measured at 3 different areas; vertex, mid scalp and frontal area respectively by digital dermoscope (Dino digital AM-413T. Visual counting and photography were performed. Outcomes were evaluated by gross appearance of vertex thinning and/or hair density <120 /cm2 in any of 3 areas. Results: 143 patients were evaluated. Mean age was 45.54 years. Of the hair loss type, 36.4% were mid-scalp, 33.6% were vertex accentuation and 30.1% were frontal accentuation, respectively. Age was not significantly different among the 3 types of hair loss (P- value 0.859. Conclusion: Although the most common female pattern hair loss type is diffuse type (Ludwig type, vertex accentuation pattern is the second most common pattern in this study. This study is the first to mention “Vertex accentuation” to be another pattern for FPHL.

  11. Genus Ranges of 4-Regular Rigid Vertex Graphs.

    Science.gov (United States)

    Buck, Dorothy; Dolzhenko, Egor; Jonoska, Nataša; Saito, Masahico; Valencia, Karin

    2015-01-01

    A rigid vertex of a graph is one that has a prescribed cyclic order of its incident edges. We study orientable genus ranges of 4-regular rigid vertex graphs. The (orientable) genus range is a set of genera values over all orientable surfaces into which a graph is embedded cellularly, and the embeddings of rigid vertex graphs are required to preserve the prescribed cyclic order of incident edges at every vertex. The genus ranges of 4-regular rigid vertex graphs are sets of consecutive integers, and we address two questions: which intervals of integers appear as genus ranges of such graphs, and what types of graphs realize a given genus range. For graphs with 2 n vertices ( n > 1), we prove that all intervals [ a, b ] for all a genus ranges. For graphs with 2 n - 1 vertices ( n ≥ 1), we prove that all intervals [ a, b ] for all a genus ranges. We also provide constructions of graphs that realize these ranges.

  12. Twisted vertex algebras, bicharacter construction and boson-fermion correspondences

    International Nuclear Information System (INIS)

    Anguelova, Iana I.

    2013-01-01

    The boson-fermion correspondences are an important phenomena on the intersection of several areas in mathematical physics: representation theory, vertex algebras and conformal field theory, integrable systems, number theory, cohomology. Two such correspondences are well known: the types A and B (and their super extensions). As a main result of this paper we present a new boson-fermion correspondence of type D-A. Further, we define a new concept of twisted vertex algebra of order N, which generalizes super vertex algebra. We develop the bicharacter construction which we use for constructing classes of examples of twisted vertex algebras, as well as for deriving formulas for the operator product expansions, analytic continuations, and normal ordered products. By using the underlying Hopf algebra structure we prove general bicharacter formulas for the vacuum expectation values for two important groups of examples. We show that the correspondences of types B, C, and D-A are isomorphisms of twisted vertex algebras

  13. CMB and the elementary particles structure deduced from QFT of non-dot model

    Science.gov (United States)

    Chen, Shao-Guang

    In my paper ‘Planck Constant Deduced from Metrical Results of Doppler Effect of Moving Particle —Uncertainty Principle Caused by Collision of a Particle with CMB Photons and Virtual Photons (H05-0036-10)’ the absolute velocity is decided by CMB which as a mark of the vacuum. CMB come from the thermal radiation of stars via gravitational redshift about 10 (13) year (E14- 0032-08). In my paper ‘Quanta turn-advance ism, China Science && Technology Overview 131 192-210 (2011)’, QFT four-dimensional uncertainty principle and momentum-energy conservation law had been generalized as a five-dimensional equations: de Broglie wavelength as a position vector \\underline{q}= (i c t, r, s), momentum \\underline{P} = (i E / c, P, U c), \\underline{q} = i h / \\underline{P}, \\underline{q} \\underline{q} = 0, \\underline{P} \\underline{P} = 0, Sigma∑ \\underline{P} = \\underline{P} (0) . The five-dimensional time-space-spin had been quantized as a non-dot model basic cell, the lowest energy state vertical polarized left spin 1/2 neutrino and right spin 1/2 antineutrino are just the left, right advance unit quanta _{0}nuυ, nuυ _{0} and left, right back unit quanta (0) nuυ, nuυ (0) , it again compose into spin 1 unit advance photons _{0}nuυnuυ _{0} and back (0) nuυnuυ (0) , spin 0 unit rest mass nuυ _{0}nuυ (0) and anti-mass _{0}nuυ (0) nuυ, spin 0 unit positive charge _{0}nuυnuυ (0) and negative charge nuυ _{0} (0) nuυ. It accord to the high energy physics experimental results of the transformation among the photons, masses quanta and charges quanta. The physical vacuum is the even collocation of non-combinational nuυ _{0} or _{0}nuυ. QFT is no longer with divergence difficulty by the non-dot model. It is mathematically easy that from five-dimensional equations deduce out the Dirac, Klein-Gordan, Maxwell equations and Lorentz force formula, but appear some new results. The interactions between _{0}nuυ, nuυ _{0}, (0) nuυ, nuυ (0) , i.e., force f

  14. Open problems in non-equilibrium physics

    Energy Technology Data Exchange (ETDEWEB)

    Kusnezov, D.

    1997-09-22

    The report contains viewgraphs on the following: approaches to non-equilibrium statistical mechanics; classical and quantum processes in chaotic environments; classical fields in non-equilibrium situations: real time dynamics at finite temperature; and phase transitions in non-equilibrium conditions.

  15. Primary Vertex Reconstruction for Upgrade at LHCb

    CERN Document Server

    Wanczyk, Joanna

    2016-01-01

    The aim of the LHCb experiment is the study of beauty and charm hadron decays with the main focus on CP violating phenomena and searches for physics beyond the Standard Model through rare decays. At the present, the second data taking period is ongoing, which is called Run II. After 2018 during the long shutdown, the replacement of signicant parts of the LHCb detector is planned. One of main changes is upgrade of the present software and hardware trigger to a more rapid full software trigger. Primary Vertex (PV) is a basis for the further tracking and it is sensitive to the LHC running conditions, which are going to change for the Upgrade. In particular, the center-of-mass collision energy should reach the maximum value of 14 TeV. As a result the quality of the reconstruction has to be studied and the reconstruction algorithms have to be optimized.

  16. Resistance Distances in Vertex-Face Graphs

    Science.gov (United States)

    Shangguan, Yingmin; Chen, Haiyan

    2018-01-01

    The computation of two-point resistances in networks is a classical problem in electric circuit theory and graph theory. Let G be a triangulation graph with n vertices embedded on an orientable surface. Define K(G) to be the graph obtained from G by inserting a new vertex vϕ to each face ϕ of G and adding three new edges (u, vϕ), (v, vϕ) and (w, vϕ), where u, v and w are three vertices on the boundary of ϕ. In this paper, using star-triangle transformation and resistance local-sum rules, explicit relations between resistance distances in K(G) and those in G are obtained. These relations enable us to compute resistance distance between any two points of Kk(G) recursively. As explanation examples, some resistances in several networks are computed, including the modified Apollonian network and networks constructed from tetrahedron, octahedron and icosahedron, respectively.

  17. The PHENIX Forward Silicon Vertex Detector

    International Nuclear Information System (INIS)

    Aidala, C.; Anaya, L.; Anderssen, E.; Bambaugh, A.; Barron, A.; Boissevain, J.G.; Bok, J.; Boose, S.; Brooks, M.L.; Butsyk, S.; Cepeda, M.; Chacon, P.; Chacon, S.; Chavez, L.; Cote, T.; D'Agostino, C.; Datta, A.; DeBlasio, K.; DelMonte, L.; Desmond, E.J.

    2014-01-01

    A new silicon detector has been developed to provide the PHENIX experiment with precise charged particle tracking at forward and backward rapidity. The Forward Silicon Vertex Tracker (FVTX) was installed in PHENIX prior to the 2012 run period of the Relativistic Heavy Ion Collider (RHIC). The FVTX is composed of two annular endcaps, each with four stations of silicon mini-strip sensors, covering a rapidity range of 1.2<|η|<2.2 that closely matches the two existing PHENIX muon arms. Each station consists of 48 individual silicon sensors, each of which contains two columns of mini-strips with 75 μm pitch in the radial direction and lengths in the ϕ direction varying from 3.4 mm at the inner radius to 11.5 mm at the outer radius. The FVTX has approximately 0.54 million strips in each endcap. These are read out with FPHX chips, developed in collaboration with Fermilab, which are wire bonded directly to the mini-strips. The maximum strip occupancy reached in central Au–Au collisions is approximately 2.8%. The precision tracking provided by this device makes the identification of muons from secondary vertices away from the primary event vertex possible. The expected distance of closest approach (DCA) resolution of 200 μm or better for particles with a transverse momentum of 5 GeV/c will allow identification of muons from relatively long-lived particles, such as D and B mesons, through their broader DCA distributions

  18. Computer simulation of nonequilibrium processes

    International Nuclear Information System (INIS)

    Hoover, W.G.; Moran, B.; Holian, B.L.; Posch, H.A.; Bestiale, S.

    1987-01-01

    Recent atomistic simulations of irreversible macroscopic hydrodynamic flows are illustrated. An extension of Nose's reversible atomistic mechanics makes it possible to simulate such non-equilibrium systems with completely reversible equations of motion. The new techniques show that macroscopic irreversibility is a natural inevitable consequence of time-reversible Lyapunov-unstable microscopic equations of motion

  19. Non-equilibrium supramolecular polymerization.

    Science.gov (United States)

    Sorrenti, Alessandro; Leira-Iglesias, Jorge; Markvoort, Albert J; de Greef, Tom F A; Hermans, Thomas M

    2017-09-18

    Supramolecular polymerization has been traditionally focused on the thermodynamic equilibrium state, where one-dimensional assemblies reside at the global minimum of the Gibbs free energy. The pathway and rate to reach the equilibrium state are irrelevant, and the resulting assemblies remain unchanged over time. In the past decade, the focus has shifted to kinetically trapped (non-dissipative non-equilibrium) structures that heavily depend on the method of preparation (i.e., pathway complexity), and where the assembly rates are of key importance. Kinetic models have greatly improved our understanding of competing pathways, and shown how to steer supramolecular polymerization in the desired direction (i.e., pathway selection). The most recent innovation in the field relies on energy or mass input that is dissipated to keep the system away from the thermodynamic equilibrium (or from other non-dissipative states). This tutorial review aims to provide the reader with a set of tools to identify different types of self-assembled states that have been explored so far. In particular, we aim to clarify the often unclear use of the term "non-equilibrium self-assembly" by subdividing systems into dissipative, and non-dissipative non-equilibrium states. Examples are given for each of the states, with a focus on non-dissipative non-equilibrium states found in one-dimensional supramolecular polymerization.

  20. Rheology via nonequilibrium molecular dynamics

    International Nuclear Information System (INIS)

    Hoover, W.G.

    1982-10-01

    The equilibrium molecular dynamics formulated by Newton, Lagrange, and Hamilton has been modified in order to simulate rheologial molecular flows with fast computers. This modified Nonequilibrium Molecular Dynamics (NEMD) has been applied to fluid and solid deformations, under both homogeneous and shock conditions, as well as to the transport of heat. The irreversible heating associated with dissipation could be controlled by carrying out isothermal NEMD calculations. The new isothermal NEMD equations of motion are consistent with Gauss' 1829 Least-Constraint principle as well as certain microscopic equilibrium and nonequilibrium statistical formulations due to Gibbs and Boltzmann. Application of isothermal NEMD revealed high-frequency and high-strain-rate behavior for simple fluids which resembled the behavior of polymer solutions and melts at lower frequencies and strain rates. For solids NEMD produces plastic flows consistent with experimental observations at much lower strain rates. The new nonequilibrium methods also suggest novel formulations of thermodynamics in nonequilibrium systems and shed light on the failure of the Principle of Material Frame Indifference

  1. B and c quark exclusive decays with the vertex detector

    International Nuclear Information System (INIS)

    Hayes, K.

    1987-01-01

    Physics topics as diverse as the forward backward charge asymmetry to CP violation can be studied with the aid of heavy quark exclusive decays at the Z 0 . The Mark II with its vertex detector is sufficiently powerful to do a good job on many of these topics with reasonable acceptances and sample purities. Measurements of the absolute value of V/sub bu/ using B 0 → π + π - and of the B 0 lifetime using the decay B 0 → D + + l - + neutrals (D + → K - π + π + ) have been illustrated in this paper. Unfortunately, given the small branching ratios for most exclusive decay modes, large numbers of Z 0 decays are needed. From the standpoint of vertex detector performance, the Mark II vertex detector can fully reconstruct the vertex topology of nearly all strange particle decays, but in general can only tag the presence of secondary b and c quark decay vertices with good efficiency. High efficiency full vertex reconstruction of heavy quark decays requires an order of magnitude improvement in impact parameter resolution. Analyses which use vertex detector information to make vertex topology cuts for b and c quark decay will have good efficiency if significant impact parameters (δ/σ > 3) are required for only a few tracks. 7 references, 6 figures

  2. Vertex operators, virasoro conditions and string dynamics in curved space

    International Nuclear Information System (INIS)

    Wadia, S.R.

    1987-01-01

    String propagation in a background metric and dilation field are considered in the context of conformal invariant field theory. A perturbatively renormalized tachyon vertex in the presence of these background fields is presented. This generalises the Berezinsky-Kosterlitz-Thouless construction. The equations of motion for the background fields and the wave equation for the vertex function emerge upon imposing the Virasoro gauge conditions on the vertex operator. This is equivalent to calculating the equation of motion Qvertical barpsi> = 0 in the BRST approach

  3. Self-dual vertex operator superalgebras and superconformal field theory

    Science.gov (United States)

    Creutzig, Thomas; Duncan, John F. R.; Riedler, Wolfgang

    2018-01-01

    Recent work has related the equivariant elliptic genera of sigma models with K3 surface target to a vertex operator superalgebra that realizes moonshine for Conway’s group. Motivated by this we consider conditions under which a self-dual vertex operator superalgebra may be identified with the bulk Hilbert space of a superconformal field theory. After presenting a classification result for self-dual vertex operator superalgebras with central charge up to 12 we describe several examples of close relationships with bulk superconformal field theories, including those arising from sigma models for tori and K3 surfaces.

  4. LHCb VELO Closing Control, Vertex Resolution and Luminosity Measurement

    CERN Document Server

    Redford, S

    2010-01-01

    The LHCb Vertex Locator (VELO) surrounds the collision point at IP8 of the LHC ring and performs precise tracking and vertexing. This silicon micro-strip detector is built in two halves, which each move independently in the transverse plane so as to approach the collision region during data taking, but retract whilst the beams are injected and adjusted. The closing procedure of the VELO is detailed, along with an analysis of the primary vertex resolution and a description of the role of the VELO in the LHCb luminosity measurement.

  5. Nonequilibrium quantum fluctuations of work.

    Science.gov (United States)

    Allahverdyan, A E

    2014-09-01

    The concept of work is basic for statistical thermodynamics. To gain a fuller understanding of work and its (quantum) features, it needs to be represented as an average of a fluctuating quantity. Here I focus on the work done between two moments of time for a thermally isolated quantum system driven by a time-dependent Hamiltonian. I formulate two natural conditions needed for the fluctuating work to be physically meaningful for a system that starts its evolution from a nonequilibrium state. The existing definitions do not satisfy these conditions due to issues that are traced back to noncommutativity. I propose a definition of fluctuating work that is free of previous drawbacks and that applies for a wide class of nonequilibrium initial states. It allows the deduction of a generalized work-fluctuation theorem that applies for an arbitrary (out-of-equilibrium) initial state.

  6. Computer simulation of nonequilibrium processes

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, D.C.

    1985-07-01

    The underlying concepts of nonequilibrium statistical mechanics, and of irreversible thermodynamics, will be described. The question at hand is then, how are these concepts to be realize in computer simulations of many-particle systems. The answer will be given for dissipative deformation processes in solids, on three hierarchical levels: heterogeneous plastic flow, dislocation dynamics, an molecular dynamics. Aplication to the shock process will be discussed.

  7. 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.

  8. Graph Theory. 2. Vertex Descriptors and Graph Coloring

    Directory of Open Access Journals (Sweden)

    Lorentz JÄNTSCHI

    2002-12-01

    Full Text Available This original work presents the construction of a set of ten sequence matrices and their applications for ordering vertices in graphs. For every sequence matrix three ordering criteria are applied: lexicographic ordering, based on strings of numbers, corresponding to every vertex, extracted as rows from sequence matrices; ordering by the sum of path lengths from a given vertex; and ordering by the sum of paths, starting from a given vertex. We also examine a graph that has different orderings for the above criteria. We then proceed to demonstrate that every criterion induced its own partition of graph vertex. We propose the following theoretical result: both LAVS and LVDS criteria generate identical partitioning of vertices in any graph. Finally, a coloring of graph vertices according to introduced ordering criteria was proposed.

  9. Assembling the last module of the vertex locator for LHCb

    CERN Multimedia

    Maximilien Brice

    2007-01-01

    The 42nd and final vertex locator module is assembled in the LHCb clean room. This will be used to measure the point at which two protons in the beam collide from the tracks of particles produced in the collision.

  10. Vertex models: from cell mechanics to tissue morphogenesis.

    Science.gov (United States)

    Alt, Silvanus; Ganguly, Poulami; Salbreux, Guillaume

    2017-05-19

    Tissue morphogenesis requires the collective, coordinated motion and deformation of a large number of cells. Vertex model simulations for tissue mechanics have been developed to bridge the scales between force generation at the cellular level and tissue deformation and flows. We review here various formulations of vertex models that have been proposed for describing tissues in two and three dimensions. We discuss a generic formulation using a virtual work differential, and we review applications of vertex models to biological morphogenetic processes. We also highlight recent efforts to obtain continuum theories of tissue mechanics, which are effective, coarse-grained descriptions of vertex models.This article is part of the themed issue 'Systems morphodynamics: understanding the development of tissue hardware'. © 2017 The Authors.

  11. Performance of the LHCb Vertex Locator

    CERN Document Server

    Aaij, R.; Akiba, K.; Alexander, M.; Ali, S.; Appleby, R.B.; Artuso, M.; Bates, A.; Bay, A.; Behrendt, O.; Benton, J.; van Beuzekom, M.; Bjornstad, P.M.; Bogdanova, G.; Borghi, S.; Borgia, A.; Bowcock, T.J.V.; van den Brand, J.; Brown, H.; Buytaert, J.; Callot, O.; Carroll, J.; Casse, G.; Collins, P.; De Capua, S.; Doets, M.; Donleavy, S.; Dossett, D.; Dumps, R.; Eckstein, D.; Eklund, L.; Farinelli, C.; Farry, S.; Ferro-Luzzi, M.; Frei, R.; Garofoli, J.; Gersabeck, M.; Gershon, T.; Gong, A.; Gong, H.; Gordon, H.; Haefeli, G.; Harrison, J.; Heijne, V.; Hennessy, K.; Hulsbergen, W.; Huse, T.; Hutchcroft, D.; Jaeger, A.; Jalocha, P.; Jans, E.; John, M.; Keaveney, J.; Ketel, T.; Korolev, M.; Kraan, M.; Lastovicka, T.; Lafferty, G.; Latham, T.; Lefeuvre, G.; Leflat, A.; Liles, M.; van Lysebetten, A.; MacGregor, G.; Marinho, F.; McNulty, R.; Merkin, M.; Moran, D.; Mountain, R.; Mous, I.; Mylroie-Smith, J.; Needham, M.; Nikitin, N.; Noor, A.; Oblakowska-Mucha, A.; Papadelis, A.; Pappagallo, M.; Parkes, C.; Patel, G.D.; Rakotomiaramanana, B.; Redford, S.; Reid, M.; Rinnert, K.; Rodrigues, E.; Saavedra, A.F.; Schiller, M.; Schneider, O.; Shears, T.; Silva Coutinho, R.; Smith, N.A.; Szumlak, T.; Thomas, C.; van Tilburg, J.; Tobin, M.; Velthuis, J.; Verlaat, B.; Viret, S.; Volkov, V.; Wallace, C.; Wang, J.; Webber, A.; Whitehead, M.; Zverev, E.

    2014-01-01

    The Vertex Locator (VELO) is a silicon microstrip detector that surrounds the proton-proton interaction region in the LHCb experiment. The performance of the detector during the first years of its physics operation is reviewed. The system is operated in vacuum, uses a bi-phase CO2 cooling system, and the sensors are moved to 7 mm from the LHC beam for physics data taking. The performance and stability of these characteristic features of the detector are described, and details of the material budget are given. The calibration of the timing and the data processing algorithms that are implemented in FPGAs are described. The system performance is fully characterised. The sensors have a signal to noise ratio of approximately 20 and a best hit resolution of 4 microns is achieved at the optimal track angle. The typical detector occupancy for minimum bias events in standard operating conditions in 2011 is around 0.5%, and the detector has less than 1% of faulty strips. The proximity of the detector to the beam means ...

  12. Performance of the LHCb Vertex Locator

    CERN Document Server

    van Beuzekom, Martin

    2012-01-01

    LHCb is a dedicated experiment to study new physics in the decays of beauty and charm hadrons at the Large Hadron Collider (LHC) at CERN. The beauty and charm hadrons are identified through their flight distance in the Vertex Locator (VELO), and hence the detector is essential for both the trigger and physics analyses. The VELO is the silicon micro- strip detector surrounding the LHCb interaction point, and is located only 8 mm from the LHC beam during normal operation. It consists of two retractable detector halves with 21 silicon micro-strip tracking modules each and is moved into position for each fill of the LHC, once stable beams are obtained. The detector operates in an extreme and highly non-uniform radiation environment, and the effects of surface and bulk radiation damage have already been measured. The VELO has been successfully operated for the first LHC physics run. Operational results show a signal to noise ratio of > 17 and a cluster finding efficiency of 99.5%. The small pitch a...

  13. Linear Time Vertex Partitioning on Massive Graphs

    Science.gov (United States)

    Mell, Peter; Harang, Richard; Gueye, Assane

    2016-01-01

    The problem of optimally removing a set of vertices from a graph to minimize the size of the largest resultant component is known to be NP-complete. Prior work has provided near optimal heuristics with a high time complexity that function on up to hundreds of nodes and less optimal but faster techniques that function on up to thousands of nodes. In this work, we analyze how to perform vertex partitioning on massive graphs of tens of millions of nodes. We use a previously known and very simple heuristic technique: iteratively removing the node of largest degree and all of its edges. This approach has an apparent quadratic complexity since, upon removal of a node and adjoining set of edges, the node degree calculations must be updated prior to choosing the next node. However, we describe a linear time complexity solution using an array whose indices map to node degree and whose values are hash tables indicating the presence or absence of a node at that degree value. This approach also has a linear growth with respect to memory usage which is surprising since we lowered the time complexity from quadratic to linear. We empirically demonstrate linear scalability and linear memory usage on random graphs of up to 15000 nodes. We then demonstrate tractability on massive graphs through execution on a graph with 34 million nodes representing Internet wide router connectivity. PMID:27336059

  14. Performance of the ATLAS primary vertex reconstruction algorithms

    CERN Document Server

    Zhang, Matt

    2017-01-01

    The reconstruction of primary vertices in the busy, high pile up environment of the LHC is a challenging task. The challenges and novel methods developed by the ATLAS experiment to reconstruct vertices in such environments will be presented. Such advances in vertex seeding include methods taken from medical imagining, which allow for reconstruction of very nearby vertices will be highlighted. The performance of the current vertexing algorithms using early Run-2 data will be presented and compared to results from simulation.

  15. R&D Challenges of a CLIC Vertex Detector

    CERN Document Server

    van der Kraaij, E

    2010-01-01

    The Compact Linear Collider (CLIC) is a concept for an electron-positron collider with a center- of-mass energy of up to 3 TeV. Given the unprecedented experimental conditions at CLIC none of the technologies available today can fulfill all requirements set for the vertex detector. At the conference these conditions and the challenges they pose for the R&D of a CLIC vertex detector were presented.

  16. The quintic interaction vertex in light-cone gravity

    International Nuclear Information System (INIS)

    Ananth, Sudarshan

    2008-01-01

    We consider pure gravity in light-cone gauge and derive the complete quintic interaction vertex. Up to quartic order, the Kawai-Lewellen-Tye (KLT) relations can be made manifest at the level of the Einstein-Hilbert Lagrangian. The quintic interaction vertex represents an essential first step in further extending the off-shell validity of the KLT relations to higher order vertices

  17. The vertex detector for the Lepton/Photon collaboration

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, J.P.; Boissevain, J.G.; Fox, D.; Hecke, H. van; Jacak, B.V.; Kapustinsky, J.S.; Leitch, M.J.; McGaughey, P.L.; Moss, J.M.; Sondheim, W.E. [Los Alamos National Lab., NM (United States)

    1991-12-31

    The conceptual design of the vertex detector for the Lepton/Photon Collaboration at RHIC is described, including simulations of its expected performance. The design consists of two con- centric layers of single-sided Si strips. The expected performance as a multiplicity detector and in measuring the pseudo-rapidity ({nu}) distribution is discussed as well as the expected vertex finding efficiency and accuracy. Various options which could be used to reduce the cost of the detector are also discussed.

  18. Mirror of the refined topological vertex from a matrix model

    CERN Document Server

    Eynard, B

    2011-01-01

    We find an explicit matrix model computing the refined topological vertex, starting from its representation in terms of plane partitions. We then find the spectral curve of that matrix model, and thus the mirror symmetry of the refined vertex. With the same method we also find a matrix model for the strip geometry, and we find its mirror curve. The fact that there is a matrix model shows that the refined topological string amplitudes also satisfy the remodeling the B-model construction.

  19. Relations for Modular Forms from Vertex Operator Algebras

    Science.gov (United States)

    Zuevsky, Alexander

    2018-02-01

    We will give a short reminder for vertex operator algebra notion and corresponding characters. Then we discuss algebraic methods for explicit computation of the partition and correlation functions. We then illustrate general ways to find number theory identities for related modular forms by specific examples of modular form relations arising from our construction. Finally, we present new results concerning identities for prime forms on genus g Riemann surfaces and genus two n-point functions for vertex operator algebra characters.

  20. The vertex detector for the Lepton/Photon Collaboration

    International Nuclear Information System (INIS)

    Sullivan, J.P.; Boissevain, J.G.; Fox, D.; van Hecke, H.; Jacak, B.V.; Kapustinsky, J.S.; Leitch, M.J.; McGaughey, P.L.; Moss, J.M.; Sondheim, W.E.

    1991-01-01

    The conceptual design of the vertex detector for the Lepton/Photon Collaboration at RHIC is described, including simulations of its expected performance. The design consists of two concentric layers of single-sided Si strips. The expected performance as a multiplicity detector and in measuring the pseudo-rapidity η distribution is discussed as well as the expected vertex finding efficiency and accuracy. Various options which could be used to reduce the cost of the detector are also discussed

  1. Vertex Reconstruction at STAR: Overview and Performance Evaluation

    Science.gov (United States)

    Smirnov, D.; Lauret, J.; Perevoztchikov, V.; Van Buren, G.; Webb, J.

    2017-10-01

    The STAR experiment at the Relativistic Heavy Ion Collider (RHIC) has a rich physics program ranging from studies of the Quark Gluon Plasma to the exploration of the spin structure of the proton. Many measurements carried out by the STAR collaboration rely on the efficient reconstruction and precise knowledge of the position of the primary-interaction vertex. Throughout the years two main vertex finders have been predominantly utilized in event reconstruction by the experiment: MinutVF and PPV with their application domains focusing on heavy ion and proton-proton events respectively. In this work we give a brief overview and discuss recent improvements to the vertex finding algorithms implemented in the STAR software library. In our studies we focus on the finding efficiency and the quality of the reconstructed primary vertex. We examine the effect of an additional constraint, imposed by an independent measurement of the beam line position, when it is applied during the fit. We evaluate the significance of the improved primary vertex resolution on identification of the secondary decay vertices occurring inside the beam pipe. Finally, we present a method and its software implementation developed to measure the performance of the primary vertex reconstruction algorithms.

  2. Gauge-invariant three-gluon vertex in QCD

    International Nuclear Information System (INIS)

    Cornwall, J.M.; Papavassiliou, J.

    1989-01-01

    By resumming the Feynman graphs which contribute to any gauge-invariant process we explicitly construct, at one-loop order, a three-gluon vertex for QCD which is completely independent of the choice of gauge. This vertex satisfies a Ward identity of the type encountered in ghost-free gauges, relating the vertex to the proper self-energy of a previously constructed gluon propagator, also found by resumming graphs; like the vertex, this self-energy is completely gauge invariant. We also derive the gauge-invariant propagator and vertex via a second related technique which minimizes the dependence on embedding these objects in a gauge-invariant process; the same results are found as in the first technique. These results motivate a toy model of the nonlinear Schwinger-Dyson equation satisfied by the exact gauge-invariant three-gluon vertex. This model is nonperturbative and has infrared singularities, which we can remove via gluon mass generation; it shows many interesting features expected of QCD, such as a β function which is not Borel summable in perturbation theory

  3. Loop Shaping Control Design for a Supersonic Propulsion System Model Using Quantitative Feedback Theory (QFT) Specifications and Bounds

    Science.gov (United States)

    Connolly, Joseph W.; Kopasakis, George

    2010-01-01

    This paper covers the propulsion system component modeling and controls development of an integrated mixed compression inlet and turbojet engine that will be used for an overall vehicle Aero-Propulso-Servo-Elastic (APSE) model. Using previously created nonlinear component-level propulsion system models, a linear integrated propulsion system model and loop shaping control design have been developed. The design includes both inlet normal shock position control and jet engine rotor speed control for a potential supersonic commercial transport. A preliminary investigation of the impacts of the aero-elastic effects on the incoming flow field to the propulsion system are discussed, however, the focus here is on developing a methodology for the propulsion controls design that prevents unstart in the inlet and minimizes the thrust oscillation experienced by the vehicle. Quantitative Feedback Theory (QFT) specifications and bounds, and aspects of classical loop shaping are used in the control design process. Model uncertainty is incorporated in the design to address possible error in the system identification mapping of the nonlinear component models into the integrated linear model.

  4. Manipulating nonequilibrium magnetism through superconductors.

    Science.gov (United States)

    Giazotto, Francesco; Taddei, Fabio; Fazio, Rosario; Beltram, Fabio

    2005-08-05

    Electrostatic control of the magnetization of a normal mesoscopic conductor is analyzed in a hybrid superconductor-normal-conductor-superconductor system. This effect stems from the interplay between the nonequilibrium condition in the normal region and the Zeeman splitting of the quasi-particle density of states of the superconductor subjected to a static in-plane magnetic field. Unexpected spin-dependent effects such as magnetization suppression, diamagnetic-like response of the susceptibility, as well as spin-polarized current generation are the most remarkable features presented. The impact of scattering events is evaluated and lets us show that this effect is compatible with realistic material properties and fabrication techniques.

  5. Nonequilibrium theory of flame propagation

    International Nuclear Information System (INIS)

    Merzhanov, A.G.

    1995-01-01

    The nonequilibrium theory of flame propagation is considered as applied to the following three processes of wave propagation: the combustion waves of the second kind, the combustion waves with broad reaction zones, and the combustion waves with chemical stages. Kinetic and combustion wave parameters are presented for different in composition mixtures of boron and transition metals, such as Zr, Hf, Ti, Nb, Ta, Mo, as well as for the Ta-N, Zr-C-H, Nb-B-O systems to illustrate specific features of the above-mentioned processes [ru

  6. A covariant representation of the Ball–Chiu vertex

    International Nuclear Information System (INIS)

    Ahmadiniaz, Naser; Schubert, Christian

    2013-01-01

    In nonabelian gauge theory the three-gluon vertex function contains important structural information, in particular on infrared divergences, and is also an essential ingredient in the Schwinger–Dyson equations. Much effort has gone into analyzing its general structure, and at the one-loop level also a number of explicit computations have been done, using various approaches. Here we use the string-inspired formalism to unify the calculations of the scalar, spinor and gluon loop contributions to the one-loop vertex, leading to an extremely compact representation in all cases. The vertex is computed fully off-shell and in dimensionally continued form, so that it can be used as a building block for higher-loop calculations. We find that the Bern–Kosower loop replacement rules, originally derived for the on-shell case, hold off-shell as well. We explain the relation of the structure of this representation to the low-energy effective action, and establish the precise connection with the standard Ball–Chiu decomposition of the vertex. This allows us also to predict that the vanishing of the completely antisymmetric coefficient function S of this decomposition is not a one-loop accident, but persists at higher-loop orders. The sum rule found by Binger and Brodsky, which leads to the vanishing of the one-loop vertex in N=4 SYM theory, in the present approach relates to worldline supersymmetry

  7. A covariant representation of the Ball–Chiu vertex

    Energy Technology Data Exchange (ETDEWEB)

    Ahmadiniaz, Naser, E-mail: naser@ifm.umich.mx [Instituto de Física y Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio C-3, Apdo. Postal 2-82, C.P. 58040, Morelia, Michoacán (Mexico); Dipartimento di Fisica, Università di Bologna and INFN, Sezione di Bologna, Via Irnerio 46, I-40126 Bologna (Italy); Schubert, Christian, E-mail: schubert@ifm.umich.mx [Instituto de Física y Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio C-3, Apdo. Postal 2-82, C.P. 58040, Morelia, Michoacán (Mexico); Dipartimento di Fisica, Università di Bologna and INFN, Sezione di Bologna, Via Irnerio 46, I-40126 Bologna (Italy); Max-Planck-Institut für Gravitationsphysik, Albert-Einstein-Institut, Mühlenberg 1, D-14476 Potsdam (Germany)

    2013-04-21

    In nonabelian gauge theory the three-gluon vertex function contains important structural information, in particular on infrared divergences, and is also an essential ingredient in the Schwinger–Dyson equations. Much effort has gone into analyzing its general structure, and at the one-loop level also a number of explicit computations have been done, using various approaches. Here we use the string-inspired formalism to unify the calculations of the scalar, spinor and gluon loop contributions to the one-loop vertex, leading to an extremely compact representation in all cases. The vertex is computed fully off-shell and in dimensionally continued form, so that it can be used as a building block for higher-loop calculations. We find that the Bern–Kosower loop replacement rules, originally derived for the on-shell case, hold off-shell as well. We explain the relation of the structure of this representation to the low-energy effective action, and establish the precise connection with the standard Ball–Chiu decomposition of the vertex. This allows us also to predict that the vanishing of the completely antisymmetric coefficient function S of this decomposition is not a one-loop accident, but persists at higher-loop orders. The sum rule found by Binger and Brodsky, which leads to the vanishing of the one-loop vertex in N=4 SYM theory, in the present approach relates to worldline supersymmetry.

  8. Energy repartition in the nonequilibrium steady state

    NARCIS (Netherlands)

    Yan, Peng; Bauer, G.E.; Zhang, Huaiwu

    2017-01-01

    The concept of temperature in nonequilibrium thermodynamics is an outstanding theoretical issue. We propose an energy repartition principle that leads to a spectral (mode-dependent) temperature in steady-state nonequilibrium systems. The general concepts are illustrated by analytic solutions of

  9. Non-dissipative effects in nonequilibrium systems

    CERN Document Server

    Maes, Christian

    2018-01-01

    This book introduces and discusses both the fundamental aspects and the measurability of applications of time-symmetric kinetic quantities, outlining the features that constitute the non-dissipative branch of non-equilibrium physics. These specific features of non-equilibrium dynamics have largely been ignored in standard statistical mechanics texts. This introductory-level book offers novel material that does not take the traditional line of extending standard thermodynamics to the irreversible domain. It shows that although stationary dissipation is essentially equivalent with steady non-equilibrium and ubiquitous in complex phenomena, non-equilibrium is not determined solely by the time-antisymmetric sector of energy-entropy considerations. While this should not be very surprising, this book provides timely, simple reminders of the role of time-symmetric and kinetic aspects in the construction of non-equilibrium statistical mechanics.

  10. Track and Vertex Reconstruction in the ATLAS Experiment

    CERN Document Server

    Lacuesta, V; The ATLAS collaboration

    2012-01-01

    The track and vertex reconstruction algorithms of the ATLAS Inner Detector have demonstrated excellent performance in the early data from the LHC. However, the rapidly increas- ing number of interactions per bunch crossing introduces new challenges both in computational aspects and physics performance. The combination of both silicon and gas based detectors provides high precision impact parameter and momentum measurement of charged particles, with high efficiency and small fake rate. Vertex reconstruction is used to identify with high efficiency the hard scattering process and to measure the amount of pile-up interactions, both aspects are cru- cial for many physics analyses. The performance of track and vertex reconstruction efficiency and resolution achieved in the 2011 and 2012 data-taking period are presented.

  11. Track and Vertex Reconstruction in the ATLAS Experiment

    CERN Document Server

    Lacuesta, V; The ATLAS collaboration

    2012-01-01

    The track and vertex reconstruction algorithms of the ATLAS Inner Detector have demonstrated excellent performance in the early data from the LHC. However, the rapidly increas- ing number of interactions per bunch crossing introduces new challenges both in computational aspects and physics performance. The combination of both silicon and gas based detectors pro- vides high precision impact parameter and momentum measurement of charged particles, with high efficiency and small fake rate. Vertex reconstruction is used to identify with high efficiency the hard scattering process and to measure the amount of pile-up interactions, both aspects are cru- cial for many physics analyses. The performance of track and vertex reconstruction efficiency and resolution achieved in the 2011 and 2012 data-taking period are presented.

  12. Barrel silicon vertex tracker for PHENIX at RHIC

    International Nuclear Information System (INIS)

    Ohnishi, Hiroaki

    2005-01-01

    The barrel silicon vertex tracker has been proposed as an upgrade project of the PHENIX experiment at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory. The prime motivation for this new detector is to provide precision measurements of heavy-quark production (charm and beauty) in A + A, p(d) + A, and polarized p + p collisions. The current design of the silicon vertex tracker comprises a four-layer barrel detector, built from two internal layers of pixel detectors and two external layers of projective 'stripixels' which complement the central spectrometer arms of PHENIX. In this paper, the physics motivation of the silicon vertex tracker upgrade and the concept of the new detector will be discussed. Moreover, the status of the new development and beginning production of the silicon detectors will be presented

  13. Track and vertex reconstruction in the ATLAS experiment

    International Nuclear Information System (INIS)

    Lacuesta, V

    2013-01-01

    The track and vertex reconstruction algorithms of the ATLAS Inner Detector have demonstrated excellent performance in the early data from the LHC. However, the rapidly increasing number of interactions per bunch crossing introduces new challenges both in computational aspects and physics performance. The combination of both silicon and gas based detectors provides high precision impact parameter and momentum measurement of charged particles, with high efficiency and small fake rate. Vertex reconstruction is used to identify with high efficiency the hard scattering process and to measure the amount of pile-up interactions, both aspects are crucial for many physics analyses. The performance of track and vertex reconstruction efficiency and resolution achieved in the 2011 and 2012 data-taking period are presented.

  14. Plethystic vertex operators and boson-fermion correspondences

    International Nuclear Information System (INIS)

    Fauser, Bertfried; Jarvis, Peter D; King, Ronald C

    2016-01-01

    We study the algebraic properties of plethystic vertex operators, introduced in (2010 J. Phys. A: Math. Theor. 43 405202), underlying the structure of symmetric functions associated with certain generalized universal character rings of subgroups of the general linear group, defined to stabilize tensors of Young symmetry type characterized by a partition of arbitrary shape π . Here we establish an extension of the well-known boson-fermion correspondence involving Schur functions and their associated (Bernstein) vertex operators: for each π , the modes generated by the plethystic vertex operators and their suitably constructed duals, satisfy the anticommutation relations of a complex Clifford algebra. The combinatorial manipulations underlying the results involve exchange identities exploiting the Hopf-algebraic structure of certain symmetric function series and their plethysms. (paper)

  15. Measurement of Rb Using a Vertex Mass Tag

    International Nuclear Information System (INIS)

    Steiner, R.; Benvenuti, A.C.; Coller, J.A.; Hedges, S.J.; Johnson, A.S.; Shank, J.T.; Whitaker, J.S.; Allen, N.J.; Cotton, R.; Dervan, P.J.; Hasan, A.; McKemey, A.K.; Watts, S.J.; Caldwell, D.O.; Lu, A.; Yellin, S.J.; Cavalli-Sforza, M.; Coyne, D.G.; Fernandez, J.P.; Liu, X.; Reinertsen, P.L.; Schalk, T.; Schumm, B.A.; DOliveira, A.; Johnson, R.A.; Meadows, B.T.; Nussbaum, M.; Dima, M.; Harton, J.L.; Smy, M.B.; Staengle, H.; Wilson, R.J.; Baranko, G.; Fahey, S.; Fan, C.; Krishna, N.M.; Lauber, J.A.; Nauenberg, U.; Wagner, D.L.; Bazarko, A.O.; Bolton, T.; Rowson, P.C.; Shaevitz, M.H.; Camanzi, B.; Mazzucato, E.; Piemontese, L.; Calcaterra, A.; De Sangro, R.; Peruzzi, I.; Piccolo, M.; Eisenstein, B.I.; Gladding, G.; Karliner, I.; Shapiro, G.; Steiner, H.; Bardon, O.; Burrows, P.N.; Busza, W.; Cowan, R.F.; Dong, D.N.; Fero, M.J.; Gonzalez, S.; Kendall, H.W.; Lath, A.; Lia, V.; Osborne, L.S.; Quigley, J.; Taylor, F.E.; Torrence, E.; Verdier, R.; Williams, D.C.

    1998-01-01

    We report a new measurement of R b =Γ Z 0 →bbar b /Γ Z 0 →hadrons using a double tag technique, where the b hemisphere selection is based on the reconstructed mass of the B hadron decay vertex. The measurement was performed using a sample of 130x10 3 hadronic Z 0 events, collected with the SLD detector at SLC. The method utilizes the 3D vertexing abilities of the CCD pixel vertex detector and the small stable SLC beams to obtain a high b -tagging efficiency and purity. We obtain R b =0.2142±0.0034(stat) ±0.0015(syst)±0.0002( R c ) . copyright 1998 The American Physical Society

  16. Preliminary studies for the LHCb vertex detector vacuum system

    CERN Document Server

    Doets, M; Van Bakel, N; Van den Brand, J F J; van den Brand, Jo

    2000-01-01

    We lay down some general considerations which will serve as a starting point for design studies of a realistic LHCb vertex detector vacuum system. Based on these considerations, we propose a design strategy and identify issues to be further studied. In particular we try to outline some boundary conditions imposed by LHC and LHCb on the vacuum system. We discuss two possibilities for the LHCb vertex detector vacuum system. The preferred strategy uses a differentially pumped vacuum system with the silicon detectors separated from the beam line vacuum. Some estimations on static vacuum pressures and gas flows are presented.

  17. RAVE-a Detector-independent vertex reconstruction toolkit

    International Nuclear Information System (INIS)

    Waltenberger, Wolfgang; Mitaroff, Winfried; Moser, Fabian

    2007-01-01

    A detector-independent toolkit for vertex reconstruction (RAVE) is being developed, along with a standalone framework (VERTIGO) for testing, analyzing and debugging. The core algorithms represent state of the art for geometric vertex finding and fitting by both linear (Kalman filter) and robust estimation methods. Main design goals are ease of use, flexibility for embedding into existing software frameworks, extensibility, and openness. The implementation is based on modern object-oriented techniques, is coded in C++ with interfaces for Java and Python, and follows an open-source approach. A beta release is available

  18. Simulations with the PANDA micro-vertex-detector

    International Nuclear Information System (INIS)

    Kliemt, Ralf

    2013-01-01

    The PANDA experiment will be built at the upcoming FAIR facility at GSI in Darmstadt, featuring antiproton-proton reactions hadron physics in a medium energy range. Charm physics will play an important role and therefore secondary decays relatively close to the interaction zone as well. The MVD will be the detector closest to these and will provide high-quality vertex position measurements. Alongside the detector layout and hardware development a detailed detector simulation and reconstruction software is required. This work contains the detailed description and the performance studies of the software developed for the MVD. Furthermore, vertexing tools are introduced and their performance is studied for the MVD.

  19. Simulations of silicon vertex tracker for star experiment at RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Odyniec, G.; Cebra, D.; Christie, W.; Naudet, C.; Schroeder, L.; Wilson, W. [Lawrence Berkeley Lab., CA (United States); Liko, D. [Institut fur Hochenenergiephysik, Vienna, (Austria); Cramer, J.; Prindle, D.; Trainor, T. [Univ. of Washington, Seattle (United States); Braithwaite, W. [Univ. of Arkansas, Little Rock (United States)

    1991-12-31

    The first computer simulations to optimize the Silicon Vertex Tracker (SVT) designed for the STAR experiment at RHIC are presented. The physics goals and the expected complexity of the events at RHIC dictate the design of a tracking system for the STAR experiment. The proposed tracking system will consist of a silicon vertex tracker (SVT) to locate the primary interaction and secondary decay vertices and to improve the momentum resolution, and a time projection chamber (TPC), positioned inside a solenoidal magnet, for continuous tracking.

  20. The L3 vertex detector: design and performance

    Science.gov (United States)

    Akbari, H.; Alverson, G.; Anderhub, H.; Bao, J.; Behner, F.; Behrens, J.; Beissel, F.; Betev, B.; Biland, A.; Böhm, A.; Camps, C.; Chien, C.-Y.; Commichau, V.; Dieters, K.; Donat, A.; Djambazov, L.; Fisher, P.; Freibel, W.; Göttlicher, P.; Haensli, M.; Hangarter, K.; Hasan, A.; Heller, R.; Herten, U.; Hofer, H.; Glaubman, M.; Jung, H.; Leedom, I.; Leiste, R.; Liebmann, H.; Lohmann, W.; Neyer, C.; Newman, D.; MacDermott, M.; Maolinbay, M.; McNally, D.; Mnich, J.; Möller, M.; Orndorff, J.; Peng, Y.; Pevsner, A.; Pohl, M.; Quadleig, K.; Rahal-Callot, G.; Ren, D.; Reucroft, S.; Rieb, N.; Rinsche, U.; Röser, U.; Röhner, S.; Rose, J.; Schmitz, P.; Schulte, R.; Schultze, K.; Sens, J. C.; Spangler, J.; Spartiotis, C.; Spickermann, T.; Starosta, R.; Sultanov, G.; Suter, H.; Szcesny, H.; Taylor, L.; Tonisch, F.; Trowitzsch, G.; Ulbricht, J.; Viertel, G.; Vikas, P.; Virnich, H.; Vogt, H.; Von Gunten, H. P.; Waldmeier, S.; Weber, J.; Winands, T.; Zemp, P.

    1992-05-01

    The L3 vertex detector is comprised of the time expansion chamber (TEC), the Z-chamber and a layer of plastic scintillating fibers. The TEC has shown a high spatial resolution and an excellent multi-track reconstruction capability at LEP luminosity. The Z-chamber provides information about the z-coordinates of the tracks and the fibers are used for calibrating the drift velocity with a high precision. A description of the L3 vertex detector, its readout and data acquisition and its performance during the 1990 LEP running period is presented in this paper.

  1. The VELO (VErtex LOcator) at the LHCb experiment

    CERN Document Server

    De Capua, S.

    2008-01-01

    The LHCb silicon vertex locator (VELO) is an array of silicon planes installed in a retractable roman pot system, which will enable the LHCb experiment to reconstruct and trigger on b-hadrons produced in collisions at the LHC. The VELO will be also used to attempt measuring the absolute luminosity with a novel method based on vertex reconstruction of beam gas interactions. In this paper the VELO system, its construction and the results from the commissioning phase are presented. The options for a possible upgraded detector are also discussed.

  2. Simulations with the PANDA micro-vertex-detector

    Energy Technology Data Exchange (ETDEWEB)

    Kliemt, Ralf

    2013-07-17

    The PANDA experiment will be built at the upcoming FAIR facility at GSI in Darmstadt, featuring antiproton-proton reactions hadron physics in a medium energy range. Charm physics will play an important role and therefore secondary decays relatively close to the interaction zone as well. The MVD will be the detector closest to these and will provide high-quality vertex position measurements. Alongside the detector layout and hardware development a detailed detector simulation and reconstruction software is required. This work contains the detailed description and the performance studies of the software developed for the MVD. Furthermore, vertexing tools are introduced and their performance is studied for the MVD.

  3. The design and performance of the ZEUS micro vertex detector

    International Nuclear Information System (INIS)

    Polini, A.; Brock, I.; Goers, S.

    2007-08-01

    In order to extend the tracking acceptance, to improve the primary and secondary vertex reconstruction and thus enhancing the tagging capabilities for short lived particles, the ZEUS experiment at the HERA Collider at DESY installed a silicon strip vertex detector. The barrel part of the detector is a 63 cm long cylinder with silicon sensors arranged around an elliptical beampipe. The forward part consists of four circular shaped disks. In total just over 200k channels are read out using 2.9 m 2 of silicon. In this report a detailed overview of the design and construction of the detector is given and the performance of the completed system is reviewed. (orig.)

  4. INTRODUCTION: Nonequilibrium Processes in Plasmas

    Science.gov (United States)

    Petrović, Zoran; Marić, Dragana; Malović, Gordana

    2009-07-01

    This book aims to give a cross section from a wide range of phenomena that, to different degrees, fall under the heading of non-equilibrium phenomenology. The selection is, of course, biased by the interests of the members of the scientific committee and of the FP6 Project 026328 IPB-CNP Reinforcing Experimental Centre for Non-equilibrium Studies with Application in Nano-technologies, Etching of Integrated Circuits and Environmental Research. Some of the papers included here are texts based on selected lectures presented at the Second International Workshop on Non-equilibrium Processes in Plasmas and Environmental Science. However, this volume is not just the proceedings of that conference as it contains a number of papers from authors that did not attend the conference. The goal was to put together a volume that would cover the interests of the project and support further work. It is published in the Institute of Physics journal Journal of Physics: Conference Series to ensure a wide accessibility of the articles. The texts presented here range from in-depth reviews of the current status and past achievements to progress reports of currently developed experimental devices and recently obtained still unpublished results. All papers have been refereed twice, first when speakers were selected based on their reputation and recently published results, and second after the paper was submitted both by the editorial board and individual assigned referees according to the standards of the conference and of the journal. Nevertheless, we still leave the responsibility (and honours) for the contents of the papers to the authors. The papers in this book are review articles that give a summary of the already published work or present the work in progress that will be published in full at a later date (or both). In the introduction to the first volume, in order to show how far reaching, ubiquitous and important non-equilibrium phenomena are, we claimed that ever since the early

  5. Nonequilibrium fluctuations in a resistor.

    Science.gov (United States)

    Garnier, N; Ciliberto, S

    2005-06-01

    In small systems where relevant energies are comparable to thermal agitation, fluctuations are of the order of average values. In systems in thermodynamical equilibrium, the variance of these fluctuations can be related to the dissipation constant in the system, exploiting the fluctuation-dissipation theorem. In nonequilibrium steady systems, fluctuations theorems (FT) additionally describe symmetry properties of the probability density functions (PDFs) of the fluctuations of injected and dissipated energies. We experimentally probe a model system: an electrical dipole driven out of equilibrium by a small constant current I, and show that FT are experimentally accessible and valid. Furthermore, we stress that FT can be used to measure the dissipated power P = R I2 in the system by just studying the PDFs' symmetries.

  6. Magnetic topology, nonequilibrium, and dissipation

    International Nuclear Information System (INIS)

    Parker, E.N.

    1985-01-01

    Static equilibrium of a magnetic field throughout a large volume of highly conducting fluid requires a degree of topological symmetry that is generally lacking in nature. The dynamical nonequilibrium of the magnetic topologies in the real world forms current sheets across which there is active reconnection of the field, dissipating the energy of the magnetic strains and reducing the fields toward simpler forms. The magnetic fields in astronomical settings are generally subject to continual straining by the convection within their parent body. The work done on the field by the convection appears in the energy of the small-scale strains, and is soon dissipated by the reconnection. The intense heating of the tenuous outer atmosphere of stars by this mechanism appears to be responsible for most of the X-ray emission of ordinary stars

  7. Statistical thermodynamics of nonequilibrium processes

    CERN Document Server

    Keizer, Joel

    1987-01-01

    The structure of the theory ofthermodynamics has changed enormously since its inception in the middle of the nineteenth century. Shortly after Thomson and Clausius enunciated their versions of the Second Law, Clausius, Maxwell, and Boltzmann began actively pursuing the molecular basis of thermo­ dynamics, work that culminated in the Boltzmann equation and the theory of transport processes in dilute gases. Much later, Onsager undertook the elucidation of the symmetry oftransport coefficients and, thereby, established himself as the father of the theory of nonequilibrium thermodynamics. Com­ bining the statistical ideas of Gibbs and Langevin with the phenomenological transport equations, Onsager and others went on to develop a consistent statistical theory of irreversible processes. The power of that theory is in its ability to relate measurable quantities, such as transport coefficients and thermodynamic derivatives, to the results of experimental measurements. As powerful as that theory is, it is linear and...

  8. New modular form identities associated to generalized vertex operator algebras

    Czech Academy of Sciences Publication Activity Database

    Zuevsky, Alexander

    2015-01-01

    Roč. 16, č. 1 (2015), s. 607-623 ISSN 1787-2405 Institutional support: RVO:67985840 Keywords : vertex operator superalgebras * intertwining operators * Riemann surfaces Subject RIV: BA - General Mathematics Impact factor: 0.335, year: 2015 http://mat76.mat.uni-miskolc.hu/~mnotes/index.php?page=article&name=mmn_1138

  9. Fast simulation and topological vertex finding in JAVA

    International Nuclear Information System (INIS)

    Walkowiak, Wolfgang

    2001-01-01

    An overview of the fast Monte Carlo simulation for NLC detector studies as currently provided in the Java Analysis Studio environment is presented. Special emphasis is given to the simulation of tracks. In addition, the SLD collaboration's topological vertex finding algorithm (ZVTOP) has been implemented in the Java Analysis Studio framework

  10. W. K. H. Panofsky Prize Talk: The Silicon Vertex Trigger

    Science.gov (United States)

    Ristori, Luciano

    2009-05-01

    I will discuss the importance of real-time selection of events at a hadron collider, the ideas that led to the conception of the Silicon Vertex Trigger (SVT) and some historical notes on its construction and commissioning. I will also highlight some remarkable results obtained by CDF with the data selected by the SVT.

  11. Network Unfolding Map by Vertex-Edge Dynamics Modeling.

    Science.gov (United States)

    Verri, Filipe Alves Neto; Urio, Paulo Roberto; Zhao, Liang

    2018-02-01

    The emergence of collective dynamics in neural networks is a mechanism of the animal and human brain for information processing. In this paper, we develop a computational technique using distributed processing elements in a complex network, which are called particles, to solve semisupervised learning problems. Three actions govern the particles' dynamics: generation, walking, and absorption. Labeled vertices generate new particles that compete against rival particles for edge domination. Active particles randomly walk in the network until they are absorbed by either a rival vertex or an edge currently dominated by rival particles. The result from the model evolution consists of sets of edges arranged by the label dominance. Each set tends to form a connected subnetwork to represent a data class. Although the intrinsic dynamics of the model is a stochastic one, we prove that there exists a deterministic version with largely reduced computational complexity; specifically, with linear growth. Furthermore, the edge domination process corresponds to an unfolding map in such way that edges "stretch" and "shrink" according to the vertex-edge dynamics. Consequently, the unfolding effect summarizes the relevant relationships between vertices and the uncovered data classes. The proposed model captures important details of connectivity patterns over the vertex-edge dynamics evolution, in contrast to the previous approaches, which focused on only vertex or only edge dynamics. Computer simulations reveal that the new model can identify nonlinear features in both real and artificial data, including boundaries between distinct classes and overlapping structures of data.

  12. SVT: an online silicon vertex tracker for the CDF upgrade

    International Nuclear Information System (INIS)

    Bardi, A.; Belforte, S.; Berryhill, J.

    1997-07-01

    The SVT is an online tracker for the CDF upgrade which will reconstruct 2D tracks using information from the Silicon VerteX detector (SVXII) and Central Outer Tracker (COT). The precision measurement of the track impact parameter will then be used to select and record large samples of B hadrons. We discuss the overall architecture, algorithms, and hardware implementation of the system

  13. Tripartite connection condition for a quantum graph vertex

    Czech Academy of Sciences Publication Activity Database

    Cheon, T.; Exner, Pavel; Turek, Ondřej

    2010-01-01

    Roč. 375, č. 2 (2010), s. 113-118 ISSN 0375-9601 R&D Projects: GA MŠk LC06002 Institutional research plan: CEZ:AV0Z10480505 Keywords : Schrodinger operator * Singular vertex * Boundary conditions Subject RIV: BA - General Mathematics Impact factor: 1.963, year: 2010

  14. Vertex algebra generation of almost holomorphic modular forms

    Czech Academy of Sciences Publication Activity Database

    Zuevsky, Alexander

    2015-01-01

    Roč. 31, - (2015), s. 15-23 ISSN 0974-5750 Institutional support: RVO:67985840 Keywords : automorphic forms * non-holomorphic extension of Einstein series * vertex algebras Subject RIV: BA - General Mathematics http://www.scientificadvances.co.in/abstract/1/157/897

  15. Random matrices and the six-vertex model

    CERN Document Server

    Bleher, Pavel

    2013-01-01

    This book provides a detailed description of the Riemann-Hilbert approach (RH approach) to the asymptotic analysis of both continuous and discrete orthogonal polynomials, and applications to random matrix models as well as to the six-vertex model. The RH approach was an important ingredient in the proofs of universality in unitary matrix models. This book gives an introduction to the unitary matrix models and discusses bulk and edge universality. The six-vertex model is an exactly solvable two-dimensional model in statistical physics, and thanks to the Izergin-Korepin formula for the model with domain wall boundary conditions, its partition function matches that of a unitary matrix model with nonpolynomial interaction. The authors introduce in this book the six-vertex model and include a proof of the Izergin-Korepin formula. Using the RH approach, they explicitly calculate the leading and subleading terms in the thermodynamic asymptotic behavior of the partition function of the six-vertex model with domain wa...

  16. Tests of track segment and vertex finding with neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Denby, B.; Lessner, E. (Fermi National Accelerator Lab., Batavia, IL (USA)); Lindsey, C.S. (Iowa State Univ. of Science and Technology, Ames, IA (USA))

    1990-04-01

    Feed forward neural networks have been trained, using back-propagation, to find the slopes of simulated track segments in a straw chamber and to find the vertex of tracks from both simulated and real events in a more conventional drift chamber geometry. Network architectures, training, and performance are presented. 12 refs., 7 figs.

  17. Performance of the CDF Silicon VerteX detector

    International Nuclear Information System (INIS)

    Schneider, O.

    1992-11-01

    The current status of the online and offline performance of the CDF Silicon VerteX detector is presented. So far, at low radiation dose, the device delivers good quality data. After the latest alignment using collision data, a spatial resolution of 13 pm is achieved in the transverse plane, demonstrating that CDF has a powerful tool to detect b decay vertices

  18. Self-locking degree-4 vertex origami structures.

    Science.gov (United States)

    Fang, Hongbin; Li, Suyi; Wang, K W

    2016-11-01

    A generic degree-4 vertex (4-vertex) origami possesses one continuous degree-of-freedom for rigid folding, and this folding process can be stopped when two of its facets bind together. Such facet-binding will induce self-locking so that the overall structure stays at a pre-specified configuration without additional locking elements or actuators. Self-locking offers many promising properties, such as programmable deformation ranges and piecewise stiffness jumps, that could significantly advance many adaptive structural systems. However, despite its excellent potential, the origami self-locking features have not been well studied, understood, and used. To advance the state of the art, this research conducts a comprehensive investigation on the principles of achieving and harnessing self-locking in 4-vertex origami structures. Especially, for the first time, this study expands the 4-vertex structure construction from single-component to dual-component designs and investigates their self-locking behaviours. By exploiting various tessellation designs, this research discovers that the dual-component designs offer the origami structures with extraordinary attributes that the single-component structures do not have, which include the existence of flat-folded locking planes, programmable locking points and deformability. Finally, proof-of-concept experiments investigate how self-locking can effectively induce piecewise stiffness jumps. The results of this research provide new scientific knowledge and a systematic framework for the design, analysis and utilization of self-locking origami structures for many potential engineering applications.

  19. Domination parameters of a graph with added vertex

    Directory of Open Access Journals (Sweden)

    Maciej Zwierzchowski

    2004-01-01

    Full Text Available Let \\(G=(V,E\\ be a graph. A subset \\(D\\subseteq V\\ is a total dominating set of \\(G\\ if for every vertex \\(y\\in V\\ there is a vertex \\(x\\in D\\ with \\(xy\\in E\\. A subset \\(D\\subseteq V\\ is a strong dominating set of \\(G\\ if for every vertex \\(y\\in V-D\\ there is a vertex \\(x\\in D\\ with \\(xy\\in E\\ and \\(\\deg _{G}(x\\geq\\deg _{G}(y\\. The total domination number \\(\\gamma _{t}(G\\ (the strong domination number \\(\\gamma_{S}(G\\ is defined as the minimum cardinality of a total dominating set (a strong dominating set of \\(G\\. The concept of total domination was first defined by Cockayne, Dawes and Hedetniemi in 1980 [Cockayne E. J., Dawes R. M., Hedetniemi S. T.: Total domination in graphs. Networks 10 (1980, 211–219], while the strong domination was introduced by Sampathkumar and Pushpa Latha in 1996 [Pushpa Latha L., Sampathkumar E.: Strong weak domination and domination balance in a graph. Discrete Mathematics 161 (1996, 235–242]. By a subdivision of an edge \\(uv\\in E\\ we mean removing edge \\(uv\\, adding a new vertex \\(x\\, and adding edges \\(ux\\ and \\(vx\\. A graph obtained from \\(G\\ by subdivision an edge \\(uv\\in E\\ is denoted by \\(G\\oplus u_{x}v_{x}\\. The behaviour of the total domination number and the strong domination number of a graph \\(G\\oplus u_{x}v_{x}\\ is developed.

  20. Referesher Course on Contemporary Non-Equilibrium ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 15; Issue 7. Referesher Course on Contemporary Non-Equilibrium Thermodynamics and Statistical Mechanics. Information and Announcements Volume 15 Issue 7 July 2010 pp 678-678 ...

  1. Nonequilibrium molecular dynamics: The first 25 years

    International Nuclear Information System (INIS)

    Hoover, W.G.

    1992-08-01

    Equilibrium Molecular Dynamics has been generalized to simulate Nonequilibrium systems by adding sources of thermodynamic heat and work. This generalization incorporates microscopic mechanical definitions of macroscopic thermodynamic and hydrodynamic variables, such as temperature and stress, and augments atomistic forces with special boundary, constraint, and driving forces capable of doing work on, and exchanging heat with, an otherwise Newtonian system. The underlying Lyapunov instability of these nonequilibrium equations of motion links microscopic time-reversible deterministic trajectories to macroscopic time-irreversible hydrodynamic behavior as described by the Second Law of Thermodynamics. Green-Kubo linear-response theory has been checked. Nonlinear plastic deformation, intense heat conduction, shockwave propagation, and nonequilibrium phase transformation have all been simulated. The nonequilibrium techniques, coupled with qualitative improvements in parallel computer hardware, are enabling simulations to approximate real-world microscale and nanoscale experiments

  2. Nonequilibrium Green's functions approach to inhomogeneous systems

    CERN Document Server

    Balzer, Karsten

    2013-01-01

    This book offers a self-contained introduction to non-equilibrium quantum particle dynamics for inhomogeneous systems, including a survey of recent breakthroughs pioneered by the authors and others. The approach is based on real-time Green's functions.

  3. Noncommutative QFT and renormalization

    International Nuclear Information System (INIS)

    Grosse, H.; Wulkenhaar, R.

    2006-01-01

    It was a great pleasure for me (Harald Grosse) to be invited to talk at the meeting celebrating the 70th birthday of Prof. Julius Wess. I remember various interactions with Julius during the last years: At the time of my studies at Vienna with Walter Thirring, Julius left already Vienna, I learned from his work on effective chiral Lagrangians. Next we met at various conferences and places like CERN (were I worked with Andre Martin, an old friend of Julius), and we all learned from Julius' and Bruno's creation of supersymmetry, next we realized our common interests in noncommutative quantum field theory and did have an intensive exchange. Julius influenced our perturbative approach to gauge field theories were we used the Seiberg-Witten map after his advice. And finally I lively remember the sad days when during my invitation to Vienna Julius did have the serious heart attack. So we are very happy, that you recovered so well, and we wish you all the best for the forthcoming years. Many happy recurrences. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  4. Non-equilibrium dog-flea model

    Science.gov (United States)

    Ackerson, Bruce J.

    2017-11-01

    We develop the open dog-flea model to serve as a check of proposed non-equilibrium theories of statistical mechanics. The model is developed in detail. Then it is applied to four recent models for non-equilibrium statistical mechanics. Comparison of the dog-flea solution with these different models allows checking claims and giving a concrete example of the theoretical models.

  5. Plasma wave instabilities in nonequilibrium graphene

    DEFF Research Database (Denmark)

    Aryal, Chinta M.; Hu, Ben Yu-Kuang; Jauho, Antti-Pekka

    2016-01-01

    We study two-stream instabilities in a nonequilibrium system in which a stream of electrons is injected into doped graphene. As with equivalent nonequilibrium parabolic band systems, we find that the graphene systems can support unstable charge-density waves whose amplitudes grow with time. We...... of the injected electrons that maximizes the growth rate increases with increasing | q |. We compare the range and strength of the instability in graphene to that of two- and three-dimensional parabolic band systems....

  6. Nonequilibrium quantum meson gas: Dimensional reduction

    Science.gov (United States)

    Alvarez-Estrada, R. F.

    2009-07-01

    A nonequilibrium quantum gas of interacting relativistic effective mesons, ressembling qualitatively those produced in a heavy-ion collision, is described by a scalar φ^{{4}}_{} quantum field in (1 + 3) -dimensional Minkowski space. For high temperature and large temporal and spatial scales, we justify that classical statistical mechanics including quantum renormalization effects describe approximately the gas: nonequilibrium dimensional reduction (NEDR). As a source of hints, we treat the gas at equilibrium in real-time formalism and obtain simplifications for high temperature and large spatial scales, thereby extending a useful equilibrium dimensional reduction known for the imaginary-time formalism. By assumption, the nonequilibrium initial state of the gas, not far from thermal equilibrium, includes interactions and inhomogeneities. We use nonequilibrium real-time generating functionals and correlators at nonzero temperature. In the NEDR regime, our arguments yield: 1) renormalized correlators simplify, 2) the perturbative series for those simplified correlators can be resummed into a new nonequilibrium generating functional, Z’ r, dr , which is super-renormalizable and includes renormalization effects (large position-dependent thermal self-energies and effective couplings). Z’ r, dr could enable to study nonperturbatively changes in the phase structures of the field, by proceeding from the nonequilibrium quantum regime to the NEDR one.

  7. Aerospace Applications of Non-Equilibrium Plasma

    Science.gov (United States)

    Blankson, Isaiah M.

    2016-01-01

    Nonequilibrium plasma/non-thermal plasma/cold plasmas are being used in a wide range of new applications in aeronautics, active flow control, heat transfer reduction, plasma-assisted ignition and combustion, noise suppression, and power generation. Industrial applications may be found in pollution control, materials surface treatment, and water purification. In order for these plasma processes to become practical, efficient means of ionization are necessary. A primary challenge for these applications is to create a desired non-equilibrium plasma in air by preventing the discharge from transitioning into an arc. Of particular interest is the impact on simulations and experimental data with and without detailed consideration of non-equilibrium effects, and the consequences of neglecting non-equilibrium. This presentation will provide an assessment of the presence and influence of non-equilibrium phenomena for various aerospace needs and applications. Specific examples to be considered will include the forward energy deposition of laser-induced non-equilibrium plasmoids for sonic boom mitigation, weakly ionized flows obtained from pulsed nanosecond discharges for an annular Hall type MHD generator duct for turbojet energy bypass, and fundamental mechanisms affecting the design and operation of novel plasma-assisted reactive systems in dielectric liquids (water purification, in-pipe modification of fuels, etc.).

  8. Cycles through all finite vertex sets in infinite graphs

    DEFF Research Database (Denmark)

    Kundgen, Andre; Li, Binlong; Thomassen, Carsten

    2017-01-01

    that every one-ended planar cubic 3-connected bipartite graph has a Hamiltonian curve. It is also equivalent to the statement that every planar cubic 3-connected bipartite graph with a nowhere-zero 3-flow (with no restriction on the number of ends) has a Hamiltonian curve. However, there are 7-ended planar......A closed curve in the Freudenthal compactification |G| of an infinite locally finite graph G is called a Hamiltonian curve if it meets every vertex of G exactly once (and hence it meets every end at least once). We prove that |G| has a Hamiltonian curve if and only if every finite vertex set of G...... is contained in a cycle of G. We apply this to extend a number of results and conjectures on finite graphs to Hamiltonian curves in infinite locally finite graphs. For example, Barnette’s conjecture (that every finite planar cubic 3-connected bipartite graph is Hamiltonian) is equivalent to the statement...

  9. Bs⁎BK vertex from QCD sum rules

    International Nuclear Information System (INIS)

    Cerqueira, A.; Osório Rodrigues, B.; Bracco, M.E.

    2012-01-01

    The form factors and the coupling constant of the B s ⁎ BK vertex are calculated using the QCD sum rules method. Three-point correlation functions are computed considering both K and B mesons off-shell and, after an extrapolation of the QCDSR results, we obtain the coupling constant of the vertex. We study the uncertainties in our result by calculating a third form factor obtained when the B s ⁎ is the off-shell meson, considering other acceptable structures and computing the variations of the sum rules' parameters. The form factors obtained have different behaviors but their simultaneous extrapolations reach to the same value of the coupling constant g B s ⁎ BK =10.6±1.7. We compare our result with other theoretical estimates.

  10. Internal alignement of the BABAR silicon vertex tracking detector

    CERN Document Server

    Brown, D; Roberts, D

    2007-01-01

    The BABAR Silicon Vertex Tracker (SVT ) is a five-layer double-sided silicon detector designed to provide precise measurements of the position and direction of primary tracks, and to fully reconstruct low-momentum tracks produced in e+e¡ collisions at the PEP-II asymmetric collider at Stanford Linear Accelerator Center. This paper describes the design, implementation, performance and validation of the local alignment procedure used to determine the relative positions and orientations of the 340 Silicon Vertex Trackerwafers. This procedure uses a tuned mix of lab-bench measurements and complementary in-situ experimental data to control systematic distortions. Wafer positions and orientations are determined by minimizing a Â2 computed using these data for each wafer individually, iterating to account for between-wafer correlations. A correction for aplanar distortions of the silicon wafers is measured and applied. The net effect of residual mis-alignments on relevant physical variables evaluated in special co...

  11. Vertex detectors: The state of the art and future prospects

    International Nuclear Information System (INIS)

    Damerell, C.J.S.

    1997-01-01

    We review the current status of vertex detectors (tracking microscopes for the recognition of charm and bottom particle decays). The reasons why silicon has become the dominant detector medium are explained. Energy loss mechanisms are reviewed, as well as the physics and technology of semiconductor devices, emphasizing the areas of most relevance for detectors. The main design options (microstrips and pixel devices, both CCD's and APS's) are discussed, as well as the issue of radiation damage, which probably implies the need to change to detector media beyond silicon for some vertexing applications. Finally, the evolution of key performance parameters over the past 15 years is reviewed, and an attempt is made to extrapolate to the likely performance of detectors working at the energy frontier ten years from now

  12. Covariant superstring fermionic amplitudes. Vertex operators and picture changing

    International Nuclear Information System (INIS)

    Aldazabal, G.; Nunez, C.; Bonini, M.

    1988-07-01

    Massive Ramond and Neveu-Schwarz vertex operators in the -1/2 and -1 ghost representations respectively are obtained from the factorization of the scattering amplitude of an arbitrary number of bosonic and fermionic massless states on general Riemann surfaces. The correlators for the ghost field of charge -1 and its derivatives are given as well as the normal ordering prescriptions to be used in computing scattering amplitudes. The vertex operators for the massless and the first two excited levels, both of the Ramond and the Neveu-Schwarz sector are given explicitly. The picture changing mechanism is considered and applied to relate the Neveu-Schwarz vertices in different representations. (author). 22 refs

  13. Worldline calculation of the three-gluon vertex

    International Nuclear Information System (INIS)

    Ahmadiniaz, N.; Schubert, C.

    2012-01-01

    The three-gluon vertex is a basic object of interest in nonabelian gauge theory. At the one-loop level, it has been calculated and analyzed by a number of authors. Here we use the worldline formalism to unify the calculations of the scalar, spinor and gluon loop contributions to the one-loop vertex, leading to an extremely compact representation in terms of field strength tensors. We verify its equivalence with previously obtained representations, and explain the relation of its structure to the low-energy effective action. The sum rule found by Binger and Brodsky for the scalar, spinor and gluon loop contributions in the present approach relates to worldline supersymmetry.

  14. On the zero crossing of the three-gluon vertex

    Energy Technology Data Exchange (ETDEWEB)

    Athenodorou, A. [Department of Physics, University of Cyprus, POB 20537, 1678 Nicosia (Cyprus); Binosi, D., E-mail: binosi@ectstar.eu [European Centre for Theoretical Studies in Nuclear Physics and Related Areas - ECT* and Fondazione Bruno Kessler, Villa Tambosi, Strada delle Tabarelle 286, I-38050 Villazzano (Italy); Boucaud, Ph. [Laboratoire de Physique Théorique (UMR8627), CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405 Orsay (France); De Soto, F. [Dpto. Sistemas Físicos, Químicos y Naturales, Univ. Pablo de Olavide, 41013 Sevilla (Spain); Papavassiliou, J. [Department of Theoretical Physics and IFIC, University of Valencia-CSIC, E-46100, Valencia (Spain); Rodríguez-Quintero, J. [Department of Integrated Sciences, University of Huelva, E-21071 Huelva (Spain); Zafeiropoulos, S. [Institut für Theoretische Physik, Goethe-Universität Frankfurt, Max-von-Laue-Str. 1, 60438 Frankfurt am Main (Germany)

    2016-10-10

    We report on new results on the infrared behavior of the three-gluon vertex in quenched Quantum Chromodynamics, obtained from large-volume lattice simulations. The main focus of our study is the appearance of the characteristic infrared feature known as ‘zero crossing’, the origin of which is intimately connected with the nonperturbative masslessness of the Faddeev–Popov ghost. The appearance of this effect is clearly visible in one of the two kinematic configurations analyzed, and its theoretical origin is discussed in the framework of Schwinger–Dyson equations. The effective coupling in the momentum subtraction scheme that corresponds to the three-gluon vertex is constructed, revealing the vanishing of the effective interaction at the exact location of the zero crossing.

  15. The secondary vertex finding algorithm with the ATLAS detector

    CERN Document Server

    Heer, Sebastian; The ATLAS collaboration

    2017-01-01

    A high performance identification of jets, produced via fragmentation of bottom quarks, is crucial for the ATLAS physics program. These jets can be identified by exploiting the presence of cascade decay vertices from bottom hadrons. A general vertex-finding algorithm is introduced and its ap- plication to the search for secondary vertices inside jets is described. Kinematic properties of the reconstructed vertices are used to construct several b-jet identification algorithms. The features and performance of the secondary vertex finding algorithm in a jet, as well as the performance of the jet tagging algorithms, are studied using simulated $pp$ -> $t\\bar{t}$ events at a centre-of-mass energy of 13 TeV.

  16. Impact parameter trigger and vertex detector for forward collider

    International Nuclear Information System (INIS)

    Selove, W.

    1993-01-01

    In a forward collider design, Coulomb scattering produces an unavoidable smearing of the vertex region by low-p t tracks. A detector and triggering design is described which aims at differentiating B events from minimum bias events with high efficiency, in spite of this smearing, by measuring momentum and p t of all tracks in real time, and triggering only when an event shows a number of high-p t tracks with substantial impact parameters. Triggering efficiency an order of magnitude larger than for a lepton trigger can be anticipated. Detector planes are located within 4 millimeters of the beam line; a replaceable-vertex-region design provides for rapid replacement of radiation damaged closest elements at time intervals of a few months

  17. Vertex detectors: The state of the art and future prospects

    Energy Technology Data Exchange (ETDEWEB)

    Damerell, C.J.S. [Rutherford Appleton Laboratory, Didcot (United Kingdom)

    1997-01-01

    We review the current status of vertex detectors (tracking microscopes for the recognition of charm and bottom particle decays). The reasons why silicon has become the dominant detector medium are explained. Energy loss mechanisms are reviewed, as well as the physics and technology of semiconductor devices, emphasizing the areas of most relevance for detectors. The main design options (microstrips and pixel devices, both CCD`s and APS`s) are discussed, as well as the issue of radiation damage, which probably implies the need to change to detector media beyond silicon for some vertexing applications. Finally, the evolution of key performance parameters over the past 15 years is reviewed, and an attempt is made to extrapolate to the likely performance of detectors working at the energy frontier ten years from now.

  18. The silicon vertex locator for the LHCb upgrade

    CERN Document Server

    Head, Tim

    2014-01-01

    The upgrade of the LHCb experiment, planned for 2018, will transform the entire readout to a triggerless system being read out at 40 MHz. The upgraded silicon vertex detector (VELO) must be light weight, radiation hard, and compatible with LHC vacuum requirements. It must be capable of fast pattern recognition, fast track reconstruction and high precision vertexing. This challenge is being met with a new VELO design based on hybrid pixel detectors positioned to within 5 mm of the LHC colliding beams. The detector will be shielded from the beam by a View the MathML source~300μm thick aluminium foil. Evaporative CO2 coolant circulating in micro-channels embedded in a thin silicon substrate will be used for cooling.

  19. Six-vertex model and Schramm-Loewner evolution

    Science.gov (United States)

    Kenyon, Richard; Miller, Jason; Sheffield, Scott; Wilson, David B.

    2017-05-01

    Square ice is a statistical mechanics model for two-dimensional ice, widely believed to have a conformally invariant scaling limit. We associate a Peano (space-filling) curve to a square ice configuration, and more generally to a so-called six-vertex model configuration, and argue that its scaling limit is a space-filling version of the random fractal curve SL E κ, Schramm-Loewner evolution with parameter κ , where 4 <κ ≤12 +8 √{2 } . For square ice, κ =12 . At the "free-fermion point" of the six-vertex model, κ =8 +4 √{3 } . These unusual values lie outside the classical interval 2 ≤κ ≤8 .

  20. Vertex finding by sparse model-based clustering

    Science.gov (United States)

    Frühwirth, R.; Eckstein, K.; Frühwirth-Schnatter, S.

    2016-10-01

    The application of sparse model-based clustering to the problem of primary vertex finding is discussed. The observed z-positions of the charged primary tracks in a bunch crossing are modeled by a Gaussian mixture. The mixture parameters are estimated via Markov Chain Monte Carlo (MCMC). Sparsity is achieved by an appropriate prior on the mixture weights. The results are shown and compared to clustering by the expectation-maximization (EM) algorithm.

  1. Silicon vertex detector upgrade in the ALPHA experiment

    CERN Document Server

    Amole, C; Ashkezari, M.D; Baquero-Ruiz, M; Bertsche, W; Burrows, C; Butler, E; Capra, A; Cesar, C.L; Chapman, S; Charlton, M; Deller, A; Eriksson, S; Fajans, J; Friesen, T; Fujiwara, M.C; Gill, D.R; Gutierrez, A; Hangst, J.S; Hardy, W.N; Hayden, M.E; Humphries, A.J; Isaac, C.A; Jonsell, S; Kurchaninov, L; Little, A; Madsen, N; McKenna, J.T.K; Menary, S; Napoli, S.C; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Pusa, P; Rasmussen, C.Ø; Robicheaux, F; Sacramento, R.L; Sampson, J.A; Sarid, E; Seddon, D; Silveira, D.M; So, C; Stracka, S; Tharp, T; Thompson, R.I; Thornhill, J; Tooley, M.P; Van Der Werf, D.P; Wells, D

    2013-01-01

    The Silicon Vertex Detector (SVD) is the main diagnostic tool in the ALPHA-experiment. It provides precise spatial and timing information of antiproton (antihydrogen) annihilation events (vertices), and most importantly, the SVD is capable of directly identifying and analysing single annihilation events, thereby forming the basis of ALPHA ' s analysis. This paper describes the ALPHA SVD and its upgrade, installed in the ALPHA ' s new neutral atom trap.

  2. Superstring vertex operators and scattering amplitudes on arbitrary Riemann surfaces

    International Nuclear Information System (INIS)

    Aldazabel, G.; Nunez, C.; Iengo, R.; Bonini, M.

    1987-12-01

    The construction of scattering amplitudes involving arbitrary bosonic mass level states is considered in both the closed superstring and in the heterotic string theories, at any order of perturbation. From massless particle scattering on a general Riemann surface, the super-covariant form of the vertex operators is derived via factorization. The super-covariant rules, including the normal ordering prescriptions, to be used in computing amplitudes, are automatically given by this procedure. (author). 22 refs, 1 fig

  3. Technical Design Report for the: PANDA Micro Vertex Detector

    CERN Document Server

    Erni, W; Krusche, B; Steinacher, M; Heng, Y; Liu, Z; Liu, H; Shen, X; Wang, Q; Xu, H; Albrecht, M; Becker, J; Eickel, K; Feldbauer, F; Fink, M; Friedel, P; Heinsius, F H; Held, T; Koch, H; Kopf, B; Leyhe, M; Motzko, C; Pelizäus, M; Pychy, J; Roth, B; Schröder, T; Schulze, J; Steinke, M; Trifterer, T; Wiedner, U; Zhong, J; Beck, R; Becker, M; Bianco, S; Brinkmann, K -Th; Hammann, C; Hinterberger, F; Jäkel, R; Kaiser, D; Kliemt, R; Koop, K; Schmidt, C; Schnell, R; Thoma, U; Vlasov, P; Wendel, C; Winnebeck, A; Würschig, Th; Zaunick, H -G; Bianconi, A; Bragadireanu, M; Caprini, M; Ciubancan, M; Pantea, D; Tarta, P -D; De Napoli, M; Giacoppo, F; Rapisarda, E; Sfienti, C; Fiutowski, T; Idzik, N; Mindur, B; Przyborowski, D; Swientek, K; Bialkowski, E; Budzanowski, A; Czech, B; Kliczewski, S; Kozela, A; Kulessa, P; Lebiedowicz, P; Malgorzata, K; Pysz, K; Schäfer, W; Siudak, R; Szczurek, A; Brandys, P; Czyzewski, T; Czyzycki, W; Domagala, M; Hawryluk, M; Filo, G; Kwiatkowski, D; Lisowski, E; Lisowski, F; Bardan, W; Gil, D; Kamys, B; Kistryn, St; Korcyl, K; Krzemieñ, W; Magiera, A; Moskal, P; Rudy, Z; Salabura, P; Smyrski, J; Wroñska, A; Al-Turany, M; Arora, R; Augustin, I; Deppe, H; Dutta, D; Flemming, H; Götzen, K; Hohler, G; Karabowicz, R; Lehmann, D; Lewandowski, B; Lühning, J; Maas, F; Orth, H; Peters, K; Saito, T; Schepers, G; Schmidt, C J; Schmitt, L; Schwarz, C; Schwiening, J; Voss, B; Wieczorek, P; Wilms, A; Abazov, V M; Alexeev, G D; Arefiev, V A; Astakhov, V I; Barabanov, M Yu; Batyunya, B V; Davydov, Yu I; Dodokhov, V Kh; Efremov, A A; Fedunov, A G; Feshchenko, A A; Galoyan, A S; Grigoryan, S; Karmokov, A; Koshurnikov, E K; Lobanov, V I; Lobanov, Yu Yu; Makarov, A F; Malinina, L V; Malyshev, V L; Mustafaev, G A; Olshevski, A G; Pasyuk, M A; Perevalova, E A; Piskun, A A; Pocheptsov, T A; Pontecorvo, G; Rodionov, V K; Rogov, Yu N; Salmin, R A; Samartsev, A G; Sapozhnikov, M G; Shabratova, G S; Skachkova, A N; Skachkov, N B; Strokovsky, E A; Suleimanov, M K; Teshev, R Sh; Tokmenin, V V; Uzhinsky, V V; Vodopyanov, A S; Zaporozhets, S A; Zhuravlev, N I; Zorin, A G; Branford, D; Glazier, D; Watts, D; Woods, P; Britting, A; Eyrich, W; Lehmann, A; Uhlig, F; Dobbs, S; Metreveli, Z; Seth, K; Tann, B; Tomaradze, A; Bettoni, D; Carassiti, V; Dalpiaz, P; Drago, A; Fioravanti, E; Garzia, I; Negrini, M; Savriè, M; Stancari, G; Dulach, B; Gianotti, P; Guaraldo, C; Lucherini, V; Pace, E; Bersani, A; Macri, M; Marinelli, M; Parodi, R F; Dormenev, V; Drexler, P; Düren, M; Eisner, T; Foehl, K; Hayrapetyan, A; Koch, P; Krïoch, B; Kühn, W; Lange, S; Liang, Y; Liu, M; Merle, O; Metag, V; Moritz, M; Nanova, M; Novotny, R; Spruck, B; Stenzel, H; Strackbein, C; Thiel, M; Wang, Q; Clarkson, T; Euan, C; Hill, G; Hoek, M; Ireland, D; Kaiser, R; Keri, T; Lehmann, I; Livingston, K; Lumsden, P; MacGregor, D; McKinnon, B; Montgomery, R; Murray, M; Protopopescu, D; Rosner, G; Seitz, B; Yang, G; Babai, M; Biegun, A K; Glazenborg-Kluttig, A; Guliyev, E; Jothi, V S; Kavatsyuk, M; Lemmens, P; Löhner, H; Messchendorp, J; Poelman, T; Smit, H; van der Weele, J C; Sohlbach, H; Büscher, M; Dosdall, R; Dzhygadlo, R; Esch, S; Gillitzer, A; Goldenbaum, F; Grunwald, D; Jha, V; Kemmerling, G; Kleines, H; Lehrach, A; Maier, R; Mertens, M; Ohm, H; Pohl, D L; Prasuhn, D; Randriamalala, T; Ritman, J; Roeder, M; Sterzenbach, G; Stockmanns, T; Wintz, P; Wüstner, P; Xu, H; Kisiel, J; Li, S; Li, Z; Sun, Z; Xu, H; Fissum, K; Hansen, K; Isaksson, L; Lundin, M; Schröder, B; Achenbach, P; Denig, A; Distler, M; Fritsch, M; Kangh, D; Karavdina, A; Lauth, W; Michel, M; Espi, M C Mora; Pochodzalla, J; Sanchez, S; Sanchez-Lorente, A; Sfienti, C; Weber, T; Dormenev, V I; Fedorov, A A; Korzhik, M V; Missevitch, O V; Boukharov, A; Malyshev, O; Marishev, I; Semenov, A; Varma, R; Höppner, C; Ketzer, B; Konorov, I; Mann, A; Neubert, S; Paul, S; Vandenbroucke, M; Zhang, Q; Khoukaz, A; Rausmann, T; Täschner, A; Wessels, J; Baldin, E; Kotov, K; Peleganchuk, S; Tikhonov, Yu; Hennino, T; Imre, M; Kunne, R; Galliard, C Le; Normand, J P Le; Marchand, D; Maroni, A; Ong, S; Pouthas, J; Ramstein, B; Rosier, P; Sudol, M; Theneau, C; Tomasi-Gustafsson, E; Van de Wiele, J; Zerguerras, T; Boca, G; Braghieri, A; Costanza, S; Fontana, A; Genova, P; Lavezzi, L; Montagna, P; Rotondi, A; Buda, V; Abramov, V V; Davidenko, A M; Derevschikov, A A; Goncharenko, Y M; Grishin, V N; Kachanov, V A; Konstantinov, D A; Kormilitsin, V A; Matulenko, Y A; Melnik, Y M; Meschanin, A P; Minaev, N G; Mochalov, V V; Morozov, D A; Nogach, L V; Nurushev, S B; Ryazantsev, A V; Semenov, P A; Soloviev, L F; Uzunian, A V; Vasiliev, A N; Yakutin, A E; Belostotski, S; Gavrilov, G; Itzotov, A; Kisselev, A; Kravchenko, P; Manaenkov, S; Miklukho, O; Naryshkin, Y; Veretennikov, D; Vikhrov, V; Zhadanov, A; Bäck, T; Cederwall, B; Bargholtz, C; Gerén, L; Tegnér, P E; Thørngren, P; von Würtemberg, K M; Fava, L; Alberto, D; Amoroso, A; Bussa, M P; Busso, L; De Mori, F; Destefanis, M; Ferrero, L; Greco, M; Kugathasan, T; Maggiora, M; Marcello, S; Sosio, S; Spataro, S; Calvo, D; Coli, S; De Remigis, P; Filippi, A; Giraudo, G; Lusso, S; Mazza, G; Mignone, M; Rivetti, A; Wheadon, R; Zotti, L; Morra, O; Iazzi, F; Lavagno, A; Quarati, P; Szymanska, K; Birsa, R; Bradamante, F; Bressan, A; Martin, A; Clement, H; Galnander, B; Calén, H; Fransson, K; Johansson, T; Kupsc, A; Marciniewski, P; Thomé, E; Wolke, M; Zlomanczuk, J; Díaz, J; Ortiz, A; Buda, P; Dmowski, K; Korzeniewski, R; Przemyslaw, D; Slowinski, B; Borsuk, S; Chlopik, A; Guzik, Z; Kopec, J; Kozlowski, T; Melnychuk, D; Plominski, M; Szewinski, J; Traczyk, K; Zwieglinski, B; Bühler, P; Gruber, A; Kienle, P; Marton, J; Widmann, E; Zmeskal, J

    2012-01-01

    This document illustrates the technical layout and the expected performance of the Micro Vertex Detector (MVD) of the PANDA experiment. The MVD will detect charged particles as close as possible to the interaction zone. Design criteria and the optimisation process as well as the technical solutions chosen are discussed and the results of this process are subjected to extensive Monte Carlo physics studies. The route towards realisation of the detector is outlined.

  4. The effect of radiation damage on the vertex detector efficiency

    CERN Document Server

    Cooke, O

    1997-01-01

    97-023 This note describes a brief study into the effects of the radiation damage on the vertex detectorperformance. The noise increases as the detector is irradiated. Fixing the fraction of noise clusters to 0.1% by adjusting the thresholds brings about a loss in efficiency with increased irradiation. This loss in efficiency is parameterized, and some effects on the B->pi+pi- channel are shown.

  5. Fatigue crack shape prediction based on vertex singularity

    Czech Academy of Sciences Publication Activity Database

    Hutař, Pavel; Náhlík, Luboš

    2008-01-01

    Roč. 2, č. 1 (2008), s. 45-52 ISSN 1802-680X R&D Projects: GA ČR GA101/08/1623; GA ČR GP106/06/P239 Institutional research plan: CEZ:AV0Z20410507 Keywords : 3D vertex singularity * crack shape * fatigue crack propagation Subject RIV: JL - Materials Fatigue, Friction Mechanics

  6. The LHCb Vertex Locator – Performance and Radiation Damage

    CERN Document Server

    Oblakowska-Mucha, A

    2014-01-01

    LHCb is a dedicated flavour physics experiment at the Large Hadron Collider at CERN. The Vertex Locator (VELO) is an important part of a LHCb tracking system, enabling precision measurement of beauty and charm mesons’ flight distance. The VELO consist of a set of silicon micro-strip detectors, arranged in two retractable halves, operating only 7 mm from the interac- tion region. In these proceedings the VELO performance during the Run 1 is summarised and radiation damage studies are presented.

  7. Data driven processor 'Vertex Trigger' for B experiments

    International Nuclear Information System (INIS)

    Hartouni, E.P.

    1993-01-01

    Data Driven Processors (DDP's) are specialized computation engines configured to solve specific numerical problems, such as vertex reconstruction. The architecture of the DDP which is the subject of this talk was designed and implemented by W. Sippach and B.C. Knapp at Nevis Lab. in the early 1980's. This particular implementation allows multiple parallel streams of data to provide input to a heterogenous collection of simple operators whose interconnection form an algorithm. The local data flow control allows this device to execute algorithms extremely quickly provided that care is taken in the layout of the algorithm. I/O rates of several hundred megabytes/second are routinely achieved thus making DDP's attractive candidates for complex online calculations. The original question was open-quote can a DDP reconstruct tracks in a Silicon Vertex Detector, find events with a separated vertex and do it fast enough to be used as an online trigger?close-quote Restating this inquiry as three questions and describing the answers to the questions will be the subject of this talk. The three specific questions are: (1) Can an algorithm be found which reconstructs tracks in a planar geometry and no magnetic field; (2) Can separated vertices be recognized in some way; (3) Can the algorithm be implemented in the Nevis-UMass and DDP and execute in 10-20 μs?

  8. Status and prospects of the LHCb Vertex Locator

    CERN Document Server

    van Beuzekom, Martin

    2007-01-01

    The Vertex Locator of the LHCb experiment is a dedicated subdetector for the reconstruction of primary and secondary vertices in b-hadron decays. The vertex detector features two halves with 21 modules each, mounted on retractable bases. Each module consists of two half-disk silicon micro-strip sensors measuring hits in R and $\\Phi$ coordinates. The strip pitch ranges from 40 to about 100 $\\mu$m. A vacuum boy with a 300 $\\mu$m thick aluminium foil shields the sensors from the wakefields of the proton beams which are passing at a distance of 8 mm from the active area of the sensors. Because of the harsh non-uniform radiation environment we opted for n-on-n strips in diffusion oxygenated float zone silicon. The current status of the vertex detector, which has recently entered the commissioning phase, will be discussed. Given the limited lifetime of the detector due to the radiation environment, developments for a detector replacement with n-on-p type modules have already started. Possible upgrade scenarios fo...

  9. Charged Particle Tracking and Vertex Detection Group summary report

    International Nuclear Information System (INIS)

    Hanson, G.; Meyer, D.

    1984-09-01

    Charged particle tracking is essential in order to investigate the new physics expected at the SSC. The Tracking Group studied radiation damage and rate limitations to tracking devices, vertex detectors, and central tracking. The Group concluded that silicon strips and large wire tracking chambers with small cells can probably survive at the design luminosity of 10 33 cm -2 sec -1 ; however, the presently designed electronics for silicon strip vertex detectors can withstand a luminosity of only 10 31 cm -2 sec -1 . Wire chambers at a radius of less than about 25 cm can withstand a luminosity of less than or equal to 10 32 cm -2 sec -1 only. Actual tracking and pattern recognition in central tracking chambers at a luminosity of 10 33 cm -2 sec -1 will be very difficult because of multiple interactions within the resolving time of the chambers; detailed simulations are needed in order to decide whether tracking is indeed possible at this luminosity. Scintillating glass fibers are an interesting possibility both for vertex detectors and for central trackers, but much research and development is still needed both on the fibers themselves and on the readout

  10. Vertex and Tracker Research and Development for CLIC

    CERN Document Server

    Munker, M

    2017-01-01

    Challenging detector requirements are imposed by the physics goals at the future multi-TeV e+e− Compact Linear Collider (CLIC). A single point resolution of 3 μm for the vertex detector and 7 μm for the tracker is required. Moreover, the CLIC vertex detector and tracker need to be extremely light weighted with a material budget of 0.2%X0 per layer in the vertex detector and 1 - 2%X0 in the tracker. A fast time slicing of 10 ns is further required to suppress background from beam-beam interactions. A wide range of sensor and readout ASIC technologies are investigated within the CLIC silicon pixel R&D; effort. Various hybrid planar sensor assemblies with a pixel size of 25 × 25 μm2 and 55 × 55 μm2 have been produced and characterised by laboratory measurements and during test-beam campaigns. Experimental and simulation results for thin (50 μm- 500 μm) slim edge and active-edge planar, and High-Voltage CMOS sensors hybridised to various readout ASICs (Timepix, Timepix3, CLICpix) are presented.

  11. Colour-independent partition functions in coloured vertex models

    Energy Technology Data Exchange (ETDEWEB)

    Foda, O., E-mail: omar.foda@unimelb.edu.au [Dept. of Mathematics and Statistics, University of Melbourne, Parkville, VIC 3010 (Australia); Wheeler, M., E-mail: mwheeler@lpthe.jussieu.fr [Laboratoire de Physique Théorique et Hautes Energies, CNRS UMR 7589 (France); Université Pierre et Marie Curie – Paris 6, 4 place Jussieu, 75252 Paris cedex 05 (France)

    2013-06-11

    We study lattice configurations related to S{sub n}, the scalar product of an off-shell state and an on-shell state in rational A{sub n} integrable vertex models, n∈{1,2}. The lattice lines are colourless and oriented. The state variables are n conserved colours that flow along the line orientations, but do not necessarily cover every bond in the lattice. Choosing boundary conditions such that the positions where the colours flow into the lattice are fixed, and where they flow out are summed over, we show that the partition functions of these configurations, with these boundary conditions, are n-independent. Our results extend to trigonometric A{sub n} models, and to all n. This n-independence explains, in vertex-model terms, results from recent studies of S{sub 2} (Caetano and Vieira, 2012, [1], Wheeler, (arXiv:1204.2089), [2]). Namely, 1.S{sub 2}, which depends on two sets of Bethe roots, {b_1} and {b_2}, and cannot (as far as we know) be expressed in single determinant form, degenerates in the limit {b_1}→∞, and/or {b_2}→∞, into a product of determinants, 2. Each of the latter determinants is an A{sub 1} vertex-model partition function.

  12. Colour-independent partition functions in coloured vertex models

    International Nuclear Information System (INIS)

    Foda, O.; Wheeler, M.

    2013-01-01

    We study lattice configurations related to S n , the scalar product of an off-shell state and an on-shell state in rational A n integrable vertex models, n∈{1,2}. The lattice lines are colourless and oriented. The state variables are n conserved colours that flow along the line orientations, but do not necessarily cover every bond in the lattice. Choosing boundary conditions such that the positions where the colours flow into the lattice are fixed, and where they flow out are summed over, we show that the partition functions of these configurations, with these boundary conditions, are n-independent. Our results extend to trigonometric A n models, and to all n. This n-independence explains, in vertex-model terms, results from recent studies of S 2 (Caetano and Vieira, 2012, [1], Wheeler, (arXiv:1204.2089), [2]). Namely, 1.S 2 , which depends on two sets of Bethe roots, {b 1 } and {b 2 }, and cannot (as far as we know) be expressed in single determinant form, degenerates in the limit {b 1 }→∞, and/or {b 2 }→∞, into a product of determinants, 2. Each of the latter determinants is an A 1 vertex-model partition function

  13. Track and vertex reconstruction: From classical to adaptive methods

    International Nuclear Information System (INIS)

    Strandlie, Are; Fruehwirth, Rudolf

    2010-01-01

    This paper reviews classical and adaptive methods of track and vertex reconstruction in particle physics experiments. Adaptive methods have been developed to meet the experimental challenges at high-energy colliders, in particular, the CERN Large Hadron Collider. They can be characterized by the obliteration of the traditional boundaries between pattern recognition and statistical estimation, by the competition between different hypotheses about what constitutes a track or a vertex, and by a high level of flexibility and robustness achieved with a minimum of assumptions about the data. The theoretical background of some of the adaptive methods is described, and it is shown that there is a close connection between the two main branches of adaptive methods: neural networks and deformable templates, on the one hand, and robust stochastic filters with annealing, on the other hand. As both classical and adaptive methods of track and vertex reconstruction presuppose precise knowledge of the positions of the sensitive detector elements, the paper includes an overview of detector alignment methods and a survey of the alignment strategies employed by past and current experiments.

  14. The Belle silicon vertex detector Present performance and upgrade plans

    CERN Document Server

    Taylor, Geoffrey

    2003-01-01

    The Belle detector has been operating at the KEKB colliding beam B- factory since 1999. It is a general purpose detector optimized to measure decay products of BB over bar pairs created at the Y(4S) resonance. The vertexing function provided by the Silicon Vertex Detector (SVD) is crucial for accurate B-decay measurements, particularly in searching for asymmetries in decay times of B over bar and B mesons, the essence of CP violation being studied at Belle. High radiation levels during early KEKB running soon rendered "SVD1.0" inoperable. It was replaced by another of the same design, built in parallel with the installation of SVD1.0. Improvement of the beam operating conditions allowed "SVD1.1" to provide vertex information for the first year of operation. During this time "SVD1.4" was built. This was mechanically identical, so needed no new tooling or structure development but used a radiation tolerant 0.8mum process VA1 prime chip and an upgraded detector design from Hamamatsu. SVD1.4 was installed in Bell...

  15. Equilibrium sampling by reweighting nonequilibrium simulation trajectories.

    Science.gov (United States)

    Yang, Cheng; Wan, Biao; Xu, Shun; Wang, Yanting; Zhou, Xin

    2016-03-01

    Based on equilibrium molecular simulations, it is usually difficult to efficiently visit the whole conformational space of complex systems, which are separated into some metastable regions by high free energy barriers. Nonequilibrium simulations could enhance transitions among these metastable regions and then be applied to sample equilibrium distributions in complex systems, since the associated nonequilibrium effects can be removed by employing the Jarzynski equality (JE). Here we present such a systematical method, named reweighted nonequilibrium ensemble dynamics (RNED), to efficiently sample equilibrium conformations. The RNED is a combination of the JE and our previous reweighted ensemble dynamics (RED) method. The original JE reproduces equilibrium from lots of nonequilibrium trajectories but requires that the initial distribution of these trajectories is equilibrium. The RED reweights many equilibrium trajectories from an arbitrary initial distribution to get the equilibrium distribution, whereas the RNED has both advantages of the two methods, reproducing equilibrium from lots of nonequilibrium simulation trajectories with an arbitrary initial conformational distribution. We illustrated the application of the RNED in a toy model and in a Lennard-Jones fluid to detect its liquid-solid phase coexistence. The results indicate that the RNED sufficiently extends the application of both the original JE and the RED in equilibrium sampling of complex systems.

  16. Nonequilibrium molecular dynamics theory, algorithms and applications

    CERN Document Server

    Todd, Billy D

    2017-01-01

    Written by two specialists with over twenty-five years of experience in the field, this valuable text presents a wide range of topics within the growing field of nonequilibrium molecular dynamics (NEMD). It introduces theories which are fundamental to the field - namely, nonequilibrium statistical mechanics and nonequilibrium thermodynamics - and provides state-of-the-art algorithms and advice for designing reliable NEMD code, as well as examining applications for both atomic and molecular fluids. It discusses homogenous and inhomogenous flows and pays considerable attention to highly confined fluids, such as nanofluidics. In addition to statistical mechanics and thermodynamics, the book covers the themes of temperature and thermodynamic fluxes and their computation, the theory and algorithms for homogenous shear and elongational flows, response theory and its applications, heat and mass transport algorithms, applications in molecular rheology, highly confined fluids (nanofluidics), the phenomenon of slip and...

  17. Non-Equilibrium Thermodynamics in Multiphase Flows

    CERN Document Server

    Mauri, Roberto

    2013-01-01

    Non-equilibrium thermodynamics is a general framework that allows the macroscopic description of irreversible processes. This book introduces non-equilibrium thermodynamics and its applications to the rheology of multiphase flows. The subject is relevant to graduate students in chemical and mechanical engineering, physics and material science. This book is divided into two parts. The first part presents the theory of non-equilibrium thermodynamics, reviewing its essential features and showing, when possible, some applications. The second part of this book deals with how the general theory can be applied to model multiphase flows and, in particular, how to determine their constitutive relations. Each chapter contains problems at the end, the solutions of which are given at the end of the book. No prior knowledge of statistical mechanics is required; the necessary prerequisites are elements of transport phenomena and on thermodynamics. “The style of the book is mathematical, but nonetheless it remains very re...

  18. Nonequilibrium thermodynamics of restricted Boltzmann machines

    Science.gov (United States)

    Salazar, Domingos S. P.

    2017-08-01

    In this work, we analyze the nonequilibrium thermodynamics of a class of neural networks known as restricted Boltzmann machines (RBMs) in the context of unsupervised learning. We show how the network is described as a discrete Markov process and how the detailed balance condition and the Maxwell-Boltzmann equilibrium distribution are sufficient conditions for a complete thermodynamics description, including nonequilibrium fluctuation theorems. Numerical simulations in a fully trained RBM are performed and the heat exchange fluctuation theorem is verified with excellent agreement to the theory. We observe how the contrastive divergence functional, mostly used in unsupervised learning of RBMs, is closely related to nonequilibrium thermodynamic quantities. We also use the framework to interpret the estimation of the partition function of RBMs with the annealed importance sampling method from a thermodynamics standpoint. Finally, we argue that unsupervised learning of RBMs is equivalent to a work protocol in a system driven by the laws of thermodynamics in the absence of labeled data.

  19. Nonequilibrium statistical physics a modern perspective

    CERN Document Server

    Livi, Roberto

    2017-01-01

    Statistical mechanics has been proven to be successful at describing physical systems at thermodynamic equilibrium. Since most natural phenomena occur in nonequilibrium conditions, the present challenge is to find suitable physical approaches for such conditions: this book provides a pedagogical pathway that explores various perspectives. The use of clear language, and explanatory figures and diagrams to describe models, simulations and experimental findings makes the book a valuable resource for undergraduate and graduate students, and also for lecturers organizing teaching at varying levels of experience in the field. Written in three parts, it covers basic and traditional concepts of nonequilibrium physics, modern aspects concerning nonequilibrium phase transitions, and application-orientated topics from a modern perspective. A broad range of topics is covered, including Langevin equations, Levy processes, directed percolation, kinetic roughening and pattern formation.

  20. Non-equilibrium and band tailing in organic conductors

    Indian Academy of Sciences (India)

    . Non-equilibrium due to coupling between applied energy and free electrons can be responsible for the exponential relaxation from non-equilibrium to equilibrium. Keywords. Band tailing; organic conductors; IR spectra; electrical resistivity.

  1. Thermodynamic model of nonequilibrium phase transitions.

    Science.gov (United States)

    Martyushev, L M; Konovalov, M S

    2011-07-01

    Within the scope of a thermodynamic description using the maximum entropy production principle, transitions from one nonequilibrium (kinetic) regime to another are considered. It is shown that in the case when power-law dependencies of thermodynamic flux on force are similar for two regimes, only a transition accompanied by a positive jump of thermodynamic flux is possible between them. It is found that the difference in powers of the dependencies of thermodynamic fluxes on forces results in a number of interesting nonequilibrium transitions between kinetic regimes, including the reentrant one with a negative jump of thermodynamic flux.

  2. Canonical operator formulation of nonequilibrium thermodynamics

    International Nuclear Information System (INIS)

    Mehrafarin, M.

    1992-09-01

    A novel formulation of nonequilibrium thermodynamics is proposed which emphasises the fundamental role played by the Boltzmann constant k in fluctuations. The equivalence of this and the stochastic formulation is demonstrated. The k → 0 limit of this theory yields the classical deterministic description of nonequilibrium thermodynamics. The new formulation possesses unique features which bear two important results namely the thermodynamic uncertainty principle and the quantisation of entropy production rate. Such a theory becomes indispensable whenever fluctuations play a significant role. (author). 7 refs

  3. Nonideal plasmas as non-equilibrium media

    International Nuclear Information System (INIS)

    Morozov, I V; Norman, G E; Valuev, A A; Valuev, I A

    2003-01-01

    Various aspects of the collective behaviour of non-equilibrium nonideal plasmas are studied. The relaxation of kinetic energy to the equilibrium state is simulated by the molecular dynamics (MD) method for two-component non-degenerate strongly non-equilibrium plasmas. The initial non-exponential stage, its duration and the subsequent exponential stage of the relaxation process are studied for a wide range of ion charge, nonideality parameter and ion mass. A simulation model of the nonideal plasma excited by an electron beam is proposed. An approach is developed to calculate the dynamic structure factor in non-stationary conditions. Instability increment is obtained from MD simulations

  4. On the excess energy of nonequilibrium plasma

    International Nuclear Information System (INIS)

    Timofeev, A. V.

    2012-01-01

    The energy that can be released in plasma due to the onset of instability (the excess plasma energy) is estimated. Three potentially unstable plasma states are considered, namely, plasma with an anisotropic Maxwellian velocity distribution of plasma particles, plasma with a two-beam velocity distribution, and an inhomogeneous plasma in a magnetic field with a local Maxwellian velocity distribution. The excess energy can serve as a measure of the degree to which plasma is nonequilibrium. In particular, this quantity can be used to compare plasmas in different nonequilibrium states.

  5. Counting surface-kernel epimorphisms from a co-compact Fuchsian group to a cyclic group with motivations from string theory and QFT

    Directory of Open Access Journals (Sweden)

    Khodakhast Bibak

    2016-09-01

    Full Text Available Graphs embedded into surfaces have many important applications, in particular, in combinatorics, geometry, and physics. For example, ribbon graphs and their counting is of great interest in string theory and quantum field theory (QFT. Recently, Koch et al. (2013 [12] gave a refined formula for counting ribbon graphs and discussed its applications to several physics problems. An important factor in this formula is the number of surface-kernel epimorphisms from a co-compact Fuchsian group to a cyclic group. The aim of this paper is to give an explicit and practical formula for the number of such epimorphisms. As a consequence, we obtain an ‘equivalent’ form of Harvey's famous theorem on the cyclic groups of automorphisms of compact Riemann surfaces. Our main tool is an explicit formula for the number of solutions of restricted linear congruence recently proved by Bibak et al. using properties of Ramanujan sums and of the finite Fourier transform of arithmetic functions.

  6. Intrinsic-normal-ordered vertex operators from the multiloop N-tachyon amplitude

    International Nuclear Information System (INIS)

    Aldazabal, G.; Nunez, C.; Bonini, M.; Iengo, R.

    1987-09-01

    We construct vertex operators for arbitrary mass level states of the closed bosonic string. Starting from a generalization of the Koba-Nielsen amplitude which is suitable for an arbitrary genus Riemann surface, we read the vertex operators from the residues of the poles for the intermediate states. Since the original expression is metric independent and normal ordered without the need of inventing any regularization scheme, our vertex operators also possess these properties. We discuss their general features. (author). 17 refs

  7. Three-coloring graphs with no induced seven-vertex path II : using a triangle

    OpenAIRE

    Chudnovsky, Maria; Maceli, Peter; Zhong, Mingxian

    2015-01-01

    In this paper, we give a polynomial time algorithm which determines if a given graph containing a triangle and no induced seven-vertex path is 3-colorable, and gives an explicit coloring if one exists. In previous work, we gave a polynomial time algorithm for three-coloring triangle-free graphs with no induced seven-vertex path. Combined, our work shows that three-coloring a graph with no induced seven-vertex path can be done in polynomial time.

  8. cellGPU: Massively parallel simulations of dynamic vertex models

    Science.gov (United States)

    Sussman, Daniel M.

    2017-10-01

    Vertex models represent confluent tissue by polygonal or polyhedral tilings of space, with the individual cells interacting via force laws that depend on both the geometry of the cells and the topology of the tessellation. This dependence on the connectivity of the cellular network introduces several complications to performing molecular-dynamics-like simulations of vertex models, and in particular makes parallelizing the simulations difficult. cellGPU addresses this difficulty and lays the foundation for massively parallelized, GPU-based simulations of these models. This article discusses its implementation for a pair of two-dimensional models, and compares the typical performance that can be expected between running cellGPU entirely on the CPU versus its performance when running on a range of commercial and server-grade graphics cards. By implementing the calculation of topological changes and forces on cells in a highly parallelizable fashion, cellGPU enables researchers to simulate time- and length-scales previously inaccessible via existing single-threaded CPU implementations. Program Files doi:http://dx.doi.org/10.17632/6j2cj29t3r.1 Licensing provisions: MIT Programming language: CUDA/C++ Nature of problem: Simulations of off-lattice "vertex models" of cells, in which the interaction forces depend on both the geometry and the topology of the cellular aggregate. Solution method: Highly parallelized GPU-accelerated dynamical simulations in which the force calculations and the topological features can be handled on either the CPU or GPU. Additional comments: The code is hosted at https://gitlab.com/dmsussman/cellGPU, with documentation additionally maintained at http://dmsussman.gitlab.io/cellGPUdocumentation

  9. Non-equilibrium thermodynamics and physical kinetics

    CERN Document Server

    Bikkin, Halid

    2014-01-01

    This graduate textbook covers contemporary directions of non-equilibrium statistical mechanics as well as classical methods of kinetics. With one of the main propositions being to avoid terms such as "obviously" and "it is easy to show", this treatise is an easy-to-read introduction into this traditional, yet vibrant field.

  10. Modeling interfacial dynamics using nonequilibrium thermodynamics frameworks

    NARCIS (Netherlands)

    Sagis, L.M.C.

    2013-01-01

    In recent years several nonequilibrium thermodynamic frameworks have been developed capable of describing the dynamics of multiphase systems with complex microstructured interfaces. In this paper we present an overview of these frameworks. We will discuss interfacial dynamics in the context of the

  11. Non-equilibrium modelling of distillation

    NARCIS (Netherlands)

    Wesselingh, JA; Darton, R

    1997-01-01

    There are nasty conceptual problems in the classical way of describing distillation columns via equilibrium stages, and efficiencies or HETP's. We can nowadays avoid these problems by simulating the behaviour of a complete column in one go using a non-equilibrium model. Such a model has phase

  12. Evolution and non-equilibrium physics

    DEFF Research Database (Denmark)

    Becker, Nikolaj; Sibani, Paolo

    2014-01-01

    We argue that the stochastic dynamics of interacting agents which replicate, mutate and die constitutes a non-equilibrium physical process akin to aging in complex materials. Specifically, our study uses extensive computer simulations of the Tangled Nature Model (TNM) of biological evolution...

  13. Three-point vertex functions in Yang-Mills Theory and QCD in Landau gauge

    Science.gov (United States)

    Blum, Adrian L.; Alkofer, Reinhard; Huber, Markus Q.; Windisch, Andreas

    2017-03-01

    Solutions for the three-gluon and quark-gluon vertices from Dyson-Schwinger equations and the three-particle irreducible formalism are discussed. Dynamical quarks ("unquenching") change the three-gluon vertex via the quark-triangle diagrams which themselves include fully dressed quark-gluon vertex functions. On the other hand, the quark-swordfish diagram is, at least with the model used for the two-quark-two-gluon vertex employed here, of minor importance. For the leading tensor structure of the threegluon vertex the "unquenching" effect can be summarized for the nonperturbative part as a shift of the related dressing function towards the infrared.

  14. Strings in background fields: β functions and vertex operators

    International Nuclear Information System (INIS)

    de Alwis, S.P.

    1986-01-01

    We review the conditions for consistent propagation of closed strings in background fields and discuss the connection between conformal invariance and the vanishing of the renormalization-group β functions for the generalized σ model on a curved world sheet. The β functions with up to four derivative terms are found to be compatible with graviton and dilaton equations of motion provided the former are computed in a nonminimal subtraction scheme. Finally, vertex operators in background fields are discussed and it is shown that the anomalous dimension operator is given by the first variation of the β function to all orders in α'

  15. A new tool for constrained vertex fitting in ATLAS

    CERN Document Server

    Colijn, Auke Pieter; Limper, Maaike; Prokofiev, Kirill

    2009-01-01

    The precise reconstruction of trajectories of charged and neutral particles and their decay vertices is crucial for many physics analyses. Studying the tracking performance on well known benchmark channels helps to understand the properties of the ATLAS detector during the initial phase of the LHC. In order to exploit the correlations between reconstructed parameters of final state tracks having the same mother particle, a new tool for vertex fitting with possibility of simultaneous application of kinematic constraints has been developed. Using this tool on a benchmark channel such as J/psi to μ+μ− helps to correct shifts in the reconstructed curvature induced by systematic deformations of the detector.

  16. Ionization potentials of solids: the importance of vertex corrections.

    Science.gov (United States)

    Grüneis, Andreas; Kresse, Georg; Hinuma, Yoyo; Oba, Fumiyasu

    2014-03-07

    The ionization potential is a fundamental key quantity with great relevance to diverse material properties. We find that state of the art methods based on density functional theory and simple diagrammatic approaches as commonly taken in the GW approximation predict the ionization potentials of semiconductors and insulators unsatisfactorily. Good agreement between theory and experiment is obtained only when diagrams resulting from the antisymmetry of the many-electron wave function are taken into account via vertex corrections in the self-energy. The present approach describes both localized and delocalized states accurately, making it ideally suited for a wide class of materials and processes.

  17. Capacitively coupled hybrid pixel assemblies for the CLIC vertex detector

    OpenAIRE

    Alipour Tehrani, Niloufar; Arfaoui, Samir; Benoit, Mathieu; Dannheim, Dominik; Dette, Karola; Hynds, Daniel; Kulis, Szymon; Peric, Ivan; Petric, Marko; Redford, Sophie; Sicking, Eva; Valerio, Pierpaolo

    2016-01-01

    The vertex detector at the proposed CLIC multi-TeV linear e+e- collider must have minimal material content and high spatial resolution, combined with accurate time-stamping to cope with the expected high rate of beam-induced backgrounds. One of the options being considered is the use of active sensors implemented in a commercial high-voltage CMOS process, capacitively coupled to hybrid pixel ASICs. A prototype of such an assembly, using two custom designed chips (CCPDv3 as active sensor glued...

  18. 3D circuit integration for Vertex and other detectors

    Energy Technology Data Exchange (ETDEWEB)

    Yarema, Ray; /Fermilab

    2007-09-01

    High Energy Physics continues to push the technical boundaries for electronics. There is no area where this is truer than for vertex detectors. Lower mass and power along with higher resolution and radiation tolerance are driving forces. New technologies such as SOI CMOS detectors and three dimensional (3D) integrated circuits offer new opportunities to meet these challenges. The fundamentals for SOI CMOS detectors and 3D integrated circuits are discussed. Examples of each approach for physics applications are presented. Cost issues and ways to reduce development costs are discussed.

  19. Vertex Normals and Face Curvatures of Triangle Meshes

    KAUST Repository

    Sun, Xiang

    2016-08-12

    This study contributes to the discrete differential geometry of triangle meshes, in combination with discrete line congruences associated with such meshes. In particular we discuss when a congruence defined by linear interpolation of vertex normals deserves to be called a ʼnormal’ congruence. Our main results are a discussion of various definitions of normality, a detailed study of the geometry of such congruences, and a concept of curvatures and shape operators associated with the faces of a triangle mesh. These curvatures are compatible with both normal congruences and the Steiner formula.

  20. Eight-Vertex Model of Two-Dimensional Domain Walls

    Science.gov (United States)

    Rys, Franz S.

    1983-09-01

    A statistical model of interacting linear domain walls (occurring, e.g., in monolayer adsorbates) is solved on the square lattice with use of exact and numerical results of an equivalent eight-vertex model. For attractive walls a commensurate and an incommensurate phase are separated by a first-order line for stiff walls and by a fluid phase for flexible walls. The phase boundaries with the fluid phase are Ising-like. For repulsive stiff walls an intermediate striped phase with a nonuniversal boundary occurs which vanishes for higher flexibilities. Moreover, disorder lines are located.

  1. A NEW HYBRID GENETIC ALGORITHM FOR VERTEX COVER PROBLEM

    OpenAIRE

    UĞURLU, Onur

    2015-01-01

    The minimum vertex cover  problem belongs to the  class  of  NP-compl ete  graph  theoretical problems. This paper presents a hybrid genetic algorithm to solve minimum ver tex cover problem. In this paper, it has been shown that when local optimization technique is added t o genetic algorithm to form hybrid genetic algorithm, it gives more quality solution than simple genet ic algorithm. Also, anew mutation operator has been developed especially for minimum verte...

  2. Performance of the VTL PEPR vertex guidance system

    International Nuclear Information System (INIS)

    Dunn, L.A.; Harris, R.; Kenyon, R.G.; Lubatti, H.J.; Moriyasu, K.

    1975-01-01

    A PEPR vertex guidance system requiring no operator intervention has been operating at the University of Washington's Visual Techniques Laboratory since 1972. The measurement of 140 000 events consisting of 3, 4, 5, and 6-prong interactions of a 15 GeV/c π - beam with deuterium was recently completed. The system employs global transformations that reduce circular tracks to a point in a two-dimensional angle-curvature space. Noise reduction techniques are used to improve position and angle accuracy and thereby the system resolution and efficiency. Monitoring criteria were developed to ensure continuous peak performance over long production periods. (Auth.)

  3. Performance of the CLAS12 Silicon Vertex Tracker modules

    Energy Technology Data Exchange (ETDEWEB)

    Antonioli, M.A.; Boiarinov, S.; Bonneau, P.; Elouadrhiri, L.; Eng, B. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Gotra, Y., E-mail: gotra@jlab.org [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Kurbatov, E. [Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow (Russian Federation); Leffel, M.; Mandal, S.; McMullen, M. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Merkin, M. [Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow (Russian Federation); Raydo, B.; Teachey, W. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Tucker, R. [Arizona State University, Tempe, AZ (United States); Ungaro, M.; Yegneswaran, A.; Ziegler, V. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2013-12-21

    For the 12 GeV upgrade, the CLAS12 experiment has designed a Silicon Vertex Tracker (SVT) using single sided microstrip sensors fabricated by Hamamatsu. The sensors have graded angle design to minimize dead areas and a readout pitch of 156μm, with intermediate strip. Double sided SVT module hosts three daisy-chained sensors on each side with a full strip length of 33 cm. There are 512 channels per module read out by four Fermilab Silicon Strip Readout (FSSR2) chips featuring data driven architecture, mounted on a rigid-flex hybrid. Modules are assembled on the barrel using unique cantilevered geometry to minimize the amount of material in the tracking volume. Design and performance of the SVT modules are presented, focusing on results of electrical measurements. -- Highlights: •A Silicon Vertex Tracker has been designed for the central tracker of the CLAS12 experiment. •Using cantilevered module geometry allows minimizing amount of material in the tracking volume. •A dedicated Hybrid Flex Circuit Board has been developed to read out double sided module. •Module performance meets design goals of the CLAS12 Central Tracker.

  4. Stochastic Higher Spin Vertex Models on the Line

    Science.gov (United States)

    Corwin, Ivan; Petrov, Leonid

    2016-04-01

    We introduce a four-parameter family of interacting particle systems on the line, which can be diagonalized explicitly via a complete set of Bethe ansatz eigenfunctions, and which enjoy certain Markov dualities. Using this, for the systems started in step initial data, we write down nested contour integral formulas for moments and Fredholm determinant formulas for Laplace-type transforms. Taking various choices or limits of parameters, this family degenerates to many of the known exactly solvable models in the Kardar-Parisi-Zhang universality class, as well as leads to many new examples of such models. In particular, asymmetric simple exclusion process, the stochastic six-vertex model, q-totally asymmetric simple exclusion process and various directed polymer models all arise in this manner. Our systems are constructed from stochastic versions of the R-matrix related to the six-vertex model. One of the key tools used here is the fusion of R-matrices and we provide a probabilistic proof of this procedure.

  5. Vertex function representation in non-uniform frequency grids

    Science.gov (United States)

    Tam, Ka-Ming; Yang, Shuxiang; Moreno, Juana; Jarrell, Mark

    2014-03-01

    The proper computer representation of many-body vertex functions is a central issue in computational many body methods such as the parquet formalism, a self-consistent two-particle field theory. Despite the great effort over the past two decades, its application is very limited. This is predominately due to two crucial factors - the stability of the iteration and the size of the memory allocation for the vertices. We previously demonstrated that the stability problem can be alleviated by explicitly restoring the crossing symmetry, making simulations beyond weak coupling for the Hubbard model feasible. The next step for the practical applications of the parquet formalism is to compress the memory required to represent the vertex. In this talk, we first demonstrate the problem of perturbation theory off the Matsubara frequency grids. This problem is avoided by working on the so-called decimation grids, which are non-uniform grids on Matsubara frequency. We then use this scheme in the parquet method, for solving an Anderson impurity problem. The results show substantial improvement compared to using the same number of uniform frequency grids. This may represent a crucial step towards practical applications of the parquet formalism for large clusters.

  6. Nonperturbative aspects of the quark-photon vertex

    International Nuclear Information System (INIS)

    The electromagnetic interaction with quarks is investigated through a relativistic, electromagnetic gauge-invariant treatment. Gluon dressing of the quark-photon vertex and the quark self-energy functions is described by the inhomogeneous Bethe-Salpeter equation in the ladder approximation and the Schwinger-Dyson equation in the rainbow approximation respectively. Results for the calculation of the quark-photon vertex are presented in both the time-like and space-like regions of photon momentum squared, however emphasis is placed on the space-like region relevant to electron scattering. The treatment presented here simultaneously addresses the role of dynamically generated q bar q vector bound states and the approach to asymptotic behavior. The resulting description is therefore applicable over the entire range of momentum transfers available in electron scattering experiments. Input parameters are limited to the model gluon two-point function which is chosen to reflect confinement and asymptotic freedom and are largely constrained by the obtained bound-state spectrum

  7. SPARTex: A Vertex-Centric Framework for RDF Data Analytics

    KAUST Repository

    Abdelaziz, Ibrahim

    2015-08-31

    A growing number of applications require combining SPARQL queries with generic graph search on RDF data. However, the lack of procedural capabilities in SPARQL makes it inappropriate for graph analytics. Moreover, RDF engines focus on SPARQL query evaluation whereas graph management frameworks perform only generic graph computations. In this work, we bridge the gap by introducing SPARTex, an RDF analytics framework based on the vertex-centric computation model. In SPARTex, user-defined vertex centric programs can be invoked from SPARQL as stored procedures. SPARTex allows the execution of a pipeline of graph algorithms without the need for multiple reads/writes of input data and intermediate results. We use a cost-based optimizer for minimizing the communication cost. SPARTex evaluates queries that combine SPARQL and generic graph computations orders of magnitude faster than existing RDF engines. We demonstrate a real system prototype of SPARTex running on a local cluster using real and synthetic datasets. SPARTex has a real-time graphical user interface that allows the participants to write regular SPARQL queries, use our proposed SPARQL extension to declaratively invoke graph algorithms or combine/pipeline both SPARQL querying and generic graph analytics.

  8. Study of the Wtb vertex structure at the ATLAS experiment

    CERN Document Server

    AUTHOR|(CDS)2069592; Onofre, Antonio

    2008-01-01

    The top quark is the heaviest and least studied quark of the Standard Model. Although its properties have already been investigated at colliders, the statistics of the collected data have not yet allowed for precise measurements, with exception of its mass. The determination of other fundamental properties such as its couplings requires larger top quark samples, which will be available at the Large Hadron Collider (LHC) at CERN. Within the Standard Model, the Wtb vertex is purely left-handed, and its amplitude is given by the Cabibbo-Kobayashi-Maskawa matrix element Vtb, related to weak interaction between a top and a b-quark. In a more general way, additional anomalous couplings such as right-handed vectorial couplings and left and right-handed tensorial couplings can also be considered. The study of the angular distribution of the top quark decay products at the LHC will allow precision measurements of the structure of the Wtb vertex, providing also an important probe for possible physics beyond the SM. In ...

  9. The Mark II vertex detectors: Status and prospects

    International Nuclear Information System (INIS)

    Jaros, J.A.

    1987-03-01

    The art of detecting the decay vertices from heavy quarks and leptons is comparatively new at electron-positron storage rings. So far, drift chambers positioned just outside the vacuum pipes which surround the interfaction region have provided the first accurate determinations of the tau and bottom lifetimes, and confirmed earlier measurements of charmed particle lifetimes. ''Second generation'' vertex detectors have demonstrated the feasibility of tagging heavy flavors by observing decay vertices, and are being used to search for anomalous decay topologies. These chambers have modest resolution on the scale of the effects they seek to measure, but are now well-understood and reliable tools. A generation of vertex detectors, considerably more ambitious, is under construction for experiments at SLC and LEP. They boast impact parameter resolution improved by a factor of four or more over previous detectors, and sub-millimeter track-pair resolution. The Mark II collaboration hopes to reach these goals with a high pressure precision drift chamber, and eventually surpass them with the addition of a silicon microstrip detector

  10. The Mark II vertex detectors: Status and prospects

    Energy Technology Data Exchange (ETDEWEB)

    Jaros, J.A.

    1987-03-01

    The art of detecting the decay vertices from heavy quarks and leptons is comparatively new at electron-positron storage rings. So far, drift chambers positioned just outside the vacuum pipes which surround the interfaction region have provided the first accurate determinations of the tau and bottom lifetimes, and confirmed earlier measurements of charmed particle lifetimes. ''Second generation'' vertex detectors have demonstrated the feasibility of tagging heavy flavors by observing decay vertices, and are being used to search for anomalous decay topologies. These chambers have modest resolution on the scale of the effects they seek to measure, but are now well-understood and reliable tools. A generation of vertex detectors, considerably more ambitious, is under construction for experiments at SLC and LEP. They boast impact parameter resolution improved by a factor of four or more over previous detectors, and sub-millimeter track-pair resolution. The Mark II collaboration hopes to reach these goals with a high pressure precision drift chamber, and eventually surpass them with the addition of a silicon microstrip detector.

  11. A momentum space analysis of the Triple Pomeron Vertex in pQCD

    Energy Technology Data Exchange (ETDEWEB)

    Bartels, J. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Kutak, K. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)]|[Instytut Fizyki Jadrowej Polskiej Akademii Nauk, Krakow (Poland)

    2007-10-15

    We study properties of the momentum space Triple Pomeron Vertex in perturbative QCD. Particular attention is given to the collinear limit where transverse momenta on one side of the vertex are much larger than on the other side. We also comment on the kernels in nonlinear evolution equations. (orig.)

  12. A quantum relativistic integrable model as the continuous limit of the six-vertex model

    International Nuclear Information System (INIS)

    Zhou, Y.K.

    1992-01-01

    The six-vertex model in two-dimensional statistical mechanics is used to construct the L-matrix of a one-dimensional quantum relativistic integrable model through a continuous limit. This is the first step to extend the method used earlier by the author to construct quantum completely integrable systems from other well-known two-dimensional vertex models. (orig.)

  13. A vertex including emission of spin fields for an arbitrary bc system

    International Nuclear Information System (INIS)

    Di Vecchia, P.; Madsen, R.A.; Roland, K.

    1990-01-01

    We construct the (N+2M) Point Vertex involving the emission of N Neveu-Schwarz and 2M Ramond states for a bosonic and fermionic bc system with a bockground charge Q. From it one can compute correlation functions on the sphere involving any number of spin fields. We show in detail that the vertex satisfies overlap conditions. (orig.)

  14. Quantum nonequilibrium equalities with absolute irreversibility

    Science.gov (United States)

    Funo, Ken; Murashita, Yûto; Ueda, Masahito

    2015-07-01

    We derive quantum nonequilibrium equalities in absolutely irreversible processes. Here by absolute irreversibility we mean that in the backward process the density matrix does not return to the subspace spanned by those eigenvectors that have nonzero weight in the initial density matrix. Since the initial state of a memory and the postmeasurement state of the system are usually restricted to a subspace, absolute irreversibility occurs during the measurement and feedback processes. An additional entropy produced in absolutely irreversible processes needs to be taken into account to derive nonequilibrium equalities. We discuss a model of a feedback control on a qubit system to illustrate the obtained equalities. By introducing N heat baths each composed of a qubit and letting them interact with the system, we show how the entropy reduction via feedback control can be converted into work. An explicit form of extractable work in the presence of absolute irreversibility is given.

  15. The scalar-photon 3-point vertex in massless quenched scalar QED

    International Nuclear Information System (INIS)

    Concha-Sánchez, Y; Gutiérrez-Guerrero, L X; Fernández-Rangel, L A

    2016-01-01

    Non perturbative studies of Schwinger-Dyson equations (SDEs) require their infinite, coupled tower to be truncated in order to reduce them to a practically solvable set. In this connection, a physically acceptable ansatz for the three point vertex is the most favorite choice. Scalar quantum electrodynamics (sQED) provides a simple and neat platform to address this problem. The most general form of the scalar-photon three point vertex can be expressed in terms of only two independent form factors, longitudinal and transverse. Ball and Chiu have demonstrated that the longitudinal vertex is fixed by requiring the Ward-Fradkin-Green- Takahashi identity (WFGTI), while the transverse vertex remains undetermined. In massless quenched sQED, we propose the transverse part of the non perturbative scalar-photon vertex. (paper)

  16. A quantum hybrid with a thin antenna at the vertex of a wedge

    Energy Technology Data Exchange (ETDEWEB)

    Carlone, Raffaele, E-mail: raffaele.carlone@unina.it [Università “Federico II” di Napoli, Dipartimento di Matematica e Applicazioni “R. Caccioppoli”, MSA, via Cinthia, I-80126, Napoli (Italy); Posilicano, Andrea, E-mail: andrea.posilicano@uninsubria.it [DiSAT, Università dell' Insubria, via Valleggio 11, I-22100, Como (Italy)

    2017-03-26

    We study the spectrum, resonances and scattering matrix of a quantum Hamiltonian on a “hybrid surface” consisting of a half-line attached by its endpoint to the vertex of a concave planar wedge. At the boundary of the wedge, outside the vertex, homogeneous Dirichlet conditions are imposed. The system is tunable by varying the measure of the angle at the vertex. - Highlights: • Spectral characterization of a quantum Hamiltonian on “hybrid surface” consisting of a halfline attached to the vertex of a concave planar wedge. • The system is tunable by varying the measure of the angle at the vertex. • Relation between the conduction properties inside the hybrid and formation of resonances. • Easy generalization of the results to more complicated structures.

  17. Lattice Boltzmann approach for complex nonequilibrium flows.

    Science.gov (United States)

    Montessori, A; Prestininzi, P; La Rocca, M; Succi, S

    2015-10-01

    We present a lattice Boltzmann realization of Grad's extended hydrodynamic approach to nonequilibrium flows. This is achieved by using higher-order isotropic lattices coupled with a higher-order regularization procedure. The method is assessed for flow across parallel plates and three-dimensional flows in porous media, showing excellent agreement of the mass flow with analytical and numerical solutions of the Boltzmann equation across the full range of Knudsen numbers, from the hydrodynamic regime to ballistic motion.

  18. Low temperature behavior of nonequilibrium multilevel systems

    Czech Academy of Sciences Publication Activity Database

    Maes, C.; Netočný, Karel; O'Kelly de Galway, W.

    2014-01-01

    Roč. 47, č. 3 (2014), "035002-1"-"035002-11" ISSN 1751-8113 R&D Projects: GA ČR GAP204/12/0897 Institutional support: RVO:68378271 Keywords : nonequilibrium state state * low temperature Subject RIV: BE - Theoretical Physics Impact factor: 1.583, year: 2014 http://iopscience.iop.org/1751-8121/47/3/035002?fromSearchPage=true

  19. Equilibrium and nonequilibrium behaviour of surfactant systems

    OpenAIRE

    Reissig, Louisa

    2010-01-01

    In binary systems, surfactant molecules can self-assemble into a large variety of structures depending on their chemical structure, concentration and temperature. The properties and stability of the phases, their coexistence regions and the formation of metastable structures is of great importance not only for fundamental understanding, but also for applications in many fields including industry and medicine. This thesis presents studies of the equilibrium and non-equilibrium b...

  20. Improvements to a nonequilibrium algebraic turbulence model

    Science.gov (United States)

    Johnson, D. A.; Coakley, T. J.

    1990-01-01

    It has been noted that while the nonequilibrium turbulence model of Johnson and King (1985, 1987) performed significantly better than alternative methods, differences between predicted and observed shock locations for certain weak interactions are produced due to a defficiency in the model's inner eddy viscosity formulation. A novel formulation for the model is presented which removes this deficiency, while satisfying the law of the wall for adverse pressure-gradient conditions better than either the original formulation or mixing-length theory.

  1. Nonequilibrium functional bosonization of quantum wire networks

    Energy Technology Data Exchange (ETDEWEB)

    Ngo Dinh, Stephane, E-mail: stephane.ngodinh@kit.edu [Institut fuer Theorie der Kondensierten Materie, Karlsruhe Institute of Technology, 76128 Karlsruhe (Germany); DFG Center for Functional Nanostructures, Karlsruhe Institute of Technology, 76128 Karlsruhe (Germany); Bagrets, Dmitry A. [Institut fuer Theoretische Physik, Universitaet zu Koeln, Zuelpicher Str. 77, 50937 Koeln (Germany); Mirlin, Alexander D. [Institut fuer Theorie der Kondensierten Materie, Karlsruhe Institute of Technology, 76128 Karlsruhe (Germany); Institut fuer Nanotechnologie, Karlsruhe Institute of Technology, 76021 Karlsruhe (Germany); DFG Center for Functional Nanostructures, Karlsruhe Institute of Technology, 76128 Karlsruhe (Germany); Petersburg Nuclear Physics Institute, 188300 St. Petersburg (Russian Federation)

    2012-11-15

    We develop a general approach to nonequilibrium nanostructures formed by one-dimensional channels coupled by tunnel junctions and/or by impurity scattering. The formalism is based on nonequilibrium version of functional bosonization. A central role in this approach is played by the Keldysh action that has a form reminiscent of the theory of full counting statistics. To proceed with evaluation of physical observables, we assume the weak-tunneling regime and develop a real-time instanton method. A detailed exposition of the formalism is supplemented by two important applications: (i) tunneling into a biased Luttinger liquid with an impurity, and (ii) quantum Hall Fabry-Perot interferometry. - Highlights: Black-Right-Pointing-Pointer A nonequilibrium functional bosonization framework for quantum wire networks is developed Black-Right-Pointing-Pointer For the study of observables in the weak tunneling regime a real-time instanton method is elaborated. Black-Right-Pointing-Pointer We consider tunneling into a biased Luttinger liquid with an impurity. Black-Right-Pointing-Pointer We analyze electronic Fabry-Perot interferometers in the integer quantum Hall regime.

  2. Power pulsing schemes for vertex detectors at CLIC

    CERN Document Server

    Blanchot, G

    2013-01-01

    The precision requirements of the vertex detector at CLIC impose strong limitations on the mass of such a detector ( < 0.2% of a radiation length, Xo, per layer). To achieve such a low mass, ultra-thin hybrid pixel detectors are foreseen, while the mass for cooling and services will be reduced by implementing a power-pulsing scheme that takes advantage of the low duty cycle of the accelerator. The principal aim is to achieve significant power reduction without compromising the power integrity supplied to the front-end electronics. A power-pulsing scheme is proposed for the analog electronics and its electrical features are discussed on the basis of measurements.

  3. The Small Acceptance Vertex Detector of NA61/SHINE

    Directory of Open Access Journals (Sweden)

    Deveaux M.

    2018-01-01

    Full Text Available Charmonium production in heavy ion collisions is considered as an important diagnostic probe for studying the phase diagram of strongly interacting matter for potential phase transitions. The interpretation of existing data from the CERN SPS is hampered by a lack of knowledge on the properties of open charm particle production in the fireball. Moreover, open charm production in heavy ion collisions by itself is poorly understood. To overcome this obstacle, the NA61/SHINE was equipped with a Small Acceptance Vertex Detector (SAVD, which is predicted to make the experiment sensitive to open charm mesons produced in A-A collisions at the SPS top energy. This paper will introduce the concept and the hardware of the SAVD. Moreover, first running experience as obtained in a commissioning run with a 150 AGeV/c Pb+Pb collision system will be reported.

  4. Performance of the CLAS12 Silicon Vertex Tracker modules

    Energy Technology Data Exchange (ETDEWEB)

    Antonioli, Mary Ann [JLAB; Boiarinov, Serguie; Bonneau, Peter R. [JLAB; Elouadrhiri, Latifa [JLAB; Eng, Brian J. [JLAB; Gotra, Yuri N. [JLAB; Kurbatov, Evgeny O. [Moscow State U.; Leffel, Mindy A. [JLAB; Mandal, Saptarshi [JLAB; McMullen, Marc E. [JLAB; Merkin, Mikhail M. [Moscow State U.; Raydo, Benjamin J. [JLAB; Teachey, Robert W, [JLAB; Tucker, Ross J. [Arizona State U.; Ungaro, Maurizio [JLAB; Yegneswaran, Amrit S. [JLAB; Ziegler, Veronique [JLAB

    2013-12-01

    For the 12 GeV upgrade, the CLAS12 experiment has designed a Silicon Vertex Tracker (SVT) using single sided microstrip sensors fabricated by Hamamatsu. The sensors have graded angle design to minimize dead areas and a readout pitch of 156{micro}m, with intermediate strip. Double sided SVT module hosts three daisy-chained sensors on each side with a full strip length of 33 cm. There are 512 channels per module read out by four Fermilab Silicon Strip Readout (FSSR2) chips featuring data driven architecture, mounted on a rigid-flex hybrid. Modules are assembled on the barrel using unique cantilevered geometry to minimize the amount of material in the tracking volume. Design and performance of the SVT modules are presented, focusing on results of electrical measurements.

  5. System software design for the CDF Silicon Vertex Detector

    International Nuclear Information System (INIS)

    Tkaczyk, S.; Bailey, M.

    1991-11-01

    An automated system for testing and performance evaluation of the CDF Silicon Vertex Detector (SVX) data acquisition electronics is described. The SVX data acquisition chain includes the Fastbus Sequencer and the Rabbit Crate Controller and Digitizers. The Sequencer is a programmable device for which we developed a high level assembly language. Diagnostic, calibration and data acquisition programs have been developed. A distributed software package was developed in order to operate the modules. The package includes programs written in assembly and Fortran languages that are executed concurrently on the SVX Sequencer modules and either a microvax or an SSP. Test software was included to assist technical personnel during the production and maintenance of the modules. Details of the design of different components of the package are reported

  6. Displaced vertex searches for sterile neutrinos at future lepton colliders

    Energy Technology Data Exchange (ETDEWEB)

    Antusch, Stefan [Department of Physics, University of Basel, Klingelbergstr. 82, CH-4056 Basel (Switzerland); Max-Planck-Institut für Physik (Werner-Heisenberg-Institut),Föhringer Ring 6, D-80805 München (Germany); Cazzato, Eros; Fischer, Oliver [Department of Physics, University of Basel, Klingelbergstr. 82, CH-4056 Basel (Switzerland)

    2016-12-02

    We investigate the sensitivity of future lepton colliders to displaced vertices from the decays of long-lived heavy (almost sterile) neutrinos with electroweak scale masses and detectable time of flight. As future lepton colliders we consider the FCC-ee, the CEPC, and the ILC, searching at the Z-pole and at the center-of-mass energies of 240, 350 and 500 GeV. For a realistic discussion of the detector response to the displaced vertex signal and the Standard Model background we consider the ILC’s Silicon Detector (SiD) as benchmark for the future lepton collider detectors. We find that displaced vertices constitute a powerful search channel for sterile neutrinos, sensitive to squared active-sterile mixing angles as small as 10{sup −11}.

  7. The LHCb Vertex Locator (VELO) Pixel Detector Upgrade

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00536755

    2017-01-01

    The LHCb experiment is designed to perform high-precision measurements of CP violation and the decays of beauty and charm hadrons at the Large Hadron Collider (LHC) at CERN. There is a planned upgrade during Long Shutdown 2 (LS2), expected in 2019, which will allow the detector to run at higher luminosities by transforming the entire readout to a trigger-less system. This will include a substantial upgrade of the Vertex Locator (VELO), the silicon tracker that surrounds the LHCb interaction region. The VELO is moving from silicon strip technology to hybrid pixel sensors, where silicon sensors are bonded to VeloPix ASICs. Sensor prototypes have undergone rigorous testing using the Timepix3 Telescope at the SPS, CERN. The main components of the upgrade are summarised and testbeam results presented.

  8. Waterbomb base: a symmetric single-vertex bistable origami mechanism

    Science.gov (United States)

    Hanna, Brandon H.; Lund, Jason M.; Lang, Robert J.; Magleby, Spencer P.; Howell, Larry L.

    2014-09-01

    The origami waterbomb base is a single-vertex bistable origami mechanism that has unique properties which may prove useful in a variety of applications. It also shows promise as a test bed for smart materials and actuation because of its straightforward geometry and multiple phases of motion, ranging from simple to more complex. This study develops a quantitative understanding of the symmetric waterbomb base's kinetic behavior. This is done by completing kinematic and potential energy analyses to understand and predict bistable behavior. A physical prototype is constructed and tested to validate the results of the analyses. Finite element and virtual work analyses based on the prototype are used to explore the locations of the stable equilibrium positions and the force-deflection response. The model results are verified through comparisons to measurements on a physical prototype. The resulting models describe waterbomb base behavior and provide an engineering tool for application development.

  9. Topological vertex, string amplitudes and spectral functions of hyperbolic geometry

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, M.E.X.; Rosa, T.O. [Universidade Federal Fluminense, Instituto de Fisica, Av. Gal. Milton Tavares de Souza, s/n, CEP 24210-346, Niteroi, RJ (Brazil); Luna, R.M. [Universidade Estadual de Londrina, Departamento de Fisica, Caixa Postal 6001, Londrina, Parana (Brazil)

    2014-05-15

    We discuss the homological aspects of the connection between quantum string generating function and the formal power series associated to the dimensions of chains and homologies of suitable Lie algebras. Our analysis can be considered as a new straightforward application of the machinery of modular forms and spectral functions (with values in the congruence subgroup of SL(2,Z)) to the partition functions of Lagrangian branes, refined vertex and open string partition functions, represented by means of formal power series that encode Lie algebra properties. The common feature in our examples lies in the modular properties of the characters of certain representations of the pertinent affine Lie algebras and in the role of Selberg-type spectral functions of a hyperbolic three-geometry associated with q-series in the computation of the string amplitudes. (orig.)

  10. The Small Acceptance Vertex Detector of NA61/SHINE

    Science.gov (United States)

    Deveaux, M.; Aduszkiewicz, A.; Ali, Y.; Baszczyk, M.; Brylinski, W.; Dorosz, P.; Di Luise, S.; Feofilov, G.; Gazdzicki, M.; Igolkin, S.; Jablonski, M.; Kovalenko, V.; Koziel, M.; Kucewicz, W.; Larsen, D.; Lazareva, T.; Martinengo, P.; Merzlaya, A.; Mik, L.; Planeta, R.; Snoch, A.; Vechernin, V.; Tefelski, D.; Suljic, M.; Staszel, P.

    2018-02-01

    Charmonium production in heavy ion collisions is considered as an important diagnostic probe for studying the phase diagram of strongly interacting matter for potential phase transitions. The interpretation of existing data from the CERN SPS is hampered by a lack of knowledge on the properties of open charm particle production in the fireball. Moreover, open charm production in heavy ion collisions by itself is poorly understood. To overcome this obstacle, the NA61/SHINE was equipped with a Small Acceptance Vertex Detector (SAVD), which is predicted to make the experiment sensitive to open charm mesons produced in A-A collisions at the SPS top energy. This paper will introduce the concept and the hardware of the SAVD. Moreover, first running experience as obtained in a commissioning run with a 150 AGeV/c Pb+Pb collision system will be reported.

  11. Vertex measurement at a hadron collider. The ATLAS pixel detector

    International Nuclear Information System (INIS)

    Grosse-Knetter, J.

    2008-03-01

    The ATLAS Pixel Detector is the innermost layer of the ATLAS tracking system and will contribute significantly to the ATLAS track and vertex reconstruction. The detector consists of identical sensor-chip-hybrid modules, arranged in three barrels in the centre and three disks on either side for the forward region. The position of the Pixel Detector near the interaction point requires excellent radiation hardness, fast read-out, mechanical and thermal robustness, good long-term stability, all combined with a low material budget. The new design concepts used to meet the challenging requirements are discussed with their realisation in the Pixel Detector, followed by a description of a refined and extensive set of measurements to assess the detector performance during and after its construction. (orig.)

  12. Greedy Local Search and Vertex Cover in Sparse Random Graphs

    DEFF Research Database (Denmark)

    Witt, Carsten

    2009-01-01

    . This work starts with a rigorous explanation for this claim based on the refined analysis of the Karp-Sipser algorithm by Aronson et al. Subsequently, theoretical supplements are given to experimental studies of search heuristics on random graphs. For c search heuristic...... finds an optimal cover in polynomial time with a probability arbitrarily close to 1. This behavior relies on the absence of a giant component. As an additional insight into the randomized search, it is shown that the heuristic fails badly also on graphs consisting of a single tree component of maximum......Recently, various randomized search heuristics have been studied for the solution of the minimum vertex cover problem, in particular for sparse random instances according to the G(n, c/n) model, where c > 0 is a constant. Methods from statistical physics suggest that the problem is easy if c

  13. CDF silicon vertex tracker: tevatron run II preliminary results

    International Nuclear Information System (INIS)

    Ashmanskas, W.; Belforte, S.; Budagov, Yu.

    2002-01-01

    The Online Silicon Vertex Tracker (SVT) is the unique new trigger processor dedicated to the 2-D reconstruction of charged particle trajectories at Level 2 of the CDF trigger. The SVT has been successfully built, installed and operated during the 2000 and 20001 CDF data taking runs. The performance of the SVT is already very close to the design. The SVT is able to find tracks and calculate their impact parameter with high precision (σ d = 35 μm). It is possible to correct the beam position offset and give the beam position feedback to accelerator in real time. In fact, the beam position is calculated online every few seconds with an accuracy of 1 to 5 μm. The beam position is continuously sent to the accelerator control. By using trigger tracks, parent particles such as K S 's and D 0 's are reconstructed, proving that the SVT is ready to be used for physics studies

  14. vertex drift chamber construction and test results

    International Nuclear Information System (INIS)

    Clark, A.R.; Goozen, F.; Grudberg, P.; Klopfenstein, C.; Kerth, L.T.; Loken, S.C.; Oltman, E.; Strovink, M.; Trippe, T.G.

    1991-05-01

    A jet-cell based vertex chamber has been built for the D OE experiment at Fermilab and operated in a test beam there. Low drift velocity and diffusion properties were achieved using CO 2 (95%)-ethane(5%) at atmospheric pressure. The drift velocity is found to be consistent with [9.74+8.68(|E|-1.25)] μm/nsec where E is the electric field strength in (kV/cm < |E| z 1.6 kV/cm.) An intrinsic spatial resolution of 60 μm or better for drift distances greater than 2 mm is measured. The track pair efficiency is estimated to be better than 90% for separations greater than 630 μm. 8 refs., 6 figs., 1 tab

  15. CCD vertex detector for the future linear collider

    CERN Document Server

    Stefanov, K D

    2003-01-01

    The R and D program at the LCFI collaboration is dedicated to the building of CCD-based vertex detector, satisfying the challenging requirements of the proposed future linear colliders. The mechanical part of the program targets the development of precision thin detector ladders, using large back-thinned unsupported CCDs under tension. Another part of the program aims to achieve very fast readout of the sensors using column-parallel CCDs, bump bonded to a dedicated CMOS readout chip. Each column of the CCD is read and processed independently, which gives the ultimate speed performance. Some results on modelling of the proposed column parallel CCD with device simulator CAD tools are presented. Tests on fast commercial CCD are being carried out to provide information on noise performance and handling of MIP-like charges at high clock frequencies.

  16. A vertex similarity index for better personalized recommendation

    Science.gov (United States)

    Chen, Ling-Jiao; Zhang, Zi-Ke; Liu, Jin-Hu; Gao, Jian; Zhou, Tao

    2017-01-01

    Recommender systems benefit us in tackling the problem of information overload by predicting our potential choices among diverse niche objects. So far, a variety of personalized recommendation algorithms have been proposed and most of them are based on similarities, such as collaborative filtering and mass diffusion. Here, we propose a novel vertex similarity index named CosRA, which combines advantages of both the cosine index and the resource-allocation (RA) index. By applying the CosRA index to real recommender systems including MovieLens, Netflix and RYM, we show that the CosRA-based method has better performance in accuracy, diversity and novelty than some benchmark methods. Moreover, the CosRA index is free of parameters, which is a significant advantage in real applications. Further experiments show that the introduction of two turnable parameters cannot remarkably improve the overall performance of the CosRA index.

  17. Capacitively coupled hybrid pixel assemblies for the CLIC vertex detector

    CERN Document Server

    AUTHOR|(SzGeCERN)734627; Benoit, Mathieu; Dannheim, Dominik; Dette, Karola; Hynds, Daniel; Kulis, Szymon; Peric, Ivan; Petric, Marko; Redford, Sophie; Sicking, Eva; Valerio, Pierpaolo

    2016-01-01

    The vertex detector at the proposed CLIC multi-TeV linear e+e- collider must have minimal material content and high spatial resolution, combined with accurate time-stamping to cope with the expected high rate of beam-induced backgrounds. One of the options being considered is the use of active sensors implemented in a commercial high-voltage CMOS process, capacitively coupled to hybrid pixel ASICs. A prototype of such an assembly, using two custom designed chips (CCPDv3 as active sensor glued to a CLICpix readout chip), has been characterised both in the lab and in beam tests at the CERN SPS using 120 GeV/c positively charged hadrons. Results of these characterisation studies are presented both for single and dual amplification stages in the active sensor. Pixel cross-coupling results are also presented, showing the sensitivity to placement precision and planarity of the glue layer.

  18. Waterbomb base: a symmetric single-vertex bistable origami mechanism

    International Nuclear Information System (INIS)

    Hanna, Brandon H; Lund, Jason M; Magleby, Spencer P; Howell, Larry L; Lang, Robert J

    2014-01-01

    The origami waterbomb base is a single-vertex bistable origami mechanism that has unique properties which may prove useful in a variety of applications. It also shows promise as a test bed for smart materials and actuation because of its straightforward geometry and multiple phases of motion, ranging from simple to more complex. This study develops a quantitative understanding of the symmetric waterbomb base's kinetic behavior. This is done by completing kinematic and potential energy analyses to understand and predict bistable behavior. A physical prototype is constructed and tested to validate the results of the analyses. Finite element and virtual work analyses based on the prototype are used to explore the locations of the stable equilibrium positions and the force–deflection response. The model results are verified through comparisons to measurements on a physical prototype. The resulting models describe waterbomb base behavior and provide an engineering tool for application development. (paper)

  19. Nonequilibrium Statistical Operator Method and Generalized Kinetic Equations

    Science.gov (United States)

    Kuzemsky, A. L.

    2018-01-01

    We consider some principal problems of nonequilibrium statistical thermodynamics in the framework of the Zubarev nonequilibrium statistical operator approach. We present a brief comparative analysis of some approaches to describing irreversible processes based on the concept of nonequilibrium Gibbs ensembles and their applicability to describing nonequilibrium processes. We discuss the derivation of generalized kinetic equations for a system in a heat bath. We obtain and analyze a damped Schrödinger-type equation for a dynamical system in a heat bath. We study the dynamical behavior of a particle in a medium taking the dissipation effects into account. We consider the scattering problem for neutrons in a nonequilibrium medium and derive a generalized Van Hove formula. We show that the nonequilibrium statistical operator method is an effective, convenient tool for describing irreversible processes in condensed matter.

  20. Unexplored regions in QFT: an alternative resolution of the gauge-theoretic clash between localization and the Hilbert space of quantum theory

    International Nuclear Information System (INIS)

    Schroer, Bert; FU-Berlin

    2012-02-01

    Massive quantum matter of prescribed spin permits infinitely many possibilities of covariantization in terms of spinorial (undotted/dotted) pointlike fields, whereas massless nite helicity representations lead to large gap in this spinorial spectrum which for s=1 excludes vector potentials. Since the nonexistence of such pointlike generators is the result of a deep structural clash between modular localization and the Hilbert space setting of QT, there are two ways out: gauge theory which sacrifices the Hilbert space and keeps the pointlike formalism and the use of string like potentials which allows to preserve the Hilbert space. The latter setting contains also string-localized charge-carrying operators whereas the gauge theoretic formulation is limited to point-like generated observables. This description also gives a much better insight into the Higgs mechanism which leads to a revival of the more physical 'Schwinger-Higgs' screening idea. The new formalism is not limited to m=0, s=1, it leads to renormalizable inter- actions in the sense of power-counting for all s in massless representations. The existence of string like vector potentials is preempted by the Aharonov-Bohm effect in QFT; it is well-known that the use of pointlike vector potentials in Stokes theorem would with lead to wrong results. Their use in Maxwell's equations is known to lead to zero Maxwell charge. The role of string-localization in the problem behind the observed invisibility and confinement of gluons and quarks leads to new questions and problems. (author)

  1. On nonequilibrium many-body systems. 1: The nonequilibrium statistical operator method

    International Nuclear Information System (INIS)

    Algarte, A.C.S.; Vasconcellos, A.R.; Luzzi, R.; Sampaio, A.J.C.

    1985-01-01

    The theoretical aspects involved in the treatment of many-body systems strongly departed from equilibrium are discussed. The nonequilibrium statistical operator (NSO) method is considered in detail. Using Jaynes' maximum entropy formalism complemented with an ad hoc hypothesis a nonequilibrium statistical operator is obtained. This approach introduces irreversibility from the outset and we recover statistical operators like those of Green-Mori and Zubarev as particular cases. The connection with Generalized Thermodynamics and the construction of nonlinear transport equations are briefly described. (Author) [pt

  2. Nonequilibrium Phase Chemistry in High Temperature Structure Alloys

    Science.gov (United States)

    Wang, R.

    1991-01-01

    Titanium and nickel aluminides of nonequilibrium microstructures and in thin gauge thickness were identified, characterized and produced for potential high temperature applications. A high rate sputter deposition technique for rapid surveillance of the microstructures and nonequilibrium phase is demonstrated. Alloys with specific compositions were synthesized with extended solid solutions, stable dispersoids, and specific phase boundaries associated with different heat treatments. Phase stability and mechanical behavior of these nonequilibrium alloys were investigated and compared.

  3. Nonequilibrium topological phase transitions in two-dimensional optical lattices

    Science.gov (United States)

    Nakagawa, Masaya; Kawakami, Norio

    2014-01-01

    Recently, concepts of topological phases of matter are extended to nonequilibrium systems, especially periodically driven systems. In this paper, we construct an example which shows nonequilibrium topological phase transitions using ultracold fermions in optical lattices. We show that the Rabi oscillation has the possibility to induce nonequilibrium topological phases which are classified into time-reversal-invariant topological insulators for a two-orbital model of alkaline-earth-metal atoms. Furthermore, we study the nonequilibrium topological phases using time-dependent Schrieffer-Wolff-type perturbation theory, and we obtain an analytical expression to describe the topological phase transitions from a high-frequency limit of external driving fields.

  4. Quark-gluon vertex dressing and meson masses beyond ladder-rainbow truncation

    International Nuclear Information System (INIS)

    Matevosyan, Hrayr H.; Thomas, Anthony W.; Tandy, Peter C.

    2007-01-01

    We include a generalized infinite class of quark-gluon vertex dressing diagrams in a study of how dynamics beyond the ladder-rainbow truncation influences the Bethe-Salpeter description of light-quark pseudoscalar and vector mesons. The diagrammatic specification of the vertex is mapped into a corresponding specification of the Bethe-Salpeter kernel, which preserves chiral symmetry. This study adopts the algebraic format afforded by the simple interaction kernel used in previous work on this topic. The new feature of the present work is that in every diagram summed for the vertex and the corresponding Bethe-Salpeter kernel, each quark-gluon vertex is required to be the self-consistent vertex solution. We also adopt from previous work the effective accounting for the role of the explicitly non-Abelian three-gluon coupling in a global manner through one parameter determined from recent lattice-QCD data for the vertex. Within the current model, the more consistent dressed vertex limits the ladder-rainbow truncation error for vector mesons to be never more than 10% as the current quark mass is varied from the u/d region to the b region

  5. Mapping the material in the LHCb vertex locator using secondary hadronic interactions arXiv

    CERN Document Server

    Alexander, M.; Bay, A.; Bel, L.J.; van Beuzekom, M.; Bogdanova, G.; Borghi, S.; Bowcock, T.J.V.; Buchanan, E.; Buytaert, J.; Carvalho Akiba, K.; Chen, S.; Coco, V.; Collins, P.; Crocombe, A.; Da Cunha Marinho, F.; Dall'Occo, E.; De Capua, S.; Dean, C.T.; Dettori, F.; Dossett, D.; Dreimanis, K.; Dujany, G.; Eklund, L.; Evans, T.; Ferro-Luzzi, M.; Gersabeck, M.; Gershon, T.; Hadavizadeh, T.; Harrison, J.; Hennessy, K.; Hulsbergen, W.; Hutchcroft, D.; Jans, P.Ilten E.; John, M.; Kopciewicz, P.; Koppenburg, P.; Lafferty, G.; Latham, T.; Leflat, A.; Majewski, M.W.; McNulty, R.; Mylroie-Smith, J.; Oblakowska-Mucha, A.; Parkes, C.; Pearce, A.; Poluektov, A.; Pritchard, A.; Qian, W.; Redford, S.; Richards, S.; Rinnert, K.; Rodrigues, E.; Sarpis, G.; Schiller, M.; Schindler, H.; Smith, M.; Smith, N.A.; Szumlak, T.; Velthuis, J.J.; Volkov, V.; Wallace, C.; Wark, H.M.; Webber, A.; Williams, M.R.J.; Williams, M.

    Precise knowledge of the location of the material in the LHCb vertex locator (VELO) is essential to reducing background in searches for long-lived exotic particles, and in identifying jets that originate from beauty and charm quarks. Secondary interactions of hadrons produced in beam-gas collisions are used to map the location of material in the VELO. Using this material map, along with properties of a reconstructed secondary vertex and its constituent tracks, a $p$-value can be assigned to the hypothesis that the secondary vertex originates from a material interaction. A validation of this procedure is presented using photon conversions to dimuons.

  6. Wrong vertex displacements due to Lee-Wick resonances at LHC

    International Nuclear Information System (INIS)

    Alvarez, E.; Schat, C.; Rold, L. da; Szynkman, A.

    2009-01-01

    We show how a resonance from the recently proposed Lee-Wick Standard Model could lead to wrong vertex displacements at LHCb. We study which could be the possible 'longest lived' Lee-Wick particle that could be created at LHC, and we study its possible decays and detections. We conclude that there is a region in the parameter space which would give wrong vertex displacements as a unique signature of the Lee-Wick Standard Model at LHCb. Further numerical simulation shows that LHC era could explore these wrong vertex displacements through Lee-Wick leptons below 500 GeV. (author)

  7. A Vizing-like theorem for union vertex-distinguishing edge coloring

    OpenAIRE

    Bousquet, Nicolas; Dailly, Antoine; Duchene, Eric; Kheddouci, Hamamache; Parreau, Aline

    2016-01-01

    We introduce a variant of the vertex-distinguishing edge coloring problem, where each edge is assigned a subset of colors. The label of a vertex is the union of the sets of colors on edges incident to it. In this paper we investigate the problem of finding a coloring with the minimum number of colors where every pair of vertices receive distinct labels. Finding such a coloring generalizes several other well-known problems of vertex-distinguishing colorings in graphs. We show that for any grap...

  8. Matrix product algorithm for stochastic dynamics on networks applied to nonequilibrium Glauber dynamics

    Science.gov (United States)

    Barthel, Thomas; De Bacco, Caterina; Franz, Silvio

    2018-01-01

    We introduce and apply an efficient method for the precise simulation of stochastic dynamical processes on locally treelike graphs. Networks with cycles are treated in the framework of the cavity method. Such models correspond, for example, to spin-glass systems, Boolean networks, neural networks, or other technological, biological, and social networks. Building upon ideas from quantum many-body theory, our approach is based on a matrix product approximation of the so-called edge messages—conditional probabilities of vertex variable trajectories. Computation costs and accuracy can be tuned by controlling the matrix dimensions of the matrix product edge messages (MPEM) in truncations. In contrast to Monte Carlo simulations, the algorithm has a better error scaling and works for both single instances as well as the thermodynamic limit. We employ it to examine prototypical nonequilibrium Glauber dynamics in the kinetic Ising model. Because of the absence of cancellation effects, observables with small expectation values can be evaluated accurately, allowing for the study of decay processes and temporal correlations.

  9. Simple models of equilibrium and nonequilibrium phenomena

    International Nuclear Information System (INIS)

    Lebowitz, J.L.

    1987-01-01

    This volume consists of two chapters of particular interest to researchers in the field of statistical mechanics. The first chapter is based on the premise that the best way to understand the qualitative properties that characterize many-body (i.e. macroscopic) systems is to study 'a number of the more significant model systems which, at least in principle are susceptible of complete analysis'. The second chapter deals exclusively with nonequilibrium phenomena. It reviews the theory of fluctuations in open systems to which they have made important contributions. Simple but interesting model examples are emphasised

  10. Universality in Nonequilibrium Lattice Systems Theoretical Foundations

    CERN Document Server

    Ódor, Géza

    2008-01-01

    Universal scaling behavior is an attractive feature in statistical physics because a wide range of models can be classified purely in terms of their collective behavior due to a diverging correlation length. This book provides a comprehensive overview of dynamical universality classes occurring in nonequilibrium systems defined on regular lattices. The factors determining these diverse universality classes have yet to be fully understood, but the book attempts to summarize our present knowledge, taking them into account systematically.The book helps the reader to navigate in the zoo of basic m

  11. Nonequilibrium fermion production in quantum field theory

    Energy Technology Data Exchange (ETDEWEB)

    Pruschke, Jens

    2010-06-16

    The creation of matter in the early universe or in relativistic heavy-ion collisions is inevitable connected to nonequilibrium physics. One of the key challenges is the explanation of the corresponding thermalization process following nonequilibrium instabilities. The role of fermionic quantum fields in such scenarios is discussed in the literature by using approximations of field theories which neglect important quantum corrections. This thesis goes beyond such approximations. A quantum field theory where scalar bosons interact with Dirac fermions via a Yukawa coupling is analyzed in the 2PI effective action formalism. The chosen approximation allows for a correct description of the dynamics including nonequilibrium instabilities. In particular, fermion-boson loop corrections allow to study the interaction of fermions with large boson fluctuations. The applied initial conditions generate nonequilibrium instabilities like parametric resonance or spinodal instabilities. The equations of motion for correlation functions are solved numerically and major characteristics of the fermion dynamics are described by analytical solutions. New mechanisms for the production of fermions are found. Simulations in the case of spinodal instability show that unstable boson fluctuations induce exponentially growing fermion modes with approximately the same growth rate. If the unstable regime lasts long enough a thermalization of the infrared part of the fermion occupation number occurs on time scales much shorter than the time scale on which bosonic quantum fields thermalize. Fermions acquire an excess of occupation in the ultraviolet regime compared to a Fermi-Dirac statistic characterized by a power-law with exponent two. The fermion production mechanism via parametric resonance is found to be most efficient after the instability ends. Quantum corrections then provide a very efficient particle creation mechanism which is interpreted as an amplification of decay processes. The ratio

  12. Nonequilibrium dynamics in an interacting Fe-C nanoparticle system

    DEFF Research Database (Denmark)

    Jönsson, P.; Hansen, Mikkel Fougt; Nordblad, P.

    2000-01-01

    Nonequilibrium dynamics in an interacting Fe-C nanoparticle sample, exhibiting a low-temperature spin-glass-like phase, has been studied by low-frequency ac susceptibility and magnetic relaxation experiments. The nonequilibrium behavior shows characteristic spin-glass features, but some qualitative...

  13. Exploring Chemical and Thermal Non-equilibrium in Nitrogen Arcs

    International Nuclear Information System (INIS)

    Ghorui, S; Das, A K

    2012-01-01

    Plasma torches operating with nitrogen are of special importance as they can operate with usual tungsten based refractory electrodes and offer radical rich non-oxidizing high temperature environment for plasma chemistry. Strong gradients in temperature as well as species densities and huge convective fluxes lead to varying degrees of chemical non-equilibrium in associated regions. An axi-symmetric two-temperature chemical non-equilibrium model of a nitrogen plasma torch has been developed to understand the effects of thermal and chemical non-equilibrium in arcs. A 2-D finite volume CFD code in association with a non-equilibrium property routine enabled extraction of steady state self-consistent distributions of various plasma quantities inside the torch under various thermal and chemical non-equilibrium conditions. Chemical non-equilibrium has been incorporated through computation of diffusive and convective fluxes in each finite volume cell in every iteration and associating corresponding thermodynamic and transport properties through the scheme of 'chemical non-equilibrium parameter' introduced by Ghorui et. al. Recombination coefficient data from Nahar et. al. and radiation data from Krey and Morris have been used in the simulation. Results are presented for distributions of temperature, pressure, velocity, current density, electric potential, species densities and chemical non-equilibrium effects. Obtained results are compared with similar results under LTE.

  14. The quark-gluon vertex in Landau gauge bound-state studies

    International Nuclear Information System (INIS)

    Williams, Richard

    2015-01-01

    We present a practical method for the solution of the quark-gluon vertex for use in Bethe-Salpeter and Dyson-Schwinger calculations. The efficient decomposition into the necessary covariants is detailed, with the numerical algorithm outlined for both real and complex Euclidean momenta. A truncation of the quark-gluon vertex, that neglects explicit back-coupling to enable the application to bound-state calculations, is given together with results for the quark propagator and quark-gluon vertex for different quark flavours. The relative impact of the various components of the quark-gluon vertex is highlighted with the flavour dependence of the effective quark-gluon interaction obtained, thus providing insight for the construction of phenomenological models within the rainbow ladder. Finally, we solve the corresponding Green's functions for complex Euclidean momenta as required in future bound-state calculations. (orig.)

  15. Three-point vertex functions in Yang-Mills Theory and QCD in Landau gauge

    Directory of Open Access Journals (Sweden)

    Blum Adrian L.

    2017-01-01

    Full Text Available Solutions for the three-gluon and quark-gluon vertices from Dyson-Schwinger equations and the three-particle irreducible formalism are discussed. Dynamical quarks (“unquenching” change the three-gluon vertex via the quark-triangle diagrams which themselves include fully dressed quark-gluon vertex functions. On the other hand, the quark-swordfish diagram is, at least with the model used for the two-quark-two-gluon vertex employed here, of minor importance. For the leading tensor structure of the threegluon vertex the “unquenching” effect can be summarized for the nonperturbative part as a shift of the related dressing function towards the infrared.

  16. Pion production and absorption in nuclear reactions. I. The vertex function

    International Nuclear Information System (INIS)

    Nutt, W.T.; Shakin, C.M.

    1977-01-01

    We have performed a model calculation of the pion-nucleon vertex function for the case in which one nucleon is allowed to go far off its mass shell. We discuss the relevance of this vertex function for the calculation of pion production and absorption in nuclear reactions, such as (π + ,p), (p,π + ), and for the pionic disintegration of the deuteron. The model used is based upon an approximation to an exact equation for the vertex function derived from a field-theoretic model with pseudoscalar coupling. Our calculations indicate a strong dependence of the vertex function on the invariant mass of the off-shell nucleon. The results are dominated by the presence of the 1470 MeV, P 11 resonance

  17. Nonequilibrium dynamical mean-field theory

    International Nuclear Information System (INIS)

    Eckstein, Martin

    2009-01-01

    The aim of this thesis is the investigation of strongly interacting quantum many-particle systems in nonequilibrium by means of the dynamical mean-field theory (DMFT). An efficient numerical implementation of the nonequilibrium DMFT equations within the Keldysh formalism is provided, as well a discussion of several approaches to solve effective single-site problem to which lattice models such as the Hubbard-model are mapped within DMFT. DMFT is then used to study the relaxation of the thermodynamic state after a sudden increase of the interaction parameter in two different models: the Hubbard model and the Falicov-Kimball model. In the latter case an exact solution can be given, which shows that the state does not even thermalize after infinite waiting times. For a slow change of the interaction, a transition to adiabatic behavior is found. The Hubbard model, on the other hand, shows a very sensitive dependence of the relaxation on the interaction, which may be called a dynamical phase transition. Rapid thermalization only occurs at the interaction parameter which corresponds to this transition. (orig.)

  18. Nonequilibrium dynamical mean-field theory

    Energy Technology Data Exchange (ETDEWEB)

    Eckstein, Martin

    2009-12-21

    The aim of this thesis is the investigation of strongly interacting quantum many-particle systems in nonequilibrium by means of the dynamical mean-field theory (DMFT). An efficient numerical implementation of the nonequilibrium DMFT equations within the Keldysh formalism is provided, as well a discussion of several approaches to solve effective single-site problem to which lattice models such as the Hubbard-model are mapped within DMFT. DMFT is then used to study the relaxation of the thermodynamic state after a sudden increase of the interaction parameter in two different models: the Hubbard model and the Falicov-Kimball model. In the latter case an exact solution can be given, which shows that the state does not even thermalize after infinite waiting times. For a slow change of the interaction, a transition to adiabatic behavior is found. The Hubbard model, on the other hand, shows a very sensitive dependence of the relaxation on the interaction, which may be called a dynamical phase transition. Rapid thermalization only occurs at the interaction parameter which corresponds to this transition. (orig.)

  19. Nonequilibrium free diffusion in seed leachate

    Science.gov (United States)

    Ortiz G., Luis; Riquelme P., Pablo; Guzmán, R.

    2013-11-01

    In this work, we use a Schlieren-like Near Field Scattering (SNFS) setup to study nonequilibrium free diffusion behavior of a colloidal solution obtained from seeds leachate. The main objective is to compare the temporal behavior of the diffusion coefficient of seed leachate with an electric conductivity based vigor test. SNFS sizing measurements, based on Mie theory, were carried out to ensure its reliability and sensitivity. Then, we performed a typical nonequilibrium free diffusion experiment of a glycerol-water mixture. In this way, we confirmed that SNFS setup is sensitive to giant concentration fluctuations of nanocolloidal solutions. The results obtained in this stage reproduce properly the data reported elsewhere in literature. Moreover, seed leachate diffuse, in water, in a similar way that glycerol does. In both cases we used the same method (dynamic structure factor) to determine thermo-physical properties. We show that time evolution of diffusion coefficient of Lupinus Albus leachate exhibits three defined regimes as electric conductivity measurements. The results also exhibit a correspondence between the behavior of the diffusion coefficient and electric conductivity values of the two regions in the temporal range studied. Finally, we discuss biological processes involved in germination that could modulate this dependence, and the role played by the electrolytic nature of solutes.

  20. Non-equilibrium many body dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Creutz, M.; Gyulassy, M.

    1997-09-22

    This Riken BNL Research Center Symposium on Non-Equilibrium Many Body Physics was held on September 23-25, 1997 as part of the official opening ceremony of the Center at Brookhaven National Lab. A major objective of theoretical work at the center is to elaborate on the full spectrum of strong interaction physics based on QCD, including the physics of confinement and chiral symmetry breaking, the parton structure of hadrons and nuclei, and the phenomenology of ultra-relativistic nuclear collisions related to the up-coming experiments at RHIC. The opportunities and challenges of nuclear and particle physics in this area naturally involve aspects of the many body problem common to many other fields. The aim of this symposium was to find common theoretical threads in the area of non-equilibrium physics and modern transport theories. The program consisted of invited talks on a variety topics from the fields of atomic, condensed matter, plasma, astrophysics, cosmology, and chemistry, in addition to nuclear and particle physics. Separate abstracts have been indexed into the database for contributions to this workshop.

  1. Non-equilibrium many body dynamics

    International Nuclear Information System (INIS)

    Creutz, M.; Gyulassy, M.

    1997-01-01

    This Riken BNL Research Center Symposium on Non-Equilibrium Many Body Physics was held on September 23-25, 1997 as part of the official opening ceremony of the Center at Brookhaven National Lab. A major objective of theoretical work at the center is to elaborate on the full spectrum of strong interaction physics based on QCD, including the physics of confinement and chiral symmetry breaking, the parton structure of hadrons and nuclei, and the phenomenology of ultra-relativistic nuclear collisions related to the up-coming experiments at RHIC. The opportunities and challenges of nuclear and particle physics in this area naturally involve aspects of the many body problem common to many other fields. The aim of this symposium was to find common theoretical threads in the area of non-equilibrium physics and modern transport theories. The program consisted of invited talks on a variety topics from the fields of atomic, condensed matter, plasma, astrophysics, cosmology, and chemistry, in addition to nuclear and particle physics. Separate abstracts have been indexed into the database for contributions to this workshop

  2. From vertex detectors to inner trackers with CMOS pixel sensors

    CERN Document Server

    Besson, A.

    2017-01-01

    The use of CMOS Pixel Sensors (CPS) for high resolution and low material vertex detectors has been validated with the 2014 and 2015 physics runs of the STAR-PXL detector at RHIC/BNL. This opens the door to the use of CPS for inner tracking devices, with 10-100 times larger sensitive area, which require therefore a sensor design privileging power saving, response uniformity and robustness. The 350 nm CMOS technology used for the STAR-PXL sensors was considered as too poorly suited to upcoming applications like the upgraded ALICE Inner Tracking System (ITS), which requires sensors with one order of magnitude improvement on readout speed and improved radiation tolerance. This triggered the exploration of a deeper sub-micron CMOS technology, Tower-Jazz 180 nm, for the design of a CPS well adapted for the new ALICE-ITS running conditions. This paper reports the R&D results for the conception of a CPS well adapted for the ALICE-ITS.

  3. Transport coefficients of Dirac ferromagnet: Effects of vertex corrections

    Science.gov (United States)

    Fujimoto, Junji

    2018-03-01

    As a strongly spin-orbit-coupled metallic model with ferromagnetism, we have considered an extended Stoner model to the relativistic regime, named Dirac ferromagnet in three dimensions. In a previous paper [J. Fujimoto and H. Kohno, Phys. Rev. B 90, 214418 (2014), 10.1103/PhysRevB.90.214418], we studied the transport properties giving rise to the anisotropic magnetoresistance (AMR) and the anomalous Hall effect (AHE) with the impurity potential being taken into account only as the self-energy. The effects of the vertex corrections (VCs) to AMR and AHE are reported in this paper. AMR is found not to change quantitatively when the VCs are considered, although the transport lifetime is different from the one-electron lifetime and the charge current includes additional contributions from the correlation with spin currents. The side-jump and the skew-scattering contributions to AHE are also calculated. The skew-scattering contribution is dominant in the clean case as can be seen in the spin Hall effect in the nonmagnetic Dirac electron system.

  4. Error handling for the CDF Silicon Vertex Tracker

    CERN Document Server

    Belforte, S; Dell'Orso, Mauro; Donati, S; Galeotti, S; Giannetti, P; Morsani, F; Punzi, G; Ristori, L; Spinella, F; Zanetti, A M

    2000-01-01

    The SVT online tracker for the CDF upgrade reconstructs two- dimensional tracks using information from the Silicon Vertex detector (SVXII) and the Central Outer Tracker (COT). The SVT has an event rate of 100 kHz and a latency time of 10 mu s. The system is composed of 104 VME 9U digital boards (of 8 different types) and it is implemented as a data driven architecture. Each board runs on its own 30 MHz clock. Since the data output from the SVT (few Mbytes/sec) are a small fraction of the input data (200 Mbytes/sec), it is extremely difficult to track possible internal errors by using only the output stream. For this reason several diagnostic tools have been implemented: local error registers, error bits propagated through the data streams and the Spy Buffer system. Data flowing through each input and output stream of every board are continuously copied to memory banks named Spy Buffers which act as built in logic state analyzers hooked continuously to internal data streams. The contents of all buffers can be ...

  5. Error handling for the CDF online silicon vertex tracker

    CERN Document Server

    Bari, M; Cerri, A; Dell'Orso, Mauro; Donati, S; Galeotti, S; Giannetti, P; Morsani, F; Punzi, G; Ristori, L; Spinella, F; Zanetti, A M

    2001-01-01

    The online silicon vertex tracker (SVT) is composed of 104 VME 9U digital boards (of eight different types). Since the data output from the SVT (few MB/s) are a small fraction of the input data (200 MB/s), it is extremely difficult to track possible internal errors by using only the output stream. For this reason, several diagnostic tools have been implemented: local error registers, error bits propagated through the data streams, and the Spy Buffer system. Data flowing through each input and output stream of every board are continuously copied to memory banks named spy buffers, which act as built-in logic state analyzers hooked continuously to internal data streams. The contents of all buffers can be frozen at any time (e.g., on error detection) to take a snapshot of all data flowing through each SVT board. The spy buffers are coordinated at system level by the Spy Control Board. The architecture, design, and implementation of this system are described. (4 refs).

  6. Persistent magnetic vortex flow at a supergranular vertex

    Science.gov (United States)

    Requerey, Iker S.; Cobo, Basilio Ruiz; Gošić, Milan; Bellot Rubio, Luis R.

    2018-03-01

    Context. Photospheric vortex flows are thought to play a key role in the evolution of magnetic fields. Recent studies show that these swirling motions are ubiquitous in the solar surface convection and occur in a wide range of temporal and spatial scales. Their interplay with magnetic fields is poorly characterized, however. Aims: We study the relation between a persistent photospheric vortex flow and the evolution of a network magnetic element at a supergranular vertex. Methods: We used long-duration sequences of continuum intensity images acquired with Hinode and the local correlation-tracking method to derive the horizontal photospheric flows. Supergranular cells are detected as large-scale divergence structures in the flow maps. At their vertices, and cospatial with network magnetic elements, the velocity flows converge on a central point. Results: One of these converging flows is observed as a vortex during the whole 24 h time series. It consists of three consecutive vortices that appear nearly at the same location. At their core, a network magnetic element is also detected. Its evolution is strongly correlated to that of the vortices. The magnetic feature is concentrated and evacuated when it is caught by the vortices and is weakened and fragmented after the whirls disappear. Conclusions: This evolutionary behavior supports the picture presented previously, where a small flux tube becomes stable when it is surrounded by a vortex flow. A movie attached to Fig. 2 is available at http://https://www.aanda.org

  7. The silicon vertex detector of the Belle II experiment

    Science.gov (United States)

    Friedl, Markus; Bergauer, Thomas; Gfall, Immanuel; Irmler, Christian; Valentan, Manfred

    2011-02-01

    After 10 years of successful operation, the Belle experiment at KEK (Tsukuba, Japan) will be completed in 2010. Thereafter, a major upgrade of the KEK-B machine is foreseen until 2014, aiming at a final luminosity of 8×10 35 cm -2 s -1, which is about 40 times higher than the present peak value. Consequently, also the Belle experiment needs to be changed and the Silicon Vertex Detector (SVD) in particular will be completely replaced as it already operates close to its limits in the present system. The future SVD (a.k.a. SuperSVD) will consist of four layers of double-sided silicon strip detectors like the present one, but at larger radii, because it will be complemented by a two-layer pixel detector as the innermost sensing device. The SuperSVD will be entirely composed of silicon sensors made from 6 in. wafers read out by APV25 front-end chips that were originally developed for the CMS experiment at the LHC. Several years of R&D effort led to innovations such as the Origami chip-on-sensor concept and readout electronics with hit time finding which were successfully demonstrated on prototypes. These features will be included in the final system which is presently being designed. This paper will give an overview of the SuperSVD and present results from prototype tests ranging from detector modules to back-end electronics.

  8. Novel integrated CMOS pixel structures for vertex detectors

    Energy Technology Data Exchange (ETDEWEB)

    Kleinfelder, Stuart; Bieser, Fred; Chen, Yandong; Gareus, Robin; Matis, Howard S.; Oldenburg, Markus; Retiere, Fabrice; Ritter, Hans Georg; Wieman, Howard H.; Yamamoto, Eugene

    2003-10-29

    Novel CMOS active pixel structures for vertex detector applications have been designed and tested. The overriding goal of this work is to increase the signal to noise ratio of the sensors and readout circuits. A large-area native epitaxial silicon photogate was designed with the aim of increasing the charge collected per struck pixel and to reduce charge diffusion to neighboring pixels. The photogate then transfers the charge to a low capacitance readout node to maintain a high charge to voltage conversion gain. Two techniques for noise reduction are also presented. The first is a per-pixel kT/C noise reduction circuit that produces results similar to traditional correlated double sampling (CDS). It has the advantage of requiring only one read, as compared to two for CDS, and no external storage or subtraction is needed. The technique reduced input-referred temporal noise by a factor of 2.5, to 12.8 e{sup -}. Finally, a column-level active reset technique is explored that suppresses kT/C noise during pixel reset. In tests, noise was reduced by a factor of 7.6 times, to an estimated 5.1 e{sup -} input-referred noise. The technique also dramatically reduces fixed pattern (pedestal) noise, by up to a factor of 21 in our tests. The latter feature may possibly reduce pixel-by-pixel pedestal differences to levels low enough to permit sparse data scan without per-pixel offset corrections.

  9. A dynamic cellular vertex model of growing epithelial tissues

    Science.gov (United States)

    Lin, Shao-Zhen; Li, Bo; Feng, Xi-Qiao

    2017-04-01

    Intercellular interactions play a significant role in a wide range of biological functions and processes at both the cellular and tissue scales, for example, embryogenesis, organogenesis, and cancer invasion. In this paper, a dynamic cellular vertex model is presented to study the morphomechanics of a growing epithelial monolayer. The regulating role of stresses in soft tissue growth is revealed. It is found that the cells originating from the same parent cell in the monolayer can orchestrate into clustering patterns as the tissue grows. Collective cell migration exhibits a feature of spatial correlation across multiple cells. Dynamic intercellular interactions can engender a variety of distinct tissue behaviors in a social context. Uniform cell proliferation may render high and heterogeneous residual compressive stresses, while stress-regulated proliferation can effectively release the stresses, reducing the stress heterogeneity in the tissue. The results highlight the critical role of mechanical factors in the growth and morphogenesis of epithelial tissues and help understand the development and invasion of epithelial tumors.

  10. The upgrade of the LHCb Vertex Locator (VELO)

    CERN Document Server

    van Beuzekom, M

    2014-01-01

    The upgrade of the LHCb experiment, planned for 2018, will enable the detector to run at a luminosity of 2 x 10$^{33}$ cm$^{-22}$s$^{-1}$ and explore New Physics effects in the beauty and charm sector with unprecedented precision. To achieve this, the entire readout will be transformed into a triggerless system operating at 40 MHz, where the event selection algorithms will be executed by high-level software in the CPU farm. The upgraded silicon vertex detector (VELO) must be lightweight, radiation hard, vacuum compatible, and has to drive data to the data acquisition system at speeds of up to 3 Tbit/s. This challenge will be met with a new VELO design based on hybrid pixel detectors, positioned to within 5 mm of the LHC colliding beams. The sensors have 55 x 55 $\\mu$m$^2$ square pixels and the VeloPix ASIC, which is being developed for the readout, is based on the Timepix/Medipix family of chips. The hottest ASIC will have to cope with integrated hit rates of up to 900 MHz which translates to a bandwidth of m...

  11. Automatised Data Quality Monitoring of the LHCb Vertex Locator

    CERN Multimedia

    Szumlak, Tomasz

    2016-01-01

    The LHCb Vertex Locator (VELO) is a silicon strip semiconductor detector operating at just 8mm distance to the LHC beams. Its 172,000 strips are read at a frequency of 1 MHz and processed by off-detector FPGAs followed by a PC cluster that reduces the event rate to about 10 kHz. During the second run of the LHC, which lasts from 2015 until 2018, the detector performance will undergo continued change due to radiation damage effects. This necessitates a detailed monitoring of the data quality to avoid adverse effects on the physics analysis performance. The VELO monitoring infrastructure has been re-designed compared to the first run of the LHC when it was based on manual checks. The new system is based around an automatic analysis framework, which monitors the performance of new data as well as long-term trends and flags issues whenever they arise. An unbiased subset of the detector data are processed about once per hour by monitoring algorithms. The new analysis framework then analyses the plots that are prod...

  12. Jet Vertex Charge Reconstruction Poster for LHCP 2015

    CERN Document Server

    Nektarijevic, Snezana; The ATLAS collaboration

    2015-01-01

    B-jet reconstruction algorithms used so far in ATLAS data analyses do not provide the b-jet charge information, which could potentially play a major role in reducing the combinatorial backgrounds in final states with multiple b-jets. This missing point is addressed by the newly developed JetVertexCharge (JVC) algorithm presented in this poster. Inspired by the decay chain of B-hadrons, the JVC algorithm provides a multi-variate b-jet charge estimate relying on tracks, displaced vertices and muons contained in the jet. In this algorithm, the established concept of estimating jet charge as a transverse momentum weighted sum of track charges is used to reconstruct the charge of the jet as whole, as well as the charges of up to two displaced vertices in the jet, using the corresponding sets of associated tracks. The charge of the associated muon is interpreted as the same-sign or opposite-sign relative to the b-jet charge, according to its transverse momentum and geometrical match to vertices. Jets are divided in...

  13. A vertex trigger based on cylindrical multiwire proportional chambers

    Energy Technology Data Exchange (ETDEWEB)

    Becker, J.; Boesiger, K.; Lindfeld, L.; Mueller, K.; Robmann, P.; Schmitt, S.; Schmitz, C.; Steiner, S. [Physik-Institut, Universitaet Zuerich, CH-8057 Zurich (Switzerland); Straumann, U. [Physik-Institut, Universitaet Zuerich, CH-8057 Zurich (Switzerland)], E-mail: strauman@physik.unizh.ch; Szeker, K.; Truoel, P.; Urban, M.; Vollhardt, A.; Werner, N. [Physik-Institut, Universitaet Zuerich, CH-8057 Zurich (Switzerland); Baumeister, D.; Loechner, S. [ASIC-Laboratory, Kirchhoff-Institut fuer Physik, D-69120 Heidelberg (Germany); Hildebrandt, M. [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland)

    2008-02-21

    This article describes the technical implementation and the performance of the z-vertex trigger (CIP2k), which is part of the H1-experiment at HERA. The HERA storage ring and collider was designed to investigate electron (and positron) proton scattering at a center-of-mass energy of 320 GeV. To improve the sensitivity for detecting non-standard model physics and other high momentum transfer phenomena, the HERA ring has been ungraded between 2000 and 2003 to increase the specific luminosity for the experiments. In order to cope with the increased event and background rate the experiments were upgraded, too. The CIP2k trigger system is based on a set of five cylindrical multiwire proportional chambers with cathode pad readout, and allows to distinguish between events induced by beam background and ep-interactions at the first trigger stage. The trigger decision is calculated dead-time free with a latency of 1.5{mu}s in parallel to the beam clock at 10.4 MHz. The trigger-logic is realized in large field programmable gate arrays (FPGA) using the hardware description language Verilog. The system is operational since October 2003. It suppresses background events with high efficiency and provides event timing information, as designed.

  14. The silicon vertex detector of the Belle II experiment

    Energy Technology Data Exchange (ETDEWEB)

    Friedl, Markus, E-mail: friedl@hephy.a [Institute of High Energy Physics, Nikolsdorfergasse 18, A-1050 Vienna (Austria); Bergauer, Thomas; Gfall, Immanuel; Irmler, Christian; Valentan, Manfred [Institute of High Energy Physics, Nikolsdorfergasse 18, A-1050 Vienna (Austria)

    2011-02-01

    After 10 years of successful operation, the Belle experiment at KEK (Tsukuba, Japan) will be completed in 2010. Thereafter, a major upgrade of the KEK-B machine is foreseen until 2014, aiming at a final luminosity of 8x10{sup 35} cm{sup -2} s{sup -1}, which is about 40 times higher than the present peak value. Consequently, also the Belle experiment needs to be changed and the Silicon Vertex Detector (SVD) in particular will be completely replaced as it already operates close to its limits in the present system. The future SVD (a.k.a. SuperSVD) will consist of four layers of double-sided silicon strip detectors like the present one, but at larger radii, because it will be complemented by a two-layer pixel detector as the innermost sensing device. The SuperSVD will be entirely composed of silicon sensors made from 6 in. wafers read out by APV25 front-end chips that were originally developed for the CMS experiment at the LHC. Several years of R and D effort led to innovations such as the Origami chip-on-sensor concept and readout electronics with hit time finding which were successfully demonstrated on prototypes. These features will be included in the final system which is presently being designed. This paper will give an overview of the SuperSVD and present results from prototype tests ranging from detector modules to back-end electronics.

  15. The silicon vertex detector of the Belle II experiment

    International Nuclear Information System (INIS)

    Friedl, Markus; Bergauer, Thomas; Gfall, Immanuel; Irmler, Christian; Valentan, Manfred

    2011-01-01

    After 10 years of successful operation, the Belle experiment at KEK (Tsukuba, Japan) will be completed in 2010. Thereafter, a major upgrade of the KEK-B machine is foreseen until 2014, aiming at a final luminosity of 8x10 35 cm -2 s -1 , which is about 40 times higher than the present peak value. Consequently, also the Belle experiment needs to be changed and the Silicon Vertex Detector (SVD) in particular will be completely replaced as it already operates close to its limits in the present system. The future SVD (a.k.a. SuperSVD) will consist of four layers of double-sided silicon strip detectors like the present one, but at larger radii, because it will be complemented by a two-layer pixel detector as the innermost sensing device. The SuperSVD will be entirely composed of silicon sensors made from 6 in. wafers read out by APV25 front-end chips that were originally developed for the CMS experiment at the LHC. Several years of R and D effort led to innovations such as the Origami chip-on-sensor concept and readout electronics with hit time finding which were successfully demonstrated on prototypes. These features will be included in the final system which is presently being designed. This paper will give an overview of the SuperSVD and present results from prototype tests ranging from detector modules to back-end electronics.

  16. Susceptibility and vertex corrections for a square Fermi surface

    International Nuclear Information System (INIS)

    Djajaputra, D.; Ruvalds, J.

    1999-01-01

    The authors investigate the response of an electron system which exhibits ideal nesting features. Using the standard Matsubara formalism they derive analytic expressions for the imaginary and real parts of the bare particle-hole susceptibility. The imaginary part has sharp peaks whose maxima at the nesting momenta approximately scale with (ω/T). The peak lineshapes resemble neutron scattering data on chromium and some copper oxide superconductors. The real part of the bare susceptibility at the nestling vectors diverges logarithmically at low temperatures. Analytic formulae for the first vertex correction to the susceptibility are derived for a Hubbard interaction and its momentum and temperature variations are calculated numerically. This term detracts substantially from the ordinary RPA terms for intermediate values of the Coulomb repulsion. Exact cancellation of a certain class of diagrams at half filling is shown to result from particle-hole symmetry. They discuss the consequences of these results for spin fluctuation theories of high temperature superconductors and spin density wave instabilities

  17. Twist Field as Three String Interaction Vertex in Light Cone String Field Theory

    OpenAIRE

    Kishimoto, Isao; Moriyama, Sanefumi; Teraguchi, Shunsuke

    2006-01-01

    It has been suggested that matrix string theory and light-cone string field theory are closely related. In this paper, we investigate the relation between the twist field, which represents string interactions in matrix string theory, and the three-string interaction vertex in light-cone string field theory carefully. We find that the three-string interaction vertex can reproduce some of the most important OPEs satisfied by the twist field.

  18. On trees with total domination number equal to edge-vertex ...

    Indian Academy of Sciences (India)

    We say that a support vertex is strong (weak, respectively) if it is adjacent to at least two leaves (exactly one leaf, respectively). The edge incident with a leaf is called an end edge. We denote by Pn the path on n vertices. Let T be a tree, and let v be a vertex of T . We say that v is adjacent to a path Pn if there is a neighbor of v, ...

  19. Neutrino interaction vertex location with the help of electronic detectors in the OPERA experiment

    International Nuclear Information System (INIS)

    Gornushkin, Yu.A.; Dmitrievskij, S.G.; Chukanov, A.V.

    2015-01-01

    OPERA experiment is designed for the direct observation of ν τ appearance from ν μ →ν τ oscillation in a ν μ beam. Description of the procedure of neutrino interaction vertex localization (Brick Finding) by the electronic detectors of a hybrid OPERA setup is presented. The procedure includes muon track and hadronic shower axis reconstruction and determination of the target bricks with the highest probability to contain the vertex.

  20. Pion-nucleon vertex function with an off-shell nucleon

    International Nuclear Information System (INIS)

    Nutt, W.T.; Shakin, C.M.

    1977-01-01

    A model calculation for the π-N vertex function is presented in the case in which there is a single off-mass-shell nucleon and a (nearly) on-mass-shell pion. Very strong effects due to the P 11 resonance at 1470 MeV are found. A simple parametrization of the vertex function is prvided in the case that at least one nucleon is on its mass shell. (Auth.)

  1. Studies of the Triple PomeronVertex in perturbative QCD and its applications in phenomenology

    Energy Technology Data Exchange (ETDEWEB)

    Kutak, K.

    2006-12-15

    We study the properties of the Triple Pomeron Vertex in the perturbative QCD using the twist expansion method. Such analysis allows us to find the momenta configurations preferred by the vertex. When the momentum transfer is zero, the dominant contribution in the limit when N{sub c}{yields}{infinity} comes from anticollinear pole. This is in agreement with result obtained without expanding, but by direct averaging of the Triple Pomeron Vertex over angles. Resulting theta functions show that the anticollinear configuration is optimal for the vertex. In the finite N{sub c} case the collinear term also contributes. Using the Triple Pomeron Vertex we construct a pomeron loop and we also consider four gluon propagation between two Triple Pomeron Vertices. We apply the Triple Pomeron Vertex to construct the Hamiltonian from which we derive the Balitsky-Kovchegov equation for an unintegrated gluon density. In order to apply this equation to phenomenology, we apply the Kwiecinski-Martin-Stasto model for higher order corrections to a linear part of the Balitsky-Kovchegov equation. We introduce the definition of the saturation scale which reflects properties of this equation. Finally, we use it for computation of observables, such as the F{sub 2} structure function and diffractive Higgs boson production cross section. The impact of screening corrections on F{sub 2} is negligible, but those effects turn out to be significant for diffractive Higgs boson production at LHC.

  2. TECHNICAL DESIGN REPORT OF THE FORWARD SILICON VERTEX (FVTX)

    Energy Technology Data Exchange (ETDEWEB)

    PHENIX EXPERIMENT; OBRIEN,E.; PAK, R.; DREES, K.A.; (PHENIX EXPERIMENT COLLABORATORS)

    2007-08-01

    The main goal of the RHIC heavy ion program is the discovery of the novel ultra-hot high-density state of matter predicted by the fundamental theory of strong interactions and created in collisions of heavy nuclei, the Quark-Gluon Plasma (QGP). From measurements of the large elliptic flow of light mesons and baryons and their large suppression at high transverse momentum pT that have been made at RHIC, there is evidence that new degrees of freedom, characteristic of a deconfined QCD medium, drive the dynamics of nucleus-nucleus collisions. It has been recognized, however, that the potential of light quarks and gluons to characterize the properties of the QGP medium is limited and the next phase of the RHIC program calls for the precise determination of its density, temperature, opacity and viscosity using qualitatively new probes, such as heavy quarks. We propose the construction of two Forward Silicon Vertex Trackers (FVTX) for the PHENIX experiment that will directly identify and distinguish charm and beauty decays within the acceptance of the muon spectrometers. The FVTX will provide this essential coverage over a range of forward and backward rapidities (1.2 < |y| < 2.4)--a rapidity range coverage which not only brings significantly larger acceptance to PHENIX but which is critical for separating cold nuclear matter effects from QGP effects and is critical for measuring the proton spin contributions over a significant fraction of the kinematic range of interest. In addition, the FVTX will provide greatly reduced background and improved mass resolution for dimuon events, culminating in the first measurements of the {upsilon}{prime} and Drell-Yan at RHIC. These same heavy flavor and dimuon measurements in p+p collisions will allow us to place significant constraints on the gluon and sea quark contributions to the proton's spin and to make fundamentally new tests of the Sivers function universality.

  3. TECHNICAL DESIGN REPORT OF THE FORWARD SILICON VERTEX (FVTX)

    International Nuclear Information System (INIS)

    PHENIX EXPERIMENT; OBRIEN, E.; PAK, R.; DREES, K.A.

    2007-01-01

    The main goal of the RHIC heavy ion program is the discovery of the novel ultra-hot high-density state of matter predicted by the fundamental theory of strong interactions and created in collisions of heavy nuclei, the Quark-Gluon Plasma (QGP). From measurements of the large elliptic flow of light mesons and baryons and their large suppression at high transverse momentum pT that have been made at RHIC, there is evidence that new degrees of freedom, characteristic of a deconfined QCD medium, drive the dynamics of nucleus-nucleus collisions. It has been recognized, however, that the potential of light quarks and gluons to characterize the properties of the QGP medium is limited and the next phase of the RHIC program calls for the precise determination of its density, temperature, opacity and viscosity using qualitatively new probes, such as heavy quarks. We propose the construction of two Forward Silicon Vertex Trackers (FVTX) for the PHENIX experiment that will directly identify and distinguish charm and beauty decays within the acceptance of the muon spectrometers. The FVTX will provide this essential coverage over a range of forward and backward rapidities (1.2 < |y| < 2.4)--a rapidity range coverage which not only brings significantly larger acceptance to PHENIX but which is critical for separating cold nuclear matter effects from QGP effects and is critical for measuring the proton spin contributions over a significant fraction of the kinematic range of interest. In addition, the FVTX will provide greatly reduced background and improved mass resolution for dimuon events, culminating in the first measurements of the υ(prime) and Drell-Yan at RHIC. These same heavy flavor and dimuon measurements in p+p collisions will allow us to place significant constraints on the gluon and sea quark contributions to the proton's spin and to make fundamentally new tests of the Sivers function universality

  4. Non-equilibrium synergistic effects in atmospheric pressure plasmas.

    Science.gov (United States)

    Guo, Heng; Zhang, Xiao-Ning; Chen, Jian; Li, He-Ping; Ostrikov, Kostya Ken

    2018-03-19

    Non-equilibrium is one of the important features of an atmospheric gas discharge plasma. It involves complicated physical-chemical processes and plays a key role in various actual plasma processing. In this report, a novel complete non-equilibrium model is developed to reveal the non-equilibrium synergistic effects for the atmospheric-pressure low-temperature plasmas (AP-LTPs). It combines a thermal-chemical non-equilibrium fluid model for the quasi-neutral plasma region and a simplified sheath model for the electrode sheath region. The free-burning argon arc is selected as a model system because both the electrical-thermal-chemical equilibrium and non-equilibrium regions are involved simultaneously in this arc plasma system. The modeling results indicate for the first time that it is the strong and synergistic interactions among the mass, momentum and energy transfer processes that determine the self-consistent non-equilibrium characteristics of the AP-LTPs. An energy transfer process related to the non-uniform spatial distributions of the electron-to-heavy-particle temperature ratio has also been discovered for the first time. It has a significant influence for self-consistently predicting the transition region between the "hot" and "cold" equilibrium regions of an AP-LTP system. The modeling results would provide an instructive guidance for predicting and possibly controlling the non-equilibrium particle-energy transportation process in various AP-LTPs in future.

  5. Nontrivial nonequilibrium critical relaxation in cluster algorithms and universal nonequilibrium-to-equilibrium scaling procedure

    Science.gov (United States)

    Nonomura, Yoshihiko; Tomita, Yusuke

    2015-03-01

    Recently we have found that the nonequilibrium relaxation from the perfectly-ordered state of the 2D and 3D Ising models in cluster algorithms shows nontrivial stretched-exponential decay at the transition temperature. Similar nontrivial nonequilibrium critical relaxation is also observed in the 2D XY, 3D XY and 3D Heisenberg models; simple exponential decay in these cases. In order to confirm these behaviors and evaluate the scaling form precisely and robustly, we have proposed a universal scaling procedure to connect nonequilibrium and equilibrium behaviors continuously. For example, when the critical relaxation of the average magnetization of a system with linear size L is observed in local-update algorithms, this quantity decays in a power law in the early-stage relaxation with ~t - β / (zν) and converges to the critical magnetization mc (L) ~L - β / ν in equilibrium. Then, when L β / ν is plotted versus tL-z , data for various system sizes are scaled on a single curve in the whole parameter region. This procedure also holds for the cases with cluster algorithms.

  6. Thermodynamics of Nonequilibrium Systems with Feedback Control

    Science.gov (United States)

    Sagawa, Takahiro

    2015-03-01

    In modern nonequilibrium physics, ``Maxwell's demon'' has attracted renewed attentions in both terms of theory and experiment. The demon plays a key role to unify thermodynamics and information theory, which can extract the useful work from a heat bath by using the obtained information via feedback control. In this talk, I will talk about the recent development of thermodynamics of information. In particular, I will focus on the generalizations of the second law of thermodynamics and the Jarzynski equality in the presence of feedback control, where information contents and thermodynamic quantities are treated on an equal footing. I will also discuss recent experimental results that realized Maxwell's demon by colloidal particles and single electrons.

  7. Non-equilibrium in flowing atmospheric plasmas

    International Nuclear Information System (INIS)

    Haas, J.C.M. de.

    1986-01-01

    This thesis deals with the fundamental aspects of two different plasmas applied in technological processes. The first one is the cesium seeded argon plasma in a closed cycle Magnetohydrodynamic (MHD) generator, the second is the thermal argon plasma in a cascade arc with an imposed flow. In Chapter 2 the influence of non-equilibrium on the mass and energy balances of a plasma is worked out. The general theory presented there can be applied to both the plasma in an MHD generator and to the cascade arc with imposed flow. Introductions to these plasmas are given in the Chapters 3 and 6 respectively. These chapters are both followed by two chapters which treat the theoretical and the experimental investigations. The results are summarized in Chapter 9. (Auth.)

  8. Non-equilibrium effects in the plasmas

    International Nuclear Information System (INIS)

    Einfeld, D.

    1975-01-01

    Radial dependences of non-equilibrium effects of a He plasma were studied in a wall-stabilized short-time discharge. The electron density (nsub(e) = 2.5 x 10 22 m -3 ), the electron temperature and the equilibrium shift were determined by calculations of the continuum beam density and the beam densities of one He-I and one He-II line, respectively. In the discharge axis, the overpopulation factors of the ground state of He-I and He-II are about 75. As the distance to the axis increases, they increase for He-I and decrease for He-II. Except for the usual errors of measurement, the overpopulation factors found here correspond to those calculated from the balance equations (Drawin). (orig./AK) [de

  9. Nonequilibrium work relation in a macroscopic system

    International Nuclear Information System (INIS)

    Sughiyama, Yuki; Ohzeki, Masayuki

    2013-01-01

    We reconsider a well-known relationship between the fluctuation theorem and the second law of thermodynamics by evaluating stochastic evolution of the density field (probability measure valued process). In order to establish a bridge between microscopic and macroscopic behaviors, we must take the thermodynamic limit of a stochastic dynamical system following the standard procedure in statistical mechanics. The thermodynamic path characterizing a dynamical behavior in the macroscopic scale can be formulated as an infimum of the action functional for the stochastic evolution of the density field. In our formulation, the second law of thermodynamics can be derived only by symmetry of the action functional without recourse to the Jarzynski equality. Our formulation leads to a nontrivial nonequilibrium work relation for metastable (quasi-stationary) states, which are peculiar in the macroscopic system. We propose a prescription for computing the free energy for metastable states based on the resultant work relation. (paper)

  10. Magnetic polarons in a nonequilibrium polariton condensate

    Science.gov (United States)

    Mietki, Paweł; Matuszewski, Michał

    2017-09-01

    We consider a condensate of exciton polaritons in a diluted magnetic semiconductor microcavity. Such a system may exhibit magnetic self-trapping in the case of sufficiently strong coupling between polaritons and magnetic ions embedded in the semiconductor. We investigate the effect of the nonequilibrium nature of exciton polaritons on the physics of the resulting self-trapped magnetic polarons. We find that multiple polarons can exist at the same time, and we derive a critical condition for self-trapping that is different from the one predicted previously in the equilibrium case. Using the Bogoliubov-de Gennes approximation, we calculate the excitation spectrum and provide a physical explanation in terms of the effective magnetic attraction between polaritons, mediated by the ion subsystem.

  11. Shortcuts to isothermality and nonequilibrium work relations.

    Science.gov (United States)

    Li, Geng; Quan, H T; Tu, Z C

    2017-07-01

    In conventional thermodynamics, it is widely acknowledged that the realization of an isothermal process for a system requires a quasistatic controlling protocol. Here we propose and design a strategy to realize a finite-rate isothermal transition from an equilibrium state to another one at the same temperature, which is named the "shortcut to isothermality." By using shortcuts to isothermality, we derive three nonequilibrium work relations, including an identity between the free-energy difference and the mean work due to the potential of the original system, a Jarzynski-like equality, and the inverse relationship between the dissipated work and the total driving time. We numerically test these three relations by considering the motion of a Brownian particle trapped in a harmonic potential and dragged by a time-dependent force.

  12. Nanoscale hotspots due to nonequilibrium thermal transport

    International Nuclear Information System (INIS)

    Sinha, Sanjiv; Goodson, Kenneth E.

    2004-01-01

    Recent experimental and modeling efforts have been directed towards the issue of temperature localization and hotspot formation in the vicinity of nanoscale heat generating devices. The nonequilibrium transport conditions which develop around these nanoscale devices results in elevated temperatures near the heat source which can not be predicted by continuum diffusion theory. Efforts to determine the severity of this temperature localization phenomena in silicon devices near and above room temperature are of technological importance to the development of microelectronics and other nanotechnologies. In this work, we have developed a new modeling tool in order to explore the magnitude of the additional thermal resistance which forms around nanoscale hotspots from temperatures of 100-1000K. The models are based on a two fluid approximation in which thermal energy is transferred between ''stationary'' optical phonons and fast propagating acoustic phonon modes. The results of the model have shown excellent agreement with experimental results of localized hotspots in silicon at lower temperatures. The model predicts that the effect of added thermal resistance due to the nonequilibrium phonon distribution is greatest at lower temperatures, but is maintained out to temperatures of 1000K. The resistance predicted by the numerical code can be easily integrated with continuum models in order to predict the temperature distribution around nanoscale heat sources with improved accuracy. Additional research efforts also focused on the measurements of the thermal resistance of silicon thin films at higher temperatures, with a focus on polycrystalline silicon. This work was intended to provide much needed experimental data on the thermal transport properties for micro and nanoscale devices built with this material. Initial experiments have shown that the exposure of polycrystalline silicon to high temperatures may induce recrystallization and radically increase the thermal

  13. Vertex Stimulation as a Control Site for Transcranial Magnetic Stimulation: A Concurrent TMS/fMRI Study

    OpenAIRE

    Jung, JeYoung; Bungert, Andreas; Bowtell, Richard; Jackson, Stephen R.

    2016-01-01

    Background A common control condition for transcranial magnetic stimulation (TMS) studies is to apply stimulation at the vertex. An assumption of vertex stimulation is that it has relatively little influence over on-going brain processes involved in most experimental tasks, however there has been little attempt to measure neural changes linked to vertex TMS. Here we directly test this assumption by using a concurrent TMS/fMRI paradigm in which we investigate fMRI blood-oxygenation-level-depen...

  14. Law of large numbers for the SIR model with random vertex weights on Erdős-Rényi graph

    Science.gov (United States)

    Xue, Xiaofeng

    2017-11-01

    In this paper we are concerned with the SIR model with random vertex weights on Erdős-Rényi graph G(n , p) . The Erdős-Rényi graph G(n , p) is generated from the complete graph Cn with n vertices through independently deleting each edge with probability (1 - p) . We assign i. i. d. copies of a positive r. v. ρ on each vertex as the vertex weights. For the SIR model, each vertex is in one of the three states 'susceptible', 'infective' and 'removed'. An infective vertex infects a given susceptible neighbor at rate proportional to the production of the weights of these two vertices. An infective vertex becomes removed at a constant rate. A removed vertex will never be infected again. We assume that at t = 0 there is no removed vertex and the number of infective vertices follows a Bernoulli distribution B(n , θ) . Our main result is a law of large numbers of the model. We give two deterministic functions HS(ψt) ,HV(ψt) for t ≥ 0 and show that for any t ≥ 0, HS(ψt) is the limit proportion of susceptible vertices and HV(ψt) is the limit of the mean capability of an infective vertex to infect a given susceptible neighbor at moment t as n grows to infinity.

  15. The MAPS based PXL vertex detector for the STAR experiment

    International Nuclear Information System (INIS)

    Contin, G.; Anderssen, E.; Greiner, L.; Silber, J.; Stezelberger, T.; Vu, C.; Wieman, H.; Woodmansee, S.; Schambach, J.; Sun, X.; Szelezniak, M.

    2015-01-01

    The Heavy Flavor Tracker (HFT) was installed in the STAR experiment for the 2014 heavy ion run of RHIC. Designed to improve the vertex resolution and extend the measurement capabilities in the heavy flavor domain, the HFT is composed of three different silicon detectors based on CMOS monolithic active pixels (MAPS), pads and strips respectively, arranged in four concentric cylinders close to the STAR interaction point. The two innermost HFT layers are placed at a radius of 2.7 and 8 cm from the beam line, respectively, and accommodate 400 ultra-thin (50 μ m) high resolution MAPS sensors arranged in 10-sensor ladders to cover a total silicon area of 0.16 m 2 . Each sensor includes a pixel array of 928 rows and 960 columns with a 20.7 μ m pixel pitch, providing a sensitive area of ∼ 3.8 cm 2 . The architecture is based on a column parallel readout with amplification and correlated double sampling inside each pixel. Each column is terminated with a high precision discriminator, is read out in a rolling shutter mode and the output is processed through an integrated zero suppression logic. The results are stored in two SRAM with ping-pong arrangement for a continuous readout. The sensor features 185.6 μ s readout time and 170 mW/cm 2 power dissipation. The detector is air-cooled, allowing a global material budget as low as 0.39% on the inner layer. A novel mechanical approach to detector insertion enables effective installation and integration of the pixel layers within an 8 hour shift during the on-going STAR run.In addition to a detailed description of the detector characteristics, the experience of the first months of data taking will be presented in this paper, with a particular focus on sensor threshold calibration, latch-up protection procedures and general system operations aimed at stabilizing the running conditions. Issues faced during the 2014 run will be discussed together with the implemented solutions. A preliminary analysis of the detector

  16. Detecting the solution space of vertex cover by mutual determinations and backbones.

    Science.gov (United States)

    Wei, Wei; Zhang, Renquan; Guo, Binghui; Zheng, Zhiming

    2012-07-01

    To solve the combinatorial optimization problems, especially the minimal Vertex-cover problem with high efficiency, is a significant task in theoretical computer science and many other subjects. Aiming at detecting the solution space of Vertex-cover, a new structure named mutual-determination is defined and discovered for Vertex-cover on general graphs, which results in the emergence of strong correlations among the unfrozen nodes. Based on the backbones and mutual-determinations with node ranks by leaf removal, we propose a Mutual-determination and Backbone Evolution Algorithm to achieve the reduced solution graph, which provides a graphical expression of the solution space of Vertex-cover. By this algorithm, the whole solution space and detailed structures such as backbones can be obtained strictly when there is no leaf-removal core on the given graph. Compared with the current algorithms, the Mutual-determination and Backbone Evolution Algorithm performs as well as the replica symmetry one in a certain interval but has a small gap higher than the replica symmetric breaking one and has a relatively small error for the exact results. The algorithm with the mutual-determination provides a new viewpoint to solve Vertex-cover and understand the organizations of the solution spaces, and the reduced solution graph gives an alternative way to catch detailed information of the ground/steady states.

  17. Vertex finding performance studies for the Phase II CMS Level-1 Trigger

    CERN Document Server

    Udrescu, Silviu Marian

    2017-01-01

    At the HL-LHC, a significant increase in the luminosity delivered to CMS will result in a pileup per bunch crossing of 140-200. This provides a difficult environment to obtain reliable physics results and keep trigger rates manageable. In order to mitigate this problem, tracker information will be used, for the first time, at the Level-1 (L1) trigger. This will allow the primary vertex reconstruction at L1. In this report, an investigation into the vertex finding performance of a potential algorithm is presented. The vertex finding efficiency was measured as a function of several variables, such as the percentage of tracks associated to the primary vertex within the barrel and the pT of the tracks. The efficiency was found to not depend significantly on the pileup for the samples analyzed, however, a strong dependence was observed on the number of tracks associated with the primary vertex.

  18. Nonequilibrium electron transport through quantum dots in the Kondo regime

    DEFF Research Database (Denmark)

    Wölfle, Peter; Paaske, Jens; Rosch, Achim

    2005-01-01

    Electron transport at large bias voltage through quantum dots in the Kondo regime is described within the perturbative renormalization group extended to nonequilibrium. The conductance, local magnetization, dynamical spin susceptibility and local spectral function are calculated. We show how the ...

  19. Non-Equilibrium Thermodynamics of Self-Replicating Protocells

    DEFF Research Database (Denmark)

    Fellermann, Harold; Corominas-Murtra, Bernat; Hansen, Per Lyngs

    2018-01-01

    We provide a non-equilibrium thermodynamic description of the life-cycle of a droplet based, chemically feasible, system of protocells. By coupling the protocells metabolic kinetics with its thermodynamics, we demonstrate how the system can be driven out of equilibrium to ensure protocell growth...... and replication. This coupling allows us to derive the equations of evolution and to rigorously demonstrate how growth and replication life-cycle can be understood as a non-equilibrium thermodynamic cycle. The process does not appeal to genetic information or inheritance, and is based only on non......-equilibrium physics considerations. Our non-equilibrium thermodynamic description of simple, yet realistic, processes of protocell growth and replication, represents an advance in our physical understanding of a central biological phenomenon both in connection to the origin of life and for modern biology....

  20. Nonequilibrium structure of colloidal dumbbells under oscillatory shear.

    Science.gov (United States)

    Heptner, Nils; Chu, Fangfang; Lu, Yan; Lindner, Peter; Ballauff, Matthias; Dzubiella, Joachim

    2015-11-01

    We investigate the nonequilibrium behavior of dense, plastic-crystalline suspensions of mildly anisotropic colloidal hard dumbbells under the action of an oscillatory shear field by employing Brownian dynamics computer simulations. In particular, we extend previous investigations, where we uncovered nonequilibrium phase transitions, to other aspect ratios and to a larger nonequilibrium parameter space, that is, a wider range of strains and shear frequencies. We compare and discuss selected results in the context of scattering and rheological experiments. Both simulations and experiments demonstrate that the previously found transitions from the plastic crystal phase with increasing shear strain also occur at other aspect ratios. We explore the transition behavior in the strain-frequency phase and summarize it in a nonequilibrium phase diagram. Additionally, the experimental rheology results hint at a slowing down of the colloidal dynamics with higher aspect ratio.

  1. Electrolytes: transport properties and non-equilibrium thermodynamics

    International Nuclear Information System (INIS)

    Miller, D.G.

    1980-12-01

    This paper presents a review on the application of non-equilibrium thermodynamics to transport in electrolyte solutions, and some recent experimental work and results for mutual diffusion in electrolyte solutions

  2. Nonequilibrium phonon effects in midinfrared quantum cascade lasers

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Y. B., E-mail: yshi9@wisc.edu; Knezevic, I., E-mail: knezevic@engr.wisc.edu [Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706-1691 (United States)

    2014-09-28

    We investigate the effects of nonequilibrium phonon dynamics on the operation of a GaAs-based midinfrared quantum cascade laser over a range of temperatures (77–300 K) via a coupled ensemble Monte Carlo simulation of electron and optical-phonon systems. Nonequilibrium phonon effects are shown to be important below 200 K. At low temperatures, nonequilibrium phonons enhance injection selectivity and efficiency by drastically increasing the rate of interstage electron scattering from the lowest injector state to the next-stage upper lasing level via optical-phonon absorption. As a result, the current density and modal gain at a given field are higher and the threshold current density lower and considerably closer to experiment than results obtained with thermal phonons. By amplifying phonon absorption, nonequilibrium phonons also hinder electron energy relaxation and lead to elevated electronic temperatures.

  3. Nonequilibrium flow calculations for the hydrogen constricted arc

    Science.gov (United States)

    Scott, R. K.; Incropera, F. P.

    1973-01-01

    A nonequilibrium flow model has been formulated and solved numerically for conditions in an atomic hydrogen cascade arc. Solutions show that although thermal nonequilibrium effects are minor, the departure from chemical equilibrium is significant. Comparisons with results obtained from an equilibrium flow model reveal the deficiencies associated with such a model and parametric calculations reveal the effect of current, pressure, and radius on arc behavior.

  4. Non-equilibrium dynamics from RPMD and CMD.

    Science.gov (United States)

    Welsch, Ralph; Song, Kai; Shi, Qiang; Althorpe, Stuart C; Miller, Thomas F

    2016-11-28

    We investigate the calculation of approximate non-equilibrium quantum time correlation functions (TCFs) using two popular path-integral-based molecular dynamics methods, ring-polymer molecular dynamics (RPMD) and centroid molecular dynamics (CMD). It is shown that for the cases of a sudden vertical excitation and an initial momentum impulse, both RPMD and CMD yield non-equilibrium TCFs for linear operators that are exact for high temperatures, in the t = 0 limit, and for harmonic potentials; the subset of these conditions that are preserved for non-equilibrium TCFs of non-linear operators is also discussed. Furthermore, it is shown that for these non-equilibrium initial conditions, both methods retain the connection to Matsubara dynamics that has previously been established for equilibrium initial conditions. Comparison of non-equilibrium TCFs from RPMD and CMD to Matsubara dynamics at short times reveals the orders in time to which the methods agree. Specifically, for the position-autocorrelation function associated with sudden vertical excitation, RPMD and CMD agree with Matsubara dynamics up to O(t 4 ) and O(t 1 ), respectively; for the position-autocorrelation function associated with an initial momentum impulse, RPMD and CMD agree with Matsubara dynamics up to O(t 5 ) and O(t 2 ), respectively. Numerical tests using model potentials for a wide range of non-equilibrium initial conditions show that RPMD and CMD yield non-equilibrium TCFs with an accuracy that is comparable to that for equilibrium TCFs. RPMD is also used to investigate excited-state proton transfer in a system-bath model, and it is compared to numerically exact calculations performed using a recently developed version of the Liouville space hierarchical equation of motion approach; again, similar accuracy is observed for non-equilibrium and equilibrium initial conditions.

  5. Mode coupling theory for nonequilibrium glassy dynamics of thermal self-propelled particles.

    Science.gov (United States)

    Feng, Mengkai; Hou, Zhonghuai

    2017-06-28

    We present a mode coupling theory study for the relaxation and glassy dynamics of a system of strongly interacting self-propelled particles, wherein the self-propulsion force is described by Ornstein-Uhlenbeck colored noise and thermal noises are included. Our starting point is an effective Smoluchowski equation governing the distribution function of particle positions, from which we derive a memory function equation for the time dependence of density fluctuations in nonequilibrium steady states. With the basic assumption of the absence of macroscopic currents and standard mode coupling approximation, we can obtain expressions for the irreducible memory function and other relevant dynamic terms, wherein the nonequilibrium character of the active system is manifested through an averaged diffusion coefficient D[combining macron] and a nontrivial structural function S 2 (q) with q being the magnitude of wave vector q. D[combining macron] and S 2 (q) enter the frequency term and the vertex term for the memory function, and thus influence both the short time and the long time dynamics of the system. With these equations obtained, we study the glassy dynamics of this thermal self-propelled particle system by investigating the Debye-Waller factor f q and relaxation time τ α as functions of the persistence time τ p of self-propulsion, the single particle effective temperature T eff as well as the number density ρ. Consequently, we find the critical density ρ c for given τ p shifts to larger values with increasing magnitude of propulsion force or effective temperature, in good accordance with previously reported simulation work. In addition, the theory facilitates us to study the critical effective temperature T for fixed ρ as well as its dependence on τ p . We find that T increases with τ p and in the limit τ p → 0, it approaches the value for a simple passive Brownian system as expected. Our theory also well recovers the results for passive systems and can be

  6. Achieving Radiation Tolerance through Non-Equilibrium Grain Boundary Structures.

    Science.gov (United States)

    Vetterick, Gregory A; Gruber, Jacob; Suri, Pranav K; Baldwin, Jon K; Kirk, Marquis A; Baldo, Pete; Wang, Yong Q; Misra, Amit; Tucker, Garritt J; Taheri, Mitra L

    2017-09-25

    Many methods used to produce nanocrystalline (NC) materials leave behind non-equilibrium grain boundaries (GBs) containing excess free volume and higher energy than their equilibrium counterparts with identical 5 degrees of freedom. Since non-equilibrium GBs have increased amounts of both strain and free volume, these boundaries may act as more efficient sinks for the excess interstitials and vacancies produced in a material under irradiation as compared to equilibrium GBs. The relative sink strengths of equilibrium and non-equilibrium GBs were explored by comparing the behavior of annealed (equilibrium) and as-deposited (non-equilibrium) NC iron films on irradiation. These results were coupled with atomistic simulations to better reveal the underlying processes occurring on timescales too short to capture using in situ TEM. After irradiation, NC iron with non-equilibrium GBs contains both a smaller number density of defect clusters and a smaller average defect cluster size. Simulations showed that excess free volume contribute to a decreased survival rate of point defects in cascades occurring adjacent to the GB and that these boundaries undergo less dramatic changes in structure upon irradiation. These results suggest that non-equilibrium GBs act as more efficient sinks for defects and could be utilized to create more radiation tolerant materials in future.

  7. Nonequilibrium emergent phenomena in organic molecular solids

    Energy Technology Data Exchange (ETDEWEB)

    Mitrano, Matteo

    2015-07-15

    The manipulation of matter with ultrashort laser pulses is a relevant research field from both a fundamental and an applied perspective, owing to the efficient coupling to the electronic degrees of freedom on femtosecond timescales and the ability to induce transient phases that cannot be realized in equilibrium scenarios. Strongly correlated materials are a natural environment for the observation of such novel and emergent out-of-equilibrium physics because small modifications to the electron-electron interactions can induce transitions between remarkably different macroscopic phases. One of the most effective means of modifying the effective electron-electron interactions is to perturb the crystal structure through pressure, strain or even light. However, it remains largely unexplored how perturbing the structural degrees of freedom affects the electron dynamics of the transiently driven states and how the interplay of correlations and electron-lattice interactions determine the intrinsic timescales of these nonequilibrium states. This thesis investigates how to control the light-induced nonequilibrium electronic properties in strongly correlated organics, that are highly tunable with moderate variations of external parameters, by perturbing their structural degrees of freedom, either via static pressures or vibrational excitation. We study the role of correlations in determining the relaxation rate of holes (holons) and double occupancies (doublons) in a solid state Mott insulator, the ET-F{sub 2}TCNQ, driven across a transient insulator-to-metal transition. By mapping holon-doublon lifetimes onto the ground-state electronic interactions, we found that the decay rate of the photoinjected quasiparticles depends on the degree of correlation between carriers and is affected by the presence of a competition between local recombination and delocalization of holon-doublon pairs. By optically controlling the effective correlations in organic molecular crystals through

  8. Complex Dynamics in Nonequilibrium Economics and Chemistry

    Science.gov (United States)

    Wen, Kehong

    Complex dynamics provides a new approach in dealing with economic complexity. We study interactively the empirical and theoretical aspects of business cycles. The way of exploring complexity is similar to that in the study of an oscillatory chemical system (BZ system)--a model for modeling complex behavior. We contribute in simulating qualitatively the complex periodic patterns observed from the controlled BZ experiments to narrow the gap between modeling and experiment. The gap between theory and reality is much wider in economics, which involves studies of human expectations and decisions, the essential difference from natural sciences. Our empirical and theoretical studies make substantial progress in closing this gap. With the help from the new development in nonequilibrium physics, i.e., the complex spectral theory, we advance our technique in detecting characteristic time scales from empirical economic data. We obtain correlation resonances, which give oscillating modes with decays for correlation decomposition, from different time series including S&P 500, M2, crude oil spot prices, and GNP. The time scales found are strikingly compatible with business experiences and other studies in business cycles. They reveal the non-Markovian nature of coherent markets. The resonances enhance the evidence of economic chaos obtained by using other tests. The evolving multi-humped distributions produced by the moving-time -window technique reveal the nonequilibrium nature of economic behavior. They reproduce the American economic history of booms and busts. The studies seem to provide a way out of the debate on chaos versus noise and unify the cyclical and stochastic approaches in explaining business fluctuations. Based on these findings and new expectation formulation, we construct a business cycle model which gives qualitatively compatible patterns to those found empirically. The soft-bouncing oscillator model provides a better alternative than the harmonic oscillator

  9. Measurement of the charm and beauty structure functions using the H1 vertex detector at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Bucharest Univ. (Romania). Faculty of Physics; Aldaya Martin, M. [DESY, Hamburg (Germany); Alexa, C. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (RO)] (and others)

    2009-06-15

    Inclusive charm and beauty cross sections are measured in e{sup -}p and e{sup +}p neutral current collisions at HERA in the kinematic region of photon virtuality 5{<=}Q{sup 2}{<=}2000 GeV{sup 2} and Bjorken scaling variable 0.0002{<=}x{<=}0.05. The data were collected with the H1 detector in the years 2006 and 2007 corresponding to an integrated luminosity of 189 pb{sup -1}. The numbers of charm and beauty events are determined using variables reconstructed by the H1 vertex detector including the impact parameter of tracks to the primary vertex and the position of the secondary vertex. The measurements are combined with previous data and compared to QCD predictions. (orig.)

  10. ATLAS strategy for primary vertex reconstruction during Run-2 of the LHC

    CERN Document Server

    Borissov, Guennadi; The ATLAS collaboration; Grimm, Kathryn; Pagan Griso, Simone; Pedersen, Lars Egholm; Prokofiev, Kirill; Rudolph, Matthew Scott; Wharton, Andrew Mark

    2015-01-01

    The reconstruction of vertices corresponding to proton--proton collisions in ATLAS is an essential element of event reconstruction used in many performance studies and physics analyses. During Run-1 of the LHC, ATLAS has employed an iterative approach to vertex finding. In order to improve the flexibility of the algorithm and ensure continued performance for very high numbers of simultaneous collisions in Run-2 of the LHC and beyond, a new approach to seeding vertex finding has been developed inspired by image reconstruction techniques. This note provides a brief outline of how reconstructed tracks are used to create an image of likely vertex collisions in an event, describes the implementation in the ATLAS software, and presents some preliminary results of the performance of the algorithm in simulation approximating early Run-2 conditions.

  11. Modeling & Informatics at Vertex Pharmaceuticals Incorporated: our philosophy for sustained impact.

    Science.gov (United States)

    McGaughey, Georgia; Patrick Walters, W

    2017-03-01

    Molecular modelers and informaticians have the unique opportunity to integrate cross-functional data using a myriad of tools, methods and visuals to generate information. Using their drug discovery expertise, information is transformed to knowledge that impacts drug discovery. These insights are often times formulated locally and then applied more broadly, which influence the discovery of new medicines. This is particularly true in an organization where the members are exposed to projects throughout an organization, such as in the case of the global Modeling & Informatics group at Vertex Pharmaceuticals. From its inception, Vertex has been a leader in the development and use of computational methods for drug discovery. In this paper, we describe the Modeling & Informatics group at Vertex and the underlying philosophy, which has driven this team to sustain impact on the discovery of first-in-class transformative medicines.

  12. Application of laser differential confocal technique in back vertex power measurement for phoropters

    Science.gov (United States)

    Li, Fei; Li, Lin; Ding, Xiang; Liu, Wenli

    2012-10-01

    A phoropter is one of the most popular ophthalmic instruments used in optometry and the back vertex power (BVP) is one of the most important parameters to evaluate the refraction characteristics of a phoropter. In this paper, a new laser differential confocal vertex-power measurement method which takes advantage of outstanding focusing ability of laser differential confocal (LDC) system is proposed for measuring the BVP of phoropters. A vertex power measurement system is built up. Experimental results are presented and some influence factor is analyzed. It is demonstrated that the method based on LDC technique has higher measurement precision and stronger environmental anti-interference capability compared to existing methods. Theoretical analysis and experimental results indicate that the measurement error of the method is about 0.02m-1.

  13. Measurement of the Charm and Beauty Structure Functions using the H1 Vertex Detector at HERA

    CERN Document Server

    Aaron, FD; Alexa, C; Alimujiang, K; Andreev, V; Antunovic, B; Asmone, A; Backovic, S; Baghdasaryan, A; Barrelet, E; Bartel, W; Begzsuren, K; Belousov, A; Bizot, J C; Boudry, V; Bozovic-Jelisavcic, I; Bracinik, J; Brandt, G; Brinkmann, M; Brisson, V; Bruncko, D; Bunyatyan, A; Buschhorn, G; Bystritskaya, L; Campbell, A J; Cantun Avila, K B; Cassol-Brunner, F; Cerny, K; Cerny, V; Chekelian, V; Cholewa, A; Contreras, J G; Coughlan, J A; Cozzika, G; Cvach, J; Dainton, J B; Daum, K; Deak, M; de Boer, Y; Delcourt, B; Del Degan, M; Delvax, J; De Wolf, E A; Diaconu, C; Dodonov, V; Dossanov, A; Dubak, A; Eckerlin, G; Efremenko, V; Egli, S; Eliseev, A; Elsen, E; Falkiewicz, A; Favart, L; Fedotov, A; Felst, R; Feltesse, J; Ferencei, J; Fischer, D -J; Fleischer, M; Fomenko, A; Gabathuler, E; Gayler, J; Ghazaryan, Samvel; Glazov, A; Glushkov, I; Goerlich, L; Gogitidze, N; Gouzevitch, M; Grab, C; Greenshaw, T; Grell, B R; Grindhammer, G; Habib, S; Haidt, D; Helebrant, C; Henderson, R C W; Hennekemper, E; Henschel, H; Herbst, M; Herrera, G; Hildebrandt, M; Hiller, K H; Hoffmann, D; Horisberger, R; Hreus, T; Jacquet, M; Janssen, M E; Janssen, X; Jonsson, L; Jung, Andreas Werner; Jung, H; Kapichine, M; Katzy, J; Kenyon, I R; Kiesling, C; Klein, M; Kleinwort, C; Kluge, T; Knutsson, A; Kogler, R; Kostka, P; Kraemer, M; Krastev, K; Kretzschmar, J; Kropivnitskaya, A; Kruger, K; Kutak, K; Landon, M P J; Lange, W; Lastovicka-Medin, G; Laycock, P; Lebedev, A; Leibenguth, G; Lendermann, V; Levonian, S; Li, G; Lipka, K; Liptaj, A; List, B; List, J; Loktionova, N; Lopez-Fernandez, R; Lubimov, V; Lytkin, L; Makankine, A; Malinovski, E; Marage, P; Marti, Ll; Martyn, H -U; Maxfield, S J; Mehta, A; Meyer, A B; Meyer, H; Meyer, H; Meyer, J; Michels, V; Mikocki, S; Milcewicz-Mika, I; Moreau, F; Morozov, A; Morris, J V; Mozer, Matthias Ulrich; Mudrinic, M; Muller, K; Murin, P; Naumann, Th; Newman, P R; Niebuhr, C; Nikiforov, A; Nowak, G; Nowak, K; Nozicka, M; Olivier, B; Olsson, J E; Osman, S; Ozerov, D; Palichik, V; Panagoulias, I; Pandurovic, M; Papadopoulou, Th; Pascaud, C; Patel, G D; Pejchal, O; Perez, E; Petrukhin, A; Picuric, I; Piec, S; Pitzl, D; Placakyte, R; Pokorny, B; Polifka, R; Povh, B; Preda, T; Radescu, V; Rahmat, A J; Raicevic, N; Raspiareza, A; Ravdandorj, T; Reimer, P; Rizvi, E; Robmann, P; Roland, B; Roosen, R; Rostovtsev, A; Rotaru, M; Ruiz Tabasco, J E; Rurikova, Z; Rusakov, S; Salek, D; Sankey, D P C; Sauter, M; Sauvan, E; Schmitt, S; Schoeffel, L; Schoning, A; Schultz-Coulon, H -C; Sefkow, F; Shaw-West, R N; Shtarkov, L N; Shushkevich, S; Sloan, T; Smiljanic, Ivan; Soloviev, Y; Sopicki, P; South, D; Spaskov, V; Specka, Arnd E; Staykova, Z; Steder, M; Stella, B; Stoicea, G; Straumann, U; Sunar, D; Sykora, T; Tchoulakov, V; Thompson, G; Thompson, P D; Toll, T; Tomasz, F; Tran, T H; Traynor, D; Trinh, T N; Truol, P; Tsakov, I; Tseepeldorj, B; Turnau, J; Urban, K; Valkarova, A; Vallee, C; Van Mechelen, P; Vargas Trevino, A; Vazdik, Y; Vinokurova, S; Volchinski, V; von den Driesch, M; Wegener, D; Wissing, Ch; Wunsch, E; Zacek, J; Zalesak, J; Zhang, Z; Zhokin, A; Zimmermann, T; Zohrabyan, H; Zomer, F; Zus, R

    2010-01-01

    Inclusive charm and beauty cross sections are measured in e-p and e+p neutral current collisions at HERA in the kinematic region of photon virtuality 5vertex detector including the impact parameter of tracks to the primary vertex and the position of the secondary vertex. The measurements are combined with previous data and compared to QCD predictions.

  14. A Dyson-Schwinger study of the four-gluon vertex

    Science.gov (United States)

    Cyrol, Anton K.; Huber, Markus Q.; Smekal, Lorenz von

    2015-03-01

    We present a self-consistent calculation of the four-gluon vertex of Landau gauge Yang-Mills theory from a truncated Dyson-Schwinger equation. The equation contains the leading diagrams in the ultraviolet and is solved using as the only input results for lower Green functions from previous Dyson-Schwinger calculations that are in good agreement with lattice data. All quantities are therefore fixed and no higher Green functions enter within this truncation. Our self-consistent solution resolves the full momentum dependence of the vertex but is limited to the tree-level tensor structure at the moment. Calculations of selected dressing functions for other tensor structures from this solution are used to exemplify that they are suppressed compared to the tree-level structure except for possible logarithmic enhancements in the deep infrared. Our results furthermore allow one to extract a qualitative fit for the vertex and a running coupling.

  15. On the transfer matrix of the supersymmetric eight-vertex model. I. Periodic boundary conditions

    Science.gov (United States)

    Hagendorf, Christian; Liénardy, Jean

    2018-03-01

    The square-lattice eight-vertex model with vertex weights a, b, c, d obeying the relation (a^2+ab)(b^2+ab) = (c^2+ab)(d^2+ab) and periodic boundary conditions is considered. It is shown that the transfer matrix of the model for L  =  2n  +  1 vertical lines and periodic boundary conditions along the horizontal direction possesses the doubly degenerate eigenvalue \\Thetan = (a+b){\\hspace{0pt}}2n+1 . This proves a conjecture by Stroganov from 2001. The proof uses the supersymmetry of a related XYZ spin-chain Hamiltonian. The eigenstates of the transfer matrix corresponding to \\Thetan are shown to be the ground states of the spin-chain Hamiltonian. Moreover, for positive vertex weights \\Thetan is the largest eigenvalue of the transfer matrix.

  16. A new efficient RLF-like algorithm for the vertex coloring problem

    Directory of Open Access Journals (Sweden)

    Adegbindin Mourchid

    2016-01-01

    Full Text Available The Recursive Largest First (RLF algorithm is one of the most popular greedy heuristics for the vertex coloring problem. It sequentially builds color classes on the basis of greedy choices. In particular, the first vertex placed in a color class C is one with a maximum number of uncolored neighbors, and the next vertices placed in C are chosen so that they have as many uncolored neighbors which cannot be placed in C. These greedy choices can have a significant impact on the performance of the algorithm, which explains why we propose alternative selection rules. Computational experiments on 63 difficult DIMACS instances show that the resulting new RLF-like algorithm, when compared with the standard RLF, allows to obtain a reduction of more than 50% of the gap between the number of colors used and the best known upper bound on the chromatic number. The new greedy algorithm even competes with basic metaheuristics for the vertex coloring problem.

  17. Study of the vertex trigger performance on test-beam data

    CERN Document Server

    Teubert, F

    1999-01-01

    99-030 The performance of the Level-1 vertex trigger algorithm on test-beam data collected with a prototype of the VDET detector is presented. The effect of the detectors misalignment on the Level-1 vertex trigger performance is shown to be a critical issue if the relative position is not controlled better than $100~\\mu$m. The Primary vertex resolution on the longitudinal direction obtained on the test-beam for 2D-tracks ($270~\\mu$m), translates into a resolution close to $80~\\mu$m for the statistics of an LHC event in good agreement with expectations. The discriminating power between B-events and Minimum Bias events is studied using a sample of ``artificial'' events built from events interacting at different targets separated by 1~cm. The results are very encouraging showing the feasibility to trigger on low multiplicity displaced vertices.

  18. Measurement of the charm and beauty structure functions using the H1 vertex detector at HERA

    International Nuclear Information System (INIS)

    Aaron, F.D.; Alexa, C.; Preda, T.; Rotaru, M.; Stoicea, G.; Zus, R.; Aldaya Martin, M.; Alimujiang, K.; Antunovic, B.; Bartel, W.; Brandt, G.; Campbell, A.J.; Cholewa, A.; Deak, M.; Boer, Y. de; Eckerlin, G.; Elsen, E.; Felst, R.; Fischer, D.J.; Fleischer, M.; Gayler, J.; Glazov, A.; Gouzevitch, M.; Grell, B.R.; Haidt, D.; Helebrant, C.; Janssen, M.E.; Jung, H.; Katzy, J.; Kleinwort, C.; Knutsson, A.; Kraemer, M.; Krastev, K.; Kutak, K.; Levonian, S.; Lipka, K.; List, J.; Marti, L.; Meyer, A.B.; Meyer, H.; Meyer, J.; Michels, V.; Niebuhr, C.; Nikiforov, A.; Nozicka, M.; Olsson, J.E.; Panagoulias, I.; Papadopoulou, T.; Pitzl, D.; Placakyte, R.; Radescu, V.; Rurikova, Z.; Schmitt, S.; Schoeffel, L.; Sefkow, F.; Staykova, Z.; Steder, M.; Vargas Trevino, A.; Vinokurova, S.; Driesch, M. von den; Wissing, C.; Wuensch, E.; Andreev, V.; Belousov, A.; Eliseev, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Loktionova, N.; Malinovski, E.; Rusakov, S.; Shtarkov, L.N.; Soloviev, Y.; Vazdik, Y.; Asmone, A.; Stella, B.; Backovic, S.; Dubak, A.; Lastovicka-Medin, G.; Picuric, I.; Raicevic, N.; Baghdasaryan, A.; Ghazaryan, S.; Volchinski, V.; Zohrabyan, H.; Barrelet, E.; Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B.; Bizot, J.C.; Brisson, V.; Delcourt, B.; Jacquet, M.; Li, G.; Pascaud, C.; Tran, T.H.; Zhang, Z.; Zomer, F.; Boudry, V.; Moreau, F.; Specka, A.; Bozovic-Jelisavcic, I.; Mudrinic, M.; Pandurovic, M.; Smiljanic, I.; Bracinik, J.; Kenyon, I.R.; Newman, P.R.; Shaw-West, R.N.; Thompson, P.D.; Brinkmann, M.; Habib, S.; List, B.; Pokorny, B.; Toll, T.; Bruncko, D.; Cerny, V.; Ferencei, J.; Murin, P.; Tomasz, F.; Bunyatyan, A.; Buschhorn, G.; Chekelian, V.; Dossanov, A.; Grindhammer, G.; Kiesling, C.; Kogler, R.; Liptaj, A.; Olivier, B.; Raspiareza, A.; Shushkevich, S.; Bystritskaya, L.; Efremenko, V.; Fedotov, A.; Kropivnitskaya, A.; Lubimov, V.; Ozerov, D.; Petrukhin, A.; Rostovtsev, A.; Zhokin, A.; Cantun Avila, K.B.; Contreras, J.G.; Ruiz Tabasco, J.E.; Cassol-Brunner, F.; Diaconu, C.; Hoffmann, D.; Sauvan, E.; Trinh, T.N.; Vallee, C.; Cerny, K.; Pejchal, O.; Polifka, R.; Salek, D.; Valkarova, A.; Zacek, J.; Coughlan, J.A.; Morris, J.V.; Sankey, D.P.C.; Cozzika, G.; Feltesse, J.; Perez, E.; Cvach, J.; Reimer, P.; Zalesak, J.; Dainton, J.B.; Gabathuler, E.; Greenshaw, T.; Klein, M.; Kluge, T.; Kretzschmar, J.; Laycock, P.; Maxfield, S.J.; Mehta, A.; Patel, G.D.; Rahmat, A.J.; Daum, K.; Meyer, H.; Del Degan, M.; Grab, C.; Leibenguth, G.; Sauter, M.; Zimmermann, T.; Delvax, J.; Wolf, E.A. de; Favart, L.; Hreus, T.; Janssen, X.; Marage, P.; Mozer, M.U.; Roland, B.; Roosen, R.; Sunar, D.; Sykora, T.; Mechelen, P. van; Dodonov, V.; Lytkin, L.; Povh, B.; Egli, S.; Hildebrandt, M.; Horisberger, R.; Falkiewicz, A.; Goerlich, L.; Mikocki, S.; Milcewicz-Mika, I.; Nowak, G.; Sopicki, P.; Turnau, J.; Glushkov, I.; Henschel, H.; Hiller, K.H.; Kostka, P.; Lange, W.; Naumann, T.; Piec, S.; Henderson, R.C.W.; Sloan, T.; Hennekemper, E.; Herbst, M.; Jung, A.W.; Krueger, K.; Lendermann, V.; Schultz-Coulon, H.C.; Urban, K.; Herrera, G.; Lopez-Fernandez, R.; Joensson, L.; Osman, S.; Kapichine, M.; Makankine, A.; Morozov, A.; Palichik, V.; Spaskov, V.; Tchoulakov, V.; Landon, M.P.J.; Rizvi, E.; Thompson, G.; Traynor, D.; Martyn, H.U.; Mueller, K.; Nowak, K.; Robmann, P.; Straumann, U.; Truoel, P.; Schoening, A.; South, D.; Wegener, D.; Tsakov, I.

    2010-01-01

    Inclusive charm and beauty cross sections are measured in e - p and e + p neutral current collisions at HERA in the kinematic region of photon virtuality 5≤Q 2 ≤2000 GeV 2 and Bjorken scaling variable 0.0002≤x≤0.05. The data were collected with the H1 detector in the years 2006 and 2007 corresponding to an integrated luminosity of 189 pb -1 . The numbers of charm and beauty events are determined using variables reconstructed by the H1 vertex detector including the impact parameter of tracks to the primary vertex and the position of the secondary vertex. The measurements are combined with previous data and compared to QCD predictions. (orig.)

  19. Nonseparable frequency dependence of the two-particle vertex in interacting fermion systems

    Science.gov (United States)

    Vilardi, Demetrio; Taranto, Ciro; Metzner, Walter

    2017-12-01

    We derive functional flow equations for the two-particle vertex and the self-energy in interacting fermion systems which capture the full frequency dependence of both quantities. The equations are applied to the hole-doped two-dimensional Hubbard model as a prototype system with entangled magnetic, charge, and pairing fluctuations. Each fluctuation channel acquires substantial dependencies on all three Matsubara frequencies, such that the frequency dependence of the vertex cannot be accurately represented by a channel sum with only one frequency variable in each term. At the temperatures we are able to access, the leading instabilities are mostly antiferromagnetic, with an incommensurate wave vector. However, at large doping, a divergence in the charge channel occurs at a finite frequency transfer, if the vertex flow is computed without self-energy feedback. This enigmatic instability was already observed in a calculation by Husemann et al. [C. Husemann, K.-U. Giering, and M. Salmhofer, Phys. Rev. B 85, 075121 (2012), 10.1103/PhysRevB.85.075121], who used an approximate separable ansatz for the frequency dependence of the vertex. We identify a simple mechanism for this instability in terms of a random-phase approximation for the charge channel with a frequency dependent effective magnetic interaction as input. In spite of the strong momentum and frequency dependence of the vertex, the self-energy has a Fermi-liquid form. At the moderate interaction strength where our approach is applicable, we obtain a moderate reduction of the quasiparticle weight and a sizable decay rate with a pronounced momentum dependence. Nevertheless, the self-energy feedback into the vertex flow turns out to be crucial, as it suppresses the unphysical finite frequency charge instability.

  20. Nonequilibrium landscape theory of neural networks

    Science.gov (United States)

    Yan, Han; Zhao, Lei; Hu, Liang; Wang, Xidi; Wang, Erkang; Wang, Jin

    2013-01-01

    The brain map project aims to map out the neuron connections of the human brain. Even with all of the wirings mapped out, the global and physical understandings of the function and behavior are still challenging. Hopfield quantified the learning and memory process of symmetrically connected neural networks globally through equilibrium energy. The energy basins of attractions represent memories, and the memory retrieval dynamics is determined by the energy gradient. However, the realistic neural networks are asymmetrically connected, and oscillations cannot emerge from symmetric neural networks. Here, we developed a nonequilibrium landscape–flux theory for realistic asymmetrically connected neural networks. We uncovered the underlying potential landscape and the associated Lyapunov function for quantifying the global stability and function. We found the dynamics and oscillations in human brains responsible for cognitive processes and physiological rhythm regulations are determined not only by the landscape gradient but also by the flux. We found that the flux is closely related to the degrees of the asymmetric connections in neural networks and is the origin of the neural oscillations. The neural oscillation landscape shows a closed-ring attractor topology. The landscape gradient attracts the network down to the ring. The flux is responsible for coherent oscillations on the ring. We suggest the flux may provide the driving force for associations among memories. We applied our theory to rapid-eye movement sleep cycle. We identified the key regulation factors for function through global sensitivity analysis of landscape topography against wirings, which are in good agreements with experiments. PMID:24145451

  1. Nonequilibrium in a low power arcjet nozzle

    Science.gov (United States)

    Zube, Dieter M.; Myers, Roger M.

    1991-01-01

    Emission spectroscopy measurements were made of the plasma flow inside the nozzle of a 1 kW class arcjet thruster. The thruster propellant was a hydrogen-nitrogen mixture used to simulate fully decomposed hydrazine. The 0.25 mm diameter holes were drilled into the diverging section of the tungsten thruster nozzle to provide optical access to the internal flow. Atomic electron excitation, vibrational, and rotational temperatures were determined for the expanding plasma using relative line intensity techniques. The atomic excitation temperatures decreased from 18,000K at a location 3 mm downstream of the constrictor to 9,000K at a location 9 mm from the constrictor, while the molecular vibrational and rotational temperatures decreased from 6,500K to 2,500K and from 8,000K to 3,000K, respectively, between the same locations. The electron density measured using hydrogen H line Stark broadening decreased from about 10(exp 15) cm(-3) to about 2 times 10(exp 14) cm(-3) during the expansion. The results show that the plasma is highly nonequilibrium throughout the nozzle, with most relaxation times equal or exceeding the particle residence time.

  2. Gibbsian Stationary Non-equilibrium States

    Science.gov (United States)

    De Carlo, Leonardo; Gabrielli, Davide

    2017-09-01

    We study the structure of stationary non-equilibrium states for interacting particle systems from a microscopic viewpoint. In particular we discuss two different discrete geometric constructions. We apply both of them to determine non reversible transition rates corresponding to a fixed invariant measure. The first one uses the equivalence of this problem with the construction of divergence free flows on the transition graph. Since divergence free flows are characterized by cyclic decompositions we can generate families of models from elementary cycles on the configuration space. The second construction is a functional discrete Hodge decomposition for translational covariant discrete vector fields. According to this, for example, the instantaneous current of any interacting particle system on a finite torus can be canonically decomposed in a gradient part, a circulation term and an harmonic component. All the three components are associated with functions on the configuration space. This decomposition is unique and constructive. The stationary condition can be interpreted as an orthogonality condition with respect to an harmonic discrete vector field and we use this decomposition to construct models having a fixed invariant measure.

  3. The SuperB Silicon Vertex Tracker and 3D vertical integration

    CERN Document Server

    Re, Valerio

    2011-01-01

    The construction of the SuperB high luminosity collider was approved and funded by the Italian government in 2011. The performance specifications set by the target luminosity of this machine (> 10^36 cm^-2 s^-1) ask for the development of a Silicon Vertex Tracker with high resolution, high tolerance to radiation and excellent capability of handling high data rates. This paper reviews the R&D activity that is being carried out for the SuperB SVT. Special emphasis is given to the option of exploiting 3D vertical integration to build advanced pixel sensors and readout electronics that are able to comply with SuperB vertexing requirements.

  4. Vertex operators for the closed bosonic string theory at arbitrary genus in the operator formalism

    International Nuclear Information System (INIS)

    Lugo, A.R.

    1990-01-01

    A systematic procedure for constructing vertex operators for the physical states of the closed bosonic string theory at genus g in the operator formalism is presented. The method is based on imposing suitable commutation relations with the generators of the conformal transformations required by unitarity of scattering amplitudes. An Arakelov-type metric on the Riemann surface naturally arises in the case of the tachyon, which allows to define vertex operators at higher levels via covariant derivatives. They involve covariant derivatives of the curvature with respect to this metric as it happens in the path integral approach. As a particular result, the Fradkin-Tseytlin dilaton coupling is obtained

  5. Development of new assembly techniques for a silicon micro-vertex detector unit using the flip-chip bonding method

    International Nuclear Information System (INIS)

    Saitoh, Y.; Takeuchi, H.; Mandai, M.; Kanazawa, H.; Yamanaka, J.; Miyahara, S.; Kamiya, M.; Fujita, Y.; Higashi, Y.; Ikeda, H.; Ikeda, M.; Koike, S.; Matsuda, T.; Ozaki, H.; Tanaka, M.; Tsuboyama, T.; Avrillon, S.; Okuno, S.; Haba, J.; Hanai, H.; Mori, S.; Yusa, K.; Fukunaga, C.

    1994-01-01

    Full-size models of a detector unit for a silicon micro-vertex detector were built for the KEK B factory. The Flip-Chip Bonding (FCB) method using a new type anisotropic conductive film was examined. The structure using the FCB method successfully provides a new architecture for the silicon micro-vertex detector unit. (orig.)

  6. Experimental studies in non-equilibrium physics

    Science.gov (United States)

    Cressman, John Robert, Jr.

    This work is a collection of three experiments aimed at studying different facets of non-equilibrium dynamics. Chapter I concerns strongly compressible turbulence, which turns out to be very different from incompressible turbulence. The focus is on the dispersion of contaminants in such a flow. This type of turbulence can be studied, at very low mach number, by measuring the velocity fields of particles that float on a turbulently stirred body of water. It turns out that in the absence of incompressibility, the turbulence causes particles to cluster rather than to disperse. The implications of the observations are far reaching and include the transport of pollutants on the oceans surface, phytoplankton growth, as well as industrial applications. Chapter II deals with the effects of polymer additives on drag reduction and turbulent suppression, a well-known phenomenon that is not yet understood. In an attempt to simplify the problem, the effects of a polymer additive were investigated in a vortex street formed in a flowing soap film. Measurements suggest that an increase in elongational viscosity is responsible for a substantial reduction in periodic velocity fluctuations. This study also helps to illuminate the mechanism responsible for vortex separation in the wake of a bluff body. Chapter III describes an experiment designed to test a theoretical approach aimed at generalizing the classical fluctuation dissipation theorem (FDT). This theorem applies to systems driven only slightly away from thermal equilibrium, whereas ours, a liquid crystal under-going electroconvection, is so strongly driven, that the FDT does not apply. Both theory and experiment focus on the flux in global power fluctuations. Physical limitations did not permit a direct test of the theory, however it was possible to establish several interesting characteristics of the system: the source of the fluctuations is the transient defect structures that are generated when the system is driven hard

  7. Vertex Stimulation as a Control Site for Transcranial Magnetic Stimulation: A Concurrent TMS/fMRI Study.

    Science.gov (United States)

    Jung, JeYoung; Bungert, Andreas; Bowtell, Richard; Jackson, Stephen R

    2016-01-01

    A common control condition for transcranial magnetic stimulation (TMS) studies is to apply stimulation at the vertex. An assumption of vertex stimulation is that it has relatively little influence over on-going brain processes involved in most experimental tasks, however there has been little attempt to measure neural changes linked to vertex TMS. Here we directly test this assumption by using a concurrent TMS/fMRI paradigm in which we investigate fMRI blood-oxygenation-level-dependent (BOLD) signal changes across the whole brain linked to vertex stimulation. Thirty-two healthy participants to part in this study. Twenty-one were stimulated at the vertex, at 120% of resting motor threshold (RMT), with short bursts of 1 Hz TMS, while functional magnetic resonance imaging (fMRI) BOLD images were acquired. As a control condition, we delivered TMS pulses over the left primary motor cortex using identical parameters to 11 other participants. Vertex stimulation did not evoke increased BOLD activation at the stimulated site. By contrast we observed widespread BOLD deactivations across the brain, including regions within the default mode network (DMN). To examine the effects of vertex stimulation a functional connectivity analysis was conducted. The results demonstrated that stimulating the vertex with suprathreshold TMS reduced neural activity in brain regions related to the DMN but did not influence the functional connectivity of this network. Our findings provide brain imaging evidence in support of the use of vertex simulation as a control condition in TMS but confirm that vertex TMS induces regional widespread decreases in BOLD activation. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  8. Status of the silicon strip vertex detector for the Mark II experiment at the SLC

    International Nuclear Information System (INIS)

    Adolphsen, C.; Gratta, G.; Litke, A.

    1987-10-01

    We are constructing a silicon strip vertex detector to be used in the Mark II detector in the study of Z 0 decays at the SLAC Linear Collider. The status of the project, including the performance of the individual silicon detector modules, is presented. 6 refs., 8 figs., 2 tabs

  9. Approximations of Quantum-Graph Vertex Couplings by Singularly Scaled Rank-One Operators

    Czech Academy of Sciences Publication Activity Database

    Exner, Pavel; Manko, S. S.

    2014-01-01

    Roč. 104, č. 9 (2014), s. 1079-1094 ISSN 0377-9017 R&D Projects: GA ČR(CZ) GA14-06818S Institutional support: RVO:61389005 Keywords : quantum graph * vertex coupling * approximation Subject RIV: BE - Theoretical Physics Impact factor: 1.939, year: 2014

  10. Simple vertex correction improves G W band energies of bulk and two-dimensional crystals

    Science.gov (United States)

    Schmidt, Per S.; Patrick, Christopher E.; Thygesen, Kristian S.

    2017-11-01

    The G W self-energy method has long been recognized as the gold standard for quasiparticle (QP) calculations of solids in spite of the fact that the neglect of vertex corrections and the use of a density-functional theory starting point lack rigorous justification. In this work we remedy this situation by including a simple vertex correction that is consistent with a local-density approximation starting point. We analyze the effect of the self-energy by splitting it into short-range and long-range terms which are shown to govern, respectively, the center and size of the band gap. The vertex mainly improves the short-range correlations and therefore has a small effect on the band gap, while it shifts the band gap center up in energy by around 0.5 eV, in good agreement with experiments. Our analysis also explains how the relative importance of short- and long-range interactions in structures of different dimensionality is reflected in their QP energies. Inclusion of the vertex comes at practically no extra computational cost and even improves the basis set convergence compared to G W . Taken together, the method provides an efficient and rigorous improvement over the G W approximation.

  11. The silicon drift vertex detector for the STAR experiment at RHIC

    CERN Document Server

    Pandey, S U; Beuttenmüller, Rolf H; Caines, H; Chen, W; Dimassimo, D; Dyke, H; Elliot, D; Eremin, V; Grau, M; Hoffmann, G W; Humanic, T; Ilyashenko, Yu S; Kotov, I; Kraner, H W; Kuczewski, P; Leonhardt, B; Li, Z; Liaw, C J; Lo Curto, G; Middelkamp, P; Minor, R; Munhoz, M; Ott, G; Pruneau, C A; Rykov, V L; Schambach, J; Sedlmeir, J; Soja, B; Sugarbaker, E R; Takahashi, J; Wilson, K; Wilson, R

    2002-01-01

    The current status of the STAR Silicon Vertex Tracker (SVT) is presented. The performance of the Silicon Drift Detectors (SDD) is discussed. Results for a recent 15 layer SDD tracker which prototypes all components of the SVT are presented. The enhanced physics capabilities of the STAR detector due to the addition of the SVT are addressed.

  12. Behaviour of the cervix and the presenting vertex in labour in Blacks ...

    African Journals Online (AJOL)

    1974-04-17

    Apr 17, 1974 ... Behaviour of the Cervix and the Presenting. Vertex in Labour in Blacks and Indians of Natal ... man's curve of the normal progress of cervical dilatation in the first stage of labour to detect early deviation from .... the exact time of onset of painful regular uterine con- tractions. Doctors who recorded the results ...

  13. A general-purpose trigger processor system and its application to fast vertex trigger

    International Nuclear Information System (INIS)

    Hazumi, M.; Banas, E.; Natkaniec, Z.; Ostrowicz, W.

    1997-12-01

    A general-purpose hardware trigger system has been developed. The system comprises programmable trigger processors and pattern generator/samplers. The hardware design of the system is described. An application as a prototype of the very fast vertex trigger in an asymmetric B-factory at KEK is also explained. (author)

  14. On the Relation between Edge and Vertex Modelling in Shape Analysis

    DEFF Research Database (Denmark)

    Hobolth, Asger; Kent, John Thomas; Dryden, Ian L.

    2002-01-01

    Objects in the plane with no obvious landmarks can be described by either vertex transformation vectors or edge transformation vectors. In this paper we provide the relation between the two transformation vectors. Grenander & Miller (1994) use a multivariate normal distribution with a block circu...

  15. Exact Solution of the Six-Vertex Model with Domain Wall Boundary Conditions. Disordered Phase

    CERN Document Server

    Bleher, P M

    2005-01-01

    The six-vertex model, or the square ice model, with domain wall boundary conditions (DWBC) has been introduced and solved for finite $N$ by Korepin and Izergin. The solution is based on the Yang-Baxter equations and it represents the free energy in terms of an $N\\times N$ Hankel determinant. Paul Zinn-Justin observed that the Izergin-Korepin formula can be re-expressed in terms of the partition function of a random matrix model with a nonpolynomial interaction. We use this observation to obtain the large $N$ asymptotics of the six-vertex model with DWBC in the disordered phase. The solution is based on the Riemann-Hilbert approach and the Deift-Zhou nonlinear steepest descent method. As was noticed by Kuperberg, the problem of enumeration of alternating sign matrices (the ASM problem) is a special case of the the six-vertex model. We compare the obtained exact solution of the six-vertex model with known exact results for the 1, 2, and 3 enumerations of ASMs, and also with the exact solution on the so-called f...

  16. Conserved currents in the six-vertex and trigonometric solid-on-solid models

    Science.gov (United States)

    Ikhlef, Yacine; Weston, Robert

    2017-04-01

    We construct quasi-local conserved currents in the six-vertex model with anisotropy parameter η by making use of the quantum-group approach of Bernard and Felder. From these currents, we construct parafermionic operators with spin 1+\\text{i}η /π that obey a discrete-integral condition around lattice plaquettes embedded into the complex plane. These operators are identified with primary fields in a c  =  1 compactified free Boson conformal field theory. We then consider a vertex-face correspondence that takes the six-vertex model to a trigonometric SOS model, and construct SOS operators that are the image of the six-vertex currents under this correspondence. We define corresponding SOS parafermionic operators with spins s  =  1 and s=1+2\\text{i}η /π that obey discrete integral conditions around SOS plaquettes embedded into the complex plane. We consider in detail the cyclic-SOS case corresponding to the choice η =\\text{i}π ≤ft( p-{{p}\\prime}\\right)/p , with {{p}\\prime} coprime. We identify our SOS parafermionic operators in terms of the screening operators and primary fields of the associated c=1-6≤ft( p-{{p}\\prime}\\right){{}2}/p{{p}\\prime} conformal field theory.

  17. Vertex corrections to the mean-field electrical conductivity in disordered electron systems

    Czech Academy of Sciences Publication Activity Database

    Pokorný, Vladislav; Janiš, Václav

    2013-01-01

    Roč. 25, č. 17 (2013), "175502-1"-"175502-10" ISSN 0953-8984 Institutional support: RVO:68378271 Keywords : disordered electron systems * electrical conductivity * vertex corrections Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.223, year: 2013

  18. On the colour contribution to effective weak vertex in broken colour gauge theories

    International Nuclear Information System (INIS)

    Ramachandran, R.

    1979-01-01

    Treating the breaking of colour symmetry via the mixing between the colour gluons and weak bosons (a la Rajasekaran and Roy) it is observed that the colour contribution to the effective weak vertex of a quark at zero momentum transfer is zero upto 0(α). (author)

  19. Detecting overlapping community structure of networks based on vertex–vertex correlations

    International Nuclear Information System (INIS)

    Zarei, Mina; Izadi, Dena; Samani, Keivan Aghababaei

    2009-01-01

    Using the NMF (non-negative matrix factorization) method, the structure of overlapping communities in complex networks is investigated. For the feature matrix of the NMF method we introduce a vertex–vertex correlation matrix. The method is applied to some computer-generated and real-world networks. Simulations show that this feature matrix gives more reasonable results

  20. The Micro-Vertex-Detector for the P-bar ANDA experiment

    International Nuclear Information System (INIS)

    Zotti, Laura

    2013-01-01

    P-bar ANDA is a fixed target experiment that will be carried out at the future FAIR facility. P-bar ANDA will provide an excellent tool to address fundamental question in the field of hadronic physics, with a physic program that extends from the investigation of QCD (providing insight in the mechanisms of mass generation and confinement) to the test of fundamental symmetries. The Micro-Vertex-Detector located in the innermost part of the central tracking system will be composed by hybrid pixel and double-sided micro-strip silicon detectors. The Micro-Vertex-Detector will play an important role for the P-bar ANDA physics goals. The possibility to reconstruct the secondary vertices and the applicability of a precise D meson tagging is essential for the spectroscopy in the open charm sector and the charmonium mass region. To this aim the Micro-Vertex-Detector features a spatial resolution better than 100μm, a time resolution better than 20ns, a limited material budget, and a high data rate capability in a triggerless environment. An overview of the Micro-Vertex-Detector related to the physics goals will be presented.

  1. Selective attention and the auditory vertex potential. 1: Effects of stimulus delivery rate

    Science.gov (United States)

    Schwent, V. L.; Hillyard, S. A.; Galambos, R.

    1975-01-01

    Enhancement of the auditory vertex potentials with selective attention to dichotically presented tone pips was found to be critically sensitive to the range of inter-stimulus intervals in use. Only at the shortest intervals was a clear-cut enhancement of the latency component to stimuli observed for the attended ear.

  2. Sum rules for baryonic vertex functions and the proton wave function in QCD

    International Nuclear Information System (INIS)

    Lavelle, M.J.

    1985-01-01

    We consider light-cone sum rules for vertex functions involving baryon-meson couplings. These sum rules relate the non-perturbative, and experimentally known, coupling constants to the moments of the wave function of the proton state. Our results for these moments are consistent with those obtained from QCD sum rules for two-point functions. (orig.)

  3. Proposed method of assembly for the BCD silicon strip vertex detector modules

    International Nuclear Information System (INIS)

    Lindenmeyer, C.

    1989-01-01

    The BCD Silicon strip Vertex Detector is constructed of 10 identical central region modules and 18 similar forward region modules. This memo describes a method of assembling these modules from individual silicon wafers. Each wafer is fitted with associated front end electronics and cables and has been tested to insure that only good wafers reach the final assembly stage. 5 figs

  4. On non-Cayley vertex-transitive graphs and the Meta-Cayley graphs ...

    African Journals Online (AJOL)

    The pursuit to identify vertex-transitive non-Cayley graphs has been deliberate for some time now. In that vein, Alspach and Parsons [1] introduced metacirculant graphs. They are de ned on two cyclic groups with adjacency re-sembling twisting that is typically used in de ning semi-direct products of groups. In this sequel we ...

  5. Study of a DEPFET vertex detector and of supersymmetric smuons at the ILC

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xun

    2009-01-21

    This thesis is devoted to the study of the performance of a pixel vertex detector based on DEPFET technology at the International Linear Collider (ILC). The ILC is the proposed next generation e{sup +}e{sup -} collider to explore the physics at the Terascale. At the ILC with its well-defined initial state of collisions, possible discoveries at the Large Hadron Collider can be verified and studied more accurately. It is expected that the precision measurements of the ILC will answer many fundamental questions about the universe, such as the generation of particle masses and the origin of electroweak spontaneous symmetry breaking. The ambitious physics goals present challenges to the ILC detectors. Several detector concepts have been proposed in recent years. A crucial device for all these concepts is the pixel vertex detector. It provides precise impact parameter information of charged particles, jet flavor tagging and improves overall tracking efficiency. To meet the requirements of the ILC environment, the vertex detector will be arranged in a concentric multi-layer array around the interaction point to cover as large a solid angle as possible. Endcap disks are considered in some designs. Silicon pixel sensor technologies must be employed to provide excellent point resolution. The DEPFET technology, which integrates the first level of amplification into a depleted silicon bulk, is one of the promising candidates. The DEPFET sensor is very sensitive with a high signal-to-noise ratio. Power consumption is minimized due to the internal storage of signal charges. The good radiation tolerance makes it capable of working close to the interaction point. In this thesis, we discuss the detailed simulation of the DEPFET vertex detector, following the general vertex detector layout proposed by the TESLA collaboration. The simulation is used to evaluate the impact parameter resolution. We also discuss the DEPFET test beam analysis on two-track resolution. The whole analysis

  6. Study of a DEPFET vertex detector and of supersymmetric smuons at the ILC

    International Nuclear Information System (INIS)

    Chen, Xun

    2009-01-01

    This thesis is devoted to the study of the performance of a pixel vertex detector based on DEPFET technology at the International Linear Collider (ILC). The ILC is the proposed next generation e + e - collider to explore the physics at the Terascale. At the ILC with its well-defined initial state of collisions, possible discoveries at the Large Hadron Collider can be verified and studied more accurately. It is expected that the precision measurements of the ILC will answer many fundamental questions about the universe, such as the generation of particle masses and the origin of electroweak spontaneous symmetry breaking. The ambitious physics goals present challenges to the ILC detectors. Several detector concepts have been proposed in recent years. A crucial device for all these concepts is the pixel vertex detector. It provides precise impact parameter information of charged particles, jet flavor tagging and improves overall tracking efficiency. To meet the requirements of the ILC environment, the vertex detector will be arranged in a concentric multi-layer array around the interaction point to cover as large a solid angle as possible. Endcap disks are considered in some designs. Silicon pixel sensor technologies must be employed to provide excellent point resolution. The DEPFET technology, which integrates the first level of amplification into a depleted silicon bulk, is one of the promising candidates. The DEPFET sensor is very sensitive with a high signal-to-noise ratio. Power consumption is minimized due to the internal storage of signal charges. The good radiation tolerance makes it capable of working close to the interaction point. In this thesis, we discuss the detailed simulation of the DEPFET vertex detector, following the general vertex detector layout proposed by the TESLA collaboration. The simulation is used to evaluate the impact parameter resolution. We also discuss the DEPFET test beam analysis on two-track resolution. The whole analysis procedures

  7. Modeling, Measurements, and Fundamental Database Development for Nonequilibrium Hypersonic Aerothermodynamics

    Science.gov (United States)

    Bose, Deepak

    2012-01-01

    The design of entry vehicles requires predictions of aerothermal environment during the hypersonic phase of their flight trajectories. These predictions are made using computational fluid dynamics (CFD) codes that often rely on physics and chemistry models of nonequilibrium processes. The primary processes of interest are gas phase chemistry, internal energy relaxation, electronic excitation, nonequilibrium emission and absorption of radiation, and gas-surface interaction leading to surface recession and catalytic recombination. NASAs Hypersonics Project is advancing the state-of-the-art in modeling of nonequilibrium phenomena by making detailed spectroscopic measurements in shock tube and arcjets, using ab-initio quantum mechanical techniques develop fundamental chemistry and spectroscopic databases, making fundamental measurements of finite-rate gas surface interactions, implementing of detailed mechanisms in the state-of-the-art CFD codes, The development of new models is based on validation with relevant experiments. We will present the latest developments and a roadmap for the technical areas mentioned above

  8. Work fluctuation and total entropy production in nonequilibrium processes.

    Science.gov (United States)

    Funo, Ken; Shitara, Tomohiro; Ueda, Masahito

    2016-12-01

    Work fluctuation and total entropy production play crucial roles in small thermodynamic systems subject to large thermal fluctuations. We investigate a trade-off relation between them in a nonequilibrium situation in which a system starts from an arbitrary nonequilibrium state. We apply a variational method to study this problem and find a stationary solution against variations over protocols that describe the time dependence of the Hamiltonian of the system. Using the stationary solution, we find the minimum of the total entropy production for a given amount of work fluctuation. An explicit protocol that achieves this is constructed from an adiabatic process followed by a quasistatic process. The obtained results suggest how one can control the nonequilibrium dynamics of the system while suppressing its work fluctuation and total entropy production.

  9. Nonequilibrium Dynamical Mean-Field Theory for Bosonic Lattice Models

    Directory of Open Access Journals (Sweden)

    Hugo U. R. Strand

    2015-03-01

    Full Text Available We develop the nonequilibrium extension of bosonic dynamical mean-field theory and a Nambu real-time strong-coupling perturbative impurity solver. In contrast to Gutzwiller mean-field theory and strong-coupling perturbative approaches, nonequilibrium bosonic dynamical mean-field theory captures not only dynamical transitions but also damping and thermalization effects at finite temperature. We apply the formalism to quenches in the Bose-Hubbard model, starting from both the normal and the Bose-condensed phases. Depending on the parameter regime, one observes qualitatively different dynamical properties, such as rapid thermalization, trapping in metastable superfluid or normal states, as well as long-lived or strongly damped amplitude oscillations. We summarize our results in nonequilibrium “phase diagrams” that map out the different dynamical regimes.

  10. Inviscid flux-splitting algorithms for real gases with non-equilibrium chemistry

    Science.gov (United States)

    Shuen, Jian-Shun; Liou, Meng-Sing; Van Leer, Bram

    1990-01-01

    Formulations of inviscid flux splitting algorithms for chemical nonequilibrium gases are presented. A chemical system for air dissociation and recombination is described. Numerical results for one-dimensional shock tube and nozzle flows of air in chemical nonequilibrium are examined.

  11. Nonequilibrium Statistical Mechanics in One Dimension

    Science.gov (United States)

    Privman, Vladimir

    2005-08-01

    Part I. Reaction-Diffusion Systems and Models of Catalysis; 1. Scaling theories of diffusion-controlled and ballistically-controlled bimolecular reactions S. Redner; 2. The coalescence process, A+A->A, and the method of interparticle distribution functions D. ben-Avraham; 3. Critical phenomena at absorbing states R. Dickman; Part II. Kinetic Ising Models; 4. Kinetic ising models with competing dynamics: mappings, correlations, steady states, and phase transitions Z. Racz; 5. Glauber dynamics of the ising model N. Ito; 6. 1D Kinetic ising models at low temperatures - critical dynamics, domain growth, and freezing S. Cornell; Part III. Ordering, Coagulation, Phase Separation; 7. Phase-ordering dynamics in one dimension A. J. Bray; 8. Phase separation, cluster growth, and reaction kinetics in models with synchronous dynamics V. Privman; 9. Stochastic models of aggregation with injection H. Takayasu and M. Takayasu; Part IV. Random Sequential Adsorption and Relaxation Processes; 10. Random and cooperative sequential adsorption: exactly solvable problems on 1D lattices, continuum limits, and 2D extensions J. W. Evans; 11. Lattice models of irreversible adsorption and diffusion P. Nielaba; 12. Deposition-evaporation dynamics: jamming, conservation laws and dynamical diversity M. Barma; Part V. Fluctuations In Particle and Surface Systems; 13. Microscopic models of macroscopic shocks S. A. Janowsky and J. L. Lebowitz; 14. The asymmetric exclusion model: exact results through a matrix approach B. Derrida and M. R. Evans; 15. Nonequilibrium surface dynamics with volume conservation J. Krug; 16. Directed walks models of polymers and wetting J. Yeomans; Part VI. Diffusion and Transport In One Dimension; 17. Some recent exact solutions of the Fokker-Planck equation H. L. Frisch; 18. Random walks, resonance, and ratchets C. R. Doering and T. C. Elston; 19. One-dimensional random walks in random environment K. Ziegler; Part VII. Experimental Results; 20. Diffusion

  12. Nonequilibrium Energetics of Single Molecule Motor, Kinesin-1

    Science.gov (United States)

    Ariga, Takayuki; Tomishige, Michio; Mizuno, Daisuke

    2018-02-01

    Molecular motors are nonequilibrium open systems that convert chemical energy to mechanical work. Here we investigate the nonequilibrium energetics of a single molecule kinesin by measuring the motion of an attached probe particle and its response to external forces with optical tweezers. The sum of the heat dissipation estimated from the violation of the fluctuation-response relation and the output power was inconsistent with the input free energy rate, implying that internal dissipation is dominant. By using a two-state Markov model, we discuss the energy flow of the kinesin motor.

  13. Generalization of the second law for a nonequilibrium initial state

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, H.-H., E-mail: hhh@mx.ibaraki.ac.j [Department of Mathematical Sciences, Ibaraki University, Bunkyo, Mito 310-8512 (Japan); Ishikawa, J.; Takara, K. [Department of Mathematical Sciences, Ibaraki University, Bunkyo, Mito 310-8512 (Japan); Driebe, D.J. [Division of Math, Science and Technology, Nova Southeastern University, Fort Lauderdale, FL 33314 (United States)

    2010-02-08

    We generalize the second law of thermodynamics in its maximum work formulation for a nonequilibrium initial distribution. It is found that in an isothermal process, the Boltzmann relative entropy (H-function) is not just a Lyapunov function but also tells us the maximum work that may be gained from a nonequilibrium initial state. The generalized second law also gives a fundamental relation between work and information. It is valid even for a small Hamiltonian system not in contact with a heat reservoir but with an effective temperature determined by the isentropic condition. Our relation can be tested in the Szilard engine, which will be realized in the laboratory.

  14. Limiting processes in non-equilibrium classical statistical mechanics

    International Nuclear Information System (INIS)

    Jancel, R.

    1983-01-01

    After a recall of the basic principles of the statistical mechanics, the results of ergodic theory, the transient at the thermodynamic limit and his link with the transport theory near the equilibrium are analyzed. The fundamental problems put by the description of non-equilibrium macroscopic systems are investigated and the kinetic methods are stated. The problems of the non-equilibrium statistical mechanics are analyzed: irreversibility and coarse-graining, macroscopic variables and kinetic description, autonomous reduced descriptions, limit processes, BBGKY hierarchy, limit theorems [fr

  15. Imaginary-time formulation of strongly correlated nonequilibrium

    Science.gov (United States)

    Heary, Ryan Joseph

    Strongly correlated nanostructures and lattices of electrons are studied when these systems reside in a steady-state nonequilibrium. Much of the work done to date has made use of the nonequilibrium real-time Keldysh Green function technique. These methods include: the Keldysh Green function perturbation theory, time-dependent numerical renormalization group, density matrix renormalization group, and diagrammatic quantum Monte Carlo. In the special case of steady-state nonequilibrium we construct an imaginary-time theory. The motivation to do this is simple: there exist an abundant number of well-established strongly correlated computational solvers for imaginary-time theory and perturbation theory on the imaginary-time contour is much more straightforward than that of the real-time contour. The first model system we focus on is a strongly interacting quantum dot situated between source and drain electron reservoirs. The steady-state nonequilibrium boundary condition is established by applying a voltage bias phi across the reservoirs, in turn modifying the chemical potentials of the leads. For a symmetric voltage drop we have mu source = phi/2 and mudrain = -phi/2. The dynamics of the electrons are governed by the Hamiltonian Ĥ which is inherently independent of the imbalance in the source and drain chemical potentials. The statistics though are determined by the operator Ĥ-Ŷ , where Ŷ imposes the nonequilibrium boundary condition. We show that it is possible to construct a single effective Hamiltonian K̂ able to describe both the dynamics and statistics of the system. Upon formulating the theory we explicitly show that it is consistent with the real-time Keldysh theory both formally and through an example using perturbation theory. In these systems there exists a strong interplay between the interactions and nonequilibrium leading to novel nonperturbative phenomena. Therefore, we combine our theory with the Hirsch-Fye quantum Monte Carlo algorithm to study

  16. Time Dependent Hartree Fock Equation: Gateway to Nonequilibrium Plasmas

    International Nuclear Information System (INIS)

    Dufty, James W.

    2007-01-01

    This is the Final Technical Report for DE-FG02-2ER54677 award 'Time Dependent Hartree Fock Equation - Gateway to Nonequilibrium Plasmas'. Research has focused on the nonequilibrium dynamics of electrons in the presence of ions, both via basic quantum theory and via semi-classical molecular dynamics (MD) simulation. In addition, fundamental notions of dissipative dynamics have been explored for models of grains and dust, and for scalar fields (temperature) in turbulent edge plasmas. The specific topics addressed were Quantum Kinetic Theory for Metallic Clusters, Semi-classical MD Simulation of Plasmas , and Effects of Dissipative Dynamics.

  17. Nonequilibrium work energy relation for non-Hamiltonian dynamics.

    Science.gov (United States)

    Mandal, Dibyendu; DeWeese, Michael R

    2016-04-01

    Recent years have witnessed major advances in our understanding of nonequilibrium processes. The Jarzynski equality, for example, provides a link between equilibrium free energy differences and finite-time nonequilibrium dynamics. We propose a generalization of this relation to non-Hamiltonian dynamics, relevant for active matter systems, continuous feedback, and computer simulation. Surprisingly, this relation allows us to calculate the free energy difference between the desired initial and final equilibrium states using arbitrary dynamics. As a practical matter, this dissociation between the dynamics and the initial and final states promises to facilitate a range of techniques for free energy estimation in a single universal expression.

  18. Convection with local thermal non-equilibrium and microfluidic effects

    CERN Document Server

    Straughan, Brian

    2015-01-01

    This book is one of the first devoted to an account of theories of thermal convection which involve local thermal non-equilibrium effects, including a concentration on microfluidic effects. The text introduces convection with local thermal non-equilibrium effects in extraordinary detail, making it easy for readers newer to the subject area to understand. This book is unique in the fact that it addresses a large number of convection theories and provides many new results which are not available elsewhere. This book will be useful to researchers from engineering, fluid mechanics, and applied mathematics, particularly those interested in microfluidics and porous media.

  19. An antiperiodic dynamical six-vertex model: I. Complete spectrum by SOV, matrix elements of the identity on separate states and connections to the periodic eight-vertex model

    International Nuclear Information System (INIS)

    Niccoli, G

    2013-01-01

    The spin-1/2 highest weight representations of the dynamical six-vertex and the standard eight-vertex Yang–Baxter algebra on a finite chain are considered in this paper. In particular, the integrable quantum models associated with the corresponding transfer matrices under antiperiodic boundary conditions for the dynamical six-vertex case and periodic boundary conditions for the eight-vertex case are analyzed here. For the antiperiodic dynamical six-vertex transfer matrix defined on chains with an odd number of sites, we adapt Sklyanin’s quantum separation of variable (SOV) method and explicitly construct the SOV representations from the original space of the representations. In this way, we provide the complete characterization of the eigenvalues and the eigenstates proving also the simplicity of its spectrum. Moreover, we characterize the matrix elements of the identity on separated states of this model by determinant formulae. The matrices entering these determinants have elements given by sums over the SOV spectrum of the product of the coefficients of the separate states. This SOV analysis is done without any need to be reduced to the case of the so-called elliptic roots of unit, and the results derived here define the required setup to extend to the dynamical six-vertex model the approach recently developed by the author and collaborators to compute the form factors of the local operators in the SOV framework. For the periodic eight-vertex transfer matrix, we prove that its eigenvalues have to satisfy a fixed system of equations. In the case of a chain with an odd number of sites, this system of equations is the same entering in the SOV characterization of the antiperiodic dynamical six-vertex transfer matrix spectrum. This implies that the set of the periodic eight-vertex eigenvalues is contained in the set of the antiperiodic dynamical six-vertex eigenvalues. A criterion is introduced to find simultaneous eigenvalues of these two transfer matrices and

  20. Some recent developments in non-equilibrium statistical physics

    Indian Academy of Sciences (India)

    for molecular motors and the asymmetric exclusion process which is a basic example of a driven lattice gas. Keywords. Thermodynamics; non-equilibrium mechanics; Brownian motion; molecular motors; Gallavotti–Cohen fluctuation theorem; Jarzynski's work relation. PACS Nos 05.70.Ln; 05.40.-a; 87.16.Nn. 1. Introduction.

  1. Conserving GW scheme for nonequilibrium quantum transport in molecular contacts

    DEFF Research Database (Denmark)

    Thygesen, Kristian Sommer; Rubio, Angel

    2008-01-01

    We give a detailed presentation of our recent scheme to include correlation effects in molecular transport calculations using the nonequilibrium Keldysh formalism. The scheme is general and can be used with any quasiparticle self-energy, but for practical reasons, we mainly specialize to the so-c...

  2. Spacecraft Sterilization Using Non-Equilibrium Atmospheric Pressure Plasma

    Science.gov (United States)

    Cooper, Moogega; Vaze, Nachiket; Anderson, Shawn; Fridman, Gregory; Vasilets, Victor N.; Gutsol, Alexander; Tsapin, Alexander; Fridman, Alexander

    2007-01-01

    As a solution to chemically and thermally destructive sterilization methods currently used for spacecraft, non-equilibrium atmospheric pressure plasmas are used to treat surfaces inoculated with Bacillus subtilis and Deinococcus radiodurans. Evidence of significant morphological changes and reduction in viability due to plasma exposure will be presented, including a 4-log reduction of B. subtilis after 2 minutes of dielectric barrier discharge treatment.

  3. Canonical structure of dynamical fluctuations in mesoscopic nonequilibrium steady states

    Czech Academy of Sciences Publication Activity Database

    Maes, C.; Netočný, Karel

    2008-01-01

    Roč. 82, č. 3 (2008), 30003/1-30003/6 ISSN 0295-5075 R&D Projects: GA ČR GC202/07/J051 Institutional research plan: CEZ:AV0Z10100520 Keywords : nonequilibrium fluctuations * steady state * Onsager- Machlup theory Subject RIV: BE - Theoretical Physics Impact factor: 2.203, year: 2008

  4. Fluctuations and large deviations in non-equilibrium systems

    Indian Academy of Sciences (India)

    a possible way of extending the notion of free energy to non-equilibrium systems. This large deviation function of the density can be calculated explicitly for exclusion models in one dimension with open boundary conditions. For these models, one can also obtain the distribution of the current of particles flowing through the ...

  5. Nonequilibrium relaxation method – An alternative simulation strategy

    Indian Academy of Sciences (India)

    the results to infinite system. This equilibrium method traces over the standard theory of the thermal statistical mechanics, and over the idea of the thermodynamic limit. Recently, an alternative simulation strategy has been developed, which analyzes the nonequilibrium relaxation (NER) process. It is called the NER method.

  6. Nonequilibrium Enhances Adaptation Efficiency of Stochastic Biochemical Systems.

    Directory of Open Access Journals (Sweden)

    Chen Jia

    Full Text Available Adaptation is a crucial biological function possessed by many sensory systems. Early work has shown that some influential equilibrium models can achieve accurate adaptation. However, recent studies indicate that there are close relationships between adaptation and nonequilibrium. In this paper, we provide an explanation of these two seemingly contradictory results based on Markov models with relatively simple networks. We show that as the nonequilibrium driving becomes stronger, the system under consideration will undergo a phase transition along a fixed direction: from non-adaptation to simple adaptation then to oscillatory adaptation, while the transition in the opposite direction is forbidden. This indicates that although adaptation may be observed in equilibrium systems, it tends to occur in systems far away from equilibrium. In addition, we find that nonequilibrium will improve the performance of adaptation by enhancing the adaptation efficiency. All these results provide a deeper insight into the connection between adaptation and nonequilibrium. Finally, we use a more complicated network model of bacterial chemotaxis to validate the main results of this paper.

  7. Fluctuations and large deviations in non-equilibrium systems

    Indian Academy of Sciences (India)

    For systems in contact with two reservoirs at different densities or with two thermostats at different temperatures, the large deviation function of the density gives a possible way of extending the notion of free energy to non-equilibrium systems. This large deviation function of the density can be calculated explicitly for ...

  8. Principle of Entropy Maximization for Nonequilibrium Steady States

    DEFF Research Database (Denmark)

    Shapiro, Alexander; Stenby, Erling Halfdan

    2002-01-01

    The goal of this contribution is to find out to what extent the principle of entropy maximization, which serves as a basis for the equilibrium thermodynamics, may be generalized onto non-equilibrium steady states. We prove a theorem that, in the system of thermodynamic coordinates, where entropy...

  9. Coherence enhanced quantum metrology in a nonequilibrium optical molecule

    Science.gov (United States)

    Wang, Zhihai; Wu, Wei; Cui, Guodong; Wang, Jin

    2018-03-01

    We explore the quantum metrology in an optical molecular system coupled to two environments with different temperatures, using a quantum master equation beyond secular approximation. We discover that the steady-state coherence originating from and sustained by the nonequilibrium condition can enhance quantum metrology. We also study the quantitative measures of the nonequilibrium condition in terms of the curl flux, heat current and entropy production at the steady state. They are found to grow with temperature difference. However, an apparent paradox arises considering the contrary behaviors of the steady-state coherence and the nonequilibrium measures in relation to the inter-cavity coupling strength. This paradox is resolved by decomposing the heat current into a population part and a coherence part. Only the latter, the coherence part of the heat current, is tightly connected to the steady-state coherence and behaves similarly with respect to the inter-cavity coupling strength. Interestingly, the coherence part of the heat current flows from the low-temperature reservoir to the high-temperature reservoir, opposite to the direction of the population heat current. Our work offers a viable way to enhance quantum metrology for open quantum systems through steady-state coherence sustained by the nonequilibrium condition, which can be controlled and manipulated to maximize its utility. The potential applications go beyond quantum metrology and extend to areas such as device designing, quantum computation and quantum technology in general.

  10. D.C.-arc plasma generator for nonequilibrium plasmachemical processes

    International Nuclear Information System (INIS)

    Kvaltin, J.

    1990-06-01

    The analysis is made of the conditions for generation of nonequilibrium plasma in a plasmachemical reactor, and the design is described of a d.c. arc plasma generator based on the integral criterion. Results of measuring potentials on the plasma column of this generator are presented. (author)

  11. On the theory of non-equilibrium hydrodynamic fluctuations

    International Nuclear Information System (INIS)

    Peletminskij, S.V.; Plokhov, S.S.; Prikhod'ko, V.I.

    1981-01-01

    Using the method of abbreviated description a microscopic theory of non-equilibrium fluctuations with a great radius of correlations, which permits to study fluctuation kinetics at t>>tausub(r)(tausub(r) is relaxation time) is built. General formula, describing the degree character of approximation to the state of statistical equilibrium of mean values of arbitrary quasilocal operators, are obtained [ru

  12. Electron systems out of equilibrium: nonequilibrium Green's function approach

    Czech Academy of Sciences Publication Activity Database

    Špička, Václav; Velický, Bedřich; Kalvová, Anděla

    2014-01-01

    Roč. 28, č. 23 (2014), "1430013-1"-"1430013-103" ISSN 0217-9792 R&D Projects: GA ČR GAP204/12/0897 Institutional support: RVO:68378271 Keywords : nonequilibrium statistical physics * transients * quantum transport theory Subject RIV: BE - Theoretical Physics Impact factor: 0.937, year: 2014

  13. Classical Orbital Paramagnetism in Non-equilibrium Steady State

    Indian Academy of Sciences (India)

    Avinash A. Deshpande

    2017-09-12

    Sep 12, 2017 ... Classical Orbital Paramagnetism in Non-equilibrium Steady State. AVINASH A. DESHPANDE. ∗ and N. KUMAR. Raman Research Institute, Bangalore 560 080, India. ∗. Corresponding author. E-mail: desh@rri.res.in. MS received 25 March 2017; accepted 31 July 2017; published online 12 September ...

  14. Fluctuation theorems and orbital magnetism in nonequilibrium state

    Indian Academy of Sciences (India)

    We study Langevin dynamics of a driven charged particle in the presence as well as in the absence of magnetic field. We discuss the validity of various work fluctuation theorems using different model potentials and external drives. We also show that one can generate an orbital magnetic moment in a nonequilibrium state ...

  15. Fluctuation theorems and orbital magnetism in nonequilibrium state

    Indian Academy of Sciences (India)

    Fluctuation theorem; Jarzynski equality; orbital magnetism. PACS Nos 05.70.Ln; 05.40.Jc; 05.40.-a; 05.40.Ca. 1. Introduction. Recent developments in nonequilibrium statistical mechanics has led to the discov- ery of several rigorous theorems for systems far away from equilibrium [1–10]. The fluctuation theorems describe ...

  16. Simulation and comparison of equilibrium and nonequilibrium stage ...

    African Journals Online (AJOL)

    In the present study, two distinctly different approaches are followed for modelling of reactive distillation column, the equilibrium stage model and the nonequilibrium stage model. These models are simulated with a computer code developed in the present study using MATLAB programming. In the equilibrium stage models, ...

  17. On the forces and fluxes in non-equilibrium thermodynamics

    International Nuclear Information System (INIS)

    Kitahara, Kazuo

    1986-01-01

    A formulation of non-equilibrium thermodynamics of continuum systems based on local equilibrium assumption is reported. Thermodynamic forces are defined from a generalized local entropy and irreversible fluxes are defined as non-advective parts of fluxes of conservative quantities. The validity of the general evolution criterion and its generalization is discussed. (author)

  18. Power pulsing scheme for analog and digital electronics of the vertex detectors at CLIC

    CERN Document Server

    Blanchot, Georges

    2015-01-01

    The precision requirements of the vertex detector at CLIC impose strong limitations on the mass of such a detector (< 0.2% of a radiation length, Xo, per layer). To achieve such a low material budget, ultra-thin hybrid pixel detectors are foreseen, while the mass for cooling and services will be reduced by implementing a power pulsing scheme that takes advantage of the low duty cycle of the accelerator. The principal aim is to achieve significant power reduction without compromising the power integrity supplied to the front-end electronics. This report summarises the study of a power pulsing scheme to power the vertex barrel electronics of the future CLIC experiment. Its main goal is to describe in more detail what has been already presented in TWEPP conferences and other presentations. The report can therefore serve as an operator manual for future use and development of the system

  19. Active Vertex Model for cell-resolution description of epithelial tissue mechanics.

    Directory of Open Access Journals (Sweden)

    Daniel L Barton

    2017-06-01

    Full Text Available We introduce an Active Vertex Model (AVM for cell-resolution studies of the mechanics of confluent epithelial tissues consisting of tens of thousands of cells, with a level of detail inaccessible to similar methods. The AVM combines the Vertex Model for confluent epithelial tissues with active matter dynamics. This introduces a natural description of the cell motion and accounts for motion patterns observed on multiple scales. Furthermore, cell contacts are generated dynamically from positions of cell centres. This not only enables efficient numerical implementation, but provides a natural description of the T1 transition events responsible for local tissue rearrangements. The AVM also includes cell alignment, cell-specific mechanical properties, cell growth, division and apoptosis. In addition, the AVM introduces a flexible, dynamically changing boundary of the epithelial sheet allowing for studies of phenomena such as the fingering instability or wound healing. We illustrate these capabilities with a number of case studies.

  20. Use of a track and vertex processor in a fixed-target charm experiment

    International Nuclear Information System (INIS)

    Schub, M.H.; Carey, T.A.; Hsiung, Y.B.; Kaplan, D.M.; Lee, C.; Miller, G.; Sa, J.; Teng, P.K.

    1996-01-01

    We have constructed and operated a high-speed parallel-pipelined track and vertex processor and used it to trigger data acquisition in a high-rate charm and beauty experiment at Fermilab. The processor uses information from hodoscopes and wire chambers to reconstruct tracks in the bend view of a magnetic spectrometer, and uses these tracks to find the corresponding tracks in a set of silicon-strip detectors. The processor then forms vertices and triggers the experiment if at least one vertex is downstream of the target. Under typical charm running conditions, with an interaction rate of ∼5 MHz, the processor rejects 80-90% of lower-level triggers while maintaining efficiency of ∼70% for two-prong D-meson decays. (orig.)

  1. Cell-vertex discretization of shallow water equations on mixed unstructured meshes

    Science.gov (United States)

    Danilov, Sergey; Androsov, Alexey

    2015-04-01

    Finite-volume discretizations can be formulated on unstructured meshes composed of different polygons. A staggered cell-vertex finite-volume discretization, keeping the velocity degrees of freedom on cell centroids and scalar degrees of freedom on vertices, presents one possible choice. Its performance is analyzed on mixed meshes composed of triangles and quads. Although triangular meshes are most flexible geometrically, quads are more efficient numerically and do not support spurious inertial modes of the triangular cell-vertex discretization. Mixed meshes composed of triangles and quads combine benefits of both. In particular, triangular transitional zones can be used to join quadrilateral meshes of differing resolution, i. e., to provide smooth nesting of a fine mesh into a coarse one. Based on a set of examples involving shallow water equations it is shown that mixed meshes offer a viable approach provided some background biharmonic viscosity (or the biharmonic filter) is used to stabilize the triangular part of the mesh.

  2. Hadron-quark vertex function. Interconnection between 3D and 4D wave function

    International Nuclear Information System (INIS)

    Mitra, A.N.; Bhatnagar, S.

    1990-01-01

    Interconnection between 3D and 4D forms of Bethe-Salpeter equation (EBS) with a kernel depending on relative momenta is used to derive hadron-quark vertex function in Lorentz invariance form. The vertex function which is directly related to a 4D wave function satisfying a corresponding EBS determines the natural continuation outside mass surface for the entire momentum space and serves the basis for computing amplitudes of transitions through appropriate loop quark diagrams. Two applications (f p values for P→ll-bar and F π for n 0 +yy) are discussed briefly to illustrate this formalism. An attention is paid to the problem of complex amplitudes for quark loops with a larger number of external hadrons.A possible solution of the problem is proposed. 29 refs

  3. Active Vertex Model for cell-resolution description of epithelial tissue mechanics.

    Science.gov (United States)

    Barton, Daniel L; Henkes, Silke; Weijer, Cornelis J; Sknepnek, Rastko

    2017-06-01

    We introduce an Active Vertex Model (AVM) for cell-resolution studies of the mechanics of confluent epithelial tissues consisting of tens of thousands of cells, with a level of detail inaccessible to similar methods. The AVM combines the Vertex Model for confluent epithelial tissues with active matter dynamics. This introduces a natural description of the cell motion and accounts for motion patterns observed on multiple scales. Furthermore, cell contacts are generated dynamically from positions of cell centres. This not only enables efficient numerical implementation, but provides a natural description of the T1 transition events responsible for local tissue rearrangements. The AVM also includes cell alignment, cell-specific mechanical properties, cell growth, division and apoptosis. In addition, the AVM introduces a flexible, dynamically changing boundary of the epithelial sheet allowing for studies of phenomena such as the fingering instability or wound healing. We illustrate these capabilities with a number of case studies.

  4. Exploratory study of the three-gluon vertex on the lattice

    Energy Technology Data Exchange (ETDEWEB)

    Parrinello, C. (Department of Physics and Astronomy, University of Edinburgh, Mayfield Road, Edinburgh EH93JZ (United Kingdom))

    1994-10-01

    We define and evaluate on the lattice the amputated three-gluon vertex function in momentum space. We give numerical results for 16[sup 3][times]40 and 24[sup 3][times]40 quenched lattices at [beta]=6.0. A good numerical signal is obtained at the price of enforcing the gauge-fixing condition with high accuracy. By comparing results from two different lattice volumes, we try to investigate the crucial issue of finite volume effects. We also outline a method for the lattice evaluation of the QCD running coupling as defined from the three-gluon vertex, while being aware that a realistic calculation will require larger [beta] values and very high statistics.

  5. Measuring the WWγ vertex in single W production at ep colliders

    International Nuclear Information System (INIS)

    Baur, U.; Zeppenfeld, D.

    1989-01-01

    A detailed analysis of single W production in ep collisions via ep→eW ± X is presented by using helicity amplitudes for general WWγ couplings. Analytic expressions are given for the γq→W ± q' helicity amplitudes which describe ep→eWX in the Weizsaecker-Williams approximation and provide a semiquantitative understanding of the results obtained with the full matrix elements. Possibilities to test the gauge theory structure of the WWγ vertex at HERA (√s=314 GeV) and at an ep collider in the LEP tunnel (√s≅1.4 TeV) are explored. It is found that at HERA the WWγ vertex can be measured with 30-50% accuracy after a few years of running. (orig.)

  6. Comparison of vertex analysis and branching ratio in the study of trees.

    Science.gov (United States)

    Horsfield, K; Woldenberg, M J

    1986-08-01

    Many kinds of naturally occurring trees have been the subject of study by investigators from a wide variety of disciplines, employing different techniques each with its own advantages and disadvantages. In this paper two such techniques for studying trees are compared: one is the classification of branches by order and the calculation of the branching ratio; the other is vertex analysis. The two methods, which at first sight appear different, are found to be mathematically similar. In complete trees, much the same information can be obtained from counting branches in each order as can be obtained from vertex analysis. In the case of pruned trees, overall branching ratio may give the more consistent results.

  7. A Future Vertex Locator with Precise Timing for the LHCb Experiment

    CERN Multimedia

    Mitreska, Biljana

    2017-01-01

    The LHCb experiment is designed to perform high precision measurements of matter-antimatter asymmetries and searches for rare and forbidden decays, with the aim of discovering new and unexpected particles and forces. In 2030 the LHC beam intensity will increase by a factor of 50 compared to current operations. This means increased samples of the particles we need to study, but it also presents experimental challenges. In particular, with current technology it becomes impossible to differentiate the many (>50) separate proton-proton collisions which occur for each bunch crossing. A Monte Carlo simulation was developed to model the operation of a silicon pixel vertex detector surrounding the collision region at LHCb, under the conditions expected after 2030, after the second upgrade of the Vertex Locator (VELO). The main goal was studying the effect of adding '4D' detectors which save high-precision timing information, in addition to the usual three spatial coordinates, as charged particles pass through them. W...

  8. The vertex detector of the UA2 experiment (a low mass self sustaining system of cylindrical multiwire proportional chambers)

    International Nuclear Information System (INIS)

    Dialinas, M.; Forget, J.; Geoffroy, D.; Jean, P.; Vergand, M.

    1983-07-01

    The construction of the cylindrical proportional strip chambers of the UA2 vertex detector is reported. The mechanical design, the engineering and the effective realization are described in detail. Possible improvements for the construction of such chambers are also given

  9. The SLD Vertex Detector Upgrade (VXD3) and a study of b anti bg events

    International Nuclear Information System (INIS)

    Dervan, P.J.

    1998-04-01

    This thesis presents a variety of work concerning the design, construction and use of the SLD's vertex detector. SLD's pioneering 120 Mpixel vertex detector, VXD2, was replaced by VXD3, a 307Mpixel CCD vertex detector in january 1996. The motivation for the up-grade detector and its subsequent construction and testing are described in some detail. This work represents the collaborative work of a large number of people. The authors' work was mainly carried out at EEV on the testing of the CCDs and subsequent ladders. VXD3 was commissioned during the 1996 SLD run and performed very close to design specifications. Monitoring the position of VXD3 is crucial for reconstructing the data in the detector for physics analysis. This was carried out using a capacitive wire position monitoring system. The system indicated that VXD3 was very stable during the whole of the 1996 run, except for known controlled movements. VXD3 was aligned globally for each period in-between these known movements using the tracks from e + e - → Z 0 → hadrons. The structure of three-jet b anti bg events has been studied using hadronic Z 0 decays from the 1993--1995 SLD data. Three-jet final states were selected and the CCD-based vertex detector was used to identify two of the jets as a b or anti b. The distributions of the gluon energy and polar angle with respect to the electron beam direction were examined and were compared with perturbative QCD predictions. It was found that the QCD Parton Shower prediction was needed to describe the data well

  10. Testing the quality of molecular structure descriptors. Vertex-degree-based topological indices

    Directory of Open Access Journals (Sweden)

    Gutman Ivan

    2013-01-01

    Full Text Available The correlation ability of 20 vertex-degree-based topological indices, occurring in the chemical literature, is tested for the case of standard heats of formation and normal boiling points of octane isomers. It is found that the correlation ability of many of these indices is either rather weak or nil. The augmented Zagreb index and the atom-bond connectivity index yield the best results. [Projekat Ministarstva nauke Republike Srbije, br. 174033

  11. A neural network for locating the primary vertex in a pixel detector

    International Nuclear Information System (INIS)

    Kantowski, R.; Marzban, C.

    1995-01-01

    Using simulated collider data for p+p→2Jets interactions in a two-barrel pixel detector, a neural network is trained to construct the coordinate of the primary vertex to a high degree of accuracy. Three other estimates of this coordinate are also considered and compared to that of the neural network. It is shown that the network can match the best of the traditional estimates. ((orig.))

  12. The BaBar silicon vertex tracker, performance and running experience

    CERN Document Server

    Re, V; Bozzi, C; Carassiti, V; Cotta-Ramusino, A; Piemontese, L; Breon, A B; Brown, D; Clark, A R; Goozen, F; Hernikl, C; Kerth, L T; Gritsan, A; Lynch, G; Perazzo, A; Roe, N A; Zizka, G; Roberts, D; Schieck, J; Brenna, E; Citterio, M; Lanni, F; Palombo, F; Ratti, L; Manfredi, P F; Angelini, C; Batignani, G; Bettarini, S; Bondioli, M; Bosi, F; Bucci, F; Calderini, G; Carpinelli, M; Ceccanti, M; Forti, F; Gagliardi, D J; Giorgi, M A; Lusiani, A; Mammini, P; Morganti, M; Morsani, F; Neri, N; Paoloni, E; Profeti, A; Rama, M; Rizzo, G; Sandrelli, F; Simi, G; Triggiani, G; Walsh, J; Burchat, Patricia R; Cheng, C; Kirkby, D; Meyer, T I; Roat, C; Bóna, M; Bianchi, F; Gamba, D; Trapani, P; Bosisio, L; Della Ricca, G; Dittongo, S; Lanceri, L; Pompili, A; Poropat, P; Rashevskaia, I; Vuagnin, G; Burke, S; Callahan, D; Campagnari, C; Dahmes, B; Hale, D; Hart, P; Kuznetsova, N; Kyre, S; Levy, S; Long, O; May, J; Mazur, M; Richman, J; Verkerke, W; Witherell, M; Beringer, J; Eisner, A M; Frey, A; Grillo, A A; Grothe, M; Johnson, R P; Kröger, W; Lockman, W S; Pulliam, T; Rowe, W; Schmitz, R E; Seiden, A; Spencer, E N; Turri, M; Walkowiak, W; Wilder, M; Wilson, M; Charles, E; Elmer, P; Nielsen, J; Orejudos, W; Scott, I; Zobernig, H

    2002-01-01

    The Silicon Vertex Tracker (SVT) of the BaBar experiment at the PEP-II asymmetric B factory is a five-layer double-sided, AC-coupled silicon microstrip detector. It represents the crucial element to precisely measure the decay position of B mesons and extract time-dependent CP asymmetries. The SVT architecture is shown and its performance is described, with emphasis on hit resolutions and efficiencies.

  13. The design and construction of the BaBar silicon vertex tracker

    CERN Document Server

    Bozzi, C; Ramusino, A C; Dittongo, S; Folegani, M; Piemontese, L; Abbott, B K; Breon, A B; Clark, A R; Dow, S; Fan, Q; Goozen, F; Hernikl, C; Karcher, A; Kerth, L T; Kipnis, I; Kluth, S; Lynch, G; Levi, M; Luft, P; Luo, L; Nyman, M A; Pedrali-Noy, M; Roe, N A; Zizka, G; Roberts, D; Barni, D; Brenna, E; Defendi, I; Forti, A C; Giugni, D; Lanni, F; Palombo, F; Vaniev, V; Leona, A; Mandelli, E; Manfredi, P F; Perazzo, A; Re, V; Angelini, C; Batignani, G; Bettarini, S; Bondioli, M; Bosi, F; Calderini, G; Carpinelli, M; Dutra, F; Forti, F; Gagliardi, D; Giorgi, M A; Lusiani, A; Mammini, P; Morganti, M; Morsani, F; Paoloni, E; Profeti, A; Rama, M; Rampino, G; Rizzo, G; Sandrelli, F; Simi, G; Triggiani, G; Tritto, S; Vitale, R; Burchat, Patricia R; Cheng, C; Kirkby, D; Meyer, T; Roat, C; Bóna, M; Bianchi, F; Daudo, F; Girolamo, B D; Gamba, D; Giraudo, G; Grosso, P; Romero, A; Smol, A; Trapani, P; Zanin, D; Bosisio, L; Della Ricca, G; Lanceri, L; Pompili, A; Poropat, P; Prest, M; Rastelli, C; Vallazza, E; Vuagnin, G; Hast, C; Potter, E P; Sharma, V; Burke, S; Callahan, D; Campagnari, C; Dahmes, B; Eppich, A; Hale, D; Hall, K; Hart, P; Kuznetsova, N; Kyre, S; Levy, S; Long, O; May, J; Richman, J; Verkerke, W; Witherell, M; Beringer, J; Eisner, A M; Frey, A; Grillo, A; Grothe, M; Johnson, R; Kröger, W; Lockman, W; Pulliam, T; Rowe, W; Schmitz, R; Seiden, A; Spencer, E; Turri, M; Wilder, M; Charles, E; Elmer, P; Nielsen, J; Orejudos, W; Scott, I; Walsh, J; Zobernig, H

    2000-01-01

    The Silicon Vertex Tracker (SVT) of the BaBar experiment at the PEP-II asymmetric B factory consists of five layers of double-sided, AC-coupled silicon strip detectors. The detectors are readout with a custom IC, capable of simultaneous acquisition, digitization and transmission of data. The SVT geometry is shown and the construction phases of its modules are described in detail, with emphasis on the bending procedures needed for the arch-modules of the outer layers.

  14. A FASTBUS flash ADC system for the Mark II vertex chamber

    International Nuclear Information System (INIS)

    Barker, L.

    1988-10-01

    This is a description of a flash ADC system built for the Mark II experiment at the Stanford Linear Accelerator Center (SLAC). This system was designed for use in the experiment's vertex chamber where signals could occur over a relatively long time, approximately 10 microseconds. This long time, coupled with fast cable amplifiers, necessitated an alternate design approach than was used with a dE/dX FASTBUS flash ADC design. 1 ref., 6 figs

  15. Approximations of quantum-graph vertex couplings by singularly scaled potentials

    Czech Academy of Sciences Publication Activity Database

    Exner, Pavel; Manko, S. S.

    2013-01-01

    Roč. 46, č. 34 (2013), s. 345202 ISSN 1751-8113 R&D Projects: GA ČR GAP203/11/0701 Institutional support: RVO:61389005 Keywords : Schrödinger operators * vertex coupling Subject RIV: BE - Theoretical Physics Impact factor: 1.687, year: 2013 http://iopscience.iop.org/1751-8121/46/34/345202/pdf/1751-8121_46_34_345202.pdf

  16. Design and Tests of the Silicon Sensors for the ZEUS Micro Vertex Detector

    OpenAIRE

    Dannheim, D.; Koetz, U.; Coldewey, C.; Fretwurst, E.; Garfagnini, A.; Klanner, R.; Martens, J.; Koffeman, E.; Tiecke, H.; Carlin, R.

    2002-01-01

    To fully exploit the HERA-II upgrade,the ZEUS experiment has installed a Micro Vertex Detector (MVD) using n-type, single-sided, silicon micro-strip sensors with capacitive charge division. The sensors have a readout pitch of 120 micrometers, with five intermediate strips (20 micrometer strip pitch). The designs of the silicon sensors and of the test structures used to verify the technological parameters, are presented. Results on the electrical measurements are discussed. A total of 1123 sen...

  17. Pion-nucleon vertex function and the Chew-Low model

    International Nuclear Information System (INIS)

    Nutt, W.T.

    1977-01-01

    We provide an interpretation of the cutoff function used in the Chew-Low theory of pion-nucleon scattering. It is shown that this function may be related to the pion-pion interaction which is not explicitly considered in the Chew-Low approach. Using a previously developed model for the pion-nucleon vertex function, we then perform a ''parameter-free'' Chew-Low calculation which predicts the P 33 resonance quite well

  18. Chemical Applications of Topology and Group Theory. 20. Eight-Vertex Polyhedra and Their Rearrangements.

    Science.gov (United States)

    1985-10-14

    Geometriae Dedicata 1975, 3, 469. *(6) Lipscomb, W. N. Science 1966, 153, 373. (7) King, R. B. J. Am. Chem. Soc. 1969, 91, 7211. * (8) Hoard, J. L...polyhedra given in Table 1 of Federico, P.J. Geometriae Dedicata 1975, 3, 469. The vertex index v7 v6v5 v4 v3 and the symmetry point group are given in

  19. A FASTBUS flash ADC system for the Mark II vertex chamber

    Energy Technology Data Exchange (ETDEWEB)

    Barker, L.

    1988-10-01

    This is a description of a flash ADC system built for the Mark II experiment at the Stanford Linear Accelerator Center (SLAC). This system was designed for use in the experiment's vertex chamber where signals could occur over a relatively long time, approximately 10 microseconds. This long time, coupled with fast cable amplifiers, necessitated an alternate design approach than was used with a dE/dX FASTBUS flash ADC design. 1 ref., 6 figs.

  20. Measurement of the triple gluon vertex from double quark tagged 4-jet events

    CERN Document Server

    Abreu, P; Adye, T; Adzic, P; Alekseev, G D; Alemany, R; Allport, P P; Almehed, S; Amaldi, Ugo; Amato, S; Andersson, P; Andreazza, A; Antilogus, P; Apel, W D; Arnoud, Y; Åsman, B; Augustin, J E; Augustinus, A; Baillon, Paul; Bambade, P; Barão, F; Barbi, M S; Barbiellini, Guido; Bardin, Dimitri Yuri; Barker, G; Baroncelli, A; Bärring, O; Bates, M J; Battaglia, Marco; Baubillier, M; Baudot, J; Becks, K H; Begalli, M; Beillière, P; Belokopytov, Yu A; Benvenuti, Alberto C; Bérat, C; Berggren, M; Bertini, D; Bertrand, D; Besançon, M; Bianchi, F; Bigi, M; Bilenky, S M; Billoir, P; Bizouard, M A; Bloch, D; Blume, M; Bonesini, M; Bonivento, W; Boonekamp, M; Booth, P S L; Borgland, A W; Borisov, G; Bosio, C; Botner, O; Boudinov, E; Bouquet, B; Bourdarios, C; Bowcock, T J V; Bozzo, M; Branchini, P; Brand, K D; Brenke, T; Brenner, R A; Brown, R C A; Brückman, P; Brunet, J M; Bugge, L; Buran, T; Burgsmüller, T; Buschmann, P; Cabrera, S; Caccia, M; Calvi, M; Camacho-Rozas, A J; Camporesi, T; Canale, V; Canepa, M; Carena, F; Carroll, L; Caso, Carlo; Castillo-Gimenez, M V; Cattai, A; Cavallo, F R; Chabaud, V; Charpentier, P; Chaussard, L; Checchia, P; Chelkov, G A; Chen, M; Chierici, R; Chliapnikov, P V; Chochula, P; Chorowicz, V; Chudoba, J; Cindro, V; Collins, P; Colomer, M; Contri, R; Cortina, E; Cosme, G; Cossutti, F; Cowell, J H; Crawley, H B; Crennell, D J; Crosetti, G; Cuevas-Maestro, J; Czellar, S; Dahm, J; D'Almagne, B; Damgaard, G; Dauncey, P D; Davenport, Martyn; Da Silva, W; Deghorain, A; Della Ricca, G; Delpierre, P A; Demaria, N; De Angelis, A; de Boer, Wim; De Brabandere, S; De Clercq, C; La Vaissière, C de; De Lotto, B; De Min, A; De Paula, L S; Dijkstra, H; Di Ciaccio, Lucia; Di Diodato, A; Djannati, A; Dolbeau, J; Doroba, K; Dracos, M; Drees, J; Drees, K A; Dris, M; Durand, J D; Edsall, D M; Ehret, R; Eigen, G; Ekelöf, T J C; Ekspong, Gösta; Elsing, M; Engel, J P; Erzen, B; Espirito-Santo, M C; Falk, E; Fanourakis, G K; Fassouliotis, D; Feindt, Michael; Fenyuk, A; Ferrari, P; Ferrer, A; Fichet, S; Filippas-Tassos, A; Firestone, A; Fischer, P A; Föth, H; Fokitis, E; Fontanelli, F; Formenti, F; Franek, B J; Frodesen, A G; Frühwirth, R; Fulda-Quenzer, F; Fuster, J A; Galloni, A; Gamba, D; Gandelman, M; García, C; García, J; Gaspar, C; Gasparini, U; Gavillet, P; Gazis, E N; Gelé, D; Gerber, J P; Geryukov, L; Gokieli, R; Golob, B; Gonçalves, P; Gopal, Gian P; Gorn, L; Górski, M; Guz, Yu; Gracco, Valerio; Graziani, E; Green, C; Grefrath, A; Gris, P; Grosdidier, G; Grzelak, K; Günther, M; Guy, J; Hahn, F; Hahn, S; Hajduk, Z; Hallgren, A; Hamacher, K; Harris, F J; Hedberg, V; Henriques, R P; Hernández, J J; Herquet, P; Herr, H; Hessing, T L; Heuser, J M; Higón, E; Holmgren, S O; Holt, P J; Holthuizen, D J; Hoorelbeke, S; Houlden, M A; Hrubec, Josef; Huet, K; Hultqvist, K; Jackson, J N; Jacobsson, R; Jalocha, P; Janik, R; Jarlskog, C; Jarlskog, G; Jarry, P; Jean-Marie, B; Johansson, E K; Jönsson, L B; Jönsson, P E; Joram, Christian; Juillot, P; Kaiser, M; Kapusta, F; Karafasoulis, K; Karvelas, E; Katsanevas, S; Katsoufis, E C; Keränen, R; Khokhlov, Yu A; Khomenko, B A; Khovanskii, N N; King, B J; Kjaer, N J; Klapp, O; Klein, H; Kluit, P M; Knoblauch, D; Kokkinias, P; Konoplyannikov, A K; Koratzinos, M; Korcyl, K; Kostyukhin, V; Kourkoumelis, C; Kuznetsov, O; Kreuter, C; Kronkvist, I J; Krumshtein, Z; Krupinski, W; Kubinec, P; Kucewicz, W; Kurvinen, K L; Lacasta, C; Laktineh, I; Lamsa, J; Lanceri, L; Lane, D W; Langefeld, P; Laugier, J P; Lauhakangas, R; Leder, Gerhard; Ledroit, F; Lefébure, V; Legan, C K; Leisos, A; Leitner, R; Lemonne, J; Lenzen, Georg; Lepeltier, V; Lesiak, T; Lethuillier, M; Libby, J; Liko, D; Lipniacka, A; Lippi, I; Lörstad, B; Loken, J G; López, J M; Loukas, D; Lutz, P; Lyons, L; MacNaughton, J N; Maehlum, G; Mahon, J R; Maio, A; Malmgren, T G M; Malychev, V; Mandl, F; Marco, J; Marco, R P; Maréchal, B; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Martínez-Rivero, C; Martínez-Vidal, F; Martí i García, S; Masik, J; Matorras, F; Matteuzzi, C; Matthiae, Giorgio; Mazzucato, M; McCubbin, M L; McKay, R; McNulty, R; McPherson, G; Medbo, J; Meroni, C; Meyer, S; Meyer, W T; Myagkov, A; Michelotto, M; Migliore, E; Mirabito, L; Mitaroff, Winfried A; Mjörnmark, U; Moa, T; Møller, R; Mönig, K; Monge, M R; Morettini, P; Müller, H; Münich, K; Mulders, M; Mundim, L M; Murray, W J; Muryn, B; Myatt, Gerald; Myklebust, T; Naraghi, F; Navarria, Francesco Luigi; Navas, S; Nawrocki, K; Negri, P; Neumann, W; Neumeister, N; Nicolaidou, R; Nielsen, B S; Nieuwenhuizen, M; Nikolaenko, V; Nikolenko, M; Niss, P; Nomerotski, A; Normand, Ainsley; Nygren, A; Oberschulte-Beckmann, W; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, Risto; Orazi, G; Ortuno, S; Österberg, K; Ouraou, A; Paganini, P; Paganoni, M; Paiano, S; Pain, R; Palka, H; Papadopoulou, T D; Papageorgiou, K; Pape, L; Parkes, C; Parodi, F; Parzefall, U; Passeri, A; Pegoraro, M; Peralta, L; Pernegger, H; Pernicka, Manfred; Perrotta, A; Petridou, C; Petrolini, A; Phillips, H T; Piana, G; Pierre, F; Piotto, E; Podobnik, T; Podobrin, O; Pol, M E; Polok, G; Poropat, P; Pozdnyakov, V; Privitera, P; Pukhaeva, N; Pullia, Antonio; Radojicic, D; Ragazzi, S; Rahmani, H; Rames, J; Ratoff, P N; Read, A L; Reale, M; Rebecchi, P; Redaelli, N G; Regler, Meinhard; Reid, D; Reinhardt, R; Renton, P B; Resvanis, L K; Richard, F; Rídky, J; Rinaudo, G; Røhne, O M; Romero, A; Ronchese, P; Roos, L; Rosenberg, E I; Rosinsky, P; Roudeau, Patrick; Rovelli, T; Ruhlmann-Kleider, V; Ruiz, A; Rybicki, K; Saarikko, H; Sacquin, Yu; Sadovskii, A; Sajot, G; Salt, J; Sannino, M; Schneider, H; Schwickerath, U; Schyns, M A E; Sciolla, G; Scuri, F; Seager, P; Sedykh, Yu; Segar, A M; Seitz, A; Sekulin, R L; Serbelloni, L; Shellard, R C; Sheridan, A; Siegrist, P; Silvestre, R; Simonetto, F; Sissakian, A N; Skaali, T B; Smadja, G; Smirnov, N; Smirnova, O G; Smith, G R; Sokolov, A; Solovyanov, O; Sosnowski, R; Souza-Santos, D; Spassoff, Tz; Spiriti, E; Sponholz, P; Squarcia, S; Stampfer, D; Stanescu, C; Stanic, S; Stapnes, Steinar; Stavitski, I; Stevenson, K; Stocchi, A; Strauss, J; Strub, R; Stugu, B; Szczekowski, M; Szeptycka, M; Tabarelli de Fatis, T; Tavernet, J P; Chernyaev, E; Tegenfeldt, F; Terranova, F; Thomas, J; Tilquin, A; Timmermans, J; Tkatchev, L G; Todorov, T; Todorova, S; Toet, D Z; Tomaradze, A G; Tomé, B; Tonazzo, A; Tortora, L; Tranströmer, G; Treille, D; Tristram, G; Trombini, A; Troncon, C; Tsirou, A L; Turluer, M L; Tyapkin, I A; Tyndel, M; Tzamarias, S; Überschär, B; Ullaland, O; Uvarov, V; Valenti, G; Vallazza, E; van Apeldoorn, G W; van Dam, P; Van Eldik, J; Van Lysebetten, A; Vassilopoulos, N; Vegni, G; Ventura, L; Venus, W A; Verbeure, F; Verlato, M; Vertogradov, L S; Vilanova, D; Vincent, P; Vitale, L; Vodopyanov, A S; Vrba, V; Wahlen, H; Walck, C; Weiser, C; Wetherell, Alan M; Wicke, D; Wickens, J H; Wielers, M; Wilkinson, G R; Williams, W S C; Winter, M; Witek, M; Wlodek, T; Yi, J; Yip, K; Yushchenko, O P; Zach, F; Zaitsev, A; Zalewska-Bak, A; Zalewski, Piotr; Zavrtanik, D; Zevgolatakos, E; Zimin, N I; Zucchelli, G C; Zumerle, G

    1997-01-01

    The 4-jet events collected by the DELPHI experiment at LEP1 in 1992, 1993 and 1994 are analysed to determine the contribution of the triple-gluon vertex. Two of the four jets are tagged as jets from $b$- or $c$-quarks using lifetime and lepton transverse momentum information. The 4-jet contributions from double-gluon bremsstrahlung, the triple-gluon vertex, and secondary quark-antiquark pair production then yield significantly different two-dimensional distributions in the generalized Nachtmann Reiter angle %$\\Theta^{*}_{NR}$ versus the opening angle of the two secondary jets. These distributions are used to fit $C_A/C_F$, the ratio of the coupling strength of the triple-gluon vertex to that of gluon bremsstrahlung, and $N_C/N_A$, the ratio of the number of quark colours to the number of gluons, giving \\begin{center} $C_A/C_F=2.51 \\pm 0.28$ ~and~ $N_C/N_A=0.38 \\pm 0.10$ \\end{center} in agreement with the values expected from QCD: \\begin{center} $C_A/C_F = 9/4 = 2.25$ ~and~ $N_C/N_A = 3/8 = 0.375$. \\end{center...

  1. Graphs with vertex-coloring and detectable 2-edge-weighting

    Directory of Open Access Journals (Sweden)

    N. Paramaguru

    2016-08-01

    Full Text Available For a connected graph G of order |V(G|≥3 and a k-edge-weighting c:E(G→{1,2,…,k} of the edges of G, the code, codec(v, of a vertex v of G is the ordered k-tuple (ℓ1,ℓ2,…,ℓk, where ℓi is the number of edges incident with v that are weighted i. (i The k-edge-weighting c is detectable if every two adjacent vertices of G have distinct codes. The minimum positive integer k for which G has a detectable k-edge-weighting is the detectable chromatic number det(G of G. (ii The k-edge-weighting c is a vertex-coloring if every two adjacent vertices u,v of G with codes codec(u=(ℓ1,ℓ2,…,ℓk and codec(v=(ℓ1′,ℓ2′,…,ℓk′ have 1ℓ1+2ℓ2+⋯+kℓk≠1ℓ1′+2ℓ2′+⋯+kℓk′. The minimum positive integer k for which G has a vertex-coloring k-edge-weighting is denoted by μ(G. In this paper, we have enlarged the known families of graphs with det(G=μ(G=2.

  2. TRACKING AND VERTEXING WITH THE ATLAS INNER DETECTOR IN THE LHC RUN2 AND BEYOND

    CERN Document Server

    Choi, Kyungeon; The ATLAS collaboration

    2017-01-01

    Run-2 of the LHC has provided new challenges to track and vertex reconstruction with higher centre-of-mass energies and luminosity leading to increasingly high-multiplicity environments, boosted, and highly-collimated physics objects. To achieve this goal, ATLAS is equipped with the Inner Detector tracking system built using different technologies, silicon planar sensors (pixel and micro-strip) and gaseous drift- tubes, all embedded in a 2T solenoidal magnetic field. In addition, the Insertable B-layer (IBL) is a fourth pixel layer, which was inserted at the centre of ATLAS during the first long shutdown of the LHC. An overview of the use of each of these subdetectors in track and vertex reconstruction, as well as the algorithmic approaches taken to the specific tasks of pattern recognition and track fitting, is given. The performance of the Inner Detector tracking and vertexing will be summarised. These include a factor of three reduction in the reconstruction time, optimisation for the expected conditions, ...

  3. Tracking and Vertexing with the ATLAS Inner Detector in the LHC Run2 and Beyond

    CERN Document Server

    Swift, Stewart Patrick; The ATLAS collaboration

    2017-01-01

    Run-2 of the LHC has provided new challenges to track and vertex reconstruction with higher centre-of-mass energies and luminosity leading to increasingly high-multiplicity environments, boosted, and highly-collimated physics objects. To achieve this goal, ATLAS is equipped with the Inner Detector tracking system built using different technologies, silicon planar sensors (pixel and micro-strip) and gaseous drift- tubes, all embedded in a 2T solenoidal magnetic field. In addition, the Insertable B-layer (IBL) is a fourth pixel layer, which was inserted at the centre of ATLAS during the first long shutdown of the LHC. An overview of the use of each of these subdetectors in track and vertex reconstruction, as well as the algorithmic approaches taken to the specific tasks of pattern recognition and track fitting, is given. The performance of the Inner Detector tracking and vertexing will be summarised. These include a factor of three reduction in the reconstruction time, optimisation for the expected conditions, ...

  4. Exclusive many-particle diffusion in disordered media and correlation functions for random vertex models

    International Nuclear Information System (INIS)

    Schuetz, G.; Sandow, S.

    1993-05-01

    We consider systems of particles hopping stochastically on d-dimensional lattices with space-dependent probabilities. We map the master equation in a Fock space where the dynamics are given by a quantum Hamiltonian (continuous time) or a transfer matrix resp. (discrete time). We show that under certain conditions the time-dependent two-point density correlation function in N-particle steady state can be computed from the probability distribution of a single particle moving in the same environment. Focussing on exclusion models where the lattice site can be occupied by at most one particle we discuss as an example for such a stochastic process a generalized Heisenberg antiferromagnet where the strength of the spin-spin coupling in space-dependent. In discrete time one obtains for one dimensional systems the diagonal-to-diagonal transfer matrix of the two dimensional six vertex model with space dependent vertex weights. For a random distribution of the vertex weights one obtains a version of the random barrier model describing diffusion of particles in disordered media. We derive exact expressions for the average two-point density correlation function in the presence of weak, correlated disorder. (authors)

  5. Asymmetric Game: A Silver Bullet to Weighted Vertex Cover of Networks.

    Science.gov (United States)

    Tang, Changbing; Li, Ang; Li, Xiang

    2017-10-16

    Weighted vertex cover (WVC), a generalized type of vertex cover, is one of the most important combinatorial optimization problems. In this paper, we provide a novel solution to the WVC problem from the view of network engineering. We model the WVC problem as an asymmetric game on weighted networks, where each vertex is treated as an intelligent rational agent rather than an inanimate one. Under the framework of asymmetric game, we find that strict Nash equilibriums of the asymmetric game are the intermediate states between the WVC states and the minimum WVC (MWVC) states. Besides, we propose best response algorithms with memory and feedback to solve the WVC problem, and find that a better approximate solution to the MWVC can be obtained under the feedback-based best response algorithm. Numerical illustrations verify the performance of the proposed game solution on weighted networks. Our findings pave a new way to solve the WVC problem from the perspective of asymmetric game, which opens a bottom-up avenue to address the combinatorial optimization problems.

  6. Towards an ab-initio treatment of nonlocal electronic correlations with dynamical vertex approximation

    Science.gov (United States)

    Galler, Anna; Gunacker, Patrik; Tomczak, Jan; Thunström, Patrik; Held, Karsten

    Recently, approaches such as the dynamical vertex approximation (D ΓA) or the dual-fermion method have been developed. These diagrammatic approaches are going beyond dynamical mean field theory (DMFT) by including nonlocal electronic correlations on all length scales as well as the local DMFT correlations. Here we present our efforts to extend the D ΓA methodology to ab-initio materials calculations (ab-initio D ΓA). Our approach is a unifying framework which includes both GW and DMFT-type of diagrams, but also important nonlocal correlations beyond, e.g. nonlocal spin fluctuations. In our multi-band implementation we are using a worm sampling technique within continuous-time quantum Monte Carlo in the hybridization expansion to obtain the DMFT vertex, from which we construct the reducible vertex function using the two particle-hole ladders. As a first application we show results for transition metal oxides. Support by the ERC project AbinitioDGA (306447) is acknowledged.

  7. [The influence of polymerization time on physicochemical properties of the acrylic resin Vertex RS].

    Science.gov (United States)

    Fraczak, Bogumiła; Sobolewska, Ewa; Ey-Chmielewska, Halina; Skowronek, Maria; Błazewicz, Stanisław

    2009-01-01

    A good denture can only be produced through proper actions during the clinical and laboratory stages of the production process. The aim of this study was to determine if a change in polymerization time affects the physicochemical properties of polymethacrylate material used for dentures. We examined the acrylic resin Vertex R.S. polymerized for 15, 25, 40, or 60 minutes. Palapress Vario was taken as reference material. Static bending, microhardness, surface wettability, and susceptibility to abrasion were determined. The microhardness test showed that most of the samples had similar Vickers hardness (VS) values, except for the sample polymerized for 25 min. which demonstrated a significantly higher value. Grindability was affected by a change in polymerization time. Mass loss was greatest for samples polymerized for 15, 25, and 60 min. and smallest for Vertex 40 and Palapress Vario. We also observed differences in the wetting angle. Vertex 40 and 60 had a relatively low wetting angle signifying that longer polymerization time results in lower hydrophobicity of the material. The present study has demonstrated that polymerization time has a significant effect on the hardness and some mechanical properties of the acrylic resin.

  8. Studies of radiation hardness of MOS devices for application in a linear collider vertex detector

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Qingyu

    2008-10-17

    The proposed International Linear Collider (ILC) together with the Large Hadron Collider (LHC) at CERN serve as a combined tool to explore the mysteries of the universe: the former is a precision machine and the latter can be considered as a finding machine. The key component of the ILC is the vertex detector that should be placed as close as possible to the Interaction Point (IP) and has better radiation tolerance against the dominant electron-positron pair production background from beam-beam interactions. A new generation of MOS-type Depleted-Field-Effect Transistor (MOSDEPFET) active pixel detectors has been proposed and developed by Semiconductor Labor Munich for Physics and for extraterrestrial Physics in order to meet the requirements of the vertex detector at the ILC. Since all MOS devices are susceptible to ionizing radiation, the main topic is focused on the radiation hardness of detectors, by which a series of physical processes are analyzed: e.g. surface damage due to ionizing radiation as well as damage mechanisms and their associated radiation effects. As a consequence, the main part of this thesis consists of a large number of irradiation experiments and the corresponding discussions. Finally, radiation hardness of the detectors should be improved through a set of concluded experiences that are based on a series of analysis of the characteristic parameters using different measurement techniques. The feasibility of the MOSDEPFET-based vertex detector is, therefore, predicted at ILC. (orig.)

  9. An asynchronous data-driven readout prototype for CEPC vertex detector

    Science.gov (United States)

    Yang, Ping; Sun, Xiangming; Huang, Guangming; Xiao, Le; Gao, Chaosong; Huang, Xing; Zhou, Wei; Ren, Weiping; Li, Yashu; Liu, Jianchao; You, Bihui; Zhang, Li

    2017-12-01

    The Circular Electron Positron Collider (CEPC) is proposed as a Higgs boson and/or Z boson factory for high-precision measurements on the Higgs boson. The precision of secondary vertex impact parameter plays an important role in such measurements which typically rely on flavor-tagging. Thus silicon CMOS Pixel Sensors (CPS) are the most promising technology candidate for a CEPC vertex detector, which can most likely feature a high position resolution, a low power consumption and a fast readout simultaneously. For the R&D of the CEPC vertex detector, we have developed a prototype MIC4 in the Towerjazz 180 nm CMOS Image Sensor (CIS) process. We have proposed and implemented a new architecture of asynchronous zero-suppression data-driven readout inside the matrix combined with a binary front-end inside the pixel. The matrix contains 128 rows and 64 columns with a small pixel pitch of 25 μm. The readout architecture has implemented the traditional OR-gate chain inside a super pixel combined with a priority arbiter tree between the super pixels, only reading out relevant pixels. The MIC4 architecture will be introduced in more detail in this paper. It will be taped out in May and will be characterized when the chip comes back.

  10. Combining Vertex-centric Graph Processing with SPARQL for Large-scale RDF Data Analytics

    KAUST Repository

    Abdelaziz, Ibrahim

    2017-06-27

    Modern applications, such as drug repositioning, require sophisticated analytics on RDF graphs that combine structural queries with generic graph computations. Existing systems support either declarative SPARQL queries, or generic graph processing, but not both. We bridge the gap by introducing Spartex, a versatile framework for complex RDF analytics. Spartex extends SPARQL to support programs that combine seamlessly generic graph algorithms (e.g., PageRank, Shortest Paths, etc.) with SPARQL queries. Spartex builds on existing vertex-centric graph processing frameworks, such as Graphlab or Pregel. It implements a generic SPARQL operator as a vertex-centric program that interprets SPARQL queries and executes them efficiently using a built-in optimizer. In addition, any graph algorithm implemented in the underlying vertex-centric framework, can be executed in Spartex. We present various scenarios where our framework simplifies significantly the implementation of complex RDF data analytics programs. We demonstrate that Spartex scales to datasets with billions of edges, and show that our core SPARQL engine is at least as fast as the state-of-the-art specialized RDF engines. For complex analytical tasks that combine generic graph processing with SPARQL, Spartex is at least an order of magnitude faster than existing alternatives.

  11. Exploratory study of a novel low occupancy vertex detector architecture based on high precision timing for high luminosity particle colliders

    Energy Technology Data Exchange (ETDEWEB)

    Orel, Peter, E-mail: porel@hawaii.edu; Varner, Gary S.; Niknejadi, Pardis

    2017-06-11

    Vertex detectors provide space–time coordinates for the traversing charged particle decay products closest to the interaction point. Resolving these increasingly intense particle fluences at high luminosity particle colliders, such as SuperKEKB, is an ever growing challenge. This results in a non-negligible occupancy of the vertex detector using existing low material budget techniques. Consequently, new approaches are being studied that meet the vertexing requirements while lowering the occupancy. In this paper, we introduce a novel vertex detector architecture. Its design relies on an asynchronous digital pixel matrix in combination with a readout based on high precision time-of-flight measurement. Denoted the Timing Vertex Detector (TVD), it consists of a binary pixel array, a transmission line for signal collection, and a readout ASIC. The TVD aims to have a spatial resolution comparable to the existing Belle2 vertex detector. At the same time it offers a reduced occupancy by a factor of ten while decreasing the channel count by almost three orders of magnitude. Consequently, reducing the event size from about 1 MB/event to about 5.9 kB/event.

  12. Potential landscape and flux field theory for turbulence and nonequilibrium fluid systems

    Science.gov (United States)

    Wu, Wei; Zhang, Feng; Wang, Jin

    2018-02-01

    Turbulence is a paradigm for far-from-equilibrium systems without time reversal symmetry. To capture the nonequilibrium irreversible nature of turbulence and investigate its implications, we develop a potential landscape and flux field theory for turbulent flow and more general nonequilibrium fluid systems governed by stochastic Navier-Stokes equations. We find that equilibrium fluid systems with time reversibility are characterized by a detailed balance constraint that quantifies the detailed balance condition. In nonequilibrium fluid systems with nonequilibrium steady states, detailed balance breaking leads directly to a pair of interconnected consequences, namely, the non-Gaussian potential landscape and the irreversible probability flux, forming a 'nonequilibrium trinity'. The nonequilibrium trinity characterizes the nonequilibrium irreversible essence of fluid systems with intrinsic time irreversibility and is manifested in various aspects of these systems. The nonequilibrium stochastic dynamics of fluid systems including turbulence with detailed balance breaking is shown to be driven by both the non-Gaussian potential landscape gradient and the irreversible probability flux, together with the reversible convective force and the stochastic stirring force. We reveal an underlying connection of the energy flux essential for turbulence energy cascade to the irreversible probability flux and the non-Gaussian potential landscape generated by detailed balance breaking. Using the energy flux as a center of connection, we demonstrate that the four-fifths law in fully developed turbulence is a consequence and reflection of the nonequilibrium trinity. We also show how the nonequilibrium trinity can affect the scaling laws in turbulence.

  13. On Equivalence of Nonequilibrium Thermodynamic and Statistical Entropies

    Directory of Open Access Journals (Sweden)

    Purushottam D. Gujrati

    2015-02-01

    Full Text Available We review the concept of nonequilibrium thermodynamic entropy and observables and internal variables as state variables, introduced recently by us, and provide a simple first principle derivation of additive statistical entropy, applicable to all nonequilibrium states by treating thermodynamics as an experimental science. We establish their numerical equivalence in several cases, which includes the most important case when the thermodynamic entropy is a state function. We discuss various interesting aspects of the two entropies and show that the number of microstates in the Boltzmann entropy includes all possible microstates of non-zero probabilities even if the system is trapped in a disjoint component of the microstate space. We show that negative thermodynamic entropy can appear from nonnegative statistical entropy.

  14. Phase transitions, scaling and renormalisation in nonequilibrium systems

    CERN Document Server

    Hanney, T E

    2002-01-01

    critical fixed point. Extensions to include disorder, to higher dimensions, and to other models are all possible using the method. Using the mapping between the Master equation and the Schroedinger equation in imaginary time, this scaling procedure is rephrased as a new blocking for quantum-spin systems. Existing methods of real space renormalisation for quantum-spin systems are applied to a variety of previously unconsidered exclusion models. In particular, it is shown how such techniques can be applied to models whose dynamics conserve particle number. Finally, by applying a Trotter decomposition to the quantum-spin Hamiltonian, it is shown how a nonequilibrium exclusion model can be written in terms of a classical Hamiltonian for Ising spin variables in one higher dimension. This mapping admits the possibility rescaling time and length scales separately, and with reference to a specific update mechanism. Nonequilibrium phase transitions and critical phenomena in simple lattice-based interacting particle mo...

  15. Density-functional method for nonequilibrium electron transport

    DEFF Research Database (Denmark)

    Brandbyge, Mads; Mozos, J.L.; Ordejon, P.

    2002-01-01

    We describe an ab initio method for calculating the electronic structure, electronic transport, and forces acting on the atoms, for atomic scale systems connected to semi-infinite electrodes and with an applied voltage bias. Our method is based on the density-functional theory (DFT) as implemented...... in the well tested SIESTA approach (which uses nonlocal norm-conserving pseudopotentials to describe the effect of the core electrons, and linear combination of finite-range numerical atomic orbitals to describe the valence states). We fully deal with the atomistic structure of the whole system, treating both...... the contact and the electrodes on the same footing. The effect of the finite bias (including self-consistency and the solution of the electrostatic problem) is taken into account using nonequilibrium Green's functions. We relate the nonequilibrium Green's function expressions to the more transparent scheme...

  16. Extreme quantum nonequilibrium, nodes, vorticity, drift and relaxation retarding states

    Science.gov (United States)

    Underwood, Nicolas G.

    2018-02-01

    Consideration is given to the behaviour of de Broglie trajectories that are separated from the bulk of the Born distribution with a view to describing the quantum relaxation properties of more ‘extreme’ forms of quantum nonequilibrium. For the 2D isotropic harmonic oscillator, through the construction of what is termed the ‘drift field’, a description is given of a general mechanism that causes the relaxation of ‘extreme’ quantum nonequilibrium. Quantum states are found which do not feature this mechanism, so that relaxation may be severely delayed or possibly may not take place at all. A method by which these states may be identified, classified and calculated is given in terms of the properties of the nodes of the state. Properties of the nodes that enable this classification are described for the first time.

  17. Non-equilibrium plasma reactor for natrual gas processing

    International Nuclear Information System (INIS)

    Shair, F.H.; Ravimohan, A.L.

    1974-01-01

    A non-equilibrium plasma reactor for natural gas processing into ethane and ethylene comprising means of producing a non-equilibrium chemical plasma wherein selective conversion of the methane in natural gas to desired products of ethane and ethylene at a pre-determined ethane/ethylene ratio in the chemical process may be intimately controlled and optimized at a high electrical power efficiency rate by mixing with a recycling gas inert to the chemical process such as argon, helium, or hydrogen, reducing the residence time of the methane in the chemical plasma, selecting the gas pressure in the chemical plasma from a wide range of pressures, and utilizing pulsed electrical discharge producing the chemical plasma. (author)

  18. Construction of a Non-Equilibrium Thermal Boundary Layer Facility

    Science.gov (United States)

    Biles, Drummond; Ebadi, Alireza; Ma, Allen; White, Christopher

    2015-11-01

    A thermally conductive, electrically heated wall-plate forming the bottom wall of a wind tunnel has been constructed and validation tests have been performed. The wall-plate is a sectioned wall design, where each section is independently heated and controlled. Each section consists of an aluminum 6061 plate, an array of resistive heaters affixed to the bottom of the aluminum plate, and a calcium silicate holder used for thermal isolation. Embedded thermocouples in the aluminum plates are used to monitor the wall temperature and for feedback control of wall heating. The wall-plate is used to investigate thermal transport in both equilibrium and non-equilibrium boundary layers. The non-equilibrium boundary layer flow investigated is oscillatory flow produced by a rotor-stator mechanism placed downstream of the test section of the wind tunnel.

  19. Nonequilibrium 1/f γ noise in conducting films and contacts

    International Nuclear Information System (INIS)

    Zhigal'skii, Gennadii P

    2003-01-01

    Work on nonequilibrium flicker-noise (1/f γ noise or NEFN) in conducting films of various materials and in thin-film contacts is reviewed. Experimental methods for studying nonequilibrium flicker fluctuations by separating NEFN from the total noise are suggested. Published results on NEFN in metal and alloy films, Ni/Cr-film and Ta x N y -film resistors, and contacts are systematized. It is shown that various kinds of NEFN occur in conducting films. Depending on test conditions, external influences, and the film microstructure, both stationary and non-stationary NEFNs are observed. The use of 1/f γ noise measurements for nondestructively controlling the quality of thin-film conductors is substantiated. For most of the passive IC components (thin-film conductors, resistive layers, contacts), NEFN makes a much more informative quality indicator than equilibrium flicker-noise. (reviews of topical problems)

  20. 14th International Conference on Nonequilibrium Carrier Dynamics in Semiconductors

    CERN Document Server

    Saraniti, M; Nonequilibrium Carrier Dynamics in Semiconductors

    2006-01-01

    International experts gather every two years at this established conference to discuss recent developments in theory and experiment in non-equilibrium transport phenomena. These developments have been the driving force behind the spectacular advances in semiconductor physics and devices over the last few decades. Originally known as "Hot Carriers in Semiconductors," the 14th conference in the series covered a wide spectrum of traditional topics dealing with non-equilibrium phenomena, ranging from quantum transport to optical phenomena in mesoscopic and nano-scale structures. Particular attention was given this time to emerging areas of this rapidly evolving field, with many sessions covering terahertz devices, high field transport in nitride semiconductors, spintronics, molecular electronics, and bioelectronics applications.

  1. Nonequilibrium Thermodynamics of Ion Flux through Membrane Channels

    Directory of Open Access Journals (Sweden)

    Chi-Pan Hsieh

    2017-01-01

    Full Text Available Ion flux through membrane channels is passively driven by the electrochemical potential differences across the cell membrane. Nonequilibrium thermodynamics has been successful in explaining transport mechanisms, including the ion transport phenomenon. However, physiologists may not be familiar with biophysical concepts based on the view of entropy production. In this paper, I have reviewed the physical meanings and connections between nonequilibrium thermodynamics and the expressions commonly used in describing ion fluxes in membrane physiology. The fluctuation theorem can be applied to interpret the flux ratio in the small molecular systems. The multi-ion single-file feature of the ion channel facilitates the utilization of the natural tendency of electrochemical driving force to couple specific biophysical processes and biochemical reactions on the membrane.

  2. Investigation of Non-Equilibrium Radiation for Earth Entry

    Science.gov (United States)

    Brandis, A. M.; Johnston, C. O.; Cruden, B. A.

    2016-01-01

    For Earth re-entry at velocities between 8 and 11.5 km/s, the accuracy of NASA's computational uid dynamic and radiative simulations of non-equilibrium shock layer radiation is assessed through comparisons with measurements. These measurements were obtained in the NASA Ames Research Center's Electric Arc Shock Tube (EAST) facility. The experiments were aimed at measuring the spatially and spectrally resolved radiance at relevant entry conditions for both an approximate Earth atmosphere (79% N2 : 21% O2 by mole) as well as a more accurate composition featuring the trace species Ar and CO2 (78.08% N2 : 20.95% O2 : 0.04% CO2 : 0.93% Ar by mole). The experiments were configured to target a wide range of conditions, of which shots from 8 to 11.5 km/s at 0.2 Torr (26.7 Pa) are examined in this paper. The non-equilibrium component was chosen to be the focus of this study as it can account for a significant percentage of the emitted radiation for Earth re-entry, and more importantly, non-equilibrium has traditionally been assigned a large uncertainty for vehicle design. The main goals of this study are to present the shock tube data in the form of a non-equilibrium metric, evaluate the level of agreement between the experiment and simulations, identify key discrepancies and to examine critical aspects of modeling non-equilibrium radiating flows. Radiance pro les integrated over discreet wavelength regions, ranging from the Vacuum Ultra Violet (VUV) through to the Near Infra-Red (NIR), were compared in order to maximize both the spectral coverage and the number of experiments that could be used in the analysis. A previously defined non-equilibrium metric has been used to allow comparisons with several shots and reveal trends in the data. Overall, LAURA/HARA is shown to under-predict EAST by as much as 40% and over-predict by as much as 12% depending on the shock speed. DPLR/NEQAIR is shown to under-predict EAST by as much as 50% and over-predict by as much as 20% depending

  3. Non-equilibrium statistical physics with application to disordered systems

    CERN Document Server

    Cáceres, Manuel Osvaldo

    2017-01-01

    This textbook is the result of the enhancement of several courses on non-equilibrium statistics, stochastic processes, stochastic differential equations, anomalous diffusion and disorder. The target audience includes students of physics, mathematics, biology, chemistry, and engineering at undergraduate and graduate level with a grasp of the basic elements of mathematics and physics of the fourth year of a typical undergraduate course. The little-known physical and mathematical concepts are described in sections and specific exercises throughout the text, as well as in appendices. Physical-mathematical motivation is the main driving force for the development of this text. It presents the academic topics of probability theory and stochastic processes as well as new educational aspects in the presentation of non-equilibrium statistical theory and stochastic differential equations.. In particular it discusses the problem of irreversibility in that context and the dynamics of Fokker-Planck. An introduction on fluc...

  4. Supersymmetric electroweak baryogenesis, nonequilibrium field theory and quantum Boltzmann equations

    CERN Document Server

    Riotto, Antonio

    1998-01-01

    The closed time-path (CPT) formalism is a powerful Green's function formulation to describe nonequilibrium phenomena in field theory and it leads to a complete nonequilibrium quantum kinetic theory. In this paper we make use of the CPT formalism to write down a set of quantum Boltzmann equations describing the local number density asymmetries of the particles involved in supersymmetric electroweak baryogenesis. These diffusion equations automatically and self-consistently incorporate the CP-violating sources which fuel baryogenesis when transport properties allow the CP-violating charges to diffuse in front of the bubble wall separating the broken from the unbroken phase at the electroweak phase transition. This is a significant improvement with respect to recent approaches where the CP-violating sources are inserted by hand into the diffusion equations. Furthermore, the CP-violating sources and the particle number changing interactions manifest ``memory'' effects which are typical of the quantum transp ort t...

  5. Analysis of Atomic Electronic Excitation in Nonequilibrium Air Plasmas

    International Nuclear Information System (INIS)

    He Xin; Jia Hong-Hui; Yin Hong-Wei; Zhang Hai-Liang; Chang Sheng-Li; Yang Jun-Cai; Dang Wei-Hua

    2014-01-01

    Electronic excitation of atoms is studied in nonequilibrium air plasmas with the electronic temperature between 8000 K and 20000 K. By using the modified Saha—Boltzmann equation, our simplified method takes into account significant radiative processes and strong self-absorption of the vacuum ultraviolet lines. Calculations are carried out at three trajectory points of the Fire II flight experiment. Good agreement with the detailed collisional-radiative model is obtained, and the performance of this method in applications to highly nonequilibrium conditions is better than Park's quasi-steady-state model and Spradian-9.0. A short discussion on the influence of optical thickness of the vacuum ultraviolet radiation is also given. It costs about 2.9 ms on the average to solve one cell of the shock layer on a low cost computer, which shows that the present method is fast and efficient. (physics of gases, plasmas, and electric discharges)

  6. Optimal control of transitions between nonequilibrium steady states.

    Directory of Open Access Journals (Sweden)

    Patrick R Zulkowski

    Full Text Available Biological systems fundamentally exist out of equilibrium in order to preserve organized structures and processes. Many changing cellular conditions can be represented as transitions between nonequilibrium steady states, and organisms have an interest in optimizing such transitions. Using the Hatano-Sasa Y-value, we extend a recently developed geometrical framework for determining optimal protocols so that it can be applied to systems driven from nonequilibrium steady states. We calculate and numerically verify optimal protocols for a colloidal particle dragged through solution by a translating optical trap with two controllable parameters. We offer experimental predictions, specifically that optimal protocols are significantly less costly than naive ones. Optimal protocols similar to these may ultimately point to design principles for biological energy transduction systems and guide the design of artificial molecular machines.

  7. Non-equilibrium Microwave Plasma for Efficient High Temperature Chemistry.

    Science.gov (United States)

    van den Bekerom, Dirk; den Harder, Niek; Minea, Teofil; Gatti, Nicola; Linares, Jose Palomares; Bongers, Waldo; van de Sanden, Richard; van Rooij, Gerard

    2017-08-01

    A flowing microwave plasma based methodology for converting electric energy into internal and/or translational modes of stable molecules with the purpose of efficiently driving non-equilibrium chemistry is discussed. The advantage of a flowing plasma reactor is that continuous chemical processes can be driven with the flexibility of startup times in the seconds timescale. The plasma approach is generically suitable for conversion/activation of stable molecules such as CO2, N2 and CH4. Here the reduction of CO2 to CO is used as a model system: the complementary diagnostics illustrate how a baseline thermodynamic equilibrium conversion can be exceeded by the intrinsic non-equilibrium from high vibrational excitation. Laser (Rayleigh) scattering is used to measure the reactor temperature and Fourier Transform Infrared Spectroscopy (FTIR) to characterize in situ internal (vibrational) excitation as well as the effluent composition to monitor conversion and selectivity.

  8. The dynamics of a thermal non-equilibrium anharmonic oscillator

    OpenAIRE

    Nachbagauer, Herbert

    1995-01-01

    We propose an non-standard method to calculate non-equilibrium physical observables. Considering the generic example of an anharmonic quantum oscillator, we take advantage of the fact that the commutator algebra of second order polynomials in creation/annihilation operators closes. We solve the von~Neumann equation for the density-operator exactly in the mean field approximation and study the time evolution of the particle number and the expectation value .

  9. On nonequilibrium many-body systems III: nonlinear transport theory

    International Nuclear Information System (INIS)

    Luzzi, R.; Vasconcellos, A.R.; Algarte, A.C.S.

    1986-01-01

    A nonlinear transport theory for many-body systems arbitrarily away from equilibrium, based on the nonequilibrium statistical operator (NSO) method, is presented. Nonlinear transport equations for a basis set of dynamical quantities are derived using two equivalent treatments that may be considered far reaching generalizations of the Hilbert-Chapman-Enskog method and Mori's generalized Langevin equations method. The first case is considered in some detail and the general characteristics of the theory are discussed. (Author) [pt

  10. Nonequilibrium Energetics of a Single F1-ATPase Molecule

    OpenAIRE

    Toyabe, Shoichi; Watanabe-Nakayama, Takahiro; Okamoto, Tetsuaki; Kudo, Seishi; Muneyuki, Eiro

    2010-01-01

    Molecular motors drive mechanical motions utilizing the free energy liberated from chemical reactions such as ATP hydrolysis. Although it is essential to know the efficiency of this free energy transduction, it has been a challenge due to the system's microscopic scale. Here, we evaluate the single-molecule energetics of a rotary molecular motor, F1-ATPase, by applying a recently derived nonequilibrium equality together with an electrorotation method. We show that the sum of the heat flow thr...

  11. Fluctuations and large deviations in non-equilibrium systems

    Indian Academy of Sciences (India)

    systems. Keywords. Non-equilibrium systems; large deviations; current fluctuations. PACS Nos 02.50.-r; 05.40.-a; 05.70.Ln; 82.20.-w. 1. Introduction. The goal of this .... The model is defined as a one-dimensional lattice of L sites with open bound- .... In [2] a perturbation theory was developed to calculate µ(λ) in powers of λ.

  12. Ward identity for non-equilibrium Fermi systems

    Czech Academy of Sciences Publication Activity Database

    Velický, B.; Kalvová, Anděla; Špička, Václav

    2008-01-01

    Roč. 77, č. 4 (2008), 041201/1-041201/4 ISSN 1098-0121 R&D Projects: GA ČR GC202/07/J051 Institutional research plan: CEZ:AV0Z10100520; CEZ:AV0Z10100521 Keywords : non-equilibrium * Green’s functions * quantum transport equations * Ward identity Subject RIV: BE - Theoretical Physics Impact factor: 3.322, year: 2008

  13. Molecular-Based Optical Diagnostics for Hypersonic Nonequilibrium Flows

    Science.gov (United States)

    Danehy, Paul; Bathel, Brett; Johansen, Craig; Winter, Michael; O'Byrne, Sean; Cutler, Andrew

    2015-01-01

    This presentation package consists of seven different talks rolled up into one. These talks are all invited orals presentations in a special session at the Aviation 2015 conference and represent contributions that were made to a recent AIAA book that will be published entitled 'Hypersonic Nonequilibrium Flows: Fundamentals and Recent Advances'. Slide 5 lists the individual presentations that will be given during the special session.

  14. Mimicking Nonequilibrium Steady States with Time-Periodic Driving

    Directory of Open Access Journals (Sweden)

    O. Raz

    2016-05-01

    Full Text Available Under static conditions, a system satisfying detailed balance generically relaxes to an equilibrium state in which there are no currents. To generate persistent currents, either detailed balance must be broken or the system must be driven in a time-dependent manner. A stationary system that violates detailed balance evolves to a nonequilibrium steady state (NESS characterized by fixed currents. Conversely, a system that satisfies instantaneous detailed balance but is driven by the time-periodic variation of external parameters—also known as a stochastic pump (SP—reaches a periodic state with nonvanishing currents. In both cases, these currents are maintained at the cost of entropy production. Are these two paradigmatic scenarios effectively equivalent? For discrete-state systems, we establish a mapping between nonequilibrium stationary states and stochastic pumps. Given a NESS characterized by a particular set of stationary probabilities, currents, and entropy production rates, we show how to construct a SP with exactly the same (time-averaged values. The mapping works in the opposite direction as well. These results establish a proof of principle: They show that stochastic pumps are able to mimic the behavior of nonequilibrium steady states, and vice versa, within the theoretical framework of discrete-state stochastic thermodynamics. Nonequilibrium steady states and stochastic pumps are often used to model, respectively, biomolecular motors driven by chemical reactions and artificial molecular machines steered by the variation of external, macroscopic parameters. Our results loosely suggest that anything a biomolecular machine can do, an artificial molecular machine can do equally well. We illustrate this principle by showing that kinetic proofreading, a NESS mechanism that explains the low error rates in biochemical reactions, can be effectively mimicked by a constrained periodic driving.

  15. Crossover from Nonequilibrium Fractal Growth to Equilibrium Compact Growth

    DEFF Research Database (Denmark)

    Sørensen, Erik Schwartz; Fogedby, Hans C.; Mouritsen, Ole G.

    1988-01-01

    Solidification controlled by vacancy diffusion is studied by Monte Carlo simulations of a two-dimensional Ising model defined by a Hamiltonian which models a thermally driven fluid-solid phase transition. The nonequilibrium morphology of the growing solid is studied as a function of time as the s...... as the system relaxes into equilibrium described by a temperature. At low temperatures the model exhibits fractal growth at early times and crossover to compact solidification as equilibrium is approached....

  16. Use of an electron reflector to improve dose uniformity at the vertex during total skin electron therapy

    International Nuclear Information System (INIS)

    Peters, V.G.

    2000-01-01

    Purpose: The vertex of the scalp is always tangentially irradiated during total skin electron therapy (TSET). This study was conducted to determine the dose distribution at the vertex for a commonly used irradiation technique and to evaluate the use of an electron reflector, positioned above the head, as a means of improving the dose uniformity. Methods and Materials: Phantoms, simulating the head of a patient, were irradiated using our standard procedure for TSET. The technique is a six-field irradiation using dual angled electron beams at a treatment distance of 3.6 meters. Vertex dosimetry was performed using ionization methods and film. Measurements were made for an unmodified 6 MeV electron beam and for a 4 MeV beam obtained by placing an acrylic scattering plate in the beam line. Studies were performed to examine the effect of electron scattering on vertex dose when a lead reflector, 50 x 50 cm in area, was positioned above the phantom. Results: The surface dose at the vertex, in the absence of the reflector, was found to be less than 40% of the prescribed skin dose. Use of the lead reflector increased this value to 73% for the 6 MeV beam and 99% for the degraded 4 MeV beam. Significant improvements in depth dose were also observed. The dose enhancement is not strongly dependent on reflector distance or angulation since the reflector acts as a large source of broadly scattered electrons. Conclusion: The vertex may be significantly underdosed using standard techniques for total skin electron therapy. Use of an electron reflector improves the dose uniformity at the vertex and may reduce or eliminate the need for supplemental irradiation

  17. Non-equilibrium Quasi-Chemical Nucleation Model

    Science.gov (United States)

    Gorbachev, Yuriy E.

    2018-04-01

    Quasi-chemical model, which is widely used for nucleation description, is revised on the basis of recent results in studying of non-equilibrium effects in reacting gas mixtures (Kolesnichenko and Gorbachev in Appl Math Model 34:3778-3790, 2010; Shock Waves 23:635-648, 2013; Shock Waves 27:333-374, 2017). Non-equilibrium effects in chemical reactions are caused by the chemical reactions themselves and therefore these contributions should be taken into account in the corresponding expressions for reaction rates. Corrections to quasi-equilibrium reaction rates are of two types: (a) spatially homogeneous (caused by physical-chemical processes) and (b) spatially inhomogeneous (caused by gas expansion/compression processes and proportional to the velocity divergency). Both of these processes play an important role during the nucleation and are included into the proposed model. The method developed for solving the generalized Boltzmann equation for chemically reactive gases is applied for solving the set of equations of the revised quasi-chemical model. It is shown that non-equilibrium processes lead to essential deviation of the quasi-stationary distribution and therefore the nucleation rate from its traditional form.

  18. States of Water in Non-Equilibrium Glassy Polymers

    Science.gov (United States)

    Davis, Eric; Elabd, Yossef

    2013-03-01

    For many applications (e.g., packaging, medical devices) a deeper fundamental understanding of the molecular nature of water in glassy polymer coatings is of significant interest. In this study, the sorption and diffusion of water in two glassy polymers, poly(methyl methacrylate) (PMMA) and poly(styrene) (PS), were measured with both quartz crystal microbalance (QSM) and time-resolved Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy. Non-Fickian diffusion was observed in both PMMA and PS using both experimental techniques due to the non-equilibrium state of the polymers. The specific states of water were observed with FTIR-ATR spectroscopy, where dimers exist in PMMA below a critical concentration and larger clusters were observed above this concentration. Contrastingly, water only exists in PS as larger clusters over the entire sorption isotherm. A correlation between the states of water and the diffusive activation energy of water was observed. Additionally, the pseudo-equilibrium water sorption isotherms in PMMA and PS were accurately predicted with the non-equilibrium statistical associating fluid theory (NE-SAFT). We predict that the combination of time-resolved FTIR-ATR spectroscopy and NE-SAFT can be used on other water-glassy polymer systems to provide a molecular understanding of non-equilibrium sorption and diffusion.

  19. Design and construction of a Vertex Chamber and measurement of the average B-Hadron lifetime

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, H.N.

    1987-10-01

    Four parameters describe the mixing of the three quark generations in the Standard Model of the weak charged current interaction. These four parameters are experimental inputs to the model. A measurement of the mean lifetime of hadrons containing b-quarks, or B-Hadrons, constrains the magnitudes of two of these parameters. Measurement of the B-Hadron lifetime requires a device that can measure the locations of the stable particles that result from B-Hadron decay. This device must function reliably in an inaccessible location, and survive high radiation levels. We describe the design and construction of such a device, a gaseous drift chamber. Tubes of 6.9 mm diameter, having aluminized mylar walls of 100 ..mu..m thickness are utilized in this Vertex Chamber. It achieves a spatial resolution of 45 ..mu..m, and a resolution in extrapolation to the B-Hadron decay location of 87 ..mu..m. Its inner layer is 4.6 cm from e/sup +/e/sup -/ colliding beams. The Vertex Chamber is situated within the MAC detector at PEP. We have analyzed botht he 94 pb/sup -1/ of integrated luminosity accumulated at ..sqrt..s = 29 GeV with the Vertex Chamber in place as well as the 210 pb/sup -1/ accumulated previously. We require a lepton with large momentum transverse to the event thrust axis to obtain a sample of events enriched in B-Hadron decays. The distribution of signed impact parameters of all tracks in these events is used to measure the B-Hadron flight distance, and hence lifetime. 106 refs., 79 figs., 20 tabs.

  20. LOGISTIC NETWORK REGRESSION FOR SCALABLE ANALYSIS OF NETWORKS WITH JOINT EDGE/VERTEX DYNAMICS.

    Science.gov (United States)

    Almquist, Zack W; Butts, Carter T

    2014-08-01

    Change in group size and composition has long been an important area of research in the social sciences. Similarly, interest in interaction dynamics has a long history in sociology and social psychology. However, the effects of endogenous group change on interaction dynamics are a surprisingly understudied area. One way to explore these relationships is through social network models. Network dynamics may be viewed as a process of change in the edge structure of a network, in the vertex set on which edges are defined, or in both simultaneously. Although early studies of such processes were primarily descriptive, recent work on this topic has increasingly turned to formal statistical models. Although showing great promise, many of these modern dynamic models are computationally intensive and scale very poorly in the size of the network under study and/or the number of time points considered. Likewise, currently used models focus on edge dynamics, with little support for endogenously changing vertex sets. Here, the authors show how an existing approach based on logistic network regression can be extended to serve as a highly scalable framework for modeling large networks with dynamic vertex sets. The authors place this approach within a general dynamic exponential family (exponential-family random graph modeling) context, clarifying the assumptions underlying the framework (and providing a clear path for extensions), and they show how model assessment methods for cross-sectional networks can be extended to the dynamic case. Finally, the authors illustrate this approach on a classic data set involving interactions among windsurfers on a California beach.

  1. The high energy behavior of QCD. The effective action and the triple-Pomeron-vertex

    Energy Technology Data Exchange (ETDEWEB)

    Hentschinski, Martin

    2009-07-15

    We study integrations over light-cone momenta in the high energy effective action of QCD. After a brief review of the effective action, we arrive on a regularization mechanism from matching of effective action diagrams with QCD diagrams, which we apply to a re-derivation of the reggeized gluon and of the BFKL-equation. We study consequences of the proposed regularization on the analytic structure of 2{yields}3 and 2{yields}4 production amplitudes in the Multi-Regge-Kinematics. We derive a certain part of the 1-loop corrections to the production vertex and demonstrate that they yield the on-set of corrections demanded by the Steinmann-relations. The Reggeon-Particle-2-Reggeon vertex is determined and applied to the construction of various signature configurations of the production amplitudes. We extend the proposed regularization method to states of three and four reggeized gluons and propose a supplement to the effective Lagrangian. We derive vertices for the 1-3 and 2-4 reggeized-gluon-transition inside the elastic amplitude and verify that signature conservation is obeyed. Integral equations for the state of three and four reggeized gluons are formulated and shown to be in accordance with a result by Bartels and Wuesthoff. In a second part we investigate the high-energy behavior of QCD for different surface topologies of color graphs. After a brief review of the planar limit (bootstrap and gluon reggeization) and of the cylinder topology (BFKL) we investigate the 3{yields}3 scattering in the triple Regge limit which belongs to the pair-of-pants topology. We re-derive the triple Pomeron vertex function and show that it belongs to a specific set of graphs in color space which we identify as the analog of the Mandelstam diagram. We then extend the study to the high-energy behavior of N=4 SYM where we find a new class of color graphs not present in QCD. (orig.)

  2. A DNA Computing Model for the Graph Vertex Coloring Problem Based on a Probe Graph

    Directory of Open Access Journals (Sweden)

    Jin Xu

    2018-02-01

    Full Text Available The biggest bottleneck in DNA computing is exponential explosion, in which the DNA molecules used as data in information processing grow exponentially with an increase of problem size. To overcome this bottleneck and improve the processing speed, we propose a DNA computing model to solve the graph vertex coloring problem. The main points of the model are as follows: ① The exponential explosion problem is solved by dividing subgraphs, reducing the vertex colors without losing the solutions, and ordering the vertices in subgraphs; and ② the bio-operation times are reduced considerably by a designed parallel polymerase chain reaction (PCR technology that dramatically improves the processing speed. In this article, a 3-colorable graph with 61 vertices is used to illustrate the capability of the DNA computing model. The experiment showed that not only are all the solutions of the graph found, but also more than 99% of false solutions are deleted when the initial solution space is constructed. The powerful computational capability of the model was based on specific reactions among the large number of nanoscale oligonucleotide strands. All these tiny strands are operated by DNA self-assembly and parallel PCR. After thousands of accurate PCR operations, the solutions were found by recognizing, splicing, and assembling. We also prove that the searching capability of this model is up to O(359. By means of an exhaustive search, it would take more than 896 000 years for an electronic computer (5 × 1014 s−1 to achieve this enormous task. This searching capability is the largest among both the electronic and non-electronic computers that have been developed since the DNA computing model was proposed by Adleman’s research group in 2002 (with a searching capability of O(220. Keywords: DNA computing, Graph vertex coloring problem, Polymerase chain reaction

  3. Design and construction of a Vertex Chamber and measurement of the average B-Hadron lifetime

    International Nuclear Information System (INIS)

    Nelson, H.N.

    1987-10-01

    Four parameters describe the mixing of the three quark generations in the Standard Model of the weak charged current interaction. These four parameters are experimental inputs to the model. A measurement of the mean lifetime of hadrons containing b-quarks, or B-Hadrons, constrains the magnitudes of two of these parameters. Measurement of the B-Hadron lifetime requires a device that can measure the locations of the stable particles that result from B-Hadron decay. This device must function reliably in an inaccessible location, and survive high radiation levels. We describe the design and construction of such a device, a gaseous drift chamber. Tubes of 6.9 mm diameter, having aluminized mylar walls of 100 μm thickness are utilized in this Vertex Chamber. It achieves a spatial resolution of 45 μm, and a resolution in extrapolation to the B-Hadron decay location of 87 μm. Its inner layer is 4.6 cm from e + e - colliding beams. The Vertex Chamber is situated within the MAC detector at PEP. We have analyzed botht he 94 pb -1 of integrated luminosity accumulated at √s = 29 GeV with the Vertex Chamber in place as well as the 210 pb -1 accumulated previously. We require a lepton with large momentum transverse to the event thrust axis to obtain a sample of events enriched in B-Hadron decays. The distribution of signed impact parameters of all tracks in these events is used to measure the B-Hadron flight distance, and hence lifetime. 106 refs., 79 figs., 20 tabs

  4. Managing Bias Leakage Currents and High Data Rates in the BABAR Silicon Vertex Tracker

    CERN Document Server

    Garra-Tico, J; Bondioli, M; Bruinsma, M; Curry, S; Kirkby, D; Burke, S; Callahan, D; Campagnari, C; Cunha, A; Hale, D; Kyre, S; Richman, J; Beck, T; Eisner, A M; Kroseberg, J; Lockman, W S; Nesom, G; Seiden, A; Spradlin, P; Winstrom, L; Brown, D; Dardin, S; Goozen, F; Kerth, L T; Lynch, G; Roe, N A; Anderson, J; Chen, C; Lae, C K; Roberts, D; Simi, G; Tuggle, J; Lazzaro, A; Lombardo, V; Palombo, F; Ratti, L; Angelini, C; Batignani, G; Bettarini, S; Bosi, F; Bucci, F; Calderini, G; Carpinelli, M; Ceccanti, M; Cenci, R; Cervelli, A; Forti, F; Giorgi, M A; Lusiani, A; Mammini, P; Manfredi, P F; Marchiori, G; Mazur, M; Morganti, M; Morsani, F; Neri, N; Paoloni, E; Profeti, A; Rama, M; Rizzo, G; Walsh, J; Elmer, P; Long, O; Charles, E; Perazzo, A; Burchat, P; Edwards, A J; Miyashita, T S; Majewski, S; Petersen, B A; Bona, M; Bianchi, F; Gamba, D; Trapani, P; Bomben, M; Bosisio, L; Cartaro, C; Dittongo, S; Lanceri, L; Vitale, L; Azzolini, V; Lopez-March, N; Gao, Y Y; Gritsan, A V; Guo, Z J

    2008-01-01

    The silicon vertex tracker at the BABAR experiment is the primary device used in measuring the distance between B0 and meson decay vertices for the extraction of CP asymmetries. It consists of five layers of double-sided, AC-coupled silicon modules, read out by custom integrated circuits. It has run well consistently for eight years. I report on three years of experience in managing problematic bias leakage currents in the fourth layer. In addition, I report on recent success in decreasing the data acquisition time by reducing the readout window.

  5. Soft yet Sharp Interfaces in a Vertex Model of Confluent Tissue

    Science.gov (United States)

    Sussman, Daniel M.; Schwarz, J. M.; Marchetti, M. Cristina; Manning, M. Lisa

    2018-01-01

    How can dense biological tissue maintain sharp boundaries between coexisting cell populations? We explore this question within a simple vertex model for cells, focusing on the role of topology and tissue surface tension. We show that the ability of cells to independently regulate adhesivity and tension, together with neighbor-based interaction rules, lets them support strikingly unusual interfaces. In particular, we show that mechanical- and fluctuation-based measurements of the effective surface tension of a cellular aggregate yield different results, leading to mechanically soft interfaces that are nevertheless extremely sharp.

  6. The STAR silicon vertex tracker: a large area silicon drift detector

    CERN Document Server

    Lynn, D; Beuttenmüller, Rolf H; Caines, H; Chen, W; Dimassimo, D; Dyke, H; Elliot, D; Eremin, V; Grau, M; Hoffmann, G W; Humanic, T; Ilyashenko, Yu S; Kotov, I; Kraner, H W; Kuczewski, P; Leonhardt, B; Li, Z; Liaw, C J; Lo Curto, G; Middelkamp, P; Minor, R; Munhoz, M; Ott, G; Pandey, S U; Pruneau, C A; Rykov, V L; Schambach, J; Sedlmeir, J; Soja, B; Sugarbaker, E R; Takahashi, J; Wilson, K; Wilson, R

    2000-01-01

    The Solenoidal Tracker At RHIC-Silicon Vertex Tracker (STAR-SVT) is a three barrel microvertex detector based upon silicon drift detector technology. As designed for the STAR-SVT, silicon drift detectors (SDDs) are capable of providing unambiguous two-dimensional hit position measurements with resolutions on the order of 20 mu m in each coordinate. Achievement of such resolutions, particularly in the drift direction coordinate, depends upon certain characteristics of silicon and drift detector geometry that are uniquely critical for silicon drift detectors hit measurements. Here we describe features of the design of the STAR-SVT SDDs and the front-end electronics that are motivated by such characteristics.

  7. Vertex G4 -serverin käyttöönotto ja johtotiekomponenttien suunnittelu

    OpenAIRE

    Tyni, Jani

    2015-01-01

    Opinnäytetyön tavoitteena oli tehdä johtotiekomponentti-suunnittelu ohjeineen koululle Vertex G4 -ohjelmistoon opetuskäyttöä varten, jotta se olisi helposti siirrettävi-ssä ohjelmaan sekä mallinnettavissa kokoonpanoksi käyttäen ohjelmassa jo olevaa kaapelihyllysovellusta. Lisäksi ohjelmasta tulisi olla tulostettavissa tarvikelista kokonaisuudessaan asennuksia varten. Työssä käytettiin Meka Pro Oy:n johtotiekomponentteja 3D-mallinnettuna STEPtiedostomuodossa sekä Vertexiltä käytettävissä o...

  8. Identification of events with a secondary vertex in the experiment EXCHARM

    International Nuclear Information System (INIS)

    Bonyushkina, A.Yu.; Ivanov, V.V.; Potrebenikov, Yu.K.; Progulova, T.B.; Tatishvili, G.T.

    1996-01-01

    A simple algorithm for identifying events with secondary vertices (signal events) is suggested. The differences R x , R y between the largest and the smallest impact parameters D i of the tracks belonging to each of the events analyzed are used in establishing the identification criteria for signal and background events. An effective method for identifying the tracks associated with a particular secondary vertex in an event is developed. The method is based on the differences between the asymmetries exhibited by the sets D i for individual signal events and background events. The algorithm has been tested using simulated data. 12 refs., 7 figs

  9. Vertex of three and four gluons in the Yang-Mills theory

    International Nuclear Information System (INIS)

    Brandt, F.T.C.

    1986-01-01

    In a general covariant gauge, the structure of the three-point function with one and two external gluons on shell is studied. The contributions which result in the one-loop approximation are expressed in terms of simple functions containing collinear and soft singularities. Furthermore, the contributions asociated with the four-point vertex when all external gluons are on-sheel, are analysed. As an application of these results, the infrared structure of the gluon-gluon scattering amplitude, is studied. (author) [pt

  10. Bounding the flavor-violating Hbs vertex from the B → Xsγ decay

    International Nuclear Information System (INIS)

    Aranda, J I; Ramirez-Zavaleta, F; Tututi, E S; Montano, J; Toscano, J J

    2011-01-01

    The nondiagonal Hbs coupling within the context of an effective Yukawa sector that comprises SU L (2) x U Y (1)-invariant operators of up to dimension six is studied. The recent experimental result on B → X sγ with hard photons is employed to constrain the Hbs vertex, with which the branching ratio for the B s → γγ decay is estimated. It is found that the B s → γγ decay can reach a branching ratio of the order of 4 x 10 -8 .

  11. Spin glass phase transitions in the random feedback vertex set problem

    OpenAIRE

    Qin, Shao-Meng; Zeng, Ying; Zhou, Hai-Jun

    2016-01-01

    A feedback vertex set (FVS) of an undirected graph contains vertices from every cycle of this graph. Constructing a FVS of sufficiently small cardinality is very difficult in the worst cases, but for random graphs this problem can be efficiently solved after converting it into an appropriate spin glass model [H.-J. Zhou, Eur. Phys. J. B 86 (2013) 455]. In the present work we study the local stability and the phase transition properties of this spin glass model on random graphs. For both regul...

  12. A General Approximation of Quantum Graph Vertex Couplings by Scaled Schrodinger Operators on Thin Branched Manifolds

    Czech Academy of Sciences Publication Activity Database

    Exner, Pavel; Post, O.

    2013-01-01

    Roč. 322, č. 1 (2013), s. 207-227 ISSN 0010-3616 R&D Projects: GA ČR GAP203/11/0701; GA MŠk LC06002 Institutional support: RVO:61389005 Keywords : quantum graph * vertex coupling * tubular network * approximation Subject RIV: BE - Theoretical Physics Impact factor: 1.901, year: 2013 http://download.springer.com/static/pdf/685/art%253A10.1007%252Fs00220-013-1699-9.pdf?auth66=1379859821_26f2df9c1c7e0997b290a90ec2fdfc7e&ext=.pdf

  13. A facility for long term evaluation and quality assurance of LHCb Vertex Detector modules

    CERN Document Server

    Marinho, F; Dimattia, R; Doherty, F; Dumps, R; Gersabeck, M; Melone, J; Parkes, C; Saavedra, A; Tobin, M

    2007-01-01

    This note describes the facility developed for long term evaluation and quality assurance of the LHCb Vertex Detector modules, known as the 'Glasgow Burn-in System'. This facility was developed to ensure that the modules conform to stringent quality levels. The system was able to uncover any weaknesses that could be introduced during the manufacturing and assembly of the components or during the transport of the modules to CERN. The system consisted of: a high resolution microscope for visual inspections; and a burn-in system to operate cooled modules in vacuum. The main components of the burn-in system were a vacuum system, a cooling system and a DAQ system.

  14. Cost effectiveness of using moxibustion to correct non-vertex presentation.

    Science.gov (United States)

    García-Mochón, Leticia; Martín, José J; Aranda-Regules, José Manuel; Rivas-Ruiz, Francisco; Vas, Jorge

    2015-04-01

    To analyse the cost effectiveness of using the moxibustion technique to correct non-vertex presentation and to reduce the number of caesarean sections performed at term. A deterministic model of decision analysis has been developed to analyse the cost of treatment in which heat is applied by moxibustion (the combustion of Artemisia vulgaris) at acupuncture point BL67 for pregnant women with non-vertex fetal position at 33-35 weeks' gestation. This approach was compared with conventional treatment recommendations based on the knee-chest posture technique. The costs were obtained mainly from data provided by the Andalusian Public Health System. Effectiveness data for the baseline analysis were taken from a previous clinical study. A secondary analysis was performed based on a meta-analysis conducted using random effects analysis, by reference to studies published in recent systematic reviews of moxibustion versus conventional treatment, in order to make the results generalisable to other healthcare settings. Deterministic and probabilistic sensitivity analyses were performed under diverse assumptions to assess the uncertainty of the result. The baseline analysis shows that the application of moxibustion prevents 8.92% of deliveries with non-vertex presentation compared with conventional treatment, with an average cost saving of €107.11 per delivery, mainly due to the cost saving from avoiding the need for caesarean section. The meta-analysis revealed a relative risk of the version of non-vertex presentation at term of 0.34 (95% CI 0.16 to 0.76). The sensitivity analysis showed that moxibustion can avoid 0.34 caesarean sections, with an incremental cost per delivery ranging from €68 to -€640 for moxibustion versus conventional treatment. Moxibustion treatment applied at acupuncture point BL67 can avoid the need for caesarean section and achieve cost savings for the healthcare system in comparison with conventional treatment. Published by the BMJ Publishing

  15. Insights into the Quark–Gluon Vertex from Lattice QCD and Meson Spectroscopy

    International Nuclear Information System (INIS)

    Rojas, E.; El-Bennich, B.; Melo, J.P.B.C. de; Paracha, M. Ali.

    2015-01-01

    By comparing successful quark–gluon vertex interaction models with the corresponding interaction extracted from lattice-QCD data on the quark’s propagator, we identify common qualitative features which could be important to tune future interaction models beyond the rainbow ladder approximation. Clearly, a quantitative comparison is conceptually not simple, but qualitatively the results suggest that a realistic interaction should be relatively broad with a strong support at about 0.4–0.6 GeV and infrared-finite. (author)

  16. Development of CMOS Pixel Sensors fully adapted to the ILD Vertex Detector Requirements

    CERN Document Server

    Winter, Marc; Besson, Auguste; Claus, Gilles; Dorokhov, Andrei; Goffe, Mathieu; Hu-Guo, Christine; Morel, Frederic; Valin, Isabelle; Voutsinas, Georgios; Zhang, Liang

    2012-01-01

    CMOS Pixel Sensors are making steady progress towards the specifications of the ILD vertex detector. Recent developments are summarised, which show that these devices are close to comply with all major requirements, in particular the read-out speed needed to cope with the beam related background. This achievement is grounded on the double- sided ladder concept, which allows combining signals generated by a single particle in two different sensors, one devoted to spatial resolution and the other to time stamp, both assembled on the same mechanical support. The status of the development is overviewed as well as the plans to finalise it using an advanced CMOS process.

  17. Development of ultra-light pixelated ladders for an ILC vertex detector

    CERN Document Server

    Chon-Sen, N.; Claus, G.; De Masi, R.; Deveaux, M.; Dulinski, W.; Goffe, M.; Goldstein, J.; Gregor, I.-M.; Hu-Guo, Ch.; Imhoff, M.; Muntz, C.; Nomerotski, A.; Santos, C.; Schrader, C.; Specht, M.; Stroth, J.; Winter, M.

    2010-01-01

    The development of ultra-light pixelated ladders is motivated by the requirements of the ILD vertex detector at ILC. This paper summarizes three projects related to system integration. The PLUME project tackles the issue of assembling double-sided ladders. The SERWIETE project deals with a more innovative concept and consists in making single-sided unsupported ladders embedded in an extra thin plastic enveloppe. AIDA, the last project, aims at building a framework reproducing the experimental running conditions where sets of ladders could be tested.

  18. Effective-range parameters and vertex constants for Λ-nuclear systems

    Science.gov (United States)

    Rakityansky, S. A.; Gopane, I. M.

    For a wide range of the core-nuclei (6 ≤ A ≤ 207), the scattering lengths, effective radii, and the other effective-range parameters (up to the order ˜ k8) for the angular momentum ℓ = 0, 1, 2 are calculated within a two-body ΛA-model. For the same hypernuclear systems, the S-matrix residues as well as the corresponding Nuclear-Vertex and Asymptotic-Normalization constants (NVC’s and ANC’s) for the bound states are also found.

  19. The Urban Function of the Infraordinary: Dry Cleaners as Social Vertexes

    DEFF Research Database (Denmark)

    Lunde Nielsen, Espen

    2015-01-01

    of social coexistence that has ‘a function that is separate from their practical use’ (Jorn 1954). A London dry cleaner serves as testing ground, employing critical spatial practices and creative writing as research tools. The dry cleaner does not simply clean clothes, but is a social vertex and physical...... through allowing for occupation, inhabitation and co-authoring. Hence, these latent qualities and spatial materiality of the infraordinary form vital components of the social dimension of the city and points towards a recalibration of current urban practices....

  20. Pin Photodiodes for Radiation Monitoring and Protection in the Babar Silicon Vertex Tracker

    Science.gov (United States)

    Meyer, T. I.

    We discuss the design, implementation and performance of the radiation monitoring and protection system used by the Silicon Vertex Tracker (SVT) in the BaBar detector. Using 12 reverse-biased PIN photodiodes mounted around the beampipe near the IP, we are able to provide instantaneous radiation dose rates, absorbed dose integrals, and active protection that aborts the circulating beams in the PEP-II storage ring when radiation levels exceed user-defined thresholds. The systems has reliably protected the SVT from excessive radiation damage and has also served as a key diagnostic tool in understanding radiation backgrounds at PEP-II.