Sample records for wave function impact

  1. The bootstrap for impact factors and the gluon wave function

    E-print Network

    M. Braun; G. P. Vacca

    1999-10-21

    Using the results recently obtained for the non-forward quark and gluon impact factors, it is shown that their form in the gluon colour channel is consistent with the ``third bootstrap condition'', namely, that they should be proportional to the gluon wave function. The gluon wave function found from this assumption is used to write the full bootstrap condition for the gluonic potential in the next-to-leading order.

  2. Impact of permeability on seismoelectric transfer function of P waves

    NASA Astrophysics Data System (ADS)

    Holzhauer, J.; Bordes, C.; Oppermann, F.; Brito, D.; Yaramanci, U.

    2012-04-01

    Recent developments in the understanding of seismoelectrics have shown its potential relevance for porous media characterization with particular focus on permeability estimations. According to promising theoretical and numerical studies, permeability should influence the seismoelectric transfer function at higher frequencies. The dynamic seismoelectric transfer function E(?)/ ü(?), where E relates to the coseismic electric field induced by the seismic particle acceleration ü, is expected to increase with increasing permeabilities when crossing the Biot transition frequency. Still, only few experiments have been developed on that matter so far. To address the transfer function dependence on permeability, we adapted a column experiment to comply with steady-state permeability estimations. These observations were run in-situ, during the fluid-balancing phase prior to seismoelectric measurements. The 50 cm-long column had previously been carefully filled with perfectly rounded glass beads. The use of sorted glass beads is expected to achieve similar porosities reproducible throughout the experiment, opposed to varying permeabilities depending on the introduced particle size. The acoustic source delivered compressional waves with an optimal effect limited to the [1-3] kHz frequency range. These limitations are due to strong seismic attenuation in uncompacted porous media on one side, and to the dilemma of observing propagation in downsized laboratory setup on the other. First results validated the experimental protocol in terms of porosity/permeability independence: for particle size varying between 100 ?m and 500 ?m, permeability varied by a factor 20, with a maximum by 5.10-11 m2, while porosity remained by 39 ± 2 % during the whole experiment. Further investigations are being led regarding the normalised transfer function, corrected for both the fluid conductivity and the seismic energy. For that purpose, we compare the dependence of our measured transfer function on permeability at a given frequency, to that predicted by synthetics, computed using our experimental permeabilities.

  3. Impact of 120-W 2-?m continuous wave laser vapoenucleation of the prostate on sexual function.

    PubMed

    Wang, Yubin; Shao, Jinkai; Lu, Yongning; Lü, Yongan; Li, Xiaodong

    2014-03-01

    The objective of this work is to evaluate the impact of 120-W 2-?m continuous wave (cw) laser vapoenucleation of the prostate in patients with benign prostatic hyperplasia (BPH) on sexual function. One hundred twenty-two consecutive patients with BPH were retrospectively collected in this study and were classified into two groups for surgical treatment with 2-?m cw laser vapoenucleation or transurethral resection of the prostate (TURP). International Index of Erectile Function (IIEF) and general assessment questions were completed before and 12 months after treatment to determine the impact on sexual function. A total of 33 patients (52.4%) in group 1 and 31 (52.5%) in group 2 reported various degrees of erectile dysfunction before surgery. Interestingly, an increase in IIEF-EF score by 2 points was reported by 16 (25.4%) and 14 (23.7%) patients, respectively, and mean EF score did show a marginal but not significant increase postoperatively in both group. Differences about orgasmic intercourse satisfaction, sexual desire domain, and overall satisfaction scores in each group were not significant between preoperative and postoperative, but there was a significant decrease in the orgasmic function domain score at 12 months postoperation in both groups (p?impact on sexual function. No significant erectile function improvement was observed after surgery, but these two techniques significantly lowered the IIEF orgasmic function domain and this was mainly caused by retrograde ejaculation. PMID:23828495

  4. Baryon scattering at high energies: wave function, impact factor, and gluon radiation

    E-print Network

    J. Bartels; L. Motyka

    2007-11-14

    The scattering of a baryon consisting of three massive quarks is investigated in the high energy limit of perturbative QCD. A model of a relativistic proton-like wave function, dependent on valence quark longitudinal and transverse momenta and on quark helicities, is proposed, and we derive the baryon impact factors for two, three and four t-channel gluons. We find that the baryonic impact factor can be written as a sum of three pieces: in the first one a subsystem consisting of two of the three quarks behaves very much like the quark-antiquark pair in gamma* scattering, whereas the third quark acts as a spectator. The second term belongs to the odderon, whereas in the third (C-even) piece all three quarks participate in the scattering. This term is new and has no analogue in gamma* scattering. We also study the small x evolution of gluon radiation for each of these three terms. The first term follows the same pattern of gluon radiation as the gamma*-initiated quark-antiquark dipole, and, in particular, it contains the BFKL evolution followed by the 2-->4 transition vertex (triple Pomeron vertex). The odderon-term is described by the standard BKP evolution, and the baryon couples to both known odderon solutions, the Janik-Wosiek solution and the BLV solution. Finally, the t-channel evolution of the third term starts with a three reggeized gluon state which then, via a new 3-->4 transition vertex, couples to the four gluon (two-Pomeron) state. We briefly discuss a few consequences of these findings, in particular the pattern of unitarization of high energy baryon scattering amplitudes.

  5. Photon wave functions

    NASA Astrophysics Data System (ADS)

    Sipe, J. E.

    1995-09-01

    We argue that a photon wave function can be introduced if one is willing to redefine, in what we feel is a physically meaningful way, what one wishes to mean by such a wave function. The generation of a photon wave function by a spontaneously emitting atom is discussed.

  6. The photon wave function

    NASA Astrophysics Data System (ADS)

    Muthukrishnan, A.; Scully, M. O.; Zubairy, M. S.

    2005-08-01

    We review and sharpen the concept of a photon wave function based on the quantum theory of light. We argue that a point-like atom serves as the archetype for both the creation and detection of photons. Spontaneous emission from atoms provides a spatially localized source of photon states that serves as a natural wave packet basis for quantum states of light. Photodetection theory allows us to give operational meaning to the photon wave function which, for single photons, is analogous to the electric field in classical wave optics. Entanglement between photons, and the uniquely quantum phenomena that result from it, are exemplified by two-photon wave functions.

  7. Holographic Tunneling Wave Function

    E-print Network

    Gabriele, Conti; van der Woerd, Ellen

    2015-01-01

    The Hartle-Hawking wave function in cosmology can be viewed as a decaying wave function with anti-de Sitter (AdS) boundary conditions. We show that the growing wave function in AdS familiar from Euclidean AdS/CFT is equivalent, semiclassically and up to surface terms, to the tunneling wave function in cosmology. The cosmological measure in the tunneling state is given by the partition function of certain relevant deformations of CFTs on a locally AdS boundary. We compute the partition function of finite constant mass deformations of the O(N) vector model on the round three sphere and show this qualitatively reproduces the behaviour of the tunneling wave function in Einstein gravity coupled to a positive cosmological constant and a massive scalar. We find the amplitudes of inhomogeneities are not damped in the holographic tunneling state.

  8. Holographic Tunneling Wave Function

    E-print Network

    Conti Gabriele; Thomas Hertog; Ellen van der Woerd

    2015-06-24

    The Hartle-Hawking wave function in cosmology can be viewed as a decaying wave function with anti-de Sitter (AdS) boundary conditions. We show that the growing wave function in AdS familiar from Euclidean AdS/CFT is equivalent, semiclassically and up to surface terms, to the tunneling wave function in cosmology. The cosmological measure in the tunneling state is given by the partition function of certain relevant deformations of CFTs on a locally AdS boundary. We compute the partition function of finite constant mass deformations of the O(N) vector model on the round three sphere and show this qualitatively reproduces the behaviour of the tunneling wave function in Einstein gravity coupled to a positive cosmological constant and a massive scalar. We find the amplitudes of inhomogeneities are not damped in the holographic tunneling state.

  9. Adaptive multiconfigurational wave functions

    SciTech Connect

    Evangelista, Francesco A., E-mail: francesco.evangelista@emory.edu [Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322 (United States)

    2014-03-28

    A method is suggested to build simple multiconfigurational wave functions specified uniquely by an energy cutoff ?. These are constructed from a model space containing determinants with energy relative to that of the most stable determinant no greater than ?. The resulting ?-CI wave function is adaptive, being able to represent both single-reference and multireference electronic states. We also consider a more compact wave function parameterization (?+SD-CI), which is based on a small ?-CI reference and adds a selection of all the singly and doubly excited determinants generated from it. We report two heuristic algorithms to build ?-CI wave functions. The first is based on an approximate prescreening of the full configuration interaction space, while the second performs a breadth-first search coupled with pruning. The ?-CI and ?+SD-CI approaches are used to compute the dissociation curve of N{sub 2} and the potential energy curves for the first three singlet states of C{sub 2}. Special attention is paid to the issue of energy discontinuities caused by changes in the size of the ?-CI wave function along the potential energy curve. This problem is shown to be solvable by smoothing the matrix elements of the Hamiltonian. Our last example, involving the Cu{sub 2}O{sub 2}{sup 2+} core, illustrates an alternative use of the ?-CI method: as a tool to both estimate the multireference character of a wave function and to create a compact model space to be used in subsequent high-level multireference coupled cluster computations.

  10. Boundary conditions of the exact impulse wave function

    SciTech Connect

    Gravielle, M.; Miraglia, J.E. [Instituto de Astronomia y Fisica del Espacio, Consejo Nacional de Investigaciones Cientificas y Tecnicas, Casilla de Correo 67, Sucursal 28, 1428 Buenos Aires (Argentina)] [Instituto de Astronomia y Fisica del Espacio, Consejo Nacional de Investigaciones Cientificas y Tecnicas, Casilla de Correo 67, Sucursal 28, 1428 Buenos Aires (Argentina)

    1997-02-01

    The behavior of the exact impulse wave function is investigated at intermediate and high impact energies. Numerical details of the wave function and its perturbative potential are reported. We conclude that the impulse wave function does not tend to the proper Coulomb asymptotic limit. For electron capture, however, it is shown that the impulse wave function produces reliable probabilities even for intermediate velocities and symmetric collision systems. {copyright} {ital 1997} {ital The American Physical Society}

  11. Wave propagation and impact in composite materials

    NASA Technical Reports Server (NTRS)

    Moon, F. C.

    1975-01-01

    Anisotropic waves in composites are considered, taking into account wave speeds, wave surfaces, flexural waves in orthotropic plates, surface waves, edge waves in plates, and waves in coupled composite plates. Aspects of dispersion in composites are discussed, giving attention to pulse propagation and dispersion, dispersion in rods and plates, dispersion in a layered composite, combined material and structural dispersion, continuum theories for composites, and variational methods for periodic composites. The characteristics of attenuation and scattering processes are examined and a description is given of shock waves and impact problems in composites. A number of experiments are also reported.

  12. Multiphoton wave function after Kerr interaction

    NASA Astrophysics Data System (ADS)

    Koshino, Kazuki

    2008-08-01

    The multiphoton wave function after Kerr interaction is obtained analytically for an arbitrary photon number. The wave function is composed of two fundamental functions: the input mode function and the linear response function. The nonlinear effects appearing in this wave function are evaluated quantitatively, revealing the limitations of nonlinear quantum optics theories based on single-mode approximations.

  13. Meson wave function from holographic approaches

    SciTech Connect

    Vega, Alfredo; Schmidt, Ivan [Departamento de Fisica y Centro de Estudios Subatomicos, Universidad Tecnica Federico Santa Maria, Casilla 110-V, Valparaiso (Chile); Branz, Tanja; Gutsche, Thomas; Lyubovitskij, Valery E. [Institut fuer Theoretische Physik, Universitaet Tuebingen, Kepler Center for Astro and Particle Physics, Auf der Morgenstelle 14, D-72076 Tuebingen (Germany)

    2010-08-04

    We discuss the light-front wave function for the valence quark state of mesons using the AdS/CFT correspondence. We consider two kinds of wave functions obtained in different holographic Soft-Wall approaches.

  14. FastFEM: Breaking Wave Impact on Ships Wave breaking and wave impact on maritime structures are difficult to model

    E-print Network

    Wirosoetisno, Djoko

    FastFEM: Breaking Wave Impact on Ships Wave breaking and wave impact on maritime structures on fast ships. Faster ships have become more important in recent years. These include pilot ships, supply ships to oil rigs, repair vessels for offshore wind farms, rescue vessels, and coast guard vessels

  15. Green's Functions of Wave Equations in

    NASA Astrophysics Data System (ADS)

    Deng, Shijin; Wang, Weike; Yu, Shih-Hsien

    2015-06-01

    We study the d'Alembert equation with a boundary. We introduce the notions of Rayleigh surface wave operators, delayed/advanced mirror images, wave recombinations, and wave cancellations. This allows us to obtain the complete and simple formula of the Green's functions for the wave equation with the presence of various boundary conditions. We are able to determine whether a Rayleigh surface wave is active or virtual, and study the lacunas of the wave equation in three dimensional with the presence of a boundary in the case of a virtual Rayleigh surface wave.

  16. Photon wave function and Zitterbewegung

    NASA Astrophysics Data System (ADS)

    Wang, Zhi-Yong; Xiong, Cai-Dong; Qiu, Qi

    2009-09-01

    In terms of a photon wave function corresponding to the (1,0)+(0,1) representation of the Lorentz group, the radiation and Coulomb fields within a source-free region can be described unitedly by a Lorentz-covariant Dirac-like equation. In our formalism, the relation between the positive- and negative-energy solutions of the Dirac-like equation corresponds to the duality between the electric and magnetic fields, rather than to the usual particle-antiparticle symmetry. The Zitterbewegung (ZB) of photons is studied via the momentum vector of the electromagnetic field, which shows that only in the presence of virtual longitudinal and scalar photons, the ZB motion of photons can occur, and its vector property is described by the polarization vectors of the electromagnetic field.

  17. Wave Impact Reduction of Planing Boats

    Microsoft Academic Search

    William S. Vorus; Richard A. Royce

    The 3-year research effort reported here was dedicated to conception and development of devices for reducing the wave impact shock inherent with high-speed planing craft operating in waves. The first two years focused on assembly of rational methodology for predicting the hydrodynamics of generalized cylinders dropped onto a calm water surface. The generalizations were for a range of cross-section shapes

  18. Impact of 'functional food'.

    PubMed

    Guesry, Pierre René

    2005-01-01

    'Functional Food' is not a new concept but it became more important recently due to the collapse of most social health system because 'Functional Foods' allow low cost prevention of numerous diseases. 'Functional Foods' are different from 'Neutraceuticals' which remain drug based with poor taste whereas 'Functional Foods' remain good food which could be consumed for years, but in addition have a disease prophylactic function. They are becoming particularly important for the prevention of food allergy in 'at risk' population, obesity, osteoporosis, cardiovascular diseases and particularly high blood pressure and atherosclerosis, but also for cancer prevention. The newest trend is that governments and health authorities allow food manufacturers to make health prevention related claims on mass media. PMID:15702590

  19. Modular matrices from universal wave-function overlaps in Gutzwiller-projected parton wave functions

    E-print Network

    Mei, Jia-Wei

    We implement the universal wave-function overlap (UWFO) method to extract modular S and T matrices for topological orders in Gutzwiller-projected parton wave functions (GPWFs). The modular S and T matrices generate a ...

  20. Stress Wave Source Characterization: Impact, Fracture, and Sliding Friction

    NASA Astrophysics Data System (ADS)

    McLaskey, Gregory Christofer

    Rapidly varying forces, such as those associated with impact, rapid crack propagation, and fault rupture, are sources of stress waves which propagate through a solid body. This dissertation investigates how properties of a stress wave source can be identified or constrained using measurements recorded at an array of sensor sites located far from the source. This methodology is often called the method of acoustic emission and is useful for structural health monitoring and the noninvasive study of material behavior such as friction and fracture. In this dissertation, laboratory measurements of 1--300 mm wavelength stress waves are obtained by means of piezoelectric sensors which detect high frequency (10 kHz--3MHz) motions of a specimen's surface, picometers to nanometers in amplitude. Then, stress wave source characterization techniques are used to study ball impact, drying shrinkage cracking in concrete, and the micromechanics of stick-slip friction of Poly(methyl methacrylate) (PMMA) and rock/rock interfaces. In order to quantitatively relate recorded signals obtained with an array of sensors to a particular stress wave source, wave propagation effects and sensor distortions must be accounted for. This is achieved by modeling the physics of wave propagation and transduction as linear transfer functions. Wave propagation effects are precisely modeled by an elastodynamic Green's function, sensor distortion is characterized by an instrument response function, and the stress wave source is represented with a force moment tensor. These transfer function models are verified though calibration experiments which employ two different mechanical calibration sources: ball impact and glass capillary fracture. The suitability of the ball impact source model, based on Hertzian contact theory, is experimentally validated for small (˜1 mm) balls impacting massive plates composed of four different materials: aluminum, steel, glass, and PMMA. Using this transfer function approach and the two mechanical calibration sources, four types of piezoelectric sensors were calibrated: three commercially available sensors and the Glaser-type conical piezoelectric sensor, which was developed in the Glaser laboratory. The distorting effects of each sensor are modeled using autoregressive-moving average (ARMA) models, and because vital phase information is robustly incorporated into these models, they are useful for simulating or removing sensor-induced distortions, so that a displacement time history can be retrieved from recorded signals. The Glaser-type sensor was found to be very well modeled as a unidirectional displacement sensor which detects stress wave disturbances down to about 1 picometer in amplitude. Finally, the merits of a fully calibrated experimental system are demonstrated in a study of stress wave sources arising from sliding friction, and the relationship between those sources and earthquakes. A laboratory friction apparatus was built for this work which allows the micro-mechanisms of friction to be studied with stress wave analysis. Using an array of 14 Glaser-type sensors, and precise models of wave propagation effects and the sensor distortions, the physical origins of the stress wave sources are explored. Force-time functions and focal mechanisms are determined for discrete events found amid the "noise" of friction. These localized events are interpreted to be the rupture of micrometer-sized contacts, known as asperities. By comparing stress wave sources from stick-slip experiments on plastic/plastic and rock/rock interfaces, systematic differences were found. The rock interface produces very rapid (<1 microsecond) implosive forces indicative of brittle asperity failure and fault gouge formation, while rupture on the plastic interface releases only shear force and produces a source more similar to earthquakes commonly recorded in the field. The difference between the mechanisms is attributed to the vast differences in the hardness and melting temperatures of the two materials, which affect the distribution of asp

  1. Stochastic Quantum Trajectories without a Wave Function

    E-print Network

    Jeroen C. Vink

    2015-03-16

    After summarizing three versions of trajectory-based quantum mechanics, it is argued that only the original formulation due to Bohm, which uses the Schr\\"odinger wave function to guide the particles, can be readily extended to particles with spin. To extend the two wave function-free formulations, it is argued that necessarily particle trajectories not only determine location, but also spin. Since spin values are discrete, it is natural to revert to a variation of Bohm's pilot wave formulation due originally to Bell. It is shown that within this formulation with stochastic quantum trajectories, a wave function free formulation can be obtained.

  2. Meson wave function from holographic models

    SciTech Connect

    Vega, Alfredo; Schmidt, Ivan [Departamento de Fisica y Centro de Estudios Subatomicos, Universidad Tecnica Federico Santa Maria, Casilla 110-V, Valparaiso (Chile); Branz, Tanja; Gutsche, Thomas; Lyubovitskij, Valery E. [Institut fuer Theoretische Physik, Universitaet Tuebingen, Kepler Center for Astro and Particle Physics, Auf der Morgenstelle 14, D-72076 Tuebingen (Germany)

    2009-09-01

    We consider the light-front wave function for the valence quark state of mesons using the AdS/CFT correspondence, as has been suggested by Brodsky and Teramond. Two kinds of wave functions, obtained in different holographic Soft-Wall models, are discussed.

  3. Modeling of Wave Impact Using a Pendulum System 

    E-print Network

    Nie, Chunyong

    2011-08-08

    For high speed vessels and offshore structures, wave impact, a main source of environmental loads, causes high local stresses and structural failure. However, the prediction of wave impact loads presents numerous challenges due to the complex nature...

  4. Wave functions for Hamiltonian Lattice Gauge Theory

    E-print Network

    Matteo Beccaria

    2000-03-21

    We study four dimensional SU(2) lattice gauge theory in the Hamiltonian formalism by Green's Function Monte Carlo methods. A trial ground state wave function is introduced to improve the configuration sampling and we discuss the interplay between its complexity and the simulation systematic errors. As a case study, we compare the leading strong coupling approximation and an improved 4 parameters wave function with 1X1 and 1X2 plaquette terms. Our numerical results favors the second option.

  5. Impact damage detection in composite panels using guided ultrasonic waves

    NASA Astrophysics Data System (ADS)

    Murat, Bibi Intan Suraya; Khalili, Pouyan; Fromme, Paul

    2014-02-01

    Composite materials such as carbon fiber reinforced panels offer many advantages for aerospace applications, e.g, good strength to weight ratio. However, impact during the operation and servicing of the aircraft can lead to barely visible and difficult to detect damage. Depending on the severity of the impact, fiber breakage or delaminations can be induced which reduce the functionality of the structure. Efficient structural health monitoring of such plate-like components can be achieved using guided ultrasonic waves propagating along the structure and covering critical areas. However, the guided wave propagation in such anisotropic and inhomogeneous materials needs to be understood from theory and verified experimentally to achieve sufficient coverage of the structure. Using noncontact laser interferometer measurements the guided wave propagation in carbon fiber reinforced panels was investigated experimentally. Good agreement with calculations using a full three-dimensional Finite Element (FE) model was achieved. Impact damage was induced in the composite panels and the guided wave scattering at the damage measured and quantified. Good agreement with predictions was found and barely visible impact damage in composite panels detected.

  6. The Wave Function and Quantum Reality

    E-print Network

    Shan Gao

    2011-08-04

    We investigate the meaning of the wave function by analyzing the mass and charge density distribution of a quantum system. According to protective measurement, a charged quantum system has mass and charge density proportional to the modulus square of its wave function. It is shown that the mass and charge density is not real but effective, and it is formed by the ergodic motion of a localized particle with the total mass and charge of the system. Moreover, it is argued that the ergodic motion is not continuous but discontinuous and random. This result suggests a new interpretation of the wave function, according to which the wave function is a description of random discontinuous motion of particles, and the modulus square of the wave function gives the probability density of the particles being in certain locations. It is shown that the suggested interpretation of the wave function disfavors the de Broglie-Bohm theory and the many-worlds interpretation but favors the dynamical collapse theories, and the random discontinuous motion of particles may provide an appropriate random source to collapse the wave function.

  7. Exponentially self-similar impact ionization waves

    SciTech Connect

    Kyuregyan, A. S., E-mail: ask@vei.r [All-Russia Institute of Electrical Engineering (Russian Federation)

    2010-04-15

    The existence of generalized self-similar solutions to the system of continuity and Poisson equations is analyzed for the problem of evolution of impact ionization waves (IIWs). It is shown that, for any physically reasonable electric-field dependence of the impact ionization coefficients, there exist only exponentially self-similar ('limiting') asymptotic solutions. These solutions describe IIWs whose spatial scales and propagation velocities increase exponentially with time. Conditions are found for the existence of plane, cylindrical, and spherical waves of this type; their structure is described; analytical relations between the key parameters are derived; and effects of recombination (or attachment) and tunnel ionization are analyzed. It is shown that these IIWs are intermediate asymptotics of numerical solutions to the corresponding Cauchy problems. The most important and interesting type of exponentially self-similar IIWs are streamers in a uniform electric field. The simplest comprehensive and explicit model describing their evolution is a spherical IIW.

  8. Wave functions for hierarchical quantum Hall states

    NASA Astrophysics Data System (ADS)

    Suorsa, Juha; Hansson, Hans; Viefers, Susanne

    2010-03-01

    We propose a framework for obtaining microscopic representative wave functions which reflect Wen and Zee's classification of Abelian quantum Hall states. Explicit wave functions are related to coherent state transforms of combinations of chiral and antichiral blocks in simple conformal field theories. The approach reproduces all positive and negative Jain states as special cases, and also encompasses hierarchical states which involve condensates of both quasiholes and quasielectrons. We show that the proposed wave functions reduce to the known ground states in the thin cylinder limit.

  9. Spatial wave functions of photon and electron

    NASA Astrophysics Data System (ADS)

    Khokhlov, D. L.

    2010-12-01

    The quantum mechanical model of the photon and electron is considered. The photon is conceived of as a particle moving with the speed of light which is accompanied by the wave function of the photon spreading out with an infinite speed. The wave function of the electron is introduced in terms of virtual photons tied to the electron. A description of electrostatic and magnetostatic interactions is given through the wave functions of electrons. The approach provides an explanation of the results of recent experiments measuring the speed of propagation of the bound magnetic field.

  10. Sculpturing the Electron Wave Function

    E-print Network

    Shiloh, Roy; Lilach, Yigal; Arie, Ady

    2014-01-01

    Coherent electrons such as those in electron microscopes, exhibit wave phenomena and may be described by the paraxial wave equation. In analogy to light-waves, governed by the same equation, these electrons share many of the fundamental traits and dynamics of photons. Today, spatial manipulation of electron beams is achieved mainly using electrostatic and magnetic fields. Other demonstrations include simple phase-plates and holographic masks based on binary diffraction gratings. Altering the spatial profile of the beam may be proven useful in many fields incorporating phase microscopy, electron holography, and electron-matter interactions. These methods, however, are fundamentally limited due to energy distribution to undesired diffraction orders as well as by their binary construction. Here we present a new method in electron-optics for arbitrarily shaping of electron beams, by precisely controlling an engineered pattern of thicknesses on a thin-membrane, thereby molding the spatial phase of the electron wav...

  11. Wave functions for fractional Chern insulators

    E-print Network

    McGreevy, John

    We provide a parton construction of wave functions and effective field theories for fractional Chern insulators. We also analyze a strong-coupling expansion in lattice gauge theory that enables us to reliably map the parton ...

  12. On single nucleon wave functions in nuclei

    SciTech Connect

    Talmi, Igal [Weizamnn Institute of Science, Rehovot 76100 (Israel)

    2011-05-06

    The strong and singular interaction between nucleons, makes the nuclear many body theory very complicated. Still, nuclei exhibit simple and regular features which are simply described by the shell model. Wave functions of individual nucleons may be considered just as model wave functions which bear little resemblance to the real ones. There is, however, experimental evidence for the reality of single nucleon wave functions. There is a simple method of constructing such wave functions for valence nucleons. It is shown that this method can be improved by considering the polarization of the core by the valence nucleon. This gives rise to some rearrangement energy which affects the single valence nucleon energy within the nucleus.

  13. The geometry of electron wave functions

    SciTech Connect

    Aminov, Yurii A [B.Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, Khar'kov (Ukraine)] [B.Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, Khar'kov (Ukraine)

    2013-02-28

    To each wave function we assign a codimension-two submanifold in Euclidean space. We study the case of the wave function of a single electron in the hydrogen atom or other hydrogen-type atoms with quantum numbers n, l, m in detail. We prove theorems describing the behaviour of the scalar and sectional curvature of the constructed submanifold, depending on the quantum numbers. We also consider the external geometry of the submanifold. Bibliography: 9 titles.

  14. Interferometric measurement of the biphoton wave function

    E-print Network

    Federica A. Beduini; Joanna A. Zieli?ska; Vito G. Lucivero; Yannick A. de Icaza Astiz; Morgan W. Mitchell

    2014-07-29

    Interference between an unknown two-photon state (a "biphoton") and the two-photon component of a reference state gives a phase-sensitive arrival-time distribution containing full information about the biphoton temporal wave function. Using a coherent state as a reference, we observe this interference and reconstruct the wave function of single-mode biphotons from a low-intensity narrowband squeezed vacuum state.

  15. Improved wave functions for quantum Monte Carlo

    E-print Network

    Seth, Priyanka

    2013-02-05

    similarity- transformed Hamiltonian HTC is not Hermitian. Consequently, interest in the method faded. Following a recent revival, the transcorrelated method has been applied to a variety of systems including solids [15], for which traditional quantum... The antisymmetry of fermionic wave functions requires that they have both positive and negative regions, preventing the wave function from being directly interpreted as a prob- ability distribution. This fundamental property is at the root of the fermion sign...

  16. Noncommuting limits of oscillator wave functions

    NASA Astrophysics Data System (ADS)

    Daboul, J.; Pogosyan, G. S.; Wolf, K. B.

    2007-03-01

    Quantum harmonic oscillators with spring constants k > 0 plus constant forces f exhibit rescaled and displaced Hermite—Gaussian wave functions, and discrete, lower bound spectra. We examine their limits when (k, f) ? (0, 0) along two different paths. When f ? 0 and then k ? 0, the contraction is standard: the system becomes free with a double continuous, positive spectrum, and the wave functions limit to plane waves of definite parity. On the other hand, when k ? 0 first, the contraction path passes through the free-fall system, with a continuous, nondegenerate, unbounded spectrum and displaced Airy wave functions, while parity is lost. The subsequent f ? 0 limit of the nonstandard path shows the dc hysteresis phenomenon of noncommuting contractions: the lost parity reappears as an infinitely oscillating superposition of the two limiting solutions that are related by the symmetry.

  17. The Wave Function and Quantum Reality

    SciTech Connect

    Gao Shan [Unit for History and Philosophy of Science and Centre for Time, SOPHI, University of Sydney, Sydney, NSW 2006 (Australia)

    2011-03-28

    We investigate the meaning of the wave function by analyzing the mass and charge density distributions of a quantum system. According to protective measurement, a charged quantum system has effective mass and charge density distributing in space, proportional to the square of the absolute value of its wave function. In a realistic interpretation, the wave function of a quantum system can be taken as a description of either a physical field or the ergodic motion of a particle. The essential difference between a field and the ergodic motion of a particle lies in the property of simultaneity; a field exists throughout space simultaneously, whereas the ergodic motion of a particle exists throughout space in a time-divided way. If the wave function is a physical field, then the mass and charge density will be distributed in space simultaneously for a charged quantum system, and thus there will exist gravitational and electrostatic self-interactions of its wave function. This not only violates the superposition principle of quantum mechanics but also contradicts experimental observations. Thus the wave function cannot be a description of a physical field but be a description of the ergodic motion of a particle. For the later there is only a localized particle with mass and charge at every instant, and thus there will not exist any self-interaction for the wave function. It is further argued that the classical ergodic models, which assume continuous motion of particles, cannot be consistent with quantum mechanics. Based on the negative result, we suggest that the wave function is a description of the quantum motion of particles, which is random and discontinuous in nature. On this interpretation, the square of the absolute value of the wave function not only gives the probability of the particle being found in certain locations, but also gives the probability of the particle being there. The suggested new interpretation of the wave function provides a natural realistic alternative to the orthodox interpretation, and it also implies that the de Broglie-Bohm theory and many-worlds interpretation are wrong and the dynamical collapse theories are in the right direction by admitting wavefunction collapse.

  18. Weak Measurement and (Bohmian) Conditional Wave Functions

    E-print Network

    Travis Norsen; Ward Struyve

    2013-10-07

    It was recently pointed out (and demonstrated experimentally) by Lundeen et al. that the wave function of a particle (more precisely, the wave function possessed by each member of an ensemble of identically-prepared particles) can be "directly measured" using weak measurement. Here it is shown that if this same technique is applied, with appropriate post-selection, to one particle from a (perhaps entangled) multi-particle system, the result is precisely the so-called "conditional wave function" of Bohmian mechanics. Thus, a plausibly operationalist method for defining the wave function of a quantum mechanical sub-system corresponds to the natural definition of a sub-system wave function which Bohmian mechanics (uniquely) makes possible. Similarly, a weak-measurement-based procedure for directly measuring a sub-system's density matrix should yield, under appropriate circumstances, the Bohmian "conditional density matrix" as opposed to the standard reduced density matrix. Experimental arrangements to demonstrate this behavior -- and also thereby reveal the non-local dependence of sub-system state functions on distant interventions -- are suggested and discussed.

  19. Functional methods for waves in random media

    NASA Technical Reports Server (NTRS)

    Chow, P. L.

    1981-01-01

    Some basic ideas in functional methods for waves in random media are illustrated through a simple random differential equation. These methods are then generalized to solve certain random parabolic equations via an exponential representation given by the Feynman-Kac formula. It is shown that these functional methods are applicable to a number of problems in random wave propagation. They include the forward-scattering approximation in Gaussian white-noise media; the solution of the optical beam propagation problem by a phase-integral method; the high-frequency scattering by bounded random media, and a derivation of approximate moment equations from the functional integral representation.

  20. Measurement of Oblique Impact-generated Shear Waves

    NASA Technical Reports Server (NTRS)

    Dahl, J. M.; Schultz, P. H.

    2001-01-01

    Experimental strain measurements reveal that oblique impacts can generate shear waves with displacements as large as those in the P-wave. Large oblique impacts may thus be more efficient sources of surface disruption than vertical impacts. Additional information is contained in the original extended abstract.

  1. Mass criterion for wave controlled impact response of composite plates

    Microsoft Academic Search

    R. Olsson

    2000-01-01

    Impact duration strongly influences the impact response of plates. Long impacts cause a quasi-static response influenced by the plate size and boundary conditions. Short impacts cause a response governed by wave propagation unaffected of plate size and boundary conditions. This paper shows that the response type is governed by the impactor–plate mass ratio and not by impact velocity and derives

  2. Impact Seismology: A Search for Primary Pressure Waves Following Impacts A and H

    NASA Astrophysics Data System (ADS)

    Mosser, B.; Galdemard, P.; Lagage, P.; Pantin, E.; Sauvage, M.; Lognonné, P.; Gautier, D.; Billebaud, F.; Livengood, T.; Käufl, H. U.

    1996-06-01

    This paper reports part of the seismic observations performed after the impacts of Shoemaker-Levy 9 fragments A and H with the mid-IR camera TIMMI at the ESO 3.6-m telescope. Hodograms have been computed to search for the seismic signature of the primary waves crossing the planet within 2 hr following each impact. The hodogram analysis has been unable to detect any seismic signal. In order to put a limit on the kinetic energy of the fragments, the synthetic thermal signature of the primary wave has been calculated as a function of the incident energy, according to theoretical simulations, and taking into account observational conditions such as the point spread function. The non-detection implies that the kinetic energy of impacts A and H was less than 2 × 1021J, within the frame of the theoretical simulation of Lognonnéet al.(Lognonné, Ph., B. Mosser, and F. Dahlen 1994.Icarus110, 180-195.). The error bar is as large as one order of magnitude, according to other simulations. The seismic wave should have contributed to a non-negligible part of the heating of the region surrounding the impacts, but it is not yet possible to measure its contribution.

  3. Does consciousness really collapse the wave function?

    Microsoft Academic Search

    Fred H. Thaheld

    2005-01-01

    An analysis has been performed of the theories and postulates advanced by von Neumann, London and Bauer, and Wigner, concerning the role that consciousness might play in the collapse of the wave function, which has become known as the measurement problem. This reveals that an error may have been made by them in the area of biology and its interface

  4. Impact damage detection in composite structures using Lamb waves

    Microsoft Academic Search

    Ajit K. Mal; Frank J. Shih; Fabrizio Ricci; Sauvik Banerjee

    2005-01-01

    This paper is concerned with the detection of low velocity impact and the associated internal damage in composite structures using Lamb waves. Impact tests are carried out on a cross ply graphite epoxy plate using an instrumented impact testing system. The contact force and the surface motion caused by the impact load are recorded at several points on the plate

  5. Breaking wave impact pressures on a vertical wall

    NASA Astrophysics Data System (ADS)

    Sannasi A., S.; Naik, M. S.

    2009-04-01

    The growing concern for the proper utilization of the coastal zone resulted in increased efforts by researchers in understanding the coastal zone dynamics. The wall type structures are widely adopted by coastal engineers for the purpose of breakwaters and coastal protection works. These structures are designed to withstand the environmental loads due to waves, tides and currents. The interaction of these loads and their variability makes design of these structures more complex. These vertical walls are at times subjected to severe wave loads, the worst being those caused by breaking wave impact. Impact forces can be two to four times larger than the non-impact forces even though the incident wave amplitudes are comparable. Also, within the region of wave impact, pressures can be ten to fifteen times larger than the non impact pressures. Such impulse wave loads can easily lead to local fatigue problems and even local damage. It is clear that a good understanding of wave impact on structures is also important for offshore engineers. In the present study, the imparted pressures resulting from a single plunging wave impact on a vertical wall is studied through laboratory experiments. The experiments were conducted in the 30m long current cum wave flume of the Department of Ocean Engineering, I.I.T-Madras. The flume is 2m wide and 1.0m deep. A water depth of 0.8m was adopted for the experiments. The vertical wall, of size 2m wide and 1.2m high, was fabricated using a fiber board of 10mm thickness and supported by a mild steel angle frame. Wave plunging was simulated through the frequency modulated wave packet. The non-dimensionalized peak impact pressure, P/Cc2 has been measured in the range of 0.104 to 0.316 for various relative position of vertical wall with respect to the point of wave breaking in a narrower range, x/xb of 0.982 to 1.025, where xb is the point of wave breaking where the wave attains maximum steepness. The duration of wave impact , t / Tc ranges from 17.45 to 17.73. The maximum impact pressure was observed to occur above the still water level, z/d at 0.12 to 0.18. The duration during which the maximum impulse pressure occurred was estimated to be less than 0.01Tc .The breaking wave impact pressures were found to be 10 to 15 times more than the non-breaking wave dynamic pressures.

  6. Source Field Effects and Wave Function Collapse

    E-print Network

    Atilla Gurel; Zeynep Gurel

    2004-03-16

    Detection of a material particle is accompanied by emission of bremsstrahlung. Thus the dynamics of the energy loss of the particle is determined by radiation reaction force. The description of radiation reaction is a difficult problem still being subject of ongoing debates. There are problems of runaway solutions, preacceleration already in classical description of radiation reaction. Additional complications in quantum mechanical description arise because of the infinite source field energy term in hamiltonian for a point charge. There is still no general consensus on an appropriate quantum mechanical description. Neither the achievements of the radiation theory on the subject nor the problems associated with it are sufficiently taken into account in context with measurement problem. Radiation reaction doesn't effect free particle wave packets, but it favors stationary states of the `wave function of the measured particle" in presence of a potential gradient. We suggest therefore that radiation reaction may play a significant role in the dynamics of the wave function collapse. keywords: wave function collapse,interpretation,randomness, Jaynes Cummings dynamics, spontaneous emission, source field effects, radiation reaction, quantum measurement,decoherence

  7. Impact detection using ultrasonic waves based on artificial immune system

    NASA Astrophysics Data System (ADS)

    Okamoto, Keisuke; Mita, Akira

    2009-03-01

    This paper presents a structural health monitoring system for judging structural condition of metallic plates by analyzing ultrasonic waves. Many critical accidents of structures like buildings and aircrafts are caused by small structural errors; cracks and loosened bolts etc. This is a reason why we need to detect little errors at an early stage. Moreover, to improve precision and to reduce cost for damage detection, it is necessary to build and update the database corresponding to environmental change. This study focuses our attention on the automatable structures, specifically, applying artificial immune system (AIS) algorithm to determine the structure safe or not. The AIS is a novelty computational detection algorithm inspired from biological defense system, which discriminates between self and non-self to reject nonself cells. Here, self is defined to be normal data patterns and non-self is abnormal data patterns. Furthermore, it is not only pattern recognition but also it has a storage function. In this study, a number of impact resistance experiments of duralumin plates, with normal structural condition and abnormal structural condition, are examined and ultrasonic waves are acquired by AE sensors on the surface of the aluminum plates. By accumulating several feature vectors of ultrasonic waves, a judging method, which can determine an abnormal wave as nonself, inspired from immune system is created. The results of the experiments show good performance of this method.

  8. Wave function methods for fractional electrons

    NASA Astrophysics Data System (ADS)

    Steinmann, Stephan N.; Yang, Weitao

    2013-08-01

    Determining accurate chemical potentials is of considerable interest in various chemical and physical contexts: from small molecular charge-transfer complexes to bandgap in bulk materials such as semi-conductors. Chemical potentials are typically evaluated either by density functional theory, or, alternatively, by computationally more intensive Greens function based GW computations. To calculate chemical potentials, the ground state energy needs to be defined for fractional charges. We thus explore an extension of wave function theories to fractional charges, and investigate the ionization potential and electron affinity as the derivatives of the energy with respect to the electron number. The ultimate aim is to access the chemical potential of correlated wave function methods without the need of explicitly changing the numbers of electrons, making the approach readily applicable to bulk materials. We find that even though second order perturbation theory reduces the fractional charge error considerably compared to Hartree-Fock and standard density functionals, higher order perturbation theory is more accurate and coupled-cluster approaches are even more robust, provided the electrons are bound at the Hartree-Fock level. The success of post-HF approaches to improve over HF relies on two equally important aspects: the integer values are more accurate and the Coulomb correlation between the fractionally occupied orbital and all others improves the straight line behavior significantly as identified by a correction to Hartree-Fock. Our description of fractional electrons is also applicable to fractional spins, illustrating the ability of coupled-cluster singles and doubles to deal with two degenerate fractionally occupied orbitals, but its inadequacy for three and more fractional spins, which occur, for instance, for spherical atoms and when dissociating double bonds. Our approach explores the realm of typical wave function methods that are applied mostly in molecular chemistry, but become available to the solid state community and offer the advantage of an integrated approach: fundamental gap, relative energies, and optimal geometries can be obtained at the same level.

  9. Love wave propagation in functionally graded piezoelectric material layer

    E-print Network

    Wang, Ji

    Love wave propagation in functionally graded piezoelectric material layer Jianke Du *, Xiaoying Jin is used to investigate Love waves in functionally graded piezoelectric material (FGPM) layer bonded. Numerical examples indicate that appropriate gradient distributing of the material properties make Love

  10. Impact of Functionally Graded Cylinders: Theory

    NASA Technical Reports Server (NTRS)

    Aboudi, Jacob; Pindera, Marek-Jerzy; Arnold, S. M. (Technical Monitor)

    2001-01-01

    This final report summarizes the work funded under the Grant NAG3-2411 during the 04/05/2000-04/04/2001 period. The objective of this one-year project was to generalize the theoretical framework of the two-dimensional higher-order theory for the analysis of cylindrical functionally graded materials/structural components employed in advanced aircraft engines developed under past NASA Glenn funding. The completed generalization significantly broadens the theory's range of applicability through the incorporation of dynamic impact loading capability into its framework. Thus, it makes possible the assessment of the effect of damage due to fuel impurities, or the presence of submicron-level debris, on the life of functionally graded structural components. Applications involving advanced turbine blades and structural components for the reusable-launch vehicle (RLV) currently under development will benefit from the completed work. The theory's predictive capability is demonstrated through a numerical simulation of a one-dimensional wave propagation set up by an impulse load in a layered half-plane. Full benefit of the completed generalization of the higher-order theory described in this report will be realized upon the development of a related computer code.

  11. Can We Measure the Wave Function of a SingleWave Packet of Light?

    E-print Network

    Utah, University of

    Can We Measure the Wave Function of a SingleWave Packet of Light? Brownian Motion and Continuous Wave Packet Collapse in RepeatedWeak Quantum Nondemolition Measurements ORLY ALTER AND YOSHIHISA, the wave function of the measured system collapses to the corresponding eigenstate, according

  12. Impact of shear and curvature on surface gravity wave stress

    NASA Astrophysics Data System (ADS)

    Miranda, P. M. A.; Martins, J. P. A.; Teixeira, M. A. C.

    2009-09-01

    It has been shown that surface gravity wave stress is sensitive to the low level wind profile shape. The simplest way of incorporating those effects in a theoretical model has been recently proposed, using a second order WKB approach, which leads to closed analytical formulae for the surface stress as a function of stability, low level wind and its two first derivatives (shear and curvature). In the present study, we assess the impact of those calculations on global scale gravity wave stress and the corresponding torque, using 6-hourly data from ERA-40 reanalysis, at full resolution. While the theory shows that linear wind shear leads to a reduced stress and curvature may lead to stress enhancement, the present results indicate that the latter effect is dominant. However, when one looks for regionally integrated stress fields for the large mountain ranges, where cancellation effects take place thorough time and space integration, the overall effect is one of drag enhancement in regions of dominant easterly flow, namely Antarctica and East Africa, leading to a slight reduction of the global westerly torque due to mountain waves. Drag enhancement due to wind profile curvature seems to be an important effect in Antarctic flow, where it accounts for a 50% increase in the mean regional torque, with implied consequences for the dynamics of the polar vortex.

  13. Lee-Yang measures and wave functions

    E-print Network

    Dimitar K. Dimitrov

    2013-11-04

    We establish necessary and sufficient conditions for a Borel measure to be a Lee-Yang one which means that its Fourier transform possesses only real zeros. Equivalently, we answer a question of P\\'olya who asked for a characterisation of those positive positive, even and sufficiently fast decaying kernels whose Fourier transforms have only real zeros. The characterisation is given in terms of Wronskians of polynomials that are orthogonal with respect to the measure. The results show that Fourier transforms of a rather general class of measures can be approximated by symmetrized Slater determinants composed by orthogonal polynomials, that is, by some wave functions which are symmetric like the Boson ones. Brief comments on possible interpretation and applications of the main results in quantum and statistical mechanics, to Toda lattices and the general solution of the heat equation, are given. We discuss briefly the possibility of represent the Riemann $\\xi$ function as a partition function of a statistical mechanics system.

  14. Wave energy converters and their impact on power systems

    Microsoft Academic Search

    Henk Polinder; Mattia Scuotto

    2005-01-01

    The objective of this paper is to give an introduction into ocean wave energy converters and their impact on power systems. The potential of wave energy is very large. There are a lot of different methods and systems for converting this power into electrical power, such as oscillating water columns, hinged contour devices as the Pelamis, overtopping devices as the

  15. Wave functions of log-periodic oscillators

    SciTech Connect

    Bessa, V.; Guedes, I. [Departamento de Fisica, Universidade Federal do Ceara, Campus do Pici, Fortaleza, CE 60455-760 (Brazil)

    2011-06-15

    We use the Lewis and Riesenfeld invariant method [J. Math. Phys. 10, 1458 (1969)] and a unitary transformation to obtain the exact Schroedinger wave functions for time-dependent harmonic oscillators exhibiting log-periodic-type behavior. For each oscillator we calculate the quantum fluctuations in the coordinate and momentum as well as the quantum correlations between the coordinate and momentum. We observe that the oscillator with m=m{sub 0}t/t{sub 0} and {omega}={omega}{sub 0}t{sub 0}/t, which exhibits an exact log-periodic oscillation, behaves as the harmonic oscillator with m and {omega} constant.

  16. Why the wave function, of all things?

    E-print Network

    Ulrich Mohrhoff

    2014-11-05

    There are reasons to doubt that making sense of the wave function (other than as a probability algorithm) will help with the project of making sense of quantum mechanics. The consistency of the quantum-mechanical correlation laws with the existence of their correlata is demonstrated. The demonstration makes use of the fact (which is implied by the indeterminacy principle) that physical space is not partitioned "all the way down," and it requires that the eigenvalue-eigenstate link be replaced by a different interpretive principle, whose implications are explored.

  17. POINTWISE GREEN FUNCTION BOUNDS AND STABILITY OF COMBUSTION WAVES

    E-print Network

    Texier, Benjamin - Institut de Mathématiques de Jussieu, Université Paris 7

    POINTWISE GREEN FUNCTION BOUNDS AND STABILITY OF COMBUSTION WAVES GREGORY LYNG, MOHAMMADREZA ROOFI for traveling wave solutions of an abstract viscous combustion model including both Majda's model and the full-wave) approximation. Notably, our results apply to combustion waves of any type: weak or strong, detonations or defla

  18. Extreme waves impact on the ship mooring near berth

    NASA Astrophysics Data System (ADS)

    Leont'ev, Victor; Nudner, Igor; Semenov, Konstantin; Pelinovsky, Efim

    2013-04-01

    Ensuring safe ships berthing and loading-unloading operations at berths need reliable mooring systems. The choice of its parameters corresponds to calculating of the maximum displacements of the boat, which are caused by external impact of extreme waves, winds, and currents. Ship motions are described by system of differential equations, which contain disturbing, inertia, damping, and restoring forces, which magnitude strongly depends on the berth design and configuration of its elements. The major impact on the boat movements is caused by sea waves. In the given paper, an interaction between sea waves and ship located near the berth is studied. The cross-sectional shape of the boat is assumed to be rectangular and under-berth slope profile is approximated by finite number of steps. Different types of berth constructions are taken into account: containing impermeable or partially permeable front vertical wall, wave attenuation camera behind it with or without under-berth slope. The fluid is assumed ideal and incompressible, and its motion is potential. The stated problem is reduced to the determination of the velocity potential that satisfies the Laplace equation; the boundary condition on the free surface; the condition of non-flux through the impermeable bottom, the ship and berth elements; the condition on the surface of the permeable wall that is in proportionality between the wave flow velocity through the wall and pressure drop from its front to back faces. The problem is solved by dividing of the region into sub-domains with conditions of the hydrodynamic pressure and velocity continuity on its boundaries. In each sub-domain the solution is found using Fourier method in the form of functional series with unknown coefficients which are found from the system of linear algebraic equations. Calculated velocity potentials are used to determine different hydrodynamic characteristics of ship motions, such as horizontal and vertical components of disturbing force and moment, added masses and damping coefficients for all types of boat motions. The results of calculations are presented and they are compared with experimental data performed by authors.

  19. Physical meaning of the photon wave function

    NASA Astrophysics Data System (ADS)

    Inagaki, Toshio

    1998-03-01

    Recently, the author [Phys. Rev. A 49, 2839 (1994)] proposed a quantum-mechanical theory of a photon, in which negative energy states can be dismissed from physical photon states without causing any difficulties. In this Brief Report the physical meaning of a photon wave function is investigated more precisely. The interpretation of a photon wave function as a probability amplitude is guaranteed by requiring the coarse-grained condition that the linear dimensions of a volume or a surface concerned in the configuration space are large compared to the photon wavelengths. The calculation made here is essentially based on that presented by Mandel [Phys. Rev. 144, 1071 (1966)] in his analysis of the photon number operator. But our calculation includes that of Mandel as the zeroth-order approximation. As a result, it is shown that although the position operator x⁁ in the ordinary quantum mechanics be considered a correct photon operator strictly cannot, it becomes meaningful to some extent under the coarse-grained condition. In connection with x⁁, we also examine the velocity operator [x⁁,H⁁]/i? (H⁁ is the photon Hamiltonian), and show that the probability current density is definable under the coarse-grained condition.

  20. Localized Single-Photon Wave Functions in Free Space

    NASA Astrophysics Data System (ADS)

    Chan, K. W.; Law, C. K.; Eberly, J. H.

    2002-03-01

    We solve the joint open problems of photon localization and single-photon wave functions in the context of spontaneous emission from an excited atom in free space. Our wave functions are well-defined members of a discrete orthonormal function set. Both the degree and shape of the localization are controlled by entanglement mapping onto the atom wave function, even though the atom is remote from the photon.

  1. Climate impact response functions for terrestrial ecosystems

    Microsoft Academic Search

    Hans-Martin Füssel; Jelle G. van Minnenb

    2001-01-01

    We introduce climate impact response functions as a means for summarizing and visualizing the responses of climate-sensitive sectors to changes in fundamental drivers of global climate change. In an inverse application, they allow the translation of thresholds for climate change impacts ('impact guard-rails') into constraints for climate and atmospheric composition parameters ('climate windows'). It thus becomes feasible to specify long-term

  2. Climate Impact Response Functions for Terrestrial Ecosystems

    Microsoft Academic Search

    Hans-Martin Füssel; Jelle G. van Minnen

    2001-01-01

    We introduce climate impact response functions as a means for summarizing and visualizing the responses of climate-sensitive\\u000a sectors to changes in fundamental drivers of global climate change. In an inverse application, they allow the translation\\u000a of thresholds for climate change impacts (‘impact guard-rails’) into constraints for climate and atmospheric composition parameters\\u000a (‘climate windows’). It thus becomes feasible to specify long-term

  3. Guided ultrasonic waves for impact damage detection in composite panels

    NASA Astrophysics Data System (ADS)

    Murat, B. I. S.; Khalili, P.; Fromme, P.

    2014-03-01

    Carbon fiber laminate composites, consisting of layers of polymer matrix reinforced with high strength carbon fibers, are increasingly employed for aerospace structures. They offer advantages for aerospace applications, e.g., good strength to weight ratio. However, impact during the operation and servicing of the aircraft can lead to barely visible and difficult to detect damage. Depending on the severity of the impact, fiber and matrix breakage or delaminations can occur, reducing the load carrying capacity of the structure. Efficient structural health monitoring of composite panels can be achieved using guided ultrasonic waves propagating along the structure. Impact damage was induced in the composite panels using standard drop weight procedures. The guided wave scattering at the impact damage was measured using a noncontact laser interferometer, quantified, and compared to baseline measurements on undamaged composite panels. Significant scattering of the first anti-symmetrical (A0) guided wave mode was observed, allowing for the detection of barely visible impact damage. The guided wave scattering was modeled using full three-dimensional Finite Element (FE) simulations, and the influence of the different damage mechanisms investigated. Good agreement between experiments and predictions was found. The sensitivity of guided waves for the detection of barely visible impact damage in composite panels has been verified.

  4. Impact friction test method by applying stress wave

    Microsoft Academic Search

    K. Ogawa

    1997-01-01

    To understand the dynamic response of two bodies in contact, kinetic friction during impact presently is focused on. A new\\u000a testing technique, which provides the normal and the tangential impact force independently, is developed by modifying the\\u000a split Hopkinson pressure bar method. Normal and torsional stress wave propagation in a one-dimensional framework of an axial\\u000a impact of an input tube

  5. String wave function across a Kasner singularity

    SciTech Connect

    Copeland, Edmund J.; Niz, Gustavo [School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Turok, Neil [Perimeter Institute for Theoretical Physics, 31 Caroline Street N, Waterloo, Ontario N2L2Y5 (Canada)

    2010-06-15

    A collision of orbifold planes in 11 dimensions has been proposed as an explanation of the hot big bang. When the two planes are close to each other, the winding membranes become the lightest modes of the theory, and can be effectively described in terms of fundamental strings in a ten-dimensional background. Near the brane collision, the 11-dimensional metric is a Euclidean space times a 1+1-dimensional Milne universe. However, one may expect small perturbations to lead into a more general Kasner background. In this paper we extend the previous classical analysis of winding membranes to Kasner backgrounds, and using the Hamiltonian equations, solve for the wave function of loops with circular symmetry. The evolution across the singularity is regular, and explained in terms of the excitement of higher oscillation modes. We also show there is finite particle production and unitarity is preserved.

  6. Fermi-hypernetted-chain scheme for Gutzwiller correlated wave functions

    NASA Astrophysics Data System (ADS)

    Wang, X. Q. G.; Fantoni, S.; Tosatti, E.; Yu, L.

    1994-04-01

    A set of integral equations in the Fermi-hypernetted-chain scheme is formulated for Gutzwiller correlated wave functions. The well-known exact analytical results of Vollhardt, Metzner, and Gebhard for the one- and infinite-dimensional Gutzwiller paramagnetic wave functions are recovered as a byproduct of the theory. In approximate form, the theory is applicable to arbitrary Gutzwiller correlated wave functions, irrespective of the space dimensionality of the model.

  7. A new FHNC scheme for Gutzwiller correlated wave functions

    NASA Astrophysics Data System (ADS)

    Wang, X. Q. G.; Fantoni, S.; Tosatti, E.; Yu, L.

    1993-11-01

    A new set of integral equations in Fermi Hyper-Netted Chain scheme, named GHNC is formulated for Gutzwiller correlated wave functions. The well-known exact analytical results of Vollhardt, Metzner and Gebhard for the one and infinite dimension Gutzwiller paramagnetic wave functions are recovered as a byproduct of the theory. In approximate form, the theory is applicable to arbitrary Gutzwiller correlated wave functions, irrespective of the space dimensionality of the model.

  8. Protective measurements of the wave function of a single system

    E-print Network

    Lev Vaidman

    2014-02-27

    My view on the meaning of the quantum wave function and its connection to protective measurements is described. The wave function and only the wave function is the ontology of the quantum theory. Protective measurements support this view although they do not provide a decisive proof. A brief review of the discovery and the criticism of protective measurements is presented. Protective measurements with postselection are discussed.

  9. POSSIBLE EXPERIMENTS ON WAVE FUNCTION LOCALIZATION DUE TO COMPTON SCATTERING

    SciTech Connect

    Aleksandrov, Alexander V [ORNL] [ORNL; Danilov, Viatcheslav V [ORNL] [ORNL; Gorlov, Timofey V [ORNL] [ORNL; Liu, Yun [ORNL] [ORNL; Shishlo, Andrei P [ORNL] [ORNL; Nagaitsev, [FNAL] [FNAL

    2013-01-01

    The reduction of a particle s wave function in the process of radiation or light scattering is a longstanding problem. Its solution will give a clue on processes that form, for example, wave functions of electrons constantly emitting synchrotron radiation quanta in storage rings. On a more global scale, it may shed light on wave function collapse due to the process of measurement. In this paper we consider various experimental options using Fermilab electron beams and a possible electron beam from the SNS linac and lasers to detect electron wave function change due to Compton scattering.

  10. Theory of stationary impact-ionization plane waves in semiconductors

    SciTech Connect

    Kyuregyan, A. S. [All-Russia Electrical Engineering Institute (Russian Federation)], E-mail: ask@vei.ru

    2007-06-15

    General analytical theory of stationary impact-ionization plane waves in semiconductor devices with arbitrary electric-field dependence of drift velocities and impact-ionization coefficients of electrons and holes is developed. The formulas are obtained that describe the structure of the wave front and make it possible to calculate its main parameters (velocity, width, maximum electric field, concentration of charge carriers, and electric field behind the front) for given values of current density and doping level of the semiconductor. Limitations of the theory resulting from the disregard of the diffusion current and continuum approximation are considered.

  11. Shock Waves Impacting Composite Material Plates: The Mutual Interaction

    NASA Astrophysics Data System (ADS)

    Andreopoulos, Yiannis

    2013-02-01

    High-performance, fiber-reinforced polymer composites have been extensively used in structural applications in the last 30 years because of their light weight combined with high specific stiffness and strength at a rather low cost. The automotive industry has adopted these materials in new designs of lightweight vehicles. The mechanical response and characterization of such materials under transient dynamic loading caused with shock impact induced by blast is not well understood. Air blast is associated with a fast traveling shock front with high pressure across followed by a decrease in pressure behind due to expansion waves. The time scales associated with the shock front are typically 103 faster than those involved in the expansion waves. Impingement of blast waves on structures can cause a reflection of the wave off the surface of the structure followed by a substantial transient aerodynamic load, which can cause significant deformation and damage of the structure. These can alter the overpressure, which is built behind the reflected shock. In addition, a complex aeroelastic interaction between the blast wave and the structure develops that can induce reverberation within an enclosure, which can cause substantial overpressure through multiple reflections of the wave. Numerical simulations of such interactions are quite challenging. They usually require coupled solvers for the flow and the structure. The present contribution provides a physics-based analysis of the phenomena involved, a critical review of existing computational techniques together with some recent results involving face-on impact of shock waves on thin composite plates.

  12. Photon wave functions, wave-packet quantization of light, and coherence theory

    Microsoft Academic Search

    Brian J. Smith; M. G. Raymer

    2007-01-01

    The monochromatic Dirac and polychromatic Titulaer–Glauber quantized field theories (QFTs) of electromagnetism are derived from a photon-energy wave function in much the same way that one derives QFT for electrons, i.e., by quantization of a single-particle wave function. The photon wave function and its equation of motion are established from the Einstein energy–momentum–mass relation, assuming a local energy density. This

  13. Six Impossible Things: Fractional Charge From Laughlin's Wave Function

    SciTech Connect

    Shrivastava, Keshav N. [Department of Physics, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia)

    2010-12-23

    The Laughlin's wave function is found to be the zero-energy ground state of a {delta}-function Hamiltonian. The finite negative value of the ground state energy which is 91 per cent of Wigner value, can be obtained only when Coulomb correlations are introduced. The Laughlin's wave function is of short range and it overlaps with that of the exact wave functions of small (number of electrons 2 or 5) systems. (i) It is impossible to obtain fractional charge from Laughlin's wave function. (ii) It is impossible to prove that the Laughlin's wave function gives the ground state of the Coulomb Hamiltonian. (iii) It is impossible to have particle-hole symmetry in the Laughlin's wave function. (iv) It is impossible to derive the value of m in the Laughlin's wave function. The value of m in {psi}{sub m} can not be proved to be 3 or 5. (v) It is impossible to prove that the Laughlin's state is incompressible because the compressible states are also likely. (vi) It is impossible for the Laughlin's wave function to have spin. This effort is directed to explain the experimental data of quantum Hall effect in GaAs/AlGaAs.

  14. Photon wave functions, wave-packet quantization of light, and coherence theory

    NASA Astrophysics Data System (ADS)

    Smith, Brian J.; Raymer, M. G.

    2007-11-01

    The monochromatic Dirac and polychromatic Titulaer Glauber quantized field theories (QFTs) of electromagnetism are derived from a photon-energy wave function in much the same way that one derives QFT for electrons, i.e., by quantization of a single-particle wave function. The photon wave function and its equation of motion are established from the Einstein energy momentum mass relation, assuming a local energy density. This yields a theory of photon wave mechanics (PWM). The proper Lorentz-invariant single-photon scalar product is found to be non-local in coordinate space, and is shown to correspond to orthogonalization of the Titulaer Glauber wave-packet modes. The wave functions of PWM and mode functions of QFT are shown to be equivalent, evolving via identical equations of motion, and completely describe photonic states. We generalize PWM to two or more photons, and show how to switch between the PWM and QFT viewpoints. The second-order coherence tensors of classical coherence theory and the two-photon wave functions are shown to propagate equivalently. We give examples of beam-like states, which can be used as photon wave functions in PWM, or modes in QFT. We propose a practical mode converter based on spectral filtering to convert between wave packets and their corresponding biorthogonal dual wave packets.

  15. Photon wave functions, wave-packet quantization of light, and coherence theory

    E-print Network

    Brian J. Smith; M. G. Raymer

    2007-12-09

    The monochromatic Dirac and polychromatic Titulaer-Glauber quantized field theories (QFTs) of electromagnetism are derived from a photon-energy wave function in much the same way that one derives QFT for electrons, that is, by quantization of a single-particle wave function. The photon wave function and its equation of motion are established from the Einstein energy-momentum-mass relation, assuming a local energy density. This yields a theory of photon wave mechanics (PWM). The proper Lorentz-invariant single-photon scalar product is found to be non-local in coordinate space, and is shown to correspond to orthogonalization of the Titulaer-Glauber wave-packet modes. The wave functions of PWM and mode functions of QFT are shown to be equivalent, evolving via identical equations of motion, and completely describe photonic states. We generalize PWM to two or more photons, and show how to switch between the PWM and QFT viewpoints. The second-order coherence tensors of classical coherence theory and the two-photon wave functions are shown to propagate equivalently. We give examples of beam-like states, which can be used as photon wave functions in PWM, or modes in QFT. We propose a practical mode converter based on spectral filtering to convert between wave packets and their corresponding biorthogonal dual wave packets.

  16. Physical measurements of breaking wave impact on a floating wave energy converter

    NASA Astrophysics Data System (ADS)

    Hann, Martyn R.; Greaves, Deborah M.; Raby, Alison

    2013-04-01

    Marine energy converter must both efficiently extract energy in small to moderate seas and also successfully survive storms and potential collisions. Extreme loads on devices are therefore an important consideration in their design process. X-MED is a SuperGen UKCMER project and is a collaboration between the Universities of Manchester, Edinburgh and Plymouth and the Scottish Association for Marine Sciences. Its objective is to extend the knowledge of extreme loads due to waves, currents, flotsam and mammal impacts. Plymouth Universities contribution to the X-MED project involves measuring the loading and response of a taut moored floating body due to steep and breaking wave impacts, in both long crested and directional sea states. These measurements are then to be reproduced in STAR-CCM+, a commercial volume of fluid CFD solver, so as to develop techniques to predict the wave loading on wave energy converters. The measurements presented here were conducted in Plymouth Universities newly opened COAST laboratories 35m long, 15.5m wide and 3m deep ocean basin. A 0.5m diameter taut moored hemispherical buoy was used to represent a floating wave energy device or support structure. The changes in the buoys 6 degree of freedom motion and mooring loads are presented due to focused breaking wave impacts, with the breaking point of the wave changed relative to the buoy.

  17. Wave parameters and functions in wavelet analysis with filtering

    Microsoft Academic Search

    M.-C. Huang

    2004-01-01

    This is a sequel to Huang’s paper entitled ‘Wave parameters and functions in wavelet analysis’ (Ocean Engineering, 2004, 31(1), 111–125) preliminary study of wave parameters and functions in wavelet analysis. Both discrete wavelet transform and median filtering techniques are applied to remove spiky noise from wind wave data obtained from a coastal observation tower. Fourier band-pass filters are also applied

  18. Gravity-related wave function collapse: Is superfluid He exceptional?

    E-print Network

    Lajos Diósi

    2013-02-21

    The gravity-related model of spontaneous wave function collapse, a longtime hypothesis, damps the massive Schr\\"odinger Cat states in quantum theory. We extend the hypothesis and assume that spontaneous wave function collapses are responsible for the emergence of Newton interaction. Superfluid helium would then show significant and testable gravitational anomalies.

  19. Measurement of Light-Cone Wave Functions by Diffractive Dissociation

    E-print Network

    Daniel Ashery

    2002-05-07

    Diffractive dissociation of particles can be used to study their light-cone wave functions. Results from Fermilab experiment E791 for diffractive dissociation of 500 GeV/c pi- mesons into di-jets show that the |q qbar> light-cone asymptotic wave function describes the data well for Q^2 ~ 10 (GeV/c)^2 or more.

  20. Plausible Suggestion for a Deterministic Wave Function

    E-print Network

    Petra Schulz

    2006-09-26

    A deterministic axial vector model for photons is presented which is suitable also for particles. During a rotation around an axis the deterministic wave function a has the following form a = ws r exp(+-i wb t). ws is either the axial or scalar spin rotation frequency (the latter is proportional to the mass), r radius of the orbit (also amplitude of a vibration arising later from the interaction by fusing of two oppositely circling photons), wb orbital angular frequency (proportional to the velocity) and t time. "+" before the imaginary i means a right-handed and "-" a left-handed rotation. An interaction happens if particles (including the photons) meet themselves through collision and melt together. ----- Es wird ein deterministisches Drehvektor-Modell fuer Photonen vorgestellt, das auch fuer Teilchen geeignet ist. Bei einer Kreisbewegung um eine Achse hat die deterministische Wellenfunktion a die folgende Form a = ws r exp(+-i wb t). Dabei bedeuten ws entweder die axiale oder die skalare Spin-Kreisfrequenz (letztere ist proportional der Masse), r Radius der Kreisbahn (auch Amplitude einer sich spaeter durch Wechselwirkung ergebenden Schwingung aus zwei entgegengesetzt kreisenden verschmolzenen Photonen), wb Kreisbahn-Frequenz (ein Mass fuer die Bahngeschwindigkeit) und t Zeit. Das "+" vor dem imaginaeren i bedeutet eine rechtshaendige und das "-" eine linkshaendige Rotation. Eine Wechselwirkung tritt ein, wenn sich Teilchen einschliesslich der Photonen durch Stossprozesse begegnen und dabei verschmelzen.

  1. Impact of Fog on Electromagnetic Wave Propagation

    NASA Astrophysics Data System (ADS)

    Morris, Jonathon; Fleisch, Daniel

    2002-04-01

    This experiment was designed to explore the impact of fog on electromagnetic radiation, in particular microwaves and infrared light. For years law enforcement agencies have used microwave radiation (radar guns) to measure the speed of vehicles, and the last ten years has seen increased use of LIDAR, which uses 905-nm infrared radiation rather than microwaves. To evaulate the effect of fog on the operation of these devices, we have constructed a fog chamber with microwave and optical portals to allow light from a HeNe laser and 10.6-GHz microwaves to propagate through various densities of fog. Data is acquired using Vernier Logger Pro and analyzed using MATLAB and Mathematica. Using the attenuation of the laser light to determine fog density, the impact of fog on the signal-to-noise ratio of both microwave and IR devices may be quantified, and the maximum useful range may be calculated.

  2. Violent breaking wave impacts. Part 1: Results from large-scale regular wave tests on vertical and sloping walls

    Microsoft Academic Search

    G. N. Bullock; C. Obhrai; D. H. Peregrine; H. Bredmose

    2007-01-01

    As part of an investigation into the detailed characteristics of wave impacts, experimental data are presented for the impact pressures and forces generated by waves up to 1.7 m high breaking onto a vertical wall and a wall inclined at 27° to the vertical. Particular attention is given to the influence of entrained and entrapped air and, by selecting regular wave

  3. Impact of rheumatoid arthritis on sexual function

    PubMed Central

    Tristano, Antonio G

    2014-01-01

    Sexuality is a complex aspect of the human being’s life and is more than just the sexual act. Normal sexual functioning consists of sexual activity with transition through the phases from arousal to relaxation with no problems, and with a feeling of pleasure, fulfillment and satisfaction. Rheumatic diseases may affect all aspects of life including sexual functioning. The reasons for disturbing sexual functioning are multifactorial and comprise disease-related factors as well as therapy. Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease characterized by progressive joint destruction resulting from chronic synovial inflammation. It leads to various degrees of disability, and ultimately has a profound impact on the social, economic, psychological, and sexual aspects of the patient’s life. This is a systemic review about the impact of RA on sexual functioning. PMID:24829873

  4. Symmetry-projected wave functions in quantum Monte Carlo calculations

    NASA Astrophysics Data System (ADS)

    Shi, Hao; Jiménez-Hoyos, Carlos A.; Rodríguez-Guzmán, R.; Scuseria, Gustavo E.; Zhang, Shiwei

    2014-03-01

    We consider symmetry-projected Hartree-Fock trial wave functions in constrained-path Monte Carlo (CPMC) calculations. Previous CPMC calculations have mostly employed Hartree-Fock (HF) trial wave functions, restricted or unrestricted. The symmetry-projected HF approach results in a hierarchy of wave functions with increasing quality: the more symmetries that are broken and restored in a self-consistent manner, the higher the quality of the trial wave function. This hierarchy is approximately maintained in CPMC calculations: the accuracy in the energy increases and the statistical variance decreases when further symmetries are broken and restored. Significant improvement is achieved in CPMC with the best symmetry-projected trial wave functions over those from simple HF. We analyze and quantify the behavior using the two-dimensional repulsive Hubbard model as an example. In the sign-problem-free region, where CPMC can be made exact but a constraint is deliberately imposed here, spin-projected wave functions remove the constraint bias. Away from half filling, spatial symmetry restoration in addition to that of the spin leads to highly accurate results from CPMC. Since the computational cost of symmetry-projected HF trial wave functions in CPMC can be made to scale algebraically with system size, this provides a potentially general approach for accurate calculations in many-fermion systems.

  5. Do Heat Waves have an Impact on Terrestrial Water Storage?

    NASA Astrophysics Data System (ADS)

    Brena-Naranjo, A.; Teuling, R.; Pedrozo-Acuña, A.

    2014-12-01

    Recent works have investigated the impact of heat waves on the surface energy and carbon balance. However, less attention has been given to the impacts on terrestrial hydrology. During the summer of 2010, the occurrence of an exceptional heat wave affected severely the Northern Hemisphere. The extension (more than 2 million km2) and severity of this extreme event caused substantial ecosystem damage (more than 1 million ha of forest fires), economic and human losses (~500 billion USD and more than 17 million of indirect deaths, respectively). This work investigates for the first time the impacts of the 2010 summer heat wave on terrestrial water storage. Our study area comprises three different regions where air temperature records were established or almost established during the summer: Western Russia, the Middle East and Eastern Sahel. Anomalies of terrestrial water storage derived from the Gravity Recovery and Climate Experiment (GRACE) were used to infer water storage deficits during the 2003-2013 period. Our analysis shows that Russia experienced the most severe water storage decline, followed by the Middle East, whereas Eastern Sahel was not significantly affected. The impact of the heat wave was spatially uniform in Russia but highly variable in the Middle East, with the Northern part substantially more affected than the Southern region. Lag times between maxima air temperatures and lower water storage deficits for Russia and the Middle East were approximately two and seven months, respectively. The results suggest that the response of terrestrial water storage to heat waves is stronger in energy-limited environments than in water-limited regions. Such differences in the magnitude and timing between meteorological and hydrological extremes can be explained by the propagation time between atmospheric water demand and natural or anthropogenic sources of water storage.

  6. Nonstandard jump functions for radically symmetric shock waves

    SciTech Connect

    Baty, Roy S [Los Alamos National Laboratory; Tucker, Don H [UNIV OF UTAH; Stanescu, Dan [UNIV OF WYOMING

    2008-01-01

    Nonstandard analysis is applied to derive generalized jump functions for radially symmetric, one-dimensional, magnetogasdynamic shock waves. It is assumed that the shock wave jumps occur on infinitesimal intervals and the jump functions for the physical parameters occur smoothly across these intervals. Locally integrable predistributions of the Heaviside function are used to model the flow variables across a shock wave. The equations of motion expressed in nonconservative form are then applied to derive unambiguous relationships between the jump functions for the physical parameters for two families of self-similar flows. It is shown that the microstructures for these families of radially symmetric, magnetogasdynamic shock waves coincide in a nonstandard sense for a specified density jump function.

  7. Boundary conditions on internal three-body wave functions

    SciTech Connect

    Mitchell, Kevin A.; Littlejohn, Robert G.

    1999-10-01

    For a three-body system, a quantum wave function {Psi}{sub m}{sup {ell}} with definite {ell} and m quantum numbers may be expressed in terms of an internal wave function {chi}{sub k}{sup {ell}} which is a function of three internal coordinates. This article provides necessary and sufficient constraints on {chi}{sub k}{sup {ell}} to ensure that the external wave function {Psi}{sub k}{sup {ell}} is analytic. These constraints effectively amount to boundary conditions on {chi}{sub k}{sup {ell}} and its derivatives at the boundary of the internal space. Such conditions find similarities in the (planar) two-body problem where the wave function (to lowest order) has the form r{sup |m|} at the origin. We expect the boundary conditions to prove useful for constructing singularity free three-body basis sets for the case of nonvanishing angular momentum.

  8. Nonstandard jump functions for radially symmetric shock waves

    SciTech Connect

    Baty, Roy S.; Tucker, Don H.; Stanescu, Dan

    2008-10-01

    Nonstandard analysis is applied to derive generalized jump functions for radially symmetric, one-dimensional, magnetogasdynamic shock waves. It is assumed that the shock wave jumps occur on infinitesimal intervals, and the jump functions for the physical parameters occur smoothly across these intervals. Locally integrable predistributions of the Heaviside function are used to model the flow variables across a shock wave. The equations of motion expressed in nonconservative form are then applied to derive unambiguous relationships between the jump functions for the physical parameters for two families of self-similar flows. It is shown that the microstructures for these families of radially symmetric, magnetogasdynamic shock waves coincide in a nonstandard sense for a specified density jump function

  9. Optimized Perturbation Theory for Wave Functions of Quantum Systems

    E-print Network

    T. Hatsuda; T. Kunihiro; T. Tanaka

    1996-12-10

    The notion of the optimized perturbation, which has been successfully applied to energy eigenvalues, is generalized to treat wave functions of quantum systems. The key ingredient is to construct an envelope of a set of perturbative wave functions. This leads to a condition similar to that obtained from the principle of minimal sensitivity. Applications of the method to quantum anharmonic oscillator and the double well potential show that uniformly valid wave functions with correct asymptotic behavior are obtained in the first-order optimized perturbation even for strong couplings.

  10. Optimized Perturbation Theory for Wave Functions of Quantum Systems

    E-print Network

    Hatsuda, T; Tanaka, T

    1997-01-01

    The notion of the optimized perturbation, which has been successfully applied to energy eigenvalues, is generalized to treat wave functions of quantum systems. The key ingredient is to construct an envelope of a set of perturbative wave functions. This leads to a condition similar to that obtained from the principle of minimal sensitivity. Applications of the method to quantum anharmonic oscillator and the double well potential show that uniformly valid wave functions with correct asymptotic behavior are obtained in the first-order optimized perturbation even for strong couplings.

  11. Measurement of Light-Cone Wave Functions by Diffractive Dissociation

    E-print Network

    Daniel Ashery

    2000-08-22

    Diffractive dissociation of particles can be used to study their light-cone wave function. Results from Fermilab experiment E791 for diffractive dissociation of 500 GeV/c $\\pi^-$ mesons into di-jets are presented. The results show that the $|q\\bar {q}>$ light-cone asymptotic wave function describes the data well for $Q^2 \\sim 10 ~{\\rm (GeV/c)^2}$ or more. Evidence for color transparency comes from a measurement of the $A$-dependence of the yield of the diffractive di-jets. It is proposed to carry out similar studies for the light-cone wave function of the photon.

  12. The response functions of electromagnetic wave logs and their applications

    Microsoft Academic Search

    Guanglong Xing; Shande Yang

    2006-01-01

    A fundamental feature of the electromagnetic wave logs is the logging response (phase difference and amplitude ratio) dependent on the both dielectric constant and conductivity in general. We derived the response functions (RF) of the electromagnetic wave logs and proposed their fast algorithm based on an integral equation of electromagnetic field and a weak scattering approximation. Using the fast algorithm

  13. Asymptotic scattering wave function for three charged particles and astrophysical capture processes 

    E-print Network

    Pirlepesov, Fakhriddin

    2006-08-16

    The asymptotic behavior of the wave functions of three charged particles has been investigated. There are two different types of three-body scattering wave functions. The first type of scattering wave function evolves from ...

  14. Impact of plunging breaking waves on a partially submerged cube

    NASA Astrophysics Data System (ADS)

    Wang, A.; Ikeda, C.; Duncan, J. H.

    2013-11-01

    The impact of a deep-water plunging breaking wave on a partially submerged cube is studied experimentally in a tank that is 14.8 m long and 1.2 m wide with a water depth of 0.91 m. The breakers are created from dispersively focused wave packets generated by a programmable wave maker. The water surface profile in the vertical center plane of the cube is measured using a cinematic laser-induced fluorescence technique with movie frame rates ranging from 300 to 4,500 Hz. The pressure distribution on the front face of the cube is measured with 24 fast-response sensors simultaneously with the wave profile measurements. The cube is positioned vertically at three heights relative to the mean water level and horizontally at a distance from the wave maker where a strong vertical water jet is formed. The portion of the water surface between the contact point on the front face of the cube and the wave crest is fitted with a circular arc and the radius and vertical position of the fitted circle is tracked during the impact. The vertical acceleration of the contact point reaches more than 50 times the acceleration of gravity and the pressure distribution just below the free surface shows a localized high-pressure region with a very high vertical pressure gradient. The impact of a deep-water plunging breaking wave on a partially submerged cube is studied experimentally in a tank that is 14.8 m long and 1.2 m wide with a water depth of 0.91 m. The breakers are created from dispersively focused wave packets generated by a programmable wave maker. The water surface profile in the vertical center plane of the cube is measured using a cinematic laser-induced fluorescence technique with movie frame rates ranging from 300 to 4,500 Hz. The pressure distribution on the front face of the cube is measured with 24 fast-response sensors simultaneously with the wave profile measurements. The cube is positioned vertically at three heights relative to the mean water level and horizontally at a distance from the wave maker where a strong vertical water jet is formed. The portion of the water surface between the contact point on the front face of the cube and the wave crest is fitted with a circular arc and the radius and vertical position of the fitted circle is tracked during the impact. The vertical acceleration of the contact point reaches more than 50 times the acceleration of gravity and the pressure distribution just below the free surface shows a localized high-pressure region with a very high vertical pressure gradient. This work is supported by the Office of Naval Research under grant N000141110095.

  15. Zeros of the Whittaker function associated to Coulomb waves

    NASA Astrophysics Data System (ADS)

    Esparza, J.; Lopez, J. L.; Sesma, J.

    1999-08-01

    The zeros in the complex z plane of the Whittaker function Wc/z,{micro}(z), closely related to spherical waves in the quantum-mechanical Coulomb problem, are investigated for varying real values of the parameters c and {micro}

  16. Multi-time wave functions for quantum field theory

    SciTech Connect

    Petrat, Sören, E-mail: petrat@math.lmu.de [Mathematisches Institut, Ludwig-Maximilians-Universität, Theresienstr. 39, 80333 München (Germany); Tumulka, Roderich, E-mail: tumulka@math.rutgers.edu [Department of Mathematics, Rutgers University, 110 Frelinghuysen Road, Piscataway, NJ 08854-8019 (United States)

    2014-06-15

    Multi-time wave functions such as ?(t{sub 1},x{sub 1},…,t{sub N},x{sub N}) have one time variable t{sub j} for each particle. This type of wave function arises as a relativistic generalization of the wave function ?(t,x{sub 1},…,x{sub N}) of non-relativistic quantum mechanics. We show here how a quantum field theory can be formulated in terms of multi-time wave functions. We mainly consider a particular quantum field theory that features particle creation and annihilation. Starting from the particle–position representation of state vectors in Fock space, we introduce multi-time wave functions with a variable number of time variables, set up multi-time evolution equations, and show that they are consistent. Moreover, we discuss the relation of the multi-time wave function to two other representations, the Tomonaga–Schwinger representation and the Heisenberg picture in terms of operator-valued fields on space–time. In a certain sense and under natural assumptions, we find that all three representations are equivalent; yet, we point out that the multi-time formulation has several technical and conceptual advantages. -- Highlights: •Multi-time wave functions are manifestly Lorentz-covariant objects. •We develop consistent multi-time equations with interaction for quantum field theory. •We discuss in detail a particular model with particle creation and annihilation. •We show how multi-time wave functions are related to the Tomonaga–Schwinger approach. •We show that they have a simple representation in terms of operator valued fields.

  17. The Maxwell wave function of the photon (Invited Paper)

    NASA Astrophysics Data System (ADS)

    Raymer, M. G.; Smith, Brian J.

    2005-08-01

    James Clerk Maxwell unknowingly discovered a correct relativistic, quantum theory for the light quantum, forty-three years before Einstein postulated the photon"s existence. In this theory, the usual Maxwell field is the quantum wave function for a single photon. When the non-operator Maxwell field of a single photon is second quantized, the standard Dirac theory of quantum optics is obtained. Recently, quantum-state tomography has been applied to experimentally determine photon wave functions.

  18. Nonorthogonal generalized Wannier function pseudopotential plane-wave method

    Microsoft Academic Search

    Chris-Kriton Skylaris; Arash A. Mostofi; Peter D. Haynes; Oswaldo Diéguez; Mike C. Payne

    2002-01-01

    We present a reformulation of the plane-wave pseudopotential method for insulators. This new approach allows us to perform density-functional calculations by solving directly for ``nonorthogonal generalized Wannier functions'' rather than extended Bloch states. We outline the theory on which our method is based and present test calculations on a variety of systems. Comparison of our results with a standard plane-wave

  19. Factorized molecular wave functions: Analysis of the nuclear factor.

    PubMed

    Lefebvre, R

    2015-06-01

    The exact factorization of molecular wave functions leads to nuclear factors which should be nodeless functions. We reconsider the case of vibrational perturbations in a diatomic species, a situation usually treated by combining Born-Oppenheimer products. It was shown [R. Lefebvre, J. Chem. Phys. 142, 074106 (2015)] that it is possible to derive, from the solutions of coupled equations, the form of the factorized function. By increasing artificially the interstate coupling in the usual approach, the adiabatic regime can be reached, whereby the wave function can be reduced to a single product. The nuclear factor of this product is determined by the lowest of the two potentials obtained by diagonalization of the potential matrix. By comparison with the nuclear wave function of the factorized scheme, it is shown that by a simple rectification, an agreement is obtained between the modified nodeless function and that of the adiabatic scheme. PMID:26049477

  20. NUMERICAL SIMULATION OF WAVE IMPACT ON A RIGID WALL USING A TWOPHASE COMPRESSIBLE SPH METHOD

    E-print Network

    Boyer, Edmond

    Results and Discussions 6 3.1 The Liquid Patch impact Test Case 7 3.2 Wave Impact on a Rigid Wall 8 4NUMERICAL SIMULATION OF WAVE IMPACT ON A RIGID WALL USING A TWO­PHASE COMPRESSIBLE SPH METHOD simulations. The two-phase SPH solver is then used to model a benchmark problem of liquid impact on a rigid

  1. Wave Function of a Photon and the Appropriate Lagrangian

    NASA Astrophysics Data System (ADS)

    Yamamoto, Takuo; Yamashita, Shinji; Yajima, Satoshi

    2012-02-01

    In electromagnetic theory, Maxwell's equations are usually regarded as classical ones, but they can be rewritten to have a form like the Dirac equation in relativistic quantum mechanics. We show that, if an electromagnetic wave is regarded as a many-particle system without the second quantization, these particles ``photons'' are massless and automatically have energy E=h?. The wave function ? of a photon satisfies the equations with the same form as the rewritten Maxwell's equations, but the Lagrangian and dynamical variables are different from the standard ones. To perform the second quantization, photons that satisfy the equations of wave functions with right- and left-handed helicities are treated together.

  2. Impact of internal waves on the coherent underwater acoustic communication

    NASA Astrophysics Data System (ADS)

    Wang, Jun; Yang, Xiaoxia; Wu, Lixin; Wang, Haibin; Lynch, James F.; Newhall, Arthur

    2012-11-01

    The 2001 Asian Sea International Experiment (ASIAEX2001) is a large-scale survey performed in the South China Sea. During May 2001 several minutes of M-sequence phase modulation signals were transmitted by a 400-Hz source repeatedly at intervals of half an hour, and received by an array 31 km away to conduct tomography of internal waves. The signal was treated as a binary-phase shift-keying (BPSK) communication signal with an information rate of 100 bps. The communication signals were demodulated by a decision-feedback equalizer. Since the intensity of the internal waves was not stable during the experiment period, data of two transmissions corresponding to a strong and a weak internal-wave activity were separately located and processed to investigate the impact of internal waves on the coherent underwater acoustic communication. The results show that internal waves cause a greatly fluctuating signal level and a rapidly varying multipath structure; consequently, these results show that the parameters of the equalizer need to be adjusted to mitigate the degradation of the communication performance.

  3. Does a measurement really collapse the wave function?

    E-print Network

    Sofia Wechsler

    2010-03-02

    A single-particle multi-branched wave-function is studied. Usual which-path tests show that if the detector placed on one branch clicks, the detectors on the other branches remain silent. By the collapse postulate, after this click, the state of the particle is reduced to a single branch, the branch on which the detector clicked. The present article challenges the collapse postulate, claiming that when one branch of the wave-function produces a click in a detector, the other branches don't disappear. They can't produce clicks in detectors, but they are still there. An experiment different from which-path test is proposed, which shows that detectors are responsible for strongly decohering the wave-function, but not for making parts of it disappear. Moreover, one of the branches supposed to disappear may produce an interference pattern with a wave-packet of another particle.

  4. Matter Density and Relativistic Models of Wave Function Collapse

    E-print Network

    Daniel Bedingham; Detlef Duerr; GianCarlo Ghirardi; Sheldon Goldstein; Roderich Tumulka; Nino Zanghi

    2013-07-12

    Mathematical models for the stochastic evolution of wave functions that combine the unitary evolution according to the Schroedinger equation and the collapse postulate of quantum theory are well understood for non-relativistic quantum mechanics. Recently, there has been progress in making these models relativistic. But even with a fully relativistic law for the wave function evolution, a problem with relativity remains: Different Lorentz frames may yield conflicting values for the matter density at a space-time point. We propose here a relativistic law for the matter density function. According to our proposal, the matter density function at a space-time point x is obtained from the wave function psi on the past light cone of x by setting the i-th particle position in |psi|^2 equal to x, integrating over the other particle positions, and averaging over i. We show that the predictions that follow from this proposal agree with all known experimental facts.

  5. Impact of sea-level rise and coral mortality on the wave dynamics and wave forces on barrier reefs.

    PubMed

    Baldock, T E; Golshani, A; Callaghan, D P; Saunders, M I; Mumby, P J

    2014-06-15

    A one-dimensional wave model was used to investigate the reef top wave dynamics across a large suite of idealized reef-lagoon profiles, representing barrier coral reef systems under different sea-level rise (SLR) scenarios. The modeling shows that the impacts of SLR vary spatially and are strongly influenced by the bathymetry of the reef and coral type. A complex response occurs for the wave orbital velocity and forces on corals, such that the changes in the wave dynamics vary reef by reef. Different wave loading regimes on massive and branching corals also leads to contrasting impacts from SLR. For many reef bathymetries, wave orbital velocities increase with SLR and cyclonic wave forces are reduced for certain coral species. These changes may be beneficial to coral health and colony resilience and imply that predicting SLR impacts on coral reefs requires careful consideration of the reef bathymetry and the mix of coral species. PMID:24768171

  6. Can the wave function in configuration space be replaced by single-particle wave functions in physical space?

    E-print Network

    Travis Norsen; Damiano Marian; Xavier Oriols

    2014-10-14

    The ontology of Bohmian mechanics includes both the universal wave function (living in 3N-dimensional configuration space) and particles (living in ordinary 3-dimensional physical space). Proposals for understanding the physical significance of the wave function in this theory have included the idea of regarding it as a physically-real field in its 3N-dimensional space, as well as the idea of regarding it as a law of nature. Here we introduce and explore a third possibility in which the configuration space wave function is simply eliminated -- replaced by a set of single-particle pilot-wave fields living in ordinary physical space. Such a re-formulation of the Bohmian pilot-wave theory can exactly reproduce the statistical predictions of ordinary quantum theory. But this comes at the rather high ontological price of introducing an infinite network of interacting potential fields (living in 3-dimensional space) which influence the particles' motion through the pilot-wave fields. We thus introduce an alternative approach which aims at achieving empirical adequacy (like that enjoyed by GRW type theories) with a more modest ontological complexity, and provide some preliminary evidence for optimism regarding the (once popular but prematurely-abandoned) program of trying to replace the (philosophically puzzling) configuration space wave function with a (totally unproblematic) set of fields in ordinary physical space.

  7. Solutions of the Maxwell equations and photon wave functions

    NASA Astrophysics Data System (ADS)

    Mohr, Peter J.

    2010-03-01

    Properties of six-component electromagnetic field solutions of a matrix form of the Maxwell equations, analogous to the four-component solutions of the Dirac equation, are described. It is shown that the six-component equation, including sources, is invariant under Lorentz transformations. Complete sets of eigenfunctions of the Hamiltonian for the electromagnetic fields, which may be interpreted as photon wave functions, are given both for plane waves and for angular-momentum eigenstates. Rotationally invariant projection operators are used to identify transverse or longitudinal electric and magnetic fields. For plane waves, the velocity transformed transverse wave functions are also transverse, and the velocity transformed longitudinal wave functions include both longitudinal and transverse components. A suitable sum over these eigenfunctions provides a Green function for the matrix Maxwell equation, which can be expressed in the same covariant form as the Green function for the Dirac equation. Radiation from a dipole source and from a Dirac atomic transition current are calculated to illustrate applications of the Maxwell Green function.

  8. Rapidity resummation for B-meson wave functions

    NASA Astrophysics Data System (ADS)

    Shen, Yue-Long; Wang, Yu-Ming

    2014-11-01

    Transverse-momentum dependent (TMD) hadronic wave functions develop light-cone divergences under QCD corrections, which are commonly regularized by the rapidity ? of gauge vector defining the non-light-like Wilson lines. The yielding rapidity logarithms from infrared enhancement need to be resummed for both hadronic wave functions and short-distance functions, to achieve scheme-independent calculations of physical quantities. We briefly review the recent progress on the rapidity resummation for B-meson wave functions which are the key ingredients of TMD factorization formulae for radiative-leptonic, semi-leptonic and non-leptonic B-meson decays. The crucial observation is that rapidity resummation induces a strong suppression of B-meson wave functions at small light-quark momentum, strengthening the applicability of TMD factorization in exclusive B-meson decays. The phenomenological consequence of rapidity-resummation improved B-meson wave functions is further discussed in the context of B ? ? transition form factors at large hadronic recoil.

  9. Theory and Computation of the Spheroidal Wave Functions

    E-print Network

    P. E. Falloon; P. C. Abbott; J. B. Wang

    2002-12-17

    In this paper we report on a package, written in the Mathematica computer algebra system, which has been developed to compute the spheroidal wave functions of Meixner [J. Meixner and R.W. Schaefke, Mathieusche Funktionen und Sphaeroidfunktionen, 1954] and is available online (www.physics.uwa.edu.au/~falloon/spheroidal/spheroidal.html). This package represents a substantial contribution to the existing software, since it computes the spheroidal wave functions to arbitrary precision for general complex parameters mu, nu, gamma and argument z; existing software can only handle integer mu, nu and does not give arbitrary precision. The package also incorporates various special cases and computes analytic power series and asymptotic expansions in the parameter gamma. The spheroidal wave functions of Flammer [C. Flammer, Spheroidal Wave Functions, 1957] are included as a special case of Meixner's more general functions. This paper presents a concise review of the general theory of spheroidal wave functions and a description of the formulas and algorithms used in their computation, and gives high-precision numerical examples.

  10. Impact of high-frequency nonlinear internal waves on plankton dynamics in Massachusetts Bay

    E-print Network

    Chen, Changsheng

    Impact of high-frequency nonlinear internal waves on plankton dynamics in Massachusetts Bay-Volume Coastal Ocean Model (FVCOM-NH) to study the impact of high- frequency nonlinear internal waves on plankton: (I) hydraulic jump; (II) strong internal wave-tidal current nonlinear interaction; and (III

  11. Characteristics of oceanic impact-induced large water waves---Re-evaluation of the tsunami hazard

    Microsoft Academic Search

    Kai Wünnemann; Robert Weiss; Kay Hofmann

    2007-01-01

    The potential hazard of a meteorite impact in the ocean is controversial with respect to the destructive power of generated large ocean waves (tsunamis). We used numerical modeling of hypervelocity impact to investigate the generation mechanism and the characteristics of the resulting waves up to a distance of 100-150 projectile radii. The wave signal is primarily controlled by the ratio

  12. Water waves of asteroid impact in the lakes

    NASA Astrophysics Data System (ADS)

    Antonov, Roman; Pelinovsky, Efim

    2014-05-01

    Meteorite fall occurred in Chelyabinsk (Russia) on February 15, 2013 results a damage in Chelyabink and nearest villages, 1613 injured. The eruption energy is estimated in 600 kilotons of TNT. One of the big fragments up to 650 kg falls in the Chebarkul Lake covered by ice with thickness of 70 cm. The diameter of the hole in ice is 7-8 m. Maximal depth of the lake is 13.5 m and its square is 19.8 km^2. This event pays attention to the possible waves of the asteroid origin in water basins. Known theories of generation of water waves are applied to estimate the hazardous parameters of the meteorite impact in the lakes.

  13. Functional measures of stream impact assessment

    SciTech Connect

    Hill, B.H. [Environmental Protection Agency, Cincinnati, OH (United States)

    1994-12-31

    The effects of elevated metals (primarily Zn) in a Rocky Mountain stream were assessed using measures of primary productivity, community respiration, and phosphatase activity. Primary productivity was measured as rates of mass and chlorophyll a accumulation on ceramic tiles, and as O{sub 2}, evolution from natural substrates incubated in situ in closed chambers. Community respiration was measured in situ by incubating fine-grained sediments, collected and composited along each stream study reach, in closed chambers and measuring O{sub 2} depletion. Alkaline and acid phosphatase activity were measured for periphyton scraped from ceramic tiles and natural substrates. Primary productivity, measured as chlorophyll accretion rates and O{sup 2} evolution, were depressed by increasing Zn concentrations. Productivity measured as mass accretion rates did not show significant Zn effects. Community respiration was depressed by increasing Zn concentrations, as was alkaline phosphatase activity. Acid phosphatase activity was higher at the more impacted sites. Overall, functional measures were able to discern those sites receiving greater metal impacts from less impacted sites.

  14. General trial wave functions for a three body interaction

    NASA Astrophysics Data System (ADS)

    Ganesh Jaya, Sreejith; Toke, Csaba; Jain, Jainendra

    2010-03-01

    The Pfaffian wave function, which is a candidate for the 5/2 FQHE state, is the exact ground state of a short range three body model interaction, but little is known about the solutions of this model at other filling factors. Our starting point is the observation that the Pfaffian can be obtained by fully anti-symmetrizing a bilayer wave function of Halperin. A more general class of composite fermion wave functions for bilayer systems was constructed by Scarola and Jain. We find that, upon full antisymmetrization, these wave function provide a decent approximation to the low energy solutions of the three body model interaction at filling factors other than 1/2. The charged and neutral excitations of the full state are naturally constructed by creating excitations in one or both ``layers.'' We also investigate how well the ground and excited state wave functions work for the Coulomb interaction, both in the lowest and the second Landau levels. Systems with up to 18 particles are studied by a combination of exact diagonalization and Monte Carlo method.

  15. Wave-function equations for photons and electrons

    NASA Astrophysics Data System (ADS)

    Broyles, A. A.

    1982-09-01

    The wave equations for photons and electrons are presented. The wave functions must include positrons as particles as well as electrons and photons. These differential equations are shown to be equivalent to the unrenormalized perturbation series generated by Feynman rules. The procedure for replacing the bare mass and charge by the experimental values (renormalization) is illustrated for the case of the dressed electron. The introduction of atomic nuclei is discussed.

  16. POINTWISE GREEN FUNCTION BOUNDS AND STABILITY OF COMBUSTION WAVES

    Microsoft Academic Search

    GREGORY LYNG; MOHAMMADREZA ROOFI; BENJAMIN TEXIER; KEVIN ZUMBRUN

    2008-01-01

    Generalizing similar results for viscous shock and relaxation waves, we establish sharp pointwise Green function bounds and linearized and nonlinear stability for traveling wave solutions of an abstract viscous combustion model including both Majda's model and the full reacting compressible Navier-Stokes equations with artificial viscosity with general multi-species reaction and reaction-dependent equation of state, under the necessary condi- tions of

  17. Has the impact of heat waves on mortality changed in France since the European heat wave of summer 2003? A study of the 2006 heat wave

    E-print Network

    Boyer, Edmond

    Has the impact of heat waves on mortality changed in France since the European heat wave of summer mortality during the 2006 heat wave was compared to the expected excess mortality. Methods A Poisson regression model relating the daily fluctuations in summer temperature and mortality in France from 1975

  18. Charmed quark component of the photon wave function

    NASA Astrophysics Data System (ADS)

    Anisovich, V. V.; Dakhno, L. G.; Markov, V. N.; Nikonov, V. A.; Sarantsev, A. V.

    2005-12-01

    We determine the c-anti-c component of the photon wave function on the basis of (i) the data on the transitions e+ e- -> J/psi(3096), psi(3686), psi(4040), psi(4415), (ii) partial widths of the two-photon decays eta_{c0}(2979), chi_{c0}(3415), chi_{c2}(3556) -> gamma-gamma, and (iii) wave functions of the charmonium states obtained by solving the Bethe-Salpeter equation for the c-anti-c system. Using the obtained c-anti-c component of the photon wave function we calculate the gamma-gamma decay partial widths for radial excitation 2S state, eta_{c0}(3594) -> gamma-gamma, and 2P states chi_{c0}(3849), chi_{c2}(3950) -> gamma-gamma.

  19. Monitoring the wave function by time continuous position measurement

    E-print Network

    Thomas Konrad; Andreas Rothe; Francesco Petruccione; Lajos Diósi

    2009-02-13

    We consider a single copy of a quantum particle moving in a potential and show that it is possible to monitor its complete wave function by only continuously measuring its position. While we assume that the potential is known, no information is available about its state initially. In order to monitor the wave function, an estimate of the wave function is propagated due to the influence of the potential and continuously updated according to the results of the position measurement. We demonstrate by numerical simulations that the estimation reaches arbitrary values of accuracy below 100 percent within a finite time period for the potentials we study. In this way our method grants, a certain time after the beginning of the measurement, an accurate real-time record of the state evolution including the influence of the continuous measurement. Moreover, it is robust against sudden perturbations of the system as for example random momentum kicks from environmental particles, provided they occur not too frequently.

  20. Correlated continuum wave functions for three particles with Coulomb interactions

    SciTech Connect

    Gasaneo, G.; Colavecchia, F.D.; Garibotti, C.R. [Centro Atomico Bariloche and Consejo Nacional de Investigaciones Cientificas y Tecnicas, 8400 San Carlos de Bariloche, Rio Negro (Argentina)] [Centro Atomico Bariloche and Consejo Nacional de Investigaciones Cientificas y Tecnicas, 8400 San Carlos de Bariloche, Rio Negro (Argentina); Miraglia, J.E.; Macri, P. [Instituto de Astronomia y Fisica del Espacio, Consejo Nacional de Investigaciones Cientificas y Tecnicas, Casilla de Correo 67, Sucursal 28, 1428 Buenos Aires (Argentina)] [Instituto de Astronomia y Fisica del Espacio, Consejo Nacional de Investigaciones Cientificas y Tecnicas, Casilla de Correo 67, Sucursal 28, 1428 Buenos Aires (Argentina)

    1997-04-01

    We present an approximate solution of the Schr{umlt o}dinger equation for the three-body Coulomb problem. We write the Hamiltonian in parabolic curvilinear coordinates and study the possible separation of the wave equation as a system of coupled partial differential equations. When two of the particles are heavier than the others, we write an approximate wave equation that incorporates some terms of the Hamiltonian that before had been considered as a perturbation. Its solution can be expressed in terms of a confluent hypergeometric function of two variables. We show that the proposed wave function includes a correlation between the motion of the light particle relative to the heavy particles and verifies the correct asymptotic behavior when all particles are far from each other. Finally, we discuss the possible uses of this function in the calculation of transition matrices and differential cross sections in ionizing collisions. {copyright} {ital 1997} {ital The American Physical Society}

  1. Transverse instability of a plane front of fast impact ionization waves

    SciTech Connect

    Kyuregyan, A. S., E-mail: ask@vei.ru [All-Russia Institute of Electrical Engineering (Russian Federation)

    2012-05-15

    The transverse instability of a plane front of fast impact ionization waves in p{sup +}-n-n{sup +} semiconductor structures with a finite concentration of donors N in the n layer has been theoretically analyzed. It is assumed that the high velocity u of impact ionization waves is ensured owing to the avalanche multiplication of the uniform background of electrons and holes whose concentration {sigma}{sub b} ahead of the front is high enough for the continuum approximation to be applicable. The problem of the calculation of the growth rate s of a small harmonic perturbation with wavenumber k is reduced to the eigenvalue problem for a specific homogeneous Volterra equation of the second kind containing the sum of double and triple integrals of an unknown eigenfunction. This problem has been solved by the method of successive approximations. It has been shown that the function s(k) for small k values increases monotonically in agreement with the analytical theory reported in Thermal Engineering 58 (13), 1119 (2011), reaches a maximum s{sub M} at k = k{sub M}, then decreases, and becomes negative at k > k{sub 01}. This behavior of the function s(k) for short-wavelength perturbations is due to a decrease in the distortion of the field owing to a finite thickness of the space charge region of the front and 'smearing' of perturbation of concentrations owing to the transverse transport of charge carriers. The similarity laws for perturbations with k Greater-Than-Or-Equivalent-To k{sub M} have been established: at fixed {sigma}{sub b} values and the maximum field strength on the front E{sub 0M}, the growth rate s depends only on the ratio k/N and the boundary wavenumber k{sub 01} {proportional_to} N. The parameters s{sub M}, k{sub M}, and k{sub 01}, which determine the perturbation growth dynamics and the upper boundary of the instability region for impact ionization waves, have been presented as functions of E{sub 0M}. These dependences indicate that the model of a plane impact ionization wave is insufficient for describing the operation of avalanche voltage sharpers and that fronts of fast streamers in the continuum approximation should be stable with respect to transverse perturbations in agreement with the previously reported numerical simulation results. The results have been confirmed by the numerical simulation of the evolution of small harmonic perturbations of the steady-state plane impact ionization wave.

  2. Quantum Corral Wave-function Engineering

    NASA Astrophysics Data System (ADS)

    Correa, Alfredo; Reboredo, Fernando; Balseiro, Carlos

    2005-03-01

    We present a theoretical method for the design and optimization of quantum corrals[1] with specific electronic properties. Taking advantage that spins are subject to a RKKY interaction that is directly controlled by the scattering of the quantum corral, we design corral structures that reproduce spin Hamiltonians with coupling constants determined a priori[2]. We solve exactly the bi-dimensional scattering problem for each corral configuration within the s-wave approximation[3] and subsequently the geometry of the quantum corral is optimized by means of simulated annealing[4] and genetic algorithms[5]. We demonstrate the possibility of automatic design of structures with complicated target electronic properties[6]. This work was performed under the auspices of the US Department of Energy by the University of California at the LLNL under contract no W-7405-Eng-48. [1] M. F. Crommie, C. P. Lutz and D. M. Eigler, Nature 403, 512 (2000) [2] D. P. DiVincenzo et al., Nature 408, 339 (2000) [3] G. A. Fiete and E. J. Heller, Rev. Mod. Phys. 75, 933 (2003) [4] M. R. A. T. N. Metropolis et al., J. Chem. Phys. 1087 (1953) [5] E. Aarts and J. K. Lenstra, eds. Local search in combinatorial problems (Princeton University Press, 1997) [6] A. A. Correa, F. Reboredo and C. Balseiro, Phys. Rev. B (in press).

  3. Impact of autocorrelation on functional connectivity.

    PubMed

    Arbabshirani, Mohammad R; Damaraju, Eswar; Phlypo, Ronald; Plis, Sergey; Allen, Elena; Ma, Sai; Mathalon, Daniel; Preda, Adrian; Vaidya, Jatin G; Adali, Tülay; Calhoun, Vince D

    2014-11-15

    Although the impact of serial correlation (autocorrelation) in residuals of general linear models for fMRI time-series has been studied extensively, the effect of autocorrelation on functional connectivity studies has been largely neglected until recently. Some recent studies based on results from economics have questioned the conventional estimation of functional connectivity and argue that not correcting for autocorrelation in fMRI time-series results in "spurious" correlation coefficients. In this paper, first we assess the effect of autocorrelation on Pearson correlation coefficient through theoretical approximation and simulation. Then we present this effect on real fMRI data. To our knowledge this is the first work comprehensively investigating the effect of autocorrelation on functional connectivity estimates. Our results show that although FC values are altered, even following correction for autocorrelation, results of hypothesis testing on FC values remain very similar to those before correction. In real data we show this is true for main effects and also for group difference testing between healthy controls and schizophrenia patients. We further discuss model order selection in the context of autoregressive processes, effects of frequency filtering and propose a preprocessing pipeline for connectivity studies. PMID:25072392

  4. SLE description of the nodal lines of random wave functions

    E-print Network

    E. Bogomolny; R. Dubertrand; C. Schmit

    2006-09-07

    The nodal lines of random wave functions are investigated. We demonstrate numerically that they are well approximated by the so-called SLE_6 curves which describe the continuum limit of the percolation cluster boundaries. This result gives an additional support to the recent conjecture that the nodal domains of random (and chaotic) wave functions in the semi classical limit are adequately described by the critical percolation theory. It is also shown that using the dipolar variant of SLE reduces significantly finite size effects.

  5. Measuring Chirally Odd Wave Functions with Helicity Flip Form Factors

    E-print Network

    Pankaj Jain; John P. Ralston

    1993-05-12

    We consider the role of chirally odd wave functions in hard exclusive reactions. Such wave functions have the quarks oriented in the opposite helicity configuration from those assumed in the short-distance limit and are generally associated with non-zero orbital angular momentum. Calculations in the impulse approximation allow for non-zero helicity flip amplitudes while the conventional factorization prescription for exclusive processes does not. By introducing a new approach, we show how helicity flip form factors are nevertheless calculable in QCD.

  6. Many-body wave function in a dipole blockade configuration

    SciTech Connect

    Robicheaux, F.; Hernandez, J. V. [Department of Physics, Auburn University, Alabama 36849-5311 (United States)

    2005-12-15

    We report the results of simulations of the many atom wave function when a cold gas is excited to highly excited states. We simulated the many body wave function by direct numerical solution of Schroedinger's equation. We investigated the fraction of atoms excited and the correlation of excited atoms in the gas for different types of excitation when the blockade region was small compared to the sample size. We also investigated the blockade effect when the blockade region is comparable to the sample size to determine the sensitivity of this system and constraints for quantum information.

  7. Concerning Infeasibility of the Wave Functions of the Universe

    E-print Network

    Arkady Bolotin

    2015-02-04

    Difficulties with finding the general exact solutions to the Wheeler-DeWitt equation, i.e. the wave functions of the Universe, are known and well documented. However, the present paper draws attention to a completely different matter, which is rarely if ever discussed in relation to this equation, namely, the time complexity of the Wheeler-DeWitt equation, that is, the time required to exactly solve the equation for a given universe. As it is shown in the paper, whatever generic exact algorithm is used to solve the equation, most likely such an algorithm cannot be faster than brute force, which makes the wave functions of the Universe infeasible.

  8. Simulation of wave-function microscopy images of Stark resonances

    NASA Astrophysics Data System (ADS)

    Zhao, L. B.; Xiao, D. H.; Fabrikant, I. I.

    2015-04-01

    Wave-function microscopy images for Stark resonance states of H atoms are simulated using the quantum-mechanical formalism developed previously. Spatial distributions of ejected electron current densities are compared with experiment, and a good agreement is shown. The nonzero values of minima in the experimentally observed electron current distributions are reproduced by convoluting the theoretical current distribution with an instrumental function representing uncertainties in the position. Our relative strengths of the ejected electron current densities differ from those calculated with the wave packet propagation technique. We show that for the full convergence of the calculation, the distance between the ionized atom and the detector should exceed 10 ? m .

  9. On Spontaneous Wave Function Collapse and Quantum Field Theory

    E-print Network

    Roderich Tumulka

    2005-12-15

    One way of obtaining a version of quantum mechanics without observers, and thus of solving the paradoxes of quantum mechanics, is to modify the Schroedinger evolution by implementing spontaneous collapses of the wave function. An explicit model of this kind was proposed in 1986 by Ghirardi, Rimini, and Weber (GRW), involving a nonlinear, stochastic evolution of the wave function. We point out how, by focussing on the essential mathematical structure of the GRW model and a clear ontology, it can be generalized to (regularized) quantum field theories in a simple and natural way.

  10. Calculation of the nucleon structure function from the nucleon wave function

    NASA Technical Reports Server (NTRS)

    Hussar, Paul E.

    1993-01-01

    Harmonic oscillator wave functions have played an historically important role in our understanding of the structure of the nucleon, most notably by providing insight into the mass spectra of the low-lying states. High energy scattering experiments are known to give us a picture of the nucleon wave function at high-momentum transfer and in a frame in which the nucleon is traveling fast. A simple model that crosses the twin bridges of momentum scale and Lorentz frame that separate the pictures of the nucleon wave function provided by the deep inelastic scattering data and by the oscillator model is presented.

  11. A new probability distribution function of wave steepness

    NASA Astrophysics Data System (ADS)

    Jiang, Xiulan; Zheng, Guizhen; Pei, Yuhua

    2008-08-01

    Wave steepness is an important characteristic describing the severity of sea state in ocean engineering. In the existing theoretical and experimental studies, wave steepness is often substituted by some related quantities. In this paper, a new probability density function (pdf) of steepness, which is a pdf of the steepness in its original definition, is obtained for narrowband Gaussian processes. The drawback inherent in the previous theoretical pdfs of steepness, that is, the probability density at zero steepness is nonzero, has been eliminated. Laboratory experiments were conducted in a wind-wave flume to measure the wave steepness distribution. Comparisons among laboratory measurements and some theoretical pdfs of steepness show that the new pdf generally fits the data better than the one proposed by Zheng et al. (1999).

  12. Hydrodynamic waves and correlation functions in dusty plasmas

    SciTech Connect

    Wang, X.; Bhattacharjee, A. [Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242 (United States)] [Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242 (United States)

    1997-11-01

    A hydrodynamic description of strongly coupled dusty plasmas is given when physical quantities vary slowly in space and time and the system can be assumed to be in local thermodynamic equilibrium. The linear waves in such a system are analyzed. In particular, a dispersion equation is derived for low-frequency dust acoustic waves, including collisional damping effects, and compared with experimental results. The linear response of the system is calculated from the fluctuation-dissipation theorem and the hydrodynamic equations. The requirement that these two calculations coincide constrains the particle correlation function for slowly varying perturbations. It is shown that in the presence of weakly damped, long-wavelength dust-acoustic waves, the dust autocorrelation function is of the Debye{endash}H{umlt u}ckel form and the characteristic shielding distance is the dust Debye length. {copyright} {ital 1997 American Institute of Physics.}

  13. Hydrodynamic waves and correlation functions in dusty plasmas

    NASA Astrophysics Data System (ADS)

    Wang, Xiaogang; Bhattacharjee, A.

    1997-11-01

    A hydrodynamic description of strongly coupled dusty plasmas is given when physical quantities vary slowly in space and time and the system can be assumed to be in local thermodynamic equilibrium. The linear waves in such a system are analyzed. In particular, a dispersion equation is derived for low-frequency dust acoustic waves, including collisional damping effects, and compared with experimental results. The linear response of the system is calculated from the fluctuation-dissipation theorem and the hydrodynamic equations. The requirement that these two calculations coincide constrains the particle correlation function for slowly varying perturbations. It is shown that in the presence of weakly damped, long-wavelength dust-acoustic waves, the dust autocorrelation function is of the Debye-Hückel form and the characteristic shielding distance is the dust Debye length.

  14. Precanonical Quantization and the Schrödinger Wave Functional Revisited

    E-print Network

    I. V. Kanatchikov

    2013-04-04

    We address the long-standing issue of the relation between the Schr\\"odinger functional representation in quantum field theory and the approach of precanonical field quantization which requires neither a distinguished time variable nor infinite-dimensional spaces of field configurations. The functional Schr\\"odinger equation is derived in the limiting case \\varkappa \\rightarrow \\delta(0) from the Dirac-like covariant generalization of the Schr\\"odinger equation within the precanonical quantization approach, where the constant \\varkappa of the dimension of the inverse spatial volume naturally appears on dimensional grounds. An explicit expression of the Schr\\"odinger wave functional as a continuous product of precanonical wave functions on the finite-dimensional covariant configuration space of the field and space-time variables is obtained.

  15. Study of Kinematics of Extreme Waves Impacting Offshore and Coastal Structures by Non Intrusive Measurement Techniques 

    E-print Network

    Song, Youn Kyung

    2013-11-07

    ...................... 64 III.1.3 Breaking wave mechanics and air entrapment effects ............................ 65 III.1.4 Influences of air entrapments on laboratory scale wave dynamics .......... 67 III.1.5 Objectives and outlines of this chapter.... Furthermore, the breaking wave entraps air bubbles of various sizes beneath the free surface and form a water-air mixed flow. The flow aeration during the wave breaking process affect various dynamic properties of wave flows, such as impact pressure...

  16. Percolation model for nodal domains of chaotic wave functions

    E-print Network

    E. Bogomolny; C. Schmit

    2001-10-09

    Nodal domains are regions where a function has definite sign. In recent paper [nlin.CD/0109029] it is conjectured that the distribution of nodal domains for quantum eigenfunctions of chaotic systems is universal. We propose a percolation-like model for description of these nodal domains which permits to calculate all interesting quantities analytically, agrees well with numerical simulations, and due to the relation to percolation theory opens the way of deeper understanding of the structure of chaotic wave functions.

  17. Analytic Properties of Bloch Waves and Wannier Functions

    Microsoft Academic Search

    W. Kohn

    1959-01-01

    The one-dimensional Schrödinger equation with a periodic and symmetric potential is considered, under the assumption that the energy bands do not intersect. The Bloch waves, varphin,k, and energy bands, En,k, are studied as functions of the complex variable, k. In the complex plane, they are branches of multivalued analytic and periodic functions, varphik, and Ek, with branch points, k', off

  18. Vector Meson Form Factors and Wave Functions from Holographic QCD

    Microsoft Academic Search

    Hovhannes Grigoryan; Anatoly Radyushkin

    2007-01-01

    Based on the holographic dual model of QCD, we study 2- and 3-point functions of vector currents and derive form factors as well as wave functions for the vector mesons. As a result, generalized vector-meson dominance representation for form factors is obtained with a very specific VMD pattern. The calculated electric radius of the rho-meson is shown to be in

  19. Vector Meson Form Factors and Wave Functions from Holographic QCD

    SciTech Connect

    Hovhannes Grigoryan; Anatoly Radyushkin

    2007-10-10

    Based on the holographic dual model of QCD, we study 2- and 3-point functions of vector currents and derive form factors as well as wave functions for the vector mesons. As a result, generalized vector-meson dominance representation for form factors is obtained with a very specific VMD pattern. The calculated electric radius of the rho-meson is shown to be in a good agreement with predictions from lattice QCD.

  20. Antisymmetric wave functions for mixed fermion states and energy convexity

    Microsoft Academic Search

    Antonios Gonis; Xiaoguang Zhang; Don M Nicholson; George Malcolm Stocks

    2011-01-01

    We show how ensembles or mixed states can be described in terms of pure states that for Fermions lead to wave functions that are antisymmetric with respect to interchange of particle coordinates (and spin). The pure states are constructed in an augmented Hilbert space spanned by products of ensemble states projected onto mutually nonoverlapping coordinates that prevents the appearance of

  1. Bohmian Mechanics and the Meaning of the Wave Function

    E-print Network

    Goldstein, Sheldon

    Bohmian Mechanics and the Meaning of the Wave Function D. Durr Mathematisches Institut der successes, quantum mechanics has, since its inception some seventy years ago, been plagued by conceptual di is not merely one of the conceptual di culties of quantum mechanics; it is the conceptual di culty. While we

  2. Bohmian Mechanics and the Meaning of the Wave Function

    E-print Network

    Goldstein, Sheldon

    Bohmian Mechanics and the Meaning of the Wave Function D. D¨urr Mathematisches Institut der predictive successes, quantum mechanics has, since its inception some seventy years ago, been plagued the measurement problem is not merely one of the conceptual difficulties of quantum mechanics

  3. Wave function statistics and multifractality in disordered systems

    E-print Network

    Fominov, Yakov

    Wave function statistics and multifractality in disordered systems Alexander D. Mirlin-localization correction to resistivity G | i Ai|2 = |Ai|2 + i=j A i Aj generically A i Aj 0 but: time-reversed paths: Ai = Ai · mesoscopic conductance fluctuations (G)2 ( i=j A i Aj)2 i=j |Ai|2 |Aj|2 Calculus: Green

  4. Wave function renormalization in heavy baryon chiral perturbation theory

    E-print Network

    G. Ecker; M. Mojzis

    1997-08-05

    We establish exact relations between relativistic form factors and amplitudes for single-baryon processes and the corresponding quantities calculated in the framework of heavy baryon chiral perturbation theory. A crucial ingredient for the proper matching is the first complete treatment of baryon wave function renormalization in heavy baryon chiral perturbation theory.

  5. Topological wave functions and heat equations

    E-print Network

    Murat Gunaydin; Andrew Neitzke; Boris Pioline

    2008-01-10

    It is generally known that the holomorphic anomaly equations in topological string theory reflect the quantum mechanical nature of the topological string partition function. We present two new results which make this assertion more precise: (i) we give a new, purely holomorphic version of the holomorphic anomaly equations, clarifying their relation to the heat equation satisfied by the Jacobi theta series; (ii) in cases where the moduli space is a Hermitian symmetric tube domain $G/K$, we show that the general solution of the anomaly equations is a matrix element $\\IP{\\Psi | g | \\Omega}$ of the Schr\\"odinger-Weil representation of a Heisenberg extension of $G$, between an arbitrary state $\\bra{\\Psi}$ and a particular vacuum state $\\ket{\\Omega}$. Based on these results, we speculate on the existence of a one-parameter generalization of the usual topological amplitude, which in symmetric cases transforms in the smallest unitary representation of the duality group $G'$ in three dimensions, and on its relations to hypermultiplet couplings, nonabelian Donaldson-Thomas theory and black hole degeneracies.

  6. Classical representation of wave functions for integrable systems

    SciTech Connect

    Kay, Kenneth G. [Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900 (Israel)

    2004-06-01

    Classical exact (CE) wave functions are certain integral representations of energy eigenfunctions that are parameterized in terms of the motion of the corresponding classical system in a semiclassically relevant way. When applied to systems for which they are not exact, such expressions serve as semiclassical approximations. Previous work identified CE wave functions for a number of specific systems and established their semiclassical usefulness. This paper explores the degree to which such representations can be found for more general systems. It is shown that CE wave functions exist, in principle, for bound states of an arbitrary integrable system that are confined to a single classically allowed region. Evidence is presented that CE representations also exist for more general states of such a system that are unbound, or that extend over more than one allowed region. The CE expressions are not unique: an innumerable variety exists for each such system. The existence proof provides a formal method for constructing CE expressions by Fourier transforming certain superpositions of energy eigenstates. The parameterization in terms of the classical motion is achieved by identifying certain quantities in these superpositions as classical action and angle variables. The semiclassical relevance of this identification is ensured by imposing some mild conditions on the coefficients in the superposition. This procedure for parameterizing exact wave functions in terms of classical variables indicates a basic relationship between the quantum and classical descriptions of states. The method of constructing CE wave functions introduced in the proof is shown to be consistent with a number of previously obtained CE formulas and is used to derive two new, closed-form, CE expressions. A simple numerical example is presented to illustrate the semiclassical application of one of these expressions and to further verify the physical significance of the classical parameterization.

  7. Refined applications of the collapse of the wave function

    NASA Astrophysics Data System (ADS)

    Stodolsky, L.

    2015-05-01

    In a two-part system, the collapse of the wave function of one part can put the other part in a state which would be difficult or impossible to achieve otherwise, in particular, one sensitive to small effects in the "collapse" interaction. We present some applications to the very symmetric and experimentally accessible situations of the decays ? (1020 )?KoKo , ? (3770 )?DoDo, or ? (4 s )?BoBo , involving the internal state of the two-state Ko, Do, or Bo mesons. The collapse of the wave function occasioned by a decay of one member of the pair (away side) fixes the state vector of that side's two-state system. Bose-Einstein statistics then determines the state of the recoiling meson (near side), whose evolution can then be followed further. In particular, the statistics requirement dictates that the "away side" and "near side" internal wave functions must be orthogonal at the time of the collapse. Thus a C P violation in the away side decay implies a complementary C P impurity on the near side, which can be detected in the further evolution. The C P violation so manifested is necessarily direct C P violation, since neither the mass matrix nor time evolution was involved in the collapse. A parametrization of the direct C P violation is given, and various manifestations are presented. Certain rates or combination of rates are identified which are nonzero only if there is direct C P violation. The very explicit and detailed use made of the collapse of the wave function makes the procedure interesting with respect to the fundamentals of quantum mechanics. We note an experimental consistency test for our treatment of the collapse of the wave function, which can be carried out by a certain measurement of partial decay rates.

  8. Simulation of wind wave growth with reference source functions

    NASA Astrophysics Data System (ADS)

    Badulin, Sergei I.; Zakharov, Vladimir E.; Pushkarev, Andrei N.

    2013-04-01

    We present results of extensive simulations of wind wave growth with the so-called reference source function in the right-hand side of the Hasselmann equation written as follows First, we use Webb's algorithm [8] for calculating the exact nonlinear transfer function Snl. Second, we consider a family of wind input functions in accordance with recent consideration [9] ( )s S = ?(k)N , ?(k) = ? ? ?- f (?). in k 0 ?0 in (2) Function fin(?) describes dependence on angle ?. Parameters in (2) are tunable and determine magnitude (parameters ?0, ?0) and wave growth rate s [9]. Exponent s plays a key role in this study being responsible for reference scenarios of wave growth: s = 4-3 gives linear growth of wave momentum, s = 2 - linear growth of wave energy and s = 8-3 - constant rate of wave action growth. Note, the values are close to ones of conventional parameterizations of wave growth rates (e.g. s = 1 for [7] and s = 2 for [5]). Dissipation function Sdiss is chosen as one providing the Phillips spectrum E(?) ~ ?5 at high frequency range [3] (parameter ?diss fixes a dissipation scale of wind waves) Sdiss = Cdiss?4w?N (k)?(? - ?diss) (3) Here frequency-dependent wave steepness ?2w = E(?,?)?5-g2 makes this function to be heavily nonlinear and provides a remarkable property of stationary solutions at high frequencies: the dissipation coefficient Cdiss should keep certain value to provide the observed power-law tails close to the Phillips spectrum E(?) ~ ?-5. Our recent estimates [3] give Cdiss ? 2.0. The Hasselmann equation (1) with the new functions Sin, Sdiss (2,3) has a family of self-similar solutions of the same form as previously studied models [1,3,9] and proposes a solid basis for further theoretical and numerical study of wave evolution under action of all the physical mechanisms: wind input, wave dissipation and nonlinear transfer. Simulations of duration- and fetch-limited wind wave growth have been carried out within the above model setup to check its conformity with theoretical predictions, previous simulations [2,6,9], experimental parameterizations of wave spectra [1,4] and to specify tunable parameters of terms (2,3). These simulations showed realistic spatio-temporal scales of wave evolution and spectral shaping close to conventional parameterizations [e.g. 4]. An additional important feature of the numerical solutions is a saturation of frequency-dependent wave steepness ?w in short-frequency range. The work was supported by the Russian government contract No.11.934.31.0035, Russian Foundation for Basic Research grant 11-05-01114-a and ONR grant N00014-10-1-0991. References [1] S. I. Badulin, A. V. Babanin, D. Resio, and V. Zakharov. Weakly turbulent laws of wind-wave growth. J. Fluid Mech., 591:339-378, 2007. [2] S. I. Badulin, A. N. Pushkarev, D. Resio, and V. E. Zakharov. Self-similarity of wind-driven seas. Nonl. Proc. Geophys., 12:891-946, 2005. [3] S. I. Badulin and V. E. Zakharov. New dissipation function for weakly turbulent wind-driven seas. ArXiv e-prints, (1212.0963), December 2012. [4] M. A. Donelan, J. Hamilton, and W. H. Hui. Directional spectra of wind-generated waves. Phil. Trans. Roy. Soc. Lond. A, 315:509-562, 1985. [5] M. A. Donelan and W. J. Pierson-jr. Radar scattering and equilibrium ranges in wind-generated waves with application to scatterometry. J. Geophys. Res., 92(C5):4971-5029, 1987. [6] E. Gagnaire-Renou, M. Benoit, and S. I. Badulin. On weakly turbulent scaling of wind sea in simulations of fetch-limited growth. J. Fluid Mech., 669:178-213, 2011. [7] R. L. Snyder, F. W. Dobson, J. A. Elliot, and R. B. Long. Array measurements of atmospheric pressure fluctuations above surface gravity waves. J. Fluid Mech., 102:1-59, 1981. [8] D. J. Webb. Non-linear transfers between sea waves. Deep Sea Res., 25:279-298, 1978. [9] V. E. Zakharov, D. Resio, and A. N. Pushkarev. New wind input term consistent with experimental, theoretical and numerical considerations. ArXiv e-prints, (1212.1069), December 2012.

  9. Impact of improved wave dissipation parameterisations on wave-current interactions in a coupled wave-ocean model

    NASA Astrophysics Data System (ADS)

    Hanafin, J. A.; Ardhuin, F.; Roland, A.; Leckler, F.; Rascle, N.

    2012-12-01

    The WAVEWATCH-III model is used operationally as part of the PREVIMER coastal forecast system. A global version of the model provides boundary conditions for a series of stand-alone high-resolution regional sub-domains, on unstructured grids, which are coupled with the regional ocean model MARS. New developments in the WW3 model include a combination of dissipation parameterisations (Ardhuin et al 2010). An anisotropic breaking-induced wind wave dissipation has been based on the local saturation spectrum, with a higher dissipation rate in the mean wave direction, designed to fit observed directional spreading. Additionally, a cumulative dissipation rate inspired by Babanin and Young (2005) but directly estimated from breaking wave probabilities dramatically enhances the dissipation at frequencies greater than 3 times the peak frequency. Regarding swell, a non-linear dissipation based on SAR-derived dissipation rates across the Pacific (Ardhuin et al., 2009) has been introduced. Validation of this model (Rascle and Ardhuin 2012, submitted) using a global hindcast from 1994-2010 shows improvements in significant wave height compared to an altimeter database, with values <10% in general. Regarding extreme events, Hanafin et al (2012) showed that the prediction of the timing of arrival, peak period and spectral distribution of very long swell generated by hurricane-level winds in the North Atlantic compared very well to coastal buoy observations. One of the aims of such improvements is to assist users by providing better geophysical parameters as output. Improvements noted in the mean squared slope compared to buoys, for example, implies a larger amount of energy is available to near-surface Langmuir turbulence. A recent study using the WW3 wave model and the MARS ocean model (Ardhuin et al, in press, JPO 2012) focused on near-shore wave interaction with strong currents. At small scales, rapid steepening of wave slopes by opposing currents induces enhanced breaking as the group velocity decreases. In the study area, tidal currents of up to 4m/s which are highly coherent over the water column and a high wind event created excellent conditions to test the performance of the model. A surface current radar with a resolution of 1km due to multiple signal classification algorithm and a number of buoys were used for validation. Adding currents in the wave model reduced the errors by up to 30% and clearly showed the effects of wave trapping by the strong tidal currents. Comparing different dissipation parameterisations, however, showed that none were completely satisfactory, indicating that further research is required in this area. For short wind waves, the relative wind at the air-sea interface becomes an important factor. At larger scales, waves are refracted by currents. In these cases, the choice of dissipation parameterisation was found to be less important when only one partition was present, though Ardhuin et al (2010) showed better results in mixed seas. Tidal modulations were shown to be due to currents, rather than water level, and a large impact was observed down-wave of currents that have large refraction effects as well as in the vicinity of the currents.

  10. Impact of planetary waves on ice-sheet evolution throughout the last glacial - interglacial cycle

    NASA Astrophysics Data System (ADS)

    Beghin, P.; Charbit, S.; Dumas, C.; Kageyama, M.; Roche, D. M.; Ritz, C.

    2012-04-01

    Planetary waves can be forced by azonal heating patterns due for example to land-sea contrast, by the topography or by transient eddies. A lot of studies have shown that orographic effect have a great impact on the evolution of ice sheets, and, in turn, that large continental ice masses strongly influence the stationary waves pattern . In general circulation models (GCMs), all these effects are explicitly represented through equations of dynamics but their influence cannot be studied separately. By contrast, in the climate model of intermediate complexity CLIMBER, planetary waves are parameterized as a function of the azonal component of sea-level pressure which depends (in our own version of the model) on the azonal sea-level temperature and the orography. It is therefore much simpler to investigate the influence of both thermal and orographic effects with this kind of model. The other great advantage of CLIMBER compared to GCMs is its small computational time. Moreover it has been coupled to the 3D thermo-mechanical ice-sheet model GRISLI and is therefore well suited for studies of climate-ice sheet interactions at the ~ 100 kyr time scale. Using the CLIMBER-GRISLI model, we investigate in this study the role of both thermal and orographic forcings on the evolution of past Northern hemisphere ice sheets. To achieve this goal, three types of parametrizations of planetary waves are tested and compared to our reference simulation (i.e. planetary waves are removed). The first one relies only on the thermal effect ; the second one only uses the orographic effect ; and the last one is a combination of both. Results are analysed in terms of temperature and accumulation pattern changes and their influence on the simulated climatic cycles. The choice of these parameterizations is shown to have a strong impact on the dynamics of the glaciation history.

  11. The 2002/2003 El Nio: Equatorial waves sequence and their impact on sea surface temperature

    E-print Network

    Paris-Sud XI, Université de

    The 2002/2003 El Niño: Equatorial waves sequence and their impact on sea surface temperature K/2003 El Nin~ o: Equatorial waves sequence and their impact on sea surface temperature, J. Geophys. Res (hereafter CP El Niño) or Modoki El Niño. CP El Niño consists in a warming of the sea surface temperature

  12. Impact force identification in aerospace panels by an inverse ultrasonic guided wave problem

    NASA Astrophysics Data System (ADS)

    Bartoli, Ivan; Salamone, Salvatore; Lanza di Scalea, Francesco; Rhymer, Jennifer; Kim, Hyonny

    2011-04-01

    This paper deals with monitoring impacts on aluminum and composite aerospace panels. The specific problems addressed are (1) the identification of the impact forces (force magnitude time history) and (2) the discrimination of "damaging impacts" from "non-damaging impacts." Ultrasonic guided waves generated by the impacts are used as the sensing mechanism. Flexible Macro-Fiber Composite (MFC) patches are used as the ultrasonic receivers. The impact force identification method is based on an optimization routine which minimizes the difference between the experimental impact waves and the numerical impact waves calculated by a Semi-Analytical Finite Element (SAFE) forced analysis. The differentiation of "damaging impacts" vs. "non-damaging impacts" is based on a frequency analysis of the impact waves. These techniques are demonstrated through an extensive experimental testing program involving the following six specimens: an aluminum panel, a quasi-isotropic CFRP composite panel, a highly anisotropic CFRP composite panel, a stiffened aluminum panel, a stiffened quasi-isotropic CFRP composite panel, and a stiffened anisotropic CFRP composite panel. These panels were subjected to low-velocity hammer impacts and to high-velocity gas-gun impacts by ice projectiles at speeds up to 170 m/sec using UCSD's gas-gun test facility. In all of these experiments, the techniques summarized above gave excellent results for both impact force identification and impact force discrimination.

  13. Impact of the wave number estimation in Underground Focusing SAR images

    Microsoft Academic Search

    Fernando Quivira; Jose Angel Martinez Lorenzo; Carey M. Rappaport

    2010-01-01

    This work studies the impact estimating soil wave number in Underground Focusing SAR imaging for tunnel detection applications. It is demonstrated that poor underground imaging results when wave refraction at the ground surface is neglected, but that incorporating refraction with sufficiently high estimates of soil dielectric constant produce clear target images. Using a wrong wave number for the soil incorrectly

  14. Assessing the impacts of changes in the Hadley Circulation on stationary Rossby wave propagation

    E-print Network

    Phipps, Steven J.

    Assessing the impacts of changes in the Hadley Circulation on stationary Rossby wave propagation A broadly organized into storm tracks and stationary Rossby waves. Through anomalous upper tropospheric divergence, modifications in the HC are connected to changes in the generation of Rossby waves that propagate

  15. Boundary conditions on internal three-body wave functions Kevin A. Mitchell and Robert G. Littlejohn

    E-print Network

    Mitchell, Kevin A.

    Boundary conditions on internal three-body wave functions Kevin A. Mitchell and Robert G and m quantum numbers may be expressed in terms of an internal wave function k l , which is a function and where k l , the ``internal wave func- tion,'' is a function of three internal or shape coordinates

  16. Application of wave distribution function methods to an ELF hiss event at high latitudes

    Microsoft Academic Search

    Ondrej Santolík; Michel Parrot

    2000-01-01

    Multicomponent waveform data are used to calculate wave polarization and propagation characteristics, with both simple plane wave methods and more general wave distribution function (WDF) techniques. The WDF techniques allow us to estimate a continuous distribution of wave energy with respect to the wave vector directions. We describe several newly developed analysis methods, and we compare their results with existing

  17. Estimating Moho depth utilizing S-wave receiver functions

    NASA Astrophysics Data System (ADS)

    Ceylan, S.; Rychert, C.; Harmon, N.

    2014-12-01

    H-k stacking method [Zhu and Kanamori, 2000] is a widely used grid search technique for estimating the Moho depth (H) and Vp/Vs (k) beneath a given station. The H-k surface reaches a maximum when the optimum H and k values are used, which is assumed to be the average crustal structure beneath the seismic station. In general, the method is employed in conjunction with P-wave receiver functions. Here, we investigate the usability of H-k stacking method with S-to-P (Sp) conversions and S-wave reverberations within the crust, employing an extended multi-taper deconvolution. We apply the method to southern California, using data recorded between 1990-2011. We compare results with those of prior studies that used P-to-S (Ps) conversions [Zhu and Kanamori, 2000; Yan and Clayton, 2007], applying a smoothing length of 0.5 degrees to reflect lateral Sp sensitivity. P-waves have better potential to resolve lateral variations in Moho depth owing to the higher frequency content and the geometry of Ps ray path. Our results from Sp conversions are in broad agreement with those from Ps, affirming that S-wave receiver functions can be used in conjunction with the H-k stacking method. Consistent with the P-wave receiver function results, crust is thinner beneath the central Transverse Range (30 km) with respect to eastern Transverse Range (33 km) and Peninsular Region (35 km). Our Moho depth observations (35 km) are more compatible with those of Yan and Clayton [2007] (~35 km) than Zhu and Kanamori [2000] (~30 km) beneath Sierra Nevada, most probably due to a larger data set this study and Yan and Clayton [2007] use. Also, results from this study are deeper than those from Ps for the Salton Trough (30-35 km vs. 25 km). In this case, broad receiver function waveform characteristics suggest a more gradual impedance change across the Moho discontinuity and/or a multi-layered crust. We suggest that a combination of P- and S-wave receiver functions can yield more robust crustal thickness estimates, providing additional constraints in areas where data coverage is not sufficient, Ps results become complicated due to multiple crustal layers, or velocity gradients are gradual.

  18. Theory of steady-state plane tunneling-assisted impact ionization waves

    SciTech Connect

    Kyuregyan, A. S., E-mail: ask@vei.ru [Lenin All-Russian Electrical-Engineering Institute (Russian Federation)

    2013-07-15

    The effect of band-to-band and trap-assisted tunneling on the properties of steady-state plane ionization waves in p{sup +}-n-n{sup +} structures is theoretically analyzed. It is shown that such tunneling-assisted impact ionization waves do not differ in a qualitative sense from ordinary impact ionization waves propagating due to the avalanche multiplication of uniformly distributed seed electrons and holes. The quantitative differences of tunneling-assisted impact ionization waves from impact ionization waves are reduced to a slightly different relation between the wave velocity u and the maximum field strength E{sub M} at the front. It is shown that disregarding impact ionization does not exclude the possibility of the existence of tunneling-assisted ionization waves; however, their structure radically changes, and their velocity strongly decreases for the same E{sub M}. A comparison of the dependences u(E{sub M}) for various ionization-wave types makes it possible to determine the conditions under which one of them is dominant. In conclusion, unresolved problems concerning the theory of tunneling-assisted impact ionization waves are discussed and the directions of further studies are outlined.

  19. No-boundary wave function for two-field inflation

    NASA Astrophysics Data System (ADS)

    Hwang, Dong-il; Kim, Soo A.; Yeom, Dong-han

    2015-06-01

    In this paper, we investigate the no-boundary wave function and the complex-valued instantons for two-field inflation models that have different masses. If there is a relatively massive direction, to classicalize the massive field, the solution should start from the slow direction with relatively larger vacuum energy. Therefore, the existence of the massive direction implies the increase of expected e-foldings. The most probable e-foldings are approximately N? {{({{m}2}/{{m}1})}2}× O(1) in the {{m}1}\\ll {{m}2} limit. Therefore, as long as there is a sufficient mass hierarchy, the no-boundary wave function can reasonably explain large e-foldings, so to speak, more than 50 e-foldings.

  20. Exact wave functions for atomic electron interacting with photon fields

    NASA Astrophysics Data System (ADS)

    Guo, Dong-Sheng

    2013-02-01

    Many nonlinear quantum optical physics phenomena need more accurate wave functions and corresponding energy or quasienergy levels to account for. An analytic expression of wave functions with corresponding energy levels for an atomic electron interacting with a photon field is presented as an exact solution to the Schrödinger-like equation involved with both atomic Coulomb interaction and electron-photon interaction. The solution is a natural generalization of the quantum-field Volkov states for an otherwise free electron interacting with a photon field. The solution shows that an Nlevel atom in light form stationary states without extra energy splitting in addition to the Floquet mechanism. The treatment developed here with computing codes can be conveniently transferred to quantum optics in classical-field version as research tools to benefit the whole physics community.

  1. Horizon Wave-Function and the Quantum Cosmic Censorship

    E-print Network

    Casadio, Roberto; Stojkovic, Dejan

    2015-01-01

    We investigate the Cosmic Censorship Conjecture by means of the horizon wave-function (HWF) formalism. We consider a charged massive particle whose quantum mechanical state is represented by a spherically symmetric Gaussian wave-function, and restrict our attention to the superxtremal case (with charge-to-mass ratio $\\alpha>1$), which is the prototype of a naked singularity in the classical theory. We find that one can still obtain a normalisable HWF for $\\alpha^2 2$, and the uncertainty in the location of the horizon blows up at $\\alpha^2=2$, signalling that such an object is no more well-defined. This perhaps implies that a {\\em quantum\\/} Cosmic Censorhip might be conjectured by stating that no black holes with charge-to-mass ratio greater than a critical value (of the order of $\\sqrt{2}$) can exist.

  2. Semiclassical wave functions and energy spectra in polygon billiards

    E-print Network

    Stefan Giller

    2014-12-01

    A consistent scheme of semiclassical quantization in polygon billiards by wave function formalism is presented. It is argued that it is in the spirit of the semiclassical wave function formalism to make necessary rationalization of respective quantities accompanied the procedure of the semiclassical quantization in polygon billiards. Unfolding rational polygon billiards (RPB) into corresponding Riemann surfaces (RS) periodic structures of the latter are demonstrated with 2g independent periods on the respective multitori with g as their genuses. However it is the two dimensional real space of the real linear combinations of these periods which is used for quantizing RPB. A class of doubly rational polygon billiards (DRPB) is distinguished for which these real linear relations are rational and their semiclassical quantization by wave function formalism is presented. It is shown that semiclassical quantization of both the classical momenta and the energy spectra are determined completely by periodic structure of the corresponding RS. Each RS is then reduced to elementary polygon patterns (EPP) as its basic periodic elements. Each such EPP can be glued to a torus of genus g. Semiclassical wave functions (SWF) are then constructed on EPP. The SWF for DRPB appear to be exact. They satisfy the Dirichlet, the Neumannn or the mixed boundary conditions. Not every mixing is allowed however and a respective incompleteness of SWF is discussed. Dens families of DRPB are used for approximate semiclassical quantization of RPB. General rational polygons are quantized by approximating them by DRPB. An extension of the formalism to irrational polygons is described as well. The semiclassical approximations constructed in the paper are controlled by general criteria of the eigenvalue theory. A relation between the superscar solutions and SWF constructed in the paper is also discussed.

  3. Interaction between light and matter: a photon wave function approach

    NASA Astrophysics Data System (ADS)

    Saldanha, Pablo L.; Monken, C. H.

    2011-07-01

    The Bialynicki-Birula-Sipe photon wave function formalism is extended to include the interaction between photons and continuous non-absorptive media. When the second quantization of this formalism is introduced, a new method for describing the quantum interactions between light and matter emerges. As an example of the application of the method, an expression for the quantum state of the twin photons generated by parametric downconversion is derived in agreement with previous treatments, but with a more intuitive interpretation.

  4. Wave functions for the hydrogen molecule and molecule ion

    Microsoft Academic Search

    H. C. Bowen; J. W. Linnett

    1963-01-01

    Calculations have been carried out using wave functions for H2+ and H2 in which polarization of the atomic 1s orbitals is achieved by combining them with off-centre 1s-type orbitals. It is found that for both species the use of this method is not worth while compared with the employment of 2p-type orbitals. This agrees with the conclusions of Geller et

  5. Wave functions for the hydrogen molecule and molecule ion

    Microsoft Academic Search

    H. C. Bowen; J. W. Linnett

    1963-01-01

    Calculations have been carried out using wave functions for H2 and H2 in which polarization of the atomic 1s orbitals is achieved by combining them with off-centre 1s-type orbitals. It is found that for both species the use of this method is not worth while compared with the employment of 2p-type orbitals. This agrees with the conclusions of Geller et

  6. IMPACTS OF URBANIZATION ON WATERSHED HYDROLOGIC FUNCTION

    EPA Science Inventory

    Although urbanization has a major impact on watershed hydrology, there have not been studies to quantify basic hydrological relationships that are altered by the addition of impervious surfaces. The USDA-ARS and USEPA-ORD-NRMRL have initiated a pilot program to study the impacts...

  7. Hydrodynamic Waves and Correlation Functions in Dusty Plasmas

    NASA Astrophysics Data System (ADS)

    Bhattacharjee, A.; Wang, Xiaogang

    1997-11-01

    A hydrodynamic description of strongly coupled dusty plasmas is given when physical quantities vary slowly in space and time and the system can be assumed to be in local thermodynamic equilibrium. The linear waves in such a system are analyzed. In particular, a dispersion equation is derived for low-frequency dust acoustic waves, including collisional damping effects, and compared with experimental results. The linear response of the system is calculated from the fluctuation-dissipation theorem and the hydrodynamic equations. The requirement that these two calculations coincide constrains the particle correlation function for slowly varying perturbations [L. P. Kadanoff and P. C. Martin, Ann. Phys. 24, 419 (1963)]. It is shown that in the presence of the slow dust-acoustic waves, the dust auto-correlation function is of the Debye-Hekel form and the shielding distance is the dust Debye length. In the short-wavelength regime, an integral equation is derived from kinetic theory and solved numerically to yield particle correlation functions that display ``liquid-like'' behavior and have been observed experimentally [R. A.. Quinn, C. Cui, J. Goree, J. B. Pieper, H. Thomas and G. E. Morfill, Phys. Rev. E 53, R2049 (1996)].

  8. Propagation of vortex electron wave functions in a magnetic field

    NASA Astrophysics Data System (ADS)

    Gallatin, Gregg M.; McMorran, Ben

    2012-07-01

    The physics of coherent beams of photons carrying axial orbital angular momentum (OAM) is well understood, and such beams, sometimes known as vortex beams, have found applications in optics and microscopy. Recently electron beams carrying very large values of axial OAM have been generated. In the absence of coupling to an external electromagnetic field, the propagation of such vortex electron beams is virtually identical mathematically to that of vortex photon beams propagating in a medium with a homogeneous index of refraction. But when coupled to an external electromagnetic field, the propagation of vortex electron beams is distinctly different from photons. Here we use the exact path integral solution to Schrodinger's equation to examine the time evolution of an electron wave function carrying axial OAM. Interestingly we find that the nonzero OAM wave function can be obtained from the zero OAM wave function, in the case considered here, simply by multipling it by an appropriate time and position dependent prefactor. Hence adding OAM and propagating it can in this case be replaced by first propagating then adding OAM. Also, the results shown provide an explicit illustration of the fact that the gyromagnetic ratio for OAM is unity. We also propose a novel version of the Bohm-Aharonov effect using vortex electron beams.

  9. Propagation of Vortex Electron Wave Functions in a Magnetic Field

    E-print Network

    Gregg M. Gallatin; Ben McMorran

    2012-02-24

    The physics of coherent beams of photons carrying axial orbital angular momentum (OAM) is well understood and such beams, sometimes known as vortex beams, have found applications in optics and microscopy. Recently electron beams carrying very large values of axial OAM have been generated. In the absence of coupling to an external electromagnetic field the propagation of such vortex electron beams is virtually identical mathematically to that of vortex photon beams propagating in a medium with a homogeneous index of refraction. But when coupled to an external electromagnetic field the propagation of vortex electron beams is distinctly different from photons. Here we use the exact path integral solution to Schrodingers equation to examine the time evolution of an electron wave function carrying axial OAM. Interestingly we find that the nonzero OAM wave function can be obtained from the zero OAM wave function, in the case considered here, simply by multipling it by an appropriate time and position dependent prefactor. Hence adding OAM and propagating can in this case be replaced by first propagating then adding OAM. Also, the results shown provide an explicit illustration of the fact that the gyromagnetic ratio for OAM is unity. We also propose a novel version of the Bohm-Aharonov effect using vortex electron beams.

  10. Resummation of rapidity logarithms in $B$ meson wave functions

    E-print Network

    Hsiang-nan Li; Yue-Long Shen; Yu-Ming Wang

    2013-01-03

    We construct an evolution equation for the $B$ meson wave functions in the $k_T$ factorization theorem, whose solutions sum the double logarithms associated with the light-cone singularities, namely, the rapidity logarithms. The derivation is subtler than that of the Sudakov resummation for an energetic light hadron, due to the involvement of the effective heavy-quark field. The renormalization-group evolution in the factorization scale needs to be included in order to derive an ultraviolet-finite and scale-invariant kernel for resumming the rapidity logarithms. It is observed that this kernel is similar to that of the joint resummation for QCD processes in extreme kinematic regions, which combines the threshold and $k_T$ resummations. We show that the resummation effect maintains the normalization of the $B$ meson wave functions, and strengths their convergent behavior at small spectator momentum. The resummation improved $B$ meson wave functions are then employed in the leading-order analysis of the $B\\to\\pi$ transition form factors, which lead to approximately 25% deduction in the large recoil region.

  11. Wave Propagation Experiments On Ballistically Impacted Composite Laminates

    Microsoft Academic Search

    Nobuo Takeda; Robert L. Sierakowski; Lawrence E. Malvern

    1981-01-01

    The details of the time history of the elastic waves in ballistically im pacted composite laminates have been obtained by using surface and em bedded strain gages. Records show that a very low-amplitude in-plane tensile wave arrives first followed by a medium-amplitude flexural wave and then a high-amplitude flexural wave. Measured and calculated values of wave speeds agree well.

  12. Measurement of the photon light-cone wave function by diffractive dissociation

    NASA Astrophysics Data System (ADS)

    Ashery, Daniel

    2006-11-01

    The measurement of the pion light-cone wave function is revisited and results for the Gegenbauer coefficients are presented. Mesurements of the photon electromagnetic and hadronic wave functions are described and results are presented.

  13. Measurement of the Pion and Photon Light-Cone Wave Functions by Diffractive Dissociation

    E-print Network

    Daniel Ashery

    2005-11-24

    The measurement of the pion light-cone wave function is revisited and results for the Gegenbauer coefficients are presented. Mesurements of the photon electromagnetic and hadronic wave functions are described and results are presented.

  14. Statistical properties and correlation functions for drift waves

    NASA Technical Reports Server (NTRS)

    Horton, W.

    1986-01-01

    The dissipative one-field drift wave equation is solved using the pseudospectral method to generate steady-state fluctuations. The fluctuations are analyzed in terms of space-time correlation functions and modal probability distributions. Nearly Gaussian statistics and exponential decay of the two-time correlation functions occur in the presence of electron dissipation, while in the absence of electron dissipation long-lived vortical structures occur. Formulas from renormalized, Markovianized statistical turbulence theory are given in a local approximation to interpret the dissipative turbulence.

  15. Restatement of conventional electronic wave function determination as a density functional procedure @fa@f)

    Microsoft Academic Search

    Marc R. Nyden; Robert G. Parr

    1983-01-01

    It is shown how any conventional ground-state electronic wave function determination starting from a basis set of orthonormal spatial orbitals fk may be restated as a density functional procedure. Write fk=(&rgr;\\/N)1\\/2exp(i?k), with &rgr; the total electron density, N the number of electrons, and ?k a function which may have complex as well as real parts. All matrix elements then are

  16. Optimization of quantum Monte Carlo wave functions using analytical energy derivatives

    E-print Network

    Lin, Xi

    Optimization of quantum Monte Carlo wave functions using analytical energy derivatives Xi Lin of the local energy, H^ / .5 If the wave function were the exact ground eigenstate, the local energy would November 1999 An algorithm is proposed to optimize quantum Monte Carlo QMC wave functions based on Newton

  17. Compressive Direct Measurement of the Quantum Wave Function Mohammad Mirhosseini,1,*

    E-print Network

    Boyd, Robert W.

    Compressive Direct Measurement of the Quantum Wave Function Mohammad Mirhosseini,1,* Omar S. Magaña) The direct measurement of a complex wave function has been recently realized by using weak values spatial wave function of photons. The procedure involves weak measurements of random projection operators

  18. The impact of heat waves on children's health: a systematic review.

    PubMed

    Xu, Zhiwei; Sheffield, Perry E; Su, Hong; Wang, Xiaoyu; Bi, Yan; Tong, Shilu

    2014-03-01

    Young children are thought to be particularly sensitive to heat waves, but relatively less research attention has been paid to this field to date. A systematic review was conducted to elucidate the relationship between heat waves and children's health. Literature published up to August 2012 were identified using the following MeSH terms and keywords: "heatwave", "heat wave", "child health", "morbidity", "hospital admission", "emergency department visit", "family practice", "primary health care", "death" and "mortality". Of the 628 publications identified, 12 met the selection criteria. The existing literature does not consistently suggest that mortality among children increases significantly during heat waves, even though infants were associated with more heat-related deaths. Exposure to heat waves in the perinatal period may pose a threat to children's health. Pediatric diseases or conditions associated with heat waves include renal disease, respiratory disease, electrolyte imbalance and fever. Future research should focus on how to develop a consistent definition of a heat wave from a children's health perspective, identifying the best measure of children's exposure to heat waves, exploring sensitive outcome measures to quantify the impact of heat waves on children, evaluating the possible impacts of heat waves on children's birth outcomes, and understanding the differences in vulnerability to heat waves among children of different ages and from different income countries. Projection of the children's disease burden caused by heat waves under climate change scenarios, and development of effective heat wave mitigation and adaptation strategies that incorporate other child protective health measures, are also strongly recommended. PMID:23525899

  19. Excitation of Jovian seismic waves by the Shoemaker-Levy 9 cometary impact

    NASA Astrophysics Data System (ADS)

    Lognonne, P.; Mosser, B.; Dahlen, F. A.

    1994-08-01

    The kinetic energy released by the collision of the comet Shoemaker-Levy 9 with Jupiter is expected to be between 1020 J and 1023 J. This energy will excite seismic waves, which will propagate within Jupiter. These seismic waves are computed by summing normal modes of degree l up to 1400 and frequency nu up to 10 mHz. The excitation amplitudes are obtained using a model of the blast wave induced by the explosion of the comet. Keeping in mind the possible detection of the waves with an IR camera, we examine the thermal signature of the global modes and transient waves excited by the impact. We show that the excitation of surface waves and normal modes will produce a directly observable signal for strong impacts only. An impact with an energy greater than 2.8 x 1021 J will produce a 10-mHz frequency P wave with associated peak-to-peak temperature fluctuations greater than 0.01 K at the antipode. Surface waves with frequencies less than 3 mHz will give rise to fluctuations everywhere in excess of 0.01 K for impacts greater than 9 x 1022 J. Lower energy impacts will not be directly detectable, the signal-to-noise ratio on a single pixel of the camera being too low. Stacking methods might enable the detection of P waves generated by impacts with energies as low as 7.25 x 1020 J at Delta = 90 deg and of surface waves generated by impacts as low as 1.4 x 1021 J. High-frequency monitoring of the temperature in the jovian troposphere during at least 2 hr after each impact, and low-frequency monitoring during the remaining observation time may provide unique information on the inner structure of Jupiter, including the core and the discontinuity due to the possible plasma phase transition of hydrogen.

  20. Impact damage detection in sandwich composite structures using Lamb waves and laser vibrometry

    NASA Astrophysics Data System (ADS)

    Lamboul, B.; Passilly, B.; Roche, J.-M.; Osmont, D.

    2013-01-01

    This experimental study explores the feasibility of impact damage detection in composite sandwich structures using Lamb wave excitation and signals acquired with a laser Doppler vibrometer. Energy maps are computed from the transient velocity wave fields and used to highlight defect areas in impacted coupons of foam core and honeycomb core sandwich materials. The technique performs well for the detection of barely visible damage in this type of material, and is shown to be robust in the presence of wave reverberation. Defect extent information is not always readily retrieved from the obtained defect signatures, which depend on the wave - defect interaction mechanisms.

  1. Ramp wave generation using graded areal density ceramic flyers and the plate impact technique

    NASA Astrophysics Data System (ADS)

    Taylor, P.; Goff, M.; Hazell, P. J.; Leighs, J.; Wood, D.; Appleby-Thomas, G. J.

    2014-05-01

    A requirement exists to generate realistic insults in energetic targets, for example ramp loadings leading to shock waves. This paper examines the development of a ceramic flyer ramp wave generation technique. Ceramic stereolithography was used to produce fully-dense, graded areal density alumina ceramic flyers. These flyers consisted of multiple square pyramids arranged on a solid base. The gas gun plate impact and electromagnetic particle velocity gauge techniques were used to observe the ramp waves generated when the flyers impacted a Kel-F 81 polymer target. Ramp waves of varying properties were successfully generated in the targets, and good agreement was obtained with 3D hydrocode modelling.

  2. Crustal structure of the Gamburtsev Mountains, East Antarctica, from S-wave receiver functions and Rayleigh wave phase velocities

    E-print Network

    Crustal structure of the Gamburtsev Mountains, East Antarctica, from S-wave receiver functions der Hilst Keywords: Gamburtsev Mountains Antarctica crustal structure S-wave receiver functions The Gamburtsev Subglacial Mountains (GSM), located in central East Antarctica, are one of the most enigmatic

  3. Climate change impact on wave energy in the Persian Gulf

    NASA Astrophysics Data System (ADS)

    Kamranzad, Bahareh; Etemad-Shahidi, Amir; Chegini, Vahid; Yeganeh-Bakhtiary, Abbas

    2015-06-01

    Excessive usage of fossil fuels and high emission of greenhouse gases have increased the earth's temperature, and consequently have changed the patterns of natural phenomena such as wind speed, wave height, etc. Renewable energy resources are ideal alternatives to reduce the negative effects of increasing greenhouse gases emission and climate change. However, these energy sources are also sensitive to changing climate. In this study, the effect of climate change on wave energy in the Persian Gulf is investigated. For this purpose, future wind data obtained from CGCM3.1 model were downscaled using a hybrid approach and modification factors were computed based on local wind data (ECMWF) and applied to control and future CGCM3.1 wind data. Downscaled wind data was used to generate the wave characteristics in the future based on A2, B1, and A1B scenarios, while ECMWF wind field was used to generate the wave characteristics in the control period. The results of these two 30-yearly wave modelings using SWAN model showed that the average wave power changes slightly in the future. Assessment of wave power spatial distribution showed that the reduction of the average wave power is more in the middle parts of the Persian Gulf. Investigation of wave power distribution in two coastal stations (Boushehr and Assalouyeh ports) indicated that the annual wave energy will decrease in both stations while the wave power distribution for different intervals of significant wave height and peak period will also change in Assalouyeh according to all scenarios.

  4. The impact energy of a moored tanker under the action of regular waves

    SciTech Connect

    Yu-Cheng Li

    1982-09-01

    The influence that factors such as mooring line conditions, fender arrangements, dolphin arrangements, degree of ship loading, waves of long period, wave direction, and wind on the impact energy of a moored tanker were studied. Based on systematic test data, a semi-empirical formula was developed to calculate the impact energy of the moored ship on the berthing facilities under the action of regular waves. It was shown by experiment that this method is suitable for calculating the impact energy of moored ships of capacities as great as 200 X 10/sup 3/ t.

  5. Impact of Stone Removal on Renal Function: A Review

    PubMed Central

    Wood, Kyle; Keys, Tristan; Mufarrij, Patrick; Assimos, Dean G

    2011-01-01

    Stone removal can improve renal function by eradicating obstruction and, in certain cases, an underlying infection. Stone-removing procedures, however, may negatively impact functional integrity. Many things may impact the latter, including the procedures used, the methods of assessing function, the time when these assessments are made, the occurrence of complications, the baseline condition of the kidney, and patient-related factors. In the majority of cases, little significant functional impairment occurs. However, there are gaps in our knowledge of this subject, including the cumulative effects of multiple procedures violating the renal parenchyma and long-term functional outcomes. PMID:21935339

  6. A Critical Examination of Wind-Wave Spectral Functional Form

    NASA Technical Reports Server (NTRS)

    Huang, Norden E.; Long, Steven R.

    1999-01-01

    Traditionally, data from random ocean waves are presented in spectral functions. The spectra are the result of Fourier analysis. Fourier spectral analysis has dominated data analysis for, at least, the last hundred years. It has been the standard method for is examining the global amplitude-frequency distributions. Although Fourier transform valid under extremely general conditions, there are some crucial restrictions for the Fourier spectral analysis. The system must be linear, and the data must be stationary- otherwise, the resulting spectrum will make little physical sense. The stationarity requirement is also a common required criterion for most of other available data analysis methods. Nevertheless, few, if any, natural phenomena are linear and stationary. To compound these complications is the imperfection of our probes or numerical schemes the interactions of the imperfect probes even with a perfect linear system can make the final data nonlinear. Furthermore, all the available data are usually of finite duration. Under these conditions, Fourier analysis is of limited use, For lack of alternatives, however, Fourier analysis is still used to process such data. The loose application of Fourier analysis and the insouciant adoption of the stationary and linear assumptions may lead to misleading conclusions. Ocean waves are know to be nonlinear, and the wind system generating the wave field are seldom stationary- As a result, the traditional examination of the spectral form hardly made physical sense. A new method for analyzing nonlinear and nonstationary data has been developed. The key part is the Empirical Mode Decomposition (EMD) method with which any complicated data set can be decomposed into a finite and often small number of Intrinsic Mode Functions (IMF) that serve as the basis of the representation of the data, This decomposition method is adaptive, and, therefore, highly efficient. The IMFs admit well-behaved Hilbert transforms, and yield instantaneous energy and frequency as functions of time that give sharp identifications of imbedded structures. The final presentation of the results is an energy-frequency-time distribution, designated as the Hilbert Spectrum. Among the main conceptual innovations is the introduction of the instantaneous frequencies for complicated data sets, which eliminate the need of spurious harmonics to represent nonlinear and nonstationary signals. The spectral forms of the ocean waves are very different. This new method offers the first physical meaningful view of the wave spectrum. Data from laboratory and field will be presented to illustrate the differences.

  7. New forms of deuteron equations and wave function representations

    SciTech Connect

    Fachruddin, I.; Elster, Ch.; Glo''ckle, W.

    2001-05-01

    A recently developed helicity basis for nucleon-nucleon (NN) scattering is applied to the deuteron bound state. Here the total spin of the deuteron is treated in such a helicity representation. For the bound state, two sets of two coupled eigenvalue equations are developed, where the amplitudes depend on two variables and one variable, respectively. Numerical illustrations based on the realistic Bonn-B NN potential are given. In addition, an ''operator form'' of the deuteron wave function is presented, and several momentum dependent spin densities are derived and shown, in which the angular dependence is given analytically.

  8. Wave Function Structure in Two-Body Random Matrix Ensembles

    E-print Network

    Kaplan, L; Kaplan, Lev; Papenbrock, Thomas

    2000-01-01

    We study the structure of eigenstates in two-body interaction random matrix ensembles and find significant deviations from random matrix theory expectations. The deviations are most prominent in the tails of the spectral density and indicate localization of the eigenstates in Fock space. Using ideas related to scar theory we derive an analytical formula that relates fluctuations in wave function intensities to fluctuations of the two-body interaction matrix elements. Numerical results for many-body fermion systems agree well with the theoretical predictions.

  9. Is spontaneous wave function collapse testable at all?

    E-print Network

    Lajos Diósi

    2015-03-16

    Mainstream literature on spontaneous wave function collapse never reflects on or profit from the formal coincidence and conceptual relationship with standard collapse under time-continuous quantum measurement (monitoring). I propose some easy lessons of standard monitoring theory which would make spontaneous collapse models revise some of their claims. In particular, the objective detection of spontaneous collapse remains impossible as long as the correct identification of what corresponds to the signal in standard monitoring is missing from spontaneous collapse models, the physical detectability of the "signal" is not stated explicitly and, finally, the principles of physical detection are not revealed.

  10. Special relativity, EPR, and the collapse of the wave function

    NASA Astrophysics Data System (ADS)

    Socolovsky, M.

    2003-05-01

    We discuss a paradox which appears in EPR experiments when the collapse of the wave function is analyzed in moving reference frames: the collapse can occur before the actual measurement of the spin component (or polarization) of one of the particles. We show that the paradox can be solved using the instantaneity of the reduction process in all reference frames. Using the same concept, we illustrate with an example the impossibility of defining, in certain circumstances, a covariant state vector in all regions of space-time.

  11. Impact of Parent Training on Family Functioning.

    ERIC Educational Resources Information Center

    Adams, Jerome F.

    2001-01-01

    Examines outcomes of a Systematic Training for Effective Parenting program in several areas of family functioning identified by the McMaster model of family health. Finds that participants who completed the parent training did report more improvements in general family functioning than those parents whose children received routine mental health…

  12. Propagation of shock waves in elastic solids caused by cavitation microjet impact. I: Theoretical formulation.

    PubMed

    Zhong, P; Chuong, C J

    1993-07-01

    To understand the physical process of the impingement of cavitation microjet and the resultant shock wave propagation in an elastic solid, a theoretical model using geometrical acoustics was developed. Shock waves induced in both the jet head (water) and the solid were analyzed during a tri-supersonic impact configuration when the contact edge between the jet head and the elastic boundary expands faster than the longitudinal wave speed in the solid. Impact pressure at the boundary was solved using continuity conditions along the boundary normal. Reflection and refraction of shock waves from a solid-water interface were also included in the model. With this model, the impact pressure at the solid boundary and the stress, strain as well as velocity discontinuities at the propagating shock fronts were calculated. A comparison with results from previous studies shows that this model provides a more complete and general solution for the jet impact problem. PMID:8354758

  13. A compliant-hull concept for planning craft wave-impact shock reduction

    Microsoft Academic Search

    William S. Vorus

    2004-01-01

    The subject of this paper is analysis of high-speed planing-craft wave impact, with the inclusion of hull-surface compliance. The analysis methods were extended in an effort to develop compliant-surface technology for wave-impact shock reduction. The practical outcome of this work, along with experimental cylinder drop-test evaluations, have been reported previously. The overall technology developed is composed of compliant plates over

  14. Determination of wave growth from measured distribution functions and transport theory

    Microsoft Academic Search

    C. T. Dum; E. Marsch; W. Pilipp

    1980-01-01

    A stability analysis which directly uses particle distribution functions determined from experiments or transport theory, rather than model distributions, is carried out. The features of distribution functions relevant to whistlers, ion cyclotron waves, including their low-frequency extensions for propagation along the magnetic field, and to ion-acoustic waves are analyzed in detail. The dependence of wave growth on the precise shape

  15. Extracting the Green's function of attenuating heterogeneous acoustic media from uncorrelated waves

    Microsoft Academic Search

    Roel Snieder

    2007-01-01

    The Green's function of acoustic or elastic wave propagation can, for loss-less media, be retrieved by correlating the wave field that is excited by random sources and is recorded at two locations. Here the generalization of this idea to attenuating acoustic waves in an inhomogeneous medium is addressed, and it is shown that the Green's function can be retrieved from

  16. Heat waves in Romania. Regional features, changes and estimated impact

    NASA Astrophysics Data System (ADS)

    Croitoru, Adina-Eliza

    2015-04-01

    Climate changes, including changes in extreme weather events, have currently become one of the major social, economic and environmental threats. The main aim of this study is to present the spatio-temporal features and changes that occurred in heat waves in Romania over a period of 53 years: 1961-2013. The identification of heat waves was made considering the maximum daily temperature data series recorded in 22 weather stations based on the 95th percentile threshold, and a minimum duration of three consecutive days. Four parameters of the heat waves were considered for further analysis: heat waves number, heat waves day frequency, heat waves mean duration, and heat waves maximum duration. The main results are: the most numerous and the longest heat waves are specific to the Southern and Western regions of Romania, while the less and the shortest ones were recorded in the Southeast part of the country; in terms of trends, most of the slopes calculated are positive and the great majority of weather stations recorded increasing trends to all heat waves parameters (77-95 %) and more than 70 % of the slopes were found statistically significant.

  17. Gas filtration during the impact of weak shock waves on granular layers

    Microsoft Academic Search

    A. Britan; G. Ben-Dor; T. Elperin; O. Igra; J. P. Jiang

    1997-01-01

    This paper deals with the unsteady gas filtration through a granular layer attached to a rigid end-wall when impacted head-on by a weak shock wave in a shock tube. The main goal of the present work is to study the gas pressure field developed inside the granular layer during its compression by the shock wave. A physical model is proposed

  18. Horizon wave-function and the quantum cosmic censorship

    NASA Astrophysics Data System (ADS)

    Casadio, Roberto; Micu, Octavian; Stojkovic, Dejan

    2015-07-01

    We investigate the Cosmic Censorship Conjecture by means of the horizon wave-function (HWF) formalism. We consider a charged massive particle whose quantum mechanical state is represented by a spherically symmetric Gaussian wave-function, and restrict our attention to the superextremal case (with charge-to-mass ratio ? > 1), which is the prototype of a naked singularity in the classical theory. We find that one can still obtain a normalisable HWF for ?2 < 2, and this configuration has a non-vanishing probability of being a black hole, thus extending the classically allowed region for a charged black hole. However, the HWF is not normalisable for ?2 > 2, and the uncertainty in the location of the horizon blows up at ?2 = 2, signalling that such an object is no more well-defined. This perhaps implies that a quantum Cosmic Censorship might be conjectured by stating that no black holes with charge-to-mass ratio greater than a critical value (of the order of ?{ 2}) can exist.

  19. Photon wave function: A covariant formulation and equivalence with QED

    NASA Astrophysics Data System (ADS)

    Tamburini, F.; Vicino, D.

    2008-11-01

    We discuss the limits of the photon wave function (PWF) formalism, which is experiencing a revival these days as a result of new practical applications in photonics and quantum optics. We build a Dirac-like equation for the PWF written in a manifestly covariant form and show that, in the presence of charged matter fields, it reproduces the standard formulation of (classical) electrodynamics. This shows that attempts to construct a full quantum theory of interacting photons (mutually or interacting with matter) based on the so-called photon wave function approach can lead only to results already described by standard quantum electrodynamics (QED). The PWF formalism can then be used only to provide an easier description of some particular situations—for example, the propagation of free photons or photons propagating in a medium as described in Bialynicki-Birula [in Progress in Optics, edited by E. Wolf (Elsevier, Amsterdam, 1996), pp. 245-294] especially when the photon number remains fixed in time but not to replace QED in toto.

  20. Pineal Function: Impact of Microarray Analysis

    PubMed Central

    Klein, David C.; Bailey, Michael J.; Carter, David A.; Kim, Jong-so; Shi, Qiong; Ho, Anthony; Chik, Constance; Gaildrat, Pascaline; Morin, Fabrice; Ganguly, Surajit; Rath, Martin F.; Møller, Morten; Sugden, David; Rangel, Zoila G.; Munson, Peter J.; Weller, Joan L.; Coon, Steven L.

    2009-01-01

    Microarray analysis has provided a new understanding of pineal function by identifying genes that are highly expressed in this tissue relative to other tissues and also by identifying over 600 genes that are expressed on a 24-hour schedule. This effort has highlighted surprising similarity to the retina and has provided reason to explore new avenues of study including intracellular signaling, signal transduction, transcriptional cascades, thyroid/retinoic acid hormone signaling, metal biology, RNA splicing, and the role the pineal gland plays in the immune/inflammation response. The new foundation that microarray analysis has provided will broadly support future research on pineal function. PMID:19622385

  1. Impact of Exotic Invertebrate Invaders on Food Web Structure and Function in the Great Lakes: a Network Analysis Approach

    E-print Network

    Impact of Exotic Invertebrate Invaders on Food Web Structure and Function in the Great Lakes a second wave of species invasions dominated by exotic invertebrates- Zebra mussels (Dreissena polymorpha invasions (e.g., sea Lamprey and Alewife), these invertebrates inserted themselves in the lower trophic

  2. Pulse wave velocity and cognitive function in older adults.

    PubMed

    Zhong, Wenjun; Cruickshanks, Karen J; Schubert, Carla R; Carlsson, Cynthia M; Chappell, Richard J; Klein, Barbara E K; Klein, Ronald; Acher, Charles W

    2014-01-01

    Arterial stiffness may be associated with cognitive function. In this study, pulse wave velocity (PWV) was measured from the carotid to femoral (CF-PWV) and from the carotid to radial (CR-PWV) with the Complior SP System. Cognitive function was measured by 6 tests of executive function, psychomotor speed, memory, and language fluency. A total of 1433 participants were included (mean age 75 y, 43% men). Adjusting for age, sex, education, pulse rate, hemoglobin A1C, high-density lipoprotein cholesterol, hypertension, cardiovascular disease history, smoking, drinking, and depression symptoms, a CF-PWV>12 m/s was associated with a lower Mini-Mental State Examination score (coefficient: -0.31, SE: 0.11, P=0.005), fewer words recalled on Auditory Verbal Learning Test (coefficient: -1.10, SE: 0.43, P=0.01), and lower score on the composite cognition score (coefficient: -0.10, SE: 0.05, P=0.04) and marginally significantly associated with longer time to complete Trail Making Test-part B (coefficient: 6.30, SE: 3.41, P=0.06), CF-PWV was not associated with Trail Making Test-part A, Digit Symbol Substation Test, or Verbal Fluency Test. No associations were found between CR-PWV and cognitive performance measures. Higher large artery stiffness was associated with worse cognitive function, and longitudinal studies are needed to confirm these associations. PMID:23632267

  3. Hormonal profile impact on female sexual function in young women

    NASA Astrophysics Data System (ADS)

    Stoian, Dana; Craciunescu, Mihalea; Craina, Marius; Pater, Liana; Pater, Flavius

    2014-12-01

    Female sexual function is dependent, in physiological milieu upon hormonal impulses: estradiol, testosterone, cortisol, progesterone, prolactin and TSH. Out study tries to appreciate the impact of testosterone, estradiol and prolactin, the major hormones involved in the sexual response, on the normal sexual function. This parameter is approximated by the value of the total FSFI score, a validated international structured interview.

  4. The effect of wave function orthogonality on the simultaneous ionization and excitation of helium

    NASA Astrophysics Data System (ADS)

    Liu, Li-Juan; Jia, Chang-Chun; Zhang, Li-Min; Chen, Jiao-Jiao; Chen, Zhang-Jin

    2013-10-01

    Within the framework of the first-order Born approximation, the triple differential cross sections (TDCSs) for simultaneous ionization and excitation of helium are calculated. The wave function of the ejected electron is chosen to be orthogonal or non-orthogonal to the wave function of the bound electron before ionization. It is found that the orthogonality has a strong effect on the TDCS, especially when plane waves and Coulomb waves are used to describe the projectile and the ejected electron.

  5. Numerical Investigation of the New Observation-Based Wind-Wave Source Function

    Microsoft Academic Search

    Alexander Babanin; Kakha Tsagareli; Ian Young; David Walker

    2010-01-01

    Numerical simulations of the wind-wave spectrum evolution are conducted by means of new observation-based wind-input and wave-dissipation functions obtained in the Lake George field experiment. This experiment allowed simultaneous measurements of the source functions in a broad range of conditions, including extreme wind-wave circumstances. Results of the experiment revealed new physical mechanisms in the processes of spectral input\\/dissipation of wave

  6. Semi-empirical dissipation source functions for ocean waves: Part I, definition, calibration and validation

    E-print Network

    Ardhuin, Fabrice; Babanin, Alexander; Filipot, Jean-François; Magne, Rudy; Roland, Aron; Van Der Westhuysen, Andre; Queffeulou, Pierre; Lefevre, Jean-Michel; Aouf, Lotfi; Collard, Fabrice

    2009-01-01

    New parameterizations for the spectra dissipation of wind-generated waves are proposed. The rates of dissipation have no predetermined spectral shapes and are functions of the wave spectrum and wind speed and direction, in a way consistent with observation of wave breaking and swell dissipation properties. Namely, the swell dissipation is nonlinear and proportional to the swell steepness, and dissipation due to wave breaking is non-zero only when a non-dimensional spectrum exceeds the threshold at which waves are observed to start breaking. An additional source of short wave dissipation due to long wave breaking is introduced to represent the dissipation of short waves due to longer breaking waves. Several degrees of freedom are introduced in the wave breaking and the wind-wave generation term of Janssen (J. Phys. Oceanogr. 1991). These parameterizations are combined and calibrated with the Discrete Interaction Approximation of Hasselmann et al. (J. Phys. Oceangr. 1985) for the nonlinear interactions. Paramet...

  7. A Search for Seismic Waves from the Impact of the SL/9 R Fragment

    NASA Astrophysics Data System (ADS)

    Walter, Charles M.; Marley, Mark S.; Hunten, Donald M.; Sprague, Ann L.; Wells, William K.; Dayal, Aditya; Hoffmann, William F.; Sykes, Mark V.; Deutsch, Lynne K.; Fazio, Giovanni G.; Hora, Joseph L.

    1996-06-01

    Jupiter was observed in the aftermath of its impact with fragment R of Comet Shoemaker-Levy/9 to search for seismic waves excited by the collision. Observations were made in the 7.8 ?m methane emission band with the MIRAC2 camera at the IRTF in an attempt to detect the local perturbation to the equilibrium stratospheric temperature profile induced by the wave. Detection of a jovian seismic wave would provide the tightest constraint to date on interior models of Jupiter. Seismic waves were detected in neither direct images of the planet nor in a composite time-distance diagram which utilizes all of the available imagery. This non-detection allows us to place an upper limit on the energy of the fragment R impact of 1 × 1028erg, assuming a seismic wave excitation efficiency of 15%.

  8. Impact of lightning strikes on hospital functions.

    PubMed

    Mortelmans, Luc J M; Van Springel, Gert L J; Van Boxstael, Sam; Herrijgers, Jan; Hoflacks, Stefaan

    2009-01-01

    Two regional hospitals were struck by lightning during a one-month period. The first hospital, which had 236 beds, suffered a direct strike to the building. This resulted in a direct spread of the power peak and temporary failure of the standard power supply. The principle problems, after restoring standard power supply, were with the fire alarm system and peripheral network connections in the digital radiology systems. No direct impact on the hardware could be found. Restarting the servers resolved all problems. The second hospital, which had 436 beds, had a lightning strike on the premises and mainly experienced problems due to induction. All affected installations had a cable connection from outside in one way or another. The power supplies never were endangered. The main problem was the failure of different communication systems (telephone, radio, intercom, fire alarm system). Also, the electronic entrance control went out. During the days after the lightening strike, multiple software problems became apparent, as well as failures of the network connections controlling the technical support systems. There are very few ways to prepare for induction problems. The use of fiber-optic networks can limit damage. To the knowledge of the authors, these are the first cases of lightning striking hospitals in medical literature. PMID:20066646

  9. Orientation Dynamics of Asymmetric Rotors Using Random Phase Wave Functions

    E-print Network

    Kallush, Shimshon

    2015-01-01

    Intense terahertz-frequency pulses induce coherent rotational dynamics and orientation of polar molecular ensembles. Exact numerical methods for rotational dynamics are computationally not feasible for the vast majority of molecular rotors - the asymmetric top molecules at ambient temperatures. We exemplify the use of Random Phase Wave Functions (RPWF) by calculating the terahertz-induced rotational dynamics of sulfur dioxide (SO2) at ambient temperatures and high field strengths and show that the RPWF method gains efficiency with the increase in temperature and in the THz-field strengths. The presented method provides wide-ranging computational access to rotational dynamical responses of molecules at experimental conditions which are far beyond the reach of exact numerical methods.

  10. Orientation Dynamics of Asymmetric Rotors Using Random Phase Wave Functions

    E-print Network

    Shimshon Kallush; Sharly Fleischer

    2015-04-28

    Intense terahertz-frequency pulses induce coherent rotational dynamics and orientation of polar molecular ensembles. Exact numerical methods for rotational dynamics are computationally not feasible for the vast majority of molecular rotors - the asymmetric top molecules at ambient temperatures. We exemplify the use of Random Phase Wave Functions (RPWF) by calculating the terahertz-induced rotational dynamics of sulfur dioxide (SO2) at ambient temperatures and high field strengths and show that the RPWF method gains efficiency with the increase in temperature and in the THz-field strengths. The presented method provides wide-ranging computational access to rotational dynamical responses of molecules at experimental conditions which are far beyond the reach of exact numerical methods.

  11. Finite temperature wave-function renormalization, a comparative analysis

    SciTech Connect

    Chapman, I.A.

    1996-12-31

    We compare two competing theories regarding finite temperature wave-function corrections for the process H {r_arrow} e{sup +}e{sup {minus}} and for n + {nu} {r_arrow} p + e{sup {minus}} and related processes of interest for primordial nucleosynthesis. Although the two methods are distinct (as shown in H {r_arrow} e{sup +}e{sup {minus}}) they yield the same finite temperature correction for all n {r_arrow} p and p {r_arrow} n processes. Both methods yield an increase in the He/H ratio of 0.01% due to finite temperature renormalization rather than a decrease of 0.16% as previously predicted. 6 refs., 3 figs.

  12. Topological wave functions and the 4D-5D lift

    E-print Network

    Gao, Peng

    2008-01-01

    We revisit the holomorphic anomaly equations satisfied by the topological string amplitude from the perspective of the 4D-5D lift, in the context of ``magic'' N=2 supergravity theories. In particular, we interpret the Gopakumar-Vafa relation between 5D black hole degeneracies and the topological string amplitude as the result of a canonical transformation from 4D to 5D charges. Moreover we use the known Bekenstein-Hawking entropy of 5D black holes to constrain the asymptotic behavior of the topological wave function at finite topological coupling but large K\\"ahler classes. In the process, some subtleties in the relation between 5D black hole degeneracies and the topological string amplitude are uncovered, but not resolved. Finally we extend these considerations to the putative one-parameter generalization of the topological string amplitude, and identify the canonical transformation as a Weyl reflection inside the 3D duality group.

  13. Topological wave functions and the 4D-5D lift

    NASA Astrophysics Data System (ADS)

    Gao, Peng; Pioline, Boris

    2008-07-01

    We revisit the holomorphic anomaly equations satisfied by the topological string amplitude from the perspective of the 4D-5D lift, in the context of ``magic'' Script N = 2 supergravity theories. In particular, we interpret the Gopakumar-Vafa relation between 5D black hole degeneracies and the topological string amplitude as the result of a canonical transformation from 4D to 5D charges. Moreover we use the known Bekenstein-Hawking entropy of 5D black holes to constrain the asymptotic behavior of the topological wave function at finite topological coupling but large Kähler classes. In the process, some subtleties in the relation between 5D black hole degeneracies and the topological string amplitude are uncovered, but not resolved. Finally we extend these considerations to the putative one-parameter generalization of the topological string amplitude, and identify the canonical transformation as a Weyl reflection inside the 3D duality group.

  14. Topological wave functions and the 4D-5D lift

    E-print Network

    Peng Gao; Boris Pioline

    2008-07-14

    We revisit the holomorphic anomaly equations satisfied by the topological string amplitude from the perspective of the 4D-5D lift, in the context of ''magic'' N=2 supergravity theories. In particular, we interpret the Gopakumar-Vafa relation between 5D black hole degeneracies and the topological string amplitude as the result of a canonical transformation from 4D to 5D charges. Moreover we use the known Bekenstein-Hawking entropy of 5D black holes to constrain the asymptotic behavior of the topological wave function at finite topological coupling but large K\\"ahler classes. In the process, some subtleties in the relation between 5D black hole degeneracies and the topological string amplitude are uncovered, but not resolved. Finally we extend these considerations to the putative one-parameter generalization of the topological string amplitude, and identify the canonical transformation as a Weyl reflection inside the 3D duality group.

  15. Orientation dynamics of asymmetric rotors using random phase wave functions

    NASA Astrophysics Data System (ADS)

    Kallush, Shimshon; Fleischer, Sharly

    2015-06-01

    Intense terahertz-frequency pulses induce coherent rotational dynamics and orientation of polar molecular ensembles. Exact numerical methods for rotational dynamics at room temperature are computationally not feasible for the vast majority of molecular rotors: the asymmetric top molecules at ambient temperatures. We exemplify the use of random phase wave functions (RPWFs) by calculating the terahertz-induced rotational dynamics of sulfur dioxide at ambient temperatures and high-field strengths and show that the RPWF method gains efficiency with the increase in temperature and in the terahertz-field strengths. The present method provides wide-ranging computational access to rotational dynamical responses of molecules at experimental conditions that are far beyond the reach of exact numerical methods.

  16. Wave functions of hot excitons in semiconductors with degenerate bands

    SciTech Connect

    Efanov, A. V. [Russian Academy of Sciences, Institute of Semiconductor Physics, Siberian Branch (Russian Federation)], E-mail: efanov@isp.nsc.ru

    2008-06-15

    Hot excitons in direct-gap cubic semiconductors with a degenerate valence band are considered. Corrections to the model of independent excitonic branches in terms of the small parameter {Dirac_h}/Ka{sub B}, where K is the exciton momentum and a{sub B} is the Bohr radius, are determined. The corrections take into account the internal motion of particles in the exciton. It is shown that the internal motion mixes the states of light and heavy holes in the exciton wave function. As a result, the processes of forward scattering of excitons with transitions between different excitonic branches become allowed. The consideration is concerned with the region of kinetic energies no higher than the spin-orbit splitting in the valence band. The dispersion relation for holes is described in the spherical Kohn-Luttinger model (the 4 x 4 matrix)

  17. Glueball Wave Functions in U(1) Lattice Gauge Theory

    E-print Network

    Mushtaq Loan; Yi Ying

    2006-06-26

    Standard Monte Carlo simulations have been performed for 3-dimensional U(1) lattice gauge model on improved lattices to measure the wavefunction and size of the scalar and the tensor glueballs. Our results show the radii of ~ 0.60 and ~ 1.12 in the units of string tension, or ~0.28 and ~0.52 fm, for the scalar and tensor glueballs, respectively. At finite temperature we see clear evidence of the deconfined phase, and the transition appears to be similar to that of the two-dimensional XY model as expected from universality arguments. Preliminary results show no significant changes in the glueball wave functions and the masses in the deconfined phase.

  18. Wave-function-based correlated ab initio calculations on crystalline solids Alok Shukla*

    E-print Network

    Birkenheuer, Uwe

    of Wannier functions. Electron correlation effects are evaluated by considering virtual excitations fromWave-function-based correlated ab initio calculations on crystalline solids Alok Shukla* Department¨r Theoretische Chemie, Universita¨t Stuttgart, D-70550 Stuttgart, Germany Received 2 March 1999 We present a wave-function

  19. Impact of wind waves on the air-sea fluxes: A coupled model

    NASA Astrophysics Data System (ADS)

    Kudryavtsev, V.; Chapron, B.; Makin, V.

    2014-02-01

    A revised wind-over-wave-coupling model is developed to provide a consistent description of the sea surface drag and heat/moister transfer coefficients, and associated wind velocity and temperature profiles. The spectral distribution of short wind waves in the decimeter to a few millimeters range of wavelengths is introduced based on the wave action balance equation constrained using the Yurovskaya et al. (2013) optical field wave measurements. The model is capable to reproduce fundamental statistical properties of the sea surface, such as the mean square slope and the spectral distribution of breaking crests length. The surface stress accounts for the effect of airflow separation due to wave breaking, which enables a better fit of simulated form drag to observations. The wave breaking controls the overall energy losses for the gravity waves, but also the generation of shorter waves including the parasitic capillaries, thus enhancing the form drag. Breaking wave contribution to the form drag increases rapidly at winds above 15 m/s where it exceeds the nonbreaking wave contribution. The overall impact of wind waves (breaking and nonbreaking) leads to a sheltering of the near-surface layer where the turbulent mixing is suppressed. Accordingly, the air temperature gradient in this sheltered layer increases to maintain the heat flux constant. The resulting deformation of the air temperature profile tends to lower the roughness scale for temperature compared to its value over the smooth surface.

  20. Impact of ozone depletion on immune function

    SciTech Connect

    Jeevan, A.; Kripke, M.L. (Univ. of Texas, Houston, TX (United States). Dept. of Immunology)

    1993-06-01

    Depletion of stratospheric ozone is expected to lead to an increase in the amount of UV-B radiation present in sunlight. In addition to its well known ability to cause skin cancer, UV-B radiation has been shown to alter the immune system. The immune system is the body's primary defense mechanism against infectious diseases and protects against the development of certain types of cancer. Any impairment of immune function may jeopardize health by increasing susceptibility to infectious diseases, increasing the severity of infections, or delaying recovery for infections. In addition, impaired immune function can increase the incidence of certain cancers, particularly cancers of the skin. Research carried out with laboratory animals over the past 15 years has demonstrated that exposure of the skin to UV-B radiation can suppress certain types of immune responses. These include rejection of UV-induced skin cancers and melanomas, contact allergy reactions to chemicals, delayed-type hypersensitivity responses to microbial and other antigens, and phagocytosis and elimination of certain bacteria from lymphoid tissues. Recent studies with mycobacterial infection of mice demonstrated that exposure to UV-B radiation decreased the delayed hypersensitivity response to mycobacterial antigens and increased the severity of infection. In humans, UV-B radiation has also been shown to impair the contact allergy response. These studies demonstrate that UV radiation can decrease immune responses in humans and laboratory and raise the possibility that increased exposure to UV-B radiation could adversely affect human health by increasing the incidence or severity of certain infectious diseases.

  1. Variational Approach to Yang--Mills Theory with non-Gaussian Wave Functionals

    E-print Network

    Davide R. Campagnari; Hugo Reinhardt

    2010-11-22

    A general method for treating non-Gaussian wave functionals in quantum field theory is presented and applied to the Hamiltonian approach to Yang-Mills theory in Coulomb gauge in order to include a three-gluon kernel in the exponential of the vacuum wave functional. The three-gluon vertex is calculated using the propagators found in the variational approach with a Gaussian trial wave functional as input.

  2. Wave propagation in graphite/epoxy laminates due to impact

    NASA Technical Reports Server (NTRS)

    Tan, T. M.; Sun, C. T.

    1982-01-01

    The low velocity impact response of graphite-epoxy laminates is investigated theoretically and experimentally. A nine-node isoparametric finite element in conjunction with an empirical contact law was used for the theoretical investigation. Flat laminates subjected to pendulum impact were used for the experimental investigation. Theoretical results are in good agreement with strain gage experimental data. The collective results of the investigation indicate that the theoretical procedure describes the impact response of the laminate up to about 150 in/sec. impact velocity.

  3. Using soil functional indices to assess wildfire impact

    NASA Astrophysics Data System (ADS)

    López-Poma, Rosario; Mayor, Ángeles G.; Bautista, Susana

    2014-05-01

    Disturbance impact on ecosystem are often based on functional indicators, which provide integrated and yet simple and affordable measures of key ecosystem functions. In this work, we studied the amount of change (resistance) and the recovery (resilience) of soil functions after fire as a function of vegetation type for a variety of Mediterranean shrublands. We used the Landscape Functional Analysis methodology to assess soil stability, water infiltration, and nutrient cycling functions for different types of vegetation patches and for bare-soil interpatches in repeatedly burned shrubland communities two weeks before, and two and nine months after experimental fires. We assessed the impact of fire on soil functions using resistance and resilience indices. The resistance and resilience of soil surface functions to fire was mediated by vegetation traits associated to the fuel structure and the post-fire regenerative strategy of the species. Resistance was higher in vegetation patches that accumulated low contents of fine dead fuel, whereas resilience was higher in patches of resprouter species. The variation in resistance and resilience of soil functions to fire in Mediterranean shrublands depends greatly on variation in fire-related plant structural and functional traits. Although originally designed for the assessment of dryland ecosystems LFA has proved to have great potential for the assessment of the soil functional status of recently burned areas.

  4. Impact ionization in GaAs: A screened exchange density-functional approach

    SciTech Connect

    Picozzi, S.; Asahi, R.; Geller, C. B.; Continenza, A.; Freeman, A. J.

    2001-08-13

    Results are presented of a fully ab initio calculation of impact ionization rates in GaAs within the density functional theory framework, using a screened-exchange formalism and the highly precise all-electron full-potential linearized augmented plane wave method. The calculated impact ionization rates show a marked orientation dependence in k space, indicating the strong restrictions imposed by the conservation of energy and momentum. This anisotropy diminishes as the impacting electron energy increases. A Keldysh type fit performed on the energy-dependent rate shows a rather soft edge and a threshold energy greater than the direct band gap. The consistency with available Monte Carlo and empirical pseudopotential calculations shows the reliability of our approach and paves the way to ab initio calculations of pair production rates in new and more complex materials.

  5. Baryon wave functions and cross sections for photon annihilation to baryon pairs

    NASA Astrophysics Data System (ADS)

    Farrar, G. R.; Zhang, H.; Ogloblin, A. A.; Zhitnitsky, I. R.

    1989-01-01

    The first few moments of the wave functions for ?'s and ? are evaluated by QCD sum rules. Model wave functions are constructed based on these moments. Perturbative QCD predictions of cross sections for ?? ? ? ++overline? ++ and ?? ? ? overline? are obtained by integrating the quark scattering amplitudes over these wave functions. The ratio of ?? ? ? ++overline? ++ and ?? ? p p¯ cross sections is much lower than would be naively expected. Predictions for ?? ? B 8overlineB 8 are also given for the full baryon octet with QCD sum-rule wave functions.

  6. Pion and photon light-cone wave functions from the instanton vacuum

    NASA Astrophysics Data System (ADS)

    Petrov, V. Yu.; Polyakov, M. V.; Ruskov, R.; Weiss, C.; Goeke, K.

    1999-06-01

    The leading-twist wave functions of the pion and the photon at a low normalization point are calculated in the effective low-energy theory derived from the instanton vacuum. The pion wave function is found to be close to the asymptotic one, consistent with the recent CLEO measurements. The photon wave function is nonzero at the end points. This different behavior is a consequence of the momentum dependence of the dynamical quark mass suggested by the instanton vacuum. We comment on the relation of meson wave functions and off-forward parton distributions in this model.

  7. Multipole wave functions for photoelectrons in crystals. III. The role of singular points in the band structure and the tails of the Wannier functions

    Microsoft Academic Search

    G. Strinati

    1978-01-01

    Properties of multipole wave functions and of Wannier functions are studied jointly, because both are generated by unitary transformations of Bloch waves and because their symmetry and localization depend on the analytic behavior and phase normalization of Bloch waves. Fourier theory relates the amplitude and convergence of the tails of Wannier functions to the singularities of Bloch waves in k-->

  8. Impact of Locally Suppressed Wave sources on helioseismic travel times

    E-print Network

    S. M. Hanasoge; S. Couvidat; S. P. Rajaguru; A. C. Birch

    2008-03-13

    Wave travel-time shifts in the vicinity of sunspots are typically interpreted as arising predominantly from magnetic fields, flows, and local changes in sound speed. We show here that the suppression of granulation related wave sources in a sunspot can also contribute significantly to these travel-time shifts, and in some cases, an asymmetry between in and outgoing wave travel times. The tight connection between the physical interpretation of travel times and source-distribution homogeneity is confirmed. Statistically significant travel-time shifts are recovered upon numerically simulating wave propagation in the presence of a localized decrease in source strength. We also demonstrate that these time shifts are relatively sensitive to the modal damping rates; thus we are only able to place bounds on the magnitude of this effect. We see a systematic reduction of 10-15 seconds in $p$-mode mean travel times at short distances ($\\sim 6.2$ Mm) that could be misinterpreted as arising from a shallow (thickness of 1.5 Mm) increase ($\\sim$ 4%) in the sound speed. At larger travel distances ($\\sim 24$ Mm) a 6-13 s difference between the ingoing and outgoing wave travel times is observed; this could mistakenly be interpreted as being caused by flows.

  9. Semiempirical Dissipation Source Functions for Ocean Waves. Part I: Definition, Calibration, and Validation

    Microsoft Academic Search

    Fabrice Ardhuin; Erick Rogers; Alexander V. Babanin; Jean-François Filipot; Rudy Magne; Aaron Roland; Andre van der Westhuysen; Pierre Queffeulou; Jean-Michel Lefevre; Lotfi Aouf; Fabrice Collard

    2010-01-01

    New parameterizations for the spectra dissipation of wind-generated waves are proposed. The rates of dissipation have no predetermined spectral shapes and are functions of the wave spectrum and wind speed and direction, in a way consistent with observation of wave breaking and swell dissipation properties. Namely, the swell dissipation is nonlinear and proportional to the swell steepness, and dissipation due

  10. Scattering of Thermal Waves and Unsteady Effective Thermal Conductivity of Particular Composites with Functionally Graded Interface

    Microsoft Academic Search

    Xue-Qian Fang; Jin-Xi Liu; Ting Zhang; Xiao-Hua Wang

    2009-01-01

    In this study, thermal wave method is applied to investigate the unsteady effective thermal conductivity of particular composites with a functionally graded interface, and the analytical solution of the problem is obtained. The Fourier heat conduction law is applied to analyze the propagation of thermal waves in the particular composite. The scattering and refraction of thermal waves by a spherical

  11. Quantization causes waves:Smooth finitely computable functions are affine

    E-print Network

    Vladimir Anashin

    2015-02-06

    Given an automaton (a letter-to-letter transducer, a dynamical 1-Lipschitz system on the space $\\mathbb Z_p$ of $p$-adic integers) $\\mathfrak A$ whose input and output alphabets are $\\mathbb F_p=\\{0,1,\\ldots,p-1\\}$, one visualizes word transformations performed by $\\mathfrak A$ by a point set $\\mathbf P(\\mathfrak A)$ in real plane $\\mathbb R^2$. For a finite-state automaton $\\mathfrak A$, it is shown that once some points of $\\mathbf P(\\mathfrak A)$ constitute a smooth (of a class $C^2$) curve in $\\mathbb R^2$, the curve is a segment of a straight line with a rational slope; and there are only finitely many straight lines whose segments are in $\\mathbf{P}(\\mathfrak A)$. Moreover, when identifying $\\mathbf P(\\mathfrak A)$ with a subset of a 2-dimensional torus $\\mathbb T^2\\subset\\mathbb R^3$ (under a natural mapping of the real unit square $[0,1]^2$ onto $\\mathbb T^2$) the smooth curves from $\\mathbf P(\\mathfrak A)$ constitute a collection of torus windings. In cylindrical coordinates either of the windings can be ascribed to a complex-valued function $\\psi(x)=e^{i(Ax-2\\pi B(t))}$ $(x\\in\\mathbb R)$ for suitable rational $A,B(t)$. Since $\\psi(x)$ is a standard expression for a matter wave in quantum theory (where $B(t)=tB(t_0)$), and since transducers can be regarded as a mathematical formalization for causal discrete systems, the paper might serve as a mathematical reasoning why wave phenomena are inherent in quantum systems: This is because of causality principle and the discreteness of matter.

  12. Impact of complex blast waves on the human head: a computational study.

    PubMed

    Tan, Long Bin; Chew, Fatt Siong; Tse, Kwong Ming; Chye Tan, Vincent Beng; Lee, Heow Pueh

    2014-12-01

    Head injuries due to complex blasts are not well examined because of limited published articles on the subject. Previous studies have analyzed head injuries due to impact from a single planar blast wave. Complex or concomitant blasts refer to impacts usually caused by more than a single blast source, whereby the blast waves may impact the head simultaneously or consecutively, depending on the locations and distances of the blast sources from the subject, their blast intensities, the sequence of detonations, as well as the effect of blast wave reflections from rigid walls. It is expected that such scenarios will result in more serious head injuries as compared to impact from a single blast wave due to the larger effective duration of the blast. In this paper, the utilization of a head-helmet model for blast impact analyses in Abaqus(TM) (Dassault Systemes, Singapore) is demonstrated. The model is validated against studies published in the literature. Results show that the skull is capable of transmitting the blast impact to cause high intracranial pressures (ICPs). In addition, the pressure wave from a frontal blast may enter through the sides of the helmet and wrap around the head to result in a second impact at the rear. This study recommended better protection at the sides and rear of the helmet through the use of foam pads so as to reduce wave entry into the helmet. The consecutive frontal blasts scenario resulted in higher ICPs compared with impact from a single frontal blast. This implied that blast impingement from an immediate subsequent pressure wave would increase severity of brain injury. For the unhelmeted head case, a peak ICP of 330?kPa is registered at the parietal lobe which exceeds the 235?kPa threshold for serious head injuries. The concurrent front and side blasts scenario yielded lower ICPs and skull stresses than the consecutive frontal blasts case. It is also revealed that the additional side blast would only significantly affect ICPs at the temporal and parietal lobes when compared with results from the single frontal blast case. By analyzing the pressure wave flow surrounding the head and correlating them with the consequential evolution of ICP and skull stress, the paper provides insights into the interaction mechanics between the concomitant blast waves and the biological head model. PMID:25132676

  13. P-wave Receiver Functions reveal the Bohemian Massif crust

    NASA Astrophysics Data System (ADS)

    Kampfova Exnerova, Hana; Plomerova, Jaroslava; Vecsey, Ludek

    2015-04-01

    In this study we present initial results of P-wave Receiver Functions (RF) calculated from broad-band waveforms of teleseismic events recorded by temporary and permanent stations in the Bohemian Massif (BM, Central Europe). Temporary arrays BOHEMA I (2001-2003), BOHEMA II (2004-2005) and BOHEMA III (2005-2006) operated during passive seismic experiments oriented towards studying velocity structure of the lithosphere and the upper mantle. Receiver Functions show relative response of the Earth structure under a seismic station and nowadays represent frequently-used method to retrieve structure of the crust, whose knowledge is needed in various studies of the upper mantle. The recorded waveforms are composites of direct P and P-to-S converted waves that reverberate in the structure beneath the receiver (Ammon, 1997). The RFs are sensitive to seismic velocity contrast and are thus suited to identifying velocity discontinuities in the crust, including the Mohorovi?i? discontinuity (Moho). Relative travel-time delays of the converted phases detected in the RFs are transformed into estimates of discontinuity depths assuming external information on the vp/vs and P velocity. To evaluate RFs we use the Multiple-taper spectral correlation (MTC) method (Park and Levin, 2000) and process signals from teleseismic events at epicentral distances of 30 - 100° with magnitude Mw > 5.5. Recordings are filtered with Butterworth band-pass filter of 2 - 8 s. To select automatically signals which are strong enough, we calculate signal-to-noise ratios (SNR) in two steps. In the first step we calculate SNR for signals from intervals (-1s, 3s)/(-10s, -2s), where P-arrival time represent time zero. In the second step we broaden the intervals and calculate SNR for (-1s, 9s)/(-60s, -2s). We also employ forward modelling of the RFs using Interactive Receiver Functions Forward Modeller (IRFFM) (Tkal?i? et al., 2010) to produce, in the first step, one-dimensional velocity models under individual seismic station. Stacked traces of the RFs show strong conversions with positive polarity (indicating a velocity increase across the discontinuity) between 3.3 and 4.5 s after the P-wave arrival at almost all stations. We relate these pulses to conversions at the Moho discontinuity. Assuming a constant crustal vp/vs ratio (1.73) and average crustal velocity vp=6.3 km/s for all stations, analogically to Geissler et al (2012), we multiply the evaluated Ps delay times by factor of 8.3 km/s and estimate the Moho beneath the Bohemian Massif at depths between 27 and 37 km. The crust is thinnest in the western part of the BM, beneath the SW end of the Eger Rift. The Moldanubian part of the BM exhibits the thickest crust. At most of the stations we also see one or two intra-crustal conversions, sometimes stronger than that related to the Moho. Several stations exhibit significant variations of the RF with back-azimuth. The aim of this study is to update existing three dimensional P-velocity crustal model of the Bohemian Massif (Karousová et al., 2012) compiled from control-source seismic results.

  14. Impact of wave action on the structure of material on the beach in Calypsobyen (Spitsbergen)

    NASA Astrophysics Data System (ADS)

    M?drek, Karolina; Herman, Agnieszka; Moskalik, Mateusz; Rodzik, Jan; Zagórski, Piotr

    2015-04-01

    The research was conducted during the XXVI Polar Expedition of Maria Curie-Sklodowska University in Lublin on Spitsbergen. It involved recording water wave action in the Bellsund Strait, and taking daily photographs of the beach on its shore in Calypsobyen. The base of polar expeditions of UMCS, Calypsobyen, is located on the coast of Calypsostranda, developed by raised marine terraces. Weakly resistant Tertiary sandstones occur in the substrate, covered with glacigenic sediments and marine gravels. No skerries are encountered along this section of the accumulation coast. The shore is dominated by gravel deposits. The bottom slopes gently. The recording of wave action was performed from 8 July to 27 August 2014 by means of a pressure based MIDAS WTR Wave and Tide Recorder set at a depth of 10 m at a distance of about 1 km from the shore. The obtained data provided the basis for the calculation of the significant wave height, and the corresponding mean wave period . These parameters reflect wave energy and wave level, having a considerable impact on the dynamics of coastal processes and the type and grain size of sediments accumulated on the beach. Material consisting of medium gravel and seaweed appeared on the beach at high values of significant wave height and when the corresponding mean wave period showed average values. The contribution of fine, gravel-sandy material grew with an increase in mean period and a decrease in significant wave height. At maximum values of mean period and low values of significant wave height, the beach was dominated by well-sorted fine-grained gravel. The lowest mean periods resulted in the least degree of sorting of the sediment (from very coarse sand to medium gravel). The analysis of data from the wave and tide recorder set and their comparison with photographs of the beach suggest that wave action, and particularly wave energy manifested in significant wave height, has a considerable impact on the type and grain size of material occurring on the shore of the fjord. The mean period is mainly responsible for sorting out the sediment, and the size of gravels is associated with significant wave height. Project of National Science Centre no. DEC-2013/09/B/ST10/04141

  15. Covariant nucleon wave function with S, D, and P-state components

    E-print Network

    Franz Gross; G. Ramalho; M. T. Pena

    2012-01-30

    Expressions for the nucleon wave functions in the covariant spectator theory (CST) are derived. The nucleon is described as a system with a off-mass-shell constituent quark, free to interact with an external probe, and two spectator constituent quarks on their mass shell. Integrating over the internal momentum of the on-mass-shell quark pair allows us to derive an effective nucleon wave function that can be written only in terms of the quark and diquark (quark-pair) variables. The derived nucleon wave function includes contributions from S, P and D-waves.

  16. Covariant nucleon wave function with S, D, and P-state components

    SciTech Connect

    Franz Gross, G. Ramalho, M. T. Pena

    2012-05-01

    Expressions for the nucleon wave functions in the covariant spectator theory (CST) are derived. The nucleon is described as a system with a off-mass-shell constituent quark, free to interact with an external probe, and two spectator constituent quarks on their mass shell. Integrating over the internal momentum of the on-mass-shell quark pair allows us to derive an effective nucleon wave function that can be written only in terms of the quark and diquark (quark-pair) variables. The derived nucleon wave function includes contributions from S, P and D-waves.

  17. function twomass %for analysing impact of two-mass model

    E-print Network

    Talbot, James P.

    ,h]=param k1=10e6; %contact pad stiffness k2=5e6; % %platform stiffness m1=2000; %drop weight mass m2function twomass %2-mass %-------------------- %for analysing impact of two-mass model %Hugh Hunt Cambridge University Engineering Department %www.hughhunt.com % % === % === m1 being dropped % % % + % + k1

  18. A fully nonlinear wave model to account for breaking wave impact loads on offshore wind turbines

    Microsoft Academic Search

    Enzo Marino; Claudio Borri; Udo Peil

    2011-01-01

    This paper presents a numerical model capable of simulating offshore wind turbines exposed to extreme loading conditions. External condition-based extreme responses are reproduced by coupling a fully nonlinear wave kinematic solver with a hydro-aero-elastic simulator. The transient nonlinear free surface problem of water waves is formulated assuming the potential theory and a higher-order boundary element method (HOBEM) is used to

  19. Assessment of the Impact of the 2003 and 2006 Heat Waves on Cattle Mortality in France

    PubMed Central

    Morignat, Eric; Perrin, Jean-Baptiste; Gay, Emilie; Vinard, Jean-Luc; Calavas, Didier; Hénaux, Viviane

    2014-01-01

    Objectives While several studies have highlighted and quantified human mortality during the major heat waves that struck Western Europe in 2003 and 2006, the impact on farm animals has been overlooked. The aim of this study was to assess the effect of these two events on cattle mortality in France, one of the most severely impacted countries. Methods Poisson regressions were used to model the national baseline for cattle mortality between 2004 and 2005 and predict the weekly number of expected deaths in 2003 and 2006 for the whole cattle population and by subpopulation based on age and type of production. Observed and estimated values were compared to identify and quantify excess mortality. The same approach was used at a departmental scale (a French department being an administrative and territorial division) to assess the spatio-temporal evolution of the mortality pattern. Results Overall, the models estimated relative excess mortality of 24% [95% confidence interval: 22–25%] for the two-week heat wave of 2003, and 12% [11–14%] for the three-week heat wave of 2006. In 2003, most cattle subpopulations were impacted during the heat wave and some in the following weeks too. In 2006, cattle subpopulations were impacted for a limited time only, with no excess mortality at the beginning or after the heat wave. No marked differences in cattle mortality were found among the different subpopulations by age and type of production. The implications of these results for risk prevention are discussed. PMID:24667835

  20. Hadronic spectra and light-front wave functions in holographic QCD.

    PubMed

    Brodsky, Stanley J; de Téramond, Guy F

    2006-05-26

    We show how the string amplitude phi(z) defined on the fifth dimension in AdS5 space can be precisely mapped to the light-front wave functions of hadrons in physical space-time. We find an exact correspondence between the holographic variable z and an impact variable zeta, which represents the measure of transverse separation of the constituents within the hadrons. In addition, we derive effective four dimensional Schrödinger equations for the bound states of massless quarks and gluons which exactly reproduce the anti-de Sitter conformal field theory results and give a realistic description of the light-quark meson and baryon spectrum as well as the form factors for space-like Q2. Only one parameter which sets the mass scale, lambda(QCD), is introduced. PMID:16803163

  1. Hadronic Spectra and Light-Front Wave Functions in Holographic QCD

    SciTech Connect

    Brodsky, Stanley J. [Stanford Linear Accelerator Center, Stanford University, Stanford, California 94309 (United States); Teramond, Guy F. de [Universidad de Costa Rica, San Jose (Costa Rica)

    2006-05-26

    We show how the string amplitude {phi}(z) defined on the fifth dimension in AdS{sub 5} space can be precisely mapped to the light-front wave functions of hadrons in physical space-time. We find an exact correspondence between the holographic variable z and an impact variable {zeta}, which represents the measure of transverse separation of the constituents within the hadrons. In addition, we derive effective four dimensional Schroedinger equations for the bound states of massless quarks and gluons which exactly reproduce the anti-de Sitter conformal field theory results and give a realistic description of the light-quark meson and baryon spectrum as well as the form factors for spacelike Q{sup 2}. Only one parameter which sets the mass scale, {lambda}{sub QCD}, is introduced.

  2. Hadronic Spectra and Light-Front Wave Functions in Holographic QCD

    NASA Astrophysics Data System (ADS)

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

    2006-05-01

    We show how the string amplitude ?(z) defined on the fifth dimension in AdS5 space can be precisely mapped to the light-front wave functions of hadrons in physical space-time. We find an exact correspondence between the holographic variable z and an impact variable ?, which represents the measure of transverse separation of the constituents within the hadrons. In addition, we derive effective four dimensional Schrödinger equations for the bound states of massless quarks and gluons which exactly reproduce the anti de Sitter conformal field theory results and give a realistic description of the light-quark meson and baryon spectrum as well as the form factors for spacelike Q2. Only one parameter which sets the mass scale, ?QCD, is introduced.

  3. The Yang-Mills vacuum wave functional thirty-five years later

    E-print Network

    Olejnik, Stefan

    2015-01-01

    The first paper attempting direct calculation of the Yang-Mills vacuum wave functional was published by Greensite in 1979. I review some recent results of the determination of the vacuum wave functional in Monte Carlo simulations of SU(2) lattice gauge theory.

  4. The Influence of Superpositional Wave Function Oscillations on Shor's Quantum Algorithm

    E-print Network

    Gennady P. Berman; Gary D. Doolen; Vladimir I. Tsifrinovich

    1999-06-14

    We investigate the influence of superpositional wave function oscillations on the performance of Shor's quantum algorithm for factorization of integers. It is shown that the wave function oscillations can destroy the required quantum interference. This undesirable effect can be routinely eliminated using a resonant pulse implementation of quantum computation, but requires special analysis for non-resonant implementations.

  5. Quantum manifestations of classical stochasticity in the wave functions of quadrupole vibrations of nuclei

    SciTech Connect

    Bolotin, Yu.L.; Gonchar, V.Yu.; Tarasov, V.N. [National Research Center Khar`kov Physicotechnical Institute (Ukraine)

    1995-09-01

    Quantum manifestations of classical stochasticity in the structure of the stationary wave functions of highly excited states of the Hamiltonian of quadrupole vibrations are studied. Correlations between the structure of the wave functions and the type of classical motion are found in the regularity-chaos-regularity transition. 28 refs., 8 figs., 3 tabs.

  6. Quantum Monte Carlo: Direct calculation of corrections to trial wave functions and their energies

    E-print Network

    Anderson, James B.

    ARTICLES Quantum Monte Carlo: Direct calculation of corrections to trial wave functions, Pennsylvania 16802 Received 4 January 2000; accepted 10 March 2000 We report an improved Monte Carlo method Monte Carlo QMC method for the direct calculation of corrections to trial wave functions.1­3 We report

  7. Breaking Wave Impact on a Partially Submerged Rigid Cube in Deep Water

    NASA Astrophysics Data System (ADS)

    Ikeda, C. M.; Choquette, M.; Duncan, J. H.

    2011-11-01

    The impact of a plunging breaking wave on a partially submerged cube is studied experimentally. The experiments are performed in a wave tank that is 14.8 m long, 1.15 m wide and 2.2 m high with a water depth of 0.91 m. A single repeatable plunging breaker is generated from a dispersively focused wave packet (average frequency of 1.4 Hz) that is created with a programmable wave maker. The rigid (L = 30 . 5 cm) cube is centered in the width of the tank and mounted from above with one face oriented normal to the oncoming wave. The position of the center of the front face of the cube is varied from the breaker location (xb ~ 6 . 35 m) to xb + 0 . 05 m in the streamwise direction and from - 0 . 25 L to 0 . 25 L vertically relative to the mean water level. A high-speed digital camera is used to record both white-light and laser-induced fluorescence (LIF) movies of the free surface shape in front of the cube before and after the wave impact. When the wave hits the cube just as the plunging jet is formed, a high-velocity vertical jet is created and the trajectory and maximum height of the jet are strongly influenced by the vertical position of the cube. Supported by the Office of Naval Research, Contract Monitor R. D. Joslin.

  8. Stress Tensor for Quantized Random Field and Wave Function Collapse

    E-print Network

    Philip Pearle

    2008-08-13

    The continuous spontaneous localization (CSL) theory of dynamical wave function collapse is an experimentally testable alternative to non-relativistic quantum mechanics. In it, collapse occurs because particles interact with a classical random field. However, particles gain energy from this field, i.e., particle energy is not conserved. Recently, it has been shown how to construct a theory dubbed "completely quantized collapse" (CQC) which is predictively equivalent to CSL. In CQC, a quantized random field is introduced, and CSL's classical random field becomes its eigenvalue. In CQC, energy is conserved, which allows one to understand that energy is conserved in CSL, as the particle's energy gain is compensated by the random field's energy loss. Since the random field has energy, it should have gravitational consequences. For that, one needs to know the random field's energy density. In this paper, it is shown how to construct a symmetric, conserved, energy-momentum-stress-density tensor associated with the quantized random field, even though this field obeys no dynamical equation and has no Lagrangian. Then, three examples are given involving the random field's energy density. One considers interacting particles, the second treats a "cosmological" particle creation model, the third involves the gravity of the random field.

  9. Antisymmetric Wave Functions for Mixed Fermion States and Energy Convexity

    SciTech Connect

    Gonis, Antonios [ORNL; Zhang, Xiaoguang [ORNL; Nicholson, Don M [ORNL; Stocks, George Malcolm [ORNL

    2011-01-01

    We develop the formal basis for the study of independent collections of internally interacting many-particle systems, defined as systems associated with non-overlapping coordinate spaces. We show how ensembles or mixed states of independent many-Fermion systems in their ground states can be described by pure states and give rise to wave functions that are antisymmetric with respect to interchange of particle coordinates (and spin). This is achieved by defining an ensemble Hilbert space whose coordinate representation consists of the tensor sum, rather than product, of the coordinates of the systems in the ensemble. As a demonstration of the power of this new formalism, and under the assumptions of a positive interparticle interaction and a corresponding energy that is extensive in the number of particle pairs (pair extensive), we prove the convexity relation, $E_v[N-1]+E_v[N+1]\\ge 2E_v[N]$, where $E_v[N]$ denotes the total ground state energy of $N$ electrons under an external potential, $v({\\bf r})$.

  10. Experimental determination of wave function spread in Si inversion layers

    NASA Astrophysics Data System (ADS)

    Majumdar, Amlan

    2010-08-01

    We have experimentally determined the extent of wave function spread TQM in Si inversion layers on (100)-oriented surface in metal-oxide-semiconductor field-effect transistors (MOSFETs) using the back gate bias sensitivity of front gate threshold voltage of planar fully depleted silicon-on-insulator (SOI) MOSFETs. We show that the sum of TQM for large positive and negative F is an electrically determined value of the SOI thickness TSI. We find that the electric field dependence of TQM for electrons and holes is given by TQM˜F-0.4 and F-0.6, respectively, at high electric fields with TQM being larger for holes at a given F. Larger TQM for holes can be explained by the fact that holes have a smaller effective mass along the confinement direction than electrons in (100) Si. The field dependences of TQM are, however, not consistent with the results of variational calculations that assume single-subband occupancy and predict TQM˜F-1/3. The discrepancy likely indicates that the effects of multiple-subband occupation are significant at room temperature, especially for holes.

  11. Newton force from wave function collapse: speculation and test

    NASA Astrophysics Data System (ADS)

    Diósi, Lajos

    2014-04-01

    The Diosi-Penrose model of quantum-classical boundary postulates gravity-related spontaneous wave function collapse of massive degrees of freedom. The decoherence effects of the collapses are in principle detectable if not masked by the overwhelming environmental decoherence. But the DP (or any other, like GRW, CSL) spontaneous collapses are not detectable themselves, they are merely the redundant formalism of spontaneous decoherence. To let DP collapses become testable physics, recently we extended the DP model and proposed that DP collapses are responsible for the emergence of the Newton gravitational force between massive objects. We identified the collapse rate, possibly of the order of 1/ms, with the rate of emergence of the Newton force. A simple heuristic emergence (delay) time was added to the Newton law of gravity. This non-relativistic delay is in peaceful coexistence with Einstein's relativistic theory of gravitation, at least no experimental evidence has so far surfaced against it. We derive new predictions of such a 'lazy' Newton law that will enable decisive laboratory tests with available technologies. The simple equation of 'lazy' Newton law deserves theoretical and experimental studies in itself, independently of the underlying quantum foundational considerations.

  12. Epistemology of Wave Function Collapse in Quantum Physics

    E-print Network

    Charles Wesley Cowan; Roderich Tumulka

    2014-02-19

    Among several possibilities for what reality could be like in view of the empirical facts of quantum mechanics, one is provided by theories of spontaneous wave function collapse, the best known of which is the Ghirardi-Rimini-Weber (GRW) theory. We show mathematically that in GRW theory (and similar theories) there are limitations to knowledge, that is, inhabitants of a GRW universe cannot find out all the facts true about their universe. As a specific example, they cannot accurately measure the number of collapses that a given physical system undergoes during a given time interval; in fact, they cannot reliably measure whether one or zero collapses occur. Put differently, in a GRW universe certain meaningful, factual questions are empirically undecidable. We discuss several types of limitations to knowledge and compare them with those in other (no-collapse) versions of quantum mechanics, such as Bohmian mechanics. Most of our results also apply to observer-induced collapses as in orthodox quantum mechanics (as opposed to the spontaneous collapses of GRW theory).

  13. Construction of a paired wave function for spinless electrons at filling fraction ?=2/5

    NASA Astrophysics Data System (ADS)

    Simon, Steven H.; Rezayi, E. H.; Cooper, N. R.; Berdnikov, I.

    2007-02-01

    We construct a wave function, generalizing the well-known Moore-Read Pfaffian, that describes spinless electrons at filling fraction ?=2/5 (or bosons at filling fraction ?=2/3 ) as the ground state of a very simple three body potential. We find, analogous to the Pfaffian, that when quasiholes are added there is a ground state degeneracy which can be identified as zero modes of the quasiholes. The zero modes are identified as having semionic statistics. We write this wave function as a correlator of the Virasoro minimal model conformal field theory M(5,3) . Since this model is nonunitary, we conclude that this wave function is likely a quantum critical state. Nonetheless, we find that the overlaps of this wave function with exact diagonalizations in the lowest and first excited Landau level are very high, suggesting that this wave function may have experimental relevance for some transition that may occur in that regime.

  14. Impact of Mutual Coupling in Leaky Wave Enhanced Imaging Arrays

    Microsoft Academic Search

    Nuria Llombart; Andrea Neto; Giampiero Gerini; Magnus Bonnedal; Peter De Maagt

    2008-01-01

    The impact of mutual coupling between neighboring radiators in an imaging array configuration in the presence of a dielectric super-layer is investigated. The super-layer generally aims at increasing the directivity of each element of the array. However, here it is shown that the directivity of the embedded element patterns are reduced by a high level of mutual coupling. Thus a

  15. Experimental investigation of the stress wave propagation inside a granular column impacted by a shock wave

    NASA Astrophysics Data System (ADS)

    Belov, E.; Blachman, M.; Britan, A.; Sadot, O.; Ben-Dor, G.

    2015-02-01

    A simple experimental technique, based on pressure transducers, capable of measuring the stress wave that propagates along the solid phase of a granular column after being hit head-on by a plane shock wave is presented. The technique is based on installing couples of gauges at different cross-sections along the granular column in such a way that one transducer measures the overall pressure acting on it while the other measures only the pressure exerted on it by the gaseous phase of the granular column. By means of the presented experimental technique the time histories of the stresses normal to the shock tube walls and data on the stress wave attenuation as it propagates downstream towards the shock tube end wall were obtained.

  16. In situ measurements of impact-induced pressure waves in sandstone targets

    NASA Astrophysics Data System (ADS)

    Hoerth, Tobias; Schäfer, Frank; Nau, Siegfried; Kuder, Jürgen; Poelchau, Michael H.; Thoma, Klaus; Kenkmann, Thomas

    2014-10-01

    In the present study we introduce an innovative method for the measurement of impact-induced pressure waves within geological materials. Impact experiments on dry and water-saturated sandstone targets were conducted at a velocity of 4600 m/s using 12 mm steel projectiles to investigate amplitudes, decay behavior, and speed of the waves propagating through the target material. For this purpose a special kind of piezoresistive sensor capable of recording transient stress pulses within solid brittle materials was developed and calibrated using a Split-Hopkinson pressure bar. Experimental impact parameters (projectile size and speed) were kept constant and yielded reproducible signal curves in terms of rise time and peak amplitudes. Pressure amplitudes decreased by 3 orders of magnitude within the first 250 mm (i.e., 42 projectile radii). The attenuation for water-saturated sandstone is higher compared to dry sandstone which is attributed to dissipation effects caused by relative motion between bulk material and interstitial water. The proportion of the impact energy radiated as seismic energy (seismic efficiency) is in the order of 10-3. The present study shows the feasibility of real-time measurements of waves caused by hypervelocity impacts on geological materials. Experiments of this kind lead to a better understanding of the processes in the crater subsurface during a hypervelocity impact.

  17. A Hadron-Quark Vertex Function:. Interconnection Between 3d and 4d Wave Functions

    NASA Astrophysics Data System (ADS)

    Mitra, A. N.; Bhatnagar, S.

    The interrelation between the 4D and 3D forms of the Bethe-Salpeter equation (BSE) with a kernel K (hat q, hat q') which depends on the relative four-momenta, hat q? =q? -P dot qP? /P2 orthogonal to P? is exploited to obtain a hadron-quark vertex function of the Lorentz-invariant form ? (hat q) =D (hat q2)? ? (hat q). The denominator function D (hat q2) is universal and controls the 3D BSE, which provides the mass spectra with the eigenfunctions ? (hat q). The vertex function, directly related to the 4D wave function ? which satisfies a corresponding BSE, defines a natural off-shell extension over the whole of four-momentum space, and provides the basis for the evaluation of transition amplitudes via appropriate quark-loop digrams. The key role of the quantity hat q2 in this formalism is clarified in relation to earlier approaches, in which the applications of this quantity had mostly been limited to the mass shell (q · P = 0). Two applications (fP values for P-> lbar l and F? for ?0 ? ??) are sketched as illustrations of this formalism, and attention is drawn to the problem of complex amplitudes for bigger quark loops with more hadrons, together with the role of the D (hat q) function in overcoming this problem.

  18. Hydrodynamic waves and correlation functions in dusty plasmas

    Microsoft Academic Search

    Xiaogang Wang; A. Bhattacharjee

    1997-01-01

    A hydrodynamic description of strongly coupled dusty plasmas is given when physical quantities vary slowly in space and time and the system can be assumed to be in local thermodynamic equilibrium. The linear waves in such a system are analyzed. In particular, a dispersion equation is derived for low-frequency dust acoustic waves, including collisional damping effects, and compared with experimental

  19. Hydrodynamic Waves and Correlation Functions in Dusty Plasmas

    Microsoft Academic Search

    A. Bhattacharjee; Xiaogang Wang

    1997-01-01

    A hydrodynamic description of strongly coupled dusty plasmas is given when physical quantities vary slowly in space and time and the system can be assumed to be in local thermodynamic equilibrium. The linear waves in such a system are analyzed. In particular, a dispersion equation is derived for low-frequency dust acoustic waves, including collisional damping effects, and compared with experimental

  20. Response Functions of Spiral Wave Solutions of the Complex

    E-print Network

    Biktashev, Vadim N.

    ­dependent external forcing. The typical effects of the perturbation on the stable invariant manifold of spiral waves are (i) displacement of the manifold, (ii) perturbed dynamics along this manifold. The latter is a slow change of previously constant parameters R and \\Phi, i.e. spatial and temporal drift of the spiral wave

  1. The East Atlantic - West Russia Teleconnection in the North Atlantic: Climate Impact and Relation to Rossby Wave Propagation

    NASA Technical Reports Server (NTRS)

    Lim, Young-Kwon

    2014-01-01

    Large-scale winter teleconnection of the East Atlantic - West Russia (EA-WR) over the Atlantic and surrounding regions is examined in order to quantify its impacts on temperature and precipitation and identify the physical mechanisms responsible for its existence. A rotated empirical orthogonal function (REOF) analysis of the upper-tropospheric monthly height field captures successfully the EA-WR pattern and its interannual variation, with the North Atlantic Oscillation as the first mode. EA-WRs climate impact extends from eastern North America to Eurasia. The positive (negative) EA-WR produces positive (negative) temperature anomalies over the eastern US, western Europe and Russia east of Caspian Sea, with negative (positive) anomalies over eastern Canada, eastern Europe including Ural Mountains and the Middle East. These anomalies are largely explained by lower-tropospheric temperature advections. Positive (negative) precipitation anomalies are found over the mid-latitude Atlantic and central Russia around 60E, where lower-level cyclonic (anticyclonic) circulation anomaly is dominant. The eastern Canada and the western Europe are characterized by negative (positive) precipitation anomalies.The EA-WR is found to be closely associated with Rossby wave propagation. Wave activity fluxes show that it is strongly tied to large-scale stationary waves. Furthermore, a stationary wave model (SWM) forced with vorticity transients in the mid-latitude Atlantic (approximately 40N) or diabatic heat source over the subtropical Atlantic near the Caribbean Sea produces well-organized EA-WR-like wave patterns, respectively. Sensitivity tests with the SWM indicate improvement in the simulation of the EA-WR when the mean state is modified to have a positive NAO component that enhances upper-level westerlies between 40-60N.

  2. Spontaneous generation and impact of inertia-gravity waves in a stratified, two-layer shear flow

    E-print Network

    Williams, Paul

    Spontaneous generation and impact of inertia-gravity waves in a stratified, two-layer shear flow P December 2003. [1] Inertia-gravity waves exist ubiquitously throughout the stratified parts inertia-gravity waves are generated as spontaneous adjustment radiation by an evolving large- scale mode

  3. Impact of a simple parameterization of convective gravity-wave drag in a stratosphere-troposphere general circulation model

    E-print Network

    Paris-Sud XI, Université de

    Impact of a simple parameterization of convective gravity-wave drag in a stratosphere to take into account the vertical momentum transfer through the gravity waves excited by deep convection of accurate global climate models. The orographic gravity waves' generation and mech- anism are now well

  4. ENVIRONMENTAL QUESTIONS RELATED TO POINT-ABSORBING LINEAR WAVE-GENERATORS: IMPACT, EFFECTS AND FOULING

    Microsoft Academic Search

    Jan Sundberg; Olivia Langhamer

    In this paper we describe general environmental aspect that has to be considered for tidal- and wave power project, issues likely to appear in Environ- mental Impact Assessments. We mainly focus on point absorber techniques but most questions apply independent of technology. The environmental aspect covered focus mainly on marine biological questions that appears to be unavoidable as aspects to

  5. Crack detection in a wheel end spindle using wave propagation via modal impacts and piezo actuation

    Microsoft Academic Search

    Spencer Ackers; Ronald Evans; Timothy Johnson; Harold Kess; Jonathan White; Douglas E. Adams; Pam Brown

    2006-01-01

    This research demonstrates two methodologies for detecting cracks in a metal spindle housed deep within a vehicle wheel end assembly. First, modal impacts are imposed on the hub of the wheel in the longitudinal direction to produce broadband elastic wave excitation spectra out to 7000 Hz. The response data on the flange is collected using 3000 Hz bandwidth accelerometers. It

  6. Electron-impact excitation-autoionization of helium in the S-wave limit

    SciTech Connect

    Horner, Daniel A.; McCurdy, C. William; Rescigno, Thomas N.

    2004-10-01

    Excitation of the autoionizing states of helium by electron impact is shown in calculations in the s-wave limit to leave a clear signature in the singly differential cross section for the (e,2e) process. It is suggested that such behavior should be seen generally in (e,2e) experiments on atoms that measure the single differential cross section.

  7. Impact of current-wave interaction on storm surge simulation: A case study for Hurricane Bob

    E-print Network

    Chen, Changsheng

    Impact of current-wave interaction on storm surge simulation: A case study for Hurricane Bob,2 Received 2 January 2013; revised 5 April 2013; accepted 18 April 2013; published 30 May 2013. [1] Hurricane was developed and applied to simulate and examine the coastal ocean responses to Hurricane Bob. Results from

  8. Impact of the atmospheric climate modes on wave climate in the North Atlantic

    NASA Astrophysics Data System (ADS)

    Martínez-Asensio, Adrián; Tsimplis, Michael N.; Marcos, Marta; Feng, Xiangbo; Gomis, Damià; Jordà, Gabriel; Josey, Simon

    2014-05-01

    This study establishes the relationships between the mean modes of atmospheric variability in the North Atlantic and present wave climate. The modes considered, namely the North Atlantic Oscillation (NAO), the East Atlantic pattern (EA), the East Atlantic Western Russian pattern (EA/WR) and the Scandinavian pattern (SCAN), are obtained from the NOAA Climate Prediction Centre. The wave data sets used consist of buoy records and two high-resolution simulations of significant wave height (SWH), mean wave period (MWP) and mean wave direction (MWD) forced with ERA-40 (1958-2002) and ERA-INTERIM (1989-2008) wind fields. The results show the winter impact of each mode on wave parameters which are discussed regionally. The NAO and EA pattern increase winter SWH up to 1 m per unit index at the Scottish and Spanish coasts, respectively, during their positive phase; while EA pattern causes clockwise changes of winter MWD up to more than 60 degrees per unit index at the Bay of Biscay during its negative phase. EA/WR and SCAN patterns have a weaker impact.

  9. Characteristics of the Wave Function of Coupled Oscillators in Semiquantum Chaos

    E-print Network

    Gang Wu; Jinming Dong

    2007-07-30

    Using the method of adiabatic invariants and the Born-Oppenheimer approximation, we have successfully got the excited-state wave functions for a pair of coupled oscillators in the so-called \\textit{semiquantum chaos}. Some interesting characteristics in the \\textit{Fourier spectra} of the wave functions and its \\textit{Correlation Functions} in the regular and chaos states have been found, which offers a new way to distinguish the regular and chaotic states in quantum system.

  10. The impact of consecutive freshwater trimix dives at altitude on human cardiovascular function.

    PubMed

    Lozo, Mislav; Madden, Dennis; Gunjaca, Grgo; Ljubkovic, Marko; Marinovic, Jasna; Dujic, Zeljko

    2015-03-01

    Self-contained underwater breathing apparatus (SCUBA) diving is regularly associated with numerous asymptomatic changes in cardiovascular function. Freshwater SCUBA diving presents unique challenges compared with open sea diving related to differences in water density and the potential for dive locations at altitude. The aim of this study was to evaluate the impact of freshwater trimix diving at altitude on human cardiovascular function. Ten divers performed two dives in consecutive days at 294 m altitude with the surface interval of 24 h. Both dives were at a depth of 45 m with total dive time 29 and 26 min for the first and second dive, respectively. Assessment of venous gas embolization, hydration status, cardiac function and arterial stiffness was performed. Production of venous gas emboli was low, and there were no significant differences between the dives. After the first dive, diastolic blood pressure was significantly reduced, which persisted up to 24 h. Left ventricular stroke volume decreased, and heart rate increased after both dives. Pulse wave velocity was unchanged following the dives. However, the central and peripheral augmentation index became more negative after both dives, indicating reduced wave reflection. Ejection duration and round trip travel time were prolonged 24 h after the first dive, suggesting longer-lasting suppression of cardiac and endothelial function. This study shows that freshwater trimix dives with conservative profiles and low venous gas bubble loads can result in multiple asymptomatic acute cardiovascular changes some of which were present up to 24 h after dive. PMID:24528802

  11. Decomposition of the unsteady wave patterns for Bessho form translating-pulsating source green function

    NASA Astrophysics Data System (ADS)

    Xiao, Wenbin; Dong, Wencai

    2014-10-01

    In order to interpret the physical feature of Bessho form translating-pulsating source Green function, the phase function is extracted from the integral representation and stationary-phase analysis is carried out in this paper. The complex characteristics of the integral variable and segmentation of the integral intervals are discussed in m complex plane. In ? space, the interval [-?/2+ ?, -?/2+ ?-i ?] is dominant in the near-field flow, and there is a one-to-one correspondence between the real intervals in m space and the unsteady wave patterns in far field. If 4 ?>1 ( ? is the Brard number), there are three kinds of propagation wave patterns such as ring-fan wave pattern, fan wave pattern and inner V wave pattern, and if 0<4 ?<1, a ring wave pattern, an outer V and inner V wave pattern are presented in far field. The ring-fan or ring wave pattern corresponds to the interval [-?+ ?, -?/2+ ?] for integral terms about k 2, and the fan or outer V wave pattern and inner V wave pattern correspond to [-?+ ?, -?/2) and (-?/2, -?/2+ ?] respectively for terms about k 1. Numerical result shows that it is beneficial to decompose the unsteady wave patterns under the condition of ??0 by converting the integral variable ? to m. In addition, the constant-phase curve equations are derived when the source is performing only pulsating or translating.

  12. Longitudinal wave function control in single quantum dots with an applied magnetic field

    PubMed Central

    Cao, Shuo; Tang, Jing; Gao, Yunan; Sun, Yue; Qiu, Kangsheng; Zhao, Yanhui; He, Min; Shi, Jin-An; Gu, Lin; Williams, David A.; Sheng, Weidong; Jin, Kuijuan; Xu, Xiulai

    2015-01-01

    Controlling single-particle wave functions in single semiconductor quantum dots is in demand to implement solid-state quantum information processing and spintronics. Normally, particle wave functions can be tuned transversely by an perpendicular magnetic field. We report a longitudinal wave function control in single quantum dots with a magnetic field. For a pure InAs quantum dot with a shape of pyramid or truncated pyramid, the hole wave function always occupies the base because of the less confinement at base, which induces a permanent dipole oriented from base to apex. With applying magnetic field along the base-apex direction, the hole wave function shrinks in the base plane. Because of the linear changing of the confinement for hole wave function from base to apex, the center of effective mass moves up during shrinking process. Due to the uniform confine potential for electrons, the center of effective mass of electrons does not move much, which results in a permanent dipole moment change and an inverted electron-hole alignment along the magnetic field direction. Manipulating the wave function longitudinally not only provides an alternative way to control the charge distribution with magnetic field but also a new method to tune electron-hole interaction in single quantum dots. PMID:25624018

  13. Coherent molecular transistor: Control through variation of the gate wave function

    SciTech Connect

    Ernzerhof, Matthias, E-mail: Matthias.Ernzerhof@UMontreal.ca [Département de Chimie, Université de Montréal, C.P. 6128 Succursale A, Montréal, Quebec H3C 3J7 (Canada)] [Département de Chimie, Université de Montréal, C.P. 6128 Succursale A, Montréal, Quebec H3C 3J7 (Canada)

    2014-03-21

    In quantum interference transistors (QUITs), the current through the device is controlled by variation of the gate component of the wave function that interferes with the wave function component joining the source and the sink. Initially, mesoscopic QUITs have been studied and more recently, QUITs at the molecular scale have been proposed and implemented. Typically, in these devices the gate lead is subjected to externally adjustable physical parameters that permit interference control through modifications of the gate wave function. Here, we present an alternative model of a molecular QUIT in which the gate wave function is directly considered as a variable and the transistor operation is discussed in terms of this variable. This implies that we specify the gate current as well as the phase of the gate wave function component and calculate the resulting current through the source-sink channel. Thus, we extend on prior works that focus on the phase of the gate wave function component as a control parameter while having zero or certain discrete values of the current. We address a large class of systems, including finite graphene flakes, and obtain analytic solutions for how the gate wave function controls the transistor.

  14. Longitudinal wave function control in single quantum dots with an applied magnetic field

    E-print Network

    Shuo Cao; Jing Tang; Yunan Gao; Yue Sun; Kangsheng Qiu; Yanhui Zhao; Min He; Jin-An Shi; Lin Gu; David A. Williams; Weidong Sheng; Kuijuan Jin; Xiulai Xu

    2015-01-29

    Controlling single-particle wave functions in single semiconductor quantum dots is in demand to implement solid-state quantum information processing and spintronics. Normally, particle wave functions can be tuned transversely by an perpendicular magnetic field. We report a longitudinal wave function control in single quantum dots with a magnetic field. For a pure InAs quantum dot with a shape of pyramid or truncated pyramid, the hole wave function always occupies the base because of the less confinement at base, which induces a permanent dipole oriented from base to apex. With applying magnetic field along the base-apex direction, the hole wave function shrinks in the base plane. Because of the linear changing of the confinement for hole wave function from base to apex, the center of effective mass moves up during shrinking process. Due to the uniform confine potential for electrons, the center of effective mass of electrons does not move much, which results in a permanent dipole moment change and an inverted electron-hole alignment along the magnetic field direction. Manipulating the wave function longitudinally not only provides an alternative way to control the charge distribution with magnetic field but also a new method to tune electron-hole interaction in single quantum dots.

  15. On the accuracy of density functional theory and wave function methods for calculating vertical ionization energies

    NASA Astrophysics Data System (ADS)

    McKechnie, Scott; Booth, George H.; Cohen, Aron J.; Cole, Jacqueline M.

    2015-05-01

    The best practice in computational methods for determining vertical ionization energies (VIEs) is assessed, via reference to experimentally determined VIEs that are corroborated by highly accurate coupled-cluster calculations. These reference values are used to benchmark the performance of density functional theory (DFT) and wave function methods: Hartree-Fock theory, second-order Møller-Plesset perturbation theory, and Electron Propagator Theory (EPT). The core test set consists of 147 small molecules. An extended set of six larger molecules, from benzene to hexacene, is also considered to investigate the dependence of the results on molecule size. The closest agreement with experiment is found for ionization energies obtained from total energy difference calculations. In particular, DFT calculations using exchange-correlation functionals with either a large amount of exact exchange or long-range correction perform best. The results from these functionals are also the least sensitive to an increase in molecule size. In general, ionization energies calculated directly from the orbital energies of the neutral species are less accurate and more sensitive to an increase in molecule size. For the single-calculation approach, the EPT calculations are in closest agreement for both sets of molecules. For the orbital energies from DFT functionals, only those with long-range correction give quantitative agreement with dramatic failing for all other functionals considered. The results offer a practical hierarchy of approximations for the calculation of vertical ionization energies. In addition, the experimental and computational reference values can be used as a standardized set of benchmarks, against which other approximate methods can be compared.

  16. On the accuracy of density functional theory and wave function methods for calculating vertical ionization energies.

    PubMed

    McKechnie, Scott; Booth, George H; Cohen, Aron J; Cole, Jacqueline M

    2015-05-21

    The best practice in computational methods for determining vertical ionization energies (VIEs) is assessed, via reference to experimentally determined VIEs that are corroborated by highly accurate coupled-cluster calculations. These reference values are used to benchmark the performance of density functional theory (DFT) and wave function methods: Hartree-Fock theory, second-order Møller-Plesset perturbation theory, and Electron Propagator Theory (EPT). The core test set consists of 147 small molecules. An extended set of six larger molecules, from benzene to hexacene, is also considered to investigate the dependence of the results on molecule size. The closest agreement with experiment is found for ionization energies obtained from total energy difference calculations. In particular, DFT calculations using exchange-correlation functionals with either a large amount of exact exchange or long-range correction perform best. The results from these functionals are also the least sensitive to an increase in molecule size. In general, ionization energies calculated directly from the orbital energies of the neutral species are less accurate and more sensitive to an increase in molecule size. For the single-calculation approach, the EPT calculations are in closest agreement for both sets of molecules. For the orbital energies from DFT functionals, only those with long-range correction give quantitative agreement with dramatic failing for all other functionals considered. The results offer a practical hierarchy of approximations for the calculation of vertical ionization energies. In addition, the experimental and computational reference values can be used as a standardized set of benchmarks, against which other approximate methods can be compared. PMID:26001454

  17. Impact of non-hydrostatic effects and trapped lee waves on mountain wave drag

    E-print Network

    Wirosoetisno, Djoko

    sheared flow 1234567 15578379AB72C4DE FAAAE9A74742AA1AAA 853AD!AEDE" #$92DC3345A7!!753CAE9A328879A677A%&7 in directionally sheared flow C. L. Yu and M. A. C. Teixeira Department of Meteorology, University of Reading gravity wave drag produced in flow over an axisymmetric mountain when both vertical wind shear and non

  18. Degenerate RS perturbation theory. [Rayleigh-Schroedinger energies and wave functions

    NASA Technical Reports Server (NTRS)

    Hirschfelder, J. O.; Certain, P. R.

    1974-01-01

    A concise, systematic procedure is given for determining the Rayleigh-Schroedinger energies and wave functions of degenerate states to arbitrarily high orders even when the degeneracies of the various states are resolved in arbitrary orders. The procedure is expressed in terms of an iterative cycle in which the energy through the (2n + 1)-th order is expressed in terms of the partially determined wave function through the n-th order. Both a direct and an operator derivation are given. The two approaches are equivalent and can be transcribed into each other. The direct approach deals with the wave functions (without the use of formal operators) and has the advantage that it resembles the usual treatment of nondegenerate perturbations and maintains close contact with the basic physics. In the operator approach, the wave functions are expressed in terms of infinite-order operators which are determined by the successive resolution of the space of the zeroth-order functions.

  19. Spectrum and Wave Functions of Excited States in Lattice Gauge Theory

    E-print Network

    H. Kroger; A. Hosseinizadeh; J. F. Laprise; J. Kroger

    2009-02-17

    We suggest a new method to compute the spectrum and wave functions of excited states. We construct a stochastic basis of Bargmann link states, drawn from a physical probability density distribution and compute transition amplitudes between stochastic basis states. From such transition matrix we extract wave functions and the energy spectrum. We apply this method to $U(1)_{2+1}$ lattice gauge theory. As a test we compute the energy spectrum, wave functions and thermodynamical functions of the electric Hamiltonian and compare it with analytical results. We find excellent agreement. We observe scaling of energies and wave functions in the variable of time. We also present first results on a small lattice for the full Hamiltonian including the magnetic term.

  20. The Hartle-Hawking wave function in 2d causal set quantum gravity

    E-print Network

    Lisa Glaser; Sumati Surya

    2014-11-13

    We define the Hartle-Hawking no-boundary wave function for causal set quantum gravity over the discrete analogs of spacelike hypersurfaces. Using Markov Chain Monte Carlo and numerical integration methods we analyse this wave function in non perturbative 2d causal set quantum gravity. Our results provide new insights into the role of quantum gravity in the observable universe. We find that non-manifold contributions to the Hartle-Hawking wave function can play a significant role. These discrete geometries exhibit a rapid spatial expansion with respect to the proper time and also possess a spatial homogeneity consistent with our current understanding of the observable universe.

  1. Matrix-Product based Projected Wave Functions Ansatz for Quantum Many-Body Ground States

    E-print Network

    Chou, Chung-Pin; Lee, Ting-Kuo

    2012-01-01

    We develop a new projected wave function approach which is based on projection operators in the form of matrix-product operators (MPOs). Our approach allows to variationally improve the short range entanglement of a given trial wave function by optimizing the matrix elements of the MPOs while the long range entanglement is contained in the initial guess of the wave function. The optimization is performed using standard variational Monte Carlo techniques. We demonstrate the efficiency of our approach by considering a one-dimension model of interacting spinless fermions. In addition, we indicate how to generalize this approach to higher dimensions using projection operators which are based on tensor products.

  2. Probability density functions for non-linear random waves and responses

    Microsoft Academic Search

    Ulla Botelho Machado

    2003-01-01

    Non-linear waves have been a research topic for a long time, but have not yet entered common ocean engineering practice. In this article the problem of calculating the probability density function (pdf) for non-linear waves is investigated. The ‘saddle point approximation’ is applied to a second-order wave model to estimate the pdf. The performance of the approximation is compared with

  3. Semiempirical dissipation source functions for ocean waves: Part I, definition, calibration and validation

    Microsoft Academic Search

    Fabrice Ardhuin; Jean-Francois Filipot; Rudy Magne; Erick Rogers; Alexander Babanin; Pierre Queffeulou; Lotfi Aouf; Jean-Michel Lefevre; Aron Roland; Andre van der Westhuysen; Fabrice Collard

    2009-01-01

    New parameterizations for the spectra dissipation of wind-generated waves are\\u000aproposed. The rates of dissipation have no predetermined spectral shapes and\\u000aare functions of the wave spectrum and wind speed and direction, in a way\\u000aconsistent with observation of wave breaking and swell dissipation properties.\\u000aNamely, the swell dissipation is nonlinear and proportional to the swell\\u000asteepness, and dissipation due

  4. Wave diffraction and resolution of mantle transition zone discontinuities in receiver function imaging

    NASA Astrophysics Data System (ADS)

    Deng, Kai; Zhou, Ying

    2015-06-01

    The structure of seismic discontinuities in the mantle transition zone at depths of about 400 and 670 km provides important constraints on mantle convection as the associated mineral phase transformations are sensitive to thermal perturbations. Teleseismic P-to-S receiver functions have been widely used to map the depths of the two discontinuities. In this study, we investigate the resolution of receiver functions in imaging topographic variations of the 400-km and 670-km discontinuities based on wave propagation simulations using a Spectral Element Method (SEM). We investigate wave diffraction effects on direct P waves as well as P-to-S converted waves by varying the length scale of topography of the two discontinuities. We observe strong wave diffractional effects in both P waves and teleseismic receiver functions at periods of ˜10 to 20 s. Ray theory overpredicts traveltime anomalies by a factor of 2-5 when the topography length scale is about 400 km. In addition, ray-theoretical predictions are out of phase with measurements which indicates that locations of small-scale topographic variations can not be resolved using ray theory. The observed traveltime anomalies further reduce to 10-20 per cent of ray-theoretical predictions when the topography length scale reduces to about 200 km. We calculate 2-D boundary sensitivity kernels for direct P waves as well as receiver functions. In general, calculations based Born sensitivity kernels fit the `ground-truth' SEM measurements very well. They account for wave diffraction effects as well as phase interactions such as P and pP waves arriving in P-wave coda. 3-D wavespeed structure in the upper mantle beneath seismic stations may introduce significant traveltime anomalies on P waves and transition zone receiver functions. We show that traveltime corrections at periods of about 10 to 20 s are frequency dependent when the size of the anomalies becomes less than 500 km.

  5. Alleviation of the Fermion-sign problem by optimization of many-body wave functions C. J. Umrigar,1

    E-print Network

    Boyer, Edmond

    Alleviation of the Fermion-sign problem by optimization of many-body wave functions C. J. Umrigar,1 eigenstates. For Fermionic systems, the antisymmetry constraint leads to the Fermion-sign problem that forces efficiency. Form of wave functions. We employ N-electron wave functions which depend on Nopt variational

  6. A test of a mechanical multi-impact shear-wave seismic source

    USGS Publications Warehouse

    Worley, David M.; Odum, Jack K.; Williams, Robert A.; Stephenson, William J.

    2001-01-01

    We modified two gasoline-engine-powered earth tampers, commonly used as compressional-(P) wave seismic energy sources for shallow reflection studies, for use as shear(S)-wave energy sources. This new configuration, termed ?Hacker? (horizontal Wacker?), is evaluated as an alternative to the manual sledgehammer typically used in conjunction with a large timber held down by the front wheels of a vehicle. The Hacker maximizes the use of existing equipment by a quick changeover of bolt-on accessories as opposed to the handling of a separate source, and is intended to improve the depth of penetration of S-wave data by stacking hundreds of impacts over a two to three minute period. Records were made with a variety of configurations involving up to two Hackers simultaneously then compared to a reference record made with a sledgehammer. Preliminary results indicate moderate success by the higher amplitude S-waves recorded with the Hacker as compared to the hammer method. False triggers generated by the backswing of the Hacker add unwanted noise and we are currently working to modify the device to eliminate this effect. Correlation noise caused by insufficient randomness of the Hacker impact sequence is also a significant noise problem that we hope to reduce by improving the coupling of the Hacker to the timber so that the operator has more control over the impact sequence.

  7. Analytical and numerical studies of angular correlation function of waves scattered from randomly distributed cylinders

    Microsoft Academic Search

    Yasuo Kuga; Guifu Zhang; Ji-Hae Yea; Akira Ishimaru

    1998-01-01

    The analytical solution for the angular correlation function of scattered waves from randomly distributed infinitely long cylinders is obtained using the second-order approximation with a modified attenuation coefficient. The approach is based on the coherent summation of the scattered waves which preserves the interference effects such as backscattering enhancement. The modification of the transport attenuation coefficient includes the contribution due

  8. Asymmetry in Directional Spreading Function of Random Waves due to Refraction

    E-print Network

    Haller, Merrick

    , 1970 , the Joint North Sea Wave Project JONSWAP spectrum Hassel- mann et al. 1973 , and the TEXEL storm. The wave energy distribution in frequency and direction is given by the directional spectrum S f , , which can be represented as the product of the frequency spectrum S f and the directional spreading function

  9. Moho map of South America from receiver functions and surface waves

    E-print Network

    van der Lee, Suzan

    Moho map of South America from receiver functions and surface waves Simon Lloyd,1 Suzan van der Lee the crustal thickness between the station locations, we jointly invert these Moho point constraints, Rayleigh wave group velocities, and regional S and Rayleigh waveforms for a continuous map of Moho depth

  10. Roles of photon and vector meson wave functions in photo- and electro-production processes

    NASA Astrophysics Data System (ADS)

    Baltar, Vera L.; Dosch, H. G.; Ferreira, Erasmo

    2004-12-01

    We investigate properties of the overlap of light cone wave functions of the real or virtual photon and of the vector meson that play essential roles in the evaluation of observable quantities in photo- and elecro- production processes. We compare the behaviour of the different several S-wave vector mesons (?, ?, ?, ? and ?).

  11. Real merits of the wind wave model with an optimized source function

    Microsoft Academic Search

    V. G. Polnikov; V. I. Dymov; T. A. Pasechnik; I. V. Lavrenov; Yu. N. Abuzyarov

    2007-01-01

    By means of modification of the wind wave model WAM (Cycle-4), a series of numerical experiments was carried out for verification of a new source function proposed earlier [1]. Verification was done on the basis of comparison of the results of wave simulation for a given wind field with the buoy observation data obtained in three oceanic regions. Estimations of

  12. Roles of photon and vector meson wave functions in photo- and electro-production processes

    Microsoft Academic Search

    Vera L. Baltar; H. G. Dosch; Erasmo Ferreira

    2004-01-01

    We investigate properties of the overlap of light cone wave functions of the real or virtual photon and of the vector meson that play essential roles in the evaluation of observable quantities in photo- and elecro- production processes. We compare the behaviour of the different several S-wave vector mesons (&rgr;, ?, ?, &psgr; and &Ugr;).

  13. Roles of photon and vector meson wave functions in photo- and electro-production processes

    Microsoft Academic Search

    Vera L. Baltar; H. G. Dosch; Erasmo Ferreira

    2004-01-01

    We investigate properties of the overlap of light cone wave functions of the real or virtual photon and of the vector meson that play essential roles in the evaluation of observable quantities in photo- and elecro- production processes. We compare the behaviour of the different several S-wave vector mesons (rho, omega, phi, psi and Upsilon).

  14. Impact of kudzu and puerarin on sperm function.

    PubMed

    Gray, Sandra L; Lackey, Brett R; Boone, William R

    2015-06-01

    The goal of this study was to investigate the impact of kudzu (Pueraria mirifica) and the isoflavone puerarin in functional toxicological tests on spermatozoa and to assess the affinity of extracts and pure isoflavones for estrogen receptor (ER)-alpha and -beta (ER?, ER?) in receptor binding assays. Capacitation, acrosome reaction and chromatin decondensation in spermatozoa were analyzed using microscopic analysis. Kudzu, but not puerarin, reduced motility of sperm. Puerarin reduced the percent spontaneous acrosome reaction in spermatozoa. The pathways used by kudzu that affect sperm function are not fully mirrored by puerarin. Puerarin, kudzu and its other phytoestrogenic components displayed preferential affinity for ER?, however the diverse effects of kudzu and puerarin on sperm function implicate the involvement of multiple signaling systems. PMID:25828059

  15. The Dynamic Dielectric at a Brain Functional Site and an EM Wave Approach to Functional Brain Imaging

    PubMed Central

    Li, X. P.; Xia, Q.; Qu, D.; Wu, T. C.; Yang, D. G.; Hao, W. D.; Jiang, X.; Li, X. M.

    2014-01-01

    Functional brain imaging has tremendous applications. The existing methods for functional brain imaging include functional Magnetic Resonant Imaging (fMRI), scalp electroencephalography (EEG), implanted EEG, magnetoencephalography (MEG) and Positron Emission Tomography (PET), which have been widely and successfully applied to various brain imaging studies. To develop a new method for functional brain imaging, here we show that the dielectric at a brain functional site has a dynamic nature, varying with local neuronal activation as the permittivity of the dielectric varies with the ion concentration of the extracellular fluid surrounding neurons in activation. Therefore, the neuronal activation can be sensed by a radiofrequency (RF) electromagnetic (EM) wave propagating through the site as the phase change of the EM wave varies with the permittivity. Such a dynamic nature of the dielectric at a brain functional site provides the basis for an RF EM wave approach to detecting and imaging neuronal activation at brain functional sites, leading to an RF EM wave approach to functional brain imaging. PMID:25367217

  16. Impact of water saturation on seismoelectric transfer functions: a laboratory study of coseismic phenomenon

    NASA Astrophysics Data System (ADS)

    Bordes, C.; Sénéchal, P.; Barrière, J.; Brito, D.; Normandin, E.; Jougnot, D.

    2015-03-01

    Seismic waves propagating in a porous medium, under favourable conditions, generate measurable electromagnetic fields due to electrokinetic effects. It has been proposed, following experimental and numerical studies, that these so-called `seismoelectromagnetic' couplings depend on pore fluid properties. The theoretical frame describing these phenomena are based on the original Biot's theory, assuming that pores are fluid-filled. We study here the impact of a partially saturated medium on amplitudes of those seismoelectric couplings by comparing experimental data to an effective fluid model. We have built a 1-m-length-scale experiment designed for imbibition and drainage of an homogeneous silica sand; the experimental set-up includes a seismic source, accelerometers, electric dipoles and capacitance probes in order to monitor seismic and seismoelectric fields during water saturation. Apparent velocities and frequency spectra (in the kiloHertz range) are derived from seismic and electrical measurements during experiments in varying saturation conditions. Amplitudes of seismic and seismoelectric waves and their ratios (i.e. transfer functions) are discussed using a spectral analysis performed by continuous wavelet transform. The experiments reveal that amplitude ratios of seismic to coseismic electric signals remain rather constant as a function of the water saturation in the Sw = [0.2-0.9] range, consistently with theoretically predicted transfer functions.

  17. The Impact of Social Disparity on Prefrontal Function in Childhood

    PubMed Central

    Sheridan, Margaret A.; Sarsour, Khaled; Jutte, Douglas; D'Esposito, Mark; Boyce, W. Thomas

    2012-01-01

    The prefrontal cortex (PFC) develops from birth through late adolescence. This extended developmental trajectory provides many opportunities for experience to shape the structure and function of the PFC. To date, a few studies have reported links between parental socioeconomic status (SES) and prefrontal function in childhood, raising the possibility that aspects of environment associated with SES impact prefrontal function. Considering that behavioral measures of prefrontal function are associated with learning across multiple domains, this is an important area of investigation. In this study, we used fMRI to replicate previous findings, demonstrating an association between parental SES and PFC function during childhood. In addition, we present two hypothetical mechanisms by which SES could come to affect PFC function of this association: language environment and stress reactivity. We measured language use in the home environment and change in salivary cortisol before and after fMRI scanning. Complexity of family language, but not the child's own language use, was associated with both parental SES and PFC activation. Change in salivary cortisol was also associated with both SES and PFC activation. These observed associations emphasize the importance of both enrichment and adversity-reduction interventions in creating good developmental environments for all children. PMID:22563395

  18. Time-dependent variational principle with constraints for parametrized wave functions

    SciTech Connect

    Ohta, Katsuhisa [Department of Applied Chemistry, Muroran Institute of Technology, Muroran, Hokkaido 050-8585 (Japan)

    2004-08-01

    The time-dependent variational principle in the stationary action principle form is formulated with constraint conditions for parametrized wave functions. The constraint conditions are classified into the first and the second classes as in Dirac's constrained classical mechanics based on the commutability of operators. If the local bases in the parametrized wave functions construct a complete basis set, the classification of constraints with the commutator becomes equivalent to that with the complex generalized Poisson brackets (CGPB). However, in approximate wave functions with limited variational parameters, the equivalence between the CGPB and the commutator of operators is lost. The first-class constraints and the constants of motion classified with the commutator should be reconsidered as the pseudo-second-class constraints in the approximate wave functions.

  19. Three-body continuum wave functions with a box boundary condition

    E-print Network

    E. Garrido

    2015-05-06

    In this work we investigate the connection between discretized three-body continuum wave functions, in particular via a box boundary condition, and the wave functions computed with the correct asymptotics. The three-body wave functions are in both cases obtained by means of the adiabatic expansion method. The information concerning all the possible incoming and outgoing channels, which appears naturally when the continuum is not discretized, seems to be lost when the discretization is implemented. In this work we show that both methods are fully equivalent, and the full information contained in the three-body wave function is actually preserved in the discrete spectrum. Therefore, in those cases when the asymptotic behaviour is not known analytically, i.e., when the Coulomb interaction is involved, the discretization technique can be safely used.

  20. Bragg scattering as a probe of atomic wave functions and quantum phase transitions in optical lattices

    E-print Network

    Miyake, Hirokazu

    We have observed Bragg scattering of photons from quantum degenerate 87Rb atoms in a three-dimensional optical lattice. Bragg scattered light directly probes the microscopic crystal structure and atomic wave function whose ...

  1. The scattering and shrinking of a Gaussian wave packet by delta function potentials

    E-print Network

    Sun, Fei, S.B. Massachusetts Institute of Technology

    2012-01-01

    In this thesis, we wish to test the hypothesis that scattering by a random potential causes localization of wave functions, and that this localization is governed by the Born postulate of quantum mechanics. We begin with ...

  2. Modifying Measures Based on Differential Item Functioning (DIF) Impact Analyses

    PubMed Central

    Teresi, Jeanne A.; Ramirez, Mildred; Jones, Richard N.; Choi, Seung; Crane, Paul K.

    2014-01-01

    Objectives Measure modification can impact comparability of scores across groups and settings. Changes in items can affect the percent admitting to a symptom. Methods Using item response theory (IRT) methods, well-calibrated items can be used interchangeably, and the exact same item does not have to be administered to each respondent, theoretically permitting wider latitude in terms of modification. Results Recommendations regarding modifications vary, depending on the use of the measure. In the context of research, adjustments can be made at the analytic level by freeing and fixing parameters based on findings of differential item functioning (DIF). The consequences of DIF for clinical decision making depend on whether or not the patient’s performance level approaches the scale decision cutpoint. High-stakes testing may require item removal or separate calibrations to ensure accurate assessment. Discussion Guidelines for modification based on DIF analyses and illustrations of the impact of adjustments are presented. PMID:22422759

  3. How to measure the wave-function absolute squared of a moving particle by using mirrors

    E-print Network

    Volker Hannstein; Gerhard C. Hegerfeldt

    2007-06-19

    We consider a slow particle with wave function $\\psi_t(\\vec{x})$, moving freely in some direction. A mirror is briefly switched on around a time $T$ and its position is scanned. It is shown that the measured reflection probability then allows the determination of $|\\psi_T(\\vec{x})|^2$. Experimentally available atomic mirrors should make this method applicable to the center-of-mass wave function of atoms with velocities in the cm/s range.

  4. Convergence of repeated quantum non-demolition measurements and wave function collapse

    E-print Network

    Michel Bauer; Denis Bernard

    2011-10-25

    Motivated by recent experiments on quantum trapped fields, we give a rigorous proof that repeated indirect quantum non-demolition (QND) measurements converge to the collapse of the wave function as predicted by the postulates of quantum mechanics for direct measurements. We also relate the rate of convergence toward the collapsed wave function to the relative entropy of each indirect measurement, a result which makes contact with information theory.

  5. Critical wave functions and a Cantor-set spectrum of a one-dimensional quasicrystal model

    Microsoft Academic Search

    Mahito Kohmoto; Bill Sutherland; Chao Tang

    1987-01-01

    The electronic properties of a tight-binding model which possesses two types of hopping matrix element (or on-site energy) arranged in a Fibonacci sequence are studied. The wave functions are either self-similar (fractal) or chaotic and show ``critical'' (or ``exotic'') behavior. Scaling analysis for the self-similar wave functions at the center of the band and also at the edge of the

  6. Alpha-particle formation and decay rates from Skyrme-HFB wave functions

    NASA Astrophysics Data System (ADS)

    Ward, D. E.; Carlsson, B. G.; Åberg, S.

    2014-05-01

    ? decay is treated microscopically, where the unstable mother nucleus and residual daughter nucleus are described using Hartree-Fock-Bogoliubov (HFB) wave functions, obtained with the Skyrme effective interaction. From these wave functions the amplitude for forming ? particles in the mother nucleus is computed. Two different Skyrme parametrizations with different pairing properties are compared, and we find good agreement with experiment for relative decay rates in both cases. The absolute values of the decay rates are underestimated.

  7. EDF: Computing electron number probability distribution functions in real space from molecular wave functions

    NASA Astrophysics Data System (ADS)

    Francisco, E.; Pendás, A. Martín; Blanco, M. A.

    2008-04-01

    Given an N-electron molecule and an exhaustive partition of the real space ( R) into m arbitrary regions ?,?,…,? ( ?i=1m?=R), the edf program computes all the probabilities P(n,n,…,n) of having exactly n electrons in ?, n electrons in ?,…, and n electrons ( n+n+⋯+n=N) in ?. Each ? may correspond to a single basin (atomic domain) or several such basins (functional group). In the later case, each atomic domain must belong to a single ?. The program can manage both single- and multi-determinant wave functions which are read in from an aimpac-like wave function description ( .wfn) file (T.A. Keith et al., The AIMPAC95 programs, http://www.chemistry.mcmaster.ca/aimpac, 1995). For multi-determinantal wave functions a generalization of the original .wfn file has been introduced. The new format is completely backwards compatible, adding to the previous structure a description of the configuration interaction (CI) coefficients and the determinants of correlated wave functions. Besides the .wfn file, edf only needs the overlap integrals over all the atomic domains between the molecular orbitals (MO). After the P(n,n,…,n) probabilities are computed, edf obtains from them several magnitudes relevant to chemical bonding theory, such as average electronic populations and localization/delocalization indices. Regarding spin, edf may be used in two ways: with or without a splitting of the P(n,n,…,n) probabilities into ? and ? spin components. Program summaryProgram title: edf Catalogue identifier: AEAJ_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEAJ_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 5387 No. of bytes in distributed program, including test data, etc.: 52 381 Distribution format: tar.gz Programming language: Fortran 77 Computer: 2.80 GHz Intel Pentium IV CPU Operating system: GNU/Linux RAM: 55 992 KB Word size: 32 bits Classification: 2.7 External routines: Netlib Nature of problem: Let us have an N-electron molecule and define an exhaustive partition of the physical space into m three-dimensional regions. The edf program computes the probabilities P(n,n,…,n)?P({n}) of all possible allocations of n electrons to ?, n electrons to ?,…, and n electrons to ?,{n} being integers. Solution method: Let us assume that the N-electron molecular wave function, ?(1,N), is a linear combination of M Slater determinants, ?(1,N)=?rMC?(1,N). Calling S?rs the overlap matrix over the 3D region ? between the (real) molecular spin-orbitals (MSO) in ?(?1r,…?Nr) and the MSOs in ?,(?1s,…,?Ns), edf finds all the P({n})'s by solving the linear system ?{n}{?kmtkn}P({n})=?r,sMCCdet[?kmtS?rs], where t=1 and t,…,t are arbitrary real numbers. Restrictions: The number of {n} sets grows very fast with m and N, so that the dimension of the linear system (1) soon becomes very large. Moreover, the computer time required to obtain the determinants in the second member of Eq. (1) scales quadratically with M. These two facts limit the applicability of the method to relatively small molecules. Unusual features: Most of the real variables are of precision real*16. Running time: 0.030, 2.010, and 0.620 seconds for Test examples 1, 2, and 3, respectively. References: [1] A. Martín Pendás, E. Francisco, M.A. Blanco, Faraday Discuss. 135 (2007) 423-438. [2] A. Martín Pendás, E. Francisco, M.A. Blanco, J. Phys. Chem. A 111 (2007) 1084-1090. [3] A. Martín Pendás, E. Francisco, M.A. Blanco, Phys. Chem. Chem. Phys. 9 (2007) 1087-1092. [4] E. Francisco, A. Martín Pendás, M.A. Blanco, J. Chem. Phys. 126 (2007) 094102. [5] A. Martín Pendás, E. Francisco, M.A. Blanco, C. Gatti, Chemistry: A European Journal 113 (2007) 9362-9371.

  8. Studying Regional Wave Source Time Functions Using the Empirical Green's Function Method: Application to Central Asia

    NASA Astrophysics Data System (ADS)

    Xie, J.; Schaff, D. P.; Chen, Y.; Schult, F.

    2013-12-01

    Reliably estimated source time functions (STFs) from high-frequency regional waveforms, such as Lg, Pn and Pg, provide important input for seismic source studies, explosion detection and discrimination, and minimization of parameter trade-off in attenuation studies. We have searched for candidate pairs of larger and small earthquakes in and around China that share the same focal mechanism but significantly differ in magnitudes, so that the empirical Green's function (EGF) method can be applied to study the STFs of the larger events. We conducted about a million deconvolutions using waveforms from 925 earthquakes, and screened the deconvolved traces to exclude those that are from event pairs that involved different mechanisms. Only 2,700 traces passed this screening and could be further analyzed using the EGF method. We have developed a series of codes for speeding up the final EGF analysis by implementing automations and user-graphic interface procedures. The codes have been fully tested with a subset of screened data and we are currently applying them to all the screened data. We will present a large number of deconvolved STFs retrieved using various phases (Lg, Pn, Sn and Pg and coda) with information on any directivities, any possible dependence of pulse durations on the wave types, on scaling relations for the pulse durations and event sizes, and on the estimated source static stress drops.

  9. The 1994 heat wave in South Korea: mortality impacts and recurrence probability in a changing climate

    NASA Astrophysics Data System (ADS)

    Kysely, J.; Kim, J.

    2010-03-01

    The study deals with mortality impacts of the July-August 1994 heat wave in the population of South Korea, including the megacity of Seoul (with the population exceeding 10 million for the city and 20 million for the metropolitan area), and estimates recurrence probability of the heat wave in a changing climate in terms of simulations of daily temperature series with a stochastic model. The 1994 heat wave is found exceptional with respect to both climatological characteristics and the mortality effects: significantly elevated mortality occurred in all population groups, including children up to 14 years of age, and the total death toll exceeded 3000 in the Korean population, which ranks the 1994 heat wave among the worst weather-related disasters in East Asia. The estimate represents net excess mortality as no mortality displacement effect appeared. A comparison with other documented natural disasters shows that the death toll of the heat wave was much higher than those of the most disastrous floodings and typhoons over Korean Peninsula in the 20th century. The mortality response was stronger in males than females although males are found to be less vulnerable during average heat waves. A climatological analysis reveals that the July-August 1994 heat wave might be considered an extremely rare event with a return period in the order of hundreds of years if stationarity of temperature time series is assumed. However, under a more realistic assumption of gradual warming related to climate change, recurrence probability of an event analogous to the 1994 heat wave sharply rises for near-future time horizons. If warming of 0.04°C/year is assumed over 2001-2060, the recurrence interval of a very long spell of days with temperature exceeding a high threshold (as in the 1994 heat wave) is estimated to decrease to around 40 (10) years in the 2021-2030 (2041-2050) decade. This emphasizes the need for setting up an efficient heat-watch-warning system in this area in order to reduce human mortality impacts of heat waves.

  10. Properties of traveling waves for integrodifference equations with nonmonotone growth functions

    NASA Astrophysics Data System (ADS)

    Yu, Zhi-Xian; Yuan, Rong

    2012-04-01

    In this paper, we will establish some new properties of traveling waves for integrodifference equations with the nonmonotone growth functions. More precisely, for c ? c *, we show that either {limlimits_{?rightarrow+infty} ?(?)=u*} or {0 < liminflimits_{? rightarrow + infty} ?(?) < u* < limsup limits_{?rightarrow+infty}?(?)? b,} that is, the wave converges to the positive equilibrium or oscillates about it at +?. Sufficient conditions can assure that both results will arise. We can also obtain that any traveling wave with wave speed c > c* possesses exponential decay at -?. These results can be well applied to three types of growth functions arising from population biology. By choosing suitable parameter numbers, we can obtain the existence of oscillating waves. Our analytic results are consistent with some numerical simulations in Kot (J Math Biol 30:413-436, 1992), Li et al. (J Math Biol 58:323-338, 2009) and complement some known ones.

  11. Millimeter-wave nondestructive evaluation of glass fiber/epoxy composites subjected to impact fatigue

    NASA Astrophysics Data System (ADS)

    Radford, Donald W.; Ganchev, Stoyan I.; Qaddoumi, Nasser; Beauregard, Guy; Zoughi, Reza

    1994-09-01

    The useful life of a glass fiber/epoxy composite subjected to impact fatigue loading is an important issue in the future design of numerous industrial components. Lifetime predictions have been a problem particularly due to the difficulties encountered in monitoring damage accumulation in composites. It is hypothesized that there is a build up of micro damage, such as matrix micro-cracks and micro-delaminations, even though there is no apparent change in material compliance. A critical level is finally reached at which time the properties of the composite begin to fall and compliance change is evident. In this study the apparent compliance change and the type of damage accumulation is investigated. To measure the compliance change, a test unit was developed that uses a dynamic load measuring system. The load cell measures the load throughout each impact pulse and the compliance and energy absorbed by the specimen is then related to the recorded curve. Initially no change in the impact pulse was apparent; however, after a finite number of cycles the peak load and area under each impact pulse drop, indicating an increase in compliance. Unfortunately, the impact load does not provide information on the form and degree of damage. Thus, millimeter wave nondestructive investigation is used, in conjunction with impact fatigue tests, to examine microstructural aspects of damage initiation and growth. The millimeter wave scanning technique results in detectable damage growth throughout the impact fatigue test. Damage size and growth patterns specific to composites are obvious, and after significant damage can be related to the observable macro damage. Continued development of these investigative techniques promises to enhance the ability of detecting defects and damage growth in fiber reinforced composite materials as well as improving the understanding of impact fatigue initiation in these complex materials.

  12. Investigation of dam-break induced shock waves impact on a vertical wall

    NASA Astrophysics Data System (ADS)

    Kocaman, Selahattin; Ozmen-Cagatay, Hatice

    2015-06-01

    In the present study, experimental tests and VOF-based CFD simulations concerning impact of dam-break induced shock waves on a vertical wall at downstream end were investigated. New laboratory experiments were carried out in a rectangular flume with a smooth horizontal wet bed for two different tailwater levels. Image processing was used for flow measurement and time evolutions of water levels were determined effectively by means of synchronous recorded video images of the flow. This study scrutinized formation and travelling of negative wave towards upstream direction, which was resulted from the reflection of flood wave against downstream end wall. In numerical simulation, two distinct approaches available in FLOW-3D were used: Reynolds- averaged Navier-Stokes equations (RANS) with the k-? turbulence model and the Shallow Water Equations (SWEs). The measured results were then compared with those of numerical simulations and reasonable agreements were achieved. General agreement between laboratory measurements and RANS solution was better than that of SWE.

  13. Ramp Wave Generation Using Graded Areal Density Ceramic Flyers and the Plate Impact Technique

    NASA Astrophysics Data System (ADS)

    Taylor, Peter; Appleby-Thomas, Gareth; Goff, Michael; Hazell, Paul; Leighs, James; Wood, David

    2013-06-01

    Ramping shock waves of the order ~ 2-4 GPa were generated in Kel-F targets through the use of graded areal density ceramic flyers via the gas gun plate impact technique, with a buffer disc employed between the flyer and the target to eliminate penetration by the ceramic flyer. Ramp wave parameters were varied through alteration of the areal density gradient and the thickness of the buffer disc used. Observations of the ramped shock were undertaken through the use of embedded particle velocity gauges and the results compared with hydrocode calculations. The discussion of results includes details of the magnitude, gradient and planarity of the ramp waves produced at various positions in the target material. The flyers were fabricated from alumina ceramic with the ceramic laser stereo-lithography process. In order to characterise the material for modelling purposes a series of shots were carried out to compare the Hugoniot of this material with conventionally sintered material, these results are presented.

  14. Influence of coastal vegetation on the 2004 tsunami wave impact in west Aceh.

    PubMed

    Laso Bayas, Juan Carlos; Marohn, Carsten; Dercon, Gerd; Dewi, Sonya; Piepho, Hans Peter; Joshi, Laxman; van Noordwijk, Meine; Cadisch, Georg

    2011-11-15

    In a tsunami event human casualties and infrastructure damage are determined predominantly by seaquake intensity and offshore properties. On land, wave energy is attenuated by gravitation (elevation) and friction (land cover). Tree belts have been promoted as "bioshields" against wave impact. However, given the lack of quantitative evidence of their performance in such extreme events, tree belts have been criticized for creating a false sense of security. This study used 180 transects perpendicular to over 100 km on the west coast of Aceh, Indonesia to analyze the influence of coastal vegetation, particularly cultivated trees, on the impact of the 2004 tsunami. Satellite imagery; land cover maps; land use characteristics; stem diameter, height, and planting density; and a literature review were used to develop a land cover roughness coefficient accounting for the resistance offered by different land uses to the wave advance. Applying a spatial generalized linear mixed model, we found that while distance to coast was the dominant determinant of impact (casualties and infrastructure damage), the existing coastal vegetation in front of settlements also significantly reduced casualties by an average of 5%. In contrast, dense vegetation behind villages endangered human lives and increased structural damage. Debris carried by the backwash may have contributed to these dissimilar effects of land cover. For sustainable and effective coastal risk management, location of settlements is essential, while the protective potential of coastal vegetation, as determined by its spatial arrangement, should be regarded as an important livelihood provider rather than just as a bioshield. PMID:22065751

  15. Influence of coastal vegetation on the 2004 tsunami wave impact in west Aceh

    PubMed Central

    Laso Bayas, Juan Carlos; Marohn, Carsten; Dercon, Gerd; Dewi, Sonya; Piepho, Hans Peter; Joshi, Laxman; van Noordwijk, Meine; Cadisch, Georg

    2011-01-01

    In a tsunami event human casualties and infrastructure damage are determined predominantly by seaquake intensity and offshore properties. On land, wave energy is attenuated by gravitation (elevation) and friction (land cover). Tree belts have been promoted as “bioshields” against wave impact. However, given the lack of quantitative evidence of their performance in such extreme events, tree belts have been criticized for creating a false sense of security. This study used 180 transects perpendicular to over 100 km on the west coast of Aceh, Indonesia to analyze the influence of coastal vegetation, particularly cultivated trees, on the impact of the 2004 tsunami. Satellite imagery; land cover maps; land use characteristics; stem diameter, height, and planting density; and a literature review were used to develop a land cover roughness coefficient accounting for the resistance offered by different land uses to the wave advance. Applying a spatial generalized linear mixed model, we found that while distance to coast was the dominant determinant of impact (casualties and infrastructure damage), the existing coastal vegetation in front of settlements also significantly reduced casualties by an average of 5%. In contrast, dense vegetation behind villages endangered human lives and increased structural damage. Debris carried by the backwash may have contributed to these dissimilar effects of land cover. For sustainable and effective coastal risk management, location of settlements is essential, while the protective potential of coastal vegetation, as determined by its spatial arrangement, should be regarded as an important livelihood provider rather than just as a bioshield. PMID:22065751

  16. AN EXPERIMENTAL STUDY OF SHOCK WAVES RESULTING FROM THE IMPACT OF HIGH VELOCITY MISSILES ON ANIMAL TISSUES

    PubMed Central

    Harvey, E. Newton; McMillen, J. Howard

    1947-01-01

    The spark shadowgram method of studying shock waves is described. It has been used to investigate the properties of such waves produced by the impact of a high velocity missile on the surface of water. The method can be adapted for study of behavior of shock waves in tissue by placing the tissue on a water surface or immersing it in water. Spark shadowgrams then reveal waves passing from tissue to water or reflected from tissue surfaces. Reflection and transmission of shock waves from muscle, liver, stomach, and intestinal wall are compared with reflection from non-living surfaces such as gelatin gel, steel, plexiglas, cork, and air. Because of its heterogeneous structure, waves transmitted by tissue are dispersed and appear as a series of wavelets. When the accoustical impedance (density x wave velocity) of a medium is less than that in which the wave is moving, reflection will occur with inversion of the wave; i.e., a high pressure wave will become a low pressure wave. This inversion occurs at an air surface and is illustrated by shadowgrams of reflection from stomach wall, from a segment of colon filled with gas, and from air-filled rubber balloons. Bone (human skull and beef ribs) shows good reflection and some transmission of shock waves. When steel is directly hit by a missile, clearly visible elastic waves pass from metal to water, but a similar direct hit on bone does not result in elastic waves strong enough to be detected by a spark shadowgram. PMID:19871617

  17. The impact of soil degradation on soil functioning in Europe

    NASA Astrophysics Data System (ADS)

    Montanarella, Luca

    2010-05-01

    The European Commission has presented in September 2006 its Thematic Strategy for Soil Protection.The Thematic Strategy for Soil Protection consists of a Communication from the Commission to the other European Institutions, a proposal for a framework Directive (a European law), and an Impact Assessment. The Communication (COM(2006) 231) sets the frame. It defines the relevant soil functions for Europe and identifies the major threats. It explains why further action is needed to ensure a high level of soil protection, sets the overall objective of the Strategy and explains what kind of measures must be taken. It establishes a ten-year work program for the European Commission. The proposal for a framework Directive (COM(2006) 232) sets out common principles for protecting soils across the EU. Within this common framework, the EU Member States will be in a position to decide how best to protect soil and how use it in a sustainable way on their own territory. The Impact Assessment (SEC (2006) 1165 and SEC(2006) 620) contains an analysis of the economic, social and environmental impacts of the different options that were considered in the preparatory phase of the strategy and of the measures finally retained by the Commission. Since 2006 a large amount of new evidence has allowed to further document the extensive negative impacts of soil degradation on soil functioning in Europe. Extensive soil erosion, combined with a constant loss of soil organic carbon, have raised attention to the important role soils are playing within the climate change related processes. Other important processes are related to the loss of soil biodiversity, extensive soil sealing by housing and infrastructure, local and diffuse contamination by agricultural and industrial sources, compaction due to unsustainable agricultural practices and salinization by unsustainable irrigation practices. The extended impact assessment by the European Commission has attempted to quantify in monetary terms the actual economic impact of soil degradation in Europe.The total costs of soil degradation that could be assessed for erosion, organic matter decline, salinisation, landslides and contamination on the basis of available data, would be up to €38 billion annually for EU25. These estimates are necessarily wide ranging due to the lack of sufficient quantitative and qualitative data. Future research activities will have to address, in multidisciplinary teams, the social and economic aspects of soil degradation in Europe, in order to come up with more reliable estimates of the economic impact of soil degradation. A more reliable and updated system of indicators needs to be developed in order to cover the full cycle of the Driving forces-Pressures-State-Impact-Response (DPSIR) framework. Recent developments towards a new soil monitoring system for Europe will be presented as well as some of the recent outputs of the European Soil Data Centre (ESDAC).

  18. Electromechanical Wave Green's Function Estimation from Ambient Electrical Grid Frequency Noise

    E-print Network

    Backhaus, Scott

    2011-01-01

    Many electrical grid transients can be described by the propagation of electromechanical (EM) waves that couple oscillations of power flows over transmission lines and the inertia of synchronous generators. These EM waves can take several forms: large-scale standing waves forming inter-area modes, localized oscillations of single or multi-machine modes, or traveling waves that spread quasi-circularly from major grid disturbances. The propagation speed and damping of these EM waves are potentially a powerful tool for assessing grid stability, e.g. small signal or rotor angle stability, however, EM wave properties have been mostly extracted from post-event analysis of major grid disturbances. Using a small set of data from the FNET sensor network, we show how the spatially resolved Green's function for EM wave propagation can be extracted from ambient frequency noise without the need for a major disturbance. If applied to an entire interconnection, an EM-wave Green's function map will enable a model-independent...

  19. Protective measurement of the wave function of a single squeezed harmonic-oscillator state Orly Alter and Yoshihisa Yamamoto

    E-print Network

    Utah, University of

    Protective measurement of the wave function of a single squeezed harmonic-oscillator state Orly measurement, therefore, allows for a definition of the quantum wave function on a single system. Yet, this equivalency also suggests that both measurement schemes account for the epistemological meaning of the wave

  20. Early heat waves over Italy and their impacts on durum wheat yields

    NASA Astrophysics Data System (ADS)

    Fontana, Giovanna; Toreti, Andrea

    2015-04-01

    In the last decades the Euro-Mediterranean region has experienced an increase in extreme temperature events such as warm spells and heat waves. These extreme weather conditions can strongly affect arable crop growth and final yields. Since the most sensitive period for winter wheat in the Italian Peninsula is May-June, early heat waves from 1985 to 2013 are here identified and characterised. Then, their impact on annual durum wheat yields from 1995 to 2013 is investigated by using durum wheat yield time series retrieved from the Italian National Institute of Statistics - ISTAT for the most important (in term of durum wheat production) 39 areas. Results confirm, as expected, the 2003 peak in the time series of heat wave intensities and highlight other significant events, for instance in 2006, 2007 and 2009. In 2003, the development and growth of durum wheat were greatly influenced by heat stress, as shown by the very low values of durum wheat yields, exceeding -52% in southern Italy. However, the negative peak of yield anomalies (-65%) is recorded in south-eastern Italy in 2009. Results also show a high percentage (w.r.t. the total number of years with significant negative yield anomaly) of concurrent early heat waves/significant negative yield anomaly in many of the investigated areas. In the other areas (e.g., Sicily), lower numbers of concurrent events could be caused by the late occurrence of the early heat waves, i.e., after durum wheat maturity.

  1. Impact of boat generated waves over an estuarine intertidal zone of the Seine estuary (France)

    NASA Astrophysics Data System (ADS)

    Deloffre, Julien; Lafite, Robert

    2015-04-01

    Water movements in macrotidal estuaries are controlled by the tidal regime modulated seasonally by the fluvial discharge. Wind effect on hydrodynamics and sediment transport is also reported at the mouth. Besides estuaries are frequently man altered our knowledge on the human impact on hydrodynamics and sediment transport is less extended. As an example on the Seine estuary (France) port authorities have put emphasis on facilitating economic exchanges by means of embankment building and increased dredging activity over the last century. These developments led to secure sea vessel traffic in the Seine estuary but they also resulted in a change of estuarine hydrodynamics and sediment transport features. Consequences of boat generated waves are varied: increased water turbidity and sediment transfer, release of nutrient and contaminants in the water column, harmful to users, ecosystems and infrastructures generating important maintenance spending. The aim of this study is to analyse the impact of boat generated waves on sediment transport over an intertidal area. The studied site is located on the left bank in the fluvial part of the Seine estuary. On this site the maximum tidal range ranges between 1.25 and 3.5m respectively during neap and spring tide. The sampling strategy is based on continuous ADV acquisition at 4Hz coupled with turbidimeter and altimeter measurements (1 measurement every minute) in order to decipher sediment dynamics during one year. Our results indicate that sediment dynamics are controlled by river flow while medium term scale evolution is dependent on tidal range and short term dynamics on sea-vessels waves. 64% of boat passages generated significant sediment reworking (from few mm.min-1 to 3cm.min-1). This reworking rate is mainly controlled by two parameters: (i) water height on the site and (ii) vessels characteristics; in particular the distance between seabed and keel that generate a Bernoulli wave (with maximum amplitude of 0.6m). Simultaneous hydrodynamics and bed elevation measurements permit to quantify the impact of the boat generated wave. Measurements demonstrate that the sediment transport occurs during the Bernoulli wave (few mm up to 8cm). This mechanism induces mainly a long-shore transfer of particles over the interdal area. This study proves that the sediment transport generated by boat waves cannot be neglected in the Seine estuary case.

  2. Using a coupled wave and ocean circulation modeling system to investigate the impacts of Hurricane Isabel

    NASA Astrophysics Data System (ADS)

    Armstrong, B. N.; Warner, J. C.; He, R.

    2008-12-01

    We use a coupled ocean - wave (ROMS - SWAN) modeling system to investigate the impacts of storms on coastal environments. The models were run for the period from September 5 - 25, 2003 to simulate ocean conditions during hurricane Isabel. The model domain covered part of the western North Atlantic, including the entire east coast of the United States and the Gulf of Mexico. Boundary conditions were obtained from global models. Wind forcing combined NARR (North American Regional Reanalysis) and HRD (NOAA Hurricane Research Division of AOML) gridded surface wind. SWAN and ROMS were each run separately and then run as a coupled system to assess changes in the model output resulting from the simulation of a realistic scenario through exchange of current and wave information. Outputs from these models were compared with measured wave height, salinity, sea surface temperature (SST), and current time series data to assess improvements in prediction resulting from using a coupled modeling system. Results from the uncoupled models demonstrated good agreement with wave and current data series. Results from the coupled system showed increased wave heights in regions of strong currents such as the Gulf Stream. Coupled model wave heights decreased in the open ocean preceding tropical storm Fabian and Hurricane Isabel but showed a large increase in inlets when Isabel made landfall. Depth- averaged velocities showed improvement in the coupled model. Sea surface temperatures in the wake of the hurricane were more realistic for the coupled simulation because the ocean model used the wave heights in the surface roughness computation and this created an increased surface mixing.

  3. Impact Of Coral Structures On Wave Directional Spreading Across A Shallow Reef Flat - Lizard Island, Northern Great Barrier Reef

    NASA Astrophysics Data System (ADS)

    Leon, J. X.; Baldock, T.; Callaghan, D. P.; Hoegh-guldberg, O.; Mumby, P.; Phinn, S. R.; Roelfsema, C. M.; Saunders, M. I.

    2013-12-01

    Coral reef hydrodynamics operate at several and overlapping spatial-temporal scales. Waves have the most important forcing function on shallow (< 5 m) reefs as they drive most ecological and biogeochemical processes by exerting direct physical stress, directly mixing water (temperature and nutrients) and transporting sediments, nutrients and plankton. Reef flats are very effective at dissipating wave energy and providing an important ecosystem service by protecting highly valued shorelines. The effectiveness of reef flats to dissipate wave energy is related to the extreme hydraulic roughness of the benthos and substrate composition. Hydraulic roughness is usually obtained empirically from frictional-dissipation calculations, as detailed field measurements of bottom roughness (e.g. chain-method or profile gauges) is a very labour and time-consuming task. In this study we measured the impact of coral structures on wave directional spreading. Field data was collected during October 2012 across a reef flat on Lizard Island, northern Great Barrier Reef. Wave surface levels were measured using an array of self-logging pressure sensors. A rapid in situ close-range photogrammetric method was used to create a high-resolution (0.5 cm) image mosaic and digital elevation model. Individual coral heads were extracted from these datasets using geo-morphometric and object-based image analysis techniques. Wave propagation was modelled using a modified version of the SWAN model which includes the measured coral structures in 2m by 1m cells across the reef. The approach followed a cylinder drag approach, neglecting skin friction and inertial components. Testing against field data included bed skin friction. Our results show, for the first time, how the variability of the reef benthos structures affects wave dissipation across a shallow reef flat. This has important implications globally for coral reefs, due to the large extent of their area occupied by reef flats, particularly, as global-scale degradation in coral reef health is causing a lowering of reef carbonate production that might lead to a decrease in reef structure and roughness.

  4. A spectral Phase-Amplitude method for propagating a wave function to large distances

    NASA Astrophysics Data System (ADS)

    Rawitscher, George

    2015-06-01

    The phase and amplitude (Ph-A) of a wave function vary slowly with distance, in contrast to the wave function that can be highly oscillatory. Hence the Ph-A representation of a wave function requires far fewer computational mesh points than the wave function itself. In 1930 Milne presented an equation for the phase and the amplitude functions (which is different from the one developed by Calogero), and in 1962 Seaton and Peach solved these equations iteratively. The objective of the present study is to implement Seaton and Peach's iteration procedure with a spectral Chebyshev expansion method, and at the same time present a non-iterative analytic solution to an approximate version of the iterative equations. The iterations converge rapidly for the case of attractive potentials. Two numerical examples are given: (1) for a potential that decreases with distance as 1 /r3, and (2) a Coulomb potential ? 1 / r. In both cases the whole radial range of [0-2000] requires only between 25 and 100 mesh points and the corresponding accuracy is between 10-3 and 10-6. The 0th iteration (which is the WKB approximation) gives an accuracy of 10-2. This spectral method permits one to calculate a wave function out to large distances reliably and economically.

  5. Completeness of the Coulomb Wave Functions in Quantum Mechanics

    ERIC Educational Resources Information Center

    Mukunda, N.

    1978-01-01

    Gives an explicit and elementary proof that the radial energy eigenfunctions for the hydrogen atom in quantum mechanics, bound and scattering states included, form a complete set. The proof uses some properties of the confluent hypergeometric functions and the Cauchy residue theorem from analytic function theory. (Author/GA)

  6. Shock-wave-induced fracturing of calcareous nannofossils from the Chesapeake Bay impact crater

    USGS Publications Warehouse

    Self-Trail J.M.

    2003-01-01

    Fractured calcareous nannofossils of the genus Discoaster from synimpact sediments within the Chesapeake Bay impact crater demonstrate that other petrographic shock indicators exist for the cratering process in addition to quartz minerals. Evidence for shock-induced taphonomy includes marginal fracturing of rosette-shaped Discoaster species into pentagonal shapes and pressure- and temperature-induced dissolution of ray tips and edges of discoasters. Rotational deformation of individual crystallites may be the mechanism that produces the fracture pattern. Shock-wave-fractured calcareous nannofossils were recovered from synimpact matrix material representing tsunami or resurge sedimentation that followed impact. Samples taken from cohesive clasts within the crater rubble show no evidence of shock-induced fracturing. The data presented here support growing evidence that microfossils can be used to determine the intensity and timing of wet-impact cratering.

  7. The Computation of Wave Functions in Momentum Space - II: The Hydrogen Molecule Ion

    Microsoft Academic Search

    R. McWeeny

    1949-01-01

    A new approach is made to the problem of computing accurate momentum distribution functions for electrons in molecules. The usual molecular orbital wave function (linear combination of atomic orbitals) has already been employed for this purpose but has proved inadequate in attempts to explain the width of the Compton profile. Using the method of a previous paper, the l.c.a.o. type

  8. THE EVANS FUNCTION AND STABILITY CRITERIA FOR DEGENERATE VISCOUS SHOCK WAVES

    E-print Network

    Howard, Peter

    in the general systems analyses of Gardner and Zumbrun [GZ], or Zumbrun and Howard [ZH], and that NishiharaTHE EVANS FUNCTION AND STABILITY CRITERIA FOR DEGENERATE VISCOUS SHOCK WAVES Peter Howard and Kevin of such operators was taken in the late eighties by Alexander, Gardner, and Jones, whose Evans function

  9. 2130 Learning Goals Draft 3: 12/8/06 1. wave function and probability

    E-print Network

    Colorado at Boulder, University of

    of matter. · Recognize that when things exist in certain energy states, they take on certain probability function description of matter replaces the particle description of matter. · Determine a potential energy · Recognize that matter is described by wave functions, not by particles moving along trajectories

  10. Direct Fragmentation of Quarkonia Including Fermi Motion Using Light-cone Wave Function

    E-print Network

    M. A. Gomshi Nobary; B. Javadi

    2006-06-12

    We investigate the effect of Fermi motion on the direct fragmentation of the $J/\\psi$ and $\\Upsilon$ states employing a light-cone wave function. Consistent with such a wave function we set up the kinematics of a heavy quark fragmenting into a quarkonia such that the Fermi motion of the constituents split into longitudinal as well as transverse direction and thus calculate the fragmentation functions for these states. In the framework of our investigation, we estimate that the fragmentation probabilities of $J/\\psi$ and $\\Upsilon$ may increase at least up to 14 percent when including this degree of freedom.

  11. Remarks on the Wave Function of the Universe in the Dilaton Cosmology

    E-print Network

    Wontae Kim; Edwin J. Son; Myung Seok Yoon

    2006-07-27

    Motivated by previous works, we study semi-classical cosmological solutions and the wave function of the Wheeler-DeWitt equation in the Bose-Parker-Peleg model. We obtain the wave function of the universe satisfying the suitable boundary condition of the redefined fields, which has not been considered in previous works. For some limiting cases, the Wheeler-DeWitt equation is reduced to the Liouville equation with a boundary, and its solution can be described by well-known functions. The consistent requirement of the boundary condition is related to the avoidance of the curvature singularity.

  12. Short-time-evolved wave functions for solving quantum many-body problems 

    E-print Network

    Ciftja, O.; Chin, Siu A.

    2003-01-01

    to a shadow wave function with an optimized Jastrow particle- particle pseudopotential ~OJ! and scaled Aziz HFDHE2 shadow-shadow pseudopotential ~AS!.24 GFMC is the Green?s-Function Monte Carlo calculations with Mcmillan form for importance... variational Monte Carlo calculation with the indi- cated wave function. All simulations use the Aziz HFDHE2 poten- tial and have been performed for systems of N5108 particles. The M1MS results are taken from Vitiello et al. ~Ref. 23!. The M 1AS and OJ...

  13. Transient difference solutions of the inhomogeneous wave equation: Simulation of the Green's function

    NASA Technical Reports Server (NTRS)

    Baumeiste, K. J.

    1983-01-01

    A time-dependent finite difference formulation to the inhomogeneous wave equation is derived for plane wave propagation with harmonic noise sources. The difference equation and boundary conditions are developed along with the techniques to simulate the Dirac delta function associated with a concentrated noise source. Example calculations are presented for the Green's function and distributed noise sources. For the example considered, the desired Fourier transformed acoustic pressures are determined from the transient pressures by use of a ramping function and an integration technique, both of which eliminates the nonharmonic pressure associated with the initial transient.

  14. Basis of symmetric polynomials for many-boson light-front wave functions.

    PubMed

    Chabysheva, Sophia S; Hiller, John R

    2014-12-01

    We provide an algorithm for the construction of orthonormal multivariate polynomials that are symmetric with respect to the interchange of any two coordinates on the unit hypercube and are constrained to the hyperplane where the sum of the coordinates is one. These polynomials form a basis for the expansion of bosonic light-front momentum-space wave functions, as functions of longitudinal momentum, where momentum conservation guarantees that the fractions are on the interval [0,1] and sum to one. This generalizes earlier work on three-boson wave functions to wave functions for arbitrarily many identical bosons. A simple application in two-dimensional ?(4) theory illustrates the use of these polynomials. PMID:25615225

  15. Wave Functions for Quantum Black Hole Formation in Scalar Field Collapse

    E-print Network

    Dongsu Bak; Sang Pyo Kim; Sung Ku Kim; Kwang-Sup Soh; Jae Hyung Yee

    1999-10-05

    We study quantum mechanically the self-similar black hole formation by collapsing scalar field and find the wave functions that give the correct semiclassical limit. In contrast to classical theory, the wave functions for the black hole formation even in the supercritical case have not only incoming flux but also outgoing flux. From this result we compute the rate for the black hole formation. In the subcritical case our result agrees with the semiclassical tunneling rate. Furthermore, we show how to recover the classical evolution of black hole formation from the wave function by defining the Hamilton-Jacobi characteristic function as $W = \\hbar {\\rm Im} \\ln \\psi$. We find that the quantum corrected apparent horizon deviates from the classical value only slightly without any qualitative change even in the critical case.

  16. Microscopic electronic wave function and interactions between quasiparticles in empirical tight-binding theory

    NASA Astrophysics Data System (ADS)

    Benchamekh, R.; Raouafi, F.; Even, J.; Ben Cheikh Larbi, F.; Voisin, P.; Jancu, J.-M.

    2015-01-01

    A procedure to obtain single-electron wave functions within the tight-binding formalism is proposed. It is based on linear combinations of Slater-type orbitals whose screening coefficients are extracted from the optical matrix elements of the tight-binding Hamiltonian. Bloch functions obtained for zinc-blende semiconductors in the extended-basis s p d s* tight-binding model demonstrate very good agreement with first-principles wave functions. We apply this method to the calculation of the electron-hole exchange interaction, and obtain the dispersion of excitonic fine structure in bulk GaAs. Beyond semiconductor nanostructures, this work is a fundamental step toward modeling many-body effects from post-processing single-particle wave functions within the tight-binding theory.

  17. Shoreline changes and high-energy wave impacts at the leeward coast of Bonaire (Netherlands Antilles)

    NASA Astrophysics Data System (ADS)

    Engel, Max; Brückner, Helmut; Messenzehl, Karoline; Frenzel, Peter; May, Simon Matthias; Scheffers, Anja; Scheffers, Sander; Wennrich, Volker; Kelletat, Dieter

    2012-10-01

    Supralittoral coarse-clast deposits along the shores of Bonaire (Netherlands Antilles) as well as increased hurricane frequency during the past decade testify to the major hazard of high-energy wave impacts in the southern Caribbean. Since deducing certain events from the subaerial coarse-clast record involves major uncertainties and historical reports are restricted to the past 500 years, we use a new set of vibracore and push core data (i) to contribute to a more reliable Holocene history of regional extreme-wave events and (ii) to evaluate their impact on shoreline evolution. Multi-proxy palaeoenvironmental analyses (XRF, XRD, grain size distribution, carbonate, LOI, microfossils) were carried out using nearshore sedimentary archives from the sheltered western (leeward) side of Bonaire and its small neighbour Klein Bonaire. In combination with 14C-AMS age estimates the stratigraphy reflects a long-term coastal evolution controlled by relative sea level rise, longshore sediment transport, and short-term morphodynamic impulses by extreme wave action, all three of which may have significantly influenced the development of polyhaline lagoons and the demise of mangrove populations. Extreme wave events may be categorized into major episodic incidents (c. 3.6 ka [?] BP; 3.2-3.0 ka BP; 2.0-1.8 ka BP; post-1.3 ka [?] BP), which may correspond to tsunamis and periodic events recurring on the order of decades to centuries, which we interpret as severe tropical cyclones. Extreme wave events seem to control to a certain extent the formation of coastal ridges on Bonaire and, thus, to cause abrupt shifts in the long-term morphodynamic and ecological boundary conditions of the circumlittoral inland bays.

  18. Clinical application of plasma shock wave lithotripsy in treating impacted stones in the bile duct system

    PubMed Central

    Xu, Zhi; Wang, Li-Xin; Zhang, Neng-Wei; Hou, Chun-Sheng; Ling, Xiao-Feng; Xu, Yao; Zhou, Xiao-Si

    2006-01-01

    AIM: To verify the safety and efficacy of plasma shock wave lithotripsy (PSWL) in fragmenting impacted stones in the bile duct system. METHODS: From September 1988 to April 2005, 67 patients (26 men and 41 women) with impacted stones underwent various biliary operations with tube (or T-tube) drainage. Remnant and impacted stones in the bile duct system found by cholangiography after the operation were fragmented by PSWL and choledochofiberscopy. A total of 201 impacted stones were fragmented by PSWL setting the voltage at 2.5-3.5 kV, and the energy output at 2-3 J for each pulse of PSWL. Then the fragmented stones were extracted by choledochofiberscopy. The safety and efficacy of PSWL were observed during and after the procedure. RESULTS: One hundred and ninety-nine of 201 impacted stones (99.0%) in the bile duct system were successfully fragmented using PSWL and extracted by choledochofiberscopy. The stone clearance rate for patients was 97% (65/67). Ten patients felt mild pain in the right upper quadrant of the abdomen, and could tolerate it well. Eleven patients had a small amount of bleeding from the mucosa of the bile duct. The bleeding was transient and stopped spontaneously within 2 min of normal saline irrigation. There were no significant complications during and after the procedure. CONCLUSION:PSWL is a safe and effective method for fragmenting impacted stones in the bile duct system. PMID:16440432

  19. The impact of alcohol dependence on social brain function.

    PubMed

    Gizewski, Elke R; Müller, Bernhard W; Scherbaum, Norbert; Lieb, Bodo; Forsting, Michael; Wiltfang, Jens; Leygraf, Norbert; Schiffer, Boris

    2013-01-01

    The impact of alcoholism (ALC) or alcohol dependence on the neural mechanisms underlying cognitive and affective empathy (i.e. the different routes to understanding other people's minds) in schizophrenic patients and non-schizophrenic subjects is still poorly understood. We therefore aimed at determining the extent to which the ability to infer other people's mental states and underlying neural mechanisms were affected by ALC. We examined 48 men, who suffered either from ALC, schizophrenia, both disorders or none of these disorders, using functional magnetic resonance imaging while performing on a mind reading task that involves both cognitive and affective aspects of empathy. Using voxel-based morphometry, we additionally examined whether between-group differences in functional activity were associated with deficits in brain structural integrity. During mental state attribution, all clinical groups as compared with healthy controls exhibited poor performance as well as reduced right-hemispheric insular function with the highest error rate and insular dysfunction seen in the schizophrenic patients without ALC. Accordingly, both behavioral performance and insular functioning revealed schizophrenia × ALC interaction effects. In addition, schizophrenic patients relative to non-schizophrenic subjects (regardless of ALC) exhibited deficits in structural integrity and task-related recruitment of the left ventrolateral prefrontal cortex (vlPFC). Our data suggest that ALC-related impairment in the ability to infer other people's mental states is limited to insular dysfunction and thus deficits in affective empathy. By contrast, mentalizing in schizophrenia (regardless of ALC) may be associated with insular dysfunction as well as a combination of structural and functional deficits in the left vlPFC. PMID:22340281

  20. Mathieu function solutions for photoacoustic waves in sinusoidal one-dimensional structures

    NASA Astrophysics Data System (ADS)

    Wu, Binbin; Diebold, Gerald J.

    2012-07-01

    The photoacoustic effect for a one-dimensional structure, the sound speed of which varies sinusoidally in space, is shown to be governed by an inhomogeneous Mathieu equation with the forcing term dependent on the spatial and temporal properties of the exciting optical radiation. New orthogonality relations, traveling wave Mathieu functions, and solutions to the inhomogeneous Mathieu equation are found, which are used to determine the character of photoacoustic waves in infinite and finite length phononic structures. Floquet solutions to the Mathieu equation give the positions of the band gaps, the damping of the acoustic waves within the band gaps, and the dispersion relation for photoacoustic waves. The solutions to the Mathieu equation give the photoacoustic response of the structure, show the space equivalent of subharmonic generation and acoustic confinement when waves are excited within band gaps.

  1. Gutzwiller correlated wave functions in finite dimensions d: A systematic expansion in 1/d

    NASA Astrophysics Data System (ADS)

    Gebhard, Florian

    1990-05-01

    We present a systematic formalism for the variational evaluation of ground-state properties of Hubbard-type models in finite dimensions d. The formalism starts from generalized Gutzwiller correlated wave functions, which are then studied in a systematic (1/d) expansion around the limit of high dimensions (d=?). The limit of d-->? has recently been introduced by Metzner and Vollhardt (MV) for itinerant lattice fermion systems. The approach, presented in this paper, is particularly efficient since results in d=? are obtained without having to calculate a single graph. Our results confirm the finding of MV that counting approximations in the spirit of the Gutzwiller approximation become exact in d=? for translationally invariant wave functions. This type of approximation is no longer exact for more complicated (e.g., antiferromagnetic) wave functions. In addition, we completely reproduce the results of the Kotliar-Ruckenstein path-integral approach to the Hubbard model. Performing a (1/d) expansion for the Gutzwiller wave function, we show that the lowest orders in (1/d) are sufficient to reproduce all numerical findings in d=2,3 quantitatively. We therefore conclude that the limit of d=? is a very fruitful starting point for the study of finite-dimensional systems. On the basis of our study we propose new variational wave functions for the numerical investigation of antiferromagnetism in the Hubbard, the t-J, and the spin-1/2 Heisenberg model. For the first two models we calculate in d=? only, for the Heisenberg model we also derive corrections up to order (1/d). To this order we obtain complete agreement with linear spin-wave theory. Since our trial state is based on a fermionic description of the Heisenberg model, we interpret this analytically determined wave function as Fermi sea of spin-1/2 quasiparticles (``spinons'').

  2. Nonanalyticity of the Electron Distribution Function and Nonlinear Electromagnetic Waves in Semiconductors

    NASA Astrophysics Data System (ADS)

    Rozhkov, Sergei S.

    2000-03-01

    Nonanalyticity of the Electron Distribution Function and Nonlinear Electromagnetic Waves in Semiconductors S.S.Rozhkov Institute of Physics, Ukrainian Academy of Sciences, Kyiv, Ukraine It is shown that propagation of electromagnetic waves in a plasma is nonlinear if the charge carrier distribution function has fractures or, more exactly, nonanalyticies. This result is valid for any plasma. In the case under consideration the nature of the nonanalyticities is connected with spontaneous optical-phonon emission by the nonequilibrium electrons of a semiconductor. The standard wave equation for the electromagnetic field E in a plasma implies that the formula dJ/dt = (?o ?_p^2/4?)E for the current density J takes place (eo is the static dielectric constant and wp is the plasma frequency). If the distribution function f(p) is nonanalytical on some set of points of momentum space, then the ordinary formula connecting J and E is violated, and the wave equation becomes nonlinear. In the high-frequency limit we find the function f(p) and derive the wave equation for E in a semiconductor placed in parallel constant electric and quantizing magnetic fields. In such a situation the stationary electron distribution function acquires sharply expressed fractures as a result of runaway of the electrons and spontaneous optical-phonon emission hindering the runaway. Creation and dynamics of dark envelope solitons for the field E are discussed footnote S.S.Rozhkov, JETP 71, 1135 (1990).

  3. Off-shell photon light-cone wave functions with odd chirality

    NASA Astrophysics Data System (ADS)

    Yu, Ran; Liu, Jueping; Zhu, Kai

    2006-06-01

    Based on a more reasonable simulation method for dealing with the ?-parameter characterizing the pole form for the form factor (the Fourier transform of the instanton zero mode), and a unified way for regularizing the integrals appearing in the expressions of the light-cone photon wave functions, the transverse photon wave function ?_{{?perp}}^{}(u, P 2) at the leading twist with the on-shell or off-shell momentum have been re-examined in the effective low-energy theory derived from the instanton vacuum, and the twist-two parts of the other two photon wave functions, h (s), twisttwo ? || (u, P 2) and h (t), twisttwo ? || (u, P 2), with odd chirality are calculated based on the Wandzura-Wilczek-like relations as well. A brief discussion of the dependence of the coupling f ? ?(P 2) and the light-cone photon wave functions with respect to P2 and the end-point behavior of the photon wave functions are given.

  4. Quantum field theory solves the problem of the collapse of the wave function

    E-print Network

    Alexey V. Melkikh

    2013-11-01

    The problem of measurement in quantum mechanics is that the quantum particle in the course of evolution, as described by the linear Schrodinger equation, exists in all of its possible states, but in measuring, the particle is always detected in only one of its states. This property is called the "collapse of the wave function" and was formulated by Von Neumann as one of the postulates of quantum mechanics. However, it remains unclear at what point in time and under what laws this transition occurs. This article demonstrates that the collapse of the wave function may be due to the creation or annihilation of particles (quasi-particles). The processes of the creation or annihilation of particles play a key role in the measurements and are described on the basis of quantum field theory. The system of equations of quantum field theory of particles and fields is non-linear; as a result, the principle of superposition does not hold for the theory. The collapse of the wave function is a consequence of this non-linearity and occurs at the moment of creation (annihilation) of a particle. This result demonstrates that the wave function collapse can occur in both microscopic and macroscopic systems. Understanding the mechanisms of the collapse of the wave function can lead to the creation of microscopic devices involved in the calculations based on quantum computing.

  5. Impacts of updated green vegetation fraction data on WRF simulations of the 2006 European heat wave

    NASA Astrophysics Data System (ADS)

    Refslund, J.; Dellwik, E.; Hahmann, A. N.; Barlage, M. J.; Boegh, E.

    2012-12-01

    Climate change studies suggest an increase in heat wave occurrences over Europe in the coming decades. Extreme events with excessive heat and associated drought will impact vegetation growth and health and lead to alterations in the partitioning of the surface energy. In this study, the atmospheric conditions during the heat wave year 2006 over Europe were simulated using the Weather Research and Forecasting (WRF) model. To account for the drought effects on the vegetation, new high-resolution green vegetation fraction (GVF) data were developed for the domain using NDVI data from MODIS satellite observations. Many empirical relationships exist to convert NDVI to GVF and both a linear and a quadratic formulation were evaluated. The new GVF product has a spatial resolution of 1 km2 and a temporal resolution of 8 days. To minimize impacts from low-quality satellite retrievals in the NDVI series, as well as for comparison with the default GVF climatology in WRF, a new background climatology using 10 recent years of observations was also developed. The annual time series of the new GVF climatology was compared to the default WRF GVF climatology at 18 km2 grid resolution for the most common land use classes in the European domain. The new climatology generally has higher GVF levels throughout the year, in particular an extended autumnal growth season. Comparison of 2006 GVF with the climatology clearly indicates vegetation stresses related to heat and drought. The GVF product based on a quadratic NDVI relationship shows the best agreement with the magnitude and annual range of the default input data, in addition to including updated seasonality for various land use classes. The new GVF products were tested in WRF and found to work well for the spring of 2006 where the difference between the default and new GVF products was small. The WRF 2006 heat wave simulations were verified by comparison with daily gridded observations of mean, minimum and maximum temperature and daily precipitation. The simulation using the new GVF product with a quadratic relationship to NDVI resulted in a consistent improvement of modeled temperatures during the heat wave period, where the mean temperature cold bias of the model was reduced by 10% for the whole domain and by 30-50% in areas severely affected by the heat wave. More improvement was found in the simulation of minimum temperature and less in maximum temperature and the impact on precipitation was not significant. The results show that model simulations during heat waves and droughts, when vegetation condition deviates from climatology, require updated land surface properties in order to obtain reliably accurate results.

  6. Fracture of Coarse-Grained and Ultrafine-Grained Titanium Upon Quasi-Static and Wave-Impact Loading

    NASA Astrophysics Data System (ADS)

    Dudarev, E. F.; Afanasyeva, S. A.; Bakach, G. P.; Belov, N. N.; Markov, A. B.; Tabachenko, A. N.; Habibullin, M. V.; Yugov, N. T.; Maletkina, T. Yu.

    2015-03-01

    Results of experimental investigation of the regularities and mechanisms of fracture of coarse-grained and ultrafine-grained titanium upon wave-impact loading, exposure to a nanosecond relativistic high-current electron beam, and quasi-static tension are presented. Results of computer modeling of the shock wave generated upon exposure to the electron beam and of the spalling fracture of titanium targets with coarsegrained and ultrafine-grained structures are presented. The general regularities and special features of fracture are established for both grained structures under quasi-static and wave-impact loading.

  7. Kinetic correlation in the final-state wave function in photo-double-ionization of He

    SciTech Connect

    Otranto, S. [CONICET and Centro Atomico Bariloche, 8400 San Carlos de Bariloche, (Argentina); Departamento de Fisica, Universidad Nacional del Sur, 8000 Bahia Blanca, (Argentina); Garibotti, C. R. [CONICET and Centro Atomico Bariloche, 8400 San Carlos de Bariloche, (Argentina)

    2003-06-01

    We evaluate the triply differential cross section (TDCS) for photo-double-ionization of helium. We use a final continuum wave function which correlates the motion of the three particles, through an expansion in products of two-body Coulomb functions. This function satisfies a set of appropriate physical conditions in the coalescence points, in addition to the correct asymptotic behavior condition. We analyze the effect of this correlation in the TDCS and compare our results with experimental data.

  8. In vivo transmission of impact shock waves in the distal forelimb of the horse.

    PubMed

    Gustås, P; Johnston, C; Roepstorff, L; Drevemo, S

    2001-04-01

    There is a high prevalence of lameness among Standardbred trotters, most commonly caused by noninfectious joint diseases, mainly related to training and competition. In this context, impact-related shock waves transmitted through the skeleton and joints have been proposed to be one important factor in the development of osteoarthritis. The aim of the present study was to investigate the characteristic pattern of the events immediately following first contact, with a focus on the in vivo transmission of impact shock waves in the distal forelimb. Two horses were trotted by hand over a force plate. Recordings of 3-D kinematics of the distal forelimb were carried out by use of a 240 Hz video system. Tri-axial accelerometer data were collected from a bone-mounted accelerometer on the midlateral side of the third metacarpal bone (McIII) and from another accelerometer attached to the lateral side of the hoof. Force plate and accelerometer data were sampled at 4.8 kHz using a 16-bit A/D-converter, synchronised with the kinematic data. The results indicate that the time lapse of the horizontal retardation of the hoof is an important factor in the attenuation of the impact. A shorter period of hoof braking showed higher amplitudes in the longitudinal retardation of McIII and a more rapid oscillation. This makes all parameters that affect the horizontal hoof braking potentially important to the orthopaedic health of the horse. PMID:11721549

  9. Interpreting scattering wave functions in the presence of energy-dependent interactions

    E-print Network

    Scott Pratt

    2007-11-09

    In scattering theory, the squared relative wave function $|\\phi({\\bf q},{\\bf r})|^2$ is often interpreted as a weight, due to final-state interactions, describing the probability enhancement for emission with asymptotic relative momentum $q$. An equivalence relation also links the integral of the squared wave function over all coordinate space to the density of states. This relation, which plays an important role in understanding two-particle correlation phenomenology, is altered for the case where the potential is energy dependent, as is assumed in various forms of reaction theory. Here, the modification to the equivalence relation is derived, and it is shown that the squared wave function should be augmented by a additional factor if it is to represent the emission enhancement for final-state interactions. Examples with relativistic vector interactions, e.g., the Coulomb interaction, are presented.

  10. Off-Shell Photon Longitudinal Light-Cone Wave Function at Leading Twist

    NASA Astrophysics Data System (ADS)

    Zhu, Kai; Liu, Jueping; Yu, Ran

    The leading twist longitudinal virtual photon light-cone wave function, ???(u, P2), is calculated within the framework of the low-energy effective theory arising from the instanton model of QCD vacuum. Corresponding to the non-perturbative effects at low-energy scale, a suitable regularization scale T is fixed by analysing the differential behavior of the photon wave function on the internal transverse momentum cut-off in the light-cone frame. The coupling constant, F?(P2), of the quark-antiquark vector current to the virtual photon state is also obtained by imposing the normalization condition. The feature of the obtained photon wave function has been discussed at the end as well as the coupling constant.

  11. Exact wave functions of bound ?- for calculating ordinary muon capture rates

    NASA Astrophysics Data System (ADS)

    Kardaras, I. S.; Stavrou, V. N.; Tsoulos, I. G.; Kosmas, T. S.

    2013-02-01

    The goal of the present contribution is twofold: (i) To compute exact wave functions for a muon bound in the extended Coulomb potential of a muonic atom by solving the Dirac equation within the context of genetic algorithms and neural network techniques using experimental finite-size charge-densities for the attracting nucleus. (ii) To calculate partial and total rates of the ordinary muon capture in various muonic atoms. In contrast to the majority of previous realistic calculations for ?--capture rates, in our present work we utilize the above mentioned exact wave functions for a muon orbiting at the Is and 2p atomic orbits. The required many-body nuclear wave functions are obtained by diagonalizing the eigenvalue problem of the quasi-particle random phase approximation (QRPA).

  12. Two Wave Functions and dS/CFT on S^1 x S^2

    E-print Network

    Gabriele Conti; Thomas Hertog

    2015-06-26

    We evaluate the tunneling and Hartle-Hawking wave functions on S^1 x S^2 boundaries in Einstein gravity with a positive cosmological constant. In the large overall volume limit the classical predictions of both wave functions include an ensemble of Schwarzschild-de Sitter black holes. We show that the Hartle-Hawking tree level measure on the classical ensemble converges in the small S^1 limit. A divergence in this regime can be identified in the tunneling state. However we trace this to the contribution of an unphysical branch of saddle points associated with negative mass black holes. Using a representation in which all saddle points have an interior Euclidean anti-de Sitter region we also generalise the holographic formulation of the semiclassical Hartle-Hawking wave function to S^1 x S^2 boundaries.

  13. Complex Energy of Harmonic Oscillator under Non-Hermitian transformation of momentum with real wave function

    E-print Network

    Biswanath Rath

    2015-05-19

    For the first time in the literature of Quantum Physics, we present complex energy eigenvalues of non-Hermitian Harmonic Oscillator $H=\\frac{(p+iLx)}^{2}}{2} + W^{2} \\frac{x^{2}}{2}$ with real wave function having positive frequency of vibration $(w)$ under some selective choice of $L$ and $W$ .Interestingly for the same values of $L$ and $W$, if the frequency of vibration $w$ in the real wave function is (some how) related as $w=L\\pmW$ or $w=W-L$ then the same oscillator can reflect either pure positive or negative energy eigenvalues.The real energy levels are in conformity with the perturbative calculation. PACS :03.65.Db;11.39.Er. Key words: Positive frequency, real wave function, complex energy, real positive energy,negative energy.

  14. Dissipation of Magnetohydrodynamic Waves on Energetic Particles: Impact on Interstellar Turbulence and Cosmic Ray Transport

    SciTech Connect

    Ptuskin, V.S.; /Troitsk, IZMIRAN /Maryland U.; Moskalenko, Igor V.; /Stanford U., HEPL; Jones, F.C.; /NASA, Goddard; Strong, A.W.; /Garching, Max Planck Inst., MPE; Zirakashvili, V.N.; /Troitsk, IZMIRAN /Heidelberg, Max Planck Inst. Astron.

    2006-01-17

    The physical processes involved in diffusion of Galactic cosmic rays in the interstellar medium are addressed. We study the possibility that the nonlinear MHD cascade sets the power-law spectrum of turbulence which scatters charged energetic particles. We find that the dissipation of waves due to the resonant interaction with cosmic ray particles may terminate the Kraichnan-type cascade below wavelengths 10{sup 13} cm. The effect of this wave dissipation has been incorporated in the GALPROP numerical propagation code in order to asses the impact on measurable astrophysical data. The energy-dependence of the cosmic-ray diffusion coefficient found in the resulting self-consistent model may explain the peaks in the secondary to primary nuclei ratios observed at about 1 GeV/nucleon.

  15. Dissipation of Magnetohydrodynamic Waves on Energetic Particles: Impact on Interstellar Turbulence and Cosmic Ray Transport

    E-print Network

    V. S. Ptuskin; I. V. Moskalenko; F. C. Jones; A. W. Strong; V. N. Zirakashvili

    2006-01-21

    The physical processes involved in diffusion of Galactic cosmic rays in the interstellar medium are addressed. We study the possibility that the nonlinear MHD cascade sets the power-law spectrum of turbulence which scatters charged energetic particles. We find that the dissipation of waves due to the resonant interaction with cosmic ray particles may terminate the Kraichnan-type cascade below wavelengths 10^13 cm. The effect of this wave dissipation has been incorporated in the GALPROP numerical propagation code in order to asses the impact on measurable astrophysical data. The energy-dependence of the cosmic-ray diffusion coefficient found in the resulting self-consistent model may explain the peaks in the secondary to primary nuclei ratios observed at about 1 GeV/nucleon.

  16. An European historical reconstruction of sea surface dynamics (waves and storm surge) for coastal impact studies

    NASA Astrophysics Data System (ADS)

    Menendez, Melisa; Perez, Jorge; Cid, Alba; Castanedo, Sonia; Losada, Inigo; Medina, Raul; Mendez, Fernando

    2015-04-01

    Despite their outstanding relevance in coastal processes, a study of the sea surface dynamics due to atmospheric wind and pressure variations are rather limited in comparison with the mean sea level rise. Data of waves and surges along the European region are scarce and in-homogeneous, not only in terms of spatial coverage but also in terms of temporal coverage. This study presents two databases focused on a historical reconstruction of: (i) the wind-generated waves (GOW) and (ii) the meteorological sea level component (GOS). The GOW and GOS datasets cover the whole European coast (North Atlantic, North Sea, Baltic Sea, Mediterranean Sea and Black Sea) at high-spatial resolution from 1979 to present. The meteorological sea level component (storm surge) has been generated by the Regional Ocean Model System (ROMS). To take into account non-linear interactions between tides and surges, both dynamics were simulated jointly. Final results of meteorological component of sea level were obtained by subtracting the astronomical tide from the simulated sea surface. The model was set-up for Europe using an orthogonal grid, with a horizontal resolution ranging between 3.5 to 11 km. A spatial domain of approximately 5 km was used for the Black Sea. Local coastal waves can be the integrated result of the ocean surface over a large region of influence. GOW-Europe is designed from a multigrid approach based on the overlapping of two-way nested domains. The coarser spatial resolution along the European coast of GOW is 15 km. The generation and propagation of the sea surface waves of GOW-Europe are simulated with the model WAVEWATCH III v4.18. Effects of non-linear wave-wave interactions, whitecapping and depth-induced refraction are considered in the propagation model. In order to validate GOW and GOS over Europe with available observations, an exhaustive comparison with in-situ and remote measurements was developed. In-situ buoys and tide-gauges are used to compare hourly time series of surge sea level component and waves (significant wave height, period and direction) at coastal locations. Altimeter observations are also considered for a spatial validation of surge and wave heights. Results obtained from this validation process show a general good agreement with observations for the European region. Finally, the hourly time series of surge and wave climate along the European coast grid-points are analyzed. Historical changes in the waves and storm surge provide a useful information for coastal impact studies since coastal flooding, beach erosion, coastal structures and physical damages in ecosystems can be affected by long-term changes in wave climate and sea levels. Reguero, B. G., Menéndez, M., Méndez, F. J. Mínguez, R. Losada, I. J. (2012). A Global Ocean Wave (GOW) calibrated reanalysis from 1948 onwards. Coastal Engineering, 65, 38-55. Cid, A., Castanedo, S., Abascal, A. J., Menéndez, M., & Medina, R. (2014). A high resolution hindcast of the meteorological sea level component for Southern Europe: the GOS dataset. Climate Dynamics, 1-18.

  17. The Impact of Chromospheric Activity on Observed Initial Mass Functions

    NASA Astrophysics Data System (ADS)

    Stassun, Keivan G.; Scholz, Aleks; Dupuy, Trent J.; Kratter, Kaitlin M.

    2014-12-01

    Using recently established empirical calibrations for the impact of chromospheric activity on the radii, effective temperatures, and estimated masses of active low-mass stars and brown dwarfs, we reassess the shape of the initial mass function (IMF) across the stellar/substellar boundary in the Upper Sco star-forming region (age ~ 5-10 Myr). We adjust the observed effective temperatures to warmer values using the observed strength of the chromospheric H? emission, and redetermine the estimated masses of objects using pre-main-sequence evolutionary tracks in the H-R diagram. The effect of the activity-adjusted temperatures is to shift the objects to higher masses by 3%-100%. While the slope of the resulting IMF at substellar masses is not strongly changed, the peak of the IMF does shift from ?0.06 to ?0.11 M ?. Moreover, for objects with masses <~ 0.2 M ?, the ratio of brown dwarfs to stars changes from ~80% to ~33%. These results suggest that activity corrections are essential for studies of the substellar mass function, if the masses are estimated from spectral types or from effective temperatures.

  18. Automatic determination of important mode-mode correlations in many-mode vibrational wave functions

    NASA Astrophysics Data System (ADS)

    König, Carolin; Christiansen, Ove

    2015-04-01

    We introduce new automatic procedures for parameterizing vibrational coupled cluster (VCC) and vibrational configuration interaction wave functions. Importance measures for individual mode combinations in the wave function are derived based on upper bounds to Hamiltonian matrix elements and/or the size of perturbative corrections derived in the framework of VCC. With a threshold, this enables an automatic, system-adapted way of choosing which mode-mode correlations are explicitly parameterized in the many-mode wave function. The effect of different importance measures and thresholds is investigated for zero-point energies and infrared spectra for formaldehyde and furan. Furthermore, the direct link between important mode-mode correlations and coordinates is illustrated employing water clusters as examples: Using optimized coordinates, a larger number of mode combinations can be neglected in the correlated many-mode vibrational wave function than with normal coordinates for the same accuracy. Moreover, the fraction of important mode-mode correlations compared to the total number of correlations decreases with system size. This underlines the potential gain in efficiency when using optimized coordinates in combination with a flexible scheme for choosing the mode-mode correlations included in the parameterization of the correlated many-mode vibrational wave function. All in all, it is found that the introduced schemes for parameterizing correlated many-mode vibrational wave functions lead to at least as systematic and accurate calculations as those using more standard and straightforward excitation level definitions. This new way of defining approximate calculations offers potential for future calculations on larger systems.

  19. Automatic determination of important mode-mode correlations in many-mode vibrational wave functions.

    PubMed

    König, Carolin; Christiansen, Ove

    2015-04-14

    We introduce new automatic procedures for parameterizing vibrational coupled cluster (VCC) and vibrational configuration interaction wave functions. Importance measures for individual mode combinations in the wave function are derived based on upper bounds to Hamiltonian matrix elements and/or the size of perturbative corrections derived in the framework of VCC. With a threshold, this enables an automatic, system-adapted way of choosing which mode-mode correlations are explicitly parameterized in the many-mode wave function. The effect of different importance measures and thresholds is investigated for zero-point energies and infrared spectra for formaldehyde and furan. Furthermore, the direct link between important mode-mode correlations and coordinates is illustrated employing water clusters as examples: Using optimized coordinates, a larger number of mode combinations can be neglected in the correlated many-mode vibrational wave function than with normal coordinates for the same accuracy. Moreover, the fraction of important mode-mode correlations compared to the total number of correlations decreases with system size. This underlines the potential gain in efficiency when using optimized coordinates in combination with a flexible scheme for choosing the mode-mode correlations included in the parameterization of the correlated many-mode vibrational wave function. All in all, it is found that the introduced schemes for parameterizing correlated many-mode vibrational wave functions lead to at least as systematic and accurate calculations as those using more standard and straightforward excitation level definitions. This new way of defining approximate calculations offers potential for future calculations on larger systems. PMID:25877570

  20. Factors Influencing the Shape of the Fracture Wave Induced by the Rod Impact of a Brittle Material

    NASA Astrophysics Data System (ADS)

    Resnyansky, A. D.; Bourne, N. K.

    2002-07-01

    A fracture wave in a brittle material is a continuous fracture zone which may be associated with the damage accumulation process during the propagation of shock waves. In multidimensional structures the fracture wave may behave in an unusual way. The high-speed photography of penetration of a borosilicate (pyrex) glass block by a hemispherical-nosed rod (1) shows a visible flat wave forming as the fracture front. The role of the complex stress state and kinetic description of the damage accumulation are analysed to describe the process of the impact. The DYNA2D hydrocode and a kinetic strain-rate sensitive model (2) are employed.

  1. The Impact of Heat Islands on Mortality in Paris during the August 2003 Heat Wave

    PubMed Central

    Zeghnoun, Abdelkrim; Dousset, Bénédicte; Bretin, Philippe; Vandentorren, Stéphanie; Giraudet, Emmanuel; Beaudeau, Pascal

    2011-01-01

    Background: Heat waves have a drastic impact on urban populations, which could increase with climate change. Objectives: We evaluated new indicators of elderly people’s exposure to heat in Paris, from a public health prevention perspective, using satellite thermal images. Methods: We used a time series of 61 images from the satellites of the National Oceanic and Atmospheric Administration’s (NOAA) Advanced Very High Resolution Radiometer (AVHRR) taken from 1 to 13 August 2003 to produce thermal indicators of minimum, maximum, and mean surface temperatures and diurnal temperature amplitude, with different lags between the meteorological data and the health impact. Health data came from a case–control study involving 241 people ? 65 years of age who died in the city of Paris or the nearby suburban area of Val-de-Marne during the August 2003 heat wave, and 241 controls who were matched to cases on age, sex, and residential zone. For each person, we integrated the thermal indicators in a conditional logistic regression model, adjusted for age and other potential confounders. We computed odds ratios (ORs) comparing the 90th and 50th percentiles of the temperature differences between cases and controls for various indicators. Results: Mortality risk was significantly associated with exposure for two indicators: minimum temperatures averaged for 1–13 August [for a 0.41°C increase, OR = 2.17; 95% confidence interval (CI): 1.14, 4.16] and minimum temperature averaged on the day of death and the 6 preceding days (for a 0.51°C increase: OR = 2.24; 95% CI: 1.03, 4.87). Conclusions: Our results support the influence of night temperatures on the health impact of heat waves in urban areas. Urban heat exposure indicators based on satellite imagery have the potential to identify areas with higher risk of death, which could inform intervention decisions by key stakeholders. PMID:21885383

  2. Coherent State Wave-Functions on a Torus with a Constant Magnetic Field

    NASA Astrophysics Data System (ADS)

    Fremling, Mikael

    2013-03-01

    We study two alternative definitions of localized states in the lowest Landau level (LLL) on a torus. The first is to project a delta function onto the LLL, while the other is to put all the N zeros of the wave function at the same point, thus localizing the function at the vicinity of the antipodal point. These two families of localized states both have many properties in common with the coherent states on the plane and on the sphere, viz. a simple resolution of unity and a self-reproducing kernel. However, only the projected delta function gives maximally localized states. We also show how to project expressions containing holomorphic derivatives and nonholomorphic coordinates onto the LLL, and briefly discuss the importance of this for constructing hierarchical QH wave functions.

  3. Wave-Functions for Spin3\\/2 and Integer Spin Fields

    Microsoft Academic Search

    Elsa Arcaute; Anthony Lasenby

    2008-01-01

    .  Following the Bargmann-Wigner formalism, wave-functions for integer and spin-3\\/2 fields are constructed within geometric algebra.\\u000a This is achieved through the multiparticle space-time algebra, where the number of copies of the space-time algebra corresponds\\u000a to the number of spinor fields needed to construct the wave-function. However, this formalism breaks down if a gauge field\\u000a is introduced. This is resolved by introducing

  4. Technical aspects of the evaluation of the overlap of Hartree- Fock- Bogoliubov wave functions

    E-print Network

    L. M. Robledo

    2011-02-10

    Several technical aspects concerning the evaluation of the overlap between two mean field wave functions of the Hartree Fock Bogoliubov type, are discussed. The limit when several orbitals become fully occupied is derived as well as the formula to reduce the dimensionality of the problem when exactly empty orbitals are present. The formalism is also extended to deal with the case where the bases of each of the wave functions are different. Several practical results concerning the evaluation of pfaffians as well as the canonical decomposition of norm overlaps are also discussed in the appendices.

  5. Entanglement, scaling, and the meaning of the wave function in protective measurement

    E-print Network

    Maximilian Schlosshauer; Tangereen V. B. Claringbold

    2014-05-07

    We examine the entanglement and state disturbance arising in a protective measurement and argue that these inescapable effects doom the claim that protective measurement establishes the reality of the wave function. An additional challenge to this claim results from the exponential number of protective measurements required to reconstruct multi-qubit states. We suggest that the failure of protective measurement to settle the question of the meaning of the wave function is entirely expected, for protective measurement is but an application of the standard quantum formalism, and none of the hard foundational questions can ever be settled in this way.

  6. Second-Order Moller-Plesset Perturbation Theory for Molecular Dirac-Hartree-Fock Wave Functions

    NASA Technical Reports Server (NTRS)

    Dyall, Kenneth G.; Arnold, James O. (Technical Monitor)

    1994-01-01

    Moller-Plesset perturbation theory is developed to second order for a selection of Kramers restricted Dirac-Hartree-Fock closed and open-shell reference wave functions. The open-shell wave functions considered are limited to those with no more than two electrons in open shells, but include the case of a two-configuration SCF reference. Denominator shifts are included in the style of Davidson's OPT2 method. An implementation which uses unordered integrals with labels is presented, and results are given for a few test cases.

  7. On wave function renormalization and related aspects in heavy fermion effective field theories

    E-print Network

    Sven Steininger; Ulf-G. Meißner; Nadia Fettes

    1998-08-28

    We reconsider the question of wave function renormalization in heavy fermion effective field theories. In particular, we work out a simple and efficient scheme to define the wave function renormalization with respect to the lowest order heavy fermion propagator. The method presented is free of a set of ambiguities which arise in heavy fermion effective field theories. In this context, we discuss the approaches used in the literature so far. We also calculate the fourth order pion mass contribution to the nucleon mass shift and discuss the tree and loop contributions to the electric Sachs form factor of the nucleon.

  8. Past analogs of recent climate anomalies and impacts in Portugal. Droughts, storms and heat waves

    NASA Astrophysics Data System (ADS)

    Alcoforado, M. J.; Nunes, M. F.

    2009-09-01

    An indexed reconstruction of precipitation variability, based on documentary and instrumental data, has been done for southern Portugal starting in 1675. The descriptions of the extreme events in the documentary sources have also supplied information about their impacts. We will compare past and recent extreme weather events in Portugal, their causes and their impacts on society. We have selected periods of winter droughts, of storms that triggered great floods and of heat waves. There are a number of documentary sources dating from 1693-94 indicating that that there was no rainfall from December 1693 to at least November 1694 with the exception of light showers in June. Several pro-pluvia rogations ceremonies took place all over the country, even in the Northwest that is generally rainy. There are numerous descriptions of the impact of droughts on agriculture, of shortage of cereals, of escalating prices and the subsequent generalised famine. An analogy will be made for the 20th century using the 1980-81 winter drought that lasted roughly the same time and which also had severe social and economic impacts. The decrease in production of hydroelectric energy (50% below average) between January and July 1981 is also pointed out. In both cases, the lack of rainfall was partly due to a ridge that stayed over the Eastern Atlantic and kept Iberia in aerologic shelter. Apart from urban flash floods there are two types of floods in Portugal: (i) floods from the big river basins (Tagus, Mondego and Douro) that are due to the frequent passage of westerly frontal depressions during days or weeks; and (ii) floods of the small river basins due to convective depressions that affect small areas. The December 1739 flood, caused by the overflow of the great rivers, will be compared with the ones that occurred in February 1978. Both were caused by intensive precipitation all over the country at a time when the soil was already saturated with water from previous rainfall. The damages were vast in both occasions including loss of life. Two poems and other documentary sources supply detailed and credible information on the 1739 flood that hit Portugal from North to South. A heat wave in June-July 1842 has been selected. There are already instrumental data available for the former (Franzini station), retrieved from medical journals as well as descriptions of impacts on several regions in the country. The 1842 heat wave will be compared with more recent heat waves like the June 1981 that had very serious impact on public health and on the country's economy. We will also analyse the heat waves of July 1991 and August 2003. The latter was particularly long-lasting with serious consequences ranging from extensive forest fires to losses in agriculture and impact on the population health, although the registered mortality was lower than in 1981 probably due to improved alert systems and Public Health Welfare State.

  9. Numerical Computations and Integrations of the Wave Resistance Green's Function

    NASA Astrophysics Data System (ADS)

    Ponizy, Barbara; Guilbaud, Michel; Ba, Malick

    In order to develop an efficient method, using Kelvin--Havelock singularities, to compute the steady lifting flow around a ship with forward speed, the accuracy of computations of Green's function and boundary integrations have been investigated. The computations have been done using interpolation from tables for the nonoscillatory term of Green's function and using series for the oscillatory one; it has been shown that a region exists, close to the free-surface, where this last term must be computed by complete integration to ensure a prescribed error. Three schemes of boundary integrations have been studied; first boundary integrations have been performed using a Gauss method. Then, to improve accuracy, Fourier and boundary integrations have been interchanged either only for the oscillatory term or for both terms. Numerical results are compared and discussed taking into account both precision and computational time, for a submerged ellipsoid and for a lifting surface-piercing body.

  10. Waves

    NSDL National Science Digital Library

    Mr. Hansen

    2010-11-12

    The following websites are useful tools in understanding how energy is transferred from place to place through waves. Start by downloading the assignment and then begin with website number 1 and continue until you have visited all three websites. Begin by downloading the IA Waves Internet Assignment: IA Waves Internet Assignment You will answer the questions in Microsoft Word and then e-mail the assignment to me. Website #1: Read about basic information on waves and answer the questions from part 1 of the IA Waves Guide: Basic Wave Information Website #2: Follow the instructions for the following ...

  11. Symmetry properties of the S matrix in a fully relativistic distorted-wave treatment of electron-impact ionization

    SciTech Connect

    Pyper, N. C.; Kampp, Marco; Whelan, Colm T. [University Chemical Laboratory, Lensfield Road, Cambridge, CB2 1EW (United Kingdom); Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Silver Street, Cambridge CB3 9EW (United Kingdom); Department of Physics, Old Dominion University, Norfolk, Virginia 23529-0116 (United States)

    2005-05-15

    The symmetry properties of the S matrix in a fully relativistic distorted-wave treatment of electron-impact ionization are investigated. It is shown that the square modulus of the scattering matrix element in which the spin states of all four electrons are determined is not invariant under the reversal of the direction of alignment of all spins. The largest of two contributions to this noninvariance originates from the relativistic modifications of the continuum wave functions induced by the distorting potential of the target atom. A second smaller contribution is manifested on reducing the eight-dimensional matrix elements of the QED covariant propagator to purely spatial two-electron integrals. The triple differential cross section (TDCS) exhibits a spin asymmetry unless the entire scattering process occurs in a single plane. There will be a difference in the TDCS between an (e,2e) event in which the initial beam is polarized parallel or antiparallel with respect to the beam direction even if the target is unpolarized and the final spin states are not determined. The TDCS will remain unchanged if, in addition to reversal of the direction of spin alignment, one appropriate momentum component of one of the two outgoing electrons is reversed.

  12. Impact Wave Monitoring in Soil Using a Dynamic Fiber Sensor Based on Stimulated Brillouin Scattering

    PubMed Central

    Cui, Qingsong; Pamukcu, Sibel; Pervizpour, Mesut

    2015-01-01

    The impact wave response of soil due to a ball drop is monitored on a 30.5 cm by 30.5 cm square soil box using a fiber sensor with dynamic strain sensing capability. The experiments are conducted in real time using a simple one-laser one-modulator configuration with stimulated Brillouin scattering. The embedded BOTDA sensor grid successfully monitored the distribution and evolution of the inner strains of a sand bed during a mass impact on its surface. The measurement of the distributed dynamic strains was possible in several milliseconds and with 1 cm actual location resolution. This paper presents a time-domain signal analysis utilized for determining the dynamic strains in embedded fiber sensor. The results demonstrate the method to be a promising one for detection of subsurface vibration and movement in geotechnical Structure Health Monitoring (SHM). PMID:25856327

  13. Impact wave monitoring in soil using a dynamic fiber sensor based on stimulated brillouin scattering.

    PubMed

    Cui, Qingsong; Pamukcu, Sibel; Pervizpour, Mesut

    2015-01-01

    The impact wave response of soil due to a ball drop is monitored on a 30.5 cm by 30.5 cm square soil box using a fiber sensor with dynamic strain sensing capability. The experiments are conducted in real time using a simple one-laser one-modulator configuration with stimulated Brillouin scattering. The embedded BOTDA sensor grid successfully monitored the distribution and evolution of the inner strains of a sand bed during a mass impact on its surface. The measurement of the distributed dynamic strains was possible in several milliseconds and with 1 cm actual location resolution. This paper presents a time-domain signal analysis utilized for determining the dynamic strains in embedded fiber sensor. The results demonstrate the method to be a promising one for detection of subsurface vibration and movement in geotechnical Structure Health Monitoring (SHM). PMID:25856327

  14. Eikonal approximation in AdS/CFT: Conformal partial waves and finite N four-point functions

    NASA Astrophysics Data System (ADS)

    Cornalba, Lorenzo; Costa, Miguel S.; Penedones, João; Schiappa, Ricardo

    2007-04-01

    We introduce the impact parameter representation for conformal field theory correlators of the form A˜. This representation is appropriate in the eikonal kinematical regime, and approximates the conformal partial wave decomposition in the limit of large spin and dimension of the exchanged primary. Using recent results on the two-point function shock in the presence of a shock wave in anti-de Sitter, and its relation to the discontinuity of the four-point amplitude A across a kinematical branch cut, we find the high spin and dimension conformal partial wave decomposition of all tree-level anti-de Sitter Witten diagrams. We show that, as in flat space, the eikonal kinematical regime is dominated by the T-channel exchange of the massless particle with highest spin ( graviton dominance). We also compute the anomalous dimensions of the high spin OO composites. Finally, we conjecture a formula re-summing crossed-ladder Witten diagrams to all orders in the gravitational coupling.

  15. Differential Impact of Parent Functioning on Infant Social Emotional Functioning During the Transition to Parenthood

    E-print Network

    Carhart, Kathryn Patricia

    2012-07-16

    the ability to react pro-socially to a friend who is upset (Denham, 1998). The development of these competencies in early childhood can impact functioning in later childhood and adolescence. SED has even been deemed the ?foundation? of many areas of child... and adolescent adjustment (Deater-Deckard, 2008). SED in Infants and Toddlers The first several years of a child?s life are important in the development of social and emotional capacities. Within the first several days following birth, infants demonstrate...

  16. Duration and fetch-limited growth functions of wind-generated waves parameterized with three different scaling wind velocities

    Microsoft Academic Search

    Paul A. Hwang

    2006-01-01

    Under steady wind forcing, wave development follows the duration- and fetch-limited growth laws. These growth functions are used extensively to obtain the sea state information when only limited observations of the environmental variables are available. Validation and verification of wave models also employ numerical experiments of duration- and fetch-limited wave growth as benchmark tests. The reference wind speed reported in

  17. The Usefulness of Exponential Wave Function Expansions Employing One- and Two-Body Cluster Operators in Electronic Structure Theory

    NASA Astrophysics Data System (ADS)

    Fan, Peng-Dong; Piecuch, Piotr

    In this paper, the applicability of exponential cluster expansions involving one- and two-body operators in high accuracy ab initio electronic structure calculations is examined. First, the extended coupled-cluster method with singles and doubles (ECCSD) is tested in the demanding studies of systems with strong quasi-degeneracies, including potential energy surfaces involving multiple bond breaking. The numerical results show that the single-reference ECCSD method is capable of providing a qualitatively correct description of quasi-degenerate electronic states and potential energy surfaces involving bond breaking, eliminating, in particular, the failures and the unphysical behavior of standard coupled-cluster methods in similar cases. It is also demonstrated that one can obtain entire potential energy surfaces with millihartree accuracies by combining the ECCSD theory with the non-iterative a posteriori corrections obtained by using the generalized variant of the method of moments of coupled-cluster equations. This is one of the first instances where the relatively simple single-reference formalism, employing only one- and two-body clusters in the design of the relevant energy expressions, provides a highly accurate description of the dynamic and significant non-dynamic correlation effects characterizing quasi-degenerate and multiply bonded systems. Second, an evidence is presented that one may be able to represent the virtually exact ground- and excited-state wave functions of many-electron systems by exponential cluster expansions employing general two-body or one- and two-body operators. Calculations for small many-electron model systems indicate the existence of finite two-body parameters that produce the numerically exact wave functions for ground and excited states. This finding may have a significant impact on future quantum calculations for many-electron systems, since normally one needs triply excited, quadruply excited, and other higher-than-doubly excited Slater determinants, in addition to all singly and doubly excited determinants, to obtain the exact or virtually exact wave functions.

  18. The seismic response of an aquifer to the propagation of an impact generated shock wave: A possible trigger of the Martian outflow channels?

    NASA Technical Reports Server (NTRS)

    Leyva, Ivett A.; Clifford, Stephen M.

    1993-01-01

    Aquifer dilation from shock waves produced by the 8.4 magnitude Alaskan earthquake of 1964 led to water and sediment ejection from the ground up to 400 km away from the earthquake's epicenter. Groundwater disturbances were observed as far away as Perry, Florida (approximately 5500 km), where well water fluctuations with an amplitude of as much as 2.3 m were reported. The martian cratering record provides evidence that the planet has experienced numerous seismic events of a similar, and often much greater, magnitude. Given this fact, and the photogeologic evidence for abundant water in the early crust, the response of a basalt aquifer to the propagation of compressional waves (P-waves) produced by impacts in the 33-1000 km diameter size range were investigated. The resulting one-dimensional changes in effective stress and pore pressure were calculated - as a function of both distance and time - based on the following assumptions: (1) that all of the seismic energy radiated by an impact is transmitted as a single compressional wave; (2) that both the host rock and groundwater are compressible; and (3) that there is no net flow between the water-filled pores.

  19. Bispectrality of $N$-Component KP Wave Functions: A Study in Non-Commutativity

    E-print Network

    Alex Kasman

    2015-06-09

    A wave function of the $N$-component KP Hierarchy with continuous flows generated by $z$ times the powers of an invertible matrix $H$ is constructed from the choice an $MN$-dimensional space of finitely-supported vector distributions. This wave function is shown to be an eigenfunction for a ring of matrix differential operators in $x$ having eigenvalues that are matrix functions of the spectral parameter $z$. If the space of distributions is invariant under left multiplication by $H$, then a matrix coefficient differential-translation operator in $z$ is shown to share this eigenfunction and have an eigenvalue that is a matrix function of $x$. This paper not only generates new examples of bispectral operators, it also explores the consequences of non-commutativity for techniques and objects used in previous investigations.

  20. Operator Dictionaries and Wave Functions in AdS/CFT and dS/CFT

    E-print Network

    Daniel Harlow; Douglas Stanford

    2011-04-21

    Dual AdS/CFT correlators can be computed in two ways: differentiate the bulk partition function with respect to boundary conditions, or extrapolate bulk correlation functions to the boundary. These dictionaries were conjectured to be equivalent by Banks, Douglas, Horowitz, and Martinec. We revisit this question at the level of bulk path integrals, showing that agreement in the presence of interactions requires careful treatment of the renormalization of bulk composite operators. By contrast, we emphasize that proposed dS/CFT analogues of the two dictionaries are inequivalent. Next, we show quite generally that the wave function for Euclidean AdS analytically continues to the dS wave function with Euclidean initial conditions. Most of our arguments consider interacting fields on a fixed background, but in a final section we discuss the inclusion of bulk dynamical gravity.

  1. Artificial reef effect and fouling impacts on offshore wave power foundations and buoys - a pilot study

    NASA Astrophysics Data System (ADS)

    Langhamer, Olivia; Wilhelmsson, Dan; Engström, Jens

    2009-04-01

    Little is known about the effects of offshore energy installations on the marine environment, and further research could assist in minimizing environmental risks as well as in enhancing potential positive effects on the marine environment. While biofouling on marine energy conversion devices on one hand has the potential to be an engineering concern, these structures can also affect biodiversity by functioning as artificial reefs. The Lysekil Project is a test park for wave power located at the Swedish west coast. Here, buoys acting as point absorbers on the surface are connected to generators anchored on concrete foundations on the seabed. In this study we investigated the colonisation of foundations by invertebrates and fish, as well as fouling assemblages on buoys. We examined the influence of surface orientation of the wave power foundations on epibenthic colonisation, and made observations of habitat use by fish and crustaceans during three years of submergence. We also examined fouling assemblages on buoys and calculated the effects of biofouling on the energy absorption of the wave power buoys. On foundations we demonstrated a succession in colonisation over time with a higher degree of coverage on vertical surfaces. Buoys were dominated by the blue mussel Mytilus edulis. Calculations indicated that biofouling have no significant effect in the energy absorption on a buoy working as a point absorber. This study is the first structured investigation on marine organisms associated with wave power devices.

  2. Towards developing drought impact functions to advance drought monitoring and early warning

    NASA Astrophysics Data System (ADS)

    Bachmair, Sophie; Stahl, Kerstin; Hannaford, Jamie; Svoboda, Mark

    2015-04-01

    In natural hazard analysis, damage functions (also referred to as vulnerability or susceptibility functions) relate hazard intensity to the negative effects of the hazard event, often expressed as damage ratio or monetary loss. While damage functions for floods and seismic hazards have gained considerable attention, there is little knowledge on how drought intensity translates into ecological and socioeconomic impacts. One reason for this is the multifaceted nature of drought affecting different domains of the hydrological cycle and different sectors of human activity (for example, recognizing meteorological - agricultural - hydrological - socioeconomic drought) leading to a wide range of drought impacts. Moreover, drought impacts are often non-structural and hard to quantify or monetarize (e.g. impaired navigability of streams, bans on domestic water use, increased mortality of aquatic species). Knowledge on the relationship between drought intensity and drought impacts, i.e. negative environmental, economic or social effects experienced under drought conditions, however, is vital to identify critical thresholds for drought impact occurrence. Such information may help to improve drought monitoring and early warning (M&EW), one goal of the international DrIVER project (Drought Impacts: Vulnerability thresholds in monitoring and Early-warning Research). The aim of this study is to test the feasibility of designing "drought impact functions" for case study areas in Europe (Germany and UK) and the United States to derive thresholds meaningful for drought impact occurrence; to account for the multidimensionality of drought impacts, we use the broader term "drought impact function" over "damage function". First steps towards developing empirical drought impact functions are (1) to identify meaningful indicators characterizing the hazard intensity (e.g. indicators expressing a precipitation or streamflow deficit), (2) to identify suitable variables representing impacts, damage, or loss due to drought, and (3) to test different statistical models to link drought intensity with drought impact information to derive meaningful thresholds. While the focus regarding drought impact variables lies on text-based impact reports from the European Drought Impact report Inventory (EDII) and the US Drought Impact Reporter (DIR), the information gain through exploiting other variables such as agricultural yield statistics and remotely sensed vegetation indices is explored. First results reveal interesting insights into the complex relationship between drought indicators and impacts and highlight differences among drought impact variables and geographies. Although a simple intensity threshold evoking specific drought impacts cannot be identified, developing drought impact functions helps to elucidate how drought conditions relate to ecological or socioeconomic impacts. Such knowledge may provide guidance for inferring meaningful triggers for drought M&EW and could have potential for a wide range of drought management applications (for example, building drought scenarios for testing the resilience of drought plans or water supply systems).

  3. The Impact of Chromospheric Activity on Observed Initial Mass Functions

    E-print Network

    Stassun, Keivan G; Dupuy, Trent; Kratter, Kaitlin

    2014-01-01

    Using recently established empirical calibrations for the impact of chromospheric activity on the radii, effective temperatures, and estimated masses of active low-mass stars and brown dwarfs, we reassess the shape of the initial mass function (IMF) across the stellar/substellar boundary in the Upper Sco star-forming region (age 5-10 Myr). We adjust the observed effective temperatures to warmer values using the observed strength of the chromospheric H$\\alpha$ emission, and redetermine the estimated masses of objects using pre--main-sequence evolutionary tracks in the H-R diagram. The effect of the activity-adjusted temperatures is to shift the objects to higher masses by 3-100%. While the slope of the resulting IMF at substellar masses is not strongly changed, the peak of the IMF does shift from ~0.06 to ~0.11 Msun. Moreover, for objects with masses ~0.2 Msun, the ratio of brown dwarfs to stars changes from ~80% to ~33%. These results suggest that activity corrections are essential for studies of the substell...

  4. Perturbation theory for multiphoton ionization without knowledge of the final-state wave function

    NASA Astrophysics Data System (ADS)

    Shakeshaft, Robin

    1999-08-01

    We show how the inclusive rate of decay of an atomic system by absorption of any number N of photons can be calculated at Nth order of perturbation theory without employing the final-state (continuum) wave function. We give a computationally useful formula which involves only the response function for a system perturbed by absorption of N photons. In the case of a two-electron system, the contributions to the inclusive rate from individual channels can be separated using projection operators.

  5. The pion light-cone wave function Phipi on the lattice: a partonic signal?

    Microsoft Academic Search

    A. Abada; Ph. Boucaud; G. Herdoiza; J. P. Leroy; J. Micheli; O. Pne; J. Rodríguez-Quintero

    2001-01-01

    We determine the conditions required to study the pion light-cone wave function Phipi with a new method: a direct display of the partons constituting the pion. We present the preliminary results of a lattice computation of Phipi following this direction. An auxiliary scalar-quark is introduced. The spectroscopy of its bound states is studied. We observe some indications of a partonic

  6. MIMO Radar Space-Time Adaptive Processing Using Prolate Spheroidal Wave Functions

    E-print Network

    Vaidyanathan, P. P.

    1 MIMO Radar Space-Time Adaptive Processing Using Prolate Spheroidal Wave Functions Chun-Yang Chen and P. P. Vaidyanathan, Fellow, IEEE Abstract--In the traditional transmitting beamforming radar system- output (MIMO) radar system, the transmitter sends nonco- herent (possibly orthogonal) broad (possibly

  7. Foldy-Wouthuysen wave functions and conditions of transformation between Dirac and Foldy-Wouthuysen representations

    SciTech Connect

    Neznamov, V. P. [Russian Federal Nuclear Center-The All-Russian Research Institute of Experimental Physics, Sarov 607190 (Russian Federation); Silenko, A. J. [Research Institute of Nuclear Problems, Belarusian State University, Minsk 220030 (Belarus)

    2009-12-15

    The block diagonalization of the Hamiltonian is not sufficient for the transformation to the Foldy-Wouthuysen (FW) representation. The conditions enabling the transition from the Dirac representation to the FW one are formulated and proven. The connection between wave functions in the two representations is derived. The results obtained allow calculating expectation values of operators corresponding to main classical quantities.

  8. Receiver functions from regional P waves Jeffrey Park and Vadim Levin

    E-print Network

    Levin, Vadim

    with teleseismic RFs. At RAYN the moveout of the Moho-converted Ps phase, relative to direct P, follows the predictions of the IASP91 earth model well. The Moho-converted Ps phase shows complexity associated functions. Key words: anisotropy, body waves, crustal structure, Moho discontinuity, seismic coda, synthetic

  9. Frequency-Domain Green's Functions for Radar Waves in Heterogeneous 2.5D Media

    EPA Science Inventory

    Green?s functions for radar waves propagating in heterogeneous media may be calculated in the frequency domain using a hybrid of two numerical methods. The model is defined in the Cartesian coordinate system, and its electromagnetic properties may vary in the x and z directions, ...

  10. Chiral Symmetry Breaking and Meson Wave Functions in Soft-Wall AdS/QCD

    E-print Network

    Gutsche, Thomas; Schmidt, Ivan; Vega, Alfredo

    2012-01-01

    We consider mesons composed of light and heavy quarks and discuss the construction of the corresponding meson wave functions in soft-wall AdS/QCQ. We specifically take care that constraints imposed by chiral symmetry breaking and by the heavy quark limit are fulfilled. The main results are: i) the wave functions of light mesons have a nontrivial dependence on the current quark mass, which gives rise to a mass spectrum consistent with the one including explicit breaking of chiral symmetry; ii) the wave functions of heavy-light mesons generate their correct mass spectrum, the mass splittings of vector and pseudoscalar states, and the correct scaling of leptonic decay constants f(Q \\bar q) \\sim 1/sqrt(mQ); iii) the wave functions of heavy quarkonia produce their correct mass spectrum and lead to a scaling behaviour of the leptonic decay constants f(Q \\bar Q) \\sim sqrt(mQ) and f(c \\bar b) \\sim mc/sqrt(mb) at mc << mb, consistent with potential models and QCD sum rules.

  11. Chiral Symmetry Breaking and Meson Wave Functions in Soft-Wall AdS/QCD

    E-print Network

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

    2013-03-01

    We consider mesons composed of light and heavy quarks and discuss the construction of the corresponding meson wave functions in soft-wall AdS/QCD. We specifically take care that constraints imposed by chiral symmetry breaking and by the heavy quark limit are fulfilled. The main results are: i) the wave functions of light mesons have a nontrivial dependence on the current quark mass, which gives rise to a mass spectrum consistent with the one including explicit breaking of chiral symmetry; ii) the wave functions of heavy-light mesons generate their correct mass spectrum, the mass splittings of vector and pseudoscalar states, and the correct scaling of leptonic decay constants f(Q \\bar q) \\sim 1/sqrt(mQ); iii) the wave functions of heavy quarkonia produce their correct mass spectrum and lead to a scaling behaviour of the leptonic decay constants f(Q \\bar Q) \\sim sqrt(mQ) and f(c \\bar b) \\sim mc/sqrt(mb) at mc << mb, consistent with potential models and QCD sum rules.

  12. A three-parameter wave function for the hydrogen molecule ion

    Microsoft Academic Search

    R G Clark; E Theal Stewart

    1969-01-01

    In minimizing the electronic energy of the ground state of the hydrogen molecule ion H2+ with respect to the parameters p, ? and ? in the elaborated Guillemin-Zener wave function ? = (1 + pR?) exp(-?R?) cosh(?R?)we have located two minima, corresponding to p > 0 and p < 0. We confirm Bhalla and Khubchandani's calculations for p 0 (the

  13. Pixel level optical-transfer-function design based on the surface-wave-interferometry aperture

    E-print Network

    Yang, Changhuei

    be directly incorporated onto optical sensors to accomplish OTF design on the pixel level. The whole aperture. J. Garcia-Vidal, and T. W. Ebbesen, "Beaming light from a subwavelength aperture," Science 297Pixel level optical-transfer-function design based on the surface-wave-interferometry aperture

  14. Maximally localized Wannier functions constructed from projector-augmented waves or ultrasoft pseudopotentials

    Microsoft Academic Search

    A. Ferretti; A. Calzolari; B. Bonferroni; R. Di Felice

    2007-01-01

    We report a theoretical scheme that enables the calculation of maximally localized Wannier functions within the formalism of projector-augmented waves (PAW), which also includes the ultrasoft pseudopotential (USPP) approach. We give a description of the basic underlying formalism and explicitly write out all the required matrix elements using the common ingredients of the PAW\\/USPP theory. We report an implementation of

  15. Accuracy of electronic wave functions in quantum Monte Carlo: The effect of high-order correlations

    E-print Network

    Nightingale, Peter

    surface systematically bias the expectation values. The usual variational and mixed-estimators2 both for expectation values of physical in- terest and for the variance of the Monte Carlo estimators, as the trial wave function approaches an exact eigenstate of the Hamiltonian, the energy and expectation values

  16. Exact wave functions and coherent states of a damped driven harmonic oscillator

    Microsoft Academic Search

    H. G. Oh; H. R. Lee; Thomas F. George; C. I. Um

    1989-01-01

    For a damped harmonic oscillator forced by a time-dependent field, the exact wave function is obtained by three different methods: (i) path integral, (ii) second quantization, and (iii) dynamical invariant. The explicit form of the dynamical invariant involves a solution to a corresponding auxiliary equation. The coherent states, defined as eigenstates of a new destruction operator, form a nonorthogonal, overcomplete

  17. Exact wave functions and coherent states of a damped driven harmonic oscillator

    Microsoft Academic Search

    H. G. Oh; H. R. Lee; Thomas F. George; C. I. Um

    1989-01-01

    For a damped oscillator forced by a time-dependent field, the exact wave function is obtained by three different methods: (1) Path-integral, (2) Second quantization and (3) Dynamical invariant. The explicit form of the dynamical invariant involves a solution to a corresponding auxiliary equation. The coherent states, defined as eigenstates of a new destruction operator, form a nonorthogonal, over complete set

  18. Wave-function Monte Carlo method for simulating conditional master equations

    SciTech Connect

    Jacobs, Kurt [Department of Physics, University of Massachusetts at Boston, Boston, Massachusetts 02125 (United States) and Hearne Institute for Theoretical Physics, Louisiana State University, Baton Rouge, Louisiana 70803 (United States)

    2010-04-15

    Wave-function Monte Carlo methods are an important tool for simulating quantum systems, but the standard method cannot be used to simulate decoherence in continuously measured systems. Here I present a Monte Carlo method for such systems. This was used to perform the simulations of a continuously measured nanoresonator in [Phys. Rev. Lett. 102, 057208 (2009)].

  19. Relativistic invariance of dispersion-relations and their associated wave-operators and Green-functions

    Microsoft Academic Search

    Dan Censor

    2008-01-01

    Identifying invariance properties helps in simplifying calculations and consolidating concepts. Presently the special relativistic invariance of dispersion relations and their associated scalar wave operators is investigated for general dispersive homogeneous linear media. Invariance properties of the four-dimensional Fourier transform integrals is demonstrated, from which the invariance of the scalar Green function is inferred. Dispersion relations and the associated group velocities

  20. Quantum wave function simulation of the resonance fluorescence spectrum from one-dimensional optical molasses

    Microsoft Academic Search

    P. Marte; R. Dum; R. Taïeb; P. D. Lett; P. Zoller

    1993-01-01

    Using recently developed quantum wave function techniques, we have performed a simulation of 85Rb atoms in a one-dimensional optical molasses, formed from counterpropagating laser beams with orthogonal linear polarizations. Both internal and external degrees of freedom are treated quantum mechanically in one dimension and the spectrum of resonance fluorescence is calculated and compared to recent experiments. Excellent agreement is obtained

  1. A higher-order spectral element for wave propagation analysis in functionally graded materials

    Microsoft Academic Search

    A. Chakraborty; S. Gopalakrishnan

    2004-01-01

    Summary. A new higher-order spectral element (SE) is developed for wave propagation analysis of a functionally graded material (FGM) beam in the presence of thermal and mechanical loading. The element is based on first order shear deformation theory (FSDT) and takes into account the depthwise contraction due to Poisson’s ratio. A new method of element formulation is employed, which is

  2. Joint inversion of receiver functions, surface wave dispersion, and magnetotelluric data

    E-print Network

    Jones, Alan G.

    Click Here for Full Article Joint inversion of receiver functions, surface wave dispersion 2009; accepted 16 December 2009; published 30 April 2010. [1] We present joint inversion to assume for the seismic data. This additional information helps to assess the validity of the joint model

  3. Analysis of electromagnetic wave propagation in multilayered media using dyadic Green's functions

    Microsoft Academic Search

    Gervasio Protásio dos Santos Cavalcante; David Anthony Rogers; Attílio José Giarola

    1982-01-01

    The propagation of electromagnetic waves in media with various horizontal layers has been ana- lyzed. The electromagnetic fields outside the source region were obtained from the dyadic Green's functions for the case of media with three and four layers and for horizontal and vertical electric dipoles. These results agree with those obtained using Hertz potentials. One of the major results

  4. A computational approach for investigating unsteady turbine blade heat transfer due to shock wave impact

    SciTech Connect

    Reid, T.V.; Schetz, J.A.; Diller, T.E.; Ng, W.F.

    1999-07-01

    The effects of shock wave passing on unsteady turbine blade heat transfer are investigated. A numerical approach is developed to simulate the flow physics present in a previously performed unsteady wind tunnel experiment which included unheated and heated flows over a cascade of highly loaded turbine blades. After the flow over the blades was established, a shock with a pressure ratio of 1.1 was introduced into the wind tunnel test section. As the shock wave strikes the blade, time resolved pressure, temperature and heat transfer data are available from the instrumentation. This computational approach enables the transient history of flow variables to be observed prior to and during the shock/boundary layer interaction. Simplifications are made to the complete unsteady, compressible Navier-Stokes equations to produce a manageable set of equations appropriate to this flow. The simplified governing equations only allow the numerical simulation to address normally impacting shock waves, which were found experimentally to produce the highest levels of heat transfer. The pre-shock wind tunnel flow conditions were used as input. The solutions were inserted into a first-order time response model, so that the heat flux gage time response could be simulated. The comparison of this numerically simulated data showed generally good quantitative and fair agreement with the experimentally obtained data. Results showed that when the heat transfer was averaged over a 50 {micro}second time period, typically of real blade-passing events, the increase in heat transfer is 50%. Integrating over the time period from when the shock first enters the boundary layer, travels down to the surface, reflects and then exits the boundary layer, a factor of six increase in heat transfer is observed above the value prior shock impact.

  5. Electromagnetic wave emitting products and "Kikoh" potentiate human leukocyte functions.

    PubMed

    Niwa, Y; Iizawa, O; Ishimoto, K; Jiang, X; Kanoh, T

    1993-09-01

    Tourmaline (electric stone, a type of granite stone), common granite stone, ceramic disks, hot spring water and human palmar energy (called "Kikoh" in Japan and China), all which emit electromagnetic radiation in the far infrared region (wavelength 4-14 microns). These materials were thus examined for effects on human leukocyte activity and on lipid peroxidation of unsaturated fatty acids. It was revealed that these materials significantly increased intracellular calcium ion concentration, phagocytosis, and generation of reactive oxygen species in neutrophils, and the blastogenetic response of lymphocytes to mitogens. Chemotactic activity by neutrophils was also enhanced by exposure to tourmaline and the palm of "Kikohshi" i.e., a person who heals professionally by the laying on of hands. Despite the increase in reactive oxygen species generated by neutrophils, lipid peroxidation from unsaturated fatty acid was markedly inhibited by these four materials. The results suggest that materials emitting electromagnetic radiation in the far infrared range, which are widely used in Japan for cosmetic, therapeutic, and preservative purposes, appear capable of potentiating leukocyte functions without promoting oxidative injury. PMID:8406976

  6. The impact of temperature inversions on gravity waves and downslope windstorms

    NASA Astrophysics Data System (ADS)

    Opsanger Jonassen, Marius; Ólafsson, Haraldur; Ágústsson, Hálfdán

    2015-04-01

    In a set of idealised 3D numerical simulations using WRF, we systematically investigate the impact of temperature inversions and their elevation above ground on flow over and around a mountain. Our results from these simulations confirm the potentially substantial impact of inversions on mountain flow, that have previously been found both in real case studies and in the case of idealised simulations, that mainly have been performed in 2D. Based on the numerical simulations, a flow diagramme is presented, where the flow perturbations are shown as functions of strength and elevation of the inversions.

  7. Universal Probability Distribution for the Wave Function of a Quantum System Entangled with Its Environment

    E-print Network

    Sheldon Goldstein; Joel L. Lebowitz; Christian Mastrodonato; Roderich Tumulka; Nino Zanghi

    2015-02-10

    A quantum system (with Hilbert space $\\mathscr{H}_1$) entangled with its environment (with Hilbert space $\\mathscr{H}_2$) is usually not attributed a wave function but only a reduced density matrix $\\rho_1$. Nevertheless, there is a precise way of attributing to it a random wave function $\\psi_1$, called its conditional wave function, whose probability distribution $\\mu_1$ depends on the entangled wave function $\\psi\\in\\mathscr{H}_1\\otimes\\mathscr{H}_2$ in the Hilbert space of system and environment together. It also depends on a choice of orthonormal basis of $\\mathscr{H}_2$ but in relevant cases, as we show, not very much. We prove several universality (or typicality) results about $\\mu_1$, e.g., that if the environment is sufficiently large then for every orthonormal basis of $\\mathscr{H}_2$, most entangled states $\\psi$ with given reduced density matrix $\\rho_1$ are such that $\\mu_1$ is close to one of the so-called GAP (Gaussian adjusted projected) measures, $GAP(\\rho_1)$. We also show that, for most entangled states $\\psi$ from a microcanonical subspace (spanned by the eigenvectors of the Hamiltonian with energies in a narrow interval $[E,E+\\delta E]$) and most orthonormal bases of $\\mathscr{H}_2$, $\\mu_1$ is close to $GAP(\\mathrm{tr}_2 \\rho_{mc})$ with $\\rho_{mc}$ the normalized projection to the microcanonical subspace. In particular, if the coupling between the system and the environment is weak, then $\\mu_1$ is close to $GAP(\\rho_\\beta)$ with $\\rho_\\beta$ the canonical density matrix on $\\mathscr{H}_1$ at inverse temperature $\\beta=\\beta(E)$. This provides the mathematical justification of our claim in [J. Statist. Phys. 125:1193 (2006), http://arxiv.org/abs/quant-ph/0309021] that $GAP$ measures describe the thermal equilibrium distribution of the wave function.

  8. Analytic solution of the Schroedinger equation for the Coulomb-plus-linear potential. I. The wave functions

    SciTech Connect

    Plante, Guillaume; Antippa, Adel F. [Physics Department, Columbia University, New York, New York 10027 (United States); Departement de Physique, Universite du Quebec a Trois-Rivieres, Trois-Rivieres, Quebec, G9A 5H7 (Canada)

    2005-06-01

    We solve the Schroedinger equation for a quark-antiquark system interacting via a Coulomb-plus-linear potential, and obtain the wave functions as power series, with their coefficients given in terms of the combinatorics functions.

  9. Probability Distribution Functions of freak-waves: nonlinear vs linear model

    NASA Astrophysics Data System (ADS)

    Kachulin, Dmitriy; Dyachenko, Alexander; Zakharov, Vladimir

    2015-04-01

    No doubts that estimation of probability of freak-wave appearing at the surface of ocean has practical meaning. Among different mechanisms of this phenomenon linear dispersion and modulational instability are generally recognized. For linear equation of water waves Probability Distribution Functions (PDF) can be calculated analytically and it is nothing but normal Gaussian distribution for surface elevation. Or it is Rayleigh distribution for absolute values of elevations. For nonlinear waves one can expect something different. In this report we consider and compare these two mechanism for various levels of nonlinearity. We present results of numerical experiments on calculation of Probability Distribution Functions for surface elevations of waters waves both for nonlinear and linear models. Both model demonstrates Rayleigh distribution of surface elevations. However dispersion of PDF for nonlinear case is much larger than for linear case. This work was supported by the Grant "Wave turbulence: theory, numerical simulation, experiment" #14-22-00174 of Russian Science Foundation. Numerical simulation was performed on the Informational Computational Center of the Novosibirsk State University.

  10. Analysis and measurement of the modulation transfer function of harmonic shear wave induced phase encoding imaging

    PubMed Central

    McAleavey, Stephen A.

    2014-01-01

    Shear wave induced phase encoding (SWIPE) imaging generates ultrasound backscatter images of tissue-like elastic materials by using traveling shear waves to encode the lateral position of the scatters in the phase of the received echo. In contrast to conventional ultrasound B-scan imaging, SWIPE offers the potential advantages of image formation without beam focusing or steering from a single transducer element, lateral resolution independent of aperture size, and the potential to achieve relatively high lateral resolution with low frequency ultrasound. Here a Fourier series description of the phase modulated echo signal is developed, demonstrating that echo harmonics at multiples of the shear wave frequency reveal target k-space data at identical multiples of the shear wavenumber. Modulation transfer functions of SWIPE imaging systems are calculated for maximum shear wave acceleration and maximum shear constraints, and compared with a conventionally focused aperture. The relative signal-to-noise ratio of the SWIPE method versus a conventionally focused aperture is found through these calculations. Reconstructions of wire targets in a gelatin phantom using 1 and 3.5?MHz ultrasound and a cylindrical shear wave source are presented, generated from the fundamental and second harmonic of the shear wave modulation frequency, demonstrating weak dependence of lateral resolution with ultrasound frequency. PMID:24815265

  11. Development of new impact functions for global risk caused by climate change

    NASA Astrophysics Data System (ADS)

    Miyazaki, C.

    2014-12-01

    The purpose of our study is to identify and quantify global-scale risks which can be caused by future climate change. In particular, we focus on the global-scale risks which have critical impacts to human environments. Use of impact functions is one of the common way to quantify global-scale risks. Output of impact function is climate impacts (e.g. economic damage by temperature increasing) and input can be global temperature increasing and/or socioeconomic condition (e.g. GDP). As the first step of study, we referred to AR5 WG II report (AR5, hereafter) and comprehensive inventories of climate change risks developed by Strategic R&D Area Project of the Environment Research and Technology Development Fund (ICA-RUS project). Then we extracted information which can be used to develop impact function from them. By following SPM/AR5, we focused on 11 sectors and extracted quantitative description on climate impacts from the AR5 and paper/reports cited in AR5. As a result, we identified about 40 risk items to focus as global-scale risks by climate change. Using the collected information, we tentatively made impact function on sea level rise and so on. In addition, we also extracted the impact functions used in Integrated Assessment Models (IAMs). The literature survey on IAM suggested the risk items considered in IAMs are limited. For instance, although FUND model provides detailed impact functions compared with most of other IAMs, its impact functions deal with only several sectors (e.g. agriculture, forestry, biodiversity, sea level rise, human health, energy demand and water resources). The survey on impact functions in IAMs also suggested impact function for abrupt climate change (so-called Tipping Element) is premature. Moreover, as example for quantifying health risk by our calculation, we also present the result on global-scale projection of the health burden attributable to childhood undernutrition (Ishida et al., 2014, ERL).

  12. Quantum gravitational collapse of a scalar field and the wave function of black hole decay

    NASA Astrophysics Data System (ADS)

    Tomimatsu, Akira

    1995-10-01

    We develop a quantum description of spherically symmetric gravitational collapse of a massless scalar field. The canonical quantization procedure is applied to a minisuperspace model in which the four-metric and scalar field variables are restricted to a self-similar functional form. Our main purpose is to propose a mechanism of black hole decay in terms of a time evolution of the wave function defined on the minisuperspace. For the self-similar classical dynamics there exists a one-parameter family of solutions for the Einstein-scalar equations, and the Hamiltonian turns out to play the role of the critical parameter which separates the supercritical solution corresponding to a black hole formation from the subcritical one corresponding to a wave reflection to infinity. We derive a set of the eigenfunctions of the quantum Hamiltonian operator, which is interpreted to be the quantum version of the supercritical and subcritical solutions. One of the metric components is also treated as a quantum operator which does not commute with the Hamiltonian operator. The expansion of the eigenfunction of the metric operator in terms of the Hamiltonian eigenfunctions motivates us to introduce the superposition principle and the time-dependent Schrödinger equation which lead to the uncertainty of the Hamiltonian eigenvalue. Then we study the time evolution of the initial black hole state, which is chosen to be one of the supercritical Hamiltonian eigenstates. We arrive at the conclusion that the time evolution toward black hole decay is essentially due to the breakdown of orthogonality of the Hamiltonian eigenfunctions: The quantum black hole behaves like a wave packet written by a superposition of the various subcritical states. The localized structure of the black hole wave packet begins to spread as each subcritical state evolves with time according to the Schrödinger equation. We can estimate the decay time and find the final behavior of the wave function describing an outgoing flux of scalar waves observable at future null infinity.

  13. Asymptotic Green function for S waves in the kiss singularity ViFODY#9DYU\\XN

    E-print Network

    Cerveny, Vlastislav

    249 Asymptotic Green function for S waves in the kiss singularity ViFODY#9DYU\\þXN Geophy­wave elastodynamic Green function in the kiss singularity in anisotropic media. In contrast to standard asymptotics. This integral is specified for the kiss singularity along the symmetry axis in transversely isotropic media

  14. G"oteborg-ITP-96-10 A class of ansatz wave functions for 1D spin systems and their

    E-print Network

    Östlund, Stellan

    of ansatz wave functions for 1D spin systems and their relation to DMRG* *ormalization group (DMRG)2;3method which since then has had a spectacular success in calcula* *ting ground, the DMRG ground state leads to a spe* *cial ansatz form for the wave function, demonstrating

  15. Approximated seventh order calculation of vacuum wave function of 2+1 dimensional SU(2) lattice gauge theory

    E-print Network

    Ping Hui; Xi-Yan Fang; Ting-yun Shi

    2004-08-24

    Using the coupled cluster expansion with the random phase approximation, we calculate the long wavelength vacuum wave function and the vacuum energy of 2+1 dimensional Hamiltonian SU(2) lattice gauge theory (LGT) up to the seventh order. The coefficients $\\mu_0$, $\\mu_2$ of the vacuum wave function show good scaling behavior and convergence in high order calculations.

  16. Evaluation of S2 for correlated wave functions and spin projection of unrestricted Mbller-Plesset perturbation theory

    E-print Network

    Schlegel, H. Bernhard

    Evaluation of S2 for correlated wave functions and spin projection of unrestricted Mbller-Plesset perturbation theory Wei Chena) and H. Bernhard Schlegelb) Department of Chemistry,WayneState University diagnostic tool for judging the quality of correlated wave functions. A production code has been developed

  17. Wave function renormalization constants and one-particle form factors in $D_{l}^{(1)}$ Toda field theories

    E-print Network

    Vadim A. Brazhnikov

    1998-09-22

    We apply the method of angular quantization to calculation of the wave function renormali- zation constants in $D_{l}^{(1)}$ affine Toda quantum field theories. A general formula for the wave function renormalization constants in ADE Toda field theories is proposed. We also calculate all one-particle form factors and some of the two-particle form factors of an exponential field.

  18. Preliminary Results for Crustal Structure in Southeastern Africa from P-wave Receiver Functions

    NASA Astrophysics Data System (ADS)

    Kachingwe, M.; Nyblade, A.; Mulibo, G. D.; Mulowezi, A.; Kunkuta, E.; De Magalhães, V.; Wiens, D. A.; Wysession, M. E.; Julia, J.

    2013-12-01

    The crustal structure of southeastern Africa is investigated by modeling P-wave receiver functions using H-k stacking and joint inversion methods. P-wave receiver functions are analyzed for 29 broadband seismic stations in Zambia, Malawi and Mozambique. Estimates for the Moho depth and Poisson's ratio are determined from H-k stacking, and estimates for the shear wave velocity are determined by the joint inversion of receiver functions and surface wave dispersion. Preliminary results show that Moho depths beneath southeastern Africa range from 32 km to 51 km. Thicker crust is found in Proterozoic terrains, such as the Irumide Belt, while thinner crust is found in reworked Archean terrains, such as the Bangweulu Block. These results are consistent with previous studies and global averages for Precambrian terrains. The preliminary results also show a range of Poisson's ratios from 0.2 to 0.3. These new results for southeastern Africa are being combined with similar results from elsewhere in eastern and southern Africa to improve our understanding of African crustal structure.

  19. Preliminary Results for Crustal Structure in Southeastern Africa from P-wave Receiver Functions

    NASA Astrophysics Data System (ADS)

    Kachingwe, M.; Nyblade, A.; Mulibo, G.; Mulowezi, A.; Kunkuta, E.; De Magalhães, V.; Wysession, M. E.; Wiens, D. A.; Julia, J.

    2012-12-01

    The crustal structure of southeastern Africa is investigated by modeling P-wave receiver functions using H-k stacking and joint inversion methods. P-wave receiver functions are analyzed for 29 broadband seismic stations in Zambia, Malawi and Mozambique. Estimates for the Moho depth and Poisson's ratio are determined from H-k stacking, and estimates for the shear wave velocity are determined by the joint inversion of receiver functions and surface wave dispersion. Preliminary results show that Moho depths beneath southeastern Africa range from 32 km to 51 km. Thicker crust is found in Proterozoic terrains, such as the Irumide Belt, while thinner crust is found in reworked Archean terrains, such as the Bangweulu Block. These results are consistent with previous studies and global averages for Precambrian terrains. The preliminary results also show a range of Poisson's ratios from 0.2 to 0.3. These new results for southeastern Africa are being combined with similar results from elsewhere in eastern and southern Africa to improve our understanding of African crustal structure.

  20. Density Functional Study of the Transport and Electronic Properties of Waved Graphene Nanoribbons

    NASA Astrophysics Data System (ADS)

    Hammouri, Mahmoud; Vasiliev, Igor

    2015-03-01

    First principles ab initio calculations are employed to study the electronic and transport properties of waved graphene nanoribbons. Our calculations are performed using the SIESTA and TRANSIESTA density functional electronic structure codes. We find that the band gaps of graphene nanoribbons with symmetrical edges change very slightly with the increasing compression, whereas the band gaps of nanoribbons with asymmetrical edges change significantly. The computed IV-characteristics of the waved graphene nanoribbons with different compression ratios reveal the effect of compression on the transport properties of graphene nanoribbons. Supported by NMSU GREG Award and by NSF CHE-1112388.

  1. Effect of wave-function localization on the time delay in photoemission from surfaces

    SciTech Connect

    Zhang, C.-H.; Thumm, U. [Department of Physics, Kansas State University, Manhattan, Kansas 66506 (United States)

    2011-12-15

    We investigate streaking time delays in the photoemission from a solid model surface as a function of the degree of localization of the initial-state wave functions. We consider a one-dimensional slab with lattice constant a{sub latt} of attractive Gaussian-shaped core potentials of width {sigma}. The parameter {sigma}/a{sub latt} thus controls the overlap between adjacent core potentials and localization of the electronic eigenfunctions on the lattice points. Small values of {sigma}/a{sub latt}<<1 yield lattice eigenfunctions that consist of localized atomic wave functions modulated by a ''Bloch-envelope'' function, while the eigenfunctions become delocalized for larger values of {sigma}/a{sub latt} > or approx 0.4. By numerically solving the time-dependent Schroedinger equation, we calculate photoemission spectra from which we deduce a characteristic bimodal shape of the band-averaged photoemission time delay: as the slab eigenfunctions become increasingly delocalized, the time delay quickly decreases near {sigma}/a{sub latt}=0.3 from relatively large values below {sigma}/a{sub latt}{approx}0.2 to much smaller delays above {sigma}/a{sub latt}{approx}0.4. This change in wave-function localization facilitates the interpretation of a recently measured apparent relative time delay between the photoemission from core and conduction-band levels of a tungsten surface.

  2. Harmonic-oscillator excitations of precise few-body wave functions

    E-print Network

    W. Horiuchi; Y. Suzuki

    2014-08-21

    A method for calculating the occupation probability of the number of harmonic oscillator (HO) quanta is developed for a precise few-body wave function obtained in a correlated Gaussian basis. The probability distributions of two- to four-nucleon wave functions obtained using different nucleon- nucleon (NN) interactions are analyzed to gain insight into the characteristic behavior of the various interactions. Tensor correlations as well as short-range correlations play a crucial role in enhancing the probability of high HO excitations. For the excited states of 4He, the interaction dependence is much less because high HO quanta are mainly responsible for describing the relative motion function between the 3N+N (3H+p and 3He+n) clusters.

  3. On the Quantum Mechanical Wave Function as a Link Between Cognition and the Physical World A Role for Psychology

    E-print Network

    Snyder, D

    2002-01-01

    A straightforward explanation of fundamental tenets of quantum mechanics concerning the wave function results in the thesis that the quantum mechanical wave function is a link between human cognition and the physical world. The reticence on the part of physicists to adopt this thesis is discussed. A comparison is made to the behaviorists' consideration of mind, and the historical roots of how the problem concerning the quantum mechanical wave function arose are discussed. The basis for an empirical demonstration that the wave function is a link between human cognition and the physical world is provided through developing an experiment using methodology from psychology and physics. Based on research in psychology and physics that relied on this methodology, it is likely that Einstein, Podolsky, and Rosen's theoretical result that mutually exclusive wave functions can simultaneously apply to the same concrete physical circumstances can be implemented on an empirical level.

  4. Modeling the functional network of primary intercellular Ca$^{2+}$ wave propagation in astrocytes and its application to study drug effects

    E-print Network

    Marcelo Pires; Frank Raischel; Sandra Vaz; Andreia Cruz-Silva; Ana Sebastião; Pedro G. Lind

    2014-06-10

    We introduce a simple procedure of multivariate signal analysis to uncover the functional connectivity among cells composing a living tissue and describe how to apply it for extracting insight on the effect of drugs in the tissue. The procedure is based on the covariance matrix of time resolved activity signals. By determining the time-lag that maximizes covariance, one derives the weight of the corresponding connection between cells. Introducing simple constraints, it is possible to conclude whether pairs of cells are functionally connected and in which direction. After testing the method against synthetic data we apply it to study intercellular propagation of Ca$^{2+}$ waves in astrocytes following an external stimulus, with the aim of uncovering the functional cellular connectivity network. Our method proves to be particularly suited for this type of networking signal propagation where signals are pulse-like and have short time-delays, and is shown to be superior to standard methods, namely a multivariate Granger algorithm. Finally, based the statistical analysis of the connection weight distribution, we propose simple measures for assessing the impact of drugs on the functional connectivity between cells.

  5. Delta shock waves with Dirac delta function in both components for systems of conservation laws

    NASA Astrophysics Data System (ADS)

    Yang, Hanchun; Zhang, Yanyan

    2014-12-01

    We study a class of non-strictly and weakly hyperbolic systems of conservation laws which contain the equations of geometrical optics as a prototype. The Riemann problems are constructively solved. The Riemann solutions include two kinds of interesting structures. One involves a cavitation where both state variables tend to zero forming a singularity, the other is a delta shock wave in which both state variables contain Dirac delta function simultaneously. The generalized Rankine-Hugoniot relation and entropy condition are proposed to solve the delta shock wave. Moreover, with the limiting viscosity approach, we show all of the existence, uniqueness and stability of solution involving the delta shock wave. The generalized Rankine-Hugoniot relation is also confirmed. Then our theory is successfully applied to two typical systems including the geometric optics equations. Finally, we present the numerical results coinciding with the theoretical analysis.

  6. The distribution of waves in the inner magnetosphere as a function of solar wind parameters

    NASA Astrophysics Data System (ADS)

    Aryan, Homayon; Balikhin, Michael A.; Agapitov, Oleksiy; Krasnoselskikh, Vladimir; Yearby, Keith

    Energetic electrons within the Earth’s radiation belts represent a serious hazard to geostationary satellites. The interactions of electrons with chorus waves play an important role in both the acceleration and loss of radiation belt electrons. Studies of the evolution of energetic electron fluxes rely heavily on numerical codes in order to model energy and pitch angle diffusion due to electron interaction with plasma waves in the frame of quasilinear approximation. Application of these codes requires knowledge of statistical wave models to present wave distributions in the magnetosphere. A number of such models are based on CRESS, Cluster, THEMIS and other mission data. These models present wave distributions as a function of L-shell, magnetic local time, magnetic latitude and geomagnetic activity expressed by geomagnetic indices (Kp or Ae). However, it has been shown by G. Reeves and co-authors that only 50% of geomagnetic storms increase flux of relativistic electrons at GEO while 20% cause a decrease. This emphasizes the importance of including solar wind parameters in addition to geomagnetic indices. The present study examines almost four years (01, January, 2004 to 29, September, 2007) of STAFF (Spatio-Temporal Analysis of Field Fluctuation) data from Double Star TC1 combined with geomagnetic indices and solar wind parameters from OMNI database in order to present a comprehensive model of chorus wave intensities as a function of L-shell, magnetic local time, magnetic latitude, geomagnetic indices and solar wind parameters. The results show that chorus emission is not only sub-storm dependent but also dependent upon solar wind parameters with solar wind velocity evidently the most influential solar wind parameter. The largest peak intensities are observed for lower band chorus during active conditions, high solar wind velocity, low density and high pressure.

  7. Non-dipolar Wilson links for transverse-momentum-dependent wave functions

    E-print Network

    Hsiang-nan Li; Yu-Ming Wang

    2015-06-01

    We propose a new definition of a transverse-momentum-dependent (TMD) wave function with simpler soft subtraction for $k_T$ factorization of hard exclusive processes. The un-subtracted wave function involves two pieces of non-light-like Wilson links oriented in different directions, so that the rapidity singularity appearing in usual $k_T$ factorization is regularized, and the pinched singularity from Wilson-link self-energy corrections is alleviated to a logarithmic one. In particular no soft function is needed, when the two pieces of Wilson links are orthogonal to each other. We show explicitly at one-loop level that the simpler definition with the non-dipolar Wilson links exhibits the same infrared behavior as the one with the dipolar Wilson links and complicated soft subtraction. It is pointed out that both definitions reduce to the naive TMD wave function as the non-light-like Wilson links approach to the light cone. Their equivalence is then extended to all orders by considering the evolution in the Wilson-link rapidity.

  8. Measurement as Absorption of Feynman Trajectories: Collapse of the Wave Function Can be Avoided

    E-print Network

    A. Marchewka; Z. Schuss

    1999-06-21

    We define a measuring device (detector) of the coordinate of quantum particle as an absorbing wall that cuts off the particle's wave function. The wave function in the presence of such detector vanishes on the detector. The trace the absorbed particles leave on the detector is identifies as the absorption current density on the detector. This density is calculated from the solution of Schr\\"odinger's equation with a reflecting boundary at the detector. This current density is not the usual Schr\\"odinger current density. We define the probability distribution of the time of arrival to a detector in terms of the absorption current density. We define coordinate measurement by an absorbing wall in terms of 4 postulates. We postulate, among others, that a quantum particle has a trajectory. In the resulting theory the quantum mechanical collapse of the wave function is replaced with the usual collapse of the probability distribution after observation. Two examples are presented, that of the slit experiment and the slit experiment with absorbing boundaries to measure time of arrival. A calculation is given of the two dimensional probability density function of a free particle from the measurement of the absorption current on two planes.

  9. DYNAMICS AND DAMAGE ASSESSMENT IN IMPACTED CROSS-PLY CFRP PLATE UTILIZING THE WAVEFORM SIMULATION OF LAMB WAVE ACOUSTIC EMISSION

    Microsoft Academic Search

    Y. MIZUTAMI; H. NISHINO; M. TAKEMOTO; K. ONO

    Utilizing the simplex-assisted waveform simulation of the Lamb AE waves, we successfully estimated impact force histories in cross-ply CFRP plates impacted by 10 -43 m\\/s steel ball. The force amplitudes estimated by the waveform simulation are compared with those calculated by energy balance and mass- spring models. The force estimated by the AE waveform simulation appears to represent the most

  10. Comprehensive analysis of the wave function of a hadronic resonance and its compositeness

    E-print Network

    Takayasu Sekihara; Tetsuo Hyodo; Daisuke Jido

    2015-04-07

    We develop a theoretical framework to investigate the two-body composite structure of a resonance as well as a bound state from its wave function. For this purpose, we introduce both one-body bare states and two-body scattering states, and define the compositeness as a fraction of the contribution of the two-body wave function to the normalization of the total wave function. Writing down explicitly the wave function for a resonance state obtained with a general separable interaction, we formulate the compositeness in terms of the position of the resonance pole, the residue of the scattering amplitude at the pole and the derivative of the Green function of the free two-body scattering system. At the same time, our formulation provides the elementariness expressed with the resonance properties and the two-body effective interaction, and confirms the sum rule showing that the summation of the compositeness and elementariness gives unity. In this formulation the Weinberg's relation for the scattering length and effective range can be derived in the weak binding limit. The extension to the resonance states is performed with the Gamow vector, and a relativistic formulation is also established. As its applications, we study the compositeness of the $\\Lambda (1405)$ resonance and the light scalar and vector mesons described with refined amplitudes in coupled-channel models with interactions up to the next to leading order in chiral perturbation theory. We find that $\\Lambda (1405)$ and $f_{0}(980)$ are dominated by the $\\bar{K} N$ and $K \\bar{K}$ composite states, respectively, while the vector mesons $\\rho (770)$ and $K^{\\ast} (892)$ are elementary. We also briefly discuss the compositeness of $N (1535)$ and $\\Lambda (1670)$ obtained in a leading-order chiral unitary approach.

  11. Reliability assessment of different plate theories for elastic wave propagation analysis in functionally graded plates.

    PubMed

    Mehrkash, Milad; Azhari, Mojtaba; Mirdamadi, Hamid Reza

    2014-01-01

    The importance of elastic wave propagation problem in plates arises from the application of ultrasonic elastic waves in non-destructive evaluation of plate-like structures. However, precise study and analysis of acoustic guided waves especially in non-homogeneous waveguides such as functionally graded plates are so complicated that exact elastodynamic methods are rarely employed in practical applications. Thus, the simple approximate plate theories have attracted much interest for the calculation of wave fields in FGM plates. Therefore, in the current research, the classical plate theory (CPT), first-order shear deformation theory (FSDT) and third-order shear deformation theory (TSDT) are used to obtain the transient responses of flexural waves in FGM plates subjected to transverse impulsive loadings. Moreover, comparing the results with those based on a well recognized hybrid numerical method (HNM), we examine the accuracy of the plate theories for several plates of various thicknesses under excitations of different frequencies. The material properties of the plate are assumed to vary across the plate thickness according to a simple power-law distribution in terms of volume fractions of constituents. In all analyses, spatial Fourier transform together with modal analysis are applied to compute displacement responses of the plates. A comparison of the results demonstrates the reliability ranges of the approximate plate theories for elastic wave propagation analysis in FGM plates. Furthermore, based on various examples, it is shown that whenever the plate theories are used within the appropriate ranges of plate thickness and frequency content, solution process in wave number-time domain based on modal analysis approach is not only sufficient but also efficient for finding the transient waveforms in FGM plates. PMID:23714123

  12. Crack detection in a wheel end spindle using wave propagation via modal impacts and piezo actuation

    NASA Astrophysics Data System (ADS)

    Ackers, Spencer; Evans, Ronald; Johnson, Timothy; Kess, Harold; White, Jonathan; Adams, Douglas E.; Brown, Pam

    2006-03-01

    This research demonstrates two methodologies for detecting cracks in a metal spindle housed deep within a vehicle wheel end assembly. First, modal impacts are imposed on the hub of the wheel in the longitudinal direction to produce broadband elastic wave excitation spectra out to 7000 Hz. The response data on the flange is collected using 3000 Hz bandwidth accelerometers. It is shown using frequency response analysis that the crack produces a filter, which amplifies the elastic response of the surrounding components of the wheel assembly. Experiments on wheel assemblies mounted on the vehicle with the vehicle lifted off the ground are performed to demonstrate that the modal impact method can be used to nondestructively evaluate cracks of varying depths despite sources of variability such as the half shaft angular position relative to the non-rotating spindle. Second, an automatic piezo-stack actuator is utilized to excite the wheel hub with a swept sine signal extending from 20 kHz. Accelerometers are then utilized to measure the response on the flange. It is demonstrated using frequency response analysis that the crack filters waves traveling from the hub to the flange. A simple finite element model is used to interpret the experimental results. Challenges discussed include variability from assembly to assembly, the variability in each assembly, and the high amount of damping present in each assembly due to the transmission gearing, lubricant, and other components in the wheel end. A two-channel measurement system with a graphical user interface for detecting cracks was also developed and a procedure was created to ensure that operators properly perform the test.

  13. The impact of heat, cold, and heat waves on hospital admissions in eight cities in Korea

    NASA Astrophysics Data System (ADS)

    Son, Ji-Young; Bell, Michelle L.; Lee, Jong-Tae

    2014-01-01

    Although the impact of temperature on mortality is well documented, relatively fewer studies have evaluated the associations of temperature with morbidity outcomes such as hospital admissions, and most studies were conducted in North America or Europe. We evaluated weather and hospital admissions including specific causes (allergic disease, asthma, selected respiratory disease, and cardiovascular disease) in eight major cities in Korea from 2003 to 2008. We also explored potential effect modification by individual characteristics such as sex and age. We used hierarchical modeling to first estimate city-specific associations between heat, cold, or heat waves and hospitalizations, and then estimated overall effects. Stratified analyses were performed by cause of hospitalization, sex, and age (0-14, 15-64, 65-74, and ?75 years). Cardiovascular hospitalizations were significantly associated with high temperature, whereas hospitalizations for allergic disease, asthma, and selected respiratory disease were significantly associated with low temperature. The overall heat effect for cardiovascular hospitalization was a 4.5 % (95 % confidence interval 0.7, 8.5 %) increase in risk comparing hospitalizations at 25 to 15 °C. For cold effect, the overall increase in risk of hospitalizations comparing 2 with 15 °C was 50.5 (13.7, 99.2 %), 43.6 (8.9, 89.5 %), and 53.6 % (9.8, 114.9 %) for allergic disease, asthma, and selected respiratory disease, respectively. We did not find statistically significant effects of heat waves compared with nonheat wave days. Our results suggest susceptible populations such as women and younger persons. Our findings provide suggestive evidence that both high and low ambient temperatures are associated with the risk of hospital admissions, particularly in women or younger person, in Korea.

  14. On the Origin of d-WAVE Pair Functions in HIGH-Tc Superconductivity

    NASA Astrophysics Data System (ADS)

    Mattis, Daniel C.

    We argue that the usual Hubbard's model produces only s-wave pairing functions and, even then, only at unphysically large values of the lumped parameter J?4t2/U. It follows that a reliable theory of high-Tc superconductivity has to include additional features if it is to reproduce the d-wave gap. We test the effects of an alternating potential caused by a charge stripe, on the ground state of the Hubbard model in strong-coupling. If we "fine tune" we do find the d-waves. However, a better-formulated version of a three-band model yields a sturdier theory of pair formation in high-Tc superconductivity. The coupling constant g1=t2/V factors out, hence it serves only to establish the unit of energy; the underlying Hamiltonian is universal. We outline the principal properties of this model, including the intimate relation between charge-density stripes and the d-wave pair function, its rejection of 45° stripes (checkerboard pattern), and other concerns.

  15. The Impact of Stratospheric Ozone Changes on Downward Wave Coupling in the Southern Hemisphere*

    E-print Network

    Harnik, Nili

    (MERRA) dataset, wave coupling in the model maximizes during October­November when there is a bounded wave geometry configuration. However, the wave coupling in the model is stronger than in the MERRA

  16. The Hartle-Hawking wave function in 2d causal set quantum gravity

    E-print Network

    Lisa Glaser; Sumati Surya

    2015-07-02

    We define the Hartle-Hawking no-boundary wave function for causal set theory (CST) over the discrete analogs of spacelike hypersurfaces. Using Markov Chain Monte Carlo and numerical integration methods we analyse the wave function in non- perturbative 2d CST. We find that in the low temperature regime it is dominated by causal sets which have no continuum counterparts but possess physically interesting geometric properties. Not only do they exhibit a rapid spatial expansion with respect to the discrete proper time but also a high degree of spatial homogeneity. The latter is due to the extensive overlap of the causal pasts of the elements in the final discrete hypersurface and corresponds to high graph connectivity. Our results thus suggest new possibilities for the role of quantum gravity in the observable universe.

  17. Wave-function renormalization constant for the one-band Hubbard Hamiltonian in two dimensions

    SciTech Connect

    Louis, E.; Chiappe, G. (Departamento de Fisica Aplicada, Universidad de Alicante, Apartado 99, E-03080 Alicante (Spain)); Galan, J.; Guinea, F.; Verges, J.A. (Instituto de Ciencia de Materiales (Consejo Superior de Investigaciones Cientificas), Universidad Autonom, de Madrid ( ) E-28049 Madrid (Spain))

    1993-07-01

    The wave-function renormalization constant [ital Z] has been calculated for the one-band Hubbard model on a square lattice. Near half-filling the Hamiltonian has been solved on finite clusters (up to 16[times]16) by means of the unrestricted Hartree-Fock (UHF) approximation. Some checks of the UHF results have been made on 4[times]4 clusters by means of the Lanczos method for [ital U]=[infinity]. At high dilutions (two electrons) exact calculations have been carried out. The ground-state wave functions and energies for the different cases here considered are discussed. The system shows nonconventional behavior ([ital Z]=0) near half-filling. For a given value of [ital U], [ital Z] vanishes at low dopings, and becomes finite as doping is increased. For very large [ital U] the value of [ital Z] remains finite for all dopings, excluding half-filling. These results are cast into a plausible phase diagram.

  18. A First-Landau-Level Laughlin/Jain Wave Function for the Fractional Quantum Hall Effect

    E-print Network

    Joe Ginocchio; Wick Haxton

    1996-04-11

    We show that the introduction of a more general closed-shell operator allows one to extend Laughlin's wave function to account for the richer hierarchies (1/3, 2/5, 3/7 ...; 1/5, 2/9, 3/13, ..., etc.) found experimentally. The construction identifies the special hierarchy states with condensates of correlated electron clusters. This clustering implies a single-particle (ls)j algebra within the first Landau level (LL) identical to that of multiply filled LLs in the integer quantum Hall effect. The end result is a simple generalized wave function that reproduces the results of both Laughlin and Jain, without reference to higher LLs or projection.

  19. Calculations of properties of screened He-like systems using correlated wave functions.

    PubMed

    Dai, S T; Solovyova, A; Winkler, P

    2001-07-01

    The purpose of the present study is twofold. First, the techniques of correlated wave functions for two-electron systems have been extended to obtain results for P and D states in a screening environment, and in particular for Debye screening. In these calculations, the satisfaction of both the quantum virial theorem and a related sum rule has been enforced and found to provide a high degree of stability of the solutions. Second, in order to facilitate the general use of correlated wave functions in combination with sum rule stability criteria, a rather systematic computational approach to this notoriously cumbersome method has been developed and thoroughly discussed here. Accurate calculations for few-electron systems are of interest to plasma diagnostics; in particular, when inaccuracies in binding energies are drastically magnified as they occur in exponents of Boltzmann factors. PMID:11461411

  20. Measurements of ocean wave spectra and modulation transfer function with the airborne two frequency scatterometer

    NASA Technical Reports Server (NTRS)

    Weissman, D. E.; Johnson, J. W.

    1984-01-01

    The directional spectrum and the microwave modulation transfer function of ocean waves can be measured with the airborne two frequency scatterometer technique. Similar to tower based observations, the aircraft measurements of the Modulation Transfer Function (MTF) show that it is strongly affected by both wind speed and sea state. Also detected are small differences in the magnitudes of the MTF between downwind and upwind radar look directions, and variations with ocean wavenumber. The MTF inferred from the two frequency radar is larger than that measured using single frequency, wave orbital velocity techniques such as tower based radars or ROWS measurements from low altitude aircraft. Possible reasons for this are discussed. The ability to measure the ocean directional spectrum with the two frequency scatterometer, with supporting MTF data, is demonstrated.

  1. Wave functions of the Q .Q interaction in terms of unitary 9-j coefficients

    NASA Astrophysics Data System (ADS)

    Zamick, Larry; Harper, Matthew

    2015-03-01

    We obtain wave functions for two protons and two neutrons in the g9 /2 shell expressed as column vectors with amplitudes D (Jp,Jn) . When we use a quadrupole-quadrupole interaction (Q .Q ) we get, in many cases, a very strong overlap with wave functions given by a single set of unitary 9-j coefficients—U 9 j =<(jj ) 2 j(jjJB|(jj ) Jp(jj ) Jn) I> . Here JB=9 for even I T =0 states. For both even and odd T =1 states we take JB equal to 8 whilst for odd I ,T =0 we take JB to be 7. We compare the Q .Q results with those of a more realistic interaction.

  2. Measurements of ocean wave spectra and modulation transfer function with the airborne two-frequency scatterometer

    NASA Technical Reports Server (NTRS)

    Weissman, D. E.; Johnson, J. W.

    1986-01-01

    The directional spectrum and the microwave modulation transfer function of ocean waves can be measured with the airborne two frequency scatterometer technique. Similar to tower based observations, the aircraft measurements of the Modulation Transfer Function (MTF) show that it is strongly affected by both wind speed and sea state. Also detected are small differences in the magnitudes of the MTF between downwind and upwind radar look directions, and variations with ocean wavenumber. The MTF inferred from the two frequency radar is larger than that measured using single frequency, wave orbital velocity techniques such as tower based radars or ROWS measurements from low altitude aircraft. Possible reasons for this are discussed. The ability to measure the ocean directional spectrum with the two frequency scatterometer, with supporting MTF data, is demonstrated.

  3. Wave function for spontaneous parametric down-conversion with orbital angular momentum

    SciTech Connect

    Barbosa, Geraldo A. [Department of Electrical Engineering and Computer Science, Northwestern University, 2145 N. Sheridan Road, Evanston, Illinois 60208-3118 (United States)

    2009-12-15

    Several wave-function approximations describing spontaneous parametric down-conversion can be found in the literature. Basically all cases are derived from the standard Hamiltonian for parametric down-conversion. Most frequently, particular cases describing collinear or paraxial approximations are described. This work presents a wave function in compact form, valid for all cases of single photon-pair conversion (Type I or Type II), for all angles allowed by the phase-matching conditions and for all orbital angular momentum values l. Examples are given of coincidence structures to be expected for signal and idler photons. Partial transfer of orbital angular momentum from the pump laser to the photon pair is discussed. Some hypothesis for the decay channels of the nontransferred part of the orbital angular momentum is made.

  4. Form Factors and Wave Functions of Vector Mesons in Holographic QCD

    SciTech Connect

    Hovhannes R. Grigoryan; Anatoly V. Radyushkin

    2007-07-01

    Within the framework of a holographic dual model of QCD, we develop a formalism for calculating form factors of vector mesons. We show that the holographic bound states can be described not only in terms of eigenfunctions of the equation of motion, but also in terms of conjugate wave functions that are close analogues of quantum-mechanical bound state wave functions. We derive a generalized VMD representation for form factors, and find a very specific VMD pattern, in which form factors are essentially given by contributions due to the first two bound states in the Q^2-channel. We calculate electric radius of the \\rho-meson, finding the value < r_\\rho^2>_C = 0.53 fm^2.

  5. Supercritical electric dipole and migration of electron wave function in graphene

    E-print Network

    Gorbar, E V; Sobol, O O

    2015-01-01

    We study the Dirac equation for quasiparticles in gapped graphene with two oppositely charged impurities by using the technique of linear combination of atomic orbitals and variational Galerkin--Kantorovich method. We show that for sufficiently large charges of impurities the wave function of the occupied electron bound state of the highest energy changes its localization from the negatively charged impurity to the positively charged one as the distance between the impurities increases. This migration of the electron wave function of supercritical electric dipole is a generalization of the familiar phenomenon of the atomic collapse of single charged impurity to the case where electron-hole pairs are spontaneously created from vacuum in bound states with charge impurities thus partially screening them.

  6. Supercritical electric dipole and migration of electron wave function in graphene

    E-print Network

    E. V. Gorbar; V. P. Gusynin; O. O. Sobol

    2015-06-28

    We study the Dirac equation for quasiparticles in gapped graphene with two oppositely charged impurities by using the technique of linear combination of atomic orbitals and variational Galerkin--Kantorovich method. We show that for sufficiently large charges of impurities the wave function of the occupied electron bound state of the highest energy changes its localization from the negatively charged impurity to the positively charged one as the distance between the impurities increases. This migration of the electron wave function of supercritical electric dipole is a generalization of the familiar phenomenon of the atomic collapse of single charged impurity to the case where electron-hole pairs are spontaneously created from vacuum in bound states with charge impurities thus partially screening them.

  7. The robustness of the vacuum wave function and other matters for Yang-Mills theory

    E-print Network

    Dimitra Karabali; V. P. Nair

    2007-05-21

    In the first part of this paper, we present a set of simple arguments to show that the two-dimensional gauge anomaly and the (2+1)-dimensional Lorentz symmetry determine the leading Gaussian term in the vacuum wave function of (2+1)-dimensional Yang-Mills theory. This is to highlight the robustness of the wave function and its relative insensitivity to the choice of regularizations. We then comment on the correspondence with the explicit calculations done in earlier papers. We also make some comments on the nature of the gauge-invariant configuration space for Euclidean three-dimensional gauge fields (relevant to (3+1)-dimensional Yang-Mills theory).

  8. Energy-Level and Wave-Function Statistics in the Anderson Model of Localization

    Microsoft Academic Search

    Bernhard Mehlig; Michael Schreiber

    Universal aspects of correlations in the spectra and wave functions of closed, complex quantum systems can be described by\\u000a random-matrix theory (RMT) [1]. On small energy scales, for example, the eigenvalues, eigenfunctions and matrix elements of\\u000a disordered quantum systems in the metallic regime [2] or those of classically chaotic quantum systems [3] exhibit universal\\u000a statistical properties very well described by

  9. Feshbach-like study of He resonant states in Debye plasmas using explicitly correlated wave functions

    NASA Astrophysics Data System (ADS)

    Cardona, J. C.; Ordoñez, A. F.; Sanz-Vicario, J. L.

    2012-11-01

    We present a study on the 1,3Se, 1,3P° and 1,3 De He resonant states below the He+ (N = 2) threshold under the influence of a plasma environment, when the Debye screening length is varied. The interaction between all charged particles is modeled with Yukawa-like screened Coulomb potentials. We make use of the Feshbach projector method to characterize resonant states, implemented by using explicitly correlated CI-wave functions.

  10. Determination of quark-antiquark component of the photon wave function for u, d, s quarks

    NASA Astrophysics Data System (ADS)

    Anisovich, A. V.; Anisovich, V. V.; Dakhno, L. G.; Nikonov, V. A.; Sarantsev, A. V.

    2005-11-01

    Based on the data for the transitions pi0, eta, eta' -> gamma gamma^*(Q^2) and reactions of the e^+ e^- -annihilations, e^+ e^- -> rho0, omega, phi and e^+ e^--> hadrons at 1wave function gamma^*(Q^2) -> q anti-q (q= u, d, s) for the region 0< Q^2 <1 (GeV/c)^2.

  11. Photon wave function in nonforward diffractive scattering with nonvanishing quark masses

    NASA Astrophysics Data System (ADS)

    Gieseke, S.; Qiao, Cong-Feng

    2000-04-01

    The light-cone photon wave function in explicit helicity states, valid for massive quarks and in both momentum and configuration space, is presented by considering leading order photon-proton hard scattering; i.e., the splitting quark pair scatters with the proton in the Regge limit. Further we apply it to the diffractive scattering at a nonzero momentum transfer and reach a similar factorization as in the case of zero momentum transfer.

  12. Wien2wannier: From linearized augmented plane waves to maximally localized Wannier functions

    NASA Astrophysics Data System (ADS)

    Kuneš, Jan; Arita, Ryotaro; Wissgott, Philipp; Toschi, Alessandro; Ikeda, Hiroaki; Held, Karsten

    2010-11-01

    We present an implementation of an interface between the full-potential linearized augmented plane wave package Wien2k and the wannier90 code for the construction of maximally localized Wannier functions. The FORTRAN code and a documentation is made available and results are discussed for SrVO 3, Sr 2IrO 4 (including spin-orbit coupling), LaFeAsO, and FeSb 2.

  13. Wien2wannier: From linearized augmented plane waves to maximally localized Wannier functions

    Microsoft Academic Search

    Jan Kunes; Ryotaro Arita; Philipp Wissgott; Alessandro Toschi; Hiroaki Ikeda; Karsten Held

    2010-01-01

    We present an implementaion of interface between the full-potential\\u000alinearized augmented plane wave package Wien2k and the wannier90 code for the\\u000aconstruction of maximally localized Wannier functions. The FORTRAN code and a\\u000adocumentation is made available and results are discussed for SrVO$_3$,\\u000aSr$_2$IrO$_4$ (including spin-orbit coupling), LaFeAsO, and FeSb$_2$.

  14. Phase diagram of the Hubbard model: A variational wave-function approach

    SciTech Connect

    Coppersmith, S. N.; Yu, C. C.

    1989-06-01

    We explore the phase diagram of the Hubbard model by generalizing the Gutzwiller variational wave function to take into account nearest-neighbor spin correlations. The energies of various variational states are calculated and compared. At half filling the lowest energy state has long-range antiferromagnetic correlations, in agreement with previous results. Away from half filling, when the antiferromagnet no longer has the lowest energy, the Gutzwiller approximation yields a lower energy than that found for small spin polarons.

  15. Closed Bosonic String Partition Function in Time Independent Exact PP-Wave Background

    Microsoft Academic Search

    Agapitos Hatzinikitas; Ioannis Smyrnakis

    2003-01-01

    The modular invariance of the one-loop partition function of the closed\\u000abosonic string in four dimensions in the presence of certain homogeneous exact\\u000app-wave backgrounds is studied. In the absence of an axion field the partition\\u000afunction is found to be modular invariant. In the presence of an axion field\\u000amodular invariace is broken. This can be attributed to the

  16. Combining two-body density correlation functionals with multiconfigurational wave functions using natural orbitals and occupation numbers.

    PubMed

    Pérez-Jiménez, Angel J; Pérez-Jordá, José M; Sancho-García, Juan C

    2007-09-14

    We propose a procedure that combines multiconfigurational (MC) wave functions with two-body density correlation functionals by transforming the latter into functionals of the MC natural orbitals and occupation numbers. The method is tested with the spectroscopic constants of a set of 11 diatomics, the diradical-involved automerization barrier of cyclobutadiene, the energy difference between triplet and open-shell singlet states in He and the methylene molecule, and the magnetic coupling constants of several systems, such as NiO, KNiF(3), K(2)NiF(4), La(2)CuO(4), alpha-4-dehydrotoluene, 1,1('),5,5(')-tetramethyl-6,6(')-dioxo-3,3(')-biverdazyl, [Cu(2)Cl(6)](-2), copper(II) acetate monohidrate and H-He-H. The procedure is applied to the Colle-Salvetti [Theor. Chim. Acta 37, 329 (1975); 53, 55 (1979)], functional and to a size-consistent functional depending on the on-top pair density (F1-5-N(eff)). On average, the best results are provided by the transformed F1-5-N(eff) [J. Chem. Phys. 114, 2022 (2001)] functional. PMID:17867732

  17. Combining two-body density correlation functionals with multiconfigurational wave functions using natural orbitals and occupation numbers

    NASA Astrophysics Data System (ADS)

    Pérez-Jiménez, Ángel J.; Pérez-Jordá, José M.; Sancho-García, Juan C.

    2007-09-01

    We propose a procedure that combines multiconfigurational (MC) wave functions with two-body density correlation functionals by transforming the latter into functionals of the MC natural orbitals and occupation numbers. The method is tested with the spectroscopic constants of a set of 11 diatomics, the diradical-involved automerization barrier of cyclobutadiene, the energy difference between triplet and open-shell singlet states in He and the methylene molecule, and the magnetic coupling constants of several systems, such as NiO, KNiF3, K2NiF4, La2CuO4, ?-4-dehydrotoluene, 1,1',5,5'-tetramethyl-6,6'-dioxo-3,3'-biverdazyl, [Cu2Cl6]-2, copper(II) acetate monohidrate and H-He-H. The procedure is applied to the Colle-Salvetti [Theor. Chim. Acta 37, 329 (1975); 53, 55 (1979)], functional and to a size-consistent functional depending on the on-top pair density (F1-5-Neff). On average, the best results are provided by the transformed F1-5-Neff [J. Chem. Phys. 114, 2022 (2001)] functional.

  18. Impact of the intraseasonal Kelvin wave on the regional circulation of the Humboldt system: the idealized case

    Microsoft Academic Search

    B. Dewitte; S. Thual; V. Echevin; S. Purca

    2009-01-01

    The equatorial Kelvin wave exhibits a significant variability at intraseasonal timescales. This variability is also apparently modulated at interannual to decadal timescales as revealed by the SODA oceanic Reanalysis, which could have a large impact on the regional circulation off Peru and Chile. Here a linear ocean equatorial model is used to force the ROMS (Regional Ocean Modelling System) eddy-resolving

  19. Signal wave generator signals recorded by the Federal Outdoor Impact Laboratory's on-board Data Acquisition System

    Microsoft Academic Search

    C. Brown; B. Liu

    1994-01-01

    The document contains signal wave generator signals recorded by the data acquisition system (DAS) used by the Federal Highway Administration's Federal Outdoor Impact Laboratory (FOIL) located at the Turner-Fairbank Highway Research Center (TFHRC) in McLean, Virginia. The FOIL Test Director and Junior Engineer performed the evaluation testing on September 29, 1993. The Contracting Officer's Technical Representative (COTR) supervised the project.

  20. Waves

    E-print Network

    LaCure, Mari Mae

    2010-04-29

    travel as waves through space and time. Waves can also manifest visibly through other mediums, water for example, as they travel outward from where an object disturbs the surface. As the title of my thesis exhibit, Waves refers to my aim to imbue.... As a viewer approaches a drawing from different angles the light reflected by the image subtly changes intensity. 4 Sewing by hand further adds dimension where it is seen in the front, and creates a shadow where it can be seen through the back...

  1. The impact of wave exposure on the meiofauna of Gelidium pristoides (Turner) Kuetzing (Gelidiales: Rhodophyta)

    NASA Astrophysics Data System (ADS)

    Gibbons, M. J.

    1988-12-01

    The impact of wave exposure on the meiofaunal communities colonising Gelidium pristoides, was examined on five shores around False Bay, South Africa. Under conditions of constant algal structure and mass, and in tufts with similar epiphyte and sediment loads, exposure had a profound impact on meiofaunal communities. Algae on sheltered shores supported significantly greater numbers of animals in the size range 63-280 ?m (predominantly copepods, copepod nauplii and ostracods), while those on exposed shores supported a greater number of amphipods and bivalves. Total meiofaunal biomass per tuft remained constant irrespective of shore type. Differences between shores are discussed in terms of algal structure and animal size and morphology. Gelidium tufts are open-plan and offer little resistance to water movement; as the frond diameter is wider than the meiofauna are long, small animals are likely to be flushed more easily from exposed than sheltered shores. Differences in the abundance of permanent meiofauna between shores may, however, reflect ifferences in the organic content of sediments, although this was not examined. It is also suggested that meiofaunal communities on plants from different shores are influenced by the total algal and macrofaunal standing stocks, which act as banks of meiofauna and influence the regularity and magnitude of immigration. Extrapolating these data to the whole shore indicates that while the biomass of meiofauna may be greater on exposed than sheltered shores, the proportional contribution of meiofauna to total secondary production is greater under more sheltered conditions.

  2. Emergence of complex and spinor wave functions in scale relativity. I. Nature of scale variables

    NASA Astrophysics Data System (ADS)

    Nottale, Laurent; Célérier, Marie-Noëlle

    2013-11-01

    One of the main results of scale relativity as regards the foundation of quantum mechanics is its explanation of the origin of the complex nature of the wave function. The scale relativity theory introduces an explicit dependence of physical quantities on scale variables, founding itself on the theorem according to which a continuous and non-differentiable space-time is fractal (i.e., scale-divergent). In the present paper, the nature of the scale variables and their relations to resolutions and differential elements are specified in the non-relativistic case (fractal space). We show that, owing to the scale-dependence which it induces, non-differentiability involves a fundamental two-valuedness of the mean derivatives. Since, in the scale relativity framework, the wave function is a manifestation of the velocity field of fractal space-time geodesics, the two-valuedness of velocities leads to write them in terms of complex numbers, and yields therefore the complex nature of the wave function, from which the usual expression of the Schrödinger equation can be derived.

  3. On the Nature of the Change in the Wave Function in a Measurement in Quantum Mechanics

    E-print Network

    Douglas M. Snyder

    2003-04-06

    Generally a central role has been assigned to an unavoidable physical interaction between the measuring instrument and the physical entity measured in the change in the wave function that often occurs in measurement in quantum mechanics. A survey of textbooks on quantum mechanics by authors such as Dicke and Witke (1960), Eisberg and Resnick (1985), Gasiorowicz (1974), Goswami (1992), and Liboff (1993) supports this point. Furthermore, in line with the view of Bohr and Feynman, generally the unavoidable interaction between a measuring instrument and the physical entity measured is considered responsible for the uncertainty principle. A gedankenexperiment using Feynman's double-hole interference scenario shows that physical interaction is not necessary to effect the change in the wave function that occurs in measurement in quantum mechanics. Instead, the general case is that knowledge is linked to the change in the wave function, not a physical interaction between the physical existent measured and the measuring instrument. Empirical work on electron shelving that involves null measurements, or what Renninger called negative observations (Zeitschrift fur Physik, vol. 158, p. 417), supports these points. Work on electron shelving is reported by Dehmelt and his colleagues (Physical Review Letters, vol. 56, p. 2797), Wineland and his colleagues (Physical Review Letters, vol. 57, p. 1699), and Sauter, Neuhauser, Blatt, and Toschek (Physical Review Letters, vol. 57, p. 1696).

  4. Computing wave functions of nonlinear Schrödinger equations: A time-independent approach

    NASA Astrophysics Data System (ADS)

    Chang, S.-L.; Chien, C.-S.; Jeng, B.-W.

    2007-09-01

    We present a novel algorithm for computing the ground-state and excited-state solutions of M-coupled nonlinear Schrödinger equations (MCNLS). First we transform the MCNLS to the stationary state ones by using separation of variables. The energy level of a quantum particle governed by the Schrödinger eigenvalue problem (SEP) is used as an initial guess to computing their counterpart of a nonlinear Schrödinger equation (NLS). We discretize the system via centered difference approximations. A predictor-corrector continuation method is exploited as an iterative method to trace solution curves and surfaces of the MCNLS, where the chemical potentials are treated as continuation parameters. The wave functions can be easily obtained whenever the solution manifolds are numerically traced. The proposed algorithm has the advantage that it is unnecessary to discretize or integrate the partial derivatives of wave functions. Moreover, the wave functions can be computed for any time scale. Numerical results on the ground-state and excited-state solutions are reported, where the physical properties of the system such as isotropic and nonisotropic trapping potentials, mass conservation constraints, and strong and weak repulsive interactions are considered in our numerical experiments.

  5. Emergence of complex and spinor wave functions in scale relativity. I. Nature of scale variables

    SciTech Connect

    Nottale, Laurent; Célérier, Marie-Noëlle [LUTH, Observatoire de Paris, CNRS, Université Paris-Diderot, 5 place Jules Janssen, 92195 Meudon Cedex (France)] [LUTH, Observatoire de Paris, CNRS, Université Paris-Diderot, 5 place Jules Janssen, 92195 Meudon Cedex (France)

    2013-11-15

    One of the main results of scale relativity as regards the foundation of quantum mechanics is its explanation of the origin of the complex nature of the wave function. The scale relativity theory introduces an explicit dependence of physical quantities on scale variables, founding itself on the theorem according to which a continuous and non-differentiable space-time is fractal (i.e., scale-divergent). In the present paper, the nature of the scale variables and their relations to resolutions and differential elements are specified in the non-relativistic case (fractal space). We show that, owing to the scale-dependence which it induces, non-differentiability involves a fundamental two-valuedness of the mean derivatives. Since, in the scale relativity framework, the wave function is a manifestation of the velocity field of fractal space-time geodesics, the two-valuedness of velocities leads to write them in terms of complex numbers, and yields therefore the complex nature of the wave function, from which the usual expression of the Schrödinger equation can be derived.

  6. Towards the explicit computation of Bohm velocities associated to N-electron wave-functions with arbitrary spin-orientations

    E-print Network

    A. Alarcon; X. Cartoixa; X. Oriols

    2014-08-19

    The direct solution of the many-particle Schr\\"odinger equation is computationally inaccessible for more than very few electrons. In order to surpass this limitation, one of the authors [X. Oriols, Phys. Rev. Lett. 2007, 98 (066803)] has recently proposed a new model to study electron-electron correlations from Bohm trajectories associated to time-dependent wave-packets solutions of pseudo single-particle Schr\\"odinger equations. In the aforementioned paper only the orbital exchange interaction is considered assuming that all electrons have the same spin orientation. Then, the many-particle wave function is a complex Slater determinant of the single-particle wave-packets. In the present work the previous formalism is extended to study many-particle wave functions where the electrons have different spin orientations.The main difficulty to treat N different electron spin orientations with time-dependent wave-packets is that one must study all the possible N!N! products of permutations among spin states. To overcome this computationally inaccessible problem, in this article the total wave function is treated as a separated product of two many-particle wave functions, the first with spin up and the second with spin down. In order to numerically justify this approximation, the Bohm velocity in different antisymmetric total wave-function scenarios is computed. The computational results confirms the accurate validity of our approximation under a large number of cases.

  7. Asymptotic formula for the condensate wave function of a trapped Bose gas

    SciTech Connect

    Margetis, Dionisios [Gordon McKay Laboratory, Harvard University, Cambridge, Massachusetts 02138-2901 (United States)] [Gordon McKay Laboratory, Harvard University, Cambridge, Massachusetts 02138-2901 (United States)

    2000-05-01

    An analytical property is pointed out for the universal differential equation first derived by Dalfovo, Pitaevskii, and Stringari for the condensate wave function at the boundary of a trapped Bose gas. Specifically, the constant multiplying the Airy function of the solution asymptotically outside the trap is {radical}(2). Accordingly, the Wentzel-Kramers-Brillouin approximation is determined in the case of a spherically symmetric harmonic potential. This calculation is related to Josephson-type currents flowing between well-separated traps. (c) 2000 The American Physical Society.

  8. Synoptic-scale variability of arctic gravity wave activity during summer and potential impacts on the high latitude middle atmosphere

    NASA Astrophysics Data System (ADS)

    Gerrard, Andrew John

    Although the role of gravity waves in the global atmospheric circulation is generally understood, discussion of synoptic gravity wave activity, especially pertaining to high latitude summer environments, is lacking in the literature. Tropospherically generated gravity waves greatly contribute to the zonal drag necessary to induce meridional outflow and subsequent upwelling observed in the adiabatically cooled summer mesosphere, ultimately resulting in an environment conducive to mesospheric cloud formation. However, the very gravity wave activity responsible for this induced cooling is also believed to be a major source of variability on mesospheric clouds over shorter time scales, and this topic should be of considerable interest if such clouds are to be used as tracers of the global climate. It is therefore the purpose of this thesis to explore high latitude synoptic gravity wave activity and ultimately seek an understanding of the associated influence on overlaying summer mesospheric clouds. Another goal is to better understand and account for potential variability in high latitude middle and upper atmospheric measurements that can be directly associated with "weather conditions" at lower altitudes. These endeavors are addressed through Rayleigh/aerosol lidar data obtained from the ARCtic LIdar TEchnology (ARCLITE) facility located at Sondrestrom, Greenland (67°N, 310°E), global tropospheric and stratospheric analyses and forecasts, and the Gravity-wave Regional Or Global RAy Tracer (GROGRAT) model. In this study we are able to show that (a) the upper stratospheric gravity wave strength and the brightness of overlaying mesospheric clouds, as measured by representative field proxies, are negatively correlated over time scales of less than a day, (b) such upper stratospheric gravity wave variability is inversely related to mesospheric cloud variability on time scales of ˜1 to 4 hours, (c) gravity wave hindcasts faithfully reproduce experimental lidar observations taken over the month of August 1996, (d) the observed upper stratospheric gravity wave activity is shown to originate from regionalized, non-orographic sources in the troposphere, (e) such gravity wave activity can propagate through the middle atmosphere, potentially impacting overlaying mesospheric clouds, and (f) the forecasting of such upper stratospheric gravity wave activity, and therefore the corresponding mesospheric cloud activity, is feasible. In conclusion, the results herein provide additional evidence of gravity wave influence on mesospheric clouds, a step towards the forecasting of regional gravity wave activity, and ultimately a better understanding of synoptic gravity wave activity at high latitudes.

  9. Fragment-based configuration interaction wave function to calculate environmental effect on excited states in proteins and solutions

    NASA Astrophysics Data System (ADS)

    Hasegawa, Jun-ya

    2013-05-01

    Solvatochromic effect in proteins and solutions was described by a configuration interaction singles (CIS) wave function with fragment-localized molecular orbitals. Coarse-grained analysis indicated that the CI wave function can be described by local excitations and charge-transfer (CT) excitations between the chromophore and the environment. We developed an atomic-orbital direct runcated CIS code and applied the excited states of retinal chromophore in bacteriorhodopsin and MeOH environments, and those of s-trans-acrolein in water. Number of excitation operators was significantly reduced by eliminating the CT excitations between the environmental fragments. The truncated CIS wave functions reproduced the original excitation energies very well.

  10. Characterization of a Setup to test the Impact of High-Amplitude Pressure Waves on Living Cells

    NASA Astrophysics Data System (ADS)

    Schmidt, Mischa; Kahlert, Ulf; Wessolleck, Johanna; Maciaczyk, Donata; Merkt, Benjamin; Maciaczyk, Jaroslaw; Osterholz, Jens; Nikkhah, Guido; Steinhauser, Martin O.

    2014-01-01

    The impact of pressure waves on cells may provide several possible applications in biology and medicine including the direct killing of tumors, drug delivery or gene transfection. In this study we characterize the physical properties of mechanical pressure waves generated by a nanosecond laser pulse in a setup with well-defined cell culture conditions. To systematically characterize the system on the relevant length and time scales (micrometers and nanoseconds) we use photon Doppler velocimetry (PDV) and obtain velocity profiles of the cell culture vessel at the passage of the pressure wave. These profiles serve as input for numerical pressure wave simulations that help to further quantify the pressure conditions on the cellular length scale. On the biological level we demonstrate killing of glioblastoma cells and quantify experimentally the pressure threshold for cell destruction.

  11. On the longitudinal response function of interferometers for massive gravitational waves from a bimetric theory of gravity

    E-print Network

    Christian Corda

    2008-08-26

    Recently, some papers in the literature have shown that, from a bimetric theory of gravity, it is possible to produce massive gravitational waves which generate a longitudinal component in a particular polarization of the wave. After a review of previous works, in this paper the longitudinal response function of interferometers for this particular polarization of the wave is computed in two different gauges, showing the gauge invariance, and in its full frequency dependence, with specific application to the Virgo and LIGO interferometers.

  12. The wave function and minimum uncertainty function of the bound quadratic Hamiltonian system

    NASA Technical Reports Server (NTRS)

    Yeon, Kyu Hwang; Um, Chung IN; George, T. F.

    1994-01-01

    The bound quadratic Hamiltonian system is analyzed explicitly on the basis of quantum mechanics. We have derived the invariant quantity with an auxiliary equation as the classical equation of motion. With the use of this invariant it can be determined whether or not the system is bound. In bound system we have evaluated the exact eigenfunction and minimum uncertainty function through unitary transformation.

  13. Impact Assessment Summary 1. Name of policy, function or service.

    E-print Network

    planning. 4. Information and Data (evidence) used. Consultation has been undertaken with a variety. Additionally, information from a range of external sources has been obtained. 5. Summary of Impact as the driver is to reduce age discrimination in the workforce. Additionally, women who may have had career

  14. Convergence of many-body wave-function expansions using a plane-wave basis: From homogeneous electron gas to solid state systems

    NASA Astrophysics Data System (ADS)

    Shepherd, James J.; Grüneis, Andreas; Booth, George H.; Kresse, Georg; Alavi, Ali

    2012-07-01

    Using the finite simulation-cell homogeneous electron gas (HEG) as a model, we investigate the convergence of the correlation energy to the complete-basis-set (CBS) limit in methods utilizing plane-wave wave-function expansions. Simple analytic and numerical results from second-order Møller-Plesset theory (MP2) suggest a 1/M decay of the basis-set incompleteness error where M is the number of plane waves used in the calculation, allowing for straightforward extrapolation to the CBS limit. As we shall show, the choice of basis-set truncation when constructing many-electron wave functions is far from obvious, and here we propose several alternatives based on the momentum transfer vector, which greatly improve the rate of convergence. This is demonstrated for a variety of wave-function methods, from MP2 to coupled-cluster doubles theory and the random-phase approximation plus second-order screened exchange. Finite basis-set energies are presented for these methods and compared with exact benchmarks. A transformation can map the orbitals of a general solid state system onto the HEG plane-wave basis and thereby allow application of these methods to more realistic physical problems. We demonstrate this explicitly for solid and molecular lithium hydride.

  15. Computation of the Drift Velocity of Spiral Waves using Response Functions I.V. Biktasheva and A.J. Foulkes

    E-print Network

    Biktashev, Vadim N.

    wave rotation frequency, and spatial drift, that is slow movement of the spiral's rotation centre'' drift caused by (approx­ imately) periodic modulation of medium properties through external forcing [20Computation of the Drift Velocity of Spiral Waves using Response Functions I.V. Biktasheva and A

  16. Computation of the Drift Velocity of Spiral Waves using Response Functions I.V. Biktasheva and A.J. Foulkes

    E-print Network

    Biktashev, Vadim N.

    wave rotation frequency, and spatial drift, that is slow movement of the spiral's rotation centre" drift caused by (approx- imately) periodic modulation of medium properties through external forcing [20Computation of the Drift Velocity of Spiral Waves using Response Functions I.V. Biktasheva and A

  17. On de Broglie's soliton wave function of many particles with finite masses, energies and momenta

    E-print Network

    Agung Budiyono

    2009-08-19

    We consider a mass-less manifestly covariant {\\it linear} Schr\\"odinger equation. First, we show that it possesses a class of non-dispersive soliton solution with finite-size spatio-temporal support inside which the quantum amplitude satisfies the Klein-Gordon equation with finite {\\it emergent} mass. We then proceed to interpret the soliton wave function as describing a particle with finite mass, energy and momentum. Inside the spatio-temporal support, the wave function shows spatio-temporal internal vibration with angular frequency and wave number that are determined by the energy-momentum of the particle as firstly conjectured by de Broglie. Imposing resonance of the internal vibration inside the spatio-temporal support leads to Planck-Einstein quantization of energy-momentum. The first resonance mode is shown to recover the classical energy-momentum relation developed in special relativity. We further show that the linearity of the Schr\\"odinger equation allows one to construct many solitons solution through superposition, each describing a particle with various masses, energies and momenta.

  18. Plane-wave-based transfer-matrix method for photonic crystal functional elements

    NASA Astrophysics Data System (ADS)

    Li, Zhi-Yuan

    2005-01-01

    In this paper, we introduce a plane-wave-based transfer-matrix method (TMM) in application to photonic crystal (PC) functional elements and integrated circuits. In this formulation, the electromagnetic fields are expanded into superposition of plane waves associated with the crystal lattice, which facilitates access to many advanced Fourier analysis techniques. In addition to the standard solution of transmission, reflection and absorption spectra for a finite PC slab and photonic band structures for an infinite PC, the TMM can be used to handle wave propagation in semi-infinite photonic crystals and related waveguide structures. This capability is particularly useful for accurate solution of the intrinsic optical properties of a variety of functional elements comprising a PC integrated circuit. The TMM possesses a great advantage over the popular finite-different time-domain approach in handling these structures that are embedded in an environment of periodic geometries. We have discussed several prominent examples to demonstrate the power and capability of the TMM in this new frontier of applications. These include 2D PC filters based on resonant waveguide-cavity coupling, analysis of 2D channel add-drop filters that exhibit wideband continuous tunability, and discussion of the performance feature and radiation loss in resonant waveguide-cavity coupling based filters which are built on 2D slab PC platforms.

  19. Time Reversal Mirrors and Cross Correlation Functions in Acoustic Wave Propagation

    NASA Astrophysics Data System (ADS)

    Fishman, Louis; Jonsson, B. Lars G.; de Hoop, Maarten V.

    2009-03-01

    In time reversal acoustics (TRA), a signal is recorded by an array of transducers, time reversed, and then retransmitted into the configuration. The retransmitted signal propagates back through the same medium and retrofocuses on the source that generated the signal. If the transducer array is a single, planar (flat) surface, then this configuration is referred to as a planar, one-sided, time reversal mirror (TRM). In signal processing, for example, in active-source seismic interferometry, the measurement of the wave field at two distinct receivers, generated by a common source, is considered. Cross correlating these two observations and integrating the result over the sources yield the cross correlation function (CCF). Adopting the TRM experiments as the basic starting point and identifying the kinematically correct correspondences, it is established that the associated CCF signal processing constructions follow in a specific, infinite recording time limit. This perspective also provides for a natural rationale for selecting the Green's function components in the TRM and CCF expressions. For a planar, one-sided, TRM experiment and the corresponding CCF signal processing construction, in a three-dimensional homogeneous medium, the exact expressions are explicitly calculated, and the connecting limiting relationship verified. Finally, the TRM and CCF results are understood in terms of the underlying, governing, two-way wave equation, its corresponding time reversal invariance (TRI) symmetry, and the absence of TRI symmetry in the associated one-way wave equations, highlighting the role played by the evanescent modal contributions.

  20. Subspace accelerated inexact Newton method for large scale wave functions calculations in Density Functional Theory

    SciTech Connect

    Fattebert, J

    2008-07-29

    We describe an iterative algorithm to solve electronic structure problems in Density Functional Theory. The approach is presented as a Subspace Accelerated Inexact Newton (SAIN) solver for the non-linear Kohn-Sham equations. It is related to a class of iterative algorithms known as RMM-DIIS in the electronic structure community. The method is illustrated with examples of real applications using a finite difference discretization and multigrid preconditioning.

  1. Impact of Cerebrovascular Risk Factors on Brain Function and Structure in HIV-infected Individuals

    E-print Network

    Thompson, Paul

    Impact of Cerebrovascular Risk Factors on Brain Function and Structure in HIV-infected Individuals in this population. To date, the impact of CVD risk factors on cognition in the HIV infected population has not been (HAART). Traditional CVD risk factors such as dyslipidemia, hypertension, diabetes, and smoking are high

  2. Study on the propagation of coupling shock waves with phase transition under combined tension-torsion impact loading

    NASA Astrophysics Data System (ADS)

    Wang, Bo; Tang, ZhiPing

    2014-10-01

    Phase transition can strongly change the stress wave propagation features. In this paper, the characteristic wave propagation under combined tension and torsion impact loading was studied with a simplified constitutive model of phase transition considering both pressure and shear stress. The results showed that for loading from the austenitic phase to the mixed phase, the wave propagation was similar to that in the elasto-plastic materials. However, for an instantaneous loading from the austenitic phase or mixed phase directly to the martensitic phase, a coupling shock wave (CSHW) with phase transition was predicted due to the second phase strengthening effect, which has barely been studied before. Through analysis of the constitutive equations with phase transition and the discontinuity conditions of shock waves, the control equations of the generalized Hugoniot curve was obtained and the CSHW problem with phase transition was solved analytically. An independent numerical simulation of step loading along a NiTi thin walled tube suffering a combined tension-torsion impact loading was given to prove the existence of CSHW. The simulation discloses the formation mechanism of CSHW and the adjusting process of the stress state ahead of CSHW, which reflects the intrinsic characteristic of materials with strong nonlinear constitutive behavior.

  3. Size-consistent wave functions for nondynamical correlation energy: The valence active space optimized orbital coupled-cluster

    E-print Network

    Krylov, Anna I.

    Size-consistent wave functions for nondynamical correlation energy: The valence active space 6 July 1998; accepted 15 September 1998 The nondynamical correlation energy may be defined correlation energy, as defined above, involves computational complexity that grows exponentially

  4. Expressions for Neutrino Wave Functions and Transition Probabilities at Three Neutrino Oscillations in Vacuum and Some of Their Applications

    E-print Network

    Kh. M. Beshtoev

    2005-08-10

    We have considered three neutrino transitions and oscillations in the general case and obtained expressions for neutrino wave functions in three cases: with CP violation, without CP violations and the case when $\

  5. Electron-quasihole duality and second-order differential equation for Read-Rezayi and Jack wave functions

    SciTech Connect

    Estienne, Benoit [Institute for Theoretical Physics, Universiteit van Amsterdam, Valckenierstraat 65, 1018 XE Amsterdam (Netherlands); Bernevig, B. Andrei [Department of Physics, Princeton University, Princeton, New Jersey 08544 (United States); Santachiara, Raoul [LPTMS, UMR 8626, CNRS-Universite Paris-Sud, Batiment 100, 91405 Orsay (France)

    2010-11-15

    We consider the quasihole wave functions of the non-Abelian Read-Rezayi quantum-Hall states which are given by the conformal blocks of the minimal model WA{sub k-1}(k+1,k+2) of the WA{sub k-1} algebra. By studying the degenerate representations of this conformal field theories, we derive a second-order differential equation satisfied by a general many-quasihole wave function. We find a duality between the differential equations fixing the electron and quasihole wave functions. They both satisfy the Laplace-Beltrami equation. We use this equation to obtain an analytic expression for the generic wave function with one excess flux. These results also apply to the more general models WA{sub k-1}(k+1,k+r) corresponding to the recently introduced Jack states.

  6. Relational Interpretation of the Wave Function and a Possible Way Around Bell's Theorem

    NASA Astrophysics Data System (ADS)

    Filk, Thomas

    2006-06-01

    The famous “spooky action at a distance” in the EPR-scenario is shown to be a local interaction, once entanglement is interpreted as a kind of “nearest neighbor” relation among quantum systems. Furthermore, the wave function itself is interpreted as encoding the “nearest neighbor” relations between a quantum system and spatial points. This interpretation becomes natural, if we view space and distance in terms of relations among spatial points. Therefore, “position” becomes a purely relational concept. This relational picture leads to a new perspective onto the quantum mechanical formalism, where many of the “weird” aspects, like the particle-wave duality, the non-locality of entanglement, or the “mystery” of the double-slit experiment, disappear. Furthermore, this picture circumvents the restrictions set by Bell’s inequalities, i.e., a possible (realistic) hidden variable theory based on these concepts can be local and at the same time reproduce the results of quantum mechanics.

  7. Virial theorem for an inhomogeneous medium, boundary conditions for the wave functions, and stress tensor in quantum statistics.

    PubMed

    Bobrov, V B; Trigger, S A; van Heijst, G J F; Schram, P P J M

    2010-07-01

    On the basis of the stationary Schrödinger equation, the virial theorem in an inhomogeneous external field for the canonical ensemble is proved. It is shown that the difference in the form of virial theorem is conditioned by the value of the wave-function derivative on the surface of the volume, surrounding the system under consideration. The stress tensor in such a system is determined by the average values of the wave-function space derivatives. PMID:20866550

  8. Direct Measurement of the Pion Valence-Quark Momentum Distribution, the Pion Light-Cone Wave Function Squared

    Microsoft Academic Search

    E. M. Aitala; S. Amato; J. C. Anjos; J. A. Appel; D. Ashery; S. Banerjee; I. Bediaga; G. Blaylock; S. B. Bracker; R. A. Burnstein; T. Carter; H. S. Carvalho; N. K. Copty; L. M. Cremaldi; C. Darling; K. Denisenko; S. Deval; A. Fernandez; G. F. Fox; P. Gagnon; S. Gerzon; C. Gobel; K. Gounder; A. M. Halling; G. Herrera; G. Hurvits; C. James; P. A. Kasper; S. Kwan; D. C. Langs; J. Lichtenstadt; B. Lundberg; S. Maytal-Beck; B. Meadows; J. R. de Mello Neto; D. Mihalcea; R. H. Milburn; J. M. de Miranda; A. Napier; A. Nguyen; A. B. D'Oliveira; K. O'Shaughnessy; K. C. Peng; L. P. Perera; M. V. Purohit; B. Quinn; S. Radeztsky; A. Rafatian; N. W. Reay; J. J. Reidy; A. C. Dos Reis; H. A. Rubin; D. A. Sanders; A. K. Santha; A. F. Santoro; A. J. Schwartz; M. D. Sokoloff; R. A. Sidwell; A. J. Slaughter; J. Solano; N. R. Stanton; R. J. Stefanski; K. Stenson; D. J. Summers; S. Takach; K. Thorne; A. K. Tripathi; S. Watanabe; R. Weiss-Babai; J. Wiener; N. Witchey; E. Wolin; S. M. Yang; D. Yi; S. Yoshida; R. Zaliznyak; C. Zhang

    2001-01-01

    We present the first direct measurements of the pion valence-quark momentum distribution which is related to the square of the pion light-cone wave function. The measurements were carried out using data on diffractive dissociation of 500 GeV\\/c pi- into dijets from a platinum target at Fermilab experiment E791. The results show that the \\\\|qq¯> light-cone asymptotic wave function describes the

  9. Wave functions derived by quantum modeling of the electron density from coherent x-ray diffraction: Beryllium metal

    NASA Astrophysics Data System (ADS)

    Massa, L.; Goldberg, M.; Frishberg, C.; Boehme, R. F.; La Placa, S. J.

    1985-08-01

    A single-determinant experimental Be hybrid-atom wave function is obtained by the quantum formalism of Clinton and Massa, from Larsen and Hansen's single-crystal x-ray diffraction data. Physical properties calculable from this wave function are unobtainable from current methods of diffraction analysis. The least-squares fit using all experimental data gives an R factor of 0.0018, and quantitatively describes charge redistribution due to crystal bonding in agreement with ab initio calculations.

  10. ATOMIC AND MOLECULAR PHYSICS: Calculation of Energy and Other Properties of Muonic Helium Atom Using Boundary Conditions of Wave Function

    NASA Astrophysics Data System (ADS)

    Rezaei, B.

    2010-09-01

    The properties of muonic helium atom (4He+2?-e-) in ground state are considered. In this work, the energy and average distance between particles have been obtained using a wave function, which satisfies boundary conditions. It is shown that the obtained energy are very close to the values calculated by others. But the small differences of the expectation values of r2n are due to the incorporated boundary conditions in proposed wave function and are expected.

  11. Efficient calculation of 1-D periodic Green's functions for leaky-wave applications.

    SciTech Connect

    Baccarelli, Paolo (Sapienza University of Rome, Rome, Italy); Johnson, William Arthur; Paulotto, Simone (University of Houston, Houston, TX); Jackson, David R. (University of Houston, Houston, TX,); Wilton, Donald R. (University of Houston, Houston, TX,); Galli, A. (Sapienza University of Rome, Rome, Italy); Valero, G. (Sapienza University of Rome, Rome, Italy); Celepcikay, F. T. (University of Houston, Houston, TX,)

    2010-08-01

    In this paper an approach is described for the efficient computation of the mixed-potential scalar and dyadic Green's functions for a one-dimensional periodic (periodic along x direction) array of point sources embedded in a planar stratified structure. Suitable asymptotic extractions are performed on the slowly converging spectral series. The extracted terms are summed back through the Ewald method, modified and optimized to efficiently deal with all the different terms. The accelerated Green's functions allow for complex wavenumbers, and are thus suitable for application to leaky-wave antennas analysis. Suitable choices of the spectral integration paths are made in order to account for leakage effects and the proper/improper nature of the various space harmonics that form the 1-D periodic Green's function.

  12. Shear wave velocity variation across the Taupo Volcanic Zone, New Zealand, from receiver function inversion

    USGS Publications Warehouse

    Bannister, S.; Bryan, C.J.; Bibby, H.M.

    2004-01-01

    The Taupo Volcanic Zone (TVZ), New Zealand is a region characterized by very high magma eruption rates and extremely high heat flow, which is manifest in high-temperature geothermal waters. The shear wave velocity structure across the region is inferred using non-linear inversion of receiver functions, which were derived from teleseismic earthquake data. Results from the non-linear inversion, and from forward synthetic modelling, indicate low S velocities at ???6- 16 km depth near the Rotorua and Reporoa calderas. We infer these low-velocity layers to represent the presence of high-level bodies of partial melt associated with the volcanism. Receiver functions at other stations are complicated by reverberations associated with near-surface sedimentary layers. The receiver function data also indicate that the Moho lies between 25 and 30 km, deeper than the 15 ?? 2 km depth previously inferred for the crust-mantle boundary beneath the TVZ. ?? 2004 RAS.

  13. Constraining the Lithospheric Structure of the Central Andes Using P- and S- wave Receiver Functions

    NASA Astrophysics Data System (ADS)

    Ryan, J. C.; Beck, S. L.; Zandt, G.; Wagner, L. S.; Minaya, E.; Tavera, H.

    2014-12-01

    The Central Andean Plateau (CAP) has elevations in excess of 3 km, and is part of the Andean Cordillera that resulted in part from shortening along the western edge of South America as it was compressed between the subducting Nazca plate and underthrusting Brazilian cratonic lithosphere. We calculated P- and S-wave receiver functions for the Central Andean Uplift and Geodynamics of High Topography (CAUGHT) temporary deployment of broadband seismometers in the Bolivian orocline (12°-20°S) region to investigate crustal thickness and lithospheric structure. Migration of the receiver functions is done using common conversion point (CCP) stacks through a 3D shear velocity model from ambient noise tomography (Ward et al., 2013). The P- and S-wave receiver functions provide similar estimates of the depth to Moho under the CAP. Crustal thicknesses include 60-65 km thick crust underneath the Bolivian Altiplano, crust that varies from ~70 km to ~50 km underneath the Eastern Cordillera and Interandean zone, and thins to 50 to 40 km crust in the Subandes and the edge of the foreland. The variable crustal thickness of the Eastern Cordillera and Interandean zone ranges from >70 km associated with the Los Frailes volcanic field at 19°-20°S to ~55 km beneath the 6 km peaks of the Cordillera Real at ~16°S. From our S-wave receiver functions, that have no multiples that can interfere with deeper structure, we also identify structures below the Moho. Along a SW-NE line that runs near La Paz where we have our highest station density, the S-wave CCP receiver-function stacks show a strong negative polarity arrival at a depth of ~120 km from the eastern edge of the Altiplano to the Subandean zone. We suggest this may be a good candidate for the base of the CAP lithosphere. In addition, above this depth the mantle is strongly layered, suggesting that there is not a simple high velocity mantle lithosphere associated with the continental lithosphere underthrusting the Andean orogen from the east.

  14. Off-shell photon light-cone wave functions of odd chirality in the effective low-energy theory

    NASA Astrophysics Data System (ADS)

    Yu, Ran; Liu, Jueping; Zhu, Kai

    2006-02-01

    The Lorentz decomposition of the light-cone distribution amplitudes is carried out up to twist four. The Wandzura-Wilczek-like relations associated with the transverse photon wave function are derived in the same way as for the rho meson. The on-shell and off-shell photon wave functions with odd chirality at the leading twist in the effective low-energy theory derived from the instanton vacuum of QCD are calculated. The explicit expression of the transverse photon wave function, ???(u,P2), is worked out, and the twist-two parts of the other two photon wave functions, h??(s),twisttwo(u,P2) and h??(t),twisttwo(u,P2), are calculated based on the Wandzura-Wilczek-like relations. The dependence of the coupling f??(P2) and the light-cone photon wave functions with respect to the virtuality, P2, are analyzed, and the end-point behavior as well as the middle-point behavior of the photon wave functions is discussed.

  15. Off-shell photon light-cone wave functions of odd chirality in the effective low-energy theory

    SciTech Connect

    Yu Ran; Liu Jueping; Zhu Kai [Department of Physics, School of Physical Science and Technology, Wuhan University, 430072 Wuhan (China)

    2006-02-15

    The Lorentz decomposition of the light-cone distribution amplitudes is carried out up to twist four. The Wandzura-Wilczek-like relations associated with the transverse photon wave function are derived in the same way as for the rho meson. The on-shell and off-shell photon wave functions with odd chirality at the leading twist in the effective low-energy theory derived from the instanton vacuum of QCD are calculated. The explicit expression of the transverse photon wave function, {phi}{sub {gamma}}{sub perpendicular}(u,P{sup 2}), is worked out, and the twist-two parts of the other two photon wave functions, h{sub {gamma}}{sub parallel}{sup (s),twisttwo}(u,P{sup 2}) and h{sub {gamma}}{sub parallel}{sup (t),twisttwo}(u,P{sup 2}), are calculated based on the Wandzura-Wilczek-like relations. The dependence of the coupling f{sub {gamma}}{sup perpendicular}(P{sup 2}) and the light-cone photon wave functions with respect to the virtuality, P{sup 2}, are analyzed, and the end-point behavior as well as the middle-point behavior of the photon wave functions is discussed.

  16. Crustal thickness variation beneath the Romanian seismic network from Rayleigh wave dispersion and receiver function analysis

    NASA Astrophysics Data System (ADS)

    Tataru, Dragos; Grecu, Bogdan; Zaharia, Bogdan

    2014-05-01

    Variations in crustal thickness in Romania where determined by joint inversion of P wave receiver functions (RFs) and Rayleigh wave group velocity dispersion. We present new models of shear wave velocity structure of the crust beneath Romanian broad band stations. The data set consist in more than 500 teleseismic earthquake with epicentral distance between 30° and 95°, magnitude greater than 6 and a signal-to-noise ratio greater than 3 for the P-wave pulse. Most epicenters are situated along the northern Pacific Rim and arrive with backazimuths (BAZs) between 0° and 135° at the Romanian seismic network. We combine receiver functions with fundamental-mode of the Rayleigh wave group velocities to further constrain the shear-wave velocity structure.To extract the group velocities we applied the Multiple Filter Technique analysis to the vertical components of the earthquakes recordings. This technique allowed us to identify the Rayleigh wave fundamental mode and to compute the dispersion curves of the group velocities at periods between 10 and 150 s allowing us to resolve shear wave velocities to a depth of 100 km. The time-domain iterative deconvolution procedure of Ligorr?a and Ammon (1999) was employed to deconvolve the vertical component of the teleseismic P waveforms from the corresponding horizontal components and obtain radial and transverse receiver functions at each broadband station. The data are inverted using a joint, linearized inversion scheme (Hermann, 2002) which accounts for the relative influence of each set of observations, and allows a trade-off between fitting the observations, constructing a smooth model, and matching a priori constraints. The results show a thin crust for stations located inside the Pannonian basin (28-30 km) and a thicker crust for those in the East European Platform (36-40 km). The stations within the Southern and Central Carpathian Orogen are characterized by crustal depths of ~35 km. For stations located in the Northern part of the Eastern Carpathians we found a crustal depth of 32 km. For two station located in the Apuseni Mountains the Moho discontinuity is replace by a transition zone extended between 36 to 40 km depth. For a station located in the Carpathians bent area we identify a double Moho (32 respectively 44 km depth) possible due to the Vrancea subduction process. For the crust of Moesian Platform we get higher values (~35 km) compare to those obtained from seismic refraction profile (VRANCEA'2001). The North Dobrogea crust reaches a thickness of about 44-46 km. For most of the stations the crust-mantle transition zone has a significant gradient, with velocity values varying from 3.8 to 4.7 km/s. Our results are compatible with results from previous studies.

  17. Analytical structure and properties of Coulomb wave functions for real and complex energies

    NASA Astrophysics Data System (ADS)

    Humblet, J.

    1984-07-01

    The radical Coulomb wave functions are analysed in their dependence on the energy E considered as a complex parameter. Repulsive and attractive fields are both considered. First turning to the function ?l ? r- l-1 Fl introduced by Briet, slightly modifying its definition, and assuming that the angular momentum is also a complex parameter, for which the notation L is used, it is proved that ?L is an entire function of both E and L. From an expansion of the regular Whittaker function given by Buchholz, the Taylor expansion of ?L in powers of E and a simple recurrence relation for its coefficients are easily obtained. The expansion of the regular function Fl is readily obtained from that of ?L for L = l, but the irregular function Gl contains ?l and ?? L/?L for L = l and - l-1. Having proved that the expansion obtained for ?L in powers of E can also be regarded as a uniformly convergent series of entire functions of L, the derivative ?? L/?L can be obtained by term-by-term derivation. This method for obtaining the expansion of Gl is straightforward and leads to a final result involving essentially: (i) the conventional function h(?) = 1/2?(1 + i?) + 1/2?(1 - i?) - ln ? which is singular at ? = ?, i.e., at k = 0; (ii) two entire functions of E, namely ?l and ?l; the terms of the expansion of the latter in powers of E contain only Bessel functions multiplied by Bernoulli numbers and coefficients easily obtained from a simple recurrence relation. As an application of the above results, the last sections contain: (i) an alternate from of Gl expansion useful in numerical computations; (ii) the definition and expansion of two linearly independent solutions of the Coulomb equation which are entire in E; (iii) the expansion and threshold properties of the outgoing and incoming solutions, Ol and Il, corresponding to those we have obtained for Fl and Gl.

  18. Variational calculations of the effective potential with non-Gaussian trial wave functionals

    SciTech Connect

    Ibanez-Meier, R.; Mattingly, A.; Ritschel, U.; Stevenson, P.M. (T. W. Bonner Nuclear Laboratory, Physics Department, Rice University, Houston, Texas 77251 (United States))

    1992-04-15

    Variational calculations of the effective potential, going beyond the Gaussian approximation, are discussed in the context of {lambda}{phi}{sup 4} theory. Following Polley and Ritschel we use trial wave functionals obtained by a nontrivial unitary operator {ital U}={ital e}{sup {minus}{ital i}{ital s}{ital B}} acting on a Gaussian wave functional. We discuss in detail two cases in which the operator {ital B} has the forms (i) {ital B}={pi}{sup 3}, and (ii) {ital B}={pi}{sub {ital R}}{phi}{sub {ital T}}{sup 2}, where {phi} is the field operator and {pi} is its canonical conjugate. ({ital R} and {ital T} refer to radial and transverse directions in the O({ital N})-symmetric case.) We calculate the expectation value of the Hamiltonian in the non-Gaussian trial states thus generated, and obtain the optimization equations for the variational-parameter functions of the ansatz. These can be solved explicitly at {ital cphi}{sub {ital c}}=0 and lead to a nontrivial correction to the mass renormalization, with respect to the Gaussian case. Numerical results are obtained for the (0+1)-dimensional case, and show a worthwhile quantitative improvement over the Gaussian approximation.

  19. Study of Kinematics of Extreme Waves Impacting Offshore and Coastal Structures by Non Intrusive Measurement Techniques

    E-print Network

    Song, Youn Kyung

    2013-11-07

    , multiphase wave flow velocities during active interactions with various offshore and onshore ocean environments. First, initial inundation flow structures of tsunami-like long waves interacting with complex coastal topography are experimentally...

  20. Impact of ankylosing spondylitis on sexual function: A systematic review and meta-analysis

    PubMed Central

    LIU, YA-FEI; DONG, HUI; CHEN, ZHE; WANG, YU; TU, SHENG-HAO

    2015-01-01

    A number of studies have reported the association of sexual problems with ankylosing spondylitis (AS); however, the results have been conflicting. The present study aimed to investigate the impact of AS on sexual function. To develop a more comprehensive understanding of sexual function in patients with AS, a systematic review and meta-analysis of the literature up to 2013 was conducted. Studies that assessed the impact of AS on sexual function by adopting the International Index of Erectile Function or the Female Sexual Function Index (FSFI) scoring system were included. Statistical analysis was performed using Review Manager statistical software (version 5.2). The weighted mean differences were calculated by employing a fixed or random effects model. A total of 484 cases from five studies were identified as being well-documented and included in the meta-analysis. Compared with healthy controls, male patients with AS have a significant reduction in sexual function scores of erectile function (?3.07), orgasmic function (?1.17), sexual drive (?0.72) and intercourse satisfaction (?1.89). Female patients with AS have a lower FSFI score in domains of desire (?0.34) and arousal (?0.87). In conclusion, AS has a certain impact on the sexual function of male patients. AS appears to have a greater influence on the sexual function of males compared with that of females. However, the mechanism by which AS affects sexual function requires further evaluation by further studies of a larger population of patients. PMID:25780459