Meaning of the nuclear wave function
NASA Astrophysics Data System (ADS)
Terry, John D.; Miller, Gerald A.
2016-07-01
Background: The intense current experimental interest in studying the structure of the deuteron and using it to enable accurate studies of neutron structure motivate us to examine the four-dimensional space-time nature of the nuclear wave function and the various approximations used to reduce it to an object that depends only on three spatial variables. Purpose: The aim is to determine if the ability to understand and analyze measured experimental cross sections is compromised by making the reduction from four to three dimensions. Method: Simple, exactly calculable, covariant models of a bound-state wave-state wave function (a scalar boson made of two constituent-scalar bosons) with parameters chosen to represent a deuteron are used to investigate the accuracy of using different approximations to the nuclear wave function to compute the quasielastic scattering cross section. Four different versions of the wave function are defined (light-front-spectator, light-front, light-front with scaling, and nonrelativistic) and used to compute the cross sections as a function of how far off the mass shell (how virtual) is the struck constituent. Results: We show that making an exact calculation of the quasielastic scattering cross section involves using the light-front-spectator wave function. All of the other approaches fail to reproduce the model exact calculation if the value of Bjorken x differs from unity. The model is extended to consider an essential effect of spin to show that constituent nucleons cannot be treated as being on their mass shell even when taking the matrix element of a "good" current. Conclusions: Developing realistic light-front-spectator wave functions to meet the needs of current and planned experiments is a worthwhile activity.
Factorized molecular wave functions: Analysis of the nuclear factor
Lefebvre, R.
2015-06-07
The exact factorization of molecular wave functions leads to nuclear factors which should be nodeless functions. We reconsider the case of vibrational perturbations in a diatomic species, a situation usually treated by combining Born-Oppenheimer products. It was shown [R. Lefebvre, J. Chem. Phys. 142, 074106 (2015)] that it is possible to derive, from the solutions of coupled equations, the form of the factorized function. By increasing artificially the interstate coupling in the usual approach, the adiabatic regime can be reached, whereby the wave function can be reduced to a single product. The nuclear factor of this product is determined by the lowest of the two potentials obtained by diagonalization of the potential matrix. By comparison with the nuclear wave function of the factorized scheme, it is shown that by a simple rectification, an agreement is obtained between the modified nodeless function and that of the adiabatic scheme.
Spin-orbit decomposition of ab initio nuclear wave functions
NASA Astrophysics Data System (ADS)
Johnson, Calvin W.
2015-03-01
Although the modern shell-model picture of atomic nuclei is built from single-particle orbits with good total angular momentum j , leading to j -j coupling, decades ago phenomenological models suggested that a simpler picture for 0 p -shell nuclides can be realized via coupling of the total spin S and total orbital angular momentum L . I revisit this idea with large-basis, no-core shell-model calculations using modern ab initio two-body interactions and dissect the resulting wave functions into their component L - and S -components. Remarkably, there is broad agreement with calculations using the phenomenological Cohen-Kurath forces, despite a gap of nearly 50 years and six orders of magnitude in basis dimensions. I suggest that L -S decomposition may be a useful tool for analyzing ab initio wave functions of light nuclei, for example, in the case of rotational bands.
The adiabatic limit of the exact factorization of the electron-nuclear wave function
NASA Astrophysics Data System (ADS)
Eich, F. G.; Agostini, Federica
2016-08-01
We propose a procedure to analyze the relation between the exact factorization of the electron-nuclear wave function and the Born-Oppenheimer approximation. We define the adiabatic limit as the limit of infinite nuclear mass. To this end, we introduce a unit system that singles out the dependence on the electron-nuclear mass ratio of each term appearing in the equations of the exact factorization. We observe how non-adiabatic effects induced by the coupling to the nuclear motion affect electronic properties and we analyze the leading term, connecting it to the classical nuclear momentum. Its dependence on the mass ratio is tested numerically on a model of proton-coupled electron transfer in different non-adiabatic regimes.
The adiabatic limit of the exact factorization of the electron-nuclear wave function.
Eich, F G; Agostini, Federica
2016-08-01
We propose a procedure to analyze the relation between the exact factorization of the electron-nuclear wave function and the Born-Oppenheimer approximation. We define the adiabatic limit as the limit of infinite nuclear mass. To this end, we introduce a unit system that singles out the dependence on the electron-nuclear mass ratio of each term appearing in the equations of the exact factorization. We observe how non-adiabatic effects induced by the coupling to the nuclear motion affect electronic properties and we analyze the leading term, connecting it to the classical nuclear momentum. Its dependence on the mass ratio is tested numerically on a model of proton-coupled electron transfer in different non-adiabatic regimes. PMID:27497542
Short range structure of hadron and nuclear wave functions at high x
Hoyer, P.; Brodsky, S.J.
1990-11-01
We discuss the short-range structure of hadronic and nuclear wave functions expected in QCD. In addition to the extrinsic'' contributions associated with radiation from single partons, there is an intrinsic'' hardness of the high-mass fluctuations of the wave function due to the spatial overlap of two or more partons. We argue that intrinsically-hard partons, having large mass and/or large transverse momentum, will dominate in the region of large Feynman x{sub F}. Their rescattering in nuclear targets is expected to be larger than for extrinsically-hard partons, leading to a suppressed production cross section for hadrons scattering on heavy nuclei. Experimental evidence for this exists for open chars. J/{psi}, and {gamma} production at large x{sub F}. The effects of intrinsic hardness may be particularly striking in nuclear wave functions, where the overlap of partons belonging to different nucleons can give rise to cumulative (x > 1) phenomena. The data on backward cumulative particle production from nuclei supports the existence of an intrinsically-hard component in nuclear wave functions. Partons at large x{sub F} may also be associated with the enhanced subthreshold production of particles observed in hadron-nucleus and nucleus-nucleus collisions. We discuss the evidence for anomalies in the large angle pp {yields} pp cross section near the charm threshold. Arguments are presented that chromium states may bind to nuclei through the QCD Van der Waals force. This would lead to a striking signal in charm production near threshold. 49 refs., 7 figs.
NASA Astrophysics Data System (ADS)
Scherrer, Arne; Agostini, Federica; Sebastiani, Daniel; Gross, E. K. U.; Vuilleumier, Rodolphe
2015-08-01
The nuclear velocity perturbation theory (NVPT) for vibrational circular dichroism (VCD) is derived from the exact factorization of the electron-nuclear wave function. This new formalism offers an exact starting point to include correction terms to the Born-Oppenheimer (BO) form of the molecular wave function, similar to the complete-adiabatic approximation. The corrections depend on a small parameter that, in a classical treatment of the nuclei, is identified as the nuclear velocity. Apart from proposing a rigorous basis for the NVPT, we show that the rotational strengths, related to the intensity of the VCD signal, contain a new contribution beyond-BO that can be evaluated with the NVPT and that only arises when the exact factorization approach is employed. Numerical results are presented for chiral and non-chiral systems to test the validity of the approach.
Scherrer, Arne; Agostini, Federica; Gross, E. K. U.; Sebastiani, Daniel; Vuilleumier, Rodolphe
2015-08-21
The nuclear velocity perturbation theory (NVPT) for vibrational circular dichroism (VCD) is derived from the exact factorization of the electron-nuclear wave function. This new formalism offers an exact starting point to include correction terms to the Born-Oppenheimer (BO) form of the molecular wave function, similar to the complete-adiabatic approximation. The corrections depend on a small parameter that, in a classical treatment of the nuclei, is identified as the nuclear velocity. Apart from proposing a rigorous basis for the NVPT, we show that the rotational strengths, related to the intensity of the VCD signal, contain a new contribution beyond-BO that can be evaluated with the NVPT and that only arises when the exact factorization approach is employed. Numerical results are presented for chiral and non-chiral systems to test the validity of the approach.
NASA Astrophysics Data System (ADS)
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.
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. PMID:20136303
NASA Astrophysics Data System (ADS)
Mentink-Vigier, Frédéric; Binet, Laurent; Vignoles, Gerard; Gourier, Didier; Vezin, Hervé
2010-11-01
The hyperfine interactions of the unpaired electron with eight surrounding G69a and G71a nuclei in Ti-doped β-Ga2O3 were analyzed by electron paramagnetic resonance (EPR) and electron-nuclear double resonance (ENDOR) spectroscopies. They are dominated by strong isotropic hyperfine couplings due to a direct Fermi contact interaction with Ga nuclei in octahedral sites of rutile-type chains oriented along b axis, revealing a large anisotropic spatial extension of the electron wave function. Titanium in β-Ga2O3 is thus best described as a diffuse (Ti4+-e-) pair rather than as a localized Ti3+ . Both electron and G69a nuclear spin Rabi oscillations could be observed by pulsed EPR and pulsed ENDOR, respectively. The electron spin decoherence time is about 1μs (at 4 K) and an upper bound of 520μs (at 8 K) is estimated for the nuclear decoherence time. Thus, β-Ga2O3:Ti appears to be a potential spin-bus system for quantum information processing with a large nuclear spin quantum register.
Wave-function frozen-density embedding: Approximate analytical nuclear ground-state gradients.
Heuser, Johannes; Höfener, Sebastian
2016-05-01
We report the derivation of approximate analytical nuclear ground-state uncoupled frozen density embedding (FDEu) gradients for the resolution of identity (RI) variant of the second-order approximate coupled cluster singles and doubles (RICC2) as well as density functional theory (DFT), and an efficient implementation thereof in the KOALA program. In order to guarantee a computationally efficient treatment, those gradient terms are neglected which would require the exchange of orbital information. This approach allows for geometry optimizations of single molecules surrounded by numerous molecules with fixed nuclei at RICC2-in-RICC2, RICC2-in-DFT, and DFT-in-DFT FDE level of theory using a dispersion correction, required due to the DFT-based treatment of the interaction in FDE theory. Accuracy and applicability are assessed by the example of two case studies: (a) the Watson-Crick pair adenine-thymine, for which the optimized structures exhibit a maximum error of about 0.08 Å for our best scheme compared to supermolecular reference calculations, (b) carbon monoxide on a magnesium oxide surface model, for which the error amount up to 0.1 Å for our best scheme. Efficiency is demonstrated by successively including environment molecules and comparing to an optimized conventional supermolecular implementation, showing that the method is able to outperform conventional RICC2 schemes already with a rather small number of environment molecules, gaining significant speed up in computation time. PMID:26804310
Adaptive multiconfigurational wave functions
Evangelista, Francesco A.
2014-03-28
A method is suggested to build simple multiconfigurational wave functions specified uniquely by an energy cutoff Λ. These are constructed from a model space containing determinants with energy relative to that of the most stable determinant no greater than Λ. The resulting Λ-CI wave function is adaptive, being able to represent both single-reference and multireference electronic states. We also consider a more compact wave function parameterization (Λ+SD-CI), which is based on a small Λ-CI reference and adds a selection of all the singly and doubly excited determinants generated from it. We report two heuristic algorithms to build Λ-CI wave functions. The first is based on an approximate prescreening of the full configuration interaction space, while the second performs a breadth-first search coupled with pruning. The Λ-CI and Λ+SD-CI approaches are used to compute the dissociation curve of N{sub 2} and the potential energy curves for the first three singlet states of C{sub 2}. Special attention is paid to the issue of energy discontinuities caused by changes in the size of the Λ-CI wave function along the potential energy curve. This problem is shown to be solvable by smoothing the matrix elements of the Hamiltonian. Our last example, involving the Cu{sub 2}O{sub 2}{sup 2+} core, illustrates an alternative use of the Λ-CI method: as a tool to both estimate the multireference character of a wave function and to create a compact model space to be used in subsequent high-level multireference coupled cluster computations.
Kowalewski, Markus Mukamel, Shaul
2015-07-28
Femtosecond Stimulated Raman Spectroscopy (FSRS) signals that monitor the excited state conical intersections dynamics of acrolein are simulated. An effective time dependent Hamiltonian for two C—H vibrational marker bands is constructed on the fly using a local mode expansion combined with a semi-classical surface hopping simulation protocol. The signals are obtained by a direct forward and backward propagation of the vibrational wave function on a numerical grid. Earlier work is extended to fully incorporate the anharmonicities and intermode couplings.
NASA Astrophysics Data System (ADS)
Kowalewski, Markus; Mukamel, Shaul
2015-07-01
Femtosecond Stimulated Raman Spectroscopy (FSRS) signals that monitor the excited state conical intersections dynamics of acrolein are simulated. An effective time dependent Hamiltonian for two C—H vibrational marker bands is constructed on the fly using a local mode expansion combined with a semi-classical surface hopping simulation protocol. The signals are obtained by a direct forward and backward propagation of the vibrational wave function on a numerical grid. Earlier work is extended to fully incorporate the anharmonicities and intermode couplings.
Properties of resonance wave functions.
NASA Technical Reports Server (NTRS)
More, R. M.; Gerjuoy, E.
1973-01-01
Construction and study of resonance wave functions corresponding to poles of the Green's function for several illustrative models of theoretical interest. Resonance wave functions obtained from the Siegert and Kapur-Peierls definitions of the resonance energies are compared. The comparison especially clarifies the meaning of the normalization constant of the resonance wave functions. It is shown that the wave functions may be considered renormalized in a sense analogous to that of quantum field theory. However, this renormalization is entirely automatic, and the theory has neither ad hoc procedures nor infinite quantities.
Photoelectron wave function in photoionization: plane wave or Coulomb wave?
Gozem, Samer; Gunina, Anastasia O; Ichino, Takatoshi; Osborn, David L; Stanton, John F; Krylov, Anna I
2015-11-19
The calculation of absolute total cross sections requires accurate wave functions of the photoelectron and of the initial and final states of the system. The essential information contained in the latter two can be condensed into a Dyson orbital. We employ correlated Dyson orbitals and test approximate treatments of the photoelectron wave function, that is, plane and Coulomb waves, by comparing computed and experimental photoionization and photodetachment spectra. We find that in anions, a plane wave treatment of the photoelectron provides a good description of photodetachment spectra. For photoionization of neutral atoms or molecules with one heavy atom, the photoelectron wave function must be treated as a Coulomb wave to account for the interaction of the photoelectron with the +1 charge of the ionized core. For larger molecules, the best agreement with experiment is often achieved by using a Coulomb wave with a partial (effective) charge smaller than unity. This likely derives from the fact that the effective charge at the centroid of the Dyson orbital, which serves as the origin of the spherical wave expansion, is smaller than the total charge of a polyatomic cation. The results suggest that accurate molecular photoionization cross sections can be computed with a modified central potential model that accounts for the nonspherical charge distribution of the core by adjusting the charge in the center of the expansion. PMID:26509428
Evanescent Waves Nuclear Magnetic Resonance
Halidi, El Mohamed; Nativel, Eric; Akel, Mohamad; Kenouche, Samir; Coillot, Christophe; Alibert, Eric; Jabakhanji, Bilal; Schimpf, Remy; Zanca, Michel; Stein, Paul; Goze-Bac, Christophe
2016-01-01
Nuclear Magnetic Resonance spectroscopy and imaging can be classified as inductive techniques working in the near- to far-field regimes. We investigate an alternative capacitive detection with the use of micrometer sized probes positioned at sub wavelength distances of the sample in order to characterize and model evanescent electromagnetic fields originating from NMR phenomenon. We report that in this experimental configuration the available NMR signal is one order of magnitude larger and follows an exponential decay inversely proportional to the size of the emitters. Those investigations open a new road to a better understanding of the evanescent waves component in NMR with the opportunity to perform localized spectroscopy and imaging. PMID:26751800
Chasman, R.R.
1995-08-01
In the past few years, we developed many-body variational wave functions that allow one to treat pairing and particle-hole two-body interactions on an equal footing. The complexity of these wave functions depends on the number of levels included in the valence space, but does not depend on the number of nucleons in the system. By using residual interaction strengths (e.g. the quadrupole interaction strength or pairing interaction strength) as generator coordinates, one gets many different wave functions, each having a different expectation value for the relevant interaction mode. These wave functions are particularly useful when one is dealing with a situation in which the mean-field approximation is inadequate. Because the same basis states are used in the construction of the many-body wave functions, it is possible to calculate overlaps and interaction matrix elements for the many-body wave functions (which are not in general orthogonal) easily. The valence space can contain a large number of single-particle basis states, when there are constants of motion that can be used to break the levels up into groups. We added a cranking term to the many-body Hamiltonian and modified the projection procedure to get states of good signature before variation. In our present implementation, each group is limited to eight pairs of single-particle levels. We are working on ways of increasing the number of levels that can be included in each group. We are also working on including particle-particle residual interaction modes, in addition to pairing, in our Hamiltonian.
Nuclear Parton Distribution Functions
I. Schienbein, J.Y. Yu, C. Keppel, J.G. Morfin, F. Olness, J.F. Owens
2009-06-01
We study nuclear effects of charged current deep inelastic neutrino-iron scattering in the framework of a {chi}{sup 2} analysis of parton distribution functions (PDFs). We extract a set of iron PDFs which are used to compute x{sub Bj}-dependent and Q{sup 2}-dependent nuclear correction factors for iron structure functions which are required in global analyses of free nucleon PDFs. We compare our results with nuclear correction factors from neutrino-nucleus scattering models and correction factors for charged-lepton--iron scattering. We find that, except for very high x{sub Bj}, our correction factors differ in both shape and magnitude from the correction factors of the models and charged-lepton scattering.
Coulomb wave functions in momentum space
Eremenko, V; Upadhyay, N. J.; Thompson, I J; Elster, Charlotte; Nunes, F. M.; Arbanas, Goran; Escher, J.E.; Hlophe, L.
2015-01-01
An algorithm to calculate non-relativistic partial-wave Coulomb functions in momentum space is presented. The arguments are the Sommerfeld parameter eta, the angular momentum l, the asymptotic momentum q and the 'running' momentum p, where both momenta are real. Since the partial-wave Coulomb functions exhibit singular behavior when p -> q, different representations of the Legendre functions of the 2nd kind need to be implemented in computing the functions for the values of p close to the singularity and far away from it. The code for the momentum-space Coulomb wave functions is applicable for values of vertical bar eta vertical bar in the range of 10(-1) to 10, and thus is particularly suited for momentum space calculations of nuclear reactions. Program Summary Program title: libcwfn Catalogue identifier: AEUQ_v1_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEUQ_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 864503 No. of bytes in distributed program, including test data, etc.: 7178021 Distribution format: tar.gz Programming language: Fortran 90, Fortran 77, Python, make (GNU Make dialect), GNU Bash shell interpreter (available as /bin/bash). Computer: Apple Powermac (Intel Xeon), ASUS K53U (AMD E-350 (Dual Core)), DELL Precision T3500 (Intel Xeon), NERSC Carver (Intel Nehalem Quad Core). Operating system: Linux, Windows (using Cygwin). RAM: less than 512 Mbytes Classification: 17.8, 17.13, 17.16. Nature of problem: The calculation of partial wave Coulomb functions with integer land all other arguments real. Solution method: Computing the value of the function using explicit formulae and algorithms. Running time: Less than 10(-3) s. (C) 2014 Elsevier B.V. All rights reserved.
Coulomb wave functions in momentum space
Eremenko, V; Upadhyay, N. J.; Thompson, I J; Elster, Charlotte; Nunes, F. M.; Arbanas, Goran; Escher, J.E.; Hlophe, L.
2015-01-01
An algorithm to calculate non-relativistic partial-wave Coulomb functions in momentum space is presented. The arguments are the Sommerfeld parameter eta, the angular momentum l, the asymptotic momentum q and the 'running' momentum p, where both momenta are real. Since the partial-wave Coulomb functions exhibit singular behavior when p -> q, different representations of the Legendre functions of the 2nd kind need to be implemented in computing the functions for the values of p close to the singularity and far away from it. The code for the momentum-space Coulomb wave functions is applicable for values of vertical bar eta vertical barmore » in the range of 10(-1) to 10, and thus is particularly suited for momentum space calculations of nuclear reactions. Program Summary Program title: libcwfn Catalogue identifier: AEUQ_v1_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEUQ_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 864503 No. of bytes in distributed program, including test data, etc.: 7178021 Distribution format: tar.gz Programming language: Fortran 90, Fortran 77, Python, make (GNU Make dialect), GNU Bash shell interpreter (available as /bin/bash). Computer: Apple Powermac (Intel Xeon), ASUS K53U (AMD E-350 (Dual Core)), DELL Precision T3500 (Intel Xeon), NERSC Carver (Intel Nehalem Quad Core). Operating system: Linux, Windows (using Cygwin). RAM: less than 512 Mbytes Classification: 17.8, 17.13, 17.16. Nature of problem: The calculation of partial wave Coulomb functions with integer land all other arguments real. Solution method: Computing the value of the function using explicit formulae and algorithms. Running time: Less than 10(-3) s. (C) 2014 Elsevier B.V. All rights reserved.« less
Meson wave function from holographic approaches
Vega, Alfredo; Schmidt, Ivan; Branz, Tanja; Gutsche, Thomas; Lyubovitskij, Valery E.
2010-08-04
We discuss the light-front wave function for the valence quark state of mesons using the AdS/CFT correspondence. We consider two kinds of wave functions obtained in different holographic Soft-Wall approaches.
Adiabatic corrections to density functional theory energies and wave functions.
Mohallem, José R; Coura, Thiago de O; Diniz, Leonardo G; de Castro, Gustavo; Assafrão, Denise; Heine, Thomas
2008-09-25
The adiabatic finite-nuclear-mass-correction (FNMC) to the electronic energies and wave functions of atoms and molecules is formulated for density-functional theory and implemented in the deMon code. The approach is tested for a series of local and gradient corrected density functionals, using MP2 results and diagonal-Born-Oppenheimer corrections from the literature for comparison. In the evaluation of absolute energy corrections of nonorganic molecules the LDA PZ81 functional works surprisingly better than the others. For organic molecules the GGA BLYP functional has the best performance. FNMC with GGA functionals, mainly BLYP, show a good performance in the evaluation of relative corrections, except for nonorganic molecules containing H atoms. The PW86 functional stands out with the best evaluation of the barrier of linearity of H2O and the isotopic dipole moment of HDO. In general, DFT functionals display an accuracy superior than the common belief and because the corrections are based on a change of the electronic kinetic energy they are here ranked in a new appropriate way. The approach is applied to obtain the adiabatic correction for full atomization of alcanes C(n)H(2n+2), n = 4-10. The barrier of 1 mHartree is approached for adiabatic corrections, justifying its insertion into DFT. PMID:18537228
Mechanotransduction and nuclear function.
Graham, David M; Burridge, Keith
2016-06-01
Many signaling pathways converge on the nucleus to regulate crucial nuclear events such as transcription, DNA replication and cell cycle progression. Although the vast majority of research in this area has focused on signals generated in response to hormones or other soluble factors, the nucleus also responds to mechanical forces. During the past decade or so, much has been learned about how mechanical force can affect transcription, as well as the growth and differentiation of cells. Much has also been learned about how force is transmitted via the cytoskeleton to the nucleus and then across the nuclear envelope to the nuclear lamina and chromatin. In this brief review, we focus on some of the key proteins that transmit mechanical signals across the nuclear envelope. PMID:27018929
Meson wave function from holographic models
Vega, Alfredo; Schmidt, Ivan; Branz, Tanja; Gutsche, Thomas; Lyubovitskij, Valery E.
2009-09-01
We consider the light-front wave function for the valence quark state of mesons using the AdS/CFT correspondence, as has been suggested by Brodsky and Teramond. Two kinds of wave functions, obtained in different holographic Soft-Wall models, are discussed.
Chiral density wave in nuclear matter
NASA Astrophysics Data System (ADS)
Heinz, Achim; Giacosa, Francesco; Rischke, Dirk H.
2015-01-01
Inspired by recent work on inhomogeneous chiral condensation in cold, dense quark matter within models featuring quark degrees of freedom, we investigate the chiral density-wave solution in nuclear matter at zero temperature and nonvanishing baryon number density in the framework of the so-called extended linear sigma model (eLSM). The eLSM is an effective model for the strong interaction based on the global chiral symmetry of quantum chromodynamics (QCD). It contains scalar, pseudoscalar, vector, and axial-vector mesons as well as baryons. In the latter sector, the nucleon and its chiral partner are introduced as parity doublets in the mirror assignment. The eLSM simultaneously provides a good description of hadrons in vacuum as well as nuclear matter ground-state properties. We find that an inhomogeneous phase in the form of a chiral density wave is realized, but only for densities larger than 2.4ρ0, where ρ0 is the nuclear matter ground-state density.
Eskola, K.J.; Vogt, R.; Wang, X.N.
1995-07-01
A three parameter Wood-Saxon shape is used to describe the nuclear density distribution, which R{sub A} is the nuclear radius, {approx} is the surface thickness, and {omega} allows for central irregularities. The electron scattering data is used where available for R{sub A}, z, and {omega}. When data is unavailable, the parameters {omega} = O, z = 0.54 fm and R{sub A} = 1.19 A{sup 1/3} - 1.61 A{sup -1/3} fm are used. The central density {rho}{sub 0} is found from the normalization {infinity} d{sup 3}r{rho}{sub A}(r) = A.
Spatial wave functions of photon and electron
Khokhlov, D. L.
2010-12-01
The quantum mechanical model of the photon and electron is considered. The photon is conceived of as a particle moving with the speed of light which is accompanied by the wave function of the photon spreading out with an infinite speed. The wave function of the electron is introduced in terms of virtual photons tied to the electron. A description of electrostatic and magnetostatic interactions is given through the wave functions of electrons. The approach provides an explanation of the results of recent experiments measuring the speed of propagation of the bound magnetic field.
Reality and measurement of the wave function
NASA Astrophysics Data System (ADS)
Unruh, W. G.
1994-07-01
Using a simple version of the model for the quantum measurement of a two-level system, the contention of Aharonov, Anandan, and Vaidman [Phys. Rev. A 47, 4616 (1993)] that one must in certain circumstances give the wave function an ontological as well as an epistemological significance is examined. I decide that their argument that the wave function of a system can be measured on a single system fails to establish the key point and that what they demonstrate is the ontological significance of certain operators in the theory, with the wave function playing its usual epistemological role.
New approach to folding with the Coulomb wave function
Blokhintsev, L. D.; Savin, D. A.; Kadyrov, A. S.; Mukhamedzhanov, A. M.
2015-05-15
Due to the long-range character of the Coulomb interaction theoretical description of low-energy nuclear reactions with charged particles still remains a formidable task. One way of dealing with the problem in an integral-equation approach is to employ a screened Coulomb potential. A general approach without screening requires folding of kernels of the integral equations with the Coulomb wave. A new method of folding a function with the Coulomb partial waves is presented. The partial-wave Coulomb function both in the configuration and momentum representations is written in the form of separable series. Each term of the series is represented as a product of a factor depending only on the Coulomb parameter and a function depending on the spatial variable in the configuration space and the momentum variable if the momentum representation is used. Using a trial function, the method is demonstrated to be efficient and reliable.
Explicitly correlated wave function for a boron atom
NASA Astrophysics Data System (ADS)
Puchalski, Mariusz; Komasa, Jacek; Pachucki, Krzysztof
2015-12-01
We present results of high-precision calculations for a boron atom's properties using wave functions expanded in the explicitly correlated Gaussian basis. We demonstrate that the well-optimized 8192 basis functions enable a determination of energy levels, ionization potential, and fine and hyperfine splittings in atomic transitions with nearly parts per million precision. The results open a window to a spectroscopic determination of nuclear properties of boron including the charge radius of the proton halo in the 8B nucleus.
The geometry of electron wave functions
Aminov, Yurii A
2013-02-28
To each wave function we assign a codimension-two submanifold in Euclidean space. We study the case of the wave function of a single electron in the hydrogen atom or other hydrogen-type atoms with quantum numbers n, l, m in detail. We prove theorems describing the behaviour of the scalar and sectional curvature of the constructed submanifold, depending on the quantum numbers. We also consider the external geometry of the submanifold. Bibliography: 9 titles.
Functional evolution of nuclear structure
Dawson, Scott C.
2011-01-01
The evolution of the nucleus, the defining feature of eukaryotic cells, was long shrouded in speculation and mystery. There is now strong evidence that nuclear pore complexes (NPCs) and nuclear membranes coevolved with the endomembrane system, and that the last eukaryotic common ancestor (LECA) had fully functional NPCs. Recent studies have identified many components of the nuclear envelope in living Opisthokonts, the eukaryotic supergroup that includes fungi and metazoan animals. These components include diverse chromatin-binding membrane proteins, and membrane proteins with adhesive lumenal domains that may have contributed to the evolution of nuclear membrane architecture. Further discoveries about the nucleoskeleton suggest that the evolution of nuclear structure was tightly coupled to genome partitioning during mitosis. PMID:22006947
Weak measurement and Bohmian conditional wave functions
Norsen, Travis; Struyve, Ward
2014-11-15
It was recently pointed out and demonstrated experimentally by Lundeen et al. that the wave function of a particle (more precisely, the wave function possessed by each member of an ensemble of identically-prepared particles) can be “directly measured” using weak measurement. Here it is shown that if this same technique is applied, with appropriate post-selection, to one particle from a perhaps entangled multi-particle system, the result is precisely the so-called “conditional wave function” of Bohmian mechanics. Thus, a plausibly operationalist method for defining the wave function of a quantum mechanical sub-system corresponds to the natural definition of a sub-system wave function which Bohmian mechanics uniquely makes possible. Similarly, a weak-measurement-based procedure for directly measuring a sub-system’s density matrix should yield, under appropriate circumstances, the Bohmian “conditional density matrix” as opposed to the standard reduced density matrix. Experimental arrangements to demonstrate this behavior–and also thereby reveal the non-local dependence of sub-system state functions on distant interventions–are suggested and discussed. - Highlights: • We study a “direct measurement” protocol for wave functions and density matrices. • Weakly measured states of entangled particles correspond to Bohmian conditional states. • Novel method of observing quantum non-locality is proposed.
The Wave Function and Quantum Reality
Gao Shan
2011-03-28
We investigate the meaning of the wave function by analyzing the mass and charge density distributions of a quantum system. According to protective measurement, a charged quantum system has effective mass and charge density distributing in space, proportional to the square of the absolute value of its wave function. In a realistic interpretation, the wave function of a quantum system can be taken as a description of either a physical field or the ergodic motion of a particle. The essential difference between a field and the ergodic motion of a particle lies in the property of simultaneity; a field exists throughout space simultaneously, whereas the ergodic motion of a particle exists throughout space in a time-divided way. If the wave function is a physical field, then the mass and charge density will be distributed in space simultaneously for a charged quantum system, and thus there will exist gravitational and electrostatic self-interactions of its wave function. This not only violates the superposition principle of quantum mechanics but also contradicts experimental observations. Thus the wave function cannot be a description of a physical field but be a description of the ergodic motion of a particle. For the later there is only a localized particle with mass and charge at every instant, and thus there will not exist any self-interaction for the wave function. It is further argued that the classical ergodic models, which assume continuous motion of particles, cannot be consistent with quantum mechanics. Based on the negative result, we suggest that the wave function is a description of the quantum motion of particles, which is random and discontinuous in nature. On this interpretation, the square of the absolute value of the wave function not only gives the probability of the particle being found in certain locations, but also gives the probability of the particle being there. The suggested new interpretation of the wave function provides a natural realistic
The evolution of oscillator wave functions
NASA Astrophysics Data System (ADS)
Andrews, Mark
2016-04-01
We investigate how wave functions evolve with time in the harmonic oscillator. We first review the periodicity properties over each multiple of a quarter of the classical oscillation period. Then we show that any wave function can be simply transformed so that its centroid, defined by the expectation values of position and momentum, remains at rest at the center of the oscillator. This implies that we need only consider the evolution of this restricted class of wave functions; the evolution of all others can be reduced to these. The evolution of the spread in position Δx and momentum Δp throws light on energy and uncertainty and on squeezed and coherent states. Finally, we show that any wave function can be transformed so that Δx and Δp do not change with time and that the evolution of all wave functions can easily be found from the evolution of those at rest at the origin with unchanging Δx and Δp.
Plasmon wave function of graphene nanoribbons
NASA Astrophysics Data System (ADS)
Silveiro, I.; Plaza Ortega, J. M.; García de Abajo, F. J.
2015-08-01
We find the low-frequency optical response of highly doped individual and arrayed graphene nanoribbons to be accurately described in terms of plasmon wave functions (PWFs). More precisely, we focus on the lowest-order transverse dipolar mode, for which we define the wave function as the induced charge density associated with the plasmon. We show that a single universal wave function is capable of describing the normal-incidence interaction of paired, co-planar, and stacked arrays of ribbons down to small inter-ribbon distances. Our work provides both intuitive insight into graphene plasmon interactions and a practical way of accurately describing complex graphene geometries based on the PWFs of the individual components.
Spontaneous symmetry breaking in correlated wave functions
NASA Astrophysics Data System (ADS)
Kaneko, Ryui; Tocchio, Luca F.; Valentí, Roser; Becca, Federico; Gros, Claudius
2016-03-01
We show that Jastrow-Slater wave functions, in which a density-density Jastrow factor is applied onto an uncorrelated fermionic state, may possess long-range order even when all symmetries are preserved in the wave function. This fact is mainly related to the presence of a sufficiently strong Jastrow term (also including the case of full Gutzwiller projection, suitable for describing spin models). Selected examples are reported, including the spawning of Néel order and dimerization in spin systems, and the stabilization of charge and orbital order in itinerant electronic systems.
Nonlinear wave function expansions : a progress report.
Shepard, R.; Minkoff, M.; Brozell, S. R.; Chemistry
2007-12-01
Some recent progress is reported for a novel nonlinear expansion form for electronic wave functions. This expansion form is based on spin eigenfunctions using the Graphical Unitary Group Approach and the wave function is expanded in a basis of product functions, allowing application to closed and open shell systems and to ground and excited electronic states. Each product basis function is itself a multiconfigurational expansion that depends on a relatively small number of nonlinear parameters called arc factors. Efficient recursive procedures for the computation of reduced one- and two-particle density matrices, overlap matrix elements, and Hamiltonian matrix elements result in a very efficient computational procedure that is applicable to very large configuration state function (CSF) expansions. A new energy-based optimization approach is presented based on product function splitting and variational recombination. Convergence of both valence correlation energy and dynamical correlation energy with respect to the product function basis dimension is examined. A wave function analysis approach suitable for very large CSF expansions is presented based on Shavitt graph node density and arc density. Some new closed-form expressions for various Shavitt Graph and Auxiliary Pair Graph statistics are presented.
Multifractal wave functions of simple quantum maps
NASA Astrophysics Data System (ADS)
Martin, John; García-Mata, Ignacio; Giraud, Olivier; Georgeot, Bertrand
2010-10-01
We study numerically multifractal properties of two models of one-dimensional quantum maps: a map with pseudointegrable dynamics and intermediate spectral statistics and a map with an Anderson-like transition recently implemented with cold atoms. Using extensive numerical simulations, we compute the multifractal exponents of quantum wave functions and study their properties, with the help of two different numerical methods used for classical multifractal systems (box-counting and wavelet methods). We compare the results of the two methods over a wide range of values. We show that the wave functions of the Anderson map display a multifractal behavior similar to eigenfunctions of the three-dimensional Anderson transition but of a weaker type. Wave functions of the intermediate map share some common properties with eigenfunctions at the Anderson transition (two sets of multifractal exponents, with similar asymptotic behavior), but other properties are markedly different (large linear regime for multifractal exponents even for strong multifractality, different distributions of moments of wave functions, and absence of symmetry of the exponents). Our results thus indicate that the intermediate map presents original properties, different from certain characteristics of the Anderson transition derived from the nonlinear sigma model. We also discuss the importance of finite-size effects.
Constructibility of the Universal Wave Function
NASA Astrophysics Data System (ADS)
Bolotin, Arkady
2016-05-01
This paper focuses on a constructive treatment of the mathematical formalism of quantum theory and a possible role of constructivist philosophy in resolving the foundational problems of quantum mechanics, particularly, the controversy over the meaning of the wave function of the universe. As it is demonstrated in the paper, unless the number of the universe's degrees of freedom is fundamentally upper bounded (owing to some unknown physical laws) or hypercomputation is physically realizable, the universal wave function is a non-constructive entity in the sense of constructive recursive mathematics. This means that even if such a function might exist, basic mathematical operations on it would be undefinable and subsequently the only content one would be able to deduce from this function would be pure symbolical.
Millimeter wave detection of nuclear radiation - an alternative detection mechanism.
Gopalsami, N.; Chien, H. T.; Heifetz, A.; Koehl, E. R.; Raptis, A. C.; Nuclear Engineering Division
2009-08-01
We present a nuclear radiation detection mechanism using millimeter waves as an alternative to conventional detection. It is based on the concept that nuclear radiation causes ionization of air and that if we place a dielectric material near the radiation source, it acts as a charge accumulator of the air ions. We have found that millimeter waves can interrogate the charge cloud on the dielectric material remotely. This concept was tested with a standoff millimeter wave system by monitoring the charge levels on a cardboard tube placed in an x-ray beam.
Millimeter wave detection of nuclear radiation: An alternative detection mechanism
Gopalsami, N.; Chien, H. T.; Heifetz, A.; Koehl, E. R.; Raptis, A. C.
2009-08-15
We present a nuclear radiation detection mechanism using millimeter waves as an alternative to conventional detection. It is based on the concept that nuclear radiation causes ionization of air and that if we place a dielectric material near the radiation source, it acts as a charge accumulator of the air ions. We have found that millimeter waves can interrogate the charge cloud on the dielectric material remotely. This concept was tested with a standoff millimeter wave system by monitoring the charge levels on a cardboard tube placed in an x-ray beam.
Millimeter wave detection of nuclear radiation: an alternative detection mechanism.
Gopalsami, N; Chien, H T; Heifetz, A; Koehl, E R; Raptis, A C
2009-08-01
We present a nuclear radiation detection mechanism using millimeter waves as an alternative to conventional detection. It is based on the concept that nuclear radiation causes ionization of air and that if we place a dielectric material near the radiation source, it acts as a charge accumulator of the air ions. We have found that millimeter waves can interrogate the charge cloud on the dielectric material remotely. This concept was tested with a standoff millimeter wave system by monitoring the charge levels on a cardboard tube placed in an x-ray beam. PMID:19725673
Millimeter wave detection of nuclear radiation: An alternative detection mechanism
NASA Astrophysics Data System (ADS)
Gopalsami, N.; Chien, H. T.; Heifetz, A.; Koehl, E. R.; Raptis, A. C.
2009-08-01
We present a nuclear radiation detection mechanism using millimeter waves as an alternative to conventional detection. It is based on the concept that nuclear radiation causes ionization of air and that if we place a dielectric material near the radiation source, it acts as a charge accumulator of the air ions. We have found that millimeter waves can interrogate the charge cloud on the dielectric material remotely. This concept was tested with a standoff millimeter wave system by monitoring the charge levels on a cardboard tube placed in an x-ray beam.
General Forms of Wave Functions for Dipositronium, Ps2
NASA Technical Reports Server (NTRS)
Schrader, D.M.
2007-01-01
The consequences of particle interchange symmetry for the structure of wave functions of the states of dipositronium was recently discussed by the author [I]. In the present work, the methodology is simply explained, and the wave functions are explicitly given.
NASA Astrophysics Data System (ADS)
Douglas, A.; Marshall, P. D.; Young, J. B.
1993-06-01
The t* (the ratio of the travel time to the specific quality factor) estimates of Chun et al. (1991) for P waves for paths from several test sites to the Yellowknife array (YKA) are argued to be strongly dependent on the assumptions made about the source; there is little evidence that the source models of explosions derived from close-in observations yield reliable predictions of the source pulse radiated to long range. With frequency domain methods the confidence limits on the rate of falloff of source-corrected explosion spectra may be low and give the impression that the t* estimates are well constrained. However, because of the uncertainties in the source spectra the confidence limits must be underestimates of the true values. In their reply Chun et al. argue that that their t* estimates are higher than the published single-window values. A proper determination of the frequency dependence of t* requires, among other things, elucidation of the role of scattering attenuation.
Covariance Constraints for Light Front Wave Functions
NASA Astrophysics Data System (ADS)
Müller, D.
2016-06-01
Light front wave functions (LFWFs) are often utilized to model parton distributions and form factors where their transverse and longitudinal momenta are tied to each other in some manner that is often guided by convenience. On the other hand, the cross talk of transverse and longitudinal momenta is governed by Poincaré symmetry and thus popular LFWF models are often not usable to model more intricate quantities such as generalized parton distributions. In this contribution a closer look to this issue is given and it is shown how to overcome the issue for two-body LFWFs.
Lanczos steps to improve variational wave functions
NASA Astrophysics Data System (ADS)
Becca, Federico; Hu, Wen-Jun; Iqbal, Yasir; Parola, Alberto; Poilblanc, Didier; Sorella, Sandro
2015-09-01
Gutzwiller-projected fermionic states can be efficiently implemented within quantum Monte Carlo calculations to define extremely accurate variational wave functions for Heisenberg models on frustrated two-dimensional lattices, not only for the ground state but also for low-energy excitations. The application of few Lanczos steps on top of these states further improves their accuracy, allowing calculations on large clusters. In addition, by computing both the energy and its variance, it is possible to obtain reliable estimations of exact results. Here, we report the cases of the frustrated Heisenberg models on square and Kagome lattices.
Variational wave functions for homogenous Bose systems
Sueto, Andras; Szepfalusy, Peter
2008-02-15
We study variational wave functions of the product form, factorizing according to the wave vectors k, for the ground state of a system of bosons interacting via positive pair interactions with a positive Fourier transform. Our trial functions are members of different orthonormal bases in Fock space. Each basis contains a quasiparticle vacuum state and states with an arbitrary finite number of quasiparticles. One of the bases is that of Valatin and Butler (VB), introduced fifty years ago and parametrized by an infinite set of variables determining Bogoliubov's canonical transformation for each k. In another case, inspired by Nozieres and Saint James the canonical transformation for k=0 is replaced by a shift in the creation/annihilation operators. For the VB basis we prove that the lowest energy is obtained in a state with {approx}{radical}(volume) quasiparticles in the zero mode. The number of k=0 physical particles is of the order of the volume and its fluctuation is anomalously large, resulting in an excess energy. The same fluctuation is normal in the second type of optimized bases, the minimum energy is smaller and is attained in a vacuum state. Associated quasiparticle theories and questions about the gap in their spectrum are also discussed.
String wave function across a Kasner singularity
Copeland, Edmund J.; Niz, Gustavo; Turok, Neil
2010-06-15
A collision of orbifold planes in 11 dimensions has been proposed as an explanation of the hot big bang. When the two planes are close to each other, the winding membranes become the lightest modes of the theory, and can be effectively described in terms of fundamental strings in a ten-dimensional background. Near the brane collision, the 11-dimensional metric is a Euclidean space times a 1+1-dimensional Milne universe. However, one may expect small perturbations to lead into a more general Kasner background. In this paper we extend the previous classical analysis of winding membranes to Kasner backgrounds, and using the Hamiltonian equations, solve for the wave function of loops with circular symmetry. The evolution across the singularity is regular, and explained in terms of the excitement of higher oscillation modes. We also show there is finite particle production and unitarity is preserved.
Computer network defense through radial wave functions
NASA Astrophysics Data System (ADS)
Malloy, Ian J.
The purpose of this research is to synthesize basic and fundamental findings in quantum computing, as applied to the attack and defense of conventional computer networks. The concept focuses on uses of radio waves as a shield for, and attack against traditional computers. A logic bomb is analogous to a landmine in a computer network, and if one was to implement it as non-trivial mitigation, it will aid computer network defense. As has been seen in kinetic warfare, the use of landmines has been devastating to geopolitical regions in that they are severely difficult for a civilian to avoid triggering given the unknown position of a landmine. Thus, the importance of understanding a logic bomb is relevant and has corollaries to quantum mechanics as well. The research synthesizes quantum logic phase shifts in certain respects using the Dynamic Data Exchange protocol in software written for this work, as well as a C-NOT gate applied to a virtual quantum circuit environment by implementing a Quantum Fourier Transform. The research focus applies the principles of coherence and entanglement from quantum physics, the concept of expert systems in artificial intelligence, principles of prime number based cryptography with trapdoor functions, and modeling radio wave propagation against an event from unknown parameters. This comes as a program relying on the artificial intelligence concept of an expert system in conjunction with trigger events for a trapdoor function relying on infinite recursion, as well as system mechanics for elliptic curve cryptography along orbital angular momenta. Here trapdoor both denotes the form of cipher, as well as the implied relationship to logic bombs.
Nonlinear Trivelpiece-Gould Waves: Frequency, Functional Form, and Stability
NASA Astrophysics Data System (ADS)
Dubin, Daniel H. E.
2015-11-01
This poster considers the frequency, spatial form, and stability, of nonlinear Trivelpiece- Gould (TG) waves on a cylindrical plasma column of length L and radius rp, treating both traveling and standing waves, and focussing on the regime of experimental interest in which L/rp >> 1. In this regime TG waves are weakly dispersive, allowing strong mode-coupling between Fourier harmonics. The mode coupling implies that linear theory for such waves is a poor approximation even at fairly small amplitudes, and nonlinear theories that include only a small number of harmonics (such as 3-wave parametric resonance theory) fail to fully capture the stability properties of the system. We find that nonlinear standing waves suffer jumps in their functional form as their amplitude is varied continuously. The jumps are caused by nonlinear resonances between the standing wave and nearly linear waves whose frequencies and wave numbers are harmonics of the standing wave. Also, the standing waves are found to be unstable to a multi-wave version of 3-wave parametric resonance, with an amplitude required for instability onset that is much larger than expected from three wave theory. For traveling wave, linearly stability is found for all amplitudes that could be studied, in contradiction to 3-wave theory. Supported by National Science Foundation Grant PHY-1414570, Department of Energy Grants DE-SC0002451and DE-SC0008693.
Holographic Wave Functions, Meromorphization and Counting Rules
Anatoly Radyushkin
2006-05-10
We study the large-Q{sup 2} behavior of the meson form factor F{sub M} (Q{sup 2}) constructed using the holographic light-front wave functions proposed recently by Brodsky and de Teramond. We show that this model can be also obtained within the Migdal's regularization approach (''meromorphization''), if one applies it to 3-point function for scalar currents made of scalar quarks. We found that the asymptotic 1/Q{sup 2} behavior of F{sub M} (Q{sup 2}) is generated by soft Feynman mechanism rather than by short distance dynamics, which causes very late onset of the 1/Q{sup 2} asymptotic behavior. It becomes visible only for unaccessible momenta Q{sup 2} {approx}> 10, GeV{sup 2}. Using meromorphization for spin-1/2 quarks, we demonstrated that resulting form factor F{sup spinor}{sub M} (Q{sup 2}) has 1/Q{sup 4} asymptotic behavior. Now, owing to the late onset of this asymptotic pattern, F{sup spinor}{sub M} (Q{sup 2}) imitates the 1/Q{sup 2} behavior in the few GeV{sup 2} region.
Quasirelativistic quasilocal finite wave-function collapse model
Pearle, Philip
2005-03-01
A Markovian wave-function collapse model is presented where the collapse-inducing operator, constructed from quantum fields, is a manifestly covariant generalization of the mass-density operator utilized in the nonrelativistic continuous spontaneous localization (CSL) wave-function collapse model. However, the model is not Lorentz invariant because two such operators do not commute at spacelike separation, i.e., the time-ordering operation in one Lorentz frame, the 'preferred' frame, is not the time-ordering operation in another frame. However, the characteristic spacelike distance over which the commutator decays is the particle's Compton wavelength so, since the commutator rapidly gets quite small, the model is 'almost' relativistic. This quasirelativistic CSL (QRCSL) model is completely finite: unlike previous, relativistic, models, it has no (infinite) energy production from the vacuum state. QRCSL calculations are given of the collapse rate for a single free particle in a superposition of spatially separated packets, and of the energy production rate for any number of free particles: these reduce to the CSL rates if the particle's Compton wavelength is small compared to the model's distance parameter. One motivation for QRCSL is the realization that previous relativistic models entail excitation of nuclear states which exceeds that of experiment, whereas QRCSL does not; an example is given involving quadrupole excitation of the {sup 74}Ge nucleus.
Plant nuclear proteomics for unraveling physiological function.
Yin, Xiaojian; Komatsu, Setsuko
2016-09-25
The nucleus is the subcellular organelle that functions as the regulatory hub of the cell and is responsible for regulating several critical cellular functions, including cell proliferation, gene expression, and cell survival. Nuclear proteomics is a useful approach for investigating the mechanisms underlying plant responses to abiotic stresses, including protein-protein interactions, enzyme activities, and post-translational modifications. Among abiotic stresses, flooding is a major limiting factor for plant growth and yields, particularly for soybean. In this review, plant nuclei purification methods, modifications of plant nuclear proteins, and recent contributions to the field of plant nuclear proteomics are summarized. In addition, to reveal the upstream regulating mechanisms controlling soybean responses to flooding stress, the functions of flooding-responsive nuclear proteins are reviewed based on the results of nuclear proteomic analysis of soybean in the early stages of flooding stress. PMID:27004615
Bohmian mechanics without wave function ontology
NASA Astrophysics Data System (ADS)
Solé, Albert
2013-11-01
In this paper, I critically assess different interpretations of Bohmian mechanics that are not committed to an ontology based on the wave function being an actual physical object that inhabits configuration space. More specifically, my aim is to explore the connection between the denial of configuration space realism and another interpretive debate that is specific to Bohmian mechanics: the quantum potential versus guidance approaches. Whereas defenders of the quantum potential approach to the theory claim that Bohmian mechanics is better formulated as quasi-Newtonian, via the postulation of forces proportional to acceleration; advocates of the guidance approach defend the notion that the theory is essentially first-order and incorporates some concepts akin to those of Aristotelian physics. Here I analyze whether the desideratum of an interpretation of Bohmian mechanics that is both explanatorily adequate and not committed to configuration space realism favors one of these two approaches to the theory over the other. Contrary to some recent claims in the literature, I argue that the quasi-Newtonian approach based on the idea of a quantum potential does not come out the winner.
Imaging the wave functions of adsorbed molecules
Lüftner, Daniel; Ules, Thomas; Reinisch, Eva Maria; Koller, Georg; Soubatch, Serguei; Tautz, F. Stefan; Ramsey, Michael G.; Puschnig, Peter
2014-01-01
The basis for a quantum-mechanical description of matter is electron wave functions. For atoms and molecules, their spatial distributions and phases are known as orbitals. Although orbitals are very powerful concepts, experimentally only the electron densities and -energy levels are directly observable. Regardless whether orbitals are observed in real space with scanning probe experiments, or in reciprocal space by photoemission, the phase information of the orbital is lost. Here, we show that the experimental momentum maps of angle-resolved photoemission from molecular orbitals can be transformed to real-space orbitals via an iterative procedure which also retrieves the lost phase information. This is demonstrated with images obtained of a number of orbitals of the molecules pentacene (C22H14) and perylene-3,4,9,10-tetracarboxylic dianhydride (C24H8O6), adsorbed on silver, which are in excellent agreement with ab initio calculations. The procedure requires no a priori knowledge of the orbitals and is shown to be simple and robust. PMID:24344291
Universal Nuclear Energy Density Functional
Carlson, Joseph; Furnstahl, Richard; Horoi, Mihai; Lusk, Rusty; Nazarewicz, Witold; Ng, Esmond; Thompson, Ian; Vary, James
2012-12-01
An understanding of the properties of atomic nuclei is crucial for a complete nuclear theory, for element formation, for properties of stars, and for present and future energy and defense applications. During the period of Dec. 1 2006 – Jun. 30, 2012, the UNEDF collaboration carried out a comprehensive study of all nuclei, based on the most accurate knowledge of the strong nuclear interaction, the most reliable theoretical approaches, the most advanced algorithms, and extensive computational resources, with a view towards scaling to the petaflop platforms and beyond. Until recently such an undertaking was hard to imagine, and even at the present time such an ambitious endeavor would be far beyond what a single researcher or a traditional research group could carry out.
Meson's correlation functions in a nuclear medium
NASA Astrophysics Data System (ADS)
Park, Chanyong
2016-09-01
We investigate meson's spectrum, decay constant and form factor in a nuclear medium through holographic two- and three-point correlation functions. To describe a nuclear medium composed of protons and neutrons, we consider a hard wall model on the thermal charged AdS geometry and show that due to the isospin interaction with a nuclear medium, there exist splittings of the meson's spectrum, decay constant and form factor relying on the isospin charge. In addition, we show that the ρ-meson's form factor describing an interaction with pseudoscalar fluctuation decreases when the nuclear density increases, while the interaction with a longitudinal part of an axial vector meson increases.
Light Front Wave Function for Hadrons with Arbitrary Twist
NASA Astrophysics Data System (ADS)
Vega, Alfredo; Schmidt, Ivan; Gutsche, Thomas; Lyubovitskij, Valery E.
2016-07-01
We present a phenomenological light-front wave function for hadrons with arbitrary twist dimension (mesons, baryons and multiquark states), which gives the correct scaling behavior of structure functions and form factors. Some examples of his uses are presented.
Light Front Wave Function for Hadrons with Arbitrary Twist
NASA Astrophysics Data System (ADS)
Vega, Alfredo; Schmidt, Ivan; Gutsche, Thomas; Lyubovitskij, Valery E.
2016-05-01
We present a phenomenological light-front wave function for hadrons with arbitrary twist dimension (mesons, baryons and multiquark states), which gives the correct scaling behavior of structure functions and form factors. Some examples of his uses are presented.
Wind-wave source functions in opposing seas
NASA Astrophysics Data System (ADS)
Langodan, Sabique; Cavaleri, Luigi; Viswanadhapalli, Yesubabu; Hoteit, Ibrahim
2015-10-01
The Red Sea is a challenge for wave modeling because of its unique two opposed wave systems, forced by opposite winds and converging at its center. We investigate the different physical aspects of wave evolution and propagation in the convergence zone. The two opposing wave systems have similar amplitude and frequency, each driven by the action of its own wind. Wave patterns at the center of the Red Sea, as derived from extensive tests and intercomparison between model and measured data, suggest that the currently available wave model source functions may not properly represent the evolution of the local fields that appear to be characterized by a less effective wind input and an enhanced white-capping. We propose and test a possible simple solution to improve the wave-model simulation under opposing winds and waves condition.
Wave function continuity and the diagonal Born-Oppenheimer correction at conical intersections.
Meek, Garrett A; Levine, Benjamin G
2016-05-14
We demonstrate that though exact in principle, the expansion of the total molecular wave function as a sum over adiabatic Born-Oppenheimer (BO) vibronic states makes inclusion of the second-derivative nonadiabatic energy term near conical intersections practically problematic. In order to construct a well-behaved molecular wave function that has density at a conical intersection, the individual BO vibronic states in the summation must be discontinuous. When the second-derivative nonadiabatic terms are added to the Hamiltonian, singularities in the diagonal BO corrections (DBOCs) of the individual BO states arise from these discontinuities. In contrast to the well-known singularities in the first-derivative couplings at conical intersections, these singularities are non-integrable, resulting in undefined DBOC matrix elements. Though these singularities suggest that the exact molecular wave function may not have density at the conical intersection point, there is no physical basis for this constraint. Instead, the singularities are artifacts of the chosen basis of discontinuous functions. We also demonstrate that continuity of the total molecular wave function does not require continuity of the individual adiabatic nuclear wave functions. We classify nonadiabatic molecular dynamics methods according to the constraints placed on wave function continuity and analyze their formal properties. Based on our analysis, it is recommended that the DBOC be neglected when employing mixed quantum-classical methods and certain approximate quantum dynamical methods in the adiabatic representation. PMID:27179473
Wave function continuity and the diagonal Born-Oppenheimer correction at conical intersections
NASA Astrophysics Data System (ADS)
Meek, Garrett A.; Levine, Benjamin G.
2016-05-01
We demonstrate that though exact in principle, the expansion of the total molecular wave function as a sum over adiabatic Born-Oppenheimer (BO) vibronic states makes inclusion of the second-derivative nonadiabatic energy term near conical intersections practically problematic. In order to construct a well-behaved molecular wave function that has density at a conical intersection, the individual BO vibronic states in the summation must be discontinuous. When the second-derivative nonadiabatic terms are added to the Hamiltonian, singularities in the diagonal BO corrections (DBOCs) of the individual BO states arise from these discontinuities. In contrast to the well-known singularities in the first-derivative couplings at conical intersections, these singularities are non-integrable, resulting in undefined DBOC matrix elements. Though these singularities suggest that the exact molecular wave function may not have density at the conical intersection point, there is no physical basis for this constraint. Instead, the singularities are artifacts of the chosen basis of discontinuous functions. We also demonstrate that continuity of the total molecular wave function does not require continuity of the individual adiabatic nuclear wave functions. We classify nonadiabatic molecular dynamics methods according to the constraints placed on wave function continuity and analyze their formal properties. Based on our analysis, it is recommended that the DBOC be neglected when employing mixed quantum-classical methods and certain approximate quantum dynamical methods in the adiabatic representation.
High-Frequency Gravitational Wave Induced Nuclear Fusion
Fontana, Giorgio; Baker, Robert M. L. Jr.
2007-01-30
Nuclear fusion is a process in which nuclei, having a total initial mass, combine to produce a single nucleus, having a final mass less than the total initial mass. Below a given atomic number the process is exothermic; that is, since the final mass is less than the combined initial mass and the mass deficit is converted into energy by the nuclear fusion. On Earth nuclear fusion does not happen spontaneously because electrostatic barriers prevent the phenomenon. To induce controlled, industrial scale, nuclear fusion, only a few methods have been discovered that look promising, but net positive energy production is not yet possible because of low overall efficiency of the systems. In this paper we propose that an intense burst of High Frequency Gravitational Waves (HFGWs) could be focused or beamed to a target mass composed of appropriate fuel or target material to efficiently rearrange the atomic or nuclear structure of the target material with consequent nuclear fusion. Provided that efficient generation of HFGW can be technically achieved, the proposed fusion reactor could become a viable solution for the energy needs of mankind and alternatively a process for beaming energy to produce a source of fusion energy remotely - even inside solid materials.
LINCing complex functions at the nuclear envelope
Rothballer, Andrea; Schwartz, Thomas U.; Kutay, Ulrike
2013-01-01
Linker of nucleoskeleton and cytoskeleton (LINC) complexes span the double membrane of the nuclear envelope (NE) and physically connect nuclear structures to cytoskeletal elements. LINC complexes are envisioned as force transducers in the NE, which facilitate processes like nuclear anchorage and migration, or chromosome movements. The complexes are built from members of two evolutionary conserved families of transmembrane (TM) proteins, the SUN (Sad1/UNC-84) domain proteins in the inner nuclear membrane (INM) and the KASH (Klarsicht/ANC-1/SYNE homology) domain proteins in the outer nuclear membrane (ONM). In the lumen of the NE, the SUN and KASH domains engage in an intimate assembly to jointly form a NE bridge. Detailed insights into the molecular architecture and atomic structure of LINC complexes have recently revealed the molecular basis of nucleo-cytoskeletal coupling. They bear important implications for LINC complex function and suggest new potential and as yet unexplored roles, which the complexes may play in the cell. PMID:23324460
Modular matrices from universal wave-function overlaps in Gutzwiller-projected parton wave functions
NASA Astrophysics Data System (ADS)
Mei, Jia-Wei; Wen, Xiao-Gang
2015-03-01
We implement the universal wave-function overlap (UWFO) method to extract modular S and T matrices for topological orders in Gutzwiller-projected parton wave functions (GPWFs). The modular S and T matrices generate a projective representation of S L (2 ,Z ) on the degenerate-ground-state Hilbert space on a torus and may fully characterize the 2+1D topological orders, i.e., the quasiparticle statistics and chiral central charge (up to E8 bosonic quantum Hall states). We use the variational Monte Carlo method to computed the S and T matrices of the chiral spin liquid (CSL) constructed by the GPWF on the square lattice, and we confirm that the CSL carries the same topological order as the ν =1/2 bosonic Laughlin state. We find that the nonuniversal exponents in the UWFO can be small, and direct numerical computation can be applied on relatively large systems. The UWFO may be a powerful method to calculate the topological order in GPWFs.
Joint inversion of body wave receiver function and Rayleigh wave ellipticity
NASA Astrophysics Data System (ADS)
Chong, J.; Ni, S.; Chu, R.
2015-12-01
In recent years, surface wave dispersion has been used to image lithospheric structure jointly with receiver function, or Rayleigh wave ellipticity (Julia et al., 2000; Lin et al., 2012). Because surface wave dispersion is the total propagation effect of the travel path, the joint inversion relies on dense seismic arrays or high seismicity to obtain local velocity structure. However, both receiver function and Rayleigh wave ellipticity are single station measurements with localized sensitivities and could be combined for joint inversion naturally. In this study we explored the feasibility of the joint inversion of Rayleigh wave ellipticity and receiver function. We performed sensitivity tests with forward modeling, and found that the receiver function is sensitive to sharp velocity interfaces but shows weak sensitivity to long wavelength structure, almost complementary to Rayleigh wave ellipticity. Therefore, joint inversion with two single-station measurements provides tighter constraints on the velocity structure beneath the seismic station. A joint inversion algorithm based on the Fast Simulated Annealing method is developed to invert Rayleigh wave ellipticity and receiver function for the lithospheric structure. Application of the algorithm to the Indian Craton and the Williston Basin in the United States demonstrates its effectiveness in reducing the non-uniqueness of the inversion. However, the joint inversion is not sensitive to average crustal velocity, suggesting the need to combine surface wave dispersion, receiver function and Rayleigh wave ellipticity to more accurately resolve the velocity structure. ReferenceJuliá, J., C. Ammon, R. Herrmann, and A. Correig, 2000. Joint inversion of receiver function and surface wave dispersion observations, Geophys. J. Int., 143(1), 99-112. Lin F.C., Schmandt B. and Tsai V.C., 2012. Joint inversion of Rayleigh wave phase velocity and ellipticity using USArray: constraining velocity and density structure in the upper
Double plane wave reverse time migration with plane wave Green's function
NASA Astrophysics Data System (ADS)
Zhao, Z.; Sen, M. K.; Stoffa, P. L.
2015-12-01
Reverse time migration (RTM) is effective in obtaining complex subsurface structures from seismic data. By solving the two-way wave equation, RTM can use entire wavefield for imaging. Although powerful computer are becoming available, the conventional pre-stack shot gather RTM is still computationally expensive. Solving forward and backward wavefield propagation for each source location and shot gather is extremely time consuming, especially for large seismic datasets. We present an efficient, accurate and flexible plane wave RTM in the frequency domain where we utilize a compressed plane wave dataset, known as the double plane wave (DPW) dataset. Provided with densely sampled seismic dataset, shot gathers can be decomposed into source and receiver plane wave components with minimal artifacts. The DPW RTM is derived under the Born approximation and utilizes frequency domain plane wave Green's function for imaging. Time dips in the shot profiles can help to estimate the range of plane wave components present in shot gathers. Therefore, a limited number of plane wave Green's functions are needed for imaging. Plane wave Green's functions can be used for imaging both source and receiver plane waves. Source and receiver reciprocity can be used for imaging plane wave components at no cost and save half of the computation time. As a result, the computational burden for migration is substantially reduced. Plane wave components can be migrated independently to recover specific targets with given dips, and ray parameter common image gathers (CIGs) can be generated after migration directly. The ray parameter CIGs can be used to justify the correctness of velocity models. Subsurface anisotropy effects can also be included in our imaging condition, provided with plane wave Green's functions in the anisotropic media.
Recent progress on nuclear parton distribution functions
NASA Astrophysics Data System (ADS)
Hirai, M.; Kumano, S.; Saito, K.
2011-09-01
We report current status of global analyses on nuclear parton distribution functions (NPDFs). The optimum NPDFs are determined by analyzing high-energy nuclear reaction data. Due to limited experimental measurements, antiquark modifications have large uncertainties at x > 0.2 and gluon modifications cannot be determined. A nuclear modification difference between u and d quark distributions could be an origin of the long-standing NuTeV sin2θw anomaly. There is also an issue of nuclear modification differences between the structure functions of charged-lepton and neutrino reactions. Next, nuclear clustering effects are discussed in structure functions F2A as a possible explanation for an anomalous result in the 9Be nucleus at the Thomas Jefferson National Accelerator Facility (JLab). Last, tensor-polarized quark and antiquark distribution functions are extracted from HERMES data on the polarized structure function b1 of the deuteron, and they could be used for testing theoretical models and for proposing future experiments, for example, the one at JLab. Such measurements could open a new field of spin physics in spin-one hadrons.
Nuclear diffractive structure functions at high energies
Marquet,C.; Kowalski, H.; Lappi, T.; Venugopalan, R.
2008-08-08
A future high-energy electron-ion collider would explore the non-linear weakly-coupled regime of QCD, and test the Color Glass Condensate (CGC) approach to high-energy scattering. Hard diffraction in deep inelastic scattering off nuclei will provide many fundamental measurements. In this work, the nuclear diffractive structure function F{sub 2,A}{sup D} is predicted in the CGC framework, and the features of nuclear enhancement and suppression are discussed.
Boundary conditions on internal three-body wave functions
Mitchell, Kevin A.; Littlejohn, Robert G.
1999-10-01
For a three-body system, a quantum wave function {Psi}{sub m}{sup {ell}} with definite {ell} and m quantum numbers may be expressed in terms of an internal wave function {chi}{sub k}{sup {ell}} which is a function of three internal coordinates. This article provides necessary and sufficient constraints on {chi}{sub k}{sup {ell}} to ensure that the external wave function {Psi}{sub k}{sup {ell}} is analytic. These constraints effectively amount to boundary conditions on {chi}{sub k}{sup {ell}} and its derivatives at the boundary of the internal space. Such conditions find similarities in the (planar) two-body problem where the wave function (to lowest order) has the form r{sup |m|} at the origin. We expect the boundary conditions to prove useful for constructing singularity free three-body basis sets for the case of nonvanishing angular momentum.
Nonstandard jump functions for radially symmetric shock waves
Baty, Roy S.; Tucker, Don H.; Stanescu, Dan
2008-10-01
Nonstandard analysis is applied to derive generalized jump functions for radially symmetric, one-dimensional, magnetogasdynamic shock waves. It is assumed that the shock wave jumps occur on infinitesimal intervals, and the jump functions for the physical parameters occur smoothly across these intervals. Locally integrable predistributions of the Heaviside function are used to model the flow variables across a shock wave. The equations of motion expressed in nonconservative form are then applied to derive unambiguous relationships between the jump functions for the physical parameters for two families of self-similar flows. It is shown that the microstructures for these families of radially symmetric, magnetogasdynamic shock waves coincide in a nonstandard sense for a specified density jump function
Nonstandard jump functions for radically symmetric shock waves
Baty, Roy S; Tucker, Don H; Stanescu, Dan
2008-01-01
Nonstandard analysis is applied to derive generalized jump functions for radially symmetric, one-dimensional, magnetogasdynamic shock waves. It is assumed that the shock wave jumps occur on infinitesimal intervals and the jump functions for the physical parameters occur smoothly across these intervals. Locally integrable predistributions of the Heaviside function are used to model the flow variables across a shock wave. The equations of motion expressed in nonconservative form are then applied to derive unambiguous relationships between the jump functions for the physical parameters for two families of self-similar flows. It is shown that the microstructures for these families of radially symmetric, magnetogasdynamic shock waves coincide in a nonstandard sense for a specified density jump function.
Nuclear modifications of Parton Distribution Functions
NASA Astrophysics Data System (ADS)
Adeluyi, Adeola Adeleke
This dissertation addresses a central question of modern nuclear physics: how does the behavior of fundamental degrees of freedom (quarks and gluons) change in the nuclear environment? This is an important aspect of experimental studies at current facilities such as the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory and the Continuous Electron Beam Accelerator Facility (CEBAF) at the Thomas Jefferson National Laboratory (JLAB). It is also highly relevant to planned experimental efforts at the Large Hadron Collider (LHC) and the future Electron Ion Collider (EIC). All these facilities probe matter via collisions involving nuclei; thus complications arise due to the presence of the attendant nuclear medium. Theoretical efforts to understand and interpret experimental results from such collisions are therefore largely dependent on the resolution of this question. The development of nuclear physics demonstrates that theoretical description is most efficient in terms of the effective degrees of freedom relevant to the scale (energy) being probed. Thus at low energies, nuclei are described as bound states of protons and neutrons (nucleons). At higher energies, the nucleons are no longer elementary, but are revealed to possess an underlying substructure: they are made up of quarks and gluons, collectively termed partons. The mometum distributions of these partons in the nucleon are referred to as Parton Distribution Functions (PDFs). Parton distributions can be determined from experimental measurements of structure functions. The ratio of nuclear structure functions to nucleon structure functions (generically referred to as nuclear ratio) is a measure of the nuclear modifications of the free nucleon PDFs. Thus a study of the nuclear ratio suffices to gain an understanding of nuclear modifications. In this dissertation we aim to describe theoretically nuclear modifications in a restricted region where the nuclear ratio is less than unity, the so
Nuclear power-plant safety functions
Corcoran, W.R.; Finnicum, D.J.; Hubbard, F.R. III; Musick, C.R.; Walzer, P.F.
1981-03-01
The concept of safety functions is discussed. Ten critical safety functions and the multiple success paths available for accomplishing them are described. Use of the safety function concept in the development of emergency procedures, operator training, and control-room displays provides a systematic approach and a hierarchy of protection that an operator can use to mitigate the consequences of an event. The safety function concept can also be applied to the design and analysis of nuclear plant systems and to the evaluation of past expierience.
Calculation of electron wave functions and refractive index of Ne
NASA Astrophysics Data System (ADS)
Zhu, Min; Liu, Wei; Zhang, Tao
2008-10-01
The radial wave functions of inner electron shell and outer electron shell of a Ne atom were obtained by the approximate analytical method and tested by calculating the ground state energy of the Ne atom. The equivalent volume of electron cloud and the refractive index of Ne were calculated. The calculated refractive index agrees well with the experimental result. Relationship between the refractive index and the wave function of Ne was discovered.
Structure of the number-projected BCS wave function
NASA Astrophysics Data System (ADS)
Dukelsky, J.; Pittel, S.; Esebbag, C.
2016-03-01
We study the structure of the number-projected BCS (PBCS) wave function in the particle-hole basis, displaying its similarities with coupled clusters theory (CCT). The analysis of PBCS together with several modifications suggested by the CCT wave function is carried out for the exactly solvable Richardson model involving a pure pairing Hamiltonian acting in a space of equally spaced, doubly degenerate levels. We point out the limitations of PBCS to describe the nonsuperconducting regime and suggest possible avenues for improvement.
Multi-time wave functions for quantum field theory
Petrat, Sören; Tumulka, Roderich
2014-06-15
Multi-time wave functions such as ϕ(t{sub 1},x{sub 1},…,t{sub N},x{sub N}) have one time variable t{sub j} for each particle. This type of wave function arises as a relativistic generalization of the wave function ψ(t,x{sub 1},…,x{sub N}) of non-relativistic quantum mechanics. We show here how a quantum field theory can be formulated in terms of multi-time wave functions. We mainly consider a particular quantum field theory that features particle creation and annihilation. Starting from the particle–position representation of state vectors in Fock space, we introduce multi-time wave functions with a variable number of time variables, set up multi-time evolution equations, and show that they are consistent. Moreover, we discuss the relation of the multi-time wave function to two other representations, the Tomonaga–Schwinger representation and the Heisenberg picture in terms of operator-valued fields on space–time. In a certain sense and under natural assumptions, we find that all three representations are equivalent; yet, we point out that the multi-time formulation has several technical and conceptual advantages. -- Highlights: •Multi-time wave functions are manifestly Lorentz-covariant objects. •We develop consistent multi-time equations with interaction for quantum field theory. •We discuss in detail a particular model with particle creation and annihilation. •We show how multi-time wave functions are related to the Tomonaga–Schwinger approach. •We show that they have a simple representation in terms of operator valued fields.
The Pion Renormalized Light-Cone Wave Function
NASA Astrophysics Data System (ADS)
Trawiński, Arkadiusz P.
2016-06-01
An approximate light-cone wave function for the pion effective quark-antiquark Fock sector corresponding to a small value of the renormalization group parameter is presented. The approximate wave function is motivated by the LF-holography and the quadratic confinement potential in the front form of Hamiltonian dynamics, which is in harmony with the linear confining potential in the instant form. The pion radius, decay constant and form-factor are also presented.
MILLIMETER-WAVE MONITORING OF NUCLEAR WASTE GLASS MELTS - AN OVERVIEW
Molten glass characteristics of temperature, resistivity, and viscosity can be monitored reliably in the high temperature and chemically corrosive environment of nuclear waste glass melters using millimeter-wave sensor technology. Millimeter-waves are ideally suited for such meas...
Progress on nuclear modifications of structure functions
NASA Astrophysics Data System (ADS)
Kumano, S.
2016-03-01
We report progress on nuclear structure functions, especially on their nuclear modifications and a new tensor structure function for the deuteron. To understand nuclear structure functions is an important step toward describing nuclei and QCD matters from low to high densities and from low to high energies in terms of fundamental quark and gluon degrees of freedom beyond conventional hadron and nuclear physics. It is also practically important for understanding new phenomena in high-energy heavy-ion collisions at RHIC and LHC. Furthermore, since systematic errors of current neutrinooscillation experiments are dominated by uncertainties of neutrino-nucleus interactions, such studies are valuable for finding new physics beyond current framework. Next, a new tensor-polarized structure function b1 is discussed for the deuteron. There was a measurement by HERMES; however, its data are inconsistent with the conventional convolution estimate based on the standard deuteron model with D-state admixture. This fact suggests that a new hadronic phenomenon should exist in the tensor-polarized deuteron at high energies, and it will be experimentally investigated at JLab from the end of 2010's.
Nuclear moments in covariant density functional theory
NASA Astrophysics Data System (ADS)
Meng, J.; Zhao, P. W.; Zhang, S. Q.; Hu, J. N.; Li, J.
2014-05-01
Recent progresses on microscopic and self-consistent description of the nuclear moments in covariant density functional theory based on a point-coupling interaction are briefly reviewed. In particular, the electric quadrupole moments of Cd isotopes and the magnetic moments of Pb isotopes are discussed.
Improved variational wave functions for few-body nuclei
Wiringa, R.B.; Arriaga, A.; Pandharipande, V.R.
1995-08-01
We continued to work on improvements to our variational wave functions for use in Monte Carlo calculations of few-body nuclei. These trial functions include central, spin, isospin, tensor, and spin-orbit two-body correlations and three-body correlations for the three-nucleon potential. In the last two years we studied a variety of extra three-body correlations. Our search for possible forms was guided by comparisons made with 34-channel Faddeev wave functions provided by the Los Alamos-Iowa group. The new trial functions reduce the discrepancy with exact Faddeev calculations in {sup 3}H and Green`s Function Monte Carlo (GFMC) calculations in {sup 4}He by about 40%. This work is now being written up for publication. We hope to use similar comparisons with GFMC calculations in the six-body nuclei to find further improvements for the light p-shell nuclei, where the variational wave functions are not as good.
The effect of meson wave function on heavy-quark fragmentation function
NASA Astrophysics Data System (ADS)
Moosavi Nejad, S. Mohammad
2016-05-01
We calculate the process-independent fragmentation functions (FFs) for a heavy quark to fragment into heavy mesons considering the effects of meson wave function. In all previous works, where the FFs of heavy mesons or heavy baryons were calculated, a delta function form was approximated for the wave function of hadrons. Here, for the first time, we consider a typical mesonic wave function which is different from the delta function and is the nonrelativistic limit of the solution of Bethe-Salpeter equation with the QCD kernel. We shall present our numerical results for the heavy FFs and show how the proposed wave function improves the previous results. As an example, we focus on the fragmentation function for c -quark to split into S -wave D^0 -meson and compare our results with experimental data from BELLE and CLEO.
Mechanical regulation of nuclear structure and function.
Martins, Rui P; Finan, John D; Guilak, Farshid; Lee, David A
2012-01-01
Mechanical loading induces both nuclear distortion and alterations in gene expression in a variety of cell types. Mechanotransduction is the process by which extracellular mechanical forces can activate a number of well-studied cytoplasmic signaling cascades. Inevitably, such signals are transduced to the nucleus and induce transcription factor-mediated changes in gene expression. However, gene expression also can be regulated through alterations in nuclear architecture, providing direct control of genome function. One putative transduction mechanism for this phenomenon involves alterations in nuclear architecture that result from the mechanical perturbation of the cell. This perturbation is associated with direct mechanical strain or osmotic stress, which is transferred to the nucleus. This review describes the current state of knowledge relating the nuclear architecture and the transfer of mechanical forces to the nucleus mediated by the cytoskeleton, the nucleoskeleton, and the LINC (linker of the nucleoskeleton and cytoskeleton) complex. Moreover, remodeling of the nucleus induces alterations in nuclear stiffness, which may be associated with cell differentiation. These phenomena are discussed in relation to the potential influence of nuclear architecture-mediated mechanoregulation of transcription and cell fate. PMID:22655599
Nuclear structure functions at small x
Jalilian-Marian, Jamal
2009-11-15
I study the nuclear structure function F{sub 2}{sup A} and its logarithmic derivative in the high-energy limit (small-x region) using the color glass condensate formalism. In this limit the structure function F{sub 2} depends on the quark-antiquark dipole-target scattering cross section N{sub F}(x{sub bj},r{sub t},b{sub t}). The same dipole cross section appears in single-hadron and hadron-photon production cross sections in the forward rapidity region in deuteron (proton)-nucleus collisions at high energy, that is, at energies available at the BNL Relativistic Heavy Ion Collider (RHIC) and the CERN Large Hadron Collider (LHC). I use a parametrization of the dipole cross section, which has successfully been used to describe the deuteron-gold data at the RHIC, to compute the nuclear structure function F{sub 2}{sup A} and its log Q{sup 2} derivative (which is related to gluon distribution function in the double log limit). I provide a quantitative estimate of the nuclear shadowing of F{sub 2}{sup A} and the gluon distribution function in the kinematic region relevant to a future electron-ion collider.
Nonlinear radiation damping of nuclear spin waves and magnetoelastic waves in antiferromagnets
NASA Astrophysics Data System (ADS)
Andrienko, Alexander V.; Safonov, Vladimir L.
2016-03-01
Parallel pumping of nuclear spin waves in antiferromagnetic CsMnF3 at liquid helium temperatures and magnetoelastic waves in antiferromagnetic FeBO3 at liquid nitrogen temperature in a helical resonator was studied. It was found that the absorbed microwave power is approximately equal to the irradiated power from the sample and that the main restriction mechanism of absorption in both cases is defined by the nonlinear radiation damping predicted about two decades ago. Nonlinear radiation damping is sure to be a common feature of the parallel pumping technique for all normal magnetic excitations and it must be taken into account for interpretation of nonlinear phenomena in parametrically excited magnetic systems.
Parametric dependence of ocean wave-radar modulation transfer functions
NASA Technical Reports Server (NTRS)
Plant, W. J.; Keller, W. C.; Cross, A.
1983-01-01
Microwave techniques at X and L band were used to determine the dependence of ocean-wave radar modulation transfer functions (MTFs) on various environmental and radar parameters during the Marine Remote Sensing experiment of 1979 (MARSEN 79). These MIF are presented, as are coherence functions between the AM and FM parts of the backscattered microwave signal. It is shown that they both depend on several of these parameters. Besides confirming many of the properties of transfer functions reported by previous authors, indications are found that MTFs decrease with increasing angle between wave propagation and antenna-look directions but are essentially independent of small changes in air-sea temperature difference. However, coherence functions are much smaller when the antennas are pointed perpendicular to long waves. It is found that X band transfer functions measured with horizontally polarized microwave radiation have larger magnitudes than those obtained by using vertical polarization.
Pfaffian wave functions and topology of fermion nodes
NASA Astrophysics Data System (ADS)
Mitas, Lubos
2007-03-01
Pfaffian is defined as a signed sum of all pair partitions of even number of elements and it can be viewed as a nontrivial generalization of determinant. Pfaffian enables to define the simplest possible antisymmetric wave function based on pair spinorbital(s) and therefore represents a pairing generalization of the Slater determinant of one-particle orbitals. Pfaffians actually accomodate several types of pairing wave functions, for example, one special case is the Bardeen-Cooper- Schrieffer wave function. Using this platform we propose pfaffian wave functions with simultaneous pairings both in singlet and triplet channels and we benchmark their performance in fixed-node quantum Monte Carlo. We implement Gaussian elimination-like algorithm which enables to calculate pfaffians with efficiency similar to calculation of determinants. For a testing set of first row atoms and molecules we show that single pfaffians provide correlation energies systematically at the level of about 95%. Linear combinations of small number of pfaffians recover another fraction of the missing correlation energy comparable to significantly larger determinantal expansions. In addition, we show that pfaffians possess an important property of fermionic wave functions, namely, the minimal number of two nodal domains defined by fermion nodes. This is related to the proof that under rather general conditions closed-shell ground state wave functions of fermionic systems in d>1 have two nodal domains for arbitrary system size. The explicit proofs cover a number of paradigmatic models such as fermions on a sphere surface, in a periodic box, atomic states, etc, and we discuss the implications of this on efficient construction of wave functions and on several types of many-body effects. Supported by NSF and done in collaboration with M. Bajdich, L.K. Wagner, G. Drobny, and K.E Schmidt.Refs: L. Mitas, PRL 96, 240402 (2006); L. Mitas, cond-mat/0605550; M. Bajdich et al, PRL 96, 130201 (2006); cond
Rossby wave Green's functions in an azimuthal wind
NASA Astrophysics Data System (ADS)
Webb, G. M.; Duba, C. T.; Hu, Q.
2016-05-01
Green's functions for Rossby waves in an azimuthal wind are obtained, in which the stream-function $\\psi$ depends on $r$, $\\phi$ and $t$, where $r$ is cylindrical radius and $\\phi$ is the azimuthal angle in the $\\beta$-plane relative to the easterly direction, in which the $x$-axis points east and the $y$-axis points north. The Rossby wave Green's function with no wind is obtained using Fourier transform methods, and is related to the previously known Green's function obtained for this case, which has a different but equivalent form to the Green's function obtained in the present paper. We emphasize the role of the wave eikonal solution, which plays an important role in the form of the solution. The corresponding Green's function for a rotating wind with azimuthal wind velocity ${\\bf u}=\\Omega r{\\bf e}_\\phi$ ($\\Omega=$const.) is also obtained by Fourier methods, in which the advective rotation operator in position space is transformed to a rotation operator in ${\\bf k}$ transform space. The finite Rossby deformation radius is included in the analysis. The physical characteristics of the Green's functions are delineated and applications are discussed. In the limit as $\\Omega\\to 0$, the rotating wind Green's function reduces to the Rossby wave Green function with no wind.
Adjustment of Born-Oppenheimer electronic wave functions to simplify close coupling calculations.
Buenker, Robert J; Liebermann, Heinz-Peter; Zhang, Yu; Wu, Yong; Yan, Lingling; Liu, Chunhua; Qu, Yizhi; Wang, Jianguo
2013-04-30
Technical problems connected with use of the Born-Oppenheimer clamped-nuclei approximation to generate electronic wave functions, potential energy surfaces (PES), and associated properties are discussed. A computational procedure for adjusting the phases of the wave functions, as well as their order when potential crossings occur, is presented which is based on the calculation of overlaps between sets of molecular orbitals and configuration interaction eigenfunctions obtained at neighboring nuclear conformations. This approach has significant advantages for theoretical treatments describing atomic collisions and photo-dissociation processes by means of ab initio PES, electronic transition moments, and nonadiabatic radial and rotational coupling matrix elements. It ensures that the electronic wave functions are continuous over the entire range of nuclear conformations considered, thereby greatly simplifying the process of obtaining the above quantities from the results of single-point Born-Oppenheimer calculations. The overlap results are also used to define a diabatic transformation of the wave functions obtained for conical intersections that greatly simplifies the computation of off-diagonal matrix elements by eliminating the need for complex phase factors. PMID:23345171
Joint Resummation for TMD Wave Function of Pion
NASA Astrophysics Data System (ADS)
Wang, Yu-Ming
2015-02-01
QCD corrections to transverse-momentum-dependent pion wave function develop the mixed double logarithm ln x ln(ζ P2/k_T^2), when the gluon emission is collinear to the energetic pion. The fist scheme-independent kT factorization formula for γ*π → γ transition form factor is achieved by resumming all the enhanced logarithms for both pion wave function and short-distance coefficient function. High-order QCD corrections and transfer momentum √ {Q2} dependence of pion form factor are found to be distinct from those predicted by the conventional resummation approach.
Perturbations in vibrational diatomic spectra: Factorization of the molecular wave function
Lefebvre, R.
2015-02-21
The coupling between two electronic states of a diatomic molecule may lead to an erratic behaviour of the associated vibrational energies. An example is the homogeneous coupling between the valence b′ state and the Rydberg c′ state of the N{sub 2} molecule, both of symmetry {sup 1}Σ{sub u}{sup +}. The standard treatment of such a situation is to write the wave function as a sum of two Born-Oppenheimer products. It has recently been argued [L. S. Cederbaum, J. Chem. Phys. 138, 224110 (2013); N. I. Gidopoulos and E. K. U. Gross, Philos. Trans. R. Soc., A 372, 20130059 (2014)] that even in such a case the wave function should be representable as a single product, with an electronic factor depending parametrically on nuclear positions and a nuclear factor. We setup such a representation in the case of the perturbations in the N{sub 2} molecule.
Building a Universal Nuclear Energy Density Functional
Carlson, Joe A.; Furnstahl, Dick; Horoi, Mihai; Lust, Rusty; Nazaewicc, Witek; Ng, Esmond; Thompson, Ian; Vary, James
2012-12-30
During the period of Dec. 1 2006 – Jun. 30, 2012, the UNEDF collaboration carried out a comprehensive study of all nuclei, based on the most accurate knowledge of the strong nuclear interaction, the most reliable theoretical approaches, the most advanced algorithms, and extensive computational resources, with a view towards scaling to the petaflop platforms and beyond. The long-term vision initiated with UNEDF is to arrive at a comprehensive, quantitative, and unified description of nuclei and their reactions, grounded in the fundamental interactions between the constituent nucleons. We seek to replace current phenomenological models of nuclear structure and reactions with a well-founded microscopic theory that delivers maximum predictive power with well-quantified uncertainties. Specifically, the mission of this project has been three-fold: First, to find an optimal energy density functional (EDF) using all our knowledge of the nucleonic Hamiltonian and basic nuclear properties; Second, to apply the EDF theory and its extensions to validate the functional using all the available relevant nuclear structure and reaction data; Third, to apply the validated theory to properties of interest that cannot be measured, in particular the properties needed for reaction theory.
Expansion of X-ray form factor for close shell using uncorrelated wave function
AL-Robayi, Enas M.
2013-12-16
The atomic scattering factor has been studied for Be+ve, and B+2ve ions using the uncorrelated wave function (Hartree-Fock (HF)) for inter particle electronic shells. The physical importance of this factor appears in its relation to several important atomic properties as, the coherent scattering intensity, the total scattering intensity, the incoherent scattering function, the coherent scattering cross section, the total incoherent cross section, the nuclear magnetic shielding constant, the geometrical structure factor. Also there is one atomic properties the one particle radial density distribution function D(r)has been studied using the partitioning technique.
Evolution of wave function in a dissipative system
NASA Technical Reports Server (NTRS)
Yu, Li-Hua; Sun, Chang-Pu
1994-01-01
For a dissipative system with Ohmic friction, we obtain a simple and exact solution for the wave function of the system plus the bath. It is described by the direct product in two independent Hilbert space. One of them is described by an effective Hamiltonian, the other represents the effect of the bath, i.e., the Brownian motion, thus clarifying the structure of the wave function of the system whose energy is dissipated by its interaction with the bath. No path integral technology is needed in this treatment. The derivation of the Weisskopf-Wigner line width theory follows easily.
Nuclear parton distribution functions and their uncertainties
Hirai, M.; Kumano, S.; Nagai, T.-H.
2004-10-01
We analyze experimental data of nuclear structure-function ratios F{sub 2}{sup A}/F{sub 2}{sup A{sup '}} and Drell-Yan cross section ratios for obtaining optimum parton distribution functions (PDFs) in nuclei. Then, uncertainties of the nuclear PDFs are estimated by the Hessian method. Valence-quark distributions are determined by the F{sub 2} data at large x; however, the small-x part is not obvious from the data. On the other hand, the antiquark distributions are determined well at x{approx}0.01 from the F{sub 2} data and at x{approx}0.1 by the Drell-Yan data; however, the large-x behavior is not clear. Gluon distributions cannot be fixed by the present data and they have large uncertainties in the whole x region. Parametrization results are shown in comparison with the data. We provide a useful code for calculating nuclear PDFs at given x and Q{sup 2}.
Two-dimensional Coulomb scattering of a quantum particle: Wave functions and Green's functions
NASA Astrophysics Data System (ADS)
Pupyshev, V. V.
2016-02-01
We solve the problem of the propagation of a charged quantum particle in a two-dimensional plane embedded in the three-dimensional coordinate space. We consider scattering of this particle by a stable Coulomb center situated in the same plane. We study the wave function of this particle, its Green's function, and all radial components of these functions. We derive uniform majorant bounds on absolute values of these functions and find the wave function representation in terms of regular radial Coulomb functions and the scattering amplitude representation via partial phases. We obtain integral representations of the Greens's function and all its radial components.
Green's function Monte Carlo in nuclear physics
Carlson, J.
1990-01-01
We review the status of Green's Function Monte Carlo (GFMC) methods as applied to problems in nuclear physics. New methods have been developed to handle the spin and isospin degrees of freedom that are a vital part of any realistic nuclear physics problem, whether at the level of quarks or nucleons. We discuss these methods and then summarize results obtained recently for light nuclei, including ground state energies, three-body forces, charge form factors and the coulomb sum. As an illustration of the applicability of GFMC to quark models, we also consider the possible existence of bound exotic multi-quark states within the framework of flux-tube quark models. 44 refs., 8 figs., 1 tab.
Hydrodynamic waves and correlation functions in dusty plasmas
Wang, X.; Bhattacharjee, A.
1997-11-01
A hydrodynamic description of strongly coupled dusty plasmas is given when physical quantities vary slowly in space and time and the system can be assumed to be in local thermodynamic equilibrium. The linear waves in such a system are analyzed. In particular, a dispersion equation is derived for low-frequency dust acoustic waves, including collisional damping effects, and compared with experimental results. The linear response of the system is calculated from the fluctuation-dissipation theorem and the hydrodynamic equations. The requirement that these two calculations coincide constrains the particle correlation function for slowly varying perturbations. It is shown that in the presence of weakly damped, long-wavelength dust-acoustic waves, the dust autocorrelation function is of the Debye{endash}H{umlt u}ckel form and the characteristic shielding distance is the dust Debye length. {copyright} {ital 1997 American Institute of Physics.}
Oblique propagation, wave particle interaction and particle distribution function
NASA Astrophysics Data System (ADS)
Osmane, Adnane; Hamza, A. M.; Meziane, Karim
Recent results from the Cluster mission have stimulated theoretical investigations and simulations to explain ion distribution functions observed in the quasi-perp bow shock. High-time resolution observations have revealed distributions of gyrating ions that are gyrophase-bunched. When not produced at the shock, such distributions are believed to be resulting from interactions between field-aligned beams and low frequency beamdriven waves . The Conventional models used to account for such distributions assume that the waves are purely transverse, and that they propagate parallel to the ambient magnetic eld. However observations indicate that these waves are propagating obliquely with respect to the ambient magnetic eld [Meziane et al., 2001]. A theoretical investigation of the non-relativistic wave-particle interaction in a background magnetic eld with the electromagnetic wave propagating obliquely has been addressed previously, resulting in a dynamical system describing the wave interaction with a single ion in the absence of dissipation mechanisms. [Hamza et al., 2005] This dynamical system has been numerically integrated to construct the ion distribution functions by seeding the particles with di erent initial conditions. We compute the particle orbits and simulate the time evolution of the distribution functions based on Liouville's theorem of phase space density conservation. It will be shown that the trapping which is due to the oblique propagation of the wave, gives an explanation for gyrophase-bunching and unstable distributions in velocity space which could trigger instabilities such as firehose and mirror. Therefore this exercise provide insights on the particle dynamics and onset of waves away from the shock. Meziane, K., C. Mazelle, R.P. Lin, D. LeQueau, D.E. Larson, G.K. Parks, R.P. Lepping (2001), Three dimensional observations of gyrating ions distributions far upstream from the Earth's bow shock and their association with low-frequency waves, J
Source Time Function of P-wave Acceleration
NASA Astrophysics Data System (ADS)
Chen, K. J.
2015-12-01
In this study, the site effect of time function of the Taiwan area will be invested. The recorded response function of a single earthquake will be calculated by Complex Demodulation. The path effect of each event-station pair will be estimated by using the forward method with a 3-D attenuation structure. After removing the path effect, the source frequency function of each single event will be obtained by averaging the whole station gotten. Using this source time function to calculate the path effect of the all stations, the theoretic received time frequency function can be obtained. The difference between this theoretic function and the recorded function is the site effect function of the single station. The characterics of the site effect in Taiwan area will be analyzed. Recalculate the path effect and remove the site effect of each station to get the new source time function of P-wave acceleration.
Correlated Strength in the Nuclear Spectral Function
D. Rohe; C. S. Armstrong; R. Asaturyan; O. K. Baker; S. Bueltmann; C. Carasco; D. Day; R. Ent; H. C. Fenker; K. Garrow; A. Gasparian; P. Gueye; M. Hauger; A. Honegger; J. Jourdan; C. E. Keppel; G. Kubon; R. Lindgren; A. Lung; D. J. Mack; J. H. Mitchell; H. Mkrtchyan; D. Mocelj; K. Normand; T. Petitjean; O. Rondon; E. Segbefia; I. Sick; S. Stepanyan; L. Tang; F. Tiefenbacher; W. F. Vulcan; G. Warren; S. A. Wood; L. Yuan; M. Zeier; H. Zhu; B. Zihlmann
2004-10-01
We have carried out an (e,ep) experiment at high momentum transfer and in parallel kinematics to measure the strength of the nuclear spectral function S(k,E) at high nucleon momenta k and large removal energies E. This strength is related to the presence of short-range and tensor correlations, and was known hitherto only indirectly and with considerable uncertainty from the lack of strength in the independent-particle region. This experiment locates by direct measurement the correlated strength predicted by theory.
Dark energy and normalization of the cosmological wave function
NASA Astrophysics Data System (ADS)
Huang, Peng; Huang, Yue; Li, Miao; Li, Nan
2016-08-01
Dark energy is investigated from the perspective of quantum cosmology. It is found that, together with an appropriate normal ordering factor q, only when there is dark energy can the cosmological wave function be normalized. This interesting observation may require further attention.
Simulation of wind wave growth with reference source functions
NASA Astrophysics Data System (ADS)
Badulin, Sergei I.; Zakharov, Vladimir E.; Pushkarev, Andrei N.
2013-04-01
We present results of extensive simulations of wind wave growth with the so-called reference source function in the right-hand side of the Hasselmann equation written as follows First, we use Webb's algorithm [8] for calculating the exact nonlinear transfer function Snl. Second, we consider a family of wind input functions in accordance with recent consideration [9] ( )s S = ?(k)N , ?(k) = ? ? ?- f (?). in k 0 ?0 in (2) Function fin(?) describes dependence on angle ?. Parameters in (2) are tunable and determine magnitude (parameters ?0, ?0) and wave growth rate s [9]. Exponent s plays a key role in this study being responsible for reference scenarios of wave growth: s = 4-3 gives linear growth of wave momentum, s = 2 - linear growth of wave energy and s = 8-3 - constant rate of wave action growth. Note, the values are close to ones of conventional parameterizations of wave growth rates (e.g. s = 1 for [7] and s = 2 for [5]). Dissipation function Sdiss is chosen as one providing the Phillips spectrum E(?) ~ ?5 at high frequency range [3] (parameter ?diss fixes a dissipation scale of wind waves) Sdiss = Cdissμ4w?N (k)θ(? - ?diss) (3) Here frequency-dependent wave steepness μ2w = E(?,?)?5-g2 makes this function to be heavily nonlinear and provides a remarkable property of stationary solutions at high frequencies: the dissipation coefficient Cdiss should keep certain value to provide the observed power-law tails close to the Phillips spectrum E(?) ~ ?-5. Our recent estimates [3] give Cdiss ? 2.0. The Hasselmann equation (1) with the new functions Sin, Sdiss (2,3) has a family of self-similar solutions of the same form as previously studied models [1,3,9] and proposes a solid basis for further theoretical and numerical study of wave evolution under action of all the physical mechanisms: wind input, wave dissipation and nonlinear transfer. Simulations of duration- and fetch-limited wind wave growth have been carried out within the above model setup to check its
Vector Meson Form Factors and Wave Functions from Holographic QCD
Hovhannes Grigoryan; Anatoly Radyushkin
2007-10-10
Based on the holographic dual model of QCD, we study 2- and 3-point functions of vector currents and derive form factors as well as wave functions for the vector mesons. As a result, generalized vector-meson dominance representation for form factors is obtained with a very specific VMD pattern. The calculated electric radius of the rho-meson is shown to be in a good agreement with predictions from lattice QCD.
Refined applications of the collapse of the wave function
NASA Astrophysics Data System (ADS)
Stodolsky, L.
2015-05-01
In a two-part system, the collapse of the wave function of one part can put the other part in a state which would be difficult or impossible to achieve otherwise, in particular, one sensitive to small effects in the "collapse" interaction. We present some applications to the very symmetric and experimentally accessible situations of the decays ϕ (1020 )→KoKo , ψ (3770 )→DoDo, or ϒ (4 s )→BoBo , involving the internal state of the two-state Ko, Do, or Bo mesons. The collapse of the wave function occasioned by a decay of one member of the pair (away side) fixes the state vector of that side's two-state system. Bose-Einstein statistics then determines the state of the recoiling meson (near side), whose evolution can then be followed further. In particular, the statistics requirement dictates that the "away side" and "near side" internal wave functions must be orthogonal at the time of the collapse. Thus a C P violation in the away side decay implies a complementary C P impurity on the near side, which can be detected in the further evolution. The C P violation so manifested is necessarily direct C P violation, since neither the mass matrix nor time evolution was involved in the collapse. A parametrization of the direct C P violation is given, and various manifestations are presented. Certain rates or combination of rates are identified which are nonzero only if there is direct C P violation. The very explicit and detailed use made of the collapse of the wave function makes the procedure interesting with respect to the fundamentals of quantum mechanics. We note an experimental consistency test for our treatment of the collapse of the wave function, which can be carried out by a certain measurement of partial decay rates.
How close can we get waves to wave functions, including potential?
NASA Astrophysics Data System (ADS)
Faletič, Sergej
2016-05-01
In the following article we show that mechanical waves on a braced string can have the same shapes as important wave functions in introductory quantum mechanics. A braced string is a string with additional transversal springs that serve as external "potential". The aim is not to suggest teaching quantum mechanics with these analogies. Instead, the aim is to provide students with some additional relevant experience in wave mechanics before they are introduced to quantum mechanics. We show how this experience can be used in a constructivist sense as the basis for building quantum concepts. We consider energy transfer along such string and show that penetration of a wave into a region with high "potential" is not unexpected. We also consider energy transfer between two such strings and show that it can appear point-like even though the wave is an extended object. We also suggest that applying quantization of energy transfer to wave phenomena can explain some of the more difficult to accept features of quantum mechanics.
Occupation-number-based energy functional for nuclear masses
Bertolli, Michael G.; Papenbrock, Thomas F; Wild, S. M.
2012-01-01
We develop an energy functional with shell-model occupations as the relevant degrees of freedom and compute nuclear masses across the nuclear chart. The functional is based on Hohenberg-Kohn theory with phenomenologically motivated terms. A global fit of the 17-parameter functional to 2049 nuclear masses yields a root-mean-square deviation of =1.31 MeV. Nuclear radii are computed within a model that employs the resulting occupation numbers.
Occupation number-based energy functional for nuclear masses.
Bertolli, M.; Papenbrock, T.; Wild, S. M.
2012-01-01
We develop an energy functional with shell-model occupations as the relevant degrees of freedom and compute nuclear masses across the nuclear chart. The functional is based on Hohenberg-Kohn theory with phenomenologically motivated terms. A global fit of the 17-parameter functional to 2049 nuclear masses yields a root-mean-square deviation of {chi} = 1.31 MeV. Nuclear radii are computed within a model that employs the resulting occupation numbers.
Local properties of three-body atomic wave functions
Krivec, R.; Mandelzweig, V. B.; Varga, K.
2000-06-01
The local properties and accuracy of the positronium negative-ion (Ps{sup -}) ground-state wave functions obtained by the stochastic variational method (SVM) and by direct solution of the Schroedinger equation with the help of the correlation-function hyperspherical-harmonic method (CFHHM) are studied and compared. Though the energy, calculated by both methods, agrees to up to ten digits, the amplitudes of the values of the operator D=H{psi}/E{psi}-1, characterizing local deviation of the wave function from its true value, in all of the coordinate space in the SVM are consistently larger (by up to five orders of magnitude) than in the CFHHM, despite the fact that the SVM observables except <{delta}(r{sub k})> converge to significantly more digits than the CFHHM observables for their respective selected bases. (c) 2000 The American Physical Society.
Edge states for the Kalmeyer-Laughlin wave function
NASA Astrophysics Data System (ADS)
Herwerth, Benedikt; Sierra, Germán; Tu, Hong-Hao; Cirac, J. Ignacio; Nielsen, Anne E. B.
2015-12-01
We study lattice wave functions obtained from the SU(2)1 Wess-Zumino-Witten conformal field theory. Following Moore and Read's construction, the Kalmeyer-Laughlin fractional quantum Hall state is defined as a correlation function of primary fields. By an additional insertion of Kac-Moody currents, we associate a wave function with each state of the conformal field theory. These wave functions span the complete Hilbert space of the lattice system. On the cylinder, we study global properties of the lattice states analytically and correlation functions numerically using a Metropolis Monte Carlo method. By comparing short-range bulk correlations, numerical evidence is provided that the states with one current operator represent edge states in the thermodynamic limit. We show that the edge states with one Kac-Moody current of lowest order have a good overlap with low-energy excited states of a local Hamiltonian, for which the Kalmeyer-Laughlin state approximates the ground state. For some states, exact parent Hamiltonians are derived on the cylinder. These Hamiltonians are SU(2) invariant and nonlocal with up to four-body interactions.
[Nuclear medicine for evaluation of liver functions].
Yamamoto, K
1994-05-01
The clinical usefulness of colloid liver scintigraphy to detect space occupying lesions in the liver has been reduced by X-ray CT and ultrasonography. However, scintigraphic examinations have potentials for characteristic diagnosis of liver tumors, such as 99mTc RBC SPECT for hepatic hemangioma, 99mTc PMT for positive imaging of hepatocellular carcinoma and its extrahepatic metastasis, and radioimmunoscintigraphy for metastatic tumors. Moreover, prediction of the prognosis and monitoring therapeutic effect to liver cancer can be made by the use of nuclear medicine techniques. Recently, 99mTc galactosyl serum albumin (GSA), a newly developed radiotracer to evaluate hepatocyte function, has become commercially available. Quantitative parameters of liver functions can be obtained by analysis of time-activity curve in blood and liver after 99mTc-GSA administration. In several cases, 99mTc-GSA study showed intrahepatic unevenness of function, which could not be depicted by other imaging examinations. Positron emission tomography (PET) with 18F-fluoro-2-deoxy glucose (FDG) is useful to detect malignant tumors in the liver. Since PET can provide absolutely quantitative data in better resolution, it is expected that regional true metabolic functions in the liver may be able to be quantitatively evaluated with PET in near future. PMID:8028225
Probing the wave function of shallow Li and Na donors in ZnO nanoparticles.
Orlinskii, Serguei B; Schmidt, Jan; Baranov, Pavel G; Hofmann, Detlev M; de Mello Donegá, Celso; Meijerink, Andries
2004-01-30
Electron paramagnetic resonance and electron nuclear double resonance (ENDOR) experiments on ZnO nanoparticles reveal the presence of shallow donors related to interstitial Li and Na atoms. The shallow character of the wave function is evidenced by the multitude of 67Zn ENDOR lines and further by the hyperfine interactions with the 7Li and 23Na nuclei that are much smaller than for atomic lithium and sodium. In the case of the Li-doped nanoparticles, an increase of the hyperfine interaction with the 7Li nucleus and with the 1H nuclei in the Zn(OH)(2) capping layer is observed when reducing the size of the nanoparticles. This effect is caused by the confinement of the shallow-donor 1s-type wave function that has a Bohr radius of about 1.5 nm, i.e., comparable to the dimension of the nanoparticles. PMID:14995405
Probing the Wave Function of Shallow Li and Na Donors in ZnO Nanoparticles
NASA Astrophysics Data System (ADS)
Orlinskii, Serguei B.; Schmidt, Jan; Baranov, Pavel G.; Hofmann, Detlev M.; de Mello Donegá, Celso; Meijerink, Andries
2004-01-01
Electron paramagnetic resonance and electron nuclear double resonance (ENDOR) experiments on ZnO nanoparticles reveal the presence of shallow donors related to interstitial Li and Na atoms. The shallow character of the wave function is evidenced by the multitude of 67Zn ENDOR lines and further by the hyperfine interactions with the 7Li and 23Na nuclei that are much smaller than for atomic lithium and sodium. In the case of the Li-doped nanoparticles, an increase of the hyperfine interaction with the 7Li nucleus and with the 1H nuclei in the Zn(OH)2 capping layer is observed when reducing the size of the nanoparticles. This effect is caused by the confinement of the shallow-donor 1s-type wave function that has a Bohr radius of about 1.5nm, i.e., comparable to the dimension of the nanoparticles.
The Nuclear Energy Density Functional Formalism
NASA Astrophysics Data System (ADS)
Duguet, T.
The present document focuses on the theoretical foundations of the nuclear energy density functional (EDF) method. As such, it does not aim at reviewing the status of the field, at covering all possible ramifications of the approach or at presenting recent achievements and applications. The objective is to provide a modern account of the nuclear EDF formalism that is at variance with traditional presentations that rely, at one point or another, on a Hamiltonian-based picture. The latter is not general enough to encompass what the nuclear EDF method represents as of today. Specifically, the traditional Hamiltonian-based picture does not allow one to grasp the difficulties associated with the fact that currently available parametrizations of the energy kernel E[g',g] at play in the method do not derive from a genuine Hamilton operator, would the latter be effective. The method is formulated from the outset through the most general multi-reference, i.e. beyond mean-field, implementation such that the single-reference, i.e. "mean-field", derives as a particular case. As such, a key point of the presentation provided here is to demonstrate that the multi-reference EDF method can indeed be formulated in a mathematically meaningful fashion even if E[g',g] does not derive from a genuine Hamilton operator. In particular, the restoration of symmetries can be entirely formulated without making any reference to a projected state, i.e. within a genuine EDF framework. However, and as is illustrated in the present document, a mathematically meaningful formulation does not guarantee that the formalism is sound from a physical standpoint. The price at which the latter can be enforced as well in the future is eventually alluded to.
Resonating valence bond wave functions and classical interacting dimer models.
Damle, Kedar; Dhar, Deepak; Ramola, Kabir
2012-06-15
We relate properties of nearest-neighbor resonating valence-bond (NNRVB) wave functions for SU(g) spin systems on two-dimensional bipartite lattices to those of fully packed interacting classical dimer models on the same lattice. The interaction energy can be expressed as a sum of n-body potentials V(n), which are recursively determined from the NNRVB wave function on finite subgraphs of the original lattice. The magnitude of the n-body interaction V(n) (n>1) is of order O(g(-(n-1))) for small g(-1). The leading term is a two-body nearest-neighbor interaction V2(g) favoring two parallel dimers on elementary plaquettes. For SU(2) spins, using our calculated value of V2(g=2), we find that the long-distance behavior of the bond-energy correlation function is dominated by an oscillatory term that decays as 1/|r|α with α≈1.22. This result is in remarkable quantitative agreement with earlier direct numerical studies of the corresponding wave function, which give α≈1.20. PMID:23004328
Estimating Moho depth utilizing S-wave receiver functions
NASA Astrophysics Data System (ADS)
Ceylan, S.; Rychert, C.; Harmon, N.
2014-12-01
H-k stacking method [Zhu and Kanamori, 2000] is a widely used grid search technique for estimating the Moho depth (H) and Vp/Vs (k) beneath a given station. The H-k surface reaches a maximum when the optimum H and k values are used, which is assumed to be the average crustal structure beneath the seismic station. In general, the method is employed in conjunction with P-wave receiver functions. Here, we investigate the usability of H-k stacking method with S-to-P (Sp) conversions and S-wave reverberations within the crust, employing an extended multi-taper deconvolution. We apply the method to southern California, using data recorded between 1990-2011. We compare results with those of prior studies that used P-to-S (Ps) conversions [Zhu and Kanamori, 2000; Yan and Clayton, 2007], applying a smoothing length of 0.5 degrees to reflect lateral Sp sensitivity. P-waves have better potential to resolve lateral variations in Moho depth owing to the higher frequency content and the geometry of Ps ray path. Our results from Sp conversions are in broad agreement with those from Ps, affirming that S-wave receiver functions can be used in conjunction with the H-k stacking method. Consistent with the P-wave receiver function results, crust is thinner beneath the central Transverse Range (30 km) with respect to eastern Transverse Range (33 km) and Peninsular Region (35 km). Our Moho depth observations (35 km) are more compatible with those of Yan and Clayton [2007] (~35 km) than Zhu and Kanamori [2000] (~30 km) beneath Sierra Nevada, most probably due to a larger data set this study and Yan and Clayton [2007] use. Also, results from this study are deeper than those from Ps for the Salton Trough (30-35 km vs. 25 km). In this case, broad receiver function waveform characteristics suggest a more gradual impedance change across the Moho discontinuity and/or a multi-layered crust. We suggest that a combination of P- and S-wave receiver functions can yield more robust crustal thickness
Configuration interaction wave functions: A seniority number approach
Alcoba, Diego R.; Torre, Alicia; Lain, Luis; Massaccesi, Gustavo E.; Oña, Ofelia B.
2014-06-21
This work deals with the configuration interaction method when an N-electron Hamiltonian is projected on Slater determinants which are classified according to their seniority number values. We study the spin features of the wave functions and the size of the matrices required to formulate states of any spin symmetry within this treatment. Correlation energies associated with the wave functions arising from the seniority-based configuration interaction procedure are determined for three types of molecular orbital basis: canonical molecular orbitals, natural orbitals, and the orbitals resulting from minimizing the expectation value of the N-electron seniority number operator. The performance of these bases is analyzed by means of numerical results obtained from selected N-electron systems of several spin symmetries. The comparison of the results highlights the efficiency of the molecular orbital basis which minimizes the mean value of the seniority number for a state, yielding energy values closer to those provided by the full configuration interaction procedure.
Configuration interaction wave functions: A seniority number approach
NASA Astrophysics Data System (ADS)
Alcoba, Diego R.; Torre, Alicia; Lain, Luis; Massaccesi, Gustavo E.; Oña, Ofelia B.
2014-06-01
This work deals with the configuration interaction method when an N-electron Hamiltonian is projected on Slater determinants which are classified according to their seniority number values. We study the spin features of the wave functions and the size of the matrices required to formulate states of any spin symmetry within this treatment. Correlation energies associated with the wave functions arising from the seniority-based configuration interaction procedure are determined for three types of molecular orbital basis: canonical molecular orbitals, natural orbitals, and the orbitals resulting from minimizing the expectation value of the N-electron seniority number operator. The performance of these bases is analyzed by means of numerical results obtained from selected N-electron systems of several spin symmetries. The comparison of the results highlights the efficiency of the molecular orbital basis which minimizes the mean value of the seniority number for a state, yielding energy values closer to those provided by the full configuration interaction procedure.
Hydrodynamic Waves and Correlation Functions in Dusty Plasmas
NASA Astrophysics Data System (ADS)
Bhattacharjee, A.; Wang, Xiaogang
1997-11-01
A hydrodynamic description of strongly coupled dusty plasmas is given when physical quantities vary slowly in space and time and the system can be assumed to be in local thermodynamic equilibrium. The linear waves in such a system are analyzed. In particular, a dispersion equation is derived for low-frequency dust acoustic waves, including collisional damping effects, and compared with experimental results. The linear response of the system is calculated from the fluctuation-dissipation theorem and the hydrodynamic equations. The requirement that these two calculations coincide constrains the particle correlation function for slowly varying perturbations [L. P. Kadanoff and P. C. Martin, Ann. Phys. 24, 419 (1963)]. It is shown that in the presence of the slow dust-acoustic waves, the dust auto-correlation function is of the Debye-Hekel form and the shielding distance is the dust Debye length. In the short-wavelength regime, an integral equation is derived from kinetic theory and solved numerically to yield particle correlation functions that display ``liquid-like'' behavior and have been observed experimentally [R. A.. Quinn, C. Cui, J. Goree, J. B. Pieper, H. Thomas and G. E. Morfill, Phys. Rev. E 53, R2049 (1996)].
Computational aspects of the continuum quaternionic wave functions for hydrogen
Morais, J.
2014-10-15
Over the past few years considerable attention has been given to the role played by the Hydrogen Continuum Wave Functions (HCWFs) in quantum theory. The HCWFs arise via the method of separation of variables for the time-independent Schrödinger equation in spherical coordinates. The HCWFs are composed of products of a radial part involving associated Laguerre polynomials multiplied by exponential factors and an angular part that is the spherical harmonics. In the present paper we introduce the continuum wave functions for hydrogen within quaternionic analysis ((R)QHCWFs), a result which is not available in the existing literature. In particular, the underlying functions are of three real variables and take on either values in the reduced and full quaternions (identified, respectively, with R{sup 3} and R{sup 4}). We prove that the (R)QHCWFs are orthonormal to one another. The representation of these functions in terms of the HCWFs are explicitly given, from which several recurrence formulae for fast computer implementations can be derived. A summary of fundamental properties and further computation of the hydrogen-like atom transforms of the (R)QHCWFs are also discussed. We address all the above and explore some basic facts of the arising quaternionic function theory. As an application, we provide the reader with plot simulations that demonstrate the effectiveness of our approach. (R)QHCWFs are new in the literature and have some consequences that are now under investigation.
Spin-orbit interaction with nonlinear wave functions.
Brozell, S. R.; Shepard, R.; Zhang, Z.; Stanford Univ.
2007-12-01
The computation of the spin-orbit interaction is discussed for electronic wave functions expressed in the new nonlinear expansion form. This form is based on spin eigenfunctions using the graphical unitary group approach (GUGA). The nodes of a Shavitt graph in GUGA are connected by arcs, and a Configuration State Function (CSF) is represented as a walk along arcs from the vacuum node to a head node. The wave function is a linear combination of product functions each of which is a linear combination of all CSFs, wherein each CSF coefficient is a product of nonlinear arc factors. When the spin-orbit interaction is included the Shavitt graph is a union of single-headed Shavitt graphs each with the same total number of electrons and orbitals. Thus spin-orbit Shavitt graphs are multiheaded. For full-CI multiheaded Shavitt graphs, analytic expressions are presented for the number of walks, the number of nodes, the number of arcs, and the number of node pairs in the associated auxiliary pair graph.
Orbital dependent functionals: An atom projector augmented wave method implementation
NASA Astrophysics Data System (ADS)
Xu, Xiao
This thesis explores the formulation and numerical implementation of orbital dependent exchange-correlation functionals within electronic structure calculations. These orbital-dependent exchange-correlation functionals have recently received renewed attention as a means to improve the physical representation of electron interactions within electronic structure calculations. In particular, electron self-interaction terms can be avoided. In this thesis, an orbital-dependent functional is considered in the context of Hartree-Fock (HF) theory as well as the Optimized Effective Potential (OEP) method and the approximate OEP method developed by Krieger, Li, and Iafrate, known as the KLI approximation. In this thesis, the Fock exchange term is used as a simple well-defined example of an orbital-dependent functional. The Projected Augmented Wave (PAW) method developed by P. E. Blochl has proven to be accurate and efficient for electronic structure calculations for local and semi-local functions because of its accurate evaluation of interaction integrals by controlling multiple moments. We have extended the PAW method to treat orbital-dependent functionals in Hartree-Fock theory and the Optimized Effective Potential method, particularly in the KLI approximation. In the course of study we develop a frozen-core orbital approximation that accurately treats the core electron contributions for above three methods. The main part of the thesis focuses on the treatment of spherical atoms. We have investigated the behavior of PAW-Hartree Fock and PAW-KLI basis, projector, and pseudopotential functions for several elements throughout the periodic table. We have also extended the formalism to the treatment of solids in a plane wave basis and implemented PWPAW-KLI code, which will appear in future publications.
Irregular wave functions of a hydrogen atom in a uniform magnetic field
NASA Technical Reports Server (NTRS)
Wintgen, D.; Hoenig, A.
1989-01-01
The highly excited irregular wave functions of a hydrogen atom in a uniform magnetic field are investigated analytically, with wave function scarring by periodic orbits considered quantitatively. The results obtained confirm that the contributions of closed classical orbits to the spatial wave functions vanish in the semiclassical limit. Their disappearance, however, is slow. This discussion is illustrated by numerical examples.
A Critical Examination of Wind-Wave Spectral Functional Form
NASA Technical Reports Server (NTRS)
Huang, Norden E.; Long, Steven R.
1999-01-01
Traditionally, data from random ocean waves are presented in spectral functions. The spectra are the result of Fourier analysis. Fourier spectral analysis has dominated data analysis for, at least, the last hundred years. It has been the standard method for is examining the global amplitude-frequency distributions. Although Fourier transform valid under extremely general conditions, there are some crucial restrictions for the Fourier spectral analysis. The system must be linear, and the data must be stationary- otherwise, the resulting spectrum will make little physical sense. The stationarity requirement is also a common required criterion for most of other available data analysis methods. Nevertheless, few, if any, natural phenomena are linear and stationary. To compound these complications is the imperfection of our probes or numerical schemes the interactions of the imperfect probes even with a perfect linear system can make the final data nonlinear. Furthermore, all the available data are usually of finite duration. Under these conditions, Fourier analysis is of limited use, For lack of alternatives, however, Fourier analysis is still used to process such data. The loose application of Fourier analysis and the insouciant adoption of the stationary and linear assumptions may lead to misleading conclusions. Ocean waves are know to be nonlinear, and the wind system generating the wave field are seldom stationary- As a result, the traditional examination of the spectral form hardly made physical sense. A new method for analyzing nonlinear and nonstationary data has been developed. The key part is the Empirical Mode Decomposition (EMD) method with which any complicated data set can be decomposed into a finite and often small number of Intrinsic Mode Functions (IMF) that serve as the basis of the representation of the data, This decomposition method is adaptive, and, therefore, highly efficient. The IMFs admit well-behaved Hilbert transforms, and yield instantaneous
Li, Yong; Fang, Hui; Min, Changjun; Yuan, Xiaocong
2015-01-01
Under the usual approximation of treating a biological particle as a spheroidal droplet, we consider the analysis of its size and shape with the high frequency photoacoustics and develop a numerical method which can simulate its characteristic photoacoustic waves. This numerical method is based on the calculation of spheroidal wave functions, and when comparing to the finite element model (FEM) calculation, can reveal more physical information and can provide results independently at each spatial points. As the demonstration, red blood cells (RBCs) and MCF7 cell nuclei are studied, and their photoacoustic responses including field distribution, spectral amplitude, and pulse forming are calculated. We expect that integrating this numerical method with the high frequency photoacoustic measurement will form a new modality being extra to the light scattering method, for fast assessing the morphology of a biological particle. PMID:26442830
Numerical simulations of blast/shock wave propagations after nuclear explosions
NASA Astrophysics Data System (ADS)
Song, Seungho; Choi, Jung-Il; Li, Yibao; Lee, Changhoon
2013-11-01
Pressure waves develop immediately after nuclear explosions and start to move outward from the fireball. The most of initial damages are caused by the blast waves. We performed the blast wave propagations by solving two-dimensional and axisymmetric Euler equations. For shock capturing, inviscid fluxes are discretized using a variant of the piecewise parabolic method (PPM) and an approximate Riemann solver based on Roe's method is used. A clean air burst of fireball above the ground zero is considered. The initial condition of fireball is given at the point of breakaway that shock waves are appeared on the surface of the fireball. The growth of fireball is also calculated by solving one-dimensional radiation hydrodynamics (RHD) equation from point explosion. Characteristics of the blast wave propagations due to the various heights of burst and amount of the nuclear detonations are investigated. The results of parametric studies will be shown in the final presentation. Supported by Agency for Defense Development.
Is spontaneous wave function collapse testable at all?
NASA Astrophysics Data System (ADS)
Diósi, Lajos
2015-07-01
Mainstream literature on spontaneous wave function collapse never reflects on or profits from the formal coincidence and conceptual relationship with standard collapse under time-continuous quantum measurement (monitoring). I propose some easy lessons of standard monitoring theory which would make spontaneous collapse models revise some of their claims. In particular, the objective detection of spontaneous collapse remains impossible as long as the correct identification of what corresponds to the signal in standard monitoring is missing from spontaneous collapse models, the physical detectability of the “signal” is not stated explicitly and, finally, the principles of physical detection are not revealed.
Standard quantum mechanics featuring probabilities instead of wave functions
Manko, V. I. Manko, O. V.
2006-06-15
A new formulation of quantum mechanics (probability representation) is discussed. In this representation, a quantum state is described by a standard positive definite probability distribution (tomogram) rather than by a wave function. An unambiguous relation (analog of Radon transformation) between the density operator and a tomogram is constructed both for continuous coordinates and for spin variables. A novel feature of a state, tomographic entropy, is considered, and its connection with von Neumann entropy is discussed. A one-to-one map of quantum observables (Hermitian operators) on positive probability distributions is found.
Chameleon fields, wave function collapse and quantum gravity
NASA Astrophysics Data System (ADS)
Zanzi, A.
2015-07-01
Chameleon fields are quantum (usually scalar) fields, with a density-dependent mass. In a high-density environment, the mass of the chameleon is large. On the contrary, in a small-density environment (e.g. on cosmological distances), the chameleon is very light. A model where the collapse of the wave function is induced by chameleon fields is presented. During this analysis, a Chameleonic Equivalence Principle (CEP) will be formulated: in this model, quantum gravitation is equivalent to a conformal anomaly. Further research efforts are necessary to verify whether this proposal is compatible with phenomeno logical constraints.
Average wave function method for gas-surface scattering
NASA Astrophysics Data System (ADS)
Singh, Harjinder; Dacol, Dalcio K.; Rabitz, Herschel
1986-02-01
The average wave function method (AWM) is applied to scattering of a gas off a solid surface. The formalism is developed for both periodic as well as disordered surfaces. For an ordered lattice an explicit relation is derived for the Bragg peaks along with a numerical illustration. Numerical results are presented for atomic clusters on a flat hard wall with a Gaussian-like potential at each atomic scattering site. The effect of relative lateral displacement of two clusters upon the scattering pattern is shown. The ability of AWM to accommodate disorder through statistical averaging over cluster configurations is illustrated. Enhanced uniform backscattering is observed with increasing roughness on the surface.
Horizon wave-function and the quantum cosmic censorship
NASA Astrophysics Data System (ADS)
Casadio, Roberto; Micu, Octavian; Stojkovic, Dejan
2015-07-01
We investigate the Cosmic Censorship Conjecture by means of the horizon wave-function (HWF) formalism. We consider a charged massive particle whose quantum mechanical state is represented by a spherically symmetric Gaussian wave-function, and restrict our attention to the superextremal case (with charge-to-mass ratio α > 1), which is the prototype of a naked singularity in the classical theory. We find that one can still obtain a normalisable HWF for α2 < 2, and this configuration has a non-vanishing probability of being a black hole, thus extending the classically allowed region for a charged black hole. However, the HWF is not normalisable for α2 > 2, and the uncertainty in the location of the horizon blows up at α2 = 2, signalling that such an object is no more well-defined. This perhaps implies that a quantum Cosmic Censorship might be conjectured by stating that no black holes with charge-to-mass ratio greater than a critical value (of the order of √{ 2}) can exist.
Wave functions for fractional Chern insulators in disk geometry
NASA Astrophysics Data System (ADS)
He, Ai-Lei; Luo, Wei-Wei; Wang, Yi-Fei; Gong, Chang-De
2015-12-01
Recently, fractional Chern insulators (FCIs), also called fractional quantum anomalous Hall (FQAH) states, have been theoretically established in lattice systems with topological flat bands. These systems exhibit similar fractionalization phenomena to the conventional fractional quantum Hall (FQH) systems. Using the mapping relationship between the FQH states and the FCI/FQAH states, we construct the many-body wave functions of the fermionic FCI/FQAH states in disk geometry with the aid of the generalized Pauli principle (GPP) and Jack polynomials. Compared with the ground state by the exact diagonalization method, the wave-function overlap is higher than 0.97, even when the Hilbert space dimension is as large as 3 × 106. We also use the GPP and the Jack polynomials to construct edge excitations for the fermionic FCI/FQAH states. The quasi-degeneracy sequences of fermionic FCI/FQAH systems reproduce the prediction of the chiral Luttinger liquid theory, complementing the exact diagonalization results with larger lattice sizes and more particles.
Dynamics of nuclear wave packets at the F center in alkali halides
NASA Astrophysics Data System (ADS)
Koyama, Takeshi; Suemoto, Tohru
2011-07-01
The F center in alkali halides is a well-known prototype of a strongly coupled localized electron-phonon system. This colour center is one of the long studied targets in the field of photophysics because it is simple but rich in variety. Steady-state spectroscopy, such as modulation spectroscopy and Raman scattering spectroscopy, has elucidated the strength of the electron-phonon coupling in the (meta-)stable state, i.e. the ground state and the relaxed excited state. Picosecond spectroscopy has improved understanding of the state mixing in the transient state. Owing to recent developments of ultrafast lasers with pulse widths shorter than oscillation periods of phonons, it has been possible to perform real-time observation of lattice vibration, and the understanding of the transient state has been remarkably expanded. In this paper, we review early and present studies on dynamics of electron-phonon coupling at the F center, especially recent real-time observations on the dynamics of nuclear wave packets in the excited state of the F center in KI, KBr, KCl and RbCl. These real-time observations reveal (i) spatial extension of the electronic wave function of a trapped electron, (ii) the difference between the coupled phonons in the ground state and the excited state, (iii) diabatic transition between the adiabatic potential energy surfaces and (iv) anharmonicity of the potential energy surface.
Puster, P.; Jordan, T.H.
1996-11-20
We apply methods for the recovery of the frequency dependent moment rate tensor, M(w), to the study of Lop Nor nuclear explosions. This approach encompasses many source parameter diagnostics that have been traditionally used to discriminate nuclear explosions from chemical explosions and earthquakes and has the potential to provide new discrimination tools. We parameterize the source as M(w) = M1(a) + MD(a), where M1(co) and MD(O) are isotropic and deviatoric components, respectively. Our goal is to quantify both isotropic and deviatoric components, and investigate the different contributions to MD(a), in particular the tectonic release. Since tectonic release can bias estimates of M1(o) and may limit discrimination capabilities of sparse networks, it is important to be able to characterize the amount of tectonic release - in particular as a function of frequency. Our approach uses synthetic seismograms to improve the localization of signal measurements in both time and frequency domains. We adapt our earthquake-source inversion algorithms to account for isotropic sources at very shallow depths. We test our algorithms using a synthetic case with a known moment-tensor source composed in equal parts of isotropic and deviatoric sources; we successfully recover both MD and M using body waves and surface waves on horizontal and vertical components. We apply our methods to a data set containing both SH and Love waves as well as the body-wave portion between P and R1 and the minor-arc Rayleigh waves from the 92/5/21 Chinese nuclear test. We recover a significant tectonic release component for this event; the deviatoric moment tensor is a dip-slip reverse fault with a scalar moment MD = 1.9 +/- 0.2 x 10(17) Nm. The strike of the best-fitting double-couple is 320 deg. The source-time function derived from SH-polarized waves shows some complexity, with a sharp pulse i.
Goal direction and effectiveness, emotional maturity, and nuclear family functioning.
Klever, Phillip
2009-07-01
Differentiation of self, a cornerstone concept in Bowen theory, has a profound influence over time on the functioning of the individual and his or her family unit. This 5-year longitudinal study tested this hypothesis with 50 developing nuclear families. The dimensions of differentiation of self that were examined were goal direction and effectiveness and emotional maturity. A qualitative analysis of participants' goals demonstrated that couples with higher functioning developing nuclear families, when compared with couples with lower functioning families, placed more emphasis on family goals, had more balance between family and personal goals, and pursued more goals over the 5 years. The quantitative analysis supported the hypothesis that goal effectiveness and emotional maturity influenced variation in nuclear family functioning. In addition, couple goal effectiveness and emotional maturity were associated with nuclear family functioning more strongly than individual goal effectiveness and emotional maturity were associated with individual functioning. PMID:19522784
Quantification of Uncertainties in Nuclear Density Functional Theory
Schunck, N.; McDonnell, J.D.; Higdon, D.; Sarich, J.; Wild, S.
2015-01-15
Reliable predictions of nuclear properties are needed as much to answer fundamental science questions as in applications such as reactor physics or data evaluation. Nuclear density functional theory is currently the only microscopic, global approach to nuclear structure that is applicable throughout the nuclear chart. In the past few years, a lot of effort has been devoted to setting up a general methodology to assess theoretical uncertainties in nuclear DFT calculations. In this paper, we summarize some of the recent progress in this direction. Most of the new material discussed here will be be published in separate articles.
Nuclear reactions in shock wave front during supernova events
NASA Technical Reports Server (NTRS)
Lavrukhina, A. K.
1985-01-01
The new unique isotopic anomalous coponent of Xe(XeX) was found in the carbonaceous chondrites. It is enriched in light shielded isotopes (124Xe and 126Xe) and in heavy nonshielded isotopes (134Xe and 136Xe. All characteristics of Xe-X can be explained by a model of nucleosynthesis of the Xe isotopes in shock wave front passed through the He envelope during supernova events. The light isotopes are created by p process and the heavy isotopes are created by n process (slow r process). They were captured with high temperature carbon grains condensing by supernova shock waves.
NASA Astrophysics Data System (ADS)
Sokolova, Inna
2015-04-01
Availability of the acoustic wave on the record of microbarograph is one of discriminate signs of atmospheric (surface layer of atmosphere) and contact explosions. Nowadays there is large number of air wave records from chemical explosions recorded by the IMS infrasound stations installed during recent decade. But there is small number of air wave records from nuclear explosions as air and contact nuclear explosions had been conducted since 1945 to 1962, before the Limited Test Ban Treaty was signed in 1963 (the treaty banning nuclear weapon tests in the atmosphere, in outer space and under water) by the Great Britain, USSR and USA. That time there was small number of installed microbarographs. First infrasound stations in the USSR appeared in 1954, and by the moment of the USSR collapse the network consisted of 25 infrasound stations, 3 of which were located on Kazakhstan territory - in Kurchatov (East Kazakhstan), in Borovoye Observatory (North Kazakhstan) and Talgar Observatory (Northern Tien Shan). The microbarograph of Talgar Observatory was installed in 1962 and recorded large number of air nuclear explosions conducted at Semipalatinsk Test Site and Novaya Zemlya Test Site. The epicentral distance to the STS was ~700 km, and to Novaya Zemlya Test Site ~3500 km. The historical analog records of the microbarograph were analyzed on the availability of the acoustic wave. The selected records were digitized, the database of acoustic signals from nuclear explosions was created. In addition, acoustic signals from atmospheric nuclear explosions conducted at the USSR Test Sites were recorded by analogue broadband seismic stations at wide range of epicentral distances, 300-3600 km. These signals coincide well by its form and spectral content with records of microbarographs and can be used for monitoring tasks and discrimination in places where infrasound observations are absent. Nuclear explosions which records contained acoustic wave were from 0.03 to 30 kt yield for
Magnetospheric electron-velocity-distribution function information from wave observations
NASA Astrophysics Data System (ADS)
Benson, Robert F.; ViñAs, Adolfo F.; Osherovich, Vladimir A.; Fainberg, Joseph; Purser, Carola M.; Adrian, Mark L.; Galkin, Ivan A.; Reinisch, Bodo W.
2013-08-01
The electron-velocity-distribution function was determined to be highly non-Maxwellian and more appropriate to a kappa distribution, with κ ≈ 2.0, near magnetic midnight in the low-latitude magnetosphere just outside a stable plasmasphere during extremely quiet geomagnetic conditions. The kappa results were based on sounder-stimulated Qn plasma resonances using the Radio Plasma Imager (RPI) on the IMAGE satellite; the state of the plasmasphere was determined from IMAGE/EUV observations. The Qn resonances correspond to the maximum frequencies of Bernstein-mode waves that are observed between the harmonics of the electron cyclotron frequency in the frequency domain above the upper-hybrid frequency. Here we present the results of a parametric investigation that included suprathermal electrons in the electron-velocity-distribution function used in the plasma-wave dispersion equation to calculate the Qn frequencies for a range of kappa and fpe/fce values for Qn resonances from Q1 to Q9. The Qn frequencies were also calculated using a Maxwellian distribution, and they were found to be greater than those calculated using a kappa distribution with the frequency differences increasing with increasing n for a fixed κ and with decreasing κ for a fixed n. The calculated fQn values have been incorporated into the RPI BinBrowser software providing a powerful tool for rapidly obtaining information on the nature of the magnetospheric electron-velocity-distribution function and the electron number density Ne. This capability enabled accurate (within a few percent) in situ Ne determinations to be made along the outbound orbital track as IMAGE moved away from the plasmapause. The extremely quiet geomagnetic conditions allowed IMAGE/EUV-extracted counts to be compared with the RPI-determined orbital-track Ne profile. The comparisons revealed remarkably similar Ne structures.
Magnetospheric Electron-Velocity-Distribution Function Information from Wave Observations
NASA Astrophysics Data System (ADS)
Benson, R. F.; Vinas, A. F.; Osherovich, V. A.; Fainberg, J.; Purser, C. M.; Adrian, M. L.; Galkin, I. A.; Reinisch, B. W.
2013-12-01
The electron-velocity-distribution function was determined to be highly non-Maxwellian and more appropriate to a kappa distribution, with κ ≈ 2.0, near magnetic midnight in the low-latitude magnetosphere just outside a stable plasmasphere during extremely quiet geomagnetic conditions. The kappa results were based on sounder-stimulated Qn plasma resonances using the Radio Plasma Imager (RPI) on the IMAGE satellite; the state of the plasmasphere was determined from IMAGE/EUV observations. The Qn resonances correspond to the maximum frequencies of Bernstein-mode waves that are observed between the harmonics of the electron cyclotron frequency in the frequency domain above the upper-hybrid frequency. Here we present the results of a parametric investigation that included suprathermal electrons in the electron-velocity-distribution function used in the plasma-wave dispersion equation to calculate the Qn frequencies for a range of kappa and fpe/fce values for Qn resonances from Q1 to Q9. The Qn frequencies were also calculated using a Maxwellian distribution and they were found to be greater than those calculated using a kappa distribution with the frequency differences increasing with increasing n for a fixed κ and with decreasing κ for a fixed n. The calculated fQn values have been incorporated into the RPI BinBrowser software providing a powerful tool for rapidly obtaining information on the nature of the magnetospheric electron-velocity-distribution function and the electron number density Ne. This capability enabled accurate (within a few percent) in-situ Ne determinations to be made along the outbound orbital track as IMAGE moved away from the plasmapause. The extremely quiet geomagnetic conditions allowed IMAGE/EUV-extracted counts to be compared with the RPI-determined orbital-track Ne profile. The comparisons revealed remarkably similar Ne structures.
Nuclear collective excitations: A relativistic density functional approach
NASA Astrophysics Data System (ADS)
Piekarewicz, J.
2015-08-01
Density functional theory provides the most promising, and likely unique, microscopic framework to describe nuclear systems ranging from finite nuclei to neutron stars. Properly optimized energy density functionals define a new paradigm in nuclear theory where predictive capability is possible and uncertainty quantification is demanded. Moreover, density functional theory offers a consistent approach to the linear response of the nuclear ground state. In this paper, we review the fundamental role played by nuclear collective modes in uncovering novel excitations and in guiding the optimization of the density functional. Indeed, without collective excitations the determination of the density functional remains incomplete. Without collective excitations, the equation of state of neutron-rich matter continues to be poorly constrained. We conclude with a discussion of some of the remaining challenges in this field and propose a path forward to address these challenges.
Tissue specificity in the nuclear envelope supports its functional complexity
de las Heras, Jose I; Meinke, Peter; Batrakou, Dzmitry G; Srsen, Vlastimil; Zuleger, Nikolaj; Kerr, Alastair RW; Schirmer, Eric C
2013-01-01
Nuclear envelope links to inherited disease gave the conundrum of how mutations in near-ubiquitous proteins can yield many distinct pathologies, each focused in different tissues. One conundrum-resolving hypothesis is that tissue-specific partner proteins mediate these pathologies. Such partner proteins may have now been identified with recent proteome studies determining nuclear envelope composition in different tissues. These studies revealed that the majority of the total nuclear envelope proteins are tissue restricted in their expression. Moreover, functions have been found for a number these tissue-restricted nuclear envelope proteins that fit with mechanisms proposed to explain how the nuclear envelope could mediate disease, including defects in mechanical stability, cell cycle regulation, signaling, genome organization, gene expression, nucleocytoplasmic transport, and differentiation. The wide range of functions to which these proteins contribute is consistent with not only their involvement in tissue-specific nuclear envelope disease pathologies, but also tissue evolution. PMID:24213376
Human brain networks function in connectome-specific harmonic waves
Atasoy, Selen; Donnelly, Isaac; Pearson, Joel
2016-01-01
A key characteristic of human brain activity is coherent, spatially distributed oscillations forming behaviour-dependent brain networks. However, a fundamental principle underlying these networks remains unknown. Here we report that functional networks of the human brain are predicted by harmonic patterns, ubiquitous throughout nature, steered by the anatomy of the human cerebral cortex, the human connectome. We introduce a new technique extending the Fourier basis to the human connectome. In this new frequency-specific representation of cortical activity, that we call ‘connectome harmonics', oscillatory networks of the human brain at rest match harmonic wave patterns of certain frequencies. We demonstrate a neural mechanism behind the self-organization of connectome harmonics with a continuous neural field model of excitatory–inhibitory interactions on the connectome. Remarkably, the critical relation between the neural field patterns and the delicate excitation–inhibition balance fits the neurophysiological changes observed during the loss and recovery of consciousness. PMID:26792267
Semiclassical-wave-function perspective on high-harmonic generation
NASA Astrophysics Data System (ADS)
Mauger, François; Abanador, Paul M.; Lopata, Kenneth; Schafer, Kenneth J.; Gaarde, Mette B.
2016-04-01
We introduce a semiclassical-wave-function (SCWF) model for strong-field physics and attosecond science. When applied to high-harmonic generation (HHG), this formalism allows one to show that the natural time-domain separation of the contribution of ionization, propagation, and recollisions to the HHG process leads to a frequency-domain factorization of the harmonic yield into these same contributions, for any choice of atomic or molecular potential. We first derive the factorization from the natural expression of the dipole signal in the temporal domain by using a reference system, as in the quantitative rescattering (QRS) formalism [J. Phys. B 43, 122001 (2010), 10.1088/0953-4075/43/12/122001]. Alternatively, we show how the trajectory component of the SCWF can be used to express the factorization, which also allows one to attribute individual contributions to the spectrum to the underlying trajectories.
Source function and plane waves: Toward complete bader analysis.
Tantardini, Christian; Ceresoli, Davide; Benassi, Enrico
2016-09-01
The source function (SF) is a topological descriptor that was introduced and developed by C. Gatti and R.W. Bader in 1998. The SF describes the contribution of each atom to the total electron density at a given point. To date, this descriptor has only been calculable from electron densities generated by all-electron (AE) methods for the investigation of single molecules or periodic systems. This study broadens the accessibility of the SF, offering its calculation from electron densities generated by plane wave (PW) methods. The new algorithm has been implemented in the open source code, CRITIC2. Our novel approach has been validated on a series of test systems, comparing the results obtained at PW level with those previously obtained through AE methods. © 2016 Wiley Periodicals, Inc. PMID:27364862
NASA Astrophysics Data System (ADS)
Hong, T.-K.
2009-04-01
Understanding the shear-wave excitation mechanism is a key issue for effective seismic monitoring of underground nuclear explosions (UNEs). We often observe strong shear waves from UNEs, which causes difficulty in prompt discrimination of nuclear explosions from natural earthquakes. Various mechanisms have been proposed to explain the shear-wave excitation from the UNEs. Consensus on dominant mechanism of shear-wave excitation has not been made. To constrain the shear-wave excitation mechanism, we examine the consistency in shear-wave radiation pattern using a source-array slowness-wavenumber (F-K) analysis, which allows us to check the time-invariant feature in the shear waves. We examine regional and teleseismic waveforms for the UNEs of the Balapan test site and Nevada test site along with the Indian and North Korean UNEs. We observe consistent radiation pattern in both regional and teleseismic shear waves. The observed radiation pattern suggests that the shear waves were not excited azimuthally-isotropic. Shear waves observed in teleseismic distances are far weak compared to those in regional distances, which implies that shear waves are excited stronger at high takeoff angles. Also, spectra of shear waves display significantly low overshoot feature that is different from those of P phases. The time-invariant anisotropic radiation pattern, strong excitation in high takeoff angle and low overshoot feature allow us to constrain the shear-wave excitation mechanism.
Impact of permeability on seismoelectric transfer function of P waves
NASA Astrophysics Data System (ADS)
Holzhauer, J.; Bordes, C.; Oppermann, F.; Brito, D.; Yaramanci, U.
2012-04-01
Recent developments in the understanding of seismoelectrics have shown its potential relevance for porous media characterization with particular focus on permeability estimations. According to promising theoretical and numerical studies, permeability should influence the seismoelectric transfer function at higher frequencies. The dynamic seismoelectric transfer function E(ω)/ ü(ω), where E relates to the coseismic electric field induced by the seismic particle acceleration ü, is expected to increase with increasing permeabilities when crossing the Biot transition frequency. Still, only few experiments have been developed on that matter so far. To address the transfer function dependence on permeability, we adapted a column experiment to comply with steady-state permeability estimations. These observations were run in-situ, during the fluid-balancing phase prior to seismoelectric measurements. The 50 cm-long column had previously been carefully filled with perfectly rounded glass beads. The use of sorted glass beads is expected to achieve similar porosities reproducible throughout the experiment, opposed to varying permeabilities depending on the introduced particle size. The acoustic source delivered compressional waves with an optimal effect limited to the [1-3] kHz frequency range. These limitations are due to strong seismic attenuation in uncompacted porous media on one side, and to the dilemma of observing propagation in downsized laboratory setup on the other. First results validated the experimental protocol in terms of porosity/permeability independence: for particle size varying between 100 μm and 500 μm, permeability varied by a factor 20, with a maximum by 5.10-11 m2, while porosity remained by 39 ± 2 % during the whole experiment. Further investigations are being led regarding the normalised transfer function, corrected for both the fluid conductivity and the seismic energy. For that purpose, we compare the dependence of our measured transfer
Study on far field wave patterns and their characteristics of Havelock form green function
NASA Astrophysics Data System (ADS)
Xu, Yong; Dong, Wen-cai; Xiao, Wen-bin
2013-06-01
A new mathematical integral representation including five integrals about the far field wave shape function of Havelock form translating-pulsating source is obtained by performing variable substitution. Constant-phase curves and propagation wave patterns are investigated by applying stationary phase analysis method to the new representation. Some findings are summarized as follows: (1) when 0< τ <0.25 (where τ is the Strouhal number), three types of stationary phase curves corresponding to three propagation wave patterns such as fan wave pattern, inner V and outer V wave patterns, are found in the integral representation. (2) When τ>0.25, besides three types of wave patterns such as a ring-faning wave pattern, a fan wave pattern and an inner V wave pattern, a new one called parallel wave pattern is also found which not only exists in the integrals about the ring-fan wave and fan wave, but also in the integrals whose interval is [0, γ] In addition, Characteristics about these parallel waves such as mathematical expressions, existence conditions, propagation directions and wave lengths are obtained, and cancellation relationships between these parallel waves are stated, which certificates the fact that there are no parallel waves existing in the far field.
Bohmian Conditional Wave Functions (and the status of the quantum state)
NASA Astrophysics Data System (ADS)
Norsen, Travis
2016-03-01
The de Broglie - Bohm pilot-wave theory - uniquely among realistic candidate quantum theories - allows a straightforward and simple definition of the wave function of a subsystem of some larger system (such as the entire universe). Such sub-system wave functions are called “Conditional Wave Functions” (CWFs). Here we explain this concept and indicate the CWF's role in the Bohmian explanation of the usual quantum formalism, and then develop (and motivate) the more speculative idea that something like single-particle wave functions could replace the (ontologically problematical) universal wave function in some future, empirically adequate, pilot-wave-type theory. Throughout the presentation is pedagogical and points are illustrated with simple toy models.
Nonlocal density-functional description constructed from a correlated many-body wave function
NASA Astrophysics Data System (ADS)
Umezawa, Naoto; Tsuneyuki, Shinji
2004-03-01
We suggest a new approach to the nonlocal density-functional theory. In our method, the nonlocal correlation functional is derived from a correlated many-body wave function using the transcorrelated similarity transformation [1,2]. Our formalism is rigorous in principle if the v-representable density is assumed. In practice, Jastrow-Slater-type wave function is adopted and the correlation functional consists of many-body interactions originated from the Jastrow factor. Instead of struggling with these higher order interactions, we retain only 2-body interactions multiplying an adjusting parameter so that it can reproduce the exact correlation energy for the homogeneous electron gas. Therefore, the computational cost is comparable to the exact exchange method. Moreover, parameters in the Jastrow factor are determined by the two conditions: the cusp conditions and the random-phase approximation without empirical fitting. We found that our correlation functional gives fairly good results for small atoms and ions (He, Li^+, Be^2+, Li, and Be). [1]S. F. Boys and N. C. Handy, Proc. Roy. Soc. A, 309, 209; 310, 43; 310, 63; 311, 309. [2] N. Umezawa and S. Tsuneyuki, J. Chem. Phys. 119, 10015 (2003).
Variational Approach to Yang-Mills Theory with non-Gaussian Wave Functionals
NASA Astrophysics Data System (ADS)
Campagnari, Davide R.; Reinhardt, Hugo
2011-05-01
A general method for treating non-Gaussian wave functionals in quantum field theory is presented and applied to the Hamiltonian approach to Yang-Mills theory in Coulomb gauge in order to include a three-gluon kernel in the exponential of the vacuum wave functional. The three-gluon vertex is calculated using the propagators found in the variational approach with a Gaussian trial wave functional as input.
Riemann {zeta} function from wave-packet dynamics
Mack, R.; Schleich, W. P.; Dahl, J. P.; Moya-Cessa, H.; Strunz, W. T.; Walser, R.
2010-09-15
We show that the time evolution of a thermal phase state of an anharmonic oscillator with logarithmic energy spectrum is intimately connected to the generalized Riemann {zeta} function {zeta}(s,a). Indeed, the autocorrelation function at a time t is determined by {zeta}({sigma}+i{tau},a), where {sigma} is governed by the temperature of the thermal phase state and {tau} is proportional to t. We use the JWKB method to solve the inverse spectral problem for a general logarithmic energy spectrum; that is, we determine a family of potentials giving rise to such a spectrum. For large distances, all potentials display a universal behavior; they take the shape of a logarithm. However, their form close to the origin depends on the value of the Hurwitz parameter a in {zeta}(s,a). In particular, we establish a connection between the value of the potential energy at its minimum, the Hurwitz parameter and the Maslov index of JWKB. We compare and contrast exact and approximate eigenvalues of purely logarithmic potentials. Moreover, we use a numerical method to find a potential which leads to exact logarithmic eigenvalues. We discuss possible realizations of Riemann {zeta} wave-packet dynamics using cold atoms in appropriately tailored light fields.
Assessing the orbital selective Mott transition with variational wave functions
NASA Astrophysics Data System (ADS)
Tocchio, Luca F.; Arrigoni, Federico; Sorella, Sandro; Becca, Federico
2016-03-01
We study the Mott metal-insulator transition in the two-band Hubbard model with different hopping amplitudes t 1 and t 2 for the two orbitals on the two-dimensional square lattice by using non-magnetic variational wave functions, similarly to what has been considered in the limit of infinite dimensions by dynamical mean-field theory. We work out the phase diagram at half filling (i.e. two electrons per site) as a function of R={{t}2}/{{t}1} and the on-site Coulomb repulsion U, for two values of the Hund’s coupling J = 0 and J/U = 0.1. Our results are in good agreement with previous dynamical mean-field theory calculations, demonstrating that the non-magnetic phase diagram is only slightly modified from infinite to two spatial dimensions. Three phases are present: a metallic one, for small values of U, where both orbitals are itinerant; a Mott insulator, for large values of U, where both orbitals are localized because of the Coulomb repulsion; and the so-called orbital-selective Mott insulator (OSMI), for small values of R and intermediate Us, where one orbital is localized while the other one is still itinerant. The effect of the Hund’s coupling is two-fold: on one side, it favors the full Mott phase over the OSMI; on the other side, it stabilizes the OSMI at larger values of R.
Decommissioning nuclear power plants - the wave of the future
Griggs, F.S. Jr.
1994-12-31
The paper discusses the project controls developed in the decommissioning of a nuclear power plant. Considerations are given to the contaminated piping and equipment that have to be removed and the spent and used fuel that has to be disposed of. The storage issue is of primary concern here. The cost control aspects and the dynamics of decommissioning are discussed. The effects of decommissioning laws on the construction and engineering firms are mentioned. 5 refs.
Wave function for time-dependent harmonically confined electrons in a time-dependent electric field.
Li, Yu-Qi; Pan, Xiao-Yin; Sahni, Viraht
2013-09-21
The many-body wave function of a system of interacting particles confined by a time-dependent harmonic potential and perturbed by a time-dependent spatially homogeneous electric field is derived via the Feynman path-integral method. The wave function is comprised of a phase factor times the solution to the unperturbed time-dependent Schrödinger equation with the latter being translated by a time-dependent value that satisfies the classical driven equation of motion. The wave function reduces to that of the Harmonic Potential Theorem wave function for the case of the time-independent harmonic confining potential. PMID:24070284
NASA Astrophysics Data System (ADS)
Ritboon, Atirach; Daengngam, Chalongrat; Pengpan, Teparksorn
2016-08-01
Biakynicki-Birula introduced a photon wave function similar to the matter wave function that satisfies the Schrödinger equation. Its second quantization form can be applied to investigate nonlinear optics at nearly full quantum level. In this paper, we applied the photon wave function formalism to analyze both linear optical processes in the well-known Mach-Zehnder interferometer and nonlinear optical processes for sum-frequency generation in dispersive and lossless medium. Results by photon wave function formalism agree with the well-established Maxwell treatments and existing experimental verifications.
THz-waves channeling in a monolithic saddle-coil for Dynamic Nuclear Polarization enhanced NMR.
Macor, A; de Rijk, E; Annino, G; Alberti, S; Ansermet, J-Ph
2011-10-01
A saddle coil manufactured by electric discharge machining (EDM) from a solid piece of copper has recently been realized at EPFL for Dynamic Nuclear Polarization enhanced Nuclear Magnetic Resonance experiments (DNP-NMR) at 9.4 T. The corresponding electromagnetic behavior of radio-frequency (400 MHz) and THz (263 GHz) waves were studied by numerical simulation in various measurement configurations. Moreover, we present an experimental method by which the results of the THz-wave numerical modeling are validated. On the basis of the good agreement between numerical and experimental results, we conducted by numerical simulation a systematic analysis on the influence of the coil geometry and of the sample properties on the THz-wave field, which is crucial in view of the optimization of DNP-NMR in solids. PMID:21903436
THz-waves channeling in a monolithic saddle-coil for Dynamic Nuclear Polarization enhanced NMR
NASA Astrophysics Data System (ADS)
Macor, A.; de Rijk, E.; Annino, G.; Alberti, S.; Ansermet, J.-Ph.
2011-10-01
A saddle coil manufactured by electric discharge machining (EDM) from a solid piece of copper has recently been realized at EPFL for Dynamic Nuclear Polarization enhanced Nuclear Magnetic Resonance experiments (DNP-NMR) at 9.4 T. The corresponding electromagnetic behavior of radio-frequency (400 MHz) and THz (263 GHz) waves were studied by numerical simulation in various measurement configurations. Moreover, we present an experimental method by which the results of the THz-wave numerical modeling are validated. On the basis of the good agreement between numerical and experimental results, we conducted by numerical simulation a systematic analysis on the influence of the coil geometry and of the sample properties on the THz-wave field, which is crucial in view of the optimization of DNP-NMR in solids.
The Surface Wave Magnitude for the 9 October 2006 North Korean Nuclear Explosion
Bonner, J; Herrmann, R; Harkrider, D; Pasyanos, M
2008-03-11
Surface waves were generated by the North Korean nuclear explosion of 9 October 2006 and recorded at epicentral distances up to 34 degrees, from which we estimated a surface wave magnitude (M{sub s}) of 2.94 with an interstation standard deviation of 0.17 magnitude units. The International Data Centre estimated a body wave magnitude (m{sub b}) of 4.1. This is the only explosion we have analyzed that was not easily screened as an explosion based on the differences between the M{sub s} and m{sub b} estimates. Additionally, this M{sub s} predicts a yield, based on empirical M{sub s}/Yield relationships, that is almost an order of magnitude larger then the 0.5 to 1 kiloton reported for this explosion. We investigate how emplacement medium effects on surface wave moment and magnitude may have contributed to the yield discrepancy.
Oscarsson, T.E.; Roennmark, K.G. )
1990-12-01
In this paper the authors present an investigation of low-frequency waves observed on auroral field lines below the acceleration region by the Swedish satellite Viking. The measured frequency spectra are peaked at half the local proton gyrofrequency, and the waves are observed in close connection with precipitating electrons. In order to obtain information about the distribution of wave energy in wave vector space, they reconstruct the wave distribution function (WDF) from observed spectral densities. They use a new scheme that allows them to reconstruct simultaneously the WDF over a broad frequency band. The method also makes it possible to take into account available particle observations as well as Doppler shifts caused by the relative motion between the plasma and the satellite. The distribution of energy in wave vector space suggested by the reconstructed WDF is found to be consistent with what is expected from a plasma instability driven by the observed precipitating electrons. Furthermore, by using UV images obtained on Viking, they demonstrate that the wave propagation directions indicated by the reconstructed WDFs are consistent with a simple model of the presumed wave source in the electron precipitation region.
Spin constraints on nuclear energy density functionals
NASA Astrophysics Data System (ADS)
Robledo, L. M.; Bernard, R. N.; Bertsch, G. F.
2014-02-01
The Gallagher-Moszkowski rule in the spectroscopy of odd-odd nuclei imposes a new spin constraint on the energy functionals for self-consistent mean field theory. The commonly used parametrization of the effective three-body interaction in the Gogny and Skyrme families of energy functionals is ill suited to satisfy the spin constraint. In particular, the Gogny parametrization of the three-body interaction has the spin dependence opposite to that required by the observed spectra. The two-body part has a correct sign, but in combination the rule is violated as often as not. We conclude that a new functional form is needed for the effective three-body interaction that can take into better account the different spin-isospin channels of the interaction.
New Generation Nuclear Plant -- High Level Functions and Requirements
J. M. Ryskamp; E. J. Gorski; E. A. Harvego; S. T. Khericha; G. A. Beitel
2003-09-01
This functions and requirements (F&R) document was prepared for the Next Generation Nuclear Plant (NGNP) Project. The highest-level functions and requirements for the NGNP preconceptual design are identified in this document, which establishes performance definitions for what the NGNP will achieve. NGNP designs will be developed based on these requirements by commercial vendor(s).
US Nuclear Regulatory Commission organization charts and functional statements
1997-11-01
This document contains organization charts for the U.S. Nuclear Regulatory Commission (NRC) and for the five offices of the NRC. Function statements are provided delineating the major responsibilities and operations of each office. Organization and function are provided to the branch level. The head of each office, division, and branch is also listed.
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. PMID:22979846
NASA Astrophysics Data System (ADS)
López-Rosa, S.; Esquivel, R. O.; Plastino, A. R.; Dehesa, J. S.
2015-09-01
In this work we have performed state-of-the-art configuration-interaction (CI) calculations to determine the linear and von Neumann entanglement entropies for the helium-like systems with varying nuclear charge Z in the range 1≤slant Z≤slant 10. The focus of the work resides on determining accurate entanglement values for 2-electron systems with the lowest computational cost through compact CI-wave functions. Our entanglement results for the helium atom fully agree with the results obtained with higher quality wave functions of the Kinoshita type (Dehesa [5]). We find that the correlation energy is linearly related to the entanglement measures associated with the linear and von Neumann entropies of the single-particle reduced density matrizes, which sheds new light on the physical implications of entanglement in helium-like systems. Moreover, we report CI-wave-function-based benchmark results for the entanglement values for all members of the helium isoelectronic series with an accuracy similar to that of Kinoshita-type wave functions. Finally, we give parametric expressions of the linear and von Neumann entanglement measures for two-electron systems as Z varies from 1 to 10.
Exact density functional and wave function embedding schemes based on orbital localization
NASA Astrophysics Data System (ADS)
Hégely, Bence; Nagy, Péter R.; Ferenczy, György G.; Kállay, Mihály
2016-08-01
Exact schemes for the embedding of density functional theory (DFT) and wave function theory (WFT) methods into lower-level DFT or WFT approaches are introduced utilizing orbital localization. First, a simple modification of the projector-based embedding scheme of Manby and co-workers [J. Chem. Phys. 140, 18A507 (2014)] is proposed. We also use localized orbitals to partition the system, but instead of augmenting the Fock operator with a somewhat arbitrary level-shift projector we solve the Huzinaga-equation, which strictly enforces the Pauli exclusion principle. Second, the embedding of WFT methods in local correlation approaches is studied. Since the latter methods split up the system into local domains, very simple embedding theories can be defined if the domains of the active subsystem and the environment are treated at a different level. The considered embedding schemes are benchmarked for reaction energies and compared to quantum mechanics (QM)/molecular mechanics (MM) and vacuum embedding. We conclude that for DFT-in-DFT embedding, the Huzinaga-equation-based scheme is more efficient than the other approaches, but QM/MM or even simple vacuum embedding is still competitive in particular cases. Concerning the embedding of wave function methods, the clear winner is the embedding of WFT into low-level local correlation approaches, and WFT-in-DFT embedding can only be more advantageous if a non-hybrid density functional is employed.
Inside looking out: Probing JIMWLK wave functions with BFKL calculations
Altinoluk, Tolga; Kovner, Alex; Levin, Eugene
2010-10-01
We investigate the relation between the eigenvalues and eigenfunctions of the Balitsky-Fadin-Kuraev-Lipatov (BFKL) and Jalilian-Marian-Iancu-McLerran-Weigert-Leonidov-Kovner (JIMWLK/KLWMIJ) Hamiltonians. We show that the eigenvalues of the BFKL Hamiltonians are also exact eigenvalues of the KLWMIJ (and JIMWLK) Hamiltonian, albeit corresponding to possibly non-normalizable eigenfunctions. The question whether a given eigenfunction of BFKL corresponds to a normalizable eigenfunction of KLWMIJ is rather complicated, except in some obvious cases, and requires independent investigation. As an example to illustrate this relation we concentrate on the color octet exchange in the framework of KLWMIJ Hamiltonian. We show that it corresponds to the reggeized gluon exchange of BFKL, and find first correction to the BFKL wave function, which has the meaning of the impact factor for shadowing correction to the Reggeized gluon. We also show that the bootstrap condition in the KLWMIJ framework is satisfied automatically and does not carry any additional information to that contained in the second quantized structure of the KLWMIJ Hamiltonian. This is an example of how the bootstrap condition inherent in the t-channel unitarity arises in the s-channel picture.
Newton force from wave function collapse: speculation and test
NASA Astrophysics Data System (ADS)
Diósi, Lajos
2014-04-01
The Diosi-Penrose model of quantum-classical boundary postulates gravity-related spontaneous wave function collapse of massive degrees of freedom. The decoherence effects of the collapses are in principle detectable if not masked by the overwhelming environmental decoherence. But the DP (or any other, like GRW, CSL) spontaneous collapses are not detectable themselves, they are merely the redundant formalism of spontaneous decoherence. To let DP collapses become testable physics, recently we extended the DP model and proposed that DP collapses are responsible for the emergence of the Newton gravitational force between massive objects. We identified the collapse rate, possibly of the order of 1/ms, with the rate of emergence of the Newton force. A simple heuristic emergence (delay) time was added to the Newton law of gravity. This non-relativistic delay is in peaceful coexistence with Einstein's relativistic theory of gravitation, at least no experimental evidence has so far surfaced against it. We derive new predictions of such a 'lazy' Newton law that will enable decisive laboratory tests with available technologies. The simple equation of 'lazy' Newton law deserves theoretical and experimental studies in itself, independently of the underlying quantum foundational considerations.
Covariant nucleon wave function with S, D, and P-state components
Franz Gross, G. Ramalho, M. T. Pena
2012-05-01
Expressions for the nucleon wave functions in the covariant spectator theory (CST) are derived. The nucleon is described as a system with a off-mass-shell constituent quark, free to interact with an external probe, and two spectator constituent quarks on their mass shell. Integrating over the internal momentum of the on-mass-shell quark pair allows us to derive an effective nucleon wave function that can be written only in terms of the quark and diquark (quark-pair) variables. The derived nucleon wave function includes contributions from S, P and D-waves.
Hairless is a nuclear receptor corepressor essential for skin function
Thompson, Catherine C.
2009-01-01
The activity of nuclear receptors is modulated by numerous coregulatory factors. Corepressors can either mediate the ability of nuclear receptors to repress transcription, or can inhibit transactivation by nuclear receptors. As we learn more about the mechanisms of transcriptional repression, the importance of repression by nuclear receptors in development and disease has become clear. The protein encoded by the mammalian Hairless (Hr) gene was shown to be a corepressor by virtue of its functional similarity to the well-established corepressors N-CoR and SMRT. Mutation of the Hr gene results in congenital hair loss in both mice and men. Investigation of Hairless function both in vitro and in mouse models in vivo has revealed a critical role in maintaining skin and hair by regulating the differentiation of epithelial stem cells, as well as a putative role in regulating gene expression via chromatin remodeling. PMID:20087431
Attosecond photoemission dynamics encoded in real-valued continuum wave functions
NASA Astrophysics Data System (ADS)
Gaillac, Romain; Vacher, Morgane; Maquet, Alfred; Taïeb, Richard; Caillat, Jérémie
2016-01-01
The dynamics of photoemission is fully encoded in the continuum wave functions selected by the transitions. Using numerical simulations on simple benchmark models, we show how scattering phase shifts and photoemission delays can be retrieved from this unambiguously defined class of wave functions. In contrast with standard scattering waves inherited from collision theory, they are real-valued for one-photon transitions and provide a clear-cut interpretation of the delays recently discussed in the framework of attosecond science.
NASA Astrophysics Data System (ADS)
Múnera, Héctor A.
2016-07-01
It is postulated that there exists a fundamental energy-like fluid, which occupies the flat three-dimensional Euclidean space that contains our universe, and obeys the two basic laws of classical physics: conservation of linear momentum, and conservation of total energy; the fluid is described by the classical wave equation (CWE), which was Schrödinger's first candidate to develop his quantum theory. Novel solutions for the CWE discovered twenty years ago are nonharmonic, inherently quantized, and universal in the sense of scale invariance, thus leading to quantization at all scales of the universe, from galactic clusters to the sub-quark world, and yielding a unified Lorentz-invariant quantum theory ab initio. Quingal solutions are isomorphic under both neo-Galilean and Lorentz transformations, and exhibit nother remarkable property: intrinsic unstability for large values of ℓ (a quantum number), thus limiting the size of each system at a given scale. Unstability and scale-invariance together lead to nested structures observed in our solar system; unstability may explain the small number of rows in the chemical periodic table, and nuclear unstability of nuclides beyond lead and bismuth. Quingal functions lend mathematical basis for Boscovich's unified force (which is compatible with many pieces of evidence collected over the past century), and also yield a simple geometrical solution for the classical three-body problem, which is a useful model for electronic orbits in simple diatomic molecules. A testable prediction for the helicoidal-type force is suggested.
Irregular wave functions of a hydrogen atom in a uniform magnetic field
Wintgen, D. Max-Planck-Institut fuer Kernphysik, Postfach 103980, D-6900 Heidelberg, ); Honig, A. )
1989-10-02
We study the irregular wave functions of a highly excited hydrogen atom in a uniform magnetic field. The scarring of wave functions by periodic orbits is quantitatively investigated. The shape of unperturbed scars is in good agreement with recent semiclassical predictions.
Nuclear correlation functions in lattice QCD
Detmold, William; Orginos, Konstantinos
2013-06-01
We consider the problem of calculating the large number of Wick contractions necessary to compute states with the quantum numbers of many baryons in lattice QCD. We consider a constructive approach and a determinant-based approach and show that these methods allow the required contractions to be performed for certain choices of interpolating operators. Examples of correlation functions computed using these techniques are shown for the quantum numbers of the light nuclei, $^4$He, $^8$Be, $^{12}$C, $^{16}$O and $^{28}$Si.
Nuclear cardiology: Myocardial perfusion and function
Seldin, D.W. )
1991-08-01
Myocardial perfusion studies continue to be a major focus of research, with new investigations of the relationship of exercise-redistribution thallium imaging to diagnosis, prognosis, and case management. The redistribution phenomenon, which seemed to be fairly well understood a few years ago, is now recognized to be much more complex than originally thought, and various strategies have been proposed to clarify the meaning of persistent defects. Pharmacologic intervention with dipyridamole and adenosine has become available as an alternative to exercise, and comparisons with exercise imaging and catheterization results have been described. Thallium itself is no longer the sole single-photon perfusion radiopharmaceutical; two new technetium agents are now widely available. In addition to perfusion studies, advances in the study of ventricular function have been made, including reports of studies performed in conjunction with technetium perfusion studies, new insights into cardiac physiology, and the prognostic and case-management information that function studies provide. Finally, work has continued with monoclonal antibodies for the identification of areas of myocyte necrosis. 41 references.
A-dependence of weak nuclear structure functions
Haider, H.; Athar, M. Sajjad; Simo, I. Ruiz
2015-05-15
Effect of nuclear medium on the weak structure functions F{sub 2}{sup A}(x, Q{sup 2}) and F{sub 3}{sup A}(x, Q{sup 2}) have been studied using charged current (anti)neutrino deep inelastic scattering on various nuclear targets. Relativistic nuclear spectral function which incorporate Fermi motion, binding and nucleon correlations are used for the calculations. We also consider the pion and rho meson cloud contributions calculated from a microscopic model for meson-nucleus self-energies. Using these structure functions, F{sub i}{sup A}/F{sub i}{sup proton} and F{sub i}{sup A}/F{sub i}{sup deuteron}(i=2,3, A={sup 12}C, {sup 16}O, CH and H{sub 2}O) are obtained.
Efficient and Flexible Computation of Many-Electron Wave Function Overlaps
2016-01-01
A new algorithm for the computation of the overlap between many-electron wave functions is described. This algorithm allows for the extensive use of recurring intermediates and thus provides high computational efficiency. Because of the general formalism employed, overlaps can be computed for varying wave function types, molecular orbitals, basis sets, and molecular geometries. This paves the way for efficiently computing nonadiabatic interaction terms for dynamics simulations. In addition, other application areas can be envisaged, such as the comparison of wave functions constructed at different levels of theory. Aside from explaining the algorithm and evaluating the performance, a detailed analysis of the numerical stability of wave function overlaps is carried out, and strategies for overcoming potential severe pitfalls due to displaced atoms and truncated wave functions are presented. PMID:26854874
Fractal dimensions of wave functions and local spectral measures on the Fibonacci chain
NASA Astrophysics Data System (ADS)
Macé, Nicolas; Jagannathan, Anuradha; Piéchon, Frédéric
2016-05-01
We present a theoretical framework for understanding the wave functions and spectrum of an extensively studied paradigm for quasiperiodic systems, namely the Fibonacci chain. Our analytical results, which are obtained in the limit of strong modulation of the hopping amplitudes, are in good agreement with published numerical data. In the perturbative limit, we show a symmetry of wave functions under permutation of site and energy indices. We compute the wave-function renormalization factors and from them deduce analytical expressions for the fractal exponents corresponding to individual wave functions, as well as their global averages. The multifractality of wave functions is seen to appear at next-to-leading order in ρ . Exponents for the local spectral density are given, in extremely good accord with numerical calculations. Interestingly, our analytical results for exponents are observed to describe the system rather well even for values of ρ well outside the domain of applicability of perturbation theory.
Argonov, V. Yu.
2014-11-15
The wave function of a moderately cold atom in a stationary near-resonant standing light wave delocalizes very fast due to wave packet splitting. However, we show that frequency modulation of the field can suppress packet splitting for some atoms whose specific velocities are in a narrow range. These atoms remain localized in a small space for a long time. We demonstrate and explain this effect numerically and analytically. We also demonstrate that the modulated field can not only trap but also cool the atoms. We perform a numerical experiment with a large atomic ensemble having wide initial velocity and energy distributions. During the experiment, most of atoms leave the wave while the trapped atoms have a narrow energy distribution.
Submillimeter-Wave Spectroscopic Instruments: Multi-functional Atmospheric Characterization
NASA Astrophysics Data System (ADS)
Mehdi, I.; Gulkis, S.; Allen, M. A.; Schlecht, E.; Chattopadhyay, G.
2012-10-01
Submillimeter-wave spectroscopic instruments provide unique capability in terms of providing quantitative measurements of trace gas compositions in planetary atmospheres. Such instruments also provide temporal and wind velocity mapping capability.
NASA Astrophysics Data System (ADS)
Bernardino, M. J.; Jones, C. H.
2013-12-01
Past seismic studies attempting to image the lithosphere underneath the Sierra Nevada and to constrain the geometry of the upper mantle Isabella anomaly, a high wave-speed body underneath the western foothills of the range, have observed complex behavior in teleseismic and regional waveforms recorded at stations within the range. Notably, a 1993 teleseismic mini-array recorded multipath P-wave arrivals, topographic reflections, and scattered energy ~25 km west of the Sierran crest. These effects suggest wave propagation through strongly heterogeneous lithosphere complicated by near-surface phenomena. Multipathing and other complex wave propagation are indicative of strong variations in wavespeed, which in turn reflect structural complexity important in understanding the genesis of the Isabella anomaly. However, determining the extent of such propagative behavior in and underneath the Sierra Nevada has not been studied. We investigate the behavior of teleseismic P-waves using vertical-component receiver functions in an effort to better understand the extent of complex waveforms as a first tool in better constraining the geographic region(s) where sufficiently complex lithospheric structure exists. We expect that the presence of sufficiently high velocity gradients should result in P-wave multipath arrivals from events that skirt the perimeter of the Isabella anomaly from certain backazimuths. We deconvolve regionally beamed vertical P-waveforms from individual vertical component P-waves. This effectively recovers variability in the P waveforms that is normally lost in typical single-station radial- and transverse-component receiver function analyses. Vertical P-wave beams are constructed using dbxcor, a waveform correlation algorithm developed by G. Pavlis. Seismic data for the northern and central Sierra Nevada are from the 2005-2007 Sierra Nevada Earthscope Project (SNEP) and further supplemented by many permanent and temporary stations including the Earthscope
Thermoelastic Stress in a Functionally Graded Infinite Plate with Electromagnetic Wave Absorption
NASA Astrophysics Data System (ADS)
Tian, Hong-Yan; Wang, Xing-Zhe; Zhou, You-He
2012-11-01
We present an analysis of thermal and thermoelastic behaviors of a functionally graded infinite plate taking into account electromagnetic wave absorption. To treat with the inhomogeneity of functionally graded wave-absorbing (FGWA) materials, the plate is approximated by subdividing it into thin homogeneous layers to solve the governing equations together with proper boundary and connecting conditions. The results illustrate that the FGWA plate is a broadband type absorber with electromagnetic wave absorption. By choosing proper material gradation character and the thickness of the FGWA plate, it is possible to obtain a good performance of electromagnetic wave absorption and thermoelastic stress characteristics.
Numerical methods for the calculation of special functions of wave catastrophes
NASA Astrophysics Data System (ADS)
Ipatov, E. B.; Lukin, D. S.; Palkin, E. A.
1985-02-01
The paper investigates the properties of special functions which are used for the asymptotic description of the structure of wave fields near various types of focusings. These functions are realized in software packages for the BESM-6 computer using FORTRAN. The canonical equations and basic properties of these functions are examined along with the development of numerical algorithms for their computation. These functions may be applied in the study of various types of wave problems, including: (1) radio wave propagation in the ionosphere and ionospheric waveguide channels; (2) the fine structure of sound fields in an acoustic duct; and (3) the focusing of laser radiation reflected from a rough surface.
NASA Astrophysics Data System (ADS)
Gross, Franz; Stadler, Alfred
2010-09-01
We present the effective range expansions for the 1S0 and 3S1 scattering phase shifts, and the relativistic deuteron wave functions that accompany our recent high precision fits (with χ2/Ndata≃1) to the 2007 world np data below 350 MeV. The wave functions are expanded in a series of analytical functions (with the correct asymptotic behavior at both large and small arguments) that can be Fourier-transformed from momentum to coordinate space and are convenient to use in any application. A fortran subroutine to compute these wave functions can be obtained from the authors.
Franz Gross, Alfred Stadler
2010-09-01
We present the effective range expansions for the 1S0 and 3S1 scattering phase shifts, and the relativistic deuteron wave functions that accompany our recent high precision fits (with \\chi^2/N{data} \\simeq 1) to the 2007 world np data below 350 MeV. The wave functions are expanded in a series of analytical functions (with the correct asymptotic behavior at both large and small arguments) that can be Fourier-transformed from momentum to coordinate space and are convenient to use in any application. A fortran subroutine to compute these wave functions can be obtained from the authors.
Rezende, Carlos A; San Gil, Rosane A S; Borré, Leandro B; Pires, José Ricardo; Vaiss, Viviane S; Resende, Jackson A L C; Leitão, Alexandre A; De Alencastro, Ricardo B; Leal, Katia Z
2016-09-01
The experiments of carvedilol form II, form III, and hydrate by (13)C and (15)N cross-polarization magic-angle spinning (CP MAS) are reported. The GIPAW (gauge-including projector-augmented wave) method from DFT (density functional theory) calculations was used to simulate (13)C and (15)N chemical shifts. A very good agreement was found for the comparison between the global results of experimental and calculated nuclear magnetic resonance (NMR) chemical shifts for carvedilol polymorphs. This work aims a comprehensive understanding of carvedilol crystalline forms employing solution and solid-state NMR as well as DFT calculations. PMID:26372719
Quantum-defect functions. Interconverters of electronic and nuclear motion
Dill, D.; Jungen, C.
1980-08-21
In 1964 Mulliken systematically extended the ideas of Rydberg states and quantum defects from atoms to molecules. The key point of that extension is stated in several sentences: In molecules...all that has just been stated for atomic Rydberg states finds a parallel if one considers any one fixed nuclear configuration... However the mode of variation of the MOs and their energies as one varies the nuclear configuration is a new feature of interest. A complication...is the fact that the interaction of the molecular rotation with the l vector of the Rydberg electron changes radically as n increases in a Rydberg series. Thereby Mulliken introduced the concept of the quantum-defect function, ..mu lambda..(R), depending on nuclear configuration R and orbital-momentum projection ..lambda.. along the molecular axis. This concept has emerged as central to the understanding of the interconversion of electronic and nuclear motion in molecular systems. 13 figures.
Probability function of breaking-limited surface elevation. [wind generated waves of ocean
NASA Technical Reports Server (NTRS)
Tung, C. C.; Huang, N. E.; Yuan, Y.; Long, S. R.
1989-01-01
The effect of wave breaking on the probability function of surface elevation is examined. The surface elevation limited by wave breaking zeta sub b(t) is first related to the original wave elevation zeta(t) and its second derivative. An approximate, second-order, nonlinear, non-Gaussian model for zeta(t) of arbitrary but moderate bandwidth is presented, and an expression for the probability density function zeta sub b(t) is derived. The results show clearly that the effect of wave breaking on the probability density function of surface elevation is to introduce a secondary hump on the positive side of the probability density function, a phenomenon also observed in wind wave tank experiments.
Public meetings on nuclear waste management: their function and organization
Duvernoy, E.G.; Marcus, A.A.; Overcast, T.; Schilling, A.H.
1981-05-01
This report focuses on public meetings as a vehicle for public participation in nuclear waste management. The nature of public meetings is reviewed and the functions served by meetings highlighted. The range of participants and their concerns are addressed, including a review of the participants from past nuclear waste management meetings. A sound understanding of the expected participants allows DOE to tailor elements of the meeting, such as notification, format, and agenda to accommodate the attendees. Finally, the report discusses the organization of public meetings on nuclear waste management in order to enhance the DOE's functions for such meetings. Possible structures are suggested for a variety of elements that are relevant prior to, during and after the public meeting. These suggestions are intended to supplement the DOE Public Participation Manual.
Uncertainty Quantification and Propagation in Nuclear Density Functional Theory
Schunck, N; McDonnell, J D; Higdon, D; Sarich, J; Wild, S M
2015-03-17
Nuclear density functional theory (DFT) is one of the main theoretical tools used to study the properties of heavy and superheavy elements, or to describe the structure of nuclei far from stability. While on-going eff orts seek to better root nuclear DFT in the theory of nuclear forces, energy functionals remain semi-phenomenological constructions that depend on a set of parameters adjusted to experimental data in fi nite nuclei. In this paper, we review recent eff orts to quantify the related uncertainties, and propagate them to model predictions. In particular, we cover the topics of parameter estimation for inverse problems, statistical analysis of model uncertainties and Bayesian inference methods. Illustrative examples are taken from the literature.
BUILDING A UNIVERSAL NUCLEAR ENERGY DENSITY FUNCTIONAL (UNEDF)
Nazarewicz, Witold
2012-07-01
The long-term vision initiated with UNEDF is to arrive at a comprehensive, quantitative, and unified description of nuclei and their reactions, grounded in the fundamental interactions between the constituent nucleons. We seek to replace current phenomenological models of nuclear structure and reactions with a well-founded microscopic theory that delivers maximum predictive power with well-quantified uncertainties. Specifically, the mission of this project has been three-fold: First, to find an optimal energy density functional (EDF) using all our knowledge of the nucleonic Hamiltonian and basic nuclear properties. Second, to apply the EDF theory and its extensions to validate the functional using all the available relevant nuclear structure and reaction data. Third, to apply the validated theory to properties of interest that cannot be measured, in particular the properties needed for reaction theory.
NASA Astrophysics Data System (ADS)
Zhao, Lian-Feng; Xie, Xiao-Bi; Tian, Bao-Feng; Chen, Qi-Fu; Hao, Tian-Yao; Yao, Zhen-Xing
2015-11-01
We investigate the geometric spreading and attenuation of seismic Pn waves in Northeast China and the Korean Peninsula. A high-quality broadband Pn wave data set generated by North Korean nuclear tests is used to constrain the parameters of a frequency-dependent log-quadratic geometric spreading function and a power law Pn Q model. The geometric spreading function and apparent Pn wave Q are obtained for Northeast China and the Korean Peninsula between 2.0 and 10.0 Hz. Using the two-station amplitude ratios of the Pn spectra and correcting them with the known spreading function, we remove the contributions of the source and crust from the apparent Pn Q and retrieve the P wave attenuation information along the pure upper mantle path. We then use both Pn amplitudes and amplitude ratios in a tomographic approach to obtain the upper mantle P wave attenuation in the studied area. The Pn wave spectra observed in China are compared with those recorded in Japan, and the result reveals that the high-frequency Pn signal across the oceanic path attenuated faster compared with those through the continental path.
Reflection-Asymmetric Nuclear Deformations within the Density Functional Theory
Olsen, E; Erler, J; Nazarewicz, W.; Stoitsov, M
2012-01-01
Within the nuclear density functional theory (DFT) we study the effect of reflection- asymmetric shapes on ground-state binding energies and binding energy differences. To this end, we developed the new DFT solver axialhfb that uses an approximate second-order gradient to solve the Hartree-Fock-Bogoliubov equations of superconducting DFT with the quasi-local Skyrme energy density functionals. Illustrative calculations are carried out for even- even isotopes of radium and thorium.
Nanotopographical Modulation of Cell Function through Nuclear Deformation
Wang, Kai; Bruce, Allison; Mezan, Ryan; Kadiyala, Anand; Wang, Liying; Dawson, Jeremy; Rojanasakul, Yon; Yang, Yong
2016-01-01
Although nanotopography has been shown to be a potent modulator of cell behavior, it is unclear how the nanotopographical cue, through focal adhesions, affects the nucleus, eventually influencing cell phenotype and function. Thus, current methods to apply nanotopography to regulate cell behavior are basically empirical. We, herein, engineered nanotopographies of various shapes (gratings and pillars) and dimensions (feature size, spacing and height), and thoroughly investigated cell spreading, focal adhesion organization and nuclear deformation of human primary fibroblasts as the model cell grown on the nanotopographies. We examined the correlation between nuclear deformation and cell functions such as cell proliferation, transfection and extracellular matrix protein type I collagen production. It was found that the nanoscale gratings and pillars could facilitate focal adhesion elongation by providing anchoring sites, and the nanogratings could orient focal adhesions and nuclei along the nanograting direction, depending on not only the feature size but also the spacing of the nanogratings. Compared with continuous nanogratings, discrete nanopillars tended to disrupt the formation and growth of focal adhesions and thus had less profound effects on nuclear deformation. Notably, nuclear volume could be effectively modulated by the height of nanotopography. Further, we demonstrated that cell proliferation, transfection, and type I collagen production were strongly associated with the nuclear volume, indicating that the nucleus serves as a critical mechanosensor for cell regulation. Our study delineated the relationships between focal adhesions, nucleus and cell function and highlighted that the nanotopography could regulate cell phenotype and function by modulating nuclear deformation. This study provides insight into the rational design of nanotopography for new biomaterials and the cell–substrate interfaces of implants and medical devices. PMID:26844365
Goal Direction and Effectiveness, Emotional Maturity, and Nuclear Family Functioning
ERIC Educational Resources Information Center
Klever, Phillip
2009-01-01
Differentiation of self, a cornerstone concept in Bowen theory, has a profound influence over time on the functioning of the individual and his or her family unit. This 5-year longitudinal study tested this hypothesis with 50 developing nuclear families. The dimensions of differentiation of self that were examined were goal direction and…
Comparison of quasi-Hartree-Fock wave-functions for lithium hydride
NASA Astrophysics Data System (ADS)
Asthalter, T.; Weyrich, W.; Harker, A. H.; Kunz, A. B.; Orlando, R.; Pisani, C.
1992-09-01
We compare the Hartree-Fock wave-functions for crystalline LiH obtained either with a standard Crystalline-Orbital—LCAO procedure or following the Adams-Gilbert-Kunz (AGK) prescription. Total energy, band-structure, reciprocal form factors [ B( r)] are taken as a reference, for checking the quality of the wave-function. The influence of the inclusion of high angular-quantum-number functions in the AGK basis set is explored.
Longitudinal wave function control in single quantum dots with an applied magnetic field
Cao, Shuo; Tang, Jing; Gao, Yunan; Sun, Yue; Qiu, Kangsheng; Zhao, Yanhui; He, Min; Shi, Jin-An; Gu, Lin; Williams, David A.; Sheng, Weidong; Jin, Kuijuan; Xu, Xiulai
2015-01-01
Controlling single-particle wave functions in single semiconductor quantum dots is in demand to implement solid-state quantum information processing and spintronics. Normally, particle wave functions can be tuned transversely by an perpendicular magnetic field. We report a longitudinal wave function control in single quantum dots with a magnetic field. For a pure InAs quantum dot with a shape of pyramid or truncated pyramid, the hole wave function always occupies the base because of the less confinement at base, which induces a permanent dipole oriented from base to apex. With applying magnetic field along the base-apex direction, the hole wave function shrinks in the base plane. Because of the linear changing of the confinement for hole wave function from base to apex, the center of effective mass moves up during shrinking process. Due to the uniform confine potential for electrons, the center of effective mass of electrons does not move much, which results in a permanent dipole moment change and an inverted electron-hole alignment along the magnetic field direction. Manipulating the wave function longitudinally not only provides an alternative way to control the charge distribution with magnetic field but also a new method to tune electron-hole interaction in single quantum dots. PMID:25624018
Coherent molecular transistor: Control through variation of the gate wave function
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.
Wave Distribution Functions of Plasmaspheric Hiss and their Effects on Radiation Belt Dynamics
NASA Astrophysics Data System (ADS)
Santolik, O.; Ripoll, J. F.; Kurth, W. S.; Hospodarsky, G. B.; Kletzing, C.
2015-12-01
Plasmaspheric hiss is formed by whistler-mode waves which play an important role in the dynamics the Earth's radiation belts, specifically in connection with the slot region between the inner and outer Van Allen belts. The origin of plasmaspheric hiss is still a subject of discussions and these waves are known for their complex propagation properties. They are often far from a single plane wave approximation, forming a continuous distribution of the wave energy density with respect to the wave vector direction (wave distribution function). Analysis of polarization and propagation parameters of these waves provides us with inputs for modeling of radiation belt dynamics. We use the data of the Waves instrument of Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) onboard the Van Allen Probes spacecraft, to analyze simultaneous measurements of all electric and magnetic field components, together with measurements of the plasma density based on the determination of the upper hybrid resonance frequency. Using this unique data set we estimate the wave distribution functions of plasmaspheric hiss and we model the effects of these waves on the decay rates of radiation belt electrons through quasilinear pitch angle diffusion.
Protective measurement of the wave function of a single squeezed harmonic-oscillator state
NASA Astrophysics Data System (ADS)
Alter, Orly; Yamamoto, Yoshihisa
1996-05-01
A scheme for the "protective measurement"
NASA Astrophysics Data System (ADS)
Shchadilova, Yulia E.; Grusdt, Fabian; Rubtsov, Alexey N.; Demler, Eugene
2016-04-01
We propose a class of variational Gaussian wave functions to describe Fröhlich polarons at finite momenta. Our wave functions give polaron energies that are in excellent agreement with the existing Monte Carlo results for a broad range of interactions. We calculate the effective mass of polarons and find smooth crossover between weak- and intermediate-coupling strength. Effective masses that we obtain are considerably larger than those predicted by the mean-field method. A prediction based on our variational wave functions is a special pattern of correlations between host atoms that can be measured in time-of-flight experiments.
Degenerate RS perturbation theory. [Rayleigh-Schroedinger energies and wave functions
NASA Technical Reports Server (NTRS)
Hirschfelder, J. O.; Certain, P. R.
1974-01-01
A concise, systematic procedure is given for determining the Rayleigh-Schroedinger energies and wave functions of degenerate states to arbitrarily high orders even when the degeneracies of the various states are resolved in arbitrary orders. The procedure is expressed in terms of an iterative cycle in which the energy through the (2n + 1)-th order is expressed in terms of the partially determined wave function through the n-th order. Both a direct and an operator derivation are given. The two approaches are equivalent and can be transcribed into each other. The direct approach deals with the wave functions (without the use of formal operators) and has the advantage that it resembles the usual treatment of nondegenerate perturbations and maintains close contact with the basic physics. In the operator approach, the wave functions are expressed in terms of infinite-order operators which are determined by the successive resolution of the space of the zeroth-order functions.
Ocean wave-radar modulation transfer functions from the West Coast experiment
NASA Technical Reports Server (NTRS)
Wright, J. W.; Plant, W. J.; Keller, W. C.; Jones, W. L.
1980-01-01
Short gravity-capillary waves, the equilibrium, or the steady state excitations of the ocean surface are modulated by longer ocean waves. These short waves are the predominant microwave scatterers on the ocean surface under many viewing conditions so that the modulation is readily measured with CW Doppler radar used as a two-scale wave probe. Modulation transfer functions (the ratio of the cross spectrum of the line-of-sight orbital speed and backscattered microwave power to the autospectrum of the line-of-sight orbital speed) were measured at 9.375 and 1.5 GHz (Bragg wavelengths of 2.3 and 13 cm) for winds up to 10 m/s and ocean wave periods from 2-18 s. The measurements were compared with the relaxation-time model; the principal result is that a source of modulation other than straining by the horizontal component of orbital speed, possibly the wave-induced airflow, is responsible for most of the modulation by waves of typical ocean wave period (10 s). The modulations are large; for unit coherence, spectra of radar images of deep-water waves should be proportional to the quotient of the slope spectra of the ocean waves by the ocean wave frequency.
Data synthesis and display programs for wave distribution function analysis
NASA Technical Reports Server (NTRS)
Storey, L. R. O.; Yeh, K. J.
1992-01-01
At the National Space Science Data Center (NSSDC) software was written to synthesize and display artificial data for use in developing the methodology of wave distribution analysis. The software comprises two separate interactive programs, one for data synthesis and the other for data display.
McKechnie, Scott; Booth, George H.; Cohen, Aron J.; Cole, Jacqueline M.
2015-05-21
The best practice in computational methods for determining vertical ionization energies (VIEs) is assessed, via reference to experimentally determined VIEs that are corroborated by highly accurate coupled-cluster calculations. These reference values are used to benchmark the performance of density functional theory (DFT) and wave function methods: Hartree-Fock theory, second-order Møller-Plesset perturbation theory, and Electron Propagator Theory (EPT). The core test set consists of 147 small molecules. An extended set of six larger molecules, from benzene to hexacene, is also considered to investigate the dependence of the results on molecule size. The closest agreement with experiment is found for ionization energies obtained from total energy difference calculations. In particular, DFT calculations using exchange-correlation functionals with either a large amount of exact exchange or long-range correction perform best. The results from these functionals are also the least sensitive to an increase in molecule size. In general, ionization energies calculated directly from the orbital energies of the neutral species are less accurate and more sensitive to an increase in molecule size. For the single-calculation approach, the EPT calculations are in closest agreement for both sets of molecules. For the orbital energies from DFT functionals, only those with long-range correction give quantitative agreement with dramatic failing for all other functionals considered. The results offer a practical hierarchy of approximations for the calculation of vertical ionization energies. In addition, the experimental and computational reference values can be used as a standardized set of benchmarks, against which other approximate methods can be compared.
McKechnie, Scott; Booth, George H; Cohen, Aron J; Cole, Jacqueline M
2015-05-21
The best practice in computational methods for determining vertical ionization energies (VIEs) is assessed, via reference to experimentally determined VIEs that are corroborated by highly accurate coupled-cluster calculations. These reference values are used to benchmark the performance of density functional theory (DFT) and wave function methods: Hartree-Fock theory, second-order Møller-Plesset perturbation theory, and Electron Propagator Theory (EPT). The core test set consists of 147 small molecules. An extended set of six larger molecules, from benzene to hexacene, is also considered to investigate the dependence of the results on molecule size. The closest agreement with experiment is found for ionization energies obtained from total energy difference calculations. In particular, DFT calculations using exchange-correlation functionals with either a large amount of exact exchange or long-range correction perform best. The results from these functionals are also the least sensitive to an increase in molecule size. In general, ionization energies calculated directly from the orbital energies of the neutral species are less accurate and more sensitive to an increase in molecule size. For the single-calculation approach, the EPT calculations are in closest agreement for both sets of molecules. For the orbital energies from DFT functionals, only those with long-range correction give quantitative agreement with dramatic failing for all other functionals considered. The results offer a practical hierarchy of approximations for the calculation of vertical ionization energies. In addition, the experimental and computational reference values can be used as a standardized set of benchmarks, against which other approximate methods can be compared. PMID:26001454
Nuclear Functions of Nucleolin through Global Proteomics and Interactomic Approaches.
Salvetti, Anna; Couté, Yohann; Epstein, Alberto; Arata, Loredana; Kraut, Alexandra; Navratil, Vincent; Bouvet, Philippe; Greco, Anna
2016-05-01
Nucleolin (NCL) is a major component of the cell nucleolus, which has the ability to rapidly shuttle to several other cells' compartments. NCL plays important roles in a variety of essential functions, among which are ribosome biogenesis, gene expression, and cell growth. However, the precise mechanisms underlying NCL functions are still unclear. Our study aimed to provide new information on NCL functions via the identification of its nuclear interacting partners. Using an interactomics approach, we identified 140 proteins co-purified with NCL, among which 100 of them were specifically found to be associated with NCL after RNase digestion. The functional classification of these proteins confirmed the prominent role of NCL in ribosome biogenesis and additionally revealed the possible involvement of nuclear NCL in several pre-mRNA processing pathways through its interaction with RNA helicases and proteins participating in pre-mRNA splicing, transport, or stability. NCL knockdown experiments revealed that NCL regulates the localization of EXOSC10 and the amount of ZC3HAV1, two components of the RNA exosome, further suggesting its involvement in the control of mRNA stability. Altogether, this study describes the first nuclear interactome of human NCL and provides the basis for further understanding the mechanisms underlying the essential functions of this nucleolar protein. PMID:27049334
Nuclear cyclophilins affect spliceosome assembly and function in vitro
Adams, B.M.; Coates, Miranda N.; Jackson, S. RaElle; Jurica, Melissa S.; Davis, Tara L.
2015-01-01
Cyclophilins are ubiquitously expressed proteins that bind to prolines and can catalyse cis/trans isomerization of proline residues. There are 17 annotated members of the cyclophilin family in humans, ubiquitously expressed and localized variously to the cytoplasm, nucleus or mitochondria. Surprisingly, all eight of the nuclear localized cyclophilins are found associated with spliceosomal complexes. However, their particular functions within this context are unknown. We have therefore adapted three established assays for in vitro pre-mRNA splicing to probe the functional roles of nuclear cyclophilins in the context of the human spliceosome. We find that four of the eight spliceosom-associated cyclophilins exert strong effects on splicing in vitro. These effects are dose-dependent and, remarkably, uniquely characteristic of each cyclophilin. Using both qualitative and quantitative means, we show that at least half of the nuclear cyclophilins can act as regulatory factors of spliceosome function in vitro. The present work provides the first quantifiable evidence that nuclear cyclophilins are splicing factors and provides a novel approach for future work into small molecule-based modulation of pre-mRNA splicing. PMID:25967372
Building A Universal Nuclear Energy Density Functional (UNEDF)
Joe Carlson; Dick Furnstahl; Mihai Horoi; Rusty Lusk; Witek Nazarewicz; Esmond Ng; Ian Thompson; James Vary
2012-09-30
During the period of Dec. 1 2006 - Jun. 30, 2012, the UNEDF collaboration carried out a comprehensive study of all nuclei, based on the most accurate knowledge of the strong nuclear interaction, the most reliable theoretical approaches, the most advanced algorithms, and extensive computational resources, with a view towards scaling to the petaflop platforms and beyond. The long-term vision initiated with UNEDF is to arrive at a comprehensive, quantitative, and unified description of nuclei and their reactions, grounded in the fundamental interactions between the constituent nucleons. We seek to replace current phenomenological models of nuclear structure and reactions with a well-founded microscopic theory that delivers maximum predictive power with well-quantified uncertainties. Specifically, the mission of this project has been three-fold: first, to find an optimal energy density functional (EDF) using all our knowledge of the nucleonic Hamiltonian and basic nuclear properties; second, to apply the EDF theory and its extensions to validate the functional using all the available relevant nuclear structure and reaction data; third, to apply the validated theory to properties of interest that cannot be measured, in particular the properties needed for reaction theory. The main physics areas of UNEDF, defined at the beginning of the project, were: ab initio structure; ab initio functionals; DFT applications; DFT extensions; reactions.
NASA Astrophysics Data System (ADS)
Yang, S. Y.; Liu, X.; Cao, D. F.; Mei, H.; Lei, Z. T.; Liu, L. S.
2013-03-01
The development of Functionally Graded Materials (FGM) for energy-absorbing applications requires understanding of stress wave propagation in these structures in order to optimize their resistance to failure. One-dimensional stress wave in FGM composites under elastic and plastic wave loading have been investigated. The stress distributions through the thickness and stress status have been analyzed and some comparisons have been done with the materials of sharp interfaces (two-layered material). The results demonstrate that the gradient structure design greatly decreases the severity of the stress concentrations at the interfaces and there are no clear differences in stress distribution in FGM composites under elastic and plastic wave loading.
Dipole polarizability of 120Sn and nuclear energy density functionals
NASA Astrophysics Data System (ADS)
Hashimoto, T.; Krumbholz, A. M.; Reinhard, P.-G.; Tamii, A.; von Neumann-Cosel, P.; Adachi, T.; Aoi, N.; Bertulani, C. A.; Fujita, H.; Fujita, Y.; GanioÇ§lu, E.; Hatanaka, K.; Ideguchi, E.; Iwamoto, C.; Kawabata, T.; Khai, N. T.; Krugmann, A.; Martin, D.; Matsubara, H.; Miki, K.; Neveling, R.; Okamura, H.; Ong, H. J.; Poltoratska, I.; Ponomarev, V. Yu.; Richter, A.; Sakaguchi, H.; Shimbara, Y.; Shimizu, Y.; Simonis, J.; Smit, F. D.; Süsoy, G.; Suzuki, T.; Thies, J. H.; Yosoi, M.; Zenihiro, J.
2015-09-01
The electric dipole strength distribution in 120Sn between 5 and 22 MeV has been determined at the Research Center for Nuclear Physics, Osaka, from polarization transfer observables measured in proton inelastic scattering at E0=295 MeV and forward angles including 0∘. Combined with photoabsorption data, a highly precise electric dipole polarizability αD(120Sn) =8.93 (36 ) fm3 is extracted. The dipole polarizability as isovector observable par excellence carries direct information on nuclear symmetry energy and its density dependence. The correlation of the new value with the well-established αD(208Pb) serves as a test of its prediction by nuclear energy density functionals. Models based on modern Skyrme interactions describe the data fairly well while most calculations based on relativistic Hamiltonians cannot.
NASA Astrophysics Data System (ADS)
Ramezanpour, A.
2016-06-01
We study the inverse problem of constructing an appropriate Hamiltonian from a physically reasonable set of orthogonal wave functions for a quantum spin system. Usually, we are given a local Hamiltonian and our goal is to characterize the relevant wave functions and energies (the spectrum) of the system. Here, we take the opposite approach; starting from a reasonable collection of orthogonal wave functions, we try to characterize the associated parent Hamiltonians, to see how the wave functions and the energy values affect the structure of the parent Hamiltonian. Specifically, we obtain (quasi) local Hamiltonians by a complete set of (multilayer) product states and a local mapping of the energy values to the wave functions. On the other hand, a complete set of tree wave functions (having a tree structure) results to nonlocal Hamiltonians and operators which flip simultaneously all the spins in a single branch of the tree graph. We observe that even for a given set of basis states, the energy spectrum can significantly change the nature of interactions in the Hamiltonian. These effects can be exploited in a quantum engineering problem optimizing an objective functional of the Hamiltonian.
A Study of Regional Wave Source Time Functions of Central Asian Earthquakes
NASA Astrophysics Data System (ADS)
Xie, J.; Perry, M. R.; Schult, F. R.; Wood, J.
2014-12-01
Despite the extensive use of seismic regional waves in seismic event identification and attenuation tomography, very little is known on how seismic sources radiate energy into these waves. For example, whether regional Lg wave has the same source spectrum as that of the local S has been questioned by Harr et al. and Frenkel et al. three decades ago; many current investigators assume source spectra in Lg, Sn, Pg, Pn and Lg coda waves have either the same or very similar corner frequencies, in contrast to local P and S spectra whose corner frequencies differ. The most complete information on how the finite source ruptures radiate energy into regional waves is contained in the time domain source time functions (STFs). To estimate the STFs of regional waves using the empirical Green's function (EGF) method, we have been substantially modifying a semi-automotive computer procedure to cope with the increasingly diverse and inconsistent naming patterns of new data files from the IRIS DMC. We are applying the modified procedure to many earthquakes in central Asia to study the STFs of various regional waves to see whether they have the same durations and pulse shapes, and how frequently source directivity occur. When applicable, we also examine the differences between STFs of local P and S waves and those of regional waves. The result of these analyses will be presented at the meeting.
Projector augmented-wave method: Application to relativistic spin-density functional theory
NASA Astrophysics Data System (ADS)
Dal Corso, Andrea
2010-08-01
Applying the projector augmented-wave (PAW) method to relativistic spin-density functional theory (RSDFT) we derive PAW Dirac-Kohn-Sham equations for four-component spinor pseudo-wave-functions. The PAW freedom to add a vanishing operator inside the PAW spheres allows us to transform these PAW Dirac-type equations into PAW Pauli-type equations for two-component spinor pseudo-wave-functions. With these wave functions, we get the frozen-core energy as well as the charge and magnetization densities of RSDFT, with errors comparable to the largest between 1/c2 and the transferability error of the PAW data sets. Presently, the latter limits the accuracy of the calculations, not the use of the Pauli-type equations. The theory is validated by applications to isolated atoms of Fe, Pt, and Au, and to the band structure of fcc-Pt, fcc-Au, and ferromagnetic bcc-Fe.
Racine, Julien; Hagebaum-Reignier, Denis; Carissan, Yannick; Humbel, Stéphane
2016-03-30
A method is proposed to obtain coefficients and weights of valence bond (VB) determinants from multi configurational wave functions. This reading of the wave functions can apply to ground states as well as excited states. The method is based on projection operators. Both energetic and overlap-based criteria are used to assess the quality of the resulting VB wave function. The approach gives a simple access to a VB rewriting for low-lying states, and it is applied to the allyl cation, to the allyl radical and to the ethene (notably to the V-state). For these states, large overlap between VB and multi reference wave functions are easily obtained. The approach proves to be useful to propose an interpretation of the nature of the V-state of ethene. PMID:26786547
Wave function for dissipative harmonically confined electrons in a time-dependent electric field
NASA Astrophysics Data System (ADS)
Lai, Meng-Yun; Pan, Xiao-Yin; Li, Yu-Qi
2016-07-01
We investigate the many-body wave function of a dissipative system of interacting particles confined by a harmonic potential and perturbed by a time-dependent spatially homogeneous electric field. Applying the method of Yu and Sun (1994), it is found that the wave function is comprised of a phase factor times the solution to the unperturbed time-dependent (TD) Schrödinger equation with the latter being translated by a time-dependent value that satisfies the classical damped driven equation of motion, plus an addition fluctuation term due to the Brownian motion. The wave function reduces to that of the Harmonic Potential Theorem (HPT) wave function in the absence of the dissipation. An example of application of the results derived is also given.
Second-Order Perturbation Theory for Generalized Active Space Self-Consistent-Field Wave Functions.
Ma, Dongxia; Li Manni, Giovanni; Olsen, Jeppe; Gagliardi, Laura
2016-07-12
A multireference second-order perturbation theory approach based on the generalized active space self-consistent-field (GASSCF) wave function is presented. Compared with the complete active space (CAS) and restricted active space (RAS) wave functions, GAS wave functions are more flexible and can employ larger active spaces and/or different truncations of the configuration interaction expansion. With GASSCF, one can explore chemical systems that are not affordable with either CASSCF or RASSCF. Perturbation theory to second order on top of GAS wave functions (GASPT2) has been implemented to recover the remaining electron correlation. The method has been benchmarked by computing the chromium dimer ground-state potential energy curve. These calculations show that GASPT2 gives results similar to CASPT2 even with a configuration interaction expansion much smaller than the corresponding CAS expansion. PMID:27276688
Approximate analytical time-domain Green's functions for the Caputo fractional wave equation.
Kelly, James F; McGough, Robert J
2016-08-01
The Caputo fractional wave equation [Geophys. J. R. Astron. Soc. 13, 529-539 (1967)] models power-law attenuation and dispersion for both viscoelastic and ultrasound wave propagation. The Caputo model can be derived from an underlying fractional constitutive equation and is causal. In this study, an approximate analytical time-domain Green's function is derived for the Caputo equation in three dimensions (3D) for power law exponents greater than one. The Green's function consists of a shifted and scaled maximally skewed stable distribution multiplied by a spherical spreading factor 1/(4πR). The approximate one dimensional (1D) and two dimensional (2D) Green's functions are also computed in terms of stable distributions. Finally, this Green's function is decomposed into a loss component and a diffraction component, revealing that the Caputo wave equation may be approximated by a coupled lossless wave equation and a fractional diffusion equation. PMID:27586735
Wave functions of symmetry-protected topological phases from conformal field theories
NASA Astrophysics Data System (ADS)
Scaffidi, Thomas; Ringel, Zohar
2016-03-01
We propose a method for analyzing two-dimensional symmetry-protected topological (SPT) wave functions using a correspondence with conformal field theories (CFTs) and integrable lattice models. This method generalizes the CFT approach for the fractional quantum Hall effect wherein the wave-function amplitude is written as a many-operator correlator in the CFT. Adopting a bottom-up approach, we start from various known microscopic wave functions of SPTs with discrete symmetries and show how the CFT description emerges at large scale, thereby revealing a deep connection between group cocycles and critical, sometimes integrable, models. We show that the CFT describing the bulk wave function is often also the one describing the entanglement spectrum, but not always. Using a plasma analogy, we also prove the existence of hidden quasi-long-range order for a large class of SPTs. Finally, we show how response to symmetry fluxes is easily described in terms of the CFT.
SURFACE SYMMETRY ENERGY OF NUCLEAR ENERGY DENSITY FUNCTIONALS
Nikolov, N; Schunck, N; Nazarewicz, W; Bender, M; Pei, J
2010-12-20
We study the bulk deformation properties of the Skyrme nuclear energy density functionals. Following simple arguments based on the leptodermous expansion and liquid drop model, we apply the nuclear density functional theory to assess the role of the surface symmetry energy in nuclei. To this end, we validate the commonly used functional parametrizations against the data on excitation energies of superdeformed band-heads in Hg and Pb isotopes, and fission isomers in actinide nuclei. After subtracting shell effects, the results of our self-consistent calculations are consistent with macroscopic arguments and indicate that experimental data on strongly deformed configurations in neutron-rich nuclei are essential for optimizing future nuclear energy density functionals. The resulting survey provides a useful benchmark for further theoretical improvements. Unlike in nuclei close to the stability valley, whose macroscopic deformability hangs on the balance of surface and Coulomb terms, the deformability of neutron-rich nuclei strongly depends on the surface-symmetry energy; hence, its proper determination is crucial for the stability of deformed phases of the neutron-rich matter and description of fission rates for r-process nucleosynthesis.
Spent Nuclear Fuel Project Canister Storage Building Functions and Requirements
KLEM, M.J.
2000-10-18
In 1998, a major change in the technical strategy for managing Multi Canister Overpacks (MCO) while stored within the Canister Storage Building (CSB) occurred. The technical strategy is documented in Baseline Change Request (BCR) No. SNF-98-006, Simplified SNF Project Baseline (MCO Sealing) (FDH 1998). This BCR deleted the hot conditioning process initially adopted for the Spent Nuclear Fuel Project (SNF Project) as documented in WHC-SD-SNF-SP-005, Integrated Process Strategy for K Basins Spent Nuclear Fuel (WHC 199.5). In summary, MCOs containing Spent Nuclear Fuel (SNF) from K Basins would be placed in interim storage following processing through the Cold Vacuum Drying (CVD) facility. With this change, the needs for the Hot Conditioning System (HCS) and inerting/pressure retaining capabilities of the CSB storage tubes and the MCO Handling Machine (MHM) were eliminated. Mechanical seals will be used on the MCOs prior to transport to the CSB. Covers will be welded on the MCOs for the final seal at the CSB. Approval of BCR No. SNF-98-006, imposed the need to review and update the CSB functions and requirements baseline documented herein including changing the document title to ''Spent Nuclear Fuel Project Canister Storage Building Functions and Requirements.'' This revision aligns the functions and requirements baseline with the CSB Simplified SNF Project Baseline (MCO Sealing). This document represents the Canister Storage Building (CSB) Subproject technical baseline. It establishes the functions and requirements baseline for the implementation of the CSB Subproject. The document is organized in eight sections. Sections 1.0 Introduction and 2.0 Overview provide brief introductions to the document and the CSB Subproject. Sections 3.0 Functions, 4.0 Requirements, 5.0 Architecture, and 6.0 Interfaces provide the data described by their titles. Section 7.0 Glossary lists the acronyms and defines the terms used in this document. Section 8.0 References lists the
NASA Astrophysics Data System (ADS)
Gitterman, Yefim; Kim, So Gu; Hofstetter, Abraham
2014-05-01
Two underground nuclear explosions conducted by North Korea in 2009 and 2013 were recorded by the Israel Seismic Network. Pronounced coherent minima (spectral nulls) at 1.2-1.3 Hz were revealed in the spectra of teleseismic P-waves. For a ground-truth explosion with a shallow source depth (relatively to an earthquake), this phenomenon can be interpreted in terms of the interference between the down-going P-wave and the pP phase reflected from the Earth's surface. A similar effect was observed at ISN stations for the Pakistan nuclear explosion at a different frequency 1.7 Hz indicating a source and not site-effect. Similar spectral minima with about the same frequency were observed in teleseismic P-waves of all three North Korea explosions (including the 2006 test) recorded at network stations and arrays in Kazakhstan (KURK), Norway (NORESS, ARCESS), Australia (Alice Springs, Warramunga) and Canada (Yellowknife), covering a broad azimuthal range. Data of the 2013 test at Warramunga array showed harmonic spectral modulation with several minima, evidencing a clear interference effect. These observations support the above-mentioned interpretation. Based on the null frequency dependency on the near-surface acoustic velocity and the source depth, the depth of the North Korea tests was estimated as ~2 km (different from the value ~1 km reported by USGS for the third test). This unusual depth estimation needs an additional validation based on more stations and verification by other methods.
sup 4 He- sup 4 He elastic scattering and variational wave functions
Usmani, A.A.; Ahmad, I. ); Usmani, Q.N. )
1992-01-01
We calculate differential cross sections for {sup 4}He-{sup 4}He elastic scattering at 4.32 GeV/{ital c} in the framework of Glauber multiple scattering theory using correlated variational wave functions as given by the two-nucleon Urbana {ital v}{sub 14} potential and the spin-isospin averaged Melfleit-Tjon force {ital V}. These wave functions are found to give fairly satisfactory results.
Miyake, Hirokazu; Siviloglou, Georgios A; Puentes, Graciana; Pritchard, David E; Ketterle, Wolfgang; Weld, David M
2011-10-21
We have observed Bragg scattering of photons from quantum degenerate ^{87}Rb atoms in a three-dimensional optical lattice. Bragg scattered light directly probes the microscopic crystal structure and atomic wave function whose position and momentum width is Heisenberg limited. The spatial coherence of the wave function leads to revivals in the Bragg scattered light due to the atomic Talbot effect. The decay of revivals across the superfluid to Mott insulator transition indicates the loss of superfluid coherence. PMID:22107532
Zhang, Y. S.; Cai, F.; Xu, W. M.
2011-09-28
The ship motion equation with a cosine wave excitement force describes the slip moments in regular waves. A new kind of wave excitement force model, with the form as sums of cosine functions was proposed to describe ship rolling in irregular waves. Ship rolling time series were obtained by solving the ship motion equation with the fourth-order-Runger-Kutta method. These rolling time series were synthetically analyzed with methods of phase-space track, power spectrum, primary component analysis, and the largest Lyapunove exponent. Simulation results show that ship rolling presents some chaotic characteristic when the wave excitement force was applied by sums of cosine functions. The result well explains the course of ship rolling's chaotic mechanism and is useful for ship hydrodynamic study.
NASA Astrophysics Data System (ADS)
Francisco, E.; Pendás, A. Martín; Blanco, M. A.
2008-04-01
Given an N-electron molecule and an exhaustive partition of the real space ( R) into m arbitrary regions Ω,Ω,…,Ω ( ⋃i=1mΩ=R), the edf program computes all the probabilities P(n,n,…,n) of having exactly n electrons in Ω, n electrons in Ω,…, and n electrons ( n+n+⋯+n=N) in Ω. Each Ω may correspond to a single basin (atomic domain) or several such basins (functional group). In the later case, each atomic domain must belong to a single Ω. The program can manage both single- and multi-determinant wave functions which are read in from an aimpac-like wave function description ( .wfn) file (T.A. Keith et al., The AIMPAC95 programs, http://www.chemistry.mcmaster.ca/aimpac, 1995). For multi-determinantal wave functions a generalization of the original .wfn file has been introduced. The new format is completely backwards compatible, adding to the previous structure a description of the configuration interaction (CI) coefficients and the determinants of correlated wave functions. Besides the .wfn file, edf only needs the overlap integrals over all the atomic domains between the molecular orbitals (MO). After the P(n,n,…,n) probabilities are computed, edf obtains from them several magnitudes relevant to chemical bonding theory, such as average electronic populations and localization/delocalization indices. Regarding spin, edf may be used in two ways: with or without a splitting of the P(n,n,…,n) probabilities into α and β spin components. Program summaryProgram title: edf Catalogue identifier: AEAJ_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEAJ_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 5387 No. of bytes in distributed program, including test data, etc.: 52 381 Distribution format: tar.gz Programming language: Fortran 77 Computer
Chiral Restoration in a Nuclear Medium ---Probed by S-Wave Pion Dynamics---
NASA Astrophysics Data System (ADS)
Kienle, P.
Using 500 MeV (d,^3He π^-) pion transfer reactions in recoil free kinematics, pionic 1s-states were populated in the ^{115,119,123}Sn isotopes and their binding energies and widths determined by precision missing mass spectroscopy. Using these data and corresponding ones from iso-scalar light nuclei nuclei, ^{16}O, ^{20}Ne and ^{28}Si, we determined the pion nucleus s-wave strength parameters, b_0, b_1, Re B_0, and Im B_0. By comparison of the iso-vector pion nucleon strength, determined from pionic hydrogen X-ray spectroscopy b_1^{free}, with the b_1 in a nuclear medium scaled to the density ρ(0), we deduced a scaling factor, the square of the pion decay constant in the vacuum and in nuclear medium, as R = b_1^{free} / b_1 = f^2_{π}(ρ_0)/f^2_{π} = 0.64. Thus from the observed increase of the pion s-wave iso-vector strength in a nuclear medium a reduction of f^2_{π}, the order parameter of chiral symme try breaking, is indicated in accordance with theoretical expectations. This finding is supported by recent π^+ and π^- scattering experiments. A short outlook is given on a future program at RIBF in RIKEN for precision studies of deeply bound 1s-states in heavy nuclei.
SAID Partial Wave Analyses from CNS DAC (Center for Nuclear Studies Data Analysis Center)
George Washington University (GW) has one of the largest university-based nuclear-physics groups in the nation. Many of the current and future projects are geared to Thomas Jefferson National Accelerator Facility (JLab) at Newport News, VA. JLab is the world's premier electron accelerator for nuclear physics, and GW is one of the charter members of the governing body of JLab, the Southeastern Universities Research Association (SURA). The George Washington Data Analysis Center (DAC) was created in 1998 by an agreement among the Department of Energy, Jefferson Lab, and the GW Center for Nuclear Studies.The activities of the DAC fall into four distinct categories: 1) Performing partial-wave analyses of fundamental two- and three-body reactions; 2) Maintenance of databases associated with these reactions; 3) Development of software to disseminate DAC results (as well as the results of competing model-independent analyses and potential approaches); and 4) Phenomenological and theoretical investigations which bridge the gap between theory and experiment; in particular, the extraction of N* and D * hadronic and electromagnetic couplings. Partial Wave Analyses (and the associated databases) available at GW are: Pion-Nucleon, Kaon-Nucleon, Nucleon-Nucleon, Pion Photoproduction, Pion Electroproduction, Kaon Photoproduction, Eta Photoproduction, Eta-Prime Photoproduction, Pion-Deuteron (elastic), and Pion-Deuteron to Proton+Proton. [Taken from http://www.gwu.edu/~ndl/dac.htm">http://www.gwu.edu/~ndl/dac.htm
Van Raemdonck, Mario; Alcoba, Diego R; Poelmans, Ward; De Baerdemacker, Stijn; Torre, Alicia; Lain, Luis; Massaccesi, Gustavo E; Van Neck, Dimitri; Bultinck, Patrick
2015-09-14
A class of polynomial scaling methods that approximate Doubly Occupied Configuration Interaction (DOCI) wave functions and improve the description of dynamic correlation is introduced. The accuracy of the resulting wave functions is analysed by comparing energies and studying the overlap between the newly developed methods and full configuration interaction wave functions, showing that a low energy does not necessarily entail a good approximation of the exact wave function. Due to the dependence of DOCI wave functions on the single-particle basis chosen, several orbital optimisation algorithms are introduced. An energy-based algorithm using the simulated annealing method is used as a benchmark. As a computationally more affordable alternative, a seniority number minimising algorithm is developed and compared to the energy based one revealing that the seniority minimising orbital set performs well. Given a well-chosen orbital basis, it is shown that the newly developed DOCI based wave functions are especially suitable for the computationally efficient description of static correlation and to lesser extent dynamic correlation. PMID:26374017
NASA Astrophysics Data System (ADS)
Van Raemdonck, Mario; Alcoba, Diego R.; Poelmans, Ward; De Baerdemacker, Stijn; Torre, Alicia; Lain, Luis; Massaccesi, Gustavo E.; Van Neck, Dimitri; Bultinck, Patrick
2015-09-01
A class of polynomial scaling methods that approximate Doubly Occupied Configuration Interaction (DOCI) wave functions and improve the description of dynamic correlation is introduced. The accuracy of the resulting wave functions is analysed by comparing energies and studying the overlap between the newly developed methods and full configuration interaction wave functions, showing that a low energy does not necessarily entail a good approximation of the exact wave function. Due to the dependence of DOCI wave functions on the single-particle basis chosen, several orbital optimisation algorithms are introduced. An energy-based algorithm using the simulated annealing method is used as a benchmark. As a computationally more affordable alternative, a seniority number minimising algorithm is developed and compared to the energy based one revealing that the seniority minimising orbital set performs well. Given a well-chosen orbital basis, it is shown that the newly developed DOCI based wave functions are especially suitable for the computationally efficient description of static correlation and to lesser extent dynamic correlation.
NASA Astrophysics Data System (ADS)
Mukherjee, Sutirtha; Mandal, Sudhansu
The internal structure and topology of the ground states for fractional quantum Hall effect (FQHE) are determined by the relative angular momenta between all the possible pairs of electrons. Laughlin wave function is the only known microscopic wave function for which these relative angular momenta are homogeneous (same) for any pair of electrons and depend solely on the filling factor. Without invoking any microscopic theory, considering only the relationship between number of flux quanta and particles in spherical geometry, and allowing the possibility of inhomogeneous (different) relative angular momenta between any two electrons, we develop a general method for determining a closed-form ground state wave function for any incompressible FQHE state. Our procedure provides variationally obtained very accurate wave functions, yet having simpler structure compared to any other known complex microscopic wave functions for the FQHE states. This method, thus, has potential in predicting a very accurate ground state wave function for the puzzling states such as the state at filling fraction 5/2. We acknowledge support from Department of Science and Technology, India.
Exactness of wave functions from two-body exponential transformations in many-body quantum theory
Mazziotti, David A.
2004-01-01
Recent studies have considered the possibility that the exact ground-state wavefunction from any Hamiltonian with two-particle interactions may be generated from a single finite two-body exponential transformation acting on an arbitrary Slater determinant [Piecuch et al., Phys. Rev. Lett. 90, 113001 (2003)]. Using the Campbell-Baker-Hausdorff relation, we show that it is difficult for the variational minimum of this trial wave function to satisfy the contracted Schroedinger equation which is a necessary and sufficient condition for the wave function to satisfy the Schroedinger equation. A counterexample is presented through the Lipkin quasispin model with 4-50 fermions. When the number of fermions exceeds four, the wave function from a finite two-body exponential transformation is shown to be inexact. If the trial wave function ansatz is extended to include products of finite two-body exponential transformations acting on an arbitrary Slater-determinant reference, then we show that the ansatz includes the exact ground-state wave function from any Hamiltonian with only two-particle interactions. Connections between the two-body exponential transformation of the wave function and recent research on two-body exponential similarity transformations of the Hamiltonian [S.R. White, J. Chem. Phys. 117, 7472 (2002)] are discussed.
Modeling the Pulse Signal by Wave-Shape Function and Analyzing by Synchrosqueezing Transform.
Wu, Hau-Tieng; Wu, Han-Kuei; Wang, Chun-Li; Yang, Yueh-Lung; Wu, Wen-Hsiang; Tsai, Tung-Hu; Chang, Hen-Hong
2016-01-01
We apply the recently developed adaptive non-harmonic model based on the wave-shape function, as well as the time-frequency analysis tool called synchrosqueezing transform (SST) to model and analyze oscillatory physiological signals. To demonstrate how the model and algorithm work, we apply them to study the pulse wave signal. By extracting features called the spectral pulse signature, and based on functional regression, we characterize the hemodynamics from the radial pulse wave signals recorded by the sphygmomanometer. Analysis results suggest the potential of the proposed signal processing approach to extract health-related hemodynamics features. PMID:27304979
Modeling the Pulse Signal by Wave-Shape Function and Analyzing by Synchrosqueezing Transform
Wang, Chun-Li; Yang, Yueh-Lung; Wu, Wen-Hsiang; Tsai, Tung-Hu; Chang, Hen-Hong
2016-01-01
We apply the recently developed adaptive non-harmonic model based on the wave-shape function, as well as the time-frequency analysis tool called synchrosqueezing transform (SST) to model and analyze oscillatory physiological signals. To demonstrate how the model and algorithm work, we apply them to study the pulse wave signal. By extracting features called the spectral pulse signature, and based on functional regression, we characterize the hemodynamics from the radial pulse wave signals recorded by the sphygmomanometer. Analysis results suggest the potential of the proposed signal processing approach to extract health-related hemodynamics features. PMID:27304979
A whole-space transform formula of cylindrical wave functions for scattering problems
NASA Astrophysics Data System (ADS)
Yuan, Xiaoming
2014-03-01
The theory of elastic wave scattering is a fundamental concept in the study of elastic dynamics and wave motion, and the wave function expansion technique has been widely used in many subjects. To supply the essential tools for solving wave scattering problems induced by an eccentric source or multi-sources as well as multi-scatters, a whole-space transform formula of cylindrical wave functions is presented and its applicability to some simple cases is demonstrated in this study. The transforms of wave functions in cylindrical coordinates can be classified into two basic types: interior transform and exterior transform, and the existing Graf's addition theorem is only suitable for the former. By performing a new replacement between the two coordinates, the exterior transform formula is first deduced. It is then combined with Graf's addition theorem to establish a whole-space transform formula. By using the whole-space transform formula, the scattering solutions by the sources outside and inside a cylindrical cavity are constructed as examples of its application. The effectiveness and advantages of the whole-space transform formula is illustrated by comparison with the approximate model based on a large cycle method. The whole-space transform formula presented herein can be used to perform the transform between two different cylindrical coordinates in the whole space. In addition, its concept and principle are universal and can be further extended to establish the coordinate transform formula of wave functions in other coordinate systems.
Surface-wave generation by underground nuclear explosions releasing tectonic strain
Patton, H.J.
1980-11-03
Seismic surface-wave generation by underground nuclear explosions releasing tectonic strain is studied through a series of synthetic radiation-pattern calculations based on the earthquake-trigger model. From amplitude and phase radiation patterns for 20-s Rayleigh waves, inferences are made about effects on surface-wave magnitude, M/sub s/, and waveform character. The focus of this study is a comparison between two mechanisms of tectonic strain release: strike-slip motion on vertical faults and thrust motion on 45/sup 0/ dipping faults. The results of our calculations show that Rayleigh-wave amplitudes of the dip-slip model at F values between 0.75 and 1.5 are significantly lower than amplitudes of the strike-slip model or of the explosion source alone. This effect translates into M/sub s/ values about 0.5 units lower than M/sub s/ of the explosion alone. Waveform polarity reversals occur in two of four azimuthal quadrants for the strike-slip model and in all azimuths of the dip-slip-thrust model for F values above about 3. A cursory examination of waveforms from presumed explosions in eastern Kazakhstan suggests that releases of tectonic strain are accompanying the detonation of many of these explosions. Qualitatively, the observations seem to favor the dip-slip-thrust model, which, in the case of a few explosions, must have F values above 3.
Yücel, Meryem A; Selb, Juliette; Aasted, Christopher M; Lin, Pei-Yi; Borsook, David; Becerra, Lino; Boas, David A
2016-08-01
Analysis of cerebral hemodynamics reveals a wide spectrum of oscillations ranging from 0.0095 to 2 Hz. While most of these oscillations can be filtered out during analysis of functional near-infrared spectroscopy (fNIRS) signals when estimating stimulus evoked hemodynamic responses, oscillations around 0.1 Hz are an exception. This is due to the fact that they share a common spectral range with typical stimulus evoked hemodynamic responses from the brain. Here we investigate the effect of hemodynamic oscillations around 0.1 Hz on the estimation of hemodynamic response functions from fNIRS data. Our results show that for an expected response of ~1 µM in oxygenated hemoglobin concentration (HbO), Mayer wave oscillations with an amplitude > ~1 µM at 0.1 Hz reduce the accuracy of the estimated response as quantified by a 3 fold increase in the mean squared error and decrease in correlation (R(2) below 0.78) when compared to the true HRF. These results indicate that the amplitude of oscillations at 0.1 Hz can serve as an objective metric of the expected HRF estimation accuracy. In addition, we investigated the effect of short separation regression on the recovered HRF, and found that this improves the recovered HRF when large amplitude 0.1 Hz oscillations are present in fNIRS data. We suspect that the development of other filtering strategies may provide even further improvement. PMID:27570699
Yücel, Meryem A.; Selb, Juliette; Aasted, Christopher M.; Lin, Pei-Yi; Borsook, David; Becerra, Lino; Boas, David A.
2016-01-01
Analysis of cerebral hemodynamics reveals a wide spectrum of oscillations ranging from 0.0095 to 2 Hz. While most of these oscillations can be filtered out during analysis of functional near-infrared spectroscopy (fNIRS) signals when estimating stimulus evoked hemodynamic responses, oscillations around 0.1 Hz are an exception. This is due to the fact that they share a common spectral range with typical stimulus evoked hemodynamic responses from the brain. Here we investigate the effect of hemodynamic oscillations around 0.1 Hz on the estimation of hemodynamic response functions from fNIRS data. Our results show that for an expected response of ~1 µM in oxygenated hemoglobin concentration (HbO), Mayer wave oscillations with an amplitude > ~1 µM at 0.1 Hz reduce the accuracy of the estimated response as quantified by a 3 fold increase in the mean squared error and decrease in correlation (R2 below 0.78) when compared to the true HRF. These results indicate that the amplitude of oscillations at 0.1 Hz can serve as an objective metric of the expected HRF estimation accuracy. In addition, we investigated the effect of short separation regression on the recovered HRF, and found that this improves the recovered HRF when large amplitude 0.1 Hz oscillations are present in fNIRS data. We suspect that the development of other filtering strategies may provide even further improvement. PMID:27570699
A study on pseudo interface wave technique for CRDM weld defects in nuclear power plants
NASA Astrophysics Data System (ADS)
Lee, Jaesun; Park, Junpil; Cho, Younho; Huh, Hyung; Park, Keun-Bae; Kim, Dong-Ok
2015-03-01
The nuclear power plant inspection is very important for the safety issue. However due to some radiation and geometric problems, the detection of CRDM(Control Rod Drive Mechanism) can be very difficult by using conventional Ultrasonic Testing method. Also the shrink fit boundary condition can also be an obstacle for the inspection in this paper, instead of conventional Ultrasonic Testing, guided wave was used for the detection of some complicated structures. The CRDM nozzle was installed in reactor head with perfect shrink fit condition by using stainless steel. The wave amplitude distribution on the circumferential direction was calculated with various boundary conditions and the experimental result shows a possibility of the defect detection on J-groove weld.
A study on pseudo interface wave technique for CRDM weld defects in nuclear power plants
Lee, Jaesun E-mail: jpp@pusan.ac.kr; Park, Junpil E-mail: jpp@pusan.ac.kr; Cho, Younho; Huh, Hyung E-mail: dokim@kaeri.re.kr; Park, Keun-Bae E-mail: dokim@kaeri.re.kr; Kim, Dong-Ok E-mail: dokim@kaeri.re.kr
2015-03-31
The nuclear power plant inspection is very important for the safety issue. However due to some radiation and geometric problems, the detection of CRDM(Control Rod Drive Mechanism) can be very difficult by using conventional Ultrasonic Testing method. Also the shrink fit boundary condition can also be an obstacle for the inspection in this paper, instead of conventional Ultrasonic Testing, guided wave was used for the detection of some complicated structures. The CRDM nozzle was installed in reactor head with perfect shrink fit condition by using stainless steel. The wave amplitude distribution on the circumferential direction was calculated with various boundary conditions and the experimental result shows a possibility of the defect detection on J-groove weld.
Relativistic spectral function of nucleons in hot nuclear matter
NASA Astrophysics Data System (ADS)
Ghosh, Sabyasachi; Sarkar, Sourav; Mallik, S.
2010-10-01
We present a simple calculation of the nucleon self-energy in nuclear matter at finite temperature in a relativistic framework, using the real-time thermal field theory. The imaginary parts of one-loop graphs are identified with discontinuities across the unitary and the Landau cuts. We find that in general both the cuts contribute significantly to the spectral function in the region of (virtual) nucleon mass usually considered, even though the unitary cut is ignored in the literature. Furthermore, our relativistic spectral function differs from the one in nonrelativistic approximation, used in some earlier calculations.
NASA Astrophysics Data System (ADS)
Bruntz, R. J.; Paxton, L. J.; Miller, E. S.; Bust, G. S.; Mayr, H. G.
2015-12-01
The Transfer Function Model (TFM) has been used in numerous studies to simulate gravity waves. In the TFM, the time dependence is formulated in terms of frequencies, and the horizontal wave pattern on the globe is formulated in terms of vector spherical harmonics. For a wide range of frequencies, the equations of mass, energy and momentum conservation are solved to compile a transfer function. The transfer function can then be easily combined with a time-dependent source whose spatial extent is also expressed in spherical harmonics, to produce a global atmospheric response, including gravity waves. This approach has significant benefits in that the solution is grid-independent (without any inherent limits on resolution), and the solutions do not suffer from singularities at the poles. We will show results from our simulations that couple the output of the TFM to an ionospheric model, to predict traveling ionospheric disturbances (TIDs) driven by the simulated gravity waves.
The effects of extracorporeal shock wave therapy on frozen shoulder patients’ pain and functions
Park, Chan; Lee, Sangyong; Yi, Chae-Woo; Lee, Kwansub
2015-01-01
[Purpose] The present study was conducted to examine the effects of extracorporeal shock wave therapy on frozen shoulder patients’ pain and functions. [Subjects] In the present study, 30 frozen shoulder patients were divided into two groups: an extracorporeal shock wave therapy group of 15 patients and a conservative physical therapy group of 15 patients. [Methods] Two times per week for six weeks, the extracorporeal shock wave therapy group underwent extracorporeal shock wave therapy, and the conservative physical therapy group underwent general physical therapy. Visual analog scales were used to measure frozen shoulder patients’ pain, and patient-specific functional scales were used to evaluate the degree of functional disorders. [Results] In intra-group comparisons, the two groups showed significant decreases in terms of visual analog scales and patient-specific functional scales, although the extracorporeal shock wave therapy group showed significantly lower scores than the conservative physical therapy group. [Conclusion] Extracorporeal shock wave therapy is considered an effective intervention for improving frozen shoulder patients’ pain and functions. PMID:26834326
Sun, Z.; Barnett, R.N.; Lester, W.A. Jr. )
1992-02-01
A wave function constructed as a product of a four-determinant function and a symmetric correlation function is employed in Monte Carlo computations of the ground-state energy of Li{sub 2} at {ital R}{sub {ital e}} = 5.05 Bohrs. Wave function parameters are determined by a fixed-sample minimization of deviations of the local energy. Although the variational Monte Carlo energy for this function lies, as expected, below that of a similar wave function constructed with a single determinant, the four-determinant function/correlation function wave function gives no improvement in quantum Monte Carlo energy. However, the unoptimized four-determinant function/correlation function wave function does yield an energy in excellent agreement with the estimated exact result. The poorer energy of the optimized function is caused by degradation of the nodal structure during parameter optimization.
Characteristics of seismic waves from Soviet peaceful nuclear explosions in salt
Adushkin, V.V.; Kaazik, P.B.; Kostyuchenko, V.N.; Kuznetsov, O.P.; Nedoshivin, N.I.; Rubinshtein, K.D.; Sultanov, D.D.
1995-04-01
The report is carried out by the Institute for Dynamics of the Geospheres, Russian Academy of Sciences under contract NB280344 with Lawrence Livermore National Laboratory, University of California. The work includes investigation of seismic waves generation and propagation from Soviet peaceful underground nuclear explosions in salt based on the data from temporary and permanent seismic stations. The explosions were conducted at the sites Azgir and Vega within the territory of the Caspian depression of the Russian platform. The data used were obtained in the following conditions of conduction: epicentral distance range from 0 to 60 degrees, yields from 1 to 65 kt and depths of burial from 160 to 1500 m.
Snieder, Roel
2004-04-01
The Green's function of waves that propagate between two receivers can be found by cross-correlating multiply scattered waves recorded at these receivers. This technique obviates the need for a source at one of these locations, and is therefore called "passive imaging." This principle has been explained by assuming that the normal modes of the system are uncorrelated and that all carry the same amount of energy (equipartitioning). Here I present an alternative derivation of passive imaging of the ballistic wave that is not based on normal modes. The derivation is valid for scalar waves in three dimensions, and for elastic surface waves. Passive imaging of the ballistic wave is based on the destructive interference of waves radiated from scatterers away from the receiver line, and the constructive interference of waves radiated from secondary sources near the receiver line. The derivation presented here shows that the global requirement of the equipartitioning of normal modes can be relaxed to the local requirement that the scattered waves propagate on average isotropically near the receivers. PMID:15169121
NASA Astrophysics Data System (ADS)
Rodgers, Arthur J.; Petersson, N. Anders; Sjogreen, Bjorn
2010-11-01
We performed high-resolution (8 Hz) three-dimensional simulations of ground motions from shallow explosions in the presence of rough surface topography near the North Korean nuclear test site to study elastic propagation effects with emphasis on theoretical aspects of shear wave generation. Interaction with rough topography causes significant P-to-Rg scattering along the surface with amplification of high-frequency (2-8 Hz) shear waves relative to the flat Earth case. Shear waves of different polarizations are coupled by topographic scattering. Rg precursors composed of P-to-Rg conversions traveling as surface waves have the spectral amplitudes comparable to the P wave, while the Rg phase has the low-frequency (0.5-3 Hz) spectral shape of the Rg from the flat case plus the high-frequency (3-8 Hz) P wave spectra. Motions at near-vertical takeoff angles corresponding to teleseismic propagation are increased or decreased indicating that waves are focused or defocused by topographic features above the source. Topographic roughness has a dramatic effect as short-wavelength features (<2-5 km) are included. Higher frequencies are amplified by topography, including frequencies corresponding to wavelengths shorter than the shortest topographic scale length. Overall topography enhances energy propagating along the surface near the source, amplifies surface waves, and tends to balance SV- and SH-polarized motions, all of which impact shear wave observations used for nuclear explosion monitoring. Further simulation studies could elucidate how the wavefield emerging from a topographically rough area ultimately propagates to regional and/or teleseismic distances.
Correlated Monte Carlo wave functions for the atoms He through Ne
Schmidt, K.E. ); Moskowitz, J.W. )
1990-09-15
We apply the variational Monte Carlo method to the atoms He through Ne. Our trial wave function is of the form introduced by Boys and Handy. We use the Monte Carlo method to calculate the first and second derivatives of an unreweighted variance and apply Newton's method to minimize this variance. We motivate the form of the correlation function using the local current conservation arguments of Feynman and Cohen. Using a self-consistent field wave function multiplied by a Boys and Handy correlation function, we recover a large fraction of the correlation energy of these atoms. We give the value of all variational parameters necessary to reproduce our wave functions. The method can be extended easily to other atoms and to molecules.
Wouters, L.F.
1960-08-30
Radiation waves can be detected by simultaneously measuring radiation- wave intensities at a plurality of space-distributed points and producing therefrom a plot of the wave intensity as a function of time. To this end. a detector system is provided which includes a plurality of nuclear radiation intensity detectors spaced at equal radial increments of distance from a source of nuclear radiation. Means are provided to simultaneously sensitize the detectors at the instant a wave of radiation traverses their positions. the detectors producing electrical pulses indicative of wave intensity. The system further includes means for delaying the pulses from the detectors by amounts proportional to the distance of the detectors from the source to provide an indication of radiation-wave intensity as a function of time.
Macieira-Coelho, E; Garcia-Alves, M; da Costa, B; Cantinho, G; Pedro, P; Dionisio, I; Gouveia, A; de Padua, F
1997-04-01
Controversy remains in considering non-Q wave myocardial infarction (NQMI) a distinct pathophysiological entity of Q wave myocardial infarction (QMI). In order to analyze the severity of coronary artery disease, extension of myocardial scar or myocardial ischemia and ventricular function, 78 consecutive patients with QMI and 32 with NQMI, mean age 55.4 +/- 8.5, not submitted to thrombolytic therapy, were studied. Coronary angiography, exercise thallium scintigraphy and radionuclide ventriculography were performed in all at least within 3 months of a prior myocardial infarction. In the present study the occurrence of QMI was significantly more frequent in older patients than NQMI. There was no prevalence of occlusion either in the right, left circumflex or left anterior descending coronary arteries in both groups. Ejection fraction, degree of occlusion and presence of collateral circulation showed an equal prevalence in QMI and NQMI patients. A higher incidence of multivessel disease was found in NQMI that had less necrosis than QMI patients. The prevalence of exercise induced thallium-201 redistribution defects within the infarct zone was substantially higher and involved more scar segments in NQMI patients. Physiological and clinical consequences of coronary thrombosis depends on the size and the number of diseased arteries, the approach the pathophysiologic consequences of coronary disease in terms of fractal structure has been suggested. A pronounced heterogeneity in regional myocardial blood flow in a fractal branching arterial network may be responsible for the pathophysiologic differences of coronary thrombosis between Q-wave and non Q-wave infarction. PMID:9341032
Completeness of the Coulomb Wave Functions in Quantum Mechanics
ERIC Educational Resources Information Center
Mukunda, N.
1978-01-01
Gives an explicit and elementary proof that the radial energy eigenfunctions for the hydrogen atom in quantum mechanics, bound and scattering states included, form a complete set. The proof uses some properties of the confluent hypergeometric functions and the Cauchy residue theorem from analytic function theory. (Author/GA)
Nuclear receptor corepressor complexes in cancer: mechanism, function and regulation
Wong, Madeline M; Guo, Chun; Zhang, Jinsong
2014-01-01
Nuclear receptor corepressor (NCoR) and silencing mediator for retinoid and thyroid hormone receptors (SMRT) function as corepressors for diverse transcription factors including nuclear receptors such as estrogen receptors and androgen receptors. Deregulated functions of NCoR and SMRT have been observed in many types of cancers and leukemias. NCoR and SMRT directly bind to transcription factors and nucleate the formation of stable complexes that include histone deacetylase 3, transducin b-like protein 1/TBL1-related protein 1, and G-protein pathway suppressor 2. These NCoR/SMRT-interacting proteins also show deregulated functions in cancers. In this review, we summarize the literature on the mechanism, regulation, and function of the core components of NCoR/SMRT complexes in the context of their involvement in cancers and leukemias. While the current studies support the view that the corepressors are promising targets for cancer treatment, elucidation of the mechanisms of corepressors involved in individual types of cancers is likely required for effective therapy. PMID:25374920
Proteolytic cleavage, trafficking, and functions of nuclear receptor tyrosine kinases.
Chen, Mei-Kuang; Hung, Mien-Chie
2015-10-01
Intracellular localization has been reported for over three-quarters of receptor tyrosine kinase (RTK) families in response to environmental stimuli. Internalized RTK may bind to non-canonical substrates and affect various cellular processes. Many of the intracellular RTKs exist as fragmented forms that are generated by γ-secretase cleavage of the full-length receptor, shedding, alternative splicing, or alternative translation initiation. Soluble RTK fragments are stabilized and intracellularly transported into subcellular compartments, such as the nucleus, by binding to chaperone or transcription factors, while membrane-bound RTKs (full-length or truncated) are transported from the plasma membrane to the ER through the well-established Rab- or clathrin adaptor protein-coated vesicle retrograde trafficking pathways. Subsequent nuclear transport of membrane-bound RTK may occur via two pathways, INFS or INTERNET, with the former characterized by release of receptors from the ER into the cytosol and the latter characterized by release of membrane-bound receptor from the ER into the nucleoplasm through the inner nuclear membrane. Although most non-canonical intracellular RTK signaling is related to transcriptional regulation, there may be other functions that have yet to be discovered. In this review, we summarize the proteolytic processing, intracellular trafficking and nuclear functions of RTKs, and discuss how they promote cancer progression, and their clinical implications. PMID:26096795
NASA Astrophysics Data System (ADS)
Shang, Xuefeng; de Hoop, Maarten V.; van der Hilst, Robert D.
2012-08-01
We present a wave equation prestack depth migration to image crust and mantle structures using multi-component earthquake data recorded at dense seismograph arrays. Transmitted P and S waves recorded on the surface are back propagated using an elastic wave equation solver. The wave modes are separated after the reverse-time continuation of the wavefield from the surface, and subjected to a (cross-correlation type) imaging condition forming an inverse scattering transform. Reverse time migration (RTM) does not make assumptions about the presence or properties of interfaces - notably, it does not assume that interfaces are (locally) horizontal. With synthetic experiments, and different background models, we show that passive source RTM can reconstruct dipping and vertically offset interfaces even in the presence of complex wave phenomena (such as caustics and point diffraction) and that its performance is superior to traditional receiver function analysis, e.g., common conversion point (CCP) stacking, in complex geological environments.
Fox, D.J.
1983-10-01
Analytic derivatives of the potential energy for Self-Consistent-Field (SCF) wave functions have been developed in recent years and found to be useful tools. The first derivative for configuration interaction (CI) wave functions is also available. This work details the extension of analytic methods to energy second derivatives for CI wave functions. The principal extension required for second derivatives is evaluation of the first order change in the CI wave function with respect to a nuclear perturbation. The shape driven graphical unitary group approach (SDGUGA) direct CI program was adapted to evaluate this term via the coupled-perturbed CI equations. Several iterative schemes are compared for use in solving these equations. The pilot program makes no use of molecular symmetry but the timing results show that utilization of molecular symmetry is desirable. The principles for defining and solving a set of symmetry adapted equations are discussed. Evaluation of the second derivative also requires the solution of the second order coupled-perturbed Hartree-Fock equations to obtain the correction to the molecular orbitals due to the nuclear perturbation. This process takes a consistently higher percentage of the computation time than for the first order equations alone and a strategy for its reduction is discussed.
A singularity free surface hopping expansion for the multistate wave function.
Herman, Michael F
2009-12-01
A version of a surface hopping wave function for nonadiabatic multistate problems, which is free of turning point singularities, is derived and tested. The primitive semiclassical form of the particular surface hopping method considered has been shown to be highly accurate, even for classically forbidden processes. However, this semiclassical wave function displays the usual singular behavior at turning points and caustics in the classical motion. Numerical data has shown that this somewhat reduces its accuracy when the energy is near the crossing energy of the diabatic electronic surfaces. The singularity free version of this surface hopping wave function is derived by partitioning the x-axis into a large number of small steps for one dimensional problems. The adiabatic electronic energy surfaces are approximated to be linear functions within each step. The matching conditions required by the continuity of the wave function and its derivative at each step boundary provide the needed conditions to obtain the amplitudes for changes in electronic state and/or reflection of the trajectory for the motion of the nuclei. This leads to a form of the surface hopping wave function that is free of turning point singularities. The method is tested for a one dimensional model problem, and it is found to be highly accurate at all energies considered, even when the energy is near the crossing energy. PMID:19968338
A spectral Phase-Amplitude method for propagating a wave function to large distances
NASA Astrophysics Data System (ADS)
Rawitscher, George
2015-06-01
The phase and amplitude (Ph-A) of a wave function vary slowly with distance, in contrast to the wave function that can be highly oscillatory. Hence the Ph-A representation of a wave function requires far fewer computational mesh points than the wave function itself. In 1930 Milne presented an equation for the phase and the amplitude functions (which is different from the one developed by Calogero), and in 1962 Seaton and Peach solved these equations iteratively. The objective of the present study is to implement Seaton and Peach's iteration procedure with a spectral Chebyshev expansion method, and at the same time present a non-iterative analytic solution to an approximate version of the iterative equations. The iterations converge rapidly for the case of attractive potentials. Two numerical examples are given: (1) for a potential that decreases with distance as 1 /r3, and (2) a Coulomb potential ∝ 1 / r. In both cases the whole radial range of [0-2000] requires only between 25 and 100 mesh points and the corresponding accuracy is between 10-3 and 10-6. The 0th iteration (which is the WKB approximation) gives an accuracy of 10-2. This spectral method permits one to calculate a wave function out to large distances reliably and economically.
NASA Astrophysics Data System (ADS)
Balram, Ajit C.; Jain, J. K.
2016-02-01
The microscopic wave functions of the composite fermion theory can incorporate electron mass anisotropy by a trivial rescaling of the coordinates. These wave functions are very likely adiabatically connected to the actual wave functions of the anisotropic fractional quantum Hall states. We show in this paper that they possess the nice property that their energies can be analytically related to the previously calculated energies for the isotropic states through a universal scale factor, thus allowing an estimation of several observables in the thermodynamic limit for all fractional quantum Hall states as well as the composite fermion Fermi sea. The rather weak dependence of the scale factor on the anisotropy provides insight into why fractional quantum Hall effect and composite fermions are quite robust to electron mass anisotropy. We discuss how better, though still approximate, wave functions can be obtained by introducing a variational parameter, following Haldane [F. D. M. Haldane, Phys. Rev. Lett. 107, 116801 (2011), 10.1103/PhysRevLett.107.116801], but the resulting wave functions are not readily amenable to calculations. Our considerations are also applicable, with minimal modification, to the case where the dielectric function of the background material is anisotropic.
Examples of Heun and Mathieu functions as solutions of wave equations in curved spaces
NASA Astrophysics Data System (ADS)
Birkandan, T.; Hortaçsu, M.
2007-02-01
We give examples of where the Heun function exists as solutions of wave equations encountered in general relativity. As a new example we find that while the Dirac equation written in the background of Nutku helicoid metric yields Mathieu functions as its solutions in four spacetime dimensions, the trivial generalization to five dimensions results in the double confluent Heun function. We reduce this solution to the Mathieu function with some transformations.
NASA Astrophysics Data System (ADS)
Murphy, Brian P.
1991-08-01
Waveform modeling of radial component receiver functions from ANMO (Albuquerque, New Mexico Observatory) for three source back azimuths (northwest, southeast, and southwest) was performed. The receiver functions were derived through source equalization deconvolution of merged long period and short period digital three component seismograms. Derived S-wave velocity models reflect dominantly intermediate composition granitic rock in the upper crust (above 15 km depth, Vs 3.5 km/sec) and middle crust (15-25 km depth, Vs 3.5-3.7 km/sec). Lower crustal shear velocities of approximately 3.75-3.85 km/sec may be representative of intermediate-to-mafic granulite facies, possibly together with previously underplated mafic material and other precursor crustal rocks. Shear wave attenuation between about 30-34 km may indicate a lower crustal partial melt zone. A 3-to-6 km thick interval is interpreted as a partial melt zone in the upper mantle leading into less depleted spinel peridotite (Vs = 4.25-4.35 km/sec) near 37 km. Inversion of EPT-ALQ interstation dispersion data for average S-wave velocity structure produces a satisfactory velocity tie to the middle and lower crust portions of the southwest back azimuth model.
Extracting a shape function for a signal with intra-wave frequency modulation.
Hou, Thomas Y; Shi, Zuoqiang
2016-04-13
In this paper, we develop an effective and robust adaptive time-frequency analysis method for signals with intra-wave frequency modulation. To handle this kind of signals effectively, we generalize our data-driven time-frequency analysis by using a shape function to describe the intra-wave frequency modulation. The idea of using a shape function in time-frequency analysis was first proposed by Wu (Wu 2013 Appl. Comput. Harmon. Anal. 35, 181-199. (doi:10.1016/j.acha.2012.08.008)). A shape function could be any smooth 2π-periodic function. Based on this model, we propose to solve an optimization problem to extract the shape function. By exploring the fact that the shape function is a periodic function with respect to its phase function, we can identify certain low-rank structure of the signal. This low-rank structure enables us to extract the shape function from the signal. Once the shape function is obtained, the instantaneous frequency with intra-wave modulation can be recovered from the shape function. We demonstrate the robustness and efficiency of our method by applying it to several synthetic and real signals. One important observation is that this approach is very stable to noise perturbation. By using the shape function approach, we can capture the intra-wave frequency modulation very well even for noise-polluted signals. In comparison, existing methods such as empirical mode decomposition/ensemble empirical mode decomposition seem to have difficulty in capturing the intra-wave modulation when the signal is polluted by noise. PMID:26953176
Yang, Feng-Ming; Lin, Yu-Chi; Hu, Meng-Chun
2011-04-01
Liver receptor homologue-1 (LRH-1) is a member of the nuclear receptor superfamily. We characterized two functional nuclear localization signals (NLSs) in LRH-1. NLS1 (residues 117-168) overlaps the second zinc finger in the DNA binding domain. Mutagenesis showed that the zinc finger structure and two basic clusters on either side of the zinc finger loop are critical for nuclear import of NLS1. NLS2 (residues 169-204) is located in the Ftz-F1 box that contains a bipartite signal. In full-length LRH-1, mutation of either NLS1 or NLS2 had no effect on nuclear localization, but disruption of both NLS1 and NLS2 resulted in the cytoplasmic accumulation of LRH-1. Either NLS1 or NLS2 alone was sufficient to target LRH-1 to the nucleus. Both NLS1 and NLS2 mediate nuclear transport by a mechanism involving importin α/β. Finally, we showed that three crucial basic clusters in the NLSs are involved in the DNA binding and transcriptional activities of LRH-1. PMID:20853131
Nuclear chiral and magnetic rotation in covariant density functional theory
NASA Astrophysics Data System (ADS)
Meng, Jie; Zhao, Pengwei
2016-05-01
Excitations of chiral rotation observed in triaxial nuclei and magnetic and/or antimagnetic rotations (AMR) seen in near-spherical nuclei have attracted a lot of attention. Unlike conventional rotation in well-deformed or superdeformed nuclei, here the rotational axis is not necessary coinciding with any principal axis of the nuclear density distribution. Thus, tilted axis cranking (TAC) is mandatory to describe these excitations self-consistently in the framework of covariant density functional theory (CDFT). We will briefly introduce the formalism of TAC–CDFT and its application for magnetic and AMR phenomena. Configuration-fixed CDFT and its predictions for nuclear chiral configurations and for favorable triaxial deformation parameters are also presented, and the discoveries of the multiple chiral doublets in 133Ce and 103Rh are discussed.
NASA Technical Reports Server (NTRS)
Baumeister, K. J.
1983-01-01
A time-dependent finite difference formulation to the inhomogeneous wave equation is derived for plane wave propagation with harmonic noise sources. The difference equation and boundary conditions are developed along with the techniques to simulate the Dirac delta function associated with a concentrated noise source. Example calculations are presented for the Green's function and distributed noise sources. For the example considered, the desired Fourier transformed acoustic pressures are determined from the transient pressures by use of a ramping function and an integration technique, both of which eliminates the nonharmonic pressure associated with the initial transient.
Recent results on nuclear structure functions for light nuclei
Kulagin, S. A.; Petti, R.
2011-09-21
We discuss the nuclear EMC effect with particular emphasis on recent data for light nuclei including {sup 2}H, {sup 3}He, {sup 4}He, {sup 9}Be, {sup 12}C and {sup 14}N. In order to verify the consistency of available data, we calculate the {chi}{sup 2} deviation between different data sets. We find a good agreement between the results from the NMC, SLAC E139, and HERMES experiments. However, our analysis indicates an overall normalization offset of about 2% in the data from the recent JLab E03-103 experiment with respect to previous data for nuclei heavier than {sup 3}He. We also discuss the extraction of the neutron/proton structure function ratio F{sub 2}{sup n}/F{sub 2}{sup p} from the nuclear ratios {sup 3}He/{sup 2}H and {sup 2}H/{sup 1}H. Our analysis shows that the E03-103 data on {sup 3}He/{sup 2}H require a renormalization of about 3% in order to be consistent with the F{sub 2}{sup n}/F{sub 2}{sup p} ratio obtained from the NMC experiment. After such a renormalization, the {sup 3}He data from the E03-103 data and HERMES experiments are in a good agreement. We also present a detailed comparison between data and model calculations, which include a description of the nuclear binding, Fermi motion and off-shell corrections to the structure functions of bound proton and neutron, as well as the nuclear pion and shadowing corrections.
Gross, Franz; Stadler, Alfred
2010-09-15
We present the effective range expansions for the {sup 1}S{sub 0} and {sup 3}S{sub 1} scattering phase shifts, and the relativistic deuteron wave functions that accompany our recent high precision fits (with {chi}{sup 2}/N{sub data{approx_equal}}1) to the 2007 world np data below 350 MeV. The wave functions are expanded in a series of analytical functions (with the correct asymptotic behavior at both large and small arguments) that can be Fourier-transformed from momentum to coordinate space and are convenient to use in any application. A fortran subroutine to compute these wave functions can be obtained from the authors.
Wave functions for quantum black hole formation in scalar field collapse
NASA Astrophysics Data System (ADS)
Bak, Dongsu; Kim, Sang Pyo; Kim, Sung Ku; Soh, Kwang-Sup; Yee, Jae Hyung
2000-02-01
We study quantum mechanically self-similar black hole formation by a collapsing scalar field and find the wave functions that give the correct semiclassical limit. In contrast with classical theory, the wave functions for black hole formation even in the supercritical case have not only incoming flux but also outgoing flux. From this result we compute the rate for black hole formation. In the subcritical case our result agrees with the semiclassical tunneling rate. Furthermore, we show how to recover the classical evolution of black hole formation from the wave function by defining the Hamilton-Jacobi characteristic function as W=ħ Im ln ψ. We find that the quantum-corrected apparent horizon deviates from the classical value only slightly without any qualitative change even in the critical case.
Duality between coordinates and wave functions on noncommutative space [rapid communication
NASA Astrophysics Data System (ADS)
Vancea, Ion V.
2004-02-01
The relation between coordinates and the solutions of the stationary Schrödinger equation in the noncommutative algebra of functions on R2 N is discussed. We derive this relation for a certain class of wave functions for which the quantum prepotentials depend linearly on the coordinates similarly to the commutative case. Also, the differential equation satisfied by the prepotentials is given.
Initial survey of the wave distribution functions for plasmaspheric hiss observed by ISEE 1
Storey, L.R.O. ); Lefeuvre, F.; Parrot, M.; Cairo, L. ); Anderson, R.R. )
1991-11-01
Multicomponent ELF/VLF wave data from the ISEE 1 satellite have been analyzed with the aim of identifying the generation mechanism of plasmaspheric hiss, and especially of determining whether it involves wave propagation of cyclic trajectories. The data were taken from four passes of the satellite, of which two were close to the geomagnetic equatorial plane and two were farther from it; all four occurred during magnetically quiet periods. The principal method of analysis was calculation of the wave distribution functions. The waves appear to have been generated over a wide range of altitudes within the plasmasphere, and most, though not all, of them were propagating obliquely with respect to the Earth's magnetic field. On one of the passes near the equator, some wave energy was observed at small wave normal angles, and these waves may have been propagating on cyclic trajectories. Even here, however, obliquely propagating waves were predominant, a finding that is difficult to reconcile with the classical quasi-linear generation mechanism or its variants. The conclusion is that another mechanism, probably nonlinear, must have been generating most of the hiss observed on these four passes.
Akhmediev, N; Soto-Crespo, J M; Devine, N
2016-08-01
Turbulence in integrable systems exhibits a noticeable scientific advantage: it can be expressed in terms of the nonlinear modes of these systems. Whether the majority of the excitations in the system are breathers or solitons defines the properties of the turbulent state. In the two extreme cases we can call such states "breather turbulence" or "soliton turbulence." The number of rogue waves, the probability density functions of the chaotic wave fields, and their physical spectra are all specific for each of these two situations. Understanding these extreme cases also helps in studies of mixed turbulent states when the wave field contains both solitons and breathers, thus revealing intermediate characteristics. PMID:27627303
Short-range correlations and the 3 s1 /2 wave function in 206Pb
NASA Astrophysics Data System (ADS)
Anders, M. R.; Shlomo, S.; Talmi, I.
2015-09-01
The charge-density difference between 206Pb and 205Tl , measured by elastic electron scattering, offers a unique opportunity to look for effects of short-range correlations on a shell-model wave function of a single proton. The measured difference is very similar to the charge density due to a proton in a 3 s1 /2 orbit. If there is a potential whose 3 s1 /2 wave function yields the measured difference between the charge distributions, no effect of short-range correlations is evident. To check this point, we look for a potential whose 3 s1 /2 wave function yields the measured data. We developed a novel method to obtain the potential directly from the density and its first and second derivatives. Fits to parametrized potentials were also carried out. The 3 s1 /2 wave functions of the potentials determined here reproduce fairly well the experimental data within the quoted errors. To detect possible effects of two-body correlations on the 3 s1 /2 shell-model wave function, more accurate measurements are required.
Torrezan, Antonio C; Han, Seong-Tae; Mastovsky, Ivan; Shapiro, Michael A; Sirigiri, Jagadishwar R; Temkin, Richard J; Barnes, Alexander B; Griffin, Robert G
2010-06-01
The design, operation, and characterization of a continuous-wave (CW) tunable second-harmonic 460-GHz gyrotron are reported. The gyrotron is intended to be used as a submillimeter-wave source for 700-MHz nuclear magnetic resonance experiments with sensitivity enhanced by dynamic nuclear polarization. The gyrotron operates in the whispering-gallery mode TE(11,2) and has generated 16 W of output power with a 13-kV 100-mA electron beam. The start oscillation current measured over a range of magnetic field values is in good agreement with theoretical start currents obtained from linear theory for successive high-order axial modes TE(11,2,q). The minimum start current is 27 mA. Power and frequency tuning measurements as a function of the electron cyclotron frequency have also been carried out. A smooth frequency tuning range of 1 GHz was obtained for the operating second-harmonic mode either by magnetic field tuning or beam voltage tuning. Long-term CW operation was evaluated during an uninterrupted period of 48 h, where the gyrotron output power and frequency were kept stable to within ±0.7% and ±6 ppm, respectively, by a computerized control system. Proper operation of an internal quasi-optical mode converter implemented to transform the operating whispering-gallery mode to a Gaussian-like beam was also verified. Based on the images of the gyrotron output beam taken with a pyroelectric camera, the Gaussian-like mode content of the output beam was computed to be 92% with an ellipticity of 12%. PMID:21243088
Torrezan, Antonio C; Han, Seong-Tae; Mastovsky, Ivan; Shapiro, Michael A; Sirigiri, Jagadishwar R; Temkin, Richard J; Griffin, Robert G; Barnes, Alexander B
2010-06-01
The design, operation, and characterization of a continuous-wave (CW) tunable second-harmonic 460-GHz gyrotron are reported. The gyrotron is intended to be used as a submillimeter-wave source for 700-MHz nuclear magnetic resonance experiments with sensitivity enhanced by dynamic nuclear polarization. The gyrotron operates in the whispering-gallery mode TE11,2 and has generated 16 W of output power with a 13-kV 100-mA electron beam. The start oscillation current measured over a range of magnetic field values is in good agreement with theoretical start currents obtained from linear theory for successive high-order axial modes TE11,2,q. The minimum start current is 27 mA. Power and frequency tuning measurements as a function of the electron cyclotron frequency have also been carried out. A smooth frequency tuning range of 1 GHz was obtained for the operating second-harmonic mode either by magnetic field tuning or beam voltage tuning. Long-term CW operation was evaluated during an uninterrupted period of 48 h, where the gyrotron output power and frequency were kept stable to within ±0.7% and ±6 ppm, respectively, by a computerized control system. Proper operation of an internal quasi-optical mode converter implemented to transform the operating whispering-gallery mode to a Gaussian-like beam was also verified. Based on the images of the gyrotron output beam taken with a pyroelectric camera, the Gaussian-like mode content of the output beam was computed to be 92% with an ellipticity of 12%. PMID:23761938
Torrezan, Antonio C.; Han, Seong-Tae; Mastovsky, Ivan; Shapiro, Michael A.; Sirigiri, Jagadishwar R.; Temkin, Richard J.; Barnes, Alexander B.; Griffin, Robert G.
2011-01-01
The design, operation, and characterization of a continuous-wave (CW) tunable second-harmonic 460-GHz gyrotron are reported. The gyrotron is intended to be used as a submillimeter-wave source for 700-MHz nuclear magnetic resonance experiments with sensitivity enhanced by dynamic nuclear polarization. The gyrotron operates in the whispering-gallery mode TE11,2 and has generated 16 W of output power with a 13-kV 100-mA electron beam. The start oscillation current measured over a range of magnetic field values is in good agreement with theoretical start currents obtained from linear theory for successive high-order axial modes TE11,2,q. The minimum start current is 27 mA. Power and frequency tuning measurements as a function of the electron cyclotron frequency have also been carried out. A smooth frequency tuning range of 1 GHz was obtained for the operating second-harmonic mode either by magnetic field tuning or beam voltage tuning. Long-term CW operation was evaluated during an uninterrupted period of 48 h, where the gyrotron output power and frequency were kept stable to within ±0.7% and ±6 ppm, respectively, by a computerized control system. Proper operation of an internal quasi-optical mode converter implemented to transform the operating whispering-gallery mode to a Gaussian-like beam was also verified. Based on the images of the gyrotron output beam taken with a pyroelectric camera, the Gaussian-like mode content of the output beam was computed to be 92% with an ellipticity of 12%. PMID:21243088
Torrezan, Antonio C.; Han, Seong-Tae; Mastovsky, Ivan; Shapiro, Michael A.; Sirigiri, Jagadishwar R.; Temkin, Richard J.; Griffin, Robert G.; Barnes, Alexander B.
2012-01-01
The design, operation, and characterization of a continuous-wave (CW) tunable second-harmonic 460-GHz gyrotron are reported. The gyrotron is intended to be used as a submillimeter-wave source for 700-MHz nuclear magnetic resonance experiments with sensitivity enhanced by dynamic nuclear polarization. The gyrotron operates in the whispering-gallery mode TE11,2 and has generated 16 W of output power with a 13-kV 100-mA electron beam. The start oscillation current measured over a range of magnetic field values is in good agreement with theoretical start currents obtained from linear theory for successive high-order axial modes TE11,2,q. The minimum start current is 27 mA. Power and frequency tuning measurements as a function of the electron cyclotron frequency have also been carried out. A smooth frequency tuning range of 1 GHz was obtained for the operating second-harmonic mode either by magnetic field tuning or beam voltage tuning. Long-term CW operation was evaluated during an uninterrupted period of 48 h, where the gyrotron output power and frequency were kept stable to within ±0.7% and ±6 ppm, respectively, by a computerized control system. Proper operation of an internal quasi-optical mode converter implemented to transform the operating whispering-gallery mode to a Gaussian-like beam was also verified. Based on the images of the gyrotron output beam taken with a pyroelectric camera, the Gaussian-like mode content of the output beam was computed to be 92% with an ellipticity of 12%. PMID:23761938
Meng, Fanchi; Na, Insung; Kurgan, Lukasz; Uversky, Vladimir N.
2015-01-01
The cell nucleus contains a number of membrane-less organelles or intra-nuclear compartments. These compartments are dynamic structures representing liquid-droplet phases which are only slightly denser than the bulk intra-nuclear fluid. They possess different functions, have diverse morphologies, and are typically composed of RNA (or, in some cases, DNA) and proteins. We analyzed 3005 mouse proteins localized in specific intra-nuclear organelles, such as nucleolus, chromatin, Cajal bodies, nuclear speckles, promyelocytic leukemia (PML) nuclear bodies, nuclear lamina, nuclear pores, and perinuclear compartment and compared them with ~29,863 non-nuclear proteins from mouse proteome. Our analysis revealed that intrinsic disorder is enriched in the majority of intra-nuclear compartments, except for the nuclear pore and lamina. These compartments are depleted in proteins that lack disordered domains and enriched in proteins that have multiple disordered domains. Moonlighting proteins found in multiple intra-nuclear compartments are more likely to have multiple disordered domains. Protein-protein interaction networks in the intra-nuclear compartments are denser and include more hubs compared to the non-nuclear proteins. Hubs in the intra-nuclear compartments (except for the nuclear pore) are enriched in disorder compared with non-nuclear hubs and non-nuclear proteins. Therefore, our work provides support to the idea of the functional importance of intrinsic disorder in the cell nucleus and shows that many proteins associated with sub-nuclear organelles in nuclei of mouse cells are enriched in disorder. This high level of disorder in the mouse nuclear proteins defines their ability to serve as very promiscuous binders, possessing both large quantities of potential disorder-based interaction sites and the ability of a single such site to be involved in a large number of interactions. PMID:26712748
Nuclear clustering in the energy density functional approach
Ebran, J.-P.; Khan, E.; Nikšić, T.; Vretenar, D.
2015-10-15
Nuclear Energy Density Functionals (EDFs) are a microscopic tool of choice extensively used over the whole chart to successfully describe the properties of atomic nuclei ensuing from their quantum liquid nature. In the last decade, they also have proved their ability to deal with the cluster phenomenon, shedding a new light on its fundamental understanding by treating on an equal footing both quantum liquid and cluster aspects of nuclei. Such a unified microscopic description based on nucleonic degrees of freedom enables to tackle the question pertaining to the origin of the cluster phenomenon and emphasizes intrinsic mechanisms leading to the emergence of clusters in nuclei.
Nuclear clustering in the energy density functional approach
NASA Astrophysics Data System (ADS)
Ebran, J.-P.; Khan, E.; Nikšić, T.; Vretenar, D.
2015-10-01
Nuclear Energy Density Functionals (EDFs) are a microscopic tool of choice extensively used over the whole chart to successfully describe the properties of atomic nuclei ensuing from their quantum liquid nature. In the last decade, they also have proved their ability to deal with the cluster phenomenon, shedding a new light on its fundamental understanding by treating on an equal footing both quantum liquid and cluster aspects of nuclei. Such a unified microscopic description based on nucleonic degrees of freedom enables to tackle the question pertaining to the origin of the cluster phenomenon and emphasizes intrinsic mechanisms leading to the emergence of clusters in nuclei.
Characterization/Selection of a Continuous Wave Laser for RIMS Analysis in Nuclear Forensics
NASA Astrophysics Data System (ADS)
Lau, Sunny; Alves, F.; Karunasiri, G.; Smith, C.; Isselhardt, B.
2015-03-01
The effort to implement the technology of resonance ionization mass spectroscopy (RIMS) to problems of nuclear forensics involves the use of multiple lasers to selectively ionize the elements of concern. While current systems incorporate pulsed lasers, we present the results of a feasibility study to determine alternative (Continuous Wave) laser technologies to be employed for analysis of the actinides and fission products of debris from a nuclear detonation. RIMS has the potential to provide rapid isotope ratio quantification of the actinides and important fission products for post detonation nuclear forensics. The current approach to ionize uranium and plutonium uses three Ti-Sapphire pulsed lasers capable of a fundamental wavelength range of 700-1000 nm. In this work, we describe the use of a COTS CW laser to replace one of the pulsed lasers used for the second resonance excitation step of plutonium near 847.282 nm. We characterize the critical laser parameters necessary to achieve high precision isotope ratio measurements including the stability over time of the mean wavelength, bandwidth and spectral mode purity. This far narrower bandwidth laser provides a simpler setup, more robust hardware (greater mobility), and more efficient use of laser irradiance.
Electronic structure and correlated wave functions of a few electron quantum dots
Sako, Tokuei; Ishida, Hiroshi; Fujikawa, Kazuo
2015-01-22
The energy spectra and wave functions of a few electrons confined by a quasi-one-dimensional harmonic and anharmonic potentials have been studied by using a full configuration interaction method employing a Cartesian anisotropic Gaussian basis set. The energy spectra are classified into three regimes of the strength of confinement, namely, large, medium and small. The polyad quantum number defined by a total number of nodes in the wave functions is shown to be a key ingredient to interpret the energy spectra for the whole range of the confinement strength. The nodal pattern of the wave functions exhibits normal modes for the harmonic confining potential, indicating collective motions of electrons. These normal modes are shown to undergo a transition to local modes for an anharmonic potential with large anharmonicity.
NASA Astrophysics Data System (ADS)
Casanova, David; Krylov, Anna I.
2016-01-01
A new method for quantifying the contributions of local excitation, charge resonance, and multiexciton configurations in correlated wave functions of multichromophoric systems is presented. The approach relies on fragment-localized orbitals and employs spin correlators. Its utility is illustrated by calculations on model clusters of hydrogen, ethylene, and tetracene molecules using adiabatic restricted-active-space configuration interaction wave functions. In addition to the wave function analysis, this approach provides a basis for a simple state-specific energy correction accounting for insufficient description of electron correlation. The decomposition scheme also allows one to compute energies of the diabatic states of the local excitonic, charge-resonance, and multi-excitonic character. The new method provides insight into electronic structure of multichromophoric systems and delivers valuable reference data for validating excitonic models.
Accuracy of electronic wave functions in quantum Monte Carlo: The effect of high-order correlations
NASA Astrophysics Data System (ADS)
Huang, Chien-Jung; Umrigar, C. J.; Nightingale, M. P.
1997-08-01
Compact and accurate wave functions can be constructed by quantum Monte Carlo methods. Typically, these wave functions consist of a sum of a small number of Slater determinants multiplied by a Jastrow factor. In this paper we study the importance of including high-order, nucleus-three-electron correlations in the Jastrow factor. An efficient algorithm based on the theory of invariants is used to compute the high-body correlations. We observe significant improvements in the variational Monte Carlo energy and in the fluctuations of the local energies but not in the fixed-node diffusion Monte Carlo energies. Improvements for the ground states of physical, fermionic atoms are found to be smaller than those for the ground states of fictitious, bosonic atoms, indicating that errors in the nodal surfaces of the fermionic wave functions are a limiting factor.
Coupled-channel effects for the bottomonium with realistic wave functions
NASA Astrophysics Data System (ADS)
Lu, Yu; Anwar, Muhammad Naeem; Zou, Bing-Song
2016-08-01
With Gaussian expansion method (GEM), realistic wave functions are used to calculate coupled-channel effects for the bottomonium under the framework of 3P0 model. The simplicity and accuracy of GEM are explained. We calculate the mass shifts, probabilities of the B meson continuum, S -D mixing angles, strong and dielectric decay widths. Our calculation shows that both S -D mixing and the B meson continuum can contribute to the suppression of the vector meson's dielectric decay width. We suggest more precise measurements on the radiative decays of ϒ (10580 ) and ϒ (11020 ) to distinguish these two effects. The above quantities are also calculated with simple harmonic oscillator (SHO) wave function approximation for comparison. The deviation between GEM and SHO indicates that it is essential to treat the wave functions accurately for near threshold states.
Application of Coulomb Wave Function DVR to Atomic Systems in Strong Laser Fields
NASA Astrophysics Data System (ADS)
Peng, Liang-You; Starace, Anthony F.
2006-05-01
We present an efficient and accurate grid method for solving the time-dependent Schr"odinger equation (TDSE) for atomic systems interacting with short laser pulses. The radial part of the wave function is expanded in a DVR (Discrete Variable Representation) basis constructed from the positive energy Coulomb wave function. The time propagation of the wave function is implemented using the well-known Arnoldi method. Compared with the usual finite difference (FD) discretization scheme for the radial coordinate, this method requires fewer grid points and handles naturally the Coulomb singularity at the origin. As examples, the method is shown to give accurate ionization rates for both H and H^- over a wide range of laser parameters.
Symmetric multivariate polynomials as a basis for three-boson light-front wave functions.
Chabysheva, Sophia S; Elliott, Blair; Hiller, John R
2013-12-01
We develop a polynomial basis to be used in numerical calculations of light-front Fock-space wave functions. Such wave functions typically depend on longitudinal momentum fractions that sum to unity. For three particles, this constraint limits the two remaining independent momentum fractions to a triangle, for which the three momentum fractions act as barycentric coordinates. For three identical bosons, the wave function must be symmetric with respect to all three momentum fractions. Therefore, as a basis, we construct polynomials in two variables on a triangle that are symmetric with respect to the interchange of any two barycentric coordinates. We find that, through the fifth order, the polynomial is unique at each order, and, in general, these polynomials can be constructed from products of powers of the second- and third-order polynomials. The use of such a basis is illustrated in a calculation of a light-front wave function in two-dimensional ϕ(4) theory; the polynomial basis performs much better than the plane-wave basis used in discrete light-cone quantization. PMID:24483584
Selected Interventions in Nuclear Medicine: Gastrointestinal Motor Functions
Odunsi, Suwebatu T.; Camilleri, Michael
2009-01-01
Measurement of gastrointestinal functions by scintigraphy is established in clinical practice and research. The most commonly used test is the gastric emptying test. This is acknowledged as the gold standard and is conducted according to a consensus statement from the national nuclear medicine and motility societies. Other techniques are somewhat more esoteric (e.g. measurement of gastric accommodation with SPECT) or the scintigraphic approach is not the acknowledged gold standard (e.g. colonic transit, recto-anal angle and emptying, esophageal transit). The performance characteristics of many of the scintigraphic measurements have been published and the pros and cons established in the literature. Gastrointestinal scintigraphy is an integral and important component of the assessment of gastrointestinal function. PMID:19341838
Next Generation Nuclear Plant Resilient Control System Functional Analysis
Lynne M. Stevens
2010-07-01
Control Systems and their associated instrumentation must meet reliability, availability, maintainability, and resiliency criteria in order for high temperature gas-cooled reactors (HTGRs) to be economically competitive. Research, perhaps requiring several years, may be needed to develop control systems to support plant availability and resiliency. This report functionally analyzes the gaps between traditional and resilient control systems as applicable to HTGRs, which includes the Next Generation Nuclear Plant; defines resilient controls; assesses the current state of both traditional and resilient control systems; and documents the functional gaps existing between these two controls approaches as applicable to HTGRs. This report supports the development of an overall strategy for applying resilient controls to HTGRs by showing that control systems with adequate levels of resilience perform at higher levels, respond more quickly to disturbances, increase operational efficiency, and increase public protection.
Global NLO Analysis of Nuclear Parton Distribution Functions
Hirai, M.; Kumano, S.; Nagai, T.-H.
2008-02-21
Nuclear parton distribution functions (NPDFs) are determined by a global analysis of experimental measurements on structure-function ratios F{sub 2}{sup A}/F{sub 2}{sup A{sup '}} and Drell-Yan cross section ratios {sigma}{sub DY}{sup A}/{sigma}{sub DY}{sup A{sup '}}, and their uncertainties are estimated by the Hessian method. The NPDFs are obtained in both leading order (LO) and next-to-leading order (NLO) of {alpha}{sub s}. As a result, valence-quark distributions are relatively well determined, whereas antiquark distributions at x>0.2 and gluon distributions in the whole x region have large uncertainties. The NLO uncertainties are slightly smaller than the LO ones; however, such a NLO improvement is not as significant as the nucleonic case.
Automatic determination of important mode-mode correlations in many-mode vibrational wave functions
NASA Astrophysics Data System (ADS)
König, Carolin; Christiansen, Ove
2015-04-01
We introduce new automatic procedures for parameterizing vibrational coupled cluster (VCC) and vibrational configuration interaction wave functions. Importance measures for individual mode combinations in the wave function are derived based on upper bounds to Hamiltonian matrix elements and/or the size of perturbative corrections derived in the framework of VCC. With a threshold, this enables an automatic, system-adapted way of choosing which mode-mode correlations are explicitly parameterized in the many-mode wave function. The effect of different importance measures and thresholds is investigated for zero-point energies and infrared spectra for formaldehyde and furan. Furthermore, the direct link between important mode-mode correlations and coordinates is illustrated employing water clusters as examples: Using optimized coordinates, a larger number of mode combinations can be neglected in the correlated many-mode vibrational wave function than with normal coordinates for the same accuracy. Moreover, the fraction of important mode-mode correlations compared to the total number of correlations decreases with system size. This underlines the potential gain in efficiency when using optimized coordinates in combination with a flexible scheme for choosing the mode-mode correlations included in the parameterization of the correlated many-mode vibrational wave function. All in all, it is found that the introduced schemes for parameterizing correlated many-mode vibrational wave functions lead to at least as systematic and accurate calculations as those using more standard and straightforward excitation level definitions. This new way of defining approximate calculations offers potential for future calculations on larger systems.
Orthogonality of embedded wave functions for different states in frozen-density embedding theory.
Zech, Alexander; Aquilante, Francesco; Wesolowski, Tomasz A
2015-10-28
Other than lowest-energy stationary embedded wave functions obtained in Frozen-Density Embedding Theory (FDET) [T. A. Wesolowski, Phys. Rev. A 77, 012504 (2008)] can be associated with electronic excited states but they can be mutually non-orthogonal. Although this does not violate any physical principles--embedded wave functions are only auxiliary objects used to obtain stationary densities--working with orthogonal functions has many practical advantages. In the present work, we show numerically that excitation energies obtained using conventional FDET calculations (allowing for non-orthogonality) can be obtained using embedded wave functions which are strictly orthogonal. The used method preserves the mathematical structure of FDET and self-consistency between energy, embedded wave function, and the embedding potential (they are connected through the Euler-Lagrange equations). The orthogonality is built-in through the linearization in the embedded density of the relevant components of the total energy functional. Moreover, we show formally that the differences between the expectation values of the embedded Hamiltonian are equal to the excitation energies, which is the exact result within linearized FDET. Linearized FDET is shown to be a robust approximation for a large class of reference densities. PMID:26520497
Orthogonality of embedded wave functions for different states in frozen-density embedding theory
Zech, Alexander; Wesolowski, Tomasz A.; Aquilante, Francesco
2015-10-28
Other than lowest-energy stationary embedded wave functions obtained in Frozen-Density Embedding Theory (FDET) [T. A. Wesolowski, Phys. Rev. A 77, 012504 (2008)] can be associated with electronic excited states but they can be mutually non-orthogonal. Although this does not violate any physical principles — embedded wave functions are only auxiliary objects used to obtain stationary densities — working with orthogonal functions has many practical advantages. In the present work, we show numerically that excitation energies obtained using conventional FDET calculations (allowing for non-orthogonality) can be obtained using embedded wave functions which are strictly orthogonal. The used method preserves the mathematical structure of FDET and self-consistency between energy, embedded wave function, and the embedding potential (they are connected through the Euler-Lagrange equations). The orthogonality is built-in through the linearization in the embedded density of the relevant components of the total energy functional. Moreover, we show formally that the differences between the expectation values of the embedded Hamiltonian are equal to the excitation energies, which is the exact result within linearized FDET. Linearized FDET is shown to be a robust approximation for a large class of reference densities.
Bredtmann, Timm; Chelkowski, Szczepan; Bandrauk, Andre D.
2011-08-15
A pump-probe scheme for preparing and monitoring electron-nuclear motion in a dissociative coherent electron-nuclear wave packet is explored from numerical solutions of a non-Born-Oppenheimer time-dependent Schroedinger equation. A mid-ir intense few-cycle probe pulse is used to generate molecular high-order-harmonic generation (MHOHG) from a coherent superposition of two or more dissociative coherent electronic-nuclear wave packets, prepared by a femtosecond uv pump pulse. Varying the time delay between the intense ir probe pulse and the uv pump pulse by a few hundreds of attoseconds, the MHOHG signal intensity is shown to vary by orders of magnitude, thus showing the high sensitivity to electron-nuclear dynamics in coherent electron-nuclear wave packets. We relate this high sensitivity of MHOHG spectra to opposing electron velocities (fluxes) in the electron wave packets of the recombining (recolliding) ionized electron and of the bound electron in the initial coherent superposition of two electronic states.
Ergler, Th.; Rudenko, A.; Zrost, K.; Schroeter, C. D.; Moshammer, R.; Ullrich, J.; Feuerstein, B.
2006-11-10
We report on a real-time imaging of the ultrafast D{sub 2}{sup +} rovibrational nuclear wave-packet motion performed using a combination of a pump-probe setup with 7 fs laser pulses and a 'reaction-microscope' spectrometer. We observe fast dephasing (collapse) of the vibrational wave packet and its subsequent revival and prove rotational excitation in ultrashort laser pulses. Channel-selective Fourier analysis of the wave packet's long-term ({approx}3000 fs) evolution allows us to resolve its individual constituents, revealing unique information on the mechanisms of strong-field ionization and dissociation.
NASA Astrophysics Data System (ADS)
Huang, Chao-Chun; Wang, Daw-Wei; Wu, Wen-Chin
2010-04-01
We investigate the condensate wave function and elementary excitations of strongly interacting bosonic polar molecules in a harmonic trap, treating the scattering amplitude beyond the standard first Born approximation (FBA). By using an appropriate trial wave function in the variational method, effects of the leading-order correction beyond the FBA have been investigated and shown to be significantly enhanced when the system is close to the phase boundary of collapse. How such a leading-order effect of going beyond the FBA can be observed in a realistic experiment is also discussed.
Spectra and decay rates of bb¯ meson using Gaussian wave function
NASA Astrophysics Data System (ADS)
Rai, Ajay Kumar; Devlani, Nayneshkumar; Kher, Virendrasinh H.
2015-05-01
Using the Gaussian wave function mass spectra and decay rates of bb¯ meson are investigated in the framework of phenomenological quark anti-quark potential (coulomb plus power) model consisting of relativistic corrections to the kinetic energy term. The spin-spin, spin-orbit and tensor interactions are employed to obtain the pseudoscalar and vector meson masses. The decay constants (fP/V) are computed using the wave function at the origin. The di-gamma and di-leptonic decays of the bb¯ meson are investigated using Van-Rayan Weisskopf formula as well as in the NRQCD formalism.
NASA Astrophysics Data System (ADS)
Reinhard, P.-G.; Nazarewicz, W.
2016-05-01
Background: Radii of charge and neutron distributions are fundamental nuclear properties. They depend on both nuclear interaction parameters related to the equation of state of infinite nuclear matter and on quantal shell effects, which are strongly impacted by the presence of nuclear surface. Purpose: In this work, by studying the correlation of charge and neutron radii, and neutron skin, with nuclear matter parameters, we assess different mechanisms that drive nuclear sizes. Method: We apply nuclear density functional theory using a family of Skyrme functionals obtained by means of optimization protocols, which do not include any radius information. By performing the Monte Carlo sampling of reasonable functionals around the optimal parametrization, we scan all correlations between nuclear matter properties and observables characterizing charge and neutron distributions of spherical closed-shell nuclei 48Ca,208Pb, and 298Fl. Results: By considering the influence of various nuclear matter properties on charge and neutron radii in a multidimensional parameter space of Skyrme functionals, we demonstrate the existence of two strong relationships: (i) between the nuclear charge radii and the saturation density of symmetric nuclear matter ρ0, and (ii) between the neutron skins and the slope of the symmetry energy L . The impact of other nuclear matter properties on nuclear radii is weak or nonexistent. For functionals optimized to experimental binding energies only, proton and neutron radii are found to be weakly correlated due to canceling trends from different nuclear matter characteristics. Conclusion: The existence of only two strong relations connecting nuclear radii with nuclear matter properties has important consequences. First, by requiring that the nuclear functional reproduces the empirical saturation point of symmetric nuclear matter practically fixes the charge (or proton) radii, and vice versa. This explains the recent results of ab initio calculations
Probability Density Function for Waves Propagating in a Straight PEC Rough Wall Tunnel
Pao, H
2004-11-08
The probability density function for wave propagating in a straight perfect electrical conductor (PEC) rough wall tunnel is deduced from the mathematical models of the random electromagnetic fields. The field propagating in caves or tunnels is a complex-valued Gaussian random processing by the Central Limit Theorem. The probability density function for single modal field amplitude in such structure is Ricean. Since both expected value and standard deviation of this field depend only on radial position, the probability density function, which gives what is the power distribution, is a radially dependent function. The radio channel places fundamental limitations on the performance of wireless communication systems in tunnels and caves. The transmission path between the transmitter and receiver can vary from a simple direct line of sight to one that is severely obstructed by rough walls and corners. Unlike wired channels that are stationary and predictable, radio channels can be extremely random and difficult to analyze. In fact, modeling the radio channel has historically been one of the more challenging parts of any radio system design; this is often done using statistical methods. In this contribution, we present the most important statistic property, the field probability density function, of wave propagating in a straight PEC rough wall tunnel. This work only studies the simplest case--PEC boundary which is not the real world but the methods and conclusions developed herein are applicable to real world problems which the boundary is dielectric. The mechanisms behind electromagnetic wave propagation in caves or tunnels are diverse, but can generally be attributed to reflection, diffraction, and scattering. Because of the multiple reflections from rough walls, the electromagnetic waves travel along different paths of varying lengths. The interactions between these waves cause multipath fading at any location, and the strengths of the waves decrease as the distance
Davis, Edward D.
2004-09-01
Semiclassical transformation theory implies an integral representation for stationary-state wave functions {psi}{sub m}(q) in terms of angle-action variables ({theta},J). It is a particular solution of Schroedinger's time-independent equation when terms of order ({Dirac_h}/2{pi}){sup 2} and higher are omitted, but the preexponential factor A(q,{theta}) in the integrand of this integral representation does not possess the correct dependence on q. The origin of the problem is identified: the standard unitarity condition invoked in semiclassical transformation theory does not fix adequately in A(q,{theta}) a factor which is a function of the action J written in terms of q and {theta}. A prescription for an improved choice of this factor, based on successfully reproducing the leading behavior of wave functions in the vicinity of potential minima, is outlined. Exact evaluation of the modified integral representation via the residue theorem is possible. It yields wave functions which are not, in general, orthogonal. However, closed-form results obtained after Gram-Schmidt orthogonalization bear a striking resemblance to the exact analytical expressions for the stationary-state wave functions of the various potential models considered (namely, a Poeschl-Teller oscillator and the Morse oscillator)
Electromagnetic wave emitting products and "Kikoh" potentiate human leukocyte functions.
Niwa, Y; Iizawa, O; Ishimoto, K; Jiang, X; Kanoh, T
1993-09-01
Tourmaline (electric stone, a type of granite stone), common granite stone, ceramic disks, hot spring water and human palmar energy (called "Kikoh" in Japan and China), all which emit electromagnetic radiation in the far infrared region (wavelength 4-14 microns). These materials were thus examined for effects on human leukocyte activity and on lipid peroxidation of unsaturated fatty acids. It was revealed that these materials significantly increased intracellular calcium ion concentration, phagocytosis, and generation of reactive oxygen species in neutrophils, and the blastogenetic response of lymphocytes to mitogens. Chemotactic activity by neutrophils was also enhanced by exposure to tourmaline and the palm of "Kikohshi" i.e., a person who heals professionally by the laying on of hands. Despite the increase in reactive oxygen species generated by neutrophils, lipid peroxidation from unsaturated fatty acid was markedly inhibited by these four materials. The results suggest that materials emitting electromagnetic radiation in the far infrared range, which are widely used in Japan for cosmetic, therapeutic, and preservative purposes, appear capable of potentiating leukocyte functions without promoting oxidative injury. PMID:8406976
NASA Astrophysics Data System (ADS)
Kim, G.; Shin, J.; Chi, H. C.; Sheen, D.; Park, J.; Cho, C.
2011-12-01
The crustal structure around the Korean Peninsula was investigated by analyzing the Rayleigh waves generated from the 2nd North Korea underground nuclear explosion on May 25, 2009. Group velocity dispersion curves were measured from vertical component waveforms of 20 broadband stations in the range of 194 to 1183 km from the test site. The measured dispersion curves were inverted to get shear-wave velocity models for depths from 0 to 50 km. The dispersion curves and the velocity models clearly show lateral variations in the crustal structure, which could be more clearly classified into the North Korea-Northeast China group, the Western Margin of the East Sea group, and the Japan Basin group. For each group, an averaged dispersion curve and an averaged velocity model were measured. The averaged shear-wave velocity model of the North Korea-Northeast China group shows that the mean shear-wave velocity of the Moho discontinuity, which is known to be located at approximately 35 km, is 4.37 km/s with a standard deviation of 0.15 km/s. The averaged shear-wave velocity model of the Japan Basin group shows a mean shear-wave velocity of 4.26 km/s with a standard deviation of 0.14 km/s in the layer between 16 and 22 km. The averaged shear-wave velocity model of the Western Margin of the East Sea group shows characteristics of a transition zone between the North Korea-Northeast China group, which represents continental crust, and the Japan Basin group, which represents oceanic crust. The mean shear-wave velocity in the layer between 16 and 22 km is 4.12 km/s with a standard deviation of 0.05 km/s.
Thermal-wave fields in solid wedges using the Green function method: Theory and experiment
NASA Astrophysics Data System (ADS)
Tai, Rui; Zhang, Jie; Wang, Chinhua; Mandelis, Andreas
2013-04-01
In this work, we establish a theoretical model for a cylindrical rod of radius R with opening angle θ illuminated by a modulated incident beam. The model uses the Green function method in cylindrical coordinates. An analytical expression for the Green function and thermal-wave field in such a solid is presented. The theory is validated in the limit of reducing the arbitrary wedge geometrical structure to simpler geometries. For acute angle wedges, it is shown that the thermal-wave field near the edge exhibits confinement behavior and increased amplitude compared to a flat (reference) solid with θ = π. For obtuse angle wedges, it is shown that the opposite is true and relaxation of confinement occurs leading to lower amplitude thermal-wave fields. The theory provides a basis for quantitative thermophysical characterization of wedge-shaped objects and it is tested using an AISI 304 steel wedge and photothermal radiometry detection.
Asymmetric radiation of seismic waves from an atoll: nuclear tests in French Polynesia
Weber, Michael; Wicks, Charles W., Jr.; Krüger, Frank; Jahnke, Gunnar; Schlittenhardt, Jörg
1998-01-01
Seismic records of nuclear tests detonated in the Mururoa Atoll in French Polynesia show large unpredicted arrivals 2.2 and 4.5 seconds (X1 and X2) after the P-wave at the Australian Warramunga Array. These arrivals are not observed at the Canadian Yellowknife Array. X1 and X2 are also absent on Warramunga Array recordings of tests carried out at the Fangataufa Atoll situated 40 km SSE of Mururoa. Array analysis shows that X1 and X2 are produced within the source area. The layered crustal structure of the atoll, significant local inhomogeneities, and focusing effects due to the elongated shape and the steep flanks of the Mururoa Atoll are most likely responsible for X1 and X2. The form of Mururoa (28 × 10 km) and its East-West orientation is due to its location on the Austral Fracture Zone (AFZ). The Fangataufa Atoll on the other hand is almost circular (10 km diameter) and is unaffected by the dynamics along the AFZ. Our observations demonstrate that complicated structures in the source area can significantly alter the wave field at teleseismic distances and produce a large magnitude (mb) bias. A better understanding of the exact cause of these unusual seismic observations will only become possible, if the coordinates of the tests and information on the detailed 3-D structure of the atolls are released.
The nuclear magnetic shielding as a function of internuclear separation
NASA Astrophysics Data System (ADS)
Jameson, Cynthia J.; de Dios, Angel C.
1993-02-01
Ab initio calculations of nuclear magnetic shielding surfaces for 23Na in the NaH molecule, 39Ar in ArNe, 21Ne in NeHe, and 39Ar in Ar...NaH are carried out over a wide range of internuclear separations, using a local origin method (LORG) which damps out the long-range errors due to incomplete basis sets. The R dependence of the intermolecular shielding in the attractive region of the potential in these systems and in Ar...Ar and Ar...Na+ are consistent with the long-range limiting forms associated with the shielding hyperpolarizability in conjunction with a mean square electric field approximation. The Cl and F shieldings over the range of nuclear displacements spanning the classical turning points of the ground vibrational states of ClF and F2 are found to be remarkably superposable upon scaling by the factors
NASA Astrophysics Data System (ADS)
Hansen, Mikkel Bo; Christiansen, Ove; Hättig, Christof
2009-10-01
Quadratic response functions are derived and implemented for a vibrational configuration interaction state. Combined electronic and vibrational quadratic response functions are derived using Born-Oppenheimer vibronic product wave functions. Computational tractable expressions are derived for determining the total quadratic response contribution as a sum of contributions involving both electronic and vibrational linear and quadratic response functions. In the general frequency-dependent case this includes a new and more troublesome type of electronic linear response function. Pilot calculations for the FH, H2O, CH2O, and pyrrole molecules demonstrate the importance of vibrational contributions for accurate comparison to experiment and that the vibrational contributions in some cases can be very large. The calculation of transition properties between vibrational states is combined with sum-over-states expressions for analysis purposes. On the basis of this some simple analysis methods are suggested. Also, a preliminary study of the effect of finite lifetimes on quadratic response functions is presented.
A search for the {Delta}{sup {minus}} wave-function component in light nuclei
Morris, C.L.; Zumbro, J.D.; Boudrie, R.L.
1996-10-01
We have studied the ({pi}{sup +}, {pi}{sup {+-}}p) reactions on {sup 3}He, {sup 4}He, {sup 6}Li, and {sup 7}Li at incident energy 500 MeV in quasi-free kinematics. A signature attributable to pre-existing {Delta} components of the ground state wave function is observed.
The Use of the Information Wave Function in a Drift Dependent Option Price: A Simple Example
Haven, Emmanuel
2009-03-10
This paper briefly describes how a drift-dependent option price is obtained, following the work of Tan. We briefly argue how the information wave function concept, which has now been used in various financial settings, can be used in this type of option price.
Seniority number in spin-adapted spaces and compactness of configuration interaction wave functions.
Alcoba, Diego R; Torre, Alicia; Lain, Luis; Massaccesi, Gustavo E; Oña, Ofelia B
2013-08-28
This work extends the concept of seniority number, which has been widely used for classifying N-electron Slater determinants, to wave functions of N electrons and spin S, as well as to N-electron spin-adapted Hilbert spaces. We propose a spin-free formulation of the seniority number operator and perform a study on the behavior of the expectation values of this operator under transformations of the molecular basis sets. This study leads to propose a quantitative evaluation for the convergence of the expansions of the wave functions in terms of Slater determinants. The non-invariant character of the seniority number operator expectation value of a wave function with respect to a unitary transformation of the molecular orbital basis set, allows us to search for a change of basis which minimizes that expectation value. The results found in the description of wave functions of selected atoms and molecules show that the expansions expressed in these bases exhibit a more rapid convergence than those formulated in the canonical molecular orbital bases and even in the natural orbital ones. PMID:24006970
Observations of the directional distribution of the wind energy input function over swell waves
NASA Astrophysics Data System (ADS)
Shabani, Behnam; Babanin, Alex V.; Baldock, Tom E.
2016-02-01
Field measurements of wind stress over shallow water swell traveling in different directions relative to the wind are presented. The directional distribution of the measured stresses is used to confirm the previously proposed but unverified directional distribution of the wind energy input function. The observed wind energy input function is found to follow a much narrower distribution (β∝cos3.6θ) than the Plant (1982) cosine distribution. The observation of negative stress angles at large wind-wave angles, however, indicates that the onset of negative wind shearing occurs at about θ≈ 50°, and supports the use of the Snyder et al. (1981) directional distribution. Taking into account the reverse momentum transfer from swell to the wind, Snyder's proposed parameterization is found to perform exceptionally well in explaining the observed narrow directional distribution of the wind energy input function, and predicting the wind drag coefficients. The empirical coefficient (ɛ) in Snyder's parameterization is hypothesised to be a function of the wave shape parameter, with ɛ value increasing as the wave shape changes between sinusoidal, sawtooth, and sharp-crested shoaling waves.
Three-Dimensional Visualization of Wave Functions for Rotating Molecule: Plot of Spherical Harmonics
ERIC Educational Resources Information Center
Nagaoka, Shin-ichi; Teramae, Hiroyuki; Nagashima, Umpei
2013-01-01
At an early stage of learning quantum chemistry, undergraduate students usually encounter the concepts of the particle in a box, the harmonic oscillator, and then the particle on a sphere. Rotational levels of a diatomic molecule can be well approximated by the energy levels of the particle on a sphere. Wave functions for the particle in a…
Alternative Form of the Hydrogenic Wave Functions for an Extended, Uniformly Charged Nucleus.
ERIC Educational Resources Information Center
Ley-Koo, E.; And Others
1980-01-01
Presented are forms of harmonic oscillator attraction and Coulomb wave functions which can be explicitly constructed and which lead to numerical results for the energy eigenvalues and eigenfunctions of the atomic system. The Schrodinger equation and its solution and specific cases of muonic atoms illustrating numerical calculations are included.…
Seniority number in spin-adapted spaces and compactness of configuration interaction wave functions
NASA Astrophysics Data System (ADS)
Alcoba, Diego R.; Torre, Alicia; Lain, Luis; Massaccesi, Gustavo E.; Oña, Ofelia B.
2013-08-01
This work extends the concept of seniority number, which has been widely used for classifying N-electron Slater determinants, to wave functions of N electrons and spin S, as well as to N-electron spin-adapted Hilbert spaces. We propose a spin-free formulation of the seniority number operator and perform a study on the behavior of the expectation values of this operator under transformations of the molecular basis sets. This study leads to propose a quantitative evaluation for the convergence of the expansions of the wave functions in terms of Slater determinants. The non-invariant character of the seniority number operator expectation value of a wave function with respect to a unitary transformation of the molecular orbital basis set, allows us to search for a change of basis which minimizes that expectation value. The results found in the description of wave functions of selected atoms and molecules show that the expansions expressed in these bases exhibit a more rapid convergence than those formulated in the canonical molecular orbital bases and even in the natural orbital ones.
Neznamov, V. P.; Silenko, A. J.
2009-12-15
The block diagonalization of the Hamiltonian is not sufficient for the transformation to the Foldy-Wouthuysen (FW) representation. The conditions enabling the transition from the Dirac representation to the FW one are formulated and proven. The connection between wave functions in the two representations is derived. The results obtained allow calculating expectation values of operators corresponding to main classical quantities.
Most probable wave function of a single free-moving particle
Budiyono, Agung
2009-10-15
We develop the most probable wave functions for a single free quantum particle given its momentum and energy by imposing its quantum probability density to maximize Shannon information entropy. We show that there is a class of solutions in which the quantum probability density is self-trapped with finite-size spatial support, uniformly moving, hence keeping its form unchanged.
Frequency-Domain Green's Functions for Radar Waves in Heterogeneous 2.5D Media
Green’s functions for radar waves propagating in heterogeneous media may be calculated in the frequency domain using a hybrid of two numerical methods. The model is defined in the Cartesian coordinate system, and its electromagnetic properties may vary in the x and z directions, ...
The incomplete plasma dispersion function: Properties and application to waves in bounded plasmas
Baalrud, S. D.
2013-01-15
The incomplete plasma dispersion function is a generalization of the plasma dispersion function in which the defining integral spans a semi-infinite, rather than infinite, domain. It is useful for describing the linear dielectric response and wave dispersion in non-Maxwellian plasmas when the distribution functions can be approximated as Maxwellian over finite, or semi-infinite, intervals in velocity phase-space. A ubiquitous example is the depleted Maxwellian electron distribution found near boundary sheaths or double layers, where the passing interval can be modeled as Maxwellian with a lower temperature than the trapped interval. The depleted Maxwellian is used as an example to demonstrate the utility of using the incomplete plasma dispersion function for calculating modifications to wave dispersion relations.
Structural and Functional Insight into Proliferating Cell Nuclear Antigen.
Park, So Young; Jeong, Mi Suk; Han, Chang Woo; Yu, Hak Sun; Jang, Se Bok
2016-04-28
Proliferating cell nuclear antigen (PCNA) is a critical eukaryotic replication accessory factor that supports DNA binding in DNA processing, such as DNA replication, repair, and recombination. PCNA consists of three toroidal-shaped monomers that encircle doublestranded DNA. The diverse functions of PCNA may be regulated by its interactions with partner proteins. Many of the PCNA partner proteins generally have a conserved PCNAinteracting peptide (PIP) motif, located at the N- or C- terminal region. The PIP motif forms a 310 helix that enters into the hydrophobic groove produced by an interdomain-connecting loop, a central loop, and a C-terminal tail in the PCNA. Post-translational modification of PCNA also plays a critical role in regulation of its function and binding partner proteins. Structural and biochemical studies of PCNA-protein will be useful in designing therapeutic agents, as well as estimating the outcome of anticancer drug development. This review summarizes the characterization of eukaryotic PCNA in relation to the protein structures, functions, and modifications, and interaction with proteins. PMID:26699741
McAleavey, Stephen A
2014-05-01
Shear wave induced phase encoding (SWIPE) imaging generates ultrasound backscatter images of tissue-like elastic materials by using traveling shear waves to encode the lateral position of the scatters in the phase of the received echo. In contrast to conventional ultrasound B-scan imaging, SWIPE offers the potential advantages of image formation without beam focusing or steering from a single transducer element, lateral resolution independent of aperture size, and the potential to achieve relatively high lateral resolution with low frequency ultrasound. Here a Fourier series description of the phase modulated echo signal is developed, demonstrating that echo harmonics at multiples of the shear wave frequency reveal target k-space data at identical multiples of the shear wavenumber. Modulation transfer functions of SWIPE imaging systems are calculated for maximum shear wave acceleration and maximum shear constraints, and compared with a conventionally focused aperture. The relative signal-to-noise ratio of the SWIPE method versus a conventionally focused aperture is found through these calculations. Reconstructions of wire targets in a gelatin phantom using 1 and 3.5 MHz ultrasound and a cylindrical shear wave source are presented, generated from the fundamental and second harmonic of the shear wave modulation frequency, demonstrating weak dependence of lateral resolution with ultrasound frequency. PMID:24815265
McAleavey, Stephen A.
2014-01-01
Shear wave induced phase encoding (SWIPE) imaging generates ultrasound backscatter images of tissue-like elastic materials by using traveling shear waves to encode the lateral position of the scatters in the phase of the received echo. In contrast to conventional ultrasound B-scan imaging, SWIPE offers the potential advantages of image formation without beam focusing or steering from a single transducer element, lateral resolution independent of aperture size, and the potential to achieve relatively high lateral resolution with low frequency ultrasound. Here a Fourier series description of the phase modulated echo signal is developed, demonstrating that echo harmonics at multiples of the shear wave frequency reveal target k-space data at identical multiples of the shear wavenumber. Modulation transfer functions of SWIPE imaging systems are calculated for maximum shear wave acceleration and maximum shear constraints, and compared with a conventionally focused aperture. The relative signal-to-noise ratio of the SWIPE method versus a conventionally focused aperture is found through these calculations. Reconstructions of wire targets in a gelatin phantom using 1 and 3.5 MHz ultrasound and a cylindrical shear wave source are presented, generated from the fundamental and second harmonic of the shear wave modulation frequency, demonstrating weak dependence of lateral resolution with ultrasound frequency. PMID:24815265
Modified Dihadron Fragmentation Functions in Hot and Nuclear Matter
Majumder, A.; Wang Enke; Wang Xinnian
2007-10-12
Medium modification of dihadron fragmentation functions due to gluon bremsstrahlung induced by multiple partonic scattering is studied in both deep-inelastic scattering (DIS) off large nuclei and high-energy heavy-ion collisions within the same framework of twist expansion. The modification for dihadrons is found to closely follow that for single hadrons, leading to a weak nuclear suppression of their ratios in DIS experiments. A mild enhancement of the near-side correlation of two high transverse momentum hadrons with increasing centrality is found in heavy-ion collisions due to trigger bias and the rise in parton energy loss with centrality. Successful comparisons between theory and experiment for multihadron observables in both confining and deconfined media offer comprehensive evidence for partonic energy loss as the mechanism of jet modification in dense matter.
Probability Distribution Functions of freak-waves: nonlinear vs linear model
NASA Astrophysics Data System (ADS)
Kachulin, Dmitriy; Dyachenko, Alexander; Zakharov, Vladimir
2015-04-01
No doubts that estimation of probability of freak-wave appearing at the surface of ocean has practical meaning. Among different mechanisms of this phenomenon linear dispersion and modulational instability are generally recognized. For linear equation of water waves Probability Distribution Functions (PDF) can be calculated analytically and it is nothing but normal Gaussian distribution for surface elevation. Or it is Rayleigh distribution for absolute values of elevations. For nonlinear waves one can expect something different. In this report we consider and compare these two mechanism for various levels of nonlinearity. We present results of numerical experiments on calculation of Probability Distribution Functions for surface elevations of waters waves both for nonlinear and linear models. Both model demonstrates Rayleigh distribution of surface elevations. However dispersion of PDF for nonlinear case is much larger than for linear case. This work was supported by the Grant "Wave turbulence: theory, numerical simulation, experiment" #14-22-00174 of Russian Science Foundation. Numerical simulation was performed on the Informational Computational Center of the Novosibirsk State University.
NASA Astrophysics Data System (ADS)
Hedayatrasa, Saeid; Bui, Tinh Quoc; Zhang, Chuanzeng; Lim, Chee Wah
2014-02-01
Numerical modeling of the Lamb wave propagation in functionally graded materials (FGMs) by a two-dimensional time-domain spectral finite element method (SpFEM) is presented. The high-order Chebyshev polynomials as approximation functions are used in the present formulation, which provides the capability to take into account the through thickness variation of the material properties. The efficiency and accuracy of the present model with one and two layers of 5th order spectral elements in modeling wave propagation in FGM plates are analyzed. Different excitation frequencies in a wide range of 28-350 kHz are investigated, and the dispersion properties obtained by the present model are verified by reference results. The through thickness wave structure of two principal Lamb modes are extracted and analyzed by the symmetry and relative amplitude of the vertical and horizontal oscillations. The differences with respect to Lamb modes generated in homogeneous plates are explained. Zero-crossing and wavelet signal processing-spectrum decomposition procedures are implemented to obtain phase and group velocities and their dispersion properties. So it is attested how this approach can be practically employed for simulation, calibration and optimization of Lamb wave based nondestructive evaluation techniques for the FGMs. The capability of modeling stress wave propagation through the thickness of an FGM specimen subjected to impact load is also investigated, which shows that the present method is highly accurate as compared with other existing reference data.
Examples of Heun and Mathieu functions as solutions of wave equations in curved spaces
NASA Astrophysics Data System (ADS)
Birkandan, T.; Horta, M.
We give examples of where the Heun function exists as solutions of wave equations encountered in general relativity. While the Dirac equation written in the background of Nutku helicoid metric yields Mathieu functions as its solutions in four spacetime dimensions, the trivial generalization to five dimensions results in the double confluent Heun function. We reduce this solution to the Mathieu function with some transformations. We must apply Atiyah-Patodi-Singer spectral boundary conditions to this system since the metric has a singularity at the origin.
NASA Astrophysics Data System (ADS)
Goldstein, Sheldon; Lebowitz, Joel L.; Mastrodonato, Christian; Tumulka, Roderich; Zanghì, Nino
2016-03-01
A quantum system (with Hilbert space {H}1) entangled with its environment (with Hilbert space {H}2) is usually not attributed to a wave function but only to a reduced density matrix {ρ1}. Nevertheless, there is a precise way of attributing to it a random wave function {ψ1}, called its conditional wave function, whose probability distribution {μ1} depends on the entangled wave function {ψ in H1 ⊗ H2} in the Hilbert space of system and environment together. It also depends on a choice of orthonormal basis of H2 but in relevant cases, as we show, not very much. We prove several universality (or typicality) results about {μ1}, e.g., that if the environment is sufficiently large then for every orthonormal basis of H2, most entangled states {ψ} with given reduced density matrix {ρ1} are such that {μ1} is close to one of the so-called GAP (Gaussian adjusted projected) measures, {GAP(ρ1)}. We also show that, for most entangled states {ψ} from a microcanonical subspace (spanned by the eigenvectors of the Hamiltonian with energies in a narrow interval {[E, E+ δ E]}) and most orthonormal bases of H2, {μ1} is close to {GAP({tr}2 ρ_{mc})} with {ρ_{mc}} the normalized projection to the microcanonical subspace. In particular, if the coupling between the system and the environment is weak, then {μ1} is close to {GAP(ρ_β)} with {ρ_β} the canonical density matrix on H1 at inverse temperature {β=β(E)}. This provides the mathematical justification of our claim in Goldstein et al. (J Stat Phys 125: 1193-1221, 2006) that GAP measures describe the thermal equilibrium distribution of the wave function.
Horizon wave function for single localized particles: GUP and quantum black-hole decay
NASA Astrophysics Data System (ADS)
Casadio, Roberto; Scardigli, Fabio
2014-01-01
A localized particle in Quantum Mechanics is described by a wave packet in position space, regardless of its energy. However, from the point of view of General Relativity, if the particle's energy density exceeds a certain threshold, it should be a black hole. To combine these two pictures, we introduce a horizon wave function determined by the particle wave function in position space, which eventually yields the probability that the particle is a black hole. The existence of a minimum mass for black holes naturally follows, albeit not in the form of a sharp value around the Planck scale, but rather like a vanishing probability that a particle much lighter than the Planck mass may be a black hole. We also show that our construction entails an effective generalized uncertainty principle (GUP), simply obtained by adding the uncertainties coming from the two wave functions associated with a particle. Finally, the decay of microscopic (quantum) black holes is also described in agreement with what the GUP predicts.
Sykes, Lynn R.; Cifuentes, Inés L.
1984-01-01
Magnitudes of the larger Soviet underground nuclear weapons tests from the start of the Threshold Test Ban Treaty in 1976 through 1982 are determined for short- and long-period seismic waves. Yields are calculated from the surface wave magnitude for those explosions at the eastern Kazakh test site that triggered a small-to-negligible component of tectonic stress and are used to calibrate body wave magnitude-yield relationship that can be used to determine the sizes of other explosions at that test site. The results confirm that a large bias, related to differential attenuation of P waves, exists between Nevada and Central Asia. The yields of the seven largest Soviet explosions are nearly identical and are close to 150 kilotons, the limit set by the Threshold Treaty. PMID:16593440
Tang, Jau
1996-02-01
As an alternative to better physical explanations of the mechanisms of quantum interference and the origins of uncertainty broadening, a linear hopping model is proposed with ``color-varying`` dynamics to reflect fast exchange between time-reversed states. Intricate relations between this model, particle-wave dualism, and relativity are discussed. The wave function is shown to possess dual characteristics of a stable, localized ``soliton-like`` de Broglie wavelet and a delocalized, interfering Schroedinger carrier wave function.
Nuclear receptors CAR and PXR: Molecular, functional, and biomedical aspects.
di Masi, Alessandra; De Marinis, Elisabetta; Ascenzi, Paolo; Marino, Maria
2009-10-01
Nuclear receptors (NRs) are ligand-activated transcription factors sharing a common evolutionary history and having similar sequence features at the protein level. Selective ligand(s) for some NRs is not known, therefore these NRs have been named "orphan receptors". Whenever ligands have been recognized for any of the orphan receptor, it has been categorized and grouped as "adopted" orphan receptor. This group includes the constitutive androstane receptor (CAR) and the pregnane X receptor (PXR). They function as sensors of toxic byproducts derived from endogenous metabolites and of exogenous chemicals, in order to enhance their elimination. This unique function of CAR and PXR sets them apart from the steroid hormone receptors. The broad response profile has established that CAR and PXR are xenobiotic sensors that coordinately regulate xenobiotic clearance in the liver and intestine via induction of genes involved in drug and xenobiotic metabolism. In the past few years, research has revealed new and mostly unsuspected roles for CAR and PXR in modulating hormone, lipid, and energy homeostasis as well as cancer and liver steatosis. The purpose of this review is to highlight the structural and molecular bases of CAR and PXR impact on human health, providing information on mechanisms through which diet, chemical exposure, and environment ultimately impact health and disease. PMID:19427329
Dust heating by Alfvén waves using non-Maxwellian distribution function
Zubia, K.; Shah, H. A.; Yoon, P. H.
2015-08-15
Quasilinear theory is employed in order to evaluate the resonant heating rate by Alfvén waves, of multiple species dust particles in a hot, collisionless, and magnetized plasma, with the underlying assumption that the dust velocity distribution function can be modeled by a generalized (r, q) distribution function. The kinetic linear dispersion relation for the electromagnetic dust cyclotron Alfvén waves is derived, and the dependence of the heating rate on the magnetic field, mass, and density of the dust species is subsequently investigated. The heating rate and its dependence on the spectral indices r and q of the distribution function are also investigated. It is found that the heating is sensitive to negative value of spectral index r.
Non-dipolar gauge links for transverse-momentum-dependent pion wave functions
NASA Astrophysics Data System (ADS)
Wang, Yu-Ming
2016-03-01
I discuss the factorization-compatible definitions of transverse-momentumdependent (TMD) pion wave functions which are fundamental theory inputs entering QCD factorization formulae for many hard exclusive processes. I will first demonstrate that the soft subtraction factor introduced to remove both rapidity and pinch singularities can be greatly reduced by making the maximal use of the freedom to construct the Wilson-line paths when defining the TMD wave functions. I will then turn to show that the newly proposed TMD definition with non-dipolarWilson lines is equivalent to the one with dipolar gauge links and with a complicated soft function, to all orders of the perturbative expansion in the strong coupling, as far as the infrared behavior is concerned.
Frequency-domain Green's functions for radar waves in heterogeneous 2.5D media
Ellefsen, K.J.; Croize, D.; Mazzella, A.T.; McKenna, J.R.
2009-01-01
Green's functions for radar waves propagating in heterogeneous 2.5D media might be calculated in the frequency domain using a hybrid method. The model is defined in the Cartesian coordinate system, and its electromagnetic properties might vary in the x- and z-directions, but not in the y-direction. Wave propagation in the x- and z-directions is simulated with the finite-difference method, and wave propagation in the y-direction is simulated with an analytic function. The absorbing boundaries on the finite-difference grid are perfectly matched layers that have been modified to make them compatible with the hybrid method. The accuracy of these numerical Greens functions is assessed by comparing them with independently calculated Green's functions. For a homogeneous model, the magnitude errors range from -4.16% through 0.44%, and the phase errors range from -0.06% through 4.86%. For a layered model, the magnitude errors range from -2.60% through 2.06%, and the phase errors range from -0.49% through 2.73%. These numerical Green's functions might be used for forward modeling and full waveform inversion. ?? 2009 Society of Exploration Geophysicists. All rights reserved.
Global Propagation of Gravity Waves Generated with the Whole Atmosphere Transfer Function Model
NASA Astrophysics Data System (ADS)
Mayr, H. G.; Talaat, E. R.; Wolven, B. C.
2012-12-01
Gravity waves are ubiquitous phenomena in the Earth's atmosphere, accounting for a significant fraction of its observed variability. These waves, with periods ranging from minutes to hours, are thought to be a major means for exchange of momentum and energy between atmospheric regions. The Transfer Function Model (TFM) describes acoustic gravity waves (AGW) that propagate across the globe in a dissipative static background atmosphere extending from the ground to 700 km. The model is limited to waves with periods << 12 hr where the Coriolis force is not important. Formulated in terms of zonal vector spherical harmonics and oscillation frequencies, the linearized equations of energy, mass, and momentum conservation are solved to generate the transfer function (TF) for a chosen height distribution of the excitation source. The model accounts for momentum exchange between atmospheric species (He, O, N2, O2, Ar), which affects significantly the wave amplitudes and phases of thermospheric temperature, densities, and wind fields. Covering a broad range of frequencies and spherical harmonic wave numbers (wavelengths), without limitations, the assembled TF captures the physics that controls the propagation of AGW, and the computational effort is considerable. For a chosen horizontal geometry and impulsive time dependence of the source, however, the global wave response is then obtained in short order. The model is computationally efficient and well suited to serve as an experimental and educational tool for simulating propagating wave patterns on the globe. The model is also semi-analytical and therefore well suited to explore the different wave modes that can be generated under varying dynamical conditions. The TFM has been applied to simulate the AGW, which are generated in the auroral region of the thermosphere by joule heating and momentum coupling due to solar wind induced electric fields [e.g., Mayr et al., Space Science Reviews, 1990]. The auroral source generates
Multi-spectral Metasurface for Different Functional Control of Reflection Waves.
Huang, Cheng; Pan, Wenbo; Ma, Xiaoliang; Luo, Xiangang
2016-01-01
Metasurface have recently generated much interest due to its strong manipulation of electromagnetic wave and its easy fabrication compared to bulky metamaterial. Here, we propose the design of a multi-spectral metasurface that can achieve beam deflection and broadband diffusion simultaneously at two different frequency bands. The metasurface is composed of two-layered metallic patterns backed by a metallic ground plane. The top-layer metasurface utilizes the cross-line structures with two different dimensions for producing 0 and π reflection phase response, while the bottom-layer metasurface is realized by a topological morphing of the I-shaped patterns for creating the gradient phase distribution. The whole metasurface is demonstrated to independently control the reflected waves to realize different functions at two bands when illuminated by a normal linear-polarized wave. Both simulation and experimental results show that the beam deflection is achieved at K-band with broadband diffusion at X-Ku band. PMID:27001206
Multi-spectral Metasurface for Different Functional Control of Reflection Waves
NASA Astrophysics Data System (ADS)
Huang, Cheng; Pan, Wenbo; Ma, Xiaoliang; Luo, Xiangang
2016-03-01
Metasurface have recently generated much interest due to its strong manipulation of electromagnetic wave and its easy fabrication compared to bulky metamaterial. Here, we propose the design of a multi-spectral metasurface that can achieve beam deflection and broadband diffusion simultaneously at two different frequency bands. The metasurface is composed of two-layered metallic patterns backed by a metallic ground plane. The top-layer metasurface utilizes the cross-line structures with two different dimensions for producing 0 and π reflection phase response, while the bottom-layer metasurface is realized by a topological morphing of the I-shaped patterns for creating the gradient phase distribution. The whole metasurface is demonstrated to independently control the reflected waves to realize different functions at two bands when illuminated by a normal linear-polarized wave. Both simulation and experimental results show that the beam deflection is achieved at K-band with broadband diffusion at X-Ku band.
A Proton-Cyclotron Wave Storm Generated by Unstable Proton Distribution Functions in the Solar Wind
NASA Technical Reports Server (NTRS)
Wicks, R. T.; Alexander, R. L.; Stevens, M.; Wilson, L. B., III; Moya, P. S.; Vinas, A.; Jian, L. K.; Roberts, D. A.; O’Modhrain, S.; Gilbert, J. A.; Zurbuchen, T. H.
2016-01-01
We use audification of 0.092 seconds cadence magnetometer data from the Wind spacecraft to identify waves with amplitudes greater than 0.1 nanoteslas near the ion gyrofrequency (approximately 0.1 hertz) with duration longer than 1 hour during 2008. We present one of the most common types of event for a case study and find it to be a proton-cyclotron wave storm, coinciding with highly radial magnetic field and a suprathermal proton beam close in density to the core distribution itself. Using linear Vlasov analysis, we conclude that the long-duration, large-amplitude waves are generated by the instability of the proton distribution function. The origin of the beam is unknown, but the radial field period is found in the trailing edge of a fast solar wind stream and resembles other events thought to be caused by magnetic field footpoint motion or interchange reconnection between coronal holes and closed field lines in the corona.
Multi-spectral Metasurface for Different Functional Control of Reflection Waves
Huang, Cheng; Pan, Wenbo; Ma, Xiaoliang; Luo, Xiangang
2016-01-01
Metasurface have recently generated much interest due to its strong manipulation of electromagnetic wave and its easy fabrication compared to bulky metamaterial. Here, we propose the design of a multi-spectral metasurface that can achieve beam deflection and broadband diffusion simultaneously at two different frequency bands. The metasurface is composed of two-layered metallic patterns backed by a metallic ground plane. The top-layer metasurface utilizes the cross-line structures with two different dimensions for producing 0 and π reflection phase response, while the bottom-layer metasurface is realized by a topological morphing of the I-shaped patterns for creating the gradient phase distribution. The whole metasurface is demonstrated to independently control the reflected waves to realize different functions at two bands when illuminated by a normal linear-polarized wave. Both simulation and experimental results show that the beam deflection is achieved at K-band with broadband diffusion at X-Ku band. PMID:27001206
Mapped orthogonal functions method applied to acoustic waves-based devices
NASA Astrophysics Data System (ADS)
Lefebvre, J. E.; Yu, J. G.; Ratolojanahary, F. E.; Elmaimouni, L.; Xu, W. J.; Gryba, T.
2016-06-01
This work presents the modelling of acoustic wave-based devices of various geometries through a mapped orthogonal functions method. A specificity of the method, namely the automatic incorporation of boundary conditions into equations of motion through position-dependent physical constants, is presented in detail. Formulations are given for two classes of problems: (i) problems with guided mode propagation and (ii) problems with stationary waves. The method's interest is demonstrated by several examples, a seven-layered plate, a 2D rectangular resonator and a 3D cylindrical resonator, showing how it is easy to obtain either dispersion curves and field profiles for devices with guided mode propagation or electrical response for devices with stationary waves. Extensions and possible further developments are also given.
A Proton-cyclotron Wave Storm Generated by Unstable Proton Distribution Functions in the Solar Wind
NASA Astrophysics Data System (ADS)
Wicks, R. T.; Alexander, R. L.; Stevens, M.; Wilson, L. B., III; Moya, P. S.; Viñas, A.; Jian, L. K.; Roberts, D. A.; O'Modhrain, S.; Gilbert, J. A.; Zurbuchen, T. H.
2016-03-01
We use audification of 0.092 s cadence magnetometer data from the Wind spacecraft to identify waves with amplitudes \\gt 0.1 nT near the ion gyrofrequency (˜0.1 Hz) with duration longer than 1 hr during 2008. We present one of the most common types of event for a case study and find it to be a proton-cyclotron wave storm, coinciding with highly radial magnetic field and a suprathermal proton beam close in density to the core distribution itself. Using linear Vlasov analysis, we conclude that the long-duration, large-amplitude waves are generated by the instability of the proton distribution function. The origin of the beam is unknown, but the radial field period is found in the trailing edge of a fast solar wind stream and resembles other events thought to be caused by magnetic field footpoint motion or interchange reconnection between coronal holes and closed field lines in the corona.
Bumps of the wave structure function in non-Kolmogorov turbulence
NASA Astrophysics Data System (ADS)
Qiao, Chunhong; Lu, Lu; Zhang, Pengfei; Wang, Haitao; Huang, Honghua; Fan, Chengyu
2015-10-01
The analytical expressions for wave structure function of plane and spherical waves are derived both in the viscous dissipation and inertial range. Due to previously research, there is a discrepancy between theoretical results and the experimental datum in viscous dissipation range. In this paper, only considering the inertial range, taking plane waves for example, we give a comparison of results of WSF calculated by the analytical formula obtained in this paper and the numerical calculations of the definition at the fixed parameter (i.e., the generalized exponent α), it can be seen that the two results are in agreement with each other exactly. Based on non-Kolmogorov power spectrum, new characteristics for wave structure function (WSF) have been found for plane and spherical wave models when the different ratio of inner scale l0 and outer scale of turbulence L0 is obtained. In outer scale assumed finite case (i.e., L0 =1m), WSF obtains the maximum when α approximates to 3.3 both for plane and spherical wave models. In outer scale assumed infinite case (i.e., L0 = ∞), the WSF can be sorted into three parts, including two rapid-rising regions (i.e., 3.0 < α < 3.3 and 3.8 < α < 4.0 ) and one gently rising region (i.e., 3.3 < α < 3.8 ).Further, the changes of scaled WSF versus the ratio of separation distance and inner scale ( p/ l0 ) are investigated under mentioned above conditions for two models. In L0 = 1m case, both for plane and spherical waves, the value of α determines the bump position of WSF. In L0 = ∞ case, the bump of scaled WSF disappears when the generalized exponent has large values. The changings of scaled WSF monotonically increase as α increased when the generalized exponent is larger than11/3 for two models. Besides, the properties of spherical waves are similar to plane waves, except which the values of WSF and the scaled WSF are smaller than plane ones.
Assessments of Arterial Stiffness and Endothelial Function Using Pulse Wave Analysis
Stoner, Lee; Young, Joanna M.; Fryer, Simon
2012-01-01
Conventionally, the assessments of endothelial function and arterial stiffness require different sets of equipment, making the inclusion of both tests impractical for clinical and epidemiological studies. Pulse wave analysis (PWA) provides useful information regarding the mechanical properties of the arterial tree and can also be used to assess endothelial function. PWA is a simple, valid, reliable, and inexpensive technique, offering great clinical and epidemiological potential. The current paper will outline how to measure arterial stiffness and endothelial function using this technique and include discussion of validity and reliability. PMID:22666595
NASA Astrophysics Data System (ADS)
Peng, Liang-You; Gong, Qihuang
2010-12-01
The accurate computations of hydrogenic continuum wave functions are very important in many branches of physics such as electron-atom collisions, cold atom physics, and atomic ionization in strong laser fields, etc. Although there already exist various algorithms and codes, most of them are only reliable in a certain ranges of parameters. In some practical applications, accurate continuum wave functions need to be calculated at extremely low energies, large radial distances and/or large angular momentum number. Here we provide such a code, which can generate accurate hydrogenic continuum wave functions and corresponding Coulomb phase shifts at a wide range of parameters. Without any essential restrict to angular momentum number, the present code is able to give reliable results at the electron energy range [10,10] eV for radial distances of [10,10] a.u. We also find the present code is very efficient, which should find numerous applications in many fields such as strong field physics. Program summaryProgram title: HContinuumGautchi Catalogue identifier: AEHD_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEHD_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 1233 No. of bytes in distributed program, including test data, etc.: 7405 Distribution format: tar.gz Programming language: Fortran90 in fixed format Computer: AMD Processors Operating system: Linux RAM: 20 MBytes Classification: 2.7, 4.5 Nature of problem: The accurate computation of atomic continuum wave functions is very important in many research fields such as strong field physics and cold atom physics. Although there have already existed various algorithms and codes, most of them can only be applicable and reliable in a certain range of parameters. We present here an accurate FORTRAN program for
Kinetic Alfven wave in the presence of kappa distribution function in plasma sheet boundary layer
Shrivastava, G. Ahirwar, G.; Shrivastava, J.
2015-07-31
The particle aspect approach is adopted to investigate the trajectories of charged particles in the electromagnetic field of kinetic Alfven wave. Expressions are found for the dispersion relation, damping/growth rate and associated currents in the presence of kappa distribution function. Kinetic effect of electrons and ions are included to study kinetic Alfven wave because both are important in the transition region. It is found that the ratio β of electron thermal energy density to magnetic field energy density and the ratio of ion to electron thermal temperature (T{sub i}/T{sub e}), and kappa distribution function affect the dispersion relation, damping/growth rate and associated currents in both cases(warm and cold electron limit).The treatment of kinetic Alfven wave instability is based on assumption that the plasma consist of resonant and non resonant particles. The resonant particles participate in an energy exchange process, whereas the non resonant particles support the oscillatory motion of the wave.
An Evans-function approach to spectral stability of internal solitary waves in stratified fluids
NASA Astrophysics Data System (ADS)
Klaiber, Andreas
2015-11-01
Frequently encountered in nature, internal solitary waves in stratified fluids have been investigated experimentally, theoretically, and numerically. Mathematically, these waves are exact solutions of the incompressible 2D Euler equations. Contrasting with a rich existence theory and the development of methods for their computation, their stability analysis has hardly received attention at a rigorous mathematical level. This paper proposes a new approach to the investigation of stability of internal solitary waves in a continuously stratified fluid and carries out the following four steps of this approach: (I) to formulate the eigenvalue problem as an infinite-dimensional spatial-dynamical system, (II) to introduce finite-dimensional truncations of the spatial-dynamics description, (III) to demonstrate that each truncation, of any order, permits a well-defined Evans function, (IV) to prove absence of small zeros of the Evans function in the small-amplitude limit. The latter notably implies the low-frequency spectral stability of small-amplitude waves to arbitrarily high truncation order.
Sensory Function: Insights From Wave 2 of the National Social Life, Health, and Aging Project
Kern, David W.; Wroblewski, Kristen E.; Chen, Rachel C.; Schumm, L. Philip; McClintock, Martha K.
2014-01-01
Objectives. Sensory function, a critical component of quality of life, generally declines with age and influences health, physical activity, and social function. Sensory measures collected in Wave 2 of the National Social Life, Health, and Aging Project (NSHAP) survey focused on the personal impact of sensory function in the home environment and included: subjective assessment of vision, hearing, and touch, information on relevant home conditions and social sequelae as well as an improved objective assessment of odor detection. Method. Summary data were generated for each sensory category, stratified by age (62–90 years of age) and gender, with a focus on function in the home setting and the social consequences of sensory decrements in each modality. Results. Among both men and women, older age was associated with self-reported impairment of vision, hearing, and pleasantness of light touch. Compared with women, men reported significantly worse hearing and found light touch less appealing. There were no gender differences for vision. Overall, hearing loss seemed to have a greater impact on social function than did visual impairment. Discussion. Sensory function declines across age groups, with notable gender differences for hearing and light touch. Further analysis of sensory measures from NSHAP Wave 2 may provide important information on how sensory declines are related to health, social function, quality of life, morbidity, and mortality in this nationally representative sample of older adults. PMID:25360015
State-of-the-art of beyond mean field theories with nuclear density functionals
NASA Astrophysics Data System (ADS)
Egido, J. Luis
2016-07-01
We present an overview of different beyond mean field theories (BMFTs) based on the generator coordinate method (GCM) and the recovery of symmetries used in many body nuclear physics with effective forces. In a first step a short reminder of the Hartree–Fock–Bogoliubov (HFB) theory is given. A general discussion of the shortcomings of any mean field approximation (MFA), stemming either from the lack of the elementary symmetries (like particle number and angular momentum) or the absence of fluctuations around the mean values, is presented. The recovery of the symmetries spontaneously broken in the HFB approach, in particular the angular momentum, is necessary, among others, to describe excited states and transitions. Particle number projection is also needed to guarantee the right number of protons and neutrons. Furthermore a projection before the variation prevents the pairing collapse in the weak pairing regime. A whole chapter is devoted to illustrate with examples the convenience of recovering symmetries and the differences between the projection before and after the variation. The lack of fluctuations around the average values of the MFA is a big shortcoming inherent to this approach. To build in correlations in BMFT one selects the relevant degrees of freedom of the atomic nucleus. In the low energy part of the spectrum these are the quadrupole, octupole and the pairing vibrations as well as the single particle degrees of freedom. In the GCM the operators representing these degrees of freedom are used as coordinates to generate, by the constrained (projected) HFB theory, a collective subspace. The highly correlated GCM wave function is finally written as a linear combination of a projected basis of this space. The variation of the coefficients of the linear combination leads to the Hill–Wheeler equation. The flexibility of the GCM Ansatz allows to describe a whole palette of physical situations by conveniently choosing the generator coordinates. We
The Transfer Function Model (TFM) as a Tool for Simulating Gravity Wave Phenomena in the Mesosphere
NASA Astrophysics Data System (ADS)
Porter, H.; Mayr, H.; Moore, J.; Wilson, S.; Armaly, A.
2008-12-01
The Transfer Function Model (TFM) is semi-analytical and linear, and it is designed to describe the acoustic gravity waves (GW) propagating over the globe and from the ground to 600 km under the influence of vertical temperature variations. Wave interactions with the flow are not accounted for. With an expansion in terms of frequency-dependent spherical harmonics, the time consuming vertical integration of the conservation equations is reduced to computing the transfer function (TF). (The applied lower and upper boundary conditions assure that spurious wave reflections will not occur.) The TF describes the dynamical properties of the medium divorced from the complexities of the temporal and horizontal variations of the excitation source. Given the TF, the atmospheric response to a chosen source is then obtained in short order to simulate the GW propagating through the atmosphere over the globe. In the past, this model has been applied to study auroral processes, which produce distinct wave phenomena such as: (1) standing lamb modes that propagate horizontally in the viscous medium of the thermosphere, (2) waves generated in the auroral oval that experience geometric amplification propagating to the pole where constructive interference generates secondary waves that propagate equatorward, (3) ducted modes propagating through the middle atmosphere that leak back into the thermosphere, and (4) GWs reflected from the Earth's surface that reach the thermosphere in a narrow propagation cone. Well-defined spectral features characterize these wave modes in the TF to provide analytical understanding. We propose the TFM as a tool for simulating GW in the mesosphere and in particular the features observed in Polar Mesospheric Clouds (PMC). With present-day computers, it takes less than one hour to compute the TF, so that there is virtually no practical limitation on the source configurations that can be applied and tested in the lower atmosphere. And there is no limitation on
Simple model potential and model wave functions for (H-alkali)+ and (alkali-alkali)+ ions
NASA Astrophysics Data System (ADS)
Patil, S. H.; Tang, K. T.
2000-07-01
A simple model potential is proposed to describe the interaction of a valence electron with the alkali core, which incorporates the correct asymptotic behavior in terms of dipolar polarizabilities, and the short-range exchange effects in terms of a hard core adjusted to give the correct energy for the valence electron. Based on this potential, simple wave functions are developed to describe the (H-alkali)+ and (alkali-alkali)+ ions. These wave functions exhibit some important structures of the ions, and provide a universal description of the properties of all (H-alkali)+ and (alkali-alkali)+ ions, in particular, the equilibrium separations of the nuclei and the corresponding dissociation energies. They also allow us to calculate the dipolar polarizabilities of Li2+, Na2+, K2+, Rb2+, and Cs2+.
Dynamical Quantum Phase Transitions: Role of Topological Nodes in Wave Function Overlaps
NASA Astrophysics Data System (ADS)
Huang, Zhoushen; Balatsky, Alexander V.
2016-08-01
A sudden quantum quench of a Bloch band from one topological phase toward another has been shown to exhibit an intimate connection with the notion of a dynamical quantum phase transition (DQPT), where the returning probability of the quenched state to the initial state—i.e., the Loschmidt echo—vanishes at critical times {t*}. Analytical results to date are limited to two-band models, leaving the exact relation between topology and DQPT unclear. In this Letter, we show that, for a general multiband system, a robust DQPT relies on the existence of nodes (i.e., zeros) in the wave function overlap between the initial band and the postquench energy eigenstates. These nodes are topologically protected if the two participating wave functions have distinctive topological indices. We demonstrate these ideas in detail for both one and two spatial dimensions using a three-band generalized Hofstadter model. We also discuss possible experimental observations.
Dynamical Quantum Phase Transitions: Role of Topological Nodes in Wave Function Overlaps.
Huang, Zhoushen; Balatsky, Alexander V
2016-08-19
A sudden quantum quench of a Bloch band from one topological phase toward another has been shown to exhibit an intimate connection with the notion of a dynamical quantum phase transition (DQPT), where the returning probability of the quenched state to the initial state-i.e., the Loschmidt echo-vanishes at critical times {t^{*}}. Analytical results to date are limited to two-band models, leaving the exact relation between topology and DQPT unclear. In this Letter, we show that, for a general multiband system, a robust DQPT relies on the existence of nodes (i.e., zeros) in the wave function overlap between the initial band and the postquench energy eigenstates. These nodes are topologically protected if the two participating wave functions have distinctive topological indices. We demonstrate these ideas in detail for both one and two spatial dimensions using a three-band generalized Hofstadter model. We also discuss possible experimental observations. PMID:27588874
NASA Technical Reports Server (NTRS)
Weissman, D. E.; Johnson, J. W.
1984-01-01
The directional spectrum and the microwave modulation transfer function of ocean waves can be measured with the airborne two frequency scatterometer technique. Similar to tower based observations, the aircraft measurements of the Modulation Transfer Function (MTF) show that it is strongly affected by both wind speed and sea state. Also detected are small differences in the magnitudes of the MTF between downwind and upwind radar look directions, and variations with ocean wavenumber. The MTF inferred from the two frequency radar is larger than that measured using single frequency, wave orbital velocity techniques such as tower based radars or ROWS measurements from low altitude aircraft. Possible reasons for this are discussed. The ability to measure the ocean directional spectrum with the two frequency scatterometer, with supporting MTF data, is demonstrated.
Entropy and Exact Matrix-Product Representation of the Laughlin Wave Function
Iblisdir, S.; Latorre, J. I.; Orus, R.
2007-02-09
An analytical expression for the von Neumann entropy of the Laughlin wave function is obtained for any possible bipartition between the particles described by this wave function, for a filling fraction {nu}=1. Also, for a filling fraction {nu}=1/m, where m is an odd integer, an upper bound on this entropy is exhibited. These results yield a bound on the smallest possible size of the matrices for an exact representation of the Laughlin ansatz in terms of a matrix-product state. An analytical matrix-product state representation of this state is proposed in terms of representations of the Clifford algebra. For {nu}=1, this representation is shown to be asymptotically optimal in the limit of a large number of particles.
Entropy and exact matrix-product representation of the Laughlin wave function.
Iblisdir, S; Latorre, J I; Orús, R
2007-02-01
An analytical expression for the von Neumann entropy of the Laughlin wave function is obtained for any possible bipartition between the particles described by this wave function, for a filling fraction nu=1. Also, for a filling fraction nu=1/m, where m is an odd integer, an upper bound on this entropy is exhibited. These results yield a bound on the smallest possible size of the matrices for an exact representation of the Laughlin ansatz in terms of a matrix-product state. An analytical matrix-product state representation of this state is proposed in terms of representations of the Clifford algebra. For nu=1, this representation is shown to be asymptotically optimal in the limit of a large number of particles. PMID:17358918
Probing wave function collapse models with a classically driven mechanical oscillator
NASA Astrophysics Data System (ADS)
Ho, Melvyn; Lafont, Ambroise; Sangouard, Nicolas; Sekatski, Pavel
2016-03-01
We show that the interaction of a pulsed laser light with a mechanical oscillator through the radiation pressure results in an opto-mechanical entangled state in which the photon number is correlated with the oscillator position. Interestingly, the mechanical oscillator can be delocalized over a large range of positions when driven by an intense laser light. This provides a simple yet sensitive method to probe hypothetical post-quantum theories including an explicit wave function collapse model, like the Diosi & Penrose model. We propose an entanglement witness to reveal the quantum nature of this opto-mechanical state as well as an optical technique to record the decoherence of the mechanical oscillator. We also report on a detailed feasibility study giving the experimental challenges that need to be overcome in order to confirm or rule out predictions from explicit wave function collapse models.
Hadron wave functions as a probe of a two-color baryonic medium
NASA Astrophysics Data System (ADS)
Amato, Alessandro; Giudice, Pietro; Hands, Simon
2015-04-01
The properties of the ground state of two-color QCD at non-zero baryon chemical potential μ present an interesting problem in strongly interacting gauge theory; in particular the nature of the physically relevant degrees of freedom in the superfluid phase in the post-onset regime μ > m π /2 still needs clarification. In this study we present evidence for in-medium effects at high μ by studying the wave functions of mesonic and diquark states using orthodox lattice simulation techniques, made possible by the absence of a sign problem for the model with N f = 2. Our results show that beyond onset the spatial extent of hadrons decreases as μ grows, and that the wave function profiles are consistent with the existence of a dynamically gapped Fermi surface in this regime.
Velocity and attenuation of scalar and elastic waves in random media: a spectral function approach.
Calvet, Marie; Margerin, Ludovic
2012-03-01
This paper investigates the scattering of scalar and elastic waves in two-phase materials and single-mineral-cubic, hexagonal, orthorhombic-polycrystalline aggregates with randomly oriented grains. Based on the Dyson equation for the mean field, explicit expressions for the imaginary part of Green's function in the frequency-wavenumber domain (ω, p), also known as the spectral function, are derived. This approach allows the identification of propagating modes with their relative contribution, and the computation of both attenuation and phase velocity for each mode. The results should be valid from the Rayleigh (low-frequency) to the geometrical optics (high-frequency) regime. Comparisons with other approaches are presented for both scalar and elastic waves. PMID:22423683
NASA Technical Reports Server (NTRS)
Weissman, D. E.; Johnson, J. W.
1986-01-01
The directional spectrum and the microwave modulation transfer function of ocean waves can be measured with the airborne two frequency scatterometer technique. Similar to tower based observations, the aircraft measurements of the Modulation Transfer Function (MTF) show that it is strongly affected by both wind speed and sea state. Also detected are small differences in the magnitudes of the MTF between downwind and upwind radar look directions, and variations with ocean wavenumber. The MTF inferred from the two frequency radar is larger than that measured using single frequency, wave orbital velocity techniques such as tower based radars or ROWS measurements from low altitude aircraft. Possible reasons for this are discussed. The ability to measure the ocean directional spectrum with the two frequency scatterometer, with supporting MTF data, is demonstrated.
An investigation of nodal structures and the construction of trial wave functions
NASA Astrophysics Data System (ADS)
Bressanini, Dario; Morosi, Gabriele; Tarasco, Silvia
2005-11-01
The factors influencing the quality of the nodal surfaces, namely, the atomic basis set, the single-particle orbitals, and the configurations included in the wave-function expansion, are examined for a few atomic and molecular systems. The following empirical rules are found: the atomic basis set must be fairly large, complete active space and natural orbitals are usually better than Hartree-Fock orbitals, multiconfiguration expansions perform better than single-determinant wave functions, but only few configurations are effective and their choice is suggested by symmetry considerations, while too long determinantal expansions spoil the nodal surfaces. These rules allow us to reduce the nodal error and to compute the best fixed node-diffusion Monte Carlo energies for a series of dimers of first-row atoms.
The Hartle-Hawking wave function in 2D causal set quantum gravity
NASA Astrophysics Data System (ADS)
Glaser, Lisa; Surya, Sumati
2016-03-01
We define the Hartle-Hawking no-boundary wave function for causal set theory (CST) over the discrete analogs of spacelike hypersurfaces. Using Markov Chain Monte Carlo and numerical integration methods we analyze the wave function in non-perturbative 2D CST. We find that in the low-temperature regime it is dominated by causal sets which have no continuum counterparts but possess physically interesting geometric properties. Not only do they exhibit a rapid spatial expansion with respect to the discrete proper time, but a high degree of spatial homogeneity. The latter is due to the extensive overlap of the causal pasts of the elements in the final discrete hypersurface and corresponds to high graph connectivity. Our results thus suggest new possibilities for the role of quantum gravity in the observable Universe.
NASA Astrophysics Data System (ADS)
Sarsa, A.; Buendía, E.; Gálvez, F. J.
2016-07-01
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.
Donor wave functions delocalization in silicon nanowires: the peculiar [011] orientation.
Petretto, Guido; Debernardi, Alberto; Fanciulli, Marco
2013-10-01
The localization of the donor electron wave function can be of key importance in various silicon applications, since for example it determines the interactions between neighboring donors. Interestingly, the physical confinement of the electrons in quasi-one-dimensional nanostructures, like silicon nanowires, noticeably affects this property. Using fully ab initio calculations, we show that the delocalization of the donor electron wave function along the axis of a nanowire is much greater in [011] oriented nanowires for phosphorus and selenium donors. We also demonstrate that its value can be controlled by applying a compressive or tensile uniaxial strain. Finally, we discuss the implications of these features from both an experimental and a theoretical point of view. PMID:23984940
Calculations of properties of screened He-like systems using correlated wave functions.
Dai, S T; Solovyova, A; Winkler, P
2001-07-01
The purpose of the present study is twofold. First, the techniques of correlated wave functions for two-electron systems have been extended to obtain results for P and D states in a screening environment, and in particular for Debye screening. In these calculations, the satisfaction of both the quantum virial theorem and a related sum rule has been enforced and found to provide a high degree of stability of the solutions. Second, in order to facilitate the general use of correlated wave functions in combination with sum rule stability criteria, a rather systematic computational approach to this notoriously cumbersome method has been developed and thoroughly discussed here. Accurate calculations for few-electron systems are of interest to plasma diagnostics; in particular, when inaccuracies in binding energies are drastically magnified as they occur in exponents of Boltzmann factors. PMID:11461411
Auxiliary-field based trial wave functions in quantum Monte Carlo simulations
NASA Astrophysics Data System (ADS)
Chang, Chia-Chen; Rubenstein, Brenda; Morales, Miguel
We propose a simple scheme for generating correlated multi-determinant trial wave functions for quantum Monte Carlo algorithms. The method is based on the Hubbard-Stratonovich transformation which decouples a two-body Jastrow-type correlator into one-body projectors coupled to auxiliary fields. We apply the technique to generate stochastic representations of the Gutzwiller wave function, and present benchmark resuts for the ground state energy of the Hubbard model in one dimension. Extensions of the proposed scheme to chemical systems will also be discussed. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344, 15-ERD-013.
Library of sophisticated functions for analysis of nuclear spectra
NASA Astrophysics Data System (ADS)
Morháč, Miroslav; Matoušek, Vladislav
2009-10-01
In the paper we present compact library for analysis of nuclear spectra. The library consists of sophisticated functions for background elimination, smoothing, peak searching, deconvolution, and peak fitting. The functions can process one- and two-dimensional spectra. The software described in the paper comprises a number of conventional as well as newly developed methods needed to analyze experimental data. Program summaryProgram title: SpecAnalysLib 1.1 Catalogue identifier: AEDZ_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEDZ_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 42 154 No. of bytes in distributed program, including test data, etc.: 2 379 437 Distribution format: tar.gz Programming language: C++ Computer: Pentium 3 PC 2.4 GHz or higher, Borland C++ Builder v. 6. A precompiled Windows version is included in the distribution package Operating system: Windows 32 bit versions RAM: 10 MB Word size: 32 bits Classification: 17.6 Nature of problem: The demand for advanced highly effective experimental data analysis functions is enormous. The library package represents one approach to give the physicists the possibility to use the advanced routines simply by calling them from their own programs. SpecAnalysLib is a collection of functions for analysis of one- and two-parameter γ-ray spectra, but they can be used for other types of data as well. The library consists of sophisticated functions for background elimination, smoothing, peak searching, deconvolution, and peak fitting. Solution method: The algorithms of background estimation are based on Sensitive Non-linear Iterative Peak (SNIP) clipping algorithm. The smoothing algorithms are based on the convolution of the original data with several types of filters and algorithms based on discrete
Nuclear Containment Inspection Using AN Array of Guided Wave Sensors for Damage Localization
NASA Astrophysics Data System (ADS)
Cobb, A. C.; Fisher, J. L.
2010-02-01
Nuclear power plant containments are typically both the last line of defense against the release of radioactivity to the environment and the first line of defense to protect against intrusion from external objects. As such, it is important to be able to locate any damage that would limit the integrity of the containment itself. Typically, a portion of the containment consists of a metallic pressure boundary that encloses the reactor primary circuit. It is made of thick steel plates welded together, lined with concrete and partially buried, limiting areas that can be visually inspected for corrosion damage. This study presents a strategy using low frequency (<50 kHz) guided waves to find corrosion-like damage several meters from the probe in a mock-up of the containment vessel. A magnetostrictive sensor (MsS) is scanned across the width of the vessel, acquiring waveforms at a fixed interval. A beam forming strategy is used to localize the defects. Experimental results are presented for a variety of damage configurations, demonstrating the efficacy of this technique for detecting damage smaller than the ultrasonic wavelength.
Nuclear receptor-induced transcription is driven by spatially and timely restricted waves of ROS
Perillo, Bruno; Di Santi, Annalisa; Cernera, Gustavo; Ombra, Maria Neve; Castoria, Gabriella; Migliaccio, Antimo
2014-01-01
Gene expression is governed by chromatin mainly through posttranslational modifications at the N-terminal tails of nucleosomal histone proteins. According to the histone code theory, peculiar sets of such modifications (marks) give rise to reproducible final effects on transcription and, very recently, a further level of complexity has been highlighted in binary switches between specific marks at adjacent residues. In particular, disappearance of dimethyl-lysine 9 in histone H3 is faced by phosphorylation of the following serine during activation of gene expression. Demethylation of lysine 9 by the lysine-specific demethylase 1 (LSD1) is a pre-requisite for addition of the phosphoryl mark to serine 10 and an essential step in the transcriptional control by estrogens. It generates a local burst of oxygen reactive species (ROS) that induce oxidation of nearby nucleotides and recruitment of repair enzymes with a consequent formation of single or double stranded nicks on DNA that modify chromatin flexibility in order to allow correct assembly of the transcriptional machinery. We describe here the molecular mechanism by which members of the family of nuclear receptors prevent the potential damage to DNA during transcription of target genes elicited by the use of ROS to shape chromatin. The mechanism is based on the presence of phosphorylated serine 10 in histone H3 to prevent unbalanced DNA oxidation waves. We also discuss the opportunities raised by the use of voluntary derangement of this servo system to induce selective death in hormone-responsive transformed cells. PMID:25482200
Quantum statistical foundation to the Fermi liquid model and Ginzburg-Landau wave function
Fujita, Shigeji; Godoy, S. )
1993-12-01
An energy eigenvalue equation for a quasi-particle is derived, starting with the Heisenberg equation of motion for an annihilation operator. An elementary derivation of the Fermi liquid model having a sharply defined Fermi surface in the k-space is given, starting with a realistic model of a metal including the Coulomb interaction among and between electrons and lattice-ions. The Ginzburg-Landau wave function [Psi][sub [sigma
Working With the Wave Equation in Aeroacoustics: The Pleasures of Generalized Functions
NASA Technical Reports Server (NTRS)
Farassat, F.; Brentner, Kenneth S.; Dunn, mark H.
2007-01-01
The theme of this paper is the applications of generalized function (GF) theory to the wave equation in aeroacoustics. We start with a tutorial on GFs with particular emphasis on viewing functions as continuous linear functionals. We next define operations on GFs. The operation of interest to us in this paper is generalized differentiation. We give many applications of generalized differentiation, particularly for the wave equation. We discuss the use of GFs in finding Green s function and some subtleties that only GF theory can clarify without ambiguities. We show how the knowledge of the Green s function of an operator L in a given domain D can allow us to solve a whole range of problems with operator L for domains situated within D by the imbedding method. We will show how we can use the imbedding method to find the Kirchhoff formulas for stationary and moving surfaces with ease and elegance without the use of the four-dimensional Green s theorem, which is commonly done. Other subjects covered are why the derivatives in conservation laws should be viewed as generalized derivatives and what are the consequences of doing this. In particular we show how we can imbed a problem in a larger domain for the identical differential equation for which the Green s function is known. The primary purpose of this paper is to convince the readers that GF theory is absolutely essential in aeroacoustics because of its powerful operational properties. Furthermore, learning the subject and using it can be fun.
Many-body Localization Transition in Rokhsar-Kivelson-type wave functions
NASA Astrophysics Data System (ADS)
Chen, Xiao; Yu, Xiongjie; Cho, Gil Young; Clark, Bryan; Fradkin, Eduardo
We construct a family of many-body wave functions to study the many-body localization phase transition. The wave functions have a Rokhsar-Kivelson form, in which the weight for the configurations are chosen from the Gibbs weights of a classical spin glass model, known as the Random Energy Model, multiplied by a random sign structure to represent a highly excited state. These wave functions show a phase transition into an MBL phase. In addition, we see three regimes of entanglement scaling with subsystem size: scaling with entanglement corresponding to an infinite temperature thermal phase, constant scaling, and a sub-extensive scaling between these limits. Near the phase transition point, the fluctuations of the Renyi entropies are non-Gaussian. We find that Renyi entropies with different Renyi index transition into the MBL phase at different points and have different scaling behavior, suggesting a multifractal behavior. This work was supported in part by DMR-1064319 and DMR-1408713 (XC,GYC,EF) at the University of Illinois, PHY11-25915 at KITP (EF), DOE, SciDAC FG02-12ER46875 (BKC and XY), and the Brain Korea 21 PLUS Project of Korea Government (GYC).
Extracting the density profile of an electronic wave function in a quantum dot
NASA Astrophysics Data System (ADS)
Boyd, Erin E.; Westervelt, Robert M.
2011-11-01
We use a model of a one-dimensional nanowire quantum dot to demonstrate the feasibility of a scanning probe microscope (SPM) imaging technique that can extract both the energy of an electron state and the amplitude of its wave function using a single instrument. This imaging technique can probe electrons that are buried beneath the surface of a low-dimensional semiconductor structure and provide valuable information for the design of quantum devices. A conducting SPM tip, acting as a movable gate, measures the energy of an electron state using Coulomb blockade spectroscopy. When the tip is close to the nanowire dot, it dents the wave function Ψ(x) of the quantum state, changing the electron's energy by an amount proportional to |Ψ(x)|2. By recording the change in energy as the SPM tip is moved along the length of the dot, the density profile of the electronic wave function can be found along the length of the quantum dot.
Emergence of complex and spinor wave functions in scale relativity. I. Nature of scale variables
Nottale, Laurent; Célérier, Marie-Noëlle
2013-11-15
One of the main results of scale relativity as regards the foundation of quantum mechanics is its explanation of the origin of the complex nature of the wave function. The scale relativity theory introduces an explicit dependence of physical quantities on scale variables, founding itself on the theorem according to which a continuous and non-differentiable space-time is fractal (i.e., scale-divergent). In the present paper, the nature of the scale variables and their relations to resolutions and differential elements are specified in the non-relativistic case (fractal space). We show that, owing to the scale-dependence which it induces, non-differentiability involves a fundamental two-valuedness of the mean derivatives. Since, in the scale relativity framework, the wave function is a manifestation of the velocity field of fractal space-time geodesics, the two-valuedness of velocities leads to write them in terms of complex numbers, and yields therefore the complex nature of the wave function, from which the usual expression of the Schrödinger equation can be derived.
Bond Breaking of Simple Molecules in Auxiliary-Field Quantum Monte Carlo with GVB Wave Functions
NASA Astrophysics Data System (ADS)
Purwanto, Wirawan; Krakauer, Henry; Zhang, Shiwei; Al-Saidi, Wissam
2007-03-01
Accurate potential energy curves are an essential ingredient in understanding chemical reactions. This problem spans a wide range of correlations, with correlation effects being the most important in the bond-breaking regime. We report potential energy curves of simple molecules, including water and the carbon dimer, within the framework of the auxiliary-field quantum Monte Carlo (AFQMC) method. AFQMC projects the many-body ground-state from a trial wave function, which is also used to control the sign/phase problem. A previous calculation showed that AFQMC could provide a fairly uniform description of the bond stretching of a water molecule, even with a simple unrestricted Hartree-Fock (UHF) trial wave function. We investigate the use of Generalized Valence Bond (GVB). GVB gives a better description of the molecule than UHF; so it is a simple yet efficient alternative to using a single Slater determinant trial wave function. We will compare AFQMC results with other correlated methods and the exact configuration interaction calculations. Al-Saidi, Zhang, Krakauer, J. Chem. Phys. 124, 224101 (2006)
NASA Astrophysics Data System (ADS)
Khan, Shehryar; Kubica-Misztal, Aleksandra; Kruk, Danuta; Kowalewski, Jozef; Odelius, Michael
2015-01-01
The zero-field splitting (ZFS) of the electronic ground state in paramagnetic ions is a sensitive probe of the variations in the electronic and molecular structure with an impact on fields ranging from fundamental physical chemistry to medical applications. A detailed analysis of the ZFS in a series of symmetric Gd(III) complexes is presented in order to establish the applicability and accuracy of computational methods using multiconfigurational complete-active-space self-consistent field wave functions and of density functional theory calculations. The various computational schemes are then applied to larger complexes Gd(III)DOTA(H2O)-, Gd(III)DTPA(H2O)2-, and Gd(III)(H2O)83+ in order to analyze how the theoretical results compare to experimentally derived parameters. In contrast to approximations based on density functional theory, the multiconfigurational methods produce results for the ZFS of Gd(III) complexes on the correct order of magnitude.
NASA Astrophysics Data System (ADS)
Arutyunyan, R. V.; Akhrameev, E. V.; Bolshov, L. A.; Kondratenko, P. S.; Tkalya, E. V.
2014-02-01
The possible regimes of the propagation of a self-sustained fluorescence wave of long-lived nuclear isomers, which is initiated by transitions to the nearest short-lived level owing to the absorption of X-ray photons and inelastic collisions of electrons in a plasma, have been analyzed. It has been found that, when the energy exchange between the nuclear subsystem and plasma is due to absorption and emission of photons, the fluorescence wave can propagate in the fast (with a near-light velocity) deflagration regime induced by the radiative heat transfer mechanism. When the energy exchange between the subsystems is nonradiative, the (slower) detonation regime becomes significant. The implementation of each of the two regimes requires certain conditions on the characteristics of the system.
NASA Astrophysics Data System (ADS)
Lu, Lu; Wang, Zhiqiang; Zhang, Pengfei; Qiao, Chunhong; Fan, Chengyu; Zhang, Jinghui; Ji, Xiaoling
2015-08-01
Based on the characteristics of a hypergeometric function, the analytical expressions for the phase structure function and angle-of-arrival (AOA) fluctuations of plane and spherical waves propagating through oceanic turbulence are derived. The results are verified by comparing them with the numerical calculations of the definitions using four important parameters (i.e., the rate of dissipation of mean-squared temperature {χ }T, the rate of dissipation of kinetic energy per unit mass of fluid \\varepsilon , the ratio of temperature to salinity contribution to the refractive index spectrum w, and the Kolmogorov microscale η ). The relation between AOA fluctuations and the spatial coherence radius {ρ }0 is also investigated.
Acute effect of alcohol intake on sine-wave Cartesian and polar contrast sensitivity functions
Cavalcanti-Galdino, M.K.; da Silva, J.A.; Mendes, L.C.; dos Santos, N.A.; Simas, M.L.B.
2014-01-01
The aim of this study was to assess contrast sensitivity for angular frequency stimuli as well as for sine-wave gratings in adults under the effect of acute ingestion of alcohol. We measured the contrast sensitivity function (CSF) for gratings of 0.25, 1.25, 2.5, 4, 10, and 20 cycles per degree of visual angle (cpd) as well as for angular frequency stimuli of 1, 2, 4, 24, 48, and 96 cycles/360°. Twenty adults free of ocular diseases, with normal or corrected-to-normal visual acuity, and no history of alcoholism were enrolled in two experimental groups: 1) no alcohol intake (control group) and 2) alcohol ingestion (experimental group). The average concentration of alcohol in the experimental group was set to about 0.08%. We used a paradigm involving a forced-choice method. Maximum sensitivity to contrast for sine-wave gratings in the two groups occurred at 4 cpd sine-wave gratings and at 24 and 48 cycles/360° for angular frequency stimuli. Significant changes in contrast sensitivity were observed after alcohol intake compared with the control condition at spatial frequency of 4 cpd and 1, 24, and 48 cycles/360° for angular frequency stimuli. Alcohol intake seems to affect the processing of sine-wave gratings at maximum sensitivity and at the low and high frequency ends for angular frequency stimuli, both under photopic luminance conditions. PMID:24676473
Mitri, Farid
2014-11-01
The generalized theory of resonance scattering (GTRS) by an elastic spherical target in acoustics is extended to describe the arbitrary scattering of a finite beam using the addition theorem for the spherical wave functions of the first kind under a translation of the coordinate origin. The advantage of the proposed method over the standard discrete spherical harmonics transform previously used in the GTRS formalism is the computation of the off-axial beam-shape coefficients (BSCs) stemming from a closed-form partial-wave series expansion representing the axial BSCs in spherical coordinates. With this general method, the arbitrary acoustical scattering can be evaluated for any particle shape and size, whether the particle is partially or completely illuminated by the incident beam. Numerical examples for the axial and off-axial resonance scattering from an elastic sphere placed arbitrarily in the field of a finite circular piston transducer with uniform vibration are provided. Moreover, the 3-D resonance directivity patterns illustrate the theory and reveal some properties of the scattering. Numerous applications involving the scattering phenomenon in imaging, particle manipulation, and the characterization of multiphase flows can benefit from the present analysis because all physically realizable beams radiate acoustical waves from finite transducers as opposed to waves of infinite extent. PMID:25389166
Determination of simple correlated wave functions for few-electron systems using a Jastrow factor
Umezawa, N.; Sarsa, A.; Le Sech, C.; Chikyow, T.
2006-01-15
Compact Jastrow-Slater-type correlated wave functions for three- and four-electron atoms and ions (Li, Be{sup +}, B{sup 2+}, C{sup 3+}, Be, B{sup +}, and C{sup 2+}) are proposed. The Jastrow factor we employed consists of one-body and two-body functions including only two variational parameters in total. We found that a one-body Jastrow function with one variational parameter, which is responsible for the screening effect around the nucleus, is effective for reproducing good total energies of the three- and four-electron atomic systems if hydrogenoid orbitals are adopted in the Slater determinant. On the other hand, a determinant composed of Hartree-Fock orbitals multiplied by the same Jastrow factor was found to give rather worse results than that composed of hydrogenoid orbitals. This result clearly indicates that analytic hydrogenoid orbitals coupled with the one-body Jastrow function are useful for describing simple wave functions and understanding the physical properties of these systems.
NASA Astrophysics Data System (ADS)
Katsuki, Hiroyuki; Kayanuma, Yosuke; Ohmori, Kenji
2013-07-01
Local excitations of indistinguishable particles in a solid are quantum-mechanically superposed to give delocalized wave functions. Their interference is often so short-lived that it eludes observation and manipulation. Here we have actively controlled interference of delocalized vibrational wave functions in solid para-hydrogen produced by a pair of ultrashort laser pulses. The ultrafast evolution of their interference changes from almost completely constructive (amplification by a factor of ˜4) to destructive when we change the timing of those two laser pulses by only 4 fs. This active control serves as an experimental tool to investigate the spatiotemporal evolution of a wave function in a bulk solid.
Progress at the interface of wave-function and density-functional theories
Gidopoulos, Nikitas I.
2011-04-15
The Kohn-Sham (KS) potential of density-functional theory (DFT) emerges as the minimizing effective potential in a variational scheme that does not involve fixing the unknown single-electron density. Using Rayleigh Schroedinger (RS) perturbation theory (PT), we construct ab initio approximations for the energy difference, the minimization of which determines the KS potential directly - thereby bypassing DFT's traditional algorithm to search for the density that minimizes the total energy. From second-order RS PT, we obtain variationally stable energy differences to be minimized, solving the severe problem of variational collapse of orbital-dependent exchange-correlation functionals based on second-order RS PT.
Crustal structure of Nigeria and Southern Ghana, West Africa from P-wave receiver functions
NASA Astrophysics Data System (ADS)
Akpan, Ofonime; Nyblade, Andrew; Okereke, Chiedu; Oden, Michael; Emry, Erica; Julià, Jordi
2016-04-01
We report new estimates of crustal thickness (Moho depth), Poisson's ratio and shear-wave velocities for eleven broadband seismological stations in Nigeria and Ghana. Data used for this study came from teleseismic earthquakes recorded at epicentral distances between 30° and 95° and with moment magnitudes greater than or equal to 5.5. P-wave receiver functions were modeled using the Moho Ps arrival times, H-k stacking, and joint inversion of receiver functions and Rayleigh wave group velocities. The average crustal thickness of the stations in the Neoproterozoic basement complex of Nigeria is 36 km, and 23 km for the stations in the Cretaceous Benue Trough. The crustal structure of the Paleoproterozoic Birimian Terrain, and Neoproterozoic Dahomeyan Terrain and Togo Structural Unit in southern Ghana is similar, with an average Moho depth of 44 km. Poisson's ratios for all the stations range from 0.24 to 0.26, indicating a bulk felsic to intermediate crustal composition. The crustal structure of the basement complex in Nigeria is similar to the average crustal structure of Neoproterozoic terrains in other parts of Africa, but the two Neoproterozoic terrains in southern Ghana have a thicker crust with a thick mafic lower crust, ranging in thickness from 12 to 17 km. Both the thicker crust and thick mafic lower crustal section are consistent with many Precambrian suture zones, and thus we suggest that both features are relict from the collisional event during the formation of Gondwana.
Matsui, Teppei; Murakami, Tomonari; Ohki, Kenichi
2016-06-01
Resting-state functional connectivity (FC), which measures the correlation of spontaneous hemodynamic signals (HemoS) between brain areas, is widely used to study brain networks noninvasively. It is commonly assumed that spatial patterns of HemoS-based FC (Hemo-FC) reflect large-scale dynamics of underlying neuronal activity. To date, studies of spontaneous neuronal activity cataloged heterogeneous types of events ranging from waves of activity spanning the entire neocortex to flash-like activations of a set of anatomically connected cortical areas. However, it remains unclear how these various types of large-scale dynamics are interrelated. More importantly, whether each type of large-scale dynamics contributes to Hemo-FC has not been explored. Here, we addressed these questions by simultaneously monitoring neuronal calcium signals (CaS) and HemoS in the entire neocortex of mice at high spatiotemporal resolution. We found a significant relationship between two seemingly different types of large-scale spontaneous neuronal activity-namely, global waves propagating across the neocortex and transient coactivations among cortical areas sharing high FC. Different sets of cortical areas, sharing high FC within each set, were coactivated at different timings of the propagating global waves, suggesting that spatial information of cortical network characterized by FC was embedded in the phase of the global waves. Furthermore, we confirmed that such transient coactivations in CaS were indeed converted into spatially similar coactivations in HemoS and were necessary to sustain the spatial structure of Hemo-FC. These results explain how global waves of spontaneous neuronal activity propagating across large-scale cortical network contribute to Hemo-FC in the resting state. PMID:27185944
The wave function and minimum uncertainty function of the bound quadratic Hamiltonian system
NASA Technical Reports Server (NTRS)
Yeon, Kyu Hwang; Um, Chung IN; George, T. F.
1994-01-01
The bound quadratic Hamiltonian system is analyzed explicitly on the basis of quantum mechanics. We have derived the invariant quantity with an auxiliary equation as the classical equation of motion. With the use of this invariant it can be determined whether or not the system is bound. In bound system we have evaluated the exact eigenfunction and minimum uncertainty function through unitary transformation.
David McKee
2003-05-01
High statistics elastic and quasielastic scattering measurements were performed on hydrogen, deuterium, carbon, and iron at squared momentum transfers up to 8.1 GeV2. Both the nuclear transparency and the single particle spectral functions were extracted by means of comparison with a Plane- Wave Impulse Approximation calculation. Our data provide no evidence of the onset of color transparency within our kinematic range.
Stafford, L.; Margot, J.; Moisan, M.; Khare, R.; Donnelly, V. M.
2009-01-12
Electron energy distribution functions (EEDFs) were measured in a 50 mTorr oxygen plasma column sustained by propagating surface waves. Trace-rare-gas-optical-emission spectroscopy was used to derive EEDFs by selecting lines to extract ''electron temperature''(T{sub e}) corresponding to either lower energy electrons that excite high-lying levels through stepwise excitation via metastable states or higher energy electrons that excite emission directly from the ground state. Lower energy T{sub e}'s decreased from 8 to 5.5 eV with distance from the wave launcher, while T{sub e}{approx_equal}6 eV for higher energy electrons and T{sub e}>20 eV for a high-energy tail. Mechanisms for such EEDFs are discussed.
7Be(p,(gamma))8B S-factor from Ab Initio No-Core Shell Model Wave Functions
Navratil, P; Bertulani, C A; Caurier, E
2005-12-02
Nuclear structure of {sup 7}Be, {sup 8}B and {sup 7,8}Li is studied within the ab initio no-core shell model (NCSM). Starting from high-precision nucleon-nucleon (NN) interactions, wave functions of {sup 7}Be and {sup 8}B bound states are obtained in basis spaces up to 10 h bar{Omega} and used to calculate channel cluster form factors (overlap integrals) of the {sup 8}B ground state with {sup 7}Be+p. Due to the use of the harmonic oscillator (HO) basis, the overlap integrals have incorrect asymptotic properties. We fix this problem in two alternative ways. First, by a Woods-Saxon (WS) potential solution fit to the interior of the NCSM overlap integrals. Second, by a direct matching with the Whittaker function. The corrected overlap integrals are then used for the {sup 7}Be(p,{gamma}){sup 8}B S-factor calculation. We study the convergence of the S-factor with respect to the NCSM HO frequency and the model space size. Our S-factor results are in agreement with recent direct measurement data. We also test the spectroscopic factors and the corrected overlap integrals from the NCSM in describing the momentum distributions in knockout reactions with {sup 8}B projectiles. A good agreement with the available experimental data is also found, attesting the overall consistency of the calculations.
Fattebert, J
2008-07-29
We describe an iterative algorithm to solve electronic structure problems in Density Functional Theory. The approach is presented as a Subspace Accelerated Inexact Newton (SAIN) solver for the non-linear Kohn-Sham equations. It is related to a class of iterative algorithms known as RMM-DIIS in the electronic structure community. The method is illustrated with examples of real applications using a finite difference discretization and multigrid preconditioning.
Roshchina, G Ia; Koroleva, V I; Davydov, V I
2012-01-01
EEG aftereffects of spreading depression waves were studied in waking rabbits in chronic experiments by spectral coherence analysis. Experiments were divided in two groups: early (from the first to the third-fourth experiments) and late (fifth-tenth experiments). During the early experimental series, unilateral persistent EEG changes consisting in an increase in the delta- and beta-band power with a simultaneous depression of the gamma-band activity were observed in the ipsilateral to SD hemisphere. In addition, interhemispheric coherence between symmetrical cortical points decreased. During the late experimental series, a generalized bilateral increase in the power of the delta and beta activity was demonstrated with a rise in coherence in the beta band. This generalized activity occurred cyclically and was distinct during a long period of time (2-3 hours) after propagation of a single SD wave. Such kind of cyclical activity blocked the propagation of subsequent SD waves in the neocortex of a waking rabbit and decreased the probability of recurrent wave origin up to a complete cessation of wave generation. Thus, a cortical SD wave provoked the appearance of synchronized beta oscillations in the EEG, which in turn actively influenced the properties of recurrent waves. PMID:23227733
Averkiev, Boris B; Zhao, Yan; Truhlar, Donald G
2010-06-01
The structures of Pd(PH₃)₂ and Pt(PH₃)₂ complexes with ethene and conjugated CnH_{n+2} systems (n=4, 6, 8, and 10) were studied. Their binding energies were calculated using both wave function theory (WFT) and density functional theory (DFT). Previously it was reported that the binding energy of the alkene to the transition metal does not depend strongly on the size of the conjugated C_{n}H_{n+2} ligand, but that DFT methods systematically underestimate the binding energy more and more significantly as the size of the conjugated system is increased. Our results show that recently developed density functionals predict the binding energy for these systems much more accurately. New benchmark calculations carried out by the coupled cluster method based on Brueckner orbitals with double excitations and a quasiperturbative treatment of connected triple excitations (BCCD(T)) with a very large basis set agree even better with the DFT predictions than do the previous best estimates. The mean unsigned error in absolute and relative binding energies of the alkene ligands to Pd(PH₃)₂ is 2.5 kcal/mol for the ωB97 and M06 density functionals and 2.9 kcal/mol for the M06-L functional. Adding molecular mechanical damped dispersion yields even smaller mean unsigned errors: 1.3 kcal/mol for the M06-D functional, 1.5 kcal/mol for M06- L-D, and 1.8 kcal/mol for B97-D and ωB97X-D. The new functionals also lead to improved accuracy for the analogous Pt complexes. These results show that recently developed density functionals may be very useful for studying catalytic systems involving Pd d¹º centers and alkenes.
NASA Astrophysics Data System (ADS)
Patil, S. H.; Tang, K. T.; Toennies, J. P.
1999-10-01
Simple analytical wave functions satisfying appropriate boundary conditions are constructed for the ground states of one-and two-electron homonuclear molecules. Both the asymptotic condition when one electron is far away and the cusp condition when the electron coalesces with a nucleus are satisfied by the proposed wave function. For H2+, the resulting wave function is almost identical to the Guillemin-Zener wave function which is known to give very good energies. For the two electron systems H2 and He2++, the additional electron-electron cusp condition is rigorously accounted for by a simple analytic correlation function which has the correct behavior not only for r12→0 and r12→∞ but also for R→0 and R→∞, where r12 is the interelectronic distance and R, the internuclear distance. Energies obtained from these simple wave functions agree within 2×10-3 a.u. with the results of the most sophisticated variational calculations for all R and for all systems studied. This demonstrates that rather simple physical considerations can be used to derive very accurate wave functions for simple molecules thereby avoiding laborious numerical variational calculations.
Constraining the Lithospheric Structure of the Central Andes Using P- and S- wave Receiver Functions
NASA Astrophysics Data System (ADS)
Ryan, J. C.; Beck, S. L.; Zandt, G.; Wagner, L. S.; Minaya, E.; Tavera, H.
2014-12-01
The Central Andean Plateau (CAP) has elevations in excess of 3 km, and is part of the Andean Cordillera that resulted in part from shortening along the western edge of South America as it was compressed between the subducting Nazca plate and underthrusting Brazilian cratonic lithosphere. We calculated P- and S-wave receiver functions for the Central Andean Uplift and Geodynamics of High Topography (CAUGHT) temporary deployment of broadband seismometers in the Bolivian orocline (12°-20°S) region to investigate crustal thickness and lithospheric structure. Migration of the receiver functions is done using common conversion point (CCP) stacks through a 3D shear velocity model from ambient noise tomography (Ward et al., 2013). The P- and S-wave receiver functions provide similar estimates of the depth to Moho under the CAP. Crustal thicknesses include 60-65 km thick crust underneath the Bolivian Altiplano, crust that varies from ~70 km to ~50 km underneath the Eastern Cordillera and Interandean zone, and thins to 50 to 40 km crust in the Subandes and the edge of the foreland. The variable crustal thickness of the Eastern Cordillera and Interandean zone ranges from >70 km associated with the Los Frailes volcanic field at 19°-20°S to ~55 km beneath the 6 km peaks of the Cordillera Real at ~16°S. From our S-wave receiver functions, that have no multiples that can interfere with deeper structure, we also identify structures below the Moho. Along a SW-NE line that runs near La Paz where we have our highest station density, the S-wave CCP receiver-function stacks show a strong negative polarity arrival at a depth of ~120 km from the eastern edge of the Altiplano to the Subandean zone. We suggest this may be a good candidate for the base of the CAP lithosphere. In addition, above this depth the mantle is strongly layered, suggesting that there is not a simple high velocity mantle lithosphere associated with the continental lithosphere underthrusting the Andean orogen
NASA Astrophysics Data System (ADS)
Yang, Yu; Maruyama, S.; Fossen, A.; Villers, F.; Kiss, G.; Zhang, Bo; Li, Bo; Jiang, Tao; Huang, Xiangmei
2016-08-01
The ITER Gas Injection System (GIS) plays an important role on fueling, wall conditioning and distribution for plasma operation. Besides that, to support the safety function of ITER, GIS needs to implement three nuclear safety Instrumentation and Control (I&C) functions. In this paper, these three functions are introduced with the emphasis on their latest safety classifications. The nuclear I&C design concept is briefly discussed at the end.
Thierfelder, Christian; Schwerdtfeger, Peter; Saue, Trond
2007-09-15
The electric field gradient in late transition metal compounds is incorrectly determined by most density functionals. We show that the coupling of short-range density functional based with long-range wave function based methods using a reparametrization of the Coulomb-attenuated Becke three-parameter Lee-Yang-Parr approximation gives reliable results for the electric field gradients of copper and gold for a series of compounds. This results in nuclear quadrupole moments of -0.208 b for {sup 63}Cu and +0.526 b for {sup 197}Au in good agreement with experimental values of -0.220(15) and +0.547(16)b, respectively.
Fattebert, J.-L.
2010-01-20
An Accelerated Block Preconditioned Gradient (ABPG) method is proposed to solve electronic structure problems in Density Functional Theory. This iterative algorithm is designed to solve directly the non-linear Kohn-Sham equations for accurate discretization schemes involving a large number of degrees of freedom. It makes use of an acceleration scheme similar to what is known as RMM-DIIS in the electronic structure community. The method is illustrated with examples of convergence for large scale applications using a finite difference discretization and multigrid preconditioning.
Regularized quadratic cost-function for integrating wave-front gradient fields.
Villa, Jesús; Rodríguez, Gustavo; Ivanov, Rumen; González, Efrén
2016-05-15
From the Bayesian regularization theory we derive a quadratic cost-function for integrating wave-front gradient fields. In the proposed cost-function, the term of conditional distribution uses a central-differences model to make the estimated function well consistent with the observed gradient field. As will be shown, the results obtained with the central-differences model are superior to the results obtained with the backward-differences model, commonly used in other integration techniques. As a regularization term we use an isotropic first-order differences Markov Random-Field model, which acts as a low-pass filter reducing the errors caused by the noise. We present simulated and real experiments of the proposal applied in the Foucault test, obtaining good results. PMID:27176991
Bannister, S.; Bryan, C.J.; Bibby, H.M.
2004-01-01
The Taupo Volcanic Zone (TVZ), New Zealand is a region characterized by very high magma eruption rates and extremely high heat flow, which is manifest in high-temperature geothermal waters. The shear wave velocity structure across the region is inferred using non-linear inversion of receiver functions, which were derived from teleseismic earthquake data. Results from the non-linear inversion, and from forward synthetic modelling, indicate low S velocities at ???6- 16 km depth near the Rotorua and Reporoa calderas. We infer these low-velocity layers to represent the presence of high-level bodies of partial melt associated with the volcanism. Receiver functions at other stations are complicated by reverberations associated with near-surface sedimentary layers. The receiver function data also indicate that the Moho lies between 25 and 30 km, deeper than the 15 ?? 2 km depth previously inferred for the crust-mantle boundary beneath the TVZ. ?? 2004 RAS.
Efficient calculation of 1-D periodic Green's functions for leaky-wave applications.
Baccarelli, Paolo; Johnson, William Arthur; Paulotto, Simone; Jackson, David R.; Wilton, Donald R.; Galli, A.; Valero, G.; Celepcikay, F. T.
2010-08-01
In this paper an approach is described for the efficient computation of the mixed-potential scalar and dyadic Green's functions for a one-dimensional periodic (periodic along x direction) array of point sources embedded in a planar stratified structure. Suitable asymptotic extractions are performed on the slowly converging spectral series. The extracted terms are summed back through the Ewald method, modified and optimized to efficiently deal with all the different terms. The accelerated Green's functions allow for complex wavenumbers, and are thus suitable for application to leaky-wave antennas analysis. Suitable choices of the spectral integration paths are made in order to account for leakage effects and the proper/improper nature of the various space harmonics that form the 1-D periodic Green's function.
Source Time Functions of the Dprk Announced Nuclear TESTS of 2006, 2009 and 2013
NASA Astrophysics Data System (ADS)
Ziolkowski, A.
2014-12-01
The concept of source scaling is used to determine the source time functions of the three announced nuclear tests of 2006, 2009 and 2013 of the Democratic People's Republic of Korea (DPRK). Two explosions at essentially the same source location, but at different times, have scaled source time functions. In an x-y plot of these functions, the ground motion axis (y) and the time axis (x) scale by the same factor, which is the cube-root of the energy ratio. The seismograms from these two events, measured at a given seismometer, share the same path effect, or Earth impulse response. The two seismograms and the scaling law provide three equations that can be solved for the three principal unknowns: the two source time functions and the Earth impulse response. This concept is applied to seismograms recorded at Mudanjiang (MDJ) for the three DPRK events, using two novel steps. First, the spectral ratio of the two source time functions is calculated in the time domain directly from the seismograms. Second, the scale factor is calculated directly from the data. The energy partition is independent of event size. So the ratio of the energies of the P-waves, for example, is equal to the ratio of the source energies. The ratio of the energies of the Pn phase was computed for the 2009 and 2013 events. The scaling factor is the cube-root of this ratio. The source time functions of the 2009 and 2013 events were recovered using the two seismograms and the scaling law, and the seismograms were deconvolved for these source time functions to recover the Earth impulse response. If everything is done correctly the recovered Earth impulse response should be the same for each event. I show that the recovered impulse responses for the 2009 and 2013 events are nearly identical. Presuming the DPRK test site to be in granite, relative reduced displacement potentials for the three events give yields of 0.11, 1.98 and 7.11 kt, with errors up to 46 %.
NASA Astrophysics Data System (ADS)
Buendía, E.; Gálvez, F. J.; Maldonado, P.; Sarsa, A.
2014-11-01
Total energies calculated from explicitly correlated wave functions for the ground state of the atoms Li to Sr and their singly charged anions and cations are obtained. Accurate all electron, non-relativistic Variational and Diffusion Monte Carlo energies are reported. The quality of the results, when comparing with exact estimations and experimental electron affinities and ionization potential is similar for all of the atoms studied. The parameterization of the explicitly correlated wave functions for all of the atomic systems studied is provided.
Role of the bound-state wave function in capture-loss rates: Slow proton in an electron gas
Alducin, M.; Nagy, I.
2003-07-01
Capture and loss rates for protons moving in an electron gas are calculated using many-body perturbation theory. The role of the form of the bound-state wave function for weakly bound states around the proton is analyzed. We find significant differences (up to a factor of 2 higher) in the values of Auger capture and loss rates when using Hulthen-type instead of hydrogenic wave functions. Its relevance in stopping power is briefly discussed.
Bobrov, V B; Trigger, S A; van Heijst, G J F; Schram, P P J M
2010-07-01
On the basis of the stationary Schrödinger equation, the virial theorem in an inhomogeneous external field for the canonical ensemble is proved. It is shown that the difference in the form of virial theorem is conditioned by the value of the wave-function derivative on the surface of the volume, surrounding the system under consideration. The stress tensor in such a system is determined by the average values of the wave-function space derivatives. PMID:20866550
P-wave receiver function study of crustal structure in Scandinavia
NASA Astrophysics Data System (ADS)
Makushkina, Anna; Thybo, Hans; Vinnik, Lev; Youssof, Mohammad
2016-04-01
In this study we present preliminary results on the structure of the continental crust in northern Scandinavia. The research area consists of three geologically different domains: the Archaean Domain in the north-east, the Palaeoproterozoic Svecofennian Domain in the east and the Caledonian Deformed Domain in the west (Gorbatschev and Bogdanova,1993). We present results based on data collected by 60 seismic stations during 2-4 years of deployment in the ScanArray experiment, which is an international collaboration between Scandinavian, German and British universities. We use the receiver function (RF) technique in the LQT ray-oriented coordinate system (Vinnik, 1977). Receiver function analysis has rather high vertical resolution of the depth to seismic discontinuities which cause transformation between P- and S-waves. The whole dataset is uniformly filtered and deconvolved records are stacked using appropriate moveout corrections. We have used events with a magnitude ≥ 5.5 Mw, with epicentral distances range from 30° to 95°. The technique allows us to constrain crustal structure and determine the Moho depth around stations by analyzing the PS converted phases generated at discontinuities in particular the Moho. We present preliminary interpretation of P-wave RF analysis in terms of the complex tectonic and geodynamic evolution of the Baltic Shield. Further studies will include joint P and S receiver function analysis of this area as well as investigations of the upper mantle. References: Vinnik L.P. (1977) Detection of waves converted from P to SV in the mantle. Phys. Earth planet. Inter. 15, 39-45 Gorbatschev R., Bogdanova, S. (1993) Frontiers in the Baltic Shield. Precambrian Res. 64, 3-21
Big bounce as the scattering of the wave function at the big crunch
Amemiya, Fumitoshi; Koike, Tatsuhiko
2010-11-15
A gauge-invariant quantum theory of the Friedmann-Robertson-Walker (FRW) universe with dust is studied in terms of the Ashtekar variables. We use the reduced phase space quantization which has following advantages: (i) fundamental variables are all gauge invariant, (ii) there exists a physical time evolution of gauge-invariant quantities, so that the problem of time is absent, and (iii) the reduced phase space can be quantized in the same manner as in ordinary quantum mechanics. In the FRW model, the dynamical components of the Ashtekar variables are given by a single quantity p and its conjugate momentum, where p is related to the scale factor a as a{proportional_to}{radical}(|p|) and its sign gives the orientation of triads. We solve a scattering problem in terms of ingoing and outgoing energy eigenstates. We show that the incident wave is reflected in rate 1/4 and transmitted in rate 3/4 at the classical singularity p=0. Analyzing the dynamics of a wave packet, we show that the classical initial singularity is replaced by a big bounce in quantum theory. A possible interpretation of the result is that the wave function of the universe has been in a superposition of states representing right-handed and left-handed systems before the big bounce.
Evaluation of partial widths and branching ratios from resonance wave functions
Goldzak, Tamar; Gilary, Ido; Moiseyev, Nimrod
2010-11-15
A quantum system in a given resonance state has different open channels for decay. Partial widths are the decay rates of the resonance (metastable) state into the different open channels. Here we present a rigorous derivation of the partial widths from the solution of a time-dependent Schroedinger equation with outgoing boundary conditions. We show that the sum of the partial widths obtained from the resonance wave function is equal to the total width. The difference with respect to previous studies on partial widths and branching ratios is discussed.
Extracting elements of molecular structure from the all-particle wave function
Matyus, Edit; Reiher, Markus; Hutter, Juerg; Mueller-Herold, Ulrich
2011-11-28
Structural information is extracted from the all-particle (non-Born-Oppenheimer) wave function by calculating radial and angular densities derived from n-particle densities. As a result, one- and two-dimensional motifs of classical molecular structure can be recognized in quantum mechanics. Numerical examples are presented for three- (H{sup -}, Ps{sup -}, H{sub 2}{sup +}), four- (Ps{sub 2}, H{sub 2}), and five-particle (H{sub 2}D{sup +}) systems.
Efficient calculation of potential energy surfaces for the generation of vibrational wave functions
NASA Astrophysics Data System (ADS)
Rauhut, Guntram
2004-11-01
An automatic procedure for the generation of potential energy surfaces based on high level ab initio calculations is described. It allows us to determine the vibrational wave functions for molecules of up to ten atoms. Speedups in computer time of about four orders of magnitude in comparison to standard implementations were achieved. Effects due to introduced approximations—within the computation of the potential—on fundamental modes obtained from vibrational self-consistent field and vibrational configuration interaction calculations are discussed. Benchmark calculations are provided for formaldehyde and 1,2,5-oxadiazole (furazan).
Efficient calculation of potential energy surfaces for the generation of vibrational wave functions.
Rauhut, Guntram
2004-11-15
An automatic procedure for the generation of potential energy surfaces based on high level ab initio calculations is described. It allows us to determine the vibrational wave functions for molecules of up to ten atoms. Speedups in computer time of about four orders of magnitude in comparison to standard implementations were achieved. Effects due to introduced approximations--within the computation of the potential--on fundamental modes obtained from vibrational self-consistent field and vibrational configuration interaction calculations are discussed. Benchmark calculations are provided for formaldehyde and 1,2,5-oxadiazole (furazan). PMID:15538851
Wave-function inspired density functional applied to the H2/{{\\rm{H}}}_{2}^{+} challenge
NASA Astrophysics Data System (ADS)
Zhang, Igor Ying; Rinke, Patrick; Scheffler, Matthias
2016-07-01
We start from the Bethe–Goldstone equation (BGE) to derive a simple orbital-dependent correlation functional—BGE2—which terminates the BGE expansion at the second-order, but retains the self-consistent coupling of electron-pair correlations. We demonstrate that BGE2 is size consistent and one-electron ‘self-correlation’ free. The electron-pair correlation coupling ensures the correct H2 dissociation limit and gives a finite correlation energy for any system even if it has a no energy gap. BGE2 provides a good description of both H2 and {{{H}}}2+ dissociation, which is regarded as a great challenge in density functional theory (DFT). We illustrate the behavior of BGE2 analytically by considering H2 in a minimal basis. Our analysis shows that BGE2 captures essential features of the adiabatic connection path that current state-of-the-art DFT approximations do not.
Wood, Ashley M.; Garza-Gongora, Arturo G.; Kosak, Steven T.
2014-01-01
The spatial organization of the nucleus results in a compartmentalized structure that affects all aspects of nuclear function. This compartmentalization involves genome organization as well as the formation of nuclear bodies and plays a role in many functions, including gene regulation, genome stability, replication, and RNA processing. Here we review the recent findings associated with the spatial organization of the nucleus and reveal that a common theme for nuclear proteins is their ability to participate in a variety of functions and pathways. We consider this multiplicity of function in terms of Crowdsourcing, a recent phenomenon in the world of information technology, and suggest that this model provides a novel way to synthesize the many intersections between nuclear organization and function. PMID:24412853
Dechat, Thomas; Pfleghaar, Katrin; Sengupta, Kaushik; Shimi, Takeshi; Shumaker, Dale K.; Solimando, Liliana; Goldman, Robert D.
2008-01-01
Over the past few years it has become evident that the intermediate filament proteins, the types A and B nuclear lamins, not only provide a structural framework for the nucleus, but are also essential for many aspects of normal nuclear function. Insights into lamin-related functions have been derived from studies of the remarkably large number of disease-causing mutations in the human lamin A gene. This review provides an up-to-date overview of the functions of nuclear lamins, emphasizing their roles in epigenetics, chromatin organization, DNA replication, transcription, and DNA repair. In addition, we discuss recent evidence supporting the importance of lamins in viral infections. PMID:18381888
NASA Astrophysics Data System (ADS)
Regnier, D.; Dubray, N.; Schunck, N.; Verrière, M.
2016-05-01
Background: Accurate knowledge of fission fragment yields is an essential ingredient of numerous applications ranging from the formation of elements in the r process to fuel cycle optimization for nuclear energy. The need for a predictive theory applicable where no data are available, together with the variety of potential applications, is an incentive to develop a fully microscopic approach to fission dynamics. Purpose: In this work, we calculate the pre-neutron emission charge and mass distributions of the fission fragments formed in the neutron-induced fission of 239Pu using a microscopic method based on nuclear density functional theory (DFT). Methods: Our theoretical framework is the nuclear energy density functional (EDF) method, where large-amplitude collective motion is treated adiabatically by using the time-dependent generator coordinate method (TDGCM) under the Gaussian overlap approximation (GOA). In practice, the TDGCM is implemented in two steps. First, a series of constrained EDF calculations map the configuration and potential-energy landscape of the fissioning system for a small set of collective variables (in this work, the axial quadrupole and octupole moments of the nucleus). Then, nuclear dynamics is modeled by propagating a collective wave packet on the potential-energy surface. Fission fragment distributions are extracted from the flux of the collective wave packet through the scission line. Results: We find that the main characteristics of the fission charge and mass distributions can be well reproduced by existing energy functionals even in two-dimensional collective spaces. Theory and experiment agree typically within two mass units for the position of the asymmetric peak. As expected, calculations are sensitive to the structure of the initial state and the prescription for the collective inertia. We emphasize that results are also sensitive to the continuity of the collective landscape near scission. Conclusions: Our analysis confirms
NASA Astrophysics Data System (ADS)
Carlsson, B. G.; Dobaczewski, J.; Toivanen, J.; Veselý, P.
2010-09-01
We present solution of self-consistent equations for the N 3LO nuclear energy density functional. We derive general expressions for the mean fields expressed as differential operators depending on densities and for the densities expressed in terms of derivatives of wave functions. These expressions are then specified to the case of spherical symmetry. We also present the computer program HOSPHE (v1.02), which solves the self-consistent equations by using the expansion of single-particle wave functions on the spherical harmonic oscillator basis. Program summaryProgram title: HOSPHE (v1.02) Catalogue identifier: AEGK_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEGK_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 45 809 No. of bytes in distributed program, including test data, etc.: 290 514 Distribution format: tar.gz Programming language: Fortran-90 Computer: PCs and workstations Operating system: Linux RAM: 50 MB Classification: 17.22 External routines: LAPACK ( http://www.netlib.org/lapack/), BLAS ( http://www.netlib.org/blas/) Nature of problem: The nuclear mean-field methods constitute principal tools of a description of nuclear states in heavy nuclei. Within the Local Density Approximation with gradient corrections up to N 3LO [1], the nuclear mean-field is local and contains derivative operators up to sixth order. The locality allows for an effective and fast solution of the self-consistent equations. Solution method: The program uses the spherical harmonic oscillator basis to expand single-particle wave functions of neutrons and protons for the nuclear state being described by the N 3LO nuclear energy density functional [1]. The expansion coefficients are determined by the iterative diagonalization of the mean-field Hamiltonian, which depends non
NASA Astrophysics Data System (ADS)
Katsuki, Hiroyuki; Ohmori, Kenzo; Horie, Toru; Yanagi, Hisao; Ohmori, Kenji
2015-09-01
Solid parahydrogen, which is known to have an exceptionally long vibrational coherence lifetime as a molecular solid, offers an ideal testbed to perform coherent control experiments in the condensed phase. Here we demonstrate the spatial manipulation and visualization of the relative phase of vibrational wave functions in solid parahydrogen. Spatial distribution of vibrational excitation is generated by femtosecond impulsive Raman excitation. It is shown that the imprinted initial phase can be manipulated by wave-front modulation of the excitation laser pulses with a spatial light modulator. An interferometric measurement is used to convert the spatial phase distribution of the vibrational wave functions to the amplitude distribution. We have confirmed that the spatial profile of the scattered anti-Stokes pulse reveals the spatial phase distribution of the wave functions. The read-and-write scheme demonstrated in this experiment is applicable to a broad range of Raman memory systems accessible by Λ -type transitions.
Jung, Hea-Jin; Tatar, Angelica; Tu, Yiping; Nobumori, Chika; Yang, Shao H; Goulbourne, Chris N; Herrmann, Harald; Fong, Loren G; Young, Stephen G
2014-12-01
B-type lamins (lamins B1 and B2) have been considered to be essential for many crucial functions in the cell nucleus (e.g., DNA replication and mitotic spindle formation). However, this view has been challenged by the observation that an absence of both B-type lamins in keratinocytes had no effect on cell proliferation or the development of skin and hair. The latter findings raised the possibility that the functions of B-type lamins are subserved by lamins A and C. To explore that idea, we created mice lacking all nuclear lamins in keratinocytes. Those mice developed ichthyosis and a skin barrier defect, which led to death from dehydration within a few days after birth. Microscopy of nuclear-lamin-deficient skin revealed hyperkeratosis and a disordered stratum corneum with an accumulation of neutral lipid droplets; however, BrdU incorporation into keratinocytes was normal. Skin grafting experiments confirmed the stratum corneum abnormalities and normal BrdU uptake. Interestingly, the absence of nuclear lamins in keratinocytes resulted in an interspersion of nuclear/endoplasmic reticulum membranes with the chromatin. Thus, a key function of the nuclear lamina is to serve as a "fence" and prevent the incursion of cytoplasmic organelles into the nuclear chromatin. PMID:25312645
Jung, Hea-Jin; Tatar, Angelica; Tu, Yiping; Nobumori, Chika; Yang, Shao H.; Goulbourne, Chris N.; Herrmann, Harald
2014-01-01
B-type lamins (lamins B1 and B2) have been considered to be essential for many crucial functions in the cell nucleus (e.g., DNA replication and mitotic spindle formation). However, this view has been challenged by the observation that an absence of both B-type lamins in keratinocytes had no effect on cell proliferation or the development of skin and hair. The latter findings raised the possibility that the functions of B-type lamins are subserved by lamins A and C. To explore that idea, we created mice lacking all nuclear lamins in keratinocytes. Those mice developed ichthyosis and a skin barrier defect, which led to death from dehydration within a few days after birth. Microscopy of nuclear-lamin-deficient skin revealed hyperkeratosis and a disordered stratum corneum with an accumulation of neutral lipid droplets; however, BrdU incorporation into keratinocytes was normal. Skin grafting experiments confirmed the stratum corneum abnormalities and normal BrdU uptake. Interestingly, the absence of nuclear lamins in keratinocytes resulted in an interspersion of nuclear/endoplasmic reticulum membranes with the chromatin. Thus, a key function of the nuclear lamina is to serve as a “fence” and prevent the incursion of cytoplasmic organelles into the nuclear chromatin. PMID:25312645
DNA--a molecule in search of additional functions: recipient of pool wave emissions? A hypothesis.
Doerfler, Walter
2010-09-01
Almost the entire nucleotide sequence of human DNA is functionally unaccounted for, although large parts of the human genome are transcribed. The genes, as defined by current molecular biology, comprise about 1.5-2% of the DNA molecule. It is proposed that DNA encodes additional, hitherto unrecognized functions. In this discussion, the total information inside and outside the universe we live in is termed the pool or the sum total, known or unknown, of all laws, matter, energy, concepts and events. In a hypothetical model, a Gedankenexperiment, it is suggested that the total of all information emits pool waves of an unknown physical nature. They could be related to black energy or have completely different qualities. The designation pool waves should not imply any similarity to electromagnetism. Further, DNA is suggested to have the capability of interacting with the pool waves and thus permit humans - to some partly genetically determined and yet very limited extent - to perceive information from the pool. Pool emissions might be one of the forces that have been instrumental in and are still driving evolution from simple oligonucleotides to DNA with ever more complex recipient capacities. It will be a major challenge for researchers in the field to unravel these and less hypothetical undetected coding principles in DNA. It is uncertain whether the current trend to search the available DNA sequences with ever more refined computer technology on the basis of our present understanding of biology will detect unknown coding systems. For molecular medicine, research into the genetics of the most common human diseases could profit from the elucidation of presently still ephemeral codes in human DNA. Young scientists with a proven record of original research deserve support for the pursuit of unconventional ideas. This concept of granting priorities will be of the utmost importance in advancing the field beyond current concepts in molecular biology. PMID:20356684
System and Method for Measuring the Transfer Function of a Guided Wave Device
NASA Technical Reports Server (NTRS)
Froggatt, Mark E. (Inventor); Erdogan, Turan (Inventor)
2002-01-01
A method/system are provided for measuring the NxN scalar transfer function elements for an N-port guided wave device. Optical energy of a selected wavelength is generated at a source and directed along N reference optical paths having N reference path lengths. Each reference optical path terminates in one of N detectors such that N reference signals are produced at the N detectors. The reference signals are indicative of amplitude, phase and frequency of the optical energy carried along the N reference optical paths. The optical energy from the source is also directed to the N-ports of the guided wave device and then on to each of the N detectors such that N measurement optical paths are defined between the source and each of the N detectors. A portion of the optical energy is modified in terms of at least one of the amplitude and phase to produce N modified signals at each of the N detectors. At each of the N detectors, each of the N modified signals is combined with a corresponding one of the N reference signals to produce corresponding N combined signals at each of the N detectors. A total of N(sup 2) measurement signals are generated by the N detectors. Each of the N(sup 2) measurement signals is sampled at a wave number increment (Delta)k so that N(sup 2) sampled signals are produced. The NxN transfer function elements are generated using the N(sup 2) sampled signals. Reference and measurement path length constraints are defined such that the N combined signals at each of the N detectors are spatially separated from one another in the time domain.
NASA Astrophysics Data System (ADS)
Chamel, N.; Fantina, A. F.; Pearson, J. M.; Goriely, S.
2016-01-01
We study the constraints imposed by nuclear mass measurements and neutron-star observations on the symmetry energy. For this purpose, we use a family of unified equations of state of neutron-star interiors, based on generalised Skyrme functionals that were fitted to essentially all the experimental nuclear mass data while ensuring a realistic neutron-matter equation of state.
Testing for parity violation in nuclei using spin density matrices for nuclear density functionals
NASA Astrophysics Data System (ADS)
Barrett, B. R.; Giraud, B. G.
2015-06-01
The spin density matrix (SDM) used in atomic and molecular physics is revisited for nuclear physics, in the context of the radial density functional theory. The vector part of the SDM defines a ‘hedgehog’ situation, which exists only if nuclear states contain some amount of parity violation. A toy model is given as an illustrative example.
Lee, Kayoung; Goh, Grace Ying Shyen; Wong, Marcus Andrew; Klassen, Tara Leah; Taubert, Stefan
2016-01-01
Nuclear hormone receptors (NHRs) are transcription factors that regulate numerous physiological and developmental processes and represent important drug targets. NHR-49, an ortholog of Hepatocyte Nuclear Factor 4 (HNF4), has emerged as a key regulator of lipid metabolism and life span in the nematode worm Caenorhabditis elegans. However, many aspects of NHR-49 function remain poorly understood, including whether and how it regulates individual sets of target genes and whether its activity is modulated by a ligand. A recent study identified three gain-of-function (gof) missense mutations in nhr-49 (nhr-49(et7), nhr-49(et8), and nhr-49(et13), respectively). These substitutions all affect the ligand-binding domain (LBD), which is critical for ligand binding and protein interactions. Thus, these alleles provide an opportunity to test how three specific residues contribute to NHR-49 dependent gene regulation. We used computational and molecular methods to delineate how these mutations alter NHR-49 activity. We find that despite originating from a screen favoring the activation of specific NHR-49 targets, all three gof alleles cause broad upregulation of NHR-49 regulated genes. Interestingly, nhr-49(et7) and nhr-49(et8) exclusively affect nhr-49 dependent activation, whereas the nhr-49(et13) surprisingly affects both nhr-49 mediated activation and repression, implicating the affected residue as dually important. We also observed phenotypic non-equivalence of these alleles, as they unexpectedly caused a long, short, and normal life span, respectively. Mechanistically, the gof substitutions altered neither protein interactions with the repressive partner NHR-66 and the coactivator MDT-15 nor the subcellular localization or expression of NHR-49. However, in silico structural modeling revealed that NHR-49 likely interacts with small molecule ligands and that the missense mutations might alter ligand binding, providing a possible explanation for increased NHR-49 activity. In
Khan, Shehryar; Kubica-Misztal, Aleksandra; Kruk, Danuta; Kowalewski, Jozef; Odelius, Michael
2015-01-21
The zero-field splitting (ZFS) of the electronic ground state in paramagnetic ions is a sensitive probe of the variations in the electronic and molecular structure with an impact on fields ranging from fundamental physical chemistry to medical applications. A detailed analysis of the ZFS in a series of symmetric Gd(III) complexes is presented in order to establish the applicability and accuracy of computational methods using multiconfigurational complete-active-space self-consistent field wave functions and of density functional theory calculations. The various computational schemes are then applied to larger complexes Gd(III)DOTA(H2O)(-), Gd(III)DTPA(H2O)(2-), and Gd(III)(H2O)8(3+) in order to analyze how the theoretical results compare to experimentally derived parameters. In contrast to approximations based on density functional theory, the multiconfigurational methods produce results for the ZFS of Gd(III) complexes on the correct order of magnitude. PMID:25612706
Khan, Shehryar Odelius, Michael; Kubica-Misztal, Aleksandra; Kruk, Danuta; Kowalewski, Jozef
2015-01-21
The zero-field splitting (ZFS) of the electronic ground state in paramagnetic ions is a sensitive probe of the variations in the electronic and molecular structure with an impact on fields ranging from fundamental physical chemistry to medical applications. A detailed analysis of the ZFS in a series of symmetric Gd(III) complexes is presented in order to establish the applicability and accuracy of computational methods using multiconfigurational complete-active-space self-consistent field wave functions and of density functional theory calculations. The various computational schemes are then applied to larger complexes Gd(III)DOTA(H{sub 2}O){sup −}, Gd(III)DTPA(H{sub 2}O){sup 2−}, and Gd(III)(H{sub 2}O){sub 8}{sup 3+} in order to analyze how the theoretical results compare to experimentally derived parameters. In contrast to approximations based on density functional theory, the multiconfigurational methods produce results for the ZFS of Gd(III) complexes on the correct order of magnitude.
Ergodicity breaking and wave-function statistics in disordered interacting systems
De Luca, Andrea
2014-08-20
We present the study of the structure of many-body eigenfunctions in a one-dimensional disordered spin chain. We discuss the choice of an appropriate basis in the Hilbert space, where the problem can be seen as an Anderson model defined on a high-dimensional non-trivial graph, determined by the many-body Hamiltonian. The comparison with the usual behavior of wave-functions in finite dimensional Anderson localization allows us to put in light the main differences of the many-body case. At high disorder, the typical eigenfunctions do not seem to localize though they occupy a infinitesimal portion of the Hilbert space in the thermodynamic limit. We perform a detailed analysis of the distribution of the wave-function coefficients and their peculiar scaling in the small and large disorder phase. We propose a criterion to identify the position of the transition by looking at the long tails of these distributions. The results coming from exact diagonalization show signs of breaking of ergodicity when the disorder reaches a critical value that agrees with the estimation of the many-body localization transition in the same model.
Crustal Structure of Iraq from Receiver Functions and Surface Wave Dispersion
Gok, R; Mahdi, H; Al-Shukri, H; Rodgers, A J
2006-08-31
We report the crustal structure of Iraq, located in the northeastern Arabian plate, estimated by joint inversion of P-wave receiver functions and surface wave group velocity dispersion. Receiver functions were computed from teleseismic recordings at two temporary broadband seismic stations in Mosul (MSL) and Baghdad (BHD), separated by approximately 360 km. Group velocity dispersion curves at the sites were derived from continental-scale tomography of Pasyanos (2006). The inversion results show that the crustal thicknesses are 39 km at MSL and 43 km at BHD. Both sites reveal low velocity surface layers consistent with sedimentary thickness of about 3 km at station MSL and 7 km at BHD, agreeing well with the existing models. Ignoring the sediments, the crustal velocities and thicknesses are remarkably similar between the two stations, suggesting that the crustal structure of the proto-Arabian Platform in northern Iraq was uniform before subsidence and deposition of the sediments in the Cenozoic. Deeper low velocity sediments at BHD are expected to result in higher ground motions for earthquakes.
Is a system's wave function in one-to-one correspondence with its elements of reality?
Colbeck, Roger; Renner, Renato
2012-04-13
Although quantum mechanics is one of our most successful physical theories, there has been a long-standing debate about the interpretation of the wave function--the central object of the theory. Two prominent views are that (i) it corresponds to an element of reality, i.e., an objective attribute that exists before measurement, and (ii) it is a subjective state of knowledge about some underlying reality. A recent result [M. F. Pusey, J. Barrett, and T. Rudolph, arXiv:1111.3328] has placed the subjective interpretation into doubt, showing that it would contradict certain physically plausible assumptions, in particular, that multiple systems can be prepared such that their elements of reality are uncorrelated. Here we show, based only on the assumption that measurement settings can be chosen freely, that a system's wave function is in one-to-one correspondence with its elements of reality. This also eliminates the possibility that it can be interpreted subjectively. PMID:22587234
NASA Astrophysics Data System (ADS)
Luo, Hongjun; Kolb, Dietmar; Flad, Heinz-Jurgen; Hackbusch, Wolfgang; Koprucki, Thomas
2002-08-01
We have studied various aspects concerning the use of hyperbolic wavelets and adaptive approximation schemes for wavelet expansions of correlated wave functions. In order to analyze the consequences of reduced regularity of the wave function at the electron-electron cusp, we first considered a realistic exactly solvable many-particle model in one dimension. Convergence rates of wavelet expansions, with respect to L2 and H1 norms and the energy, were established for this model. We compare the performance of hyperbolic wavelets and their extensions through adaptive refinement in the cusp region, to a fully adaptive treatment based on the energy contribution of individual wavelets. Although hyperbolic wavelets show an inferior convergence behavior, they can be easily refined in the cusp region yielding an optimal convergence rate for the energy. Preliminary results for the helium atom are presented, which demonstrate the transferability of our observations to more realistic systems. We propose a contraction scheme for wavelets in the cusp region, which reduces the number of degrees of freedom and yields a favorable cost to benefit ratio for the evaluation of matrix elements.
Niels Bohr on the wave function and the classical/quantum divide
NASA Astrophysics Data System (ADS)
Zinkernagel, Henrik
2016-02-01
It is well known that Niels Bohr insisted on the necessity of classical concepts in the account of quantum phenomena. But there is little consensus concerning his reasons, and what he exactly meant by this. In this paper, I re-examine Bohr's interpretation of quantum mechanics, and argue that the necessity of the classical can be seen as part of his response to the measurement problem. More generally, I attempt to clarify Bohr's view on the classical/quantum divide, arguing that the relation between the two theories is that of mutual dependence. An important element in this clarification consists in distinguishing Bohr's idea of the wave function as symbolic from both a purely epistemic and an ontological interpretation. Together with new evidence concerning Bohr's conception of the wave function collapse, this sets his interpretation apart from both standard versions of the Copenhagen interpretation, and from some of the reconstructions of his view found in the literature. I conclude with a few remarks on how Bohr's ideas make much sense also when modern developments in quantum gravity and early universe cosmology are taken into account.
Gutzwiller wave function for finite systems: superconductivity in the Hubbard model
NASA Astrophysics Data System (ADS)
Tomski, Andrzej; Kaczmarczyk, Jan
2016-05-01
We study the superconducting phase of the Hubbard model using the Gutzwiller variational wave function (GWF) and the recently proposed diagrammatic expansion technique (DE-GWF). The DE-GWF method works on the level of the full GWF and in the thermodynamic limit. Here, we consider a finite-size system to study the accuracy of the results as a function of the system size (which is practically unrestricted). We show that the finite-size scaling used, e.g. in the variational Monte Carlo method can lead to significant, uncontrolled errors. The presented research is the first step towards applying the DE-GWF method in studies of inhomogeneous situations, including systems with impurities, defects, inhomogeneous phases, or disorder.
Gutzwiller wave function for finite systems: superconductivity in the Hubbard model.
Tomski, Andrzej; Kaczmarczyk, Jan
2016-05-01
We study the superconducting phase of the Hubbard model using the Gutzwiller variational wave function (GWF) and the recently proposed diagrammatic expansion technique (DE-GWF). The DE-GWF method works on the level of the full GWF and in the thermodynamic limit. Here, we consider a finite-size system to study the accuracy of the results as a function of the system size (which is practically unrestricted). We show that the finite-size scaling used, e.g. in the variational Monte Carlo method can lead to significant, uncontrolled errors. The presented research is the first step towards applying the DE-GWF method in studies of inhomogeneous situations, including systems with impurities, defects, inhomogeneous phases, or disorder. PMID:27023047
NASA Astrophysics Data System (ADS)
Stoyanov, B. J.; Farrell, R. A.
1996-02-01
The Schwinger variational principle for the scattering amplitude is applied to two related test problems: an infinitely long perfectly conducting circular cylinder and a hemicylindrically embossed plane illuminated by a normally incident plane wave whose magnetic field is perpendicular to the cylinder axis (TM polarization). It is demonstrated that the variational principle yields very good results with trial functions containing only a few variational parameters, provided the trial functions mimic not only the correct boundary conditions on the scatterer surface but also the expected shadowing effects of the obstacle. A variety of analytical variational limits for both low and high frequencies are derived, which, together with the numerical results for intermediate frequencies, compare very favorably with the available exact solutions.
NASA Astrophysics Data System (ADS)
Liu, Tianshi; Feng, Xi; Zhang, Haiming
2016-08-01
To obtain the synthetic seismogram using the Cagniard-de Hoop method, one needs to calculate the integral over slowness. When the source is shallow and the slowness is near the zero of the Rayleigh function, the integrand behaves like a sharp pulse. In this study, we attempt to study this pulse with an asymptotic approach, and conclude that the Rayleigh wave in the time domain originates from this pulse in the slowness domain. We therefore offer an explanation of the excitation of the Rayleigh wave in a mathematical point of view. In addition, we propose a method to improve the efficiency of the numerical quadrature in the calculation of the synthetic seismogram.
NASA Astrophysics Data System (ADS)
Liu, Tianshi; Feng, Xi; Zhang, Haiming
2016-06-01
To obtain the synthetic seismogram using the Cagniard-de Hoop method, one needs to calculate the integral over slowness. When the source is shallow and the slowness is near the zero of the Rayleigh function, the integrand behaves like a sharp pulse. In this study, we attempt to study this pulse with an asymptotic approach, and conclude that the Rayleigh wave in the time domain originates from this pulse in the slowness domain. We therefore offer an explanation of the excitation of the Rayleigh wave in a mathematical point of view. In addition, we propose a method to improve the efficiency of the numerical quadrature in the calculation of the synthetic seismogram.
Franck-Condon factors based on anharmonic vibrational wave functions of polyatomic molecules
NASA Astrophysics Data System (ADS)
Rodriguez-Garcia, Valerie; Yagi, Kiyoshi; Hirao, Kimihiko; Iwata, Suehiro; Hirata, So
2006-07-01
Franck-Condon (FC) integrals of polyatomic molecules are computed on the basis of vibrational self-consistent-field (VSCF) or configuration-interaction (VCI) calculations capable of including vibrational anharmonicity to any desired extent (within certain molecular size limits). The anharmonic vibrational wave functions of the initial and final states are expanded unambiguously by harmonic oscillator basis functions of normal coordinates of the respective electronic states. The anharmonic FC integrals are then obtained as linear combinations of harmonic counterparts, which can, in turn, be evaluated by established techniques taking account of the Duschinsky rotations, geometry displacements, and frequency changes. Alternatively, anharmonic wave functions of both states are expanded by basis functions of just one electronic state, permitting the FC integral to be evaluated directly by the Gauss-Hermite quadrature used in the VSCF and VCI steps [Bowman et al., Mol. Phys. 104, 33 (2006)]. These methods in conjunction with the VCI and coupled-cluster with singles, doubles, and perturbative triples [CCSD(T)] method have predicted the peak positions and intensities of the vibrational manifold in the X˜B12 photoelectron band of H2O with quantitative accuracy. It has revealed that two weakly visible peaks are the result of intensity borrowing from nearby states through anharmonic couplings, an effect explained qualitatively by VSCF and quantitatively by VCI, but not by the harmonic approximation. The X˜B22 photoelectron band of H2CO is less accurately reproduced by this method, likely because of the inability of CCSD(T)/cc-pVTZ to describe the potential energy surface of open-shell H2CO+ with the same high accuracy as in H2O+.
NASA Astrophysics Data System (ADS)
Sicilia, E.; de Luca, G.; Chiodo, S.; Russo, N.; Calaminici, P.; Koster, A. M.; Jug, K.
Density functional calculations of the electric field gradient tensor at the nitrogen nucleus in 13 test molecules, containing 14 nitrogen sites, have been performed using the linear combination of Gaussian-type orbital Kohn-Sham density functional theory (LCGTO-KSDFT) approach. Local and gradient corrected functionals were used for all-electron calculations. All the molecular structures were optimized at their respective levels of theory with extended basis sets. Calibrated 14N nuclear quadrupole moments were obtained through a fitting procedure between calculated electric field gradients and experimental nuclear quadrupole coupling constants of the test set of molecules for each basis set and functional considered. With these calibrated 14N nuclear quadrupole moments, the nuclear quadrupole coupling constants of the following selected systems were determined: fluoromethylisonitrile, pyridine, pyrrole, imadazole, pyrazole, 1,8-bis(dimethyl-amino)naphthalene, cyclotetramethylenetetranitramine, cocaine and heroin.
NASA Astrophysics Data System (ADS)
Palomeras, I.; Thurner, S.; Levander, A.; Humphreys, E.; Miller, M. S.; Carbonell, R.; Gallart, J.
2012-04-01
The western Mediterranean is a diffuse plate boundary separating the African and Eurasian plates. Cenozoic deformation is centered on the Gibraltar arc and Alboran Sea, and occupies a wide area from the southern Iberian Massif in Spain to the Atlas Mountains in Morocco. We present a model of the lithospheric structure of this region derived from Rayleigh wave tomography and Ps receiver functions, using data from the PICASSO (Program to Investigate Convective Alboran Sea System Overturn) linear broadband array of ~100 seismographs. This array is deployed from central Spain to the Morocco-Algerian border. We complement these data with some of that recorded by IberArray, an areal broadband array, operated by the Spanish seismological community, covering the same region with a uniform 50 km x 50 km grid of stations. Rayleigh phase velocities have been measured from 20-167s period using the two-plane-wave method to remove complications due to multi-pathing, and finite-frequency kernels to improve lateral resolution. The phase velocities were inverted for 1D structure on a 0.25 by 0.25 degree grid. Ps receiver functions at 1Hz and 2Hz were calculated for the same area using water-level and time-domain iterative deconvolution, and were then CCP stacked. The Rayleigh wave shear velocity model, jointly interpreted with the discontinuity structure from the CCP stack, shows the first-order lithospheric structure, and the lithosphere-asthenosphere boundary (LAB). From north to south along the PICASSO profile: The lithosphere is ~120 km thick beneath the Iberian Massif, where it has the highest shear velocity, 4.45 km/s. To the south the lithosphere thins dramatically beneath the Betic Mountains to ~85 km, and then varies in thickness and decreases in velocity beneath the Alboran Sea and Gibraltar Arc. The thinnest lithosphere, ~60 km, is observed beneath the Rif mountains and Middle Atlas, with a low velocity feature (4.2 km/s) at ~60 km depth beneath a site of Late Cenozoic
NASA Astrophysics Data System (ADS)
Restrepo, Doriam; Gómez, Juan David; Jaramillo, Juan Diego
2014-09-01
We present a closed-form frequency-wave number ( ω - k) Green's function for a layered, elastic half-space under SH wave propagation. It is shown that for every ( ω - k) pair, the fundamental solution exhibits two distinctive features: (1) the original layered system can be reduced to a system composed by the uppermost superficial layer over an equivalent half-space; (2) the fundamental solution can be partitioned into three different fundamental solutions, each one carrying out a different physical interpretation, i.e., an equivalent half-space, source image impact, and dispersive wave effect, respectively. Such an interpretation allows the proper use of analytical and numerical integration schemes, and ensures the correct assessment of Cauchy principal value integrals. Our method is based upon a stiffness-matrix scheme, and as a first approach we assume that observation points and the impulsive SH line-source are spatially located within the uppermost superficial layer. We use a discrete wave number boundary element strategy to test the benefits of our fundamental solution. We benchmark our results against reported solutions for an infinitely long circular canyon subjected to oblique incident SH waves within a homogeneous half-space. Our results show an almost exact agreement with previous studies. We further shed light on the impact of horizontal strata by examining the dynamic response of the circular canyon to oblique incident SH waves under different layered half-space configurations and incident angles. Our results show that modifications in the layering structure manifest by larger peak ground responses, and stronger spatial variability due to interactions of the canyon geometry with trapped Love waves in combination with impedance contrast effects.
Giesbertz, Klaas J. H.; Leeuwen, Robert van
2014-05-14
Electron correlations in molecules can be divided in short range dynamical correlations, long range Van der Waals type interactions, and near degeneracy static correlations. In this work, we analyze for a one-dimensional model of a two-electron system how these three types of correlations can be incorporated in a simple wave function of restricted functional form consisting of an orbital product multiplied by a single correlation function f (r{sub 12}) depending on the interelectronic distance r{sub 12}. Since the three types of correlations mentioned lead to different signatures in terms of the natural orbital (NO) amplitudes in two-electron systems, we make an analysis of the wave function in terms of the NO amplitudes for a model system of a diatomic molecule. In our numerical implementation, we fully optimize the orbitals and the correlation function on a spatial grid without restrictions on their functional form. Due to this particular form of the wave function, we can prove that none of the amplitudes vanishes and moreover that it displays a distinct sign pattern and a series of avoided crossings as a function of the bond distance in agreement with the exact solution. This shows that the wave function ansatz correctly incorporates the long range Van der Waals interactions. We further show that the approximate wave function gives an excellent binding curve and is able to describe static correlations. We show that in order to do this the correlation function f (r{sub 12}) needs to diverge for large r{sub 12} at large internuclear distances while for shorter bond distances it increases as a function of r{sub 12} to a maximum value after which it decays exponentially. We further give a physical interpretation of this behavior.
Nuclear density functional theory with a semi-contact 3-body interaction
NASA Astrophysics Data System (ADS)
Lacroix, Denis; Bennaceur, Karim
2016-01-01
Theories combining nuclear density functional approach (DFT) and effects beyond the independent particle/quasi-particle limit have attracted much attention recently. In particular, such theories, generically referred as "beyond mean-field" (BMF) seem unavoidable to account for both single-particle effects and complex quantum internal phenomena in nuclear finite many-body nuclear systems. It has been realized recently that BMF theories might lead to specific difficulties when applied within the nuclear DFT context. An example is the appearance of divergences in configuration mixing approaches. A short summary of the difficulties is given here. One source of problem is the use of energy functional of non-integer powers of the density. We show that such dependence can be mimicked by a suitable choice of a three-body interaction. Application on infinite nuclear matter in various spin-isospin channels will be given.
Bateman, Nicholas W; Shoji, Yutaka; Conrads, Kelly A; Stroop, Kevin D; Hamilton, Chad A; Darcy, Kathleen M; Maxwell, George L; Risinger, John I; Conrads, Thomas P
2016-01-01
AT-rich interactive domain-containing protein 1A (ARID1A) is a recently identified nuclear tumor suppressor frequently altered in solid tumor malignancies. We have identified a bipartite-like nuclear localization sequence (NLS) that contributes to nuclear import of ARID1A not previously described. We functionally confirm activity using GFP constructs fused with wild-type or mutant NLS sequences. We further show that cyto-nuclear localized, bipartite NLS mutant ARID1A exhibits greater stability than nuclear-localized, wild-type ARID1A. Identification of this undescribed functional NLS within ARID1A contributes vital insights to rationalize the impact of ARID1A missense mutations observed in patient tumors. PMID:26614907
Two-state model based on the block-localized wave function method.
Mo, Yirong
2007-06-14
The block-localized wave function (BLW) method is a variant of ab initio valence bond method but retains the efficiency of molecular orbital methods. It can derive the wave function for a diabatic (resonance) state self-consistently and is available at the Hartree-Fock (HF) and density functional theory (DFT) levels. In this work we present a two-state model based on the BLW method. Although numerous empirical and semiempirical two-state models, such as the Marcus-Hush two-state model, have been proposed to describe a chemical reaction process, the advantage of this BLW-based two-state model is that no empirical parameter is required. Important quantities such as the electronic coupling energy, structural weights of two diabatic states, and excitation energy can be uniquely derived from the energies of two diabatic states and the adiabatic state at the same HF or DFT level. Two simple examples of formamide and thioformamide in the gas phase and aqueous solution were presented and discussed. The solvation of formamide and thioformamide was studied with the combined ab initio quantum mechanical and molecular mechanical Monte Carlo simulations, together with the BLW-DFT calculations and analyses. Due to the favorable solute-solvent electrostatic interaction, the contribution of the ionic resonance structure to the ground state of formamide and thioformamide significantly increases, and for thioformamide the ionic form is even more stable than the covalent form. Thus, thioformamide in aqueous solution is essentially ionic rather than covalent. Although our two-state model in general underestimates the electronic excitation energies, it can predict relative solvatochromic shifts well. For instance, the intense pi-->pi* transition for formamide upon solvation undergoes a redshift of 0.3 eV, compared with the experimental data (0.40-0.5 eV). PMID:17581041
Crustal structure beneath western and eastern Iceland from surface waves and receiver functions
Du, Z.; Foulger, G.R.; Julian, B.R.; Allen, R.M.; Nolet, G.; Morgan, W.J.; Bergsson, B.H.; Erlendsson, P.; Jakobsdottir, S.; Ragnarsson, S.; Stefansson, R.; Vogfjord, K.
2002-01-01
We determine the crustal structures beneath 14 broad-band seismic stations, deployed in western, eastern, central and southern Iceland, using surface wave dispersion curves and receiver functions. We implement a method to invert receiver functions using constraints obtained from genetic algorithm inversion of surface waves. Our final models satisfy both data sets. The thickness of the upper crust, as defined by the velocity horizon Vs = 3.7 km s-1, is fairly uniform at ???6.5-9 km beneath the Tertiary intraplate areas of western and eastern Iceland, and unusually thick at 11 km beneath station HOT22 in the far south of Iceland. The depth to the base of the lower crust, as defined by the velocity horizon Vs = 4.1 km s-1 is ???20-26 km in western Iceland and ???27-33 km in eastern Iceland. These results agree with those of explosion profiles that detect a thinner crust beneath western Iceland than beneath eastern Iceland. An earlier report of a substantial low-velocity zone beneath the Middle Volcanic Zone in the lower crust is confirmed by a similar observation beneath an additional station there. As was found in previous receiver function studies, the most reliable feature of the results is the clear division into an upper sequence that is a few kilometres thick where velocity gradients are high, and a lower, thicker sequence where velocity gradients are low. The transition to typical mantle velocities is variable, and may range from being very gradational to being relatively sharp and clear. A clear Moho, by any definition, is rarely seen, and there is thus uncertainty in estimates of the thickness of the crust in many areas. Although a great deal of seismic data are now available constraining the structures of the crust and upper mantle beneath Iceland, their geological nature is not well understood.
Orbital-free density functional theory implementation with the projector augmented-wave method
NASA Astrophysics Data System (ADS)
Lehtomäki, Jouko; Makkonen, Ilja; Caro, Miguel A.; Harju, Ari; Lopez-Acevedo, Olga
2014-12-01
We present a computational scheme for orbital-free density functional theory (OFDFT) that simultaneously provides access to all-electron values and preserves the OFDFT linear scaling as a function of the system size. Using the projector augmented-wave method (PAW) in combination with real-space methods, we overcome some obstacles faced by other available implementation schemes. Specifically, the advantages of using the PAW method are twofold. First, PAW reproduces all-electron values offering freedom in adjusting the convergence parameters and the atomic setups allow tuning the numerical accuracy per element. Second, PAW can provide a solution to some of the convergence problems exhibited in other OFDFT implementations based on Kohn-Sham (KS) codes. Using PAW and real-space methods, our orbital-free results agree with the reference all-electron values with a mean absolute error of 10 meV and the number of iterations required by the self-consistent cycle is comparable to the KS method. The comparison of all-electron and pseudopotential bulk modulus and lattice constant reveal an enormous difference, demonstrating that in order to assess the performance of OFDFT functionals it is necessary to use implementations that obtain all-electron values. The proposed combination of methods is the most promising route currently available. We finally show that a parametrized kinetic energy functional can give lattice constants and bulk moduli comparable in accuracy to those obtained by the KS PBE method, exemplified with the case of diamond.
Orbital-free density functional theory implementation with the projector augmented-wave method
Lehtomäki, Jouko; Makkonen, Ilja; Harju, Ari; Lopez-Acevedo, Olga; Caro, Miguel A.
2014-12-21
We present a computational scheme for orbital-free density functional theory (OFDFT) that simultaneously provides access to all-electron values and preserves the OFDFT linear scaling as a function of the system size. Using the projector augmented-wave method (PAW) in combination with real-space methods, we overcome some obstacles faced by other available implementation schemes. Specifically, the advantages of using the PAW method are twofold. First, PAW reproduces all-electron values offering freedom in adjusting the convergence parameters and the atomic setups allow tuning the numerical accuracy per element. Second, PAW can provide a solution to some of the convergence problems exhibited in other OFDFT implementations based on Kohn-Sham (KS) codes. Using PAW and real-space methods, our orbital-free results agree with the reference all-electron values with a mean absolute error of 10 meV and the number of iterations required by the self-consistent cycle is comparable to the KS method. The comparison of all-electron and pseudopotential bulk modulus and lattice constant reveal an enormous difference, demonstrating that in order to assess the performance of OFDFT functionals it is necessary to use implementations that obtain all-electron values. The proposed combination of methods is the most promising route currently available. We finally show that a parametrized kinetic energy functional can give lattice constants and bulk moduli comparable in accuracy to those obtained by the KS PBE method, exemplified with the case of diamond.
Construction of exchange repulsion in terms of the wave functions at QM/MM boundary region
Takahashi, Hideaki Umino, Satoru; Morita, Akihiro
2015-08-28
We developed a simple method to calculate exchange repulsion between a quantum mechanical (QM) solute and a molecular mechanical (MM) molecule in the QM/MM approach. In our method, the size parameter in the Buckingham type potential for the QM solute is directly determined in terms of the one-electron wave functions of the solute. The point of the method lies in the introduction of the exchange core function (ECF) defined as a Slater function which mimics the behavior of the exterior electron density at the QM/MM boundary region. In the present paper, the ECF was constructed in terms of the Becke-Roussel (BR) exchange hole function. It was demonstrated that the ECF yielded by the BR procedure can faithfully reproduce the radial behavior of the electron density of a QM solute. The size parameter of the solute as well as the exchange repulsion are, then, obtained using the overlap model without any fitting procedure. To examine the efficiency of the method, it was applied to calculation of the exchange repulsions for minimal QM/MM systems, hydrogen-bonded water dimer, and H{sub 3}O{sup +}–H{sub 2}O. We found that our approach is able to reproduce the potential energy curves for these systems showing reasonable agreements with those given by accurate full quantum chemical calculations.
Construction of exchange repulsion in terms of the wave functions at QM/MM boundary region
NASA Astrophysics Data System (ADS)
Takahashi, Hideaki; Umino, Satoru; Morita, Akihiro
2015-08-01
We developed a simple method to calculate exchange repulsion between a quantum mechanical (QM) solute and a molecular mechanical (MM) molecule in the QM/MM approach. In our method, the size parameter in the Buckingham type potential for the QM solute is directly determined in terms of the one-electron wave functions of the solute. The point of the method lies in the introduction of the exchange core function (ECF) defined as a Slater function which mimics the behavior of the exterior electron density at the QM/MM boundary region. In the present paper, the ECF was constructed in terms of the Becke-Roussel (BR) exchange hole function. It was demonstrated that the ECF yielded by the BR procedure can faithfully reproduce the radial behavior of the electron density of a QM solute. The size parameter of the solute as well as the exchange repulsion are, then, obtained using the overlap model without any fitting procedure. To examine the efficiency of the method, it was applied to calculation of the exchange repulsions for minimal QM/MM systems, hydrogen-bonded water dimer, and H3O+-H2O. We found that our approach is able to reproduce the potential energy curves for these systems showing reasonable agreements with those given by accurate full quantum chemical calculations.
PML nuclear bodies: regulation, function and therapeutic perspectives.
Sahin, Umut; Lallemand-Breitenbach, Valérie; de Thé, Hugues
2014-11-01
PML nuclear bodies (NBs) were first described by electron microscopy and rediscovered through their treatment-reversible disruption in a rare leukaemia. They recruit multiple partner proteins and now emerge as interferon- and oxidative stress-responsive sumoylation factories. NBs mediate interferon-induced viral restriction, enhance proteolysis, finely tune metabolism and enforce stress-induced senescence. Apart from being markers of cellular stress, PML NBs could be harnessed pharmacologically in a number of conditions, including cancer, viral infection or neurodegenerative diseases. PMID:25138686
ABINIT: Plane-Wave-Based Density-Functional Theory on High Performance Computers
NASA Astrophysics Data System (ADS)
Torrent, Marc
2014-03-01
For several years, a continuous effort has been produced to adapt electronic structure codes based on Density-Functional Theory to the future computing architectures. Among these codes, ABINIT is based on a plane-wave description of the wave functions which allows to treat systems of any kind. Porting such a code on petascale architectures pose difficulties related to the many-body nature of the DFT equations. To improve the performances of ABINIT - especially for what concerns standard LDA/GGA ground-state and response-function calculations - several strategies have been followed: A full multi-level parallelisation MPI scheme has been implemented, exploiting all possible levels and distributing both computation and memory. It allows to increase the number of distributed processes and could not be achieved without a strong restructuring of the code. The core algorithm used to solve the eigen problem (``Locally Optimal Blocked Congugate Gradient''), a Blocked-Davidson-like algorithm, is based on a distribution of processes combining plane-waves and bands. In addition to the distributed memory parallelization, a full hybrid scheme has been implemented, using standard shared-memory directives (openMP/openACC) or porting some comsuming code sections to Graphics Processing Units (GPU). As no simple performance model exists, the complexity of use has been increased; the code efficiency strongly depends on the distribution of processes among the numerous levels. ABINIT is able to predict the performances of several process distributions and automatically choose the most favourable one. On the other hand, a big effort has been carried out to analyse the performances of the code on petascale architectures, showing which sections of codes have to be improved; they all are related to Matrix Algebra (diagonalisation, orthogonalisation). The different strategies employed to improve the code scalability will be described. They are based on an exploration of new diagonalization
Kurokawa, Yusaku I. E-mail: h.nakatsuji@qcri.or.jp; Nakashima, Hiroyuki; Nakatsuji, Hiroshi E-mail: h.nakatsuji@qcri.or.jp
2014-06-07
We derived the necessary conditions that must be satisfied by the non-relativistic time-independent exact wave functions for many-particle systems at a two-particle coalescence (or cusp) point. Some simple conditions are known to be Kato's cusp condition (CC) and Rassolov and Chipman's CC. In a previous study, we derived an infinite number of necessary conditions that two-particle wave functions must satisfy at a coalescence point. In the present study, we extend these conditions to many-particle systems. They are called general coalescence conditions (GCCs), and Kato's CC and Rassolov and Chipman's CC are included as special conditions. GCCs can be applied not only to Coulombic systems but also to any system in which the interaction between two particles is represented in a power series of inter-particle distances. We confirmed the correctness of our derivation of the GCCs by applying the exact wave function of a harmonium in electron-electron and electron-nucleus coalescence situations. In addition, we applied the free complement (FC) wave functions of a helium atom to the GCCs to examine the accuracy of the FC wave function in the context of a coalescence situation.
Kurokawa, Yusaku I; Nakashima, Hiroyuki; Nakatsuji, Hiroshi
2014-06-01
We derived the necessary conditions that must be satisfied by the non-relativistic time-independent exact wave functions for many-particle systems at a two-particle coalescence (or cusp) point. Some simple conditions are known to be Kato's cusp condition (CC) and Rassolov and Chipman's CC. In a previous study, we derived an infinite number of necessary conditions that two-particle wave functions must satisfy at a coalescence point. In the present study, we extend these conditions to many-particle systems. They are called general coalescence conditions (GCCs), and Kato's CC and Rassolov and Chipman's CC are included as special conditions. GCCs can be applied not only to Coulombic systems but also to any system in which the interaction between two particles is represented in a power series of inter-particle distances. We confirmed the correctness of our derivation of the GCCs by applying the exact wave function of a harmonium in electron-electron and electron-nucleus coalescence situations. In addition, we applied the free complement (FC) wave functions of a helium atom to the GCCs to examine the accuracy of the FC wave function in the context of a coalescence situation. PMID:24907986
SIRT6 deacetylates PKM2 to suppress its nuclear localization and oncogenic functions
Bhardwaj, Abhishek; Das, Sanjeev
2016-01-01
SIRT6 (sirtuin 6) is a member of sirtuin family of deacetylases involved in diverse processes including genome stability, metabolic homeostasis, and tumorigenesis. However, the role of SIRT6 deacetylase activity in its tumor-suppressor functions is not well understood. Here we report that SIRT6 binds to and deacetylates nuclear PKM2 (pyruvate kinase M2) at the lysine 433 residue. PKM2 is a glycolytic enzyme with nonmetabolic nuclear oncogenic functions. SIRT6-mediated deacetylation results in PKM2 nuclear export. We further have identified exportin 4 as the specific transporter mediating PKM2 nuclear export. As a result of SIRT6-mediated deacetylation, PKM2 nuclear protein kinase and transcriptional coactivator functions are abolished. Thus, SIRT6 suppresses PKM2 oncogenic functions, resulting in reduced cell proliferation, migration potential, and invasiveness. Furthermore, studies in mouse tumor models demonstrate that PKM2 deacetylation is integral to SIRT6-mediated tumor suppression and inhibition of metastasis. Additionally, reduced SIRT6 levels correlate with elevated nuclear acetylated PKM2 levels in increasing grades of hepatocellular carcinoma. These findings provide key insights into the pivotal role of deacetylase activity in SIRT6 tumor-suppressor functions. PMID:26787900
Capillary wave Hamiltonian for the Landau-Ginzburg-Wilson density functional.
Chacón, Enrique; Tarazona, Pedro
2016-06-22
We study the link between the density functional (DF) formalism and the capillary wave theory (CWT) for liquid surfaces, focused on the Landau-Ginzburg-Wilson (LGW) model, or square gradient DF expansion, with a symmetric double parabola free energy, which has been extensively used in theoretical studies of this problem. We show the equivalence between the non-local DF results of Parry and coworkers and the direct evaluation of the mean square fluctuations of the intrinsic surface, as is done in the intrinsic sampling method for computer simulations. The definition of effective wave-vector dependent surface tensions is reviewed and we obtain new proposals for the LGW model. The surface weight proposed by Blokhuis and the surface mode analysis proposed by Stecki provide consistent and optimal effective definitions for the extended CWT Hamiltonian associated to the DF model. A non-local, or coarse-grained, definition of the intrinsic surface provides the missing element to get the mesoscopic surface Hamiltonian from the molecular DF description, as had been proposed a long time ago by Dietrich and coworkers. PMID:27115912
Capillary wave Hamiltonian for the Landau–Ginzburg–Wilson density functional
NASA Astrophysics Data System (ADS)
Chacón, Enrique; Tarazona, Pedro
2016-06-01
We study the link between the density functional (DF) formalism and the capillary wave theory (CWT) for liquid surfaces, focused on the Landau–Ginzburg–Wilson (LGW) model, or square gradient DF expansion, with a symmetric double parabola free energy, which has been extensively used in theoretical studies of this problem. We show the equivalence between the non-local DF results of Parry and coworkers and the direct evaluation of the mean square fluctuations of the intrinsic surface, as is done in the intrinsic sampling method for computer simulations. The definition of effective wave-vector dependent surface tensions is reviewed and we obtain new proposals for the LGW model. The surface weight proposed by Blokhuis and the surface mode analysis proposed by Stecki provide consistent and optimal effective definitions for the extended CWT Hamiltonian associated to the DF model. A non-local, or coarse-grained, definition of the intrinsic surface provides the missing element to get the mesoscopic surface Hamiltonian from the molecular DF description, as had been proposed a long time ago by Dietrich and coworkers.
Scholkmann, Felix; Kleiser, Stefan; Metz, Andreas Jaakko; Zimmermann, Raphael; Mata Pavia, Juan; Wolf, Ursula; Wolf, Martin
2014-01-15
This year marks the 20th anniversary of functional near-infrared spectroscopy and imaging (fNIRS/fNIRI). As the vast majority of commercial instruments developed until now are based on continuous wave technology, the aim of this publication is to review the current state of instrumentation and methodology of continuous wave fNIRI. For this purpose we provide an overview of the commercially available instruments and address instrumental aspects such as light sources, detectors and sensor arrangements. Methodological aspects, algorithms to calculate the concentrations of oxy- and deoxyhemoglobin and approaches for data analysis are also reviewed. From the single-location measurements of the early years, instrumentation has progressed to imaging initially in two dimensions (topography) and then three (tomography). The methods of analysis have also changed tremendously, from the simple modified Beer-Lambert law to sophisticated image reconstruction and data analysis methods used today. Due to these advances, fNIRI has become a modality that is widely used in neuroscience research and several manufacturers provide commercial instrumentation. It seems likely that fNIRI will become a clinical tool in the foreseeable future, which will enable diagnosis in single subjects. PMID:23684868
Crustal shear-wave velocity structure beneath Sumatra from receiver function modeling
NASA Astrophysics Data System (ADS)
Bora, Dipok K.; Borah, Kajaljyoti; Goyal, Ayush
2016-05-01
We estimated the shear-wave velocity structure and Vp/Vs ratio of the crust beneath the Sumatra region by inverting stacked receiver functions from five three-component broadband seismic stations, located in diverse geologic setting, using a well known non-linear direct search approach, Neighborhood Algorithm (NA). Inversion results show significant variation of sediment layer thicknesses from 1 km beneath the backarc basin (station BKNI and PMBI) to 3-7 km beneath the coastal part of Sumatra region (station LHMI and MNAI) and Nias island (station GSI). Average sediment layer shear velocity (Vss) beneath all the stations is observed to be less (∼1.35 km/s) and their corresponding Vp/Vs ratio is very high (∼2.2-3.0). Crustal thickness beneath Sumatra region varies between 27 and 35 km, with exception of 19 km beneath Nias island, with average crustal Vs ∼3.1-3.4 km/s (Vp/Vs ∼1.8). It is well known that thick sediments with low Vs (and high Vp/Vs) amplify seismic waves even from a small-magnitude earthquake, which can cause huge damage in the zone. This study can provide the useful information of the crust for the Sumatra region. Since, Sumatra is an earthquake prone zone, which suffered the strong shaking of Great Andaman-Sumatra earthquake; this study can also be helpful for seismic hazard assessment.
NASA Technical Reports Server (NTRS)
Convery, P. D.; Schriver, D.; Ashour-Abdalla, M.; Richard, R. L.
2002-01-01
Nongyrotropic plasma distribution functions can be formed in regions of space where guiding center motion breaks down as a result of strongly curved and weak ambient magnetic fields. Such are the conditions near the current sheet in the Earth's middle and distant magnetotail, where observations of nongyrotropic ion distributions have been made. Here a systematic parameter study of nongyrotropic proton distributions using electromagnetic hybrid simulations is made. We model the observed nongyrotropic distributions by removing a number of arc length segments from a cold ring distribution and find significant differences with the results of simulations that initially have a gyrotropic ring distribution. Model nongyrotropic distributions with initially small perpendicular thermalization produce growing fluctuations that diffuse the ions into a stable Maxwellian-like distribution within a few proton gyro periods. The growing waves produced by nongyrotropic distributions are similar to the electromagnetic proton cyclotron waves produced by a gyrotropic proton ring distribution in that they propagate parallel to the background magnetic field and occur at frequencies on the order of the proton gyrofrequency, The maximum energy of the fluctuating magnetic field increases as the initial proton distribution is made more nongyrotropic, that is, more highly bunched in perpendicular velocity space. This increase can be as much as twice the energy produced in the gyrotropic case.
Scaling of plane-wave functions in statistically optimized near-field acoustic holography.
Hald, Jørgen
2014-11-01
Statistically Optimized Near-field Acoustic Holography (SONAH) is a Patch Holography method, meaning that it can be applied in cases where the measurement area covers only part of the source surface. The method performs projections directly in the spatial domain, avoiding the use of spatial discrete Fourier transforms and the associated errors. First, an inverse problem is solved using regularization. For each calculation point a multiplication must then be performed with two transfer vectors--one to get the sound pressure and the other to get the particle velocity. Considering SONAH based on sound pressure measurements, existing derivations consider only pressure reconstruction when setting up the inverse problem, so the evanescent wave amplification associated with the calculation of particle velocity is not taken into account in the regularized solution of the inverse problem. The present paper introduces a scaling of the applied plane wave functions that takes the amplification into account, and it is shown that the previously published virtual source-plane retraction has almost the same effect. The effectiveness of the different solutions is verified through a set of simulated measurements. PMID:25373969
NASA Astrophysics Data System (ADS)
Classen, Laura; Herbut, Igor F.; Janssen, Lukas; Scherer, Michael M.
2016-03-01
We study the competition of spin- and charge-density waves and their quantum multicritical behavior for the semimetal-insulator transitions of low-dimensional Dirac fermions. Employing the effective Gross-Neveu-Yukawa theory with two order parameters as a model for graphene and a growing number of other two-dimensional Dirac materials allows us to describe the physics near the multicritical point at which the semimetallic and the spin- and charge-density-wave phases meet. With the help of a functional renormalization group approach, we are able to reveal a complex structure of fixed points, the stability properties of which decisively depend on the number of Dirac fermions Nf. We give estimates for the critical exponents and observe crucial quantitative corrections as compared to the previous first-order ɛ expansion. For small Nf, the universal behavior near the multicritical point is determined by the chiral Heisenberg universality class supplemented by a decoupled, purely bosonic, Ising sector. At large Nf, a novel fixed point with nontrivial couplings between all sectors becomes stable. At intermediate Nf, including the graphene case (Nf=2 ), no stable and physically admissible fixed point exists. Graphene's phase diagram in the vicinity of the intersection between the semimetal, antiferromagnetic, and staggered density phases should consequently be governed by a triple point exhibiting first-order transitions.
Expansion of arbitrary electromagnetic fields in terms of vector spherical wave functions.
Moreira, Wendel Lopes; Neves, Antonio Alvaro Ranha; Garbos, Martin K; Euser, Tijmen G; Cesar, Carlos Lenz
2016-02-01
Since 1908, when Mie reported analytical expressions for the fields scattered by a spherical particle upon incidence of plane-waves, generalizing his analysis for the case of an arbitrary incident wave has been an open question because of the cancellation of the prefactor radial spherical Bessel function. This cancellation was obtained before by our own group for a highly focused beam centered in the objective. In this work, however, we show for the first time how these terms can be canceled out for any arbitrary incident field that satisfies Maxwells equations, and obtain analytical expressions for the beam shape coefficients. We show several examples on how to use our method to obtain analytical beam shape coefficients for: Bessel beams, general hollow waveguide modes and specific geometries such as cylindrical and rectangular. Our method uses the vector potential, which shows the interesting characteristic of being gauge invariant. These results are highly relevant for speeding up numerical calculation of light scattering applications such as the radiation forces acting on spherical particles placed in an arbitrary electromagnetic field, as in an optical tweezers system. PMID:26906812
Yu, Wenbo; Liang, Lei; Lin, Zijing; Ling, Sanliang; Haranczyk, Maciej; Gutowski, Maciej S.
2009-03-01
Energies of different conformers of 22 amino acid molecules and their protonated and deprotonated species were calculated by some density functional theory (DFT; SVWN, B3LYP, B3PW91, MPWB1K, BHandHLYP) and wave function theory (WFT; HF, MP2) methods with the 6-31111G(d,p) basis set to obtain the relative conformer energies, vertical electron detachment energies, deprotonation energies, and proton affinities. Taking the CCSD/6-31111G(d,p) results as the references, the performances of the tested DFT and WFT methods for amino acids with various intramolecular hydrogen bonds were determined. The BHandHLYP method was the best overall performer among the tested DFT methods, and its accuracy was even better than that of the more expensive MP2 method. The computational dependencies of the five DFT methods and the HF and MP2 methods on the basis sets were further examined with the 6-31G(d,p), 6-31111G(d,p), aug-cc-pVDZ, 6-31111G(2df,p), and aug-cc-pVTZ basis sets. The differences between the small and large basis set results have decreased quickly for the hybrid generalized gradient approximation (GGA) methods. The basis set convergence of the MP2 results has been, however, very slow. Considering both the cost and the accuracy, the BHandHLYP functional with the 6-31111G(d,p) basis set is the best choice for the amino acid systems that are rich in hydrogen bonds.
Raghunayakula, Sarita; Subramonian, Divya; Dasso, Mary; Kumar, Rita; Zhang, Xiang-Dong
2015-01-01
Annulate lamellae are cytoplasmic organelles containing stacked sheets of membranes embedded with pore complexes. These cytoplasmic pore complexes at annulate lamellae are morphologically similar to nuclear pore complexes at the nuclear envelope. Although annulate lamellae has been observed in nearly all types of cells, their biological functions are still largely unknown. Here we show that SUMO1-modification of the Ran GTPase-activating protein RanGAP1 not only target RanGAP1 to its known sites at nuclear pore complexes but also to annulate lamellae pore complexes through interactions with the Ran-binding protein RanBP2 and the SUMO-conjugating enzyme Ubc9 in mammalian cells. Furthermore, upregulation of annulate lamellae, which decreases the number of nuclear pore complexes and concurrently increases that of annulate lamellae pore complexes, causes a redistribution of nuclear transport receptors including importin α/β and the exportin CRM1 from nuclear pore complexes to annulate lamellae pore complexes and also reduces the rates of nuclear import and export. Moreover, our results reveal that importin α/β-mediated import complexes initially accumulate at annulate lamellae pore complexes upon the activation of nuclear import and subsequently disassociate for nuclear import through nuclear pore complexes in cells with upregulation of annulate lamellae. Lastly, CRM1-mediated export complexes are concentrated at both nuclear pore complexes and annulate lamellae pore complexes when the disassembly of these export complexes is inhibited by transient expression of a Ran GTPase mutant arrested in its GTP-bound form, suggesting that RanGAP1/RanBP2-activated RanGTP hydrolysis at these pore complexes is required for the dissociation of the export complexes. Hence, our findings provide a foundation for further investigation of how upregulation of annulate lamellae decreases the rates of nuclear transport and also for elucidation of the biological significance of the
Long-Wave Infrared Functional Brain Imaging in Human: A Pilot Study
Joyal, Christian C; Henry, Mylene
2013-01-01
Although some authors suggest to use Long-Wave Infrared (LWIR) sensors to evaluate brain functioning, the link between emissions of LWIR and mental effort is not established. The goal of this pilot study was to determine whether frontal LWIR emissions vary during execution of neuropsychological tasks known to differentially activate the pre-frontal cortex (simple color presentations, induction of the Stroop effect, and a gambling task with real money). Surprisingly, LWIR emissions as measured with bilateral frontal sensors in 47 participants significantly differed between tasks, in the supposed direction (Color
Long-wave infrared functional brain imaging in human: a pilot study.
Joyal, Christian C; Henry, Mylene
2013-01-01
Although some authors suggest to use Long-Wave Infrared (LWIR) sensors to evaluate brain functioning, the link between emissions of LWIR and mental effort is not established. The goal of this pilot study was to determine whether frontal LWIR emissions vary during execution of neuropsychological tasks known to differentially activate the pre-frontal cortex (simple color presentations, induction of the Stroop effect, and a gambling task with real money). Surprisingly, LWIR emissions as measured with bilateral frontal sensors in 47 participants significantly differed between tasks, in the supposed direction (Color
The physical basis for absorption of light. [effects on wave functions of gas molecules and atoms
NASA Technical Reports Server (NTRS)
Pickett, H. M.
1979-01-01
The effects of light absorption on the wave functions of gas-phase molecules and atoms are investigated by high resolution spectral measurements of radiation emerging from a sample. A Stark-modulated sample of methyl fluoride was irradiated at the 102 GHz rotational transition and the emergent radiation was resolved by means of a spectrum analyzer. For signal oscillator frequencies below or above the molecular resonance by one modulation frequency, the amplitudes of the upper and lower modulation sidebands are found to be of nonuniform intensity, which is inconsistent with amplitude modulation. Emission due to polarization is, however, calculated to be consistent with the results observed, indicating that light absorption should be considered as a subtractive stimulated emission.
Testing Spontaneous Wave-Function Collapse Models on Classical Mechanical Oscillators
NASA Astrophysics Data System (ADS)
Diósi, Lajos
2015-02-01
We show that the heating effect of spontaneous wave-function collapse models implies an experimentally significant increment Δ Tsp of equilibrium temperature in a mechanical oscillator. The obtained new form Δ Tsp is linear in the oscillator's relaxation time τ and independent of the mass. The oscillator can be in a classical thermal state, also the effect Δ Tsp is classical for a wide range of frequencies and quality factors. We note that the test of Δ Tsp does not necessitate quantum state monitoring just tomography. In both the gravity-related and the continuous spontaneous localization models the strong-effect edge of their parameter range can be challenged in existing experiments on classical oscillators. For the continuous spontaneous localization theory, the conjectured highest collapse rate parameter values become immediately constrained by evidences from current experiments on extreme slow-ring-down oscillators.
Hadronic Spectra and Light-Front Wave Functions in Holographic QCD
Brodsky, Stanley J.; Teramond, Guy F. de
2006-05-26
We show how the string amplitude {phi}(z) defined on the fifth dimension in AdS{sub 5} space can be precisely mapped to the light-front wave functions of hadrons in physical space-time. We find an exact correspondence between the holographic variable z and an impact variable {zeta}, which represents the measure of transverse separation of the constituents within the hadrons. In addition, we derive effective four dimensional Schroedinger equations for the bound states of massless quarks and gluons which exactly reproduce the anti-de Sitter conformal field theory results and give a realistic description of the light-quark meson and baryon spectrum as well as the form factors for spacelike Q{sup 2}. Only one parameter which sets the mass scale, {lambda}{sub QCD}, is introduced.
Optimal spatial filtering and transfer function for SAR ocean wave spectra
NASA Technical Reports Server (NTRS)
Beal, R. C.; Tilley, D. G.
1981-01-01
The impulse response of the SAR system is not a delta function and the spectra represent the product of the underlying image spectrum with the transform of the impulse response which must be removed. A digitally computed spectrum of SEASAT imagery of the Atlantic Ocean east of Cape Hatteras was smoothed with a 5 x 5 convolution filter and the trend was sampled in a direction normal to the predominant wave direction. This yielded a transform of a noise-like process. The smoothed value of this trend is the transform of the impulse response. This trend is fit with either a second- or fourth-order polynomial which is then used to correct the entire spectrum. A 16 x 16 smoothing of the spectrum shows the presence of two distinct swells. Correction of the effects of speckle is effected by the subtraction of a bias from the spectrum.
Optimal spatial filtering and transfer function for SAR ocean wave spectra
NASA Astrophysics Data System (ADS)
Beal, R. C.; Tilley, D. G.
1981-06-01
The impulse response of the SAR system is not a delta function and the spectra represent the product of the underlying image spectrum with the transform of the impulse response which must be removed. A digitally computed spectrum of SEASAT imagery of the Atlantic Ocean east of Cape Hatteras was smoothed with a 5 x 5 convolution filter and the trend was sampled in a direction normal to the predominant wave direction. This yielded a transform of a noise-like process. The smoothed value of this trend is the transform of the impulse response. This trend is fit with either a second- or fourth-order polynomial which is then used to correct the entire spectrum. A 16 x 16 smoothing of the spectrum shows the presence of two distinct swells. Correction of the effects of speckle is effected by the subtraction of a bias from the spectrum.
Universal Wave-Function Overlap and Universal Topological Data from Generic Gapped Ground States.
Moradi, Heidar; Wen, Xiao-Gang
2015-07-17
We propose a way-universal wave-function overlap-to extract universal topological data from generic ground states of gapped systems in any dimensions. Those extracted topological data might fully characterize the topological orders with a gapped or gapless boundary. For nonchiral topological orders in (2+1)D, these universal topological data consist of two matrices S and T, which generate a projective representation of SL(2,Z) on the degenerate ground state Hilbert space on a torus. For topological orders with a gapped boundary in higher dimensions, these data constitute a projective representation of the mapping class group MCG(M^{d}) of closed spatial manifold M^{d}. For a set of simple models and perturbations in two dimensions, we show that these quantities are protected to all orders in perturbation theory. These overlaps provide a much more powerful alternative to the topological entanglement entropy and allow for more efficient numerical implementations. PMID:26230815
Wave-Function Scarring Effects in Open Stadium Shaped Quantum Dots
NASA Astrophysics Data System (ADS)
Akis, Richard; Ferry, David
1997-03-01
We have found that the low field magneto-conductance of open, stadium shaped quantum dots is periodic, indicating that only a few, regular orbits dominate the transport, despite the fact that this structure is classically chaotic. Our results, which agree with experiment, are obtained by a fully quantum mechanical treatment. Evidence for the regular orbits is seen in heavily scarred wave-functions. Some scars recur periodically, in correspondence to peaks in the power spectrum. Crucial in exciting particular orbits, are the quantized modes in the leads, which cause the electrons to enter the dot in collimated and angled beams. These orbits can be quite long in comparison to the device size. Additional information, including downloadable copies of related papers, can be obtained from our web site: http://www.eas.asu.edu/ ~ nano/nano.html .
Two-loop partition function in the planar plane-wave matrix model
NASA Astrophysics Data System (ADS)
Spradlin, Marcus; Van Raamsdonk, Mark; Volovich, Anastasia
2004-12-01
We perform two independent calculations of the two-loop partition function for the 't Hooft large N limit of the plane-wave matrix model, conjectured to be dual to the decoupled little string theory of a single spherical type IIA NS5-brane. The first is via a direct two-loop path-integral calculation in the matrix model, while the second employs the one-loop dilatation operator of four-dimensional N = 4 Yang-Mills theory truncated to the SU (2 | 4) subsector. We find precise agreement between the results of the two calculations. Various polynomials appearing in the result have rather special properties, possibly related to the large symmetry algebra of the theory or to integrability.
NASA Astrophysics Data System (ADS)
Roostaei, B.; Ermler, W. C.
2012-03-01
A procedure for calculating electric dipole transition moments and permanent dipole moments from spin-orbit configuration interaction (SOCI) wave functions has been developed in the context of the COLUMBUS ab initio electronic structure programs. The SOCI procedure requires relativistic effective core potentials and their corresponding spin-orbit coupling operators to define the molecular Hamiltonian, electric dipole transition moment and permanent dipole moment matrices. The procedure can be used for any molecular system for which the COLUMBUS SOCI circuits are applicable. Example applications are reported for transition moments and dipole moments for a series of electronic states of LiBe and LiSr defined in diatomic relativistic ωω-coupling.
Quantum chemistry without wave functions: two-electron reduced density matrices.
Mazziotti, David A
2006-03-01
For 50 years, progress toward the direct calculation of the ground-state two-electron reduced density matrix (2-RDM) was stymied from an inability to constrain the 2-RDM to represent an N-electron wave function. Recent advances in theory and optimization have realized the direct calculation of the 2-RDM. A variational 2-RDM procedure, using first-order semidefinite programming, has been shown to capture multireference correlation effects important at nonequilibrium geometries [Mazziotti, Phys. Rev. Lett. 2004, 93, No. 213001]. This method emerged from research on a nonvariational calculation of the 2-RDM by the contracted Schrödinger equation. Both approaches will be discussed and illustrated. PMID:16548509
Finite-element-method expectation values for correlated two-electron wave functions
Ackermann, J.
1995-09-01
The Schroedinger equation for the ground state of correlated two-electron atoms is treated by an accurate finite-element method (FEM) yielding energy eigenvalues of {minus}2.903 724 377 021 a.u. for the helium atom and {minus}0.527 751 016 532 a.u. for the hydrogen ion H{sup {minus}}. By means of an adaptive multilevel grid refinement the FEM energy eigenvalue is improved to a precision of 1{times}10{sup {minus}11} a.u., which is comparable to results obtained with sophisticated global basis sets. The local and overall precision of the FEM wave function approximation is studied and discussed. Benchmark values for the expectation values {l_angle}{ital r}{sup 2}{r_angle}, {l_angle}{ital r}{r_angle}, {l_angle}1/{ital r}{r_angle}, and {l_angle}1/{ital r}{sub 12}{r_angle} are presented.
Numerical Analysis of Quasiholes of the Moore-Read Wave Function
NASA Astrophysics Data System (ADS)
Baraban, M.; Zikos, G.; Bonesteel, N.; Simon, S. H.
2009-08-01
We demonstrate numerically that non-Abelian quasihole (qh) excitations of the ν=5/2 fractional quantum Hall state have some of the key properties necessary to support quantum computation. We find that as the qh spacing is increased, the unitary transformation which describes winding two qh’s around each other converges exponentially to its asymptotic limit and that the two orthogonal wave functions describing a system with four qh’s become exponentially degenerate. We calculate the length scales for these two decays to be ξU≈2.7ℓ0 and ξE≈2.3ℓ0, respectively. Additionally, we determine which fusion channel is lower in energy when two qh’s are brought close together.
NASA Astrophysics Data System (ADS)
Pierdominici-Sottile, Gustavo; Palma, Juliana
2009-09-01
We have evaluated the kinetic isotope effect (KIE) in the proton transfer step that determines the oxidation rate of methylamine, catalyzed by the enzyme methylamine dehydrogenase. Calculations were performed with the wave function propagation (WFP) approach, recently implemented to estimate the KIE in soybean lipoxygenase-1. Two different versions of the method were applied. Both of them produced results which are close to the experimental value of 16.8 ± 0.5. The calculation required the development of a valence-bond parameterization. In the article, we describe the procedure followed to obtain these parameters, present the results of several tests employed to assess their performance and give details of the two versions of the WFP approach used to evaluate the KIE.
Testing spontaneous wave-function collapse models on classical mechanical oscillators.
Diósi, Lajos
2015-02-01
We show that the heating effect of spontaneous wave-function collapse models implies an experimentally significant increment ΔT(sp) of equilibrium temperature in a mechanical oscillator. The obtained new form ΔT(sp) is linear in the oscillator's relaxation time τ and independent of the mass. The oscillator can be in a classical thermal state, also the effect ΔT(sp) is classical for a wide range of frequencies and quality factors. We note that the test of ΔT(sp) does not necessitate quantum state monitoring just tomography. In both the gravity-related and the continuous spontaneous localization models the strong-effect edge of their parameter range can be challenged in existing experiments on classical oscillators. For the continuous spontaneous localization theory, the conjectured highest collapse rate parameter values become immediately constrained by evidences from current experiments on extreme slow-ring-down oscillators. PMID:25699424
{alpha}-decay hindrance factors: A probe of mean-field wave functions
Karlgren, D.; Liotta, R.J.; Wyss, R.; Huyse, M.; Vel, K. van de; Duppen, P. van
2006-06-15
A simple model to calculate {alpha}-decay hindrance factors (HF) with special emphasis on the shape coexistence in the Pb-Po region is presented. Using deformation values obtained from potential energy surface (PES) calculations as the only input, hindrance factors for the {alpha} decay of Rn and Po isotopes are calculated. The fair agreement between experimental and theoretical hindrance factors suggest that the wave function obtained from the energy minima of the PES calculations contains an important part of the correlations that play a role for the {alpha} decay. The model is applicable to shape coexistence in the Po and Pb region when minima are well defined. The calculated HF that emerge from these calculations render a different interpretation than the commonly assumed n-particle n-hole picture of the intruder states in the Pb region.
Fast plane wave density functional theory molecular dynamics calculations on multi-GPU machines
Jia, Weile; University of Chinese Academy of Sciences, Beijing ; Fu, Jiyun; University of Chinese Academy of Sciences, Beijing ; Cao, Zongyan; Wang, Long; Chi, Xuebin; Gao, Weiguo; MOE Key Laboratory of Computational Physical Sciences, Fudan University, Shanghai ; Wang, Lin-Wang
2013-10-15
Plane wave pseudopotential (PWP) density functional theory (DFT) calculation is the most widely used method for material simulations, but its absolute speed stagnated due to the inability to use large scale CPU based computers. By a drastic redesign of the algorithm, and moving all the major computation parts into GPU, we have reached a speed of 12 s per molecular dynamics (MD) step for a 512 atom system using 256 GPU cards. This is about 20 times faster than the CPU version of the code regardless of the number of CPU cores used. Our tests and analysis on different GPU platforms and configurations shed lights on the optimal GPU deployments for PWP-DFT calculations. An 1800 step MD simulation is used to study the liquid phase properties of GaInP.
Sykes, Lynn R.; Wiggins, Graham C.
1986-01-01
Surface and body wave magnitudes are determined for 15 U.S.S.R. underground nuclear weapons tests conducted at Novaya Zemlya between 1964 and 1976 and are used to estimate yields. These events include the largest underground explosions detonated by the Soviet Union. A histogram of body wave magnitude (mb) values indicates a clustering of explosions at a few specific yields. The most pronounced cluster consists of six explosions of yield near 500 kilotons. Several of these seem to be tests of warheads for major strategic systems that became operational in the late 1970s. The largest Soviet underground explosion is estimated to have a yield of 3500 ± 600 kilotons, somewhat smaller than the yield of the largest U.S. underground test. A preliminary estimation of the significance of tectonic release is made by measuring the amplitude of Love waves. The bias in mb for Novaya Zemlya relative to the Nevada test site is about 0.35, nearly identical to that of the eastern Kazakhstan test site relative to Nevada. PMID:16593645
Spectroscopic properties of nuclear skyrme energy density functionals.
Tarpanov, D; Dobaczewski, J; Toivanen, J; Carlsson, B G
2014-12-19
We address the question of how to improve the agreement between theoretical nuclear single-particle energies (SPEs) and observations. Empirically, in doubly magic nuclei, the SPEs can be deduced from spectroscopic properties of odd nuclei that have one more or one less neutron or proton. Theoretically, bare SPEs, before being confronted with observations, must be corrected for the effects of the particle vibration coupling (PVC). In the present work, we determine the PVC corrections in a fully self-consistent way. Then, we adjust the SPEs, with PVC corrections included, to empirical data. In this way, the agreement with observations, on average, improves; nevertheless, large discrepancies still remain. We conclude that the main source of disagreement is still in the underlying mean fields, and not in including or neglecting the PVC corrections. PMID:25554877
A TOCA/CDC-42/PAR/WAVE functional module required for retrograde endocytic recycling
Bai, Zhiyong; Grant, Barth D.
2015-01-01
Endosome-to-Golgi transport is required for the function of many key membrane proteins and lipids, including signaling receptors, small-molecule transporters, and adhesion proteins. The retromer complex is well-known for its role in cargo sorting and vesicle budding from early endosomes, in most cases leading to cargo fusion with the trans-Golgi network (TGN). Transport from recycling endosomes to the TGN has also been reported, but much less is understood about the molecules that mediate this transport step. Here we provide evidence that the F-BAR domain proteins TOCA-1 and TOCA-2 (Transducer of Cdc42 dependent actin assembly), the small GTPase CDC-42 (Cell division control protein 42), associated polarity proteins PAR-6 (Partitioning defective 6) and PKC-3/atypical protein kinase C, and the WAVE actin nucleation complex mediate the transport of MIG-14/Wls and TGN-38/TGN38 cargo proteins from the recycling endosome to the TGN in Caenorhabditis elegans. Our results indicate that CDC-42, the TOCA proteins, and the WAVE component WVE-1 are enriched on RME-1–positive recycling endosomes in the intestine, unlike retromer components that act on early endosomes. Furthermore, we find that retrograde cargo TGN-38 is trapped in early endosomes after depletion of SNX-3 (a retromer component) but is mainly trapped in recycling endosomes after depletion of CDC-42, indicating that the CDC-42–associated complex functions after retromer in a distinct organelle. Thus, we identify a group of interacting proteins that mediate retrograde recycling, and link these proteins to a poorly understood trafficking step, recycling endosome-to-Golgi transport. We also provide evidence for the physiological importance of this pathway in WNT signaling. PMID:25775511
NASA Astrophysics Data System (ADS)
Osmane, A.; Hamza, A. M.; Meziane, K.
2007-12-01
Recent results from the Cluster mission have stimulated theoretical investigations and simulations to explain ion distribution functions observed in the quasi-perp bow shock. [Meziane et al., 2001] High-time resolution observations have revealed distributions of gyrating ions that are gyrophase-bunched. When not produced at the shock, such distributions are believed to be resulting from interactions between field-aligned beams and low frequency beam-driven waves (ω <Ømega) [Hamza et al., 2005] The Conventional models used to account for such distributions assume that the waves are purely transverse, and that they propagate parallel to the ambient magnetic field. However observations indicate that these waves are propagating obliquely (θ ≤ 30 ° ) with respect to the ambient magnetic field [Meziane et al., 2001]. A theoretical investigation of the non-relativistic wave-particle interaction in a background magnetic field with the electromagnetic wave propagating obliquely has been addressed previously, resulting in a dynamical system describing the wave interaction with a single ion in the absence of dissipation mechanisms. [Hamza et al., 2005] This dynamical system can be numerically integrated to construct the ion distribution functions by seeding the particles with different initial conditions. We compute the particle orbits and simulate the time evolution of the distribution functions based on Liouville's theorem of phase space density conservation. This exercise can then provide insights on the particle dynamics away from the shock. Meziane, K., C. Mazelle, R.P. Lin, D. LeQueau, D.E. Larson, G.K. Parks, R.P. Lepping (2001), Three dimensional observations of gyrating ions distributions far upstream from the Earth's bow shock and their association with low-frequency waves, J. Geophys. Res. 106, 5731 Hamza, A. M., K. Meziane, and C. Mazelle (2006), Oblique propagation and nonlinear wave particle processes, J. Geophys. Res., 111, A04104
2.5D S-wave velocity model of the TESZ area in northern Poland from receiver function analysis
NASA Astrophysics Data System (ADS)
Wilde-Piorko, Monika; Polkowski, Marcin; Grad, Marek
2016-04-01
Receiver function (RF) locally provides the signature of sharp seismic discontinuities and information about the shear wave (S-wave) velocity distribution beneath the seismic station. The data recorded by "13 BB Star" broadband seismic stations (Grad et al., 2015) and by few PASSEQ broadband seismic stations (Wilde-Piórko et al., 2008) are analysed to investigate the crustal and upper mantle structure in the Trans-European Suture Zone (TESZ) in northern Poland. The TESZ is one of the most prominent suture zones in Europe separating the young Palaeozoic platform from the much older Precambrian East European craton. Compilation of over thirty deep seismic refraction and wide angle reflection profiles, vertical seismic profiling in over one hundred thousand boreholes and magnetic, gravity, magnetotelluric and thermal methods allowed for creation a high-resolution 3D P-wave velocity model down to 60 km depth in the area of Poland (Grad et al. 2016). On the other hand the receiver function methods give an opportunity for creation the S-wave velocity model. Modified ray-tracing method (Langston, 1977) are used to calculate the response of the structure with dipping interfaces to the incoming plane wave with fixed slowness and back-azimuth. 3D P-wave velocity model are interpolated to 2.5D P-wave velocity model beneath each seismic station and synthetic back-azimuthal sections of receiver function are calculated for different Vp/Vs ratio. Densities are calculated with combined formulas of Berteussen (1977) and Gardner et al. (1974). Next, the synthetic back-azimuthal sections of RF are compared with observed back-azimuthal sections of RF for "13 BB Star" and PASSEQ seismic stations to find the best 2.5D S-wave models down to 60 km depth. National Science Centre Poland provided financial support for this work by NCN grant DEC-2011/02/A/ST10/00284.
Afanasjev, A. V.
2015-10-15
The assessment of the global performance of the state-of-the-art covariant energy density functionals and related theoretical uncertainties in the description of ground state observables has recently been performed. Based on these results, the correlations between global description of binding energies and nuclear matter properties of covariant energy density functionals have been studied in this contribution.
US Nuclear Regulatory Commission organization charts and functional statements
1996-08-19
This document is the organizational chart for the US NRC. It contains organizational structure and functional statements for the following: (1) the Commission, (2) committees and boards, (3) staff offices, (4) office of the Inspector General, (5) executive director for operations, (6) program offices, and (7) regional offices.
NASA Astrophysics Data System (ADS)
Rodgers, A. J.; Lay, T.
2014-12-01
Observations of nuclear explosions ubiquitously reveal shear-waves in the form of high-frequency Sn and Lg at regional distances and long-period surface waves at teleseismic distances. While a number of mechanisms have been shown to generate shear-waves from explosions, including non-linear processes near the source, elastic scattering and tectonic release, it is likely that all mechanisms act to some extent in each emplacement scenario. We performed numerical simulations of seismic ground motions excited by shallow explosions in the presence of rough surface topography to investigate elastic scattering and mode-conversion mechanisms of S-wave generation. Massively parallel simulations were performed at high-resolution to capture the high frequencies (up to 8 Hz) of interest to low-yield nuclear explosion monitoring. Simulations were performed with SW4, an elastic finite difference code that uses a conforming curvilinear mesh to model the near-surface region with a non-planar free surface. Results show that the rough free surface generates significant S-waves by P-to-Rg scattering. We performed simulations with real surface topography from the North Korean (DPRK) nuclear test site and synthetic stochastic topography to investigate how surface topography governs local and regional distance S-waves. We find that S-wave amplitudes along the surface in the presence of topography are increased several-fold on average within 10 km of the source. Topographic scattering leads to SH amplitudes of up to 50% of SV within 10 km, leading to equipartitioning of shear wave energy on the horizontal components. Scattered energy between the direct P and Rg waves has the amplitude spectra of the direct P-wave but travels with the Rg velocity, clearly illustrating the P-to-Rg mechanism for shear-wave generation. The amplitude spectra of Rg waves in the presence of topography are shaped by the low frequency (0.5-2.5 Hz) peaked spectrum of the flat case plus the high frequency (> 2 Hz
NASA Astrophysics Data System (ADS)
Sinmyo, R.; Glazyrin, K.; McCammon, C.; Kupenko, I.; Kantor, A.; Potapkin, V.; Chumakov, A. I.; Rüffer, R.; Dubrovinsky, L.
2014-04-01
Elastic wave velocities of minerals are important for constraining the chemistry, structure and dynamics of the Earth's mantle based on the comparison between laboratory-based measurements and seismic observations. As the second most abundant phase in the Earth's lower mantle, (Mg,Fe)O ferropericlase has been the focus of numerous studies measuring the elastic wave velocities using various methods such as Brillouin spectroscopy and ultrasonic measurements. Recently, nuclear inelastic scattering (NIS) has been used to determine elastic wave velocities of iron-bearing phases. However, the elastic wave velocities of ferropericlase obtained using NIS are considerably lower than the velocities obtained by other methods, even at ambient conditions. One possible source of this discrepancy is the local nature of the NIS method. In order to test this hypothesis, we have investigated six ferropericlase samples with various iron contents using NIS. The Debye sound velocities calculated using the conventional method of NIS analysis are consistent with previous results obtained using NIS, yet the values are significantly lower than those obtained using ultrasonics and Brillouin spectroscopy. If the Debye sound velocities are re-calculated based on a mixture of different iron next-neighbour configurations with different compositions, the Debye sound velocities determined by NIS agree well with the results from other methods. Our new model was also successfully applied to high-pressure NIS data taken from the literature. Our results constitute an important step towards a better understanding of how to obtain reliable sound velocities of iron-bearing mantle minerals from NIS measurements.
Rabanal-León, Walter A; Murillo-López, Juliana A; Páez-Hernández, Dayán; Arratia-Pérez, Ramiro
2015-09-24
The high interest in lanthanide chemistry, and particularly in their luminescence, has been encouraged by the need of understanding the lanthanide chemical coordination and how the design of new luminescent materials can be affected by this. This work is focused on the understanding of the electronic structure, bonding nature, and optical properties of a set of lanthanide hexaaza macrocyclic complexes, which can lead to potential optical applications. Here we found that the DFT ground state of the open-shell complexes are mainly characterized by the manifold of low lying f states, having small HOMO-LUMO energy gaps. The results obtained from the wave function theory calculations (SO-RASSI) put on evidence the multiconfigurational character of their ground state and it is observed that the large spin-orbit coupling and the weak crystal field produce a strong mix of the ground and the excited states. The electron localization function (ELF) and the energy decomposition analysis (EDA) support the idea of a dative interaction between the macrocyclic ligand and the lanthanide center for all the studied systems; noting that, this interaction has a covalent character, where the d-orbital participation is evidenced from NBO analysis, leaving the f shell completely noninteracting in the chemical bonding. From the optical part we observed in all cases the characteristic intraligand (IL) (π-π*) and ligand to metal charge-transfer (LMCT) bands that are present in the ultraviolet and visible regions, and for the open-shell complexes we found the inherent f-f electronic transitions on the visible and near-infrared region. PMID:26325624
NASA Astrophysics Data System (ADS)
Rangwala, Abbas A.; Rao, Jyoti A.
1990-05-01
Using the Bargmann-Darboux method, the Bäcklund transformations, n-soliton solutions and corresponding wave functions of the Kaup-Newell and Wadati-Konno-Ichikawa systems are obtained. These results culminate in an algebraic recursive procedure for the determination of multisoliton solutions and their wave functions of the derivative and mixed derivative nonlinear Schrödinger equations iQt+Qxx∓iα(||Q||2Q)x ±β||Q||2Q=0, α>0, β≥0.
NASA Astrophysics Data System (ADS)
Aitala, E. M.; Amato, S.; Anjos, J. C.; Appel, J. A.; Ashery, D.; Banerjee, S.; Bediaga, I.; Blaylock, G.; Bracker, S. B.; Burchat, P. R.; Burnstein, R. A.; Carter, T.; Carvalho, H. S.; Copty, N. K.; Cremaldi, L. M.; Darling, C.; Denisenko, K.; Deval, S.; Fernandez, A.; Fox, G. F.; Gagnon, P.; Gerzon, S.; Gobel, C.; Gounder, K.; Halling, A. M.; Herrera, G.; Hurvits, G.; James, C.; Kasper, P. A.; Kwan, S.; Langs, D. C.; Leslie, J.; Lichtenstadt, J.; Lundberg, B.; Maytal-Beck, S.; Meadows, B.; de Mello Neto, J. R.; Mihalcea, D.; Milburn, R. H.; de Miranda, J. M.; Napier, A.; Nguyen, A.; D'Oliveira, A. B.; O'Shaughnessy, K.; Peng, K. C.; Perera, L. P.; Purohit, M. V.; Quinn, B.; Radeztsky, S.; Rafatian, A.; Reay, N. W.; Reidy, J. J.; Dos Reis, A. C.; Rubin, H. A.; Sanders, D. A.; Santha, A. K.; Santoro, A. F.; Schwartz, A. J.; Sheaff, M.; Sidwell, R. A.; Slaughter, A. J.; Sokoloff, M. D.; Solano, J.; Stanton, N. R.; Stefanski, R. J.; Stenson, K.; Summers, D. J.; Takach, S.; Thorne, K.; Tripathi, A. K.; Watanabe, S.; Weiss-Babai, R.; Wiener, J.; Witchey, N.; Wolin, E.; Yang, S. M.; Yi, D.; Yoshida, S.; Zaliznyak, R.; Zhang, C.
2001-05-01
We present the first direct measurements of the pion valence-quark momentum distribution which is related to the square of the pion light-cone wave function. The measurements were carried out using data on diffractive dissociation of 500 GeV/c π- into dijets from a platinum target at Fermilab experiment E791. The results show that the \\|qq¯> light-cone asymptotic wave function describes the data well for Q2~10 \\(GeV/c\\)2 or more. We also measured the transverse momentum distribution of the diffractive dijets.
Moments of ϕ meson spectral functions in vacuum and nuclear matter
NASA Astrophysics Data System (ADS)
Gubler, Philipp; Weise, Wolfram
2015-12-01
Moments of the ϕ meson spectral function in vacuum and in nuclear matter are analyzed, combining a model based on chiral SU (3) effective field theory (with kaonic degrees of freedom) and finite-energy QCD sum rules. For the vacuum we show that the spectral density is strongly constrained by a recent accurate measurement of the e+e- →K+K- cross section. In nuclear matter the ϕ spectrum is modified by interactions of the decay kaons with the surrounding nuclear medium, leading to a significant broadening and an asymmetric deformation of the ϕ meson peak. We demonstrate that both in vacuum and nuclear matter, the first two moments of the spectral function are compatible with finite-energy QCD sum rules. A brief discussion of the next-higher spectral moment involving strange four-quark condensates is also presented.
Manual of functions, assignments, and responsibilities for nuclear safety: Revision 2
Not Available
1994-10-15
The FAR Manual is a convenient easy-to-use collection of the functions, assignments, and responsibilities (FARs) of DOE nuclear safety personnel. Current DOE directives, including Orders, Secretary of Energy Notices, and other assorted policy memoranda, are the source of this information and form the basis of the FAR Manual. Today, the majority of FARs for DOE personnel are contained in DOE`s nuclear safety Orders. As these Orders are converted to rules in the Code of Federal Regulations, the FAR Manual will become the sole source for information relating to the functions, assignments, responsibilities of DOE nuclear safety personnel. The FAR Manual identifies DOE directives that relate to nuclear safety and the specific DOE personnel who are responsible for implementing them. The manual includes only FARs that have been extracted from active directives that have been approved in accordance with the procedures contained in DOE Order 1321.1B.
Svinarenko, A. A.; Loboda, A. V.; Sukharev, D. E.; Dubrovskaya, Yu. V.; Mudraya, N. V.; Serga, I. N.; Glushkov, A. V.
2010-05-04
We report the further development of an effective approach to construction of the electron Green's function (GF) for the Dirac equation with a complex energy and non-singular central nuclear potential. The nuclear charge distribution and the corresponding nuclear potential are received within the relativistic mean field (RMF) model. The Green's function is usually represented as a combination of two fundamental solutions of the Dirac equation. In the numerical procedure we use the Ivanov-Ivanova effective numerical algorithm and reduce a definition of the Dirac equation fundamental solutions to solving the system of differential equations, which includes the differential equations for the RMF nuclear potential too. As an application, we estimate the self-energy shift correction to atomic levels energies within the Mohr covariant procedure and presented GF approach and calculate the transitions energies for some heavy Li-like multi-charged ions within the QED many-body perturbation theory formalism.
NASA Astrophysics Data System (ADS)
Shen, Chun; Sun, Meina
2013-08-01
This paper is devoted to studying the interactions of elementary waves for a model of a scalar conservation law with a flux function involving discontinuous coefficients. In order to cover all the situations completely, we take the initial data as three piecewise constant states and the middle region is regarded as the perturbed region with small distance. It is proved that the Riemann solutions are stable under the local small perturbations of the Riemann initial data by letting the perturbed parameter tend to zero. The proof is based on the detailed analysis of the interactions of stationary wave discontinuities with shock waves and rarefaction waves. Moreover, the global structures and large time asymptotic behaviors of the solutions are constructed and analyzed case by case.
KPNB1 mediates PER/CRY nuclear translocation and circadian clock function
Lee, Yool; Jang, A Reum; Francey, Lauren J; Sehgal, Amita; Hogenesch, John B
2015-01-01
Regulated nuclear translocation of the PER/CRY repressor complex is critical for negative feedback regulation of the circadian clock of mammals. However, the precise molecular mechanism is not fully understood. Here, we report that KPNB1, an importin β component of the ncRNA repressor of nuclear factor of activated T cells (NRON) ribonucleoprotein complex, mediates nuclear translocation and repressor function of the PER/CRY complex. RNAi depletion of KPNB1 traps the PER/CRY complex in the cytoplasm by blocking nuclear entry of PER proteins in human cells. KPNB1 interacts mainly with PER proteins and directs PER/CRY nuclear transport in a circadian fashion. Interestingly, KPNB1 regulates the PER/CRY nuclear entry and repressor function, independently of importin α, its classical partner. Moreover, inducible inhibition of the conserved Drosophila importin β in lateral neurons abolishes behavioral rhythms in flies. Collectively, these data show that KPNB1 is required for timely nuclear import of PER/CRY in the negative feedback regulation of the circadian clock. DOI: http://dx.doi.org/10.7554/eLife.08647.001 PMID:26319354
Multi-functional surface acoustic wave sensor for monitoring enviromental and structural condition
NASA Astrophysics Data System (ADS)
Furuya, Y.; Kon, T.; Okazaki, T.; Saigusa, Y.; Nomura, T.
2006-03-01
As a first step to develop a health monitoring system with active and embedded nondestructive evaluation devices for the machineries and structures, multi-functional SAW (surface acoustic wave) device was developed. A piezoelectric LiNbO3(x-y cut) materials were used as a SAW substrate on which IDT(20μm pitch) was produced by lithography. On the surface of a path of SAW between IDTs, environmentally active material films of shape memory Ti50Ni41Cu(at%) with non-linear hysteresis and superelastic Ti48Ni43Cu(at%) with linear deformation behavior were formed by magnetron-sputtering technique. In this study, these two kinds of shape memory alloys SMA) system were used to measure 1) loading level, 2) phase transformation and 3)stress-strain hysteresis under cyclic loading by utilizing their linearity and non-linearity deformation behaviors. Temperature and stress dependencies of SAW signal were also investigated in the non-sputtered film state. Signal amplitude and phase change of SAW were chosen to measure as the sensing parameters. As a result, temperature, stress level, phase transformation in SMA depending on temperature and mechanical damage accumulation could be measured by the proposed multi-functional SAW sensor. Moreover, the wireless SAW sensing system which has a unique feature of no supplying electric battery was constructed, and the same characteristic evaluation is confirmed in comparison with wired case.
Maouche, Naima; Ktari, Nadia; Bakas, Idriss; Fourati, Najla; Zerrouki, Chouki; Seydou, Mahamadou; Maurel, François; Chehimi, Mohammed Mehdi
2015-11-01
A surface acoustic wave sensor operating at 104 MHz and functionalized with a polypyrrole molecularly imprinted polymer has been designed for selective detection of dopamine (DA). Optimization of pyrrole/DA ratio, polymerization and immersion times permitted to obtain a highly selective sensor, which has a sensitivity of 0.55°/mM (≈ 550 Hz/mM) and a detection limit of ≈ 10 nM. Morphology and related roughness parameters of molecularly imprinted polymer surfaces, before and after extraction of DA, as well as that of the non imprinted polymer were characterized by atomic force microscopy. The developed chemosensor selectively recognized dopamine over the structurally similar compound 4-hydroxyphenethylamine (referred as tyramine), or ascorbic acid,which co-exists with DA in body fluids at a much higher concentration. Selectivity tests were also carried out with dihydroxybenzene, for which an unexpected phase variation of order of 75% of the DA one was observed. Quantum chemical calculations, based on the density functional theory, were carried out to determine the nature of interactions between each analyte and the PPy matrix and the DA imprinted PPy polypyrrole sensing layer in order to account for the important phase variation observed during dihydroxybenzene injection. PMID:26095144