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Sample records for variational ground-state wave

  1. Useful variational principle for the scattering length for the target ground-state wave function imprecisely known

    International Nuclear Information System (INIS)

    Blau, R.; Rosenberg, L.; Spruch, L.

    1977-01-01

    A minimum principle for the calculation of the scattering length, applicable when the ground-state wave function of the target system is known precisely, has been available for some time. When, as is almost always the case, the target wave function is imprecisely known, a minimum principle is available but the simple minimum principle noted above is not applicable. Further, as recent calculations show, numerical instabilities usually arise which severely limit the utility of even an ordinary variational approach. The difficulty, which can be traced to the appearance of singularities in the variational construction, is here removed through the introduction of a minimum principle, not for the true scattering length, but for one associated with a closely connected problem. This guarantees that no instability difficulties can arise as the trial scattering wave function and the trial target wave function are improved. The calculations are little different from those required when the target ground-state wave function is known, and, in fact, the original version of the minimum principle is recovered as the trial target wave function becomes exact. A careful discussion is given of the types of problems to which the method can be applied. In particular, the effects of the Pauli principle, and the existence of a finite number of composite bound states, can be accounted for

  2. The two-hole ground state of the Hubbard-Anderson model, approximated by a variational RVB-type wave function

    NARCIS (Netherlands)

    Traa, M.R.M.J.; Traa, M.R.M.J.; Caspers, W.J.; Caspers, W.J.; Banning, E.J.; Banning, E.J.

    1994-01-01

    In this paper the Hubbard-Anderson model on a square lattice with two holes is studied. The ground state (GS) is approximated by a variational RVB-type wave function. The holes interact by exchange of a localized spin excitation (SE), which is created or absorbed if a hole moves to a

  3. Variational calculation for the ground state of 12C

    International Nuclear Information System (INIS)

    Consoni, L.H.A.; Coelho, H.T.; Das, T.K.

    1983-01-01

    A variational calculation is done for the ground state of a 3α-particle system. Two simple trial wavefunctions are used and results are compared with an exact calculation done by the Hyperspherical Harmonic method. A modifed Ali-Bodmer potential for the α-α interaction is considered for all calculations. It is found that these simple wave functions can be very useful for phenomenological calculations. (Author) [pt

  4. Ground-state densities from the Rayleigh-Ritz variation principle and from density-functional theory.

    Science.gov (United States)

    Kvaal, Simen; Helgaker, Trygve

    2015-11-14

    The relationship between the densities of ground-state wave functions (i.e., the minimizers of the Rayleigh-Ritz variation principle) and the ground-state densities in density-functional theory (i.e., the minimizers of the Hohenberg-Kohn variation principle) is studied within the framework of convex conjugation, in a generic setting covering molecular systems, solid-state systems, and more. Having introduced admissible density functionals as functionals that produce the exact ground-state energy for a given external potential by minimizing over densities in the Hohenberg-Kohn variation principle, necessary and sufficient conditions on such functionals are established to ensure that the Rayleigh-Ritz ground-state densities and the Hohenberg-Kohn ground-state densities are identical. We apply the results to molecular systems in the Born-Oppenheimer approximation. For any given potential v ∈ L(3/2)(ℝ(3)) + L(∞)(ℝ(3)), we establish a one-to-one correspondence between the mixed ground-state densities of the Rayleigh-Ritz variation principle and the mixed ground-state densities of the Hohenberg-Kohn variation principle when the Lieb density-matrix constrained-search universal density functional is taken as the admissible functional. A similar one-to-one correspondence is established between the pure ground-state densities of the Rayleigh-Ritz variation principle and the pure ground-state densities obtained using the Hohenberg-Kohn variation principle with the Levy-Lieb pure-state constrained-search functional. In other words, all physical ground-state densities (pure or mixed) are recovered with these functionals and no false densities (i.e., minimizing densities that are not physical) exist. The importance of topology (i.e., choice of Banach space of densities and potentials) is emphasized and illustrated. The relevance of these results for current-density-functional theory is examined.

  5. Green function iterative solution of ground state wave function for Yukawa potential

    International Nuclear Information System (INIS)

    Zhang Zhao

    2003-01-01

    The newly developed single trajectory quadrature method is applied to solve central potentials. First, based on the series expansion method an exact analytic solution of the ground state for Hulthen potential and an approximate solution for Yukawa potential are obtained respectively. Second, the newly developed iterative method based on Green function defined by quadratures along the single trajectory is applied to solve Yukawa potential using the Coulomb solution and Hulthen solution as the trial functions respectively. The results show that a more proper choice of the trial function will give a better convergence. To further improve the convergence the iterative method is combined with the variational method to solve the ground state wave function for Yukawa potential, using variational solutions of the Coulomb and Hulthen potentials as the trial functions. The results give much better convergence. Finally, the obtained critical screen coefficient is applied to discuss the dissociate temperature of J/ψ in high temperature QGP

  6. Ab initio calculation atomics ground state wave function for interactions Ion- Atom

    International Nuclear Information System (INIS)

    Shojaee, F.; Bolori zadeh, M. A.

    2007-01-01

    Ab initio calculation atomics ground state wave function for interactions Ion- Atom Atomic wave function expressed in a Slater - type basis obtained within Roothaan- Hartree - Fock for the ground state of the atoms He through B. The total energy is given for each atom.

  7. Many electron variational ground state of the two dimensional Anderson lattice

    International Nuclear Information System (INIS)

    Zhou, Y.; Bowen, S.P.; Mancini, J.D.

    1991-02-01

    A variational upper bound of the ground state energy of two dimensional finite Anderson lattices is determined as a function of lattice size (up to 16 x 16). Two different sets of many-electron basis vectors are used to determine the ground state for all values of the coulomb integral U. This variational scheme has been successfully tested for one dimensional models and should give good estimates in two dimensions

  8. Variational estimate of the vacuum state of the SU(2) lattice gauge theory with a disordered trial wave function

    International Nuclear Information System (INIS)

    Heys, D.W.; Stump, D.R.

    1984-01-01

    The variational principle is used to estimate the ground state of the Kogut-Susskind Hamiltonian of the SU(2) lattice gauge theory, with a trial wave function for which the magnetic fields on different plaquettes are uncorrelated. This trial function describes a disordered state. The energy expectation value is evaluated by a Monte Carlo method. The variational results are compared to similar results for a related Abelian gauge theory. Also, the expectation value of the Wilson loop operator is computed for the trial state, and the resulting estimate of the string tension is compared to the prediction of asymptotic freedom

  9. Derivation of the RPA (Random Phase Approximation) Equation of ATDDFT (Adiabatic Time Dependent Density Functional Ground State Response Theory) from an Excited State Variational Approach Based on the Ground State Functional.

    Science.gov (United States)

    Ziegler, Tom; Krykunov, Mykhaylo; Autschbach, Jochen

    2014-09-09

    The random phase approximation (RPA) equation of adiabatic time dependent density functional ground state response theory (ATDDFT) has been used extensively in studies of excited states. It extracts information about excited states from frequency dependent ground state response properties and avoids, thus, in an elegant way, direct Kohn-Sham calculations on excited states in accordance with the status of DFT as a ground state theory. Thus, excitation energies can be found as resonance poles of frequency dependent ground state polarizability from the eigenvalues of the RPA equation. ATDDFT is approximate in that it makes use of a frequency independent energy kernel derived from the ground state functional. It is shown in this study that one can derive the RPA equation of ATDDFT from a purely variational approach in which stationary states above the ground state are located using our constricted variational DFT (CV-DFT) method and the ground state functional. Thus, locating stationary states above the ground state due to one-electron excitations with a ground state functional is completely equivalent to solving the RPA equation of TDDFT employing the same functional. The present study is an extension of a previous work in which we demonstrated the equivalence between ATDDFT and CV-DFT within the Tamm-Dancoff approximation.

  10. Ground state energy and wave function of an off-centre donor in spherical core/shell nanostructures: Dielectric mismatch and impurity position effects

    Energy Technology Data Exchange (ETDEWEB)

    Ibral, Asmaa [Equipe d’Optique et Electronique du Solide, Département de Physique, Faculté des Sciences, Université Chouaïb Doukkali, B.P. 20 El Jadida Principale, El Jadida 24000 (Morocco); Laboratoire d’Instrumentation, Mesure et Contrôle, Département de Physique, Université Chouaïb Doukkali, B.P. 20 El Jadida Principale, El Jadida (Morocco); Zouitine, Asmae [Département de Physique, Ecole Nationale Supérieure d’Enseignement Technique, Université Mohammed V Souissi, B.P. 6207 Rabat-Instituts, Rabat (Morocco); Assaid, El Mahdi, E-mail: eassaid@yahoo.fr [Equipe d’Optique et Electronique du Solide, Département de Physique, Faculté des Sciences, Université Chouaïb Doukkali, B.P. 20 El Jadida Principale, El Jadida 24000 (Morocco); Laboratoire d’Instrumentation, Mesure et Contrôle, Département de Physique, Université Chouaïb Doukkali, B.P. 20 El Jadida Principale, El Jadida (Morocco); Feddi, El Mustapha [Département de Physique, Ecole Nationale Supérieure d’Enseignement Technique, Université Mohammed V Souissi, B.P. 6207 Rabat-Instituts, Rabat (Morocco); and others

    2014-09-15

    Ground state energy and wave function of a hydrogen-like off-centre donor impurity, confined anywhere in a ZnS/CdSe spherical core/shell nanostructure are determined in the framework of the envelope function approximation. Conduction band-edge alignment between core and shell of nanostructure is described by a finite height barrier. Dielectric constant mismatch at the surface where core and shell materials meet is taken into account. Electron effective mass mismatch at the inner surface between core and shell is considered. A trial wave function where coulomb attraction between electron and off-centre ionized donor is used to calculate ground state energy via the Ritz variational principle. The numerical approach developed enables access to the dependence of binding energy, coulomb correlation parameter, spatial extension and radial probability density with respect to core radius, shell radius and impurity position inside ZnS/CdSe core/shell nanostructure.

  11. Ground state energy and wave function of an off-centre donor in spherical core/shell nanostructures: Dielectric mismatch and impurity position effects

    International Nuclear Information System (INIS)

    Ibral, Asmaa; Zouitine, Asmae; Assaid, El Mahdi; Feddi, El Mustapha

    2014-01-01

    Ground state energy and wave function of a hydrogen-like off-centre donor impurity, confined anywhere in a ZnS/CdSe spherical core/shell nanostructure are determined in the framework of the envelope function approximation. Conduction band-edge alignment between core and shell of nanostructure is described by a finite height barrier. Dielectric constant mismatch at the surface where core and shell materials meet is taken into account. Electron effective mass mismatch at the inner surface between core and shell is considered. A trial wave function where coulomb attraction between electron and off-centre ionized donor is used to calculate ground state energy via the Ritz variational principle. The numerical approach developed enables access to the dependence of binding energy, coulomb correlation parameter, spatial extension and radial probability density with respect to core radius, shell radius and impurity position inside ZnS/CdSe core/shell nanostructure

  12. The effect of regional variation of seismic wave attenuation on the strong ground motion from earthquakes

    Energy Technology Data Exchange (ETDEWEB)

    Chung, D H; Bernreuter, D L

    1981-10-01

    Attenuation is caused by geometric spreading and absorption. Geometric spreading is almost independent of crustal geology and physiographic region, but absorption depends strongly on crustal geology and the state of the earth's upper mantle. Except for very high frequency waves, absorption does not affect ground motion at distances less than about 25 to 50 km. Thus, in the near-field zone, the attenuation in the eastern United States is similar to that in the western United States. Beyond the near field, differences in ground motion can best be accounted for by differences in attenuation caused by differences in absorption. The stress drop of eastern earthquakes may be higher than for western earthquakes of the same seismic moment, which would affect the high-frequency spectral content. But we believe this factor is of much less significance than differences in absorption in explaining the differences in ground motion between the East and the West. The characteristics of strong ground motion in the conterminous United States are discussed in light of these considerations, and estimates are made of the epicentral ground motions in the central and eastern United States. (author)

  13. Evolution of ground-state wave function in CeCoIn5 upon Cd or Sn doping

    Science.gov (United States)

    Chen, K.; Strigari, F.; Sundermann, M.; Hu, Z.; Fisk, Z.; Bauer, E. D.; Rosa, P. F. S.; Sarrao, J. L.; Thompson, J. D.; Herrero-Martin, J.; Pellegrin, E.; Betto, D.; Kummer, K.; Tanaka, A.; Wirth, S.; Severing, A.

    2018-01-01

    We present linear polarization-dependent soft-x-ray absorption spectroscopy data at the Ce M4 ,5 edges of Cd- and Sn-doped CeCoIn5. The 4 f ground-state wave functions have been determined for their superconducting, antiferromagnetic, and paramagnetic ground states. The absence of changes in the wave functions in CeCo (In1-xCdx) 5 suggests that the 4 f -conduction-electron (c f ) hybridization is not affected by global Cd doping, thus supporting the interpretation of magnetic droplets nucleating long-range magnetic order. This is contrasted by changes in the wave function due to Sn substitution. Increasing Sn in CeCo (In1-ySny) 5 compresses the 4 f orbitals into the tetragonal plane of these materials, suggesting enhanced c f hybridization with the in-plane In(1) atoms and a homogeneous altering of the electronic structure. As these experiments show, the 4 f wave functions are a very sensitive probe of small changes in the hybridization of 4 f and conduction electrons, even conveying information about direction dependencies.

  14. Learning Approach on the Ground State Energy Calculation of Helium Atom

    International Nuclear Information System (INIS)

    Shah, Syed Naseem Hussain

    2010-01-01

    This research investigated the role of learning approach on the ground state energy calculation of Helium atom in improving the concepts of science teachers at university level. As the exact solution of several particles is not possible here we used approximation methods. Using this method one can understand easily the calculation of ground state energy of any given function. Variation Method is one of the most useful approximation methods in estimating the energy eigen values of the ground state and the first few excited states of a system, which we only have a qualitative idea about the wave function.The objective of this approach is to introduce and involve university teacher in new research, to improve their class room practices and to enable teachers to foster critical thinking in students.

  15. Variational theory of nuclear and neutron matter

    International Nuclear Information System (INIS)

    Pandharipande, V.R.; Wiringa, R.B.

    1989-06-01

    In these lectures we will discuss attempts to solve the A = 3 to ∞ nuclear many-body problems with the variational method. We choose the form of a variational wave function Χ v (1, 2 hor-ellipsis A) to describe the ground state. The Χ v and the ground-state energy E v are obtained by minimizing E v = left-angle Χ v |H|Χ v right-angle/left-angle Χ v |Χ v right-angle with respect to variations in Χ v . If the form of the variational wave function is chosen properly we can expect Χ v ∼ Χ 0 and E v ∼ E 0 where Χ 0 and E 0 are the exact ground-state wave function and energy. In general E v ≥ E 0 in variational calculations. 63 refs., 11 figs

  16. Hartree-Fock implementation using a Laguerre-based wave function for the ground state and correlation energies of two-electron atoms.

    Science.gov (United States)

    King, Andrew W; Baskerville, Adam L; Cox, Hazel

    2018-03-13

    An implementation of the Hartree-Fock (HF) method using a Laguerre-based wave function is described and used to accurately study the ground state of two-electron atoms in the fixed nucleus approximation, and by comparison with fully correlated (FC) energies, used to determine accurate electron correlation energies. A variational parameter A is included in the wave function and is shown to rapidly increase the convergence of the energy. The one-electron integrals are solved by series solution and an analytical form is found for the two-electron integrals. This methodology is used to produce accurate wave functions, energies and expectation values for the helium isoelectronic sequence, including at low nuclear charge just prior to electron detachment. Additionally, the critical nuclear charge for binding two electrons within the HF approach is calculated and determined to be Z HF C =1.031 177 528.This article is part of the theme issue 'Modern theoretical chemistry'. © 2018 The Author(s).

  17. Variational theory of nuclear and neutron matter

    Energy Technology Data Exchange (ETDEWEB)

    Pandharipande, V.R.; Wiringa, R.B. (Illinois Univ., Urbana, IL (USA). Dept. of Physics; Argonne National Lab., IL (USA))

    1989-06-01

    In these lectures we will discuss attempts to solve the A = 3 to {infinity} nuclear many-body problems with the variational method. We choose the form of a variational wave function {Chi}{sub v}(1, 2{hor ellipsis}A) to describe the ground state. The {Chi}{sub v} and the ground-state energy E{sub v} are obtained by minimizing E{sub v} = {l angle}{Chi}{sub v}{vert bar}H{vert bar}{Chi}{sub v}{r angle}/{l angle}{Chi}{sub v}{vert bar}{Chi}{sub v}{r angle} with respect to variations in {Chi}{sub v}. If the form of the variational wave function is chosen properly we can expect {Chi}{sub v} {approx} {Chi}{sub 0} and E{sub v} {approx} E{sub 0} where {Chi}{sub 0} and E{sub 0} are the exact ground-state wave function and energy. In general E{sub v} {ge} E{sub 0} in variational calculations. 63 refs., 11 figs.

  18. Fate of the open-shell singlet ground state in the experimentally accessible acenes: A quantum Monte Carlo study

    Science.gov (United States)

    Dupuy, Nicolas; Casula, Michele

    2018-04-01

    By means of the Jastrow correlated antisymmetrized geminal power (JAGP) wave function and quantum Monte Carlo (QMC) methods, we study the ground state properties of the oligoacene series, up to the nonacene. The JAGP is the accurate variational realization of the resonating-valence-bond (RVB) ansatz proposed by Pauling and Wheland to describe aromatic compounds. We show that the long-ranged RVB correlations built in the acenes' ground state are detrimental for the occurrence of open-shell diradical or polyradical instabilities, previously found by lower-level theories. We substantiate our outcome by a direct comparison with another wave function, tailored to be an open-shell singlet (OSS) for long-enough acenes. By comparing on the same footing the RVB and OSS wave functions, both optimized at a variational QMC level and further projected by the lattice regularized diffusion Monte Carlo method, we prove that the RVB wave function has always a lower variational energy and better nodes than the OSS, for all molecular species considered in this work. The entangled multi-reference RVB state acts against the electron edge localization implied by the OSS wave function and weakens the diradical tendency for higher oligoacenes. These properties are reflected by several descriptors, including wave function parameters, bond length alternation, aromatic indices, and spin-spin correlation functions. In this context, we propose a new aromatic index estimator suitable for geminal wave functions. For the largest acenes taken into account, the long-range decay of the charge-charge correlation functions is compatible with a quasi-metallic behavior.

  19. Surface Waves Propagating on Grounded Anisotropic Dielectric Slab

    Directory of Open Access Journals (Sweden)

    Zhuozhu Chen

    2018-01-01

    Full Text Available This paper investigates the characteristics of surface waves propagating on a grounded anisotropic dielectric slab. Distinct from the existing analyses that generally assume that the fields of surface wave uniformly distribute along the transverse direction of the infinitely large grounded slab, our method takes into account the field variations along the transverse direction of a finite-width slab. By solving Maxwell’s equations in closed-form, it is revealed that no pure transverse magnetic (TM or transverse electric (TE mode exists if the fields are non-uniformly distributed along the transverse direction of the grounded slab. Instead, two hybrid modes, namely quasi-TM and quasi-TE modes, are supported. In addition, the propagation characteristics of two hybrid modes supported by the grounded anisotropic slab are analyzed in terms of the slab thickness, slab width, as well as the relative permittivity tensor of the anisotropic slab. Furthermore, different methods are employed to compare the analyses, as well as to validate our derivations. The proposed method is very suitable for practical engineering applications.

  20. Variational-integral perturbation corrections of some lower excited states for hydrogen atoms in magnetic fields

    International Nuclear Information System (INIS)

    Yuan Lin; Zhou Ben-Hu; Zhao Yun-Hui; Xu Jun; Hai Wen-Hua

    2012-01-01

    A variational-integral perturbation method (VIPM) is established by combining the variational perturbation with the integral perturbation. The first-order corrected wave functions are constructed, and the second-order energy corrections for the ground state and several lower excited states are calculated by applying the VIPM to the hydrogen atom in a strong uniform magnetic field. Our calculations demonstrated that the energy calculated by the VIPM only shows a negative value, which indicates that the VIPM method is more accurate than the other methods. Our study indicated that the VIPM can not only increase the accuracy of the results but also keep the convergence of the wave functions

  1. Variational Monte Carlo study of pentaquark states

    Energy Technology Data Exchange (ETDEWEB)

    Mark W. Paris

    2005-07-01

    Accurate numerical solution of the five-body Schrodinger equation is effected via variational Monte Carlo. The spectrum is assumed to exhibit a narrow resonance with strangeness S=+1. A fully antisymmetrized and pair-correlated five-quark wave function is obtained for the assumed non-relativistic Hamiltonian which has spin, isospin, and color dependent pair interactions and many-body confining terms which are fixed by the non-exotic spectra. Gauge field dynamics are modeled via flux tube exchange factors. The energy determined for the ground states with J=1/2 and negative (positive) parity is 2.22 GeV (2.50 GeV). A lower energy negative parity state is consistent with recent lattice results. The short-range structure of the state is analyzed via its diquark content.

  2. Topological Invariants and Ground-State Wave functions of Topological Insulators on a Torus

    Directory of Open Access Journals (Sweden)

    Zhong Wang

    2014-01-01

    Full Text Available We define topological invariants in terms of the ground-state wave functions on a torus. This approach leads to precisely defined formulas for the Hall conductance in four dimensions and the topological magnetoelectric θ term in three dimensions, and their generalizations in higher dimensions. They are valid in the presence of arbitrary many-body interactions and disorder. These topological invariants systematically generalize the two-dimensional Niu-Thouless-Wu formula and will be useful in numerical calculations of disordered topological insulators and strongly correlated topological insulators, especially fractional topological insulators.

  3. Calculation of the ground and excited states of the Ne2 molecule by the variational cellular method

    International Nuclear Information System (INIS)

    Dias, A.M.; Rosato, A.

    1981-07-01

    The potential curves for the ground state 1 Σ + sub(g) and for the first singlet excited state 1 Σ + sub (u) of the Ne 2 molecule are determined by the Variational Cellular Method. From these curves some spectroscopical constants are obtained. Ionization energies of the excited state 1 Σ + sub (u) are calculated. (Author) [pt

  4. Ground States of Random Spanning Trees on a D-Wave 2X

    Science.gov (United States)

    Hall, J. S.; Hobl, L.; Novotny, M. A.; Michielsen, Kristel

    The performances of two D-Wave 2 machines (476 and 496 qubits) and of a 1097-qubit D-Wave 2X were investigated. Each chip has a Chimera interaction graph calG . Problem input consists of values for the fields hj and for the two-qubit interactions Ji , j of an Ising spin-glass problem formulated on calG . Output is returned in terms of a spin configuration {sj } , with sj = +/- 1 . We generated random spanning trees (RSTs) uniformly distributed over all spanning trees of calG . On the 476-qubit D-Wave 2, RSTs were generated on the full chip with Ji , j = - 1 and hj = 0 and solved one thousand times. The distribution of solution energies and the average magnetization of each qubit were determined. On both the 476- and 1097-qubit machines, four identical spanning trees were generated on each quadrant of the chip. The statistical independence of these regions was investigated. In another study, on the D-Wave 2X, one hundred RSTs with random Ji , j ∈ { - 1 , 1 } and hj = 0 were generated on the full chip. Each RST problem was solved one hundred times and the number of times the ground state energy was found was recorded. This procedure was repeated for square subgraphs, with dimensions ranging from 7 ×7 to 11 ×11. Supported in part by NSF Grants DGE-0947419 and DMR-1206233. D-Wave time provided by D-Wave Systems and by the USRA Quantum Artificial Intelligence Laboratory Research Opportunity.

  5. Application of Stochastic variational method with correlated Ground States to coulombic systems

    Energy Technology Data Exchange (ETDEWEB)

    Usukura, Junko; Suzuki, Yasuyuki [Niigata Univ. (Japan); Varga, K.

    1998-07-01

    Positronium molecule, Ps{sub 2} has not been found experimentally yet, and it has been believed theoretically that Ps{sub 2} has only one bound state with L = 0. We predicted the existence of new bound state of Ps{sub 2}, which is the excited state with L = 1 and comes from Pauli principle, by Stochastic variational method. There are two decay mode with respect to Ps{sub 2}(P); one is pair annihilation and another is electric dipole (E1) transition to the ground state. While it is difficult to tell {gamma}-ray caused by annihilation of Ps{sub 2} from that of Ps since both of them have same energy, Energy (4.94 eV) of the photon emitted in E1 transition is specific enough to distinguish from other spectra. Then the excited state is one of clues to observe Ps{sub 2}. (author)

  6. On the ground state of Yang-Mills theory

    OpenAIRE

    Bakry, Ahmed S.; Leinweber, Derek B.; Williams, Anthony G.

    2011-01-01

    We investigate the overlap of the ground state meson potential with sets of mesonic-trial wave functions corresponding to different gluonic distributions. We probe the transverse structure of the flux tube through the creation of non-uniform smearing profiles for the string of glue connecting two color sources in Wilson loop operator. The non-uniformly UV-regulated flux-tube operators are found to optimize the overlap with the ground state and display interesting features in the ground state ...

  7. On the ground state of Yang-Mills theory

    Science.gov (United States)

    Bakry, Ahmed S.; Leinweber, Derek B.; Williams, Anthony G.

    2011-08-01

    We investigate the overlap of the ground state meson potential with sets of mesonic-trial wave functions corresponding to different gluonic distributions. We probe the transverse structure of the flux tube through the creation of non-uniform smearing profiles for the string of glue connecting two color sources in Wilson loop operator. The non-uniformly UV-regulated flux-tube operators are found to optimize the overlap with the ground state and display interesting features in the ground state overlap.

  8. On the ground state of Yang-Mills theory

    International Nuclear Information System (INIS)

    Bakry, Ahmed S.; Leinweber, Derek B.; Williams, Anthony G.

    2011-01-01

    Highlights: → The ground state overlap for sets of meson potential trial states is measured. → Non-uniform gluonic distributions are probed via Wilson loop operator. → The locally UV-regulated flux-tube operators can optimize the ground state overlap. - Abstract: We investigate the overlap of the ground state meson potential with sets of mesonic-trial wave functions corresponding to different gluonic distributions. We probe the transverse structure of the flux tube through the creation of non-uniform smearing profiles for the string of glue connecting two color sources in Wilson loop operator. The non-uniformly UV-regulated flux-tube operators are found to optimize the overlap with the ground state and display interesting features in the ground state overlap.

  9. Multisatellite and ground-based observations of transient ULF waves

    International Nuclear Information System (INIS)

    Potemra, T.A.; Zanetti, L.J.; Takahashi, K.; Erlandson, R.E.; Luehr, H.; Marklund, G.T.; Block, L.P.; Blomberg, L.G.; Lepping, R.P.

    1989-01-01

    A unique alignment of the Active Magnetospheric Particle Tracer Explorers (AMPTE) CCE and Viking satellites with respect to the EISCAT Magnetometer Cross has provided an opportunity to study transient ULF pulsations associated with variations in solar wind plasma density observed by the IMP 8 satellite. These observations were acquired during a relatively quiet period on April 24, 1986, during the Polar Region and Outer Magnetosphere International Study (PROMIS) period. An isolated 4-mHz (4-min period) pulsation was detected on the ground which was associated with transverse magnetic field oscillations observed by Viking at a ∼ 2-R E altitude above the auroral zone and by CCE at ∼ 8-R E in the equatorial plane on nearly the same flux tube. CCE detected a compressional oscillation in the magnetic field with twice the period (∼ 10 min) of the transverse waves, and with a waveform nearly identical to an isolated oscillation in the solar wind plasma density measured by IMP 8. The authors conclude that the isolated 10-min oscillation in solar wind plasma density produced magnetic field compression oscillations inside the magnetosphere at the same frequency which also enhanced resonant oscillations at approximately twice the frequency that were already present. The ground magnetic field variations are due to ionospheric Hall currents driven by the electric field of the standing Alfven waves. The time delay between surface and satellite data acquired at different local times supports the conclusion that the periodic solar wind density variation excites a tailward traveling large-scale magnetosphere wave train which excites local field line resonant oscillations. They conclude that these transient magnetic field variations are not associated with magnetic field reconnection or flux transfer events

  10. Calculation of the ground and excited states of the Ne2 molecule by the Variational Cellular Method

    International Nuclear Information System (INIS)

    Dias, A.M.; Rosato, A.

    1982-01-01

    The potential curves for the ground 1 μ + sub(g) and for the first singlet excited state 1 μ + sub(u) of the Ne 2 molecule are determined by the Variational Cellular Method. From these curves some spectroscopical constants are obtained. Ionization energies of the excited state 1 μ + sub(u) are calculated. (Author) [pt

  11. Solid hydrogen and deuterium. I. Ground-state energy calculated by a lowest order constrained-variation method

    International Nuclear Information System (INIS)

    Pettersen, G.; Oestgaard, E.

    1988-01-01

    The ground-state energy of solid hydrogen and deuterium is calculated by means of a modified variational lowest order constrained-variation (LOCV) method. Both fcc and hcp H 2 and D 2 are considered, and the calculations are done for five different two-body potentials. For solid H 2 we obtain theoretical results for the ground-state binding energy per particle from -74.9 K at an equilibrium particle density of 0.700 σ -3 or a molar volume of 22.3 cm 3 /mole to -91.3 K at a particle density of 0.725 σ -3 or a molar volume of 21.5 cm 3 /mole, where σ = 2.958 A. The corresponding experimental result is -92.3 K at a particle density of 0.688 σ -3 or a molar volume of 22.7 cm 3 /mole. For solid D 2 we obtain theoretical results for the ground-state binding energy per particle from -125.7 K at an equilibrium particle density of 0.830 σ -3 or a molar volume of 18.8 cm 3 /mole to -140.1 K at a particle density of 0.843 σ -3 or a molar volume of 18.5 cm 3 /mole. The corresponding experimental result is -137.9 K at a particle density of 0.797 σ -3 or a molar volume of 19.6 cm 3 /mole

  12. Research on Ground Motion Metal Target Based on Rocket Projectile by Using Millimeter Wave Radiometer Technology

    Directory of Open Access Journals (Sweden)

    Zhang Dongyang

    2014-06-01

    Full Text Available How to detect the ground motion metal target effectively is an important guarantee for precision strike in the process of Rocket Projectile flight. Accordingly and in view of the millimeter- wave radiation characteristic of the ground motion metal target, a mathematical model was established based on Rocket Projectile about millimeter-wave detection to the ground motion metal target. Through changing various parameters in the process of Rocket Projectile flight, the detection model was studied by simulation. The parameters variation and effective range of millimeter wave radiometer were obtained in the process of rotation and horizontal flight. So a certain theoretical basis was formed for the precision strike to the ground motion metal target.

  13. Variational theory of valence fluctuations: Ground states and quasiparticle excitations of the Anderson lattice model

    Science.gov (United States)

    Brandow, B. H.

    1986-01-01

    A variational study of ground states of the orbitally nondegenerate Anderson lattice model, using a wave function with one variational parameter per Bloch state k, has been extended to deal with essentially metallic systems having a nonintegral number of electrons per site. Quasiparticle excitations are obtained by direct appeal to Landau's original definition for interacting Fermi liquids, scrEqp(k,σ)=δEtotal/δn qp(k,σ). This approach provides a simple and explicit realization of the Luttinger picture of a periodic Fermi liquid. A close correspondence is maintained between the ``interacting'' (U=∞) system and the corresponding ``noninteracting'' (U=0) case, i.e., ordinary band theory; the result can be described as a renormalized band or renormalized hybridization theory. The occupation-number distribution for the conduction orbitals displays a finite discontinuity at the Fermi surface. If the d-f hybridization is nonzero throughout the Brillouin zone, the quasiparticle spectrum will always exhibit a gap, although this gap becomes exponentially small (i.e., of order TK) in the Kondo-lattice regime. In the ``ionic'' case with precisely two electrons per site, such a system may therefore exhibit an insulating (semiconducting) gap. The quasiparticle state density exhibits a prominent spike on each side of the spectral gap, just as in the elementary hybridization model (the U=0 case). For the metallic case, with a nonintegral number of electrons per site, the Fermi level falls within one of the two sharp density peaks. The effective mass at the Fermi surface tends to be very large; enhancements by a factor >~102 are quite feasible. The foregoing variational theory has also been refined by means of a trial wave function having two variational parameters per Bloch state k. The above qualitative features are all retained, with some quantitative differences, but there are also some qualitatively new features. The most interesting of these is the appearance, within

  14. Numerical study of ground state and low lying excitations of quantum antiferromagnets

    International Nuclear Information System (INIS)

    Trivedi, N.; Ceperley, D.M.

    1989-01-01

    The authors have studied, via Green function Monte Carlo (GFMC), the S = 1/2 Heisenberg quantum antiferromagnet in two dimensions on a square lattice. They obtain the ground state energy with only statistical errors E 0 /J = -0.6692(2), the staggered magnetization m † = 0.31(2), and from the long wave length behavior of the structure factor, the spin wave velocity c/c o = 1.14(5). They show that the ground state wave function has long range pair correlations arising from the zero point motion of spin waves

  15. Crystalline beam ground state

    International Nuclear Information System (INIS)

    Wei, Jie; Li, Xiao-Ping; Sessler, A.M.

    1993-01-01

    In order to employ Molecular Dynamics method, commonly used in condensed matter physics, we have derived the equations of motion for a beam of charged particles in the rotating rest frame of the reference particle. We include in the formalism that the particles are confined by the guiding and focusing magnetic fields, and that they are confined in a conducting vacuum pipe while interacting with each other via a Coulomb force. Numerical simulations has been performed to obtain the equilibrium structure. The effects of the shearing force, centrifugal force, and azimuthal variation of the focusing strength are investigated. It is found that a constant gradient storage ring can not give a crystalline beam, but that an alternating-gradient (AG) structure can. In such a machine the ground state is, except for one-dimensional (1-D) crystals, time-dependent. The ground state is a zero entropy state, despite the time-dependent, periodic variation of the focusing force. The nature of the ground state, similar to that found by Rahman and Schiffer, depends upon the density and the relative focusing strengths in the transverse directions. At low density, the crystal is 1-D. As the density increases, it transforms into various kinds of 2-D and 3-D crystals. If the energy of the beam is higher than the transition energy of the machine, the crystalline structure can not be formed for lack of radial focusing

  16. Crystalline beam ground state

    International Nuclear Information System (INIS)

    Wei, Jie; Li, Xiao-Ping

    1993-01-01

    In order to employ molecular dynamics (MD) methods, commonly used in condensed matter physics, we have derived the equations of motion for a beam of charged particles in the rotating rest frame of the reference particle. We include in the formalism that the particles are confined by the guiding and focusing magnetic fields, and that they are confined in a conducting vacuum pipe while interacting with each other via a Coulomb force. Numerical simulations using MD methods has been performed to obtain the equilibrium crystalline beam structure. The effect of the shearing force, centrifugal force, and azimuthal variation of the focusing strength are investigated. It is found that a constant gradient storage ring can not give a crystalline beam, but that an alternating-gradient (AG) structure can. In such a machine the ground state is, except for one-dimensional (1-D) crystals, time dependent. The ground state is a zero entropy state, despite the time-dependent, periodic variation of the focusing force. The nature of the ground state, similar to that found by Schiffer et al. depends upon the density and the relative focusing strengths in the transverse directions. At low density, the crystal is 1-D. As the density increases, it transforms into various kinds of 2-D and 3-D crystals. If the energy of the beam is higher than the transition energy of the machine, the crystalline structure can not be formed for lack of radial focusing

  17. Crystalline beam ground state

    International Nuclear Information System (INIS)

    Wei, J.; Li, X.P.

    1993-01-01

    In order to employ the Molecular Dynamics method, commonly used in condensed matter physics, the authors have derived the equations of motion for a beam of charged particles in the rotating rest frame of the reference particle. They include in the formalism that the particles are confined by the guiding and focusing magnetic fields, and that they are confined in a conducting vacuum pipe while interacting with each other via a Coulomb force. Numerical simulations has been performed to obtain the equilibrium structure. The effects of the shearing force, centrifugal force, and azimuthal variation of the focusing strength are investigated. It is found that a constant gradient storage ring can not give a crystalline beam, but that an alternating-gradient (AG) structure can. In such a machine the ground state is, except for one-dimensional (1-D) crystals, time-dependent. The ground state is a zero entropy state, despite the time-dependent, periodic variation of the focusing force. The nature of the ground state, similar to that found by Rahman and Schiffer, depends upon the density and the relative focusing strengths in the transverse directions. At low density, the crystal is 1-D. As the density increases, it transforms into various kinds of 2-D and 3-D crystals. If the energy of the beam is higher than the transition energy of the machine, the crystalline structure can not be formed for lack of radial focusing

  18. Effect of uniaxial stress on the acceptor ground state and on the hopping conduction in p-type germanium and silicon

    International Nuclear Information System (INIS)

    Buczko, R.; Chroboczek, J.A.

    1983-08-01

    We constructed variational wave functions, with correct asymptotic behaviour, for the ground state of shallow acceptors in Ge and Si, utilizing the spherical tensor representation of the effective mass hamiltonian of Baldereschi and Lipari (1973), at uniaxial stress, X, resulting from the application of a tensile or compressive force along the [001] orientation (respectively X 0). Energies of the components of the ground state, computed variationally, account very well for the X-induced displacements of the binding energies and the stress splitting of shallow acceptors in both Ge and Si, at X>0 (no data for X 0. However, they account only qualitatively for the rho(X) data available for Si (X>0 only), probably because of a larger chemical shift of the acceptor ground state in Si and its possible variation with X. At larger acceptor concentrations rho(X) decreases, at large X, much stronger than predicted for both Ge and Si. We attribute this discrepancy to the increase of the contribution to electron transport of multiple hopping transitions at large X values. (author)

  19. Calculation of the ground-state energy and average distance between particles for the nonsymmetric muonic 3He atom

    International Nuclear Information System (INIS)

    Eskandari, M.R.; Rezaie, B.

    2005-01-01

    A calculation of the ground-state energy and average distance between particles in the nonsymmetric muonic 3 He atom is given. We have used a wave function with one free parameter, which satisfies boundary conditions such as the behavior of the wave function when two particles are close to each other or far away. In the proposed wave function, the electron-muon correlation function is also considered. It has a correct behavior for r 12 tending to zero and infinity. The calculated values for the energy and expectation values of r 2n are compared with the multibox variational approach and the correlation function hyperspherical harmonic method. In addition, to show the importance and accuracy of approach used, the method is applied to evaluate the ground-state energy and average distance between the particles of nonsymmetric muonic 4 He atom. Our obtained results are very close to the values calculated by the mentioned methods and giving strong indications that the proposed wave functions, in addition to being very simple, provide relatively accurate values for the energy and expectation values of r 2n , emphasizing the importance of the local properties of the wave function

  20. Competing States in the t-J Model: Uniform d-Wave State versus Stripe State versus Stripe State

    NARCIS (Netherlands)

    Corboz, P.R.; Rice, T.M.; Troyer, M.

    2014-01-01

    Variational studies of the t-J model on the square lattice based on infinite projected-entangled pair states confirm an extremely close competition between a uniform d-wave superconducting state and different stripe states. The site-centered stripe with an in-phase d-wave order has an equal or only

  1. Variations of ULF wave power throughout the Halloween 2003 superstorm

    Science.gov (United States)

    Daglis, I.; Balasis, G.; Papadimitriou, C.; Zesta, E.; Georgiou, M.; Mann, I.

    2013-09-01

    Focused on the exceptional 2003 Halloween geospace magnetic storm, when Dst reached a minimum of -383 nT, we examine data from topside ionosphere and two magnetospheric missions (CHAMP, Cluster, and Geotail) for signatures of ULF waves. We present the overall ULF wave activity through the six-day interval from 27 October to 1 November 2003 as observed by the three spacecraft and by the Andenes ground magnetic station of the IMAGE magnetometerer array in terms of time variations of the ULF wave power. The ULF wave activity is divided upon Pc3 and Pc5 wave power. Thus, we provide different ULF wave activity indices according to the wave frequency (Pc3 and Pc5) and location of observation (Earth’s magnetosphere, topside ionosphere and surface). We also look at three specific intervals during different phases of the storm when at least two of the satellites are in good local time (LT) conjunction and examine separately Pc3 and Pc4-5 ULF wave activity and its concurrence in the different regions of the magnetosphere and down to the topside ionosphere and on the ground. This work has received support from the European Community’s Seventh Framework Programme under grant agreement no. 284520 for the MAARBLE (Monitoring, Analyzing and Assessing Radiation Belt Energization and Loss) collaborative research project.

  2. Ground state of charged Base and Fermi fluids in strong coupling

    International Nuclear Information System (INIS)

    Mazighi, R.

    1982-03-01

    The ground state and excited states of the charged Bose gas were studied (wave function, equation of state, thermodynamics, application of Feynman theory). The ground state of the charged Fermi gas was also investigated together with the miscibility of charged Bose and Fermi gases at 0 deg K (bosons-bosons, fermions-bosons and fermions-fermions) [fr

  3. Strong correlation effects on the d-wave superconductor- spectral weight analysis by variational wave functions

    International Nuclear Information System (INIS)

    Chou, C-P; Lee, T K; Ho, C-M

    2009-01-01

    We examine the strong correlation effects of the d-wave superconducting state by including the Gutzwiller projection for no electron double occupancy at each lattice site. The spectral weights (SW's) for adding and removing an electron on the projected superconducting state, the ground state of the 2-dimensional t-t'-t - J model with moderate doped holes describing the high T c cuprates, are studied numerically on finite lattices and compared with the observation made by low-temperature tunneling (particle asymmetry of tunneling conductance) and angle-resolved photoemission (SW transfer from the projected Fermi liquid state) spectroscopies. The contrast with the d-wave case without projection is alo presented.

  4. Frequency dependent polarizabilities for the ground state of H2, HD, and D2

    International Nuclear Information System (INIS)

    Rychlewski, J.

    1983-01-01

    A variation-perturbation method has been employed to calculate the dynamic dipole polarizability for the ground state of the hydrogen molecule. The explicit correlated electronic wave functions were used. The averaged values of α(#betta#) and #betta#(#betta#) for several vibration-rotation states of HD and D 2 are presented. Similar values for H 2 have also been calculated and were used to test the efficiency of the method and the validity of the assumption applied in the present calculation. The agreement of the present theoretical results with the existing experimental data is found to be satisfactory

  5. On the ground state for fractional quantum hall effect

    International Nuclear Information System (INIS)

    Jellal, A.

    1998-09-01

    In the present letter, we investigate the ground state wave function for an explicit model of electrons in an external magnetic field with specific inter-particle interactions. The excitation states of this model are also given. (author)

  6. Method and basis set dependence of anharmonic ground state nuclear wave functions and zero-point energies: Application to SSSH

    Science.gov (United States)

    Kolmann, Stephen J.; Jordan, Meredith J. T.

    2010-02-01

    One of the largest remaining errors in thermochemical calculations is the determination of the zero-point energy (ZPE). The fully coupled, anharmonic ZPE and ground state nuclear wave function of the SSSH radical are calculated using quantum diffusion Monte Carlo on interpolated potential energy surfaces (PESs) constructed using a variety of method and basis set combinations. The ZPE of SSSH, which is approximately 29 kJ mol-1 at the CCSD(T)/6-31G∗ level of theory, has a 4 kJ mol-1 dependence on the treatment of electron correlation. The anharmonic ZPEs are consistently 0.3 kJ mol-1 lower in energy than the harmonic ZPEs calculated at the Hartree-Fock and MP2 levels of theory, and 0.7 kJ mol-1 lower in energy at the CCSD(T)/6-31G∗ level of theory. Ideally, for sub-kJ mol-1 thermochemical accuracy, ZPEs should be calculated using correlated methods with as big a basis set as practicable. The ground state nuclear wave function of SSSH also has significant method and basis set dependence. The analysis of the nuclear wave function indicates that SSSH is localized to a single symmetry equivalent global minimum, despite having sufficient ZPE to be delocalized over both minima. As part of this work, modifications to the interpolated PES construction scheme of Collins and co-workers are presented.

  7. Method and basis set dependence of anharmonic ground state nuclear wave functions and zero-point energies: application to SSSH.

    Science.gov (United States)

    Kolmann, Stephen J; Jordan, Meredith J T

    2010-02-07

    One of the largest remaining errors in thermochemical calculations is the determination of the zero-point energy (ZPE). The fully coupled, anharmonic ZPE and ground state nuclear wave function of the SSSH radical are calculated using quantum diffusion Monte Carlo on interpolated potential energy surfaces (PESs) constructed using a variety of method and basis set combinations. The ZPE of SSSH, which is approximately 29 kJ mol(-1) at the CCSD(T)/6-31G* level of theory, has a 4 kJ mol(-1) dependence on the treatment of electron correlation. The anharmonic ZPEs are consistently 0.3 kJ mol(-1) lower in energy than the harmonic ZPEs calculated at the Hartree-Fock and MP2 levels of theory, and 0.7 kJ mol(-1) lower in energy at the CCSD(T)/6-31G* level of theory. Ideally, for sub-kJ mol(-1) thermochemical accuracy, ZPEs should be calculated using correlated methods with as big a basis set as practicable. The ground state nuclear wave function of SSSH also has significant method and basis set dependence. The analysis of the nuclear wave function indicates that SSSH is localized to a single symmetry equivalent global minimum, despite having sufficient ZPE to be delocalized over both minima. As part of this work, modifications to the interpolated PES construction scheme of Collins and co-workers are presented.

  8. Variational model for one-dimensional quantum magnets

    Science.gov (United States)

    Kudasov, Yu. B.; Kozabaranov, R. V.

    2018-04-01

    A new variational technique for investigation of the ground state and correlation functions in 1D quantum magnets is proposed. A spin Hamiltonian is reduced to a fermionic representation by the Jordan-Wigner transformation. The ground state is described by a new non-local trial wave function, and the total energy is calculated in an analytic form as a function of two variational parameters. This approach is demonstrated with an example of the XXZ-chain of spin-1/2 under a staggered magnetic field. Generalizations and applications of the variational technique for low-dimensional magnetic systems are discussed.

  9. Spin-Wave Wave Function for Quantum Spin Models : Condensed Matter and Statistical Physics

    OpenAIRE

    Franjo, FRANJIC; Sandro, SORELLA; Istituto Nazionale di Fisica della Materia International School for Advance Studies; Istituto Nazionale di Fisica della Materia International School for Advance Studies

    1997-01-01

    We present a new approach to determine an accurate variational wave function for general quantum spin models, completely defined by a consistency requirement with the simple and well-known linear spin-wave expansion. With this wave function, it is also possible to obtain the correct behavior of the long distance correlation functions for the 1D S=1/2 antiferromagnet. In 2D the proposed spin-wave wave function represents an excellent approximation to the exact ground state of the S=1.2 XY mode...

  10. Exponentially Biased Ground-State Sampling of Quantum Annealing Machines with Transverse-Field Driving Hamiltonians.

    Science.gov (United States)

    Mandrà, Salvatore; Zhu, Zheng; Katzgraber, Helmut G

    2017-02-17

    We study the performance of the D-Wave 2X quantum annealing machine on systems with well-controlled ground-state degeneracy. While obtaining the ground state of a spin-glass benchmark instance represents a difficult task, the gold standard for any optimization algorithm or machine is to sample all solutions that minimize the Hamiltonian with more or less equal probability. Our results show that while naive transverse-field quantum annealing on the D-Wave 2X device can find the ground-state energy of the problems, it is not well suited in identifying all degenerate ground-state configurations associated with a particular instance. Even worse, some states are exponentially suppressed, in agreement with previous studies on toy model problems [New J. Phys. 11, 073021 (2009)NJOPFM1367-263010.1088/1367-2630/11/7/073021]. These results suggest that more complex driving Hamiltonians are needed in future quantum annealing machines to ensure a fair sampling of the ground-state manifold.

  11. Variational study of fermionic and bosonic systems with non-Gaussian states: Theory and applications

    Science.gov (United States)

    Shi, Tao; Demler, Eugene; Ignacio Cirac, J.

    2018-03-01

    We present a new variational method for investigating the ground state and out of equilibrium dynamics of quantum many-body bosonic and fermionic systems. Our approach is based on constructing variational wavefunctions which extend Gaussian states by including generalized canonical transformations between the fields. The key advantage of such states compared to simple Gaussian states is presence of non-factorizable correlations and the possibility of describing states with strong entanglement between particles. In contrast to the commonly used canonical transformations, such as the polaron or Lang-Firsov transformations, we allow parameters of the transformations to be time dependent, which extends their regions of applicability. We derive equations of motion for the parameters characterizing the states both in real and imaginary time using the differential structure of the variational manifold. The ground state can be found by following the imaginary time evolution until it converges to a steady state. Collective excitations in the system can be obtained by linearizing the real-time equations of motion in the vicinity of the imaginary time steady-state solution. Our formalism allows us not only to determine the energy spectrum of quasiparticles and their lifetime, but to obtain the complete spectral functions and to explore far out of equilibrium dynamics such as coherent evolution following a quantum quench. We illustrate and benchmark this framework with several examples: a single polaron in the Holstein and Su-Schrieffer-Heeger models, non-equilibrium dynamics in the spin-boson and Kondo models, the superconducting to charge density wave phase transitions in the Holstein model.

  12. Assessing ground compaction via time lapse surface wave analysis

    Czech Academy of Sciences Publication Activity Database

    Dal Moro, Giancarlo; Al-Arifi, N.; Moustafa, S.S.R.

    2016-01-01

    Roč. 13, č. 3 (2016), s. 249-256 ISSN 1214-9705 Institutional support: RVO:67985891 Keywords : Full velocity spectrum (FVS) analysis * ground compaction * ground compaction * phase velocities * Rayleigh waves * seismic data inversion * surface wave dispersion * surface waves Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 0.699, year: 2016

  13. Variational minimization of atomic and molecular ground-state energies via the two-particle reduced density matrix

    International Nuclear Information System (INIS)

    Mazziotti, David A.

    2002-01-01

    Atomic and molecular ground-state energies are variationally determined by constraining the two-particle reduced density matrix (2-RDM) to satisfy positivity conditions. Because each positivity condition corresponds to correcting the ground-state energies for a class of Hamiltonians with two-particle interactions, these conditions collectively provide a new approach to many-body theory that, unlike perturbation theory, can capture significantly correlated phenomena including the multireference effects of potential-energy surfaces. The D, Q, and G conditions for the 2-RDM are extended through generalized lifting operators inspired from the formal solution of N-representability. These lifted conditions agree with the hierarchy of positivity conditions presented by Mazziotti and Erdahl [Phys. Rev. A 63, 042113 (2001)]. The connection between positivity and the formal solution explains how constraining higher RDMs to be positive semidefinite improves the N representability of the 2-RDM and suggests using pieces of higher positivity conditions that computationally scale like the D condition. With the D, Q, and G conditions as well as pieces of higher positivity the electronic energies for Be, LiH, H 2 O, and BH are computed through a primal-dual interior-point algorithm for positive semidefinite programming. The variational method produces potential-energy surfaces that are highly accurate even far from the equilibrium geometry where single-reference perturbation-based methods often fail to produce realistic energies

  14. Ground state phase diagram of extended attractive Hubbard model

    International Nuclear Information System (INIS)

    Robaszkiewicz, S.; Chao, K.A.; Micnas, R.

    1980-08-01

    The ground state phase diagram of the extended Hubbard model with intraatomic attraction has been derived in the Hartree-Fock approximation formulated in terms of the Bogoliubov variational approach. For a given value of electron density, the nature of the ordered ground state depends essentially on the sign and the strength of the nearest neighbor coupling. (author)

  15. Calculations of the ground state of 16O

    International Nuclear Information System (INIS)

    Pieper, S.C.

    1989-01-01

    One of the central problems in nuclear physics is the description of nuclei as systems of nucleons interacting via realistic potentials. There are two main aspects of this problem: specification of the Hamiltonian, and calculation of the ground states of nuclei with the given interaction. Realistic interactions must contain both two- and three-nucleon potentials and these potentials have a complicated non-central operator structure consisting, for example, of spin, isospin and tensor dependences. This structure results in formidable many-body problems in the computation of the ground states of nuclei. At present, reliable solutions of the Faddeev equations for the A = 3 nuclei with such interactions are routine. Recently, Carlson has made an essentially exact GFMC calculation of the He ground state using just a two-nucleon interaction, and there are reliable variational calculations for more complete potential models. Nuclear matter calculations can also be made with reasonable reliability. However, there have been very few calculations of nuclei with A > 5 using realistic interactions, and none with a modern three-nucleon interaction. In the present paper I present a new technique for variational calculations for such nuclei and apply it to the ground state of 16 O. 15 refs., 2 figs., 3 tabs

  16. Variation principle for nonlinear wave propagation

    International Nuclear Information System (INIS)

    Watanabe, T.; Lee, Y.C.; Nishikawa, Kyoji; Hojo, H.; Yoshida, Y.

    1976-01-01

    Variation principle is derived which determines stationary nonlinear propagation of electrostatic waves in the self-consistent density profile. Example is given for lower-hybrid waves and the relation to the variation principle for the Lagrangian density of electromagnetic fluids is discussed

  17. Ground-state fidelity in the BCS-BEC crossover

    International Nuclear Information System (INIS)

    Khan, Ayan; Pieri, Pierbiagio

    2009-01-01

    The ground-state fidelity has been introduced recently as a tool to investigate quantum phase transitions. Here, we apply this concept in the context of a crossover problem. Specifically, we calculate the fidelity susceptibility for the BCS ground-state wave function, when the intensity of the fermionic attraction is varied from weak to strong in an interacting Fermi system, through the BCS-Bose-Einstein Condensation crossover. Results are presented for contact and finite-range attractive potentials and for both continuum and lattice models. We conclude that the fidelity susceptibility can be useful also in the context of crossover problems.

  18. Determination of many-electron basis functions for a quantum Hall ground state using Schur polynomials

    Science.gov (United States)

    Mandal, Sudhansu S.; Mukherjee, Sutirtha; Ray, Koushik

    2018-03-01

    A method for determining the ground state of a planar interacting many-electron system in a magnetic field perpendicular to the plane is described. The ground state wave-function is expressed as a linear combination of a set of basis functions. Given only the flux and the number of electrons describing an incompressible state, we use the combinatorics of partitioning the flux among the electrons to derive the basis wave-functions as linear combinations of Schur polynomials. The procedure ensures that the basis wave-functions form representations of the angular momentum algebra. We exemplify the method by deriving the basis functions for the 5/2 quantum Hall state with a few particles. We find that one of the basis functions is precisely the Moore-Read Pfaffian wave function.

  19. Variational transition state theory

    International Nuclear Information System (INIS)

    Truhlar, D.G.

    1986-01-01

    This project is concerned with the development and applications of generalized transition state theory and multidimensional tunneling approximations to chemical reaction rates. They have developed and implemented several practical versions of variational transition state theory (VTST), namely canonical variational theory (CVT), improved canonical variational theory (ICVT), and microcanonical variational theory (μVT). They have also developed and implemented several accurate multidimensional semiclassical tunneling approximations, the most accurate of which are the small-curvature semiclassical adiabatic (SCSA), large-curvature version-3 (LC3), and least-action (LA) approximations. They have applied the methods to thermal rate constants, using transmission coefficients based on ground-state tunneling, and they have also presented and applied adiabatic and diabatic extensions to calculated rate constants for vibrationally excited reactants. Their general goal is to develop accurate methods for calculating chemical reaction rate constants that remain practical even for reasonably complicated molecules. The approximations mentioned above yield rate constants for systems whose potential energy surface is known or assumed. Thus a second, equally important aspect of their work is the determination or modeling, semi-empirically and/or from electronic structure calculations, of potential energy surfaces

  20. Theory of Nonlinear Dispersive Waves and Selection of the Ground State

    International Nuclear Information System (INIS)

    Soffer, A.; Weinstein, M.I.

    2005-01-01

    A theory of time-dependent nonlinear dispersive equations of the Schroedinger or Gross-Pitaevskii and Hartree type is developed. The short, intermediate and large time behavior is found, by deriving nonlinear master equations (NLME), governing the evolution of the mode powers, and by a novel multitime scale analysis of these equations. The scattering theory is developed and coherent resonance phenomena and associated lifetimes are derived. Applications include Bose-Einstein condensate large time dynamics and nonlinear optical systems. The theory reveals a nonlinear transition phenomenon, 'selection of the ground state', and NLME predicts the decay of excited state, with half its energy transferred to the ground state and half to radiation modes. Our results predict the recent experimental observations of Mandelik et al. in nonlinear optical waveguides

  1. Boson and fermion many-body assemblies: Fingerprints of excitations in the ground-state wave functions, with examples of superfluid 4He and the homogeneous correlated electron liquid

    International Nuclear Information System (INIS)

    March, N.H.

    2007-08-01

    After a brief summary of some basic properties of ideal gases of bosons and of fermions, two many-body Hamiltonians are cited for which ground-state wave functions allow the generation of excited states. But because of the complexity of ground-state many-body wave functions, we then consider properties of reduced density matrices, and in particular, the diagonal element of the second-order density matrix. For both the homogeneous correlated electron liquid and for an assembly of charged bosons, the ground-state pair correlation function g(r) has fingerprints of the zero-point energy of the plasmon modes. These affect crucially the static structure factor S(k), in the long wavelength limit. This is best understood by means of the Ornstein-Zernike direct correlation function c(r), which plays an important role throughout this article. Turning from such charged liquids, both boson and fermion, to superfluid 4 He, the elevated temperature (T) structure factor S(k, T) is related, albeit approximately, to its zero-temperature counterpart, via the velocity of sound, reflecting the collective phonon excitations, and the superfluid density. Finally some future directions are pointed. (author)

  2. Variational Monte Carlo calculations of nuclear ground states

    International Nuclear Information System (INIS)

    Wiringa, R.B.

    1990-01-01

    A major goal in nuclear physics is to understand how nuclear structure comes about from the underlying interactions between nucleons. This requires modelling nuclei as collections of strongly interacting nucleons. We start with realistic nucleon-nucleon potentials, supplemented with consistent three-nucleon potentials and two-body electroweak current operators, and try to predict nuclear ground properties, such as the binding energy, density and momentum distributions, and electromagnetic form factors. We also seek to predict other properties of nuclei such as excited states and low-energy reactions. 21 refs., 14 figs., 5 tabs

  3. Wave propagation through disordered media without backscattering and intensity variations

    Institute of Scientific and Technical Information of China (English)

    Konstantinos G Makris; Andre Brandst(o)tter; Philipp Ambichl; Ziad H Musslimani; Stefan Rotter

    2017-01-01

    A fundamental manifestation of wave scattering in a disordered medium is the highly complex intensity pattern the waves acquire due to multi-path interference.Here we show that these intensity variations can be entirely suppressed by adding disorder-specific gain and loss components to the medium.The resulting constant-intensity waves in such non-Hermitian scattering landscapes are free of any backscattering and feature perfect transmission through the disorder.An experimental demonstration of these unique wave states is envisioned based on spatially modulated pump beams that can flexibly control the gain and loss components in an active medium.

  4. Ground-state splitting of ultrashallow thermal donors with negative central-cell corrections in silicon

    Science.gov (United States)

    Hara, Akito; Awano, Teruyoshi

    2017-06-01

    Ultrashallow thermal donors (USTDs), which consist of light element impurities such as carbon, hydrogen, and oxygen, have been found in Czochralski silicon (CZ Si) crystals. To the best of our knowledge, these are the shallowest hydrogen-like donors with negative central-cell corrections in Si. We observed the ground-state splitting of USTDs by far-infrared optical absorption at different temperatures. The upper ground-state levels are approximately 4 meV higher than the ground-state levels. This energy level splitting is also consistent with that obtained by thermal excitation from the ground state to the upper ground state. This is direct evidence that the wave function of the USTD ground state is made up of a linear combination of conduction band minimums.

  5. Correlated wave functions for three-particle systems with Coulomb interaction - The muonic helium atom

    Science.gov (United States)

    Huang, K.-N.

    1977-01-01

    A computational procedure for calculating correlated wave functions is proposed for three-particle systems interacting through Coulomb forces. Calculations are carried out for the muonic helium atom. Variational wave functions which explicitly contain interparticle coordinates are presented for the ground and excited states. General Hylleraas-type trial functions are used as the basis for the correlated wave functions. Excited-state energies of the muonic helium atom computed from 1- and 35-term wave functions are listed for four states.

  6. The ground state energy of a bound polaron in the presence of a magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Zorkani, I [International Centre for Theoretical Physics, Trieste (Italy); Belhissi, R [Faculte des Sciences Dhar Mahraz, Fes (Morocco). Dept. de Physique

    1995-09-01

    A theoretical calculation for the ground state energy of a bound polaron as a function of the magnetic field is presented. The theory is based on a variational approach using a trial wave function proposed by Devreese et al. in the absence of the magnetic field. It was shown that his function is adequate for all electron - phonon coupling {alpha} and all parameter {gamma}{sub 0} which is the ratio between the L.O. phonon energy and the Colombian one. Analytical results are obtained in the weak coupling limit. (author). 27 refs, 4 figs, 1 tab.

  7. Variational principles for dissipative waves

    Science.gov (United States)

    Dodin, I. Y.; Ruiz, D. E.

    2016-10-01

    Variational methods are a powerful tool in plasma theory. However, their applications are typically restricted to conservative systems or require doubling of variables, which often contradicts the purpose of the variational approach altogether. We show that these restrictions can be relaxed for some classes of dynamical systems that are of practical interest in plasma physics, particularly including dissipative plasma waves. Applications will be discussed to calculating dispersion relations and modulational dynamics of individual plasma waves and wave ensembles. The work was supported by the NNSA SSAA Program through DOE Research Grant No. DE-NA0002948, by the U.S. DOE through Contract No. DE-AC02-09CH11466, and by the U.S. DOD NDSEG Fellowship through Contract No. 32-CFR-168a.

  8. Photoionization of furan from the ground and excited electronic states.

    Science.gov (United States)

    Ponzi, Aurora; Sapunar, Marin; Angeli, Celestino; Cimiraglia, Renzo; Došlić, Nađa; Decleva, Piero

    2016-02-28

    Here we present a comparative computational study of the photoionization of furan from the ground and the two lowest-lying excited electronic states. The study aims to assess the quality of the computational methods currently employed for treating bound and continuum states in photoionization. For the ionization from the ground electronic state, we show that the Dyson orbital approach combined with an accurate solution of the continuum one particle wave functions in a multicenter B-spline basis, at the density functional theory (DFT) level, provides cross sections and asymmetry parameters in excellent agreement with experimental data. On the contrary, when the Dyson orbitals approach is combined with the Coulomb and orthogonalized Coulomb treatments of the continuum, the results are qualitatively different. In excited electronic states, three electronic structure methods, TDDFT, ADC(2), and CASSCF, have been used for the computation of the Dyson orbitals, while the continuum was treated at the B-spline/DFT level. We show that photoionization observables are sensitive probes of the nature of the excited states as well as of the quality of excited state wave functions. This paves the way for applications in more complex situations such as time resolved photoionization spectroscopy.

  9. Ground state and elementary excitations of a model valence-fluctuation system

    International Nuclear Information System (INIS)

    Brandow, B.H.

    1979-01-01

    The nature of the valence fluctuation problem is described, and motivations are given for an Anderson-lattice model Hamiltonian. A simple trial wave function is posed for the ground state, and the variational problem is solved. This demonstrates clearly that there is no Kondo-like divergence; the present concentrated Kondo problem is thus more simple mathematically than the sngle-impurity problem. Elementary excitations are studies by the Green's function techniques of Zubarev and Hubbard. Quenching of local moments and a large specific heat are found at low temperatures. The quasi-particle spectrum exhibits a gap, but epsilon/sub F/ does not lie in this gap. The insulation-like feature of SmB 6 , SmS, and TmSe at very low temperatures is explained in terms of a strongly reduced mobility for states near the gap, and reasons are given why this feature is not observed in other valence-fluctuation compounds. 73 references

  10. Multiconfiguration Pair-Density Functional Theory Outperforms Kohn-Sham Density Functional Theory and Multireference Perturbation Theory for Ground-State and Excited-State Charge Transfer.

    Science.gov (United States)

    Ghosh, Soumen; Sonnenberger, Andrew L; Hoyer, Chad E; Truhlar, Donald G; Gagliardi, Laura

    2015-08-11

    The correct description of charge transfer in ground and excited states is very important for molecular interactions, photochemistry, electrochemistry, and charge transport, but it is very challenging for Kohn-Sham (KS) density functional theory (DFT). KS-DFT exchange-correlation functionals without nonlocal exchange fail to describe both ground- and excited-state charge transfer properly. We have recently proposed a theory called multiconfiguration pair-density functional theory (MC-PDFT), which is based on a combination of multiconfiguration wave function theory with a new type of density functional called an on-top density functional. Here we have used MC-PDFT to study challenging ground- and excited-state charge-transfer processes by using on-top density functionals obtained by translating KS exchange-correlation functionals. For ground-state charge transfer, MC-PDFT performs better than either the PBE exchange-correlation functional or CASPT2 wave function theory. For excited-state charge transfer, MC-PDFT (unlike KS-DFT) shows qualitatively correct behavior at long-range with great improvement in predicted excitation energies.

  11. Observations of magnetohydrodynamic waves on the ground and on a satellite

    International Nuclear Information System (INIS)

    Lanzerotti, L.J.; Fukunishi, H.; Maclennan, C.G.; Cahill, L.J. Jr.

    1976-01-01

    A comparison is made of magnetohydrodynamic waves observed near the equator on Explorer 45 and at an array of ground stations in the northern hemisphere and at their conjugate station at Siple, Antartica. The data comparisons strongly support the notion that the observed waves can be considered odd mode standing waves in the magnetosphere. This conclusion has important implications for the interpretation of single-point satellite and/or ground measurements of ULF plasma wave phenomena in the magnetosphere. Further, the data comparisons strongly suggest that the overall ULF (approx.5-30 mHz) power levels are quite similar in the magnetosphere and on the ground, at least during the intervals studied

  12. Mitigation of Traffic-Induced Ground Vibration by Inclined Wave Barriers

    DEFF Research Database (Denmark)

    Andersen, Lars; Augustesen, Anders Hust

    2009-01-01

    Double sheet pile walls can be used as wave barriers in order to mitigate ground vibrations from railways. The present analysis concerns the efficiency of such barriers, especially with regard to the influence of the barrier inclination and the backfill between the walls. Thus, the screening capa...... of reference following the load. This allows a computation of the steady state response to a harmonically varying point source moving at different speeds typical for a train....

  13. Solvable model with an extreme AGP ground state: relationships among fermion pairs, pairons, and natural spin geminals

    International Nuclear Information System (INIS)

    Larson, E.G.

    1986-01-01

    A model many-fermion Hamiltonian is presented for which the ground state is asymptotically an Antisymmetrized Geminal Powers (AGP) wave function with largest possible greatest eigenvalue for its two-particle reduced density matrix. Closed analytical expressions and plane-wave expansions are presented for the generating geminal of the AGP ground state and for its one-particle reduced density matrix. The natural orbitals for this generating geminal are plane waves. The generating geminal shows intensely local character in its intracule and corresponds to the formation of a quasi-boson from two fermions. One may appropriately modify this generating geminal to introduce zero occupation numbers of its one-particle reduced density matrix and to make all the nonzero occupation numbers of its one-particle reduced density matrix equal, thus making this geminal a generator of an extreme AGP wave function, with an extreme large eigenvalue for its two-particle reduced density matrix. Closed analytical expressions are also given for this modified geminal and for its one-particle reduced density matrix. The similarities and differences of the features of this model and the accepted models of the superconducting ground state of electrons in metals, and the superfluid ground state of liquid He 4 are mentioned

  14. Ground-state properties of a dilute homogeneous Bose gas of hard disks in two dimensions

    International Nuclear Information System (INIS)

    Mazzanti, F.; Polls, A.; Fabrocini, A.

    2005-01-01

    The energy and structure of a dilute hard-disks Bose gas are studied in the framework of a variational many-body approach based on a Jastrow correlated ground-state wave function. The asymptotic behaviors of the radial distribution function and the one-body density matrix are analyzed after solving the Euler equation obtained by a free minimization of the hypernetted chain energy functional. Our results show important deviations from those of the available low density expansions, already at gas parameter values x∼0.001. The condensate fraction in 2D is also computed and found generally lower than the 3D one at the same x

  15. Numerical implementation of Voigt and Maxwell models for simulation of waves in the ground

    Directory of Open Access Journals (Sweden)

    Sheshenin Sergey Vladimirovich

    2014-12-01

    Full Text Available A lot of papers have been dedicated to simulation of dynamic processes in soil and underground structures. For example, some authors considered wave distribution in underground water pipes for creation of vibration monitoring system, others considered theoretical and algorithm aspects of efficient implementation of realistic seismic wave attenuation due to viscosity development with the help of Finite Difference Method, etc. The paper describes the numerical simulation, designed for simulation of the stress-strain state in the ground subjected to wave processes. We consider the ground with a concrete structure immersed in. The purpose of the work is the description of small vibrations in hard soil, which can nevertheless make undesirable impact on the objects in the ground or on the surface. Explicit Wilkins type scheme is used for time integration. It has proven to be successful, including the use in a well-known LS-DYNA code. As a result we created our own computer code based on the finite element method (FEM. An example of its practical usage is given.

  16. Exact many-electron ground states on diamond and triangle Hubbard chains

    International Nuclear Information System (INIS)

    Gulacsi, Zsolt; Kampf, Arno; Vollhardt, Dieter

    2009-01-01

    We construct exact ground states of interacting electrons on triangle and diamond Hubbard chains. The construction requires (1) a rewriting of the Hamiltonian into positive semidefinite form, (2) the construction of a many-electron ground state of this Hamiltonian, and (3) the proof of the uniqueness of the ground state. This approach works in any dimension, requires no integrability of the model, and only demands sufficiently many microscopic parameters in the Hamiltonian which have to fulfill certain relations. The scheme is first employed to construct exact ground state for the diamond Hubbard chain in a magnetic field. These ground states are found to exhibit a wide range of properties such as flat-band ferromagnetism and correlation induced metallic, half-metallic or insulating behavior, which can be tuned by changing the magnetic flux, local potentials, or electron density. Detailed proofs of the uniqueness of the ground states are presented. By the same technique exact ground states are constructed for triangle Hubbard chains and a one-dimensional periodic Anderson model with nearest-neighbor hybridization. They permit direct comparison with results obtained by variational techniques for f-electron ferromagnetism due to a flat band in CeRh 3 B 2 . (author)

  17. Symmetry Breaking Ground States of Bose-Einstein Condensates in 1D Double Square Well and Optical Lattice Well

    International Nuclear Information System (INIS)

    Yuan Qingxin; Ding Guohui

    2005-01-01

    We investigate the phenomena of symmetry breaking and phase transition in the ground state of Bose-Einstein condensates (BECs) trapped in a double square well and in an optical lattice well, respectively. By using standing-wave expansion method, we present symmetric and asymmetric ground state solutions of nonlinear Schroedinger equation (NLSE) with a symmetric double square well potential for attractive nonlinearity. In particular, we study the ground state wave function's properties by changing the depth of potential and atomic interactions (here we restrict ourselves to the attractive regime). By using the Fourier grid Hamiltonian method, we also reveal a phase transition of BECs trapped in one-dimensional optical lattice potential.

  18. Short-time variations of the ground water level

    International Nuclear Information System (INIS)

    Nilsson, Lars Y.

    1977-09-01

    Investigations have demonstrated that the ground water level of aquifers in the Swedish bedrock shows shorttime variations without changing their water content. The ground water level is among other things affected by regular tidal movements occuring in the ''solid'' crust of the earth variations in the atmospheric pressure strong earthquakes occuring in different parts of the world These effects proves that the system of fissures in the bedrock are not stable and that the ground water flow is influenced by both water- and airfilled fissures

  19. Variational random phase approximation for the anharmonic oscillator

    International Nuclear Information System (INIS)

    Dukelsky, J.; Schuck, P.

    1990-04-01

    The recently derived Variational Random Phase Approximation is examined using the anharmonic oscillator model. Special attention is paid to the ground state RPA wave function and the convergence of the proposed truncation scheme to obtain the diagonal density matrix. Comparison with the standard Coupled Cluster method is made

  20. Electromagnetic wave scattering by aerial and ground radar objects

    CERN Document Server

    Sukharevsky, Oleg I

    2014-01-01

    Electromagnetic Wave Scattering by Aerial and Ground Radar Objects presents the theory, original calculation methods, and computational results of the scattering characteristics of different aerial and ground radar objects. This must-have book provides essential background for computing electromagnetic wave scattering in the presence of different kinds of irregularities, as well as Summarizes fundamental electromagnetic statements such as the Lorentz reciprocity theorem and the image principleContains integral field representations enabling the study of scattering from various layered structur

  1. Energies and wave functions of an off-centre donor in hemispherical quantum dot: Two-dimensional finite difference approach and ritz variational principle

    Energy Technology Data Exchange (ETDEWEB)

    Nakra Mohajer, Soukaina; El Harouny, El Hassan [Laboratoire de Physique de la Matière Condensée, Département de Physique, Faculté des Sciences, Université Abdelmalek Essaadi, B.P. 2121 M’Hannech II, 93030 Tétouan (Morocco); Ibral, Asmaa [Equipe d’Optique et Electronique du Solide, Département de Physique, Faculté des Sciences, Université Chouaïb Doukkali, B. P. 20 El Jadida Principale, El Jadida (Morocco); Laboratoire d’Instrumentation, Mesure et Contrôle, Département de Physique, Faculté des Sciences, Université Chouaïb Doukkali, B. P. 20 El Jadida Principale, El Jadida (Morocco); El Khamkhami, Jamal [Laboratoire de Physique de la Matière Condensée, Département de Physique, Faculté des Sciences, Université Abdelmalek Essaadi, B.P. 2121 M’Hannech II, 93030 Tétouan (Morocco); and others

    2016-09-15

    Eigenvalues equation solutions of a hydrogen-like donor impurity, confined in a hemispherical quantum dot deposited on a wetting layer and capped by an insulating matrix, are determined in the framework of the effective mass approximation. Conduction band alignments at interfaces between quantum dot and surrounding materials are described by infinite height barriers. Ground and excited states energies and wave functions are determined analytically and via one-dimensional finite difference approach in case of an on-center donor. Donor impurity is then moved from center to pole of hemispherical quantum dot and eigenvalues equation is solved via Ritz variational principle, using a trial wave function where Coulomb attraction between electron and ionized donor is taken into account, and by two-dimensional finite difference approach. Numerical codes developed enable access to variations of donor total energy, binding energy, Coulomb correlation parameter, spatial extension and radial probability density with respect to hemisphere radius and impurity position inside the quantum dot.

  2. Energies and wave functions of an off-centre donor in hemispherical quantum dot: Two-dimensional finite difference approach and ritz variational principle

    International Nuclear Information System (INIS)

    Nakra Mohajer, Soukaina; El Harouny, El Hassan; Ibral, Asmaa; El Khamkhami, Jamal

    2016-01-01

    Eigenvalues equation solutions of a hydrogen-like donor impurity, confined in a hemispherical quantum dot deposited on a wetting layer and capped by an insulating matrix, are determined in the framework of the effective mass approximation. Conduction band alignments at interfaces between quantum dot and surrounding materials are described by infinite height barriers. Ground and excited states energies and wave functions are determined analytically and via one-dimensional finite difference approach in case of an on-center donor. Donor impurity is then moved from center to pole of hemispherical quantum dot and eigenvalues equation is solved via Ritz variational principle, using a trial wave function where Coulomb attraction between electron and ionized donor is taken into account, and by two-dimensional finite difference approach. Numerical codes developed enable access to variations of donor total energy, binding energy, Coulomb correlation parameter, spatial extension and radial probability density with respect to hemisphere radius and impurity position inside the quantum dot.

  3. Evaluation of ground stiffness parameters using continuous surface wave geophysics

    DEFF Research Database (Denmark)

    Gordon, Anne; Foged, Niels

    2000-01-01

    Present day knowledge of the magnitude of the strain levels in the ground associated with geotechnical structures, together with an increasing number of projects requiring the best estimates of ground movements around excavations, has led to, inter alia, increased interest in measuring the very......-small-strain stiffness of the ground Gmax. Continuous surface wave geophysics offers a quick, non-intrusive and economical way of making such measurements. This paper reviews the continuous surface wave techniques and evaluates, in engineering terms, the applicability of the method to the site investigation industry....

  4. Traces of Lorentz symmetry breaking in a hydrogen atom at ground state

    Science.gov (United States)

    Borges, L. H. C.; Barone, F. A.

    2016-02-01

    Some traces of a specific Lorentz symmetry breaking scenario in the ground state of the hydrogen atom are investigated. We use standard Rayleigh-Schrödinger perturbation theory in order to obtain the corrections to the ground state energy and the wave function. It is shown that an induced four-pole moment arises, due to the Lorentz symmetry breaking. The model considered is the one studied in Borges et al. (Eur Phys J C 74:2937, 2014), where the Lorentz symmetry is broken in the electromagnetic sector.

  5. Traces of Lorentz symmetry breaking in a hydrogen atom at ground state

    Energy Technology Data Exchange (ETDEWEB)

    Borges, L.H.C. [Universidade Federal do ABC, Centro de Ciencias Naturais e Humanas, Santo Andre, SP (Brazil); Barone, F.A. [IFQ-Universidade Federal de Itajuba, Itajuba, MG (Brazil)

    2016-02-15

    Some traces of a specific Lorentz symmetry breaking scenario in the ground state of the hydrogen atom are investigated. We use standard Rayleigh-Schroedinger perturbation theory in order to obtain the corrections to the ground state energy and the wave function. It is shown that an induced four-pole moment arises, due to the Lorentz symmetry breaking. The model considered is the one studied in Borges et al. (Eur Phys J C 74:2937, 2014), where the Lorentz symmetry is broken in the electromagnetic sector. (orig.)

  6. Traces of Lorentz symmetry breaking in a hydrogen atom at ground state

    International Nuclear Information System (INIS)

    Borges, L.H.C.; Barone, F.A.

    2016-01-01

    Some traces of a specific Lorentz symmetry breaking scenario in the ground state of the hydrogen atom are investigated. We use standard Rayleigh-Schroedinger perturbation theory in order to obtain the corrections to the ground state energy and the wave function. It is shown that an induced four-pole moment arises, due to the Lorentz symmetry breaking. The model considered is the one studied in Borges et al. (Eur Phys J C 74:2937, 2014), where the Lorentz symmetry is broken in the electromagnetic sector. (orig.)

  7. Monitoring and understanding changes in heat waves, cold waves, floods, and droughts in the United States: State of knowledge

    Science.gov (United States)

    Peterson, Thomas C.; Heim, Richard R.; Hirsch, Robert M.; Kaiser, Dale P.; Brooks, Harold; Diffenbaugh, Noah S.; Dole, Randall M.; Giovannettone, Jason P.; Guirguis, Kristen; Karl, Thomas R.; Katz, Richard W.; Kunkel, Kenneth E.; Lettenmaier, Dennis P.; McCabe, Gregory J.; Paciorek, Christopher J.; Ryberg, Karen R.; K Wolter, BS Silva; Schubert, Siegfried; Silva, Viviane B. S.; Stewart, Brooke C.; Vecchia, Aldo V.; Villarini, Gabriele; Vose, Russell S.; Walsh, John; Wehner, Michael; Wolock, David; Wolter, Klaus; Woodhouse, Connie A.; Wuebbles, Donald

    2013-01-01

    Weather and climate extremes have been varying and changing on many different time scales. In recent decades, heat waves have generally become more frequent across the United States, while cold waves have been decreasing. While this is in keeping with expectations in a warming climate, it turns out that decadal variations in the number of U.S. heat and cold waves do not correlate well with the observed U.S. warming during the last century. Annual peak flow data reveal that river flooding trends on the century scale do not show uniform changes across the country. While flood magnitudes in the Southwest have been decreasing, flood magnitudes in the Northeast and north-central United States have been increasing. Confounding the analysis of trends in river flooding is multiyear and even multidecadal variability likely caused by both large-scale atmospheric circulation changes and basin-scale “memory” in the form of soil moisture. Droughts also have long-term trends as well as multiyear and decadal variability. Instrumental data indicate that the Dust Bowl of the 1930s and the drought in the 1950s were the most significant twentieth-century droughts in the United States, while tree ring data indicate that the megadroughts over the twelfth century exceeded anything in the twentieth century in both spatial extent and duration. The state of knowledge of the factors that cause heat waves, cold waves, floods, and drought to change is fairly good with heat waves being the best understood.

  8. Effect of logarithmic terms on the energy level and wave function of a dtμ system

    International Nuclear Information System (INIS)

    Zhen, Z.

    1990-01-01

    The effect of the logarithmic terms on the ground-state energy level and wave function of a dtμ system is investigated. No significant contribution of the logarithmic terms on either the energy level or wave function is found. At the same time, we find the lowest upper bound of the ground-state energy ever obtained by the variational method using the Hylleraas-type trial function and that the corresponding wave function satisfies the cusp condition as r dt →0 automatically to a reasonable accuracy for r<3 (muonic a.u.), where r is the distance between the fused dt nuclear compound and the muon

  9. Variational optimization algorithms for uniform matrix product states

    Science.gov (United States)

    Zauner-Stauber, V.; Vanderstraeten, L.; Fishman, M. T.; Verstraete, F.; Haegeman, J.

    2018-01-01

    We combine the density matrix renormalization group (DMRG) with matrix product state tangent space concepts to construct a variational algorithm for finding ground states of one-dimensional quantum lattices in the thermodynamic limit. A careful comparison of this variational uniform matrix product state algorithm (VUMPS) with infinite density matrix renormalization group (IDMRG) and with infinite time evolving block decimation (ITEBD) reveals substantial gains in convergence speed and precision. We also demonstrate that VUMPS works very efficiently for Hamiltonians with long-range interactions and also for the simulation of two-dimensional models on infinite cylinders. The new algorithm can be conveniently implemented as an extension of an already existing DMRG implementation.

  10. A nonlinear programming approach to lower bounds for the ground-state energy of helium

    International Nuclear Information System (INIS)

    Porras, I.; Feldmann, D.M.; King, F.W.

    1999-01-01

    Lower-bound estimates for the ground-state energy of the helium atom are determined using nonlinear programming techniques. Optimized lower bounds are determined for single-particle, radially correlated, and general correlated wave functions. The local nature of the method employed makes it a very severe test of the accuracy of the wave function

  11. Nonspherical atomic ground-state densities and chemical deformation densities from x-ray scattering

    International Nuclear Information System (INIS)

    Ruedenberg, K.; Schwarz, W.H.E.

    1990-01-01

    Presuming that chemical insight can be gained from the difference between the molecular electron density and the superposition of the ground-state densities of the atoms in a molecule, it is pointed out that, for atoms with degenerate ground states, an unpromoted ''atom in a molecule'' is represented by a specific ensemble of the degenerate atomic ground-state wave functions and that this ensemble is determined by the anisotropic local surroundings. The resulting atomic density contributions are termed oriented ground state densities, and the corresponding density difference is called the chemical deformation density. The constraints implied by this conceptual approach for the atomic density contributions are formulated and a method is developed for determining them from x-ray scattering data. The electron density of the appropriate promolecule and its x-ray scattering are derived, the determination of the parameters of the promolecule is outlined, and the chemical deformation density is formulated

  12. Relativistic n-body wave equations in scalar quantum field theory

    International Nuclear Information System (INIS)

    Emami-Razavi, Mohsen

    2006-01-01

    The variational method in a reformulated Hamiltonian formalism of Quantum Field Theory (QFT) is used to derive relativistic n-body wave equations for scalar particles (bosons) interacting via a massive or massless mediating scalar field (the scalar Yukawa model). Simple Fock-space variational trial states are used to derive relativistic n-body wave equations. The equations are shown to have the Schroedinger non-relativistic limits, with Coulombic interparticle potentials in the case of a massless mediating field and Yukawa interparticle potentials in the case of a massive mediating field. Some examples of approximate ground state solutions of the n-body relativistic equations are obtained for various strengths of coupling, for both massive and massless mediating fields

  13. Regionalization of ground motion attenuation in the conterminous United States

    International Nuclear Information System (INIS)

    Chung, D.H.; Bernreuter, D.L.

    1979-01-01

    Attenuation results from geometric spreading and from absorption. The former is almost independent of crustal geology or physiographic region. The latter depends strongly on crustal geology and the state of the earth's upper mantle. Except for very high-frequency waves, absorption does not affect ground motion at distances less than 25 to 50 km. Thus, in the near-field zone, the attenuation in the eastern United States will be similar to that in the western United States. Most of the differences in ground motion can be accounted for by differences in attenuation caused by differences in absorption. The other important factor is that for some Western earthquakes the fault breaks the earth's surface, resulting in larger ground motion. No Eastern earthquakes are known to have broken the earth's surface by faulting. The stress drop of Eastern earthquakes may be higher than for Western earthquakes of the same seismic moment, which would affect the high-frequency spectral content. This factor is believed to be of much less significance than differences in absorption in explaining the differences in ground motion between the East and the West. 6 figures

  14. Investigation of Spatial Variation of Sea States Offshore of Humboldt Bay CA Using a Hindcast Model.

    Energy Technology Data Exchange (ETDEWEB)

    Dallman, Ann Renee; Neary, Vincent Sinclair

    2014-10-01

    Spatial variability of sea states is an important consideration when performing wave resource assessments and wave resource characterization studies for wave energy converter (WEC) test sites and commercial WEC deployments. This report examines the spatial variation of sea states offshore of Humboldt Bay, CA, using the wave model SWAN . The effect of depth and shoaling on bulk wave parameters is well resolved using the model SWAN with a 200 m grid. At this site, the degree of spatial variation of these bulk wave parameters, with shoaling generally perpendicular to the depth contours, is found to depend on the season. The variation in wave height , for example, was higher in the summer due to the wind and wave sheltering from the protruding land on the coastline north of the model domain. Ho wever, the spatial variation within an area of a potential Tier 1 WEC test site at 45 m depth and 1 square nautical mile is almost negligible; at most about 0.1 m in both winter and summer. The six wave characterization parameters recommended by the IEC 6 2600 - 101 TS were compared at several points along a line perpendicular to shore from the WEC test site . As expected, these parameters varied based on depth , but showed very similar seasonal trends.

  15. The ground state energy of 3He droplet in the LOCV framework

    International Nuclear Information System (INIS)

    Modarres, M.; Motahari, S.; Rajabi, A.

    2012-01-01

    The (extended) lowest order constrained variational method was used to calculate the ground state energy of liquid helium 3 ( 3 He) droplets at zero temperature. Different types of density distribution profiles, such as the Gaussian, the Quasi-Gaussian and the Woods-Saxon were used. It was shown that at least, on average, near 20 3 He atoms are needed to get the bound state for 3 He liquid droplet. Depending on the choice of the density profiles and the atomic radius of 3 He, the above estimate can increase to 300. Our calculated ground state energy and the number of atoms in liquid 3 He droplet were compared with those of Variational Monte Carlo method, Diffusion Monte Carlo method and Density Functional Theory, for which a reasonable agreement was found.

  16. Ground state representation of the infinite one-dimensional Heisenberg ferromagnet. Pt. 2

    International Nuclear Information System (INIS)

    Babbitt, D.; Thomas, L.

    1977-01-01

    In its ground state representation, the infinite, spin 1/2 Heisenberg chain provides a model for spin wave scattering, which entails many features of the quantum mechanical N-body problem. Here, we give a complete eigenfunction expansion for the Hamiltonian of the chain in this representation, for all numbers of spin waves. Our results resolve the questions of completeness and orthogonality of the eigenfunctions given by Bethe for finite chains, in the infinite volume limit. (orig.) [de

  17. A study of electron density profiles in relation to ionization sources and ground-based radio wave absorption measurements, part 1

    Science.gov (United States)

    Gnanalingam, S.; Kane, J. A.

    1973-01-01

    An extensive set of ground-based measurements of the diurnal variation of medium frequency radio wave adsorption and virtual height is analyzed in terms of current understanding of the D- and lower E-region ion production and loss process. When this is done a gross discrepancy arises, the source of which is not known.

  18. Ground state energy values and moments of the anharmonic oscillator

    International Nuclear Information System (INIS)

    Seetharaman, M.; Raghavan, Sekhar; Subba Rao, G.

    1981-01-01

    It is shown that a very satisfactory estimate of the energy values (for all values of the anharmonicity) and moments of the ground state of the quartic anharmonic oscillator can be obtained in the variational method, by considering trial wavefunctions which have the correct asymptotic properties. The results derived with a single variational parameter are a considerable improvement over the recent results of C.A. Ginsburg and E.W. Montroll (1978). (author)

  19. Experimental Measurement of Wave Field Variations around Wave Energy Converter Arrays

    Directory of Open Access Journals (Sweden)

    Louise O’Boyle

    2017-01-01

    Full Text Available Wave energy converters (WECs inherently extract energy from incident waves. For wave energy to become a significant power provider in the future, large farms of WECs will be required. This scale of energy extraction will increase the potential for changes in the local wave field and coastal environment. Assessment of these effects is necessary to inform decisions on the layout of wave farms for optimum power output and minimum environmental impact, as well as on potential site selection. An experimental campaign to map, at high resolution, the wave field variation around arrays of 5 oscillating water column WECs and a methodology for extracting scattered and radiated waves is presented. The results highlight the importance of accounting for the full extent of the WEC behavior when assessing impacts on the wave field. The effect of radiated waves on the wave field is not immediately apparent when considering changes to the entire wave spectrum, nor when observing changes in wave climate due to scattered and radiated waves superimposed together. The results show that radiated waves may account for up to 50% of the effects on wave climate in the near field in particular operating conditions.

  20. Systematic Convergence in Applying Variational Method to Double-Well Potential

    Science.gov (United States)

    Mei, Wai-Ning

    2016-01-01

    In this work, we demonstrate the application of the variational method by computing the ground- and first-excited state energies of a double-well potential. We start with the proper choice of the trial wave functions using optimized parameters, and notice that accurate expectation values in excellent agreement with the numerical results can be…

  1. Ground state solutions for non-local fractional Schrodinger equations

    Directory of Open Access Journals (Sweden)

    Yang Pu

    2015-08-01

    Full Text Available In this article, we study a time-independent fractional Schrodinger equation with non-local (regional diffusion $$ (-\\Delta^{\\alpha}_{\\rho}u + V(xu = f(x,u \\quad \\text{in }\\mathbb{R}^{N}, $$ where $\\alpha \\in (0,1$, $N > 2\\alpha$. We establish the existence of a non-negative ground state solution by variational methods.

  2. Ground penetrating radar antenna measurements based on plane-wave expansions

    DEFF Research Database (Denmark)

    Lenler-Eriksen, Hans-Rudolph; Meincke, Peter

    2005-01-01

    The plane-wave transmitting spectrum of the system consisting of the ground penetrating radar (GPR) antenna and the air-soil interface is measured using a loop buried in the soil. The plane-wave spectrum is used to determine various parameters characterizing the radiation of the GPR antenna...

  3. 2D XXZ model ground state properties using an analytic Lanczos expansion

    International Nuclear Information System (INIS)

    Witte, N.S.; Hollenberg, L.C.L.; Weihong Zheng

    1997-01-01

    A formalism was developed for calculating arbitrary expectation values for any extensive lattice Hamiltonian system using a new analytic Lanczos expansion, or plaquette expansion, and a recently proved exact theorem for ground state energies. The ground state energy, staggered magnetisation and the excited state gap of the 2D anisotropic antiferromagnetic Heisenberg Model are then calculated using this expansion for a range of anisotropy parameters and compared to other moment based techniques, such as the t-expansion, and spin-wave theory and series expansion methods. It was found that far from the isotropic point all moment methods give essentially very similar results, but near the isotopic point the plaquette expansion is generally better than the others. 20 refs., 6 tabs

  4. Spin Waves in Ho2Co17

    DEFF Research Database (Denmark)

    Clausen, Kurt Nørgaard; Lebech, Bente

    1980-01-01

    Spin wave excitations in a single crystal of Ho2Co17 have been studied at 4.8 and 78 K. The results are discussed in terms of a linear spin wave model. At 78 K both ground state and excited state spin waves are observed.......Spin wave excitations in a single crystal of Ho2Co17 have been studied at 4.8 and 78 K. The results are discussed in terms of a linear spin wave model. At 78 K both ground state and excited state spin waves are observed....

  5. The use of quadratic forms in the calculation of ground state electronic structures

    International Nuclear Information System (INIS)

    Keller, Jaime; Weinberger, Peter

    2006-01-01

    There are many examples in theoretical physics where a fundamental quantity can be considered a quadratic form ρ=Σ i ρ i =vertical bar Ψ vertical bar 2 and the corresponding linear form Ψ=Σ i ψ i is highly relevant for the physical problem under study. This, in particular, is the case of the density and the wave function in quantum mechanics. In the study of N-identical-fermion systems we have the additional feature that Ψ is a function of the 3N configuration space coordinates and ρ is defined in three-dimensional real space. For many-electron systems in the ground state the wave function and the Hamiltonian are to be expressed in terms of the configuration space (CS), a replica of real space for each electron. Here we present a geometric formulation of the CS, of the wave function, of the density, and of the Hamiltonian to compute the electronic structure of the system. Then, using the new geometric notation and the indistinguishability and equivalence of the electrons, we obtain an alternative computational method for the ground state of the system. We present the method and discuss its usefulness and relation to other approaches

  6. Evidence for unconventional d-wave superconducting state in CeCu{sub 2}Si{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Vieyra, Hugo A.; Geibel, Christoph; Steglich, Frank; Oeschler, Niels [Max-Planck-Institute for Chemical Physics of Solids, Dresden 01187 (Germany); Parker, David [US Naval Research Laboratory, Washington, DC 20375 (United States); Jeevan, Hirale S. [I. Physik. Institut, Georg-August-Universitaet Goettingen, Goettingen 37077 (Germany)

    2010-07-01

    The heavy-fermion CeCu{sub 2}Si{sub 2} represents a prime system to study unconventional superconductivity in the vicinity of a magnetic instability. Within the homogeneity range of pure CeCu{sub 2}Si{sub 2} different ground states can be obtained. S-type crystals exhibit a superconducting transition at T{sub c}=0.6 K, whereas A/S-type show in addition antiferromagnetic order at T{sub N}=0.8 K. In recent years, the synthesis techniques have been optimized in order to obtain large high-quality single crystals with well defined ground state properties. This allows the systematic study of the superconducting order parameter and its variation at the border with magnetic order. In this work, we present angular dependent resistivity measurements on high-quality S- and A/S-type single-crystalline CeCu{sub 2}Si{sub 2} samples. The experimental results for the angular dependence of the upper critical field B{sub c2} as well as theoretical calculations taking into account effects like the strong Pauli paramagnetism, hint towards an unconventional d-wave symmetry of the order parameter in CeCu{sub 2}Si{sub 2}.

  7. Ground state properties of exotic nuclei in deformed medium mass region

    International Nuclear Information System (INIS)

    Manju; Chatterjee, R.; Singh, Jagjit; Shubhchintak

    2017-01-01

    The dipole moment, size of the nucleus and other ground state properties of deformed nuclei 37 Mg and 31 Ne are presented. Furthermore with this deformed wave function the electric dipole strength distribution for deformed nuclei 37 Mg and 31 Ne is calculated. This will allow us to investigate the two dimensional scaling phenomenon with two parameters: quadrupole deformation and separation energy

  8. Models including electron correlation in relation to Fock's proposed expansion of the ground-state wave function of He-like atomic ions

    Energy Technology Data Exchange (ETDEWEB)

    Glasser, M. L.; March, N. H.; Nieto, L. M. [Departamento de Fisica Teorica, Atomica y Optica, Universidad de Valladolid, ES-47011 Valladolid, Spain and Department of Physics, Clarkson University, Potsdam, New York 13699 (United States); Department of Physics, University of Antwerp, BE-2020 Antwerp, Belgium and Department of Theoretical Chemistry, University of Oxford, Oxford OX1 2JD (United Kingdom); Departamento de Fisica Teorica, Atomica y Optica, Universidad de Valladolid, ES-47011 Valladolid (Spain)

    2011-12-15

    Here attention is first drawn to the importance of gaining insight into Fock's early proposal for expanding the ground-state wave function for He-like atomic ions in hyperspherical coordinates. We approach the problem via two solvable models, namely, (i) the s-term model put forth by Temkin [Phys. Rev. 126, 130 (1962)] and (ii) the Hookean atom model proposed by Kestner and Sinanoglu [Phys. Rev. 128, 2687 (1962)]. In both cases the local kinetic energy can be obtained explicitly in hyperspherical coordinates. Separation of variables occurs in both model wave functions, though in a different context in the two cases. Finally, a k-space formulation is proposed that should eventually result in distinctive identifying characteristics of Fock's nonanalyticities for He-like atomic ions when both electrons are close to the nucleus.

  9. Variational Boussinesq model for strongly nonlinear dispersive waves

    NARCIS (Netherlands)

    Lawrence, C.; Adytia, D.; van Groesen, E.

    2018-01-01

    For wave tank, coastal and oceanic applications, a fully nonlinear Variational Boussinesq model with optimized dispersion is derived and a simple Finite Element implementation is described. Improving a previous weakly nonlinear version, high waves over flat and varying bottom are shown to be

  10. Graphene ground states

    Science.gov (United States)

    Friedrich, Manuel; Stefanelli, Ulisse

    2018-06-01

    Graphene is locally two-dimensional but not flat. Nanoscale ripples appear in suspended samples and rolling up often occurs when boundaries are not fixed. We address this variety of graphene geometries by classifying all ground-state deformations of the hexagonal lattice with respect to configurational energies including two- and three-body terms. As a consequence, we prove that all ground-state deformations are either periodic in one direction, as in the case of ripples, or rolled up, as in the case of nanotubes.

  11. Study of some electronics properties of new superconductor Sr2VO3FeAs in ground state

    Directory of Open Access Journals (Sweden)

    M Majidiyan

    2010-09-01

    Full Text Available In this paper, some electronics properties of new superconductor Sr2VO3FeAs, such as density of states, band structure, density of electron cloud and bound lengths in the ground state have been calculated. According to N(Ef in ground state CV/T value has been estimated. The calculations were performed in the framework of density functional theory (DFT, using the full potential linearized augmented plane wave (FP-LAPW method with the general gradient approximation (GGA.

  12. Variational description of continuum states in terms of integral relations

    International Nuclear Information System (INIS)

    Kievsky, A.; Viviani, M.; Barletta, Paolo; Romero-Redondo, C.; Garrido, E.

    2010-01-01

    Two integral relations derived from the Kohn variational principle (KVP) are used for describing scattering states. In usual applications the KVP requires the explicit form of the asymptotic behavior of the scattering wave function. This is not the case when the integral relations are applied since, due to their short-range nature, the only condition for the scattering wave function Ψ is that it be the solution of (H-E)Ψ=0 in the internal region. Several examples are analyzed for the computation of phase shifts from bound-state-type wave functions or, in the case of the scattering of charged particles, it is possible to obtain phase shifts using free asymptotic conditions. As a final example we discuss the use of the integral relations in the case of the hyperspherical adiabatic method.

  13. Ground and Satellite Observations of ULF Waves Artificially Produced by HAARP

    Science.gov (United States)

    Chang, C.; Labenski, J.; Shroff, H.; Doxas, I.; Papadopoulos, D.; Milikh, G.; Parrot, M.

    2008-12-01

    Modulated ionospheric heating at ULF frequencies using the HAARP heater was performed from April 28 to May 3, 2008 (http://www.haarp.alaska.edu). Simultaneous ground-based ULF measurements were made locally at Gakona, AK and at Lake Ozette, WA that is 2000 km away. The ground-based results showed that ULF amplitudes measured at Gakona are mostly proportional to the electrojet strength above HAARP, indicating electrojet modulation to be the source of the local ULF waves. However, the timing of ULF events recorded at Lake Ozette did not correlated with the electrojet strength at Gakona, indicating that modulation of F region pressure is the more likely source for distant ULF waves. These observations are consistent with the theoretical understanding that ULF waves generated by current modulation are shear Alfven waves propagating along the magnetic field line, thus at high latitude their observations are limited to the vicinity of the heated spot. On the other hand, propagation of ULF waves at significant lateral distances requires generation of magnetosonic waves since they are the only mode that propagates isotropically and can thus couple efficiently in the Alfvenic duct. In addition to ground-based observations, the DEMETER satellite also provided space measurements of the heating effects during its passes over HAARP. The DEMETER results showed direct detection of HAARP ULF waves at 0.1 Hz. Moreover, density dips were observed every time HAARP was operated at CW mode, which provides clear evidence of duct formation by direct HF heating at F peak. Details of these results will be presented at the meeting. We would like to acknowledge the support provided by the HAARP facility during our ULF experiments.

  14. Multi-configurational explicitly correlated wave functions for the study of confined many electron atoms

    International Nuclear Information System (INIS)

    Sarsa, A; Buendía, E; Gálvez, F J

    2016-01-01

    Explicitly correlated wave functions to study confined atoms under impenetrable spherical walls have been obtained. Configuration mixing and a correlation factor are included in the variational ansatz. The behaviors of the ground state and some low-lying excited states of He, Be, B and C atoms with the confinement size are analyzed. Level crossing with confinement is found for some cases. This effect is analyzed in terms of the single particle energy of the occupied orbitals. The multi-configuration parameterized optimized effective potential method is employed with a cut-off factor to account for Dirichlet boundary conditions. The variational Monte Carlo method is used to deal with explicitly correlated wave functions. (paper)

  15. Numerical simulations of oscillating soliton stars: Excited states in spherical symmetry and ground state evolutions in 3D

    International Nuclear Information System (INIS)

    Balakrishna, Jayashree; Bondarescu, Ruxandra; Daues, Gregory; Bondarescu, Mihai

    2008-01-01

    Excited state soliton stars are studied numerically for the first time. The stability of spherically symmetric S-branch excited state oscillatons under radial perturbations is investigated using a 1D code. We find that these stars are inherently unstable either migrating to the ground state or collapsing to black holes. Higher excited state configurations are observed to cascade through intermediate excited states during their migration to the ground state. This is similar to excited state boson stars [J. Balakrishna, E. Seidel, and W.-M. Suen, Phys. Rev. D 58, 104004 (1998).]. Ground state oscillatons are then studied in full 3D numerical relativity. Finding the appropriate gauge condition for the dynamic oscillatons is much more challenging than in the case of boson stars. Different slicing conditions are explored, and a customized gauge condition that approximates polar slicing in spherical symmetry is implemented. Comparisons with 1D results and convergence tests are performed. The behavior of these stars under small axisymmetric perturbations is studied and gravitational waveforms are extracted. We find that the gravitational waves damp out on a short time scale, enabling us to obtain the complete waveform. This work is a starting point for the evolution of real scalar field systems with arbitrary symmetries

  16. Variational methods for field theories

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Menahem, S.

    1986-09-01

    Four field theory models are studied: Periodic Quantum Electrodynamics (PQED) in (2 + 1) dimensions, free scalar field theory in (1 + 1) dimensions, the Quantum XY model in (1 + 1) dimensions, and the (1 + 1) dimensional Ising model in a transverse magnetic field. The last three parts deal exclusively with variational methods; the PQED part involves mainly the path-integral approach. The PQED calculation results in a better understanding of the connection between electric confinement through monopole screening, and confinement through tunneling between degenerate vacua. This includes a better quantitative agreement for the string tensions in the two approaches. Free field theory is used as a laboratory for a new variational blocking-truncation approximation, in which the high-frequency modes in a block are truncated to wave functions that depend on the slower background modes (Boron-Oppenheimer approximation). This ''adiabatic truncation'' method gives very accurate results for ground-state energy density and correlation functions. Various adiabatic schemes, with one variable kept per site and then two variables per site, are used. For the XY model, several trial wave functions for the ground state are explored, with an emphasis on the periodic Gaussian. A connection is established with the vortex Coulomb gas of the Euclidean path integral approach. The approximations used are taken from the realms of statistical mechanics (mean field approximation, transfer-matrix methods) and of quantum mechanics (iterative blocking schemes). In developing blocking schemes based on continuous variables, problems due to the periodicity of the model were solved. Our results exhibit an order-disorder phase transition. The transfer-matrix method is used to find a good (non-blocking) trial ground state for the Ising model in a transverse magnetic field in (1 + 1) dimensions.

  17. Ground states of a spin-boson model

    International Nuclear Information System (INIS)

    Amann, A.

    1991-01-01

    Phase transition with respect to ground states of a spin-boson Hamiltonian are investigated. The spin-boson model under discussion consists of one spin and infinitely many bosons with a dipole-type coupling. It is shown that the order parameter of the model vanishes with respect to arbitrary ground states if it vanishes with respect to ground states obtained as (biased) temperature to zero limits of thermic equilibrium states. The ground states of the latter special type have been investigated by H. Spohn. Spohn's respective phase diagrams are therefore valid for arbitrary ground states. Furthermore, disjointness of ground states in the broken symmetry regime is examined

  18. Probing the 8He ground state via the 8He(p,t)6He reaction

    International Nuclear Information System (INIS)

    Keeley, N.; Skaza, F.; Lapoux, V.; Alamanos, N.; Auger, F.; Beaumel, D.; Becheva, E.; Blumenfeld, Y.; Delaunay, F.; Drouart, A.; Gillibert, A.; Giot, L.; Kemper, K.W.; Nalpas, L.; Pakou, A.; Pollacco, E.C.; Raabe, R.; Roussel-Chomaz, P.; Rusek, K.; Scarpaci, J.-A.; Sida, J.-L.; Stepantsov, S.; Wolski, R.

    2007-01-01

    The weakly-bound 8 He nucleus exhibits a neutron halo or thick neutron skin and is generally considered to have an α+4n structure in its ground state, with the four valence neutrons each occupying 1p 3/2 states outside the α core. The 8 He(p,t) 6 He reaction is a sensitive probe of the ground state structure of 8 He, and we present a consistent analysis of new and existing data for this reaction at incident energies of 15.7 and 61.3A MeV, respectively. Our results are incompatible with the usual assumption of a pure (1p 3/2 ) 4 structure and suggest that other configurations such as (1p 3/2 ) 2 (1p 1/2 ) 2 may be present with significant probability in the ground state wave function of 8 He

  19. Multiple scroll wave chimera states

    Science.gov (United States)

    Maistrenko, Volodymyr; Sudakov, Oleksandr; Osiv, Oleksiy; Maistrenko, Yuri

    2017-06-01

    We report the appearance of three-dimensional (3D) multiheaded chimera states that display cascades of self-organized spatiotemporal patterns of coexisting coherence and incoherence. We demonstrate that the number of incoherent chimera domains can grow additively under appropriate variations of the system parameters generating thereby head-adding cascades of the scroll wave chimeras. The phenomenon is derived for the Kuramoto model of N 3 identical phase oscillators placed in the unit 3D cube with periodic boundary conditions, parameters being the coupling radius r and phase lag α. To obtain the multiheaded chimeras, we perform the so-called `cloning procedure' as follows: choose a sample single-headed 3D chimera state, make appropriate scale transformation, and put some number of copies of them into the unit cube. After that, start numerical simulations with slightly perturbed initial conditions and continue them for a sufficiently long time to confirm or reject the state existence and stability. In this way it is found, that multiple scroll wave chimeras including those with incoherent rolls, Hopf links and trefoil knots admit this sort of multiheaded regeneration. On the other hand, multiple 3D chimeras without spiral rotations, like coherent and incoherent balls, tubes, crosses, and layers appear to be unstable and are destroyed rather fast even for arbitrarily small initial perturbations.

  20. Local Density of States in a d-wave Superconductor with Stripe-Like Modulations and a Strong Impurity

    OpenAIRE

    Chen, Hong-Yi; Ting, C. S.

    2003-01-01

    Using an effective Hamiltonian with d-wave superconductivity (dSC) and competing antiferromagnetic (AF) interactions, we show that weak and one-dimensionally modulated dSC, spin density wave (SDW) and charge density wave (CDW) could coexist in the ground state configuration. With proper parameters, the SDW order exhibits a period of 8a, while for dSC and CDW orders the period is 4a. The local density of states (LDOS), which probing the behavior of quasiparticle excitations, is found to have t...

  1. Variational formulation of covariant eikonal theory for vector waves

    International Nuclear Information System (INIS)

    Kaufman, A.N.; Ye, H.; Hui, Y.

    1986-10-01

    The eikonal theory of wave propagation is developed by means of a Lorentz-covariant variational principle, involving functions defined on the natural eight-dimensional phase space of rays. The wave field is a four-vector representing the electromagnetic potential, while the medium is represented by an anisotropic, dispersive nonuniform dielectric tensor D/sup μν/(k,x). The eikonal expansion yields, to lowest order, the Hamiltonian ray equations, which define the Lagrangian manifold k(x), and the wave-action conservation law, which determines the wave-amplitude transport along the rays. The first-order contribution to the variational principle yields a concise expression for the transport of the polarization phase. The symmetry between k-space and x-space allows for a simple implementation of the Maslov transform, which avoids the difficulties of caustic singularities

  2. Analysis of seismic waves and strong ground motion

    International Nuclear Information System (INIS)

    Simpson, I.C.; Sutton, R.

    1976-10-01

    A number of Western USA earthquake acceleration-time histories concerning events of magnitude less than 6 are considered and their Fourier spectra calculated. An analysis of some of the simpler types of seismic wave is given in order to consider the generation of a spatially dependent acceleration-time history suitable for input into a soil-structure program of analysis. Such an acceleration-time history is required by a comprehensive analysis of soil-structure interaction since the conventionally assumed model of vertically propagating seismic waves, which give rise to three spatially independent ground motions, can lead to over-conservative estimates of the building response in the high frequency range. The possible application is discussed of a given component of a recorded acceleration-time history to the base of structure under the assumption of surface Rayleigh waves or obliquely incident P and SV bulk waves. (author)

  3. Status of advanced ground-based laser interferometers for gravitational-wave detection

    Science.gov (United States)

    Dooley, K. L.; Akutsu, T.; Dwyer, S.; Puppo, P.

    2015-05-01

    Ground-based laser interferometers for gravitational-wave (GW) detection were first constructed starting 20 years ago and as of 2010 collection of several years’ worth of science data at initial design sensitivities was completed. Upgrades to the initial detectors together with construction of brand new detectors are ongoing and feature advanced technologies to improve the sensitivity to GWs. This conference proceeding provides an overview of the common design features of ground-based laser interferometric GW detectors and establishes the context for the status updates of each of the four gravitational-wave detectors around the world: Advanced LIGO, Advanced Virgo, GEO 600 and KAGRA.

  4. GPM GROUND VALIDATION CONICAL SCANNING MILLIMETER-WAVE IMAGING RADIOMETER (COSMIR) GCPEX V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The GPM Ground Validation Conical Scanning Millimeter-wave Imaging Radiometer (COSMIR) GCPEx dataset used the Conical Scanning Millimeter-wave Imaging Radiometer...

  5. Site Classification using Multichannel Channel Analysis of Surface Wave (MASW) method on Soft and Hard Ground

    Science.gov (United States)

    Ashraf, M. A. M.; Kumar, N. S.; Yusoh, R.; Hazreek, Z. A. M.; Aziman, M.

    2018-04-01

    Site classification utilizing average shear wave velocity (Vs(30) up to 30 meters depth is a typical parameter. Numerous geophysical methods have been proposed for estimation of shear wave velocity by utilizing assortment of testing configuration, processing method, and inversion algorithm. Multichannel Analysis of Surface Wave (MASW) method is been rehearsed by numerous specialist and professional to geotechnical engineering for local site characterization and classification. This study aims to determine the site classification on soft and hard ground using MASW method. The subsurface classification was made utilizing National Earthquake Hazards Reduction Program (NERHP) and international Building Code (IBC) classification. Two sites are chosen to acquire the shear wave velocity which is in the state of Pulau Pinang for soft soil and Perlis for hard rock. Results recommend that MASW technique can be utilized to spatially calculate the distribution of shear wave velocity (Vs(30)) in soil and rock to characterize areas.

  6. Variational lower bound on the scattering length

    International Nuclear Information System (INIS)

    Rosenberg, L.; Spruch, L.

    1975-01-01

    The scattering length A characterizes the zero-energy scattering of one system by another. It was shown some time ago that a variational upper bound on A could be obtained using methods, of the Rayleigh-Ritz type, which are commonly employed to obtain upper bounds on energy eigenvalues. Here we formulate a method for obtaining a variational lower bound on A. Once again the essential idea is to express the scattering length as a variational estimate plus an error term and then to reduce the problem of bounding the error term to one involving bounds on energy eigenvalues. In particular, the variational lower bound on A is rigorously established provided a certin modified Hamiltonian can be shown to have no discrete states lying below the level of the continuum threshold. It is unfortunately true that necessary conditions for the existence of bound states are not available for multiparticle systems in general. However, in the case of positron-atom scattering the adiabatic approximation can be introduced as an (essentially) solvable comparison problem to rigorously establish the nonexistence of bound states of the modified Hamiltonian. It has recently been shown how the validity of the variational upper bound on A can be maintained when the target ground-state wave function is imprecisely known. Similar methods can be used to maintain the variational lower bound on A. Since the bound is variational, the error in the calculated scattering length will be of second order in the error in the wave function. The use of the adiabatic approximation in the present context places no limitation in principle on the accuracy achievable

  7. Status of advanced ground-based laser interferometers for gravitational-wave detection

    International Nuclear Information System (INIS)

    Dooley, K L; Akutsu, T; Dwyer, S; Puppo, P

    2015-01-01

    Ground-based laser interferometers for gravitational-wave (GW) detection were first constructed starting 20 years ago and as of 2010 collection of several years’ worth of science data at initial design sensitivities was completed. Upgrades to the initial detectors together with construction of brand new detectors are ongoing and feature advanced technologies to improve the sensitivity to GWs. This conference proceeding provides an overview of the common design features of ground-based laser interferometric GW detectors and establishes the context for the status updates of each of the four gravitational-wave detectors around the world: Advanced LIGO, Advanced Virgo, GEO 600 and KAGRA. (paper)

  8. Characteristics of the magnetohydrodynamic waves observed in the earth's magnetosphere and on the ground

    International Nuclear Information System (INIS)

    Kuwashima, M.; Fujita, S.

    1989-01-01

    Current research topics on MHD waves in the earth's magnetosphere and on the ground are summarized. Upstream waves in the earth's foreshock region and their transmission into and propagation through the magnetosphere are discussed in the context of relationships of Pc3 magnetic pulsations on the ground. The characteristics of ssc-associated magnetic pulsations are considered, and instabilities with the hot plasma in the ring current in the magnetosphere are addressed in the context of the relationships of compressional Pc 4-5 waves. The characteristics of Pi2 magnetic pulsations are examined, and the role of the ionosphere on the modifications of MHD waves is addressed

  9. Distributed state machine supervision for long-baseline gravitational-wave detectors

    International Nuclear Information System (INIS)

    Rollins, Jameson Graef

    2016-01-01

    The Laser Interferometer Gravitational-wave Observatory (LIGO) consists of two identical yet independent, widely separated, long-baseline gravitational-wave detectors. Each Advanced LIGO detector consists of complex optical-mechanical systems isolated from the ground by multiple layers of active seismic isolation, all controlled by hundreds of fast, digital, feedback control systems. This article describes a novel state machine-based automation platform developed to handle the automation and supervisory control challenges of these detectors. The platform, called Guardian, consists of distributed, independent, state machine automaton nodes organized hierarchically for full detector control. User code is written in standard Python and the platform is designed to facilitate the fast-paced development process associated with commissioning the complicated Advanced LIGO instruments. While developed specifically for the Advanced LIGO detectors, Guardian is a generic state machine automation platform that is useful for experimental control at all levels, from simple table-top setups to large-scale multi-million dollar facilities.

  10. Distributed state machine supervision for long-baseline gravitational-wave detectors

    Energy Technology Data Exchange (ETDEWEB)

    Rollins, Jameson Graef, E-mail: jameson.rollins@ligo.org [LIGO Laboratory, California Institute of Technology, Pasadena, California 91125 (United States)

    2016-09-15

    The Laser Interferometer Gravitational-wave Observatory (LIGO) consists of two identical yet independent, widely separated, long-baseline gravitational-wave detectors. Each Advanced LIGO detector consists of complex optical-mechanical systems isolated from the ground by multiple layers of active seismic isolation, all controlled by hundreds of fast, digital, feedback control systems. This article describes a novel state machine-based automation platform developed to handle the automation and supervisory control challenges of these detectors. The platform, called Guardian, consists of distributed, independent, state machine automaton nodes organized hierarchically for full detector control. User code is written in standard Python and the platform is designed to facilitate the fast-paced development process associated with commissioning the complicated Advanced LIGO instruments. While developed specifically for the Advanced LIGO detectors, Guardian is a generic state machine automation platform that is useful for experimental control at all levels, from simple table-top setups to large-scale multi-million dollar facilities.

  11. Length and activation dependent variations in muscle shear wave speed

    International Nuclear Information System (INIS)

    Chernak, L A; DeWall, R J; Lee, K S; Thelen, D G

    2013-01-01

    Muscle stiffness is known to vary as a result of a variety of disease states, yet current clinical methods for quantifying muscle stiffness have limitations including cost and availability. We investigated the capability of shear wave elastography (SWE) to measure variations in gastrocnemius shear wave speed induced via active contraction and passive stretch. Ten healthy young adults were tested. Shear wave speeds were measured using a SWE transducer positioned over the medial gastrocnemius at ankle angles ranging from maximum dorsiflexion to maximum plantarflexion. Shear wave speeds were also measured during voluntary plantarflexor contractions at a fixed ankle angle. Average shear wave speed increased significantly from 2.6 to 5.6 m s –1 with passive dorsiflexion and the knee in an extended posture, but did not vary with dorsiflexion when the gastrocnemius was shortened in a flexed knee posture. During active contractions, shear wave speed monotonically varied with the net ankle moment generated, reaching 8.3 m s –1 in the maximally contracted condition. There was a linear correlation between shear wave speed and net ankle moment in both the active and passive conditions; however, the slope of this linear relationship was significantly steeper for the data collected during passive loading conditions. The results show that SWE is a promising approach for quantitatively assessing changes in mechanical muscle loading. However, the differential effect of active and passive loading on shear wave speed makes it important to carefully consider the relevant loading conditions in which to use SWE to characterize in vivo muscle properties. (paper)

  12. Evaluation of upper and lower bounds to energy eigenvalues in Shoenberg's perturbation-theory ground state by means of partitioning technique

    International Nuclear Information System (INIS)

    Logrado, P.G.; Vianna, J.D.M.

    Upper and lower bounds for the energy eigenvalues is Schoenberg's perturbation-theory ground state are studied. After a review of the characteristic features of the partitioning techniques the perturbative expansion proposed by Schoenberg is generated from an exact operator equation. The upper and lower bounds for the ground state eigenvalue are derived by using reaction and wave operators concepts, the bracketing function and operator inequalities. (Author) [pt

  13. Variational study of the pair hopping model

    International Nuclear Information System (INIS)

    Fazekas, P.

    1990-01-01

    We study the ground state of a Hamiltonian introduced by Kolb and Penson for modelling situations in which small electron pairs are formed. The Hamiltonian consists of a tight binding band term, and a term describing the nearest neighbour hopping of electron pairs. We give a Gutzwiller-type variational treatment, first with a single-parameter Ansatz treated in the single site Gutzwiller approximation, and then with more complicated trial wave functions, and an improved Gutzwiller approximation. The calculation yields a transition from a partially paired normal state, in which the spin susceptibility has a diminished value, into a fully paired state. (author). 16 refs, 2 figs

  14. Transferrin variation and evolution of Canadian barren-ground caribou

    Directory of Open Access Journals (Sweden)

    Knut H. Røed

    1990-09-01

    Full Text Available Blood samples were obtained from 95 barren-ground caribou (Rangifer tarandus groenlandicus of the Beverly herd in Northwest Territories, Canada. Polyacrylamid gel electrophoresis was used to score for genetic variation in the locus coding for transferrin. The pattern of allele frequency distribution are compared with previously reported values of Eurasian tundra reindeer (R.t. tarandus, Alaska caribou (R.t. granti, Peary caribou (R.t. pearyi, and Svalbard reindeer (R.t. platyrhynchus. In the Beverly herd a total of 21 different transferrin alleles were detected. The amount of genetic variation was higher in the Canadian barren-ground caribou than what has been detected in other subspecies of reindeer/caribou. Highly gene-tical differences in the allele frequencies were detected between the Canadian barren-ground caribou and the other subspecies. The genetic identity analyses indicates approximately the same amount of genetic differentiation when the Canadian barren-ground caribou are compared with Alaska caribou as with the Peary caribou. The allele frequency pattern could be explained by a possible origin of the Canadian barren-ground caribou from an ancestral population which was genetical influenced by animals surviving the We-ichselian glaciation in refugia both in high Arctic, in Beringia, and south of the ice sheet.

  15. Impact of Tidal Level Variations on Wave Energy Absorption at Wave Hub

    Directory of Open Access Journals (Sweden)

    Valeria Castellucci

    2016-10-01

    Full Text Available The energy absorption of the wave energy converters (WEC characterized by a limited stroke length —like the point absorbers developed at Uppsala University—depends on the sea level variation at the deployment site. In coastal areas characterized by high tidal ranges, the daily energy production of the generators is not optimal. The study presented in this paper quantifies the effects of the changing sea level at the Wave Hub test site, located at the south-west coast of England. This area is strongly affected by tides: the tidal height calculated as the difference between the Mean High Water Spring and the Mean Low Water Spring in 2014 was about 6.6 m. The results are obtained from a hydro-mechanic model that analyzes the behaviour of the point absorber at the Wave Hub, taking into account the sea state occurrence scatter diagram and the tidal time series at the site. It turns out that the impact of the tide decreases the energy absorption by 53%. For this reason, the need for a tidal compensation system to be included in the design of the WEC becomes compelling. The economic advantages are evaluated for different scenarios: the economic analysis proposed within the paper allows an educated guess to be made on the profits. The alternative of extending the stroke length of the WEC is investigated, and the gain in energy absorption is estimated.

  16. Morphology of low-frequency waves in the solar wind and their relation to ground pulsations

    International Nuclear Information System (INIS)

    Odera, T.J.; Stuart, W.F.

    1986-01-01

    Three classes of low frequency waves (period range 20 to 80 s) were identified using data from the UCLA fluxgate magnetometer experiment on board the ISEE 2 spacecraft. These are continuous pulsations similar in type to Pc 3, band-limited oscillations distinguished by mixed period fluctuations, and relatively isolated wave bundles. The waves were preferentially observed when the interplanetary magnetic field (IMF) direction was sunward and were most common when the cone angle, i.e. the angle between IMF and the Sun-Earth line (thetasub(xB)) was often between 15 deg and 45 deg. Their frequency is proportional to the IMF magnitude. Comparison between the waves observed on board the ISEE 2 spacecraft and the Pc 3-4 recorded simultaneously at a mid-latitude ground station, Oulu (L = 4.5), showed that similarity of spectra of the waves in the spacecraft and on the ground was very rare and that correspondence between the events in space and on the ground was extremely low. (author)

  17. Shear wave velocity-based evaluation and design of stone column improved ground for liquefaction mitigation

    Science.gov (United States)

    Zhou, Yanguo; Sun, Zhengbo; Chen, Jie; Chen, Yunmin; Chen, Renpeng

    2017-04-01

    The evaluation and design of stone column improvement ground for liquefaction mitigation is a challenging issue for the state of practice. In this paper, a shear wave velocity-based approach is proposed based on the well-defined correlations of liquefaction resistance (CRR)-shear wave velocity ( V s)-void ratio ( e) of sandy soils, and the values of parameters in this approach are recommended for preliminary design purpose when site specific values are not available. The detailed procedures of pre- and post-improvement liquefaction evaluations and stone column design are given. According to this approach, the required level of ground improvement will be met once the target V s of soil is raised high enough (i.e., no less than the critical velocity) to resist the given earthquake loading according to the CRR- V s relationship, and then this requirement is transferred to the control of target void ratio (i.e., the critical e) according to the V s- e relationship. As this approach relies on the densification of the surrounding soil instead of the whole improved ground and is conservative by nature, specific considerations of the densification mechanism and effect are given, and the effects of drainage and reinforcement of stone columns are also discussed. A case study of a thermal power plant in Indonesia is introduced, where the effectiveness of stone column improved ground was evaluated by the proposed V s-based method and compared with the SPT-based evaluation. This improved ground performed well and experienced no liquefaction during subsequent strong earthquakes.

  18. Frequency variations of gravity waves interacting with a time-varying tide

    Energy Technology Data Exchange (ETDEWEB)

    Huang, C.M.; Zhang, S.D.; Yi, F.; Huang, K.M.; Gan, Q.; Gong, Y. [Wuhan Univ., Hubei (China). School of Electronic Information; Ministry of Education, Wuhan, Hubei (China). Key Lab. of Geospace Environment and Geodesy; State Observatory for Atmospheric Remote Sensing, Wuhan, Hubei (China); Zhang, Y.H. [Nanjing Univ. of Information Science and Technology (China). College of Hydrometeorolgy

    2013-11-01

    Using a nonlinear, 2-D time-dependent numerical model, we simulate the propagation of gravity waves (GWs) in a time-varying tide. Our simulations show that when aGW packet propagates in a time-varying tidal-wind environment, not only its intrinsic frequency but also its ground-based frequency would change significantly. The tidal horizontal-wind acceleration dominates the GW frequency variation. Positive (negative) accelerations induce frequency increases (decreases) with time. More interestingly, tidal-wind acceleration near the critical layers always causes the GW frequency to increase, which may partially explain the observations that high-frequency GW components are more dominant in the middle and upper atmosphere than in the lower atmosphere. The combination of the increased ground-based frequency of propagating GWs in a time-varying tidal-wind field and the transient nature of the critical layer induced by a time-varying tidal zonal wind creates favorable conditions for GWs to penetrate their originally expected critical layers. Consequently, GWs have an impact on the background atmosphere at much higher altitudes than expected, which indicates that the dynamical effects of tidal-GW interactions are more complicated than usually taken into account by GW parameterizations in global models.

  19. Basin-edge generated Rayleigh waves in the Almaty basin and corresponding consequences for ground motion amplification

    Science.gov (United States)

    Pilz, Marco; Parolai, Stefano; Petrovic, Bojana; Silacheva, Natalya; Abakanov, Tanatkan; Orunbaev, Sagynbek; Moldobekov, Bolot

    2018-04-01

    During the past two centuries, several large earthquakes have caused extensive damages in the city of Almaty in Kazakhstan. Increasing the preparedness for future events, the definition of the optimal engineering designs for civil structures and the corresponding mitigation of earthquake risks involves the accomplishment of site response studies. To this regard, a temporary seismological network of 15 stations was installed in the city aiming at the accurate identification of local variations of site response at different locations. As the city is settled on a deep sediment-filled plain with laterally strongly varying thicknesses, bound to the south by the Tien-Shan mountain range, the city might face important site effects: large amplification and significant increase of shaking duration. In addition, surface waves in the low-frequency range around and slightly higher than the fundamental resonance frequency, which could be generated at the boundaries of the basin, can carry a large amount of energy. In turn, this will influence both the spatial distribution of the level of amplification and the temporal lengthening of ground motion significantly. For quantifying these effects, we apply complex trace analysis, which uses the instantaneous polarization characteristics of the seismic signal for separating waves arriving at a single site from different directions. In this way, secondary surface waves originating at various sites along the edge of the Almaty basin can be identified as well as their generation regions. After having assessed 1-D amplification effects with well-established techniques like the standard spectral ratio and the horizontal-to-vertical spectral ratio techniques, the results further indicate that thick layers of soft clay deposits and the 3-D structure of the basin give rise to lengthening of ground motion and high amplification values at low frequencies around 0.2 Hz. The steep structure of the sediment-bedrock interface at the southern edge

  20. Solving ground eigenvalue and eigenfunction of spheroidal wave equation at low frequency by supersymmetric quantum mechanics method

    Institute of Scientific and Technical Information of China (English)

    Tang Wen-Lin; Tian Gui-Hua

    2011-01-01

    The spheroidal wave functions are found to have extensive applications in many branches of physics and mathematics. We use the perturbation method in supersymmetric quantum mechanics to obtain the analytic ground eigenvalue and the ground eigenfunction of the angular spheroidal wave equation at low frequency in a series form. Using this approach, the numerical determinations of the ground eigenvalue and the ground eigenfunction for small complex frequencies are also obtained.

  1. Symmetry-projected variational approach to the one-dimensional Hubbard model

    International Nuclear Information System (INIS)

    Schmid, K.W.; Dahm, T.; Margueron, J.; Muether, H.

    2005-01-01

    We apply a variational method devised for the nuclear many-body problem to the one-dimensional Hubbard model with nearest neighbor hopping and periodic boundary conditions. The test wave function consist for each state out of a single Hartree-Fock determinant mixing all the sites (or momenta) as well as the spin projections of the electrons. Total spin and linear momentum are restored by projection methods before the variation. It is demonstrated that this approach reproduces the results of exact diagonalizations for half-filled N=12 and N=14 lattices not only for the energies and occupation numbers of the ground but also of the lowest excited states rather well. Furthermore, a system of ten electrons in an N=12 lattice is investigated and, finally, an N=30 lattice is studied. In addition to energies and occupation numbers we present the spectral functions computed with the help of the symmetry-projected wave functions as well

  2. Ground states of quantum spin systems

    International Nuclear Information System (INIS)

    Bratteli, Ola; Kishimoto, Akitaka; Robinson, D.W.

    1978-07-01

    The authors prove that ground states of quantum spin systems are characterized by a principle of minimum local energy and that translationally invariant ground states are characterized by the principle of minimum energy per unit volume

  3. dc Resistivity of Quantum Critical, Charge Density Wave States from Gauge-Gravity Duality.

    Science.gov (United States)

    Amoretti, Andrea; Areán, Daniel; Goutéraux, Blaise; Musso, Daniele

    2018-04-27

    In contrast to metals with weak disorder, the resistivity of weakly pinned charge density waves (CDWs) is not controlled by irrelevant processes relaxing momentum. Instead, the leading contribution is governed by incoherent, diffusive processes which do not drag momentum and can be evaluated in the clean limit. We compute analytically the dc resistivity for a family of holographic charge density wave quantum critical phases and discuss its temperature scaling. Depending on the critical exponents, the ground state can be conducting or insulating. We connect our results to dc electrical transport in underdoped cuprate high T_{c} superconductors. We conclude by speculating on the possible relevance of unstable, semilocally critical CDW states to the strange metallic region.

  4. dc Resistivity of Quantum Critical, Charge Density Wave States from Gauge-Gravity Duality

    Science.gov (United States)

    Amoretti, Andrea; Areán, Daniel; Goutéraux, Blaise; Musso, Daniele

    2018-04-01

    In contrast to metals with weak disorder, the resistivity of weakly pinned charge density waves (CDWs) is not controlled by irrelevant processes relaxing momentum. Instead, the leading contribution is governed by incoherent, diffusive processes which do not drag momentum and can be evaluated in the clean limit. We compute analytically the dc resistivity for a family of holographic charge density wave quantum critical phases and discuss its temperature scaling. Depending on the critical exponents, the ground state can be conducting or insulating. We connect our results to dc electrical transport in underdoped cuprate high Tc superconductors. We conclude by speculating on the possible relevance of unstable, semilocally critical CDW states to the strange metallic region.

  5. Variation of Pressure Waveforms in Measurements of Extracorporeal Shock Wave Lithotripter

    Science.gov (United States)

    Inose, Naoto; Ide, Masao

    1993-05-01

    In this paper, we describe measurement of variation in pressure waveforms of the acoustic field of an extra-corporeal shock-wave lithotripter (ESWL). Variations in the measured acoustic fields and pressure waveform of an underwater spark-gap-type ESWL with an exhausted spark plug electrode have been reported by researchers using crystal sensors. If the ESWL spark plugs become exhausted, patients feel pain during kidney, biliary stone disintegration. We studied the relationship between exhaustion of electrodes and the variation of pressure waveforms and shock-wave fields of the ESWL using a newly developed hydrophone.

  6. Competing p-wave orders

    International Nuclear Information System (INIS)

    Donos, Aristomenis; Gauntlett, Jerome P; Pantelidou, Christiana

    2014-01-01

    We construct electrically charged, asymptotically AdS 5 black hole solutions that are dual to d = 4 CFTs in a superfluid phase with either p-wave or (p + ip)-wave order. The two types of black holes have non-vanishing charged two-form in the bulk and appear at the same critical temperature in the unbroken phase. Both the p-wave and the (p + ip)-wave phase can be thermodynamically preferred, depending on the mass and charge of the two-form, and there can also be first order transitions between them. The p-wave black holes have a helical structure and some of them exhibit the phenomenon of pitch inversion as the temperature is decreased. Both the p-wave and the (p + ip)-wave black holes have zero entropy density ground states at zero temperature and we identify some new ground states which exhibit scaling symmetry, including a novel scenario for the emergence of conformal symmetry in the IR. (paper)

  7. Spin-polarized ground state and exact quantization at ν=5/2

    Science.gov (United States)

    Pan, Wei

    2002-03-01

    The nature of the even-denominator fractional quantum Hall effect at ν=5/2 remains elusive, in particular, its ground state spin-polarization. An earlier, so-called "hollow core" model arrived at a spin-unpolarized wave function. The more recent calculations based on a model of BCS-like pairing of composite fermions, however, suggest that its ground state is spin-polarized. In this talk, I will first review the earlier experiments and then present our recent experimental results showing evidence for a spin-polarized state at ν=5/2. Our ultra-low temperature experiments on a high quality sample established the fully developed FQHE state at ν=5/2 as well as at ν=7/3 and 8/3, manifested by a vanishing R_xx and exact quantization of the Hall plateau. The tilted field experiments showed that the added in-plane magnetic fields not only destroyed the FQHE at ν=5/2, as seen before, but also induced an electrical anisotropy, which is now interpreted as a phase transition from a paired, spin-polarized ν=5/2 state to a stripe phase, not unlike the ones at ν=9/2, 11/2, etc in the N > 1 higher Landau levels. Furthermore, in the experiments on the heterojunction insulated-gate field-effect transistors (HIGFET) at dilution refrigerator temperatures, a strong R_xx minimum and a concomitant developing Hall plateau were observed at ν=5/2 in a magnetic field as high as 12.6 Tesla. This and the subsequent density dependent studies of its energy gap largely rule out a spin-singlet state and point quite convincingly towards a spin-polarized ground state at ν=5/2.

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

    International Nuclear Information System (INIS)

    Shrivastava, Keshav N.

    2010-01-01

    The Laughlin's wave function is found to be the zero-energy ground state of a δ-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 ψ 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.

  9. Improved techniques for outgoing wave variational principle calculations of converged state-to-state transition probabilities for chemical reactions

    Science.gov (United States)

    Mielke, Steven L.; Truhlar, Donald G.; Schwenke, David W.

    1991-01-01

    Improved techniques and well-optimized basis sets are presented for application of the outgoing wave variational principle to calculate converged quantum mechanical reaction probabilities. They are illustrated with calculations for the reactions D + H2 yields HD + H with total angular momentum J = 3 and F + H2 yields HF + H with J = 0 and 3. The optimization involves the choice of distortion potential, the grid for calculating half-integrated Green's functions, the placement, width, and number of primitive distributed Gaussians, and the computationally most efficient partition between dynamically adapted and primitive basis functions. Benchmark calculations with 224-1064 channels are presented.

  10. Complex Kohn variational principle for two-nucleon bound-state and scattering with the tensor potential

    International Nuclear Information System (INIS)

    Araujo Junior, C.F. de; Adhikari, S.K.; Tomio, L.

    1993-10-01

    Complex Kohn variational principle is applied to the numerical solution of the fully off-shell Lippmann-Schwinger equation for nucleon-nucleon scattering for various partial waves including the coupled 3 S 1 - 3 D 1 channel. Analytic expressions are obtained for all the integrals in the method for a suitable choice of expansion functions. Calculations with the partial waves 1 S 0 , 1 P 1 , 1 D 2 , and 3 S 1 - 3 D 1 of the Reid soft core potential show that the method converges faster than other solution schemes not only for the phase shift but also for the off-shell t matrix elements. It is also shown that its is trivial to modify this variational principle in order to make it suitable for bound-stage calculations. The bound-state approach is illustrated for the 3 S 1 - 3 D 1 channel of the Reid soft-core potential for calculating the deuteron binding, wave function and the D state asymptotic parameters. (author)

  11. Vibrational frequencies and dephasing times in excited electronic states by femtosecond time-resolved four-wave mixing

    Science.gov (United States)

    Joo, Taiha; Albrecht, A. C.

    1993-06-01

    Time-resolved degenerate four-wave mixing (TRDFWM) for an electronically resonant system in a phase-matching configuration that measures population decay is reported. Because the spectral width of input light exceeds the vibrational Bohr frequency of a strong Raman active mode, the vibrational coherence produces strong oscillations in the TRDFWM signal together with the usual population decay from the excited electronic state. The data are analyzed in terms of a four-level system: ground and excited electronic states each split by a vibrational quantum of a Raman active mode. Absolute frequencies and their dephasing times of the vibrational modes at ≈590 cm -1 are obtained for the excited as well as the ground electronic state. The vibrational dephasing rate in the excited electronic state is about an order of magnitude faster than that in the ground state, the origin of which is speculated upon.

  12. Emergent Ising degrees of freedom above a double-stripe magnetic ground state

    Science.gov (United States)

    Zhang, Guanghua; Flint, Rebecca

    2017-12-01

    Double-stripe magnetism [Q =(π /2 ,π /2 )] has been proposed as the magnetic ground state for both the iron-telluride and BaTi2Sb2O families of superconductors. Double-stripe order is captured within a J1-J2-J3 Heisenberg model in the regime J3≫J2≫J1 . Intriguingly, besides breaking spin-rotational symmetry, the ground-state manifold has three additional Ising degrees of freedom associated with bond ordering. Via their coupling to the lattice, they give rise to an orthorhombic distortion and to two nonuniform lattice distortions with wave vector (π ,π ) . Because the ground state is fourfold degenerate, modulo rotations in spin space, only two of these Ising bond order parameters are independent. Here, we introduce an effective field theory to treat all Ising order parameters, as well as magnetic order, and solve it within a large-N limit. All three transitions, corresponding to the condensations of two Ising bond order parameters and one magnetic order parameter are simultaneous and first order in three dimensions, but lower dimensionality, or equivalently weaker interlayer coupling, and weaker magnetoelastic coupling can split the three transitions, and in some cases allows for two separate Ising phase transitions above the magnetic one.

  13. Cluster expansion of the wavefunction. Calculation of electron correlations in ground and excited states by SAC and SAC CI theories

    International Nuclear Information System (INIS)

    Nakatsuji, H.

    1979-01-01

    The SAC and SAC CI theories are formulated for actual calculations of singlet ground states and their excited states of arbitrary spin multiplicity. Approximations are considered for the variational methods since time-consuming terms are involved. The results of test calculations for singlet states have shown, with much smaller numbers of variables (sizes of the matrices involved), excellent agreement with the full CI and close-to-full CI results. This shows the utility of the SAC theory for ground states and especially of the SAC CI theory for excited states, since the slow convergence of the CI theory is much more critical for excited states than for ground states. (Auth.)

  14. Generalization of the variational principle and the Hohenberg and Kohn theorems for excited states of Fermion systems

    Energy Technology Data Exchange (ETDEWEB)

    Gonis, A., E-mail: gonis@comcast.net

    2017-01-05

    Through the entanglement of a collection of K non-interacting replicas of a system of N interacting Fermions, and making use of the properties of reduced density matrices the variational principle and the theorems of Hohenberg and Kohn are generalized to excited states. The generalization of the variational principle makes use of the natural orbitals of an N-particle density matrix describing the state of lowest energy of the entangled state. The extension of the theorems of Hohenberg and Kohn is based on the ground-state formulation of density functional theory but with a new interpretation of the concept of a ground state: It is the state of lowest energy of a system of KN Fermions that is described in terms of the excited states of the N-particle interacting system. This straightforward implementation of the line of reasoning of ground-state density functional theory to a new domain leads to a unique and logically valid extension of the theory to excited states that allows the systematic treatment of all states in the spectrum of the Hamiltonian of an interacting system. - Highlights: • Use of entanglement in connection with the properties of density matrices. • An anti-symmetric entangled state of order KN expressed in terms of excited states of an interacting N-particle system.

  15. Measurement of Plane-Wave Spectra of Ground Penetrating Radar Antennas

    DEFF Research Database (Denmark)

    Lenler-Eriksen, Hans-Rudolph; Meincke, Peter

    2005-01-01

    The plane-wave transmitting spectrum of a ground penetrating radar (GPR) loop antenna close to the air-soil interface is measured by means of a probe buried in soil. Probe correction is implemented based upon knowledge about the complex permittivity of the soil and the current distribution...

  16. GPM GROUND VALIDATION CONICAL SCANNING MILLIMETER-WAVE IMAGING RADIOMETER (COSMIR) MC3E V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The GPM Ground Validation Conical Scanning Millimeter-wave Imaging Radiometer (COSMIR) MC3E dataset used the Conical Scanning Millimeter-wave Imaging Radiometer...

  17. Hall viscosity of hierarchical quantum Hall states

    Science.gov (United States)

    Fremling, M.; Hansson, T. H.; Suorsa, J.

    2014-03-01

    Using methods based on conformal field theory, we construct model wave functions on a torus with arbitrary flat metric for all chiral states in the abelian quantum Hall hierarchy. These functions have no variational parameters, and they transform under the modular group in the same way as the multicomponent generalizations of the Laughlin wave functions. Assuming the absence of Berry phases upon adiabatic variations of the modular parameter τ, we calculate the quantum Hall viscosity and find it to be in agreement with the formula, given by Read, which relates the viscosity to the average orbital spin of the electrons. For the filling factor ν =2/5 Jain state, which is at the second level in the hierarchy, we compare our model wave function with the numerically obtained ground state of the Coulomb interaction Hamiltonian in the lowest Landau level, and find very good agreement in a large region of the complex τ plane. For the same example, we also numerically compute the Hall viscosity and find good agreement with the analytical result for both the model wave function and the numerically obtained Coulomb wave function. We argue that this supports the notion of a generalized plasma analogy that would ensure that wave functions obtained using the conformal field theory methods do not acquire Berry phases upon adiabatic evolution.

  18. A pair density functional theory utilizing the correlated wave function

    International Nuclear Information System (INIS)

    Higuchi, M; Higuchi, K

    2009-01-01

    We propose a practical scheme for calculating the ground-state pair density (PD) by utilizing the correlated wave function. As the correlated wave function, we adopt a linear combination of the single Slater determinants that are constructed from the solutions of the initial scheme [Higuchi M and Higuchi K 2007 Physica B 387, 117]. The single-particle equation is derived by performing the variational principle within the set of PDs that are constructed from such correlated wave functions. Since the search region of the PD is substantially extended as compared with the initial scheme, it is expected that the present scheme can cover more correlation effects. The single-particle equation is practical, and may be easily applied to actual calculations.

  19. Coulomb Scattering in the Massless Nelson Model III: Ground State Wave Functions and Non-commutative Recurrence Relations

    Science.gov (United States)

    Dybalski, Wojciech; Pizzo, Alessandro

    2018-02-01

    Let $H_{P,\\sigma}$ be the single-electron fiber Hamiltonians of the massless Nelson model at total momentum $P$ and infrared cut-off $\\sigma>0$. We establish detailed regularity properties of the corresponding $n$-particle ground state wave functions $f^n_{P,\\sigma}$ as functions of $P$ and $\\sigma$. In particular, we show that \\[ |\\partial_{P^j}f^{n}_{P,\\sigma}(k_1,\\ldots, k_n)|, \\ \\ |\\partial_{P^j} \\partial_{P^{j'}} f^{n}_{P,\\sigma}(k_1,\\ldots, k_n)| \\leq \\frac{1}{\\sqrt{n!}} \\frac{(c\\lambda_0)^n}{\\sigma^{\\delta_{\\lambda_0}}} \\prod_{i=1}^n\\frac{ \\chi_{[\\sigma,\\kappa)}(k_i)}{|k_i|^{3/2}}, \\] where $c$ is a numerical constant, $\\lambda_0\\mapsto \\delta_{\\lambda_0}$ is a positive function of the maximal admissible coupling constant which satisfies $\\lim_{\\lambda_0\\to 0}\\delta_{\\lambda_0}=0$ and $\\chi_{[\\sigma,\\kappa)}$ is the (approximate) characteristic function of the energy region between the infrared cut-off $\\sigma$ and the ultraviolet cut-off $\\kappa$. While the analysis of the first derivative is relatively straightforward, the second derivative requires a new strategy. By solving a non-commutative recurrence relation we derive a novel formula for $f^n_{P,\\sigma}$ with improved infrared properties. In this representation $\\partial_{P^{j'}}\\partial_{P^{j}}f^n_{P,\\sigma}$ is amenable to sharp estimates obtained by iterative analytic perturbation theory in part II of this series of papers. The bounds stated above are instrumental for scattering theory of two electrons in the Nelson model, as explained in part I of this series.

  20. Studies on Charge Variation and Waves in Dusty Plasmas

    Science.gov (United States)

    Kausik, Siddhartha Sankar

    Plasma and dust grains are both ubiquitous ingredients of the universe. The interplay between them has opened up a new and fascinating research domain, that of dusty plasmas, which contain macroscopic particles of solid matter besides the usual plasma constituents. The research in dusty plasmas received a major boost in the early eighties with Voyager spacecraft observation on the formation of Saturn rings. Dusty plasmas are defined as partially or fully-ionized gases that contain micron-sized particles of electrically charged solid material, either dielectric or conducting. The physics of dusty plasmas has recently been studied intensively because of its importance for a number of applications in space and laboratory plasmas. This thesis presents the experimental studies on charge variation and waves in dusty plasmas. The experimental observations are carried out in two different experimental devices. Three different sets of experiments are carried out in two different experimental devices. Three different sets of experiments are carried out to study the dust charge variation in a filament discharge argon plasma. The dust grains used in these experiments are grains of silver. In another get of experiment, dust acoustic waves are studied in a de glow discharge argon plasma. Alumina dust grains are sprinkled in this experiment. The diagnostic tools used in these experiments are Langmuir probe and Faraday cup. The instruments used in these experiments are electrometer, He-Ne laser and charge coupled device (CCD) camera. Langmuir probe is used to measure plasma parameters, while Faraday cup and electrometer are used to measure very low current (~pA) carried by a collimated dust beam. He-Ne laser illuminates the dust grains and CCD camera is used to capture the images of dust acoustic waves. Silver dust grains are produced in the dust chamber by gas-evaporation technique. Due to differential pressure maintained between the dust and plasma chambers, the dust grains move

  1. Search for the QCD ground state

    International Nuclear Information System (INIS)

    Reuter, M.; Wetterich, C.

    1994-05-01

    Within the Euclidean effective action approach we propose criteria for the ground state of QCD. Despite a nonvanishing field strength the ground state should be invariant with respect to modified Poincare transformations consisting of a combination of translations and rotations with suitable gauge transformations. We have found candidate states for QCD with four or more colours. The formation of gluon condensates shows similarities with the Higgs phenomenon. (orig.)

  2. Basic equations of quasiparticle-phonon model of nucleus with account of Pauli principle and phonons interactions in ground state

    International Nuclear Information System (INIS)

    Voronov, V.V.; Dang, N.D.

    1984-01-01

    the system of equations, enabling to calculate the energy and the structure of excited states, described by the wave function, containing one- and two-phon components was obtained in the framework of quasiparticlephonon model. The requirements of Pauli principle for two-phonon components and phonon correlation in the ground nucleus state are taken into account

  3. ATHENS SEASONAL VARIATION OF GROUND RESISTANCE PREDICTION USING NEURAL NETWORKS

    Directory of Open Access Journals (Sweden)

    S. Anbazhagan

    2015-10-01

    Full Text Available The objective in ground resistance is to attain the most minimal ground safety esteem conceivable that bodes well monetarily and physically. An application of artificial neural networks (ANN to presage and relegation has been growing rapidly due to sundry unique characteristics of ANN models. A decent forecast is able to capture the dubiousness associated with those ground resistance. A portion of the key instabilities are soil composition, moisture content, temperature, ground electrodes and spacing of the electrodes. Propelled by this need, this paper endeavors to develop a generalized regression neural network (GRNN to predict the ground resistance. The GRNN has a single design parameter and expeditious learning and efficacious modeling for nonlinear time series. The precision of the forecast is applied to the Athens seasonal variation of ground resistance that shows the efficacy of the proposed approach.

  4. Impurity magnetopolaron in a parabolic quantum dot: the squeezed-state variational approach

    International Nuclear Information System (INIS)

    Kandemir, B S; Cetin, A

    2005-01-01

    We present a calculation of the ground-state binding energy of an impurity magnetopolaron confined in a three-dimensional (3D) parabolic quantum dot potential, in the framework of a variational approach based on two successive canonical transformations. First, we apply a displaced-oscillator type unitary transformation to diagonalize the relevant Froehlich Hamiltonian. Second, a single-mode squeezed-state transformation is introduced to deal with bilinear terms arising from the first transformation. Finally, the parameters of these transformations together with the parameters included in the electronic trial wavefunction are determined variationally to obtain the ground-state binding energy of an impurity magnetopolaron confined in a 3D parabolic quantum dot potential. Our approach has two advantages: first, the displaced-oscillator transformation allows one to obtain results valid for whole range of electron-phonon coupling strength since it is a special combination of Lee-Low-Pines and Huybrechts (LLP-H) canonical transformations, and second, the later transformation improves all-coupling results. It has been shown that the effects of quadratic terms arising from the all-coupling approach are very important and should be taken into account in studying the size-dependent physical properties of nanostructured materials

  5. Compact binary coalescences in the band of ground-based gravitational-wave detectors

    International Nuclear Information System (INIS)

    Mandel, Ilya; O'Shaughnessy, Richard

    2010-01-01

    As the ground-based gravitational-wave telescopes LIGO, Virgo and GEO 600 approach the era of first detections, we review the current knowledge of the coalescence rates and the mass and spin distributions of merging neutron-star and black-hole binaries. We emphasize the bi-directional connection between gravitational-wave astronomy and conventional astrophysics. Astrophysical input will make possible informed decisions about optimal detector configurations and search techniques. Meanwhile, rate upper limits, detected merger rates and the distribution of masses and spins measured by gravitational-wave searches will constrain astrophysical parameters through comparisons with astrophysical models. Future developments necessary to the success of gravitational-wave astronomy are discussed.

  6. Is the ground state of Yang-Mills theory Coulombic?

    Science.gov (United States)

    Heinzl, T.; Ilderton, A.; Langfeld, K.; Lavelle, M.; Lutz, W.; McMullan, D.

    2008-08-01

    We study trial states modelling the heavy quark-antiquark ground state in SU(2) Yang-Mills theory. A state describing the flux tube between quarks as a thin string of glue is found to be a poor description of the continuum ground state; the infinitesimal thickness of the string leads to UV artifacts which suppress the overlap with the ground state. Contrastingly, a state which surrounds the quarks with non-Abelian Coulomb fields is found to have a good overlap with the ground state for all charge separations. In fact, the overlap increases as the lattice regulator is removed. This opens up the possibility that the Coulomb state is the true ground state in the continuum limit.

  7. Force-balance and differential equation for the ground-state electron density in atoms and molecules

    International Nuclear Information System (INIS)

    Amovilli, C.; March, N.H.; Gal, T.; Nagy, A.

    2000-01-01

    Holas and March (1995) established a force-balance equation from the many-electron Schroedinger equation. Here, the authors propose this as a basis for the construction of a (usually approximate) differential equation for the ground-state electron density. By way of example they present the simple case of two-electron systems with different external potentials but with weak electron-electron Coulomb repulsion λe 2 /r 12 . In this case first-order Rayleigh-Schroedinger (RS) perturbation theory of the ground-state wave function is known to lead to a compact expression for the first-order density matrix γ(r,rprime) in terms of its diagonal density ρ(r) and the density corresponding to λ = 0. This result allows the force-balance equation to be written as a third-order linear, differential homogeneous equation for the ground-state electron density ρ(r). The example of the two-electron Hookean atom is treated: For this case one can also transcend the first-order RS perturbation theory and get exact results for discrete choices of force constants (external potential)

  8. Variational Transition State Theory

    Energy Technology Data Exchange (ETDEWEB)

    Truhlar, Donald G. [Univ. of Minnesota, Minneapolis, MN (United States)

    2016-09-29

    This is the final report on a project involving the development and applications of variational transition state theory. This project involved the development of variational transition state theory for gas-phase reactions, including optimized multidimensional tunneling contributions and the application of this theory to gas-phase reactions with a special emphasis on developing reaction rate theory in directions that are important for applications to combustion. The development of variational transition state theory with optimized multidimensional tunneling as a useful computational tool for combustion kinetics involved eight objectives.

  9. Propagation properties of Rossby waves for latitudinal β-plane variations of f and zonal variations of the shallow water speed

    Directory of Open Access Journals (Sweden)

    C. T. Duba

    2012-05-01

    Full Text Available Using the shallow water equations for a rotating layer of fluid, the wave and dispersion equations for Rossby waves are developed for the cases of both the standard β-plane approximation for the latitudinal variation of the Coriolis parameter f and a zonal variation of the shallow water speed. It is well known that the wave normal diagram for the standard (mid-latitude Rossby wave on a β-plane is a circle in wave number (ky,kx space, whose centre is displaced −β/2 ω units along the negative kx axis, and whose radius is less than this displacement, which means that phase propagation is entirely westward. This form of anisotropy (arising from the latitudinal y variation of f, combined with the highly dispersive nature of the wave, gives rise to a group velocity diagram which permits eastward as well as westward propagation. It is shown that the group velocity diagram is an ellipse, whose centre is displaced westward, and whose major and minor axes give the maximum westward, eastward and northward (southward group speeds as functions of the frequency and a parameter m which measures the ratio of the low frequency-long wavelength Rossby wave speed to the shallow water speed. We believe these properties of group velocity diagram have not been elucidated in this way before. We present a similar derivation of the wave normal diagram and its associated group velocity curve for the case of a zonal (x variation of the shallow water speed, which may arise when the depth of an ocean varies zonally from a continental shelf.

  10. Mesoscale variations in acoustic signals induced by atmospheric gravity waves.

    Science.gov (United States)

    Chunchuzov, Igor; Kulichkov, Sergey; Perepelkin, Vitaly; Ziemann, Astrid; Arnold, Klaus; Kniffka, Anke

    2009-02-01

    The results of acoustic tomographic monitoring of the coherent structures in the lower atmosphere and the effects of these structures on acoustic signal parameters are analyzed in the present study. From the measurements of acoustic travel time fluctuations (periods 1 min-1 h) with distant receivers, the temporal fluctuations of the effective sound speed and wind speed are retrieved along different ray paths connecting an acoustic pulse source and several receivers. By using a coherence analysis of the fluctuations near spatially distanced ray turning points, the internal wave-associated fluctuations are filtered and their spatial characteristics (coherences, horizontal phase velocities, and spatial scales) are estimated. The capability of acoustic tomography in estimating wind shear near ground is shown. A possible mechanism describing the temporal modulation of the near-ground wind field by ducted internal waves in the troposphere is proposed.

  11. State-to-state quantum dynamics of the F + HCl (vi = 0, ji = 0) → HF(vf, jf) + Cl reaction on the ground state potential energy surface.

    Science.gov (United States)

    Li, Anyang; Guo, Hua; Sun, Zhigang; Kłos, Jacek; Alexander, Millard H

    2013-10-07

    The state-to-state reaction dynamics of the title reaction is investigated on the ground electronic state potential energy surface using two quantum dynamical methods. The results obtained using the Chebyshev real wave packet method are in excellent agreement with those obtained using the time-independent method, except at low translational energies. It is shown that this exothermic hydrogen abstraction reaction is direct, resulting in a strong back-scattered bias in the product angular distribution. The HF product is highly excited internally. Agreement with available experimental data is only qualitative. We discuss several possible causes of disagreement with experiment.

  12. Is the ground state of Yang-Mills theory Coulombic?

    OpenAIRE

    Heinzl, Thomas; Ilderton, Anton; Langfeld, Kurt; Lavelle, Martin; Lutz, Wolfgang; McMullan, David

    2008-01-01

    We study trial states modelling the heavy quark-antiquark ground state in SU(2) Yang-Mills theory. A state describing the flux tube between quarks as a thin string of glue is found to be a poor description of the continuum ground state; the infinitesimal thickness of the string leads to UV artifacts which suppress the overlap with the ground state. Contrastingly, a state which surrounds the quarks with non-abelian Coulomb fields is found to have a good overlap with the ground state for all ch...

  13. The codes WAV3BDY and WAV4BDY and the variational Monte Carlo method

    International Nuclear Information System (INIS)

    Schiavilla, R.

    1987-01-01

    A description of the codes WAV3BDY and WAV4BDY, which generate the variational ground state wave functions of the A=3 and 4 nuclei, is given, followed by a discussion of the Monte Carlo integration technique, which is used to calculate expectation values and transition amplitudes of operators, and for whose implementation WAV3BDY and WAV4BDY are well suited

  14. Effect of the ground state correlations in the density distribution and zero point fluctuations

    International Nuclear Information System (INIS)

    Barranco, F.; Broglia, R.A.

    1985-01-01

    The existence of collective vibrations in the spectrum implies that the description of the ground state in an independent particle model must be corrected. This is because of the zero point fluctuations induced by the collective vibrations, so that ground state correlations have to be included. These are taken into account via the diagrammatic expansion of the Nuclear Field Theory, giving place to a renormalization in the different properties of the ground state. As far as the density distribution is concerned, in a NFT consistent calculation, the largest contributions arise from diagrams that cannot be expressed in terms of backward going amplitudes of the phonon RPA wave function. For a given multipolarity the main correction comes from the low lying state. The giant resonance is of smaller relevance since it lies at larger energies in the response function. The octupole modes give the dominant contribution, and the effect in average becomes smaller as the multipolarity increases. These results agree quite well with those obtained taking into account the zero point fluctuations of the nuclear surface in the collective model with the Esbensen and Bertsch prescription, which the authors use to explain the anomalous behaviour of the mean square radii of the Calcium isotopes

  15. Fermionic molecular dynamics for ground states and collisions of nuclei

    International Nuclear Information System (INIS)

    Feldmeier, H.; Bieler, K.; Schnack, J.

    1994-08-01

    The antisymmetric many-body trial state which describes a system of interacting fermions is parametrized in terms of localized wave packets. The equations of motion are derived from the time-dependent quantum variational principle. The resulting Fermionic Molecular Dynamics (FMD) equations include a wide range of semi-quantal to classical physics extending from deformed Hartree-Fock theory to Newtonian molecular dynamics. Conservation laws are discussed in connection with the choice of the trial state. The model is applied to heavy-ion collisions with which its basic features are illustrated. The results show a great variety of phenomena including deeply inelastic collisions, fusion, incomplete fusion, fragmentation, neck emission, promptly emitted nucleons and evaporation. (orig.)

  16. Evaluation of dynamic properties of soft ground using an S-wave vibrator and seismic cones. Part 2. Vs change during the vibration; S ha vibrator oyobi seismic cone wo mochiita gen`ichi jiban no doteki bussei hyoka. 2. Kashinchu no Vs no henka

    Energy Technology Data Exchange (ETDEWEB)

    Inazaki, T [Public Works Research Institute, Tsukuba (Japan)

    1997-05-27

    With an objective to measure a behavior of the surface ground during a strong earthquake directly on the actual ground and make evaluation thereon, a proposal was made on an original location measuring and analyzing method using an S-wave vibrator and seismic cones. This system consists of an S-wave vibrator and a static cone penetrating machine, and different types of measuring cones. A large number of measuring cones are inserted initially in the object bed of the ground, and variation in the vibration generated by the vibrator is measured. This method can derive decrease in rigidity rate of the actual ground according to dynamic strain levels, or in other words, the dynamic nonlinearity. The strain levels can be controlled with a range from 10 {sup -5} to 10 {sup -3} by varying the distance from the S-wave vibrator. Furthermore, the decrease in the rigidity rate can be derived by measuring variations in the S-wave velocity by using the plank hammering method during the vibration. Field measurement is as easy as it can be completed in about half a day including preparatory works, and the data analysis is also simple. The method is superior in mobility and workability. 9 figs.

  17. Implementation of rigorous renormalization group method for ground space and low-energy states of local Hamiltonians

    Science.gov (United States)

    Roberts, Brenden; Vidick, Thomas; Motrunich, Olexei I.

    2017-12-01

    The success of polynomial-time tensor network methods for computing ground states of certain quantum local Hamiltonians has recently been given a sound theoretical basis by Arad et al. [Math. Phys. 356, 65 (2017), 10.1007/s00220-017-2973-z]. The convergence proof, however, relies on "rigorous renormalization group" (RRG) techniques which differ fundamentally from existing algorithms. We introduce a practical adaptation of the RRG procedure which, while no longer theoretically guaranteed to converge, finds matrix product state ansatz approximations to the ground spaces and low-lying excited spectra of local Hamiltonians in realistic situations. In contrast to other schemes, RRG does not utilize variational methods on tensor networks. Rather, it operates on subsets of the system Hilbert space by constructing approximations to the global ground space in a treelike manner. We evaluate the algorithm numerically, finding similar performance to density matrix renormalization group (DMRG) in the case of a gapped nondegenerate Hamiltonian. Even in challenging situations of criticality, large ground-state degeneracy, or long-range entanglement, RRG remains able to identify candidate states having large overlap with ground and low-energy eigenstates, outperforming DMRG in some cases.

  18. Variations mechanism in entropy of wave height field and its relation with thermodynamic entropy

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This paper gives a brief description of annual period and seasonal variation in the wave height field entropy in the northeastern Pacific. A calculation of the quantity of the, received by lithosphere systems in the northern hemisphere is introduced. The wave heat field entropy is compared with the difference in the quantity of the sun's radiation heat. Analysis on the transfer method, period and lag of this seasonal variation led to the conclusion that the annual period and seasonal variation in the entropy of the wave height field in the Northwestern Pacific is due to the seasonal variation of the sun's radiation heat. Furthermore, the inconsistency between thermodynamic entropy and information entropy was studied.

  19. α-decay half-lives of some nuclei from ground state to ground state using different nuclear potential

    Directory of Open Access Journals (Sweden)

    Akrawy Dashty T.

    2018-01-01

    Full Text Available Theoretical α-decay half-lives of some nuclei from ground state to ground state are calculated using different nuclear potential model including Coulomb proximity potential (CPPM, Royer proximity potential and Broglia and Winther 1991. The calculated values comparing with experimental data, it is observed that the CPPM model is in good agreement with the experimental data.

  20. Nuclear ground state

    International Nuclear Information System (INIS)

    Negele, J.W.

    1975-01-01

    The nuclear ground state is surveyed theoretically, and specific suggestions are given on how to critically test the theory experimentally. Detailed results on 208 Pb are discussed, isolating several features of the charge density distributions. Analyses of 208 Pb electron scattering and muonic data are also considered. 14 figures

  1. Variations in nearshore waves along Karnataka, west coast of India

    Indian Academy of Sciences (India)

    Honnavar and Karwar) along the 200 km stretch of the state of Karnataka in 2009 during 27 ... Seas; swells; wind waves; Arabian Sea; mixed sea state; wave spectrum. ..... Range and average value of the wave parameters at three locations during three different ..... fully developed seas based on the similarity theory of S A.

  2. Sensitivity of Gravity Wave Fluxes to Interannual Variations in Tropical Convection and Zonal Wind.

    Science.gov (United States)

    Alexander, M Joan; Ortland, David A; Grimsdell, Alison W; Kim, Ji-Eun

    2017-09-01

    Using an idealized model framework with high-frequency tropical latent heating variability derived from global satellite observations of precipitation and clouds, the authors examine the properties and effects of gravity waves in the lower stratosphere, contrasting conditions in an El Niño year and a La Niña year. The model generates a broad spectrum of tropical waves including planetary-scale waves through mesoscale gravity waves. The authors compare modeled monthly mean regional variations in wind and temperature with reanalyses and validate the modeled gravity waves using satellite- and balloon-based estimates of gravity wave momentum flux. Some interesting changes in the gravity spectrum of momentum flux are found in the model, which are discussed in terms of the interannual variations in clouds, precipitation, and large-scale winds. While regional variations in clouds, precipitation, and winds are dramatic, the mean gravity wave zonal momentum fluxes entering the stratosphere differ by only 11%. The modeled intermittency in gravity wave momentum flux is shown to be very realistic compared to observations, and the largest-amplitude waves are related to significant gravity wave drag forces in the lowermost stratosphere. This strong intermittency is generally absent or weak in climate models because of deficiencies in parameterizations of gravity wave intermittency. These results suggest a way forward to improve model representations of the lowermost stratospheric quasi-biennial oscillation winds and teleconnections.

  3. Hartree–Fock variational bounds for ground state energy of ...

    Indian Academy of Sciences (India)

    volume V0, with mass m, electric charge zero, and magnetic moment μ, interacting through magnetic dipole–dipole ... like neutrinos, with finite magnetic dipole moment has not drawn too much at- tention. In an earlier .... to its value in the equatorial kx − ky plane for the same value of the magnitude of the wave vector. Note ...

  4. Back radiation suppression through a semi-transparent round ground plane for a mm-Wave monopole antenna

    KAUST Repository

    Klionovski, Kirill; Farooqui, Muhammad Fahad; Shamim, Atif

    2017-01-01

    Omnidirectional radiation pattern with minimum backward radiation is highly desirable for millimeter-wave telecommunication antennas. In this work, we propose a round, semitransparent ground plane of radius 0.8λ with uniform impedance distribution that can reduce the back radiation of a monopole antenna by 8.8 dB as compared with a similar sized metallic ground plane. The value of uniform impedance is obtained through analytical optimization by using asymptotic expressions in the Kirchhoff approximation of the radiation pattern of a toroidal wave scattered by a round semitransparent ground plane. The semitransparent ground plane has been realized using a low-cost carbon paste on a Kapton film. Experimental results match closely with those of simulations and validate the overall concept.

  5. Back radiation suppression through a semi-transparent round ground plane for a mm-Wave monopole antenna

    KAUST Repository

    Klionovski, Kirill

    2017-10-25

    Omnidirectional radiation pattern with minimum backward radiation is highly desirable for millimeter-wave telecommunication antennas. In this work, we propose a round, semitransparent ground plane of radius 0.8λ with uniform impedance distribution that can reduce the back radiation of a monopole antenna by 8.8 dB as compared with a similar sized metallic ground plane. The value of uniform impedance is obtained through analytical optimization by using asymptotic expressions in the Kirchhoff approximation of the radiation pattern of a toroidal wave scattered by a round semitransparent ground plane. The semitransparent ground plane has been realized using a low-cost carbon paste on a Kapton film. Experimental results match closely with those of simulations and validate the overall concept.

  6. Variation with age of anisotropy under oceans, from great circle surface waves

    International Nuclear Information System (INIS)

    Journet, B.; Jobert, N.

    1982-01-01

    Global great circle measurements of regionalized mantle Love wave phase velocities are interpreted in terms of regional models. The same study had been made by J. J. Leveque (1980) for Rayleigh waves, and the resulting models for the two oceanic regions of different ages are used as a basis for comparison: the observed Love wave dispersion cannot be explained with these models if isotropic. The models obtained by inversion of Love wave data are compared with the models mentioned; the discrepancy appearing in the 250 km depth range between the velocities β/sub H/ and β/sub V/ of respectively SH and SV waves is indicative of polarization anisotropy. Moreover, we put forward a significant variation from young to old oceans: the difference between β/sub H/, and β/sub V/ is of the order of 1% for the former, compared to 3% for the latter. This variation can bring information about the behaviour of upper mantle materials in connection with the motion of oceanic plates

  7. Variations of helicon wave induced radial plasma transport in different experimental conditions

    International Nuclear Information System (INIS)

    Petrzilka, V.

    1993-08-01

    Variations of the helicon wave induced radial plasma transport are presented in dependence on values of the plasma radius, magnetostatic field, plasma density, frequency of the helicon wave and on the ion charge. 22 refs., 14 figs

  8. Near-Field Ground Motion Modal versus Wave Propagation Analysis

    Directory of Open Access Journals (Sweden)

    Artur Cichowicz

    2010-01-01

    Full Text Available The response spectrum generally provides a good estimate of the global displacement and acceleration demand of far-field ground motion on a structure. However, it does not provide accurate information on the local shape or internal deformation of the response of the structure. Near-field pulse-like ground motion will propagate through the structure as waves, causing large, localized deformation. Therefore, the response spectrum alone is not a sufficient representation of near-field ground motion features. Results show that the drift-response technique based on a continuous shear-beam model has to be employed here to estimate structure-demand parameters when structure is exposed to the pulse like ground motion. Conduced modeling shows limited applicability of the drift spectrum based on the SDOF approximation. The SDOF drift spectrum approximation can only be applied to structures with smaller natural periods than the dominant period of the ground motion. For periods larger than the dominant period of ground motion the SDOF drift spectra model significantly underestimates maximum deformation. Strong pulse-type motions are observed in the near-source region of large earthquakes; however, there is a lack of waveforms collected from small earthquakes at very close distances that were recorded underground in mines. The results presented in this paper are relevant for structures with a height of a few meters, placed in an underground excavation. The strong ground motion sensors recorded mine-induced earthquakes in a deep gold mine, South Africa. The strongest monitored horizontal ground motion was caused by an event of magnitude 2 at a distance of 90 m with PGA 123 m/s2, causing drifts of 0.25%–0.35%. The weak underground motion has spectral characteristics similar to the strong ground motion observed on the earth's surface; the drift spectrum has a maximum value less than 0.02%.

  9. Temporal variation of uranium in ground water with conductivity

    International Nuclear Information System (INIS)

    Pulhani, Vandana; Chaudhury, Moushumi D.; Jha, S.K.; Tripathi, R.M.

    2015-01-01

    The concentration of uranium in drinking water sources is a matter of health concern since it has been proved to be chemo-toxic to humans. Uranium being a more soluble actinide is also very mobile in the environment. The effect of water quality parameters and their co-relation to uranium content in the water is an interesting study to understand and predict its behavior in ground water and subsequently to judge the hazard posed. Hence studies on spatial and temporal variation of uranium concentration with electrical conductivity, pH, total dissolved solids and salinity in ground water was carried out. (author)

  10. Quantum Monte Carlo and the equation of state of liquid 3He

    International Nuclear Information System (INIS)

    Panoff, R.M.

    1987-01-01

    The author briefly reviews the present status of Monte Carlo technology as it applies to the study of the ground-state properties of strongly-interacting many-fermion systems in general, and to liquid 3 He at zero temperature in particular. Variational Monte Carlo methods are reviewed and the model many-body problem to be tackled is introduced. He outlines the domain Green's function Monte Carlo method with mirror potentials providing a coherent framework for discussing solutions to the fermion problem. He presents results for the zero-temperature equation of state of 3 He, along with other ground-state properties derived from the many-body wave function

  11. A simple and realistic triton wave function

    International Nuclear Information System (INIS)

    Lomnitz-Adler, J.; Pandharipande, V.R.

    1980-01-01

    We propose a simple triton wave function that consists of a product of three correlation operators operating on a three-body spin-isospin state. This wave function is formally similar to that used in the recent variational theories of nuclear matter, the main difference being in the long-range behavior of the correlation operators. Variational calculations are carried out with the Reid potential, using this wave function in the so-called 'symmetrized product' and 'independent pair' forms. The triton energy and density distributions obtained with the symmetrized product wave function agree with those obtained in Faddeev and other variational calculations using harmonic oscillator states. The proposed wave function and calculational methods can be easily generalized to treat the four-nucleon α-particle. (orig.)

  12. Seasonal variation and sources of atmospheric gravity waves in the Antarctic

    Directory of Open Access Journals (Sweden)

    Kaoru Sato

    2010-12-01

    Full Text Available In the last recent ten years, our knowledge of gravity waves in the Antarctic has been significantly improved through numerous studies using balloon and satellite observations and high-resolution model simulations. In this report, we introduce results from two studies which were performed as a part of the NIPR project "Integrated analysis of the material circulation in the Antarctic atmosphere-cryosphere-ocean" (2004-2009, i.e., Yoshiki et al. (2004 and Sato and Yoshiki (2008. These two studies focused on the seasonal variation and sources of the gravity waves in the Antarctic, because horizontal wavelengths and phase velocities depend largely on the wave sources. The former study used original high-resolution data from operational radiosonde observations at Syowa Station. In the lowermost stratosphere, gravity waves do not exhibit characteristic seasonal variation; instead, the wave energy is intensified when lower latitude air intrudes into the area near Syowa Station in the upper troposphere. This intrusion is associated with blocking events or developed synoptic-scale waves. In the lower and middle stratosphere, the gravity wave energy is maximized in spring and particularly intensified when the axis of the polar night jet approaches Syowa Station. The latter study is based on intensive radiosonde observation campaigns that were performed in 2002 at Syowa Station as an activity of JARE-43. Gravity wave propagation was statistically examined using two dimensional (i.e., vertical wavenumber versus frequency spectra in each season. It was shown that the gravity waves are radiated upward and downward from an unbalanced region of the polar night jet. This feature is consistent with the gravity-wave resolving GCM simulation.

  13. Classical many-particle systems with unique disordered ground states

    Science.gov (United States)

    Zhang, G.; Stillinger, F. H.; Torquato, S.

    2017-10-01

    Classical ground states (global energy-minimizing configurations) of many-particle systems are typically unique crystalline structures, implying zero enumeration entropy of distinct patterns (aside from trivial symmetry operations). By contrast, the few previously known disordered classical ground states of many-particle systems are all high-entropy (highly degenerate) states. Here we show computationally that our recently proposed "perfect-glass" many-particle model [Sci. Rep. 6, 36963 (2016), 10.1038/srep36963] possesses disordered classical ground states with a zero entropy: a highly counterintuitive situation . For all of the system sizes, parameters, and space dimensions that we have numerically investigated, the disordered ground states are unique such that they can always be superposed onto each other or their mirror image. At low energies, the density of states obtained from simulations matches those calculated from the harmonic approximation near a single ground state, further confirming ground-state uniqueness. Our discovery provides singular examples in which entropy and disorder are at odds with one another. The zero-entropy ground states provide a unique perspective on the celebrated Kauzmann-entropy crisis in which the extrapolated entropy of a supercooled liquid drops below that of the crystal. We expect that our disordered unique patterns to be of value in fields beyond glass physics, including applications in cryptography as pseudorandom functions with tunable computational complexity.

  14. Study of Ground State Wave-function of the Neutron-rich 29,30Na Isotopes through Coulomb Breakup

    Directory of Open Access Journals (Sweden)

    Rahaman A.

    2014-03-01

    Full Text Available Coulomb breakup of unstable neutron rich nuclei 29,30Na around the ‘island of inversion’ has been studied at energy around 434 MeV/nucleon and 409 MeV/nucleon respectively. Four momentum vectors of fragments, decay neutron from excited projectile and γ-rays emitted from excited fragments after Coulomb breakup are measured in coincidence. For these nuclei, the low-lying dipole strength above one neutron threshold can be explained by direct breakup model. The analysis for Coulomb breakup of 29,30Na shows that large amount of the cross section yields the 28Na, 29Na core in ground state. The predominant ground-state configuration of 29,30Na is found to be 28Na(g.s⊗νs1/2 and 29Na(g.s⊗νs1/2,respectively.

  15. Seismic Response of Power Transmission Tower-Line System Subjected to Spatially Varying Ground Motions

    Directory of Open Access Journals (Sweden)

    Li Tian

    2010-01-01

    Full Text Available The behavior of power transmission tower-line system subjected to spatially varying base excitations is studied in this paper. The transmission towers are modeled by beam elements while the transmission lines are modeled by cable elements that account for the nonlinear geometry of the cables. The real multistation data from SMART-1 are used to analyze the system response subjected to spatially varying ground motions. The seismic input waves for vertical and horizontal ground motions are also generated based on the Code for Design of Seismic of Electrical Installations. Both the incoherency of seismic waves and wave travel effects are accounted for. The nonlinear time history analytical method is used in the analysis. The effects of boundary conditions, ground motion spatial variations, the incident angle of the seismic wave, coherency loss, and wave travel on the system are investigated. The results show that the uniform ground motion at all supports of system does not provide the most critical case for the response calculations.

  16. Bounded dust-acoustic waves in a cylindrically bounded collisional dusty plasma with dust charge variation

    International Nuclear Information System (INIS)

    Wei Nanxia; Xue Jukui

    2006-01-01

    Taking into account the boundary, particle collisions, and dust charging effects, dust-acoustic waves in a uniform cylindrically bounded dusty plasma is investigated analytically, and the dispersion relation for the dust-acoustic wave is obtained. The effects of boundary, dust charge variation, particle collision, and dust size on the dust-acoustic wave are discussed in detail. Due to the bounded cylindrical boundary effects, the radial wave number is discrete, i.e., the spectrum is discrete. It is shown that the discrete spectrum, the adiabatic dust charge variation, dust grain size, and the particle collision have significant effects on the dust-acoustic wave

  17. Cavity optomechanics -- beyond the ground state

    Science.gov (United States)

    Meystre, Pierre

    2011-05-01

    The coupling of coherent optical systems to micromechanical devices, combined with breakthroughs in nanofabrication and in ultracold science, has opened up the exciting new field of cavity optomechanics. Cooling of the vibrational motion of a broad range on oscillating cantilevers and mirrors near their ground state has been demonstrated, and the ground state of at least one such system has now been reached. Cavity optomechanics offers much promise in addressing fundamental physics questions and in applications such as the detection of feeble forces and fields, or the coherent control of AMO systems and of nanoscale electromechanical devices. However, these applications require taking cavity optomechanics ``beyond the ground state.'' This includes the generation and detection of squeezed and other non-classical states, the transfer of squeezing between electromagnetic fields and motional quadratures, and the development of measurement schemes for the characterization of nanomechanical structures. The talk will present recent ``beyond ground state'' developments in cavity optomechanics. We will show how the magnetic coupling between a mechanical membrane and a BEC - or between a mechanical tuning fork and a nanoscale cantilever - permits to control and monitor the center-of-mass position of the mechanical system, and will comment on the measurement back-action on the membrane motion. We will also discuss of state transfer between optical and microwave fields and micromechanical devices. Work done in collaboration with Dan Goldbaum, Greg Phelps, Keith Schwab, Swati Singh, Steve Steinke, Mehmet Tesgin, and Mukund Vengallatore and supported by ARO, DARPA, NSF, and ONR.

  18. Influence of ground state correlations on the properties of the first 2+ and 3- states in some Sm isotopes

    International Nuclear Information System (INIS)

    Navrotskaya-Rybarska, V.; Stoyanova, O.; Stoyanov, Ch.

    1980-01-01

    The influence of ground state correlations and of their coupling with the phonon amplitudes on the properties of the first collective states is investigated in some Sm isotopes. Equations for the eXcited state energies are derived using the variational principle. Formulae for the gap and quasiparticle energies are given. The numerical calculations are performed for sup(144-150)Sm. The energies of the 2 + - and 3 - - states and the B(E2) and B(E3) electric transition probability values are presented. The effects studied are shown to be small for sup(144-146)Sm but the collectivity of the 2sub(1)sup(+) and 3sub(1)sup(-) states decreases strongly for 150 Sm [ru

  19. Ground-state energy of an exciton-(LO) phonon system in a parabolic quantum well

    Science.gov (United States)

    Gerlach, B.; Wüsthoff, J.; Smondyrev, M. A.

    1999-12-01

    This paper presents a variational study of the ground-state energy of an exciton-(LO) phonon system, which is spatially confined to a quantum well. The exciton-phonon interaction is of Fröhlich type, the confinement potentials are assumed to be parabolic functions of the coordinates. Making use of functional integral techniques, the phonon part of the problem can be eliminated exactly, leading us to an effective two-particle system, which has the same spectral properties as the original one. Subsequently, Jensen's inequality is applied to obtain an upper bound on the ground-state energy. The main intention of this paper is to analyze the influence of the quantum-well-induced localization of the exciton on its ground-state energy (or its binding energy, respectively). To do so, we neglect any mismatch of the masses or the dielectric constants, but admit an arbitrary strength of the confinement potentials. Our approach allows for a smooth interpolation of the ultimate limits of vanishing and infinite confinement, corresponding to the cases of a free three-dimensional and a free two-dimensional exciton-phonon system. The interpolation formula for the ground-state energy bound corresponds to similar formulas for the free polaron or the free exciton-phonon system. These bounds in turn are known to compare favorably with all previous ones, which we are aware of.

  20. Liquid 4He: Modified LOCV ground-state energy calculations

    International Nuclear Information System (INIS)

    Skjetne, B.; Ostgaard, E.

    1996-01-01

    The ground-state energetics of liquid 4 He is studied in a constrained variational approach, where the significance of neglecting terms beyond second order in the cluster expansion is estimated in a crude way. An adjustment to the conditions of healing on the two-body correlation function excludes from the global average field the effects of pairwise clustering to higher orders. To this end, open-quotes virtualclose quotes particles beyond nearest neighbors are included in the average correlation volume. Results within the scope of such modifications are consistent with GFMC and QDMC calculations, falling within the range -7.25 ± 0.05 K when recent interaction models are used

  1. Stability properties of solitary waves for fractional KdV and BBM equations

    Science.gov (United States)

    Angulo Pava, Jaime

    2018-03-01

    This paper sheds new light on the stability properties of solitary wave solutions associated with Korteweg-de Vries-type models when the dispersion is very low. Using a compact, analytic approach and asymptotic perturbation theory, we establish sufficient conditions for the existence of exponentially growing solutions to the linearized problem and so a criterium of spectral instability of solitary waves is obtained for both models. Moreover, the nonlinear stability and spectral instability of the ground state solutions for both models is obtained for some specific regimen of parameters. Via a Lyapunov strategy and a variational analysis, we obtain the stability of the blow-up of solitary waves for the critical fractional KdV equation. The arguments presented in this investigation show promise for use in the study of the instability of traveling wave solutions of other nonlinear evolution equations.

  2. Ground waves caused by gas cloud explosions and their effects on nuclear power plant structures

    International Nuclear Information System (INIS)

    Werkle, H.; Waas, G.

    1983-01-01

    The response of embedded structures to ground waves caused by the explosion of a gas cloud is studied. In the first step, the free field ground motion is analyzed; then the response of a PWR-building is computed. The analysis of the free-field motion is performed using a two-dimensional plane strain model, whereas the interaction problem of the structure excited by the free-field motion is investigated using an axisymmetric three-dimensional model. The soil is assumed to be viscoelastic and horizontally layered. The equations of motion for the viscoelastic continuum are solved in the frequency domain by a semianalytic method. The travelling surface loads from air pressure waves are represented by superposition of line loads. The superposition takes advantage of the mathematical properties of the Fourier transforms. Explicit ring load solutions are used to solve the three-dimensional interaction problem of a rigid embedded circular foundation excited by a two-dimensional wave field of Rayleigh wave type. (orig./WL)

  3. Dust acoustic shock wave generation due to dust charge variation in ...

    Indian Academy of Sciences (India)

    to generation of shock wave in the dusty plasma described as collisionless shock wave. ... Trans- forming to the frame of the wave with velocity λ ζ = x λd -λωpdt =X -λT. (2) .... Jd =0, there exists steady state (apart from the initial state) defined.

  4. Discrete-State Simulated Annealing For Traveling-Wave Tube Slow-Wave Circuit Optimization

    Science.gov (United States)

    Wilson, Jeffrey D.; Bulson, Brian A.; Kory, Carol L.; Williams, W. Dan (Technical Monitor)

    2001-01-01

    Algorithms based on the global optimization technique of simulated annealing (SA) have proven useful in designing traveling-wave tube (TWT) slow-wave circuits for high RF power efficiency. The characteristic of SA that enables it to determine a globally optimized solution is its ability to accept non-improving moves in a controlled manner. In the initial stages of the optimization, the algorithm moves freely through configuration space, accepting most of the proposed designs. This freedom of movement allows non-intuitive designs to be explored rather than restricting the optimization to local improvement upon the initial configuration. As the optimization proceeds, the rate of acceptance of non-improving moves is gradually reduced until the algorithm converges to the optimized solution. The rate at which the freedom of movement is decreased is known as the annealing or cooling schedule of the SA algorithm. The main disadvantage of SA is that there is not a rigorous theoretical foundation for determining the parameters of the cooling schedule. The choice of these parameters is highly problem dependent and the designer needs to experiment in order to determine values that will provide a good optimization in a reasonable amount of computational time. This experimentation can absorb a large amount of time especially when the algorithm is being applied to a new type of design. In order to eliminate this disadvantage, a variation of SA known as discrete-state simulated annealing (DSSA), was recently developed. DSSA provides the theoretical foundation for a generic cooling schedule which is problem independent, Results of similar quality to SA can be obtained, but without the extra computational time required to tune the cooling parameters. Two algorithm variations based on DSSA were developed and programmed into a Microsoft Excel spreadsheet graphical user interface (GUI) to the two-dimensional nonlinear multisignal helix traveling-wave amplifier analysis program TWA3

  5. High-altitude electromagnetic pulse environment over the lossy ground

    International Nuclear Information System (INIS)

    Xie Yanzhao; Wang Zanji

    2003-01-01

    The electromagnetic field above ground produced by an incident high-altitude electromagnetic pulse plane wave striking the ground plane was described in this paper in terms of the Fresnel reflection coefficients and the numerical FFT. The pulse reflected from the ground plane always cancel the incident field for the horizontal field component, but the reflected field adds to the incident for the vertical field component. The results of several cases for variations in the observation height, angle of incidence and lossy ground electrical parameters were also presented showing different e-field components above the earth

  6. Bayesian hierarchical model for variations in earthquake peak ground acceleration within small-aperture arrays

    KAUST Repository

    Rahpeyma, Sahar

    2018-04-17

    Knowledge of the characteristics of earthquake ground motion is fundamental for earthquake hazard assessments. Over small distances, relative to the source–site distance, where uniform site conditions are expected, the ground motion variability is also expected to be insignificant. However, despite being located on what has been characterized as a uniform lava‐rock site condition, considerable peak ground acceleration (PGA) variations were observed on stations of a small‐aperture array (covering approximately 1 km2) of accelerographs in Southwest Iceland during the Ölfus earthquake of magnitude 6.3 on May 29, 2008 and its sequence of aftershocks. We propose a novel Bayesian hierarchical model for the PGA variations accounting separately for earthquake event effects, station effects, and event‐station effects. An efficient posterior inference scheme based on Markov chain Monte Carlo (MCMC) simulations is proposed for the new model. The variance of the station effect is certainly different from zero according to the posterior density, indicating that individual station effects are different from one another. The Bayesian hierarchical model thus captures the observed PGA variations and quantifies to what extent the source and recording sites contribute to the overall variation in ground motions over relatively small distances on the lava‐rock site condition.

  7. Bayesian hierarchical model for variations in earthquake peak ground acceleration within small-aperture arrays

    KAUST Repository

    Rahpeyma, Sahar; Halldorsson, Benedikt; Hrafnkelsson, Birgir; Jonsson, Sigurjon

    2018-01-01

    Knowledge of the characteristics of earthquake ground motion is fundamental for earthquake hazard assessments. Over small distances, relative to the source–site distance, where uniform site conditions are expected, the ground motion variability is also expected to be insignificant. However, despite being located on what has been characterized as a uniform lava‐rock site condition, considerable peak ground acceleration (PGA) variations were observed on stations of a small‐aperture array (covering approximately 1 km2) of accelerographs in Southwest Iceland during the Ölfus earthquake of magnitude 6.3 on May 29, 2008 and its sequence of aftershocks. We propose a novel Bayesian hierarchical model for the PGA variations accounting separately for earthquake event effects, station effects, and event‐station effects. An efficient posterior inference scheme based on Markov chain Monte Carlo (MCMC) simulations is proposed for the new model. The variance of the station effect is certainly different from zero according to the posterior density, indicating that individual station effects are different from one another. The Bayesian hierarchical model thus captures the observed PGA variations and quantifies to what extent the source and recording sites contribute to the overall variation in ground motions over relatively small distances on the lava‐rock site condition.

  8. Ground-state inversion method applied to calculation of molecular photoionization cross-sections by atomic extrapolation: Interference effects at low energies

    International Nuclear Information System (INIS)

    Hilton, P.R.; Nordholm, S.; Hush, N.S.

    1980-01-01

    The ground-state inversion method, which we have previously developed for the calculation of atomic cross-sections, is applied to the calculation of molecular photoionization cross-sections. These are obtained as a weighted sum of atomic subshell cross-sections plus multi-centre interference terms. The atomic cross-sections are calculated directly for the atomic functions which when summed over centre and symmetry yield the molecular orbital wave function. The use of the ground-state inversion method for this allows the effect of the molecular environment on the atomic cross-sections to be calculated. Multi-centre terms are estimated on the basis of an effective plane-wave expression for this contribution to the total cross-section. Finally the method is applied to the range of photon energies from 0 to 44 eV where atomic extrapolation procedures have not previously been tested. Results obtained for H 2 , N 2 and CO show good agreement with experiment, particularly when interference effects and effects of the molecular environment on the atomic cross-sections are included. The accuracy is very much better than that of previous plane-wave and orthogonalized plane-wave methods, and can stand comparison with that of recent more sophisticated approaches. It is a feature of the method that calculation of cross-sections either of atoms or of large molecules requires very little computer time, provided that good quality wave functions are available, and it is then of considerable potential practical interest for photoelectorn spectroscopy. (orig.)

  9. Ground state searches in fcc intermetallics

    International Nuclear Information System (INIS)

    Wolverton, C.; de Fontaine, D.; Ceder, G.; Dreysse, H.

    1991-12-01

    A cluster expansion is used to predict the fcc ground states, i.e., the stable phases at zero Kelvin as a function of composition, for alloy systems. The intermetallic structures are not assumed, but derived regorously by minimizing the configurational energy subject to linear constraints. This ground state search includes pair and multiplet interactions which spatially extend to fourth nearest neighbor. A large number of these concentration-independent interactions are computed by the method of direct configurational averaging using a linearized-muffin-tin orbital Hamiltonian cast into tight binding form (TB-LMTO). The interactions, derived without the use of any adjustable or experimentally obtained parameters, are compared to those calculated via the generalized perturbation method extention of the coherent potential approximation within the context of a KKR Hamiltonian (KKR-CPA-GPM). Agreement with the KKR-CPA-GPM results is quite excellent, as is the comparison of the ground state results with the fcc-based portions of the experimentally-determined phase diagrams under consideration

  10. Ground eigenvalue and eigenfunction of a spin-weighted spheroidal wave equation in low frequencies

    Institute of Scientific and Technical Information of China (English)

    Tang Wen-Lin; Tian Gui-Hua

    2011-01-01

    Spin-weighted spheroidal wave functions play an important role in the study of the linear stability of rotating Kerr black holes and are studied by the perturbation method in supersymmetric quantum mechanics. Their analytic ground eigenvalues and eigenfunctions are obtained by means of a series in low frequency. The ground eigenvalue and eigenfunction for small complex frequencies are numerically determined.

  11. Construction of A Trial Function In The Variational Procedure of ...

    African Journals Online (AJOL)

    A form of variational method for calculating the ground state energy of a quantum mechanical system is considered. The method is based on a systematic construction of a trial variational function at each step of the calculation of the ground state energy. The construction involves introducing more variational parameters to ...

  12. BCS wave function, matrix product states, and the Ising conformal field theory

    Science.gov (United States)

    Montes, Sebastián; Rodríguez-Laguna, Javier; Sierra, Germán

    2017-11-01

    We present a characterization of the many-body lattice wave functions obtained from the conformal blocks (CBs) of the Ising conformal field theory (CFT). The formalism is interpreted as a matrix product state using continuous ancillary degrees of freedom. We provide analytic and numerical evidence that the resulting states can be written as BCS states. We give a complete proof that the translationally invariant 1D configurations have a BCS form and we find suitable parent Hamiltonians. In particular, we prove that the ground state of the finite-size critical Ising transverse field (ITF) Hamiltonian can be obtained with this construction. Finally, we study 2D configurations using an operator product expansion (OPE) approximation. We associate these states to the weak pairing phase of the p +i p superconductor via the scaling of the pairing function and the entanglement spectrum.

  13. Induced Electromagnetic Field by Seismic Waves in Stratified Media in Earth's Magnetic Field

    Science.gov (United States)

    Yamazaki, K.

    2017-12-01

    Seismic waves accompany electromagnetic (EM) variations because Earth's crust involves a variety of EM properties such as finite electrical conductivity and ion contents. If we can catch the EM variations just after the earthquake rupture, we will know the occurrence of earthquake before the arrival of seismic waves at observation point. However, quantitative aspects of EM variations arising from seismic waves have not sufficiently understood. Together with observational works, theoretical works have been made to simulate EM variations arising from seismic waves. The generation mechanisms of EM variations include electrokinetic effect (Pride, 1994), motional induction (Gao et al., 2014), piezo-electric effect (Ogawa and Utada, 2000), piezo-magnetic effect (Yamazaki, 2016), etc. It is widely accepted that the electrokinetic effect is the dominant mechanism. Theoretical calculation of EM variations assuming the electrokinetic effect roughly explains the observed EM variations accompanying with earthquake ground motions (e.g. Gao et al. 2016). However, there are a significant disagreement between observed and predicted EM variations. In the present study, I focus on the motional induction mechanism that possibly explain some parts of EM variations accompanying with seismic waves. A theoretical work on EM variations arising from the motional induction has been presented by Gao et al. (2014), but their work assumed uniform full-space medium. In contrast, the present work assumes stratified media which correctly incorporate the effect of the ground surface. I apply a calculating method developed in seismology (e.g. Kennett, 2013) and in EM studies (Haartsen and Pride, 1997), and derive a set of expressions describing the spatial-temporal variations of the EM field after the onset of rupture. The derived formula is used to calculate EM variations for actual earthquakes to compare the theoretical prediction to observed EM variations.

  14. Exploration of deep S-wave velocity structure using microtremor array technique to estimate long-period ground motion

    International Nuclear Information System (INIS)

    Sato, Hiroaki; Higashi, Sadanori; Sato, Kiyotaka

    2007-01-01

    In this study, microtremor array measurements were conducted at 9 sites in the Niigata plain to explore deep S-wave velocity structures for estimation of long-period earthquake ground motion. The 1D S-wave velocity profiles in the Niigata plain are characterized by 5 layers with S-wave velocities of 0.4, 0.8, 1.5, 2.1 and 3.0 km/s, respectively. The depth to the basement layer is deeper in the Niigata port area located at the Japan sea side of the Niigata plain. In this area, the basement depth is about 4.8 km around the Seirou town and about 4.1 km around the Niigata city, respectively. These features about the basement depth in the Niigata plain are consistent with the previous surveys. In order to verify the profiles derived from microtremor array exploration, we estimate the group velocities of Love wave for four propagation paths of long-period earthquake ground motion during Niigata-ken tyuetsu earthquake by multiple filter technique, which were compared with the theoretical ones calculated from the derived profiles. As a result, it was confirmed that the group velocities from the derived profiles were in good agreement with the ones from long-period earthquake ground motion records during Niigata-ken tyuetsu earthquake. Furthermore, we applied the estimation method of design basis earthquake input for seismically isolated nuclear power facilities by using normal mode solution to estimate long-period earthquake ground motion during Niigata-ken tyuetsu earthquake. As a result, it was demonstrated that the applicability of the above method for the estimation of long-period earthquake ground motion were improved by using the derived 1D S-wave velocity profile. (author)

  15. D-Wave Electron-H, -He+, and -Li2+ Elastic Scattering and Photoabsorption in P States of Two-Electron Systems

    Science.gov (United States)

    Bhatia, A. K.

    2014-01-01

    In previous papers [A. K. Bhatia, Phys. Rev. A 85, 052708 (2012); 86, 032709 (2012); 87, 042705 (2013)] electron-H, -He+, and -Li2+ P-wave scattering phase shifts were calculated using the variational polarized orbital theory. This method is now extended to the singlet and triplet D-wave scattering in the elastic region. The long-range correlations are included in the Schrodinger equation by using the method of polarized orbitals variationally. Phase shifts are compared to those obtained by other methods. The present calculation provides results which are rigorous lower bonds to the exact phase shifts. Using the presently calculated D-wave and previously calculated S-wave continuum functions, photoionization of singlet and triplet P states of He and Li+ are also calculated, along with the radiative recombination rate coefficients at various electron temperatures.

  16. Ground Motion Prediction for Great Interplate Earthquakes in Kanto Basin Considering Variation of Source Parameters

    Science.gov (United States)

    Sekiguchi, H.; Yoshimi, M.; Horikawa, H.

    2011-12-01

    Broadband ground motions are estimated in the Kanto sedimentary basin which holds Tokyo metropolitan area inside for anticipated great interplate earthquakes along surrounding plate boundaries. Possible scenarios of great earthquakes along Sagami trough are modeled combining characteristic properties of the source area and adequate variation in source parameters in order to evaluate possible ground motion variation due to next Kanto earthquake. South to the rupture area of the 2011 Tohoku earthquake along the Japan trench, we consider possible M8 earthquake. The ground motions are computed with a four-step hybrid technique. We first calculate low-frequency ground motions at the engineering basement. We then calculate higher-frequency ground motions at the same position, and combine the lower- and higher-frequency motions using a matched filter. We finally calculate ground motions at the surface by computing the response of the alluvium-diluvium layers to the combined motions at the engineering basement.

  17. The variational 2D Boussinesq model for wave propagation over a shoal

    NARCIS (Netherlands)

    Adytia, D.; van Groesen, Embrecht W.C.

    2011-01-01

    The Variational Boussinesq Model (VBM) for waves (Klopman et al. 2010) is based on the Hamiltonian structure of gravity surface waves. In its approximation, the fluid potential in the kinetic energy is approximated by the sum of its value at the free surface and a linear combination of vertical

  18. The resonating group method three cluster approach to the ground state 9 Li nucleus structure

    International Nuclear Information System (INIS)

    Filippov, G.F.; Pozdnyakov, Yu.A.; Terenetsky, K.O.; Verbitsky, V.P.

    1994-01-01

    The three-cluster approach for light atomic nuclei is formulated in frame of the algebraic version of resonating group method. Overlap integral and Hamiltonian matrix elements on generating functions are obtained for 9 Li nucleus. All permissible by Pauli principle 9 Li different cluster nucleon permutations were taken into account in the calculations. The results obtained can be easily generalised on any three-cluster system up to 12 C. Matrix elements obtained in the work were used in the variational calculations of the ground state energetic and geometric 9 Li characteristics. It is shown that 9 Li ground state is not adequate to the shell model limit and has pronounced three-cluster structure. (author). 16 refs., 4 tab., 2 figs

  19. Coulomb Final State Interactions for Gaussian Wave Packets

    CERN Document Server

    Wiedemann, Urs Achim; Heinz, Ulrich W

    1999-01-01

    Two-particle like-sign and unlike-sign correlations including Coulomb final state interactions are calculated for Gaussian wave packets emitted from a Gaussian source. We show that the width of the wave packets can be fully absorbed into the spatial and momentum space widths of an effective emission function for plane wave states, and that Coulomb final state interaction effects are sensitive only to the latter, but not to the wave packet width itself. Results from analytical and numerical calculations are compared with recently published work by other authors.

  20. Singlet Ground State Magnetism:

    DEFF Research Database (Denmark)

    Loidl, A.; Knorr, K.; Kjems, Jørgen

    1979-01-01

    The magneticGamma 1 –Gamma 4 exciton of the singlet ground state system TbP has been studied by inelastic neutron scattering above the antiferromagnetic ordering temperature. Considerable dispersion and a pronounced splitting was found in the [100] and [110] directions. Both the band width...

  1. Optimization of nonlinear wave function parameters

    International Nuclear Information System (INIS)

    Shepard, R.; Minkoff, M.; Chemistry

    2006-01-01

    An energy-based optimization method is presented for our recently developed nonlinear wave function expansion form for electronic wave functions. This expansion form is based on spin eigenfunctions, using the graphical unitary group approach (GUGA). The wave function is expanded in a basis of product functions, allowing application to closed-shell and open-shell systems and to ground and excited electronic states. Each product basis function is itself a multiconfigurational function that depends on a relatively small number of nonlinear parameters called arc factors. The energy-based optimization is formulated in terms of analytic arc factor gradients and orbital-level Hamiltonian matrices that correspond to a specific kind of uncontraction of each of the product basis functions. These orbital-level Hamiltonian matrices give an intuitive representation of the energy in terms of disjoint subsets of the arc factors, they provide for an efficient computation of gradients of the energy with respect to the arc factors, and they allow optimal arc factors to be determined in closed form for subspaces of the full variation problem. Timings for energy and arc factor gradient computations involving expansion spaces of > 10 24 configuration state functions are reported. Preliminary convergence studies and molecular dissociation curves are presented for some small molecules

  2. A variational Integro-Differential Equation for three identical particles in an S-state

    International Nuclear Information System (INIS)

    Fabre de la Ripelle, M.; Braun, M.; Sofianos, S.A.

    1997-01-01

    Starting from the Schroedinger equation, a new Variational Integro-Differential Equation (VIDE) for three bosons in S-state is derived. The wave function has the simple structure of a sum of two-body amplitudes. It is shown that the new equation gives results which are three orders of magnitude better than the corresponding results obtained from a single Faddeev equation, where the pairs are in an S-state. The latter equation generates an exact solution only for S-state projected potentials. Moreover, the ghost contributions occurring in the Faddeev amplitudes for three bosons in an S-state do not exist in the new equation. (author)

  3. Variational approach for transition between quasi 2D and 3D behaviour of the binding energy of screened excitons in highly confined quantum wells

    Science.gov (United States)

    Vazquez, Gerardo J.; del Castillo-Mussot, Marcelo; Reyes, J. Adrian; Lee, J.; Spector, Harold N.

    2001-03-01

    Variational calculations are presented of the ground exciton state in quantum wells in the Thomas-Fremi approximation (TFA) as a function of the screening parameter and the width of the quantum well, going from quasi-2D to 3D sysytems. Our calculations were performed using three different variational wave functions. The screening parameter in the TFA depends on both temperature and carrier densities. We study the values of the screening parameter for which there exists bound excitons.

  4. The launching and propagation of drift waves in a steady-state plasma

    International Nuclear Information System (INIS)

    Sandeman, J.; Elliott, J.A.; Sutcliffe, M.; Rusbridge, M.G.

    1992-01-01

    The UMIST linear quadrupole GOLUX is a steady-state device in which hydrogen plasma is continuously injected axially, at one end, from an external duoplasmatron source. The electron temperature in the drift wave region is about 1 eV, and the density about 10 15 m -3 . Self-excited intrinsic drift modes are observed in the shared flux region of GOLUX, forming a broad band between 30 and 50 kHz. Drift waves may also be launched into the system, by passing an AC current through the plasma between the two flag antennae. These coherent launched waves present a powerful means of studying drift wave phenomena. We obtain information about the launched wave by detecting both density and potential fluctuations, using a small cylindrical Langmuir probe and lock-in amplifier techniques. Scanning the probe in the longitudinal (z) direction yields the spatial variation of amplitude and phase with respect to the launching signal; the ratio of the wave potential, extrapolated back to the probe, to the launching current gives the launching impedance, a measure of the effectiveness of the launching process. (author) 5 refs., 6 figs

  5. Degenerate Ground State in a Mesoscopic YBa2Cu3O

    International Nuclear Information System (INIS)

    Il'ichev, E.; Grajcar, M.; Hlubina, R.; IJsselsteijn, R. P. J.; Hoenig, H. E.; Meyer, H.-G.; Golubov, A.; Amin, M. H. S.; Zagoskin, A. M.; Omelyanchouk, A. N.

    2001-01-01

    We have measured the current-phase relationship I (var-phi) of symmetric 45 degree YBa 2 Cu 3 O 7-x grain boundary Josephson junctions. Substantial deviations of the Josephson current from conventional tunnel-junction behavior have been observed: (i) The critical current exhibits, as a function of temperature T , a local minimum at a temperature T * . (ii) At T∼T * , the first harmonic of I(var-phi) changes sign. (iii) For T * , the second harmonic of I(var-phi) is comparable to the first harmonic, and (iv) the ground state of the junction becomes degenerate. The results are in good agreement with a microscopic model of Josephson junctions between d -wave superconductors

  6. Hydromagnetic Waves in the Magnetosphere and the Ionosphere

    CERN Document Server

    Alperovich, Leonid S

    2007-01-01

    The book deals with Ultra-Low-Frequency (ULF)-electromagnetic waves observed on Earth and in Space. These are so-called geomagnetic variations or pulsations. Alfvén's discovery related to the influence of the strong magnetic field on the conducting fluids (magnetohydrodynamics) led to development of the concept that the ULF-waves are magnetospheric magnetohydrodynamic (MHD)-waves. MHD-waves at their propagation gather information about the magnetosphere, ionosphere, and the ground. There are two applied aspects based on using the ULF electromagnetic oscillations. The first one is the ground-based diagnostics of the magnetosphere. This is an attempt to monitor in the real time the magnetosphere size, distance to the last closed field-lines, distribution of the cold plasma, etc. The second one is the deep electromagnetic sounding of the Earth. The basis for these studies is the capability of any electromagnetic wave to penetrate a conductor to a finite depth. The ULF-waves can reach the depth of a few hundred ...

  7. 66Ga ground state β spectrum

    DEFF Research Database (Denmark)

    Severin, Gregory; Knutson, L. D.; Voytas, P. A.

    2014-01-01

    The ground state branch of the β decay of 66Ga is an allowed Fermi (0+ → 0+) transition with a relatively high f t value. The large f t and the isospin-forbidden nature of the transition indicates that the shape of the β spectrum of this branch may be sensitive to higher order contributions...... to the decay. Two previous measurements of the shape have revealed deviations from an allowed spectrum but disagree about whether the shape factor has a positive or negative slope. As a test of a new iron-free superconducting β spectrometer, we have measured the shape of the ground state branch of the 66Ga β...... spectrum above a positron energy of 1.9 MeV. The spectrum is consistent with an allowed shape, with the slope of the shape factor being zero to within ±3 × 10−3 per MeV. We have also determined the endpoint energy for the ground state branch to be 4.1535 ± 0.0003 (stat.) ±0.0007 (syst.) MeV, in good...

  8. Performance testing of lead free primers: blast waves, velocity variations, and environmental testing

    OpenAIRE

    Courtney, Elya; Courtney, Amy; Summer, Peter David; Courtney, Michael

    2014-01-01

    Results are presented for lead free primers based on diazodinitrophenol (DDNP)compared with tests on lead styphnate based primers. First, barrel friction measurements in 5.56 mm NATO are presented. Second, shot to shot variations in blast waves are presented as determined by detonating primers in a 7.62x51mm rifle chamber with a firing pin, but without any powder or bullet loaded and measuring the blast wave at the muzzle with a high speed pressure transducer. Third, variations in primer blas...

  9. Hylleraas-Configuration Interaction study of the 1S ground state of the negative Li ion.

    Science.gov (United States)

    Sims, James S

    2017-12-28

    In a previous work Sims and Hagstrom [J. Chem. Phys. 140, 224312 (2014)] reported Hylleraas-Configuration Interaction (Hy-CI) method variational calculations for the neutral atom and positive ion 1 S ground states of the beryllium isoelectronic sequence. The Li - ion, nominally the first member of this series, has a decidedly different electronic structure. This paper reports the results of a large, comparable calculation for the Li - ground state to explore how well the Hy-CI method can represent the more diffuse L shell of Li - which is representative of the Be(2sns) excited states as well. The best non-relativistic energy obtained was -7.500 776 596 hartree, indicating that 10 - 20 nh accuracy is attainable in Hy-CI and that convergence of the r 12 r 34 double cusp is fast and that this correlation type can be accurately represented within the Hy-CI model.

  10. Macroscopic Quantum States and Quantum Phase Transition in the Dicke Model

    International Nuclear Information System (INIS)

    Lian Jin-Ling; Zhang Yuan-Wei; Liang Jiu-Qing

    2012-01-01

    The energy spectrum of Dicke Hamiltonians with and without the rotating wave approximation for an arbitrary atom number is obtained analytically by means of the variational method, in which the effective pseudo-spin Hamiltonian resulting from the expectation value in the boson-field coherent state is diagonalized by the spin-coherent-state transformation. In addition to the ground-state energy, an excited macroscopic quantum-state is found corresponding to the south- and north-pole gauges of the spin-coherent states, respectively. Our results of ground-state energies in exact agreement with various approaches show that these models exhibit a zero-temperature quantum phase transition of the second order for any number of atoms, which was commonly considered as a phenomenon of the thermodynamic limit with the atom number tending to infinity. The critical behavior of the geometric phase is analyzed. (general)

  11. Ground receiving station (GRS) of UMS - receiving and processing the electromagnetic wave data from satellite

    International Nuclear Information System (INIS)

    Mohammad Syahmi Nordin; Fauziah Abdul Aziz

    2007-01-01

    The low resolution Automatic Picture Transmission (APT) data from the National Oceanic and Atmospheric Administration (NOAA) polar-orbiting satellites Advanced Very High Resolution Radiometer (AVHRR) is being received and recorded in real-time mode at ground receiving station in School of Science and Technology, Universiti Malaysia Sabah. The system is suitable for the developing and undeveloped countries in south and Southeast Asia and is said to be acceptable for engineering, agricultural, climatological and environmental applications. The system comprises a personal computer attached with a small APT receiver. The data transmission between the ground receiving station and NOAA satellites is using the electromagnetic wave. The relation for receiving and processing the electromagnetic wave in the transmission will be discussed. (Author)

  12. Exact ground-state correlation functions of one-dimenisonal strongly correlated electron models with resonating-valence-bond ground state

    International Nuclear Information System (INIS)

    Yamanaka, Masanori; Honjo, Shinsuke; Kohmoto, Mahito

    1996-01-01

    We investigate one-dimensional strongly correlated electron models which have the resonating-valence-bond state as the exact ground state. The correlation functions are evaluated exactly using the transfer matrix method for the geometric representations of the valence-bond states. In this method, we only treat matrices with small dimensions. This enables us to give analytical results. It is shown that the correlation functions decay exponentially with distance. The result suggests that there is a finite excitation gap, and that the ground state is insulating. Since the corresponding noninteracting systems may be insulating or metallic, we can say that the gap originates from strong correlation. The persistent currents of the present models are also investigated and found to be exactly vanishing

  13. Accurate adiabatic energy surfaces for the ground and first excited states of He2+

    International Nuclear Information System (INIS)

    Lee, E.P.F.

    1993-01-01

    Different factors affecting the accuracy of the computed energy surfaces of the ground and first excited state of He 2 + have been examined, including the choice of the one-and many-particle bases, the configurational space in the MRCI (multi-reference configuration interaction) calculations and other corrections such as the Davidson and the full counterpoise (CP) correction. From basis-variation studies, it was concluded that multi-reference direct-CI calculations (MRDCI) using CASSCF MOs and/or natural orbitals (NOs) from a smaller CISD calculation, gave results close to full CI. The computed dissociation energies, D e , for the ground and first excited state of He 2 + were 2.4670 (2.4659) eV and 17.2 (17.1) cm -1 , respectively, at the highest level [without and with CP correction for basis-set superposition errors (BSSE)] of calculation with an [11s8p3d1f] GTO contraction, in reasonably good agreement with previous calculations, and estimated correct values, where available. It is believed that the computed D e , and the energy surface for the first excited state should be reasonably accurate. However, for the ground state, the effects of multiple f functions and/or functions of higher angular momentum have not been investigated owing to limitation of the available computing resources. This is probably the only weakness is the present study. (Author)

  14. Variational study of the stability of the Nagaoka state against single-spin flips in the two-dimensional t-t#prime# Hubbard model

    International Nuclear Information System (INIS)

    Bajdich, M.; Hlubina, R.

    2001-01-01

    Making use of variational wave functions of the Basile-Elser type we study the stability of the Nagaoka state against single-spin flips in the two-dimensional t-t#prime# Hubbard model for t#prime#/t∼0.5. In the low-density limit the variational estimate of the stability region of the Nagaoka state is in qualitative agreement with the predictions of the T-matrix approximation

  15. Coupling a Surface Acoustic Wave to an Electron Spin in Diamond via a Dark State

    Directory of Open Access Journals (Sweden)

    D. Andrew Golter

    2016-12-01

    Full Text Available The emerging field of quantum acoustics explores interactions between acoustic waves and artificial atoms and their applications in quantum information processing. In this experimental study, we demonstrate the coupling between a surface acoustic wave (SAW and an electron spin in diamond by taking advantage of the strong strain coupling of the excited states of a nitrogen vacancy center while avoiding the short lifetime of these states. The SAW-spin coupling takes place through a Λ-type three-level system where two ground spin states couple to a common excited state through a phonon-assisted as well as a direct dipole optical transition. Both coherent population trapping and optically driven spin transitions have been realized. The coherent population trapping demonstrates the coupling between a SAW and an electron spin coherence through a dark state. The optically driven spin transitions, which resemble the sideband transitions in a trapped-ion system, can enable the quantum control of both spin and mechanical degrees of freedom and potentially a trapped-ion-like solid-state system for applications in quantum computing. These results establish an experimental platform for spin-based quantum acoustics, bridging the gap between spintronics and quantum acoustics.

  16. Model track studies on fouled ballast using ground penetrating radar and multichannel analysis of surface wave

    Science.gov (United States)

    Anbazhagan, P.; Lijun, Su; Buddhima, Indraratna; Cholachat, Rujikiatkamjorn

    2011-08-01

    Ballast fouling is created by the breakdown of aggregates or outside contamination by coal dust from coal trains, or from soil intrusion beneath rail track. Due to ballast fouling, the conditions of rail track can be deteriorated considerably depending on the type of fouling material and the degree of fouling. So far there is no comprehensive guideline available to identify the critical degree of fouling for different types of fouling materials. This paper presents the identification of degree of fouling and types of fouling using non-destructive testing, namely seismic surface-wave and ground penetrating radar (GPR) survey. To understand this, a model rail track with different degree of fouling has been constructed in Civil engineering laboratory, University of Wollongong, Australia. Shear wave velocity obtained from seismic survey has been employed to identify the degree of fouling and types of fouling material. It is found that shear wave velocity of fouled ballast increases initially, reaches optimum fouling point (OFP), and decreases when the fouling increases. The degree of fouling corresponding after which the shear wave velocity of fouled ballast will be smaller than that of clean ballast is called the critical fouling point (CFP). Ground penetrating radar with four different ground coupled antennas (500 MHz, 800 MHz, 1.6 GHz and 2.3 GHz) was also used to identify the ballast fouling condition. It is found that the 800 MHz ground coupled antenna gives a better signal in assessing the ballast fouling condition. Seismic survey is relatively slow when compared to GPR survey however it gives quantifiable results. In contrast, GPR survey is faster and better in estimating the depth of fouling.

  17. Quantum chemical study of the nature of the ground state and the pressure-induced spin transition in CaFeO3

    NARCIS (Netherlands)

    Sadoc, Aymeric; de Graaf, Coen; Broer, Ria

    Ab initio calculations have been performed to clarify the character of the electronic ground state of the high-temperature phase of CaFeO3 at different external pressures. The analysis of the correlated N-electron wave function of properly embedded FeO6 clusters in terms of optimal atomic orbitals

  18. Status and plans for future generations of ground-based interferometric gravitational wave antennas

    International Nuclear Information System (INIS)

    Kawamura, Seiji

    2003-01-01

    Several medium- to large-scale ground-based interferometric gravitational-wave antennas have been constructed around the world. Although these antennas of the first generation could detect gravitational waves within a few years, it is necessary to improve the sensitivity of the detectors significantly with advanced technologies to ensure more frequent detection of gravitational waves. Stronger seismic isolation and reduction of thermal noise, especially using cryogenic mirrors, are among the most important technologies that can lead us to the realization of advanced detectors. Some of the advanced technologies are already implemented in some of the existing detectors and others are currently being investigated for the future-generation detectors such as advanced LIGO, LCGT, upgrade of GEO600, AIGO, and EURO. We expect that such advanced detectors will eventually open a new window to the universe and establish a new field, 'gravitational wave astronomy'

  19. Acoustic waves in the atmosphere and ground generated by volcanic activity

    International Nuclear Information System (INIS)

    Ichihara, Mie; Lyons, John; Oikawa, Jun; Takeo, Minoru

    2012-01-01

    This paper reports an interesting sequence of harmonic tremor observed in the 2011 eruption of Shinmoe-dake volcano, southern Japan. The main eruptive activity started with ashcloud forming explosive eruptions, followed by lava effusion. Harmonic tremor was transmitted into the ground and observed as seismic waves at the last stage of the effusive eruption. The tremor observed at this stage had unclear and fluctuating harmonic modes. In the atmosphere, on the other hand, many impulsive acoustic waves indicating small surface explosions were observed. When the effusion stopped and the erupted lava began explosive degassing, harmonic tremor started to be transmitted also to the atmosphere and observed as acoustic waves. Then the harmonic modes became clearer and more stable. This sequence of harmonic tremor is interpreted as a process in which volcanic degassing generates an open connection between the volcanic conduit and the atmosphere. In order to test this hypothesis, a laboratory experiment was performed and the essential features were successfully reproduced.

  20. Acoustic waves in the atmosphere and ground generated by volcanic activity

    Energy Technology Data Exchange (ETDEWEB)

    Ichihara, Mie; Lyons, John; Oikawa, Jun; Takeo, Minoru [Earthquake Research Institute, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032 (Japan); Instituto Geofisico, Escuela Politecnica Nacional, Ladron de Guevara E11-253, Aptdo 2759, Quito (Ecuador); Earthquake Research Institute, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032 (Japan)

    2012-09-04

    This paper reports an interesting sequence of harmonic tremor observed in the 2011 eruption of Shinmoe-dake volcano, southern Japan. The main eruptive activity started with ashcloud forming explosive eruptions, followed by lava effusion. Harmonic tremor was transmitted into the ground and observed as seismic waves at the last stage of the effusive eruption. The tremor observed at this stage had unclear and fluctuating harmonic modes. In the atmosphere, on the other hand, many impulsive acoustic waves indicating small surface explosions were observed. When the effusion stopped and the erupted lava began explosive degassing, harmonic tremor started to be transmitted also to the atmosphere and observed as acoustic waves. Then the harmonic modes became clearer and more stable. This sequence of harmonic tremor is interpreted as a process in which volcanic degassing generates an open connection between the volcanic conduit and the atmosphere. In order to test this hypothesis, a laboratory experiment was performed and the essential features were successfully reproduced.

  1. Observing Tsunamis in the Ionosphere Using Ground Based GPS Measurements

    Science.gov (United States)

    Galvan, D. A.; Komjathy, A.; Song, Y. Tony; Stephens, P.; Hickey, M. P.; Foster, J.

    2011-01-01

    Ground-based Global Positioning System (GPS) measurements of ionospheric Total Electron Content (TEC) show variations consistent with atmospheric internal gravity waves caused by ocean tsunamis following recent seismic events, including the Tohoku tsunami of March 11, 2011. We observe fluctuations correlated in time, space, and wave properties with this tsunami in TEC estimates processed using JPL's Global Ionospheric Mapping Software. These TEC estimates were band-pass filtered to remove ionospheric TEC variations with periods outside the typical range of internal gravity waves caused by tsunamis. Observable variations in TEC appear correlated with the Tohoku tsunami near the epicenter, at Hawaii, and near the west coast of North America. Disturbance magnitudes are 1-10% of the background TEC value. Observations near the epicenter are compared to estimates of expected tsunami-driven TEC variations produced by Embry Riddle Aeronautical University's Spectral Full Wave Model, an atmosphere-ionosphere coupling model, and found to be in good agreement. The potential exists to apply these detection techniques to real-time GPS TEC data, providing estimates of tsunami speed and amplitude that may be useful for future early warning systems.

  2. Remote pipeline assessment and condition monitoring using low-frequency axisymmetric waves: a theoretical study of torsional wave motion

    Science.gov (United States)

    Muggleton, J. M.; Rustighi, E.; Gao, Y.

    2016-09-01

    Waves that propagate at low frequencies in buried pipes are of considerable interest in a variety of practical scenarios, for example leak detection, remote pipe detection, and pipeline condition assessment and monitoring. Particularly useful are the n = 0, or axisymmetric, modes in which there is no displacement (or pressure) variation over the pipe cross section. Previous work has focused on two of the three axisymmetric wavetypes that can propagate: the s = 1, fluid- dominated wave; and the s = 2, shell-dominated wave. In this paper, the third axisymmetric wavetype, the s = 0 torsional wave, is studied. Whilst there is a large body of research devoted to the study of torsional waves and their use for defect detection in pipes at ultrasonic frequencies, little is known about their behaviour and possible exploitation at lower frequencies. Here, a low- frequency analytical dispersion relationship is derived for the torsional wavenumber for a buried pipe from which both the wavespeed and wave attenuation can be obtained. How the torsional waves subsequently radiate to the ground surface is then investigated, with analytical expressions being presented for the ground surface displacement above the pipe resulting from torsional wave motion within the pipe wall. Example results are presented and, finally, how such waves might be exploited in practice is discussed.

  3. High-speed ground transportation development outside United States

    Energy Technology Data Exchange (ETDEWEB)

    Eastham, T.R. [Queen`s Univ., Kingston, Ontario (United Kingdom)

    1995-09-01

    This paper surveys the state of high-speed (in excess of 200 km/h) ground-transportation developments outside the United States. Both high-speed rail and Maglev systems are covered. Many vehicle systems capable of providing intercity service in the speed range 200--500 km/h are or will soon be available. The current state of various technologies, their implementation, and the near-term plans of countries that are most active in high-speed ground transportation development are reported.

  4. OBSERVATIONAL SELECTION EFFECTS WITH GROUND-BASED GRAVITATIONAL WAVE DETECTORS

    International Nuclear Information System (INIS)

    Chen, Hsin-Yu; Holz, Daniel E.; Essick, Reed; Vitale, Salvatore; Katsavounidis, Erik

    2017-01-01

    Ground-based interferometers are not perfect all-sky instruments, and it is important to account for their behavior when considering the distribution of detected events. In particular, the LIGO detectors are most sensitive to sources above North America and the Indian Ocean, and as the Earth rotates, the sensitive regions are swept across the sky. However, because the detectors do not acquire data uniformly over time, there is a net bias on detectable sources’ right ascensions. Both LIGO detectors preferentially collect data during their local night; it is more than twice as likely to be local midnight than noon when both detectors are operating. We discuss these selection effects and how they impact LIGO’s observations and electromagnetic (EM) follow-up. Beyond galactic foregrounds associated with seasonal variations, we find that equatorial observatories can access over 80% of the localization probability, while mid-latitudes will access closer to 70%. Facilities located near the two LIGO sites can observe sources closer to their zenith than their analogs in the south, but the average observation will still be no closer than 44° from zenith. We also find that observatories in Africa or the South Atlantic will wait systematically longer before they can begin observing compared to the rest of the world; though, there is a preference for longitudes near the LIGOs. These effects, along with knowledge of the LIGO antenna pattern, can inform EM follow-up activities and optimization, including the possibility of directing observations even before gravitational-wave events occur.

  5. OBSERVATIONAL SELECTION EFFECTS WITH GROUND-BASED GRAVITATIONAL WAVE DETECTORS

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hsin-Yu; Holz, Daniel E. [University of Chicago, Chicago, Illinois 60637 (United States); Essick, Reed; Vitale, Salvatore; Katsavounidis, Erik [LIGO, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2017-01-20

    Ground-based interferometers are not perfect all-sky instruments, and it is important to account for their behavior when considering the distribution of detected events. In particular, the LIGO detectors are most sensitive to sources above North America and the Indian Ocean, and as the Earth rotates, the sensitive regions are swept across the sky. However, because the detectors do not acquire data uniformly over time, there is a net bias on detectable sources’ right ascensions. Both LIGO detectors preferentially collect data during their local night; it is more than twice as likely to be local midnight than noon when both detectors are operating. We discuss these selection effects and how they impact LIGO’s observations and electromagnetic (EM) follow-up. Beyond galactic foregrounds associated with seasonal variations, we find that equatorial observatories can access over 80% of the localization probability, while mid-latitudes will access closer to 70%. Facilities located near the two LIGO sites can observe sources closer to their zenith than their analogs in the south, but the average observation will still be no closer than 44° from zenith. We also find that observatories in Africa or the South Atlantic will wait systematically longer before they can begin observing compared to the rest of the world; though, there is a preference for longitudes near the LIGOs. These effects, along with knowledge of the LIGO antenna pattern, can inform EM follow-up activities and optimization, including the possibility of directing observations even before gravitational-wave events occur.

  6. Total and single differential cross sections for the electron impact ionization of the ground state of helium

    International Nuclear Information System (INIS)

    Singh, T.S.C.; Choudhury, K.B.; Singh, M.B.; Deb, N.C.; Mukherjee, S.C.; Mazumdar, P.S.

    1997-01-01

    Total cross sections (TCS) and single differential cross sections (SDCS) have been computed for the single ionization of the ground state of helium by electron impact in a distorted wave formalism which takes into account the effects of the initial and final channel distortions. The present TCS and SDCS results are in fair agreement with the measured values and other theoretical predictions for the incident electron energy E i > 150 eV. (orig.)

  7. Variations of wave energy power in shoaling zone of Benin coastal zone

    Directory of Open Access Journals (Sweden)

    Mathias A. Houekpoheha

    2015-02-01

    Full Text Available Today, we observe at the population level, that the improvement in comfort is accompanied by an increase in the electrical energy required. The predicted exhaustion of fossil energy resources maintains some speculation. Their unequal geographical distribution justifies the energy dependence of Benin overlooked from outside. So it is urgent to explore the various sources of renewable energy available to Benin. In this work, using measurements made ​​by the Millennium Challenge Account (MCA-Benin as part of the extension of the port of Cotonou, with Boussinesq equations (Peregrine and Stokes waves dispersion relation, we characterized the variations of various swell parameters (height, wavelength, velocities in the shoaling zone on the study site and proceeded to estimate variations in wave energy power from deep waters to the bathymetric breaking point. Finally, the zone with high energy power (where the conversion of this energy into electrical energy would be profitable of these waves is highlighted on the site, the local water depth at the point of breaking waves is evaluated and results obtained allowed to justify the very energetic character take by these swells on this coast when they are close to the beach.

  8. Ulf waves in the auroral zone ionosphere and associated electron precipitation variations

    International Nuclear Information System (INIS)

    Petelski, E.F.; Fahleson, U.; Shawhan, S.D.

    1977-12-01

    On four rocket flights, ULF electric fields were observed in the nighttime auroral oval and in the polar cleft. They had periods between 0.5 and 3 sec, amplitudes from 2 to 30 mV/m, and exhibited left- and right-hand elliptical polarization. Intensifications of these fields often coincided with bursts of energetic electron precipitation which were on occasion modulated with nearly the same period as the fields. The events in the auroral oval were associated with substorms and visual auroral activity. The spectral and polarization properties of the ULF fields suggest that they represented the electric components of Pcl or Pil micropulsations. To model these waves and the concurrent electron flux variations, different mechanisms for wave excitation, electron acceleration, and wave-particle interaction are considered. One likely interpretation attributes the micropulsations to Birkeland current chopping by an unstable double layer located at approximately equal to 1 R(sub)E altitude. It is suggested that the double layer also accelerates the observed electrons, the electron flux variations being due either to the intrinsic variations of the double layer or to its interaction with the micropulsations. Due to the sparcity of parameters measured so far, the models are provisional. A follow-up experiment is proposed to further investigate the problem. (author)

  9. Hamiltonians and variational principles for Alfvén simple waves

    International Nuclear Information System (INIS)

    Webb, G M; Hu, Q; Roux, J A le; Dasgupta, B; Zank, G P

    2012-01-01

    The evolution equations for the magnetic field induction B with the wave phase for Alfvén simple waves are expressed as variational principles and in the Hamiltonian form. The evolution of B with the phase (which is a function of the space and time variables) depends on the generalized Frenet–Serret equations, in which the wave normal n (which is a function of the phase) is taken to be tangent to a curve X, in a 3D Cartesian geometry vector space. The physical variables (the gas density, fluid velocity, gas pressure and magnetic field induction) in the wave depend only on the phase. Three approaches are developed. One approach exploits the fact that the Frenet equations may be written as a 3D Hamiltonian system, which can be described using the Nambu bracket. It is shown that B as a function of the phase satisfies a modified version of the Frenet equations, and hence the magnetic field evolution equations can be expressed in the Hamiltonian form. A second approach develops an Euler–Poincaré variational formulation. A third approach uses the Frenet frame formulation, in which the hodograph of B moves on a sphere of constant radius and uses a stereographic projection transformation due to Darboux. The equations for the projected field components reduce to a complex Riccati equation. By using a Cole–Hopf transformation, the Riccati equation reduces to a linear second order differential equation for the new variable. A Hamiltonian formulation of the second order differential equation then allows the system to be written in the Hamiltonian form. Alignment dynamics equations for Alfvén simple waves give rise to a complex Riccati equation or, equivalently, to a quaternionic Riccati equation, which can be mapped onto the Riccati equation obtained by stereographic projection. (paper)

  10. Approximating the ground state of gapped quantum spin systems

    Energy Technology Data Exchange (ETDEWEB)

    Michalakis, Spyridon [Los Alamos National Laboratory; Hamza, Eman [NON LANL; Nachtergaele, Bruno [NON LANL; Sims, Robert [NON LANL

    2009-01-01

    We consider quantum spin systems defined on finite sets V equipped with a metric. In typical examples, V is a large, but finite subset of Z{sup d}. For finite range Hamiltonians with uniformly bounded interaction terms and a unique, gapped ground state, we demonstrate a locality property of the corresponding ground state projector. In such systems, this ground state projector can be approximated by the product of observables with quantifiable supports. In fact, given any subset {chi} {contained_in} V the ground state projector can be approximated by the product of two projections, one supported on {chi} and one supported on {chi}{sup c}, and a bounded observable supported on a boundary region in such a way that as the boundary region increases, the approximation becomes better. Such an approximation was useful in proving an area law in one dimension, and this result corresponds to a multi-dimensional analogue.

  11. Anomalous width variation of rarefactive ion acoustic solitary waves in the context of auroral plasmas

    Directory of Open Access Journals (Sweden)

    S. S. Ghosh

    2004-01-01

    Full Text Available The presence of dynamic, large amplitude solitary waves in the auroral regions of space is well known. Since their velocities are of the order of the ion acoustic speed, they may well be considered as being generated from the nonlinear evolution of ion acoustic waves. However, they do not show the expected width-amplitude correlation for K-dV solitons. Recent POLAR observations have actually revealed that the low altitude rarefactive ion acoustic solitary waves are associated with an increase in the width with increasing amplitude. This indicates that a weakly nonlinear theory is not appropriate to describe the solitary structures in the auroral regions. In the present work, a fully nonlinear analysis based on Sagdeev pseudopotential technique has been adopted for both parallel and oblique propagation of rarefactive solitary waves in a two electron temperature multi-ion plasma. The large amplitude solutions have consistently shown an increase in the width with increasing amplitude. The width-amplitude variation profile of obliquely propagating rarefactive solitary waves in a magnetized plasma have been compared with the recent POLAR observations. The width-amplitude variation pattern is found to fit well with the analytical results. It indicates that a fully nonlinear theory of ion acoustic solitary waves may well explain the observed anomalous width variations of large amplitude structures in the auroral region.

  12. Fast Preparation of Critical Ground States Using Superluminal Fronts

    Science.gov (United States)

    Agarwal, Kartiek; Bhatt, R. N.; Sondhi, S. L.

    2018-05-01

    We propose a spatiotemporal quench protocol that allows for the fast preparation of ground states of gapless models with Lorentz invariance. Assuming the system initially resides in the ground state of a corresponding massive model, we show that a superluminally moving "front" that locally quenches the mass, leaves behind it (in space) a state arbitrarily close to the ground state of the gapless model. Importantly, our protocol takes time O (L ) to produce the ground state of a system of size ˜Ld (d spatial dimensions), while a fully adiabatic protocol requires time ˜O (L2) to produce a state with exponential accuracy in L . The physics of the dynamical problem can be understood in terms of relativistic rarefaction of excitations generated by the mass front. We provide proof of concept by solving the proposed quench exactly for a system of free bosons in arbitrary dimensions, and for free fermions in d =1 . We discuss the role of interactions and UV effects on the free-theory idealization, before numerically illustrating the usefulness of the approach via simulations on the quantum Heisenberg spin chain.

  13. Variational Boussinesq model for simulation of coastal waves and tsunamis

    NARCIS (Netherlands)

    Adytia, D.; Adytia, Didit; van Groesen, Embrecht W.C.; Tan, Soon Keat; Huang, Zhenhua

    2009-01-01

    In this paper we describe the basic ideas of a so-called Variational Boussinesq Model which is based on the Hamiltonian structure of gravity surface waves. By using a rather simple approach to prescribe the profile of vertical fluid potential in the expression for the kinetic energy, we obtain a set

  14. Ground state energy of a polaron in a superlattice

    International Nuclear Information System (INIS)

    Mensah, S.Y.; Allotey, F.K.A.; Nkrumah, G.; Mensah, N.G.

    2000-10-01

    The ground state energy of a polaron in a superlattice was calculated using the double-time Green functions. The effective mass of the polaron along the planes perpendicular to the superlattice axis was also calculated. The dependence of the ground state energy and the effective mass along the planes perpendicular to the superlattice axis on the electron-phonon coupling constant α and on the superlattice parameters (i.e. the superlattice period d and the bandwidth Δ) were studied. It was observed that if an infinite square well potential is assumed, the ground state energy of the polaron decreases (i.e. becomes more negative) with increasing α and d, but increases with increasing Δ. For small values of α, the polaron ground state energy varies slowly with Δ, becoming approximately constant for large Δ. The effective mass along the planes perpendicular to the superlattice axis was found to be approximately equal to the mass of an electron for all typical values of α, d and Δ. (author)

  15. Trapping cold ground state argon atoms.

    Science.gov (United States)

    Edmunds, P D; Barker, P F

    2014-10-31

    We trap cold, ground state argon atoms in a deep optical dipole trap produced by a buildup cavity. The atoms, which are a general source for the sympathetic cooling of molecules, are loaded in the trap by quenching them from a cloud of laser-cooled metastable argon atoms. Although the ground state atoms cannot be directly probed, we detect them by observing the collisional loss of cotrapped metastable argon atoms and determine an elastic cross section. Using a type of parametric loss spectroscopy we also determine the polarizability of the metastable 4s[3/2](2) state to be (7.3±1.1)×10(-39)  C m(2)/V. Finally, Penning and associative losses of metastable atoms in the absence of light assisted collisions, are determined to be (3.3±0.8)×10(-10)  cm(3) s(-1).

  16. Correlated ground state and E2 giant resonance built on it

    International Nuclear Information System (INIS)

    Tohyama, Mitsuru

    1995-01-01

    Taking 16 O as an example of realistic nuclei, we demonstrate that a correlated ground state can be obtained as a long time solution of a time-dependent density-matrix formalism (TDDM) when the residual interaction is adiabatically treated. We also study in TDDM the E2 giant resonance of 16 O built on the correlated ground state and compare it with that built on the Hartree-Fock ground state. It is found that a spurious mixing of low frequency components seen in the latter is eliminated by using the correlated ground state. (author)

  17. Ground-Water Availability in the United States

    Science.gov (United States)

    Reilly, Thomas E.; Dennehy, Kevin F.; Alley, William M.; Cunningham, William L.

    2008-01-01

    Ground water is among the Nation's most important natural resources. It provides half our drinking water and is essential to the vitality of agriculture and industry, as well as to the health of rivers, wetlands, and estuaries throughout the country. Large-scale development of ground-water resources with accompanying declines in ground-water levels and other effects of pumping has led to concerns about the future availability of ground water to meet domestic, agricultural, industrial, and environmental needs. The challenges in determining ground-water availability are many. This report examines what is known about the Nation's ground-water availability and outlines a program of study by the U.S. Geological Survey Ground-Water Resources Program to improve our understanding of ground-water availability in major aquifers across the Nation. The approach is designed to provide useful regional information for State and local agencies who manage ground-water resources, while providing the building blocks for a national assessment. The report is written for a wide audience interested or involved in the management, protection, and sustainable use of the Nation's water resources.

  18. Back Radiation Suppression through a Semitransparent Ground Plane for a mm-Wave Patch Antenna

    KAUST Repository

    Klionovski, Kirill

    2017-06-21

    Omnidirectional radiation pattern with minimum backward radiation is highly desirable for base station antennas to minimize the multipath effects. Semitransparent ground planes have been used to reduce the backward radiation, but mostly with complicated non-uniform impedance distribution. In this work, we propose, for the first time, a round semitransparent ground plane of radius 0.8 λ with uniform impedance distribution that can improve the front-to-back ratio of a wideband patch antenna by 11.6 dB as compared to a similar sized metallic ground plane. The value of uniform impedance is obtained through analytical optimization by using asymptotic expressions in the Kirchhoff approximation of the radiation pattern of a toroidal wave scattered by a round semitransparent ground plane. The semitransparent ground plane has been realized using a low-cost carbon paste on a Kapton film. Experimental results match closely with those of simulations and validate the overall concept.

  19. Spatial and temporal variations of wave energy in the nearshore waters of the central west coast of India

    Science.gov (United States)

    Amrutha, M. M.; Sanil Kumar, V.

    2016-12-01

    Assessment of wave power potential at different water depths and time is required for identifying a wave power plant location. This study examines the variation in wave power off the central west coast of India at water depths of 30, 9 and 5 m based on waverider buoy measured wave data. The study shows a significant reduction ( ˜ 10 to 27 %) in wave power at 9 m water depth compared to 30 m and the wave power available at 5 m water depth is 20 to 23 % less than that at 9 m. At 9 m depth, the seasonal mean value of the wave power varied from 1.6 kW m-1 in the post-monsoon period (ONDJ) to 15.2 kW m-1 in the Indian summer monsoon (JJAS) period. During the Indian summer monsoon period, the variation of wave power in a day is up to 32 kW m-1. At 9 m water depth, the mean annual wave power is 6 kW m-1 and interannual variations up to 19.3 % are observed during 2009-2014. High wave energy ( > 20 kW m-1) at the study area is essentially from the directional sector 245-270° and also 75 % of the total annual wave energy is from this narrow directional sector, which is advantageous while aligning the wave energy converter.

  20. Coherent molecular transistor: control through variation of the gate wave function.

    Science.gov (United States)

    Ernzerhof, Matthias

    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.

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

    International Nuclear Information System (INIS)

    Ernzerhof, Matthias

    2014-01-01

    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

  2. The ground state energy of a classical gas

    International Nuclear Information System (INIS)

    Conlon, J.G.

    1983-01-01

    The ground state energy of a classical gas is treated using a probability function for the position of the particles and a potential function. The lower boundary for the energy when the particle number is large is defined as ground state energy. The coulomb gas consisting of positive and negative particles is also treated (fixed and variable density case) the stability of the relativistic system is investigated as well. (H.B.)

  3. Anomalous Ground State of the Electrons in Nano-confined Water

    Science.gov (United States)

    2016-06-13

    Anomalous ground state of the electrons in nano -confined water G. F. Reiter1*, Aniruddha Deb2*, Y. Sakurai3, M. Itou3, V. G. Krishnan4, S. J...electronic ground state of nano -confined water must be responsible for these anomalies but has so far not been investigated. We show here for the first time...using x-ray Compton scattering and a computational model, that the ground state configuration of the valence electrons in a particular nano

  4. A plane-wave final-state theory of ATI

    International Nuclear Information System (INIS)

    Parker, J.S.; Clark, C.W.

    1993-01-01

    A Fermi Golden Rule calculation of ionization cross-sections provides us with the simplest example of a plane-wave final-state theory. In this method the final (unbound) state is modeled as a plane wave, an approximation that generally gives best results in the high energy limit in which the affect of the atomic potential on the final state can be neglected. A cross-section is then calculated from the matrix element connecting the bound initial state with the final state. The idea of generalizing this method to model transitions among unbound states is credited to L.V. Keldysh, and a number of related formalisms have been proposed that are consistent with the general features of experimental data. Here we describe a plane-wave final-state model of ATI that is in the spirit of these theories, but differs significantly in its implementation and predictions. We will present a comparison of the predictions of the plane-wave model with those of a full numerical integration of the time-dependent Schrodinger equation for atomic hydrogen in a radiation field. The theory and the numerical integration give good qualitative agreement in their predictions of photoelectron spectra over about 14 orders of magnitude

  5. Rank restriction for the variational calculation of two-electron reduced density matrices of many-electron atoms and molecules

    International Nuclear Information System (INIS)

    Naftchi-Ardebili, Kasra; Hau, Nathania W.; Mazziotti, David A.

    2011-01-01

    Variational minimization of the ground-state energy as a function of the two-electron reduced density matrix (2-RDM), constrained by necessary N-representability conditions, provides a polynomial-scaling approach to studying strongly correlated molecules without computing the many-electron wave function. Here we introduce a route to enhancing necessary conditions for N representability through rank restriction of the 2-RDM. Rather than adding computationally more expensive N-representability conditions, we directly enhance the accuracy of two-particle (2-positivity) conditions through rank restriction, which removes degrees of freedom in the 2-RDM that are not sufficiently constrained. We select the rank of the particle-hole 2-RDM by deriving the ranks associated with model wave functions, including both mean-field and antisymmetrized geminal power (AGP) wave functions. Because the 2-positivity conditions are exact for quantum systems with AGP ground states, the rank of the particle-hole 2-RDM from the AGP ansatz provides a minimum for its value in variational 2-RDM calculations of general quantum systems. To implement the rank-restricted conditions, we extend a first-order algorithm for large-scale semidefinite programming. The rank-restricted conditions significantly improve the accuracy of the energies; for example, the percentages of correlation energies recovered for HF, CO, and N 2 improve from 115.2%, 121.7%, and 121.5% without rank restriction to 97.8%, 101.1%, and 100.0% with rank restriction. Similar results are found at both equilibrium and nonequilibrium geometries. While more accurate, the rank-restricted N-representability conditions are less expensive computationally than the full-rank conditions.

  6. Experimental and theoretical dipole moments of purines in their ground and lowest excited singlet states

    Science.gov (United States)

    Aaron, Jean-Jacques; Diabou Gaye, Mame; Párkányi, Cyril; Cho, Nam Sook; Von Szentpály, László

    1987-01-01

    The ground-state dipole moments of seven biologically important purines (purine, 6-chloropurine, 6-mercaptopurine, hypoxanthine, theobromine, theophylline and caffeine) were determined at 25°C in acetic acid (all the above compounds with the exception of purine) and in ethyl acetate (purine, theophylline and caffeine). Because of its low solubility, it was not possible to measure the dipole moment of uric acid. The first excited singlet-state dipole moments were obtained on the basis of the Bakhshiev and Chamma—Viallet equations using the variation of the Stokes shift with the solvent dielectric constant-refractive index term. The theoretical dipole moments for all the purines listed above and including uric acid were calculated by combining the use of the PPP (π-LCI-SCF-MO) method for the π-contribution to the overall dipole moment with the σ-contribution obtained as a vector sum of the σbond moments and group moments. The experimental and theoretical values were compared with the data available in the literature for some of the purines under study. For several purines, the calculations were carried out for different tautomeric forms. Excited singlet-state dipole moments are smaller than the ground-state values by 0.8 to 2.2 Debye units for all purines under study with the exception of 6-chloropurine. The effects of the structure upon the ground- and excited-state dipole moments of the purines are discussed.

  7. Solving satisfiability problems by the ground-state quantum computer

    International Nuclear Information System (INIS)

    Mao Wenjin

    2005-01-01

    A quantum algorithm is proposed to solve the satisfiability (SAT) problems by the ground-state quantum computer. The scale of the energy gap of the ground-state quantum computer is analyzed for the 3-bit exact cover problem. The time cost of this algorithm on the general SAT problems is discussed

  8. Gravitational-Wave Tests of General Relativity with Ground-Based Detectors and Pulsar-Timing Arrays

    Directory of Open Access Journals (Sweden)

    Nicolás Yunes

    2013-11-01

    Full Text Available This review is focused on tests of Einstein's theory of general relativity with gravitational waves that are detectable by ground-based interferometers and pulsar-timing experiments. Einstein’s theory has been greatly constrained in the quasi-linear, quasi-stationary regime, where gravity is weak and velocities are small. Gravitational waves will allow us to probe a complimentary, yet previously unexplored regime: the non-linear and dynamical strong-field regime. Such a regime is, for example, applicable to compact binaries coalescing, where characteristic velocities can reach fifty percent the speed of light and gravitational fields are large and dynamical. This review begins with the theoretical basis and the predicted gravitational-wave observables of modified gravity theories. The review continues with a brief description of the detectors, including both gravitational-wave interferometers and pulsar-timing arrays, leading to a discussion of the data analysis formalism that is applicable for such tests. The review ends with a discussion of gravitational-wave tests for compact binary systems.

  9. Gravitational-Wave Tests of General Relativity with Ground-Based Detectors and Pulsar-Timing Arrays.

    Science.gov (United States)

    Yunes, Nicolás; Siemens, Xavier

    2013-01-01

    This review is focused on tests of Einstein's theory of general relativity with gravitational waves that are detectable by ground-based interferometers and pulsar-timing experiments. Einstein's theory has been greatly constrained in the quasi-linear, quasi-stationary regime, where gravity is weak and velocities are small. Gravitational waves will allow us to probe a complimentary, yet previously unexplored regime: the non-linear and dynamical strong-field regime . Such a regime is, for example, applicable to compact binaries coalescing, where characteristic velocities can reach fifty percent the speed of light and gravitational fields are large and dynamical. This review begins with the theoretical basis and the predicted gravitational-wave observables of modified gravity theories. The review continues with a brief description of the detectors, including both gravitational-wave interferometers and pulsar-timing arrays, leading to a discussion of the data analysis formalism that is applicable for such tests. The review ends with a discussion of gravitational-wave tests for compact binary systems.

  10. State-in-the-art of applications of shock wave research and its future; Shogekiha no oyo gijutsu no genjo to shorai

    Energy Technology Data Exchange (ETDEWEB)

    Takayama, K. [Tohoku Univ., Sendai (Japan). Inst. of Fluid Science

    1999-03-15

    A shock wave appears when the release of accumulated energy is instantaneous. For instance, it accompanies gunpowder explosion, electric discharge, laser beam convergence, collision of high-speed objects, release of high-pressure gas, and supersonic flight. The shock wave research center of Institute of Fluid Science, Tohoku University, is engaged in researches to elucidate the basics of various shock wave phenomena and to apply the fruit to engineering, science, and medicine. In this report, some examples of recent application studies at the center are described, and the trend of shock wave researches in the future is introduced. The ultimate state of the stagnation point of a nozzle flow simulating a reentry into the atmosphere is produced by shock wave compression in a free piston shock tube which is a ground-borne experimental apparatus. Los Alamos National Laboratory, U.S., succeeded in generating metallic hydrogen of a crystalline structure by subjecting liquid hydrogen to shock wave compression, in which effort a two-stage light gas gun augmented with an accelerator was operated. A high-performance two-stage light gas gun can simulate on the ground a collision of space debris in a high vacuum. Other researches involve the elucidation of the mechanism of sonic noise. (NEDO)

  11. Variations in radon-222 in soil and ground water at the Nevada Test Site

    International Nuclear Information System (INIS)

    Wollenberg, H.; Straume, T.; Smith, A.; King, C.Y.

    1977-01-01

    To help evaluate the applicability of variations of radon-222 in ground water and soil gas as a possible earthquake predictor, measurements were conducted in conjunction with underground explosions at the Nevada Test Site (NTS). Radon fluctuations in ground water have been observed during a sequence of aftershocks following the Oroville, California earthquake of 1 August 1975. The NTS measurements were designed to show if these fluctuations were in response to ground shaking; if not, they could be attributed to changes in earth strain prior to the aftershocks. Well waters were periodically sampled and soil-gas 222 Rn monitored prior to and following seven underground explosions of varying strength and distance from sampling and detector locations. Soil-gas 222 Rn contents were measured by the alpha-track method; well water 222 Rn by gamma-ray spectrometry. There was no clearly identifiable correlation between well-water radon fluctuations and individual underground tests. One prominent variation in soil-gas radon corresponded to ground shaking from a pair of underground tests in alluvium; otherwise, there was no apparent correlation between radon emanation and other explosions. Markedly lower soil-gas radon contents following the tests were probably caused by consolidation of alluvium in response to ground shaking

  12. High Fidelity Preparation of a Single Atom in Its 2D Center of Mass Ground State

    Science.gov (United States)

    Sompet, Pimonpan; Fung, Yin Hsien; Schwartz, Eyal; Hunter, Matthew D. J.; Phrompao, Jindaratsamee; Andersen, Mikkel F.

    2017-04-01

    Complete control over quantum states of individual atoms is important for the study of the microscopic world. Here, we present a push button method for high fidelity preparation of a single 85Rb atom in the vibrational ground state of tightly focused optical tweezers. The method combines near-deterministic preparation of a single atom with magnetically-insensitive Raman sideband cooling. We achieve 2D cooling in the radial plane with a ground state population of 0.85, which provides a fidelity of 0.7 for the entire procedure (loading and cooling). The Raman beams couple two sublevels (| F = 3 , m = 0 〉 and | F = 2 , m = 0 〉) that are indifferent to magnetic noise to first order. This leads to long atomic coherence times, and allows us to implement the cooling in an environment where magnetic field fluctuations prohibit previously demonstrated variations. Additionally, we implement the trapping and manipulation of two atoms confined in separate dynamically reconfigurable optical tweezers, to study few-body dynamics.

  13. Quasi-biennial variation of equatorial waves as seen in satellite remote sensing data

    Science.gov (United States)

    Chen, Zeyu

    The quasi-biennial oscillation (QBO) in zonal winds in the lower stratosphere at the Equator is the most prominent inter-annual variation signal in the middle atmosphere. Theoretically, it is driven by the drag from the damping of equatorial waves including the equatorially trapped planetary scale waves, such as Kelvin waves propagating eastward and Rossby-gravity waves propagating westward, inertio-gravity waves and gravity waves. In current research, the tem-perature data collected by the SABER/TIMED mission in 2002-2009 are used to investigate the equatorial waves activities. The Fast Fourier Synoptic Mapping (FFSM) method is applied to delineate planetary wave components with the zonal wavenumber spanning over -6 to +6, hereby, positive (negative) wavenumber is assigned to westward (eastward) propagating waves. Limited by the SABER/TIMED sampling scheme, only the waves with periods longer than one day can be resolved. Focusing on the height region 70-10 hPa where the QBO signal is most significant, it is clearly observed that the composite activity of all the eastward waves exhibit QBO like variation. Specifically, for each QBO cycle, the activity at 50 hPa level is characterized by the occurrence of a substantially clear minimum that coincides to the fast downward propagation of the westerly phase, the typical pattern of the QBO phenomenon. Phase speed spectra are derived by using the FFSM analysis results. And vertical shear of the zonal wind is derived by using the rawinsonde data at Singapore. Comparison of the phase speed spectra and the wind shear indicates that the minimum is due to the westerly shear below 30 hPa. Between the minimum, significant wave activities emerge, thus the property for the components are investigated. Results show that in height range 70-10 hPa, both wave 1 to wave 3 are prominent during the inter-minimum period for each QBO cycle. At 50 hPa level, wave 1 component exhibits amplitude spectral peak at three kinds of period, 8, 11

  14. Relativistic bound state wave functions

    International Nuclear Information System (INIS)

    Micu, L.

    2005-01-01

    A particular method of writing the bound state wave functions in relativistic form is applied to the solutions of the Dirac equation with confining potentials in order to obtain a relativistic description of a quark antiquark bound system representing a given meson. Concerning the role of the effective constituent in the present approach we first observe that without this additional constituent we couldn't expand the bound state wave function in terms of products of free states. Indeed, we notice that if the wave function depends on the relative coordinates only, all the expansion coefficients would be infinite. Secondly we remark that the effective constituent enabled us to give a Lorentz covariant meaning to the potential energy of the bound system which is now seen as the 4th component of a 4-momentum. On the other side, by relating the effective constituent to the quantum fluctuations of the background field which generate the binding, we provided a justification for the existence of some spatial degrees of freedom accompanying the interaction potential. These ones, which are quite unusual in quantum mechanics, in our model are the natural consequence of the the independence of the quarks and can be seen as the effect of the imperfect cancellation of the vector momenta during the quantum fluctuations. Related with all these we remark that the adequate representation for the relativistic description of a bound system is the momentum representation, because of the transparent and easy way of writing the conservation laws and the transformation properties of the wave functions. The only condition to be fulfilled is to find a suitable way to take into account the potential energy of the bound system. A particular feature of the present approach is that the confining forces are due to a kind of glue where both quarks are embedded. This recalls other bound state models where the wave function is factorized in terms of constituent wave functions and the confinement is

  15. Ground state energy fluctuations in the nuclear shell model

    International Nuclear Information System (INIS)

    Velazquez, Victor; Hirsch, Jorge G.; Frank, Alejandro; Barea, Jose; Zuker, Andres P.

    2005-01-01

    Statistical fluctuations of the nuclear ground state energies are estimated using shell model calculations in which particles in the valence shells interact through well-defined forces, and are coupled to an upper shell governed by random 2-body interactions. Induced ground-state energy fluctuations are found to be one order of magnitude smaller than those previously associated with chaotic components, in close agreement with independent perturbative estimates based on the spreading widths of excited states

  16. Spatial and temporal variation of surface waves in shallow waters along the eastern Arabian Sea.

    Digital Repository Service at National Institute of Oceanography (India)

    Anoop, T.R.; SanilKumar, V.; Shanas, P.R.

    We studied the spatial and temporal variation of surface waves along the eastern Arabian Sea during 2011 and 2012. Measured directional wave data at two shallow water locations and re-analysis datasets (ERA-Interim) at 0.751 intervals at four...

  17. Unitary Dynamics of Strongly Interacting Bose Gases with the Time-Dependent Variational Monte Carlo Method in Continuous Space

    Science.gov (United States)

    Carleo, Giuseppe; Cevolani, Lorenzo; Sanchez-Palencia, Laurent; Holzmann, Markus

    2017-07-01

    We introduce the time-dependent variational Monte Carlo method for continuous-space Bose gases. Our approach is based on the systematic expansion of the many-body wave function in terms of multibody correlations and is essentially exact up to adaptive truncation. The method is benchmarked by comparison to an exact Bethe ansatz or existing numerical results for the integrable Lieb-Liniger model. We first show that the many-body wave function achieves high precision for ground-state properties, including energy and first-order as well as second-order correlation functions. Then, we study the out-of-equilibrium, unitary dynamics induced by a quantum quench in the interaction strength. Our time-dependent variational Monte Carlo results are benchmarked by comparison to exact Bethe ansatz results available for a small number of particles, and are also compared to quench action results available for noninteracting initial states. Moreover, our approach allows us to study large particle numbers and general quench protocols, previously inaccessible beyond the mean-field level. Our results suggest that it is possible to find correlated initial states for which the long-term dynamics of local density fluctuations is close to the predictions of a simple Boltzmann ensemble.

  18. Using Uncertainty Principle to Find the Ground-State Energy of the Helium and a Helium-like Hookean Atom

    Science.gov (United States)

    Harbola, Varun

    2011-01-01

    In this paper, we accurately estimate the ground-state energy and the atomic radius of the helium atom and a helium-like Hookean atom by employing the uncertainty principle in conjunction with the variational approach. We show that with the use of the uncertainty principle, electrons are found to be spread over a radial region, giving an electron…

  19. Exact ground and excited states of an antiferromagnetic quantum spin model

    International Nuclear Information System (INIS)

    Bose, I.

    1989-08-01

    A quasi-one-dimensional spin model which consists of a chain of octahedra of spins has been suggested for which a certain parameter regime of the Hamiltonian, the ground state, can be written down exactly. The ground state is highly degenerate and can be other than a singlet. Also, several excited states can be constructed exactly. The ground state is a local RVB state for which resonance is confined to rings of spins. Some exact numerical results for an octahedron of spins have also been reported. (author). 16 refs, 2 figs, 1 tab

  20. Extended random-phase approximation with three-body ground-state correlations

    International Nuclear Information System (INIS)

    Tohyama, M.; Schuck, P.

    2008-01-01

    An extended random-phase approximation (ERPA) which contains the effects of ground-state correlations up to a three-body level is applied to an extended Lipkin model which contains an additional particle-scattering term. Three-body correlations in the ground state are necessary to preserve the hermiticity of the Hamiltonian matrix of ERPA. Two approximate forms of ERPA which neglect the three-body correlations are also applied to investigate the importance of three-body correlations. It is found that the ground-state energy is little affected by the inclusion of the three-body correlations. On the contrary, three-body correlations for the excited states can become quite important. (orig.)

  1. Satellite and Ground Signatures of Kinetic and Inertial Scale ULF Alfven Waves Propagating in Warm Plasma in Earth's Magnetosphere

    Science.gov (United States)

    Rankin, R.; Sydorenko, D.

    2015-12-01

    Results from a 3D global numerical model of Alfven wave propagation in a warm multi-species plasma in Earth's magnetosphere are presented. The model uses spherical coordinates, accounts for a non-dipole magnetic field, vertical structure of the ionosphere, and an air gap below the ionosphere. A realistic density model is used. Below the exobase altitude (2000 km) the densities and the temperatures of electrons, ions, and neutrals are obtained from the IRI and MSIS models. Above the exobase, ballistic (originating from the ionosphere and returning to ionosphere) and trapped (bouncing between two reflection points above the ionosphere) electron populations are considered similar to [Pierrard and Stegen (2008), JGR, v.113, A10209]. Plasma parameters at the exobase provided by the IRI are the boundary conditions for the ballistic electrons while the [Carpenter and Anderson (1992), JGR, v.97, p.1097] model of equatorial electron density defines parameters of the trapped electron population. In the simulations that are presented, Alfven waves with frequencies from 1 Hz to 0.01 Hz and finite azimuthal wavenumbers are excited in the magnetosphere and compared with Van Allen Probes data and ground-based observations from the CARISMA array of ground magnetometers. When short perpendicular scale waves reflect form the ionosphere, compressional Alfven waves are observed to propagate across the geomagnetic field in the ionospheric waveguide [e.g., Lysak (1999), JGR, v.104, p.10017]. Signals produced by the waves on the ground are discussed. The wave model is also applied to interpret recent Van Allen Probes observations of kinetic scale ULF waves that are associated with radiation belt electron dynamics and energetic particle injections.

  2. Theory of Spin Waves in Strongly Anisotropic Magnets

    DEFF Research Database (Denmark)

    Lindgård, Per-Anker; Cooke, J. F.

    1976-01-01

    A new infinite-order perturbation approach to the theory of spin waves in strongly anisotropic magnets is introduced. The system is transformed into one with effective two-ion anisotropy and considerably reduced ground-state corrections. A general expression for the spin-wave energy, valid to any...

  3. Millimeter Wave Spectrum of the Two Monosulfur Derivatives of Methyl Formate: s- and O-Methyl Thioformate, in the Ground and the First Excited Torsional States

    Science.gov (United States)

    Jabri, Atef; Motiyenko, R. A.; Margulès, L.; Guillemin, J.-C.; Alekseev, E. A.; Kleiner, Isabelle; Tercero, Belén; Cernicharo, Jose

    2017-06-01

    Methyl formate CH_{3}OC(O)H is a relatively abundant component of the interstellar medium (ISM). Thus, we decided to study its sulfur derivatives as they can be reasonably proposed for detection in the ISM. In fact there is two relatively stable isomers for methyl thioformate, S-Methyl thioformate CH_{3}SC(O)H and O-Methyl thiofomate CH_{3}OC(S)H. Theoretical investigations on these molecules have been done recently by Senent et al.. Previous experimental investigations were performed only for the S-Methyl thioformate in the 10-41 GHz spectral range by Jones et al. and Caminati et al.. For the present study both isomers were synthesized and the millimeter wave spectrum was then recorded for the first time from 150 to 660 GHz with the Lille's spectrometer based on solid-state sources. The internal rotation effect on the millimeter wave spectra is not the same for these two molecules because the barrier height to internal rotation is relatively low for the S- isomer (V_{3} ≈ 140 \\wn) and rather high for the O- isomer (V_{3} ≈ 700 \\wn). Analysis of the ground and excited torsional states performed with the BELGI-C_{s} code will be presented and discussed. We will provide the search for methyl thioformate in different sources. E. Chruchwell, G. Winnewisser, A&A, 45, 229 (1975) M. L. Senent, C. Puzzarini, M. Hochlaf, R. Dominguez-Gomez, and M. Carvajal, J. Chem. Phys., 141, 104303 (2014) G. I. L. Jones, D. G. Lister, N. L. Owen, J. Mol. Spectrosc., 60, 348 (1976) W. Caminati, B. P. V. Eijck, D. G. Lister, J. Mol. Spectrosc., 90, 15 (1981) J. T. Hougen, I. Kleiner, and M. Godefroid, J. Mol. Spectrosc. 163, 559 (1994)

  4. Ground-Water Flow Model of the Sierra Vista Subwatershed and Sonoran Portions of the Upper San Pedro Basin, Southeastern Arizona, United States, and Northern Sonora, Mexico

    Science.gov (United States)

    Pool, D.R.; Dickinson, Jesse

    2007-01-01

    A numerical ground-water model was developed to simulate seasonal and long-term variations in ground-water flow in the Sierra Vista subwatershed, Arizona, United States, and Sonora, Mexico, portions of the Upper San Pedro Basin. This model includes the simulation of details of the groundwater flow system that were not simulated by previous models, such as ground-water flow in the sedimentary rocks that surround and underlie the alluvial basin deposits, withdrawals for dewatering purposes at the Tombstone mine, discharge to springs in the Huachuca Mountains, thick low-permeability intervals of silt and clay that separate the ground-water flow system into deep-confined and shallow-unconfined systems, ephemeral-channel recharge, and seasonal variations in ground-water discharge by wells and evapotranspiration. Steady-state and transient conditions during 1902-2003 were simulated by using a five-layer numerical ground- water flow model representing multiple hydrogeologic units. Hydraulic properties of model layers, streamflow, and evapotranspiration rates were estimated as part of the calibration process by using observed water levels, vertical hydraulic gradients, streamflow, and estimated evapotranspiration rates as constraints. Simulations approximate observed water-level trends throughout most of the model area and streamflow trends at the Charleston streamflow-gaging station on the San Pedro River. Differences in observed and simulated water levels, streamflow, and evapotranspiration could be reduced through simulation of climate-related variations in recharge rates and recharge from flood-flow infiltration.

  5. Spatial and temporal variations of wave energy in the nearshore waters of the central west coast of India

    Directory of Open Access Journals (Sweden)

    M. M. Amrutha

    2016-12-01

    Full Text Available Assessment of wave power potential at different water depths and time is required for identifying a wave power plant location. This study examines the variation in wave power off the central west coast of India at water depths of 30, 9 and 5 m based on waverider buoy measured wave data. The study shows a significant reduction ( ∼  10 to 27 % in wave power at 9 m water depth compared to 30 m and the wave power available at 5 m water depth is 20 to 23 % less than that at 9 m. At 9 m depth, the seasonal mean value of the wave power varied from 1.6 kW m−1 in the post-monsoon period (ONDJ to 15.2 kW m−1 in the Indian summer monsoon (JJAS period. During the Indian summer monsoon period, the variation of wave power in a day is up to 32 kW m−1. At 9 m water depth, the mean annual wave power is 6 kW m−1 and interannual variations up to 19.3 % are observed during 2009–2014. High wave energy ( >  20 kW m−1 at the study area is essentially from the directional sector 245–270° and also 75 % of the total annual wave energy is from this narrow directional sector, which is advantageous while aligning the wave energy converter.

  6. Accuracy of three-body wave functions obtained with the correlation-function hyperspherical-harmonic method

    International Nuclear Information System (INIS)

    Haftel, M.I.; Mandelzweig, V.B.

    1990-01-01

    The local convergence and accuracy of wave functions obtained by direct solution of the Schroedinger equation with the help of the correlation-function hyperspherical-harmonic method are analyzed for ground and excited states of the helium atom and for the ground state of the positronium negative ion. The inclusion of the cusp conditions into the correlation function is shown to be of crucial importance, not only near the coalescence points, but also away from them. The proper inclusion of all cusps yields for the ground state of the helium atom the local wave-function accuracy of about 10 -7 for different interparticle distances. The omission of one of the cusps in the excited helium atom reduces the wave-function precision to 10 -2 near the corresponding coalescence point and to 10 -4 --10 -5 away from it

  7. Magnetostriction-driven ground-state stabilization in 2H perovskites

    International Nuclear Information System (INIS)

    Porter, D. G.; Senn, M. S.; University of Oxford; Khalyavin, D. D.; Cortese, A.

    2016-01-01

    In this paper, the magnetic ground state of Sr_3ARuO_6, with A =(Li,Na), is studied using neutron diffraction, resonant x-ray scattering, and laboratory characterization measurements of high-quality crystals. Combining these results allows us to observe the onset of long-range magnetic order and distinguish the symmetrically allowed magnetic models, identifying in-plane antiferromagnetic moments and a small ferromagnetic component along the c axis. While the existence of magnetic domains masks the particular in-plane direction of the moments, it has been possible to elucidate the ground state using symmetry considerations. We find that due to the lack of local anisotropy, antisymmetric exchange interactions control the magnetic order, first through structural distortions that couple to in-plane antiferromagnetic moments and second through a high-order magnetoelastic coupling that lifts the degeneracy of the in-plane moments. Finally, the symmetry considerations used to rationalize the magnetic ground state are very general and will apply to many systems in this family, such as Ca_3ARuO_6, with A = (Li,Na), and Ca_3LiOsO_6 whose magnetic ground states are still not completely understood.

  8. Ground-Wave Propagation Effects on Transmission Lines through Error Images

    Directory of Open Access Journals (Sweden)

    Uribe-Campos Felipe Alejandro

    2014-07-01

    Full Text Available Electromagnetic transient calculation of overhead transmission lines is strongly influenced by the natural resistivity of the ground. This varies from 1-10K (Ω·m depending on several media factors and on the physical composition of the ground. The accuracy on the calculation of a system transient response depends in part in the ground return model, which should consider the line geometry, the electrical resistivity and the frequency dependence of the power source. Up to date, there are only a few reports on the specialized literature about analyzing the effects produced by the presence of an imperfectly conducting ground of transmission lines in a transient state. A broad range analysis of three of the most often used ground-return models for calculating electromagnetic transients of overhead transmission lines is performed in this paper. The behavior of modal propagation in ground is analyzed here into effects of first and second order. Finally, a numerical tool based on relative error images is proposed in this paper as an aid for the analyst engineer to estimate the incurred error by using approximate ground-return models when calculating transients of overhead transmission lines.

  9. The relation between the (N) and (N-1) electrons atomic ground state

    International Nuclear Information System (INIS)

    Briet, P.

    1984-05-01

    The relation between the ground state of an N and (N-1) electrons atomic system are studied. We show that in some directions of the configuration space, the ratio of the N electrons atomic ground state to the one particle density is asymptotically equivalent to the (N-1) electrons atomic ground state

  10. Degenerate ground states and multiple bifurcations in a two-dimensional q-state quantum Potts model.

    Science.gov (United States)

    Dai, Yan-Wei; Cho, Sam Young; Batchelor, Murray T; Zhou, Huan-Qiang

    2014-06-01

    We numerically investigate the two-dimensional q-state quantum Potts model on the infinite square lattice by using the infinite projected entangled-pair state (iPEPS) algorithm. We show that the quantum fidelity, defined as an overlap measurement between an arbitrary reference state and the iPEPS ground state of the system, can detect q-fold degenerate ground states for the Z_{q} broken-symmetry phase. Accordingly, a multiple bifurcation of the quantum ground-state fidelity is shown to occur as the transverse magnetic field varies from the symmetry phase to the broken-symmetry phase, which means that a multiple-bifurcation point corresponds to a critical point. A (dis)continuous behavior of quantum fidelity at phase transition points characterizes a (dis)continuous phase transition. Similar to the characteristic behavior of the quantum fidelity, the magnetizations, as order parameters, obtained from the degenerate ground states exhibit multiple bifurcation at critical points. Each order parameter is also explicitly demonstrated to transform under the Z_{q} subgroup of the symmetry group of the Hamiltonian. We find that the q-state quantum Potts model on the square lattice undergoes a discontinuous (first-order) phase transition for q=3 and q=4 and a continuous phase transition for q=2 (the two-dimensional quantum transverse Ising model).

  11. A Numerical Study on the Screening of Blast-Induced Waves for Reducing Ground Vibration

    Science.gov (United States)

    Park, Dohyun; Jeon, Byungkyu; Jeon, Seokwon

    2009-06-01

    Blasting is often a necessary part of mining and construction operations, and is the most cost-effective way to break rock, but blasting generates both noise and ground vibration. In urban areas, noise and vibration have an environmental impact, and cause structural damage to nearby structures. Various wave-screening methods have been used for many years to reduce blast-induced ground vibration. However, these methods have not been quantitatively studied for their reduction effect of ground vibration. The present study focused on the quantitative assessment of the effectiveness in vibration reduction of line-drilling as a screening method using a numerical method. Two numerical methods were used to analyze the reduction effect toward ground vibration, namely, the “distinct element method” and the “non-linear hydrocode.” The distinct element method, by particle flow code in two dimensions (PFC 2D), was used for two-dimensional parametric analyses, and some cases of two-dimensional analyses were analyzed three-dimensionally using AUTODYN 3D, the program of the non-linear hydrocode. To analyze the screening effectiveness of line-drilling, parametric analyses were carried out under various conditions, with the spacing, diameter of drill holes, distance between the blasthole and line-drilling, and the number of rows of drill holes, including their arrangement, used as parameters. The screening effectiveness was assessed via a comparison of the vibration amplitude between cases both with and without screening. Also, the frequency distribution of ground motion of the two cases was investigated through fast Fourier transform (FFT), with the differences also examined. From our study, it was concluded that line-drilling as a screening method of blast-induced waves was considerably effective under certain design conditions. The design details for field application have also been proposed.

  12. Coherent Control of Ground State NaK Molecules

    Science.gov (United States)

    Yan, Zoe; Park, Jee Woo; Loh, Huanqian; Will, Sebastian; Zwierlein, Martin

    2016-05-01

    Ultracold dipolar molecules exhibit anisotropic, tunable, long-range interactions, making them attractive for the study of novel states of matter and quantum information processing. We demonstrate the creation and control of 23 Na40 K molecules in their rovibronic and hyperfine ground state. By applying microwaves, we drive coherent Rabi oscillations of spin-polarized molecules between the rotational ground state (J=0) and J=1. The control afforded by microwave manipulation allows us to pursue engineered dipolar interactions via microwave dressing. By driving a two-photon transition, we are also able to observe Ramsey fringes between different J=0 hyperfine states, with coherence times as long as 0.5s. The realization of long coherence times between different molecular states is crucial for applications in quantum information processing. NSF, AFOSR- MURI, Alfred P. Sloan Foundation, DARPA-OLE

  13. Submillimeter-wave and far-infrared spectroscopy of high-J transitions of the ground and ν2 = 1 states of ammonia.

    Science.gov (United States)

    Yu, Shanshan; Pearson, John C; Drouin, Brian J; Sung, Keeyoon; Pirali, Olivier; Vervloet, Michel; Martin-Drumel, Marie-Aline; Endres, Christian P; Shiraishi, Tetsuro; Kobayashi, Kaori; Matsushima, Fusakazu

    2010-11-07

    Complete and reliable knowledge of the ammonia spectrum is needed to enable the analysis and interpretation of astrophysical and planetary observations. Ammonia has been observed in the interstellar medium up to J=18 and more highly excited transitions are expected to appear in hot exoplanets and brown dwarfs. As a result, there is considerable interest in observing and assigning the high J (rovibrational) spectrum. In this work, numerous spectroscopic techniques were employed to study its high J transitions in the ground and ν(2)=1 states. Measurements were carried out using a frequency multiplied submillimeter spectrometer at Jet Propulsion Laboratory (JPL), a tunable far-infrared spectrometer at University of Toyama, and a high-resolution Bruker IFS 125 Fourier transform spectrometer (FTS) at Synchrotron SOLEIL. Highly excited ammonia was created with a radiofrequency discharge and a dc discharge, which allowed assignments of transitions with J up to 35. One hundred and seventy seven ground state and ν(2)=1 inversion transitions were observed with microwave accuracy in the 0.3-4.7 THz region. Of these, 125 were observed for the first time, including 26 ΔK=3 transitions. Over 2000 far-infrared transitions were assigned to the ground state and ν(2)=1 inversion bands as well as the ν(2) fundamental band. Of these, 1912 were assigned using the FTS data for the first time, including 222 ΔK=3 transitions. The accuracy of these measurements has been estimated to be 0.0003-0.0006 cm(-1). A reduced root mean square error of 0.9 was obtained for a global fit of the ground and ν(2)=1 states, which includes the lines assigned in this work and all previously available microwave, terahertz, far-infrared, and mid-infrared data. The new measurements and predictions reported here will support the analyses of astronomical observations by high-resolution spectroscopy telescopes such as Herschel, SOFIA, and ALMA. The comprehensive experimental rovibrational energy levels

  14. Experimental Insights into Ground-State Selection of Quantum XY Pyrochlores

    Science.gov (United States)

    Hallas, Alannah M.; Gaudet, Jonathan; Gaulin, Bruce D.

    2018-03-01

    Extensive experimental investigations of the magnetic structures and excitations in the XY pyrochlores have been carried out over the past decade. Three families of XY pyrochlores have emerged: Yb2B2O7, Er2B2O7, and, most recently, [Formula: see text]Co2F7. In each case, the magnetic cation (either Yb, Er, or Co) exhibits XY anisotropy within the local pyrochlore coordinates, a consequence of crystal field effects. Materials in these families display rich phase behavior and are candidates for exotic ground states, such as quantum spin ice, and exotic ground-state selection via order-by-disorder mechanisms. In this review, we present an experimental summary of the ground-state properties of the XY pyrochlores, including evidence that they are strongly influenced by phase competition. We empirically demonstrate the signatures for phase competition in a frustrated magnet: multiple heat capacity anomalies, suppressed TN or TC, sample- and pressure-dependent ground states, and unconventional spin dynamics.

  15. Stochastic variational approach to minimum uncertainty states

    Energy Technology Data Exchange (ETDEWEB)

    Illuminati, F.; Viola, L. [Dipartimento di Fisica, Padova Univ. (Italy)

    1995-05-21

    We introduce a new variational characterization of Gaussian diffusion processes as minimum uncertainty states. We then define a variational method constrained by kinematics of diffusions and Schroedinger dynamics to seek states of local minimum uncertainty for general non-harmonic potentials. (author)

  16. Variational calculations in gauge theories with approximate projection on gauge invariant states

    International Nuclear Information System (INIS)

    Heinemann, C.; Martin, C.; Vautherin, D.; Iancu, E.

    1999-01-01

    Variational calculations using Gaussian wave functionals combined with an approximate projection on gauge invariant states are presented. The minimization with respect to the kernel and center of the Gaussian leads to a gap type equation which is free of the difficulties generally encountered with negative modes. We show that the divergences in the expectation value of the energy density are only logarithmic and can be removed by a renormalization of the coupling constant. The renormalized energy density has a minimum which corresponds to a vanishing background magnetic field. We obtain an estimate for the gluon condensate. (authors)

  17. Earthquake ground-motion in presence of source and medium heterogeneities

    KAUST Repository

    Vyas, Jagdish Chandra

    2017-01-01

    This dissertation work investigates the effects of earthquake rupture complexity and heterogeneities in Earth structure on near-field ground-motions. More specifically, we address two key issues in seismology: (1) near-field ground-shaking variability as function of distance and azimuth for unilateral directive ruptures, and (2) impact of rupture complexity and seismic scattering on Mach wave coherence associated with supershear rupture propagation. We examine earthquake ground-motion variability associated with unilateral ruptures based on ground-motion simulations of the MW 7.3 1992 Landers earthquake, eight simplified source models, and a MW 7.8 rupture simulation (ShakeOut) for the San Andreas fault. Our numerical modeling reveals that the ground-shaking variability in near-fault distances (< 20 km) is larger than that given by empirical ground motion prediction equations. In addition, the variability decreases with increasing distance from the source, exhibiting a power-law decay. The high near-field variability can be explained by strong directivity effects whose influence weaken as we move away from the fault. At the same time, the slope of the power-law decay is found to be dominantly controlled by slip heterogeneity. Furthermore, the ground-shaking variability is high in the rupture propagation direction whereas low in the directions perpendicular to it. However, the variability expressed as a function of azimuth is not only sensitive to slip heterogeneity, but also to rupture velocity. To study Mach wave coherence for supershear ruptures, we consider heterogeneities in rupture parameters (variations in slip, rise time and rupture speed) and 3D scattering media having small-scale random heterogeneities. The Mach wave coherence is reduced at near-fault distances (< 10 km) by the source heterogeneities. At the larger distances from the source, medium scattering plays the dominant role in reducing the Mach wave coherence. Combined effect of the source and

  18. Ground Motion Prediction Equations for the Central and Eastern United States

    Science.gov (United States)

    Seber, D.; Graizer, V.

    2015-12-01

    New ground motion prediction equations (GMPE) G15 model for the Central and Eastern United States (CEUS) is presented. It is based on the modular filter based approach developed by Graizer and Kalkan (2007, 2009) for active tectonic environment in the Western US (WUS). The G15 model is based on the NGA-East database for the horizontal peak ground acceleration and 5%-damped pseudo spectral acceleration RotD50 component (Goulet et al., 2014). In contrast to active tectonic environment the database for the CEUS is not sufficient for creating purely empirical GMPE covering the range of magnitudes and distances required for seismic hazard assessments. Recordings in NGA-East database are sparse and cover mostly range of Mindustry (Vs=2800 m/s). The number of model predictors is limited to a few measurable parameters: moment magnitude M, closest distance to fault rupture plane R, average shear-wave velocity in the upper 30 m of the geological profile VS30, and anelastic attenuation factor Q0. Incorporating anelastic attenuation Q0 as an input parameter allows adjustments based on the regional crustal properties. The model covers the range of magnitudes 4.010 Hz) and is within the range of other models for frequencies lower than 2.5 Hz

  19. Gutzwiller variational wave function for a two-orbital Hubbard model on a square lattice

    Energy Technology Data Exchange (ETDEWEB)

    Muenster, Kevin Torben zu

    2015-07-01

    freedom of the Gutzwiller correlator. Furthermore, we discussed the implications of this parameter gauge for a more general setup. The big advantage of our diagrammatic approach lies in the fact that it simplifies decisively in the limit of infinite spatial dimensions. We obtain the exact result for Gutzwiller expectation values of single-site and two-site operators without calculating a single, non-trivial diagram. Of course, the diagrams with internal vertices contribute in finite dimensions, and their importance for phase transitions and the Fermi surface has to be studied. In the chapter 3, we therefore investigated a two-band Hubbard model on a square lattice. We introduced the Hamiltonian for two degenerate p{sub x}-p{sub y} (or d{sub xy}-d{sub yz}) orbitals where we considered electron transfers between nearest neighbors and next-nearest neighbors. The orbital degeneracy reduces the number of different hopping parameters but transitions between the two orbitals are still permitted, i.e., the local orbital quantum number is not conserved in the lattice. For two degenerate orbitals, all local Coulomb interactions can be expressed in terms of the Hubbard interaction U and the Hund's-rule coupling J. The Hubbard interaction suppresses charge fluctuations in the lattice, and the Hund's rule coupling tends to maximize the local spin. We incorporated the symmetry constraints in the Gutzwiller variational states. As our first application, we studied the ferromagnetic phase transition as a function of the model parameters for various band fillings. In general, a large density of states and a strong Hund's-rule exchange favor ferromagnetism. In the Gutzwiller wave function, the ferromagnetic order is strongly suppressed so that much larger interaction strength are needed than predicted by the Hartree-Fock solution. Moreover, the regions in parameter space where non-saturated ferromagnetism occurs are much broader in Gutzwiller theory. As shown in earlier

  20. Refraction of Radio Waves on the Radio-Occultation Satellite-to-Satellite Paths as a Characteristic of the Atmospheric State

    Science.gov (United States)

    Matyugov, S. S.; Yakovlev, O. I.; Pavelyev, A. G.; Pavelyev, A. A.; Anufriev, V. A.

    2017-10-01

    We present the results of analyzing the radio-wave refractive characteristics measured on the radio-occultation paths between the GPS navigation satellites and the FORMOSAT-3 research satellites in the central region of the European territory of Russia in 2007-2013. The diurnal, seasonal, and annual variations in the refraction angle at altitudes of 2 to 25 km are discussed. It is shown that the refraction angle can be used as an independent characteristic of the atmospheric state and its long-term variation trends. Diurnal and nocturnal variations in the refraction angle in the winter and summer seasons are analyzed. Trends in the atmospheric refraction variations over seven years are discussed.

  1. SUBMILLIMETER-WAVE ROTATIONAL SPECTROSCOPY OF H2F+

    International Nuclear Information System (INIS)

    Fujimori, R.; Kawaguchi, K.; Amano, T.

    2011-01-01

    Five pure rotational transitions of H 2 F + generated by a discharge in an HF/H 2 /Ar mixture were observed in the range 473-774 GHz with a backward-wave oscillator based submillimeter-wave spectrometer. A simultaneous analysis of the rotational lines with 120 combination differences for the ground state derived from the infrared spectra was carried out to determine the precise molecular constants for the ground state. The rotational transition frequencies that lie below 2 THz were calculated, together with their estimated uncertainties, to facilitate future astronomical identifications. The chemistry for H 2 F + formation in interstellar space is discussed in comparison with a case for recently detected H 2 Cl + .

  2. Lateral variation in crustal and mantle structure in Bay of Bengal based on surface wave data

    Science.gov (United States)

    Kumar, Amit; Mukhopadhyay, Sagarika; Kumar, Naresh; Baidya, P. R.

    2018-01-01

    Surface waves generated by earthquakes that occurred near Sumatra, Andaman-Nicobar Island chain and Sunda arc are used to estimate crustal and upper mantle S wave velocity structure of Bay of Bengal. Records of these seismic events at various stations located along the eastern coast of India and a few stations in the north eastern part of India are selected for such analysis. These stations lie within regional distance of the selected earthquakes. The selected events are shallow focused with magnitude greater than 5.5. Data of 65, 37, 36, 53 and 36 events recorded at Shillong, Bokaro, Visakhapatnam, Chennai and Trivandrum stations respectively are used for this purpose. The ray paths from the earthquake source to the recording stations cover different parts of the Bay of Bengal. Multiple Filtering Technique (MFT) is applied to compute the group velocities of surface waves from the available data. The dispersion curves thus obtained for this data set are within the period range of 15-120 s. Joint inversion of Rayleigh and Love wave group velocity is carried out to obtain the subsurface information in terms of variation of S wave velocity with depth. The estimated S wave velocity at a given depth and layer thickness can be considered to be an average value for the entire path covered by the corresponding ray paths. However, we observe variation in the value of S wave velocity and layer thickness from data recorded at different stations, indicating lateral variation in these two parameters. Thick deposition of sediments is observed along the paths followed by surface waves to Shillong and Bokaro stations. Sediment thickness keeps on decreasing as the surface wave paths move further south. Based on velocity variation the sedimentary layer is further divided in to three parts; on top lay unconsolidated sediment, underlain by consolidated sediment. Below this lies a layer which we consider as meta-sediments. The thickness and velocity of these layers decrease from north

  3. The Electro-Excitation Form Factors for Ground and 5.65 MeV Excited States of 6Li Nucleus

    International Nuclear Information System (INIS)

    Dakhil, Z.A.; Salih, L.; Al-Qazaz, B.S.

    2010-01-01

    The transverse electron scattering form factors are calculated for the ground state and for the (5.65 MeV) excited state [JπT =1 + 2 0 ] of 6 Li. These form factors are analyzed in the framework of the harmonic oscillator shell model. The two-body interaction of Cohen and Kurath is used to generate the p-shell wave functions. The core polarization effects are included in the calculations through effective g-factors. A higher configuration effect outside the 1p-shell model space enhances the form factors for q-values and reasonably reproduces the data. The results are compared with other theoretical models

  4. Theory of ground state factorization in quantum cooperative systems.

    Science.gov (United States)

    Giampaolo, Salvatore M; Adesso, Gerardo; Illuminati, Fabrizio

    2008-05-16

    We introduce a general analytic approach to the study of factorization points and factorized ground states in quantum cooperative systems. The method allows us to determine rigorously the existence, location, and exact form of separable ground states in a large variety of, generally nonexactly solvable, spin models belonging to different universality classes. The theory applies to translationally invariant systems, irrespective of spatial dimensionality, and for spin-spin interactions of arbitrary range.

  5. Basic equations of the quasiparticle-phonon nuclear model with the effects due to the Pauli principle and the phonon ground state correlations

    International Nuclear Information System (INIS)

    Nguyen Dinh Dang; Voronov, V.V.

    1983-01-01

    A system of basic equations of the quasiparticle-phonon model is obtained for energies and a structure of excited states described by the wave functions containing one- and two-phonon components. The effects due to the Pauli principle for two-phonon components and the phonon ground state correlations of a spherical nucleus are taken here into account. The quantitative estimations of these effects are given by a simplified scheme. The relation between these equations with the results from other theoretical approaches is discussed

  6. Antibonding hole ground state in InAs quantum dot molecules

    Energy Technology Data Exchange (ETDEWEB)

    Planelles, Josep [Departament de Química Física i Analítica, Universitat Jaume I, E-12080, Castelló (Spain)

    2015-01-22

    Using four-band k⋅p Hamiltonians, we study how strain and position-dependent effective masses influence hole tunneling in vertically coupled InAs/GaAs quantum dots. Strain reduces the tunneling and hence the critical interdot distance required for the ground state to change from bonding to antibonding. Variable mass has the opposite effect and a rough compensation leaves little affected the critical bonding-to-antibonding ground state crossover. An alternative implementation of the magnetic field in the envelope function Hamiltonian is given which retrieves the experimental denial of possible after growth reversible magnetically induced bonding-to-antibonding ground state transition, predicted by the widely used Luttinger-Kohn Hamiltonian.

  7. Application of Coupled-Wave Wentzel-Kramers-Brillouin Approximation to Ground Penetrating Radar

    OpenAIRE

    Igor Prokopovich; Alexei Popov; Lara Pajewski; Marian Marciniak

    2017-01-01

    This paper deals with bistatic subsurface probing of a horizontally layered dielectric half-space by means of ultra-wideband electromagnetic waves. In particular, the main objective of this work is to present a new method for the solution of the two-dimensional back-scattering problem arising when a pulsed electromagnetic signal impinges on a non-uniform dielectric half-space; this scenario is of interest for ground penetrating radar (GPR) applications. For the analytical description of the s...

  8. A Model Ground State of Polyampholytes

    International Nuclear Information System (INIS)

    Wofling, S.; Kantor, Y.

    1998-01-01

    The ground state of randomly charged polyampholytes (polymers with positive and negatively charged groups along their backbone) is conjectured to have a structure similar to a necklace, made of weakly charged parts of the chain, compacting into globules, connected by highly charged stretched 'strings' attempted to quantify the qualitative necklace model, by suggesting a zero approximation model, in which the longest neutral segment of the polyampholyte forms a globule, while the remaining part will form a tail. Expanding this approximation, we suggest a specific necklace-type structure for the ground state of randomly charged polyampholyte's, where all the neutral parts of the chain compact into globules: The longest neutral segment compacts into a globule; in the remaining part of the chain, the longest neutral segment (the second longest neutral segment) compacts into a globule, then the third, and so on. A random sequence of charges is equivalent to a random walk, and a neutral segment is equivalent to a loop inside the random walk. We use analytical and Monte Carlo methods to investigate the size distribution of loops in a one-dimensional random walk. We show that the length of the nth longest neutral segment in a sequence of N monomers (or equivalently, the nth longest loop in a random walk of N steps) is proportional to N/n 2 , while the mean number of neutral segments increases as √N. The polyampholytes in the ground state within our model is found to have an average linear size proportional to dN, and an average surface area proportional to N 2/3

  9. The magnetic ground state and relationship to Kitaev physics in α-RuCl3

    Science.gov (United States)

    Banerjee, Arnab

    The 2D Kitaev candidate alpha-RuCl3 consists of stacked honeycomb layers weakly coupled by Van der Waals interactions. Here we report the measurements of bulk properties and neutron diffraction in both powder and single crystal samples. Our results show that the full three dimensional magnetic ground state is highly pliable with at least two dominant phases corresponding to two different out-of-plane magnetic orders. They have different Neel temperatures dependent on the stacking of the 2D layers, such as a broad magnetic transition at TN = 14 K as observed in phase-pure powder samples, or a sharp magnetic transition at a lower TN = 7 K as observed in homogeneous single crystals with no evidence for stacking faults. The magnetic refinements of the neutron scattering data will be discussed, which in all cases shows the in-plane magnetic ground state is the zigzag phase common in Kitaev related materials including the honeycomb lattice Iridates. Inelastic neutron scattering in all cases shows that this material consistently exhibit strong two-dimensional magnetic fluctuations leading to a break-down of the classical spin-wave picture. Work performed at ORNL is supported by U.S. Dept. of Energy, Office of Basic Energy Sciences and Office of User Facilities Division.

  10. Three-body problem in the ground-state representation

    International Nuclear Information System (INIS)

    Gonzalez, A.

    1993-01-01

    The ground-state probability density of a three-body system is used to construct a classical potential U whose minimum coincides exactly with the ground-state energy. The spectrum of excited states may approximately be obtained by imposing quasiclassical quantization conditions over the classical motion in U. We show nontrivial one-dimensional models in which either this quantization condition is exact or considerably improves the usual semiclassical quantization. For three-dimensional problems, the small-oscillation frequencies in states with total angular momentum L = 0 are computed. These frequencies could represent an improvement over the frequencies of triatomic molecules computed with the use of ordinary quasiclassics for the motion of the nuclei in the molecular term. By providing a semiclassical description of the first excited quantum states, the sketched approach rises some interesting questions such as, for example, the relevance (once again) of classical chaos to quantum mechanics

  11. Adaptation and innovation: a grounded theory study of procedural variation in the academic surgical workplace.

    Science.gov (United States)

    Apramian, Tavis; Watling, Christopher; Lingard, Lorelei; Cristancho, Sayra

    2015-10-01

    Surgical research struggles to describe the relationship between procedural variations in daily practice and traditional conceptualizations of evidence. The problem has resisted simple solutions, in part, because we lack a solid understanding of how surgeons conceptualize and interact around variation, adaptation, innovation, and evidence in daily practice. This grounded theory study aims to describe the social processes that influence how procedural variation is conceptualized in the surgical workplace. Using the constructivist grounded theory methodology, semi-structured interviews with surgeons (n = 19) from four North American academic centres were collected and analysed. Purposive sampling targeted surgeons with experiential knowledge of the role of variations in the workplace. Theoretical sampling was conducted until a theoretical framework representing key processes was conceptually saturated. Surgical procedural variation was influenced by three key processes. Seeking improvement was shaped by having unsolved procedural problems, adapting in the moment, and pursuing personal opportunities. Orienting self and others to variations consisted of sharing stories of variations with others, taking stock of how a variation promoted personal interests, and placing trust in peers. Acting under cultural and material conditions was characterized by being wary, positioning personal image, showing the logic of a variation, and making use of academic resources to do so. Our findings include social processes that influence how adaptations are incubated in surgical practice and mature into innovations. This study offers a language for conceptualizing the sociocultural influences on procedural variations in surgery. Interventions to change how surgeons interact with variations on a day-to-day basis should consider these social processes in their design. © 2015 John Wiley & Sons, Ltd.

  12. Multi-Band (K- Q- and E-Band) Multi-Tone Millimeter-Wave Frequency Synthesizer for Radio Wave Propagation Studies

    Science.gov (United States)

    Simons, Rainee N.; Wintucky, Edwin G.

    2014-01-01

    This paper presents the design and test results of a multi-band multi-tone millimeter-wave frequency synthesizer, based on a solid-state frequency comb generator. The intended application of the synthesizer is in a space-borne transmitter for radio wave atmospheric studies at K-band (18 to 26.5 GHz), Q-band (37 to 42 GHz), and E-band (71 to 76 GHz). These studies would enable the design of robust multi-Gbps data rate space-to-ground satellite communication links. Lastly, the architecture for a compact multi-tone beacon transmitter, which includes a high frequency synthesizer, a polarizer, and a conical horn antenna, has been investigated for a notional CubeSat based space-to-ground radio wave propagation experiment.

  13. Variation of Time Domain Failure Probabilities of Jack-up with Wave Return Periods

    Science.gov (United States)

    Idris, Ahmad; Harahap, Indra S. H.; Ali, Montassir Osman Ahmed

    2018-04-01

    This study evaluated failure probabilities of jack up units on the framework of time dependent reliability analysis using uncertainty from different sea states representing different return period of the design wave. Surface elevation for each sea state was represented by Karhunen-Loeve expansion method using the eigenfunctions of prolate spheroidal wave functions in order to obtain the wave load. The stochastic wave load was propagated on a simplified jack up model developed in commercial software to obtain the structural response due to the wave loading. Analysis of the stochastic response to determine the failure probability in excessive deck displacement in the framework of time dependent reliability analysis was performed by developing Matlab codes in a personal computer. Results from the study indicated that the failure probability increases with increase in the severity of the sea state representing a longer return period. Although the results obtained are in agreement with the results of a study of similar jack up model using time independent method at higher values of maximum allowable deck displacement, it is in contrast at lower values of the criteria where the study reported that failure probability decreases with increase in the severity of the sea state.

  14. Uniqueness of non-linear ground states for fractional Laplacians in R

    DEFF Research Database (Denmark)

    Frank, Rupert L.; Lenzmann, Enno

    2013-01-01

    We prove uniqueness of ground state solutions Q = Q(|x|) ≥ 0 of the non-linear equation (−Δ)sQ+Q−Qα+1=0inR,where 0 fractional Laplacian in one dimension. In particular, we answer affirmatively an open question...... recently raised by Kenig–Martel–Robbiano and we generalize (by completely different techniques) the specific uniqueness result obtained by Amick and Toland for s=12 and α = 1 in [5] for the Benjamin–Ono equation. As a technical key result in this paper, we show that the associated linearized operator L...... + = (−Δ) s +1−(α+1)Q α is non-degenerate; i.e., its kernel satisfies ker L + = span{Q′}. This result about L + proves a spectral assumption, which plays a central role for the stability of solitary waves and blowup analysis for non-linear dispersive PDEs with fractional Laplacians, such as the generalized...

  15. Stability of quantum-dot excited-state laser emission under simultaneous ground-state perturbation

    Energy Technology Data Exchange (ETDEWEB)

    Kaptan, Y., E-mail: yuecel.kaptan@physik.tu-berlin.de; Herzog, B.; Schöps, O.; Kolarczik, M.; Woggon, U.; Owschimikow, N. [Institut für Optik und Atomare Physik, Technische Universität Berlin, Berlin (Germany); Röhm, A.; Lingnau, B.; Lüdge, K. [Institut für Theoretische Physik, Technische Universität Berlin, Berlin (Germany); Schmeckebier, H.; Arsenijević, D.; Bimberg, D. [Institut für Festkörperphysik, Technische Universität Berlin, Berlin (Germany); Mikhelashvili, V.; Eisenstein, G. [Technion Institute of Technology, Faculty of Electrical Engineering, Haifa (Israel)

    2014-11-10

    The impact of ground state amplification on the laser emission of In(Ga)As quantum dot excited state lasers is studied in time-resolved experiments. We find that a depopulation of the quantum dot ground state is followed by a drop in excited state lasing intensity. The magnitude of the drop is strongly dependent on the wavelength of the depletion pulse and the applied injection current. Numerical simulations based on laser rate equations reproduce the experimental results and explain the wavelength dependence by the different dynamics in lasing and non-lasing sub-ensembles within the inhomogeneously broadened quantum dots. At high injection levels, the observed response even upon perturbation of the lasing sub-ensemble is small and followed by a fast recovery, thus supporting the capacity of fast modulation in dual-state devices.

  16. Flapping current sheet with superposed waves seen in space and on the ground

    Science.gov (United States)

    Wang, Guoqiang; Volwerk, Martin; Nakamura, Rumi; Boakes, Peter; Zhang, Tielong; Ge, Yasong; Yoshikawa, Akimasa; Baishev, Dmitry

    2015-04-01

    A wavy current sheet event observed on 15th of October 2004 between 1235 and 1300 UT has been studied by using Cluster and ground-based magnetometer data. Waves propagating from the tail centre to the duskside flank with a period ~30 s and wavelength ~1 RE, are superimposed on a flapping current sheet, accompanied with a bursty bulk flow (BBF). Three Pi2 pulsations, with onset at ~1236, ~1251 and ~1255 UT, respectively, are observed at the Tixie (TIK) station located near the foot-points of Cluster. The mechanism creating the Pi2 (period ~40 s) onset at ~1236 UT is unclear. The second Pi2 (period ~90 s, onset at ~1251 UT) is associated with a strong field-aligned current, which has a strong transverse component of the magnetic field, observed by Cluster with a time delay ~60 s. We suggest that it is caused by bouncing Alfvén waves between the northern and southern ionosphere which transport the field-aligned current. For the third Pi2 (period ~60 s) there is almost no damping at the first three periods. They occur in conjunction with periodic field-aligned currents one-on-one with 72s delay. We suggest that it is generated by these periodic field-aligned currents. We conclude that the strong field-aligned currents generated in the plasma sheet during flapping with superimposed higher frequency waves can drive Pi2 pulsations on the ground, and periodic field-aligned currents can even control the period of the Pi2s.

  17. Variational Monte Carlo Method with Dirichlet Boundary Conditions: Application to the Study of Confined Systems by Impenetrable Surfaces with Different Symmetries.

    Science.gov (United States)

    Sarsa, Antonio; Le Sech, Claude

    2011-09-13

    Variational Monte Carlo method is a powerful tool to determine approximate wave functions of atoms, molecules, and solids up to relatively large systems. In the present work, we extend the variational Monte Carlo approach to study confined systems. Important properties of the atoms, such as the spatial distribution of the electronic charge, the energy levels, or the filling of electronic shells, are modified under confinement. An expression of the energy very similar to the estimator used for free systems is derived. This opens the possibility to study confined systems with little changes in the solution of the corresponding free systems. This is illustrated by the study of helium atom in its ground state (1)S and the first (3)S excited state confined by spherical, cylindrical, and plane impenetrable surfaces. The average interelectronic distances are also calculated. They decrease in general when the confinement is stronger; however, it is seen that they present a minimum for excited states under confinement by open surfaces (cylindrical, planes) around the radii values corresponding to ionization. The ground (2)S and the first (2)P and (2)D excited states of the lithium atom are calculated under spherical constraints for different confinement radii. A crossing between the (2)S and (2)P states is observed around rc = 3 atomic units, illustrating the modification of the atomic energy level under confinement. Finally the carbon atom is studied in the spherical symmetry by using both variational and diffusion Monte Carlo methods. It is shown that the hybridized state sp(3) becomes lower in energy than the ground state (3)P due to a modification and a mixing of the atomic orbitals s, p under strong confinement. This result suggests a model, at least of pedagogical interest, to interpret the basic properties of carbon atom in chemistry.

  18. ULF wave effects on high frequency signal propagation through the ionosphere

    Directory of Open Access Journals (Sweden)

    C. L. Waters

    2009-07-01

    Full Text Available Variations in the total electron content (TEC of the ionosphere alter the propagation characteristics of EM radiation for frequencies above a few megahertz (MHz. Spatial and temporal variations of the ionosphere TEC influence highly sensitive, ground based spatial measurements such as those used in radio astronomy and Global Positioning System (GPS applications. In this paper we estimate the magnitudes of the changes in TEC and the time delays of high frequency signals introduced by variations in the ionosphere electron density caused by the natural spectrum of ultra-low frequency (ULF wave activity that originates in near-Earth space. The time delays and associated phase shifts depend on the frequency, spatial structure and amplitude of the ULF waves.

  19. On calculations of the ground state energy in quantum mechanics

    International Nuclear Information System (INIS)

    Efimov, G.V.

    1991-02-01

    In nonrelativistic quantum mechanics the Wick-ordering method called the oscillator representation suggested to calculate the ground-state energy for a wide class of potentials allowing the existence of a bound state. The following examples are considered: the orbital excitations of the ground-state in the Coulomb plus linear potential, the Schroedinger equation with a ''relativistic'' kinetic energy √p 2 +m 2 , the Coulomb three-body problem. (author). 22 refs, 2 tabs

  20. Ground-state structures of Hafnium clusters

    Energy Technology Data Exchange (ETDEWEB)

    Ng, Wei Chun; Yoon, Tiem Leong [School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Lim, Thong Leng [Faculty of Engineering and Technoloty, Multimedia University, Melaca Campus, 75450 Melaka (Malaysia)

    2015-04-24

    Hafnium (Hf) is a very large tetra-valence d-block element which is able to form relatively long covalent bond. Researchers are interested to search for substitution to silicon in the semi-conductor industry. We attempt to obtain the ground-state structures of small Hf clusters at both empirical and density-functional theory (DFT) levels. For calculations at the empirical level, charge-optimized many-body functional potential (COMB) is used. The lowest-energy structures are obtained via a novel global-minimum search algorithm known as parallel tempering Monte-Carlo Basin-Hopping and Genetic Algorithm (PTMBHGA). The virtue of using COMB potential for Hf cluster calculation lies in the fact that by including the charge optimization at the valence shells, we can encourage the formation of proper bond hybridization, and thus getting the correct bond order. The obtained structures are further optimized using DFT to ensure a close proximity to the ground-state.

  1. Probing quantum frustrated systems via factorization of the ground state.

    Science.gov (United States)

    Giampaolo, Salvatore M; Adesso, Gerardo; Illuminati, Fabrizio

    2010-05-21

    The existence of definite orders in frustrated quantum systems is related rigorously to the occurrence of fully factorized ground states below a threshold value of the frustration. Ground-state separability thus provides a natural measure of frustration: strongly frustrated systems are those that cannot accommodate for classical-like solutions. The exact form of the factorized ground states and the critical frustration are determined for various classes of nonexactly solvable spin models with different spatial ranges of the interactions. For weak frustration, the existence of disentangling transitions determines the range of applicability of mean-field descriptions in biological and physical problems such as stochastic gene expression and the stability of long-period modulated structures.

  2. Effects of temperature variations on guided waves propagating in composite structures

    Science.gov (United States)

    Shoja, Siavash; Berbyuk, Viktor; Boström, Anders

    2016-04-01

    Effects of temperature on guided waves propagating in composite materials is a well-known problem which has been investigated in many studies. The majority of the studies is focused on effects of high temperature. Understanding the effects of low temperature has major importance in composite structures and components which are operating in cold climate conditions such as e.g. wind turbines operating in cold climate regions. In this study first the effects of temperature variations on guided waves propagating in a composite plate is investigated experimentally in a cold climate chamber. The material is a common material used to manufacture rotor blades of wind turbines. The temperature range is 25°C to -25°C and effects of temperature variations on amplitude and phase shift of the received signal are investigated. In order to apply the effects of lowering the temperature on the received signal, the Baseline Signal Stretch (BSS) method is modified and used. The modification is based on decomposing the signal into symmetric and asymmetric modes and applying two different stretch factors on each of them. Finally the results obtained based on the new method is compared with the results of application of BSS with one stretch factor and experimental measurements. Comparisons show that an improvement is obtained using the BSS with the mode decomposition method at temperature variations of more than 25°C.

  3. Ground state properties of neutron-rich Mg isotopes the "island of inversion" studied with laser and $\\beta$-NMR spectroscopy

    CERN Document Server

    Kowalska, M

    2006-01-01

    Studies in regions of the nuclear chart in which the model predictions of properties of nuclei fail can bring a better understanding of the strong interaction in the nuclear medium. To such regions belongs the so called "island of inversion" centered around Ne, Na and Mg isotopes with 20 neutrons in which unexpected ground-state spins, large deformations and dense low-energy spectra appear. This is a strong argument that the magic N=20 is not a closed shell in this area. In this thesis investigations of isotope shifts of stable $^{24-26}$Mg, as well as spins and magnetic moments of short-lived $^{29,31}$Mg are presented. The successful studies were performed at the ISOLDE facility at CERN using collinear laser and $\\beta$-NMR spectroscopy techniques. The isotopes were investigated as single-charged ions in the 280 nm transition from the atomic ground state $^2\\!$S$_{1/2}$ to one of the two lowest excited states $^2\\!$P$_{1/2 ,\\,3/2}$ using continuous wave laser beams. The isotope-shift measurements with fluor...

  4. Antiferrodistortive phase transitions and ground state of PZT ceramics

    International Nuclear Information System (INIS)

    Pandey, Dhananjai

    2013-01-01

    The ground state of the technologically important Pb(Zr x Ti (1-x) )O 3 , commonly known as PZT, ceramics is currently under intense debate. The phase diagram of this material shows a morphotropic phase boundary (MPB) for x∼0.52 at 300K, across which a composition induced structural phase transition occurs leading to maximization of the piezoelectric properties. In search for the true ground state of the PZT in the MPB region, Beatrix Noheda and coworkers first discovered a phase transition from tetragonal (space group P4mm) to an M A type monoclinic phase (space group Cm) at low temperatures for x=0.52. Soon afterwards, we discovered yet another low temperature phase transition for the same composition in which the M A type (Cm) monoclinic phase transforms to another monoclinic phase with Cc space group. We have shown that the Cm to Cc phase transition is an antiferrodistortive (AFD) transition involving tilting of oxygen octahedra leading to unit cell doubling and causing appearance of superlattice reflections which are observable in the electron and neutron diffraction patterns only and not in the XRD patterns, as a result of which Noheda and coworkers missed the Cc phase in their synchrotron XRD studies at low temperatures. Our findings were confirmed by leading groups using neutron, TEM, Raman and high pressure diffraction studies. The first principles calculations also confirmed that the true ground state of PZT in the MPB region has Cc space group. However, in the last couple of years, the Cc space group of the ground state has become controversial with an alternative proposal of R3c as the space group of the ground state phase which is proposed to coexist with the metastable Cm phase. In order to resolve this controversy, we recently revisited the issue using pure PZT and 6% Sr 2+ substituted PZT, the latter samples show larger tilt angle on account of the reduction in the average cationic radius at the Pb 2+ site. Using high wavelength neutrons and high

  5. Variation in Differential and Total Cross Sections Due to Different Radial Wave Functions

    Science.gov (United States)

    Williamson, W., Jr.; Greene, T.

    1976-01-01

    Three sets of analytical wave functions are used to calculate the Na (3s---3p) transition differential and total electron excitation cross sections by Born approximations. Results show expected large variations in values. (Author/CP)

  6. Ground state correlations and structure of odd spherical nuclei

    International Nuclear Information System (INIS)

    Mishev, S.; Voronov, V. V.

    2006-01-01

    It is well known that the Pauli principle plays a substantial role at low energies because the phonon operators are not ideal boson operators. Calculating the exact commutators between the quasiparticle and phonon operators one can take into account the Pauli principle corrections. Besides the ground state correlations due to the quasiparticle interaction in the ground state influence the single particle fragmentation as well. In this paper, we generalize the basic QPM equations to account for both mentioned effects. As an illustration of our approach, calculations on the structure of the low-lying states in "1"3"1Ba have been performed.

  7. VLF wave injections from the ground

    Science.gov (United States)

    Helliwell, R. A.

    1983-01-01

    Experiments on wave-particle interactions using VLF whistler-mode waves injected into the magnetosphere from Antartica are described. The injected signals are single-frequency coherent waves whose amplitudes and frequencies may be changed slowly with time, or else two or more coherent wave trains transmitted simultaneously to determine the nature of the response to multifrequency excitation. The waves may be amplified 30 dB or more and may trigger intense emissions having bandwidths that vary from a few to several hundred Hertz. In most cases significant growth and triggering occur only when the driving signal is essentially monochromatic (bandwidth 10 Hz). If two frequencies are transmitted simultaneously the signal at the lower frequency tends to be suppressed by 20 dB or more. These results are interpreted in terms of a feedback interaction between the waves and counter-streaming cyclotron resonant electrons in a region several hundred wavelengths long, centered on the magnetic equator.

  8. Coexisting Kondo singlet state with antiferromagnetic long-range order: A possible ground state for Kondo insulators

    International Nuclear Information System (INIS)

    Zhang Guangming; Yu Lu

    2000-04-01

    The ground-state phase diagram of a half-filled anisotropic Kondo lattice model is calculated within a mean-field theory. For small transverse exchange coupling J perpendicular perpendicular c1 , the ground state shows an antiferromagnetic long-range order with finite staggered magnetizations of both localized spins and conduction electrons. When J perpendicular > J perpendicular c2 , the long-range order is destroyed and the system is in a disordered Kondo singlet state with a hybridization gap. Both ground states can describe the low-temperature phases of Kondo insulating compounds. Between these two distinct phases, there may be a coexistent regime as a result of the balance between local Kondo screening and magnetic interactions. (author)

  9. Spin waves in terbium. III. Magnetic anisotropy at zero wave vector

    DEFF Research Database (Denmark)

    Houmann, Jens Christian Gylden; Jensen, J.; Touborg, P.

    1975-01-01

    The energy gap at zero wave vector in the spin-wave dispersion relation of ferromagnetic. Tb has been studied by inelastic neutron scattering. The energy was measured as a function of temperature and applied magnetic field, and the dynamic anisotropy parameters were deduced from the results...... the effects of zero-point deviations from the fully aligned ground state, and we tentatively propose polarization-dependent two-ion couplings as their origin........ The axial anisotropy is found to depend sensitively on the orientation of the magnetic moments in the basal plane. This behavior is shown to be a convincing indication of considerable two-ion contributions to the magnetic anisotropy at zero wave vector. With the exception of the sixfold basal...

  10. Modeling per capita state health expenditure variation: state-level characteristics matter.

    Science.gov (United States)

    Cuckler, Gigi; Sisko, Andrea

    2013-01-01

    In this paper, we describe the methods underlying the econometric model developed by the Office of the Actuary in the Centers for Medicare & Medicaid Services, to explain differences in per capita total personal health care spending by state, as described in Cuckler, et al. (2011). Additionally, we discuss many alternative model specifications to provide additional insights for valid interpretation of the model. We study per capita personal health care spending as measured by the State Health Expenditures, by State of Residence for 1991-2009, produced by the Centers for Medicare & Medicaid Services' Office of the Actuary. State-level demographic, health status, economic, and health economy characteristics were gathered from a variety of U.S. government sources, such as the Census Bureau, Bureau of Economic Analysis, the Centers for Disease Control, the American Hospital Association, and HealthLeaders-InterStudy. State-specific factors, such as income, health care capacity, and the share of elderly residents, are important factors in explaining the level of per capita personal health care spending variation among states over time. However, the slow-moving nature of health spending per capita and close relationships among state-level factors create inefficiencies in modeling this variation, likely resulting in incorrectly estimated standard errors. In addition, we find that both pooled and fixed effects models primarily capture cross-sectional variation rather than period-specific variation.

  11. Semileptonic decays of B_c meson to S-wave charmonium states in the perturbative QCD approach

    International Nuclear Information System (INIS)

    Rui, Zhou; Li, Hong; Wang, Guang-xin; Xiao, Ying

    2016-01-01

    Inspired by the recent measurement of the ratio of B_c branching fractions to J/ψπ"+ and J/ψμ"+ν_μ final states at the LHCb detector, we study the semileptonic decays of B_c meson to the S-wave ground and radially excited 2S and 3S charmonium states with the perturbative QCD approach. After evaluating the form factors for the transitions B_c → P,V, where P and V denote pseudoscalar and vector S-wave charmonia, respectively, we calculate the branching ratios for all these semileptonic decays. The theoretical uncertainty of hadronic input parameters are reduced by utilizing the light-cone wave function for the B_c meson. It is found that the predicted branching ratios range from 10"-"7 up to 10"-"2 and could be measured by the future LHCb experiment. Our prediction for the ratio of branching fractions (BR(B_c"+→J/Ψπ"+))/(BR(B_c"+→J/Ψμ"+ν_μ)) is in good agreement with the data. For B_c → Vlν_l decays, the relative contributions of the longitudinal and transverse polarization are discussed in different momentum transfer squared regions. These predictions will be tested on the ongoing and forthcoming experiments. (orig.)

  12. Rearrangements in ground and excited states

    CERN Document Server

    de Mayo, Paul

    1980-01-01

    Rearrangements in Ground and Excited States, Volume 3 presents essays on the chemical generation of excited states; the cis-trans isomerization of olefins; and the photochemical rearrangements in trienes. The book also includes essays on the zimmerman rearrangements; the photochemical rearrangements of enones; the photochemical rearrangements of conjugated cyclic dienones; and the rearrangements of the benzene ring. Essays on the photo rearrangements via biradicals of simple carbonyl compounds; the photochemical rearrangements involving three-membered rings or five-membered ring heterocycles;

  13. Effects of the magnetic field variation on the spin wave interference in a magnetic cross junction

    Science.gov (United States)

    Balynskiy, M.; Chiang, H.; Kozhevnikov, A.; Dudko, G.; Filimonov, Y.; Balandin, A. A.; Khitun, A.

    2018-05-01

    This article reports results of the investigation of the effect of the external magnetic field variation on the spin wave interference in a magnetic cross junction. The experiments were performed using a micrometer scale Y3Fe5O12 cross structure with a set of micro-antennas fabricated on the edges of the cross arms. Two of the antennas were used for the spin wave excitation while a third antenna was used for detecting the inductive voltage produced by the interfering spin waves. It was found that a small variation of the bias magnetic field may result in a significant change of the output inductive voltage. The effect is most prominent under the destructive interference condition. The maximum response exceeds 30 dB per 0.1 Oe at room temperature. It takes a relatively small bias magnetic field variation of about 1 Oe to drive the system from the destructive to the constructive interference conditions. The switching is accompanied by a significant, up to 50 dB, change in the output voltage. The obtained results demonstrate a feasibility of the efficient spin wave interference control by an external magnetic field, which may be utilized for engineering novel type of magnetometers and magnonic logic devices.

  14. Extensive Variation in Chromatin States Across Humans

    KAUST Repository

    Kasowski, M.

    2013-10-17

    The majority of disease-associated variants lie outside protein-coding regions, suggesting a link between variation in regulatory regions and disease predisposition. We studied differences in chromatin states using five histone modifications, cohesin, and CTCF in lymphoblastoid lines from 19 individuals of diverse ancestry. We found extensive signal variation in regulatory regions, which often switch between active and repressed states across individuals. Enhancer activity is particularly diverse among individuals, whereas gene expression remains relatively stable. Chromatin variability shows genetic inheritance in trios, correlates with genetic variation and population divergence, and is associated with disruptions of transcription factor binding motifs. Overall, our results provide insights into chromatin variation among humans.

  15. Extensive Variation in Chromatin States Across Humans

    KAUST Repository

    Kasowski, M.; Kyriazopoulou-Panagiotopoulou, S.; Grubert, F.; Zaugg, J. B.; Kundaje, A.; Liu, Y.; Boyle, A. P.; Zhang, Q. C.; Zakharia, F.; Spacek, D. V.; Li, J.; Xie, D.; Olarerin-George, A.; Steinmetz, L. M.; Hogenesch, J. B.; Kellis, M.; Batzoglou, S.; Snyder, M.

    2013-01-01

    The majority of disease-associated variants lie outside protein-coding regions, suggesting a link between variation in regulatory regions and disease predisposition. We studied differences in chromatin states using five histone modifications, cohesin, and CTCF in lymphoblastoid lines from 19 individuals of diverse ancestry. We found extensive signal variation in regulatory regions, which often switch between active and repressed states across individuals. Enhancer activity is particularly diverse among individuals, whereas gene expression remains relatively stable. Chromatin variability shows genetic inheritance in trios, correlates with genetic variation and population divergence, and is associated with disruptions of transcription factor binding motifs. Overall, our results provide insights into chromatin variation among humans.

  16. Combined effects of traveling seismic waves and soil nonlinearity on nuclear power plant response

    International Nuclear Information System (INIS)

    Lee, T.H.; Charman, C.M.

    1981-01-01

    The effects of ground motion nonuniformity on the seismic input have been actively studied in recent years by considering the passage of traveling seismic waves. These studies gave rise to a new class of soil-structure interaction problems in which the seismic input is modified as a result of the spatial variations of ground motion. The phenomena were usually studied by using the elastic half-space simulation or discrete spring-models for modeling the soil medium. Finite element methods were also used recently on a limited scope. Results obtained from these investigations are often manifested by an attenuation of translational excitation along with an addition of rotational ground motion input. The decrease in structural response resulting from the input loss in the translational component was often insignificant since the response reduction tends to be offset by the effects from rotational input. The traveling wave effects have, so far, been investigated within the framework of linear theory with soil nonlinearity ignored. Conversely, the incorporation of soil nonlinearity in soil-structure interaction analyses has been done without including wave effect. Seismic analyses considering the hysteretic behavior of soil have been performed using highly idealized models for steady-state solution. More elaborate nonlinear seismic models deal with only the strain-dependent soil modulus rather than the transient unloading-reloading type of hysteretic characteristics of soil under a time-function input of earthquake trace. Apparently, the traveling wave effect and soil nonlinearity have been separately treated in the past. The purpose of this paper is to demonstrate that these two major effects can be combined in one model such that the influence of wave passage is reflected through the hysteretic behavior of soil particles, and thereby achieving significant reduction in seismic loads. (orig./RW)

  17. Sharper criteria for the wave collapse

    DEFF Research Database (Denmark)

    Kuznetsov, E.A.; Juul Rasmussen, J.; Rypdal, K.

    1995-01-01

    Sharper criteria for three-dimensional wave collapse described by the Nonlinear Schrodinger Equation (NLSE) are derived. The collapse threshold corresponds to the ground state soliton which is known to be unstable. Thus, for nonprefocusing distributions this represents the separatrix between...

  18. Ionospheric Bow Wave Induced by the Moon Shadow Ship Over the Continent of United States on 21 August 2017

    Science.gov (United States)

    Sun, Yang-Yi; Liu, Jann-Yenq; Lin, Charles Chien-Hung; Lin, Chi-Yen; Shen, Ming-Hsueh; Chen, Chieh-Hung; Chen, Chia-Hung; Chou, Min-Yang

    2018-01-01

    A moon shadow of the total solar eclipse swept through the continent of United States (CONUS) from west to east on 21 August 2017. Massive total electron content (integration of electron density from 0 km to 20,200 km altitude) observations from 2,255 ground-based Global Navigation Satellite System receivers show that the moon shadow ship generates a great ionospheric bow wave front which extends 1,500 km away from the totality path covering the entire CONUS. The bow wave front consists of the acoustic shock wave due to the supersonic/near-supersonic moon shadow ship and the significant plasma recombination due to the reduction in solar irradiation within the shadow area. The deep bow wave trough (-0.02 total electron content unit (1 TECU = 1016 el m-2) area) nearly coincides with the 100% obscuration moving along the totality path over the CONUS through the entire eclipse period. The supersonic moon shadow ship induces a bow wave crest in front of the ship ( 80% obscuration). It is the first time to find the acoustic shock wave-formed bow wave trough and crest near the totality.

  19. The ultraviolet variations of iota Cas

    Science.gov (United States)

    Molnar, M. R.; Mallama, A. D.; Soskey, D. G.; Holm, A. V.

    1976-01-01

    The Ap variable star iota Cas was observed with the photometers on OAO-2 covering the spectral range 1430-4250 A. The ultraviolet light curves show a double wave with primary minimum and maximum at phase ? 0.00 and 0.35, respectively. Secondary minimum light is at phase ? 0.65 with secondary maximum at phase ? 0.85. The light curves longward of 3150 A vary in opposition to those shortward of this 'null region'. Ground-based coude spectra show that the Fe II and Cr II line strengths have a double-wave variation such that maximum strength occurs at minimum ultraviolet light. We suggest that the strong ultraviolet opacities due to photoionization and line blanketing by these metals may cause the observed photometric variations. We have also constructed an oblique-rotator model which shows iron and chromium lying in a great circle band rather than in circular spots.

  20. Method of distinction of pure d-wave state from the mixed state in HTSC

    International Nuclear Information System (INIS)

    Filatova, Tatiana; Brusov, Peter; Brusov, Pavel; Lee, Chong; Chaudhury, Ranjan

    2009-01-01

    Direct observation of the collective modes in unconventional superconductors (USC) by microwave impedance technique experiments has made the study of the collective excitations in these systems very important. One remaining question is the exact form of the order parameter of unconventional superconductors. Extended s-wave pairing, mixture of s- and d-states, as well as of different d-wave states are among possibilities. We have considered the mixtures of d x 2 - y 2 and d xy states in high temperature superconductors (HTSC) and have, for the first time, derived the full set of equations for the collective mode spectrum in the mixed d-wave state with an arbitrary admixture of d xy state. The results we have obtained will allow us to calculate the whole collective mode spectrum, which may then be used for interpretation of sound attenuation and microwave absorption data as well as for identification of the type of pairing and order parameter in unconventional superconductors. In particular, this will allow one to estimate the extent of admixture of d xy state in the possible mixed state.

  1. State estimation for wave energy converters

    Energy Technology Data Exchange (ETDEWEB)

    Bacelli, Giorgio; Coe, Ryan Geoffrey

    2017-04-01

    This report gives a brief discussion and examples on the topic of state estimation for wave energy converters (WECs). These methods are intended for use to enable real-time closed loop control of WECs.

  2. Positive ground state solutions to Schrodinger-Poisson systems with a negative non-local term

    Directory of Open Access Journals (Sweden)

    Yan-Ping Gao

    2015-04-01

    Full Text Available In this article, we study the Schrodinger-Poisson system $$\\displaylines{ -\\Delta u+u-\\lambda K(x\\phi(xu=a(x|u|^{p-1}u, \\quad x\\in\\mathbb{R}^3, \\cr -\\Delta\\phi=K(xu^{2},\\quad x\\in\\mathbb{R}^3, }$$ with $p\\in(1,5$. Assume that $a:\\mathbb{R}^3\\to \\mathbb{R^{+}}$ and $K:\\mathbb{R}^3\\to \\mathbb{R^{+}}$ are nonnegative functions and satisfy suitable assumptions, but not requiring any symmetry property on them, we prove the existence of a positive ground state solution resolved by the variational methods.

  3. Variation in radon exhalation from the ground on the active fault in Kobe

    Energy Technology Data Exchange (ETDEWEB)

    Yasuoka, Y.; Shinogi, M. [Kobe Pharmaceutical Univ., Kobe, Hyogo (Japan)

    1998-12-31

    Since 27 January 1997, the measurements of radon (Rn-222) exhaled from the ground have been made continuously by the use of PICO-RAD detector (Packard instrument Co.) at monitoring stations on Ashiya active fault. The fault may have been slipped by the Kobe earthquake (magnitude 7.2, 17 January 1995). The variation of relative radon exhalation on the fault was large. We guessed the large variation of relative radon exhalation on the fault was caused by not only the influence of meteorology but also the influence of other factors. (author)

  4. Ground state correlations and structure of odd spherical nuclei

    International Nuclear Information System (INIS)

    Mishev, S.; Voronov, V.V.

    2008-01-01

    It is well known that the Pauli principle plays a substantial role at low energies because the phonon operators are not ideal boson operators. Calculating the exact commutators between the quasiparticle and phonon operators one can take into account the Pauli principle corrections. Besides, the ground state correlations due to the quasiparticle interaction in the ground state influence the single-particle fragmentation as well. In this paper, we generalize the basic equations of the quasiparticle-phonon nuclear model to account for both effects mentioned. As an illustration of our approach, calculations on the structure of the low-lying states in 133 Ba have been performed

  5. Variational Monte Carlo Technique

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 19; Issue 8. Variational Monte Carlo Technique: Ground State Energies of Quantum Mechanical Systems. Sukanta Deb. General Article Volume 19 Issue 8 August 2014 pp 713-739 ...

  6. Ground state of the parallel double quantum dot system.

    Science.gov (United States)

    Zitko, Rok; Mravlje, Jernej; Haule, Kristjan

    2012-02-10

    We resolve the controversy regarding the ground state of the parallel double quantum dot system near half filling. The numerical renormalization group predicts an underscreened Kondo state with residual spin-1/2 magnetic moment, ln2 residual impurity entropy, and unitary conductance, while the Bethe ansatz solution predicts a fully screened impurity, regular Fermi-liquid ground state, and zero conductance. We calculate the impurity entropy of the system as a function of the temperature using the hybridization-expansion continuous-time quantum Monte Carlo technique, which is a numerically exact stochastic method, and find excellent agreement with the numerical renormalization group results. We show that the origin of the unconventional behavior in this model is the odd-symmetry "dark state" on the dots.

  7. Explosion source strong ground motions in the Mississippi embayment

    Science.gov (United States)

    Langston, C.A.; Bodin, P.; Powell, C.; Withers, M.; Horton, S.; Mooney, W.

    2006-01-01

    Two strong-motion arrays were deployed for the October 2002 Embayment Seismic Excitation Experiment to study the spatial variation of strong ground motions in the deep, unconsolidated sediments of the Mississippi embayment because there are no comparable strong-motion data from natural earthquakes in the area. Each linear array consisted of eight three-component K2 accelerographs spaced 15 m apart situated 1.2 and 2.5 kin from 2268-kg and 1134-kg borehole explosion sources, respectively. The array data show distinct body-wave and surface-wave arrivals that propagate within the thick, unconsolidated sedimentary column, the high-velocity basement rocks, and small-scale structure near the surface. Time-domain coherence of body-wave and surface-wave arrivals is computed for acceleration, velocity, and displacement time windows. Coherence is high for relatively low-frequency verticalcomponent Rayleigh waves and high-frequency P waves propagating across the array. Prominent high-frequency PS conversions seen on radial components, a proxy for the direct S wave from earthquake sources, lose coherence quickly over the 105-m length of the array. Transverse component signals are least coherent for any ground motion and appear to be highly scattered. Horizontal phase velocity is computed by using the ratio of particle velocity to estimates of the strain based on a plane-wave-propagation model. The resulting time-dependent phase-velocity map is a useful way to infer the propagation mechanisms of individual seismic phases and time windows of three-component waveforms. Displacement gradient analysis is a complementary technique for processing general spatial-array data to obtain horizontal slowness information.

  8. Family, state, class and solidarity: re-conceptualising intergenerational solidarity through the grounded theory approach.

    Science.gov (United States)

    Timonen, Virpi; Conlon, Catherine; Scharf, Thomas; Carney, Gemma

    2013-09-01

    The relationship between class and intergenerational solidarities in the public and private spheres calls for further conceptual and theoretical development. This article discusses the findings from the first wave of a qualitative longitudinal study entitled Changing Generations , conducted in Ireland in 2011-2012, comprising 100 in-depth interviews with men and women across the age and socioeconomic spectrums. Constructivist grounded theory analysis of the data gives rise to the following postulates: (1) intergenerational solidarity at the family level is strongly contoured by socioeconomic status (SES); (2) intergenerational solidarity evolves as family generations observe each others' practices and adjust their expectations accordingly; (3) intergenerational solidarity within families is also shaped by the public sphere (the welfare state) that generates varying expectations and levels of solidarity regarding State supports for different age groups, again largely dependent on SES; (4) the liberal welfare state context, especially at a time of economic crisis, enhances the significance of intergenerational solidarity within families. We conclude by calling for research that is attuned to age/generation, gender and class, and how these operate across the family and societal levels.

  9. Emergence of advance waves in a steady-state universe

    Energy Technology Data Exchange (ETDEWEB)

    Hobart, R.H.

    1979-10-01

    In standard Wheeler-Feynman electrodynamics advanced waves from any source are absolutely canceled by the advanced waves from the absorber responding to that source. The present work shows this cancellation fails over cosmic distances in a steady-state universe. A test of the view proposed earlier, in a paper which assumed failure of cancellation ad hoc, that zero-point fluctuations of the electromagnetic field are such emergent advanced waves, is posed. The view entails anomalous slowing of spontaneous transition rates at longer emission wavelengths; available data go against this, furnishing additional argument against the suspect assumption that the universe is steady-state.

  10. Observation of moving wave packets reveals their quantum state

    International Nuclear Information System (INIS)

    Leonhardt, U.; Raymer, M.G.

    1996-01-01

    We show how to infer the quantum state of a wave packet from position probability distributions measured during the packet close-quote s motion in an arbitrary potential. We assume a nonrelativistic one-dimensional or radial wave packet. Temporal Fourier transformation and spatial sampling with respect to a newly found set of functions project the density-matrix elements out of the probability distributions. The sampling functions are derivatives of products of regular and irregular wave functions. We note that the ability to infer quantum states in this way depends on the structure of the Schroedinger equation. copyright 1996 The American Physical Society

  11. Emergence of advance waves in a steady-state universe

    International Nuclear Information System (INIS)

    Hobart, R.H.

    1979-01-01

    In standard Wheeler-Feynman electrodynamics advanced waves from any source are absolutely canceled by the advanced waves from the absorber responding to that source. The present work shows this cancellation fails over cosmic distances in a steady-state universe. A test of the view proposed earlier, in a paper which assumed failure of cancellation ad hoc, that zero-point fluctuations of the electromagnetic field are such emergent advanced waves, is posed. The view entails anomalous slowing of spontaneous transition rates at longer emission wavelengths; available data go against this, furnishing additional argument against the suspect assumption that the universe is steady-state

  12. RPA ground state correlations in nuclei

    International Nuclear Information System (INIS)

    Lenske, H.

    1990-01-01

    Overcounting in the RPA theory of ground state correlations is shown to be avoided if exact rather than quasiboson commutators are used. Single particle occupation probabilities are formulated in a compact way by the RPA Green function. Calculations with large configuration spaces and realistic interactions are performed with 1p1h RPA and second RPA (SRPA) including 2p2h mixing in excited states. In 41 Ca valence hole states are found to be quenched by about 10% in RPA and up to 18% in SRPA. Contributions from low and high lying excitations and their relation to long and short range correlations in finite nuclei are investigated. (orig.)

  13. Terrestrial propagation of long electromagnetic waves

    CERN Document Server

    Galejs, Janis; Fock, V A

    2013-01-01

    Terrestrial Propagation of Long Electromagnetic Waves deals with the propagation of long electromagnetic waves confined principally to the shell between the earth and the ionosphere, known as the terrestrial waveguide. The discussion is limited to steady-state solutions in a waveguide that is uniform in the direction of propagation. Wave propagation is characterized almost exclusively by mode theory. The mathematics are developed only for sources at the ground surface or within the waveguide, including artificial sources as well as lightning discharges. This volume is comprised of nine chapte

  14. Ion cyclotron waves: Direct compariosn between ground-based measurements and observations in the source region

    International Nuclear Information System (INIS)

    Perraut, S.; Gendrin, R.; Roux, A.; de Villedary, C.

    1984-01-01

    Simultaneous measurements of ion cyclotron waves (ICW's) were performed on GEOS spacecraft and in the vicinity of their magnetic footprints with the French Mobile station. The detailed comparison between the two sets of data shown that while ICW's having F + gyrofrequency at the equator, generally propagate to the ground, only 50% of those generated above F/sub He/ can reach the ground station. It is shown that these results are in good agreement with the conclusions that Rauch and Roux [1982] drew on the basis of measurements reported by Young et al 1981]. In an He + -rich plasma, ICW's with F>F/sub He/ suffer a reflection where the frequency locally matches the local bi-ion hybrid frequency. We extend the calculations of Rauch and Roux and calculate, as a function of the He + concentration, the tunneling of ICW's through the stopband induced by the presence of minor He + ions. It is shown that the transmission coefficient strongly depends upon the wave frequency for a given He + abundance ratio. The results obtained are shown to be supported by existing observations

  15. Localized states in semiconductors

    International Nuclear Information System (INIS)

    Sarker, A.Q.

    1976-08-01

    The multi-valley effective mass formalism for the asymmetric energy surfaces developed in an earlier paper is extended for the calculations of the ground state energies of isocoric donors in Ge. The impurity potential is constructed from the k-dependent dielectric function of Ge and a variational trial wave function, belonging to an irreducible representation of the point group Tsub(d) of the Hamiltonian, is used. The calculated energy levels for the singlet A 1 and the triplet T 2 symmetries of the ls states for As in Ge is found to be of the same order (-9.6 to-12.8 meV) as observed experimentally; however, the predicted E(A 1 ) - E(T 2 ) splitting is rather too small (approximately -0.5 to -0.7 meV) compared with the observed value -4.23 meV

  16. Comprehensive study of ULF upstream waves observed in the topside ionosphere by CHAMP and on the ground

    Directory of Open Access Journals (Sweden)

    B. Heilig

    2007-03-01

    Full Text Available Based on magnetic field measurements from the satellite CHAMP, a detailed picture could be obtained of the upstream wave (UW distribution in the topside ionosphere. The low, near-polar orbit of CHAMP, covering all local times, allows the global distribution of this type of pulsation to be revealed. The observations from space are compared to recordings of the ground-based MM100 meridional array covering the latitude range 66° to 42° in magnetic coordinates. UWs show up very clearly in the compressional component of the satellite magnetic field data, whereas on the ground, their signature is found in the H component, but it is mixed with oscillations from field line resonant pulsations. Here we first introduce a procedure for an automated detection of UW signatures, both in ground and space data. Then a statistical analysis is presented of UW pulsations recorded during a 132-day period, centred on the autumn 2001 equinox. Observations in the top-side ionosphere reveal a clear latitudinal distribution of the amplitudes. Largest signals are observed at the equator. Minima show up at about 40° latitude. The coherence between ground and satellite wave signatures is high over wide latitude and longitude ranges. We make suggestions about the entry mechanism of UWs from the foreshock region into the magnetosphere. The clear UW signature in satellite recordings between −60° and 60° latitude allows for detailed investigations of the dependence on solar wind conditions. We test the control of solar wind speed, interplanetary magnetic field strength and cone angle on UWs. For the first time, it is possible to derive details of the Doppler-shift effect by modifying the UW frequency from direct observations. The results reconcile foreshock wave generation predictions with near-Earth observations.

  17. Variation in the defect structure of p-CdTe single crystals at the passage of the laser shock wave

    International Nuclear Information System (INIS)

    Baidullaeva, A.; Vlasenko, A.I.; Gorkovenko, B.L.; Lomovtsev, A.V.; Mozol', P.E.

    2000-01-01

    Variations in the minority-carrier lifetime, photoluminescence spectra, dark current and photocurrent temperature dependences of high-resistivity p-CdTe crystals under the action of the laser shock wave are investigated. It is shown that the variations in the aforementioned characteristics during the passage of the shock wave are defined by the generation of the nonequilibrium carriers from deep centers, and, after that, the variations are defined by the formation of intrinsic defects and their subsequent interaction with the defects existing in the initial crystals

  18. Inclusive decays of {eta}{sub b} into S- and P-wave charmonium states

    Energy Technology Data Exchange (ETDEWEB)

    He, Zhi-Guo, E-mail: hzgzlh@gmail.co [Institute of High Energy Physics, Chinese Academy of Science, P.O. Box 918(4), Beijing, 100049 (China); Theoretical Physics Center for Science Facilities, Beijing, 100049 (China); Li, Bai-Qing [Department of Physics, Huzhou Teachers College, Huzhou, 313000 (China)

    2010-09-20

    Inclusive S- and P-wave charmonium productions in the bottomonium ground state {eta}{sub b} decay are calculated at the leading order in the strong coupling constant {alpha}{sub s} and quarkonium internal relative velocity v in the framework of the NRQCD factorization approach. We find the contribution of {eta}{sub b{yields}{chi}c{sub J}}+gg followed by {chi}{sub c{sub J{yields}}}J/{psi}+{gamma} is also very important to inclusive J/{psi} production in the {eta}{sub b} decays, which maybe helpful to the investigation of the color-octet mechanism in the inclusive J/{psi} production in the {eta}{sub b} decays in the forthcoming LHCb and SuperB. As a complementary work, we also study the inclusive production of {eta}{sub c}, and {chi}{sub cJ} in the {eta}{sub b} decays, which may help us understand the X(3940) and X(3872) states.

  19. Determination of the Lowest-Energy States for the Model Distribution of Trained Restricted Boltzmann Machines Using a 1000 Qubit D-Wave 2X Quantum Computer.

    Science.gov (United States)

    Koshka, Yaroslav; Perera, Dilina; Hall, Spencer; Novotny, M A

    2017-07-01

    The possibility of using a quantum computer D-Wave 2X with more than 1000 qubits to determine the global minimum of the energy landscape of trained restricted Boltzmann machines is investigated. In order to overcome the problem of limited interconnectivity in the D-Wave architecture, the proposed RBM embedding combines multiple qubits to represent a particular RBM unit. The results for the lowest-energy (the ground state) and some of the higher-energy states found by the D-Wave 2X were compared with those of the classical simulated annealing (SA) algorithm. In many cases, the D-Wave machine successfully found the same RBM lowest-energy state as that found by SA. In some examples, the D-Wave machine returned a state corresponding to one of the higher-energy local minima found by SA. The inherently nonperfect embedding of the RBM into the Chimera lattice explored in this work (i.e., multiple qubits combined into a single RBM unit were found not to be guaranteed to be all aligned) and the existence of small, persistent biases in the D-Wave hardware may cause a discrepancy between the D-Wave and the SA results. In some of the investigated cases, introduction of a small bias field into the energy function or optimization of the chain-strength parameter in the D-Wave embedding successfully addressed difficulties of the particular RBM embedding. With further development of the D-Wave hardware, the approach will be suitable for much larger numbers of RBM units.

  20. Shell structure of the A = 6 ground states from three-body dynamics

    International Nuclear Information System (INIS)

    Lehman, D.R.; Parke, W.C.

    1983-01-01

    Three-body (αNN) models of the 6 He and 6 Li ground states are used to investigate their shell structure. Three models for each nucleus are considered: simple, full (nn), and full (np) for 6 He, and simple, full (0%), and full (4%) for 6 Li. The full models in both cases are obtained by including the S/sub 1/2/, P/sub 1/2/, and P/sub 3/2/ partial waves of the αN interaction, whereas the simple model truncates to only the strongly resonant P/sub 3/2/ wave. The 6 He full models distinguish between use of the nn or np parameters for the 1 S 0 NN interaction, while the 6 Li full models have either a pure 3 S 1 NN interaction (0%) or a 3 S 1 - 3 D 1 interaction that leads to a 4% d-wave component in the deuteron (4%). These models are used to calculate the probabilities of the orbital components of the wave functions, the configuration-space single-particle orbital densities, and the configuration-space two-particle wave function amplitudes in j-j coupling with the nucleon coordinates referred to the alpha particle as the ''core'' or ''center of force.'' The results are then compared with those from phenomenological and realistic-interaction shell models. Major findings of the comparison are the following: None of the shell models considered have a distribution of orbital probabilities across shells like that predicted by three-body models; the orbital rms radii from three-body models indicate an ordering of the orbits within shells, i.e., p/sub 1/2/ outside p/sub 3/2/, unlike oscillator shell models with a single oscillator parameter where the p-shell orbitals have the same shape; and, as expected, three-body orbital densities decay at large radial distances as exponentials rather than the too compact Gaussian falling off of oscillator shell models

  1. Wave-function functionals for the density

    International Nuclear Information System (INIS)

    Slamet, Marlina; Pan Xiaoyin; Sahni, Viraht

    2011-01-01

    We extend the idea of the constrained-search variational method for the construction of wave-function functionals ψ[χ] of functions χ. The search is constrained to those functions χ such that ψ[χ] reproduces the density ρ(r) while simultaneously leading to an upper bound to the energy. The functionals are thereby normalized and automatically satisfy the electron-nucleus coalescence condition. The functionals ψ[χ] are also constructed to satisfy the electron-electron coalescence condition. The method is applied to the ground state of the helium atom to construct functionals ψ[χ] that reproduce the density as given by the Kinoshita correlated wave function. The expectation of single-particle operators W=Σ i r i n , n=-2,-1,1,2, W=Σ i δ(r i ) are exact, as must be the case. The expectations of the kinetic energy operator W=-(1/2)Σ i ∇ i 2 , the two-particle operators W=Σ n u n , n=-2,-1,1,2, where u=|r i -r j |, and the energy are accurate. We note that the construction of such functionals ψ[χ] is an application of the Levy-Lieb constrained-search definition of density functional theory. It is thereby possible to rigorously determine which functional ψ[χ] is closer to the true wave function.

  2. Electronic ground support equipment for the Cluster Electric Field and Wave Experiment

    International Nuclear Information System (INIS)

    Sten, T.A.

    1992-10-01

    In a collaboration between ESA and NASA, ionosphere plasma structures will be studied by four indentical space probes to be launched in 1995 from French Guiana. The Electric Field and Wave (EFW) experiment will be designed to measure electric field and density fluctations by means of four sensors, each deployed on a 50 meter wire boom. In order to perform comprehensive tests and calibrations of the EFW experiment, computer controlled electronic ground support equipment has been developed. This report describes the hardware of the equipment, produced and assembled at the University of Oslo. 15 figs

  3. Self-similar decay to the marginally stable ground state in a model for film flow over inclined wavy bottoms

    Directory of Open Access Journals (Sweden)

    Tobias Hacker

    2012-04-01

    Full Text Available The integral boundary layer system (IBL with spatially periodic coefficients arises as a long wave approximation for the flow of a viscous incompressible fluid down a wavy inclined plane. The Nusselt-like stationary solution of the IBL is linearly at best marginally stable; i.e., it has essential spectrum at least up to the imaginary axis. Nevertheless, in this stable case we show that localized perturbations of the ground state decay in a self-similar way. The proof uses the renormalization group method in Bloch variables and the fact that in the stable case the Burgers equation is the amplitude equation for long waves of small amplitude in the IBL. It is the first time that such a proof is given for a quasilinear PDE with spatially periodic coefficients.

  4. Variational transition-state theory

    International Nuclear Information System (INIS)

    Truhlar, D.G.; Garrett, B.C.

    1980-01-01

    A general introduction to and some results from studies of a procedure called variational transition-state theory are presented. A fundamental assumption of this theory is that the net rate of forward reaction at equilibrium equals the equilibrium flux in the product direction through the transition state where the transition state is a surface in phase space dividing reactants from products. Classical generalized-transition-state-theory calculations for nine collinear systems are compared to classical trajectory calculations. This new technique should provide useful insight into the successes and failures of the conventional theory and useful quantitative estimates of possible errors on the predictions of conventional transition-state theory. This should also contribute to a more accurate theory now available for the practical calculations of chemical reaction rates and thermochemical and structural interpretations of rate processes

  5. Cluster decay of Ba isotopes from ground state and as an excited ...

    Indian Academy of Sciences (India)

    otherwise, inclusion of excitation energy decreases the T1/2 values. ... penetrates the nuclear barrier and reaches scission configuration after running .... between the ground-state energy levels of the parent nuclei and the ground-state energy.

  6. Using Tectonic Tremor to Constrain Seismic-wave Attenuation in Cascadia

    Science.gov (United States)

    Littel, G.; Thomas, A.; Baltay, A.

    2017-12-01

    In addition to fast, seismic slip, many subduction zones also host slow, largely aseismic slip, accompanied by a weak seismic signal known as tectonic tremor. Tremor is a small amplitude, low-frequency seismic signal that originates at the plate interface, down-dip of where large earthquakes typically occur. The Cascadia subduction zone has not seen a large megathrust earthquake since 1700, yet its recurrence interval of 350-500 years motivates heightened interest in understanding the seismic hazard of the region. Of great importance is to understand the degree to which waves are attenuated as they leave the plate interface and travel towards populated regions of interest. Ground motion prediction equations (GMPEs) relate ground motion to a number of parameters, including earthquake magnitude, depth, style of faulting, and anelastic attenuation, and are typically determined empirically from earthquake ground motion recordings. In Cascadia, however, earthquakes of the moderate size typically used to constrain GMPEs occur relatively infrequently compared to tectonic tremor events, which, in contrast, occur periodically approximately every 10-19 months. Studies have shown that the abundant tectonic tremor in Cascadia, despite its small amplitudes, can be used to constrain seismic wave attenuation in GMPEs. Here we quantify seismic wave attenuation and determine its spatial variations in Cascadia by performing an inversion using tremor ground motion amplitudes, taken as peak ground acceleration (PGA) and peak ground velocity (PGV) from 1 min window waveforms of each individual tremor event. We estimate the anelastic attenuation parameter for varying regional sections along the Cascadia margin. Changes in seismic-wave attenuation along the Cascadia Subduction Zone could result in significantly different ground motions in the event of a very large earthquake, hence quantifying attenuation may help to better estimate the severity of shaking in densely populated

  7. Magnetic properties of singlet ground state systems

    International Nuclear Information System (INIS)

    Diederix, K.M.

    1979-01-01

    Experiments are described determining the properties of a magnetic system consisting of a singlet ground state. Cu(NO 3 ) 2 .2 1/2H 2 O has been studied which is a system of S = 1/2 alternating antiferromagnetic Heisenberg chains. The static properties, spin lattice relaxation time and field-induced antiferromagnetically ordered state measurements are presented. Susceptibility and magnetic cooling measurements of other compounds are summarised. (Auth.)

  8. Gapless Spin-Liquid Ground State in the S =1 /2 Kagome Antiferromagnet

    Science.gov (United States)

    Liao, H. J.; Xie, Z. Y.; Chen, J.; Liu, Z. Y.; Xie, H. D.; Huang, R. Z.; Normand, B.; Xiang, T.

    2017-03-01

    The defining problem in frustrated quantum magnetism, the ground state of the nearest-neighbor S =1 /2 antiferromagnetic Heisenberg model on the kagome lattice, has defied all theoretical and numerical methods employed to date. We apply the formalism of tensor-network states, specifically the method of projected entangled simplex states, which combines infinite system size with a correct accounting for multipartite entanglement. By studying the ground-state energy, the finite magnetic order appearing at finite tensor bond dimensions, and the effects of a next-nearest-neighbor coupling, we demonstrate that the ground state is a gapless spin liquid. We discuss the comparison with other numerical studies and the physical interpretation of this result.

  9. Long range order in the ground state of two-dimensional antiferromagnets

    International Nuclear Information System (INIS)

    Neves, E.J.; Perez, J.F.

    1985-01-01

    The existence of long range order is shown in the ground state of the two-dimensional isotropic Heisenberg antiferromagnet for S >= 3/2. The method yields also long range order for the ground state of a larger class of anisotropic quantum antiferromagnetic spin systems with or without transverse magnetic fields. (Author) [pt

  10. Variational principles

    CERN Document Server

    Moiseiwitsch, B L

    2004-01-01

    This graduate-level text's primary objective is to demonstrate the expression of the equations of the various branches of mathematical physics in the succinct and elegant form of variational principles (and thereby illuminate their interrelationship). Its related intentions are to show how variational principles may be employed to determine the discrete eigenvalues for stationary state problems and to illustrate how to find the values of quantities (such as the phase shifts) that arise in the theory of scattering. Chapter-by-chapter treatment consists of analytical dynamics; optics, wave mecha

  11. Projection of heat waves variation over a warming climate in China

    Science.gov (United States)

    Yue, X.; Wu, S.; Pan, T.

    2016-12-01

    Heat waves (HW) have adverse impacts on economies, human health, societies and environment, which have been observed around the world and are expected to increase in a warming climate. However, the variations of HW under climate change over China are not clear yet. Using the HadGEM2-ES RCP4.5 and RCP8.5 daily maximum temperature and humidity dataset, variation of heat waves in China for 2021-2050 comparing to 1991-2000 as baseline were analyzed. The CMA-HI (Heat Index standardized by China Meteorological Administration) index was used to calculate the frequency and intensity of head waves. This paper classified the HW into three intensity levels including mild HW, moderate HW and severe HW , and defined a heat wave event (HWE) as that CMA-HI are all above or equal to 2.8 and keep at a intensity level more than five consecutive days. Results show that during 2021to 2050, the distribution area, frequency and duration of each intensity level have an increasing trend over China, and those of severe HW will increase mostly. The distribution area of mild, moderate and severe HW will increase 18%, 22%, 35% respectively. Average HWE frequency of each level will concentrate on 0.5-1instead of 0-0.3 in baseline period. Maximum frequency of each intensity can reach to almost 3 times a year. During 1991-2000, the average frequency of mild HW, moderate HW and severe HW kept a downward sequence. But it will change to increase in the future, and the shift occurs during 2031-2040. In addition, only severe HW duration will increase in the future. Its average value will increase from 9days to 13days, and keep a maximum duration of 42days.While the average duration of mild HW and moderate HW just keep almost 6 days and 8 days as usual. Regionally, both the frequency and duration will keep high value in the region of eastern China, central China, southern China and central Xinjiang autonomous region in the future. And only severe HW has a great change in distribution. Under RCP 8

  12. Optimized Variational 1D Boussinesq Modelling for broad-band waves over flat bottom

    NARCIS (Netherlands)

    Lakhturov, I.; Adytia, D.; van Groesen, Embrecht W.C.

    The Variational Boussinesq Model (VBM) for waves above a layer of ideal fluid conserves mass, momentum, energy, and has decreased dimensionality compared to the full problem. It is derived from the Hamiltonian formulation via an approximation of the kinetic energy, and can provide approximate

  13. Wave functions and two-electron probability distributions of the Hooke's-law atom and helium

    International Nuclear Information System (INIS)

    O'Neill, Darragh P.; Gill, Peter M. W.

    2003-01-01

    The Hooke's-law atom (hookium) provides an exactly soluble model for a two-electron atom in which the nuclear-electron Coulombic attraction has been replaced by a harmonic one. Starting from the known exact position-space wave function for the ground state of hookium, we present the momentum-space wave function. We also look at the intracules, two-electron probability distributions, for hookium in position, momentum, and phase space. These are compared with the Hartree-Fock results and the Coulomb holes (the difference between the exact and Hartree-Fock intracules) in position, momentum, and phase space are examined. We then compare these results with analogous results for the ground state of helium using a simple, explicitly correlated wave function

  14. Variational structure of inverse problems in wave propagation and vibration

    Energy Technology Data Exchange (ETDEWEB)

    Berryman, J.G.

    1995-03-01

    Practical algorithms for solving realistic inverse problems may often be viewed as problems in nonlinear programming with the data serving as constraints. Such problems are most easily analyzed when it is possible to segment the solution space into regions that are feasible (satisfying all the known constraints) and infeasible (violating some of the constraints). Then, if the feasible set is convex or at least compact, the solution to the problem will normally lie on the boundary of the feasible set. A nonlinear program may seek the solution by systematically exploring the boundary while satisfying progressively more constraints. Examples of inverse problems in wave propagation (traveltime tomography) and vibration (modal analysis) will be presented to illustrate how the variational structure of these problems may be used to create nonlinear programs using implicit variational constraints.

  15. Infrasonic induced ground motions

    Science.gov (United States)

    Lin, Ting-Li

    On January 28, 2004, the CERI seismic network recorded seismic signals generated by an unknown source. Our conclusion is that the acoustic waves were initiated by an explosive source near the ground surface. The meteorological temperature and effective sound speed profiles suggested existence of an efficient near-surface waveguide that allowed the acoustic disturbance to propagate to large distances. An explosion occurring in an area of forest and farms would have limited the number of eyewitnesses. Resolution of the source might be possible by experiment or by detailed analysis of the ground motion data. A seismo-acoustic array was built to investigate thunder-induced ground motions. Two thunder events with similar N-wave waveforms but different horizontal slownesses are chosen to evaluate the credibility of using thunder as a seismic source. These impulsive acoustic waves excited P and S reverberations in the near surface that depend on both the incident wave horizontal slowness and the velocity structure in the upper 30 meters. Nineteen thunder events were chosen to further investigate the seismo-acoustic coupling. The consistent incident slowness differences between acoustic pressure and ground motions suggest that ground reverberations were first initiated somewhat away from the array. Acoustic and seismic signals were used to generate the time-domain transfer function through the deconvolution technique. Possible non-linear interaction for acoustic propagation into the soil at the surface was observed. The reverse radial initial motions suggest a low Poisson's ratio for the near-surface layer. The acoustic-to-seismic transfer functions show a consistent reverberation series of the Rayleigh wave type, which has a systematic dispersion relation to incident slownesses inferred from the seismic ground velocity. Air-coupled Rayleigh wave dispersion was used to quantitatively constrain the near-surface site structure with constraints afforded by near-surface body

  16. Wave groupiness variations in the nearshore

    Science.gov (United States)

    List, J.H.

    1991-01-01

    This paper proposes a new definition of the groupiness factor, GF, based on the envelope of the incident-wave time series. It is shown that an envelope-based GF has several important advantages over the SIWEH-based groupiness factor, including objective criteria for determining the accuracy of the envelope function and well-defined numerical limits. Using this new GF, the variability of incident wave groupiness in the field is examined both temporally, in unbroken waves at a fixed location, and spatially, in a cross-shore array through the surf zone. Contrary to previous studies using the SIWEH-based GF, results suggest that incident wave groupiness may not be an independent parameter in unbroken waves; through a wide range of spectral shapes, from swell to storm waves, the groupiness did not vary significantly. As expected, the groupiness decreases rapidly as waves break through the surf zone, although significant wave height variability persists even through a saturated surf zone. The source of this inner surf zone groupiness is not identified; however, this observation implies that models of long wave generation must account for nonsteady radiation stress gradients landward of some narrow zone near the mean breakpoint. ?? 1991.

  17. Topological helical edge states in water waves over a topographical bottom

    KAUST Repository

    Wu, Shi qiao

    2017-11-27

    We present the discovery of topologically protected helical edge states in water wave systems, which are realized in water wave propagating over a topographical bottom whose height is modulated periodically in a two-dimensional triangular pattern. We develop an effective Hamiltonian to characterize the dispersion relation and use spin Chern numbers to classify the topology. Through full wave simulations we unambiguously demonstrate the robustness of the helical edge states which are immune to defects and disorders so that the backscattering loss is significantly reduced. A spin splitter is designed for water wave systems, where helical edge states with different spin orientations are spatially separated with each other, and potential applications are discussed.

  18. Topological helical edge states in water waves over a topographical bottom

    KAUST Repository

    Wu, Shi qiao; Wu, Ying; Mei, Jun

    2017-01-01

    We present the discovery of topologically protected helical edge states in water wave systems, which are realized in water wave propagating over a topographical bottom whose height is modulated periodically in a two-dimensional triangular pattern. We develop an effective Hamiltonian to characterize the dispersion relation and use spin Chern numbers to classify the topology. Through full wave simulations we unambiguously demonstrate the robustness of the helical edge states which are immune to defects and disorders so that the backscattering loss is significantly reduced. A spin splitter is designed for water wave systems, where helical edge states with different spin orientations are spatially separated with each other, and potential applications are discussed.

  19. Chiral Spin-Density Wave, Spin-Charge-Chern Liquid, and d+id Superconductivity in 1/4-Doped Correlated Electronic Systems on the Honeycomb Lattice

    Directory of Open Access Journals (Sweden)

    Shenghan Jiang

    2014-09-01

    Full Text Available Recently, two interesting candidate quantum phases—the chiral spin-density wave state featuring anomalous quantum Hall effect and the d+id superconductor—were proposed for the Hubbard model on the honeycomb lattice at 1/4 doping. Using a combination of exact diagonalization, density matrix renormalization group, the variational Monte Carlo method, and quantum field theories, we study the quantum phase diagrams of both the Hubbard model and the t-J model on the honeycomb lattice at 1/4 doping. The main advantage of our approach is the use of symmetry quantum numbers of ground-state wave functions on finite-size systems (up to 32 sites to sharply distinguish different quantum phases. Our results show that for 1≲U/t<40 in the Hubbard model and for 0.1ground state is either a chiral spin-density wave state or a spin-charge-Chern liquid, but not a d+id superconductor. However, in the t-J model, upon increasing J, the system goes through a first-order phase transition at J/t=0.80(2 into the d+id superconductor. Here, the spin-charge-Chern liquid state is a new type of topologically ordered quantum phase with Abelian anyons and fractionalized excitations. Experimental signatures of these quantum phases, such as tunneling conductance, are calculated. These results are discussed in the context of 1/4-doped graphene systems and other correlated electronic materials on the honeycomb lattice.

  20. Thermodynamic Ground States of Complex Oxide Heterointerfaces

    DEFF Research Database (Denmark)

    Gunkel, F.; Hoffmann-Eifert, S.; Heinen, R. A.

    2017-01-01

    The formation mechanism of 2-dimensional electron gases (2DEGs) at heterointerfaces between nominally insulating oxides is addressed with a thermodynamical approach. We provide a comprehensive analysis of the thermodynamic ground states of various 2DEG systems directly probed in high temperature...

  1. Quantum-Wave Equation and Heisenberg Inequalities of Covariant Quantum Gravity

    Directory of Open Access Journals (Sweden)

    Claudio Cremaschini

    2017-07-01

    Full Text Available Key aspects of the manifestly-covariant theory of quantum gravity (Cremaschini and Tessarotto 2015–2017 are investigated. These refer, first, to the establishment of the four-scalar, manifestly-covariant evolution quantum wave equation, denoted as covariant quantum gravity (CQG wave equation, which advances the quantum state ψ associated with a prescribed background space-time. In this paper, the CQG-wave equation is proved to follow at once by means of a Hamilton–Jacobi quantization of the classical variational tensor field g ≡ g μ ν and its conjugate momentum, referred to as (canonical g-quantization. The same equation is also shown to be variational and to follow from a synchronous variational principle identified here with the quantum Hamilton variational principle. The corresponding quantum hydrodynamic equations are then obtained upon introducing the Madelung representation for ψ , which provides an equivalent statistical interpretation of the CQG-wave equation. Finally, the quantum state ψ is proven to fulfill generalized Heisenberg inequalities, relating the statistical measurement errors of quantum observables. These are shown to be represented in terms of the standard deviations of the metric tensor g ≡ g μ ν and its quantum conjugate momentum operator.

  2. Classification of matrix-product ground states corresponding to one-dimensional chains of two-state sites of nearest neighbor interactions

    International Nuclear Information System (INIS)

    Fatollahi, Amir H.; Khorrami, Mohammad; Shariati, Ahmad; Aghamohammadi, Amir

    2011-01-01

    A complete classification is given for one-dimensional chains with nearest-neighbor interactions having two states in each site, for which a matrix product ground state exists. The Hamiltonians and their corresponding matrix product ground states are explicitly obtained.

  3. Excitation spectra and wave functions of quasiparticle bound states in bilayer Rashba superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Higashi, Yoichi, E-mail: higashiyoichi@ms.osakafu-u.ac.jp [Department of Mathematical Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai 599-8531 (Japan); Nagai, Yuki [CCSE, Japan Atomic Energy Agency, 178-4-4, Wakashiba, Kashiwa, Chiba 277-0871 (Japan); Yoshida, Tomohiro [Graduate School of Science and Technology, Niigata University, Niigata 950-2181 (Japan); Kato, Masaru [Department of Mathematical Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai 599-8531 (Japan); Yanase, Youichi [Department of Physics, Niigata University, Niigata 950-2181 (Japan)

    2015-11-15

    Highlights: • We focus on the pair-density wave state in bilayer Rashba superconductors. • The zero energy Bogoliubov wave functions are localized at the edge and vortex core. • We investigate the excitation spectra of edge and vortex bound states. - Abstract: We study the excitation spectra and the wave functions of quasiparticle bound states at a vortex and an edge in bilayer Rashba superconductors under a magnetic field. In particular, we focus on the quasiparticle states at the zero energy in the pair-density wave state in a topologically non-trivial phase. We numerically demonstrate that the quasiparticle wave functions with zero energy are localized at both the edge and the vortex core if the magnetic field exceeds the critical value.

  4. Dissociation energy of the ground state of NaH

    International Nuclear Information System (INIS)

    Huang, Hsien-Yu; Lu, Tsai-Lien; Whang, Thou-Jen; Chang, Yung-Yung; Tsai, Chin-Chun

    2010-01-01

    The dissociation energy of the ground state of NaH was determined by analyzing the observed near dissociation rovibrational levels. These levels were reached by stimulated emission pumping and fluorescence depletion spectroscopy. A total of 114 rovibrational levels in the ranges 9≤v '' ≤21 and 1≤J '' ≤14 were assigned to the X 1 Σ + state of NaH. The highest vibrational level observed was only about 40 cm -1 from the dissociation limit in the ground state. One quasibound state, above the dissociation limit and confined by the centrifugal barrier, was observed. Determining the vibrational quantum number at dissociation v D from the highest four vibrational levels yielded the dissociation energy D e =15 815±5 cm -1 . Based on new observations and available data, a set of Dunham coefficients and the rotationless Rydberg-Klein-Rees curve were constructed. The effective potential curve and the quasibound states were discussed.

  5. Feynman’s clock, a new variational principle, and parallel-in-time quantum dynamics

    Science.gov (United States)

    McClean, Jarrod R.; Parkhill, John A.; Aspuru-Guzik, Alán

    2013-01-01

    We introduce a discrete-time variational principle inspired by the quantum clock originally proposed by Feynman and use it to write down quantum evolution as a ground-state eigenvalue problem. The construction allows one to apply ground-state quantum many-body theory to quantum dynamics, extending the reach of many highly developed tools from this fertile research area. Moreover, this formalism naturally leads to an algorithm to parallelize quantum simulation over time. We draw an explicit connection between previously known time-dependent variational principles and the time-embedded variational principle presented. Sample calculations are presented, applying the idea to a hydrogen molecule and the spin degrees of freedom of a model inorganic compound, demonstrating the parallel speedup of our method as well as its flexibility in applying ground-state methodologies. Finally, we take advantage of the unique perspective of this variational principle to examine the error of basis approximations in quantum dynamics. PMID:24062428

  6. On the ground state of a model for compressed helium

    NARCIS (Netherlands)

    Seldam, C.A. ten; Groot, S.R. de

    1952-01-01

    In the problem of the “compressed helium atom”, the boundary condition that the wave function ψ must vanish at infinity (r = ∞), is replaced by: ψ = 0 at a finite r = r0. This problem is solved by a variational method, which for the limiting case of the free atom (r0 → ∞) coincides with one of

  7. Azimuth cut-off model for significant wave height investigation along coastal water of Kuala Terengganu, Malaysia

    Science.gov (United States)

    Marghany, Maged; Ibrahim, Zelina; Van Genderen, Johan

    2002-11-01

    The present work is used to operationalize the azimuth cut-off concept in the study of significant wave height. Three ERS-1 images have been used along the coastal waters of Terengganu, Malaysia. The quasi-linear transform was applied to map the SAR wave spectra into real ocean wave spectra. The azimuth cut-off was then used to model the significant wave height. The results show that azimuth cut-off varied with the different period of the ERS-1 images. This is because of the fact that the azimuth cut-off is a function of wind speed and significant wave height. It is of interest to find that the significant wave height modeled from azimuth cut-off is in good relation with ground wave conditions. It can be concluded that ERS-1 can be used as a monitoring tool in detecting the significant wave height variation. The azimuth cut-off can be used to model the significant wave height. This means that the quasi-linear transform could be a good application to significant wave height variation during different seasons.

  8. Magnetic excitons in singlet-ground-state ferromagnets

    DEFF Research Database (Denmark)

    Birgeneau, R.J.; Als-Nielsen, Jens Aage; Bucher, E.

    1971-01-01

    The authors report measurements of the dispersion of singlet-triplet magnetic excitons as a function of temperature in the singlet-ground-state ferromagnets fcc Pr and Pr3Tl. Well-defined excitons are observed in both the ferromagnetic and paramagnetic regions, but with energies which are nearly...

  9. The non-local Fisher–KPP equation: travelling waves and steady states

    International Nuclear Information System (INIS)

    Berestycki, Henri; Nadin, Grégoire; Perthame, Benoit; Ryzhik, Lenya

    2009-01-01

    We consider the Fisher–KPP equation with a non-local saturation effect defined through an interaction kernel φ(x) and investigate the possible differences with the standard Fisher–KPP equation. Our first concern is the existence of steady states. We prove that if the Fourier transform φ-circumflex(ξ) is positive or if the length σ of the non-local interaction is short enough, then the only steady states are u ≡ 0 and u ≡ 1. Next, we study existence of the travelling waves. We prove that this equation admits travelling wave solutions that connect u = 0 to an unknown positive steady state u ∞ (x), for all speeds c ≥ c * . The travelling wave connects to the standard state u ∞ (x) ≡ 1 under the aforementioned conditions: φ-circumflex(ξ) > 0 or σ is sufficiently small. However, the wave is not monotonic for σ large

  10. Relativistic configuration interaction calculation on the ground and excited states of iridium monoxide

    International Nuclear Information System (INIS)

    Suo, Bingbing; Yu, Yan-Mei; Han, Huixian

    2015-01-01

    We present the fully relativistic multi-reference configuration interaction calculations of the ground and low-lying excited electronic states of IrO for individual spin-orbit component. The lowest-lying state is calculated for Ω = 1/2, 3/2, 5/2, and 7/2 in order to clarify the ground state of IrO. Our calculation suggests that the ground state is of Ω = 1/2, which is highly mixed with 4 Σ − and 2 Π states in Λ − S notation. The two low-lying states 5/2 and 7/2 are nearly degenerate with the ground state and locate only 234 and 260 cm −1 above, respectively. The equilibrium bond length 1.712 Å and the harmonic vibrational frequency 903 cm −1 of the 5/2 state are close to the experimental measurement of 1.724 Å and 909 cm −1 , which suggests that the 5/2 state should be the low-lying state that contributes to the experimental spectra. Moreover, the electronic states that give rise to the observed transition bands are assigned for Ω = 5/2 and 7/2 in terms of the obtained excited energies and oscillator strengths

  11. Universal instability of dust ion-sound waves and dust-acoustic waves

    International Nuclear Information System (INIS)

    Tsytovich, V.N.; Watanabe, K.

    2002-01-01

    It is shown that the dust ion-sound waves (DISW) and the dust-acoustic waves (DAW) are universally unstable for wave numbers less than some critical wave number. The basic dusty plasma state is assumed to be quasi-neutral with balance of the plasma particle absorption on the dust particles and the ionization with the rate proportional to the electron density. An analytical expression for the critical wave numbers, for the frequencies and for the growth rates of DISW and DAW are found using the hydrodynamic description of dusty plasma components with self-consistent treatment of the dust charge variations and by taking into account the change of the ion and electron distributions in the dust charging process. Most of the previous treatment do not take into account the latter process and do not treat the basic state self-consistently. The critical lengths corresponding to these critical wave numbers can be easily achieved in the existing experiments. It is shown that at the wave numbers larger than the critical ones DISW and DAW have a large damping which was not treated previously and which can be also measured. The instabilities found in the present work on their non linear stage can lead to formation of different types of dust self-organized structures. (author)

  12. Rearrangements in ground and excited states

    CERN Document Server

    de Mayo, Paul

    1980-01-01

    Rearrangements in Ground and Excited States, Volume 2 covers essays on the theoretical approach of rearrangements; the rearrangements involving boron; and the molecular rearrangements of organosilicon compounds. The book also includes essays on the polytopal rearrangement at phosphorus; the rearrangement in coordination complexes; and the reversible thermal intramolecular rearrangements of metal carbonyls. Chemists and people involved in the study of rearrangements will find the book invaluable.

  13. Tweaking the spin-wave dispersion and suppressing the incommensurate phase in LiNiPO4 by iron substitution

    DEFF Research Database (Denmark)

    Li, Jiying; Jensen, Thomas Bagger Stibius; Andersen, Niels Hessel

    2009-01-01

    ) indicates the instability of the Ising-type ground state that eventually evolves into the incommensurate phase as the temperature is raised. The pure LiNiPO4 system (x=0) undergoes a first-order magnetic phase transition from a long-range incommensurate phase to an antiferromagnetic (AFM) ground state at TN......Elastic and inelastic neutron-scattering studies of Li(Ni1−xFex)PO4 single crystals reveal anomalous spin-wave dispersions along the crystallographic direction parallel to the characteristic wave vector of the magnetic incommensurate phase. The anomalous spin-wave dispersion (magnetic soft mode......=20.8 K. At 20% Fe concentrations, although the AFM ground state is to a large extent preserved as that of the pure system, the phase transition is second order, and the incommensurate phase is completely suppressed. Analysis of the dispersion curves using a Heisenberg spin Hamiltonian that includes...

  14. A Rigorous Investigation on the Ground State of the Penson-Kolb Model

    Science.gov (United States)

    Yang, Kai-Hua; Tian, Guang-Shan; Han, Ru-Qi

    2003-05-01

    By using either numerical calculations or analytical methods, such as the bosonization technique, the ground state of the Penson-Kolb model has been previously studied by several groups. Some physicists argued that, as far as the existence of superconductivity in this model is concerned, it is canonically equivalent to the negative-U Hubbard model. However, others did not agree. In the present paper, we shall investigate this model by an independent and rigorous approach. We show that the ground state of the Penson-Kolb model is nondegenerate and has a nonvanishing overlap with the ground state of the negative-U Hubbard model. Furthermore, we also show that the ground states of both the models have the same good quantum numbers and may have superconducting long-range order at the same momentum q = 0. Our results support the equivalence between these models. The project partially supported by the Special Funds for Major State Basic Research Projects (G20000365) and National Natural Science Foundation of China under Grant No. 10174002

  15. The variational cellular method for quantum mechanical applications : calculations of the ground and excited states of F2 and Ne2 molecules

    International Nuclear Information System (INIS)

    Leite, J.R.; Fazzio, A.; Lima, M.A.P.; Dias, A.M.; Rosato, A.; Segre, E.R.A.

    1980-12-01

    A self-consistent calculation based on the Variational Cellular Method is performed on the F 2 and Ne 2 molecules. The potential curve for the group state and for excited states of these molecules are determined. Spectroscopic constants related to the potential curves are also obtained. (Author) [pt

  16. The significant role of covalency in determining the ground state of cobalt phthalocyanines molecule

    Directory of Open Access Journals (Sweden)

    Jing Zhou

    2016-03-01

    Full Text Available To shed some light on the metal 3d ground state configuration of cobalt phthalocyanines system, so far in debate, we present an investigation by X-ray absorption spectroscopy (XAS at Co L2,3 edge and theoretical calculation. The density functional theory calculations reveal highly anisotropic covalent bond between central cobalt ion and nitrogen ligands, with the dominant σ donor accompanied by weak π-back acceptor interaction. Our combined experimental and theoretical study on the Co-L2,3 XAS spectra demonstrate a robust ground state of 2A1g symmetry that is built from 73% 3d7 character and 27% 3 d 8 L ¯ ( L ¯ denotes a ligand hole components, as the first excited-state with 2Eg symmetry lies about 158 meV higher in energy. The effect of anisotropic and isotropic covalency on the ground state was also calculated and the results indicate that the ground state with 2A1g symmetry is robust in a large range of anisotropic covalent strength while a transition of ground state from 2A1g to 2Eg configuration when isotropic covalent strength increases to a certain extent. Here, we address a significant anisotropic covalent effect of short Co(II-N bond on the ground state and suggest that it should be taken into account in determining the ground state of analogous cobalt complexes.

  17. Wave power for La Isla Bonita

    Energy Technology Data Exchange (ETDEWEB)

    Iglesias, G.; Carballo, R. [Univ. of Santiago de Compostela, Hydraulic Eng., EPS, Campus Univ. s/n, 27002 Lugo (Spain)

    2010-12-15

    The island of La Palma (Spain), dubbed La Isla Bonita for its beauty, is a UNESCO Biosphere Reserve in the Atlantic Ocean. The island's authorities are aiming for energy self-sufficiency based on wave energy and other renewables. In this research its wave resource is investigated using a 44-years hindcast dataset obtained through numerical modelling and validated with wave buoy records. First, its distribution around La Palma is studied. Significant variations are found, with the largest resource occurring off the north and northwest coasts; the northwest presents operational advantages (proximity to a port). Second, the seasonal variations in this area are studied. Wave energy is provided essentially by powerful NNW-NW swells in winter and autumn, by less energetic NNE-N waves in summer and spring. Finally, the resource is characterised in terms of sea states; it is found that the bulk of the energy is provided by waves between 9.5 s and 13.5 s of energy period and 1.5 m and 3.5 m of significant wave height, so the selection of the Wave Energy Converters to be installed should guarantee maximum efficiency in these ranges. (author)

  18. Symmetry breaking states of Bose-Einstein condensates in 1D double square well and optical lattice well

    International Nuclear Information System (INIS)

    Yuan Qingxin; Ding Guohui

    2005-01-01

    We investigate the phenomena of symmetry breaking and phase transition in the ground state of Bose-Einstein condensates (BECs). For BECs trapped in a double square well potential, we present symmetric and asymmetric ground states by using standing-wave expansion method. For BECs trapped in an optical lattice well potential (created by a standing laser wave, and not just an extension of the double square well potential), we reveal a phase transition by using plane-wave expansion method. At the same time we also study the ground state properties with changing the depth of potential and atomic interactions (restrict ourselves to the attractive regime)

  19. Nuclear quadrupole moment of the 99Tc ground state

    International Nuclear Information System (INIS)

    Errico, Leonardo; Darriba, German; Renteria, Mario; Tang Zhengning; Emmerich, Heike; Cottenier, Stefaan

    2008-01-01

    By combining first-principles calculations and existing nuclear magnetic resonance (NMR) experiments, we determine the quadrupole moment of the 9/2 + ground state of 99 Tc to be (-)0.14(3)b. This confirms the value of -0.129(20)b, which is currently believed to be the most reliable experimental determination, and disagrees with two earlier experimental values. We supply ab initio calculated electric-field gradients for Tc in YTc 2 and ZrTc 2 . If this calculated information would be combined with yet to be performed Tc-NMR experiments in these compounds, the error bar on the 99 Tc ground state quadrupole moment could be further reduced

  20. Measurement of the ground-state hyperfine splitting of antihydrogen

    CERN Document Server

    Juhász, B; Federmann, S

    2011-01-01

    The ASACUSA collaboration at the Antiproton Decelerator of CERN is planning to measure the ground-state hyperfine splitting of antihydrogen using an atomic beam line, consisting of a cusp trap as a source of partially polarized antihydrogen atoms, a radiofrequency spin-flip cavity, a superconducting sextupole magnet as spin analyser, and an antihydrogen detector. This will be a measurement of the antiproton magnetic moment, and also a test of the CPT invariance. Monte Carlo simulations predict that the antihydrogen ground-state hyperfine splitting can be determined with a relative precision of ~10−7. The first preliminary measurements of the hyperfine transitions will start in 2011.

  1. State Variation in Medical Imaging: Despite Great Variation, the Medicare Spending Decline Continues.

    Science.gov (United States)

    Rosenkrantz, Andrew B; Hughes, Danny R; Duszak, Richard

    2015-10-01

    The purpose of this study was to assess state-level trends in per beneficiary Medicare spending on medical imaging. Medicare part B 5% research identifiable files from 2004 through 2012 were used to compute national and state-by-state annual average per beneficiary spending on imaging. State-to-state geographic variation and temporal trends were analyzed. National average per beneficiary Medicare part B spending on imaging increased 7.8% annually between 2004 ($350.54) and its peak in 2006 ($405.41) then decreased 4.4% annually between 2006 and 2012 ($298.63). In 2012, annual per beneficiary spending was highest in Florida ($367.25) and New York ($355.67) and lowest in Ohio ($67.08) and Vermont ($72.78). Maximum state-to-state geographic variation increased over time, with the ratio of highest-spending state to lowest-spending state increasing from 4.0 in 2004 to 5.5 in 2012. Spending in nearly all states decreased since peaks in 2005 (six states) or 2006 (43 states). The average annual decrease among states was 5.1% ± 1.8% (range, 1.2-12.2%) The largest decrease was in Ohio. In only two states did per beneficiary spending increase (Maryland, 12.5% average annual increase since 2005; Oregon, 4.8% average annual increase since 2008). Medicare part B average per beneficiary spending on medical imaging declined in nearly every state since 2005 and 2006 peaks, abruptly reversing previously reported trends. Spending continued to increase, however, in Maryland and Oregon. Identification of state-level variation may facilitate future investigation of the potential effect of specific and regional changes in spending on patient access and outcomes.

  2. Electron scattering from the ground state of mercury

    International Nuclear Information System (INIS)

    Fursa, D.; Bray, I.

    2000-01-01

    Full text: Close-coupling calculations have been performed for electron scattering from the ground state of mercury. We have used non-relativistic convergent close-coupling computer code with only minor modifications in order to account for the most prominent relativistic effects. These are the relativistic shift effect and singlet-triplet mixing. Very good agreement with measurements of differential cross sections for elastic scattering and excitation of 6s6p 1 P state at all energies is obtained. It is well recognised that a consistent approach to electron scattering from heavy atoms (like mercury, with nuclear charge Z=80) must be based on a fully relativistic Dirac equations based technique. While development of such technique is under progress in our group, the complexity of the problem ensures that results will not be available in the near future. On other hand, there is considerable interest in reliable theoretical results for electron scattering from heavy atoms from both applications and the need to interpret existing experimental data. This is particularly the case for mercury, which is the major component in fluorescent lighting devices and has been the subject of intense experimental study since nineteen thirties. Similarly to our approach for alkaline-earth atoms we use a model of two valence electrons above an inert Hartree-Fock core to describe the mercury atom. Note that this model does not account for any core excited states which are present in the mercury discrete spectrum. The major effect of missing core-excited states is substantial underestimation of the static dipole polarizability of the mercury ground state (34 a.u.) and consequent underestimation of the forward scattering elastic cross sections. We correct for this by adding in the scattering calculations a phenomenological polarization potential. In order to obtain correct ground state ionization energy for mercury one has to account for the relativistic shift effect. We model this

  3. First simultaneous measurements of waves generated at the bow shock in the solar wind, the magnetosphere and on the ground

    Science.gov (United States)

    Clausen, L. B. N.; Yeoman, T. K.; Fear, R. C.; Behlke, R.; Lucek, E. A.; Engebretson, M. J.

    2009-01-01

    On 5 September 2002 the Geotail satellite observed the cone angle of the Interplanetary Magnetic Field (IMF) change to values below 30° during a 56 min interval between 18:14 and 19:10 UT. This triggered the generation of upstream waves at the bow shock, 13 RE downstream of the position of Geotail. Upstream generated waves were subsequently observed by Geotail between 18:30 and 18:48 UT, during times the IMF cone angle dropped below values of 10°. At 18:24 UT all four Cluster satellites simultaneously observed a sudden increase in wave power in all three magnetic field components, independent of their position in the dayside magnetosphere. We show that the 10 min delay between the change in IMF direction as observed by Geotail and the increase in wave power observed by Cluster is consistent with the propagation of the IMF change from the Geotail position to the bow shock and the propagation of the generated waves through the bow shock, magnetosheath and magnetosphere towards the position of the Cluster satellites. We go on to show that the wave power recorded by the Cluster satellites in the component containing the poloidal and compressional pulsations was broadband and unstructured; the power in the component containing toroidal oscillations was structured and shows the existence of multi-harmonic Alfvénic continuum waves on field lines. Model predictions of these frequencies fit well with the observations. An increase in wave power associated with the change in IMF direction was also registered by ground based magnetometers which were magnetically conjunct with the Cluster satellites during the event. To the best of our knowledge we present the first simultaneous observations of waves created by backstreaming ions at the bow shock in the solar wind, the dayside magnetosphere and on the ground.

  4. Reflection and diffraction of atomic de Broglie waves by evanescent laser waves. Bare-state method

    International Nuclear Information System (INIS)

    Feng, Xiaoping; Witte, N.S.; Hollenberg, C.L.; Opat, G.

    1994-01-01

    Two methods are presented for the investigation of the reflection and diffraction of atoms by gratings formed either by standing or travelling evanescent laser waves. Both methods use the bare-state rather than dressed-state picture. One method is based on the Born series, whereas the other is based on the Laplace transformation of the coupled differential equations. The two methods yield the same theoretical expressions for the reflected and diffracted atomic waves in the whole space including the interaction and the asymptotic regions. 1 ref., 1 fig

  5. Computing many-body wave functions with guaranteed precision: the first-order Møller-Plesset wave function for the ground state of helium atom.

    Science.gov (United States)

    Bischoff, Florian A; Harrison, Robert J; Valeev, Edward F

    2012-09-14

    We present an approach to compute accurate correlation energies for atoms and molecules using an adaptive discontinuous spectral-element multiresolution representation for the two-electron wave function. Because of the exponential storage complexity of the spectral-element representation with the number of dimensions, a brute-force computation of two-electron (six-dimensional) wave functions with high precision was not practical. To overcome the key storage bottlenecks we utilized (1) a low-rank tensor approximation (specifically, the singular value decomposition) to compress the wave function, and (2) explicitly correlated R12-type terms in the wave function to regularize the Coulomb electron-electron singularities of the Hamiltonian. All operations necessary to solve the Schrödinger equation were expressed so that the reconstruction of the full-rank form of the wave function is never necessary. Numerical performance of the method was highlighted by computing the first-order Møller-Plesset wave function of a helium atom. The computed second-order Møller-Plesset energy is precise to ~2 microhartrees, which is at the precision limit of the existing general atomic-orbital-based approaches. Our approach does not assume special geometric symmetries, hence application to molecules is straightforward.

  6. Properties of the {sup 7}He ground state from {sup 8}He neutron knockout

    Energy Technology Data Exchange (ETDEWEB)

    Aksyutina, Yu. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Fundamental Fysik, Chalmers Tekniska Hoegskola, S-412 96 Goeteborg (Sweden); Johansson, H.T. [Fundamental Fysik, Chalmers Tekniska Hoegskola, S-412 96 Goeteborg (Sweden); Aumann, T.; Boretzky, K. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Borge, M.J.G. [Instituto Estructura de la Materia, CSIC, E-28006 Madrid (Spain); Chatillon, A. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Chulkov, L.V. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Kurchatov Institute, RU-123182 Moscow (Russian Federation); Cortina-Gil, D. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); University of Santiago de Compostela, 15706 Santiago de Compostela (Spain); Pramanik, U. Datta [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064 (India); Emling, H. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Forssen, C. [Fundamental Fysik, Chalmers Tekniska Hoegskola, S-412 96 Goeteborg (Sweden); Fynbo, H.O.U. [Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark); Geissel, H.; Ickert, G. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Jonson, B. [Fundamental Fysik, Chalmers Tekniska Hoegskola, S-412 96 Goeteborg (Sweden)], E-mail: bjn@fy.chalmers.se; Kulessa, R. [Instytut Fizyki, Universytet Jagiellonski, PL-30-059 Krakow (Poland); Langer, C. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Lantz, M. [Fundamental Fysik, Chalmers Tekniska Hoegskola, S-412 96 Goeteborg (Sweden); LeBleis, T. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Lindahl, A.O. [Institutionen foer Fysik, University of Gothenburg, S-412 96 Goeteborg (Sweden)] (and others)

    2009-08-24

    The unbound nucleus {sup 7}He, produced in neutron-knockout reactions with a 240 MeV/u {sup 8}He beam in a liquid-hydrogen target, has been studied in an experiment at the ALADIN-LAND setup at GSI. From an R-matrix analysis the resonance parameters for {sup 7}He as well as the spectroscopic factor for the {sup 6}He(0{sup +}) + n configuration in its ground-state have been obtained. The spectroscopic factor is 0.61 confirming that {sup 7}He is not a pure single-particle state. An analysis of {sup 5}He data from neutron-knockout reactions of {sup 6}He in a carbon target reveals the presence of an s-wave component at low energies in the {alpha}+n relative energy spectrum. A possible low-lying exited state in {sup 7}He observed in neutron knockout data from {sup 8}He in a carbon target and tentatively interpreted as a I{sup {pi}}=1/2{sup -} state, could not be observed in the present experiment. Possible explanations of the shape difference between the {sup 7}He resonance obtained in the two knockout reactions are discussed in terms of target-dependence or different reaction mechanisms at relativistic energies.

  7. Counting states of black strings with traveling waves

    International Nuclear Information System (INIS)

    Horowitz, G.T.; Marolf, D.

    1997-01-01

    We consider a family of solutions to string theory which depend on arbitrary functions and contain regular event horizons. They describe six-dimensional extremal black strings with traveling waves and have an inhomogeneous distribution of momentum along the string. The structure of these solutions near the horizon is studied and the horizon area computed. We also count the number of BPS string states at weak coupling whose macroscopic momentum distribution agrees with that of the black string. It is shown that the number of such states is given by the Bekenstein-Hawking entropy of the black string with traveling waves. copyright 1997 The American Physical Society

  8. Ground-state and spectral properties of an asymmetric Hubbard ladder

    Science.gov (United States)

    Abdelwahab, Anas; Jeckelmann, Eric; Hohenadler, Martin

    2015-04-01

    We investigate a ladder system with two inequivalent legs, namely, a Hubbard chain and a one-dimensional electron gas. Analytical approximations, the density-matrix renormalization group method, and continuous-time quantum Monte Carlo simulations are used to determine ground-state properties, gaps, and spectral functions of this system at half-filling. Evidence for the existence of four different phases as a function of the Hubbard interaction and the rung hopping is presented. First, a Luttinger liquid exists at very weak interchain hopping. Second, a Kondo-Mott insulator with spin and charge gaps induced by an effective rung exchange coupling is found at moderate interchain hopping or strong Hubbard interaction. Third, a spin-gapped paramagnetic Mott insulator with incommensurate excitations and pairing of doped charges is observed at intermediate values of the rung hopping and the interaction. Fourth, the usual correlated band insulator is recovered for large rung hopping. We show that the wave numbers of the lowest single-particle excitations are different in each insulating phase. In particular, the three gapped phases exhibit markedly different spectral functions. We discuss the relevance of asymmetric two-leg ladder systems as models for atomic wires deposited on a substrate.

  9. Modeling Per Capita State Health Expenditure Variat...

    Data.gov (United States)

    U.S. Department of Health & Human Services — Modeling Per Capita State Health Expenditure Variation State-Level Characteristics Matter, published in Volume 3, Issue 4, of the Medicare and Medicaid Research...

  10. Experimental Measurement of Wave Field Variations around Wave Energy Converter Arrays

    OpenAIRE

    O'Boyle, Louise; Elsäßer, Björn; Whittaker, Trevor

    2017-01-01

    Wave energy converters (WECs) inherently extract energy from incident waves. For wave energy to become a significant power provider in the future, large farms of WECs will be required. This scale of energy extraction will increase the potential for changes in the local wave field and coastal environment. Assessment of these effects is necessary to inform decisions on the layout of wave farms for optimum power output and minimum environmental impact, as well as on potential site selection. An ...

  11. Reactive ground-state pathways are not ubiquitous in red/green cyanobacteriochromes.

    Science.gov (United States)

    Chang, Che-Wei; Gottlieb, Sean M; Kim, Peter W; Rockwell, Nathan C; Lagarias, J Clark; Larsen, Delmar S

    2013-09-26

    Recent characterization of the red/green cyanobacteriochrome (CBCR) NpR6012g4 revealed a high quantum yield for its forward photoreaction [J. Am. Chem. Soc. 2012, 134, 130-133] that was ascribed to the activity of hidden, productive ground-state intermediates. The dynamics of the pathways involving these ground-state intermediates was resolved with femtosecond dispersed pump-dump-probe spectroscopy, the first such study reported for any CBCR. To address the ubiquity of such second-chance initiation dynamics (SCID) in CBCRs, we examined the closely related red/green CBCR NpF2164g6 from Nostoc punctiforme. Both NpF2164g6 and NpR6012g4 use phycocyanobilin as the chromophore precursor and exhibit similar excited-state dynamics. However, NpF2164g6 exhibits a lower quantum yield of 32% for the generation of the isomerized Lumi-R primary photoproduct, compared to 40% for NpR6012g4. This difference arises from significantly different ground-state dynamics between the two proteins, with the SCID mechanism deactivated in NpF2164g6. We present an integrated inhomogeneous target model that self-consistently fits the pump-probe and pump-dump-probe signals for both forward and reverse photoreactions in both proteins. This work demonstrates that reactive ground-state intermediates are not ubiquitous phenomena in CBCRs.

  12. Quantum ground state and single-phonon control of a mechanical resonator.

    Science.gov (United States)

    O'Connell, A D; Hofheinz, M; Ansmann, M; Bialczak, Radoslaw C; Lenander, M; Lucero, Erik; Neeley, M; Sank, D; Wang, H; Weides, M; Wenner, J; Martinis, John M; Cleland, A N

    2010-04-01

    Quantum mechanics provides a highly accurate description of a wide variety of physical systems. However, a demonstration that quantum mechanics applies equally to macroscopic mechanical systems has been a long-standing challenge, hindered by the difficulty of cooling a mechanical mode to its quantum ground state. The temperatures required are typically far below those attainable with standard cryogenic methods, so significant effort has been devoted to developing alternative cooling techniques. Once in the ground state, quantum-limited measurements must then be demonstrated. Here, using conventional cryogenic refrigeration, we show that we can cool a mechanical mode to its quantum ground state by using a microwave-frequency mechanical oscillator-a 'quantum drum'-coupled to a quantum bit, which is used to measure the quantum state of the resonator. We further show that we can controllably create single quantum excitations (phonons) in the resonator, thus taking the first steps to complete quantum control of a mechanical system.

  13. A Ground State Tri-pí-Methane Rearrangement

    Czech Academy of Sciences Publication Activity Database

    Zimmerman, H. E.; Církva, Vladimír; Jiang, L.

    2000-01-01

    Roč. 41, č. 49 (2000), s. 9585-9587 ISSN 0040-4039 Institutional research plan: CEZ:AV0Z4072921 Keywords : tri-pi-methane * ground state Subject RIV: CC - Organic Chemistry Impact factor: 2.558, year: 2000

  14. P- and S-body wave tomography of the state of Nevada.

    Energy Technology Data Exchange (ETDEWEB)

    Preston, Leiph

    2010-04-01

    P- and S-body wave travel times collected from stations in and near the state of Nevada were inverted for P-wave velocity and the Vp/Vs ratio. These waves consist of Pn, Pg, Sn and Sg, but only the first arriving P and S waves were used in the inversion. Travel times were picked by University of Nevada Reno colleagues and were culled for inclusion in the tomographic inversion. The resulting tomographic model covers the entire state of Nevada to a depth of {approx}90 km; however, only the upper 40 km indicate relatively good resolution. Several features of interest are imaged including the Sierra Nevada, basin structures, and low velocities at depth below Yucca Mountain. These velocity structure images provide valuable information to aide in the interpretation of geothermal resource areas throughout the state on Nevada.

  15. Semileptonic decays of B{sub c} meson to S-wave charmonium states in the perturbative QCD approach

    Energy Technology Data Exchange (ETDEWEB)

    Rui, Zhou; Li, Hong; Wang, Guang-xin [North China University of Science and Technology, College of Sciences, Tangshan (China); Xiao, Ying [North China University of Science and Technology, College of Information Engineering, Tangshan (China)

    2016-10-15

    Inspired by the recent measurement of the ratio of B{sub c} branching fractions to J/ψπ{sup +} and J/ψμ{sup +}ν{sub μ} final states at the LHCb detector, we study the semileptonic decays of B{sub c} meson to the S-wave ground and radially excited 2S and 3S charmonium states with the perturbative QCD approach. After evaluating the form factors for the transitions B{sub c} → P,V, where P and V denote pseudoscalar and vector S-wave charmonia, respectively, we calculate the branching ratios for all these semileptonic decays. The theoretical uncertainty of hadronic input parameters are reduced by utilizing the light-cone wave function for the B{sub c} meson. It is found that the predicted branching ratios range from 10{sup -7} up to 10{sup -2} and could be measured by the future LHCb experiment. Our prediction for the ratio of branching fractions (BR(B{sub c}{sup +}→J/Ψπ{sup +}))/(BR(B{sub c}{sup +}→J/Ψμ{sup +}ν{sub μ})) is in good agreement with the data. For B{sub c} → Vlν{sub l} decays, the relative contributions of the longitudinal and transverse polarization are discussed in different momentum transfer squared regions. These predictions will be tested on the ongoing and forthcoming experiments. (orig.)

  16. Depth variations of P-wave azimuthal anisotropy beneath East Asia

    Science.gov (United States)

    Wei, W.; Zhao, D.; Xu, J.

    2017-12-01

    We present a new P-wave anisotropic tomographic model beneath East Asia by inverting a total of 1,488,531 P wave arrival-time data recorded by the regional seismic networks in East Asia and temporary seismic arrays deployed on the Tibetan Plateau. Our results provide important new insights into the subducting Indian, Pacific and Philippine Sea plates and mantle dynamics in East Asia. Our tomographic images show that the northern limit of the subducting Indian plate has reached the Jinsha River suture in eastern Tibet. A striking variation of P-wave azimuthal anisotropy is revealed in the Indian lithosphere: the fast velocity direction (FVD) is NE-SW beneath the Indian continent, whereas the FVD is arc parallel beneath the Himalaya and Tibetan Plateau, which may reflect re-orientation of minerals due to lithospheric extension, in response to the India-Eurasia collision. The FVD in the subducting Philippine Sea plate beneath the Ryukyu arc is NE-SW(trench parallel), which is consistent with the spreading direction of the West Philippine Basin during its initial opening stage, suggesting that it may reflect the fossil anisotropy. A circular pattern of FVDs is revealed around the Philippine Sea slab beneath SE China. We suggest that it reflects asthenospheric strain caused by toroidal mantle flow around the edge of the subducting slab. We find a striking variation of the FVD with depth in the subducting Pacific slab beneath the Northeast Japan arc. It may be caused by slab dehydration that changed elastic properties of the slab with depth. The FVD in the mantle wedge beneath the Northeast Japan and Ryukyu arcs is trench normal, which reflects subduction-induced convection. Beneath the Kuril and Izu-Bonin arcs where oblique subduction occurs, the FVD in the mantle wedge is nearly normal to the moving direction of the downgoing Pacific plate, suggesting that the oblique subduction together with the complex slab morphology have disturbed the mantle flow.

  17. Kinetic Alfven wave with density variation and loss-cone distribution function of multi-ions in PSBL region

    Science.gov (United States)

    Tamrakar, Radha; Varma, P.; Tiwari, M. S.

    2018-05-01

    Kinetic Alfven wave (KAW) generation due to variation of loss-cone index J and density of multi-ions (H+, He+ and O+) in the plasma sheet boundary layer region (PSBL) is investigated. Kinetic approach is used to derive dispersion relation of wave using Vlasov equation. Variation of frequency with respect to wide range of k⊥ρi (where k⊥ is wave vector across the magnetic field, ρi is gyroradius of ions and i denotes H+, He+ and O+ ions) is analyzed. It is found that each ion gyroradius and number density shows different effect on wave generation with varying width of loss-cone. KAW is generated with multi-ions (H+, He+ and O+) over wide regime for J=1 and shows dissimilar effect for J=2. Frequency is reduced with increasing density of gyrating He+ and O+ ions. Wave frequency is obtained within the reported range which strongly supports generation of kinetic Alfven waves. A sudden drop of frequency is also observed for H+ and He+ ion which may be due to heavy penetration of these ions through the loss-cone. The parameters of PSBL region are used for numerical calculation. The application of these results are in understanding the effect of gyrating multi-ions in transfer of energy and Poynting flux losses from PSBL region towards ionosphere and also describing the generation of aurora.

  18. Ab initio study of vibronic transitions between x2π and 12Σ+ electronic states of HCP+ ion

    Directory of Open Access Journals (Sweden)

    Stojanović Ljiljana

    2013-01-01

    Full Text Available The ground and low-lying excited doublet electronic states of the HCP+ ion were studied by means of multireference configuration interaction method. Vibronic energy levels of the X2Π state of Σ, Π, Δ, and Φ symmetry, up to the 2500 cm-1, have been calculated variationally, employing previously developed ab initio methods which take into account vibronic and spin-orbit interactions. Obtained vibronic wave functions were used to estimate transition moments between vibronic energy levels of the X2Π and 12Σ+ electronic states. Results were compared to available experimental and theoretical data. [Projekat Ministarstva nauke Republike Srbije, br. 172040

  19. Earthquake early warning using P-waves that appear after initial S-waves

    Science.gov (United States)

    Kodera, Y.

    2017-12-01

    As measures for underprediction for large earthquakes with finite faults and overprediction for multiple simultaneous earthquakes, Hoshiba (2013), Hoshiba and Aoki (2015), and Kodera et al. (2016) proposed earthquake early warning (EEW) methods that directly predict ground motion by computing the wave propagation of observed ground motion. These methods are expected to predict ground motion with a high accuracy even for complicated scenarios because these methods do not need source parameter estimation. On the other hand, there is room for improvement in their rapidity because they predict strong motion prediction mainly based on the observation of S-waves and do not explicitly use P-wave information available before the S-waves. In this research, we propose a real-time P-wave detector to incorporate P-wave information into these wavefield-estimation approaches. P-waves within a few seconds from the P-onsets are commonly used in many existing EEW methods. In addition, we focus on P-waves that may appear in the later part of seismic waves. Kurahashi and Irikura (2013) mentioned that P-waves radiated from strong motion generation areas (SMGAs) were recognizable after S-waves of the initial rupture point in the 2011 off the Pacific coast of Tohoku earthquake (Mw 9.0) (the Tohoku-oki earthquake). Detecting these P-waves would enhance the rapidity of prediction for the peak ground motion generated by SMGAs. We constructed a real-time P-wave detector that uses a polarity analysis. Using acceleration records in boreholes of KiK-net (band-pass filtered around 0.5-10 Hz with site amplification correction), the P-wave detector performed the principal component analysis with a sliding window of 4 s and calculated P-filter values (e.g. Ross and Ben-Zion, 2014). The application to the Tohoku-oki earthquake (Mw 9.0) showed that (1) peaks of P-filter that corresponded to SMGAs appeared in several stations located near SMGAs and (2) real-time seismic intensities (Kunugi et al

  20. Ground cross-modal impedance as a tool for analyzing ground/plate interaction and ground wave propagation.

    Science.gov (United States)

    Grau, L; Laulagnet, B

    2015-05-01

    An analytical approach is investigated to model ground-plate interaction based on modal decomposition and the two-dimensional Fourier transform. A finite rectangular plate subjected to flexural vibration is coupled with the ground and modeled with the Kirchhoff hypothesis. A Navier equation represents the stratified ground, assumed infinite in the x- and y-directions and free at the top surface. To obtain an analytical solution, modal decomposition is applied to the structure and a Fourier Transform is applied to the ground. The result is a new tool for analyzing ground-plate interaction to resolve this problem: ground cross-modal impedance. It allows quantifying the added-stiffness, added-mass, and added-damping from the ground to the structure. Similarity with the parallel acoustic problem is highlighted. A comparison between the theory and the experiment shows good matching. Finally, specific cases are investigated, notably the influence of layer depth on plate vibration.

  1. Gravitational Waves from Gravitational Collapse

    Directory of Open Access Journals (Sweden)

    Chris L. Fryer

    2011-01-01

    Full Text Available Gravitational-wave emission from stellar collapse has been studied for nearly four decades. Current state-of-the-art numerical investigations of collapse include those that use progenitors with more realistic angular momentum profiles, properly treat microphysics issues, account for general relativity, and examine non-axisymmetric effects in three dimensions. Such simulations predict that gravitational waves from various phenomena associated with gravitational collapse could be detectable with ground-based and space-based interferometric observatories. This review covers the entire range of stellar collapse sources of gravitational waves: from the accretion-induced collapse of a white dwarf through the collapse down to neutron stars or black holes of massive stars to the collapse of supermassive stars.

  2. Gravitational waves from gravitational collapse

    Energy Technology Data Exchange (ETDEWEB)

    Fryer, Christopher L [Los Alamos National Laboratory; New, Kimberly C [Los Alamos National Laboratory

    2008-01-01

    Gravitational wave emission from stellar collapse has been studied for nearly four decades. Current state-of-the-art numerical investigations of collapse include those that use progenitors with more realistic angular momentum profiles, properly treat microphysics issues, account for general relativity, and examine non-axisymmetric effects in three dimensions. Such simulations predict that gravitational waves from various phenomena associated with gravitational collapse could be detectable with ground-based and space-based interferometric observatories. This review covers the entire range of stellar collapse sources of gravitational waves: from the accretion induced collapse of a white dwarf through the collapse down to neutron stars or black holes of massive stars to the collapse of supermassive stars.

  3. Sub-Doppler spectroscopy of thioformaldehyde: Excited state perturbations and evidence for rotation-induced vibrational mixing in the ground state

    International Nuclear Information System (INIS)

    Clouthier, D.J.; Huang, G.; Adam, A.G.; Merer, A.J.

    1994-01-01

    High-resolution intracavity dye laser spectroscopy has been used to obtain sub-Doppler spectra of transitions to 350 rotational levels in the 4 1 0 band of the A 1 A 2 --X 1 A 1 electronic transition of thioformaldehyde. Ground state combination differences from the sub-Doppler spectra, combined with microwave and infrared data, have been used to improve the ground state rotational and centrifugal distortion constants of H 2 CS. The upper state shows a remarkable number of perturbations. The largest of these are caused by nearby triplet levels, with matrix elements of 0.05--0.15 cm -1 . A particularly clear singlet--triplet avoided crossing in K a ' = 7 has been shown to be caused by interaction with the F 1 component of the 3 1 6 2 vibrational level of the a 3 A 2 state. At least 53% of the S 1 levels show evidence of very small perturbations by high rovibronic levels of the ground state. The number of such perturbations is small at low J, but increases rapidly beyond J=5 such that 40%--80% of the observed S 1 levels of any given J are perturbed by ground state levels. Model calculations show that the density and J dependence of the number of perturbed levels can be explained if there is extensive rotation-induced mixing of the vibrational levels in the ground state

  4. Ground-water recharge in the arid and semiarid southwestern United States

    Science.gov (United States)

    Stonestrom, David A.; Constantz, Jim; Ferré, Ty P.A.; Leake, Stanley A.

    2007-01-01

    Ground-water recharge in the arid and semiarid southwestern United States results from the complex interplay of climate, geology, and vegetation across widely ranging spatial and temporal scales. Present-day recharge tends to be narrowly focused in time and space. Widespread water-table declines accompanied agricultural development during the twentieth century, demonstrating that sustainable ground-water supplies are not guaranteed when part of the extracted resource represents paleorecharge. Climatic controls on ground-water recharge range from seasonal cycles of summer monsoonal and winter frontal storms to multimillennial cycles of glacial and interglacial periods. Precipitation patterns reflect global-scale interactions among the oceans, atmosphere, and continents. Large-scale climatic influences associated with El Niño and Pacific Decadal Oscillations strongly, but irregularly, control weather in the study area, so that year-to-year variations in precipitation and ground-water recharge are large and difficult to predict. Proxy data indicate geologically recent periods of naturally occurring multidecadal droughts unlike any in the modern instrumental record. Any anthropogenically induced climate change will likely reduce ground-water recharge through diminished snowpack at higher elevations. Future changes in El Niño and monsoonal patterns, both crucial to precipitation in the study area, are highly uncertain in current models. Current land-use modifications influence ground-water recharge through vegetation, irrigation, and impermeable area. High mountain ranges bounding the study area—the San Bernadino Mountains and Sierra Nevada to the west, and the Wasatch and southern Colorado Rocky Mountains to the east—provide external geologic controls on ground-water recharge. Internal geologic controls stem from tectonic processes that led to numerous, variably connected alluvial-filled basins, exposure of extensive Paleozoic aquifers in mountainous recharge

  5. Estimating state of charge and health of lithium-ion batteries with guided waves using built-in piezoelectric sensors/actuators

    Science.gov (United States)

    Ladpli, Purim; Kopsaftopoulos, Fotis; Chang, Fu-Kuo

    2018-04-01

    This work presents the feasibility of monitoring state of charge (SoC) and state of health (SoH) of lithium-ion pouch batteries with acousto-ultrasonic guided waves. The guided waves are propagated and sensed using low-profile, built-in piezoelectric disc transducers that can be retrofitted onto off-the-shelf batteries. Both experimental and analytical studies are performed to understand the relationship between guided waves generated in a pitch-catch mode and battery SoC/SoH. The preliminary experiments on representative pouch cells show that the changes in time of flight (ToF) and signal amplitude (SA) resulting from shifts in the guided wave signals correlate strongly with the electrochemical charge-discharge cycling and aging. An analytical acoustic model is developed to simulate the variations in electrode moduli and densities during cycling, which correctly validates the absolute values and range of experimental ToF. It is further illustrated via a statistical study that ToF and SA can be used in a prediction model to accurately estimate SoC/SoH. Additionally, by using multiple sensors in a network configuration on the same battery, a significantly more reliable and accurate SoC/SoH prediction is achieved. The indicative results from this study can be extended to develop a unified guided-wave-based framework for SoC/SoH monitoring of many lithium-ion battery applications.

  6. Ground-state properties of a supersymmetric fermion chain

    International Nuclear Information System (INIS)

    Fendley, Paul; Hagendorf, Christian

    2011-01-01

    We analyze the ground state of a strongly interacting fermion chain with a supersymmetry. We conjecture a number of exact results, such as a hidden duality between weak and strong couplings. By exploiting a scale-free property of the perturbative expansions, we find exact expressions for the order parameters, yielding the critical exponents. We show that the ground state of this fermion chain and another model in the same universality class, the XYZ chain along a line of couplings, are both written in terms of the same polynomials. We demonstrate this explicitly for up to N = 24 sites and provide consistency checks for large N. These polynomials satisfy a recursion relation related to the Painlevé VI differential equation and, using a scale-free property of these polynomials, we derive a simple and exact formula for their N→∞ limit

  7. TSUNAMIS AND TSUNAMI-LIKE WAVES OF THE EASTERN UNITED STATES

    Directory of Open Access Journals (Sweden)

    James F. Lander

    2002-01-01

    Full Text Available The threat of tsunamis and tsunami-like waves hitting the eastern United States is very real despite a general impression to the contrary. We have cataloged 40 tsunamis and tsunami-like waves that have occurred in the eastern United States since 1600. Tsunamis were generated from such events as the 1755 Queen Anne’s earthquake, the Grand Banks event of 1929, the Charleston earthquake of 1886, and the New Madrid earthquakes of 1811-1812. The Queen Anne tsunami was observed as far away as St. Martin in the West Indies and is the only known teletsunami generated in this source region.Since subduction zones are absent around most of the Atlantic basin, tsunamis and tsunami-like waves along the United States East Coast are not generated from this traditional source, but appear, in most cases to be the result of slumping or landsliding associated with local earthquakes or with wave action associated with strong storms. Other sources of tsunamis and tsunami-like waves along the eastern seaboard have recently come to light including volcanic debris falls or catastrophic failure of volcanic slopes; explosive decompression of underwater methane deposits or oceanic meteor splashdowns. These sources are considered as well.

  8. Spatial and temporal variations of wave energy in the nearshore waters of the central west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Amrutha, M.M.; SanilKumar, V.

    >. At 9m water depth, the mean annual wave power is 6kWm-1 and interannual variations up to 19.3% are observed during 2009-2014. High wave energy (>20kWm-1) at the study area is essentially from the directional sector 245...

  9. Air-coupled seismic waves at long range from Apollo launchings.

    Science.gov (United States)

    Donn, W. L.; Dalins, I.; Mccarty, V.; Ewing, M.; Kaschak , G.

    1971-01-01

    Microphones and seismographs were co-located in arrays on Skidaway Island, Georgia, for the launchings of Apollo 13 and 14, 374 km to the south. Simultaneous acoustic and seismic waves were recorded for both events at times appropriate to the arrival of the acoustic waves from the source. The acoustic signal is relatively broadband compared to the nearly monochromatic seismic signal; the seismic signal is much more continuous than the more pulse-like acoustic signal; ground loading from the pressure variations of the acoustic waves is shown to be too small to account for the seismic waves; and the measured phase velocities of both acoustic and seismic waves across the local instrument arrays differ by less than 6 per cent and possibly 3 per cent if experimental error is included. It is concluded that the seismic waves are generated by resonant coupling to the acoustic waves along some 10 km of path on Skidaway Island.

  10. Non-degenerated Ground States and Low-degenerated Excited States in the Antiferromagnetic Ising Model on Triangulations

    Science.gov (United States)

    Jiménez, Andrea

    2014-02-01

    We study the unexpected asymptotic behavior of the degeneracy of the first few energy levels in the antiferromagnetic Ising model on triangulations of closed Riemann surfaces. There are strong mathematical and physical reasons to expect that the number of ground states (i.e., degeneracy) of the antiferromagnetic Ising model on the triangulations of a fixed closed Riemann surface is exponential in the number of vertices. In the set of plane triangulations, the degeneracy equals the number of perfect matchings of the geometric duals, and thus it is exponential by a recent result of Chudnovsky and Seymour. From the physics point of view, antiferromagnetic triangulations are geometrically frustrated systems, and in such systems exponential degeneracy is predicted. We present results that contradict these predictions. We prove that for each closed Riemann surface S of positive genus, there are sequences of triangulations of S with exactly one ground state. One possible explanation of this phenomenon is that exponential degeneracy would be found in the excited states with energy close to the ground state energy. However, as our second result, we show the existence of a sequence of triangulations of a closed Riemann surface of genus 10 with exactly one ground state such that the degeneracy of each of the 1st, 2nd, 3rd and 4th excited energy levels belongs to O( n), O( n 2), O( n 3) and O( n 4), respectively.

  11. Shear Wave Velocity for Evaluation of State of Cohesionless Soils with Fines

    Science.gov (United States)

    Lipiński, Mirosław J.; Wdowska, Małgorzata K.; Jaroń, Łukasz

    2017-10-01

    The paper concerns evaluation of cohesionless soils containing fines. In clean sands, state of soil is usually quantified by relative density DR with use of field techniques like static or dynamic probes. However, in cohesionless soils containing considerable amount of fines, relative density alone, which is based solely on void ratio values, is not representative. This results from the fact that in case of cohesionless soil there is no unique intrinsic compressibility line, like it is in case of cohesive soils. Thus state of soil depends not only on void ratio but also state of stress. For this reason it is necessary to look for an alternative means to quantify state of soils with fines. The paper concerns possibility of evaluation of state of soil containing various amount of fines on the basis of shear wave velocity measurement. The idea rests on the fact that void ratio and state of stress are the major factors which contribute to a state of soil and shear wave velocity as well. When measured shear wave velocities are normalised with respect to stresses the resulting values might be strictly correlated to void ratio. To validate this approach, an experimental test programme (based on series of sophisticated triaxial tests) was carried out on four kinds of sandy material containing various amount of fines up to 60%. The experimental data made possible to establish basic correlation between soil states and shear wave velocity for each kind of soil. Normalized shear wave velocity was compared with void ratio and state parameter as well. The obtained results revealed that determination of void ratio on the basis of shear wave velocity in a certain range of fines can be much more adequate than for clean sands. However, if the fines content exceeds certain value, the obtained correlation is no longer as good.

  12. A self-similar solution of a curved shock wave and its time-dependent force variation for a starting flat plate airfoil in supersonic flow

    Directory of Open Access Journals (Sweden)

    Zijun CHEN

    2018-02-01

    Full Text Available The problem of aeroelasticity and maneuvering of command surface and gust wing interaction involves a starting flow period which can be seen as the flow of an airfoil attaining suddenly an angle of attack. In the linear or nonlinear case, compressive Mach or shock waves are generated on the windward side and expansive Mach or rarefaction waves are generated on the leeward side. On each side, these waves are composed of an oblique steady state wave, a vertically-moving one-dimensional unsteady wave, and a secondary wave resulting from the interaction between the steady and unsteady ones. An analytical solution in the secondary wave has been obtained by Heaslet and Lomax in the linear case, and this linear solution has been borrowed to give an approximate solution by Bai and Wu for the nonlinear case. The structure of the secondary shock wave and the appearance of various force stages are two issues not yet considered in previous studies and has been studied in the present paper. A self-similar solution is obtained for the secondary shock wave, and the reason to have an initial force plateau as observed numerically is identified. Moreover, six theoretical characteristic time scales for pressure load variation are determined which explain the slope changes of the time-dependent force curve. Keywords: Force, Self-similar solution, Shock-shock interaction, Shock waves, Unsteady flow

  13. SU(2 Yang–Mills Theory: Waves, Particles, and Quantum Thermodynamics

    Directory of Open Access Journals (Sweden)

    Ralf Hofmann

    2016-08-01

    Full Text Available We elucidate how Quantum Thermodynamics at temperature T emerges from pure and classical S U ( 2 Yang–Mills theory on a four-dimensional Euclidean spacetime slice S 1 × R 3 . The concept of a (deconfining thermal ground state, composed of certain solutions to the fundamental, classical Yang–Mills equation, allows for a unified addressation of both (classical wave- and (quantum particle-like excitations thereof. More definitely, the thermal ground state represents the interplay between nonpropagating, periodic configurations which are electric-magnetically (antiselfdual in a non-trivial way and possess topological charge modulus unity. Their trivial-holonomy versions—Harrington–Shepard (HS (anticalorons—yield an accurate a priori estimate of the thermal ground state in terms of spatially coarse-grained centers, each containing one quantum of action ℏ localized at its inmost spacetime point, which induce an inert adjoint scalar field ϕ ( | ϕ | spatio-temporally constant. The field ϕ , in turn, implies an effective pure-gauge configuration, a μ gs , accurately describing HS (anticaloron overlap. Spatial homogeneity of the thermal ground-state estimate ϕ , a μ gs demands that (anticaloron centers are densely packed, thus representing a collective departure from (antiselfduality. Effectively, such a “nervous” microscopic situation gives rise to two static phenomena: finite ground-state energy density ρ gs and pressure P gs with ρ gs = − P gs as well as the (adjoint Higgs mechanism. The peripheries of HS (anticalorons are static and resemble (antiselfdual dipole fields whose apparent dipole moments are determined by | ϕ | and T, protecting them against deformation potentially caused by overlap. Such a protection extends to the spatial density of HS (anticaloron centers. Thus the vacuum electric permittivity ϵ 0 and magnetic permeability μ 0 , supporting the propagation of wave-like disturbances in the U ( 1 Cartan

  14. Correlation induced paramagnetic ground state in FeAl

    Czech Academy of Sciences Publication Activity Database

    Mohn, P.; Persson, C.; Blaha, P.; Schwarz, K.; Novák, Pavel; Eschrig, H.

    2001-01-01

    Roč. 87, č. 19 (2001), s. 196401-1-196401-4 ISSN 0031-9007 Institutional research plan: CEZ:AV0Z1010914 Keywords : FeAl * paramagnetic ground state Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 6.668, year: 2001

  15. Spin-density wave state in simple hexagonal graphite

    Science.gov (United States)

    Mosoyan, K. S.; Rozhkov, A. V.; Sboychakov, A. O.; Rakhmanov, A. L.

    2018-02-01

    Simple hexagonal graphite, also known as AA graphite, is a metastable configuration of graphite. Using tight-binding approximation, it is easy to show that AA graphite is a metal with well-defined Fermi surface. The Fermi surface consists of two sheets, each shaped like a rugby ball. One sheet corresponds to electron states, another corresponds to hole states. The Fermi surface demonstrates good nesting: a suitable translation in the reciprocal space superposes one sheet onto another. In the presence of the electron-electron repulsion, a nested Fermi surface is unstable with respect to spin-density-wave ordering. This instability is studied using the mean-field theory at zero temperature, and the spin-density-wave order parameter is evaluated.

  16. Construction of ground-state preserving sparse lattice models for predictive materials simulations

    Science.gov (United States)

    Huang, Wenxuan; Urban, Alexander; Rong, Ziqin; Ding, Zhiwei; Luo, Chuan; Ceder, Gerbrand

    2017-08-01

    First-principles based cluster expansion models are the dominant approach in ab initio thermodynamics of crystalline mixtures enabling the prediction of phase diagrams and novel ground states. However, despite recent advances, the construction of accurate models still requires a careful and time-consuming manual parameter tuning process for ground-state preservation, since this property is not guaranteed by default. In this paper, we present a systematic and mathematically sound method to obtain cluster expansion models that are guaranteed to preserve the ground states of their reference data. The method builds on the recently introduced compressive sensing paradigm for cluster expansion and employs quadratic programming to impose constraints on the model parameters. The robustness of our methodology is illustrated for two lithium transition metal oxides with relevance for Li-ion battery cathodes, i.e., Li2xFe2(1-x)O2 and Li2xTi2(1-x)O2, for which the construction of cluster expansion models with compressive sensing alone has proven to be challenging. We demonstrate that our method not only guarantees ground-state preservation on the set of reference structures used for the model construction, but also show that out-of-sample ground-state preservation up to relatively large supercell size is achievable through a rapidly converging iterative refinement. This method provides a general tool for building robust, compressed and constrained physical models with predictive power.

  17. Multiquark masses and wave functions through modified Green's function Monte Carlo method

    International Nuclear Information System (INIS)

    Kerbikov, B.O.; Polikarpov, M.I.; Shevchenko, L.V.

    1987-01-01

    The Modified Green's function Monte Carlo method (MGFMC) is used to calculate the masses and ground-state wave functions of multiquark systems in the potential model. The previously developed MGFMC is generalized in order to treat systems containing quarks with inequal masses. The obtained results are presented with the Cornell potential for the masses and the wave functions of light and heavy flavoured baryons and multiquark states (N=6, 9, 12) made of light quarks

  18. Surface/state correspondence and bulk local operators in pp-wave holography

    Directory of Open Access Journals (Sweden)

    Nakwoo Kim

    2015-12-01

    Full Text Available We apply the surface/state correspondence proposal of Miyaji et al. to IIB pp-waves and propose that the bulk local operators should be instantonic D-branes. In line with ordinary AdS/CFT correspondence, the bulk local operators in pp-waves also create a hole, or a boundary, in the dual gauge theory as pointed out by H. Verlinde, and by Y. Nakayama and H. Ooguri. We also present simple calculations which illustrate how to extract the spacetime metric of pp-waves from instantonic D-branes in boundary state formalism.

  19. Stable π-Extended p -Quinodimethanes: Synthesis and Tunable Ground States

    KAUST Repository

    Zeng, Zebing

    2014-12-18

    © 2014 The Chemical Society of Japan and Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. p-Quinodimethane (p-QDM) is a highly reactive hydrocarbon showing large biradical character in the ground state. It has been demonstrated that incorporation of the p-QDM moiety into an aromatic hydrocarbon framework could lead to new π-conjugated systems with significant biradical character and unique optical, electronic and magnetic properties. On the other hand, the extension of p-QDM is expected to result in molecules with even larger biradical character and higher reactivity. Therefore, the synthesis of stable π-extended p-QDMs is very challenging. In this Personal Account we will briefly discuss different stabilizing strategies and synthetic methods towards stable π-extended p-QDMs with tunable ground states and physical properties, including two types of polycyclic hydrocarbons: (1) tetrabenzo-Tschitschibabin\\'s hydrocarbons, and (2) tetracyano-rylenequinodimethanes. We will discuss how the aromaticity, substituents and steric hindrance play important roles in determining their ground states and properties. Incorporation of the p-quinodimethane moiety into aromatic hydrocarbon frameworks can lead to new π-conjugated systems with significant biradical character and unique optical, electronic and magnetic properties. Furthermore, the extension of p-QDM is expected to result in molecules with even larger biradical character and higher reactivity. In this Personal Account, different stabilizing strategies and synthetic methods towards stable π-extended p-QDMs with tunable ground states and physical properties are briefly discussed, including the roles of aromaticity, substituents and steric hindrance.

  20. Ground states of the massless Derezinski-Gerard model

    International Nuclear Information System (INIS)

    Ohkubo, Atsushi

    2009-01-01

    We consider the massless Derezinski-Gerard model introduced by Derezinski and Gerard in 1999. We give a sufficient condition for the existence of a ground state of the massless Derezinski-Gerard model without the assumption that the Hamiltonian of particles has compact resolvent.

  1. Ground State Structure of a Coupled 2-Fermion System in Supersymmetric Quantum Mechanics

    Science.gov (United States)

    Finster, Felix

    1997-05-01

    We prove the uniqueness of the ground state for a supersymmetric quantum mechanical system of two fermions and two bosons, which is closely related to theN=1 WZ-model. The proof is constructive and gives detailed information on what the ground state looks like

  2. A Continuous Family of Equilibria in Ferromagnetic Media are Ground States

    Science.gov (United States)

    Su, Xifeng; de la Llave, Rafael

    2017-09-01

    We show that a foliation of equilibria (a continuous family of equilibria whose graph covers all the configuration space) in ferromagnetic transitive models are ground states. The result we prove is very general, and it applies to models with long range and many-body interactions. As an application, we consider several models of networks of interacting particles including models of Frenkel-Kontorova type on Z^d and one-dimensional quasi-periodic media. The result above is an analogue of several results in the calculus of variations (fields of extremals) and in PDE's. Since the models we consider are discrete and long range, new proofs need to be given. We also note that the main hypothesis of our result (the existence of foliations of equilibria) is the conclusion (using KAM theory) of several recent papers. Hence, we obtain that the KAM solutions recently established are minimizers when the interaction is ferromagnetic and transitive (these concepts are defined later).

  3. Cluster expansion for ground states of local Hamiltonians

    Directory of Open Access Journals (Sweden)

    Alvise Bastianello

    2016-08-01

    Full Text Available A central problem in many-body quantum physics is the determination of the ground state of a thermodynamically large physical system. We construct a cluster expansion for ground states of local Hamiltonians, which naturally incorporates physical requirements inherited by locality as conditions on its cluster amplitudes. Applying a diagrammatic technique we derive the relation of these amplitudes to thermodynamic quantities and local observables. Moreover we derive a set of functional equations that determine the cluster amplitudes for a general Hamiltonian, verify the consistency with perturbation theory and discuss non-perturbative approaches. Lastly we verify the persistence of locality features of the cluster expansion under unitary evolution with a local Hamiltonian and provide applications to out-of-equilibrium problems: a simplified proof of equilibration to the GGE and a cumulant expansion for the statistics of work, for an interacting-to-free quantum quench.

  4. Atom localization and center-of-mass wave-function determination via multiple simultaneous quadrature measurements

    International Nuclear Information System (INIS)

    Evers, Joerg; Qamar, Shahid; Zubairy, M. Suhail

    2007-01-01

    We discuss localization and center-of-mass wave-function measurement of a quantum particle using multiple simultaneous dispersive interactions of the particle with different standing-wave fields. In particular, we consider objects with an internal structure consisting of a single ground state and several excited states. The transitions between ground and the corresponding excited states are coupled to the light fields in the dispersive limit, thus giving rise to a phase shift of the light field during the interaction. We show that multiple simultaneous measurements allow both an increase in the measurement or localization precision in a single direction and the performance of multidimensional measurements or localization. Further, we show that multiple measurements may relax the experimental requirements for each individual measurement

  5. Transient Analysis of Dispersive Power-Ground Plate Pairs With Arbitrarily Shaped Antipads by the DGTD Method With Wave Port Excitation

    KAUST Repository

    Li, Ping; Jiang, Li Jun; Bagci, Hakan

    2016-01-01

    A discontinuous Galerkin time-domain (DGTD) method analyzing signal/power integrity on multilayered power-ground parallel plate pairs is proposed. The excitation is realized by introducing wave ports on the antipads where electric/magnetic current

  6. A phase-plane analysis of localized frictional waves

    Science.gov (United States)

    Putelat, T.; Dawes, J. H. P.; Champneys, A. R.

    2017-07-01

    Sliding frictional interfaces at a range of length scales are observed to generate travelling waves; these are considered relevant, for example, to both earthquake ground surface movements and the performance of mechanical brakes and dampers. We propose an explanation of the origins of these waves through the study of an idealized mechanical model: a thin elastic plate subject to uniform shear stress held in frictional contact with a rigid flat surface. We construct a nonlinear wave equation for the deformation of the plate, and couple it to a spinodal rate-and-state friction law which leads to a mathematically well-posed problem that is capable of capturing many effects not accessible in a Coulomb friction model. Our model sustains a rich variety of solutions, including periodic stick-slip wave trains, isolated slip and stick pulses, and detachment and attachment fronts. Analytical and numerical bifurcation analysis is used to show how these states are organized in a two-parameter state diagram. We discuss briefly the possible physical interpretation of each of these states, and remark also that our spinodal friction law, though more complicated than other classical rate-and-state laws, is required in order to capture the full richness of wave types.

  7. Entanglement of two ground state neutral atoms using Rydberg blockade

    DEFF Research Database (Denmark)

    Miroshnychenko, Yevhen; Browaeys, Antoine; Evellin, Charles

    2011-01-01

    We report on our recent progress in trapping and manipulation of internal states of single neutral rubidium atoms in optical tweezers. We demonstrate the creation of an entangled state between two ground state atoms trapped in separate tweezers using the effect of Rydberg blockade. The quality...... of the entanglement is measured using global rotations of the internal states of both atoms....

  8. Coupled s-wave and d-wave states in the heavy-fermion superconductor U/sub 1-//sub x/Th/sub x/Be/sub 13/

    International Nuclear Information System (INIS)

    Langner, A.; Sahu, D.; George, T.F.

    1988-01-01

    In the heavy-fermion superconductor U/sub 1-//sub x/Th/sub x/Be/sub 13/, superconducting states coexist for thorium concentrations 0 ≤ x ≤ 0.06. Assuming s-wave and d-wave symmetries for these states, we derive a Ginzburg-Landau free-energy expression which couples s- and d-wave states and is rotationally invariant, in contrast to the free-energy expression proposed by P. Kumar and P. Woelfle [Phys. Rev. Lett. 59, 1954 (1987)]. We discuss in detail the consequences that follow from our free-energy relation. In particular, we predict that in the above system there are two eigenfrequencies associated with the dynamics of phase oscillations (internal Josephson effect) which are characteristic of the s-wave and d-wave states

  9. Spiral wave chimera states in large populations of coupled chemical oscillators

    Science.gov (United States)

    Totz, Jan Frederik; Rode, Julian; Tinsley, Mark R.; Showalter, Kenneth; Engel, Harald

    2018-03-01

    The coexistence of coherent and incoherent dynamics in a population of identically coupled oscillators is known as a chimera state1,2. Discovered in 20023, this counterintuitive dynamical behaviour has inspired extensive theoretical and experimental activity4-15. The spiral wave chimera is a particularly remarkable chimera state, in which an ordered spiral wave rotates around a core consisting of asynchronous oscillators. Spiral wave chimeras were theoretically predicted in 200416 and numerically studied in a variety of systems17-23. Here, we report their experimental verification using large populations of nonlocally coupled Belousov-Zhabotinsky chemical oscillators10,18 in a two-dimensional array. We characterize previously unreported spatiotemporal dynamics, including erratic motion of the asynchronous spiral core, growth and splitting of the cores, as well as the transition from the chimera state to disordered behaviour. Spiral wave chimeras are likely to occur in other systems with long-range interactions, such as cortical tissues24, cilia carpets25, SQUID metamaterials26 and arrays of optomechanical oscillators9.

  10. Ground State Energy of the Modified Nambu-Goto String

    Science.gov (United States)

    Hadasz, Leszek

    We calculate, using zeta function regularization method, semiclassical energy of the Nambu-Goto string supplemented with the boundary, Gauss-Bonnet term in the action and discuss the tachyonic ground state problem.

  11. Ground state energy of the modified Nambu-Goto string

    OpenAIRE

    Hadasz, Leszek

    1997-01-01

    We calculate, using zeta function regularization method, semiclassical energy of the Nambu-Goto string supplemented with the boundary, Gauss-Bonnet term in the action and discuss the tachyonic ground state problem.

  12. State Variation in Medicaid Reimbursements for Orthopaedic Surgery.

    Science.gov (United States)

    Lalezari, Ramin M; Pozen, Alexis; Dy, Christopher J

    2018-02-07

    Medicaid reimbursements are determined by each state and are subject to variability. We sought to quantify this variation for commonly performed inpatient orthopaedic procedures. The 10 most commonly performed inpatient orthopaedic procedures, as ranked by the Healthcare Cost and Utilization Project (HCUP) National Inpatient Sample, were identified for study. Medicaid reimbursement amounts for those procedures were benchmarked to state Medicare reimbursement amounts in 3 ways: (1) ratio, (2) dollar difference, and (3) dollar difference divided by the relative value unit (RVU) amount. Variability was quantified by determining the range and coefficient of variation for those reimbursement amounts. The range of variability of Medicaid reimbursements among states exceeded $1,500 for all 10 procedures. The coefficients of variation ranged from 0.32 (hip hemiarthroplasty) to 0.57 (posterior or posterolateral lumbar interbody arthrodesis) (a higher coefficient indicates greater variability), compared with 0.07 for Medicare reimbursements for all 10 procedures. Adjusted as a dollar difference between Medicaid and Medicare per RVU, the median values ranged from -$8/RVU (total knee arthroplasty) to -$17/RVU (open reduction and internal fixation of the femur). Variability of Medicaid reimbursement for inpatient orthopaedic procedures among states is substantial. This variation becomes especially remarkable given recent policy shifts toward focusing reimbursements on value.

  13. Singlet Ground State Magnetism: III Magnetic Excitons in Antiferromagnetic TbP

    DEFF Research Database (Denmark)

    Knorr, K.; Loidl, A.; Kjems, Jørgen

    1981-01-01

    The dispersion of the lowest magnetic excitations of the singlet ground state system TbP has been studied in the antiferromagnetic phase by inelastic neutron scattering. The magnetic exchange interaction and the magnetic and the rhombohedral molecular fields have been determined.......The dispersion of the lowest magnetic excitations of the singlet ground state system TbP has been studied in the antiferromagnetic phase by inelastic neutron scattering. The magnetic exchange interaction and the magnetic and the rhombohedral molecular fields have been determined....

  14. Unambiguous assignment of the ground state of a nearly degenerate cluster

    International Nuclear Information System (INIS)

    Gutsev, G. L.; Khanna, S. N.; Jena, P.

    2000-01-01

    A synergistic approach that combines first-principles theory and electron photodetachment experiment is shown to be able to uniquely identify the ground state of a nearly degenerate cluster in the gas phase. Additionally, this approach can complement the Stern-Gerlach technique in determining the magnetic moment of small clusters unambiguously. The method, applied to a Fe 3 cluster, reveals its ground state to have a magnetic moment of 10μ B --in contrast with earlier predictions. (c) 2000 The American Physical Society

  15. Rotating swings—a theme with variations

    Science.gov (United States)

    Pendrill, Ann-Marie

    2016-01-01

    Rotating swing rides can be found in many amusement parks, in many different versions. The ‘wave swinger’ ride, which introduces a wave motion by tilting the roof, is among the classical amusement rides that are found in many different parks, in different sizes, from a number of different makes and names, and varying thematization. The ‘StarFlyer’ is a more recent version, adding the thrill of lifting the riders 60 m or more over the ground. These rotating swing rides involve beautiful physics, often surprising, but easily observed, when brought to attention. The rides can be used for student worksheet tasks and assignments of different degrees of difficulty, across many math and physics topics. This paper presents a number of variations of student tasks relating to the theme of rotating swing rides.

  16. Variational Perturbation Treatment of the Confined Hydrogen Atom

    Science.gov (United States)

    Montgomery, H. E., Jr.

    2011-01-01

    The Schrodinger equation for the ground state of a hydrogen atom confined at the centre of an impenetrable cavity is treated using variational perturbation theory. Energies calculated from variational perturbation theory are comparable in accuracy to the results from a direct numerical solution. The goal of this exercise is to introduce the…

  17. Using periodicity to mitigate ground vibration

    DEFF Research Database (Denmark)

    Andersen, Lars Vabbersgaard

    2015-01-01

    Introduction of trenches, barriers and wave impeding blocks on the transmission path between a source and receiver can be used for mitigation of ground vibration. However, to be effective a barrier must have a depth of about one wavelength of the waves to be mitigated. Hence, while great reductions......: A soil with periodic stiffening (ground improvement) and a ground with periodic changes in the surface elevation obtained by artificial landscaping. By means of a two-dimensional finite-element model, the stiffness and mass matrices are determined for a single cell of the ground with horizonal...

  18. Gravitational Waves from Gravitational Collapse.

    Science.gov (United States)

    Fryer, Chris L; New, Kimberly C B

    2011-01-01

    Gravitational-wave emission from stellar collapse has been studied for nearly four decades. Current state-of-the-art numerical investigations of collapse include those that use progenitors with more realistic angular momentum profiles, properly treat microphysics issues, account for general relativity, and examine non-axisymmetric effects in three dimensions. Such simulations predict that gravitational waves from various phenomena associated with gravitational collapse could be detectable with ground-based and space-based interferometric observatories. This review covers the entire range of stellar collapse sources of gravitational waves: from the accretion-induced collapse of a white dwarf through the collapse down to neutron stars or black holes of massive stars to the collapse of supermassive stars. Supplementary material is available for this article at 10.12942/lrr-2011-1.

  19. Extreme Wave Analysis by Integrating Model and Wave Buoy Data

    Directory of Open Access Journals (Sweden)

    Fabio Dentale

    2018-03-01

    Full Text Available Estimating the extreme values of significant wave height (HS, generally described by the HS return period TR function HS(TR and by its confidence intervals, is a necessity in many branches of coastal science and engineering. The availability of indirect wave data generated by global and regional wind and wave model chains have brought radical changes to the estimation procedures of such probability distribution—weather and wave modeling systems are routinely run all over the world, and HS time series for each grid point are produced and published after assimilation (analysis of the ground truth. However, while the sources of such indirect data are numerous, and generally of good quality, many aspects of their procedures are hidden to the users, who cannot evaluate the reliability and the limits of the HS(TR deriving from such data. In order to provide a simple engineering tool to evaluate the probability of extreme sea-states as well as the quality of such estimates, we propose here a procedure based on integrating HS time series generated by model chains with those recorded by wave buoys in the same area.

  20. Rayleigh approximation to ground state of the Bose and Coulomb glasses

    Science.gov (United States)

    Ryan, S. D.; Mityushev, V.; Vinokur, V. M.; Berlyand, L.

    2015-01-01

    Glasses are rigid systems in which competing interactions prevent simultaneous minimization of local energies. This leads to frustration and highly degenerate ground states the nature and properties of which are still far from being thoroughly understood. We report an analytical approach based on the method of functional equations that allows us to construct the Rayleigh approximation to the ground state of a two-dimensional (2D) random Coulomb system with logarithmic interactions. We realize a model for 2D Coulomb glass as a cylindrical type II superconductor containing randomly located columnar defects (CD) which trap superconducting vortices induced by applied magnetic field. Our findings break ground for analytical studies of glassy systems, marking an important step towards understanding their properties. PMID:25592417

  1. Modeling of the stress-strain state of the ground mass contaminated with peracetic acid

    Directory of Open Access Journals (Sweden)

    Levenko Anna

    2017-01-01

    Full Text Available None of the methods described previously provides a solution to the problem that deals with the SSS evaluation of the ground mass which is under the influence of chemically active substances and, in particular, under the influence of peracetic acid. The stress-strain state of the ground mass contaminated with peracetic acid was estimated. Stresses occurring in the ground mass in the natural state were determined after the entry of acid into it and after the chemical fixation of it with sodium silicate. All the parameters of the stress-strain state of the ground mass were obtained under a number of physical and mechanical conditions. It was determined that following the work on the silicatization of the ground mass contaminated with peracetic acid the quantity of strain decreased by 26.11 to 48.9%. The comparison of the results of stress calculations indicates the stress reduction in the ground mass in 1.8 – 2.6 times after its fixing.

  2. Kohn-Sham Theory for Ground-State Ensembles

    International Nuclear Information System (INIS)

    Ullrich, C. A.; Kohn, W.

    2001-01-01

    An electron density distribution n(r) which can be represented by that of a single-determinant ground state of noninteracting electrons in an external potential v(r) is called pure-state v -representable (P-VR). Most physical electronic systems are P-VR. Systems which require a weighted sum of several such determinants to represent their density are called ensemble v -representable (E-VR). This paper develops formal Kohn-Sham equations for E-VR physical systems, using the appropriate coupling constant integration. It also derives local density- and generalized gradient approximations, and conditions and corrections specific to ensembles

  3. Ground state structure of a coupled 2-fermion system in supersymmetric quantum mechanics

    International Nuclear Information System (INIS)

    Finster, F.

    1997-01-01

    We prove the uniqueness of the ground state for a supersymmetric quantum mechanical system of two fermions and two bosons, which is closely related to the N=1 WZ-model. The proof is constructive and gives detailed information on what the ground state looks like. copyright 1997 Academic Press, Inc

  4. Ab initio calculation of the electronic structures of the 7∑+ ground and A 7Π and a 5∑+ excited states of MnH

    Science.gov (United States)

    Tomonari, Mutsumi; Nagashima, Umpei; Hirano, Tsuneo

    2009-04-01

    Electronic structures and molecular constants of the ground ∑7+ and low-lying A 7Π and a ∑5+ electronic excited states of the MnH molecule were studied by multireference single and double excitation configuration interaction (MR-SDCI) with Davidson's correction (+Q) calculations under exact C∞v symmetry using Slater-type basis sets. To correctly describe the ∑7+ electronic ground state, X ∑7+, at the MR-SDCI+Q calculation, we employed a large number of reference configurations in terms of the state-averaged complete active space self-consistent field (CASSCF) orbitals, taking into account the contribution from the B ∑7+ excited state. The A 7Π and a ∑5+ states can well be described by the MR-SDCI wave functions based on the CASSCF orbitals obtained for the lowest state only. In the MR-SDCI+Q, calculations of the X ∑7+, A 7Π, and a ∑5+ states required 16, 7, and 17 reference configurations, respectively. Molecular constants, i.e., re and ωe of these states and excitation energy from the X ∑7+ state, obtained at the MR-SDCI+Q level, showed a good agreement with experimental values. The small remaining differences may be accounted for by taking relativistic effects into account.

  5. Ab initio calculation of the electronic structures of the (7)Sigma+ ground and A (7)Pi and a (5)Sigma+ excited states of MnH.

    Science.gov (United States)

    Tomonari, Mutsumi; Nagashima, Umpei; Hirano, Tsuneo

    2009-04-21

    Electronic structures and molecular constants of the ground (7)Sigma(+) and low-lying A (7)Pi and a (5)Sigma(+) electronic excited states of the MnH molecule were studied by multireference single and double excitation configuration interaction (MR-SDCI) with Davidson's correction (+Q) calculations under exact C(infinity v) symmetry using Slater-type basis sets. To correctly describe the (7)Sigma(+) electronic ground state, X (7)Sigma(+), at the MR-SDCI+Q calculation, we employed a large number of reference configurations in terms of the state-averaged complete active space self-consistent field (CASSCF) orbitals, taking into account the contribution from the B (7)Sigma(+) excited state. The A (7)Pi and a (5)Sigma(+) states can well be described by the MR-SDCI wave functions based on the CASSCF orbitals obtained for the lowest state only. In the MR-SDCI+Q, calculations of the X (7)Sigma(+), A (7)Pi, and a (5)Sigma(+) states required 16, 7, and 17 reference configurations, respectively. Molecular constants, i.e., r(e) and omega(e) of these states and excitation energy from the X (7)Sigma(+) state, obtained at the MR-SDCI+Q level, showed a good agreement with experimental values. The small remaining differences may be accounted for by taking relativistic effects into account.

  6. Electronic states of a hydrogenic impurity in a zinc-blende GaN/AlGaN quantum well

    International Nuclear Information System (INIS)

    Pattammal, M.; Peter, A. John

    2010-01-01

    Binding energies of ground and a few low lying excited states of a hydrogenic donor confined in a zinc-blende GaN/AlGaN quantum well are investigated. They are computed within the framework of single band effective mass approximation, by means of a variational approach. The donor states are investigated with the various impurity positions as a function of well width. The calculations have been carried out with the inclusion of conduction band non-parabolicity through the energy dependent effective mass. The variational solutions have been improved by using a two-parametric trial wavefunction. The results seem better and good agreement with the other investigators. To support our results, we observe that the values of variational parameters are consistent when two parameter wave function is used. We find that the inclusion of non-parabolic effects leads to more binding for all the values of well width and is significant for narrow wells. The results are compared with the existing available literature.

  7. Electronic states of a hydrogenic impurity in a zinc-blende GaN/AlGaN quantum well

    Energy Technology Data Exchange (ETDEWEB)

    Pattammal, M. [Dept.of Physics, Yadava College Coeducational Institute, Madurai 625 014 (India); Peter, A. John, E-mail: a.john.peter@gmail.com [Dept.of Physics, Govt. Arts and Science College, Melur 625 106 (India)

    2010-09-01

    Binding energies of ground and a few low lying excited states of a hydrogenic donor confined in a zinc-blende GaN/AlGaN quantum well are investigated. They are computed within the framework of single band effective mass approximation, by means of a variational approach. The donor states are investigated with the various impurity positions as a function of well width. The calculations have been carried out with the inclusion of conduction band non-parabolicity through the energy dependent effective mass. The variational solutions have been improved by using a two-parametric trial wavefunction. The results seem better and good agreement with the other investigators. To support our results, we observe that the values of variational parameters are consistent when two parameter wave function is used. We find that the inclusion of non-parabolic effects leads to more binding for all the values of well width and is significant for narrow wells. The results are compared with the existing available literature.

  8. A simple parameter-free wavefunction for the ground state of two-electron atoms

    International Nuclear Information System (INIS)

    Ancarani, L U; Rodriguez, K V; Gasaneo, G

    2007-01-01

    We propose a simple and pedagogical wavefunction for the ground state of two-electron atoms which (i) is parameter free (ii) satisfies all two-particle cusp conditions (iii) yields reasonable ground-state energies, including the prediction of a bound state for H - . The mean energy, and other mean physical quantities, is evaluated analytically. The simplicity of the result can be useful as an easy-to-use wavefunction when testing collision models

  9. Trapping cold ground state argon atoms for sympathetic cooling of molecules

    OpenAIRE

    Edmunds, P. D.; Barker, P. F.

    2014-01-01

    We trap cold, ground-state, argon atoms in a deep optical dipole trap produced by a build-up cavity. The atoms, which are a general source for the sympathetic cooling of molecules, are loaded in the trap by quenching them from a cloud of laser-cooled metastable argon atoms. Although the ground state atoms cannot be directly probed, we detect them by observing the collisional loss of co-trapped metastable argon atoms using a new type of parametric loss spectroscopy. Using this technique we als...

  10. Effect of eccentricity on searches for gravitational waves from coalescing compact binaries in ground-based detectors

    International Nuclear Information System (INIS)

    Brown, Duncan A.; Zimmerman, Peter J.

    2010-01-01

    Inspiralling compact binaries are expected to circularize before their gravitational-wave signals reach the sensitive frequency band of ground-based detectors. Current searches for gravitational waves from compact binaries using the LIGO and Virgo detectors therefore use circular templates to construct matched filters. Binary formation models have been proposed which suggest that some systems detectable by the LIGO-Virgo network may have non-negligible eccentricity. We investigate the ability of the restricted 3.5 post-Newtonian order TaylorF2 template bank, used by LIGO and Virgo to search for gravitational waves from compact binaries with masses M≤35M · , to detect binaries with nonzero eccentricity. We model the gravitational waves from eccentric binaries using the x-model post-Newtonian formalism proposed by Hinder et al.[I. Hinder, F. Hermann, P. Laguna, and D. Shoemaker, arXiv:0806.1037v1]. We find that small residual eccentricities (e 0 · · . For eccentricities e 0 > or approx. 0.1, the loss in matched filter signal-to-noise ratio due to eccentricity can be significant and so templates which include eccentric effects will be required to perform optimal searches for such systems.

  11. Inter-annual variations in wave characteristics off Ratnagiri, Northeast Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Johnson, G.; SanilKumar, V.; Singh, J.

    location off the central west coast of India during 2008 to 2010 is negligible. The studies based on satellite derived data and ERA-Interim data have indicated that the significant wave height is marginally increasing in the south Indian Ocean and Arabian... for the monsoon period is the same (~ 2 m) in different years. Similarly the variation in annual average Hs during 2010 to 2013 is negligible (< 0.1 m). The average Hs during the monsoon is around 3 times that in the non-monsoon period and ~ 2 times...

  12. Relationship between ultrasonic Rayleigh waves and surface residual stress

    International Nuclear Information System (INIS)

    Adler, L.; Cook, K.V.; Dewey, B.R.; King, R.T.

    1977-01-01

    Local variations of Rayleigh (surface) circumferential ultrasonic wave velocity near a pipe-girth weld in large-diameter thin-wall type 316H stainless steel pipe were measured. The weldment was similar to those anticipated for the Liquid Metal Fast Breeder Reactor (LMFBR) piping systems. The residual stress distribution was estimated independently from shell theory for an elastic, infinite, thin shell with circumferential line loading. An upper bound on the magnitude of the residual stresses was estimated assuming the deformation of the shell was entirely elastic. The pattern of surface wave velocity variations matches the theoretical residual stress pattern closely. It is suggested that the monitoring of surface wave velocity variations might be used for characterizing residual stress patterns near critical welds in piping, aiding in design calculations, and for in-service monitoring of the state of stress of weldments

  13. Guidelines for ground motion definition for the eastern United States

    International Nuclear Information System (INIS)

    Gwaltney, R.C.; Aramayo, G.A.; Williams, R.T.

    1985-06-01

    Guidelines for the determination of earthquake ground motion definition for the eastern United States are established here. Both far-field and near-field guidelines are given. The guidelines were based on an extensive review of the current procedures for specifying ground motion in the United States. Both empirical and theoretical procedures were used in establishing the guidelines because of the low seismicity in the eastern United States. Only a few large- to great-sized earthquakes (M/sub s/ > 7.5) have occurred in this region, no evidence of tectonic surface ruptures related to historic or Holocene earthquakes has been found, and no currently active plate boundaries of any kind are known in this region. Very little instrumented data have been gathered in the East. Theoretical procedures are proposed so that in regions of almost no data, a reasonable level of seismic ground motion activity can be assumed. The guidelines are to be used to develop the safe shutdown earthquake (SSE). A new procedure for establishing the operating basis earthquake (OBE) is proposed, in particular for the eastern United States. The OBE would be developed using a probabilistic assessment of the geological conditions and the recurrence of seismic events at a site. These guidelines should be useful in development of seismic design requirements for future reactors. 17 refs., figs., tabs

  14. Dispersion-Engineered Traveling Wave Kinetic Inductance Parametric Amplifier

    Science.gov (United States)

    Zmuidzinas, Jonas (Inventor); Day, Peter K. (Inventor)

    2014-01-01

    A traveling wave kinetic inductance parametric amplifier comprises a superconducting transmission line and a dispersion control element. The transmission line can include periodic variations of its dimension along its length. The superconducting material can include a high normal state resistivity material. In some instances the high normal state resistivity material includes nitrogen and a metal selected from the group consisting of titanium, niobium and vanadium. The traveling wave kinetic inductance parametric amplifier is expected to exhibit a noise temperature below 100 mK/GHz.

  15. A Grounded Theory of Adolescent High School Women's Choir Singers' Process of Social Identity Development

    Science.gov (United States)

    Parker, Elizabeth Cassidy

    2018-01-01

    The purpose of this grounded theory study was to discover the process of social identity development for adolescent high school women's choir participants. Purposive maximum variation sampling was used to identify three public high school women's choirs where 54 interviews were conducted with 40 different public school singers. Three waves of data…

  16. Pump-dump iterative squeezing of vibrational wave packets.

    Science.gov (United States)

    Chang, Bo Y; Sola, Ignacio R

    2005-12-22

    The free motion of a nonstationary vibrational wave packet in an electronic potential is a source of interesting quantum properties. In this work we propose an iterative scheme that allows continuous stretching and squeezing of a wave packet in the ground or in an excited electronic state, by switching the wave function between both potentials with pi pulses at certain times. Using a simple model of displaced harmonic oscillators and delta pulses, we derive the analytical solution and the conditions for its possible implementation and optimization in different molecules and electronic states. We show that the main constraining parameter is the pulse bandwidth. Although in principle the degree of squeezing (or stretching) is not bounded, the physical resources increase quadratically with the number of iterations, while the achieved squeezing only increases linearly.

  17. Construction and study of exact ground states for a class of quantum antiferromagnets

    International Nuclear Information System (INIS)

    Fannes, M.

    1989-01-01

    Techniques of quantum probability are used to construct the exact ground states for a class of quantum spin systems in one dimension. This class in particular contains the antiferromagnetic models introduced by various authors under the name of VBS-models. The construction permits a detailed study of these ground states. (A.C.A.S.) [pt

  18. Ground state properties of the bond alternating spin-1/2 anisotropic Heisenberg chain

    Directory of Open Access Journals (Sweden)

    S. Paul

    2017-06-01

    Full Text Available Ground state properties, dispersion relations and scaling behaviour of spin gap of a bond alternating spin-1/2 anisotropic Heisenberg chain have been studied where the exchange interactions on alternate bonds are ferromagnetic (FM and antiferromagnetic (AFM in two separate cases. The resulting models separately represent nearest neighbour (NN AFM-AFM and AFM-FM bond alternating chains. Ground state energy has been estimated analytically by using both bond operator and Jordan-Wigner representations and numerically by using exact diagonalization. Dispersion relations, spin gap and several ground state orders have been obtained. Dimer order and string orders are found to coexist in the ground state. Spin gap is found to develop as soon as the non-uniformity in alternating bond strength is introduced in the AFM-AFM chain which further remains non-zero for the AFM-FM chain. This spin gap along with the string orders attribute to the Haldane phase. The Haldane phase is found to exist in most of the anisotropic region similar to the isotropic point.

  19. Dynamic Electron Correlation Effects on the Ground State Potential Energy Surface of a Retinal Chromophore Model.

    Science.gov (United States)

    Gozem, Samer; Huntress, Mark; Schapiro, Igor; Lindh, Roland; Granovsky, Alexander A; Angeli, Celestino; Olivucci, Massimo

    2012-11-13

    The ground state potential energy surface of the retinal chromophore of visual pigments (e.g., bovine rhodopsin) features a low-lying conical intersection surrounded by regions with variable charge-transfer and diradical electronic structures. This implies that dynamic electron correlation may have a large effect on the shape of the force fields driving its reactivity. To investigate this effect, we focus on mapping the potential energy for three paths located along the ground state CASSCF potential energy surface of the penta-2,4-dieniminium cation taken as a minimal model of the retinal chromophore. The first path spans the bond length alternation coordinate and intercepts a conical intersection point. The other two are minimum energy paths along two distinct but kinetically competitive thermal isomerization coordinates. We show that the effect of introducing the missing dynamic electron correlation variationally (with MRCISD) and perturbatively (with the CASPT2, NEVPT2, and XMCQDPT2 methods) leads, invariably, to a stabilization of the regions with charge transfer character and to a significant reshaping of the reference CASSCF potential energy surface and suggesting a change in the dominating isomerization mechanism. The possible impact of such a correction on the photoisomerization of the retinal chromophore is discussed.

  20. Modification of AMD wave functions and application to the breaking of the N=20 magic number

    International Nuclear Information System (INIS)

    Kimura, Masaaki; Horiuchi, Hisashi

    2001-01-01

    By using the deformed Gaussian instead of the spherical one, we have modified the AMD (Antisymmetrized Molecular Dynamics) wave functions. The calculation results with this modified AMD shows the drastic improvement of the deformation properties of Mg isotopes. This improvement means that this new version of AMD can treat the deformation of mean field properly than before and the deformation of mean field is important in Mg isotopes. With this new version of AMD, we have also calculated 32Mg in which the breaking of magic number N=20 is experimentally known. In this nucleus, β-energy surface is also drastically changed by the modification AMD wave function. Our results show that this nucleus is indeed deformed and neutron's 2p2h state is dominant in its ground state. This ground state reproduces the experimental data and shows the breaking of the magic number N=20 clearly. Additionally, near the ground state, there is also very interesting state which has neutron's 4p4h structure and shows parity violating density distribution and cluster-like nature. (author)

  1. Modification of AMD wave functions and application to the breaking of the N=20 magic number

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Masaaki; Horiuchi, Hisashi [Kyoto Univ. (Japan). Dept. of Physics

    2001-09-01

    By using the deformed Gaussian instead of the spherical one, we have modified the AMD (Antisymmetrized Molecular Dynamics) wave functions. The calculation results with this modified AMD shows the drastic improvement of the deformation properties of Mg isotopes. This improvement means that this new version of AMD can treat the deformation of mean field properly than before and the deformation of mean field is important in Mg isotopes. With this new version of AMD, we have also calculated 32Mg in which the breaking of magic number N=20 is experimentally known. In this nucleus, {beta}-energy surface is also drastically changed by the modification AMD wave function. Our results show that this nucleus is indeed deformed and neutron's 2p2h state is dominant in its ground state. This ground state reproduces the experimental data and shows the breaking of the magic number N=20 clearly. Additionally, near the ground state, there is also very interesting state which has neutron's 4p4h structure and shows parity violating density distribution and cluster-like nature. (author)

  2. Wind-waves interactions in the Gulf of Eilat

    Science.gov (United States)

    Shani-Zerbib, Almog; Liberzon, Dan; T-SAIL Team

    2017-11-01

    The Gulf of Eilat, at the southern tip of Israel, with its elongated rectangular shape and unique diurnal wind pattern is an appealing location for wind-waves interactions research. Results of experimental work will be reported analyzing a continuous, 50 hour long, data. Using a combined array of wind and waves sensing instruments, the wave field statistics and its response to variations of wind forcing were investigated. Correlations between diurnal fluctuations in wind magnitude and direction and the wave field response will be discussed. The directional spread of waves' energy, as estimated by the Wavelet Directional Method, showed a strong response to small variations in wind flow direction attributed to the unique topography of the gulf surroundings and its bathymetry. Influenced by relatively strong winds during the light hours, the wave field was dominated by a significant amount of breakings that are well pronounced in the saturation range of waves spectra. Temporal growth and decay behavior of the waves during the morning and evening wind transition periods was examined. Sea state induced roughness, as experienced by the wind flow turbulent boundary layer, is examined in view of the critical layer theory. Israel Science Foundation Grant # 1521/15.

  3. Temporal and Spatial Variation in, and Population Exposure to, Summertime Ground-Level Ozone in Beijing.

    Science.gov (United States)

    Zhao, Hui; Zheng, Youfei; Li, Ting; Wei, Li; Guan, Qing

    2018-03-29

    Ground-level ozone pollution in Beijing has been causing concern among the public due to the risks posed to human health. This study analyzed the temporal and spatial distribution of, and investigated population exposure to, ground-level ozone. We analyzed hourly ground-level ozone data from 35 ambient air quality monitoring sites, including urban, suburban, background, and traffic monitoring sites, during the summer in Beijing from 2014 to 2017. The results showed that the four-year mean ozone concentrations for urban, suburban, background, and traffic monitoring sites were 95.1, 99.8, 95.9, and 74.2 μg/m³, respectively. A total of 44, 43, 45, and 43 days exceeded the Chinese National Ambient Air Quality Standards (NAAQS) threshold for ground-level ozone in 2014, 2015, 2016, and 2017, respectively. The mean ozone concentration was higher in suburban sites than in urban sites, and the traffic monitoring sites had the lowest concentration. The diurnal variation in ground-level ozone concentration at the four types of monitoring sites displayed a single-peak curve. The peak and valley values occurred at 3:00-4:00 p.m. and 7:00 a.m., respectively. Spatially, ground-level ozone concentrations decreased in gradient from the north to the south. Population exposure levels were calculated based on ground-level ozone concentrations and population data. Approximately 50.38%, 44.85%, and 48.49% of the total population of Beijing were exposed to ground-level ozone concentrations exceeding the Chinese NAAQS threshold in 2014, 2015, and 2016, respectively.

  4. Temporal and Spatial Variation in, and Population Exposure to, Summertime Ground-Level Ozone in Beijing

    Science.gov (United States)

    Zheng, Youfei; Li, Ting; Wei, Li; Guan, Qing

    2018-01-01

    Ground-level ozone pollution in Beijing has been causing concern among the public due to the risks posed to human health. This study analyzed the temporal and spatial distribution of, and investigated population exposure to, ground-level ozone. We analyzed hourly ground-level ozone data from 35 ambient air quality monitoring sites, including urban, suburban, background, and traffic monitoring sites, during the summer in Beijing from 2014 to 2017. The results showed that the four-year mean ozone concentrations for urban, suburban, background, and traffic monitoring sites were 95.1, 99.8, 95.9, and 74.2 μg/m3, respectively. A total of 44, 43, 45, and 43 days exceeded the Chinese National Ambient Air Quality Standards (NAAQS) threshold for ground-level ozone in 2014, 2015, 2016, and 2017, respectively. The mean ozone concentration was higher in suburban sites than in urban sites, and the traffic monitoring sites had the lowest concentration. The diurnal variation in ground-level ozone concentration at the four types of monitoring sites displayed a single-peak curve. The peak and valley values occurred at 3:00–4:00 p.m. and 7:00 a.m., respectively. Spatially, ground-level ozone concentrations decreased in gradient from the north to the south. Population exposure levels were calculated based on ground-level ozone concentrations and population data. Approximately 50.38%, 44.85%, and 48.49% of the total population of Beijing were exposed to ground-level ozone concentrations exceeding the Chinese NAAQS threshold in 2014, 2015, and 2016, respectively. PMID:29596366

  5. Temporal and Spatial Variation in, and Population Exposure to, Summertime Ground-Level Ozone in Beijing

    Directory of Open Access Journals (Sweden)

    Hui Zhao

    2018-03-01

    Full Text Available Ground-level ozone pollution in Beijing has been causing concern among the public due to the risks posed to human health. This study analyzed the temporal and spatial distribution of, and investigated population exposure to, ground-level ozone. We analyzed hourly ground-level ozone data from 35 ambient air quality monitoring sites, including urban, suburban, background, and traffic monitoring sites, during the summer in Beijing from 2014 to 2017. The results showed that the four-year mean ozone concentrations for urban, suburban, background, and traffic monitoring sites were 95.1, 99.8, 95.9, and 74.2 μg/m3, respectively. A total of 44, 43, 45, and 43 days exceeded the Chinese National Ambient Air Quality Standards (NAAQS threshold for ground-level ozone in 2014, 2015, 2016, and 2017, respectively. The mean ozone concentration was higher in suburban sites than in urban sites, and the traffic monitoring sites had the lowest concentration. The diurnal variation in ground-level ozone concentration at the four types of monitoring sites displayed a single-peak curve. The peak and valley values occurred at 3:00–4:00 p.m. and 7:00 a.m., respectively. Spatially, ground-level ozone concentrations decreased in gradient from the north to the south. Population exposure levels were calculated based on ground-level ozone concentrations and population data. Approximately 50.38%, 44.85%, and 48.49% of the total population of Beijing were exposed to ground-level ozone concentrations exceeding the Chinese NAAQS threshold in 2014, 2015, and 2016, respectively.

  6. Investigation for Strong Ground Shaking across the Taipei Basin during the MW 7.0 Eastern Taiwan Offshore Earthquake of 31 March 2002

    Directory of Open Access Journals (Sweden)

    Yi-Ling Huang

    2010-01-01

    Full Text Available According to reconstructed ground motion snapshots of the northern Taiwan area during the MW 7.0 eastern Taiwan offshore earthquake of 31 March 2002, the composite effects indicated complicated wave propagation behavior in the ground motion of the Taipei basin. A major low frequency pulse arose after the S-wave with the duration of about 20 seconds was observed in northern Taiwan and dominated the radial direction. Observed waveforms of a low frequency pulse show amplification during the seismic wave across the Taipei basin from its eastern edge to western portion. This effect has been considered to be generated by an unusual source radiation, deep Moho reflection or basin bottom surface. In this study, recorded ground motions from a dense seismic network were analyzed using a frequency-wavenumber spectrum analysis for seismic wave propagation properties. We investigated temporal and spatial variations in strong shaking in different frequency bands. Results show that a simple pulse incident seismic wave strongly interacts with inside soft sediments and the surrounding topography of the Taipei basin which in turn extends its shaking duration. Evidence showed that seismic waves have been reflected back from its western boundary of basin with a dominant frequency near one Hz. Findings in this study have been rarely reported and may provide useful information to further constrain a three-dimensional numerical simulation for the basin response and velocity structure, and to predict ground motions of further large earthquakes.

  7. Induced quadrupolar singlet ground state of praseodymium in a modulated pyrochlore

    Science.gov (United States)

    van Duijn, J.; Kim, K. H.; Hur, N.; Ruiz-Bustos, R.; Adroja, D. T.; Bridges, F.; Daoud-Aladine, A.; Fernandez-Alonso, F.; Wen, J. J.; Kearney, V.; Huang, Q. Z.; Cheong, S.-W.; Perring, T. G.; Broholm, C.

    2017-09-01

    The complex structure and magnetism of Pr2 -xBixRu2O7 was investigated by neutron scattering and extended x-ray absorption fine structure. Pr has an approximate doublet ground state and the first excited state is a singlet. While the B -site (Ru) is well ordered throughout, this is not the case for the A -site (Pr/Bi). A broadened distribution for the Pr-O2 bond length at low temperature indicates the Pr environment varies from site to site even for x =0 . The environment about the Bi site is highly disordered ostensibly due to the 6 s lone pairs on Bi3 +. Correspondingly, we find that the non-Kramers doublet ground-state degeneracy, otherwise anticipated for Pr in the pyrochlore structure, is lifted so as to produce a quadrupolar singlet ground state with a spatially varying energy gap. For x =0 , below TN, the Ru sublattice orders antiferromagnetically, with propagation vector k =(0 ,0 ,0 ) as for Y2Ru2O7 . No ordering associated with the Pr sublattice is observed down to 100 mK. The low-energy magnetic response of Pr2 -xBixRu2O7 features a broad spectrum of magnetic excitations associated with inhomogeneous splitting of the Pr quasidoublet ground state. For x =0 (x =0.97 ), the spectrum is temperature dependent (independent). It appears disorder associated with Bi alloying enhances the inhomogeneous Pr crystal-field level splitting so that intersite interactions become irrelevant for x =0.97 . The structural complexity for the A -site may be reflected in the hysteretic uniform magnetization of B -site ruthenium in the Néel phase.

  8. Exact ground-state phase diagrams for the spin-3/2 Blume-Emery-Griffiths model

    Energy Technology Data Exchange (ETDEWEB)

    Canko, Osman; Keskin, Mustafa [Department of Physics, Erciyes University, 38039 Kayseri (Turkey); Deviren, Bayram [Institute of Science, Erciyes University, 38039 Kayseri (Turkey)], E-mail: keskin@erciyes.edu.tr

    2008-05-15

    We have calculated the exact ground-state phase diagrams of the spin-3/2 Ising model using the method that was proposed and applied to the spin-1 Ising model by Dublenych (2005 Phys. Rev. B 71 012411). The calculated, exact ground-state phase diagrams on the diatomic and triangular lattices with the nearest-neighbor (NN) interaction have been presented in this paper. We have obtained seven and 15 topologically different ground-state phase diagrams for J>0 and J<0, respectively, on the diatomic lattice and have found the conditions for the existence of uniform and intermediate or non-uniform phases. We have also constructed the exact ground-state phase diagrams of the model on the triangular lattice and found 20 and 59 fundamental phase diagrams for J>0 and J<0, respectively, the conditions for the existence of uniform and intermediate phases have also been found.

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

    International Nuclear Information System (INIS)

    Kyuregyan, A. S.

    2013-01-01

    The effect of band-to-band and trap-assisted tunneling on the properties of steady-state plane ionization waves in p + -n-n + 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 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 M . A comparison of the dependences u(E 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

  10. Phase control of electromagnetically induced acoustic wave transparency in a diamond nanomechanical resonator

    Energy Technology Data Exchange (ETDEWEB)

    Evangelou, Sofia, E-mail: Evangelousof@gmail.com

    2017-05-10

    Highlights: • A high-Q single-crystal diamond nanomechanical resonator embedded with nitrogen-vacancy (NV) centers is studied. • A Δ-type coupling configuration is formed. • The spin states of the ground state triplet of the NV centers interact with a strain field and two microwave fields. • The absorption and dispersion properties of the acoustic wave field are controlled by the use of the relative phase of the fields. • Phase-dependent acoustic wave absorption, transparency, and gain are obtained. • “Slow sound” and negative group velocities are also possible. - Abstract: We consider a high-Q single-crystal diamond nanomechanical resonator embedded with nitrogen-vacancy (NV) centers. We study the interaction of the transitions of the spin states of the ground state triplet of the NV centers with a strain field and two microwave fields in a Δ-type coupling configuration. We use the relative phase of the fields for the control of the absorption and dispersion properties of the acoustic wave field. Specifically, we show that by changing the relative phase of the fields, the acoustic field may exhibit absorption, transparency, gain and very interesting dispersive properties.

  11. Modeling continuous seismic velocity changes due to ground shaking in Chile

    Science.gov (United States)

    Gassenmeier, Martina; Richter, Tom; Sens-Schönfelder, Christoph; Korn, Michael; Tilmann, Frederik

    2015-04-01

    In order to investigate temporal seismic velocity changes due to earthquake related processes and environmental forcing, we analyze 8 years of ambient seismic noise recorded by the Integrated Plate Boundary Observatory Chile (IPOC) network in northern Chile between 18° and 25° S. The Mw 7.7 Tocopilla earthquake in 2007 and the Mw 8.1 Iquique earthquake in 2014 as well as numerous smaller events occurred in this area. By autocorrelation of the ambient seismic noise field, approximations of the Green's functions are retrieved. The recovered function represents backscattered or multiply scattered energy from the immediate neighborhood of the station. To detect relative changes of the seismic velocities we apply the stretching method, which compares individual autocorrelation functions to stretched or compressed versions of a long term averaged reference autocorrelation function. We use time windows in the coda of the autocorrelations, that contain scattered waves which are highly sensitive to minute changes in the velocity. At station PATCX we observe seasonal changes in seismic velocity as well as temporary velocity reductions in the frequency range of 4-6 Hz. The seasonal changes can be attributed to thermal stress changes in the subsurface related to variations of the atmospheric temperature. This effect can be modeled well by a sine curve and is subtracted for further analysis of short term variations. Temporary velocity reductions occur at the time of ground shaking usually caused by earthquakes and are followed by a recovery. We present an empirical model that describes the seismic velocity variations based on continuous observations of the local ground acceleration. Our hypothesis is that not only the shaking of earthquakes provokes velocity drops, but any small vibrations continuously induce minor velocity variations that are immediately compensated by healing in the steady state. We show that the shaking effect is accumulated over time and best described by

  12. Ground-state correlations within a nonperturbative approach

    Czech Academy of Sciences Publication Activity Database

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

    2017-01-01

    Roč. 95, č. 2 (2017), č. článku 024306. ISSN 2469-9985 R&D Projects: GA ČR GA13-07117S Institutional support: RVO:61389005 Keywords : ground state * harmonic oscillator frequency * space dimensions Subject RIV: BE - Theoretical Physics OBOR OECD: Atomic, molecular and chemical physics (physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect) Impact factor: 3.820, year: 2016

  13. Hadronic wave functions and high momentum transfer interactions in quantum chromodynamics

    International Nuclear Information System (INIS)

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

    1983-01-01

    This chapter emphasizes the utility of a Fock state representation of the meson and baryon wave functions as a means not only to parametrize the effects of bound state dynamics in QCD phenomena, but also to interrelate exclusive, inclusive, and higher twist processes. Discusses hadronic wave functions in QCD, measures of hadronic wave functions (form factors of composite systems, form factors of mesons, the meson distribution amplitude); large momentum transfer exclusive processes (two-photon processes); deep inelastic lepton scattering; and the phenomenology of hadronic wave functions (measures of hadron wave functions, constraints on the pion and proton valence wave function, quark jet diffraction excitation, the ''unveiling'' of the hadronic wave function and intrinsic charm). Finds that the testing ground of perturbative QCD where rigorous, definitive tests of the theory can be made can now be extended throughout a large domain of large momentum transfer exclusive and inclusive lepton, photon, and hadron reactions

  14. Chain and ladder models with two-body interactions and analytical ground states

    Science.gov (United States)

    Manna, Sourav; Nielsen, Anne E. B.

    2018-05-01

    We consider a family of spin-1 /2 models with few-body, SU(2)-invariant Hamiltonians and analytical ground states related to the one-dimensional (1D) Haldane-Shastry wave function. The spins are placed on the surface of a cylinder, and the standard 1D Haldane-Shastry model is obtained by placing the spins with equal spacing in a circle around the cylinder. Here, we show that another interesting family of models with two-body exchange interactions is obtained if we instead place the spins along one or two lines parallel to the cylinder axis, giving rise to chain and ladder models, respectively. We can change the scale along the cylinder axis without changing the radius of the cylinder. This gives us a parameter that controls the ratio between the circumference of the cylinder and all other length scales in the system. We use Monte Carlo simulations and analytical investigations to study how this ratio affects the properties of the models. If the ratio is large, we find that the two legs of the ladder decouple into two chains that are in a critical phase with Haldane-Shastry-like properties. If the ratio is small, the wave function reduces to a product of singlets. In between, we find that the behavior of the correlations and the Renyi entropy depends on the distance considered. For small distances the behavior is critical, and for long distances the correlations decay exponentially and the entropy shows an area law behavior. The distance up to which there is critical behavior gets larger as the ratio increases.

  15. Exact ground-state phase diagrams for the spin-3/2 Blume-Emery-Griffiths model

    International Nuclear Information System (INIS)

    Canko, Osman; Keskin, Mustafa; Deviren, Bayram

    2008-01-01

    We have calculated the exact ground-state phase diagrams of the spin-3/2 Ising model using the method that was proposed and applied to the spin-1 Ising model by Dublenych (2005 Phys. Rev. B 71 012411). The calculated, exact ground-state phase diagrams on the diatomic and triangular lattices with the nearest-neighbor (NN) interaction have been presented in this paper. We have obtained seven and 15 topologically different ground-state phase diagrams for J>0 and J 0 and J<0, respectively, the conditions for the existence of uniform and intermediate phases have also been found

  16. Variational Monte Carlo calculations of few-body nuclei

    International Nuclear Information System (INIS)

    Wiringa, R.B.

    1986-01-01

    The variational Monte Carlo method is described. Results for the binding energies, density distributions, momentum distributions, and static longitudinal structure functions of the 3 H, 3 He, and 4 He ground states, and for the energies of the low-lying scattering states in 4 He are presented. 25 refs., 3 figs

  17. Faddeev wave function decomposition using bipolar harmonics

    International Nuclear Information System (INIS)

    Friar, J.L.; Tomusiak, E.L.; Gibson, B.F.; Payne, G.L.

    1981-01-01

    The standard partial wave (channel) representation for the Faddeev solution to the Schroedinger equation for the ground state of 3 nucleons is written in terms of functions which couple the interacting pair and spectator angular momenta to give S, P, and D waves. For each such coupling there are three terms, one for each of the three cyclic permutations of the nucleon coordinates. A series of spherical harmonic identities is developed which allows writing the Faddeev solution in terms of a basis set of 5 bipolar harmonics: 1 for S waves; 1 for P waves; and 3 for D waves. The choice of a D-wave basis is largely arbitrary, and specific choices correspond to the decomposition schemes of Derrick and Blatt, Sachs, Gibson and Schiff, and Bolsterli and Jezak. The bipolar harmonic form greatly simplifies applications which utilize the wave function, and we specifically discuss the isoscalar charge (or mass) density and the 3 He Coulomb energy

  18. How to parametrize an S-wave resonance and how to identify two-hadron composites

    International Nuclear Information System (INIS)

    Toernqvist, N.A.

    1995-01-01

    The question of how one can distinguish quark model states from two-hadron states near an S-wave threshold is discussed, and the usefulness of the running mass is emphasized as the meeting ground for experiment and theory and for defining resonance parameters

  19. Heavy quark fragmentation functions for D-wave quarkonium and charmed beauty mesons

    International Nuclear Information System (INIS)

    Cheung, K.; Yuan, T.C.

    1995-09-01

    At the large transverse momentum region, the production of heavy-heavy bound-states such as charmonium, bottomonium, and anti bc mesons in high energy e + e - and hadronic collisions is dominated by parton fragmentation. The authors calculate the heavy quark fragmentation functions into the D-wave quarkonium and anti bc mesons to leading order in the strong coupling constant and in the non-relativistic expansion. In the anti bc meson case, one set of its D-wave states is expected to lie below the open flavor threshold. The total fragmentation probability for a anti b antiquark to split into the D-wave anti bc mesons is about 2 x 10 -5 , which implies that only 2% of the total pseudo-scalar ground state B c comes from the cascades of these orbitally excited states

  20. A projection gradient method for computing ground state of spin-2 Bose–Einstein condensates

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hanquan, E-mail: hanquan.wang@gmail.com [School of Statistics and Mathematics, Yunnan University of Finance and Economics, Kunming, Yunnan Province, 650221 (China); Yunnan Tongchang Scientific Computing and Data Mining Research Center, Kunming, Yunnan Province, 650221 (China)

    2014-10-01

    In this paper, a projection gradient method is presented for computing ground state of spin-2 Bose–Einstein condensates (BEC). We first propose the general projection gradient method for solving energy functional minimization problem under multiple constraints, in which the energy functional takes real functions as independent variables. We next extend the method to solve a similar problem, where the energy functional now takes complex functions as independent variables. We finally employ the method into finding the ground state of spin-2 BEC. The key of our method is: by constructing continuous gradient flows (CGFs), the ground state of spin-2 BEC can be computed as the steady state solution of such CGFs. We discretized the CGFs by a conservative finite difference method along with a proper way to deal with the nonlinear terms. We show that the numerical discretization is normalization and magnetization conservative and energy diminishing. Numerical results of the ground state and their energy of spin-2 BEC are reported to demonstrate the effectiveness of the numerical method.